Cell migration and proliferation capacity of IPEC-J2 cells after short-chain fatty acid exposure.

Novel antimicrobial strategies are necessary to tackle using antibiotics during the suckling and weaning period of piglets, often characterized by E. coli-induced diarrhea. In the last decades, acetate, propionate, and butyrate, all short-chain fatty acids (SCFAs), have been proposed as an alternative to antibiotics. SCFAs are instrumental in promoting the proliferation of enterocytes, preserving intestinal integrity, and modulating the microbial community by suppressing the growth of pathogenic bacteria in pigs. The effect of individual SCFAs (proprionate, acetate and butyrate) on the regenerative capacity of intestinal cells was investigated via an optimized wound-healing assay in IPEC-J2 cells, a porcine jejunal epithelial cell line. IPEC-J2 cells proved a good model as they express the free fatty acid receptor 2 (FFAR2), an important SCFA receptor with a high affinity for proprionate. Our study demonstrated that propionate (p = 0.005) and acetate (p = 0.037) were more effective in closing the wound than butyrate (p = 0.190). This holds promise in using SCFA's per os as an alternative to antibiotics.

PRM1201 effectively inhibits colorectal cancer metastasis via shaping gut microbiota and short- chain fatty acids.

BACKGROUND: PRM1201 is a traditional medicine with beneficial effects against colorectal cancer (CRC) metastasis. However, the underlying mechanism of this action remains to be determined. HYPOTHESIS: Remodeling microbiota and short-chain fatty acids (SCFAs) metabolism might be a potential mechanism to explain the anti-metastatic action of PRM1201, as this gut-microbiota dependent effect involves downregulation of histone deacetylation and EMT. METHODS: To investigate this possibility, clinical specimens were sequenced and the correlation between the anti-metastatic efficacy of PRM1201 and the restoration of SCFA-producing bacteria was studied. To obtain solid causal evidence, a mouse metastasis model was established to detect the influence of PRM1201 on cancer metastasis. Specifically, 16S amplicon sequencing, ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis, and bacterial manipulation were used to examine the gut microbiota-driven anti-metastatic action of PRM1201. RESULTS: Clinical data showed that PRM1201 increased both the number of SCFA-producing bacteria and generation of SCFAs in the feces of CRC patients. A positive correlation between the anti-metastatic efficacy of PRM1201 and the restoration of SCFAs observed. The animal experiments demonstrated that PRM1201 effectively blocked CRC metastasis in a dose-dependent manner. PRM1201 treatment modulated the composition of gut microbiota, and promoted the proliferation of beneficial SCFAs producers such as Akkermansia, Lachnospiraceae_NK4A136_group and Blautia, while simultaneously reducing the abundance of pathogenic bacteria like Escherichia-Shigella. In addition, PRM1201 led to augmentation of SCFAs content. Further results indicated that the anti-cancer metastatic mechanism of PRM1201 was linked to inhibition of histone deacetylation and suppression of epithelial-to-mesenchymal transition (EMT) in metastatic lesions. Microbiota depletion treatment and fecal microbiota transplantation (FMT) underscored the microbiota-dependent nature of this phenomenon. Moreover, this anti-colorectal cancer metastatic effect and mechanism of total SCFAs and single SCFA were also confirmed. CONCLUSION: In summary, PRM1201 exerts its anti-metastatic effects by modulating SCFA-producing bacteria and enhancing the production of SCFAs. Furthermore, the prebiotic-like actions of PRM1201, along with the PRM1201-treated bacteria, function as inhibitors of histone deacetylases (DHACs) thereby effectively suppressing EMT events.

TLR5 ligand induces the gene expression of antimicrobial peptides and CXCL8 through IL-1ß gene expression in cultured rumen epithelial cells.

