Dioscin Mediated IgA Nephropathy Alleviation by Inhibiting B Cell Activation In Vivo and Decreasing Galactose-Deficient IgA1 Production In Vitro.

The increase of circulating galactose-deficient IgA1 (Gd-IgA1) is caused by excessive activation of IgA-positive secretory cells in the process of mucosal immune responses, which is a critical link in the pathogenesis of IgA nephropathy (IgAN). Peyer's patch, the prominent place where B lymphocytes are transformed into IgA-secreting plasma cells, is the primary source of IgA. In addition, the lower expression of core 1ß-1,3-galactosyltransferase (C1GalT1) and its molecular chaperone, C1GalT1-specific molecular chaperone (Cosmc), is related to abnormal glycosylation of IgA1 in IgAN patients. Our clinical experience shows that Dioscoreae Nipponicae Rhizoma's (DNR) herbal medicine can relieve proteinuria and hematuria and improve renal function in IgAN patients. Dioscin (DIO) is one of the main active ingredients of DNR, which has various pharmacological activities. This study explores DIO's possible mechanism in treating IgAN.The IgAN model mouse was established by mucosal immune induction. The mice were divided into the control, model, and DIO gavage groups. The glomerular IgA deposition in mice, renal pathological changes, and B cell markers CD20 and CXCR5 expression in Peyer's patch were detected by immunofluorescence and immunohistochemistry. After lipopolysaccharide (LPS) stimulation, DIO's effects on DAKIKI cells proliferation, IgA and Gd-IgA1 secretion, C1GalT1, and Cosmc expression were studied by cell counting kit-8 (CCK-8) assay, enzyme-linked immunosorbent assay (ELISA) test, quantitative real-time polymerase chain reaction (QRT-PCR), and western blotting (WB). In in vivo studies, IgA deposition accompanied by glomerular mesangial hyperplasia and increased expression of CD20 and CXCR5 in Peyer's patch in the IgAN model mouse was alleviated by DIO. In vitro studies showed 0.25 µg/mL to 1.0 µg/mL DIO inhibited LPS-induced DAKIKI cell proliferation, IgA and Gd-IgA1 secretion, and up-regulated the mRNA and protein expression of C1GalT1 and Cosmc. This study demonstrates that DIO may reduce Gd-IgA1 production by inhibiting excessive activation of IgA-secreting cells and up-regulating C1GALT1/Cosmc expression.

Seasonal changes in NRF2 antioxidant pathway regulates winter depression-like behavior.

Seasonal changes in the environment lead to depression-like behaviors in humans and animals. The underlying mechanisms, however, are unknown. We observed decreased sociability and increased anxiety-like behavior in medaka fish exposed to winter-like conditions. Whole brain metabolomic analysis revealed seasonal changes in 68 metabolites, including neurotransmitters and antioxidants associated with depression. Transcriptome analysis identified 3,306 differentially expressed transcripts, including inflammatory markers, melanopsins, and circadian clock genes. Further analyses revealed seasonal changes in multiple signaling pathways implicated in depression, including the nuclear factor erythroid-derived 2-like 2 (NRF2) antioxidant pathway. A broad-spectrum chemical screen revealed that celastrol (a traditional Chinese medicine) uniquely reversed winter behavior. NRF2 is a celastrol target expressed in the habenula (HB), known to play a critical role in the pathophysiology of depression. Another NRF2 chemical activator phenocopied these effects, and an NRF2 mutant showed decreased sociability. Our study provides important insights into winter depression and offers potential therapeutic targets involving NRF2.