Platelet-Derived Microvesicles Promote VSMC Dedifferentiation After Intimal Injury via Src/Lamtor1/mTORC1 Signaling

Area of Science:

• Vascular Biology
• Cell Signaling
• Platelet Biology

Background:

• Vascular smooth muscle cell (VSMC) phenotypic switching drives vascular remodeling, leading to hyperplasia and restenosis post-injury.
• Activated platelets at injury sites release platelet-derived microvesicles (PMVs), implicated in cellular processes.

Purpose of the Study:

• To investigate the role of PMVs in VSMC phenotypic switch and elucidate the underlying molecular mechanisms.
• To identify potential therapeutic targets for intimal hyperplasia.

Main Methods:

• In vivo studies of intimal injury models.
• In vitro experiments using PMVs from collagen-activated platelets.
• Small interfering RNA (siRNA) for Lamtor1 knockdown.
• Src inhibitor treatment.
• Analysis of mTORC1 signaling pathway activation (S6K, 4E-BP1 phosphorylation).
• SMC-specific Lamtor1 knockout mouse model.

Main Results:

• PMVs promoted VSMC dedifferentiation, induced Lamtor1 expression, and activated mTORC1 signaling.
• Lamtor1 knockdown attenuated PMV-induced effects.
• Src inhibition reversed PMV-mediated VSMC dedifferentiation, Lamtor1 induction, and mTORC1 activation.
• Lamtor1 deficiency in SMCs reduced intimal hyperplasia post-injury.

Conclusions:

• PMVs secreted by activated platelets promote VSMC dedifferentiation through the Src/Lamtor1/mTORC1 signaling pathway.
• Lamtor1 represents a potential therapeutic target for mitigating intimal hyperplasia and restenosis.