Amyloid-β Induces Hepatic Insulin Resistance In Vivo via JAK2

  1. Qiwei Zhai
  1. Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
  1. Corresponding author: Qiwei Zhai, qwzhai{at}sibs.ac.cn, or Yingying Le, yyle{at}sibs.ac.cn.
  1. Y.Z. and B.Z. contributed equally to this work.

Abstract

Amyloid-β (Aβ), a natural product of cell metabolism, plays a key role in the pathogenesis of Alzheimer’s disease (AD). Epidemiological studies indicate patients with AD have an increased risk of developing type 2 diabetes mellitus (T2DM). Aβ can induce insulin resistance in cultured hepatocytes by activating the JAK2/STAT3/SOCS-1 signaling pathway. Amyloid precursor protein and presenilin 1 double-transgenic AD mouse models with increased circulating Aβ level show impaired glucose/insulin tolerance and hepatic insulin resistance. However, whether Aβ induces hepatic insulin resistance in vivo is still unclear. Here we show C57BL/6J mice intraperitoneally injected with Aβ42 exhibit increased fasting blood glucose level, impaired insulin tolerance, and hepatic insulin signaling. Moreover, the APPswe/PSEN1dE9 AD model mice intraperitoneally injected with anti-Aβ neutralizing antibodies show decreased fasting blood glucose level and improved insulin sensitivity. Injection of Aβ42 activates hepatic JAK2/STAT3/SOCS-1 signaling, and neutralization of Aβ in APPswe/PSEN1dE9 mice inhibits liver JAK2/STAT3/SOCS-1 signaling. Furthermore, knockdown of hepatic JAK2 by tail vein injection of adenovirus inhibits JAK2/STAT3/SOCS-1 signaling and improves glucose/insulin tolerance and hepatic insulin sensitivity in APPswe/PSEN1dE9 mice. Our results demonstrate that Aβ induces hepatic insulin resistance in vivo via JAK2, suggesting that inhibition of Aβ signaling is a new strategy toward resolving insulin resistance and T2DM.

Footnotes

  • Received May 22, 2012.
  • Accepted October 6, 2012.

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  1. Diabetes vol. 62 no. 4 1159-1166
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