The gut microbiota induces Peyer's-patch-dependent secretion of maternal IgA into milk

Functional Assessment of a Bioprinted Immuno-Mimetic Peyer's Patch Recapitulating Gut-Associated Lymphoid Tissue

Gut immune models have attracted much interest in better understanding the microbiome in the human gastrointestinal tract. The gut-associated lymphoid tissue (GALT) has complex structures that interact with microorganisms, including the intestinal monolayer as a physiological barrier and the Peyer's patch (PP) involved in the immune system. Although essential for studying GALT and microbiome interactions, current research often uses simplified models that only recapitulate some components. In this study, GALT is recapitulated to consider the morphology and function of lymphocyte-containing PP beneath the intestinal monolayer and to analyze microbiome interaction. Using the bioprinting technique, a dome-shaped structure array for the PP is fabricated, and epithelial cells are cocultured to form the intestinal monolayer. The developed GALT model shows stable cell differentiation on the hydrogel while exhibiting durability against lipopolysaccharides. It also exhibits increased responsiveness to Escherichia coli, as indicated by elevated nitric oxide levels. In addition, the model underscores the critical role of GALT in maintaining bacterial coexistence and in facilitating immune defense against foreign antigens through the secretion of immunoglobulin A by lymphocyte spheroids. The proposed GALT model is expected to provide significant insights into studying the gut-immune system complexity and microbiome.

Extracellular adenosine triphosphate: A new gateway for food allergy mechanism research?

Although various studies have been conducted, the detailed mechanisms of food allergy remain a topic of ongoing debate. Recently, researchers have reported that extracellular adenosine triphosphate (eATP), a member of damage-associated molecular patterns secreted by stressed cells, plays a critical role in the progression of asthma and atopic dermatitis. These studies suggest that dysregulated eATP significantly influences various aspects of disease progression, from bodily sensitization to the emergence of clinical manifestations. Given the shared pathogenic mechanisms among asthma, atopic dermatitis, and food allergies, we hypothesize that eATP may also serve as a crucial regulator in the development of food allergies. To elucidate this hypothesis, we first summarize the evidence and limitations of food allergy theories, then discuss the roles of eATP in allergic diseases. We conclude with speculative insights into the potential influence of eATP on food allergy development, aiming to inspire further investigation into the molecular mechanisms of food allergies.

The right educational environment: Oral tolerance in early life

Oral tolerance promotes the suppression of immune responses to innocuous antigen and is primarily mediated by regulatory T cell (Tregs). The development of oral tolerance begins in early life during a "window of tolerance," which occurs around weaning and is mediated by components in breastmilk. Herein, we review the factors dictating this window and how Tregs are uniquely educated in early life. In early life, the translocation of luminal antigen for Treg induction is primarily dictated by goblet cell-associated antigen passages (GAPs). GAPs in the colon are negatively regulated by maternally-derived epidermal growth factor and the microbiota, restricting GAP formation to the "periweaning" period (postnatal day 11-21 in mice, 4-6 months in humans). The induction of solid food also promotes the diversification of the bacteria such that bacterially-derived metabolites known to promote Tregs-short-chain fatty acids, tryptophan metabolites, and bile acids-peak during the periweaning phase. Further, breastmilk immunoglobulins-IgA and IgG-regulate both microbial diversity and the interaction of microbes with the epithelium, further controlling which antigens are presented to T cells. Overall, these elements work in conjunction to induce a long-lived population of Tregs, around weaning, that are crucial for maintaining homeostasis in adults.

Male mice are susceptible to brain dysfunction induced by early-life acephate exposure

Background

Acephate is a widely used organophosphate insecticide. Exposure to endocrine-disrupting chemicals, such as acephate, can interfere with neurodevelopment in childhood, increasing the risk of higher brain dysfunction later in life. Furthermore, brain dysfunction may be related to chemical exposure-related disturbances in the gut microbiota. However, the effects of early acephate exposure on the brains of adult males and females as well as on the adult gut environment remain poorly understood.

Methods

This study investigated the effects of perinatal acephate exposure on the central nervous system and gut microbiota of mice, including sex differences and environmentally relevant concentrations. C57BL/6 N pups were exposed to acephate (0, 0.3, 10, and 300 ppm) via the dam in their drinking water from embryonic day (E) 11.5 to postnatal day 14. We examined its effects on the central nervous system of adult males and females.

Results

In the male treatment group, impairments in learning and memory were detected. Immunohistochemical analysis revealed a decrease in SOX2-, NeuN-, DCX-, and GFAP-positive cells in the hippocampal dentate gyrus in males compared to the control group, whereas GFAP-positive cells were fewer in females. In addition, gut microbiota diversity was reduced in both sexes in the experimental group.

