Gender-related difference in altered fractional amplitude of low-frequency fluctuations after electroacupuncture on primary insomnia patients: A resting-state fMRI study.

BACKGROUND: Primary insomnia (PI) is defined as a sleep disorder with no definite cause or inducement. Electroacupuncture, a treatment of inserting needles into specific points on the body surface and applying electrical stimulation, has been proved effective in treating PI with minimal adverse effects. However, the influence of gender difference on the clinical treatment efficacy of electroacupuncture for PI patients remains unclear. Therefore, we designed a clinical trial to compare the clinical treatment efficacy of electroacupuncture for PI patients with different genders. The research on the mechanism of electroacupuncture suggested it could modulate the sleep and wakefulness by activating or deactivating brain regions via a needling/tactile somatosensory specific stimulus. Therefore, we also designed a resting-state functional magnetic resonance imaging (rs-fMRI) study to detect the spontaneous brain activity of PI patients before and after the electroacupuncture treatment. METHOD: Thirty PI patients were recruited to accept 5-week electroacupuncture treatment on HT-7. Athens Insomnia Scale (AIS) and Pittsburgh sleep quality index (PSQI) questionnaires were used to evaluate the clinical treatment efficacy. Rs-fMRI was employed to observe the spontaneous brain activity in the resting state at the baseline and after 5 weeks of electroacupuncture treatment, which was measured by the fractional amplitude of low-frequency fluctuations (fALFF). RESULT: The AIS and PSQI scores were significantly decreased both in the female PI group and the male PI group after treatment. The decreased PSQI of female patients was significantly more than that of male patients (p < .05). The gender-related difference in the cerebral response to electroacupuncture was mainly in posterior cingulate and supramarginal gyrus. CONCLUSION: There is a gender-related difference in the clinical treatment efficacy of electroacupuncture for PI patients, and female patients may benefit more from electroacupuncture. Gender-related differences in the cerebral response to electroacupuncture may be one of the factors affecting clinical treatment efficacy.

Effectiveness and cerebral responses of multi-points acupuncture for primary insomnia: a preliminary randomized clinical trial and fMRI study.

BACKGROUND: Primary insomnia (PI) is characterized by difficulties in initiating sleep or maintaining sleep, which lead to many serious diseases. Acupuncture for PI has drawn attention with its effectiveness and safety. However, the operation of choosing acupoints lacks scientific suggestion. Our trial aims to provide reference and scientific basis for the selection of acupoints and to explore its possible mechanism. METHODS: A patient-assessor-blinded, randomized and sham controlled trial was designed to compare the efficacy of 5-weeks acupuncture at a single acupoint, the combination of multi-acupoints, and a sham point. The Pittsburgh sleep quality index and Athens Insomnia Scale questionnaire were used for the primary clinical outcomes, while polysomnography was performed for the secondary clinical outcomes. The resting state functional MRI was employed to detect the cerebral responses to acupuncture. The brain activity in resting state was measured by calculating the fractional amplitude of low-frequency fluctuations (fALFF), which reflected the idiopathic activity level of neurons in the resting state. These results were analyzed by two factorial ANOVA test and post-hoc t-tests. RESULTS: The clinical outcomes suggest that acupuncture could improve clinical symptoms, and the combination of multi-acupoints might lead to a better clinical efficacy. The rs-fMRI results suggested that the brain activity of certain regions was related to the sleep experience, and acupuncture could regulate the activity of these regions. Furthermore, the combination of multi-acupoints could impact more regions which were influenced by the sleep experience. CONCLUSIONS: Acupuncture has been proven to be beneficial for PI patients, and the combination of multi-acupoints might improve its efficacy. TRIAL REGISTRATION: This trial has been registered on the U.S. National Library of Medicine (https://clinicaltrials.gov) ClinicalTrials.gov Identifier: NCT02448602 . Registered date: 14/04/2015.

Meta-analysis of 5-hydroxytryptamine transporter gene promoter region polymorphism and post-stroke depression.

