Electroacupuncture reduces apoptotic index and inhibits p38 mitogen-activated protein kinase signaling pathway in the hippocampus of rats with cerebral ischemia/reperfusion injury

Electroacupuncture attenuates cerebral hypoxia and neuronal apoptosis induced by cerebral ischemia/reperfusion injury.To further identify the involved mechanisms,we assumed that electroacupuncture used to treat cerebral ischemia/reperfusion injury was associated with the p38 mitogen-activated protein kinase（MAPK） signaling pathway.We established rat models of cerebral ischemia/reperfusion injury using the modified Zea-Longa＇s method.At 30 minutes before model establishment,p38 MAPK blocker SB20358 was injected into the left lateral ventricles.At 1.5 hours after model establishment,electroacupuncture was administered at acupoints of Chize（LU5）,Hegu（LI4）,Zusanli（ST36）,and Sanyinjiao（SP6） for 20 minutes in the affected side.Results showed that the combination of EA and SB20358 injection significantly decreased neurologic impairment scores,but no significant differences were determined among different interventional groups.Hematoxylin-eosin staining also showed reduced brain tissue injuries.Compared with the SB20358 group,the cells were regularly arranged,the structures were complete,and the number of viable neurons was higher in the SB20358 ＋ electroacupuncture group.Terminal deoxynucleotidyl transferase（Td T）-mediated d UTP nick-end labeling assay showed a decreased apoptotic index in each group,with a significant decrease in the SB20358 ＋ electroacupuncture group.Immunohistochemistry revealed reduced phosphorylated p38 expression at 3 days in the electroacupuncture group and SB20358 ＋ electroacupuncture group compared with the ischemia/reperfusion group.There was no significant difference in phosphorylated p38 expression between the ischemia/reperfusion group and SB20358 group.These findings confirmed that the electroacupuncture effects on mitigating cerebral ischemia/reperfusion injury are possibly associated with the p38 MAPK signaling pathway.A time period of 3 days could promote the repair of ischemic cerebral nerves.

Physiological roles of mitogen-activated-protein-kinase-activated p38-regulated/activated protein kinase

Mitogen-activated protein kinases(MAPKs)are a family of proteins that constitute signaling pathways involved in processes that control gene expression,cell division, cell survival,apoptosis,metabolism,differentiation and motility.The MAPK pathways can be divided into conventional and atypical MAPK pathways.The first group converts a signal into a cellular response through a relay of three consecutive phosphorylation events exerted by MAPK kinase kinases,MAPK kinase,and MAPK.Atypical MAPK pathways are not organized into this three-tiered cascade.MAPK that belongs to both conventional and atypical MAPK pathways can phosphorylate both non-protein kinase substrates and other protein kinases.The latter are referred to as MAPK-activated protein kinases.This review focuses on one such MAPK-activated protein kinase,MAPK-activated protein kinase 5(MK5)or p38-regulated/activated protein kinase(PRAK).This protein is highly conserved throughout the animal kingdom and seems to be the target of both conventional and atypical MAPK pathways.Recent findings on the regulation of the activity and subcellular localization,bona fide interaction partners and physiological roles of MK5/PRAK are discussed.

Hippocampal activation of c-Jun N-terminal kinase,protein kinase B,and p38 mitogen-activated protein kinase in a chronic stress rat model of depression

Recent studies have shown that varied stress stimuli activate c-Jun N-terminal kinase （JNK）, protein kinase B （Akt）, and p38 mitogen-activated protein kinase （p38） signal transduction pathway, and also regulate various apoptotic cascades. JNK and p38 promote apoptosis, but Akt protects against apoptosis, in hippocampal neurons. However, changes in the transduction pathway in different regions of brain tissues in a chronic stress rat model of depression remain poorly understood. Results from this study showed that JNK phosphorylation levels were significantly greater in the stress group hippocampus compared with the control group （P 〈 0.05）. No significant difference in JNK phosphorylation levels was detected in the rat cerebral cortex between stress and control groups, and no significant difference in Akt and p38 phosphorylation levels was detected in the rat hippocampus and cerebral cortex between stress and control groups （P 〉 0.05）. These results suggested that the JNK signal pathway is activated by JNK phosphorylation and participates in pathophysiological changes in rat models of depression.

