Douglas F. Dluzen

The gut microbiota plays a crucial role in early childhood development. Dysbiosis in this community has been linked to risk of disease. The transition from an exclusive milk-based diet to complementary feeding and eventual weaning is crucial for the development and maturation of the gut microbiota. However, the impact of breastfeeding duration during the complementary feeding period (typically 6 to 24 months of age) on microbial development trajectories remains incompletely characterized. Here, we investigated whether prolonged breastfeeding during the complementary feeding window influences gut microbiota succession by comparing children who continued breastfeeding with those who were fully weaned at the same ages. We analyzed 16S rRNA gene sequencing profiles of fecal samples collected from a cohort of Peruvian children at 6, 12, 18, and 24 months of age. Samples were categorized into two groups: a complementary feeding group (BF), which received both complementary foods and breast milk, and a post-weaning group (NBF), which had stopped receiving breast milk for over 7 days. We conducted both alpha and beta diversity to assess within- and between-sample microbial variation. Relative abundances of microbial taxa at the phylum and genus levels were also quantified. The results showed a clear age-related increase in both species richness and species evenness across early childhood, while BF had more gradual changes relative to NBF. Marked differences in community composition were observed between BF and NBF children at 12, 18, and 24 months, respectively. Children who continued breastfeeding maintained a Bifidobacterium-rich, lower-diversity microbiota for a longer period, whereas weaned children at the same age exhibited accelerated microbiota development toward an adult-like profile enriched in Bacteroidota and Bacillota (formerly Firmicutes). These findings suggest that breastfeeding during the complementary feeding period exerts a significant influence on gut microbiota development through the first two years of life, which is most likely independent of complementary food. The study provides potential implications for children’s health and nutrition guidelines from a perspective of gut microbiota succession.

Social factors influence health outcomes and life expectancy. Individuals living in poverty often have adverse health outcomes related to chronic inflammation that affect the cardiovascular, renal, and pulmonary systems. Negative psychosocial experiences are associated with transcriptional changes in genes associated with complex traits. However, the underlying molecular mechanisms by which poverty increases the risk of disease and health disparities are still not fully understood. To bridge the gap in our understanding of the link between living in poverty and adverse health outcomes, we performed RNA-sequencing of blood immune cells from 204 participants of the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study in Baltimore, Maryland. We identified 138 genes differentially expressed in association with poverty. Genes differentially expressed were enriched in wound healing and coagulation processes. Of the genes differentially expressed in individuals living in poverty, EEF1DP7 and VIL1 are also associated with hypertension in transcriptome-wide association studies. Our results suggest that living in poverty influences inflammation and the risk for cardiovascular disease through gene expression changes in immune cells.

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 peripheral blood mononuclear cells (PBMCs). DGE have also been associated with hypertension and cardiovascular disease (CVD) and correlate with race and sex. 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 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 an additional link to better understand the gene expression response in peripheral blood mononuclear cells in those living in poverty.

The prevalence of hypertension among African Americans (AAs) in the US is among the highest of any demographic and affects over two-thirds of AA women. Previous data from our laboratory suggest substantial differential gene expression (DGE) of mRNAs and microRNAs (miRNAs) exists within peripheral blood mononuclear cells (PBMCs) isolated from AA and white women with or without hypertension. We hypothesized that DGE by race may contribute to racial differences in hypertension. In a reanalysis of our previous dataset, we found that the Wiskott–Aldrich syndrome protein Verprolin-homologous protein 2 (WASF2 (also known as WAVE2)) is differentially expressed in AA women with hypertension, along with several other members of the actin cytoskeleton signaling pathway that plays a role in cell shape and branching of actin filaments. We performed an in silico miRNA target prediction analysis that suggested miRNA miR-1253 regulates WASF2. Transfection of miR-1253 mimics into human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs) significantly repressed WASF2 mRNA and protein levels (p < 0.05), and a luciferase reporter assay confirmed that miR-1253 regulates the WASF2 3′ UTR (p < 0.01). miR-1253 overexpression in HUVECs significantly increased HUVEC lamellipodia formation (p < 0.01), suggesting the miR-1253–WASF2 interaction may play a role in cell shape and actin cytoskeleton function. Together, we have identified novel roles for miR-1253 and WASF2 in a hypertension-related disparities context. This may ultimately lead to the discovery of additional actin-related genes which are important in the vascular-related complications of hypertension and influence the disproportionate susceptibility to hypertension among AAs in general and AA women in particular.

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 peripheral blood mononuclear cells (PBMCs). DGE have also been associated with hypertension and cardiovascular disease (CVD) and correlate with race and sex. 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 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 an additional link to better understand the gene expression response in peripheral blood mononuclear cells in those living in poverty.

