bims-glecem 2022-05-01 papers

bims-glecem

Biomed News

on Glycogen metabolism in exercise, cancer and energy metabolism

Issue of 2022–05–01
fiveteen papers selected by
Dipsikha Biswas, Københavns Universitet

Genetic Variants of Glycogen Metabolism Genes Were Associated With Liver PDFF Without Increasing NAFLD Risk.
A novel compound heterozygous mutation in PYGM gene associated with McArdle's disease.
Prevalence of lower urinary tract symptoms in children with early-treated infantile-onset Pompe disease: A single-centre cross-sectional study.
Impact of obesity on the molecular response to a single bout of exercise in a preliminary human cohort.
Trypanosoma brucei brucei Induced Hypoglycaemia Depletes Hepatic Glycogen and Altered Hepatic Hexokinase and Glucokinase Activities in Infected Mice.
Cut-off values of neonatal lysosomal storage disease-related enzymes detected by tandem mass spectrometry.
Improved Metabolic Pathways of Glycolysis, Glycogen Synthesis, the Urea Cycle, and Cytochrome Peroxidase Oxidative Reabsorption in a Miniature Bioreactor.
Alpha-mangostin as an inhibitor of GSK3β in triple-negative breast cancer.
Antihyperglycemic and antidyslipidemic effects of Artemisia arborescens aqueous extract in streptozotocin-induced diabetic rat.
Daily running enhances molecular and physiological circadian rhythms in skeletal muscle.
A Comparison of Substrate Utilization Profiles During Maximal and Submaximal Exercise Tests in Athletes.
Placenta-specific lncRNA 1600012P17Rik is expressed in spongiotrophoblast and glycogen trophoblast cells of mouse placenta.
Paternal eNOS deficiency in mice affects glucose homeostasis and liver glycogen in male offspring without inheritance of eNOS deficiency itself.
Bredemolic acid restores glucose utilization and attenuates oxidative stress in palmitic acid-induced insulin-resistant C2C12 cells.
Assessment of RNA extraction protocols from cladocerans.

Front Genet. 2022 ;13 830445

Genetic Variants of Glycogen Metabolism Genes Were Associated With Liver PDFF Without Increasing NAFLD Risk.

Liu Yang, Zewen Sun, Jiuling Li, Xingchen Pan, Jianping Wen, Jianli Yang, Qing Wang, Peng Chen.

  Background/Aims: The storage amount of liver glycogen could affect the liver fibrosis assessment made by MRI-based methods. However, it remained unclear whether glycogen amount could bias the estimation of liver fat content by proton density fat fraction. In this study, we aimed to investigate whether glycogen metabolism gene variants could contribute to the bias of PDFF by genetic association. Methods: We conducted an association study of the glycogen metabolism genes based on the PDFF data of 11,129 participants in the UK Biobank. The effect of the SNPs in these genes on non-alcoholic fatty liver disease was estimated by a meta-analysis of the available NAFLD case-control studies. Results: We identified significant associations of the SNPs near the genes encoding glycogen phosphorylase (PYGM and PYGL) and synthase (GYS2) with PDFF (FDR-corrected p value < 0.05). The genes encoding the regulatory proteins of glycogenolysis (PHKB, CALM2/3), glucose transporter (SLC2A1), and glucose kinase (GCK) were also associated with PDFF. The SNP rs5402 of SLC2A2 and rs547066 of PYGM were associated with NAFLD (p < 0.05) with others being insignificant. Except for the PYGM gene, the PDFF-associated SNPs showed no associations with NAFLD. In addition, the burden tests of rare variants in these genes were not significant after FDR correction. Conclusion: Liver glycogen metabolism genes associated with PDFF were not associated with NAFLD, which implicated a potential bias effect of glycogen storage on the quantification of liver fat content by PDFF.

Keywords:  glycogen metabolism; glycogen phosphorylase; glycogen synthase; liver fat content; magnetic resonance imaging; non-alcoholic fatty liver disease; proton density fat fraction

DOI:  https://doi.org/10.3389/fgene.2022.830445
Acta Myol. 2022 Mar;41(1): 37-40

A novel compound heterozygous mutation in PYGM gene associated with McArdle's disease.

Salvatore Iacono, Antonino Lupica, Vincenzo Di Stefano, Eugenia Borgione, Filippo Brighina.

