Activation of vitamin D receptor attenuates high glucose-induced cellular injury partially dependent on CYP2J5 in murine renal tubule epithelial cell

The mechanism of cadmium exposure-induced lymph node necroptosis and inflammation in piglets: Activation of CYP450 through VDR / CREB1 pathway

Cadmium (Cd) is toxic non-essential heavy metal that precipitates adverse health effects in humans and animals, but the effect of Cd on lymph node toxicity of piglets is still unclear. In order to explore the possible molecular mechanism of Cd toxicity to lymph nodes of piglets, ten 6-week-old male weaned piglets were randomly divided into two groups, C group and Cd group. Group C was fed with basal diet, while group Cd was fed with basal diet supplemented with CdCl2 (20 mg/kg) for 40 days, the pigs were euthanized and the mesenteric, inguinal and submandibular lymph nodes (MLN, ILN, SLN) were collected. The results indicated that Cd could induce the inflammatory cell infiltration, microvascular hemorrhage, microthrombosis and cell necrosis in MLN, ILN and SLN of piglets, induced Cytochrome P450 proteins (CYP1A1、CYP2E1、CYP2A1 and CYP3A2) mRNA levels and the protein levels of Vitamin D receptor (VDR) and cAMP response element binding protein 1 (CREB1). In addition, Cd exposure upregulated the mRNA and protein levels of dynamin-related protein 1 (DRP1), receptor-interacting protein kinase 3 (RIP3), mixed lineage kinase domain-like protein (MLKL), and increased tumor necrosis factor-α (TNFα), interferon-γ (IFNγ), interleukin-2 (IL-2), interleukin-4 (IL-4), cyclooxygenase 2 (COX-2) protein levels, and the damage degree of three kinds of lymph nodes was similar after Cd exposure. In general, these results manifest that Cd exposure regulates VDR/CREB1 pathway, activates CYP450s, induces necroptosis of lymph nodes, and leads to inflammation.

Nuclear Receptors and Transcription Factors in Obesity-Related Kidney Disease

Both obesity and chronic kidney disease are increasingly common causes of morbidity and mortality worldwide. Although obesity often co-exists with diabetes and hypertension, it has become clear over the past several decades that obesity is an independent cause of chronic kidney disease, termed obesity-related glomerulopathy. This review defines the attributes of obesity-related glomerulopathy and describes potential pharmacologic interventions. Interventions discussed include peroxisome proliferator-activated receptors, the farnesoid X receptor, the Takeda G-protein-coupled receptor 5, and the vitamin D receptor.

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.

Vitamin D Effects on Bone Homeostasis and Cardiovascular System in Patients with Chronic Kidney Disease and Renal Transplant Recipients

Poor vitamin D status is common in patients with impaired renal function and represents one main component of the complex scenario of chronic kidney disease-mineral and bone disorder (CKD-MBD). Therapeutic and dietary efforts to limit the consequences of uremia-associated vitamin D deficiency are a current hot topic for researchers and clinicians in the nephrology area. Evidence indicates that the low levels of vitamin D in patients with CKD stage above 4 (GFR < 15 mL/min) have a multifactorial origin, mainly related to uremic malnutrition, namely impaired gastrointestinal absorption, dietary restrictions (low-protein and low-phosphate diets), and proteinuria. This condition is further worsened by the compromised response of CKD patients to high-dose cholecalciferol supplementation due to the defective activation of renal hydroxylation of vitamin D. Currently, the literature lacks large and interventional studies on the so-called non-calcemic activities of vitamin D and, above all, the modulation of renal and cardiovascular functions and immune response. Here, we review the current state of the art of the benefits of supplementation with native vitamin D in various clinical settings of nephrological interest: CKD, dialysis, and renal transplant, with a special focus on the effects on bone homeostasis and cardiovascular outcomes.

Antagonistic effect of VDR/CREB1 pathway on cadmium-induced apoptosis in porcine spleen

Cadmium (Cd) is a toxic trace element that can enter the environment with industrial waste and accumulate in the body but the health effects of Cd on ternary pigs are still lacking in research. In order to explore the effect of Cd on the apoptosis of pig spleen and its mechanism, this study chose ternary pig as the research object to detect relevant indicators in pig spleen under Cd exposure. The results of this study showed that Cd exposure can induce apoptosis by promoting the absorption of various toxic trace elements in the spleen and inducing oxidative stress. We also found that the mechanism of Cd-induced apoptosis is closely related to the VDR/CREB1 pathway. On the one hand, Cd exposure can activate VDR, and indirectly regulate the CYP family, affecting the normal function of the spleen. On the other hand, VDR and its downstream genes antagonize the toxicity of Cd by maintaining the stability of the mitochondrial-related endoplasmic reticulum membrane structure. Our research will help researchers to further understand the physiological toxicity of Cd.

Liver X receptor activation induces podocyte injury via inhibiting autophagic activity

Podocyte injury plays a key role in the occurrence and development of kidney diseases. Decreased autophagic activity in podocyte is closely related to its injury and the occurrence of proteinuria. Liver X receptors (LXRs), as metabolic nuclear receptors, participate in multiple pathophysiological processes and express in several tissues, including podocytes. Although the functional roles of LXRs in the liver, adipose tissue and intestine are well established; however, the effect of LXRs on podocytes function remains unclear. In this study, we used mouse podocytes cell line to investigate the effects of LXR activation on podocytes autophagy level and related signaling pathway by performing Western blotting, RT-PCR, GFP-mRFP-LC3 transfection, and immunofluorescence staining. Then, we tested this effect in STZ-induced diabetic mice. Transmission electron microscopy and immunohistochemistry were employed to explore the effects of LXR activation on podocytes function and autophagic activity. We found that LXR activation could inhibit autophagic flux through blocking the formation of autophagosome in podocytes in vitro which was possibly achieved by affecting AMPK, mTOR, and SIRT1 signaling pathways. Furthermore, LXR activation in vivo induced autophagy suppression in glomeruli, leading to aggravated podocyte injury. In summary, our findings indicated that activation of LXRs induced autophagy suppression, which in turn contributed to the podocyte injury.