Skeletal Muscle Extracellular Vesicles Regulate Endothelial Cells in a Fiber Type Dependent Manner

Background : Peripheral arterial disease (PAD) is a disorder characterized by impaired blood flow to the legs and maladaptive changes in the skeletal muscle. It is generally accepted that the skeletal muscle characteristics in patients with PAD include decreased capillary density and an altered percentage of oxidative myofibers. The scientific literature is conflicting, and it is based on studies with small sample size and older methodologies of skeletal muscle analysis. In addition, women are under-represented or not included at all in these studies. Hypothesis : We hypothesized that there would be differences in skeletal muscle composition in PAD patients compared to healthy controls. We further hypothesized that there would be gender differences in skeletal muscle composition in PAD patients versus healthy controls. Methods : Thirty -one patients with PAD and 31 age-, gender-, and activity-matched healthy controls underwent gastrocnemius muscle biopsy. Capillary density analysis and muscle fiber type determination were performed using immunohistochemistry techniques. Capillary density was measured as endothelial cells per muscle fiber and endothelial cells per area (mm 2 ). Results : There was no significant difference in capillary density in patients with PAD versus healthy controls when measured as endothelial cells per fiber (mean = 1.45 ± 0.43 vs. 1.50 ± 0.35, NS) or area (mean = 1.20 ± 0.29 vs. 1.29 ± 0.33, NS). There was also no difference in muscle fiber type composition between the groups. In the PAD cohort, capillary density was significantly lower in the men versus the women (mean = 1.36 ± 0.35 vs. 1.59 ± 0.51, p=0.005). In our cohort of women, there was no difference in capillary density in patients with PAD versus healthy controls (N=12). In men, capillary density was significantly lower in the PAD group versus healthy controls (N=19, mean = 1.09 ± 0.20 vs. 1.28 ± 0.34, p=0.043). Conclusions : Our data fail to confirm the belief that patients with PAD have a decreased capillary density and an altered percentage of oxidative myofibers. However, we did find that gender has an important impact on these characteristics. Further study of skeletal muscle composition in PAD may help to better understand the functional relevance of the gender differences.

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HIV-Nef Protein Transfer to Endothelial Cells Requires Rac1 Activation and Leads to Endothelial Dysfunction Implications for Statin Treatment in HIV Patients

Circulation Research ◽

10.1161/circresaha.119.315082 ◽

2019 ◽

Vol 125 (9) ◽

pp. 805-820 ◽

Cited By ~ 5

Author(s):

Sarvesh Chelvanambi ◽

Samir K. Gupta ◽

Xingjuan Chen ◽

Bradley W. Ellis ◽

Bernhard F. Maier ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Endothelial Cells ◽

