-
Journal of Hepatology Dec 2023Recent studies have highlighted the role of the gut microbiota and their metabolites in non-alcoholic fatty liver disease-associated hepatocellular carcinoma...
BACKGROUND & AIMS
Recent studies have highlighted the role of the gut microbiota and their metabolites in non-alcoholic fatty liver disease-associated hepatocellular carcinoma (NAFLD-HCC). We aimed to identify specific beneficial bacterial species that could be used prophylactically to prevent NAFLD-HCC.
METHODS
The role of Bifidobacterium pseudolongum was assessed in two mouse models of NAFLD-HCC: diethylnitrosamine + a high-fat/high-cholesterol diet or + a choline-deficient/high-fat diet. Germ-free mice were used for the metabolic study of B. pseudolongum. Stool, portal vein and liver tissues were collected from mice for non-targeted and targeted metabolomic profiles. Two human NAFLD-HCC cell lines (HKCI2 and HKCI10) were co-cultured with B. pseudolongum-conditioned media (B.p CM) or candidate metabolites.
RESULTS
B. pseudolongum was the top depleted bacterium in mice with NAFLD-HCC. Oral gavage of B. pseudolongum significantly suppressed NAFLD-HCC formation in two mouse models (p < 0.01). Incubation of NAFLD-HCC cells with B.p CM significantly suppressed cell proliferation, inhibited the G1/S phase transition and induced apoptosis. Acetate was identified as the critical metabolite generated from B. pseudolongum in B.p CM, an observation that was confirmed in germ-free mice. Acetate inhibited cell proliferation and induced cell apoptosis in NAFLD-HCC cell lines and suppressed NAFLD-HCC tumor formation in vivo. B. pseudolongum restored heathy gut microbiome composition and improved gut barrier function. Mechanistically, B. pseudolongum-generated acetate reached the liver via the portal vein and bound to GPR43 (G coupled-protein receptor 43) on hepatocytes. GPR43 activation suppressed the IL-6/JAK1/STAT3 signaling pathway, thereby preventing NAFLD-HCC progression.
CONCLUSIONS
B. pseudolongum protected against NAFLD-HCC by secreting the anti-tumor metabolite acetate, which reached the liver via the portal vein. B. pseudolongum holds potential as a probiotic for the prevention of NAFLD-HCC.
IMPACT AND IMPLICATIONS
Non-alcoholic fatty liver disease-associated hepatocellular carcinoma (NAFLD-HCC) is an increasing healthcare burden worldwide. There is an urgent need to develop effective agents to prevent NAFLD-HCC progression. Herein, we show that the probiotic Bifidobacterium pseudolongum significantly suppressed NAFLD-HCC progression by secreting acetate, which bound to hepatic GPR43 (G coupled-protein receptor 43) via the gut-liver axis and suppressed the oncogenic IL-6/JAK1/STAT3 signaling pathway. Bifidobacterium pseudolongum holds potential as a novel probiotic for NAFLD-HCC prevention.
Topics: Animals; Humans; Mice; Carcinoma, Hepatocellular; Diet, High-Fat; Disease Models, Animal; Interleukin-6; Liver; Liver Neoplasms; Non-alcoholic Fatty Liver Disease; Acetates; Microbiota
PubMed: 37459922
DOI: 10.1016/j.jhep.2023.07.005 -
Transplant International : Official... 2023Despite advances in monitoring and treatment, cytomegalovirus (CMV) infections remain one of the most common complications after solid organ transplantation (SOT). CMV... (Review)
Review
Despite advances in monitoring and treatment, cytomegalovirus (CMV) infections remain one of the most common complications after solid organ transplantation (SOT). CMV infection may fail to respond to standard first- and second-line antiviral therapies with or without the presence of antiviral resistance to these therapies. This failure to respond after 14 days of appropriate treatment is referred to as "resistant/refractory CMV." Limited data on refractory CMV without antiviral resistance are available. Reported rates of resistant CMV are up to 18% in SOT recipients treated for CMV. Therapeutic options for treating these infections are limited due to the toxicity of the agent used or transplant-related complications. This is often the challenge with conventional agents such as ganciclovir, foscarnet and cidofovir. Recent introduction of new CMV agents including maribavir and letermovir as well as the use of adoptive T cell therapy may improve the outcome of these difficult-to-treat infections in SOT recipients. In this expert review, we focus on new treatment options for resistant/refractory CMV infection and disease in SOT recipients, with an emphasis on maribavir, letermovir, and adoptive T cell therapy.
