Fibroblast-Derived MMP-14 Regulates Collagen Homeostasis in Adult Skin

Temporal changes in myocardial collagen, matrix metalloproteinases, and their tissue inhibitors in the left ventricular myocardium in experimental chronic mitral regurgitation in rodents

Mitral regurgitation (MR) imposes left ventricular volume overload, triggering rapid ventricular dilatation, increased myocardial compliance, and, ultimately, cardiac dysfunction. Breakdown of the extracellular matrix has been hypothesized to drive these rapid changes, partially from an imbalance in the matrix metalloproteinases (MMPs) and their tissue inhibitors [tissue inhibitors of metalloproteinase (TIMPs)]. In the present study, we developed a rat model of severe MR that mimics the human condition and investigated the temporal changes in extracellular matrix-related genes, collagen biosynthesis proteins, and proteolytic enzymes over a 20-wk period. Male Sprague-Dawley rats were anesthetized to a surgical plane with mechanical ventilation, and a thoracotomy was performed to expose the apex. Using transesophageal ultrasound guidance, a needle was inserted into the beating heart to perforate the anterior mitral leaflet and create severe MR. Animals were survived for 20 wk, with some animals terminated at 2, 10, and 20 wk for analysis of left ventricular tissue. A sham group that underwent the same surgery without mitral leaflet perforation and MR were used as controls. At 2 wk post-MR, increased collagen gene expression was measured, but protein levels of collagen did not corroborate this finding. In parallel, MMP-1-to-TIMP-4, MMP-2-to-TIMP-1, and MMP-2-to-TIMP-3 ratios were significantly elevated, indicating a proteolytic milieu in the myocardium, possibly causing collagen degradation. By 20 wk, many of the initial differences seen in the proteolytic ratios were not observed, with an increase in collagen compared with the 2-wk time point. Altogether, this data indicates that an imbalance in the MMP-to-TIMP ratio may occur early and potentially contribute to the early dilatation and compliance observed structurally. NEW & NOTEWORTHY In this rodent model of severe mitral regurgitation that mimics the human condition, eccentric left ventricular dilatation occurred rapidly and persisted over the 20-wk period with parallel changes in myocardial collagen and matrix metalloproteinases that may drive the extracellular matrix breakdown.

Processed eggshell membrane powder regulates cellular functions and increase MMP-activity important in early wound healing processes

Avian eggshell membrane (ESM) is a natural biomaterial that has been used as an alternative natural bandage to cure wounds, and is available in large quantities from egg industries. We have previously demonstrated that processed eggshell membrane powder (PEP), aiming to be used in a low cost wound healing product, possesses anti-inflammatory properties. In this study, we further investigated effects of PEP on MMP activities in vitro (a dermal fibroblast cell culture system) and in vivo (a mouse skin wound healing model). Three days incubation with PEP in cell culture led to rearrangement of the actin-cytoskeleton and vinculin in focal adhesions and increased syndecan-4 shedding. In addition, we observed increased matrix metalloproteinase type 2 (MMP-2) enzyme activation, without effects on protein levels of MMP-2 or its regulators (membrane type 1 (MT1)-MMP and tissue inhibitor of matrix metalloproteinase type 2 (TIMP-2). Longer incubation (10 days) led to increased protein levels of MMP-2 and its regulators. We also observed an increased alpha-smooth muscle actin (α-SMA) production, suggesting an effect of PEP on myofibroblast differentiation. In vivo, using the mouse skin wound healing model, PEP treatment (3 days) increased MMP activity at the wound edges, along with increased MMP-2 and MMP-9 protein levels, and increased keratinocyte cell proliferation. Altogether, our data suggest PEP stimulates MMP activity, and with a positive effect on early cellular events during wound healing.

Matrix biomechanics and dynamics in pulmonary fibrosis

The composition and mechanical properties of the extracellular matrix are dramatically altered during the development and progression of pulmonary fibrosis. Recent evidence indicates that these changes in matrix composition and mechanics are not only end-results of fibrotic remodeling, but active participants in driving disease progression. These insights have stimulated interest in identifying the components and physical aspects of the matrix that contribute to cell activation and disease initiation and progression. This review summarizes current knowledge regarding the biomechanics and dynamics of the ECM in mouse models and human IPF, and discusses how matrix mechanical and compositional changes might be non-invasively assessed, therapeutically targeted, and biologically restored to resolve fibrosis.

