Baicalin alleviates adriamycin-induced focal segmental glomerulosclerosis and proteinuria by inhibiting the Notch1-Snail axis mediated podocyte EMT.

Podocyte injury is an early event and core in the development of focal segmental glomerular sclerosis (FSGS) that induces poor prognosis. Epithelial-mesenchymal transition (EMT) as a response of podocyte to injury leads to podocyte depletion and proteinuria. The abnormally reactivated NOTCH pathway may be involved in podocyte EMT. Baicalin, as a natural flavonoid compound, had significant inhibitory activity on tissue fibrosis and tumor cell invasion. However, its potential role and molecular mechanisms to injured podocyte in FSGS are little known. Here we found that baicalin could inhibit podocyte EMT markers expression and cell migration induced by TGF-ß1, accompanied by the up-regulated expression of slit diaphragm (SD) proteins and cell-cell adhesion molecule. Further investigation revealed that EMT inhibition of baicalin on injured podocyte is mainly mediated by the reduction of notch1 activation and its downstream Snail expression. Using the adriamycin-induced FSGS model, we determined that baicalin suppresses the Notch1-Snail axis activation in podocytes, relieves glomerulus structural disruption and dysfunction, and reduces proteinuria. Altogether, these findings suggest that baicalin is a novel renoprotective agent against podocyte EMT in FSGS and indicate its underlying mechanism that involves in negative regulation of the Notch1-Snail axis.

Oroxylin A Reduces Vasoconstriction in Rat Aortic Rings through Promoting NO Production and NOS Protein Expression via Estrogen Receptor Signal Pathway.

Oroxylin A, a flavonoid, is naturally produced in many medicinal plants. Our previous study identified it as a phytoestrogen. Based on this, the present study investigated its vasoconstriction reducing effects and whether the action was mediated by the estrogen receptor (ER) signal pathway. Long-term in vitro treatment with oroxylin A reduced Ach-induced vasorelaxation and NE-mediated or KCl-mediated contractile responses in rat aortic rings. These effects were interfered by an ER inhibitor ICI 182,780. Rat cardiac microvascular endothelial cells (CMECs) and aortic vascular smooth muscle cells (VSMCs) were used to study the possible underlying mechanisms. Oroxylin A activated the ER signal pathway. In CMECs, it increased NO production and eNOS protein expression. In VSMCs, it promoted NO production and iNOS protein expression. These effects were also inhibited by ICI 182,780. Besides, oroxylin A stimulated ERα and ERß protein expression in CMECs and VSMCs. All these findings suggest that the ER signal pathway takes part in the vasoconstriction reducing effects of oroxylin A.

Formononetin attenuates atherosclerosis via regulating interaction between KLF4 and SRA in apoE-/- mice.

Background and Purpose: Atherosclerosis is an underlying cause of coronary heart disease. Foam cell, a hallmark of atherosclerosis, is prominently derived from monocyte-differentiated macrophage, and vascular smooth muscle cells (VSMCs) through unlimitedly phagocytizing oxidized low-density lipoprotein (oxLDL). Therefore, the inhibition of monocyte adhesion to endothelium and uptake of oxLDL might be a breakthrough point for retarding atherosclerosis. Formononetin, an isoflavone extracted from Astragalus membranaceus, has exhibited multiple inhibitory effects on proatherogenic factors, such as obesity, dyslipidemia, and inflammation in different animal models. However, its effect on atherosclerosis remains unknown. In this study, we determined if formononetin can inhibit atherosclerosis and elucidated the underlying molecular mechanisms. Methods: ApoE deficient mice were treated with formononetin contained in high-fat diet for 16 weeks. After treatment, mouse aorta, macrophage and serum samples were collected to determine lesions, immune cell profile, lipid profile and expression of related molecules. Concurrently, we investigated the effect of formononetin on monocyte adhesion, foam cell formation, endothelial activation, and macrophage polarization in vitro and in vivo. Results: Formononetin reduced en face and aortic root sinus lesions size. Formononetin enhanced lesion stability by changing the composition of plaque. VSMC- and macrophage-derived foam cell formation and its accumulation in arterial wall were attenuated by formononetin, which might be attributed to decreased SRA expression and reduced monocyte adhesion. Formononetin inhibited atherogenic monocyte adhesion and inflammation. KLF4 negatively regulated the expression of SRA at transcriptional and translational level. Conclusions: Our study demonstrate that formononetin can substantially attenuate the development of atherosclerosis via regulation of interplay between KLF4 and SRA, which suggests the formononetin might be a novel therapeutic approach for inhibition of atherosclerosis.