Conclusion

Our study demonstrates that the effects of early-life exposure to acephate are more pronounced in males than in females and can lead to a lasting impact on adult behavior, even at low doses, and that the gut microbiota may reflect the brain environment.

Bacillus subtilis Feed Supplementation Combined with Oral E. coli Immunization in Sows as a Tool to Reduce Neonatal Diarrhea in Piglets

To investigate the effects of B. subtilis on the specific immune response of lactating sows to E. coli and the diarrhea rate in suckling piglets, thirty large white sows with similar farrowing dates were randomly divided into two groups: a feedback feeding (i.e., feeding a homogenate of intestinal contents and tissues from E. coli-infected piglets to sows; FB) group and a feedback feeding with B. subtilis (FB + BS) group. Serum, colostrum, and intestinal tissues from sows and piglets were collected to assess the immune response and intestinal barrier function at weaning. T and B cells from Peyer's patches (PPs) and mesenteric lymph nodes (MLNs) in lactating mice (with treatments consistent with the sows') were isolated to explore the underlying mechanism. The results showed that, compared with the FB group, the reproductive performance of sows and the growth performance of their offspring were effectively improved in the FB + BS group. Moreover, the levels of IgG/IgA and those of IgG/IgA against E. coli in the serum and colostrum of sows in the FB+BS group were increased (p < 0.05). Meanwhile, the ratio of CD4+/CD8+, CD4+CXCR5+PD1+, and B220+IgA+ cells in MLNs and PPs, and the IgA levels in the mammary glands of mice, were also increased in the FB + BS group (p < 0.05). Notably, in suckling piglets in the FB + BS group, the diarrhea rate was decreased (p < 0.05), and the intestinal barrier function and intestinal flora composition at weaning were significantly improved. Overall, these results indicated that B. subtilis feed supplementation combined with feedback feeding in pregnant and lactating sows can reduce diarrhea in suckling piglets by enhancing the maternal immune response against E. coli and intestinal barrier function in their offspring, improving survival rates and pre-weaning growth.

Broad specificity of monoclonal IgA (TEPC15-IgA) for enteric bacteria via phosphorylcholine-mediated interaction

Immunoglobulin A (IgA) is notable for its broad specificity toward multiple bacteria. Phosphorylcholine (PC) plays a role in the infection of pathogenic bacteria carrying PC and in the induction of IgA responses in the host immune system. The commercially available mouse monoclonal IgA, TEPC15-IgA, is a distinctive antibody with specificity for PC, warranting further exploration of its response to PC-bearing enteric bacteria. In this study, using 17 different enteric bacteria, including 3 aerobic and 14 anerobic bacteria that could be cultured in vitro, we confirmed that TEPC15-IgA recognizes 4 bacterial species: Lactobacillus taiwanensis, Limosilactobacillus frumenti, Streptococcus infantis, and Escherichia coli, although reactivity varied. Interestingly, TEPC15-IgA did not react with four of six Lactobacillus species used. Moreover, distinct target molecules associated with PC in L. taiwanensis and L. frumenti were evident, differing in molecular weight. These findings suggest that the natural generation of PC-specific IgA could prevent PC-mediated infections and potentially facilitate the formation of a microflora rich in indigenous bacteria with PC, particularly in the gastrointestinal tract.

The impact of high-IgE levels on metabolome and microbiome in experimental allergic enteritis

BACKGROUND

The pathological mechanism of the gastrointestinal forms of food allergies is less understood in comparison to other clinical phenotypes, such as asthma and anaphylaxis Importantly, high-IgE levels are a poor prognostic factor in gastrointestinal allergies.

METHODS

This study investigated how high-IgE levels influence the development of intestinal inflammation and the metabolome in allergic enteritis (AE), using IgE knock-in (IgEki) mice expressing high levels of IgE. In addition, correlation of the altered metabolome with gut microbiome was analysed.

RESULTS

Ovalbumin-sensitized and egg-white diet-fed (OVA/EW) BALB/c WT mice developed moderate AE, whereas OVA/EW IgEki mice induced more aggravated intestinal inflammation with enhanced eosinophil accumulation. Untargeted metabolomics detected the increased levels of N-tau-methylhistamine and 2,3-butanediol, and reduced levels of butyric acid in faeces and/or sera of OVA/EW IgEki mice, which was accompanied with reduced Clostridium and increased Lactobacillus at the genus level. Non-sensitized and egg-white diet-fed (NC/EW) WT mice did not exhibit any signs of AE, whereas NC/EW IgEki mice developed marginal degrees of AE. Compared to NC/EW WT mice, enhanced levels of lysophospholipids, sphinganine and sphingosine were detected in serum and faecal samples of NC/EW IgEki mice. In addition, several associations of altered metabolome with gut microbiome-for example Akkermansia with lysophosphatidylserine-were detected.

