Indole-3-propionic Acid Research Articles

Early Metabolomic Profiling as a Predictor of Renal Function Six Months After Kidney Transplantation

Background: Kidney transplantation is the therapy of choice for patients with advanced chronic kidney disease; however, predicting graft outcomes remains a significant challenge. Early identification of reliable biomarkers could enhance post-transplant management and improve long-term outcomes. This study aimed to identify metabolomic biomarkers within the first week after kidney transplantation that predict renal function at six months. Methods: We conducted a prospective study involving 50 adult patients who received deceased donor kidney transplants. Plasma samples collected one week after transplant were analyzed using liquid chromatography–mass spectrometry in a semi-targeted metabolomic approach. A Partial Least Squares-Discriminant Analysis (PLS-DA) model identified metabolites associated with serum creatinine > 1.5 mg/dL at six months. Metabolites were selected based on a Variable Importance in Projection (VIP) score > 1.5, which was used to optimize model performance. Results: The PLS-DA model demonstrated strong predictive performance with an area under the curve (AUC) of 0.958. The metabolites negatively associated with serum creatinine > 1.5 mg/dL were 3-methylindole, guaiacol, histidine, 3-indolepropionic acid, and α-lipoic acid. Conversely, the metabolites positively associated with worse kidney graft outcomes included homocarnosine, 5-methylcytosine, xanthosine, choline, phenylalanine, kynurenic acid, and L-kynurenine. Conclusions: Early metabolomic profiling after transplantation shows promise in predicting renal function. Identifying metabolites with antioxidant and anti-inflammatory properties, as well as those that are harmful and could be targeted therapeutically, underscores their potential clinical significance. The link between several metabolites and the tryptophan pathway suggests that further specific evaluation of this pathway is warranted. These biomarkers can enhance patient management and graft survival.

Indole Propionic Acid (IPA), A Gut Microbiota-Derived Metabolite, in Active Pulmonary Tuberculosis (TB) Infection: A Case Control Study

Introduction: A metabolomics study revealed that the tryptophan (Trp) pathway is upregulated in tuberculosis (TB) infection. Indole propionic acid (IPA) is a gut microbiota-derived tryptophan metabolite with antimycobacterial properties through TrpE inhibition and as ligand for AhR in in vitro and in vivo studies. TB infection is associated with gut dysbiosis. However, plasma IPA levels and related factors in active TB patients have not yet been explored. This study aimed to determine the differences and correlations between plasma IPA levels and patient characteristics (age, gender, BMI and GeneXpert result), IPA-producing gut microbiota (Clostridium sporogenes, Lactobacillus sp., and Peptostreptococcus anaerobius), and IFN-γ concentrations in active TB patients and healthy subjects. Materials and methods: A case-control study was performed in 29 active TB patients and 30 healthy controls (HCs) in Aceh, Indonesia. The plasma IPA and IFN-γ levels were measured by ELISA, and the relative abundance of gut microbiota was determined by quantitative PCR (qPCR). The results and discussion: Increased plasma IPA levels (median (IQR) of 22.2 pmol/L (21.3 - 23.9) vs. 18.9 pmol/L (17 - 22.8), p 0.000) were associated with active TB according to the adjusted model (AOR 1.36 (95 % CI 0.37 - 5.1)). Increase of plasma IPA level in higher mycobacterial load patients was found. Higher plasma IPA was positively associated with female, normo- and overweight status, and higher relative abundance of C. sporogenes. The metabolite could be used to discriminate active TB disease at a cutoff of 21.40 pmol/L (72 % sensitivity, 70 % specificity and AUC 0.77). Dysbiosis in IPA-producing bacteria was showed in active TB patients. Conclusion: Plasma IPA could be considered as TB biomarker, and it may also influence disease progression. Future works are needed to validate plasma IPA as biomarker in LTBI and other respiratory infection, as well as its role as biomarker of treatment monitoring response. HIGHLIGHTS The upregulation of the tryptophan (Trp) pathway in tuberculosis infection. Indole propionic acid (IPA) is a Trp metabolite with antimycobacterial properties Higher plasma IPA levels were found in TB patients than in healthy subjects. Dysbiosis of several IPA-producing gut microbiota was revealed in this study. GRAPHICAL ABSTRACT

Clostridium sporogenes-derived metabolites protect mice against colonic inflammation

