Tabersonine Enhances Olaparib Sensitivity through FHL1-Mediated Epithelial-Mesenchymal Transition in an Ovarian Tumor.

Ovarian cancer (OVC) is one of the most aggressive gynecological malignancies worldwide. Although olaparib treatment has shown favorable outcomes against the treatment of OVC, its effectiveness remains limited in some OVC patients. Investigating new strategies to improve the therapeutic efficacy of olaparib against OVC is imperative. Our study identified tabersonine, a natural indole alkaloid, for its potential to increase the chemosensitivity of olaparib in OVC. The combined treatment of olaparib and tabersonine synergistically inhibited cell proliferation in OVC cells and suppressed tumor growth in A2780 xenografts. The combined treatment effectively suppressed epithelial-mesenchymal transition (EMT) by altering the expression of E-cadherin, N-cadherin, and vimentin and induced DNA damage responses. Integrating quantitative proteomics, FHL1 was identified as a potential regulator to modulate EMT after tabersonine treatment. Increased expression of FHL1 was induced by tabersonine treatment, while downregulation of FHL1 reversed the inhibitory effects of tabersonine on OVC cells by mediating EMT. In vivo findings further reflected that the combined treatment of tabersonine and olaparib significantly inhibited tumor growth and OVC metastasis through upregulation of FHL1. Our findings reveal the role of tabersonine in improving the sensitivity of olaparib in OVC through FHL1-mediated EMT, suggesting that tabersonine holds promise for future application in OVC treatment.

Storax Attenuates Cardiac Fibrosis following Acute Myocardial Infarction in Rats via Suppression of AT1R-Ankrd1-P53 Signaling Pathway.

Myocardial fibrosis following acute myocardial infarction (AMI) seriously affects the prognosis and survival rate of patients. This study explores the role and regulation mechanism of storax, a commonly used traditional Chinese medicine for treatment of cardiovascular diseases, on myocardial fibrosis and cardiac function. The AMI rat model was established by subcutaneous injection of Isoproterenol hydrochloride (ISO). Storax (0.1, 0.2, 0.4 g/kg) was administered by gavage once/d for 7 days. Electrocardiogram, echocardiography, hemodynamic and cardiac enzyme in AMI rats were measured. HE, Masson, immunofluorescence and TUNEL staining were used to observe the degree of pathological damage, fibrosis and cardiomyocyte apoptosis in myocardial tissue, respectively. Expression of AT1R, CARP and their downstream related apoptotic proteins were detected by WB. The results demonstrated that storax could significantly improve cardiac electrophysiology and function, decrease serum cardiac enzyme activity, reduce type I and III collagen contents to improve fibrosis and alleviate myocardial pathological damage and cardiomyocyte apoptosis. It also found that storax can significantly down-regulate expression of AT1R, Ankrd1, P53, P-p53 (ser 15), Bax and cleaved Caspase-3 and up-regulate expression of Mdm2 and Bcl-2. Taken together, these findings indicated that storax effectively protected cardiomyocytes against myocardial fibrosis and cardiac dysfunction by inhibiting the AT1R-Ankrd1-P53 signaling pathway.

The effect of a chemotherapy drug cocktail on myotube morphology, myofibrillar protein abundance, and substrate availability.