OBJECTIVE: To investigate the relationship between 5-hydroxytryptamine transporter gene promoter region (5-HTTLPR) gene polymorphism and post-stroke depression (PSD). METHODS: We searched the CNKI, China Science and Technology Journal, China WanFang, PubMed, Embase, and Web of Science databases for studies of the relationship between 5-HTTLPR polymorphism and PSD. Data were evaluated using Stata software. RESULTS: The L allele was significantly related to the S allele (OR = 0.57, 95% confidence interval (CI) 0.49-0.65). The dominant genotype LL + LS was related to SS (OR = 0.48, 95%CI 0.39-0.59), the recessive genotype LL was related to LS + SS (OR = 0.39, 95%CI: 0.30-0.51), the homozygous genotype LL was related to SS (OR = 0.24, 95%CI 0.18-0.33), and the heterozygous genotype LS was related to SS (OR = 0.55, 95 CI 0.44-0.68). All the differences were significant. Ethnicity subgroup analysis showed significant differences among the five genotypes in both Asians and Caucasians. Hardy-Weinberg equilibrium (HWE) subgroup analysis showed that, after removal of a non-HWE-conforming control group, all five genotypes were significant and genotypes LL, LS + LL, and LS and L allele had beneficial effects on recovery from PSD. CONCLUSION: 5-HTTLPR gene polymorphism is strongly associated with PSD, and the LL, LS + LL, and LS genotypes and L allele may protect against this condition.

Evaluation of the age-related and gender-related differences in patients with primary insomnia by fractional amplitude of low-frequency fluctuation: A resting-state functional magnetic resonance imaging study.

Insomnia patients with different gender and age usually had different sleep experience. Primary insomnia (PI) has been considered to be a disorder of hyper-arousal in the physiologic, emotional, or cognitive network. Although the hyper-arousal brain regions can be shown by comparing the brain activity of PI patients with normal people at rest, whether the brain activity of PI patients varied according to age and gender and whether age and gender could affect the distribution of hyper-arousal brain regions are still worthy of further exploration. Hence, a resting state functional magnetic resonance imaging study (No. NCT02448602) was designed to observe the brain activity of thirty PI patients and 15 healthy controls (HCs). The brain activity in resting state was measured by calculating the fractional amplitude of low-frequency fluctuations (fALFF), which reflected the idiopathic activity level of neurons. Multiple regression was performed to investigate the age and gender-related differences of brain activity in PI patients (P < .001, Family Wise Error (FWE) correct P = .05, cluster size >50) with age and gender as covariates. The hyper-arousal brain regions were measured by comparing the fALFF of PI patients and HCs. Multiple regression (P < .001, FWE correct P = .05, cluster size >50) was also performed for PI patients and HCs with group, age, and gender as covariates.The results suggested that the gender-related difference of brain activity mainly existed in superior temporal gyrus, cerebellum posterior lobe, middle frontal gyrus, and the age-related difference mainly existed in cerebellum anterior lobe, superior temporal gyrus, brainstem, parahippocampa gyrus, anterior cingulate, cingulate gyrus. In addition, the altered fALFF regions between PI and HCs mainly existed in superior temporal gyrus, posterior cingulate, anterior cingulate, cingulate gyrus, middle frontal gyrus. Furthermore, the gender factor could not influence the distribution of the altered regions. While the age factor could affect the distribution of the altered regions.

Knockdown of microRNA-17-5p Enhances the Neuroprotective Effect of Act A/Smads Signal Loop After Ischemic Injury.

Cerebral ischemic injury is a leading cause of human mortality and disability, seriously threatening human health in the world. Activin A (Act A), as a well-known neuroprotective factor, could alleviate ischemic brain injury mainly through Act A/Smads signaling. In our previous study, a noncanonical Act A/Smads signal loop with self-amplifying property was found, which strengthened the neuroprotective effect of Act A. However, this neuroprotective effect was limited due to the self-limiting behavior mediated by Smad anchor for receptor activation (SARA) protein. It was reported that microRNA-17-5p (miR-17-5p) could suppress the expression of SARA in esophageal squamous cell carcinoma. Thus we proposed that knockdown of miR-17-5p could strengthen the neuroprotective effect of Act A/Smads signal loop through SARA. To testify this hypothesis, oxygen-glucose deficiency (OGD) was introduced to highly differentiated rattus pheochromocytoma (PC12) cells. After the transfection of miR-17-5p mimic or inhibitor, the activity of Act A signal loop was quantified by the expression of phosphorylated Smad3. The results showed that suppression of miR-17-5p up-regulated the expression of SARA protein, which prolonged and strengthened the activity of Act A signaling through increased phosphorylation of downstream Smad3 and accumulation of Act A ligand. Further luciferase assay confirmed that SARA was a direct target gene of miR-17-5p. These practical discoveries will bring new insight on the endogenous neuroprotective effects of Act A signal loop by interfering a novel target: miR-17-5p.

