Heat shock of rabbit synovial fibroblasts increases expression of mRNAs for two metalloproteinases, collagenase and stromelysin

Metal oxide-coating PMMA or Talc as a new IR blocker inhibits IR-induced decrease of collagens in human dermal fibroblasts

OBJECTIVES

The purpose of this study was whether P/M or T/M inhibits IR-induced decrease of collagens in human dermal fibroblasts, using P/M or T/M blocked near-IR (NIR) transmittance significantly in spectrophotometer measurement.

METHODS

As metal oxides are effective inorganic molecules for intercepting IR radiation, we have developed metal oxide-coating PMMA (P/M) or Talc (T/M) as a new IR blocker. Inhibitory effect of the new IR blocker on collagen degradation was measured by gene and protein expressions of procollagens and MMPs, respectively, in IR-irradiated Hs68 cell line.

RESULTS

Using P/M or T/M inhibited IR-induced increases of MMP-1, MMP-3 and MMP-9, and IR-induced decreases of type 1 and 4 procollagen in a dose-dependent manner in dermal fibroblasts. In addition, using both P/M and T/M blocked the increase of cell media temperature induced by IR lamp.

CONCLUSION

The results suggest that P/M or T/M can inhibit decrease of collagens by blocking IR-induced heat transmission in human dermal fibroblasts.

Heat-induced MMP-1 expression is mediated by TRPV1 through PKCalpha signaling in HaCaT cells

BACKGROUND

Matrix metalloproteinase-1 (MMP-1) is considered a key initiator of collagen degradation in inflammatory responses. A heat-gated channel, transient receptor potential vanilloid type 1 (TRPV1), induces release of proinflammatory mediators. TRPV1 channels have been localized to the epidermis and we have recently suggested that they act as mediators of heat-induced MMP-1. The aim of this study was to investigate the signaling of TRPV1 in MMP-1 regulation by heat shock in human epidermal keratinocytes.

METHODS

Heat shock-induced MMP-1 expression was decreased by treatment with TRPV1 inhibitor. The heat-induced MMP-1 expression was suppressed by Gö6976 [calcium-dependent inhibitor] and staurosporine (ST, broad-spectrum PKC inhibitor), while rottlerin (ROT, calcium-independent PKCdelta inhibitor) had no effect. Also, transfection of PKCalpha siRNA decreased MMP-1 expression, whereas MMP-1 expression was not significantly affected in cells transfected with negative control siRNA, PKCbeta siRNA or PKCdelta siRNA.

RESULTS

We demonstrated that heat shock failed to induce MMP-1 expression in HaCaT cells cultured in calcium-free media. The heat-induced [Ca(2+)](i) increase was inhibited by Gö6976 and ST, but not by ROT. We also found that heat-induced phosphorylation of ERK, JNK and p38 MAPK in HaCaT cells, but capsazepine and ruthenium red had no effect on this activation. In addition to the role of TRPV1 in heat-induced MMP-1 expression, we also found that heat increased TRPV1 proteins in human skin in vivo.

CONCLUSIONS

Our results suggest that TRPV1 mediates heat shock-induced MMP-1 expression via calcium-dependent PKCalpha signaling in HaCaT cells.

Reactive oxygen species produced by NADPH oxidase, xanthine oxidase, and mitochondrial electron transport system mediate heat shock-induced MMP-1 and MMP-9 expression

In addition to ultraviolet radiation, human skin is also exposed to infrared radiation (IR) from natural sunlight. IR typically increases the skin temperature. This study examined whether or not heat shock-induced ROS stimulates MMPs in keratinocyte HaCaT cells. In HaCaT cells, heat shock was found to increase the intracellular ROS levels, including hydrogen peroxide and superoxide. The heat shock treatment induced MMP-1 and MMP-9, but not MMP-2, at the mRNA and protein levels. Moreover, heat shock caused the rapid activation of the three distinct MAPKs, ERK, JNK, and p38 kinase. The heat shock-induced expression of MMP-1 and MMP-9 was significantly suppressed by a pretreatment with the antioxidant NAC or catalase. On the other hand, SOD inhibited heat shock-induced activity of MMP-9 induction, but not MMP-1. A pretreatment with NAC or catalase, but not SOD, attenuated the phosphorylation of ERK, JNK, and p38 kinase by heat shock. The potential sites of ROS generation by heat shock along with its role in the heat shock-induced expression of MMP-1 and MMP-9 were next analyzed. These results indicate that heat shock-induced ROS is promoted via NADPH oxidase, xanthine oxidase, and mitochondria. Indeed, the NADPH oxidase and xanthine oxidase activities were increased by heat shock. Overall, the ROS produced by heat shock may play an important role in the heat shock-induced activation of MAPKs, which can induce MMP-1 and-9 expressions.

Retracted:Effect ofMeso-dihydroguaiaretic acid fromMachilus thunbergii Sieb et Zucc on MMP-1 expression in heat shock-induced cultured primary human fibroblasts

Ethanol and aqueous extracts of Machilus thunbergii Sieb et Zucc (Lauraceae) used traditionally for the treatment of a variety of diseases were screened in vitro for MMP-1 inhibitory actions. Meso-dihydroguaiaretic acid (MDGA) from the stem bark of M. thunbergii showed a significant inhibition of matrix metalloproteinase (MMP)-1 in primary human fibroblasts by heat shock-induced. This study investigated the effect of MDGA isolated from M. thunbergii on heat shock-induced premature skin aging. MDGA reduced the expression of MMP-1 at the protein level in a dose-dependent manner in heat shock-induced cultured primary human fibroblasts. Taken together, these results show that MDGA can prevent the harmful effects of heat (and/or IR) that lead to skin aging.

