Exogenously added GPI-anchored tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) displays enhanced and novel biological activities

Immune Protection of Retroviral Vectors Upon Molecular Painting with the Complement Regulatory Protein CD59

Glycosylphosphatidylinositol anchoring is a type of post-translational modification that allows proteins to be presented on the exterior side of the cell membrane. Purified glycosylphosphatidylinositol-anchored protein can spontaneously re-insert into lipid bilayer membranes in a process termed Molecular Painting. Here, we demonstrate the possibility of inserting purified, recombinant CD59 into virus particles produced from a murine retroviral producer cell line. CD59 is a regulator of the complement system that helps protect healthy cells from the lytic activity of the complement cascade. In this study, we could show that Molecular Painting confers protection from complement activity upon murine retroviral vector particles. Indeed, increased infectivity of CD59-modified virus particles was observed upon challenge with human serum, indicating that Molecular Painting is suitable for modulating the immune system in gene therapy or vaccination applications.

Cell surface engineering using glycosylphosphatidylinositol anchored tissue inhibitor of matrix metalloproteinase-1 stimulates cutaneous wound healing

The balance between matrix metalloproteinases and their endogenous tissue inhibitors (TIMPs) is an important component in effective wound healing. The biologic action of these proteins is linked in part to the stoichiometry of TIMP/matrix metalloproteinases/surface protein interactions. We recently described the effect of a glycosylphosphatidylinositol (GPI) anchored version of TIMP-1 on dermal fibroblast biology. Here, cell proliferation assays, in vitro wound healing, electrical wound, and impedance measurements were used to characterize effects of TIMP-1-GPI treatment on primary human epidermal keratinocytes. TIMP-1-GPI stimulated keratinocyte proliferation, as well as mobilization and migration. In parallel, it suppressed the migration and matrix secretion of dermal myofibroblasts, and reduced their secretion of active TGF-β1. Topical application of TIMP-1-GPI in an in vivo excisional wound model increased the rate of wound healing. The agent positively influenced different aspects of wound healing depending on the cell type studied. TIMP-1-GPI counters potential negative effects of overactive myofibroblasts and enhances the mobilization and proliferation of keratinocytes essential for effective wound healing. The application of TIMP-1-GPI represents a novel and practical clinical solution for facilitating healing of difficult wounds.

Therapeutic effects of micheliolide on a murine model of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease and collagen-induced arthritis (CIA) is an animal model for RA. Micheliolide (MCL) is a novel compound with strong anti-inflammatory effects. The present study was conducted to evaluate the therapeutic effects of MCL on RA. Mice were randomly divided into four groups and the CIA model mice were treated with methotrexate (MTX), MCL and dimethyl sulfoxide. A score associated with the severity of arthritis was assigned on alternate days from the 22nd day for 60 days. Histopathological changes and the serum levels of cytokines were measured on day 85. The results demonstrated that the MCL treatment group had arthritis scores lower than the CIA group and higher than the MTX group; compared with the CIA group, MCL and MTX significantly reduced the swelling of the paws and suppressed the degeneration of articular cartilage. Expression levels of macrophage colony-stimulating factor (M-CSF), tissue inhibitors of metalloproteinases-1 (TIMP-1) and complement component 5a (C5/C5a) were lower in the mice with arthritis compared with normal mice, however, following treatment with MCL and MTX, all the mice exhibited significant recovery to differing degrees. Unlike the MTX group, the MCL group failed to recover the level of soluble intercellular adhesion molecule-1. In addition, the cytokine of B-lymphocyte chemoattractant (BLC) solely presented in the MCL group. These results suggest that MCL may be considered for use as a novel therapeutic treatment against RA and that changes in the expression of cytokines C5/C5a, TIMP-1, M-CSF and BLC may underlie the mechanism by which MCL effects changes in this disease.