Antiretroviral Therapy ◽

Cardiovascular Diseases ◽

Extracellular Vesicles ◽

Reactive Oxygen ◽

Statin Treatment ◽

Dependent Manner ◽

Oxygen Species ◽

Hiv Patients

Rationale: Even in antiretroviral therapy-treated patients, HIV continues to play a pathogenic role in cardiovascular diseases. A possible cofactor may be persistence of the early HIV response gene Nef, which we have demonstrated recently to persist in the lungs of HIV+ patients on antiretroviral therapy. Previously, we have reported that HIV strains with Nef, but not Nef-deleted HIV strains, cause endothelial proinflammatory activation and apoptosis. Objective: To characterize mechanisms through which HIV-Nef leads to the development of cardiovascular diseases using ex vivo tissue culture approaches as well as interventional experiments in transgenic murine models. Methods and Results: Extracellular vesicles derived from both peripheral blood mononuclear cells and plasma from HIV+ patient blood samples induced human coronary artery endothelial cells dysfunction. Plasma-derived extracellular vesicles from antiretroviral therapy+ patients who were HIV-Nef+ induced significantly greater endothelial apoptosis compared with HIV-Nef-plasma extracellular vesicles. Both HIV-Nef expressing T cells and HIV-Nef-induced extracellular vesicles increased transfer of cytosol and Nef protein to endothelial monolayers in a Rac1-dependent manner, consequently leading to endothelial adhesion protein upregulation and apoptosis. HIV-Nef induced Rac1 activation also led to dsDNA breaks in endothelial colony forming cells, thereby resulting in endothelial colony forming cell premature senescence and endothelial nitric oxide synthase downregulation. These Rac1-dependent activities were characterized by NOX2-mediated reactive oxygen species production. Statin treatment equally inhibited Rac1 inhibition in preventing or reversing all HIV-Nef-induction abnormalities assessed. This was likely because of the ability of statins to block Rac1 prenylation as geranylgeranyl transferase inhibitors were effective in inhibiting HIV-Nef-induced reactive oxygen species formation. Finally, transgenic expression of HIV-Nef in endothelial cells in a murine model impaired endothelium-mediated aortic ring dilation, which was then reversed by 3-week treatment with 5 mg/kg atorvastatin. Conclusions: These studies establish a mechanism by which HIV-Nef persistence despite antiretroviral therapy could contribute to ongoing HIV-related vascular dysfunction, which may then be ameliorated by statin treatment.

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IL-6 and epinephrine have divergent fiber type effects on intramuscular lipolysis

Journal of Applied Physiology ◽

10.1152/japplphysiol.00558.2013 ◽

2013 ◽

Vol 115 (10) ◽

pp. 1457-1463 ◽

Cited By ~ 7

Author(s):

Tara L. MacDonald ◽

Zhongxiao Wan ◽

Scott Frendo-Cumbo ◽

David J. Dyck ◽

David C. Wright

Keyword(s):

Skeletal Muscle ◽

Soleus Muscle ◽

Ex Vivo ◽

Fiber Type ◽

Dependent Manner ◽

Glycerol Release ◽

Slow Twitch Muscle ◽

Murine Skeletal Muscle ◽

Amp Activated Protein Kinase ◽

Fast Twitch

IL-6 is an exercise-regulated myokine that has been suggested to increase lipolysis in fast-twitch skeletal muscle. However, it is not known if a similar effect is present in slow-twitch muscle. Furthermore, epinephrine increases IL-6 secretion from skeletal muscle, suggesting that IL-6 could play a role in mediating the lipolytic effects of catecholamines. The purpose of this study was to determine whether IL-6 stimulates skeletal muscle lipolysis in a fiber type dependent manner and is required for epinephrine-stimulated lipolysis in murine skeletal muscle. Soleus and extensor digitorum longus (EDL) muscles from male C57BL/6J wild-type and IL-6−/− mice were incubated with 1 μM (183 ng/ml) epinephrine or 75 ng/ml recombinant IL-6 (rIL-6) for 60 min. IL-6 treatment increased 5′-AMP-activated protein kinase and signal transducer and activator of transcription 3 phosphorylation and glycerol release in isolated EDL but not soleus muscles from C57BL/6J mice. Conversely, epinephrine increased glycerol release in soleus but not EDL muscles from C57BL/6J mice. Basal lipolysis was elevated in soleus muscle from IL-6−/− mice, and this was associated with increases in adipose triglyceride lipase (ATGL) and its coactivator comparative gene identification-58 (CGI-58). The increase in ATGL content does not appear to be due to a loss of IL-6's direct effects, because ex vivo treatment with IL-6 failed to alter the expression of ATGL mRNA in soleus muscle. In summary, IL-6 stimulates lipolysis in glycolytic but not oxidative muscle, whereas the opposite fiber type effect is seen with epinephrine. The absence of IL-6 indirectly upregulates lipolysis, and this is associated with increases in ATGL and its coactivator CGI-58.

