The actin depolymerizing factor destrin serves as a negative feedback inhibitor of smooth muscle cell differentiation

Area of Science:

• Molecular Biology
• Cell Biology
• Cardiovascular Research

Background:

• Smooth muscle cell (SMC) phenotype is regulated by RhoA signaling and serum response factor (SRF)-dependent gene expression.
• Genome-wide analyses suggested destrin (DSTN) is regulated in an SMC-selective manner, prompting investigation into its role.

Purpose of the Study:

• To identify transcription mechanisms controlling DSTN expression in SMCs.
• To determine if DSTN regulates SMC function and phenotype.
• To explore DSTN as a therapeutic target for vascular diseases like atherosclerosis and restenosis.

Main Methods:

• Immunohistochemical analyses to assess DSTN expression in mouse tissues and human GTEx data.
• Identification and functional characterization of SMC-selective regulatory regions controlling DSTN.
• siRNA-mediated depletion of DSTN to assess its impact on SMC differentiation, migration, and proliferation.
• Analysis of RhoA, TGF-β, and Notch signaling pathways in regulating DSTN expression.

Main Results:

• DSTN exhibits strong, SMC-selective expression, regulated by MRTF-A, RBPJ, and SMAD transcription factors via a specific enhancer.
• RhoA and TGF-β signaling upregulate DSTN, while Notch inhibition downregulates it; DSTN expression decreases with carotid artery injury and PDGF-BB treatment.
• DSTN depletion enhances SMC differentiation markers, reduces SMC migration and proliferation, and increases MRTF-A nuclear localization.

Conclusions:

• DSTN acts as a negative feedback inhibitor of RhoA/SRF-dependent gene expression in SMCs, promoting phenotypic modulation.
• DSTN plays a critical role in regulating SMC differentiation, migration, and proliferation.
• Targeting DSTN offers potential therapeutic strategies for atherosclerosis and restenosis.