Development of a blocker of the universal phosphatidylserine- and phosphatidylethanolamine-dependent viral entry pathways

Envelope phosphatidylserine (PtdSer) and phosphatidylethanolamine (PtdEtr) have been shown to mediate binding of enveloped viruses. However, commonly used PtdSer binding molecules such as Annexin V cannot block PtdSer-mediated viral infection. Lack of reagents that can conceal envelope PtdSer and PtdEtr and subsequently inhibit infection hinders elucidation of the roles of the envelope phospholipids in viral infection. Here, we developed sTIM1dMLDR801, a reagent capable of blocking PtdSer- and PtdEtr-dependent infection of enveloped viruses. Using sTIM1dMLDR801, we found that envelope PtdSer and/or PtdEtr can support ZIKV infection of not only human but also mosquito cells. In a mouse model for ZIKV infection, sTIM1dMLDR801 reduced ZIKV load in serum and the spleen, indicating envelope PtdSer and/or PtdEtr support in viral infection in vivo. sTIM1dMLDR801 will enable elucidation of the roles of envelope PtdSer and PtdEtr in infection of various virus species, thereby facilitating identification of their receptors and transmission mechanisms.

Gut complement induced by the microbiota combats pathogens and spares commensals

Canonically, the complement system is known for its rapid response to remove microbes in the bloodstream. However, relatively little is known about a functioning complement system on intestinal mucosal surfaces. Herein, we report the local synthesis of complement component 3 (C3) in the gut, primarily by stromal cells. C3 is expressed upon commensal colonization and is regulated by the composition of the microbiota in healthy humans and mice, leading to an individual host's specific luminal C3 levels. The absence of membrane attack complex (MAC) components in the gut ensures that C3 deposition does not result in the lysis of commensals. Pathogen infection triggers the immune system to recruit neutrophils to the infection site for pathogen clearance. Basal C3 levels directly correlate with protection against enteric infection. Our study reveals the gut complement system as an innate immune mechanism acting as a vigilant sentinel that combats pathogens and spares commensals.

Microbiome induced complement synthesized in the gut protects against enteric infections

Canonically, complement is a serum-based host defense system that protects against systemic microbial invasion. Little is known about the production and function of complement components on mucosal surfaces. Here we show gut complement component 3 (C3), central to complement function, is regulated by the composition of the microbiota in healthy humans and mice, leading to host-specific gut C3 levels. Stromal cells in intestinal lymphoid follicles (LFs) are the predominant source of intestinal C3. During enteric infection with Citrobacter rodentium or enterohemorrhagic Escherichia coli, luminal C3 levels increase significantly and are required for protection. C. rodentium is remarkably more invasive to the gut epithelium of C3-deficient mice than of wild-type mice. In the gut, C3-mediated phagocytosis of C. rodentium functions to clear pathogens. Our study reveals that variations in gut microbiota determine individuals’ intestinal mucosal C3 levels, dominantly produced by LF stromal cells, which directly correlate with protection against enteric infection.

Highlights

Gut complement component 3 (C3) is induced by the microbiome in healthy humans and mice at a microbiota-specific level.Gut stromal cells located in intestinal lymphoid follicles are a major source of luminal C3 During enteric infections with Citrobacter rodentium or enterohemorrhagic Escherichia coli, gut luminal C3 levels increase and are required for protection. C. rodentium is significantly more invasive of the gut epithelium in C3-deficient mice when compared to WT mice. In the gut, C3-mediated opsonophagocytosis of C. rodentium functions to clear pathogens.

Maternal probiotic supplementation protects against PBDE-induced developmental, behavior and metabolic reprogramming in a sexually dimorphic manner: Role of gut microbiome

