Biology subjects

Dey, T.

Publications and source records attributed to Dey, T..

9 recordsLinked to original sources

bioRxiv2026

DLGAP5 promotes vascular cell proliferation and remodeling in pulmonary arterial hypertension

Background: Pulmonary arterial hypertension (PAH) manifests by pulmonary vascular remodeling, caused by hyper-proliferation and apoptosis resistance of resident PA cells, elevated right ventricular (RV) afterload, and death of RV failure. The goal of this study is to determine the role and mechanisms of action of mitotic spindle-associated microtubule regulator DLG associated protein 5 (DLGAP5) in pulmonary vascular remodeling in PAH. Methods: DLGAP5 expression was assessed in human PAH transcriptomic datasets, PAH patients' lung tissues, pulmonary artery smooth muscle cells (PASMCs), and pulmonary artery adventitial fibroblasts (PAAFs). Loss-of-function, molecular, functional, RNAseq, and network analyses were performed. Smooth muscle (SM)-specific DLGAP5 knockdown using adeno-associated virus serotype 6 (AAV6) in mice with SU5416/hypoxia-induced PH was performed. Results: DLGAP5 was overaccumulated in small muscular PAs, PASMCs, and PAAFs from PAH lungs. siRNA DLGAP5 down-regulated cyclin A2, suppressed hyper-proliferation, increased pro-apoptotic BIM, and induced apoptosis in human PAH PASMCs and PAAFs. DEP domain containing 1 (DEPDC1) was identified and validated as a downstream effector of DLGAP5 in PAH PASMCs responsible for hyper-proliferation and apoptosis resistance of human PAH PASMCs. SM-specific DLGAP5 knockdown with AAV6-enTagln-shDLGAP5 reversed DEPDC1 overaccumulation in small muscular PAs, reduced PA medial thickness, RV systolic pressure, mean PA pressure, and RV hypertrophy in mice with SuHx-induced PH. Conclusions: DLGAP5 supports proliferation and survival of human PAH PASMCs and PAAFs through up-regulation of cyclin A2, DEPDC1, and suppression of BIM, and promotes PA remodeling and PH in mice. DLGAP5 could serve as a potential molecular target to attenuate pulmonary vascular remodeling in PAH.

cell biology↗

bioRxiv2025

Endothelial GATA6 deficiency suppresses intracellular TLR3-interferon signaling in HPAECs and promotes interferon response in HPASMCs

GATA6 is a key transcription factor crucial for maintaining endothelial cell (EC) homeostasis. The dysregulation of endothelial immune function is a central feature in diseases such as pulmonary arterial hypertension (PAH). In this study, we explored the consequences of GATA6 deficiency in human pulmonary arterial endothelial cells (HPAECs) and its impact on immune response pathways. We report that siRNA-induced GATA6 deficiency or the GATA inhibitor led to significant downregulation of interferon response genes and a marked reduction in toll-like receptor 3 (TLR3) expression. GATA6 overexpression enhanced the expression of these genes, and TLR3 inhibition abrogated this response in HPAECs. Furthermore, conditioned medium (CM) from GATA6-deficient HPAECs upregulated interferon genes in pulmonary artery smooth muscle cells (HPASMCs), indicating a paracrine effect. Overall, these findings highlight the critical role of GATA6 in modulating TLR3 signaling and immune responses in endothelial cells and suggest its involvement in endothelial-smooth muscle cell interactions in vascular inflammation. New and NoteworthyWe show that endothelial GATA6 is required for proper activation of intracellular TLR3-interferon signaling in HPAECs. GATA6 loss diminishes interferon pathway responses in endothelial cells while promoting an exaggerated interferon signature in adjacent smooth muscle cells via secreted factors. This work reveals a new GATA6-dependent mechanism governing endothelial-smooth muscle crosstalk in pulmonary vascular disease.

