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1.
Metabolites ; 12(9)2022 Aug 27.
Article in English | MEDLINE | ID: mdl-36144205

ABSTRACT

Burn injury remains a significant public health issue worldwide. Metabolic derangements are a major complication of burn injury and negatively affect the clinical outcomes of severely burned patients. These metabolic aberrations include muscle wasting, hypermetabolism, hyperglycemia, hyperlactatemia, insulin resistance, and mitochondrial dysfunction. However, little is known about the impact of burn injury on the metabolome profile in skeletal muscle. We have previously shown that farnesyltransferase inhibitor (FTI) reverses burn injury-induced insulin resistance, mitochondrial dysfunction, and the Warburg effect in mouse skeletal muscle. To evaluate metabolome composition, targeted quantitative analysis was performed using capillary electrophoresis mass spectrometry in mouse skeletal muscle. Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and hierarchical cluster analysis demonstrated that burn injury induced a global change in metabolome composition. FTI treatment almost completely prevented burn injury-induced alterations in metabolite levels. Pathway analysis revealed that the pathways most affected by burn injury were purine, glutathione, ß-alanine, glycine, serine, and threonine metabolism. Burn injury induced a suppressed oxidized to reduced nicotinamide adenine dinucleotide (NAD+/NADH) ratio as well as oxidative stress and adenosine triphosphate (ATP) depletion, all of which were reversed by FTI. Moreover, our data raise the possibility that burn injury may lead to increased glutaminolysis and reductive carboxylation in mouse skeletal muscle.

2.
Metabolites ; 12(7)2022 Jul 01.
Article in English | MEDLINE | ID: mdl-35888737

ABSTRACT

Mitochondrial dysfunction has been implicated in the pathogenesis of inflammation and multi-organ dysfunction in major trauma, including burn injury. Coenzyme Q10 (CoQ10) is a metabolite of the mevalonate pathway and an essential cofactor for the electron transport in the mitochondria. In addition, its reduced form (ubiquinol) functions as an antioxidant. Little is known as to whether oral CoQ10 supplementation effectively increases intracellular CoQ10 levels in humans. To study the bioavailability of CoQ10 supplementation, we conducted a randomized, double-blind, placebo-controlled study of reduced CoQ10 (ubiquinol-10) (1800 mg/day, t.i.d.) in burn patients at a single, tertiary-care hospital. Baseline plasma CoQ10 levels were significantly lower in burn patients than in healthy volunteers, although plasma CoQ10/cholesterol ratio did not differ between the groups. CoQ10 supplementation increased plasma concentrations of total and reduced CoQ10 and total CoQ10 content in peripheral blood mononuclear cells (PBMCs) in burn patients compared with the placebo group. CoQ10 supplementation did not significantly change circulating levels of mitochondrial DNA, inflammatory markers (e.g., interleukins, TNF-α, IFN-γ), or Sequential Organ Failure Assessment (SOFA) scores compared with the placebo group. This study showed that a relatively high dose of reduced CoQ10 supplementation increased the intracellular CoQ10 content in PBMCs as well as plasma concentrations in burn patients.

3.
Biochem Biophys Res Commun ; 556: 93-98, 2021 06 04.
Article in English | MEDLINE | ID: mdl-33845310

ABSTRACT

Sepsis remains a leading cause of mortality in critically ill patients and is characterized by multi-organ dysfunction. Mitochondrial damage has been proposed to be involved in the pathophysiology of sepsis. In addition to metabolic impairments resulting from mitochondrial dysfunction, mitochondrial DNA (mtDNA) causes systemic inflammation as a damage-associated molecular pattern when it is released to the circulation. Metabolic derangements in skeletal muscle are a major complication of sepsis and negatively affects clinical outcomes of septic patients. However, limited knowledge is available about sepsis-induced mitochondrial damage in skeletal muscle. Here, we show that sepsis induced profound abnormalities in cristae structure, rupture of the inner and outer membranes and enlargement of the mitochondria in mouse skeletal muscle in a time-dependent manner, which was associated with increased plasma mtDNA levels. Farnesyltransferase inhibitor, FTI-277, prevented sepsis-induced morphological aberrations of the mitochondria, and blocked the increased plasma mtDNA levels along with improved survival. These results indicate that protein farnesylation plays a role in sepsis-induced damage of the mitochondria in mouse skeletal muscle. Our findings suggest that mitochondrial disintegrity in skeletal muscle may contribute to elevated circulating mtDNA levels in sepsis.


