Matrix metalloproteinases and tissue inhibitor of metalloproteinase-2 in fetal rabbit lung

Yuh Fukuda1, Masamichi Ishizaki1, Yasunori Okada2, Motoharu Seiki3, and Nobuaki Yamanaka1

1 Department of Pathology, Nippon Medical School, Tokyo 113-0022; 2 Department of Pathology, Keio University School of Medicine, Tokyo 160-0016; and 3 Department of Cancer Cell Research, Institute of Medical Science, University of Tokyo, Tokyo 108-0071, Japan


    ABSTRACT
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

Cell-extracellular matrix interaction and extracellular matrix remodeling are known to be important in fetal lung development. We investigated the localization of matrix metalloproteinases (MMPs) in fetal rabbit lungs. Immunohistochemistry for type IV collagen, MMP-1, MMP-2, MMP-9, membrane type (MT) 1 MMP, and tissue inhibitor of metalloproteinase (TIMP)-2 and in situ hybridization for MMP-9 mRNA were performed. Gelatin zymography and Western blotting for MT1-MMP in lung tissue homogenates were also studied. MMP-1 and MT1-MMP were detected in epithelial cells, and MMP-2 and TIMP-2 were detected in epithelial cells and some mesenchymal cells in each stage. MMP-9 was found in epithelial cells mainly in the late stage. Gelatin zymography revealed that the ratio of active MMP-2 to latent MMP-2 increased dramatically during the course of development. MT1-MMP was detected in tissue homogenates, especially predominant in the late stage. These findings suggest that MMPs and their inhibitors may contribute to the formation of airways and alveoli in fetal lung development and that activated MMP-2 of alveolar epithelial cells may function to provide an extremely wide alveolar surface.

formation of alveoli; type IV collagen; membrane type 1 matrix metalloproteinase; gelatin zymography


    INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

THE FETAL DEVELOPMENT OF THE LUNG has been divided into three stages: glandular, canalicular, and alveolar (10). One of the important processes in fetal lung development is generation of a large respiratory surface, the interface between type I alveolar epithelial cells and capillary endothelial cells. Epithelial buds form a basic airway branching structure in the glandular stage, and endothelial cells form a fine meshwork structure, whereas alveolar epithelial cells differentiate in the canalicular and alveolar stages. These changes are associated with the formation and remodeling of the extracellular matrix (ECM). Large areas of the surfaces of both alveolar epithelial cells and capillary endothelial cells abut a single basement membrane in the alveoli in the canalicular and alveolar stages. Formation of the basement membrane and interstitial ECM is of special interest in fetal lung development because of the importance of these elements in the determination of the mechanical and functional properties of lung tissue (10, 12, 24). Moreover, matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are known to regulate ECM remodeling and thus are important in the morphogenesis of all the fetal organs (2, 4, 5, 11, 15-17, 21, 22, 27, 29). It is known that MMP-2 is activated only by membrane-type (MT) MMPs (15, 26). In this context, we investigated the distribution and expression of MMP-1 (interstitial collagenase), MMP-2 (gelatinase A), MMP-9 (gelatinase B), MT1-MMP, and TIMP-2 in fetal rabbit lungs. For this purpose, we used light-microscopic immunohistochemistry, in situ hybridization, Western blotting, and gelatin zymography, the latter of which enabled us to detect the active forms of the MMPs in lung specimens.


    MATERIALS AND METHODS
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

The lungs of prenatal and postnatal albino rabbits (Saitama Experimental Animal Supply, Saitama, Japan) were used in this study. The prenatal ages of these animals (18 days, n = 4; 23 days, n = 4; 26 days, n = 4; 29 days, n = 4) were determined from the dates of mating. Rabbits 1 day after birth (n = 4) were also used. The age of full-term rabbits in the laboratory is 30 days after conception. Fetal rabbits were obtained by cesarean section under anesthesia with pentobarbital sodium. Fetal and postnatal animals were deeply anesthetized, and the lungs were removed. The experimental procedures were approved by the Animal Experimental Ethical Review Committee of Nippon Medical School (Tokyo, Japan).

