Probiotics modulate the gut microbiota, which in turn regulate immune responses to maintain balanced immune homeostasis in the host. However, it is unclear how probiotic bacteria regulate immune responses. In this study we investigated the immunomodulatory effects of heat-killed probiotics, including Lactiplantibacillus plantarum KC3 (LP3), Lactiplantibacillus plantarum CKDB008 (LP8), and Limosilactobacillus fermentum SRK414 (LF4), via phagocytosis, nitric oxide (NO), and pro-inflammatory cytokine production in macrophages. We thus found that heat-killed LP8 could promote the clearance of foreign pathogens by enhancing the phagocytosis of macrophages. Treatment with heat-killed LP8 induced the production of NO and pro-inflammatory cytokines, including TNF-α, IL-6, and IL-1β. In addition, heat-killed LP8 suppressed the production of NO and cytokines in LPS-induced RAW264.7 cells, suggesting that heat-killed LP8 exerts immunomodulatory effects depending on the host condition. In sum, these results indicate that heat-killed LP8 possesses the potential for immune modulation while providing a molecular basis for the development of functional probiotics prepared from inactivated bacterial cells.
Probiotics are defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host" (FAO/WHO 2002). While probiotics have several known benefits, there have been safety issues related to their use in humans and animals. In 2002, the Food and Agriculture Organization/World Health Organization (FAO/WHO) reported that probiotics may cause side-effect such as systemic infection, deleterious metabolism, and excessive immune response in susceptible subjects or exhibit harmful gene transfer (FAO/WHO 2002). Furthermore, the European Food Safety Authority (EFSA) announced safety assessment guidance for probiotics by focusing on antimicrobial resistance (AMR) [1] and made it mandatory to examine susceptibility of all bacterial strains used as feed additives to the most relevant antibiotics. As a basic requirement, the minimum inhibitory concentration (MIC) should be determined for nine antibiotics (ampicillin, vancomycin, tetracycline, and others). The resistance of a bacterial strain to any specific antibiotic higher than the microbiological cut-off values defined by EFSA is deemed indicative of the presence of acquired resistance. Further, additional information is needed on the genetic basis of the AMR. For the genetic safety evaluation of microorganisms, EFSA recently recommended the taxonomic identification and characterization of their potential functional traits of concern, which may include virulence factors (VFs) and AMR [2,3].Lactobacillus plantarum, one of the lactic acid bacteria (LAB) widely used worldwide as a probiotic [4-7], was differently classified from genetically related Lactobacillus species on the basis of whole genome sequencing data and newly denominated as Lactiplantibacillus (Lp.) plantarum [8]. Many researchers have reported the safety of Lp. plantarum using molecular biological approaches, microbiological tools, and bioinformatics analyses [9-13]. However, the safety of Lp. plantarum strains cannot be guaranteed without verification, as some Lactobacillus strains have been reported to exhibit AMR and may not meet the EFSA guideline criteria. The most representative case was the intrinsic resistance of Lp. plantarum to vancomycin [14-16], caused by cell wall composition and structural changes [17]. Intrinsic resistance to antibiotics (sometimes termed as natural resistance) [1], inherent to a bacterial species, is considered relatively safe. In contrast to intrinsic resistance, non-intrinsic resistance to other antibiotics has been reported for other . The most important aspect while dealing with AMR is non-intrinsic and acquired resistance, which can be transferred to other bacteria byThe safety of the probiotic strain Q180, which exerts postprandial lipid-lowering effects, was bioinformatically and phenotypically evaluated. The genome of strain Q180 was completely sequenced, and single circular chromosome of 3,197,263 bp without any plasmid was generated. Phylogenetic and related analyses using16S rRNA gene and whole-genome sequences revealed that s...
Probiotics have been shown to possess anti-inflammatory effects in the gut by directly reducing the production of pro-inflammatory cytokines and by secreting anti-inflammatory molecules. However, their systemic anti-inflammatory effects have not been thoroughly investigated. In this study, we aimed to develop probiotics that have efficacy in both intestinal and lung inflammation. Lactobacillus plantarum KC3 (KC3), which was isolated from kimchi, was selected as a pre-candidate based on its inhibitory effects on the production of pro-inflammatory cytokines in vitro. To further validate the effectiveness of KC3, we used ear edema, DSS-induced colitis, and ambient particulate-matter-induced lung inflammation models. First, KC3 exhibited direct anti-inflammatory effects on intestinal cells with the inhibition of IL-1β and TNF-α production. Additionally, KC3 treatment alleviated ear edema and DSS-induced colic inflammation, improving colon length and increasing the number of regulatory T cells. Beyond its local intestinal anti-inflammatory activity, KC3 inhibited pro-inflammatory cytokines in the bronchoalveolar fluid and prevented neutrophil infiltration in the lungs. These results suggest that KC3 could be a potential functional ingredient with respiratory protective effects against air-pollutant-derived inflammation, as well as for the treatment of local gut disorders.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.