Acetyl-CoA carboxylase 2 mutant mice are protected against obesity and diabetes induced by high-fat/high-carbohydrate diets

Lipid metabolism: a central modulator of RORγt-mediated Th17 cell differentiation

Among the T helper cell subsets, Th17 cells contribute to the development of various inflammatory and autoimmune diseases, including psoriasis, rheumatoid arthritis, inflammatory bowel disease, steroid-resistant asthma, and multiple sclerosis. Retinoid-related orphan receptor gamma t (RORγt), a nuclear hormone receptor, serves as a master transcription factor for Th17 cell differentiation. Recent findings have shown that modulating the metabolic pathway is critical for Th17 cell differentiation, particularly through the engagement of de novo lipid biosynthesis. Suppression of lipid biosynthesis, either through the pharmacological inhibition or gene deletion of related enzymes in CD4+ T cells, results in significant impairment of Th17 cell differentiation. Mechanistic studies indicate that metabolic fluxes through both the fatty acid and cholesterol biosynthetic pathways have a pivotal role in the regulation of RORγt activity through the generation of endogenous RORγt lipid ligands. This review discusses recent discoveries highlighting the importance of lipid metabolism in Th17 cell differentiation and function, as well as exploring specific molecular pathways involved in RORγt activation through cellular lipid metabolism. We further elaborate on a pioneering therapeutic approach to improve inflammatory and autoimmune disorders via the inhibition of RORγt.

Leucine Supplementation Modulates Lipid Metabolism and Inflammation in Early Weaning Piglets

Early weaning can induce the programmed dysregulation of glycolipid metabolism and inflammation in adult animals. The primary objective of this study was to evaluate the efficacy of leucine supplementation administered promptly after early weaning in mitigating these adverse effects in piglets. At day 21, 24 piglets were randomly selected and divided into 3 groups: EW group where the piglets were weaned at day 21 and fed basal diet, EWL group where the piglets were weaned at day 21 and fed the basal diet with supplementation of 1% leucine, and C group where the piglets were fed basal diet and weaned at 28 days. Each group contained eight replicates, with one piglet per replicate. The results indicated that early weaning had an impact on gut health and could activate the inhibitor of the kappa B kinase gamma/inhibitor kappa B alpha/NF-kappa-B (IKKγ/IκBα/NF-κB) signaling pathway to ameliorate pro-inflammatory factor and apoptosis levels. Furthermore, early weaning reduced the activity of fatty acid β oxidation (FAβO) and affected genes linked with lipid metabolism. Supplementing with leucine can improve the effects of these factors. In summary, leucine may alleviate the influences of early weaning on the lipid metabolism and inflammation in piglets.

Parental cardiorespiratory fitness influences early life energetics and metabolic health

High cardiorespiratory fitness (CRF) is associated with a reduced risk of metabolic disease and is linked to superior mitochondrial respiratory function. This study investigated how intrinsic CRF affects bioenergetics and metabolic health in adulthood and early life. Adult rats selectively bred for low and high running capacity [low capacity runners (LCR) and high capacity runners (HCR), respectively] underwent metabolic phenotyping before mating. Weanlings were evaluated at 4-6 wk of age, and whole body energetics and behavior were assessed using metabolic cages. Mitochondrial respiratory function was assessed in permeabilized tissues through high-resolution respirometry. Proteomic signatures of adult and weanling tissues were determined using mass spectrometry. The adult HCR group exhibited lower body mass, improved glucose tolerance, and greater physical activity compared with the LCR group. The adult HCR group demonstrated higher mitochondrial respiratory capacities in the soleus and heart compared with the adult LCR group, which coincided with a greater abundance of proteins involved in lipid catabolism. HCR and LCR weanlings had similar body mass, but HCR weanlings displayed reduced adiposity. In addition, HCR weanlings exhibited better glucose tolerance and higher physical activity levels than LCR weanlings. Higher respiratory capacities were observed in the soleus, heart, and liver tissues of HCR weanlings compared with LCR weanlings, which were not owed to greater mitochondrial content. Proteomic analyses indicated a greater potential for lipid oxidation in the contractile muscles of HCR weanlings. In conclusion, offspring born to parents with high CRF possess an enhanced capacity for lipid catabolism and oxidative phosphorylation, thereby influencing metabolic health. These findings highlight that intrinsic CRF shapes the bioenergetic phenotype with implications for metabolic resilience in early life.NEW & NOTEWORTHY Inherited cardiorespiratory fitness (CRF) influences early life bioenergetics and metabolic health. Higher intrinsic CRF was associated with reduced adiposity and improved glucose tolerance in early life. This metabolic phenotype was accompanied by greater mitochondrial respiratory capacity in skeletal muscle, heart, and liver tissue. Proteomic profiling of these three tissues further revealed potential mechanisms linking inherited CRF to early life metabolism.

Partners in diabetes epidemic: A global perspective

There is a recent increase in the worldwide prevalence of both obesity and diabetes. In this review we assessed insulin signaling, genetics, environment, lipid metabolism dysfunction and mitochondria as the major determinants in diabetes and to identify the potential mechanism of gut microbiota in diabetes diseases. We searched relevant articles, which have key information from laboratory experiments, epidemiological evidence, clinical trials, experimental models, meta-analysis and review articles, in PubMed, MEDLINE, EMBASE, Google scholars and Cochrane Controlled Trial Database. We selected 144 full-length articles that met our inclusion and exclusion criteria for complete assessment. We have briefly discussed these associations, challenges, and the need for further research to manage and treat diabetes more efficiently. Diabetes involves the complex network of physiological dysfunction that can be attributed to insulin signaling, genetics, environment, obesity, mitochondria and stress. In recent years, there are intriguing findings regarding gut microbiome as the important regulator of diabetes. Valid approaches are necessary for speeding medical advances but we should find a solution sooner given the burden of the metabolic disorder - What we need is a collaborative venture that may involve laboratories both in academia and industries for the scientific progress and its application for the diabetes control.

Leucine Supplementation Ameliorates Early-Life Programming of Obesity in Rats

The advanced cessation of lactation elevates the risk of programmed obesity and obesity-related metabolic disorders in adulthood. This study used multiomic analysis to investigate the mechanism behind this phenomenon and the effects of leucine supplementation on ameliorating programmed obesity development. Wistar/SD rat offspring were subjected to early weaning (EW) at day 17 (EWWIS and EWSD groups) or normal weaning at day 21 (CWIS and CSD groups). Half of the rats from the EWSD group were selected to create a new group with 2-month leucine supplementation at day 150. The results showed that EW impaired lipid metabolic gene expression and increased insulin, neuropeptide Y, and feed intake, inducing obesity in adulthood. Six lipid metabolism-related genes (Acot1, Acot2, Acot4, Scd, Abcg8, and Cyp8b1) were influenced by EW during the entire experimental period. Additionally, adult early-weaned rats exhibited cholesterol and fatty acid β-oxidation disorders, liver taurine reduction, cholestasis, and insulin and leptin resistance. Leucine supplementation partly alleviated these metabolic disorders and increased liver L-carnitine, retarding programmed obesity development. This study provides new insights into the mechanism of programmed obesity development and the potential benefits of leucine supplementation, which may offer suggestions for life planning and programmed obesity prevention.

ARTICLE HIGHLIGHTS

Early-weaned adult rats showed excess lipid accumulation and metabolic defects. Early weaning disrupts lipid metabolism and secretion of neuropeptide Y and insulin. The altered lipid metabolic gene expression in this study is vital in programming. Leucine mitigates metabolic disorders and hampers programmed obesity development.

The impact of cancer cachexia on gut microbiota composition and short-chain fatty acid metabolism in a murine model

This study investigates the relationship between cancer cachexia and the gut microbiota, focusing on the influence of cancer on microbial composition. Lewis lung cancer cell allografts were used to induce cachexia in mice, and body and muscle weight changes were monitored. Fecal samples were collected for targeted metabolomic analysis for short chain fatty acids and microbiome analysis. The cachexia group exhibited lower alpha diversity and distinct beta diversity in gut microbiota, compared to the control group. Differential abundance analysis revealed higher Bifidobacterium and Romboutsia, but lower Streptococcus abundance in the cachexia group. Additionally, lower proportions of acetate and butyrate were observed in the cachexia group. The study observed that the impact of cancer cachexia on gut microbiota and their generated metabolites was significant, indicating a host-to-gut microbiota axis. [BMB Reports 2023; 56(7): 404-409].

