RISING STARS: Androgens and immune cell function.

Androgens can modulate immune cell function and may contribute to differences in the prevalence and severity of common inflammatory conditions. Although most immune cells are androgen targets, our understanding of how changes in androgen bioavailability can affect immune responses is incomplete. Androgens alter immune cell composition, phenotype, and activation by modulating the expression and secretion of inflammatory mediators or by altering the development and maturation of immune cell precursors. Androgens are generally associated with having suppressive effects on the immune system, but their impacts are cell and tissue context-dependent and can be highly nuanced even within immune cell subsets. In response to androgens, innate immune cells such as neutrophils, monocytes, and macrophages increase the production of the anti-inflammatory cytokine IL-10 and decrease nitric oxide production. Androgens promote the differentiation of T cell subsets and reduce the production of inflammatory mediators, such as IFNG, IL-4 and IL-5. Additionally, androgens/androgen receptor can promote the maturation of B cells. Thus, androgens can be considered as immunomodulatory agents, but further work is required to understand the precise molecular pathways that are regulated at the intersection between endocrine and inflammatory signals. This narrative review focusses on summarising our current understanding of how androgens can alter immune cell function and how this might affect inflammatory responses in health and disease.

Cutaneous-immuno-neuro-endocrine (CINE) system: A complex enterprise transforming skin into a super organ.

Skin is now emerging as a complex realm of three chief systems viz. immune system, nervous system, and endocrine system. The cells involved in their intricate crosstalk, namely native skin cells, intra-cutaneous immune cells and cutaneous sensory neurons have diverse origin and distinct functions. However, recent studies have explored their role beyond their pre-defined functional boundaries, such that the cells shun their traditional functions and adopt unconventional roles. For example, the native skin cells, apart from providing for basic structural framework of skin, also perform special immune functions and participate in extensive neuro-endocrine circuitry, which were traditionally designated as functions of cutaneous resident immune cells and sensory neurons respectively. At the cellular level, this unique collaboration is brought out by special molecules called neuromediators including neurotransmitters, neuropeptides, neurotrophins, neurohormones and cytokines/chemokines. While this intricate crosstalk is essential for maintaining cutaneous homeostasis, its disruption is seen in various cutaneous diseases. Recent study models have led to a paradigm shift in our understanding of pathophysiology of many such disorders. In this review, we have described in detail the interaction of immune cells with neurons and native skin cells, role of neuromediators, the endocrine aspect in skin and current understanding of cutaneous neuro-immuno-endocrine loop in one of the commonest skin diseases, psoriasis. An accurate knowledge of this unique crosstalk can prove crucial in understanding the pathophysiology of different skin diseases and allow for generation of targeted therapeutic modalities.

Programmed and environmental determinants driving neonatal mucosal immune development.

The mucosal immune system of neonates goes through successive, non-redundant phases that support the developmental needs of the infant and ultimately establish immune homeostasis. These phases are informed by environmental cues, including dietary and microbial stimuli, but also evolutionary developmental programming that functions independently of external stimuli. The immune response to exogenous stimuli is tightly regulated during early life; thresholds are set within this neonatal "window of opportunity" that govern how the immune system will respond to diet, the microbiota, and pathogenic microorganisms in the future. Thus, changes in early-life exposure, such as breastfeeding or environmental and microbial stimuli, influence immunological and metabolic homeostasis and the risk of developing diseases such as asthma/allergy and obesity.

Shaping immunity for life: Layered development of CD8+ T cells.

Historically, the immune system was believed to develop along a linear axis of maturity from fetal life to adulthood. Now, it is clear that distinct layers of immune cells are generated from unique waves of hematopoietic progenitors during different windows of development. This model, known as the layered immune model, has provided a useful framework for understanding why distinct lineages of B cells and γδ T cells arise in succession and display unique functions in adulthood. However, the layered immune model has not been applied to CD8+ T cells, which are still often viewed as a uniform population of cells belonging to the same lineage, with functional differences between cells arising from environmental factors encountered during infection. Recent studies have challenged this idea, demonstrating that not all CD8+ T cells are created equally and that the functions of individual CD8+ T cells in adults are linked to when they were created in the host. In this review, we discuss the accumulating evidence suggesting there are distinct ontogenetic subpopulations of CD8+ T cells and propose that the layered immune model be extended to the CD8+ T cell compartment.

[Vitamins and Immune System Health].