Light-microscopic study For light-microscopic study, tissue blocks were fixed in a solution of 4% paraformaldehyde in 0.1 M phosphate buffer, pH 7.4, at 4°C overnight. The lungs of postnatal rabbits were perfused via the trachea at a pressure of 20 cmH2O with the same fixative. They were then dehydrated and embedded in paraffin. Sections were stained with hematoxylin and eosin, elastica Masson-Goldner, Alcian blue-periodic acid-Schiff, and Victoria blue.

Antibodies. Primary antibodies used for the immunohistochemical studies included goat anti-human type IV collagen antibody (Southern Biotechnology Associates), mouse anti-human MMP-1 antibody (clone 41-1E5) (30), mouse anti-human MMP-2 antibody (clone 42-5D11) (8), mouse anti-human MMP-9 antibody (clone 56-2A4) (19), mouse anti-human MT1-MMP antibody (clone 114-1F2) (15), and mouse anti-human TIMP-2 antibody (clone 68-6H4; all from Fuji Chemical Industries, Takaoka, Japan) (9). The antibodies against the MMPs and TIMP-2 were previously characterized by methods including Western blotting and were used for immunostaining (8, 9, 19, 20, 28, 30). All the antibodies against the MMPs recognize both the latent and active forms of their respective MMPs (8, 19, 30). The antibodies against MMP-1, MMP-2, MMP-9, and TIMP-2 have been confirmed to cross-react with rabbit tissues by Western blotting (28). In this study, we confirmed the cross-reactivity of the antibody against MT1-MMP with rabbit tissue by Western blotting (Fig. 5). As the secondary antibodies, biotin-labeled rabbit anti-goat IgG antibody, biotin-labeled goat anti-mouse IgG antibody, and horseradish peroxidase-labeled goat anti-mouse lgG antibody (all from Dakopatts, Glostrup, Denmark) were used.

Light-microscopic immunoperoxidase method. The immunoperoxidase method was used for the detection of type IV collagen, MMPs, and TIMP-2. The paraffin sections were treated with 0.3% H2O2 in methanol for blocking of endogenous peroxidase activity and with 8 M guanidine in 0.1 M Tris·HCl, pH 7.6, overnight for unmasking of the antigenic sites (6, 28). After treatment with normal rabbit or goat serum, they were incubated with an appropriate dilution of one of the primary antibodies. The tissue sections were then incubated with biotinylated goat anti-mouse IgG antibody, treated with a solution of streptavidin-biotin-peroxidase complex (Dakopatts), reacted with a solution of 3,3'-diaminobenzidine and H2O2, and counterstained with Mayer's hematoxylin.

In situ hybridization for MMP-9. The lung tissue blocks from 29-day-gestation rabbits were fixed in a solution of 4% paraformaldehyde in 0.1 M phosphate buffer and frozen. Frozen sections were cut, mounted on 3-aminopropyltriethoxysilane-coated slides, air-dried, and then subjected to hybridization. RNA probes for in situ hybridization were labeled with digoxigenin-11-UTP. A 1,229-bp Pst I-EcoR I fragment of the MMP-9 cDNA (25) was subcloned into the transcription vector pBluescript II (Stratagene, La Jolla, CA). An antisense strand (positive probe) was obtained by linearization with Xba I and transcription with T7 RNA polymerase (Promega, Madison, WI). A sense strand (negative probe) was obtained by linearization with EcoRI and transcription with T3 RNA polymerase (Promega). The probes were hydrolyzed to ~200 bp in length. Hybridization was performed with 25 µl of hybridization buffer containing 100 ng RNA probe/slide and incubation at 42°C overnight. The slides were washed with 0.5× saline-sodium citrate (SSC) and with a solution containing 50% formamide, 0.15 M NaCl, 5 mM Tris·HCl (pH 7.4), and 0.5 mM EDTA at room temperature. They were then washed with 0.5× SSC and 0.2× SSC at 55°C and with 0.2× SSC at room temperature. The immunologic detection of the hybridization probe was carried out as described in the instructions supplied with the Boehringer Mannheim digoxigenin-nucleic acid detection kit (Boehringer Mannheim, Mannheim, Germany). The slides were incubated with diluted alkaline phosphatase-labeled anti-digoxigenin antibody, and the reactions were visualized with a solution containing nitro blue tetrazolium salt and 5-bromo-4-chloro-3-indoyl phosphate toluidine salt.