ZFP92, a KRAB domain zinc finger protein enriched in pancreatic islets, binds to B1/Alu SINE transposable elements and regulates retroelements and genes

Repressive KRAB domain-containing zinc-finger proteins (KRAB-ZFPs) are abundant in mammalian genomes and contribute both to the silencing of transposable elements (TEs) and to the regulation of developmental stage- and cell type-specific gene expression. Here we describe studies of zinc finger protein 92 (Zfp92), an X-linked KRAB-ZFP that is highly expressed in pancreatic islets of adult mice, by analyzing global Zfp92 knockout (KO) mice. Physiological, transcriptomic and genome-wide chromatin binding studies indicate that the principal function of ZFP92 in mice is to bind to and suppress the activity of B1/Alu type of SINE elements and modulate the activity of surrounding genomic entities. Deletion of Zfp92 leads to changes in expression of select LINE and LTR retroelements and genes located in the vicinity of ZFP92-bound chromatin. The absence of Zfp92 leads to altered expression of specific genes in islets, adipose and muscle that result in modest sex-specific alterations in blood glucose homeostasis, body mass and fat accumulation. In islets, Zfp92 influences blood glucose concentration in postnatal mice via transcriptional effects on Mafb, whereas in adipose and muscle, it regulates Acacb, a rate-limiting enzyme in fatty acid metabolism. In the absence of Zfp92, a novel TE-Capn11 fusion transcript is overexpressed in islets and several other tissues due to de-repression of an IAPez TE adjacent to ZFP92-bound SINE elements in intron 3 of the Capn11 gene. Together, these studies show that ZFP92 functions both to repress specific TEs and to regulate the transcription of specific genes in discrete tissues.

Uncoupling Lipid Synthesis from Adipocyte Development

Obesity results from the expansion of adipose tissue, a versatile tissue regulating energy homeostasis, adipokine secretion, thermogenesis, and inflammation. The primary function of adipocytes is thought to be lipid storage through lipid synthesis, which is presumably intertwined with adipogenesis. However, during prolonged fasting, adipocytes are depleted of lipid droplets yet retain endocrine function and an instant response to nutrients. This observation led us to question whether lipid synthesis and storage can be uncoupled from adipogenesis and adipocyte function. By inhibiting key enzymes in the lipid synthesis pathway during adipocyte development, we demonstrated that a basal level of lipid synthesis is essential for adipogenesis initiation but not for maturation and maintenance of adipocyte identity. Furthermore, inducing dedifferentiation of mature adipocytes abrogated adipocyte identity but not lipid storage. These findings suggest that lipid synthesis and storage are not the defining features of adipocytes and raise the possibility of uncoupling lipid synthesis from adipocyte development to achieve smaller and healthier adipocytes for the treatment of obesity and related disorders.

Oncolytic avian reovirus σA-modulated fatty acid metabolism through the PSMB6/Akt/SREBP1/acetyl-CoA carboxylase pathway to increase energy production for virus replication

We have demonstrated previously that the σA protein of avian reovirus (ARV) functions as an activator of cellular energy, which upregulates glycolysis and the TCA cycle for virus replication. To date, there is no report with respect to σA-modulated regulation of cellular fatty acid metabolism. This study reveals that the σA protein of ARV inhibits fatty acids synthesis and enhance fatty acid oxidation by upregulating PSMB6, which suppresses Akt, sterol regulatory element-binding protein 1 (SREBP1), acetyl-coA carboxylase α (ACC1), and acetyl-coA carboxylase β (ACC2). SREBP1 is a transcription factor involved in fatty acid and cholesterol biosynthesis. Overexpression of SREBP1 reversed σA-modulated suppression of ACC1 and ACC2. In this work, a fluorescence resonance energy transfer-based genetically encoded indicator, Ateams, was used to study σA-modulated inhibition of fatty acids synthesis which enhances cellular ATP levels in Vero cells and human cancer cell lines (A549 and HeLa). By using Ateams, we demonstrated that σA-modulated inhibition of Akt, SREBP1, ACC1, and ACC2 leads to increased levels of ATP in mammalian and human cancer cells. Furthermore, knockdown of PSMB6 or overexpression of SREBP1 reversed σA-modulated increased levels of ATP in cells, indicating that PSMB6 and SREBP1 play important roles in ARV σA-modulated cellular fatty acid metabolism. Furthermore, we found that σA _R155/273A mutant protein loses its ability to enter the nucleolus, which impairs its ability to regulate fatty acid metabolism and does not increase ATP formation, suggesting that nucleolus entry of σA is critical for regulating cellular fatty acid metabolism to generate more energy for virus replication. Collectively, this study provides novel insights into σA-modulated inhibition of fatty acid synthesis and enhancement of fatty acid oxidation to produce more energy for virus replication through the PSMB6/Akt/SREBP1/ACC pathway.

Uncoupling Proteins in Striated Muscle Tissue: Known Facts and Open Questions

Significance: Uncoupling proteins (UCPs) are a family of proteins that allow proton leakage across the inner mitochondrial membrane. Although UCP1, also known as thermogenin, is well known and important for heat generation in brown adipose tissue, striated muscles express two distinct members of UCP, namely UCP2 and UCP3. Unlike UCP1, the main function of UCP2 and UCP3 does not appear to be heat production. Recent Advances: Interestingly, UCP2 is the main isoform expressed in cardiac tissues, whereas UCP3 is the dominant isoform in skeletal muscles. In the past years, researchers have started to investigate the regulation of UCP2 and UCP3 expression in striated muscles. Furthermore, concepts about the proposed functions of UCP2 and UCP3 in striated muscles are developed but are still a matter of debate. Critical Issues: Potential functions of UCP2 and UCP3 in striated muscles include a role in protection against mitochondria-dependent oxidative stress, as transporter for pyruvate, fatty acids, and protons into and out of the mitochondria, and in metabolic sensing. In this context, the different isoform expression of UCP2 and UCP3 in the skeletal and cardiac muscle may be related to different metabolic requirements of the two organs. Future Directions: The level of expression of UCP2 and UCP3 in striated muscles changes in different disease stages. This suggests that UCPs may become drug targets for therapy in the future. Antioxid. Redox Signal. 37, 324-335.

Reducing ether lipids improves Drosophila overnutrition-associated pathophysiology phenotypes via a switch from lipid storage to beta-oxidation

High-calorie diets increase the risk of developing obesity, cardiovascular disease, type-two diabetes (T2D), and other comorbidities. These "overnutrition" diets also promote the accumulation of a variety of harmful lipids in the heart and other peripheral organs, known as lipotoxicity. However, the mechanisms underlying lipotoxicity and its influence on pathophysiology remain unknown. Our study uses genetics to identify the role of ether lipids, a class of potential lipotoxins, in a Drosophila model of overnutrition. A high-sugar diet (HSD) increases ether lipids and produces T2D-like pathophysiology phenotypes, including obesity, insulin resistance, and cardiac failure. Therefore, we targeted ether lipid biosynthesis through the enzyme dihydroxyacetonephosphate acyltransferase (encoded by the gene DHAPAT). We found that reducing DHAPAT in the fat body improved TAG and glucose homeostasis, cardiac function, respiration, and insulin signaling in flies fed a HSD. The reduction of DHAPAT may cause a switch in molecular signaling from lipogenesis to fatty acid oxidation via activation of a PPARα-like receptor, as bezafibrate produced similar improvements in HS-fed flies. Taken together, our findings suggest that ether lipids may be lipotoxins that reduce fitness during overnutrition.

Ameliorative effects of high intensity interval training and Lactobacillus rhamnosus GG Protect against tetracycline-induced fatty liver in rats: a gene expression profiling comparative study

Exercise training and probiotics have been suggested as a treatment for the prevention of chronic liver damage such as non-alcoholic fatty liver disease (NAFLD). Lactobacillus rhamnosus Gorbach - Goldin (LGG) is one of the most widely used probiotic strains that decreases liver damage. Thus, this study aims to consider the ameliorative effects of high intensity interval training (HIIT) and LGG against tetracycline-induced fatty liver in rats. Eighty male Wistar rats were randomly divided into 8 groups of (n=10 each group): control, LGG, HIIT, LGG+HIIT, NAFLD, NAFLD+LGG, NAFLD+HIIT, and NAFLD+LGG+HIIT. The rats are treated by intraperitoneal injection with 140 mg/kg^-1 tetracycline, an antibiotic previously known to induce steatosis. The exercise training groups performed HIIT 5 days/week for 5 weeks. 10⁷ colony-forming units (cfu) of LGG were gavaged for LGG groups 5 days/week for 5 weeks. Probiotic supplementation in combination with interval training significantly decreased tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) mRNA and matrix metalloproteinase-2 (MMP-2) mRNA in the liver (p<0.05), while the levels of lysosomal acid lipase (LIPA) mRNA was significantly increased compared to NAFLD group. Also, compared with NAFLD group, NAFLD+LGG, NAFLD+HIIT and NAFLD+LGG+HIIT groups showed a significant decrease in hepatic monocyte chemoattractant protein-1 (MCP-1). Compared to LGG and LGG+HIIT groups, all NAFLD groups showed a significant decrease in apolipoprotein C3 (apoc3) in liver tissue (p<0.05). The results suggested that interval exercise with LGG supplementation minimizes cell destruction and inflammation in liver tissue due to NAFLD by improving gene expression profiles.

