ER Stress-Mediated Cell Damage Contributes to the Release of EDA~＋ Fibronectin from Hepatocytes in Nonalcoholic Fatty Liver Disease

Fibronectin containing extra domain A（EDA~＋ FN）,a functional glycoprotein participating in several cellular processes,correlates with chronic liver disease.Herein,we aim to investigate the expression and secretion of EDA~＋ FN from hepatocytes in nonalcoholic fatty liver disease（NAFLD） and the underlying mechanisms.Circulating levels of EDA~＋ FN were determined by ELISA in clinical samples.Western blotting and flow cytometry were performed on L02 and Hep G2 cell lines to analyze whether the levels of EDA~＋ FN were associated with endoplasmic reticulum（ER） stress-related cell death.Circulating levels of EDA~＋ FN in NAFLD patients were significantly higher than those in control subjects,and positively related with severity of ultrasonographic steatosis score.In cultured hepatocytes,palmitate up-regulated the expression of EDA~＋ FN in a dose-dependent manner.Conversely,when the cells were pretreated with 4-phenylbutyrate,a specific inhibitor of ER stress,up-regulation of EDA~＋ FN could be abrogated.Moreover,silencing CHOP by sh RNA enhanced the release of EDA~＋ FN from hepatocytes following palmitate treatment,which was involved in ER stress-related cell damage.These findings suggest that the up-regulated level of EDA~＋ FN is associated with liver damage in NAFLD,and ER stress-mediated cell damage contributes to the release of EDA~＋ FN from hepatocytes.

Potential therapeutic interventions based on the role of the endoplasmic reticulum stress response in progressive neurodegenerative diseases

In 1945,Porter et al.published an electon microscopy study of cultured chick fibroblasts in which they observed：＇a granular background and details of a darker lacelike reticulum which in places appears to be made up of chains of＂vesicles＂＇（Porter et al.,1945）.This constituted the first published observation of the endoplasmic reticulum（ER）and,while it was not evident at that time,this cytoplasmic system of interconnecting membrane-lined channels, comprising vesicles, tubules and cisternae, has numerous important functions.

Beneficial mechanisms of aerobic exercise on hepatic lipid metabolism in non-alcoholic fatty liver disease

BACKGROUND：Non-alcoholic fatty liver disease（NAFLD）refers to any fatty liver disease that is not due to excessive use of alcohol.NAFLD probably results from abnormal hepatic lipid metabolism and insulin resistance.Aerobic exercise is shown to improve NAFLD.This review aimed to evaluate the molecular mechanisms involved in the beneficial effects of aerobic exercise on NAFLD.DATA SOURCE：We searched articles in English on the role of aerobic exercise in NAFLD therapy in Pub Med.RESULTS： The mechanisms of chronic aerobic exercise in regulating the outcome of NAFLD include： （i） reducing in- trahepatic fat content by down-regulating sterol regulatory element-binding protein-lc and up-regulating peroxisome proliferator-activated receptor y expression levels; （ii） decreas- ing hepatic oxidative stress through modulating the reactive oxygen species, and enhancing antioxidant enzymes such as catalase and glutathione peroxidase; （iii） ameliorating hepatic inflammation via the inhibition of pro-inflammatory media- tors such as tumor necrosis factor-alpha and interleukin-1 beta; （iv） attenuating mitochondrial dependent apoptosis by reducing cytochrome C released from the mitochondria to the cytosol; and （v） inducing hepato-protective autophagy. CONCLUSION： Aerobic exercise, via different mechanisms, significantly decreases the fat content of the liver and improves the outcomes of patients with NAFLD.

Adenyl cyclase activator forskolin protects against Huntington's disease-like neurodegenerative disorders

Long term suppression of succinate dehydrogenase by selective inhibitor 3-nitropropionic acid has been used in rodents to model Huntington＇s disease where mitochondrial dysfunction and oxidative damages are primary pathological hallmarks for neuronal damage. Improvements in learning and memory abilities, recovery of energy levels, and reduction of excitotoxicity damage can be achieved through activation of Adenyl cyclase enzyme by a specific phytochemical forskolin. In this study, intraperitoneal administration of 10 mg/kg 3-nitropropionic acid for 15 days in rats notably reduced body weight, worsened motor cocordination（grip strength, beam crossing task, locomotor activity）, resulted in learning and memory deficits, greatly increased acetylcholinesterase, lactate dehydrogenase, nitrite, and malondialdehyde levels, obviously decreased adenosine triphosphate, succinate dehydrogenase, superoxide dismutase, catalase, and reduced glutathione levels in the striatum, cortex and hippocampus. Intragastric administration of forskolin at 10, 20, 30 mg/kg dose-dependently reversed these behavioral, biochemical and pathological changes caused by 3-nitropropionic acid. These results suggest that forskolin exhibits neuroprotective effects on 3-nitropropionic acid-induced Huntington＇s disease-like neurodegeneration.