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High-fat diet induces skeletal muscle oxidative stress in a fiber type-dependent manner in rats

Free Radical Biology and Medicine ◽

10.1016/j.freeradbiomed.2017.07.005 ◽

2017 ◽

Vol 110 ◽

pp. 381-389 ◽

Cited By ~ 17

Author(s):

Ricardo A. Pinho ◽

Diane M. Sepa-Kishi ◽

George Bikopoulos ◽

Michelle V. Wu ◽

Abinas Uthayakumar ◽

...

Keyword(s):

Oxidative Stress ◽

Skeletal Muscle ◽

High Fat Diet ◽

Fiber Type ◽

Dependent Manner ◽

High Fat

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Diet-induced obesity and acute hyperlipidemia reduce IκBα levels in rat skeletal muscle in a fiber-type dependent manner

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00097.2005 ◽

2006 ◽

Vol 290 (1) ◽

pp. R233-R240 ◽

Cited By ~ 33

Author(s):

Bankim A. Bhatt ◽

John J. Dube ◽

Nikolas Dedousis ◽

Jodie A. Reider ◽

Robert M. O’Doherty

Keyword(s):

Skeletal Muscle ◽

P38 Mapk ◽

Fiber Type ◽

Dependent Manner ◽

Rat Skeletal Muscle ◽

Diet Induced Obesity ◽

Slow Twitch ◽

Fast Twitch ◽

Fat Feeding ◽

Increased Activity

Increased activity of proinflammatory/stress pathways has been implicated in the pathogenesis of insulin resistance in obesity. However, the effects of obesity on the activity of these pathways in skeletal muscle, the major insulin-sensitive tissue by mass, are poorly understood. Furthermore, the mechanisms that activate proinflammatory/stress pathways in obesity are unknown. The present study addressed the effects of diet-induced obesity (DIO; 6 wk of high-fat feeding) and acute (6-h) hyperlipidemia (HL) in rats on activity of IKK/IκB/NF-κB c-Jun NH2-terminal kinase, and p38 MAPK in three skeletal muscles differing in fiber type [superficial vastus (Vas; fast twitch-glycolytic), soleus (Sol; slow twitch-oxidative), and gastrocnemius (Gas; mixed)]. DIO decreased the levels of the IκBα in Vas (24 ± 3%, P = 0.001, n = 8) but not in Sol or Gas compared with standard chow-fed controls. Similar to DIO, HL decreased IκBα levels in Vas (26 ± 5%, P = 0.006, n = 6) and in Gas (15 ± 4%, P = 0.01, n = 7) but not in Sol compared with saline-infused controls. Importantly, the fiber-type-dependent effects on IκBα levels could not be explained by differential accumulation of triglyceride in Sol and Vas. HL, but not DIO, decreased phospho-p38 MAPK levels in Vas (41 ± 7% P = 0.004, n = 6) but not in Sol or Gas. Finally, skeletal muscle c-Jun NH2-terminal kinase activity was unchanged by DIO or HL. We conclude that diet-induced obesity and acute HL reduce IκBα levels in rat skeletal muscle in a fiber-type-dependent manner.

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Live tracking of inter-organ communication by endogenous exosomes in vivo

10.1101/380311 ◽

2018 ◽

Cited By ~ 3

Author(s):

Frederik J Verweij ◽

Celine Revenu ◽

Guillaume Arras ◽

Florent Dingli ◽

Damarys Loew ◽

...

Keyword(s):