Chloroquine modulates the sulforaphane anti-obesity mechanisms in a high-fat diet model: Role of JAK-2/ STAT-3/ SOCS-3 pathway

The phytochemical sulforaphane (SFN) has been studied for its potential anti-obesity effect, but neither its molecular targets nor its interaction with the antimalarial drug chloroquine (CQ) has been fully delineated. Therefore, high-fat diet (HFD) obese rats were randomly allocated into one of five groups and were left untreated or gavaged orally with SFN (0.5 or 1 mg/kg), CQ (5 mg/kg), or their combination (0.5/5 mg/kg) for six successive weeks to assess their potential interaction and the enrolled mechanisms. SFN effectively reduced the HFD-induced weight gain, blood glucose, and serum leptin levels, and improved lipid profile. On the molecular level, SFN inhibited the lipogenesis-related enzymes, namely sterol regulatory element-binding protein (SREBP)-1c, fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) in both liver and visceral white adipose tissue (vWAT) of HFD obese rats. SFN also turned off the inflammatory pathway conserved Janus kinase/signaling transducers and activators of transcription/suppressor of cytokine signaling (JAK-2/STAT-3/SOCS-3) in these tissues, as well as the inflammatory markers nuclear factor-kappa (NF-κ) B and interleukin (IL)-22 in serum. In contrast, SFN downregulated the gene expression of microRNA (miR-200a), while significantly increasing the autophagic parameters; viz., beclin-1, autophagy-related protein (ATG)-7, and microtubule-associated protein 2 light chain 3 (LC3-II) in both liver and vWAT. On most of the parameters mentioned above, treatment with CQ solely produced a satisfactory effect and intensified the low dose of SFN in the combination regimen. These findings demonstrated the beneficial effects of using CQ as an add-on anti-obesity medicine to SFN.

Transcriptional Integration of Distinct Microbial and Nutritional Signals by the Small Intestinal Epithelium

BACKGROUND & AIMS

The intestine constantly interprets and adapts to complex combinations of dietary and microbial stimuli. However, the transcriptional strategies by which the intestinal epithelium integrates these coincident sources of information remain unresolved. We recently found that microbiota colonization suppresses epithelial activity of hepatocyte nuclear factor 4 nuclear receptor transcription factors, but their integrative regulation was unknown.

METHODS

We compared adult mice reared germ-free or conventionalized with a microbiota either fed normally or after a single high-fat meal. Preparations of unsorted jejunal intestinal epithelial cells were queried using lipidomics and genome-wide assays for RNA sequencing and ChIP sequencing for the activating histone mark H3K27ac and hepatocyte nuclear factor 4 alpha.

RESULTS

Analysis of lipid classes, genes, and regulatory regions identified distinct nutritional and microbial responses but also simultaneous influence of both stimuli. H3K27ac sites preferentially increased by high-fat meal in the presence of microbes neighbor lipid anabolism and proliferation genes, were previously identified intestinal stem cell regulatory regions, and were not hepatocyte nuclear factor 4 alpha targets. In contrast, H3K27ac sites preferentially increased by high-fat meal in the absence of microbes neighbor targets of the energy homeostasis regulator peroxisome proliferator activated receptor alpha, neighbored fatty acid oxidation genes, were previously identified enterocyte regulatory regions, and were hepatocyte factor 4 alpha bound.

CONCLUSIONS

Hepatocyte factor 4 alpha supports a differentiated enterocyte and fatty acid oxidation program in germ-free mice, and that suppression of hepatocyte factor 4 alpha by the combination of microbes and high-fat meal may result in preferential activation of intestinal epithelial cell proliferation programs. This identifies potential transcriptional mechanisms for intestinal adaptation to multiple signals and how microbiota may modulate intestinal lipid absorption, epithelial cell renewal, and systemic energy balance.

Acetyl-coenzyme A carboxylase beta gene polymorphism does not predict cardiovascular risk susceptibility in Chinese type 2 diabetic individuals

AIM

Type 2 diabetes (T2D) is associated with significant cardiovascular (CV) morbidity and mortality. A single-nucleotide polymorphism (SNP) in the acetyl-coenzyme A carboxylase beta (ACACB) gene, rs2268388, reproducibly associates with diabetic nephropathy (DN). ACACB regulates fatty-acid oxidation. As such, we assessed whether ACACB SNP rs2268388 was associated with CV disease in Chinese individuals with T2D.

METHODS

Chinese individuals with T2D were genotyped for SNP rs2268388. Baseline demographics were recorded and clinical data regarding coronary, carotid, and peripheral arterial disease and congestive heart failure were retrieved from electronic patient records. Statistical analyses were performed to detect associations between the rs2268388 T risk allele with CV outcomes in the cohort.

RESULTS

A total of 596 Chinese individuals with T2D were genotyped. Their mean age was 66.8 ± 10.9 years at the time of data extraction. Genotyping revealed 59.7%, 33.2% and 7.1% of the study population were non-carriers, heterozygous and homozygous carriers of the rs2268388 T risk allele in ACACB. No statistically significant correlations of the risk allele were observed with CV outcomes.

CONCLUSION

These results did not demonstrate association between rs2268388 SNP in ACACB with CV outcomes in Chinese T2D patients. The ACACB gene and its role in CV risk susceptibility, via alterations in fatty acid oxidation, remains an interesting postulate and studies with larger cohort sizes and in different ethnic groups remain warranted.

Analysis of differentially expressed proteins between HER2 positive and triple negative breast cancer and their prognostic significance

Both triple negative breast cancer (TNBA) and HER2-positive breast cancer lack expression of estrogen receptor alpha (ER) and progesterone receptor (PR), while human epidermal growth factor receptor 2 (HER2) in TNBC is also negative. This study aimed to identify the differentially expressed proteins (DEPs) between TNBC and HER2-positive breast cancer and to improve understanding of their role in the prognosis of breast cancer. By analyzing the breast cancer data set in The Cancer Proteome Atlas (TCPA) database, 15 DEPs between TNBC and HER2-positive breast cancer were identified. GO and pathway enrichment analysis were performed on DEPs, and the protein-protein interaction (PPI) network was constructed. The overall survival (OS) analysis of the breast cancer protein dataset in the Kaplan-Meier plotter showed that low expression of ACC1 suggested a higher OS of HER2-positive breast cancer (HR = 5.34, P < 0.05) and TNBC (HR = 2.88, P < 0.05). And TNBC patients with high TBA1B (HR = 0.16, P < 0.01) or low INPP4B (HR = 3.47, P < 0.05) expression have a better prognosis. Our research provides new insights into the prognostic indicators of TNBC and HER2-positive breast cancer, which could be further studied.

Selective acetyl-CoA carboxylase 1 inhibitor improves hepatic steatosis and hepatic fibrosis in a pre-clinical NASH model

Acetyl-CoA carboxylase (ACC) 1 and ACC2 are essential rate-limiting enzymes that synthesize malonyl-CoA (M-CoA) from acetyl-CoA. ACC1 is predominantly expressed in lipogenic tissues and regulates the de novo lipogenesis (DNL) flux. It is upregulated in the liver of patients with nonalcoholic fatty liver disease (NAFLD), ultimately leading to the formation of fatty liver. Therefore, selective ACC1 inhibitors may prevent the pathophysiology of NAFLD and nonalcoholic steatohepatitis (NASH) by reducing hepatic fat, inflammation, and fibrosis. Many studies have suggested ACC1/2 dual inhibitors for treating NAFLD/NASH; however, reports on selective ACC1 inhibitors are lacking. In this study, we investigated the effects of compound-1, a selective ACC1 inhibitor for treating NAFLD/NASH, using pre-clinical in vitro and in vivo models. Compound-1 reduced M-CoA content and inhibited the incorporation of [¹⁴C] acetate into fatty acids in HepG2 cells. Additionally, it reduced hepatic M-CoA content and inhibited DNL in C57BL/6J mice after a single dose. Further, compound-1 treatment for 8 weeks in western diet-fed melanocortin 4 receptor (MC4R) knockout mice-NAFLD/NASH mouse model-improved liver hypertrophy and reduced hepatic triglyceride content. The reduction of hepatic M-CoA by the selective ACC1 inhibitor was highly correlated with reduction in hepatic steatosis and fibrosis. These findings support further investigations of the use of this ACC1 inhibitor as a new treatment for NFLD/NASH. Significance Statement This is the first study to demonstrate that a novel selective inhibitor of acetyl-CoA carboxylase 1 (ACC1) has anti-nonalcoholic fatty liver disease (NAFLD) and anti-nonalcoholic steatohepatitis (NASH) effects in pre-clinical models. Treatment with this compound significantly improved hepatic steatosis and fibrosis in a mouse model. These findings support the use of this ACC1 inhibitor as a new treatment for NAFLD/NASH.

