bims-glecem 2022-05-15 papers

bims-glecem

Biomed News

on Glycogen metabolism in exercise, cancer and energy metabolism

Issue of 2022–05–15
27 papers selected by
Dipsikha Biswas, Københavns Universitet

High-fat/high-carbohydrate diet increases glycogen accumulation in lung tissue in vivo.
Prediction of binding affinity of 1,2-diphenyline ketone analogues at adenosine triphosphate binding site of glycogen synthase kinase-3β: a molecular docking and dynamic simulation study.
Role of Glycogen Synthase Kinase-3 in Interferon-γ-Mediated Immune Hepatitis.
Understanding the role of SGLT2 inhibitors in glycogen storage disease type Ib: the experience of one UK centre.
Development of a Novel ELISA for Sensitive Quantitation of Glycogen and Polyglucosan Bodies.
A very rare case report of glycogen storage disease type IXc with novel PHKG2 variants.
Glycogen Storage Disease Phenotypes Accompanying the Perturbation of the Methionine Cycle in NDRG3-Deficient Mouse Livers.
Identification of Potential Muscle Biomarkers in McArdle Disease: Insights from Muscle Proteome Analysis.
GAA Deficiency Disrupts Distal Airway Cells in Pompe Disease.
Effect of Pulicaria mauritanica on Glucose Metabolism and glycogen Content in Streptozotocin-Induced Diabetic Rats.
Mass Spectrometry Imaging Reveals Distinct Differences in Glycogen Accumulation in Lung Tumors from Appalachian Patients.
Combined effects of exercise training and D-allulose intake on endurance capacity in mice.
Elucidating the Role of Glycogen in Glucose Transporter 1 Deficiency Syndrome.
Glycogen Storage Disease type IA refractory to cornstarch: Can next generation sequencing offer a solution?
Melatonin Potentiates Exercise-Induced Increases in Skeletal Muscle PGC-1α and Optimizes Glycogen Replenishment.
Hypoglossal Motoneuron (XII MN) Survival Over the Lifespan in Pompe Disease.
Aberrant glycogen accumulation alters gene expression and promotes lung tumor progression in vivo.
The Yeast Glycogen Synthase Kinase Homolog Rim11 Phosphorylates the Phosphatidic Acid Phosphatase Pah1 to Inhibit its Catalytic Activity.
Approach to the diagnosis of metabolic myopathies.
Upregulation of BRD7 protects podocytes against high glucose-induced apoptosis by enhancing Nrf2 in a GSK-3β-dependent manner.
Classic infantile-onset Pompe disease with histopathological neurologic findings linked to a novel GAA gene 4 bp deletion: A case study.
Multiple Freeze-thaw Cycles in Cope's Gray Treefrog Dryophytes chrysoscelis Reveal Novel Physiological, Biochemical, and Morphological Insights into Vertebrate Freeze Tolerance.
A Case of a Mild Clinical Phenotype with Myopathic and Hemolytic Forms of Phosphoglycerate Kinase Deficiency (PGK Osaka): A Case Report and Literature Review.
Pharmacological Evaluation of Beta-Hydroxifosphocarnitine in No-Alcoholic Esteatohepatitis Induced in Rats.
Effect of Starch Primers on the Fine Structure of Enzymatically Synthesized Glycogen-like Glucan.
Electrical Stimulated Glut4 Trafficking Reduces Critical Illness-Associated Muscle Wasting.
Sevoflurane suppresses NLRP3 inflammasome-mediated pyroptotic cell death to attenuate lipopolysaccharide-induced acute lung injury through inducing GSK-3β phosphorylation and activation.

FASEB J. 2022 May;36 Suppl 1

High-fat/high-carbohydrate diet increases glycogen accumulation in lung tissue in vivo.

Alexis N James, Lindsey R Conroy, Tara R Hawkinson, Josephine E Chang, Elena C Manauis, Jessica F Lamb, Michael D Buoncristiani, Lyndsay E A Young, Christine Filmore Brainson, Ramon C Sun.

Lung adenocarcinoma (LUAD) is the major histological subgroup of non-small cell lung cancer (NSCLC) with an extremely high mortality rate even when diagnosed at an early stage. LUAD makes up around 40% of lung cancer cases and can quickly metastasize to other areas of the body. Glycogen is the short-term storage of carbohydrates and can be easily mobilized in the body. Recently, other and our own data suggests glycogen can drive lung cancer progression, however, the mechanism of which glycogen accumulates in LUAD is poorly understood and potentially arises from a number of genetic and environmental factors. Although specific genetic variants driving aberrant LUAD glycogen accumulation have been identified, several studies have shown that caloric excess as well as specific nutrients in the diet can promote tumor growth. Further, LUAD patients with type II diabetes or high BMI have significantly poorer survival. Therefore, we hypothesized that a diet rich in fats and carbohydrates that mimics a Western diet increases glycogen accumulation in lung tissue and potentially drives LUAD tumor progression. To test our hypothesis that a Western diet alters glycogen metabolism independent of genetic drivers and tumor formation, we administered via oral gavage a Western diet comprised of corn oil and high fructose corn syrup (150 μl corn oil: 25% high-fructose corn syrup solution) to wild-type C57BL/6 mice at acute (1-, 3-, and 6-hours) and chronic (two weeks) time points. At the end of each time point, mice were sacrificed and lung tissue was harvested. Using a combination of gas chromatography mass spectrometry (GCMS) and matrix-assisted laser desorption ionization mass spectrometry imaging, we quantified central carbon metabolites and glycogen content in lung tissue resected from these mice. Mice administered H2O were used as a control. We found that the mice administered a Western diet for two weeks exhibited elevated levels of glycogen as well as metabolite pools within glycolysis and the TCA cycle in lung tissue compared to the control group. However, our acute studies revealed no change in lung glycogen up to 6-hours after receiving the Western diet. Overall, these data highlight a link between diet and glycogen metabolism in the lung and suggest that intake of different dietary nutrients may play a role in glycogen accumulation in LUAD tumors and disease progression. Our results demonstrate that a high fat/high carbohydrate diet in wild-type mice increases central carbon metabolism and glycogen accumulation in lung tissue after chronic exposure. Moving forward, we will examine the contribution of diet to glycogen metabolism in a mouse of LUAD and assess the effect of increased glycogen accumulation on tumor growth in vivo.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R2115
J Biomol Struct Dyn. 2022 May 11. 1-16

Prediction of binding affinity of 1,2-diphenyline ketone analogues at adenosine triphosphate binding site of glycogen synthase kinase-3β: a molecular docking and dynamic simulation study.

Subramaniyan Dinakar, Mani Gurubarath, Karthik Dhananjayan.