Suppressed microRNA-96 inhibits iNOS expression and dopaminergic neuron apoptosis through inactivating the MAPK signaling pathway by targeting CACNG5 in mice with Parkinson's disease.

BACKGROUND: There have been a number of reports implicating the association of microRNAs (miRs) and the MAPK signaling pathway with the dopaminergic neuron, which is involved in the development of Parkinson's disease (PD). The present study was conducted with aims of exploring the role of miR-96 in the activation of iNOS and apoptosis of dopaminergic neuron through the MAPK signaling pathway in mice with PD. METHODS: The miR and the differentially expressed gene in PD were screened out and the relationship between them was verified. A mouse model of PD induced by MPTP and was then constructed and treated with miR-96 mimic/inhibitor and CACNG5 overexpression plasmid to extract nigral dopaminergic neuron for the purpose of detecting the effect of miR-96 on PD. The TH and iNOS positive neuronal cells, the apoptotic neuronal cells by TUNEL staining, and expression of miR-96, CACNG5, iNOS, p38MAPK, p-p38MAPK, c-Fos, Bax, and Bcl-2 in substantia nigra dopaminergic neuronal tissues were evaluated. RESULTS: The results obtained from the aforementioned procedure were then verified by cell culture of the SH-SY5Y cells, followed by treatment with miR-96 mimic/inhibitor, CACNG5 overexpression plasmid and the inhibitor of the MAPK signaling pathway. CACNG5 was confirmed as a target gene of miR-96. The inhibition of miR-96 resulted in a substantial increase in nigral cells, TH positive cells and expression of CACNG5 and Bcl-2 in nigral dopaminergic neuronal tissues, and a decrease in iNOS positive cells, apoptotic neuronal cells, and expression of iNOS, p38MAPK, p-p38MAPK, c-Fos, and Bax. CONCLUSION: The above results implicated that the downregulation of miR-96 inhibits the activation of iNOS and apoptosis of dopaminergic neuron through the blockade of the MAPK signaling pathway by promoting CACNG5 in mice with PD.

Treatment of severe periodontic-endodontic combined lesions with minocycline hydrochloride ointment combined with mineral trioxide aggregate.

Periodontic-endodontic combined lesions affect the quality of life of patients. The present study aimed to explore a way to achieve maximal effect in treating periodontic-endodontic combined lesions by using a combination of minocycline hydrochloride ointment (MHO) and mineral trioxide aggregate (MTA). In the present study, 294 patients were randomly divided into four groups: Control group, MHO group, MTA group and combination group. Endodontic and periodontic therapy was applied simultaneously on the anterior and posterior teeth of patients, and patient characteristics, gingival index (GI) and probing depth (PD) were noted when the patients were treated with the different strategies. Reexamination was performed 4 weeks after treatment and follow-up was performed 2 years later. The present study demonstrated that medical history, root filling and periapical condition within the patients were deemed as key factors in determining the success of treatment of periodontic-endodontic combined lesions. The effect of the combination treatment significantly exceeded that of either treatment alone (P<0.05). In addition, the teeth were significantly improved for patients with pathological types I, II and III in the combination group compared with either treatment group alone (P<0.05). Furthermore, compared with the MTA and MHO groups alone, the combination group demonstrated a significant decrease in PD and GI in severe periodontic-endodontic combined lesions. In conclusion, the present findings implied that combination treatment is significantly superior to single treatments applied to patients with severe periodontic-endodontic combined lesions.

Expression changes of the notch signaling pathway of PC12 cells after oxygen glucose deprivation.

