ABSTRACT
Limited knowledge exists regarding the chronic effect of muscular exercise on muscle function in a murine model of severe Duchenne muscular dystrophy (DMD). Here we determined the effects of 1 month of voluntary wheel running (WR), 1 month of enforced treadmill running (TR) and 1 month of mechanical overloading resulting from the removal of the synergic muscles (OVL) in mice lacking both dystrophin and desmin (DKO). Additionally, we examined the effect of activin receptor administration (AR). DKO mice, displaying severe muscle weakness, atrophy and greater susceptibility to contraction-induced functional loss, were exercised or treated with AR at 1 month of age and in situ force production of lower leg muscle was measured at the age of 2 months. We found that TR and OVL increased absolute maximal force and the rate of force development of the plantaris muscle in DKO mice. In contrast, those of the tibialis anterior (TA) muscle remained unaffected by TR and WR. Furthermore, the effects of TR and OVL on plantaris muscle function in DKO mice closely resembled those in mdx mice, a less severe murine DMD model. AR also improved absolute maximal force and the rate of force development of the TA muscle in DKO mice. In conclusion, exercise training improved plantaris muscle weakness in severely affected dystrophic mice. Consequently, these preclinical results may contribute to fostering further investigations aimed at assessing the potential benefits of exercise for DMD patients, particularly resistance training involving a low number of intense muscle contractions. KEY POINTS: Very little is known about the effects of exercise training in a murine model of severe Duchenne muscular dystrophy (DMD). One reason is that it is feared that chronic muscular exercise, particularly that involving intense muscle contractions, could exacerbate the disease. In DKO mice lacking both dystrophin and desmin, characterized by severe lower leg muscle weakness, atrophy and fragility in comparison to the less severe DMD mdx model, we found that enforced treadmill running improved absolute maximal force of the plantaris muscle, while that of tibialis anterior muscle remained unaffected by both enforced treadmill and voluntary wheel running. Furthermore, mechanical overloading, a non-physiological model of chronic resistance exercise, reversed plantaris muscle weakness. Consequently, our findings may have the potential to alleviate concerns and pave the way for exploring the prescription of endurance and resistance training as a viable therapeutic approach for the treatment of dystrophic patients. Additionally, such interventions may serve in mitigating the pathophysiological mechanisms induced by physical inactivity.
Subject(s)
Desmin , Dystrophin , Muscle, Skeletal , Physical Conditioning, Animal , Running , Animals , Male , Mice , Desmin/genetics , Desmin/metabolism , Dystrophin/genetics , Mice, Inbred C57BL , Mice, Inbred mdx , Mice, Knockout , Muscle Contraction , Muscle Strength , Muscle, Skeletal/physiology , Muscle, Skeletal/metabolism , Muscular Dystrophy, Duchenne/genetics , Muscular Dystrophy, Duchenne/physiopathology , Running/physiologyABSTRACT
Nuclear receptor subfamily 5 group A member 1 (NR5A1) encodes steroidogenic factor 1 (SF1), a key regulatory factor that determines gonadal development and coordinates endocrine functions. Here, we have established a stem cell-based model of human gonadal development and applied it to evaluate the effects of NR5A1 during the transition from bipotential gonad to testicular cells. We combined directed differentiation of human induced pluripotent stem cells (46,XY) with activation of endogenous NR5A1 expression by conditionally-inducible CRISPR activation. The resulting male gonadal-like cells expressed several Sertoli cell transcripts, secreted anti-Müllerian hormone and responded to follicle-stimulating hormone by producing sex steroid intermediates. These characteristics were not induced without NR5A1 activation. A total of 2691 differentially expressed genetic elements, including both coding and non-coding RNAs, were detected immediately following activation of NR5A1 expression. Of those, we identified novel gonad-related putative NR5A1 targets, such as SCARA5, which we validated also by immunocytochemistry. In addition, NR5A1 activation was associated with dynamic expression of multiple gonad- and infertility-related differentially expressed genes. In conclusion, by combining targeted differentiation and endogenous activation of NR5A1 we have for the first time, been able to examine in detail the effects of NR5A1 in early human gonadal cells. The model and results obtained provide a useful resource for future investigations exploring the causative reasons for gonadal dysgenesis and infertility in humans.
