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Ciliated and non-ciliated mechanosensory cells in invertebrates have intricate cytoskeletal structures that, combined with microtubules, act as a mechanical link between external stimulus and signal processing. As a result, they can perceive forces like touch, cuticle deformation, gravity and sound. Through the expression of antibodies against serotonin (5-HT), calbindin, inducible nitric oxide synthase (iNOS) and a-smooth muscle actin (aSMA), this research aims to investigate mechanosensory cells in the integument of Lumbricus terrestris (Linnaeus, 1758) in an evolutionary perspective. In the epidermis, we discovered isolated mechanosensory cells that were immunopositive to every antibody examined. Our findings improve the knowledge and the evolution of annelid sensory biology adding new insights on the sensory signal transduction and help to better understand the morpho-structural adaptations of invertebrate skin on an evolutionary scale and to give more taxonomic data for species distinction. [ABSTRACT FROM AUTHOR]

The shell of bivalves acts as structural support, defence against predators, stressors, and maintenance of homeostasis. Haemocytes and mantle epithelial cells participate in shell formation. Mantle epithelial cells produce the organic matrix of the shell and are associated with biomineralization because of their proximity to the shell surface and ability to maintain shell deposition ex vivo. Haemocytes play an immunological role and are involved in Ca2+ and CO32- intracellular transport implicated in shell mineralization. This study aims to evaluate the expression of molecules that play key roles in internal defence and the nervous system, in epithelial cells and haemocytes of the outer mantle margin of two species of bivalves, Polititapes aureus Gmelin, 1791 and Cerastoderma glaucum Bruguière, 1789, to highlight their collaborative role in shell formation. Our data show for the first time the presence of serotonin/S100 protein, and TLR2/iNOS colocalization in the haemocytes and mantle epithelial cells of P. aureus and C. glaucum , suggesting that the mantle cells perform their canonical role of sensory and biomineralizing activity, while the haemocytes perform their typical immune function, and their collaboration in shell formation, providing new information on cellular interactions in shell formation and giving more details for taxonomical studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Amphibians are classified into three orders with different morphological characteristics: Anura, Apoda, and Caudata. In this article, the importance of skin for amphibians is discussed as it represents a physical, chemical, immunological, and microbiological barrier to pathogen insult is discussed. Langerhans cells (LCs) are antigen-presenting cells constituting an important component of the immune system in the skin. This study aims to characterize Langerhans cells in the skin of Lithobates catesbeianus (Shaw, 1802), Amphiuma means (Garden, 1821), and Typhlonectes natans (Fischer, 1880) with several antibodies previously used to mark the same cells in other vertebrates. The results showed that the distribution of LCs is very similar in the three amphibian species examined, despite their different habitats. In conclusion, the amphibian dendritic cells are morphologically and immunohistochemically homologous to the LCs of all vertebrates so they can be considered as starting points to better understand the phylogeny of the vertebrate immune system. The amphibian taxon includes three orders that present different morphological characteristics: Anura, Caudata, and Apoda. Their skin has a crucial role: it acts as an immune organ constituting a physical, chemical, immunological, and microbiological barrier to pathogen insult and conducts essential physiological processes. Amphibians have developed specialized features to protect the vulnerable skin barrier, including a glandular network beneath the skin surface that can produce antimicrobial and toxic substances, thus contributing to the defense against pathogens and predators. This study aims to characterize Langerhans cells in the skin of Lithobates catesbeianus (order: Anura; Shaw, 1802), Amphiuma means (order: Caudata; Garden, 1821), and Typhlonectes natans (order: Apoda; Fischer, 1880) with the following antibodies: Langerin/CD207 (c-type lectin), Major Histocompatibility Complex (MHC)II, and Toll-like receptor (TLR)2 (expressed by different types of DCs). Our results showed Langerhans cells positive for Langerin CD/207 in the epidermis of the three species; moreover, some antigen-presenting cells (APCs) in the connective tissue expressed TLR2 and MHCII. The distribution of the Langerhans cells is very similar in the three amphibians examined, despite their different habitats. A greater knowledge of the amphibian immune system could be useful to better understand the phylogeny of vertebrates and to safeguard amphibians from population declines. Furthermore, the similarities between amphibians' and human skin concerning immunological features may be useful in both biology and translational medicine. [ABSTRACT FROM AUTHOR]