Neuroprotective Effect of Peptides Extracted from Walnut(Juglans Sigilata Dode) Proteins on Aβ25-35-induced Memory Impairment in Mice

Alzheimer＇s disease（AD） is one of the major neurodegenerative disorders of the elderly, which is characterized by the accumulation and deposition of amyloid-beta（Aβ） peptide in human brains. Oxidative stress and neuroinflammation induced by Aβ in brain are increasingly considered to be responsible for the pathogenesis of AD. The present study aimed to determine the protective effects of walnut peptides against the neurotoxicity induced by Aβ25-35 in vivo. Briefly, the AD model was induced by injecting Aβ25-35 into bilateral hippocampi of mice. The animals were treated with distilled water or walnut peptides（200, 400 and 800 mg/kg, p.o.） for five consecutive weeks. Spatial learning and memory abilities of mice were investigated by Morris water maze test and step-down avoidance test. To further explore the underlying mechanisms of the neuroprotectivity of walnut peptides, the activities of superoxide dismutase（SOD）, glutathione（GSH）, acetylcholine esterase（ACh E）, and the content of malondialdehyde（MDA） as well as the level of nitric oxide（NO） in the hippocampus of mice were measured by spectrophotometric method. In addition, the levels of 8-hydroxy-2＇-deoxyguanosine（8-OHd G）, tumor necrosis factor-α（TNF-α）, interleukin 1β（IL-1β） and IL-6 in the samples were determined using ELISA. The hippocampal expressions of inducible nitric oxide synthase（i NOS） and nuclear factor κB（NF-κB） were evaluated by Western blot analysis. The results showed that walnut peptides supplementation effectively ameliorated the cognitive deficits and memory impairment of mice. Meanwhile, our study also revealed effective restoration of levels of antioxidant enzymes as well as inflammatory mediators with supplementation of walnut peptides（400 or 800 mg/kg）. All the above findings suggested that walnut peptides may have a protective effect on AD by reducing inflammatory responses and modulating antioxidant system.

Silencing the gene encoding C/EBP homologous protein lessens acute brain injury following ischemia/reperfusion

C/EBP homologous protein, an important transcription factor during endoplasmic reticulum stress, participates in cell apoptosis mediated by endoplasmic reticulum stress. Previous studies have shown that C/EBP homologous protein mediates nerve injury during Alzheimer＇s disease, subarachnoid hemorrhage and spinal cord trauma. In this study, we introduced C/EBP homologous protein short hairpin RNA into the brains of ischemia/reperfusion rat models via injection of lentiviral vector through the left lateral ventricle. Silencing C/EBP homologous protein gene expression significantly reduced cerebral infarction volume, decreased water content and tumor necrosis factor-α and interleukin-1β mRNA expression in brain tissues following infarction, diminished the number of TUNEL-positive cells in the infarct region, decreased caspase-3 protein content and increased Bcl-2 protein content. These results suggest that silencing C/EBP homologous protein lessens cell apoptosis and inflammatory reactions, thereby protecting nerves.

An analysis of factors in fluencing electrocardiogram stress test for detecting coronary heart disease

Objective To evaluate factors influencing electrocardiogram (ECG) stres s test Methods The treadmill stress test and coronary angiogram (CAG) records were reviewed retrospectively in 435 consecutive patients with chest pain betwee n 1991 and 1997 There were 44 cases with normal CAG but positive exercise stre s s test results (falsepositive, Group A), and 33 cases with both negative CAG a nd negative exercise test (truenegative, Group B) The baseline ECG, echocard i ogram, abnormal systolic blood pressure response and history of diabetes mellit us and hypertension in the two groups were compared Results There was no significant difference between the two groups with r espect to age, gender, and antianginal medication More patients in Group A had hype rtension (523% vs 273%, P <005) and diabetes mellitus (15 9% v s 0%, P <005) Left ventricular (LV) hypertrophy in baseline E C G and by echocardiogram was more often present in Group A (250% vs 30%, P <005; 364% vs 121%, P <005) There were no signi fican t differences between the two groups with respect to maximal heart rate, maxima l s ystolic blood pressure (BP), metabolic equivalents, postexercise systolic BP, te rmination for exercise test, baseline ECG with bundle branch block and ST depres sion Conclusion Our results suggest that LV hypertrophy and a history of hyp ertension or diabetes mellitus are the main factors influencing ECG stress test for detecting coronary heart disease

Naringin ameliorates acetic acid induced colitis through modulation of endogenous oxido-nitrosative balance and DNA damage in rats