  Glycogen synthase kinase (GSK)-3β is one of the downstream signalling molecules involved in phosphorylation of glycogen synthase, a key enzyme involved in the synthesis of glycogen from glucose. GSK-3β regulate some of the critical processes underlying structural and functional synaptic plasticity of neurons. Down regulation or inhibition of GSK-3β enhances long-term potentiation and cognitive functions in animal models of Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. A number of compounds are available to inhibit GSK-3β, however none of them are in clinical practice to treat neurodegenerative diseases. The aim of our study was to predict the molecular interaction and dynamic behaviour of naturally occurring 1,2-diphenyline ketone analogues at the adenosine triphosphate binding site of glycogen synthase kinase (GSK)-3β through simulation studies. Out of all 1,2-diphenyline ketone analogues,1, 3, 5, 6-Tetrahydroxyxanthone (Rank = 1), Secalonic acid F (Rank = 2), and Trihydroxy-2-(2,3-dihydroxy-3-methylbutyl)-7-methoxy-8-(3-methyl-2-butenyl) xanthone (Rank = 3) were found to exhibit lowest docking score of -12.07, -11.49, and -11.24 kcal/mol with dissociation constant of 1.37, 3.84, and 5.99 nM, respectively. The molecular dynamic simulation of rank 1 and rank 3 ligands indicated stable interaction throughout the simulation and interaction analyses has shown that the presence of hydroxyl groups at C1, C3, C5, and C6 around 1,2 diphenyline ketone nucleus to influence their binding affinity at the ATP-binding site of GSK-3β. We predicted that 1,3,5,6-Tetrahydroxyxanthone and 1, 3, 6-Trihydroxy-2-(2,3-dihydroxy-3-methylbutyl)-7-methoxy-8-(3-methyl-2-butenyl) xanthone may act as a potential ligand or lead compound to inhibit GSK-3β and also may play an important role in alleviating neurodegenerative diseases.Communicated by Ramaswamy H. Sarma.

Keywords:  1,2-diphenyline ketone analogues; amyotrophic lateral sclerosis; glycogen synthase kinase 3β; molecular dynamic simulation; xanthonoids

DOI:  https://doi.org/10.1080/07391102.2022.2074143
Int J Mol Sci. 2022 Apr 23. pii: 4669. [Epub ahead of print]23(9):

Role of Glycogen Synthase Kinase-3 in Interferon-γ-Mediated Immune Hepatitis.

Chia-Ling Chen, Po-Chun Tseng, Rahmat Dani Satria, Thi Thuy Nguyen, Cheng-Chieh Tsai, Chiou-Feng Lin.

  Glycogen synthase kinase-3 (GSK-3), a serine/threonine kinase, is a vital glycogen synthase regulator controlling glycogen synthesis, glucose metabolism, and insulin signaling. GSK-3 is widely expressed in different types of cells, and its abundant roles in cellular bioregulation have been speculated. Abnormal GSK-3 activation and inactivation may affect its original bioactivity. Moreover, active and inactive GSK-3 can regulate several cytosolic factors and modulate their diverse cellular functional roles. Studies in experimental liver disease models have illustrated the possible pathological role of GSK-3 in facilitating acute hepatic injury. Pharmacologically targeting GSK-3 is therefore suggested as a therapeutic strategy for liver protection. Furthermore, while the signaling transduction of GSK-3 facilitates proinflammatory interferon (IFN)-γ in vitro and in vivo, the blockade of GSK-3 can be protective, as shown by an IFN-γ-induced immune hepatitis model. In this study, we explored the possible regulation of GSK-3 and the potential relevance of GSK-3 blockade in IFN-γ-mediated immune hepatitis.

Keywords:  glycogen synthase kinase-3; immune hepatitis; interferon-γ; liver

DOI:  https://doi.org/10.3390/ijms23094669
Orphanet J Rare Dis. 2022 May 12. 17(1): 195

Understanding the role of SGLT2 inhibitors in glycogen storage disease type Ib: the experience of one UK centre.

Rebecca K Halligan, R Neil Dalton, Charles Turner, Katherine A Lewis, Helen R Mundy.

   BACKGROUND: Glycogen storage disease type Ib (GSD Ib) is a severe disorder of carbohydrate metabolism due to bi-allelic variants in SLC37A4. It is associated with neutropaenia and neutrophil dysfunction, which has recently been attributed to the accumulation of 1,5-anhydroglucitol-6-phosphate (1,5AG6P) within neutrophils. Treatment with sodium-glucose co-transporter-2 (SGLT2) inhibitors, such as empagliflozin, is a novel therapy that reduces 1,5-anhydroglucitol (1,5AG) in plasma.
RESULTS: We report our experience in treating 8 paediatric GSD Ib patients with empagliflozin with a cumulative treatment time greater than 12 years. Treatment with a median dose of 5 mg (0.22 mg/kg height weight) of empagliflozin resulted in improvement in bowel health, growth, and laboratory parameters. Plasma 1,5AG levels reduced by a median of 78%. Baseline 1,5AG levels in our cohort were higher than in adult patients with GSD Ib. Hypoglycaemia on empagliflozin treatment occurred in 50% of our cohort.
CONCLUSION: We report the largest single centre cohort of GSD Ib patients treated with empagliflozin to date. Treatment with SGLT2 inhibitors is a novel and favourable treatment option for neutropaenia and neutrophil dysfunction in GSD Ib. We suggest a low starting dose of empagliflozin with careful titration due to the risk of hypoglycaemia. The interpretation of 1,5AG levels and their role in treatment monitoring is yet to be established, and requires ongoing research.

Keywords:  1,5-Anhydroglucitol; Empagliflozin; Glycogen storage disease type Ib; Neutropaenia; Neutrophil dysfunction; SGLT2 inhibitors

DOI:  https://doi.org/10.1186/s13023-022-02345-2
FASEB J. 2022 May;36 Suppl 1

Development of a Novel ELISA for Sensitive Quantitation of Glycogen and Polyglucosan Bodies.

Alex R Cantrell, Elena Manauis, Maddison Webb, Alberto Rondon, Ronald C Bruntz, Ramon C Sun, Craig W Vander Kooi, Matthew S Gentry.

Many glycogen storage diseases, e.g., Lafora disease and Pompe disease, are characterized by aberrant glycogen-like aggregates known as polyglucosan bodies (PGBs). Despite the clinical relevance of PGB accumulation, there are limited options to rapidly assess PGB levels in tissues and biofluids. Additionally, there are limitations to current pre-clinical methods that rely on enzymatic degradation assays and mass spectrometry in quantitating PGBs. We recently developed novel sandwich ELISAs for the quantitation of both glycogen and PGBs. By utilizing the specificities of glycogen and PGB antibodies, we can specifically capture glycogen or PGBs and detect them utilizing a unique carbohydrate binding module (CBM). We establish the specificity of the assays and the sensitivity of the sandwich ELISAs compared to other techniques used for quantitation. We also demonstrate the applicability of the ELISA using multiple mouse models of Lafora disease and Pompe disease to quantify PGB loads in the brain. Moving forward, these ELISAs could be used in both research and clinical settings to accurately determine PGB levels.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R2533
BMC Pediatr. 2022 May 12. 22(1): 267

A very rare case report of glycogen storage disease type IXc with novel PHKG2 variants.

Yongxian Shao, Taolin Li, Minyan Jiang, Jianan Xu, Yonglan Huang, Xiuzhen Li, Ruidan Zheng, Li Liu.

   BACKGROUND: Pathogenic mutations in the PHKG2 are associated with a very rare disease-glycogen storage disease IXc (GSD-IXc)-and are characterized by severe liver disease.
CASE PRESENTATION: Here, we report a patient with jaundice, hypoglycaemia, growth retardation, progressive increase in liver transaminase and prominent hepatomegaly from the neonatal period. Genetic testing revealed two novel, previously unreported PHKG2 mutations (F233S and R320DfsX5). Functional experiments indicated that both F223S and R320DfsX5 lead to a decrease in key phosphorylase b kinase enzyme activity. With raw cornstarch therapy, hypoglycaemia and lactic acidosis were ameliorated and serum aminotransferases decreased.
CONCLUSION: These findings expand the gene spectrum and contribute to the interpretation of clinical presentations of these two novel PHKG2 mutations.

