Primary defects in lipid handling and resistance to exercise in myotubes from obese donors with and without type 2 diabetes

Several studies have shown that human primary myotubes retain the metabolic characteristic of their donors in vitro. We have demonstrated, along with other researchers, a reduced lipid turnover and fat oxidation rate in myotubes derived from obese donors with and without type 2 diabetes (T2D). Because exercise is known to increase fat oxidative capacity in skeletal muscle, we investigated if in vitro exercise could restore primary defects in lipid handling in myotubes of obese individuals with and without T2D compared with lean nondiabetic donors. Primary myotubes cultures were derived from biopsies of lean, obese, and T2D subjects. One single bout of long-duration exercise was mimicked in vitro by electrical pulse stimulation (EPS) for 24 h. Lipid handling was measured using radiolabeled palmitate, metabolic gene expression by real-time qPCR, and proteins by Western blot. We first showed that myotubes from obese and T2D donors had increased uptake and incomplete oxidation of palmitate. This was associated with reduced mitochondrial respiratory chain complex II, III, and IV protein expression in myotubes from obese and T2D subjects. EPS stimulated palmitate oxidation in lean donors, while myotubes from obese and T2D donors were refractory to this effect. Interestingly, EPS increased total palmitate uptake in myotubes from lean donors while myotubes from T2D donors had a reduced rate of palmitate uptake into complex lipids and triacylglycerols. Novelty Myotubes from obese and T2D donors are characterized by primary defects in palmitic acid handling. Both obese and T2D myotubes are partially refractory to the beneficial effect of exercise on lipid handling.

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Astaxanthin extends lifespan via altered biogenesis of the mitochondrial respiratory chain complex III

10.1101/698001 ◽

2019 ◽

Cited By ~ 3

Author(s):

Ronit Hoffman ◽

Laure D. Sultan ◽

Ann Saada ◽

Joseph Hirschberg ◽

Oren Osterzetser-Biran ◽

...

Keyword(s):

Model Organism ◽

Chain Complex ◽

Mitochondrial Respiratory Chain ◽

Industrial Applications ◽

Complex Iii ◽

Life Extension ◽

Mitochondrial Respiratory Chain Complex ◽

C Elegans ◽

Species Effect

AbstractAstaxanthin is a keto-carotenoid produced in some bacteria and algae, which has very important industrial applications (i.e., in cosmetics, coloring additive in aquaculture and as a dietary supplement for human). Here, we analyzed the molecular basis of Astaxanthin-mediated prolongevity in the model organism, Caenorhabditis elegans. The increased lifespan effects of Astaxanthin are restricted in C. elegans to the adult phase and are uninfluenced by various other carotenoids tested. Genetic analyses indicated that the Astaxanthin-mediated life-extension relies on mitochondria activity, via the Rieske iron-sulfur polypeptide-1 (ISP-1), but is not influenced by the functions of other known longevity-related gene-loci, including CLK-1, DAF-2, DAT-16, EAT-2, GAS-1 GLP-1 or MEV-1. Biochemical analyses of native respiratory complexes showed that Astaxanthin affects the biogenesis of holo-complex III (and likely supercomplex I+III, as well). Effects on holo-CIII assembly and activity were also indicated by in-vitro assays, with mitochondria isolated from worms, rodents, human and plants, which were treated with Astaxanthin. These data indicated a cross-species effect on the oxidative phosphorylation (OXPHOS) machinery by the carotenoid, and provide with further insights into the molecular mechanism of animals longevity extension by Astaxanthin.Significance StatementAstaxanthin is a widely consumed pigment by animals and human. In this study we find that Astaxanthin, but not other tested carotenoids, significantly extends the lifespan of animals by affecting respiratory complex III (CIII) biogenesis of the mitochondria, in plants, C. elegans, rodents and human. We further propose a model to try explaining this effect of astaxanthin on animals’ longevity.