CONCLUSIONS

Our results suggest that high-IgE levels alter intestinal and systemic levels of endogenous and microbiota-associated metabolites in experimental AE. This study contributes to deepening the knowledge of molecular mechanisms for the development of AE and provides clues to advance diagnostic and therapeutic strategies of allergic diseases.

Maternal-driven immune education in offspring

Maternal environmental exposures, particularly during gestation and lactation, significantly influence the immunological development and long-term immunity of offspring. Mammalian immune systems develop through crucial inputs from the environment, beginning in utero and continuing after birth. These critical developmental windows are essential for proper immune system development and, once closed, may not be reopened. This review focuses on the mechanisms by which maternal exposures, particularly to pathogens, diet, and microbiota, impact offspring immunity. Mechanisms driving maternal-offspring immune crosstalk include transfer of maternal antibodies, changes in the maternal microbiome and microbiota-derived metabolites, and transfer of immune cells and cytokines via the placenta and breastfeeding. We further discuss the role of transient maternal infections, which are common during pregnancy, in providing tissue-specific immune education to offspring. We propose a "maternal-driven immune education" hypothesis, which suggests that offspring can use maternal encounters that occur during a critical developmental window to develop optimal immune fitness against infection and inflammation.

Longitudinal multi-omics analysis uncovers the altered landscape of gut microbiota and plasma metabolome in response to high altitude

BACKGROUND

Gut microbiota is significantly influenced by altitude. However, the dynamics of gut microbiota in relation to altitude remains undisclosed.

METHODS

In this study, we investigated the microbiome profile of 610 healthy young men from three different places in China, grouped by altitude, duration of residence, and ethnicity. We conducted widely targeted metabolomic profiling and clinical testing to explore metabolic characteristics.

RESULTS

Our findings revealed that as the Han individuals migrated from low altitude to high latitude, the gut microbiota gradually converged towards that of the Tibetan populations but reversed upon returning to lower altitude. Across different cohorts, we identified 51 species specifically enriched during acclimatization and 57 species enriched during deacclimatization to high altitude. Notably, Prevotella copri was found to be the most enriched taxon in both Tibetan and Han populations after ascending to high altitude. Furthermore, significant variations in host plasma metabolome and clinical indices at high altitude could be largely explained by changes in gut microbiota composition. Similar to Tibetans, 41 plasma metabolites, such as lactic acid, sphingosine-1-phosphate, taurine, and inositol, were significantly elevated in Han populations after ascending to high altitude. Germ-free animal experiments demonstrated that certain species, such as Escherichia coli and Klebsiella pneumoniae, which exhibited altitude-dependent variations in human populations, might play crucial roles in host purine metabolism.

CONCLUSIONS

This study provides insights into the dynamics of gut microbiota and host plasma metabolome with respect to altitude changes, indicating that their dynamics may have implications for host health at high altitude and contribute to host adaptation. Video Abstract.

Expression and Function of Mammary Epithelial Cell-Derived Immunoglobulins

Over the past 20 years, increasing evidence has demonstrated that immunoglobulins (Igs) can be widely generated from non B cells, including normal and malignant mammary epithelial cells. In normal breast tissue, the expression of IgG and IgA has been identified in epithelial cells of mammary glands during pregnancy and lactation, which can be secreted into milk, and might participate in neonatal immunity. On the other hand, non B-IgG is highly expressed in breast cancer cells, correlating with the poor prognosis of patients with breast cancer. Importantly, a specific group of IgG, bearing a unique N-linked glycan on the Asn162 site and aberrant sialylation modification at the end of the novel glycan (referred to as sialylated IgG (SIA-IgG)), has been found in breast cancer stem/progenitor-like cells. SIA-IgG can significantly promote the capacity of migration, invasiveness, and metastasis, as well as enhance self-renewal and tumorigenicity in vitro and in vivo. These findings suggest that breast epithelial cells can produce Igs with different biological activities under physiological and pathological conditions. During lactation, these Igs could be the main source of milk Igs to protect newborns from pathogenic infections, while under pathological conditions, they display oncogenic activity and promote the occurrence and progression of breast cancer.