Augmentation of UV-induced skin wrinkling by infrared irradiation in hairless mice

Skin aging can be divided into intrinsic aging and photoaging. Sunlight is a major cause of photoaging, and is composed of ultraviolet (UV) and infrared (IR) radiation. Although the effects of UV radiation on skin aging have been widely studied, little is known about the biological effects of IR on the photoaging process in human skin. We found that chronic IR treatment induced wrinkles in hairless mice, and augments UV-induced wrinkle formation and UV-induced skin thickening in hairless mice. Histologically, we found that IR treatment augments UV-induced epidermal and dermal thickening, and that UV-induced increases of collagen and elastic fibers in dermis. Moreover, chronic IR treatment increased MMP-3 and MMP-13 mRNA expressions significantly in hairless mouse skin and augmented UV-induced MMP-3 and MMP-13 mRNA expressions and UV-induced MMP-2 and MMP-9 activities. From these results, we demonstrate that IR alone induces skin wrinkling and augments UV-induced wrinkle formation. Taken together, we suggest that IR plays an important role in the development of photoaging.

Heat modulation of tropoelastin, fibrillin-1, and matrix metalloproteinase-12 in human skin in vivo

Photoaged skin contains elastotic materials in the upper reticular dermis. This phenomenon is commonly known as solar elastosis. In this study, we investigated the effects of heat on the expression of tropoelastin and fibrillin-1, two main components of elastic fibers, and on matrix metalloproteinase (MMP)-12, the most active MMP against elastin, in human skin in vivo. Heat was found to increase tropoelastin mRNA and protein expression in the epidermis and in the dermis. Fibrillin-1 mRNA and protein expression were increased by heat in the epidermis, but were decreased in the dermis. We found that pre-treatment of skin with N-acetyl cysteine or genistein for 24 h prior to heat treatment inhibited the heat-induced expression of tropoelastin, but not of fibrillin-1. These data indicate that reactive oxygen species may play a role in tropoelastin expression by heat, but not in fibrillin-1 expression. We also found that heat treatment increases MMP-12 mRNA and protein expression in human skin. Our results suggest that the abnormal production of tropoelastin and fibrillin by heat in human skin and that their degradation by various MMP, such as MMP-12, may contribute to the accumulation of elastotic material in photoaged skin.

Heat shock-induced matrix metalloproteinase (MMP)-1 and MMP-3 are mediated through ERK and JNK activation and via an autocrine interleukin-6 loop

Although many studies have been performed to elucidate the molecular consequences of ultraviolet irradiation, little is known about the effect of infrared radiation on skin aging. In addition to photons, heat is likely to be generated as a consequence of infrared irradiation, and heat shock is widely considered to be an environmental stress. Here we investigated the effect of heat shock on the expressions of matrix metalloproteinase (MMP)-1, MMP-2, and MMP-3 in cultured human skin fibroblasts. Heat shock induced the expression of MMP-1 and MMP-3, but not MMP-2, at the mRNA and protein levels in a temperature-dependent manner, and caused the rapid activation of three distinct mitogen-activated protein kinases (MAPK), extracelluar signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK. The heat shock-induced MMP-1 and MMP-3 expression was suppressed by the inhibition of ERK and JNK but not by p38 MAPK inhibition. Furthermore, heat shock increased the synthesis and release of interleukin-6 (IL-6) into culture media. The specific inhibition of IL-6 using a monoclonal antibody against IL-6 greatly reduced the expression of MMP-1 and MMP-3 induced by heat shock. Taken together, our results suggest that ERK and JNK play an important role in the induction of MMP-1 and MMP-3 by heat shock and that the heat shock-induced expression of MMP-1 and MMP-3 is mediated via an IL-6-dependent autocrine mechanism.

Screening of stress enhancer based on analysis of gene expression profiles: enhancement of hyperthermia-induced tumor necrosis by an MMP-3 inhibitor

To improve the therapeutic benefit of hyperthermia, we examined changes of global gene expression after heat shock using DNA microarrays consisting of 12 814 clones. HeLa cells were treated for 1 h at 44 degrees C and RNA was extracted from the cells 0, 3, 6, and 12 h after heat shock. The 664 genes that were up or down-regulated after heat shock were classified into 7 clusters using fuzzy adaptive resonance theory (fuzzy ART). There were 41 genes in two clusters that were induced in the early phase after heat shock. In addition to shock response genes, such as hsp70 and hsp40, the stress response genes c-jun, c-fos and egr-1 were expressed in the early phase after heat shock. We also found that expression of matrix metalloproteinase 3 (MMP-3) was enhanced during the early response. We therefore investigated the role of MMP-3 in the heat shock response by examining HeLa cell survival after heat treatment in the presence and absence of an MMP-3 inhibitor, N-isobutyl-N-(4-methoxyphenylsulfonyl)glycylhydroxamic acid (NNGH) or N-hydroxy-2(R)-[[4- methoxysulfonyl](3-picolyl)amino]-3-methylbutaneamide hydrochloride (MMI270). The number of surviving cells 3 days after heat treatment significantly decreased, reaching 3.5% for NNGH and 0.2% for MMI270. These results indicate that the MMP-3 inhibitors enhanced heat shock-induced cell death and behaved as stress enhancers in cancer cells. This valuable conclusion was reached as a direct result of the gene expression profiling that was performed in these studies.