  McArdle's disease is an autosomal recessive glycogenosis due to mutation in the myophosphorylase gene (PYGM) resulting in a pure myopathy. The clinical onset typically occurs in childhood with cramps, myalgia, and intolerance to physical exercise, although late onset forms are also reported. We describe a case of a 17-year-old male complaining of cramps and myalgia following brief and intense exercise. The patient reported marked improvement in muscle fatigability few minutes after starting aerobic exercise. When he was a child, he had experienced few episodes of vomiting, nausea, and black colored urine following physical activity. Laboratory testings revealed high creatine kinase serum levels. Genetic testings for metabolic myopathies demonstrated a compound heterozygous for two PYGM mutations (p.R570Q and p.K754Nfs*49) allowing the diagnosis of McArdle's disease. To date, 183 mutations in the PYGM gene are listed in Human Gene Mutation Database Professional 2021.2, but this novel compound heterozygosis has never been reported before.

Keywords:  McArdle’s disease; PYGM; glycogenosis; hyperCKemia; second wind phenomenon

DOI:  https://doi.org/10.36185/2532-1900-067
Neurourol Urodyn. 2022 Apr 28.

Prevalence of lower urinary tract symptoms in children with early-treated infantile-onset Pompe disease: A single-centre cross-sectional study.

Yu-Kuang Chen, Chao-Ting Teng, Chia-Feng Yang, Dau-Ming Niu, William J Huang, Yu-Hua Fan.

   AIM: To evaluate lower urinary tract symptoms (LUTS) in children with infantile-onset Pompe disease (IOPD) who received early treatment.
METHODS: Pompe disease (PD), or glycogen storage disease II is a rare autosomal recessive lysosomal storage disease that affects multiple organ systems. To our knowledge, only one study has focused on the relationship between LUTS and incontinence in children with PD. This cross-sectional study was conducted from August 2019 through March 2021 and children with IOPD, who had received early and regular enzyme replacement therapy, were enrolled. Participants or their parents completed the Dysfunctional Voiding Scoring System (DVSS) questionnaire. All children underwent uroflowmetry and postvoid residual urine measurements. Fourteen children (age, 4-9 years) with IOPD were enrolled.
RESULTS: Ten patients (71.4%) had abnormal uroflow curves. In addition, results of the DVSS revealed that approximately half (42.9%) of our IOPD patients had voiding dysfunction, with urinary incontinence as the most common symptom (64.3%, 9/14). No significant correlations were found between LUTS and uroflow curves in children with IOPD.
CONCLUSIONS: The frequency of LUTS and lower urinary tract dysfunction noted on uroflowmetry should encourage pediatricians to actively identify IOPD patients with LUTS, regardless of the timing and frequency of their treatments, and refer them to a urologist for further evaluation and appropriate treatment.

Keywords:  Pompe disease; dysfunctional voiding; glycogen storage disease; lower urinary tract symptoms; pediatrics postvoid residual urine; uroflowmetry

DOI:  https://doi.org/10.1002/nau.24950
Obesity (Silver Spring). 2022 May;30(5): 1091-1104

Impact of obesity on the molecular response to a single bout of exercise in a preliminary human cohort.

Patrick Vanderboom, Xiaoyan Zhang, Corey R Hart, Hawley E Kunz, Kevin J Gries, Carrie J Heppelmann, Yuanhang Liu, Surendra Dasari, Ian R Lanza.

OBJECTIVE: The health benefits of exercise are well documented, but several exercise-response parameters are attenuated in individuals with obesity. The goal of this pilot study was to identify molecular mechanisms that may influence exercise response with obesity.
METHODS: A multi-omics comparison of the transcriptome, proteome, and phosphoproteome in muscle from a preliminary cohort of lean individuals (n = 4) and individuals with obesity (n = 4) was performed, before and after a single bout of 30 minutes of unilateral cycling at 70% maximal oxygen uptake (VO2 peak). Mass spectrometry and RNA sequencing were used to interrogate the proteome, phosphoproteome, and transcriptome from muscle biopsy tissue.
RESULTS: The main findings are that individuals with obesity exhibited transcriptional and proteomic signatures consistent with reduced mitochondrial function, protein synthesis, and glycogen synthesis. Furthermore, individuals with obesity demonstrated markedly different transcriptional, proteomic, and phosphoproteomic responses to exercise, particularly biosynthetic pathways of glycogen synthesis and protein synthesis. Casein kinase II subunit alpha and glycogen synthase kinase-3β signaling was identified as exercise-response pathways that were notably altered by obesity.
CONCLUSIONS: Opportunities to enhance exercise responsiveness by targeting specific molecular pathways that are disrupted in skeletal muscle from individuals with obesity await a better understanding of the precise molecular mechanisms that may limit exercise-response pathways in obesity.