Keywords:  Case report; Glycogen storage disease; PHKG2; Phosphorylase b kinase

DOI:  https://doi.org/10.1186/s12887-021-03055-7
Cells. 2022 May 04. pii: 1536. [Epub ahead of print]11(9):

Glycogen Storage Disease Phenotypes Accompanying the Perturbation of the Methionine Cycle in NDRG3-Deficient Mouse Livers.

Hyun Ahm Sohn, Dong Chul Lee, Anna Park, Minho Kang, Byoung-Ha Yoon, Chul-Ho Lee, Yong-Hoon Kim, Kyoung-Jin Oh, Cha Yeon Kim, Seong-Hwan Park, Han Koo, Hyoung-Chin Kim, Won Kee Yoon, Dae-Sik Lim, Daesoo Kim, Kyung Chan Park, Young Il Yeom.

  N-Myc downstream regulated gene 3 (NDRG3) is a unique pro-tumorigenic member among NDRG family genes, mediating growth signals. Here, we investigated the pathophysiological roles of NDRG3 in relation to cell metabolism by disrupting its functions in liver. Mice with liver-specific KO of NDRG3 (Ndrg3 LKO) exhibited glycogen storage disease (GSD) phenotypes including excessive hepatic glycogen accumulation, hypoglycemia, elevated liver triglyceride content, and several signs of liver injury. They suffered from impaired hepatic glucose homeostasis, due to the suppression of fasting-associated glycogenolysis and gluconeogenesis. Consistently, the expression of glycogen phosphorylase (PYGL) and glucose-6-phosphate transporter (G6PT) was significantly down-regulated in an Ndrg3 LKO-dependent manner. Transcriptomic and metabolomic analyses revealed that NDRG3 depletion significantly perturbed the methionine cycle, redirecting its flux towards branch pathways to upregulate several metabolites known to have hepatoprotective functions. Mechanistically, Ndrg3 LKO-dependent downregulation of glycine N-methyltransferase in the methionine cycle and the resultant elevation of the S-adenosylmethionine level appears to play a critical role in the restructuring of the methionine metabolism, eventually leading to the manifestation of GSD phenotypes in Ndrg3 LKO mice. Our results indicate that NDRG3 is required for the homeostasis of liver cell metabolism upstream of the glucose-glycogen flux and methionine cycle and suggest therapeutic values for regulating NDRG3 in disorders with malfunctions in these pathways.

Keywords:  GNMT; NDRG3; PYGL; glycogen storage disease; methionine cycle; reprogramming

DOI:  https://doi.org/10.3390/cells11091536
Int J Mol Sci. 2022 Apr 22. pii: 4650. [Epub ahead of print]23(9):

Identification of Potential Muscle Biomarkers in McArdle Disease: Insights from Muscle Proteome Analysis.

Inés García-Consuegra, Sara Asensio-Peña, Rocío Garrido-Moraga, Tomàs Pinós, Cristina Domínguez-González, Alfredo Santalla, Gisela Nogales-Gadea, Pablo Serrano-Lorenzo, Antoni L Andreu, Joaquín Arenas, José L Zugaza, Alejandro Lucia, Miguel A Martín.

  Glycogen storage disease type V (GSDV, McArdle disease) is a rare genetic myopathy caused by deficiency of the muscle isoform of glycogen phosphorylase (PYGM). This results in a block in the use of muscle glycogen as an energetic substrate, with subsequent exercise intolerance. The pathobiology of GSDV is still not fully understood, especially with regard to some features such as persistent muscle damage (i.e., even without prior exercise). We aimed at identifying potential muscle protein biomarkers of GSDV by analyzing the muscle proteome and the molecular networks associated with muscle dysfunction in these patients. Muscle biopsies from eight patients and eight healthy controls showing none of the features of McArdle disease, such as frequent contractures and persistent muscle damage, were studied by quantitative protein expression using isobaric tags for relative and absolute quantitation (iTRAQ) followed by artificial neuronal networks (ANNs) and topology analysis. Protein candidate validation was performed by Western blot. Several proteins predominantly involved in the process of muscle contraction and/or calcium homeostasis, such as myosin, sarcoplasmic/endoplasmic reticulum calcium ATPase 1, tropomyosin alpha-1 chain, troponin isoforms, and alpha-actinin-3, showed significantly lower expression levels in the muscle of GSDV patients. These proteins could be potential biomarkers of the persistent muscle damage in the absence of prior exertion reported in GSDV patients. Further studies are needed to elucidate the molecular mechanisms by which PYGM controls the expression of these proteins.

Keywords:  GSDV; McArdle disease; PYGM; iTRAQ; metabolic myopathy; myophosphorylase; protein biomarkers; proteomics; skeletal muscle

DOI:  https://doi.org/10.3390/ijms23094650
FASEB J. 2022 May;36 Suppl 1

GAA Deficiency Disrupts Distal Airway Cells in Pompe Disease.

Léa El Haddad, Elias Lai, Preetish Murthy, Purushothama R Tata, Mai K ElMallah.

Pompe disease is an autosomal recessive glycogen storage disease caused by mutations in alpha-glucosidase (GAA) - an enzyme responsible of hydrolyzing lysosomal glycogen. GAA deficiency results in systemic lysosomal glycogen accumulation and cellular disruption. Skeletal muscle, motor neuron pathology and airway smooth muscle cells are known to contribute to respiratory insufficiency in Pompe disease, but the role of distal airway cells including alveolar type 1 and type 2 cells (AT1 and AT2, respectively) has not been evaluated. AT1 cells depend on lysosomes for cellular homeostasis to maintain a thin barrier for gas exchange whereas AT2 cells depend on lysosomal structures for surfactant production. Using an established mouse model of Pompe disease, the Gaa-/- mouse, we compared lung histology using Periodic acid-Schiff staining, quantification of immunohistochemistry staining and electron microscopy, and pulmonary mechanics using forced oscillometry FlexiVent system, between Gaa-/- and age-matched wild-type (WT) mice. We also perfomed single cell-RNA seq (scRNA-seq) on the distal airways of Gaa-/- mice. Lysosomal glycogen accumulation and engorged lamellar bodies were observed in the AT2 cells in Gaa-/- but not WT mice. Furthermore, AT2 positive surfactant protein-C (SPC) staining and lysosomal positive lysosomal associated membrane protein 1 (LAMP1) staining is more evident with increased colocalization of LAMP1 with the type 2 cell marker after quantification of each marker in Gaa-/- airway cells. The Gaa-/- mice exhibited a significant decrease in total and central airway resistance (Rrs and Rn, respectively), as well as a significant increase in lung compliance (Crs) versus WT mice. Moreover, in the dimensionless and volume-independent shape constant k that describes the curvature of the upper portion of the deflation limb of the Pressure-Volume curves, a statistically significant change was observed in Gaa-/- mice. This indicates a change in the intrinsic elastic properties of the respiratory system in Pompe disease. Finally, a robust transcriptomic dysregulation in AT1 and AT2 cells was detected scRNA-seq in Gaa-/- mice relative to WT mice. We conclude that GAA enzyme deficiency leads to glycogen accumulation in the distal airway stem cells that may contribute to respiratory impairments in Pompe disease. Our findings will inform the clinical care of patients with Pompe disease and will provide essential information for the development of novel therapies in Pompe disease that will address this airway pathology.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.L7829
Cardiovasc Hematol Agents Med Chem. 2022 May 10.

Effect of Pulicaria mauritanica on Glucose Metabolism and glycogen Content in Streptozotocin-Induced Diabetic Rats.

