Search Results (881)

The cyclic AMP receptor protein (CRP) is a highly conserved global transcriptional regulator that integrates carbon metabolism and environmental adaptation in bacteria. However, its systematic role in the regulation of virulence in K. pneumoniae remains poorly understood; In this study, we constructed a crp deletion mutant (Δcrp) and a complemented strain (c-Δcrp) and employed a combination of in vitro virulence assays, in vivo infection models, transcriptomic profiling, and functional metabolic analyses to dissect the CRP-mediated metabolism–virulence regulatory axis; We show that crp deficiency does not significantly alter susceptibility to clinically relevant antibiotics but markedly impairs biofilm formation, motility, and host cell adhesion and invasion. In murine infection models, the Δcrp strain exhibits significantly reduced pulmonary colonization and lethality. Transcriptomic analysis reveals broad downregulation of phosphotransferase system (PTS)-associated genes, including srlA/srlB/srlE, mtlA and malX. Functional assays further demonstrate that crp loss severely compromises growth on multiple host-relevant carbon sources and is accompanied by aberrant accumulation of intracellular ATP and NADH, indicative of disrupted metabolic homeostasis; Collectively, these findings identify crp as an important regulator associated with PTS-mediated carbon metabolic balance, and virulence-related phenotypes in K. pneumoniae. Accordingly, targeting the CRP–PTS axis may offer a theoretical basis for metabolism-oriented anti-virulence interventions against K. pneumoniae by attenuating pathogenicity. Full article

N-Lactoyl-phenylalanine (Lac-Phe), identified in 2022 as an exercise-inducible signaling metabolite, is formed by carnosine dipeptidase 2 via conjugation of lactate and phenylalanine. Its circulating levels rise sharply after intense exercise in mice, humans, and racehorses, reflecting increased glycolytic flux. Beyond exercise, Lac-Phe also rises with feeding and metformin, positioning it as a potential integrator of energy intake, expenditure, and metabolic homeostasis. Centrally, Lac-Phe may contribute to appetite suppression by inhibiting hypothalamic orexigenic agouti-related protein neurons, primarily observed in obese rodent models, while sparing anorexigenic pro-opiomelanocortin neurons, thereby reducing food intake, promoting weight loss, and improving glucose tolerance in obese models without altering energy expenditure. Peripherally, it drives anti-inflammatory M2 macrophage polarization, ameliorating colitis and aiding recovery after spinal cord injury via NF-κB suppression and reactive oxygen species reduction. As a biomarker, Lac-Phe may offer advantages over lactate in reflecting mitochondrial dysfunction in conditions such as MELAS, sepsis, and NADH-reductive stress; however, these observations derive mainly from small-scale or exploratory studies and require prospective validation. Recent studies from 2024 to 2025 further reveal its partial and context-dependent role in mediating metformin’s effects, intensity- and sex-dependent responses, renal clearance via SLC17A1/3 transporters, and links to exercise-induced redox adaptations. The first human phase I trial (NCT06743009), launched in 2025, is assessing the metabolic effects of Lac-Phe in obesity. This Perspective summarizes Lac-Phe biosynthesis, physiological mechanisms, including its emerging but largely correlative connections to redox homeostasis, and therapeutic promise, underscoring its potential relevance for exercise-mimicking strategies in metabolic, inflammatory, and redox-related disorders. Full article

The fungal pathogen Candida albicans coordinated metabolism, organelle homeostasis, and stress responses for adapting to diverse host environments and maintaining virulence. While transcriptional control of these processes has been extensively studied, the contribution of post-transcriptional regulation remains incompletely understood. Here, we identify the P-body component Lsm1 as a critical factor of metabolic adaptation, mitochondrial homeostasis, and pathogenicity in C. albicans. Transcriptomic analysis revealed that loss of Lsm1 causes global transcriptional imbalance, leading to dysfunction of amino acid metabolism, mitochondrial function, endocytic trafficking, and autophagy processes. This dysfunction is accompanied by diminished TORC1 activity. Due to the aberrant TORC1 regulation caused by loss of Lsm1, ATG mRNA stability and autophagy flux was impaired under nutrient-rich condition and nitrogen starvation condition. In this context, the lsm1Δ/Δ cells established an adaptive metabolic and redox state characterized by altered NAD⁺/NADH and NADP⁺/NADPH balance, and enhanced antioxidant capacity. Moreover, the lsm1Δ/Δ cells displayed the defects in hyphal development, biofilm formation, and host cell interaction, and exhibited the attenuated virulence in a murine infection model. Together, our findings revealed that Lsm1-mediated post-transcriptional regulation is associated with the maintenance of amino acid metabolism, mitochondrial function, and TORC1 activity to fungal virulence, revealing a potential therapeutic target for C. albicans infections. Full article

