Death-associated protein kinase 1 is associated with cognitive dysfunction in major depressive disorder

We previously showed that death-associated protein kinase 1(DAPK1)expression is increased in hippocampal tissue in a mouse model of major depressive disorde and is related to cognitive dysfunction in Alzheimer's disease.In addition,depression is a risk factor for developing Alzheimer's disease,as well as an early clinical manifestation of Alzheimer's disease.Meanwhile,cognitive dysfunction is a distinctive feature of major depressive disorder.Therefore,DAPK1 may be related to cognitive dysfunction in major depressive disorder.In this study,we established a mouse model of major depressive disorder by housing mice individually and exposing them to chronic,mild,unpredictable stressors.We found that DAPK1 and tau protein levels were increased in the hippocampal CA3 area,and tau was hyperphosphorylated at Thr231,Ser262,and Ser396 in these mice.Furthermore,DAPK1 shifted from axonal expression to overexpression on the cell membrane.Exercise and treatment with the antidepressant drug citalopram decreased DAPK1 expression and tau protein phosphorylation in hippocampal tissue and improved both depressive symptoms and cognitive dysfunction.These results indicate that DAPK1 may be a potential reason and therapeutic target of cognitive dysfunction in major depressive disorder.

Computational Screening of Novel Mitogen-activated Protein Kinase Kinase-1 （MEK1） Inhibitors by Docking and Scoring

The mitogen-activated protein kinase （MAPK） cell signal transduction pathways play a key role in determining the survival of cells. If these pathways can be controlled, they will prohibit the proliferation of cancer cells. To attain this goal, the authors utilize many drugs to interact with mitogen-activated protein kinase kinase-1 （MEK1） in MAPK, and use computer aided drug design （CADD） to analyze the ligand activities of proteins in MEKL The results show that in these drugs, the aromatic group in the terminal of the protein and the PHE209 will induce the stacking force, which is highly related to the actual activities of these drugs.

Electroacupuncture preconditioning protects against focal cerebral ischemia/reperfusion injury via suppression of dynamin-related protein 1

Electroacupuncture preconditioning at acupoint Baihui （GV20） can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynamin-related protein 1 （Drp1） can trigger neuronal apoptosis following cerebral ischemia/reperfusion injury. Herein, we examined the hypothesis that electroacupuncture pretreatment can regulate Drp1, and thus inhibit mitochondrial fission to provide cerebral protection. Rat models of focal cerebral ischemia/reperfusion injury were established by middle cerebral artery occlusion at 24 hours after 5 consecutive days of preconditioning with electroacupuncture at GV20 （depth 2 mm, intensity 1 mA, frequency 2/15 Hz, for 30 minutes, once a day）. Neurological function was assessed using the Longa neurological deficit score. Pathological changes in the ischemic penumbra on the injury side were assessed by hematoxylin-eosin staining. Cellular apoptosis in the ischemic penumbra on the injury side was assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling staining. Mitochondrial ultrastructure in the ischemic penumbra on the injury side was assessed by transmission electron microscopy. Drp1 and cytochrome c expression in the ischemic penumbra on the injury side were assessed by western blot assay. Results showed that electroacupuncture preconditioning decreased expression of total and mitochondrial Drp1, decreased expression of total and cytosolic cytochrome c, maintained mitochondrial morphology and reduced the proportion of apoptotic cells in the ischemic penumbra on the injury side, with associated improvements in neurological function. These data suggest that electroacupuncture preconditioning-induced neuronal protection involves inhibition of the expression and translocation of Drp1.

Multiple implications of 3-phosphoinositide-dependent protein kinase 1 in human cancer

3-phosphoinositide-dependent protein kinase-1(PDK1) is a central mediator of cellular signaling between phosphoinositide-3 kinase and various intracellular serine/threonine kinases,including protein kinase B,p70 ribosomal S6 kinase,serum and glucocorticoid-inducible kinase,and protein kinase C.PDK1 activates members of the AGC family of protein kinases by phosphorylating serine/threonine residues in the activation loop.Here,we review the regulatory mechanisms of PDK1 and its roles in cancer.PDK1 is activated by autophosphorylation in the activation loop and other serine residues,as well as by phosphorylation of Tyr-9 and Tyr-373/376.Src appears to recognize PDK1 following tyrosine phosphorylation.The role of heat shock protein 90 in regulating PDK1 stability and PDK1-Src complex formation are also discussed.Furthermore,we summarize the subcellular distribution of PDK1.Finally,an important role for PDK1 in cancer chemotherapy is proposed.In conclusion,a better understanding of its molecular regulatory mechanisms in various signaling pathways will help to explain how PDK1 acts as an oncogenic kinase in various cancers,and will contribute to the development of novel cancer chemotherapies.

