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Alzheimer's disease (AD) is one of the most prevalent forms of neurodegenerative disorders. Previously, we have shown that in vivo administration of an IL-17 neutralizing antibody (IL-17Ab) rescues amyloid-β-induced neuro-inflammation and memory impairment, demonstrating the pivotal role of IL-17 in AD-derived cognitive deficit. Recently, AD has been recognized as a more intriguing pathology affecting vascular network and platelet function. However, not much is known about peripheral vascular inflammation and how pro-inflammatory circulating cells/mediators could affect peripheral vessels' function. This study aimed to evaluate whether IL-17Ab treatment could also impact peripheral AD features, such as systemic inflammation, peripheral vascular dysfunction, and related pro-thrombotic state in a non-genetic mouse model of AD. Mice were injected intracerebroventricularly with Aβ1-42 peptide (3μg/3μl). To evaluate the systemic/peripheral protective profile of IL-17Ab, we used an intranasal administration of IL-17Ab (1μg/10μl) at 5, 12, and 19 days after Aβ1-42 injection. Circulating Th17/Treg cells and related cyto-chemokines, haematological parameters, vascular/endothelial reactivity, platelets and coagulation function in mice were evaluated. IL-17Ab treatment ameliorates the systemic/peripheral inflammation, immunological perturbance, vascular/endothelial impairment and pro-thrombotic state, suggesting a key role for this cytokine in fostering inflammatory processes that characterize the multifaced aspects of AD.

Adaptive immunity relies on the efficient recruitment of T cells from the blood into peripheral tissues. However, the current understanding of factor(s) coordinating these events is incomplete. Previous studies on galectin-9 (Gal-9), have proposed a functionally significant role for this lectin in mediating leukocyte adhesion and transmigration. However, very little is known about its function in T cell migration. Here, we have investigated the role of the Gal-9 on the migration behaviour of both human primary CD4+ and CD8+ T cells. Our data indicate that Gal-9 supports both CD4+ and CD8+ T cell adhesion and transmigration in a glycan dependent manner, inducing L-selectin shedding and upregulation of LFA-1 and CXCR4 expression. Additionally, when immobilized, Gal-9 promoted capture and firm adhesion of T cells under flow, in a glycan and integrin-dependent manner. Using an in vivo model, dorsal air pouch, we found that Gal-9 deficient mice display impaired leukocyte trafficking, with a reduction in pro-inflammatory cytokines/chemokines generated locally. Furthermore, we also demonstrate that Gal-9 inhibits the chemotactic function of CXCL12 through direct binding. In conclusion, our study characterises, for the first time, the capture, adhesion, and migration behaviour of CD4+ and CD8+ T cells to immobilised /endothelial presented Gal-9, under static and physiological flow conditions. We also demonstrate the differential binding characteristics of Gal-9 to T cell subtypes, which could be of potential therapeutic significance, particularly in the treatment of inflammatory-based diseases, given Gal-9 ability to promote apoptosis in pathogenic T cell subsets.

Transgenic mice expressing a rearranged T cell receptor (TCR)-αβ prematurely at the double-negative stage develop an abnormal population of peripheral T cells that lack CD4 and CD8 expression and are hyper-reactive to anti-TCR antibody stimulation. One such example is the HY-TCR transgenic mice. These mice express a TCR transgenic specific for the HY antigen that is expressed in male but not in female mice. As a result, male mice have an abnormal population of HY(+)/CD4(-)8(-) or HY(+)/CD4(-)CD8(low) T cells that are much lower in female mice. In this study, we investigated the potential patho/physiological function of these cells in vivo using a model of delayed-type hypersensitivity (DTH) reaction: the λ-carrageenan-induced paw edema. Interestingly, while both male and female HY-TCR mice develop a classical biphasic inflammatory response to λ-carrageenan, the degree of inflammation in the former was much higher than that in the latter. This was accompanied by a selective expansion of HY(+)/CD4(-)8(-) and HY(+)/CD4(-)CD8(low) T cells in male mice and by a markedly increased production of typical DTH cytokines compared with cells from female mice. These results were specific since analysis of the inflammatory response of HY-TCR transgenic mice subjected to zymosan-induced peritonitis showed no differences between male and female mice. Together, these findings provide novel evidence for the pathological role of self-reactive CD4(-)CD8(-) T cells, previously described in several autoimmune strains and recently identified in patients suffering from autoimmune diseases such as systemic lupus erythematosus.

Inflammation is a complex biological response to injury as a result of different stimuli such as pathogens, damaged cells, or irritants. Nowadays, the commercially approved anti-inflammatory drugs are represented by nonsteroidal anti-inflammatory drugs (NSAID), glucocorticoids (SAID), and in some cases immunosuppressant and/or biological drugs. These agents are effective for the relief of the main inflammatory symptoms. However, they induce severe side effects, whereas most of them are inadequate for chronic use. Starting from these premises, the demand of new effective and safely anti-inflammatory drugs has furthered research into new therapeutic approaches. The recent and emerging scientific community slant is oriented to the herbal medicines that could represent a treasure for the discovery of new active compounds and for the development of new drugs and potentially useful therapeutic agents. The articles contained in this special issue include both reviews and basic scientific studies focused on characterizing the molecular mechanisms of the inflammatory process in humans and also in animal models. In particular, on this special issue the attention on the role of proinflammatory mediators and pathways such as IL-1, IL-6, mPGES-1, and NF-B had been pointed out (“Moringa oleifera Flower Extract Suppresses the Activation of Inflammatory Mediators in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages via NF-κB Pathway” by W. S. Tan et al. and “Downregulation of mPGES-1 Expression via EGR1 Plays an Important Role in Inhibition of Caffeine on PGE2 Synthesis of HBx(+) Hepatocytes” by Y. Ma et al. and “Anti-Inflammatory Effect of 1,3,5,7-Tetrahydroxy-8-isoprenylxanthone Isolated from Twigs of Garcinia esculenta on Stimulated Macrophage” by D.-D. Zhang et al.). Moreover, this special issue has highlighted the importance of some mechanism and strategy involved in inflammatory bowel disease and experimental model of osteoarthritis (“Botanical Drugs as an Emerging Strategy in Inflammatory Bowel Disease: A Review” by F. Algieri et al. and “Therapeutic Effect of Chenodeoxycholic Acid in an Experimental Rabbit Model of Osteoarthritis” by Z. Yan et al.). Finally, interesting contributions regarding the anti-inflammatory activity of marine diterpenoids and leishmaniasis inflammatory response have been successfully submitted to this special issue (“Marine Diterpenoids as Potential Anti-Inflammatory Agents” by Y. Gonzalez et al. and “Natural Products: Insights into Leishmaniasis Inflammatory Response” by I. A. Rodrigues et al.). We hope that this special issue will stimulate the interest of the scientific community involved in studying the effects of natural products/compounds on different fields of interests such as inflammation and pain. The papers published here will surely contribute to proposing new additional insights into the mechanism of several conditions as well as to suggesting new diagnostic alternatives and therapeutic targets in widespread pathologies. The discovery of the new is, as always, anchored to the recourse of the old.