Search

Our previous studies have shown evidence of endoplasmic reticulum (ER) stress-induced apoptosis in the hippocampus and mPFC in an animal model of post- traumatic stress disorder (PTSD). Inositol-requiring enzyme 1α (IRE1α) and its downstream molecule X-box binding protein 1 (XBP1) play key roles in the ER-related apoptosis pathway. Dysregulation of the locus coeruleus (LC) has been reported to contribute to cognitive and/or arousal impairments associated with PTSD. The aim of the present study was to explore the role of IRE1α pathway in neuronal apoptosis in the LC of rat models of PTSD. We used an acute exposure to prolonged stress (single prolonged stress, SPS) to model PTSD in rats and examined the effects related to the IRE1α pathway. Neuronal apoptosis in LC was detected by transmission electron microscopy and TUNEL staining. The results showed that the level of LC neuronal apoptosis was markedly increased after SPS. SPS exposure triggered IRE1α pathway, as evidenced by the increased activity of IRE1α, specific splicing of XBP1, and up-regulated expression of binding immunoglobulin protein/78 kDa glucose-regulated protein (BiP/GRP78), and C/EBP-homologous protein (CHOP). Treatment with STF-083010, an IRE1α RNase-specific inhibitor, successfully attenuated the above changes. These results indicate that excessive activation of the ER stress-associated IRE1α pathway is involved in LC neuronal apoptosis induced by SPS exposure; this may be a crucial mechanism of the pathogenesis of PTSD. [ABSTRACT FROM AUTHOR]

Abstract: Post-traumatic stress disorder (PTSD) is a stress-related mental disorder caused by experience of a traumatic event, and presents with characteristic symptoms including intrusive memories, hyperarousal, and avoidance. Recently, structural neuroimaging studies showed that hippocampal volumes were relatively low in PTSD patients. However, the mechanisms that cause such atrophy are not well understood. The aim of this study was to reveal the possible mechanisms involved in apoptosis induced by single-prolonged stress (SPS) in hippocampus of PTSD rats. SPS is one of the animal models proposed for PTSD. Rats exposure to SPS showed enhanced inhibition of the hypothalamo-pituitary-adrenal (HPA) axis, which has been reliably reproduced in patients with PTSD. Wistar rats were killed at 1, 4, 7, 14 and 28 days after exposure to SPS. Expression of caspase-9, caspase-3, cytochrome c, Bcl-2 and Bax was detected by immunohistochemistry, immunofluorescence, Western blotting and electron microscopy. Apoptotic cells were assessed by TUNEL method. Our results showed apoptotic cells were significantly increased in hippocampus of SPS rats, accompanied by release of cytochrome c from the mitochondria into the cytosol, increase of caspase-9 and caspase-3 expression and decrease of the Bcl-2/Bax ratio. The results indicate that SPS-induced apoptosis in hippocampus of PTSD rats, and the mitochondrial pathway was involved in the process of SPS-induced apoptosis. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To detect the apoptosis-related Bax and Bcl-2 gene expression and apoptotic cell death in the amygdala region in the single-prolonged stress (SPS) rats. Methods: A total of 100 male Wistar rats were randomly divided into a normal control group and SPS groups of 1d, 4d, 7d, and 14d. The expression of Bax and Bcl-2 was detected using immunohistochemistry and Western Blotting; TUNEL-staining and double-labeled flow cytometry (FCM) were employed for the detection and quantification of the apoptotic cells in the amygdala; morphological change of the subcellular structure in amygdala was observed by using the transmission electron microscopy (TEM). Results: The ratio of Bax/Bcl-2 peaked at SPS 4d and then gradually decreased. The apoptosis peaked at SPS 4d. The TUNEL-positive cells were found in each SPS group and the TUNEL-positive cells rate peaked at SPS 4d. The morphological change of amygdala cells in each SPS group bears typical apoptotic characteristics. Conclusions: In the SPS rat brain, we found apoptotic process in the amygdala region which may relate to the pathogenesis of amygdala abnormal function in PTSD. [Copyright &y& Elsevier]