Keeping the immune system healthy forms an effective way to fight infections. Past experience has shown that, in addition to effective interventions including vaccination, drug therapy, and non-pharmaceutical intervention (NPI), dietary nutrition and mental health are also key factors in maintaining immune system health and combating emerging and sudden outbreaks of infections. As the main dietary nutrients, vitamins are active regulators of the immune response and exert a critical impact on the immunity of the human body. Vitamin deficiency causes increased levels of inflammation and decreased immunity, which usually starts in the oral tissues. Appropriate vitamin supplementation can help the body optimize immune function, enhance oral immunity, and reduce the negative impact of pathogen infection on the human body, which makes it a feasible, effective, and universally applicable anti-infection solution. This review focuses on the immunomodulatory effects of vitamin A, B, C, D, and E and proposes that an omics-based new systemic approach will lead to a breakthrough of the limitations in traditional single-factor single-pathway research and provide the direction for the basic and applied research of vitamin immune regulation and anti-infection in all aspects.

Unravelling the Influence of Nutrition and Mental Stress on Immune Response.

The review article reveals the role of mental as well as biological phenomena working behind immunity. In recent times, irresistible illnesses and inflammation have been thought to be hereditary or the result of the natural working mechanism of the human body in response to the pathogenic variables working inside the human system. In the past few years, the importance of psychological adjustments, mental well-being and eating habits has been studied and shown to have a marked effect on immunity. Psychoneuroimmunology considers that mental disorders are strongly interrelated with the resistant reaction. Besides, the immunological components control the wellbeing of the individual. Psychosocial mediations help reduce disease severity and enhance the functioning of the immune system. Nutrition plays a vital role in immunity and thus has an influence on our mental health.

Brain borders at the central stage of neuroimmunology.

The concept of immune privilege suggests that the central nervous system is isolated from the immune system. However, recent studies have highlighted the borders of the central nervous system as central sites of neuro-immune interactions. Although the nervous and immune systems both function to maintain homeostasis, under rare circumstances, they can develop pathological interactions that lead to neurological or psychiatric diseases. Here we discuss recent findings that dissect the key anatomical, cellular and molecular mechanisms that enable neuro-immune responses at the borders of the brain and spinal cord and the implications of these interactions for diseases of the central nervous system.

New insight into DAVF pathology-Clues from meningeal immunity.

In recent years, with the current access in techniques, studies have significantly advanced the knowledge on meningeal immunity, revealing that the central nervous system (CNS) border acts as an immune landscape. The latest concept of meningeal immune system is a tertiary structure, which is a comprehensive overview of the meningeal immune system from macro to micro. We comprehensively reviewed recent advances in meningeal immunity, particularly the new understanding of the dural sinus and meningeal lymphatics. Moreover, based on the clues from the meningeal immunity, new insights were proposed into the dural arteriovenous fistula (DAVF) pathology, aiming to provide novel ideas for DAVF understanding.

The immune system as a system of relations.

Progress in neuroimmunology established that the nervous and the immune systems are two functionally related physiological systems. Unique sensory and immune receptors enable them to control interactions of the organism with the inner and the outer worlds. Both systems undergo an experience-driven selection process during their ontogeny. They share the same mediators/neurotransmitters and use synapses for intercellular communication. They keep a memory of previous experiences. Immune cells can affect nervous cells, nervous cells can affect immune cells, and they regulate each other. I however argue that the two systems differ by three major points: 1) Unlike the nervous system, the immune system has a loose anatomical structure, in which molecular and cellular events mostly occur at random; 2) The immune system can respond to molecules of the living world whereas the nervous system can respond to phenomena of the physical world; 3) Responses of the immune system act both on the organism and on the stimulus that triggered the response, whereas responses of the nervous system act on the organism only. The nervous and the immune systems therefore appear as two complementary systems of relations that closely work together, and whose reactivities are well-suited to deal with physical and biological stimuli, respectively. Its ability both to adapt the organism to the living world and to adapt the living world to the organism endows the immune system with powerful adaptive properties that enable the organism to live in peace with itself and with other living beings, whether pathogens or commensals.

Standing on the shoulders of mice.

While inbred mice have informed most of what we know about the immune system in the modern era, they have clear limitations with respect to their ability to be informative regarding genetic heterogeneity or microbial influences. They have also not been very predictive as models of human disease or vaccination results. Although there are concerted attempts to compensate for these flaws, the rapid rise of human studies, driven by both technical and conceptual advances, promises to fill in these gaps, as well as provide direct information about human diseases and vaccination responses. Work on human immunity has already provided important additional perspectives on basic immunology such as the importance of clonal deletion to self-tolerance, and while many challenges remain, it seems inevitable that "the human model" will continue to inform us about the immune system and even allow for the discovery of new mechanisms.

