bims-glecem 2023-06-11 papers

bims-glecem

Biomed News

on Glycogen metabolism in exercise, cancer and energy metabolism

Issue of 2023–06–11
twelve papers selected by
Dipsikha Biswas, Københavns Universitet

Platelet glycogenolysis is important for energy production and function.
Liver transplantation in glycogen storage disease type Ib: The role of SGLT2 inhibitors.
Clinical and Functional Characterization of Novel AGL Variants in Two Families with Glycogen Storage Disease Type III.
A case of glycogen storage disease type Ⅰa with gout as the first manifestation.
Multidisciplinary docking, kinetics and X-ray crystallography studies of baicalein acting as a glycogen phosphorylase inhibitor and determination of its' potential against glioblastoma in cellular models.
Mitochondrial reprogramming in peripheral blood mononuclear cells of patients with glycogen storage disease type Ia.
Bedtime extended release cornstarch improves biochemical profile and sleep quality for patients with glycogen storage disease type Ia.
Glycogen synthase 1 targeting reveals a metabolic vulnerability in triple-negative breast cancer.
Molecular structure and characteristics of phytoglycogen, glycogen and amylopectin subjected to mild acid hydrolysis.
Manipulation of glycogen and sucrose synthesis increases photosynthetic productivity in cyanobacteria.
AS160 expression, but not AS160 Serine-588, Threonine-642, and Serine-704 phosphorylation, is essential for elevated insulin-stimulated glucose uptake by skeletal muscle from female rats after acute exercise.
Label-Free Evaluation of Maturation and Hepatotoxicity of Human iPSC-Derived Hepatocytes Using Hyperspectral Raman Imaging.

Platelets. 2023 Dec;34(1): 2222184

Platelet glycogenolysis is important for energy production and function.

Kanakanagavalli Shravani Prakhya, Hemendra Vekaria, Daniёlle M Coenen, Linda Omali, Joshua Lykins, Smita Joshi, Hammodah R Alfar, Qing Jun Wang, Patrick Sullivan, Sidney W Whiteheart.

  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.

Keywords:  Bioenergetics; glycogen; metabolism; platelets

DOI:  https://doi.org/10.1080/09537104.2023.2222184
Mol Genet Metab Rep. 2023 Jun;35 100977

Liver transplantation in glycogen storage disease type Ib: The role of SGLT2 inhibitors.

Simona Murko, Manuela Peschka, Konstantinos Tsiakas, Sebastian Schulz-Jürgensen, Uta Herden, René Santer.

  We report on liver transplantation in two patients with GSD Ib on treatment with empagliflozin. The use of this SGLT2 inhibitor resulted in a marked decrease of 1,5-anhydroglucitol which has an important role in the development of neutropenia in this condition. As intended, this caused a significant rise of neutrophil numbers. Liver transplantation alone did not produce the desired effect and our observation argues for continuing SGLT2 inhibitor treatment after transplantation.

Keywords:  Empagliflozin; GSD1b; Glycogen storage disease Ib; Liver transplantation; SGLT2 inhibitor

DOI:  https://doi.org/10.1016/j.ymgmr.2023.100977
Int J Endocrinol. 2023 ;2023 6679871

Clinical and Functional Characterization of Novel AGL Variants in Two Families with Glycogen Storage Disease Type III.

Tingting Yu, Hao Fu, Aoyu Yang, Yan Liang.

Purpose: Glycogen storage disease type III (GSDIII) is a uncommon autosomal recessive inherited metabolic disorder, which is caused by variants in the AGL gene. The purpose of this study was to elucidate the clinical and functional features of two novel variants in two families with GSDIIIa.
Methods: We collected the clinical and laboratory data of the two patients. Genetic testing was performed using GSDs gene panel sequencing, and the identified variants were classified according to the American College of Medical Genetics (ACMG) criteria. The pathogenicity of the novel variants was furthermore assessed through bioinformatics analysis and cellular functional validation experiments.
Results: The two patients were hospitalized with abnormal liver function or hepatomegaly, which was characterized by remarkably elevated liver enzyme and muscle enzyme levels, as well as hepatomegaly, and were eventually diagnosed with GSDIIIa. Genetic analysis detected two novel variants of AGL gene in the two patients: c.1484A > G (p.Y495C), c.1981G > T (p.D661Y). Bioinformatics analysis indicated that the two novel missense mutations most likely altered the protein's conformation and therefore made the enzyme it encodes less active. Based on the ACMG criteria, both variants were considered likely pathogenic, in accordance with the functional analysis results, which demonstrated that the mutated protein was still localized in the cytoplasm and that the glycogen content of cells transfected with the mutated AGL was increased compared to cells transfected with the wild-type one.
Conclusion: These findings indicated that the two newly identified variants in the AGL gene (c.1484A > G; c.1981G > T) were undoubtedly pathogenic mutations, inducing a slight reduction in glycogen debranching enzyme activity and a mild increase in intracellular glycogen content. Two patients who visited us with abnormal liver function, or hepatomegaly, improved dramatically after treatment with oral uncooked cornstarch, but the effects on skeletal muscle and myocardium required further observation.