High grain feeding or weaning, which could compromise the rumen epithelium by increasing ruminal short-chain fatty acid (SCFA) concentrations with pH reduction, is associated with high levels of ruminal toll-like receptor 5 (TLR5). This study aimed to determine the role of TLR5 in the rumen epithelium. Immunohistochemistry revealed that TLR5 was localized in cells on the basal side (i.e., basal and spinous layers) rather than in the granular layer in the rumen epithelium, where tight junctions are most potent, in pre- and post-weaning calves (n = 9). Primary bovine rumen epithelial cells (BRECs) obtained from Holstein cows (n = 3) were cultured to investigate the factors that upregulate TLR5; however, SCFA, low pH (pH 5.6), BHBA, L-lactate, D-lactate, and LPS did not upregulate TLR5 gene expression in BREC. Primary BREC treated with flagellin (TLR5 ligand) had higher expression of interleukin-1ß (IL-1ß) (P < 0.05) than BREC treated with vehicle. In addition, BREC treated with IL-1ß had higher expression of antimicrobial peptides and C-X-C motif chemokine ligand 8 than BREC treated with vehicle (P < 0.05). These results suggest that ruminal TLR5 may recognize epithelial disruption via flagellin and mediate the immune response via IL-1ß during high-grain feeding or weaning.

Short-chain fatty acids abrogate Japanese encephalitis virus-induced inflammation in microglial cells via miR-200a-3p/ZBTB20/IKßα axis.

Japanese encephalitis virus (JEV), a member of the Flaviviridae family, is a leading cause of viral encephalitis in humans. Survivors of this infection often develop lifelong neurological sequelae. Short-chain fatty acids (SCFAs) produced in the gut are vital mediators of the gut-brain axis. We aimed to study microRNA-based mechanisms of SCFAs in an in vitro model of JEV infection. N9 microglial cells were pretreated with SCFA cocktail before JEV infection. Cytokine bead analysis, immunoblotting, and PCR were performed to analyze relevant inflammatory markers. microRNA sequencing was performed using Illumina Hiseq, and bioinformatics tools were used for differentially expressed (DE) miRNAs and weighted gene co-expression network analysis (WGCNA). microRNA mimic/inhibitor experiments and luciferase assay were performed to study miRNA-target interaction. A significant reduction in monocyte chemoattractant protein (MCP1) and tumor necrosis factor alpha (TNFα) along with reduced expression of phospho-nuclear factor kappa B (phospho-NF-κB) was observed in SCFA conditions. Significant attenuation of histone deacetylase activity and protein expression was recorded. miRNA sequencing revealed 160 DE miRNAs in SCFA + JEV-treated cells at 6 h post-infection. WGCNA revealed miR-200a-3p, a hub miRNA significantly upregulated in SCFA conditions. Transcription factor ZBTB20 was bioinformatically predicted and validated as a gene target for miR-200a-3p. Further miRNA mimic/inhibitor assay demonstrated that miR-200-3p regulated ZBTB20 along with Iκßα that possibly dampened NF-κB signal activation downstream. IMPORTANCE: The gut-brain axis plays a pivotal role in the physiological state of an organism. Gut microbiota-derived metabolites are known to play a role in brain disorders including neuroviral infections. Short-chain fatty acids (SCFAs) appear to quench inflammatory markers in Japanese encephalitis virus-infected microglial cells in vitro. Mechanistically, we demonstrate the interaction between miR-200a-3p and ZBTB20 in regulating the canonical nuclear factor kappa B (NF-κB) signaling pathway via transcriptional regulation of Iκßα. Findings of this study pave the way to a better understanding of SCFA mechanisms that can be used to develop strategies against viral neuroinflammation.

Isobutyric acid enhances the anti-tumour effect of anti-PD-1 antibody.

The low response rate of immune checkpoint inhibitors (ICIs) is a challenge. The efficacy of ICIs is influenced by the tumour microenvironment, which is controlled by the gut microbiota. In particular, intestinal bacteria and their metabolites, such as short chain fatty acids (SCFAs), are important regulators of cancer immunity; however, our knowledge on the effects of individual SCFAs remains limited. Here, we show that isobutyric acid has the strongest effect among SCFAs on both immune activity and tumour growth. In vitro, cancer cell numbers were suppressed by approximately 75% in humans and mice compared with those in controls. Oral administration of isobutyric acid to carcinoma-bearing mice enhanced the effect of anti-PD-1 immunotherapy, reducing tumour volume by approximately 80% and 60% compared with those in the control group and anti-PD-1 antibody alone group, respectively. Taken together, these findings may support the development of novel cancer therapies that can improve the response rate to ICIs.

Short-chain fatty acids induced lung tumor cell death and increased peripheral blood CD4+ T cells in NSCLC and control patients ex vivo.

