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European Journal of Pharmacology Apr 2024This study aimed to examine the therapeutic effects and response mechanisms of 4-OI in Alzheimer's disease (AD).
AIMS
This study aimed to examine the therapeutic effects and response mechanisms of 4-OI in Alzheimer's disease (AD).
METHODS
In this study, network pharmacology was employed to analyze potential targets for AD drug therapy. Immunofluorescence and quantitative reverse transcription polymerase chain reaction (qRT-PCR) techniques were utilized to detect inflammatory phenotypes in a 4-OI-resistant mouse microglia cell line (BV2). We conducted four classical behavioral experiments, namely the open field test, new object recognition test, Y maze test, and Morris water maze, to assess the emotional state and cognitive level of APPswe/PS1dE9 (referred to as APP/PS1) mice after 4-OI treatment. Hematoxylin and eosin (HE) staining, along with immunofluorescence staining, were performed to detect amyloid (Aβ) deposition in mouse brain tissue. To explore the potential molecular mechanisms regulating the effects of 4-OI treatment, we performed RNA-SEQ and transcription factor prediction analyses. Additionally, mouse BV2 cells underwent Western blotting analysis to elucidate potential molecular mechanisms underlying the observed effects.
RESULTS
We discovered that 4-OI exerts an inhibitory effect on neuroinflammation by promoting autophagy. This effect is attributed to the activation of the AMPK/mTOR/ULK1 pathway, achieved through enhanced phosphorylation of AMPK and ULK1, coupled with a reduction in mTOR phosphorylation. Furthermore, 4-OI significantly enhances neuronal recovery in the hippocampus and diminishes Aβ plaque deposition in APP/PS1 mice, improved anxiety in mice, and ultimately led to improved cognitive function.
CONCLUSIONS
Overall, the results of this study demonstrated that 4-OI improved cognitive deficits in AD mice, confirming the therapeutic effect of 4-OI on AD.
Topics: Mice; Animals; Alzheimer Disease; Mice, Transgenic; RNA-Seq; AMP-Activated Protein Kinases; TOR Serine-Threonine Kinases; Amyloid beta-Peptides; Disease Models, Animal; Amyloid beta-Protein Precursor; Succinates
PubMed: 38369275
DOI: 10.1016/j.ejphar.2024.176432 -
Cell Communication and Signaling : CCS Jan 2024As a dual-function metabolite, succinate has emerged in cell function and plays a key signaling role in linking mitochondrial function to other cellular functions....
BACKGROUND
As a dual-function metabolite, succinate has emerged in cell function and plays a key signaling role in linking mitochondrial function to other cellular functions. Succinate accumulation in the cytoplasm is commonly associated with hypoxia in the microenvironment and immune cell activation. Extracellular succinate released into the microenvironment is considered an inflammatory alarm that can be sensed by its membrane receptor SUCNR1, which boosts proinflammatory responses and acts akin to classical hormones and cytokines. Succinate plays an important role in the development of inflammatory diseases. Whether succinate facilitates the progression of endometriosis (EMs), characterized by chronic inflammation and peritoneal adhesion, is worth exploring.
OBJECTIVE
We mimicked the ectopic milieu in vitro and in vivo to evaluate the main source and potential role of succinate in endometriosis. We assessed the molecular and functional effects of succinate on macrophages and peritoneal mesothelial cells in peritoneal cavity. The effect of succinate/SUCNR1 signaling on ectopic endometrial stromal cells (ESCs) was further explored in this study.
METHODS
In this study, we used targeted organic acid metabolomics analysis and in vitro assays to assess the potential accumulation of succinate in the peritoneal fluid of EMs patients. We examined its correlation with disease severity, Visual Analogue Scale, and the Endometriosis Fertility Index. Flow cytometry, enzyme linked immunosorbent assay, western blot assay, quantitative real-time PCR, and other molecular biology techniques were used to explore the potential mechanisms.
RESULTS
By mimicking the ectopic milieu, we constructed an in vitro co-culture system and found that M1 polarized macrophages and that the peritoneal mesothelial cell line (HMrSV5) mainly released succinate into their microenvironment and activated the succinate receptor (SUCNR1) signal, which further polarized the macrophages and significantly enhanced the invasive survival of ESCs, and the adhesion to the peritoneum. We further investigated the pathological effects of extracellular succinate in vivo using a xenograft mouse models of endometriosis.
CONCLUSIONS
Succinate-SUCNR1 signaling facilitates the creation of inflammatory cells and plays a vital role in EMs progression and peritoneal adhesion. Our work on the molecular mechanisms underlying succinate accumulation and function will help elucidate the phenotypic mysteries of pain and infertility in EMs. Video Abstract.
