Genetic variation in GOLM1 and prefrontal cortical volume in Alzheimer's disease

Mapping rare protein-coding variants on multi-organ imaging traits

Human organ structure and function are important endophenotypes for clinical outcomes. Genome-wide association studies (GWAS) have identified numerous common variants associated with phenotypes derived from magnetic resonance imaging (MRI) of the brain and body. However, the role of rare protein-coding variations affecting organ size and function is largely unknown. Here we present an exome-wide association study that evaluates 596 multi-organ MRI traits across over 50,000 individuals from the UK Biobank. We identified 107 variant-level associations and 224 gene-based burden associations (67 unique gene-trait pairs) across all MRI modalities, including PTEN with total brain volume, TTN with regional peak circumferential strain in the heart left ventricle, and TNFRSF13B with spleen volume. The singleton burden model and AlphaMissense annotations contributed 8 unique gene-trait pairs including the association between an approved drug target gene of KCNA5 and brain functional activity. The identified rare coding signals elucidate some shared genetic regulation across organs, prioritize previously identified GWAS loci, and are enriched for drug targets. Overall, we demonstrate how rare variants enhance our understanding of genetic effects on human organ morphology and function and their connections to complex diseases.

Serum proteomic biomarker investigation of vascular depression using data-independent acquisition: a pilot study

Background

Vascular depression (VaD) is a depressive disorder closely associated with cerebrovascular disease and vascular risk factors. It remains underestimated owing to challenging diagnostics and limited information regarding the pathophysiological mechanisms of VaD. The purpose of this study was to analyze the proteomic signatures and identify the potential biomarkers with diagnostic significance in VaD.

Methods

Deep profiling of the serum proteome of 35 patients with VaD and 36 controls was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Functional enrichment analysis of the quantified proteins was based on Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and Reactome databases. Machine learning algorithms were used to screen candidate proteins and develop a protein-based model to effectively distinguish patients with VaD.

Results

There were 29 up-regulated and 31 down-regulated proteins in the VaD group compared to the controls (|log2FC| ≥ 0.26, p ≤ 0.05). Enrichment pathways analyses showed that neurobiological processes related to synaptic vesicle cycle and axon guidance may be dysregulated in VaD. Extrinsic component of synaptic vesicle membrane was the most enriched term in the cellular components (CC) terms. 19 candidate proteins were filtered for further modeling. A nomogram was developed with the combination of HECT domain E3 ubiquitin protein ligase 3 (HECTD3), Nidogen-2 (NID2), FTO alpha-ketoglutarate-dependent dioxygenase (FTO), Golgi membrane protein 1 (GOLM1), and N-acetylneuraminate lyase (NPL), which could be used to predict VaD risk with favorable efficacy.

Conclusion

This study offers a comprehensive and integrated view of serum proteomics and contributes to a valuable proteomics-based diagnostic model for VaD.

Comparative transcriptome analysis of the hippocampus from sleep-deprived and Alzheimer's disease mice

We did a comparative analysis of the gene expression profiles of the hippocampus from sleep deprivation and Alzheimer’s disease (AD) mice. Differentially expressed genes (DEGs) were identified by comparing the transcriptome profiles of the hippocampus of sleep deprivation or AD mouse models to matched controls. The common DEGs between sleep deprivation and AD were identified by the overlapping analysis, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The results showed that a total of 16 common DEGs showed similar change patterns in both sleep deprivation mice and AD mice. Sgk1, Ly6a, Atp6v0e, Hspb8, Htra1, Pdk4, Pfkfb3, Golm1, and Plin3 were up-regulated in the two disorders, whereas, Marcksl1, Fgd1, Scarb1, Mvd, Klhl13, Elovl2, and Vps29 were down-regulated. Acetyl-CoA metabolic process and lipid biosynthetic process were significantly enriched by those DEGs. The highly expressed DEGs and the two GO terms were associated with neuropathological changes according to the previous studies. As expected, sleep deprivation may contribute the AD development through these common DEGs.