Topics: Humans; Antiviral Agents; Cytomegalovirus; Cytomegalovirus Infections; Acetates; Ganciclovir
PubMed: 37901297
DOI: 10.3389/ti.2023.11785 -
European Respiratory Review : An... Sep 2023The United States Food and Drug Administration issued a black box warning on the mental health adverse effects of montelukast in 2020. Age-related effects on the risk of... (Review)
Review
BACKGROUND
The United States Food and Drug Administration issued a black box warning on the mental health adverse effects of montelukast in 2020. Age-related effects on the risk of developing specific neuropsychiatric events in montelukast users remain largely unknown.
OBJECTIVE
To describe the risk of neuropsychiatric events associated with montelukast in adults and children with asthma.
METHODS
A systematic search of all studies investigating neuropsychiatric events in montelukast users was performed in PubMed, the Cochrane Library and Embase from inception to 7 September 2022. Animal studies and conference abstracts were excluded.
RESULTS
59 studies (21 pharmacovigilance studies, four reviews from 172 randomised controlled trials, 20 observational studies, 10 case reports and four case series) evaluating neuropsychiatric events in patients with asthma on montelukast were reviewed. No significant association was shown between montelukast and suicide-related events in six of the observational studies. No association was found for depression as defined by the International Classification of Diseases 10 revision codes in three observational studies and a review of randomised clinical trials. However, findings from four studies using antidepressant prescriptions as the outcome identified significant associations. Consistent with nine pharmacovigilance studies, two large-scale observational studies revealed possible associations of montelukast with anxiety and sleeping disorders in adult patients with asthma, respectively. However, the results were not replicated in two observational studies on children.
CONCLUSION
Montelukast is not associated with suicide- and depression-related events in asthma patients. Older adults may be particularly susceptible to anxiety and sleeping disorders.
Topics: Child; Animals; Humans; Aged; Asthma; Acetates; Quinolines; Cyclopropanes; Anti-Asthmatic Agents
PubMed: 37758273
DOI: 10.1183/16000617.0079-2023 -
Circulation Research Jan 2024T cells are central to the immune responses contributing to hypertension. LGMN (legumain) is highly expressed in T cells; however, its role in the pathogenesis of...
BACKGROUND
T cells are central to the immune responses contributing to hypertension. LGMN (legumain) is highly expressed in T cells; however, its role in the pathogenesis of hypertension remains unclear.
METHODS
Peripheral blood samples were collected from patients with hypertension, and cluster of differentiation (CD)4+ T cells were sorted for gene expression and Western blotting analysis. TLGMNKO (T cell-specific LGMN-knockout) mice (Lgmn/CD4), regulatory T cell (Treg)-specific LGMN-knockout mice (Lgmn/Foxp3), and RR-11a (LGMN inhibitor)-treated C57BL/6 mice were infused with Ang II (angiotensin II) or deoxycorticosterone acetate/salt to establish hypertensive animal models. Flow cytometry, 4-dimensional label-free proteomics, coimmunoprecipitation, Treg suppression, and in vivo Treg depletion or adoptive transfer were used to delineate the functional importance of T-cell LGMN in hypertension development.
RESULTS
LGMN mRNA expression was increased in CD4+ T cells isolated from hypertensive patients and mice, was positively correlated with both systolic and diastolic blood pressure, and was negatively correlated with serum IL (interleukin)-10 levels. TLGMNKO mice exhibited reduced Ang II-induced or deoxycorticosterone acetate/salt-induced hypertension and target organ damage relative to wild-type (WT) mice. Genetic and pharmacological inhibition of LGMN blocked Ang II-induced or deoxycorticosterone acetate/salt-induced immunoinhibitory Treg reduction in the kidneys and blood. Anti-CD25 antibody depletion of Tregs abolished the protective effects against Ang II-induced hypertension in TLGMNKO mice, and LGMN deletion in Tregs prevented Ang II-induced hypertension in mice. Mechanistically, endogenous LGMN impaired Treg differentiation and function by directly interacting with and facilitating the degradation of TRAF6 (tumor necrosis factor receptor-associated factor 6) via chaperone-mediated autophagy, thereby inhibiting NF-κB (nuclear factor kappa B) activation. Adoptive transfer of LGMN-deficient Tregs reversed Ang II-induced hypertension, whereas depletion of TRAF6 in LGMN-deficient Tregs blocked the protective effects.
CONCLUSIONS
LGMN deficiency in T cells prevents hypertension and its complications by promoting Treg differentiation and function. Specifically targeting LGMN in Tregs may be an innovative approach for hypertension treatment.
