Exploring vitamin D signalling within skin cancer

The neuroprotective effect of vitamin D in Parkinson's disease: association or causation

Parkinson's disease (PD) is a chronic neurodegenerative disease (NDD) due to the degeneration of dopaminergic neurons (DNs) in the substantia nigra (SN). PD is characterized by diverse motor symptoms such as rigidity, resting tremors, and bradykinesia, and non-motor symptoms such as cognitive dysfunction and sleep disturbances. Vitamin D (VD), VD receptor (VDR), and VD metabolites are present in the brain and play a role in maintaining the development, differentiation, and functions of the DNs. VDRs exert protective effects against PD neuropathology by modulating functional capacity and DNs neurotransmission in the SN. In virtue of its anti-inflammatory and antioxidant activities, VD could be effective in the prevention and treatment of PD. VD exerts a neuroprotective effect by reducing oxidative stress and mitochondrial dysfunction, and by increasing autophagy and brain-derived neurotrophic factor (BDNF). Low VD serum level is connected with cognitive dysfunction and the development of dementia in PD. The VD-mediated cognitive augmenting effect is interrelated to the safeguarding of synaptic plasticity and modulation of neurotransmitter release. VD deficiency is linked with the severity of olfactory dysfunction which precedes the progression of symptomatic PD. However, the precise role of VD in PD remains unidentified, and there is a conflict about whether treatment with VD can ameliorate PD or not.

Regular use of vitamin D supplement is associated with fewer melanoma cases compared to non-use: a cross-sectional study in 498 adult subjects at risk of skin cancers

There are conflicting results on the role of vitamin D system in cutaneous carcinogenesis. Therefore, it was investigated whether the use of oral vitamin D supplements associates with photoaging, actinic keratoses, pigment cell nevi, and skin cancers. In this cross-sectional study, 498 adults (aged 21-79 years, 253 males, 245 females, 96 with immunosuppression) subjects at risk of any type of skin cancer were examined, and possible confounding factors were evaluated. The subjects were divided into three groups based on their self-reported use of oral vitamin D supplements: non-use, occasional use, or regular use. The serum level of 25-hydroxyvitamin-D3 was analyzed in 260 subjects. In 402 immunocompetent subjects, vitamin D use did not associate with photoaging, actinic keratoses, nevi, basal, and squamous cell carcinoma. In contrast, there were lower percentages of subjects with a history of past or present melanoma (32/177, 18.1% versus 32/99, 32.3%, P  = 0.021) or any type of skin cancer (110/177, 62.1% versus 74/99, 74.7%, P  = 0.027) among regular users compared to non-users. In the logistic regression analysis, the odds ratio for melanoma was 0.447 ( P  = 0.016, 95% confidence interval, 0.231-0.862) among regular users. Furthermore, the investigator-estimated risk class of skin cancers was significantly lower among regular users. Serum 25-hydroxyvitamin-D3 did not show marked associations with skin-related parameters. The results on 96 immunosuppressed subjects were somewhat similar, although the number of subjects was low. In conclusion, regular use of vitamin D associates with fewer melanoma cases, when compared to non-use, but the causality between them is obscure.

Comparative transcriptome analysis reveals physiological responses in liver tissues of Epinephelus coioides under acute hypoxia stress

Hypoxia is a common stressor for aquatic animals, including Epinephelus coioides, with a considerable impact on sustainable aquaculture. E. coioides is a widely consumed fish in China owing to its high nutritious value and taste. However, water hypoxia caused by high density culture process has become a great threat to E. coioides culture, and its response to hypoxia stress has not been discussed before. Therefore, the aim of this study was to examine the response of E. coioides to acute hypoxia using transcriptomic techniques. To this end, RNA sequencing was performed on the liver tissues of fish exposed to normoxic and hypoxic conditions for 1 h. The results presented 503 differentially expressed genes (DEGs) in the liver tissue of fish exposed to hypoxic condition compared with those in the normoxic group. Enrichment analysis using the Gene Ontology database showed that the DEGs were mainly enriched for functions related to cell apoptosis signaling pathways, insulin resistance, antioxidant enzymes, and glycolysis/gluconeogenesis signaling pathways. KEGG enrichment analysis showed that HIF-1, PI3K-AKT, IL-17, NF-kappa B, and MAPK signaling pathways were significantly enriched by the DEGs. The DEGs were mainly involved in immune response, inflammatory response, cell apoptosis regulation, energy metabolism, and substance metabolism. Additionally, the hypoxia response in E. coioides was mainly regulated via the PI3K-AKT-HIF-1 signaling axis. Overall, the findings of this study contribute to the understanding of hypoxia stress response in E. coioides, and provides target genes for breeding hypoxia-tolerant Epinephelus spp.