Background: Despite therapy advances, one of the leading causes of cancer deaths still remains lung cancer. To improve current treatments or prevent non-small cell lung cancer (NSCLC), the role of the nutrition in cancer onset and progression needs to be understood in more detail. While in colorectal cancer, the influence of local microbiota derived SCFAs have been well investigated, the influence of SCFA on lung cancer cells via peripheral blood immune system should be investigated more deeply. In this respect, nutrients absorbed via the gut might affect the tumor microenvironment (TME) and thus play an important role in tumor cell growth. Objective: This study focuses on the impact of the short-chain fatty acid (SCFA) Sodium Butyrate (SB), on lung cancer cell survival. We previously described a pro-tumoral role of glucose on A549 lung adenocarcinoma cell line. In this study, we wanted to know if SB would counteract the effect of glucose and thus cultured A549 and H520 in vitro with and without SB in the presence or absence of glucose and investigated how the treatment with SB affects the survival of lung cancer cells and its influence on immune cells fighting against lung cancer. Methods: In this study, we performed cell culture experiments with A549, H520 and NSCLC-patient-derived epithelial cells under different SB levels. To investigate the influence on the immune system, we performed in vitro culture of peripheral mononuclear blood cells (PBMC) from control, smoker and lung cancer patients with increasing SB concentrations. Results: To investigate the effect of SB on lung tumor cells, we first analyzed the effect of 6 different concentrations of SB on A549 cells at 48 and 72 hours cell culture. Here we found that, SB treatment reduced lung cancer cell survival in a concentration dependent manner. We next focused our deeper analysis on the two concentrations, which caused the maximal reduction in cell survival. Here, we observed that SB led to cell cycle arrest and induced early apoptosis in A549 lung cancer cells. The expression of cell cycle regulatory proteins and A549 lung cancer stem cell markers (CD90) was induced. Additionally, this study explored the role of interferon-gamma (IFN-γ) and its receptor (IFN-γ-R1) in combination with SB treatment, revealing that, although IFN-γ-R1 expression was increased, IFN-γ did not affect the efficacy of SB in reducing tumor cell viability. Furthermore, we examined the effects of SB on immune cells, specifically CD8+ T cells and natural killer (NK) cells from healthy individuals, smokers, and NSCLC patients. SB treatment resulted in a decreased production of IFN-γ and granzyme B in CD8+ T cells and NK cells. Moreover, SB induced IFN-γ-R1 in NK cells and CD4+ T cells in the absence of glucose both in PBMCs from controls and NSCLC subjects. Conclusion: Overall, this study highlights the potential of SB in inhibiting lung cancer cell growth, triggering apoptosis, inducing cell cycle arrest, and modulating immune responses by activating peripheral blood CD4+ T cells while selectively inducing IFN-γ-R1 in NK cells in peripheral blood and inhibiting peripheral blood CD8+ T cells and NK cells. Thus, understanding the mechanisms of action of SB in the TME and its influence on the immune system provide valuable insights of potentially considering SB as a candidate for adjunctive therapies in NSCLC.

[Effect of Zuogui Jiangtang Jieyu Formula on intestinal flora and short-chain fatty acid metabolism in rats with diabetes mellitus complicated with depression].

This study aimed to investigate the regulatory effects of Zuogui Jiangtang Jieyu Formula(ZJJ) on the intestinal flora, short chain fatty acids(SCFAs), and neuroinflammation in rats with diabetes mellitus complicated depression(DD). The DD model was established in rats and model rats were randomly divided into a model group, a positive drug(metformin + fluoxetine) group, a ZJJ low-dose group, and a ZJJ high-dose group, with eight rats in each group. Another eight rats were assigned to the blank group. Subsequently, depressive-like behavior test was conducted on the rats, and cerebrospinal fluid samples were collected to measure pro-inflammatory cytokines [interleukin-1ß(IL-1ß), interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α)]. Blood serum samples were collected to measure proteins related to the hypothalamic-pituitary-adrenal axis(HPA axis), including corticotropin-releasing hormone(CRH), adrenocorticotropic hormone(ACTH), and cortisol(CORT), as well as glucose metabolism. Gut contents were collected from each group for 16S rRNA sequencing analysis of intestinal flora and SCFAs sequencing. The results indicated that ZJJ not only improved glucose metabolism in DD rats(P<0.01) but also alleviated depressive-like behavior(P<0.05) and HPA axis hyperactivity(P<0.05 or P<0.01). Besides, it also improved the neuroinflammatory response in the brain, as evidenced by a significant reduction in pro-inflammatory cytokines in cerebrospinal fluid(P<0.05 or P<0.01). Additionally, ZJJ improved the intestinal flora, causing the intestinal flora in DD rats to resemble that of the blank group, characterized by an increased Firmicutes abundance. ZJJ significantly increased the levels of SCFAs(acetic acid, butyric acid, valeric acid, and isovaleric acid)(P<0.01). Therefore, it is deduced that ZJJ can effectively ameliorate intestinal flora dysbiosis, regulate SCFAs, and thereby improve both glucose metabolism disturbances and depressive-like behavior in DD.