Topics: Female; Humans; Animals; Mice; Succinic Acid; Endometriosis; Coculture Techniques; Succinates; Stromal Cells
PubMed: 38291428
DOI: 10.1186/s12964-023-01415-7 -
Gut Microbes 2024With an increasing interest in dietary fibers (DFs) to promote intestinal health and the growth of beneficial gut bacteria, there is a continued rise in the...
With an increasing interest in dietary fibers (DFs) to promote intestinal health and the growth of beneficial gut bacteria, there is a continued rise in the incorporation of refined DFs in processed foods. It is still unclear how refined fibers, such as guar gum, affect the gut microbiota activity and pathogenesis of inflammatory bowel disease (IBD). Our study elucidated the effect and underlying mechanisms of guar gum, a fermentable DF (FDF) commonly present in a wide range of processed foods, on colitis development. We report that guar gum containing diet (GuD) increased the susceptibility to colonic inflammation. Specifically, GuD-fed group exhibited severe colitis upon dextran sulfate sodium (DSS) administration, as evidenced by reduced body weight, diarrhea, rectal bleeding, and shortening of colon length compared to cellulose-fed control mice. Elevated levels of pro-inflammatory markers in both serum [serum amyloid A (SAA), lipocalin 2 (Lcn2)] and colon (Lcn2) and extensive disruption of colonic architecture further affirmed that GuD-fed group exhibited more severe colitis than control group upon DSS intervention. Amelioration of colitis in GuD-fed group pre-treated with antibiotics suggest a vital role of intestinal microbiota in GuD-mediated exacerbation of intestinal inflammation. Gut microbiota composition and metabolite analysis in fecal and cecal contents, respectively, revealed that guar gum primarily enriches Actinobacteriota, specifically . Guar gum also altered multiple genera belonging to phyla Bacteroidota and Firmicutes. Such shift in gut microbiota composition favored luminal accumulation of intermediary metabolites succinate and lactate in the GuD-fed mice. Colonic IL-18 and tight junction markers were also decreased in the GuD-fed group. Importantly, GuD-fed mice pre-treated with recombinant IL-18 displayed attenuated colitis. Collectively, unfavorable changes in gut microbiota activity leading to luminal accumulation of lactate and succinate, reduced colonic IL-18, and compromised gut barrier function following guar gum feeding contributed to increased colitis susceptibility.
Topics: Animals; Mice; Gastrointestinal Microbiome; Interleukin-18; Inflammation; Colitis; Dietary Fiber; Lactic Acid; Succinates; Galactans; Mannans; Plant Gums
PubMed: 38630030
DOI: 10.1080/19490976.2024.2341457 -
Journal of Medicinal Chemistry Jul 2023The succinate receptor (SUCNR1) has emerged as a potential target for the treatment of various metabolic and inflammatory diseases, including hypertension, inflammatory...
The succinate receptor (SUCNR1) has emerged as a potential target for the treatment of various metabolic and inflammatory diseases, including hypertension, inflammatory bowel disease, and rheumatoid arthritis. While several ligands for this receptor have been reported, species differences in pharmacology between human and rodent orthologs have limited the validation of SUCNR1's therapeutic potential. Here, we describe the development of the first potent fluorescent tool compounds for SUCNR1 and use these to define key differences in ligand binding to human and mouse SUCNR1. Starting from known agonist scaffolds, we developed a potent agonist tracer, TUG-2384 (), with affinity for both human and mouse SUCNR1. In addition, we developed a novel antagonist tracer, TUG-2465 (), which displayed high affinity for human SUCNR1. Using we demonstrate that three humanizing mutations on mouse SUCNR1, N18E, K269N, and G84W, are sufficient to restore high-affinity binding of SUCNR1 antagonists to the mouse receptor ortholog.
Topics: Mice; Humans; Animals; Succinic Acid; Receptors, G-Protein-Coupled; Coloring Agents
PubMed: 37318348
DOI: 10.1021/acs.jmedchem.3c00552 -
Journal of Vision Mar 2024Transmission and processing of sensory information in the visual system takes time. For motion perception, our brain can overcome this intrinsic neural delay through...
Transmission and processing of sensory information in the visual system takes time. For motion perception, our brain can overcome this intrinsic neural delay through extrapolation mechanisms and accurately predict the current position of a continuously moving object. But how does the system behave when the motion abruptly changes and the prediction becomes wrong? Here we address this question by studying the perceived position of a moving object with various abrupt motion changes by human observers. We developed a task in which a bar is monotonously moving horizontally, and then motion suddenly stops, reverses, or disappears-then-reverses around two vertical stationary reference lines. Our results showed that participants overestimated the position of the stopping bar but did not perceive an overshoot in the motion reversal condition. When a temporal gap was added at the reverse point, the perceptual overshoot of the end point scaled with the gap durations. Our model suggests that the overestimation of the object position when it disappears is not linear as a function of its speeds but gradually fades out. These results can thus be reconciled in a single process where there is an interplay of the cortical motion prediction mechanisms and the late sensory transient visual inputs.