Heat shock-mediated transient increase in intracellular 3',5'-cyclic AMP results in tumor specific suppression of membrane type 1-matrix metalloproteinase production and progelatinase A activation

We have previously reported that heat shock suppresses the production and gene expression of membrane type 1-matrix metalloproteinase (MT1-MMP) and thereby inhibits the activation of progelatinase A/proMMP-2 in human fibrosarcoma HT-1080 cells and human squamous carcinoma A431 cells and SAS cells (Sato et al. Biochem Biophys Res Commun 1999; 265: 189-93). In an effort to clarify the heat shock-mediated signal transduction pathways, an intracellular cAMP level was found to be transiently augmented in the heat shocked HT-1080 cells. When HT-1080 cells were pretreated with cAMP elevating reagents, forskolin and dibutyryl cAMP for 4 h instead of heat shock and then maintained in a fresh medium, the production and gene expression of MT1-MMP were similarly suppressed. The MT1-MMP-mediated activation of proMMP-2 was also inhibited in the forskolin- and dibutyryl cAMP-treated HT-1080 cells. Furthermore, the transiently augmented cAMP by forskolin as well as heat shock interfered with in vitro invasive activity of HT-1080 cells. In contrast, in normal human fibroblasts neither heat shock nor cAMP elevating reagents altered the concanavalin A-augmented MT1-MMP production and proMMP-2 activation. These results suggest that a transient increase in intracellular cAMP is a critical signal for heat shock to induce tumor specific-suppression of MT1-MMP production and proMMP-2 activation.

The stressed synovium

This review focuses on the mechanisms of stress response in the synovial tissue of rheumatoid arthritis. The major stress factors, such as heat stress, shear stress, proinflammatory cytokines and oxidative stress, are discussed and reviewed, focusing on their potential to induce a stress response in the synovial tissue. Several pathways of stress signalling molecules are found to be activated in the synovial membrane of rheumatoid arthritis; of these the most important examples are heat shock proteins, mitogen-activated protein kinases, stress-activated protein kinases and molecules involved in the oxidative stress pathways. The expression of these pathways in vitro and in vivo as well as the consequences of stress signalling in the rheumatoid synovium are discussed. Stress signalling is part of a cellular response to potentially harmful stimuli and thus is essentially involved in the process of synovitis. Stress signalling pathways are therefore new and promising targets of future anti-rheumatic therapies.

Heat shock suppresses membrane type 1-matrix metalloproteinase production and progelatinase A activation in human fibrosarcoma HT-1080 cells and thereby inhibits cellular invasion

Expression of membrane type-1 matrix metalloproteinase (MT1-MMP) is closely correlated with tumor invasiveness. We investigated the effect of hyperthermia on the production of MT1-MMP in human fibrosarcoma HT-1080 cells. Heat shock at 42 degrees C suppressed the production and gene expression of MT1-MMP in HT-1080 cells. Heat shock-induced suppression of MT1-MMP production resulted in the inhibition of progelatinase A (proMMP-2) activation and the increased release of tissue inhibitor of metalloproteinases 2 from cell surface. In addition, in vitro tumor invasion assay in a Matrigel model indicated that heat shock inhibited the invasive activity of HT-1080 cells. These results suggest that heat shock preferentially suppresses the production of MT1-MMP and thereby inhibits proMMP-2 activation, events which subsequently inhibit tumor invasion. Therefore, heat shock shows an anti-invasive effect along with the known mechanism of inhibiting tumor growth.

Immunolocalization of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human subconjunctival tissues

PURPOSE

To evaluate the roles of fibroblast proteins in the remodeling of the subconjunctival connective tissue, we immunohistochemically assessed the expression of matrix metalloproteinases (MMP)-1 and -2, and the tissue inhibitors of matrix metalloproteinases (TIMP)-1 and -2 in cultured human subconjunctival fibroblasts and in normal and healing human subconjunctival connective tissue.

METHODS

Cultured fibroblasts derived from human subconjunctival connective tissue and surgical specimens of normal and healing conjunctiva were immunostained with monoclonal antibodies directed against human MMPs and TIMPs and examined by light and electron microscopy.

RESULTS

In the cultured fibroblasts, MMP-1 and TIMP-1 antibodies stained the cytoplasm in a fine granular pattern, suggesting localization of those proteins in the endoplasmic reticulum (ER) and Golgi apparatus. Antibodies to MMP-2 and TIMP-2 reacted with fibroblast cytoplasm in a granular pattern. Electron microscopy of those fibroblasts revealed MMP-1 and TIMP-1 immunoreactivity in the ER cisternae or on the membrane of the ER. In surgical samples, MMP-1 and TIMP-1 were immunohistochemically detected in healing subconjunctival tissue, but not in conjunctival epithelium or normal subconjunctival tissue.

CONCLUSIONS

MMPs and TIMPs may be involved in remodeling of subconjunctival connective tissue and in fibroblast population after surgical interventions. These proteins may play a crucial role in the post-operative fibrotic process occurring during scar formation in subconjunctival tissue.

Expression of matrix metalloproteinases and their inhibitors in aneurysms and normal aorta

BACKGROUND

Abdominal aortic aneurysms (AAAs) are characterized by degradation of collagen and elastin resulting from increases in matrix metalloproteinase (MMP) activity. Previous authors have identified isolated increases in expression of specific MMPs in AAAs, but none have compared relative levels of expression of particular MMPs to one another or to those of their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs). This study proposes to quantify relative mRNA levels for interstitial collagenase (MMP-1), 72 kd type IV collagenase (MMP-2), 92 kd type IV collagenase (MMP-9), TIMP-1, and TIMP-2 in normal aorta (NA) and AAA to provide insight as to the relative importance of each in aneurysm formation.

METHODS

Competitive polymerase chain reactions (PCRs) with gene-specific external standards and cDNA derived from AAAs (n = 8; mean age, 67.4 years) and NA (n = 5; mean age, 40.6 years) were used to quantify mRNA levels. Results were normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA levels, determined by means of competitive PCR, and compared by means of Mann-Whitney statistics.