Subject(s)
DNA, Mitochondrial/blood , Farnesyltranstransferase/antagonists & inhibitors , Mitochondria/drug effects , Muscle, Skeletal/drug effects , Protective Agents/pharmacology , Protective Agents/therapeutic use , Sepsis/drug therapy , Animals , Male , Methionine/analogs & derivatives , Methionine/pharmacology , Mice , Mitochondria/pathology , Muscle, Skeletal/pathology , Sepsis/blood , Sepsis/pathology , Time Factors
4.
Sci Adv ; 7(2)2021 01.
Article in English | MEDLINE | ID: mdl-33523984

ABSTRACT

Tuberous sclerosis complex (TSC) results from loss of a tumor suppressor gene - TSC1 or TSC2, encoding hamartin and tuberin, respectively. These proteins formed a complex to inhibit mTORC1-mediated cell growth and proliferation. Loss of either protein leads to overgrowth lesions in many vital organs. Gene therapy was evaluated in a mouse model of TSC2 using an adeno-associated virus (AAV) vector carrying the complementary for a "condensed" form of human tuberin (cTuberin). Functionality of cTuberin was verified in culture. A mouse model of TSC2 was generated by AAV-Cre recombinase disruption of Tsc2-floxed alleles at birth, leading to a shortened lifespan (mean 58 days) and brain pathology consistent with TSC. When these mice were injected intravenously on day 21 with AAV9-cTuberin, the mean survival was extended to 462 days with reduction in brain pathology. This demonstrates the potential of treating life-threatening TSC2 lesions with a single intravenous injection of AAV9-cTuberin.

5.
Am J Physiol Endocrinol Metab ; 320(1): E150-E159, 2021 01 01.
Article in English | MEDLINE | ID: mdl-33284091

ABSTRACT

Sepsis remains a leading cause of mortality in critically ill patients. Muscle wasting is a major complication of sepsis and negatively affects clinical outcomes. Despite intense investigation for many years, the molecular mechanisms underlying sepsis-related muscle wasting are not fully understood. In addition, a potential role of muscle wasting in disease development of sepsis has not been studied. Myostatin is a myokine that downregulates skeletal muscle mass. We studied the effects of myostatin deficiency on muscle wasting and other clinically relevant outcomes, including mortality and bacterial clearance, in mice. Myostatin deficiency prevented muscle atrophy along with inhibition of increases in muscle-specific RING finger protein 1 (MuRF-1) and atrogin-1 expression and phosphorylation of signal transducer and activator of transcription protein 3 (STAT3; major players of muscle wasting) in septic mice. Moreover, myostatin deficiency improved survival and bacterial clearance of septic mice. Sepsis-induced liver dysfunction, acute kidney injury, and neutrophil infiltration into the liver and kidney were consistently mitigated by myostatin deficiency, as indicated by plasma concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and neutrophil gelatinase-associated lipocalin (NGAL) and myeloperoxidase activity in the organs. Myostatin deficiency also inhibited sepsis-induced increases in plasma high-mobility group protein B1 (HMGB1) and macrophage inhibitory cytokine (MIC)-1/growth differentiation factor (GDF)-15 concentrations. These results indicate that myostatin plays an important role not only in muscle wasting but also in other clinically relevant outcomes in septic mice. Furthermore, our data raise the possibility that muscle wasting may not be simply a complication, but myostatin-mediated muscle cachexia and related changes in muscle may actually drive the development of sepsis as well.NEW & NOTEWORTHY Muscle wasting is a major complication of sepsis, but its role in the disease development is not known. Myostatin deficiency improved bacterial clearance and survival and mitigated damage in the liver and kidney in septic mice, which paralleled prevention of muscle wasting. These results raise the possibility that muscle wasting may not simply be a complication of sepsis, but myostatin-mediated cachexic changes may have a role in impaired bacterial clearance and mortality in septic mice.


Subject(s)
Muscular Atrophy/genetics , Myostatin/deficiency , Myostatin/genetics , Sepsis/genetics , Acute Kidney Injury/genetics , Animals , Cachexia/genetics , Cachexia/prevention & control , Lipocalin-2/blood , Liver Diseases/etiology , Liver Diseases/genetics , Liver Function Tests , Male , Mice , Muscle Proteins/biosynthesis , Muscle Proteins/genetics , Muscular Atrophy/prevention & control , Neutrophil Infiltration/genetics , Phosphorylation , STAT3 Transcription Factor/biosynthesis , STAT3 Transcription Factor/genetics , Sepsis/microbiology , Sepsis/mortality , Survival Analysis , Tripartite Motif Proteins/biosynthesis , Tripartite Motif Proteins/genetics , Ubiquitin-Protein Ligases/biosynthesis , Ubiquitin-Protein Ligases/genetics
7.
Elife ; 82019 12 03.
Article in English | MEDLINE | ID: mdl-31793435