Cytokine functions of TIMP-1

The tissue inhibitors of metalloproteinases (TIMPs) are well recognized for their role in extracellular matrix remodeling by controlling the activity of matrix metalloproteinases (MMPs). Independent of MMP inhibition, TIMPs act as signaling molecules with cytokine-like activities thereby influencing various biological processes including cell growth, apoptosis, differentiation, angiogenesis, and oncogenesis. Recent studies on TIMP-1's cytokine functions have identified complex regulatory networks involving a specific surface receptor and subsequent signaling pathways including miRNA-mediated posttranscriptional regulation of gene expression that ultimately control the fate and behavior of the cells. The present review summarizes the current knowledge on TIMP-1 as a cytokine modulator of cell functions, outlines recent progress in defining molecular pathways that transmit TIMP-1 signals from the cell periphery into the nucleus, and discusses TIMP-1's role as a cytokine in the pathophysiology of cancer and other human diseases.

Recombinant TIMP-1-GPI inhibits growth of fibrosarcoma and enhances tumor sensitivity to doxorubicin

Fibrosarcomas show a high incidence of recurrence and general resistance to apoptosis. Limiting tumor regrowth and increasing their sensitivity to chemotherapy and apoptosis represent key issues in developing more effective treatments of these tumors. Tissue inhibitor of metalloproteinase 1 (TIMP-1) broadly blocks matrix metalloproteinase (MMP) activity and can moderate tumor growth and metastasis. We previously described generation of a recombinant fusion protein linking TIMP-1 to glycosylphophatidylinositol (GPI) anchor (TIMP-1-GPI) that efficiently directs the inhibitor to cell surfaces. In the present report, we examined the effect of TIMP-1-GPI treatment on fibrosarcoma biology. Exogenously applied TIMP-1-GPI efficiently incorporated into surface membranes of human HT1080 fibrosarcoma cells. It inhibited their proliferation, migration, suppressed cancer cell clone formation, and enhanced apoptosis. Doxorubicin, the standard chemotherapeutic drug for fibrosarcoma, was tested alone or in combination with TIMP-1-GPI. In parallel, the influence of treatment on HT1080 side population cells (exhibiting tumor stem cell-like characteristics) was investigated using Hoechst 33342 staining. The sequential combination of TIMP-1-GPI and doxorubicin showed more than additive effects on apoptosis, while TIMP-1-GPI treatment alone effectively decreased “stem-cell like” side population cells of HT1080. TIMP-1-GPI treatment was validated using HT1080 fibrosarcoma murine xenografts. Growing tumors treated with repeated local injections of TIMP-1-GPI showed dramatically inhibited fibrosarcoma growth and reduced angiogenesis. Intraoperative peritumoral application of GPI-anchored TIMP-1 as an adjuvant to surgery may help maintain tumor control by targeting microscopic residual fibrosarcoma cells and increasing their sensitivity to chemotherapy

Treatment of dermal fibroblasts with GPI-anchored human TIMP-1 protein moderates processes linked to scar formation

Tissue inhibitors of metalloproteinases exhibit diverse physiological/biological functions including moderation of the proteolytic processing of growth factors and turnover of extracellular matrix. These various biological activities are linked in part to the stoichiometry of tissue inhibitor of metalloprotein/matrix metalloprotein (TIMP/MMP)/surface protein interactions. TIMP-1, a secreted protein, can be detected on the cell surface only through its interaction with surface-bound proteins. Proteins anchored by glycosylphosphatidylinositol (GPI), when purified and added to cells or tissues, are efficiently incorporated into their surface membranes. A GPI anchor was fused to TIMP-1 to focus defined concentrations of the inhibitory protein independently on the surface of primary dermal fibroblast cells. Exogenously added recombinant TIMP-1-GPI effectively inserted into the cell membrane of fibroblasts blocked the secretion of MMPs and markedly altered the stoichiometry of MMP association with the cell surface. TIMP-1-GPI treatment resulted in inhibition of fibroblast-reduced proliferation, and transiently reduced expression of fibrosis-associated genes. These effects were dose dependent. Treated cells also showed a more proapoptotic phenotype based on apoptotic assays and western blot analysis for apoptosis-associated protein expression. GPI-anchored TIMP-1 may represent a more effective version of the protein for use in therapeutic approaches to help control fibrosis and scar formation.