Cachexia, a condition prevalent in many chronically ill patients, is characterized by weight loss, fatigue, and decreases in muscle mass and function. Cachexia is associated with tumor burden and disease-related malnutrition, but other studies implicate chemotherapy as being causative. We investigated the effects of a chemotherapy drug cocktail on myofibrillar protein abundance and synthesis, anabolic signaling mechanisms, and substrate availability. On day 4 of differentiation, L6 myotubes were treated with vehicle (1.4 µl/ml DMSO) or a chemotherapy drug cocktail (a mixture of cisplatin [20 µg/ml], leucovorin [10 µg/ml], and 5-fluorouracil [5-FLU; 50 µg/ml]) for 24-72 h. Compared to myotubes treated with vehicle, those treated with the drug cocktail showed 50%-80% reductions in the abundance of myofibrillar proteins, including myosin heavy chain-1, troponin, and tropomyosin (p < 0.05). Cells treated with only a mixture of cisplatin and 5-FLU had identical reductions in myofibrillar protein abundance. Myotubes treated with the drug cocktail also showed >50% reductions in the phosphorylation of AKTSer473 and of mTORC1 substrates ribosomal protein S6Ser235/236 , its kinase S6K1Thr389 and eukaryotic translation initiation factor 4E-binding protein 1 (all p < 0.05). Drug treatment impaired peptide chain initiation in myofibrillar protein fractions and insulin-stimulated glucose uptake (p = 0.06) but increased the expression of autophagy markers beclin-1 and microtubule-associated proteins 1A/1B light chain 3B (p < 0.05), and of apoptotic marker, cleaved caspase 3 (p < 0.05). Drug treatment reduced the expression of mitochondrial markers cytochrome oxidase and succinate dehydrogenase (p < 0.05). The observed profound negative effects of this chemotherapy drug cocktail on myotubes underlie a need for approaches that can reduce the negative effects of these drugs on muscle metabolism.

Reducing NF-κB Signaling Nutritionally is Associated with Expedited Recovery of Skeletal Muscle Function After Damage.

CONTEXT: The early events regulating the remodeling program following skeletal muscle damage are poorly understood. OBJECTIVE: The objective of this study was to determine the association between myofibrillar protein synthesis (myoPS) and nuclear factor-kappa B (NF-κB) signaling by nutritionally accelerating the recovery of muscle function following damage. DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS: Healthy males and females consumed daily postexercise and prebed protein-polyphenol (PP; n = 9; 4 females) or isocaloric maltodextrin placebo (PLA; n = 9; 3 females) drinks (parallel design) 6 days before and 3 days after 300 unilateral eccentric contractions of the quadriceps during complete dietary control. MAIN OUTCOME MEASURES: Muscle function was assessed daily, and skeletal muscle biopsies were taken after 24, 27, and 36 hours for measurements of myoPS rates using deuterated water, and gene ontology and NF-κB signaling analysis using a quantitative reverse transcription PCR (RT-qPCR) gene array. RESULTS: Eccentric contractions impaired muscle function for 48 hours in PLA intervention, but just for 24 hours in PP intervention (P = 0.047). Eccentric quadricep contractions increased myoPS compared with the control leg during postexercise (24-27 hours; 0.14 ± 0.01 vs 0.11 ± 0.01%·h-1, respectively; P = 0.075) and overnight periods (27-36 hours; 0.10 ± 0.01 vs 0.07 ± 0.01%·h-1, respectively; P = 0.020), but was not further increased by PP drinks (P > 0.05). Protein-polyphenol drinks decreased postexercise and overnight muscle IL1R1 (PLA = 2.8 ± 0.4, PP = 1.1 ± 0.4 and PLA = 1.9 ± 0.4, PP = 0.3 ± 0.4 log2 fold-change, respectively) and IL1RL1 (PLA = 4.9 ± 0.7, PP = 1.6 ± 0.8 and PLA = 3.7 ± 0.6, PP = 0.7 ± 0.7 log2 fold-change, respectively) messenger RNA expression (P < 0.05) and downstream NF-κB signaling compared with PLA. CONCLUSION: Protein-polyphenol drink ingestion likely accelerates recovery of muscle function by attenuating inflammatory NF-κB transcriptional signaling, possibly to reduce aberrant tissue degradation rather than increase myoPS rates.

Ursolic acid ameliorates hypobaric hypoxia-induced skeletal muscle protein loss via upregulating Akt pathway: An experimental study using rat model.