Complex I (NADH:quinone oxidoreductase, CI) is central to cellular aerobic energy metabolism. The L-shaped structure of CI is unique, where the hydrophilic arm is responsible for the electron transfer function and the membrane arm operates proton pumping. These two functional sites are spatially far apart yet functionally connected. This basic core subunit architecture is highly conserved from bacterial to mammalian CI. Here, to gain detailed mechanistic insight into the role of the membrane subunit ND2 in the coupling mechanism, we mutated several highly conserved residues in the middle of the membrane axis of NuoN, the E. coli CI homolog of ND2. To more precisely investigate the consequences of mutational effects on highly conserved residues, we purified each mutant CI and compared the mutational effects on electron transfer and proton pumping activity using our instant membrane reconstitution method with E. coli double knockout (DKO) membrane vesicles lacking both CI and alternative NADH dehydrogenase (NDH-2). Thre results were corroborated by conventional proteoliposome reconstitution experiments. We found that Lys247 and Lys395 are absolutely essential for both electron transfer and proton pumping activities, while about 50% reduction of NADH oxidase activity but no reduction in proton pumping activity was observed in Lys217, and no significant decrease was detected in Glu133. Furthermore, unexpectedly, we were able to purify an NuoN knockout (ΔNuoN) mutant, which contained stoichiometric peripheral subunits NuoB, NuoCD, NuoE, NuoF, NuoG, and NuoI; and a substoichiometric amount of NuoH and a reduced amount of quinone. However, surprisingly, this isolated ΔNuoN CI showed CI activities (~30% of the WT) after being reconstituted into DKO membranes but not into proteoliposomes. Later, we confirmed by blue native PAGE that the wild-type CI was partially formed from ΔNuoN CI by recruiting its missing membrane subunits that existed in DKO membranes. Our data strongly suggest that ND2/NuoN plays an essential role in the coupling mechanism in CI. CI is the entry respiratory chain enzyme and is central to cellular energy metabolism. Two highly conserved lysine residues in the center of the antiporter-like membrane subunit ND2 are essential for the coupling mechanism between electron transfer and proton translocation. Full article

Background: Metabolic disorder-associated fatty liver disease (MASLD) is closely related to obesity and type 2 diabetes. Its pathogenesis involves many factors, including mitochondrial dysfunction, endoplasmic reticulum stress and intestinal flora disorders. Notoginsenoside R1 (NGR1) is a key bioactive component of Panax notoginseng. The purpose of this study was to investigate the therapeutic effect of notoginsenoside R1 (NGR1) on metabolic disorder-associated steatohepatitis (MASH) and its potential mechanism. Methods: Mice were fed a choline-deficient, L-amino acid-defined high-fat diet (CDAHFD) for 6 weeks and received NGR1 (50/100 mg/kg/day) in the last 3 weeks. The role of NGR1 was evaluated by developing metabolomics, proteomics and functional analysis. In addition, the effects of NGR1 on lipid droplet content, mitochondrial function and fatty acid oxidation in hepatocytes were also verified. Results: NGR1 improved MASH progression in CDAHFD-fed mice, significantly reduced liver triglyceride content from 31.2 ± 5.1 mmol/g to 20.5 ± 4.8 mg/g (p < 0.001), free fatty acid from 0.12 ± 0.03 mmol/g prot to 0.06 ± 0.028 mg/g (p < 0.001), TNF-α (p < 0.01), IL-1β (p < 0.001), α-SMA (p < 0.05) and Collagen1A1 levels (p < 0.01), as well as serum ALT and AST concentrations (p < 0.001), and alleviated hepatomegaly and lipid droplet accumulation. Metabolomics and proteomics analysis showed that NGR1 normalized liver metabolism in MASH mice and upregulated mitochondrial OXPHOS components, including NADH: ubiquinone oxidoreductase core subunit S2 (NDUFS2), and effectively reversed CDAHFD-induced mitochondrial dysfunction. Mitochondrial membrane potential and ATP production were restored. Conclusions: This study confirmed that NGR1 has significant therapeutic potential for MASH and improves mitochondrial function by upregulating NDUFS2. This study provides new insights for the future clinical treatment of MASH. Full article