Vitamin D Modulation of Mitochondrial Oxidative Metabolism and mTOR Enforces Stress Adaptations and Anticancer Responses

The relationship between the active form of vitamin D3 (1,25-dihydroxyvitamin D, 1,25(OH)2D) and reactive oxygen species (ROS), two integral signaling molecules of the cell, is poorly understood. This is striking, given that both factors are involved in cancer cell regulation and metabolism. Mitochondria (mt) dysfunction is one of the main drivers of cancer, producing more mitochondria, higher cellular energy, and ROS that can enhance oxidative stress and stress tolerance responses. To study the effects of 1,25(OH)2D on metabolic and mt dysfunction, we used the vitamin D receptor (VDR)-sensitive MG-63 osteosarcoma cell model. Using biochemical approaches, 1,25(OH)2D decreased mt ROS levels, membrane potential (ΔΨmt), biogenesis, and translation, while enforcing endoplasmic reticulum/mitohormetic stress adaptive responses. Using a mitochondria-focused transcriptomic approach, gene set enrichment and pathway analyses show that 1,25(OH)2D lowered mt fusion/fission and oxidative phosphorylation (OXPHOS). By contrast, mitophagy, ROS defense, and epigenetic gene regulation were enhanced after 1,25(OH)2D treatment, as well as key metabolic enzymes that regulate fluxes of substrates for cellular architecture and a shift toward non-oxidative energy metabolism. ATACseq revealed putative oxi-sensitive and tumor-suppressing transcription factors that may regulate important mt functional genes such as the mTORC1 inhibitor, DDIT4/REDD1. DDIT4/REDD1 was predominantly localized to the outer mt membrane in untreated MG-63 cells yet sequestered in the cytoplasm after 1,25(OH)2D and rotenone treatments, suggesting a level of control by membrane depolarization to facilitate its cytoplasmic mTORC1 inhibitory function. The results show that 1,25(OH)2D activates distinct adaptive metabolic responses involving mitochondria to regain redox balance and control the growth of osteosarcoma cells. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Early Stress-Response Gene REDD1 Controls Oxazolone-Induced Allergic Contact Dermatitis

REDD1 is an energy sensor and stress-induced mTOR inhibitor. Recently, its novel role in linking metabolism and inflammation/immune responses has emerged. In this study, we assessed the role of REDD1 in murine oxazolone-induced allergic contact dermatitis (ACD), a T cell-dependent model with features of human ACD. A variety of immune indices, including edema, cellular infiltration, inflammatory gene expression, and glucocorticoid response, were compared in Redd1 knockout (KO) and isogenic (C57BL/6 × 129)F1 wild-type mice after sensitization and subsequent ear challenge with oxazolone. Despite relatively normal thymic profiles and similar T cell populations in the lymph nodes of naive Redd1 KO mice, early T cell expansion and cytokine production were profoundly impaired after sensitization. Surprisingly, higher steady-state populations of CD4⁺ and CD8⁺ T cells, as well as macrophages (CD45⁺/Ly-6G^-/CD11b⁺), dendritic cells (CD45⁺/Ly-6G^-/CD11c⁺), neutrophils (CD45⁺/Ly-6G⁺/CD11b⁺), and innate lymphoid cells (CD45⁺/Lineage^-/IL-7Ra⁺/ST2⁺/c-Kit⁺), were observed in the ears of naive Redd1 KO mice. Upon challenge, ear edema, T cell, macrophage, neutrophil, and dendritic cell infiltration into the ear was significantly reduced in Redd1 KO animals. Accordingly, we observed significantly lower induction of IFN-γ, IL-4, and other cytokines as well as proinflammatory factors, including TSLP, IL-33, IL-1β, IL-6, and TNF-α, in challenged ears of Redd1 KO mice. The response to glucocorticoid treatment was also diminished. Taken together, these data establish REDD1 as an essential immune modulator that influences both the initiation of ACD disease, by driving naive T cell activation, and the effector phase, by promoting immune cell trafficking in T cell-mediated skin inflammation.