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Dihydromyricetin Attenuates Dexamethasone-Induced Muscle Atrophy by Improving Mitochondrial Function via the PGC-1α Pathway

Cellular Physiology and Biochemistry ◽

10.1159/000493040 ◽

2018 ◽

Vol 49 (2) ◽

pp. 758-779 ◽

Cited By ~ 15

Author(s):

Yujie Huang ◽

Ka Chen ◽

Qingbo Ren ◽

Long Yi ◽

Jundong Zhu ◽

...

Keyword(s):

Muscle Atrophy ◽

Mitochondrial Function ◽

Chain Complex ◽

Mitochondrial Respiratory Chain ◽

Mitochondrial Morphology ◽

Cross Sectional ◽

Mitochondrial Respiratory Chain Complex ◽

Underlying Mechanisms ◽

Complex Activities

Background/Aims: Skeletal muscle atrophy is an important health issue and can impose tremendous economic burdens on healthcare systems. Glucocorticoids (GCs) are well-known factors that result in muscle atrophy observed in numerous pathological conditions. Therefore, the development of effective and safe therapeutic strategies for GC-induced muscle atrophy has significant clinical implications. Some natural compounds have been shown to effectively prevent muscle atrophy under several wasting conditions. Dihydromyricetin (DM), the most abundant flavonoid in Ampelopsis grossedentata, has a broad range of health benefits, but its effects on muscle atrophy are unclear. The purpose of this study was to evaluate the effects and underlying mechanisms of DM on muscle atrophy induced by the synthetic GC dexamethasone (Dex). Methods: The effects of DM on Dex-induced muscle atrophy were assessed in Sprague-Dawley rats and L6 myotubes. Muscle mass and myofiber cross-sectional areas were analyzed in gastrocnemius muscles. Muscle function was evaluated by a grip strength test. Myosin heavy chain (MHC) content and myotube diameter were measured in myotubes. Mitochondrial morphology was observed by transmission electron microscopy and confocal laser scanning microscopy. Mitochondrial DNA (mtDNA) was quantified by real-time PCR. Mitochondrial respiratory chain complex activities were examined using the MitoProfile Rapid Microplate Assay Kit, and mitochondrial membrane potential was assessed by JC-1 staining. Protein levels of mitochondrial biogenesis and dynamics markers were detected by western blotting. Myotubes were transfected with siRNAs targeting peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), mitochondrial transcription factor A (TFAM) and mitofusin-2 (mfn2) to determine the underlying mechanisms. Results: In vivo, DM preserved muscles from weight and average fiber cross-sectional area losses and improved grip strength. In vitro, DM prevented the decrease in MHC content and myotube diameter. Moreover, DM stimulated mitochondrial biogenesis and promoted mitochondrial fusion, rescued the reduced mtDNA content, improved mitochondrial morphology, prevented the collapse in mitochondrial membrane potential and enhanced mitochondrial respiratory chain complex activities; these changes restored mitochondrial function and improved protein metabolism, contributing to the prevention of Dex-induced muscle atrophy. Furthermore, the protective effects of DM on mitochondrial function and muscle atrophy were alleviated by PGC-1α siRNA, TFAM siRNA and mfn2 siRNA transfection in vitro. Conclusion: DM attenuated Dex-induced muscle atrophy by reversing mitochondrial dysfunction, which was partially mediated by the PGC-1α/TFAM and PGC-1α/mfn2 signaling pathways. Our findings may open new avenues for identifying natural compounds that improve mitochondrial function as promising candidates for the management of muscle atrophy.

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31P MR spectroscopy and in vitro markers of oxidative capacity in type 2 diabetes patients

Magnetic Resonance Materials in Physics Biology and Medicine ◽

10.1007/s10334-006-0060-0 ◽

2006 ◽

Vol 19 (6) ◽

pp. 321-331 ◽

Cited By ~ 24

Author(s):

S. F. E. Praet ◽

H. M. M. De Feyter ◽

R. A. M. Jonkers ◽

K. Nicolay ◽

C. van Pul ◽

...

