Acid Oxidation Pathway Research Articles

The immune mechanism of the mTOR/ACC1/CPT1A fatty acid oxidation signaling pathway in Hashimoto's thyroiditis.

Hashimoto's thyroiditis (HT) is the most common autoimmune thyroid disease (AITD), which is distinguished by high thyroid peroxidase antibody (TPOAb) or thyroglobulin antibody (TgAb). The differentiation of CD4+T cell subsets in patients with HT is imbalanced, with Treg cells decreased and Th17 cells abnormally activated. Fatty acid oxidation supports the differentiation of Th17 cells and induces inflammation, but the specific mechanism is still unknown. This study aimed to explore the role of fatty acid oxidation and its pathway in the pathogenesis of autoimmune thyroiditis and the immune mechanism. In in vitro experiments, a total of 60 HT patients and 20 healthy controls were selected and their CD4+T cells were sorted by magnetic beads. All 80 samples were divided into 4 groups on average: HC group (Healthy control group), HT group (Hashimoto thyroiditis CD4+T cell inactive group), TCC group(Hashimoto thyroiditis CD4+T cell activation), TCC + ETO group(Hashimoto thyroiditis CD4+T cell activation + Etomoxir group). In in vivo experiments, the mice were randomly divided into 3 groups: Con group(Control group), mTg group (CBA/J mice were injected with mTg for modeling, that is EAT mice group), and mTg + ETO group (Etomoxir intervention in EAT mice group). Fatty acid oxidation substrates of CD4+T cells in human peripheral blood were detected by targeted metabolomics. The expressions of key fatty acid oxidation proteins mTOR, ACC1 and CPT1A were detected by Western blotting. The proportion of CD4+T cell subtype differentiation in human and mouse models was detected by flow cytometry. The severity of EAT was detected by HE staining. Compared with healthy controls, the level of CPT1A in CD4+T cells of HT patients was increased, and the intracellular fatty acid content was significantly decreased, indicating that the level of fatty acid oxidation was enhanced in HT patients. After adding Etomoxir, the level of fatty acid oxidation was significantly inhibited, and the imbalance of CD4+T cell subpopulation differentiation in HT patients was reversed. In EAT mice, the mTOR/ACC1/CPT1A pathway was significantly activated, and its expression level was decreased after adding Etomoxir. At the same time, Etomoxir could reverse the reprogramming of abnormal metabolism in EAT mice cells, reduce the spleen index, and improve lymphocyte infiltration in the thyroid. The mTOR/ACC1/CPT1A fatty acid oxidation pathway of CD4+T cells in Hashimoto's thyroiditis was increased, and treatment with Etomoxir could inhibit the activation of this pathway, and reverse the reprogramming of abnormal metabolism in CD4+T cells, thereby reducing Hashimoto's thyroiditis.

13C Stable Isotope Tracing Reveals Distinct Fatty Acid Oxidation Pathways in Proliferative vs. Oxidative Cells.

The TCA cycle serves as a central hub to balance catabolic and anabolic needs of the cell, where carbon moieties can either contribute to oxidative metabolism or support biosynthetic reactions. This differential TCA cycle engagement for glucose-derived carbon has been extensively studied in cultured cells, but the fate of fatty acid (FA)-derived carbons is poorly understood. To fill the knowledge gap, we have developed a strategy to culture cells with long-chain FAs without altering cell viability. By tracing 13C-FA we show that FA oxidation (FAO) is robust in both proliferating and oxidative cells while the metabolic pathway after citrate formation is distinct. In proliferating cells, a significant portion of carbon derived from FAO exits canonical TCA cycle as citrate and converts to unlabeled malate in cytosol. Increasing FA supply or b-oxidation does not change the partition of FA-derived carbon between cytosol and mitochondria. Oxidation of glucose competes with FA derived carbon for the canonical TCA pathway thus promoting FA carbon flowing into the alternative TCA pathway. Moreover, the coupling between FAO and the canonical TCA pathway changes with the state of oxidative energy metabolism.

Pea Albumin Alleviates Oleic Acid-Induced Lipid Accumulation in LO2 Cells Through Modulating Lipid Metabolism and Fatty Acid Oxidation Pathways.

Excessive lipid accumulation in the liver can cause NAFLD, leading to chronic liver injury. To relieve liver lipid accumulation by dietary proteins, this study used oleic acid (OA) induction to establish a stable in vitro LO2 cell lipid accumulation model. This model was used to explore the mechanism by which pea albumin (PA) regulates lipid levels in LO2 cells. PA has been shown to ameliorate OA-induced lipid accumulation in LO2 cells by reducing the aggregation of intracellular lipid droplets and lowering cell TG and TC levels. In addition, it can alleviate OA-induced LO2 cell damage and oxidative stress, reduce cellular ALT and AST secretion, lower cellular MDA levels, and increase GSH-Px viability. Regulation of lipid metabolism in LO2 cells involves inhibiting the cellular lipid synthesis pathway and activating the expression of proteins related to the triglyceride catabolic and fatty acid oxidation pathways. PA contributes to regulating lipid accumulation in LO2 cells. This study provides new insights into alleviating liver fat accumulation and a theoretical basis for exploring the mechanism of protein regulation of liver cell lipid metabolism.

