Gut bacteria characteristic of the infant microbiota down-regulate inflammatory transcriptional responses in HT-29 cells

The potential immunomodulatory role of the gut microbiota in the pathogenesis of asthma: an in vitro study

The aim of this study was to investigate the influence of Bacteroides vulgatus (BV), Clostridium perfringens (CP), Parabacteroides distasonis (PD) and Ruminococcus albus (RA) lysates on secretion of selected cytokines by PBMC, MDM and HT-29 cells, as well as to determine the potential mechanisms of their action in the development of asthma. Enzyme-linked immunosorbent assays were used to analyze the effect of BV, CP, PD and RA lysates on the secretion of IL-1β, IL-6, IL-10 and TNF-α by human PBMC, MDM and HT-29 cells. BV and CP lysates significantly lowered IL-1β secretion by MDM vs. control (p < 0.05 and p < 0.001 respectively) but only at a dose of 400 µg lysate. The secretions of IL-6 by PBMC and MDM were elevated significantly above control values (p < 0.05) after administration of CP and PD lysates. BV, CP and PD lysates (100 µg) significantly increased IL-10 secretion by PBMC vs. control (p < 0.05). CP, PD and RA lysates (400 µg) significantly increased IL-10 secretion by MDM vs. control (p < 0.001). BV lysate (400 µg) also significantly increased IL-10 secretion by MDM as compared to control (p < 0.05). In PBMC and MDM, the production levels of the anti-inflammatory cytokine were increased by all the bacterial lysates used in a dose-dependent manner.

Infants exposed in utero to Hurricane Maria have gut microbiomes with reduced diversity and altered metabolic capacity

The gut microbiome is a potentially important mechanism that links prenatal disaster exposures with increased disease risks. However, whether prenatal disaster exposures are associated with alterations in the infant's gut microbiome remains unknown. We established a birth cohort study named Hurricane as the Origin of Later Alterations in Microbiome (HOLA) after Hurricane Maria struck Puerto Rico in 2017. We enrolled vaginally born Latino term infants aged 2 to 6 months, including n = 29 infants who were exposed in utero to Hurricane Maria in Puerto Rico and n = 34 infants who were conceived at least 5 months after the hurricane as controls. Shotgun metagenomic sequencing was performed on infant stool swabs. Infants exposed in utero to Hurricane Maria had a reduced diversity in their gut microbiome compared to the control infants, which was mainly seen in the exclusively formula-fed group (P = 0.02). Four bacterial species, including Bacteroides vulgatus, Clostridium innocuum, Bifidobacterium pseudocatenulatum, and Clostridium neonatale, were depleted in the exposure group compared to the control group. Compositional differences in the microbial community and metabolic genes between the exposure and control groups were significant, which were driven by the formula feeding group (P = 0.02 for the microbial community and P = 0.008 for the metabolic genes). Metabolic modules involved in carbohydrate metabolism were reduced in the exposure group. Prenatal maternal exposure to Hurricane Maria was associated with a reduced gut commensal and an altered microbial composition and metabolic potential in the offspring's gut. Breastfeeding can adjust the composition of the gut microbiomes of exposed infants. IMPORTANCE Climate change is a serious issue that is affecting human health. With more frequent and intense weather disasters due to climate change, there is an urgent need to evaluate and understand the impacts of prenatal disaster exposures on the offspring. The prenatal stage is a particularly vulnerable stage for disease origination. However, the impact of prenatal weather disaster exposures on the offspring's gut microbiome has not been evaluated. Our HOLA study starts to fill this knowledge gap and provides novel insights into the microbiome as a mechanism that links prenatal disaster exposures with elevated disease risks. Our major finding that reduced microbial diversity and altered metabolic capacity are associated with prenatal hurricane exposures warrants further studies to evaluate the impact of weather disasters on the unborn.

Effects of Human, Caprine, and Bovine Milk Fat Globules on Microbiota Adhesion and Gut Microecology

Milk fat is an essential nutrient for infant development. The effects and mechanisms of human, caprine, and bovine milk fat globules (MFGs) on the gut microbiota were investigated in this study. Human MFGs enhance the efficacy of probiotics by inhibiting pathogen function. Akkermansia and Bifidobacterium were identified as the dominant microbiota by human MFGs. Mucin and complement inhibitory proteins in human MFGs were found to inhibit different pathogens. Caprine MFGs directly promoted the colonization of probiotics and the emergence of the biomarker Allobaculum. Mucin 1 in caprine MFGs was primarily responsible for inducing probiotic adhesion. Bovine MFGs increased the abundance of Oscillospira, which reduces the risk of obesity. Due to the enrichment of cell-cell junction proteins and the lack of mucin, the regulation of gut microecology by bovine MFGs was not readily apparent. In short, this study paves the way for the development of functional infant formula.

A Comprehensive Assessment of the Safety of Blautia producta DSM 2950

In recent years, Blautia has attracted attention for its role in ameliorating host diseases. In particular, Blautia producta DSM 2950 has been considered a potential probiotic due to its ability to mitigate inflammation in poly(I:C) induced HT-29 cells. Thus, to promote the development of indigenous intestinal microorganisms with potential probiotic function, we conducted a comprehensive experimental analysis of DSM 2950 to determine its safety. This comprised a study of its potential virulence genes, antibiotic resistance genes, genomic islands, antibiotic resistance, and hemolytic activity and a 14-day test of its acute oral toxicity in mice. The results indicated no toxin-related virulence genes in the DSM 2950 genome. Most of the genomic islands in DSM 2950 were related to metabolism, rather than virulence expression. DSM 2950 was sensitive to most of the tested antibiotics but was tolerant of treatment with kanamycin, neomycin, clindamycin, or ciprofloxacin, probably because it possessed the corresponding antibiotic resistance genes. Oral acute toxicity tests indicated that the consumption of DSM 2950 does not cause toxic side effects in mice. Overall, the safety profile of DSM 2950 confirmed that it could be a candidate probiotic for use in food and pharmaceutical preparations.

Community Metabolic Interactions, Vitamin Production and Prebiotic Potential of Medicinal Herbs Used for Immunomodulation

Historically, the health benefits and immunomodulatory potential of medicinal herbs have been considered an intrinsic quality of the herb itself. We have hypothesized that the health benefits of medicinal herbs may be partially due to their prebiotic potential that alter gut microbiota leading to changes in short chain fatty acids and vitamin production or biotransformation of herb encoded molecules and secondary metabolites. Accumulating studies emphasize the relationship between the gut microbiota and host immune function. While largely unknown, these interactions are mediated by secreted microbial products that activate or repress a variety of immune cell types. Here we evaluated the effect of immunomodulatory, medicinal Ayurvedic herbs on gut microbiota in vitro using 16S rRNA sequencing to assess changes in community composition and functional potential. All immunomodulatory herbs displayed substantial prebiotic potential, targeting unique taxonomic groups. Application of genome reconstruction and analysis of biosynthetic capacity of herb selected communities suggests that many of the 11 herbs tested altered the community metabolism as the result of differential glycan harvest and sugar utilization and secreted products including multiple vitamins, butyrate, and propionate that may impact host physiology and immune function. Taken together, these results provide a useful framework for the further evaluation of these immunomodulatory herbs in vivo to maintain immune homeostasis or achieve desired regulation of immune components in the context of disease.