Hypobaric hypoxic stress leads to oxidative stress, inflammation, and disturbance in protein turnover rate. Aggregately, this imbalance in redox homeostasis is responsible for skeletal muscle protein loss and a decline in physical performance. Hence, an urgent medical need is required to ameliorate skeletal muscle protein loss. The present study investigated the efficacy of ursolic acid (UA), a pentacyclic triterpene acid to ameliorate hypobaric hypoxia (HH)-induced muscle protein loss. UA is a naturally occurring pentacyclic triterpene acid present in several edible herbs and fruits such as apples. It contains skeletal muscle hypertrophy activity; still its potential against HH-induced muscle protein loss is unexplored. To address this issue, an in vivo study was planned to examine the beneficial effect of UA supplementation on HH-induced skeletal muscle loss. Male Sprague Dawley rats were exposed to HH with and without UA supplementation (20 mg/kg; oral) for 3 continuous days. The results described the beneficial role of UA as supplementation of UA with HH exposure attenuated reactive oxygen species production and oxidative protein damage, which indicate the potent antioxidant activity. Furthermore, UA supplementation enhanced Akt, pAkt, and p70S6kinase activity (Akt pathway) and lowered the pro-inflammatory cytokines in HH exposed rats. UA has potent antioxidant and anti-inflammatory activity, and it enhanced the protein content via upregulation of Akt pathway-related proteins against HH exposure. These three biological activities of UA make it a novel candidate for amelioration of HH-induced skeletal muscle damage and protein loss.

Potential effects of long-term abuse of anabolic androgen steroids on human skeletal muscle.

BACKGROUND: We have previously evaluated muscle functions and morphology in power athletes of long term (5 to15 years) abuse of anabolic androgen steroids (AAS; Doped) and in clean power athletes (Clean), and observed significant improvements in both muscle morphology and muscle functions in Doped. To our knowledge, the effects of long term AAS abuse on human muscle protein profile have never been studied. METHODS: The study examined further the muscle biopsies using a two-dimensional difference gel electrophoresis (2D DIGE) for proteomic screening and protein expression. Cellular localization/distribution of specific proteins identified by proteomic analysis was examined using immunohistochemistry (IHC). RESULTS: Different protein profiles were observed between Doped and Clean, and a valid orthogonal projection of latent structure discriminant analysis model was built (N.=16, x=5, R2=0.88/Q2=0.84, P=0.0005), which separated Doped from Clean. Liquid chromatography followed by tandem spectrometry identified 14 protein spots (representing nine different proteins) of significant difference in relative quantity (P<0.05), of which nine spots were down-regulated in Doped compared with Clean. IHC revealed no significant alteration in cellular localization in phosphoglucomutase-1 and heat shock protein beta-1, but indeed in two reference proteins desmin and F-actin in Doped. CONCLUSIONS: Long term abuse of AAS in combination with training is potentially associated with alterations in skeletal muscle protein profile and protein expression, and structural proteins rather than non-structural proteins are preferentially affected in cellular localization/distribution.

Icotinib Attenuates Monocrotaline-Induced Pulmonary Hypertension by Preventing Pulmonary Arterial Smooth Muscle Cell Dysfunction.

BACKGROUND: Aberrant activation of epidermal growth factor receptor (EGFR) signaling pathway is associated with the pathogenesis of pulmonary hypertension (PH). However, the effect of icotinib, a first generation of EGFR tyrosine kinase inhibitor (EGFR-TKI), on PH remains to be elucidated. METHODS: PH rat model was established by a single intraperitoneal injection of monocrotaline (MCT, 60 mg/kg). Icotinib (15, 30, and 60 mg/kg/day) was administered by oral gavage from the day of MCT injection. After 4 weeks, hemodynamic parameters and histological changes of the pulmonary arterial vessels were assessed, and the phenotypic switching of pulmonary arterial smooth muscle cells (PASMCs) was determined in vivo. Moreover, the effects of icotinib (10 µM) on epidermal growth factor (EGF, 50 ng/ml)-stimulated proliferation, migration, and phenotypic switching of human PASMCs were explored in vitro. RESULTS: Icotinib significantly reduced the right ventricular systolic pressure and right ventricle hypertrophy index in rats with MCT-induced PH. Moreover, icotinib improved MCT-induced pulmonary vascular remodeling. The expression of contractile marker (smooth muscle 22 alpha (SM22α)) and synthetic markers (osteopontin (OPN) and vimentin) in pulmonary artery was restored by icotinib treatment. In vitro, icotinib suppressed EGF-induced PASMCs proliferation and migration. Meanwhile, icotinib inhibited EGF-induced downregulation of α-smooth muscle actin and SM22α and upregulation of OPN and Collagen I in PASMCs, suggesting that icotinib could inhibit EGF-induced phenotypic switching of PASMCs. Mechanistically, these effects of icotinib were associated with the inhibition of EGFR-Akt/ERK signaling pathway. CONCLUSIONS: Icotinib can attenuate MCT-induced pulmonary vascular remodeling and improve PH. This effect of icotinib might be attributed to preventing PASMC dysfunction by inhibiting EGFR-Akt/ERK signaling pathway.

