After internalization, transmembrane receptors (TMRs) are typically recycled back to the cell surface or targeted for degradation. Efficient TMR trafficking is critical for regulation of several processes, including signal transduction pathways, development, and disease. Here, we determined that trafficking of the angiogenic receptor neuropilin-1 (NRP-1) is abrogated by the liver kinase B1 (LKB1), a serine-threonine kinase of the calcium calmodulin family. We found that aberrant NRP-1 expression in tumor cells from patients with lung adenocarcinoma is associated with decreased levels of LKB1. In cultured lung cells, LKB1 accentuated formation of a complex between NRP-1 and RAB7 in late endosomes. LKB1 specifically bound GTP-bound RAB7, but not a dominant-negative GDP-bound form of RAB7, promoting rapid transfer and lysosome degradation of NRP-1. siRNA-mediated depletion of RAB7 disrupted the transfer of NRP-1 to the lysosome, resulting in recovery of the receptor as well as increased tumor growth and angiogenesis. Together, our findings indicate that LKB1 functions as a RAB7 effector and suppresses angiogenesis by promoting the cellular trafficking of NRP-1 from RAB7 vesicles to the lysosome for degradation. Furthermore, these data suggest that LKB1 and NRP-1 have potential as therapeutic targets for limiting tumorigenesis.
Rab5 is a key regulator of early endocytosis by promoting early endosomal fusion and motility. In this study, we have unexpectedly found distinct properties of the two Rab5 homologs (MoRab5A and MoRab5B) from Magnaporthe oryzae, a pathogenic fungus in plants whose infection causes rice blast disease. Like mammalian Rab5, MoRab5A and MoRab5B can bind to several Rab5 effectors in a GTP-dependent manner, including EEA1, Rabenosyn-5, and Rabaptin-5. However, MoRab5A shows distinct binding characteristics in the sense that both the wild-type and the GTP hydrolysis-defective constitutively active mutant bind the effectors equally well in GST pull-down assays, suggesting that MoRab5A is defective in GTP hydrolysis and mostly in the GTP-bound conformation in the cell. Indeed, GTP hydrolysis assays indicate that MoRab5A GTPase activity is dramatically lower than MoRab5B and human Rab5 and is insensitive to RabGAP5 stimulation. We have further identified a Pro residue in the switch I region largely responsible for the distinct MoRab5A properties by characterization of MoRab5A and MoRab5B chimeras and mutagenesis. The differences between MoRab5A and MoRab5B extend to their functions in the cell. Although they both target to early endosomes, only MoRab5B closely resembles human Rab5 in promoting early endosome fusion and stimulating fluid phase endocytosis. In contrast, MoRab5A correlates with another related early endosomal Rab, Rab22, in terms of the presence of the switch I Pro residue and the blocked GTPase activity. Our data thus identify MoRab5B as the Rab5 ortholog and suggest that MoRab5A specializes to perform a non-redundant function in endosomal sorting.
Axon guidance (pathfinding) wires the brain during development and is regulated by various attractive and repulsive cues. Semaphorin 3A (Sema3A) is a repulsive cue, inducing the collapse of axon growth cones. In the mammalian forebrain, the corpus callosum is the major commissure that transmits information flow between the two hemispheres, and contralateral axons assemble into well-defined tracts. We found that the patterning of callosal axon projections in rodent layer II and III (L2/3) cortical neurons in response to Sema3A was mediated by the activation of Rab5, a small guanosine triphosphatase (GTPase) that mediates endocytosis, through the membrane fusion protein Rabaptin-5 and the Rab5 guanine nucleotide exchange factor (GEF) Rabex-5. Rabaptin-5 bound directly to Plexin-A1 in the Sema3A receptor complex [an obligate heterodimer formed by Plexin-A1 and neuropilin 1 (NP1)]; Sema3A enhanced this interaction in cultured neurons. Rabaptin-5 bridged the interaction between Rab5 and Plexin-A1. Sema3A stimulated endocytosis from the cell surface of callosal axon growth cones. In utero electroporation to reduce Rab5 or Rabaptin-5 impaired axon fasciculation or caused mistargeting of L2/3 callosal projections in rats. Overexpression of Rabaptin-5 or Rab5 rescued the defective callosal axon fasciculation or mistargeting of callosal axons caused by the loss of Sema3A-Plexin-A1 signaling in rats expressing dominant-negative Plexin-A1 or in NP1-deficient mice. Thus, our findings suggest that Rab5, its effector Rabaptin-5, and its regulator Rabex-5 mediate Sema3A-induced axon guidance during brain development.
The analytical expressions for the cross-spectral density and average intensity of Gaussian Schell-model (GSM) vortex beams propagating through oceanic turbulence are obtained by using the extended Huygens-Fresnel principle and the spatial power spectrum of the refractive index of ocean water. The evolution behavior of GSM vortex beams through oceanic turbulence is studied in detail by numerical simulation. It is shown that the evolution behavior of coherent vortices and average intensity depends on the oceanic turbulence including the rate of dissipation of turbulent kinetic energy per unit mass of fluid, rate of dissipation of mean-square temperature, relative strength of temperature salinity fluctuations, and beam parameters including the spatial correlation length and topological charge of the beams, as well as the propagation distance.
Osteonecrosis of the femoral head is a severely disabling complication of steroid immunosuppression in renal transplant patients. The increased number of patients undergoing transplantation has increased the number of transplant recipients undergoing total hip replacement arthroplasty (THRA). In this study, we retrospectively assessed patients who underwent THRA from May 2004 to February 2014, and evaluated their demographic and clinical characteristics, the results of peri-operative laboratory tests, the amounts of fluids transfused during surgery, and anesthesia time. Our results found that post-operative acute kidney injury (AKI) was significantly associated with transplantation, and transplantation was an independent factor predictive of post-operative AKI, so transplant recipients are at risk for AKI following THRA. Total hip replacement is a safe and effective treatment for transplant recipients and, in view of their limited life expectancy, should be considered at an early stage in their treatment.
