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Lafora disease (LD) is a rare autosomal recessive disorder characterized by progressive myoclonic epilepsy followed by continuous neurological decline, culminating in death within 10 years. LD leads to accumulation of insoluble, abnormal, glycogen–like structures called Lafora bodies (LBs). It is caused by mutations in the gene encoding glycogen phosphatase (EPM2A) or the E3 ubiquitin ligase malin (EPM2B/NHLRC1). These two proteins are involved in an intricate, however, incompletely elucidated pathway governing glycogen metabolism. The formation of EPM2A and malin signaling complex promotes the ubiquitination of proteins participating in glycogen metabolism, where dysfunctional mutations lead to the formation of LBs. Herein, we describe a 13-years-old child with LD due to a NHLRC1 (c.386C > A, p.Pro129His) mutation, who has developed diabetes mellitus and was treated with metformin. We discuss how basic mechanisms of LD could be linked to β-cell dysfunction and insulin resistance.

Glycogen serves as a metabolic sink in cyanobacteria. Glycogen deficiency causes the extracellular release of distinctive metabolites such as pyruvate and 2-oxoglutarate upon nitrogen depletion; however, the mechanism has not been fully elucidated. This study aimed to elucidate the mechanism of carbon partitioning in glycogen-deficient cyanobacteria. Extracellular and intracellular metabolites in a glycogen-deficient ΔglgC mutant of Synechococcus elongatus PCC 7942 were comprehensively analyzed. In the presence of a nitrogen source, the ΔglgC mutant released extracellular glutamate rather than pyruvate and 2-oxoglutarate, whereas its intracellular glutamate level was lower than that in the wild-type strain. The de novo synthesis of glutamate increased in the ΔglgC mutant, suggesting that glycogen deficiency enhanced carbon partitioning into glutamate and extracellular excretion through an unidentified transport system. This study proposes a model in which glutamate serves as the prime extracellular metabolic sink alternative to glycogen when nitrogen is available., (© 2024. The Author(s).)

Reprogramming of cellular metabolism is a driving factor of tumour progression and radiation therapy resistance. Identifying biochemical signatures associated with tumour radioresistance may assist with the development of targeted treatment strategies to improve clinical outcomes. Raman spectroscopy (RS) can monitor post-irradiation biomolecular changes and signatures of radiation response in tumour cells in a label-free manner. Convolutional Neural Networks (CNN) perform feature extraction directly from data in an end-to-end learning manner, with high classification performance. Furthermore, recently developed CNN explainability techniques help visualize the critical discriminative features captured by the model. In this work, a CNN is developed to characterize tumour response to radiotherapy based on its degree of radioresistance. The model was trained to classify Raman spectra of three human tumour cell lines as radiosensitive (LNCaP) or radioresistant (MCF7, H460) over a range of treatment doses and data collection time points. Additionally, a method based on Gradient-Weighted Class Activation Mapping (Grad-CAM) was used to determine response-specific salient Raman peaks influencing the CNN predictions. The CNN effectively classified the cell spectra, with accuracy, sensitivity, specificity, and F1 score exceeding 99.8%. Grad-CAM heatmaps of H460 and MCF7 cell spectra (radioresistant) exhibited high contributions from Raman bands tentatively assigned to glycogen, amino acids, and nucleic acids. Conversely, heatmaps of LNCaP cells (radiosensitive) revealed activations at lipid and phospholipid bands. Finally, Grad-CAM variable importance scores were derived for glycogen, asparagine, and phosphatidylcholine, and we show that their trends over cell line, dose, and acquisition time agreed with previously established models. Thus, the CNN can accurately detect biomolecular differences in the Raman spectra of tumour cells of varying radiosensitivity without requiring manual feature extraction. Finally, Grad-CAM may help identify metabolic signatures associated with the observed categories, offering the potential for automated clinical tumour radiation response characterization.

This study compared differences in exercise capacity as well as muscle glycogen content and degradation, and mitochondrial enzyme activity between C57BL/6J and BALB/cA mice. In exercise tests, grip strength was higher in BALB/cA mice. In Rotarod and Inverted screen test, C57BL/6J mice had significantly longer exercise durations and showed differences in motor function and muscle endurance time. Glycogen in the liver and muscle of C57BL/6J mice was significantly decreased after 20 min of swimming. Muscle glycogen content in BALB/cA mice was higher than in C57BL/6J, but swimming induced no decrease in glycogen content. Glycogen phosphorylase in muscle was inactive in the absence of AMP, and its activity increased in a concentration-dependent manner with the addition of AMP in C57BL/6J mice. In BALB/cA mice, phosphorylase activity was increased by AMP, but not further increased by higher concentrations of AMP. The citrate synthase activity in muscle did not differ between C57BL/6J and BALB/cA mice. The results of this study suggested that the reactivity of muscle glycogen phosphorylase to AMP differs among strains of mice and affects glycogen availability during exercise.

Glycogen metabolism plays a key role in the development of hepatocellular carcinoma (HCC), but the function of glycogen metabolism genes in the tumor microenvironment (TME) is still to be elucidated. Single-cell RNA-seq data were obtained from ten HCC tumor samples totaling 64,545 cells, and 65 glycogen metabolism genes were analyzed by a nonnegative matrix factorization (NMF). The prognosis and immune response of new glycogen TME cell clusters were predicted by using HCC and immunotherapy cohorts from public databases. HCC single-cell analysis was divided into fibroblasts, NT T cells, macrophages, endothelial cells, and B cells, which were separately divided into new cell clusters by glycogen metabolism gene annotation. Pseudo-temporal trajectory analysis demonstrated the temporal differentiation trajectory of different glycogen subtype cell clusters. Cellular communication analysis revealed extensive interactions between endothelial cells with glycogen metabolizing TME cell-related subtypes and different glycogen subtype cell clusters. SCENIC analysis of transcription factors upstream of TME cell clusters with different glycogen metabolism. In addition, TME cell clusters of glycogen metabolism were found to be enriched in expression in CAF subtypes, CD8 depleted, M1, and M2 types. Bulk-seq analysis showed the prognostic significance of glycogen metabolism-mediated TME cell clusters in HCC, while a significant immune response was found in the immunotherapy cohort in patients treated with immune checkpoint blockade (ICB), especially for CAFs, T cells, and macrophages. In summary, our study reveals for the first time that glycogen metabolism mediates intercellular communication in the hepatocellular carcinoma microenvironment while elucidating the anti-tumor mechanisms and immune prognostic responses of different subtypes of cell clusters., Competing Interests: This research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Zhang et al.)

This study was conducted to investigate the energy mobilisation preference and ionoregulation pattern of female tilapia, Oreochromis sp. living in different environments. Three different treatments of tilapia as physiology compromising model were compared; tilapia cultured in recirculating aquaculture system (RAS as Treatment I-RAS), tilapia cultured in open water cage (Treatment II-Cage) and tilapia transferred from cage and cultured in RAS (Treatment III-Compensation). Results revealed that tilapia from Treatment I and III mobilised lipid to support gonadogenesis, whilst Treatment II tilapia mobilised glycogen as primary energy for daily exercise activity and reserved protein for growth. The gills and kidney Na + /K + ATPase (NKA) activities remained relatively stable to maintain homeostasis with a stable Na + and K + levels. As a remark, this study revealed that tilapia strategized their energy mobilisation preference in accessing glycogen as an easy energy to support exercise metabolism and protein somatogenesis in cage culture condition, while tilapia cultured in RAS mobilised lipid for gonadagenesis purposes., (© 2024. The Author(s).)

Lafora disease is a rare and fatal form of progressive myoclonic epilepsy with onset during early adolescence. The disease is caused by mutations in EPM2A, encoding laforin, or EPM2B, encoding malin. Both proteins have functions that affect glycogen metabolism, including glycogen dephosphorylation by laforin and ubiquitination of enzymes involved in glycogen metabolism by malin. Lack of function of laforin or malin results in the accumulation of polyglucosan that forms Lafora bodies in the central nervous system and other tissues. Enzyme replacement therapy through intravenous administration of alglucosidase alfa (Myozyme®) has shown beneficial effects removing polyglucosan aggregates in Pompe disease. We evaluated the effectiveness of intracerebroventricular administration of alglucosidase alfa in the Epm2a -/- knock-out and Epm2a R240X knock-in mouse models of Lafora disease. Seven days after a single intracerebroventricular injection of alglucosidase alfa in 12-month-old Epm2a -/- and Epm2a R240X mice, the number of Lafora bodies was not reduced. Additionally, a prolonged infusion of alglucosidase alfa for 2 or 4 weeks in 6- and 9-month-old Epm2a -/- mice did not result in a reduction in the number of LBs or the amount of glycogen in the brain. These findings hold particular significance in guiding a rational approach to the utilization of novel therapies in Lafora disease., (Copyright © 2024 Elsevier B.V. All rights reserved.)