4-Aminopyridine attenuates muscle atrophy after sciatic nerve crush injury in mice.

INTRODUCTION: We recently demonstrated the beneficial effects of 4-aminopyridine (4-AP), a potassium channel blocker, in enhancing remyelination and recovery of nerve conduction velocity and motor function after sciatic nerve crush injury in mice. Although muscle atrophy occurs very rapidly after nerve injury, the effect of 4-AP on muscle atrophy and intrinsic muscle contractile function is largely unknown. METHODS: Mice were assigned to sciatic nerve crush injury and no-injury groups and were followed for 3, 7, and 14 days with/without 4-AP or saline treatment. Morphological, functional, and transcriptional properties of skeletal muscle were assessed. RESULTS: In addition to improving in vivo function, 4-AP significantly reduced muscle atrophy with increased muscle fiber diameter and contractile force. Reduced muscle atrophy was associated with attenuated expression of atrophy-related genes and increased expression of proliferating stem cells. DISCUSSION: These findings provide new insights into the potential therapeutic benefits of 4-AP against nerve injury-induced muscle atrophy and dysfunction. Muscle Nerve 60: 192-201, 2019.

Arsenic Trioxide Inhibits the Metastasis of Small Cell Lung Cancer by Blocking Calcineurin-Nuclear Factor of Activated T Cells (NFAT) Signaling.

BACKGROUND The inhibitory effect of arsenic trioxide (As2O3) on lung cancer has been reported in some preclinical studies. However, its effect on small cell lung cancer (SCLC) has been poorly explored. Calcineurin and its substrate, nuclear factor of activated T cells (NFAT), mediate the downstream signaling of VEGF, and is critical in the process endothelium activation and tumor metastasis. In this study, we aimed to evaluate whether As2O3 had inhibitory effects on endothelial cells activation and the metastasis of SCLC, and to explore the possible mechanisms. MATERIAL AND METHODS In vitro, human umbilical vein endothelial cells (HUVECs) were used. Cell Counting Kit-8 assay and cell migration assay were performed to determine the effect of As2O3 on HUVECs proliferation and migration. The level of calcineurin, NFAT, downstream factors for Down syndrome candidate region 1 (DSCR1), and the endogenous inhibitor of calcineurin, were evaluated by quantitative PCR and western blotting. In vivo, SCLC metastasis models were established by injecting NCI-H446 cells into tail veins of nude mice. Tumor-bearing mice were treated with As2O3 or calcineurin inhibitor for 10 days, after which tumor metastasis in target organs was evaluated. RESULTS As2O3 significantly inhibited the proliferation and migration of endothelial cells. Also, As2O3 inhibited the expression levels of calcineurin, NFAT, and the downstream target genes CXCR7 and RND1, while it upregulated the level of DSCR1. Both As2O3 and calcineurin inhibitor exhibited notable inhibitory effect on the metastasis of SCLC, without obvious side effects. CONCLUSIONS These findings suggested that As2O3 had remarkable inhibitory effects on the endothelial cell activation and SCLC metastasis, and the mechanism might be related to the blocking of calcineurin-NFAT signaling by upregulating DSCR1.

The effect of acute oral phosphatidic acid ingestion on myofibrillar protein synthesis and intracellular signaling in older males.