Formononetin ameliorates cholestasis by regulating hepatic SIRT1 and PPARα.

Cholestasis, which is characterized by bile acid (BA) overload within the hepatocytes, is a major contributor to liver injury. The dysregulation of bile acid homeostasis, such as excessive bile acid synthesis and defected secretion, leads to intracellular retention of hydrophobic bile acid which undermines the physiological function of hepatocytes. Cholestasis can further develop into hepatic fibrosis and cirrhosis, and eventually life-threating liver failure. In the liver, BA-activated FXR can reduce hepatic BA concentration by negative feedback regulation. Clinically, FXR and PPARα are the pharmacological targets of obeticholic acid and fenofibrate for the treatment of primary biliary cirrhosis, respectively. Formononetin, a natural isoflavone compound, exerts beneficial effects in various biological processes, such as anti-inflammation, anti-tumor. However, the role of formononetin in bile acid metabolism remains unclear. Herein, we show that formononetin improves hepatic/systemic bile acid metabolism and protects against ANIT-induced liver injury. Mechanistically, formononetin improves the genes profile orchestrating bile acid homeostasis through modulating SIRT1-FXR signaling pathway. Moreover, formononetin attenuated ANIT-induced inflammatory response by inactivating JNK inflammation pathway in PPARα dependent manner. Taken together, our study demonstrates that formononetin ameliorates hepatic cholestasis by upregulating expression of SIRT1 and activating PPARα, which is an important anti-cholestatic mechanism of formononetin.

Vasodilatory Effect of Wogonin on the Rat Aorta and Its Mechanism Study.

Wogonin, a natural flavonoid, is one of the bioactive compounds of the medicinal herb Eucommia ulmoides OLIV. widely used in southeastern Asia for treating hypertension. However, the molecular mechanisms for the therapeutic benefits remain largely unclear. The present study investigated the vasodilatory effect of wogonin and its possible mechanisms. The flavonoid (0.1-100 µM) caused concentration-dependent relaxations in endothelium-intact aortic rings precontracted with norepinephrine (NE, 1 µM) or potassium chloride (KCl, 60 mM). Preincubation with wogonin (10, 100 µM) for 20 min significantly inhibited the contractile responses to NE (0.1, 1, 10 µM) or KCl (7.5, 15, 30, 60 mM). Relaxant responses to wogonin were not inhibited by N(G)-nitro-L-arginine methylester (100 µM) or endothelial denudation. In a Ca(2+)-free Krebs' solution, wogonin not only blocked Ca(2+) influx-dependent vasoconstriction by either NE (1 µM) or KCl (100 mM), but also inhibited NE (1 µM)-induced tonic contraction, which is dependent on intracellular Ca(2+) release. Wogonin also suppressed the elevation of [Ca(2+)]i induced by KCl (60 mM) after exhausting the calcium store in sarcoplasmic and endoplasmic reticula with thapsigargin (1 µM) or by ATP (100 µM) in primary vascular smooth muscle cells. These findings suggest that wogonin-induced responses are mainly due to the inhibition of both intracellular Ca(2+) release and extracellular Ca(2+) influx.

[Vasodilator effect of oroxylin A on thoracic aorta isolated from rats].

OBJECTIVE: To investigate the vasodilator effect and the endothelium-dependent mechanism of oroxylin A in thoracic aorta isolated from rats. METHODS: Thoracic aorta was isolated from Wistar rats. After pretreatment with norepinephrine or KCl, the effects of oroxylin A at different concentrations were detected on isolated vascular rings prepared from rats' thoracic aorta. The response of thoracic aortic ring was evaluated in the presence and absence of endothelium, and NG-nitro-L-arginine methyl ester (L-NAME), a specific inhibitor of nitric oxide synthase. RESULTS: Oroxylin A (10 and 100 µmol/L) caused vasodilation on endothelium-intact aortic rings pretreated with norepinephrine (1 µmol/L) and KCl (60 mmol/L) compared with the control (P<0.05, P<0.01). The vasodilation function of 10 and 100 µmol/L oroxylin A on the endothelium-denuded aorta rings was significantly lower than that on the endothelium-intact aorta rings (P<0.05, P<0.01). L-NAME pretreatment significantly attenuated the effect of 100 µmol/L oroxylin A on endothelium-intact aorta rings (P<0.05, P<0.01). CONCLUSION: Oroxylin A can induce the relaxation of the aorta ring in endothelium-dependent manner. Nitric oxide may be involved in the endothelium-dependent effect of oroxylin A.