Carnitine Palmitoyltransferase Research Articles

Investigation on the lipid-lowering effect and mechanism by combining turmeric with hawthorn in C57BL/6 obese mice.

Study on the hypolipidemic effect of turmeric combined with hawthorn on C57BL/6 obese mice and its possible mechanism. C57 mice were fed with 60% high-fat diet for 8 weeks to establish an obesity model, and 4 mice were slaughtered to verify whether the modeling was successful. The successful mice were divided into model group (HFD), positive group (high fat feed group [HFD]+simvastatin group [SIM]), turmeric group (HFD+TUR), hawthorn group (HFD+HAW), and para-medicine group (HFD+para-drug group [DOU]) for 4 weeks by gavage intervention. Different intervention groups had certain lipid-lowering effects, and the para-medicine group showed significant differences (p<0.05, p<0.01, p<0.001) in reducing serum total cholesterol, triglycerides, low-density lipoprotein cholesterol, glutamic acid transaminase (ALT), glutamic acid transaminase (AST), and increasing high-density lipoprotein cholesterol. In the para-medicine group, the protein expression of peroxisome proliferator-activated receptor γ, fatty acid synthase, platelet-reactive protein receptor 36, and CCAAT/enhancer binding protein α were significantly downregulated, and the protein expression of carnitine palmitoyl transferase1 and peroxisome proliferator-activated receptor α protein expression (p<0.01, p<0.001), thus suggesting that turmeric and hawthorn are superior to turmeric and hawthorn alone in enhancing lipid metabolism-related mechanisms. Combined effects of turmeric and hawthorn improve lipid metabolism in mice, protect the liver, and improve the protein expression of liver-related genes. This study can lay the theoretical basis for the future association of medicinal food products and the development of related weight loss products.

Effect of high plant protein diet supplemented with Lysophospholipids-butyrate on the growth performance, liver health and intestinal morphology of Largemouth bass (Micropterus salmoides)

This study was conducted to evaluate the effects of dietary supplementation with lysophospholipids-butyrate (LPB) in a high plant protein diet on the growth performance, liver health, and intestinal morphology of Largemouth bass (Micropterus salmoides). Three experimental diets were formulated: a positive control diet (PC) containing 15.00 % soybean meal (SBM) and 13 % chicken meal；a high-plant-protein diet (HPP) with 28.00 % SBM; a diet (LPB) supplemented LPB at 0.1 % in HPP. Largemouth bass with an average initial body weight of 9.3 g were fed for 60 days, with 4 replicates per group and 20 fish per replicate. The results demonstrated that the HPP group exhibited significantly lower final body weight (FBW), weight gain rate (WGR) and specific growth rate (SGR) compared to the PC group. Moreover, the HPP diet induced a notable increase in liver collagen fiber and liver lipid content, which was alleviated by LPB supplementation. In comparison to the HPP group, the LPB group showed significant increases in serum albumin and albumin/globulin, along with a significant decrease in alanine aminotransferase activity (P < 0.05). Compared with the PC group, the mRNA levels of acetyl-CoA carboxylase-1 (ACC-1), diacylglycerol acyltransferase (DGAT), carnitine palmitoyl transferase-1 (CPT-1) and tumor necrosis factor-α (TNF-α) in HPP group were increased significantly (P < 0.05), while adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL) as well as apoptotic gene B-cell lymphoma-2 (Bcl-2) were significantly down-regulated. The mRNA levels of fatty acid synthase (FAS), ACC-1, peroxisome proliferator activated receptor-α (PPAR-α), ATGL, interleukin-1β (IL-1β), transforming growth factor-β (TGF-β) and Bcl-2 were up-regulated (P < 0.05), while DGAT and TNF-α were down-regulated in the LPB supplemented groups than that in the HPP group (P < 0.05). In conclusion, the supplementation of 0.1 % LPB can alleviate liver lipid accumulation and fibrosis caused by high level of soybean meal.

APC/C-regulated CPT1C promotes tumor progression by upregulating the energy supply and accelerating the G1/S transition