Recombinant GPI-anchored TIMP-1 stimulates growth and migration of peritoneal mesothelial cells

BACKGROUND

Mesothelial cells are critical in the pathogenesis of post-surgical intraabdominal adhesions as well as in the deterioration of the peritoneal membrane associated with long-term peritoneal dialysis. Mesothelial denudation is a pathophysiolocigally important finding in these processes. Matrix metalloproteinase (MMP) biology underlies aspects of mesothelial homeostasis as well as wound repair. The endogenous tissue inhibitors of metalloproteinases (TIMPs) moderate MMP activity.

METHODS AND FINDING

By modifying human TIMP-1 through the addition of a glycosylphosphatidylinositol (GPI) anchor, a recombinant protein was generated that efficiently focuses TIMP-1 on the cell surface. Treatment of primary mesothelial cells with TIMP-1-GPI facilitates their mobilization and migration leading to a dramatic increase in the rate of wound experimental closure. Mesothelial cells treated with TIMP-1-GPI showed a dose dependent increase in cell proliferation, reduced secretion of MMP-2, MMP-9, TNF-α and urokinase-type plasminogen activator (uPA), but increased tissue plasminogen activator (t-PA). Treatment resulted in reduced expression and processing of latent TGF-β1.

CONCLUSIONS

TIMP-1-GPI stimulated rapid and efficient in vitro wound closure. The agent enhanced mesothelial cell proliferation and migration and was bioactive in the nanogram range. The application of TIMP-1-GPI may represent a new approach for limiting or repairing damaged mesothelium.

Peritumoral administration of GPI-anchored TIMP-1 inhibits colon carcinoma growth in Rag-2 gamma chain-deficient mice

Exogenous application of recombinant TIMP-1 protein modified by addition of a glycosylphosphatidylinositol (GPI) anchor allows efficient insertion of the fusion protein into cell membranes. This 'cell surface engineering' leads to changes in the proteolytic environment. TIMP-1-GPI shows enhanced as well as novel in vitro biological activities including suppression of proliferation, reduced migration, and inhibition of invasion of the colon carcinoma cell line SW480. Treatment of SW480 tumors implanted in Rag (-/-) common gamma chain (-/-) C57BL/6 mice with peritumorally applied TIMP-1-GPI, control rhTIMP-1 protein, or vehicle shows that TIMP-1-GPI leads to a significant reduction in tumor growth.

TIMP-1-GPI in combination with hyperthermic treatment of melanoma increases sensitivity to FAS-mediated apoptosis

Resistance to apoptosis is a prominent feature of malignant melanoma. Hyperthermic therapy can be an effective adjuvant treatment for some tumors including melanoma. We developed a fusion protein based on the tissue inhibitor of matrix metalloproteinase-1 linked to a glycosylphosphatidylinositol anchor (TIMP-1-GPI). The TIMP-1-GPI-fusion protein shows unique properties. Exogenous administration of TIMP-1-GPI can result in transient morphological changes to treated cells including modulation of proliferation and decreased resistance to apoptosis. The effect of TIMP-1-GPI on the biology of melanoma in the context of a defined hyperthermic dose was evaluated in vitro. Clonogenic assays were used to measure cell survival. Gelatinase zymography determined secretion of MMP-2 and MMP-9. Monoclonal antibody against FAS/CD95 was applied to induce apoptosis. The expression of pro- and anti-apoptotic proteins and the secretion of immunoregulatory cytokines were then evaluated using Western blot and ELISA. TIMP-1-GPI combined with a sub-lethal hyperthermic treatment (41.8 degrees C for 2 h) suppressed tumor cell growth capacity as measured by clonogenic assay. The co-treatment also significantly suppressed tumor cell proliferation, enhanced FAS receptor surface expression increased tumor cell susceptibility to FAS-mediated killing. The increased sensitivity to FAS-induced apoptosis was linked to alterations in the apoptotic mediators Bcl-2, Bax, Bcl-XL and Apaf-1. The agent works in concert with sub-lethal hyperthermic treatment to render melanoma cells sensitive to FAS killing. The targeted delivery of TIMP-1-GPI to tumor environments in the context of regional hyperthermic therapy could be optimized through the use of thermosensitive liposomes.

