Search Results (180)

Acetone carboxylase (AC) from Xanthobacter autotrophicus is a 360 KDa α₂β₂γ₂ heterohexamer that catalyzes the ATP-dependent formation of phosphorylated acetone and bicarbonate intermediates that react at Mn(II) metal active sites to form acetoacetate. Structural models of X. autotrophicus AC (XaAC) with and without nucleotides reveal that the binding and phosphorylation of the two substrates occurs ~40 Å from the Mn(II) active sites where acetoacetate is formed. Based on the crystal structures, a significant conformational change was proposed to open and close a tunnel that facilitates the passage of reaction intermediates between the sites for nucleotide binding and phosphorylation of substrates and Mn(II) sites of acetoacetate formation. We have employed electron paramagnetic resonance (EPR), kinetic assays, and hydrogen/deuterium exchange mass spectrometry (HDX-MS) of poised ligand-bound states and site-specific amino acid variants to complete an in-depth analysis of Mn(II) coordination and allosteric communication throughout the catalytic cycle. In contrast with the established paradigms for carboxylation, our analyses of XaAC suggested a carboxylate shift that couples both local and long-range structural transitions. Shifts in the coordination mode of a single carboxylic acid residue (αE89) mediate both catalysis proximal to a Mn(II) center and communication with an ATP active site in a separate subunit of a 180 kDa α₂β₂γ₂ complex at a distance of 40 Å. This work demonstrates the power of combining structural models from X-ray crystallography with solution-phase spectroscopy and biophysical techniques to elucidate functional aspects of a multi-subunit enzyme. Full article

Investigating the functional interactions between rumen microbial fermentation and epithelial mitochondrial dynamics/energy metabolism in Tibetan sheep at different altitudes, this study examined ultrastructural changes in rumen epithelial tissues, expression levels of mitochondrial dynamics-related genes (fusion: Mfn1, Mfn2, OPA1, Mic60; fission: Drp1, Fis1, MFF), and ketogenesis pathway genes (HMGS2, HMGCL) in Tibetan sheep raised at three altitudes (TS 2500m, TS 3500m, TS 4500m). Correlation analysis was performed between rumen microbiota/metabolites and mitochondrial energy metabolism. Results: Ultrastructural variations were observed across altitudes. With increasing altitude, keratinized layer became more compact; desmosome connections between granular layer cells increased; mitochondrial quantity and distribution in spinous and basal layers increased. Mitochondrial dynamics regulation: Fission genes (FIS1, DRP1, MFF) showed significantly higher expression at TS 4500m (p < 0.01); fusion genes (Mfn1, OPA1) exhibited altitude-dependent upregulation. Energy metabolism markers: Pyruvate (PA) decreased significantly at TS 3500m/TS 4500m (p < 0.01); citrate (CA) increased with altitude; NAD⁺ peaked at TS 3500m but decreased significantly at TS 4500m (p < 0.01); Complex II (SDH) and Complex IV (CO) activities decreased at TS 4500m (p < 0.01). Ketogenesis pathway: β-hydroxybutyrate increased significantly with altitude (p < 0.01); acetoacetate peaked at TS 2500 m/TS 4500 m; HMGCS2 expression exceeded HMGCL, showing altitude-dependent upregulation at TS 4500m (p < 0.01). Microbiome–metabolism correlations: Butyrivibrio_2 and Fibrobacter negatively correlated with Mic60 (p < 0.01); Ruminococcaceae_NK4A214_Group positively correlated with Mfn1/OPA1 (p < 0.05); WGCNA identified 17 metabolite modules, with MEturquoise module positively correlated with DRP1/Mfn2/MFF (p < 0.05). Conclusion: Altitude-induced ultrastructural adaptations in rumen epithelium correlate with mitochondrial dynamics stability and ketogenesis upregulation. Mitochondrial fission predominates at extreme altitudes, while microbiota–metabolite interactions suggest compensatory energy regulation mechanisms. Full article