molecular biology↗

bioRxiv2025

Lactate dehydrogenase-induced DNA Topoisomerase 1 is a novel regulator of smooth muscle cell proliferation and remodeling in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) manifests by increased proliferation and survival of pulmonary vascular cells in small pulmonary arteries (PAs), PA remodeling and unresolved increase of PA pressure. PA smooth muscle cells (PASMCs) in PAH undergo metabolic shift to glycolysis resulting in over-production of lactate, hyper-proliferation, and apoptosis resistance, but the mechanisms are not completely understood. By using lung tissues and pulmonary vascular cells from PAH and non-diseased human lungs, unbiased proteomics, network analysis, and gain-and-loss of function approaches, we here report that up-regulation of lactate dehydrogenase A (LDHA)-lactate axis promotes PASMC-specific over-lactylation and consequent over-accumulation of DNA topoisomerase 1 (TOP1) in small remodeled PAs from PAH lungs, leading to the up-regulation of Akt-mechanistic target of rapamycin 1 (mTORC1) signaling, hyper-proliferation, and reduced apoptosis. Smooth muscle-specific LDHA knockdown prevented, and Ldha inhibitor oxamate reversed SU5416/hypoxia-induced TOP1 accumulation, pulmonary vascular remodeling, and pulmonary hypertension (PH) in mice. Pharmacological inhibition of TOP1 with indotecan suppressed Akt-mTORC1, decreased proliferation, induced apoptosis in human PAH, but not control PASMCs, and reversed PA remodeling, PH, and RV dysfunction in rats. Collectively, these data provide a novel mechanistic link from LDHA-driven lactate over-production through lactylation and overaccumulation of TOP1, to the up-regulation of Akt-mTORC1, hyper-proliferation and apoptosis resistance of PASMCs, pulmonary vascular remodeling, and PH, and identify TOP1 as a new potentially attractive molecular target for the remodeling-focused therapeutic intervention. Take-home messageLDHA-lactate-induced over-lactylation and overaccumulation of Topoisomerase 1 (TOP1) promotes pulmonary artery smooth muscle cell hyper-proliferation, remodeling, and pulmonary arterial hypertension, which are reversed by TOP1 inhibitor indotecan.

cell biology↗

bioRxiv2025

Non-canonical HIPPO-MST1/2 promotes hyper-proliferation of pulmonary vascular cells through CDC20

HIPPO components mammalian Ste20-like protein kinases 1 and 2 (MST1/2) are well described growth suppressors. However, in pulmonary arterial hypertension (PAH), MST1/2 switch their roles and become pro-proliferative and pro-survival molecules, supporting hyper-proliferation of pulmonary artery (PA) smooth muscle cells (PASMCs) and adventitial fibroblasts (PAAFs), remodeling of small PAs, and pulmonary hypertension. Here, we report that MST1/2 promotes hyper-proliferation and apoptosis resistance of human PAH PASMCs and PAAFs by up-regulating cell division cycle protein 20 (CDC20), establishing novel link between HIPPO-MST1/2 and cell cycle regulation in PAH. Authors Contributionsconception and design of the work (EAG, SSP, TVK); acquisition, analysis, and interpretation of data (TD, IZ, LJ, SOO, AP, TA, DL, DG, JRG, PJW, HD, TK); drafting and editing the manuscript (EAG, SSP, TVK, JRG, PJW).

cell biology↗

bioRxiv2024

Breast cancer spheroids prefer activated macrophages as an accomplice: An in vitro study

Cancer, a heterogeneous disease in nature, often requires help from diverse pro-tumor or tumor-associated- cells, which are recruited and persevered within the stroma. Pro-tumor stromal cells provide the essential support needed for tumor growth, metastasis, and development of drug resistance in due time. Tumor-associated macrophages, one of such cells, are essential to tumor microenvironment and tumor survival. In recent years, TAMs have been identified as potential drug targets and therapeutic agents, which encourages the in-depth characterization of their crosstalk with the tumors. The current study has successfully developed a cost-effective in vitro platform for Chemokine Assisted Recruitment of Macrophages to spheroids mimicking the physiology of TAM recruitment. Firstly, monocytic cell line (U937) were converted into activated naive macrophages (M0) and pro-and anti-inflammatory (M1 and M2) subtypes. Monocytes, M0, M1, and M2 macrophages are characterized extensively. Secondly, the naive and polarized macrophages were subjected to chemokine-dependent recruitment into monotypic and heterotypic breast cancer spheroids. The nature of the recruitment is further investigated by assessing the profile of chemokines and chemokine receptors. Recruited macrophages are also observed to manipulate spheroid behavior in many ways. The recruited macrophages also exhibit an increased level of Siglec-1 (CD169), one of the potential TAM markers. The current platforms potential for application can be extended to understand the recruitment process of other immune/stromal cells to solid tumors. It could be a potential addition to the arrays of in vitro platforms developed to screen the efficiency of cell-based immunotherapeutics in the future.

cancer biology↗

bioRxiv2021

Post-transcriptional regulation of glutamate metabolism of Pichia pastoris and development of a glutamate-inducible yeast expression system

