Local NF-κB Activation Promotes Parathyroid Hormone Synthesis and Secretion in Uremic Patients

Abstract

Secondary hyperparathyroidism (SHPT) in uremic patients characterizes by parathyroid gland (PTG) hyperplasia and parathyroid hormone (PTH) elevation. Previously, we demonstrated that NF-κB activation contributed to parathyroid cell proliferation in chronic kidney disease (CKD) rats. Although vitamin D inhibits inflammation and ameliorates SHPT, the contribution of vitamin D deficiency to SHPT via local NF-κB activation remains to be clarified. PTGs collected from 10 uremic patients with advanced SHPT were used to test the expressions of vitamin D receptor (VDR), NF-κB, and proliferating cell nuclear antigen (PCNA). Freshly excised PTG tissues were incubated for 24 h in vitro with VDR activator (VDRA) calcitriol or NF-κB inhibitor Pyrrolidine Thiocarbamate (PDTC). Chromatin immunoprecipitation (ChIP) and luciferase reporter assays were performed to investigate the regulation of PTH transcription by NF-κB. We found higher levels of activated NF-κB and lower expression of VDR in nodular hyperplastic PTGs than in diffuse hyperplasia. In cultured PTG tissues, treatment with VDRA or PDTC inhibited NF-κB activation and PCNA expression, and downregulated preproPTH mRNA and intact PTH levels. ChIP assays demonstrated the presence of NF-κB binding sites in PTH promoter. Furthermore, in luciferase reporter assays, addition of exogenous p65 significantly increased PTH-luciferase activity by 2.4-fold (p<0.01), while mutation of NF-κB binding site at position –908 of the PTH promoter suppressed p65-induced PTH reporter activity (p<0.01). In summary, local NF-κB activation contributes to SHPT and mediates the transcriptional activation of PTH directly in uremic patients. Vitamin D deficiency may be involved in SHPT via the activation of NF-κB pathway.

Mechanism of calcitriol regulating parathyroid cells in secondary hyperparathyroidism

“…The measurement of p65 phosphorylation is the standard method for determining its level of activity ( Perkins, 2007 ). Mao J, et al first proof that NF-κB p65 directly promotes PTH expression via combined with the p65-responsive region, which is between positions -908 and -897 upstream of the PTH promoter ( Mao et al, 2021 ). The research prompts that activation of NF-κB pathway not only promotes the parathyroid proliferation, but also directly raises the transcription of PTH gene.…”

“…Similar regulation through 1,25(OH)2D3 may underlie the inhibition of parathyroid hyperplasia. However, in vitro treatment of PTGs with 1,25(OH)2D3, only a considerable suppression of phos-NF-κB and an elevation of IκBα concentration were seen ( Mao et al, 2021 ), suggesting that 1,25(OH)2D3 restrains the activation of NF-κB pathway by arresting p65 nuclear translocation, blocking NF-κB DNA binding, including PTH gene, increasing IκBα levels, or stabilizing IκBα protein in advanced SHPT of CKD. It is possible that the decreased number of VDR receptors in hyperplastic glands is partially to blame for the decreased inhibitory effect of 1,25(OH)2D3 on the NF-KB pathway.…”

Facile preparation of nitrogen/titanium-rich porous organic polymers for specific enrichment of N-glycopeptides and phosphopeptides

“…28–30 From the perspective of biological processes, thyroid hormone transport, acute inflammatory response, and negative regulation of proteolysis were significantly overexpressed. 31–33 In addition, Fig. S17† shows the analytical bar graphs of the captured phosphoproteins' molecular activities, biological processes, and cellular components.…”

Identification of key biomarkers based on the proliferation of secondary hyperparathyroidism by bioinformatics analysis and machine learning

“…The sections were stained using standard H&E and IHC protocols as previously described ( Kan et al, 2018 ). According to the characteristics of HE staining, the parathyroid glands of SHPT patients were divided into diffuse and nodular hyperplasia ( Mao et al, 2021 ). The primary antibodies used were CIDEA (1:100; Affinity, West Bridgford, UK), CAPZA1(1:50, Proteintech, Manchester, UK), and PCOLCE2 (1:100; Wuhan Fine Biotech, Hubei, China).…”