Ischemic stroke is caused by obstructed blood supply to the brain. It is a common as well as a serious health problem worldwide, which is often linked to disability and mortality. Here we studied, under the conditions of oxygen glucose deprivation (OGD), the expression of Notch signaling pathway proteins in PC12 cells. PC12 cells were stimulated and converted into neuron-like cells by nerve growth factor. Exposure to OGD was used as an in vitro model of cerebral hypoxia-ischemia. Our findings demonstrate that, after 3 h of OGD exposure, the expression of Notch1, Hes1 and Hes5 significantly increased, on both mRNA and protein levels. This effect gradually reduced with continuous OGD treatment, but the expression levels of these three genes remained higher, compared to untreated controls, even after 24 h of OGD exposure. Our results suggest that OGD exposure up-regulates the expression of Notch1, Hes1 and Hes5, which are important participants in Notch signaling pathway. Since their regulatory roles appear to change dynamically with the extension of OGD, the activation of the Notch pathway may play an important role in cerebral ischemic injury.

Neuroprotective effects of Activin A on endoplasmic reticulum stress-mediated apoptotic and autophagic PC12 cell death.

Activin A, a member of the transforming growth factor-beta superfamily, plays a neuroprotective role in multiple neurological diseases. Endoplasmic reticulum (ER) stress-mediated apoptotic and autophagic cell death is implicated in a wide range of diseases, including cerebral ischemia and neurodegenerative diseases. Thapsigargin was used to induce PC12 cell death, and Activin A was used for intervention. Our results showed that Activin A significantly inhibited morphological changes in thapsigargin-induced apoptotic cells, and the expression of apoptosis-associated proteins [cleaved-caspase-12, C/EBP homologous protein (CHOP) and cleaved-caspase-3] and biomarkers of autophagy (Beclin-1 and light chain 3), and downregulated the expression of thapsigargin-induced ER stress-associated proteins [inositol requiring enzyme-1 (IRE1), tumor necrosis factor receptor-associated factor 2 (TRAF2), apoptosis signal-regulating kinase 1 (ASK1), c-Jun N-terminal kinase (JNK) and p38]. The inhibition of thapsigargin-induced cell death was concentration-dependent. These findings suggest that administration of Activin A protects PC12 cells against ER stress-mediated apoptotic and autophagic cell death by inhibiting the activation of the IRE1-TRAF2-ASK1-JNK/p38 cascade.

Efficacy and Prognostic Value of Partial Sensory Rhizotomy and Microvascular Decompression for Primary Trigeminal Neuralgia: A Comparative Study.

BACKGROUND This study aimed to compare the efficacy and prognostic value of partial sensory rhizotomy (PSR) and microvascular decompression (MVD) for primary trigeminal neuralgia (PTN). MATERIAL AND METHODS From June 2010 to June 2012, 117 patients with PTN were recruited for the study, of which 52 cases were treated with MVD (the MVD group) and 65 cases were treated with PSR (the PSR group). Visual Analog Scoring (VAS) was performed at 1 and 2 weeks, and at 1, 3, and 6 month after surgery. The overall response rate (ORR) was determined 1 month after surgery. Barrow Neurological Institute score was adopted to value the reoccurrence at 6, 12, 24, and 36 months after surgery. A 3-year follow-up was conducted and the complications were recorded. RESULTS The ORR 2 weeks after surgery in the MVD and PSR groups was 98.08% and 84.62%, respectively. One and 2 weeks after surgery, the VAS was lower in the MVD group than in the PSR group, but there was no significant difference in VAS between the 2 groups at 1, 3, and 6 months after surgery. Three years after surgery, the recurrence rate was significantly lower in the MVD group than in the PSR group. The recurrence-free survival time was longer in the MVD group than in the PSR group. The occurrence rates of herpes and total postoperative complications were significantly higher in the PSR group than in the MVD group. CONCLUSIONS Compared with PSR, MVD is more suitable for PTN treatment, with less disturbance, lower recurrence rate, and better efficacy.

Activin A/Smads signaling pathway negatively regulates Oxygen Glucose Deprivation-induced autophagy via suppression of JNK and p38 MAPK pathways in neuronal PC12 cells.

