Biology subjects

Yucel, N.

Publications and source records attributed to Yucel, N..

4 recordsLinked to original sources

bioRxiv2025

ROR2 drives right ventricular heart failure via disruption of proteostasis

BackgroundNo therapies exist to reverse right ventricular failure (RVF), and the molecular mechanisms that drive RVF remain under studied. We recently reported that the developmentally restricted noncanonical WNT receptor ROR2 is upregulated in human RVF in proportion to severity of disease. Here we test the mechanistic role of ROR2 in RVF pathogenesis. MethodsROR2 was overexpressed or knocked down in neonatal rat ventricular myocytes (NRVMs) and then characterized using confocal microscopy, RNAseq, proteomics, proteostatic functional assays, and pacing to assess contractile properties. The impact of cardiac ROR2 expression was evaluated in mice by AAV9-mediated overexpression and by AAV9-mediated delivery of shRNA to knockdown ROR2 in a pulmonary artery banded pressure overload model of RVF. ROR2-modified mice were evaluated by echocardiography, histology, and RV protein synthesis and proteasome capacity. ResultsIn NRVMs, we find that ROR2 profoundly dysregulates the coordination between protein translation and folding. This imbalance leads to excess protein clearance by the ubiquitin proteasome system (UPS) with dramatic impacts on sarcomere and cytoskeletal structure and function. Inhibiting the UPS or restoring chaperone expression is sufficient to partially rescue ROR2-induced structural and contractile deficits in cardiomyocytes. In mice, forced cardiac ROR2 expression is sufficient to disrupt proteostasis and drive RVF, while conversely ROR2 knockdown partially rescues proteostasis and RV structure and function in a pressure overload model of RVF. ConclusionsIn sum, ROR2 is a key driver of RVF pathogenesis through proteostatic disruption and, thus, provides a promising target to treat RVF.

molecular biology↗

bioRxiv2022

Prediction and validation of host cleavage targets of SARS-CoV-2 3C like protease

How SARS-CoV-2 causes the observed range of clinical manifestations and disease severity remains poorly understood. SARS-CoV-2 encodes for two proteases (3CLPro and PLPro), vital for viral production, but also promiscuous with respect to host protein targets, likely contributing to the range of disease. Pharmacological inhibition of the 3C-like3 protease has revealed remarkable reduction in hospitalization and death in phase 2/3 clinical studies. However, the mechanisms responsible for the pathology mediated by those proteases are still unclear. In this study, we develop a bioinformatic algorithm, leveraging experimental data from SARS-CoV, to predict host cleavage targets of the SARS-CoV-2 3C-like protease, or 3CLPro. We capture targets of the 3CL protease described previously for SARS-CoV, and we identify hundreds of new putative targets. We experimentally validate a number of these predicted targets, including the giant sarcomeric protein Obscurin, and show that expression of 3CL protease alone recapitulates the sarcomeric disorganization seen by SARS-CoV-2 infection of hiPSC-derived cardiomyocytes. Our data provide a resource to identify putative host cleavage targets of 3CL protease that contribute to mechanisms and heterogeneity of disease in COVID-19 and future coronavirus outbreaks.

microbiology↗

bioRxiv2021

DNA motif analysis of shear stress responsive endothelial enhancers reveals differential association of KLF and ETV/ETS binding sites with gained and lost enhancers

Endothelial cells (EC) lining blood vessels are exposed to mechanical forces, such as shear stress exerted by the flowing blood. These forces control many aspects of EC biology, including vascular tone, cell migration and proliferation in addition to cell size and shape. Despite a good understanding of the genes and signaling pathways responding to shear stress, our insights into the transcriptional regulation of these responses is much more limited. In particular, we do not know the different sets of regulatory elements (enhancers) that might control increases or decreases in gene expression. Here, we set out to study changes in the chromatin landscape of human umbilical vein endothelial cells (HUVEC) exposed to laminar shear stress. To do so, we performed ChIP-Seq for H3K27 acetylation, indicative of active enhancer elements and ATAC-Seq to mark regions of open chromatin in addition to RNA-Seq on HUVEC exposed to 6 hours of laminar shear stress. Our results show a correlation of gained and lost enhancers with up- and downregulated genes, respectively. DNA motif analysis revealed an over-representation of KLF transcription factor (TF) binding sites in gained enhancers, while lost enhancers contained more ETV/ETS motifs. We validated a subset of flow responsive enhancers using luciferase-based reporter constructs and CRISPR-Cas9 mediated genome editing. Lastly, we characterized shear stress responsive genes in ECs of zebrafish embryos using RNA-Seq. Together, our results reveal the presence of shear stress responsive DNA regulatory elements and lay the groundwork for the future exploration of these elements and the TFs binding to them in controlling EC biology.

genomics↗

bioRxiv2020

Ciliation of muscle stem cells is critical to maintain regenerative capacity and is lost during aging

During aging, the regenerative capacity of muscle stem cells (MuSCs) decreases, diminishing the ability of muscle to repair following injury. We performed a small molecule library screen and discovered that the proliferation and expansion of aged MuSCs is regulated by signal transduction pathways organized by the primary cilium, a cellular protrusion that serves as a sensitive sensory organelle. Abolishing MuSC cilia in vivo severely impaired injury-induced muscle regeneration. In aged muscle, a cell intrinsic defect in MuSC ciliation leading to impaired Hedgehog signaling was associated with the decrease in regenerative capacity. This deficit could be overcome by exogenous activation of Hedgehog signaling which promoted MuSC expansion, both in vitro and in vivo. Delivery of the small molecule Smoothened agonist (SAG) to muscles of aged mice restored regenerative capacity leading to increased strength post-injury. These findings provide fresh insights into the signaling dysfunction in aging and identify the ciliary Hedgehog signaling pathway as a potential therapeutic target to counter the loss of muscle regenerative capacity which accompanies aging.

cell biology↗