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Vascular smooth muscle cells (VSMCs) is a vital accelerator in the late phase of diabetic atherosclerosis, but the underlying mechanism remains unclear. The aim of our study was to investigate whether activin receptor-like kinase 7 (ALK7)-Smad2/3 pathway plays an important role in VSMC apoptosis of diabetic atherosclerosis. It was shown that ALK7 expression was obviously elevated in the aorta of ApoE-/-mice with type 2 diabetes mellitus. Inhibition of ALK7 expression significantly improved the stability of atherosclerotic plaques and reduced cell apoptosis. Further experiments showed that ALK7 knockdown stabilized atherosclerotic plaques by reducing VSMC apoptosis via activating Smad2/3. Our study uncovered the important role of ALK7-Smad2/3 signaling in VSMCs apoptosis, which might be a potential therapeutic target in diabetic atherosclerosis. [ABSTRACT FROM AUTHOR]

Laminectomy is commonly performed to treat degenerative spinal diseases by reducing compression on the spinal cord and nerve roots. The postoperative epidural fibrosis and epidural adhesions may result in failed back surgery syndrome, which is characterized by the symptoms of lower back pain or leg pain. There is currently no satisfactory treatment for this complication. The pathological processes of epidural fibrosis and epidural adhesions are relevant to the proliferation of fibroblasts, transdifferentiation of fibroblasts into myofibroblasts, and the excessive deposition of extracellular matrix (ECM) protein. According to reports, transforming growth factor-β1 (TGF-β1) played a vital role in the development of fibrosis by promoting aforementioned processes. Decorin, an endogenous proteoglycan and natural inhibitor of TGF-β1, has exhibited prominent anti-fibrosis activity in various scar formation and fibrosis models of many organs. However, the preventive effect of decorin on epidural fibrosis and epidural adhesions requires further investigation. Here, we investigated the therapeutic effects and potential mechanisms of decorin on epidural fibrosis and epidural adhesions. Our results indicated that decorin could significantly suppress the TGF-β1-induced proliferation, transdifferentiation, and extracellular matrix production in primary fibroblasts. Furthermore, Smad2/3 signaling pathway had been demonstrated to be involved in the preventive effect of decorin. Moreover, administration of decorin in vivo could notably inhibit epidural fibrosis and epidural adhesions after laminectomy. To date, there is no approved therapy to target TGF-β1 for the treatment of epidural fibrosis and epidural adhesions after laminectomy. Our research proved the anti-fibrosis effect of decorin, which may provide an effective and promising treatment for epidural fibrosis and epidural adhesions. [ABSTRACT FROM AUTHOR]

Idiopathic pulmonary fibrosis (IPF) is a fatal disease with unknown cause and limited treatment options. Its mechanism needs to be further explored. Sirtuin2 (Sirt2), a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, has been proved to be involved in the fibrosis and inflammation in the liver, kidney and heart. In this study, we aimed to evaluate the role of Sirt2 in pulmonary fibrosis. We found that Sirt2 expression was upregulated in transforming growth factor- β 1 (TGF- β 1) treated human embryonic lung fibroblasts. Sirt2 inhibitor AGK2 or the knockdown of Sirt2 expression by targeting small interfering RNA (siRNA) suppressed the fibrogenic gene α -SMA and Fibronectin expression in TGF- β 1 treated fibroblasts and primary lung fibroblasts derived from patients with IPF. In addition, Sirt2 inhibition suppresses the phosphorylation of Smad2/3. Co-immunoprecipitation (Co-IP) showed that there is interaction between Sirt2 and Smad3 in the TGF- β 1 treated lung fibroblasts. In bleomycin-induced pulmonary fibrosis in mice, AGK2 treatment significantly mitigated the degree of fibrosis and decreased the phosphorylation of Smad2/3. These data suggest that Sirt2 may participate in the development of IPF via regulating the Smad2/3 pathway. Inhibition of Sirt2 would provide a novel therapeutic strategy for this disease. [ABSTRACT FROM AUTHOR]