H, Nadella RK, More RP, Seshadri M, Viswanath B, Rao M, Jain S, Mukherjee O. Exome sequencing in families with severe mental illness identifies novel and rare variants in genes implicated in Mendelian neuropsychiatric syndromes

AIM

Severe mental illnesses (SMI), such as bipolar disorder and schizophrenia, are highly heritable, and have a complex pattern of inheritance. Genome-wide association studies detect a part of the heritability, which can be attributed to common genetic variation. Examination of rare variants with next-generation sequencing may add to the understanding of the genetic architecture of SMI.

METHODS

We analyzed 32 ill subjects from eight multiplex families and 33 healthy individuals using whole-exome sequencing. Prioritized variants were selected by a three-step filtering process, which included: deleteriousness by five in silico algorithms; sharing within families by affected individuals; rarity in South Asian sample estimated using the Exome Aggregation Consortium data; and complete absence of these variants in control individuals from the same gene pool.

RESULTS

We identified 42 rare, non-synonymous deleterious variants (~5 per pedigree) in this study. None of the variants were shared across families, indicating a 'private' mutational profile. Twenty (47.6%) of the variant harboring genes were previously reported to contribute to the risk of diverse neuropsychiatric syndromes, nine (21.4%) of which were of Mendelian inheritance. These included genes carrying novel deleterious variants, such as the GRM1 gene implicated in spinocerebellar ataxia 44 and the NIPBL gene implicated in Cornelia de Lange syndrome.

CONCLUSION

Next-generation sequencing approaches in family-based studies are useful to identify novel and rare variants in genes for complex disorders like SMI. The findings of the study suggest a potential phenotypic burden of rare variants in Mendelian disease genes, indicating pleiotropic effects in the etiology of SMI.

GOLM1 promotes prostate cancer progression through activating PI3K-AKT-mTOR signaling

BACKGROUND

Prostate cancer (PCa) is the most commonly diagnosed cancer in men. Various molecular mechanisms account for PCa progression and elucidation of these mechanisms is key for selection of optimal therapies and improvement of patient outcome. Golgi membrane protein 1 (GOLM1) has been identified as a novel biomarker for PCa, but its biological functions and molecular mechanisms remain poorly understood.

METHOD

GOLM1 expression was determined in PCa by tissue microarrays (TMAs) and real-time RT-PCR, Western blot, and immunohistochemistry (IHC) analyses. To investigate GOLM1 functions in vitro and in vivo, we overexpressed and knocked down GOLM1 in PCa cell lines and established xenograft mice models. A series of cytological function assays were used to determine the role of GOLM1 in cell proliferation, migration, invasion, and apoptosis. PI3K-AKT-mTOR signaling pathway downstream of GOLM1 was detected by Western blot and IHC analyses.

RESULT

GOLM1 expression is up-regulated in PCa of all stages and grades. GOLM1 promotes proliferation, migration and invasion, and inhibits apoptosis in PCa cell lines (DU145, PC3, and CWR22Rv1) and xenograft mice models. Moreover, PI3K-AKT-mTOR signaling is positively regulated by GOLM1, whereas PI3 K inhibitor BKM120 significantly abrogates the oncogenic functions of GOLM1.

CONCLUSION

GOLM1 acts as a critical oncogene by promoting PCa cell proliferation, migration and invasion, and inhibiting apoptosis. GOLM1 plays oncogenic functions mainly through activating PI3K-AKT-mTOR signaling pathway. Therefore, agents that block PI3K-AKT-mTOR signaling pathway could be used in PCa patients with GOLM1 up-regulation.

Analyzing the genes related to Alzheimer's disease via a network and pathway-based approach

BACKGROUND

Our understanding of the molecular mechanisms underlying Alzheimer's disease (AD) remains incomplete. Previous studies have revealed that genetic factors provide a significant contribution to the pathogenesis and development of AD. In the past years, numerous genes implicated in this disease have been identified via genetic association studies on candidate genes or at the genome-wide level. However, in many cases, the roles of these genes and their interactions in AD are still unclear. A comprehensive and systematic analysis focusing on the biological function and interactions of these genes in the context of AD will therefore provide valuable insights to understand the molecular features of the disease.

METHOD

In this study, we collected genes potentially associated with AD by screening publications on genetic association studies deposited in PubMed. The major biological themes linked with these genes were then revealed by function and biochemical pathway enrichment analysis, and the relation between the pathways was explored by pathway crosstalk analysis. Furthermore, the network features of these AD-related genes were analyzed in the context of human interactome and an AD-specific network was inferred using the Steiner minimal tree algorithm.