Topics: Humans; Brain; Dioctyl Sulfosuccinic Acid; Motion; Motion Perception; Phenolphthalein
PubMed: 38512248
DOI: 10.1167/jov.24.3.6 -
Molecular Cell Mar 2024SUCNR1 is an auto- and paracrine sensor of the metabolic stress signal succinate. Using unsupervised molecular dynamics (MD) simulations (170.400 ns) and mutagenesis...
SUCNR1 is an auto- and paracrine sensor of the metabolic stress signal succinate. Using unsupervised molecular dynamics (MD) simulations (170.400 ns) and mutagenesis across human, mouse, and rat SUCNR1, we characterize how a five-arginine motif around the extracellular pole of TM-VI determines the initial capture of succinate in the extracellular vestibule (ECV) to either stay or move down to the orthosteric site. Metadynamics demonstrate low-energy succinate binding in both sites, with an energy barrier corresponding to an intermediate stage during which succinate, with an associated water cluster, unlocks the hydrogen-bond-stabilized conformationally constrained extracellular loop (ECL)-2b. Importantly, simultaneous binding of two succinate molecules through either a "sequential" or "bypassing" mode is a frequent endpoint. The mono-carboxylate NF-56-EJ40 antagonist enters SUCNR1 between TM-I and -II and does not unlock ECL-2b. It is proposed that occupancy of both high-affinity sites is required for selective activation of SUCNR1 by high local succinate concentrations.
Topics: Mice; Rats; Animals; Humans; Succinic Acid; Receptors, G-Protein-Coupled; Molecular Dynamics Simulation; Succinates; Stress, Physiological
PubMed: 38325379
DOI: 10.1016/j.molcel.2024.01.011 -
Journal of Applied Microbiology Nov 2023Microbial biocontrol agents have become an effective option to mitigate the harmfulness of chemical pesticides in recent years. This study demonstrates the control...
AIMS
Microbial biocontrol agents have become an effective option to mitigate the harmfulness of chemical pesticides in recent years. This study demonstrates the control efficacy of Bacillus velezensis CE 100 on the anthracnose causal agent, Colletotrichum gloeosporioides.
METHODS AND RESULTS
In vitro antifungal assays revealed that the culture filtrate and volatile organic compounds of B. velezensis CE 100 strongly restricted the mycelial development of C. gloeosporioides. Moreover, a bioactive compound, butyl succinate, was isolated from the n-butanol crude extract of B. velezensis CE 100 (bce), and identified by liquid chromatography-electrospray ionization hybrid ion-trap and time-of-flight mass spectrometry (LC-ESI-QTOF-MS) and one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR). Treatment with purified butyl succinate at a concentration of 300 μg mL-1 strongly controlled conidial germination of C. gloeosporioides with an inhibition rate of 98.66%, whereas butyl succinate at a concentration of 400 μg mL-1 showed weak antifungal action on the mycelial growth of C. gloeosporioides with an inhibition rate of 31.25%. Scanning electron microscopy revealed that the morphologies of butyl succinate-treated hyphae and conidia of C. gloeosporioides were severely deformed with shriveled and wrinkled surfaces. Furthermore, butyl succinate was able to control carbendazim-resistant C. gloeosporioides, demonstrating that it could be a promising agent for the suppression of other carbendazim-resistant fungal pathogens. An in vivo biocontrol assay demonstrated that the strain ce 100 broth culture and butyl succinate showed higher control efficacy on apple anthracnose than bce.
CONCLUSIONS
Our findings provide insight into the antifungal potential of B. velezensis ce 100 and its butyl succinate for efficient control of phytopathogenic fungi, such as C. gloeosporiodes, in plant disease protection. This is the first study to demonstrate the antifungal potential of bacteria-derived butyl succinate for control of C. gloeosporioides.
Topics: Antifungal Agents; Malus; Succinic Acid; Colletotrichum; Succinates; Plant Diseases
PubMed: 37903743
DOI: 10.1093/jambio/lxad247 -
Cell Death Discovery Dec 2023Cepharanthine (CEP), a bioactive compound derived from Stephania Cephalantha Hayata, is cytotoxic to various malignancies. However, the underlying mechanism of gastric...
