Stiff (50 kPa) extracellular matrix increased NLRP3 expression in vascular smooth muscle cells via FAK/mTOR/nuclear-actin/SREBP signalling compared to a soft (2 kPa) matrix.
This study identifies a novel pathway explaining how arterial stiffening promotes a pro-inflammatory VSMC phenotype by priming the NLRP3-inflammasome.
Arterial stiffening is associated with an increased risk of cardiovascular disease (CVD) morbidity and mortality. We investigated the effects of ECM-stiffness on the expression of NLRP3, a component of the NLRP3-inflammasome. VSMC interacting with a stiff (50 kPa) ECM displayed elevated expression of NLRP3 protein and mRNA, compared to cells interacting with a soft (2 kPa) ECM. ECM-stiffness enhanced levels of pre-spliced NLRP3 RNA and NLRP3 promoter reporter gene activity, indicating transcriptional upregulation of the NLRP3 gene. Increased ECM stiffness increased phosphorylation of FAK and the S6 protein. ECM stiffness reduced levels of nuclear actin monomer in a FAK and mTOR-dependent manner. NLRP3 expression was dependent on FAK and mTOR and antagonised by elevated nuclear actin monomer. Analysis of the NLRP3 promoter, identified an SREBP element. SREBP activity was increased in response to ECM-stiffness in a FAK, mTOR and nuclear actin monomer-dependent manner. Pharmacological or siRNA-mediated inhibition of SREBP significantly reduced NLRP3 expression. Taken together, this novel pathway helps to explain how arterial stiffening promotes a pro-inflammatory VSMC phenotype by priming the NLRP3-inflammasome.
Hadfield et al. (Mon,) reported a other. Stiff (50 kPa) extracellular matrix vs. Soft (2 kPa) extracellular matrix was evaluated on NLRP3 protein and mRNA expression. Stiff (50 kPa) extracellular matrix increased NLRP3 expression in vascular smooth muscle cells via FAK/mTOR/nuclear-actin/SREBP signalling compared to a soft (2 kPa) matrix.
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