DOI: https://doi.org/10.1002/oby.23419
Acta Parasitol. 2022 Apr 27.

Trypanosoma brucei brucei Induced Hypoglycaemia Depletes Hepatic Glycogen and Altered Hepatic Hexokinase and Glucokinase Activities in Infected Mice.

Rotimi Johnson Ojo, Grace Manmak Paul, Dorcas Dedan Magellan, Dogwo Nahum Dangara, Gideon Gyebi.

   PURPOSE: Little progress has been made in understanding the effect of Trypanosoma brucei brucei infection that was allowed to run its course without treatment on human and animal carbohydrate metabolism even though most of the symptoms associated with the disease can be clearly linked with interference with host energy generation. The present study therefore assessed the course of untreated Trypanosoma brucei brucei infection on hepatic glycogen, hepatic hexokinase and glucokinase activities.
METHODS: Mice were grouped into two: control and infected group. Trypanosomiasis was induced by intraperitoneal inoculation of 1 × 104 parasites/mice in 0.3 ml of phosphate saline glucose. The infection was allowed to run its course until the first mortality was recorded with all the mice showing chronic symptoms of the second stage of the disease before the research was terminated. Blood and liver samples were collected from the mice in each group for the assessment of hepatic glycogen and total protein, hepatic hexokinase and glucokinase activities, liver biomarkers, blood glucose and protein with packed cell volume.
RESULTS: The infection resulted in decrease in blood glucose, hepatic glycogen, liver protein, PCV, hepatic hexokinase and glucokinase activities, but increase in serum total protein and liver biomarkers.
CONCLUSION: Trypanosomiasis negatively affects hepatic integrity, resulting in the depletion of hepatic glycogen content and suppression of both hepatic hexokinase and glucokinase activities. The suppression of hepatic hexokinase and glucokinase activities suggested that trypanosomiasis affected the oxidation of glucose and host energy generation via glycolysis. This probably denied the host of the needed energy which is likely the reason for early death in untreated African trypanosomiasis.

Keywords:  Glucokinase; Glycogen; Hexokinase; Liver; Trypanosoma brucei brucei

DOI:  https://doi.org/10.1007/s11686-022-00550-4
Zhejiang Da Xue Xue Bao Yi Xue Ban. 2021 Mar 25. 50(7): 1-5

Cut-off values of neonatal lysosomal storage disease-related enzymes detected by tandem mass spectrometry.

Gaijie Li, Liping Tian, Yuanfang Guo, Yulin Li, Meng Sun, Hui Zou.

  To establish cut-off values of lysosomal storage disease (LSD)-related enzymes by tandem mass spectrometry. A total of 26 689 newborns and 7 clinically confirmed LSD children underwent screening for LSDs (glycogen storage disease typeⅡ, Fabry disease, mucopolysaccharidosis type Ⅰ, Krabbe disease, Niemann-Pick disease A/B and Gaucher disease). The activities of LSD-related enzymes were detected by tandem mass spectrometry. The 20% of the median enzyme activity of each batch of acid β-glucocerebrosidase, acid sphingomyelinase, β-galactocerebroside, α--iduronidase and acid α-glucosidase, and the 30% of the median enzyme activity of were taken as cut-off values of corresponding enzymes. The genetic diagnosis was performed in neonates whose enzyme activity was lower than 70% of the cut-off value. The enzyme activities of 7 clinically confirmed cases were all lower than the cut-off values. Among 26 689 newborns, 142 cases (0.53%) were suspected positive for LSDs, including 25 cases of β-galactocerebroside deficiency, 1 case of α--iduronidase deficiency, 19 cases of α-galactosidase deficiency, and 97 cases of acid α-glucosidase deficiency. Eight infants were genetically diagnosed with LSDs, including 3 cases of glycogen storage disease type Ⅱ, 3 cases of Krabbe disease, and 2 cases of Fabry disease, with a positive predictive value of about 5.6%. Cut-off values of the six LSD enzyme activities all showed a downward trend from March to August, and an upward trend from September to December. There was a statistically significant difference in LSD enzyme activity among different months (<0.05). The established cut-off values of LSD-related enzyme activities detected by tandem mass spectrometry can be used for screening LSDs in neonates, and the enzyme activity would be affected by temperature and humidity.