Subject(s)
Induced Pluripotent Stem Cells , Infertility , Humans , Male , Steroidogenic Factor 1/genetics , Steroidogenic Factor 1/metabolism , Mutation , Induced Pluripotent Stem Cells/metabolism , Gonads/metabolism , Scavenger Receptors, Class A/geneticsABSTRACT
BACKGROUND & AIMS: Mutations in the APC gene and other genes in the Wnt signaling pathway contribute to development of colorectal carcinomas. R-spondins (RSPOs) are secreted proteins that amplify Wnt signaling in intestinal stem cells. Alterations in RSPO genes have been identified in human colorectal tumors. We studied the effects of RSPO1 overexpression in ApcMin/+ mutant mice. METHODS: An adeno associated viral vector encoding RSPO1-Fc fusion protein, or control vector, was injected into ApcMin/+mice. Their intestinal crypts were isolated and cultured as organoids. which were incubated with or without RSPO1-Fc and an inhibitor of transforming growth factor beta receptor (TGFBR). Livers were collected from mice and analyzed by immunohistochemistry. Organoids and adenomas were analyzed by quantitative reverse-transcription PCR, single cell RNA sequencing, and immunohistochemistry. RESULTS: Intestines from Apc+/+ mice injected with the vector encoding RSPO1-Fc had significantly deeper crypts, longer villi, with increased EdU labeling, indicating increased proliferation of epithelial cells, in comparison to mice given control vector. AAV-RSPO1-Fc-transduced ApcMin/+ mice also developed fewer and smaller intestinal tumors and had significantly longer survival times. Adenomas of ApcMin/+ mice injected with the RSPO1-Fc vector showed a rapid increase in apoptosis and in the expression of Wnt target genes, followed by reduced expression of messenger RNAs and proteins regulated by the Wnt pathway, reduced cell proliferation, and less crypt branching than adenomas of mice given the control vector. Addition of RSPO1 reduced the number of adenoma organoids derived from ApcMin/+ mice and suppressed expression of Wnt target genes but increased phosphorylation of SMAD2 and transcription of genes regulated by SMAD. Inhibition of TGFBR signaling in organoids stimulated with RSPO1-Fc restored organoid formation and expression of genes regulated by Wnt. The TGFBR inhibitor restored apoptosis in adenomas from ApcMin/+ mice expressing RSPO1-Fc back to the same level as in the adenomas from mice given the control vector. CONCLUSIONS: Expression of RSPO1 in ApcMin/+ mice increases apoptosis and reduces proliferation and Wnt signaling in adenoma cells, resulting in development of fewer and smaller intestinal tumors and longer mouse survival. Addition of RSPO1 to organoids derived from adenomas inhibits their growth and promotes proliferation of intestinal stem cells that retain the APC protein; these effects are reversed by TGFB inhibitor. Strategies to increase the expression of RSPO1 might be developed for the treatment of intestinal adenomas.
Subject(s)
Adenoma/pathology , Intestinal Neoplasms/pathology , Thrombospondins/metabolism , Transforming Growth Factor beta/physiology , Wnt Signaling Pathway/physiology , Adenoma/etiology , Animals , Disease Models, Animal , Intestinal Neoplasms/etiology , Mice , OrganoidsABSTRACT
INTRODUCTION: In postmenopausal osteoporosis, hormonal changes lead to increased bone turnover and metabolic alterations including increased fat mass and insulin resistance. Activin type IIB receptors bind several growth factors of the TGF-ß superfamily and have been demonstrated to increase muscle and bone mass. We hypothesized that ActRIIB-Fc treatment could improve bone and muscle mass, inhibit fat accumulation, and restore metabolic alterations in an ovariectomy (OVX) model of postmenopausal osteoporosis. MATERIALS AND METHODS: Female C57Bl/6 N mice were subjected to SHAM or OVX procedures and received intraperitoneal injections of either PBS or ActRIIB-Fc (5 mg/kg) once weekly for 7 weeks. Glucose and insulin tolerance tests (GTT and ITT, respectively) were performed at 7 and 8 weeks, respectively. Bone samples were analyzed with micro-computed tomography imaging, histomorphometry, and quantitative RT-PCR. RESULTS: Bone mass decreased in OVX PBS mice compared to the SHAM PBS group but ActRIIB-Fc was able to prevent these changes as shown by µCT and histological analyses. This was due to decreased osteoclast numbers and function demonstrated by histomorphometric and qRT-PCR analyses. OVX induced adipocyte hypertrophy that was rescued by ActRIIB-Fc, which also decreased systemic adipose tissue accumulation. OVX itself did not affect glucose levels in GTT but ActRIIB-Fc treatment resulted in impaired glucose clearance in both SHAM and OVX groups. OVX induced mild insulin resistance in ITT but ActRIIB-Fc treatment did not affect this. CONCLUSION: Our results reinforce the potency of ActRIIB-Fc as a bone-enhancing agent but also bring new insight into the metabolic effects of ActRIIB-Fc in normal and OVX mice.
Subject(s)
Activin Receptors, Type II , Bone Diseases, Metabolic , Insulin Resistance , Osteoporosis, Postmenopausal , Activin Receptors, Type II/therapeutic use , Adipose Tissue , Animals , Female , Glucose , Humans , Mice , Mice, Inbred C57BL , Ovariectomy , X-Ray MicrotomographyABSTRACT
Blocking of myostatin and activins effectively counteracts muscle atrophy. However, the potential interaction with physical inactivity and fasting in the regulation of muscle protein synthesis is poorly understood. We used blockade of myostatin and activins by recombinant adeno-associated virus (rAAV)-mediated follistatin (FS288) overexpression in mouse tibialis anterior muscle. To investigate the effects on muscle protein synthesis, muscles were collected 7 days after rAAV-injection in the nighttime or in the daytime representing high and low levels of activity and feeding, respectively, or after overnight fasting, refeeding, or ad libitum feeding. Muscle protein synthesis was increased by FS288 independent of the time of the day or the feeding status. However, the activation of mTORC1 signaling by FS288 was attenuated in the daytime and by overnight fasting. FS288 also increased the amount of mTOR colocalized with lysosomes, but did not alter their localization toward the sarcolemma. This study shows that FS288 gene delivery increases muscle protein synthesis largely independent of diurnal fluctuations in physical activity and food intake or feeding status, overriding the physiological signals. This is important for eg cachectic and sarcopenic patients with reduced physical activity and appetite. The FS288-induced increase in mTORC1 signaling and protein synthesis may be in part driven by increased amount of mTOR colocalized with lysosomes, but not by their localization toward sarcolemma.