ABSTRACT Gut microbiota-derived metabolites play a pivotal role in the maintenance of intestinal immune homeostasis. Here, we demonstrate that the human commensal Clostridium sporogenes possesses a specific metabolic fingerprint, consisting predominantly of the tryptophan catabolite indole-3-propionic acid (IPA), the branched-chain acids (BCFAs) isobutyrate and isovalerate and the short-chain fatty acids (SCFAs) acetate and propionate. Mono-colonization of germ-free mice with C. sporogenes (CS mice) affected colonic mucosal immune cell phenotypes, including up-regulation of Il22 gene expression, and increased abundance of transcriptionally active colonic tuft cells and Foxp3+ regulatory T cells (Tregs). In DSS-induced colitis, conventional mice suffered severe inflammation accompanied by loss of colonic crypts. These symptoms were absent in CS mice. In conventional, but not CS mice, bulk RNAseq analysis of the colon revealed an increase in inflammatory and Th17-related gene signatures. C. sporogenes-derived IPA reduced IL-17A protein expression by suppressing mTOR activity and by altering ribosome-related pathways in Th17 cells. Additionally, BCFAs and SCFAs generated by C. sporogenes enhanced the activity of Tregs and increased the production of IL-22, which led to protection from colitis. Collectively, we identified C. sporogenes as a therapeutically relevant probiotic bacterium that might be employed in patients with inflammatory bowel disease (IBD).

Maternal Diet during Pregnancy Alters the Metabolites in Relation to Metabolic and Neurodegenerative Diseases in Young Adult Offspring

Maternal nutrition during the critical period of pregnancy increases the susceptibility of offspring to the development of diseases later in life. This study aimed to analyze metabolite profiles to investigate the effect of maternal diet during pregnancy on changes in offspring plasma metabolites and to identify correlations with metabolic parameters. Pregnant Sprague-Dawley rats were exposed to under- and overnutrition compared to controls, and their offspring were fed a standard diet after birth. Plasma metabolism was profiled in offspring at 16 weeks of age using liquid chromatography–mass spectrometry (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS). We analyzed 80 metabolites to identify distinct metabolites and metabolic and neurodegenerative disease-associated metabolites that were sex-differentially altered in each group compared to controls (p < 0.05, VIP score > 1.0). Specifically, changes in 3-indolepropionic acid, anthranilic acid, linoleic acid, and arachidonic acid, which are involved in tryptophan and linoleic acid metabolism, were observed in male offspring and correlated with plasma leptin levels in male offspring. Our results suggest that fatty acids involved in tryptophan and linoleic acid metabolism, which are altered by the maternal diet during pregnancy, may lead to an increased risk of metabolic and neurodegenerative diseases in the early life of male offspring.

12440 Exploring The Potential Protective Role Of The Bacterial-derived Metabolite Indole-3-propionic Acid Against Obesogenic Insults In Placenta Cell Lines

Abstract Disclosure: J. Ernst: None. L. Conlon: None. R. Gupta: None. L. Kang: None. M.E. Heard-Lipsmeyer: None. Obesity during pregnancy is associated with detrimental changes in placental function that lead to the development of complications such as gestational diabetes and preeclampsia as well as altered metabolism in the offspring. With the incidence of obesity reaching epidemic levels world-wide, it is imperative to find mechanisms to mitigate these risks during pregnancy. The gut-microbiome is a diverse system that regulates numerous body functions through the secretion of specific metabolites. Gut dysbiosis has recently emerged as one mechanism that contributes to placental dysfunction and clear associations between obesity and gut dysbiosis are evident. Indole-3-propionic acid (IPA) is a gut microbiome-derived metabolite that has anti-inflammatory, anti-oxidative stress and glucose regulatory functions, all of which are dysregulated in obesity. Previous studies have found diminished levels of IPA in serum of women with overweight/obesity. However, it remains unknown what the physiological functions of IPA are in the placenta and if it could have potential protective effects against perturbations caused by obesity. The objective of this study is to determine what physiological role IPA plays in the placenta and if IPA can protect against obesogenic insults that contribute to placental pathology. For this study, we developed an in vitro model of obesity where two human placental cell lines, BeWo (choriocarcinoma) and HTR8 (normal immortalized trophoblasts) were cultured in media conditioned by mature human adipocytes (ACM). RNA sequencing (RNAseq) analysis was used to determine acute effects of IPA treatment after 24 hours in the presence and absence of ACM. We further examined the influence of IPA on insulin signaling with physiological and hyperinsulinemia levels of insulin at 24 and 72 hours utilizing QPCR and western blot analyses. RNAseq analysis revealed treatment with physiological levels of IPA induced changes in genes associated with normal placental function, autophagy and inflammatory mediated processes and other pathways. Our RNAseq analysis offers initial insight into the molecular mechanisms of IPA in placental cells. Future analyses will investigate the potential role of insulin signaling, glucose homeostasis and oxidative stress. Collectively, this study highlights the importance of a healthy gut microbiome and potentially serves as a window of opportunity to mitigate the onset or severity of pregnancy-related disorders such as gestational diabetes by enhancing the gut microbiome prior to pregnancy. Presentation: 6/1/2024