The 'third pole' of the world is a fitting metaphor for the Himalayan-Tibetan Plateau, in allusion to its vast frozen terrain, rivalling the Arctic and Antarctic, at high altitude but low latitude. Living Tibetan and arctic mammals share adaptations to freezing temperatures such as long and thick winter fur in arctic muskox and Tibetan yak, and for carnivorans, a more predatory niche. Here, we report, to our knowledge, the first evolutionary link between an Early Pliocene (3.60-5.08 Myr ago) fox, Vulpes qiuzhudingi new species, from the Himalaya (Zanda Basin) and Kunlun Mountain (Kunlun Pass Basin) and the modern arctic fox Vulpes lagopus in the polar region. A highly hypercarnivorous dentition of the new fox bears a striking resemblance to that of V. lagopus and substantially predates the previous oldest records of the arctic fox by 3-4 Myr. The low latitude, high-altitude Tibetan Plateau is separated from the nearest modern arctic fox geographical range by at least 2000 km. The apparent connection between an ancestral high-elevation species and its modern polar descendant is consistent with our 'Out-of-Tibet' hypothesis postulating that high-altitude Tibet was a training ground for cold-environment adaptations well before the start of the Ice Age.
Bovine serum albumin (BSA) nanoparticle is a promising drug carrier system. Oridonin (ORI)-loaded galactosylated BSA nanoparticle (ORI-GB-NP) was prepared for liver targeting delivery of ORI. This work was designed to investigate the in vitro release, in vivo pharmacokinetics and tissue distribution of ORI-GB-NP. ORI-GB-NP was prepared by the desolvation method. The particle size of ORI-GB-NP was 172.0?±?8.3?nm with narrow size distribution. The in vitro release of ORI-GB-NP exhibited biphasic drug release pattern with an initial burst release and consequently sustained release. Pharmacokinetic analysis displayed that ORI-GB-NP and ORI-loaded BSA nanoparticle (ORI-BSA-NP) could enhance the drug plasma level and prolong the circulation time in contrast with ORI solution. Meanwhile, compared with ORI-BSA-NP, ORI-GB-NP could deliver more ORI to liver and simultaneously reduce the toxicity of ORI to heart, lung and kidney. In conclusion, ORI-GB-NP could be a promising drug delivery system for liver cancer therapy.
Regulatory T-cells (Tregs) are responsible for homeostasis of the immune system, as well as for inhibition of pathogenic autoimmune processes. Induced-(i)-Tregs, can be generated in vitro by activation of CD4 cells in the presence of TGF-?. A commonly used activation mechanism is by antibodies against CD3 and CD28. The physiological-like activation of T-cells, however, is with the specific target antigen presented by antigen-presenting cells (APC). The two modes of activation have been considered to yield the same populations of iTregs. Here, we compared between iTreg populations generated by either one of the two methods and found differences between their capacities to inhibit T-lymphocyte proliferative response, their expression of cell surface antigens and particularly, in their transcript expression profiles of certain chemokines and chemokine receptors. Our data thus indicate that iTregs generated by activation with anti-CD3/CD28 antibodies cannot be considered identical to iTregs generated by antigen/APC.
Rho GTPases, acting as molecular switches, are involved in the regulation of diverse cellular functions. Rho GTPase activating proteins (Rho GAPs) function as negative regulators of Rho GTPases and are required for a variety of signaling processes in cell development. But the mechanisms underlying Rho GAPs in Rho-mediated signaling pathways in fungi are still elusive. There are eight RhoGAP domain-containing genes annotated in the Magnaporthe oryzae genome. To understand the function of these RhoGAP genes, we generated knockout mutants of each of the RhoGAP genes through a homologous recombination-based method. Phenotypic analysis showed that growth rate of aerial hyphae of the Molrg1 deletion mutant decreased dramatically. The ?Molrg1 mutant showed significantly reduced conidiation and appressorium formation by germ tubes. Moreover, it lost pathogenicity completely. Deletion of another Rho GAP (MoRga1) resulted in high percentage of larger or gherkin-shaped conidia and slight decrease in conidiation. Appressorial formation of the ?MoRga1 mutant was delayed significantly on hydrophobic surface, while the development of mycelial growth and pathogenicity in plants was not affected. Confocal fluorescence microscopy imaging showed that MoRga1-GFP localizes to septal pore of the conidium, and this localization pattern requires both LIM and RhoGAP domains. Furthermore, either deleting the LIM or RhoGAP domain or introducing an inactivating R1032A mutation in the RhoGAP domain of MoRga1 caused similar defects as the Morga1 deletion mutant in terms of conidial morphology and appressorial formation, suggesting that MoRga1 is a stage-specific regulator of conidial differentiation by regulating some specific Rho GTPases. In this regard, MoRga1 and MoLrg1 physically interacted with both MoRac1-CA and MoCdc42-CA in the yeast two-hybrid and pull-down assays, suggesting that the actions of these two GAPs are involved in MoRac1 and MoCdc42 pathways. On the other hand, six other putative Rho GAPs (MoRga2 to MoRga7) were dispensable for conidiation, vegetative growth, appressorial formation and pathogenicity, suggesting that these Rho GAPs function redundantly during fungal development. Taking together, Rho GAP genes play important roles in M. oryzae development and infectious processes through coordination and modulation of Rho GTPases.
Plant LRR-RLKs serve as protein interaction platforms, and as regulatory modules of protein activation. Here, we report the isolation of a novel plant-specific LRR-RLK from Glycine soja (termed GsLRPK) by differential screening. GsLRPK expression was cold-inducible and shows Ser/Thr protein kinase activity. Subcellular localization studies using GFP fusion protein indicated that GsLRPK is localized in the plasma membrane. Real-time PCR analysis indicated that temperature, salt, drought, and ABA treatment can alter GsLRPK gene transcription in G. soja. However, just protein induced by cold stress not by salinity and ABA treatment in tobacco was found to possess kinase activity. Furthermore, we found that overexpression of GsLRPK in yeast and Arabidopsis can enhance resistance to cold stress and increase the expression of a number of cold responsive gene markers.
A liver-targeting drug delivery system for doxorubicin (DOX), that is, DOX-loaded self-assembled nanoparticles based on galactosylated O-carboxymethyl chitosan-graft-stearic acid conjugates (Gal-OS/DOX), has been prepared. The objective of the present study was to investigate the preparation, in vitro release, in vivo pharmacokinetics, and tissue distribution of Gal-OS/DOX nanoparticles. The drug-loaded nanoparticles were spherical in shape with mean size of 181.9 nm. In vitro release profiles indicated that the release of DOX from Gal-OS/DOX nanoparticles behaved with a sustained and pH-dependent drug release. Pharmacokinetics study revealed Gal-OS/DOX nanoparticles exhibited a higher AUC value and a prolonged residence time of drug in the blood circulation than those of DOX solution. Furthermore, Gal-OS/DOX nanoparticles increased the uptake of DOX in liver and spleen, but decreased uptake in heart, lung, and kidney in the tissue distribution study. These results suggested that the Gal-OS/DOX nanoparticles could prolong blood circulation time, enhance the liver accumulation, and reduce the side effect especially the cardiotoxicity of DOX. In conclusion, Gal-OS/DOX nanoparticles could be a promising drug delivery system for liver cancer therapy.
