PRMT5 Promotes T follicular helper Cell Differentiation and Germinal Center Responses during Influenza Virus Infection.

Protein arginine methyltransferases (PRMTs) modify diverse protein targets and regulate numerous cellular processes; yet, their contributions to individual effector T cell responses during infections are incompletely understood. In this study, we identify PRMT5 as a critical regulator of CD4+ T follicular helper cell (Tfh) responses during influenza virus infection in mice. Conditional PRMT5 deletion in murine T cells results in an almost complete ablation of both Tfh and T follicular regulatory populations and, consequently, reduced B cell activation and influenza-specific Ab production. Supporting a potential mechanism, we observe elevated surface expression of IL-2Rα on non-T regulatory effector PRMT5-deficient T cells. Notably, IL-2 signaling is known to negatively impact Tfh differentiation. Collectively, our findings identify PRMT5 as a prominent regulator of Tfh programming, with potential causal links to IL-2 signaling.

How to Advise Medical Students Interested in Dermatology: A Survey of Academic Dermatology Mentors.

Dermatology residency programs are among the most competitive residencies of medical specialties. To navigate this competitive process, students seek advice from dermatology mentors who provide a range of responses depending on their experience or preferences. To consolidate this range of advice, we surveyed members of the Association of Professors of Dermatology (APD) on their responses to common questions from medical students regarding quantity of program applications, research gap year, internship year, letters of intent, away rotations, letters of recommendation (LORs), and the new Electronic Residency Application Service (ERAS) supplemental application. Although recommendations given to students remain individualized, our study describes the range of advice received and details the differences between mentor advice and common student practices throughout the application cycle. We hope these data will help mentors in advising students as well as inform organizations seeking to create standards and official recommendations regarding aspects of the application process.

Re-examination of MAGE-A3 as a T-cell Therapeutic Target.

In 2013, an innovative MAGE-A3-directed cancer therapeutic of great potential value was terminated in the clinic because of neurotoxicity. The safety problems were hypothesized to originate from off-target T-cell receptor activity against a closely related MAGE-A12 peptide. A combination of published and new data led us to test this hypothesis with current technology. Our results call into question MAGE-A12 as the source of the neurotoxicity. Rather, the data imply that an alternative related peptide from EPS8L2 may be responsible. Given the qualities of MAGE-A3 as an onco-testis antigen widely expressed in tumors and largely absent from normal adult tissues, these findings suggest that MAGE-A3 may deserve further consideration as a cancer target. As a step in this direction, the authors isolated 2 MAGE-A3 peptide-major histocompatibility complex-directed chimeric antigen receptors, 1 targeting the same peptide as the clinical T-cell receptor. Both chimeric antigen receptors have improved selectivity over the EPS8L2 peptide that represents a significant risk for MAGE-A3-targeted therapeutics, showing that there may be other options for MAGE-A3 cell therapy.

Free-Floating Bikeshare and Helmet Use in Seattle, WA.

Wearing a helmet when bicycling prevents traumatic brain injury in the event of a crash. Most cyclists nationwide use helmets when riding. However, the growth of free-floating bike sharing systems, which offer short-term access to bicycles but not helmets, may erode helmet-wearing norms among cyclists. We counted cyclists over several hours at four locations in Seattle, WA. We categorized each rider according to whether he or she was wearing a helmet and to whether or not he or she was riding a bike share bike. Whereas 91% of riders of private bikes wore helmets, only 20% of bike share riders wore helmets. Moreover, in locations where a greater proportion of riders were on bikes hare bikes, fewer riders of private bicycles wore helmets (r = - 0.96, p = 0.04). The impact of bike sharing programs on helmet wearing norms among private bike riders warrants further exploration.

Autoimmune Th2-mediated dacryoadenitis in MRL/MpJ mice becomes Th1-mediated in IL-4 deficient MRL/MpJ mice.

PURPOSE: MRL/MpJ mice of substrains MRL/MpJ-fas(+)/fas(+) (MRL/+) and MRL/MpJ-fas(lpr)/fas(lpr) (MRL/lpr) spontaneously develop autoimmune dacryoadenitis and sialadenitis and are a model for the human disorder Sjögren syndrome. The dacryoadenitis in both substrains appears to be Th2 in nature, with little IFN-gamma and substantial IL-4 at the site of lacrimal gland inflammation. METHODS: MRL/MpJ mice with a defective IL-4 gene-both MRL/+-IL-4(tm)/IL-4(tm) (MRL/+/IL-4(tm)) and MRL/lpr-IL-4(tm)/IL-4(tm) (MRL/lpr-IL-4(tm))-that resulted in a loss of IL-4 production were bred and evaluated for dacryoadenitis. RESULTS: MRL/+/IL-4(tm) and MRL/lpr/IL-4(tm) mice developed dacryoadenitis of similar onset, appearance, and severity as found in MRL/MpJ mice with an intact IL-4 gene. Immunohistochemistry examination revealed a substantially greater number of inflammatory cells staining for IFN-gamma than for IL-13 in the dacryoadenitis of IL-4-deficient MRL/MpJ mice (MRL/+/IL-4(tm), 66% vs. 0.8%, P = 0.001; MRL/lpr/IL-4(tm), 67% vs. 1.2%, P = 0.002). Real-time PCR demonstrated greater amounts of IFN-gamma than IL-13 mRNA relative transcripts in lacrimal glands of MRL/lpr/IL-4(tm) mice (mean difference, 28.6; P = 0.035). Greater CD86 (B7-2) than CD80 (B7-1) expression was present in MRL/+/IL-4(tm) mice (11% vs. 3%, P = 0.003) and MRL/lpr/IL-4(tm) mice (10% vs. 3%, P = 0.002). CONCLUSIONS: These results suggest that a Th2 autoimmune process can be converted to a Th1 process in the absence of IL-4.

