Buyang Huanwu Decoction promotes neurogenesis via sirtuin 1/autophagy pathway in a cerebral ischemia model.
ABSTRACT: Stroke is one of the main causes of disease‑related mortality worldwide. Buyang Huanwu Decoction (BHD) has been used to protect against stroke and stroke‑induced disability for several years in China. Studies have shown that BHD can relieve neuronal damage in rats with cerebral ischemia/reperfusion (I/R) injury. However, the mechanism remains unclear. A middle cerebral artery occlusion and reperfusion (MCAO‑R) model was used in the present study. The animals were treated with BHD (5, 10 and 20 g/kg) or rapamycin. Infarct size and modified neurological severity score were calculated on day 5 following MCAO‑R surgery. Cellular changes around the ischemic penumbra were revealed by hematoxylin and eosin and Nissl staining. The protein expression levels of nestin, brain‑derived neurotrophic factor (BDNF), doublecortin on the X chromosome (DCX) and autophagy‑related proteins (beclin 1, LC3‑II and p62) in the peri‑ischemic area of the brain were detected. The results demonstrated that post‑surgical treatment with BHD reduced the brain infarct size and improved neurological deficits in MCAO‑R rats. BHD protected against MCAO‑R‑induced neuronal impairment and promoted neurogenesis, increased the protein expression of nestin, BDNF and DCX and markedly enhanced autophagy by increasing beclin 1 and LC3‑II and decreasing p62. Meanwhile, BHD promoted the expression of sirtuin 1 (SIRT1), an important regulator of autophagy. In conclusion, the present study suggested that post‑surgical treatment with BHD could protect rat brains from I/R injury, potentially through the SIRT1/autophagy pathway.
Project description:Ganglioside GM1, which is particularly abundant in the central nervous system (CNS), is closely associated with the protection against several CNS disorders. However, controversial findings have been reported on the role of GM1 following ischemic stroke. In the present study, using a rat middle cerebral artery occlusion (MCAO) model, we investigated whether GM1 can protect against ischemic brain injury and whether it targets the autophagy pathway. GM1 was delivered to Sprague-Dawley male rats at 3 doses (25 mg/kg, 50 mg/kg, 100 mg/kg) by intraperitoneal injection soon after reperfusion and then once daily for 2 days. The same volume of saline was given as a control. Tat-Beclin-1, a specific autophagy inducer, was administered by intraperitoneal injection at 24 and 48 hours post-MCAO. Infarction volume, mortality and neurological function were assessed at 72 hours after ischemic insult. Immunofluorescence and Western blotting were performed to determine the expression of autophagy-related proteins P62, LC3 and Beclin-1 in the penumbra area. No significant changes in mortality and physiological variables (heart rate, blood glucose levels and arterial blood gases) were observed between the different groups. However, MCAO resulted in enhanced conversion of LC3-I into LC3-II, P62 degradation, high levels of Beclin-1, a large area infarction (26.3±3.6%) and serious neurobehavioral deficits. GM1 (50 mg/kg) treatment significantly reduced the autophagy activation, neurobehavioral dysfunctions, and infarction volume (from 26.3% to 19.5%) without causing significant adverse side effects. However, this biological function could be abolished by Tat-Beclin-1.GM1 demonstrated safe and robust neuroprotective effects that are associated with the inhibition of autophagy following experimental stroke.
Project description:<b>Background:</b> Electroacupuncture (EA) treatment in ischemic stroke has been highlighted recently; however, the specific mechanism is still elusive. Autophagy is considered a new target for cerebral ischemia/reperfusion (I/R), but whether it plays a role of protecting or causing rapid cell apoptosis remains unclear. Studies have reported that the reduction in lysine 16 of histone H4 acetylation coheres with autophagy induction. The primary purpose of the study was to explore whether EA could alleviate I/R via autophagy-mediated histone H4 lysine 16 acetylation in the middle cerebral artery occlusion (MCAO) rat model. <b>Methods:</b> One hundred and twenty male Sprague-Dawley rats were divided into five groups: control group, MCAO group, MCAO+EA group, MCAO+EA+hMOF siRNA group, and MCAO+EA+Sirt1 inhibitor group. EA was applied to "Baihui" (Du20) and "Renzhong" (Du26) at 5 min after modeling and 16 h after the first EA intervention. The structure and molecular markers of the rat brain were evaluated. <b>Results:</b> EA significantly alleviated I/R injury by upregulating the expressions of Sirt1, Beclin1, and LC3-II and downregulating the expressions of hMOF and H4K16ac. In contrast, the Sirt1 inhibitor lowered the increase in Sirt1, Beclin1, and LC3-II and enhanced the level of hMOF and H4K16ac expressions associated with EA treatment. Besides, ChIP assay revealed that the binding of H4K16ac in the Beclin1 promoter region of the autophagy target gene was significantly raised in the MCAO+EA group and MCAO+EA+hMOF siRNA group. <b>Conclusions:</b> EA treatment inhibited the H4K16ac process, facilitated autophagy, and alleviated I/R injury. These findings suggested that regulating histone H4 lysine 16 acetylation-mediated autophagy may be a key mechanism of EA at Du20 and Du26 to treat I/R.
