Single nucleus sequencing and functional in vivo studies reveal TCF21 as a protective regulator in cardiac fibrosis

by Tousif Azmain
Doctoral thesis
Date of Examination:2024-12-18
Date of issue:2025-07-17
Advisor:Prof. Dr. Elisabeth Zeisberg
Referee:Prof. Dr. André Fischer
Referee:Prof. Dr. Argyris Papantonis
Persistent Address: http://dx.doi.org/10.53846/goediss-11311

 

 

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Abstract

English

Cardiac fibrosis remains an unsolved clinical challenge, significantly contributing to mortality in chronic heart disease patients, with no specific antifibrotic therapy currently available. In our study, we performed single nucleus RNA sequencing (snRNA-seq) to track pathological changes in fibrotic heart tissue from aortic stenosis (AS) patients and to identify cell-specific candidate genes involved in cardiac fibrosis. We conducted single nucleus RNA sequencing (snRNA-seq) on human fibrotic AS and non-failing donor heart samples. The final dataset consisted of 41,330 nuclei distributed across 28 cell clusters representing six major cell types. SnRNA-seq revealed a disease-specific subpopulation of fibroblasts, characterized by the presence of both anti-fibrotic and pro-fibrotic markers. Interestingly, TCF21, a basic helix-loop-helix transcription factor, was identified as a potential master regulator within this distinct fibroblast population, and we performed functional studies to identify its role in disease progression accordingly. Loss of TCF21 in cardiac fibroblasts caused increased myofibroblast-like gene expression and differentiation, whereas upregulation of TCF21 in cardiac fibroblasts exerted an anti-fibrotic effect. Adeno-associated virus (AAV)–mediated cardiac fibroblast-specific knockdown and overexpression in vivo further demonstrate that TCF21 improves cardiac remodeling. This investigation highlights the role of TCF21 as a protective regulator in cardiac fibrosis. Moreover, the upregulation of TCF21 holds promise as a strategy for treating cardiac fibrosis. Our findings enhance the understanding of fibrogenesis in AS patients, potentially guiding the development of targeted treatments.
Keywords: Cardiac disease; Fibrosis; TCF21; CRISPR; Aortic stenosis; Single cell sequencing; Single nuclei RNA sequencing; Cardiac gene therapy
Schlagwörter: Cardiac disease; Fibrosis; TCF21; CRISPR; Aortic stenosis; Single nuclei RNA sequencing; Single cell sequencing; Cardiac gene therapy