Pichia pastoris harbours a unique glutamate utilization pathway in which glutamate dehydrogenase 2 (GDH2), aspartate aminotransferase 2 (AAT2) and phosphoenolpyruvate carboxykinase (PEPCK) catalyze the conversion of glutamate to -ketoglutarate, oxaloacetate, and phosphoenolpyruvate respectively in the cytosol. GDH2 and PEPCK are glutamate-inducible enzymes and their synthesis is regulated post-transcriptionally by Rtg1p, a cytosolic basic helix-loop-helix protein via Rtg1p response elements located downstream of TATA box of GDH2 and PEPCK promoters. Glutamate-inducible synthesis of PEPCK is abrogated in{Delta} gdh2 and{Delta} aat2. -ketoglutarate induces PEPCK synthesis in{Delta} gdh2 but not{Delta} aat2. We propose that oxaloacetate derived from glutamate is the inducer of PEPCK synthesis. Enzymes of glutamate utilization pathway are synthesized during carbon starvation and they enable P. pastoris to overcome nutritional stress. Finally, green fluorescent protein can be synthesized efficiently from GDH2 and PEPCK promoters using food-grade monosodium glutamate as inducer indicating that the post-transcriptional regulatory circuit described here can be exploited for the development of glutamate-inducible P. pastoris expression system.

biochemistry↗

bioRxiv2020

Nutritional stress alone can control in vitro tumor formation and its invasive nature

The metastatic nature is an inherent property of the tumor. However, the effect of the environmental stress conditions on tumor microcosm in the context of metastasis needs to be analyzed. This work is proposed to analyze the tumor behavior under multiple metabolic stress conditions, such as deprivation of glucose, protein, and oxygen. The spheroid proliferation rate is observed to be influenced profoundly by the stress level where minimal stress produces compact spheroid and severe stress makes unstable aggregate like structures. It is observed that the non-invasive cancer cells cannot form spheroids under extreme stress. Stress conditions influence the mRNA levels of hypoxic, angiogenic and ECM deformation specific gene clusters. Spheroid reversal assay reveals the quiescent nature of the stressed spheroids under continuous stress conditions. However, after the rescue, the stressed spheroids were found to opt for different migration modalities. Extremely stressed non-invasive spheroids display atypical sprout-like growth within the invasion matrix and severely stressed spheroids can control the migration pattern of mesenchymal stem cells. Thus, it is concluded that multiple nutritional stress influences the spheroid formation and physiology along with the conversion of a non-invasive spheroid into quasi-invasive one.

cancer biology↗

bioRxiv2019

Reversible loss of Hippocampal Function in a Mouse Model of Demyelination/Remyelination

Demyelination of axons in the central nervous system (CNS) is a hallmark of multiple sclerosis (MS) and other demyelinating diseases. Cycles of demyelination, followed by remyelination, appear in the majority of MS patients, and are associated with the onset and quiescence of disease-related symptoms, respectively. Previous studies have shown in human patients and animal models that vast demyelination is accompanied by wide-scale changes to brain activity, but details of this process are poorly understood. We use electrophysiological recordings and nonlinear imaging of fluorescence from genetically-encoded calcium indicators to monitor the activity of hippocampal neurons during demyelination and remyelination processes over a period of 100 days. We find in vitro that synaptic transmission in CA1 neurons is diminished, and in vivo both CA1 and dentate gyrus (DG) neuronal firing rates are substantially reduced during demyelination and partially recover after a short remyelination period. This new approach allows monitoring how synaptic transmission changes, induced by cuprizone diet, are affecting neuronal activity, and can potentially be used to study the effects of therapeutic interventions in protecting the functionality of CNS neurons.

neuroscience↗

bioRxiv2019

Women in Science and Technology: An Indian scenario

The concept of treating women as equal to their male counterpart became a topic of political debate in Europe during the age of enlightenment (18th Century). The battle towards equal voting rights took approximately 100 years to win, and went until the 19th Century. It was only around 1902-1920 that women got equal voting rights in prominent Western countries followed by others. Amidst the celebration of womens vote centenary throughout the world, the issue of equal rights to education and work is still waiting for the proper attention. Historically the presence of women in educational, technological and scientific fields remains mostly marginal. In this article, the current state of under-representation of women in the science and technology community is depicted, primarily highlighting the Indian scenario. It is observed that throughout India, and amongst the relatively developed countries of the world, the presence of women in highly prestigious Institutes and Universities remains negligible even in this day and age. The probable causes behind such inequality need to be analyzed, addressed and looked upon for remedial purposes.

scientific communication and education↗