Biology subjects

Zhyvylo, I.

Publications and source records attributed to Zhyvylo, I..

4 recordsLinked to original sources

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↗

bioRxiv2023

PAI-1 Deficiency Drives Pulmonary Vascular Smooth Muscle Remodeling and Pulmonary Hy-pertension

Pulmonary arterial hypertension (PAH) is a progressive and potentially a rapidly fatal disease characterized by vasoconstriction and remodeling of small pulmonary arteries (PA) leading to increased pulmonary vascular resistance and right heart failure. Central to the remodeling process is a switch of the smooth muscle cells in small PAs (PASMC) to a proliferative, apoptosis-resistant phenotype. There is reason to suspect that the plasminogen activator system may play an important role in the remodeling program in PAH based on its roles in vascular post-injury restenosis, fibrosis, angiogenesis and tumorigenesis. Plasminogen activator inhibitor-1 (PAI-1) is the primary physiological inhibitor of the plasminogen activators - urokinase-type and tissue-type (uPA and tPA, respectively). Immunohisto- chemical and immunoblot analyses revealed that PAI-1 was deficient in smooth muscle areas of small remodeled PAs and early-passage PASMC from subjects with PAH compared to non-PAH controls. PAI1-/- male and female mice developed spontaneous pulmonary vascular remodeling and pulmonary hypertension (PH) as evidenced by significant increase in PA medial thickness, systolic right ventricular pressure, and right ventricular hypertrophy. Lastly, the uPA inhibitors upamostat (WX-671) and amiloride analog BB2-30F down-regulated mTORC1 and SMAD3, restored PAI-1 levels, reduced proliferation, and induced apoptosis in human PAH PASMC. We examined the effect of inhibition of uPA catalytic activity by BB2-30F on the development of SU5416/Hypoxia (SuHx)-induced PH in mice. Vehicletreated SuHx-exposed mice had up-regulated mTORC1 in small PAs, developed pulmonary vascular remodeling and PH, as evidenced by significant increase of PA MT, sRVP, RV hypertrophy, and a significant decrease in the pulmonary artery acceleration time/pulmonary ejection time (PAAT/PET) ratio compared to age- and sex-matched normoxia controls, whereas BB2-30F-treated group was protected from all these pathological changes. Taken together, our data strongly suggest that PAI-1 down- regulation in PASMC from human PAH lungs promotes PASMC hyper-proliferation, remodeling, and spontaneous PH due to unopposed uPA activation. Further studies are needed to determine the potential benefits of targeting the PAI-1/uPA imbalance to attenuate the progression and/or reverse pulmonary vascular remodeling and PH.

cell biology↗