Gelatin zymography. Unfixed frozen lung specimens were prepared from animals of 23, 26, and 29 days gestational age and 1 day after birth (n = 3). The lung samples were homogenized in 2.5% sodium dodecyl sulfate (SDS) without reducing agent. Gelatin-degrading activity was examined by electrophoresis in 8% polyacrylamide gels containing gelatin (2 mg/ml; Sigma, St. Louis, MO) according to the method of Hibbs et al. (13). Immediately after homogenization, the homogenate of 1 or 0.2 mg of lung tissue was applied to each lane of the gels. After electrophoresis and removal of SDS from the gels, they were incubated for 20 h at 37°C in 50 mM Tris·HCl, pH 7.5, 0.15 M NaCl, 10 mM CaCl2, and 0.02% NaN3 and stained with Coomassie brilliant blue R250. Densitometric analysis of the gels was performed with a Power Macintosh 8500/120 computer (Apple Japan, Tokyo, Japan) with a high-resolution scanner and NIH Image software (version 1.61, National Institutes of Health, Bethesda, MD).

Western blot analysis for MT1-MMP. Unfixed frozen lung tissue samples obtained from the animals of 23, 26, and 29 days gestational age and 1 day after birth (n = 1) were homogenized in lysis buffer (150 mmol/l of NaCl, 1% Nonidet P-40, 1% sodium deoxycholate, 0.1% SDS, 50 mmol/l of NaF, 10 µg/ml aprotinin, 10 µg/ml of leupeptin, 1 mmol/l of Na3VO4, 1 mmol/l of phenylmethylsulfonyl fluoride, and 20 mmol/l of Tris·HCl, pH 7.4). After centrifugation at 15,000 g for 30 min at 4°C, the supernatant was used in this study. The samples containing 2.5 g of protein were separated on 10% acrylamide gel by SDS-PAGE. After electrophoresis, the separated proteins were transferred to a Hybond-P nitrocellulose membrane (Amersham) and probed with anti-MT1-MMP antibody. Bound antibody was detected with horseradish peroxidase-conjugated anti-mouse lgG antibody (1:500) with the enhanced chemiluminescence detection system. Densitometric analysis of the gels was performed with NIH Image software.


    RESULTS
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

Eighteen days of gestation: glandular stage. The light-microscopic study of this stage revealed branching glands composed of columnar epithelium and loose stroma. The following distinct zones were identified: a primitive bronchiolar zone and the tip (10). The primitive bronchiolar zones were covered with smooth muscle cells.

The immunohistochemical study showed that the reaction for type IV collagen was localized in the basement membranes of epithelial cells, endothelial cells, and smooth muscle cells but that the basement membranes of the tips of the glands were thin (Fig. 1A). MMP-1 immunoreactivity was located in the epithelial cells (Fig. 1B). Only slight MMP-9 immunoreactivity was detected in the epithelial cells (Fig. 1C). MMP-2 immunoreactivity was found in the epithelial cells and some mesenchymal cells (Fig. 1D). MT1-MMP immunoreactivity was found in the epithelial cells (Fig. 1E). TIMP-2 immunoreactivity was detected in the epithelial cells, endothelial cells, mesothelial cells, and mesenchymal cells (Fig. 1F).


View larger version (93K):
[in this window]
[in a new window]
 
Fig. 1.   Eighteen days of gestation: glandular stage. A: type IV collagen is present in walls of the capillaries and around the glands. The basement membrane around the stalk of the glands is thick, but that around the tip (T) of the gland is thin. B: reaction for matrix metalloproteinase (MMP)-1 is located in the epithelial cells. C: only a slight reaction for MMP-9 is found in the epithelial cells. D: MMP-2 is slightly positive in the epithelial cells and some mesenchymal cells. E: membrane type 1 (MT1) MMP is detected in the epithelial cells. F: tissue inhibitor of metalloproteinase (TIMP)-2 is detected in the epithelial cells, endothelial cells, and mesenchymal cells. Immunoperoxidase method; bars, 40 µm.