During adolescence, parental and peer support and emotional intelligence (EI) may play a protective role against the risk of becoming a victim of bullying. This study aims to assess the role of perceived parental and peer support in promoting individual EI, reducing the risk of victimisation. The sample consisted of 348 Italian middle and high school students. Victimisation risk, perceived parental and peer support, and EI were measured using questionnaires. A cross-sectional study and a Structural Equation Model with latent variables were conducted to assess the mediating role of EI in perceived parental and peer support and victimisation risk. Results indicated that EI fully mediated the association between perceived parent (β =.20, p ≤.001) and peer support (β =.10, p ≤.01) and victimisation risk. These data suggest the need to structure training to promote support in the social and family context to increase students' EI and thus reduce the risk of victimisation among students. [ABSTRACT FROM AUTHOR]

Invertebrates show great diversity in their responses to neural damage. Numerous invertebrate phyla, including gastropods, can replace all or a portion of their nervous systems. Aplysia species have been utilized extensively in toxicology, ecology, and neuroscience because their neurological systems react to bodily harm by releasing trophic substances that can stimulate non-neural tissue regeneration and induce changes in the nervous system. This study aims to assess the putative role of hemocytes of Aplysia depilans (Gmelin, 1791) by analyzing the presence of Toll-like receptor 2, inducible nitric oxide synthetase, and, in particular, vimentin and α-tubulin, molecules potentially implicated in the process of neural regeneration. The results demonstrate that all the aforementioned proteins are present in hemocytes, suggesting their role in the defense response and their possible contribution to the neuronal regeneration process of this gastropod. These data provide deeper insight into the internal defense system of this mollusk. [ABSTRACT FROM AUTHOR]

The introduction of pollutants, such as thiacloprid and benzo[a]pyrene (B[a]P), into the waters of urbanized coastal and estuarine areas through fossil fuel spills, domestic and industrial waste discharges, atmospheric inputs, and continental runoff poses a major threat to the fauna and flora of the aquatic environment and can have a significant impact on the internal defense system of invertebrates such as mussels. Using monoclonal and polyclonal anti-Toll-like receptor 2 (TLR2) and anti-inducible nitric oxide synthetase (iNOS) antibodies for the first time, this work aims to examine hemocytes in the mantle and gills of M. galloprovincialis as biomarkers of thiacloprid and B[a]P pollution and analyze their potential synergistic effect. To pursue this objective, samples were exposed to the pollutants, both individually and simultaneously. Subsequently, oxidative stress biomarkers were evaluated by enzymatic analysis, while tissue changes and the number of hemocytes in the different contaminated groups were assessed via histomorphological and immunohistochemical analyses. Our findings revealed that in comparison to a single exposure, the two pollutants together significantly elevated oxidative stress. Moreover, our data may potentially enhance knowledge on how TLR2 and iNOS work as part of the internal defense system of bivalves. This would help in creating new technologies and strategies, such as biosensors, that are more suitable for managing water pollution, and garnering new details on the condition of the marine ecosystem. [ABSTRACT FROM AUTHOR]

The common goldfish is the most widespread teleosts in the world. Due to its peculiar characteristics, such as the high resistance, easy availability and stabulation, and for its evolutionary characteristics, this fish lends itself to be one of the most used experimental models. This study aimed to characterize the mast cells in the intestine of Carassius auratus using anti‐TLR‐2, anti‐S100, anti‐VIP, anti‐serotonin (5‐HT) and anti‐Piscidin antibodies. The intestine of goldfish, like that of all vertebrates, plays an important role in the immunology of the animal. The gut‐associated lymphoid tissue GALT is an immune component containing several specific cells such as lymphocytes, macrophages and mast cells. In addition, the presence of goblet cells in the intestinal epithelium strengthens the defence system, secreting many cytokines and chemokines and displaying antibacterial properties. Our results show mast cells labelled with antibodies that are highly conserved between fish and mammals, demonstrating an active role of these cells in the immune response. [ABSTRACT FROM AUTHOR]

