Tolloid-Like Metalloproteinases: A family of metalloproteases that are related to the DROSOPHILA protein tolloid, which is a gene product necessary for dorsal-ventral patterning in early Drosophila embryogenesis. Many members of the group may play a significant role in intercellular signaling.Matrix Metalloproteinases: A family of zinc-dependent metalloendopeptidases that is involved in the degradation of EXTRACELLULAR MATRIX components.Tissue Inhibitor of Metalloproteinases: A family of secreted protease inhibitory proteins that regulates the activity of SECRETED MATRIX METALLOENDOPEPTIDASES. They play an important role in modulating the proteolysis of EXTRACELLULAR MATRIX, most notably during tissue remodeling and inflammatory processes.Bone Morphogenetic Protein 1: A bone morphogenetic protein family member that includes an active tolloid-like metalloproteinase domain. The metalloproteinase activity of bone morphogenetic protein 1 is specific for the removal of the C-propeptide of PROCOLLAGEN and may act as a regulator of EXTRACELLULAR MATRIX deposition. Alternative splicing of MRNA for bone morphogenetic protein 1 results in the production of several PROTEIN ISOFORMS.Metalloproteases: Proteases which use a metal, normally ZINC, in the catalytic mechanism. This group of enzymes is inactivated by metal CHELATORS.Metalloendopeptidases: ENDOPEPTIDASES which use a metal such as ZINC in the catalytic mechanism.Matrix Metalloproteinase 2: A secreted endopeptidase homologous with INTERSTITIAL COLLAGENASE, but which possesses an additional fibronectin-like domain.Matrix Metalloproteinase 9: An endopeptidase that is structurally similar to MATRIX METALLOPROTEINASE 2. It degrades GELATIN types I and V; COLLAGEN TYPE IV; and COLLAGEN TYPE V.Tissue Inhibitor of Metalloproteinase-2: A member of the family of TISSUE INHIBITOR OF METALLOPROTEINASES. It is a 21-kDa nonglycosylated protein found in tissue fluid and is secreted as a complex with progelatinase A by human fibroblast and uncomplexed from alveolar macrophages. An overexpression of TIMP-2 has been shown to inhibit invasive and metastatic activity of tumor cells and decrease tumor growth in vivo.Tissue Inhibitor of Metalloproteinase-1: A member of the family of TISSUE INHIBITOR OF METALLOPROTEINASES. It is a N-glycosylated protein, molecular weight 28 kD, produced by a vast range of cell types and found in a variety of tissues and body fluids. It has been shown to suppress metastasis and inhibit tumor invasion in vitro.Matrix Metalloproteinase Inhibitors: Compounds that inhibit the enzyme activity or activation of MATRIX METALLOPROTEINASES.Matrix Metalloproteinase 3: An extracellular endopeptidase of vertebrate tissues similar to MATRIX METALLOPROTEINASE 1. It digests PROTEOGLYCAN; FIBRONECTIN; COLLAGEN types III, IV, V, and IX, and activates procollagenase. (Enzyme Nomenclature, 1992)Bone Morphogenetic Proteins: Bone-growth regulatory factors that are members of the transforming growth factor-beta superfamily of proteins. They are synthesized as large precursor molecules which are cleaved by proteolytic enzymes. The active form can consist of a dimer of two identical proteins or a heterodimer of two related bone morphogenetic proteins.Gelatinases: A class of enzymes that catalyzes the degradation of gelatin by acting on the peptide bonds. EC 3.4.24.-.Collagenases: Enzymes that catalyze the degradation of collagen by acting on the peptide bonds.Tissue Inhibitor of Metalloproteinase-3: A member of the family of tissue inhibitor of metalloproteinases. Mutations of the gene for TIMP3 PROTEIN causes Sorsby fundus dystrophy.Matrix Metalloproteinase 1: A member of the metalloproteinase family of enzymes that is principally responsible for cleaving FIBRILLAR COLLAGEN. It can degrade interstitial collagens, types I, II and III.Matrix Metalloproteinases, Membrane-Associated: Matrix metalloproteinases that are associated with the CELL MEMBRANE, either through transmembrane domains or GLYCOSYLPHOSPHATIDYLINOSITOL ANCHORS. Membrane-type matrix metalloproteinases may act within the pericellular environment to influence the process of CELL MIGRATION.Matrix Metalloproteinases, Secreted: A subclass of matrix metalloproteinases that are secreted into the pericellular space.Apraxia, Ideomotor: A form of apraxia characterized by an acquired inability to carry out a complex motor activity despite the ability to mentally formulate the action. This condition has been attributed to a disruption of connections between the dominant parietal cortex and supplementary and premotor cortical regions in both hemispheres. (From Adams et al., Principles of Neurology, 6th ed, p57)Matrix Metalloproteinase 7: The smallest member of the MATRIX METALLOPROTEINASES. It plays a role in tumor progression.Insect Hormones: Hormones secreted by insects. They influence their growth and development. Also synthetic substances that act like insect hormones.Matrix Metalloproteinase 8: A member of the MATRIX METALLOPROTEINASES that