Activin A (Act A), a member of the transforming growth factor-beta (TGF-ß), reduces neuronal apoptosis during cerebral ischemia through Act A/Smads signaling pathway. However, little is known about the effect of Act A/Smads pathway on autophagy in neurons. Here, we found that oxygen-glucose deprivation (OGD)-induced autophagy was suppressed by exogenous Act A in a concentration-dependent manner and enhanced by Act A/Smads pathway inhibitor (ActRIIA-Ab) in neuronal PC12 cells. These results indicate that Act A/Smads pathway negatively regulates autophagy in OGD-treated PC12 cells. In addition, we found that c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein (MAP) kinase pathways are involved in the OGD-induced autophagy. The activation of JNK and p38 MAPK pathways in OGD-treated PC12 cells was suppressed by exogenous Act A and enhanced by ActRIIA-Ab. Together, our results suggest that Act A/Smads signaling pathway negatively regulates OGD-induced autophagy via suppression of JNK and p38 MAPK pathways in neuronal PC12 cells.

Noncanonical Activin A Signaling in PC12 Cells: A Self-Limiting Feedback Loop.

Activin A (Act A), a member of transforming growth factor-ß superfamily, plays a neuroprotective role in multiple neurological diseases through Act A/Smads signal activation. Traditionally, the up-regulation of Act A gene and extracellular Act A accumulation show the signal activation as a linear pathway. However, one of our discoveries indicated that Act A could lead a loop signaling in ischemic injury. To clarify the characteristic of this loop signaling in a non-pathological state, we up-regulated the expression of Act A, monitored extracellular Act A accumulation and examined the activity of Act A signaling, which was quantified by the expression of phosphorylated Smad3 and the fluorescence intensity of Smad4 in nuclei. The results demonstrated a noncanonical Act A signal loop with self-amplifying property in PC12 cells. Further, it showed self-limiting behavior due to temporary activation and spontaneous attenuation. This periodic behavior of Act A signal loop was found to be regulated by the level of Smad anchor for receptor activation (SARA). Moreover, increased activity of Act A signal loop could promote PC12 cell proliferation and enhance the survival rate of cells to Oxygen-Glucose Deprivation. These practical discoveries will bring new insight on the functional outcome of Act A signaling in neurological diseases by the further understanding: loop signaling.

The role of Rho/Rho-kinase pathway and the neuroprotective effects of fasudil in chronic cerebral ischemia.

The Rho/Rho-kinase signaling pathway plays an important role in cerebral ischemia/reperfusion injury. However, very few studies have examined in detail the changes in the Rho/Rho-kinase signaling pathway in chronic cerebral ischemia. In this study, rat models of chronic cerebral ischemia were established by permanent bilateral common carotid artery occlusion and intragastrically administered 9 mg/kg fasudil, a powerful ROCK inhibitor, for 9 weeks. Morris water maze results showed that cognitive impairment progressively worsened as the cerebral ischemia proceeded. Immunohistochemistry, semi-quantitative RT-PCR and western blot analysis showed that the expression levels of Rho-kinase, its substrate myosin-binding subunit, and its related protein alpha smooth muscle actin, significantly increased after chronic cerebral ischemia. TUNEL staining showed that chronic cerebral ischemia could lead to an increase in neuronal apoptosis, as well as the expression level of caspase-3 in the frontal cortex of rats subjected to chronic cerebral ischemia. Fasudil treatment alleviated the cognitive impairment in rats with chronic cerebral ischemia, and decreased the expression level of Rho-kinase, myosin-binding subunit and alpha smooth muscle actin. Furthermore, fasudil could regulate cerebral injury by reducing cell apoptosis and decreasing caspase-3 expression in the frontal cortex. These findings demonstrate that fasudil can protect against cognitive impairment induced by chronic cerebral ischemia via the Rho/Rho-kinase signaling pathway and anti-apoptosis mechanism.

Computer-Based Cognitive Programs for Improvement of Memory, Processing Speed and Executive Function during Age-Related Cognitive Decline: A Meta-Analysis.

