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The ISME Journal Nov 2023Propionate is a key intermediate in anaerobic digestion processes and often accumulates in association with perturbations, such as elevated levels of ammonia. Under such...
Propionate is a key intermediate in anaerobic digestion processes and often accumulates in association with perturbations, such as elevated levels of ammonia. Under such conditions, syntrophic ammonia-tolerant microorganisms play a key role in propionate degradation. Despite their importance, little is known about these syntrophic microorganisms and their cross-species interactions. Here, we present metagenomes and metatranscriptomic data for novel thermophilic and ammonia-tolerant syntrophic bacteria and the partner methanogens enriched in propionate-fed reactors. A metagenome for a novel bacterium for which we propose the provisional name 'Candidatus Thermosyntrophopropionicum ammoniitolerans' was recovered, together with mapping of its highly expressed methylmalonyl-CoA pathway for syntrophic propionate degradation. Acetate was degraded by a novel thermophilic syntrophic acetate-oxidising candidate bacterium. Electron removal associated with syntrophic propionate and acetate oxidation was mediated by the hydrogen/formate-utilising methanogens Methanoculleus sp. and Methanothermobacter sp., with the latter observed to be critical for efficient propionate degradation. Similar dependence on Methanothermobacter was not seen for acetate degradation. Expression-based analyses indicated use of both H and formate for electron transfer, including cross-species reciprocation with sulphuric compounds and microbial nanotube-mediated interspecies interactions. Batch cultivation demonstrated degradation rates of up to 0.16 g propionate L day at hydrogen partial pressure 4-30 Pa and available energy was around -20 mol propionate. These observations outline the multiple syntrophic interactions required for propionate oxidation and represent a first step in increasing knowledge of acid accumulation in high-ammonia biogas production systems.
Topics: Propionates; Ammonia; Anaerobiosis; Bacteria; Acetates; Methanobacteriaceae; Euryarchaeota; Formates; Hydrogen; Methane
PubMed: 37679429
DOI: 10.1038/s41396-023-01504-y -
European Journal of Obstetrics,... Aug 2023Leiomyomas (fibroids), the most common benign solid tumours in females, originate from the myometrium and are associated with poor quality of life for patients. The... (Review)
Review
BACKGROUND
Leiomyomas (fibroids), the most common benign solid tumours in females, originate from the myometrium and are associated with poor quality of life for patients. The current management of uterine leiomyomas mainly includes surgical interventions such as hysterectomy and myomectomy, either by laparoscopy or laparotomy, which have several complications and are not ideal for preserving fertility. Therefore, there is a need to develop or repurpose medical treatments that do not require surgical intervention.
OBJECTIVE
Many drugs are used to treat the symptoms associated with uterine fibroids. The main objective of this systematic review is to give an up-to-date account of potential pharmacological agents (non-surgical methods) for the management of uterine leiomyomas.
SEARCH STRATEGY
PubMed was searched for scientific and clinical literature using the keyword 'uterine fibroids' along with the drug names described in each section. For example, 'uterine fibroids' and 'ulipristal acetate' were the keywords used to search for literature on ulipristal acetate (UPA).
RESULTS
Various preclinical and clinical studies have shown that some drugs and herbal formulations exhibit activity in the management of uterine leiomyomas. Recent studies found that drugs such as UPA, elagolix, EC313, asoprisnol, nutritional supplements and herbal preparations were helpful in treating the symptoms associated with uterine leiomyomas.
CONCLUSION
Many drugs show efficacy in patients with symptomatic uterine fibroids. UPA is one of the most studied and prescribed medicines for uterine fibroids; however, its usage has been restricted due to a few recent incidences of hepatic toxicity. Herbal drugs and natural supplements have also shown promising effects on uterine fibroids. The synergistic effects of nutritional and herbal supplements have been reported in certain cases, and should be studied in detail. Further research is warranted to identify the mode of action of the drugs, and to determine the precise conditions that would explain the causes of toxicity in some patients.
Topics: Female; Humans; Uterine Neoplasms; Quality of Life; Leiomyoma; Uterine Myomectomy; Acetates
PubMed: 37385088
DOI: 10.1016/j.ejogrb.2023.06.021 -
Talanta Dec 2023There is an increasing demand on alternatives methods to animal testing. Numerous health parameters have been already studied using in vitro devices able to mimic the...