The impact of short-term confinement on human innate immunity.

During space missions cosmonauts are exposed to a myriad of distinct stressors such as radiation, overloads, weightlessness, radiation, isolation in artificial environmental conditions, which causes changes in immune system. During space flights it is very difficult to determine the particular factor associated with the observed immunological responses. This makes ground-based experiments examining the effect of each space flight associated factor along of particular value. Determining mechanisms causing alterations in cosmonauts' immunity can lead to potential targets for different countermeasures. In the current article we present the study of the early period of adaptation of human innate immunity of 6 healthy test-subjects, 4 males and 2 females aged 25 through 40, to isolation factors (hypodynamia, psychological stress, artificial environment). We measured multiple parameters characterizing innate immunity status in blood samples at chosen time points before, during and after the mission. In the experiment, highly enhanced cytokine responses were observed upon ex vivo antigen stimulations in comparison to baseline values. For cellular parameters we found multidirectional dynamics with a persistent prevalence of increasing TLRs+ monocytes as well as TLRs expression. Our study provides evidence that even a short-term confinement leads to immune changes in healthy humans that may trigger aberrant immune response.

Age-associated alterations in immune function and inflammation.

Immunosenescence is a term used to describe the age-related changes in the immune system. Immunosenescence is associated with complex alterations and dysregulation of immune function and inflammatory processes. Age-related changes in innate immune responses including alterations in chemotactic, phagocytic, and natural killing functions, impaired antigen presenting capacity, and dysregulated inflammatory response have been described. The most striking and best characterized feature of immunosenescence is the decline in both number and function of T cells. With age there is decreased proliferation, decreased number of antigen-naïve T cells, and increased number of antigen-experienced memory T cells. This decline in naïve T cell population is associated with impaired immunity and reduced response to new or mutated pathogens. While the absolute number of peripheral B cells appears constant with age, changes in B cell functions including reduced antibody production and response and cell memory have been described. However, the main alteration in cell-mediated function that has been reported across all species with aging is those observed in in T cell. These T cell mediated changes have been shown to contribute to increased susceptibility to infection and cancer in older adults. In addition to functional and phenotype alterations in immune cells, studies demonstrate that circulating concentrations of inflammatory mediators in older adults are higher than those of young. This low grade, chronic inflammatory state that occurs in the context of aging has been termed "inflammaging". This review will focus on age-related changes in the immune system including immunosenescence and inflammation as well as the functional consequences of these age-related alterations for the aged.

The Role of the Crosstalk Between Gut Microbiota and Immune Cells in the Pathogenesis and Treatment of Multiple Myeloma.

Around 10% of all hematologic malignancies are classified as multiple myeloma (MM), the second most common malignancy within that group. Although massive progress in developing of new drugs against MM has been made in recent years, MM is still an incurable disease, and every patient eventually has relapse refractory to any known treatment. That is why further and non-conventional research elucidating the role of new factors in MM pathogenesis is needed, facilitating discoveries of the new drugs. One of these factors is the gut microbiota, whose role in health and disease is still being explored. This review presents the continuous changes in the gut microbiota composition during our whole life with a particular focus on its impact on our immune system. Additionally, it mainly focuses on the chronic antigenic stimulation of B-cells as the leading mechanism responsible for MM promotion. The sophisticated interactions between microorganisms colonizing our gut, immune cells (dendritic cells, macrophages, neutrophils, T/B cells, plasma cells), and intestinal epithelial cells will be shown. That article summarizes the current knowledge about the initiation of MM cells, emphasizing the role of microorganisms in that process.

Symbiont-mediated immune priming in animals through an evolutionary lens.

Protective symbionts can defend hosts from parasites through several mechanisms, from direct interference to modulating host immunity, with subsequent effects on host and parasite fitness. While research on symbiont-mediated immune priming (SMIP) has focused on ecological impacts and agriculturally important organisms, the evolutionary implications of SMIP are less clear. Here, we review recent advances made in elucidating the ecological and molecular mechanisms by which SMIP occurs. We draw on current works to discuss the potential for this phenomenon to drive host, parasite, and symbiont evolution. We also suggest approaches that can be used to address questions regarding the impact of immune priming on host-microbe dynamics and population structures. Finally, due to the transient nature of some symbionts involved in SMIP, we discuss what it means to be a protective symbiont from ecological and evolutionary perspectives and how such interactions can affect long-term persistence of the symbiosis.

Differential effects of early or late exposure to prenatal maternal immune activation on mouse embryonic neurodevelopment.