Background: Ras and Rab interactor 1 (Rin1) is predominantly expressed in memory-related brain regions, and has been reported to play an important role in fear memory. Increased expression of Rin1 in an animal model of posttraumatic stress disorder (PTSD) has been associated with enhanced acquisition of fear memories, but the exact mechanism of Rin1 in memory regulation are not clear.Methods: Here, we used Rin1-knockout rats to examine the effect of Rin1 on fear memories by fear conditional test and the molecular mechanisms that regulate these effects by immunofluorescence, western blotting and TUNEL.Results: Our results show that Rin1-knockout rats have a deficit in formation and extinction of Auditory fear memories. Lack of Rin1 results in enhanced apoptosis in the hippocampus through a pathway related to the mitochondria rather than the endoplasmic reticulum-related pathway. Importantly, the lack of Rin1 induces a decrease in α-amino-3‑hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) found in the cytoplasm, but not in those found in the membrane. Expression of CaMKII (which is important for insertion of cytoplasmic AMPAR into the membrane) and stargazin (which is important for immobilization of AMPAR in the membrane) was not changed. The lack of Rin1 also induced changes in AMPAR distribution, from diffuse spread in the cells to clusters around the edge of the cell. Additionally, clustered AMPAR distribution showed a high degree of overlap with actin distribution.Conclusion: These findings indicate that Rin1 affects not only apoptosis, but also the concentration and distribution pattern of AMPAR, which are important in the formation and extinction of fear memory. [ABSTRACT FROM AUTHOR]

Post-traumatic stress disorder (PTSD) is a stress-related mental disorder which occurs following exposure to traumatic events. A number of brain neuroimaging studies have revealed that PTSD patients have reduced volume and abnormal functions in the hippocampus and the amygdala. However, the pathogenesis of abnormalities in certain brain regions, as induced by PTSD, remains unclear. Recent studies, using the single prolonged stress (SPS) model, an animal model of PTSD, have found that abnormal apoptosis in certain brain regions, including the hippocampus, the amygdala, and the medial prefrontal cortex (mPFC); these areas are closely associated with emotion and cognition. In this review, we summarize the mechanism of apoptosis in SPS rats, including the endoplasmic reticulum (ER) and the mitochondria pathways. For the ER pathway, three individual pathways: PERK, IRE1, and ATF6 showed different roles on apoptosis and neuroprotection. Three key factors are thought to be involved in the mitochondrial pathway and PTSD-induced apoptosis: corticosteroid receptors, apoptosis-related factors, and anti-apoptosis factors. We have investigated the role of these factors and have attempted to identify which factors of the pathways are more focused towards neuronal protection, and which are more direct towards apoptosis. We also discussed the role of autophagy and the specific differences between autophagy and apoptosis in SPS rats. Finally, we discussed emerging researches related to anti-apoptosis treatment, including PERK inhibitors, IRE1 inhibitors, and metformin; collectively, these were exciting, but limited, This review provides a summary of the current understanding of apoptosis in SPS rats and the potential anti-apoptosis treatment strategies for PTSD. [ABSTRACT FROM AUTHOR]

Qingyihuaji Formula (QYHJ), a widely used traditional Chinese medicine (TCM), has been used to treat patients with cancer in China. However, the effect and mechanism of QYHJ on pancreatic ductal adenocarcinoma (PDAC) remains unclear. This study aimed to explore the roles and evaluate the possible underlying molecular mechanisms of QYHJ and its core component in PDAC using label-free quantitative proteomics in conjunction with network pharmacology-based analysis. By screening differentially expressed proteins (DEPs) in proteomics and QYHJ-predicted gene sets, we identified QYHJ-related PDAC targets annotated with bioinformatic analysis. A subcutaneous tumor model was established to assess the role of QYHJ in vivo. The effects of quercetin (Que), a core component of QYHJ, on cell proliferation, migration, invasion, apoptosis, and autophagy in SW1990 and PANC-1 cells were investigated in vitro. Immunohistochemistry, western blotting, mRFP-GFP-LC3 adenovirus, and kinase analysis were used to determine the underlying mechanisms. Bioinformatics analysis revealed that 41 QYHJ-related PDAC targets were closely related to the cellular response to nitrogen compounds, positive regulation of cell death, regulation of epithelial cell apoptotic processes, and chemokine signaling pathways. CASP3, SRC, STAT1, PTPN11, PKM, and PAK1 with high expression were identified as hub DEPs in the PPI network, and these DEPs were associated with poor overall survival and STAT 1, MAPK/ERK, and PI3K/Akt/mTOR signaling pathways in PDAC patients. QYHJ significantly promoted tumor death in nude mice. Moreover, quercetin inhibited the proliferation, migration, and invasion of PDAC cells. Additionally, Que induced apoptosis and autophagy in PDAC cells. Mechanistically, QYHJ and Que significantly activated STAT 1 and remarkably inhibited the MAPK/ERK and PI3K/Akt/mTOR signaling pathways in vivo and in vitro , respectively. Importantly, ERK1/2 inactivation contributes to que-induced apoptosis in SW1990 and PANC-1 cells. These results suggest that QYHJ and Que are promising anti-PDAC avenues that benefit from their multiform mechanisms. [Display omitted] • QYHJ significantly promoted tumor death in nude mice. • Que inhibited the proliferation, migration, and invasion of PDAC cells. • Que induced apoptosis and autophagy in PDAC cells. • ERK1/2 inactivation contributed to Que-induced cell apoptosis in PDAC cells. [ABSTRACT FROM AUTHOR]