Short chain fatty acids inhibit corneal inflammatory responses to TLR ligands via the ocular G-protein coupled receptor 43.

PURPOSE: Short chain fatty acids (SCFAs) produced by gut microbiota are known to play primary roles in gut homeostasis by immunomodulation partially through G-protein coupled receptors (GPR) 43. Using mouse models of TLR ligand induced keratitis, we investigated whether SCFAs and GPR43 play any regulatory roles in the pathogenesis of inflammatory responses in the eye. METHODS: Both human and mouse eyes were labeled with a specific antibody for GPR43 and imaged by a laser scanning confocal microscope. Corneal cups from naïve C57BL/6J (B6) and GPR43 knockout (KO) mice were stimulated with TLR ligands in the presence or absence of sodium butyrate overnight and then processed for RT-PCR assay for expression of GPR43 and cytokines. Keratitis was induced by Poly I:C in wild type (WT) B6, GPR43KO and chimeric mice and the disease severity was evaluated by the corneal fluorescein staining test, and infiltrating cell staining and calculating in corneal whole mount. RESULTS: GPR43 is expressed in both human and mouse eyes and the expression is bidirectionally regulated by TLR ligands and butyrate. Butyrate significantly inhibited inflammation caused by several TLR ligands such as Poly I:C, Flagellin, and CpG-ODN (TLR-3, 5 and 9 agonists, respectively) in WT, but not GPR43KO, mice. Butyrate inhibition of TLR-induced keratitis is mediated by the GPR43 expressed in tissue but not hematopoietic, cells. CONCLUSIONS: This is the first report to demonstrate of the protective effect of SCFAs on microbial keratitis, and the dynamic expression and anti-inflammatory function of GPR43 in the eye. SCFAs can modulate inflammation and immunity in the eye through GPR43.

Mitigation of Osteoclast-Mediated Arthritic Bone Remodeling By Short Chain Fatty Acids.

OBJECTIVE: The objective for this study was to evaluate the effects of short chain fatty acids (SCFAs) on arthritic bone remodeling. METHODS: We treated a recently described preclinical murine model of psoriatic arthritis (PsA), R26STAT3Cstopfl/fl CD4Cre mice, with SCFA-supplemented water. We also performed in vitro osteoclast differentiation assays in the presence of serum-level SCFAs to evaluate the direct impact of these microbial metabolites on maturation and function of osteoclasts. We further characterized the molecular mechanism of SCFAs by transcriptional analysis. RESULTS: The osteoporosis condition in R26STAT3Cstopfl/fl CD4Cre animals is attributed primarily to robust osteoclast differentiation driven by an expansion of osteoclast progenitor cells (OCPs), accompanied by impaired osteoblast development. We show that SCFA supplementation can rescue the osteoporosis phenotype in this model of PsA. Our in vitro experiments revealed an inhibitory effect of the SCFAs on osteoclast differentiation, even at very low serum concentrations. This suppression of osteoclast differentiation enabled SCFAs to impede osteoporosis development in R26STAT3Cstopfl/fl CD4Cre mice. Further interrogation revealed that bone marrow-derived OCPs from diseased mice expressed a higher level of SCFA receptors than those of control mice and that the progenitor cells in the bone marrow of SCFA-treated mice presented a modified transcriptomic landscape, suggesting a direct impact of SCFAs on bone marrow progenitors in the context of osteoporosis. CONCLUSION: We demonstrated how gut microbiota-derived SCFAs can regulate distal pathology (ie, osteoporosis) and identified a potential therapeutic option for restoring bone density in rheumatic disease, further highlighting the critical role of the gut-bone axis in these disorders.