T-helper (Th) lineages have been generated in vitro by activating CD4 cells with anti-CD3/CD28 antibodies during polarization. Physiologically, however, the generation of Th lineages is by activation with the specific antigen presented by antigen-presenting cells (APC). Here, we used T-cell receptor (TCR)-transgenic mice to compare the phenotypes of Th1, Th9 and Th17 lineages when generated by either one of the two activation modes. Lineage Th cells specific against hen egg lysozyme (HEL), were adoptively transferred into recipient mice transgenically expressing HEL in their lens. Remarkable differences were found between lineages of Th1, Th9 or Th17, generated by either one of the two modes in their capacities to migrate to and proliferate in the recipient spleen and, importantly, to induce inflammation in the recipient mouse eyes. Substantial differences were also observed between the lineage pairs in their transcript expression profiles of certain chemokines and chemokine receptors. Surprisingly, however, close similarities were observed between the transcript expression profiles of lineages of the three phenotypes, activated by the same mode. Furthermore, Th cell lineages generated by the two activation modes differed considerably in their pattern of gene expression, as monitored by microarray analysis, but exhibited commonality with lineages of other phenotypes generated by the same activation mode. This study thus shows that (i) Th lineages generated by activation with anti-CD3/CD28 antibodies differ from lineages generated by antigen/APC; and (ii) the mode of activation determines to a large extent the expression profile of major transcripts.
Pantherine felids (big cats) include the largest living cats, apex predators in their respective ecosystems. They are also the earliest diverging living cat lineage, and thus are important for understanding the evolution of all subsequent felid groups. Although the oldest pantherine fossils occur in Africa, molecular phylogenies point to Asia as their region of origin. This paradox cannot be reconciled using current knowledge, mainly because early big cat fossils are exceedingly rare and fragmentary. Here, we report the discovery of a fossil pantherine from the Tibetan Himalaya, with an age of Late Miocene-Early Pliocene, replacing African records as the oldest pantherine. A total evidence phylogenetic analysis of pantherines indicates that the new cat is closely related to the snow leopard and exhibits intermediate characteristics on the evolutionary line to the largest cats. Historical biogeographic models provide robust support for the Asian origin of pantherines. The combined analyses indicate that 75% of the divergence events in the pantherine lineage extended back to the Miocene, up to 7 Myr earlier than previously estimated. The deeper evolutionary origin of big cats revealed by the new fossils and analyses indicate a close association between Tibetan Plateau uplift and diversification of the earliest living cats.
Ligands for aryl hydrocarbon receptor (AHR), such as dioxins, are highly toxic. One such ligand, TCDD, was found to exert potent immunosuppressive capacities in mice developing pathogenic autoimmune processes, including EAU, but its toxicity makes it unusable for humans. A recently identified endogenous AHR ligand, ITE, is also immunosuppressive, but is nontoxic and could therefore be useful for therapy in humans. Here, we tested ITE for its capacity to inhibit EAU and related immune responses.
A novel polymer, i.e. galactosylated O-carboxymethyl chitosan-graft-stearic acid (Gal-OCMC-g-SA) was synthesized for liver targeting delivery of doxorubicin. The chemical structure was characterized by FT-IR, (1)H NMR and elemental analysis. Gal-OCMC-g-SA could self-assemble into nanoparticles with diameter of 160 nm by probe sonication in aqueous medium and exhibited a low critical aggregation concentration of 0.047 mg/mL. The DOX-loaded Gal-OCMC-g-SA (Gal-OCMC-g-SA/DOX) self-assembled nanoparticles were almost spherical in shape with an average diameter of less than 200 nm and zeta potential of around -10 mV. In vitro release revealed that the Gal-OCMC-g-SA/DOX nanoparticles exhibited a sustained and pH-dependent drug release manner. Furthermore, the hemolysis test demonstrated the good safety of Gal-OCMC-g-SA in blood-contacting applications. These results indicated that Gal-OCMC-g-SA/DOX nanoparticles were highly potential to be applied in cancer therapy.
Oridonin (ORI), a diterpenoid compound with promising antitumor activity, was proved to possess potent antileukemia efficacies in vitro and in vivo recently. However, the development and application of ORI was limited by its poor solubility and rapid plasma clearance. The purpose of this study was to solve these problems. PEGylated oridonin linked with succinic acid (SA) as spacer moiety (PEG-SA-ORI conjugate) was synthesized. mPEG amines with four specifications of molecular weight (MW) were utilized. All polymeric conjugates showed satisfactory aqueous solubility and in vitro studies implied that the drug solubility and release features of conjugates were relevant to PEGs. The drug solubility increased more when the MW of PEG was lower, while more significant sustained-release effect was shown with higher PEG MW. Moreover, the release behaviors of conjugates showed a pH-sensitive property. In vivo pharmacokinetic studies demonstrated that the elimination half-life was prolonged in comparison with ORI solution. PEGylation could be a promising method to obtain better efficacy in the field of drug delivery system.
The interaction between TLRs and their cognate ligands triggers both the innate and adaptive immune systems, and thus can play a pivotal role in the defense against pathogen invasion. This work investigates the differentiation of naive CD4 cells into Th1 or Th17 phenotypes in mice treated with different TLR ligands. We use a model system in which naive transgenic cells specific to hen egg lysozyme are adoptively transferred into recipients that express hen egg lysozyme in the lens of the eye. The transferred naive T cells induce ocular inflammation only in recipients treated with TLR ligands. Treatment with LPS preferentially stimulated IL-17 production, whereas CpG oligodeoxynucleotide and polyinosinic:polycytidylic acid primarily stimulated Th1 cells. Peptidoglycan stimulated the two Th subpopulations equally. The preferential induction of Th1 or Th17 by the four ligands was detected in the spleen (where a major portion of the adoptively transferred cells homed) and in the eyes, where activated Th cells initiate inflammation. Analysis of the cytokines present in recipient mice suggests that Th1 induction is elicited by IL-12 and/or IFN-?, whereas Th17 generation is preferentially mediated by IL-6. Importantly, we show in this article that treatment with LPS selectively promoted in the recipient mice the generation of IL-6-producing activated B cells. An inverse correlation was found between the level of regulatory T cells and severity of inflammation induced by the donor cells. Taken together, our data show that specific TLR ligands differentially activate the immune system as evidenced by the generation of distinct Th phenotypes from naive CD4 cells.
