The activity of collagenase-1 is required for keratinocyte migration on a type I collagen matrix

Glu-Trp-ONa or its acylated analogue (R-Glu-Trp-ONa) administration enhances the wound healing in the model of chronic skin wounds in rabbits

The management of chronic skin wounds represents a major therapeutic challenge. The synthesized dipeptide (Glu-Trp-ONa) and its acylated analogue (R-Glu-Trp-ONa) were assessed in the model of nonhealing dermal wounds in rabbits in relation to their healing properties in wound closure. Following wound modeling, the rabbits received a course of intraperitoneal injections of Glu-Trp-ONa or R-Glu-Trp-ONa. Phosphate-buffered saline and Solcoseryl® were applied as negative and positive control agents, respectively. An injection of Glu-Trp-ONa and R-Glu-Trp-ONa decreased the period of wound healing in animals in comparison to the control and Solcoseryl-treated groups. Acylation of Glu-Trp-ONa proved to be beneficial as related to the healing properties of the dipeptide. Subsequent zymography analyses showed that the applied peptides decreased the proteolytic activity of matrix metalloproteinases MMP-9, MMP-8, and MMP-2 in the early inflammatory phase and reversely increased the activity of MMP-9, MMP-8, and MMP-1 in the remodeling phase. Histological analyses of the wound sections (hematoxylin-eosin, Mallory's staining) confirmed the enhanced formation of granulation tissue and re-epithelialization in the experimental groups. By administering the peptides, wound closures increased significantly through the modulation of the MMPs' activity, indicating their role in wound healing.

Matrix remodeling by MMPs during wound repair

Repair following injury involves a range of processes - such as re-epithelialization, scar formation, angiogenesis, inflammation, and more - that function, often together, to restore tissue architecture. MMPs carry out diverse roles in all of these activities. In this article, we discuss how specific MMPs act on ECM during two critical repair processes: re-epithelialization and resolution of scar tissue. For wound closure, we discuss how two MMPs - MMP1 in human epidermis and MMP7 in mucosal epithelia - facilitate re-epithelialization by cleaving different ECM or ECM-associated proteins to affect similar integrin:matrix adhesion. In scars and fibrotic tissues, we discuss that a variety of MMPs carry out a diverse range of activities that can either promote or limit ECM deposition. However, few of these MMP-driven activities have been demonstrated to be due a direct action on ECM.

Immunohistochemical analysis on MMP-2 and MMP-9 for wound age determination

We performed immunohistochemical study combined with morphometrical analyses in order to examine the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 using 55 human skin wounds of different ages: group I, 0-3 days (n = 16); II, 4-7 days (n = 11); III, 9-14 days (n = 16); and IV, 17-21 days (n = 12). Immunopositive reactions for MMP-2 were observed in all human skin specimens including uninjured skin as control. The number of MMP-2(+) macrophages was significantly increased in accordance with wound ages. In contrast to MMP-2, no MMP-9(+) signals were detected in uninjured and wound specimens aged less than 1 day. However, the number of MMP-9(+) macrophages profoundly appeared in groups II and III. Morphometrically, in all of wound samples aged 9-12 days, MMP-2(+) cell number was more than 20. On the contrary, most of the remaining samples had <20 positive cells. However, only one sample (a 7-day-old wound) showed 21 positive cells. Thus, with regard to practical applicability with forensic safety, MMP-2(+) macrophages of >20 would indicate a wound age of 7-12 days. Additionally, 10 out of 12 wound specimens aged 9-12 days showed the MMP-2(+) cell number of >25, implying that MMP-2(+) cell number of >25 would indicate the wound age of 9-12 days. On the contrary, all wound samples aged 3-14 days except for only one sample had MMP-9(+) cell number of >30, indicating that MMP-9(+) cell number of >30 would indicate the wound age of 3-14 days. Collectively, MMP-2 seemed to be more distinct marker, compared with MMP-9.

Matrix metalloproteinases regulate extracellular levels of SDF-1/CXCL12, IL-6 and VEGF in hydrogen peroxide-stimulated human periodontal ligament fibroblasts

Periodontitis is a highly prevalent infectious disease characterized by the progressive inflammatory destruction of tooth-supporting structures, leading to tooth loss. The underling molecular mechanisms of the disease are incompletely understood, precluding the development of more efficient screening, diagnostic and therapeutic approaches. We investigated the interrelation of three known effector mechanisms of the cellular response to periodontal infection, namely reactive oxygen species (ROS), matrix metalloproteinases (MMPs) and cytokines in primary cell cultures of human periodontal ligament fibroblast (hPDLF). We demonstrated that ROS increase the activity/levels of gelatinolytic MMPs, and stimulate cytokine secretion in hPDLF. Additionally, we proved that MMPs possesses immune modulatory capacity, regulating the secreted levels of cytokines in ROS-stimulated hPDLF cultures. This evidence provides further insight in the molecular pathogenesis of periodontitis, contributing to the future development of more effective therapies.

