Vitamin D3 pretreatment regulates renal inflammatory responses during lipopolysaccharide-induced acute kidney injury

VDR Activation Attenuates Renal Tubular Epithelial Cell Ferroptosis by Regulating Nrf2/HO-1 Signaling Pathway in Diabetic Nephropathy

Diabetic nephropathy (DN) is a serious microvascular complication of diabetes. Ferroptosis, a new form of cell death, plays a crucial role in the pathogenesis of DN. Renal tubular injury triggered by ferroptosis might be essential in this process. Numerous studies demonstrate that the vitamin D receptor (VDR) exerts beneficial effects by suppressing ferroptosis. However, the underlying mechanism has not been fully elucidated. Thus, they verified the nephroprotective effect of VDR activation and explored the mechanism by which VDR activation suppressed ferroptosis in db/db mice and high glucose-cultured proximal tubular epithelial cells (PTECs). Paricalcitol (PAR) is a VDR agonist that can mitigate kidney injury and prevent renal dysfunction. PAR treatment could inhibit ferroptosis of PTECs through decreasing iron content, increasing glutathione (GSH) levels, reducing malondialdehyde (MDA) generation, decreasing the expression of positive ferroptosis mediator transferrin receptor 1 (TFR-1), and enhancing the expression of negative ferroptosis mediators including ferritin heavy chain (FTH-1), glutathione peroxidase 4 (GPX4), and cystine/glutamate antiporter solute carrier family 7 member 11 (SLC7A11). Mechanistically, VDR activation upregulated the NFE2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathway to suppress ferroptosis in PTECs. These findings suggested that VDR activation inhibited ferroptosis of PTECs in DN via modulating the Nrf2/HO-1 signaling pathway.

Quinacrine, a PLA2 inhibitor, alleviates LPS-induced acute kidney injury in rats: Involvement of TLR4/NF-κB/TNF α-mediated signaling

Acute Kidney Injury (AKI) is a major factor in sepsis-related mortality and may occur due to lipopolysaccharide (LPS), an endotoxin produced by gram-negative bacteria that triggers a systemic acute inflammatory response. Quinacrine's (QC) renoprotective properties in sepsis and the underlying mechanism, however, are still not fully understood. This study was done to investigate the anti-inflammatory, antioxidative, and anti-apoptotic effects of QC, a phospholipase A2 (PLA2) inhibitor, against LPS-induced AKI. Rats were randomly divided into five groups: control group, QC30 group, LPS group, LPS+QC 10 group, and LPS+QC 30 group. The rats were administered intraperitoneally QC (10 and 30 mg/kg) for 3 days (once a day) prior to injection of LPS (3 mg/kg). Six hours after the LPS injection, the histopathological changes, oxidative stress, inflammation, and apoptosis in the collected kidney tissues were detected by hematoxylin and eosin staining, enzyme-linked immunosorbent assay (ELISA), real-time PCR (RT-PCR), and immunohistochemistry staining, respectively. QC pretreatment could successfully attenuate LPS-induced AKI, as evidenced by a decrease in tissue histopathological injury. Meanwhile, QC alleviated LPS-induced kidney oxidative stress; it reduced MDA levels and increased levels of SOD, CAT, GPX, and GSH. LPS-induced elevations in kidney TLR4, NF-κB, TNF-α, IL-1β, IL-6, PLA2, caspase 3, and Bax contents were significantly attenuated in QC-treated groups. Our findings revealed a significant effect of QC: protecting against LPS-induced AKI through inhibition of PLA2 and decreasing inflammation, oxidative stress, and apoptosis. To treat LPS-induced AKI, QC may be an effective substance with an excellent protection profile.

Macrophage angiotensin AT2 receptor activation is protective against early phases of LPS-induced acute kidney injury

Lipopolysaccharide (LPS)-induced acute kidney injury (AKI) is characterized by inflammation and infiltration of immune cells, mainly neutrophils and macrophages, and results in sudden renal dysfunction. Previously, we have reported the anti-inflammatory and renoprotective role of the angiotensin II type 2 receptor (AT2R), expressed on kidney tubular cells and immune cells, in LPS-induced AKI. Moreover, in vitro studies revealed macrophage AT2R activation shifts the cells to the anti-inflammatory M2 subtype. However, the protective role of the macrophage AT2R in a model of AKI is unknown. The present study addressed this question by adoptive transfer of bone marrow-derived macrophages (BMDMs) in systemic macrophage-depleted mice. We acquired significant systemic macrophage depletion by two doses of liposomal clodronate (CLD), and the mice were repopulated with BMDMs (CD11b+F4/80+, double positive) primed with AT2R agonist C21 (CLD + MacC21 + LPS) or vehicle (CLD + Mac + LPS) in vitro for 60 min, followed by LPS (5 mg/kg body wt ip) challenge. We observed a gradual increase in the CD11b+ cells at 2 and 24 h after the LPS challenge. However, kidney CD11b+ cells in the CLD + Mac + LPS group were elevated compared with the CLD + MacC21 + LPS group at 2 h after the LPS challenge. The level of inflammatory cytokine (tumor necrosis factor-α) was elevated at 2 h, which was reduced significantly in CLD + MacC21 + LPS-treated animals. Also, CLD + MacC21 + LPS-treated animals had elevated plasma and renal IL-10, indicating an anti-inflammatory role of C21-treated BMDMs. Renal functional injury in CLD + MacC21 + LPS-treated animals was partially improved. Collectively, the data demonstrate that BMDM AT2R stimulation results in anti-inflammation and partial renoprotection against early stages of LPS-induced AKI.NEW & NOTEWORTHY Endotoxin such as lipopolysaccharide (LPS) induces acute kidney injury (AKI), which is a risk factor for and often leads to chronic kidney diseases. The present study revealed that bone marrow-derived macrophage activation of the angiotensin II type 2 receptor (AT2R) contributes to the anti-inflammation and partial renoprotection against early stages of LPS-induced AKI. Since AT2R is an emerging anti-inflammatory and organ-protective target, this study advances our understanding of AT2R's anti-inflammatory mechanisms associated with renoprotection.

Melatonin alleviates intrarenal CaOx crystals deposition through inhibiting LPS-induced non-canonical inflammasome-mediated renal tubular epithelial cells pyroptosis

Urinary tract infection has long been considered a complication rather than etiology of calcium oxalate (CaOx) nephrolithiasis. This study aimed to explore the role of lipopolysaccharide (LPS), an important component of Gram-negative bacteria, on CaOx nephrolithiasis formation and antagonistic effect of melatonin. Male C57BL/6 mice were intraperitoneally injected with glyoxylate acid (80 mg/kg) daily for 7 days to construct CaOx nephrolithiasis model. A single dose of LPS (2.0 mg/kg) was given 2 h before the second glyoxylate acid treatment in the presence or absence of melatonin (25 mg/kg). Our results found that LPS promoted adhesion of CaOx crystals to renal tubular epithelial cells (RTECs) and intrarenal CaOx crystals deposition. Protein levels of cleaved Caspase-11, N-terminal of cleaved GSDMD (GSDMD-N), NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and cleaved Caspase-1, several markers of non-classical inflammasome activation were upregulated in LPS-treated mouse kidneys and HK-2 cells. Moreover, the number of GSDMD pores was increased in LPS-treated HK-2 cell membrane. Melatonin inhibited Caspase-11 cleavage and antagonized the subsequent LPS-mediated upregulation of GSDMD-N, NLRP3 and cleaved Caspase-1 in kidney tissues and HK-2 cells. In addition, melatonin reduced membrane localization of GSDMD-N and the number of GSDMD pores in LPS-treated HK-2 cells. Accordingly, melatonin inhibited LPS-induced IL-1β and IL-18 in mouse serum and HK-2 culture supernatant. Importantly, melatonin alleviated LPS-induced crystal-cell interactions and intrarenal CaOx crystals deposition. We provide experimental evidence that LPS promoted CaOx nephrolithiasis formation by inducing non-canonical inflammasome-mediated RTECs pyroptosis. Melatonin alleviated CaOx nephrolithiasis formation through inhibiting LPS-induced non-canonical inflammasome-mediated RTECs pyroptosis.

1,25(OH)2D3 promotes the elimination of Klebsiella pneumoniae infection by inducing autophagy through the VDR-ATG16L1 pathway

OBJECTIVE

Previous studies have shown that vitamin D has regulatory functions in both innate and adaptive immune responses, indicating that it can perform essential roles in host resistance to pathogen infections. This study aimed to verify its effects on Klebsiella pneumoniae (Kp) infection and explore the underlying mechanisms.