ABSTRACT

Chronic critical illness is a global clinical issue affecting millions of sepsis survivors annually. Survivors report chronic skeletal muscle weakness and development of new functional limitations that persist for years. To delineate mechanisms of sepsis-induced chronic weakness, we first surpassed a critical barrier by establishing a murine model of sepsis with ICU-like interventions that allows for the study of survivors. We show that sepsis survivors have profound weakness for at least 1 month, even after recovery of muscle mass. Abnormal mitochondrial ultrastructure, impaired respiration and electron transport chain activities, and persistent protein oxidative damage were evident in the muscle of survivors. Our data suggest that sustained mitochondrial dysfunction, rather than atrophy alone, underlies chronic sepsis-induced muscle weakness. This study emphasizes that conventional efforts that aim to recover muscle quantity will likely remain ineffective for regaining strength and improving quality of life after sepsis until deficiencies in muscle quality are addressed.


Subject(s)
Mitochondrial Diseases/metabolism , Muscle Weakness/etiology , Muscle Weakness/metabolism , Muscle Weakness/pathology , Sepsis/complications , Animals , Atrophy/etiology , Atrophy/pathology , Disease Models, Animal , Female , Humans , Male , Mice , Mice, Inbred C57BL , Middle Aged , Mitochondria, Muscle/enzymology , Mitochondria, Muscle/metabolism , Mitochondrial Diseases/pathology , Muscle, Skeletal/metabolism , Muscle, Skeletal/pathology , Quality of Life
8.
FEBS Open Bio ; 9(2): 348-363, 2019 02.
Article in English | MEDLINE | ID: mdl-30761259

ABSTRACT

Mitochondrial dysfunction is associated with metabolic alterations in various disease states, including major trauma (e.g., burn injury). Metabolic derangements, including muscle insulin resistance and hyperlactatemia, are a clinically significant complication of major trauma. Coenzyme Q10 (CoQ10) is an essential cofactor for mitochondrial electron transport, and its reduced form acts as a lipophilic antioxidant. Here, we report that burn injury induces impaired muscle insulin signaling, hyperlactatemia, mitochondrial dysfunction (as indicated by suppressed mitochondrial oxygen consumption rates), morphological alterations of the mitochondria (e. g., enlargement, and loss of cristae structure), mitochondrial oxidative stress, and disruption of mitochondrial integrity (as reflected by increased mitochondrial DNA levels in the cytosol and circulation). All of these alterations were significantly alleviated by CoQ10 treatment compared with vehicle alone. These findings indicate that CoQ10 treatment is efficacious in protecting against mitochondrial dysfunction and insulin resistance in skeletal muscle of burned mice. Our data highlight CoQ10 as a potential new strategy to prevent mitochondrial damage and metabolic dysfunction in burn patients.


Subject(s)
Burns/metabolism , Insulin/metabolism , Mitochondria/metabolism , Muscle, Skeletal/metabolism , Signal Transduction , Ubiquinone/analogs & derivatives , Animals , Male , Mice , Ubiquinone/metabolism
9.
Free Radic Biol Med ; 131: 243-250, 2019 02 01.
Article in English | MEDLINE | ID: mdl-30529602

ABSTRACT

Delayed paraplegia complicates the recovery from spinal cord ischemia or traumatic spinal cord injury. While delayed motor neuron apoptosis is implicated in the pathogenesis, no effective treatment or preventive measures is available for delayed paraplegia. Hydrogen sulfide exerts anti-apoptotic effects. Here, we examined effects of hydrogen sulfide breathing on the recovery from transient spinal cord ischemia. Breathing hydrogen sulfide starting 23 h after reperfusion for 5 h prevented delayed paraplegia after 5 min of spinal cord ischemia. Beneficial effects of hydrogen sulfide were mediated by upregulation of anti-apoptotic Bcl-XL and abolished by nitric oxide synthase 2 deficiency. S-nitrosylation of NFkB p65 subunit, which is induced by nitric oxide derived from nitric oxide synthase 2, facilitated subsequent sulfide-induced persulfidation of p65 and transcription of anti-apoptotic genes. These results uncover the molecular mechanism of the anti-apoptotic effects of sulfide based on the interaction between nitric oxide and sulfide. Exploitation of the anti-apoptotic effects of delayed hydrogen sulfide breathing may provide a new therapeutic approach for delayed paraplegia.