Amine Azzane, Ayoub Amssayef, Ahmed El-Haidani, Mohamed Eddouks.

   AIMS: The study aimed to assess the antihyperglycemic activity of Pulicaria mauritanica.
BACKGROUND: Pulicaria mauritanica is a medicinal and aromatic plant used for the treatment of many diseases such as inflammation, diabetes, and intestinal disorders.
OBJECTIVE: The main goals of this present paper were to confirm the antihyperglycemic capacity of aqueous extract from Pulicaria mauritanica in normoglycemic and diabetic rats over a period of time (7 days of treatment).
METHODS: The effect of the aqueous extract of Pulicaria mauritanica from aerial parts (AEPM) on glucose and lipid metabolism was tested using an acute test (single dose during 6 hours) and sub-chronic assay (repeated oral administration for seven days) at a dose of 60 mg/kg, the serum glucose levels were measured in normoglycemic and streptozotocin(STZ)-induced diabetic rats. In addition, the glycogen content in the liver, extensor digitorum longus (EDL), and soleus was evaluated. The antioxidant activity, phytochemical screening, and quantification of some secondary metabolites of this extract were also performed.
RESULTS: AEPM at a dose of 60 mg/kg reduced the plasma glucose concentrations significantly in STZ-induced diabetic rats after a single oral administration (p<0.05), this lowering effect became more significant during the repeated oral administration in hyperglycemic rats (p<0.0001). Also, the findings showed that this plant exhibited a significant increase in liver and skeletal soleus muscle glycogen content in diabetic rats. AEPM revealed a remarkable antioxidant activity in addition to the presence of polyphenol compounds such as flavonoids, tannins, saponins, sterols, glucides, terpenoids, quinones, anthraquinones, and mucilage.
CONCLUSION: The study shows that AEPM exhibits antihyperglycemic activity in diabetic rats and it increases liver and muscle glycogen content.

Keywords:  Antihyperglycemic; Pulicaria mauritanica; aqueous extract.; glycogen content; medicinal plant; streptozotocin

DOI:  https://doi.org/10.2174/1871525720666220510204624
FASEB J. 2022 May;36 Suppl 1

Mass Spectrometry Imaging Reveals Distinct Differences in Glycogen Accumulation in Lung Tumors from Appalachian Patients.

Michael Buoncristiani, Lindsey R Conroy, Harrison Clarke, Lyndsay E Young, Ramon C Sun.

Lung cancer is the leading cause of cancer related death in the United States, with patients from rural Appalachia having drastically higher incidence and mortality rates, driven by largely unknown mechanisms. Identifying molecular features that contribute to this health disparity is a critical step in lung cancer research that could lead to predictive biomarkers and personalized therapy for the Appalachia population. Recently, aberrant glycogen accumulation in lung tumors has been reported to promote lung cancer progression. However, the full clinical implications of dysregulated glycogen metabolism and its role in lung cancer health disparities has yet to be explored. Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) is a new and innovative technique that combines mass spectrometry with high resolution imaging, enabling the detection of hundreds of analytes with spatial distribution. We recently developed an advanced method to analyze glycogen content in formalin-fixed paraffin-embedded tissues using MALDI-MSI. With this technique, we analyzed glycogen chain length and glycogen phosphate content from tissue microarrays containing over 100 lung cancer patient samples banked at the University of Kentucky. Our patient cohort included adenocarcinoma and squamous cell carcinoma patients from Appalachian and non-Appalachian counties, with diverse cytopathological features. We found significant glycogen accumulation and higher glycogen phosphate content in lung tumor tissue compared to match normal lung across all patients. Further, we found glycogen accumulation is markedly high in adenocarcinoma patients compared to other lung cancer subtypes. Interestingly, Appalachian adenocarcinoma patients exhibit increased glycogen accumulation and higher glycogen phosphate content than patients from non-Appalachian counties. These data suggest differential glycogen accumulation is a unique feature of lung tumors from Appalachian adenocarcinoma patients. Our study highlights the potential clinical applications of MALDI-MSI for digital pathology, biomarker applications, and reveals molecular features that contribute to the health disparity in Appalachian lung cancer patients that warrant further molecular analysis.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R2536
Physiol Rep. 2022 May;10(9): e15297

Combined effects of exercise training and D-allulose intake on endurance capacity in mice.

Takamasa Tsuzuki, Ryo Suzuki, Risa Kajun, Takako Yamada, Tetsuo Iida, Bingyang Liu, Teruhiko Koike, Yukiyasu Toyoda, Takayuki Negishi, Kazunori Yukawa.

  This study investigated the combined effects of exercise training and D-allulose intake on endurance capacity in mice. Male C57BL/6J mice were fed either a control diet (Con) or a 3% D-allulose diet (Allu) and further divided into the sedentary (Sed) or exercise training (Ex) groups (Con-Sed, Con-Ex, Allu-Sed, Allu-Ex, respectively; n = 6-7/group). The mice in the Ex groups were trained on a motor-driven treadmill 5 days/week for 4 weeks (15-18 m/min, 60 min). After the exercise training period, all mice underwent an exhaustive running test to assess their endurance capacity. At 48 h after the running test, the mice in the Ex groups were subjected to run at 18 m/min for 60 min again. Then the gastrocnemius muscle and liver were sampled immediately after the exercise bout. The running time until exhaustion tended to be higher in the Allu-Ex than in the Con-Ex group (p = 0.08). The muscle glycogen content was significantly lower in the Con-Ex than in the Con-Sed group and was significantly higher in the Allu-Ex than in the Con-Ex group (p < 0.05). Moreover, exercise training increased the phosphorylation levels of adenosine monophosphate-activated protein kinase (AMPK) in the muscle and liver. The phosphorylation levels of acetyl coenzyme A carboxylase (ACC), a downstream of AMPK, in the muscle and liver were significantly higher in the Allu-Ex than in the Con-Sed group (p < 0.05), suggesting that the combination of exercise training and D-allulose might have activated the AMPK-ACC signaling pathway, which is associated with fatty acid oxidation in the muscle and liver. Taken together, our data suggested the combination of exercise training and D-allulose intake as an effective strategy to upregulate endurance capacity in mice. This may be associated with sparing glycogen content and enhancing activation of AMPK-ACC signaling in the skeletal muscle.

Keywords:  endurance capacity; exercise training; glycogen; rare sugar

DOI:  https://doi.org/10.14814/phy2.15297
FASEB J. 2022 May;36 Suppl 1

Elucidating the Role of Glycogen in Glucose Transporter 1 Deficiency Syndrome.

Meredith Williams, Kia H Markussen, Madison Webb, Annette Mestas, Juan Pascual, Matthew S Gentry.

