Traumatic brain injury (TBI) provokes inflammatory responses, including a dramatic rise in brain macrophages in the area of injury. The pathway(s) responsible for macrophage infiltration of the traumatically injured brain and the effects of macrophages on functional outcomes are not well understood. C-C-chemokine receptor 2 (CCR2) is known for directing monocytes to inflamed tissues. To assess the role of macrophages and CCR2 in TBI, we determined outcomes in CCR2-deficient (Ccr2(-/-)) mice in a controlled cortical impact model. We quantified brain myeloid cell numbers post-TBI by flow cytometry and found that Ccr2(-/-) mice had greatly reduced macrophage numbers (?80-90% reduction) early post-TBI, compared with wild-type mice. Motor, locomotor, and cognitive outcomes were assessed. Lack of Ccr2 improved locomotor activity with less hyperactivity in open field testing, but did not affect anxiety levels or motor coordination on the rotarod three weeks after TBI. Importantly, Ccr2(-/-) mice demonstrated greater spatial learning and memory, compared with wild-type mice eight weeks after TBI. Although there was no difference in the volume of tissue loss, Ccr2(-/-) mice had significantly increased neuronal density in the CA1-CA3 regions of the hippocampus after TBI, compared with wild-type mice. These data demonstrate that Ccr2 directs the majority of macrophage homing to the brain early after TBI and indicates that Ccr2 may facilitate harmful responses. Lack of Ccr2 improves functional recovery and neuronal survival. These results suggest that therapeutic blockade of CCR2-dependent responses may improve outcomes following TBI.
Music has pain-relieving effects, but its mechanisms remain unclear. We sought to verify previously studied analgesic components and further elucidate the underpinnings of music analgesia. Using a well-characterized conditioning-enhanced placebo model, we examined whether boosting expectations would enhance or interfere with analgesia from strongly preferred music. A two-session experiment was performed with 48 healthy, pain experiment-naïve participants. In a first cohort, 36 were randomized into 3 treatment groups, including music enhanced with positive expectancy, non-musical sound enhanced with positive expectancy, and no expectancy enhancement. A separate replication cohort of 12 participants received only expectancy-enhanced music following the main experiment to verify the results of expectancy-manipulation on music. Primary outcome measures included the change in subjective pain ratings to calibrated experimental noxious heat stimuli, as well as changes in treatment expectations. Without conditioning, expectations were strongly in favor of music compared to non-musical sound. While measured expectations were enhanced by conditioning, this failed to affect either music or sound analgesia significantly. Strongly preferred music on its own was as pain relieving as conditioning-enhanced strongly preferred music, and more analgesic than enhanced sound. Our results demonstrate the pain-relieving power of personal music even over enhanced expectations.
Serine/threonine kinase 31 (STK31) is one of the novel cancer/testis antigens for which its biological functions remain largely unclear. Here, we demonstrate that STK31 is overexpressed in many human colorectal cancer cell lines and tissues. STK31 co-localizes with pericentrin in the centrosomal region throughout all phases of the cell cycle. Interestingly, when cells undergo mitosis, STK31 also localizes to the centromeres, central spindle, and midbody. This localization behavior is similar to that of chromosomal passenger proteins, which are known to be the important players of the spindle assembly checkpoint. The expression of STK31 is cell cycle-dependent through the regulation of a putative D-box near its C-terminal region. Ectopically-expressed STK31-GFP increases cell migration and invasive ability without altering the proliferation rate of cancer cells, whereas the knockdown expression of endogenous STK31 by lentivirus-derived shRNA results in microtubule assembly defects that prolong the duration of mitosis and lead to apoptosis. Taken together, our results suggest that the aberrant expression of STK31 contributes to tumorigenicity in somatic cancer cells. STK31 might therefore act as a potential therapeutic target in human somatic cancers.
Hypothermia is neuroprotective against many acute neurological insults, including ischemic stroke. We and others have previously shown that protection by hypothermia is partially associated with an anti-inflammatory effect. Phagocytes are thought to play an important role in the clearance of necrotic debris, paving the way for endogenous repair mechanisms to commence, but the effect of cooling and phagocytosis has not been extensively studied. Triggering receptor expressed on myeloid cells-2 (TREM2) is a newly identified surface receptor shown to be involved in phagocytosis. In this study, we examined the effect of therapeutic hypothermia on TREM2 expression. Mice underwent permanent middle cerebral artery occlusion (MCAO) and were treated with one of the two cooling paradigms: one where cooling (30°C) began at the onset of MCAO (early hypothermia [eHT]) and another where cooling began 1 hour later (delayed hypothermia [dHT]). In both groups, cooling was maintained for 2 hours. A third group was maintained at normothermia (NT) as a control (37°C). Mice from the NT and dHT groups had similar ischemic lesion sizes and neurological performance, but the eHT group showed marked protection as evidenced by a smaller lesion size and less neurological deficits up to 30 days after the insult. Microglia and macrophages increased after MCAO as early as 3 days, peaked at 7 days, and decreased by 14 days. Both hypothermia paradigms were associated with decreased numbers of microglia and macrophages at 3 and 7 days, with greater decreases in the early paradigm. However, the proportion of the TREM2-positive microglia/macrophages was actually increased among the eHT group at day 7. eHT showed a long-term neurological benefit, but neuroprotection did not correlate to immune suppression. However, hypothermic neuroprotection was associated with a relative increase in TREM2 expression, and suggests that TREM2 may serve a beneficial role in brain ischemia.