Endothelial Cells ◽

Extracellular Vesicles ◽

Molecular Mechanisms ◽

Scavenger Receptor ◽

Model Organisms ◽

Zebrafish Embryos ◽

List Type ◽

Dependent Manner ◽

Fluorescent Reporter

SUMMARYExtracellular vesicles (EVs) are released by most cell types but the definitive demonstration of their functional relevance remains challenging due to the lack of appropriate model organisms. Here we developed anin vivomodel to study EV physiology by expressing CD63-pHluorin in zebrafish embryos. A combination of microscopy techniques and proteomic analysis allowed us to study the biogenesis, composition, transfer, uptake and fate of individual endogenous EVsin vivo. We identified an exosome population released in a syntenin-dependent manner from the Yolk Syncytial Layer into the blood circulation. These exosomes were specifically captured, endocytosed and degraded by patrolling macrophages and endothelial cells in the Caudal Vein Plexus (CVP) in a scavenger receptor and dynamin-dependent manner. Interference with exosome secretion affected CVP growth, supporting their trophic role. Altogether, our work provides a unique model to track in vivo inter-organ communication by endogenous exosomes at individual vesicle level and high spatio-temporal accuracy.Highlights- Single endogenous EVs can be live-visualized in the whole embryo with CD63-pHluorin- In the YSL, syntenin regulates exosome release into the blood for their propagation- YSL exosomes reach the tail to be taken up by macrophages and endothelial cells- Uptake is scavenger receptor and dynamin-dependent and provides trophic supportBlurbWe propose zebrafish embryos expressing a fluorescent reporter for exosomes as a relevant model organism to live-track production, journey and fate of individual extracellular vesicles in vivo. Our model allows investigation of the composition of EVs and the molecular mechanisms controlling their biogenesis and fate and functions in receiving cells.

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Acute Succinate Administration Increases Oxidative Phosphorylation and Skeletal Muscle Explosive Strength via SUCNR1

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.808863 ◽

2022 ◽

Vol 8 ◽

Author(s):

Guli Xu ◽

Yexian Yuan ◽

Pei Luo ◽

Jinping Yang ◽

Jingjing Zhou ◽

...

Keyword(s):

Skeletal Muscle ◽

Oxidative Phosphorylation ◽

Fiber Type ◽

Muscle Metabolism ◽

Acute Effect ◽

C2c12 Cells ◽

Dependent Manner ◽

Mitochondrial Complex ◽

Explosive Strength ◽

Acute Injection

Endurance training and explosive strength training, with different contraction protein and energy metabolism adaptation in skeletal muscle, are both beneficial for physical function and quality of life. Our previous study found that chronic succinate feeding enhanced the endurance exercise of mice by inducing skeletal muscle fiber-type transformation. The purpose of this study is to investigate the effect of acute succinate administration on skeletal muscle explosive strength and its potential mechanism. Succinate was injected to mature mice to explore the acute effect of succinate on skeletal muscle explosive strength. And C2C12 cells were used to verify the short-term effect of succinate on oxidative phosphorylation. Then the cells interfered with succinate receptor 1 (SUCNR1) siRNA, and the SUCNR1-GKO mouse model was used for verifying the role of SUCNR1 in succinate-induced muscle metabolism and expression and explosive strength. The results showed that acute injection of succinate remarkably improved the explosive strength in mice and also decreased the ratio of nicotinamide adenine dinucleotide (NADH) to NAD+ and increased the mitochondrial complex enzyme activity and creatine kinase (CK) activity in skeletal muscle tissue. Similarly, treatment of C2C12 cells with succinate revealed that succinate significantly enhanced oxidative phosphorylation with increased adenosine triphosphate (ATP) content, CK, and the activities of mitochondrial complex I and complex II, but with decreased lactate content, reactive oxygen species (ROS) content, and NADH/NAD+ ratio. Moreover, the succinate's effects on oxidative phosphorylation were blocked in SUCNR1-KD cells and SUCNR1-KO mice. In addition, succinate-induced explosive strength was also abolished by SUCNR1 knockout. All the results indicate that acute succinate administration increases oxidative phosphorylation and skeletal muscle explosive strength in a SUCNR1-dependent manner.

