Interferon-beta, an autocrine cytokine, suppresses human fetal skin fibroblast migration into a denuded area in a cell monolayer but is not involved in the age-related decline of cell migration

Interferon-β gene transfer inhibits melanoma cells adhesion and migration

We evaluated the effects of expression of interferon-β (IFNβ) after lipofection on melanoma cells adhesion and migration. Three canine mucosal (Ak, Br and Ol) and one human dermal (SB2) melanomas were assayed. By means of the wound healing assay, we found a significant inhibitory effect of canine IFNβ gene expression on cells migration in Br and Ol monolayers. This effect could be reproduced on unlipofected Ol cells with conditioned culture media obtained from canine IFNβ gene-lipofected Ol cells, and with recombinant human IFNβ on unlipofected SB2 cells. Furthermore, IFNβ gene expression of the four tested tumor cells significantly inhibited their adhesion to extracellular matrix (ECM) proteins and their spreading from multicellular spheroids onto gelatin coating. The addition of catalase reverted the increase of reactive oxygen species (ROS) in Ol cells and the inhibition of cell migration in monolayers (Ol) and spheroids (Ol an SB2) produced by canine and human IFNβ expression, suggesting the involvement of ROS as mediators of IFNβ action on the cells interactions with ECM. Together with its known immune, antiangiogenic and cytotoxic effects, the present data strongly support more studies exploring the clinical potential of IFNβ for cancer therapy.

Interferon-{beta} inhibits bleomycin-induced lung fibrosis by decreasing transforming growth factor-{beta} and thrombospondin

Pulmonary fibrosis is the result of abnormal processes of repair that occur after lung injury. Transforming growth factor (TGF)-beta is a key molecule in the progression of pulmonary fibrosis. Although clinical use of interferon (IFN)-beta did not improve survival in patients with idiopathic pulmonary fibrosis, because some preclinical studies have suggested that IFN-beta is a potent inhibitor of fibrogenesis, beneficial effects of IFN-beta have been expected. We therefore attempted to determine effects of IFN-beta and investigated the mechanism of action of IFN-beta in bleomycin-induced pulmonary fibrosis. Bleomycin at Day 0 and IFN-beta for 4 wk were administered intravenously to ICR mice. At 28 d after bleomycin injection, histologic and chemical analysis was performed for evaluation of effects of IFN-beta. Tissue distribution and amounts of TGF-beta1 and thrombospondin (TSP)-1/2 were analyzed. IFN-beta attenuated prolylhydroxylase activity, resulting in inhibition of pulmonary fibrosis. Bleomycin-induced increase in TGF-beta1 in epithelial cells and extracellular matrix was attenuated by IFN-beta. TSP-1/2 was limited in platelets of control mice, but was present in foamy cells in fibrotic regions induced by bleomycin. These findings suggest that the antifibrotic effect of IFN-beta is inhibition of TGF-beta and its activation via decrease in TSP-1/2 in lung tissue and change in location of TSP-1/2 from platelets to foamy cells.

Impaired migration, integrin function, and actin cytoskeletal organization in dermal fibroblasts from a subset of aged human donors

Deficits in the motility of fibroblasts contribute to age-related impairment of wound healing. We analyzed 'young' fibroblasts from four healthy donors 22-30 years old and 'aged' fibroblasts from six healthy donors 81-92 years old for migratory ability on type I collagen, secretion of matrix metalloproteases (MMPs), attachment to matrices and, expression and function of integrin alpha2beta1. Cells from each donor were analyzed separately in each experiment. Whereas migration of young fibroblasts was uniformly robust, three aged lines migrated well and three migrated poorly. Synthesis of MMP1 and TIMP1, but not MMP2 or MMP9, was increased in the aged fibroblasts relative to the young fibroblast lines irrespective of their motility. All lines of young and aged fibroblasts attached to plastic or collagen with similar efficiency. Although young and aged fibroblasts expressed comparable levels of the alpha2 integrin; the lines of aged fibroblasts that were poor migrators exhibited a significant reduction in alpha2beta1 function relative to fibroblasts with normal migratory capacities. Moreover, the lines of aged fibroblasts that exhibited poor migration demonstrated a disordered actin cytoskeleton and a reduced ability to contract collagen gels. In conclusion, aged fibroblasts, unlike young fibroblasts, displayed variable migratory capacities. Deficient migration by specific lines of aged fibroblasts was not related to the capacity to attach, express alpha2 integrin, or secrete MMPs and TIMP1, but was characterized by disorganized cytoskeletal actin and reduced alpha2beta1 function.