12440 Exploring The Potential Protective Role Of The Bacterial-derived Metabolite Indole-3-propionic Acid Against Obesogenic Insults In Placenta Cell Lines

Abstract Disclosure: J. Ernst: None. L. Conlon: None. R. Gupta: None. L. Kang: None. M.E. Heard-Lipsmeyer: None. Obesity during pregnancy is associated with detrimental changes in placental function that lead to the development of complications such as gestational diabetes and preeclampsia as well as altered metabolism in the offspring. With the incidence of obesity reaching epidemic levels world-wide, it is imperative to find mechanisms to mitigate these risks during pregnancy. The gut-microbiome is a diverse system that regulates numerous body functions through the secretion of specific metabolites. Gut dysbiosis has recently emerged as one mechanism that contributes to placental dysfunction and clear associations between obesity and gut dysbiosis are evident. Indole-3-propionic acid (IPA) is a gut microbiome-derived metabolite that has anti-inflammatory, anti-oxidative stress and glucose regulatory functions, all of which are dysregulated in obesity. Previous studies have found diminished levels of IPA in serum of women with overweight/obesity. However, it remains unknown what the physiological functions of IPA are in the placenta and if it could have potential protective effects against perturbations caused by obesity. The objective of this study is to determine what physiological role IPA plays in the placenta and if IPA can protect against obesogenic insults that contribute to placental pathology. For this study, we developed an in vitro model of obesity where two human placental cell lines, BeWo (choriocarcinoma) and HTR8 (normal immortalized trophoblasts) were cultured in media conditioned by mature human adipocytes (ACM). RNA sequencing (RNAseq) analysis was used to determine acute effects of IPA treatment after 24 hours in the presence and absence of ACM. We further examined the influence of IPA on insulin signaling with physiological and hyperinsulinemia levels of insulin at 24 and 72 hours utilizing QPCR and western blot analyses. RNAseq analysis revealed treatment with physiological levels of IPA induced changes in genes associated with normal placental function, autophagy and inflammatory mediated processes and other pathways. Our RNAseq analysis offers initial insight into the molecular mechanisms of IPA in placental cells. Future analyses will investigate the potential role of insulin signaling, glucose homeostasis and oxidative stress. Collectively, this study highlights the importance of a healthy gut microbiome and potentially serves as a window of opportunity to mitigate the onset or severity of pregnancy-related disorders such as gestational diabetes by enhancing the gut microbiome prior to pregnancy. Presentation: 6/1/2024

Increasing plant protein in the diet induces changes in the plasma metabolome that may be beneficial for metabolic health. A randomized crossover study in males

Background & aimDietary shifts replacing animal protein (AP) with plant protein (PP) sources have been associated with lowering cardiometabolic risk (CMR), but underlying mechanisms are poorly characterized. This nutritional intervention aims to characterize the metabolic changes induced by diets containing different proportions of AP and PP sources in males at CMR. DesignThis study is a 4-week, crossover, randomized, controlled-feeding trial in which 19 males with CMR followed two diets providing either 36% for the control diet (CON-D) or 64% for the flexitarian diet (FLEX-D) of total protein intake from PP sources. Plasma nontargeted metabolomes (LC-MS method) were measured in the fasted state and after a high-fat challenge meal at the end of each intervention arm. Lipogenesis and protein synthesis fluxes, flow-mediated dilatation (FMD) and gluco-lipidic responses were assessed after the challenge meal. Data were analyzed with mixed models, and univariate and multivariate models for metabolomics data. ResultsIn both arms CMR improved with time, with decreased body weight (-0.9%), insulin resistant (-34%, HOMA-IR, Homeostatic Model Assessment for Insulin Resistance) and low-density lipoproteins (LDL)-cholesterol (-11%). Diet had no effect on FMD or metabolic fluxes, but a trend was observed for a stronger decrease in HOMA-IR and lower postprandial glucose after FLEX-D vs CON-D. The abundance of 21 and 37 metabolites differed between diets at fasted and fed states, respectively, including food intake biomarkers of AP (methylhistidine, eicosapentaenoic acid, hydroxyprolines) and PP sources (trigonelline, N-acetyl-ornithine). In fasted or fed states, indole acrylic acid and indole propionic acid, both products of tryptophan catabolism, were higher after FLEX-D vs CON-D, while the indispensable amino acids-related metabolites alpha-aminoadipic acid, hydroxymethylbutyric acids and propionylcarnitine were lower. In the postprandial state only, the ω-oxidation products dodecanedioic, tetradecanedioic and hexadecanedioic acids were higher after FLEX-D vs CON-D. ConclusionsDespite little changes in risk factors after 4 wk, this study evidenced subtle metabolic adaptations in amino acids and lipid metabolism and gut microbiota activity occurring after higher PP source intake that may be beneficial to CMR. ClinicalTrials.gov study identifierNCT04236518 Clinical Trial RegistryNCT04236518 on ClinicalTrials.gov

