scholarly journals Troponin Variants as Markers of Skeletal Muscle Health and Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Monica Rasmussen ◽  
Jian-Ping Jin
Keyword(s):  
Skeletal Muscle ◽  
Troponin I ◽  
Striated Muscle ◽  
Troponin T ◽  
Muscle Quality ◽  
Striated Muscles ◽  
Thin Filaments ◽  
Age Related ◽  
Development And Aging ◽  
Regulation Of Muscle Contraction

Ca2+-regulated contractility is a key determinant of the quality of muscles. The sarcomeric myofilament proteins are essential players in the contraction of striated muscles. The troponin complex in the actin thin filaments plays a central role in the Ca2+-regulation of muscle contraction and relaxation. Among the three subunits of troponin, the Ca2+-binding subunit troponin C (TnC) is a member of the calmodulin super family whereas troponin I (TnI, the inhibitory subunit) and troponin T (TnT, the tropomyosin-binding and thin filament anchoring subunit) are striated muscle-specific regulatory proteins. Muscle type-specific isoforms of troponin subunits are expressed in fast and slow twitch fibers and are regulated during development and aging, and in adaptation to exercise or disuse. TnT also evolved with various alternative splice forms as an added capacity of muscle functional diversity. Mutations of troponin subunits cause myopathies. Owing to their physiological and pathological importance, troponin variants can be used as specific markers to define muscle quality. In this focused review, we will explore the use of troponin variants as markers for the fiber contents, developmental and differentiation states, contractile functions, and physiological or pathophysiological adaptations of skeletal muscle. As protein structure defines function, profile of troponin variants illustrates how changes at the myofilament level confer functional qualities at the fiber level. Moreover, understanding of the role of troponin modifications and mutants in determining muscle contractility in age-related decline of muscle function and in myopathies informs an approach to improve human health.

scholarly journals THE ULTRASTRUCTURE OF FROG VENTRICULAR CARDIAC MUSCLE AND ITS RELATIONSHIP TO MECHANISMS OF EXCITATION-CONTRACTION COUPLING

1968 ◽  
Vol 38 (1) ◽  
pp. 99-114 ◽  
Author(s):  
Nancy A. Staley ◽  
Ellis S. Benson
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Muscle ◽  
Striated Muscle ◽  
Structural Features ◽  
Mammalian Skeletal Muscle ◽  
Striated Muscles ◽  
Thin Filaments ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Dense Granules

Frog ventricular cardiac muscle has structural features which set it apart from frog and mammalian skeletal muscle and mammalian cardiac muscle. In describing these differences, our attention focused chiefly on the distribution of cellular membranes. Abundant inter cellular clefts, the absence of tranverse tubules, and the paucity of sarcotubules, together with exceedingly small cell diameters (less than 5 µ), support the suggestion that the mechanism of excitation-contraction coupling differs in these muscle cells from that now thought to be characteristic of striated muscle such as skeletal muscle and mammalian cardiac muscle. These structural dissimilarities also imply that the mechanism of relaxation in frog ventricular muscle differs from that considered typical of other striated muscles. Additional ultrastructural features of frog ventricular heart muscle include spherical electron-opaque bodies on thin filaments, inconstantly present, forming a rank across the I band about 150 mµ from the Z line, and membrane-bounded dense granules resembling neurosecretory granules. The functional significance of these features is not yet clear.

scholarly journals Association analysis of TNNI1/XbaI polimorphism on carcass quality in hybrid pigs

2015 ◽  
pp. 59-62
Author(s):  
Andrea Nyilasovits ◽  
János Posta ◽  
Levente Czeglédi ◽  
László Babinszky
Keyword(s):  
Troponin I ◽  
Striated Muscle ◽  
Meat Production ◽  
Thin Filaments ◽  
Potential Marker ◽  
Pcr Rflp ◽  
Troponin Complex ◽  
Myosin Interaction ◽  
Polymerase Chain ◽  
Regulation Of Muscle Contraction

The contractile protein, which is encoded by troponin I 1 (TNNI1) gene, is located on the thin filaments of slow fibres in striated muscle. TNNI1 protein is a part of the troponin complex which plays an important role in regulation of muscle contraction by preventing actin-myosin interaction in absence of calcium. According to biological role, this gene can be potential marker for meat production related traits. The aim of this study is to define whether the previously reported gene polymorphism (EU743939:g.5174T>C) is connected with the slaughter traits measured in a standard slaughterhouse of the examined four-line European hybrid. The study included data from 404 gilts and barrows from 2 different samples. The polymorphism was detected using PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) method with XbaI restriction enzyme. In this study the allele frequencies were found as follows: C: 0.84 and 0.808; T: 0.16 and 0.192. Based on result of the present study no significant impact of polymorphisms on production parameters was found.

