JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Structural characterization of the pulmonary innate immune protein SPLUNC1 and identification of lipid ligands.
FASEB J.
PUBLISHED: 09-17-2014
Show Abstract
Hide Abstract
The short palate, lung and nasal epithelial clone 1 (SPLUNC1) protein is a member of the palate, lung, and nasal epithelium clone (PLUNC) family, also known as bactericidal/permeability-increasing (BPI) fold-containing protein, family A, member 1 (BPIFA1). SPLUNC1 is an abundant protein in human airways, but its function remains poorly understood. The lipid ligands of SPLUNC1 as well as other PLUNC family members are largely unknown, although some reports provide evidence that lipopolysaccharide (LPS) could be a lipid ligand. Unlike previous hypotheses, we found significant structural differences between SPLUNC1 and BPI. Recombinant SPLUNC1 produced in HEK 293 cells harbored several molecular species of sphingomyelin and phosphatidylcholine as its ligands. Significantly, in vitro lipid-binding studies failed to demonstrate interactions between SPLUNC1 and LPS, lipoteichoic acid, or polymyxin B. Instead, one of the major and most important pulmonary surfactant phospholipids, dipalmitoylphosphatidylcholine (DPPC), bound to SPLUNC1 with high affinity and specificity. We found that SPLUNC1 could be the first protein receptor for DPPC. These discoveries provide insight into the specific determinants governing the interaction between SPLUNC1 and lipids and also shed light on novel functions that SPLUNC1 and other PLUNC family members perform in host defense.-Ning, F., Wang, C., Berry, K. Z., Kandasamy, P., Liu, H., Murphy, R. C., Voelker, D. R., Nho, C. W., Pan, C.-H., Dai, S., Niu, L., Chu, H-W., Zhang, G. Structural characterization of the pulmonary innate immune protein SPLUNC1 and identification of lipid ligands.
Related JoVE Video
Structural basis of chronic beryllium disease: linking allergic hypersensitivity and autoimmunity.
Cell
PUBLISHED: 02-02-2014
Show Abstract
Hide Abstract
T-cell-mediated hypersensitivity to metal cations is common in humans. How the T cell antigen receptor (TCR) recognizes these cations bound to a major histocompatibility complex (MHC) protein and self-peptide is unknown. Individuals carrying the MHCII allele, HLA-DP2, are at risk for chronic beryllium disease (CBD), a debilitating inflammatory lung condition caused by the reaction of CD4 T cells to inhaled beryllium. Here, we show that the T cell ligand is created when a Be(2+) cation becomes buried in an HLA-DP2/peptide complex, where it is coordinated by both MHC and peptide acidic amino acids. Surprisingly, the TCR does not interact with the Be(2+) itself, but rather with surface changes induced by the firmly bound Be(2+) and an accompanying Na(+) cation. Thus, CBD, by creating a new antigen by indirectly modifying the structure of preexisting self MHC-peptide complex, lies on the border between allergic hypersensitivity and autoimmunity.
Related JoVE Video
T cell recognition of beryllium.
Curr. Opin. Immunol.
PUBLISHED: 07-25-2013
Show Abstract
Hide Abstract
Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by a hypersensitivity to beryllium and characterized by the accumulation of beryllium-specific CD4(+) T cells in the lung. Genetic susceptibility to beryllium-induced disease is strongly associated with HLA-DP alleles possessing a glutamic acid at the 69th position of the ?-chain (?Glu69). The structure of HLA-DP2, the most prevalent ?Glu69-containing molecule, revealed a unique solvent-exposed acidic pocket that includes ?Glu69 and represents the putative beryllium-binding site. The delineation of mimotopes and endogenous self-peptides that complete the ??TCR ligand for beryllium-specific CD4(+) T cells suggests a unique role of these peptides in metal ion coordination and the generation of altered self-peptides, blurring the distinction between hypersensitivity and autoimmunity.
Related JoVE Video
Structural basis of metal hypersensitivity.
Immunol. Res.
PUBLISHED: 06-14-2013
Show Abstract
Hide Abstract
Metal hypersensitivity is a common immune disorder. Human immune systems mount the allergic attacks on metal ions through skin contacts, lung inhalation and metal-containing artificial body implants. The consequences can be simple annoyances to life-threatening systemic illness. Allergic hyper-reactivities to nickel (Ni) and beryllium (Be) are the best-studied human metal hypersensitivities. Ni-contact dermatitis affects 10 % of the human population, whereas Be compounds are the culprits of chronic Be disease (CBD). ?? T cells (T cells) play a crucial role in these hypersensitivity reactions. Metal ions work as haptens and bind to the surface of major histocompatibility complex (MHC) and peptide complex. This modifies the binding surface of MHC and triggers the immune response of T cells. Metal-specific ?? T cell receptors (TCRs) are usually MHC restricted, especially MHC class II (MHCII) restricted. Numerous models have been proposed, yet the mechanisms and molecular basis of metal hypersensitivity remain elusive. Recently, we determined the crystal structures of the Ni and Be presenting human MHCII molecules, HLA-DR52c (DRA*0101, DRB3*0301) and HLA-DP2 (DPA1*0103, DPB1*0201). These structures revealed unusual features of MHCII molecules and shed light on how metal ions are recognized by T cells.