Inflammatory mediators in autoimmune lacrimal gland disease in MRL/Mpj mice.

PURPOSE: MRL/MpJ-fas(+)/fas(+) (MRL/+) and MRL/MpJ-fas(lpr)/fas(lpr) (MRL/lpr) mice are congenic substrains of mice that have spontaneously developing lacrimal and salivary gland inflammation and are models for the human disorder Sjögren's syndrome. Nitric oxide (NO) and tumor necrosis factor (TNF)-alpha are proinflammatory and potential mediators of tissue damage. The presence of the inducible form of nitric oxide synthase (iNOS), which catalyzes the production of NO, and the presence TNF-alpha in the lacrimal glands of MRL/MpJ mice were assessed. METHODS: Lacrimal glands from MRL/+ and MRL/lpr mice, at ages 1 through 9 months, were evaluated by real-time RT-PCR for iNOS and TNF-alpha mRNA and by immunohistochemistry for the presence of iNOS and of TNF-alpha. Age-matched BALB/c lacrimal glands were used as the control. RESULTS: By quantitative real-time PCR (qPCR), mRNA for iNOS was detected in the lacrimal glands in significantly greater amounts in both MRL/+ (median, normalized to 18S rRNA, 2.90; P < 0.0003) and MRL/lpr mice (median 6.84, P < 0.001) than in BALB/c mice (median 0.34). By qPCR, mRNA for TNF-alpha in the lacrimal glands was detected in significantly greater amounts in aged MRL/+ mice than in BALB/c mice (median, normalized to actin, 221.8 vs. 77.8, P = 0.011) and in MRL/lpr mice than in BALB/c mice (median 136.7 vs. 72.5, P = 0.001). Immunohistochemistry demonstrated both iNOS and TNF-alpha in scattered mononuclear cells throughout the lacrimal glands and in mononuclear cells at the junction of the focal inflammatory infiltrates and normal acinar tissue in both MRL/+ and MRL/lpr mice. CONCLUSIONS: As demonstrated by the greater presence of iNOS and TNF-alpha in the lacrimal glands of MRL/MpJ mice than in control glands, both NO and TNF-alpha are potential mediators of lacrimal gland damage in these murine models of Sjögren's syndrome.

Chemokines in autoimmune lacrimal gland disease in MRL/MpJ mice.

PURPOSE: MRL/MpJ-fas+/fas+ (MRL/+) and MRL/MpJ-fas(lpr)/fas(lpr) (MRL/lpr) mice undergo spontaneous development of inflammation of the lacrimal and salivary glands, similar to that in the human disorder Sjögren's syndrome. Previous work has shown that these lesions appear to be largely T helper (Th)-2-driven, as evidenced by the substantially greater expression of IL-4 than interferon-gamma. The relative contributions of selected chemokines associated with Th1 and Th2 immune responses were assessed. METHODS: Lacrimal glands from MRL/+ and MRL/lpr mice, at ages 1.5 through 9 months were evaluated by immunohistochemistry for the chemokines monocyte chemoattractant protein (MCP)-1 (also known as chemokine ligand [CCL]-2), MCP-5 (CCL12), thymus activation regulated chemokine (TARC; or CCL17), and macrophage-derived chemokine (MDC; or CCL22). Additional lacrimal glands were tested by real-time RT-PCR for chemokines MCP-1 and -5, which are associated with Th2 and Th1 responses, respectively. RESULTS: By immunohistochemistry a significantly greater proportion of mononuclear inflammatory cells in the lacrimal gland lesions stained for MCP-1 (29%-48% depending on age) compared with MCP-5 (1%-3% depending on age) both in MRL/+ (mean difference 34.2%, P < 0.001) and MRL/lpr (mean difference 33.6%, P < 0.001) substrains. Real-time RT-PCR studies showed higher transcript levels of MCP-1 compared with MCP-5, in both MRL/+ (median difference, 37.3; P < 0.0001) and MRL/lpr (median difference, 77.1; P < 0.0001) mice. Relative transcripts of MCP-1 increased with age in both MRL/+ mice (P = 0.02) and MRL/lpr mice (P = 0.03). Staining for TARC was present on lacrimal gland ductular cells but not on the infiltrating lymphocytes, and staining for MDC was present on scattered individual cells throughout the lacrimal gland, but not on infiltrating lymphocytes. CONCLUSIONS: The predominant expression of a Th2-associated chemokine in the lacrimal gland lesions in this murine model of Sjögren's syndrome may contribute to the predominantly Th2-type lymphoid infiltrate in these tissues.