Impaired local Vitamin D3 metabolism contributes to IL-36g overproduction in epithelial cells in chronic rhinosinusitis with nasal polyps.

BACKGROUND: Vitamin D (VD) possesses immunomodulatory properties, but its role in chronic rhinosinusitis with nasal polyps (CRSwNP) remains poorly studied. Herein, we aim to explore the regulation and function of VD3 in CRSwNP. METHODS: 25-hydroxyvitamin D3 (25VD3) levels in serum and tissue lysates were detected by ELISA. The expression of VD receptor (VDR) and cytochrome P450 family 27 subfamily B member 1 (CYP27B1), the enzyme that converts 25VD3 to the active 1,25-hydroxyvitamin D3 (1,25VD3), and their expression regulation in human nasal epithelial cells (HNECs) were studied by RT-PCR, western blotting, immunofluorescence, and flow cytometry. RNA sequencing was performed to identify genes regulated by 1,25VD3 in HNECs. HNECs and polyp tissue explants were treated with 1,25VD3, 25VD3, and dexamethasone. RESULTS: 25VD3 levels in serum and nasal tissue lysates were decreased in patients with eosinophilic and noneosinophilic CRSwNP than control subjects. The expression of VDR and CYP27B1 were reduced in eosinophilic and noneosinophilic CRSwNP, particularly in nasal epithelial cells. VDR and CYP27B1 expression in HNECs were downregulated by interferon y and poly (I:C). Polyp-derived epithelial cells demonstrated an impaired ability to convert 25VD3 to 1,25VD3 than control tissues. 1,25VD3 and 25VD3 suppressed IL-36y production in HNECs and polyp tissues, and the effect of 25VD3 was abolished by siCYP27B1 treatment. Tissue 25VD3 levels negatively correlated with IL-36y expression and neutrophilic inflammation in CRSwNP. CONCLUSION: Reduced systemic 25VD3 level, local 1,25VD3 generation and VDR expression result in impaired VD3 signaling activation in nasal epithelial cells, thereby exaggerating IL-36y production and neutrophilic inflammation in CRSwNP.

Vitamin D and calcium co-therapy mitigates pre-established cadmium nephropathy by regulating renal calcium homeostatic molecules and improving anti-oxidative and anti-inflammatory activities in rat.

BACKGROUND: Cadmium (Cd) is a major environmental pollutant and chronic toxicity could induce nephropathy by increasing renal oxidative stress and inflammation. Although vitamin D (VD) and calcium (Ca) prophylactic treatments attenuated Cd-induced cell injury, none of the prior studies measure their renoprotective effects against pre-established Cd-nephropathy. AIMS: To measure the alleviating effects of VD and/or Ca single and dual therapies against pre-established nephrotoxicity induced by chronic Cd toxicity prior to treatment initiation. METHODS: Forty male adult rats were allocated into: negative controls (NC), positive controls (PC), Ca, VD and VC groups. The study lasted for eight weeks and all animals, except the NC, received CdCl2 in drinking water (44 mg/L) throughout the study. Ca (100 mg/kg) and/or VD (350 IU/kg) were given (five times/week) during the last four weeks to the designated groups. Subsequently, the expression of transforming growth factor-ß (TGF-ß1), inducible nitric oxide synthase (iNOS), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), VD synthesising (Cyp27b1) and catabolizing (Cyp24a1) enzymes with VD receptor (VDR) and binding protein (VDBP) was measured in renal tissues. Similarly, renal expression of Ca voltage-dependent channels (CaV1.1/CaV3.1), store-operated channels (RyR1/ITPR1), and binding proteins (CAM/CAMKIIA/S100A1/S100B) were measured. Serum markers of renal function alongside several markers of oxidative stress (MDA/H2O2/GSH/GPx/CAT) and inflammation (IL-6/TNF-α/IL-10) together with renal cell apoptosis and expression of caspase-3 were also measured. RESULTS: The PC group exhibited hypovitaminosis D, hypocalcaemia, hypercalciuria, proteinuria, reduced creatinine clearance, and increased renal apoptosis/necrosis with higher caspase-3 expression. Markers of renal tissue damage (TGF-ß1/iNOS/NGAL/KIM-1), oxidative stress (MDA/H2O2), and inflammation (TNF-α/IL-1ß/IL-6) increased, whilst the antioxidants (GSH/GPx/CAT) and IL-10 decreased, in the PC group. The PC renal tissues also showed abnormal expression of Cyp27b1, Cyp24a1, VDR, and VDBP, alongside Ca-membranous (CaV1.1/CaV3.1) and store-operated channels (RyR1/ITPR1) and cytosolic Ca-binding proteins (CAM/CAMKIIA/S100A1/S100B). Although VD was superior to Ca monotherapy, their combination revealed the best mitigation effects by attenuating serum and renal tissue Cd concentrations, inflammation and oxidative stress, alongside modulating the expression of VD/Ca-molecules. CONCLUSIONS: This study is the first to show improved alleviations against Cd-nephropathy by co-supplementing VD and Ca, possibly by better regulation of Ca-dependent anti-oxidative and anti-inflammatory actions.