Twenty-three days of gestation: canalicular stage. The glands were more branched and composed of shorter cuboidal cells than those in the previous stage. The primitive alveolar zone was identified between the primitive bronchiolar zone and the tip in this stage. The stroma of alveolar walls was thinner than in the previous stages and the tips of alveolar septa were recognized. Type IV collagen was detected in the epithelial and endothelial basement membranes (Fig. 2A). Around the primitive alveolar zones, type IV collagen-positive basement membranes, including the areas of bifurcation, were thick. The basement membranes of the tips of the glands were thin, similar to the previous stage. MMP-1 immunoreactivity was detected mainly in the epithelial cells (Fig. 2B). A slight immune reaction for MMP-9 was found in the epithelial cells (Fig. 2C). MMP-2 was detected in the epithelial cells and some mesenchymal cells (Fig. 2D). MT1-MMP was found in the epithelial cells of the primitive alveolar zone (Fig. 2E). The epithelial cells of the primitive bronchiolar zone were less positive for MT1-MMP. TIMP-2 was detected in the epithelial cells and some mesenchymal cells (Fig. 2F).


View larger version (84K):
[in this window]
[in a new window]
 
Fig. 2.   Twenty-three days of gestation: canalicular stage. A: reactions for type IV collagen are found in basement membranes of epithelial cells and endothelial cells. Around the primitive alveolar zone, basement membrane is thick, similar to the previous stage. B: MMP-1 is mainly detected in the epithelial cells of the glands. C: MMP-9 is slightly positive in the epithelial cells. D: MMP-2 is found in the epithelial cells and some mesenchymal cells. E: reaction for MT1-MMP is detected in the epithelial cells including the tips of the gland but is less in the epithelial cells of primitive bronchioles (B). F: TIMP-2 is detected in the epithelial cells and some mesenchymal cells. Immunoperoxidase method; bars, 40 µm.

Twenty-nine days of gestation: alveolar stage. The basic structures of the bronchi, bronchioles, and alveoli were complete in this stage. The structures of the gland tips were only occasionally observed at the periphery of the lobules. The stroma was thinner than in the previous stages, and the alveolar epithelial and capillary endothelial basement membranes were thin and frequently fused (Fig. 3A). MMP-1 immunoreactivity was detected in type II alveolar epithelial, bronchial, and bronchiolar epithelial cells (Fig. 3B). MMP-9 was detected in type II alveolar epithelial, bronchial, and bronchiolar epithelial cells (Fig. 3C) and in macrophages. MMP-2 was detected in bronchial and bronchiolar epithelial cells, type II alveolar epithelial cells, vascular endothelial cells, and some mesenchymal cells (Fig. 3, D and E). MT1-MMP was found in epithelial cells, especially in type II and some thinning type I alveolar epithelial cells (Fig. 3F). TIMP-2 was detected in the epithelial cells of airways and alveoli and some mesenchymal cells (Fig. 3G).


View larger version (110K):
[in this window]
[in a new window]
 
Fig. 3.   Twenty-nine days of gestation: alveolar stage. A: type IV collagen is distributed in the basement membranes. B: MMP-1 is found in the bronchial and type II alveolar epithelial cells (arrows). C: MMP-9 is positive in the bronchial and type II epithelial cells (arrows). D: MMP-2 is detected in the bronchial and type II epithelial cells (arrow). E: high magnification shows the reaction for MMP-2 in type II epithelial cells (arrow) and some vascular endothelial cells (arrowheads). F: MT1-MMP is detected in type II and some thinning alveolar epithelial cells (arrows). G: TIMP-2 is detected in the epithelial cells of airways and type II epithelial cells (arrow). H: in situ hybridization with an antisense probe of MMP-9 mRNA shows the positive reaction in bronchial and type II epithelial cells (arrows). I: in situ hybridization with a sense probe of MMP-9 mRNA as negative control shows no reaction. A-G, immunoperoxidase method; H and I, in situ hybridization; bars, 40 µm.