METHODS

THP-1-derived macrophages were infected with Kp and then incubated with 1,25(OH)₂D₃. Autophagy induced by 1,25(OH)₂D₃ was investigated by western blotting and immunofluorescence. Real-time PCR (qPCR) was performed to determine the expression of inflammatory mediators. Baf A1 and 3-MA were used to inhibit autophagy. The intracellular killing of Kp was measured using qPCR and colony-forming unit assays. RNA interference assays were used to silence VDR or ATG16L1. The lungs of C57BL/6 mice were infected with Kp via intratracheal instillation, and the established pneumonia models were used for in vivo validation experiments.

RESULTS

Treatment with 1,25(OH)₂D₃ enhanced the bactericidal activity of macrophages and concomitantly reduced the expression of the pro-inflammatory mediators TNF-α and IL-6. Kp infection led to a lower expression level of VDR in macrophages than in the control, whereas co-treatment with 1,25(OH)₂D₃ up-regulated VDR expression and robustly induced autophagy via the VDR signaling pathway. Silencing ATG16L1 significantly counteracted autophagy induced by 1,25(OH)₂D₃ in Kp-infected macrophages. Furthermore, we found that when autophagy activity was diminished by ATG16L1 siRNA or blocked by Baf A1, the ability of 1,25(OH)₂D₃ to promote macrophages to eliminate Kp infection was obviously impaired, as were its anti-inflammatory effects. These protective efficacies of 1,25(OH)₂D₃ against Kp infection were also validated in vivo using a mouse model of pneumonia.

CONCLUSIONS

The present study demonstrated the protective features of 1,25(OH)₂D₃ in macrophages against Kp infection and may provide evidence for further exploration of its potential as an adjunctive therapy agent for the treatment of bacterial infections.

Exposure to airborne particulate matter induces renal tubular cell injury in vitro: the role of vitamin D signaling and renin-angiotensin system

Background

Exposure to air pollution can interfere with the vitamin D endocrine system. This study investigated the effects of airborne particulate matter (PM) on renal tubular cell injury in vitro and explored the underlying mechanisms.

Methods

HK-2 human renal proximal tubule cells were treated with PM with or without 1,25(OH)₂D₃ analog, 19-Nor-1,25(OH)₂D₂ (paricalcitol, 10 nM) for 48 h. The dose- and time-dependent cytotoxicity of PM with or without paricalcitol was determined via cell counting kit-8 assay. Cellular oxidative stress was assessed using commercially available enzyme-linked immunosorbent assay kits. The protein expression of vitamin D receptor (VDR), cytochrome P450(CYP)27B1, CYP24A1, renin, angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AT1), nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor-kB (NF-kB), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 was determined.

Results

PM exposure decreased HK-2 cell viability in a dose- and time-dependent manner. The activities of superoxide dismutase and malondialdehyde in HK-2 cells increased significantly in the group exposed to PM. PM exposure decreased VDR and Nrf2, while increasing CYP27B1, renin, ACE, AT1, NF-kB, TNF-α, and IL-6. The expression of VDR, CYP27B1, renin, ACE, AT1, and TNF-α was reversed by paricalcitol treatment. Paricalcitol also restored the cell viability of PM-exposed HK-2 cells.

Conclusion

Our findings indicate that exposure to PM induces renal proximal tubular cell injury, concomitant with alteration of vitamin D endocrine system and renin angiotensin system. Vitamin D could attenuate renal tubular cell damage following PM exposure by suppressing the renin-angiotensin system and by partially inhibiting the inflammatory response.

The Role of Vitamin D in SARS-CoV-2 Infection and Acute Kidney Injury

Vitamin D has been described as an essential nutrient and hormone, which can cause nuclear, non-genomic, and mitochondrial effects. Vitamin D not only controls the transcription of thousands of genes, directly or indirectly through the modulation of calcium fluxes, but it also influences the cell metabolism and maintenance specific nuclear programs. Given its broad spectrum of activity and multiple molecular targets, a deficiency of vitamin D can be involved in many pathologies. Vitamin D deficiency also influences mortality and multiple outcomes in chronic kidney disease (CKD). Active and native vitamin D serum levels are also decreased in critically ill patients and are associated with acute kidney injury (AKI) and in-hospital mortality. In addition to regulating calcium and phosphate homeostasis, vitamin D-related mechanisms regulate adaptive and innate immunity. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have a role in excessive proinflammatory cell recruitment and cytokine release, which contribute to alveolar and full-body endothelial damage. AKI is one of the most common extrapulmonary manifestations of severe coronavirus disease 2019 (COVID-19). There are also some correlations between the vitamin D level and COVID-19 severity via several pathways. Proper vitamin D supplementation may be an attractive therapeutic strategy for AKI and has the benefits of low cost and low risk of toxicity and side effects.

Right Anterior Theta Hypersynchrony as a Quantitative Measure Associated with Autistic Traits and K-Cl Cotransporter KCC2 Polymorphism

Our aim was to use theta coherence as a quantitative trait to investigate the relation of the polymorphisms in NKCC1 (rs3087889) and KCC2 (rs9074) channel protein genes to autistic traits (AQ) in neurotypicals. Coherence values for candidate connection regions were calculated from eyes-closed resting EEGs in two independent groups. Hypersynchrony within the right anterior region was related to AQ in both groups (p < 0.05), and variability in this hypersynchrony was related to the rs9074 polymorphism in the total group (p < 0.05). In conclusion, theta hypersynchrony within the right anterior region during eyes-closed rest can be considered a quantitative measure for autistic traits. Replicating our findings in two independent populations with different backgrounds strengthens the validity of the current study.

Single Treatment of Vitamin D3 Ameliorates LPS-Induced Acute Lung Injury through Changing Lung Rodentibacter abundance

Acute lung injury (ALI) is characterized by severe inflammation. Vitamin D3 is discussed to reduce inflammation in ALI, but the mechanism is not well understood. This study assesses the effect of different calcitriol administration strategies on inflammation and the lung microbiota composition in ALI. In a mouse model, the alveolus and airway pathology are assessed by immunohistology. mRNA expression is determined by Real-Time Quantitative PCR and protein expressions is detected by Western-blotting. The composition of microbiota is performed by 16s DNA high-throughput sequencing. Short-term vitamin D3 supplementation prevents lipopolysaccharide-induced ALI by preventing pro-inflammatory cytokines including interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). In contrast, long-term treatment over 3 days, 6 days, or 10 days had no such effect. Short-term vitamin D3, but not long-term pretreatment significantly reduces the phosphorylation of signal transducer and activator of transcription 3 and suppressor of cytokine signaling 3, but upregulates the phosphorylation of inhibitor of nuclear factor-κ-gene binding. Furthermore, an increased relative abundance of Rodentibacter genus in LPS-challenged mice bronchoalveolar lavage fluid is observed, which is sensitive to short-term vitamin D3 treatment, effectively alleviating the Rodentibacter abundance. Correlation analysis shows that the load of Rodentibacter positively correlated with the IL-1β, IL-6, and TNF-α gene expression. The data support that a single administration of vitamin D3 may work as an adjuvant therapy for acute lung inflammation.

Vitamin D decreases pancreatic iron overload in type 2 diabetes through the NF-κB-DMT1 pathway

Emerging evidence has deemed vitamin D as a potential candidate for the intervention of type 2 diabetes (T2D). Herein, we explored the underlying mechanisms of T2D prevention by vitamin D, concentrating on pancreatic iron deposition reported recently. Zucker diabetic fatty (ZDF) rats were treated by vitamin D, with age-matched Zucker lean rats as control. As expected, vitamin D treatment for ZDF rats normalized islet morphology and β-cell function. Moreover, vitamin D alleviated iron accumulation and apoptosis in pancreatic cells of ZDF rats, accompanied by lowered divalent metal transporter 1 (DMT1) expression. Consistently, similar results were observed in high glucose-stimulated INS-1 cells treated with or without vitamin D. Nuclear factor-κB (NF-κB), a transcription factor involving DMT1 regulation, was activated in pancreases of ZDF rats and INS-1 cells exposed to high glucose, but inactivated by vitamin D or BAY 11-7082, a NF-κB inhibitor. Futhermore, IL-1β functioning as NF-κB activator abolished the suppression of NF-κB activation, DMT1 induction and the attenuation of apoptosis as a consequence of vitamin D incubation. Our study showed that iron overload in pancreas may contribute to T2D pathogenesis and uncovered a potentially protective role for vitamin D on iron deposition of diabetic pancreas through NF-κB- DMT1 signaling.