Knockdown of ketohexokinase versus inhibition of its kinase activity exert divergent effects on fructose metabolism.

Excessive fructose intake is a risk factor for the development of obesity and its complications. Targeting ketohexokinase (KHK), the first enzyme of fructose metabolism, has been investigated for the management of metabolic dysfunction-associated steatotic liver disease (MASLD). We compared the effects of systemic, small molecule inhibitor of KHK enzymatic activity with hepatocyte-specific, N-acetylgalactosamine siRNA-mediated knockdown of KHK in mice on an HFD. We measured KHK enzymatic activity, extensively quantified glycogen accumulation, performed RNA-Seq analysis, and enumerated hepatic metabolites using mass spectrometry. Both KHK siRNA and KHK inhibitor led to an improvement in liver steatosis; however, via substantially different mechanisms, KHK knockdown decreased the de novo lipogenesis pathway, whereas the inhibitor increased the fatty acid oxidation pathway. Moreover, KHK knockdown completely prevented hepatic fructolysis and improved glucose tolerance. Conversely, the KHK inhibitor only partially reduced fructolysis, but it also targeted triokinase, mediating the third step of fructolysis. This led to the accumulation of fructose-1 phosphate, resulting in glycogen accumulation, hepatomegaly, and impaired glucose tolerance. Overexpression of wild-type, but not kinase-dead, KHK in cultured hepatocytes increased hepatocyte injury and glycogen accumulation after treatment with fructose. The differences between KHK inhibition and knockdown are, in part, explained by the kinase-dependent and -independent effects of KHK on hepatic metabolism.

Overexpression of CPT1A disrupts the maintenance and regenerative function of muscle stem cells.

The skeletal muscle satellite cells (SCs) mediate regeneration of myofibers upon injury. As they switch from maintenance (quiescence) to regeneration, their relative reliance on glucose and fatty acid metabolism alters. To explore the contribution of mitochondrial fatty acid oxidation (FAO) pathway to SCs and myogenesis, we examined the role of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme of FAO. CPT1A is highly expressed in quiescent SCs (QSCs) compared with activated and proliferating SCs, and its expression level decreases during myogenic differentiation. Myod1Cre-driven overexpression (OE) of Cpt1a in embryonic myoblasts (Cpt1aMTG) reduces muscle weight, grip strength, and contractile force without affecting treadmill endurance of adult mice. Adult Cpt1aMTG mice have reduced number of SC, impairing muscle regeneration and promoting lipid infiltration. Similarly, Pax7CreER-driven, tamoxifen-inducible Cpt1a-OE in QSCs of adult muscles (Cpt1aPTG) leads to depletion of SCs and compromises muscle regeneration. The reduced proliferation of Cpt1a-OE SCs is associated with elevated level of acyl-carnitine, and acyl-carnitine treatment impedes proliferation of wildtype SCs. These findings indicate that aberrant level of CPT1A elevates acyl-carnitine to impair the maintenance, proliferation and regenerative function of SCs.

Low doses of acetyl trihexyl citrate plasticizer promote adipogenesis in hepatocytes and mice.

Accumulating epidemiological evidence underscores the association between pervasive environmental factors and an increased risk of metabolic diseases. Environmental chemicals, recognized disruptors of endocrine and metabolic processes, may contribute to the global prevalence of metabolic disorders, including obesity. Acetyl tributyl citrate (ATHC), categorized as a citric acid ester plasticizer, serves as a substitute for di-(2-ethylhexyl) phthalate (DEHP) in various everyday products. Despite its widespread use and the increasing risk of exposure in humans and animals due to its high leakage rates, information regarding the safety of exposure to environmentally relevant doses of ATHC remains limited. This study aimed to investigate the potential impact of ATHC exposure on metabolic homeostasis. Both in vivo and in vitro exposure models were used to characterize the effects induced by ATHC exposure. C57BL/6J male mice were subjected to a diet containing ATHC for 12weeks, and metabolism-related parameters were monitored and analyzed throughout and after the exposure period. Results indicated that sub-chronic dietary exposure to ATHC induced an increase in body fat percentage, elevated serum lipid levels, and increased lipid content in the liver tissue of mice. Furthermore, the effect of ATHC exposure on murine hepatocytes were examined and results indicated that ATHC significantly augmented lipid levels in AML12 hepatocytes, disrupting energy homeostasis and altering the expression of genes associated with fatty acid synthesis, uptake, oxidation, and secretion pathways. Conclusively, both in vivo and in vitro results suggest that exposure to low levels of ATHC may be linked to an elevated risk of obesity and fatty liver in mice. The potential implications of ATHC on human health warrant comprehensive evaluation in future studies.

