The emerging role of group 3 innate lymphoid cells in the neonate: interaction with the maternal and neonatal microbiome

Triggers for the onset and recurrence of psoriasis: a review and update

Psoriasis is an immune-mediated inflammatory skin disease, involving a complex interplay between genetic and environmental factors. Previous studies have demonstrated that genetic factors play a major role in the pathogenesis of psoriasis. However, non-genetic factors are also necessary to trigger the onset and recurrence of psoriasis in genetically predisposed individuals, which include infections, microbiota dysbiosis of the skin and gut, dysregulated lipid metabolism, dysregulated sex hormones, and mental illness. Psoriasis can also be induced by other environmental triggers, such as skin trauma, unhealthy lifestyles, and medications. Understanding how these triggers play a role in the onset and recurrence of psoriasis provides insights into psoriasis pathogenesis, as well as better clinical administration. In this review, we summarize the triggers for the onset and recurrence of psoriasis and update the current evidence on the underlying mechanism of how these factors elicit the disease. Video Abstract.

Natural killer cells and innate lymphoid cells but not NKT cells are mature in their cytokine production at birth

Early life is a time of increased susceptibility to infectious diseases and development of allergy. Innate lymphocytes are crucial components of the initiation and regulation of immune responses at mucosal surfaces, but functional differences in innate lymphocytes early in life are not fully described. We aimed to characterize the abundance and function of different innate lymphocyte cell populations in cord blood in comparison to that of adults. Blood was collected from adult donors and umbilical vessels at birth. Multicolor flow cytometry panels were used to identify and characterize lymphocyte populations and their capacity to produce hallmark cytokines. Lymphocytes were more abundant in cord blood compared to adults, however, mucosal-associated invariant T cells and natural killer T (NKT)-like cells, were far less abundant. The capacity of NKT-like cells to produce cytokines and their expression of the cytotoxic granule protein granzyme B and the marker of terminal differentiation CD57 were much lower in cord blood than in adults. In contrast, natural killer (NK) cells were as abundant in cord blood as in adults, they could produce IFNγ, and their expression of granzyme B was not significantly different from that of adult NK cells, although CD57 expression was lower. All innate lymphoid cell (ILC) subsets were more abundant in cord blood, and ILC1 and ILC2 were capable of production of IFNγ and IL-13, respectively. In conclusion, different innate lymphoid cells differ in both abundance and function in peripheral blood at birth and with important implications for immunity in early life.

Maternal polysorbate 80 exposure causes intestinal ILCs and CD4+ T cell developmental abnormalities in mouse offspring

This study aimed to investigate the transgenerational impacts of maternal intake of polysorbate 80 (P80), an emulsifier widely used in modern society, on the development of offspring immunity. Our results revealed that maternal P80 treatment led to impaired differentiation of innate lymphoid cells (ILCs) and CD4+ T cells in the small intestinal lamina propria (SiLP), resulting in intestinal dyshomeostasis in female offspring. Furthermore, we found that SiLP ILCs abundances were significantly altered in 0-day-old fetuses from P80-treated mothers, indicating a prenatal impact of P80-treated mothers on offspring immunity. Additionally, cesarean section and foster-nursing studies demonstrated that P80-induced altered SiLP ILCs in 0-day-old fetuses could further induce dysregulation of ILCs and CD4+ T cells in the SiLP, thus promoting intestinal dysregulation in offspring later in life. Overall, our findings suggest that maternal P80 intake could prenatally program the development of offspring immunity, exerting a significant and long-lasting impact.

Neonatal development of intestinal neuroimmune interactions

Interactions between the enteric nervous system (ENS), immune system, and gut microbiota regulate intestinal homeostasis in adults, but their development and role(s) in early life are relatively underexplored. In early life, these interactions are dynamic, because the mucosal immune system, microbiota, and the ENS are developing and influencing each other. Moreover, disrupting gut microbiota and gut immune system development, and potentially ENS development, by early-life antibiotic exposure increases the risk of diseases affecting the gut. Here, we review the development of the ENS and immune/epithelial cells, and identify potential critical periods for their interactions and development. We also highlight knowledge gaps that, when addressed, may help promote intestinal homeostasis, including in the settings of early-life antibiotic exposure.

Murine in utero exposure to simulated complex urban air pollution disturbs offspring gut maturation and microbiota during intestinal suckling-to-weaning transition in a sex-dependent manner

Background

Emerging data indicate that prenatal exposure to air pollution may lead to higher susceptibility to several non-communicable diseases. Limited research has been conducted due to difficulties in modelling realistic air pollution exposure. In this study, pregnant mice were exposed from gestational day 10–17 to an atmosphere representative of a 2017 pollution event in Beijing, China. Intestinal homeostasis and microbiota were assessed in both male and female offspring during the suckling-to-weaning transition.

Results

Sex-specific differences were observed in progeny of gestationally-exposed mice. In utero exposed males exhibited decreased villus and crypt length, vacuolation abnormalities, and lower levels of tight junction protein ZO-1 in ileum. They showed an upregulation of absorptive cell markers and a downregulation of neonatal markers in colon. Cecum of in utero exposed male mice also presented a deeply unbalanced inflammatory pattern. By contrast, in utero exposed female mice displayed less severe intestinal alterations, but included dysregulated expression of Lgr5 in colon, Tjp1 in cecum, and Epcam, Car2 and Sis in ileum. Moreover, exposed female mice showed dysbiosis characterized by a decreased weighted UniFrac β-diversity index, a higher abundance of Bacteroidales and Coriobacteriales orders, and a reduced Firmicutes/Bacteroidetes ratio.

Conclusion

Prenatal realistic modelling of an urban air pollution event induced sex-specific precocious alterations of structural and immune intestinal development in mice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00481-y.

Look Who's Talking: Host and Pathogen Drivers of Staphylococcus epidermidis Virulence in Neonatal Sepsis

Preterm infants are at increased risk for invasive neonatal bacterial infections. S. epidermidis, a ubiquitous skin commensal, is a major cause of late-onset neonatal sepsis, particularly in high-resource settings. The vulnerability of preterm infants to serious bacterial infections is commonly attributed to their distinct and developing immune system. While developmentally immature immune defences play a large role in facilitating bacterial invasion, this fails to explain why only a subset of infants develop infections with low-virulence organisms when exposed to similar risk factors in the neonatal ICU. Experimental research has explored potential virulence mechanisms contributing to the pathogenic shift of commensal S. epidermidis strains. Furthermore, comparative genomics studies have yielded insights into the emergence and spread of nosocomial S. epidermidis strains, and their genetic and functional characteristics implicated in invasive disease in neonates. These studies have highlighted the multifactorial nature of S. epidermidis traits relating to pathogenicity and commensalism. In this review, we discuss the known host and pathogen drivers of S. epidermidis virulence in neonatal sepsis and provide future perspectives to close the gap in our understanding of S. epidermidis as a cause of neonatal morbidity and mortality.