Traumatic brain injury (TBI) elicits innate inflammatory responses that can lead to secondary brain injury. To better understand the mechanisms involved in TBI-induced inflammation, we examined the nature of macrophages responding to TBI in mice. In this model, brain macrophages were increased >20-fold the day after injury and >77-fold 4 days after injury in the ipsilateral hemisphere compared with sham controls. TBI macrophage subsets were identified by using a reporter mouse strain (YARG) that expresses eYFP from an internal ribosome entry site (IRES) inserted at the 3 end of the gene for arginase-1 (Arg1), a hallmark of alternatively activated (M2) macrophages. One day after TBI, 21 ± 1.5% of ipsilateral brain macrophages expressed relatively high levels of Arg1 as detected by yellow fluorescent protein, and this subpopulation declined thereafter. Arg1(+) cells localized with macrophages near the TBI lesion. Gene expression analysis of sorted Arg1(+) and Arg1(-) brain macrophages revealed that both populations had profiles that included features of conventional M2 macrophages and classically activated (M1) macrophages. The Arg1(+) cells differed from Arg1(-) cells in multiple aspects, most notably in their chemokine repertoires. Thus, the macrophage response to TBI initially involves heterogeneous polarization toward at least two major subsets.
In lupus nephritis, glomerular injury correlates poorly with progression to renal failure. While the tubulointerstitium is also commonly involved, the importance of such involvement is not well defined. Therefore, we developed a simple method to assess the prognostic utility of measuring tubulointerstitial inflammation (TI).
The most prevalent severe manifestation of systemic lupus erythematosus is nephritis, which is characterized by immune complex deposition, inflammation, and scarring in glomeruli and the tubulointerstitium. Numerous studies indicated that glomerulonephritis results from a systemic break in B cell tolerance, resulting in the local deposition of immune complexes containing Abs reactive with ubiquitous self-Ags. However, the pathogenesis of systemic lupus erythematosus tubulointerstitial disease is not known. In this article, we demonstrate that in more than half of a cohort of 68 lupus nephritis biopsies, the tubulointerstitial infiltrate was organized into well-circumscribed T:B cell aggregates or germinal centers (GCs) containing follicular dendritic cells. Sampling of the in situ-expressed Ig repertoire revealed that both histological patterns were associated with intrarenal B cell clonal expansion and ongoing somatic hypermutation. However, in the GC histology, the proliferating cells were CD138(-)CD20(+) centroblasts, whereas they were CD138(+)CD20(low/-) plasmablasts in T:B aggregates. The presence of GCs or T:B aggregates was strongly associated with tubular basement membrane immune complexes. These data implicate tertiary lymphoid neogenesis in the pathogenesis of lupus tubulointerstitial inflammation.
There is growing recognition that students training to provide care for older adults need to be trained in all settings where older adults receive care, including retirement communities. The purpose of this study was to allow medical students to see older patients living and participating in activities in the long-term care setting and examine the effects that this experience had on the students.
Following neuronal injury, microglia initiate repair by phagocytosing dead neurons without eliciting inflammation. Prior evidence indicates triggering receptor expressed by myeloid cells-2 (TREM2) promotes phagocytosis and retards inflammation. However, evidence that microglia and neurons directly interact through TREM2 to orchestrate microglial function is lacking. We here demonstrate that TREM2 interacts with endogenous ligands on neurons. Staining with TREM2-Fc identified TREM2 ligands (TREM2-L) on Neuro2A cells and on cultured cortical and dopamine neurons. Apoptosis greatly increased the expression of TREM2-L. Furthermore, apoptotic neurons stimulated TREM2 signaling, and an anti-TREM2 mAb blocked stimulation. To examine the interaction between TREM2 and TREM2-L in phagocytosis, we studied BV2 microglial cells and their engulfment of apoptotic Neuro2A. One of our anti-TREM2 mAb, but not others, reduced engulfment, suggesting the presence of a functional site on TREM2 interacting with neurons. Further, Chinese hamster ovary cells transfected with TREM2 conferred phagocytic activity of neuronal cells demonstrating that TREM2 is both required and sufficient for competent uptake of apoptotic neuronal cells. Finally, while TREM2-L are expressed on neurons, TREM2 is not; in the brain, it is found on microglia. TREM2 and TREM2-L form a receptor-ligand pair connecting microglia with apoptotic neurons, directing removal of damaged cells to allow repair.
To determine the value of cell-bound complement activation products in combination with antinuclear antibody (ANA), anti-double-stranded DNA antibody (anti-dsDNA), and anti-mutated citrullinated vimentin antibody (anti-MCV) for the diagnosis of systemic lupus erythematosus (SLE).
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