BackgroundIn addition to functioning as a precise monitoring mechanism in cell cycle, the anaphase-promoting complex/cyclosome (APC/C) is reported to be involved in regulating multiple metabolic processes by facilitating the ubiquitin-mediated degradation of key enzymes. Fatty acid oxidation is a metabolic pathway utilized by tumor cells that is crucial for malignant progression; however, its association with APC/C remains to be explored.MethodsCell cycle synchronization, immunoblotting, and propidium iodide staining were performed to investigate the carnitine palmitoyltransferase 1 C (CPT1C) expression manner. Proximity ligation assay and co-immunoprecipitation were performed to detect interactions between CPT1C and APC/C. Flow cytometry, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium, inner salt (MTS) assays, cell-scratch assays, and transwell assays and xenograft transplantation assays were performed to investigate the role of CPT1C in tumor progression in vitro and in vivo. Immunohistochemistry was performed on tumor tissue microarray to evaluate the expression levels of CPT1C and explore its potential clinical value.ResultsWe identified CPT1C as a novel APC/C substrate. CPT1C protein levels exhibited cell cycle-dependent fluctuations, peaking at the G1/S boundary. Elevated CPT1C accelerated the G1/S transition, facilitating tumor cell proliferation in vitro and in vivo. Furthermore, CPT1C enhanced fatty acid utilization, upregulated ATP levels, and decreased reactive oxygen species levels, thereby favoring cell survival in a harsh metabolic environment. Clinically, high CPT1C expression correlated with poor survival in patients with esophageal squamous cell carcinoma.ConclusionsOverall, our results revealed a novel interplay between fatty acid utilization and cell cycle machinery in tumor cells. Additionally, CPT1C promoted tumor cell proliferation and survival by augmenting cellular ATP levels and preserving redox homeostasis, particularly under metabolic stress. Therefore, CPT1C could be an independent prognostic indicator in esophageal squamous cell carcinoma.

Glycolytic enzyme PFKL governs lipolysis by promoting lipid droplet-mitochondria tethering to enhance β-oxidation and tumor cell proliferation.

Lipid droplet tethering with mitochondria for fatty acid oxidation is critical for tumor cells to counteract energy stress. However, the underlying mechanism remains unclear. Here, we demonstrate that glucose deprivation induces phosphorylation of the glycolytic enzyme phosphofructokinase, liver type (PFKL), reducing its activity and favoring its interaction with perilipin 2 (PLIN2). On lipid droplets, PFKL acts as a protein kinase and phosphorylates PLIN2 to promote the binding of PLIN2 to carnitine palmitoyltransferase 1A (CPT1A). This results in the tethering of lipid droplets and mitochondria and the recruitment of adipose triglyceride lipase to the lipid droplet-mitochondria tethering regions to engage lipid mobilization. Interfering with this cascade inhibits tumor cell proliferation, promotes apoptosis and blunts liver tumor growth in male mice. These results reveal that energy stress confers a moonlight function to PFKL as a protein kinase to tether lipid droplets with mitochondria and highlight the crucial role of PFKL in the integrated regulation of glycolysis, lipid metabolism and mitochondrial oxidation.

Metabolic Reprogramming: A Byproduct or a Driver of Cardiomyocyte Proliferation?

Defining mechanisms of cardiomyocyte proliferation should guide the understanding of endogenous cardiac regeneration and could lead to novel treatments for diseases such as myocardial infarction. In the neonatal heart, energy metabolic reprogramming (phenotypic alteration of glucose, fatty acid, and amino acid metabolism) parallels cell cycle arrest of cardiomyocytes. The metabolic reprogramming occurring shortly after birth is associated with alterations in blood oxygen levels, metabolic substrate availability, hemodynamic stress, and hormone release. In the adult heart, myocardial infarction causes metabolic reprogramming but these changes cannot stimulate sufficient cardiomyocyte proliferation to replace those lost by the ischemic injury. Some putative pro-proliferative interventions can induce the metabolic reprogramming. Recent data show that altering the metabolic enzymes PKM2 [pyruvate kinase 2], LDHA [lactate dehydrogenase A], PDK4 [pyruvate dehydrogenase kinase 4], SDH [succinate dehydrogenase], CPT1b [carnitine palmitoyl transferase 1b], or HMGCS2 [3-hydroxy-3-methylglutaryl-CoA synthase 2] is sufficient to partially reverse metabolic reprogramming and promotes adult cardiomyocyte proliferation. How metabolic reprogramming regulates cardiomyocyte proliferation is not clearly defined. The possible mechanisms involve biosynthetic pathways from the glycolysis shunts and the epigenetic regulation induced by metabolic intermediates. Metabolic manipulation could represent a new approach to stimulate cardiac regeneration; however, the efficacy of these manipulations requires optimization, and novel molecular targets need to be defined. In this review, we summarize the features, triggers, and molecular regulatory networks responsible for metabolic reprogramming and discuss the current understanding of metabolic reprogramming as a critical determinant of cardiomyocyte proliferation.

Metabolic predictors of COVID-19 mortality and severity: a survival analysis.

