Project description:Characterization of ancestry-linked peptide variants in disease-relevant patient tissues represents a foundational step to connect patient ancestry with molecular disease pathogenesis. Nonsynonymous single nucleotide polymorphisms (SNPs) encoding missense substitutions within tryptic peptides exhibiting high allele frequencies in European, African, and East Asian populations, termed peptide ancestry informative markers (pAIMs), were prioritized from 1000 genomes. In silico analysis shows that as few as 20 pAIMs can determine ancestry proportions similarly to >260K SNPs (R2=0.9905). Multiplexed proteomic analysis of >100 human endometrial cancer cell lines and uterine leiomyoma (ULM) tissues combined resulted in the quantitation of 62 pAIMs that correlate with self-described race and genotype-confirmed patient ancestry. Candidates include a D451E substitution in GC vitamin D-binding protein previously associated with altered vitamin D levels in African and European populations. These efforts describe a generalized set of markers for proteoancestry assessment that will further support studies investigating the impact of ancestry on the human proteome and how this relates to the pathogenesis of uterine neoplasms.
Project description:Variation in gene expression is a fundamental aspect of human phenotypic variation. Several studies have analyzed gene expression levels in populations of different continental ancestry, and concluded that there is variation across populations at a fraction of expressed genes. Here we analyze gene expression levels in African American cell lines, which differ from previously analyzed cell lines in that samples from this population have variable proportions of continental ancestry. We show that for most genes examined, gene expression varies with genetic ancestry. Experiment Overall Design: Lymphoblastoid cell lines (LCL) for 60 HapMap CEU, 60 HapMap YRI, and 82 AFA from the Human Variation Panel were obtained from Coriell Cell Repositories. LCLs were grown in culture, total RNA was extracted and hybridized to Affymetrix HG-FOCUS arrays.
Project description:Women of sub-Saharan African descent have disproportionately higher incidence of Triple Negative Breast Cancer (TNBC), and TNBC-specific mortality. Population comparative studies show racial differences in TNBC biology, including higher prevalence of basal-like and Quadruple-Negative subtypes in African Americans (AA). However, previous investigations relied on self-reported race (SRR) of primarily United States (US) populations. Due to heterogenous genetic admixture, and biological consequences of social determinants, the true association of African ancestry with TNBC biology is unclear. To address this, we conducted RNAseq on an international cohort of AAs, west and east Africans with TNBC. Using comprehensive genetic ancestry estimation in this African-enriched cohort, we found expression of 613 genes associated with African ancestry and 2000+ associated with regional African ancestry. A subset of African-associated genes also showed differences in normal breast tissue. Pathway enrichment and deconvolution of tumor cellular composition revealed tumor-associated immunological profiles are distinct in patients of African descent.
Project description:Background: Genetic control of gene expression in asthma-related tissues is not well-characterized, particularly for African-ancestry populations, limiting advancement in our understanding of the increased prevalence and severity of asthma in those populations. Objective: To create novel transcriptome prediction models for asthma tissues (nasal epithelium and CD4+ T cells) and apply them in transcriptome-wide association study to discover candidate asthma genes. Methods: We developed and validated gene expression prediction databases for unstimulated CD4+ T cells and nasal epithelium using an elastic net framework. Combining these with existing prediction databases (N=51), we performed TWAS of 9,284 individuals of African-ancestry to identify tissue-specific and cross-tissue candidate genes for asthma. Results: Novel databases for CD4+ T cells and nasal epithelial gene expression prediction contain 8,351 and 10,296 genes, respectively, including four asthma loci (SCGB1A1, MUC5AC, ZNF366, LTC4S) not predictable with existing public databases. Prediction performance was comparable to existing databases and was most accurate for populations sharing ancestry with the training set (e.g. African ancestry). From transcriptome-wide association study, we identified 17 candidate causal asthma genes (adjusted P<0.1), including genes with tissue-specific (IL33 in nasal epithelium) and cross-tissue (CCNC and FBXW7) effects. Conclusions: Expression of IL33, CCNC, and FBXW7 may affect asthma risk in African ancestry populations by mediating inflammatory responses. The addition of CD4+ T cell and nasal epithelium prediction databases to the public sphere will improve ancestry representation and power to detect novel gene-trait associations from transcriptome-wide association study.
Project description:Study of genes that are differentially spliced and differentially expressed between African Americans and whites with lung squamous cell cancer. Despite racial disparities in lung cancer, the molecular landscape of lung cancer in patients of African ancestry remains underexplored. Population-related differences in alternative RNA splicing have not been explored. We identified differentially spliced genes and differentially expressed genes between lung squamous cell carcinoma from patients of West African and European ancestry.
Project description:Variation in gene expression is a fundamental aspect of human phenotypic variation. Several studies have analyzed gene expression levels in populations of different continental ancestry, and concluded that there is variation across populations at a fraction of expressed genes. Here we analyze gene expression levels in African American cell lines, which differ from previously analyzed cell lines in that samples from this population have variable proportions of continental ancestry. We show that for most genes examined, gene expression varies with genetic ancestry. Keywords: Human Gene Expression Study
Project description:Differences in microRNAs have not been well studied as potential mechanisms underlying the breast cancer disparity. A number of miRNAs were differentially expressed not only by tumor subtype but by ancestry, indicating differences in tumor biology of breast cancer between women of African and European ancestry. Findings may contribute to a better understanding of the biology of breast cancer disparities and help develop more targeted preventative and therapeutic strategies.
2018-12-06 | GSE117452 | GEO
Project description:LCL RNA-seq from African Ancestry Samples in the 1000 Genomes Project