Importance: Histone deacetylase 9 (HDAC9) has recently been demonstrated as a key regulator of vascular smooth muscle cell (VSMC) phenotype and is associated with abdominal aortic calcification, myocardial infarction and ischemic stroke. It is uncertain whether HDAC9 is also implicated in other VSMC-driven diseases.Objective: To investigate associations between abdominal aortic calcification-associated genetic variation in HDAC9 and VSMC-associated phenotypes.Design: Prospective population study.Setting: UK Biobank.Participants: 335,146 European, non-related person aged 40-69 years (mean 57±8 years, 54% women).Main outcomes: Blood pressure, heart rate, hypertension, myocardial infarction, stroke, arterial aneurysm, heart failure, glomerular filtration rate, albuminuria, end-stage renal disease, all-cause and cardiovascular mortality, HbA1c, diabetes, serum lipids, body mass index, and smoking.Results: We used the aortic calcification-raising A-allele of rs57301765 in HDAC9 as a genetic instrumental variable to query the long-term effects of HDAC9 variation. At the Bonferroni significance level, rs57301765 was associated with systolic blood pressure (effect per added risk allele in standard deviation units, 0.022; 95% CI, 0.016-0.029, P=1.71×10-11), pulse pressure (0.035; 95% CI, 0.028-0.041, P=5.76×10-27), hypertension (odds ratio, OR, 1.04; 95% CI, 1.02-1.05, P=1.26×10-6), myocardial infarction (OR, 1.08; 95% CI, 1.04-1.12, P=1.72×10-5, driven by non-ST segment elevation myocardial infarction, OR, 1.11; 95% CI, 1.04-1.17, P=0.001), and ischemic stroke (OR, 1.14; 95% CI, 1.07-1.22, P=6.29×10-5). There was a suggestive protective association with kidney disease outcomes that, however, did not reach experiment-wise significance. Look-ups in public genome-wide association study results concur with our findings for cardiovascular outcomes.Conclusions and Relevance: The genetic results in our study lend further support for HDAC9 as a key determinant of VSMC-associated cardiovascular pathology and its potential as a therapeutic target for arterial stenotic and calcific disease.

The prevalence of hypertension among African Americans (AAs) in the US is among the highest of any demographic and affects over two-thirds of AA women. Previous data from our laboratory suggests substantial differential gene expression (DGE) of mRNAs and microRNAs (miRNAs) exists within peripheral blood mononuclear cells (PBMCs) isolated from AA and white women with or without hypertension. We hypothesized that DGE by race may contribute to racial differences in hypertension. We found that the Wiskott-Aldrich syndrome protein Verprolin homologous-2 ( WAVE2 ) is differentially-expressed in AA women with hypertension, along with several other members of the actin cytoskeleton signaling pathway that plays a role in cell shape and branching of actin filaments. We performed an in silico miRNA target prediction analysis that suggested miRNA miR-1253 regulates WAVE2. Transfection of miR-1253 mimics into human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs) significantly repressed WAVE2 mRNA and protein levels ( P WAVE2 3’ UTR ( P P <0.01), suggesting the miR-1253/WAVE2 interaction may play a role in endothelial cell shape and actin cytoskeleton function. Together, we have identified novel roles for miR-1253 and WAVE2 in a hypertension-related disparities context. This may ultimately lead to the discovery of additional actin-related genes which are important in the vascular-related complications of hypertension and influence the disproportionate susceptibility to hypertension among AAs in general and AA women in particular.

Accurate predictions across multiple fields of microbiome research have far-reaching benefits to society, but there are few widely accepted quantitative tools to make accurate predictions about microbial communities and their functions. More discussion is needed about the current state of microbiome analysis and the tools required to overcome the hurdles preventing development and implementation of predictive analyses.

Summary: Circulating extracellular RNAs (exRNAs) are potential biomarkers of disease. We thus hypothesized that age‐related changes in exRNAs can identify age‐related processes. We profiled both large and small RNAs in human serum to investigate changes associated with normal aging. exRNA was sequenced in 13 young (30–32 years) and 10 old (80–85 years) African American women to identify all RNA transcripts present in serum. We identified age‐related differences in several RNA biotypes, including mitochondrial transfer RNAs, mitochondrial ribosomal RNA, and unprocessed pseudogenes. Age‐related differences in unique RNA transcripts were further validated in an expanded cohort. Pathway analysis revealed that EIF2 signaling, oxidative phosphorylation, and mitochondrial dysfunction were among the top pathways shared between young and old. Protein interaction networks revealed distinct clusters of functionally‐related protein‐coding genes in both age groups. These data provide timely and relevant insight into the exRNA repertoire in serum and its change with aging.