Effect of phytohormones on the carbon sequestration performance of CO2 absorption-microalgae conversion system under low light restriction

Microalgae have the potential to fix CO2 into valuable compounds. Low photosynthetic efficiency caused by low light was one of the challenges faced by microalgae carbon sequestration. In this study, Melatonin (MT) and indole-propionic acid (IPA) were used to alleviate the growth inhibition of Spirulina in CAMC system under low light restriction. The results showed that MT and IPA increased biomass and carbon fixation capacity. 10 mg/L IPA group achieved the maximum biomass and carbon fixation capacity, which were 17.11% and 21.46% higher than control. MT and IPA promoted the synthesis of chlorophyll, which in turn captured more light energy for microalgae growth. The increase of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) activities enhanced the resistance of microalgae to low light stress. MT and IPA promoted the secretion of extracellular polymeric substances (EPS) which was benefit to protect cells. The maximum phycocyanin content and yield was found in 10 mg-IPA group, which was 20.67% and 46.67% higher than control. MT and IPA improved the synthesis of carbohydrates and proteins and increased carbohydrates and proteins yield. This indicated that adding phytohormones was an effective method to alleviate the growth of microalgae restricted by low light stress, which provided a theoretical guidance for the application of CAMC system in CO2 capture and resource utilization.

Mendelian randomization identifies causal associations between GWAS-associated bacteria and their metabolites and rheumatoid arthritis.

Accumulating evidence suggests that an imbalance of gut microbiota is commonly observed in patients with rheumatoid arthritis (RA). However, it remains unclear whether gut microbiota dysbiosis is a cause or consequence of RA, and the mechanisms by which gut dysbiosis contributes to RA have not been fully understood. This study aimed to investigate the causal relationship between gut microbiota and metabolites with RA. A two-sample Mendelian randomization analysis was performed to estimate the causality of gut microbiota and metabolites on RA. A genome-wide association study (GWAS) of 211 gut microbiota and 217 metabolites was used as the exposure, whereas RA was treated as the outcome. Inverse variance weighted (IVW) was regarded as the primary approach for calculating causal estimates. MR Egger method, Weighted median method, Simple mode method, and weighted mode method were used for sensitive analysis. Metabolic pathway analysis was performed via the web-based Metaconflict 5.0. Additionally, an animal study was undertaken to evaluate the results inferred by Mendelian randomization. This study indicated that six gut microbiota taxa (RuminococcaceaeUCG013, Erysipelotrichia, Erysipelotrichaceae, Erysipelotrichales, Clostridia, and Veillonellaceae) were estimated to exert a positive impact on RA. Conversely, seven gut microbiota taxa (Oxalobacter, Cyanobacteria, RuminococcaceaeUCG002, LachnospiraceaeUCG010, Christensenellaceae, Oxalobacteraceae, Anaerostipes) were estimated to exert a negative impact on RA. Three metabolites, namely indole-3-propionate (IPA), glycine and sphingomyelin (SM 16:1), were found to be linked to lower RA risk, while five metabolites (argininosuccinate, CE 20_4, TAG 58_8, PC 40_6, and LPC 20_4) were linked to higher RA risk. Additionally, four metabolic pathways were identified by metabolic pathway analysis. The collagen-induced arthritis (CIA) rats exhibited a higher relative abundance of Class_Clostridia and a lower abundance of Genus_Lachnospiraceae (p < 0.05) than the healthy controls. This study identified causal associations between specific gut microbiota, metabolites, and RA. These findings support the significant role of gut microbiota and metabolites in RA pathogenesis.