During submaximal exercise, there is a heterogeneous recruitment of skeletal muscle fibers, with an ensuing heterogeneous depletion of muscle glycogen both within and between fiber types. Here, we show that the mean (95% CI) mitochondrial volume as a percentage of fiber volume of non-glycogen-depleted fibers was 2 (-10:6), 5 (-21:11), and 12 (-21:-2)% lower than all the sampled fibers after continuing exercise for 1, 2 h, and until task failure, respectively. Therefore, a glycogen-dependent fatigue of individual fibers during submaximal exercise may reduce the muscular oxidative power. These findings suggest a relationship between glycogen and mitochondrial content in individual muscle fibers, which is important for understanding fatigue during prolonged exercise., (© 2024 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Background and Aims: Alcohol consumption is a well-established risk factor for the onset and progression of hepatic steatosis. Perilipin 5 (Plin5), a lipid droplet protein, is an important protective factor against hepatic lipotoxicity induced by excessive lipolysis, but its role and molecular mechanism in alcoholic liver disease (ALD) are not fully elucidated., Methods: The optimized National Institute on Alcohol Abuse and Alcoholism model was used to construct ALD model mice. Automatic biochemical analyser was used for Biochemical Parameters. The primary hepatocytes and Plin5-overexpressed HepG2 cells (including full-length Plin5 and Plin5 deleting 444-464 aa) were used for in vitro experiment. Haematoxylin and Eosin staining, Oil Red O staining, Bodipy 493/503 staining, Periodic Acid-Schiff staining, immunohistochemistry and JC-1 staining were used to evaluate cell morphology, lipids, glycogen, inflammation and membrane potential. Commercially kits are used to detect glycolipid metabolites, such as triglycerides, glycogen, glucose, reactive oxygen species, lactic acids, ketone bodies. Fluorescently labelled deoxyglucose, NBDG, was used for glucose intake. An XF96 extracellular flux analyser was used to determinate oxygen consumption rate in hepatocytes. The morphological and structural damage of mitochondria was evaluated by electron microscopy. Classical ultracentrifugation is used to separate the subcellular organelles of tissues and cells. Immunoblotting and qPCR were used to detect changes in mRNA and protein levels of related genes., Results: Our results showed that the expression of Plin5 in mouse livers was enhanced by alcohol intake, and Plin5 deficiency aggravated the alcohol-induced liver injury. To clarify the mechanism, we found that Plin5 deficiency significantly elevated the hepatic NADH levels and ketone body production in the alcohol-treated mice. As NADH elevation could promote the reduction of pyruvate into lactate and then inhibit the gluconeogenesis, alcohol-treated Plin5-deficient mice exhibited more lactate production and severer hypoglycemia. These results implied that Plin5 deficiency impaired the mitochondrial oxidative functions in the presence of alcohol. In addition, we demonstrated that Plin5 could be recruited onto mitochondria by alcohol, while Plin5 without mitochondrial targeting sequences lost its mitochondrial protection functions., Conclusion: Collectively, this study demonstrated that the mitochondrial Plin5 could protect the alcohol-induced mitochondrial injury, which provides an important new insight on the roles of Plin5 in highly oxidative tissues., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

d-Tetramethrin is one of the main components of mosquito control products, and is widely used for the control of dengue fever and insecticide production. Due to its widespread use, d-tetramethrin is a ubiquitous environmental pollutant and poses potential risks to human health. However, the effects of d-tetramethrin on liver morphology and function are not clearly established. In this study, we used zebrafish as an animal model to analyze the acute and chronic effects of d-tetramethrin exposure on the liver. We exposed zebrafish larvae and adults to different concentrations of d-tetramethrin and examined the impact of d-tetramethrin on lipid and glycogen metabolism, cellular properties, oxidative stress, cell proliferation, and apoptosis in the liver. We also analyzed transcriptional changes in genes related to apoptosis, inflammation, and cell proliferation using qPCR. Zebrafish exposed to d-tetramethrin exhibited severe liver damage, as evidenced by the presence of vacuoles and nuclear distortion in liver cells. The liver area in zebrafish larvae of the treatment group was significantly smaller than that of the control group. Significant lipid accumulation and decreased glycogen levels were observed in the livers of both zebrafish larvae and adults exposed to d-tetramethrin. Furthermore, d-tetramethrin exposure induced apoptosis and inflammation in zebrafish embryos. Additionally, d-tetramethrin caused liver damage, metabolic dysfunction, and impaired liver function. These results suggest that d-tetramethrin induces liver toxicity in zebrafish, by inducing oxidative stress and inhibiting cell proliferation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

Among the effects of the larval development of digenetic trematodes on their intermediate hosts, changes in the carbohydrate metabolism in the snails stand out. The aim of this study was to analyze, every 10 days after infection (d.p.i.), the effects of Paratanaisia bragai infection on the glycogen content in the digestive gland and cephalopedal mass in Subulina octona snail, and also verify the glucose concentration and the enzyme D - and L -lactate dehydrogenase activity (EC1.1.1.27 and EC1.1.1.28) (LDH) and the concentration of some metabolites(oxalic, succinic, pyruvic and lactic acid) presents in the hemolymph. Histochemical analisys were also performed. We verified a total increase of 54.81% in glucose concentration in infected snails and an oscillating pattern in the glycogen content in the cephalopedal mass and in the digestive gland. LDH activity shows an increase of 10 d.p.i. (+ 74.32%) and 40 d.p.i. (+ 47.81%) and decrease at 20 d.p.i. and 30 d.p.i. The concentrations of oxalic, succinic and pyruvic acids showed significant and progressive reductions; however, lactic acid had a significant increase. Histological and histochemical analysis showed a tissue disorganization in the cephalopedal mass of infected snails and morphological changes in the digestive gland. These results confirm that infection causes metabolic pathway changes in the snails due to activation of an alternative anaerobic pathway for producing energy, indicated by the increased lactic acid content and LDH activity., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Some acute exercise effects are influenced by postexercise (PEX) diet, and these diet-effects are attributed to differential glycogen resynthesis. However, this idea is challenging to test rigorously. Therefore, we devised a novel genetic model to modify muscle glycogen synthase 1 (GS1) expression in rat skeletal muscle with an adeno-associated virus (AAV) short hairpin RNA knockdown vector targeting GS1 (shRNA-GS1). Contralateral muscles were injected with scrambled shRNA (shRNA-Scr). Muscles from exercised (2-hour-swim) and time-matched sedentary (Sed) rats were collected immediately postexercise (IPEX), 5-hours-PEX (5hPEX), or 9-hours-PEX (9hPEX). Rats in 5hPEX and 9hPEX experiments were refed (RF) or not-refed (NRF) chow. Muscles were analyzed for glycogen, abundance of metabolic proteins (pyruvate dehydrogenase kinase 4, PDK4; peroxisome proliferator-activated receptor γ coactivator-1α, PGC1α; hexokinase II, HKII; glucose transporter 4, GLUT4), AMP-activated protein kinase phosphorylation (pAMPK), and glycogen metabolism-related enzymes (glycogen phosphorylase, PYGM; glycogen debranching enzyme, AGL; glycogen branching enzyme, GBE1). shRNA-GS1 versus paired shRNA-Scr muscles had markedly lower GS1 abundance. IPEX versus Sed rats had lower glycogen and greater pAMPK, and neither of these IPEX-values differed for shRNA-GS1 versus paired shRNA-Scr muscles. IPEX versus Sed groups did not differ for abundance of metabolic proteins, regardless of GS1 knockdown. Glycogen in RF-rats was lower for shRNA-GS1 versus paired shRNA-Scr muscles at both 5hPEX and 9hPEX. HKII protein abundance was greater for 5hPEX versus Sed groups, regardless of GS1 knockdown or diet, and despite differing glycogen levels. At 9hPEX, shRNA-GS1 versus paired shRNA-Scr muscles had greater PDK4 and PGC1α abundance within each diet group. However, the magnitude of PDK4 or PGC1α changes was similar in each diet group regardless of GS1 knockdown although glycogen differed between paired muscles only in RF-rats. In summary, we established a novel genetic approach to investigate the relationship between muscle glycogen and other exercise effects. Our results suggest that exercise-effects on abundance of several metabolic proteins did not uniformly correspond to differences in postexercise glycogen., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Kwak et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

In response to a meal, insulin drives hepatic glycogen synthesis to help regulate systemic glucose homeostasis. The mechanistic target of rapamycin complex 1 (mTORC1) is a well-established insulin target and contributes to the postprandial control of liver lipid metabolism, autophagy, and protein synthesis. However, its role in hepatic glucose metabolism is less understood. Here, we used metabolomics, isotope tracing, and mouse genetics to define a role for liver mTORC1 signaling in the control of postprandial glycolytic intermediates and glycogen deposition. We show that mTORC1 is required for glycogen synthase activity and glycogenesis. Mechanistically, hepatic mTORC1 activity promotes the feeding-dependent induction of Ppp1r3b, a gene encoding a phosphatase important for glycogen synthase activity whose polymorphisms are linked to human diabetes. Reexpression of Ppp1r3b in livers lacking mTORC1 signaling enhances glycogen synthase activity and restores postprandial glycogen content. mTORC1-dependent transcriptional control of Ppp1r3b is facilitated by FOXO1, a well characterized transcriptional regulator involved in the hepatic response to nutrient intake. Collectively, we identify a role for mTORC1 signaling in the transcriptional regulation of Ppp1r3b and the subsequent induction of postprandial hepatic glycogen synthesis.