In situ hybridization with an antisense probe of MMP-9 mRNA revealed the presence of MMP-9 mRNA in bronchial epithelial cells, type II alveolar epithelial cells, and macrophages of lung tissues of 29 days gestation (Fig. 3H). In situ hybridization using a sense probe of MMP-9 mRNA showed no reaction (Fig. 3I).

One day after birth. The alveoli were normally open, and type II and type I alveolar epithelial cells were located on the thin alveolar walls. The reactions for type IV collagen, MMP-1, MMP-2, MMP-9, MT1-MMP, and TIMP-2 were similar to those at 29 days of gestation.

Detection of gelatinolytic activity. By gelatin zymography, gelatinolytic activities with different molecular masses were detected in the tissue homogenates (Fig. 4). Of them, the activities of ~68 and 62 kDa were predominant. They corresponded to the latent and active forms of MMP-2, respectively (Fig. 4B). The ratio of the active MMP-2 to the latent MMP-2 in the 23-day-gestation lung homogenate samples seemed to be minimal compared with those in the other stages, and this ratio seemed to increase dramatically during lung development (Fig. 4B). Densitometric analysis showed that the ratio 1 day after birth was significantly larger than those in other stages (P < 0.01) and that the ratio at 29 days was significantly larger than that at 23 days (P < 0.05; Fig. 4C). Gelatinolytic activity of ~92 kDa (Fig. 4A), corresponding to latent MMP-9, was also detected in the lung homogenate samples later than 26 days of gestation. The levels of the gelatinolytic activity of MMP-9 seemed to increase during lung development, but they were not significantly different.


View larger version (39K):
[in this window]
[in a new window]
 
Fig. 4.   Gelatin zymography. One (A) or two-tenths (B) mg of lung tissue was applied to each lane of gels. Gelatinolytic activities with various molecular masses were detected in the tissue extracts. Of them, the gelatinolytic activities of ~68 and 62 kDa were predominant (B). They correspond to the latent (laMMP-2) and active (acMMP-2) forms of MMP-2, respectively. Gelatinolytic activity of ~92 kDa, corresponding to latent MMP-9 (laMMP-9), was also detected in the later than 26-day-gestation lungs (A). F23d, F26d, and F29d, 23, 26, and 29 days of gestation, respectively. C: densitometric analysis of B shows that the ratio of active to latent forms of MMP-2 1 day after birth was significantly larger than the ratios in other stages (** P < 0.01) and that the ratio at 29 days was significantly larger than that at 23 days (* P < 0.05).

Western blot analysis for MT1-MMP. Chemiluminescent bands corresponding to MT1-MMP were detected in lung tissue homogenates of animals in each stage (Fig. 5A). The levels of MT1-MMP seemed to increase during lung development, and this was confirmed by this densitometric analysis (Fig. 5B).


View larger version (30K):
[in this window]
[in a new window]
 
Fig. 5.   A: Western blot analysis of MT1-MMP. Chemiluminescent bands corresponding to MT1-MMP were detected in tissue homogenates of animals in each stage. B: densitometric analysis of A shows that the amount of MT1-MMP seemed to increase during lung development.


    DISCUSSION
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

In this study, we demonstrated the correlation between the morphological changes and the distribution of MMPs and TIMP-2 in developing lungs. In the early stages of rabbit lung development, MMP-1, MMP-2, MMP-9, and MT1-MMP are distributed in epithelial cells, and they may be involved in the formation of the basic structure of an airway. In the late stage and postnatal lungs, MMP-2 may be greatly activated by MT1-MMP localized in the alveolar epithelial cells. It is suggested that activated MMP-2 of alveolar epithelial cells contributes to provide an extremely wide alveolar surface. MMP-9 detected in the bronchial epithelial cells and type II alveolar epithelial cells may be involved in the late stage of lung development.