锰诱导PC12细胞凋亡与p-38MAPKs的关系

目的 以鼠嗜铬神经瘤细胞 (PC12 )为模型 ,筛选锰对神经细胞增殖抑制作用的时间及剂量 ,观察细胞形态学、细胞周期和生化指标改变与丝裂原活化蛋白激酶 (p38MAPKs)活化表达间的关系。方法 用 2 0 0 ,4 0 0 ,6 0 0 ,80 0μmol/LMnCl2 的培养液 ,分别作用对数生长期PC12细胞 1,2 ,3,4d后 ,用噻唑蓝比色 (MTT)筛选锰的细胞毒性剂量 ;流式细胞仪检测细胞周期分布 ;透射电镜观察细胞形态学变化 ;琼脂糖凝胶电泳检测MnCl2 对PC12细胞基因组DNA的影响。蛋白印迹 (western -blot)法检测 p -p38。结果 MTT实验结果显示 ,2 0 0～ 80 0 μmol/LMnCl2 作用 1,2 ,3,4d对PC12有显著的抑制作用 ,呈剂量和时间依赖趋势 ,6 0 0 μmol/LMnCl2 作用 4d对PC12的抑制率可达 5 0 %以上。流式细胞仪检测实验表明 :6 0 0 μmol/LMnCl2 作用 4d将PC12细胞周期阻滞在S期 ,诱导细胞凋亡 ,与电镜结果一致 ,同样条件下细胞DNA碎片化。Western -blot实验显示 6 0 0 μmol/LMnCl2 作用 1,2 ,3,4dp -p38逐渐升高 ,3d时较对照组增加 6 6倍 (n =3,P <0 0 5 ) ,2 0 0 ,4 0 0 ,6 0 0 μmol/LMnCl2 作用 4d时 ,磷酸化蛋白 38(p - p38)也逐渐升高 ,4 0 0 μmol/LMnCl2 作用 4d时较对照组升高 4 7倍 (n =3,P <0 0 5 )。结论 锰通过MEK3/

The binding of actin to p38 MAPK and inhibiting its kinase activity in vitro

p38 MAP kinase mediates a signal pathway that is involved in many physiological and pathological processes such as inflammation, cellular stress, apoptosis, cell cycle and growth, ischemia/re-perfusion, and myocardium hypertrophy. To determine the molecular and regulative mechanism of p38 signal pathway, we used in vitro binding methods to screen the proteins that interact with p38. Here we report two proteins from mouse macrophage RAW264.7 strain treated with lipopolysaccharide (LPS) or ultraviolet radiation (UV), binding directly to p38. One of them is b-actin identified by peptide mass spectrum and ProFound program. Actin can inhibit the auto-phosphorylation of p38 and the phosphorylation of ATF by p38. It suggests that the binding of actin to p38 in vitro may represent a negative feedback to the kinase activity of p38, which leads to the regulation of p38 pathway and cellular function.

MAPKs represent novel therapeutic targets for gastrointestinal motility disorders

The number of patients suffering from symptoms associated with gastrointestinal(GI) motility disorders is on the rise. GI motility disorders are accompanied by alteration of gastrointestinal smooth muscle functions. Currently available drugs,which can directly affect gastrointestinal smooth muscle and restore altered smooth muscle contractility to normal,are not satisfactory for treating patients with GI motility disorders. We have recently shown that ERK1/2 and p38MAPK signaling pathways play an important role in the contractile response not only of normal intestinal smooth muscle but also of inflamed intestinal smooth muscle. Here we discuss the possibility that ERK1/2 and p38MAPK signaling pathways represent ideal targets for generation of novel therapeutics for patients with GI motility disorders.

Anti-parkinsonian effects of octacosanol in 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-treated mice

Our previous research showed that octacosanol exerted its protective effects in 6-hydroxydopamine-induced Parkinsonian rats. The goal of this study was to investigate whether octacosanol would attenuate neurotoxicity in 1-methyl-4-phenyl-l,2,3,6 tetrahydropyridine （MPTP）-treated C57BL/6N mice and its potential mechanism. Behavioral tests, tyrosine hydroxylase immunohistochemistry and western blot were used to investigate the effects of octacosanol in a mouse model of Parkinson＇s disease. Oral administration of octacosanol （100 mg/kg） significantly improved behavioral impairments Jn mice treated by MPTP and markedly ameliorated morphological appearances of tyrosine hydroxylase-positive neuronal cells in the substantia nigra. Furthermore, octacosanol blocked MPTP-induced phosphorylation of p38MAPK and JNK, but not ERK1/2. These findings implicated that the protective effects afforded by octacosanol might be mediated by blocking the phosphorylation of p38MAPK and JNK on the signa transduction in vivo. Considering its excellent tolerability, octacosanol might be considered as a candidate agent for clinical application in treating Parkinson＇s disease.

Exogenous nerve growth factor protects the hypoglossal nerve against crush injury

Studies have shown that sensory nerve damage can activate the p38 mitogen-activated protein kinase（MAPK）pathway,but whether the same type of nerve injury after exercise activates the p38MAPK pathway remains unclear.Several studies have demonstrated that nerve growth factor may play a role in the repair process after peripheral nerve injury,but there has been little research focusing on the hypoglossal nerve injury and repair.In this study,we designed and established rat models of hypoglossal nerve crush injury and gave intraperitoneal injections of exogenous nerve growth factor to rats for 14 days.p38MAPK activity in the damaged neurons was increased following hypoglossal nerve crush injury;exogenous nerve growth factor inhibited this increase in acitivity and increased the survival rate of motor neurons within the hypoglossal nucleus.Under transmission electron microscopy,we found that the injection of nerve growth factor contributed to the restoration of the morphology of hypoglossal nerve after crush injury.Our experimental findings indicate that exogenous nerve growth factor can protect damaged neurons and promote hypoglossal nerve regeneration following hypoglossal nerve crush injury.