RESULTS

We compiled 430 human genes reported to be associated with AD from 823 publications. Biological theme analysis indicated that the biological processes and biochemical pathways related to neurodevelopment, metabolism, cell growth and/or survival, and immunology were enriched in these genes. Pathway crosstalk analysis then revealed that the significantly enriched pathways could be grouped into three interlinked modules-neuronal and metabolic module, cell growth/survival and neuroendocrine pathway module, and immune response-related module-indicating an AD-specific immune-endocrine-neuronal regulatory network. Furthermore, an AD-specific protein network was inferred and novel genes potentially associated with AD were identified.

CONCLUSION

By means of network and pathway-based methodology, we explored the pathogenetic mechanism underlying AD at a systems biology level. Results from our work could provide valuable clues for understanding the molecular mechanism underlying AD. In addition, the framework proposed in this study could be used to investigate the pathological molecular network and genes relevant to other complex diseases or phenotypes.

GP73 is upregulated by hepatitis C virus (HCV) infection and enhances HCV secretion

Hepatitis C virus (HCV) is a major cause of chronic liver disease. However, little is known about the details of its assembly and secretion. Golgi-related proteins have been recently proven to have a key function in HCV secretion. Golgi protein 73 (GP73), a resident Golgi membrane protein, is a potential serum biomarker for the diagnosis of liver diseases and hepatocellular carcinoma. Previous studies have demonstrated the upregulation of GP73 in the liver samples and sera of HCV-infected patients. However, the function and regulatory mechanism of GP73 in HCV infection at the cellular level remain unknown. In this study, we examined the expression level of GP73 in HCV infected cells and its effect on HCV life cycle in cell culture systems. Both the protein expression and mRNA levels of GP73 significantly increased in HCV subgenomic replicon-harboring cells and HCV-infected cells, which imply that GP73 was upregulated by HCV infection. HCV production was significantly enhanced when GP73 was overexpressed, but dramatically inhibited when GP73 was silenced. However, the overexpression and knockdown of GP73 showed no evident effect on the entry, protein translation, RNA replication, and assembly of HCV, which indicates that GP73 enhanced the secretion process. Moreover, the coiled-coil domain of GP73 was required to increase HCV secretion. GP73 increased and interacted with apolipoprotein E, an identified host factor that assists in HCV secretion. These results demonstrate the critical function of GP73 in HCV secretion and provide new insights into the therapeutic design of antiviral strategies.

Association studies of 19 candidate SNPs with sporadic Alzheimer's disease in the North Chinese Han population

Genome-wide association studies (GWAS) identified multiple single-nucleotide polymorphisms (SNPs) that are associated with the pathogenesis of Alzheimer's disease (AD). As replication in independent studies remains the only way to validate proposed GWAS signals, we detect SNPs reported in the GWAS, in order to explore their association with sporadic AD (SAD) in the Chinese population. We analyzed genotype and allele distributions of 19 SNPs reported in GWAS in 191 SAD patients and 180 healthy controls. We found that higher frequencies of rs10868366 G and rs7019241 C carriers were observed in SAD patients compared with controls (rs10868366 G: P = 0.026, odds ratio (OR) = 1.4, 95% confidence intervals (CI) 1.0-1.9; rs7019241 C: P = 0.019, OR 1.4, 95% CI 1.6-1.9). Furthermore, rs10868366 G/T and rs7019241 C/T in GOLPH2 were in strong linkage disequilibrium and formed a relative protective factor rs10868366 T/rs7019241 T and a relative risk factor rs10868366 G/rs7019241 C. For SNP rs3826656 in near gene 5' region of CD33, the results revealed that in subjects with APOE ε4 alleles, the A allele was associated with a reduced risk of SAD compared with the G allele (OR 0.479; 95% CI 0.263-0.870, P = 0.015), and AA genotype was associated with a reduced risk of SAD compared with the genotype AG + GG (OR 0.395; 95% CI 0.158-0.659, P = 0.008). Our results support the view that rs10868366 and rs7019241 in GOLPH2 and rs3826656 in near gene 5' region of CD33 are significantly associated with SAD in the north Chinese Han population.