Online_Supplemental_Materials.doc (27.53 MB)
MANF Promotes Diabetic Corneal Epithelial Wound Healing and Nerve Regeneration by Attenuating Hyperglycaemia-Induced Endoplasmic Reticulum Stress
figure
posted on 2020-04-21, 21:05 authored by Ada AdminAda Admin, Xiaochuan Wang, Weina Li, Qingjun Zhou, Jing Li, Xiaolei Wang, Jing Zhang, Dewei Li, Xia Qi, Ting Liu, Xiaowen Zhao, Suxia Li, Lingling Yang, Lixin XieMesencephalic
astrocyte-derived neurotrophic factor (MANF) is a neurotrophic factor widely
expressed in mammalian tissues and exerts critical protective effects on
neurons and other cell types in various disease models, such as those for
diabetes. However, to date, the expression and roles of MANF in the cornea,
with or without diabetic keratopathy (DK), remain unclear. Here, we demonstrated that MANF is abundantly expressed in normal corneal
epithelial cells, however, MANF expression was significantly reduced in both unwounded
and wounded corneal epithelium in STZ-induced type 1 diabetic C57BL/6 mice. Recombinant MANF significantly promoted normal and
diabetic corneal epithelial wound healing and nerve regeneration. Furthermore,
MANF inhibited hyperglycaemia-induced endoplasmic reticulum (ER) stress and ER
stress-mediated apoptosis. Attenuation of ER stress with 4-phenylbutyric acid (4-PBA)
also ameliorated corneal epithelial closure and nerve regeneration. However,
the beneficial effects of MANF and 4-PBA were abolished by an Akt inhibitor and
Akt-specific siRNA. Finally, we revealed that the
subconjunctival injection of MANF-specific siRNA prevented corneal epithelial
wound healing and nerve regeneration. Our
results provide important evidence that hyperglycaemia-suppressed MANF
expression may contribute to delayed corneal epithelial wound healing and
impaired nerve regeneration by increasing ER stress, and MANF may be a useful
therapeutic modality for treating DK.