Lactobacillus gasseri LA39 Activates the Oxidative Phosphorylation Pathway in Porcine Intestinal Epithelial Cells

Lycopene alleviates Deoxynivalenol-induced toxicity in Porcine intestinal epithelial cells by mediating mitochondrial function

Deoxynivalenol (DON) is widely found in food and feed, posing a threat to human and animal health. Lycopene (Lyc) is a natural plant extracts with significant antioxidant properties. This study was conducted to investigate the protective effects of Lyc on IPEC-J2 cells upon DON exposure. The detection of cell viability and trypan blue staining showed that Lyc alleviated cell damage and decreased cell apoptotic rate induced by DON. The analysis of reactive oxygen species (ROS) level and antioxidant parameter measurements showed that Lyc significantly down-regulated the content of ROS and restored antioxidant enzyme activity. Furthermore, mitochondrial membrane potential (ΔΨm) detection, mitochondrial DNA copy number (mtDNAcn) assay and adenosine triphosphate (ATP) concentration detection showed Lyc improved mitochondrial function after DON exposure. The results of transcriptome analysis, ROS detection and CCK8 assay suggested that Lyc may activated the oxidative phosphorylation (OXPHOS) to improve mitochondrial function. Conclusively, our results suggested that Lyc alleviated DON-induced oxidative stress by improving mitochondrial function through OXPHOS signaling pathway.

Intestinal microbiota imbalance resulted by anti-Toxoplasma gondii immune responses aggravate gut and brain injury

BACKGROUND

Toxoplasma gondii infection affects a significant portion of the global population, leading to severe toxoplasmosis and, in immunocompromised patients, even death. During T. gondii infection, disruption of gut microbiota further exacerbates the damage to intestinal and brain barriers. Therefore, identifying imbalanced probiotics during infection and restoring their equilibrium can regulate the balance of gut microbiota metabolites, thereby alleviating tissue damage.

METHODS

Vimentin gene knockout (vim-/-) mice were employed as an immunocompromised model to evaluate the influence of host immune responses on gut microbiota balance during T. gondii infection. Behavioral experiments were performed to assess changes in cognitive levels and depressive tendencies between chronically infected vim-/- and wild-type (WT) mice. Fecal samples were subjected to 16S ribosomal RNA (rRNA) sequencing, and serum metabolites were analyzed to identify potential gut probiotics and their metabolites for the treatment of T. gondii infection.

RESULTS

Compared to the immunocompetent WT sv129 mice, the immunocompromised mice exhibited lower levels of neuronal apoptosis and fewer neurobehavioral abnormalities during chronic infection. 16S rRNA sequencing revealed a significant decrease in the abundance of probiotics, including several species of Lactobacillus, in WT mice. Restoring this balance through the administration of Lactobacillus murinus and Lactobacillus gasseri significantly suppressed the T. gondii burden in the intestine, liver, and brain. Moreover, transplantation of these two Lactobacillus spp. significantly improved intestinal barrier damage and alleviated inflammation and neuronal apoptosis in the central nervous system. Metabolite detection studies revealed that the levels of various Lactobacillus-related metabolites, including indole-3-lactic acid (ILA) in serum, decreased significantly after T. gondii infection. We confirmed that L. gasseri secreted much more ILA than L. murinus. Notably, ILA can activate the aromatic hydrocarbon receptor signaling pathway in intestinal epithelial cells, promoting the activation of CD8+ T cells and the secretion of interferon-gamma.

CONCLUSION

Our study revealed that host immune responses against T. gondii infection severely disrupted the balance of gut microbiota, resulting in intestinal and brain damage. Lactobacillus spp. play a crucial role in immune regulation, and the metabolite ILA is a promising therapeutic compound for efficient and safe treatment of T. gondii infection.