Related JoVE Video
Recognition of self and altered self by T cells in autoimmunity and allergy.
Protein Cell
PUBLISHED: 01-11-2013
Show Abstract
Hide Abstract
T cell recognition of foreign peptide antigen and tolerance to self peptides is key to the proper function of the immune system. Usually, in the thymus T cells that recognize self MHC + self peptides are deleted and those with the potential to recognize self MHC + foreign peptides are selected to mature. However there are exceptions to these rules. Autoimmunity and allergy are two of the most common immune diseases that can be related to recognition of self. Many genes work together to lead to autoimmunity. Of those, particular MHC alleles are the most strongly associated, reflecting the key importance of MHC presentation of self peptides in autoimmunity. T cells specific for combinations of self MHC and self peptides may escape thymus deletion, and thus be able to drive autoimmunity, for several reasons: the relevant self peptide may be presented at low abundance in the thymus but at high level in particular peripheral tissues; the relevant self peptide may bind to MHC in an unusual register, not present in the thymus but apparent elsewhere; finally the relevant self peptide may be post translationally modified in a tissue specific fashion. In some types of allergy, the peptide + MHC combination may also be fully derived from self. However the combination in question may be modified by the presence of other ligands, such as small drug molecules or metal ions. Thus these types of allergies may act like the post translationally modified peptides involved some types of autoimmunity.
Related JoVE Video
A single T cell receptor bound to major histocompatibility complex class I and class II glycoproteins reveals switchable TCR conformers.
Immunity
PUBLISHED: 03-01-2011
Show Abstract
Hide Abstract
Major histocompatibility complex class I (MHCI) and MHCII proteins differ in structure and sequence. To understand how T cell receptors (TCRs) can use the same set of variable regions to bind both proteins, we have presented a comparison of a single TCR bound to both MHCI and MHCII ligands. The TCR adopts similar orientations on both ligands with TCR amino acids thought to be evolutionarily conserved for MHC interaction occupying similar positions on the MHCI and MHCII helices. However, the TCR antigen-binding loops use different conformations when interacting with each ligand. Most importantly, we observed alternate TCR core conformations. When bound to MHCI, but not MHCII, V? disengages from the J? ? strand, switching V?s position relative to V?. In several other structures, either V? or V? undergoes this same modification. Thus, both TCR V-domains can switch among alternate conformations, perhaps extending their ability to react with different MHC-peptide ligands.
Related JoVE Video
Interaction of JMJD6 with single-stranded RNA.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 08-02-2010
Show Abstract
Hide Abstract
JMJD6 is a Jumonji C domain-containing hydroxylase. JMJD6 binds alpha-ketoglutarate and iron and has been characterized as either a histone arginine demethylase or U2AF65 lysyl hydroxylase. Here, we describe the structures of JMJD6 with and without alpha-ketoglutarate, which revealed a novel substrate binding groove and two positively charged surfaces. The structures also contain a stack of aromatic residues located near the active center. The side chain of one residue within this stack assumed different conformations in the two structures. Interestingly, JMJD6 bound efficiently to single-stranded RNA, but not to single-stranded DNA, double-stranded RNA, or double-stranded DNA. These structural features and truncation analysis of JMJD6 suggest that JMJD6 may bind and modify single-stand RNA rather than the previously reported peptide substrates.
Related JoVE Video
Mutation-specific control of BCR-ABL T315I positive leukemia with a recombinant yeast-based therapeutic vaccine in a murine model.
Vaccine
PUBLISHED: 06-28-2010
Show Abstract
Hide Abstract
Chromosomal translocations generating the BCR-ABL oncogene cause chronic myeloid leukemia (CML) and a subset of acute lymphoblastic leukemia. The BCR-ABL(T315I) mutation confers drug resistance to FDA-approved targeted therapeutics imatinib mesylate, dasatinib, and nilotinib. We tested the ability of a recombinant yeast-based vaccine expressing the T315I-mutated BCR-ABL antigen to stimulate an anti-BCR-ABL(T315I) immune response. The yeast-based immunotherapy significantly reduced or eliminated BCR-ABL(T315I) leukemia cells from the peripheral blood of immunized animals and extended leukemia-free survival in a murine model of BCR-ABL(+) leukemia compared to animals receiving sham injection or yeast expressing ovalbumin. With immunization, leukemic cells harboring BCR-ABL(T315I) were selectively eliminated after challenge with a mixed population of BCR-ABL and BCR-ABL(T315I) leukemias. In summary, yeast-based immunotherapy represents a novel approach against the emergence of cancer drug resistance by the pre-emptive targeted ablation of tumor escape mutants.
Related JoVE Video
Linking genetic susceptibility and T cell activation in beryllium-induced disease.