Dapagliflozin attenuates AKI to CKD transition in diabetes by activating SIRT3/PGC1-α signaling and alleviating aberrant metabolic reprogramming

BackgroundPatients with diabetes are prone to acute kidney injury (AKI) with a high mortality rate, poor prognosis, and a higher risk of progression to chronic kidney disease than non-diabetic patients. MethodsStreptozotocin (STZ)-treated type 1 and db/db type 2 diabetes model were established, AKI model was induced in mice by ischemia-reperfusion injury(IRI). Mouse proximal tubular cell cells were subjected to high glucose and hypoxia-reoxygenation in vitro. Transcriptional RNA sequencing was performed for clustering analysis and target gene screening. Renal structural damage was determined by histological staining, whereas creatinine and urea nitrogen levels were used to measure renal function. ResultsDeteriorated renal function and renal tissue damage were observed in AKI mice with diabetic background. RNA sequencing showed a decrease in fatty acid oxidation (FAO) pathway and an increase in abnormal glycolysis. Treatment with Dapa, Sitagliptin(a DPP-4 inhibitor)and insulin reduced blood glucose levels in mice, and improved renal function. However, Dapa had a superior therapeutic effect and alleviated aberrant FAO and glycosis. Dapa reduced cellular death in cultured cells under high glucose hypoxia-reoxygenation conditions, alleviated FAO dysfunction, and reduced abnormal glycolysis. RNA sequencing showed that SIRT3 expression was reduced in diabetic IRI, which was largely restored by Dapa intervention. 3-TYP, a SIRT3 inhibitor, reversed the renal protective effects of Dapa and mediated abnormal FAO and glycolysis in mice and tubular cells. ConclusionOur study provides experimental evidence for the use of Dapa as a means to reduce diabetic AKI by ameliorating metabolic reprogramming in renal tubular cells.

HAO2 protects from proximal tubular cells injured in rats with chronic kidney disease by promoting fatty acid metabolic processes

The complex pathogenesis of kidney disease is closely related to the diversity of kidney intrinsic cells. In this study, single-cell transcriptome sequencing technology was used to sequence and analyze blood and kidney tissue cells in normal control rats and rats with chronic kidney disease (CKD), focusing on key cell populations and functional enrichment to explore the pathogenesis of CKD. Oil red O staining and enzyme-linked immunosorbent assay (ELISA) were used to detect lipid droplets and free fatty acid (FFA). Quantitative real-time polymerase chain reaction (RT-PCR), western blot (WB) were used to verify the differential gene hydroxyacid oxidase 2 (HAO2) and fatty acid metabolic process in tissue to ensure the reliability of single-cell sequencing results. We successfully established a single-cell transcriptome atlas of blood and kidney tissue in rats with CKD, which were annotated into 14 cell subsets (MPCs, PT, Tc, DCT, B-IC, A-IC, CNT, ALOH, BC, Neu, Endo, Pla, NKT, Baso) according to marker gene, and the integrated single-cell atlas of rats showed a significant increase and decrease of MPCs and PTs in the CKD group, respectively. Functional analysis found extensive enrichment of metabolic-related pathways in PT cells, includes fatty acid metabolic process, cellular amino acid metabolic process and generation of precursor metabolites and energy. Immunohistochemical experiments determined that the differential gene HAO2 was localized in the renal tubules, and its expression was significantly reduced in CKD group compared with control, and oil red O staining showed that lipid droplets increased in the CKD group, after overexpression of HAO2 the lipid droplets was inhibited. ELISA assay showed that ATP content decreased in the CKD group and FFA increased in the CKD group. Moreover, the mitochondrial membrane potential of the cells in the OE-HAO2 group was significantly increased compared with OE-NC. The acyl-CoA oxidase 1(ACOX1), peroxisome proliferator-activated receptor alpha (PPARα), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) were decreased in the CKD group, while genes and proteins were increased after overexpression of HAO2, and the AMP-activated protein kinase (AMPK) phosphorylated proteins were increased, the acetyl-CoA carboxylase (ACC) phosphorylated proteins were decreased, reversely. Therefore, HAO2 may be an important regulator of fatty acid metabolic processes in CKD, and overexpression of HAO2 can enhance fatty acid metabolism by promoting fatty acid oxidation (FAO) pathway.

