Gut microbiota remodeling reverses aging-associated inflammation and dysregulation of systemic bile acid homeostasis in mice sex-specifically

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

With the rapidly aging human population, age-related cognitive decline and dementia are becoming increasingly prevalent worldwide. Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota, microbial metabolites, and the functions of astrocytes. The microbiota-gut-brain axis has been the focus of multiple studies and is closely associated with cognitive function. This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases. This article also summarizes the gut microbiota components that affect astrocyte function, mainly through the vagus nerve, immune responses, circadian rhythms, and microbial metabolites. Finally, this article summarizes the mechanism by which the gut microbiota-astrocyte axis plays a role in Alzheimer's and Parkinson's diseases. Our findings have revealed the critical role of the microbiota-astrocyte axis in age-related cognitive decline, aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.

ICAM-1 may promote the loss of dopaminergic neurons by regulating inflammation in MPTP-induced Parkinson's disease mouse models

Parkinson's disease (PD) is a chronic neurodegenerative disease with unclear pathogenesis that involves neuroinflammation and intestinal microbial dysbiosis. Intercellular adhesion molecule-1 (ICAM-1), an inflammatory marker, participates in neuroinflammation during dopaminergic neuronal damage. However, the explicit mechanisms of action of ICAM-1 in PD have not been elucidated. We established a subacute PD mouse model by the intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and observed motor symptoms and gastrointestinal dysfunction in mice. Immunofluorescence was used to examine the survival of dopaminergic neurons, expression of microglial and astrocyte markers, and intestinal tight junction-associated proteins. Then, we use 16 S rRNA sequencing to identify alterations in the microbiota. Our findings revealed that ICAM-1-specific antibody (Ab) treatment relieved behavioural defects, gastrointestinal dysfunction, and dopaminergic neuronal death in MPTP-induced PD mice. Further mechanistic investigations indicated that ICAM-1Ab might suppress neuroinflammation by inhibiting the activation of astrocytes and microglia in the substantia nigra and relieving colon barrier impairment and intestinal inflammation. Furthermore, 16 S rRNA sequencing revealed that the relative abundances of bacterial Firmicutes, Clostridia, and Lachnospiraceae were elevated in the PD mice. However, ICAM-1Ab treatment ameliorated the MPTP-induced disorders in the intestinal microbiota. Collectively, we concluded that the suppressing ICAM-1 might lead to the a significant decrease of inflammation and restore the gut microbial community, thus ameliorating the damage of DA neurons.

Dietary emulsifier polysorbate 80 exposure accelerates age-related cognitive decline

Gut microbial homeostasis is crucial for the health of cognition in elderly. Previous study revealed that polysorbate 80 (P80) as a widely used emulsifier in food industries and pharmaceutical formulations could directly alter the human gut microbiota compositions. However, whether long-term exposure to P80 could accelerate age-related cognitive decline via gut-brain axis is still unknown. Accordingly, in this study, we used the senescence accelerated mouse prone 8 (SAMP8) mouse model to investigate the effects of the emulsifier P80 intake (1 % P80 in drinking water for 12 weeks) on gut microbiota and cognitive function. Our results indicated that P80 intake significantly exacerbated cognitive decline in SAMP8 mice, along with increased brain pathological proteins deposition, disruption of the blood-brain barrier and activation of microglia and neurotoxic astrocytes. Besides, P80 intake could also induce gut microbiota dysbiosis, especially the increased abundance of secondary bile acids producing bacteria, such as Ruminococcaceae, Lachnospiraceae, and Clostridium scindens. Moreover, fecal microbiota transplantation from P80 mice into 16-week-old SAMP8 mice could also exacerbated cognitive decline, microglia activation and intestinal barrier impairment. Intriguingly, the alterations of gut microbial composition significantly affected bile acid metabolism profiles after P80 exposure, with markedly elevated levels of deoxycholic acid (DCA) in serum and brain tissue. Mechanically, DCA could activate microglial and promote senescence-associated secretory phenotype production through adenosine triphosphate-binding cassette transporter A1 (ABCA1) importing lysosomal cholesterol. Altogether, the emulsifier P80 accelerated cognitive decline of aging mice by inducing gut dysbiosis, bile acid metabolism alteration, intestinal barrier and blood brain barrier disruption as well as neuroinflammation. This study provides strong evidence that dietary-induced gut microbiota dysbiosis may be a risk factor for age-related cognitive decline.

Bile acid metabolism in health and ageing-related diseases

Bile acids (BAs) have surpassed their traditional roles as lipid solubilizers and regulators of BA homeostasis to emerge as important signalling molecules. Recent research has revealed a connection between microbial dysbiosis and metabolism disruption of BAs, which in turn impacts ageing-related diseases. The human BAs pool is primarily composed of primary BAs and their conjugates, with a smaller proportion consisting of secondary BAs. These different BAs exert complex effects on health and ageing-related diseases through several key nuclear receptors, such as farnesoid X receptor and Takeda G protein-coupled receptor 5. However, the underlying molecular mechanisms of these effects are still debated. Therefore, the modulation of signalling pathways by regulating synthesis and composition of BAs represents an interesting and novel direction for potential therapies of ageing-related diseases. This review provides an overview of synthesis and transportion of BAs in the healthy body, emphasizing its dependence on microbial community metabolic capacity. Additionally, the review also explores how ageing and ageing-related diseases affect metabolism and composition of BAs. Understanding BA metabolism network and the impact of their nuclear receptors, such as farnesoid X receptor and G protein-coupled receptor 5 agonists, paves the way for developing therapeutic agents for targeting BA metabolism in various ageing-related diseases, such as metabolic disorder, hepatic injury, cardiovascular disease, renal damage and neurodegenerative disease.

Chrysanthemum morifolium Ramat extract and probiotics combination ameliorates metabolic disorders through regulating gut microbiota and PPARα subcellular localization

BACKGROUND

Chrysanthemum morifolium Ramat, a traditional Chinese medicine, has the effects on liver clearing, vision improving, and anti-inflammation. C. morifolium and probiotics have been individually studied for their beneficial effects on metabolic diseases. However, the underlying molecular mechanisms were not completely elucidated. This study aims to elucidate the potential molecular mechanisms of C. morifolium and probiotics combination (CP) on alleviating nonalcoholic fatty liver disease (NAFLD) and the dysregulation of glucose metabolism in high-fat diet (HFD)-fed mice.

METHODS

The therapeutic effect of CP on metabolism was evaluated by liver histology and serum biochemical analysis, as well as glucose tolerance test. The impact of CP on gut microbiota was analyzed by 16S rRNA sequencing and fecal microbiota transplantation. Hepatic transcriptomic analysis was performed with the key genes and proteins validated by RT-qPCR and western blotting. In addition, whole body Pparα knockout (Pparα-/-) mice were used to confirm the CP-mediated pathway.

RESULTS

CP supplementation ameliorated metabolic disorders by reducing body weight and hepatic steatosis, and improving glucose intolerance and insulin resistance in HFD fed mice. CP intervention mitigated the HFD-induced gut microbiota dysbiosis, which contributed at least in part, to the beneficial effect of improving glucose metabolism. In addition, hepatic transcriptomic analysis showed that CP modulated the expression of genes associated with lipid metabolism. CP downregulated the mRNA level of lipid droplet-binding proteins, such as Cidea and Cidec in the liver, leading to more substrates for fatty acid oxidation (FAO). Meanwhile, the expression of CPT1α, the rate-limiting enzyme of FAO, was significantly increased upon CP treatment. Mechanistically, though CP didn't affect the total PPARα level, it promoted the nuclear localization of PPARα, which contributed to the reduced expression of Cidea and Cidec, and increased expression of CPT1α, leading to activated FAO. Moreover, whole body PPARα deficiency abolished the anti-NAFLD effect of CP, suggesting the importance of PPARα in CP-mediated beneficial effect.

CONCLUSION

This study revealed the hypoglycemic and hepatoprotective effect of CP by regulating gut microbiota composition and PPARα subcellular localization, highlighting its potential for therapeutic candidate for metabolic disorders.

Variations in seminal microbiota and their functional implications in chickens adapted to high-altitude environments

Seminal fluid, once believed to be sterile, is now recognized as constituting a complex and dynamic environment inhabited by a diverse community of micro-organisms. However, research on the seminal microbiota in chickens is limited, and microbiota variations among different chicken breeds remain largely unexplored. In this study, we collected semen samples from Beijing You Chicken (BYC) and Tibetan Chicken (TC) and explored the characteristics of the microbiota using 16S rRNA gene sequencing. Additionally, we collected cloacal samples from the TC to control for environmental contamination. The results revealed that the microbial communities in the semen were significantly different from those in the cloaca. Firmicutes and Actinobacteriota were the predominant phyla in BYC and TC semen, respectively, with Lactobacillus and Phyllobacterium being the dominant genera in each group. Additionally, the seminal microbiota of BYC exhibited greater richness and evenness than that of TC. Principal coordinate analysis (PCoA) indicated significant intergroup differences between the seminal microbiotas of BYC and TC. Subsequently, by combining linear discriminant analysis effect size and random forest analyses, we identified Lactobacillus as the predominant microorganism in BYC semen, whereas Phyllobacterium dominated in TC semen. Furthermore, co-occurrence network analysis revealed a more intricate network in the BYC group than in the TC group. Additionally, unique microbial functional characteristics were observed in each breed, with TC exhibiting metabolic features potentially associated with their ability to adapt to high-altitude environments. The results of this study emphasized the unique microbiota present in chicken semen, which may be influenced by genetics and evolutionary history. Significant variations were observed between low-altitude and high-altitude breeds, highlighting the breed-specific implications of the seminal microbiota for reproduction and high-altitude adaptation.