Methylation of DAPK and THBS1 genes in esophageal gastric-type columnar metaplasia

AIM: To explore methylation of DAPK, THBS1, CDH-1, and p14 genes, and Helicobacter pylori(H. pylori) status in individuals harboring esophageal columnar metaplasia.METHODS: Distal esophageal mucosal samples obtained by endoscopy and histologically diagnosed as gastric-type(non-specialized) columnar metaplasia, were studied thoroughly. DNA was extracted from paraffin blocks, and methylation status of deathassociated protein kinase(DAPK), thrombospondin-1(THBS1), cadherin-1(CDH1), and p14 genes, was examined using a methyl-sensitive polymerase chain reaction(MS-PCR) and sodium bisulfite modification protocol. H. pylori cag A status was determined by PCR.RESULTS: In total, 68 subjects(33 females and 35 males), with a mean age of 52 years, were included. H. pylori cag A positive was present in the esophageal gastric-type metaplastic mucosa of 18 individuals. DAPK, THSB1, CDH1, and p14 gene promoters were methylated by MS-PCR in 40(58.8%), 33(48.5%), 46(67.6%), and 23(33.8%) cases of the 68 esophageal samples. H. pyloristatus was associated with methylation of DAPK(P = 0.003) and THBS1(P = 0.019).CONCLUSION: DNA methylation occurs in cases of gastric-type(non-specialized) columnar metaplasia of the esophagus, and this modification is associated with H. pylori cag A positive infection.

Influence of DAP1 Genotype and Psychosocial Factors on Posttraumatic Stress Disorder in Thai Tsunami Survivors: A GxE Approach

Background: Posttraumatic Stress Disorder (PTSD) is a psychiatric disorder found in individuals afflicted by a traumatic event including the natural disaster. “Tsunami” occurred in Andaman coast of Thailand on December 26, 2004, in which 33.6% of survivors were diagnosed as PTSD. This study aimed to explore the single nucleotide polymorphism (SNP). rs267943 genotype is located on chromosome 5 in the intron of the death-associated protein 1 (DAP1) gene and psychosocial factors for PTSD. Methods: Participants (N = 1970) were recruited from volunteers who have complete data both of DAP1 gene and psychosocial factor. Results: Using a binary logistic regression model, significant gene-environment interactions were found for the single nucleotide polymorphism (SNP) rs267943 and psychosocial factors including depression (adj. OR = 6.0, 95% CI = 4.29 - 8.39), neurotic personality (adj. OR = 2.73, 95% CI = 2.18 - 3.42), planning (adj. OR = 1.52, 95% CI = 1.20 - 1.93), use of emotional support (adj. OR = 1.32, 95% CI = 1.21 - 1.94) with statistical significant p Conclusion: This study demonstrated that GxE studies can be utilized to shed light on the origins of PTSD.

PGK1-coupled HSP90 stabilizes GSK3βexpression to regulate the stemness of breast cancer stem cells

Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanisms of GSK3βprotein expression remain elusive.Methods:Co-immunoprecipitation and mass spectral assays were performed to identify molecules binding to GSK3β,and to characterize the interactions of GSK3β,heat shock protein 90(Hsp90),and co-chaperones.The role of PGK1 in Hsp90 chaperoning GSK3βwas evaluated by constructing 293T cells stably expressing different domains/mutants of Hsp90α,and by performing a series of binding assays with bacterially purified proteins and clinical specimens.The influences of Hsp90 inhibitors on breast cancer stem cell stemness were investigated by Western blot and mammosphere formation assays.Results:We showed that GSK3βwas a client protein of Hsp90.Hsp90,which did not directly bind to GSK3β,interacted with phosphoglycerate kinase 1 via its C-terminal domain,thereby facilitating the binding of GSK3βto Hsp90.GSK3β-bound PGK1 interacted with Hsp90 in the“closed”conformation and stabilized GSK3βexpression in an Hsp90 activity-dependent manner.The Hsp90 inhibitor,17-AAG,rather than HDN-1,disrupted the interaction between Hsp90 and PGK1,and reduced GSK3βexpression,resulting in significantly reduced inhibition ofβ-catenin expression,to maintain the stemness of breast cancer stem cells.Conclusions:Our findings identified a novel regulatory mechanism of GSK3βexpression involving metabolic enzyme PGK1-coupled Hsp90,and highlighted the potential for more effective cancer treatment by selecting Hsp90 inhibitors that do not affect PGK1-regulated GSK3βexpression.

AMPK-associated signaling to bridge the gap between fuel metabolism and hepatocyte viability

The adenosine monophosphate-activated protein kinase (AMPK) and p70 ribosomal S6 kinase-1 pathway may serve as a key signaling flow that regulates energy metabolism; thus, this pathway becomes an attractive target for the treatment of liver diseases that result from metabolic derangements. In addition, AMPK emerges as a kinase that controls the redox-state and mitochondrial function, whose activity may be modulated by antioxidants. A close link exists between fuel metabolism and mitochondrial biogenesis. The relationship between fuel metabolism and cell survival strongly implies the existence of a shared signaling network, by which hepatocytes respond to challenges of external stimuli. The AMPK pathway may belong to this network. A series of drugs and therapeutic candidates enable hepatocytes to protect mitochondria from radical stress and increase cell viability, which may be associated with the activation of AMPK, liver kinase B1, and other molecules or components. Consequently, the components downstream of AMPK may contribute to stabilizing mitochondrial membrane potential for hepatocyte survival. In this review, we discuss the role of the AMPK pathway in hepatic energy metabolism and hepatocyte viability. This information may help identify ways to prevent and/or treat hepatic diseases caused by the metabolic syndrome. Moreover, clinical drugs and experimental therapeutic candidates that directly or indirectly modulate the AMPK pathway in distinct manners are discussed here with particular emphasis on their effects on fuel metabolism and mitochondrial function.

Involvement of the Wnt signaling pathway and cell apoptosis in the rat hippocampus following cerebral ischemia/reperfusion injury

We investigated the role of the Wnt signaling pathway in cerebral ischemia/reperfusion injury by examining β-catenin and glycogen synthase kinase-3β protein expression in the rat hippocampal CA1 region following acute cerebral ischemia/reperfusion. Our results demonstrate that cell apoptosis increases in the CA1 region following ischemia/reperfusion. In addition, β-catenin and glycogen synthase kinase-3β protein expression gradually increases, peaking at 48 hours following reperfusion. Dickkopf-1 administration, after cerebral ischemia/reperfusion injury, results in decreased cell apoptosis, and β-catenin and glycogen synthase kinase-3β expression, in the CA1 region. This suggests that β-catenin and glycogen synthase kinase-3β, both components of the Wnt signaling pathway, participate in cell apoptosis following cerebral ischemia/reperfusion injury.

Genome-Wide Association Study in Thai Tsunami Survivors Identified Risk Alleles for Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a psychiatric disorder found in individuals afflicted by a traumatic event. Multiple environmental and genetic factors can contribute to PTSD susceptibility. Since it is rare to find members of the same family afflicted by the same catastrophic event, it is not practical to determine PTSD susceptibility genes by a gene linkage analysis. A natural disaster, such as the 2004 Tsunami, provided us with a rare chance for a genetic analysis of PTSD. To identify SNPs associated with PTSD susceptibility, we conducted a genome-association study (GWAS) in Thai-Tsunami survivors. Initial phase of the study with 396 chronic PTSD patients and 457 controls, we identified top ninety SNPs (P -4), which were further assessed in the second phase with 395 chronic PTSD patients and 798 controls. Two SNPs (rs267950 and rs954406), were identified in the second phase, and subjected to fine mapping using a data set from both phases. SNP rs267943 showed the strongest association with PTSD susceptibility and was in complete linkage disequilibrium with SNP rs267950 with P = 6.15 × 10-8, OR = 1.46 and 95% CI = 1.19 - 1.79, reaching genome-wide significance. SNP rs267943 is located on chromosome 5 in the intron of the death-associated protein 1 (DAP1) gene and, when linked to a synthetic promoter, could regulate transcription. To our knowledge, this is the first GWAS for PTSD susceptibility in an Asian population which could provide an important insight into the genetic contribution of PTSD and may lead to new treatment strategies for PTSD.