Isocaloric diets with varying protein levels affected energy metabolism in young adult Sprague-Dawley rats via modifying the gut microbes: A lipid imbalance was brought on by a diet with a particularly high protein content.

Protein is the most important macro-nutrient when it comes to maximizing health, body composition, muscle growth, and recovery of body tissue. In recent years, it has been found that protein also plays an important role in metabolism and gut microbiota. This study was performed to investigate the effects of an isocaloric diet with different crude protein contents on the energy metabolism of Sprague-Dawley (SD) rats. Results revealed that compared with the 20% crude protein (CP; control) diet, the 38% CP diet improved serum parameters that are associated with dyslipidemia and glucose metabolic disorders in SD rats, whereas the 50% CP diet increased liver injury indicators and fatty acid synthesis-related genes and protein expression in the liver. Compared with the control diet, the 14% CP diet increased the abundance of colonic short-chain fatty acid-producing bacteria (Lachnospiraceae_NK4A136_group and Ruminiclostridium_9) and promoted colonic microbial cysteine and methionine metabolism, the 38% CP diet up-regulated colonic microbial lysine biosynthesis and degradation pathways, and the 50% CP diet down-regulated colonic mucosal cholesterol metabolism. Furthermore, the increase of multiple colonic enteropathogenic bacteria in the 50% CP group was associated with higher palmitic acid and stearic acid concentrations in the colonic microbes and lower cholesterol and arachidonic acid concentrations in the colonic mucosa. These findings revealed that the 14% CP and 38% CP diets improved rats' energy metabolism, while the 50% CP diet was accompanied by lipid metabolism imbalances and an increase in the abundance of multiple enteropathogenic bacteria.

The role and mechanism of action of microbiota-derived short-chain fatty acids in neutrophils: From the activation to becoming potential biomarkers.

Short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate, have emerged as critical mediators in the communication between the human microbiota and its host. As the first responder to the inflammatory site, neutrophils play an important role in protecting the host against bacterial infections. Recent investigations revealed that SCFAs generated from microbiota influence various neutrophil activities, including activation, migration, and generation of mediators of inflammatory processes. SCFAs have also been demonstrated to exhibit potential therapeutic benefits in a variety of disorders related to neutrophil dysfunction, including inflammatory bowel disease, viral infectious disorders, and cancer. This study aims to examine the molecular processes behind the complicated link between SCFAs and neutrophils, as well as their influence on neutrophil-driven inflammatory disorders. In addition, we will also provide an in-depth review of current research on the diagnostic and therapeutic value of SCFAs as possible biomarkers for neutrophil-related diseases.

Trans-vaccenic acid reprograms CD8+ T cells and anti-tumour immunity.

Diet-derived nutrients are inextricably linked to human physiology by providing energy and biosynthetic building blocks and by functioning as regulatory molecules. However, the mechanisms by which circulating nutrients in the human body influence specific physiological processes remain largely unknown. Here we use a blood nutrient compound library-based screening approach to demonstrate that dietary trans-vaccenic acid (TVA) directly promotes effector CD8+ T cell function and anti-tumour immunity in vivo. TVA is the predominant form of trans-fatty acids enriched in human milk, but the human body cannot produce TVA endogenously1. Circulating TVA in humans is mainly from ruminant-derived foods including beef, lamb and dairy products such as milk and butter2,3, but only around 19% or 12% of dietary TVA is converted to rumenic acid by humans or mice, respectively4,5. Mechanistically, TVA inactivates the cell-surface receptor GPR43, an immunomodulatory G protein-coupled receptor activated by its short-chain fatty acid ligands6-8. TVA thus antagonizes the short-chain fatty acid agonists of GPR43, leading to activation of the cAMP-PKA-CREB axis for enhanced CD8+ T cell function. These findings reveal that diet-derived TVA represents a mechanism for host-extrinsic reprogramming of CD8+ T cells as opposed to the intrahost gut microbiota-derived short-chain fatty acids. TVA thus has translational potential for the treatment of tumours.

Chitosan and its oligosaccharide accelerate colonic motility and reverse serum metabolites in rats after excessive protein consumption.