Glucose Transporter 1 Deficiency Syndrome (G1D) is a rare genetic disorder characterized by impaired brain glucose metabolism caused by mutations in the SLC2A1 gene. Mutations in the SLC2A1 gene lead to reduced or loss of function in the glucose transporter protein type 1 (GLUT-1), affecting its ability to deliver glucose across the blood brain barrier. This lack of glucose in the brain affects brain function and development, causing people with the disorder to suffer from seizures, learning disabilities, and struggle for independence. While decreased levels of glucose in G1D is recognized, glycogen levels in the brain have not been studied in human or animal models of the disease. We employed a mouse model of G1D syndrome characterized by a loss of function in the SLC2A1 gene to study glycogen levels. Wildtype and G1D animals of the same sex at 14 weeks old were utilized for this study. Immunohistochemical (IHC) staining with IV58B6 and an amyloglucosidase glycogen assay were used to determine regional and total glycogen levels, respectively. HALO software was employed to quantify IHC staining, and the enzymatic glycogen determination was measured with a spectrophotometric microplate reader. Through these techniques, it was determined that G1D mice had perturbed glycogen levels present in multiple regions of the brain. These data suggest that the G1D phenotype could be affected by perturbed levels of glycogen in the brain. Further research into the effect of glycogen levels in G1D may be important for determining disease modalities, defining disease progression, and understanding preclinical data and drug treatment.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.0R303
Eur J Med Genet. 2022 May 09. pii: S1769-7212(22)00099-4. [Epub ahead of print] 104518

Glycogen Storage Disease type IA refractory to cornstarch: Can next generation sequencing offer a solution?

Or Steg Saban, Ben Pode-Shakked, Bassam Abu-Libdeh, Maya Granot, Galia Barkai, Yael Haberman, Inon Roterman, Avishay Lahad, Dror S Shouval, Batia Weiss, Dina Marek-Yagel, Ortal Barel, Nurit Loberman-Nachum, Smadar Abraham, Raz Somech, David A Weinstein, Yair Anikster.

  Avoidance of fasting and regular ingestion of uncooked-cornstarch have long been the mainstay dietary treatment of Glycogen Storage Disease type Ia (GSD-Ia). However, GSD-Ia patients who despite optimal dietary treatment show poor glycemic control and are intolerant to cornstarch, present a complex clinical challenge. We pursued Whole Exome Sequencing (WES) in three such unrelated patients, to both confirm a molecular diagnosis of GSD-Ia, and seek additional variants in other genes (e.g. genes associated with amylase production) which may explain their persistent symptoms. WES confirmed the GSD-Ia diagnosis, with all three probands harboring the homozygous p.R83C variant in G6PC. While no other significant variants were identified for patients A and B, a homozygous p.G276V variant in the SI gene was detected in patient C, establishing the dual-diagnosis of GSD-Ia and Sucrase-Isomaltase Deficiency. To conclude, we suggest that WES should be considered in GSD-Ia patients who show persistent symptoms despite optimal dietary management.

Keywords:  Exome sequencing; Glycogen storage disease; Sucrase isomaltase deficiency; Uncooked cornstarch

DOI:  https://doi.org/10.1016/j.ejmg.2022.104518
Front Physiol. 2022 ;13 803126

Melatonin Potentiates Exercise-Induced Increases in Skeletal Muscle PGC-1α and Optimizes Glycogen Replenishment.

Vinícius Silva Faria, Fúlvia Barros Manchado-Gobatto, Pedro Paulo Menezes Scariot, Alessandro Moura Zagatto, Wladimir Rafael Beck.

  Compelling evidence has demonstrated the effect of melatonin on exhaustive exercise tolerance and its modulatory role in muscle energy substrates at the end of exercise. In line with this, PGC-1α and NRF-1 also seem to act on physical exercise tolerance and metabolic recovery after exercise. However, the literature still lacks reports on these proteins after exercise until exhaustion for animals treated with melatonin. Thus, the aim of the current study was to determine the effects of acute melatonin administration on muscle PGC-1α and NRF-1, and its modulatory role in glycogen and triglyceride contents in rats subjected to exhaustive swimming exercise at an intensity corresponding to the anaerobic lactacidemic threshold (iLAn). In a randomized controlled trial design, thirty-nine Wistar rats were allocated into four groups: control (CG = 10), rats treated with melatonin (MG = 9), rats submitted to exercise (EXG = 10), and rats treated with melatonin and submitted to exercise (MEXG = 10). Forty-eight hours after the graded exercise test, the animals received melatonin (10 mg/kg) or vehicles 30 min prior to time to exhaustion test in the iLAn (tlim). Three hours after tlim the animals were euthanized, followed by muscle collection for specific analyses: soleus muscles for immunofluorescence, gluteus maximus, red and white gastrocnemius for the assessment of glycogen and triglyceride contents, and liver for the measurement of glycogen content. Student t-test for independent samples, two-way ANOVA, and Newman keuls post hoc test were used. MEXG swam 120.3% more than animals treated with vehicle (EXG; p < 0.01). PGC-1α and NRF-1 were higher in MEXG with respect to the CG (p < 0.05); however, only PGC-1α was higher for MEXG when compared to EXG. Melatonin reduced the triglyceride content in gluteus maximus, red and white gastrocnemius (F = 6.66, F = 4.51, and F = 6.02, p < 0.05). The glycogen content in red gastrocnemius was higher in MEXG than in CG (p = 0.01), but not in EXG (p > 0.05). In conclusion, melatonin was found to enhance exercise tolerance, potentiate exercise-mediated increases in PGC-1α, decrease muscle triglyceride content and increase muscle glycogen 3 h after exhaustive exercise, rapidly providing a better cellular metabolic environment for future efforts.

Keywords:  N-acetyl-5-methoxytryptamine; aerobic exercise; energy metabolism (MeSH ID: D004734); ergogenic aid; nuclear respiratory factor 1 (NRF-1); peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α); recovery; skeletal muscle tissue

DOI:  https://doi.org/10.3389/fphys.2022.803126
FASEB J. 2022 May;36 Suppl 1

Hypoglossal Motoneuron (XII MN) Survival Over the Lifespan in Pompe Disease.

Brian E Barral, Michele L Singer, Sabhya Rana, Emmanuelle Lavassani, Megan K Pope, Barry J Byrne, David D Fuller.

Glycogen Storage Disease II, more commonly known as Pompe disease, is a lysosomal storage disease characterized by a partial or complete loss of acid α-glucosidase (GAA) activity. Lingual impairment and sleep disordered breathing are common symptoms of Pompe disease with a potential role of XII MN dysfunction in both cases. Through innervation of the tongue muscles, XII MNs contribute to swallowing, speech, and maintenance of upper airway patency. Studies of Pompe (Gaa-/-) mice have found molecular and histological markers of neurodegeneration, and a recent case study of a patient with late-onset Pompe disease revealed atrophied and possible degenerating XII MNs. However, whether the absence of GAA activity in Pompe disease directly leads to death of XII MNs is not definitively established. Because the preponderance of evidence indicates progressive neurodegeneration in Pompe disease, here we tested the hypothesis that when XII MNs do not express GAA activity, there will be a progressive loss of these cells over the lifespan. A novel transgenic mouse model (ChAT-cre+/+●Gaa+/-●eYFP+/+●Flox-Gaa+/+) was generated in which GAA activity is absent in ChAT positive neurons, which also carry a yellow fluorescent protein (YFP) marker. Thus MNs in this mouse model do not express GAA, but skeletal myofibers have normal GAA expression. Brainstem tissue was harvested in young (1-3 months of age) and advanced age mice (21-24 months). Tissues were cryosectioned at 20 μm increments across the entire XII motor nucleus. Sections were slide mounted and visualized under fluorescence microscopy to detect YFP. The XII motor nucleus was identified based on anatomical landmarks and MNs were identified based on location, size, morphology, and YFP fluorescence. Preliminary MN counts across the rostral-caudal extent of the XII nucleus (n=3 per group) indicate an approximately 7% decline in detectable YFP-positive XII MNs over the age span (young: 658±19; old 617±28). Further, the histological appearance of XII MNs showed striking differences between the two age groups. The MNs from older mice showed the prototypical hallmarks of neuronal lysosomal storage disease including a markedly enlarged soma and extensive vacuolization. These preliminary findings are consistent with the hypothesis that absence of GAA in XII MNs leads to a histopathological appearance and neurodegeneration. Ongoing studies are evaluating XII MNs in age matched wild type mice.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R3681
FASEB J. 2022 May;36 Suppl 1

Aberrant glycogen accumulation alters gene expression and promotes lung tumor progression in vivo.

