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Transforming growth factor ?1 suppresses proinflammatory gene program independent of its regulation on vascular smooth muscle differentiation and autophagy.

ABSTRACT: Transforming growth factor ? (TGF?) signaling plays crucial roles in maintaining vascular integrity and homeostasis, and is established as a strong activator of vascular smooth muscle cell (VSMC) differentiation. Chronic inflammation is a hallmark of various vascular diseases. Although TGF? signaling has been suggested to be protective against inflammatory aortic aneurysm progression, its exact effects on VSMC inflammatory process and the underlying mechanisms are not fully unraveled. Here we revealed that TGF?1 suppressed the expression of a broad array of proinflammatory genes while potently induced the expression of contractile genes in cultured primary human coronary artery SMCs (HCASMCs). The regulation of TGF?1 on VSMC contractile and proinflammatory gene programs appeared to occur in parallel and both processes were through a SMAD4-dependent canonical pathway. We also showed evidence that the suppression of TGF?1 on VSMC proinflammatory genes was mediated, at least partially through the blockade of signal transducer and activator of transcription 3 (STAT3) and NF-?B pathways. Interestingly, our RNA-seq data also revealed that TGF?1 suppressed gene expression of a battery of autophagy mediators, which was validated by western blot for the conversion of microtubule-associated protein light chain 3 (LC3) and by immunofluo-rescence staining for LC3 puncta. However, impairment of VSMC autophagy by ATG5 deletion failed to rescue TGF?1 influence on both VSMC contractile and proinflammatory gene programs, suggesting that TGF?1-regulated VSMC differentiation and inflammation are not attributed to TGF?1 suppression on autophagy. In summary, our results demonstrated an important role of TGF? signaling in suppressing proinflammatory gene program in cultured primary human VSMCs via the blockade on STAT3 and NF-?B pathway, therefore providing novel insights into the mechanisms underlying the protective role of TGF? signaling in vascular diseases.

SUBMITTER: Gao P

PROVIDER: S-EPMC6389266 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

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Transforming growth factor β1 suppresses proinflammatory gene program independent of its regulation on vascular smooth muscle differentiation and autophagy.

Gao Ping P Wu Wen W Ye Jiemei J Lu Yao Wei YW Adam Alejandro Pablo AP Singer Harold A HA Long Xiaochun X

Cellular signalling 20180711

Transforming growth factor β (TGFβ) signaling plays crucial roles in maintaining vascular integrity and homeostasis, and is established as a strong activator of vascular smooth muscle cell (VSMC) differentiation. Chronic inflammation is a hallmark of various vascular diseases. Although TGFβ signaling has been suggested to be protective against inflammatory aortic aneurysm progression, its exact effects on VSMC inflammatory process and the underlying mechanisms are not fully unraveled. Here we re ...[more]

PMID: 30006123

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Project description:BackgroundThe osteochondrogenic switch of vascular smooth muscle cells (VSMCs) is a pivotal cellular process in atherosclerotic calcification. However, the exact molecular mechanism of the osteochondrogenic transition of VSMCs remains to be elucidated. Here, we explore the regulatory role of TXNIP (thioredoxin-interacting protein) in the phenotypical transitioning of VSMCs toward osteochondrogenic cells responsible for atherosclerotic calcification.MethodsThe atherosclerotic phenotypes of Txnip-/- mice were analyzed in combination with single-cell RNA-sequencing. The atherosclerotic phenotypes of Tagln-Cre; Txnipflox/flox mice (smooth muscle cell-specific Txnip ablation model), and the mice transplanted with the bone marrow of Txnip-/- mice were analyzed. Public single-cell RNA-sequencing dataset (GSE159677) was reanalyzed to define the gene expression of TXNIP in human calcified atherosclerotic plaques. The effect of TXNIP suppression on the osteochondrogenic phenotypic changes in primary aortic VSMCs was analyzed.ResultsAtherosclerotic lesions of Txnip-/- mice presented significantly increased calcification and deposition of collagen content. Subsequent single-cell RNA-sequencing analysis identified the modulated VSMC and osteochondrogenic clusters, which were VSMC-derived populations. The osteochondrogenic cluster was markedly expanded in Txnip-/- mice. The pathway analysis of the VSMC-derived cells revealed enrichment of bone- and cartilage-formation-related pathways and bone morphogenetic protein signaling in Txnip-/- mice. Reanalyzing public single-cell RNA-sequencing dataset revealed that TXNIP was downregulated in the modulated VSMC and osteochondrogenic clusters of human calcified atherosclerotic lesions. Tagln-Cre; Txnipflox/flox mice recapitulated the calcification and collagen-rich atherosclerotic phenotypes of Txnip-/- mice, whereas the hematopoietic deficiency of TXNIP did not affect the lesion phenotype. Suppression of TXNIP in cultured VSMCs accelerates osteodifferentiation and upregulates bone morphogenetic protein signaling. Treatment with the bone morphogenetic protein signaling inhibitor K02288 abrogated the effect of TXNIP suppression on osteodifferentiation.ConclusionsOur results suggest that TXNIP is a novel regulator of atherosclerotic calcification by suppressing bone morphogenetic protein signaling to inhibit the transition of VSMCs toward an osteochondrogenic phenotype.

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Transforming growth factor ?1 suppresses proinflammatory gene program independent of its regulation on vascular smooth muscle differentiation and autophagy.

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Transforming growth factor β1 suppresses proinflammatory gene program independent of its regulation on vascular smooth muscle differentiation and autophagy.

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