Yeyong mustard is a mustard vegetable belonging to the Brassicaceae family and the Brassica genus. This study assembled, annotated, and analyzed the chloroplast genome of Brassica juncea L., aiming to clarify its systematic evolutionary relationship with other cruciferous plants. The study used the Illumina NovaSeq 6000 platform to sequence the entire chloroplast genome of leaf mustard, and systematically analyzed its genome structure, repeat sequences, nucleic acid diversity, and codon preferences using bioinformatics methods. At the same time, the phylogenetic relationships were constructed by combining the leaf chloroplast genome sequences of other cruciferous plants. The results showed that the chloroplast genome of leaf mustard had a total length of 153,490 bp and a GC content of 36.36%, exhibiting a typical tetrad structure; a total of 132 coding genes were annotated, including 87 mRNA genes, 37 tRNA genes, and eight rRNA genes, and no pseudogenes were found. Codon preference analysis shows that leucine (Leu) has the highest frequency of use, with 32 codons having a relative synonymous codon usage (RSCU) greater than 1, mostly ending in A or U; there are 37 scattered repetitive sequences and 315 simple repetitive sequences in the genome. Ka/Ks analysis showed that the chloroplast genes of leaf mustard were subjected to purification selection as a whole, while genes such as nadhF and petD showed positive selection, which is speculated to be related to adaptive evolution. The results of the phylogenetic analysis further confirm that the chloroplast genome of leaf mustard has a typical tetrad structure and is relatively conserved. It is most closely related to mustard greens in terms of evolutionary relationship, followed by Brassica plants such as nori and turnip, and is also closely related to Brassica plants such as European rapeseed. This study elucidated the conservative characteristics and evolutionary patterns of the chloroplast genome in mustard leaves, providing theoretical support for the phylogenetic research of the Brassicaceae family and the development and utilization of germplasm resources. Full article

Extracellular vesicles (EVs), particularly exosomes, have emerged as critical mediators of intercellular communication, yet the metabolite fraction of their cargo remains substantially underexplored relative to proteins and nucleic acids. This review synthesizes current knowledge on the exosomal metabolome as a functionally distinct intercellular signaling system with unique biophysical properties. We review the mechanisms proposed to govern metabolite encapsulation into exosomes, encompassing membrane transporter involvement, lipid raft partitioning, and binding to luminal proteins, and discuss the unresolved question of whether metabolite loading is selective or stochastic. Critically, we present a quantitative framework evaluating whether delivered metabolite quantities are sufficient to alter recipient cell metabolic pools, distinguishing receptor-mediated signaling from bulk substrate delivery. We also address methodological considerations including contamination artifacts and isolation-method biases that complicate interpretation of EV metabolomics data. Exosomal metabolites are reviewed across four functional categories: energy substrates (ATP, lactate, amino acids), signaling molecules (TCA cycle intermediates, eicosanoids, nucleotides), redox cofactors and antioxidants (NADH, glutathione), and oncometabolites. For each category, available evidence is critically appraised, distinguishing metabolites with direct mass spectrometric detection from those whose roles are inferred from parent-cell biology. The review examines the roles of exosomal metabolites in tumor-stroma metabolic symbiosis, immunometabolic regulation, inter-organ crosstalk in metabolic diseases including type 2 diabetes and non-alcoholic fatty liver disease, cancer metastasis, viral infections, and immune evasion. A quantitative framework is discussed to evaluate whether delivered metabolite quantities are sufficient to alter recipient cell metabolic pools, distinguishing receptor-mediated signaling from bulk substrate delivery. Technical challenges in exosomal metabolomics are reviewed, including the impact of isolation method on data quality, contamination artifacts, and current standardization gaps. Therapeutic implications of exosomal metabolite signaling are discussed, encompassing metabolite-loaded exosomes as therapeutic vehicles and exosomal metabolite loading as a pharmacological target. Integration of single-vesicle technologies with systems biology approaches is highlighted as a promising direction for advancing this field toward precision medicine applications in oncological and metabolic disorders. Full article

Cofactors are small molecules or ions that participate in enzymatic reactions as essential carriers of electrons, atoms, or functional groups, thereby governing cellular redox balance and energy metabolism. In the yeast Saccharomyces cerevisiae, the availability of cofactors such as NAD(H), NADP(H), CoA, and acetyl-CoA directly influences the flux through biosynthetic pathways leading to aroma-active compounds. Esters and higher alcohols are the two most important families of volatile flavor compounds in fermented alcoholic beverages. Their synthesis is intimately linked to the intracellular levels and ratios of these cofactors. This review summarizes recent progress in cofactor engineering strategies aimed at modulating the production of esters, higher alcohols, and 2,3-butanediol in S. cerevisiae. We discuss the underlying metabolic pathways, highlight key studies that manipulate cofactor pools to redirect carbon flux, and examine emerging tools (e.g., riboswitches, fine-tuned promoter systems) that enable precise cofactor balancing. Finally, we outline future challenges and opportunities for applying cofactor engineering to design yeast cell factories with tailored flavor profiles. Full article