Jessica F Lamb, Lindsey R Conroy, Alexis N James, Michael D Buoncristiani, Eric R Relich, Christine F Brainson, Ramon C Sun.

Lung cancer is one of the most prevalent cancers worldwide, accounting for nearly two million new cases each year. Lung adenocarcinoma (LUAD) is the most common subtype of lung cancer and is the leading cause of cancer related mortalities worldwide. LUAD has an extremely poor five-year survival rate, which is likely due to cases being diagnosed at advanced stages and thus being more difficult to treat the metastatic disease. Identifying the molecular processes that contribute to disease progression is a critical goal in lung cancer research that could lead to predictive biomarkers and novel therapies. Glycogen is the primary form of carbohydrate storage in mammalian cells, and its degradation product, Glucose 6-Phosphate (G6P) feeds directly into glycolysis, making glycogen intimately connected to central carbon metabolism. Recently, aberrant glycogen accumulation in lung tumors has been reported to promote lung cancer progression, driven by largely unknown mechanisms. We recently generated a transgenic KRASG12D /p53-/- LUAD mouse model that also lacks the glycogen phosphatase laforin (LKO). This model develops increased glycogen accumulation in the lungs and displays accelerated tumor growth compared to the KRASG12D /p53-/- control (WT), as measured by Ki67 staining. To identify potential biological processes perturbed by LUAD-glycogen, we performed RNA-sequencing on lung tumors resected from WT and LKO mice. We identified over 300 genes that are differentially expressed between WT and LKO lung tumors. Specifically, gene set enrichment analysis (GSEA) revealed genes that were up-regulated in LKO lung tumors were involved in extracellular matrix remodeling, cell-to-cell communication, and cell proliferation. All of these processes are implicated in tumor growth, which supports our initial observation that LKO mice have increased tumor burden and disease progression. Our findings ultimately highlight several potential mechanisms by which LUAD-glycogen promotes LUAD tumor progression, which can be further investigated to identify novel biomarkers and therapeutic targets.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R3959
FASEB J. 2022 May;36 Suppl 1

The Yeast Glycogen Synthase Kinase Homolog Rim11 Phosphorylates the Phosphatidic Acid Phosphatase Pah1 to Inhibit its Catalytic Activity.

Shoily P Khondker, Gil-Soo Han, George M Carman.

The yeast phosphatidic acid (PA) phosphatase, Pah1, regulates the synthesis of triacylglycerol (TAG) and phospholipids by controlling the relative amounts of its substrate PA and product diacylglycerol. Pah1 phosphorylation, which is mediated by multiple protein kinases, has been shown to protect the protein against proteasomal degradation and regulates its localization and catalytic activity. Phosphorylated Pah1 is cytoplasmic, but it translocates to the nuclear/endoplasmic reticulum membrane for catalytic function through its dephosphorylation. In this study, we show that Rim11, a yeast homolog of glycogen synthase kinase phosphorylates Pah1. The rim11Δ mutant shows alterations in lipid composition with elevated TAG levels during exponential growth, the phase in which Rim11 is the most abundant. Rim11 purified from yeast phosphorylated Escherichia coli-expressed Pah1, which lacks endogenous phosphorylation, in a manner that is dependent on reaction time and the amounts of Rim11, Pah1, and ATP. Phosphoamino acid analysis and phosphopeptide mapping showed that Pah1 phosphorylation by Rim11 occurs at multiple serine and threonine residues, which was supported by mass spectrometry analysis which indicated that Rim11 has a major phosphorylation site that is shared with multiple kinases (Ser-602) and two unique minor phosphorylation sites (Thr-163 and Thr-164). Furthermore, in vitro PA phosphatase assays show that Pah1 catalytic activity is inhibited following phosphorylation by Rim11.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R3079
Indian J Pathol Microbiol. 2022 May;65(Supplement): S277-S290

Approach to the diagnosis of metabolic myopathies.

Madhu Nagappa, Gayathri Narayanappa.

  Metabolic myopathies are a diverse group of genetic disorders that result in impaired energy production. They are individually rare and several have received the 'orphan disorder' status. However, collectively they constitute a relatively common group of disorders that affect not only the skeletal muscle but also the heart, liver, and brain among others. Mitochondrial disorders, with a frequency of 1/8000 population, are the commonest cause of metabolic myopathies. Three main groups that cause metabolic myopathy are glycogen storage disorders (GSD), fatty acid oxidation defects (FAOD), and mitochondrial myopathies. Clinically, patients present with varied ages at onset and neuromuscular features. While newborns and infants typically present with hypotonia and multisystem involvement chiefly affecting the liver, heart, kidney, and brain, patients with onset later in life present with exercise intolerance with or without progressive muscle weakness and myoglobinuria. In general, GSDs result in high-intensity exercise intolerance while, FAODs, and mitochondrial myopathies predominantly manifest during endurance-type activity, fasting, or metabolically stressful conditions. Evaluation of these patients comprises a meticulous clinical examination and a battery of investigations which includes- exercise stress testing, metabolic and biochemical screening, electrophysiological studies, neuro-imaging, muscle biopsy, and molecular genetics. Accurate and early detection of metabolic myopathies allows timely counseling to prevent metabolic crises and helps in therapeutic interventions. This review summarizes the clinical features, diagnostic tests, pathological features, treatment and presents an algorithm to diagnose these three main groups of disorders.

Keywords:  Glycogen storage disorders; lipid storage disorders; mitochondrial disorders

DOI:  https://doi.org/10.4103/ijpm.ijpm_1088_21
Tissue Cell. 2022 May 02. pii: S0040-8166(22)00085-4. [Epub ahead of print]76 101813

Upregulation of BRD7 protects podocytes against high glucose-induced apoptosis by enhancing Nrf2 in a GSK-3β-dependent manner.

Xiangyou Yu, Ning Jiang, Jing Li, Xiaofeng Li, Shenglin He.

  Bromodomain-containing protein 7 (BRD7) is linked to a variety of pathophysiological conditions. However, it is still unclear whether BRD7 is connected with diabetic nephropathy. This research explored the relevance of BRD7 in diabetic nephropathy using high glucose (HG)-stimulated podocytes in vitro. BRD7 expression in podocytes was decreased after HG stimulation. Podocytes with forced BRD7 expression were protected from HG-induced apoptosis, oxidative stress and inflammation. Further data revealed that forced expression of BRD7 led to enhanced nuclear factor erythroid-2-related factor 2 (Nrf2) activation in HG-stimulated podocytes, associated with the upregulation of glycogen synthase kinase-3β (GSK-3β) phosphorylation. Reactivation of GSK-3β diminished BRD7-elicited Nrf2 activation. In addition, restraining of Nrf2 diminished the BRD7 overexpression-induced beneficial effects on HG-induced podocyte damage. Taken together, these data document that BRD7 defends against HG-induced podocyte damage by enhancing Nrf2 via regulation of GSK-3β. Our work indicates that the BRD7/GSK-3β/Nrf2 axis may play a key role in mediating podocyte injury in diabetic nephropathy.

