Klotho sensitive regulation of dendritic cell functions by vitamin E

Regulation of Dendritic Cell Functions by Vitamins as Promising Therapeutic Strategy for Immune System Disorders

A functional immune system is crucial for a healthy life, protecting from infections, tumors, or autoimmune disorders; these are accomplished by the interaction between various immune cells. Nourishment, particularly micronutrients, are very important components in the immune system balance, therefore this review emphasizes the vitamins (D, E, A, C) and Dendritic cells' subsets due to vitamins' roles in immune processes, especially on dendritic cells' functions, maturation, and cytokine production. Current studies reveal significant benefits related to vitamins, including vitamin E, which can contribute to the control of dendritic cells' function and maturation. Furthermore, vitamin D plays an immunoregulatory and anti-inflammatory role in the immune system. Metabolite of vitamin A which is called retinoic acid leads to T cells' differentiation to T helper 1 or T helper 17, so low levels of this vitamin exacerbate the menace of infectious diseases, and vitamin C has anti-oxidant effects on dendritic cells and modulate their activation and differentiation program. Additionally, the correlation between the amount of vitamin and the occurrence or progression of allergic diseases and autoimmunity disorders is discussed according to the results of previous studies.

Association of Dietary Vitamin C Consumption with Serum Klotho Concentrations

BACKGROUND

Klotho is widely recognized as a protein that combats aging and possesses antioxidative characteristics, which have been implicated in the pathophysiology of numerous diseases. There is emerging evidence suggesting that the consumption of dietary nutrients, particularly those rich in antioxidants, could be associated with serum Klotho concentrations. Dietary vitamin C is one of the critical nutrients that possesses antioxidant properties. Nonetheless, the association between dietary vitamin C consumption and serum Klotho concentrations remains unclear.

OBJECTIVE

Aiming to evaluate the relationship between serum Klotho concentrations and dietary vitamin C consumption among Americans aged 40 to 79, we conducted a population-based study.

METHODS

From the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2016, a grand total of 11,282 individuals who met the criteria were selected as eligible participants for the study. Serum Klotho concentrations were measured using an ELISA kit that is commercially available. Trained interviewers evaluated the consumption of dietary vitamin C in the diet through a 24-hour dietary recall technique. A generalized linear model was used to evaluate the correlation between the consumption of dietary vitamin C in the diet and serum Klotho concentrations. Further examination was conducted using restricted cubic spline (RCS) analysis to explore the non-linear correlation between dietary vitamin C consumption in the diet and serum Klotho concentrations.

RESULTS

After accounting for possible confounding factors, serum Klotho concentrations rose by 1.17% (95% confidence interval (CI): 0.37%, 1.99%) with every standard deviation (SD) rise in dietary vitamin C consumption. With the first quintile of dietary vitamin C consumption as a reference, the percentage change of serum Klotho concentrations in the fifth quintile of dietary vitamin C consumption was 3.66% higher (95% CI: 1.05%, 6.32%). In older, normal-weight, and male participants, the subgroup analysis revealed a stronger correlation between dietary vitamin C consumption and serum Klotho concentrations. Analysis of RCS showed a linear positive association between dietary vitamin C consumption and the levels of serum Klotho concentrations.

CONCLUSION

The findings of this research indicate a strong and positive correlation between dietary vitamin C consumption and serum Klotho concentrations among the general adult population in the United States. Further studies are needed to validate the present findings and to explore specific mechanisms.

Nutritional Behavior in European Countries during COVID-19 Pandemic-A Review

COVID-19 is highly linked with hyperinflammation and dysfunction of the immune cells. Studies have shown that adequate nutrition, a modifiable factor affecting immunity and limiting systemic inflammation, may play an adjunct role in combating the negative consequences of SARS-CoV-2 infection. Due to the global lockdown conditions, the COVID-19 pandemic has contributed, among others, to restrictions on fresh food availability and changes in lifestyle and eating behaviors. The aim of this paper was to review the data regarding eating habits in European countries within the general population of adults and some specific subpopulations, including obese, diabetic, and psychiatric patients, during the COVID-19 pandemic. The PubMed database and the official websites of medical organizations and associations were searched for the phrases "COVID" and "eating habits". Papers regarding the pediatric population, non-European countries, presenting aggregated data from different countries worldwide, and reviews were excluded. During the COVID-19 pandemic, unhealthy lifestyles and eating behaviors were commonly reported. These included increased snacking, intake of caloric foods, such as sweets, pastries, and beverages, and a decline in physical activity. Data suggest that poor eating habits that create a positive energy balance have persisted over time as an additional post-COVID negative consequence.