Project description:Renal ischemia/reperfusion (I/R) injury often occurs during multiple organ failure and sepsis, and autophagy may serve a role in I/R injury. The aim of the present study was to explore the effect of microRNA (miR)‑30a‑5p on autophagy in renal I/R injury. miR‑30a‑5p and autophagy‑related protein expression levels in renal I/R injury mouse models and in hypoxia/re‑oxygenation HK‑2 cell models were determined using reverse transcription‑quantitative PCR or western blotting; apoptosis was analyzed using flow cytometry. The effects of miR‑30a‑5p, Beclin‑1 and autophagy‑related gene 16 (ATG16) on the proliferation and autophagy of HK‑2 cells were analyzed through gain‑ and loss‑of‑function studies. miR‑30a‑5p expression was significantly decreased after renal I/R injury in the <i>in vivo</i> and <i>in vitro</i> experiments. Renal I/R injury led to upregulated expression of autophagy‑related proteins microtubule‑associated protein light chain 3 (LC3)‑Ⅱ and Beclin‑1, and downregulated expression of p62. miR‑30a‑5p overexpression decreased the number of LC3 punctae, decreased HK‑2 cell apoptosis, increased p62 expression and decreased LC3‑Ⅱ and Beclin‑1 expression. Inhibition of miR‑30a‑5p exhibited the opposite effects. A luciferase reporter assay demonstrated that miR‑30a‑5p targeted Beclin‑1. Beclin‑1 overexpression led to a significant increase in LC3‑Ⅱ expression and a decrease in p62 expression, as well as a significant increase in apoptosis. Beclin‑1 overexpression also increased the protein expression level of ATG16. Downregulation of Beclin‑1 decreased the expression of LC3‑Ⅱ, elevated the p62 level and decreased apoptosis. ATG16 knockdown showed similar effects as those of Beclin‑1 downregulation. In conclusion, miR‑30a‑5p was increased in renal I/R injury and might mitigate autophagy by regulating the Beclin‑1/ATG16 pathway.
Project description:The main purpose of the study was to investigate the antiapoptotic effect of electroacupuncture (EA) in the acute stage of ischaemic stroke in rats. The cerebral ischemia model was established by middle cerebral artery occlusion (MCAO)/reperfusion in rats. A single EA treatment was performed at the acute stage of ischaemic stroke. The neurological function, brain water content, apoptotic cell number, and cerebral infarct volume were assessed in stroke rats. The expression of autophagy-related proteins (LC3II/I, Beclin1, P62, and LAMP1), Sirtuin 1 (SIRT1), p-JNK, p-ERK1/2, and cleaved caspase-3 (CCAS3) were measured by Western blot, immunofluorescence, and immunohistochemistry. Rapamycin (RAP, an activator of autophagy) was used to confirm the antiapoptotic effect of EA <i>via</i> regulating autophagy. The brain edema infarct size and apoptotic cell number were increasing within 3 days following stroke, and brain edema reached its peak at 24 h after stroke. EA treatment at 24 h after ischaemic stroke obviously suppressed the number of apoptotic cells and brain edema. However, there were no significant differences in infarct volumes among EA-12 h, EA-24 h, and MCAO/R group. Moreover, EA treatment at 24 h after ischaemic stroke obviously suppressed the expression of CCAS3, LC3II/I, Beclin1 while increasing the level of P62 and LAMP1 and hence mediating autophagy, which was reversed by RAP. Meanwhile, the expression of SIRT1, p-ERK1/2, p-JNK were promoted by EA at 24 h after ischaemic stroke. In conclusion, EA treatment may suppress apoptosis possibly <i>via</i> regulating autophagy in the acute period after ischaemic stroke, hence reducing brain injury.