BACKGROUND: Age-related muscle loss (sarcopenia) may be driven by a diminished myofibrillar protein synthesis (MyoPS) response to anabolic stimuli (i.e. exercise and nutrition). Oral phosphatidic acid (PA) ingestion has been reported to stimulate resting muscle protein synthesis in rodents, and enhance resistance training-induced muscle remodelling in young humans. PURPOSE: This study examined the effects of acute oral PA ingestion on resting and exercise-induced MyoPS rates in older individuals. METHODS: Sixteen older males performed a bout of unilateral leg resistance exercise followed by oral ingestion of 750 mg of soy-derived PA or a rice-flour placebo (PL) over 60 min post-exercise. A primed-continuous infusion of l-[ring-13C6]-phenylalanine with serial muscle biopsies was used to determine MyoPS at rest and between 0-150 and 150-300 min post-exercise. RESULTS: Plasma [PA] concentrations were elevated above basal values from 180 to 300 min post-exercise in PA only (P = 0.02). Exercise increased MyoPS rates above basal values between 150 and 300 min post-exercise in PL (P = 0.001), but not PA (P = 0.83). Phosphorylation of p70S6K, rpS6, 4E-BP1 and Akt was elevated above basal levels in the exercised leg over 150-300 min post-exercise for PL only (P = 0.018, 0.007, 0.011 and 0.002, respectively), and were significantly greater than PA (P < 0.01 for all proteins). The effects of oral PA ingestion on proteolytic signaling markers were equivocal. CONCLUSIONS: Acute oral phosphatidic acid ingestion appears to interfere with resistance exercise-induced intramuscular anabolic signaling and MyoPS in older males and, therefore, may not be a viable treatment to counteract sarcopenia. Clinicaltials.gov registration no: NCT03446924.

Oxaliplatin induces muscle loss and muscle-specific molecular changes in Mice.

INTRODUCTION: Muscle wasting is a frequent, debilitating complication of cancer. The impact of colorectal cancer chemotherapeutic oxaliplatin on the development of muscle loss and associated molecular changes is of clinical importance. METHODS: C57BL/6J male mice were treated with oxaliplatin. Total body weights were measured and behavioral studies performed. Hindlimb muscle weights (gastrocnemius and soleus) were recorded in conjunction with gene and protein expression analysis. RESULTS: Oxaliplatin-treated mice displayed reduced weight gain and behavioral deficits. Mice treated over a shorter course had significantly increased STAT3 phosphorylation in gastrocnemius muscles. Mice receiving extended oxaliplatin treatment demonstrated reduced hindlimb muscle mass with upregulation of myopathy-associated genes Foxo3, MAFbx, and Bnip3. DISCUSSION: The findings suggest that oxaliplatin treatment can directly disrupt skeletal muscle homeostasis and promote muscle loss, which may be clinically relevant in the context of targeting fatigue and weakness in cancer patients. Muscle Nerve 57: 650-658, 2018.

Myofibrillogenesis regulator 1 (MR-1): a potential therapeutic target for cancer and PNKD.

Human myofibrillogenesis regulator 1 (MR-1) is a functional gene also known as paroxysmal nonkinesigenic dyskinesia (PNKD). It is localised on human chromosome 2q35 and three different isomers, MR-1L, MR-1M and MR-1S, are formed by alternative splicing. MR-1S promotes cardiac hypertrophy and is closely related to cancer. MR-1S is overexpressed in haematologic and solid malignancies, such as hepatoma, breast cancer and chronic myelogenous leukaemia. MR-1S causes disordered cell differentiation, initiates malignant transformation and accelerates metastasis. MR-1S directly phosphorylates and activates the MEK-ERK-RSK pathway to accelerate cancer growth and facilitates metastasis by activating the MLC2-FAK-AKT pathway. Silencing MR-1 inhibits cancer cell proliferation and metastasis. MR-1S causes disordered cell differentiation, initiates malignant transformation and accelerates metastasis. MR-1 interacts with eukaryotic translation initiation factors and MRIP-1, which contains Ras GTPase, PH and zinc-containing ArfGap domains, as well as three ankyrin repeats. Mutations in the N-terminal region of MR-1L and MR-1S are the main causes of PNKD (a hereditary disease characterised by paroxysmal dystonic choreoathetosis) and targeting the mutated protein could provide symptomatic relief. These findings provide compelling evidence that MR-1 might be a diagnostic marker and therapeutic target for solid tumours, myelogenous leukaemia and PNKD.