Sequencing, Expression, and Functional Analyses of Four Genes Related to Fatty Acid Biosynthesis During the Diapause Process in the Female Ladybird, Coccinella septempunctata L

The ladybird Coccinella septempunctata L., a predatory insect, serves as an excellent biological control agent against common agricultural pests. It undergoes a diapause phenomenon, during which a large amount of fat accumulates in the abdomen. A comprehensive analysis of this lipid accumulation can reveal the molecular mechanisms underlying diapause regulation, which can be exploited to improve the shipping and transport of the insect for agricultural applications. In this study, we compared the transcriptome of C. septempunctata during non-diapause, diapause, and post-diapause and screened four key genes related to lipid metabolism. The cDNA of these four relevant enzymes, acetyl-CoA carboxylase (ACC), long-chain fatty acid-CoA ligase (ACSL), elongase of very-long-chain fatty acids (ELO), and very-long-chain 3-oxoacyl-CoA reductase (KAR), were cloned using reverse transcription-polymerase chain reaction and rapid amplification of cDNA ends. Their expression profiles were analyzed during the preparation and maintenance phases of diapause and the post-diapause phase. The functions of these four key enzymes in diapause were further verified using RNA interference. All four genes were most closely related to the homeotic gene from Tribolium castaneum. The expression profiles of these four genes were significantly affected under diapause-inducing conditions; their expression level was the highest in the diapause preparation phase, and it gradually decreased with the diapause induction time. RNA interference showed that the target genes play important roles in fat storage during early diapause, and the decrease in their expression leads to a decrease in lipid content in C. septempunctata. These results indicate an important role of ACC, ACSL, ELO, and KAR in lipid accumulation. Our findings could help elucidate the production and accumulation of lipids by insects during the preparation for diapause and improve biological control.

Atherosclerosis Impairs Naive CD4 T-Cell Responses via Disruption of Glycolysis

Objective

CD4 T cells are important regulators of atherosclerotic progression. The metabolic profile of CD4 T cells controls their signaling and function, but how atherosclerosis affects T-cell metabolism is unknown. Here, we sought to determine the impact of atherosclerosis on CD4 T-cell metabolism and the contribution of such metabolic alterations to atheroprogression.

Approach and Results

Using PCR arrays, we profiled the expression of metabolism genes in CD4 T cells from atherosclerotic apolipoprotein-E knockout mice fed a Western diet. These cells exhibited dysregulated expression of genes critically involved in glycolysis and fatty acid degradation, compared with those from animals fed a standard laboratory diet. We examined how T-cell metabolism was changed in either Western diet–fed apolipoprotein-E knockout mice or samples from patients with cardiovascular disease by measuring glucose uptake, activation, and proliferation in CD4 T cells. We found that naive CD4 T cells from Western diet–fed apolipoprotein-E knockout mice failed to uptake glucose and displayed impaired proliferation and activation, compared with CD4 T cells from standard laboratory diet–fed animals. Similarly, we observed that naive CD4 T-cell frequencies were reduced in the circulation of human subjects with high cardiovascular disease compared with low cardiovascular disease. Naive T cells from high cardiovascular disease subjects also showed reduced proliferative capacity.

Conclusions

These results highlight the dysfunction that occurs in CD4 T-cell metabolism and immune responses during atherosclerosis. Targeting metabolic pathways within naive CD4 T cells could thus yield novel therapeutic approaches for improving CD4 T-cell responses against atheroprogression.

Identification of Long Non-Coding RNAs Involved in Porcine Fat Deposition Using Two High-Throughput Sequencing Methods

Adipose is an important body tissue in pigs, and fatty traits are critical in pig production. The function of long non-coding RNA (lncRNA) in fat deposition and metabolism has been found in previous studies. In this study, we collected the adipose tissue of six Landrace pigs with contrast backfat thickness (n_high = 3, n_low = 3), after which we performed strand-specific RNA sequencing (RNA-seq) based on pooling and biological replicate methods. Biological replicate and pooling RNA-seq revealed 1870 and 1618 lncRNAs, respectively. Using edgeR, we determined that 1512 genes and 220 lncRNAs, 2240 genes and 127 lncRNAs were differentially expressed in biological replicate and pooling RNA-seq, respectively. After target gene prediction, we found that ACSL3 was cis-targeted by lncRNA TCONS-00052400 and could activate the conversion of long-chain fatty acids. In addition, lncRNA TCONS_00041740 cis-regulated gene ACACB regulated the rate-limiting enzyme in fatty acid oxidation. Since these genes have necessary functions in fat metabolism, the results imply that the lncRNAs detected in our study may affect backfat deposition in swine through regulation of their target genes. Our study explored the regulation of lncRNA and their target genes in porcine backfat deposition and provided new insights for further investigation of the biological functions of lncRNA.

High Fat Activates O-GlcNAcylation and Affects AMPK/ACC Pathway to Regulate Lipid Metabolism

A high-fat diet often leads to excessive fat deposition and adversely affects the organism. However, the mechanism of liver fat deposition induced by high fat is still unclear. Therefore, this study aimed at acetyl-CoA carboxylase (ACC) to explore the mechanism of excessive liver deposition induced by high fat. In the present study, the ORF of ACC1 and ACC2 were cloned and characterized. Meanwhile, the mRNA and protein of ACC1 and ACC2 were increased in liver fed with a high-fat diet (HFD) or in hepatocytes incubated with oleic acid (OA). The phosphorylation of ACC was also decreased in hepatocytes incubated with OA. Moreover, AICAR dramatically improved the phosphorylation of ACC, and OA significantly inhibited the phosphorylation of the AMPK/ACC pathway. Further experiments showed that OA increased global O-GlcNAcylation and agonist of O-GlcNAcylation significantly inhibited the phosphorylation of AMPK and ACC. Importantly, the disorder of lipid metabolism caused by HFD or OA could be rescued by treating CP-640186, the dual inhibitor of ACC1 and ACC2. These observations suggested that high fat may activate O-GlcNAcylation and affect the AMPK/ACC pathway to regulate lipid synthesis, and also emphasized the importance of the role of ACC in lipid homeostasis.

Genetically increasing flux through β-oxidation in skeletal muscle increases mitochondrial reductive stress and glucose intolerance

Elevated mitochondrial hydrogen peroxide (H₂O₂) emission and an oxidative shift in cytosolic redox environment have been linked to high-fat-diet-induced insulin resistance in skeletal muscle. To test specifically whether increased flux through mitochondrial fatty acid oxidation, in the absence of elevated energy demand, directly alters mitochondrial function and redox state in muscle, two genetic models characterized by increased muscle β-oxidation flux were studied. In mice overexpressing peroxisome proliferator-activated receptor-α in muscle (MCK-PPARα), lipid-supported mitochondrial respiration, membrane potential (ΔΨ_m), and H₂O₂ production rate (JH₂O₂) were increased, which coincided with a more oxidized cytosolic redox environment, reduced muscle glucose uptake, and whole body glucose intolerance despite an increased rate of energy expenditure. Similar results were observed in lipin-1-deficient, fatty-liver dystrophic mice, another model characterized by increased β-oxidation flux and glucose intolerance. Crossing MCAT (mitochondria-targeted catalase) with MCK-PPARα mice normalized JH₂O₂ production, redox environment, and glucose tolerance, but surprisingly, both basal and absolute insulin-stimulated rates of glucose uptake in muscle remained depressed. Also surprising, when placed on a high-fat diet, MCK-PPARα mice were characterized by much lower whole body, fat, and lean mass as well as improved glucose tolerance relative to wild-type mice, providing additional evidence that overexpression of PPARα in muscle imposes more extensive metabolic stress than experienced by wild-type mice on a high-fat diet. Overall, the findings suggest that driving an increase in skeletal muscle fatty acid oxidation in the absence of metabolic demand imposes mitochondrial reductive stress and elicits multiple counterbalance metabolic responses in an attempt to restore bioenergetic homeostasis.NEW & NOTEWORTHY Prior work has suggested that mitochondrial dysfunction is an underlying cause of insulin resistance in muscle because it limits fatty acid oxidation and therefore leads to the accumulation of cytotoxic lipid intermediates. The implication has been that therapeutic strategies to accelerate β-oxidation will be protective. The current study provides evidence that genetically increasing flux through β-oxidation in muscle imposes reductive stress that is not beneficial but rather detrimental to metabolic regulation.