Keyword(s):

Type 2 Diabetes ◽

Mr Spectroscopy ◽

Oxidative Capacity ◽

31P Mr Spectroscopy ◽

Diabetes Patients

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Myotubes from lean and severely obese subjects with and without type 2 diabetes respond differently to an in vitro model of exercise

AJP Cell Physiology ◽

10.1152/ajpcell.00314.2014 ◽

2015 ◽

Vol 308 (7) ◽

pp. C548-C556 ◽

Cited By ~ 20

Author(s):

Yuan Z. Feng ◽

Nataša Nikolić ◽

Siril S. Bakke ◽

Eili T. Kase ◽

Kari Guderud ◽

...

Keyword(s):

Type 2 Diabetes ◽

Insulin Sensitivity ◽

Mrna Expression ◽

In Vitro Model ◽

Oxidative Capacity ◽

Severely Obese ◽

Obese Subjects ◽

Vitro Model

Exercise improves insulin sensitivity and oxidative capacity in skeletal muscles. However, the effect of exercise on substrate oxidation is less clear in obese and type 2 diabetic subjects than in lean subjects. We investigated glucose and lipid metabolism and gene expression after 48 h with low-frequency electrical pulse stimulation (EPS), as an in vitro model of exercise, in cultured myotubes established from lean nondiabetic subjects and severely obese subjects (BMI ≥ 40 kg/m2) with and without type 2 diabetes. EPS induced an increase in insulin sensitivity but did not improve lipid oxidation in myotubes from severely obese subjects. Thus, EPS-induced increases in insulin sensitivity and lipid oxidation were positively and negatively correlated to BMI of the subjects, respectively. EPS enhanced oxidative capacity of glucose in myotubes from all subjects. Furthermore, EPS reduced mRNA expression of slow fiber-type marker (MYH7) in myotubes from diabetic subjects; however, the protein expression of this marker was not significantly affected by EPS in either of the donor groups. On the contrary, mRNA levels of interleukin-6 (IL-6) and IL-8 were unaffected by EPS in myotubes from diabetic subjects, while IL-6 mRNA expression was increased in myotubes from nondiabetic subjects. EPS-stimulated mRNA expression levels of MYH7, IL-6, and IL-8 correlated negatively with subjects' HbA1c and/or fasting plasma glucose, suggesting an effect linked to the diabetic phenotype. Taken together, these data show that myotubes from different donor groups respond differently to EPS, suggesting that this effect may reflect the in vivo characteristics of the donor groups.

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Reduced myocardial mitochondrial oxidative capacity in heart transplant recipients with type 2 diabetes

Diabetologie und Stoffwechsel ◽

10.1055/s-0037-1601761 ◽

2017 ◽

Vol 12 (S 01) ◽

pp. S1-S84

Author(s):

D Scheiber ◽

T Jelenik ◽

P Horn ◽

HP Schultheiss ◽

D Lassner ◽

...

Keyword(s):

Type 2 Diabetes ◽

Heart Transplant ◽

Oxidative Capacity ◽

Transplant Recipients ◽

Mitochondrial Oxidative Capacity ◽

Heart Transplant Recipients

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Novel coumarin containing dithiocarbamate derivatives as potent α-glucosidase inhibitors for management of type 2 diabetes

Medicinal Chemistry ◽

10.2174/1573406416666200826101205 ◽

2020 ◽

Vol 16 ◽

Author(s):

Marjan Mollazadeh ◽

Maryam Mohammadi-Khanaposhtani ◽

Yousef Valizadeh ◽

Afsaneh Zonouzi ◽

Mohammad Ali Faramarzi ◽

...

Keyword(s):