Nutraceuticals as Potential Therapeutic Modulators in Immunometabolism

Nutraceuticals act as cellular and functional modulators, contributing to the homeostasis of physiological processes. In an inflammatory microenvironment, these functional foods can interact with the immune system by modulating or balancing the exacerbated proinflammatory response. In this process, immune cells, such as antigen-presenting cells (APCs), identify danger signals and, after interacting with T lymphocytes, induce a specific effector response. Moreover, this conditions their change of state with phenotypical and functional modifications from the resting state to the activated and effector state, supposing an increase in their energy requirements that affect their intracellular metabolism, with each immune cell showing a unique metabolic signature. Thus, nutraceuticals, such as polyphenols, vitamins, fatty acids, and sulforaphane, represent an active option to use therapeutically for health or the prevention of different pathologies, including obesity, metabolic syndrome, and diabetes. To regulate the inflammation associated with these pathologies, intervention in metabolic pathways through the modulation of metabolic energy with nutraceuticals is an attractive strategy that allows inducing important changes in cellular properties. Thus, we provide an overview of the link between metabolism, immune function, and nutraceuticals in chronic inflammatory processes associated with obesity and diabetes, paying particular attention to nutritional effects on APC and T cell immunometabolism, as well as the mechanisms required in the change in energetic pathways involved after their activation.

Immunostimulant and Antidepressant Effect of Natural Compounds in the Management of Covid-19 Symptoms

In recent years, the use of natural compounds as adjuvant treatments and alternatives to traditional pharmacological therapies has become increasingly popular. These compounds have a wide range of biological effects, such as: antioxidant, anti-aging, hypocholesterolizing, hypoglycemic, antitumoral, antidepressant, anxiolytic activity, etc. Almost all of these compounds are easily available and are contained in different foods. At the end of 2019 the Coronavirus SARS-CoV-2 appeared in China and quickly spread throughout the world, causing a pandemic. The most common symptoms of this infection are dry cough, fever, dyspnea, and in severe cases bilateral interstitial pneumonia, with consequences that can lead to death. The nations, in trying to prevent the spread of infection, have imposed social distancing and lockdown measures on their citizens. This had a strong psychological-social impact, leading to phobic, anxious and depressive states. Pharmacological therapy could be accompanied by treatment with several natural compounds, such as vitamins, baicalein, zinc and essential oils. These compounds possess marked immunostimulant activity, strengthening the immune response and mitigating interactions between the virus and the host cell. They also have an antidepressant effect, acting on certain neurotransmitters.

Allergy Modulation by N-3 Long Chain Polyunsaturated Fatty Acids and Fat Soluble Nutrients of the Mediterranean Diet

The Mediterranean diet, containing valuable nutrients such as n-3 long chain poly-unsaturated fatty acids (LCPUFAs) and other fat-soluble micronutrients, is known for its health promoting and anti-inflammatory effects. Its valuable elements might help in the battle against the rising prevalence of non-communicable diseases (NCD), including the development of allergic diseases and other (chronic) inflammatory diseases. The fat fraction of the Mediterranean diet contains bioactive fatty acids but can also serve as a matrix to dissolve and increase the uptake of fat-soluble vitamins and phytochemicals, such as luteolin, quercetin, resveratrol and lycopene with known immunomodulatory and anti-inflammatory capacities. Especially n-3 LCPUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived from marine oils can target specific receptors or signaling cascades, act as eicosanoid precursors and/or alter membrane fluidity and lipid raft formation, hereby exhibiting anti-inflammatory properties. Beyond n-3 LCPUFAs, fat-soluble vitamins A, D, E, and K1/2 have the potential to affect pro-inflammatory signaling cascades by interacting with receptors or activating/inhibiting signaling proteins or phosphorylation in immune cells (DCs, T-cells, mast cells) involved in allergic sensitization or the elicitation/effector phase of allergic reactions. Moreover, fat-soluble plant-derived phytochemicals can manipulate signaling cascades, mostly by interacting with other receptors or signaling proteins compared to those modified by fat-soluble vitamins, suggesting potential additive or synergistic actions by applying a combination of these nutrients which are all part of the regular Mediterranean diet. Research concerning the effects of phytochemicals such as polyphenols has been hampered due to their poor bio-availability. However, their solubility and uptake are improved by applying them within the dietary fat matrix. Alternatively, they can be prepared for targeted delivery by means of pharmaceutical approaches such as encapsulation within liposomes or even unique nanoparticles. This review illuminates the molecular mechanisms of action and possible immunomodulatory effects of n-3 LCPUFAs and fat-soluble micronutrients from the Mediterranean diet in allergic disease development and allergic inflammation. This will enable us to further appreciate how to make use of the beneficial effects of n-3 LCPUFAs, fat-soluble vitamins and a selection of phytochemicals as active biological components in allergy prevention and/or symptom reduction.