Increased intestinal bile acid absorption contributes to age-related cognitive impairment

Cognitive impairment in the elderly is associated with alterations in bile acid (BA) metabolism. In this study, we observe elevated levels of serum conjugated primary bile acids (CPBAs) and ammonia in elderly individuals, mild cognitive impairment, Alzheimer's disease, and aging rodents, with a more pronounced change in females. These changes are correlated with increased expression of the ileal apical sodium-bile acid transporter (ASBT), hippocampal synapse loss, and elevated brain CPBA and ammonia levels in rodents. In vitro experiments confirm that a CPBA, taurocholic acid, and ammonia induced synaptic loss. Manipulating intestinal BA transport using ASBT activators or inhibitors demonstrates the impact on brain CPBA and ammonia levels as well as cognitive decline in rodents. Additionally, administration of an intestinal BA sequestrant, cholestyramine, alleviates cognitive impairment, normalizing CPBAs and ammonia in aging mice. These findings highlight the potential of targeting intestinal BA absorption as a therapeutic strategy for age-related cognitive impairment.

Structural and functional alteration of the gut microbiota in elderly patients with hyperlipidemia

Objective

To investigate the structure, composition, and functions of the gut microbiota in elderly patients with hyperlipidemia.

Methods

Sixteen older patients diagnosed with hyperlipidemia (M group) and 10 healthy, age-matched normal volunteers (N group) were included. These groups were further subdivided by sex into the male normal (NM, n = 5), female normal (NF, n = 5), male hyperlipidemia (MM, n = 8), and female hyperlipidemia (MF, n = 8) subgroups. Stool samples were collected for high-throughput sequencing of 16S rRNA genes. Blood samples were collected for clinical biochemical index testing.

Results

Alpha- and beta-diversity analyses revealed that the structure and composition of the gut microbiota were significantly different between the M and N groups. The relative abundances of Bacteroides, Parabacteroides, Blautia, Peptococcus, and Bifidobacterium were significantly decreased, while those of Lactobacillus, Helicobacter, and Desulfovibrio were significantly higher in the M group. There were also significant sex-related differences in microbial structure between the NM and NF groups, and between the MM and MF groups. Through functional prediction with PICRUSt 2, we observed distinct between-group variations in metabolic pathways associated with the gut microbiota and their impact on the functionality of the nervous system. Pearson's correlation coefficient was used as a distance metric to build co-abundance networks. A hypergeometric test was used to detect taxonomies with significant enrichment in specific clusters. We speculated that modules with Muribaculaceae and Lachnospiraceae as the core microbes play an important ecological role in the intestinal microbiota of the M group. The relative intestinal abundances of Agathobacter and Faecalibacterium in the M group were positively correlated with serum triglyceride and low-density lipoprotein levels, while the relative abundance of Bifidobacterium was negatively correlated with the serum lipoprotein a level.

The gut microbiome from middle-aged women with depression modulates depressive-like behaviors and plasma fatty acid metabolism in female middle-aged mice

BACKGROUND

Intestinal dysbacteriosis has frequently been involved in the context of depression. Nonetheless, only scant information is available about the features and functional changes of gut microbiota in female middle-aged depression (MAD).

OBJECTIVE

This study aims to explore whether there are characteristic changes in the gut microbes of female MAD and whether these changes are associated with depressive-like behaviors. Meanwhile, this study observed alterations in the lipid metabolism function of gut microbes and further examined changes in plasma medium- and long-chain fatty acids (MLCFAs) in mice that underwent fecal microbiota transplantation (FMT).

METHODS

Stool samples obtained from 31 MAD, along with 24 healthy individuals (HC) were analyzed by 16 S rRNA gene sequencing. Meanwhile, 14-month-old female C57BL/6J mice received antibiotic cocktails and then oral gavage of the microbiota suspension of MAD or HC for 3 weeks to reconstruct gut microbiota. The subsequent depressive-like behaviors, the composition of gut microbiota, as well as MLCFAs in the plasma were evaluated.

RESULTS

A noteworthy disruption in gut microbial composition in MAD individuals compared to HC was observed. Several distinct bacterial taxa, including Dorea, Butyricicoccus, and Blautia, demonstrated associations with the demographic variables. A particular microbial panel encompassing 49 genera effectively differentiated MAD patients from HC (AUC = 0.82). Fecal microbiome transplantation from MAD subjects led to depressive-like behaviors and dysfunction of plasma MLCFAs in mice.

CONCLUSIONS

These findings suggest that microbial dysbiosis is linked to the pathogenesis of MAD, and its role may be associated with the regulation of MLCFAs metabolism.

Gut Microbiota Shape Oligodendrocyte Response after Traumatic Brain Injury

White matter injury (WMI) is thought to be a major contributor to long-term cognitive dysfunctions after traumatic brain injury (TBI). This damage occurs partly due to apoptotic death of oligodendrocyte lineage cells (OLCs) after the injury, triggered directly by the trauma or in response to degenerating axons. Recent research suggests that the gut microbiota modulates the inflammatory response through the modulation of peripheral immune cell infiltration after TBI. Additionally, T-cells directly impact OLCs differentiation and proliferation. Therefore, we hypothesized that the gut microbiota plays a critical role in regulating the OLC response to WMI influencing T-cells differentiation and activation. Gut microbial depletion early after TBI chronically reduced re-myelination, acutely decreased OLCs proliferation, and was associated with increased myelin debris accumulation. Surprisingly, the absence of T-cells in gut microbiota depleted mice restored OLC proliferation and remyelination after TBI. OLCs co-cultured with T-cells derived from gut microbiota depleted mice resulted in impaired proliferation and increased expression of MHC-II compared with T cells from control-injured mice. Furthermore, MHC-II expression in OLCs appears to be linked to impaired proliferation under gut microbiota depletion and TBI conditions. Collectively our data indicates that depletion of the gut microbiota after TBI impaired remyelination, reduced OLCs proliferation with concomitantly increased OLC MHCII expression and required the presence of T cells. This data suggests that T cells are an important mechanistic link by which the gut microbiota modulate the oligodendrocyte response and white matter recovery after TBI.

Dietary Methionine Restriction Improves Gut Health and Alters the Plasma Metabolomic Profile in Rats by Modulating the Composition of the Gut Microbiota

Dietary methionine restriction (MetR) offers an integrated set of beneficial health effects, including delaying aging, extending health span, preventing fat accumulation, and reducing oxidative stress. This study aimed to investigate whether MetR exerts entero-protective effects by modulating intestinal flora, and the effect of MetR on plasma metabolites in rats. Rats were fed diets containing 0.86% methionine (CON group) and 0.17% methionine (MetR group) for 6 weeks. Several indicators of inflammation, gut microbiota, plasma metabolites, and intestinal barrier function were measured. 16S rRNA gene sequencing was used to analyze the cecal microbiota. The MetR diet reduced the plasma and colonic inflammatory factor levels. The MetR diet significantly improved intestinal barrier function by increasing the mRNA expression of tight junction proteins, such as zonula occludens (ZO)-1, claudin-3, and claudin-5. In addition, MetR significantly increased the levels of short-chain fatty acids (SCFAs) by increasing the abundance of SCFAs-producing Erysipclotxichaceae and Clostridium_sensu_stricto_1 and decreasing the abundance of pro-inflammatory bacteria Proteobacteria and Escherichia-Shigella. Furthermore, MetR reduced the plasma levels of taurochenodeoxycholate-7-sulfate, taurocholic acid, and tauro-ursodeoxycholic acid. Correlation analysis identified that colonic acetate, total colonic SCFAs, 8-acetylegelolide, collettiside I, 6-methyladenine, and cholic acid glucuronide showed a significant positive correlation with Clostridium_sensu_stricto_1 abundance but a significant negative correlation with Escherichia-Shigella and Enterococcus abundance. MetR improved gut health and altered the plasma metabolic profile by regulating the gut microbiota in rats.

β-Nicotinamide mononucleotide supplementation prolongs the lifespan of prematurely aged mice and protects colon function in ageing mice

Ageing is defined as the degeneration of physiological functions in numerous tissues and organs of an organism, which occurs with age. As we age, the gut undergoes a series of changes and weaknesses that may contribute to overall ageing. Emerging evidence suggests that β-nicotinamide mononucleotide (NMN) plays a role in regulating intestinal function, but there is still a lack of literature on its role in maintaining the colon health of ageing mice. In our research, Zmpste24-/- mice proved that NMN prolonged their life span and delayed senescence. This study was designed to investigate the effects of long-term intervention on regulating colon function in ageing mice. Our results indicated that NMN improved the pathology of intestinal epithelial cells and intestinal permeability by upregulating the expression of intestinal tight junction proteins and the number of goblet cells, increasing the release of anti-inflammatory factors, and increasing beneficial intestinal bacteria. NMN increased the expression of the proteins SIRT1, NMNAT2, and NMNAT3 and decreased the expression of the protein P53. It also regulated the activity of ISCs by increasing Wnt/β-catenin and Lgr5. Our findings also revealed that NMN caused a significant increase in the relative abundance of Akkermansia muciniphila and Bifidobacterium pseudolongum and notable differences in metabolic pathways related to choline metabolism in cancer. In summary, NMN supplementation can delay frailty in old age, aid healthy ageing, and delay gut ageing.

