Comparative proteomic analysis of urine and laser microdissected glomeruli in IgA nephropathy.

The purpose of the present study was to identify the differential proteins that synchronously change in urine and glomeruli and could be used to monitor glomerular lesions of IgA nephropathy (IgAN). The proteomes of urine and glomeruli from four IgAN patients who were graded III/IV according to the grading system of Lee et al. were compared to the urine proteomes of four healthy volunteers and the glomeruli proteomes of adjacent normal tissue from four patients with renal tumors, respectively. Western blot, enzyme-linked immunosorbent assay and immunofluorescence assay were applied to verify the results of the proteomic analysis. In the proteomic analysis of urine from IgAN patients and healthy volunteers, 714 proteins were identified, with 246 proteins identified as differential proteins. In the proteomic analysis of glomeruli from renal biopsy tissue of IgAN patients and from adjacent normal tissue of patients with renal tumors, 161 proteins were identified altogether, and 20 proteins of these were recognized as differential proteins. After comparatively analyzing the differential proteins identified in the urine and glomeruli, five synchronously changed differential proteins were found: complement C9, Ig kappa chain C region and three cytoskeleton proteins. In summary, our findings indicate that certain immunological indices in urine appear to be associated with glomerular lesions of IgAN.

Baicalin Reduces Renal Inflammation in Mesangial Proliferative Glomerulonephritis through Activation of Nrf2/ARE and PI3K/AKT Pathways.

OBJECTIVE: Mesangial proliferative glomerulonephritis (MPGN) is a prevalent form of primary glomerulonephritis, distinguished by the proliferation of mesangial cells and the accompanying inflammatory response. Baicalin, the active ingredient in the Scutellaria baicalensis Georgi plant, has been observed to have a protective effect on the kidneys. However, its specific impact on MPGN has yet to be studied widely. Hence, this study aimed to investigate the effect on MPGN and the underlying mechanisms of Baicalin. METHODS: Thirty-six Sprague-Dawley (SD) rats, aged 6 to 8 weeks, were randomly allocated into different subgroups: control, model, benazepril, and three baicalin subgroups (low, medium, and high dose), each consisting of six rats. The concentrations of 24-hour urinary protein, blood urea nitrogen (BUN), serum creatinine (SCr), triglycerides (TG), total cholesterol (TC), interleukins (IL-1α, IL-2, IL-10), and interferon-γ (IFN-γ) were measured with biochemistry. The pathological alterations in the renal tissue were examined using Hematoxylin and Eosin (HE) along with Periodic Acid-Schiff (PAS) staining. Concurrently, the extent of apoptosis was evaluated using TdT-mediated dUTP nick end labeling (TUNEL) staining. In vitro, mesangial cells were exposed to 30 µg/mL lipopolysaccharide for 24 h, with or without varying concentrations of baicalin (10, 20, 40 µM). MTT assay was applied to estimate cell activity, flow cytometry to evaluate the cell cycle, and 5-ethynyl-2-deoxyuridine (EdU) detection to measure cell proliferation. IL-1α, IL-2, IL-10, and IFN-γ concentrations in the cell supernatant were assayed with biochemistry. Furthermore, the expression of apoptosis-related proteins, concluding BCL2-Associated X (Bax), Bcl-2, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), and caspase-1, NF-E2-related factor 2/antioxidant response element (Nrf2/ARE) pathway-related proteins (Nrf2 and HO-1), and phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT) pathway-related proteins (p-PI3K, PI3K, p-AKT, and AKT) in both the renal tissue and cell supernatant were measured. RESULTS: Baicalin treatment significantly reduced the 24-hour urinary protein, serum levels of BUN, SCr, TG, TC, IL-1α, IL-2, IL-10, and IFN-γ in vivo experiments. Baicalin treatment also improved the pathological condition of renal tissue and decreased the occurrence of apoptosis. In vitro, findings confirmed that baicalin inhabits the proliferation of mesangial cells triggered by Lipopolysaccharide (LPS), induces a G1 phase cell cycle arrest, and reduces the concentrations of IL-1α, IL-2, IL-10, and IFN-γ. Baicalin also decreased the ratios of p-PI3K/PI3K and p-AKT/AKT while enhancing the levels of Nrf2 and HO-1 in both renal tissue and cell supernatant. CONCLUSIONS: Baicalin can mitigate MPGN by impeding the proliferation and inflammation of mesangial cells by activating Nrf2/ARE and PI3K/AKT pathways.