BACKGROUND: Several studies have assessed the effects of computer-based cognitive programs (CCP) in the management of age-related cognitive decline, but the role of CCP remains controversial. Therefore, this systematic review evaluated the evidence on the efficacy of CCP for age-related cognitive decline in healthy older adults. METHODS: Six electronic databases (through October 2014) were searched. The risk of bias was assessed using the Cochrane Collaboration tool. The standardized mean difference (SMD) and 95% confidence intervals (CI) of a random-effects model were calculated. The heterogeneity was assessed using the Cochran Q statistic and quantified with the I2 index. RESULTS: Twelve studies were included in the current review and were considered as moderate to high methodological quality. The aggregated results indicate that CCP improves memory performance (SMD, 0.31; 95% CI 0.16 to 0.45; p < 0.0001) and processing speed (SMD, 0.50; 95% CI 0.14 to 0.87; p = 0.007) but not executive function (SMD, -0.12; 95% CI -0.33 to 0.09; p = 0.27). Furthermore, there were long-term gains in memory performance (SMD, 0.59; 95% CI 0.13 to 1.05; p = 0.01). CONCLUSION: CCP may be a valid complementary and alternative therapy for age-related cognitive decline, especially for memory performance and processing speed. However, more studies with longer follow-ups are warranted to confirm the current findings.

Finasteride reduces microvessel density and expression of vascular endothelial growth factor in renal tissue of diabetic rats.

BACKGROUND: Vascular endothelial growth factor (VEGF) plays a critical role in the pathogenesis of diabetic microvascular complications. Finasteride has been confirmed to decrease VEGF expression in prostate and prostatic suburethral tissue resulting in limiting hematuria from human benign prostatic hyperplasia. The purpose of this study was to evaluate the effects of finasteride on microvessel density (MVD), VEGF protein and mRNA expressions in the renal tissue of diabetic rats. METHODS: Diabetic rats induced by streptozotocin were intragastrically given finasteride at 30 mg/kg body weight once a day for 4 weeks. Histomorphologic changes in kidney were observed under light microscope. Immunohistochemistry for CD34 and VEGF on kidney sections was performed to assess MVD and VEGF protein expression in glomeruli of rats, respectively. The VEGF mRNA expression in the renal tissue was examined using reverse transcription polymerase chain reaction analysis. RESULTS: The glomerular tuft area, glomerular volume, MVD, VEGF protein expression in glomeruli and VEGF mRNA expression in the renal cortex tissue were significantly increased in diabetic rats and finasteride-treated rats when compared with controls (P < 0.01, P < 0.05). When compared with diabetic rats, the glomerular tuft area, glomerular volume, MVD, VEGF protein expression in glomeruli and VEGF mRNA expression in the renal cortex tissue of finasteride-treated rats were significantly decreased (P < 0.05, P < 0.01). CONCLUSIONS: Finasteride reduces the VEGF expression and decreases the MVD in the renal tissue of diabetic rats, suggesting the therapeutic potential of finasteride on diabetic microvascular complications.

Pin1, endothelial nitric oxide synthase, and amyloid-ß form a feedback signaling loop involved in the pathogenesis of Alzheimer's disease, hypertension, and cerebral amyloid angiopathy.

Although the molecular mechanism has not yet been clarified until now, it is very interesting that Alzheimer's disease (AD), hypertension (HTN), and cerebral amyloid angiopathy (CAA) often occur synchronously and possess many similar pathological characteristics. Herein, we hypothesize that a feedback signaling loop, consisted of Pin1, endothelial nitric oxide synthase (eNOS), and amyloid-ß (Aß), may contribute to the interesting pathological phenomenon. First, Pin1 inhibits the production of Aß, and enhances the activity of eNOS. Second, Aß and eNOS form a mutual inhibition system. Third, the well-balanced feedback signaling loop avoids the development of AD, HTN, and CAA by inhibiting the frequent pathological characteristics of these diseases, including Aß deposition in cerebral microvessels and cerebral microbleeds. On one hand, Pin1 and eNOS not only inhibit Aß production but also accelerate Aß clearance, preventing Aß deposition in cerebral microvessels. On the other hand, Pin1 and eNOS promote vasodilatation and prevent the elevation of blood pressure in brain, alleviating the pathology of cerebral microbleeds. However, once the precise balance is disturbed, it may result in Aß deposition, microbleeds, and elevated blood pressure, possibly leading to the synchronous occurrence of AD, HTN, and CAA. The hypothesis updates the current understanding of the molecular linkage among AD, HTN, and CAA, and lays the ground for developing combined prevention, diagnosis, and treatment of these diseases more efficiently and more economically. Interestingly, biotechnical medicines enhancing the activity of Pin1 and/or eNOS may prevent the development of AD, HTN, and CAA, and targeting Aß deposition may alleviate the clinical pathologies of these related diseases.

