Wanhong Liu

Association of corticotropin-releasing hormone receptor1 gene SNP and haplotype with major depression

The dysregulation of the activity of the hypothalamic-pituitary-adrenocortical (HPA) axis system is one of the major neuroendocrine abnormalities in major depression (MD). Many pieces of evidence supported that corticotropin-releasing hormone (CRH) play a role in the pathophysiology of major depression. In this article, whether genetic variations in the corticotropin-releasing hormone receptor1 (CRHR1) gene might be associated with increased susceptibility to major depression was studied by using a gene-based association analysis of single-nucleotide polymorphisms (SNPs). Three SNPs were identified in CRHR1 gene and genotyped in the samples of patients diagnosed with major depression and matched controls. We observed significant allele (P=0.0008) and genotype (P=0.0002) association with rs242939, and the haplotype defined by alleles G-G-T for the represent rs1876828, rs242939 and rs242941 was significantly over-represented in major depression patients compared to controls. These results support the idea that the CRHR1 gene is likely to be involved in the genetic vulnerability for major depression.

Association study of corticotropin-releasing hormone receptor1 gene polymorphisms and antidepressant response in major depressive disorders.

Hypothalamic-pituitary-adrenal (HPA) axis appears to play a key role in the pathogenesis of major depressive disorders (MDD). Treatment of certain selective serotonin reuptake inhibitors (SSRIs) has been shown to reduce the activity of corticotropin-releasing hormone (CRH) neurons and may contribute to their therapeutic action. It has been proposed that the downregulation of CRH activity is final and common step of antidepressant treatment. In this study, we tested whether the polymorphisms of three sites (rs1876828, rs242939 and rs242941) in corticotropin-releasing hormone receptor1 (CRHR1) gene are related to 6 weeks fluoxetine antidepressant effect in 127 Han Chinese patients with MDD. The results show that the rs242941 G/G genotype and homozygous GAG haplotype of the three single-nucleotide polymorphisms (SNPs) are associated with fluoxetine therapeutic response in MDD patients of high-anxiety (HA). The results support the idea that the CRHR1 gene is likely to be involved in the antidepressant response in MDD.

DLP1-Dependent Mitochondrial Fragmentation Mediates 1-methyl-4-phenylpyridinium Toxicity in Neurons: Implications for Parkinson's Disease

Selective degeneration of nigrostriatal dopaminergic neurons in Parkinson’s disease (PD) can be modeled by the administration of the neurotoxin 1‐methyl‐4‐phenylpyridinium (MPP+). Because abnormal mitochondrial dynamics are increasingly implicated in the pathogenesis of PD, in this study, we investigated the effect of MPP+ on mitochondrial dynamics and assessed temporal and causal relationship with other toxic effects induced by MPP+ in neuronal cells. In SH‐SY5Y cells, MPP+ causes a rapid increase in mitochondrial fragmentation followed by a second wave of increase in mitochondrial fragmentation, along with increased DLP1 expression and mitochondrial translocation. Genetic inactivation of DLP1 completely blocks MPP+‐induced mitochondrial fragmentation. Notably, this approach partially rescues MPP+‐induced decline in ATP levels and ATP/ADP ratio and increased [Ca2+]i and almost completely prevents increased reactive oxygen species production, loss of mitochondrial membrane potential, enhanced autophagy and cell death, suggesting that mitochondria fragmentation is an upstream event that mediates MPP+‐induced toxicity. On the other hand, thiol antioxidant N‐acetylcysteine or glutamate receptor antagonist D‐AP5 also partially alleviates MPP+‐induced mitochondrial fragmentation, suggesting a vicious spiral of events contributes to MPP+‐induced toxicity. We further validated our findings in primary rat midbrain dopaminergic neurons that 0.5 μm MPP+ induced mitochondrial fragmentation only in tyrosine hydroxylase (TH)‐positive dopaminergic neurons in a similar pattern to that in SH‐SY5Y cells but had no effects on these mitochondrial parameters in TH‐negative neurons. Overall, these findings suggest that DLP1‐dependent mitochondrial fragmentation plays a crucial role in mediating MPP+‐induced mitochondria abnormalities and cellular dysfunction and may represent a novel therapeutic target for PD.

A novel human foamy virus mediated gene transfer of GAD67 reduces neuropathic pain following spinal cord injury.

Neuropathic pain is a long-lasting clinical problem that is often refractory to medical management. Gene transfer of specific genes for therapeutic benefit offers a novel approach to the treatment of neuropathic pain. In this study, we tested whether the transfer of the glutamic acid decarboxylase (GAD) gene to dorsal root ganglion (DRG) cells would attenuate below-injury level central neuropathic pain after spinal cord injury (SCI) by using a novel human foamy virus (HFV) vector to achieve release of gamma-aminobutyric acid (GABA). Subcutaneous inoculation of a replication-defective HFV vector, which expresses GAD (vector rdvGAD67) for 7days after T13 spinal cord hemisection, reversed mechanical allodynia and thermal hyperalgesia evoked by SCI. The antiallodynic effect lasted 6 weeks and was reestablished by reinoculation. We also found that subcutaneous inoculation of rdvGAD67 resulted in enhanced production of GAD and tonical GABA release from transduced DRG neurons. These results suggest that HFV-mediated gene transfer to DRG could be employed to treat below-injury level central neuropathic pain after incomplete SCI.