Achieving healthy aging through gut microbiota-directed dietary intervention: Focusing on microbial biomarkers and host mechanisms

BACKGROUND

Population aging has become a primary global public health issue, and the prevention of age-associated diseases and prolonging healthy life expectancies are of particular importance. Gut microbiota has emerged as a novel target in various host physiological disorders including aging. Comprehensive understanding on changes of gut microbiota during aging, in particular gut microbiota characteristics of centenarians, can provide us possibility to achieving healthy aging or intervene pathological aging through gut microbiota-directed strategies.

AIM OF REVIEW

This review aims to summarize the characteristics of the gut microbiota associated with aging, explore potential biomarkers of aging and address microbiota-associated mechanisms of host aging focusing on intestinal barrier and immune status. By summarizing the existing effective dietary strategies in aging interventions, the probability of developing a diet targeting the gut microbiota in future is provided.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three key notions: Firstly, gut microbiota has become a new target for regulating health status and lifespan, and its changes are closely related to age. Thus, we summarized aging-associated gut microbiota features at the levels of key genus/species and important metabolites through comparing the microbiota differences among centenarians, elderly people and younger people. Secondly, exploring microbiota biomarkers related to aging and discussing future possibility using dietary regime/components targeted to aging-related microbiota biomarkers promote human healthy lifespan. Thirdly, dietary intervention can effectively improve the imbalance of gut microbiota related to aging, such as probiotics, prebiotics, and postbiotics, but their effects vary among.

Astragalus polysaccharide attenuates nonalcoholic fatty liver disease through THDCA in high-fat diet-fed mice

ETHNOPHARMACOLOGICAL RELEVANCE

Astragalus polysaccharide (APS) extracted from Astragalus membranaceus (Fisch.) Bunge was proven to be effective in preventing high-fat diet (HFD) induced nonalcoholic fatty liver disease (NAFLD). However, the exact mechanisms were not completely elucidated.

AIM OF THE STUDY

The aim was to reveal the mechanisms of APS on preventing NAFLD from the aspects of regulating bile acids (BAs) homeostasis.

MATERIALS AND METHODS

Serum and liver BAs in HFD fed mice with or without APS intervention were quantified with an ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) system. The effect of APS on hepatic proteins involved in BAs synthesis were analyzed with Western blot. Finally, the effect of identified taurohyodeoxycholic acid (THDCA) that was significantly increased by APS on hepatic triglyceride (TG) accumulation was explored in vivo and in vitro.

RESULTS

APS regulated serum and liver BA profiles in HFD fed mice, especially increased serum THDCA. The levels of hepatic cholesterol 7a-hydroxylase (CYP7A1) and sterol 12a-hydroxylase (CYP8B1) which catalyzed the classical BAs synthesis pathway were significantly decreased by APS, while oxysterol 7a-hydroxylase (CYP7B1) which catalyzed the alternative BAs synthesis pathway was significantly increased by APS. THDCA reduced HFD-induced hepatic lipid accumulation and improved glucose homeostasis in mice, and decreased TG level in palmitic acid/oleic acid treated alpha mouse liver 12 (AML-12) cells. THDCA significantly downregulated the protein level of cluster of differentiation 36 (CD36) involved in fatty acid transport into the liver. Importantly, THDCA showed similar effect with APS in upregulating hepatic CYP7B1 and downregulating CYP7A1.

CONCLUSION

This study revealed the protective effect of APS on NAFLD was associated with the regulation on BA profiles, and proved the potential anti-NAFLD effect of THDCA, highlighting the involvement of BA metabolism in efficacy of herb-derived polysaccharides on metabolism.

Sex differences and individual variability in the captive Jamaican fruit bat (Artibeus jamaicensis) intestinal microbiome and metabolome

The intestinal microbiome plays an important role in mammalian health, disease, and immune function. In light of this function, recent studies have aimed to characterize the microbiomes of various bat species, which are noteworthy for their roles as reservoir hosts for several viruses known to be highly pathogenic in other mammals. Despite ongoing bat microbiome research, its role in immune function and disease, especially the effects of changes in the microbiome on host health, remains nebulous. Here, we describe a novel methodology to investigate the intestinal microbiome of captive Jamaican fruit bats (Artibeus jamaicensis). We observed a high degree of individual variation in addition to sex- and cohort-linked differences. The intestinal microbiome was correlated with intestinal metabolite composition, possibly contributing to differences in immune status. This work provides a basis for future infection and field studies to examine in detail the role of the intestinal microbiome in antiviral immunity.

The intestinal microbiota exerts a sex-specific influence on neuroinflammation in a Parkinson's disease mouse model

Parkinson's disease (PD) is a neurodegenerative disorder characterised by chronic and progressive symptoms; it is more prevalent in men than in women. The sex-specific influence of the intestinal microbiota has been associated with some neurodegenerative diseases, but the relationship with PD is currently unclear. In this study, we treated mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to establish a PD mouse model, and we utilised an antibiotic cocktail (Abx) to deplete the intestinal microbiota to evaluate the influence of the intestinal microbiota on male and female PD mice. MPTP treatment obviously caused bradykinesia and low mobility in female and male mice. Meanwhile, Abx treatment exerted a greater effect on male mice than female mice. Western blotting and immunofluorescence revealed that male mice treated with MPTP had higher expression of α-synuclein and proteins related to neuroinflammation and intestinal inflammation based on activation of glial cells and the TLR4-MyD88 signalling pathway. The sex-specific differences could be due to the different composition of the intestinal microbiota. Specifically, female mice had significantly higher abundance of Allobaculum, Turicibacter and Ruminococcus than male mice. Moreover, the abundance of the probiotic genus Bifidobacterium showed opposite trends in male and female mice. Our results indicate that the intestinal microbiota has an important effect on PD mice, especially male mice, by influencing neuroinflammation through the microbiota-gut-brain axis. In the future, there should be a focus on providing more reliable evidence for the pathogenesis and precise treatment of PD.

Review on chronic metabolic diseases surrounding bile acids and gut microbiota: What we have explored so far

Bile acid, the final product of cholesterol breakdown, functions as a complex regulator and signaling factor in human metabolism. Chronic metabolic diseases pose significant medical challenges. Growing research underscores bile acids' capacity to enhance metabolism via diverse pathways, regulating disorders and offering treatment potential. Numerous bile-acid-triggered pathways have become treatment targets. This review outlines bile acid synthesis, its role as a signal in chronic metabolic diseases, and highlights its interaction with gut microbiota in different metabolic conditions. Exploring host-bacteria-bile acid links emerges as a valuable future research direction with clinical implications.

Co-Housing and Fecal Microbiota Transplantation: Technical Support for TCM Herbal Treatment of Extra-Intestinal Diseases Based on Gut Microbial Ecosystem Remodeling

Dysregulation of the gut microbial ecosystem (GME) (eg, alterations in the gut microbiota, gut-derived metabolites, and gut barrier) may contribute to the onset and progression of extra-intestinal diseases. Previous studies have found that Traditional Chinese Medicine herbs (TCMs) play an important role in manipulating the GME, but a prominent obstacle in current TCM research is the causal relationship between GME and disease amelioration. Encouragingly, co-housing and fecal microbiota transplantation (FMT) provide evidence-based support for TCMs to treat extra-intestinal diseases by targeting GME. In this review, we documented the principles, operational procedures, applications and limitations of the key technologies (ie, co-housing and FMT); furthermore, we provided evidence that TCM works through the GME, especially the gut microbiota (eg, SCFA- and BSH-producing bacteria), the gut-derived metabolites (eg, IS, pCS, and SCFAs), and intestinal barrier to alleviate extra-intestinal diseases. This will be beneficial in constructing microecological pathways for TCM treatment of extra-intestinal diseases in the future.

The molecular insights of bile acid homeostasis in host diseases

Bile acids (BAs) function as detergents promoting nutrient absorption and as hormones regulating nutrient metabolism. Most BAs are key regulatory factors of physiological activities, which are involved in the regulation of glucose, lipid, and drug metabolisms. Hepatic and intestinal diseases have close connections with the systemic cycling disorders of BAs. The abnormal in BA absorption came up with overmuch BAs could be involved in the pathophysiology of liver and bowel and metabolic disorders such as fatty liver diseases and inflammatory bowel diseases. The primary BAs (PBAs), which are synthesized in the liver, can be transformed into the secondary BAs (SBAs) by gut microbiota. The transformation processes are tightly associated with the gut microbiome and the host endogenous metabolism. The BA biosynthesis gene cluster bile-acid-inducible operon is essential for modulating BA pool, gut microbiome composition, and the onset of intestinal inflammation. This forms a bidirectional interaction between the host and its gut symbiotic ecosystem. The subtle changes in the composition and abundance of BAs perturb the host physiological and metabolic activity. Therefore, maintaining the homeostasis of BAs pool contributes to the balance of the body's physiological and metabolic system. Our review aims to dissect the molecular mechanisms underlying the BAs homeostasis, assess the key factors sustaining the homeostasis and the role of BA acting on host diseases. By linking the BAs metabolic disorders and their associated diseases, we illustrate the effects of BAs homeostasis on health and potential clinical interventions can be taken under the latest research findings.

