Ultrastructural and Immunochemical Evidence of Actin in the Tendon Cells

Ippolito, Ernesto; Pg, Natali; Postacchini, Franco; Accinni, L.; C, De Martino

doi:10.1097/00003086-197707000-00054

Cited by 19 publications

(22 citation statements)

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“…In vertebrates, tendons are morphologically diverse tissues and their strength depend mainly on extracellular collagen fibrils (Kannus, 2000;Banos et al, 2008), however, well developed actin and myosin bundles are also observed in cytoplasm and around the nucleus in rabbit tendon cells (Ippolito et al, 1977;Postacchini et al, 1978). In Drosophila, the spectraplakin family protein Shot has a major role in formation and maintenance of cytoskeletal organization in tendon cells (Subramanian et al, 2003;Alves-Silva et al, 2008), but the mammalian spectraplakins, Bpag1/dystonin and MACF1, which are Shot orthologs, have not yet been analyzed in tendon cells.…”

Section: Tablementioning

confidence: 99%

Loss of Drosophila A-type lamin C initially causes tendon abnormality including disintegration of cytoskeleton and nuclear lamina in muscular defects

Uchino

Nonaka

Horigome

et al. 2013

Developmental Biology

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a b s t r a c tLamins are the major components of nuclear envelope architecture, being required for both the structural and informational roles of the nuclei. Mutations of lamins cause a spectrum of diseases in humans, including muscular dystrophy. We report here that the loss of the A-type lamin gene, lamin C in Drosophila resulted in pupal metamorphic lethality caused by tendon defects, matching the characteristics of human A-type lamin revealed by Emery-Dreifuss muscular dystrophy (EDMD). In tendon cells lacking lamin C activity, overall cell morphology was affected and organization of the spectraplakin family cytoskeletal protein Shortstop which is prominently expressed in tendon cells gradually disintegrated, notably around the nucleus and in a manner correlating well with the degradation of musculature. Furthermore, lamin C null mutants were efficiently rescued by restoring lamin C expression to shortstop-expressing cells, which include tendon cells but exclude skeletal muscle cells. Thus the critical function of A-type lamin C proteins in Drosophila musculature is to maintain proper function and morphology of tendon cells.

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Section: Tablementioning

confidence: 99%

Loss of Drosophila A-type lamin C initially causes tendon abnormality including disintegration of cytoskeleton and nuclear lamina in muscular defects

Uchino

Nonaka

Horigome

et al. 2013

Developmental Biology

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“…The actin isoform a-smooth muscle actin has been identified in fibroblastic cells of normal tendons and ligaments [20,21,25]. a-smooth muscle actin is expressed by smooth muscle cells [31,35], pericytes 1341, and highly differentiated fibroblastic cells, the so-called myofibroblasts [12,29,3 1-33,361.…”

Section: Introductionmentioning

confidence: 99%

α‐Smooth muscle actin is expressed by fibroblastic cells of the ovine anterior cruciate ligament and its free tendon graft during remodeling

Weiler

Unterhauser

Bail

et al. 2002

Journal Orthopaedic Research

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Contractile fibroblastic cells expressing the a-smooth muscle actin isoform, so-called myofibroblasts, have been identified to play a possible role during the healing of the medial collateral ligament by means of restoring the tissues in situ strain via extracellular matrix contraction. Recently, these cells have also been identified to be a normal part of the human anterior cruciate ligament. It has been hypothesized that myofibroblasts play a role in the wrinkling of the extracellular matrix. The goal of the present study was to identify myofibroblasts in the intact ovine anterior cruciate ligament and a free autologous tendon graft during remodeling after anterior cruciate ligament reconstruction. In 36 mature merino sheep the anterior cruciate ligament was replaced with an ipsilateral Achilles tendon split graft. Midsubstance tissue samples were immunostained for a-smooth muscle actin at 6,9, 12,24, 52, and 104 weeks. Myofibroblasts were identified in the intact ovine anterior cruciate ligament as well as in the Achilles tendon graft prior to implantation. During remodeling the first myofibroblasts were found at six weeks within newly formed fiber bundles. At 24, 52, and 104 weeks myofibroblast distribution and cell density were similar to those of the intact ovine anterior cruciate ligament. These findings indicate that a-smooth muscle actin containing fibroblastic cells are a regular part of the intact as well as the remodeled anterior cruciate ligament. There is evidence that myofibroblasts may be involved in maintaining tissue homeostasis in the mature ligament e.g., by means of crimp formation. The presence of these cells during the early remodeling may further indicate that asmooth muscle actin containing fibroblastic cells are involved in the earliest stages of fiber bundle formation. The role and function of this special cell type for the anterior cruciate ligament needs to be further clarified.

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“…Fascicles are predominantly aligned along the longitudinal axis of the tendon, being responsible for its tensile strength. In addition to collagen, a variety of glycosaminoglycans, proteoglycans (large and small), glycoproteins and other non collagenous proteins, in particular tenascin-C, are secreted by tenocytes and orderly inserted into the collagen fascicle network [8][9][10][11]. Tenascin-C is a molecule containing a number of repeating fibronectin type-III domains which undergo stressinduced unfolding thus allowing the whole macromolecule to behave as an elastic protein.…”

Section: Tendons Biochemical Composition and Ultrastructurementioning

confidence: 99%

Role of Metalloproteinases in Tendon Pathophysiology

Sbardella¹,

Tundo²,

Fasciglione³

et al. 2014

MRMC

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Abstract:Tendons play a crucial role in musculoskeletal functioning because they physically connect bones and muscles making the movement of articular joints possible. The molecular composition of tendons mostly include collagen I fibrils, which aggregate together to form fibers to form a fascicle. A complex network composed of resident cells (i.e., tenocytes) and extracellular matrix macromolecules (glycosaminoglycans, proteoglycans, glycoproteins and other non collagenous proteins) interact and define the structure of tendons and their properties. Development, renewal and remodeling of tendons composition occur at all ages of living organisms so the homeostasis of proteolytic systems is a critical issue. A major role is played by Metalloproteinases, a family of Zn 2+ -dependent endopeptidases involved in the catabolism of several components of the extracellular matrix, such as collagens, proteoglycans, fibronectin and many others. Among these, two main classes are mostly involved in tendon pathophysiology, namely the Matrix Metalloproteinases (MMPs) and a Disintegrin-like and Metalloproteinase domain with Thrombospondin motifs (ADAMTSs). This study analyses the various aspects of the roles played by Metalloproteinases in the physiological and pathological processes of tendons.

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Ultrastructural and Immunochemical Evidence of Actin in the Tendon Cells

Cited by 19 publications

References 0 publications

Loss of Drosophila A-type lamin C initially causes tendon abnormality including disintegration of cytoskeleton and nuclear lamina in muscular defects

Loss of Drosophila A-type lamin C initially causes tendon abnormality including disintegration of cytoskeleton and nuclear lamina in muscular defects

α‐Smooth muscle actin is expressed by fibroblastic cells of the ovine anterior cruciate ligament and its free tendon graft during remodeling

Role of Metalloproteinases in Tendon Pathophysiology

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