Cepharanthine (CEP), a bioactive compound derived from Stephania Cephalantha Hayata, is cytotoxic to various malignancies. However, the underlying mechanism of gastric cancer is unknown. CEP inhibited the cellular activity of gastric cancer AGS, HGC27 and MFC cell lines in this study. CEP-induced apoptosis reduced Bcl-2 expression and increased cleaved caspase 3, cleaved caspase 9, Bax, and Bad expression. CEP caused a G2 cell cycle arrest and reduced cyclin D1 and cyclin-dependent kinases 2 (CDK2) expression. Meanwhile, it increased oxidative stress, decreased mitochondrial membrane potential, and enhanced reactive oxygen species (ROS) accumulation in gastric cancer cell lines. Mechanistically, CEP inhibited Kelch-like ECH-associated protein (Keap1) expression while activating NF-E2 related factor 2 (Nrf2) nuclear translocations, increasing transcription of Nrf2 target genes quinone oxidoreductase 1 (NQO1), heme oxygenase 1 (HMOX1), and glutamate-cysteine ligase modifier subunit (GCLM). Furthermore, a combined analysis of targeted energy metabolism and RNA sequencing revealed that CEP could alter the levels of metabolic substances such as D (+) - Glucose, D-Fructose 6-phosphate, citric acid, succinic acid, and pyruvic acid, thereby altering energy metabolism in AGS cells. In addition, CEP significantly inhibited tumor growth in MFC BALB/c nude mice in vivo, consistent with the in vitro findings. Overall, CEP can induce oxidative stress by regulating Nrf2/Keap1 and alter energy metabolism, resulting in anti-gastric cancer effects. Our findings suggest a potential application of CEP in gastric cancer treatment.
PubMed: 38086844
DOI: 10.1038/s41420-023-01752-z -
Bioresource Technology Sep 2023Microbial biomanufacturing is a promising approach to produce high-value compounds with low-carbon footprint and significant economic benefits. Among twelve "Top... (Review)
Review
Microbial biomanufacturing is a promising approach to produce high-value compounds with low-carbon footprint and significant economic benefits. Among twelve "Top Value-Added Chemicals from Biomass", itaconic acid (IA) stands out as a versatile platform chemical with numerous applications. IA is naturally produced by Aspergillus and Ustilago species through a cascade enzymatic reaction between aconitase (EC 4.2.1.3) and cis-aconitic acid decarboxylase (EC 4.1.1.6). Recently, non-native hosts such as Escherichia coli, Corynebacterium glutamicum, Saccharomyces cerevisiae, and Yarrowia lipolytica have been genetically engineered to produce IA through the introduction of key enzymes. This review provides an up-to-date summary of the progress made in IA bioproduction, from native to engineered hosts, covers in vivo and in vitro approaches, and highlights the prospects of combination tactics. Current challenges and recent endeavors are also addressed to envision comprehensive strategies for renewable IA production in the future towards sustainable development goals (SDGs).
Topics: Genetic Engineering; Aspergillus; Succinates; Saccharomyces cerevisiae; Metabolic Engineering
PubMed: 37290713
DOI: 10.1016/j.biortech.2023.129280 -
Human Genetics Dec 2023To investigate the genotype-to-protein-to-phenotype correlations of succinic semialdehyde dehydrogenase deficiency (SSADHD), an inherited metabolic disorder of...
To investigate the genotype-to-protein-to-phenotype correlations of succinic semialdehyde dehydrogenase deficiency (SSADHD), an inherited metabolic disorder of γ-aminobutyric acid catabolism. Bioinformatics and in silico mutagenesis analyses of ALDH5A1 variants were performed to evaluate their impact on protein stability, active site and co-factor binding domains, splicing, and homotetramer formation. Protein abnormalities were then correlated with a validated disease-specific clinical severity score and neurological, neuropsychological, biochemical, neuroimaging, and neurophysiological metrics. A total of 58 individuals (1:1 male/female ratio) were affected by 32 ALDH5A1 pathogenic variants, eight of which were novel. Compared to individuals with single homotetrameric or multiple homo and heterotetrameric proteins, those predicted not to synthesize any functional enzyme protein had significantly lower expression of ALDH5A1 (p = 0.001), worse overall clinical outcomes (p = 0.008) and specifically more severe cognitive deficits (p = 0.01), epilepsy (p = 0.04) and psychiatric morbidity (p = 0.04). Compared to individuals with predictions of having no protein or a protein impaired in catalytic functions, subjects whose proteins were predicted to be impaired in stability, folding, or oligomerization had a better overall clinical outcome (p = 0.02) and adaptive skills (p = 0.04). The quantity and type of enzyme proteins (no protein, single homotetramers, or multiple homo and heterotetramers), as well as their structural and functional impairments (catalytic or stability, folding, or oligomerization), contribute to phenotype severity in SSADHD. These findings are valuable for assessment of disease prognosis and management, including patient selection for gene replacement therapy. Furthermore, they provide a roadmap to determine genotype-to-protein-to-phenotype relationships in other autosomal recessive disorders.
Topics: Child; Humans; Male; Female; Amino Acid Metabolism, Inborn Errors; Developmental Disabilities; Phenotype; Succinate-Semialdehyde Dehydrogenase
PubMed: 37962671
DOI: 10.1007/s00439-023-02613-6