P2X receptor agonist enhances tumor-specific CTL responses through CD70+ DC-mediated Th17 induction

Extracellular adenosine triphosphate skews the T helper cell balance and enhances neutrophil activation in mice with food allergies

Exposure to food allergens elicits fast changes in the intestinal microenvironment, which guides the development of allergic reactions. Investigating the key information about these changes may help in better understanding food allergies. In this research, we explored the relationship between a food allergy and extracellular adenosine triphosphate (ATP), a danger molecule that has been proved to regulate the onset of allergic asthma and dermatitis but has not been studied in food allergies, by developing a unique animal model through allergen-containing diet feeding. After consuming an allergen-containing diet for 7 days, the allergic mice exhibited severe enteritis with elevated luminal ATP levels. The dysregulated luminal ATP worsened food-induced enteritis by enhancing Th17 cell responses and increasing mucosal neutrophil accumulation. In vitro experiments demonstrated that ATP intervention facilitated Th17 cell differentiation and neutrophil activation. In addition, the diet-induced allergy showed noticeable gut dysbiosis, characterized by decreased microbial diversity and increased diet-specific microbiota signatures. As the first, we show that food-induced enteritis is associated with an elevated concentration of luminal ATP. The dysregulated extracellular ATP exacerbated the enteritis of mice to a food challenge by manipulating intestinal Th17 cells and neutrophils.

The P2X7 receptor in mucosal adaptive immunity

The P2X7 receptor (P2X7R) is a widely distributed cation channel activated by extracellular ATP (eATP) with exclusive peculiarities with respect to other P2XRs. In recent years, P2X7R has been shown to regulate the adaptive immune response by conditioning T cell signaling and activation as well as polarization, lineage stability, cell death, and function in tissues. Here we revise experimental observations in this field, with a focus on adaptive immunity at mucosal sites, particularly in the gut, where eATP is hypothesized to act in the reciprocal conditioning of the host immune system and commensal microbiota to promote mutualism. The importance of P2X7R activity in the intestine is consistent with the transcriptional upregulation of P2xr7 gene by retinoic acid, a metabolite playing a key role in mucosal immunity. We emphasize the function of the eATP/P2X7R axis in controlling T follicular helper (Tfh) cell in the gut-associated lymphoid tissue (GALT) and, consequently, T-dependent secretory IgA (SIgA), with a focus on high-affinity SIgA-mediated protection from enteropathogens and shaping of a beneficial microbiota for the host.

Alterations of the gut microbial community structure modulates the Th17 cells response in a rat model of asphyxial cardiac arrest

Th17 cells triggered inflammation is a critical element in cerebral ischemic injury, and the gut microbiota intricately impacts T lymphocytes. Nevertheless, it remains unclear whether the gut microbiota involves in cardiac arrest/cardiopulmonary resuscitation (CA/CPR) induced-brain injury through Th17 cells. The present study investigated the interaction between gut microbiota and Th17 cells in a rat model. We observed that CA/CPR induced the alterations of the gut microbial community structure, and elevated the level of IL-17 in the serum, and a slight infiltration of Th17 cells into the brain. The Th17 cells were increased significantly in the peripheral blood, 28.33 ± 6.18% of these Th17 cells were derived from the Peyer's patches of small intestine. Furthermore, fecal microbiota transplantation (FMT) from rats with CA/CPR induced Th17 cell response, promoting hippocampal cell apoptosis and declining learning ability and memory in recipient rats. Taken together, CA/CPR-induced alterations of the gut microbial community structure stimulated Th17 cell response which aggravated brain injury.

Mesenchymal Stromal Cells-Derived Extracellular Vesicles Regulate Dendritic Cell Functions in Dry Eye Disease

We explored the therapeutic efficacy of Mesenchymal stromal cells-derived extracellular vesicles (MSC-EVs) and its inhibition of the functions of dendritic cells (DCs) in dry eye disease (DED). MSC-EVs were isolated from the culture supernatants of mesenchymal stromal cells (MSCs) and characterized. In vitro, human corneal epithelial cells (HCECs) were cultured in hyperosmotic medium to simulate the DED hyperosmotic environment and treated with MSC-EVs. Cell viability was assessed, and the expression of inflammatory cytokines was quantified. Next, we induced DED in female C57BL/6 mice and divided the mice into groups treated with either MSC-EVs or phosphate buffer solution (PBS) eye drops. Disease severity was assessed; mRNA expression of inflammatory cytokines was analyzed by RT-PCR; and Th17 cells were detected by flow cytometry. Lastly, we evaluated DCs by immunofluorescence and flow cytometric analysis to assess its amounts and maturation. MSC-EVs showed protective effects on HCECs under hyperosmotic stress in vitro, suppressing the expression of inflammatory cytokines. In vivo, mice topically treated with MSC-Evs presented reduced DED disease severity compared to PBS-treated mice. MSC-Evs downregulated the expression of inflammatory cytokines, including TNF-α, IL-6, and IL-1β, as well as the frequency of Th17 cells. Further investigation showed that MSC-EVs suppressed the increase of amounts and the maturation of DCs in DED. Changes of morphological characters of DCs were also inhibited by MSC-EVs. Our study revealed that MSC-EVs suppressed ocular surface inflammation by inhibiting DCs activation-mediated Th17 immune responses, explicating the therapeutic potential of MSC-EVs in DED and other ocular surface diseases.

P2 Receptors: Novel Disease Markers and Metabolic Checkpoints in Immune Cells

Extracellular ATP (eATP) and P2 receptors are novel emerging regulators of T-lymphocyte responses. Cellular ATP is released via multiple pathways and accumulates at sites of tissue damage and inflammation. P2 receptor expression and function are affected by numerous single nucleotide polymorphisms (SNPs) associated with diverse disease conditions. Stimulation by released nucleotides (purinergic signalling) modulates several T-lymphocyte functions, among which energy metabolism. Energy metabolism, whether oxidative or glycolytic, in turn deeply affects T-cell activation, differentiation and effector responses. Specific P2R subtypes, among which the P2X7 receptor (P2X7R), are either up- or down-regulated during T-cell activation and differentiation; thus, they can be considered indexes of activation/quiescence, reporters of T-cell metabolic status and, in principle, markers of immune-mediated disease conditions.