Project description:(1) In clinical practice and biomedical research populations are often divided categorically into distinct racial and ethnic groups. In reality, these categories comprise diverse groups with highly heterogeneous histories, cultures, traditions, religions, as well as social and environmental exposures. While the factors captured by these categories contribute to clinical practice and biomedical research, the use of race/ethnicity is widely debated. As a response to this debate, genetic ancestry has been suggested as a complement or alternative to this categorization. However, few studies have examined the effect of genetic ancestry, racial/ethnic identity, and environmental exposures on biological processes. Herein, we examine the contribution of self-identification within ethnicity, genetic ancestry, and environmental exposures on epigenetic modification of DNA methylation, a phenomenon affected by both genetic and environmental factors. We typed over 450,000 variably methylated CpG sites in primary whole blood of 573 individuals of Mexican and Puerto Rican descent who also had high-density genotype data. We found that methylation levels at a large number of CpG sites were significantly associated with ethnicity even when adjusting for genetic ancestry. In addition, we found an enrichment of ethnicity-associated sites amongst loci previously associated with environmental and social exposures. Interestingly, one of the strongest associated sites is driven by the Duffy Null blood type variant, demonstrating a new function of the locus in lymphocytes. Overall, the methylation changes associated with race/ethnicity, driven by both genes and environment, highlight the importance of measuring and accounting for both self-identified race/ethnicity and genetic ancestry in clinical and biomedical studies and the benefits of studying diverse populations. (2) In epigenome-wide association studies (EWAS), different methylation profiles of distinct cell-types may lead to false discoveries. We introduce ReFACTor, a method based on principal component analysis (PCA) for the correction of cell-type heterogeneity in EWAS. ReFACTor does not require knowledge of the cell counts, and it obtains improved estimates of the cell-type composition, resulting in improved power and control for false positives in EWAS. Bisulphite converted DNA from 573 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip and a complete blood count with automated white blood cell differential was performed by automated flow cytometry for 95 of the samples.
Project description:This research trial studies how well biospecimen collection works in identifying genetic changes in patients with breast, prostate, colorectal, liver, or kidney cancer or multiple myeloma undergoing surgery. Studying samples collected during surgery may add to the understanding of cancer by looking for the genetic changes that cause early cancer onset in people of certain racial and ethnic groups.
Project description:In the US, the majority of cancer samples analyzed are from white people, leading to biases in racial and ethnic treatment outcomes. Colorectal cancer (CRC) incidence and mortality rates are high in Alabama African Americans (AAs) and Oklahoma American Indians (AIs). We hypothesized that differences between racial groups may partially explain these disparities. Thus, we compared transcriptomic profiles of CRCs of Alabama AAs, Oklahoma AIs, and white people from both states. Compared to CRCs of white people, CRCs of AAs showed (a) higher expression of cytokines and vesicle trafficking toward modulated antitumor-immune activity, and (b) lower expression of the ID1/BMP/SMAD axis, IL22RA1, APOBEC3, and Mucins; and AIs had (c) higher expression of PTGS2/COX2 (an NSAID target/pro-oncogenic inflammation) and splicing regulators, and (d) lower tumor suppressor activities (e.g., TOB2, PCGF2, BAP1). Therefore, targeting strategies designed for white CRC patients may be less effective for AAs/AIs. These findings illustrate needs to develop optimized interventions to overcome racial CRC disparities.
Project description:(1) In clinical practice and biomedical research populations are often divided categorically into distinct racial and ethnic groups. In reality, these categories comprise diverse groups with highly heterogeneous histories, cultures, traditions, religions, as well as social and environmental exposures. While the factors captured by these categories contribute to clinical practice and biomedical research, the use of race/ethnicity is widely debated. As a response to this debate, genetic ancestry has been suggested as a complement or alternative to this categorization. However, few studies have examined the effect of genetic ancestry, racial/ethnic identity, and environmental exposures on biological processes. Herein, we examine the contribution of self-identification within ethnicity, genetic ancestry, and environmental exposures on epigenetic modification of DNA methylation, a phenomenon affected by both genetic and environmental factors. We typed over 450,000 variably methylated CpG sites in primary whole blood of 573 individuals of Mexican and Puerto Rican descent who also had high-density genotype data. We found that methylation levels at a large number of CpG sites were significantly associated with ethnicity even when adjusting for genetic ancestry. In addition, we found an enrichment of ethnicity-associated sites amongst loci previously associated with environmental and social exposures. Interestingly, one of the strongest associated sites is driven by the Duffy Null blood type variant, demonstrating a new function of the locus in lymphocytes. Overall, the methylation changes associated with race/ethnicity, driven by both genes and environment, highlight the importance of measuring and accounting for both self-identified race/ethnicity and genetic ancestry in clinical and biomedical studies and the benefits of studying diverse populations. (2) In epigenome-wide association studies (EWAS), different methylation profiles of distinct cell-types may lead to false discoveries. We introduce ReFACTor, a method based on principal component analysis (PCA) for the correction of cell-type heterogeneity in EWAS. ReFACTor does not require knowledge of the cell counts, and it obtains improved estimates of the cell-type composition, resulting in improved power and control for false positives in EWAS.