Keywords:  BRD7; Diabetic nephropathy; Inflammation; Nrf2; Oxidative stress

DOI:  https://doi.org/10.1016/j.tice.2022.101813
Mol Genet Genomic Med. 2022 May 09. e1957

Classic infantile-onset Pompe disease with histopathological neurologic findings linked to a novel GAA gene 4 bp deletion: A case study.

Magdalena Cerón-Rodríguez, Daniela Castillo-García, Carlos-Patricio Acosta-Rodríguez-Bueno, Jesús Aguirre-Hernández, Juan-Rafael Murillo-Eliosa, Pedro Valencia-Mayoral, Argelia Escobar-Sánchez, Juan-Luis Salgado-Loza.

  Pompe disease (PD) is an autosomal recessive disorder by a deficiency of acid α-glucosidase (GAA) with intralysosomal glycogen accumulation in multiple tissues. We present the case of a 5-month-old male with hypertrophic cardiomyopathy, hypotony, feeding difficulties, and oxygen requirement since birth. At 3 months of age, he develops heart failure, respiratory impairment, and neurological deterioration. The echocardiogram revealed concentric hypertrophic cardiomyopathy with left-diastolic dysfunction. We found increased creatine-phosphokinase, lactate dehydrogenase, and urinary glucose tetrasaccharide levels, 50% of PAS-positive vacuolated lymphocytes in the peripheral blood smear, and low GAA activity. Sequencing of coding exons and flanking intronic sequences revealed a novel homozygous 4 bp deletion in exon 15 of the GAA gene (c.2066_2069delAGCC/p.Glu689Glyfs*6). IOPD was diagnosed. At 5 months old, we started enzyme replacement therapy with an alpha-alglucosidase of 20 mg/kg weekly and immunomodulation with intravenous immunoglobulin. He developed two cardiorespiratory arrests with subsequent neurologic deterioration, convulsive crisis, and respiratory failure and died at 9 months old. We found the usual PD hallmarks in the heart, striated muscle, and liver but also we found neuronal lesions characterized by cytoplasm vacuolization with PAS-positive granules in the central nervous system and myenteric plexus. We describe a novel GAA gene pathogenic variant with a particular phenotype characterized by classic IOPD and neurologic histopathological findings. Enhancing the knowledge of lysosomal diseases is critical to improving the diagnosis and treatment of these patients.

Keywords:  GAA gene; acid alpha-glucosidase; c.2066_2069delAGCC; infantile-onset Pompe disease; neurologic; p.Glu689Glyfs*6

DOI:  https://doi.org/10.1002/mgg3.1957
FASEB J. 2022 May;36 Suppl 1

Multiple Freeze-thaw Cycles in Cope's Gray Treefrog Dryophytes chrysoscelis Reveal Novel Physiological, Biochemical, and Morphological Insights into Vertebrate Freeze Tolerance.

Elizabeth Evans, Matthew Wascher, David Goldstein, Carissa Krane.

The freeze tolerant anuran Dryophytes chrysoscelis, Cope's gray treefrog, mobilizes a complex cryoprotectant system that includes glycerol, glucose and urea to minimize damage induced by freezing and thawing of up to 65% of body water. It is hypothesized that, compared with a single freeze-thaw cycle, repeated freeze-thaw cycles in D. chrysoscelis will enhance cryoprotectant accumulation, glycogen depletion, and cryoinjury, while locomotor and morphological characteristics will be altered in association with a delay in thawing time. Wild-caught male treefrogs were cold acclimated prior to freezing. Animals were chilled to -2.5°C over 5 days, inoculated with ice to induce freezing, held frozen for 24 hrs, then thawed at 5°C for 24 hrs ("single freeze-thaw") or refrozen and thawed twice more over a period of 4 days ("repeated freeze-thaw") (n=4-6 per group). Cryoprotectant levels were measured in liver, muscle, and plasma. Glycogen was assayed in liver and muscle, and osmolality and hemoglobin (Hb; indicative of RBC hemolysis) in plasma. Body movements and skin color were documented by digital photography. Linear regression models of log-transformed data were used to test for multiplicative differences among groups and variable relationships. Glycerol, the most abundant cryoprotectant in all tissues measured in both thawed groups (single and repeated), increased 112-fold in single freeze-thaw animals and 185-fold in repeated freeze-thaw, compared with cold acclimated controls (P = 0.001). Glucose increased in both thawed groups in liver and plasma but not in muscle, whereas urea did not change. Liver glycogen decreased by ~50% and ~25% compared with controls in single and repeatedly thawed groups, respectively (P < 0.001). Osmolality increased ~2-fold in single and repeated freeze-thaw groups compared with controls (P < 0.001). A linear regression model using plasma glycerol alone can explain 65% of variation in plasma osmolality; the model is only marginally enhanced by the addition of plasma urea and is not enhanced by the addition of plasma glucose. Plasma Hb significantly increased in the repeated freeze-thaw group compared to the control (P < 0.05), indicating greater hemolysis with repeated freezing and thawing. Locomotor changes-the time for animals to lift their head, open their eyes, move a limb, and change overall body position-were significantly delayed in the second thaw compared with the first (P < 0.05). Skin color dynamically changes from blue to green to brown as frozen frogs thaw throughout all freeze-thaw cycles. Repeated freezing and thawing of vertebrates is almost entirely unstudied. Our results demonstrate cryoinjury (hemolysis) and delayed return of locomotor function after repeated freeze-thaw, despite progressive depletion of glycogen stores (a cryoprotectant source) and accumulation of glucose and glycerol and sustained levels of urea. Our ecologically relevant protocol, combined with an innovative and comprehensive analysis, provides novel insights into the complex and systemic nature of freeze tolerance in D. chrysoscelis.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R4116
Intern Med. 2022 May 07.

A Case of a Mild Clinical Phenotype with Myopathic and Hemolytic Forms of Phosphoglycerate Kinase Deficiency (PGK Osaka): A Case Report and Literature Review.

Kousuke Baba, Tokiko Fukuda, Mitsuru Furuta, Satoru Tada, Atsuko Imai, Yoshihiro Asano, Hideo Sugie, Masanori P Takahashi, Hideki Mochizuki.

  Phosphoglycerate kinase (PGK) deficiency is an X-linked disorder characterized by a combination of hemolytic anemia, myopathy, and brain involvement. We herein report a Japanese man who had several episodes of rhabdomyolysis but was training strenuously to be a professional boxer. Mild hemolytic anemia was noted. The enzymatic activity of PGK was significantly reduced, and a novel missense mutation, p.S62N, was identified in the PGK1 gene. A literature review revealed only one case with a mixed hemolytic and myopathic phenotype like ours. This mild phenotype indicates the complex pathophysiology of PGK deficiency and suggests the benefits of dietary control and exercise.

Keywords:  PGK Osaka; dietary intake; glycogen storage disease; hemolysis; ischemic exercise test; myopathy

DOI:  https://doi.org/10.2169/internalmedicine.9221-21
FASEB J. 2022 May;36 Suppl 1

Pharmacological Evaluation of Beta-Hydroxifosphocarnitine in No-Alcoholic Esteatohepatitis Induced in Rats.

Janet Sanchez-Quevedo, Jorge Luis Rosado, Lourdes Rodriguez-Fragoso.

