Aberrant Increase in Lipid Synthesis Exacerbates Diabetic Nephropathy and Folic Acid-induced Kidney Injury.
10.11714/jsysu.med.YX20250152
- VernacularTitle:脂质合成异常增多加重糖尿病肾病和叶酸诱导的肾损伤
- Author:
Yuzhi CHEN
1
;
Xiaoyun JIANG
1
;
Qihui DAI
1
;
Gonghua HUANG
1
;
Xinguang LIU
1
;
Meng YANG
1
Author Information
1. Guangdong Provinvial Key Laboratory of Medical Immunology and Molecular Diagnostics//Institute of Aging Research//Institute of Biochemistry & Molecular Biology，School of Medical Technology， Guangdong Medical University， Dongguan 523808， China
- Publication Type:Journal Article
- Keywords:
folic acid-induced kidney injury;
diabetic nephropathy;
fatty acid metabolism;
lipid accumulation;
cellular senescence;
fibrosis
- From:
Journal of Sun Yat-sen University(Medical Sciences)
2026;47(1):119-132
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo investigate the changes and effects of fatty acid metabolism in folic acid （FA）-induced kidney injury and diabetic nephropathy （DN） mouse models. MethodsThe FA-induced kidney injury model was established via intraperitoneal injection of FA. Nine adult C57BL/6J mice were randomly allocated to two groups： saline control group （Saline， n=5） and FA intervention group （n=4）. Mice in the FA group received a single intraperitoneal injection of FA （250 mg/kg）， whereas those in the Saline group were administered an equivalent volume of normal saline. The DN model was constructed using a high-fat diet combined with streptozotocin （STZ） injection. Eleven adult C57BL/6J mice were randomly divided into two groups： normal diet control group （ND， n=6） and DN model group （DN， n=5）. The ND group was fed a normal diet throughout the experiment； the DN group was maintained on a high-fat diet for 8 weeks， followed by a single intraperitoneal injection of STZ （100 mg/kg）， and then continued on the high-fat diet until week 16. （1） Hematoxylin and eosin （HE） and sirius red staining were used to observe pathological changes in the kidneys of the four groups of mice. （2） RNA-Seq was performed on mouse kidney tissues to screen for differentially expressed genes （DEGs）， followed by Gene Ontology （GO）， Kyoto Encyclopedia of Genes and Genomes （KEGG）， and Gene Set Enrichment Analysis （GSEA）. RT-qPCR was used to detect the mRNA levels of fatty acid synthesis and fibrosis-related genes. Lipid droplet accumulation was assessed by Oil Red O staining on frozen kidney sections. （3） Human renal cortical proximal tubular epithelial cells （HK-2） and proximal tubular epithelial cells （PTECs） were treated with 10 ng/mL recombinant human TGF-β1 or high glucose. RT-qPCR was used to measure the mRNA levels of fatty acid synthesis and fibrosis-related genes in HK-2 cells. Lipid droplet accumulation in HK-2 cells and PTECs was detected using Bodipy 493/503 staining. （4） HK-2 cells were treated with 100 µmol/L palmitic acid （PA）. Bodipy 493/503 staining was used to evaluate lipid droplet accumulation. （5） SA-β-gal staining was used to assess senescence in kidney tissues from all four mouse groups. Cellular senescence and the expression of senescence-associated secretory phenotype （SASP） factors in PA-treated HK-2 cells were assessed using SA-β-gal staining， Western blot， and RT-qPCR. The effect of PA-treated PTECs on renal fibroblast activation was assessed by immunofluorescence. Results（1） Both FA and DN groups showed pathological changes in kidney tissue， including renal tubular structural damage and collagen fiber deposition. （2） DEGs in both FA and DN groups were significantly enriched in metabolism-related pathways， especially lipid metabolism pathways. Compared to the Saline control， the expression of fatty acid synthesis genes Srebp1 and Fasn was significantly upregulated in the FA group （Srebp1： t=2.445， P=0.044 4； Fasn： t=2.571， P=0.037 0）. Compared to the ND group， Srebp1， Acc1， and Fasn gene expression was upregulated in the DN group （Srebp1： t=3.354， P=0.010 0； Acc1： t=2.602， P=0.031 5； Fasn： t=2.358， P=0.046 1）. The fibrosis-related gene Col1a1 was also upregulated in both FA and DN groups （FA： t=2.628， P=0.034 0； DN： t=3.602， P=0.007 0）， accompanied by pathological signs of lipid accumulation. （3） In HK-2 cells treated with TGF-β1 or high glucose， the mRNA expression levels of SREBP1 （F=15.41， P=0.004 3； TGFβ： P=0.002 9； HG： P=0.045 2）， ACC1 （F=30.30， P=0.000 7； HG： P=0.001 4）， and FASN （F=18.76， P=0.002 6； TGFβ： P=0.001 7； HG： P=0.031 0） were significantly upregulated. Both treatments also induced lipid accumulation in HK-2 cells and PTECs. （4） There was an increase in senescent cells in the kidneys of both the FA and DN groups. PA treatment induced lipid accumulation， accelerated senescence， and activated fibroblasts in renal tubular epithelial cells. ConclusionsTranscriptional abnormalities of lipid metabolism-related genes were observed in the kidneys of both FA-induced kidney injury and diabetic nephropathy models. Excessive fatty acid synthesis leads to lipid accumulation， which induces senescence in PTECs and ultimately promotes the development and progression of fibrosis.