A rice protein homologous to eukaryotic translation elongation factor 1A (eEF-1A) was found to interact with the Pns6 of rice ragged stunt virus (RRSV), the type member of the genus Oryzavirus, family Reoviridae, in yeast two-hybrid screening. The interaction between the rice protein, designated OseEF-1A, and RRSV Pns6 was confirmed by bimolecular fluorescence complementation. Besides Pns6, OseEF-1A also interacted with the viroplasm matrix protein, Pns10, of RRSV. When expressed together, OseEF-1A co-localized with RRSV Pns10 in epidermal cells of Nicotiana benthamiana. Pns6 of southern rice black-streaked dwarf virus (SRBSDV), a newly reported member of the genus Fijivirus, family Reoviridae, was the only non-structural SRBSDV protein studied here that also interacted with OseEF-1A. Like Pns6 of rice black-streaked dwarf virus (RBSDV), SRBSDV Pns6 interacted with itself and co-localized with Pns9-1 in N. benthamiana. In the presence of Pns6, OseEF-1A co-localized with Pns9-1, the putative viroplasm matrix protein of SRBSDV.
The EZH2 gene, which is expressed in various solid tumours, including liver cancer, can regulate gene transcription and promote the generation and progression of tumours. Our aim was to investigate the relationship between EZH2 and multidrug-resistance of human hepatic cancer cells using RNA interference.
Recently, nanosuspension technology has evolved into a mature drug delivery system, which can enhance the saturation solubility and dissolution velocity of poorly soluble drugs. In this study, nanosuspensions of a p-terphenyl derivative (H2) were prepared by combining microfluidization and precipitation method and transformed into dry powder by lyophilization. The resultant nanosuspensions had a mean particle size of 201.7±5.87nm and a zeta potential of -21.07±0.57mV. The X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) analysis verified that the crystalline state of H2 was not transformed when it was prepared to nanosuspensions. An increased saturation solubility (1.46ug/ml) and accelerated dissolution velocity were achieved. The percent drug release of bulk H2 and H2 nanosuspension dried powder was 7.16% and 93.5% at 120min point, respectively. The pharmacokinetic test in rats indicated that the area under plasma concentration-time curve (AUC0~?) value of H2 nanosuspension (5.183mg/Lh) was about 5-fold higher than that of H2 solution (1.094mg/Lh). Additionally, the mean retention time (MRT) value of H2 nanosuspension (2.832h) was significantly longer than that of H2 solution (0.997h).
In this study, galactosylated bovine serum albumin (GB), which could be developed for a liver targeting carrier was synthetized and it was identified by Fourier transform infrared (FT-IR) spectrometer. Oridonin loaded bovine serum albumin nanoparticle (ORI-BSA-NP) and oridonin loaded GB nanoparticle (ORI-GB-NP) were prepared and optimized by the desolvation technique. During the preparation of ORI-GB-NP, galactosamine was introduced to end-cap the free aldehyde groups on nanoparticles. The characteristics of ORI-GB-NP such as particle size, zeta potential, particle morphologie, entrapment efficiency and drug loading were evaluated. The nearly spherical nanoparticles, with a narrow size distribution below 200 nm, were negatively charged with zeta potential of about -30 mV. Meanwhile, differential scanning calorimetry (DSC) and X-ray diffraction confirmed the amorphous state of ORI in ORI-GB-NP. The in vitro drug release of ORI from ORI-GB-NP presented a biphasic pattern with an initial burst effect and consequently sustained release. These results implied that the nanoparticles possessed fine physicochemical characteristics and seemed to be a stable delivery system for poorly soluble oridonin.
In the present study, mesoporous silica nanoparticles (MSNs) with three pore size were manufactured by the etch method. A typical chemotherapeutic agent, paclitaxel (PTX) was loaded into these MSNs. The in vitro drug release behavior, the in vitro anti-tumor activity, the morphological apoptosis cell changes, cell apoptosis rate and pharmacokinetics were extensively evaluated to clarify the biomedical roles of these MSNs in the application of drug delivery. The results showed that paclitaxel-loaded MSNs not only demonstrated effective drug loading but also exhibited pore-size-dependent drug release performance in vitro. In addition, MSNs exhibited pore-size-dependent anti-tumor activity against breast cancer MCF-7 cells. The apoptosis mechanism study demonstrated that the percentage of early and late apoptosis of all PTX-loaded MSNs treated MCF-7 cells were significantly higher than that of free PTX, and additionally the percentage of apoptosis for PTX-loaded MSNs increased as the pore size of carriers enlarged. The pharmacokinetics results showed that PTX-loaded MSNs with the largest pore size exhibited the pharmacokinetic property similar to the PTX solution and the other drug loaded MSNs displayed sustained release behavior. These results demonstrate that MSNs could be a very promising drug delivery system for pore-size controllable drug release and enhancing the anti-tumor activity.
Autophagy is an evolutionarily conserved membrane trafficking process. Induction of autophagy in response to nutrient limitation or cellular stress occurs by similar mechanisms in organisms from yeast to mammals. Unlike yeast, metazoan cells rely more on growth factor signaling for a wide variety of cellular activities including nutrient uptake. How growth factor availability regulates autophagy is poorly understood. Here we show that, upon growth factor limitation, the p110? catalytic subunit of the class IA phosphoinositide 3-kinases (PI3Ks) dissociates from growth factor receptor complexes and increases its interaction with the small GTPase Rab5. This p110?-Rab5 association maintains Rab5 in its guanosine triphosphate (GTP)-bound state and enhances the Rab5-Vps34 interaction that promotes autophagy. p110? mutants that fail to interact with Rab5 are defective in autophagy promotion. Hence, in mammalian cells, p110? acts as a molecular sensor for growth factor availability and induces autophagy by activating a Rab5-mediated signaling cascade.
Processing of ?-amyloid precursor protein (APP) by ?- and ?-secretases in neurons produces amyloid-? (A?), whose excess accumulation leads to Alzheimers disease (AD). Knowledge on subcellular trafficking pathways of APP and its fragments is important for the understanding of AD pathogenesis. We designed fusion proteins comprising a C-terminal fragment of APP (app) and fluorescent proteins GFP (G) and DsRed (D) to permit the tracking of the fusion proteins and fragments in cells. CAD cells expressing these proteins emitted colocalized green and red fluorescence and produce ectodomains, sGapp and sRapp, and A?, whose level was reduced by inhibitors of ?- and ?-secretases. The presence of GappR in endosomes was observed via colocalization with Rab5. These observations indicated that the fusion proteins were membrane inserted, transported in vesicles and proteolytically processed by the same mechanism for APP. By attenuating fusion protein synthesis with cycloheximide, individual fluorescent colors from the C-terminus of the fusion proteins appeared in the cytosol which was strongly suppressed by ?-secretase inhibitor, suggesting that the ectodomains exit the cell rapidly (t1/2 about 20min) while the C-terminal fragments were retained longer in cells. In live cells, we observed the fluorescence of the ectodomains located between parental fusion proteins and plasma membrane, suggesting that these ectodomain positions are part of their secretion pathway. Our results indicate that the native ectodomain does not play a decisive role for the key features of APP trafficking and processing and the new fusion proteins may lead to novel insights in intracellular activities of APP.
