Effects of HIF-1α, hepcidin and PTH on RankL in patients with chronic kidney disease in different stages.

OBJECTIVE: To investigate the effects of hypoxia-inducible factor-1α (HIF-1α), hepcidin, and parathyroid hormone (PTH) on the serum nuclear factor κB and receptor activating factor ligand (RankL) in patients with chronic kidney disease (CKD) stages 3-5. METHODS: A total of 90 patients admitted to our hospital's Department of Nephrology from March 2018 to December 2019 were randomly selected as the subjects (30 patients with CKD3, CKD4, and CKD5 each). A total of 30 healthy volunteers receiving a physical examination in our hospital during the same period were selected for the control group. Then, the participants' HIF-1α, hepcidin, and RankL levels were detected by double-antibody sandwiched enzyme-linked immunosorbent assay. The serum creatinine, serum iron, hemoglobin, and phosphorus (P3+) levels were determined by BeckMAN-c800 automatic biochemical analysis. The glomerular filtration rate (eGFR) was calculated by the CKD-EPI formula. RESULTS: (1) The levels of HIF-1α, RankL, hepcidin, and PTH were all elevated, and the serum ferritin and P3+ were elevated in each stage; (2) Linear correlation analysis: The HIF-1α and hepcidin showed a higher correlation with RankL in CKD3 and CKD4(CKD3: The correlation coefficient r = 0.558 between HIF-1α and RankL, and r = 0.604 between HEpcidin and RankL; CKD4: Correlation coefficient r = 0.840 between HIF-1α and RankL, and r = 0.753 between HEpcidin and RankL), while the PTH showed a higher correlation with RankL in CKD5 (correlation index r = 0.631). Multiple linear stepwise regression analysis: RankL was independently correlated with HIF-1α, hepcidin, and PTH. Regression coefficient B of HIF-1α was the highest in both CKD3 and CKD4. The coefficient B value of PTH in CKD5 was 3.971; HIF-1α and hepcidin were not included in the regression equation. CONCLUSION: The levels of RankL in both CKD3 and CKD4 were increased and mainly affected by HIF-1α, followed by hepcidin. Moreover, HIF-1α and PTH had a combined effect on the RankL level in CKD5, and PTH was the main influencing factor.

Identification of natural coumarin compounds that rescue defective DeltaF508-CFTR chloride channel gating.

1. Deletion of phenylalanine at position 508 (DeltaF508) of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is the most common mutation causing cystic fibrosis (CF). Effective pharmacological therapy of CF caused by the DeltaF508-CFTR mutation requires the rescue of both intracellular processing and channel gating defects. 2. We identified a class of natural coumarin compounds that can correct the defective DeltaF508-CFTR chloride channel gating by screening a collection of 386 single natural compounds from Chinese medicinal herbs. Screening was performed with an iodide influx assay in Fischer rat thyroid epithelial cells coexpressing DeltaF508-CFTR and an iodide-sensitive fluorescent indicator (YFP-H148Q/I152L). 3. Dose-dependent potentiation of defective DeltaF508-CFTR chloride channel gating by five coumarin compounds was demonstrated by the fluorescent iodide influx assay and confirmed by an Ussing chamber short-circuit current assay. Activation was fully abolished by the specific CFTR inhibitor CFTR(inh)-172. Two potent compounds, namely imperatorin and osthole, have activation K(d) values of approximately 10 micromol/L, as determined by the short-circuit current assay. The active coumarin compounds do not elevate intracellular cAMP levels. Activation of DeltaF508-CFTR by the coumarin compounds requires cAMP agonist, suggesting direct interaction with the mutant CFTR molecule. Kinetics analysis indicated rapid activation of DeltaF508-CFTR by the coumarin compounds, with half-maximal activation of < 5 min. The activating effect was fully reversed for all five active compounds 45 min after washout. 4. In conclusion, the natural coumarin DeltaF508-CFTR activators may represent a new class of natural lead compounds for the development of pharmacological therapies for CF caused by the DeltaF508 mutation.