Background: Diabetic nephropathy (DN) is an increasing threat to human health and regarded to be the leading cause of end-stage renal disease worldwide. Exosomes delivery may play a key role in cross-talk among kidney cells and the progression of DN. However, the mechanisms underlying exosomes in DN remain unclear.
Methods: The cross-disciplinary study, including in vivo, in vitro, and human studies was conducted to explore the cross-talk between proximal tubular epithelial cells (PTECs) and mesangial cells (MCs) in DN. We purified exosome from PTECs treated with high glucose and db/db mice and assessed their influences in the pathologic change of MCs and downstream signal pathway. Healthy individuals and type 2 diabetic patients were enrolled to examine the role of exosomes in clinical applications.
Results: High glucose stimulated PTECs to secrete exosomal miR-92a-1-5p, which was taken-up by glomerular MCs, inducing myofibroblast transdifferentiation (MFT) in vitro and in vivo. PTEC-released exosomal 92a-1-5p decreased reticulocalbin-3 expression, leading to endoplasmic reticulum (ER) stress by downregulating genes essential for ER homeostasis including calreticulin and mesencephalic astrocyte-derived neurotrophic factor. Treatment with miR-92a-1-5p inhibitor ameliorated kidney damage in db/db mice with DN. Urinary miR-92a-1-5p could predict kidney injury in type 2 diabetic patients.
Conclusions: PTEC-derived exosomal miR-92a-1-5p modulated the kidney microenvironment in vivo and in vitro models, which altered ER stress and MFT in MCs resulting in DN progression. Further blocking miR-92a-1-5p epigenetic regulatory network could be a potential therapeutic strategy to prevent the progression of DN. Video Abstract.
Keywords: Diabetic nephropathy; ER stress; Exosome; Mesangial cell; Myofibroblast transdifferentiation; Proximal tubular epithelial cell; miR-92a-1-5p.
Diabetic nephropathy (DN) has been the leading cause of end-stage renal disease worldwide. Exosomes play a principle role in cross-talk of kidney cells and further affect the onset or progression of DN. This study firstly demonstrated the communication between proximal tubular epithelial cells (PTECs) and mesangial cells (MCs) through exosome transmission. PTEC-released exosomal 92a-1-5p induced endoplasmic reticulum stress and epithelial-mesenchymal transition in MCs through reticulocalbin-3 modulation. Kidney damage was rescued in DN mice after treatment with miR-92a-1-5p inhibitor. Moreover, urinary exosomal miR-92a-1-5p could predict DN progression in type 2 diabetic patients. These findings prove the impact of exosomal miR-92a-1-5p on pathophysiologic mechanisms and its potential use in clinical care and prediction of DN.
© 2023. The Author(s).