There is an increasing demand on alternatives methods to animal testing. Numerous health parameters have been already studied using in vitro devices able to mimic the essential functions of the organs, being the real-time monitoring and response to stimuli their main limitations. Regarding the health of the gut, the short chain fatty acids, and particularly acetate, have emerged as key biomarkers to evaluate gut healthiness and disease development, although the number of acetate biosensors is still very low. This article presents a microbial biosensor based on fully biocompatible materials which is able to detect acetate in aerobic conditions in the range between 11 and 50 mM, and without compromising the viability and function of either bacteria (>90% viability) or mammalian cells (>80% viability). The detection mechanism is based on the metabolism of acetate by Escherichia coli bacteria immobilized on the transducer surface. Ferricyanide is used as a redox mediator to transfer electrons from the acetate metabolism in the bacterial cells to the transducer. High bacterial concentrations are immobilized in the transducer surface (10 cfu mL) by electrodeposition of conductive alginate hydrogels doped with reduced graphene oxide. The results show successful outcomes to exploit bacteria as a biosensing tool, based on the use of inkjet printed transducers, biocompatible materials and cell entrapment technologies.
Topics: Animals; Electrochemical Techniques; Hydrogels; Biocompatible Materials; Biosensing Techniques; Graphite; Acetates; Escherichia coli; Mammals
PubMed: 37453394
DOI: 10.1016/j.talanta.2023.124882 -
Pediatric Allergy and Immunology :... Sep 2023Broncho-Vaxom (BV) is known to attenuate allergic airway inflammation and chronic bronchitis in humans, but the underlying mechanism of this gut-mediated immunity...
PURPOSE
Broncho-Vaxom (BV) is known to attenuate allergic airway inflammation and chronic bronchitis in humans, but the underlying mechanism of this gut-mediated immunity remains unclear. This study investigated the effects of an oral BV on gut and systemic short-chain fatty acids (SCFAs) and immune responses.
METHODS
Oral BV was administered daily for 15 days prior to commencing the study in an asthma mouse model. Asthma was induced by ovalbumin (OVA) sensitization followed by a challenge with 1% OVA by inhalation. Asthmatic phenotypes, gut- and systemic- immune responses, and SCFAs in the cecum and blood were then investigated.
RESULTS
Airway hyperresponsiveness, total immunoglobulin E production, and pulmonary inflammation were all significantly suppressed by BV. The interleukin-13 level was also suppressed, whereas TGF-β expression was increased, in the lungs of the BV-treated mice. The regulatory T (Treg) cell numbers were increased in the small intestine, and the acetate level was increased in the cecum and serum after BV treatment. The levels of acetate in the cecum and serum were negatively correlated with airway hyperresponsiveness and with the eosinophil numbers in the BAL fluid of the OVA-induced mice. There was a positive correlation between the acetate levels in the feces and serum and the lung expression of TGF-β in the asthma mice.
CONCLUSIONS
Oral BV administration appears to prevent allergic inflammation by enhancing Treg cell proliferation and acetate production in an asthmatic mouse model.
Topics: Humans; Animals; Mice; Asthma; Acetates; Respiratory Hypersensitivity; Disease Models, Animal; Inflammation
PubMed: 37747743
DOI: 10.1111/pai.14018 -
Journal of Hematology & Oncology Feb 2024Emerging evidences suggest that aberrant metabolites contributes to the immunosuppressive microenvironment that leads to cancer immune evasion. Among tumor...
BACKGROUND
Emerging evidences suggest that aberrant metabolites contributes to the immunosuppressive microenvironment that leads to cancer immune evasion. Among tumor immunosuppressive cells, myeloid-derived suppressor cells (MDSCs) are pathologically activated and extremely immunosuppressive, which are closely associated with poor clinical outcomes of cancer patients. However, the correlation between MDSCs mediated immunosuppression and particular cancer metabolism remained elusive.
METHODS
Spontaneous lung adenocarcinoma and subcutaneous mouse tumor models, gas chromatography-mass spectrometry (GC-MS) and immunofluorescence assay of patient-derived lung adenocarcinoma tissues, and flow cytometry, RNA sequencing and Western blotting of immune cells, were utilized.
RESULTS
Metabolite profiling revealed a significant accumulation of acetic acids in tumor tissues from both patients and mouse model, which contribute to immune suppression and cancer progression significantly through free fatty acid receptor 2 (FFAR2). Furthermore, FFAR2 is highly expressed in the myeloid-derived suppressor cells (MDSCs) from the tumor of lung adenocarcinoma (LUAD) patients which is greatly associated with poor prognosis. Surprisingly, whole or myeloid Ffar2 gene deletion markedly inhibited urethane-induced lung carcinogenesis and syngeneic tumor growth with reduced MDSCs and increased CD8 T cell infiltration. Mechanistically, FFAR2 deficiency in MDSCs significantly reduced the expression of Arg1 through Gαq/Calcium/PPAR-γ axis, which eliminated T cell dysfunction through relieving L-Arginine consumption in tumor microenvironment. Therefore, replenishment of L-Arginine or inhibition to PPAR-γ restored acetic acids/FFAR2 mediated suppression to T cells significantly. Finally, FFAR2 inhibition overcame resistance to immune checkpoint blockade through enhancing the recruitment and cytotoxicity of tumor-infiltrating T cells.