Subject(s)
Hydrogen Sulfide/pharmacology , Neuroprotective Agents/pharmacology , Nitric Oxide Synthase Type II/genetics , Paraplegia/prevention & control , Reperfusion Injury/drug therapy , Spinal Cord Ischemia/drug therapy , Administration, Inhalation , Animals , Apoptosis/drug effects , Apoptosis/genetics , Cell Line, Tumor , Gene Expression Regulation , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Neurons/drug effects , Neurons/metabolism , Neurons/pathology , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/deficiency , Paraplegia/genetics , Paraplegia/metabolism , Paraplegia/pathology , Reperfusion Injury/genetics , Reperfusion Injury/metabolism , Reperfusion Injury/pathology , Signal Transduction , Spinal Cord Ischemia/genetics , Spinal Cord Ischemia/metabolism , Spinal Cord Ischemia/pathology , Transcription Factor RelA/genetics , Transcription Factor RelA/metabolism , bcl-X Protein/genetics , bcl-X Protein/metabolism
10.
Biochem Biophys Res Commun ; 501(4): 893-897, 2018 07 02.
Article in English | MEDLINE | ID: mdl-29763605

ABSTRACT

Previous studies have shown that androgenic alopecia is associated with metabolic syndrome and diabetes. However, the detailed mechanism whereby diabetes causes alopecia still remains unclear. We focused on the inflammatory response that is caused by diabetes or obesity, given that inflammation is a risk factor for hair loss. Inducible nitric oxide synthase (iNOS) is known to be upregulated under conditions of acute or chronic inflammation. To clarify the potential role of iNOS in diabetes-related alopecia, we generated obese diabetic iNOS-deficient (ob/ob; iNOS-KO mice). We observed that ob/ob; iNOS-KO mice were potentiated for the transition from telogen (rest phase) to anagen (growth phase) in the hair cycle compared with iNOS-proficient ob/ob mice. To determine the effect of nitric oxide (NO) on the hair cycle, we administered an iNOS inhibitor intraperitoneally (compound 1400 W, 10 mg/kg) or topically (10% aminoguanidine) in ob/ob mice. We observed that iNOS inhibitors promoted anagen transition in ob/ob mice. Next, we administered an NO donor (S-nitrosoglutathione, GSNO), to test whether NO has the telogen elongation effects. The NO donor was sufficient to induce telogen elongation in wild-type mice. Together, our data indicate that iNOS-derived NO plays a role in telogen elongation under the inflammatory conditions associated with diabetes in mice.


Subject(s)
Diabetes Mellitus, Experimental/enzymology , Diabetes Mellitus, Experimental/physiopathology , Hair/physiopathology , Nitric Oxide Synthase Type II/metabolism , Obesity/physiopathology , Regeneration , Administration, Topical , Animals , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/pharmacology , Hair/drug effects , Hair/enzymology , Hair/growth & development , Injections, Intraperitoneal , Male , Mice, Inbred C57BL , Mice, Knockout , Mice, Obese , Nitric Oxide Synthase Type II/antagonists & inhibitors , RNA, Messenger/genetics , RNA, Messenger/metabolism , Regeneration/drug effects , S-Nitrosoglutathione/metabolism
11.
Exp Ther Med ; 15(2): 1314-1320, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29434718

ABSTRACT

Highly active antiretroviral therapy (HAART) has successfully reduced the mortality rate of patients with human immune deficiency virus (HIV) and HIV protease inhibitors (HIV PIs) are key components of HAART. Complications of HAART, particularly those associated with HIV PIs including lipodystrophy and metabolic disturbance, have emerged as an important public health issue. No specific treatment is available to prevent and/or treat HIV PI-associated lipodystrophy and metabolic syndrome. The present study demonstrated that a relatively low-dose of farnesyltransferase inhibitor (FTI), tipifarnib (3 mg/kg/day, subcutaneous injection) and lonafarnib (5 mg/kg/day, subcutaneous injection), prevented the onset of lipodystrophy and metabolic syndrome induced by the combination of two HIV PIs, lopinavir (50 mg/kg/day, intraperitoneal injection) and ritonavir (12.5 mg/kg/day, intraperitoneal injection), in mice. Consistent with previous studies, treatment with lopinavir/ritonavir for 2 weeks decreased body weight, adipose tissue mass, levels of plasma adiponectin and leptin, and increased plasma levels of triglycerides, total cholesterol and insulin. Tipifarnib and lonafarnb prevented or ameliorated all of these alterations in the HIV PI-treated mice. These data identify FTIs as a novel potential strategy to prevent or treat HIV PI-associated lipodystrophy and metabolic syndrome in HIV-infected patients on HAART.

