Lin et al. explore the roles the chloride ion channel and transporters Clc-k1 and Clc-k2 in the thick ascending limb and renal medulla development. The cover image shows immunolabeled thick ascending limb of Henle’s loop from mouse kidney visualized using light-sheet fluorescent microscopy to detect sodium-potassium-chloride co-transporter type 2.
Understanding viral rebound in pediatric HIV-1 infection may inform the development of alternatives to lifelong antiretroviral therapy (ART) to achieve viral remission. We thus investigated viral rebound after analytical treatment interruption (ATI) in 10 infant macaques orally infected with SHIV.C.CH505 and treated with long-term ART. Rebound viremia was detected within 7-35 days of ATI in 9/10 animals, with post-treatment control of viremia seen in 5/5 Mamu-A*01+ macaques. Single-genome sequencing revealed initial rebound virus was similar to viral DNA present in CD4+ T cells from blood, rectum, and lymph nodes before ATI. We assessed the earliest sites of viral reactivation immediately following ATI using ImmunoPET imaging. The largest increase in signal that preceded detectable viral RNA in plasma was found in the gastrointestinal (GI) tract, a site with relatively high SHIV RNA/DNA ratios in CD4+ T cells prior to ATI. Thus, the GI tract may be an initial source of rebound virus but as ATI progresses, viral reactivation in other tissues likely contributes to the composition of plasma virus. Our study provides novel insight into the features of viral rebound in pediatric infection and highlights the application of a non-invasive technique to monitor areas of HIV-1 expression in children.
Veronica Obregon-Perko, Katherine M. Bricker, Gloria Mensah, Ferzan Uddin, Laura Rotolo, Daryll Vanover, Yesha Desai, Philip J. Santangelo, Sherrie Jean, Jennifer S. Wood, Fawn C. Connor-Stroud, Stephanie Ehnert, Stella J. Berendam, Shan Liang, Thomas H. Vanderford, Katharine J. Bar, George M. Shaw, Guido Silvestri, Amit Kumar, Genevieve G. Fouda, Sallie R. Permar, Ann Chahroudi
Point mutations within sarcomeric proteins have been associated with altered function and cardiomyopathy development. Difficulties remain, however, in establishing the pathogenic potential of individual mutations, often limiting the use of genotype in management of affected families. To directly address this challenge, we utilized our all-atom computational model of the human full cardiac thin filament (CTF) to predict how sequence substitutions in CTF proteins might affect structure and dynamics on an atomistic level.Utilizing molecular dynamics (MD) calculations, we simulated 21 well-defined genetic pathogenic cardiac troponin T and tropomyosin variants to establish a baseline of pathogenic changes induced in computational observables. Computational results were verified via differential scanning calorimetry on a subset of variants to develop an experimental correlation. Calculations were performed on 9 independent variants of unknown significance (VUS) and results were compared to pathogenic variants to identify high resolution pathogenic signatures.Results for VUS were compared to the baseline set to determine induced structural and dynamic changes and potential variant reclassifications were proposed. This unbiased, high- resolution computational methodology can provide unique structural and dynamic information that can be incorporated into existing analyses to facilitate classification both for de novo variants and those where established approaches have provided conflicting information.
Allison B. Mason, Melissa L. Lynn, Anthony P. Baldo, Andrea E. Deranek, Jil C. Tardiff, Steven D. Schwartz
Chronic inflammation and localized alterations in immune cell function are suspected to contribute to the progression of endometriosis and its associated symptoms. In particular, the alarmin, Interleukin (IL)-33 is elevated in the plasma, peritoneal fluid, and endometriotic lesions from endometriosis patients; however, the exact role of IL-33 in the pathophysiology of endometriosis is not well understood. In this study, we demonstrate, in both human patients and a murine model, that IL-33 contributes to the expansion of the novel group 2 innate lymphoid cells (ILC2s) and this IL-33 induced ILC2 expansion modulates the endometriosis lesion microenvironment. Importantly, we show that IL-33 drives hallmarks of severe endometriosis including elevated inflammation, lesion proliferation, and fibrosis and that this IL-33 induced aggravation is mediated by ILC2s. Finally, we demonstrate the functionality of IL-33 neutralization as a promising and novel therapeutic avenue for treating the debilitating symptoms of endometriosis.
Jessica E. Miller, Harshavardhan Lingegowda, Lindsey K. Symons, Olga Bougie, Steven L. Young, Bruce A. Lessey, Madhuri Koti, Chandrakant Tayade
In response to liver injury, hepatic stellate cells activate and acquire proliferative and contractile features. The regression of liver fibrosis appears to involve the clearance of activated hepatic stellate cells, either by apoptosis or by reversion towards a quiescent-like state, a process denominated deactivation. Thus, deactivation of active hepatic stellate cells has emerged as a novel and promising therapeutic approach for liver fibrosis. However, our knowledge of the master regulators involved in the de/activation of fibrotic hepatic stellate cells is still limited. The transcription factor GATA4 has been previously shown to play an important role in embryonic hepatic stellate cells quiescence. In this work, we show that lack of GATA4 in adult mice causes hepatic stellate cell activation and consequently, liver fibrosis. During regression of liver fibrosis, Gata4 is reexpressed in deactivated hepatic stellate cells. Overexpression of Gata4 in hepatic stellate cells promotes liver fibrosis regression in CCl4-treated mice. GATA4 induces changes in the expression of fibrogenic and antifibrogenic genes promoting hepatic stellate cell deactivation. Finally, we show that GATA4 directly represses EPAS1 transcription in hepatic stellate cells and that stabilization of the HIF2α protein in hepatic stellate cells leads to liver fibrosis.
Noelia Arroyo, Laura Villamayor, Irene Díaz, Rita Carmona, Mireia Ramos-Rodríguez, Ramon Muñoz-Chapuli, Lorenzo Pasquali, Miguel G. Toscano, Franz Martin, David A. Cano, Anabel Rojas
Glucagon-like peptide-1 receptor agonists (GLP-1RA) are used to treat diabetes and obesity and reduce rates of major cardiovascular events such as stroke and myocardial infarction. Nevertheless, the identity of GLP-1R-expressing cell types mediating the cardiovascular benefits of GLP-1RA remains incompletely characterized. Herein, we investigated the importance of murine Glp1r expression within endothelial and hematopoietic cells. Mice with targeted inactivation of the Glp1r in Tie2+ cells exhibited reduced levels of Glp1r mRNA transcripts in aorta, liver, spleen, blood and gut. Glp1r expression in bone marrow cells was very low, and not further reduced in Glp1rTie2-/- mice. The GLP-1RA semaglutide reduced the development of atherosclerosis induced by viral PCSK9 expression in both Glp1rTie2+/+ and Glp1rTie2-/- mice. Hepatic Glp1r mRNA transcripts were reduced in Glp1rTie2-/- mice and liver Glp1r expression was localized to γδ T cells. Moreover, semaglutide reduced hepatic Tnf, Abcg1, Tgfb1, Cd3g, Ccl2, and Il2 expression, triglyceride content and collagen accumulation in high fat high cholesterol (HFHC) diet-fed Glp1rTie2+/+ but not Glp1rTie2-/- mice. Collectively, these findings demonstrate that Tie2+ endothelial or hematopoietic cell GLP-1Rs are dispensable for the anti-atherogenic actions of GLP-1RA, whereas Tie2-targeted GLP-1R+ cells are required for a subset of the anti-inflammatory actions of semaglutide in the liver.
Brent McLean, Chi Kin Wong, Kiran Deep Kaur, Randy J. Seeley, Daniel J. Drucker
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