Apoptosis of DA neurons is a contributing cause of disability and death for Parkinson’s disease (PD). Akt may become a potential therapeutic target for PD since Akt has been deactivated during DA neuron apoptosis. We previously demonstrated that Akt confers apoptosis resistance against 6-OHDA in DA neuron-like PC12 cells, yet the underlying mechanisms accounted for this are not fully understood. Here we report that microRNA-130b (miR-130b)-dependent and cylindromatosis (CYLD) repression-mediated Akt ubiquitination renders apoptosis resistance of PC12 cells to 6-OHDA, which elicits histone H3 deacetylation-induced transcriptional downregulation of miR-130b vice versa. CYLD deficiency ubiquitinates Akt at Lys63, thereby phosphorylating Akt and antagonizing 6-OHDA-initiated apoptosis. MiR-130b targetedly represses CYLD and increases apoptosis resistance to 6-OHDA. CYLD repression by miR-130b restores Akt ubiquitination and activation, GSK3β and FoxO3a phosphorylation, FoxO3a removal from Bim promoter as well as Bim downregulation during 6-OHDA administration. CYLD deficiency-mediated Akt activation is instrumental for the apoptosis-resistant phenotypes of miR-130b. In addition, 6-OHDA transcriptionally downregulates miR-130b through recruitment of HDAC3 at the promoter. Furthermore, EPO potentiates the ability of miR-130b to activate Akt and augment apoptosis resistance. Our findings identify the apoptosis-resistant function of miR-130b and suggest that histone H3 deacetylation plays a pivotal role in regulating miR-130b transcription in response to 6-OHDA. [ABSTRACT FROM AUTHOR]

Neuronal apoptosis is a contributing cause of disability and death in cerebral ischemia. Nuclear factor-κB (NF-κB) may become a potential therapeutic target for hypoxic/ischemic neuron damage because NF-κB is inactivated after hypoxia exposure. Vascular endothelial growth factor (VEGF) has been found to improve neurological function recovery in cerebral ischemic injury although the exact molecular mechanisms that underlie the neuroprotective function of VEGF remain largely unknown. Here we defined the mechanism by which VEGF antagonized neuron-like PC12 cells apoptosis induced by hypoxia mimetic agent cobalt chloride (CoCl 2 ) is through restoration of NF-κB activity. Depletion of VEGF with small interfering RNA (siRNA) in PC12 cells conferred CoCl 2 -induced cytotoxicity which was mitigated by VEGF administration. Treatment of PC12 cells with VEGF attenuated the CoCl 2 -induced cytotoxicity in both dose- and time-dependent manner. Mechanistically, VEGF increased IκBα phosphorylation and ubiquitination, promoted P65 nuclear translocation as well as upregulated XIAP and CCND1 expression. Meanwhile, VEGF administration reversed the dysregulation of IκBα phosphorylation and ubiquitination, P65 nuclear translocation as well as XIAP and CCND1 expression induced by CoCl 2 . Notably, the VEGF-dependent cytoprotection was abolished by pretreatment with BAY 11-7085, a specific inhibitor of NF-κB. Our data suggest that VEGF/NF-κB signalling pathway represents an adaptive mechanism that protects neural cells against hypoxic damage. [ABSTRACT FROM AUTHOR]

Our previous study demonstrated that transforming growth factor (TGF)-β activates β-catenin signaling through Smad3 interaction with β-catenin in chondrocytes. In the present studies, we further investigated the detailed molecular mechanism of the cross-talk between TGF-β/Smad3 and Wnt/β-catenin signaling pathways. We found that C-terminal Smad3 interacted with both the N-terminal region and the middle region of β-catenin protein in a TGF-IJ-dependent manner. Both Smad3 and Smad4 were required for the interaction with β-catenin and protected β-catenin from an ubiquitin-proteasome-dependent degradation. In addition, the formation of the Smad3-Smad4-βcatenin protein complex also mediated β-catenin nuclear translocation. This Smad3-mediated regulatory mechanism of β-catenin protein stability enhanced the activity of β-catenin to activate downstream target genes during chondrogenesis. Our findings demonstrate a novel mechanism between TGF-β and Wnt/β-catenin signaling pathways during chondrocyte development. [ABSTRACT FROM AUTHOR]