Neonatal intestinal colonization of Streptococcus agalactiae and the multiple modes of protection limiting translocation

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a predominant pathogen of neonatal sepsis, commonly associated with early-onset neonatal sepsis. GBS has also been associated with cases of late-onset sepsis potentially originating from the intestine. Previous findings have shown GBS can colonize the infant intestinal tract as part of the neonatal microbiota. To better understand GBS colonization dynamics in the neonatal intestine, we collected stool and milk samples from prematurely born neonates for identification of potential pathogens in the neonatal intestinal microbiota. GBS was present in approximately 10% of the cohort, and this colonization was not associated with maternal GBS status, delivery route, or gestational weight. Interestingly, we observed the relative abundance of GBS in the infant stool negatively correlated with maternal IgA concentration in matched maternal milk samples. Using a preclinical murine model of GBS infection, we report that both vertical transmission and direct oral introduction resulted in intestinal colonization of GBS; however, translocation beyond the intestine was limited. Finally, vaccination of dams prior to breeding induced strong immunoglobulin responses, including IgA responses, which were associated with reduced mortality and GBS intestinal colonization. Taken together, we show that maternal IgA may contribute to infant immunity by limiting the colonization of GBS in the intestine.

Gut microbiota regulate migration of lymphocytes from gut to lung

The community of microorganisms known as gut microbiota that lives in the intestine confers significant health benefits on its host, primarily in the form of immunological homeostasis regulation. Gut microbiota not only can shape immune responses in the gut but also in other organs. This review focus on the gut-lung axis. Aberrant gut microbiota development is associated with greater lung disease susceptibility and respiratory disease induced by a variety of pathogenic bacteria. They are known to cause changes in gut microbiota. Recent research has found that immune cells in the intestine migrate to distant lung to exert anti-infective effects. Moreover, evidence indicates that the gut microbiota and their metabolites influence intestinal immune cells. Therefore, we suspect that intestine-derived immune cells may play a significant role against pulmonary pathogenic infections by receiving instructions from gut microbiota.

Gut epithelial barrier dysfunction in lupus triggers a differential humoral response against gut commensals

Introduction

Systemic lupus erythematosus is an autoimmune disease with multisystemic involvement including intestinal inflammation. Lupus-associated intestinal inflammation may alter the mucosal barrier where millions of commensals have a dynamic and selective interaction with the host immune system. Here, we investigated the consequences of the intestinal inflammation in a TLR7-mediated lupus model.

Methods

IgA humoral and cellular response in the gut was measured. The barrier function of the gut epithelial layer was characterised. Also, microbiota composition in the fecal matter was analysed as well as the systemic humoral response to differential commensals.

Results

The lupus-associated intestinal inflammation modifies the IgA+ B cell response in the gut-associated lymphoid tissue in association with dysbiosis. Intestinal inflammation alters the tight junction protein distribution in the epithelial barrier, which correlated with increased permeability of the intestinal barrier and changes in the microbiota composition. This permeability resulted in a differential humoral response against intestinal commensals.

Discussion

Lupus development can cause alterations in microbiota composition, allowing specific species to colonize only the lupus gut. Eventually, these alterations and the changes in gut permeability induced by intestinal inflammation could lead to bacterial translocation.

Immunoglobulins at the interface of the gut mycobiota and anti-fungal immunity

The dynamic and complex community of microbes that colonizes the intestines is composed of bacteria, fungi, and viruses. At the mucosal surfaces, immunoglobulins play a key role in protection against bacterial and fungal pathogens, and their toxins. Secretory immunoglobulin A (sIgA) is the most abundantly produced antibody at the mucosal surfaces, while Immunoglobulin G (IgG) isotypes play a critical role in systemic protection. IgA and IgG antibodies with reactivity to commensal fungi play an important role in shaping the mycobiota and host antifungal immunity. In this article, we review the latest evidence that establishes a connection between commensal fungi and B cell-mediated antifungal immunity as an additional layer of protection against fungal infections and inflammation.

Early Oral Administration of Ginseng Stem-Leaf Saponins Enhances the Peyer's Patch-Dependent Maternal IgA Antibody Response to a PEDV Inactivated Vaccine in Mice, with Gut Microbiota Involvement

Neonatal piglets during the first week of life are highly susceptible to porcine epidemic diarrhoea virus (PEDV) infection, with mortality rates reaching 80-100%. Passive lactogenic immunity remains the most effective way to protect neonates from infection. Although safe, inactivated vaccines provide little or no passive protection. Here, we administered ginseng stem-leaf saponins (GSLS) to mice before parenteral immunization with an inactivated PEDV vaccine to investigate the effect of GSLS on the gut-mammary gland (MG)-secretory IgA axis. Early oral GSLS administration potently increased PEDV-specific IgA plasma cell generation in the intestine, facilitated intestinal IgA plasma cell migration to the MG by enhancing the chemokine receptor (CCR)10-chemokine ligand (CCL)28 interaction, and ultimately promoted specific IgA secretion into milk, which was dependent on Peyer's patches (PPs). Additionally, GSLS improved the gut microbiota composition, especially increasing probiotic abundance, and these microflora members promoted the GSLS-enhanced gut-MG-secretory IgA axis response and were regulated by PPs. In summary, our findings highlight the potential of GSLS as an oral adjuvant for PEDV-inactivated vaccines and provide an attractive vaccination strategy for lactogenic immunity induction in sows. Further studies are required to evaluate the mucosal immune enhancement efficacy of GSLS in pigs.