DOI: https://doi.org/10.1155/2023/6679871
Zhejiang Da Xue Xue Bao Yi Xue Ban. 2023 Apr 25. pii: 1008-9292(2023)02-0230-07. [Epub ahead of print]52(2): 230-236

A case of glycogen storage disease type Ⅰa with gout as the first manifestation.

Lingying Dan, Xiaoxiao Song, Hanxiao Yu.

  A 24-year-old male was admitted due to recurrent redness, swelling, fever and pain in the ankle, frequently accompanied by hungry feeling. Dual energy CT scans showed multiple small gouty stones in the posterior edge of the bilateral calcaneus and in the space between the bilateral metatarsophalangeal joints. The laboratory examination results indicated hyperlipidemia, high lactate lipids, and low fasting blood glucose. Histopathology of liver biopsy showed significant glycogen accumulation. The results of gene sequencing revealed the compound heterozygous mutations of the G6PC gene c.248G>A (p.Arg83His) and c.238T>A (p.Phe80Ile) in the proband. The c.248G>A mutation was from mother and the c.238T>A mutation was from father. The diagnosis of glycogen storage disease type Ⅰa was confirmed. After giving a high starch diet and limiting monosaccharide intake, as well as receiving uric acid and blood lipids lowering therapy, the condition of the patient was gradually stabilized. After a one-year follow-up, there were no acute episodes of gout and a significant improvement in hungry feeling in the patient.

Keywords:  Case report; Gene mutation; Glucose-6-phosphatase catalytic subunit; Glycogen storage disease type Ⅰa; Gout

DOI:  https://doi.org/10.3724/zdxbyxb-2022-0530
Chem Biol Interact. 2023 Jun 03. pii: S0009-2797(23)00235-1. [Epub ahead of print] 110568

Multidisciplinary docking, kinetics and X-ray crystallography studies of baicalein acting as a glycogen phosphorylase inhibitor and determination of its' potential against glioblastoma in cellular models.

Rachel T Mathomes, Symeon M Koulas, Ioannis Tsialtas, George Stravodimos, Philip J Welsby, Anna-Maria G Psarra, Izabela Stasik, Demetres D Leonidas, Joseph M Hayes.

Glycogen phosphorylase (GP) is the rate-determining enzyme in the glycogenolysis pathway. Glioblastoma (GBM) is amongst the most aggressive cancers of the central nervous system. The role of GP and glycogen metabolism in the context of cancer cell metabolic reprogramming is recognised, so that GP inhibitors may have potential treatment benefits. Here, baicalein (5,6,7-trihydroxyflavone) is studied as a GP inhibitor, and for its effects on glycogenolysis and glioblastoma at the cellular level. The compound is revealed as a potent GP inhibitor against human brain GPa (Ki = 32.54 μM), human liver GPa (Ki = 8.77 μM) and rabbit muscle GPb (Ki = 5.66 μM) isoforms. It is also an effective inhibitor of glycogenolysis (IC50 = 119.6 μM), measured in HepG2 cells. Most significantly, baicalein demonstrated anti-cancer potential through concentration- and time-dependent decrease in cell viability for three GBM cell-lines (U-251 MG, U-87 MG, T98-G) with IC50 values of ∼20-55 μM (48- and 72-h). Its effectiveness against T98-G suggests potential against GBM with resistance to temozolomide (the first-line therapy) due to a positive O6-methylguanine-DNA methyltransferase (MGMT) status. The solved X-ray structure of rabbit muscle GP-baicalein complex will facilitate structure-based design of GP inhibitors. Further exploration of baicalein and other GP inhibitors with different isoform specificities against glioblastoma is suggested.

DOI: https://doi.org/10.1016/j.cbi.2023.110568
Genes Nutr. 2023 Jun 06. 18(1): 10

Mitochondrial reprogramming in peripheral blood mononuclear cells of patients with glycogen storage disease type Ia.