Development of small intestinal barrier function and underlying mechanism in Chinese indigenous and Duroc piglets during suckling and weaning periods

This study explored the developmental changes in small intestinal barrier function and the potential regulatory roles of intestinal microbiota and metabolites in different breeds of piglets during suckling and weaning periods. Taoyuan black (TB), Xiangcun black (XB), and Duroc (DR) piglets (10 litters per breed; half male and half female) were selected for sampling to evaluate the intestinal barrier-related indexes and intestinal microbiota and metabolites at 1, 10, 21 (weaned), and 24 (3 d after weaning) d old. The results showed that weaning led to severe shedding of small intestinal microvilli and sparse microvilli arrangement. D-lactate level in the ileum of TB and XB piglets during suckling and weaning periods was lower (P < 0.01) than that of DR piglets, as well as the ileal diamine oxidase level at 1 d old. The expression level of mucin 1 was higher (P < 0.05) in the ileum of TB and XB piglets than that of DR piglets, and it was the highest in the ileum of TB piglets at 21 d old. The expression levels of mucin 2 and mucin 13 were higher (P < 0.10) in TB and XB piglets than those of DR piglets at 21 d old, whereas mucin 2 and mucin 13 in the ileum of TB and XB piglets were higher (P < 0.05) than those of DR piglets at 24 d old. TB and XB piglets had a lower relative abundance of Escherichia_Shigella at 21 and 24 d old, but they had higher Streptococcus at 1 and 24 d old than DR piglets (P < 0.01). Differential metabolites between the three breeds of piglets were mainly related to oxidative phosphorylation, steroid biosynthesis, and bile acid synthesis. Collectively, these findings suggest that different pig breeds present differences in the development of the small intestinal barrier function. Compared with DR piglets, TB and XB piglets had higher intestinal permeability during the suckling period and a stronger intestinal mechanical barrier after weaning. Moreover, intestinal microbiota and metabolites are the key factors for developing small intestinal barrier functions in different breeds of piglets.

Importance of microbial amphiphiles: interaction potential of biosurfactants, amyloids, and other exo-polymeric-substances

Microorganisms produce a diverse group of biomolecules having amphipathic nature (amphiphiles). Microbial amphiphiles, including amyloids, bio-surfactants, and other exo-polymeric substances, play a crucial role in various biological processes and have gained significant attention recently. Although diverse in biochemical composition, these amphiphiles have been reported for common microbial traits like biofilm formation and pathogenicity due to their ability to act as surface active agents with active interfacial properties essential for microbes to grow in various niches. This enables microbes to reduce surface tension, emulsification, dispersion, and attachment at the interface. In this report, the ecological importance and biotechnological usage of important amphiphiles have been discussed. The low molecular weight amphiphiles like biosurfactants, siderophores, and peptides showing helical and antimicrobial activities have been extensively reported for their ability to work as quorum-sensing mediators. While high molecular weight amphiphiles make up amyloid fibers, exopolysaccharides, liposomes, or magnetosomes have been shown to have a significant influence in deciding microbial physiology and survival. In this report, we have discussed the functional similarities and biochemical variations of several amphipathic biomolecules produced by microbes, and the present report shows these amphiphiles showing polyphyletic and ecophysiological groups of microorganisms and hence can `be replaced in biotechnological applications depending on the compatibility of the processes.

Lactobacillus gasseri LA39 promotes hepatic primary bile acid biosynthesis and intestinal secondary bile acid biotransformation

A growing body of evidence has linked the gut microbiota to liver metabolism. The manipulation of intestinal microflora has been considered as a promising avenue to promote liver health. However, the effects of Lactobacillus gasseri LA39, a potential probiotic, on liver metabolism remain unclear. Accumulating studies have investigated the proteomic profile for mining the host biological events affected by microbes, and used the germ-free (GF) mouse model to evaluate host-microbe interaction. Here, we explored the effects of L. gasseri LA39 gavage on the protein expression profiles of the liver of GF mice. Our results showed that a total of 128 proteins were upregulated, whereas a total of 123 proteins were downregulated by treatment with L. gasseri LA39. Further bioinformatics analyses suggested that the primary bile acid (BA) biosynthesis pathway in the liver was activated by L. gasseri LA39. Three differentially expressed proteins (cytochrome P450 family 27 subfamily A member 1 (CYP27A1), cytochrome P450 family 7 subfamily B member 1 (CYP7B1), and cytochrome P450 family 8 subfamily B member 1 (CYP8B1)) involved in the primary BA biosynthesis pathway were further validated by western blot assay. In addition, targeted metabolomic analyses demonstrated that serum and fecal β‍-muricholic acid (a primary BA), dehydrolithocholic acid (a secondary BA), and glycolithocholic acid-3-sulfate (a secondary BA) were significantly increased by L. gasseri LA39. Thus, our data revealed that L. gasseri LA39 activates the hepatic primary BA biosynthesis and promotes the intestinal secondary BA biotransformation. Based on these findings, we suggest that L. gasseri LA39 confers an important function in the gut‒liver axis through regulating BA metabolism.

