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Fibrinogen links podocyte injury with Toll‐like receptor 4 and is associated with disease activity in FSGS patients
Author(s) -
Wang Hongtian,
Zheng Chunxia,
Xu Xiaodong,
Zhao Yue,
Lu Yinghui,
Liu Zhihong
Publication year - 2018
Publication title -
nephrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 61
eISSN - 1440-1797
pISSN - 1320-5358
DOI - 10.1111/nep.13046
Subject(s) - podocyte , tlr4 , medicine , nephrin , minimal change disease , podocin , toll like receptor , glomerulosclerosis , endocrinology , mapk/erk pathway , slit diaphragm , focal segmental glomerulosclerosis , receptor , cancer research , proteinuria , signal transduction , innate immune system , biology , microbiology and biotechnology , kidney
Aim Fibrinogen (Fg) is reported to participate in inflammation through Toll‐like receptor 4 (TLR4). However, it remains unknown whether Fg might induce podocyte damage through TLR4 and be related to disease activity in patients with focal segmental glomerulosclerosis (FSGS). Methods We observed Fg‐induced alterations in actin and apoptosis in cultured human podocytes transfected with or without TLR4 siRNA. Expression of TLR4, phospho‐p38 MAPK and phospho‐NF‐κB p65 was evaluated by quantitative reverse transcription polymerase chain reaction (qRT‐PCR) or western blotting, and we analysed urinary Fg levels in adriamycin‐treated mice and double immunofluorescence staining for TLR4, Fg and podocin. Urinary Fg changes were also analyzed in FSGS patients under prednisone treatment. Results First, Fg dose‐dependently induced actin damage and apoptosis in cultured human podocytes, with an Fg‐induced increase in TLR4 expression, and TLR4 siRNA transfection prevented these effects. TLR4 knockdown inhibited activation of p38 MAPK and NF‐κB p65 in podocytes. Elevated urinary Fg levels were positively correlated with albuminuria in adriamycin‐treated mice, in which Fg and TLR4 colocalized and exhibited increased expression in podocytes. Additionally, elevated urinary Fg levels were positively correlated with 24‐h proteinuria and foot process width in FSGS patients. Urinary Fg levels were significantly decreased in patients with complete remission but not in those without remission. Conclusions Fg induced podocytes injury via the TLR4‐p38 MAPK‐NF‐κB p65 pathway. In FSGS patients, urinary Fg levels reflect therapeutic response to prednisone and disease activity.