Subject(s)
Fasting/physiology , Follistatin/genetics , Genetic Therapy , Muscle Proteins/biosynthesis , Muscular Atrophy/therapy , Physical Conditioning, Animal , Animals , Circadian Rhythm/physiology , Dependovirus/genetics , Energy Metabolism , JNK Mitogen-Activated Protein Kinases/metabolism , Male , Mechanistic Target of Rapamycin Complex 1/physiology , Mice , Mice, Inbred C57BLABSTRACT
BACKGROUND: Primary diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is based on detection of virus RNA in nasopharyngeal swab samples. In addition, analysis of humoral immunity against SARS-CoV-2 has an important role in viral diagnostics and seroprevalence estimates. METHODS: We developed and optimized an enzyme immunoassays (EIA) using SARS-CoV-2 nucleoprotein (N), S1 and receptor binding domain (RBD) of the viral spike protein, and N proteins from SARS, Middle East respiratory syndrome (MERS), and 4 low-pathogenic human CoVs. Neutralizing antibody activity was compared with SARS-CoV-2 IgG, IgA, and IgM EIA results. RESULTS: The sensitivity of EIA for detecting immune response in COVID-19 patients (n = 101) was 77% in the acute phase and 100% in the convalescent phase of SARS-CoV-2 infection when N and RBD were used as antigens in IgG and IgA specific EIAs. SARS-CoV-2 infection significantly increased humoral immune responses against the 229E and NL63 N proteins. S1 and RBD-based EIA results had a strong correlation with microneutralization test results. CONCLUSIONS: The data indicate a combination of SARS-CoV-2 S1 or RBD and N proteins and analysis of IgG and IgA immunoglobulin classes in sera provide an excellent basis for specific and sensitive serological diagnostics of COVID-19.
Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/immunology , Immunoglobulin A/blood , Immunoglobulin G/blood , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , Humans , Immunoenzyme Techniques , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Immunoglobulin M/blood , Immunoglobulin M/immunology , Neutralization Tests , Phosphoproteins/immunology , SARS-CoV-2/immunology , Sensitivity and SpecificityABSTRACT
BACKGROUND: Activins are members of the transforming growth factor-ß superfamily implicated in the pathogenesis of several immunoinflammatory disorders. Based on our previous studies demonstrating that overexpression of activin-A in murine lung causes pathology sharing key features of coronavirus disease 2019 (COVID-19), we hypothesized that activins and their natural inhibitor follistatin might be particularly relevant to COVID-19 pathophysiology. METHODS: Activin-A, activin-B, and follistatin were retrospectively analyzed in 574 serum samples from 263 COVID-19 patients hospitalized in 3 independent centers, and compared with demographic, clinical, and laboratory parameters. Optimal scaling with ridge regression was used to screen variables and establish a prediction model. RESULT: The activin/follistatin axis was significantly deregulated during the course of COVID-19, correlated with severity and independently associated with mortality. FACT-CLINYCoD, a scoring system incorporating follistatin, activin-A, activin-B, C-reactive protein, lactate dehydrogenase, intensive care unit admission, neutrophil/lymphocyte ratio, age, comorbidities, and D-dimers, efficiently predicted fatal outcome (area under the curve [AUC], 0.951; 95% confidence interval, .919-.983; P <10-6). Two validation cohorts indicated similar AUC values. CONCLUSIONS: This study demonstrates a link between activin/follistatin axis and COVID-19 mortality and introduces FACT-CLINYCoD, a novel pathophysiology-based tool that allows dynamic prediction of disease outcome, supporting clinical decision making.
Subject(s)
Activins/blood , COVID-19/blood , COVID-19/mortality , Follistatin/blood , SARS-CoV-2 , Aged , Biomarkers , COVID-19/physiopathology , Cohort Studies , Decision Support Techniques , Female , Greece/epidemiology , Hospital Mortality , Humans , Male , Middle Aged , Retrospective StudiesABSTRACT
Signaling through activin receptors regulates skeletal muscle mass and activin receptor 2B (ACVR2B) ligands are also suggested to participate in myocardial infarction (MI) pathology in the heart. In this study, we determined the effect of systemic blockade of ACVR2B ligands on cardiac function in experimental MI, and defined its efficacy to revert muscle wasting in ischemic heart failure (HF). Mice were treated with soluble ACVR2B decoy receptor (ACVR2B-Fc) to study its effect on post-MI cardiac remodeling and on later HF. Cardiac function was determined with echocardiography, and myocardium analyzed with histological and biochemical methods for hypertrophy and fibrosis. Pharmacological blockade of ACVR2B ligands did not rescue the heart from ischemic injury or alleviate post-MI remodeling and ischemic HF. Collectively, ACVR2B-Fc did not affect cardiomyocyte hypertrophy, fibrosis, angiogenesis, nor factors associated with cardiac regeneration except modification of certain genes involved in metabolism or cell growth/survival. ACVR2B-Fc, however, was able to reduce skeletal muscle wasting in chronic ischemic HF, accompanied by reduced LC3II as a marker of autophagy and increased mTOR signaling and Cited4 expression as markers of physiological hypertrophy in quadriceps muscle. Our results ascertain pharmacological blockade of ACVR2B ligands as a possible therapy for skeletal muscle wasting in ischemic HF. Pharmacological blockade of ACVR2B ligands preserved myofiber size in ischemic HF, but did not compromise cardiac function nor exacerbate cardiac remodeling after ischemic injury.