Attenuation of Resting but Not Load-Mediated Protein Synthesis in Prostate Cancer Patients on Androgen Deprivation.

CONTEXT: Androgen deprivation therapy (ADT) is a common prostate cancer (PCa) treatment but results in muscular atrophy. Periodic increases in muscle protein synthesis (MPS) that occur after resistance exercise or protein intake may ameliorate this muscle loss, but the impact of these anabolic stimuli during ADT is unclear. OBJECTIVE: To determine the acute MPS response to whey protein supplementation with and without resistance exercise during ADT. DESIGN: Acute response in PCa patients vs age-matched controls (CON). SETTING: Academic laboratory setting. PARTICIPANTS: PCa patients on ADT (N = 8) and CON (N = 10). INTERVENTION: A standardized diet was consumed for 2 days prior to performing unilateral knee extension resistance exercise followed by ingestion of 40 g of whey protein. MAIN OUTCOME MEASURES: Bilateral biopsies and stable isotope infusions were used to determine MPS rates at rest after protein ingestion with and without resistance exercise. RESULTS: Baseline MPS during ADT was suppressed relative to CON (P = 0.01). Protein consumption stimulated MPS in both groups (approximate twofold increase, both P < 0.001), but to a greater extent in CON (P = 0.003). Protein plus resistance exercise increased MPS (∼3.4-fold increase, both P < 0.001) to a greater extent than did protein alone (P < 0.001), but with no difference between groups (P = 0.380). CONCLUSIONS: ADT reduces basal and protein feeding-induced rises in MPS; however, combined protein ingestion with resistance exercise stimulated MPS to a similar degree as CON. Testosterone appears to play a role in maintaining muscle mass but is not necessary to initiate a robust response in MPS following resistance exercise when combined with protein ingestion.

Citrulline directly modulates muscle protein synthesis via the PI3K/MAPK/4E-BP1 pathway in a malnourished state: evidence from in vivo, ex vivo, and in vitro studies.

Citrulline (CIT) is an endogenous amino acid produced by the intestine. Recent literature has consistently shown CIT to be an activator of muscle protein synthesis (MPS). However, the underlying mechanism is still unknown. Our working hypothesis was that CIT might regulate muscle homeostasis directly through the mTORC1/PI3K/MAPK pathways. Because CIT undergoes both interorgan and intraorgan trafficking and metabolism, we combined three approaches: in vivo, ex vivo, and in vitro. Using a model of malnourished aged rats, CIT supplementation activated the phosphorylation of S6K1 and 4E-BP1 in muscle. Interestingly, the increase in S6K1 phosphorylation was positively correlated (P < 0.05) with plasma CIT concentration. In a model of isolated incubated skeletal muscle from malnourished rats, CIT enhanced MPS (from 30 to 80% CIT vs. Ctrl, P < 0.05), and the CIT effect was abolished in the presence of wortmannin, rapamycin, and PD-98059. In vitro, on myotubes in culture, CIT led to a 2.5-fold increase in S6K1 phosphorylation and a 1.5-fold increase in 4E-BP1 phosphorylation. Both rapamycin and PD-98059 inhibited the CIT effect on S6K1, whereas only LY-294002 inhibited the CIT effect on both S6K1 and 4E-BP1. These findings show that CIT is a signaling agent for muscle homeostasis, suggesting a new role of the intestine in muscle mass control.

Myostatin promotes distinct responses on protein metabolism of skeletal and cardiac muscle fibers of rodents

Myostatin is a novel negative regulator of skeletal muscle mass. Myostatin expression is also found in heart in a much less extent, but it can be upregulated in pathological conditions, such as heart failure. Myostatin may be involved in inhibiting protein synthesis and/or increasing protein degradation in skeletal and cardiac muscles. Herein, we used cell cultures and isolated muscles from rats to determine protein degradation and synthesis. Muscles incubated with myostatin exhibited an increase in proteolysis with an increase of Atrogin-1, MuRF1 and LC3 genes. Extensor digitorum longus muscles and C2C12 myotubes exhibited a reduction in protein turnover. Cardiomyocytes showed an increase in proteolysis by activating autophagy and the ubiquitin proteasome system, and a decrease in protein synthesis by decreasing P70S6K. The effect of myostatin on protein metabolism is related to fiber type composition, which may be associated to the extent of atrophy mediated effect of myostatin on muscle.