12.
Sci Rep ; 7(1): 12653, 2017 10 04.
Article in English | MEDLINE | ID: mdl-28978999

ABSTRACT

This study aimed to establish a therapeutic strategy targeting hypoxic cancer cells in gastric carcinoma (GC). YC-1 is a HIF-1α inhibitor, and we revealed that low-dose YC-1 (10 µM) suppressed HIF-1α expression, and induced hypoxia-dependent apoptosis in the GC cell line 58As9. This hypoxia-specific apoptosis induction by YC-1 involved excessive reactive oxygen species (ROS) generation. The apoptotic effect of 10 µM YC-1 was enhanced by additional glucose (G) and insulin (I) treatments. RT-PCR demonstrated that 10 µM YC-1 reduced hypoxia-induced expression of HIF-1α targets involved in anaerobic glycolysis. Metabolic analysis showed that YC-1 shifted glucose metabolism in hypoxic cells from anaerobic glycolysis to oxidative phosphorylation (OXPHOS). Additional GI accelerated membranous GLUT1 translocation, elevating glucose uptake, and increased acetyl-CoA levels, leading to more ROS generation in hypoxic YC-1-treated cells. Finally, we evaluated the anti-cancer effect of low-dose YC-1 (1 mg/kg) + G (2 g/kg) and I (1 unit/3 g G) treatment in xenograft models. YC-1 + GI therapy strongly inhibited tumour growth. Immunohistochemical analysis demonstrated that YC-1 + GI reduced HIF-1α expression and pimonidazole accumulation in tumours. Conversely, YC-1 + GI increased intra-tumoral 8-OHdG and levels of apoptosis markers. Low-dose YC-1 + GI is a unique therapy targeting hypoxic GC cells that generates lethal ROS via forced activation of OXPHOS.


Subject(s)
Carcinoma/drug therapy , Glucose Transporter Type 1/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Indazoles/administration & dosage , Stomach Neoplasms/drug therapy , 8-Hydroxy-2'-Deoxyguanosine , Acetyl Coenzyme A/genetics , Anaerobiosis/drug effects , Animals , Apoptosis/drug effects , Carcinoma/metabolism , Carcinoma/pathology , Cell Line, Tumor , Deoxyguanosine/administration & dosage , Deoxyguanosine/analogs & derivatives , Glucose/metabolism , Glycolysis/drug effects , Humans , Insulin/metabolism , Mice , Nitroimidazoles/administration & dosage , Oxidative Phosphorylation/drug effects , Stomach Neoplasms/metabolism , Stomach Neoplasms/pathology , Tumor Hypoxia , Xenograft Model Antitumor Assays
13.
Shock ; 48(4): 387-389, 2017 10.
Article in English | MEDLINE | ID: mdl-28915213
14.
Sci Rep ; 7(1): 6618, 2017 07 26.
Article in English | MEDLINE | ID: mdl-28747716

ABSTRACT

Metabolic derangements are a clinically significant complication of major trauma (e.g., burn injury) and include various aspects of metabolism, such as insulin resistance, muscle wasting, mitochondrial dysfunction and hyperlactatemia. Nonetheless, the molecular pathogenesis and the relation between these diverse metabolic alterations are poorly understood. We have previously shown that burn increases farnesyltransferase (FTase) expression and protein farnesylation and that FTase inhibitor (FTI) prevents burn-induced hyperlactatemia, insulin resistance, and increased proteolysis in mouse skeletal muscle. In this study, we found that burn injury activated mTORC1 and hypoxia-inducible factor (HIF)-1α, which paralleled dysfunction, morphological alterations (i.e., enlargement, partial loss of cristae structure) and impairment of respiratory supercomplex assembly of the mitochondria, and ER stress. FTI reversed or ameliorated all of these alterations in burned mice. These findings indicate that these burn-induced changes, which encompass various aspects of metabolism, may be linked to one another and require protein farnesylation. Our results provide evidence of involvement of the mTORC1-HIF-1α pathway in burn-induced metabolic derangements. Our study identifies protein farnesylation as a potential hub of the signaling network affecting multiple aspects of metabolic alterations after burn injury and as a novel potential molecular target to improve the clinical outcome of severely burned patients.