Ozone oil promotes wound healing by increasing the migration of fibroblasts via PI3K/Akt/mTOR signaling pathway

Skin injury affects millions of people via the uncontrolled inflammation and infection. Many cellular components including fibroblasts and signaling pathways such as transforming growth factor-β (TGF-β) were activated to facilitate the wound healing to repair injured tissues. C57BL/6 female mice were divided into control and ozone oil treated groups. Excisional wounds were made on the dorsal skin and the fibroblasts were isolated from granulation tissues. The skin injured mouse model revealed that ozone oil could significantly decrease the wound area and accelerate wound healing compared with control group. QPCR and Western blotting assays showed that ozone oil up-regulated collagen I, α-SMA, and TGF-β1 mRNA and protein levels in fibroblasts. Wound healing assay demonstrated that ozone oil could increase the migration of fibroblasts. Western blotting assay demonstrated that ozone oil increased the epithelial–mesenchymal transition (EMT) process in fibroblasts via up-regulating fibronectin, vimentin, N-cadherin, MMP-2, MMP-9, insulin-like growth factor binding protein (IGFBP)-3, IGFBP5, and IGFBP6, and decreasing epithelial protein E-cadherin and cellular senescence marker p16 expression. Mechanistically, Western blotting assay revealed that ozone oil increased the phosphorylation of PI3K, Akt, and mTOR to regulate the EMT process, while inhibition of PI3K reversed this effect of ozone oil. At last, the results from Cytometric Bead Array (CBA) demonstrated ozone oil significantly decreased the inflammation in fibroblasts. Our results demonstrated that ozone oil facilitated the wound healing via increasing fibroblast migration and EMT process via PI3K/Akt/mTOR signaling pathway in vivo and in vitro. The cellular and molecular mechanisms we found here may provide new therapeutic targets for the treatment of skin injury.

Matrix metalloproteinase collagenolysis in health and disease

The proteolytic processing of collagen (collagenolysis) is critical in development and homeostasis, but also contributes to numerous pathologies. Mammalian interstitial collagenolytic enzymes include members of the matrix metalloproteinase (MMP) family and cathepsin K. While MMPs have long been recognized for their ability to catalyze the hydrolysis of collagen, the roles of individual MMPs in physiological and pathological collagenolysis are less defined. The use of knockout and mutant animal models, which reflect human diseases, has revealed distinct collagenolytic roles for MT1-MMP and MMP-13. A better understanding of temporal and spatial collagen processing, along with the knowledge of the specific MMP involved, will ultimately lead to more effective treatments for cancer, arthritis, cardiovascular conditions, and infectious diseases. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman.

The role of matrix metalloproteinases in aging: Tissue remodeling and beyond

Proteases are a set of enzymes that have been involved in multiple biological processes throughout evolution. Among them, extracellular matrix (ECM) remodeling has emerged as one of the most relevant functions exerted by these proteins, being essential in the regulation of critical events such as embryonic development or tissue homeostasis. Hence, it is not surprising that dysregulation in any protease function that affects ECM homeostasis may contribute to the aging process. Matrix metalloproteinases (MMPs) are one of the most important families of proteases involved in the tight control of ECM remodeling over time. In this review, we will discuss how MMPs and other proteases alter ECM composition and mechanical properties in aging, thereby affecting stem cell niches and the development of senescent phenotypes. Finally, we will summarize recent findings that associate MMPs with the development of age-related diseases, such as neurodegenerative disorders.

Salmon nasal cartilage proteoglycan enhances growth of normal human dermal fibroblast through Erk1/2 phosphorylation

Proteoglycan (PG) is a heavily glycosylated protein, localized to cell surface and extracellular matrix, and has various functions. Recently, it has been gradually revealed that PG interacts with various growth factors and morphogens and regulates cellular functions. Although salmon nasal cartilage PG (Salmon-PG) increases proliferation of immortalized cells, its mechanism remains unclear. In this study, we confirmed the effect of Salmon-PG on normal human dermal fibroblast (NHDF) and investigated the mechanism of PG action on NHDF. Salmon-PG dose- and time-dependently increased NHDF proliferation. Receptor tyrosine kinase array revealed that Salmon-PG increased only Erk1/2 signaling. Erk1/2 phosphorylation was significantly increased by Salmon-PG in a time-(10 min) and dose-(400 or 800 μg/mL) dependent manner. MEK inhibitor suppressed the enhancement of NHDF proliferation by Salmon-PG. The overall findings indicate that Salmon-PG plays a role as a growth factor in NHDF via Erk1/2 activation, suggesting that Salmon-PG contributes to the maintenance of skin homeostasis.