Biology subjects

Sethu, P.

Publications and source records attributed to Sethu, P..

4 recordsLinked to original sources

bioRxiv2026

Endothelial CD36 links arteriolar remodeling to metabolic and immune alterations in Alzheimer's disease

Alzheimer's disease (AD) is accompanied by profound cerebrovascular dysfunction, yet it remains unclear whether endothelial abnormalities reflect only vascular injury or altered regulatory states connecting vascular remodeling with metabolic and immune function. We integrated human brain transcriptomic and histopathological data with complementary mouse genetic and human iPSC-derived endothelial models to examine a CD36-centered endothelial-state framework in AD. Analysis of the Seattle Alzheimer's Disease Brain Cell Atlas identified three CD36-expressing endothelial populations; intermediate-CD36 Endo 2 predominated in both reference and AD samples, although the relative subset distributions differed. In hippocampal and cortical tissue from six AD patients, endothelial CD36 expression was observed in structurally abnormal arterioles with disrupted mural organization. In complementary mouse studies, endothelial PKD1 deficiency was accompanied by increased vascular CD36 and cerebrovascular abnormalities, whereas endothelial CD36 deletion altered lipid-metabolic and innate-immune-associated transcriptional programs, including AD-relevant genes and pathways, under metabolic-inflammatory stress. To assess whether distinct human endothelial backgrounds remained pharmacologically responsive, we treated control and CRISPR-engineered PSEN1 E276A iPSC-derived ECs with GS4898, a small molecule previously linked to arterial specification. Both maintained endothelial identity but displayed different baseline transcriptional profiles and shared as well as cell-line-dependent responses to GS4898. Together, our study identifies a CD36-associated vascular phenotype in human AD, demonstrates CD36-dependent regulation of brain endothelial metabolic-immune transcriptional programs in vivo, and reveals endothelial transcriptional responsiveness to pharmacologic perturbation. The observed endothelial transcriptional plasticity may provide a basis for developing state-selective therapeutic strategies targeting cerebrovascular dysfunction in AD.

neuroscience↗

bioRxiv2025

Development of conditional-siRNA programmable riboswitch for targeting adverse cardiac remodeling

Heart Failure (HF) remains a global epidemic and a significant healthcare burden, with an unmet need for novel therapies to target the preceding pathological hypertrophy in vulnerable patients. Here we report the development of novel conditional-siRNA (Cond- siRNA) constructs that are selectively activated by disease-specific RNA biomarkers to enable cell-specific inhibition of a target disease-causing RNA. We designed a Cond- siRNA that can be activated by nppa mRNA, upregulated specifically in CMs under pathological stress, to silence the key pro-hypertrophic gene calcineurin by the effector siRNA. In cellular models including neonatal rat ventricular myocyte (NRVM) and rat cardiomyocyte cell-line (H9C2), Cond-siRNA exhibited low baseline activity in the absence of the disease biomarker but achieved targeted calcineurin silencing upon nppa mRNA induction by phenylephrine (PE)-induced stress in a two-dimensional (2D) cell culture system and pressure overload in three-dimensional (3D) heart-on a chip system. NRVM transfection with the Cond-siRNA resulted in a decreased expression of calcineurin mRNA specifically after PE or pressure-overload treatment, but not after vehicle treatment, proving nppa mRNA-specific activation of the effector siRNA against calcineurin. Specificity was confirmed as Cond-siRNA did not significantly silence calcineurin in cardiac fibroblasts and T cells, lacking nppa expression. Reduced calcineurin protein levels and NFATc1 nuclear translocation correlated with decreased NRVM hypertrophy after PE treatment, confirming Cond-siRNAs efficacy. This study offers proof-of-concept for Cond-siRNA as a targeted therapy to mitigate hypertrophic progression, paving the way for novel HF treatments. One sentence summaryConditional-siRNA targeting adverse cardiac remodeling GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/633434v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1b6532borg.highwire.dtl.DTLVardef@10e3836org.highwire.dtl.DTLVardef@8c839eorg.highwire.dtl.DTLVardef@1152883_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2020