Core-predominant gut fungus Kazachstania slooffiae promotes intestinal epithelial glycolysis via lysine desuccinylation in pigs

BACKGROUND

Gut fungi are increasingly recognized as important contributors to host physiology, although most studies have focused on gut bacteria. Post-translational modifications (PTMs) of proteins play vital roles in cell metabolism. However, the contribution of gut fungi to host protein PTMs remains unclear. Mining gut fungi that mediate host protein PTMs and dissecting their mechanism are urgently needed.

RESULTS

We studied the gut fungal communities of 56 weaned piglets and 56 finishing pigs from seven pig breeds using internal transcribed spacer (ITS) gene amplicon sequencing and metagenomics. The results showed that Kazachstania slooffiae was the most abundant gut fungal species in the seven breeds of weaned piglets. K. slooffiae decreased intestinal epithelial lysine succinylation levels, and these proteins were especially enriched in the glycolysis pathway. We demonstrated that K. slooffiae promoted intestinal epithelial glycolysis by decreasing lysine succinylation by activating sirtuin 5 (SIRT5). Furthermore, K. slooffiae-derived 5'-methylthioadenosine metabolite promoted the SIRT5 activity.

CONCLUSIONS

These findings provide a landscape of gut fungal communities of pigs and suggest that K. slooffiae plays a crucial role in intestinal glycolysis metabolism through lysine desuccinylation. Our data also suggest a potential protective strategy for pigs with an insufficient intestinal energy supply. Video Abstract.

Markers of immune dysregulation in response to the ageing gut: insights from aged murine gut microbiota transplants

BACKGROUND

Perturbations in the composition and diversity of the gut microbiota are accompanied by a decline in immune homeostasis during ageing, characterized by chronic low-grade inflammation and enhanced innate immunity. Genetic insights into the interaction between age-related alterations in the gut microbiota and immune function remain largely unexplored.

METHODS

We investigated publicly available transcriptomic gut profiles of young germ-free mouse hosts transplanted with old donor gut microbiota to identify immune-associated differentially expressed genes (DEGs). Literature screening of the Gene Expression Omnibus and PubMed identified one murine (Mus musculus) gene expression dataset (GSE130026) that included small intestine tissues from young (5-6 weeks old) germ-free mice hosts that were compared following 8 weeks after transplantation with either old (~ 24-month old; n = 5) or young (5-6 weeks old; n = 4) mouse donor gut microbiota.

RESULTS

A total of 112 differentially expressed genes (DEGs) were identified and used to construct a gut network of encoded proteins, in which DEGs were functionally annotated as being involved in an immune process based on gene ontology. The association between the expression of immune-process DEGs and abundance of immune infiltrates from gene signatures in normal colorectal tissues was estimated from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) project. The analysis revealed a 25-gene signature of immune-associated DEGs and their expression profile was positively correlated with naïve T-cell, effector memory T-cell, central memory T-cell, resident memory T-cell, exhausted T-cell, resting Treg T-cell, effector Treg T-cell and Th1-like colorectal gene signatures. Conclusions These genes may have a potential role as candidate markers of immune dysregulation during gut microbiota ageing. Moreover, these DEGs may provide insights into the altered immune response to microbiota in the ageing gut, including reduced antigen presentation and alterations in cytokine and chemokine production.