[The role of matrix metalloproteinases and tissue inhibitors of metalloproteinases in invasion of tumours of neuroepithelial tissue]

Tumour invasion requires degradation of extracellular matrix components and migration of cells through degraded structures into surrounding tissues. Matrix metalloproteinases (MMP) constitute a family of zinc and calcium-dependent endopeptidases that play a key role in the breakdown of extracellular matrix, and in processing of cytokines, growth factors, chemokines and cell surface receptors. Their activity is regulated at the levels of transcription, activation and inhibition by tissue inhibitors of metalloproteinases (TIMP). Changes in expression of MMP and TIMP are implicated in tumour invasion, because they may contribute to both migration of tumour cells and angiogenesis. Alterations of MMP expression observed in brain tumours arouse interest in the development and evaluation of synthetic matrix metalloproteinase inhibitors as antitumour agents.

GPI-anchored TIMP-1 treatment renders renal cell carcinoma sensitive to FAS-meditated killing

The resistance of tumours to immune-mediated lysis has been linked to the biology of matrix metalloproteinases (MMPs), and specifically to the cell surface expression of MMPs by the tumour cell. The endogenous tissue inhibitors of metalloproteinases (TIMPs) exhibit diverse physiological/biological functions including the moderation of tumour growth, metastasis and apoptosis. These biologic activities are mediated in part by the stoichiometry of TIMP/MMP/cell surface protein interactions. A glycosylphosphatidylinositol (GPI) anchor was fused to TIMP-1 to focus defined concentrations of this inhibitory protein on the surface of three renal cell carcinoma (RCC) cell lines (RCC-26, RCC-53 and A498) independently of cell surface protein-protein interactions. Exogenously added TIMP-1-GPI efficiently inserted into the RCC cell membrane and dramatically altered the association of MMPs with the cell surface. TIMP-1-GPI treatment inhibited RCC proliferation and rendered the normally FAS-resistant RCC cells sensitive to FAS-induced apoptosis but did not alter perforin-mediated lysis by cytotoxic effector cells. The increased sensitivity to FAS-mediated apoptosis correlated with an alteration in the balance of pro- and antiapoptotic BCL-2-family proteins. By interfering with the proliferative capacity and inducing sensitivity to immune effector mechanisms GPI-anchored TIMP-1 may represent a more effective version of the TIMP-1 protein for therapeutic strategies.

Generation of GPI-linked CCL5 based chemokine receptor antagonists for the suppression of acute vascular damage during allograft transplantation

Limiting the acute vascular damage associated with leukocyte infiltration is a central issue in solid organ transplantation. The family of chemotactic cytokines (chemokines) helps to regulate leukocyte recruitment. Systemic treatment with the chemokine ligand-5 (CCL5) based antagonist Met-RANTES has previously shown to suppress acute damage to transplanted kidneys by blocking effector cell recruitment. To address problems associated with systemic long-term administration of chemokine receptor antagonists, a chemokine based reagent was designed to be integrated into endothelial surfaces of the organ just before transplantation. Proteins anchored by glycosylphosphatidylinositol (GPI), when purified and added to cells, are efficiently incorporated into their cell surface membranes. A series of modifications were introduced into the CCL5 protein to generate a functional antagonist. These included the addition of an N-terminal methionine group, a mutation to render the protein a dimer and a GPI signal sequence for surface expression. The resultant protein was stably expressed in CHO cells, GPI anchorage was confirmed and the protein purified by FPLC. Exogenously administered Met-CCL5(dimer)-GPI was efficiently inserted into the membrane of microvascular endothelial cells. The reagent is being tested in murine models of renal transplantation. The effect on subsequent immune induced damage will be assessed.