Vitamin D suppresses bleomycin-induced pulmonary fibrosis by targeting the local renin-angiotensin system in the lung

Idiopathic pulmonary fibrosis (IPF) is a severe disorder leading to progressive and irreversible loss of pulmonary function. In this study we investigated the anti-fibrotic effect of vitamin D using a mouse model of IPF. Lung fibrosis was induced with bleomycin in vitamin D-sufficient and vitamin D-deficient C57BL/6 mice. We found that treatment with active vitamin D analog paricalcitol prevented mouse body weight loss and alleviated lung fibrosis, whereas vitamin D deficiency severely aggravated lung injury. At the molecular level, paricalcitol treatment suppressed the induction of fibrotic inducer TGF-β and extracellular matrix proteins α-SMA, collagen type I and fibronectin in the lung, whereas vitamin D deficiency exacerbated the induction of these proteins. Interestingly, bleomycin treatment activated the local renin–angiotensin system (RAS) in the lung, manifested by the induction of renin, angiotensinogen, angiotensin II and angiotensin receptor type 1 (AT1R). Paricalcitol treatment suppressed the induction of these RAS components, whereas vitamin D deficiency enhanced the activation of the lung RAS. We also showed that treatment of bleomycin-induced vitamin D-deficient mice with AT1R antagonist losartan relieved weight loss, substantially ameliorated lung fibrosis and markedly blocked TGF-β induction in the lung. Moreover, we demonstrated that in lung fibroblast cultures, TGF-β and angiotensin II synergistically induced TGF-β, AT1R, α-SMA, collagen type I and fibronectin, whereas 1,25-dihydroxyvitamin D markedly suppressed the induction of these fibrotic markers. Collectively, these observations strongly suggest that vitamin D mitigates lung fibrosis by blocking the activation of the lung RAS in this mouse model of IPF.

Vitamin D/VDR in Acute Kidney Injury: A Potential Therapeutic Target

Despite many strategies and parameters used in clinical practice, the incidence and mortality of acute kidney injury (AKI) are still high with poor prognosis. With the development of molecular biology, the role of vitamin D and vitamin D receptor (VDR) in AKI is drawing increasing attention. Accumulated researches have suggested that Vitamin D deficiency is a risk factor of both clinical and experimental AKI, and vitamin D/VDR could be a promising therapeutic target against AKI. However, more qualitative clinical researches are needed to provide stronger evidence for the clinical application of vitamin D and VDR agonists in the future. Issues like the route and dosage of administration also await more attention. The present review aims to summarize the current works on the role of vitamin D/VDR in AKI and provides some new insight on its therapeutic potential.

Lung-Centric Inflammation of COVID-19: Potential Modulation by Vitamin D

SARS-CoV-2 infects the respiratory tract and leads to the disease entity, COVID-19. Accordingly, the lungs bear the greatest pathologic burden with the major cause of death being respiratory failure. However, organs remote from the initial site of infection (e.g., kidney, heart) are not spared, particularly in severe and fatal cases. Emerging evidence indicates that an excessive inflammatory response coupled with a diminished antiviral defense is pivotal in the initiation and development of COVID-19. A common finding in autopsy specimens is the presence of thrombi in the lungs as well as remote organs, indicative of immunothrombosis. Herein, the role of SARS-CoV-2 in lung inflammation and associated sequelae are reviewed with an emphasis on immunothrombosis. In as much as vitamin D is touted as a supplement to conventional therapies of COVID-19, the impact of this vitamin at various junctures of COVID-19 pathogenesis is also addressed.

High-dose vitamin D3 supplementation ameliorates renal fibrosis by vitamin D receptor activation and inhibiting TGF-β1/Smad3 signaling pathway in 5/6 nephrectomized rats

Renal fibrosis is the pathological consequence of progressive chronic kidney disease. Although it has been reported that vitamin D3 exerts antifibrotic effects, the underlying mechanisms remain unclear. This study is aimed at investigating the effects and molecular mechanisms in high-dose vitamin D3 treatment on renal fibrosis. A model of chronic kidney disease was established by 5/6 nephrectomy in rats characterised by high levels of serum creatine, urea nitrogen, and urinary protein. Serum 25-dihydroxyvitamin D3, calcium and parathormone levels were measured to evaluate vitamin D levels. Hematoxylin and eosin, periodic acid Schiff and Mallory's Trichrome staining were used to evaluate histopathological changes in rats. Moreover, the expression of vimentin, collagen I, α-smooth muscle actin and E-cadherin were analyzed at molecular and histopathological levels. Our results showed that exposure to vitamin D3 decreased the levels of serum creatine, urea nitrogen and urine protein and restored the homeostasis of calcium and parathormone. Vitamin D3 also downregulated the expression of vimentin, collagen I and α-smooth muscle actin and attenuated renal fibrosis and epithelial to mesenchymal transition in the kidney. Importantly, vitamin D3 treatment increased the expression of the vitamin D receptor and inhibited Transforming growth factor-β1 (TGF-β1)/Smad3 signaling pathway in rats kidneys with chronic kidney disease. Mechanistically, the upregulation of TGF-β1 and phosphorylation of Smad3 induced by vitamin D3 was reversed by activation of the vitamin D receptor. Our findings indicated that vitamin D3 is a potential antifibrotic drug in chronic kidney disease via the vitmin D receptor and inhibiting TGF-β1/Smad3 signaling pathway.

Vitamin D deficiency exacerbates hepatic oxidative stress and inflammation during acetaminophen-induced acute liver injury in mice

Several experiments confirmed that vitamin D3 protected against acetaminophen (APAP)-induced acute liver injury (ALI). This research aimed to evaluate the influence of vitamin D deficiency (VDD) on APAP-induced ALI. In VDD and VDD + APAP groups, mice were fed with VDD diet. In APAP and VDD + APAP groups, mice were intraperitoneally injected with a sublethal dose of APAP (150 mg/kg). A sublethal dose of APAP caused a slight elevation of ALT and AST. Interestingly, APAP-induced elevation of ALT and AST was aggravated in VDD-fed mice. APAP-induced hepatic necrosis was exacerbated in VDD-fed mice. In addition, APAP-induced hepatocyte death, measured using TUNEL assay, was exacerbated in VDD-fed mice. Additional experiment showed that APAP-induced hepatic GSH depletion and lipid peroxidation were exacerbated in VDD-fed mice. Moreover, APAP-induced upregulation of antioxidant genes, such as hepatic heme oxygenase-1 (Ho-1), glutathione peroxidase (Gshpx), superoxide dismutase 1 (Sod1) and catalase enzymes (Cat), was aggravated in VDD-fed mice. Although a sublethal dose of APAP did not cause hepatic inflammation, hepatic proinflammatory cytokines and chemokines, such as Tnf-α, Kc, Mcp-1 and Mip2, were upregulated in VDD-fed mice treated with APAP. These results provide experimental data that VDD exacerbates hepatic oxidative stress and inflammation during APAP-induced ALI.

Effect of meloxicam (cyclooygenase-2 inhibitor) versus vitamin D3 (cholecalciferol) as ameliorating agents of progressive doxorubicin-induced nephrotoxicity in rats

Doxorubicin (DOX)-induced nephropathy hampered its antineoplastic efficiency. The objective of the current work is to assess the prospective ameliorating effects of meloxicam versus vitamin D3 (Vit D3, cholecalciferol) against progressive DOX-induced nephropathy in rats trying to ascertain the possible mechanism underlying such amelioration. Ninety Male Wistar rats were randomly distributed to five experimental groups for 3 weeks, with saline, meloxicam (daily), DOX (single dose), Vit D3+DOX, or both meloxicam and DOX. We measured levels of urinary protein, serum creatinine, malondialdehyde (MDA) and renal reduced glutathione (GSH). In addition, tumor necrosis factor-alpha (TNF-α) expression and renal histopathology were assessed. Meloxicam alone treated group revealed no significant difference in urinary protein and serum creatinine. It also presented non-significant reduction in the MDA content while an increase in the reduced GSH content in contrast to the control group, which is more evident after the first week. Renal sections of rats received meloxicam only showed no significant histological changes and negative immunoreactivity compared to the control group. DOX induced a significant increase in urinary protein, serum creatinine, decrease reduced GSH, increased renal MDA and disrupted renal morphometric parameters and histology with increased TNF-α expression. Combination groups of Vit D3+DOX and meloxicam+DOX showed improvement of all DOX disturbed parameters. Meloxicam showed better results most likely due to anti-inflammatory and antioxidant activities superimposing the immune-modulatory effect of Vit D3. So, it is recommended to use meloxicam in patients receiving DOX as a renoprotective agent in addition to its analgesic effects required by cancer patients.