Lipoprotein Lipase Overexpression in Skeletal Muscle Attenuates Weight Regain by Potentiating Energy Expenditure

Moderate weight loss improves numerous risk factors for cardiometabolic disease; however, long-term weight loss maintenance (WLM) is often thwarted by metabolic adaptations that suppress energy expenditure and facilitate weight regain. Skeletal muscle has a prominent role in energy homeostasis; therefore, we investigated the effect of WLM and weight regain on skeletal muscle in rodents. In skeletal muscle of obesity-prone rats, WLM reduced fat oxidative capacity and downregulated genes involved in fat metabolism. Interestingly, even after weight was regained, genes involved in fat metabolism were also reduced. We then subjected mice with skeletal muscle lipoprotein lipase overexpression (mCK-hLPL), which augments fat metabolism, to WLM and weight regain and found that mCK-hLPL attenuates weight regain by potentiating energy expenditure. Irrespective of genotype, weight regain suppressed dietary fat oxidation and downregulated genes involved in fat metabolism in skeletal muscle. However, mCK-hLPL mice oxidized more fat throughout weight regain and had greater expression of genes involved in fat metabolism and lower expression of genes involved in carbohydrate metabolism during WLM and regain. In summary, these results suggest that skeletal muscle fat oxidation is reduced during WLM and regain, and therapies that improve skeletal muscle fat metabolism may attenuate rapid weight regain.

PHD3 Loss Promotes Exercise Capacity and Fat Oxidation in Skeletal Muscle

Rapid alterations in cellular metabolism allow tissues to maintain homeostasis during changes in energy availability. The central metabolic regulator acetyl-CoA carboxylase 2 (ACC2) is robustly phosphorylated during cellular energy stress by AMP-activated protein kinase (AMPK) to relieve its suppression of fat oxidation. While ACC2 can also be hydroxylated by prolyl hydroxylase 3 (PHD3), the physiological consequence thereof is poorly understood. We find that ACC2 phosphorylation and hydroxylation occur in an inverse fashion. ACC2 hydroxylation occurs in conditions of high energy and represses fatty acid oxidation. PHD3-null mice demonstrate loss of ACC2 hydroxylation in heart and skeletal muscle and display elevated fatty acid oxidation. Whole body or skeletal muscle-specific PHD3 loss enhances exercise capacity during an endurance exercise challenge. In sum, these data identify an unexpected link between AMPK and PHD3, and a role for PHD3 in acute exercise endurance capacity and skeletal muscle metabolism.

MAPK-interacting kinase 2 (MNK2) regulates adipocyte metabolism independently of its catalytic activity

The mitogen-activated protein kinase (MAPK)-interacting kinases (MNKs) are serine/threonine protein kinases that are activated by the ERK1/2 (extracellular regulated kinase) and p38α/β MAPK pathways. The MNKs have previously been implicated in metabolic disease and shown to mediate diet-induced obesity. In particular, knockout of MNK2 in mice protects from the weight gain induced by a high-fat diet. These and other data suggest that MNK2 regulates the expansion of adipose tissue (AT), a stable, long-term energy reserve that plays an important role in regulating whole-body energy homeostasis. Using the well-established mouse 3T3-L1 in vitro model of adipogenesis, the role of the MNKs in adipocyte differentiation and lipid storage was investigated. Inhibition of MNK activity using specific inhibitors failed to impair adipogenesis or lipid accumulation, suggesting that MNK activity is not required for adipocyte differentiation and does not regulate lipid storage. However, small-interfering RNA (siRNA) knock-down of MNK2 did reduce lipid accumulation and regulated the levels of two major lipogenic transcriptional regulators, ChREBP (carbohydrate response element-binding protein) and LPIN1 (Lipin-1). These factors are responsible for controlling the expression of genes for proteins involved in de novo lipogenesis and triglyceride synthesis. The knock-down of MNK2 also increased the expression of hormone-sensitive lipase which catalyses the breakdown of triglyceride. These findings identify MNK2 as a regulator of adipocyte metabolism, independently of its catalytic activity, and reveal some of the mechanisms by which MNK2 drives AT expansion. The development of an MNK2-targeted therapy may, therefore, be a useful intervention for reducing weight caused by excessive nutrient intake.

Evaluation of the Relationship between Adipose Metabolism Patterns and Secretion of Appetite-Related Endocrines on Chicken

Simple Summary

The weight of an animal conforms to a certain growth pattern. Among others, feed, environment, and body composition, in addition to genetics, affect the animal’s feed consumption and body weight. Under normal circumstances, the body weight of an animal is mainly affected by feed intake, and body composition may significantly influence feed intake. Therefore, this report sets out the effects of fat accumulation on lipid metabolism and appetite, and finally introduces the effects of feeding patterns on animal feed intake.

Abstract

In addition to the influence of genes, the quality of poultry products is mainly controlled by the rearing environment or feed composition during rearing, and has to meet human use and economical needs. As the only source of energy for poultry, feed considerably affects the metabolic pattern of poultry and further affects the regulation of appetite-related endocrine secretion in poultry. Under normal circumstances, the accumulation of lipid in adipose reduces feed intake in poultry and increases the rate of adipose metabolism. When the adipose content in cells decreases, endocrines that promote food intake are secreted and increase nutrient concentrations in serum and cells. By regulating the balance between appetite and adipose metabolism, the poultry’s growth and posture can maintain a balanced state. In addition, increasing fiber composition in feed can effectively increase poultry welfare, body weight, lean composition and antioxidant levels in poultry. According to this, the concept that proper fiber content should be added to feed should be considered for better economic benefits, poultry welfare and meat productivity.

Liver CPT1A gene therapy reduces diet-induced hepatic steatosis in mice and highlights potential lipid biomarkers for human NAFLD

The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased drastically due to the global obesity pandemic but at present there are no approved therapies. Here, we aimed to revert high-fat diet (HFD)-induced obesity and NAFLD in mice by enhancing liver fatty acid oxidation (FAO). Moreover, we searched for potential new lipid biomarkers for monitoring liver steatosis in humans. We used adeno-associated virus (AAV) to deliver a permanently active mutant form of human carnitine palmitoyltransferase 1A (hCPT1AM), the key enzyme in FAO, in the liver of a mouse model of HFD-induced obesity and NAFLD. Expression of hCPT1AM enhanced hepatic FAO and autophagy, reduced liver steatosis, and improved glucose homeostasis. Lipidomic analysis in mice and humans before and after therapeutic interventions, such as hepatic AAV9-hCPT1AM administration and RYGB surgery, respectively, led to the identification of specific triacylglyceride (TAG) specie (C50:1) as a potential biomarker to monitor NAFFLD disease. To sum up, here we show for the first time that liver hCPT1AM gene therapy in a mouse model of established obesity, diabetes, and NAFLD can reduce HFD-induced derangements. Moreover, our study highlights TAG (C50:1) as a potential noninvasive biomarker that might be useful to monitor NAFLD in mice and humans.

Metformin inhibits intracranial aneurysm formation and progression by regulating vascular smooth muscle cell phenotype switching via the AMPK/ACC pathway

Background

The regulation of vascular smooth muscle cell (VSMC) phenotype plays an important role in intracranial aneurysm (IA) formation and progression. However, the underlying mechanism remains unclear. Metformin is a 5′ AMP-activated protein kinase (AMPK) agonist that has a protective effect on vasculature. The present study investigated whether metformin modulates VSMC phenotype switching via the AMPK/acetyl-CoA carboxylase (ACC) pathway during IA pathogenesis.

Methods

Adult male Sprague-Dawley rats (n = 80) were used to establish an elastase-induced IA model. The effects of metformin on AMPK activation and VSMC phenotype modulation were examined. We also established a platelet-derived growth factor (PDGF)-BB-induced VSMC model and analyzed changes in phenotype including proliferation, migration, and apoptosis as well as AMPK/ACC axis activation under different doses of metformin, AMPK antagonist, ACC antagonist, and their combinations.