Hyodeoxycholic acid ameliorates nonalcoholic fatty liver disease by inhibiting RAN-mediated PPARα nucleus-cytoplasm shuttling

Nonalcoholic fatty liver disease (NAFLD) is usually characterized with disrupted bile acid (BA) homeostasis. However, the exact role of certain BA in NAFLD is poorly understood. Here we show levels of serum hyodeoxycholic acid (HDCA) decrease in both NAFLD patients and mice, as well as in liver and intestinal contents of NAFLD mice compared to their healthy counterparts. Serum HDCA is also inversely correlated with NAFLD severity. Dietary HDCA supplementation ameliorates diet-induced NAFLD in male wild type mice by activating fatty acid oxidation in hepatic peroxisome proliferator-activated receptor α (PPARα)-dependent way because the anti-NAFLD effect of HDCA is abolished in hepatocyte-specific Pparα knockout mice. Mechanistically, HDCA facilitates nuclear localization of PPARα by directly interacting with RAN protein. This interaction disrupts the formation of RAN/CRM1/PPARα nucleus-cytoplasm shuttling heterotrimer. Our results demonstrate the therapeutic potential of HDCA for NAFLD and provide new insights of BAs on regulating fatty acid metabolism.

Intracellular spatiotemporal metabolism in connection to target engagement

The metabolism in eukaryotic cells is a highly ordered system involving various cellular compartments, which fluctuates based on physiological rhythms. Organelles, as the smallest independent sub-cell unit, are important contributors to cell metabolism and drug metabolism, collectively designated intracellular metabolism. However, disruption of intracellular spatiotemporal metabolism can lead to disease development and progression, as well as drug treatment interference. In this review, we systematically discuss spatiotemporal metabolism in cells and cell subpopulations. In particular, we focused on metabolism compartmentalization and physiological rhythms, including the variation and regulation of metabolic enzymes, metabolic pathways, and metabolites. Additionally, the intricate relationship among intracellular spatiotemporal metabolism, metabolism-related diseases, and drug therapy/toxicity has been discussed. Finally, approaches and strategies for intracellular spatiotemporal metabolism analysis and potential target identification are introduced, along with examples of potential new drug design based on this.

Improving intestinal inflammaging to delay aging? A new perspective

Greying population is becoming an increasingly critical issue for social development. In advanced aging context, organismal multiple tissues and organs experience a progressive deterioration, initially presenting with functional decline, followed by structural disruption and eventually organ failure. The aging of the gut is one of the key links. Decreased gut function leads to reduced nutrient absorption and can perturb systemic metabolic rates. The degeneration of the intestinal structure causes the migration of harmful components such as pathogens and toxins, inducing pathophysiological changes in other organs through the "brain-gut axis" and "liver-gut axis". There is no accepted singular underlying mechanism of aged gut. While the inflamm-aging theory was first proposed in 2000, the mutual promotion of chronic inflammation and aging has attracted much attention. Numerous studies have established that gut microbiome composition, gut immune function, and gut barrier integrity are involved in the formation of inflammaging in the aging gut. Remarkably, inflammaging additionally drives the development of aging-like phenotypes, such as microbiota dysbiosis and impaired intestinal barrier, via a broad array of inflammatory mediators. Here we demonstrate the mechanisms of inflammaging in the gut and explore whether aging-like phenotypes in the gut can be negated by improving gut inflammaging.

Cognitive Alterations in Old Mice Are Associated with Intestinal Barrier Dysfunction and Induced Toll-like Receptor 2 and 4 Signaling in Different Brain Regions

Emerging evidence implicate the 'microbiota-gut-brain axis' in cognitive aging and neuroinflammation; however, underlying mechanisms still remain to be elucidated. Here, we assessed if potential alterations in intestinal barrier function and microbiota composition as well as levels of two key pattern-recognition receptors namely Toll-like receptor (TLR) 2 and TLR4, in blood and different brain regions, and depending signaling cascades are paralleling aging associated alterations of cognition in healthy aging mice. Cognitive function was assessed in the Y-maze and intestinal and brain tissue and blood were collected in young (4 months old) and old (24 months old) male C57BL/6 mice to determine intestinal microbiota composition by Illumina amplicon sequencing, the concentration of TLR2 and TLR4 ligands in plasma and brain tissue as well as to determine markers of intestinal barrier function, senescence and TLR2 and TLR4 signaling. Cognitive function was significantly impaired in old mice. Also, in old mice, intestinal microbiota composition was significantly altered, while the relative abundance of Gram-negative or Gram-positive bacteria in the small and large intestines at different ages was not altered. Moreover, intestinal barrier function was impaired in small intestine of old mice, and the levels of TLR2 and TLR4 ligands were also significantly higher in both portal and peripheral blood. Furthermore, levels of TLR2 and TLR4 ligands, and downstream markers of TLR signaling were higher in the hippocampal and prefrontal cortex of old mice compared to young animals. Taken together, our results suggest that even in 'healthy' aging, cognitive function is impaired in mice going along with an increased intestinal translocation of TLR ligands and alterations of TLR signaling in several brain regions.

Role of the Gut Microbiota and Its Metabolites in Tumorigenesis or Development of Colorectal Cancer

Colorectal cancer (CRC) is the most common cancer of the digestive system with high mortality and morbidity rates. Gut microbiota is found in the intestines, especially the colorectum, and has structured crosstalk interactions with the host that affect several physiological processes. The gut microbiota include CRC-promoting bacterial species, such as Fusobacterium nucleatum, Escherichia coli, and Bacteroides fragilis, and CRC-protecting bacterial species, such as Clostridium butyricum, Streptococcus thermophilus, and Lacticaseibacillus paracasei, which along with other microorganisms, such as viruses and fungi, play critical roles in the development of CRC. Different bacterial features are identified in patients with early-onset CRC, combined with different patterns between fecal and intratumoral microbiota. The gut microbiota may be beneficial in the diagnosis and treatment of CRC; some bacteria may serve as biomarkers while others as regulators of chemotherapy and immunotherapy. Furthermore, metabolites produced by the gut microbiota play essential roles in the crosstalk with CRC cells. Harmful metabolites include some primary bile acids and short-chain fatty acids, whereas others, including ursodeoxycholic acid and butyrate, are beneficial and impede tumor development and progression. This review focuses on the gut microbiota and its metabolites, and their potential roles in the development, diagnosis, and treatment of CRC.

Ginsenoside Rh4 Improves Hepatic Lipid Metabolism and Inflammation in a Model of NAFLD by Targeting the Gut Liver Axis and Modulating the FXR Signaling Pathway

Non-alcoholic fatty liver disease (NAFLD) is a series of disorders of liver metabolism caused by the accumulation of lipids in the liver, which is considered the main cause of hepatocellular carcinoma. Our previous study demonstrated the promising efficacy of ginsenoside Rh4 in improving the intestinal tract and its related metabolites. Meanwhile, many studies in the literature have investigated the gut microbiota and its metabolites, such as bile acids (BAs) and short-chain fatty acids (SCFAs), which play a key role in the pathogenesis of NAFLD. Therefore, this study focused on whether Rh4 could achieve therapeutic effects on NAFLD through the gut-liver axis. The results showed that Rh4 exhibited sound therapeutic effects on the NAFLD model induced by the Western diet and CCl₄ in mice. In the liver, the degrees of hepatic steatosis, lobular inflammation levels, and bile acid in the liver tissue were improved after Rh4 treatment. At the same time, Rh4 treatment significantly increased the levels of intestinal SCFAs and BAs, and these changes were accompanied by the complementary diversity and composition of intestinal flora. In addition, correlation analysis showed that Rh4 affected the expression of proteins involved in the farnesoid X receptor (FXR) signaling pathway in the liver and intestine, which modulates hepatic lipid metabolism, inflammation, and proteins related to bile acid regulation. In conclusion, our study provides a valuable insight into how Rh4 targets the gut-liver axis for the development of NAFLD, which indicates that Rh4 may be a promising candidate for the clinical therapy of NAFLD.

Composition, Diversity and Sex-Related Differences in Intestinal Microbiota in Captive African Penguins (Spheniscus demersus)

An understanding of the microbial communities in African penguins (Spheniscus demersus) could provide valuable information for saving this endangered species. The objective of this study was to investigate the composition, diversity and sex-related differences in the intestinal microbiota of captive African penguins. Fecal samples were collected from 21 captive adult African penguins reared in the same conditions at Shanghai Zoo. The results show that Proteobacteria, Actinobacteria and Firmicutes were the predominant bacteria in the intestinal microbiota of the captive African penguins. No difference was found in microbial diversity between female and male African penguins, as shown by their similar alpha and beta diversities. However, a notable sex-related difference was found between their microbial compositions. Female African penguins have a higher abundance of Pseudomonas and a lower abundance of Kocuria than males. A functional prediction indicates that the "mRNA surveillance pathway", "Polyketide sugar unit biosynthesis", "Wnt signaling pathway", "Lysosome" and "Cell cycle" pathways were significantly enriched in the microbiota of female African penguins. In conclusion, the present study indicates that the compositions and predicted functions of the intestinal microbiota are significantly different between the sexes. Our data suggest that the intestinal microbiota of female African penguins are more unstable than the intestinal microbiota of males in captivity.

