Bhlhe40/Sirt1 Axis-Regulated Mitophagy Is Implicated in All-Trans Retinoic Acid-Induced Spina Bifida Aperta

Abstract

Neural tube defects (NTDs) are the most severe congenital malformations that result from failure of neural tube closure during early embryonic development, and the underlying molecular mechanisms remain elusive. Mitophagy is the best-known way of mitochondrial quality control. However, the role and regulation of mitophagy in NTDs have not yet been elucidated. In this study, we used an all-trans retinoic acid (ATRA)-induced rat model to investigate mitophagy and its underlying mechanism in spina bifida aperta (SBA). The results of western blot, immunofluorescence and RT-qPCR analyses indicated that mitophagy was impaired and Sirt1 was downregulated in SBA. Administration of resveratrol-a strong specific Sirt1 activator-activated Sirt1, thus attenuating autophagy suppression and ameliorating SBA. RNA-sequencing and bioinformatics analysis results indicated that transcriptional regulation played an important role in NTDs. A luciferase reporter assay was performed to demonstrate that the transcription factor Bhlhe40 directly bound to and negatively regulated Sirt1 expression. Further, we discovered that the Bhlhe40/Sirt1 axis regulated mitophagy in neural stem cells. Collectively, our results for the first time demonstrate that Bhlhe40/Sirt1 axis regulated mitophagy is implicated in ATRA-induced SBA. Our findings provide new insights into pathogenesis of NTDs and a basis for potential therapeutic targets for NTDs.

Nuclear factor I-C disrupts cellular homeostasis between autophagy and apoptosis via miR-200b-Ambra1 in neural tube defects

“…Consistent with the findings of our previous study [ 13 ], a biochemical parameter for autophagy (the conversion of LC3-I to LC3-II) was repressed in the mouse model of ATRA-induced NTDs (Fig. 4A, B ).…”

“…The ability of autophagy to remove damaged cellular components is restricted in NTDs [ 11 , 12 ]. Furthermore, in a recent study, we determined that mitophagy in the spinal cord is inhibited in all-trans retinoic acid (ATRA)-induced spina bifida and that resveratrol treatment can reduce spina bifida formation by ameliorating mitophagy impairment; these findings indicate that autophagy is causally implicated in NTDs [ 13 ]. In addition, excessive apoptosis of neuroepithelial cells leads to an insufficient number of cells within the neural folds, which is another major factor in the formation of NTDs [ 14 , 15 ].…”

Baicalein Induces Mitochondrial Autophagy to Prevent Parkinson's Disease in Rats via miR-30b and the SIRT1/AMPK/mTOR Pathway

“…To study how miR-30b-5p participated in the regulation of autophagy, the targeted binding sites between miR-30b-5p and SIRT1 were predicted through the bioinformatics online website Transtarget 7.2 ( Figure 3A ). The regulation of SIRT1 in autophagy is repeatedly reported ( 23 , 24 , 35 ). The binding relationship between miR-30b-5p and SIRT1 was elucidated by a dual-luciferase assay ( Figure 3B ).…”

“…Mitochondrial autophagy is activated in cells through the activation of SIRT1 ( 23 ). The Bhlhe40/SIRT1 axis regulates mitochondrial autophagy in the neural stem cells ( 24 ). SIRT1 mediates the AMPK/mTOR pathway to induce mitochondrial autophagy ( 25 ).…”

Regulation of Mitophagy by Sirtuin Family Proteins: A Vital Role in Aging and Age-Related Diseases

“…In acute kidney injury and kidney fibrosis, enhanced mitophagy can also alleviate related symptoms via the activation of the SIRT1/PINK1/Parkin axis (Gao et al, 2020 ; Liu et al, 2020b ). Important roles of SIRT1-mitophagy have also been found in many other diseases, such as polycystic ovary syndrome (PCOS) (Yi et al, 2020 ), glioblastoma (Yao et al, 2018 ), spina bifida aperta (Zhao et al, 2021a ), age-related hearing loss (Xiong et al, 2019 ), and prostatic intraepithelial neoplasia (Di Sante et al, 2015 ). An increasing number of SIRT1-mediated mitophagy pathways have been identified in various diseases and aging processes, providing a basis and guidance for future therapeutic targets.…”