Alessandro Rossi, Antonia Assunto, Carmen Rosano, Sara Tucci, Margherita Ruoppolo, Marianna Caterino, Francesca Pirozzi, Pietro Strisciuglio, Giancarlo Parenti, Daniela Melis.

   BACKGROUND: Glycogen storage disease type Ia (GSDIa) is an inborn metabolic disorder caused by the deficiency of glucose-6-phospatase-α (G6Pase-α) leading to mitochondrial dysfunction. It remains unclear whether mitochondrial dysfunction is present in patients' peripheral blood mononuclear cells (PBMC) and whether dietary treatment can play a role. The aim of this study was to investigate mitochondrial function in PBMC of GSDIa patients.
METHODS: Ten GSDIa patients and 10 age-, sex- and fasting-time matched controls were enrolled. Expression of genes involved in mitochondrial function and activity of key fatty acid oxidation (FAO) and Krebs cycle proteins were assessed in PBMC. Targeted metabolomics and assessment of metabolic control markers were also performed.
RESULTS: Adult GSDIa patients showed increased CPT1A, SDHB, TFAM, mTOR expression (p < 0.05) and increased VLCAD, CPT2 and citrate synthase activity in PBMC (p < 0.05). VLCAD activity directly correlated with WC (p < 0.01), BMI (p < 0.05), serum malonycarnitine levels (p < 0.05). CPT2 activity directly correlated with BMI (p < 0.05).
CONCLUSION: Mitochondrial reprogramming is detectable in PBMC of GSDIa patients. This feature may develop as an adaptation to the liver enzyme defect and may be triggered by dietary (over)treatment in the frame of G6Pase-α deficiency. PBMC can represent an adequate mean to assess (diet-induced) metabolic disturbances in GSDIa.

Keywords:  Biomarker; CPT1; Diet; Fatty acid oxidation; Glycogen storage disease; Monitoring

DOI:  https://doi.org/10.1186/s12263-023-00729-y
Mol Genet Genomic Med. 2023 Jun 05. e2221

Bedtime extended release cornstarch improves biochemical profile and sleep quality for patients with glycogen storage disease type Ia.

Rai-Hseng Hsu, Hui-An Chen, Yin-Hsiu Chien, Wuh-Liang Hwu, Ju-Li Lin, Hui-Ling Weng, Yi-Ting Lin, Yu-Ching Lin, Ni-Chung Lee.

   BACKGROUND: Patients with glycogen storage disease type Ia (GSDIa) are prone to hypoglycemia. Uncooked cornstarch (CS) is the treatment, but maintaining nighttime blood glucose levels is still difficult.
METHODS: The study enrolled patients with GSDIa to investigate the benefits of bedtime extended release CS (ER-CS, Glycosade®) versus regular CS. The daytime CS schedule was not altered. A 7-day continuous glucose monitoring (CGM) was performed at the baseline and 12 weeks after using ER-CS. Biochemical profile, sleep quality (Pittsburgh Sleep Quality Index, PSQI), and quality of life (SF-36 questionnaire) were measured at the baseline and 24 weeks after using ER-CS.
RESULTS: Nine patients (9 to 33 years of age) were enrolled. Compared with the baseline (80.0 ± 6.33 mg/dL), the 12-week evaluations revealed higher mean morning glucose levels (86.5 ± 8.26 mg/dL, p = 0.015). Twenty-four weeks after the use of bedtime ER-CS, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels both decreased (from 69.3 ± 77.8 to 41.1 ± 40.4 U/L and from 78.8 ± 99.6 to 37.8 ± 28.81 U/L, respectively, p = 0.013 for both analyses), and sleep and fasting time both elongated (from 7.8 ± 0.87 to 8.6 ± 1.02 h and from 6.5 ± 1.22 to 7.6 ± 1.02 h, respectively, p = 0.011 for both analyses). The mean PSQI score in the five adult patients decreased significantly (from 5.8 ± 1.29 to 3.0 ± 1.71, p = 0.042).
CONCLUSION: This study provides evidence of clinically meaningful improvements by shifting only bedtime regular CS to ER-CS in patients with GSDIa. As ER-CS is considerably more expensive than regular CS, this approach presents a cost-effective alternative.

Keywords:  Pittsburgh sleep quality index (PSQI); continuous glucose monitoring (CGM); extended release cornstarch (ER-CS); glycogen storage disease type Ia (GSDIa)

DOI:  https://doi.org/10.1002/mgg3.2221
J Exp Clin Cancer Res. 2023 Jun 06. 42(1): 143

Glycogen synthase 1 targeting reveals a metabolic vulnerability in triple-negative breast cancer.