Maternal provisions in type 1 diabetes: Evidence for both protective & pathogenic potential

Maternal influences on the immune health and development of an infant begin in utero and continue well into the postnatal period, shaping and educating the child's maturing immune system. Two maternal provisions include early microbial colonizers to initiate microbiota establishment and the transfer of antibodies from mother to baby. Maternal antibodies are a result of a lifetime of antigenic experience, reflecting the infection history, health and environmental exposure of the mother. These same factors are strong influencers of the microbiota, inexorably linking the two. Together, these provisions help to educate the developing neonatal immune system and shape lymphocyte repertoires, establishing a role for external environmental influences even before birth. In the context of autoimmunity, the transfer of maternal autoantibodies has the potential to be harmful for the child, sometimes targeting tissues and cells with devastating consequences. Curiously, this does not seem to apply to maternal autoantibody transfer in type 1 diabetes (T1D). Moreover, despite the rising prevalence of the disease, little research has been conducted on the effects of maternal dysbiosis or antibody transfer from an affected mother to her offspring and thus their relevance to disease development in the offspring remains unclear. This review seeks to provide a thorough evaluation of the role of maternal microorganisms and antibodies within the context of T1D, exploring both their pathogenic and protective potential. Although a definitive understanding of their significance in infant T1D development remains elusive at present, we endeavor to present what has been learned with the goal of spurring further interest in this important and intriguing question.

Programmed and environmental determinants driving neonatal mucosal immune development

The mucosal immune system of neonates goes through successive, non-redundant phases that support the developmental needs of the infant and ultimately establish immune homeostasis. These phases are informed by environmental cues, including dietary and microbial stimuli, but also evolutionary developmental programming that functions independently of external stimuli. The immune response to exogenous stimuli is tightly regulated during early life; thresholds are set within this neonatal "window of opportunity" that govern how the immune system will respond to diet, the microbiota, and pathogenic microorganisms in the future. Thus, changes in early-life exposure, such as breastfeeding or environmental and microbial stimuli, influence immunological and metabolic homeostasis and the risk of developing diseases such as asthma/allergy and obesity.

Galacto-oligosaccharides fed during gestation increase Rotavirus A specific antibodies in sow colostrum, modulate the microbiome, and reduce infectivity in neonatal piglets in a commercial farm setting

Introduction

Rotavirus A is a major cause of acute dehydrating diarrhea in neonatal pigs resulting in significant mortality, morbidity, reduced performance and economic loss. Commercially available prebiotic galacto-oligosaccharides are similar to those of mammalian milk and stimulate the development of the microbiota and immune system in neonates. Little is known about the effects of supplementing sows' diets with galacto-oligosaccharides during gestation. This study aimed to determine if dietary galacto-oligosaccharide supplementation during gestation could improve immunity, reduce rotavirus infection and modulate the microbiota in sows and neonates in a commercial farm setting with confirmed natural endemic rotavirus challenge.

Methods

In a randomized controlled trial, control sows received lactation diet with no galacto-oligosaccharide supplementation and test sows received lactation diet with 30 g/day galacto-oligosaccharide top-dressed into feed daily, seven days before farrowing. Colostrum was collected from sows 24 hours post-partum and tested for rotavirus specific antibodies. Fecal samples were collected from sows and piglets three days post-partum, tested for rotavirus A by qPCR and the microbiome composition assessed by 16s rRNA gene sequencing.

Results

Supplementation with galacto-oligosaccharides during gestation significantly increased rotavirus-specific IgG and IgA in sow colostrum and reduced the number of rotavirus positive piglet fecal samples. Abundance of potential pathogens Treponema and Clostridiales were higher in fecal samples from non-galacto-oligosaccharide fed sows, their piglets and rotavirus positive samples.

Discussion

This study demonstrates that galacto-oligosaccharide supplementation during gestation significantly increases rotavirus specific IgG and IgA in sow colostrum thereby reducing neonatal rotavirus infection and suppresses potential pathogenic bacteria in nursing sows and neonatal piglets.