16S rRNA gene sequencing reveals the correlation between the gut microbiota and the susceptibility to pathological scars

The gut microbiome profile in patients with pathological scars remains rarely known, especially those patients who are susceptible to pathological scars. Previous studies demonstrated that gut microbial dysbiosis can promote the development of a series of diseases via the interaction between gut microbiota and host. The current study aimed to explore the gut microbiota of patients who are prone to suffer from pathological scars. 35 patients with pathological scars (PS group) and 40 patients with normal scars (NS group) were recruited for collection of fecal samples to sequence the 16S ribosomal RNA (16S rRNA) V3-V4 region of gut microbiota. Alpha diversity of gut microbiota showed a significant difference between NS group and PS group, and beta diversity indicated that the composition of gut microbiota in NS and PS participants was different, which implied that dysbiosis exhibits in patients who are susceptible to pathological scars. Based on phylum, genus, species levels, we demonstrated that the changing in some gut microbiota (Firmicutes; Bacteroides; Escherichia coli, etc.) may contribute to the occurrence or development of pathological scars. Moreover, the interaction network of gut microbiota in NS and PS group clearly revealed the different interaction model of each group. Our study has preliminary confirmed that dysbiosis exhibits in patients who are susceptible to pathological scars, and provide a new insight regarding the role of the gut microbiome in PS development and progression.

Regular Consumption of Cocoa and Red Berries as a Strategy to Improve Cardiovascular Biomarkers via Modulation of Microbiota Metabolism in Healthy Aging Adults

The aim of the present study was to analyze the effects of cocoa flavanols and red berry anthocyanins on cardiovascular biomarkers, such as homocysteine, angiotensin-converting enzyme (ACE), nitric oxide (NO), flow-mediated vasodilation (FMD), blood pressure and lipid profile. Additionally, we aimed to ascertain their possible interactions with microbiota related metabolites, such as secondary bile acids (SBA), short-chain fatty acids (SCFA) and trimethylamine N-oxide (TMAO). A randomized, parallel-group study, single-blind for the research team, was performed on 60 healthy volunteers between the ages of 45 and 85, who consumed 2.5 g/day of cocoa powder (9.59 mg/day of total flavanols), 5 g/day of a red berry mixture (13.9 mg/day of total anthocyanins) or 7.5 g/day of a combination of both for 12 weeks. The group that had consumed cocoa showed a significant reduction in TMAO (p = 0.03) and uric acid (p = 0.01) levels in serum, accompanied by an increase in FMD values (p = 0.03) and total polyphenols. corrected by creatinine (p = 0.03) after the intervention. These latter values negatively correlated with the TMAO concentration (R = -0.57, p = 0.02). Additionally, we observed an increase in carbohydrate fermentation in the groups that had consumed cocoa (p = 0.04) and red berries (p = 0.04) between the beginning and the end of the intervention. This increase in carbohydrate fermentation was correlated with lower levels of TC/HDL ratio (p = 0.01), systolic (p = 0.01) and diastolic blood pressure (p = 0.01). In conclusion, our study showed a positive modulation of microbiota metabolism after a regular intake of cocoa flavanols and red berry anthocyanins that led to an improvement in cardiovascular function, especially in the group that consumed cocoa.

Nanosecond pulse effectively ablated hepatocellular carcinoma with alterations in the gut microbiome and serum metabolites

Background: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death in the world. Nanosecond pulsed electric fields (nsPEFs) have emerged as a new treatment for cancer. This study aims to identify the effectiveness of nsPEFs in the treatment of HCC and analyze the alterations in the gut microbiome and serum metabonomics after ablation. Methods: C57BL/6 mice were randomly divided into three groups: healthy control mice (n = 10), HCC mice (n = 10), and nsPEF-treated HCC mice (n = 23). Hep1-6 cell lines were used to establish the HCC model in situ. Histopathological staining was performed on tumor tissues. The gut microbiome was analyzed by 16S rRNA sequencing. Serum metabolites were analyzed by liquid chromatography-mass spectrometry (LC-MS) metabolomic analysis. Spearman's correlation analysis was carried out to analyze the correlation between the gut microbiome and serum metabonomics. Results: The fluorescence image showed that nsPEFs were significantly effective. Histopathological staining identified nuclear pyknosis and cell necrosis in the nsPEF group. The expression of CD34, PCNA, and VEGF decreased significantly in the nsPEF group. Compared with normal mice, the gut microbiome diversity of HCC mice was increased. Eight genera including Alistipes and Muribaculaceae were enriched in the HCC group. Inversely, these genera decreased in the nsPEF group. LC-MS analysis confirmed that there were significant differences in serum metabolism among the three groups. Correlation analysis showed crucial relationships between the gut microbiome and serum metabolites that are involved in nsPEF ablation of HCC. Conclusion: As a new minimally invasive treatment for tumor ablation, nsPEFs have an excellent ablation effect. The alterations in the gut microbiome and serum metabolites may participate in the prognosis of HCC ablation.

Gut microbiota-mediated secondary bile acid alleviates Staphylococcus aureus-induced mastitis through the TGR5-cAMP-PKA-NF-κB/NLRP3 pathways in mice

Although emerging evidence shows that gut microbiota-mediated metabolic changes regulate intestinal pathogen invasions, little is known about whether and how gut microbiota-mediated metabolites affect pathogen infection in the distal organs. In this study, untargeted metabolomics was performed to identify the metabolic changes in a subacute ruminal acidosis (SARA)-associated mastitis model, a mastitis model with increased susceptibility to Staphylococcus aureus (S. aureus). The results showed that cows with SARA had reduced cholic acid (CA) and deoxycholic acid (DCA) levels compared to healthy cows. Treatment of mice with DCA, but not CA, alleviated S. aureus-induced mastitis by improving inflammation and the blood-milk barrier integrity in mice. DCA inhibited the activation of NF-κB and NLRP3 signatures caused by S. aureus in the mouse mammary epithelial cells, which was involved in the activation of TGR5. DCA-mediated TGR5 activation inhibited the NF-κB and NLRP3 pathways and mastitis caused by S. aureus via activating cAMP and PKA. Moreover, gut-dysbiotic mice had impaired TGR5 activation and aggravated S. aureus-induced mastitis, while restoring TGR5 activation by spore-forming bacteria reversed these changes. Furthermore, supplementation of mice with secondary bile acids producer Clostridium scindens also activated TGR5 and alleviated S. aureus-induced mastitis in mice. These results suggest that impaired secondary bile acid production by gut dysbiosis facilitates the development of S. aureus-induced mastitis and highlight a potential strategy for the intervention of distal infection by regulating gut microbial metabolism.

Gut microbiota and myocardial fibrosis

Myocardial fibrosis (MF) is a pathophysiological condition that accompanies various myocardial diseases and comprises a damaged myocardial matrix repair process. Although fibrosis plays a vital role in repair, it ultimately alters cardiac systolic and diastolic functions. The gut microbiota is a complex and dynamic ecosystem with billions of microorganisms that produce bioactive compounds that influence host health and disease progression. Intestinal microbiota has been shown to correlate with cardiovascular disease, and dysbiosis of the intestinal microbiota is involved in the development of MF. In this review, we discuss the role of intestinal microbiota in the process of MF, including alterations in microbiota composition and the effects of metabolites. We also discuss how diet and medicines can affect cardiac fibrosis by influencing the gut microbiota, and potential future therapies targeting the gut-heart axis. A healthy gut microbiota can prevent disease, but dysbiosis can lead to various symptoms, including the induction of heart disease. In this review, we discuss the relevance of the gut-heart axis and the multiple pathways by which gut microbiota may affect cardiac fibrosis, including inflammatory factors, immune cells, and gut microbiota metabolites, such as trimethylamine-N-oxide (TMAO) and short-chain fatty acids (SCFAs). Finally, we discuss the involvement of gut microbiota in the treatment of cardiac fibrosis, including drugs, fecal microbiota transplantation, and oral probiotics or prebiotics. With future studies on the relationship between the heart and gut microbiota, we hope to find better ways to improve MF through the gut-heart axis.

Sex, puberty, and the gut microbiome

In brief

Sex differences in the gut microbiome may impact multiple aspects of human health and disease. In this study, we review the evidence for microbial sex differences in puberty and adulthood and discuss potential mechanisms driving differentiation of the sex-specific gut microbiome.

Abstract

In humans, the gut microbiome is strongly implicated in numerous sex-specific physiological processes and diseases. Given this, it is important to understand how sex differentiation of the gut microbiome occurs and how these differences contribute to host health and disease. While it is commonly believed that the gut microbiome stabilizes after 3 years of age, our review of the literature found considerable evidence that the gut microbiome continues to mature during and after puberty in a sex-dependent manner. We also review the intriguing, though sparse, literature on potential mechanisms by which host sex may influence the gut microbiome, and vice versa, via sex steroids, bile acids, and the immune system. We conclude that the evidence for the existence of a sex-specific gut microbiome is strong but that there is a dearth of research on how host-microbe interactions lead to this differentiation. Finally, we discuss the types of future studies needed to understand the processes driving the maturation of sex-specific microbial communities and the interplay between gut microbiota, host sex, and human health.