Vitamin D deficiency exacerbates bleomycin-induced pulmonary fibrosis partially through aggravating TGF-β/Smad2/3-mediated epithelial-mesenchymal transition

Background

Our earlier report indicated that active vitamin D3 inhibited epithelial-mesenchymal transition (EMT) in bleomycin (BLM)-induced pulmonary fibrosis. The objective of this study was to further investigate whether vitamin D deficiency exacerbates BLM-induced pulmonary fibrosis.

Methods

This study consists of two independent experiments. Experiment 1, male mice were fed with vitamin D deficient (VDD) fodder. Experiment 2, Cyp27b1^+/+, Cyp27b1^+/− and Cyp27b1^−/− mice were fed with standard diet. For pulmonary fibrosis, mice were intratracheally instilled with a single dose of BLM (1.5 mg/kg). Serum 25(OH) D level was measured. Pulmonary collagen deposition was assessed by Sirius red staining. EMT was measured and transforming growth factor-beta (TGF-β)/Smad3 signaling was evaluated in the lungs of BLM-treated mice.

Results

The relative weight of lungs was elevated in BLM-treated mice. Col1α1 and Col1α2, two collagen protein genes, were upregulated, and collagen deposition, as determined by Sirius red staining, was observed in the lungs of BLM-treated mice. E-cadherin, an epithelial marker, was downregulated. By contrast, vimentin and α-SMA, two EMT markers, were upregulated in the lungs of BLM-treated mice. Pulmonary TGF-β/Smad3 signaling was activated in BLM-induced lung fibrosis. Further analysis showed that feeding VDD diet, leading to vitamin D deficiency, aggravated elevation of BLM-induced relative lung weight. Moreover, feeding VDD diet aggravated BLM-induced TGF-β/Smad3 activation and subsequent EMT in the lungs. In addition, feeding VDD diet exacerbated BLM-induced pulmonary fibrosis. Additional experiment showed that Cyp27b1 gene knockout, leading to active vitamin D3 deficiency, exacerbated BLM-induced pulmonary fibrosis. Moreover, Cyp27b1 gene knockout aggravated pulmonary TGF-β/Smad2/3 activation and subsequent EMT in BLM-induced lung fibrosis.

Conclusion

Vitamin D deficiency exacerbates BLM-induced pulmonary fibrosis partially through aggravating TGF-β/Smad2/3-mediated EMT in the lungs.

The Vitamin D status is associated with serum C-reactive protein and adhesion molecules in patients with renal cell carcinoma

Low vitamin D status is associated with an increased risk of renal cell carcinoma (RCC). This study investigated the association of vitamin D status with serum C-reactive protein (CRP) and adhesion molecules among RCC patients. Fifty newly diagnosed RCC patients and 100 age- and sex-matched controls were recruited. As expected, serum 25(OH)D level was lower in RCC patients than in controls. By contrast, serum levels of CRP, an inflammatory molecule, and ICAM, LAMA4 and EpCAM, three adhesion molecules, were higher in RCC patients than in controls. All RCC patients were divided into two groups: H-VitD (>20 ng/ml) or L-VitD (<20 ng/ml). Interestingly, the levels of serum CRP and all adhesion molecules were higher in RCC patients with L-VitD than those with H-VitD. Nuclear vitamin D receptor (VDR) was downregulated and nuclear factor kappa B (NF-κB) was activated in cancerous tissues. The in vitro experiments found that VitD3 suppressed NF-κB activation and adhesion molecules in RCC cells. Moreover, VitD3 suppressed NF-κB through reinforcing physical interaction between VDR and NF-κB p65 subunit in RCC cells. These results provide a mechanistic explanation for the association among low vitamin D status, local inflammation and increased expression of adhesion molecules among RCC patients.

Co-targeting of endothelin-A and vitamin D receptors: a novel strategy to ameliorate cisplatin-induced nephrotoxicity

BACKGROUND

Although modulation of the vitamin D receptor (VDR) and endothelin-A receptor (ETAR) has previously been reported to offer renoprotection against cisplatin-induced nephrotoxicity, the possible interaction between the ET-1 and vitamin D pathways remains obscure. Therefore, the present study addressed the possible interaction between these signalling pathways using BQ-123 (a selective ETAR blocker) and alfacalcidol (a vitamin D3 analogue) separately or in combination.

METHODS

Male Sprague-Dawley rats were divided into the following groups: control (DMSO orally), cisplatin (single dose of 6 mg/kg ip; nephrotoxicity model), cisplatin + BQ-123 (1 mg/kg BQ-123 ip 1 h before and 1 day after cisplatin), cisplatin + alfacalcidol (50 ng/kg alfacalcidol orally 5 days before and 14 days after cisplatin), and cisplatin + BQ-123+alfacalcidol. Nephrotoxicity was evaluated 96 h and 14 days following cisplatin administration.

RESULTS

Both BQ-123 and alfacalcidol counteracted cisplatin-induced nephrotoxic changes. Specifically, they reduced serum creatinine and urea levels; renal tumour necrosis factor-alpha (TNF-α), transforming growth factor-beta1 (TGF-β1), and phosphorylated nuclear factor-kappa B (pNF-κB) content; and caspase-3 activity. They downregulated ET-1 and ETAR expression and ameliorated cisplatin-induced acute tubular necrosis. In addition, the treatments have increased VDR and endothelin-B receptor (ETBR) expression; however, BQ-123 did not affect ETBR. The effect of the combination regimen surpassed that of each drug alone.

CONCLUSION

These findings highlight the potential cross-talk between vitamin D and ET-1 pathways and pave the way for future preclinical/clinical studies to explore further mechanisms involved in this cross-talk.

The correlation between low vitamin D status and renal interleukin-6/STAT3 hyper-activation in patients with clear cell renal cell carcinoma

Low vitamin D status has been associated with increased risks of renal cell carcinoma (RCC). This study aimed to analyze the link between low vitamin D status and interleukin (IL)-6/STAT3 hyper-activation in clear cell RCC (ccRCC) patients. Forty-three newly diagnosed ccRCC patients and 86 age- and sex-matched controls were recruited. The association between low vitamin D status and IL-6/STAT3 hyper-activation was analyzed. Proliferation makersand STAT3 signal were evaluated. As expected, serum IL-6 level was higher in ccRCC patients than in controls. Moreover, serum IL-6 level was reversely correlated with serum 25(OH)D in ccRCC patients but not in controls. In addition, STAT3 signaling was hyper-activated in cancerous tissue. CcRCC patients were divided into three groups according to serum 25(OH)D level: vitamin D sufficiency (VitD-S, ≥30 ng/ml), vitamin D insufficiency (VitD-I, ≥20 and <30 ng/ml) or vitamin D deficiency (VitD-D, <20 ng/ml). Serum IL-6 was higher in ccRCC patients with VitD-D than those with VitD-S/VitD-I. Cancerous pSTAT3 level was higher in ccRCC patients with VitD-D than those with VitD-S/VitD-I. The number of pSTAT3⁺ nuclei in cancerous tissue was more in ccRCC patients with VitD-D than those with VitD-S/VitD-I. The expressions of cancerous PCNA, cyclin D1 and Ki-67, three markers of proliferation, were higher in ccRCC patients with VitD-D than those with VitD-S/VitD-I. The in vitro experiments showed that active vitamin D3 inhibited LPS-induced STAT3 phosphorylation in ACHN cells. Our results provide evidence that low vitamin D status is correlated with hyper-activation of cancerous IL-6/STAT3 and proliferation in ccRCC patients.

Native Hypovitaminosis D in CKD Patients: From Experimental Evidence to Clinical Practice

Native hypovitaminosis D (n-hVITD) is frequently found from the early stages of chronic kidney disease (CKD) and its prevalence increases with CKD progression. Even if the implications of n-hVITD in chronic kidney disease-mineral bone disorder (CKD-MBD) have been extensively characterized in the literature, there is a lot of debate nowadays about the so called “unconventional effects” of native vitamin D (25(OH)VitD) supplementation in CKD patients. In this review, highlights of the dimension of the problem of n-hVITD in CKD stages 2–5 ND patients will be presented. In addition, it will focus on the “unconventional effects” of 25(OH)VitD supplementation, the clinical impact of n-hVITD and the most significant interventional studies regarding 25(OH)VitD supplementation in CKD stages 2–5 ND.

Vitamin D receptor expression in peripheral blood mononuclear cells is inversely associated with disease activity and inflammation in lupus patients

OBJECTIVE

Systemic lupus erythematosus (SLE) is characterized by uncontrolled production of pro-inflammatory cytokines. Vitamin D receptor (VDR) has potent anti-inflammatory activities. The aim of this study was to examine the correlation between VDR expression and inflammation and disease activity in patients with SLE.