Subject(s)
Activin Receptors, Type II/antagonists & inhibitors , Disease Models, Animal , Heart/physiology , Muscular Atrophy/prevention & control , Myocardial Ischemia/complications , Transcription Factors/metabolism , Ventricular Remodeling/physiology , Activin Receptors, Type II/metabolism , Animals , Male , Mice , Mice, Inbred C57BL , Muscular Atrophy/etiology , Muscular Atrophy/metabolism , Muscular Atrophy/pathology , Signal Transduction , Transcription Factors/geneticsABSTRACT
RATIONALE: Although many familial cases of pulmonary arterial hypertension exhibit an autosomal dominant mode of inheritance with the majority having mutations in essential constituents of the BMP (bone morphogenetic protein) signaling, the specific contribution of the long-term loss of signal transduction triggered by the BMPR2 (type 2 BMP receptor) remains poorly characterized. OBJECTIVE: To investigate the role of BMP9, the main ligand of ALK1 (Activin receptor-like kinase 1)/BMPR2 heterocomplexes, in pulmonary hypertension. METHOD AND RESULTS: The absence of BMP9 in Bmp9-/- mice and its inhibition in C57BL/6 mice using neutralizing anti-BMP9 antibodies substantially prevent against chronic hypoxia-induced pulmonary hypertension judged by right ventricular systolic pressure measurement, right ventricular hypertrophy, and pulmonary distal arterial muscularization. In agreement with these observations, we found that the BMP9/BMP10 ligand trap ALK1ECD administered in monocrotaline or Sugen/hypoxia (SuHx) rats substantially attenuate proliferation of pulmonary vascular cells, inflammatory cell infiltration, and regresses established pulmonary hypertension in rats. Our data obtained in human pulmonary endothelial cells derived from controls and pulmonary arterial hypertension patients indicate that BMP9 can affect the balance between endothelin-1, apelin, and adrenomedullin. We reproduced these in vitro observations in mice chronically exposed to hypoxia, with Bmp9-/- mice exhibiting lower mRNA levels of the vasoconstrictor peptide ET-1 (endothelin-1) and higher levels of the 2 potent vasodilator factors apelin and ADM (adrenomedullin) compared with Bmp9+/+ littermates. CONCLUSIONS: Taken together, our data indicate that the loss of BMP9, by deletion or inhibition, has beneficial effects against pulmonary hypertension onset and progression.
Subject(s)
Growth Differentiation Factor 2/antagonists & inhibitors , Hypertension, Pulmonary/prevention & control , Activin Receptors, Type II/pharmacology , Animals , Cells, Cultured , Endothelin-1/genetics , Growth Differentiation Factor 2/physiology , Humans , Hypoxia/complications , Male , Mice , Mice, Inbred C57BL , Rats , Rats, WistarABSTRACT
Systemic skin-selective therapeutics would be a major advancement in the treatment of diseases affecting the entire skin, such as recessive dystrophic epidermolysis bullosa (RDEB), which is caused by mutations in the COL7A1 gene and manifests in transforming growth factor-ß (TGF-ß)-driven fibrosis and malignant transformation. Homing peptides containing a C-terminal R/KXXR/K motif (C-end rule [CendR] sequence) activate an extravasation and tissue penetration pathway for tumor-specific drug delivery. We have previously described a homing peptide CRKDKC (CRK) that contains a cryptic CendR motif and homes to angiogenic blood vessels in wounds and tumors, but it cannot penetrate cells or tissues. In this study, we demonstrate that removal of the cysteine from CRK to expose the CendR sequence confers the peptide novel ability to home to normal skin. Fusion of the truncated CRK (tCRK) peptide to the C terminus of an extracellular matrix protein decorin (DCN), a natural TGF-ß inhibitor, resulted in a skin-homing therapeutic molecule (DCN-tCRK). Systemic DCN-tCRK administration in RDEB mice led to inhibition of TGF-ß signaling in the skin and significant improvement in the survival of RDEB mice. These results suggest that DCN-tCRK has the potential to be utilized as a novel therapeutic compound for the treatment of dermatological diseases such as RDEB.