Corydalis impatiens (Papaveraceae) is a traditional Tibetan medicinal plant (“Pa Xia Ga”) whose mitochondrial genome evolution remains unexplored, particularly in the context of high-altitude adaptation. This study presents the first complete mitochondrial genome sequence of an alpine Corydalis species to establish a comparative framework with the lowland congener C. pauciovulata for investigating environment-associated mitochondrial evolution. Using Illumina sequencing and reference-guided assembly, we characterized a 688,959 bp circular genome containing 74 genes, with GC content variations reflecting functional compartmentalization—elevated in structural RNA genes (tRNAs: 51.24%; rRNAs: 52.79%) versus protein-coding genes (44.19%). We identified 719 RNA editing sites concentrated in NADH dehydrogenase genes, suggesting post-transcriptional optimization of respiratory complex I under hypoxic conditions. The genome harbors 50 dispersed repeats (7.50%) and 67 SSRs with A-rich predominance, providing species-specific markers for authenticating “Pa Xia Ga” in Tibetan medicine quality control. Phylogenomic analysis confirms close affinity with C. pauciovulata while resolving intrageneral relationships within Ranunculales. These findings establish a dual-reference system for distinguishing conserved genus-level features from altitude-associated adaptations, enabling future comparative mitogenomics across the 465-species genus and supporting DNA-based medicinal plant identification. Full article

Background: In this study, we aimed to determine whether cold-water swimming could serve as a potential strategy to enhance antioxidant capacity, improve NADH utilization in oxidative metabolism, and consequently lead to better muscle metabolism and improved mitochondrial function in the skeletal muscles of rats. We hypothesized that cold-water swimming may upregulate malate–aspartate shuttle (MAS) expression, leading to more efficient NADH utilization in oxidative pathways and thereby improving muscle metabolism and mitochondrial function. Methods: We analyzed the expression of all MAS components, as well as the expression of phosphofructokinase I (PFK-1)—a key regulatory enzyme of glycolysis (which, under oxidative conditions, serves as a source of NADH for MAS)—in the skeletal muscles of rats subjected to cold-water swimming training. The study involved 32 male and 32 female rats aged 15 months, randomly assigned to control sedentary animals, animals training in cold water at 5 ± 2 °C, or animals training in water at thermal comfort temperature (36 ± 2 °C). The rats underwent swimming training for nine weeks, gradually increasing the duration of the sessions from 2 min to 4 min per day, five days a week. Results: Our findings revealed increased expression of all MAS enzymes involved in the delivery of NADH to mitochondria, elevated expression of the active form of PFK-1 indicating intensified glycolysis, increased reactive oxygen species (ROS) production, and upregulation of antioxidant enzymes. Conclusions: Cold-water swimming can improve metabolism and enhance mitochondrial function in the muscles of older adult rats subjected to cold-water swimming training. Full article

During the examination of a bicolor angelfish (Centropyge bicolor) imported from the Philippines and intended for sale on the Polish market, clinical signs of weakness and respiratory distress were observed. Mild hyperemia was noted along the lateral sides of the body and around the mouth. Necropsy revealed the presence of five orange-colored trematodes in the intestinal lumen, with an average body length of 3.12 mm. Based on morphological features and molecular analyses, the parasite was identified as Paragyiauchen sp. The following gene loci were amplified: the gene-encoding component of the large ribosomal subunit (28S rRNA), the gene-encoding NADH dehydrogenase subunit 1 (ND1), the gene cluster 5.8S rRNA-ITS2-28S rRNA and the gene cluster ITS2-28S rRNA. Bacterial species identification using MALDI-TOF MS revealed the presence of three species: Shewanella putrefaciens and Brevundimonas diminuta isolated from the head kidney, and Aeromonas caviae isolated from the liver. This study documents the first detection of representatives of Paragyliauchen genus in C. bicolor imported to Europe and highlights the potential risk of introducing new parasites and opportunistic bacterial pathogens through the ornamental fish trade. These findings emphasize the need for parasitological and microbiological screening of imported ornamental fish. Full article