AIM: Evaluate the pharmacological effect of Β-Hydroxyphosphocarnitine (β-HFC) on non-alcoholic steatohepatitis induced in rats.
INTRODUCTION: Nonalcoholic steatotepatitis (NASH) is a serious global public health problem, it is related to other pathologies with increasing prevalence, manifested in the increased prevalence of NASH. Type 2 diabetes mellitus and obesity are the main pathologies related to NASH. There is no specific drug for NASH, the current drugs used for NASH are related to serious side effects, which is why there is an urgent need in the development of an effective therapy for NASH but with fewer side effects. L-carnitine has an effect on improving metabolic alterations related to NASH, however, its intestinal absorption is limited. B-HFC is an analog of L-carnitine that has been shown to be safe for administration, to maintain pharmacological properties of its precursor and its absorption is greater than that of L-carnitine. So it can be a good treatment for NASH.
METHOD: The NASH model was developed in male Wistar rats by ingesting carbonated drink as a source of fructose, coconut oil and carbon tetrachloride. 3 groups were formed with NASH (n = 8); NASH, NASH -β-HFC and NASH-pioglitazone. Another 3 groups of healthy rats (n = 8); control, control-β-HFC and control-pioglitazone. The effect of β-HFC in rats with NASH was evaluated by staining of histological sections of liver. The stains used were Masson's trichrome, hematoxylin and osin and Periodic Acid-Schiff (PAS). Biochemical analysis was performed to evaluate the effect of β-HFC on the metabolic alterations that characterize NASH.
RESULT: It was previously reported that β-HFC reduced the triglyceride levels of rats with NASH, as well as the levels of liver enzymes. Evidencing the effect of β-HFC in improving lipid metabolism, manifesting itself in less liver damage. For this occasion we will report the effect of β-HFC on liver glycogen levels. Glycogen is a reserve of the cell, as a source of glucose in prolonged fasting states. Our results demonstrated a higher glycogen reserve in the NASH rats. This result was expected, since the rats had a high fructose intake. It is important to mention that the rats with NASH but treated with β-HFC presented reduced glycogen levels, this effect can be attributed to a more efficient β-oxidation process, which could also justify the reduction of triglycerides and fibrosis. Therefore, we could argue that a longer treatment time, the liver alterations in NASH would improve significantly.
CONCLUSION: β-HFC has an effect on improving liver and metabolic alterations characteristic of the development of NASH.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R2721
J Agric Food Chem. 2022 May 12.

Effect of Starch Primers on the Fine Structure of Enzymatically Synthesized Glycogen-like Glucan.

Jialin Liu, Yanli Wang, Xiaoxiao Li, Zhengyu Jin, Birte Svensson, Yuxiang Bai.

  Glycogen-like glucan (GnG) is a unique hyperbranched polysaccharide nanoparticle which is drawing increasing attention due to its biodegradability and abundant short branches that can be functionalized. Because starch and GnG are both composed of glucose residues and have similar glucosidic bonds, GnG could be fabricated by sucrose phosphorylase, α-glucan phosphorylase, and branching enzymes from starch primers and sucrose. In this study, high-amylose starch, normal starch, and waxy corn starch were used as primers to synthesize GnG, and their impact on the fine structure of GnG was investigated. Structural analysis indicated that with increasing content of amylopectin in the starch primer, the proportion of short chains in GnG decreased, and the degree of β-amylolysis and α-amylolysis was enhanced. Amylose in the primer contributed to a compact and homogeneous structure of GnG, while amylopectin triggered the formation of branch points with a more open distribution. These findings provide a new strategy for regulating the fine structure of GnG.

Keywords:  amylopectin; amylose; branching pattern; corn starch; enzymatic synthesis; glycogen

DOI:  https://doi.org/10.1021/acs.jafc.2c00152
FASEB J. 2022 May;36 Suppl 1

Electrical Stimulated Glut4 Trafficking Reduces Critical Illness-Associated Muscle Wasting.

Alex B Addinsall, Nicola Cacciani, Anders Backéus, Yvette Hedstöm, Lars Larsson.

Critical illness myopathy (CIM) is a debilitating condition characterized by the preferential loss of the motor protein myosin. CIM is a consequence of critical care, impairs recovery and provides long-term complications, and mortality. CIM pathophysiology is complex and remains incompletely understood, however loss of mechanical stimuli appears central to critical illness associated muscle atrophy and weakness. Passive mechanical loading (ML) and electrical stimulation (ES) augment muscle mass and function, however the mechanisms underpinning these therapies are less known. Here we aimed to assess the hypothesis that chronic supramaximal ES would ameliorate CIM in a unique experimental rat model of critical care. Rats were subjected to deep sedation, controlled mechanical ventilation, and immobilization with and without direct soleus ES for 8 days. Critical care reduced soleus muscle mass, cross-sectional area (CSA), Myosin: Actin ratio and single muscle fibre specific force. ES reduced the loss of soleus muscle fibre CSA and Myosin: Actin ratio yet failed to effect specific force. Insulin signalling gene pathway was downregulated following critical care and GLUT4 trafficking was reduced leading to muscle glycogen depletion. ES promoted phosphofructokinase and insulin signalling pathways and maintained GLUT4 translocation and glycogen levels. ES evoked AMPK, but not AKT, signalling pathway, where the downstream target TBC1D4 and AMPK-specific P-TBC1D4 levels tended to be increased. Reduced muscle protein degradation promoted soleus CSA, as ES reduced E3 ligases Atrogin-1 and MuRF1 downstream of AMPK-FoxO3. These results demonstrate chronic supramaximal ES reduces critical care associated muscle wasting, preserved glucose signalling and reduced muscle protein degradation in CIM.

DOI: https://doi.org/10.1096/fasebj.2022.36.S1.R3369
Int Immunopharmacol. 2022 May 09. pii: S1567-5769(22)00284-3. [Epub ahead of print]109 108800

Sevoflurane suppresses NLRP3 inflammasome-mediated pyroptotic cell death to attenuate lipopolysaccharide-induced acute lung injury through inducing GSK-3β phosphorylation and activation.

Fushuang Zheng, Xiuying Wu, Jin Zhang, Zhiling Fu.

  Pyroptosis is a type of programmed cell death, and pyroptosis-associated inflammatory response is closely associated with the pathogenesis of acute lung injury (ALI). Sevoflurane, a common clinical anesthetic, has been reported as therapeutic drug for ALI. However, the detailed mechanisms by which sevoflurane ameliorates ALI have not been fully delineated. In this study, we found that sevoflurane phosphorylated and activated the GSK-3β to suppress LPS-induced pyroptotic cell death, inflammation and ALI. Specifically, in the LPS-induced ALI mice models, sevoflurane attenuated lung damages and fibrosis, and restrained the production of the pro-inflammatory cytokines. Also, LPS increased the expression levels of pyroptosis-related proteins to promote pyroptotic cell death in ALI mice lung tissues, and LPS-induced pyroptotic cell death was reduced by sevoflurane co-treatment. Moreover, the potential underlying mechanisms were uncovered, and we illustrated that sevoflurane promoted GSK-3β activation in LPS-treated ALI mice lung tissues, and re-activation of GSK-3β by the PI3K/Akt pathway inhibitor LY294002 suppressed LPS-induced pyroptotic cell death in vivo. Consistently, in the in vitro macrophages, our data hinted that LPS-induced pyroptotic cell death were also reversed by sevoflurane. Collectively, the above results suggest that sevoflurane re-activated GSK-3β to suppress LPS-induced pyroptotic cell death, inflammation and ALI.

Keywords:  Acute lung injury; GSK-3β; NLRP3; Pyroptotic cell death; Sevoflurane

DOI:  https://doi.org/10.1016/j.intimp.2022.108800