Subject(s)
Epidermolysis Bullosa/etiology , Epidermolysis Bullosa/metabolism , Peptides/metabolism , Protein Interaction Domains and Motifs , Animals , Biomarkers , Disease Models, Animal , Epidermolysis Bullosa/pathology , Fibrosis , Immunohistochemistry , Mice , Mice, Knockout , Neuropilin-1/metabolism , Peptides/chemistry , Peptides/pharmacology , Protein Binding , Recombinant Fusion Proteins/pharmacology , Skin/drug effects , Skin/metabolism , Transforming Growth Factor beta/metabolism , Wound Healing/drug effectsABSTRACT
Aberrant activation of signalling pathways has been postulated to promote age related changes in skeletal muscle. Cell signalling activation requires not only the expression of ligands and receptors but also an appropriate environment that facilitates their interaction. Here we first examined the expression of SULF1/SULF2 and members of RTK (receptor tyrosine kinase) and the Wnt family in skeletal muscle of normal and a mouse model of accelerated ageing. We show that SULF1/SULF2 and these signalling components, a feature of early muscle development are barely detectable in early postnatal muscle. Real time qPCR and immunocytochemical analysis showed gradual but progressive up-regulation of SULF1/SULF2 and RTK/Wnt proteins not only in the activated satellite cells but also on muscle fibres that gradually increased with age. Satellite cells on isolated muscle fibres showed spontaneous in vivo satellite cell activation and progressive reduction in proliferative potential and responsiveness to HGF (hepatocyte growth factor) and dysregulated myogenic differentiation with age. Finally, we show that SULF1/SULF2 and RTK/Wnt signalling components are expressed in progeric mouse muscles at earlier stage but their expression is attenuated by an intervention that promotes muscle repair and growth.
Subject(s)
Cell Differentiation , Muscle, Skeletal/growth & development , Satellite Cells, Skeletal Muscle/metabolism , Signal Transduction , Animals , Cells, Cultured , Male , Mice , Mice, Inbred C57BL , Muscle, Skeletal/cytology , Muscle, Skeletal/metabolism , Myoblasts/cytology , Myoblasts/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , Satellite Cells, Skeletal Muscle/cytology , Sulfatases/genetics , Sulfatases/metabolism , Sulfotransferases/genetics , Sulfotransferases/metabolism , Wnt Proteins/metabolismABSTRACT
Activin A and myostatin, members of the transforming growth factor (TGF)-ß superfamily of secreted factors, are potent negative regulators of muscle growth, but their contribution to myocardial ischemia-reperfusion (IR) injury is not known. The aim of this study was to investigate if activin 2B (ACVR2B) receptor ligands contribute to myocardial IR injury. Mice were treated with soluble ACVR2B decoy receptor (ACVR2B-Fc) and subjected to myocardial ischemia followed by reperfusion for 6 or 24 h. Systemic blockade of ACVR2B ligands by ACVR2B-Fc was protective against cardiac IR injury, as evidenced by reduced infarcted area, apoptosis, and autophagy and better preserved LV systolic function following IR. ACVR2B-Fc modified cardiac metabolism, LV mitochondrial respiration, as well as cardiac phenotype toward physiological hypertrophy. Similar to its protective role in IR injury in vivo, ACVR2B-Fc antagonized SMAD2 signaling and cell death in cardiomyocytes that were subjected to hypoxic stress. ACVR2B ligand myostatin was found to exacerbate hypoxic stress. In addition to acute cardioprotection in ischemia, ACVR2B-Fc provided beneficial effects on cardiac function in prolonged cardiac stress in cardiotoxicity model. By blocking myostatin, ACVR2B-Fc potentially reduces cardiomyocyte death and modifies cardiomyocyte metabolism for hypoxic conditions to protect the heart from IR injury.
Subject(s)
Myocardial Reperfusion Injury/metabolism , Myocardium/metabolism , Smad2 Protein/metabolism , Activin Receptors, Type II/genetics , Activin Receptors, Type II/metabolism , Animals , Male , Mice , Mice, Inbred C57BL , Myocytes, Cardiac/metabolism , Myostatin/metabolism , Signal Transduction/genetics , Signal Transduction/physiology , Smad2 Protein/genetics , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Cancer-associated cachexia reduces survival, which has been attenuated by blocking the activin receptor type 2B (ACVR2B) ligands in mice. The purpose of this study was to unravel the underlying physiology and novel cachexia biomarkers by use of the colon-26 (C26) carcinoma model of cancer cachexia. Male BALB/c mice were subcutaneously inoculated with C26 cancer cells or vehicle control. Tumor-bearing mice were treated with vehicle (C26+PBS) or soluble ACVR2B either before (C26+sACVR/b) or before and after (C26+sACVR/c) tumor formation. Skeletal muscle and serum metabolomics analysis was conducted by gas chromatography-mass spectrometry. Cancer altered various biologically functional groups representing 1) amino acids, 2) energy sources, and 3) nucleotide-related intermediates. Muscle metabolomics revealed increased content of free phenylalanine in cancer that strongly correlated with the loss of body mass within the last 2 days of the experiment. This correlation was also detected in serum. Decreased ribosomal RNA content and phosphorylation of a marker of pyrimidine synthesis revealed changes in nucleotide metabolism in cancer. Overall, the effect of the experimental C26 cancer predominated over blocking ACVR2B ligands in both muscle and serum. However, the level of methyl phosphate, which was decreased in muscle in cancer, was restored by sACVR2B-Fc treatment. In conclusion, experimental cancer affected muscle and blood metabolomes mostly independently of blocking ACVR2B ligands. Of the affected metabolites, we have identified free phenylalanine as a promising biomarker of muscle atrophy or cachexia. Finally, the decreased capacity for pyrimidine nucleotide and protein synthesis in tumor-bearing mice opens up new avenues in cachexia research.
