The role of complement (C) in the pathogenesis or progression of focal segmental glomerulosclerosis (FSGS) is uncertain. The present study assessed the relationship between serum C3, the baseline characteristics, and the progression of FSGS in the cohort and identified the clinical implications of serum C3 levels in patients with FSGS. Compared to the patients with C3 ≥ 85 mg/dL (N = 474), those with C3 < 85 mg/dL (N = 117) presented a higher level of serum creatinine, lower levels of eGFR, hemoglobin, proteinuria, triglyceride, cholesterol, IgA, as well as, severe tubulointerstitial injury (TI). Of the 221 patients with a mean follow-up of 53.3 months, the risk of reaching end-stage renal disease (ESRD) was significantly higher in patients with low serum C3 level (p < 0.001). An additional 40 patients with primary FSGS revealed a significant correlation between MAC and AP (p = 0.003), MAC and serum C3 (p = 0.018), and AP and serum C3 (p = 0.028). Compared to patients with none-to-mild TI, those with moderate-to-severe TI exhibited a lower level of serum C3 and AP, and a higher level of serum MAC. In conclusion, complement activation occurring in patients with FSGS is associated with clinical and histological severities. Low serum C3 was an independent risk factor for poor renal outcome in patients with FSGS.

Here, we report a genetic study of an extended family of Chinese ancestry with focal segmental glomerulosclerosis (FSGS), with one of the affected members also concurrently diagnosed with IgA nephropathy (IgAN). By genome-wide linkage analysis and subsequent sequencing, we identified an S85W mutation in the inverted formin 2 (INF2) gene that perfectly cosegregated with the kidney disease phenotype. The entire INF2 coding region was sequenced in 200 healthy controls, 55 families with FSGS, and 34 families with IgAN. This analysis identified a novel insertion, S129_Q130insVRQLS, in another FSGS pedigree. In vitro studies found that α-actinin 4 expression was decreased and INF2 showed perinuclear localization in S85W-transfected podocytes. Phosphorylation of serum response factor, and that its nuclear translation was decreased in S85W podocytes, indicated decreased activation in mutants. Abnormal actin organization was also found in S85W podocytes, while no change of microtubule structure was observed. Co-immunoprecipitation and immunofluorescence found decreased interaction between INF2 and Cdc42 in S85W podocytes. However, all these changes were not found in S129_Q130insVRQLS podocytes. The overall frequency of INF2 mutations was ~3.6% among Chinese familial FSGS, which was considerably lower than that from studies of European FSGS families. Thus, S85W but not the S129_Q130insVRQLS variant leads to podocyte cytoskeletal abnormalities, probably by impaired serum response factor phosphorylation.

To search for biomarkers to differentiate primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD).

Glucocorticosteroid is used for patients with primary nephrotic syndrome. This study aims to identify and validate that biomarkers can be used to predict steroid resistance.

There is currently a lack of studies investigating long-term prognosis and the necessity of further rituximab (RTX) consolidation treatment for minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). The aim of this study was to evaluate the efficacy of RTX for these diseases and to investigate whether a consolidation treatment can lower risks of relapse and reinforce long-term remission.

Podocytes are terminally differentiated epithelial cells in the kidney glomeruli that act as a key component of the glomerular filtration barrier. Although the inciting injury to the podocyte may vary between various glomerular diseases, the inevitable consequence of podocyte injury results in their loss, leading to progressive kidney disease. Here, we report that the expression of CCAAT/enhancer binding protein-α (C/EBP-α), a transcription factor known to interact with and activate PPAR-γ and NF-κB, is suppressed in the glomerular cells, particularly in podocytes, in human kidneys with focal segmental glomerulosclerosis. Genetic ablation of C/EBP-α in podocytes resulted in increased proteinuria, increased podocyte foot process effacement, and to decreased podocyte number in the setting of Adriamycin (ADR)-induced nephropathy. Overexpression of C/EBP-α in human podocytes in vitro led to an inhibition of MCP-1 and IL-6 expression in response to TNF-α and IL-1β treatments. Conversely, augmented production of MCP-1 and IL-6 was observed in the glomeruli of C/EBP-α knockout mice and was associated increased infiltration of macrophages in vivo. Together, our data suggest that C/EBP-α mediates anti-inflammatory effects in podocytes to confer protection against podocyte injury and loss that may contribute to worsening glomerulosclerosis.