Subject(s)
Burns/pathology , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Mechanistic Target of Rapamycin Complex 1/metabolism , Mitochondria/metabolism , Muscles/pathology , Protein Prenylation , Animals , Disease Models, Animal , Electron Transport Chain Complex Proteins/metabolism , Endoplasmic Reticulum Stress , Metabolic Networks and Pathways , Mice, Inbred C57BL , Protein Multimerization
15.
Shock ; 48(6): 600-609, 2017 12.
Article in English | MEDLINE | ID: mdl-28520694

ABSTRACT

Despite several decades of focused investigation, sepsis remains a major cause of mortality in critically ill patients. Advancements in intensive care have enabled more patients to survive the acute phase of sepsis than previously, but a growing number of them progress to chronic critical illness. The failure of previous randomized clinical trials of anti-inflammatory agents to show any pro-survival benefit in septic patients underscores current thought that simple anti-inflammatory strategies are ineffective because the inhibitory effect of anti-inflammatory agents undermines the immune response to pathogens. New strategies with the dual capability of ameliorating inflammation in organs while stimulating antimicrobial activity are eagerly awaited. On the other hand, the metabolic alterations associated with systemic inflammatory response, including mitochondrial dysfunction and metabolic shift, are closely linked through a nexus of signaling pathways and signaling molecules. Preventing these metabolic derangements may be an alternative way to control excessive inflammation, an intriguing possibility that has not been fully explored. New insight into the molecular pathogenesis of sepsis and sepsis-associated chronic critical illness has led to the recognition of septic cachexia, a life-threatening form of metabolic inflammatory complex associated with multiple organ dysfunction. The potential for septic cachexia to serve as a novel target disease state to improve the clinical outcome of septic patients is discussed in this review.


Subject(s)
Cachexia , Multiple Organ Failure , Sepsis , Animals , Cachexia/immunology , Cachexia/pathology , Cachexia/therapy , Humans , Multiple Organ Failure/immunology , Multiple Organ Failure/pathology , Multiple Organ Failure/therapy , Randomized Controlled Trials as Topic , Sepsis/immunology , Sepsis/pathology , Sepsis/therapy
16.
Shock ; 48(2): 227-235, 2017 08.
Article in English | MEDLINE | ID: mdl-28282360

ABSTRACT

The role of interleukin-6 (IL-6) in physiological processes and disease is poorly understood. The hypothesis tested in this study was that selective alpha7 acetylcholine receptor (α7AChR) agonist, GTS-21, releases IL-6 in association with myonuclear accretion and enhances insulin signaling in muscle cells, and improves survival of burn injured (BI) mice. The in vitro effects of GTS-21 were determined in C2C12 myoblasts and 7-day differentiated myotubes (myotubes). The in vivo effects of GTS-21 were tested in BI wild-type (WT) and IL-6 knockout (IL6KO) mice. GTS-21 dose-dependently (0 µM, 100 µM, and 200 µM) significantly increased IL-6 levels in myoblasts and myotubes at 6 and 9 h. GTS-21-induced IL-6 release in myotubes was attenuated by methyllycaconitine (α7AChR antagonist), and by Stat-3 or Stat-5 inhibitors. GTS-21 increased MyoD and Pax7 protein expression, myonuclear accretion, and insulin-induced phosphorylation of Akt, GSK-3ß, and Glut4 in myotubes. The glucose levels of burned IL6KO mice receiving GTS-21 decreased significantly compared with sham-burn IL6KO mice. Superimposition of BI on IL6KO mice caused 100% mortality; GTS-21 reduced mortality to 75% in the IL6KO mice. The 75% mortality in burned WT mice was reduced to 0% with GTS-21. The in vitro findings suggest that GTS-21-induced IL-6 release from muscle is mediated via α7AChRs upstream of Stat-3 and -5 pathways and is associated with myonuclear accretion, possibly via MyoD and Pax7 expression. GTS-21 in vivo improves survival in burned WT mice and IL6KO mice, suggesting a potential therapeutic application of α7AChR agonists in the treatment of BI.


Subject(s)
Benzylidene Compounds/pharmacology , Burns/drug therapy , Interleukin-6/biosynthesis , Muscle Fibers, Skeletal/metabolism , Muscle Proteins/metabolism , Myoblasts, Skeletal/metabolism , Pyridines/pharmacology , alpha7 Nicotinic Acetylcholine Receptor/agonists , Animals , Burns/genetics , Burns/metabolism , Cell Line , Interleukin-6/genetics , Mice , Mice, Knockout , Muscle Fibers, Skeletal/pathology , Muscle Proteins/genetics , Myoblasts, Skeletal/pathology , alpha7 Nicotinic Acetylcholine Receptor/genetics , alpha7 Nicotinic Acetylcholine Receptor/metabolism
17.
PLoS One ; 12(1): e0170391, 2017.
Article in English | MEDLINE | ID: mdl-28099528