Proc Am Thorac Soc
PUBLISHED: 04-30-2010
Show Abstract
Hide Abstract
Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by beryllium (Be) exposure in the workplace. It is characterized by the accumulation of Be-specific CD4(+) T cells in the lung as well as persistent lung inflammation, culminating in the development of lung fibrosis. CBD occurs in 2 to 16% of Be-exposed workers depending on the individuals genetic susceptibility and the characteristics of the exposure. Genetic susceptibility to Be-induced disease has been linked to major histocompatibility complex class II molecules. In particular, HLA-DP alleles possessing a glutamic acid at the 69th position of the beta-chain (betaGlu69) are most strongly linked to disease susceptibility. The HLA-DP alleles that present Be to T cells match those implicated in the genetic susceptibility, suggesting that the HLA contribution to disease is based on the ability of those molecules to bind and present Be to T cells. However, the structural features of betaGlu69-containing HLA-DP molecules that explain the disease association remain unknown. We have recently crystallized HLA-DP2, which is the most prevalent of the betaGlu69-containing HLA-DP molecules. Its unique structure, which includes surface exposure of betaGlu69, provides an explanation of the genetic linkage between betaGlu69-containing HLA-DP alleles and Be-induced disease.
Related JoVE Video
Crystal structure of HLA-DP2 and implications for chronic beryllium disease.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 03-31-2010
Show Abstract
Hide Abstract
Chronic beryllium disease (CBD) is a fibrotic lung disorder caused by beryllium (Be) exposure and is characterized by granulomatous inflammation and the accumulation of Be-responsive CD4(+) T cells in the lung. Genetic susceptibility to CBD has been associated with certain alleles of the MHCII molecule HLA-DP, especially HLA-DPB1*0201 and other alleles that contain a glutamic acid residue at position 69 of the beta-chain (betaGlu69). The HLA-DP alleles that can present Be to T cells match those implicated in the genetic susceptibility, suggesting that the HLA contribution to disease is based on the ability of those molecules to bind and present Be to T cells. The structure of HLA-DP2 and its interaction with Be are unknown. Here, we present the HLA-DP2 structure with its antigen-binding groove occupied by a self-peptide derived from the HLA-DR alpha-chain. The most striking feature of the structure is an unusual solvent exposed acidic pocket formed between the peptide backbone and the HLA-DP2 beta-chain alpha-helix and containing three glutamic acids from the beta-chain, including betaGlu69. In the crystal packing, this pocket has been filled with the guanidinium group of an arginine from a neighboring molecule. This positively charged moiety forms an extensive H-bond/salt bridge network with the three glutamic acids, offering a plausible model for how Be-containing complexes might occupy this site. This idea is strengthened by the demonstration that mutation of any of the three glutamic acids in this pocket results in loss of the ability of DP2 to present Be to T cells.
Related JoVE Video
Many different Vbeta CDR3s can reveal the inherent MHC reactivity of germline-encoded TCR V regions.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 04-28-2009
Show Abstract
Hide Abstract
We have hypothesized that in the prenegative selection TCR repertoire, many somatically generated complementary-determining region (CDR) 3 loops combine with evolutionarily selected germline Valpha/Vbeta CDR1/CDR2 loops to create highly MHC/peptide cross-reactive T cells that are subsequently deleted by negative selection. Here, we present a mutational analysis of the Vbeta CDR3 of such a cross-reactive T-cell receptor (TCR), YAe62. Most YAe62 TCRs with the mutant CDR3s became less MHC promiscuous. However, others with CDR3s unrelated in sequence to the original recognized even more MHC alleles than the original TCR. Most importantly, this recognition was still dependent on the conserved CDR1/CDR2 residues. These results bolster the idea that germline TCR V elements are inherently reactive to MHC but that this reactivity is fine-tuned by the somatically generated CDR3 loops.
Related JoVE Video
T-cell receptor (TCR) interaction with peptides that mimic nickel offers insight into nickel contact allergy.
Proc. Natl. Acad. Sci. U.S.A.
Show Abstract
Hide Abstract
T cell-mediated allergy to Ni(++) is one of the most common forms of allergic contact dermatitis, but how the T-cell receptor (TCR) recognizes Ni(++) is unknown. We studied a TCR from an allergic patient that recognizes Ni(++) bound to the MHCII molecule DR52c containing an unknown self-peptide. We identified mimotope peptides that can replace both the self-peptide and Ni(++) in this ligand. They share a p7 lysine whose ?NH(2) group is surface-exposed when bound to DR52c. Whereas the TCR uses germ-line complementary-determining region (CDR)1/2 amino acids to dock in the conventional diagonal mode on the mimotope-DR52c complex, the interface is dominated by the TCR V? CDR3 interaction with the p7 lysine. Mutations in the TCR CDR loops have similar effects on the T-cell response to either the mimotope or Ni(++) ligand. We suggest that the mimotope p7 lysine mimics Ni(++) in the natural TCR ligand and that MHCII ?-chain flexibility in the area around the peptide p7 position forms a common site for cation binding in metal allergies.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.