Hepatitis B virus X protein induces podocyte immune disorder by regulating Notch1 signaling pathway
10.3760/cma.j.cn441217-20240520-00527
- VernacularTitle:乙型肝炎病毒X蛋白通过调控Notch1信号通路诱导足细胞免疫紊乱
- Author:
Yitong YANG
1
;
Yuchao NIU
;
Shujian ZHANG
;
Leping SHAO
;
Weijie YUAN
Author Information
1. 青岛大学医学部第三临床医学院 青岛市市立医院肾内科，青岛 266071
- Keywords:
Hepatitis B virus;
Podocytes;
Receptor, Notch1;
Immune molecules;
Cytokines
- From:
Chinese Journal of Nephrology
2024;40(11):882-893
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the role of hepatitis B virus X protein (HBx) in glomerular podocyte immune disorder and its regulatory mechanism.Methods:Fourteen 6-week-old male hepatitis B virus (HBV) transgenic (HBV-Tg) mice were selected, and age-matched wild type (WT) mice were as controls. They were fed to different weeks, and 24 h urinary protein, blood biochemistry, renal pathology and podocyte changes under electron microscope were detected. The expression of HBx and the infiltration of immune cells in kidney tissue of HBV-Tg mice were observed by immunohistochemistry. Human podocyte cell line was transfected with pcDNA3.1/myc-HBx plasmid, and the localization of HBx and Nephrin in podocytes was detected by immunofluorescence. The expression of major histocompatibility complex Ⅱ (MHC-Ⅱ) and co- stimulatory molecule CD40 on the cell surface was detected by flow cytometry. The contents of multiple cytokines in cell culture supernatants were determined by enzyme-linked immunosorbent assay. Transcriptome sequencing (RNA-seq) was used to screen the downstream related genes regulated by HBx, and real-time quantitative PCR was used to verify their expressions. After overexpression or silencing of Notch1 gene with overexpressed plasmids or short hairpin RNA (shRNA) in podocytes, the effects on the expression of immune molecules and cytokines secretion was observed. The Notch receptor inhibitor N-[N-(3, 5-difluorophenyl-l- alanyl)]-(s)-phenylglycine tert-butyl ester (DAPT) was used to block Notch1 signaling pathway in HBV-Tg mice, and then blood biochemistry, renal pathological changes and infiltration of immune cells in kidney tissue were observed. Results:Twenty-four-hour urine protein, serum creatinine and urea nitrogen levels were markedly increased (all P<0.05) and renal pathological injury was significantly aggravated in HBV-Tg mice than those in WT mice. Also, HBx was up-regulated and immune cells infiltrated in the glomerulus of HBV-Tg mice. After transfection with HBx in podocytes, the expression of MHC-Ⅱ and CD40 on the cellular surface was up-regulated (all P<0.05), the contents of monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor -α (TNF-α) and interleukin (IL)-1β in the supernatants were increased (all P<0.05), and the secretion of IL-4 and interferon γ (IFN-γ) was unbalanced. RNA-seq screened downstream genes of HBx, such as Notch1, PLA2R, TLR4, etc; and further confirmed that HBx could promote the up-regulation of Notch1 mRNA and protein (all P<0.05). After over-expression of Notch1 gene, HBx-induced expression of MHC-Ⅱ and CD40 on the cellular surface was significantly up-regulated (all P<0.05), and the contents of MCP-1, TNF-α and IL-1β in the supernatants were obviously increased (all P<0.05), and the imbalance of IL-4/IFN-γ was further aggravated. After Notch1 gene silencing, the above results showed the opposite changes. In vivo, the results indicated that serum creatinine levels were obviously decreased (all P<0.05), renal pathological injury and immune cell infiltration were significantly alleviated in HBV-Tg+DAPT group than those in HBV-Tg+DMSO group. Conclusions:HBx protein can promote the up-regulation of Notch1 signaling pathway in podocytes. And Notch1 signaling pathway promotes the expression of immune molecules on the surface of podocytes and regulates the imbalance of cytokines, then causes glomerular injury and dysfunction of immune microenvironment.