The global healthcare burden of COVID-19 pandemic has been unprecedented with a high mortality. Metabolomics, a powerful technique, has been increasingly utilized to study the host response to infections and to understand the progression of multi-system disorders such as COVID-19. Analysis of the host metabolites in response to SARS-CoV-2 infection can provide a snapshot of the endogenous metabolic landscape of the host and its role in shaping the interaction with SARS-CoV-2. Disease severity and consequently the clinical outcomes may be associated with a metabolic imbalance related to amino acids, lipids, and energy-generating pathways. Hence, the host metabolome can help predict potential clinical risks and outcomes. In this prospective study, using a targeted metabolomics approach, we studied the metabolic signature in 154 COVID-19 patients (males=138, age range 48-69 yrs) and related it to disease severity and mortality. Blood plasma concentrations of metabolites were quantified through LC-MS using MxP Quant 500 kit, which has a coverage of 630 metabolites from 26 biochemical classes including distinct classes of lipids and small organic molecules. We then employed Kaplan-Meier survival analysis to investigate the correlation between various metabolic markers, disease severity and patient outcomes. A comparison of survival outcomes between individuals with high levels of various metabolites (amino acids, tryptophan, kynurenine, serotonin, creatine, SDMA, ADMA, 1-MH and carnitine palmitoyltransferase 1 and 2 enzymes) and those with low levels revealed statistically significant differences in survival outcomes. We further used four key metabolic markers (tryptophan, kynurenine, asymmetric dimethylarginine, and 1-Methylhistidine) to develop a COVID-19 mortality risk model through the application of multiple machine-learning methods. Metabolomics analysis revealed distinct metabolic signatures among different severity groups, reflecting discernible alterations in amino acid levels and perturbations in tryptophan metabolism. Notably, critical patients exhibited higher levels of short chain acylcarnitines, concomitant with higher concentrations of SDMA, ADMA, and 1-MH in severe cases and non-survivors. Conversely, levels of 3-methylhistidine were lower in this context.

AMPK deficiency inhibits fatty acid oxidation in endothelial progenitor cells to aggravate impaired angiogenesis after ischemic stroke in hyperlipidemic mice

ABSTRACT Background Hyperlipidemia is a risk factor for stroke, and worsens neurological outcome after stroke. Endothelial progenitor cells (EPCs), which become dysfunctional in cerebral ischemia, hold capacity to promote revascularization. Objective We investigated the role of dyslipidemia in impairment of EPC-mediated angiogenesis in cerebral ischemic mice. Methods and Results The high fat diet (HFD)-fed mice following by ischemic stroke exhibited increased infarct volumes and neurological severity scores, and poorer angiogenesis. Bone marrow-EPCs treated with palmitic acid (PA) showed impaired functions and inhibited activity of AMP-activated protein kinase (AMPK). Notably, AMPK deficiency aggravated EPC dysfunction, further decreased mitochondrial membrane potential, and increased reactive oxygen species level in EPCs with PA treatment. Furthermore, the expression of fatty acid oxidation (FAO)-related genes was remarkably reduced, and carnitine palmitoyltransferase 1A (CPT1A) protein expression was downregulated in AMPK-deficient EPCs. AMPK deficiency aggravated neurological severity scores and angiogenesis in ischemic brain of HFD-fed mice, accompanied by suppressed protein level of CPT1A. EPC transplantation corrected impaired neurological severity scores and angiogenesis in AMPK-deficient mice. Conclusion Our findings suggest that AMPK deficiency aggravates poor angiogenesis in ischemic brain by mediating FAO and oxidative stress thereby inducing EPC dysfunction in hyperlipidemic mice.

CPT1C-positive cancer-associated fibroblast facilitates immunosuppression through promoting IL-6-induced M2-like phenotype of macrophage

ABSTRACT Cancer-associated fibroblasts (CAFs) exhibit remarkable phenotypic heterogeneity, with specific subsets implicated in immunosuppression in various malignancies. However, whether and how they attenuate anti-tumor immunity in gastric cancer (GC) remains elusive. CPT1C, a unique isoform of carnitine palmitoyltransferase pivotal in regulating fatty acid oxidation, is briefly indicated as a protumoral metabolic mediator in the tumor microenvironment (TME) of GC. In the present study, we initially identified specific subsets of fibroblasts exclusively overexpressing CPT1C, hereby termed them as CPT1C+CAFs. Subsequent findings indicated that CPT1C+CAFs fostered a stroma-enriched and immunosuppressive TME as they correlated with extracellular matrix-related molecular features and enrichment of both immunosuppressive subsets, especially M2-like macrophages, and multiple immune-related pathways. Next, we identified that CPT1C+CAFs promoted the M2-like phenotype of macrophage in vitro. Bioinformatic analyses unveiled the robust IL-6 signaling between CPT1C+CAFs and M2-like phenotype of macrophage and identified CPT1C+CAFs as the primary source of IL-6. Meanwhile, suppressing CPT1C expression in CAFs significantly decreased IL-6 secretion in vitro. Lastly, we demonstrated the association of CPT1C+CAFs with therapeutic resistance. Notably, GC patients with high CPT1C+CAFs infiltration responded poorly to immunotherapy in clinical cohort. Collectively, our data not only present the novel identification of CPT1C+CAFs as immunosuppressive subsets in TME of GC, but also reveal the underlying mechanism that CPT1C+CAFs impair tumor immunity by secreting IL-6 to induce the immunosuppressive M2-like phenotype of macrophage in GC.

Effects of Mactra chinenesis Peptides on Alcohol-Induced Acute Liver Injury and Intestinal Flora in Mice.