Results

Metformin decreased the incidence and rupture rate of IA in the rat model and induced a switch in VSMC phenotype from contractile to synthetic through activation of the AMPK/ACC pathway, as evidenced by upregulation of VSMC-specific genes and decreased levels of pro-inflammatory cytokines. AMPK/ACC axis activation inhibited the proliferation, migration, and apoptosis of VSMCs, in which phenotypic switching was induced by PDGF-BB.

Conclusions

Metformin protects against IA formation and rupture by inhibiting VSMC phenotype switching and proliferation, migration, and apoptosis. Thus, metformin has therapeutic potential for the prevention of IA.

High manganese exposure decreased the risk of high triglycerides in workers: a cross-sectional study

Background

Manganese (Mn) participates in lipid metabolism. However, the associations between Mn exposure and dyslipidaemia is unclear.

Methods

This was a cross-sectional study. Data were collected from the 2017 the Mn-exposed workers healthy cohort (MEWHC). Finally, 803 occupationally Mn-exposed workers included in the study. The workers were divided into two groups. The grouping of this study was based on Mn-Time Weighted Averages (Mn-TWA). The high-exposure group included participants with Mn-TWA greater than 0.15 mg/m³. The low-exposure group included participants with Mn-TWA less than or equal to 0.15 mg/m³. Mn-TWA levels and dyslipidaemia were assessed.

Results

After adjustment for seniority, sex, cigarette consumption, alcohol consumption, high-fat diet frequency, medicine intake in the past two weeks, egg intake frequency, drinking tea, WHR, and hypertension, Mn-TWA levels was negatively correlated with high triglycerides (TG) risk in workers overall (OR = 0.51; 95% CI: 0.36, 0.73; p <  0.01). The results of males and females were consistent (OR = 0.53; 95% CI: 0.34, 0.81; p <  0.01) and (OR = 0.47; 95% CI: 0.24, 0.94; p <  0.01), respectively. By performing interactions analyses of workers overall, we observed no significant interactions among confounders. Mn-TWA levels and pack-years on high TG risk (relative excess risk for the interactions (RERI = 2.29, 95% CI: − 2.07, 6.66), (RERI) = 2.98, 95% CI: − 2.30, 8.26). Similarly, smoking status, drinking status, high-fat diet frequency, and Waist-to-Hip Ratio (WHR) showed non-significant interactions with Mn-TWA levels on high TG risk.

Conclusions

This research indicates that high Mn exposure was negatively related to high TG risk in workers.

Cutting fuel offers new clues in diabetic mystery

Competing theories have held opposite views on the role of flux through β-oxidation in causing insulin resistance. New transcriptomics, proteomics, and metabolomics data of skeletal muscle from mice in which lipid oxidation is limited by restricting entry of fat into mitochondria reveal extensive remodeling of metabolic pathways, consistent with an overall reduction in metabolic efficiency and improved metabolic health. These findings point to a potential new therapeutic approach for treating insulin resistance and type 2 diabetes.

Alterations in Glucose Metabolism During the Transition to Heart Failure: The Contribution of UCP-2

The cardiac expression of the mitochondrial uncoupling protein (UCP)-2 is increased in patients with heart failure. However, the underlying causes as well as the possible consequences of these alterations during the transition from hypertrophy to heart failure are still unclear. To investigate the role of UCP-2 mechanistically, expression of UCP-2 was silenced by small interfering RNA in adult rat ventricular cardiomyocytes. We demonstrate that a downregulation of UCP-2 by siRNA in cardiomyocytes preserves contractile function in the presence of angiotensin II. Furthermore, silencing of UCP-2 was associated with an upregulation of glucose transporter type (Glut)-4, increased glucose uptake, and reduced intracellular lactate levels, indicating improvement of the oxidative glucose metabolism. To study this adaptation in vivo, spontaneously hypertensive rats served as a model for cardiac hypertrophy due to pressure overload. During compensatory hypertrophy, we found low UCP-2 levels with an upregulation of Glut-4, while the decompensatory state with impaired function was associated with an increase of UCP-2 and reduced Glut-4 expression. By blocking the aldosterone receptor with spironolactone, both cardiac function as well as UCP-2 and Glut-4 expression levels of the compensated phase could be preserved. Furthermore, we were able to confirm this by left ventricular (LV) biopsies of patients with end-stage heart failure. The results of this study show that UCP-2 seems to impact the cardiac glucose metabolism during the transition from hypertrophy to failure by affecting glucose uptake through Glut-4. We suggest that the failing heart could benefit from low UCP-2 levels by improving the efficiency of glucose oxidation. For this reason, UCP-2 inhibition might be a promising therapeutic strategy to prevent the development of heart failure.

Recent development in acetyl-CoA carboxylase inhibitors and their potential as novel drugs

Acetyl-CoA carboxylase (ACC), a critical enzyme in the regulation of fatty acid synthesis and metabolism, has emerged as an attractive target for a plethora of emerging diseases, such as diabetes mellitus, nonalcoholic fatty liver disease, cancer, bacterial infections and so on. With decades of efforts in medicinal chemistry, significant progress has been made toward the design and discovery of a considerable number of inhibitors of this enzyme. In this review, we not only clarify the role of ACC in emerging diseases, but also summarize recent developments of potent ACC inhibitors and discuss their molecular mechanisms of action and potentials as novel drugs as well as future perspectives toward the design and discovery of novel ACC inhibitors.

Acetyl-CoA carboxylase 1 and 2 inhibition ameliorates steatosis and hepatic fibrosis in a MC4R knockout murine model of nonalcoholic steatohepatitis

Acetyl-CoA carboxylase (ACC) catalyzes the rate-limiting step in de novo lipogenesis, which is increased in the livers of patients with nonalcoholic steatohepatitis. GS-0976 (firsocostat), an inhibitor of isoforms ACC1 and ACC2, reduced hepatic steatosis and serum fibrosis biomarkers such as tissue inhibitor of metalloproteinase 1 in patients with nonalcoholic steatohepatitis in a randomized controlled trial, although the impact of this improvement on fibrosis has not fully been evaluated in preclinical models. Here, we used Western diet-fed melanocortin 4 receptor-deficient mice that have similar phenotypes to nonalcoholic steatohepatitis patients including progressively developed hepatic steatosis as well as fibrosis. We evaluated the effects of ACC1/2 inhibition on hepatic fibrosis. After the confirmation of significant hepatic fibrosis with a 13-week pre-feeding, GS-0976 (4 and 16 mg/kg/day) treatment for 9 weeks lowered malonyl-CoA and triglyceride content in the liver and improved steatosis, histologically. Furthermore, GS-0976 reduced the histological area of hepatic fibrosis, hydroxyproline content, mRNA expression level of type I collagen in the liver, and plasma tissue metalloproteinase inhibitor 1, suggesting an improvement of hepatic fibrosis. The treatment with GS-0976 was also accompanied by reductions of plasma ALT and AST levels. These data demonstrate that improvement of hepatic lipid metabolism by ACC1/2 inhibition could be a new option to suppress fibrosis progression as well as to improve hepatic steatosis in nonalcoholic steatohepatitis.

A butanolic fraction from the standardized stem extract of Cassia occidentalis L delivered by a self-emulsifying drug delivery system protects rats from glucocorticoid-induced osteopenia and muscle atrophy

We recently reported that a butanol soluble fraction from the stem of Cassia occidentalis (CSE-Bu) consisting of osteogenic compounds mitigated methylprednisone (MP)-induced osteopenia in rats, albeit failed to afford complete protection thus leaving a substantial scope for further improvement. To this aim, we prepared an oral formulation that was a lipid-based self-nano emulsifying drug delivery system (CSE-BuF). The globule size of CSE-BuF was in the range of 100–180 nm of diluted emulsion and the zeta potential was −28 mV. CSE-BuF enhanced the circulating levels of five osteogenic compounds compared to CSE-Bu. CSE-BuF (50 mg/kg) promoted bone regeneration at the osteotomy site and completely prevented MP-induced loss of bone mass and strength by concomitant osteogenic and anti-resorptive mechanisms. The MP-induced downregulations of miR29a (the positive regulator of the osteoblast transcription factor, Runx2) and miR17 and miR20a (the negative regulators of the osteoclastogenic cytokine RANKL) in bone was prevented by CSE-BuF. In addition, CSE-BuF protected rats from the MP-induced sarcopenia and/or muscle atrophy by downregulating the skeletal muscle atrogenes, adverse changes in body weight and composition. CSE-BuF did not impact the anti-inflammatory effect of MP. Our preclinical study established CSE-BuF as a prophylactic agent against MP-induced osteopenia and muscle atrophy.