Neonatal Amino Acids and Acylcarnitines Associated With Maternal Blood Glucose Levels Throughout Pregnancy: Insights From the Beijing Birth Cohort Study.

To determine the association between maternal blood glucose patterns throughout pregnancy and neonatal amino acids and acylcarnitines. We conducted a prospective cohort study involving 11,457 singleton pregnant women without preexisting diabetes from the Beijing Birth Cohort Study, along with their neonates born between July 2021 and October 2022 in Beijing, China. Distinct maternal glucose trajectories were identified using a latent class model based on blood glucose levels across the three trimesters, and their association with neonatal circulating metabolites, including 11 amino acids and 33 acylcarnitines, was examined, adjusting for potential confounding factors. Three distinct groups of maternal glucose trajectories were identified: consistent normoglycemia (n = 8,648), mid-to-late gestational hyperglycemia (n = 2,540), and early-onset hyperglycemia (n = 269). Mid-to-late gestational hyperglycemia was associated with decreased levels of amino acids (alanine, arginine, ornithine, and proline) involved in the arginine and proline metabolism and urea cycle pathway, as well as increased levels of C4DC+C5-OH and decreased level of C6DC and C10:1. Early-onset hyperglycemia was associated with elevated levels of free acylcarnitine and C4DC+C5-OH and a decreased level of C10:1, involved in the fatty acid oxidation pathway. However, these associations were primarily observed in male neonates rather than in female neonates. Our findings revealed a significant link between maternal glucose trajectories throughout pregnancy and neonatal arginine and proline metabolism, urea cycle pathway, and fatty acid oxidation pathway. These results highlight the importance of maintaining optimal blood glucose levels throughout pregnancy to promote healthy neonatal metabolic outcomes.

Sex differences in metabolic adaptation in infants with cyanotic congenital heart disease.

Female infants with congenital heart disease (CHD) face significantly higher postoperative mortality rates after adjusting for cardiac complexity. Sex differences in metabolic adaptation to cardiac stressors may be an early contributor to cardiac dysfunction. In adult diseases, hypoxic/ischemic cardiomyocytes undergo a cardioprotective metabolic shift from oxidative phosphorylation to glycolysis which appears to be regulated in a sexually dimorphic manner. We hypothesize sex differences in cardiac metabolism are present in cyanotic CHD and detectable as early as the infant period. RNA sequencing was performed on blood samples (cyanotic CHD cases, n = 11; controls, n = 11) and analyzed using gene set enrichment analysis (GSEA). Global plasma metabolite profiling (UPLC-MS/MS) was performed using a larger representative cohort (cyanotic CHD, n = 27; non-cyanotic CHD, n = 11; unaffected controls, n = 12). Hallmark gene sets in glycolysis, fatty acid metabolism, and oxidative phosphorylation were significantly enriched in cyanotic CHD females compared to male counterparts, which was consistent with metabolomic differences between sexes. Minimal sex differences in metabolic pathways were observed in normoxic patients (both controls and non-cyanotic CHD cases). These observations suggest underlying differences in metabolic adaptation to chronic hypoxia between males and females with cyanotic CHD. Children with cyanotic CHD exhibit sex differences in utilization of glycolysis vs. fatty acid oxidation pathways to meet the high-energy demands of the heart in the neonatal period. Transcriptomic and metabolomic results suggest that under hypoxic conditions, males and females undergo metabolic shifts that are sexually dimorphic. These sex differences were not observed in neonates in normoxic conditions (i.e., non-cyanotic CHD and unaffected controls). The involved metabolic pathways are similar to those observed in advanced heart failure, suggesting metabolic adaptations beginning in the neonatal period may contribute to sex differences in infant survival.