Idiopathic pulmonary fibrosis (IPF) is a fatal disease with unknown cause and limited treatment options. Its mechanism needs to be further explored. Sirtuin2 (Sirt2), a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, has been proved to be involved in the fibrosis and inflammation in the liver, kidney and heart. In this study, we aimed to evaluate the role of Sirt2 in pulmonary fibrosis. We found that Sirt2 expression was upregulated in transforming growth factor-β1 (TGF-β1) treated human embryonic lung fibroblasts. Sirt2 inhibitor AGK2 or the knockdown of Sirt2 expression by targeting small interfering RNA (siRNA) suppressed the fibrogenic gene α-SMA and Fibronectin expression in TGF-β1 treated fibroblasts and primary lung fibroblasts derived from patients with IPF. In addition, Sirt2 inhibition suppresses the phosphorylation of Smad2/3. Co-immunoprecipitation (Co-IP) showed that there is interaction between Sirt2 and Smad3 in the TGF-β1 treated lung fibroblasts. In bleomycin-induced pulmonary fibrosis in mice, AGK2 treatment significantly mitigated the degree of fibrosis and decreased the phosphorylation of Smad2/3. These data suggest that Sirt2 may participate in the development of IPF via regulating the Smad2/3 pathway. Inhibition of Sirt2 would provide a novel therapeutic strategy for this disease.

Laminectomy is commonly performed to treat degenerative spinal diseases by reducing compression on the spinal cord and nerve roots. The postoperative epidural fibrosis and epidural adhesions may result in failed back surgery syndrome, which is characterized by the symptoms of lower back pain or leg pain. There is currently no satisfactory treatment for this complication. The pathological processes of epidural fibrosis and epidural adhesions are relevant to the proliferation of fibroblasts, transdifferentiation of fibroblasts into myofibroblasts, and the excessive deposition of extracellular matrix (ECM) protein. According to reports, transforming growth factor-β1 (TGF-β1) played a vital role in the development of fibrosis by promoting aforementioned processes. Decorin, an endogenous proteoglycan and natural inhibitor of TGF-β1, has exhibited prominent anti-fibrosis activity in various scar formation and fibrosis models of many organs. However, the preventive effect of decorin on epidural fibrosis and epidural adhesions requires further investigation. Here, we investigated the therapeutic effects and potential mechanisms of decorin on epidural fibrosis and epidural adhesions. Our results indicated that decorin could significantly suppress the TGF-β1-induced proliferation, transdifferentiation, and extracellular matrix production in primary fibroblasts. Furthermore, Smad2/3 signaling pathway had been demonstrated to be involved in the preventive effect of decorin. Moreover, administration of decorin in vivo could notably inhibit epidural fibrosis and epidural adhesions after laminectomy. To date, there is no approved therapy to target TGF-β1 for the treatment of epidural fibrosis and epidural adhesions after laminectomy. Our research proved the anti-fibrosis effect of decorin, which may provide an effective and promising treatment for epidural fibrosis and epidural adhesions.

Previous cDNA microarray results showed that MYH9 gene expression levels are increased in TGF-β1-stimulated lung fibroblast. Recently, our proteomic results revealed that the expression levels of MYH9 protein are notably upregulated in lung tissues of bleomycin-treated rats. However, whether MYH9 plays a critical role in the differentiation of fibroblast remains unclear. Herein, we demonstrated that TGF-β1 increased MYH9 expression, and siRNA-mediated knockdown of MYH9 and pharmacological inhibition of MYH9 ATPase activity remarkably repressed TGF-β1-induced lung fibroblast-to-myofibroblast differentiation. TGF-β1-stimulated MYH9 induction might be via ALK5/Smad2/3 pathway but not through noncanonical pathways, including p38 mitogen-activated kinase, and Akt pathways in lung fibroblasts. Our results showed that MYH9 inhibition suppressed TGF-β1-induced lung fibroblast-to-myofibroblast differentiation, which provides valuable information for illuminating the pathological mechanisms of lung fibroblast differentiation, and gives clues for finding new potential target for pulmonary fibrosis treatment.

Vascular smooth muscle cell (VSMC) proliferation and migration play a critical role in the development of arterial remodeling during various vascular diseases including atherosclerosis, hypertension, and related diseases. Luteolin is a food-derived flavonoid that exerts protective effects on cardiovascular diseases. Here, we investigated whether transforming growth factor-β receptor 1 (TGFBR1) signaling underlies the inhibitory effects of luteolin on VSMC proliferation and migration. We found that luteolin reduced the proliferation and migration of VSMCs, specifically A7r5 and HASMC cells, in a dose-dependent manner, based on MTS and EdU, and Transwell and wound healing assays, respectively. We also demonstrated that it inhibited the expression of proliferation-related proteins including PCNA and Cyclin D1, as well as the migration-related proteins MMP2 and MMP9, in a dose-dependent manner by western blotting. In addition, luteolin dose-dependently inhibited the phosphorylation of TGFBR1, Smad2, and Smad3. Notably, adenovirus-mediated overexpression of TGFBR1 enhanced TGFBR1, Smad2, and Smad3 activation in VSMCs and partially blocked the inhibitory effect of luteolin on TGFBR1, Smad2, and Smad3. Moreover, overexpression of TGFBR1 rescued the inhibitory effects of luteolin on the proliferation and migration of VSMCs. Additionally, molecular docking showed that this compound could dock onto an agonist binding site of TGFBR1, and that the binding energy between luteolin and TGFBR1 was -10.194 kcal/mol. Simulations of molecular dynamics showed that TGFBR1-luteolin binding was stable. Collectively, these data demonstrated that luteolin might inhibit VSMC proliferation and migration by suppressing TGFBR1 signaling.

