Chromatin remodeling factors and mechanisms in diabetic microvascular complications

PROJECT SUMMARY Type 2 diabetes (T2D)-associated vascular dysfunction and inflammation drives the development of several debilitating microvascular complications (MVC, e.g., retinopathy and nephropathy). Despite various treatment options, morbidity/mortality from MVC is augmented. Thus, there is a critical unmet need for in-depth examination of the underlying mechanisms that can lead to improved therapies. Increased activation of monocytes and macrophages (Monos/Macs) instigated by diabetogenic factors (i.e., high glucose, cytokines, lipids) play vital roles in inflammatory diabetic MVC. Our studies have demonstrated the roles of epigenetic mechanisms in modulating inflammatory genes/processes/functions in mouse (m) and human (h) Monos/Macs under diabetic conditions and in metabolic memory. Our long-term goal is to understand how diabetes-induced changes in key nuclear factors control specific epigenotypes and long-range chromosomal interactions to reprogram the 3D epigenome and regulate inflammatory gene expression. Our exciting new data shows that; i) T2D h- and m- Monos/Macs, as well as T2D m-kidney/adipose tissues are deficient in JARID2 (JD2), a DNA binding and chromatin remodeling protein; ii) in h-Macs, JD2 knockdown (JD2-KD) activates, while JD2 overexpression (JD2- OE) attenuates inflammatory responses; iii) RNA-seq analyses after JD2-KD revealed that JD2 target genes are associated with Macs dysfunction in MVC; iv) integrative epigenomics analysis in h-Macs revealed that diabetic conditions (and reduced JD2) dysregulate chromatin accessibility and the enhancer connectome at inflammatory gene loci and JD2 target genes; v) novel lipid nanoparticles (LNPs) are viable for JD2 delivery to Macs and target organs in vivo in T2D mice, and reduce inflammatory genes and MVC (nephropathy). The rationale is that an in- depth understanding of the anti-inflammatory roles of JD2 and its pivotal regulation of epigenome and chromatin organization can lay the foundation for novel therapeutic strategies to curb inflammation and related MVC in T2D. Our central hypothesis is that downregulation of JD2 in T2D reprograms the epigenome and the 3D chromatin architecture in Monos/Macs, and leads to the hyperinflammatory state that drives T2D-related MVC. These adverse changes are ameliorated by JD2 reconstitution. This will be tested via 3 Specific Aims: 1) Determine the functional roles of JD2 in diabetes-induced dysregulated phenotype of Monos/Macs associated with MVC; 2) Elucidate the role of JD2 in diabetes-reprogrammed epigenome and 3D chromatin architecture driving h-Monos/Macs dysfunction; 3) Determine the therapeutic potential of augmenting JD2 with LNPs in vivo to ameliorate Macs dysfunction and MVC in diabetes. This innovative study will synergize expertise from chromatin biology, epigenetics, vascular biology, Omics analysis, vascular immunology and nanomedicine to tackle the unmet need for MVC management in T2D. These results will provide unique insights into the 3D epigenomic regulation of inflammation in T2D MVCs, and pioneer mRNA-LNP therapeutics in treating MVC. This study will also positively impact efforts to improve the quality of life of patients with T2D.