This study developed a novel water-soluble Cellulose Acetoacetate (CAA)-chitosan (CS) composite hydrogel drug delivery system. In this system, CAA and CS molecules are cross-linked via dynamic enamine bonds, forming a three-dimensional network structure suitable for drug encapsulation and controlled release. The primary objective was to address the challenges associated with the short half-life and significant fluctuations in therapeutic concentration of cytokine drugs, such as interleukin-2 (IL-2). A hydrogel system with a three-dimensional spatial network structure was successfully constructed via dynamic enamine bonds cross-linking between the acetoacetate groups in CAA molecules and the amino groups in CS. This system exhibits the following characteristics: (1) Dynamic covalent bonds impart adjustable mechanical properties to the hydrogel, enabling precise control over gelation time and mechanical performance; (2) A hierarchical pore structure (average pore size of 100–200 μm) provides a three-dimensional confined space for efficient drug encapsulation, achieving an IL-2 encapsulation efficiency of 83.3 ± 3.1%; (3) In vitro release studies demonstrated that the cumulative release of IL-2 within 72 h ranged from 18.4% to 34.7%, indicating sustained-release behavior. Cell viability assays confirmed that the hydrogel maintained the survival rate of L929 cells above 85% (as determined by the CCK-8 method), and live/dead staining revealed no apparent cytotoxicity. Overall, this three-dimensional network hydrogel based on dynamic covalent bonds represents a promising strategy for low-dose, long-lasting cytokine delivery. Full article

Background/Objectives: Ketone salt (KS) containing a racemic beta-hydroxybutyrate mixture is commonly used as an alternative fuel source as it may lead to improved health and/or performance. We postulate that KS will raise acetoacetate levels and represent the effectiveness of exogenous KS as an energy source. We conducted a pilot study to quantify changes in the circulating acetoacetate following KS and to determine if any changes in acetoacetate were associated with the changes in circulating beta-hydroxybutyrate. Methods: Thirteen adults (21.6 ± 4.3 years old; seven males/six females) completed this randomized, triple-blinded, placebo-controlled, cross-over design study. Participants consumed either KS or flavor-matched placebo with a one-week washout period between supplements. Blood samples were taken before and 30 min after consuming each supplement, and plasma acetoacetate and beta-hydroxybutyrate levels were measured by gas chromatography/mass spectrometry. Results: The consumption of KS resulted in a significant increase in acetoacetate from baseline. The increase in acetoacetate after the KS supplement was significantly greater than that following the consumption of a placebo (↑ 0.57 ± 0.44 mM vs. ↑ 0.07 ± 0.23 mM, p = 0.009, d = 0.86), and significantly and strongly related to the change in blood beta-hydroxybutyrate (r = 0.757, p < 0.001). Conclusions: Our findings indicate that KS markedly increases plasma ketone body interconversion, presumably to supply peripheral tissues for ATP generation. Full article

Polyhydroxyalkanoates (PHAs), as biosynthetic and biodegradable polymers, serve as alternatives to petroleum-based plastics, yet face critical cost barriers in large-scale production. While magnetic field (MF) stimulation enhances microbial activity, the optimal MF parameters and metabolic mechanisms for PHA biosynthesis remain unexplored. This study optimized magnetic field parameters to increase PHA biosynthesis in Haloferax mediterranei. A custom-engineered electromagnetic system identified 110 mT of static magnetic field (SMF) as the optimal level for biosynthesis, reaching 77.97 mg/(L·h) PHA volumetric productivity. A pulsed magnetic field caused oxidative stress and impaired substrate uptake despite increasing PHA synthesis. Prolonged SMF exposure (72 h) maximized PHA productivity, while 48 h of exposure attained 90% efficiency. Metabolomics revealed that SMF-driven carbon flux redirection via regulated butanoate metabolism led to a 2.10-fold increase in (R)-3-hydroxybutanoyl-CoA), while downregulating acetoacetate (0.51-fold) and suppressing PHA degradation (0.15-fold). This study pioneers the first application of metabolomics in archaea to decode SMF-induced metabolic rewiring in Haloferax mediterranei. Our findings establish SMF as a scalable bioenhancement tool, offering sustainable solutions for the circular bioeconomy. Full article

