Browsing by Author "Sood, Ajit"

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Celiac disease-associated loci show considerable genetic overlap with neuropsychiatric diseases but with limited transethnic applicability
(Springer, 2023-01-10T00:00:00) Sharma, Nidhi; Banerjee, Pratibha; Sood, Ajit; Midha, Vandana; Thelma, B.K.; Senapati, Sabyasachi
Clinical and public health research has revealed the co-occurrence of several neuropsychiatric diseases among patients with celiac disease (CD). The significant presence of CD-specific autoantibodies in patients with neuropsychiatric diseases and vice versa are often reported. To explain the genetic basis of such frequent disease co-occurrence and investigate the underlying common pathways/processes, we performed an extensive cross-disease association study followed by supporting in silico functional validation of the leads. Genomewide association study (GWAS) data for CD and eight commonly co-occurring neuropsychiatric diseases from Caucasian populations were analysed, and the shared loci were determined. We performed Immunochip-based fine mapping of these overlapping association signals in an independent European CD data and tested their cross-ethnic transferability using CD association data from the genetically distinct north Indian population. This study identified 12 shared loci between the two diseases with genomewide significance (P ? 5e-8). Of these five loci, namely NFIA, KIA1109, NOTCH4-TSBP1-PBX2, HLA-DQA1 and CSK replicated in an independent Dutch cohort representing European ancestry. Three of these loci, namely NFIA, NOTCH4-TSBP1-PBX2 and HLA-DQA1 that are common between CD, anxiety, migraine and schizophrenia respectively withstood locus transferability test in north Indians. Tissue-specific eQTL analysis of SNPs from transferable loci revealed expression QTL effects in brain tissue besides the small intestine and whole blood. Pathway analysis and evidence of epigenetic regulation highlighted the potential contribution of these SNPs to disease pathology. The replicable and transferable association of genetic variants from MHC locus and their functional implications suggest the process of antigen presentation and adaptive/innate immune response regulated by non-HLA genes in the locus may dominate the shared pathogenesis of CD and neuropsychiatric diseases. Functional validation of the shared candidate genes is warranted to unravel the molecular mechanism for the co-occurrence of CD and specific neuropsychiatric diseases. � 2023, Indian Academy of Sciences.
A duodenal mucosa transcriptome study identified reduced expression of a novel gene CDH18 in celiac disease
(Elsevier B.V., 2023-10-09T00:00:00) Banerjee, Pratibha; Sood, Ajit; Midha, Vandhana; Narang, Vikram; Grover, Jasmine; Senapati, Sabyasachi
Background: Celiac disease (CD) a complex immune disease that affects duodenal mucosa. Identification of tissue specific biomarkers is expected to improve the existing biopsy based CD diagnosis. Aims: To investigate the differentially expressed genes (DEGs) in duodenal mucosa tissue to identify clinically relevant gene expression pattern in CD. Methods: Whole RNA extracted from the duodenal biopsies of three CD patients and four non-CD controls were sequenced. Significant DEGs were identified. Prioritized DEGs were validated using qRT-PCR in an independent group (CD=23; Control=26). Enriched pathways were analyzed, protein-protein interaction networks were evaluated. Results: 923 DEGs comprising of 135 up-regulated, and 788 down-regulated genes, with p-value?0.05; log2FC>2 or <-2 were identified. A novel down-regulated gene CDH18 (p = 0.03; log2FC=?0.74) was identified. Previously known CXCL9 was replicated. CDH18, a trans-membrane protein was found to interact with other CDH proteins, ?/? catenins, and other membrane transporters such as SLC and ABCB. Pathways and protein networks contributing in channel activity (p = 2.15E-12), membrane transporters (p = 2.15E-12), and cellular adhesion (p = 8.05E-6) were identified. Conclusions: CDH18, a novel DEG identified in the present study is a pivotal gene involved in maintaining epithelial membrane organization and integrity. The functional significance of lower expression of CDH18 in pathogenesis of CD warranted to be investigated. CDH18 expression could be tested for its effectiveness in diagnostic, prognostic and therapeutic purposes. � 2023 Editrice Gastroenterologica Italiana S.r.l.
Multiple allelic associations from genes involved in energy metabolism were identified in celiac disease
(Springer, 2021-06-23T00:00:00) Bhagavatula, Sandilya; Banerjee, Pratibha; Sood, Ajit; Midha, Vandana; Thelma, B.K.; Senapati, Sabyasachi
Energy metabolism is a critical factor that influences disease pathogenesis. Recent high-throughput genomic studies have enabled us to look into disease biology with greater details. Celiac disease (CD) is an inflammatory autoimmune disease where ~60 non-HLA genes were identified which in conjunction with HLA genes explain ~55% of the disease heritability. In this study we aimed to identify susceptibility energy metabolism genes and investigate their role in CD. We re-analysed published Immunochip genotyping data, which were originally analysed for CD association studies in north Indian and Dutch population. 269 energy metabolism genes were tested. Meta-analysis was done for the identified SNPs. To validate the functional implications of identified markers and/or genes, in silico functional annotation was performed. Six SNPs were identified in north Indians, of which three markers from two loci were replicated in Dutch. rs2071592 (PMeta=5.01e?75) and rs2251824 (PMeta=1.87e?14) from ATP6V1G2-NFKBIL1-DDX39B locus and rs4947331 (PMeta= 9.85e?13) from NEU1 locus were found significantly associated. Identified genes are key regulators of cellular energy metabolism and associated with several immune mediated diseases. In silico functional annotation showed significant biological relevance of these novel markers and genes. FDI approved therapeutics against ATP6V1G2 and NEU1 are currently in use to treat chronic and inflammatory diseases. This study identified two pathogenic loci, originally involved in energy metabolism. Extensive investigation showed their synergistic role in CD pathogenesis by promoting immune mediated enteric inflammation. Proposed CD pathogenesis model in this study needs to be tested through tissue-on-chip and in vivo methods to ensure its translational application. � 2021, Indian Academy of Sciences.