A Rapid Advice Guideline for the Prevention of Novel Coronavirus Through Nutritional Intervention

Purpose of Review

An unexpected and sudden outbreak of a novel infection known as a coronavirus (COVID-19) has imposed important problems to global well-being and economy. Based upon current researches, this virus is spreading from one human to another through respiratory droplets, i.e. cough and sneeze. Till now, there has not been any specific treatment found for this virus. Hence, there is a critical need to discover alternative techniques to cope with the current scenario.

Recent Findings

This review conducted an online search for prevention of coronavirus infection with the help of nutritional interventions. It has been observed that the effect of the virus is mostly on the individual with low immunity, individual affected with diseases like diabetes, and individual using any immune-suppressed drug or having past history of major surgeries or severe medical conditions.

Summary

Therefore, consuming foods which boost immunity helps in preventing respiratory-related disorder or suppressing diseases-related problems, which could be helpful in controlling the spread of this virus. In conclusion, it has been suggested that before the beginning of generalised treatments and interventions in each infected patient, nutritional status should be evaluated, as it can help in creating a specific nutrition intervention for the infected individual.

Strengthening the Immune System and Reducing Inflammation and Oxidative Stress through Diet and Nutrition: Considerations during the COVID-19 Crisis

The coronavirus-disease 2019 (COVID-19) was announced as a global pandemic by the World Health Organization. Challenges arise concerning how to optimally support the immune system in the general population, especially under self-confinement. An optimal immune response depends on an adequate diet and nutrition in order to keep infection at bay. For example, sufficient protein intake is crucial for optimal antibody production. Low micronutrient status, such as of vitamin A or zinc, has been associated with increased infection risk. Frequently, poor nutrient status is associated with inflammation and oxidative stress, which in turn can impact the immune system. Dietary constituents with especially high anti-inflammatory and antioxidant capacity include vitamin C, vitamin E, and phytochemicals such as carotenoids and polyphenols. Several of these can interact with transcription factors such as NF-kB and Nrf-2, related to anti-inflammatory and antioxidant effects, respectively. Vitamin D in particular may perturb viral cellular infection via interacting with cell entry receptors (angiotensin converting enzyme 2), ACE2. Dietary fiber, fermented by the gut microbiota into short-chain fatty acids, has also been shown to produce anti-inflammatory effects. In this review, we highlight the importance of an optimal status of relevant nutrients to effectively reduce inflammation and oxidative stress, thereby strengthening the immune system during the COVID-19 crisis.

Ca2+-Mediated Surface Polydopamine Engineering to Program Dendritic Cell Maturation

Engineering of cell surfaces holds promise in manipulating cellular activities in a physicochemical route as a complement to the biological approach. Mediated by Ca²⁺, a quick and convenient yet cytocompatible method is used to achieve surface engineering, by which polydopamine nanostructures can be in situ grown onto dendritic cell (DC) surfaces within 10 min. Ca²⁺, as the physical bridge between the negative cell surface and polydopamine, avoids the direct chemical polymerization of polydopamine onto the cell surface, critically important to maintain the cell viability. As a proof of concept in potential applications, this cell surface engineering shows a good control toward DC maturation. Upon surface polydopamine engineering, bone-marrow-derived DC exhibits a unique bidirectional control of maturation. The polydopamine structure enables effective suppression of DC activation by acting as an efficient scavenger of reactive oxygen species, a key signal during maturation. Conversely, an 808 nm laser irradiation can remotely relieve the suppressed state and effectively activate DC maturation by the photoheat effect of polydopamine (39 °C). The work provides an easily implemented, straightforward approach to achieve cell surface engineering, through which the DC maturation can be controlled.