Biomechanical and biochemical remodeling of stromal extracellular matrix in cancer

The extracellular matrix (ECM) provides structural and biochemical signals that regulate cell function. A well-controlled balance between cells and surroundings (i.e., dynamic reciprocity) is crucial for regulating ECM architecture. During cancer progression, epithelial cells undergo genetic alterations which, together with stromal changes including ECM remodeling, disturb the homeostatic dynamics of the epithelium. A parallel organization of stromal ECM fibrils is associated with tumorigenic responses. In an emerging paradigm, continuous and progressive regulation via mechanical forces and aberrant signaling are believed to be responsible for tumor-associated ECM remodeling. In this review we discuss the discrete biomechanical and biochemical mechanisms that underlie these architectural changes and highlight their particular relevance to the regulation of the alignment of ECM in the mesenchymal stroma.

Matrix metalloproteinase interactions with collagen and elastin

Most abundant in the extracellular matrix are collagens, joined by elastin that confers elastic recoil to the lung, aorta, and skin. These fibrils are highly resistant to proteolysis but can succumb to a minority of the matrix metalloproteinases (MMPs). Considerable inroads to understanding how such MMPs move to the susceptible sites in collagen and then unwind the triple helix of collagen monomers have been gained. The essential role in unwinding of the hemopexin-like domain of interstitial collagenases or the collagen binding domain of gelatinases is highlighted. Elastolysis is also facilitated by the collagen binding domain in the cases of MMP-2 and MMP-9, and remote exosites of the catalytic domain in the case of MMP-12.

Integrins in Wound Healing

Significance: Regulation of cell adhesions during tissue repair is fundamentally important for cell migration, proliferation, and protein production. All cells interact with extracellular matrix proteins with cell surface integrin receptors that convey signals from the environment into the nucleus, regulating gene expression and cell behavior. Integrins also interact with a variety of other proteins, such as growth factors, their receptors, and proteolytic enzymes. Re-epithelialization and granulation tissue formation are crucially dependent on the temporospatial function of multiple integrins. This review explains how integrins function in wound repair. Recent Advances: Certain integrins can activate latent transforming growth factor beta-1 (TGF-β1) that modulates wound inflammation and granulation tissue formation. Dysregulation of TGF-β1 function is associated with scarring and fibrotic disorders. Therefore, these integrins represent targets for therapeutic intervention in fibrosis. Critical Issues: Integrins have multifaceted functions and extensive crosstalk with other cell surface receptors and molecules. Moreover, in aberrant healing, integrins may assume different functions, further increasing the complexity of their functionality. Discovering and understanding the role that integrins play in wound healing provides an opportunity to identify the mechanisms for medical conditions, such as excessive scarring, chronic wounds, and even cancer. Future Directions: Integrin functions in acute and chronic wounds should be further addressed in models better mimicking human wounds. Application of any products in acute or chronic wounds will potentially alter integrin functions that need to be carefully considered in the design.

Deguelin inhibits the migration and invasion of U-2 OS human osteosarcoma cells via the inhibition of matrix metalloproteinase-2/-9 in vitro

Osteosarcoma is the most common malignant primary bone tumor in children and young adults and lung metastasis is the main cause of death in those patients. Deguelin, a naturally occurring rotenoid, is known to be an Akt inhibitor and to exhibit cytotoxic effects, including antiproliferative and anticarcinogenic activities, in several cancers. In the present study, we determined if deguelin would inhibit migration and invasion in U-2 OS human osteosarcoma cells. Deguelin significantly inhibited migration and invasion of U-2 OS human osteosarcoma cells which was associated with a reduction of activities of matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9). Furthermore, results from western blotting indicated that deguelin decreased the cell proliferation and cell growth-associated protein levels, such as SOS1, PKC, Ras, PI3K, p-AKT(Ser473), IRE-1α, MEKK3, iNOS, COX2, p-ERK1/2, p-JNK1/2, p-p38; the cell motility and focal adhesion-associated protein levels, such as Rho A, FAK, ROCK-1; the invasion-associated protein levels, such as TIMP1, uPA, MMP-2. MMP-9, MMP-13, MMP-1 and VEGF in U-2 OS cells. Confocal microscopy revealed that deguelin reduced NF-κB p65, Rho A and ROCK-1 protein levels in cytosol. MMP-7, MMP-9 and Rho A mRNA levels were suppressed by deguelin. These in vitro results provide evidence that deguelin may have potential as a novel anti-cancer agent for the treatment of osteosarcoma and provides the rationale for in vivo studies in animal models.

Does collagen trigger the recruitment of osteoblasts into vacated bone resorption lacunae during bone remodeling?

Osteoblast recruitment during bone remodeling is obligatory to re-construct the bone resorbed by the osteoclast. This recruitment is believed to be triggered by osteoclast products and is therefore likely to start early during the remodeling cycle. Several osteoclast products with osteoblast recruitment potential are already known. Here we draw the attention on the osteoblast recruitment potential of the collagen that is freshly demineralized by the osteoclast. Our evidence is based on observations on adult human cancellous bone, combined with in vitro assays. First, freshly eroded surfaces where osteoblasts have to be recruited show the presence of non-degraded demineralized collagen and close cell-collagen interactions, as revealed by electron microscopy, while surface-bound collagen strongly attracts osteoblast lineage cells in a transmembrane migration assay. Compared with other extracellular matrix molecules, collagen's potency was superior and only equaled by fibronectin. Next, the majority of the newly recruited osteoblast lineage cells positioned immediately next to the osteoclasts exhibit uPARAP/Endo180, an endocytic collagen receptor reported to be involved in collagen internalization and cell migration in various cell types, and whose inactivation is reported to lead to lack of bone formation and skeletal deformities. In the present study, an antibody directed against this receptor inhibits collagen internalization in osteoblast lineage cells and decreases to some extent their migration to surface-bound collagen in the transmembrane migration assay. These complementary observations lead to a model where collagen demineralized by osteoclasts attracts surrounding osteoprogenitors onto eroded surfaces, and where the endocytic collagen receptor uPARAP/Endo180 contributes to this migration, probably together with other collagen receptors. This model fits recent knowledge on the position of osteoprogenitor cells immediately next to remodeling sites in adult human cancellous bone.

