Wei, Zong

Pancreatic β cells secrete insulin in response to glucose, a process that is regulated at multiple levels, including a network of input signals from other organ systems. Impaired islet function contributes to the pathogenesis of type 2 diabetes mellitus (T2DM), and targeting inter‐organ communications, such as GLP‐1 signalling, to enhance β‐cell function has been proven to be a successful therapeutic strategy in the last decade. In this review, we will discuss recent advances in inter‐organ communication from the metabolic, immune and neural system to pancreatic islets, their biological implication in normal pancreas endocrine function and their role in the (mal)adaptive responses of islet to nutrition‐induced stress.

Significance Macrophages regulate many aspects of the innate immune response and the activation of adaptive immunity following exposure to microbial ligands. However, macrophages can also contribute to inflammation underlying diseases such as atherosclerosis and obesity. Epigenetic regulators control inflammatory gene regulation and, as such, are potential targets for modulation of the inflammatory response. Here, we show that inhibitors and degraders of the bromodomain protein BRD9, a subunit of the noncanonical BAF complex, limit inflammation by specifically blocking the induction of interferon-stimulated genes. This effect overlaps with the transcriptional responses with the BET inhibitor JQ1 but affects fewer genes and is more specific in scope. Our results suggest that BRD9 inhibitors/degraders may be therapeutically relevant agents to limit interferon-associated inflammation.

Significance Glucocorticoids are widely prescribed antiinflammatory drugs that suppress inflammatory gene expression through activation of the glucocorticoid receptor (GR); however, the mechanisms of GR-mediated repression are not fully understood. We show here that bromodomain containing 9 (BRD9), a component of the SWI/SNF chromatin remodeling complex, modulates GR activity in bone marrow-derived macrophages. Loss of BRD9 activity in macrophages attenuated the response to liposaccharides and interferon inflammatory stimuli. Notably, BRD9 inhibition synergized with the synthetic glucocorticoid dexamethasone to suppress the inflammatory response in macrophages. Our data support a model in which BRD9 restricts GR binding at a subset of inflammatory related genes, and suggests that BRD9 inhibitors may increase the efficacy of glucocorticoids.