Endothelial Bmx tyrosine kinase activity is essential for myocardial hypertrophy and remodeling
Cardiac hypertrophy accompanies many forms of heart disease, including ischemic disease, hypertension, heart failure, and valvular disease, and it is a strong predictor of increased cardiovascular morbidity and mortality. Deletion of bone marrow kinase in chromosome X (Bmx), an arterial nonreceptor tyrosine kinase, has been shown to inhibit cardiac hypertrophy in mice. This finding raised the possibility of therapeutic use of Bmx tyrosine kinase inhibitors, which we have addressed here by analyzing cardiac hypertrophy in gene-targeted mice deficient in Bmx tyrosine kinase activity. We found that angiotensin II (Ang II)-induced cardiac hypertrophy is significantly reduced in mice deficient i…
VEGF-B-induced vascular growth leads to metabolic reprogramming and ischemia resistance in the heart
Abstract Angiogenic growth factors have recently been linked to tissue metabolism. We have used genetic gain‐ and loss‐of function models to elucidate the effects and mechanisms of action of vascular endothelial growth factor‐B (VEGF‐B) in the heart. A cardiomyocyte‐specific VEGF‐B transgene induced an expanded coronary arterial tree and reprogramming of cardiomyocyte metabolism. This was associated with protection against myocardial infarction and preservation of mitochondrial complex I function upon ischemia‐reperfusion. VEGF‐B increased VEGF signals via VEGF receptor‐2 to activate Erk1/2, which resulted in vascular growth. Akt and mTORC1 pathways were upregulated and AMPK downregulated, …
Effects of exhaustive stretch-shortening cycle exercise on muscle blood flow during exercise
Aim: The influence of exhaustive stretch-shortening cycle exercise (SSC) on skeletal muscle blood flow (BF) during exercise is currently unknown. Methods: Quadriceps femoris (QF) BF was measured in eight healthy men using positron emission tomography before and 3 days after exhaustive SSC exercise. The SSC protocol consisted of maximal and submaximal drop jumps with one leg. Needle biopsies of the vastus lateralis muscles were taken immediately and 2 days after SSC for muscle endothelial nitric oxide synthase (eNOS) and interleukin-1-beta (IL-1β) mRNA level determinations. Results: All subjects reported subjective muscle soreness after SSC (P < 0.001), which was well in line with a decre…
PROX1 transcription factor controls rhabdomyosarcoma growth, stemness, myogenic properties and therapeutic targets
Funding Information: ACKNOWLEDGMENTS. We would like to thank Dr. Tuomas Tammela and Dr. Monika Ehnmann for providing RMS cell lines and Dr. Jenny Högström for discussions and comments during the project. Kirsi Mattinen, Jefim Brodkin, Maxime Laird, Manon Gruchet, Ilse Paetau, Tanja Laakkonen, and Tapio Tainola are acknowledged for their excellent technical help. We also thank the Laboratory Animal Center at the University of Helsinki for expert animal care, the Biomedicum Imaging Unit for microscope support, the Biomedicum Functional Genomics Unit for the RNAseq experiments and the FIMM Technology Centre High Throughput Biomedicine for the drug sensitivity and resistance testing. Our first …
Prevention of chemotherapy-induced cachexia by ACVR2B ligand blocking has different effects on heart and skeletal muscle
Background Toxicity of chemotherapy on skeletal muscles and the heart may significantly contribute to cancer cachexia, mortality, and decreased quality of life. Doxorubicin (DOX) is an effective cytostatic agent, which unfortunately has toxic effects on many healthy tissues. Blocking of activin receptor type IIB (ACVR2B) ligands is an often used strategy to prevent skeletal muscle loss, but its effects on the heart are relatively unknown. Methods The effects of DOX treatment with or without pre-treatment with soluble ACVR2B-Fc (sACVR2B-Fc) were investigated. The mice were randomly assigned into one of the three groups: (1) vehicle (PBS)-treated controls, (2) DOX-treated mice (DOX), and (3) …
