Diabetic dysbiosis has been described as a novel key player in diabetes and diabetic complications. However, the cellular/molecular alterations associated with dysbiosis remain poorly characterized. For that, control, non-obese type 2 diabetic MKR mice and MKR mice treated with butyrate were used to delineate the epigenetic, cellular and molecular mechanisms by which dysbiosis associated with diabetes induces colon shortening and inflammation attesting to gastrointestinal disturbance. Our results show that dysbiosis is associated with T2DM and characterized by reduced Bacteroid fragilis population and butyrate-forming bacteria. The reduction of butyrate-forming bacteria and inadequate butyrate secretion result in alleviating HDAC3 inhibition and altering colon permeability. The observed changes are also associated with an increase in ROS production, a rise in NOX4 proteins, and a shift in the inflammatory markers, where IL-1β is increased and IL-10 and IL-17α are reduced. Treatment with butyrate restores the homeostatic levels of NOX4 and IL-1β. In summary, our data suggest that in T2DM, dysbiosis is associated with a reduction in butyrate content leading to increased HDAC3 activity. Butyrate treatment restores the homeostatic levels of the inflammatory markers and reduces ROS production known to mediate diabetes-induced colon disturbance. Taken together, our results suggest that butyrate could be a potential treatment to attenuate diabetic complications.
Mohamed H Noureldein, Sara Bitar, Natalie Youssef, Sami Azar, and Assaad A Eid
Rachel Njeim, William S Azar, Angie H Fares, Sami T Azar, Hala Kfoury Kassouf, and Assaad A Eid
NETosis, a novel form of neutrophil-related cell death, acts as a major regulator of diabetes and diabetes-associated complications. In this review, we show that the extrusion of neutrophil extracellular traps, termed NETs, plays an important role in the pathogenesis of type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and diabetes-induced complications. In T1DM, β-cell death induces the sequestration of neutrophils in the pancreas and seems to be correlated with increased NETosis. In T2DM patients, products of NETs release are significantly elevated. Increased levels of dsDNA are correlated with the presence of cardiovascular disease and diabetic kidney disease, further supporting the role of NETosis in the pathogenesis of other diabetes-induced complications such as impaired wound healing and diabetic retinopathy. NETosis is induced by high glucose through incompletely understood mechanisms, but it also appears to be elevated in patients with diabetes who have tightly controlled glucose levels. We hypothesize that hyperglycemia worsens the already elevated baseline of NETosis in diabetic patients to further increase its detrimental effects.