Indole-3-propionic acid enhances growth performance and reduces diarrhea via modulating redox status and intestinal inflammation in weaned piglets

Indole-3-propionic acid (IPA) has anti-inflammatory properties, which can be beneficial for weaned piglets with underdeveloped immune systems. The study explores the impact of IPA supplementation on growth performance, oxidative stress, and inflammation response in weaned piglets. In experiment (Exp.) 1, ninety weaned piglets were divided into six groups (five replicates per group, three pigs per replicate), with each group receiving a basal diet with varying amounts of IPA (0, 50, 100, 200, 400, or 600 mg/kg) for 42 d. Piglets fed the diets with 50, 100, and 200 mg/kg of IPA exhibited reduced feed conversion ratios (F: G) compared to the control piglets (P = 0.035). Notably, 50 and 100 mg/kg IPA treatments significantly reduced diarrhea incidence and serum interleukin (IL)-6 content (P < 0.05). Conversely, a high dosage of 600 mg/kg IPA led to increased serum contents of tumor necrosis factor (TNF)-α, and IL-6 (P < 0.05). Optimal antioxidant benefits were observed at 100 mg/kg IPA supplementation, which significantly reduced malondialdehyde levels while enhancing serum total antioxidant capacity and total superoxide dismutase activity on d 14 (P < 0.05). Exp. 2 investigated the effects of IPA on lipopolysaccharide (LPS) challenge in weaned piglets. The study consisted of 32 weaned piglets allocated into 4 groups, with 8 replicates per group and 1 piglet per replicate: a control group, a LPS challenge group, a LPS challenge group supplemented with 100 mg/kg IPA, and a group supplemented with 100 mg/kg IPA alone. Upon administration of LPS or saline injection, the results indicated that dietary IPA supplementation in challenged piglets enhanced villus height: crypt depth, modulated IL-8 and IL-22 mRNA relative expression, and increased the tight junction protein claudin-1 mRNA relative expression in the intestinal mucosa (P < 0.05). These findings suggest that dietary supplementation of IPA at specific concentrations significantly improves growth performance, reduces diarrhea incidence, and mitigates inflammation and oxidative stress in weaned piglets. It may be concluded that incorporating IPA into the diet of weaned piglets can effectively improve their health and development.

ACSM2B rs73530508 polymorphism affects susceptibility to esophageal cancer by regulating indolepropionic acid levels

BackgroundTryptophan metabolism is involved in esophageal carcinogenesis. However, its genetic mechanisms remain unclear. This study aimed to investigate the effect of genetic variants that encode tryptophan metabolism on susceptibility to esophageal cancer (EC) and elucidate the mechanisms underlying genetic variation in EC progression. MethodsAge- and sex-matched cohorts of 167 patients with EC and 236 healthy controls were enrolled in this study. The concentrations of tryptophan and its metabolites were determined by self-assembled high-performance liquid chromatography-tandem mass spectrometry. High-throughput sequencing techniques were utilized to detect candidate coding genetic variants, and dominant genetic models were used to elucidate the genotypic associations. ResultsTryptophan metabolism was significantly imbalanced in patients with EC, with elevated indolepropionic acid (IPA) levels reducing the risk of EC susceptibility. ACSM2B rs73530508 (A > G) mutation was associated with higher IPA levels in vivo (P = 0.0004, false discovery rate [FDR] = 0.0092) and significantly reduced the risk of EC susceptibility (odds ratio [OR]: 0.576, Padj = 0.0161). Mediation effect analysis indicated that single-nucleotide polymorphism may inhibit carcinogenesis by reducing IPA metabolism and excretion with a mediation effect of 45.54%. ConclusionsThis study identifies the potential mechanism of ACSM2B rs73530508 (A > G) in esophageal carcinogenesis and its role in driving increased IPA levels, thereby suppressing the risk of development.

The Neuroprotective Role of Indole-3-Propionic Acid in Migraine Pathophysiology.

Background and Objectives: Migraine is a leading cause of disability worldwide, with complex pathophysiological mechanisms involving oxidative and nitrosative stress. Recent research suggests that Indole-3-Propionic Acid (IPA) may have a neuroprotective role in reducing nitrosative stress. This study aims to elucidate the roles of IPA and nitrosative stress biomarkers in migraine patients, focusing on their potential as therapeutic targets. Materials and Methods: This cross-sectional, case-control study included 57 migraine patients and 30 healthy controls. Patients were categorized into episodic migraine (EM) and chronic migraine (CM) groups. Socio-demographic and clinical characteristics were documented through structured interviews. Validated scales such as the Visual Analog Score (VAS), Headache Impact Test 6 (HIT-6), Migraine Disability Assessment Test (MIDAS), Migraine 24 h Quality of Life Scale (24 h QoL), Mini-Mental State Examination (MMSE), and Migraine Attacks-Subjective Cognitive Impairments Scale (Mig-SCog) were administered. Venous blood samples were collected, and serum levels of IPA, Nitric Oxide (NO), Nitric Oxide Synthase (NOS), and Peroxynitrite (ONOO-) were measured using ELISA and spectrophotometric methods. Results: Significant differences in serum IPA and NO levels were observed between migraine patients and controls. Specifically, higher serum IPA levels were found in the EM group, while higher serum NO levels were observed in the CM group. Elevated NO levels correlated with increased migraine attack frequency. Conversely, serum IPA levels showed a negative correlation with attack frequency, suggesting a protective role. Specifically, NO levels were positively correlated with the number of painful days, NSAID usage, VAS scores, HIT-6 scores, and MIDAS scores, while negatively correlated with 24 h QoL scores. Conclusions: The study highlights the significant involvement of IPA and nitrosative stress in migraine pathophysiology. Elevated IPA levels, particularly in EM patients, suggest its potential neuroprotective role. These findings underscore the importance of targeting oxidative and nitrosative stress pathways in developing effective migraine therapies.