The Growth Medium Affects the Viability of IPEC-J2 Animal Cell Line in the Presence of Probiotic Bacteria

Background: The IPEC-J2 cell line is frequently used as an in vitro model to study the bioactivity of live probiotics. However, lactic acid bacteria (LB) acidify the medium, and the impact of pH and lactic acid accumulation on cell viability seem to be underestimated. Methods: IPEC-J2 viability was assessed by neutral red and flow cytometry in the presence of eight probiotics at concentrations between 106 and 109 bacteria/mL in maintenance and buffered media. Results: It was shown that a high inoculation level led to higher cytotoxic effects on IPEC-J2 cells after 22 h of incubation and that viability losses were more related to a combination of low pH and lactic acid than to the probiotics themselves. Furthermore, with LB at 106 and 107 bacteria/mL, the addition of phosphates to the media significantly reduced the drop in the pH and preserved the IPEC-J2 viability between 100% and 69%, compared to a highly variable viability between 100% and 17.5% in the unbuffered media. Conclusions: Under certain in vitro conditions, probiotics can lead to the deterioration of animal cells, and pH neutralization is an essential parameter in the cell–probiotic system in order to preserve cell viability and to better evaluate the bioactive properties of live probiotics.

Proteomics-based evaluation of the mechanism underlying vascular injury via DNA interstrand crosslinks, glutathione perturbation, mitogen-activated protein kinase, and Wnt and ErbB signaling pathways induced by crotonaldehyde

Crotonaldehyde (CRA)—one of the major environmental pollutants from tobacco smoke and industrial pollution—is associated with vascular injury (VI). We used proteomics to systematically characterize the presently unclear molecular mechanism of VI and to identify new related targets or signaling pathways after exposure to CRA. Cell survival assays were used to assess DNA damage, whereas oxidative stress was determined using colorimetric assays and by quantitative fluorescence study; additionally, cyclooxygenase-2, mitogen-activated protein kinase pathways, Wnt3a, β-catenin, phospho-ErbB2, and phospho-ErbB4 were assessed using ELISA. Proteins were quantitated via tandem mass tag-based liquid chromatography-mass spectrometry and bioinformatics analyses, and 34 differentially expressed proteins were confirmed using parallel reaction monitoring, which were defined as new indicators related to the mechanism underlying DNA damage; glutathione perturbation; mitogen-activated protein kinase; and the Wnt and ErbB signaling pathways in VI based on Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and protein–protein interaction network analyses. Parallel reaction monitoring confirmed significant (p < 0.05) upregulation (> 1.5-fold change) of 23 proteins and downregulation (< 0.667-fold change) of 11. The mechanisms of DNA interstrand crosslinks; glutathione perturbation; mitogen-activated protein kinase; cyclooxygenase-2; and the Wnt and ErbB signaling pathways may contribute to VI through their roles in DNA damage, oxidative stress, inflammation, vascular dysfunction, endothelial dysfunction, vascular remodeling, coagulation cascade, and the newly determined signaling pathways. Moreover, the Wnt and ErbB signaling pathways were identified as new disease pathways involved in VI. Taken together, the elucidated underlying mechanisms may help broaden existing understanding of the molecular mechanisms of VI induced by CRA.

Gut health: The results of microbial and mucosal immune interactions in pigs

There are a large number of microorganisms in the porcine intestinal tract. These microorganisms and their metabolites contribute to intestinal mucosal immunity, which is of great importance to the health of the host. The host immune system can regulate the distribution and composition of intestinal microorganisms and regulate the homeostasis of intestinal flora by secreting a variety of immune effector factors, such as mucin, secretory immunoglobulin A (sIgA), regenerating islet-derived III (RegIII)γ, and defensin. Conversely, intestinal microorganisms can also promote the differentiation of immune cells including regulatory T cells (T_reg) and Th17 cells through their specific components or metabolites. Studies have shown that imbalances in the intestinal flora can lead to bacterial translocation and compromised intestinal barrier function, affecting the health of the body. This review focuses on the composition of the pig intestinal flora and the characteristics of intestinal mucosal immunity, discusses the interaction mechanism between the flora and intestinal mucosal immunity, as well as the regulation through fecal microbiota transplantation (FMT), dietary nutritional composition, probiotics and prebiotics of pig intestinal microecology. Finally, this review provides insights into the relationship between intestinal microorganisms and the mucosal immune system.