Abstract 366: Engineered Human Cardiac Tissue from Skeletal Muscle Derived Cells and Induced Pluripotent Stem Cell Derived Cardiomyocytes

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Kimimasa Tobita ◽  
Jason S Tchao ◽  
Jong Kim ◽  
Bo Lin ◽  
Johnny Huard ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Stem Cell ◽  
Pluripotent Stem Cell ◽  
Cardiac Tissue ◽  
Troponin I ◽  
Troponin T ◽  
Induced Pluripotent Stem Cell ◽  
Human Cardiac Tissue ◽  
Induced Pluripotent ◽  
Immature Myocardium

We have previously shown that rat skeletal muscle derived stem cells differentiate into an immature cardiomyocyte (CM) phenotype within a 3-dimensional collagen gel engineered cardiac tissue (ECT). Here, we investigated whether human skeletal muscle derived progenitor cells (skMDCs) can differentiate into a CM phenotype within ECT similar to rat skeletal muscle stem cells and compared the human skMDC-ECT properties with ECT from human induced pluripotent stem cell (iPSc) derived CMs. SkMDCs differentiated into a cardiac muscle phenotype within ECT and exhibited spontaneous beating activity as early as culture day 4 and maintained their activity for more than 2 weeks. SkMDC-ECTs stained positive for cardiac specific troponin-T and troponin-I, and were co-localized with fast skeletal muscle myosin heavy chain (sk-fMHC) with a striated muscle pattern similar to fetal myocardium. The iPS-CM-ECTs maintained spontaneous beating activity for more than 2 weeks from ECT construction. iPS-CM stained positive for both cardiac troponin-T and troponin-I, and were also co-localized with sk-fMHC while the striated expression pattern of sk-fMHC was lost similar to post-natal immature myocardium. Connexin-43 protein was expressed in both engineered tissue types, and the expression pattern was similar to immature myocardium. The skMDC-ECT significantly upregulated expression of cardiac-specific genes compared to conventional 2D culture. SkMDC-ECT displayed cardiac muscle like intracellular calcium ion transients. The contractile force measurements demonstrated functional properties of fetal type myocardium in both ECTs. Our results suggest that engineered human cardiac tissue from skeletal muscle progenitor cells mimics developing fetal myocardium while the engineered cardiac tissue from inducible pluripotent stem cell-derived cardiomyocytes mimics post-natal immature myocardium.

Calcium-induced movement of troponin-I relative to actin in skeletal muscle thin filaments

Science ◽  
1990 ◽  
Vol 247 (4948) ◽  
pp. 1339-1341 ◽  
Author(s):  
T Tao ◽  
B. Gong ◽  
P. Leavis
Keyword(s):  
Skeletal Muscle ◽  
Troponin I ◽  
Thin Filaments

scholarly journals A distinct cardiopharyngeal mesoderm genetic hierarchy establishes antero-posterior patterning of esophagus striated muscle

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Glenda Comai ◽  
Eglantine Heude ◽  
Sebastian Mella ◽  
Sylvain Paisant ◽  
Francesca Pala ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Striated Muscle ◽  
Striated Muscles ◽  
Food Ingestion ◽  
Loss Of Function ◽  
Pharmacological Studies ◽  
Posterior Migration ◽  
Functional Relevance ◽  
Genetic Signatures ◽  
Genetic Hierarchy

In most vertebrates, the upper digestive tract is composed of muscularized jaws linked to the esophagus that permits food ingestion and swallowing. Masticatory and esophagus striated muscles (ESM) share a common cardiopharyngeal mesoderm (CPM) origin, however ESM are unusual among striated muscles as they are established in the absence of a primary skeletal muscle scaffold. Using mouse chimeras, we show that the transcription factors Tbx1 and Isl1 are required cell-autonomously for myogenic specification of ESM progenitors. Further, genetic loss-of-function and pharmacological studies point to MET/HGF signaling for antero-posterior migration of esophagus muscle progenitors, where Hgf ligand is expressed in adjacent smooth muscle cells. These observations highlight the functional relevance of a smooth and striated muscle progenitor dialogue for ESM patterning. Our findings establish a Tbx1-Isl1-Met genetic hierarchy that uniquely regulates esophagus myogenesis and identify distinct genetic signatures that can be used as framework to interpret pathologies arising within CPM derivatives.