Gut microbiota-derived ursodeoxycholic acid alleviates low birth weight-induced colonic inflammation by enhancing M2 macrophage polarization

BACKGROUND

Low birth weight (LBW) is associated with intestinal inflammation and dysbiosis after birth. However, the underlying mechanism remains largely unknown.

OBJECTIVE

In the present study, we aimed to investigate the metabolism, therapeutic potential, and mechanisms of action of bile acids (BAs) in LBW-induced intestinal inflammation in a piglet model.

METHODS

The fecal microbiome and BA profile between LBW and normal birth weight (NBW) neonatal piglets were compared. Fecal microbiota transplantation (FMT) was employed to further confirm the linkage between microbial BA metabolism and intestinal inflammation. The therapeutic potential of ursodeoxycholic acid (UDCA), a highly differentially abundant BA between LBW and NBW piglets, in alleviating colonic inflammation was evaluated in both LBW piglets, an LBW-FMT mice model, and a DSS-induced colitis mouse model. The underlying cellular and molecular mechanisms by which UDCA suppresses intestinal inflammation were also investigated in both DSS-treated mice and a macrophage cell line. Microbiomes were analyzed by using 16S ribosomal RNA sequencing. Fecal and intestinal BA profiles were measured by using targeted BA metabolomics. Levels of farnesoid X receptor (FXR) were knocked down in J774A.1 cells with small interfering RNAs.

RESULTS

We show a significant difference in both the fecal microbiome and BA profiles between LBW and normal birth weight animals in a piglet model. Transplantation of the microbiota of LBW piglets to antibiotic-treated mice leads to intestinal inflammation. Importantly, oral administration of UDCA, a major BA diminished in the intestinal tract of LBW piglets, markedly alleviates intestinal inflammation in LBW piglets, an LBW-FMT mice model, and a mouse model of colitis by inducing M2 macrophage polarization. Mechanistically, UDCA reduces inflammatory cytokine production by engaging BA receptor FXR while suppressing NF-κB activation in macrophages.

CONCLUSIONS

These findings establish a causal relationship between LBW-associated intestinal abnormalities and dysbiosis, suggesting that restoring intestinal health and postnatal maldevelopment of LBW infants may be achieved by targeting intestinal microbiota and BA metabolism. Video Abstract.

Effects of electroacupuncture on urinary metabolome and microbiota in presenilin1/2 conditional double knockout mice

Aim

The treatment of Alzheimer's disease (AD) is still a worldwide problem due to the unclear pathogenesis and lack of effective therapeutic targets. In recent years, metabolomic and gut microbiome changes in patients with AD have received increasing attention, and the microbiome-gut-brain (MGB) axis has been proposed as a new hypothesis for its etiology. Considering that electroacupuncture (EA) efficiently moderates cognitive deficits in AD and its mechanisms remain poorly understood, especially regarding its effects on the gut microbiota, we performed urinary metabolomic and microbial community profiling on EA-treated AD model mice, presenilin 1/2 conditional double knockout (PS cDKO) mice, to observe the effect of EA treatment on the gut microbiota in AD and find the connection between affected gut microbiota and metabolites.

Materials and methods

After 30 days of EA treatment, the recognition memory ability of PS cDKO mice was evaluated by the Y maze and the novel object recognition task. Urinary metabolomic profiling was conducted with the untargeted GC-MS method, and 16S rRNA sequence analysis was applied to analyze the microbial community. In addition, the association between differential urinary metabolites and gut microbiota was clarified by Spearman's correlation coefficient analysis.

Key findings

In addition to reversed cognitive deficits, the urinary metabolome and gut microbiota of PS cDKO mice were altered as a result of EA treatment. Notably, the increased level of isovalerylglycine and the decreased levels of glycine and threonic acid in the urine of PS cDKO mice were reversed by EA treatment, which is involved in glyoxylate and dicarboxylate metabolism, as well as glycine, serine, and threonine metabolism. In addition to significantly enhancing the diversity and richness of the microbial community, EA treatment significantly increased the abundance of the genus Mucispirillum, while displaying no remarkable effect on the other major altered gut microbiota in PS cDKO mice, norank_f_Muribaculaceae, Lactobacillus, and Lachnospiraceae_NK4A136 group. There was a significant correlation between differential urinary metabolites and differential gut microbiota.

Significance

Electroacupuncture alleviates cognitive deficits in AD by modulating gut microbiota and metabolites. Mucispirillum might play an important role in the underlying mechanism of EA treatment. Our study provides a reference for future treatment of AD from the MGB axis.

Sex-Mediated Differences in TNF Signaling- and ECM-Related Gene Expression in Aged Rat Kidney

Aging leads to the functional decline of an organism, which is associated with age and sex. To understand the functional change of kidneys depending on age and sex, we carried out a transcriptome analysis using RNA sequencing (RNA-Seq) data from rat kidneys. Four differentially expressed gene (DEG) sets were generated according to age and sex, and Gene Ontology analysis and overlapping analysis of Kyoto Encyclopedia of Genes and Genomes pathways were performed for the DEG sets. Through the analysis, we revealed that inflammation- and extracellular matrix (ECM)-related genes and pathways were upregulated in both males and females during aging, which was more prominent in old males than in old females. Furthermore, quantitative real-time PCR analysis confirmed that the expression of tumor necrosis factor (TNF) signaling-related genes, Birc3, Socs3, and Tnfrsf1b, and ECM-related genes, Cd44, Col3a1, and Col5a2, which showed that the genes were markedly upregulated in males and not females during aging. Also, hematoxylin-eosin (H&E) staining for histological analysis showed that renal damage was highly shown in old males rather than old females. In conclusion, in the rat kidney, the genes involved in TNF signaling and ECM accumulation are upregulated in males more than in females during aging. These results suggest that the upregulation of the genes may have a higher contribution to age-related kidney inflammation and fibrosis in males than in females.

Divergent impacts on the gut microbiome and host metabolism induced by traditional Chinese Medicine with Cold or Hot properties in mice

BACKGROUND

Traditional Chinese Medicine (TCM) has been practiced and developed in China over thousands of years under the guidance of a series of complicated traditional theories. Herbs within TCM usually are classified according to their different properties ranging from cold, cool, warm to hot, which are simplified as Cold and Hot properties. TCM with either Cold or Hot properties are used in various formulae designed for the purpose of restoring the balance of patients. Emerging evidence has highlighted that an altered gut microbiota or host metabolism are critically involved in affecting the healing properties of TCM. However, at present the exact influences and crosstalk on the gut microbiota and host metabolism remain poorly understood.

METHODS

In the present study, the divergent impacts of six TCMs with either Cold or Hot properties on gut microbiome and host metabolism during short- or long-term intervention in mice were investigated. Six typical TCMs with Hot or Cold properties including Cinnamomi Cortex (rougui, RG), Zingiberis Rhizoma (ganjiang, GJ), Aconiti Lateralis Radix Praeparata (fuzi, FZ), Rhei Radix et Rhizoma (dahuang, DH), Scutellariae Radix (huangqin, HQ), and Copitdis Rhizoma (huanglian, HL) were selected and orally administered to male C57BL/6J mice for a short- or a long-term (7 or 35 days). At the end of experiments, serum and cecal contents were collected for metabolomic and gut microbiome analyses using gas chromatography-tandem mass spectrometry (GC-MS) or 16S ribosomal deoxyribonucleic acid (16S rDNA) sequencing.

RESULTS

The results revealed that the gut microbiome underwent divergent changes both in its composition and functions after short-term intervention with TCM possessing either Cold or Hot properties. Interestingly, the number of changed genus and bacteria pathways was reduced in Hot_LT, but was increased in Cold_LT, especially in the HL group. Increased α diversity and a reduced F/B ratio revealed the changes in Hot_ST, but a reduced Shannon index and increased altered bacteria function was evident in Cold_LT. The serum metabolic profile showed that the influence of TCM on host metabolism was gradually reduced over time. Glycolipid metabolism related pathways were specifically regulated by Hot_ST, but also surprisingly by Cold_LT. Reduced lactic acid in Cold_ST, increased tryptophan concentrations and decreased proline and threonine concentrations in Cold_LT perhaps highlighting the difference between the two natures influence on serum metabolism. These metabolites were closely correlated with altered gut microbiota shown by further correlation analyses.

CONCLUSION

The results indicated that TCM properties could be, at least partially characterized by an alteration in the gut microbiota and metabolic profile, implying that the divergent responses of gut microbiome and host metabolism are involved in different responses to TCM.