cleaves triple-helical COLLAGEN types I, II, and III.Protease Inhibitors: Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Extracellular Matrix: A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere.Intercellular Signaling Peptides and Proteins: Regulatory proteins and peptides that are signaling molecules involved in the process of PARACRINE COMMUNICATION. They are generally considered factors that are expressed by one cell and are responded to by receptors on another nearby cell. They are distinguished from HORMONES in that their actions are local rather than distal.Matrix Metalloproteinase 13: A secreted matrix metalloproteinase that plays a physiological role in the degradation of extracellular matrix found in skeletal tissues. It is synthesized as an inactive precursor that is activated by the proteolytic cleavage of its N-terminal propeptide.Body Patterning: The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.Matrix Metalloproteinase 12: A secreted matrix metalloproteinase which is highly expressed by MACROPHAGES where it may play a role in INFLAMMATION and WOUND HEALING.Matrix Metalloproteinase 10: A secreted matrix metalloproteinase that may play a role in matrix degradation during WOUND HEALING. It is expressed at high levels by KERATINOCYTES, suggesting its role in keratinocyte migration.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.TailRNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Matrix Metalloproteinase 14: A transmembrane domain-containing matrix metalloproteinase. It is synthesized as an inactive zymogen that is activated by the action of PROPROTEIN CONVERTASES such as FURIN. Matrix metalloproteinase 14 plays a direct role in the cleavage of proteins in the pericellular environment. In addition, it can function indirectly by enzymatically activating the proprotein form of MATRIX METALLOPROTEINASE 15.Drosophila Proteins: Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.Microbial Collagenase: A metalloproteinase which degrades helical regions of native collagen to small fragments. Preferred cleavage is -Gly in the sequence -Pro-Xaa-Gly-Pro-. Six forms (or 2 classes) have been isolated from Clostridium histolyticum that are immunologically cross-reactive but possess different sequences and different specificities. Other variants have been isolated from Bacillus cereus, Empedobacter collagenolyticum, Pseudomonas marinoglutinosa, and species of Vibrio and Streptomyces. EC 18.104.22.168.Gastrula: The developmental stage that follows BLASTULA or BLASTOCYST. It is characterized by the morphogenetic cell movements including invagination, ingression, and involution. Gastrulation begins with the formation of the PRIMITIVE STREAK, and ends with the formation of three GERM LAYERS, the body plan of the mature organism.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Bone Morphogenetic Protein 4: A bone morphogenetic protein that is a potent inducer of bone formation. It also functions as a regulator of MESODERM formation during EMBRYONIC DEVELOPMENT.Collagen: A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).ADAM Proteins: A family of membrane-anchored glycoproteins that contain a disintegrin and metalloprotease domain. They are responsible for the proteolytic cleavage of many transmembrane proteins and the release of their extracellular domain.Gelatin: A product formed from skin, white connective tissue, or bone COLLAGEN. It is used as a protein food adjuvant, plasma substitute, hemostatic, suspending agent in pharmaceutical preparations, and in the manufacturing of capsules and suppositories.Matrix Metalloproteinase 11: A secreted matrix metalloproteinase that is believed to play a role in EXTRACELLULAR MATRIX remodeling and cell fate determination during normal and pathological processes. Matrix metalloproteinase 11 was originally isolated in primary BREAST NEOPLASMS and may be involved in the process of tumorigenesis.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Enzyme Precursors: Physiologically inactive substances that can be converted to active enzymes.Embryo, Nonmammalian: The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.Xenopus Proteins: Proteins obtained from various species of Xenopus. Included here are proteins from the African clawed frog (XENOPUS LAEVIS). Many of these proteins have been the subject of scientific investigations in the area of MORPHOGENESIS and development.Limb Deformities, Congenital: Congenital structural deformities of the upper and lower extremities collectively or unspecified.Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Matrix Metalloproteinase 15: A transmembrane domain-containing matrix metalloproteinase that plays a role in the cleavage of proteins in the pericellular environment. It is synthesized as an inactive zymogen that is activated by the action of ENDOPEPTIDASES such as MATRIX METALLOPROTEINASE 14.