Phospholipases A₂ (PLA₂s) are key mediators of the cytotoxic and inflammatory activities of snake venoms. While PLA₂ isoforms from Bothrops diporus venom have been characterized and shown to possess antimetastatic and antiangiogenic properties, their impact on mitochondrial bioenergetics and immune modulation has not yet been investigated. In this study, we examined the bioenergetic and immunomodulatory effects of B. diporus PLA₂s using integrated biochemical, metabolic, and multiplex cytokine analyses. In MDA-MB-231 breast cancer cells, pooled PLA₂s induced a dose-dependent decrease in MTT-reducing activity, increased mitochondrial ROS, caused Δψm hyperpolarization, and decreased NADH autofluorescence, collectively indicating sustained mitochondrial stress. Real-time impedance measurements further revealed a marked inhibition of cell proliferation. In human PBMCs, pooled PLA₂s elicited a dynamic cytokine program, inducing early cytotoxic (Granzyme B) and chemotactic (CCL2, CCL3, CCL4) mediators, followed by late pro-inflammatory and regulatory factors such as IL-6, TNF-β, IL-10 and IL-15. Analysis of a single purified PLA₂ isoform (Fraction 6) confirmed activation of the canonical IL-6/TNF-α/IL-1β axis but uniquely induced IL-10 and CCL20, revealing isoform-specific immunomodulatory properties. Altogether, these findings provide the first integrated characterization of mitochondrial and immune perturbations induced by B. diporus PLA₂s, expanding their recognized biological scope and underscoring their potential as molecular templates for novel pharmacological strategies targeting mitochondrial vulnerabilities or modulating the tumor immune microenvironment. Full article

Hypoxic pulmonary vasoconstriction (HPV) is a rapid and reversible constrictor response of the pulmonary vasculature, and especially its small muscular precapillary arteries, which is initiated by episodes of local alveolar hypoxia. Acting as a protective homeostatic vasomotor mechanism, HPV enables maximal gas exchange by diverting blood from poorly ventilated alveoli into those rich in oxygen, thereby optimizing oxygen uptake and the ventilation–perfusion (V/Q) ratio so as to maintain the arterial oxygen partial pressure (P_aO₂) within the physiological range. HPV is an intrinsic mechanism of pulmonary artery smooth muscle cells (PASMCs), and requires an O₂ sensor which acts through mediator(s) to trigger effector mechanisms within these cells to evoke constriction. Whereas HPV effector mechanisms are reasonably well defined, the nature of the O₂ sensor and mediators remains in dispute, and a number of proposals have been developed to account for these. Some (but not all) of these share a focus on the concept that hypoxia activates effector mechanisms by inducing a change in the PASMC cytoplasmic redox state. Of these, the Redox Theory, first proposed by Kenneth Weir and Stephen Archer in 1995, proposes that hypoxia inhibits mitochondrial production of reactive oxygen species (ROS), thereby causing the cytoplasm to become more reduced. This inhibits ongoing vasorelaxation maintained by the opening of voltage-gated K⁺ channels. In contrast, according to the Mitochondrial ROS hypothesis, introduced by Paul Schumacker and Naveen Chandel in 2001, hypoxia increases mitochondrial ROS production, causing an oxidizing shift in the cytoplasmic redox state that activates several vasoconstricting pathways. In a third redox-based scenario, developed by Michael Wolin and Sachin Gupte, hypoxia evokes contraction by causing a fall in H₂O₂ production by NADPH oxidase and by activating the pentose phosphate pathway. These effects inhibit basal vasorelaxation maintained by the guanylate cyclase and protein kinase G and also stimulate vasoconstricting mechanisms. In this comprehensive review, we first provide a detailed summary of the key studies contributing to the development of these proposals and then subject the evidence supporting them to a critical appraisal, based in part on how well they accord with the wider literature and recent developments in our understanding of how cells shape and deploy redox mechanisms in order to regulate cell function. Full article