Project description:African Americans (AA) are 70% more likely than Caucasian Americans (CA) to die from heart failure (HF) even after adjusting for known causes. Although the causal factors responsible for this racial disparity remain unknown, it is theorized that environmental stressors This alarming health disparity represents an important challenge to U.S. healthcare as global prevalence of heart failure has already exceeded epidemic levels with a disease burden that disproportionately impacts members of ethnic and racial minorities. The current multicohort study of cardiac DNA methylation identifies the cardiac epigenome as a previously unrecognized syntax that encodes race-based environmental differences in the failing human heart.
Project description:African Americans (AA) are 70% more likely than Caucasian Americans (CA) to die from heart failure (HF) even after adjusting for known causes. Although the causal factors responsible for this racial disparity remain unknown, it is theorized that environmental stressors This alarming health disparity represents an important challenge to U.S. healthcare as global prevalence of heart failure has already exceeded epidemic levels with a disease burden that disproportionately impacts members of ethnic and racial minorities. The current multicohort study of cardiac DNA methylation identifies the cardiac epigenome as a previously unrecognized syntax that encodes race-based environmental differences in the failing human heart.
Project description:There is extensive variation in DNA methylation between individuals and ethnic groups. These differences can arise from a combination of genetic and non-genetic influences and potential modifiers include nutritional cues, early life experience, and social and physical environments. Here we have assayed genome-wide DNA methylation in neonatal cord blood from African American, European American, and other ancestral groups. This is part of the CANDLE Study (Conditions Affecting Neurocognitive Development and Learning in Early Childhood). Our overarching goal is to determine the different environmental and maternal factors that can modify DNA methylation in newborns. This is a cross-sectional study of a total of 216 racially diverse participants of CANDLE. Cordblood was collected at birth. DNA methylation was measured using the Illumina HumanMethylation27 BeadChip. Based on maternal self-report, the samples are 112 African Americans, 91 European Americans and 13 other racial or mixed race group.
Project description:Animals possess inborn ability to recognize certain odors to avoid predators, seek food and find mates. Innate odor preference has been thought to be genetically hardwired. Here we report that acquisition of innate odor recognition requires spontaneous neural activity and is influenced by sensory experience during early postnatal development. Genetic silencing of mouse olfactory sensory neurons during the critical period has little impact on odor sensitivity, discrimination and recognition later in life. However, it abolishes innate odor preference and alters the patterns of activation in brain centers. Moreover, exposure to an aversive odor during the critical period abolishes aversion in adulthood in an odor specific manner. The loss of innate aversion is associated with broadened projection of OSNs. Thus, a delicate balance of neural activity is required during critical period in establishing innate odor preference and ectopic projection is a convergent mechanism to alter innate odor valence
Project description:Elucidating cytosine modification difference between human populations can enhance our understanding of ethnic specificity in complex traits such as disease predisposition and drug response. In this study, cytosine modification levels in 133 HapMap lymphoblastoid cell lines (LCLs) derived from individuals of European or African ancestry were profiled using the Illumina HumanMethylation450 BeadChip. Approximately 13% of the analyzed CpG sites showed differential modification between the two populations at false discovery rate (FDR) of 1%. CpG sites with greater modification levels in European descents were enriched in the proximal regulatory regions, while those greater in African descents were biased toward gene bodies. More than half of the detected population-specific cytosine modifications could be explained by genetic variation. A substantial proportion of local modification quantitative trait loci (mQTL) exhibited population-specific effects, suggesting that genetic epistasis and/or genotype × environment interaction could be common. Distinct inter-individual correlations were observed between gene expression and cytosine modifications in both proximal promoters and gene bodies, demonstrating a regulatory role of inter-individual variation in cytosine modification. Furthermore, a number of SNPs (single nucleotide polymorphisms) previously identified for complex traits with known racial disparities could be annotated as mQTLs for population-specific CpGs. Our findings revealed abundant population-specific cytosine modifications and the underlying genetic basis, as well as the relatively independent contribution of genetic and epigenetic variations to population differences in gene expression. 60 HapMap CEU and 73 HapMap YRI samples from Coriell Insitute were profiled for cytosine modification levels.