Food-borne bioactive peptides have shown promise in preventing and mitigating alcohol-induced liver injury. This study was the first to assess the novel properties of Mactra chinenesis peptides (MCPs) in mitigating acute alcoholic liver injury in mice, and further elucidated the underlying mechanisms associated with this effect. The results showed that MCPs can improve lipid metabolism by modulating the AMPK signaling pathway, decreasing fatty acid synthase activity, and increasing carnitine palmitoyltransferase 1a activity. Meanwhile, MCPs ameliorate inflammation by inhibiting the NF-κB activation, leading to reduced levels of pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-1β). Additionally, a 16S rDNA sequencing analysis revealed that MCPs can restore the balance of gut microbiota and increase the relative abundance of beneficial bacteria. These findings suggest that supplementation of MCPs could attenuate alcohol intake-induced acute liver injury, and, thus, may be utilized as a functional dietary supplement for the successful treatment and prevention of acute liver injury.

Sirt5 improves cardiomyocytes fatty acid metabolism and ameliorates cardiac lipotoxicity in diabetic cardiomyopathy via CPT2 de-succinylation

RationaleThe disruption of the balance between fatty acid (FA) uptake and oxidation (FAO) leads to cardiac lipotoxicity, serving as the driving force behind diabetic cardiomyopathy (DbCM). Sirtuin 5 (Sirt5), a lysine de-succinylase, could impact diverse metabolic pathways, including FA metabolism. Nevertheless, the precise roles of Sirt5 in cardiac lipotoxicity and DbCM remain unknown. ObjectiveThis study aims to elucidate the role and underlying mechanism of Sirt5 in the context of cardiac lipotoxicity and DbCM. Methods and resultsThe expression of myocardial Sirt5 was found to be modestly elevated in diabetic heart failure patients and mice. Cardiac dysfunction, hypertrophy and lipotoxicity were exacerbated by ablation of Sirt5 but improved by forced expression of Sirt5 in diabetic mice. Notably, Sirt5 deficiency impaired FAO without affecting the capacity of FA uptake in the diabetic heart, leading to accumulation of FA intermediate metabolites, which mainly included medium- and long-chain fatty acyl-carnitines. Mechanistically, succinylomics analyses identified carnitine palmitoyltransferase 2 (CPT2), a crucial enzyme involved in the reconversion of fatty acyl-carnitines to fatty acyl-CoA and facilitating FAO, as the functional succinylated substrate mediator of Sirt5. Succinylation of Lys424 in CPT2 was significantly increased by Sirt5 deficiency, leading to the inactivation of its enzymatic activity and the subsequent accumulation of fatty acyl-carnitines. CPT2 K424R mutation, which mitigated succinylation modification, counteracted the reduction of enzymatic activity in CPT2 mediated by Sirt5 deficiency, thereby attenuating Sirt5 knockout-induced FAO impairment and lipid deposition. ConclusionsSirt5 deficiency impairs FAO, leading to cardiac lipotoxicity in the diabetic heart through the succinylation of Lys424 in CPT2. This underscores the potential roles of Sirt5 and CPT2 as therapeutic targets for addressing DbCM.

4,4-Diallyl curcumin bis(2,2-hydroxymethyl)propanoate ameliorates nonalcoholic steatohepatitis in methionine-choline-deficient diet and Western diet mouse models.

Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease (NAFLD) that causes severe liver damage, fibrosis, and scarring. Despite its potential to progress to cirrhosis or hepatic failure, approved drugs or treatments are currently unavailable. We developed 4,4-diallyl curcumin bis(2,2-hydroxymethyl)propanoate, also known as 35e, which induces upregulation of mitochondrial proteins including carnitine palmitoyltransferase I (CPT-I), carnitine palmitoyltransferase II, heat shock protein 60, and translocase of the outer mitochondrial membrane 20. Among these proteins, the upregulated expression of CPT-I was most prominent. CPT-I plays a crucial role in transporting carnitine across the mitochondrial inner membrane, thereby initiating mitochondrial β-oxidation of fatty acids. Given recent research showing that CPT-I activation could be a viable pathway for NASH treatment, we hypothesized that 35e could serve as a potential agent for treating NASH. The efficacy of 35e in treating NASH was evaluated in methionine- and choline-deficient (MCD) diet- and Western diet (WD)-induced models that mimic human NASH. In the MCD diet-induced model, both short-term (2 weeks) and long-term (7 weeks) treatment with 35e effectively regulated elevated serum alanine aminotransferase (ALT)/aspartate aminotransferase (AST) concentrations and histological inflammation. However, the antisteatotic effect of 35e was obtained only in the short-term treatment group. As a comparative compound in the MCD diet-induced model, curcumin treatment did not produce significant regulatory effects on the liver triglyceride/total cholesterol, serum ALT/AST, or hepatic steatosis. In the WD-induced model, 35e ameliorated hepatic steatosis and hepatic inflammation, while increasing serum AST and hepatic lipid content. A decrease in epididymal adipose tissue weight and serum free fatty acid concentration suggested that 35e may promote lipid metabolism or impede lipid accumulation. Overall, 35e displayed significant antilipid accumulation and antifibrotic effects in the two complementary mice models. The development of new curcumin derivatives with the ability to induce CPT-I upregulation could further underscore their efficacy as anti-NASH agents.