E C de Heer, C E Zois, E Bridges, B van der Vegt, H Sheldon, W A Veldman, M C Zwager, T van der Sluis, S Haider, T Morita, O Baba, C P Schröder, S de Jong, A L Harris, M Jalving.

   BACKGROUND: Hypoxia-induced glycogen turnover is implicated in cancer proliferation and therapy resistance. Triple-negative breast cancers (TNBCs), characterized by a hypoxic tumor microenvironment, respond poorly to therapy. We studied the expression of glycogen synthase 1 (GYS1), the key regulator of glycogenesis, and other glycogen-related enzymes in primary tumors of patients with breast cancer and evaluated the impact of GYS1 downregulation in preclinical models.
METHODS: mRNA expression of GYS1 and other glycogen-related enzymes in primary breast tumors and the correlation with patient survival were studied in the METABRIC dataset (n = 1904). Immunohistochemical staining of GYS1 and glycogen was performed on a tissue microarray of primary breast cancers (n = 337). In four breast cancer cell lines and a mouse xenograft model of triple-negative breast cancer, GYS1 was downregulated using small-interfering or stably expressed short-hairpin RNAs to study the effect of downregulation on breast cancer cell proliferation, glycogen content and sensitivity to various metabolically targeted drugs.
RESULTS: High GYS1 mRNA expression was associated with poor patient overall survival (HR 1.20, P = 0.009), especially in the TNBC subgroup (HR 1.52, P = 0.014). Immunohistochemical GYS1 expression in primary breast tumors was highest in TNBCs (median H-score 80, IQR 53-121) and other Ki67-high tumors (median H-score 85, IQR 57-124) (P < 0.0001). Knockdown of GYS1 impaired proliferation of breast cancer cells, depleted glycogen stores and delayed growth of MDA-MB-231 xenografts. Knockdown of GYS1 made breast cancer cells more vulnerable to inhibition of mitochondrial proteostasis.
CONCLUSIONS: Our findings highlight GYS1 as potential therapeutic target in breast cancer, especially in TNBC and other highly proliferative subsets.

Keywords:  Breast cancer; Glycogen; Glycogen synthase 1; Ki67; Mitochondria

DOI:  https://doi.org/10.1186/s13046-023-02715-z
NPJ Sci Food. 2023 Jun 08. 7(1): 27

Molecular structure and characteristics of phytoglycogen, glycogen and amylopectin subjected to mild acid hydrolysis.

Bo Pan, Ningjing Zhao, Qiuqi Xie, Yungao Li, Bruce R Hamaker, Ming Miao.

The structure and properties of phytoglycogen and glycogen subjected to acid hydrolysis was investigated using amylopectin as a reference. The degradation took place in two stages and the degree of hydrolysis was in the following order: amylopectin > phytoglycogen > glycogen. Upon acid hydrolysis, the molar mass distribution of phytoglycogen or glycogen gradually shifted to the smaller and broadening distribution region, whereas the distribution of amyopectin changed from bimodal to monomodal shape. The kinetic rate constant for depolymerization of phytoglycogen, amylopectin, and glycogen were 3.45 × 10-5/s, 6.13 × 10-5/s, and 0.96 × 10-5/s, respectively. The acid-treated sample had the smaller particle radius, lower percentage of α-1,6 linkage as well as higher rapidly digestible starch fractions. The depolymerization models were built to interpret the structural differences of glucose polymer during acid treatment, which would provide guideline to improve the structure understanding and precise application of branched glucan with desired properties.

DOI: https://doi.org/10.1038/s41538-023-00201-6
Front Microbiol. 2023 ;14 1124274

Manipulation of glycogen and sucrose synthesis increases photosynthetic productivity in cyanobacteria.

Michael Cantrell, Melissa Cano, Jacob Sebesta, Troy Paddock, Wei Xiong, Katherine J Chou, Jianping Yu.

  Photosynthetic productivity is limited by low energy conversion efficiency in naturally evolved photosynthetic organisms, via multiple mechanisms that are not fully understood. Here we show evidence that extends recent findings that cyanobacteria use "futile" cycles in the synthesis and degradation of carbon compounds to dissipate ATP. Reduction of the glycogen cycle or the sucrose cycle in the model cyanobacterium Synechocystis 6803 led to redirection of cellular energy toward faster growth under simulated outdoor light conditions in photobioreactors that was accompanied by higher energy charge [concentration ratio of ATP/(ATP + ADP)]. Such manipulation of energy metabolism may have potential in engineering microalgal chassis cells to increase productivity of biomass or target metabolites.