Introduction: Inhibiting cyclooxygenase-2 (COX-2) is a potential strategy in inflammation therapy. Thus, developing COX-2 inhibitors plays a pivotal role in efficient inflammation treatment. This study discloses the synthesis of new heterocyclic compounds incorporating pyridine, pyran, and/or pyrazole moieties as COX-2 inhibitors. Methods: In this study, the Claisen–Schmidt reaction of 1-(5-hydroxy-1,3-diphenyl-1H-pyrazol-4-yl)ethan-1-one 1 and p-methoxybenzaldehyde in ethanol containing aqueous sodium hydroxide (10%) led to the formation of 1-(5-hydroxy-1,3-diphenyl-1H-pyrazol-4-yl)-3-(4-methoxyphenyl)prop-2-en-1-one) 2. The latter compound was allowed to react as a key precursor with various nucleophiles such as ethyl cyanoacetate, malononitrile, cyclohexanone, ethyl acetoacetate, hydrazine, cyano acid hydrazide, hydrazide, and/or thiosemicarbazide to yield new heterocyclic derivatives comprising pyridine, pyran, and/or pyrazole moieties 3–15, according to the Michael addition reaction. The newly synthesized compounds were depicted using spectroscopic techniques such as IR, ¹H-NMR, ¹³C-NMR, and MS. Moreover, their anti-inflammatory efficiency was in vitro evaluated by means of protein denaturation inhibition and cell membrane protection assay. Results: The results of 2^−ΔΔct values of COX-2 expression for compounds 6, 11, 12, and 13 were 6.6, 2.9, 25.8, and 10.1, respectively. Therefore, compound 12, followed by 13, 11, and 6, showed potent anti-inflammatory properties by in vitro evaluation. Further, an in silico molecular docking study was performed on the best-docked compounds and reference drug (Diclofenac) to investigate their binding affinities against the active site of the target enzyme. The obtained results from the in silico study aligned with the biological evaluation. Conclusions: The studies open new doors for designing new heterocycles containing pyridine, pyran, and/or pyrazole moieties as potent anti-inflammatory agents. Full article

Purpose: Ketone bodies could be useful biomarkers in multiple sclerosis (MS) because the pathophysiological processes underlying MS disease progression induce metabolic stress. The purpose was to assess the relationships of ketone bodies with biomarkers of metabolic, inflammatory, and oxidative stress in MS. Methods: Blood samples and neurological assessments were obtained from 153 healthy controls (HC), 187 relapsing-remitting (RRMS), and 91 progressive MS (PMS) patients. AcAc, BHB, and acetone were measured using proton nuclear magnetic resonance spectroscopy. Indices of inflammatory vulnerability (IVX), metabolic malnutrition (MMX), and metabolic vulnerability (MVX) were computed from the NMR profiles. Cholesterol, apolipoprotein, lipid peroxidation, and antioxidant profiles were obtained. Regression analysis adjusted for age, sex, body mass index, and HC, RRMS, or PMS disease status. Results: AcAc and BHB levels were greater in MS compared to HC. BHB and ketone bodies were positively associated with disability on the MS Severity Scale and ambulation time. BHB was positively associated with IVX, MMX, and MVX. AcAc was positively associated with MMX and negatively associated with IVX and MVX. Total ketone body concentration was positively associated with MMX and MVX. BHB and AcAc levels were negatively associated with the amino acids alanine, valine, and leucine. Conclusions: Ketone bodies are associated with inflammatory vulnerability, metabolic vulnerability, and ambulatory disability measures in MS. Full article

Background: Hepatic fibrosis (HF) is a progressive liver disease characterized by the activation of hepatic stellate cells (HSCs) and changes in lipid metabolism. Abnormal ketone body (KD) levels, including acetoacetate (AcAc) and beta-hydroxybutyrate (BHB), have been observed in patients with HF, but the mechanisms linking ketone metabolism to fibrosis progression remain unclear. Objectives: This study aimed to investigate the role of AcAc in modulating HSCs activation and its potential mechanisms in HF. Methods: We examined the effects of AcAc on HSCs activation by Western blot analysis and RT-PCR both in vivo and in vitro. The impact of AcAc on lipid droplet accumulation in HSCs was assessed using total cholesterol (TC), triglyceride (TG), and Retinol (RET) kits, along with Nile Red and Oil Red O staining. RT-PCR screening was performed to analyze the expression of genes involved in lipid droplet formation and lipid metabolism. Results: Our findings show that AcAc inhibited HSCs activation by restoring LD levels. Peroxisome Proliferator-Activated Receptor Gamma (PPARγ) was identified as a key regulator through gene screening. AcAc primarily regulated PPARγ expression, and knocking down PPARγ significantly aggravated HF progression. Conclusions: The ability of AcAc to restore LD levels and regulate PPARγ suggests that it may represent a promising therapeutic strategy for HF by inhibiting HSCs activation. Full article