Background: Water-free transportation (WFT), as a novel strategy for express delivery of live shrimp (Litopenaeus vannamei), was developed recently. However, air exposure during this transportation arouses a series of abiotic stress to the shrimp. In the present study, the influences of WFT stress on glycolysis and lipolysis metabolism and meat quality (umami flavor and drip loss) were investigated in comparison with conventional water transportation (WT)., Results: The results showed that type II muscle fibers with the feature of anaerobic metabolism were dominated in shrimp flesh. In addition, the increments of intracellular Ca 2+ was detected in WFT and WT, which then activated the AMP-activated protein kinase pathway and promoted the consumption of glycogen, as well as the accumulation of lactate and lipolysis, under the enzymolysis of hexokinase, pyruvate kinase, lactate dehydrogenase and adipose triglyceride lipase. Glycogen glycolyzed to latate. Meanwhile, ATP degraded along with glycolysis resulting in the generation of ATP-related adenosine phosphates such as inosine monophosphate with umami flavor and phosphoric acid. More remarkable (P < 0.05) physiological changes (except lactate dehydrogenase and lactate) were observed in WFT compared to WT. Additionally, the fatty acid profile also slightly changed., Conclusion: The transport stress induced significant energy metabolism changes of shrimp flesh and therefore effected the flesh quality. The intensifications of freshness (K-value) of shrimp flesh were detected as a result of ATP degradation, which were more pronounced after WFT. However, the drip loss of shrimp flesh was more significantly increased (P < 0.05) after WFT compared to WT. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

There is a growing interest in studies involving carbohydrate (CHO) manipulation and subsequent adaptations to endurance training. This study aimed to analyze whether a periodized carbohydrate feeding strategy based on a daily training session has any advantages compared to a high-carbohydrate diet in well-trained cyclists. Seventeen trained cyclists ( V O 2peak = 70.8 ± 6.5 mL·kg -1 ·min -1 ) were divided into two groups, a periodized (PCHO) group and a high-carbohydrate (HCHO) group. Both groups performed the same training sessions for five weeks. In the PCHO group, 13 training sessions were performed with low carbohydrate availability. In the HCHO group, all sessions were completed following previous carbohydrate intake to ensure high pre-exercise glycogen levels. In both groups, there was an increase in the maximal lactate steady state (MLSS) (PCHO: 244.1 ± 29.9 W to 253.2 ± 28.4 W; p = 0.008; HCHO: 235.8 ± 21.4 W to 246.9 ± 16.7 W; p = 0.012) but not in the time to exhaustion at MLSS intensity. Both groups increased the percentage of muscle mass (PCHO: p = 0.021; HCHO: p = 0.042) and decreased the percent body fat (PCHO: p = 0.021; HCHO: p = 0.012). We found no differences in carbohydrate or lipid oxidation, heart rate, and post-exercise lactate concentration. Periodizing the CHO intake in well-trained cyclists during a 5-week intervention did not elicit superior results to an energy intake-matched high-carbohydrate diet in any of the measured outcomes.

Glycogen synthase 1 (GYS1), the rate-limiting enzyme in muscle glycogen synthesis, plays a central role in energy homeostasis and has been proposed as a therapeutic target in multiple glycogen storage diseases. Despite decades of investigation, there are no known potent, selective small-molecule inhibitors of this enzyme. Here, we report the preclinical characterization of MZ-101, a small molecule that potently inhibits GYS1 in vitro and in vivo without inhibiting GYS2, a related isoform essential for synthesizing liver glycogen. Chronic treatment with MZ-101 depleted muscle glycogen and was well tolerated in mice. Pompe disease, a glycogen storage disease caused by mutations in acid α glucosidase (GAA), results in pathological accumulation of glycogen and consequent autophagolysosomal abnormalities, metabolic dysregulation, and muscle atrophy. Enzyme replacement therapy (ERT) with recombinant GAA is the only approved treatment for Pompe disease, but it requires frequent infusions, and efficacy is limited by suboptimal skeletal muscle distribution. In a mouse model of Pompe disease, chronic oral administration of MZ-101 alone reduced glycogen buildup in skeletal muscle with comparable efficacy to ERT. In addition, treatment with MZ-101 in combination with ERT had an additive effect and could normalize muscle glycogen concentrations. Biochemical, metabolomic, and transcriptomic analyses of muscle tissue demonstrated that lowering of glycogen concentrations with MZ-101, alone or in combination with ERT, corrected the cellular pathology in this mouse model. These data suggest that substrate reduction therapy with GYS1 inhibition may be a promising therapeutic approach for Pompe disease and other glycogen storage diseases.

Insulin sensitivity and metabolic flexibility decrease in response to bed rest, but the temporal and causal adaptations in human skeletal muscle metabolism are not fully defined. Here, we use an integrative approach to assess human skeletal muscle metabolism during bed rest and provide a multi-system analysis of how skeletal muscle and the circulatory system adapt to short- and long-term bed rest (German Clinical Trials: DRKS00015677). We uncover that intracellular glycogen accumulation after short-term bed rest accompanies a rapid reduction in systemic insulin sensitivity and less GLUT4 localization at the muscle cell membrane, preventing further intracellular glycogen deposition after long-term bed rest. We provide evidence of a temporal link between the accumulation of intracellular triglycerides, lipotoxic ceramides, and sphingomyelins and an altered skeletal muscle mitochondrial structure and function after long-term bed rest. An intracellular nutrient overload therefore represents a crucial determinant for rapid skeletal muscle insulin insensitivity and mitochondrial alterations after prolonged bed rest., Competing Interests: Declaration of interests The authors declare no competing interest., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Glycogen storage disease type III (GSDIII) is a rare inborn error of metabolism affecting liver, skeletal muscle, and heart due to mutations of the AGL gene encoding for the glycogen debranching enzyme (GDE). No curative treatment exists for GSDIII. The 4.6 kb GDE cDNA represents the major technical challenge toward the development of a single recombinant adeno-associated virus-derived (rAAV-derived) vector gene therapy strategy. Using information on GDE structure and molecular modeling, we generated multiple truncated GDEs. Among them, an N-terminal-truncated mutant, ΔNter2-GDE, had a similar efficacy in vivo compared with the full-size enzyme. A rAAV vector expressing ΔNter2-GDE allowed significant glycogen reduction in heart and muscle of Agl-/- mice 3 months after i.v. injection, as well as normalization of histology features and restoration of muscle strength. Similarly, glycogen accumulation and histological features were corrected in a recently generated Agl-/- rat model. Finally, transduction with rAAV vectors encoding ΔNter2-GDE corrected glycogen accumulation in an in vitro human skeletal muscle cellular model of GSDIII. In conclusion, our results demonstrated the ability of a single rAAV vector expressing a functional mini-GDE transgene to correct the muscle and heart phenotype in multiple models of GSDIII, supporting its clinical translation to patients with GSDIII.

Pompe disease is a lysosomal storage disorder caused by deficiency of acid alpha-glucosidase (GAA), resulting in glycogen accumulation with profound pathology in skeletal muscle. We recently developed an optimized form of lentiviral gene therapy for Pompe disease in which a codon-optimized version of the GAA transgene (LV-GAAco) was fused to an insulin-like growth factor 2 (IGF2) peptide (LV-IGF2.GAAco), to promote cellular uptake via the cation-independent mannose-6-phosphate/IGF2 receptor. Lentiviral gene therapy with LV-IGF2.GAAco showed superior efficacy in heart, skeletal muscle, and brain of Gaa -/- mice compared to gene therapy with untagged LV-GAAco. Here, we used quantitative mass spectrometry using TMT labeling to analyze the muscle proteome and the response to gene therapy in Gaa -/- mice. We found that muscle of Gaa -/- mice displayed altered levels of proteins including those with functions in the CLEAR signaling pathway, autophagy, cytoplasmic glycogen metabolism, calcium homeostasis, redox signaling, mitochondrial function, fatty acid transport, muscle contraction, cytoskeletal organization, phagosome maturation, and inflammation. Gene therapy with LV-GAAco resulted in partial correction of the muscle proteome, while gene therapy with LV-IGF2.GAAco resulted in a near-complete restoration to wild type levels without inducing extra proteomic changes, supporting clinical development of lentiviral gene therapy for Pompe disease. SIGNIFICANCE: Lysosomal glycogen accumulation is the primary cause of Pompe disease, and leads to a cascade of pathological events in cardiac and skeletal muscle and in the central nervous system. In this study, we identified the proteomic changes that are caused by Pompe disease in skeletal muscle of a mouse model. We showed that lentiviral gene therapy with LV-IGF2.GAAco nearly completely corrects disease-associated proteomic changes. This study supports the future clinical development of lentiviral gene therapy with LV-IGF2.GAAco as a new treatment option for Pompe disease., Competing Interests: Declaration of Competing Interest A.T. van der Ploeg received funding for research, clinical trials and as advisor from Sanofi-Genzyme, Amicus Therapeutics, Biomarin, Ultragenix, Sarepta, Audentes and Spark Therapeutics on enzyme replacement therapy or next-generation therapies in the field of Pompe disease, and other lysosomal storage diseases or neuromuscular disorders, under agreements with Erasmus MC University Medical Center. N. van Til has been employee of and advisor to Avrobio. W.W.M. Pim Pijnappel and A.T. van der Ploeg are advisors of LentiCure B.V. W.W.M.Pijnappel, E. Vlaar, and A.T. van der Ploeg are inventors on patents in the field of gene therapy., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Atrazine (ATZ) is a widely used herbicide that has toxic effects on animals. Melatonin (MLT) is a natural hormone with strong antioxidant properties. However, the effect of MLT on the glucose metabolism disorder caused by ATZ is still unclear. Mice were divided into four groups randomly and given 21 days of gavage: blank control group (Con), 5 mg/kg MLT group (MLT), 170 mg/kg ATZ group (ATZ), and 170 mg/kg ATZ and 5 mg/kg MLT group (ATZ + MLT). The results show that ATZ alters mRNA levels of metabolic enzymes related to glycogen synthesis and glycolysis and increased metabolites (glycogen, lactate, and pyruvate). ATZ causes abnormalities in glucose metabolism in mouse liver, interfering with glycemia regulation ability. MLT can regulate the endoplasmic reticulum to respond to disordered glucose metabolism in mice liver. This study suggested that MLT has the power to alleviate the ATZ-induced glycogen overdeposition and glycolytic deficit.

