Maternal antibiotic exposure enhances ILC2 activation in neonates via downregulation of IFN1 signaling

Maternal OM-85 administration alleviates offspring allergic airway inflammation by downregulating IL-33/ILC2 axis

BACKGROUND

Type 2 innate lymphoid cells (ILC2s) are essential for maintaining immune regulation and promoting tissue homeostasis in allergic asthma. How the development of gut microbiota on neonatal ILC2s influences allergic airway inflammation remains unclear. Here we focus on offspring ILC2 development in the context of alterations in maternal gut microbiota.

METHODS

C57BL/6 maternal mice were gavaged with OM-85 during pregnancy and/or lactation, ILC2-driven allergic airway inflammation in the OVA-sensitized adult offspring was observed. ILC2 development in offspring early life were investigated using recombinant (r)IL-33, rIL-25 and Bromodeoxyuridine in the vivo experiments. Further ILC2 promoting factors- IL-33 and IL-25 production in offspring early life were analysed. Finally, we examined the changes in gut microbiota and its metabolites in both dams and pups, and explored the effects of short-chain fatty acids (SCFAs) on IL-33 expression and secretion.

RESULTS

Maternal OM-85 administration restrained ILC2-driven allergic airway inflammation in the OVA-sensitized adult offspring. During ILC2 development in offspring early life, maternal OM-85 administration suppressed IL-33 and IL-25 production to inhibit ILC2 expansion and ILC2 responsiveness to alarmins, and infantile ILC2s could persist into adulthood. Maternal OM-85 administration increased SCFAs in breast milk and SCFA-producing gut probiotics (predominant Bacteroides and Blautia) in offspring, especially during pregnancy and lactation. SCFAs down-regulated IL-33 expression and reduced IL-33 secretion by inhibited gasdermin D (GSDMD) formation.

CONCLUSION

Maternal OM-85 administration restrains ILC2-driven allergic airway inflammation in adult offspring by increasing offspring intestinal SCFAs to modulate ILC2 development at an early stage, demonstrating that the transgenerational effects of maternal OM-85 exposure on offspring innate immunity.

Maternal exercise prevents metabolic disorders in offspring mice through SERPINA3C

Maternal exercise can improve the metabolic health of the offspring. However, the molecular mechanisms underlying the beneficial effects of maternal exercise on the offspring remain unclear. Here, we show that maternal exercise during pregnancy alleviates high-fat diet (HFD)-induced adipose inflammation and glucose intolerance in offspring mice, accompanied by upregulation of the adipokine serine protease inhibitor A3C (SERPINA3C) both in maternal adipose tissues and the fetal circulation. Adipose SERPINA3C knockdown impairs, but its overexpression in dams mimics, maternal exercise-mediated metabolic benefits in HFD-fed offspring. Maternal SERPINA3C is transported into the fetal circulation and promotes Krüppel-like factor 4 (Klf4) gene promoter demethylation in fetal preadipocytes to increase KLF4 expression, which inhibits adipose inflammation in HFD-fed offspring mice. The SERPINA3C-cathepsin G-integrin β1 axis activates phosphatidylinositol 3-kinase signalling in preadipocytes. This promotes nuclear translocation of the p110β subunit to generate phosphatidylinositol 3,4,5-trisphosphate (PIP3) in the nucleus. O-linked β-N-acetylglucosamine (O-GlcNAc) transferase then binds to PIP3 to promote ten-eleven translocation methylcytosine dioxygenase 1 (TET1) O-GlcNAcylation, thereby enhancing TET1 activity to facilitate Klf4 gene promoter demethylation. These results provide mechanistic insights into maternal exercise-mediated improvement of offspring metabolism.

