The Association between Poverty and Gene Expression within Immune Cells in a Diverse Baltimore City Cohort

Socioeconomic status (SES), living in poverty, and other social determinants of health contribute to health disparities in the United States. African American (AA) men living below poverty in Baltimore City have a higher incidence of mortality when compared to either white males or AA females living below poverty. Previous studies in our laboratory and elsewhere suggest that environmental conditions are associated with differential gene expression (DGE) patterns in white blood cells, and this may contribute to the onset of diseases in the immune or cardiovascular systems. DGE have also been associated with hypertension and cardiovascular disease (CVD) and correlate with race and gender. However, no studies have investigated how poverty status associates with DGE between male and female AAs and whites living in Baltimore City. We examined DGE in 52 AA and white participants of the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) cohort, who were living above or below 125% of the 2004 federal poverty line at time of sample collection. We performed a microarray to assess DGE patterns in peripheral blood mononuclear cells (PBMCs) from these participants. AA males and females living in poverty had the most genes differentially-expressed compared with above poverty controls. Gene ontology (GO) analysis identified unique and overlapping pathways related to the endosome, single-stranded RNA binding, long-chain fatty-acyl-CoA biosynthesis, toll-like receptor signaling, and others within AA males and females living in poverty and compared with their above poverty controls. We performed RT-qPCR to validate top differentially-expressed genes in AA males. We found that KLF6, DUSP2, RBM34, and CD19 are expressed at significantly lower levels in AA males in poverty and KCTD12 is higher compared to above poverty controls. This study serves as initial link to better understand the biological mechanisms of poverty status with health outcomes and disparities. Total RNA from peripheral blood mononuclear cells (PBMCs) from 52 African-American (AA) and White female (F) and male (M) individuals 125% above or below the 2014 federal poverty line (N = 6-7 for each ethnicity, gender and poverty status group) were used to examine differential gene expression profiles by microarray analysis.