Assembly of Myotendinous Junctions in the Chick Embryo: Deposition of P68 Is an Early Event in Myotendinous Junction Formation

1994 ◽  
Vol 163 (2) ◽  
pp. 447-456 ◽  
Author(s):  
James G. Tidball
Keyword(s):  
Chick Embryo ◽  
Early Event ◽  
Myotendinous Junction ◽  
Junction Formation ◽  
Myotendinous Junctions

scholarly journals Fibroblast fusion to the muscle fiber regulates myotendinous junction formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wesal Yaseen ◽  
Ortal Kraft-Sheleg ◽  
Shelly Zaffryar-Eilot ◽  
Shay Melamed ◽  
Chengyi Sun ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Musculoskeletal System ◽  
Smooth Transition ◽  
Common Mechanism ◽  
Myotendinous Junction ◽  
Body Movements ◽  
Dual Identity ◽  
Junction Formation ◽  
Myogenic Program ◽  
Developing Muscle

AbstractVertebrate muscles and tendons are derived from distinct embryonic origins yet they must interact in order to facilitate muscle contraction and body movements. How robust muscle tendon junctions (MTJs) form to be able to withstand contraction forces is still not understood. Using techniques at a single cell resolution we reexamine the classical view of distinct identities for the tissues composing the musculoskeletal system. We identify fibroblasts that have switched on a myogenic program and demonstrate these dual identity cells fuse into the developing muscle fibers along the MTJs facilitating the introduction of fibroblast-specific transcripts into the elongating myofibers. We suggest this mechanism resulting in a hybrid muscle fiber, primarily along the fiber tips, enables a smooth transition from muscle fiber characteristics towards tendon features essential for forming robust MTJs. We propose that dual characteristics of junctional cells could be a common mechanism for generating stable interactions between tissues throughout the musculoskeletal system.

Adhesive strength of single muscle cells to basement membrane at myotendinous junctions

1989 ◽  
Vol 67 (3) ◽  
pp. 1063-1069 ◽  
Author(s):  
J. G. Tidball ◽  
M. Chan
Keyword(s):  
Basement Membrane ◽  
Muscle Cells ◽  
Isometric Tension ◽  
Breaking Stress ◽  
Myotendinous Junction ◽  
Compression Injury ◽  
Cross Sectional ◽  
Biologically Relevant ◽  
Strain And Strain Rate ◽  
Myotendinous Junctions

Whole muscles loaded to failure frequently fail at or near myotendinous junctions. The present investigation was directed toward determining the breaking stress and failure site of intact and injured myotendinous junction preparations consisting of muscle cells dissected free from surrounding parallel structures but still attached to tendon collagen fibers. These tests show that the breaking stress for intact myotendinous units is 2.7 x 10(5) N/m2, expressed relative to cell cross-sectional area. Failure occurs immediately external to the junction membrane between the cell membrane and lamina densa of the basement membrane. Site and stress at failure are independent of strain and strain rate over a biologically relevant range. Breaking stress in the plane of the membrane, corrected for membrane folding, is 1.2 X 10(4) N/m2. This value is not significantly greater than stress at maximum isometric tension for these cells at these sarcomere lengths. After compression injury, cells fail within the compression site at significantly lower stress (1.9 X 10(5) N/m2). These findings suggest that, in muscle strain injuries that occur under conditions simulated here, failure occurs at myotendinous junctions unless the muscle has suffered previous compression injury leading to failure within the muscle.

scholarly journals Fibroblast fusion to the muscle fiber regulates myotendinous junction formation

2020 ◽  
Author(s):  
Wesal Yaseen-Badarneh ◽  
Ortal Kraft-Sheleg ◽  
Shelly Zaffryar-Eilot ◽  
Shay Melamed ◽  
Chengyi Sun ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Musculoskeletal System ◽  
Smooth Transition ◽  
Common Mechanism ◽  
Myotendinous Junction ◽  
Body Movements ◽  
Dual Identity ◽  
Junction Formation ◽  
Myogenic Program ◽  
Developing Muscle

SummaryVertebrate muscles and tendons are derived from distinct embryonic origins yet they must interact in order to facilitate muscle contraction and body movements. How robust muscle tendon junctions (MTJs) form to be able to withstand contraction forces is still not understood. Using techniques at a single cell resolution we reexamined the classical view of distinct identities for the tissues composing the musculoskeletal system. We identified fibroblasts that have switched on a myogenic program and demonstrate these dual identity cells fuse into the developing muscle fibers along the MTJs facilitating the introduction of fibroblast-specific transcripts into the elongating myofibers. We suggest this mechanism resulting in a hybrid muscle fiber, primarily along the fiber tips, enables a smooth transition from muscle fiber characteristics towards tendon features essential for forming robust MTJs. We propose that dual characteristics of junctional cells could be a common mechanism for generating stable interactions between tissues throughout the musculoskeletal system.