No effect of anti-inflammatory medication on postprandial and postexercise muscle protein synthesis in elderly men with slightly elevated systemic inflammation.

BACKGROUND: Based on circulating C-reactive protein (CRP) levels, some individuals develop slightly increased inflammation as they age. In elderly inflamed rats, the muscle response to protein feeding is impaired, whereas it can be maintained by treatment with non-steroidal anti-inflammatory drugs (NSAIDs). It is unknown whether this applies to elderly humans with increased inflammation. Thus, the muscle response to whey protein bolus ingestion with and without acute resistance exercise was compared between healthy elderly individuals and elderly individuals with slightly increased inflammation±NSAID treatment. METHODS: Twenty-four elderly men (>60years) were recruited. Of those, 14 displayed a slightly increased systemic inflammation (CRP>2mg/l) and were randomly assigned to NSAID (Ibuprofen 1800mg/day) or placebo treatment for 1week. The remaining 10 elderly individuals served as healthy controls (CRP<1mg/l). The muscle protein synthetic response was measured as the fractional synthetic rate (FSR) and p70S6K phosphorylation-to-total protein ratio. RESULTS: The basal myofibrillar FSR and the myofibrillar FSR responses to whey protein bolus ingestion with and without acute resistance exercise were maintained in inflamed elderly compared to healthy controls (p>0.05) and so was p70S6K phosphorylation. Moreover, NSAID treatment did not significantly improve the myofibrillar and connective tissue FSR responses or reduce the plasma CRP level in inflamed, elderly individuals (p>0.05). CONCLUSION: A slight increase in systemic inflammation does not affect the basal myofibrillar FSR or the myofibrillar FSR responses, which suggests that elderly individuals with slightly increased inflammation can benefit from protein ingestion and resistance exercise to stimulate muscle protein anabolism. Moreover, the NSAID treatment did not significantly affect the myofibrillar or connective tissue FSR responses to protein ingestion and acute resistance exercise.

Adverse effects of androgen deprivation therapy and strategies to mitigate them.

CONTEXT: Androgen-deprivation therapy (ADT) is a key component of treatment for aggressive and advanced prostate cancer, but it has also been associated with adverse effects on bone, metabolic, cardiovascular, sexual, and cognitive health as well as body composition. OBJECTIVE: To review the current literature on the adverse effects of ADT and strategies for ameliorating harm from ADT. EVIDENCE ACQUISITION: The Medline database (through PubMed) was searched from inception to August 1, 2013, for studies documenting the side effects of ADT and for randomized and prospective trials of interventions to mitigate those side effects. EVIDENCE SYNTHESIS: Adverse effects of ADT include decreases in bone mineral density; metabolic changes such as weight gain, decreased muscle mass, and increased insulin resistance; decreased libido and sexual dysfunction; hot flashes; gynecomastia; reduced testicle size; anemia; and fatigue. Several observational studies suggest an increased risk of diabetes and cardiovascular events, although most published studies report that ADT is not linked to greater cardiovascular mortality. Randomized trials have found value in treatments for some adverse effects including bone loss (bisphosphonates, denosumab, selective estrogen receptor modulators), markers of metabolic syndrome (exercise, diet, metformin), gynecomastia (tamoxifen, prophylactic radiation), muscle loss (resistance and aerobic exercise), and hot flashes (venlafaxine, medroxyprogesterone, cyproterone acetate, gabapentin). CONCLUSIONS: ADT is often a necessary component of the treatment of aggressive prostate cancer, yet it has known harms that can impair health and quality of life. Clinicians should be aware of interventions that can help mitigate these adverse effects. PATIENT SUMMARY: Androgen deprivation therapy is a critical component of the management of aggressive and advanced prostate cancer, but it causes adverse effects including bone loss, metabolic changes, gynecomastia, muscle loss, hot flashes, and possibly increased cardiovascular events. Clinicians should be aware of interventions that can help mitigate these adverse effects.