Metazoans have several mechanisms of internal defense for their survival. The internal defense system evolved alongside the organisms. Annelidae have circulating coelomocytes that perform functions comparable to the phagocytic immune cells of vertebrates. Several studies have shown that these cells are involved in phagocytosis, opsonization, and pathogen recognition processes. Like vertebrate macrophages, these circulating cells that permeate organs from the coelomic cavity capture or encapsulate pathogens, reactive oxygen species (ROS), and nitric oxide (NO). Furthermore, they produce a range of bioactive proteins involved in immune response and perform detoxification functions through their lysosomal system. Coelomocytes can also participate in lithic reactions against target cells and the release of antimicrobial peptides. Our study immunohistochemically identify coelomocytes of Lumbricus terrestris scattered in the epidermal and the connective layer below, both in the longitudinal and in the smooth muscle layer, immunoreactive for TLR2, CD14 and α-Tubulin for the first time. TLR2 and CD14 are not fully colocalized with each other, suggesting that these coelomocytes may belong to two distinct families. The expression of these immune molecules on Annelidae coelomocytes confirms their crucial role in the internal defense system of these Oligochaeta protostomes, suggesting a phylogenetic conservation of these receptors. These data could provide further insights into the understanding of the internal defense system of the Annelida and of the complex mechanisms of the immune system in vertebrates. [ABSTRACT FROM AUTHOR]

The immune system of teleosts offers many ideas to deepen the immune mechanisms and cells in general. The use of zebrafish as an experimental model is increased in recent years, thanks to its genetic and anatomical characteristics. It is known that several natural compounds exert an action on the immune system, boosting it. Spirulina, a non-toxic blue-green alga, has been declared a superfood for its peculiar biological activities. In this study, we test the immunostimulant effect of spirulina on zebrafish liver macrophages by immunohistochemical analysis using optical and confocal microscopy. Our results have shown an increase in the number of macrophages after feeding with spirulina, furthermore, this natural 'superfood' can induce macrophages aggregation. These data not only provide information on the possible effect of this alga as a complementary feed on the immune cells of teleost, but also improve the knowledge of the immune mechanisms of vertebrates. [ABSTRACT FROM AUTHOR]

The amphibious teleost Giant mudskipper (Periophthalmodon schlosseri, Pallas 1770) inhabit muddy plains and Asian mangrove forests. It spends more than 90% of its life outside of the water, using its skin, gills, and buccal-pharyngeal cavity mucosa to breathe in oxygen from the surrounding air. All vertebrates have been found to have mast cells (MCs), which are part of the innate immune system. These cells are mostly found in the mucous membranes of the organs that come in contact with the outside environment. According to their morphology, MCs have distinctive cytoplasmic granules that are released during the degranulation process. Additionally, these cells have antimicrobial peptides (AMPs) that fight a variety of infections. Piscidins, hepcidins, defensins, cathelicidins, and histonic peptides are examples of fish AMPs. Confocal microscopy was used in this study to assess Piscidin1 expression in Giant Mudskipper branchial MCs. Our results demonstrated the presence of MCs in the gills is highly positive for Piscidin1. Additionally, colocalized MCs labeled with TLR2/5-HT and Piscidin1/5-HT supported our data. The expression of Piscidin1 in giant mudskipper MCs highlights the involvement of this peptide in the orchestration of teleost immunity, advancing the knowledge of the defense system of this fish. [ABSTRACT FROM AUTHOR]

Neurodegeneration is a degenerative process characterized by the progressive loss of the structure and function of neurons that involves several immune cells. It is the primary cause of dementia and other several syndromes, known as neurodegenerative diseases. These disorders are age-related and it is estimated that by 2040 there will be approximately 81.1 million people suffering from these diseases. In addition to the traditional pharmacological therapy, in recent years nutraceuticals, naturally based compounds with a broad spectrum of biological effects: anti-aging, antioxidants, hypoglycaemic, hypocholesterolemic, anticancer, anxiolytic, antidepressant, etc., assumed an important role in counteracting these pathologies. In particular, several compounds such as astaxanthin, baicalein, glycyrrhizin, St. John's wort, and Ginkgo biloba L. extracts show particular neuroprotective and immunomodulatory abilities, involving several immune cells and some neurotransmitters that play a critical role in neurodegeneration, making them particularly useful in improving the symptoms and progression of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

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. Highlight how several nutraceuticals may have an immunostimulant and antidepressant effect on Covid-19 symptoms. [ABSTRACT FROM AUTHOR]