Aging fibroblasts present reduced epidermal growth factor (EGF) responsiveness due to preferential loss of EGF receptors

Wound healing is compromised in aging adults in part due to decreased responsiveness of fibroblasts to extracellular signals. However, the cellular mechanisms underlying this phenomenon are not known. Aged dermal fibroblasts with reduced remaining replicative capacities demonstrated decreased epidermal growth factor (EGF)-induced cell migrative and cell proliferative capacities, as reported previously. Thus, as cells approach senescence, programmed in vivo or in vitro, EGF responsiveness is preferentially lost. To define the rate-limiting signaling event, we found that the activity of two different EGF receptor (EGFR)-signaling pathways to cell migration (phospholipase-C gamma) and/or mitogenesis (extracellular signal/regulated-mitogen-activated kinases) were decreased in near senescent cells despite unchanged levels of effector molecules. Aged cells presented decreased levels of EGFR, although insulin receptor and transferrin receptor levels were relatively unchanged. EGFR mRNA levels and production of new transcripts decreased during aging, suggesting that this preferential loss of EGFR was due to diminished production, which more than counteracts the reduced ligand-induced receptor loss. Since these data suggested that the decrement in EGF was rate-limiting, higher levels of EGFR were established in near senescent cells by electroporation of EGFR cDNA. These cells presented higher levels of EGFR and recovered their EGF-induced migration and proliferation responsiveness. Thus, the defect in EGF responsiveness of aged dermal fibroblasts is secondary to reduced EGFR message transcription. Our experimental model suggests that EGFR gene delivery might be an effective future therapy for compromised wound healing.

Inhibitory effects of human serum on human fetal skin fibroblast migration: migration-inhibitory activity and substances in serum, and its age-related changes

In order to clarify the environmental factors modulating cell migration, we investigated the effects of human serum on cell migration, and found that serum from adult donors strongly (by 48%) suppressed the migration of human fetal skin fibroblasts into a denuded area in a cell monolayer. Human serum from old donors inhibited cell migration more strongly than that from adult donors. Next, we investigated the properties of migration-inhibitory activity of human serum and serum proteins in order to identify migration-inhibitory substances. Human serum from adult donors strongly suppressed the migration of human fetal skin fibroblasts, although it stimulated cell proliferation more strongly than fetal bovine serum (FBS), indicating that the inhibitory effects of human serum on cell migration was not due to its toxic effects. The inhibition of cell migration by human serum was concentration dependent. It was demonstrated that the inhibition did not depend on the inhibitory effects of human serum on collagen synthesis. The migration-inhibitory activity was seen in fractions over 100 kDa, as determined by an ultrafiltration membrane, and no inhibitory activity was observed in fractions under 100 kDa. On the other hand, it was not detected either in fractions over 100 kDa or under 100 kDa in FBS. Among the over 100 kDa human serum proteins examined, gamma-globulin, alpha2-macroglobulin, and low density lipoprotein (LDL) suppressed fibroblast migration in a concentration-dependent manner. However, among the three, cell migration-inhibiting activity of gamma-globulin almost disappeared when cell migration was conducted in 10% FBS-supplemented medium. These results indicated that alplha2-macroglobulin and LDL were candidate substances for cell migration-inhibiting activity in human serum.

Fibroblast biology. Signals targeting the synovial fibroblast in arthritis

Fibroblast-like cells in the synovial lining (type B lining cells), stroma and pannus tissue are targeted by many signals, such as the following: ligands binding to cell surface receptors; lipid soluble, small molecular weight mediators (eg nitric oxide [NO], prostaglandins, carbon monoxide); extracellular matrix (ECM)-cell interactions; and direct cell-cell contacts, including gap junctional intercellular communication. Joints are subjected to cyclic mechanical loading and shear forces. Adherence and mechanical forces affect fibroblasts via the ECM (including the hyaluronan fluid phase matrix) and the pericellular matrix (eg extracellular matrix metalloproteinase inducer [EMMPRIN]) matrices, thus modulating fibroblast migration, adherence, proliferation, programmed cell death (including anoikis), synthesis or degradation of ECM, and production of various cytokines and other mediators [1]. Aggressive, transformed or transfected mesenchymal cells containing proto-oncogenes can act in the absence of lymphocytes, but whether these cells represent regressed fibroblasts, chondrocytes or bone marrow stem cells is unclear.