METHODS

Ninety-five SLE patients were recruited and divided into two groups, active and inactive, according to their SLE disease activity index (SLEDAI)-2 K, and 40 healthy individuals served as controls. The expression of VDR and NF-κB p65 in peripheral blood mononuclear cells (PBMCs) was determined by quantitative RT-PCR and Western blotting. VDR expression was correlated with inflammatory and diseases parameters in SLE patients. VDR regulation was also studied in THP-1 and Jurkat cell lines.

RESULTS

PBMC VDR expression was downregulated in SLE patients, especially in the active SLE group. VDR mRNA levels were negatively correlated with SLEDAI-2 K (r = - 0.348, P = 0.001), Systemic Lupus International Collaborating Clinics (SLICC) renal activity scores (r = - 0.346, P = 0.014), and proteinuria (r = - 0.309, P = 0.002) and positively associated with serum complement C3 levels (r = 0.316, P = 0.002). Multiple stepwise regression analysis indicated that PBMC VDR downregulation was an independent risk factor for SLEDAI-2 K. VDR levels were also negatively correlated with NF-κB p65 (r = - 0.339, P = 0.001), TNF-α (r = - 0.268, P = 0.009), and IL-6 (r = - 0.313, P = 0.002) levels. In monocyte and T lymphocyte cell lines, TNF-α suppressed VDR expression, whereas 1,25-dihydroxyvitamin D blocked TNF-α-induced VDR downregulation.

CONCLUSION

PBMC VDR expression is inversely associated with disease activity and inflammation in SLE patients, and VDR downregulation is likely driven by inflammation.

Protective effect of calcitriol on rhabdomyolysis-induced acute kidney injury in rats

Glycerol injection in rats can lead to rhabdomyolysis, with the release of the intracellular muscle content to the extracellular compartment and acute kidney injury (AKI). Oxidative stress and the inflammatory processes contribute to the disturbances in renal function and structure observed in this model. This study evaluated the effect of calcitriol administration in AKI induced by rhabdomyolysis and its relationship with oxidative damage and inflammatory process. Male Wistar Hannover rats were treated with calcitriol (6 ng/day) or vehicle (0.9% NaCl) for 7 days and were injected with 50% glycerol or saline 3 days after the beginning of calcitriol or saline administration. Four days after glycerol or saline injection, urine, plasma and renal tissue samples were collected for renal function and structural analysis. The oxidative stress and the inflammatory processes were also evaluated. Glycerol-injected rats presented increased sodium fractional excretion and decreased glomerular filtration rates. These alterations were associated with tubular injury in the renal cortex. These animals also presented increased oxidative damage, apoptosis, inflammation, higher urinary excretion of vitamin D-binding protein and decreased cubilin expression in renal tissue. All these alterations were less intense in calcitriol-treated animals. This effect was associated with decreases in oxidative damage and inflammation.

Pretreatment with Cholecalciferol Alleviates Renal Cellular Stress Response during Ischemia/Reperfusion-Induced Acute Kidney Injury

Background

Cellular stress is involved in ischemia/reperfusion- (I/R-) induced acute kidney injury (AKI). This study is aimed at investigating the effects of pretreatment with cholecalciferol on renal oxidative stress and endoplasmic reticulum (ER) stress during I/R-induced AKI.

Methods

I/R-induced AKI was established by cross-clamping renal pedicles for 90 minutes and then reperfusion. In the Chol + I/R group, mice were orally administered with three doses of cholecalciferol (25 μg/kg) at 1, 24, and 48 h before ischemia. Renal cellular stress and kidney injury were measured at different time points after reperfusion.

Results

I/R-induced AKI was alleviated in mice pretreated with cholecalciferol. In addition, I/R-induced renal cell apoptosis, as determined by TUNEL, was suppressed by cholecalciferol. Additional experiment showed that I/R-induced upregulation of renal GRP78 and CHOP was inhibited by cholecalciferol. I/R-induced renal IRE1α and eIF2α phosphorylation was attenuated by cholecalciferol. Moreover, I/R-induced renal GSH depletion, lipid peroxidation, and protein nitration were blocked in mice pretreated with cholecalciferol. I/R-induced upregulation of renal NADPH oxidases, such as p47phox, gp91phox, and nox4, was inhibited by cholecalciferol. I/R-induced upregulation of heme oxygenase- (HO-) 1, gshpx and gshrd, was attenuated in mice pretreated with cholecalciferol.

Conclusions

Pretreatment with cholecalciferol protects against I/R-induced AKI partially through suppressing renal cellular stress response.

Vitamin D receptor activation protects against lipopolysaccharide-induced acute kidney injury through suppression of tubular cell apoptosis

Acute kidney injury (AKI) is a common complication of sepsis characterized by a rapid degradation of renal function. The effect of vitamin D on AKI remains poorly understood. Here, we showed that vitamin D receptor (VDR) activation protects against lipopolysaccharide (LPS)-induced AKI by blocking renal tubular epithelial cell apoptosis. Mice lacking VDR developed more severe AKI than wild-type (WT) control mice after LPS treatment, which was manifested by marked increases in body weight loss and accumulation of serum blood urea nitrogen and creatinine as well as the magnitude of apoptosis of tubular epithelial cells. In the renal cortex, LPS treatment led to more dramatic downregulation of Bcl-2, more robust induction of p53-upregulated modulator of apoptosis (PUMA) and miR-155, and more severe caspase-3 activation in VDR knockout mice compared with WT control mice. Conversely, paricalcitol pretreatment markedly prevented LPS-induced AKI. Paricalcitol ameliorated body weight loss, attenuated serum blood urea nitrogen and creatinine accumulation, blocked tubular cell apoptosis, prevented the suppression of Bcl-2, and reversed PUMA and miR-155 induction and caspase-3 activation in LPS-treated WT mice. In HK2 cells, LPS induced PUMA and miR-155 by activating NF-κB, whereas 1,25(OH)₂D₃ blocked PUMA and miR-155 induction by repressing NF-κB activation. Both PUMA and miR-155 target Bcl-2 to promote apoptosis; namely, PUMA inhibits Bcl-2 activity, whereas miR-155 promotes Bcl-2 mRNA degradation and inhibits Bcl-2 protein translation. Collectively, these data provide strong evidence that LPS induces tubular cell apoptosis via upregulating PUMA and miR-155, whereas vitamin D/VDR signaling protects against AKI by blocking NF-κB-mediated PUMA and miR-155 upregulation.

Prediction of Drug Positioning for Quan-Du-Zhong Capsules Against Hypertensive Nephropathy Based on the Robustness of Disease Network

Hypertensive nephropathy (HN) is a medical condition in which chronic high blood pressure causes different kidney damage, including vascular, glomerular and tubulointerstitial lesions. For HN patients, glomerular and tubulointerstitial lesions occur in different renal structure with distinct mechanisms in the progression of renal damage. As an extraction of Eucommia ulmoides, Quan-du-zhong capsule (QDZJN) has the potential to treat HN due to antihypertensive and renal protective activities. Complicated mechanism of HN underlying various renal lesions and the “multi-component and multi-target” characteristics of QDZJN make identifying drug positioning for various renal lesions of HN complex. Here, we proposed an approach based on drug perturbation of disease network robustness, that is used to assess QDZJN positioning for various HN lesions. Topological characteristics of drug-attacked nodes in disease network were used to evaluated nodes importance to network. To evaluate drug attack on the whole disease network of various HN lesions, the robustness of disease networks before/after drug attack were assessed and compared with null models generated from random networks. We found that potential targets of QDZJN were specifically expressed in the kidneys and tended to participate in the “inflammatory response,” “regulation of blood pressure,” and “response to LPS and hypoxia,” and they were also key factors of HN. Based on network robustness assessment, QDZJN may specifically target glomeruli account to the stronger influence on glomerular network after removal of its potential targets. This prediction strategy of drug positioning is suitable for multi-component drugs based on drug perturbation of disease network robustness for two renal compartments, glomeruli and tubules. A stronger influence on the disease network of glomeruli than of tubules indicated that QDZJN may specifically target glomerular lesion of HN patients and will provide more evidence for precise clinical application of QDZJN against HN. Drug positioning approach we proposed also provides a new strategy for predicting precise clinical use of multi-target drugs.

1,25 Dihydroxyvitamin D3 Enhances the Antifibroid Effects of Ulipristal Acetate in Human Uterine Fibroids

BACKGROUND

Both European and American trials showed superior effect of ulipristal acetate (UPA) to placebo. However, the latter, which included black patients with known higher vitaminD3 deficiency risk, showed lower rate of amenorrhea responders and insignificant uterine fibroid (UF) size reduction. Our objective is to investigate whether adding vitamin D₃ to UPA can enhance UPA potency on UF phenotype in vitro.