ABSTRACT

Inflammation and apoptosis develop in skeletal muscle after major trauma, including burn injury, and play a pivotal role in insulin resistance and muscle wasting. We and others have shown that inducible nitric oxide synthase (iNOS), a major mediator of inflammation, plays an important role in stress (e.g., burn)-induced insulin resistance. However, it remains to be determined how iNOS induces insulin resistance. Moreover, the interrelation between inflammatory response and apoptosis is poorly understood, although they often develop simultaneously. Nuclear factor (NF)-κB and p53 are key regulators of inflammation and apoptosis, respectively. Sirt1 inhibits p65 NF-κB and p53 by deacetylating these transcription factors. Recently, we have shown that iNOS induces S-nitrosylation of Sirt1, which inactivates Sirt1 and thereby increases acetylation and activity of p65 NF-κB and p53 in various cell types, including skeletal muscle cells. Here, we show that iNOS enhances burn-induced inflammatory response and apoptotic change in mouse skeletal muscle along with S-nitrosylation of Sirt1. Burn injury induced robust expression of iNOS in skeletal muscle and gene disruption of iNOS significantly inhibited burn-induced increases in inflammatory gene expression and apoptotic change. In parallel, burn increased Sirt1 S-nitrosylation and acetylation and DNA-binding capacity of p65 NF-κB and p53, all of which were reversed or ameliorated by iNOS deficiency. These results indicate that iNOS functions not only as a downstream effector but also as an upstream enhancer of burn-induced inflammatory response, at least in part, by Sirt1 S-nitrosylation-dependent activation (acetylation) of p65 NF-κB. Our data suggest that Sirt1 S-nitrosylation may play a role in iNOS-mediated enhanced inflammatory response and apoptotic change, which, in turn, contribute to muscle wasting and supposedly to insulin resistance after burn injury.


Subject(s)
Apoptosis/physiology , Burns/pathology , Inflammation/pathology , Muscle, Skeletal/pathology , Nitric Oxide Synthase Type II/metabolism , Sirtuin 1/metabolism , Transcription Factor RelA/metabolism , Tumor Suppressor Protein p53/metabolism , Acetylation , Animals , DNA-Binding Proteins/metabolism , Enzyme Activation , Mice , Mice, Inbred C57BL , Mice, Knockout , Nitric Oxide Synthase Type II/genetics
18.
Shock ; 47(1): 61-69, 2017 01.
Article in English | MEDLINE | ID: mdl-27529131

ABSTRACT

INTRODUCTION: Muscle wasting (MW) in catabolic conditions (e.g., burn injury [BI]) is a major risk factor affecting prognosis. Activation of interleukin-1ß (IL-1ß)/nuclear factor-kappa B (NF-κB), interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3), and/or forkhead box O transcriptional factor (FOXO)-mediated gene transcription pathways is the pivotal trigger of inflammatory response-induced protein catabolic processes in muscle. The α7 acetylcholine receptors (α7AChRs) are upregulated in macrophages and peripheral tissues including skeletal muscle during MW conditions. Stimulation of α7AChRs mitigates inflammatory responses. Hypothesis tested is that attenuation of inflammation by α7AChR stimulation with specific α7AChR agonist, GTS-21, will reverse BI-induced body mass and MW by modulating inflammatory and proteolytic signals. METHODS: Body surface area (30%) BI or sham BI mice were treated with GTS-21 or saline. Tibialis anterior (TA) muscle was harvested at 6 h, day 1 or 3 to examine inflammatory and proteolytic signals. RESULTS: GTS-21 significantly ameliorated the BI-induced increased expression of inflammatory cytokines IL-6, IL-1ß, C-X-C motif chemokine ligand 2 (6 h), phosphorylated STAT3, and NF-κB (day 1) in TA muscle. GTS-21 also significantly inhibited BI-induced increase of MuRF1 and FOXO1 (day 1). Consistent with the cytokine and inflammatory mediator changes, BI-induced body weight and TA muscle mass loss at day 3 were mitigated by GTS-21 treatment. The beneficial effect of GTS-21 on BI changes was absent in methyllycaconitine (α7AChR antagonist)-treated wild-type and α7AChR knockout mice. CONCLUSION: GTS-21 stimulation of α7AChRs, by modulating multiple molecular signals related to inflammation and proteolysis, attenuates protein wasting, evidenced by maintenance of body weight and attenuation of distant muscle mass loss after BI. GTS-21 can be a novel, potent therapeutic option for reversal of BI-induced MW.


