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Research
ATF4 promotes renal tubulointerstitial fibrosis by suppressing autophagy in diabetic nephropathy
Ya Xiao
Jinan University
Corresponding Author
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This work is licensed under a CC BY 4.0 License. Read Full License
Background
Diabetic nephropathy (DN) is the dominant cause of end-stage renal disease which is characterized by extracellular matrix accumulation. The purpose of this study was to investigate the role of activating transcription factor 4 (ATF4) in regulating renal fibrosis and autophagy in DN.
Methods
Streptozotocin (STZ) was administered to heterozygous ATF4 knockout (KO) and wild-type (WT) mice via an intraperitoneal injection to induce DN. NRK-52E cells were cultured in high glucose to mimic diabetic pathological. qRT-PCR, western blot, immunofluorescence, histology and electron microscopic analysis were performed. The autophagy flow was observed by tandem mRFP-GFP-LC3 fluorescence microscopy.
Results
DN mice experienced severe renal injury and fibrosis and showed increased expression of ATF4 and inhibition of autophagy in kidney tissues. STZ-induced ATF4 KO mice showed significant improvement in urinary albumin, serum creatinine and blood urea nitrogen and the pathological changes of renal tubulointerstitial fibrosis compared with STZ-induced WT mice. Furthermore, western blot assays and immunofluorescence staining revealed that inhibition of ATF4 could restore autophagy in DN mice. Overexpression of ATF4 in NRK-52E cells cultured in high glucose condition suppressed autophagy and upregulated Col-IV expression, while inhibition of ATF4 could increase the number of the autophagosomes, improve autophagic flux and decrease Col-IV level.
Conclusion
Our study provided the first evidence of a crucial role for ATF4 in inhibiting autophagy against diabetic kidney damage. Suppression of ATF4 may be an effective therapy in restraining renal tubulointerstitial fibrosis in DN.
Keywords
Autophagy, diabetic nephropathy, renal tubulointerstitial fibrosis, activated transcription factor-4
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This is a preprint. It has not completed peer review.
Research
ATF4 promotes renal tubulointerstitial fibrosis by suppressing autophagy in diabetic nephropathy
Ya Xiao
Jinan University
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 03 Jun, 2020
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Translational Medicine
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background
Diabetic nephropathy (DN) is the dominant cause of end-stage renal disease which is characterized by extracellular matrix accumulation. The purpose of this study was to investigate the role of activating transcription factor 4 (ATF4) in regulating renal fibrosis and autophagy in DN.
Methods
Streptozotocin (STZ) was administered to heterozygous ATF4 knockout (KO) and wild-type (WT) mice via an intraperitoneal injection to induce DN. NRK-52E cells were cultured in high glucose to mimic diabetic pathological. qRT-PCR, western blot, immunofluorescence, histology and electron microscopic analysis were performed. The autophagy flow was observed by tandem mRFP-GFP-LC3 fluorescence microscopy.
Results
DN mice experienced severe renal injury and fibrosis and showed increased expression of ATF4 and inhibition of autophagy in kidney tissues. STZ-induced ATF4 KO mice showed significant improvement in urinary albumin, serum creatinine and blood urea nitrogen and the pathological changes of renal tubulointerstitial fibrosis compared with STZ-induced WT mice. Furthermore, western blot assays and immunofluorescence staining revealed that inhibition of ATF4 could restore autophagy in DN mice. Overexpression of ATF4 in NRK-52E cells cultured in high glucose condition suppressed autophagy and upregulated Col-IV expression, while inhibition of ATF4 could increase the number of the autophagosomes, improve autophagic flux and decrease Col-IV level.
Conclusion
Our study provided the first evidence of a crucial role for ATF4 in inhibiting autophagy against diabetic kidney damage. Suppression of ATF4 may be an effective therapy in restraining renal tubulointerstitial fibrosis in DN.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6