METHODS

We screened the antiproliferative effect of different (UPA/vitaminD3) combinations on UF cell proliferation using dimethylthiazolyl diphenyltetrazolium bromide assay. Cells then were treated with UPA 100 nM in the presence or absence of vitamin D₃ 100 nM, and expression level of several markers related to proliferation, apoptosis, fibrosis, inflammation, and angiogenesis was measured on RNA or at protein level using quantitative real-time polymerase chain reaction, Western blot, immunofluorescence, or multiplex enzyme-linked immunosorbent assay techniques.

RESULTS

Significant dose- and time-dependent growth inhibitory effects of UPA/vitamin D₃ combinations were observed compared to untreated cells at 2 and 4 days (P < .05). Importantly, vitamin D₃/UPA combination significantly reduced cell proliferation as compared to UPA at 2, 4, 6, and 8 days (P < .05). Combination treatment significantly decreased protein expression of proliferation markers Ki-67, PCNA, and CyclinD1 by more than 50% compared to UPA (P < .05) along with a significant increase in apoptosis induction. Combination treatment resulted in a 2-fold decrease in protein levels of extracellular matrix markers collagen-1 and fibronectin besides pro-fibrogenic cytokine transforming growth factor β3 (P < .05). Moreover, it significantly decreased the production of pro-inflammatory cytokines interleukins 6, 8, 1α, and 1β compared to UPA (P < .05).

CONCLUSION

Combination of vitamin D₃ with UPA exhibits additional and orchestrated anti-UF effects, therefore might offer a more favorable clinical option.

Protective effect of sesamin in lipopolysaccharide-induced mouse model of acute kidney injury via attenuation of oxidative stress, inflammation, and apoptosis

CONTEXT

Acute kidney injury (AKI) is considered a major public health concern in today's world. Sepsis-induced AKI is large as a result of exposure to lipopolysaccharide (LPS) that is the major outer membrane component of Gram-negative bacteria. Sesamin is the main lignan of sesame seeds with multiple protective effects.

OBJECTIVE

In this research, we tried to demonstrate the protective effect of sesamin pretreatment in LPS-induced mouse model of AKI.

METHODS

LPS was injected at a single dose of 10 mg/kg (i.p.) and sesamin was given p.o. at doses of 25, 50, or 100 mg/kg, one hour prior to LPS.

RESULTS

Treatment of LPS-challenged mice with sesamin reduced serum level of creatinine and blood urea nitrogen (BUN) and returned back renal oxidative stress-related parameters including glutathione (GSH), malondialdehyde (MDA), and activity of catalase and superoxide dismutase (SOD). Moreover, sesamin alleviated inappropriate changes of renal nuclear factor-kappaB (NF-κB), toll-like receptor 4 (TLR4), cyclooxygenase-2 (COX2), tumor necrosis factor α (TNFα), interleukin-6, DNA fragmentation (an apoptotic index), and nuclear factor (erythroid-derived 2)-like 2 (Nrf2). In addition, sesamin diminished magnitude of kidney tissue damage due to LPS.

CONCLUSION

In summary, sesamin could dose-dependently abrogate LPS-induced AKI via attenuation of renal oxidative stress, inflammation, and apoptosis.

Obeticholic acid alleviate lipopolysaccharide-induced acute lung injury via its anti-inflammatory effects in mice

Acute lung injury (ALI) is a common disease that may result in acute respiratory failure and death. However, there are still no effective treatments for ALI. Several studies have shown that farnesoid X receptor (FXR) has an anti-inflammatory effect. We investigated the effects of obeticholic acid (OCA), an agonist of FXR, on Lipopolysaccharide (LPS)-induced ALI in mice. Sixty male mice were randomly divided into six groups, and orally administered with or without OCA once daily for 3 consecutive days before LPS (1.0 mg/kg). Animals were sacrificed at 0 h, 2 h or 6 h after LPS. As expected, OCA enhanced pulmonary FXR activity. OCA prevented LPS-induced ALI. Additional experiment showed that OCA alleviated LPS-induced up-regulation of pulmonary pro-inflammatory and chemokine genes. Moreover, OCA also repressed LPS-induced the release of TNF-α and KC in serum and bronchoalveolar lavage fluid. In contrast, OCA further up-regulated LPS-induced the expression of Il-10, an anti-inflammatory cytokine. Further study showed that OCA inhibited LPS-evoked NF-κB signaling in the lungs. OCA attenuated LPS-induced ERK1/2, JNK, p38 and Akt phosphorylation in the lungs. Overall, these results suggest that OCA prevent LPS-induced ALI may be through enhancing pulmonary FXR activity and then blockading several inflammatory signaling pathways.

Farnesoid X receptor agonist obeticholic acid inhibits renal inflammation and oxidative stress during lipopolysaccharide-induced acute kidney injury

It is increasingly recognized that farnesoid X receptor (FXR) has anti-inflammatory and antioxidant activities. The present study investigated the effects of obeticholic acid (OCA), a novel synthetic FXR agonist, on renal inflammation and oxidative stress in a model of sepsis-induced acute kidney injury. All mice except controls were intraperitoneally injected with lipopolysaccharide (LPS, 2.0 mg/kg). In the OCA + LPS group, mice were orally pretreated with three doses of OCA (5 mg/kg) at 48, 24 and 1 h before LPS injection. Interestingly, OCA pretreatment alleviated LPS-induced renal dysfunction and pathological damage. Moreover, OCA pretreatment repressed renal inflammatory cytokines and chemokines during LPS-induced acute kidney injury. In addition, OCA blocked nuclear translocation of nuclear factor kappa B (NF-κB) p65 and p50 subunits in tubular epithelial cells of renal cortex. Additional experiment showed that OCA pretreatment attenuated LPS-induced renal glutathione depletion, lipid peroxidation and protein nitration. Moreover, OCA pretreatment inhibited the upregulation of renal NADPH oxidase and inos genes during LPS-induced acute kidney injury. In conclusion, OCA pretreatment protects against sepsis-induced acute kidney injury through inhibiting renal inflammation and oxidative stress. These results provide evidence for roles of FXR as an important regulator of inflammation and oxidative stress in the kidney.

Dietary vitamin D3 supplementation protects laying hens against lipopolysaccharide-induced immunological stress

Background

The effects of vitamin D on the immune function of laying hens are not well understood. This study investigated the effects of vitamin D₃ (VD₃) on laying performance and immunological functions in laying hens under Escherichia coli lipopolysaccharide (LPS) challenge.

Methods

In experiment one, 360 Jinghong-1 strain layers (32 weeks) were randomly divided into four groups with six replicates per group and 15 hens per replicate. Hens were fed a basal diet supplemented with different levels of VD₃ (0; 500; 1500; or 3000 IU VD₃/kg of diet) for 10 weeks to determine laying performance, egg quality, and other parameters. In experiment two, 24 Jinghong laying hens (32 weeks) were fed basal diets with either 0 or 3000 IU VD₃/kg of diet. After 10 weeks of feeding, six hens from each treatment were injected intravenously with 8 mg/kg of body weight of either LPS or saline. Blood and spleen samples were obtained for immune parameter analysis 4 h after injection.

Results

VD₃ deficiency reduced egg production and egg quality; in addition, feed intake and feed-to-egg ratio increased. No significant differences were observed in these parameters except eggshell strength between dietary VD₃ supplemental levels at 500; 1500; and 3000 IU VD₃/kg of diet. VD₃ deficiency increased serum hormone (calcitonin, parathyroid hormone, estradiol, and progesterone) and cytokine (IL-6, IL-10) levels, the ratio of IFN-γ to IL-4, myeloperoxidase activity and total IgG content in the serum, and upregulated the blood CD3⁺ T cell population. Splenic retinoid X receptor (RXR), nuclear factor-κB (NF-κB), inducible nitric oxide synthase (iNOS), and polymeric immunoglobulin receptor (pIgR) gene mRNA levels were upregulated in VD₃-deficienct hens. VD₃ deficiency significantly reduced serum Follicle stimulating hormone (FSH) and Luteinizing hormone (LH) concentrations and the number of CD4⁺CD25⁺ T cells in the blood. These changes were completely normalized by VD₃ sufficiency. LPS reduced serum LH concentration, splenic lysozyme, and pIgR gene mRNA levels. LPS induced an increase in total serum IgM levels and the percentage of CD8⁺ T cells in the blood. The changes were completely reversed by VD₃ addition.

Conclusion

VD₃ supplementation could protect laying hens not only from VD₃ deficiency but also from immunological stress.