Shaping oral and intestinal microbiota and the immune system during the first 1,000 days of life

The first 1, 000 days of life, from the fetal stage of a woman's pregnancy to 2 years of age after the baby is born, is a critical period for microbial colonization of the body and development of the immune system. The immune system and microbiota exhibit great plasticity at this stage and play a crucial role in subsequent development and future health. Two-way communication and interaction between immune system and microbiota is helpful to maintain human microecological balance and immune homeostasis. Currently, there is a growing interest in the important role of the microbiota in the newborn, and it is believed that the absence or dysbiosis of human commensal microbiota early in life can have lasting health consequences. Thus, this paper summarizes research advances in the establishment of the oral and intestinal microbiome and immune system in early life, emphasizing the substantial impact of microbiota diversity in the prenatal and early postnatal periods, and summarizes that maternal microbes, mode of delivery, feeding practices, antibiotics, probiotics, and the environment shape the oral and intestinal microbiota of infants in the first 1, 000 days of life and their association with the immune system.

Maternal asthma imprints fetal lung ILC2s via glucocorticoid signaling leading to worsened allergic airway inflammation in murine adult offspring

The root of asthma can be linked to early life, with prenatal environments influencing risk. We investigate the effects of maternal asthma on the offspring's lungs during fetal and adult life. Adult offspring of asthmatic mothers show an increase in lung group 2 innate lymphoid cell (ILC2) number and function with allergen-induced lung inflammation. Offspring of asthmatic mothers show phenotypic alteration of their lung ILC2s during fetal life, with increased expression of genes related to activation and glucocorticoid signaling. Furthermore, these offspring carry overlapping chromatin-accessible altered regions, including glucocorticoid receptor-binding regions in their lung ILC2s both at the fetal stage and adulthood, suggesting persistent prenatal epigenetic changes. Moreover, maternal exposure to glucocorticoids has similar effects on fetal lung ILC2s and contributes to allergen-induced lung inflammation during adulthood. Thus, asthma during pregnancy may have long-term effects on lung ILC2s in the offspring from the embryonic period, contributing to an increased risk of developing asthma.

Electroacupuncture may protect pulmonary dysplasia in offspring with perinatal nicotine exposure by altering maternal gut microbiota and metabolites

Background

Perinatal nicotine exposure (PNE) induces pulmonary dysplasia in offspring and it increases the risk of respiratory diseases both in offspring and across generations. The maternal gut microbiota and its metabolites, such as short-chain fatty acids (SCFAs), can regulate fetal lung development and are susceptible to nicotine exposure. Therefore, modulation of PNE-induced changes in maternal gut microbiota and SCFAs may prevent the occurrence of pulmonary dysplasia in offspring.

Objective

Our previous studies demonstrated that electroacupuncture (EA) ameliorated PNE-induced impairment in offspring lung development. To further our study, we aimed to determine whether the protective effect of EA is associated with the modulation of changes in maternal gut microbiota and SCFAs.

Methods

We observed changes in maternal gut microbiota and serum SCFA levels in both mother and offspring after EA treatment using a PNE rat model. Furthermore, using broad-spectrum antibiotics, we established a pseudo-germ-free PNE rat model to explore whether EA can protect offspring's pulmonary function and lung morphology in the presence of depleted maternal gut microbiota.

Results

Our study revealed that EA increased the community richness (Sobs index) of perinatal nicotine-exposed maternal gut microbiota and the abundance of beneficial bacteria (RF39, Clostridia, Oscillospirales, etc.). This was accompanied by an upregulated serum levels of acetate, butyrate, and total SCFAs in both mother and offspring rats, as well as stimulated expression of SCFA receptors (GPR41 and GPR43) in the lung tissue of offspring rats. However, the beneficial effects of EA on offspring pulmonary function (FVC, PEF, PIF, and Cdyn) and lung morphology (alveolar number and MLI) were lost after maternal gut microbiota depletion.

Conclusion

These findings suggest that EA may exert its therapeutic effects on PNE-induced lung phenotype by altering maternal gut microbiota. The likely mechanism involves the associated improvement in serum SCFA levels in both mother and offspring, as well as the upregulation of SCFA receptors in the lung tissue of offspring.