Polybrominated diphenyl ethers (PBDEs) are endocrine-disrupting persistent organic pollutants (POPs) used as flame retardants in a wide range of commercial applications. We have previously reported neurobehavioral and metabolic reprogramming produced by developmental PBDEs. PBDEs perturb the microbiome, an influencer of life-long health, while probiotic supplementation with Limosilactobacillus reuteri (LR) can avert neurobehavioral and endocrine disruption. We, therefore, tested the hypothesis that perinatal maternal LR supplementation would protect gut microbiome richness and diversity, developmental milestones, adult neurobehavior and metabolic homeostasis in PBDE-exposed offspring. C57BL/6N dams were orally exposed to a commercial penta-mixture of PBDEs, DE-71, at 0.1 mg/kg/day, or corn oil vehicle (VEH/CON) during gestation and lactation. Mice offspring received DE-71 or VEH/CON with or without co-administration of LR (ATCC-PTA-6475) indirectly via their mother from gestational day (GD) 0 until postnatal day (P)21 (Cohort 1), or continued to receive LR directly from P22 through adulthood (Cohort 2). Results of fecal 16S rRNA sequencing indicated age- and sex-dependent effects of DE-71 on gut microbial communities. Maternal LR treatment protected against DE-71-induced reduction in α-diversity in P22 females and against β-diversity alterations in P30 males. In females, DE-71 changed the relative abundance of specific bacterial taxa, such as Tenericutes and Cyanobacteria (elevated) and Deferribacterota (reduced). In males, several Firmicutes taxa were elevated, while Proteobacteria, Chlamydiae, and several Bacteroidota taxa were reduced. The number of disrupted taxa normalized by maternal LR supplementation was as follows: 100% in P22 females and 33% in males at P22 and 25% at P30. Maternal LR treatment protected against DE-71-induced delay of postnatal body weight gain in males and ameliorated the abnormal timing of incisor eruption in both sexes. Further, DE-71 produced exaggerated digging in both sexes as well as locomotor hyperactivity in females, effects that were mitigated by maternal LR only in females. Other benefits of LR therapy included normalization of glucose tolerance, insulin-to-glucose ratio and plasma leptin in adult DE-71 females (Cohort 2). This study provides evidence that probiotic supplementation can mitigate POP-induced reprogramming of neurodevelopment, adult neurobehavior, and glucose metabolism in association with modified gut microbial community structure in a sex-dependent manner.

Music exposure enhances resistance to Salmonella infection by promoting healthy gut microbiota

Music intervention is gaining recognition as a cost-effective therapeutic for improving human health. Despite its growing application, the mechanisms through which music exerts beneficial health effects remain largely unexplored. Here, we show that music can exert beneficial effects in mice through modulating gut microbiome composition. Adult mice were exposed to ambient noise, Mozart's Flute Quartet in D Major, K. 285, or white noise over a three-week period. Afterward, we observed treatment-specific changes in the community of gut commensal bacteria in these animals. Upon subsequent challenge with the bacterial pathogen Salmonella typhimurium, control groups exhibited significant weight loss and increased Salmonella colonization, whereas the Mozart-treated group did not. 16S ribosomal RNA gene sequencing revealed that the Mozart group showed a significant increase in Lactobacillus salivarius, a probiotic known for its antibacterial properties. Further experiments confirmed that L. salivarius mitigated Salmonella infection in mice and that L. salivarius acidified local environments in in vitro culture, thus inhibiting Salmonella growth. Additionally, mice exposed to Mozart consumed more food but showed similar body weight compared to the control groups. Behavioral assessments, including open field and object location tests, revealed that Mozart-treated mice were more active, less anxious, and exhibited enhanced spatial memory. Finally, Mozart exposure was shown to significantly boost colonization of administered L. salivarius and alter gut metabolite profiles. These findings suggest that music exposure fosters healthier gut microbiota, enhancing resistance to bacterial infections and highlighting the potential of music therapy as a novel strategy to combat drug-resistant pathogen infections.

IMPORTANCE

Music therapy is increasingly recognized as a low-cost approach to improving health, but how it works remains unclear. Our study demonstrates that music can positively influence health by altering the gut microbiome. In a mouse model, exposure to Mozart's Flute Quartet in D Major enhanced the gut microbiota, specifically increasing levels of the beneficial bacterium Lactobacillus salivarius. This probiotic protected mice from Salmonella infection by creating an acidic environment that inhibited pathogen growth. Mozart-treated mice also showed reduced anxiety, better spatial memory, and higher food intake without weight gain, suggesting the benefits of music exposure. These findings reveal a novel link between music, gut health, and disease resistance, suggesting that music therapy could be a promising strategy for enhancing gut microbiota and combating infections, including those caused by drug-resistant bacteria.