Phytohormones enhanced carbon fixation and biomass production in CO2 absorption-microalgae conversion system under light stress

CO2 absorption-microalgae conversion (CAMC) system can be a sustainable technology to achieve low-energy carbon capture and resource utilization in response to zero carbon. However, light stress could restrict the carbon utilization efficiency of CAMC system. In this study, melatonin (MT) and indole-propionic acid (IPA) as phytohormones, were used to promote the carbon fixation capacity and biomass yield of CAMC system under light stress, and the potential mechanism was also discussed. Both MT and IPA promoted the growth of Spirulina, and 10 mg-MT group obtained the highest biomass and carbon fixation capacity, which were 27.61 % and 30.62 % higher than control. MT and IPA promoted the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR), enhancing antioxidant activity to avoid oxidative damage. The results of transmission electron microscopy (TEM) and cell apoptosis showed MT and IPA reduced cell membrane damage and apoptosis. Phytohormones induced the carbon flux flow to the synthesis of carbohydrate and protein, and increased carbohydrate and protein productivity. Moreover, the maximum phycocyanin content and yield were 13.74 % and 43.25 % higher than the control. Therefore, adding phytohormones was an effective strategy to achieve high-value bioresources of microalgae in CAMC system under light stress.

Potential mechanism prediction of indole-3-propionic acid against diminished ovarian reserve via network pharmacology, molecular docking and experimental verification

BackgroundOxidative stress (OS) is one of the major causes of ovarian aging and dysfunction. Indole-3-propionic acid (IPA) is an indole compound derived from tryptophan with free radical scavenging and antioxidant properties, and thus may have potential applications in protecting ovarian function, although the exact mechanisms are unknown. This study aims to preliminarily elucidate the potential mechanisms of IPA that benefit ovarian reserve function through network pharmacology, molecular docking, and experimental verification.MethodsThe related protein targets of IPA were searched on SwissTargetPrediction, TargetNet, BATMAN-TCM, and PharmMapper databases. The potential targets of diminished ovarian reserve (DOR) were identified from OMIM, GeneCards, DrugBank, and DisGeNET databases. The common targets were uploaded directly to the STRING database to construct PPI networks. We then performed GO and KEGG enrichment analysis on the targets. Subsequently, molecular docking and molecular dynamics simulation were used to validate the binding conformation of IPA to candidate targets. Furthermore, we carried out in vitro experiments to validate the prediction results of network pharmacology.ResultsWe identified a total of 61 potential targets for the interaction of IPA with DOR. The PPI network topological parameter analysis yielded 13 hub genes for DOR treatment. The GO biological process enrichment analysis identified 293 entries, mainly enriched in aging, signal transduction, response to hypoxia, negative regulation of apoptotic process, and positive regulation of cell proliferation. The KEGG enrichment analysis mainly included lipid and atherosclerosis, progesterone-mediated oocyte maturation, AGE-RAGE, relaxin, estrogen, and other signaling pathways. The molecular docking further revealed the direct binding of IPA with six hub proteins including NOS3, AKT1, EGFR, PPARA, SRC, and TNF. In vitro experiments showed that IPA pretreatment attenuated H2O2-induced cellular oxidative stress damage, while IPA exerted cytoprotective and antioxidant damage effects by regulating the six hub genes and antioxidant proteins.ConclusionWe systematically illustrated the potential protective effects of IPA against DOR through multiple targets and pathways using network pharmacology, and further verified the cytoprotective effect and antioxidant properties of IPA through in vitro experiments. These findings provide new insights into the targets and molecular mechanisms whereby IPA improves DOR.

Indole‑3‑propionic acid alleviates intestinal epithelial cell injury via regulation of the TLR4/NF‑κB pathway to improve intestinal barrier function.

