Baicalin attenuates transforming growth factor-β1-induced human pulmonary artery smooth muscle cell proliferation and phenotypic switch by inhibiting hypoxia inducible factor-1α and aryl hydrocarbon receptor expression

2014 ◽  
Vol 66 (10) ◽  
pp. 1469-1477 ◽  
Author(s):  
Shian Huang ◽  
Puwen Chen ◽  
Xiaorong Shui ◽  
Yuan He ◽  
Heyong Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Transforming Growth Factor ◽  
Hypoxia Inducible Factor ◽  
Transforming Growth Factor Β1 ◽  
Receptor Expression ◽  
Phenotypic Switch ◽  
Aryl Hydrocarbon ◽  
Pulmonary Artery Smooth Muscle ◽  
Human Pulmonary Artery

Transforming growth factor-β1 induces Nox4 NAD(P)H oxidase and reactive oxygen species-dependent proliferation in human pulmonary artery smooth muscle cells

2006 ◽  
Vol 290 (4) ◽  
pp. L661-L673 ◽  
Author(s):  
Anne Sturrock ◽  
Barbara Cahill ◽  
Kimberly Norman ◽  
Thomas P. Huecksteadt ◽  
Kenneth Hill ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Smooth Muscle ◽  
Map Kinases ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Ros Production ◽  
Oxygen Species ◽  
Pulmonary Artery Smooth Muscle ◽  
Human Pulmonary Artery ◽  
Tgf Β1

Transforming growth factor-β1 (TGF-β1) is abundantly expressed in pulmonary hypertension, but its effect on the pulmonary circulation remains unsettled. We studied the consequences of TGF-β1 stimulation on freshly isolated human pulmonary artery smooth muscle cells (HPASMC). TGF-β1 initially promoted differentiation, with upregulated expression of smooth muscle contractile proteins. TGF-β1 also induced expression of Nox4, the only NAD(P)H oxidase membrane homolog found in HPASMC, through a signaling pathway involving Smad 2/3 but not mitogen-activated protein (MAP) kinases. TGF-β1 likewise increased production of reactive oxygen species (ROS), an effect significantly reduced by the NAD(P)H oxidase flavoprotein inhibitor diphenylene iodonium (DPI) and by Nox4 siRNAs. In the absence of TGF-β1, Nox4 was present in freshly cultured cells but progressively lost with each passage in culture, paralleling a decrease in ROS production by HPASMC over time. At a later time point (72 h), TGF-β1 promoted HPASMC proliferation in a manner partially inhibited by Nox4 small interfering RNA and dominant negative Smad 2/3, indicating that TGF-β1 stimulates HPASMC growth in part by a redox-dependent mechanism mediated through induction of Nox4. HPASMC activation of the MAP kinases ERK1/2 was reduced by the NAD(P)H oxidase inhibitors DPI and 4-(2-aminoethyl)benzenesulfonyl fluoride, suggesting that TGF-β1 may facilitate proliferation by upregulating Nox4 and ROS production, with transient oxidative inactivation of phosphatases and augmentation of growth signaling cascades. These findings suggest that Nox4 is the relevant Nox homolog in HPASMC. This is the first observation that TGF-β1 regulates Nox4, with important implications for mechanisms of pulmonary vascular remodeling.

scholarly journals NOX4 mediates hypoxia-induced proliferation of human pulmonary artery smooth muscle cells: the role of autocrine production of transforming growth factor-β1 and insulin-like growth factor binding protein-3

2009 ◽  
Vol 296 (3) ◽  
pp. L489-L499 ◽  
Author(s):  
Saleh Ismail ◽  
Anne Sturrock ◽  
Ping Wu ◽  
Barbara Cahill ◽  
Kimberly Norman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Pulmonary Artery ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Pulmonary Artery Smooth Muscle ◽  
Human Pulmonary Artery ◽  
Tgf Β1 ◽  
Igfbp 3

Persistent hypoxia can cause pulmonary arterial hypertension that may be associated with significant remodeling of the pulmonary arteries, including smooth muscle cell proliferation and hypertrophy. We previously demonstrated that the NADPH oxidase homolog NOX4 mediates human pulmonary artery smooth muscle cell (HPASMC) proliferation by transforming growth factor-β1 (TGF-β1). We now show that hypoxia increases HPASMC proliferation in vitro, accompanied by increased reactive oxygen species generation and NOX4 gene expression, and is inhibited by antioxidants, the flavoenzyme inhibitor diphenyleneiodonium (DPI), and NOX4 gene silencing. HPASMC proliferation and NOX4 expression are also observed when media from hypoxic HPASMC are added to HPASMC grown in normoxic conditions, suggesting autocrine stimulation. TGF-β1 and insulin-like growth factor binding protein-3 (IGFBP-3) are both increased in the media of hypoxic HPASMC, and increased IGFBP-3 gene expression is noted in hypoxic HPASMC. Treatment with anti-TGF-β1 antibody attenuates NOX4 and IGFBP-3 gene expression, accumulation of IGFBP-3 protein in media, and proliferation. Inhibition of IGFBP-3 expression with small interfering RNA (siRNA) decreases NOX4 gene expression and hypoxic proliferation. Conversely, NOX4 silencing does not decrease hypoxic IGFBP-3 gene expression or secreted protein. Smad inhibition does not but the phosphatidylinositol 3-kinase (PI3K) signaling pathway inhibitor LY-294002 does inhibit NOX4 and IGFBP-3 gene expression, IGFBP-3 secretion, and cellular proliferation resulting from hypoxia. Immunoblots from hypoxic HPASMC reveal increased TGF-β1-mediated phosphorylation of the serine/threonine kinase (Akt), consistent with hypoxia-induced activation of PI3K/Akt signaling pathways to promote proliferation. We conclude that hypoxic HPASMC produce TGF-β1 that acts in an autocrine fashion to induce IGFBP-3 through PI3K/Akt. IGFBP-3 increases NOX4 gene expression, resulting in HPASMC proliferation. These observations add to our understanding hypoxic pulmonary vascular remodeling.

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