In vitro Digestion: Exploring the probiotic abilities and metabolization of human milk oligosaccharides by two strains of Limosilactobacillus fermentum isolated from breast milk

Human breast milk (HBM) serves as the most optimal nourishment for infants, not only providing essential nutrition but also boasting a rich array of immune components. These include secretory antibodies, immune cells, antimicrobial proteins (like lactoferrin and lysozyme), cytokines, and human milk oligosaccharides. Today, the presence of a specific microbiome in human milk is known. Our primary research involves the examination of certain probiotic properties displayed by two strains of Limosilactobacillus fermentum, which were isolated from breast milk. Furthermore, our goal was to evaluate their ability to metabolize breast milk-derived oligosaccharides through an in vitro digestion simulation system. The in vitro model simulating gastrointestinal digestion was performed according to INFOGEST method with some modification. We used various molecular techniques to isolate and identify strains from breast milk. Additionally, we employed different biochemical analyses to determine specific enzyme activities, and we also assessed the fundamental probiotic characteristics of two strains Limosilactobacillus fermentum. We found good probiotic characteristics in the examined strains, as well as favorable growth properties in the presence of specific human milk oligosaccharides. In this regard, we believe that breast milk represents a rich source for isolating potential probiotic strains

Metabolic profiling of probiotic strain Lactobacillus delbrueckii subsp. bulgaricus L14 cultivated in presence of prebiotic oligosaccharides and polysaccharides in simulating in vitro gastrointestinal tract system

AbstractThis study examined the effect of lactulose, galactooligosaccharide, fructooligosaccharide, inulin, and β-glucan on the probiotic strain Lactobacillus delbrueckii subsp. bulgaricus L14, cultivated in an in vitro gastrointestinal system model. We analyzed the degree of hydrolysis of the studied prebiotic oligosaccharides in condition of simulated gastric fluid. The results showed that lactulose had the highest resistance, galactooligosaccharide underwent hydrolysis, and fructooligosaccharide was the most sensitive. Among the polysaccharides, fructose was released from inulin and glucose from β-glucan. Short-chain oligosaccharides and metabolites derived from studied prebiotic oligosaccharides and polysaccharides, supported the growth of probiotic strain L14, which showed the highest growth with fructooligosaccharides and β-glucan as carbohydrate sources. The profile of the activated enzymes secreted by the probiotic strain L14, indicated their inducible character. Beta-galactosidase was activated in the presence of lactulose and GalOS, inulinase was activated in the presence of inulin and fructooligosaccharides, and β-glucosidase was activated in the presence of β-glucan fragments. Analysis of the produced organic and short-chain fatty acids showed that the typical representative of the homofermentative lactobacilli Lb. delbrueckii subsp. bulgaricus L14 changes its metabolism from a homofermentative to a heterofermentative type, best expressed in the presence of lactulose, galactooligosaccharide, and β-glucan

miR-31a-5p promotes postnatal cardiomyocyte proliferation by targeting RhoBTB1

A limited number of microRNAs (miRNAs, miRs) have been reported to control postnatal cardiomyocyte proliferation, but their strong regulatory effects suggest a possible therapeutic approach to stimulate regenerative capacity in the diseased myocardium. This study aimed to investigate the miRNAs responsible for postnatal cardiomyocyte proliferation and their downstream targets. Here, we compared miRNA profiles in cardiomyocytes between postnatal day 0 (P0) and day 10 (P10) using miRNA arrays, and found that 21 miRNAs were upregulated at P10, whereas 11 were downregulated. Among them, miR-31a-5p was identified as being able to promote cardiomyocyte proliferation as determined by proliferating cell nuclear antigen (PCNA) expression, double immunofluorescent labeling for α-actinin and 5-ethynyl-2-deoxyuridine (EdU) or Ki-67, and cell number counting, whereas miR-31a-5p inhibition could reduce their levels. RhoBTB1 was identified as a target gene of miR-31a-5p, mediating the regulatory effect of miR-31a-5p in cardiomyocyte proliferation. Importantly, neonatal rats injected with a miR-31a-5p antagomir at day 0 for three consecutive days exhibited reduced expression of markers of cardiomyocyte proliferation including PCNA expression and double immunofluorescent labeling for α-actinin and EdU, Ki-67 or phospho-histone-H3. In conclusion, miR-31a-5p controls postnatal cardiomyocyte proliferation by targeting RhoBTB1, and increasing miR-31a-5p level might be a novel therapeutic strategy for enhancing cardiac reparative processes