Type 2 Diabetes ◽

Kinetic Study ◽

Active Site ◽

Docking Study ◽

Secondary Amines ◽

Molecular Docking Study ◽

Glucosidase Inhibitors ◽

Dithiocarbamate Derivatives

Background: α-Glucosidase is a hydrolyze enzyme that plays a crucial role in degradation of carbohydrates and starch to glucose. Hence, α-glucosidase is an important target in the carbohydrate mediated diseases such as diabetes mellitus. Objective: In this study, novel coumarin containing dithiocarbamate derivatives 4a-n were synthesized and evaluated against α-glucosidase in vitro and in silico. Methods: These compounds were obtained of reaction between 4-(bromomethyl)-7-methoxy-2H-chromen-2-one 1, carbon disulfide 2, and primary or secondary amines 3a-n in the presence potassium hydroxide and ethanol at room temperature. In vitro α-glucosidase inhibition and kinetic study of these compounds were performed. Furthermore, docking study of the most potent compounds was also performed by Auto Dock Tools (version 1.5.6). Results: Obtained results showed that all the synthesized compounds exhibited prominent inhibitory activities (IC50 = 85.0 ± 4.0-566.6 ± 8.6 μM) in comparison to acarbose as standard inhibitor (IC50 = 750.0 ± 9.0 µM). Among them, secondary amine derivative 4d with pendant indole group was the most potent inhibitor. Enzyme kinetic study of the compound 4d revealed that this compound compete with substrate to connect to the active site of α-glucosidase and therefore is a competitive inhibitor. Also, molecular docking study predicted that this compound as well interacted with α-glucosidase active site pocket. Conclusion: Our results suggest that the coumarin-dithiocarbamate scaffold can be a promising lead structure for design potent α-glucosidase inhibitors for treatment of type 2 diabetes.

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Experimental Type 2 Diabetes Differently Impacts on the Select Functions of Bone Marrow-Derived Multipotent Stromal Cells

Cells ◽

10.3390/cells10020268 ◽

2021 ◽

Vol 10 (2) ◽

pp. 268

Author(s):

Jonathan Ribot ◽

Cyprien Denoeud ◽

Guilhem Frescaline ◽

Rebecca Landon ◽

Hervé Petite ◽

...

Keyword(s):

Type 2 Diabetes ◽

Bone Marrow ◽

Stromal Cells ◽

Adipogenic Differentiation ◽

Therapeutic Modality ◽

Multipotent Stromal Cells ◽

Cell Therapies

Bone marrow-derived multipotent stromal cells (BMMSCs) represent an attractive therapeutic modality for cell therapy in type 2 diabetes mellitus (T2DM)-associated complications. T2DM changes the bone marrow environment; however, its effects on BMMSC properties remain unclear. The present study aimed at investigating select functions and differentiation of BMMSCs harvested from the T2DM microenvironment as potential candidates for regenerative medicine. BMMSCs were obtained from Zucker diabetic fatty (ZDF; an obese-T2DM model) rats and their lean littermates (ZL; controls), and cultured under normoglycemic conditions. The BMMSCs derived from ZDF animals were fewer in number, with limited clonogenicity (by 2-fold), adhesion (by 2.9-fold), proliferation (by 50%), migration capability (by 25%), and increased apoptosis rate (by 2.5-fold) compared to their ZL counterparts. Compared to the cultured ZL-BMMSCs, the ZDF-BMMSCs exhibited (i) enhanced adipogenic differentiation (increased number of lipid droplets by 2-fold; upregulation of the Pparg, AdipoQ, and Fabp genes), possibly due to having been primed to undergo such differentiation in vivo prior to cell isolation, and (ii) different angiogenesis-related gene expression in vitro and decreased proangiogenic potential after transplantation in nude mice. These results provided evidence that the T2DM environment impairs BMMSC expansion and select functions pertinent to their efficacy when used in autologous cell therapies.

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Identifying Phenotypically Distinct Fibroblast Subsets in Type 2 Diabetes–Associated Iatrogenic Laryngotracheal Stenosis

Otolaryngology ◽

10.1177/01945998211014790 ◽

2021 ◽

pp. 019459982110147

Author(s):

Ioan A. Lina ◽

Alexandra Berges ◽

Rafael Ospino ◽

Ruth J. Davis ◽

Kevin M. Motz ◽

...