A shortage of Cenozoic vertebrate fossils in the Tibetan Plateau has been an obstacle in our understanding of biological evolution in response to changes in tectonism, topography, and environment. This is especially true for Paleogene records, so far known by only two sites along the northern rim of the Plateau. We report a Hongyazi Basin in northern Tibetan Plateau that produces at least three mammalian faunas that span Oligocene through late Miocene. Located at the foothills of the Danghe Nanshan and presently connected to the northern margin of the Suganhu Basin through the Greater Haltang River, the intermountain basin is controlled by the tectonics of the Danghe Nanshan to the north and Chahanebotu Mountain to the south, making the basin sediments well suited for inferring the evolutionary history of these two mountain ranges. At the bottom of the local section, the Oligocene Haltang Fauna is best compared to the early Oligocene Desmatolagus-Karakoromys decessus assemblage in the Dingdanggou Fauna in Tabenbuluk Basin. The Middle Miocene Ebotu Fauna from the middle Hongyazi section shares many taxa with the late Middle Miocene Tunggur mammal assemblage in Inner Mongolia, such as Heterosminthus orientalis, Megacricetodon sinensis, Democricetodon lindsayi, and Alloptox gobiensis. Toward the top of the section, the Hongyazi Fauna includes late Miocene elements typical of Hipparion faunas of North China. All three faunas are of typical North China-Central Asian characteristics, suggesting a lack of geographic barriers for faunal differentiation through the late Miocene. Sedimentary packages producing these faunas are arrayed from north to south in progressively younger strata, consistent with a compressive regime to accommodate shortening between Danghe Nanshan and Chahanebotu Mountain by thrust faults and folds. With additional constraints from vertebrate fossils along the northern flanks of the Danghe Nanshan, an eastward propagation of the Danghe Nanshan is postulated.
It is reported that the nanosuspension is one of the promising formulations for poorly water-soluble drugs. In order to enhance the in vitro and in vivo behaviours of DDB (bifendate), DDB-NSP (DDB nanosuspensions) have been produced by the precipitation-combined micro?uidization method. The optimized DDB-NSP were transformed into dry powders by freeze-drying and then investigated by transmission electron microscopy, laser diffraction and X-ray diffraction (XRD) experiments. Next, the pharmacokinetics and biodistribution of DDB-NSP and DDB-Sol (DDB solution) were carried out. XRD experiments manifested that the crystalline state of DDB was preserved after the size reduction process. An accelerated dissolution velocity and increased saturation solubility could be shown for the DDB-NSP. Compared with DDB-Sol, DDB-NSP exhibited a markedly different pharmacokinetic property with a 17.18-fold increase in AUC(0-?). Meanwhile, the tissue distribution demonstrated that DDB-NSP were mainly uptaken by RES organs particularly by liver. These results supported the fact that nanosuspension, as a promising intravenous drug-delivery system for DDB, could be developed as an alternative to the conventional DDB preparations.
Nanogels based on the polymers of galactosylated chitosan-graft-poly (N-isopropylacrylamide) (Gal-CS-g-PNIPAm) were used as carriers of oridonin (ORI) for tumor targeting. Three ORI-loaded nanogels with various degrees of galactose substitution were prepared, and their characteristics were evaluated. The release behavior of ORI from these nanogels was pH-dependent, and the release could be accelerated under mildly acidic conditions. The cytotoxicity of ORI-loaded nanogels was pH-sensitive. ORI-loaded nanogels exhibited a higher antitumor activity than drug-loaded nanogels without galactosylation, and the anticancer activity increased in relation to increases in the number of galactose moieties of the nanogels in HepG2 cells. In contrast, the cytotoxicity of ORI-loaded nanogels against MCF-7 cells decreased compared with that of drug-loaded nanogels without galactosylation. Results demonstrated that these nanogels could enhance the uptake of ORI into HepG2 cells via asialoglycoprotein receptor-mediated endocytosis. These galactose-decorated pH-responsive nanogels were well-suited for targeted drug delivery to liver cancer cells.
Riccardin D is a new compound extracted from liverwort Marchantia polymorpha L. It has been proved to be useful in antifungal therapy and reversing the resistance of Candida albicans against fluconazole. However, the poor solubility leads to the poor bioavailability and limits its development. In this study, nanocrystals were prepared in the evaporative precipitation into aqueous solution (EPAS) and the microfluidisation process. The characterizations of nanocrystals were compared by transmission electron microscope, size distribution, and zeta potential. In the EPAS method, the drug was dissolved in the organic phase and F68, HPMC, PVP K30 were dissolved in water with the mass ratio of 2:1:2:1. In the microfluidisation process, two key factors - pressure and number of cycles were screened and 8 cycles at 2000 bar was the most efficient parameter. The nanocrystals made in EPAS process were smaller, more uniform and had a narrower distribution than the microfluidisation nanocrystals. Differential scanning calorimetry (DSC) and X-ray diffraction confirmed the crystalline states that were both reserved. The solubility was greatly improved by the two methods and the EPAS nanocrystals were more soluble due to the smaller size. An enhanced dissolution was obvious in vitro. And the stable nanocrystals were successfully achieved by the two methods.
Ice Age megafauna have long been known to be associated with global cooling during the Pleistocene, and their adaptations to cold environments, such as large body size, long hair, and snow-sweeping structures, are best exemplified by the woolly mammoths and woolly rhinos. These traits were assumed to have evolved as a response to the ice sheet expansion. We report a new Pliocene mammal assemblage from a high-altitude basin in the western Himalayas, including a primitive woolly rhino. These new Tibetan fossils suggest that some megaherbivores first evolved in Tibet before the beginning of the Ice Age. The cold winters in high Tibet served as a habituation ground for the megaherbivores, which became preadapted for the Ice Age, successfully expanding to the Eurasian mammoth steppe.