Ethnopharmacological Relevance: Globally, 537 million individuals are estimated to have diabetes. The traditional use of herbs for ameliorating diabetes symptoms is a common practice in Pakistan and use of Loranthus pulverulentus Wall (L. pulverulentus) by local people in Azad Jammu and Kashmir has been reported., Aim of the Study: In the present study, the antidiabetic potential of standardized n-butanol fraction of leaves of L. pulverulentus Wall, which is a parasite of Dalbergia sisso Roxb was assessed in both alloxan (ALX) and streptozotocin (STZ) diabetic animal models., Materials and Methods: Chemical characterization of BF was performed using HPLC, GCMS and UHPLC-MS. The effect of the fraction (250 mg/kg) on insulin, plasma free fatty acids, L-lactate, pyruvate, MDA, HbA1c and glycogen levels in ALX and STZ animal models was determined. Liver and renal profiles were analyzed in the STZ model. Toxicological studies were performed by hemolytic, Ames mutagenicity, DNA protection, and thrombolytic assays. Histopathological analysis of the pancreas, liver, and kidney was performed., Results: BF demonstrated highly significant (p < 0.001) antidiabetic potential in both diabetic models. BF significantly (p < 0.05) improved OGTT results in alloxanized diabetic mice and blocked the absorption of glucose from the gut. A significant (p < 0.001) increase in insulin levels and glycogen content in liver tissue and a decrease in plasma FFA, MDA, HbA1c, L-lactate, and pyruvate levels in STZ-diabetic mice were recorded. GC-MS and chromatographic analysis showed the presence of catechin, eugenol, longifolene, caryophyllene, Ar-tumerone and Geranyl-alpha-terpinene. Various metabolites with antidiabetic potential, including 4-hydroxycinnamyl alcohol 4-D-glucoside, zingerone glucoside, trans-trismethoxy resveratrol-d4, epigallocatechin 3-O-cinnamate, and β-glucogallin, were identified using UHPLC-MS. Animals treated with BF showed marked improvements in cellular structures of the pancreas, liver and kidneys. This fraction is non-mutagenic and protects the DNA., Conclusion: The experimental fraction contained potential antidiabetic bioactive compounds responsible for alleviating diabetes-associated biochemical dysregulation. The fraction increased insulin levels and enhanced glycogen storage in muscles and the liver. It blocked glucose absorption from the intestine and substantially decreased HbA1c, lactate, pyruvate, free fatty acids, lipid, liver and kidney damage. Therefore, the use of BF for the treatment of type-2 diabetes may be beneficial., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objective: Aim: The aim of the study was to investigate the activity of bioenergetic processes in rats under conditions of simultaneous exposure to malathion and carbon tetrachloride and after the use of enterosgel., Patients and Methods: Materials and Methods: Experiments were conducted on rats. The rats were divided into nine groups.Malathion was administered daily (for 30 days) at a dose of 20 mg / kg body weight of the animal. Tetrachloromethane was administered twice (every other day) as a 50% oil solution at a dose of 1.0 ml / kg body weight. The intensity of energy supply processes was assessed by the activity of succinate dehydrogenase and cytochrome oxidase, impaired carbohydrate metabolism in terms of glucose and glycogen., Results: Results: It was noted that succinate dehydrogenase activity in the liver decreased 2 times, in the myocardium - 1.6 times. On the thirty and seventh day of administration of toxicants after enterosorbent use, succinate dehydrogenase activity increased in the liver by 20%, cytochrome oxidase by 27%, in the myocardium - by 31% and 23%, respectively. The content of glucose in the serum after exposure to toxicants increased maximally (2.4 times) at the end of the study. In contrast, the glycogen content in the liver decreased by 48%, in the myocardium by 13%. The use of enterosgel resulted in a decrease in serum glucose., Conclusion: Conclusions: The use of enterosgel leads to the restoration of energy processes in the body of affected rats, which is confirmed by increased activity of mitochondrial enzymes, lowering glucose and increasing glycogen in the studied organs.

Introduction: The ventromedial hypothalamic nucleus (VMN) is an estrogen receptor (ER)-rich structure that regulates glucostasis. The role of nuclear but not membrane G protein-coupled ER-1 (GPER) in that function has been studied., Methods: Gene silencing and laser-catapult microdissection/immunoblot tools were used to examine whether GPER regulates transmitter and energy sensor function in dorsomedial (VMNdm) and/or ventrolateral (VMNvl) VMN counter-regulatory nitrergic and γ-Aminobutyric acid (GABA) neurons., Results: Intra-VMN GPER siRNA administration to euglycemic animals did not affect VMNdm or -vl nitrergic neuron nitric oxide synthase (nNOS), but upregulated (VMNdm) or lacked influence on (VMNvl) GABA nerve cell glutamate decarboxylase65/67 (GAD) protein. Insulin-induced hypoglycemia (IIH) caused GPER knockdown-reversible augmentation of nNOS, 5'-AMP-activated protein kinase (AMPK), and phospho-AMPK proteins in nitrergic neurons in both divisions. IIH had dissimilar effects on VMNvl (unchanged) versus VMNdm (increased) GABAergic neuron GAD levels, yet GPER knockdown affected these profiles. GPER siRNA prevented hypoglycemic upregulation of VMNvl and -dm GABA neuron AMPK without altering pAMPK expression., Conclusions: Outcomes infer that GPER exerts differential control of VMNdm versus -vl GABA transmission during glucostasis and is required for hypoglycemic upregulated nitrergic (VMNdm and -vl) and GABA (VMNdm) signaling. Glycogen metabolism is reported to regulate VMN nNOS and GAD proteins. Data show that GPER limits VMNvl glycogen phosphorylase (GP) protein expression and glycogen buildup during euglycemia but mediates hypoglycemic augmentation of VMNvl GP protein and glycogen content; VMNdm glycogen mass is refractory to GPER control. GPER regulation of VMNvl glycogen metabolism infers that this receptor may govern local counter-regulatory transmission in part by astrocyte metabolic coupling., (© 2023 S. Karger AG, Basel.)