MMPs in branching morphogenesis and type II cells. MMP-1, MMP-2, MMP-9, and MT1-MMP immunoreactivities were detected in glandular epithelial cells in the glandular stage, in cuboidal epithelial cells in the canalicular stage, and in type II alveolar epithelial cells in the alveolar stage and in postnatal lungs. In a previous electron-microscopic study (10), epithelial basement membranes and collagen fibrils were found to be densely distributed around the epithelia except for the tip of the glandular structures in the developing fetal sheep lung. In the later stages, basement membranes and interstitial collagens were more widely distributed in the bronchial and alveolar walls (12). Collagen, collagenases, and their inhibitors have been reported to be important in branching morphogenesis in fetal salivary glands (11, 17). MMP-1 mRNA expression has been reported to be increased during fetal lung development (23). MMP-1 is an interstitial collagenase, and type I and type III collagens are good substrates for it (3). MMP-2 and MMP-9 are known to be type IV collagenases and degrade basement membrane components and elastin. Gelatinolytic activities corresponding to those of MMP-9 have been detected in fetal rat lung in both epithelial cells and fibroblasts (22). MT1-MMP not only activates latent MMP-2 but also degrades interstitial collagens and other ECMs (7, 18). In this study, we demonstrated that the level of MMP-2 and MMP-9 gelatinolytic activities seemed to increase during lung development. MMP-1, MMP-2, MMP-9, and MT1-MMP may contribute to the branching morphogenesis in developing rabbit lungs. Many other MMPs and other matrix proteinases that were not examined in this study may also be involved in fetal lung development. Further studies are needed to clarify the complexities in the process of organ morphogenesis.

MMP-2 activation in the formation of alveoli. During fetal lung development, alveolar respiratory surfaces consisting of the interfaces of type I alveolar epithelial cells and alveolar capillary endothelial cells increase dramatically in area (10). Wavy and thickened epithelial basement membranes are characteristic of fetal lungs and surround the glands in the glandular stage (10). The thinning of alveolar epithelial cells, which represents the differentiation of type I alveolar epithelial cells from type II cells, is coordinated with the thinning of the epithelial basement membranes (1, 10). The alveolar capillaries form a meshlike network surrounding the alveolar sac in the alveolar stage (10). MMP-2 is known to be expressed in various fetal organs including the lung, and MMP-2 is physically activated during fetal lung development (2, 15, 16, 21, 22). In this study, we clearly showed the presence of MT1-MMP in type II and thinning type I alveolar epithelial cells. Latent MMP-2 activation is thought to be mediated by MT-MMPs that are expressed on the cell surface (16, 26). The activation ratio of MMP-2 increased dramatically during the lung development. The results of this study suggest that MMP-2 and MT1-MMP of alveolar epithelial cells may be involved in the thinning of alveolar epithelial basement membrane and the acquisition of large respiratory interfaces of alveoli in the lung development. Although it is reported that mice with a targeted deletion of MMP-2 appear to have normal lungs (14), some unknown matrix proteinases may compensate for MMP-2 in the process of fetal development in these mice.

TIMP-2 was codistributed with various types of MMPs in the epithelial cells and some mesenchymal cells in each stage of the developing rabbit lungs. Although TIMP-2 inhibits MMP-1, MMP-2, MMP-9, and MT1-MMP at high concentrations (9), TIMP-2 is also suggested to be involved in cellular activation of latent MMP-2 at low concentrations, in association with MT-MMPs on cell surfaces in embryogenesis (15). The mechanism of regulation and interaction of MMPs and TIMPs in vivo are clearly complex and remain to be clarified.


    ACKNOWLEDGEMENTS

We thank Arimi Ishikawa and Kyoko Wakamatsu (Department of Pathology, Nippon Medical School, Tokyo, Japan) for technical assistance.


    FOOTNOTES

This work was supported by a grant-in-aid for interstitial lung diseases from the Ministry of Health and Welfare, Japan.

Address for reprint requests and other correspondence: Y. Fukuda, Dept. of Pathology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-0022, Japan (E-mail: fukuda{at}nms.ac.jp).

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Received 10 February 1999; accepted in final form 28 March 2000.


    REFERENCES
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

1.   Adamson, IYR, and Bowden DH. Derivation of type 1 epithelium from type 2 cells in the developing rat lung. Lab Invest 32: 736-745, 1975[ISI][Medline].