Topics: Animals; Humans; Mice; Acetates; Angiotensin II; CD4-Positive T-Lymphocytes; Desoxycorticosterone; Hypertension; Mice, Inbred C57BL; Mice, Knockout; T-Lymphocytes, Regulatory; TNF Receptor-Associated Factor 6
PubMed: 38047378
DOI: 10.1161/CIRCRESAHA.123.322835 -
Nature Communications Jul 2023Oxidative stress plays a crucial role in the pathogenesis of hepatic encephalopathy (HE), but the mechanism remains unclear. GABAergic neurons in substantia nigra pars...
Oxidative stress plays a crucial role in the pathogenesis of hepatic encephalopathy (HE), but the mechanism remains unclear. GABAergic neurons in substantia nigra pars reticulata (SNr) contribute to the motor deficit of HE. The present study aims to investigate the effects of oxidative stress on HE in male mice. The results validate the existence of oxidative stress in both liver and SNr across two murine models of HE induced by thioacetamide (TAA) and bile duct ligation (BDL). Systemic mitochondria-targeted antioxidative drug mitoquinone (Mito-Q) rescues mitochondrial dysfunction and oxidative injury in SNr, so as to restore the locomotor impairment in TAA and BDL mice. Furthermore, the GAD2-expressing SNr population (SNr) is activated by HE. Both overexpression of mitochondrial uncoupling protein 2 (UCP2) targeted to SNr and SNr-targeted chemogenetic inhibition targeted to SNr rescue mitochondrial dysfunction in TAA-induced HE. These results define the key role of oxidative stress in the pathogenesis of HE.
Topics: Male; Animals; Mice; Hepatic Encephalopathy; Oxidative Stress; Antioxidants; Bile Ducts; Thioacetamide
PubMed: 37488119
DOI: 10.1038/s41467-023-40081-8 -
Proceedings of the National Academy of... Dec 2023Mild or transient dietary restriction (DR) improves many aspects of health and aging. Emerging evidence from us and others has demonstrated that DR also optimizes the...
Mild or transient dietary restriction (DR) improves many aspects of health and aging. Emerging evidence from us and others has demonstrated that DR also optimizes the development and quality of immune responses. However, the factors and mechanisms involved remain to be elucidated. Here, we propose that DR-induced optimization of immunological memory requires a complex cascade of events involving memory T cells, the intestinal microbiota, and myeloid cells. Our findings suggest that DR enhances the ability of memory T cells to recruit and activate myeloid cells in the context of a secondary infection. Concomitantly, DR promotes the expansion of commensal Bifidobacteria within the large intestine, which produce the short-chain fatty acid acetate. Acetate conditioning of the myeloid compartment during DR enhances the capacity of these cells to kill pathogens. Enhanced host protection during DR is compromised when Bifidobacteria expansion is prevented, indicating that microbiota configuration and function play an important role in determining immune responsiveness to this dietary intervention. Altogether, our study supports the idea that DR induces both memory T cells and the gut microbiota to produce distinct factors that converge on myeloid cells to promote optimal pathogen control. These findings suggest that nutritional cues can promote adaptation and co-operation between multiple immune cells and the gut microbiota, which synergize to optimize immunity and protect the collective metaorganism.
Topics: Microbiota; Gastrointestinal Microbiome; Fatty Acids, Volatile; Acetates
PubMed: 38011570
DOI: 10.1073/pnas.2304905120 -
Nature Cell Biology Apr 2024The ability of tumour cells to thrive in harsh microenvironments depends on the utilization of nutrients available in the milieu. Here we show that pancreatic...
The ability of tumour cells to thrive in harsh microenvironments depends on the utilization of nutrients available in the milieu. Here we show that pancreatic cancer-associated fibroblasts (CAFs) regulate tumour cell metabolism through the secretion of acetate, which can be blocked by silencing ATP citrate lyase (ACLY) in CAFs. We further show that acetyl-CoA synthetase short-chain family member 2 (ACSS2) channels the exogenous acetate to regulate the dynamic cancer epigenome and transcriptome, thereby facilitating cancer cell survival in an acidic microenvironment. Comparative H3K27ac ChIP-seq and RNA-seq analyses revealed alterations in polyamine homeostasis through regulation of SAT1 gene expression and enrichment of the SP1-responsive signature. We identified acetate/ACSS2-mediated acetylation of SP1 at the lysine 19 residue that increased SP1 protein stability and transcriptional activity. Genetic or pharmacologic inhibition of the ACSS2-SP1-SAT1 axis diminished the tumour burden in mouse models. These results reveal that the metabolic flexibility imparted by the stroma-derived acetate enabled cancer cell survival under acidosis via the ACSS2-SP1-SAT1 axis.
