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The UMB Digital Archive is a service of the Health Sciences and Human Services Library (HS/HSL) that collects, preserves, and distributes the academic works of the University of Maryland, Baltimore. It is a place that digitally captures the historical record of the campus.
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MicroRNA410 Inhibits Pulmonary Vascular Remodeling via Regulation of Nicotinamide Phosphoribosyltransferase(Nature Publishing Group, 2019-07-09)Nicotinamide phosphoribosyltransferase (NAMPT) upregulation in human pulmonary artery endothelial cells (hPAECs) is associated with pulmonary arterial hypertension (PAH) progression and pulmonary vascular remodeling. The underlying mechanisms regulating NAMPT expression are still not clear. In this study, we aimed to study the regulation of NAMPT expression by microRNA410 (miR410) in hPAECs and explore the role of miR410 in the pathogenesis of experimental pulmonary hypertension. We show that miR410 targets the 3′ UTR of NAMPT and that, concomitant with NAMPT upregulation, miR410 is downregulated in lungs of mice exposed to hypoxia-induced pulmonary hypertension (HPH). Our results also demonstrate that miR410 directly inhibits NAMPT expression. Overexpression of miR410 in hPAECs inhibits basal and VEGF-induced proliferation, migration and promotes apoptosis of hPAECs, while miR410 inhibition via antagomirs has the opposite effect. Finally, administration of miR410 mimics in vivo attenuated induction of NAMPT in PAECs and prevented the development of HPH in mice. Our results highlight the role of miR410 in the regulation of NAMPT expression in hPAECs and show that miR410 plays a potential role in PAH pathobiology by targeting a modulator of pulmonary vascular remodeling. © 2019, The Author(s).
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Human cytomegalovirus evades antibody-mediated immunity through endoplasmic reticulum-associated degradation of the FcRn receptor(Nature Publishing Group, 2019-07-09)Human cytomegalovirus (HCMV) can persistently infect humans, but how HCMV avoids humoral immunity is not clear. The neonatal Fc receptor (FcRn) controls IgG transport from the mother to the fetus and prolongs IgG half-life. Here we show that US11 inhibits the assembly of FcRn with β2m and retains FcRn in the endoplasmic reticulum (ER), consequently blocking FcRn trafficking to the endosome. Furthermore, US11 recruits the ubiquitin enzymes Derlin-1, TMEM129 and UbE2J2 to engage FcRn, consequently initiating the dislocation of FcRn from the ER to the cytosol and facilitating its degradation. Importantly, US11 inhibits IgG-FcRn binding, resulting in a reduction of IgG transcytosis across intestinal or placental epithelial cells and IgG degradation in endothelial cells. Hence, these results identify the mechanism by which HCMV infection exploits an ER-associated degradation pathway through US11 to disable FcRn functions. These results have implications for vaccine development and immune surveillance. © 2019, The Author(s).
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Age-associated heterogeneity of Ty21A-induced T cell responses to HLA-E restricted Salmonella typhi antigen presentation(Frontiers Media S.A., 2019-01-01)Human-restricted Salmonella enterica serovar Typhi (S. Typhi) is the causative agent of typhoid fever-a life-threatening disease of great global health significance, particularly in the developing world. Ty21a is an oral live-attenuated vaccine that protects against the development of typhoid disease in part by inducing robust T cell responses, among which multifunctional CD8+ cytotoxic T lymphocytes (CTL) play an important role. Following Ty21a vaccination, a significant component of adult CTL have shown to be targeted to S. Typhi antigen presented by the conserved major histocompatibility complex (MHC) class Ib molecule, human leukocyte antigen-E (HLA-E). S. Typhi challenge studies have shown that baseline, multifunctional HLA-E responsive T cells are associated with protection from, and delayed onset of, typhoid disease. However, despite the overwhelming burden of typhoid fever in school-aged children, and due to limited availability of pediatric samples, incomplete information is available regarding these important HLA-E-restricted responses in children, even though studies have shown that younger children may be less likely to develop protective cell mediated immune (CMI) responses than adults following vaccination. To address this gap, we have studied this phenomenon in depth by using mass cytometry to analyze pediatric and adult T cell responses to HLA-E-restricted S. Typhi antigen presentation, before and after Ty21a vaccination. Herein, we show variable responses in all age strata following vaccination among T effector memory (TEM) and T effector memory CD45RA+ (TEMRA) cells based on conventional gating analysis. However, by utilizing the dimensionality reduction tool tSNE (t-distributed Stochastic Neighbor Embedding), we are able to identify diverse, highly multifunctional gut-homing- TEM and TEMRA clusters of cells which are more abundant in adult and older pediatric participants than in younger children. These findings highlight a potential age-associated maturation of otherwise conserved HLA-E restricted T cell responses. Such insights, coupled with the marked importance of multifunctional T cell responses to combat infection, may better inform future pediatric vaccination strategies against S. Typhi and other infectious diseases. Copyright © 2019 the authors.