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Transforming Growth Factor beta: A factor synthesized in a wide variety of tissues. It acts synergistically with TGF-alpha in inducing phenotypic transformation and can also act as a negative autocrine growth factor. TGF-beta has a potential role in embryonal development, cellular differentiation, hormone secretion, and immune function. TGF-beta is found mostly as homodimer forms of separate gene products TGF-beta1, TGF-beta2 or TGF-beta3. Heterodimers composed of TGF-beta1 and 2 (TGF-beta1.2) or of TGF-beta2 and 3 (TGF-beta2.3) have been isolated. The TGF-beta proteins are synthesized as precursor proteins.Genes, Insect: The functional hereditary units of INSECTS.Drosophila: A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.Morphogenesis: The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.Phenylmercuric Acetate: A phenyl mercury compound used mainly as a fungicide. Has also been used as a herbicide, slimicide, and bacteriocide.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Extracellular Matrix Proteins: Macromolecular organic compounds that contain carbon, hydrogen, oxygen, nitrogen, and usually, sulfur. These macromolecules (proteins) form an intricate meshwork in which cells are embedded to construct tissues. Variations in the relative types of macromolecules and their organization determine the type of extracellular matrix, each adapted to the functional requirements of the tissue. The two main classes of macromolecules that form the extracellular matrix are: glycosaminoglycans, usually linked to proteins (proteoglycans), and fibrous proteins (e.g., COLLAGEN; ELASTIN; FIBRONECTINS; and LAMININ).Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Antigens, CD147: A widely distributed cell surface transmembrane glycoprotein that stimulates the synthesis of MATRIX METALLOPROTEINASES. It is found at high levels on the surface of malignant NEOPLASMS and may play a role as a mediator of malignant cell behavior.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Matrix Metalloproteinase 16: A transmembrane domain-containing matrix metalloproteinase. It is synthesized as an inactive zymogen that is activated by the proteolytic action of PROPROTEIN CONVERTASES. Matrix metalloproteinase 16 plays a direct role in the cleavage of proteins in the pericellular environment. In addition, it can function indirectly by enzymatically activating the proprotein form of other MATRIX METALLOPROTEINASES such as the zymogen of MATRIX METALLOPROTEINASE 2.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Dipeptides: Peptides composed of two amino acid units.Sea Urchins: Somewhat flattened, globular echinoderms, having thin, brittle shells of calcareous plates. They are useful models for studying FERTILIZATION and EMBRYO DEVELOPMENT.Gene Expression Regulation, Developmental: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Neoplasm Invasiveness: Ability of neoplasms to infiltrate and actively destroy surrounding tissue.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Pepsin A: Formed from pig pepsinogen by cleavage of one peptide bond. The enzyme is a single polypeptide chain and is inhibited by methyl 2-diaazoacetamidohexanoate. It cleaves peptides preferentially at the carbonyl linkages of phenylalanine or leucine and acts as the principal digestive enzyme of gastric juice.Cell Movement: The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Doxycycline: A synthetic tetracycline derivative with similar antimicrobial activity.Procollagen N-Endopeptidase: An extracellular endopeptidase which excises a block of peptides at the amino terminal, nonhelical region of the procollagen molecule with the formation of collagen. Absence or deficiency of the enzyme causes accumulation of procollagen which results in the inherited connective tissue disorder--dermatosparaxis. EC 22.214.171.124.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Zebrafish: An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.Aggrecans: Large HYALURONAN-containing proteoglycans found in articular cartilage (CARTILAGE, ARTICULAR). They form into aggregates that provide tissues with the capacity to resist high compressive and tensile forces.Up-Regulation: A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Synovial Membrane: The inner membrane of a joint capsule surrounding a freely movable joint. It is loosely attached to the external fibrous capsule and secretes SYNOVIAL FLUID.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Cartilage, Articular: A protective layer of firm, flexible cartilage over the articulating ends of bones. It provides a smooth surface for joint movement, protecting the ends of long bones from wear at points of contact.ThiophenesPhenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Snake Venoms: Solutions or mixtures of toxic and nontoxic substances elaborated by snake (Ophidia) salivary glands for the purpose of killing prey or disabling predators and delivered by grooved or hollow fangs. They usually contain enzymes, toxins, and other factors.Culture Media, Conditioned: Culture media containing biologically active components obtained from previously cultured cells or tissues that have released into the media substances affecting certain cell functions (e.g., growth, lysis).Interleukin-1: A soluble factor produced by MONOCYTES; MACROPHAGES, and other cells which activates T-lymphocytes and potentiates their response to mitogens or antigens. Interleukin-1 is a general term refers to either of the two distinct proteins, INTERLEUKIN-1ALPHA and INTERLEUKIN-1BETA. The biological effects of IL-1 include the ability to replace macrophage requirements for T-cell activation.