CONCLUSION
Altogether, our results demonstrate that the acetic acids/FFAR2 axis enhances MDSCs mediated immunosuppression through Gαq/calcium/PPAR-γ/Arg1 signaling pathway, thus contributing to cancer progression. Therefore, FFAR2 may serve as a potential new target to eliminate pathologically activated MDSCs and reverse immunosuppressive tumor microenvironment, which has great potential in improving clinical outcomes of cancer immunotherapy.
Topics: Humans; Mice; Animals; Myeloid-Derived Suppressor Cells; Calcium; Peroxisome Proliferator-Activated Receptors; Neoplasms; Adenocarcinoma of Lung; Arginine; Acetates; Tumor Microenvironment
PubMed: 38402237
DOI: 10.1186/s13045-024-01529-6 -
Nutrients Aug 2023Acetate is associated with adipocyte differentiation and lipid deposition. To further develop this scientific point, obese mice on a high-fat diet were given an...
Acetate is associated with adipocyte differentiation and lipid deposition. To further develop this scientific point, obese mice on a high-fat diet were given an intragastric administration of acetate for 8 weeks and mouse adipose mesenchymal stem cells (mAMSCs) were treated with acetate for 24 h. The results showed that the body weight, food intake, Lee's index, adipose tissue coefficient, liver index, blood lipid levels, insulin resistance, pro-inflammatory factors levels and fatty lesions in liver and adipose tissue in obese mice treated with acetate increased markedly, while anti-inflammatory factors levels and liver function decreased significantly ( < 0.05). The mRNA expression levels of PPAR-γ, C/EBP-α, SREBP, AFABP, FAS, ACC-1, SCD-1, LPL, LEPR, GPR41 and GPR43 genes in adipose tissue and mAMSCs were significantly increased, while the mRNA expression levels of HSL, CPT-1, CPT-2, AMPK, AdipoR1 and AdipoR2 genes were significantly reduced ( < 0.05). Except for AMPK-α signaling pathway proteins, the phosphorylation levels of p38 MAPK, ERK1/2, JNK and mTOR were significantly increased ( < 0.05) and these changes were dose-dependent. The findings indicated that acetate played a positive role in regulating adipocyte differentiation and lipid deposition by activating MAPKs and mTOR signaling pathways (the expression up-regulation of genes such as PPAR-γ, C/EBP-α and SREBP-1, etc.) and inhibiting the AMPK signaling pathway (the expression down-regulation of genes such as HSL, CPT-1 and AMPK-α, etc.).
Topics: Animals; Mice; Mice, Obese; AMP-Activated Protein Kinases; Peroxisome Proliferator-Activated Receptors; Sterol Regulatory Element Binding Protein 1; Acetates; Cell Differentiation; CCAAT-Enhancer-Binding Protein-alpha; Carnitine O-Palmitoyltransferase; Adipocytes; RNA, Messenger
PubMed: 37686768
DOI: 10.3390/nu15173736 -
Nano Letters Jul 2023As a ROS scavenger, resveratrol exerts a neuroprotective effect by polarizing the M1 microglia to the anti-inflammatory M2 phenotype for ischemic stroke treatment....
As a ROS scavenger, resveratrol exerts a neuroprotective effect by polarizing the M1 microglia to the anti-inflammatory M2 phenotype for ischemic stroke treatment. However, the obstruction of the blood-brain barrier (BBB) seriously impairs the efficacy of resveratrol. Herein, we develop a stepwise targeting nanoplatform for enhanced ischemic stroke therapy, which is fabricated by pH-responsive poly(ethylene glycol)-acetal-polycaprolactone-poly(ethylene glycol) (PEG-Acetal-PCL-PEG) and modified with cRGD and triphenylphosphine (TPP) on a long PEG chain and a short PEG chain, respectively. The as-designed micelle system features effective BBB penetration through cRGD-mediated transcytosis. Once entering the ischemic brain tissues and endocytosed by microglia, the long PEG shell can be detached from the micelles in the acidic lysosomes, subsequently exposing TPP to target mitochondria. Thus, the micelles can effectively alleviate oxidative stress and inflammation by enhanced delivery of resveratrol to microglia mitochondria, reversing the microglia phenotype through the scavenging of ROS. This work offers a promising strategy to treat ischemia-reperfusion injury.