Adipocytes and metabolism: Contributions to multiple myeloma

Obesity contributes to many cancers, including breast cancer and multiple myeloma, two cancers that often colonize the bone marrow (BM). Obesity often causes metabolic disease, but at the cellular level, there is uncertainty regarding how these shifts affect cellular phenotypes. Evidence is building that different types of fuel affect tumor cell metabolism, mitochondrial function, and signaling pathways differently, but tumor cells are also flexible and adapt to less-than ideal metabolic conditions, suggesting that single-pronged attacks on tumor metabolism may not be efficacious enough to be effective clinically. In this review, we describe the newest research at the pre-clinical level on how tumor metabolic pathways and energy sources affect cancer cells, with a special focus on multiple myeloma (MM). We also describe the known forward-feedback loops between bone marrow adipocytes (BMAds) and local tumor cells that support tumor growth. We describe how metabolic targets and transcription factors related to fatty acid (FA) oxidation, FA biosynthesis, glycolysis, oxidative phosphorylation (OXPHOS), and other pathways hold great promise as new vulnerabilities in myeloma cells. Specifically, we describe the importance of the acetyl-CoA synthetase (ACSS) and the acyl-CoA synthetase long chain (ACSL) families, which are both involved in FA metabolism. We also describe new data on the importance of lactate metabolism and lactate transporters in supporting the growth of tumor cells in a hypoxic BM microenvironment. We highlight new data showing the dependency of myeloma cells on the mitochondrial pyruvate carrier (MPC), which transports pyruvate to the mitochondria to fuel the tricarboxylic acid (TCA) cycle and electron transport chain (ETC), boosting OXPHOS. Inhibiting the MPC affects myeloma cell mitochondrial metabolism and growth, and synergizes with proteosome inhibitors in killing myeloma cells. We also describe how metabolic signaling pathways intersect established survival and proliferation pathways; for example, the fatty acid binding proteins (FABPs) affect MYC signaling and support growth, survival, and metabolism of myeloma cells. Our goal is to review the current the field so that novel, metabolic-focused therapeutic interventions and treatments can be imagined, developed and tested to decrease the burden of MM and related cancers.

Impacts of Non- and Whole-fat Milk Supplementation on Metabolism-Associated Fatty Liver Disease (MAFLD) in C57BL/6 Mice

Background: Metabolism-associated fatty liver disease (MAFLD) is a widespread metabolic disease affecting 25% of the global adult population following Westernized lifestyles. Lifestyle modifications, specifically adherence to healthy dietary patterns, are pivotal in preventing and mitigating this disease. Consuming milk and dairy products is considered a cornerstone of a healthy dietary pattern, gathering significant attention due to compelling evidence from observational studies. These studies suggest that a higher intake of milk and certain dairy products is associated with a reduced risk of MAFLD. However, the relative health benefits of high- compared to lower-fat milk is a current topic of interest, with ongoing debates about their equivalency in promoting metabolic health. Aims & Hypothesis: In a MAFLD mouse model, we aim to determine the dependence of milk’s fat content on hepatic steatosis and lipid metabolic pathways by comparing whole- (WFM) to non-fat (NFM) milk supplementation in high-fat diet-fed mice (HFD). We hypothesize that both WFM and NFM will significantly improve HFD-induced hepatic lipid accumulation but via differential molecular mechanisms. Methods: Two cohorts of n=24 and n=36 6-week-old male C57BL/6 mice were acclimatized for one week, then randomly assigned to a HFD (45 kcal% fat) or a low-fat diet (LFD; 10 kcal% fat) control group. The HFD mice were randomized to either a WFM or NFM treatment of 0.425 mL milk for 8 weeks. At the end of the study, mice underwent an insulin tolerance and pyruvate tolerance test and body composition was measured. The animals were then euthanized, tissues were collected, and hepatic lipid metabolism was compared using western blot, histology, hepatic lipid assays, gas chromatography, and qPCR. Statistics were then completed using GraphPad Prism software 7.0, utilizing T-test, one-way ANOVA, and Tukey’s post-hoc tests with a p-value ≤ 0.05 considered as statistically significant. Results: Body weight gain was significantly reduced in NFM groups compared to HFD and WFM, accounted for by a significant reduction in fat mass. ITT was unaltered when corrected to baseline, but NFM groups had significantly higher PTT values when corrected to baseline. Overnight-fasted blood glucose was significantly reduced in NFM animals compared to WFM animals, suggesting an altered metabolic state between the two treatment groups. Histological results indicate a significant reduction in lipid accumulation by the NFM group compared to the HFD group (p<0.05), with WFM trending towards a similar reduction (p=0.051). Hepatic triglyceride concentrations were significantly reduced in NFM animals compared to WFM and HFD animals, suggesting a greater effect of NFM in reducing hepatic steatosis. Hepatic molecular results display an enhancement of enzymes involved in fatty acid oxidation and export pathways in the NFM group. In contrast, WFM displays an enhancement of de novo lipogenesis, fatty acid uptake, and fatty acid oxidation. Conclusion: The findings suggest that NFM may be more effective at reducing hepatic steatosis through enhanced fatty acid oxidation and export. WFM may reduce steatosis less effectively because of counteractive effects on fatty acid uptake and de novo lipogenesis versus beta-oxidation. These results provide mechanistic evidence of the protective effects of milk on MAFLD. The funding sources for this project include the Alberta Diabetes Institute Studentship Grant, CIHR Canadian Graduate Studentship, and Dairy Farmers of Canada. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Transcriptome analysis reveals the mechanism of antifungal peptide epinecidin-1 against Botrytis cinerea by mitochondrial dysfunction and oxidative stress