Keywords:  Cut value; Enzyme activity; Lysosomal storage disease; Newborn screening; Tandem mass spectrometry

DOI:  https://doi.org/10.3724/zdxbyxb-2022-0095
Cell Physiol Biochem. 2022 Apr 25. 56(2): 209-222

Improved Metabolic Pathways of Glycolysis, Glycogen Synthesis, the Urea Cycle, and Cytochrome Peroxidase Oxidative Reabsorption in a Miniature Bioreactor.

Shibashish Giri, Wolfgang Schmidt-Heck, Augustinus Bader.

   BACKGROUND/AIMS: Bioreactor-based bioartificial liver support systems have had limited success in a translational setting and at preclinical stages. None of the existing systems monitor the metabolic pathways of glycolysis, glycogen synthesis, the urea cycle, and cytochrome peroxidase oxidative reabsorption. Herein, we designed a bioreactor that mimics the human liver microenvironment in vivo and monitors different hepatic metabolic pathways in order to help establish in vitro culture conditions for improved glycolysis, glycogen synthesis, the urea cycle, cytochrome peroxidase oxidative reabsorption and improved hepatic functions in a miniature bioartificial liver. An abnormality in such pathways negatively influences survivability and hepatic functions, including spontaneous liver regeneration.
METHODS: We investigated the metabolic functions of primary mouse adult hepatocytes cultured in a three-dimensional configuration under direct oxygenation conditions (5%, 10%, 20%, and 40% O2) for 14 days in the bioreactor. We analyzed the expression of the genes of hepatic metabolic pathways, such as glycolysis (glucokinase, phosphofructokinase, and pyruvate kinase), glycogen synthesis (glycogen synthetase, UTP glucose-1-phosphate uridylylisomerase, phosphoglucomutase, and glycogen phosphorylase), the urea cycle (arginase, ornithine carbomoyltransferase, fumarate hydratase), oxidative reabsorption (peroxidase), and cytochrome peroxides (catalase and superoxide dismutase), and compared it with the level in vivo. The metabolic mini-map was used to represent the above-mentioned metabolic genes.
RESULTS: Increased urea secretion under normoxia and hyperoxia conditions (20% and 40% O2, respectively) was observed, while albumin secretion was decreased in hyperoxic cultures. Lactate formation was up to 15 mg/L-g/h-h/106 cells, 2 mg/L-g/h-h/106 cells, and 0.2 mg/L-c/h-h/106 cells in 5%, 20%, and 40% O2 conditions, respectively while glucose consumption was enhanced under hypoxic conditions (5% and 10% O2). Cellular membrane integrity was estimated by lactate dehydrogenase assay and was found to be negligible in only 20% and 40% O2 conditions. The expression of the phase II enzyme UDP-glucuronosyltransferase was only upregulated in 20% oxygenation.
CONCLUSION: Taken together, 20% O2 was found to be an optimal condition for the long-term culture (up to 14 days) of hepatocytes that promoted the expression of genes in metabolic pathways such as glycolysis, glycogen synthesis, the urea cycle, and cytochrome peroxidase oxidative reabsorption, and improved hepatic functions in a miniature bioreactor for bioartificial liver construction.

Keywords:  Bioartificial liver; Glycolysis; Gluconeogenesis; Lactate; Oxygen; Miniature bioreactor; Urea cycle

DOI:  https://doi.org/10.33594/000000513
J Biomol Struct Dyn. 2022 Apr 23. 1-7

Alpha-mangostin as an inhibitor of GSK3β in triple-negative breast cancer.

Citra Dewi, Adryan Fristiohady, Riezki Amalia, Edwin J Bunggulawa, Muchtaridi Muchtaridi.