Excessive protein consumption (EPC) could increase the gastrointestinal burden and impair gut motility. The present study was designed to explore the improvement of chitosan (CTS) and chitosan oligosaccharide (COS) on colonic motility and serum metabolites in rats after EPC. The results of in vivo experiments fully proved that CTS and COS could improve gut motility and reverse the serum metabolites in rats as indicated by LC-MS/MS analysis, and the COS group even showed a better effect than the CTS group. Furthermore, short-chain fatty acids (SCFAs), which could promote gut motility, were also increased to alleviate EPC-induced constipation after supplementation with CTS or COS. In addition, CTS and COS could decrease the concentration of ammonia in serum and down-regulate the levels of H2S and indole. In summary, the present study revealed that CTS and COS could produce SCFAs, improve the colonic motility in rats, reverse the levels of valine, adenosine, cysteine, 1-methyladenosine, indole, and uracil, and enhance aminoacyl-tRNA biosynthesis and valine, leucine and isoleucine degradation. The present study provides novel insights into the potential roles of CTS and COS in alleviating the adverse effects of EPC.

The Role of Gut Microbiome-Derived Short-Chain Fatty Acid Butyrate in Hepatobiliary Diseases.

The short-chain fatty acid butyrate, produced from fermentable carbohydrates by gut microbiota in the colon, has multiple beneficial effects on human health. At the intestinal level, butyrate regulates metabolism, helps in the transepithelial transport of fluids, inhibits inflammation, and induces the epithelial defense barrier. The liver receives a large amount of short-chain fatty acids via the blood flowing from the gut via the portal vein. Butyrate helps prevent nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, inflammation, cancer, and liver injuries. It ameliorates metabolic diseases, including insulin resistance and obesity, and plays a direct role in preventing fatty liver diseases. Butyrate has different mechanisms of action, including strong regulatory effects on the expression of many genes by inhibiting the histone deacetylases and modulating cellular metabolism. The present review highlights the wide range of beneficial therapeutic and unfavorable adverse effects of butyrate, with a high potential for clinically important uses in several liver diseases.

Short-Chain Fatty Acids-A Product of the Microbiome and Its Participation in Two-Way Communication on the Microbiome-Host Mammal Line.

PURPOSE OF REVIEW: The review aims to describe short-chain fatty acids (SCFAs) as metabolites of bacteria, their complex influence on whole-body metabolism, and alterations in the SCFA profile in obesity and after bariatric surgery (BS). RECENT FINDINGS: The fecal profile of SCFAs in obese patients differs from that of lean patients, as well as their gut microbiota composition. In obese patients, a lower diversity of bacteria is observed, as well as higher concentrations of SCFAs in stool samples. Obesity is now considered a global epidemic and bariatric surgery (BS) is an effective treatment for severe obesity. BS affects the structure and functioning of the digestive system, and also alters gut microbiota and the concentration of fecal SCFAs. Generally, after BS, SCFA levels are lower but levels of branched short-chain fatty acids (BSCFAs) are elevated, the effect of which is not fully understood. Moreover, changes in the profile of circulating SCFAs are little known and this is an area for further research. Obesity seems to be inherently associated with changes in the SCFA profile. It is necessary to better understand the impact of BS on microbiota and the metabolome in both feces and blood as only a small percentage of SCFAs are excreted. Further research may allow the development of a personalized therapeutic approach to the BS patient in terms of diet and prebiotic intervention.

Fecal levels of SCFA and BCFA during capecitabine in patients with metastatic or unresectable colorectal cancer.