Eicosanoids and Keratinocytes in Wound Healing

Significance: Eicosanoids are biologically active lipid mediators derived from arachidonic acid that are important in injury and inflammatory responses. Cyclooxygenase-1 and cyclooxygenase-2 mediate the production of prostanoids, whereas 5-lipoxygenase mediates the production of leukotrienes and hydroxyeicosatetraenoic acids. These lipid mediators have traditionally been known to recruit cells of the immune system to a site of injury and inflammation. However, they also interact with various cells that are resident to the wound bed, including modulation of keratinocyte activity. Recent Advances: Recent work has identified multiple prostanoid and leukotriene receptors on keratinocytes, indicating that eicosanoids directly interact with them. Recent work also shows that keratinocytes are capable of producing prostanoids and leukotrienes. Critical Issues: Much of the critical work has been performed in cell culture and mouse in vivo models. This has greatly expanded our understanding of the eicosanoid interactions with keratinocytes and wound healing in general. However, few of these in vivo models have been able to critically evaluate keratinocyte migration and re-epithelialization. Future Directions: As research continues in this exciting field, the cellular pathways stimulated by the eicosanoids will become better defined. Future research with excisional wound models in mice and pigs and ex vivo human skin models will better isolate the contribution of eicosanoid-mediated effects on keratinocyte migration and re-epithelialization.

Tumour-stroma crosstalk in the development of squamous cell carcinoma

Squamous cell carcinoma (SCC) represents one of the most frequently diagnosed tumours and contributes significant mortality worldwide. Recent deep sequencing of cancer genomes has identified common mutations in SCC arising across different tissues highlighting perturbation of squamous differentiation as a key event. At the same time significant data have been accumulating to show that common tumour-stroma interactions capable of driving disease progression are also evident when comparing SCC arising in different tissues. We and others have shown altered matrix composition surrounding SCC can promote tumour development. This review focuses on some of the emerging data with particular emphasis on SCC of head and neck and skin with discussion on the potential tumour suppressive properties of a normal microenvironment. Such data indicate that regardless of the extent and type of somatic mutation it is in fact the tumour context that defines metastatic progression.

The application of the starfish hatching enzyme for the improvement of scar and keloid based on the fibroblast-populated collagen lattice

Various bioactivities of the starfish hatching enzyme (HE) including collagen gel contraction, MMPs activity, hydroxyproline release, and gene regulation based on the fibroblast-populated collagen lattice (FPCL) in three-dimensional medium were investigated for the improvement of scar and keloid. The starfish HE significantly inhibited the collagen gel contraction over 2 days of culture. MMP-2 and MMP-9 activities were also identified by gelatin zymography and RT-PCR products with both HE and collagenase treatments, which resulted in the high amount of hydroxyproline release. The HE treatment on the FPCL significantly inhibited the fibroblast proliferation at 3 days of culture. The LPS-induced NO level and iNOS mRNA expression at low concentrations of HE presented a certain ability to inflammatory response. The COX-2 mRNA from the FPCL indicated no significant inflammation-mediated activity at 5 μg/mL of HE, whereas the cytokines of TNF-α and IL-1β were significantly higher than those of the control. Hence, the starfish hatching enzyme can regulate the fibroblast-populated collagen gel conditions by the contraction, MMP production, inflammatory gene expression, etc. Therefore, the starfish HE could be a potential cosmeceutical to heal the scar and keloid tissue.

Matrix metalloproteinases in inflammation

BACKGROUND

Matrix metalloproteinases (MMPs) are a family of ubiquitously expressed zinc-dependent endopeptidases with broad substrate specificity and strictly regulated tissue specific expression. They are expressed in physiological situations and pathological conditions involving inflammation. MMPs regulate several functions related to inflammation including bioavailability and activity of inflammatory cytokines and chemokines. There is also evidence that MMPs regulate inflammation in tumor microenvironment, which plays an important role in cancer progression.

SCOPE OF REVIEW

Here, we discuss the current view on the role of MMPs in the regulation of inflammation.

MAJOR CONCLUSIONS

MMPs modulate inflammation by regulating bioavailability and activity of cytokines, chemokines, and growth factors, as well as integrity of physical tissue barriers. MMPs are also involved in immune evasion of tumor cells and in regulation of inflammation in tumor microenvironment.

GENERAL SIGNIFICANCE

There is increasing evidence for non-matrix substrates of MMPs that are related to regulation of inflammatory processes. New methods have been employed for identification of the substrates of MMPs in inflammatory processes in vivo. Detailed information on the substrates of MMPs may offer more specific and effective ways of inhibiting MMP function by blocking the cleavage site in substrate or by inhibition of the bioactivity of the substrate. It is expected, that more precise information on the MMP-substrate interaction may offer novel strategies for therapeutic intervention in inflammatory diseases and cancer without blocking beneficial actions of MMPs. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.