Subject(s)
Activin Receptors, Type II/antagonists & inhibitors , Cachexia/metabolism , Colonic Neoplasms/metabolism , Metabolome/physiology , Muscle, Skeletal/metabolism , Amino Acids/metabolism , Animals , Cachexia/etiology , Cell Line, Tumor , Colonic Neoplasms/complications , Immunoglobulin Fc Fragments/pharmacology , Male , Metabolic Networks and Pathways , Metabolome/drug effects , Mice , Muscle, Skeletal/drug effects , Organophosphates/metabolism , Phenylalanine/metabolism , Protein Biosynthesis/drug effects , Protein Biosynthesis/physiology , Pyrimidine Nucleotides/metabolism , Recombinant ProteinsABSTRACT
OBJECTIVE: Evaluation of circulating tumor markers in ovarian cancer is crucial for optimal patient care. The goal of this study was to verify the most accurate circulating tumor markers for the diagnosis and follow-up of adult-type granulosa cell tumors (AGCTs). METHODS: The levels of circulating human epididymis protein 4 (HE4) and carbohydrate antigen 125 (CA125), together with AGCT markers inhibin B and anti-Müllerian hormone (AMH), were measured in 135 samples from AGCT patients, 37 epithelial ovarian carcinoma (EOC) patients, and 40 endometrioma (ENDO) patients. The levels were plotted with receiver operating characteristic (ROC) graphs, and the area under the curves (AUC) of the different markers were calculated and compared. RESULTS: HE4 levels were significantly lower in AGCTs than in EOCs (p<0.0001). CA125 levels were above 35IU/l in 25% of AGCT patients and 47.5% of ENDO patients, whereas inhibin B and AMH levels were elevated only in patients with AGCTs. In the AUC comparison analyses, inhibin B alone was sufficient to differentiate AGCT from EOC. In differentiating AGCT from ENDO, inhibin B and AMH performed similarly, and the combination of inhibin B and AMH increased the accuracy compared to either marker alone (sensitivity, 100%; specificity, 93%). Among AGCT patients, inhibin B was the best marker for detecting the presence of AGCT. CONCLUSIONS: HE4 and CA125 levels were low in AGCTs, and inhibin B was the most accurate circulating biomarker in distinguishing AGCTs from EOCs and from ENDOs. Inhibin B was also the best single marker for AGCT follow-up.
Subject(s)
Biomarkers, Tumor/blood , Endometriosis/blood , Endometriosis/diagnosis , Granulosa Cell Tumor/blood , Granulosa Cell Tumor/diagnosis , Neoplasms, Glandular and Epithelial/blood , Neoplasms, Glandular and Epithelial/diagnosis , Adult , Aftercare , Aged , Aged, 80 and over , Anti-Mullerian Hormone/blood , Area Under Curve , CA-125 Antigen/blood , Diagnosis, Differential , Female , Humans , Inhibins/blood , Middle Aged , Proteins/metabolism , ROC Curve , WAP Four-Disulfide Core Domain Protein 2ABSTRACT
Activins are members of the transforming growth factor-beta (TGF-ß) superfamily of cytokines. They play critical roles in the onset of acute and chronic inflammatory responses. The aim of this study was to investigate how activin inhibition affects acute kidney injury and inflammation after transplantation. The study was carried out in kidney transplantation and renal ischemia-reperfusion models in the rat. Soluble activin type 2 receptor (sActRIIB-Fc) was used to inhibit activin signaling. Transplantation groups were as follows: (i) cyclosporine A (CsA) (ii) CsA + sActRIIB-Fc, (iii) CsA+ inactive protein control Fc-G1. IRI groups were as follows: (i) no treatment, (ii) sActRIIB-Fc. Serum activin B concentration was significantly elevated after transplantation and IRI, whereas activin A was produced locally in renal allografts. Activin inhibition efficiently limited neutrophil, macrophage, and dendritic cell infiltration to the allografts measured 72 h after transplantation. In addition, sActRIIB-Fc treatment modulated serum cytokine response after transplantation and reduced the early accumulation of fibroblasts in the graft interstitium. In conclusion activin inhibition reduces the innate immune response early after renal transplantation in the rat. It also limits the accumulation of fibroblasts in the graft suggesting that activins may be involved in the fibrogenic signaling already early after kidney transplantation.