Subject(s)
Benzylidene Compounds/therapeutic use , Burns/drug therapy , Inflammation/metabolism , Inflammation/prevention & control , Muscular Atrophy/metabolism , Muscular Atrophy/prevention & control , Pyridines/therapeutic use , alpha7 Nicotinic Acetylcholine Receptor/antagonists & inhibitors , Animals , Burns/complications , Burns/metabolism , Immunoblotting , Inflammation/etiology , Male , Mice , Mice, Inbred C57BL , Muscular Atrophy/etiology
19.
J Cell Physiol ; 232(1): 192-201, 2017 01.
Article in English | MEDLINE | ID: mdl-27137755

ABSTRACT

The aggressiveness of triple-negative breast cancer (TNBC), which lacks estrogen receptor, progesterone receptor and epidermal growth factor receptor 2 (HER2), represents a major challenge in breast cancer. Migratory and self-renewal capabilities are integral components of invasion, metastasis and recurrence of TNBC. Elevated hypoxia-inducible factor-1α (HIF-1α) expression is associated with aggressiveness of cancer. Nonetheless, how HIF-1α expression is regulated and how HIF-1α induces aggressive phenotype are not completely understood in TNBC. The cytotoxic effects of farnesyltransferase (FTase) inhibitors (FTIs) have been studied in cancer and leukemia cells. In contrast, the effect of FTIs on HIF-1α expression has not yet been studied. Here, we show that clinically relevant low-dose FTI, tipifarnib (300 nM), decreased HIF-1α expression, migration and tumorsphere formation in human MDA-MB-231 TNBC cells under a normoxic condition. In contrast, the low-dose FTIs did not inhibit cell growth and activity of the Ras pathway in MDA-MB 231 cells. Tipifarnib-induced decrease in HIF-1α expression was associated with amelioration of the Warburg effect, hypermetabolic state, increases in Snail expression and ATP release, and suppressed E-cadherin expression, major contributors to invasion, metastasis and recurrence of TBNC. These data suggest that FTIs may be capable of ameliorating the aggressive phenotype of TNBC by suppressing the HIF-1α-Snail pathway. J. Cell. Physiol. 232: 192-201, 2017. © 2016 Wiley Periodicals, Inc.


Subject(s)
ErbB Receptors/metabolism , Farnesyltranstransferase/antagonists & inhibitors , Gene Expression Regulation, Neoplastic/drug effects , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Receptors, Estrogen/metabolism , Triple Negative Breast Neoplasms/metabolism , Cadherins/metabolism , Cell Line, Tumor , Cell Proliferation/physiology , Female , Humans , Quinolones/pharmacology , Signal Transduction/drug effects , Triple Negative Breast Neoplasms/genetics
20.
Sci Rep ; 6: 29874, 2016 07 20.
Article in English | MEDLINE | ID: mdl-27435513

ABSTRACT

Postoperative delirium is associated with increased morbidity, mortality and cost. However, its neuropathogenesis remains largely unknown, partially owing to lack of animal model(s). We therefore set out to employ a battery of behavior tests, including natural and learned behavior, in mice to determine the effects of laparotomy under isoflurane anesthesia (Anesthesia/Surgery) on these behaviors. The mice were tested at 24 hours before and at 6, 9 and 24 hours after the Anesthesia/Surgery. Composite Z scores were calculated. Cyclosporine A, an inhibitor of mitochondria permeability transient pore, was used to determine potential mitochondria-associated mechanisms of these behavioral changes. Anesthesia/Surgery selectively impaired behaviors, including latency to eat food in buried food test, freezing time and time spent in the center in open field test, and entries and duration in the novel arm of Y maze test, with acute onset and various timecourse. The composite Z scores quantitatively demonstrated the Anesthesia/Surgery-induced behavior impairment in mice. Cyclosporine A selectively ameliorated the Anesthesia/Surgery-induced reduction in ATP levels, the increases in latency to eat food, and the decreases in entries in the novel arm. These findings suggest that we could use a battery of behavior tests to establish a mouse model to study postoperative delirium.


Subject(s)
Anesthetics, Inhalation/adverse effects , Delirium/physiopathology , Maze Learning/physiology , Postoperative Complications/physiopathology , Animals , Behavior Rating Scale , Behavior, Animal/drug effects , Delirium/chemically induced , Humans , Maze Learning/drug effects , Memory/drug effects , Mice , Postoperative Complications/chemically induced
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