P4420Is exercise-induced cardiac troponin release caused by skeletal muscle injury?

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
T Paana ◽  
S Jaakkola ◽  
E Tuunainen ◽  
S Wittfooth ◽  
K Bamberg ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Troponin ◽  
Muscle Injury ◽  
Troponin I ◽  
Troponin T ◽  
Skeletal Muscle Injury ◽  
Coronary Syndrome ◽  
Marathon Race ◽  
Recreational Runners ◽  
Exercise Induced

Abstract Background Cardiac troponins (cTn) are highly sensitive and specific markers for cardiac injury and a key element in the diagnosis of acute coronary syndrome. Strenuous exercise is known to induce increases in cTn, but the causative factors remain ambiguous. It is also equivocal whether exercise induced skeletal muscle injury is associated with cTn elevation. Purpose The aim of this study was to identify independent predictors for the rise in cardiac troponin T (cTnT) and I (cTnI) concentration and to focus on the relationship between skeletal muscle injury measured by skeletal troponin I (skTnI) and cTn elevations after a marathon race in a large group of male recreational runners. Methods A total of 40 recreational runners participating in the marathon in our city were recruited. The study included baseline visit (prerace) and immediate post-race sampling. Results The post-marathon cTnT concentration rose above the reference limit in 38 (95%) participants and the detection limit for cTnI was exceeded in 34 (85%) participants. Similarly, a 10-fold increase in skTnI concentration was observed and elevated post-race values were seen in all participants. There was no significant correlation between the post-race cTnT or cTnT change and post-race skTnI (Spearman's rho = 0.249, p=0.122, rho = 0.285, p=0.074). However, post-race cTnI and change in cTnI were associated with post-race skTnI (rho = 0.404, p=0.01, rho = 0.460, p=0.003) and creatine kinase (r=0.368, p=0.019) concentration. Subjective exertion or self-reported muscle symptoms did not correlate with post-race cTnT, cTnI or skTnI levels. Post-Race cTnT <40 Post-Race cTnT ≥40 p-value n=18 n=22 Age, years 53.3±12.2 44.0±11.9 0.002 Active training, years 12.0 (9.3) 17.0 (15.8) 0.190 Muscle symptoms 7 (38.9) 11 (52.4) 0.523 Creatinine kinase, ug/l 406 (137) 399 (319) 0.163 N-terminal proBNP ng/l 137±168 158±277 0.783 Skeletal Troponin I, ng/ml 28.6 (41) 56.7 (143) 0.199 Figure 1 Conclusions Cardiac troponin became abnormal in almost all runners after marathon race. The exercise-induced rise in cardiac troponin I is related to simultaneous release of skeletal troponin I. The mechanism of this association remains uncertain, but clinicians should be cautious when interpreting post-exercise troponin levels without clinical symptoms and signs of myocardial ischemia.

Functional and evolutionary relationships of troponin C

2007 ◽  
Vol 32 (1) ◽  
pp. 16-27 ◽  
Author(s):  
Todd E. Gillis ◽  
Christian R. Marshall ◽  
Glen F. Tibbits
Keyword(s):  
Functional Properties ◽  
Thin Filament ◽  
Troponin I ◽  
Striated Muscle ◽  
Troponin T ◽  
Extensive Study ◽  
Troponin C ◽  
High Conservation ◽  
Cross Bridges ◽  
And Function

