Journal
FASEB JOURNAL
Volume 33, Issue 3, Pages 3549-3561Publisher
WILEY
DOI: 10.1096/fj.201801855R
Keywords
diabetes; iron uptake; HIF2 ubiquitination
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Funding
- American Heart Association Scientist Development Grant [13SDG1623001]
- U.S. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases [DK107719]
- National Science Fund of China (NSFC) [81503514]
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Excessive iron increases the incidence of diabetes and worsens diabetic complications. Reciprocally, diabetes induces iron loading, partially attributable to elevated intestinal iron export according to a recent report. Herein, we show that iron uptake and the mRNA expression of iron importer divalent metal transporter 1 (DMT1) were significantly increased in the duodenum of streptozotocin-induced diabetic mice. Immunofluorescence staining of human intestinal biopsies revealed increased brush border membrane (BBM) and decreased cytoplasmic DMT1 expression in patients with diabetes, suggesting translocation of DMT1. This pattern of DMT1 regulation was corroborated by immunoblotting results in diabetic mice showing that BBM DMT1 expression was increased by 210%, in contrast to a 60% increase in total DMT1. PKC mediates many diabetic complications, and PKC activity was increased in diabetic mouse intestine. Intriguingly, diabetic mice with PKC deficiency did not show increases in iron uptake and BBM DMT1 expression. High-glucose treatment increased plasma membrane DMT1 expression via the activation of PKC in cultured IECs. Inhibition of PKC potentiated the ubiquitination and degradation of DMT1 protein. We further showed that high glucose suppressed membrane DMT1 internalization. These findings demonstrate that PKC promotes microvillus membrane DMT1 expression and intestinal iron uptake, contributing to diabetic iron loading.Zhao, L., Bartnikas, T., Chu, X., Klein, J., Yun, C., Srinivasan, S., He, P. Hyperglycemia promotes microvillus membrane expression of DMT1 in intestinal epithelial cells in a PKC-dependent manner.
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