Subject(s)
Activins/antagonists & inhibitors , Allografts/immunology , Immunity, Innate , Kidney Transplantation , Kidney/immunology , Activins/metabolism , Animals , Cytokines/metabolism , Enzyme-Linked Immunosorbent Assay , Fibroblasts/metabolism , Humans , Inflammation , Male , Pilot Projects , Rats , Rats, Wistar , Renal Insufficiency/surgery , Reperfusion Injury , Signal Transduction , Time Factors , Transforming Growth Factor beta/metabolism , Transplantation, HomologousABSTRACT
BACKGROUND: Inhibition of activin/myostatin pathway has emerged as a novel approach to increase muscle mass and bone strength. Duchenne muscular dystrophy (DMD) is a neuromuscular disorder that leads to progressive muscle degeneration and also high incidence of fractures. The aim of our study was to test whether inhibition of activin receptor IIB ligands with or without exercise could improve bone strength in the mdx mouse model for DMD. METHODS: Thirty-two mdx mice were divided to running and non-running groups and to receive either PBS control or soluble activin type IIB-receptor (ActRIIB-Fc) once weekly for 7 weeks. RESULTS: Treatment of mdx mice with ActRIIB-Fc resulted in significantly increased body and muscle weights in both sedentary and exercising mice. Femoral µCT analysis showed increased bone volume and trabecular number (BV/TV +80%, Tb.N +70%, P < 0.05) in both ActRIIB-Fc treated groups. Running also resulted in increased bone volume and trabecular number in PBS-treated mice. However, there was no significant difference in trabecular bone structure or volumetric bone mineral density between the ActRIIB-Fc and ActRIIB-Fc-R indicating that running did not further improve bone structure in ActRIIB-Fc-treated mice. ActRIIB-Fc increased bone mass also in vertebrae (BV/TV +20%, Tb.N +30%, P < 0.05) but the effects were more modest. The number of osteoclasts was decreased in histological analysis and the expression of several osteoblast marker genes was increased in ActRIIB-Fc treated mice suggesting decreased bone resorption and increased bone formation in these mice. Increased bone mass in femurs translated into enhanced bone strength in biomechanical testing as the maximum force and stiffness were significantly elevated in ActRIIB-Fc-treated mice. CONCLUSIONS: Our results indicate that treatment of mdx mice with the soluble ActRIIB-Fc results in a robust increase in bone mass, without any additive effect by voluntary running. Thus ActRIIB-Fc could be an attractive option in the treatment of musculoskeletal disorders.
Subject(s)
Activin Receptors, Type II/therapeutic use , Bone Density/drug effects , Muscular Dystrophy, Animal/drug therapy , Muscular Dystrophy, Duchenne , Animals , Bone Resorption/pathology , Bone Resorption/prevention & control , Bone and Bones/drug effects , Bone and Bones/pathology , Combined Modality Therapy , Disease Models, Animal , Drug Evaluation, Preclinical , Male , Mice , Mice, Inbred C57BL , Mice, Inbred mdx , Muscle, Skeletal/drug effects , Muscle, Skeletal/pathology , Muscular Dystrophy, Animal/pathology , Muscular Dystrophy, Animal/physiopathology , Muscular Dystrophy, Animal/therapy , Organ Size/drug effects , Osteoblasts/drug effects , Osteoblasts/pathology , Osteoclasts/drug effects , Osteoclasts/pathology , Physical Conditioning, Animal , SolubilityABSTRACT
In the majority of microsatellite-stable colorectal cancers (CRCs), an initiating mutation occurs in the adenomatous polyposis coli (APC) or ß-catenin gene, activating the ß-catenin/TCF pathway. The progression of resulting adenomas is associated with oncogenic activation of KRas and inactivation of the p53 and TGF-ß/Smad functions. Most established CRC cell lines contain mutations in the TGF-ß/Smad pathway, but little is known about the function of TGF-ß in the early phases of intestinal tumorigenesis. We used mouse and human ex vivo 3D intestinal organoid cultures and in vivo mouse models to study the effect of TGF-ß on the Lgr5(+) intestinal stem cells and their progeny in intestinal adenomas. We found that the TGF-ß-induced apoptosis in Apc-mutant organoids, including the Lgr5(+) stem cells, was mediated by up-regulation of the BH3-only proapoptotic protein Bcl-2-like protein 11 (Bim). BH3-mimetic compounds recapitulated the effect of Bim not only in the adenomas but also in human CRC organoids that had lost responsiveness to TGF-ß-induced apoptosis. However, wild-type intestinal crypts were markedly less sensitive to TGF-ß than Apc-mutant adenomas, whereas the KRas oncogene increased resistance to TGF-ß via the activation of the Erk1/2 kinase pathway, leading to Bim down-regulation. Our studies identify Bim as a critical mediator of TGF-ß-induced apoptosis in intestinal adenomas and show that the common progression mutations modify Bim levels and sensitivity to TGF-ß during intestinal adenoma development.