The marine antifungal peptide epinecidin-1 (EPI) have been shown to inhibit Botrytis cinerea growth, while the molecular mechanism have not been explored based on omics technology. This study aimed to investigate the molecular mechanism of EPI against B. cinerea by transcriptome technology. Our findings indicated that a total of 1671 differentially expressed genes (DEGs) were detected in the mycelium of B. cinerea treated with 12.5 μmol/L EPI for 3 h, including 773 up-regulated genes and 898 down-regulated genes. Cluster analysis showed that DEGs (including steroid biosynthesis, (unsaturated) fatty acid biosynthesis) related to cell membrane metabolism were significantly down-regulated, and almost all DEGs involved in DNA replication were significantly inhibited. In addition, it also induced the activation of stress-related pathways, such as the antioxidant system, ATP-binding cassette transporter (ABC) and MAPK signaling pathways, and interfered with the tricarboxylic acid (TCA) cycle and oxidative phosphorylation pathways related to mitochondrial function. The decrease of mitochondrial related enzyme activities (succinate dehydrogenase, malate dehydrogenase and adenosine triphosphatase), the decrease of mitochondrial membrane potential and the increase content of hydrogen peroxide further confirmed that EPI treatment may lead to mitochondrial dysfunction and oxidative stress. Based on this, we speculated that EPI may impede the growth of B. cinerea through its influence on gene expression, and may lead to mitochondrial dysfunction and oxidative stress.

The oncogenic role and regulatory mechanism of ACAA2 in human ovarian cancer.

Acetyl-CoAacyltransferase2 (ACAA2) is a key enzyme in the fatty acid oxidation pathway that catalyzes the final step of mitochondrial β oxidation, which plays an important role in fatty acid metabolism. The expression of ACAA2 is closely related to the occurrence and malignant progression of tumors. However, the function of ACAA2 in ovarian cancer is unclear. The expression level and prognostic value of ACAA2 were analyzed by databases. Gain and loss of function were carried out to explore the function of ACAA2 in ovarian cancer. RNA-seq and bioinformatics methods were applied to illustrate the regulatory mechanism of ACAA2. ACAA2 overexpression promoted the growth, proliferation, migration, and invasion of ovarian cancer, and ACAA2 knockdown inhibited the malignant progression of ovarian cancer as well as the ability of subcutaneous tumor formation in nude mice. At the same time, we found that OGT can induce glycosylation modification of ACAA2 and regulate the karyoplasmic distribution of ACAA2. OGT plays a vital role in ovarian cancer as a function of oncogenes. In addition, through RNA-seq sequencing, we found that ACAA2 regulates the expression of DIXDC1. ACAA2 regulated the malignant progression of ovarian cancer through the WNT/β-Catenin signaling pathway probably. ACAA2 is an oncogene in ovarian cancer and has the potential to be a target for ovarian cancer therapy.

Transcription Factor McHB7 Improves Ice Plant Drought Tolerance through ABA Signaling Pathway.

As global climate change continues, drought episodes have become increasingly frequent. Studying plant stress tolerance is urgently needed to ensure food security. The common ice plant is one of the model halophyte plants for plant stress biology research. This study aimed to investigate the functions of a newly discovered transcription factor, Homeobox 7 (HB7), from the ice plant in response to drought stress. An efficient Agrobacterium-mediated transformation method was established in the ice plant, where ectopic McHB7 expression may be sustained for four weeks. The McHB7 overexpression (OE) plants displayed drought tolerance, and the activities of redox enzymes and chlorophyll content in the OE plants were higher than the wild type. Quantitative proteomics revealed 1910 and 495 proteins significantly changed in the OE leaves compared to the wild type under the control and drought conditions, respectively. Most increased proteins were involved in the tricarboxylic acid cycle, photosynthesis, glycolysis, pyruvate metabolism, and oxidative phosphorylation pathways. Some were found to participate in abscisic acid signaling or response. Furthermore, the abscisic acid levels increased in the OE compared with the wild type. McHB7 was revealed to bind to the promoter motifs of Early Responsive to Dehydration genes and abscisic acid-responsive genes, and protein-protein interaction analysis revealed candidate proteins responsive to stresses and hormones (e.g., abscisic acid). To conclude, McHB7 may contribute to enhance plant drought tolerance through abscisic acid signaling.

Impacts of superfine grinding on structural characteristics and lipid‐lowering effect of bitter melon polysaccharides

SummaryIn this study, the effects of superfine grinding on the structural and physicochemical properties of bitter melon polysaccharides (BPS) were investigated, and Caenorhabditis elegans model was used to evaluate fat‐lowering bioactivities of BPS. Results illustrated that superfine grinding resulted in high extraction of BPSs yielding with altered microstructure, different monosaccharide compositions and molecular weights. In addition, improved water/oil‐holding capacity, solubility and swelling capacity of polysaccharides were observed following superfine grinding. Furthermore, C. elegans study revealed that BPSs exhibited strong inhibitory effects on lipid accumulation, especially BPS‐25 (extracted from bitter melon treated with superfine grinding) reducing the triglyceride content from 9.49 to 1.85 mg g−1.prot. Mechanistic study showed that the lipid‐lowering effects of BPSs largely dependent on the insulin signalling pathway, fatty acid oxidation or lipolysis pathways. In all, our study underscore that superfine grinding can effectively improve the lipid‐lowing effects of bitter melon polysaccharides.