Rab22 is a small GTPase that is localized on early endosomes and regulates early endosomal sorting. This study reports that Rab22 promotes nerve growth factor (NGF) signaling-dependent neurite outgrowth and gene expression in PC12 cells by sorting NGF and the activated/phosphorylated receptor (pTrkA) into signaling endosomes to sustain signal transduction in the cell. NGF binding induces the endocytosis of pTrkA into Rab22-containing endosomes. Knockdown of Rab22 via small hairpin RNA (shRNA) blocks NGF-induced pTrkA endocytosis into the endosomes and gene expression (VGF) and neurite outgrowth. Overexpression of human Rab22 can rescue the inhibitory effects of the Rab22 shRNA, suggesting a specific Rab22 function in NGF signal transduction, rather than off-target effects. Furthermore, the Rab22 effector, Rabex-5, is necessary for NGF-induced neurite outgrowth and gene expression, as evidenced by the inhibitory effect of shRNA-mediated knockdown of Rabex-5. Disruption of the Rab22-Rabex-5 interaction via overexpression of the Rab22-binding domain of Rabex-5 in the cell also blocks NGF-induced neurite outgrowth, suggesting a critical role of Rab22-Rabex-5 interaction in the biogenesis of NGF-signaling endosomes to sustain the signal for neurite outgrowth. These data provide the first evidence for an early endosomal Rab GTPase as a positive regulator of NGF signal transduction and cell differentiation.
Multidrug resistance (MDR) in tumor cells is a significant obstacle for successful cancer chemotherapy. Overexpression of drug efflux transporters such as P-glycoprotein (P-gp) is a key factor contributing to the development of tumor drug resistance. Verapamil (VRP), a P-gp inhibitor, has been reported to be able to reverse completely the resistance caused by P-gp. For optimal synergy, the drug and inhibitor combination may need to be temporally colocalized in the tumor cells. Herein, we investigated the effectiveness of simultaneous and targeted delivery of anticancer drug, paclitaxel (PTX), along with VRP, using DOMC-FA micelles to overcome tumor drug resistance. The floate-functionalized dual agent loaded micelles resulted in the similar cytotoxicity to PTX-loaded micelles/free VRP combination and co-administration of two single-agent loaded micelles, which was higher than that of PTX-loaded micelles. Enhanced therapeutic efficacy of dual agent micelles could be ascribe to increased accumulation of PTX in drug-resistant tumor cells. We suggest that the synergistic effect of folate receptor-mediated internalization and VRP-mediated overcoming MDR could be beneficial in treatment of MDR solid tumors by targeting delivery of micellar PTX into tumor cells. As a result, the difunctional micelle systems is a very promising approach to overcome tumor drug resistance.
Th1 cells are remarkably more susceptible to activation induced cell death than Th17. Here, we compared cultures of these two cell subpopulations for their expression of apoptosis-related molecules when re-exposed to their specific antigen. We also compared the expression of apoptosis-related molecules in the mouse eye with inflammation induced by Th1 or Th17 cells. Using qPCR we found that the mRNA transcript levels of the majority of tested apoptosis-related molecules were higher in the Th1 cultures, and in eyes with Th1-induced inflammation. Apoptotic intrinsic pathway molecules played minor roles in the processes in vitro or in vivo, whereas extrinsic pathway molecules, as well as PD-1, its ligands and Tim3, were heavily involved.
The present study aims to evaluate the antitumor activity of silybin nanosuspension on human prostatic carcinoma PC-3 cell line in vitro. Silybin nanosuspension was prepared by the high pressure homogenization (HPH) method. MTT assay, observation of morphological changes and apoptotic body showed that silybin nanosuspension could significantly enhance the in vitro cytotoxicity against PC-3 cells compared to the silybin solution. Flow cytometric (FCM) analysis demonstrated that silybin nanosuspension induced G1 cycle arrest and apoptosis in PC-3 cells. Thereby, the overall results suggest that the silybin nanosuspension represents a potential source of medicine for the treatment of human prostate cancer.
The Rab family of GTPases contains over 60 genes in the human genome and contributes to regulation of intracellular membrane trafficking along endocytic and exocytic pathways as well as specialized pathways in specific cell types. It has become increasingly clear that disruption of the intracellular membrane trafficking system at different stages can cause various diseases. In the past decade, altered expression levels and mutations of Rab GTPases have been associated with such diseases as cancer, Alzheimers disease, and various genetic disorders. This review discusses the specific Rab GTPases and their involvement in the diseases.
Recently reported lines of Th9 cells, producing IL-9 and IL-10, were generated by polarization with IL-4 and TGF-? and activation with Abs against CD3 and CD28. In this paper, we analyzed features of Th9 lines similarly polarized but activated by the "natural mode" (i.e., exposure of CD4 cells to their target Ag, hen egg lysozyme [HEL] and APCs). Main observations are the following: 1) both IL-9 and IL-10 were expressed by the line cells, but with strikingly different kinetics, with IL-9 being produced rapidly, reaching a peak on day 3 in culture and declining sharply thereafter, whereas IL-10 production increased gradually, resembling IL-4 and IL-17 production by their corresponding lineage cells; 2) reactivation of Th9, following expansion, triggered faster and higher production of both IL-9 and IL-10; 3) incubating Th9 cells in polarizing media specific for other phenotypes stimulated moderate levels of phenotype switching to Th1 or Th17 but a massive switching to Th2; 4) Th9 cells induced moderate inflammation in HEL-expressing recipient eyes but only when producing high levels of IL-9; and 5) IL-9-producing donor cells were detected in the blood of Th9 recipients but not in their inflamed eyes, suggesting that similar to findings in culture, exposure to HEL in these eyes arrested the IL-9 production in Th9 cells. Collectively, these data provide new information concerning Th9 cells and reveal their uniqueness, in particular with regard to the unusual production kinetics of IL-9 and the short retention of these cells in affected target tissues.
In this study, we evaluate the effect of particle sizes on the physicochemical properties of silybin and identify the influence of silybin nanosuspensions on its permeation across the Caco-2 cell monolayer. In vivo pharmacokinetic evaluation of silybin nanosuspensions was also carried out in beagle dogs. TEM, AFM and SEM analyses revealed the effect of homogenization pressure on particle size and morphology, and confirmed the existence of a surfactant-stabilizer film on the surface of nanoparticles. DSC and XRPD experiments manifested that the crystalline state was maintained as particle size was reduced and the enhanced dissolution property was due to the increased surface area. Nanosuspensions had a significant influence on drug transport across the Caco-2 cell monolayer and the enhanced dissolution velocity was responsible for the increased permeability. A pharmacokinetics study in beagle dogs further confirmed the in vitro results and demonstrated that oral administration of silybin nanosuspensions significantly increase its bioavailability compared to the coarse powder. Nanosuspensions of silybin with smaller particle size reveal a higher potential to increase their oral bioavailability; while for intravenous infusion the lower pressure produced silybin nanosuspensions appeared to maintain a more sustained drug release profile.
