Astrocytes in culture express fibrillar collagen

Abstract

The use of monoclonal antibodies has led to much progress in the characterization of extracellular matrix components of the CNS. F1C3 is a monoclonal antibody raised against the astrocytic cell line, Neu7. Analysis by immunoprecipitation and Western blots of the F1C3 antigen in Neu7 cell lysates and conditioned medium reveals a recognition of several protein bands around 140 -230 kD. Internal peptide sequence data from these bands indicate that they are highly homologous to fibrillar collagens, and the F1C3 antigen is specifically digested by the collagenase I protease. Other glial cell lines show F1C3 antigen expression including A7, C6, and U373. Cultures of neonatal primary astrocytes also express F1C3 antigen, and Western blot analysis of rat brain extracts from different ages and parts of the brain confirm an in vivo expression of F1C3 protein. The significance of the expression of fibrillar collagenlike proteins by astrocytes is discussed together with its possible implication during developmental processes and in the context of CNS lesions and regeneration. GLIA 41: 382-392, 2003.

Brain-Specific Deletion of Extracellular Signal-Regulated Kinase 2 Mitogen-Activated Protein Kinase Leads to Aberrant Cortical Collagen Deposition

“…Immunofluorescence staining was performed with a monoclonal antibody (F1C3) previously determined to recognize a shared epitope (GPPGPVG) in fibrillar collagens I, II, and V. 34 Compared with wild-type cultures, we observed a striking increase in the fraction of cells positive for F1C3 (Figure 7). Thus, fibrillar collagen production could be under the cell-autonomous negative control of an ERK2-mediated signal.…”

“…30 Recent work indicates that astrocytes in culture can synthesize and secrete fibrillar collagens. 26,34 Some nonfibrillar collagens, including type XVII, are expressed by neurons. 49 In addition, gene profiling studies of fluorescence-activated cell-sorted astrocytes, oligodendroglia, and neurons confirmed differential expression of multiple collagen genes in astrocytes, as well as oligodendroglia and neurons.…”

Collagens in the developing and diseased nervous system

“…Inhibition of fibril formation in the brain could be the consequence of interactions between the astrocytes and the meninges. Indeed, in vitro, astrocytes are able to secrete fibrillar collagen but in vivo their collagen synthesis is suppressed [24]. Two mechanisms are suspected to be involved: first, a secretion by the meninges of an unknown diffusible inhibitory factor and, second, an inhibitory autocrine loop on astrocytes involving Epidermal Growth Factor [25].…”

Astrocytes in the tempest of multiple sclerosis

“…It is supposed to function as a physical and a biological barrier that limits neuroinflammation and the expansion of MS lesions [25]. Importantly, astrocytes might be the cells that produce major collagen components of the fibrosis in MS [25], as they were shown to express these molecules in vitro [26]. As already mentioned, astrocytes induce apoptosis in T cells through generation of an ECM component osteonectin [18].…”