Potential pathway of anti-inflammatory effect by New Zealand honeys

The role of honey in wound healing continues to attract worldwide attention. This study examines the anti-inflammatory effect of four honeys on wound healing, to gauge its efficacy as a treatment option. Isolated phenolics and crude extracts from manuka (Leptospermum scoparium), kanuka (Kunzea ericoides), clover (Trifolium spp.), and a manuka/kanuka blend of honeys were examined. Anti-inflammatory assays were conducted in HEK-Blue™-2, HEK-Blue™-4, and nucleotide oligomerization domain (NOD)2-Wild Type (NOD2-WT) cell lines, to assess the extent to which honey treatment impacts on the inflammatory response and whether the effect was pathway-specific. Kanuka honey, and to a lesser extent manuka honey, produced a powerful anti-inflammatory effect related to their phenolic content. The effect was observed in HEK-Blue™-2 cells using the synthetic tripalmitoylated lipopeptide Pam3CysSerLys4 (Pam3CSK4) ligand, suggesting that honey acts specifically through the toll-like receptor (TLR)1/TLR2 signaling pathway. The manuka/kanuka blend and clover honeys had no significant anti-inflammatory effect in any cell line. The research found that kanuka and manuka honeys have an important role in modulating the inflammatory response associated with wound healing, through a pathway-specific effect. The phenolic content of honey correlates with its effectiveness, although the specific compounds involved remain to be determined.

Integrin Regulation of Epidermal Functions in Wounds

Significance: Integrins are bidirectional signaling receptors for extracellular matrix that regulate both inside-out signaling that controls keratinocyte-mediated changes to the wound microenvironment and outside-in signaling that controls keratinocyte responses to microenvironmental changes. As such, integrins represent attractive therapeutic targets for treatment of chronic wounds or general promotion of wound healing. Advances in wound management are particularly important as the elderly and diabetic populations within the United States continue to grow. Recent Advances: Although integrins are best known for mediating cell adhesion and migration, integrins in wound epidermis also control cell survival, proliferation, matrix remodeling, and paracrine crosstalk to other cellular compartments of the wound. Importantly, the concept of targeting integrins in the clinic has been established for treatment of certain cancers and other diseases, laying the groundwork for similar exploitation of integrins as targets to treat chronic wounds. Critical Issues: Despite their attractiveness as therapeutic targets, integrins have complex roles in wound healing that are impacted by both their own expression and a highly dynamic wound microenvironment that determines ligand availability. Therefore, identifying relevant integrin ligands in the wound and understanding both distinct and overlapping functions that different integrins play in the epidermis will be critical to determine their precise roles in wound healing. Future Directions: Future research should focus on gaining a thorough understanding of the highly coordinated functions of different integrins in wound epidermis, and on determining which of these functions go awry in pathological wounds. This focus should facilitate development of integrin-targeting therapeutics for treating chronic wounds.

Interleukin-17A stimulates migration of periodontal ligament fibroblasts via p38 MAPK/NF-κB -dependent MMP-1 expression

Interleukin-17 (IL-17) is a cytokine secreted predominantly by Th17 cells. Although IL-17 is primarily associated with the induction of tissue inflammation, the other biological functions of IL-17, including its wound-healing functions, have yet to be thoroughly explored. Fibroblast proliferation and migration play essential roles in periodontal wound-healing responses. In this study, we report that IL-17A can increase the migration and expression of matrix metalloproteinase (MMP)-1 in human periodontal ligament (PDL) fibroblasts but has no effect on PDL fibroblast proliferation. IL-17A-induced MMP-1 expression led to cell migration, which was attenuated by pre-treatment with IL-17 receptor neutralizing antibody and small interfering RNA (siRNA) for MMP-1. The IL-17A-induced cell migration was also attenuated by its tissue inhibitor of matrix metalloproteinase (TIMP)-1. In addition, a p38 mitogen-activated protein kinase (MAPK) inhibitor (SB203580) inhibited IL-17A-induced increase of the migration and MMP-1 upregulation of PDL fibroblasts. The involvement of p38 MAPK in IL-17A-induced MMP-1 expression and cell migration was further confirmed by transfection of p38α siRNA. A nuclear factor kappaB (NF-κB) inhibitor (pyrrolidine dithiocarbamate) also suppressed the cell migration and MMP-1 expression enhanced by IL-17A. Moreover, transfection with p38α siRNA inhibited IL-17A-induced NF-κB nuclear translocation as well as NF-κB binding activity. Our results suggest that IL-17A enhances the migration of PDL fibroblasts by increasing MMP-1 expression through the IL-17 receptor, p38 MAPK, and NF-κB signal transduction pathways.

Human skin organ culture for assessment of chemically induced skin damage

The move away from animal models for skin safety testing is inevitable. It is a question of when, not if. As skin safety studies move away from traditional animal-based approaches, a number of replacement technologies are becoming available. Human skin in organ culture is one such technology. Organ-cultured skin has several features that distinguish it from other technologies. First and foremost, organ-cultured skin is real skin. Almost by definition, therefore, it approximates the intact skin better than other alternative models. Organ culture is an easy-to-use and relatively inexpensive approach to preclinical safety assessment. Although organ culture is not likely to replace high-throughput enzyme assays or monolayer culture/skin equivalent cultures for initial compound assessment, organ culture should find use when the list of compounds to be evaluated is small and when simpler models have narrowed the dose range. Organ-cultured skin also provides a platform for mechanistic studies.