Research progress of keratinocyte-programmed cell death in UV-induced Skin photodamage

Programmed cell death (PCD) is a basic component of life and an important terminal path for cells. A variety of biological events are associated with PCD, including the conservation of tissue homeostasis and removal of harmful cells. Overexposure of the skin to UV radiation causes skin photodamage. Keratinocytes are the first line of defence against ultraviolet radiation. During UV radiation, the keratinocyte can undergo four modes of PCD: apoptosis, pyroptosis, necroptosis and autophagy. The molecular mechanisms of these four modes of PCD have been widely studied as potential therapeutic targets for the prevention of UV-induced skin inflammation, ageing and skin cancer. In this review, we summarize the role of keratinocyte PCD in the pathogenesis of UV-induced skin photodamage. This article will provide new research directions for the design of intervention strategies for the treatment and prevention of skin photodamage.

Assessment of sun-related behavior and serum vitamin D in basal cell carcinoma: Preliminary results

Ultraviolet radiation (UV), mainly from sunlight, is the main risk factor of the most common human skin cancer, basal cell carcinoma (BCC). A positive effect of UV on the skin is its contribution to the synthesis of vitamin D, which is important in sustaining general health, but having high levels of vitamin D is considered a risk factor for BCC. However, vitamin D receptor has antagonistic effects to UV radiation in regulating Sonic Hedgehog pathway. This is a pilot study aimed at characterizing the sun-related behavior and vitamin D status of 52 BCC patients and 59 controls from our geographical area. Patients were included in 4 subgroups: Single, multiple, recurrent, and both multiple and recurrent BCCs. Patients, more than controls, had at least one sunburn in childhood and lentigines (P<0.001). Also, they spent daily, on average, more time in the sun than controls (P<0.001) (3.00-8.00 and 1.50-4.00 h respectively). Outdoor work was similar in both groups. Participants had lower vitamin D serum levels than expected. Due to the small number of cases, no statistically significant differences were found between the subgroups but some tendencies were noted. Patients with only one recurrent BCC had less sunburns than the ones who also developed tumors at multiple sites (P=0.2). Patients with multiple and recurrent tumors had slightly lower vitamin D levels compared with single BCC patients (P=0.1) although they used more vitamin D supplements after the BCC diagnosis (P=0.2). Having a diagnosis of BCC, made patients more compliant to the use of sunscreen cream, but even so, half of them still did not use it. In conclusion, more effort should be invested in sun-related education and public health actions should focus on vitamin D deficiencies.

Understanding the Biological Activities of Vitamin D in Type 1 Neurofibromatosis: New Insights into Disease Pathogenesis and Therapeutic Design

Vitamin D is a fat-soluble steroid hormone playing a pivotal role in calcium and phosphate homeostasis as well as in bone health. Vitamin D levels are not exclusively dependent on food intake. Indeed, the endogenous production-occurring in the skin and dependent on sun exposure-contributes to the majority amount of vitamin D present in the body. Since vitamin D receptors (VDRs) are ubiquitous and drive the expression of hundreds of genes, the interest in vitamin D has tremendously grown and its role in different diseases has been extensively studied. Several investigations indicated that vitamin D action extends far beyond bone health and calcium metabolism, showing broad effects on a variety of critical illnesses, including cancer, infections, cardiovascular and autoimmune diseases. Epidemiological studies indicated that low circulating vitamin D levels inversely correlate with cutaneous manifestations and bone abnormalities, clinical hallmarks of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant tumour predisposition syndrome causing significant pain and morbidity, for which limited treatment options are available. In this context, vitamin D or its analogues have been used to treat both skin and bone lesions in NF1 patients, alone or combined with other therapeutic agents. Here we provide an overview of vitamin D, its characteristic nutritional properties relevant for health benefits and its role in NF1 disorder. We focus on preclinical and clinical studies that demonstrated the clinical correlation between vitamin D status and NF1 disease, thus providing important insights into disease pathogenesis and new opportunities for targeted therapy.