2.   Arden, MG, Spearman MA, and Adamson IYR Degradation of type IV collagen during the development of fetal rat lung. Am J Respir Cell Mol Biol 9: 99-105, 1993[ISI][Medline].

3.   Berman, MB. Collagenase and corneal ulceration. In: Collagenase on Normal and Pathological Connective Tissues, edited by Woolley DW, and Evanson JM.. Chichester, UK: Wiley, 1980, p. 141-174.

4.   Canete-Soler, R, Gui YH, Linask KK, and Muschel RJ. Developmental expression of MMP-9 (gelatinase B) mRNA in mouse embryos. Dev Dyn 204: 30-40, 1995[ISI][Medline].

5.   Casasco, A, Casasco M, Reguzzoni M, Calligaro A, Tateo S, Stetler-Stevenson WG, and Liotta LA. Occurrence and distribution of matrix metalloproteinase-2-immunoreactivity in human embryonic tissues. Eur J Histochem 39: 31-38, 1995[ISI][Medline].

6.   Costa, PP, Jacobsson B, Collins VP, and Biberfeld P. Unmasking antigen determinants in amyloid. J Histochem Cytochem 34: 1683-1685, 1986[Abstract].

7.   D'Ortho, MP, Will H, Atkinson S, Butler G, Messent A, Gavrilovic J, Smith B, Timple R, Zardi L, and Murphy G. Membrane-type matrix metalloproteinases 1 and 2 exhibit broad-spectrum proteolytic capacities compatible to many matrix metalloproteinases. Eur J Biochem 250: 751-767, 1997[Abstract].

8.   Fujimoto, N, Mouri N, Iwata K, Ohuchi E, Okada Y, and Hayakawa T. A one-step sandwich enzyme immunoassay for human matrix metalloproteinase 2 (72-kDa gelatinase/type IV collagenase) using monoclonal antibodies. Clin Chim Acta 221: 91-103, 1993[ISI][Medline].

9.   Fujimoto, N, Zhang J, Iwata K, Shinya T, Okada Y, and Hayakawa T. A one-step sandwich immunoassay for tissue inhibitor of metalloproteinases-2 using monoclonal antibodies. Clin Chim Acta 220: 31-45, 1993[ISI][Medline].

10.   Fukuda, Y, Ferrans VJ, and Crystal RG. The development of alveolar septa in fetal sheep lung: ultrastructural and immunohistochemical study. Am J Anat 167: 405-439, 1983[ISI][Medline].

11.   Fukuda, Y, Masuda Y, Kishi J, Hashimoto Y, Hayakawa T, Nogawa H, and Nakanishi Y. The role of interstitial collagens in cleft formation of mouse embryonic submandibular gland during initial branching. Development 103: 259-267, 1988[Abstract].

12.   Heine, UI, Munoz EF, Flanders KC, Roberts AB, and Sporn MB. Colocalization of TGF-beta 1 and collagen I and III, fibronectin and glycosaminoglycans during lung branching morphogenesis. Development 109: 29-36, 1990[Abstract].

13.   Hibbs, MS, Hasty KA, Seyer JM, Kang AH, and Moinardi CL. Biochemical and immunological characterization of the secreted forms of human neutrophil gelatinase. J Biol Chem 260: 2493-2500, 1985[Abstract].

14.   Itoh, T, Ikeda T, Gomi H, Nakao S, Suzuki T, and Itohara S. Unaltered secretion of beta-amyloid precursor protein in gelatinase A (matrix metalloproteinase 2) deficient mice. J Biol Chem 272: 22389-22392, 1997[Abstract/Free Full Text].

15.   Kinoh, H, Sato H, Tsunezuka Y, Takino T, Kawashima A, Okada Y, and Seiki M. MT-MMP, the cell surface activator of pro-MMP-2 (pro-gelatinase), is expressed with its substrate in mouse tissue during embryogenesis. J Cell Sci 109: 953-959, 1996[Abstract/Free Full Text].