Lihassolurakenteen ja entsyymiaktiivisuuksien yhteydet isometriseen voimantuottoon, maksimijuoksunopeuteen sekä juoksun taloudellisuuteen
Riikka Kivelä: Lihassolurakenteen ja entsyymiaktiivisuuksien yhteydet isometriseen voimantuottoon, maksimijuoksunopeuteen sekä juoksun taloudellisuuteen. Tutkimuksen tarkoituksena oli selvittää lihaksen biokemiallisten ominaisuuksien (myosiinin raskasketjukoostumus, lihassolujakauma ja entsyymiaktiivisuudet) yhteyttä maksimivoimaan ja voimantuottonopeuteen, maksimijuoksunopeuteen sekä juoksun taloudellisuuteen eri nopeuksilla. Energiantuottoon vaikuttavista entsyymeistä tarkasteltiin kahden aerobisen (CS ja HAD) sekä kahden anaerobisen (PFK ja LDH) entsyymiaktiivisuuksia. Kymmenen Suomen parhaimmistoon kuuluvan keskimatkan (800-5000 metrin) miesjuoksijan juoksun taloudellisuutta mitattiin v…
VEGF-B gene therapy inhibits doxorubicin-induced cardiotoxicity by endothelial protection
Congestive heart failure is one of the leading causes of disability in long-term survivors of cancer. The anthracycline antibiotic doxorubicin (DOX) is used to treat a variety of cancers, but its utility is limited by its cumulative cardiotoxicity. As advances in cancer treatment have decreased cancer mortality, DOX-induced cardiomyopathy has become an increasing problem. However, the current means to alleviate the cardiotoxicity of DOX are limited. We considered that vascular endothelial growth factor-B (VEGF-B), which promotes coronary arteriogenesis, physiological cardiac hypertrophy, and ischemia resistance, could be an interesting candidate for prevention of DOX-induced cardiotoxicity …
Effects of fatiguing jumping exercise on mRNA expression of titin-complex proteins and calpains.
Eccentric exercise induced by electrostimulation increases mRNA expression of titin-complex proteins in rodent skeletal muscle. In this study, mRNA expression of titin, muscle LIM protein (MLP), cardiac ankyrin repeat protein (CARP), ankyrin repeat domain protein 2 (Ankrd2), diabetes-related ankyrin repeat protein (DARP), and calcium-activated proteinases, calpains, were investigated in human skeletal muscle after fatiguing jumping exercise. Fatiguing jumping exercise did not change mRNA expression of titin, DARP, calpain 1, or calpain 3. MLP, Ankrd2 and calpain 2 mRNA levels were increased 2 days postexercise. CARP mRNA level was already elevated 30 min and remained elevated 2 days postexe…
Liikunnan biotieteet : tiivistä yhteistyötä ja aktiivista vuoropuhelua
Liikunnan biotieteiden yhteistyö perustieteiden kanssa tiivistyy tulevaisuudessa entisestään, samoin aktiivinen vuoropuhelu liikunnan edistäjien kanssa. Liikunnan ylivertaiset terveysvaikutukset ovat lisänneet myös perustieteiden kiinnostusta selvittää liikunnan vaikutusmekanismeja, mikä tarjoaa mahdollisuuden win-win -yhteistyöhön. Liikuntafysiologian seuraavat merkittävät löydöt ovat odotettavissa mahdollisesti tutkimuksista, joissa uusien tutkimusmenetelmien avulla vertaillaan eri tyyppisen liikunnan vaikutuksia eri elimissä ja niiden välisessä vuorovaikutuksessa. nonPeerReviewed
Lipid droplet-associated proteins in high-fat fed mice with the effects of voluntary running and diet change
Abstract Objective The relation between lipid accumulation and influence of exercise on insulin sensitivity is not straightforward. A proper balance between lipid droplet synthesis, lipolysis, and oxidative metabolism would ensure low local intramyocellular fatty acid levels, thereby possibly protecting against lipotoxicity-associated insulin resistance. This study investigated whether the accumulation of triglycerides and lipid droplets in response to high availability of fatty acids after high-fat feeding would parallel the abundance of intramyocellular perilipin proteins, especially PLIN5. The effects on these variables after diet change or voluntary running exercise intervention in skel…
Effects of experimental type 1 diabetes and exercise training on angiogenic gene expression and capillarization in skeletal muscle.