Keywords:  ATP; cyanobacteria; glycogen; photosynthesis; sucrose

DOI:  https://doi.org/10.3389/fmicb.2023.1124274
FASEB J. 2023 Jul;37(7): e23021

AS160 expression, but not AS160 Serine-588, Threonine-642, and Serine-704 phosphorylation, is essential for elevated insulin-stimulated glucose uptake by skeletal muscle from female rats after acute exercise.

Haiyan Wang, Amy Zheng, Edward B Arias, Seong Eun Kwak, Xiufang Pan, Dongsheng Duan, Gregory D Cartee.

  One exercise session can increase subsequent insulin-stimulated glucose uptake (ISGU) by skeletal muscle in both sexes. We recently found that muscle expression and phosphorylation of key sites of Akt substrate of 160 kDa (AS160; also called TBC1D4) are essential for the full-exercise effect on postexercise-ISGU (PEX-ISGU) in male rats. In striking contrast, AS160's role in increased PEX-ISGU has not been rigorously tested in females. Our rationale was to address this major knowledge gap. Wild-type (WT) and AS160-knockout (KO) rats were either sedentary or acutely exercised. Adeno-associated virus (AAV) vectors were engineered to express either WT-AS160 or AS160 mutated on key serine and threonine residues (Ser588, Thr642, and Ser704) to alanine to prevent their phosphorylation. AAV vectors were delivered to the muscle of AS160-KO rats to determine if WT-AS160 or phosphorylation-inactivated AS160 would influence PEX-ISGU. AS160-KO rats have lower skeletal muscle abundance of the GLUT4 glucose transporter protein. This GLUT4 deficit was rescued using AAV delivery of GLUT4 to determine if eliminating muscle GLUT4 deficiency would normalize PEX-ISGU. The novel results were as follows: (1) AS160 expression was required for greater PEX-ISGU; (2) rescuing muscle AS160 expression in AS160-KO rats restored elevated PEX-ISGU; (3) AS160's essential role for the postexercise increase in ISGU was not attributable to reduced muscle GLUT4 content; and (4) AS160 phosphorylation on Ser588, Thr642, and Ser704 was not essential for greater PEX-ISGU. In conclusion, these novel findings revealed that three phosphosites widely proposed to influence PEX-ISGU are not required for this important outcome in female rats.

Keywords:  AMP-activated protein kinase; GLUT4 glucose transporter; acute exercise; female; glucose transport; glycogen; insulin resistance; insulin signaling; sexual dimorphism

DOI:  https://doi.org/10.1096/fj.202300282RR
Anal Chem. 2023 Jun 09.

Label-Free Evaluation of Maturation and Hepatotoxicity of Human iPSC-Derived Hepatocytes Using Hyperspectral Raman Imaging.

Menglu Li, Yukiko Ueyama-Toba, Matthew Lindley, Gunganist Kongklad, Yasunori Nawa, Yasuaki Kumamoto, Seiichi Ishida, Yasunari Kanda, Satoshi Fujita, Hiroyuki Mizuguchi, Katsumasa Fujita.

To promote the clinical application of human induced pluripotent stem cell (hiPSC)-derived hepatocytes, a method capable of monitoring regenerative processes and assessing differentiation efficiency without harming or modifying these cells is important. Raman microscopy provides a powerful tool for this as it enables label-free identification of intracellular biomolecules in live samples. Here, we used label-free Raman microscopy to assess hiPSC differentiation into hepatocyte lineage based on the intracellular chemical content. We contrasted these data with similar phenotypes from the HepaRG and from commercially available hiPSC-derived hepatocytes (iCell hepatocytes). We detected hepatic cytochromes, lipids, and glycogen in hiPSC-derived hepatocyte-like cells (HLCs) but not biliary-like cells (BLCs), indicating intrinsic differences in biomolecular content between these phenotypes. The data show significant glycogen and lipid accumulation as early as the definitive endoderm transition. Additionally, we explored the use of Raman imaging as a hepatotoxicity assay for the HepaRG and iCell hepatocytes, with data displaying a dose-dependent reduction of glycogen accumulation in response to acetaminophen. These findings show that the nondestructive and high-content nature of Raman imaging provides a promising tool for both quality control of hiPSC-derived hepatocytes and hepatotoxicity screening.

DOI: https://doi.org/10.1021/acs.analchem.3c00976