Rabex-5 is a guanine nucleotide exchange factor (GEF) that specifically activates Rab5, i.e., converting Rab5-GDP to Rab5-GTP, through two distinct pathways to promote endosome fusion and endocytosis. The direct pathway involves a pool of membrane-associated Rabex-5 that targets to the membrane via an early endosomal targeting (EET) domain. The indirect pathway, on the other hand, involves a cytosolic pool of Rabex-5/Rabaptin-5 complex. The complex is recruited to the membrane via Rabaptin-5 binding to Rab5-GTP, suggesting a positive feedback mechanism. The relationship of these two pathways for Rab5 activation in the cell is unclear.
Both Th1 and Th17 T cell subsets can mediate inflammation, but the kinetics of the pathogenic processes mediated by these two subsets have not been investigated. Using an experimental system in which TCR-transgenic Th1 or Th17 cells specific for hen egg lysozyme induce ocular inflammation in recipient mice expressing eye-restricted hen egg lysozyme, we found important differences in the in vivo behavior of these two subsets. Th1 cells initially proliferated considerably faster and invaded the eye more quickly than their Th17 counterparts, but then disappeared rapidly. By contrast, Th17 cells accumulated and remained the majority of the infiltrating CD4(+) cells in the eye for as long as 25 days after transfer, mediating more long-lasting pathological changes. Unlike Th1, Th17 cells were highly resistant to restimulation-induced apoptosis, a major pathway by which autoimmune and chronically restimulated Th1 cells are eliminated. Th17 cells had reduced Fas ligand production and resistance to Fas-induced apoptosis, relative to Th1 cells, despite similar surface expression of Fas. Th17-induced ocular inflammation also differed from Th1-induced inflammation by consisting of more neutrophils, whereas Th1-induced disease had higher proportions of CD8 cells. Taken together, our data show that pathogenic processes triggered by Th17 lag behind those induced by Th1, but then persist remarkably longer, apparently due to the relative resistance of Th17 cells to restimulation-induced cell death. The long-lasting inflammation induced by Th17 cells is in accord with these cells being involved in chronic conditions in humans.
Rabex-5 targets to early endosomes and functions as a guanine nucleotide exchange factor for Rab5. Membrane targeting is critical for Rabex-5 to activate Rab5 on early endosomes in the cell. Here, we report the identification of Rab22 as a binding site on early endosomes for direct recruitment of Rabex-5 and activation of Rab5, establishing a Rab22-Rab5 signaling relay to promote early endosome fusion. Rab22 in guanosine 5-O-(3-thio)triphosphate-loaded form, but not guanosine diphosphate-loaded form, binds to the early endosomal targeting domain (residues 81-230) of Rabex-5 in pull-down assays. Rabex-5 targets to Rab22-containing early endosomes, and Rab22 knockdown by short hairpin RNA abrogates the membrane targeting of Rabex-5 in the cell. In addition, coexpression of Rab22 and Rab5 shows synergistic enlargement of early endosomes, and this synergy is dependent on Rabex-5, providing further support for the collaboration of the two Rab GTPases in regulation of endosome dynamics. This novel Rab22-Rabex-5-Rab5 cascade is functionally important for the endocytosis and degradation of epidermal growth factor.
Eukaryotic lanthionine synthetase C-like protein 1 (LanCL1) is homologous to prokaryotic lanthionine cyclases, yet its biochemical functions remain elusive. We report the crystal structures of human LanCL1, both free of and complexed with glutathione, revealing glutathione binding to a zinc ion at the putative active site formed by conserved GxxG motifs. We also demonstrate by in vitro affinity analysis that LanCL1 binds specifically to the SH3 domain of a signaling protein, Eps8. Importantly, expression of LanCL1 mutants defective in Eps8 interaction inhibits nerve growth factor (NGF)-induced neurite outgrowth, providing evidence for the biological significance of this novel interaction in cellular signaling and differentiation.
In the title compound, C(18)H(20)N(2)O(3), the two phenyl rings, adopt opposite orientations in the backbone and are oriented at a dihedral angle of 36.66?(3)°. In the crystal, inter-molecular C-H?O inter-actions link the mol-ecules into a three-dimensional network.
Riccardin D (RD) is a novel compound extracted from Chinese liverwort Marchantia polymorpha L. It exhibits various anticancer activities and can be used during lung cancer treatment. However, the compounds low solubility hinders its development. Recently nanosuspension has been developed as one of the most promising formulations for poorly water-soluble drugs. In order to understand the dissolution behavior of riccardin D in vitro and in vivo, two nanosuspensions of riccardin D with markedly different sizes were prepared. The particle size of nanosuspension A prepared by bottom-up method was 184.1±3.15 nm, while that of nanosuspension B prepared by top-down method was 815.4±9.65 nm. The main purpose of this study was to investigate the effects of particle size on pharmacokinetics and tissue distribution after intravenous administration. Riccardin D dissolving in organic solution was studied as control group. In pharmacokinetics study in Wistar rats, nanosuspension A showed properties similar to the control group, while nanosuspension B exhibited rather different properties. In tissue distribution research on Kunming strain mice, nanosuspension A had a multi-peak phenomenon because of reticulate endothelial system (RES) while nanosuspension B showed a high uptake in RES organs that passively target to the lungs. In conclusion, particle size of riccardin D nanosuspensions had obvious effects on pharmacokinetics and tissue distribution.
A novel approach was applied to fabricate mesoporous silica nanoparticles (MSNs) with different pore size in this study. The pore size of MSNs can be modulated conveniently from 3 nm to 10nm by controlling the etching time of MSNs with the NaBH(4) solution. The as-synthesized MSNs were investigated as carriers for loading and delivery of the model drug paclitaxel (PTX). The characteristics, drug loading capacity, in vitro drug release behavior, anti-tumor activity and the mechanism of cell uptake were systematically studies. The resultant MSNs showed uniform and mono-dispersed sphere with high drug loading capacity (12-21%). The in vitro drug release exhibited that the released rate of PTX from MSNs could be controlled by the pore size and the larger the pore size, the faster the release rate of PTX. The in vitro anti-tumor studies demonstrated that PTX-loaded MSNs produced higher cytotoxicity than free PTX. Besides, the PTX-loaded MSNs with largest pore size showed the highest anti-tumor activity. These results indicated that these MSNs could provide a promising platform for delivering water-insoluble drugs, controlling the release rate of drugs and increasing the anti-tumor activity.