The aim of this study was to evaluate the effect of naringin on experimentally induced inflammatory bowel dis- ease in rats. Naringin （20, 40 and 80 mg/kg） was given orally for 7 days to Wistar rats before induction of colitis by intrarectal instillation of 2 mL of 4% （v/v） acetic acid solution. The degree of colonic mucosal damage was analyzed by examining mucosal damage, ulcer area, ulcer index and stool consistency. Intrarectal administration of 4% acetic acid resulted in significant modulation of serum alkaline phosphatase, lactate dehydrogenase, superoxide dismutase （SOD）, glutathione （GSH）, malondialdehyde （MDA） and myeloperoxidase （MPO） content along with colonic nitric oxide （NO）, xanthine oxidase （XO） level and protein carbonyl content in the colonic tissue as well as in blood. Naringin （40 and 80 mg/kg） exerted a dose dependent （P 〈 0.05） ameliorative effect, as it significantly increased hematological parameter as well as colonic SOD and GSH. There was a significant （P 〈 0.05） and dose dependant inhibition of macroscopical score, ulcer area along with colonic MDA, MPO activity by the 7 days of pretreatment of naringin （40 and 80 mg/kg）. Biochemical studies revealed a significant （P 〈 0.05） dose dependant inhibition in serum alkaline phosphatase （ALP） and lactate dehydrogenase （LDH） levels by pretreatment of naringin. Increased levels of colonic NO, XO, protein carbonyl content and DNA damage were also sig- nificantly decreased by naringin pretreatment. The findings of the present investigation propose that naringin has an anti-inflammatory, anti-oxidant and anti-apoptotic potential effect at colorectal sites as it modulates the production and expression of oxidative mediators such as MDA, MPO, NO and XO, thus reducing DNA damage.

Salidroside Protects Against 6-Hydroxydopamine-Induced Cytotoxicity by Attenuating ER Stress

Parkinson＇s disease （PD） is a neurodegenera- tive disease characterized by a persistent decline of dopaminergic （DA） neurons in the substantia nigra pars compacta. Despite its frequency, effective therapeutic strategies that halt the neurodegenerative processes are lacking, reinforcing the need to better understand the molecular drivers of this disease. Importantly, increasing evidence suggests that the endoplasmic reticulum （ER） stress-induced unfolded protein response is likely involved in DA neuronal death. Salidroside, a major compound isolated from Rhodiola rosea L., possesses potent anti- oxidative stress properties and protects against DA neu- ronal death. However, the underlying mechanisms are not well understood. In the present study, we demonstrate that salidroside prevents 6-hydroxydopamine （6-OHDA）- induced cytotoxicity by attenuating ER stress. Further- more, treatment of a DA neuronal cell line （SN4741） and primary cortical neurons with salidroside significantly reduced neurotoxin-induced increases in cytoplasmic reactive oxygen species and calcium, both of which cause ER stress, and cleaved caspase-12, which is responsible for ER stress-induced cell death. Together, these results sug- gest that salidroside protects SN4741 cells and primary cortical neurons from 6-OHDA-induced neurotoxicity by attenuating ER stress. This provides a rationale for the investigation of salidroside as a potential therapeutic agent in animal models of PD.

Effects of Berberine on Hepatic Sirtuin 1-uncoupling Protein 2 Pathway in Non-alcoholic Fatty Liver Disease Rats Induced by High-fat Diet

Objective To investigate the involvement of sirtuin 1（SIRT1）-uncoupling protein 2（UCP2） pathway in the development of non-alcoholic fatty liver disease and whether berberine exerts its effects by regulating this pathway. Methods Male SD rats were divided into three groups： normal control group, high-fat diet group, and berberine supplement group. The rats in the normal control group were given normal diet while the rats in the other two groups were fed with high-fat diet. Rats in the berberine supplement group were concurrently given berberine（100 mg/kg body weight） once daily. After 16 weeks, the levels of serum, liver lipids, and serum aminotransferase were measured using an automatic biochemical analyzer. Superoxide dismutase（SOD） activity and malondialdehyde（MDA） content in the liver were measured using commercial kits. Histopathological changes of liver tissues were observed by hematoxylin and eosin（HE） staining and Oil Red O staining. The hepatic m RNA and protein levels of SIRT1 and UCP2 were assayed by reverse transcription polymerase chain reaction（RT-PCR） or Western blotting. Results Berberine supplement could significantly decrease the serum and liver lipid contents in rats fed with high-fat diet. Meanwhile, SOD level was significantly elevated, but MDA level was reduced in the liver. The results of HE and Oil Red O staining showed that the hepatic steatosis was alleviated in berberine supplement group. Furthermore, berberine induced an increase in SIRT1 expression but a decrease in UCP2 expression. Conclusion The regulation of hepatic SIRT1-UCP2 pathway may be an important mechanism by which berberine exerts the beneficial effects in NAFLD rats.