Diabetes alters microvascular structure and function and is a major risk factor for cardiovascular diseases. In diabetic skeletal muscle, impaired angiogenesis and reduced VEGF-A expression have been observed, whereas in healthy muscle exercise is known to have opposite effects. We studied the effects of type 1 diabetes and combined exercise training on angiogenic mRNA expression and capillarization in mouse skeletal muscle. Microarray and real-time PCR analyses showed that diabetes altered the expression of several genes involved in angiogenesis. For example, levels of proangiogenic VEGF-A, VEGF-B, neuropilin-1, VEGFR-1, and VEGFR-2 were reduced and the levels of antiangiogenic thrombospon…
Systemic blockade of ACVR2B ligands protects myocardium from acute ischemia-reperfusion injury
Activin A and myostatin, members of the transforming growth factor (TGF)-β 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 fo…
Interrelationships between Muscle Structure, Muscle Strength, and Running Economy
The present study was designed to investigate possible differences in running economy (RE) among elite middle-distance runners by examining muscle structure and maximal isometric force (MVC).Ten young male runners ran at six different running speeds. During the running bouts, respiratory gases, and blood lactate were measured. Muscle biopsies were obtained from the vastus lateralis muscle for analyzing fiber type distribution, muscle fiber area, myosin heavy chain (MHC) composition, activities of a number of metabolic enzymes (citrate synthase, lactate dehydrogenase, phosphofruktokinase, and 3-hydroxyacyl-CoA-dehydrogenase), and titin isoforms.Energy expenditure (EE) increased linearly up t…
Long lasting high fat feeding increases the capillary density in the skeletal muscle of mice
Systemic blockade of ACVR2B ligands prevents chemotherapy-induced muscle wasting by restoring muscle protein synthesis without affecting oxidative capacity or atrogenes
AbstractDoxorubicin is a widely used and effective chemotherapy drug. However, cardiac and skeletal muscle toxicity of doxorubicin limits its use. Inhibiting myostatin/activin signalling can prevent muscle atrophy, but its effects in chemotherapy-induced muscle wasting are unknown. In the present study we investigated the effects of doxorubicin administration alone or combined with activin receptor ligand pathway blockade by soluble activin receptor IIB (sACVR2B-Fc). Doxorubicin administration decreased body mass, muscle size and bone mineral density/content in mice. However, these effects were prevented by sACVR2B-Fc administration. Unlike in many other wasting situations, doxorubicin indu…
Effects of acute exercise, exercise training, and diabetes on the expression of lymphangiogenic growth factors and lymphatic vessels in skeletal muscle.
Blood and lymphatic vessels together form the circulatory system, allowing the passage of fluids and molecules within the body. Recently we showed that lymphatic capillaries are also found in the capillary bed of skeletal muscle. Exercise is known to induce angiogenesis in skeletal muscle, but it is not known whether exercise has effects on lymphangiogenesis or lymphangiogenic growth factors. We studied lymphatic vessel density and expression of the main lymphangiogenic growth factors VEGF-C and VEGF-D and their receptor VEGFR-3 in response to acute running exercise and endurance exercise training in the skeletal muscle of healthy and diabetic mice. VEGF-C mRNA expression increased after t…
Altered REDD1, myostatin, and Akt/mTOR/FoxO/MAPK signaling in streptozotocin-induced diabetic muscle atrophy
Type 1 diabetes, if poorly controlled, leads to skeletal muscle atrophy, decreasing the quality of life. We aimed to search highly responsive genes in diabetic muscle atrophy in a common diabetes model and to further characterize associated signaling pathways. Mice were killed 1, 3, or 5 wk after streptozotocin or control. Gene expression of calf muscles was analyzed using microarray and protein signaling with Western blotting. We identified translational repressor protein REDD1 (regulated in development and DNA damage responses) that increased seven- to eightfold and was associated with muscle atrophy in diabetes. The diabetes-induced increase in REDD1 was confirmed at the protein level. …
Effects of Long-Term Physical Activity and BCAA Availability on the Subcellular Associations between Intramyocellular Lipids, Perilipins and PGC-1α
Cellular skeletal muscle lipid metabolism is of paramount importance for metabolic health, specifically through its connection to branched-chain amino acids (BCAA) metabolism and through its modulation by exercise. In this study, we aimed at better understanding intramyocellular lipids (IMCL) and their related key proteins in response to physical activity and BCAA deprivation. By means of confocal microscopy, we examined IMCL and the lipid droplet coating proteins PLIN2 and PLIN5 in human twin pairs discordant for physical activity. Additionally, in order to study IMCLs, PLINs and their association to peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) in cytosolic…