α2β1 Integrin

The α2β1 integrin, also known as VLA-2, GPIa-IIa, CD49b, was first identified as an extracellular matrix receptor for collagens and/or laminins [55, 56]. It is now recognized that the α2β1 integrin serves as a receptor for many matrix and nonmatrix molecules [35, 79, 128]. Extensive analyses have clearly elucidated the α2 I domain structural motifs required for ligand binding, and also defined distinct conformations that lead to inactive, partially active or highly active ligand binding [3, 37, 66, 123, 136, 137, 140]. The mechanisms by which the α2β1 integrin plays a critical role in platelet function and homeostasis have been carefully defined via in vitro and in vivo experiments [76, 104, 117, 125]. Genetic and epidemiologic studies have confirmed human physiology and disease states mediated by this receptor in immunity, cancer, and development [6, 20, 21, 32, 43, 90]. The role of the α2β1 integrin in these multiple complex biologic processes will be discussed in the chapter.

Epithelial mesenchymal transition-like phenomenon in trabecular meshwork cells

The trabecular meshwork (TM) is a major component of the conventional outflow pathway and the excess extracellular matrix (ECM), and fibrosis in the TM causes increased outflow resistance. In this study, we first investigated the effects of several ECM components in the induction of an epithelial mesenchymal transition (EMT)-like phenomenon in TM cells. TM cells were isolated from cynomolgus monkeys (Macaca fascicularis). The cells were cultured in ECM-coated dishes and then subjected to both western blot analysis and immunocytochemistry to measure the levels of EMT-associated markers. Cell motility was assessed using wound healing and chemotaxis assays. We found that type I collagen, fibronectin and laminin induced the dissociation of cell-cell contact and elongation of actin stress fibers in the cultured monkey TM cells. In addition, following the same stimulation of the ECM, the expression of mesenchymal markers, such as fibronectin and α-smooth muscle actin, and the phosphorylation of Smad2 increased in the TM cells. Our results showed the significant acceleration of TM cellular motility following stimulation with type I collagen, fibronectin and laminin. These phenomena were inhibited by the c-Jun N-terminal kinase (JNK) inhibitor SP600125. In addition, siRNA against paxillin was transfected to evaluate the association between paxillin and the EMT-like phenomenon. The knockdown of paxillin expression by transfection with siRNA blocked the EMT-like alteration of the cellular characteristics and chemotaxis toward transforming growth factor-β2 in the cultured TM cells. Our results showed that the ECM-JNK-paxillin pathway induced an EMT-like phenomenon in TM cells, resulting in the abundant expression of fibronectin and activation of motility in TM cells. This EMT-like phenomenon could result in aberrant conditions in the aqueous outflow pathway in glaucomatous eyes.

Cdc42 inhibits ERK-mediated collagenase-1 (MMP-1) expression in collagen-activated human keratinocytes

Following injury, keratinocytes switch gene expression programs from the one that promotes differentiation to the one that supports migration. A common feature of human wounds and ulcerations of any form is the expression of matrix metalloproteinase 1 (MMP-1; collagenase-1) by leading-edge basal keratinocytes migrating across the dermal or provisional matrix. Induction of MMP-1 occurs by signaling from the α2β1 integrin in contact with dermal fibrillar type I collagen, and the activity of MMP-1 is required for human keratinocytes to migrate on collagen. Thus, MMP-1 serves a critical role in the repair of damaged human skin. Here, we evaluated the mechanisms controlling MMP-1 expression in primary human keratinocytes from neonatal foreskin and adult female skin. Our results demonstrate that shortly following contact with type I collagen extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase were markedly activated, whereas c-Jun N-terminal kinase (JNK) phosphorylation remained at basal levels. ERK inhibition markedly blocked collagen-stimulated MMP-1 expression in keratinocytes. In contrast, inhibiting p38 or JNK pathways had no effect on MMP-1 production. Moreover, investigating the role of Rho GTPases revealed that Cdc42 attenuates MMP-1 expression by suppressing ERK activity. Thus, our data indicate that injured keratinocytes induce MMP-1 expression through ERK activation, and this process is negatively regulated by Cdc42 activity.

Clinical and economic assessment of diabetic foot ulcer debridement with collagenase: results of a randomized controlled study

BACKGROUND

Despite significant advances, the treatment of diabetic foot ulcers (DFUs) remains a major therapeutic challenge for clinicians, surgeons, and other health care professionals. There is an urgent need for new strategies with clinically effective interventions to treat DFUs to reduce the burden of care in an efficient and cost-effective way.

OBJECTIVE

This randomized trial evaluated and compared the clinical effectiveness, tolerability, and costs of clostridial collagenase ointment (CCO) debridement to that of debridement using saline moistened gauze (SMG) and selective sharp debridement for the treatment of DFUs.