This study was conducted to ascertain the effect of dietary Zn on growth and health status of juvenile largemouth bass (Micropterus salmoides). Six experimental diets with Zn level of 50.17, 56.74, 73.34, 86.03, 123.94, and 209.20 mg/kg, respectively were compounded using complex amino acid-chelated zinc, and were fed to juvenile fish (5.50 ± 0.10 g) for 70 d. The specific growth rate (SGR) varied with dietary Zn level in a quadratic model and peaked at the 73.34 mg/kg group, while the feeding rate exhibited an opposite trend (P < 0.05). The condition factor, hepatosomatic index and mesenteric fat index all exhibited a tendency similar with SGR (P < 0.05). Dietary Zn level affected serum total proteins, urea, triglycerides, and glucose (P < 0.05). Serum Zn and copper levels linearly increased with dietary Zn level, while serum iron and manganese showed the opposite trend. Serum superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) increased with dietary Zn level and reached a plateau at 86.03 mg/kg. Serum complement component 3 (C3), IgM, and lysozyme also were enhanced by 73.34 mg/kg Zn. Body protein content increased with zinc level up to 73.34 mg/kg, and then remained steadily. As dietary Zn level increased, hepatic lipid level increased and then reached a plateau at 86.03 mg/kg group, while glycogen increased linearly. Moreover, gene expression related to lipid and glycogen metabolism from liver transcriptome further explained the liver lipid and glycogen variations. To conclude, a dietary Zn requirement of 76.99 mg/kg was suggested for juvenile largemouth bass to improve growth, antioxidant capacity, and immune status., Competing Interests: Declaration of competing interest All listed authors declare no competing interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Glycogen storage disorders (GSDs) are inherited disorders of metabolism resulting from the deficiency of individual enzymes involved in the synthesis, transport, and degradation of glycogen. This literature review summarizes the development of gene therapy for the GSDs. The abnormal accumulation of glycogen and deficiency of glucose production in GSDs lead to unique symptoms based upon the enzyme step and tissues involved, such as liver and kidney involvement associated with severe hypoglycemia during fasting and the risk of long-term complications including hepatic adenoma/carcinoma and end stage kidney disease in GSD Ia from glucose-6-phosphatase deficiency, and cardiac/skeletal/smooth muscle involvement associated with myopathy +/- cardiomyopathy and the risk for cardiorespiratory failure in Pompe disease. These symptoms are present to a variable degree in animal models for the GSDs, which have been utilized to evaluate new therapies including gene therapy and genome editing. Gene therapy for Pompe disease and GSD Ia has progressed to Phase I and Phase III clinical trials, respectively, and are evaluating the safety and bioactivity of adeno-associated virus vectors. Clinical research to understand the natural history and progression of the GSDs provides invaluable outcome measures that serve as endpoints to evaluate benefits in clinical trials. While promising, gene therapy and genome editing face challenges with regard to clinical implementation, including immune responses and toxicities that have been revealed during clinical trials of gene therapy that are underway. Gene therapy for the glycogen storage diseases is under development, addressing an unmet need for specific, stable therapy for these conditions., (© 2023 SSIEM.)

The 5' adenosine monophosphate-activated protein kinase (AMPK) is an important skeletal muscle regulator implicated as a possible therapeutic target to ameliorate the local undesired deconditioning of disuse atrophy. However, the muscle-specific role of AMPK in regulating muscle function, fibrosis, and transcriptional reprogramming during physical disuse is unknown. The purpose of this study was to determine how the absence of both catalytic subunits of AMPK in skeletal muscle influences muscle force production, collagen deposition, and the transcriptional landscape. We generated skeletal muscle-specific tamoxifen-inducible AMPKα1/α2 knockout ( AMPKα -/- ) mice that underwent 14 days of hindlimb unloading (HU) or remained ambulatory for 14 days (AMB). We found that AMPKα -/- during ambulatory conditions altered body weight and myofiber size, decreased muscle function, depleted glycogen stores and TBC1 domain family member 1 (TBC1D1) phosphorylation, increased collagen deposition, and altered transcriptional pathways. Primarily, pathways related to cellular senescence and mitochondrial biogenesis and function were influenced by the absence of AMPKα. The effects of AMPKα -/- persisted, but were not worsened, following hindlimb unloading. Together, we report that AMPKα is necessary to maintain skeletal muscle quality. NEW & NOTEWORTHY We determined that skeletal muscle-specific AMPKα knockout (KO) mice display functional, fibrotic, and transcriptional alterations before and during muscle disuse atrophy. We also observed that AMPKα KO drives muscle fibrosis and pathways related to cellular senescence that continues during the hindlimb unloading period.

Sewage nutrient (e.g., nitrogen and phosphorus) biological removal performance is often limited by the deficient carbon source and undesirable glycogen accumulating organisms (GAOs), even in sulfate-containing wastewater. Thiosulfate (S 2 O 3 2- ) as a bioavailable, environmentally-benign, metastable and cost-effective agent has been regarded as electron carriers that induces high sulfur-mediated bacterial activity for nutrient removal from wastewater. In this study, the long-term effects of thiosulfate on the competition between sulfur-mediated bacteria (SMB, including sulfur-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB)) and GAOs were explored to further close the gap of our knowledge on the control of GAOs under carbon deficient wastewater. Three reactors were continuously operated for over 100 days and were fed with 200 mg acetate-COD/L and 20 (R1), 50 (R2) and 80 (R3) mg S/L thiosulfate respectively. The results revealed that adding thiosulfate at the beginning of the anoxic phase promoted sulfur metabolism and increased the proliferation of SRB (mainly Desulfobacter) and SOB (mainly Chromatiaceae). Correspondingly, the relative abundance of GAOs (mainly Candidatus&#95;Competibacter) decreased. After the carbon source was reduced, the abundance of GAOs increased and the competitive activity of SRB was weakened, resulting in the reduced sulfate reduction, which could be attributed to the fact that GAOs had a higher carbon source competitiveness than SRB under low carbon source conditions. While SOB maintained a high abundance due to the addition of thiosulfate as an additional electron donor, which enhanced the denitrification efficiency. Additionally, the dominant SOB shifted from Thiobacillus to Chromatiaceae during the long-term operation, indicating that Chromatiaceae had a higher competitive advantage for reduced sulfur (e.g., S 2 O 3 2- , Polysulfide (Poly-S)) and nitrate compared to Thiobacillus. Furthermore, microbial functional genes revealed that S metabolism was enhanced during long-term operation. The potential mechanism and optimization strategy regarding the competition between sulfur-mediated bacteria and GAOs were revealed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Cyclic AMP is produced in cells by two different types of adenylyl cyclases: at the plasma membrane by the transmembrane adenylyl cyclases (tmACs, ADCY1~ADCY9) and in the cytosol by the evolutionarily more conserved soluble adenylyl cyclase (sAC, ADCY10). By employing high-resolution extracellular flux analysis in HepG2 cells to study glycogen breakdown in real time, we showed that cAMP regulates glycogen metabolism in opposite directions depending on its location of synthesis within cells and the downstream cAMP effectors. While the canonical tmAC-cAMP-PKA signaling promotes glycogenolysis, we demonstrate here that the non-canonical sAC-cAMP-Epac1 signaling suppresses glycogenolysis. Mechanistically, suppression of sAC-cAMP-Epac1 leads to Ser-15 phosphorylation and thereby activation of the liver-form glycogen phosphorylase to promote glycogenolysis. Our findings highlight the importance of cAMP microdomain organization for distinct metabolic regulation and establish sAC as a novel regulator of glycogen metabolism., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ronald Oude Elferink reports financial support was provided by Dutch Cancer Society. Jung-Chin Chang reports financial support was provided by Amsterdam Gastroenterology Endocrinology Metabolism., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Integrative studies are lacking on the responses of digestive enzymes and energy reserves in conjunction with morphological traits at distinct postprandial times in marine estuarine-dependent flatfishes of ecological and economic importance, such as Paralichthys orbignyanus. We determined total weight (TW), hepato-somatic index (IH), activities of digestive enzymes in the intestine, and the concentration of energy reserves in the liver and the muscle at 0, 24, 72, and 360 h after feeding in juveniles of P. orbignyanus. Amylase activity decreased at 72 h (about 30%). Maltase, sucrose, and lipase activities reached peak at 24 h (67%, 600%, and 35%, respectively). Trypsin and aminopeptidase-N activities at 24 and 72 h, respectively, were lower than those at t = 0 (53% and 30%). A peak increase in the concentration of glycogen and triglycerides in the liver (24 h) (86% and 89%, respectively) occurred. In muscle, glycogen and triglyceride concentrations were unchanged at 24 h and higher at 72 and 360 h (100% and 60%). No changes were found in TW, IH, free glucose in the liver and muscle, and protein in the liver. The protein concentration in the muscle sharply increased at 24 and 360 h after feeding (60%). The results indicate a distinct and specific response of central components of carbohydrate, lipid, and protein metabolism that could be adjustments at the biochemical level upon periods of irregular feeding and even of long-term food deprivation inside coastal lagoons or estuaries. The distinct responses of digestive enzymes in the intestine and energy reserves in the liver and muscle suggest the differential modulation of tissue-specific anabolic and catabolic pathways that would allow the maintenance of physical conditions., (© 2023 Fisheries Society of the British Isles.)