Simple Summary: The intestinal epithelium of fish, similar to mammals, consists mainly of enterocytes and goblet cells. Goblet cells play a key role in the secretion of mucus, which, in addition to promoting the digestion of nutrients, is the first protective barrier against bacteria, viruses, and pathogens. Our study aims to evaluate the presence, localization, and co-localization of 5-HT, TLR2, iNOS, and Piscidin1 in goblet cells of the intestine of Eptatretus cirrhatus. The results obtained by confocal microscopy show, for the first time, the positivity of goblet cells to the antibodies tested, suggesting the involvement of these cells in the intestinal immunity of broadgilled hagfish. The fish intestine operates as a complicated interface between the organism and the environment, providing biological and mechanical protections as a result of a viscous layer of mucus released by goblet cells, which serves as a barrier against bacteria, viruses, and other pathogens, and contributes to the functions of the immune system. Therefore, goblet cells have a role in preserving the health of the body by secreting mucus and acting as sentinels. The ancient jawless fish broadgilled hagfish (Eptatretus cirrhatus, Forster, 1801) has a very basic digestive system because it lacks a stomach. By examining the presence, localization, and co-localization of 5-HT, TLR2, iNOS, and Piscidin1, this study intends to provide insight into the potential immune system contributions arranged by the gut goblet cells of broadgilled hagfish. Our results characterize intestinal goblet cells of broadgilled hagfish, for the first time, with the former antibodies, suggesting the hypothesis of conservation of the roles played by these cells also in primitive vertebrates. Moreover, this study deepens the knowledge about the still little-known immune system of hagfish. [ABSTRACT FROM AUTHOR]

Simple Summary: This research aimed to define intestinal DCs from myxines to teleosts by using immunohistochemistry with TLR-2, Langerin/CD207, and MHC II. In particular, we analyzed intestinal DCs in several species of fish phylogenetically organized: Eptatretus cirrhatus (myxines), Scyliorhinus canicula (Chondrichthyes), Polypterus senegalus (Osteichthyes, Brachiopterygii), Lepisosteus oculatus (Osteichthyes, Holostei), and Clarias batrachus (Osteichthyes, Teleostei). The findings show that intestinal DCs and DC-like cells are positive to all the antibodies tested, demonstrating the presence of these cells phylogenetically from myxines to teleosts. These results could improve the state-of-the-art on the evolution of the immune system and the importance of sentinel cells in the body's defense. In addition, we demonstrated with immunohistochemistry the presence of MHC II in myxines (Eptatretus cirrhatus) for the first time. Dendritic cells (DCs) are antigen-presenting cells (APCs) that regulate the beginning of adaptive immune responses. The mechanisms of tolerance to antigens moving through the digestive tract are known to be regulated by intestinal DCs. Agnatha and Gnathostoma are descendants of a common ancestor. The Ostracoderms gave rise to Cyclostomes, whereas the Placoderms gave rise to Chondrichthyes. Sarcopterygii and Actinopterygii are two evolutionary lines of bony fishes. Brachiopterygii and Neopterygii descend from the Actinopterygii. From Neopterygii, Holostei and Teleostei evolved. Using immunohistochemistry with TLR-2, Langerin/CD207, and MHC II, this study aimed to characterize intestinal DCs, from myxines to teleosts. The findings reveal that DCs are positive for the antibodies tested, highlighting the presence of DCs and DC-like cells phylogenetically from myxines, for the first time, to teleosts. These findings may aid in improving the level of knowledge about the immune system's evolution and these sentinel cells, which are crucial to the body's defense. [ABSTRACT FROM AUTHOR]

The immune system is highly dynamic and susceptible to many alterations throughout pregnancy. Since December 2019, a pandemic caused by coronavirus disease 19 (COVID-19) has swept the globe. To contain the spread of COVID-19, immediate measures such as quarantine and isolation were implemented. These containment measures have contributed to exacerbate situations of anxiety and stress, especially in pregnant women, who are already particularly anxious about their condition. Alterations in the psychological state of pregnant women are related to alterations in the immune system, which is more vulnerable under stress. COVID-19 could therefore find fertile soil in these individuals and risk more severe forms. Normally a controlled dietary regimen is followed during pregnancy, but the use of particular vitamins and micronutrients can help counteract depressive-anxiety states and stress, can improve the immune system, and provide an additional weapon in the defense against COVID-19 to bring the pregnancy to fruition. This review aims to gather data on the impact of COVID-19 on the immune system and psychological condition of pregnant women and to assess whether some micronutrients can improve their psychophysical symptoms. [ABSTRACT FROM AUTHOR]