METHODS

Randomized, controlled, parallel group, multicenter, open-label, 12-week study of 48 patients with neuropathic DFUs randomized to 4 weeks of treatment with either CCO or SMG after baseline surgical debridement. The primary end point was the condition of the ulcer bed at the end of treatment as measured using a standardized wound assessment tool. Secondary end points were the percentage of reduction in wound area and therapeutic response rates. Adverse events were monitored for the tolerability analysis. In addition, a comparative cost-effectiveness analysis was performed from the perspective of the Centers for Medicare and Medicaid Services as a payer.

RESULTS

Both the CCO and SMG groups had significantly improved wound assessment scores after 4 weeks of treatment (CCO, -2.5, P = 0.007; SMG, -3.4, P = 0.006). Only CCO treatment resulted in a statistically significant decrease from baseline in the mean wound area at the end of treatment (P = 0.0164) and at the end of follow-up (P = 0.012). In addition, the CCO group exhibited a significantly better response rate at the end of follow-up compared with the SMG group (0.92 vs 0.75, P < 0.05). Reported adverse events were similar between the 2 treatment groups. None of the reported adverse events were considered to be related to treatment. The economic analysis indicated that the direct mean costs per responder in the physician office setting of care were $832 versus $1042 for the CCO group versus the SMG group, whereas the direct mean costs per responder in the hospital outpatient department setting were $1607 versus $1980.

CONCLUSIONS

CCO treatment provides equivalent debridement of DFUs similar to SMG while fostering better progress toward healing as measured by decreasing wound area over time and improved response rates at the end of follow-up. In addition, CCO yields a more favorable cost-effectiveness ratio in both the physician office and hospital outpatient department settings of care. ClinicalTrials.gov identifier: NCT01056198.

Matrix metalloproteinase (MMP)-1 induces lung alveolar epithelial cell migration and proliferation, protects from apoptosis, and represses mitochondrial oxygen consumption

Idiopathic pulmonary fibrosis is a devastating lung disorder of unknown etiology. Although its pathogenesis is unclear, considerable evidence supports an important role of aberrantly activated alveolar epithelial cells (AECs), which produce a large variety of mediators, including several matrix metalloproteases (MMPs), which participate in fibroblast activation and lung remodeling. MMP-1 has been shown to be highly expressed in AECs from idiopathic pulmonary fibrosis lungs although its role is unknown. In this study, we explored the role of MMP-1 in several AECs functions. Mouse lung epithelial cells (MLE12) transfected with human Mmp-1 showed significantly increased cell growth and proliferation at 36 and 48 h of culture (p < 0.01). Also, MMP-1 promoted MLE12 cell migration through collagen I, accelerated wound closing, and protected cells from staurosporine- and bleomycin-induced apoptosis compared with mock cells (p < 0.01). MLE12 cells expressing human MMP-1 showed a significant repression of oxygen consumption ratio compared with the cells with the empty vector. As under hypoxic conditions hypoxia-inducible factor-1α (HIF-1α) mediates a transition from oxidative to glycolytic metabolism, we analyzed activation of HIF-1α. Ηigher activation of this factor was detected in MMP-1-transfected cells under normoxia and hypoxia. Likewise, a significant decrease of both total and mitochondrial reactive oxygen species was observed in MMP-1-transfected cells. Paralleling these findings, attenuation of MMP-1 expression by shRNA in A549 (human) AECs markedly reduced proliferation and migration (p < 0.01) and increased the oxygen consumption ratio. These findings indicate that epithelial expression of MMP-1 inhibits mitochondrial function, increases HIF-1α expression, decreases reactive oxygen species production, and contributes to a proliferative, migratory, and anti-apoptotic AEC phenotype.

Tetraspanin CD9 promotes the invasive phenotype of human fibrosarcoma cells via upregulation of matrix metalloproteinase-9

Tumor cell metastasis, a process which increases the morbidity and mortality of cancer patients, is highly dependent upon matrix metalloproteinase (MMP) production. Small molecule inhibitors of MMPs have proven unsuccessful at reducing tumor cell invasion in vivo. Therefore, finding an alternative approach to regulate MMP is an important endeavor. Tetraspanins, a family of cell surface organizers, play a major role in cell signaling events and have been implicated in regulating metastasis in numerous cancer cell lines. We stably expressed tetraspanin CD9 in an invasive and metastatic human fibrosarcoma cell line (CD9-HT1080) to investigate its role in regulating tumor cell invasiveness. CD9-HT1080 cells displayed a highly invasive phenotype as demonstrated by matrigel invasion assays. Statistically significant increases in MMP-9 production and activity were attributed to CD9 expression and were not due to any changes in other key tetraspanin complex members or MMP regulators. Increased invasion of CD9-HT1080 cells was reversed upon silencing of MMP-9 using a MMP-9 specific siRNA. Furthermore, we determined that the second extracellular loop of CD9 was responsible for the upregulation of MMP-9 production and subsequent cell invasion. We demonstrated for the first time that tetraspanin CD9 controls HT1080 cell invasion via upregulation of an integral member of the MMP family, MMP-9. Collectively, our studies provide mounting evidence that altered expression of CD9 may be a novel approach to regulate tumor cell progression.