Project description:<h4>Background</h4>Ischemic postconditioning (IPOC), or relief of ischemia in a stuttered manner, has emerged as an innovative treatment strategy to reduce programmed cell death, attenuate ischemic injuries, and improve neurological outcomes. However, the mechanisms involved have not been completely elucidated. Recent studies indicate that autophagy is a type of programmed cell death that plays elusive roles in controlling neuronal damage and metabolic homeostasis. This study aims to determine the role of autophagy in IPOC-induced neuroprotection against focal cerebral ischemia in rats.<h4>Methodology/principal findings</h4>A focal cerebral ischemic model with permanent middle cerebral artery (MCA) occlusion plus transient common carotid artery (CCA) occlusion was established. The autophagosomes and the expressions of LC3/Beclin 1/p62 were evaluated for their contribution to the activation of autophagy. We found that autophagy was markedly induced with the upregulation of LC3/Beclin 1 and downregulation of p62 in the penumbra at various time intervals following ischemia. IPOC, performed at the onset of reperfusion, reduced infarct size, mitigated brain edema, inhibited the induction of LC3/Beclin 1 and reversed the reduction of p62 simultaneously. Rapamycin, an inducer of autophagy, partially reversed all the aforementioned effects induced by IPOC. Conversely, autophagy inhibitor 3-methyladenine (3-MA) attenuated the ischemic insults, inhibited the activation of autophagy, and elevated the expression of anti-apoptotic protein Bcl-2, to an extent comparable to IPOC.<h4>Conclusions/significance</h4>The present study suggests that inhibition of the autophagic pathway plays a key role in IPOC-induced neuroprotection against focal cerebral ischemia. Thus, pharmacological inhibition of autophagy may provide a novel therapeutic strategy for the treatment of stroke.
Project description:SIRT1 could protect degenerative human NP cells against apoptosis, and there were extensive and intimate connection between apoptosis and autophagy. Up to now, the role of autophagy in the process of human IVD degeneration is unclear. We sought to explore the relationship between autophagy and human IVD degeneration and to understand whether autophagy is involved in the protective effect of SIRT1 against apoptosis in NP cells. Our results showed that the autophagosomes number, the mRNA level of LC3 and Beclin-1, the protein expression of LC3-II/I and Beclin-1, decreased in NP from DDD. Resveratrol could increase the protein expression of LC3-II/I and Beclin-1, and reduce apoptosis in degenerative NP cells. In contrast, the protein levels of LC3-II/I and Beclin-1 were down-regulated and apoptosis level was significantly up-regulated in treatment with nicotinamide or SIRT1-siRNA transfection. Further analysis identified that the expression of cleaved Caspase3 and apoptosis incidence significantly increased with the pretreatment of bafilomycin A, whether resveratrol was added or not. These suggested that autophagy may play an important role in IVD degeneration, and SIRT1 protected degenerative human NP cells against apoptosis via promoting autophagy. These findings would aid in the development of novel therapeutic approaches for degenerative disc disease treatment.
Project description:The purpose of this study was to ascertain the relative contribution of neural stem/progenitor cells (NSPCs) of the subventricular zone (SVZ) to lineages that repopulate the injured striatum following focal ischemia. We utilized a tamoxifen-inducible Cre/loxP system under control of the nestin promoter, which provides permanent YFP labeling of multipotent nestin(+) SVZ-NSPCs prior to ischemic injury and continued YFP expression in all subsequent progeny following stroke. YFP reporter expression was induced in adult male nestin-CreER(T2):R26R-YFP mice by tamoxifen administration (180 mg kg(-1), daily for 5 days). Fourteen days later, mice were subjected to 60-min transient middle cerebral artery occlusion (MCAO) and sacrificed at 2 days, 2 weeks, or 6 weeks post-MCAO for phenotypic fate mapping of YFP(+) cells using lineage-specific markers. Migration of YFP(+) cells from SVZ into the injured striatal parenchyma was apparent at 2 and 6 weeks, but not 2 days, post-MCAO. At 2 weeks post-MCAO, the average percent distribution of YFP(+) cells within the injured striatal parenchyma was as follows: 10% Dcx(+) neuroblasts, 15-20% oligodendrocyte progenitors, 59% GFAP(+) astrocytes, and only rare NeuN(+) postmitotic neurons. A similar phenotypic distribution was observed at 6 weeks, except for an increased average percentage of YFP(+) cells that expressed Dcx(+) (20%) or NeuN (5%). YFP(+) cells did not express endothelial markers, but displayed unique anatomical relationships with striatal vasculature. These results indicate that nestin(+) NSPCs within the SVZ mount a multilineage response to stroke that includes a gliogenic component more predominant than previously appreciated.