RESULTS

Significant increases in MMP mRNA expression in AAA over NA were observed for MMP-1 (3.64 versus 0.3, p = 0.007), MMP-9 (78.03 versus 3.35, p = 0.003), TIMP-1 (835.32 versus 477.2, p = 0.027), and TIMP-2 (18.09 versus 4.14, p = 0.003). The ratio of MMP to TIMP mRNA levels was higher in AAA than NA (0.135 versus 0.045, p = 0.018).

CONCLUSIONS

Increases in expression of MMP-1, MMP-9, and MMP/TIMP ratios may result in increased proteolysis and matrix degradation, which characterize AAAs. MMP-9 appears to be the predominant metalloproteinase expressed in AAA, because its mRNA levels were more than 20 times and 2 times higher than those of MMP-1 and MMP-2, respectively. TIMP-1 mRNA levels were in molar excess to those of any of the metalloproteinases studied.

Expression of stromelysin 1 in human astrocytoma cell lines

In a wide variety of tumor types, the expression of stromelysin 1 which is one of the matrix metalloproteinases (MMPs) has been shown to correlate with tumor invasion. However, little is known about the distribution of stromelysin in human brain tumors. We have previously shown that a correlation exists between the type IV collagenases, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 transcripts and in vitro invasiveness among 7 human astrocytoma cell lines. In the present study, we analyzed the expression of stromelysin 1 among the same panel of human astrocytoma cell lines and human fibroblasts by northern blot analyses and in situ hybridization. Northern blot analysis demonstrated that SF-126 and U87 MG expressed high level stromelysin 1 transcripts. Following heat shock stimulation, the stromelysin 1 transcript was up-regulated in U87 MG astrocytoma cells. In situ hybridization analysis showed specific intracytoplasmic localization of mRNA for stromelysin in these astrocytoma cell lines. By casein zymography, we have determined that both SF-126 and U87 MG secreted stromelysin 1 protein. We conclude that stromelysin 1 is expressed by certain human astrocytoma cell lines, and this study confirms the importance of continuing to characterize the proteolytic enzyme profile of these tumors to fully understand the molecular mechanisms involved in astrocytoma invasiveness.

In vivo effects of stromelysin on the composition and physical properties of rabbit articular cartilage in the presence and absence of a synthetic inhibitor

OBJECTIVE

To characterize the effects of intraarticular injection of recombinant human stromelysin (SLN) on the matrix composition and physical properties of cartilage from lapine stifle joints and the modulation of these effects by the systemic administration of an N-carboxyalkyl synthetic matrix metalloproteinase inhibitor, L-696,418.

METHODS

Female 6-8-week-old New Zealand white rabbits received an intraarticular injection of 100 micrograms activated SLN in 1 stifle joint and buffer in the contralateral control knee; these animals were killed after 1 hour. A separate group of animals received an intravenous injection of either 30 mg/kg L-696,418 or buffer prior to intraarticular injection of SLN. Joints were dissected and analyzed for proteoglycan (PG) loss into joint fluid, tissue biochemical composition, and histology by toluidine blue or anti-VDIPEN antibody staining, or were frozen for physical property analysis. Disks of femoropatellar groove cartilage were harvested from the stifle joint and tested in uniaxially confined compression for determination of electromechanical and mechanical properties.

RESULTS

Lapine stifle joints that received injection of SLN without systemic administration of L-696,418 showed a 13-fold increase in loss of PG into synovial fluid. Cartilage from these joints showed significant decreases in streaming potential at 1 Hz and electrokinetic coupling coefficient, but no change in equilibrium modulus, dynamic stiffness, or hydraulic permeability. Systemic treatment with L-696,418 resulted in a significant decrease in loss of PG into joint fluid and elimination of changes in cartilage high-frequency streaming potential and coupling coefficient in joints that were injected with SLN.

CONCLUSION

The 1-hour exposure to SLN in vivo resulted in loss of PG and exposure of the VDIPEN epitope of the aggrecan core protein in the superficial region of the tissue near the articular surface. This highly localized degradation resulted in electromechanical behavior changes, but little or no change occurred in mechanical properties. Systemic administration of L-696,418 significantly decreased loss of PG from cartilage and prevented the highly localized tissue degradation and the resultant changes in electromechanical behavior caused by intraarticular SLN injection.

Simian virus 40 transformation alters the actin cytoskeleton, expression of matrix metalloproteinases and inhibitors of metalloproteinases, and invasive behavior of normal and ataxia-telangiectasia human skin fibroblasts

Alterations in the actin cytoskeleton of normal cells result in changes in cell shape and adhesiveness and induce expression of matrix-degrading matrix metalloproteinases. We examined the effect of simian virus 40 transformation of normal and ataxia-telangiectasia human skin fibroblasts, a process that produces actin reorganization, altered cell morphology, and altered cell behavior, on expression of genes of the matrix metalloproteinase and tissue inhibitor of metalloproteinases gene families. Simian virus 40 transformation induced collagenase-1 gene expression; in contrast, stromelysin-1, 72-kDa gelatinase (gelatinase A), tissue inhibitor of metalloproteinases-1, and tissue inhibitor of metalloproteinases-2 genes were repressed. Transformation also altered the response of the fibroblasts to 12-O-tetradecanoylphorbol-13-acetate. Collagenase mRNA was induced in 12-O-tetradecanoylphorbol-13-acetate treated transformed cells up to 50-fold more than in untreated transformed cells or in 12-O-tetradecanoylphorbol-13-acetate treated untransformed parent cells. In contrast, 12-O-tetradecanoylphorbol-13-acetate did not overcome the attenuated expression of stromelysin-1 in the simian virus 40 transformants. In addition, 92-kDa gelatinase (gelatinase B) was induced by 12-O-tetradecanoylphorbol-13-acetate only in the simian virus 40 transformants. The responses of gelatinase A and tissue inhibitor of metalloproteinases-1 to 12-O-tetradecanoylphorbol-13-acetate were unchanged. The pattern of altered proteinase expression after transformation was accompanied by a phenotypic alteration in cell invasion. The simian virus 40 transformants exhibited enhanced invasiveness through a basement-membrane-like matrix. These data demonstrate that enhanced invasiveness in simian virus 40 transformed cells is accompanied by changes in actin organization and expression of proteinases and inhibitors, as well as in the balance between proteinases and inhibitors in favor of proteinases.