Abstract 4157: Combining hyperpolarized magnetic resonance and positron emission tomography to interrogate prostate cancer metabolism

Abstract Background: There is an unmet clinical need for imaging biomarkers to distinguish indolent from aggressive prostate cancer (PCa). Many advanced and aggressive PCa patients receiving anti-androgens (enzalutamide) develop resistance. It is hypothesized that dysregulated cell metabolism is a key driver for PCa progression and therapy resistance. Two pathways commonly involved in PCa are glycolysis and fatty acid metabolism. Therefore, metabolic imaging and metabolomics were performed on enzalutamide sensitive/resistant, Androgen Receptor dependent (AR+) and AR independent (AR-) patient derived xenograft (PDX) tumors. To interrogate both pathways, [1-13C]-pyruvate hyperpolarized magnetic resonance spectroscopy (HP-MRS) and [18F]-fluorodeoxyglucose positron emission tomography (18F-FDG) for glycolysis, and [18F]-fluoro-pivalic acid positron emission tomography (18F-FPIA) for fatty acid metabolism were employed. 1H Nuclear Magnetic Resonance (NMR) spectroscopy and liquid chromatography with tandem mass spectrometry (LC-MS-MS) were employed for validation purposes. Methods: [1-13C]-labeled pyruvic acid was hyperpolarized using a DNP HyperSense polarizer following standard protocol. Anatomical MRI and 13C-MRS were obtained on different PCa PDX mouse models at two different time points using a Bruker 7T scanner. The PDX models included AR+ enzalutamide sensitive (183-A, 180-30), AR+ enzalutamide resistant (274-4), and AR- (144-4, 114-B). The time points imaged were before and after 7 days of treatment with enzalutamide. 1H-NMR spectroscopy was performed on extracted tissue. Simultaneously, 18F-FPIA-PET imaging were acquired on the same models on an Albira trimodal PET station. Results: The dynamic metabolic flux ratio, lactate-to-pyruvate (Lac/Pyr) was determined in vivo and used as a treatment response marker. The Lac/Pyr ratios were significantly higher in resistant tumors compared to sensitive tumors (p<0.01). The enzalutamide sensitive group had a lower Lac/Pyr ratio after treatment, while the enzalutamide resistant group had a higher Lac/Pyr ratio. After treatment, there was also a decrease in [18F]-FDG uptake, corresponding to the HP-MRS data. This was expected as both Pyruvate and [18F]-FDG interrogate the glycolytic pathway. As for the fatty acid metabolic imaging, PET imaging also revealed that [18F]-FPIA is transported into the tumors, and we are currently exploring how its uptake varies between AR (+/-) PCa-PDX tumors and enzalutamide resistant/sensitive models. Ex vivo NMR and mass spectrometry-based metabolomics validated the in vivo HP-MRS data with higher lactate levels in drug resistant tumors. Conclusion: Combining HP-MRS and PET presents an exciting opportunity to realize imaging-based personalized medicine in different AR (+/-) PCa-PDX preclinical models by interrogating glycolysis and fatty acid oxidation pathways. Citation Format: Muxin Wang, José S. Enriquez, Prasanta Dutta, Jenny Han, Peter Shepherd, Daniel Frigo, Federica Pisaneschi, Pratip K. Bhattacharya. Combining hyperpolarized magnetic resonance and positron emission tomography to interrogate prostate cancer metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4157.

Hypoxia expedites the progression of papillary thyroid carcinoma by promoting the CPT1A-mediated fatty acid oxidative pathway.