Mechanism of alpha-lipoic acid in attenuating kanamycin-induced ototoxicity

In view of the theory that alpha-lipoic acid effectively prevents cochlear cells from injury caused by various factors such as cisplatin and noise, this study examined whether alpha-lipoic acid can prevent kanamycin-induced ototoxicity. To this end, healthy BALB/c mice were injected subcutaneously with alpha-lipoic acid and kanamycin for 14 days. Auditory brainstem response test showed that increased auditory brainstem response threshold shifts caused by kanamycin were significantly inhibited. Immunohistochemical staining and western blot analysis showed that the expression of phosphorylated p38 mitogen-activated protein kinase and phosphorylated c-Jun N-terminal kinase in mouse cochlea was significantly decreased. The experimental findings suggest that phosphorylated p38 and phosphorylated c-Jun N-terminal kinase mediated kanamycin-induced ototoxic injury in BALB/c mice. AIpha-lipoic acid effectively attenuated kanamycin ototoxicity by inhibiting the kanamycin-induced high expression of phosphorylated p38 and phosphorylated c-Jun N-terminal kinase.

Protective Effects of Sapindus Saponins in Spontaneously Hypertensive Rats

Objectives： To investigate the protective effects of Sapindus saponins in spontaneously hypertensive rats, and the possible cellular and molecular mechanisms. Methods： Thirty-two 16-week-old spontaneously hypertensive rats were randomly divided into four groups （8 in each group）： model group （placebo）, positive control group （27 mg/kg of Captopril Tablets）, Sapindus saponins groups （27 mg/kg and 108 mg/kg, respectively）. Another 8 healthy Wistar-Kyoto strain （WKY） rats were used as the normal group. The animals were treated for 8 weeks. Blood pressure of rats was determined by non-invasive blood pressure meter （BP-6）. Furthermore, the contents of angiotensin Ⅱ （Ang Ⅱ） in plasma and myocardial tissue were determined by enzyme-linked immunosorbent assay （ELISA）, the gene expression of receptor angiotensin type 1 （AT1R） in aorta was determined by quantitative real- time polymerase chain reaction （qRT-PCR）. The protein expression of transforming growth factor- β1 （TGF- 1β1） and AT1R in heart was determined by immunohistochemical staining. The protein expression of p-phosphorylation of p38 mitogen-activated protein kinase （p-p38MAPK） was determined by Western blotting. The contents of interleukin （IL）-1, IL-6 and tumor necrosis factor （TNF） in serum were determined by radioimmunoassay. And the histopathological and morphological changes of aorta and heart tissue samples were assessed semi-quantitatively by hematoxylin-eosin （HE） or Masson staining. Results： Thirty minutes after single or continuous treatment, systolic blood pressure （SBP） was reduced significantly in Sapindus saponins groups. And the contents of Ang 11, IL-1, IL-6 and TNF-α in serum, the expression of AT1R mRNA, p-p38MAPK and TGF- β1 were significantly suppressed dose-dependently （P〈0.05 or 1=〈0.01）. With the Sapindus saponins treatment, compared with those of the model group, the cardiac and aortic pathological changes were ameliorated significantly. Conclusions： Our findings suggest that Sapindus saponins might have protective effects in spontaneously hypertensive rats, the cellular and molecular mechanisms of which might be relevant to the regulation of inflammatory responses mediated by p-p38MAPK signal pathway based on activated Ang Ⅱ and AT1R.

Hydroxychavicol,a polyphenol from Piper betle leaf extract,induces cell cycle arrest and apoptosis in TP53-resistant HT-29 colon cancer cells

This study aims to elucidate the antiproliferative mechanism of hydroxychavicol(HC).Its effects on cell cycle,apoptosis,and the expression of c-Jun N-terminal kinase(JNK)and P38 mitogen-activated protein kinase(MAPK)in HT-29 colon cancer cells were investigated.HC was isolated from Piper betle leaf(PBL)and verified by high-performance liquid chromatography(HPLC),nuclear magnetic resonance(NMR),and gas chromatography-mass spectrometry(GC-MS).The cytotoxic effects of the standard drug 5-fluorouracil(5-FU),PBL water extract,and HC on HT-29 cells were measured after 24,48,and 72 h of treatment.Cell cycle and apoptosis modulation by 5-FU and HC treatments were investigated up to 30 h.Changes in phosphorylated JNK(pJNK)and P38(pP38)MAPK expression were observed up to 18 h.The half maximal inhibitory concentration(IC_(50))values of HC(30μg/mL)and PBL water extract(380μg/mL)were achieved at 24 h,whereas the IC_(50)of 5-FU(50μmol/L)was obtained at 72 h.Cell cycle arrest at the G0/G1 phase in HC-treated cells was observed from12 h onwards.Higher apoptotic cell death in HC-treated cells compared to 5-FU-treated cells(P<0.05)was observed.High expression of pJNK and pP38 MAPK was observed at 12 h in HC-treated cells,but not in 5-FU-treated HT-29 cells(P<0.05).It is concluded that HC induces cell cycle arrest and apoptosis of HT-29 cells,with these actions possibly mediated by JNK and P38 MAPK.