Prevention of Metabolic Syndrome by Phytochemicals and Vitamin D

In recent years, attention has focused on the roles of phytochemicals in fruits and vegetables in maintaining and improving the intestinal environment and preventing metabolic syndrome. A high-fat and high-sugar diet, lack of exercise, and excess energy accumulation in the body can cause metabolic syndrome and induce obesity, diabetes, and disorders of the circulatory system and liver. Therefore, the prevention of metabolic syndrome is important. The current review shows that the simultaneous intake of phytochemicals contained in citruses and grapes together with vitamin D improves the state of gut microbiota and immunity, preventing metabolic syndrome and related diseases. Phytochemicals contained in citruses include polyphenols such as hesperidin, rutin, and naringin; those in grapes include quercetin, procyanidin, and oleanolic acid. The intake of these phytochemicals and vitamin D, along with prebiotics and probiotics, nurture good gut microbiota. In general, Firmicutes are obese-prone gut microbiota and Bacteroidetes are lean-prone gut microbiota; good gut microbiota nurture regulatory T cells, which suppress inflammatory responses and upregulate immunity. Maintaining good gut microbiota suppresses TNF-α, an inflammatory cytokine that is also considered to be a pathogenic contributor adipokine, and prevents chronic inflammation, thereby helping to prevent metabolic syndrome. Maintaining good gut microbiota also enhances adiponectin, a protector adipokine that prevents metabolic syndrome. For the prevention of metabolic syndrome and the reduction of various disease risks, the intake of phytochemicals and vitamin D will be important for human health in the future.

Crosstalk between Gut Microbiota and Host Immunity: Impact on Inflammation and Immunotherapy

Gut microbes and their metabolites are actively involved in the development and regulation of host immunity, which can influence disease susceptibility. Herein, we review the most recent research advancements in the gut microbiota-immune axis. We discuss in detail how the gut microbiota is a tipping point for neonatal immune development as indicated by newly uncovered phenomenon, such as maternal imprinting, in utero intestinal metabolome, and weaning reaction. We describe how the gut microbiota shapes both innate and adaptive immunity with emphasis on the metabolites short-chain fatty acids and secondary bile acids. We also comprehensively delineate how disruption in the microbiota-immune axis results in immune-mediated diseases, such as gastrointestinal infections, inflammatory bowel diseases, cardiometabolic disorders (e.g., cardiovascular diseases, diabetes, and hypertension), autoimmunity (e.g., rheumatoid arthritis), hypersensitivity (e.g., asthma and allergies), psychological disorders (e.g., anxiety), and cancer (e.g., colorectal and hepatic). We further encompass the role of fecal microbiota transplantation, probiotics, prebiotics, and dietary polyphenols in reshaping the gut microbiota and their therapeutic potential. Continuing, we examine how the gut microbiota modulates immune therapies, including immune checkpoint inhibitors, JAK inhibitors, and anti-TNF therapies. We lastly mention the current challenges in metagenomics, germ-free models, and microbiota recapitulation to a achieve fundamental understanding for how gut microbiota regulates immunity. Altogether, this review proposes improving immunotherapy efficacy from the perspective of microbiome-targeted interventions.

Alginate oligosaccharide ameliorates azithromycin-induced gut microbiota disorder via Bacteroides acidifaciens-FAHFAs and Bacteroides-TCA cycle axes

Alginate oligosaccharide is a kind of prebiotic with broad application prospects. However, little attention is paid to the recovery effect of alginate oligosaccharide on disordered intestinal microecology caused by azithromycin. Therefore, we evaluated the regulatory effect of alginate oligosaccharide and its compound on azithromycin-disturbed gut microbiota in mice via microbiome-metabolomics analysis. The gut microbiota analysis revealed that alginate oligosaccharide and its compound significantly increased the richness and diversity of the gut microbiota which were reduced by azithromycin, with an obvious enrichment of beneficial bacteria such as the Akkermansia genus and Bacteroides acidifaciens, and a remarkable decrease of pathogenic bacteria such as the Staphylococcus genus, which indicated its impact on the gut microbiota dysbiosis. Additionally, the effect of the alginate oligosaccharide compound on regulating the gut microbiota disorder is more significant than that of alginate oligosaccharide. The favorable effects of alginate oligosaccharide were confirmed by beneficial alterations in metabolic effector molecules, which indicated that alginate oligosaccharide and its compound improved metabolic homeostasis via the Bacteroides acidifaciens-fatty acid esters of hydroxy fatty acids (FAHFAs) axis and increasing the levels of the intermediate products of the tricarboxylic acid cycle (TCA cycle), such as citric acid, fumaric acid and α-ketoglutaric acid. Spearman correlation analysis showed that the contents of these three metabolites were also positively related to Bacteroides acidifaciens and Bacteroides sartorii populations, suggesting the potential regulatory role of the Bacteroides genus in energy balance through the TCA cycle. This study may provide an innovative dietary strategy for the regulation of intestinal microecological disorders caused by antibiotics, and reveal the prospect of alginate oligosaccharide as an intestinal microecological regulator.