Butyrate protects the intestinal barrier by upregulating Fut2 expression via MEK4-JNK signaling pathway activation

BACKGROUND

Necrotizing enterocolitis (NEC) is a severe gastrointestinal inflammatory disease in neonates. Fucosyltransferase 2 (Fut2) regulates intestinal epithelial cell fucosylation. In this study, we aimed to investigate butyrate-mediated upregulation of Fut2 expression and the underlying mechanisms.

METHODS

In vivo and in vitro models were established. SP600125 was used to inhibit the MEK4-JNK pathway, and anisomycin was used to activate the MEK4-JNK pathway. Fut2, occludin, and ZO-1 expressions were assessed. Furthermore, intestinal permeability was analyzed by FITC-Dextran. The expression of proteins in the MEK-4-JNK pathway was examined by western blotting.

RESULTS

In vivo, the addition of exogenous butyrate notably upregulated Fut2, occludin, and ZO-1 expressions and reduced intestinal permeability in mice with NEC. Butyrate may increase the phosphorylation of MEK4, JNK, and c-jun, which are key components of the MEK4-JNK pathway. Additionally, SP600125 inhibited their phosphorylation, which was reversed by anisomycin treatment. In vitro, butyrate substantially increased occludin and ZO-1 expressions. Butyrate considerably increased Fut2 expression and markedly upregulated p-MEK4, p-JNK, and p-c-jun expressions. SP600125 administration decreased their expressions, while anisomycin administration increased their expressions.

CONCLUSION

Butyrate upregulated Fut2 expression via activation of the MEK4-JNK pathway, improved intestinal barrier integrity, and protected neonatal mice from NEC.

IMPACT

We found that exogenous butyrate could improve intestinal barrier integrity and protect against NEC in neonatal mice. Our data showed that exogenous butyrate supplementation upregulated Fut2 expression by activating the MEK4-JNK pathway. Our study provides novel insights into the pathogenesis of NEC, thereby laying an experimental foundation for future clinical research on the use of butyrate in NEC treatment.

Mechanisms and risk factors for perinatal allergic disease

Allergies are among the top causes of chronic disease in children. Their pathogenesis classically involves T helper 2 (Th2)-type inflammation driven by IgE-mediated allergen sensing. Triggers influencing allergic disease occur early in life, including before birth. The immature fetal immune system and mucosal barriers undergo periods of plasticity that are open to longitudinal programming by maternal influence. Evidence supports the importance of the maternal immune system in shaping perinatal immunity, as the transfer of cytokines, antibodies, and cells promotes offspring protection from pathogens. However, the same components may lead to allergic predisposition. Maternal-fetal interactions are further modified by epigenetic, metabolic, dietary, and microbiome-mediated effects. Here, we review how diverse maternal exposures and mediators signal across the placenta and through nursing perinatally to promote future tolerance or enhance reactivity against allergens. Improved understanding of the mechanisms predisposing for allergic disease in early life can guide the development of new therapeutics and preventative lifestyle modifications.

Maternal circadian rhythm disruption affects neonatal inflammation via metabolic reprograming of myeloid cells

Disruption of circadian rhythm during pregnancy produces adverse health outcomes in offspring; however, the role of maternal circadian rhythms in the immune system of infants and their susceptibility to inflammation remains poorly understood. Here we show that disruption of circadian rhythms in pregnant mice profoundly aggravates the severity of neonatal inflammatory disorders in both male and female offspring, such as necrotizing enterocolitis and sepsis. The diminished maternal production of docosahexaenoic acid (DHA) and the impaired immunosuppressive function of neonatal myeloid-derived suppressor cells (MDSCs) contribute to this phenomenon. Mechanistically, DHA enhances the immunosuppressive function of MDSCs via PPARγ-mediated mitochondrial oxidative phosphorylation. Transfer of MDSCs or perinatal supplementation of DHA relieves neonatal inflammation induced by maternal rhythm disruption. These observations collectively demonstrate a previously unrecognized role of maternal circadian rhythms in the control of neonatal inflammation via metabolic reprograming of myeloid cells.