Selective inhibition of CCR7(-) effector memory T cell activation by a novel peptide targeting Kv1.3 channel in a rat experimental autoimmune encephalomyelitis model.

Background: The effect of ADWX-1 on EAE model is unknown. Results: ADWX-1 selectively inhibits TEM activation through regulating both Kv1.3 activity and expression. Conclusion: ADWX-1 ameliorates EAE with a cell selectivity mechanism. Significance: ADWX-1 is a novel potent candidate therapeutic drug for MS. The voltage-gated Kv1.3 K+ channel in effector memory T cells serves as a new therapeutic target for multiple sclerosis. In our previous studies, the novel peptide ADWX-1 was designed and synthesized as a specific Kv1.3 blocker. However, it is unclear if and how ADWX-1 alleviates experimental autoimmune encephalomyelitis, a model for multiple sclerosis. In this study, the administration of ADWX-1 significantly ameliorated the rat experimental autoimmune encephalomyelitis model by selectively inhibiting CD4+CCR7− phenotype effector memory T cell activation. In contrast, the Kv1.3-specific peptide had little effect on CD4+CCR7+ cells, thereby limiting side effects. Furthermore, we determined that ADWX-1 is involved in the regulation of NF-κB signaling through upstream protein kinase C-θ (PKCθ) in the IL-2 pathway of CD4+CCR7− cells. The elevated expression of Kv1.3 mRNA and protein in activated CD4+CCR7− cells was reduced by ADWX-1 engagement; however, an apparent alteration in CD4+CCR7+ cells was not observed. Moreover, the selective regulation of the Kv1.3 channel gene expression pattern by ADWX-1 provided a further and sustained inhibition of the CD4+CCR7− phenotype, which depends on the activity of Kv1.3 to modulate its activation signal. In addition, ADWX-1 mediated the activation of differentiated Th17 cells through the CCR7− phenotype. The efficacy of ADWX-1 is supported by multiple functions, which are based on a Kv1.3high CD4+CCR7− T cell selectivity through two different pathways, including the classic channel activity-associated IL-2 pathway and the new Kv1.3 channel gene expression pathway.

A novel finding for enterovirus virulence from the capsid protein VP1 of EV71 circulating in mainland China

Enterovirus 71 (EV71) is a neurotropic virus that causes various clinical manifestations in young children, ranging from asymptomatic to fatal. Different pathotypes of EV71 notably differ in virulence. Several virulence determinants of EV71 have been predicted. However, these reported virulence determinants could not be used to identify the EV71 strains of subgenotype C4, which mainly circulate in China. In this study, VP1 sequences of 37 EV71 strains from severe cases (SC-EV71) and 192 EV71 strains from mild cases (MC-EV71) in mainland China were analyzed to determine the potential virulence determinants in the capsid protein VP1 of EV71. Although most SC-EV71 strains belonged to subgenotype C4a, no specific genetic lineages in C4a were correlated with EV71 virulence. Interestingly, amino acid substitutions at nine positions (H22Q, P27S, N31S/D, E98K, E145G/Q, D164E, T240A/S, V249I, and A289T) were detected by aligning the VP1 sequences of the SC-EV71 and MC-EV71 strains. Moreover, both the constituent ratios of the conservative or mutated residues in the MC-EV71 and SC-EV71 strains and the changes in the VP1 3D structure resulting from these mutations confirmed that the conservative residues (22H, 249V, and 289A) and the mutated residues (27S, 31S/D, 98K, 145G/Q, 164E, and 240A/S) might be potential virulence determinants in VP1 of EV71. Furthermore, these results led to the hypothesis that VP1 acts as a sandwich switch for viral particle stabilization and cellular receptors attachment, and specific mutations in this protein can convert mild cases into severe cases. These findings highlight new opportunities for diagnostic and therapeutic interventions.

MicroRNA-503 acts as a tumor suppressor in glioblastoma for multiple antitumor effects by targeting IGF-1R

microRNA (miRNA) dysregulation is associated with various types of human cancer by regulating cancer cell survival, proliferation and invasion. Aberrant expression of microRNA-503 (miR-503) has been reported in several cancer profiles. However, potential linkage of miR-503 levels and the underlying regulatory mechanisms in human glioblastoma multiforme (GBM) remain unclear. In the present study, we showed for the first time that the expression of miR-503 was significantly reduced in GBM tissues and cell lines (U251 and U87MG) relative to normal brain tissues. Furthermore, our results demonstrated that overexpression of miR-503 in GBM cell lines not only suppressed cell proliferation through inducing G0/G1 cell cycle arrest and apoptosis, but also inhibited cancer cell migration and tumor invasion. In addition, we identified insulin-like growth factor-1 (IGF-1R) receptor mRNA is a bona fide target of miR-503 by computational analysis followed by luciferase reporter assays. Of note, upregulation of miR-503 in GBM cells suppressed endogenous IGF-1R protein expression. Further mechanistic analysis revealed that forced expression of miR-503 inhibited AKT activation, suggesting the tumor suppressive effect of miR-503 in GBM cells is partially mediated by phosphatidylinositol 3-kinase/AKT signaling. Taken together, the results of the present study demonstrated that miR-503 is a tumor suppressor for GBM and a favorable factor against glioma progression through targeting IGF-1R, thus providing a new evidence-supported prognostic marker for GBM diagnosis.