Background: Skipper butterflies (Hesperiidae) are a morphologically distinctive lineage within Papilionoidea, yet relationships among many groups remain difficult to resolve, and mitochondrial genomic resources remain limited for some tribes, including Celaenorrhinini. Methods: We sequenced and characterized the complete mitochondrial genome of Celaenorrhinus victor using Illumina short-read sequencing. Gene content and organization were annotated, codon-usage patterns were assessed across Celaenorrhinus using relative synonymous codon usage and multiple compositional/selection tests (ENC–GC3s, neutrality, and PR2 analyses), selective constraints were evaluated using Ka/Ks for 13 protein-coding genes, and phylogenetic relationships were inferred with a partitioned maximum-likelihood analysis of 66 complete hesperiid mitogenomes. Results: The circular mitogenome of C. victor is 15,180 bp and contains the typical 37 genes (13 protein-coding genes, 22 tRNAs, and two rRNAs) plus an A + T-rich control region, with an overall A + T content of 79.64%. Gene order and orientation match those of other Celaenorrhinus and hesperiid mitogenomes. All protein-coding genes use standard invertebrate mitochondrial start codons (with cox1 initiating with TTG) and terminate with complete TAA stop codons. Codon usage is strongly biased toward A/U-ending codons and is broadly similar among five sampled Celaenorrhinus mitogenomes; ENC–GC3s, neutrality, and PR2 analyses indicate a predominant influence of A + T-directed mutational pressure with additional effects beyond base composition. Ka/Ks values for all 13 protein-coding genes were <1, consistent with pervasive purifying selection; cox genes were the most conserved, whereas several NADH dehydrogenase subunit genes evolved comparatively faster. The phylogeny recovered monophyletic Celaenorrhinini and a well-supported Celaenorrhinus clade, placing C. victor as sister to Celaenorrhinus consanguineus, while deeper nodes among major hesperiid lineages showed only moderate support in parts of the tree. Conclusions: This study provides a new mitogenomic resource for Celaenorrhinini and a comparative reference for codon usage and selective constraints within Celaenorrhinus, supporting the placement of C. victor within Hesperiidae while highlighting remaining uncertainty at deeper hesperiid divergences. Full article

Obesity is a complex metabolic disorder characterized by excessive accumulation of adipose tissue, resulting from an imbalance between energy intake and expenditure. It is associated with an increased risk of chronic diseases such as type 2 diabetes, cardiovascular disease, and cancer. Kefiran is a water-soluble exopolysaccharide produced by lactic acid bacteria, Lactobacillus kefiranofaciens, in kefir grains, composed primarily of glucose and galactose. It has garnered scientific interest due to its antioxidant, anti-inflammatory, and antimicrobial properties. Rice Kefiran (RK) is a functional food made with culturing L. kefiranofaciens in a medium containing rice. It is standardized to contain at least 5 mg/g of kefiran. This study investigated the anti-obesity effect of RK on a high-fat diet (HFD)-induced obese mouse model. HFD-fed mice exhibited marked increases in body weight gain (10.3 g vs. 2.0 g in controls) and adipose tissue mass (2.4 g vs. 0.4 g in controls). RK administration significantly attenuated weight gain to 8.3 g and 6.0 g at doses of 10 and 50 mg/kg, respectively, and reduced adipose tissue mass to 2.2 g (RK10) and 1.7 g (RK50). Oral glucose tolerance testing revealed impaired glucose clearance in HFD-fed mice, with blood glucose levels of 403.5 mg/dL at 15 min and 314.6 mg/dL at 120 min, compared with 348.8 mg/dL and 232.2 mg/dL in controls. RK treatment improved glucose tolerance, particularly at 50 mg/kg, reducing glucose levels to 359.0 mg/dL at 15 min and 263.8 mg/dL at 120 min. Biochemical analyses demonstrated that RK significantly reduced serum total cholesterol (213.6 mg/dL in HFD vs. 178.0 and 184.0 mg/dL in RK10 and RK50), triglycerides (379.0 mg/dL in HFD vs. 228.8 and 234.6 mg/dL), and non-esterified fatty acids (0.89 mEq/mL in HFD vs. 0.54 and 0.35 mEq/mL), while phospholipid levels remained unchanged. Furthermore, RK increased serum nicotinamide phosphoribosyltransferase (NAMPT) levels from 15.8 ng/mL in HFD-fed mice to 30.0 and 50.0 ng/mL in the RK10 and RK50 groups, respectively, and restored hepatic NAD⁺/NADH ratios toward control levels (1.78 µmol/L in HFD vs. 1.90 µmol/L and 2.07 µmol/L in RK10 and RK50). Gene expression analysis showed that RK increased Nampt mRNA expression and decreased the mRNA expression of adipogenic and lipogenic genes, including Srebp-1c, Acc-1, and Fas. These findings suggest that RK may ameliorate obesity-related metabolic disturbances and its associated metabolic dysfunctions by modulating lipid metabolism, glucose tolerance, and NAD⁺ biosynthesis pathways. Full article