Topics: Animals; Mice; Cancer-Associated Fibroblasts; Cell Line, Tumor; Acetates; Pancreatic Neoplasms; Polyamines; Tumor Microenvironment
PubMed: 38429478
DOI: 10.1038/s41556-024-01372-4 -
Biomedicine & Pharmacotherapy =... Jul 2023Gut microbiota can interact with the immune system through its metabolites. Short-chain fatty acids (SCFAs), as one of the most abundant metabolites of the resident gut... (Review)
Review
Gut microbiota can interact with the immune system through its metabolites. Short-chain fatty acids (SCFAs), as one of the most abundant metabolites of the resident gut microbiota play an important role in this crosstalk. SCFAs (acetate, propionate, and butyrate) regulate nearly every type of immune cell in the gut's immune cell repertoire regarding their development and function. SCFAs work through several pathways to impose protection towards colonic health and against local or systemic inflammation. Additionally, SCFAs play a role in the regulation of immune or non-immune pathways that can slow the development of autoimmunity either systematically or in situ. The present study aims to summarize the current knowledge on the immunomodulatory roles of SCFAs and the association between the SCFAs and autoimmune disorders such as celiac disease (CD), inflammatory bowel disease (IBD), rheumatoid arthritis (RA), multiple sclerosis (MS), systemic lupus erythematosus (SLE), type 1 diabetes (T1D) and other immune-mediated diseases, uncovering a brand-new therapeutic possibility to prevent or treat autoimmunity.
Topics: Humans; Fatty Acids, Volatile; Autoimmune Diseases; Butyrates; Propionates; Acetates
PubMed: 37105078
DOI: 10.1016/j.biopha.2023.114763 -
Physiological Reports Jul 2023Short-chain fatty acids (SCFAs) are the end products of the fermentation of dietary fibers by the intestinal microbiota and reported to exert positive effects on host...
Short-chain fatty acids (SCFAs) are the end products of the fermentation of dietary fibers by the intestinal microbiota and reported to exert positive effects on host physiology. Acetate is the most abundant SCFA in humans and is shown to improve acute kidney injury in a mouse model of ischemia-reperfusion injury. However, how SCFAs protect the kidney and whether SCFAs have a renoprotective effect in chronic kidney disease (CKD) models remain to be elucidated. We investigated whether acetate and other SCFAs could attenuate the kidney damage. In in vitro experiments, cell viability of acetate-treated human kidney 2 (HK-2) cells was significantly higher than that of vehicle-treated in an oxidative stress model, and acetate reduced cellular reactive oxygen species (ROS) production. In mitochondrial analysis, the MitoSOX-positive cell proportion decreased, and transcription of dynamin-1-like protein gene, a fission gene, was decreased by acetate treatment. In in vivo experiments in mice, acetate treatment significantly ameliorated fibrosis induced by unilateral ureteral obstruction, and the oxidative stress marker phosphorylated histone H2AX (γH2AX) was also reduced. Further, acetate treatment ameliorated dysmorphic mitochondria in the proximal tubules, and ROS and mitochondrial analyses suggested that acetate improved mitochondrial damage. Our findings indicate a renoprotective effect of acetate in CKD.
Topics: Humans; Mice; Animals; Reactive Oxygen Species; Oxidative Stress; Acetates; Kidney; Fatty Acids, Volatile; Renal Insufficiency, Chronic; Fibrosis
PubMed: 37463875
DOI: 10.14814/phy2.15774 -
ELife Oct 2023Accumulating evidence indicates that acetate is increased under energy stress conditions such as those that occur in diabetes mellitus and prolonged starvation. However,...
Accumulating evidence indicates that acetate is increased under energy stress conditions such as those that occur in diabetes mellitus and prolonged starvation. However, how and where acetate is produced and the nature of its biological significance are largely unknown. We observed overproduction of acetate to concentrations comparable to those of ketone bodies in patients and mice with diabetes or starvation. Mechanistically, ACOT12 and ACOT8 are dramatically upregulated in the liver to convert free fatty acid-derived acetyl-CoA to acetate and CoA. This conversion not only provides a large amount of acetate, which preferentially fuels the brain rather than muscle, but also recycles CoA, which is required for sustained fatty acid oxidation and ketogenesis. We suggest that acetate is an emerging novel 'ketone body' that may be used as a parameter to evaluate the progression of energy stress.
Topics: Humans; Animals; Mice; Acetyl Coenzyme A; Liver; Acetates; Brain; Fatty Acids, Nonesterified; Ketone Bodies; Starvation; Thiolester Hydrolases
PubMed: 37902629
DOI: 10.7554/eLife.87419