Striated muscle contraction is initiated when, following membrane depolarization, Ca2+ binds to the low-affinity Ca2+ binding sites of troponin C (TnC). The Ca2+ activation of this protein results in a rearrangement of the components (troponin I, troponin T, and tropomyosin) of the thin filament, resulting in increased interaction between actin and myosin and the formation of cross bridges. The functional properties of this protein are therefore critical in determining the active properties of striated muscle. To date there are 61 known TnCs that have been cloned from 41 vertebrate and invertebrate species. In vertebrate species there are also distinct fast skeletal muscle and cardiac TnC proteins. While there is relatively high conservation of the amino acid sequence of TnC homologs between species and tissue types, there is wide variation in the functional properties of these proteins. To date there has been extensive study of the structure and function of this protein and how differences in these translate into the functional properties of muscles. The purpose of this work is to integrate these studies of TnC with phylogenetic analysis to investigate how changes in the sequence and function of this protein, integrate with the evolution of striated muscle.

scholarly journals Conformational modulation of slow skeletal muscle troponin T by an NH2-terminal metal-binding extension

2000 ◽  
Vol 279 (4) ◽  
pp. C1067-C1077 ◽  
Author(s):  
Jian-Ping Jin ◽  
Aihua Chen ◽  
Ozgur Ogut ◽  
Qi-Quan Huang
Keyword(s):  
Skeletal Muscle ◽  
Monoclonal Antibody ◽  
Metal Binding ◽  
Metal Ion ◽  
Troponin I ◽  
Troponin T ◽  
Terminal Region ◽  
Sequence Motif ◽  
Fast Skeletal Muscle ◽  
Slow Skeletal Muscle

Troponin T (TnT) is an essential element in the thin filament Ca2+-regulatory system controlling striated muscle contraction. Alternative RNA splicing generates developmental and muscle type-specific TnT isoforms differing in the hypervariable NH2-terminal region. Using avian fast skeletal muscle TnT containing a metal-binding segment, we have demonstrated a role of the NH2-terminal domain in modulating the conformation of TnT (Wang J and Jin JP. Biochemistry 37: 14519–14528, 1998). To further investigate the structure-function relationship of TnT, the present study constructed and characterized a recombinant protein in which the metal-binding peptide present in avian fast skeletal muscle TnT was fused to the NH2 terminus of mouse slow skeletal muscle TnT. Metal ion or monoclonal antibody binding to the NH2-terminal extension induced conformational changes in other domains of the model TnT molecule. This was shown by the altered affinity to a monoclonal antibody against the COOH-terminal region and a polyclonal antiserum recognizing multiple epitopes. Protein binding assays showed that metal binding to the NH2-terminal extension had effects on the interaction of TnT with troponin I, troponin C, and most significantly, tropomyosin. The data indicate that the NH2-terminal Tx [4–7 repeats of a sequence motif His-(Glu/Ala)-Glu-Ala-His] extension confers a specific conformational modulation in the slow skeletal muscle TnT.

Cardiac Troponin I and T Concentrations in Patients with Cocaine-Associated Chest Pain

1996 ◽  
Vol 33 (3) ◽  
pp. 183-186 ◽  
Author(s):  
Mary McLaurin ◽  
Fred S Apple ◽  
Timothy D Henry ◽  
Scott W Sharkey
Keyword(s):  
Skeletal Muscle ◽  
Chest Pain ◽  
Cardiac Troponin ◽  
Muscle Injury ◽  
Troponin I ◽  
Troponin T ◽  
Acute Chest Pain ◽  
Cardiac Troponin I ◽  
Skeletal Muscle Injury ◽  
Rule Out

Patients with cocaine-related chest pain with electrocardiographic (ECG) abnormalities are often admitted to rule out acute myocardial infarction (AMI). Cardiac troponin I and T should be superior to measurement of creatine kinase (CK)—MB for detecting cardiac injury in patients with coexisting skeletal muscle injury. We prospectively evaluated 19 consecutive patients with acute chest pain related to cocaine use who were hospitalized to rule out AMI. The admission ECG was abnormal in 16 of 19 patients. Total CK and CK—MB were elevated during the hospital course in 14 and 3 patients, respectively. Cardiac troponin I and cardiac troponin T levels were within normal limits in all patients demonstrating that recent myocardial injury did not occur. Clinically, no patient had an AMI. Cocaine-induced thoracic skeletal muscle injury or transient cocaine-induced coronary vasospasm should be considered as alternative sources of chest pain in these patients.

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