Repurposing Nintedanib for Pathological Cardiac Remodeling and Dysfunction

BackgroundHeart Failure (HF) is the leading cause of death worldwide. Myocardial fibrosis, one of the clinical manifestations implicated in almost every form of heart disease, contributes significantly to HF development. However, there is no approved drug specifically designed to target cardiac fibrosis. Nintedanib (NTB) is an FDA approved tyrosine kinase inhibitor for idiopathic pulmonary fibrosis (IPF) and chronic fibrosing interstitial lung diseases (ILD). The favorable clinical outcome of NTB in IPF patients is well established. Furthermore, NTB is well tolerated in IPF patients irrespective of cardiovascular comorbidities. However, there is a lack of direct evidence to support the therapeutic efficacy and safety of NTB in cardiac diseases. Methods and ResultsWe examined the effects of NTB treatment on cardiac fibrosis and dysfunction using a murine model of HF. Specifically, 10 weeks old C57BL/6J male mice were subjected to Transverse Aortic Constriction (TAC) surgery. NTB was administered once daily by oral gavage (50mg/kg) till 16 weeks post-TAC. Cardiac function was monitored by serial echocardiography. Histological analysis and morphometric studies were performed at 16 weeks post-TAC. In the control group, systolic dysfunction started developing from 4 weeks post-surgery and progressed till 16 weeks. However, NTB treatment prevented TAC-induced cardiac functional decline. In another experiment, NTB treatment was stopped at 8 weeks, and animals were followed till 16 weeks post-TAC. Surprisingly, NTBs beneficial effect on cardiac function was maintained even after treatment interruption. NTB treatment remarkably reduced cardiac fibrosis as confirmed by Massons trichome staining and decreased expression of collagen genes (COL1A1, COL3A1). Compared to TAC group, NTB treated mice showed lower HW/TL ratio and cardiomyocyte cross-sectional area. Our in vitro studies demonstrated that NTB prevents myofibroblast transformation, TGF{beta}1-induced SMAD3 phosphorylation, and production of fibrogenic proteins (Fibronectin-1). However, NTB significantly altered vital signaling pathways in both, isolated fibroblast and cardiomyocytes, suggesting that its biological effect and underlying cardiac protection mechanisms are not limited to fibroblast and fibrosis alone. ConclusionOur findings provide a proof of concept for repurposing NTB to combat adverse myocardial fibrosis and encourage the need for further validation in large animal models and subsequent clinical development for HF patients.

pathology↗

bioRxiv2017

Elucidation of dose-dependent transcriptional events immediately following ionizing radiation exposure

Long duration space missions expose astronauts to ionizing radiation events associated with highly energetic and charged heavy particles. Such exposure can result in chromosomal aberrations increasing the likelihood of the development of cancer. Early detection and mitigation of these events is critical in providing positive outcomes. In order to aid in the development of portable devices used to measure radiation exposure, we constructed a genome-wide screen to detect transcriptional changes in peripheral blood lymphocytes shortly after (approximately 1 hour) radiation exposure at low (0.3 Gy), medium (1.5 Gy) and high (3.0 Gy) doses compared to control (0.0 Gy) using Affymetrix(R) Human Gene 1.0 ST v1 microarrays. Our results indicate a number of sensitive and specific transcriptional profiles induced by radiation exposure that can potentially be implemented as biomarkers for radiation exposure as well as dose effect. For overall immediate radiation exposure, KDELC1, MRPS30, RARS, and HEXIM1 were determined to be effective biomarkers while PRDM9, CHST4, and SLC26A10 were determined to be biomarkers specific to 0.3 Gy exposure; RPH, CCDC96, WDYHV1, and IFNA16 were identified for 1.5 Gy exposure; and CWC15, CHCHD7, and DNAAF2 were determined to be sensitive and specific to 3.0 Gy exposure. The resulting raw and analyzed data are publicly available through NCBI's Gene Expression Ominibus via accession GSE64375.

bioinformatics↗