Visualizing osteogenesis in vivo within a cell-scaffold construct for bone tissue engineering using two-photon microscopy

Tissue-engineering therapies have shown early success in the clinic, however, the cell-biomaterial interactions that result in successful outcomes are not yet well understood and are difficult to observe. Here we describe a method for visualizing bone formation within a tissue-engineered construct in vivo, at a single-cell resolution, and in situ in three dimensions using two-photon microscopy. First, two-photon microscopy and histological perspectives were spatially linked using fluorescent reporters for cells in the skeletal lineage. In the process, the tissue microenvironment that precedes a repair-focused study was described. The distribution and organization of type I collagen in the calvarial microenvironment was also described using its second harmonic signal. Second, this platform was used to observe in vivo, for the first time, host cells, donor cells, scaffold, and new bone formation within cell-seeded constructs in a bone defect. We examined constructs during bone repair 4 and 6 weeks after implantation. New bone formed on scaffolds, primarily by donor cells. Host cells formed a new periosteal layer that covered the implant. Scaffold resorption appeared to be site specific, where areas near the top were removed and deeper areas were completely embedded in new mineral. Visualizing the in vivo progression of the cell and scaffold microenvironment will contribute to our understanding of tissue-engineered regeneration and should lead to the development of more streamlined and therapeutically powerful approaches.

Extracellular matrix signaling in morphogenesis and repair

The extracellular matrix (ECM) is critically important for many cellular processes including growth, differentiation, survival, and morphogenesis. Cells remodel and reshape the ECM by degrading and reassembling it, playing an active role in sculpting their surrounding environment and directing their own phenotypes. Both mechanical and biochemical molecules influence ECM dynamics in multiple ways; by releasing small bioactive signaling molecules, releasing growth factors stored within the ECM, eliciting structural changes to matrix proteins which expose cryptic sites and by degrading matrix proteins directly. The dynamic reciprocal communication between cells and the ECM plays a fundamental roll in tissue development, homeostasis, and wound healing.

Acute and chronic wound fluids influence keratinocyte function differently

Wound healing requires a proper functioning of keratinocytes that migrate, proliferate and lead to a competent wound closure. Impaired wound healing might be due to a disturbed keratinocyte function caused by the wound environment. Basically, chronic wound fluid (CWF) differs from acute wound fluid (AWF). The aim of this study was to analyse the effects of AWF and CWF on keratinocyte function. We therefore investigated keratinocyte migration and proliferation under the influence of AWF and CWF using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test and scratch assay. We further measured the gene expression by qRT-PCR regarding growth factors and matrixmetalloproteinases (MMPs) involved in regeneration processes. AWF had a positive impact on keratinocyte proliferation over time, whereas CWF had an anti-proliferative effect. Keratinocyte migration was significantly impaired by CWF in contrast to an undisturbed wound closure under the influence of AWF. MMP-9 expression was strongly upregulated by CWF compared with AWF. Keratinocyte function was significantly impaired by CWF. An excessive induction of MMP-9 by CWF might lead to a permanent degradation of extracellular matrix and thereby prevent wounds from healing.

Stability of serum eye drops after storage of 6 months

PURPOSE

Serum eye drops are used for the treatment of ocular surface disease (eg, Sicca syndrome). The objective of this experimental study was to investigate whether they maintain their wound-healing potency after a prolonged storage of 6 months at -20 °C and to find a parameter that can serve as a quality and stability indicator.

METHODS

After obtaining whole blood from 10 volunteers and preparing 100% (AS100), 50% (AS50), and 20% (AS20) serum eye drops, epitheliotrophic factors including EGF, fibronectin, vitamins A and E, albumin, and immunoglobulin A were quantified before and after storage for 7 days at 6 °C or 3 and 6 months at -20 °C. Human corneal epithelial (HCE) cell lines were used to investigate proliferation, migration, and overall wound healing potency of the cells in response to different serum preparations. The proliferation, migration, and wound healing of HCE cells were measured after incubation with different serum eye drop concentrations and after different storage conditions.

RESULTS

The concentration of epidermal growth factor, fibronectin, vitamins A and E, immunoglobulin A, and albumin showed no significant reduction over the test period. Proliferation, migration, and wound healing of HCE cells was significantly better after incubation with undiluted serum in comparison with diluted serum. No significant loss of cytokine concentration, wound healing, and proliferation effect in HCE culture of AS100, AS50, and AS20 could be detected over the 6 months of storage.

CONCLUSIONS

The concentration of a spectrum of cytokines involved in corneal epithelial wound healing and the epitheliothrophic effect of serum are not significantly changed after a prolonged storage of 6 months at -20 °C. Hence, it seems justifiable to provide patients with appropriate freezer capacity with a 6-month supply of autologous serum eye drops. Albumin--which is known to be relevant for ocular surface health--could serve as a cost-effective parameter for stability controls.