Structures, functions, and mechanisms of filament forming enzymes: a renaissance of enzyme filamentation

Filament formation by non-cytoskeletal enzymes has been known for decades, yet only relatively recently has its wide-spread role in enzyme regulation and biology come to be appreciated. This comprehensive review summarizes what is known for each enzyme confirmed to form filamentous structures in vitro, and for the many that are known only to form large self-assemblies within cells. For some enzymes, studies describing both the in vitro filamentous structures and cellular self-assembly formation are also known and described. Special attention is paid to the detailed structures of each type of enzyme filament, as well as the roles the structures play in enzyme regulation and in biology. Where it is known or hypothesized, the advantages conferred by enzyme filamentation are reviewed. Finally, the similarities, differences, and comparison to the SgrAI endonuclease system are also highlighted.

Transcriptomic response to changing ambient phosphorus in the marine dinoflagellate Prorocentrum donghaiense

Dinoflagellates represent major contributors to the harmful algal blooms in the oceans. Phosphorus (P) is an essential macronutrient that limits the growth and proliferation of dinoflagellates. However, the specific molecular mechanisms involved in the P acclimation of dinoflagellates remain poorly understood. Here, the transcriptomes of a dinoflagellate Prorocentrum donghaiense grown under inorganic P-replete, P-deficient, and inorganic- and organic P-resupplied conditions were compared. Genes encoding low- and high-affinity P transporters were significantly down-regulated in the P-deficient cells, while organic P utilization genes were significantly up-regulated, indicating strong ability of P. donghaiense to utilize organic P. Up-regulation of membrane phospholipid catabolism and endocytosis provided intracellular and extracellular organic P for the P-deficient cells. Physiological responses of P. donghaiense to dissolved inorganic P (DIP) or dissolved organic P (DOP) resupply exhibited insignificant differences. However, the corresponding transcriptomic responses significantly differed. Although the expression of multiple genes was significantly altered after DIP resupplementation, few biological processes varied. In contrast, various metabolic processes associated with cell growth, such as translation, transport, nucleotide, carbohydrate and lipid metabolisms, were significantly altered in the DOP-resupplied cells. Our results indicated that P. donghaiense evolved diverse DOP utilization strategies to adapt to low P environments, and that DOPs might play critical roles in the P. donghaiense bloom formation.

GS-0976 (Firsocostat): an investigational liver-directed acetyl-CoA carboxylase (ACC) inhibitor for the treatment of non-alcoholic steatohepatitis (NASH)

Introduction: De novo lipogenesis (DNL) plays a major role in fatty acid metabolism and contributes significantly to triglyceride accumulation within the hepatocytes in patients with nonalcoholic steatohepatitis (NASH). Acetyl-CoA carboxylase (ACC) converts acetyl-CoA to malonyl CoA and is a rate-controlling step in DNL. Furthermore, malonyl-CoA is an important regulator of hepatic mitochondrial fat oxidation through its ability to inhibit carnitine palmitoyltransferase I. Therefore, inhibiting ACC pharmacologically represents an attractive approach to treating NASH.Areas covered: This article summarizes preclinical and clinical data on the efficacy and safety of the liver-targeted ACC inhibitor GS-0976 (Firsocostat) for the treatment of NASH. In a phase 2 trial that included 126 patients with NASH and fibrosis, GS-0976 20 mg daily for 12 weeks showed significant relative reduction in liver fat by 29%; however, treatment was associated with an increase in plasma triglycerides with 16 patients having levels >500 mg/dL.Expert opinion: Preclinical and preliminary clinical data support the development of GS-0976 as treatment for NASH. ACC-induced hypertriglyceridemia can be mitigated by fish oil or fibrates, but the long-term cardiovascular effects require further investigations.

Acetyl-CoA carboxylase (ACC) as a therapeutic target for metabolic syndrome and recent developments in ACC1/2 inhibitors

Introduction: Acetyl-CoA Carboxylase (ACC) is an essential rate-limiting enzyme in fatty acid metabolism. For many years, ACC inhibitors have gained great attention for developing therapeutics for various human diseases including microbial infections, metabolic syndrome, obesity, diabetes, and cancer. Areas covered: We present a comprehensive review and update of ACC inhibitors. We look at the current advance of ACC inhibitors in clinical studies and the implications in drug discovery. We searched ScienceDirect ( https://www.sciencedirect.com/ ), ACS ( https://pubs.acs.org/ ), Wiley ( https://onlinelibrary.wiley.com/ ), NCBI ( https://www.ncbi.nlm.nih.gov/ ) and World Health Organization ( https://www.who.int/ ). The keywords used were Acetyl-CoA Carboxylase, lipid, inhibitors and metabolic syndrome. All documents were published before June 2019. Expert opinion: The key regulatory role of ACC in fatty acid synthesis and oxidation pathways makes it an attractive target for various metabolic diseases. In particular, the combination of ACC inhibitors with other drugs is a new strategy for the treatment of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Expanding the clinical indications for ACC inhibitors will be one of the hot directions in the future. It is also worth looking forward to exploring safe and efficient inhibitors that act on the BC domain of ACC.

Liraglutide improves insulin sensitivity in high fat diet induced diabetic mice through multiple pathways

Glucagon like peptide-1 (GLP-1) promotes postprandial insulin secretion. Liraglutide, a full agonist of the GLP-1 receptor, reduces body weight, improve insulin sensitivity, and alleviate Non Alcoholic Fatty Liver Disease (NAFLD). However, the underlying mechanisms remain unclear. This study aims to explore the underlying mechanisms and cell signaling pathways involved in the anti-obesity and anti-inflammatory effects of liraglutide. Mice were fed a high fat high sucrose diet to induce diabetes, diabetic mice were divided into two groups and injected with liraglutide or vehicle for 14 days. Liraglutide treatment improved insulin sensitivity, accompanied with reduced expression of the phosphorylated Acetyl-CoA carboxylase-2 (ACC2) and upregulation of long chain acyl CoA dehydrogenase (LCAD) in insulin sensitive tissues. Furthermore, liraglutide induced adenosine monophosphate-activated protein kinase-α (AMPK-α) and Sirtuin-1(Sirt-1) protein expression in liver and perigonadal fat. Liraglutide induced elevation of fatty acid oxidation in these tissues may be mediated through the AMPK-Sirt-1 cell signaling pathway. In addition, liraglutide induced brown adipocyte differentiation in skeletal muscle, including induction of uncoupling protein-1 (UCP-1) and PR-domain-containing-16 (PRDM-16) protein in association with induction of SIRT-1. Importantly, liraglutide displayed anti-inflammation effect. Specifically, liraglutide led to a significant reduction in circulating interleukin-1 β (IL-1 β) and interleukin-6 (IL-6) as well as hepatic IL-1 β and IL-6 content. The expression of inducible nitric oxide synthase (iNOS-1) and cyclooxygenase-2 (COX-2) in insulin sensitive tissues was also reduced following liraglutide treatment. In conclusion, liraglutide improves insulin sensitivity through multiple pathways resulting in reduction of inflammation, elevation of fatty acid oxidation, and induction of adaptive thermogenesis.

Extract and fraction of Cassia occidentalis L. (a synonym of Senna occidentalis) have osteogenic effect and prevent glucocorticoid-induced osteopenia

ETHNOPHARMACOLOGICAL RELEVANCE

Cassia occidentalis L., a synonym of Senna occidentalis (belongs to Caesalpiniaceae family) is an annual plant. Pursuing a lead from a folk practice prevalent since the late nineteenth century in Andhra Pradesh, a Southern state of India, of use of Cassia occidentalis leaf and stem for treating patients with fracture and bone diseases, we have not only confirmed its fracture healing activity but also demonstrated efficacy in preventing glucocorticoid-induced osteoporosis (GIO), the commonest form of medication-induced bone loss caused chiefly due to impairment of bone formation.

AIM OF THE STUDY

In the present work, the effects of extract and fraction of leaf and stem of Cassia occidentalis was investigated in fracture healing and GIO models of rat. The study also aimed to identify osteogenic compounds from this plant.

MATERIALS AND METHODS

Ethanolic extracts from leaf and stem of Cassia occidentalis were prepared and their efficacy tested in rat femur osteotomy (fracture healing) model. Subsequently, a butanolic fraction was prepared and osteogenic efficacy compared with the ethanolic extract, and upon finding the former to be more potent, its osteogenic effect was studied in details in GIO model. Chemical finger-printing and isolation of ten pure compounds were done to assess their osteogenic effect in rat primary osteoblast cultures.