Talin, vinculin and DRP (utrophin) concentrations are increased at mdx myotendinous junctions following onset of necrosis

1994 ◽  
Vol 107 (6) ◽  
pp. 1477-1483 ◽  
Author(s):  
D.J. Law ◽  
D.L. Allen ◽  
J.G. Tidball
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Cytoskeletal Proteins ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Myotendinous Junction ◽  
Glycoprotein Complex ◽  
Transmembrane Glycoprotein ◽  
Muscle Necrosis ◽  
Myotendinous Junctions

Duchenne muscular dystrophy (DMD) and the myopathy seen in the mdx mouse both result from absence of the protein dystrophin. Structural similarities between dystrophin and other cytoskeletal proteins, its enrichment at myotendinous junctions, and its indirect association with laminin mediated by a transmembrane glycoprotein complex suggest that one of dystrophin's functions in normal muscle is to form one of the links between the actin cytoskeleton and the extracellular matrix. Unlike Duchenne muscular dystrophy patients, mdx mice suffer only transient muscle necrosis, and are able to regenerate damaged muscle tissue. The present study tests the hypothesis that mdx mice partially compensate for dystrophin's absence by upregulating one or more dystrophin-independent mechanisms of cytoskeleton-membrane association. Quantitative analysis of immunoblots of adult mdx muscle samples showed an increase of approximately 200% for vinculin and talin, cytoskeletal proteins that mediate thin filament-membrane interactions at myotendinous junctions. Blots also showed an increase (143%) in the dystrophin-related protein called utrophin, another myotendinous junction constituent, which may be able to substitute for dystrophin directly. Muscle samples from 2-week-old animals, a period immediately preceding the onset of muscle necrosis, showed no significant differences in protein concentration between mdx and controls. Quantitative analyses of confocal images of myotendinous junctions from mdx and control muscles show significantly higher concentrations of talin and vinculin at the myotendinous junctions of mdx muscle. These findings indicate that mdx mice may compensate in part for the absence of dystrophin by increased expression of other molecules that subsume dystrophin's mechanical function.

scholarly journals Zasp is required for the assembly of functional integrin adhesion sites

2007 ◽  
Vol 179 (7) ◽  
pp. 1583-1597 ◽  
Author(s):  
Klodiana Jani ◽  
Frieder Schöck
Keyword(s):  
Focal Adhesions ◽  
Myotendinous Junction ◽  
Lim Domain ◽  
Transmembrane Receptors ◽  
Cell Matrix ◽  
Adhesion Sites ◽  
Alternatively Spliced ◽  
Dependent Cell ◽  
Cell Matrix Adhesion ◽  
Myotendinous Junctions

The integrin family of heterodimeric transmembrane receptors mediates cell–matrix adhesion. Integrins often localize in highly organized structures, such as focal adhesions in tissue culture and myotendinous junctions in muscles. Our RNA interference screen for genes that prevent integrin-dependent cell spreading identifies Z band alternatively spliced PDZ-motif protein (zasp), encoding the only known Drosophila melanogaster Alp/Enigma PDZ-LIM domain protein. Zasp localizes to integrin adhesion sites and its depletion disrupts integrin adhesion sites. In tissues, Zasp colocalizes with βPS integrin in myotendinous junctions and with α-actinin in muscle Z lines. Zasp also physically interacts with α-actinin. Fly larvae lacking Zasp do not form Z lines and fail to recruit α-actinin to the Z line. At the myotendinous junction, muscles detach in zasp mutants with the onset of contractility. Finally, Zasp interacts genetically with integrins, showing that it regulates integrin function. Our observations point to an important function for Zasp in the assembly of integrin adhesion sites both in cell culture and in tissues.