  Triple-negative breast cancer (TNBC) is a breast cancer subtype that does not express the estrogen receptor, the progesterone receptor, or the human epidermal growth factor receptor 2 and that is characterized by high invasiveness, high metastatic potential, and poor prognosis. TNBC lacks receptors and hence cannot be treated by using targeted therapies; as such, the therapeutic potential of Indonesian herbal plants against this disease is worth exploring. Herein, we explore the molecular docking and the molecular dynamics simulations of α-mangostin on glycogen synthase kinase 3β (GSK3β; PDB ID: 4ACC). Our findings reveal that α-mangostin has a weaker binding affinity to GSK3β than the native ligand (-8.22 kcal/mol), while the latter binds to GSK3β with a stronger binding affinity of -8.92 kcal/mol. According to the binding site analysis, the hydrogen bonds of the native ligand on Asp133 and Arg141, while α-mangostin only appeared to form a hydrogen bond on the enzyme's Asp133. On the other hand, α-mangostin shares similar docking sites with the native ligand (namely, Ile62, Phe67, Val70, and Thr138), thus leading to the conclusion that the native ligand and α-mangostin might share a similar molecular mechanism. The molecular dynamics simulation by using the molecular mechanics Poisson-Boltzmann and surface area (MM-PBSA) calculations' method shows that α-mangostin maintains a better affinity (with a value of ΔGTotal at -114.463 kJ/mol) as compared with the native ligand (with a respective ΔGTotal value of -75.158 kJ/mol). Our findings are suggestive of α-mangostin possessing a valuable potential as an anti-TNBC agent through GSK3β inhibition.Communicated by Ramaswamy H. Sarma.

Keywords:  GSK3β; Triple-negative breast cancer; molecular docking; molecular dynamics; α-mangostin

DOI:  https://doi.org/10.1080/07391102.2022.2068074
Cardiovasc Hematol Agents Med Chem. 2022 Apr 25.

Antihyperglycemic and antidyslipidemic effects of Artemisia arborescens aqueous extract in streptozotocin-induced diabetic rat.

Amine Azzane, Omar Farid, Mohamed Eddouks.

   AIMS: The study aimed to investigate the antidiabetic activity of Artemisia arborescens.
BACKGROUND: Artemisia arborescens is an aromatic, medicinal, and endemic plant in Mediterranean region. This plant is widely used in alternative medicine.
OBJECTIVE: The study was designed to examine the antihyperglycemic and antihyperlipidemic activities of Artemisia arborescens aqueous extract (AEAA) in normal and streptozotocin(STZ)- induced diabetic rats.
METHODS: The effect of AEAA (40 mg/kg and 80 mg/kg) on plasma glucose levels and plasma lipid profile was investigated in normal and STZ-induced diabetic rats. The plasma glucose levels were determined after a single (6 hours) and subchronic oral administration (7 days) and plasma lipid profiles have been evaluated after both acute and subchronic oral administration. Additionally, the glycogen content in the liver, extensor digitorum longus (EDL), and soleus muscles was measured using a standard method. Moreover, the aqueous extract was tested for its 1.1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity.
RESULTS: In diabetic rats, AEAA oral administration (40 mg/kg and 80 mg/kg) produced a significant decrease of blood glucose levels after 7 days of oral administration (p<0.0001). Moreover, a significant decrease of plasma triglyceride levels was registered at the last day of treatment by AEAA (80 mg/kg) (p<0.05). Furthermore, a significant decrease of total cholesterol levels has been shown after 7 days of AEAA oral administration in diabetic rats (p<0.01). Moreover, a significant increase of HDL-c concentration was produced after one week of AEAA (80 mg/kg) oral administration (p<0.001). In addition, AEAA oral administration (80 mg/kg) has significantly increased the glycogen content in the liver and extensor digitorum longus (p<0.05). On the other hand, qualitative and quantitative phytochemical screenings have revealed the presence of various compounds such as polyphenols, flavonoids, and tannins.
CONCLUSION: In summary, the study demonstrates that Artemisia arborescens oral administration exhibited a significant antihyperglycemic effect in diabetic rats and revealed a significant amelioration in lipid profile and glycogen content.

Keywords:  Antihyperglycemic; Artemisia arborescens; antihyperlipidemic; medicinal plant; streptozotocin

DOI:  https://doi.org/10.2174/1871525720666220425094135
Mol Metab. 2022 Apr 22. pii: S2212-8778(22)00073-4. [Epub ahead of print] 101504

Daily running enhances molecular and physiological circadian rhythms in skeletal muscle.

Nuria Casanova-Vallve, Drew Duglan, Megan E Vaughan, Marie Pariollaud, Michal K Handzlik, Weiwei Fan, Ruth T Yu, Christopher Liddle, Michael Downes, Julien Delezie, Rebecca Mello, Alanna B Chan, Pål O Westermark, Christian M Metallo, Ronald M Evans, Katja A Lamia.

