Up-regulation of paired-related homeobox 2 promotes cardiac fibrosis in mice following myocardial infarction by targeting of Wnt5a.

Cardiac fibrosis is a key factor to determine the prognosis in patient with myocardial infarction (MI). The aim of this study is to investigate whether the transcriptional factor paired-related homeobox 2 (Prrx2) regulates Wnt5a gene expression and the role in myocardial fibrosis following MI. The MI surgery was performed by ligation of left anterior descending coronary artery. Cardiac remodelling was assessed by measuring interstitial fibrosis performed with Masson staining. Cell differentiation was examined by analysis the expression of alpha-smooth muscle actin (α-SMA). Both Prrx2 and Wnt5a gene expressions were up-regulated in mice following MI, accompanied with increased mRNA and protein levels of α-SMA, collagen I and collagen III, compared to mice with sham surgery. Adenovirus-mediated gene knock down of Prrx2 increased survival rate, alleviated cardiac fibrosis, decreased infarction sizes and improved cardiac functions in mice with MI. Importantly, inhibition of Prrx2 suppressed ischaemia-induced Wnt5a gene expression and Wnt5a signalling. In cultured cardiac fibroblasts, TGF-ß increased gene expressions of Prrx2 and Wnt5a, and induced cell differentiations, which were abolished by gene silence of either Prrx2 or Wnt5a. Further, overexpression of Prrx2 or Wnt5a mirrored the effects of TGF-ß on cell differentiations of cardiac fibroblasts. Gene silence of Wnt5a also ablated cell differentiations induced by Prrx2 overexpression in cardiac fibroblasts. Mechanically, Prrx2 was able to bind with Wnt5a gene promoter to up-regulate Wnt5a gene expression. In conclusions, targeting Prrx2-Wnt5a signalling should be considered to improve cardiac remodelling in patients with ischaemic heart diseases.

Traditional Chinese medicine Ka-Sai-Ping suppresses the growths of gastric cancers via induction of autophagy.

Traditional Chinese medication is increasingly used to treat a wide range of human chronic diseases like cardiovascular diseases and cancers. This study was designed to explore whether ka-sai-ping (KSP), a novel traditional Chinese medicine developed by us, prevents gastric cancer growths and to investigate the underlying mechanism. The xenograft model of mouse gastric cancer was established by injecting MFCs into nude mouse subcutaneously. Cell autophagy was assessed by MDC staining. Lysosome and mitochondria were detected by Lyso-Tracker Red and Mito-Traker Green staining. Incubation of cultured mouse gastric cancer cell line MFCs with KSP for 48 hours, concentration-dependently reduced cell survivals and activated autophagy, which were accompanied with damaged lysosomes and mitochondria. In vivo studies indicated that KSP therapy (20 ml/kg/day) for two weeks suppressed the growth of gastric cancer, increased the protein levels of LC3-II, beclin-1, cathepsin L, bcl-2, p53, and capase-3 in tumor tissues from the xenograft model of mouse gastric cancer. Importantly, all these effects induced by KSP were abolished by co-administration of autophagy inhibitor 3-MA. In conclusion, KSP activates cell autophagy to suppress gastric cancer growths. Clinically, KSP is potentially considered as a medicine to treat patients with gastric cancer.

Berberine promotes ischemia-induced angiogenesis in mice heart via upregulation of microRNA-29b.

BACKGROUND: Berberine has several preventive effects on cardiovascular diseases. Increased expression of miR-29b has been reported to attenuate cardiac remodeling after myocardial infarction (MI). We hypothesized that berberine via an miR-29b-dependent mechanism promotes angiogenesis and improves heart functions in mice after MI. METHODS: The MI model was established in mice by ligation of left anterior descending coronary artery. The expression of miR-29b was examined by RT-qPCR. Angiogenesis was assessed by immunohistochemistry. RESULTS: Berberine increased miR-29b expression and promoted cell proliferations and migrations in cultured endothelial cells, which were abolished by miR-29b antagomir or AMP-activated protein kinase inhibitor compound C. In mice following MI, administration of berberine significantly increased miR-29b expressional level, promoted angiogenesis, reduced infarct size, and improved heart functions after 14 postoperative days. Importantly, these in vivo effects of berberine were ablated by antagonism of miR-29b. CONCLUSION: Berberine via upregulation of miR-29b promotes ischemia-induced angiogenesis and improves heart functions.

Hyperglycemia via activation of thromboxane A2 receptor impairs the integrity and function of blood-brain barrier in microvascular endothelial cells.

Diabetes is one of high risk factors for cardio- and cerebra-vascular diseases, including stroke, atherosclerosis and hypertension. This study was conducted to elucidate whether and how thromboxane receptor (TPr) activation contributes to blood-brain barrier (BBB) dysfunction in diabetes. Human brain microvascular endothelial cells (HBMECs) were cultured. The levels of phosphorylated endothelial nitric oxide synthase (eNOS) at Ser1177 (p-eNOS) and Akt at Ser473 (p-Akt) were assayed by western blot. Exposure of HBMECs to either high glucose (HG) or thromboxane A2 (TxA2) mimetic U46619, significantly reduced p-eNOS and p-Akt. These effects were abolished by pharmacological or genetic inhibitors of TPr. HG/U46619-induced suppressions of eNOS and Akt phosphorylation were accompanied by upregulation of PTEN and Ser380/Thr382/383 PTEN phosphorylation. PTEN-specific siRNA restored Akt-eNOS signaling in the face of TPr activation or HG. The small GTPase, Rho, was also activated by HG stimulation, and pretreatment of HBMECs with Y27632, a Rho-associated kinase (ROCK) inhibitor, rescued HG-impaired Akt-eNOS signaling. In STZ-injected rats, we found that hyperglycemia dramatically increased the levels of PTEN and PTEN-Ser380/Thr382/383 phosphorylation, reduced both levels of p-eNOS and p-Akt, and disrupted BBB function assayed by Evans blue staining, which were abolished by SQ29548 treatment. We conclude that hyperglycemia activates thromboxane A2 receptor to impair the integrity and function of blood-brain barrier via the ROCK-PTEN-Akt-eNOS pathway.