RESULTS

Ethanolic extract of stem was more effective than the leaf extract in enhancing bone regeneration at the site of osteotomy. Further, butanolic fraction of the ethanolic extract of stem was more effective than the later in bone regeneration at the femur osteotomy site and in preventing bone loss in GIO model. The mechanism of skeletal preservation involved stimulation of new bone formation and inhibition of bone resorption. As many as six osteogenic compounds were isolated out of which apigenin-6C-glucopyranoside was most effective in vitro.

CONCLUSION

Our study found that a standardized extract of an ethanolic extract and its butanolic fraction from the stem of Cassia occidentalis has osteogenic as well as anti-resorptive effects, resulting in the protection against glucocorticoid-induced bone loss. Our results contribute towards validation of the traditional use of Cassia occidentalis in fracture healing and also suggest its beneficial use in GIO for which clinical trials are warranted.

Changes in Intestinal Microbiota of Type 2 Diabetes in Mice in Response to Dietary Supplementation With Instant Tea or Matcha

OBJECTIVE

Gut microbiota plays a key role in metabolism and health in diabetes patients with gastrointestinal microbiota dysbiosis. Thus, regulating the ecological balance of gut microbiota may provide a pathway toward improvement for these patients. Our previous study showed that functional ingredients in tea may inhibit cornstarch digestion in vitro.

METHODS

A cornstarch-tea diet was developed, and in this study we investigated the effects of such a diet on blood glucose and gut microbiota in diabetic mice.

RESULTS

Diabetes resulted in significant weight loss, hyperphagia and hyperglycemia. 16S rDNA sequencing revealed that in diabetes there is significantly increased Bacteroidaceae, Helicobacteraceae, Ruminococcaceae, Enterobacteriaceae, Rikenellaceae and Saccharibacteria_genera_incertae_sedis, and significantly decreased Lactobacillaceae, Prevotellaceae, Coriobacteriaceae, Verrucomicrobiaceae and Bifidobacteriaceae. The cornstarch‒tea diet resulted in a trend toward reduced blood glucose, with particularly increased levels of Coriobacteriaceae, Lactobacillaceae, Prevotellaceae and Bifidobacteriaceae, and decreased Bacteroidaceae, Ruminococcaceae, Helicobacteraceae and Enterobacteriaceae.

CONCLUSIONS

Instant tea and matcha supplementation had beneficial effects on regulation of blood glucose and gut microbiota, reversing the changes in microbiota caused by alloxan injection. The cornstarch‒tea regulation pathway is involved in bacterium group regulation rather than single-species regulation, which suggests that cornstarch combined with tea may be used as a functional food supplement for diabetes patients.

Hierarchical activation of compartmentalized pools of AMPK depends on severity of nutrient or energy stress

AMPK, a master regulator of metabolic homeostasis, is activated by both AMP-dependent and AMP-independent mechanisms. The conditions under which these different mechanisms operate, and their biological implications are unclear. Here, we show that, depending on the degree of elevation of cellular AMP, distinct compartmentalized pools of AMPK are activated, phosphorylating different sets of targets. Low glucose activates AMPK exclusively through the AMP-independent, AXIN-based pathway in lysosomes to phosphorylate targets such as ACC1 and SREBP1c, exerting early anti-anabolic and pro-catabolic roles. Moderate increases in AMP expand this to activate cytosolic AMPK also in an AXIN-dependent manner. In contrast, high concentrations of AMP, arising from severe nutrient stress, activate all pools of AMPK independently of AXIN. Surprisingly, mitochondrion-localized AMPK is activated to phosphorylate ACC2 and mitochondrial fission factor (MFF) only during severe nutrient stress. Our findings reveal a spatiotemporal basis for hierarchical activation of different pools of AMPK during differing degrees of stress severity.

Fatty acid metabolism in CD8+ T cell memory: Challenging current concepts

CD8⁺ T cells are key members of the adaptive immune response against infections and cancer. As we discuss in this review, these cells can present diverse metabolic requirements, which have been intensely studied during the past few years. Our current understanding suggests that aerobic glycolysis is a hallmark of activated CD8⁺ T cells, while naive and memory (T_mem ) cells often rely on oxidative phosphorylation, and thus mitochondrial metabolism is a crucial determinant of CD8⁺ T_mem cell development. Moreover, it has been proposed that CD8⁺ T_mem cells have a specific requirement for the oxidation of long-chain fatty acids (LC-FAO), a process modulated in lymphocytes by the enzyme CPT1A. However, this notion relies heavily on the metabolic analysis of in vitro cultures and on chemical inhibition of CPT1A. Therefore, we introduce more recent studies using genetic models to demonstrate that CPT1A-mediated LC-FAO is dispensable for the development of CD8⁺ T cell memory and protective immunity, and question the use of chemical inhibitors to target this enzyme. We discuss insights obtained from those and other studies analyzing the metabolic characteristics of CD8⁺ T_mem cells, and emphasize how T cells exhibit flexibility in their choice of metabolic fuel.

Thermal challenge alters the transcriptional profile of the breast muscle in turkey poults

Extremes in temperature represent environmental stressors that impact the well-being and economic value of poultry. As homeotherms, young poultry with immature thermoregulatory systems are especially susceptible to thermal extremes. Genetic variation and differences in gene expression resulting from selection for production traits, likely contribute to thermal stress response. This study was designed to investigate in vivo transcriptional changes in the breast muscle of young turkey poults from an unselected randombred line and one selected for 16 wk body weight under hot and cold thermal challenge. Newly hatched turkey poults were brooded for 3 d at one of 3 temperatures: control (35°C), cold (31°C), or hot (39°C). Samples of the pectoralis major were harvested and subjected to deep RNA sequencing. Significant differential gene expression was observed in both growth-selected and randombred birds at both temperature extremes when compared to control-brooded poults. Growth-selected birds responded to thermal stress through changes in genes predicted to have downstream transcriptional effects and that would result in reduced muscle growth. Slower growing randombred birds responded to thermal stress through modulation of lipid-related genes, suggesting reduction in lipid storage, transport, and synthesis, consistent with changes in energy metabolism required to maintain body temperature.

GS-0976 Reduces Hepatic Steatosis and Fibrosis Markers in Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

De novo lipogenesis is increased in livers of patients with nonalcoholic steatohepatitis (NASH). Acetyl-coenzyme carboxylase catalyzes the rate-limiting step in this process. We evaluated the safety and efficacy of GS-0976, an inhibitor of acetyl-coenzyme A carboxylase in liver, in a phase 2 randomized placebo-controlled trial of patients with NASH.

METHODS

We analyzed data from 126 patients with hepatic steatosis of at least 8%, based on the magnetic resonance imaging-estimated proton density fat fraction (MRI-PDFF), and liver stiffness of at least 2.5 kPa, based on magnetic resonance elastography measurement or historical biopsy result consistent with NASH and F1-F3 fibrosis. Patients were randomly assigned (2:2:1) to groups given GS-0976 20 mg, GS-0976 5 mg, or placebo daily for 12 weeks, from August 8, 2016 through July 18, 2017. Measures of hepatic steatosis, stiffness, serum markers of fibrosis, and plasma metabolomics were evaluated. The primary aims were to confirm previous findings and evaluate the relation between dose and efficacy.

RESULTS

A relative decrease of at least 30% from baseline in MRI-PDFF (PDFF response) occurred in 48% of patients given GS-0976 20 mg (P = .004 vs placebo), 23% given GS-0976 5 mg (P = .43 vs placebo), and 15% given placebo. Median relative decreases in MRI-PDFF were greater in patients given GS-0976 20 mg (decrease of 29%) than those given placebo (decrease of 8%; P = .002). Changes in magnetic resonance elastography-measured stiffness did not differ among groups, but a dose-dependent decrease in the fibrosis marker tissue inhibitor of metalloproteinase 1 was observed in patients given GS-0976 20 mg. Plasma levels of acylcarnitine species also decreased in patients with a PDFF response given GS-0976 20 mg. GS-0976 was safe, but median relative increases of 11% and 13% in serum levels of triglycerides were observed in patients given GS-0976.

CONCLUSIONS

In a randomized placebo-controlled trial of patients with NASH, we found 12-week administration of GS-0976 20 mg decreased hepatic steatosis, selected markers of fibrosis, and liver biochemistry. ClinicalTrials.gov ID NCT02856555.