Subject(s)
Adenoma/genetics , Apoptosis Regulatory Proteins/metabolism , Apoptosis/genetics , Gene Expression Regulation, Neoplastic/genetics , Intestinal Neoplasms/genetics , Membrane Proteins/metabolism , Proto-Oncogene Proteins/metabolism , Transforming Growth Factor beta/metabolism , Animals , Bcl-2-Like Protein 11 , Blotting, Western , Cells, Cultured , Chromatography, Gel , DNA Primers/genetics , Flow Cytometry , Humans , Mice , Microarray Analysis , Organoids/metabolism , Receptors, G-Protein-Coupled/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Stem Cells/metabolismABSTRACT
Autosomal dominant polycystic kidney disease (ADPKD), characterized by the formation of numerous kidney cysts, is caused by PKD1 or PKD2 mutations and affects 0.1% of the population. Although recent clinical studies indicate that reduction of cAMP levels slows progression of PKD, this finding has not led to an established safe and effective therapy for patients, indicating the need to find new therapeutic targets. The role of TGF-ß in PKD is not clearly understood, but nuclear accumulation of phosphorylated SMAD2/3 in cyst-lining cells suggests the involvement of TGF-ß signaling in this disease. In this study, we ablated the TGF-ß type 1 receptor (also termed activin receptor-like kinase 5) in renal epithelial cells of PKD mice, which had little to no effect on the expression of SMAD2/3 target genes or the progression of PKD. Therefore, we investigated whether alternative TGF-ß superfamily ligands account for SMAD2/3 activation in cystic epithelial cells. Activins are members of the TGF-ß superfamily and drive SMAD2/3 phosphorylation via activin receptors, but activins have not been studied in the context of PKD. Mice with PKD had increased expression of activin ligands, even at early stages of disease. In addition, treatment with a soluble activin receptor IIB fusion (sActRIIB-Fc) protein, which acts as a soluble trap to sequester activin ligands, effectively inhibited cyst formation in three distinct mouse models of PKD. These data point to activin signaling as a key pathway in PKD and a promising target for therapy.
Subject(s)
Activins/antagonists & inhibitors , Polycystic Kidney Diseases/prevention & control , Signal Transduction , Animals , Disease Progression , Epithelial Cells , Female , Kidney/cytology , Male , Mice , Polycystic Kidney Diseases/etiology , Recombinant Fusion Proteins/pharmacology , Smad2 Protein/physiology , Smad3 Protein/physiology , Time FactorsABSTRACT
Activin-A and activin-B, members of the TGF-ß superfamily, are regulators of reproductive functions, inflammation and wound healing. These dimeric molecules regulate various cellular activities such as proliferation, migration and suvival. Malignant mesothelioma is an asbestos exposure related tumor affecting mainly pleura and it usually has a dismal prognosis. Here, we demonstrate that both activin-A and -B are abundantly expressed in mesothelioma tumor tissue as well as in cultured primary and established mesothelioma cells. Migratory and invasive mesothelioma cells were also found to have attenuated activation of the Smad2/3 pathway in response to activins. Migration and invasive growth of the cells in three-dimentional matrix was prevented by inhibition of activin activity using a soluble activin receptor 2B (sActR2B-Fc). This was associated with decreased ERK activity. Furthermore, migration and invasive growth was significantly inhibited by blocking ERK phosphorylation. Mesothelioma tumors are locally invasive and our results clearly suggest that acivins have a tumor-promoting function in mesothelioma through increasing expression and switching from canonical Smad3 pathway to non-canonical ERK pathway signaling. Blocking activin activity offers a new therapeutic approach for inhibition of mesothelioma invasive growth.
Subject(s)
Activins/metabolism , Cell Movement , Extracellular Signal-Regulated MAP Kinases/metabolism , Lung Neoplasms/metabolism , Mesothelioma/metabolism , Smad3 Protein/metabolism , Activin Receptors, Type I/metabolism , Activin Receptors, Type II/metabolism , Activins/genetics , Aged , Enzyme Activation , Female , Gene Expression , Humans , Lung Neoplasms/pathology , MAP Kinase Signaling System , Male , Mesothelioma/pathology , Mesothelioma, Malignant , Middle Aged , Neoplasm InvasivenessABSTRACT
Follistatin, a physiological inhibitor of myostatin, induces a dramatic increase in skeletal muscle mass, requiring the type 1 IGF-I receptor/Akt/mTOR pathway. The aim of the present study was to investigate the role of IGF-I and insulin, two ligands of the IGF-I receptor, in the follistatin hypertrophic action on skeletal muscle. In a first step, we showed that follistatin increases muscle mass while being associated with a downregulation of muscle IGF-I expression. In addition, follistatin retained its full hypertrophic effect toward muscle in hypophysectomized animals despite very low concentrations of circulating and muscle IGF-I. Furthermore, follistatin did not increase muscle sensitivity to IGF-I in stimulating phosphorylation of Akt but, surprisingly, decreased it once hypertrophy was present. Taken together, these observations indicate that increased muscle IGF-I production or sensitivity does not contribute to the muscle hypertrophy caused by follistatin. Unlike low IGF-I, low insulin, as obtained by streptozotocin injection, attenuated the hypertrophic action of follistatin on skeletal muscle. Moreover, the full anabolic response to follistatin was restored in this condition by insulin but also by IGF-I infusion. Therefore, follistatin-induced muscle hypertrophy requires the activation of the insulin/IGF-I pathway by either insulin or IGF-I. When insulin or IGF-I alone is missing, follistatin retains its full anabolic effect, but when both are deficient, as in streptozotocin-treated animals, follistatin fails to stimulate muscle growth.