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Nuclear Smooth Muscle a-actin in Vascular Smooth Muscle Cell Differentiation. Research square Kwartler, C. S., Pedroza, A. J., Kaw, A., Guan, P., Ma, S., Duan, X. Y., Kernell, C., Wang, C., Pinelo, J. E., Borthwick, M. S., Chen, J., Zhong, Y., Sinha, S., Shen, X., Fischbein, M. P., Milewicz, D. M. 2023

Abstract

Missense variants throughout ACTA2, encoding smooth muscle a-actin (aSMA), predispose to adult onset thoracic aortic disease, but variants disrupting arginine 179 (R179) lead to Smooth Muscle Dysfunction Syndrome (SMDS) characterized by childhood-onset diverse vascular diseases. Our data indicate that aSMA localizes to the nucleus in wildtype (WT) smooth muscle cells (SMCs), enriches in the nucleus with SMC differentiation, and associates with chromatin remodeling complexes and SMC contractile gene promotors, and the ACTA2 p.R179 variant decreases nuclear localization of aSMA. SMCs explanted from a SMC-specific conditional knockin mouse model, Acta2SMC-R179/+, are less differentiated than WT SMCs, both in vitro and in vivo, and have global changes in chromatin accessibility. Induced pluripotent stem cells from patients with ACTA2 p.R179 variants fail to fully differentiate from neural crest cells to SMCs, and single cell transcriptomic analyses of an ACTA2 p.R179H patient's aortic tissue shows increased SMC plasticity. Thus, nuclear aSMA participates in SMC differentiation and loss of this nuclear activity occurs with ACTA2 p.R179 pathogenic variants.

View details for DOI 10.21203/rs.3.rs-1623114/v1

View details for PubMedID 36909460

View details for PubMedCentralID PMC10002808