Journal: Journal of Advanced Research
Article Title: Podocyte TLR4 deletion alleviates diabetic kidney disease through prohibiting PKCδ/SHP-1-dependent ER stress and relieving podocyte damage and inflammation
doi: 10.1016/j.jare.2025.07.013
Figure Lengend Snippet: TLR4/MyD88/PKCδ/SHP-1 signaling-dependent ER stress stimulated MCP-1 production via enhanced transcription activity by ATF4 binding to its promoter in hyperglycemic podocytes. (A) The altered expression of MCP-1 in renal tissue from mice at 12 and 16 weeks by western blot. P values were determined by one-way ANOVA and data are presented as mean ± SD. **** P < 0.01; # P < 0.05; ## P < 0.01 ( n = 8 samples). (B) Representative western blot to assess the levels of MCP-1 in cultured mouse podocytes from treatments of LG or HG for 48 h with or without transfection of TLR4, MyD88 or scrambled shRNAs. P values were determined by one-way ANOVA and data are presented as mean ± SD. **** P < 0.01; ### P < 0.01 ( n = 3 independent experiments). (C) Representative western blot to show the expression of MCP-1 in podocytes after HG stimulation for 48 h with or without transfection of PKCδ, SHP-1 or scrambled shRNAs, or pretreatment of 4-PBA. P values were determined by one-way ANOVA and data are presented as mean ± SD. ** P < 0.01; *** P < 0.01; ### P < 0.01 ( n = 3 independent experiments). (DE) The expression of MCP-1 by western blot (D), and ER stress markers BIP, sXBP-1, ATF4 and ATF6 (E) after HG stimulation for 48 h with or without MCP-1 or scrambled shRNA transfection. P values were determined by one-way ANOVA and data are presented as mean ± SD. ## P < 0.01; #### P < 0.01 ( n = 3 independent experiments). (F) Schematic description of primers spanning the distal, medial, and proximal regions of the MCP-1 promoter, encompassing predicted binding sites in the present study. (GH) ChIP analysis using anti-ATF4 or anti-IgG antibodies were performed either in cultured mouse podocytes after LG or HG treatment for 48 h (G), or HG stimulation with transfection of TLR4, PKCδ, MCP-1 or scrambled shRNA, or pretreatment of 4-PBA (H). Real-time PCR was used for the detection of the ChIP signals. P values were determined by Student’s t -test, or by one-way ANOVA, and data are presented as mean ± SD. * P < 0.05; ** P < 0.01; **** P < 0.01; #### P < 0.01 ( n = 3 independent experiments). (I) Determination of ATF4 nuclear accumulation in podocytes under LG or HG conditions by western blot. P values were determined by Student’s t -test and data are presented as mean ± SD. ** P < 0.01; ## P < 0.01 ( n = 3 independent experiments). (J) Assessment of nuclear ATF4 protein levels in cultured podocytes transfected with TLR4, PKCδ, MCP-1 or scrambled shRNAs, or pretreated with 4-PBA under HG conditions for 48 h. P values were determined by one-way ANOVA and data are presented as mean ± SD. * P < 0.05; * P < 0.01 ( n = 3 independent experiments).
Article Snippet: The following primary antibodies were used: f4/80 (29414–1-AP), desmin (16520–1-AP), MCP-1 (26161–1-AP), podocin (20384–1-AP), synaptopodin (21064–1-AP), TLR4 (66350–1-Ig), β-actin (66009–1-Ig), PKCδ(14188–1-AP), ATF6 (24169–1-AP), p-cadherin (13773–1-AP) were from Proteintech (IL, USA); phospho-PKCδ (Y311) (ab76181), PKCdelta (ab182126), SHP-1 (ab227503), HA (ab9110) were from Abcam (MA, USA); BIP (M010300), MyD88 (P012343) were from Epizyme, Shanghai, China); and ATF4 (11815), sXBP-1 (40435) were from Cell Signaling Technology (MA, USA).
Techniques: Activity Assay, Binding Assay, Expressing, Western Blot, Cell Culture, Transfection, shRNA, Real-time Polymerase Chain Reaction