scholarly journals Tissue Engineering for the Insertions of Tendons and Ligaments: An Overview of Electrospun Biomaterials and Structures

2021 ◽  
Vol 9 ◽  
Author(s):  
Alberto Sensini ◽  
Gabriele Massafra ◽  
Carlo Gotti ◽  
Andrea Zucchelli ◽  
Luca Cristofolini
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Myotendinous Junction ◽  
Stress Concentrations ◽  
Comprehensive Overview ◽  
Electrospinning Technique ◽  
Junction Site ◽  
Wide Range ◽  
Myotendinous Junctions

The musculoskeletal system is composed by hard and soft tissue. These tissues are characterized by a wide range of mechanical properties that cause a progressive transition from one to the other. These material gradients are mandatory to reduce stress concentrations at the junction site. Nature has answered to this topic developing optimized interfaces, which enable a physiological transmission of load in a wide area over the junction. The interfaces connecting tendons and ligaments to bones are called entheses, while the ones between tendons and muscles are named myotendinous junctions. Several injuries can affect muscles, bones, tendons, or ligaments, and they often occur at the junction sites. For this reason, the main aim of the innovative field of the interfacial tissue engineering is to produce scaffolds with biomaterial gradients and mechanical properties to guide the cell growth and differentiation. Among the several strategies explored to mimic these tissues, the electrospinning technique is one of the most promising, allowing to generate polymeric nanofibers similar to the musculoskeletal extracellular matrix. Thanks to its extreme versatility, electrospinning has allowed the production of sophisticated scaffolds suitable for the regeneration of both the entheses and the myotendinous junctions. The aim of this review is to analyze the most relevant studies that applied electrospinning to produce scaffolds for the regeneration of the enthesis and the myotendinous junction, giving a comprehensive overview on the progress made in the field, in particular focusing on the electrospinning strategies to produce these scaffolds and their mechanical, in vitro, and in vivo outcomes.

scholarly journals Stable Gastric Pentadecapeptide BPC 157 as a Therapy for the Disable Myotendinous Junctions in Rats

Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1547
Author(s):  
Mladen Japjec ◽  
Katarina Horvat Pavlov ◽  
Andreja Petrovic ◽  
Mario Staresinic ◽  
Bozidar Sebecic ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Quadriceps Tendon ◽  
Quadriceps Muscle ◽  
Myotendinous Junction ◽  
Mrna Levels ◽  
Bpc 157 ◽  
The Disabled ◽  
Pentadecapeptide Bpc 157 ◽  
Cox 2 ◽  
Myotendinous Junctions

(1) Aim: The stable gastric pentadecapeptide BPC 157 is known to heal transected muscle, tendon, and ligament. Thereby, in this study, we investigated the effect of BPC 157 on the dissection of the quadriceps tendon from the quadriceps muscle in rats. (2) Materials and Methods: Myotendinous junction defect, which cannot heal spontaneously in rats, as evidenced with consistent macro/microscopic, biomechanical, functional assessments, eNOS, and COX-2 mRNA levels and oxidative stress and NO-levels in the myotendinous junctions. BPC 157 (10 µg/kg, 10 ng/kg) regimen was given (i) intraperitoneally, first application immediately after surgery, last 24 h before sacrifice; (ii) per-orally, in drinking water (0.16 µg/mL, 0.16 ng/mL, 12 mL/rat/day), till the sacrifice at 7, 14, 28 and 42 postoperative days. (3) Results: These BPC 157 regimens document prominent therapy effects (macro/microscopic, biomechanical, functional much like eNOS and COX-2 mRNA levels and counteracted oxidative stress and NO-levels in the myotendinous junctions), while controls have a poor presentation. Especially, in rats with the disabled myotendinous junction, along with full functional recovery, BPC 157 counteracts muscle atrophy that is regularly progressive and brings muscle presentation close to normal. Accordingly, unlike the perilous course in controls, those rats, when receiving BPC 157 therapy, exhibit a smaller defect, and finally defects completely disappear. Microscopically, there are no more inflammatory infiltrate, well-oriented recovered tissue of musculotendon junction appears in BPC 157 treated rats at the 28 days and 42 days. (4) Conclusions: BPC 157 restores myotendinous junction in accordance with the healing of the transected muscle, tendon, and ligament.

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