16.   Malicdem, M, Taylor W, Goerke M, and Devaskar U. Ontogeny of rat lung type IV collagenase mRNA expression and collagenolytic activity during the perinatal period. Biol Neonate 64: 376-381, 1993[ISI][Medline].

17.   Nakanishi, Y, Sugiura F, Kishi J, and Hayakawa T. Collagenase inhibitor stimulates cleft formation during early morphogenesis of mouse salivary gland. Dev Biol 113: 201-206, 1986[ISI][Medline].

18.   Ofuchi, E, Imai K, Fujii Y, Sato H, Seiki M, and Okada Y. Membrane type 1 matrix metalloproteinase digest interstitial collagens and other extracellular matrix macromolecules. J Biol Chem 277: 2446-2451, 1997.

19.   Okada, Y, Gonoji Y, Naka K, Tomita K, Nakanishi I, Iwata K, Yamashita K, and Hayakawa T. Matrix metalloproteinase 9 (92-kDa gelatinase/type IV collagenase) from HT 1080 human fibrosarcoma cells. J Biol Chem 267: 21712-21719, 1992[Abstract/Free Full Text].

20.   Okada, Y, Morodomi T, Enghild JJ, Suzuku K, Yasui A, Nakanishi I, Salveson G, and Nagase H. Matrix metalloproteinase 2 from human rheumatoid synovial fibroblasts. Eur J Biochem 194: 721-730, 1990[Abstract].

21.   Reponen, P, Sahlberg C, Huhtala P, Hurskainen T, Thesleff I, and Tryggvason K. Molecular cloning of murine 72-kDa type IV collagenase and its expression during mouse development. J Biol Chem 267: 7856-7862, 1992[Abstract/Free Full Text].

22.   Rolland, G, Xu J, Dupret JM, and Post M. Expression and characterization of type IV collagenases in rat lung cells during development. Exp Cell Res 218: 346-350, 1995[ISI][Medline].

23.   Rolland, G, Xu J, Tanswell AK, and Post M. Ontogeny of extracellular matrix gene expression by rat lung cells at late fetal gestation. Biol Neonate 73: 112-120, 1998[ISI][Medline].

24.   Roman, J, and McDonald JA. Expression of fibronectin, the integrin alpha 5, and alpha-smooth muscle actin in heart and lung development. Am J Respir Cell Mol Biol 6: 472-480, 1992[ISI][Medline].

25.   Sato, H, Kida Y, Endo Y, Mai M, Sasaki T, and Seiki M. Expression of genes encoding type IV collagen-degrading metalloproteinases and tissue inhibitor of metalloproteinases in various human tumor cells. Oncogene 7: 77-83, 1992[ISI][Medline].

26.   Sato, H, Takino T, Okada Y, Cao J, Shinagawa A, Yamamoto E, and Seiki M. A matrix metalloproteinase expressed on the surface of invasive tumour cells. Nature 370: 61-65, 1994[ISI][Medline].

27.   Sutherland, RS, Baskin LS, Elfman F, Hayward SW, and Cunha GR. The role of type IV collagenases in rat bladder development and obstruction. Pediatr Res 41: 430-434, 1997[Abstract].

28.   Tatsuguchi, A, Fukuda Y, Ishizaki M, and Yamanaka N. Localization of matrix metalloproteinases and tissue inhibitor of metalloproteinases-2 in normal human and rabbit stomachs. Digestion 60: 246-254, 1999[ISI][Medline].

29.   Terada, T, Okada Y, and Nakanuma Y. Expression of matrix proteinases during human intrahepatic bile duct development. A possible role in biliary cell migration. Am J Pathol 147: 1207-1213, 1995[Abstract].

30.   Zhang, J, Fujimoto N, Iwata K, Sakai T, Okada Y, and Hayakawa T. A one-step sandwich enzyme immunoassay for human matrix metalloproteinase 1 (interstitial collagenase) using monoclonal antibodies. Clin Chim Acta 219: 1-14, 1993[ISI][Medline].


Am J Physiol Lung Cell Mol Physiol 279(3):L555-L561
1040-0605/00 $5.00 Copyright © 2000 the American Physiological Society