Topics: Humans; Micelles; Ischemic Stroke; Reactive Oxygen Species; Acetals; Resveratrol; Polymers; Polyethylene Glycols; Oxidative Stress; Inflammation
PubMed: 37401457
DOI: 10.1021/acs.nanolett.3c01567 -
Islets Dec 2024Studies suggest that short chain fatty acids (SCFAs), which are primarily produced from fermentation of fiber, regulate insulin secretion through free fatty acid...
BACKGROUND
Studies suggest that short chain fatty acids (SCFAs), which are primarily produced from fermentation of fiber, regulate insulin secretion through free fatty acid receptors 2 and 3 (FFA2 and FFA3). As these are G-protein coupled receptors (GPCRs), they have potential therapeutic value as targets for treating type 2 diabetes (T2D). The exact mechanism by which these receptors regulate insulin secretion and other aspects of pancreatic β cell function is unclear. It has been reported that glucose-dependent release of acetate from pancreatic β cells negatively regulates glucose stimulated insulin secretion. While these data raise the possibility of acetate's potential autocrine action on these receptors, these findings have not been independently confirmed, and multiple concerns exist with this observation, particularly the lack of specificity and precision of the acetate detection methodology used.
METHODS
Using Min6 cells and mouse islets, we assessed acetate and pyruvate production and secretion in response to different glucose concentrations, via liquid chromatography mass spectrometry.
RESULTS
Using Min6 cells and mouse islets, we showed that both intracellular pyruvate and acetate increased with high glucose conditions; however, intracellular acetate level increased only slightly and exclusively in Min6 cells but not in the islets. Further, extracellular acetate levels were not affected by the concentration of glucose in the incubation medium of either Min6 cells or islets.
CONCLUSIONS
Our findings do not substantiate the glucose-dependent release of acetate from pancreatic β cells, and therefore, invalidate the possibility of an autocrine inhibitory effect on glucose stimulated insulin secretion.
Topics: Animals; Mice; Insulin-Secreting Cells; Diabetes Mellitus, Type 2; Acetates; Glucose; Pyruvic Acid
PubMed: 38607959
DOI: 10.1080/19382014.2024.2339558 -
Communications Biology Oct 2023Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease. Ethanol consumption has been reported to reduce morbidity in RA patients, but the mechanism behind it...
Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease. Ethanol consumption has been reported to reduce morbidity in RA patients, but the mechanism behind it remains unclear. Our results showed that Muribaculaceae was predominant in the gut microbiota of mice after ethanol treatment, and the levels of microbiota metabolite acetate were increased. Acetate reduced arthritis severity in collagen-induced arthritis (CIA) mice, which was associated with a decrease in the articular neutrophils and the myeloperoxidase-deoxyribonucleic acid complex in serum. Meanwhile, in vitro experiments confirmed that acetate affected neutrophil activity by acting on G-protein-coupled receptor 43, which reduced endoplasmic reticulum stress in neutrophils and inhibited neutrophil extracellular traps formation. Furthermore, exogenous acetate reversed CIA mice with exacerbated gut microbial disruption, further confirming that the effect of gut microbial metabolite acetate on neutrophils in vivo is crucial for the immune regulation. Our findings illuminate the metabolic and cellular mechanisms of the gut-joint axis in the regulation of autoimmune arthritis, and may offer alternative avenues to replicate or induce the joint-protective benefits of ethanol without associated detrimental effects.
Topics: Humans; Mice; Animals; Extracellular Traps; Arthritis, Rheumatoid; Neutrophils; Arthritis, Experimental; Acetates
PubMed: 37884797
DOI: 10.1038/s42003-023-05473-y -
Emerging Topics in Life Sciences Feb 2024Short-chain fatty acids are known modulators of host-microbe interactions and can affect human health, inflammation, and outcomes of microbial infections. Acetate is the... (Review)
Review
Short-chain fatty acids are known modulators of host-microbe interactions and can affect human health, inflammation, and outcomes of microbial infections. Acetate is the most abundant but least well-studied of these modulators, with most studies focusing on propionate and butyrate, which are considered to be more potent. In this mini-review, we summarize current knowledge of acetate as an important anti-inflammatory modulator of interactions between hosts and microorganisms. This includes a summary of the pathways by which acetate is metabolized by bacteria and human cells, the functions of acetate in bacterial cells, and the impact that microbially derived acetate has on human immune function.
Topics: Humans; Fatty Acids, Volatile; Propionates; Acetates; Butyrates; Bacteria
PubMed: 36945843
DOI: 10.1042/ETLS20220092