Selective targeting of visceral adiposity by polycation nanomedicine

Obesity is a pandemic health problem with poor solutions, especially for targeted treatment. Here we develop a polycation-based nanomedicine to selectively target visceral adiposity, the more metabolically detrimental and manipulation-resistant fat. We demonstrated that the polycationic polymer polyamidoamine (PAMAM) generation 3 (P-G3) was specifically enriched in the visceral fat due to its high charge density when delivered intraperitoneally. Moreover, P-G3 treatment of obese mice inhibited visceral adiposity, increased energy expenditure, prevented obesity, and alleviated the associated metabolic dysfunctions. In vitro adipogenesis models and single-cell RNA sequencing (scRNA-seq) revealed that P-G3 paradoxically uncouples the defining function of adipocyte - lipid synthesis and storage - from adipocyte development to create unique “dwarf” adipocytes that possess normal adipocyte functions but are deficient in hypertrophic growth at least through synergistically modulating NAD and mTOR pathways. The visceral fat distribution of P-G3 was further enhanced by modifying P-G3 with cholesterol to form lipophilic nanoparticles, which were also effective in treating obesity. Our study highlights an unexpected strategy to tackle visceral adiposity and champions a new direction of exploring cationic nanomaterials for treating metabolic diseases. 3T3-L1 cells were cultured and differentiated into adipocytes. Cells (treated with or without PAMAM polymers) were collected at differentiation Day 0, 3, and 6 as preadipocytes, early adipogenesis, and mature adipocytes for single cell sequencing.