Heat shock of human synovial and dermal fibroblasts induces delayed up-regulation of collagenase-gene expression

We investigated the effect of heat shock on the expression of the collagenase gene in normal human synovial and dermal fibroblasts. Heat shock (42-44 degrees C for 1 h) caused a marked increase in heat-shock protein 70 (HSP-70) mRNA levels, followed by a delayed increase in collagenase mRNA levels, in both cell types. Pretreatment with cycloheximide had no effect on the heat-shock-induced increase in HSP-70 mRNA expression, but abrogated the induction of collagenase mRNA during the recovery. To study the mechanisms of collagenase-gene induction by heat shock, the transcriptional activity of a collagenase-promoter-driven chloramphenicol acetyltransferase (CAT) reporter gene was examined in transient transfection experiments. Heat shock was followed by a > 2-fold increase in CAT activity driven by a 3.8 kb fragment of the collagenase promoter, or by a construct containing an AP-1 binding site. A mutation in the AP-1 binding site abolished the effect of heat shock. Electrophoretic-mobility-shift assays revealed a marked increase in DNA-binding activity specific for the AP-1 binding site in nuclear extracts prepared from synovial fibroblasts recovering from heat shock. These results indicate that heat shock causes a delayed increase in collagenase-gene expression in human fibroblasts, and suggests that this stimulation involves, at least in part, transcriptional activation through an AP-1 binding site. Heat shock appears to initiate a programme of cellular events resulting in collagenase-gene expression, and therefore may contribute to connective-tissue degradation in disease states.

Changes in cartilage composition and physical properties due to stromelysin degradation

OBJECTIVE

To determine the effects of stromelysin treatment on biochemical, histologic, and swelling characteristics of intact cartilage explants and to correlate these effects with changes in the functional physical properties of the tissue.

METHODS

Bovine articular cartilage explants were cultured for up to 3 days in the presence or absence of recombinant human stromelysin (SLN). Damage to matrix proteoglycans and collagens was assessed and characterized by N-terminal sequencing and Western blot analysis, respectively. Explants were mechanically tested to assess the ability of the tissue to withstand cyclic and static compressive loads.

RESULTS

Treatment with SLN resulted in a time- and dose-dependent loss of proteoglycans from cartilage explants, with significant loss seen after 3 days of exposure to 20 nM SLN: Histology indicated that initial loss of proteoglycans occurred in regions near the tissue surface and proceeded inward with increasing time of SLN exposure. SLN treatment resulted in degradation of matrix collagen types IX and II, and a concomitant increase in tissue swelling. This matrix degradation resulted in severe alterations in functional physical properties of the tissue, including compressive stiffness. The initial, focal loss of proteoglycans that resulted from SLN treatment was most accurately detected with high-frequency streaming potential measurements.

CONCLUSION

Exposure of intact cartilage to SLN caused specific, molecular-level degradation of matrix molecules, which resulted in changes in the swelling behavior and marked deterioration of functional physical properties of the tissue.

Immunolocalization of collagenase and TIMP in healing human burn wounds

Degradative events in remodeling connective tissues are mediated through the actions of one or more members of the matrix metalloproteinase family. Conversely, members of the tissue inhibitors of metalloproteinase (TIMP) family act to attenuate proteolysis. Because collagenase and TIMP are rapidly secreted into the extracellular matrix following their biosynthesis and may not remain near their cell of origin, we undertook an immunohistochemical examination of human burn injuries to establish the distribution of these proteins during acute wound repair. Immunostaining for collagenase and TIMP was markedly increased within the wound bed but not in adjacent regions of histologically normal skin. Immunoreactive collagenase was first noted at the eschar-dermal interface by day 3 after injury and became very prominent in the dermis from day 5 to day 17. By day 5, focal patches of immunoreactive collagenase were found at the epidermal-dermal junctions at the wound margins. Within the wound bed, intense staining for collagenase was noted in the connective tissue surrounding the surviving epithelial appendages and around blood vessels. Immunoreactive TIMP was detected by day 2 both in the dermis and the overlying eschar but rapidly assumed the same interfacial pattern as described for collagenase. Staining for TIMP was only sporadically found at the dermal-epidermal margins and surrounding surviving epithelial appendages. Like collagenase, TIMP was prominently localized about vascular structures. These studies demonstrate that, in acute wounds, immunoreactive collagenase and TIMP are generally increased throughout the area of injury but particularly so at interface zones including eschar-dermis, epidermis-dermis, appendages-dermis, and around vascular structures.