SWAP 70-like adaptor of T cells (SLAT; aka Def6) is a recently discovered guanine nucleotide exchange factor for Rho guanosine triphosphate (GTP)ases that has been previously shown to play a role in cluster of differentiation(CD)4+ T cell activation, T-helper (Th)1/Th2/Th17 differentiation and development of experimental autoimmune encephalomyelitis. Here, we investigated the role of SLAT/Def6 in the development of experimental autoimmune uveitis (EAU), an animal model for several uveitic conditions in humans.
Subpopulations of pathogenic or nonpathogenic Th17 cells were reported to develop when presensitized CD4 cells were activated with their target Ag during polarization by either IL-23 or IL-6 and TGF-?, respectively. In this study, we generated two Th17 subpopulations by using a system in which naive CD4 cells from TCR transgenic mice specific to hen egg lysozyme (HEL) are polarized with IL-6/TGF-? and, concurrently, are activated either with HEL presented by APCs, or with anti-CD3/CD28 Abs. Only the former cells were pathogenic, inducing inflammation in eyes expressing HEL. Naive CD4 cells activated by the anti-CD3/CD28 Abs acquired pathogenicity, however, when cocultured with HEL/APC. Importantly, the naive CD4 cells did not acquire pathogenicity when cocultured with APCs stimulated with LPS or when separated from the HEL-presenting cells by a semipermeable membrane. Unlike with presensitized Th17, soluble IL-23 does not participate in pathogenicity acquisition by naive CD4 cells; no pathogenicity was induced by adding IL-23 to cultures activated with anti-CD3/CD28 Abs. Furthermore, Abs against IL-23 or IL-23R did not inhibit acquisition of pathogenicity in cultures of naive CD4 cells activated by HEL/APC. Our data thus show that, unlike presensitized CD4 cells, naive CD4 cells polarized toward Th17 phenotype acquire pathogenicity only by direct interaction with APCs presenting the Ag, with no apparent involvement of soluble IL-23. We suggest that the Th17 lymphocytes derived from naive CD4 cells participate in pathogenic and other immune processes, along with the IL-23-dependent Th17 cells.
In this study, oridonin-loaded nanoparticles coated with galactosylated chitosan (ORI-GC-NP) were prepared for tumor targeting and their characteristics were evaluated for the morphologies, particle size and zeta potential. Oridonin-loaded nanoparticles (ORI-NP) without galactosylated chitosan were prepared as a control. The entrapment efficiency of ORI-GC-NP and ORI-NP were 72.15% and 85.31%, respectively. The in vitro drug release behavior from nanoparticles displayed biphasic drug release pattern with initial burst release and consequently sustained release. Next, the pharmacokinetics and tissue distribution of ORI-GC-NP, ORI-NP and ORI solution were carried out. Pharmacokinetic analysis showed that ORI-GC-NP and ORI-NP could prolong the drug plasma levels compared with ORI solution. Meanwhile, the distribution of ORI-GC-NP to liver was higher than that of ORI-NP and free drug. In conclusion, ORI-GC-NP, as a promising intravenous drug delivery system for ORI, could be developed as an alternative to the conventional ORI preparations.
Epidermal growth factor (EGF), latrophilin and seven transmembrane domain-containing protein 1 (ELTD1) is developmentally upregulated in the heart. Little is known about the relationship between ELTD1 and cardiac diseases. Therefore, we aimed to clarify the role of ELTD1 in pressure overload-induced cardiac hypertrophy.
The Tibetan Plateau is the youngest and highest plateau on Earth, and its elevation reaches one-third of the height of the troposphere, with profound dynamic and thermal effects on atmospheric circulation and climate. The uplift of the Tibetan Plateau was an important factor of global climate change during the late Cenozoic and strongly influenced the development of the Asian monsoon system. However, there have been heated debates about the history and process of Tibetan Plateau uplift, especially the paleo-altimetry in different geological ages. Here we report a well-preserved skeleton of a 4.6 million-y-old three-toed horse (Hipparion zandaense) from the Zanda Basin, southwestern Tibet. Morphological features indicate that H. zandaense was a cursorial horse that lived in alpine steppe habitats. Because this open landscape would be situated above the timberline on the steep southern margin of the Tibetan Plateau, the elevation of the Zanda Basin at 4.6 Ma was estimated to be ?4,000 m above sea level using an adjustment to the paleo-temperature in the middle Pliocene, as well as comparison with modern vegetation vertical zones. Thus, we conclude that the southwestern Tibetan Plateau achieved the present-day elevation in the mid-Pliocene.
The purpose of this study was to develop poly(ethylene glycol)-coated nanostructured lipid carriers (PEG-NLC) for parenteral delivery of oridonin (ORI) to prolong drug circulation time in blood. Oridonin-loaded PEG-NLC (ORI-PEG-NLC) consisting of PEG(2000)-stearate, glycerol monostearate and medium chain triglycerides were prepared by emulsion-evaporation and low temperature-solidification technique. Oridonin-loaded NLC (ORI-NLC) were also prepared as control. ORI-PEG-NLC were observed by transmission election microscope and the morphology was in rotiform shape. The mean particle size of ORI-PEG-NLC was 329.2 nm and entrapment efficacy was 71.18%. The results of differential scanning calorimetry and X-ray diffraction revealed a low-crystalline structure of ORI and verified the incorporation of ORI into the nanoparticles. In vitro drug release of ORI-PEG-NLC exhibited biphasic drug release patterns with burst release initially and prolonged release afterwards. Pharmacokinetic analysis showed that the mean residence time of ORI-PEG-NLC was prolonged and AUC (area under tissue concentration-time curve) value was also improved compared with ORI-NLC and ORI solution. In conclusion, ORI-PEG-NLC could be a potential carrier to get prolonged retention time of oridonin in blood.
A critical disadvantage for successful chemotherapy with paclitaxel (PTX) is its nontargeting nature to cancer cells. Folic acid has been employed as a targeting ligand of various anticancer agents to increase their cellular uptake within target cells since the folate receptor is overexpressed on the surface of such tumor cells. In this study, a novel biodegradable deoxycholic acid-O-carboxymethylated chitosan-folic acid conjugate (DOMC-FA) was used to form micelles for encapsulating the anticancer drug PTX.
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