Identification of the STAC3 gene as a skeletal muscle-specifically expressed gene and a novel regulator of satellite cell differentiation in cattle.

Recent studies in mice and zebrafish suggest that the unannotated Src homology 3 and cysteine rich domain 3 (STAC3) gene plays an important role in skeletal muscle development and contraction. The objective of this study was to determine the tissue specificity of the bovine STAC3 gene and its potential role in the proliferation and differentiation of bovine satellite cells. The STAC3 mRNA was detected only in skeletal muscle among 18 bovine tissues examined by reverse transcription PCR. Western blotting revealed the expression of STAC3 protein in bovine skeletal muscle and the absence of it in 6 bovine tissues analyzed. Transfection of the bovine satellite cells with a pool of 2 STAC3 small interfering RNA (siRNA) caused a 90% reduction in STAC3 mRNA. Cell proliferation assays revealed that STAC3 knockdown had no effect on the proliferation rate of bovine satellite cells. Approximately 60% of bovine satellite cells transfected with STAC3 siRNA formed myotubes by 72 h of differentiation, whereas that percentage was 40% for those transfected with negative control siRNA (P < 0.05). At 24, 48, and 72 h of differentiation, bovine satellite cells transfected with STAC3 siRNA had greater mRNA expression of myogenin, myosin heavy chain 3, and myosin heavy chain 7, markers of myotubes, than those transfected with negative control siRNA (P < 0.05). These results suggest that the STAC3 gene is a negative regulator of the differentiation and fusion of bovine satellite cells into myotubes. However, STAC3 expression was increased during the differentiation of bovine satellite cells into myotubes. This suggests that STAC3 might have different functions in bovine myotubes than in bovine satellite cells.

Expression of androgen receptor target genes in skeletal muscle.

We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor (AR)-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity (AR(ΔZF2)) versus wildtype mice, demonstrating that myogenin is repressed by the androgen/AR pathway. The ubiquitin ligase Fbxo32 was repressed by 12 h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, and c-Myc expression was decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR(∆ZF2) muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7 , p57(Kip2), Igf2 and calcineurin Aa, was increased in AR(∆ZF2) muscle, and the expression of all but p57(Kip2) was also decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase-mediated atrophy pathways to preserve muscle mass in adult muscle.

Influence of divergent exercise contraction mode and whey protein supplementation on atrogin-1, MuRF1, and FOXO1/3A in human skeletal muscle.

Knowledge from human exercise studies on regulators of muscle atrophy is lacking, but it is important to understand the underlying mechanisms influencing skeletal muscle protein turnover and net protein gain. This study examined the regulation of muscle atrophy-related factors, including atrogin-1 and MuRF1, their upstream transcription factors FOXO1 and FOXO3A and the atrogin-1 substrate eIF3-f, in response to unilateral isolated eccentric (ECC) vs. concentric (CONC) exercise and training. Exercise was performed with whey protein hydrolysate (WPH) or isocaloric carbohydrate (CHO) supplementation. Twenty-four subjects were divided into WPH and CHO groups and completed both single-bout exercise and 12 wk of training. Single-bout ECC exercise decreased atrogin-1 and FOXO3A mRNA compared with basal and CONC exercise, while MuRF1 mRNA was upregulated compared with basal. ECC exercise downregulated FOXO1 and phospho-FOXO1 protein compared with basal, and phospho-FOXO3A was downregulated compared with CONC. CONC single-bout exercise mediated a greater increase in MuRF1 mRNA and increased FOXO1 mRNA compared with basal and ECC. CONC exercise downregulated FOXO1, FOXO3A, and eIF3-f protein compared with basal. Following training, an increase in basal phospho-FOXO1 was observed. While WPH supplementation with ECC and CONC training further increased muscle hypertrophy, it did not have an additional effect on mRNA or protein levels of the targets measured. In conclusion, atrogin-1, MuRF1, FOXO1/3A, and eIF3-f mRNA, and protein levels, are differentially regulated by exercise contraction mode but not WPH supplementation combined with hypertrophy-inducing training. This highlights the complexity in understanding the differing roles these factors play in healthy muscle adaptation to exercise.