BACKGROUND: Gut bacteria-derived short-chain fatty acids (SCFA) and branched-chain fatty acids (BCFA) are considered to have beneficial metabolic, anti-inflammatory as well as anti-carcinogenic effects. Previous preclinical studies indicated bidirectional interactions between gut bacteria and the chemotherapeutic capecitabine or its metabolite 5-FU. This study investigated the effect of three cycles of capecitabine on fecal SCFA and BCFA levels and their associations with tumor response, nutritional status, physical performance, chemotherapy-induced toxicity, systemic inflammation and bacterial abundances in patients with colorectal cancer (CRC). METHODS: Forty-four patients with metastatic or unresectable CRC, scheduled for treatment with capecitabine (± bevacizumab), were prospectively enrolled. Patients collected a fecal sample and completed a questionnaire before (T1), during (T2) and after (T3) three cycles of capecitabine. Tumor response (CT/MRI scans), nutritional status (MUST score), physical performance (Karnofsky Performance Score) and chemotherapy-induced toxicity (CTCAE) were recorded. Additional data on clinical characteristics, treatment regimen, medical history and blood inflammatory parameters were collected. Fecal SCFA and BCFA concentrations were determined by gas chromatography-mass spectrometry (GC-MS). Gut microbiota composition was assessed using 16S rRNA amplicon sequencing. RESULTS: Fecal levels of the SCFA valerate and caproate decreased significantly during three cycles of capecitabine. Furthermore, baseline levels of the BCFA iso-butyrate were associated with tumor response. Nutritional status, physical performance and chemotherapy-induced toxicity were not significantly associated with SCFA or BCFA. Baseline SCFA correlated positively with blood neutrophil counts. At all time points, we identified associations between SCFA and BCFA and the relative abundance of bacterial taxa on family level. CONCLUSIONS: The present study provided first indications for a potential role of SCFA and BCFA during capecitabine treatment as well as implications for further research. TRIAL REGISTRATION: The current study was registered in the Dutch Trial Register (NTR6957) on 17/01/2018 and can be consulted via the International Clinical Trial Registry Platform (ICTRP).

Neuroprotective effect of short-chain fatty acids against oxidative stress-induced SH-SY5Y injury via GPR43-dependent pathway.

A neurodegenerative disorder is a condition that causes a degeneration of neurons in the central nervous system, leading to cognitive impairment and movement disorders. An accumulation of oxidative stress in neurons contributes to the pathogenesis of neurodegenerative disorders. Over the past few years, several studies have suggested that short-chain fatty acids, metabolites of the gut microbiota, might have a beneficial effect in neurodegenerative disorders. A G protein-coupled receptor 43 (GPR43) plays an important role in modulating oxidative stress and inflammatory processes in several tissues. Interestingly, the downstream signaling pathways activated by GPR43 to modulate oxidative stress differ among tissues. Moreover, the cellular mechanisms underlying GPR43 activation in neuronal cells to handle oxidative stress remain unclear. In this present study, we tested the role of GPR43, which is activated by short-chain fatty acids or a specific GPR43 agonist, in an oxidative stress-induced neuronal cell line (SH-SY5Y) injury. Our findings suggest that a combination of short-chain fatty acids with a physiological function could protect neurons from H2 O2 -induced cell damage. The effect of short-chain fatty acids mixture was abolished by pretreatment with a GPR43 antagonist, indicating this protective effect is a GPR43-dependent mechanism. In addition, a specific GPR43 agonist shows a similar result to that found in short-chain fatty acids mixture. Furthermore, our findings indicate that the downstream activation of GPR43 to protect against oxidative stress-induced neuronal injury is a biased Gq activation signaling of GPR43, which results in the prevention of H2 O2 -induced neuronal apoptosis. In conclusion, our results show new insight into the cellular mechanism of GPR43 and its neuroprotective effect. Taken together, this newly discovered finding suggests that activation of the biased Gq signaling pathway of GPR43 might be a potential therapeutic target for aging-related neurodegeneration.

Short-Chain Fatty Acids Attenuate 5-Fluorouracil-Induced THP-1 Cell Inflammation through Inhibiting NF-κB/NLRP3 Signaling via Glycerolphospholipid and Sphingolipid Metabolism.