Pathophysiology of Carnitine Palmitoyltransferase 2 (CPT2) Deficiency in the Dahl Salt-sensitive R at

Carnitine palmitoyltransferase 2 (CPT2) is an essential enzyme of the carnitine shuttle, which facilitates fatty acid -oxidation in mitochondria. This study aims to characterize the various effects of CPT2 deficiency on the Dahl salt-sensitive (SS) rat metabolome and its concomitant influence on renal homeostasis. CRISPR/Cas9 was used to insert a single base pair into the SS Cpt2 gene, causing a frameshift mutation found to be lethal in homozygotes (SSCpt2−/−). Western blotting and qPCR analysis of renal cortex tissue confirmed a reduced expression of CPT2 in heterozygous (SSCpt2+/-) rats compared to wild-type (WT) littermates; therefore, male and female heterozygotes were used for all experiments. Lipid metabolomics of renal cortex samples collected from SSCpt2+/- animals at 8 weeks old on a baseline 0.4% NaCl diet revealed a significant upregulation in inflammatory lipids such as 11-HETE (p&lt;0.01) and 12-HHT (p&lt;0.05) when compared to WT littermates. Urine analysis from the SSCpt2+/- group demonstrated a severe reduction in acetoacetic acid production (p&lt;0.001), indicating ketogenesis is likely impacted by the loss of CPT2 in -oxidation. Additionally, TCA cycle metabolites fumaric acid (p&lt;0.05) and oxaloacetic acid (p&lt;0.01) are significantly downregulated in urine from SSCpt2+/- animals. Radio telemeters were implanted into the rats at 8 weeks of age to continuously record mean arterial pressure (MAP) and monitor the development of SS hypertension over the course of several dietary treatment protocols. Three weeks of either a 4% NaCl high-salt (HS) diet or a HS + ketogenic (HSK) diet with equivalent caloric content (4:1 caloric ratio, fat: carbohydrate) were administered to the animals. No difference in MAP elevation occurred between groups after the HS challenge alone, but SSCpt2+/- animals on the HSK diet had a significantly attenuated development of hypertension (p=0.03). Further metabolic analysis after the HSK diet illustrated that both groups had similar increases in long-chain fatty acids, liver enzymes, and cholesterol levels with a decrease in short-chain fatty acids. These experiments show that the partial loss of CPT2 in the Dahl SS rat leads to dysregulation across multiple metabolic pathways. Moreover, a ketogenic diet appears to protect heterozygous animals from the development of salt-sensitive hypertension. Funding: NIH R35 HL135749 and VA I01 BX004024. 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.

Emodin nanocapsules inhibit acute pancreatitis by regulating lipid metabolic reprogramming in macrophage polarization

BackgroundEmodin is a chemical compound found in traditional Chinese herbs. It possesses anti-inflammatory and many other pharmacological effects. Our previous study showed that emodin significantly alleviates the inflammation effect of severe acute pancreatitis (SAP). However, its poor solubility, high toxicity and limited pancreas retention time hinder its clinical application. PurposeWe aimed to prepare emodin nanocapsules with improved bioavailability to achieve the controlled release of emodin by targeting macrophages. Further, the mechanism of mannose-conjugated chitosan-coated lipid nanocapsules loaded with emodin (M-CS-E-LNC) in the treatment of SAP was explored. MethodsM-CS-E-LNC were prepared by the phase inversion method with slight modification. The expression of inflammation mediators and the anti-inflammation efficacy of M-CS-E-LNC were examined by ELISA, IHC and IF in macrophage cells and LPS-induced SAP mice. IVIS spectrum imaging and HPLC were applied to explore the controlled release of M-CS-E-LNC in the pancreas. LC-MS/MS was performed for lipidomics analysis of macrophages. Moreover, a vector-based short hairpin RNA (shRNA) method was used to silence CTP1 gene expression in macrophage cells. ResultsThe levels of inflammatory mediators in macrophages were markedly decreased after treatment with M-CS-E-LNC. The same anti-inflammation effects were detected in SAP mouse through the analysis of serum levels of amylase, TNF-α and IL-6. Importantly, M-CS-E-LNC allowed the emodin to selectively accumulate at pancreas and gastrointestinal tissues, thus exhibiting a targeted release. Mechanistically, the M-CS-E-LNC treatment group showed up-regulated expression of the carnitine palmitoyltransferase 1 (CPT1) protein which promoted intracellular long-chain fatty acid transport, thereby promoting the M2 phenotype polarization of macrophages. ConclusionM-CS-E-LNC exhibited significantly improved bioavailability and water solubility, which translated to greater therapeutic effects on macrophage polarization. Our findings also demonstrate, for the first time, that CPT1 may be a new therapeutic target for SAP treatment.