Drug repurposing in kidney disease

Drug repurposing, is the re-tasking of known medications for new clinical indications. Advantages, compared to de novo drug development, include reduced cost and time to market plus the added benefit of a known pharmacokinetic and safety profiles. Suitable drug candidates are identified through serendipitous observations, data mining, or increased understanding of disease mechanisms. This review highlights drugs suited for repurposing in kidney disease. The main cause of mortality in patients with chronic kidney disease is cardiovascular disease. Hence, we have included CV endpoints for the drugs. This review begins with candidates in acute kidney injury: vasodilators levosimendan and vitamin D, followed by candidates in CKD, with particular focus on diabetic kidney disease, autosomal dominant polycystic kidney disease, and focal segmental glomerulosclerosis. Examples include glucose-lowering drugs (sodium glucose co-transporter 2 inhibitors, glucagon-like peptide 1 agonists, and metformin), which have mechanistic potential for cardiac and/or renal protection beyond glucose lowering, with broader applicability to the nondiabetic population; xanthine oxidase inhibitors (allopurinol, febuxostat), selective endothelin receptor A antagonist (atrasentan), Janus kinase inhibitor (baricitinib), selective costimulation modulator (abatacept), pentoxyfylline, and the DNA demethylating agent/vasodilator (hydralazine).

Vitamin D Receptor: A Novel Therapeutic Target for Kidney Diseases

BACKGROUND

Kidney disease is a serious problem that adversely affects human health, but critical knowledge is lacking on how to effectively treat established chronic kidney disease. Mounting evidence from animal and clinical studies has suggested that Vitamin D Receptor (VDR) activation has beneficial effects on various renal diseases.

METHODS

A structured search of published research literature regarding VDR structure and function, VDR in various renal diseases (e.g., IgA nephropathy, idiopathic nephrotic syndrome, renal cell carcinoma, diabetic nephropathy, lupus nephritis) and therapies targeting VDR was performed for several databases.

RESULT

Included in this study are the results from 177 published research articles. Evidence from these papers indicates that VDR activation is involved in the protection against renal injury in kidney diseases by a variety of mechanisms, including suppression of RAS activation, anti-inflammation, inhibiting renal fibrogenesis, restoring mitochondrial function, suppression of autoimmunity and renal cell apoptosis.

CONCLUSION

VDR offers an attractive druggable target for renal diseases. Increasing our understanding of VDR in the kidney is a fertile area of research and may provide effective weapons in the fight against kidney diseases.

Low vitamin D status is associated with inflammation in patients with prostate cancer

Vitamin D deficiency has been associated with increased risks of prostate cancer. Nevertheless, the mechanisms remain unclear. The aim of this study was to analyze the association among prostate cancer, vitamin D status and inflammation. Sixty patients with newly diagnosed prostate cancer and 120 age-matched controls were recruited for this study. Vitamin D status was evaluated and serum inflammatory molecules were measured. Serum 25-(OH)D was lower in patients with prostate cancer. Moreover, serum 25(OH)D was lower in patients with severe prostate cancer than patients with mild and moderate prostate cancer. By contrast, serum C-reactive protein (CRP) and interleukin (IL)-8, two inflammatory molecules, were elevated in patients with prostate cancer. Serum 25-(OH)D was negatively correlated with serum CRP and IL-8 in patients with prostate cancer. Additional analysis showed that the percentage of vitamin D receptor positive nucleus in the prostate was reduced in patients with prostate cancer. By contrast, the percentage of nuclear factor kappa B p65-positive nucleus was elevated in patients with prostate cancer. Our results provide evidence that there is an association among prostate cancer, vitamin D deficiency and inflammatory signaling. Inflammation may be an important mediator for prostate cancer progression in patients with low vitamin D status.

Effect of endoplasmic reticulum stress on metabolic and stress signaling and kidney-specific functions in Madin-Darby bovine kidney cells

Recent studies demonstrated induction of endoplasmic reticulum (ER) stress in tissues of cows after parturition, but knowledge about the effect of ER stress on important cellular processes, such as critical signaling and metabolic pathways, in cattle is scarce. Thus, the present study aimed to investigate the effect of ER stress induction on nuclear factor-κB (NF-κB), nuclear factor E2-related factor 2 (Nrf2), and sterol regulatory element-binding protein (SREBF1) pathway in Madin-Darby bovine kidney (MDBK) cells, a widely used in vitro model in ruminant research. To consider the kidney origin of MDBK cells, the effect on renal distal tubular cell-specific functions, such as transport processes and regulation of 1,25(OH)₂D₃ levels, was also studied. Treatment of MDBK cells with 2 different ER stress inducers, thapsigargin (TG) and tunicamycin (TM), strongly induced ER stress as evident from induction of ER stress target genes, increased phosphorylation of PKR-like ER kinase, and enhanced splicing of X-box binding protein 1. The TM decreased the protein concentration of NF-κB p50 and the mRNA levels of the NF-κB target genes. Likewise, TG decreased the mRNA concentration of tumor necrosis factor and tended to decrease NF-κB p50 protein and mRNA levels of NF-κB target genes. The mRNA levels of most of the Nrf2 target genes investigated were reduced by TG and TM in MDBK cells. Both ER stress inducers reduced the mRNA levels of SREBF1 and its target genes in MDBK cells. Interestingly, TG decreased, but TM increased the mRNA level of the Ca²⁺ binding protein calbindin 1, whereas the mRNA level of the plasma membrane Ca²⁺-transporting ATPase 1 remained unchained. The mRNA level of the cytochrome P450 component 24A1 involved in 1α-hydroxylation of 25(OH)D₃ was strongly elevated, whereas the mRNA level of the cytochrome P450 component 27A1 catalyzing the breakdown of 1,25(OH)₂D₃ was markedly reduced by both ER stress inducers. The concentration of 1,25(OH)₂D₃ in the supernatant of MDBK cells was increased by approximately 15% by both TG and TM. The present study indicates that under conditions of ER stress, critical signaling pathways, such as NF-κB, Nrf2, and SREBF1, are inhibited, whereas the formation of 1,25(OH)₂D₃ is stimulated in bovine MDBK cells. Future studies are necessary to clarify the physiological relevance of these findings.

Histological and Immunohistochemical Basis of the Effect of Aminoguanidine on Renal Changes Associated with Hemorrhagic Shock in a Rat Model

Acute kidney failure is the main cause of death among patients with severe trauma due to massive blood loss and hemorrhagic shock (HS). Renal cell injury is caused by tissue ischemia. Renal ischemia initiates a complex and interconnected chain of events resulting in cell injury and renal cell necrosis. Nitric oxide plays a crucial role in renal function and can be inhibited by aminoguanidine (AG). We studied whether AG can ameliorate pathological renal changes associated with HS syndrome in a rat model and explored the AG protection mechanism. Rats were intraperitoneally injected with heparin sodium and mean arterial blood pressure was monitored. Animals were divided into three groups: control (without hemorrhage), with or without intra-arterially injected AG; HS (blood continuously withdrawn or reinfused to maintain an MABP of 35-40 mmHg); and HS with AG. We found that AG decreased plasma concentrations of urea, creatinine, and nitrates; ameliorated histological changes of HS-induced rats; and decreased the expressions of inducible nitrogen oxide synthase (iNOS), proapoptotic protein (BAX), and vitamin D receptors (VDR). AG ameliorated kidney injury by inhibiting iNOS resulting in decreased BAX and VDR expressions. Therefore, a therapeutic strategy targeting AG may provide new insights into kidney injury during severe shock.

Low vitamin D status is associated with advanced liver fibrosis in patients with nonalcoholic fatty liver disease

Several studies explored the association between vitamin D status and nonalcoholic fatty liver disease with contradictory results. We aimed to investigate the association between vitamin D status, inflammatory cytokines and liver fibrosis in nonalcoholic fatty liver disease patients. Two hundred nineteen nonalcoholic fatty liver disease patients and 166 age- and gender- matched healthy controls were recruited for this study. Serum 25(OH)D was measured by radioimmunoassay. Serum interleukin-8 and transforming growth factor-β1 were measured using ELISA. Serum 25(OH)D was only marginally decreased in nonalcoholic fatty liver disease patients. Interestingly, serum 25(OH)D was markedly reduced in nonalcoholic fatty liver disease patients with advanced liver fibrosis compared to nonalcoholic fatty liver disease patients with indeterminate liver fibrosis and no advanced fibrosis. Logistic regression analysis showed that there was an inverse association between serum 25(OH)D and severity of liver fibrosis in nonalcoholic fatty liver disease patients. Further analysis showed that serum interleukin-8 was elevated in nonalcoholic fatty liver disease patients, the highest interleukin-8 in patients with advanced fibrosis. An inverse correlation between serum 25(OH)D and interleukin-8 was observed in nonalcoholic fatty liver disease patients with and without liver fibrosis. Although serum transforming growth factor-β1 was slightly elevated in nonalcoholic fatty liver disease patients, serum transforming growth factor-β1 was reduced in nonalcoholic fatty liver disease patients with advanced fibrosis. Unexpectedly, a positive correlation between serum 25(OH)D and transforming growth factor-β1 was observed in nonalcoholic fatty liver disease patients with advanced fibrosis. In conclusion, low vitamin D status is associated with advanced liver fibrosis in nonalcoholic fatty liver disease patients. Interleukin-8 may be an important mediator for hepatic fibrosis in nonalcoholic fatty liver disease patients with low vitamin D status.