Exposure to maternal immune activation (MIA) in utero is a risk factor for neurodevelopmental and psychiatric disorders. MIA-induced deficits in adolescent and adult offspring have been well characterized; however, less is known about the effects of MIA exposure on embryo development. To address this gap, we performed high-resolution ex vivo MRI to investigate the effects of early (gestational day [GD]9) and late (GD17) MIA exposure on embryo (GD18) brain structure. We identify striking neuroanatomical changes in the embryo brain, particularly in the late-exposed offspring. We further examined the putative neuroanatomical underpinnings of MIA timing in the hippocampus using electron microscopy and identified differential effects due to MIA timing. An increase in apoptotic cell density was observed in the GD9-exposed offspring, while an increase in the density of neurons and glia with ultrastructural features reflective of increased neuroinflammation and oxidative stress was observed in GD17-exposed offspring, particularly in females. Overall, our findings integrate imaging techniques across different scales to identify differential impact of MIA timing on the earliest stages of neurodevelopment.

Influence of exercise and vitamin D on the immune system against Covid-19: an integrative review of current literature.

Respiratory infections of viral origin have become the leading cause of infectious diseases in the world. In 2020, the World Health Organization (WHO) declared a pandemic due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Coronavirus Disease 2019 (Covid-19). The pandemic caused by the new coronavirus has challenged the entire global health system, since Covid-19 has a high rate of morbidity and mortality. The immune response to the virus depends on factors such as age, genetics, nutritional status, physical status, as well as environmental factors. Despite scientific advances, so far, there is still no specific therapy for the disease. Thus, this study aims to analyze the contribution of physical exercise and maintenance and/or supplementation of vitamin D to the strengthening of the immune system against viral infections, among them, Covid-19. Regular practice of moderate-intensity physical activity is responsible for promoting a reduction in the concentrations of pro-inflammatory cytokines (IL-6, TNF-α and IL-1ß), as well as triggering the increase in the production of anti-inflammatory cytokines (IL-4 and IL-10). In addition, hypovitaminosis D predisposes to the development of chronic diseases and infections. Therefore, in patients affected by Covid-19, the maintenance of vitamin D levels contributes significantly to the 0prevention of the cytokine storm. Thus, the association between maintaining vitamin D levels and performing moderate-intensity physical exercise is responsible for strengthening the immune system and, therefore, triggering a defense mechanism against infections by intracellular microorganisms, in which SARS -CoV-2.

Caloric restriction in humans reveals immunometabolic regulators of health span.

The extension of life span driven by 40% caloric restriction (CR) in rodents causes trade-offs in growth, reproduction, and immune defense that make it difficult to identify therapeutically relevant CR-mimetic targets. We report that about 14% CR for 2 years in healthy humans improved thymopoiesis and was correlated with mobilization of intrathymic ectopic lipid. CR-induced transcriptional reprogramming in adipose tissue implicated pathways regulating mitochondrial bioenergetics, anti-inflammatory responses, and longevity. Expression of the gene Pla2g7 encoding platelet activating factor acetyl hydrolase (PLA2G7) is inhibited in humans undergoing CR. Deletion of Pla2g7 in mice showed decreased thymic lipoatrophy, protection against age-related inflammation, lowered NLRP3 inflammasome activation, and improved metabolic health. Therefore, the reduction of PLA2G7 may mediate the immunometabolic effects of CR and could potentially be harnessed to lower inflammation and extend the health span.

Mediterranean Diet, Microbiota and Immunity.

It is well established that the diet, among other external influencing factors, also known as the exposome, has a key role in the prevention and management of different diseases [...].

Cells respond to space microgravity through cytoskeleton reorganization.

Decades of spaceflight studies have provided abundant evidence that individual cells in vitro are capable of sensing space microgravity and responding with cellular changes both structurally and functionally. However, how microgravity is perceived, transmitted, and converted to biochemical signals by single cells remains unrevealed. Here in this review, over 40 cellular biology studies of real space fights were summarized. Studies on cells of the musculoskeletal system, cardiovascular system, and immune system were covered. Among all the reported cellular changes in response to space microgravity, cytoskeleton (CSK) reorganization emerges as a key indicator. Based on the evidence of CSK reorganization from space flight research, a possible mechanism from the standpoint of "cellular mechanical equilibrium" is proposed for the explanation of cellular response to space microgravity. Cytoskeletal equilibrium is broken by the gravitational change from ground to space and is followed by cellular morphological changes, cell mechanical properties changes, extracellular matrix reorganization, as well as signaling pathway activation/inactivation, all of which ultimately lead to the cell functional changes in space microgravity.