   OBJECTIVE: Exercise is a critical component of a healthy lifestyle and a key strategy for the prevention and management of metabolic disease. Identifying molecular mechanisms underlying adaptation in response to chronic physical activity is of critical interest in metabolic physiology. Circadian rhythms broadly modulate metabolism, including muscle substrate utilization and exercise capacity. Here, we define the molecular and physiological changes induced across the daily cycle by voluntary low intensity daily exercise.
METHODS: Wildtype C57BL6/J male and female mice were housed with or without access to a running wheel for six weeks. Maximum running speed was measured at four different zeitgeber times (ZTs, hours after lights on) using either electrical or manual stimulation to motivate continued running on a motorized treadmill. RNA isolated from plantaris muscles at six ZTs was sequenced to establish the impact of daily activity on genome-wide transcription. Patterns of gene expression were analyzed using Gene Set Enrichment Analysis (GSEA) and Detection of Differential Rhythmicity (DODR). Blood glucose, lactate, and ketones, and muscle and liver glycogen were measured before and after exercise.
RESULTS: We demonstrate that the use of mild electrical shocks to motivate running negatively impacts maximum running speed in mice, and describe a manual method to motivate running in rodent exercise studies. Using this method, we show that time of day influences the increase in exercise capacity afforded by six weeks of voluntary wheel running: when maximum running speed is measured at the beginning of the nighttime active period in mice, there is no measurable benefit from a history of daily voluntary running, while maximum increase in performance occurs at the end of the night. We show that daily voluntary exercise dramatically remodels the murine muscle circadian transcriptome. Finally, we describe daily rhythms in carbohydrate metabolism associated with the time-dependent response to moderate daily exercise in mice.
CONCLUSIONS: Collectively, these data indicate that chronic nighttime physical activity dramatically remodels daily rhythms of murine muscle gene expression, which in turn support daily fluctuations in exercise performance.

Keywords:  Circadian Clock; Exercise; Glycogen; Metabolism; Muscle

DOI:  https://doi.org/10.1016/j.molmet.2022.101504
Front Psychol. 2022 ;13 854451

A Comparison of Substrate Utilization Profiles During Maximal and Submaximal Exercise Tests in Athletes.

Rohit Ramadoss, Joseph R Stanzione, Stella Lucia Volpe.

   Background: Exercise is primarily sustained by energy derived from lipids (plasma free fatty acids and intramuscular triglycerides), and glucose (plasma glucose and muscle glycogen). Substrate utilization is the pattern by which these fuel sources are used during activity. There are many factors that influence substrate utilization. We aim to delineate the effect of exercise intensity and body composition on substrate utilization.
Objective: The objective of our study was to discern the differences in substrate utilization profiles during a maximal and submaximal graded exercise test, and to determine the extent to which body composition influences substrate utilization during the exercise tests.
Methods: A total of 27 male athletes, 32.5 ± 11 years of age, were recruited for this study. Body composition was analyzed using a bioelectrical impedance analyzer. Maximal and submaximal exercise tests were performed on a treadmill. A novel graded submaximal treadmill protocol was used for the submaximal test.
Results: Average percent body fat (PBF) was 15.8 ± 5%. Average maximal oxygen consumption (VO2max) was 47.6 ± 9 mL/kg/min, while the average exercise intensity (percent VO2max) at which participants were shifting to glucose predominance for energy during the maximal and submaximal tests were 76 ± 8.3% and 58.4 ± 21.1%, respectively. A paired-samples t-test was conducted to compare percent VO2max at crossover point in maximal and submaximal graded exercise tests. There was a significant difference in percent VO2max at the crossover point for maximal (76 ± 8.3%) and submaximal (58 ± 21.1%) tests (t = 4.752, p = 0.001). A linear regression was performed to elucidate the interaction between exercise intensity at the crossover point and body composition during a maximal and submaximal graded exercise test. There was a significant effect of PBF on percent VO2max at crossover point during the maximal graded exercise test [F(1,24) = 9.10, P = 0.006] with an R2 of 0.245. However, there was no significant effect of PBF on percent VO2max at crossover point during the submaximal graded exercise test (P > 0.05).
Conclusion: Substrate utilization, represented by the crossover point, is dependent on the rate of increase in exercise intensity. At maximal efforts, the crossover to carbohydrates from fats as the predominant fuel source occurs at a significantly later stage of percent VO2max than at submaximal efforts. Furthermore, body composition represented by PBF is a significant predictor of substrate utilization during maximal efforts. Athletes with a relatively higher PBF are more likely to have increased lipid oxidation during high intensity exercises than those with a lower body fat percentage.

Keywords:  carbohydrate; combat athletes; fat; runners; substrate utilization

DOI:  https://doi.org/10.3389/fpsyg.2022.854451
Histochem Cell Biol. 2022 Apr 29.