Project description:<h4>Background</h4>We previously, reported that granulocyte-colony stimulating factor (G-CSF) reduces cardiomyocyte apoptosis in diabetic cardiomyopathy. However, the underlying mechanisms are not yet fully understood. Therefore, we investigated whether the mechanisms underlying of the anti-apoptotic effects of G-CSF were associated with autophagy using a rat model of diabetic cardiomyopathy.<h4>Methods</h4>Diabetic cardiomyopathy was induced in rats through a high-fat diet combined with low-dose streptozotocin and the rats were then treated with G-CSF for 5 days. Rat H9c2 cardiac cells were cultured under high glucose conditions as an in vitro model of diabetic cardiomyopathy. The extent of apoptosis and protein levels related to autophagy (Beclin-1, microtubule-binding protein light chain 3 [LC3]-II/LC3-I ratio, and P62) were determined for both models. Autophagy determination was performed using an Autophagy Detection kit.<h4>Results</h4>G-CSF significantly reduced cardiomyocyte apoptosis in the diabetic myocardium in vivo and led to an increase in Beclin-1 level and the LC3-II/LC3-I ratio, and decreased P62 level. Similarly, G-CSF suppressed apoptosis, increased Beclin-1 level and LC3-II/LC3-I ratio, and decreased P62 level in high glucose-induced H9c2 cardiac cells in vitro. These effects of G-CSF were abrogated by 3-methyladenine, an autophagy inhibitor. In addition, G-CSF significantly increased autophagic flux in vitro.<h4>Conclusion</h4>Our results suggest that the anti-apoptotic effect of G-CSF might be significantly associated with the up-regulation of autophagy in diabetic cardiomyopathy.
Project description:<h4>Background</h4>Current evidence suggests a central role for autophagy in many neurodegenerative diseases including Alzheimer's disease, Huntington's disease, Parkinson's disease and amyotrophic lateral sclerosis. Furthermore, it is well admitted that inflammation contributes to the progression of these diseases. Interestingly, crosstalks between autophagy and inflammation have been reported in vitro and at the peripheral level such as in Crohn's disease. However, the impact of systemic inflammation on autophagic components in the brain remains to be documented. Therefore, this study monitored autophagy markers after acute and chronic lipopolysaccharide (LPS)-induced inflammatory stress in mice.<h4>Results</h4>We showed that acute inflammation, 24 h post-intraperitoneal 10 mg/kg LPS, substantially increased cytokine production (Interleukin(IL)-1β, Tumor necrosis factor (TNF)-α and IL-6), decreased the levels of autophagy markers (Beclin-1, p62 and LC3 II) and reduced p70S6K activation in cortex and hippocampus. In hippocampus, IL-1β levels and LC3 II expression were positively and highly correlated and a negative correlation was noted between TNF-α levels and p70S6K activation. Chronic inflammation by injection of 0.5 mg/kg LPS every three days during three months led to a moderate IL-1β production and decreased TNF-α levels. Interestingly, Beclin-1 and LC3 II levels decreased while those of p62 increased. Cortical IL-1β levels positively correlated with Beclin-1 and LC3 II and on the contrary inversely correlated with p62.<h4>Conclusion</h4>The present study is the first showing links between IL-1β-mediated inflammation and autophagy in the brain. It could open to new therapeutic strategies in brain diseases where regulation impairment of inflammation and autophagy progress with the severity of diseases.
Project description:Hyperammonemia and sarcopenia (loss of skeletal muscle) are consistent abnormalities in cirrhosis and portosystemic shunting. We have shown that muscle ubiquitin-proteasome components are not increased with hyperammonemia despite sarcopenia. This suggests that an alternative mechanism of proteolysis contributes to sarcopenia in cirrhosis. We hypothesized that autophagy could be this alternative pathway since we observed increases in classic autophagy markers, increased LC3 lipidation, beclin-1 expression, and p62 degradation in immunoblots of skeletal muscle protein in cirrhotic patients. We observed similar changes in these autophagy markers in the portacaval anastamosis (PCA) rat model. To determine the mechanistic relationship between hyperammonemia and autophagy, we exposed murine C(2)C(12) myotubes to ammonium acetate. Significant increases in LC3 lipidation, beclin-1 expression, and p62 degradation occurred by 1 h, whereas autophagy gene expression (LC3, Atg5, Atg7, beclin-1) increased at 24 h. C(2)C(12) cells stably expressing GFP-LC3 or GFP-mCherry-LC3 constructs showed increased formation of mature autophagosomes supported by electron microscopic studies. Hyperammonemia also increased autophagic flux in mice, as quantified by an in vivo autophagometer. Because hyperammonemia induces nitration of proteins in astrocytes, we quantified global muscle protein nitration in cirrhotic patients, in the PCA rat, and in C(2)C(12) cells treated with ammonium acetate. Increased protein nitration was observed in all of these systems. Furthermore, colocalization of nitrated proteins with GFP-LC3-positive puncta in hyperammonemic C(2)C(12) cells suggested that autophagy is involved in degradation of nitrated proteins. These observations show that increased skeletal muscle autophagy in cirrhosis is mediated by hyperammonemia and may contribute to sarcopenia of cirrhosis.