Localization of mRNAs representing interstitial collagenase, 72-kda gelatinase, and TIMP in healing porcine burn wounds

The process of wound healing sets in motion a complex and dynamic series of events, which includes the remodeling of the extracellular matrix. Degradation of matrix macromolecules is mediated through the actions of the matrix metalloproteinase family. Conversely, the actions of this enzyme family are regulated by tissue inhibitors of metalloproteinases (TIMPs). In this study, we have developed riboprobes derived from human cDNAs representing collagenase, 72-kDa gelatinase, and TIMP and have found them to be sufficiently specific and sensitive for use in in situ hybridization studies of porcine burn wounds. Expression of these mRNAs, although not seen in uninjured skin, was found to be a predictable and locally distinct event in wound repair. Transcripts for collagenase and TIMP but not 72-kDa gelatinase were detected at the resurfacing epithelial margin; label was also detected in and around follicular epithelium within the wound bed. Transcripts for both metalloenzymes and TIMP were found throughout the viable dermis and subcutaneous tissues underlying the wound bed. However, expression of 72-kDa gelatinase was most prominent in the superficial dermis adjacent to the resurfacing epidermis at the wound margin. Collagenase and TIMP transcripts were particularly prominent in a perivascular pattern in the dermis and in the connective tissue network surrounding adipocytes in the subcutaneous zone. Numerous cell types appeared to be involved, including keratinocytes, fibroblasts, macrophages, and endothelial cells. Future exploitation of this porcine thermal injury model is likely to provide information about the spatial and temporal patterns of matrix metalloproteinase and TIMP expression in cutaneous wound healing.

Localization of mRNAs representing collagenase and TIMP in sections of healing human burn wounds

Interstitial collagenase, a matrix metalloproteinase, is known to be actively involved in remodeling of cutaneous tissues including those affected by trauma, neoplasia, and inflammation. Conversely, collagenase activity is blocked by tissue inhibitor of metalloproteinases (TIMP). Because both collagenase and TIMP are rapidly secreted into the extracellular matrix, their sites of synthesis remain ambiguous. To determine the site and sequence of collagenase and TIMP expression in cutaneous wound repair, we examined partial and full thickness excisions of human burn wounds representing days 2 to 34 postinjury. Prominent labeling for collagenase and TIMP was detected in epithelial cells at the burn margin and at the edges of surviving hair follicles and eccrine sweat structures in the wound bed. Within the dermis, cells expressing collagenase and TIMP were at first perivascular in location and later appeared at the interface zone between viable and nonviable dermis. A diversity of cell types including macrophages, fibroblasts, endothelial cells, and keratinocytes appeared to express mRNAs for collagenase and TIMP. Little if any labeling was detected in necrotic regions, in adjacent nonwounded dermis, or epidermis. Our data indicate that collagenase and TIMP are temporally and spatially regulated during cutaneous wound repair.

Matrix metalloproteinases: a review

Matrix metalloproteinases (MMPs) are a family of nine or more highly homologous Zn(++)-endopeptidases that collectively cleave most if not all of the constituents of the extracellular matrix. The present review discusses in detail the primary structures and the overlapping yet distinct substrate specificities of MMPs as well as the mode of activation of the unique MMP precursors. The regulation of MMP activity at the transcriptional level and at the extracellular level (precursor activation, inhibition of activated, mature enzymes) is also discussed. A final segment of the review details the current knowledge of the involvement of MMP in specific developmental or pathological conditions, including human periodontal diseases.

Basic calcium phosphate crystals cause coordinate induction and secretion of collagenase and stromelysin

Synovial fluid basic calcium phosphate crystals (BCP) are often found in severely degenerated joints. Crystalline BCP is a growth factor stimulating fibroblast mitogenesis and acting as a competence factor similar to platelet-derived growth factor. In human fibroblasts (HF), the synthesis of collagenase and stromelysin is coordinately induced after stimulation with a variety of cytokines and growth factors. We sought to determine whether BCP, like other growth factors, might induce proteases that would damage articular tissue. Northern blot analysis of mRNA for collagenase and stromelysin in HF stimulated with BCP was performed. Secreted enzymes were analyzed by immunoblot using a monoclonal antibody to collagenase and by immunoprecipitation using a polyclonal antibody to stromelysin. Stromelysin activity was confirmed using casein substrate gels. A significant, dose-dependent accumulation of collagenase and stromelysin message was evident after 4 h and continued for at least 24 h in BCP-stimulated cultures. Forty-nine and 54 kD proteins immunoreacting with collagenase antibody were identified in the conditioned media (CM) from BCP-stimulated cultures while 50 and 55 kD proteins were identified by immunoprecipitation with stromelysin antibody. Collagenase activity was increased significantly in the CM from BCP treated cells; casein substrate gels showed casein degrading bands at molecular weights consistent with stromelysin. BCP stimulates coordinate induction of collagenase and stromelysin which may mediate the joint destruction associated with these crystals.

Transforming growth factor-beta 1 rapidly induces Hsp70 and Hsp90 molecular chaperones in cultured chicken embryo cells

In this report we show that: (1) molecular chaperones in the heat shock protein (hsp) family are a new class of cellular proteins induced by Transforming Growth Factor-beta 1 (TGF beta), a cytokine present in serum, (2) rapid induction of Hsc70 precedes a general increase in protein synthesis and may be a preparatory event, (3) TGF beta is a potent regulator of overall protein synthesis in chicken embryo cells (CEC), and (4) isoforms of Hsp90 with different biochemical properties exist, raising the possibility that they may have different functions. TGF beta can substitute for serum in stimulating synthesis of members of the Hsp90 and Hsp70 families of stress proteins, whereas other cytokines, including PDGF, FGF, and EGF, were not effective nor did they enhance the stimulatory effect of TGF beta on the hsp's. Analysis of the induction of hsp's using one- and two-dimensional polyacrylamide gel electrophoresis indicated that members of the Hsp70 family of molecular chaperones were induced rapidly by TGF beta, reaching maximum rates of accumulation by 5 hours of treatment. Total protein synthesis increased more slowly, undergoing an approximately twofold increase in 24 hours. Using a modified protocol for two-dimensional gel electrophoresis, the Hsp90 protein family was separated into four isoelectric forms, two of which were phosphorylated (Hsp90-2 and -4). These phosphorylated isoforms turned over faster than the unphosphorylated forms of Hsp90. All four isoforms were heat inducible, but only Hsp90-2 and -3 were induced rapidly by TGF beta, again within 5 hours of treatment. The effects of serum on these protein families were similar to those of TGF beta, suggesting that this cytokine may be the serum component primarily responsible for up-regulating members of the Hsp90 and Hsp70 families. We hypothesize that cells rapidly increase their chaperoning capacity for newly synthesized polypeptides in preparation for an increase in the rate of synthesis of proteins up-regulated by TGF beta.