Placenta-specific lncRNA 1600012P17Rik is expressed in spongiotrophoblast and glycogen trophoblast cells of mouse placenta.

Junxiao Wang, Syunya Noguchi, Takami Takizawa, Yasuyuki Negishi, Rimpei Morita, Shan-Shun Luo, Toshihiro Takizawa.

  A few long noncoding RNAs (long ncRNAs, lncRNAs) exhibit trophoblast cell type-specific expression patterns and functional roles in mouse placenta. However, the cell- and stage-specific expression patterns and functions of most placenta-derived lncRNAs remain unclear. In this study, we explored mouse placenta-associated lncRNAs using a combined bioinformatic and experimental approach. We used the FANTOM5 database to survey lncRNA expression in mouse placenta and found that 1600012P17Rik (MGI: 1919275, designated P17Rik), a long intergenic ncRNA, was the most highly expressed lncRNA at gestational day 17. Polymerase chain reaction analysis confirmed that P17Rik was exclusively expressed in placenta and not in any of the adult organs examined in this study. In situ hybridization analysis revealed that it was highly expressed in spongiotrophoblast cells and to a lesser extent in glycogen trophoblast cells, including migratory glycogen trophoblast cells invading the decidua. Moreover, we found that it is a polyadenylated lncRNA localized mainly to the cytoplasm of these trophoblast cells. As these trophoblast cells also expressed the neighboring protein-coding gene, pappalysin 2 (Pappa2), we investigated the effects of P17Rik on Pappa2 expression using Pappa2-expressing MC3T3-E1 cells and found that P17Rik transfection increased the messenger RNA (mRNA) and protein levels of Pappa2. These results indicate that mouse placenta-specific lncRNA P17Rik modulates the expression of the neighboring protein-coding gene Pappa2 in spongiotrophoblast and glycogen trophoblast cells of mouse placenta during late gestation.

Keywords:  1600012P17Rik; In situ hybridization; Long noncoding RNA; Mouse placenta; Pappa2

DOI:  https://doi.org/10.1007/s00418-022-02109-w
Diabetologia. 2022 Apr 30.

Paternal eNOS deficiency in mice affects glucose homeostasis and liver glycogen in male offspring without inheritance of eNOS deficiency itself.

Berthold Hocher, Yong-Ping Lu, Christoph Reichetzeder, Xiaoli Zhang, Oleg Tsuprykov, Jan Rahnenführer, Li Xie, Jian Li, Liang Hu, Bernhard K Krämer, Ahmed A Hasan.

   AIMS/HYPOTHESIS: It was shown that maternal endothelial nitric oxide synthase (eNOS) deficiency causes fatty liver disease and numerically lower fasting glucose in female wild-type offspring, suggesting that parental genetic variants may influence the offspring's phenotype via epigenetic modifications in the offspring despite the absence of a primary genetic defect. The aim of the current study was to analyse whether paternal eNOS deficiency may cause the same phenotype as seen with maternal eNOS deficiency.
METHODS: Heterozygous (+/-) male eNOS (Nos3) knockout mice or wild-type male mice were bred with female wild-type mice. The phenotype of wild-type offspring of heterozygous male eNOS knockout mice was compared with offspring from wild-type parents.
RESULTS: Global sperm DNA methylation decreased and sperm microRNA pattern altered substantially. Fasting glucose and liver glycogen storage were increased when analysing wild-type male and female offspring of +/- eNOS fathers. Wild-type male but not female offspring of +/- eNOS fathers had increased fasting insulin and increased insulin after glucose load. Analysing candidate genes for liver fat and carbohydrate metabolism revealed that the expression of genes encoding glucocorticoid receptor (Gr; also known as Nr3c1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Pgc1a; also known as Ppargc1a) was increased while DNA methylation of Gr exon 1A and Pgc1a promoter was decreased in the liver of male wild-type offspring of +/- eNOS fathers. The endocrine pancreas in wild-type offspring was not affected.
CONCLUSIONS/INTERPRETATION: Our study suggests that paternal genetic defects such as eNOS deficiency may alter the epigenome of the sperm without transmission of the paternal genetic defect itself. In later life wild-type male offspring of +/- eNOS fathers developed increased fasting insulin and increased insulin after glucose load. These effects are associated with increased Gr and Pgc1a gene expression due to altered methylation of these genes.