Indole‑3‑propionic acid (IPA), a product of Clostridium sporogenes metabolism, has been shown to improve intestinal barrier function. In the present study, in vitro experiments using NCM460 human colonic epithelial cells were performed to investigate how IPA alleviates lipopolysaccharide (LPS)‑induced intestinal epithelial cell injury, with the aim of improving intestinal barrier function. In addition, the underlying mechanism was explored. NCM460 cell viability and apoptosis were measured using the Cell Counting Kit‑8 assay and flow cytometry, respectively. The integrity of the intestinal epithelial barrier was evaluated by measuring transepithelial electrical resistance (TEER). The underlying molecular mechanism was explored using western blotting, immunofluorescence staining, a dual luciferase reporter gene assay and quantitative PCR. The results showed that 10 µg/ml LPS induced the most prominent decrease in cell viability after 24 h of treatment. By contrast, IPA effectively inhibited LPS‑induced apoptosis in the intestinal epithelial cells. Additionally, >0.5 mM IPA improved intestinal barrier function by increasing TEER and upregulating the expression of tight junction proteins (zonula occludens‑1, claudin‑1 and occludin). Furthermore, IPA inhibited the release of pro‑inflammatory cytokines (IL‑1β, IL‑6 and TNF‑α) in a dose‑dependent manner and this was achieved via regulation of the Toll‑like receptor 4 (TLR4)/myeloid differentiation factor 88/NF‑κB and TLR4/TRIF/NF‑κB pathways. In conclusion, IPA may alleviate LPS‑induced inflammatory injury in human colonic epithelial cells. Taken together, these results suggest that IPA may be a potential therapeutic approach for the management of diseases characterized by LPS‑induced intestinal epithelial cell injury and intestinal barrier dysfunction.

Interplay between gut microbiota and tryptophan metabolism in type 2 diabetic mice treated with metformin.

This study provides valuable insights into the interrelationship between metformin administration, changes in the tryptophan (TRP) metabolome, and gut microbiota in type 2 diabetes mellitus (T2DM) mice. Indole-3-lactic acid (ILA)/indole-3-propionic acid (IPA) emerges as a potential biomarker for the development of T2DM and prediction of therapeutic response. While the indole metabolic pathway has long been associated exclusively with the gut microbiome, recent research has demonstrated the ability of host interleukin-4-induced-1 to metabolize TRP. The detection of indole derivatives in the serum of germ-free mice suggests the existence of inherent endogenous indole metabolic pathways. These findings deepen our understanding of metformin's efficacy in correcting TRP metabolic disorders and provide valuable directions for further investigation. Moreover, this knowledge may pave the way for the development of targeted treatment strategies for T2DM, focusing on the gut microbiome and restoration of associated TRP metabolism.

Effect of the novel anti-NGF monoclonal antibody DS002 on the metabolomics of pain mediators, cartilage and bone.

The anti-nerve growth factor antibody class of drugs interrupts signaling by blocking NGF binding to TrkA receptors for the treatment of pain; however, this target class of drugs has been associated with serious adverse effects in the joints during clinical trials. DS002 is a novel anti-nerve growth factor antibody drug independently developed by Guangdong Dashi Pharmaceuticals. The main purpose of this study is to explore the correlation between DS002 and pain as well as cartilage and bone metabolism with the help of metabolomics technology and the principle of enzyme-linked reaction, and to examine whether DS002 will produce serious adverse effects in joints caused by its same target class of drugs, in order to provide more scientific basis for the safety and efficacy of DS002. Our results showed that DS002 mainly affected the metabolism of aromatic amino acids and other metabolites, of which six metabolites, l -phenylalanine, 5-hydroxytryptophan, 5-hydroxytryptamine hydrochloride, 3-indolepropionic acid, kynuric acid, and kynurenine, were significantly altered, which may be related to the effectiveness of DS002 in treating pain. In addition, there were no significant changes in biological indicators related to cartilage and bone metabolism in vivo, suggesting that DS002 would not have a significant effect on cartilage and bone metabolism, so we hypothesize that DS002 may not produce the serious adverse effects in joints caused by its fellow target analogs. Therefore, the Anti-NGF analgesic drug DS002 has the potential to become a promising drug in the field of analgesia, providing pain patients with an efficient treatment option without adverse effects.