The Impact of Neonatal Curcumin Intake on Key Molecular Markers in Lipid and Glucose Metabolism

The high prevalence of obesity, resulting from the increased consumption of a fructose-rich diet, poses a serious global threat to children's public health. Obesity is linked to several metabolic disorders, including insulin resistance and type-2 diabetes. Furthermore, type-2 diabetes is characterized by impaired lipid and glucose metabolism. This study investigated the impact of neonatal curcumin intake on the expression of key molecular markers related to liver lipid metabolism [Liver kinase B-1 (LKB-1), AMP-activated protein kinase (AMPK), Carnitine palmitoyltransferase-1 (CPT-1), and Acetyl-coenzyme A carboxylase-1 (ACC-1)] and glucose metabolism [serine/threonine-protein kinase (AKT-1), Glucose transporter-2 (GLUT-2), glycogen phosphorylase (GP), and Phosphoglucomutase (PGM)]. Curcumin, a polyphenolic compound derived from turmeric, is currently under extensive research for its potential therapeutic applications in various diseases. In this study, a metabolic syndrome model was induced in Sprague Dawley rats by feeding them a high fructose diet, with curcumin administered as the treatment. Gene expression was assessed through Real-Time quantitative PCR, and protein expression was analyzed using the western blot technique. The study observed that a high fructose diet led to the upregulation of genes and proteins associated with lipid metabolism, such as AMPK, LKB-1, ACC-1, and CPT-1 in liver tissues. Curcumin treatment reversed these effects, restoring normal lipid metabolism. Additionally, the high fructose diet downregulated the expression of AKT-1 in hepatic insulin signaling, which was counteracted by curcumin. Moreover, the high fructose diet increased hepatic glucose production, as indicated by the upregulation of GP and PGM gene and protein expression, while curcumin treatment suppressed hepatic glucose production by downregulating GP and PGM expression. The findings improve our understanding of curcumin's molecular mechanisms, which are not yet fully understood. They offer further evidence of curcumin's positive effects. Thus, early neonatal consumption of curcumin could be a potential strategy to prevent high fructose diet-induced obesity and related metabolic disorders, including insulin resistance and type-2 diabetes. Lipid and Glucose Metabolism. This project was funded by the North-West University. 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.

Penthorum chinense Pursh extract ameliorates alcohol-related fatty liver disease in mice via the SIRT1/AMPK signaling axis

Penthorum chinense Pursh (P. chinense), a functional food, has been applied to protect the liver against alcohol-related fatty liver disease (ALD) for a long history in China. This study was designed to evaluate the ameliorative activity of the polyphenolic fraction in P. chinense (PGF) depending on the relief of ALD. The ALD mouse model was established by exposing the mice to a Lieber-DeCarli alcohol liquid diet. We found that PGF administration significantly ameliorated alcohol-induced liver injury, steatosis, oxidative stress, and inflammation in mice. Furthermore, Alcohol-increased levels of the critical hepatic lipid synthesis proteins sterol regulatory element binding transcription factor (SREBP-1) and diacylglycerol o-acyltransferase 2 (DGAT2) were attenuated by PGF. Similarly, PGF inhibited the expression of the lipid transport protein very low-density lipoprotein receptor (VLDLR). Interestingly, PGF restored alcohol-inhibited expression of carnitine palmitoyltransferase 1 (CPT1) and peroxisome proliferator-activated receptor alpha (PPARα), essential fatty acid β-oxidation proteins. Mechanistic studies revealed that PGF protects against alcohol-induced hepatocyte injury and lipid deposition via the SIRT1/AMPK signaling pathway. In sum, this research clearly demonstrated the protective effects of PGF against ALD, which was mediated by activating SIRT1/AMPK pathways in hepatocytes. We provide a new theoretical basis for using P. chinense as a functional food in ALD.

Reciprocal Regulation of Cardiac β-Oxidation and Pyruvate Dehydrogenase by Insulin.

The heart alters the rate and relative oxidation of fatty acids and glucose based on availability and energetic demand. Insulin plays a crucial role in this process diminishing fatty acid and increasing glucose oxidation when glucose availability increases. Loss of insulin sensitivity and metabolic flexibility can result in cardiovascular disease. It is therefore important to identify mechanisms by which insulin regulates substrate utilization in the heart. Mitochondrial pyruvate dehydrogenase (PDH) is the key regulatory site for the oxidation of glucose for ATP production. Nevertheless, the impact of insulin on PDH activity has not been fully delineated, particularly in the heart. We sought in vivo evidence that insulin stimulates cardiac PDH and that this process is driven by inhibition of fatty acid oxidation. Mice injected with insulin exhibited dephosphorylation and activation of cardiac PDH. This was accompanied by an increase in the content of malonyl-CoA, an inhibitor of carnitine palmitoyltransferase 1 (CPT1) and, thus, mitochondrial import of fatty acids. Administration of the CPT1 inhibitor oxfenicine was sufficient to activate PDH. Malonyl-CoA is produced by acetyl-CoA carboxylase (ACC). Pharmacologic inhibition or knockout of cardiac ACC diminished insulin-dependent production of malonyl-CoA and activation of PDH. Finally, circulating insulin and cardiac glucose utilization exhibit daily rhythms reflective of nutritional status. We demonstrate that time of day-dependent changes in PDH activity are mediated, in part, by ACC-dependent production of malonyl-CoA. Thus, by inhibiting fatty acid oxidation, insulin reciprocally activates PDH. These studies identify potential molecular targets to promote cardiac glucose oxidation and treat heart disease.