The total synthesis of biologically and pharmacologically important phenolic isoprenoids, grifolin and neogrifolin, was developed through simple allylation and cyclization procedures using only ethyl acetoacetate, ethyl crotonate, and farnesyl bromide as substrates. The regioisomeric terpenophenols, which consist solely of orcinol and farnesyl moieties, cannot be synthesized purely by direct coupling between the units. The regioselectivity issue was solved by controlling the timing of the allylation of β-ketoester with farnesyl bromide and the cyclization with ethyl crotonate. 2-Farnesyl-5-methyl-cyclohexane-1,3-dione and 6-farnesyl-5-methyl-cyclohexane-1,3-dione were prepared in a highly regioselective manner from ethyl acetoacetate in overall yields of 43% and 40%, respectively. The oxidative aromatization of the regioisomeric cyclohexane-1,3-diones produced grifolin and neogrifolin, respectively. Full article

Cardiovascular diseases (CVDs) persist as the primary cause of death worldwide, accounting for roughly 17.9 million fatalities each year. The prevalence of obesity, metabolic syndrome, and type 2 diabetes (key risk factors for CVD) continues to escalate at an alarming rate, necessitating novel therapeutic strategies to address this global health crisis. Nutritional ketosis, induced through ketogenic diets, modified fasting, intermittent fasting, and medium-chain triglyceride (MCT) oil consumption, has garnered attention for its potential cardioprotective effects. Ketosis is a metabolic state in which the body, due to a significantly reduced intake of carbohydrates, shifts its primary energy source from glucose to ketone bodies, i.e., beta-hydroxybutyrate (BHB), acetoacetate, and acetone, which are produced in the liver from fatty acids. This review examines the mechanisms by which ketone bodies, particularly BHB, mitigate cardiovascular risk. We focus mainly on the anti-inflammatory and antioxidative properties of BHB and summarize recent evidence to highlight the clinical relevance of ketosis in cardiometabolic health. Full article

The traditional liquid electrolytes pose safety hazards primarily attributed to the flammability of organic solvent, whereas solid-state electrolytes can significantly enhance the safety of lithium-ion batteries. Polymer solid electrolytes are being considered as an effective solution due to their excellent flexibility and low cost, but they suffer low ionic conductivity or high interface impedance. Here, the ketone-containing allyl acetoacetate monomers were polymerized within the cellulose membrane via UV photopolymerization to prepare a cellulose-supported poly-allyl acetoacetate polymer electrolyte. The PAAA electrolyte shows the ion conductivity of 1.14 × 10⁻⁴ S cm⁻¹ and the electrochemical stability window of 4.5 V. The Li symmetric battery can stably cycle for 1500 h at 0.1 mA cm⁻². The LiFeO₄‖Li cell achieves a discharge specific capacity of 160 mAh g⁻¹ and demonstrates excellent cycling stability. Matching with Ni-rich cathodes also delivers decent performance. The designed polymer electrolyte with high ionic conductivity offers new ideas and directions for the development of future energy storage technology. Full article

This study investigated the effects of a single dose of desvenlafaxine via oral administration on the pharmacokinetic parameters and clinical and laboratory characteristics in healthy volunteers using a pharmacometabolomics approach. In order to optimize desvenlafaxine’s therapeutic use and minimize potential adverse effects, this knowledge is essential. Methods: Thirty-five healthy volunteers were enrolled after a health trial and received a single dose of desvenlafaxine (Pristiq^®, 100 mg). First, liquid chromatography coupled to tandem mass spectrometry was used to determine the main pharmacokinetic parameters. Next, ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry was used to identify plasma metabolites with different relative abundances in the metabolome at pre-dose and when the desvenlafaxine peak plasma concentration was reached (pre-dose vs. post-dose). Results: Correlations were observed between metabolomic profiles, such as tyrosine, sphingosine 1-phosphate, and pharmacokinetic parameters, as well as acetoacetic acid and uridine diphosphate glucose associated with clinical characteristics. Our findings suggest that desvenlafaxine may have a broader effect than previously thought by acting on the proteins responsible for the transport of various molecules at the cellular level, such as the solute carrier SLC and adenosine triphosphate synthase binding cassette ABC transporters. Both of these molecules have been associated with PK parameters and adverse events in our study. Conclusions: This altered transporter activity may be related to the reported side effects of desvenlafaxine, such as changes in blood pressure and liver function. This finding may be part of the explanation as to why people respond differently to the drug. Full article

