Fig. 3

Autophagy in human podocytes (HPCs). a, b Induction of autophagy in HPCs by immunoglobulin G (IgG) purified from lupus nephritis (LN) patients’ serum or a combination of IgG and vitamin D or vitamin D alone. Observation of autophagosomes under transmission electron microscope (TEM). Numbers of autophagosome in 30 random HPCs under TEM were counted. All statistical analyses were performed by using SPSS version 21.0 (SPSS Inc., Chicago, IL, USA) and GraphPad Prism 6 (GraphPad Software, Inc., La Jolla, CA, USA) for macOS. A P value of less than 0.05 was considered statistically significant. Data were expressed as mean ± standard deviation and median with range or frequency, as appropriate. Intergroup comparisons were made by using Pearson chi-squared test for categorical variables and Student’s t test, Mann–Whitney U test, or Wilcoxon test for continuous variables, as appropriate. *P <0.05 versus control (CON) group; ^#P <0.05 versus IgG group (n = 30). c Western blot analysis of LC3B, Beclin 1, p62, and nephrin expression in HPCs by IgG purified from serum from patients with LN or a combination of IgG and vitamin D or vitamin D alone. d Real-time polymerase chain reaction of MAP1LC3B, BECN1, and SQSTM1 gene expressions was analyzed (n = 4). *P <0.05 versus CON group; ^#P <0.05 versus IgG group. Abbreviation: VD vitamin D