Effects of endurance training under calorie restriction on the metabolic enzyme activity and transporter levels in mouse skeletal muscle and liver

Although endurance training (ET) and calorie restriction (CR) induce metabolic adaptations in skeletal muscle, the interaction of them have yet to be clarified. This study investigated the effects of endurance training with calorie restriction on the metabolic enzyme activity and transporter levels in mouse skeletal muscle and liver. Ten-week-old male ICR mice were fed ad libitum or subjected to 30% CR. The animals were subdivided into sedentary and ET groups. The animals in the ET group performed treadmill running (20 m/min, 30 min) five days a week for five weeks. Respiratory gas analysis during 24 h of rest showed that CR, but not ET, reduced carbohydrate consumption. While ET enhanced hexokinase (HK) activity in the plantaris and soleus muscles, CR decreased HK, phosphofructokinase, and lactate dehydrogenase activities and monocarboxylate transporter (MCT) 4 protein content. Although ET and CR alone increased citrate synthase (CS) activity and MCT1 protein content in the plantaris muscle, no additive or synergistic effects were observed. In the soleus muscle, ET increased CS, β-hydroxyacyl-CoA dehydrogenase (β-HAD), and total carnitine palmitoyltransferase (CPT) activities; however, CR significantly decreased CS and β-HAD activities but enhanced total CPT activity. Additionally, CR enhanced the glucose transporter 4 protein content in the plantaris and soleus muscles. In the liver, CR enhanced the protein levels of glucose 6-phosphatase, fructose 1,6-bisphosphatase, and mitochondrial phosphoenolpyruvate carboxykinase. Moreover, ET partially normalized the CR-induced increase in fatty acid synthase and acetyl-CoA carboxylase. These observations suggest that CR enhances the capacity for glucose and fatty acid synthesis in the liver as well as the glucose and lactate uptake capacity in skeletal muscle while reducing carbohydrate consumption in skeletal muscle. It is suggested that CR partially interferes with skeletal muscle adaptations to ET. This study was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant numbers 20H04071, 21K21249, and 23K16718). 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.

Gene Expression and Ultrastructural Evidence for Metabolic Derangement in the Primary Mitral Regurgitation Heart

Abstract Aims Chronic neurohormonal activation and hemodynamic load cause derangement in myocardial substrate utilization. We test the hypothesis that the primary mitral regurgitation heart (PMR) heart shows altered metabolic gene profile and cardiac ultrastructure consistent with decreased fatty acid and glucose metabolism despite LVEF &amp;gt; 60%. Methods and Results Metabolic gene expression in right atrial (RA), left atrial (LA), and left ventricular (LV) biopsies from donor hearts (n = 10) and from patients with moderate to severe PMR (n = 11) at surgery showed decreased mRNA glucose transporter type 4 (GLUT-4), GLUT-1 and insulin receptor substrate 2 and increased mRNA hexokinase 2, O-linked N-acetylglucosamine transferase and O-GlcNAcase, rate-limiting steps in the hexosamine biosynthetic pathway. Pericardial fluid levels of Neuropeptide Y were 4-fold higher than simultaneous plasma indicative of increased sympathetic drive. Quantitative TEM shows glycogen accumulation, glycophagy, increased lipid droplets, and mitochondrial cristae lysis. These findings are associated with increased mRNA for glycogen synthase kinase 3β, decreased carnitine palmitoyl transferase 2, and fatty acid synthase in PMR vs. normals. Cardiac magnetic resonance/positron emission tomography for 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake showed decreased LV [18F]FDG uptake and increased plasma HbA1c, free fatty acids, mtDAMPs in a separate cohort of stable moderate PMR patients with LVEF &amp;gt; 60% (n = 8) vs. normal controls (n = 8). Conclusions The PMR heart has a global ultrastructural and metabolic gene expression pattern of decreased glucose uptake along with increased glycogen and lipid droplets. Further studies must determine whether this presentation is an adaptation or maladaptation in the PMR heart in the clinical evaluation of PMR.