Background: Acute pancreatitis (AP) can be life-threatening with unpredictable severity. Despite advances in management, its pathogenesis remains unclear. This study investigated metabolites and lipoprotein profiles in AP patients of African descent to understand the underlying pathophysiological conditions so as to inform prognosis and management. Methods: Serum samples were collected from 9 healthy controls (HCs) and 30 AP patients (8 with mild AP, 14 with moderately severe AP, and 8 with severe AP) on days 1, 3, 5, and 7 post epigastric pain and subjected to nuclear magnetic resonance (NMR) spectroscopy. Wilcoxon and Kruskal–Wallis rank-sum tests compared numerical covariates. Lipoprotein characterization was performed using the Liposcale test, and Spearman’s rank test assessed data correlations. The p-values < 0.05 indicated significance. Results: Thirty-eight metabolic signals and information on lipoprotein subclasses were identified from the NMR spectra. The severity of AP correlated with increased levels of 3-hydroxybutyrate and acetoacetate and decreased levels of ascorbate. Distinct metabolic phenotypes were identified and characterized by unique inflammatory and lipoprotein profiles. High-density lipoprotein cholesterol (HDL-C) decreased across all the metabolic phenotypes of AP when compared with the HC, while elevated immediate density lipoprotein cholesterol (IDL-C) and very low-density lipoprotein cholesterol (VLDL-C) levels were observed. Time-dependent changes in metabolites were indicative of responsiveness to therapy. Conclusions: Our findings indicate that dysregulated metabolites and lipoproteins can be used to differentiate AP disease state and severity. Furthermore, integrating clinical parameters with data on metabolic and lipoprotein perturbations can contribute to a better understanding of the complex pathophysiology of AP. Full article

Background/Objectives: Elevating ketone levels with therapeutic nutritional ketosis can help to metabolically manage disease processes associated with epilepsy, diabetes, obesity, cancer, and neurodegenerative disease. Nutritional ketosis can be achieved with various dieting strategies such as the classical ketogenic diet, the modified Atkins diet, caloric restriction, periodic fasting, or the consumption of exogenous ketogenic supplements such as medium-chain triglycerides (MCTs). However, these various strategies can be unpleasant and difficult to follow, so that achieving and sustaining nutritional ketosis can be a major challenge. Thus, investigators continue to explore the science and applications of exogenous ketone supplementation as a means to further augment the therapeutic efficacy of this metabolic therapy. Methods: Here, we describe a structurally new synthetic triglyceride, glycerol tri-acetoacetate (Gly-3AcAc), that we prepared from glycerol and an acetoacetate precursor that produces hyperketonemia in the therapeutic range (2–3 mM) when administered to mice under both fasting and non-fasting conditions. Animal studies were undertaken to evaluate the potential effects of eliciting a ketogenic response systemically. Acute effects (24 h or less) were determined in male VM/Dk mice in both fasted and unfasted dietary states. Results: Concentration levels of β-hydroxybutyrate in blood were elevated (βHB; 2–3 mM) under both conditions. Levels of glucose were reduced only in the fasted state. No detrimental side effects were observed. Conclusions: Pending further study, this novel compound could potentially add to the repertoire of methods for inducing therapeutic nutritional ketosis. Full article

In this contribution, propylamine-functionalized cellulose (Cell-Pr-NH₂) was employed as the catalyst in the three-component reaction between hydroxylamine hydrochloride and various types of aryl/heteroaryl aldehydes, ethyl acetoacetate/ethyl 4-chloroacetoacetate, or ethyl 3-oxohexanoate. The result of these experiments was the formation of 3,4-disubstituted isoxazol-5(4H)-one heterocycles. The desired five-membered heterocyclic compounds were obtained in good to high yields at room temperature. The investigation of different solvents led us to the conclusion that water is the best solvent to perform the current one-pot, three-component reactions. Attempts to find the optimal catalyst loading clearly showed that 14 mg of cell-Pr-NH₂ seems to be sufficient to carry out the reactions. This method has highlighted some principles of green chemistry including less waste generation, atom economy, use of water as an environmentally friendly solvent, and energy saving. Purification without chromatographic methods, mild reaction conditions, simple work-up, low-cost reaction medium, saving time, and obtainable precursors are other notable features of this one-pot fashion. Full article