Metabolic pathways in immune senescence and inflammaging: Novel therapeutic strategy for chronic inflammatory lung diseases. An EAACI position paper from the Task Force for Immunopharmacology.

The accumulation of senescent cells drives inflammaging and increases morbidity of chronic inflammatory lung diseases. Immune responses are built upon dynamic changes in cell metabolism that supply energy and substrates for cell proliferation, differentiation, and activation. Metabolic changes imposed by environmental stress and inflammation on immune cells and tissue microenvironment are thus chiefly involved in the pathophysiology of allergic and other immune-driven diseases. Altered cell metabolism is also a hallmark of cell senescence, a condition characterized by loss of proliferative activity in cells that remain metabolically active. Accelerated senescence can be triggered by acute or chronic stress and inflammatory responses. In contrast, replicative senescence occurs as part of the physiological aging process and has protective roles in cancer surveillance and wound healing. Importantly, cell senescence can also change or hamper response to diverse therapeutic treatments. Understanding the metabolic pathways of senescence in immune and structural cells is therefore critical to detect, prevent, or revert detrimental aspects of senescence-related immunopathology, by developing specific diagnostics and targeted therapies. In this paper, we review the main changes and metabolic alterations occurring in senescent immune cells (macrophages, B cells, T cells). Subsequently, we present the metabolic footprints described in translational studies in patients with chronic asthma and chronic obstructive pulmonary disease (COPD), and review the ongoing preclinical studies and clinical trials of therapeutic approaches aiming at targeting metabolic pathways to antagonize pathological senescence. Because this is a recently emerging field in allergy and clinical immunology, a better understanding of the metabolic profile of the complex landscape of cell senescence is needed. The progress achieved so far is already providing opportunities for new therapies, as well as for strategies aimed at disease prevention and supporting healthy aging.

Oral myeloid cells uptake allergoids coupled to mannan driving Th1/Treg responses upon sublingual delivery in mice.

BACKGROUND: Polymerized allergoids coupled to nonoxidized mannan (PM-allergoids) may represent novel vaccines targeting dendritic cells (DCs). PM-allergoids are better captured by DCs than native allergens and favor Th1/Treg cell responses upon subcutaneous injection. Herein we have studied in mice the in vivo immunogenicity of PM-allergoids administered sublingually in comparison with native allergens. METHODS: Three immunization protocols (4-8 weeks long) were used in Balb/c mice. Serum antibody levels were tested by ELISA. Cell responses (proliferation, cytokines, and Tregs) were assayed by flow cytometry in spleen and lymph nodes (LNs). Allergen uptake was measured by flow cytometry in myeloid sublingual cells. RESULTS: A quick antibody response and higher IgG2a/IgE ratio were observed with PM-allergoids. Moreover, stronger specific proliferative responses were seen in both submandibular LNs and spleen cells assayed in vitro. This was accompanied by a higher IFNγ/IL-4 ratio with a quick IL-10 production by submandibular LN cells. An increase in CD4+ CD25high FOXP3+ Treg cells was detected in LNs and spleen of mice treated with PM-allergoids. These allergoids were better captured than native allergens by antigen-presenting (CD45+ MHC-II+ ) cells obtained from the sublingual mucosa, including DCs (CD11b+ ) and macrophages (CD64+ ). Importantly, all the differential effects induced by PM-allergoids were abolished when using oxidized instead of nonoxidized PM-allergoids. CONCLUSION: Our results demonstrate for the first time that PM-allergoids administered through the sublingual route promote the generation of Th1 and FOXP3+ Treg cells in a greater extent than native allergens by mechanisms that might well involve their better uptake by oral antigen-presenting cells.

MV140, a sublingual polyvalent bacterial preparation to treat recurrent urinary tract infections, licenses human dendritic cells for generating Th1, Th17, and IL-10 responses via Syk and MyD88.

Recurrent urinary tract infections (RUTIs) are one of the most common bacterial infectious diseases, especially in women. Antibiotics remain the mainstay of treatment, but their overuse is associated with antibiotic-resistant infections and deleterious effects in the microbiota. Therefore, alternative approaches are fully demanded. Sublingual immunization with MV140 (Uromune), a polyvalent bacterial preparation (PBP) of whole heat-inactivated bacteria, demonstrated clinical efficacy for the treatment of RUTIs, but the involved immunological mechanisms remain unknown. Herein, we demonstrated that MV140 endorses human dendritic cells (DCs) with the capacity to generate Th1/Th17 and IL-10-producing T cells by mechanisms depending on spleen tyrosine kinase (Syk)- and myeloid differentiation primary response gene 88 (MyD88)-mediated pathways. MV140-induced activation of nuclear factor κB (NF-κB) and p38 in human DCs is essential for the generated Th1/Th17 and IL-10 immune responses whereas c-Jun N-terminal Kinase (JNK) and extracellular-signal regulated kinase (ERK) contribute to Th1 and IL-10 responses, respectively. Sublingual immunization of BALB/c mice with MV140 also induces potent systemic Th1/Th17 and IL-10 responses in vivo. We uncover immunological mechanisms underlying the way of action of MV140, which might well also contribute to understand the rational use of specific PBPs in other clinical conditions with potential high risk of recurrent infections.