Keyword(s):

Type 2 Diabetes ◽

Flow Cytometry ◽

Pearson Correlation ◽

Phenotypic Expression ◽

In Vitro Study ◽

Cell Protein ◽

Laryngotracheal Stenosis ◽

Tertiary Referral Center

Objective Iatrogenic laryngotracheal stenosis (iLTS) is the pathologic narrowing of the glottis, subglottis, and/or trachea secondary to intubation or tracheostomy related injury. Patients with type 2 diabetes mellitus (T2DM) are more likely to develop iLTS. To date, the metabolomics and phenotypic expression of cell markers in fibroblasts derived from patients with T2DM and iLTS are largely unknown. Study Design Controlled in vitro cohort study. Setting Tertiary referral center (2017-2020). Methods This in vitro study assessed samples from 6 patients with iLTS who underwent surgery at a single institution. Fibroblasts were isolated from biopsy specimens of laryngotracheal scar and normal-appearing trachea and compared with controls obtained from the trachea of rapid autopsy specimens. Patients with iLTS were subcategorized into those with and without T2DM. Metabolic substrates were identified by mass spectrometry, and cell protein expression was measured by flow cytometry. Results T2DM iLTS-scar fibroblasts had a metabolically distinct profile and clustered tightly on a Pearson correlation heat map as compared with non-T2DM iLTS-scar fibroblasts. Levels of itaconate were elevated in T2DM iLTS-scar fibroblasts. Flow cytometry demonstrated that T2DM iLTS-scar fibroblasts were associated with higher CD90 expression (Thy-1; mean, 95%) when compared with non-T2DM iLTS-scar (mean, 83.6%; P = .0109) or normal tracheal fibroblasts (mean, 81.1%; P = .0042). Conclusions Scar-derived fibroblasts from patients with T2DM and iLTS have a metabolically distinct profile. These fibroblasts are characterized by an increase in itaconate, a metabolite related to immune-induced scar remodeling, and can be identified by elevated expression of CD90 (Thy-1) in vitro.

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PAR-4/Ca2+-calpain pathway activation stimulates platelet-derived microparticles in hyperglycemic type 2 diabetes

Cardiovascular Diabetology ◽

10.1186/s12933-021-01267-w ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Alessandra Giannella ◽

Giulio Ceolotto ◽

Claudia Maria Radu ◽

Arianna Cattelan ◽

Elisabetta Iori ◽

...

Keyword(s):

Type 2 Diabetes ◽

Normal Glucose Tolerance ◽

Calpain Inhibitor ◽

Pathway Activation ◽

Normal Glucose ◽

Circulating Levels ◽

Dependent Mechanism

Abstract Background Patients with type 2 diabetes (T2DM) have a prothrombotic state that needs to be fully clarified; microparticles (MPs) have emerged as mediators and markers of this condition. Thus, we investigate, in vivo, in T2DM either with good (HbA1c ≤ 7.0%; GGC) or poor (HbA1c > 7.0%; PGC) glycemic control, the circulating levels of MPs, and in vitro, the molecular pathways involved in the release of MPs from platelets (PMP) and tested their pro-inflammatory effects on THP-1 transformed macrophages. Methods In 59 T2DM, and 23 control subjects with normal glucose tolerance (NGT), circulating levels of CD62E+, CD62P+, CD142+, CD45+ MPs were determined by flow cytometry, while plasma levels of ICAM-1, VCAM-1, IL-6 by ELISA. In vitro, PMP release and activation of isolated platelets from GGC and PGC were investigated, along with their effect on IL-6 secretion in THP-1 transformed macrophages. Results We found that MPs CD62P+ (PMP) and CD142+ (tissue factor-bearing MP) were significantly higher in PGC T2DM than GGC T2DM and NGT. Among MPs, PMP were also correlated with HbA1c and IL-6. In vitro, we showed that acute thrombin exposure stimulated a significantly higher PMP release in PGC T2DM than GGC T2DM through a more robust activation of PAR-4 receptor than PAR-1 receptor. Treatment with PAR-4 agonist induced an increased release of PMP in PGC with a Ca2+-calpain dependent mechanism since this effect was blunted by calpain inhibitor. Finally, the uptake of PMP derived from PAR-4 treated PGC platelets into THP-1 transformed macrophages promoted a marked increase of IL-6 release compared to PMP derived from GGC through the activation of the NF-kB pathway. Conclusions These results identify PAR-4 as a mediator of platelet activation, microparticle release, and inflammation, in poorly controlled T2DM.

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