Endogenous protection derived from activin A/Smads transduction loop stimulated via ischemic injury in PC12 cells.

Activin A (ActA), a member of transforming growth factor-beta (TGF-b) super- family, affects many cellular processes, including ischemic stroke. Though the neuroprotective effects of exogenous ActA on oxygen-glucose deprivation (OGD) injury have already been reported by us, the endogenous role of ActA remains poorly understood. To further define the role and mechanism of endogenous ActA and its signaling in response to acute ischemic damage, we used an OGD model in PC12 cells to simulate ischemic injury on neurons in vitro. Cells were pre-treated by monoclonal antibody against activin receptor type IIA (ActRII-Ab). We found that ActRII-Ab augments ischemic injury in PC12 cells. Further, the extracellular secretion of ActA as well as phosphorylation of smad3 in PC12 cells was also up-regulated by OGD, but suppressed by ActRII-Ab. Taken together, our results show that ActRII-Ab may augment ischemic injury via blocking of transmembrane signal transduction of ActA, which confirmed the existence of endogenous neuroprotective effects derived from the ActA/Smads pathway. ActRIIA plays an important role in transferring neuronal protective signals inside. It is highly possible that ActA transmembrance signaling is a part of the positive feed-back loop for extracellular ActA secretion.

Effects of SARA on oxygen-glucose deprivation in PC12 cell line.

Ischemic stroke is a major composition of cerebrovascular disease, seriously threatening to human health in the world. Activin A (ActA), belonging to transforming growth factor-beta (TGF-ß) super family, plays an important role in the hypoxic-ischemic brain injury through ActA/Smads pathway. While as an essential phosphorylation assistor in TGF-ß signaling, the functions and mechanisms of smad anchor for receptor activation (SARA) in ischemic brain injury remain poorly understood. To solve this problem and explore the pathological processes of ischemic stroke, we used an Oxygen-Glucose deprivation (OGD) model in nerve growth factor-induced differentiated rattus PC12 pheochromocytoma cells and down regulated the expressions of SARA by RNA interference technology. Our results showed that the repression of SARA before OGD exposure reduced the expressions of Smad2, 3, 4 mRNA and the phosphorylation rate of Smad2 protein, but it did not affect the mRNA expressions of Smad7. After OGD treatment, ActA/Smads pathway was activated and the expression of SARA in the SARA pre-repression group was significantly up-regulated. The pre-repression of SARA increased the sensitivities of nerve-like cells to OGD damage. Moreover, the mRNA expression of Smad7 which was supposed to participate in the negative feedback of ActA/Smads pathway was also elevated due to OGD injury. Taken together, these results suggest a positive role of SARA in assisting the phosphorylation of Smad2 and maintaining the neuron protective effect of ActA/Smads pathway.

Neuroprotective effects of exogenous activin A on oxygen-glucose deprivation in PC12 cells.

Ischemic cerebrovascular disease is one of the most common causes of death in the World. Exogenous activin A (ActA) protects neurons against toxicity and plays a central role in regulating the brain's response to injury. In the present study, we investigated the mechanisms involved in the neuroprotective effects of ActA in a model of hypoxic-ischemic brain disease. We found that ActA could effectively increase the survival rate of PC12 cells and relieve oxygen-glucose deprivation (OGD) damage. To clarify the neuroprotective mechanisms of ActA, the effects of ActA on the ActA/Smad pathway and on the up-regulation of inducible nitric oxide synthase (NOS) and superoxide dismutase (SOD) were investigated using OGD in PC12 cells. The results showed that ActA could increase the expression of activin receptor IIA (ActRIIA), Smad3 and Smad4 and that 50 ng/mL and 100 ng/mL of ActA could reduce NO levels and increase SOD activity by 78.9% and 79.9%, respectively. These results suggested that the neuroprotective effects of ActA in ischemia could be related to the activation of the ActA/Smad signaling pathway and to its anti-oxidant activities.