Stress-induced myonectin improves glucose homeostasis by inhibiting glycemic response to HPA axis

Abstract

Inhibiting glycemic response to HPA axis contributes to glycemic control for diabetic patients. Here, mice were subjected to high-fat diet and intermittent chronic stress, and glucose homeostasis and lipolysis were determined during the intervention. Firstly, we found that glucose intolerance appears at the earliest, followed by reduced insulin sensitivity and increased epinephrine (EPI) sensitivity in the early stage of diet-induced obesity. Next we investigated whether chronic stress impairs glycemic control and which mediates its effects. Short-term stress training raises serum and skeletal muscle myonectin (Myn) levels and improves glucose intolerance. Stress attenuates blood glucose and glycerol responses to EPI, but enhances lipolytic response to EPI in adipose tissues. Myn overexpression in vivo improves glucose tolerance and enhances insulin sensitivity at the cost of blunting glycemic responses to EPI. Myn knockdown reduces beneficial effects of stress or exercise on glucose homeostasis. Together, myonectin is a stress-induced myokine that readjusts glycemic and metabolic responses to HPA axis, and thus prevent the progression of glucose intolerance and obesity. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=122 SRC="FIGDIR/small/838003v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@42b09forg.highwire.dtl.DTLVardef@59a744org.highwire.dtl.DTLVardef@1f4a01dorg.highwire.dtl.DTLVardef@13bda27_HPS_FORMAT_FIGEXP M_FIG C_FIG One Sentence SummaryChronic stress breaks glucose intolerance cycle to resist diet-induced obesity, through myonectin-mediated inhibition of glycemic response to epinephrine (EPI) and activation of insulin signaling in adipose tissues. HighlightsO_LIEPI sensitivity increases after glucose intolerance and with reduced insulin sensitivity in diet-induced obesity C_LIO_LIChronic stress blunts glycemic responses to EPI and increases myonectin levels in serum and skeletal muscle C_LIO_LIMyonectin attenuates glycemic response to EPI and improves metabolic profile in HFD-fed mice C_LIO_LIReducing myonectin reverses beneficial effects of stress on glucose homeostasis C_LI