Deferasirox and vitamin D3 co-therapy mitigates iron-induced renal injury by enhanced modulation of cellular anti-inflammatory, anti-oxidative stress, and iron regulatory pathways in rat.

BACKGROUND: Chronic iron overload could induce nephropathy via oxidative stress and inflammation, and chelating therapy has limited efficacy in removing excess intracellular iron. Although vitamin D (VD) has shown potent antioxidant and anti-inflammatory effects, as well contribute to iron homeostasis, none of the previous studies measured its potential remedial effects against chronic iron toxicity. AIMS: To measure the alleviating effects of deferasirox (DFX) and/or vitamin D (VD) single and combined therapies against nephrotoxicity induced by chronic iron overload. METHODS: Forty male rats were divided into negative (NC) and positive (PC) controls, DFX, VD, and DFX/VD groups. The designated groups received iron for six weeks followed by DFX and/or VD for another six weeks. Then, the expression pattern of renal genes and proteins including hepcidin, ferroportin (FPN), megalin, transferrin receptor 1 (TfR1), ferritin heavy and light chains, VD receptor (VDR), VD synthesizing (Cyp27b1) and catabolizing (Cyp24a1) enzymes were measured alongside serum markers of renal function and iron biochemical parameters. Additionally, several markers of oxidative stress (MDA/H2O2/GSH/SOD1/CAT/GPx4) and inflammation (IL-1ß/IL-6/TNF-α/IL-10) together with renal cell apoptosis and expression of caspase-3 (Casp-3) were measured. RESULTS: The PC rats showed pathological iron and renal biochemical markers, hypovitaminosis D, increased renal tissue iron contents with increased Cyp24a1/Megalin/ferritin-chains/hepcidin, and decreased Cyp27b1/VDR/TfR1/FPN expression than the NC group. The PC renal tissues also showed abnormal histology, increased inflammatory (IL-1ß/IL-6/TNF-α), oxidative stress (MDA/H2O2), and apoptosis markers with decreased IL-10/GSH/SOD1/CAT/GPx4. Although DFX monotherapy reduced serum iron levels, it was comparable to the PC group in renal iron concentrations, VD and iron-homeostatic molecules, alongside markers of oxidative stress, inflammation, and apoptosis. On the other hand, VD monotherapy markedly modulated renal iron and VD-related molecules, reduced renal tissue iron concentrations, and preserved renal tissue relative to the PC and DFX groups. However, serum iron levels were equal in the VD and PC groups. In contrast, the best significant improvements in serum and renal iron levels, expression of renal iron-homeostatic molecules, oxidative stress, inflammation, and apoptosis were seen in the co-therapy group. CONCLUSIONS: iron-induced nephrotoxicity was associated with dysregulations in renal VD-system together with renal oxidative stress, inflammation, and apoptosis. While DFX reduced systemic iron, VD monotherapy showed better attenuation of renal iron concentrations and tissue damage. Nonetheless, the co-therapy approach exhibited the maximal remedial effects, possibly by enhanced modulation of renal iron-homeostatic molecules alongside reducing systemic iron levels. AVAILABILITY OF DATA AND MATERIALS: All data generated or analysed during this study are included in this published article [and its Supplementary information files].

Calcitriol increases nitric oxide production and modulates microbicidal capacity against Mycobacterium bovis in bovine macrophages.

Bovine tuberculosis, a re-emerging infectious disease caused by Mycobacterium bovis, can be transmitted to humans. Global prevalence of M. bovis in humans is underestimated and represents a serious public health risk in developing countries. In light of this situation, it is important to note that our understanding of the immunopathogenesis of human tuberculosis can be improved by studying this disease in the bovine model. Stimulation of the bovine innate immune system with calcitriol (1,25(OH)2D3) leads to an increase in bactericidal molecules involved in macrophage antimicrobial activity. It is unknown, however, if calcitriol´s effect on bovine macrophages impacts intracellular bacterial replication. With these considerations in mind, this study sought to investigate the specific role of calcitriol in tuberculosis control in bovine macrophages, in the hopes of uncovering information applicable to human tuberculosis. As such, infection with M. bovis was shown to induce expression of CYP27B1 and VDR genes in macrophages. Moreover, addition of 1,25(OH)2D3 to cultures of macrophages previously infected with mycobacteria and/or activated by LPS triggered cellular expression of nitric oxide synthase (NOS2) and increased nitrite concentrations, both indicators of nitric oxide (NO) production. By means of a microbicidal assay, addition of 1,25(OH)2D3 was seen to increase macrophage phagocytosis and to decrease mycobacterial intracellular replication. Thus, taken together, our results show that calcitriol can help stimulate the innate immune system of bovines by increasing phagocytosis and decreasing intracellular replication of microorganisms, such as M. bovis, in macrophages, through the VDR pathway.