Spontaneous expression of immediately-early response genes c-fos and egr-1 in collagenase-producing rheumatoid synovial fibroblasts

In view of the important role of interstitial collagenase in the pathogenesis of rheumatoid arthritis (RA), we studied the expression of fibroblast-type collagenase in rheumatoid synovium and searched for its potential transcription factors, namely the oncoprotein c-fos and the early-growth-response gene-1 (egr-1), an inducible zinc-finger encoding gene. Elevated levels of RNA sequences complimentary to c-fos and egr-1 cDNA probes could be detected in cytoplasmic extracts of collagenase-expressing synovial fibroblast-like cells when compared to equivalent RNA amounts isolated from control fibroblasts. Utilizing immunocytochemistry, immunoreactivity for c-fos oncoprotein was found in 13 of 19 joint specimens obtained from patients with active RA. These oncoprotein data were positively correlated to the collagenase expression in the same specimens. Moreover, immunohistochemical analysis confirmed the localization of both oncoprotein c-fos and fibroblast-type collagenase within synovial fibroblast-like cells attached to bone erosions.

Secretion of stromelysin by cultured dermal papilla cells: differential regulation by growth factors and functional role in mitogen-induced cell proliferation

To understand better the molecular nature of the epithelial-mesenchymal interactions that govern folliculogenesis and hair growth, we have studied the behavior of cultured rat dermal papilla cells (rDP), the mesenchymal component of the hair follicle. Basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) both potentiated the growth of rDP in culture, and transforming growth factor-beta (TGF-beta) inhibited rDP proliferation. Biosynthetic labeling studies demonstrated that both PDGF and bFGF induced synthesis of a major secreted protein(s) with Mr = 55-60 kD. It was noted that PDGF and bFGF differentially regulated synthesis of this major secreted protein; PDGF-mediated induction was found to be transient, while bFGF allowed prolonged synthesis of the protein. Sodium dodecyl sulfate (SDS)-substrate gel analysis of rDP-conditioned media revealed that this protein is a metalloproteinase with casienolytic activity and Mr approximately 51 kD (unreduced). We have identified the growth factor-regulated rDP protein as the matrix metalloproteinase stromelysin by immunoprecipitation. Northern analysis established that increased secretion of stromelysin was accompanied by an increased expression of stromelysin-specific mRNA. Remarkably, stromelysin antisera interfere with stimulation of dermal papilla cell growth, demonstrating that stromelysin production serves a functional role in mitogen-induced proliferation in these cells. These findings provide insight into the mechanism by which the connective tissue remodeling required for formation of hair embryonically and the postembryonic hair cycle may be regulated.

Interleukin 1 and phorbol 12-myristate 13-acetate induce collagenase and PGE2 production through a PKC-independent mechanism in chondrocytes

In the present study we demonstrate that interleukin 1 (IL 1) and phorbol 12-myristate 13-acetate (PMA) stimulate collagenase production by bovine chondrocytes in monolayer culture. Since it has been well established that PMA stimulates protein kinase C (PKC), we examined whether IL 1 and PMA also stimulate PKC in chondrocytes. In agreement with other studies, PMA induced the translocation of PKC, reflecting PKC activation by PMA. In contrast, IL 1 did not induce the translocation of PKC. Both IL 1 and PMA stimulated the release of [14C]arachidonic acid from chondrocyte phospholipids, suggesting that both agents stimulate phospholipase A2 (PLA2). Concomitantly, IL 1 and PMA also induced a pronounced increase in the production of PGE2. Pre-incubation of chondrocytes with staurosporine, a PKC inhibitor, did not affect the stimulation of collagenase production by IL 1 and only minimally that induced by PMA. Similarly, high concentrations of staurosporine did not inhibit prostaglandin E2 (PGE2) production induced by IL 1 or PMA. These data show that IL 1 and PMA stimulate the PLA2 pathway and collagenase production, however, these processes can occur in the absence of PKC activation.

In situ hybridization studies of stromelysin and collagenase messenger RNA expression in rheumatoid synovium

Destructive joint changes in rheumatoid arthritis (RA) are thought to be mediated in part by the neutral proteinases collagenase and stromelysin. Collagenase messenger RNA (mRNA) has been previously localized to the synovial lining layer. In this study, synovial tissue from 8 patients with RA and 2 patients with osteoarthritis was examined for proteinase production by in situ hybridization. Stromelysin mRNA localized predominantly to the synovial lining layer cells. In serial sections, collagenase mRNA was shown to be localized to the same tissue areas as those producing stromelysin mRNA, and grain counts revealed a direct correlation between production of stromelysin mRNA and production of collagenase mRNA. All patients with RA were producing collagenase and stromelysin mRNA in detectable amounts. One of 2 osteoarthritis patients was producing these metalloproteinases, but in levels below those found in the RA patients. These data support the identity of the synovial lining cells as the major synovial cells producing collagenase and stromelysin in RA and provide new evidence for the coordinate production of collagenase and stromelysin in RA in vivo.

