Mitochondrial oxidative damage and apoptosis induced by high glucose through Rho kinase signal pathway in renal tubular epithelial cells

Objective:To investigate the role of oxidative stress in human renal tubular epithelial cells(HK-2)induced by high glucose and the underlying signal pathway in vitro.Methods:MYPT1,pro-caspase-3,PGC-1α,and Drpl protein expressions were measured by Western blot.MnSOD2,Drp1 and PGC-1αmRNA expressions were detected by real time PCR.Results:Results showed that high glucose significantly up-regulated the protein expressions of MYPT1,pro-caspase-3 and the mRNA expression of MnSOD2 in HK-2 cells;while Rho kinase inhibitor fasudil and ROCK1 siRNA inhibited protein expressions of pro-caspase-3 and the mRNA expression of MnSOD2 in HK-2 cells induced by high glucose.Importantly,fasudil and ROCK1 siRNA markedly inhibited the expressions of mitochondrial motor proteins Drp1 and mitochondrial gene PGC-la in HK-2 cell=s induced by high glucose.Conclusions:Our findings suggest that Rho kinase signal pathway is involved in mitochondrial oxidative damage and apoptosis in high glucose-induced renal tubular epithelial cells by regulating mitochondrial motor proteins Drp1 and mitochondrial gene PGC-1α.Targeting Rho kinase signal pathway might be a potential strategy for the treatment of diabetic nephropathy.

Rho/Rock signal transduction pathway is required for MSC tenogenic differentiation

Mesenchymal stem cell （MSC）-based treatments have shown promise for improving tendon healing and repair. MSCs have the potential to differentiate into multiple lineages in response to select chemical and physical stimuli, including into tenocytes. Cell elongation and cytoskeletal tension have been shown to be instrumental to the process of MSC differentiation. Previous studies have shown that inhibition of stress fiber formation leads MSCs to default toward an adipogenic lineage, which suggests that stress fibers are required for MSCs to sense the environmental factors that can induce differentiation into tenocytes. As the Rho/ROCK signal transduction pathway plays a critical role in both stress fiber formation and in cell sensation, we examined whether the activation of this pathway was required when inducing MSC tendon differentiation using rope-like silk scaffolds. To accomplish this, we employed a loss-of-function approach by knocking out ROCK, actin and myosin （two other components of the pathway） using the specific inhibitors Y-27632, Latrunculin A and blebbistatin, respectively. We demonstrated that independently disrupting the cytoskeleton and the Rho/ ROCK pathway abolished the expression of tendon differentiation markers and led to a loss of spindle morphology. Together, these studies suggest that the tension that is generated by MSC elongation is essential for MSC teno-differentiation and that the Rho/ROCK pathway is a critical mediator of tendon differentiation on rope-like silk scaffolds.

加味小柴胡汤对哮喘大鼠Rho/Rcok信号传导通路的影响

目的观察加味小柴胡汤对哮喘大鼠气道重建中小G蛋白/Rho相关卷曲螺旋形成蛋白激酶(Rho/Rcok)信号通路的影响,探讨其作用机制。方法 60只雄性SD大鼠随机分为空白对照组、模型对照组、西药组、中药低剂量组、中药高剂量组、中西药组,每组10只。除空白对照组外,其余组别均采用以卵蛋白(OVA)致敏激发法制备大鼠哮喘模型,在OVA雾化激发的同时,各组分别给予相应药物灌胃治疗,西药组给予地塞米松注射液,中药低、高剂量组分别给予不同浓度(0.90 g生药/ml、1.80 g生药/ml)的加味小柴胡汤,中西药组给予地塞米松注射液+高剂量加味小柴胡汤。HE染色法观察大鼠肺组织病理学及嗜酸性粒细胞(EOS)计数变化,RT-PCR法测定肺组织RhoA、Rock2mRNA表达情况。结果 HE染色显示模型对照组大鼠肺组织中出现大量以EOS为主的炎症细胞浸润,支气管平滑肌增厚。上述病理改变在各药物治疗组中均有减轻,同时大鼠肺组织中EOS计数均较模型对照组有不同程度的减少(P<0.05,P<0.01)。RT-PCR法测定结果显示模型对照组肺组织中RhoA、Rock2 mRNA表达量明显高于空白对照组(P<0.05),各药物治疗组与模型对照组比较,肺组织中RhoA、Rock2 mRNA的表达明显下降(P<0.05,P<0.01)。结论加味小柴胡汤能够降低哮喘大鼠气道炎症细胞的浸润,对哮喘大鼠气道重塑中Rho/Rock信号通路有良好的调控作用。

Effect of electroacupuncture on the mRNA and protein expression of Rho-A and Rho-associated kinase Ⅱ in spinal cord injury rats

Electroacupuncture is beneficial for the recovery of spinal cord injury, but the underlying mechanism is unclear. The Rho/Rho-associated kinase（ROCK） signaling pathway regulates the actin cytoskeleton by controlling the adhesive and migratory behaviors of cells that could inhibit neurite regrowth after neural injury and consequently hinder the recovery from spinal cord injury. Therefore, we hypothesized electroacupuncture could affect the Rho/ROCK signaling pathway to promote the recovery of spinal cord injury. In our experiments, the spinal cord injury in adult Sprague-Dawley rats was caused by an impact device. Those rats were subjected to electroacupuncture at Yaoyangguan（GV3）, Dazhui（GV14）, Zusanli（ST36） and Ciliao（BL32） and/or monosialoganglioside treatment. Behavioral scores revealed that the hindlimb motor functions improved with those treatments. Real-time quantitative polymerase chain reaction, fluorescence in situ hybridization and western blot assay showed that electroacupuncture suppressed the m RNA and protein expression of Rho-A and Rho-associated kinase Ⅱ（ROCKⅡ） of injured spinal cord. Although monosialoganglioside promoted the recovery of hindlimb motor function, monosialoganglioside did not affect the expression of Rho-A and ROCKⅡ. However, electroacupuncture combined with monosialoganglioside did not further improve the motor function or suppress the expression of Rho-A and ROCKⅡ. Our data suggested that the electroacupuncture could specifically inhibit the activation of the Rho/ROCK signaling pathway thus partially contributing to the repair of injured spinal cord. Monosialoganglioside could promote the motor function but did not suppress expression of Rho A and ROCKⅡ. There was no synergistic effect of electroacupuncture combined with monosialoganglioside.