Objective: Carbohydrate Response Element Binding Protein (ChREBP) is a glucose 6-phosphate (G6P)-sensitive transcription factor that acts as a metabolic switch to maintain intracellular glucose and phosphate homeostasis. Hepatic ChREBP is well-known for its regulatory role in glycolysis, the pentose phosphate pathway, and de novo lipogenesis. The physiological role of ChREBP in hepatic glycogen metabolism and blood glucose regulation has not been assessed in detail, and ChREBP's contribution to carbohydrate flux adaptations in hepatic Glycogen Storage Disease type 1 (GSD I) requires further investigation., Methods: The current study aimed to investigate the role of ChREBP as a regulator of glycogen metabolism in response to hepatic G6P accumulation, using a model for acute hepatic GSD type Ib. The immediate biochemical and regulatory responses to hepatic G6P accumulation were evaluated upon G6P transporter inhibition by the chlorogenic acid S4048 in mice that were either treated with a short hairpin RNA (shRNA) directed against ChREBP (shChREBP) or a scrambled shRNA (shSCR). Complementary stable isotope experiments were performed to quantify hepatic carbohydrate fluxes in vivo., Results: ShChREBP treatment normalized the S4048-mediated induction of hepatic ChREBP target genes to levels observed in vehicle- and shSCR-treated controls. In parallel, hepatic shChREBP treatment in S4048-infused mice resulted in a more pronounced accumulation of hepatic glycogen and further reduction of blood glucose levels compared to shSCR treatment. Hepatic ChREBP knockdown modestly increased glucokinase (GCK) flux in S4048-treated mice while it enhanced UDP-glucose turnover as well as glycogen synthase and phosphorylase fluxes. Hepatic GCK mRNA and protein levels were induced by shChREBP treatment in both vehicle- and S4048-treated mice, while glycogen synthase 2 (GYS2) and glycogen phosphorylase (PYGL) mRNA and protein levels were reduced. Finally, knockdown of hepatic ChREBP expression reduced starch domain binding protein 1 (STBD1) mRNA and protein levels while it inhibited acid alpha-glucosidase (GAA) activity, suggesting reduced capacity for lysosomal glycogen breakdown., Conclusions: Our data show that ChREBP activation controls hepatic glycogen and blood glucose levels in acute hepatic GSD Ib through concomitant regulation of glucose phosphorylation, glycogenesis, and glycogenolysis. ChREBP-mediated control of GCK enzyme levels aligns with corresponding adaptations in GCK flux. In contrast, ChREBP activation in response to acute hepatic GSD Ib exerts opposite effects on GYS2/PYGL enzyme levels and their corresponding fluxes, indicating that GYS2/PYGL expression levels are not limiting to their respective fluxes under these conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Ice hockey is an intense team sport characterized by repeated bursts of fast-paced skating, rapid changes in speed and direction and frequent physical encounters. These are performed in on-ice shifts of ~30-80 s interspersed with longer sequences of passive recovery, resulting in about 15-25 min on-ice time per player. Nearly 50% of the distance is covered at high-intensity skating speeds and with an accentuated intense activity pattern in forwards compared to defensemen. During ice hockey match-play, both aerobic and anaerobic energy systems are significantly challenged, with the heart rate increasing toward maximum levels during each shift, and with great reliance on both glycolytic and phosphagen ATP provision. The high-intensity activity pattern favors muscle glycogen as fuel, leading to pronounced reductions despite the relatively brief playing time, including severe depletion of a substantial proportion of individual fast- and slow-twitch fibers. Player-tracking suggests that the ability to perform high-intensity skating is compromised in the final stages of a game, which is supported by post-game reductions in repeated-sprint ability. Muscle glycogen degradation, in particular in individual fibers, as well as potential dehydration and hyperthermia, may be prime candidates implicated in exacerbated fatigue during the final stages of a game, whereas multiple factors likely interact to impair exercise tolerance during each shift. This includes pronounced PCr degradation, with potential inadequate resynthesis in a proportion of fast-twitch fibers in situations of repeated intense actions. Finally, the recovery pattern is inadequately described, but seems less long-lasting than in other team sports., (© 2022 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Pompe disease (PD) is a neuromuscular disorder caused by acid α-glucosidase (GAA) deficiency. Reduced GAA activity leads to pathological glycogen accumulation in cardiac and skeletal muscles responsible for severe heart impairment, respiratory defects, and muscle weakness. Enzyme replacement therapy with recombinant human GAA (rhGAA) is the standard-of-care treatment for PD, however, its efficacy is limited due to poor uptake in muscle and the development of an immune response. Multiple clinical trials are ongoing in PD with adeno-associated virus (AAV) vectors based on liver- and muscle-targeting. Current gene therapy approaches are limited by liver proliferation, poor muscle targeting, and the potential immune response to the hGAA transgene. To generate a treatment tailored to infantile-onset PD, we took advantage of a novel AAV capsid able to increase skeletal muscle targeting compared to AAV9 while reducing liver overload. When combined with a liver-muscle tandem promoter (LiMP), and despite the extensive liver-detargeting, this vector had a limited immune response to the hGAA transgene. This combination of capsid and promoter with improved muscle expression and specificity allowed for glycogen clearance in cardiac and skeletal muscles of Gaa -/- adult mice. In neonate Gaa -/- , complete rescue of glycogen content and muscle strength was observed 6 months after AAV vector injection. Our work highlights the importance of residual liver expression to control the immune response toward a potentially immunogenic transgene expressed in muscle. In conclusion, the demonstration of the efficacy of a muscle-specific AAV capsid-promoter combination for the full rescue of PD manifestation in both neonate and adult Gaa -/- provides a potential therapeutic avenue for the infantile-onset form of this devastating disease., (© 2023 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.)

Acute caffeine exposure had been shown to induce hyperglycemia however; the influence of thyroid hormones on the caffeine-induced hyperglycemia is yet to be established. The present study was therefore designed to investigate the effect of caffeine exposure on blood glucose and hepatic glycogen content in thyroidectomized rats. Sixty adult male Wistar rats were randomly divided into 10 groups as I-X (n=6).  Rats in groups I, III, V, VII and IX were given normal saline, caffeine, prazosin + caffeine, propranolol +caffeine, combined prazosin+ propranolol+caffeine injections respectively while rats in groups  II, IV, VI, VIII and X were thyroidectomized  and treated in similar manner as the normal rats respectively. Surgical removal of the thyroid gland was done in the thyroidectomised groups while sham-operation was done in Normal group to serve as control. After healing and following an overnight fast, the rats were anaesthetized and the femoral vein and carotid artery were cannulated for drug administration and blood glucose measurement respectively. After stabilization, following basal measurements, rats from each group were injected normal saline or caffeine (6mg/kg) while another sets were pre-treated prazosin (0.2 mg/kg), propanolol (0.5 mg/kg) or their combination before caffeine administration. Blood glucose was then monitored for 60 minutes post-injection of caffeine at 5 minutes interval. Liver samples were collected at the end of the observation period for glycogen content determination. Caffeine caused significant increased blood glucose levels in both normal and thyroidectomized rats which were up to 210% and 180% respectively at the peak of their responses. Liver glycogen content of the thyroidectomized rats (3.11 ± 0.20 mg/100g tissue weight) was significantly higher than the normal rats (1.91 ± 0.43 mg/100g tissue weight). These glycogen contents were significantly reduced by caffeine in both normal (0.25 ± 0.04 mg/100g tissue weight) and thyroidectomized rats (1.65 ± 0.16 mg/100g tissue weight) when compared with their controls. The caffeine effects on blood glucose and hepatic glycogen content were abolished by pretreatment with propanolol or a combination of prazosin and propanolol in both normal and thyroidectomized rats but pretreatment with prazosin caused only significant reduction in hyperglycemic response to caffeine. The findings of this study suggest that caffeine-induced hyperglycemia in both normal and thyroidectomized rats are mediated through both alpha and beta adrenoceptors.

Background: Artichoke (Cynara scolymus L.) is a typical element of a traditional Mediterranean diet and has potential health advantages for insulin resistance (IR) and type 2 diabetes mellitus (T2DM). This study aims to evaluate the effect and underlying mechanism of artichoke water extract (AWE) on palmitate (PA)-induced IR in human hepatocellular carcinoma (HepG2) cells., Methods: The effect of AWE on cell viability was determined using CCK8 assay. Cellular glucose uptake, glucose consumption, glucose production, and glycogen content were assessed after AWE treatment. The gene expression and protein levels were examined by real-time polymerase chain reaction (qRT-PCR) and western blotting., Results: The results showed that AWE dose-dependently increased cell viability in IR HepG2 cells (P < 0.01). AWE treatment significantly promoted glucose uptake and consumption, decreased glucose production, and increased the cellular glycogen content in IR HepG2 cells (P < 0.01). Mechanistically, AWE elevated the phosphorylation and total protein levels of major insulin signaling molecules in IR HepG2 cells, which resulted in a decrease in the expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) and the inhibition of glycogen synthase (GS) phosphorylation in IR HepG2 cells. Furthermore, the protective effect of AWE on IR HepG2 cells might be ascribed to the inhibition of the endoplasmic reticulum (ER) stress., Conclusion: We conclude that AWE may improve glucose metabolism by regulating IRS1/PI3K/AKT/FoxO1 and GSK-3β signaling associated with the inhibition of ER stress in IR HepG2 cells induced by PA., (© 2023. The Author(s).)

Embryogenesis is highly dependent on maternally loaded materials, particularly those used for energy production. Different environmental conditions and genetic backgrounds shape embryogenesis. The robustness of embryogenesis in response to extrinsic and intrinsic changes remains incompletely understood. By analyzing the levels of two major nutrients, glycogen and neutral lipids, we discovered stage-dependent usage of these two nutrients along with mitochondrial morphology changes during Caenorhabditis elegans embryogenesis. ATGL, the rate-limiting lipase in cellular lipolysis, is expressed and required in the hypodermis to regulate mitochondrial function and support embryogenesis. The embryonic lethality of atgl-1 mutants can be suppressed by reducing sinh-1/age-1-akt signaling, likely through modulating glucose metabolism to maintain sustainable glucose consumption. The embryonic lethality of atgl-1(xd314) is also affected by parental nutrition. Parental glucose and oleic acid supplements promote glycogen storage in atgl-1(xd314) embryos to compensate for the impaired lipolysis. The rescue by parental vitamin B12 supplement is likely through enhancing mitochondrial function in atgl-1 mutants. These findings reveal that metabolic plasticity contributes to the robustness of C. elegans embryogenesis., (© 2023 The Authors.)