5-Fluorouracil (5-FU) is a common anti-tumor drug, but there is no effective treatment for its side effect, intestinal mucositis. The inflammatory reaction of macrophages in intestinal mucosa induced by 5-FU is an important cause of intestinal mucositis. In this study, we investigated the anti-inflammatory effects of the three important short-chain fatty acids (SCFAs), including sodium acetate (NaAc), sodium propionate (NaPc), and sodium butyrate (NaB), on human mononuclear macrophage-derived THP-1 cells induced by 5-FU. The expressions of intracellular ROS, pro-inflammatory/anti-inflammatory cytokines, as well as the nuclear factor-κB/NLR family and pyrin domain-containing protein 3 (NF-κB/NLRP3) signaling pathway proteins were determined. Furthermore, the cell metabolites were analyzed by untargeted metabolomics techniques. Our results revealed that the three SCFAs inhibited pro-inflammatory factor expressions, including IL-1ß and IL-6, when treated with 5-FU (p < 0.05). The ROS expression and NF-κB activity of 5-FU-treated THP-1 cells were inhibited by the three SCFAs pre-incubated (p < 0.05). Moreover, NLRP3 knockdown abolished 5-FU-induced IL-1ß expression (p < 0.05). Further experiments showed that the three SCFAs affected 20 kinds of metabolites that belong to amino acid and phosphatidylcholine metabolism in THP-1 cells. These significantly altered metabolites were involved in amino acid metabolism and glycerolphospholipid and sphingolipid metabolism. It is the first time that three important SCFAs (NaAc, NaPc, and NaB) were identified as inhibiting 5-FU-induced macrophage inflammation through inhibiting ROS/NF-κB/NLRP3 signaling pathways and regulating glycerolphospholipid and sphingolipid metabolism.

Dietary genistein increases microbiota-derived short chain fatty acid levels, modulates homeostasis of the aging gut, and extends healthspan and lifespan.

Age-related gastrointestinal decline contributes to whole-organism frailty and mortality. Genistein is known to have beneficial effects on age-related diseases, but its precise role in homeostasis of the aging gut remains to be elucidated. Here, wild-type aging mice and Zmpste24-/- progeroid mice were used to investigate the role of genistein in lifespan and homeostasis of the aging gut in mammals. A series of longitudinal, clinically relevant measurements were performed to evaluate the effect of genistein on healthspan. It was found that dietary genistein promoted a healthier and longer life and was associated with a decrease in the levels of systemic inflammatory cytokines in aging mice. Furthermore, dietary genistein ameliorated gut dysfunctions, such as intestinal inflammation, leaky gut, and impaired epithelial regeneration. A distinct genistein-mediated alteration in gut microbiota was observed by increasing Lachnospira abundance and short-chain fatty acid (SCFA) production. Further fecal microbiota transplantation and dirty cage sharing experiments indicated that the gut microbiota from genistein-fed mice rejuvenated the aging gut and extended the lifespan of progeroid mice. It was demonstrated that genistein-associated SCFAs alleviated tumor necrosis factor alpha-induced intestinal organoid damage. Moreover, genistein-associated propionate promoted regulatory T cell-derived interleukin 10 production, which alleviated macrophage-derived inflammation. This study provided the first data, to the authors' knowledge, indicating that dietary genistein modulates homeostasis in the aging gut and extends the healthspan and lifespan of aging mammals. Moreover, the existence of a link between genistein and the gut microbiota provides a rationale for dietary interventions against age-associated frailty.

Effects of free fatty acid receptor-2 (FFAR2)-mediated signaling on the regulation of cellular functions in osteosarcoma cells.

G protein coupled free fatty acid receptors (FFARs) are involved in the pathogenesis of several human diseases. FFAR2 and FFAR3 are activated by the binding of short-chain fatty acids (SCFAs). This study aimed to evaluate the roles of FFAR2 in the regulation of cellular functions in osteosarcoma HOS cells, using acetic acid and propanoic acid as FFAR2 and FFAR3 agonists. FFAR2 and FFAR3 genes were expressed in HOS cells. The cell motile activity of HOS cells was significantly stimulated by acetic acid and propanoic acid. In contrast, acetic acid and propanoic acid had no impact on the activation of matrix metalloproteinase-2 (MMP-2) and MMP-9. In cell survival assay, the cell survival rate to cisplatin (CDDP) of HOS cells was elevated by acetic acid and propanoic acid. To assess the effects of FFAR2 on cellular functions, FFAR2 knockdown (HOS-FFAR2) cells were generated from HOS cells. The cell motile activity of HOS-FFAR2 cells was enhanced by acetic acid and propanoic acid. In the presence of acetic acid and propanoic acid, MMP-2 and MMP-9 activities were reduced in HOS-FFAR2 cells, compared with control cells. When cells were treated with acetic acid and propanoic acid, the cell survival rate to CDDP of HOS-FFAR2 cells was significantly lower than that of control cells. These results suggest that activation of FFAR2-mediated signaling is involved in the modulation of cellular functions in HOS cells.