Moonlighting glyceraldehyde-3-phosphate dehydrogenase of Lactobacillus gasseri inhibits keratinocyte apoptosis and skin inflammation in experimental atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disorder affecting up to 20% of children in developed countries. Although probiotics have shown promise as adjuvant treatments for AD, their mechanisms are not well understood. OBJECTIVE: Building upon our previous studies, we investigated whether Lactobacillus gasseri and its moonlighting glyceraldehyde 3-phosphate dehydrogenase (GAPDH), namely LGp40, could be beneficial in AD management. METHODS: In AD mouse models (SKH and C57BL/6J mice) with ovalbumin (OVA) and Dermatophagoides pteronyssinus (Der p) allergens, aligning with the "outside-in" and "inside-out" hypotheses, we administered L. gasseri orally and LGp40 intraperitoneally to investigate their protective effects. The evaluation involved measuring physiological, pathological, and immune function parameters. To delve deeper into the detailed mechanism of LGp40 protection in AD, additional assays were conducted using human skin keratinocytes (HaCaT) and monocytes (THP1) cell lines. RESULTS: L. gasseri and LGp40 enhanced skin barrier function and increased skin moisture retention. They also led to reduced infiltration of Langerhans cells in the dermis and mitigated skewed Th2 and Th17 immune responses. Moreover, LGp40 inhibited allergen-induced keratinocyte apoptosis through the blockade of the caspase-3 cascade and reduced the NLR family pyrin domain containing 3 (NLRP3) inflammasome in macrophages. These inhibitions were achieved through the activation of the peroxisome proliferator-activated receptor gamma (PPARγ) pathway. CONCLUSION: The results of this study provide a novel insight into the mechanism of action of probiotics in the prevention and treatment for allergic disorders through the moonlighting GAPDH protein.

Oral administration of Lactobacillus delbrueckii subsp. lactis LDL557 attenuates airway inflammation and changes the gut microbiota in a Der p-sensitized mouse model of allergic asthma.

BACKGROUND: Lactic acid bacteria may be used as probiotics to prevent or treat various diseases, and Lactobacillus delbrueckii has an inhibitory effect on the development of atopic diseases. OBJECTIVE: This study explored the effects of L. delbrueckii subsp. lactis strain LDL557 administration on a mouse asthma model resulting from Dermatophoides pteronyssinus (Der p) sensitization and investigated the associated gut microbiota. METHODS: Der p-sensitized and challenged BALB/c mice were orally administered with three different doses of live (low, 107 colony-forming units (CFU); medium, 108 CFU; high, 109 CFU) and heat-killed (109 cells) LDL557 in 200 µL of PBS daily, starting 2 weeks before Der p sensitization and lasting 4 weeks. After the allergen challenge, airway responsiveness to methacholine and the influx of inflammatory cells to the lungs were assessed. The gut microbiome was obtained by sequencing the V3-V4 region of the 16S rRNA gene from mice stool samples. RESULTS: LDL557 in the live (109 CFU) and heat-killed (109 cells) conditions reduced the airway hyper-responsiveness after stimulation with methacholine, inflammatory cell infiltration, and mucus production. These effects were similar to those in groups treated with dexamethasone. No significant change in the gut microbiota was observed after LDL557 treatment, except for the tendency of heat-killed LDL557 to change the gut microbial profile to a greater extent than live LDL557. CONCLUSION: In summary, we found that live and heat-killed LDL557 had the beneficial effect of preventing Der p-induced allergic inflammation in a mouse model of asthma.

Goat Milk Consumption Enhances Innate and Adaptive Immunities and Alleviates Allergen-Induced Airway Inflammation in Offspring Mice.

Goat milk (GM), as compared to cow milk (CM), is easier for humans to digest. It also has antioxidant and anti-inflammatory effects and can improve minor digestive disorders and prevent allergic diseases in infants. It is unclear whether GM consumed in pregnant mothers has any protective effects on allergic diseases in infants. In this experimental study with mice, we found GM feeding enhanced immunoglobulin production, antigen-specific (ovalbumin, OVA) immune responses, and phagocytosis activity. The GM-fed mice had an increasing proportion of CD3+ T lymphocytes in the spleen. Splenocytes isolated from these animals also showed significantly increased production of cytokines IFN-γ and IL-10. More importantly, GM feeding during pregnancy and lactation periods can confer protective activity onto offspring by alleviating the airway inflammation of allergic asthma induced by mite allergens. There was a remarkably different composition of gut microbiota between offspring of pregnant mice fed with water or with milk (GM or CM). There was a greater proportion of beneficial bacterial species, such as Akkermansia muciniphila, Bacteroides eggerthii, and Parabacteroides goldsteinii in the gut microbiota of offspring from GM- or CM-fed pregnant mice compared to the offspring of water-fed pregnant mice. These results suggested that improving the nutrition of pregnant mice can promote immunological maturation and colonization of gut microbiota in offspring. This mother-to-child biological action may provide a protective effect on atopy development and alleviate allergen-induced airway inflammation in offspring.