Interaction between CRHR1 and BDNF Genes Increases the Risk of Recurrent Major Depressive Disorder in Chinese Population

Background An important etiological hypothesis about depression is stress has neurotoxic effects that damage the hippocampal cells. Corticotropin-releasing hormone (CRH) regulates brain-derived neurotrophic factor (BDNF) expression through influencing cAMP and Ca2+ signaling pathways during the course. The aim of this study is to examine the single and combined effects of CRH receptor 1 (CRHR1) and BDNF genes in recurrent major depressive disorder (MDD). Methodology/Principal Finding The sample consists of 181 patients with recurrent MDD and 186 healthy controls. Whether genetic variations interaction between CRHR1 and BDNF genes might be associated with increased susceptibility to recurrent MDD was studied by using a gene-based association analysis of single-nucleotide polymorphisms (SNPs). CRHR1 gene (rs1876828, rs242939 and rs242941) and BDNF gene (rs6265) were identified in the samples of patients diagnosed with recurrent MDD and matched controls. Allelic association between CRHR1 rs242939 and recurrent MDD was found in our sample (allelic: p = 0.018, genotypic: p = 0.022) with an Odds Ratio 0.454 (95% CI 0.266–0.775). A global test of these four haplotypes showed a significant difference between recurrent MDD group and control group (chi-2 = 13.117, df = 3, P = 0.016. Furthermore, BDNF and CRHR1 interactions were found in the significant 2-locus, gene–gene interaction models (p = 0.05) using a generalized multifactor dimensionality reduction (GMDR) method. Conclusion Our results suggest that an interaction between CRHR1 and BDNF genes constitutes susceptibility to recurrent MDD.

MiR-129 triggers autophagic flux by regulating a novel Notch-1/ E2F7/Beclin-1 axis to impair the viability of human malignant glioma cells.

Abnormalities of autophagy have been implicated in an increasing number of human cancers, including glioma. To date, there is a wealth of evidence indicating that microRNAs (miRNAs) contribute significantly to autophagy in a variety of cancers. Previous studies have suggested that miR-129 functioned as an important inhibitor of the cell cycle and could promote the apoptosis of many cancer cell lines in vitro. Here, we reported that miR-129 acted as a potent inducer of autophagy. Forced expression of miR-129 could induce autophagic flux by targetedly suppressing Notch-1 in glioma cells. The autophagy induced by miR-129 could restrain the activity of mammalian target of rapamycin (mTOR) and upregulate Beclin-1. Moreover, we demonstrated that E2F transcription factor 7 (E2F7) could also trigger autophagic flux by upregulating Beclin-1 and mediating miR-129-induced autophagy. Additionally, knockdown of Notch-1 could upregulate the expression of E2F7, whereas downregulation of E2F7 alleviated shNotch-1-induced autophagic flux. In particular, knockdown of endogenous Beclin-1 could effectively reduce autophagic flux stimulated by miR-129 and E2F7. Interestingly, upon attenuation of miR-129- or E2F7-triggered autophagic flux rescued cell viability suppressed by them. More importantly, intratumoral injection of pHAGE-miR-129 lentivirus in a nude mouse xenograft model significantly restrained tumor growth and triggered autophagy. In conclusion, these findings identify a new function for miR-129 as a potent inducer of autophagy through a novel Notch-1/E2F7/Beclin-1 axis in glioma.

Coxsackievirus A16 elicits incomplete autophagy involving the mTOR and ERK pathways.

Autophagy is an important homeostatic process for the degradation of cytosolic proteins and organelles and has been reported to play an important role in cellular responses to pathogens and virus replication. However, the role of autophagy in Coxsackievirus A16 (CA16) infection and pathogenesis remains unknown. Here, we demonstrated that CA16 infection enhanced autophagosome formation, resulting in increased extracellular virus production. Moreover, expression of CA16 nonstructural proteins 2C and 3C was sufficient to trigger autophagosome accumulation by blocking the fusion of autophagosomes with lysosomes. Interestingly, we found that Immunity-related GTPase family M (IRGM) was crucial for the activation of CA16 infection-induced autophagy; in turn, reducing IRGM expression suppressed autophagy. Expression of viral protein 2C enhanced IRGM promoter activation, thereby increasing IRGM expression and inducing autophagy. CA16 infection inhibited Akt/mTOR signaling and activated extracellular signal-regulated kinase (ERK) signaling, both of which are necessary for autophagy induction. In summary, CA16 can use autophagy to enhance its own replication. These results raise the possibility of targeting the autophagic pathway for the treatment of hand, foot, and mouth disease (HFMD).