Alginate Alleviates Dextran Sulfate Sodium-Induced Colitis by Promoting Bifidobacterium animalis and Intestinal Hyodeoxycholic Acid Synthesis in Mice

Alginate (ALG) is known to alleviate intestinal inflammation in inflammatory bowel disease, but its mechanism of action remains elusive. In the present study, we studied the involvement of the intestinal microbiota and bile acid (BA) metabolism in ALG-mediated anti-inflammatory effects in mice. A combination of 16S rRNA gene amplicon sequencing, shotgun metagenomic sequencing, and targeted BA metabolomic profiling was employed to investigate structural and functional differences in the colonic microbiota and BA metabolism in dextran sulfate sodium (DSS)-treated mice with or without dietary supplementation of ALG. We further explored the role of the intestinal microbiota as well as a selected ALG-enriched bacterium and BA in DSS-induced colitis. Dietary ALG alleviated DSS-mediated intestinal inflammation and enriched a small set of bacteria including Bifidobacterium animalis in the colon (P < 0.05). Additionally, ALG restored several bacteria carrying secondary BA-synthesizing enzymes such as 7α-hydroxysteroid dehydrogenase and BA hydrolase to healthy levels in DSS-treated mice. Although a majority of BAs were suppressed by DSS, a few secondary BAs such as hyodeoxycholic acid (HDCA) were markedly enriched by ALG. Furthermore, ALG significantly upregulated the expression of a major BA receptor, the farnesoid X receptor, while suppressing NF-κB and c-Jun N-terminal kinase (JNK) activation. Depletion of the intestinal microbiota completely abrogated the protective effect of ALG in DSS-treated mice. Similar to ALG, B. animalis and HDCA exerted a strong anti-inflammatory effect in DSS-induced colitis by downregulating inflammatory cytokines (interleukin-1β [IL-1β], IL-6, and tumor necrosis factor alpha [TNF-α]). Taken together, these results indicated that ALG achieves its alleviating effect on intestinal inflammation through regulation of the microbiota by enriching B. animalis to promote the biosynthesis of specific secondary BAs such as HDCA. These findings have revealed intricate interactions among the intestinal microbiota, BA metabolism, and intestinal health and further provided a novel strategy to improve intestinal health through targeted manipulation of the intestinal microbiota and BA metabolism. IMPORTANCE ALG has been shown to ameliorate inflammatory bowel disease (IBD), but little is known about the mechanism of its anti-inflammatory action. This study was the first to demonstrate that ALG provided a preventive effect against colitis in an intestinal microbiota-dependent manner. Furthermore, we confirmed that by selectively enriching intestinal B. animalis and secondary BA (HDCA), ALG contributed to the attenuation of DSS-induced colitis. These findings contribute to a better understanding of the mechanism of action of ALG on the attenuation of colitis and provide new approaches to IBD therapy by regulating gut microbial BA metabolism.

Association between maternal antibiotic exposure during pregnancy and childhood obesity in the Japan Environment and Children's Study

BACKGROUND

The association between maternal antibiotic exposure during pregnancy and childhood obesity is still unclear.

OBJECTIVES

The study aimed to evaluate the association between prenatal exposure to antibiotics and obesity at age 3 years using data from a large Japanese birth cohort.

METHODS

The Japan Environment and Children's Study is a nationwide birth cohort study. In this study, singleton vaginal full-term births were included. Obesity was defined as body mass index ≥95th percentile according to child growth standards. Prenatal antibiotic exposure was defined as antimicrobial agent use during pregnancy and was collected from maternal interviews and medical record transcripts. Logistic regression analysis was performed to evaluate the association of prenatal antibiotic exposure with child obesity at 3 years.

RESULTS

In the crude and adjusted models with all children, maternal antibiotic exposure during pregnancy showed a marginal relationship with child obesity at 3 years. In the analyses according to exposure period and sex, exposure to antibiotics during the second/third trimester was significantly associated with obesity at the age of 3 years in female infants, but not in male infants, although the exposure during the first trimester was not in both sexes.

CONCLUSION

Maternal antibiotic exposure during mid/late pregnancy may result in child obesity.

Gut microbiome and metabolome analyses reveal the protective effect of special high-docosahexaenoic acid tuna oil on d-galactose-induced aging in mice

Aging is closely related to altered gut function and its microbiome composition. To elucidate the mechanisms involved in the preventive effect of special high-docosahexaenoic acid tuna oil (HDTO) on senescence, the effects of different doses of HDTO on the gut microbiome and metabolome of d-galactose-induced aging mice were studied. Deferribacteres and Tenericutes and uridine might be used as indicator bacteria and characteristic metabolites to identify aging, respectively. HDTO markedly improved the impaired memory and antioxidant abilities induced by d-galactose. At the phylum level, the abundance of Firmicutes and Tenericutes was significantly increased upon d-galactose induction, while that of Bacteroidetes, Proteobacteria, and Deferribacteres was significantly decreased. At the genus level, the variation mainly presented as an increase in the abundance of the Firmicutes genera Ligilactobacillus, Lactobacillus, and Erysipelothrix, the decrease in the abundance of the Bacteroidetes genera Bacteroides and Alistipes, the Firmicutes genus Dielma, and the Deferribacteres genus Mucispirillum. HDTO supplementation reversed the alterations in the intestinal flora by promoting the proliferation of beneficial flora during the aging process; the metabolic pathways, such as glycine-serine-threonine metabolism, valine-leucine-isoleucine biosynthesis, and some metabolic pathways involved in uridine, were also partially restored. Furthermore, the correlation analysis illustrated an obvious correlation between gut microbiota, its metabolites, and aging-related indices. Moreover, it is worth noting that the metabolic regulation by dietary intervention varied with different HDTO doses and did not present a simple additive effect; indeed, each dose showed a unique modulation mechanism.

Different gender-derived gut microbiota influence stroke outcomes by mitigating inflammation

Background and purpose

Stroke is associated with high disability and mortality rates and increases the incidence of organ-related complications. Research has revealed that the outcomes and prognosis of stroke are regulated by the state of the intestinal microbiota. However, the possibility that the manipulation of the intestinal microbiota can alter sex-related stroke outcomes remain unknown.

Methods

To verify the different effects of microbiota from different sexes on stroke outcomes, we performed mouse fecal microbiota transplantation (FMT) and established a model of ischemic stroke. Male and female mice received either male or female microbiota through FMT. Ischemic stroke was triggered by MCAO (middle cerebral artery occlusion), and sham surgery served as a control. Over the next few weeks, the mice underwent neurological evaluation and metabolite and inflammatory level detection, and we collected fecal samples for 16S ribosomal RNA analysis.

Results

We found that when the female mice were not treated with FMT, the microbiota (especially the Firmicutes-to-Bacteroidetes ratio) and the levels of three main metabolites tended to resemble those of male mice after experimental stroke, indicating that stroke can induce an ecological imbalance in the biological community. Through intragastric administration, the gut microbiota of male and female mice was altered to resemble that of the other sex. In general, in female mice after MCAO, the survival rate was increased, the infarct area was reduced, behavioral test performance was improved, the release of beneficial metabolites was promoted and the level of inflammation was mitigated. In contrast, mice that received male microbiota were much more hampered in terms of protection against brain damage and the recovery of neurological function.

Conclusion

A female-like biological community reduces the level of systemic proinflammatory cytokines after ischemic stroke. Poor stroke outcomes can be positively modulated following supplementation with female gut microbiota.

Regular fecal microbiota transplantation to Senescence Accelerated Mouse-Prone 8 (SAMP8) mice delayed the aging of locomotor and exploration ability by rejuvenating the gut microbiota

Recent evidence points out the role of the gut microbiota in the aging process. However, the specific changes and relevant interventions remain unclear. In this study, Senescence Accelerated Mouse-Prone 8 (SAMP8) mice were divided into four groups; young-FMT-group transplanted fecal microbiota from young donors (2–3°months old) and old-FMT-group transplanted from old donors (10–11°months old); additionally, other two groups either adult mice injected with saline solution or untreated mice served as the saline and blank control groups, respectively. All mice were intervened from their 7-months-old until 13-months-old. The open field test at 9 and 11°months of age showed that the mice transplanted with gut microbiota from young donors had significantly better locomotor and exploration ability than those of transplanted with old-donors gut microbiota and those of saline control while was comparable with the blank control. 16S rRNA gene sequencing showed that the gut microbiome of recipient mice of young donors was altered at 11°months of age, whereas the alternation of the gut microbiome of old-donor recipient mice was at 9°months. For comparison, the recipient mice in the blank and saline control groups exhibited changes in the gut microbiome at 10°months of age. The hallmark of aging-related gut microbiome change was an increase in the relative abundance of Akkermansia, which was significantly higher in the recipients transplanted with feces from older donors than younger donors at 9°months of age. This study shows that fecal microbiota transplantation from younger donors can delay aging-related declines in locomotor and exploration ability in mice by changing the gut microbiome.

Melatonin relieves hepatic lipid dysmetabolism caused by aging via modifying the secondary bile acid pattern of gut microbes

It has been reported that aging-generated gut microecosystem may promote host hepatic lipid dysmetabolism through shaping the pattern of secondary bile acids (BAs). Then as an oral drug, melatonin (Mel)-mediated beneficial efforts on the communication between gut microbiota and aging host are still not clearly. Here, we show that aging significantly shapes the pattern of gut microbiota and BAs, whereas Mel treatment reverses these phenotypes (P < 0.05), which is identified to depend on the existence of gut microbiota. Mechanistically, aging-triggered high-level expression of ileac farnesoid X receptor (FXR) is significantly decreased through Mel-mediated inhibition on Campylobacter jejuni (C. jejuni)-induced deconjugation of tauroursodeoxycholic acid (TUDCA) and glycoursodeoxycholic acid (GUDCA) (P < 0.05). The aging-induced high-level of serum taurine chenodeoxycholic acid (TCDCA) activate trimethylamine-N-oxide (TMAO)-triggered activating transcriptional factor 4 (ATF4) signaling via hepatic FXR, which further regulates hepatic BAs metabolism, whereas TUDCA inhibits aging-triggered high-level of hepatic ATF4. Overall, Mel reduces C. jejuni-mediated deconjugation of TUDCA to inhibit aging-triggered high-level expression of hepatic FXR, which further decreases hepatic TMAO production, to relieve hepatic lipid dysmetabolism.