Ammonium monoethyloxalate (AmEtOx): a new agent for the conservation of carbonate stone substrates

Ammonium monoethyloxalate (AmEtOx) is proposed as a consolidanting agent for carbonate stones such as biomicritic limestone and marble, resulting in the formation of a microcrystalline passivating phase of calcium oxalate (whewellite and weddellite).

Lactobacillus frumenti mediates energy production via fatty acid β-oxidation in the liver of early-weaned piglets

Background

Early-weaning of piglets is often accompanied by severe disorders, especially diarrhea. The gut microbiota and its metabolites play a critical role in the maintenance of the physiologic and metabolic homeostasis of the host. Our previous studies have demonstrated that oral administration of Lactobacillus frumenti improves epithelial barrier functions and confers diarrhea resistance in early-weaned piglets. However, the metabolic response to L. frumenti administration remains unclear. Then, we conducted simultaneous serum and hepatic metabolomic analyses in early-weaned piglets administered by L. frumenti or phosphate-buffered saline (PBS).

Results

A total of 100 6-day-old crossbred piglets (Landrace × Yorkshire) were randomly divided into two groups and piglets received PBS (sterile, 2 mL) or L. frumenti (suspension in PBS, 10⁸ CFU/mL, 2 mL) by oral administration once per day from 6 to 20 days of age. Piglets were weaned at 21 days of age. Serum and liver samples for metabolomic analyses were collected at 26 days of age. Principal components analysis (PCA) showed that L. frumenti altered metabolism in serum and liver. Numerous correlations (P < 0.05) were identified among the serum and liver metabolites that were affected by L. frumenti. Concentrations of guanosine monophosphate (GMP), inosine monophosphate (IMP), and uric acid were higher in serum of L. frumenti administration piglets. Pathway analysis indicated that L. frumenti regulated fatty acid and amino acid metabolism in serum and liver. Concentrations of fatty acid β-oxidation related metabolites in serum (such as 3-hydroxybutyrylcarnitine, C4-OH) and liver (such as acetylcarnitine) were increased after L. frumenti administration.

Conclusions

Our findings suggest that L. frumenti regulates lipid metabolism and amino acid metabolism in the liver of early-weaned piglets, where it promotes fatty acid β-oxidation and energy production. High serum concentrations of nucleotide intermediates, which may be an alternative strategy to reduce the incidence of diarrhea in early-weaned piglets, were further detected. These findings broaden our understanding of the relationships between the gut microbiota and nutrient metabolism in the early-weaned piglets.

Lactobacillus frumenti improves antioxidant capacity via nitric oxide synthase 1 in intestinal epithelial cells

Oxidative damages have adverse effects on mammals. Growing studies have focused on exploring new antioxidants. Here, we report that Lactobacillus frumenti increases the total antioxidation capacity activities and decreases the total reactive oxygen species levels in porcine intestinal epithelial cells. Comparative proteomics revealed that expressions of peroxiredoxin 2, isocitrate dehydrogenase 1, NAD(P)H dehydrogenase quinone 1, antioxidant protein 1, and metallothionein-2A, which are associated with antioxidant defense system, were significantly increased with L. frumenti treatment. In germ-free mice, L. frumenti treatment also remarkably improves the intestinal antioxidant capacity. We further illustrated that nitric oxide production-mediated by nitric oxide synthase 1 activation is essential for L. frumenti-induced improvements in intestinal epithelial antioxidant capacity and barrier function. This study suggested that L. frumenti may be a potential probiotic used to prevent oxidative stress-induced aging and diseases in mammals.-Nie, Y., Hu, J., Hou, Q., Zheng, W., Zhang, X., Yang, T., Ma, L., Yan, X. Lactobacillus frumenti improves antioxidant capacity via nitric oxide synthase 1 in intestinal epithelial cells.