Induction of plasminogen activator inhibitor 1 biosynthesis by hyperthermia

Hyperthermia is a clinical sign of inflammation and constitutes in itself an adaptive defense mechanism. The fibrinolytic system, a highly regulated proteolytic system, is involved in inflammatory processes. Plasminogen activator inhibitor 1 (PAI-1) is the principal inhibitor of the two activators of the fibrinolytic system: tissue- and urokinase-type PAs (t-PA and u-PA). Our present paper provides the first evidence that hyperthermia can directly induce PAI-1. A moderate heat stress, sufficient to induce heat shock protein 70 mRNA approximately 100-fold, resulted in a two- to three-fold increase in functionally active PAI-1 in the conditioned medium of human HT-1080 fibrosarcoma and Hep G2 hepatoma cells. Exposure of these cells to 42 degrees C led to a similar two-fold and two- to five-fold induction of PAI-1 mRNA expression in HT-1080 and Hep G2 cells, respectively, as has been determined by using both oligo d(T) selected and total RNA preparations. These results suggest that the observed increase in PAI-1 accumulation is due to an induction of PAI-1 biosynthesis. Run-on transcription analysis indicates that the induction of PAI-1 biosynthesis by hyperthermia is mediated by a stimulation of PAI-1 gene transcription. No significant effect of hyperthermia was found on t-PA or u-PA at the level of antigen accumulation, mRNA, and gene transcription in human HT-1080 fibrosarcoma cells. These results point to an additional regulatory mechanism of fibrinolysis in the context of inflammation.

Interleukin 1 induces the expression of a heat-shock gene in chondrocytes

The presence of T cells and antibodies reactive with heat-shock proteins (hsps) in the joints of patients with rheumatoid arthritis may indicate a role of hsps in this disease. In the present study we examined whether increased temperature and interleukin 1 (IL 1), both of which are elevated in arthritic joints, induced the expression of two hsp70 genes in bovine chondrocyte cultures. We found that heat shock resulted in increased expression of constitutive and inducible hsp70 mRNA species. IL 1 and phorbol 12-myristate 13-acetate (PMA) also induced an increase in the constitutive hsp70 mRNA species, but without affecting the expression of the inducible hsp70 gene. The increase induced by IL 1 was observed only after 3 h, whereas increases induced by PMA were observed within 1 h. For all treatments, the hsp70 mRNA decreased by 24 h. Heat treatment of chondrocytes did not affect levels of collagenase and caseinase activity in the medium, nor did it alter proteoglycan synthesis by these cells.

Enhanced expression of procollagenase in ataxia-telangiectasia and xeroderma pigmentosum fibroblasts

Ataxia-telangiectasia and xeroderma pigmentosum are human hereditary diseases in which patients are cancer prone and demonstrate increased sensitivity to DNA damage by ionizing and ultraviolet radiation, respectively. In culture, both ataxia-telangiectasia and xeroderma pigmentosum skin fibroblasts show increased synthesis and secretion of the extracellular matrix proteins fibronectin and collagen. To determine whether these differences in protein production result from fundamental abnormalities in regulation of genes associated with cellular interactions, we compared the effects of trifluoperazine and 12-O-tetradecanoylphorbol-13-acetate on expression of the extracellular matrix-degrading metalloproteinases, procollagenase and prostromelysin, by normal, ataxia-telangiectasia, and xeroderma pigmentosum fibroblasts. After trifluoperazine treatment the overall levels of these metalloproteinases were much greater in three ataxia-telangiectasia cell strains and in cells from xeroderma pigmentosum complementation groups A and D than in normal cells. In contrast, cells from xeroderma pigmentosum complementation group C produced only slightly more procollagenase than normal cells. 12-O-tetradecanoylphorbol-13-acetate also induced higher than normal levels of procollagenase in some ataxia-telangiectasia and xeroderma pigmentosum strains, but less than that induced by trifluoperazine. Because increased extracellular accumulation of matrix-degrading enzymes has long been implicated in metastatic progression, this altered expression of procollagenase and prostromelysin in ataxia-telangiectasia and xeroderma pigmentosum cells could play an important role in the pathogenesis of various tumors in individuals with these genetic diseases.

Cytoskeletal dynamics in rabbit synovial fibroblasts: I. Effects of acrylamide on intermediate filaments and microfilaments

Rabbit synovial fibroblasts respond to changes in cell shape and cytoskeletal architecture by altering specific gene expression. We have tested the ability of acrylamide, a neurotoxin that alters the distribution of intermediate filaments in cultured PtK1 cells, to induce metalloprotease expression in synovial fibroblasts. Cells treated with 2-20 mM acrylamide for 5 to 24 h underwent shape changes similar to cells treated with the tumor promoter phorbol myristate acetate. Intermediate filaments visualized with anti-vimentin antibodies did not collapse into a perinuclear cap in these rounded cells, but were still present in the extended cell processes. Unexpectedly, when actin was visualized in acrylamide-treated cells, extensive dissociation and clumping of microfilaments was observed. Concentrations of acrylamide greater than 10 mM were cytotoxic, but cells recovered completely after 24 h incubation with 5 mM acrylamide. Like other agents that alter cell shape and actin distribution in synovial fibroblasts, acrylamide also induced expression of the secreted metalloprotease collagenase. Although some recent evidence suggests that acrylamide may be able to exert its collagenase-inducing effects extracellularly, perhaps through transmembrane matrix receptors, our observation that this neurotoxin dramatically alters protein synthesis in synovial fibroblasts suggests that direct effects on cell metabolism may also play a role in acute acrylamide intoxication.