Effect of seaweed feeding before calving on colostral IgA concentration in Japanese Black cows

In this study, we investigated the effect of feeding seaweed to Japanese Black cows before calving on IgA concentrations in colostrum. Seven Japanese Black breeding cows were used as test animals, with three cows in the seaweed-fed group (seaweed group) and four in the seaweed-non-fed group (control group). Each cow was fed 6 kg of sudangrass hay and 2.5 kg of compound feed twice daily (09:00 a.m. and 04:00 p.m.) as basal diets. Both groups had free access to water. In the seaweed group, commercially available seaweed feed was fed from 2 months before calving until the day of calving. The seaweed of 150 g/head/day was added to the basal diet at the morning feeding. Colostrum collected immediately after calving was used to measure IgA concentrations by ELISA. The IgA concentration in colostrum was significantly higher in the seaweed group than in the control group (P < 0.05). This suggested that feeding seaweed to Japanese Black cows before calving may increase IgA concentration in colostrum.

Maternal microbe-specific modulation of the offspring microbiome and development during pregnancy and lactation

The maternal microbiome is essential for the healthy growth and development of offspring and has long-term effects later in life. Recent advances indicate that the maternal microbiome begins to regulate fetal health and development during pregnancy. Furthermore, the maternal microbiome continues to affect early microbial colonization via birth and breastfeeding. Compelling evidence indicates that the maternal microbiome is involved in the regulation of immune and brain development and affects the risk of related diseases. Modulating offspring development by maternal diet and probiotic intervention during pregnancy and breastfeeding could be a promising therapy in the future. In this review, we summarize and discuss the current understanding of maternal microbiota development, perinatal microbial metabolite transfer, mother-to-infant microbial transmission during/after birth and its association with immune and brain development as well as corresponding diseases.

Limosilactobacillus reuteri FN041 prevents atopic dermatitis in pup mice by remodeling the ileal microbiota and regulating gene expression in Peyer’s patches after vertical transmission

Objectives

Limosilactobacillus reuteri FN041 is a potential probiotic bacterium isolated from breast milk in traditional farming and pastoral areas of China. The purpose of this study was to investigate the optimal intervention mode and potential mechanism of FN041 to prevent atopic dermatitis (AD) in mice.

Methods

In intervention mode I, FN041 was supplemented to dams during the late trimester and lactation and pups after weaning; in intervention mode II, FN041 was supplemented after pups were weaned. AD was induced in pups with MC903 plus ovalbumin on the ear after weaning.

Results

The effect of intervention mode I in preventing AD was significantly better than that of intervention mode II. Compared with the model group, the inflammatory response of the pup’s ears, the proportion of spleen regulatory T cells and the plasma IgE were significantly decreased in mice in intervention mode I. Furthermore, the intestinal mucosal barrier was enhanced, and the Shannon index of the ileal microbiota was significantly increased. The microbiota structure deviated from the AD controls and shifted toward the healthy controls according to the PCoA of unweighted UniFrac. The relative abundances of Limosilactobacillus, Faecalibacterium, Bifidobacterium, and Akkermansia in the ileum were significantly increased compared to the AD group. Based on RNA-seq analysis of pups’ Peyer’s patches (PPs), FN041 inhibits autoimmune pathways such as asthma and systemic lupus erythematosus and activates retinol metabolism and PPAR signaling pathways to reduce inflammatory responses. Intervention mode II also significantly reduced AD severity score, but the reduction was approximately 67% of that of intervention mode I. This may be related to its ineffective remodeling of the ileal microbiota.

Conclusion

Prenatal and postnatal administration of FN041 is an effective way to prevent AD in offspring, and its mechanism is related to remodeling of ileal microbiota and PPs immune response.

The Entero-Mammary Pathway and Perinatal Transmission of Gut Microbiota and SARS-CoV-2

COVID-19 is a severe respiratory disease threatening pregnant women, which increases the possibility of adverse pregnancy outcomes. Several recent studies have demonstrated the ability of SARS-CoV-2 to infect the mother enterocytes, disturbing the gut microbiota diversity. The aim of this study was to characterize the entero-mammary microbiota of women in the presence of the virus during delivery. Fifty mother−neonate pairs were included in a transversal descriptive work. The presence of SARS-CoV-2 RNA was detected in nasopharyngeal, mother rectal swabs (MRS) and neonate rectal swabs (NRS) collected from the pairs, and human colostrum (HC) samples collected from mothers. The microbiota diversity was characterized by high-throughput DNA sequencing of V3-16S rRNA gene libraries prepared from HC, MRS, and NRS. Data were analyzed with QIIME2 and R. Our results indicate that several bacterial taxa are highly abundant in MRS positive for SARS-CoV-2 RNA. These bacteria mostly belong to the Firmicutes phylum; for instance, the families Bifidobacteriaceae, Oscillospiraceae, and Microbacteriaceae have been previously associated with anti-inflammatory effects, which could explain the capability of women to overcome the infection. All samples, both positive and negative for SARS-CoV-2, featured a high abundance of the Firmicutes phylum. Further data analysis showed that nearly 20% of the bacterial diversity found in HC was also identified in MRS. Spearman correlation analysis highlighted that some genera of the Proteobacteria and Actinobacteria phyla were negatively correlated with MRS and NRS (p < 0.005). This study provides new insights into the gut microbiota of pregnant women and their potential association with a better outcome during SARS-CoV-2 infection.

