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Biology subjects

Prehar, S.

Publications and source records attributed to Prehar, S..

3 recordsLinked to original sources

Microtubule-associated protein 1S (MAP1S): a cardioprotective factor against post-myocardial infarction remodeling via apoptosis inhibition

Adverse cardiac remodeling following myocardial infarction (MI) are driven by processes including autophagy and apoptosis. While microtubule-associated protein 1S (MAP1S) is known to regulate autophagy, its role in the cardiac pathological conditions remains unclear. This study aimed to elucidate the role of MAP1S and its underlying mechanisms in pathological cardiac remodeling. Following MI, MAP1S knockout mice exhibited increased mortality, impaired cardiac function, and elevated apoptosis. Similarly, MAP1S silencing in cultured cardiomyocytes augmented apoptosis under oxidative stress. Mechanistic investigation revealed potential link to the Hippo pathway. MAP1S knockdown in cardiomyocytes increased Mammalian Ste-20 like 1/2 (MST1/2) activation and reduced Yes-associated protein (YAP) activity, potentially explaining apoptosis regulation. Conversely, MAP1S overexpression reduced apoptosis and positively modulated autophagy. Importantly, in vivo modRNA-mediated MAP1S overexpression protected against apoptosis and adverse remodeling. This study reveals that MAP1S protects the heart from excessive apoptosis and adverse remodeling following MI, likely by modulating the Hippo signaling pathway.

cell biology↗

Regional Vulnerability of Cardiac Chambers to Radiotherapy: A Multi-Omics Perspective

The heart is highly vulnerable to radiotherapy (RT)-induced injury, leading to molecular and structural remodeling collectively termed radiation-induced cardiac toxicity (RICT). Although several biological pathways have been implicated, the regional, cardiac-specific molecular responses to radiation exposure remain incompletely understood. Here, a multi-omics approach was adopted to longitudinally characterise the unique responses to radiation of the heart base (including ventricular base and right atrium), or the heart apex. Ventricular base irradiation induced a cardiomyopathy phenotype, with pronounced molecular perturbations in metabolism and electrical conduction, while changes related to tissue structure were predominant following apex-directed RT. In the right atrium, irradiation drives fibrotic tissue remodelling, leading to an increased propensity for atrial fibrillation, underpinned by changes in sarcomere organisation. This study represents a comprehensive characterisation of differential spatiotemporal radiation effects in the heart and highlights biological and functional pathways that are potentially clinically actionable for cardiac radioprotection and monitoring.

cell biology↗

TNAP limits TGF-β-dependent cardiac and skeletal muscle fibrosis by inactivating SMAD2/3 transcription factors

Fibrosis is associated with almost all forms of chronic cardiac and skeletal muscle diseases. The accumulation of extracellular matrix impairs the contractility of muscle cells contributing to organ failure. Transforming growth factor beta (TGF-{beta}) plays a pivotal role in fibrosis, activating pro-fibrotic gene programs via phosphorylation of SMAD2/3 transcription factors. However, the mechanisms that control de-phosphorylation of SMAD2/3 have remained poorly characterized. Here we show that tissue non-specific alkaline phosphatase (TNAP) is highly upregulated in hypertrophic hearts and in dystrophic skeletal muscles, and the abrogation of TGF-{beta} signalling in TNAP positive cells reduces vascular and interstitial fibrosis. We show that TNAP co-localizes and interacts with SMAD2. TNAP inhibitor MLS-0038949 increases SMAD2/3 phosphorylation, while TNAP overexpression reduces SMAD2/3 phosphorylation and the expression of downstream fibrotic genes. Overall our data demonstrate that TNAP negatively regulates TGF-{beta} signalling and likely represents a mechanism to limit fibrosis.\n\nSummary statementThis paper shows that tissue non-specific alkaline phosphatase negatively regulates TGF-{beta} signalling and may represent a mechanism to limit fibrosis through SMAD dephosphorylation.

cell biology↗