The high prevalence and health impact of obesity drives a critical need to understand the link between obesity and disease. Monocyte and macrophage activation that contributes to low grade inflammation is one such link. These myeloid cells contribute to inflammation by producing proinflammatory cytokines, activating other immune cells, and monocytes can also differentiate into proinflammatory macrophages, all of which are associated with insulin resistance. However, the mechanisms underlying myeloid cell proinflammatory activation in human obesity and diabetes are not resolved. My preliminary data identify lysosomal dysfunction in SRhi myeloid cells as high priority targets for investigation in diabetes. Furthermore, strategies to alleviate inflammation in metabolic disease have been ineffective, partly due to low cellular specificity. We identify polymer nanoparticles (NPs) as excellent candidates for a more specific approach. My preliminary data show increased NP-monocyte interactions in obese diabetic patients vs. non-diabetic, making NPs a promising approach for targeting myeloid cells in diabetes. My central hypothesis is that obesity disrupts SRhi myeloid cell lysosomal processing, increasing production of inflammatory mediators, and that NPs can modulate SRhi myeloid cell inflammatory activation. To examine this hypothesis, I will use monocytes and ATMs from a valuable obese bariatric surgery cohort, focusing on diabetic vs. non-diabetic comparisons in two research aims: (1) Identify the genes and pathways by which myeloid cells are dysregulated in human obesity. I will use a combination of powerful, unbiased high-throughput genomics platforms with novel bioinformatics tools to identify specific pathways and regulators in SRhi myeloid cells from diabetic patients. I will use assays of endocytosis and lysosomal function, proinflammatory cytokines, and flow cytometry to determine functional changes in SRhi myeloid cell subtypes in diabetes. (2) Determine the specificity and efficacy of NPs for myeloid cell modulation in human obesity. I will test internalization and impact of NPs on human SRhi myeloid cell subtypes, determining whether they can attenuate proinflammatory signatures through cytokine assays and RNA-seq. By completing these aims I will identify the molecular and cellular signatures mediating activation of SRhi myeloid cells and determine efficacy of novel NP-therapeutics to modulate SRhi myeloid cells in human metabolic disease. I will gain expertise in nanotechnology and high-throughput genomics platforms. The mentorship team will be led by co-primary mentors Dr. Robert O'Rourke and Dr. Lonnie Shea. Dr. O'Rourke is an expert in human obesity and clinical biosamples. Dr. Shea is an internationally recognized researcher at the interface of regenerative medicine, drug and gene delivery, and immune tolerance. Co-primary mentors and experts in immunometabolism, diabetes, obesity, and genomics and bioinformatics will guide me in completing the research and training proposed. Completing these goals will be a critical step toward independent research in translational immunology and immunometabolism.
Obesity is associated with health risks such as diabetes and cardiovascular disease, but the mechanisms contributing to obesity-related disease are poorly understood. Inflammation and activated immune cells in circulation have been identified as links between obesity and disease. Identifying how these cells are activated in obesity and how immune-modifying particles affect them could provide novel therapeutic targets and approaches as well as indicators that help us identify human populations that are the most at-risk for metabolic and cardiovascular disease.