Importance of Breed, Parity and Sow Colostrum Components on Litter Performance and Health

The aims of this study were to investigate the effect of breed and parity on colostrum components, and to associate sow breed, parity, and colostrum components with survival, growth, and the occurrence of diarrhoea of their litters. In Experiment 1, 64 sows (Duroc = 13; Landrace = 17 and Large White = 34) were included. In Experiment 2, 71 sows with different parities (1 = 10; 2 = 16; 3 = 13; 4 = 12; ≥5 = 20) were included. The number (N) of live piglets, litter body weight (Experiment 1), and the occurrence of diarrhoea (Experiment 1) were recorded at farrowing, at 2−3 days of age, and at weaning. Colostrum was analysed for proximate composition, immunoglobulins (Igs), and somatic cell count (SCC). Stepwise regressions and ANOVA models were used to associate breed, parity, and colostrum components with litter performance. The Duroc breed had the highest IgG and IgA (p < 0.005). Gilts had a higher fat% and SCC (p< 0.0001); these compounds were positively correlated (r = 0.45). Increased IgA tended to increase the N of weaned piglets (p = 0.058) and reduce litter diarrhoea (p = 0.021). The SCC increased the N of weaned piglets (p = 0.031). Overall, this study confirmed that breed and parity can influence the colostrum composition and highlighted the key role of Igs and somatic cells in piglet health.

Effect of 6‐n‐propyl‐2‐thiouracil or dexamethasone administration on the responses of antimicrobial components in goat milk to intramammary lipopolysaccharide infusion

Heat stress impacts the immune system of dairy animals by altering the hypothalamic-pituitary-adrenal axis and thyroid function, leading to conditions such as hypothyroidism and hypercortisolism. This study aimed to elucidate the effect of hypothyroidism and hypercortisolism on the response of mammary innate immune function to inflammation caused by Escherichia coli in dairy goats. To induce hypothyroidism and hypercortisolism, we administered 6-n-propyl-2-thiouracil (PTU; for 21 days) and dexamethasone (DEX; for 5 days), respectively, to six goats each; six goats without treatment were used as the control group. After treatment, lipopolysaccharide (LPS) from E. coli O111 was infused into the mammary gland. Somatic cell counts (SCC) and levels of lactoferrin (LF), S100A7, immunoglobulin A (IgA), and interleukin-8 (IL-8) in milk until 7 days after LPS infusion were measured. An increase in SCC after LPS infusion was inhibited in both PTU and DEX groups, and an increase in LF after LPS infusion was inhibited in PTU group, compared with that in the control group. The results of the present study suggest that the recruitment of neutrophils and LF production decreased under hypothyroidism or hypercortisolism, which may be one of the causes underlying increased incidence of mastitis in dairy animals under heat stress conditions.

Intestinal Dysbiosis in the Infant and the Future of Lacto-Engineering to Shape the Developing Intestinal Microbiome

PURPOSE

The goal of this study was to review the role of human milk in shaping the infant intestinal microbiota and the potential of human milk bioactive molecules to reverse trends of increasing intestinal dysbiosis and dysbiosis-associated diseases.

METHODS

This narrative review was based on recent and historic literature.

FINDINGS

Human milk immunoglobulins, oligosaccharides, lactoferrin, lysozyme, milk fat globule membranes, and bile salt-stimulating lipase are complex multifunctional bioactive molecules that, among other important functions, shape the composition of the infant intestinal microbiota.

IMPLICATIONS

The co-evolution of human milk components and human milk-consuming commensal anaerobes many thousands of years ago resulted in a stable low-diversity infant microbiota. Over the past century, the introduction of antibiotics and modern hygiene practices plus changes in the care of newborns have led to significant alterations in the intestinal microbiota, with associated increases in risk of dysbiosis-associated disease. A better understanding of mechanisms by which human milk shapes the intestinal microbiota of the infant during a vulnerable period of development of the immune system is needed to alter the current trajectory and decrease intestinal dysbiosis and associated diseases.