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Proteoglycans: Glycoproteins which have a very high polysaccharide content.Crotalid Venoms: Venoms from snakes of the subfamily Crotalinae or pit vipers, found mostly in the Americas. They include the rattlesnake, cottonmouth, fer-de-lance, bushmaster, and American copperhead. Their venoms contain nontoxic proteins, cardio-, hemo-, cyto-, and neurotoxins, and many enzymes, especially phospholipases A. Many of the toxins have been characterized.Chondrocytes: Polymorphic cells that form cartilage.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Bothrops: A genus of poisonous snakes of the VIPERIDAE family. About 50 species are known and all are found in tropical America and southern South America. Bothrops atrox is the fer-de-lance and B. jararaca is the jararaca. (Goin, Goin, and Zug, Introduction to Herpetology, 3d ed, p336)Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Disintegrins: A family of polypeptides purified from snake venoms, which contain the arginine-glycine-aspartic acid (RGD) sequence. The RGD tripeptide binds to integrin receptors and thus competitively inhibits normal integrin-ligand interactions. Disintegrins thus block adhesive functions and act as platelet aggregation inhibitors.Enzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Mice, Inbred C57BLDrosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.Crotalus: A genus of snakes of the family VIPERIDAE, one of the pit vipers, so-called from the pit hollowing out the maxillary bone, opening between the eye and the nostril. They are distinctively American serpents. Most of the 25 recognized species are found in the southwestern United States and northern Mexico. Several species are found as far north as Canada and east of the Mississippi, including southern Appalachia. They are named for the jointed rattle (Greek krotalon) at the tip of their tail. (Goin, Goin, and Zug: Introduction to Herpetology, 3d ed; Moore: Poisonous Snakes of the World, 1980, p335)ElastinEnzyme-Linked Immunosorbent Assay: An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.In Situ Hybridization: A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.Osteoarthritis: A progressive, degenerative joint disease, the most common form of arthritis, especially in older persons. The disease is thought to result not from the aging process but from biochemical changes and biomechanical stresses affecting articular cartilage. In the foreign literature it is often called osteoarthrosis deformans.Cartilage: A non-vascular form of connective tissue composed of CHONDROCYTES embedded in a matrix that includes CHONDROITIN SULFATE and various types of FIBRILLAR COLLAGEN. There are three major types: HYALINE CARTILAGE; FIBROCARTILAGE; and ELASTIC CARTILAGE.Ventricular Remodeling: The geometric and structural changes that the HEART VENTRICLES undergo, usually following MYOCARDIAL INFARCTION. It comprises expansion of the infarct and dilatation of the healthy ventricle segments. While most prevalent in the left ventricle, it can also occur in the right ventricle.Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Tumor Necrosis Factor-alpha: Serum glycoprotein produced by activated MACROPHAGES and other mammalian MONONUCLEAR LEUKOCYTES. It has necrotizing activity against tumor cell lines and increases ability to reject tumor transplants. Also known as TNF-alpha, it is only 30% homologous to TNF-beta (LYMPHOTOXIN), but they share TNF RECEPTORS.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Cell Line, Tumor: A cell line derived from cultured tumor cells.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Fibrosis: Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury.Endometrium: The mucous membrane lining of the uterine cavity that is hormonally responsive during the MENSTRUAL CYCLE and PREGNANCY. The endometrium undergoes cyclic changes that characterize MENSTRUATION. After successful FERTILIZATION, it serves to sustain the developing embryo.Laminin: Large, noncollagenous glycoprotein with antigenic properties. It is localized in the basement membrane lamina lucida and functions to bind epithelial cells to the basement membrane. Evidence suggests that the protein plays a role in tumor invasion.