Expression of Matrix Metalloproteinases 2, 7 and 9, and Their Tissue Inhibitors 1 and 2, in Developing Rabbit Tracheae

Abstract

Background: Structural changes in the developing conducting airway impact the rigidity of the airway, altering the airway’s ability to sustain its shape during ventilation. The developmental changes in airway compliance oppose the changes in compliance of the developing lung; thus the expression profiles of matrix modeling proteins likely are also opposite in these developing organs. Objectives: To determine the profiles of matrix metalloproteinases (MMPs) -2, -7, and -9 and tissue inhibitors (TIMPs) -1 and -2 in the developing trachea and test the hypothesis these profiles would contrast those previously reported for the lung. Methods: Rabbits tracheae were harvested at 21 days of gestation, 3 and 17 days postgestation and at adulthood. Tissue homogenates were analyzed by substrate zymography for the activity of MMPs, and reverse zymography for TIMPs. Immunostainings on neonatal lamb tracheal rings were used to localize MMP-2 and 9. Results: Analysis revealed an age-dependent decrease in total MMP-2 quantity and the ratio of active to latent forms. TIMP-2 shows a time-dependent increase throughout airway development. Total MMP-9 and TIMP-1 quantities were unchanged across these ages, although MMP-9 protein was found predominantly in its latent form during development and predominantly in its active form during adulthood. Respiratory epithelial cells reacted positive for both MMP-2 and 9 and trachealis muscle fibers were positive for MMP-2. No MMP-7 expression was identified in the rabbit airway. Conclusions: The opposing developmental patterns in MMP-2 expression between the airway and lung lead to speculation regarding the role of MMP-2 activity on changes in organ compliance.

KL4-Surfactant (Lucinactant) Protects Human Airway Epithelium from Hyperoxia

“…Loading buffer was added to ASF samples, and equal volumes of each sample were loaded into gels for electrophoresis. Protein was separated in 10% acrylamide gels containing 1 mg/mL gelatin (MMP-2 and MMP-9; Sigma Chemical Co., St. Louis, MO) or casein substrate (MMP-7; Sigma Chemical Co.) as previously described (24). After electrophoresis, SDS was eluted by washing the gels in 2.5% Triton-X-100.…”

Effects of recombinant Clara cell secretory protein (rhCC10) on inflammatory-related matrix metalloproteinase activity in a preterm lamb model of neonatal respiratory distress

“…Substrate zymography and reverse zymography were performed as previously described (24) to quantify the relative activity of MMPs and TIMPs, respectively. Equal amounts of total protein from tissue homogenates were electrophoresed in acrylamide gels containing gelatin or casein substrate (zymography; Sigma, St. Louis, MO) or gelatin and recombinant human MMP-2 (reverse zymography; Oncogene Research Products, Cambridge, MA).…”

IL-13, Asthma and Glycosylation in Airway Epithelial Repair

“…In vivo studies have shown MMPs play a direct role in the development of allergic airway inflammation [114] and hyperresponsiveness [115][116][117]. Inflammatory cells, particularly neutrophils and alveolar macrophages, were thought to be the major source of increased proteinases in asthma and other inflammatory lung diseases [118,119], however several groups have demonstrated structural cells of the lung including the epithelium, also synthesize MMPs and their endogenous tissue inhibitors (TIMPs) [10,[120][121][122][123][124][125]. MMPs perform many biological functions, they are integral to connective tissue homeostasis and their activities are strictly coordinated during epithelial wound repair [124][125][126].…”

“…IL-13 is also produced by a variety of non-hematopoietic cells including airway epithelial cells [119] and bronchial smooth muscle cells [114]. As a Th2 cytokine, IL-13 shares numerous overlapping characteristics with IL-4, where both cytokines promote B cell proliferation, IgE class switching and synthesis in B cells, and induce surface expression of antigens such as CD23 and major histocompatibility complex (MHC) class II [120]. These similarities between IL-13 and IL-4 function can be explained by the fact that the cytokines share a common receptor subunit, IL-4 receptor subunit (IL-4R ).…”