Effects of high-fat diet and physical activity on pyruvate dehydrogenase kinase-4 in mouse skeletal muscle
Abstract Background The expression of PDK4 is elevated by diabetes, fasting and other conditions associated with the switch from the utilization of glucose to fatty acids as an energy source. It is previously shown that peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a master regulator of energy metabolism, coactivates in cell lines pyruvate dehydrogenase kinase-4 (PDK4) gene expression via the estrogen-related receptor α (ERRα). We investigated the effects of long-term high-fat diet and physical activity on the expression of PDK4, PGC-1α and ERRα and the amount and function of mitochondria in skeletal muscle. Methods Insulin resistance was induced by a high-fat (HF) d…
NAD+ repletion with niacin counteracts cancer cachexia
AbstractCachexia is a debilitating wasting syndrome and highly prevalent comorbidity in cancer patients. It manifests especially with energy and mitochondrial metabolism aberrations that promote tissue wasting. We recently identified nicotinamide adenine dinucleotide (NAD+) loss to associate with muscle mitochondrial dysfunction in cancer hosts. In this study we confirm that depletion of NAD+ and downregulation of Nrk2, an NAD+ biosynthetic enzyme, are common features of severe cachexia in different mouse models. Testing NAD+ repletion therapy in cachectic mice reveals that NAD+ precursor, vitamin B3 niacin, efficiently corrects tissue NAD+ levels, improves mitochondrial metabolism and amel…
Gene expression centroids that link with low intrinsic aerobic exercise capacity and complex disease risk
A strong link exists between low aerobic exercise capacity and complex metabolic diseases. To probe this linkage, we utilized rat models of low and high intrinsic aerobic endurance running capacity that differ also in the risk for metabolic syndrome. We investigated in skeletal muscle gene-phenotype relationships that connect aerobic endurance capacity with metabolic disease risk factors. The study compared 12 high capacity runners (HCRs) and 12 low capacity runners (LCRs) from generation 18 of selection that differed by 615% for maximal treadmill endurance running capacity. On average, LCRs were heavier and had increased blood glucose, insulin, and triglycerides compared with HCRs. HCRs we…
Treating cachexia using soluble ACVR2B improves survival, alters mTOR localization, and attenuates liver and spleen responses.
Background Cancer cachexia increases morbidity and mortality, and blocking of activin receptor ligands has improved survival in experimental cancer. However, the underlying mechanisms have not yet been fully uncovered. Methods The effects of blocking activin receptor type 2 (ACVR2) ligands on both muscle and non‐muscle tissues were investigated in a preclinical model of cancer cachexia using a recombinant soluble ACVR2B (sACVR2B‐Fc). Treatment with sACVR2B‐Fc was applied either only before the tumour formation or with continued treatment both before and after tumour formation. The potential roles of muscle and non‐muscle tissues in cancer cachexia were investigated in order to understand th…
Muscle follistatin gene delivery increases muscle protein synthesis independent of periodical physical inactivity and fasting
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…
Molecular adaptations of voltage-gated sodium ion channel related proteins after fatiguing stretch-shortening cycle exercise
Dystrophin associated protein alpha-syntrophin is known to interact with voltage-gated sodium ion channel (NaCh). Dystrophin is known to be sensitive to eccentric muscle actions. For this reason, the function of the NaChs might also be affected. Molecular adaptations of dystrophin, alpha-syntrophin and NaChs were investigated after fatiguing stretch-shortening cycle (SSC) exercise, which consisted of unilateral jumps on a sledge apparatus. Muscle biopsies were taken from the vastus lateralis muscle of eight healthy subjects immediately after (IA) and 2 days after (2D) the exercise to analyze mRNA levels and immunohistochemical staining patterns. SSC exercise resulted in decreased isometric …
STAT5b is a key effector of NRG-1/ERBB4-mediated myocardial growth
The growth factor Neuregulin-1 (NRG-1) regulates myocardial growth and is currently under clinical investigation as a treatment for heart failure. Here, we demonstrate in several in vitro and in vivo models that STAT5b mediates NRG-1/EBBB4-stimulated cardiomyocyte growth. Genetic and chemical disruption of the NRG-1/ERBB4 pathway reduces STAT5b activation and transcription of STAT5b target genes Igf1, Myc, and Cdkn1a in murine cardiomyocytes. Loss of Stat5b also ablates NRG-1-induced cardiomyocyte hypertrophy. Dynamin-2 is shown to control the cell surface localization of ERBB4 and chemical inhibition of Dynamin-2 downregulates STAT5b activation and cardiomyocyte hypertrophy. In zebrafish e…