Vitamin D3 pretreatment protects against lipopolysaccharide-induced early embryo loss through its anti-inflammatory effects

PROBLEM

Increasing evidence demonstrates that inflammatory cytokines are involved in LPS-induced adverse pregnant outcomes including early embryo loss. Vitamin D3 (VitD3) has anti-inflammatory activity. We aimed to investigate the effects of vitamin D3 (VitD3) on LPS-induced early embryo loss in mice.

METHOD OF STUDY

All pregnant mice except controls were intraperitoneally (ip) injected with LPS on GD7. In VitD3 alone and LPS+VitD3 groups, pregnant mice were pretreated with VitD3 by gavage daily from GD5 to GD7.

RESULTS

LPS caused 62.5% pregnant mice with early embryo loss. Interestingly, the rate of abortion dropped to 14.3% when pregnant mice were pretreated with VitD3. Additional experiment showed that VitD3 significantly attenuated LPS-evoked elevation on TNF-α, IFN-γ, MIP-2, and nitrate plus nitrite in maternal serum. In addition, VitD3 alleviated LPS-induced COX-2 expression in the decidua and attenuated the elevation of PGF2α in maternal serum. Although VitD3 had no effect on IL-10 in maternal serum, it induced further elevation of serum IL-10 level in LPS-treated mice. Further analysis showed that VitD3 activated VDR signaling, simultaneously inhibited LPS-induced nuclear translocation of NF-κB p65 subunits in the decidua.

CONCLUSIONS

VitD3 protects mice from LPS-induced early embryo loss at least partially through its anti-inflammatory effects.

Obeticholic Acid Protects against Lipopolysaccharide-Induced Fetal Death and Intrauterine Growth Restriction through Its Anti-Inflammatory Activity

Farnesoid X receptor (FXR) is expressed in human and rodent placentas. Nevertheless, its function remains obscure. This study investigated the effects of obeticholic acid (OCA), a novel synthetic FXR agonist, on LPS-induced fetal death and intrauterine growth restriction. All pregnant mice except controls were i.p. injected with LPS (100 μg/kg) daily from gestational day (GD) 15 to GD17. Some pregnant mice were orally administered with OCA (5 mg/kg) daily from GD13 to GD17. As expected, placental FXR signaling was activated by OCA. OCA pretreatment protected against LPS-induced fetal death. In addition, OCA pretreatment alleviated LPS-induced reduction of fetal weight and crown-rump length. Additional experiments showed that OCA inhibited LPS-evoked TNF-α in maternal serum and amniotic fluid. Moreover, OCA significantly attenuated LPS-induced upregulation of placental proinflammatory genes including Tnf-α, Il-1β, IL-6, Il-12, Mip-2, Kc, and Mcp-1 By contrast, OCA elevated anti-inflammatory cytokine IL-10 in maternal serum, amniotic fluid, and placenta. Further analysis showed that OCA blocked nuclear translocation of NF-κB p65 and p50 subunits in trophoblast giant cells of the labyrinth zone. These results provide a mechanistic explanation for placental FXR-mediated anti-inflammatory activity. Overall, this study provides evidence for roles of FXR as an important regulator of placental inflammation.

Calcitriol inhibits tumor necrosis factor alpha and macrophage inflammatory protein-2 during lipopolysaccharide-induced acute lung injury in mice

Acute lung injury is a common complication of sepsis in intensive care unit patients with an extremely high mortality. The present study investigated the effects of calcitriol, the active form of vitamin D, on tumor necrosis factor alpha (TNF-α) and macrophage inflammatory protein-2 (MIP-2) in sepsis-induced acute lung injury. Mice were intraperitoneally (i.p.) injected with lipopolysaccharide (LPS, 1.0mg/kg) to establish the animal model of sepsis-induced acute lung injury. Some mice were i.p. injected with calcitriol (1.0μg/kg) before LPS injection. An obvious infiltration of inflammatory cells in the lungs was observed beginning at 1h after LPS injection. Correspondingly, TNF-α and MIP-2 in sera and lung homogenates were markedly elevated in LPS-treated mice. Interestingly, calcitriol obviously alleviated LPS-induced infiltration of inflammatory cells in the lungs. Moreover, calcitriol markedly attenuated LPS-induced elevation of TNF-α and MIP-2 in sera and lung homogenates. Further analysis showed that calcitriol repressed LPS-induced p38 mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) phosphorylation. In addition, calcitriol blocked LPS-induced nuclear translocation of nuclear factor kappa B (NF-κB) p65 and p50 subunit in the lungs. Taken together, these results suggest that calcitriol inhibits inflammatory cytokines production in LPS-induced acute lung injury.

Ce-based metal-organic frameworks and DNAzyme-assisted recycling as dual signal amplifiers for sensitive electrochemical detection of lipopolysaccharide

In this work, a sensitive electrochemical aptasensor was designed for lipopolysaccharide (LPS) detection based on Ce-based metal-organic frameworks (Ce-MOFs) and Zn(2+) dependent DNAzyme-assisted recycling as dual signal amplifiers. Herein, Ce-MOFs were decorated with gold nanoparticles (AuNPs) to obtain AuNPs/Ce-MOFs, and the resultant AuNPs/Ce-MOFs not only acted as nanocarriers to capture -SH terminated hairpin probes 2 (HP2) for acquiring HP2/AuNPs/Ce-MOFs signal probes, but also as catalysts to catalyze the oxidation of ascorbic acid (AA). In the presence of target LPS, report DNA was released from the prepared duplex DNA and then hybridized with hairpin probes 1 (HP1, which were immobilized on the electrode). With the help of Zn(2+), report DNA could act as Zn(2+) dependent DNAzyme to cleave HP1 circularly. Then a large amount of capture probes were produced on the electrode to combine with HP2/AuNPs/Ce-MOFs signal probes. When the detection solution contained electrochemical substrate of AA, AuNPs/Ce-MOFs could oxide AA to obtain enhanced signal. Under the optimized conditions, this proposed aptasensor for LPS exhibited a low detection limit of 3.3 fg/mL with a wide linear range from 10fg/mL to 100ng/mL.

Rosiglitazone pretreatment protects against lipopolysaccharide-induced fetal demise through inhibiting placental inflammation

Peroxisome proliferator-activated receptor (PPAR)-γ is highly expressed in human and rodent placentas. Nevertheless, its function remains obscure. The present study investigated the effects of rosiglitazone, a PPAR-γ agonist, on LPS-induced fetal death. All pregnant mice except controls were intraperitoneally injected with LPS (150 μg/kg) daily from gestational day (GD)15 to GD17. As expected, maternal LPS injection caused placental inflammation and resulted in 63.6% fetal death in dams that completed the pregnancy. Interestingly, LPS-induced fetal mortality was reduced to 16.0% when pregnant mice were pretreated with RSG. Additional experiment showed that rosiglitazone pretreatment inhibited LPS-induced expressions of tumor necrosis factor (Tnf)-α, interleukin (Il)-1β, Il-6, macrophage inflammatory protein (Mip)-2 and keratinocyte-derived chemokine (Kc) in mouse placenta. Although rosiglitazone had little effect on LPS-evoked elevation of IL-10 in amniotic fluid, it alleviated LPS-evoked release of TNF-α and MIP-2 in amniotic fluid. Further analysis showed that pretreatment with rosiglitazone, which activated placental PPAR-γ signaling, simultaneously suppressed LPS-evoked nuclear factor kappa B (NF-κB) activation and blocked nuclear translocation of NF-κB p65 and p50 subunits in trophoblast giant cells of the labyrinth layer. These results provide a mechanistic explanation for PPAR-γ-mediated anti-inflammatory activity in the placentas. Overall, the present study provides additional evidence for roles of PPAR-γ as an important regulator of placental inflammation.