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Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050755 ◽

1974 ◽

Vol 32 ◽

pp. 148-149

Author(s):

D. E. Philpott ◽

A. Takahashi

Keyword(s):

Skeletal Muscle ◽

Endothelial Cells ◽

Salivary Gland ◽

Carotid Artery ◽

Basement Membrane ◽

Coronary Vessels ◽

Ruthenium Red ◽

E Coli ◽

Old Rats ◽

The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

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Natriuretic Peptides Regulate the Expression of Tissue Factor and PAI-1 in Endothelial Cells

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614861 ◽

1999 ◽

Vol 82 (11) ◽

pp. 1497-1503 ◽

Cited By ~ 20

Author(s):

Hajime Tsuji ◽

Hiromi Nishimura ◽

Haruchika Masuda ◽

Yasushi Kunieda ◽

Hidehiko Kawano ◽

...

Keyword(s):

Endothelial Cells ◽

Tissue Factor ◽

Plasminogen Activator ◽

Natriuretic Peptide ◽

Culture Media ◽

Tissue Type ◽

Dependent Manner ◽

Ang Ii ◽

Plasminogen Activator Inhibitor 1 ◽

Pai 1

SummaryIn the present study, we demonstrate that brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) interact with angiotensin II (Ang II) in regulative blood coagulation and fibrinolysis by suppressing the expressions of both tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) induced by Ang II. The expressions of TF and PAI-1 mRNA were analyzed by northern blotting methods, and the activities of TF on the surface of rat aortic endothelial cells (RAECs) and PAI-1 in the culture media were respectively measured by chromogenic assay.Both BNP and CNP suppressed the expressions of TF and PAI-1 mRNA induced by Ang II in a time- and concentration-dependent manner via cGMP cascade, which suppressions were accompanied by respective decrease in activities of TF and PAI-1. However, neither the expression of tissue factor pathway inhibitor (TFPI) nor tissue-type plasminogen activator (TPA) mRNA was affected by the treatment of BNP and CNP.

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Hemoglobin Enhances the Binding of Bacterial Endotoxin to Human Endothelial Cells

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650565 ◽

1996 ◽

Vol 76 (02) ◽

pp. 258-262 ◽

Cited By ~ 12

Author(s):

Robert I Roth

Keyword(s):

Endothelial Cells ◽

Binding Protein ◽

Bacterial Endotoxin ◽

Dependent Manner ◽

Serum Free Medium ◽

Free Medium ◽

Human Endothelial Cells ◽

Serum Factors ◽

Serum Free ◽

Lps Binding

SummaryHuman endothelial cells, when incubated with bacterial endotoxin (lipopolysaccharide, LPS), modify their surface in association with prominent production of procoagulant tissue factor (TF) activity. This deleterious biological effect of LPS has been shown previously to be enhanced approximately 10-fold by the presence of hemoglobin (Hb), a recently recognized LPS binding protein that causes disaggregation of LPS and increases the biological activity of LPS in a number of in vitro assays. The present study was performed to test the hypothesis that Hb enhances the LPS-induced procoagulant activity of human umbilical vein endothelial cells (HUVEC) by increasing LPS binding to the cells. The binding of 3H-LPS to HUVEC was determined in the absence or presence of Hb or two other known LPS-binding proteins, human serum albumin (HSA) and IgG. LPS binding was substantially increased in the presence of Hb, in a Hb concentration-dependent manner, but was not increased by HSA or IgG. Hb enhancement of LPS binding was observed in serum-free medium, indicating that there was no additional requirement for any of the serum factors known to participate in the interaction of LPS with cells (e.g., lipopolysaccharide (LPS)-binding protein (LBP) and soluble CD14 (sCD14)). Hb enhancement of LPS binding also was observed in the more physiologic condition of 100% plasma. LPS-induced TF activity was stimulated by Hb, but not by HSA or IgG. In serum-free medium, TF activity was not stimulated under any of the conditions tested. Ultrafiltration of LPS was dramatically increased after incubation with Hb but not with HSA or IgG, suggesting that LPS disaggregation by Hb was responsible for the enhanced binding of LPS to HUVEC and the subsequent stimulation of TF activity.

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