Hypoxia has been reported to promote the proliferation and migration of thyroid cancer, while the special mechanism was still unclear. HIF-1α/carnitine palmitoyl-transferase 1A (CPT1A) was found to be associated with papillary thyroid carcinoma (PTC) but the biological role of CPT1A in PTC was not explored. The effects of hypoxia and carnitine palmitoyl-transferase 1A (CPT1A) expression on PTC cells were determined by cell counting kit-8 assay, detection of oxidative stress, inflammation response and mitochondrial membrane motential (MMP). Oil Red O staining and the detection of free fatty acids were performed to assess the status of lipid metabolism. Flow cytometric analysis was performed to assess cell apoptosis. Quantitative polymerase chain reaction (qPCR) and western blot analysis were applied to investigate the expressions of CPT1A and HIF-1α and the molecules involved cell function. The expressions of CPT1A and HIF-1α were significantly increased in PTC cells with or without hypoxia treatment. CPT1A overexpression or silencing promoted or inhibited cell viability, and hypoxia further repressed cell viability. In addition, CPT1A overexpression alleviates hypoxia-induced increased oxidative stress, inflammation response and elevated MMP. CPT1A overexpression enhanced palmitic acid-induced decreased cell growth, enhanced the metabolic capacity of free fatty acid and suppressed cell apoptosis. Animal experiments showed that CPT1A overexpression promoted PTC tumor growth, reduced lipid deposition, oxidative stress and inflammation, as well as enhancing cell function indicators. However, CPT1A silencing showed the opposite effects both in vitro and in vivo. Hypoxia induces the high expression of HIF-1α/CPT1A, thereby reprogramming the lipid metabolism of PTC cells for adapting the hypoxia environment, meanwhile inhibiting the cell damage and apoptosis caused by oxidative stress.

Immunometabolic features of natural killer cells are associated with infection outcomes in critical illness.

Immunosuppression increases the risk of nosocomial infection in patients with chronic critical illness. This exploratory study aimed to determine the immunometabolic signature associated with nosocomial infection during chronic critical illness. We prospectively recruited patients who were admitted to the respiratory care center and who had received mechanical ventilator support for more than 10 days in the intensive care unit. The study subjects were followed for the occurrence of nosocomial infection until 6 weeks after admission, hospital discharge, or death. The cytokine levels in the plasma samples were measured. Single-cell immunometabolic regulome profiling by mass cytometry, which analyzed 16 metabolic regulators in 21 immune subsets, was performed to identify immunometabolic features associated with the risk of nosocomial infection. During the study period, 37 patients were enrolled, and 16 patients (43.2%) developed nosocomial infection. Unsupervised immunologic clustering using multidimensional scaling and logistic regression analyses revealed that expression of nuclear respiratory factor 1 (NRF1) and carnitine palmitoyltransferase 1a (CPT1a), key regulators of mitochondrial biogenesis and fatty acid transport, respectively, in natural killer (NK) cells was significantly associated with nosocomial infection. Downregulated NRF1 and upregulated CPT1a were found in all subsets of NK cells from patients who developed a nosocomial infection. The risk of nosocomial infection is significantly correlated with the predictive score developed by selecting NK cell-specific features using an elastic net algorithm. Findings were further examined in an independent cohort of COVID-19-infected patients, and the results confirm that COVID-19-related mortality is significantly associated with mitochondria biogenesis and fatty acid oxidation pathways in NK cells. In conclusion, this study uncovers that NK cell-specific immunometabolic features are significantly associated with the occurrence and fatal outcomes of infection in critically ill population, and provides mechanistic insights into NK cell-specific immunity against microbial invasion in critical illness.

ACAD10 is not required for metformin's metabolic actions or for maintenance of whole-body metabolism in C57BL/6J mice.

Acyl-coenzyme A dehydrogenase family member 10 (ACAD10) is a mitochondrial protein purported to be involved in the fatty acid oxidation pathway. Metformin is the most prescribed therapy for type 2 diabetes; however, its precise mechanisms of action(s) are still being uncovered. Upregulation of ACAD10 is a requirement for metformin's ability to inhibit growth in cancer cells and extend lifespan in Caenorhabditis elegans. However, it is unknown whether ACAD10 plays a role in metformin's metabolic actions. We assessed the role for ACAD10 on whole-body metabolism and metformin action by generating ACAD10KO mice on a C57BL/6J background via CRISPR-Cas9 technology. In-depth metabolic phenotyping was conducted in both sexes on a normal chow and high fat-high sucrose diet. Compared with wildtype mice, we detected no difference in body composition, energy expenditure or glucose tolerance in male or female ACAD10KO mice, on a chow diet or high-fat, high-sucrose diet (p ≥ .05). Hepatic mitochondrial function and insulin signalling was not different between genotypes under basal or insulin-stimulated conditions (p ≥ .05). Glucose excursions following acute administration of metformin before a glucose tolerance test were not different between genotypes nor was body composition or energy expenditure altered after 4 weeks of daily metformin treatment (p ≥ .05). Despite the lack of a metabolic phenotype, liver lipidomic analysis suggests ACAD10 depletion influences the abundance of specific ceramide species containing very long chain fatty acids, while metformin treatment altered clusters of cholesterol ester, plasmalogen, phosphatidylcholine and ceramide species. Loss of ACAD10 does not alter whole-body metabolism or impact the acute or chronic metabolic actions of metformin in this model.