Gender-related differences in the effects of Inonotus obliquus polysaccharide on intestinal microorganisms in SD rats model

Natural edible fungal polysaccharides are of research and application value for the prevention of diseases by improving the microenvironment within the intestine. Inonotus obliquus polysaccharide (IOP) extracts have strong antioxidant, anti-inflammatory, and other biological activities, and as such, it could be used as prebiotics to improve the viability of intestinal microbes, maintain intestinal homeostasis and improve intestinal immunity. The effects of sex on intestinal microbiota after IOP absorption was determined. In this study, IOP had different effects on the intestinal flora of male and female rats, with the diversity and richness showing opposite changes. At the same time, after IOP intervention, changes in the dominant intestinal flora of female rats was less compared with that of males. In addition, while Clostridia, Lactobacillus and Roseburia were the dominant intestinal microbes in female rats, males had mainly Bacteroidota from different families and genera, along with an increasing proportion of Muribaculaceae from different families and genera. IOP could further regulate the intestinal microenvironment of male and female SD rats by enhancing the vitality of their dominant microorganisms, and for both sexes, this enabled the screening of dominant microflora that were conducive to the balance of the intestinal flora. These results help to understand the effects of sex-related differences on the composition of the intestinal microbiota as well as on diseases.

Lactoferrin Prevents Chronic Alcoholic Injury by Regulating Redox Balance and Lipid Metabolism in Female C57BL/6J Mice

This study aimed to investigate the preventive effects of lactoferrin (Lf) on chronic alcoholic liver injury (ALI) in female mice. Female C57BL/6J mice were randomly divided into four groups: control group (CON), ethanol administration group (EtOH), low-dose Lf treatment group (LLf), and high-dose Lf group (HLf). In the last three groups, chronic ALI was induced by administering 20% ethanol ad libitum for 12 weeks. Mice in the CON and EtOH groups were fed with AIN-93G diet. Meanwhile, 0.4% and 4% casein in the AIN-93G diet were replaced by Lf as the diets of LLf and HLf groups, respectively. HLf significantly reduced hepatic triglyceride content and improved pathological morphology. HLf could inhibit cytochrome P450 2E1 overexpression and promote alcohol dehydrogenase-1 expression. HLf activated protein kinase B and AMP-activated protein kinase (AMPK), as well as upregulating nuclear-factor-erythroid-2-related factor-2 expression to elevate hepatic antioxidative enzyme activities. AMPK activation also benefited hepatic lipid metabolism. Meanwhile, HLf had no obvious beneficial effects on gut microbiota. In summary, Lf could alleviate chronic ALI in female mice, which was associated with redox balance and lipid metabolism regulation.

Comparison of bile acids profiles in the enterohepatic circulation system of mice and rats

Bile acids (BAs) were selected as biomarkers for the diagnosis and prevention of multiple liver diseases, and they were also considered as an important signal transductor via "liver-gut" axis. As important factors for maintaining the normal function and tissue morphology, BA homeostasis throughout the enterohepatic circulation system was guaranteed by BA synthases and transporters, nuclear receptors (NRs) and gut microbiota, all of which presented significant species differences. Thus, we simultaneously quantify BA profiles in the enterohepatic circulation of SD rats and C57BL/6 mice to reveal the species differences of BA homeostasis between these two main rodents of preclinical studies. Our results showed that BA profiles of mice plasma, bile and liver were most dissimilar from these of rats. Meanwhile, BAs profiles also presented obvious species differences in the intestine of mice and rats, especially small intestine. Unlike rats, taurine-conjugated bile acids (T-BAs) were predominant in mice small intestine content and tissue, in which taurocholic acid (TCA) was the most prominent BAs. BAs dynamic analysis showed that compared with rats, mice showed stranger taurine and glycine de-conjugations in lager intestine. However, both the ratios of unconjugated bile acids (Un-BAs) to conjugated BAs, and secondary BAs to primary BAs in mice small content and tissue were all much lower than these in rats. Furthermore, ileum BAs profiles also showed significantly separation trend between rats and mice, whether content or tissue. Our data revealed that the patterns of BAs homeostasis in mice enterohepatic circulation system were significantly different from these in rats (especially in intestine), suggesting that more cautious should be paid to the selection of BAs as biomarkers for disease diagnosis or/and drug induced toxicity, and the certain role and mechanism of individual BA in the pathological process of BA-related diseases via "liver-gut" axis should be verified by using of multiple species.

Comprehensive 16S rRNA and metagenomic data from the gut microbiome of aging and rejuvenation mouse models

The gut microbiota is associated with the health and longevity of the host. A few methods, such as fecal microbiota transplantation and oral administration of probiotics, have been applied to alter the gut microbiome and promote healthy aging. The changes in host microbiomes still remain poorly understood. Here, we characterized both the changes in gut microbial communities and their functional potential derived from colon samples in mouse models during aging. We achieved this through four procedures including co-housing, serum injection, parabiosis, and oral administration of Akkermansia muciniphila as probiotics using bacterial 16 S rRNA sequencing and shotgun metagenomic sequencing. The dataset comprised 16 S rRNA sequencing (36,249,200 paired-end reads, 107 sequencing data) and metagenomic sequencing data (307,194,369 paired-end reads, 109 sequencing data), characterizing the taxonomy of bacterial communities and their functional potential during aging and rejuvenation. The generated data expand the resources of the gut microbiome related to aging and rejuvenation and provide a useful dataset for research on developing therapeutic strategies to achieve healthy active aging.

Dietary nutrients mediate crosstalk between bile acids and gut microbes in animal host metabolism

Bile acids (BAs) are synthesized by liver, then gut microbes embellish primary BAs into secondary BAs with diverse and biological functions. Over the past few decades, amounts of evidences demonstrated the importance of gut microbes in BA metabolism. There is also significant evidence that BAs are regarded as cell signals in gut-liver, gut-brain, and gut-testis axis. Moreover, the interaction between BAs and gut microbes plays a key role not only in the absorption and metabolism of nutrients, but the regulation of immune function. Herein, we collected the major information of the BA metabolism-related bacteria, nutrients, and cell signals, focused on the possible molecular mechanisms by "Microbes-Bile acids" crosstalk, highlighted the gut-liver, gut-brain, and gut-testis axis, and discussed the possibility and application of the regulation of BA metabolism by nutrients.

Fecal microbiota transfer between young and aged mice reverses hallmarks of the aging gut, eye, and brain

BACKGROUND

Altered intestinal microbiota composition in later life is associated with inflammaging, declining tissue function, and increased susceptibility to age-associated chronic diseases, including neurodegenerative dementias. Here, we tested the hypothesis that manipulating the intestinal microbiota influences the development of major comorbidities associated with aging and, in particular, inflammation affecting the brain and retina.

METHODS

Using fecal microbiota transplantation, we exchanged the intestinal microbiota of young (3 months), old (18 months), and aged (24 months) mice. Whole metagenomic shotgun sequencing and metabolomics were used to develop a custom analysis workflow, to analyze the changes in gut microbiota composition and metabolic potential. Effects of age and microbiota transfer on the gut barrier, retina, and brain were assessed using protein assays, immunohistology, and behavioral testing.

RESULTS

We show that microbiota composition profiles and key species enriched in young or aged mice are successfully transferred by FMT between young and aged mice and that FMT modulates resulting metabolic pathway profiles. The transfer of aged donor microbiota into young mice accelerates age-associated central nervous system (CNS) inflammation, retinal inflammation, and cytokine signaling and promotes loss of key functional protein in the eye, effects which are coincident with increased intestinal barrier permeability. Conversely, these detrimental effects can be reversed by the transfer of young donor microbiota.

CONCLUSIONS

These findings demonstrate that the aging gut microbiota drives detrimental changes in the gut-brain and gut-retina axes suggesting that microbial modulation may be of therapeutic benefit in preventing inflammation-related tissue decline in later life. Video abstract.

Age-dependent effects of a high-fat diet combined with dietary advanced glycation end products on cognitive function and protection with voluntary exercise

To determine whether a high fat diet (HFD) combined with an advanced glycation end products (AGEs) diet will induce worse cognitive impairment than a HFD alone and to investigate whether voluntary exercise is capable of improving cognitive function after the combined diet, young and middle-aged male C57BL/6J mice were randomly assigned to four groups, i.e., control, HFD, combined diet, and combined diet treated with voluntary exercise. Compared to HFD, combined diet induced worse memory abilities only in middle-aged mice, as exhibited by the reduced number of crossings and reduced distance in the target zone during a probe trial. Exercise reversed combined-diet-induced cognitive impairment for both ages of mice. For young mice, the neuro-protective effects of exercise were mainly associated with inhibition of NLRP3, Dnmt3a, Dnmt3b, and H3K9me2 and elevation of OST48; it also elevated Bacilli and reduced Epsilonproteobacteria, Campylobacterales, and Helicobacter. For middle-aged mice, exercise elevated Tet2, inhibited NF-κB and NLRP3, and rebalanced circadian clock proteins and the RAGE-OST48 axis; also, exercise elevated Coriobacteriia/Coriobacteriaceae, Erysipelotrichaceae, and Allobaculum and restored intestinal permeability.