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.Hydroxamic Acids: A class of weak acids with the general formula R-CONHOH.Phenylalanine: An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.Blotting, Northern: Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Skin Aging: The process of aging due to changes in the structure and elasticity of the skin over time. It may be a part of physiological aging or it may be due to the effects of ultraviolet radiation, usually through exposure to sunlight.Collagen Type I: The most common form of fibrillar collagen. It is a major constituent of bone (BONE AND BONES) and SKIN and consists of a heterotrimer of two alpha1(I) and one alpha2(I) chains.Organ Culture Techniques: A technique for maintenance or growth of animal organs in vitro. It refers to three-dimensional cultures of undisaggregated tissue retaining some or all of the histological features of the tissue in vivo. (Freshney, Culture of Animal Cells, 3d ed, p1)Wound Healing: Restoration of integrity to traumatized tissue.Collagen Type IV: A non-fibrillar collagen found in the structure of BASEMENT MEMBRANE. Collagen type IV molecules assemble to form a sheet-like network which is involved in maintaining the structural integrity of basement membranes. The predominant form of the protein is comprised of two alpha1(IV) subunits and one alpha2(IV) subunit, however, at least six different alpha subunits can be incorporated into the heterotrimer.Neovascularization, Pathologic: A pathologic process consisting of the proliferation of blood vessels in abnormal tissues or in abnormal positions.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Pancreatic Elastase: A protease of broad specificity, obtained from dried pancreas. Molecular weight is approximately 25,000. The enzyme breaks down elastin, the specific protein of elastic fibers, and digests other proteins such as fibrin, hemoglobin, and albumin. EC 126.96.36.199.Inflammation: A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.Disease Progression: The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.Neoplasm Metastasis: The transfer of a neoplasm from one organ or part of the body to another remote from the primary site.Down-Regulation: A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Urokinase-Type Plasminogen Activator: A proteolytic enzyme that converts PLASMINOGEN to FIBRINOLYSIN where the preferential cleavage is between ARGININE and VALINE. It was isolated originally from human URINE, but is found in most tissues of most VERTEBRATES.Basement Membrane: A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.Arthritis, Rheumatoid: A chronic systemic disease, primarily of the joints, marked by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures. Etiology is unknown, but autoimmune mechanisms have been implicated.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Cathepsins: A group of lysosomal proteinases or endopeptidases found in aqueous extracts of a variety of animal tissues. They function optimally within an acidic pH range. The cathepsins occur as a variety of enzyme subtypes including SERINE PROTEASES; ASPARTIC PROTEINASES; and CYSTEINE PROTEASES.Fibrinolysin: A product of the lysis of plasminogen (profibrinolysin) by PLASMINOGEN activators. It is composed of two polypeptide chains, light (B) and heavy (A), with a molecular weight of 75,000. It is the major proteolytic enzyme involved in blood clot retraction or the lysis of fibrin and quickly inactivated by antiplasmins.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Macrophages: The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.HemopexinSynovial Fluid: The clear, viscous fluid secreted by the SYNOVIAL MEMBRANE. It contains mucin, albumin, fat, and mineral salts and serves to lubricate joints.PhenanthrolinesFibronectins: Glycoproteins found on the surfaces of cells, particularly in fibrillar structures. The proteins are lost or reduced when these cells undergo viral or chemical transformation. They are highly susceptible to proteolysis and are substrates for activated blood coagulation factor VIII. The forms present in plasma are called cold-insoluble globulins.Stromal Cells: Connective tissue cells of an organ found in the loose connective tissue. These are most often associated with the uterine mucosa and the ovary as well as the hematopoietic system and elsewhere.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Fibrillar Collagens: A family of structurally related collagens that form the characteristic collagen fibril bundles seen in CONNECTIVE TISSUE.Neovascularization, Physiologic: The development of new BLOOD VESSELS during the restoration of BLOOD CIRCULATION during the healing process.Inflammation Mediators: The endogenous compounds that mediate inflammation (AUTACOIDS) and related exogenous compounds including the synthetic prostaglandins (PROSTAGLANDINS, SYNTHETIC).Blood-Brain Barrier: Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.Corneal Ulcer: Loss of epithelial tissue from the surface of the cornea due to progressive erosion and necrosis of the tissue; usually caused by bacterial, fungal, or viral infection.