The maternal liver is challenged by metabolic demands throughout pregnancy. However, hepatocyte dynamics and their physiological significance in pregnancy remain unclear. Here, we show in mice that hepatocyte proliferation is spatiotemporally regulated in each liver lobular zone during pregnancy, with transient proliferation of periportal and pericentral hepatocytes during mid and late gestation, respectively. Using adeno-associated virus (AAV)-8-mediated expression of the cell cycle inhibitor p21 in hepatocytes, we show that inhibition of hepatocyte proliferation during mid, but not late, gestation impairs liver growth. Transcriptionally, genes involved in glucose/glycogen metabolism are downregulated in late pregnancy when midgestational hepatocyte proliferation is attenuated. In addition, hepatic glycogen storage is abolished, with concomitant elevated blood glucose concentrations, glucose intolerance, placental glycogen deposition, and fetal overgrowth. Laser capture microdissection and RNA-seq analysis of each liver lobular zone show zone-specific changes in the transcriptome during pregnancy and identify genes that are periportally expressed at midgestation, including the hyaluronan-mediated motility receptor (Hmmr). Knockdown of Hmmr in hepatocytes by AAV8-shHmmr suppresses periportal hepatocyte proliferation at midgestation and induces impaired hepatic glycogen storage, glucose intolerance, placental glycogen deposition and fetal overgrowth. Our results suggest that periportal hepatocyte proliferation during midgestation is critical for maternal glycogen metabolism and fetal size., (© 2023. The Author(s).)

Objective: Under physiological conditions, astrocytes produce lactate to meet the increased synaptic energy demand due to neuronal activity. In the light of the findings showing that this process is disrupted in the pathophysiology of major depression, the aim of this study is to investigate the effect of pharmacological inhibition of perisynaptic astrocyte glycogen utilization on anxiety-like behavior and depression-like behavior in female and male mice., Methods: In this study, DAB (1,4-dideoxy-1,4-imino-D-arabinitol), which is an inhibitor of glycogen breaking enzyme glycogen phosphorylase, was intrahippocampally administered to 15 female and 14 male Swiss albino mice, while 15 female and 12 male Swiss albino mice received intrahippocampal saline injections. Three and five days after the injections, the anxiety-like and depression-like behaviors of the mice were assessed by locomotor activity, open-field test, light-dark box test, tail suspension test and sucrose preference test., Results: Three days after injection, neither depression-like nor anxietylike significant behavioral changes were detected in the male experimental group mice compared to the control group; but an increase in locomotor activity (p=0.05) and time spent in the open-field (p=0.01) were observed on the fifth day. In evaluations of the female experimental group mice on the third and fifth days, depression-like and anxiety-like behaviors were found similar to the control group, as seen in the male mice. The only significant difference in the experimental group female mice was found in the sucrose preference test, which revealed an increased tendency to prefer sucrose (p=0.003) compared to the control group., Conclusion: The inhibition of glycogen use in the hippocampus by DAB did not affect anxiety-like and depression-like behaviors 3 and 5 days after injection in both female and male mice. The increase in the time spent in the open-field by male experimental group mice was associated not with anxiety, but with increase in the locomotor activity. The fact that no significant difference was observed in the light-dark box test, which is another test used to evaluate anxiety, supported this opinion. The increase seen in the sucrose preference test in female experimental group mice was not interpreted as an increase in hedonic behavior because prevention of glycogen breakdown in the hypothalamus might have homeostatically increased sugar-craving and therefore resulted in an increase in sucrose preference. Different set of tests better targeting the energy and glucose metabolism and applied at farther time points than surgery are recommended for future studies.

Melatonin is a multifunctional bioactive molecule present in almost all organisms and has been gradually used in the aquaculture industry in recent years. Energy metabolism is an essential process for individuals to maintain their life activities; however, the process through which melatonin regulates energy metabolism in aquatic animals remains unclear. The present study aimed to conduct a comprehensive analysis of the regulatory mechanism of melatonin for energy metabolism in Cherax destructor by combining metabolomics analysis with the detection of the key substance content, enzymatic activity, and gene expression levels in the energy metabolism process after culturing with dietary melatonin supplementation for 8 weeks. Our results showed that dietary melatonin increased the content of glycogen, triglycerides, and free fatty acids; decreased lactate levels; and promoted the enzymatic activity of pyruvate kinase (PK), malate dehydrogenase (MDH), and acetyl-CoA carboxylase. The results of gene expression analysis showed that dietary melatonin also increased the expression levels of hexokinase, PK, MDH, lactate dehydrogenase, lipase, and fatty acid synthase genes. The results of metabolomics analysis showed that differentially expressed metabolites were significantly enriched in lysine degradation and glycerophospholipid metabolism. In conclusion, our study demonstrates that dietary melatonin increased oxidative phosphorylation, improved glucose utilization, and promoted storage of glycogen and lipids in C. destructor. These lipids are used not only for energy storage but also to maintain the structure and function of cell membranes. Our results further add to the understanding of the mechanisms of energy regulation by melatonin in crustaceans., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Evidence has demonstrated that oxidative stress plays a crucial role in regulating cellular glucose metabolism. In previous studies, wheat germ peptide (WGP) was found to effectively mitigate oxidative stress induced by high glucose. Based on the information provided, we hypothesized that WGP could exhibit antihyperglycemic and anti-insulin-resistant effects in cells. The insulin-resistant cell model was established by insulin stimulation. The glucose consumption, glycogen content, and the activities of hexokinase and pyruvate kinase following WGP treatment were measured. The protein expression of SOCS3, phosphorylated insulin receptor substrate-1 (p-IRS1), IRS1, phosphorylated protein kinase B (p-Akt), Akt, glucose transporter 2 (GLUT2), phosphorylated GSK 3β, GSK 3β, FOXO1, G6P, and phosphoenolpyruvate carboxykinase were assessed by western blot analysis. Our results demonstrated that WGP treatment increased cellular glucose consumption and glycogen synthesis and enhanced hexokinase and pyruvate kinase activities. Additionally, WGP treatment was observed to cause a significant reduction in the expression of SOCS3, FOXO1, G6P, and phosphoenolpyruvate carboxykinase, as well as in the ratio of p-IRS1/IRS1. Conversely, the expression of GLUT2 and the ratios of p-Akt/Akt and p-GSK3β/GSK3β were upregulated by WGP. These findings suggested that WGP can activate the SOCS3/IRS1/Akt signaling pathway, thus promoting the phosphorylation of GSK-3β and increasing the expression of FOXO1 and GLUT2, which contribute to enhancing glycogen synthesis, inhibiting gluconeogenesis, and promoting glucose transport in insulin-resistant HepG2 cells., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Exercise mimetics is a proposed class of therapeutics that specifically mimics or enhances the therapeutic effects of exercise. Muscle glycogen and lactate extrusion are critical for physical performance. The mechanism by which glycogen and lactate metabolism are manipulated during exercise remains unclear. This study aimed to assess the effect of miR-92b on the upregulation of exercise training-induced physical performance., Methods: Adeno-associated virus (AAV)-mediated skeletal muscle miR-92b overexpression in C57BLKS/J mice, and global knockout of miR-92b mice were used to explore the function of miR-92b in glycogen and lactate metabolism in skeletal muscle. AAV-mediated UGP2 or MCT4 knockdown in WT or miR-92 knockout mice was used to confirm whether miR-92b regulates glycogen and lactate metabolism in skeletal muscle through UGP2 and MCT4. Body weight, muscle weight, grip strength, running time and distance to exhaustion, and muscle histology were assessed. The expression levels of muscle mass-related and function-related proteins were analysed by immunoblotting or immunostaining., Results: Global knockout of miR-92b resulted in normal body weight and insulin sensitivity, but higher glycogen content before exercise exhaustion (0.8538 ± 0.0417 vs. 1.043 ± 0.040, **P = 0.0087), lower lactate levels after exercise exhaustion (4.133 ± 0.2589 vs. 3.207 ± 0.2511, *P = 0.0279), and better exercise capacity (running distance to exhaustion, 3616 ± 86.71 vs. 4231 ± 90.29, ***P = 0.0006; running time to exhaustion, 186.8 ± 8.027 vs. 220.8 ± 3.156, **P = 0.0028), as compared with those observed in the control mice. Mice skeletal muscle overexpressing miR-92b (both miR-92b-3p and miR-92b-5p) displayed lower glycogen content before exercise exhaustion (0.6318 ± 0.0231 vs. 0.535 ± 0.0194, **P = 0.0094), and higher lactate accumulation after exercise exhaustion (4.5 ± 0.2394 vs. 5.467 ± 0.1892, *P = 0.01), and poorer exercise capacity (running distance to exhaustion, 4005 ± 81.65 vs. 3228 ± 149.8, ***P<0.0001; running time to exhaustion, 225.5 ± 7.689 vs. 163 ± 6.476, **P = 0.001). Mechanistic analysis revealed that miR-92b-3p targets UDP-glucose pyrophosphorylase 2 (UGP2) expression to inhibit glycogen synthesis, while miR-92b-5p represses lactate extrusion by directly target monocarboxylate transporter 4 (MCT4). Knockdown of UGP2 and MCT4 reversed the effects observed in the absence of miR-92b in vivo., Conclusions: This study revealed regulatory pathways, including miR-92b-3p/UGP2/glycogen synthesis and miR-92b-5p/MCT4/lactate extrusion, which could be targeted to control exercise capacity., (© 2023 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by Wiley Periodicals LLC.)