Traditional Chinese medicine xin-mai-jia recouples endothelial nitric oxide synthase to prevent atherosclerosis in vivo.

Endothelial dysfunction, which is caused by endothelial nitric oxide synthase (eNOS) uncoupling, is an initial step in atherosclerosis. This study was designed to explore whether Chinese medicine xin-mai-jia (XMJ) recouples eNOS to exert anti-atherosclerotic effects. Pretreatment of XMJ (25, 50, 100 µg/ml) for 30 minutes concentration-dependently activated eNOS, improved cell viabilities, increased NO generations, and reduced ROS productions in human umbilical vein endothelial cells incubated with H2O2 for 2 hours, accompanied with restoration of BH4. Importantly, these protective effects produced by XMJ were abolished by eNOS inhibitor L-NAME or specific eNOS siRNA in H2O2-treated cells. In ex vivo experiments, exposure of isolated aortic rings from rats to H2O2 for 6 hours dramatically impaired acetylcholine-induced vasorelaxation, reduced NO levels and increased ROS productions, which were ablated by XMJ in concentration-dependent manner. In vivo analysis indicated that administration of XMJ (0.6, 2.0, 6.0 g/kg/d) for 12 weeks remarkably recoupled eNOS and reduced the size of carotid atherosclerotic plaque in rats feeding with high fat diet plus balloon injury. In conclusion, XMJ recouples eNOS to prevent the growth of atherosclerosis in rats. Clinically, XMJ is potentially considered as a medicine to treat patients with atherosclerosis.

Pravastatin activates activator protein 2 alpha to augment the angiotensin II-induced abdominal aortic aneurysms.

We have previously reported that activation of AMP-activated kinase alpha 2 (AMPKα2) by nicotine or angiotensin II (AngII) instigates formation of abdominal aortic aneurysms (AAA) in Apoe-/- mice. Statins, used to treat hyperlipidemia widely, activate AMPK in vascular cells. We sought to examine the effects of pravastatin on AAA formation and uncover the molecular mechanism. The AAA model was induced by AngII and evaluated by incidence, elastin degradation, and maximal abdominal aortic diameter in Apoe-/- mice. The phosphorylated levels of AMPKα2 and activator protein 2 alpha (AP-2α) were examined in cultured vascular smooth muscle cells (VSMCs) or in mice. We observed that pravastatin (50 mg/kg/day, 8 weeks) remarkably increased the AngII-induced AAA incidence in mice. In VSMCs, pravastatin increased the levels of pAMPK, pAP-2α, and MMP2 in both basal and AngII-stressed conditions, which were abolished by tempol and compound C. Pravastatin-upregulated MMP2 was abrogated by AMPKα2 or AP-2α siRNA. Lentivirus-mediated gene silence of AMPKα2 or AP-2α abolished pravastatin-worsened AAA formations in AngII-infused Apoe-/- mice. Clinical investigations demonstrated that both AMPKα2 and AP-2α phosphorylations were increased in AAA patients or human subjects taking pravastatin. In conclusion, pravastatin promotes AAA formation through AMPKα2-dependent AP-2α activations.

Activation of AMPK improves lipopolysaccharide-induced dysfunction of the blood-brain barrier in mice.

PRIMARY OBJECTIVE: Lipopolysaccharide (LPS) is known to alter the integrity of the blood-brain barrier (BBB) in sepsis, although the underlying mechanism remains unknown. The aim of this study was to elucidate the molecular mechanisms underlying disruption of the BBB in LPS-induced sepsis. RESEARCH DESIGN: Both in vitro and in vivo experiments were designed to test the role of AMP-activated protein kinase (AMPK) in LPS-induced BBB dysfunction. METHODS AND PROCEDURES: Human brain microvascular endothelial cells (HBMECs) were cultured. The protein expressions were detected by western blot. BBB integrity was determined by Evans Blue. MAIN OUTCOMES AND RESULTS: LPS (1 µg ml(-1)) dramatically increased the permeability of the BBB and the ROS productions, as well as reducing the expression levels of occludin and claudin-5 in cultured HBMECs. Inhibition of NAD(P)H oxidase by apocynin or up-regulation of AMPK reversed the LPS-induced abnormities in HBMECs. In LPS-induced sepsis in mice, it was found that LPS dramatically increased NAD(P)H oxidase protein expressions and ROS productions in the brain and disrupted BBB function assayed by Evans blue staining, which were abolished by AICAR treatment. CONCLUSIONS: It is concluded that AMPK activation improves the functions of the BBB impaired by LPS through suppression of NAD(P)H oxidase-derived ROS in mice.