Biology subjects

Keswani, S. G.

Publications and source records attributed to Keswani, S. G..

5 recordsLinked to original sources

bioRxiv2023

Genomic and Proteomic Analysis of Patients with Reoccurring Discrete Subaortic Stenosis

Discrete subaortic stenosis (DSS) is a pediatric condition in which a fibrotic membrane forms within the left ventricular outflow track. The fibrotic membrane is removed surgically; however, there is a high rate of reoccurrence which requires a second surgery. There are currently no tools available to predict the risk of reoccurrence in DSS patients, a limitation addressed by this study. In this study, we analyzed resected fibrotic membranes for DSS patients at the time of first surgery for non-recurrent and recurrent patients, and at the time of second surgery for recurrent patients. RNA-sequencing was conducted to obtain a global screen of changes in RNA expression while mass spectrometry was used to obtain a global screen of changes in protein expression. The results from the RNA-sequencing and mass spectrometry provide valuable insight into genes and the proteins that are differentially regulated in recurrent vs non-recurrent DSS patients.

molecular biology↗

bioRxiv2022

Application of Physiological and Pathological Wall Shear Stress to Endocardial Endothelial Cells Triggers Complex Signaling Pathways

Discrete subaortic stenosis (DSS) is a congenital heart disease in which a fibrotic membrane forms below the aortic valve; the underlying cellular mechanisms are currently unknown. Since an elevated pressure gradient in the left ventricular outflow tract (LVOT) is a distinguishing feature of DSS, it is hypothesized that the membrane formation is caused by elevated wall shear stress applied to the endocardial endothelial cells (EECs) that line the LVOT, triggering fibrosis. To correlate shear stress to an EEC fibrotic phenotype, we applied fluid shear stress to EECs at physiological and pathological shear rates using a cone-and-plate device, designed to recapitulate physiological wall shear stress in a controlled in vitro environment. Controlled shear stress regimes were applied to EECs to replicate the conditions observed in DSS patients. We found that elevated shear stress triggered EEC alignment as well as endothelial-to-mesenchymal transformation (EndMT) signaling pathways driven by upregulation of SNAI1 gene expression. The EECs were then treated with a small molecule inhibitor of Snail1 protein, CYD19, to attempt to attenuate EndMT signaling, and subsequently subjected to pathological shear stress. The Snail1 inhibitor did downregulate selected markers of EndMT signaling, although only transiently. Interestingly, the application of shear stress had a greater effect on the EEC gene and protein expression than did the Snail1 inhibition. This investigation of EEC response to shear stress reveals the pronounced and complex effect of this mechanical stimulation on the EEC phenotype. Further study should reveal the mechanisms that drive fibrosis and the formation of the DSS membrane.

bioengineering↗

bioRxiv2022

Isolation and Characterization of Endocardial Endothelial Cells from the Left Ventricular Wall and Outflow Tract of the Porcine Heart

The heart contains six different types of endothelial cells, each with a unique function. We sought to characterize the endocardial endothelial cells (EECs), which line the chambers of the heart. EECs are relatively understudied, yet their dysregulation can lead to various cardiac pathologies. Due to the lack of commercial availability of this cell line, we developed a protocol for isolating EECs from porcine hearts and detailed our methodology for establishing populations of EECs through cell sorting. Additionally, we compared the EEC phenotype and fundamental behaviors to a well-studied endothelial cell line, human umbilical vein endothelial cells (HUVECs). The EECs were slightly smaller than HUVECs, and they stained positively for classic endothelial phenotypic markers such as CD31, von Willebrand Factor, and vascular endothelial (VE) cadherin. The EECs proliferated more quickly than HUVECs, yet migrated more slowly to cover a scratch wound assay. Finally, the EECs maintained their robust endothelial phenotype (expression of CD31) through more than a dozen passages. In contrast, the HUVECs showed significantly reduced CD31 expression in later passages. These important phenotypic differences between EECs and HUVECs highlight the need for researchers to utilize the most relevant cell lines when studying or modeling a disease of interest. Impact statementMany researchers model cardiovascular disease via tissue engineering to determine disease etiology on the cellular and molecular level. However, researchers usually rely on commercially-available cell lines, which can result in utilizing cells that are not specific to the region of the heart being modeled and could lead to incorrect conclusions. By providing a detailed protocol for isolating and purifying endocardial endothelial cells, we are enabling other researchers to access this cell line and model cardiovascular disease states more accurately.

pathology↗

bioRxiv2022

Endogenous IL-10 Contributes to Wound Healing and Regulates Tissue Repair

BackgroundInterleukin-10 (IL-10) is essential in fetal regenerative wound healing and likewise promotes a regenerative phenotype in adult dermal wounds. However, the role of endogenous IL-10 in postnatal dermal wound healing is not well established. We sought to determine the role of IL-10 in murine full thickness, excisional wounds that are splinted to prevent contracture and mimic human patterns of wound closure. MethodsFull thickness, excisional wounds were made in wildtype (WT) and IL-10-/- mice on a C57BL/6J background (F/M, 8wks old). In a subset of wounds, contraction was prevented by splinting with silicone stents (stenting) and maintaining a moist wound microenvironment using a semi-occlusive dressing. Wounds were examined for re-epithelialization, granulation tissue deposition, and inflammatory cell infiltrate at day 7 and fibrosis and scarring at day 30 post-wounding. ResultsWe observed no difference in wound healing rate between WT and IL-10-/- mice in either the stented or unstented group. At day 7, unstented IL-10-/- wounds had a larger granulation tissue area and more inflammatory infiltrate than their WT counterparts. However, we did observe more F4/80+ cell infiltrate in stented IL-10-/- wounds at day 7. At day 30, stented wounds had increased scar area and epithelial thickness compared to unstented wounds. ConclusionsThese data suggest that endogenous IL-10 expression does not alter closure of full thickness excisional wounds when wound hydration and excessive contraction are controlled. However, the loss of IL-10 leads to increased inflammatory cell infiltration and scarring. These data suggest that previous reports of increased rates of healing in IL-10-/- mice ought to be revisited considering recent advances in wound healing models. Moreover, these new findings suggest that IL-10 contributes to regulation of inflammation without compromising the healing response.

molecular biology↗

bioRxiv2021

Global anti-tumor immunity after localized, bioengineered Treg depletion

Over 90% of deaths from cancer occur due to solid tumors, occurring at a rate of [~]1,500 deaths per day in the US, highlighting a profound and unmet need for new therapies. Solid tumors evade clearance by T cells due to a variety of immunosuppressive properties of the tumor microenvironment. However, this immunosuppression cannot be easily blocked on a global level because systemic activation of the immune system elicits a host of complications. An ideal therapy for solid tumors would act locally to activate the immune response without evoking global adverse effects. Here we present a biodegradable, macroporous scaffold that is implanted adjacent to the tumor and suppresses the main obstacle to cancer immunosurveillance: intratumoral regulatory T cells. The scaffold also promotes the recruitment and activation of T cell effectors into the tumor, resulting in clearance of otherwise aggressive and fatal tumors in mice. Unexpectedly, the local depletion of Tregs results in an "immunological abscopal effect" acting on distant tumors. We demonstrate that this versatile platform can also deliver tumor-antigen-specific T cells directly to the peri-tumoral environment, bypassing difficulties in intravenous delivery including the environmental barriers imposed by the tumors vasculature. By orchestrating multiple local immunomodulatory treatments, this scaffold offers a general approach to engineer T-cell responses to solid tumors without systemic toxicities.

immunology↗