Biology subjects

Ross, R. S.

Publications and source records attributed to Ross, R. S..

3 recordsLinked to original sources

bioRxiv2026

Regulation of Pacemaker Current in the Sinoatrial Node by Zonula Occludens-1

BACKGROUNDIn addition to lethal ventricular arrhythmias, arrhythmogenic cardiomyopathy (ACM) is associated with conduction abnormalities, bradycardias, and reduced expression of the scaffolding junctional protein zonula occludens-1 (ZO-1). Reduced ZO-1 expression is also seen in dilated cardiomyopathy, which is far more common than ACM. Conduction abnormalities are likewise a feature of ZO-1 cardiac-specific knockout (ZO-1cKO) mice. However, the role of ZO-1 in sinoatrial node (SAN) automaticity has not been studied. OBJECTIVETo investigate the role of ZO-1 in SAN automaticity and elucidate the mechanisms by which ZO-1 deficiency leads to SAN dysfunction. METHODSZO-1 cardiac-specific knockout (ZO-1cKO) mice were generated by crossing ZO-1 floxed mice with MHC-nuclear Cre mice. SAN/atrial tissue and isolated SAN cells were examined using optical mapping, single-cell patch clamp, and quantitative PCR techniques to assess functional alterations caused by ZO-1 loss. RESULTSZO-1cKO mice exhibited enlarged atria and SAN area compared to control mice, with normal left ventricular function. Electrocardiograms showed sinus bradycardia, sinus pauses and atrioventricular block. Optical mapping revealed a caudal shift in the SAN leading region and reduced intra-atrial conduction velocity in ZO-1cKO mice. Patch-clamp recordings from isolated SAN cells showed reduced spontaneous action potential frequency and diastolic depolarization rate, while voltage-clamp revealed a marked reduction in pacemaker current (If). CONCLUSIONZO-1 expression is essential for SAN automaticity. Its loss impairs SAN impulse generation by reducing pacemaker current and hampering atrial conduction, leading to bradyarrhythmia, conduction delay and block. These findings help explain impulse generation and conduction abnormalities in ACM and other cardiomyopathies.

physiology↗

bioRxiv2023

Surveillance of Vermont wildlife in 2021-2022 reveals no detected SARS-CoV-2 viral RNA

Previous studies have documented natural infections of SARS-CoV-2 in various domestic and wild animals. More recently, studies have been published noting the susceptibility of members of the Cervidae family, and infections in both wild and captive cervid populations. In this study, we investigated the presence of SARS-CoV-2 in mammalian wildlife within the state of Vermont. 739 nasal or throat samples were collected from wildlife throughout the state during the 2021 and 2022 harvest season. Data was collected from red and gray foxes (Vulpes vulples and Urocyon cineroargentus, respectively), fishers (Martes pennati), river otters (Lutra canadensis), coyotes (Canis lantrans), bobcats (Lynx rufus rufus), black bears (Ursus americanus), and white-tailed deer (Odocoileus virginianus). Samples were tested for the presence of SARS-CoV-2 via quantitative RT-qPCR using the CDC N1/N2 primer set and/or the WHO-E gene primer set. Our results indicate that no sampled wildlife were positive for SARS-CoV-2. This finding is surprising, given that most published North America studies have found SARS-CoV-2 within their deer populations. The absence of SARS-CoV-2 RNA in populations sampled here may provide insights in to the various environmental and anthropogenic factors that reduce spillover and spread in North Americans wildlife populations.

microbiology↗

bioRxiv2019

Context-dependent role of vinculin in neutrophil adhesion, motility and trafficking

Neutrophils are innate immune effector cells that traffic from the peripheral blood to extravascular sites of inflammation. {beta}2 integrins are involved during multiple phases of neutrophil recruitment, including the transition from rolling to arrest, firm attachment and motility within the vasculature. Following neutrophil arrest, adhesion stabilization occurs as the neutrophil interacts with the endothelial surface and crawls into a favorable position for extravasation. The cytoskeletal protein vinculin has been implicated in other cell types as a regulator of adhesion strength by promoting focal adhesion maturation and as a sensor of the mechanical properties of the microenvironment. Neutrophils express vinculin but do not form mature focal adhesions. Here, we characterize the role of vinculin in {beta}2 integrin-dependent neutrophil adhesion, motility, mechanosensing, and recruitment. We observe that knockout of vinculin attenuates, but does not completely abrogate, neutrophil adhesion, spreading, and crawling under static conditions. In the presence of forces from fluid flow, vinculin was not required for neutrophil adhesion or migration. Vinculin deficiency only mildly attenuated neutrophil traction stresses and spreading on stiff, but not soft, polyacrylamide gels indicating a minor role for vinculin in the mechanosensing of the neutrophil as compared to slower moving mesenchymal cells that form mature focal adhesions. Consistent with these findings, we observe in vivo neutrophil recruitment into the inflamed peritoneum of mice remains intact in the absence of vinculin. Together, these data suggest that while vinculin regulates some aspects of neutrophil adhesion and spreading, it may be dispensable for neutrophil recruitment and motility in vivo.

immunology↗