Vascular smooth muscle cells (VSMCs) is a vital accelerator in the late phase of diabetic atherosclerosis, but the underlying mechanism remains unclear. The aim of our study was to investigate whether activin receptor-like kinase 7 (ALK7)-Smad2/3 pathway plays an important role in VSMC apoptosis of diabetic atherosclerosis. It was shown that ALK7 expression was obviously elevated in the aorta of ApoE -/- mice with type 2 diabetes mellitus. Inhibition of ALK7 expression significantly improved the stability of atherosclerotic plaques and reduced cell apoptosis. Further experiments showed that ALK7 knockdown stabilized atherosclerotic plaques by reducing VSMC apoptosis via activating Smad2/3. Our study uncovered the important role of ALK7-Smad2/3 signaling in VSMCs apoptosis, which might be a potential therapeutic target in diabetic atherosclerosis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Cao, Yuan, Dong, Liu, Liu, Zhai, Zhang, Liu, Tang, Wei and Chen.)

Previous cDNA microarray results showed that MYH9 gene expression levels are increased in TGF-β1-stimulated lung fibroblast. Recently, our proteomic results revealed that the expression levels of MYH9 protein are notably upregulated in lung tissues of bleomycin-treated rats. However, whether MYH9 plays a critical role in the differentiation of fibroblast remains unclear. Herein, we demonstrated that TGF-β1 increased MYH9 expression, and siRNA-mediated knockdown of MYH9 and pharmacological inhibition of MYH9 ATPase activity remarkably repressed TGF-β1-induced lung fibroblast-to-myofibroblast differentiation. TGF-β1-stimulated MYH9 induction might be via ALK5/Smad2/3 pathway but not through noncanonical pathways, including p38 mitogen-activated kinase, and Akt pathways in lung fibroblasts. Our results showed that MYH9 inhibition suppressed TGF-β1-induced lung fibroblast-to-myofibroblast differentiation, which provides valuable information for illuminating the pathological mechanisms of lung fibroblast differentiation, and gives clues for finding new potential target for pulmonary fibrosis treatment. [ABSTRACT FROM AUTHOR]

Vascular smooth muscle cell (VSMC) proliferation and migration play a critical role in the development of arterial remodeling during various vascular diseases including atherosclerosis, hypertension, and related diseases. Luteolin is a food-derived flavonoid that exerts protective effects on cardiovascular diseases. Here, we investigated whether transforming growth factor-β receptor 1 (TGFBR1) signaling underlies the inhibitory effects of luteolin on VSMC proliferation and migration. We found that luteolin reduced the proliferation and migration of VSMCs, specifically A7r5 and HASMC cells, in a dose-dependent manner, based on MTS and EdU, and Transwell and wound healing assays, respectively. We also demonstrated that it inhibited the expression of proliferation-related proteins including PCNA and Cyclin D1, as well as the migration-related proteins MMP2 and MMP9, in a dose-dependent manner by western blotting. In addition, luteolin dose-dependently inhibited the phosphorylation of TGFBR1, Smad2, and Smad3. Notably, adenovirus-mediated overexpression of TGFBR1 enhanced TGFBR1, Smad2, and Smad3 activation in VSMCs and partially blocked the inhibitory effect of luteolin on TGFBR1, Smad2, and Smad3. Moreover, overexpression of TGFBR1 rescued the inhibitory effects of luteolin on the proliferation and migration of VSMCs. Additionally, molecular docking showed that this compound could dock onto an agonist binding site of TGFBR1, and that the binding energy between luteolin and TGFBR1 was -10.194 kcal/mol. Simulations of molecular dynamics showed that TGFBR1-luteolin binding was stable. Collectively, these data demonstrated that luteolin might inhibit VSMC proliferation and migration by suppressing TGFBR1 signaling.