Industrialization has resulted in a massive increase in garbage output, which is frequently discharged or stored in waterways like rivers and seas. Due to their toxicity, durability, bioaccumulation, and biomagnification, heavy metals (such as mercury, cadmium, and lead) have been identified as strong biological poisons. Their presence in the aquatic environment has the potential to affect water quality parameters and aquatic life in general. Teleosts' histopathology provides a sensitive indicator of pollutant-induced stress, because their organs have a central role in the transformation of different active chemical compounds in the aquatic environment. In particular, the gills, kidneys, and liver are placed at the center of toxicological studies. The purpose of this study is to examine the morphological changes caused by heavy metals in the kidney and gills of Boops boops, with a focus on melanomacrophages centers (MMCs) and rodlet cells (RCs) as environmental biomarkers, using histological and histochemical stainings (hematoxylin/eosin, Van Gieson trichrome, Periodic Acid Schiff reaction, and Alcian Blue/PAS 2.5), and immunoperoxidase methods. Our findings show an increase of MMCs and RCs linked to higher exposure to heavy metals, confirming the role of these aggregates and cells as reliable biomarkers of potential aquatic environmental changes reflected in fish fauna. The cytological study of RCs and MMCs could be important in gaining a better understanding of the complicated immune systems of teleosts. [ABSTRACT FROM AUTHOR]

Neurodegenerative diseases afflict a significant percentage of the world's population. The human nervous system is unable to regenerate after an insult, or due to senility, while low vertebrates still exhibit this ability. Comparative neurobiology can increase knowledge about neuronal degeneration and regeneration. Anamni vertebrates retain the ability to regenerate up to large areas of the nervous system. The regenerative ability of central nervous system components depends on the phylogenetic distance between classes of vertebrates. It decreases during evolution. Teleosts can skilfully regenerate brain, spinal cord and retina. Amphibians and reptiles can only regenerate certain areas; spinal cord regeneration in reptiles is limited to axonal regrowth. Retina regeneration is possible in bird embryo but not in the adult. In this review, we analyse how the regeneration of neurons occurs in different classes of vertebrates, and how the study of these mechanisms could be applied to the search for new therapies for neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Psoriasis is one of the most widespread chronic inflammatory skin diseases, affecting about 2%–3% of the worldwide adult population. The pathogenesis of this disease is quite complex, but an interaction between genetic and environmental factors has been recognized with an essential modulation of inflammatory and immune responses in affected patients. Psoriatic plaques generally represent the clinical psoriatic feature resulting from an abnormal proliferation and differentiation of keratinocytes, which cause dermal hyperplasia, skin infiltration of immune cells, and increased capillarity. Some scientific pieces of evidence have reported that psychological stress may play a key role in psoriasis, and the disease itself may cause stress conditions in patients, thus reproducing a vicious cycle. The present review aims at examining immune cell involvement in psoriasis and the relationship of depression and stress in its pathogenesis and development. In addition, this review contains a focus on the possible use of natural products, thus pointing out their mechanism of action in order to counteract clinical and psychological symptoms. [ABSTRACT FROM AUTHOR]

The article focuses on the relationship between telocytes (TCs) and immune cells, particularly the expression of S100 protein, in Inflammatory Bowel Disease (IBD), finding that TCs are involved in the inflammatory response, and their presence decreases in fibrotic areas correlating.

The use of polyphenols as adjuvants in lowering risk factors for various debilitating diseases has been investigated in recent years due to their possible antioxidant action. Polyphenols represent a fascinating and relatively new subject of research in nutraceuticals and nutrition, with interest rapidly expanding since they can help maintain health by controlling metabolism, weight, chronic diseases, and cell proliferation. Resveratrol is a phenolic compound found mostly in the pulp, peels, seeds, and stems of red grapes. It has a wide variety of biological actions that can be used to prevent the beginning of various diseases or manage their symptoms. Resveratrol can influence multiple inflammatory and non-inflammatory responses, protecting organs and tissues, thanks to its interaction with immune cells and its activity on SIRT1. This compound has anti-inflammatory, antioxidant, anti-apoptotic, neuroprotective, cardioprotective, anticancer, and antiviral properties, making it a potential adjunct to traditional pharmaceutical therapy in public health. This review aims to provide a comprehensive analysis of resveratrol in terms of active biological effects and mechanism of action in modifying the immune cellular response to promote human psychophysical health. [ABSTRACT FROM AUTHOR]