Nature medicine
-
Reactive oxygen species (ROS) induce chemokines responsible for the recruitment of inflammatory cells to sites of injury or infection. Here we show that the plasma membrane Ca(2+)-permeable channel TRPM2 controls ROS-induced chemokine production in monocytes. In human U937 monocytes, hydrogen peroxide (H(2)O(2)) evokes Ca(2+) influx through TRPM2 to activate Ca(2+)-dependent tyrosine kinase Pyk2 and amplify Erk signaling via Ras GTPase. ⋯ In the dextran sulfate sodium-induced colitis inflammation model, CXCL2 expression, neutrophil infiltration and ulceration were attenuated by Trpm2 disruption. Thus, TRPM2 Ca(2+) influx controls the ROS-induced signaling cascade responsible for chemokine production, which aggravates inflammation. We propose functional inhibition of TRPM2 channels as a new therapeutic strategy for treating inflammatory diseases.
-
Obesity and metabolic syndrome are increasingly recognized as major risk factors for cardiovascular disease. Herein we show that Krüppel-like transcription factor 5 (KLF5) is a crucial regulator of energy metabolism. Klf5(+/-) mice were resistant to high fat-induced obesity, hypercholesterolemia and glucose intolerance, despite consuming more food than wild-type mice. ⋯ Upon agonist stimulation of PPAR-delta, KLF5 was deSUMOylated, and became associated with transcriptional activation complexes containing both the liganded PPAR-delta and CREB binding protein (CBP). This activation complex increased the expression of Cpt1b, Ucp2 and Ucp3. Thus, SUMOylation seems to be a molecular switch affecting function of KLF5 and the transcriptional regulatory programs governing lipid metabolism.