Impaired Long-Chain Fatty Acid Metabolism in Carnitine Palmitoyltransferase II Knockout Mouse Leads to Chronic Pancreatitis

Background: To support high rates of protein synthesis, pancreatic acinar cells must generate large quantities of ATP. Mitochondrial dysfunction and impaired energy metabolism play a significant role in the development of pancreatitis. Patients with elevated plasma triglycerides are at increased risk for development of severe acute pancreatitis. Carnitine palmitoyltransferase II (CPT2) is required for importing and thus metabolizing long-chain fatty acids (LCFAs) in mitochondria. To inhibit LCFA metabolism, we utilized the CPT2acinarKO mouse to probe the consequences of impaired LCFA import on pancreatic function. Hypothesis: Loss of CPT2 causes an accumulation of long-chain acylcarnitines and disruption of the tissue acylcarnitine/free carnitine ratio which is thought to alter cellular function. Given acinar cells’ high metabolic requirement, impaired LCFA utilization would reduce energy production, secretory function, and alter pancreatic lipid composition. Methods: We generated mice lacking CPT2 specifically in acinar cells (CPT2acinarKO) by crossing tamoxifen-inducible, Elastase-Cre mice with CPT2 floxed mice. Mice were fed a high fat (60% kcal fat), low fat (10% kcal fat), or chow (14% kcal fat) diet for 12 weeks. Analysis of fat accumulation, edema, and fibrosis was performed with H&amp;E and picrosirius staining. Mass Spec. lipid profiling was performed in pancreas and serum. Acinar cells were isolated from wildtype, CPT2 floxed, and CPT2acinarKO mice to assess secretory function, ATP levels, and necrosis via lactate dehydrogenase (LDH) release. Results: Histologic examination revealed CPT2acinarKO mice on all three diets displayed pancreatic fat accumulation. Strikingly, CPT2acinarKO mice fed a chow or low fat diet developed chronic pancreatitis with a 25% loss in pancreatic weight, immune cell infiltration, edema, and fibrosis. As anticipated, long-chain acylcarnitines were significantly elevated in CPT2acinarKO pancreas. Assessment of secretion in 2 weeks post tamoxifen cells revealed significantly reduced maximal (10 pM) and supramaximal (1 nM) cholecystokinin (CCK) stimulated amylase release as a percent of total cellular amylase. Acini isolated at 4 weeks post tamoxifen revealed significantly increased basal secretion and reduced maximal and supramaximal CCK stimulated amylase release. When normalized to cellular DNA, secretion was similar between CPT2acinarKO and CPT2 floxed acinar cells indicating CPT2acinarKO cells had reduced amylase levels. Wildtype acinar cells treated with unsaturated and saturated free fatty acid concentrations as low as 100 μM for 3 hours caused significant necrosis. CPT2acinarKO pancreas had significantly decreased ATP levels indicative of mitochondrial dysfunction. Conclusion: Loss of CPT2 in the pancreatic acinar cells impairs LCFA import, reduces ATP levels, disrupts the secretory pathway, promoting chronic pancreatitis. In contrast to other CPT2 knockout models, pancreatitis occurs independent of high fat feeding in CPT2acinarKO mice. Further investigation is needed to identify metabolic alterations leading to acinar damage and mitochondrial dysfunction following the loss of CPT2. UW-Madison Comprehensive Diabetes Center Pilot Grant. 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.

Effects of Berberine on Lipid Metabolism, Antioxidant Status, and Immune Response in Liver of Tilapia (Oreochromis niloticus) under a High-Fat Diet Feeding.

Berberine, a natural alkaloid found abundantly in various medicinal plants, exhibits antioxidative, anti-inflammatory, and lipid metabolism-regulatory properties. Nonetheless, its protective effects and the molecular mechanisms underlying liver injury in fish have not been fully elucidated. The aims of this study were to investigate the antioxidative, anti-inflammatory, and lipid metabolism-regulating effects of berberine against high-fat diet (HFD)-induced liver damage and to clarify the underlying molecular mechanisms. Tilapia were fed diets containing two doses of berberine (50 and 100 mg/kg diet) alongside high fat for 60 days. The results showed that berberine treatments (50 and/or 100 mg/kg) significantly reduced elevated aminotransferases, triglycerides (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-c) in the plasma. In the liver, berberine treatments significantly increased the expression of peroxisome proliferator-activated receptor α (pparα) and carnitine palmitoyltransferase 1 (cpt-1) genes, leading to a reduction in lipid accumulation. Meanwhile, berberine treatment suppressed lipid peroxidation formation and enhanced antioxidant capacity. Berberine upregulated the mRNA levels of erythroid 2-related factor 2 (nrf2) and its downstream genes including heme oxygenase 1 (ho-1) and glutathione-S-transferase (gstα). Additionally, berberine attenuated the inflammation by inhibiting the expression of toll-like receptor 2 (tlr2), myeloid differential protein-88 (myd88), relb, and inflammatory cytokines such as interleukin-1β (il-1β), tumor necrosis factor-α (tnf-α), and il-8. In summary, this study suggested that berberine offers protection against HFD-induced liver damage in tilapia via regulating lipid metabolism, antioxidant status, and immune response. This protective effect may be attributed to the modulation of the Nrf2, TLR2/MyD88/NF-κB, and PPARα signaling pathways.