USP10 Alleviates Palmitic Acid-induced Steatosis through Autophagy in HepG2 Cells

Background and Aims:Nonalcoholic fatty liver disease(NAFLD)is a common chronic liver disease caused by overnutrition.Impaired autophagy is closely related to NAFLD progression.Recently,ubiquitin-specific peptidase-10(USP10)was reported to ameliorate hepatic steatosis,but the underlying mechanism is still unclear.In view of the potential effects of USP10 on autophagy,we investigated whether USP10 alleviated steatosis through autophagy.Methods:HepG2 cells were treated with palmitic acid(PA)to model NAFLD in vitro.Lentivirus was used to regulate USP10 level in cells.Autophagic regulators were used to autophagic progression in cells.Western blotting,real-time fluorescence quantitative polymerase chain reaction,lipid drop staining and immunofluorescent staining were performed to determine the effect of USP10 on lipid autophagy.Student’s t-test and Tukey’s post hoc test were used to compare the means among groups.Results:PA induced cellular steatosis with dependance on autophagy.USP10 overexpression alleviated PA-induced steatosis,restored autophagic activity,promoted autophagic flux,including synthesis and degradation of autophagosomes,and lipid-targeted autophagy.In the presence of autophagy inhibitors,the protective effectiveness of USP10 on steatosis decreased.Furthermore,the specific inhibitor to C-jun N-terminal protein kinase-1(JNK1),DB07268,abolished USP10-induced autophagy.However,during early stage inhibition of JNK1,compensatory expression of tuberous sclerosis complex-2(TSC2)maintained autophagy.The degree of TSC2-to-JNK1 compensation was positively associated with USP10 level.Functionally,JNK1 and TSC2 were involved in the lipid-lowering effect of USP10.Conclusions:USP10 alleviated hepatocellular steatosis in autophagy-dependent manner.JNK1/TSC2 signaling pathways were required for USP10-induced autophagy.

Tu-Xian Decoction ameliorates diabetic cognitive impairment by inhibiting DAPK-1

Tu-Xian decoction(TXD),a traditional Chinese medicine(TCM)formula,has been frequently administered to manage diabetic cognitive impairment(DCI).Despite its widespread use,the mechanisms underlying TXD’s protective effects on DCI have yet to be fully elucidated.As a significant regulator in neurodegenerative conditions,death-associated protein kinase-1(DAPK-1)serves as a focus for understanding the action of TXD.This study was designed to whether TXD mediates its beneficial outcomes by inhibiting DAPK-1.To this end,a diabetic model was established using Sprague-Dawley(SD)rats through a high-fat,high-sugar(HFHS)diet regimen,followed by streptozotocin(STZ)injection.The experimental cohort was stratified into six groups:Control,Diabetic,TC-DAPK6,high-dose TXD,medium-dose TXD,and low-dose TXD groups.Following a 12-week treatment period,various assessments—including blood glucose levels,body weight measurements,Morris water maze(MWM)testing for cognitive function,brain magnetic resonance imaging(MRI),and histological analyses using hematoxylin-eosin(H&E),and Nissl staining—were conducted.Protein expression in the hippocampus was quantified through Western blotting analysis.The results revealed that TXD significantly improved spatial learning and memory abilities,and preserved hippocampal structure in diabetic rats.Importantly,TXD administration led to a down-regulation of proteins indicative of neurological damage and suppressed DAPK-1 activity within the hippocampal region.These results underscore TXD's potential in mitigating DCI via DAPK-1 inhibition,positioning it as a viable therapeutic candidate for addressing this condition.Further investigation into TXD's molecular mechanisms may elucidate new pathways for the treatment of DCI.