In vivo and in vitro observations on laminin production by Schwann cells.

Abstract

Recent reports on the dystrophic mouse mutant suggest that the prominent extracellular matrix component of peripheral nerve tissues plays an important role in peripheral nerve development. We have examined the disposition of two prominent extracellular matrix components, fibronectin and laminin, both in mature peripheral nerve in vivo and in an in vitro system that allows study of Schwann cells in various functional states. In frozen sections of whole nerve, staining with antibodies to fibronectin and laminin shows that fibronectin stains throughout the endoneurium while laminin staining is restricted to regions known to contain basal lamina, particularly the basal lamina of each ensheathing Schwann cell. Tissue culture studies indicate that fibronectin staining at the light microscopic level is a reliable marker for fibroblasts (and not Schwann cells) in culture; conversely, antibodies to laminin stain components related to the Schwann cell surface but not components related to fibroblasts. Unexpectedly, Schwann cells in culture produce laminin at all stages in development, whether in contact with axons or not. As Schwann cells in culture begin to ensheathe axons, punctate regions of laminin on their surfaces become confluent. After ensheathment is completed, a continuous line of staining is found in the region of the Schwann cell basal lamina. It has been established that Schwann cells produce a basal lamina only when in contact with axons. Therefore, the production of laminin appears to be necessary but not sufficient for basal lamina formation. (5) and fibronectin (6, 7).We have now studied the appearance of fibronectin and the basal lamina component laminin, both in vivo and during development of peripheral nerve constituents in vitro. The role of the ECM in peripheral nerve development is poorly understood; studies on the dystrophic mouse mutant (8-10) and observations on Schwann cell/neuron cultures grown in defined medium (11) have demonstrated a correlation between abnormal ECM development and aberrant Schwann cell-axonal relationships. We report here immunohistochemical evidence that (i) both fibronectin and laminin are components of the mature peripheral nerve but they are localized in two distinct patterns; (ii) in tissue culture preparations, antibodies to each protein differentially recognize Schwann cells (laminin) and fibroblasts (fibronectin); and (iii) laminin, a known component of the ECM, is expressed by the Schwann cell prior to the development of a morphologically recognizable basal lamina. A preliminary report of this work has appeared (12

Neuropathology for the Neuroradiologist: Antoni A and Antoni B Tissue Patterns

“…18,19 Miettinen et al 20 investigated benign and malignant soft tissue tumors immunohistologically for the presence of laminin. The results showed intense laminin positivity in schwannomas and neurofibromas and less intense positivity in leiomyomas and leiomyosarcomas, whereas fibrous histiocytomas and fibrosarcomas generally were negative.…”

Adherence of Mycobacterium leprae to Schwann cells in vitro

“…1985;revised version accepted 25 Oct. 1985. * Correspondence and requests for offprints should be sent to Dr N. H. Antia monolayer cultures of 95% pure Schwann cells were obtained within 4 days. The purity of the Schwann cells in cultures was determined by positive staining for nonspecific esterase by the a-naphthyl acetate method (Bancroft, 1975) and by an indirect immunofluorescence test with anti-laminin antibody (Cornbrooks et al, 1983).…”

Laminin expression in the mouse lung increases with development and stimulates spontaneous organotypic rearrangement of mixed lung cells

“…As originally extracted from the mouse Engelbreth Holm Swam (EHS) tumor and from placental tissue, this molecule is composed of three polypeptide chains referred to as A (M, = 400,000), B1 (M, = 222,000), and B2 (M, = 210,000) linked by disulfide bonds (Timpl et al, 1979). Several molecular isoforms of laminin have been identified, including a variant form lacking the A chain (Cornbrooks et al, 1983;Mohan and Spiro, 1986;Aratani and Kitagawa, 1988). As with many large extracellular matrix molecules, laminin has a variety of biological effects on cells, including stimulation of adhesion, migration, growth and differentiation (Martin and Timpl, 1987;Kleinman et al, 1987a).…”