SARS-CoV-2 non-structural protein 6 triggers NLRP3-dependent pyroptosis by targeting ATP6AP1

A recent mutation analysis suggested that Non-Structural Protein 6 (NSP6) of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a key determinant of the viral pathogenicity. Here, by transcriptome analysis, we demonstrated that the inflammasome-related NOD-like receptor signaling was activated in SARS-CoV-2-infected lung epithelial cells and Coronavirus Disease 2019 (COVID-19) patients’ lung tissues. The induction of inflammasomes/pyroptosis in patients with severe COVID-19 was confirmed by serological markers. Overexpression of NSP6 triggered NLRP3/ASC-dependent caspase-1 activation, interleukin-1β/18 maturation, and pyroptosis of lung epithelial cells. Upstream, NSP6 impaired lysosome acidification to inhibit autophagic flux, whose restoration by 1α,25-dihydroxyvitamin D3, metformin or polydatin abrogated NSP6-induced pyroptosis. NSP6 directly interacted with ATP6AP1, a vacuolar ATPase proton pump component, and inhibited its cleavage-mediated activation. L37F NSP6 variant, which was associated with asymptomatic COVID-19, exhibited reduced binding to ATP6AP1 and weakened ability to impair lysosome acidification to induce pyroptosis. Consistently, infection of cultured lung epithelial cells with live SARS-CoV-2 resulted in autophagic flux stagnation, inflammasome activation, and pyroptosis. Overall, this work supports that NSP6 of SARS-CoV-2 could induce inflammatory cell death in lung epithelial cells, through which pharmacological rectification of autophagic flux might be therapeutically exploited.

Serumal and Salivary 25(OH)D and 1,25(OH)D Levels of Head and Neck Cancer Patients

BACKGROUND: Saliva has been suggested as a substitute of serum for the detection of 25 Dihydroxyvitamin D (25(OH)D) in healthy people. However, investigation of salivary 1,25(OH)D has not been clearly reported. Vitamin plays important roles in inhibiting cancer progression. Current study was conducted to investigate serumal and salivary 25(OH)D) and 1,25(OH)D levels of healthy and head and neck cancer (HNC) subjects.METHODS: Research were conducted at Haji Adam Malik Hospital, Medan, Indonesia. Forty HNC and 40 healthy subjects were recruited and selected based on inclusion and exclusion criteria. Medical records were documented, followed by anthropometric evaluation and serum and saliva collection. Laboratory investigation for 25(OH)D and 1,25(OH) was performed using Enzyme-linked immunosorbent assay (ELISA) methods.RESULTS: Significant serumal (p=0.002) and salivary (p=0.016) 25(OH)D mean level differences of HNC and normal groups were obtained. More serumal or salivary 25(OH)D deficient subjects were found in control group than those in HNC group. Meanwhile, serumal and salivary 1,25(OH)D mean levels of HNC group were not significantly different with the ones of control group. There were significant correlations of serumal-salivary 25(OH)D as well as serumal-salivary 1,25(OH)D levels in normal group.CONCLUSION: Serumal and salivary 25(OH)D and 1,25(OH)D levels of HNC group were relatively normal. Salivary 25(OH)D and 1,25(OH)D could be suggested as substitutes for serumal ones.KEYWORDS: vitamin D, 25(OH)D, 1,25(OH)D, head and neck cancer

The CYP24A1 Gene Variant rs2762943 Is Associated With Low Serum 1,25- Dihydroxyvitamin D Levels In Multiple Sclerosis Patients

Background: Vitamin D is considered to play a role in multiple sclerosis (MS) etiopathogenesis. We recently identified a polymorphism located in the cytochrome P450 family 24 subfamily A member 1 (CYP24A1) gene, rs2762943, that was found to be associated with an increased risk for MS. CYP24A1 codes for a protein that is involved in the catabolism of the active form of vitamin D. Here, we investigated the immunological effects of carrying the risk allele for the rs2762943 polymorphism, as well as its role as genetic modifier in MS patients. Methods: Serum levels of 25‐hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25(OH)2D) were measured in a cohort of 167 MS patients. In a subgroup of these patients, expression levels of MHC class II and co-stimulatory molecules were determined by flow cytometry in blood cell populations, and the levels of proinflammatory (IFNG, GM-CSF, CXCL13) and anti-inflammatory (IL-10) cytokines and neurofilament light chain were measured by single-molecule array assays in serum samples. The effect of the rs2762943 polymorphism on disease activity and disability progression measures was evaluated in a cohort of 340 MS patients. Results: Compared to non-carriers, MS patients carrying the risk allele for rs2762943 were characterized by reduced levels of 1,25(OH)2D (p=0.0001), and elevated levels of IFNG (p=0.03) and GM-CSF (p=0.008), whereas no significant differences were observed between risk allele carriers and non-carriers groups for the other evaluated markers. The presence of the risk allele for rs2762943 had no significant impact on the annualized relapse rate, EDSS and MSSS measures during follow-up. However, risk allele carriers were younger at disease onset (p=0.04). Discussion: These findings suggest that the CYP24A1 rs2762943 gene variant plays a more important role on MS susceptibility than on disease prognosis, and is associated with lower 1,25(OH)2D levels and heightened pro-inflammatory environment in MS patients.