The metabolic and endocrine impact of diet-derived gut microbiota metabolites on ageing and longevity

Gut dysbiosis has been recently recognized as a hallmark of ageing. At this stage of life, gut microbiota becomes depleted from bacteria involved in the production of short-chain fatty acids (SCFA), indole and its derivative indole-3-propionic acid (IPA), metabolites shown to improve host glycemic control as well as insulin sensitivity and secretion. Moreover, gut microbiota becomes enriched in pathobiont bacteria involved in the production of imidazole propionate, phenols and trimethylamine, metabolites that promote host insulin resistance and atherosclerosis. The magnitude of these changes is much more pronounced in unhealthy than in healthy ageing. On the other hand, a distinct gut microbiota signature is displayed during longevity, the most prominent being an enrichment in both SCFA and IPA bacterial producers. This short Review discusses, in an innovative and integrative way, cutting-edge research on the composition of gut microorganisms and profile of metabolites secreted by them, that are associated with a healthy and unhealthy ageing pattern and with longevity. A detailed description of the positive or detrimental metabolic effects, in the ageing host, of diet-derived gut microbial metabolites is provided. Finally, microbiota-targeted interventions that counteract gut dysbiosis associated with ageing, are briefly outlined.

Abstract Tu041: Gut microbiome Bifidobacterium is associated with improvement in severity of heart failure with reduced ejection fraction

Background: Heart failure (HF) has been associated with dysregulated gut microbiome. However, less is understood about how gut microbiome alterations relate to changes in HF severity. We sought to understand how gut microbial shifts and associated host signatures related to changes in clinical status of patients with HF with reduced ejection fraction (HFrEF). Methods: Twenty-six adults with HFrEF were recruited and completed 2 study visits approximately 6 months apart. At each visit they provided stool sample for microbiome profiling (metagenomic sequencing), and fasting blood samples for untargeted metabolomics (liquid chromatography–mass spectrometry) and cytokine assay (Luminex antibody-conjugated bead capture). Subjects also completed dietary surveys. Clinical improvement was measured as between-visit change in the New York Heart Association (NYHA) class. Results: Between-visit NYHA class improved in 6 individuals; 20 patients remained stable or worsened. After accounting for demographics, body mass index, and diet, genus Bifidobacterium was significantly enriched in the improved group and increased over time (Figure 1). Bifidobacterium was directly associated with circulating malonic acid, which is implicated in cardio-protection and cardiomyocyte regeneration, and with indole-3-propionate (IPA), anti-inflammatory gut microbial metabolite of dietary tryptophan (Figure 2). There was also a positive correlation between Bifidobacterium and IL10, a major anti-inflammatory cytokine that plays a role in cardiac remodeling. Conclusion: Bifidobacterium was independently associated with longitudinal improvement in functional status in patients with HFrEF. Additionally, Bifidobacterium correlated with circulating IPA, malonic acid, and IL10. Our findings support (1) gut Bifidobacterium as a potential biomarker of clinical improvement in HFrEF and a possible new therapeutic target, and (2) potential downstream mediators through which Bifidobacterium may regulate HF pathophysiology.

Gut microbiota-derived indole-3-propionic acid alleviates diabetic kidney disease through its mitochondrial protective effect via reducing ubiquitination mediated-degradation of SIRT1

IntroductionGut microbes and their metabolites play crucial roles in the pathogenesis of diabetic kidney disease (DKD). However, which one and how specific gut-derived metabolites affect the progression of DKD remain largely unknown. ObjectivesThis study aimed to investigate the potential roles of indole-3-propionic acid (IPA), a microbial metabolite of tryptophan, in DKD. MethodsMetagenomic sequencing was performed to analyze the microbiome structure in DKD. Metabolomics screening and validation were conducted to identify characteristic metabolites associated with DKD. The protective effect of IPA on DKD glomerular endothelial cells (GECs) was assessed through in vivo and in vitro experiments. Further validation via western blot, immunoprecipitation, gene knockout, and site-directed mutation elucidated the mechanism of IPA on mitochondrial injury. ResultsAlterations in gut microbial community structure and dysregulated tryptophan metabolism were evident in DKD mice. Serum IPA levels were significantly reduced in DKD patients and correlated with fasting blood glucose, HbA1c, urine albumin-to-creatinine ratio (UACR), and estimated glomerular filtration rate (eGFR). IPA supplementation ameliorated albuminuria, bolstered the integrity of the glomerular filtration barrier, and mitigated mitochondrial impairments in GECs. Mechanistically, IPA hindered SIRT1 phosphorylation-mediated ubiquitin–proteasome degradation, restoring SIRT1′s role in promoting PGC-1α deacetylation and nuclear translocation, thereby upregulating genes associated with mitochondrial biosynthesis and antioxidant defense. ConclusionOur findings underscore the potential of the microbial metabolite IPA to attenuate DKD progression, offering novel insights and potential therapeutic strategies for its management.