Characterization of the immune regulatory property of CD22+ CD9+ B cells

The Impact of FBN1-α5β1 Axis in Fibro/Adipogenic Progenitor Cells (FAPCD9-) on Intramuscular Fat Content in Pigs

Intramuscular fat (IMF) plays a crucial role in enhancing meat quality, enriching meat flavor, and overall improving palatability. In this study, Single-cell RNA sequencing was employed to analyze the longissimus dorsi (LD) obtained from Guangdong small-ear spotted pigs (GDSS, with high IMF) and Yorkshire pigs (YK, with low IMF). GDSS had significantly more Fibro/Adipogenic Progenitor (FAPs), in which the CD9 negative FAPs (FAPCD9-) having adipogenic potential, as demonstrated by in vitro assays using cells originated from mouse muscle. On the other hand, Yorkshire had more fibro-inflammatory progenitors (FIPs, marked with FAPCD9+), presenting higher expression of the FBN1-Integrin α5β1. FBN1-Integrin α5β1 could inhibit insulin signaling in FAPCD9-, suppressing adipogenic differentiation. Our results demonstrated that fat-type pigs possess a greater number of FAPCD9-, which are the exclusive cells in muscle capable of differentiating into adipocytes. Moreover, lean-type pigs exhibit higher expression of FBN1-Integrin α5β1 axis, which inhibits adipocyte differentiation. These results appropriately explain the observed higher IMF content in fat-type pigs.

The elevation of plasma galectin-9 levels in patients with psoriasis and its associations with inflammatory and immune checkpoint molecules in skin tissues

Psoriasis is a chronic, immune-mediated disorder that mainly affects the skin, with an estimated global prevalence of 2-3%. Galectin-9 (Gal-9) is a β-galactoside-binding lectin capable of promoting or suppressing the progression of infectious and immune-mediated diseases. Here, we determined if the expression of Gal-9 is observed in psoriasis. Gal-9 levels were measured in plasma of psoriasis (n = 62) and healthy control (HC) (n = 31) using an enzyme-linked immunosorbent assay. In addition, skin samples from seven patients were screened for RNA transcriptomes and the expression of Gal-9 was compared with inflammatory, immune checkpoint molecules (ICMs) and Foxp3. The plasma Gal-9 levels in patients with psoriasis were significantly higher (841 pg/mL) than in HCs (617 pg/mL) (P < 0.0001) and were associated with white blood cell numbers, eosinophils (%) and alanine transaminase. The levels of inflammatory molecules IL-36B, IL-17RA, IL-6R, IL-10, IRF8, TGFb1, and IL-37, and those of ICMs of Tim-3, CTLA-4, CD86, CD80, PD-1LG2, CLEC4G, and Foxp3 were significantly correlated with Gal-9 (LGALS9) in skin. However, HMGB1, CD44, CEACAM1 and PDL1-known to be associated with a variety of Gal-9 biological functions were not correlated with LGALS9. Thus, it is likely that Gal-9 expression affects the disease state of PS.

Galectin-9 in synergy with NF-κB inhibition restores immune regulatory capability in dendritic cells of subjects with food allergy

The pathogenesis of immune tolerance disruption is not fully understood. Galectin-9 (Gal9) has immune regulatory functions. The objective of the present study is to assess the role of Gal9 in maintaining immune tolerance. Blood and intestinal biopsies were taken from patients with food allergy (FA). The status of tolerogenic dendritic cells (tDC) and type 1 regulatory T cells (Tr1 cells) in the samples was evaluated and used as representative parameters of immune tolerance. An FA mouse model was established to assess the role of Gal9 in maintaining immune tolerance. We found that peripheral CD11c+ CD5+ CD1d+ tDC frequency was significantly lower in FA patients as compared to health control (HC) subjects. There was no significant change in CD11c+ DC frequency between the FA group and the HC group. The expression of IL-10 in peripheral tDCs was lower in the FA group than that in the HC group. A positive correlation was detected between the serum levels of IL-10 and Gal9. The expression of Gal9 was observed in intestinal biopsies, which was positively correlated with the serum levels of Gal9 as well as serum IL-10 levels. Peripheral Tr1 cells had lower frequencies in the FA group than in the non-FA (Con) group. tDCs demonstrated the ability to generate Tr1 cells, which was weaker in the FA group as compared with the Con group. Exposure of FA tDCs to Gal9 in culture restored the ability to generate Tr1 cells. In summary, the lower frequency of tDC and Tr1 cell of FA patients was associated with the levels of Gal9. The presence of Gal9 restored the capacity of tDC to generate Tr1 cells.

Extracellular Vesicles Derived from Allergen Immunotherapy-Treated Mice Suppressed IL-5 Production from Group 2 Innate Lymphoid Cells

Allergen immunotherapy (AIT), such as subcutaneous immunotherapy (SCIT), is a treatment targeting the causes of allergic diseases. The roles of extracellular vesicles (EVs), bilayer lipid membrane blebs released from all types of cells, in AIT have not been clarified. To examine the roles of EVs in SCIT, it was analyzed whether (1) EVs are phenotypically changed by treatment with SCIT, and (2) EVs derived from SCIT treatment suppress the function of group 2 innate lymphoid cells (ILC2s), which are major cells contributing to type 2 allergic inflammation. As a result, (1) expression of CD9, a canonical EV marker, was highly up-regulated by SCIT in a murine model of asthma; and (2) IL-5 production from ILC2s in vitro was significantly decreased by the addition of serum EVs derived from SCIT-treated but not non-SCIT-treated mice. In conclusion, it was indicated that EVs were transformed by SCIT, changing to a suppressive phenotype of type 2 allergic inflammation.