Effect of QingguanganⅡon Rho/ROCK associated factors in the retina of DBA/2J mice

Objective:The effect of QingguanganⅡon the transcription of RhoA mRNA,ROCK mRNA,Caspase-3 mRNA and Bcl-2 mRNA in the retina of DBA/2J mice was observed.Methods:Forty-eight DBA/2J mice were randomly divided into six groups:model groups,Qingguangan II decoction group,low concentration,medium concentration and high concentration group of Qingguangan II effective ingredient and positive control group(Yimaikang tablet group),and eight C57BL/6 mice were used as blank group,DBA/2J mice were fed until 38 weeks before forming a glaucoma model,The transcription of RhoA mRNA,ROCK mRNA,Caspase-3 mRNA and Bcl-2 mRNA in the retinal of DBA/2J mice was detected using real-time fluorescence quantitative PCR(Quantitative Real-time PCR)after 4 weeks of intervention.Results:Four weeks after the intervention,In the transcription of the RhoA mRNA,ROCK mRNA and the Caspase-3 mRNA,Compared to the blank groups,Relative expression was increased in the other 6 groups,There are statistical differences in the model group,Yimaikang tablet group and low concentration group(P<0.05);In comparison to the model groups,The other 6 groups were lower than the model group,Among them,there are statistical differences between the effective groups of Qingguangan II decoction and high concentration group of Qingguangan II effective ingredient in RhoA mRNA transcription(P<0.05);In the transcription of the ROCK mRNA and the Caspase-3 mRNA,Statistics have differences between the model group and the effective component of the medium and high concentration group(P<0.05);In the Bcl-2 mRNA transcription,Compare them to blank groups,Relexpression expression decreased in the other 6 groups,Statistics have differences between model group,Qingguangan II decoction group and low concentration groups(P<0.05);The relative expression of Bcl-2 mRNA in high concentration group of effective component is higher than that of the model group,There are differences in statistics(P<0.05).Conclusion:The high concentration of QingguanganⅡprescription probably attenuated Caspase-3 transcription in retinal ganglion cells by inhibiting the Rho/ROCK signaling pathway and activated Bcl-2 expression by inhibiting ROCK signaling,which attenuated apoptosis in retinal ganglion cells.

Houshiheisan and its components promote axon regeneration after ischemic brain injury

Houshiheisan,a classic prescription in traditional Chinese medicine,contains Flos Chrysanthemi,Radix Saposhnikoviae,Ramulus Cinnamomi,Rhizoma Chuanxiong,Radix et Rhizoma Asari,Radix Platycodonis,Rhizoma Atractylodis macrocephalae,Poria,Rhizoma Zingiberis,Radix Angelicae sinensis,Radix et Rhizoma Ginseng,Radix Scutellariae and Concha Ostreae.According to traditional Chinese medicine theory,Flos Chrysanthemi,Radix Saposhnikoviae,Ramulus Cinnamomi,Rhizoma Chuanxiong,Radix et Rhizoma Asari and Radix Platycodonis are wind-dispelling drugs;Rhizoma Atractylodis macrocephalae,Poria,Rhizoma Zingiberis,Radix Angelicae sinensis and Radix et Rhizoma Ginseng are deficiency-nourishing drugs.A large number of randomized controlled trials have shown that Houshiheisan is effective in treating stroke,but its mechanism of action is unknown.Axonal remodeling is an important mechanism in neural protection and regeneration.Therefore,this study explored the effect and mechanism of action of Houshiheisan on the repair of axons after cerebral ischemia.Rat models of focal cerebral ischemia were established by ligating the right middle cerebral artery.At 6 hours after model establishment,rats were intragastrically administered 10.5 g/kg Houshiheisan or 7.7 g/kg wind-dispelling drug or 2.59 g/kg deficiency-nourishing drug.These medicines were intragastrically administered as above every 24 hours for 7 consecutive days.Houshiheisan,and its wind-dispelling and deficiency-nourishing components reduced the neurological deficit score and ameliorated axon and neuron lesions after cerebral ischemia.Furthermore,Houshiheisan,and its wind-dispelling and deficiency-nourishing components decreased the expression of proteins that inhibit axonal remodeling：amyloid precursor protein,neurite outgrowth inhibitor protein A（Nogo-A）,Rho family small GTPase A（Rho A） and Rho-associated kinase 2（Rock2）,and increased the expression of growth associated protein-43,microtubule-associated protein-2,netrin-1,Ras-related C3 botulinum toxin substrate 1（Rac1） and cell division cycle 42（Cdc42）.The effect of Houshiheisan was stronger than wind-dispelling drugs or deficiency-nourishing drugs alone.In conclusion,Houshiheisan,and wind-dispelling and deficiency-nourishing drugs promote the repair of axons and nerve regeneration after cerebral ischemia through Nogo-A/Rho A/Rock2 and Netrin-1/Rac1/Cdc42 signaling pathways.These effects are strongest with Houshiheisan.