Although the presence of glycogen in platelets was established in the 1960s, its importance to specific functions ( i.e ., activation, secretion, aggregation, and clot contraction) remains unclear. Patients with glycogen storage disease often present with increased bleeding and glycogen phosphorylase (GP) inhibitors, when used as treatments for diabetes, induce bleeding in preclinical studies suggesting some role for this form of glucose in hemostasis. In the present work, we examined how glycogen mobilization affects platelet function using GP inhibitors (CP316819 and CP91149) and a battery of ex vivo assays. Blocking GP activity increased glycogen levels in resting and thrombin-activated platelets and inhibited platelet secretion and clot contraction, with minimal effects on aggregation. Seahorse energy flux analysis and metabolite supplementation experiments suggested that glycogen is an important metabolic fuel whose role is affected by platelet activation and the availability of external glucose and other metabolic fuels. Our data shed light on the bleeding diathesis in glycogen storage disease patients and offer insights into the potential effects of hyperglycemia on platelets.

Introduction: Glycogen storage disease type VI (GSD VI) is a disorder of glycogen metabolism due to mutations in the PYGL gene. Patients with GSD VI usually present with hepatomegaly, recurrent hypoglycemia, and short stature. Results: We report on two non-related Turkish patients with a novel homozygous splice site variant, c.345G>A, which was shown to lead to exon 2 skipping of the PYGL-mRNA by exome and transcriptome analysis. According to an in silico analysis, deletion Arg82_Gln115del is predicted to impair protein stability and possibly AMP binding. Conclusion: GSD VI is a possibly underdiagnosed disorder, and in the era of next generation sequencing, more and more patients with variants of unknown significance in the PYGL-gene will be identified. Techniques, such as transcriptome analysis, are important tools to confirm the pathogenicity and to determine therapeutic measures based on genetic results.

The purpose of this study was to investigate differences in glycogen metabolism (glycogen synthesis and glycolysis) between dysplastic/malignant (iodine-negative) and normal (iodine-positive) oral epithelial tissue. Twenty-two frozen samples of iodine-positive and -negative mucosal tissue were obtained from 22 oral squamous cell carcinoma (OSCC) patients. Serial frozen sections were cut and analyzed using hematoxylin-eosin and periodic acid-Schiff methods and immunohistochemical (IHC) staining for glucokinase (GK), phosphoglucomutase 3 (PGM3), and glucose-6-phosphatase (G6 Pase) to investigate glycogen metabolism. The expression levels of metabolites in OSCC and normal oral epithelial tissue were subjected to a metabolome analysis to clarify differences in central carbon metabolism, including glycogen metabolism. No significant differences were observed in GK or PGM3 immunoactivity between iodine-positive and -negative areas. However, G6 Pase immunoreactivity was significantly stronger in the upper layers of the negative epithelium. In the metabolome analysis, significant differences were noted in the last half of glycolysis. Lactic acid as the final metabolite in glycolysis was detected in the dysplastic/cancerous oral epithelium, and its levels were slightly higher than those in the normal epithelium. G6 Pase expression was significantly strong in dysplastic/cancerous oral epithelial cells. Dysplastic/cancerous oral epithelial cells exhibited stronger activation for glucose metabolism. The results of the metabolome analysis suggest that glucose and glycogen degradation products in oral dysplastic/cancerous epithelial cells are used for nucleic acid synthesis through the pentose phosphate pathway. [ABSTRACT FROM AUTHOR]

Integrin-linked kinase (ILK) is a critical intracellular signaling node for integrin receptors. Its role in liver development is complex, as ILK deletion at E10.5 (before hepatocyte differentiation) results in biochemical and morphological differences that resolve as mice age. Nevertheless, mice with ILK depleted specifically in hepatocytes are protected from the hepatic insulin resistance during obesity. Despite the potential importance of hepatocyte ILK to metabolic health, it is unknown how ILK controls hepatic metabolism or glucoregulation. The present study tested the role of ILK in hepatic metabolism and glucoregulation by deleting it specifically in hepatocytes, using a cre-lox system that begins expression at E15.5 (after initiation of hepatocyte differentiation). These mice develop the most severe morphological and glucoregulatory abnormalities at 6 wk, but these gradually resolve with age. After identifying when the deletion of ILK caused a severe metabolic phenotype, in depth studies were performed at this time point to define the metabolic programs that coordinate control of glucoregulation that are regulated by ILK. We show that 6-wk-old ILK-deficient mice have higher glucose tolerance and decreased net glycogen synthesis. Additionally, ILK was shown to be necessary for transcription of mitochondrial-related genes, oxidative metabolism, and maintenance of cellular energy status. Thus, ILK is required for maintaining hepatic transcriptional and metabolic programs that sustain oxidative metabolism, which are required for hepatic maintenance of glucose homeostasis. [ABSTRACT FROM AUTHOR]

Circadian clocks generate rhythms in cellular functions, including metabolism, to align biological processes with the 24-hour environment. Disruption of this alignment by shift work alters glucose homeostasis. Glucose homeostasis depends on signaling and allosteric control; however, the molecular mechanisms linking the clock to glucose homeostasis remain largely unknown. We investigated the molecular links between the clock and glycogen metabolism, a conserved glucose homeostatic process, in Neurospora crassa. We find that glycogen synthase (gsn) mRNA, glycogen phosphorylase (gpn) mRNA, and glycogen levels, accumulate with a daily rhythm controlled by the circadian clock. Because the synthase and phosphorylase are critical to homeostasis, their roles in generating glycogen rhythms were investigated. We demonstrate that while gsn was necessary for glycogen production, constitutive gsn expression resulted in high and arrhythmic glycogen levels, and deletion of gpn abolished gsn mRNA rhythms and rhythmic glycogen accumulation. Furthermore, we show that gsn promoter activity is rhythmic and is directly controlled by core clock component white collar complex (WCC). We also discovered that WCC-regulated transcription factors, VOS-1 and CSP-1, modulate the phase and amplitude of rhythmic gsn mRNA, and these changes are similarly reflected in glycogen oscillations. Together, these data indicate the importance of clock-regulated gsn transcription over signaling or allosteric control of glycogen rhythms, a mechanism that is potentially conserved in mammals and critical to metabolic homeostasis. [ABSTRACT FROM AUTHOR]

Highlights • Glycolysis in Entamoeba uses pyrophosphate as high-energy phospho group donor. • Pyrophosphate derived from anabolism is insufficient for a PPi-dependent glycolysis. • E. histolytica produces 2–3.5 ATP, instead of 5 ATP per glucose catabolized. • The main controlling steps are glucose transport, glycogen metabolism, PGAM and ADHE. • The main flux-controlling reactions are the most adequate therapeutic targets. Abstract Entamoeba histolytica has neither Krebs cycle nor oxidative phosphorylation activities; therefore, glycolysis is the main pathway for ATP supply and provision of carbon skeleton precursors for the synthesis of macromolecules. Glucose is metabolized through fermentative glycolysis, producing ethanol as its main end-product as well as some acetate. Amoebal glycolysis markedly differs from the typical Embden-Meyerhof-Parnas pathway present in human cells: (i) by the use of inorganic pyrophosphate, instead of ATP, as the high-energy phospho group donor; (ii) with one exception, the pathway enzymes can catalyze reversible reactions under physiological conditions; (iii) there is no allosteric regulation and sigmoidal kinetic behavior of key enzymes; and (iv) the presence of some glycolytic and fermentation enzymes similar to those of anaerobic bacteria. These peculiarities bring about alternative mechanisms of control and regulation of the PPi-dependent fermentative glycolysis in the parasite in comparison to the ATP-dependent and allosterically regulated glycolysis in many other eukaryotic cells. In this review, the current knowledge of the carbohydrate metabolism enzymes in E. histolytica is analyzed. Thermodynamics and stoichiometric analyses indicate 2 to 3.5 ATP yield per glucose metabolized, instead of the often presumed 5 ATP/glucose ratio. PPi derived from anabolism seems insufficient for PPi-glycolysis; hence, alternative ways of PPi supply are also discussed. Furthermore, the underlying mechanisms of control and regulation of the E. histolytica carbohydrate metabolism, analyzed by applying integral and systemic approaches such as Metabolic Control Analysis and kinetic modeling, contribute to unveiling alternative and promising drug targets. [ABSTRACT FROM AUTHOR]