Keywords:  Glucocorticoid receptor; Insulin resistance; PGC1a; Paternal programming; eNOS

DOI:  https://doi.org/10.1007/s00125-022-05700-x
Endocr Regul. 2022 Apr 30. 56(2): 126-133

Bredemolic acid restores glucose utilization and attenuates oxidative stress in palmitic acid-induced insulin-resistant C2C12 cells.

Karabo R Matee, Akinjide M Akinnuga, Angezwa Siboto, Phikelelani Ngubane, Andile Khathi.

  Objective. Due to insulin resistance and oxidative stress that are associated with type 2 diabetes mellitus (T2DM), T2DM has become a prevalent metabolic disorder that presents various side effects. However, alternative antidiabetic treatment has commonly been used in treating diabetes mellitus in diabetic patients. In our previous studies, bredemolic acid has been reported as an antidiabetic agent that improves glucose uptake, ameliorates insulin resistance, and oxidative stress in the liver, heart, kidney, and skeletal muscle of prediabetic rats. However, these effects have not been validated in vitro. Therefore, this study was aimed to investigate the effects of bredemolic acid on insulin-mediated glucose utilization, lipid peroxidation, and the total antioxidant capacity (TOAC) in palmitic acid-induced insulin-resistant C2C12 skeletal muscle cells in vitro. Methods. Insulin resistance was induced in the skeletal muscle cells after 4 h of exposure to palmitic acid (0.5 mmol/l). Different cell groups were incubated in culture media DMEM supplemented with fetal calf serum (10%), penicillin/streptomycin (1%), and L-glutamine (1%) and then treated with either insulin (4 µg/ml) or bredemolic acid (12.5 mmol/l) or with both. Thereafter, the cells were seeded in 24- or 96-well plates for determination of the cell viability, glucose utilization, glycogen formation, and antioxidant capacity. Results. The results showed that bredemolic acid significantly improved TOAC and promoted glucose utilization via attenuation of lipid peroxidation and increased glycogen formation in the insulin-resistant cells, respectively. Conclusion. This study showed that bredemolic acid restored the insulin resistance through improved glucose utilization, glycogen formation, and TOAC in the skeletal muscle cells.

Keywords:  C2C12 cell; bredemolic acid; glucose utilization; insulin resistance; oxidative stress; skeletal muscle cell

DOI:  https://doi.org/10.2478/enr-2022-0014
PLoS One. 2022 ;17(4): e0264989

Assessment of RNA extraction protocols from cladocerans.

Muhammad Raznisyafiq Razak, Ahmad Zaharin Aris, Fatimah Md Yusoff, Zetty Norhana Balia Yusof, Sang Don Kim, Kyoung Woong Kim.

The usage of cladocerans as non-model organisms in ecotoxicological and risk assessment studies has intensified in recent years due to their ecological importance in aquatic ecosystems. The molecular assessment such as gene expression analysis has been introduced in ecotoxicological and risk assessment to link the expression of specific genes to a biological process in the cladocerans. The validity and accuracy of gene expression analysis depends on the quantity, quality and integrity of extracted ribonucleic acid (RNA) of the sample. However, the standard methods of RNA extraction from the cladocerans are still lacking. This study evaluates the extraction of RNA from tropical freshwater cladocerans Moina micrura using two methods: the phenol-chloroform extraction method (QIAzol) and a column-based kit (Qiagen Micro Kit). Glycogen was introduced in both approaches to enhance the recovery of extracted RNA and the extracted RNA was characterised using spectrophotometric analysis (NanoDrop), capillary electrophoresis (Bioanalyzer). Then, the extracted RNA was analysed with reverse transcription polymerase chain reaction (RT-PCR) to validate the RNA extraction method towards downstream gene expression analysis. The results indicate that the column-based kit is most suitable for the extraction of RNA from M. micrura, with the quantity (RNA concentration = 26.90 ± 6.89 ng/μl), quality (A260:230 = 1.95 ± 0.15, A280:230 = 1.85 ± 0.09) and integrity (RNA integrity number, RIN = 7.20 ± 0.16). The RT-PCR analysis shows that the method successfully amplified both alpha tubulin and actin gene at 33-35 cycles (i.e. Ct = 32.64 to 33.48). The results demonstrate that the addition of glycogen is only suitable for the phenol-chloroform extraction method. RNA extraction with high and comprehensive quality control assessment will increase the accuracy and reliability of downstream gene expression, thus providing more ecotoxicological data at the molecular biological level on other freshwater zooplankton species.

DOI: https://doi.org/10.1371/journal.pone.0264989