Regulation of p38MAPK-mediated dendritic cell functions by the deubiquitylase otubain 1

Dendritic cells (DCs) are professional antigen presenting cells (APCs) that represent the essential link between innate and acquired immunity. Otubain (OTUB) 1 is shown to deubiquitinate TRAFs to suppress virus-induced inflammatory response. MAPK, a downstream molecule of TRAFs, is involved in regulating LPS-induced immune reactions and its activation is sensitive to the presence of OTUB1. Little is known about contributions of OTUB1 to changes in biological properties of DCs. The present study, therefore, explored whether DC functions are influenced by OTUB1. To this end, DCs were isolated and cultured with GM-CSF to attain bone marrow-derived DCs (BMDCs) and followed by treatment with lipopolysaccharide (LPS) in the presence or absence of OTUB1 siRNA. Expression of markers of cellular maturation and proliferation were analyzed by flow cytometry, and secretion of inflammatory cytokines and ability to stimulate CD4⁺ T-cells in allogenic mixed leukocyte reaction (allo-MLR) by ELISA, cell migration by a transwell migration assay and phagocytic capacity by FITC-dextran uptake measurement. As a result, treatment of the cells with OTUB1 siRNA prolonged activation of p38MAPK, increased CD54 expression and IL-6 release and reduced FITC-dextran uptake. Moreover, cytokine release produced from CD4⁺ T-cells in allo-MLR was different. The enhanced level of IFN-γ, but not other cytokine production was observed in the presence of siRNA OTUB1. All the effects were completely abolished when the cells were exposed with p38MAPK inhibitor SB203580. In conclusion, OTUB1 prevents the prolonged activation of p38MAPK, which in turn compromises DC functions.

The Role of Vitamin E in Immunity

Vitamin E is a fat-soluble antioxidant that can protect the polyunsaturated fatty acids (PUFAs) in the membrane from oxidation, regulate the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), and modulate signal transduction. Immunomodulatory effects of vitamin E have been observed in animal and human models under normal and disease conditions. With advances in understating of the development, function, and regulation of dendritic cells (DCs), macrophages, natural killer (NK) cells, T cells, and B cells, recent studies have focused on vitamin E’s effects on specific immune cells. This review will summarize the immunological changes observed with vitamin E intervention in animals and humans, and then describe the cell-specific effects of vitamin E in order to understand the mechanisms of immunomodulation and implications of vitamin E for immunological diseases.

Changes in expression of klotho affect physiological processes, diseases, and cancer

Klotho (KL) encodes a single-pass transmembrane protein and is predominantly expressed in the kidney, parathyroid glands, and choroid plexus. Genetic studies on the KL gene have revealed that DNA hypermethylation is one of the major risk factors for aging, diseases, and cancer. Besides, KL exerts anti-inflammatory and anti-tumor effects by regulating signaling pathways and the expression of target genes. KL participates in modulation of the insulin/insulin-like growth factor-1 (IGF-1) signaling, which induces the growth hormone (GH) secretion. Accordingly, KL mutant mice display multiple aging-like phenotypes, which are ameliorated by overexpression of KL. Therefore, KL is an important contributor to lifespan. KL is further identified as a regulator of calcium (Ca²⁺) channel-dependent cell physiological processes. KL has been also shown to induce cancer cell apoptosis, thus, it is considered as a potential tumor suppressor. Our recent studies have indicated that KL modulates an influx of Ca²⁺ from the extracellular space, leading to a change in CCL21-dependent migration in dendritic cells (DCs). Interestingly, the regulation of the expression of KL was mediated through a phosphoinositide 3-kinase (PI3K) pathway in DCs. Moreover, downregulating of KL expression by using siRNA knockdown technique, we observed that the expression of Ca²⁺ channels including Orai3, but not Orai1, Orai2, TRPV5 and TRPV6 was significantly reduced in KL-silenced as compared to control BMDCs. Clearly, additional research is required to define the role of KL in the regulation of organismic and cellular functions through the PI3K signaling and the expression of the Ca²⁺ channels.