The Effects of Vitamin D on Immune System and Inflammatory Diseases

Immune cells, including dendritic cells, macrophages, and T and B cells, express the vitamin D receptor and 1α-hydroxylase. In vitro studies have shown that 1,25-dihydroxyvitamin D, the active form of vitamin D, has an anti-inflammatory effect. Recent epidemiological evidence has indicated a significant association between vitamin D deficiency and an increased incidence, or aggravation, of infectious diseases and inflammatory autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis. However, the impact of vitamin D on treatment and prevention, particularly in infectious diseases such as the 2019 coronavirus disease (COVID-19), remains controversial. Here, we review recent evidence associated with the relationship between vitamin D and inflammatory diseases and describe the underlying immunomodulatory effect of vitamin D.

Vitamin D-Dependent Rickets Type 1A in Two Siblings with a Hypomorphic CYP27B1 Variant Frequent in the African Population

Vitamin D-dependent type 1A rickets (VDDR-1A) is a rare autosomal recessive disease due to the inability to convert 25-hydroxyvitamin D [25(OH)D] to the active form 1.25-dihydroxyvitamin D [1.25(OH)2D] by the enzyme 25(OH)D-1α-hydroxylase leading to low or low-normal serum levels of [1.25(OH)2D].We report two sisters with rickets in whom the diagnosis of VDDR-1A was a challenge. They had normal 1.25(OH)2D levels, which are unusual with this condition but may be explained by the identified genotype. Both have compound heterozygous for two, most likely, hypomorphic CYP27B1 alleles: the novel p.(Arg117Gly) variant, and p.(Ala129Thr), which are present in 0.43% of the African population.This report illustrates the variability of clinical, laboratory, and radiological presentation between two sisters with the same genotype, during phases of faster or slower growth. Genetic testing was crucial for establishing the diagnosis that optimized the management and genetic counseling.

Role of Vitamin D in Cognitive Dysfunction: New Molecular Concepts and Discrepancies between Animal and Human Findings

Purpose of review: increasing evidence suggests that besides the several metabolic, endocrine, and immune functions of 1alpha,25-dihydroxyvitamin D (1,25(OH)2D), the neuronal effects of 1,25(OH)2D should also be considered an essential contributor to the development of cognition in the early years and its maintenance in aging. The developmental disabilities induced by vitamin D deficiency (VDD) include neurological disorders (e.g., attention deficit hyperactivity disorder, autism spectrum disorder, schizophrenia) characterized by cognitive dysfunction. On the other hand, VDD has frequently been associated with dementia of aging and neurodegenerative diseases (e.g., Alzheimer’s, Parkinson’s disease). Recent findings: various cells (i.e., neurons, astrocytes, and microglia) within the central nervous system (CNS) express vitamin D receptors (VDR). Moreover, some of them are capable of synthesizing and catabolizing 1,25(OH)2D via 25-hydroxyvitamin D 1alpha-hydroxylase (CYP27B1) and 25-hydroxyvitamin D 24-hydroxylase (CYP24A1) enzymes, respectively. Both 1,25(OH)2D and 25-hydroxyvitamin D were determined from different areas of the brain and their uneven distribution suggests that vitamin D signaling might have a paracrine or autocrine nature in the CNS. Although both cholecalciferol and 25-hydroxyvitamin D pass the blood–brain barrier, the influence of supplementation has not yet demonstrated to have a direct impact on neuronal functions. So, this review summarizes the existing evidence for the action of vitamin D on cognitive function in animal models and humans and discusses the possible pitfalls of therapeutic clinical translation.

Variable Clinical Presentation of Children with Hereditary Hypophosphatemic Rickets with Hypercalciuria: A Case Series and Review of the Literature

Introduction: Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH) is a rare condition of renal phosphate wasting due to SLC34A3 mutations [1]. Patients exhibit low serum phosphorus, high 1,25-dihydroxyvitamin D and inappropriately high urine phosphate and calcium. However, symptoms vary and little is known about specific phenotype-genotype correlations. Methods: We report three HHRH cases in unrelated 12-year-old, 9-year-old and 14-year-old patients and perform a systematic literature review. Results: All three patients exhibited labs typical of HHRH. Yet, their presentations differed and 2 novel SLC34A3 variants were identified. As found in the literature review, bone symptoms are most common (50%), followed by renal symptoms (17%), combined bone and renal symptoms (18%) and asymptomatic (9%). Conclusion: These three cases highlight the variability of presenting signs and symptoms among individuals with HHRH. An accurate diagnosis is critical, as treatment differs from other disorders of phosphate wasting, urinary stones, and mineralization defects.