Matrix metalloproteinase 9 (MMP-9)-dependent processing of βig-h3 protein regulates cell migration, invasion, and adhesion

Cell migration is critically involved in inflammation, cancer, and development. In this study, transforming growth factor-β-induced protein (βig-h3) was identified as a substrate of matrix metalloproteinase-9 (MMP-9) by site-directed mutagenesis. βig-h3 has two cleavage sites with the consensus sequence Pro-Xaa-Xaa-Hy-(Ser/Thr) (Hy is a hydrophobic amino acid) (PGSFT beginning at amino acid 135 and PPMGT beginning at amino acid 501). Using recombinant human βig-h3 and MMP-9, βig-h3 from βig-h3-transfected HEK293F cells, and MMP-9 from MMP-9-transfected HEK293F cells, human macrophages, and neutrophils, we found that MMP-9 proteolytically cleaves βig-h3. Cleavage leads to the loss of its adhesive property and its release from extracellular matrix proteins, collagen IV, and fibronectin. Spheroids formed by increased cell-cell interactions were observed in βig-h3-transfected HEK293F cells but not in vehicle-transfected HEK293F cells. In human glioma U87MG cells, MMP-9 constitutive overexpression resulted in endogenous βig-h3 cleavage. βig-h3 cleavage by MMP-9 led to increased cell invasion, and βig-h3 knockdown also resulted in increased cell invasion. The βig-h3 fragment cleaved by MMP-9 could bind to the surface of macrophages, and it may play a role as a peptide chemoattractant by inducing macrophage migration via focal adhesion kinase/Src-mediated signal activation. Thus, intact βig-h3 is responsible for cell migration inhibition, cell-cell contact, and cell-extracellular matrix interaction. Experimental evidence indicates that MMP-9-cleaved βig-h3 plays a role in MMP-9-mediated tumor cell and macrophage migration.

The molecular basis of wound healing processes induced by lithospermi radix: a proteomics and biochemical analysis

Lithospermi Radix (LR) is an effective traditional Chinese herb in various types of wound healing; however, its mechanism of action remains unknown. A biochemical and proteomic platform was generated to explore the biological phenomena associated with LR and its active component shikonin. We found that both LR ethanol extracts and shikonin are able to promote cell proliferation by up to 25%. The results of proteomic analysis revealed that twenty-two differentially expressed proteins could be identified when fibroblast cells were treated with LR or shikonin. The functions of those proteins are associated with antioxidant activity, antiapoptosis activity, the regulation of cell mobility, the secretion of collagen, the removal of abnormal proteins, and the promotion of cell proliferation, indicating that the efficacy of LR in wound healing may be derived from a synergistic effect on a number of factors induced by the herbal medicine. Furthermore, an animal model confirmed that LR is able to accelerate wound healing on the flank back of the SD rats. Together these findings help to pinpoint the molecular basis of wound healing process induced by LR.

The Pseudomonas aeruginosa quorum sensing signal molecule N-(3-oxododecanoyl) homoserine lactone enhances keratinocyte migration and induces Mmp13 gene expression in vitro

Re-epithelialization is an essential step of wound healing involving three overlapping keratinocyte functions: migration, proliferation and differentiation. While quorum sensing (QS) is a cell density-dependent signaling system that enables bacteria to regulate the expression of certain genes, the QS molecule N-(3-oxododecanoyl) homoserine lactone (AHL) exerts effects also on mammalian cells in a process called inter-kingdom signaling. Recent studies have shown that AHL improves epithelialization in in vivo wound healing models but detailed understanding of the molecular and cellular mechanisms are needed. The present study focused on the AHL as a candidate reagent to improve wound healing through direct modulation of keratinocyte's activity in the re-epithelialization process. Results indicated that AHL enhances the keratinocyte's ability to migrate in an in vitro scratch wound healing model probably due to the high Mmp13 gene expression analysis after AHL treatment that was revealed by real-time RT-PCR. Inhibition of activator protein 1 (AP-1) signaling pathway completely prevented the migration of keratinocytes, and also resulted in a diminished Mmp13 gene expression, suggesting that AP-1 might be essential in the AHL-induced migration. Taken together, these results imply that AHL is a promising candidate molecule to improve re-epithelialization through the induction of migration of keratinocytes. Further investigation is needed to clarify the mechanism of action and molecular pathway of AHL on the keratinocyte migration process.

The Asian-American E6 variant protein of human papillomavirus 16 alone is sufficient to promote immortalization, transformation, and migration of primary human foreskin keratinocytes

We examined how well the human papillomavirus (HPV) E6 oncogene can function in the absence of the E7 oncogene during the carcinogenic process in human keratinocytes using a common HPV variant strongly associated with cervical cancer: the Asian-American E6 variant (AAE6). This E6 variant is 20 times more frequently detected in cervical cancer than the prototype European E6 variant, as evidenced by independent epidemiological data. Using cell culture and cell-based functional assays, we assessed how this variant can perform crucial carcinogenesis steps compared to the prototype E6 variant. The ability to immortalize and transform primary human foreskin keratinocytes (PHFKs) to acquire resilient phenotypes and the ability to promote cell migration were evaluated. The immortalization capability was assayed based on population doublings, number of passages, surpassing mortality stages 1 and 2, human telomerase reverse transcriptase (hTERT) expression, and the ability to overcome G(1) arrest via p53 degradation. Transformation and migration efficiency were analyzed using a combination of functional cell-based assays. We observed that either AAE6 or prototype E6 proteins alone were sufficient to immortalize PHFKs, although AAE6 was more potent in doing so. The AAE6 variant protein alone pushed PHFKs through transformation and significantly increased their migration ability over that of the E6 prototype. Our findings are in line with epidemiological data that the AA variant of HPV16 confers an increased risk over the European prototype for cervical cancer, as evidenced by a superior immortalization, transformation, and metastatic potential.

[Hydroactive stage-adapted wound management]

The treatment of subacute and chronic wounds is not only a major medical challenge but because of demographic developments and the concurrent increase in predisposing diseases, such as diabetes mellitus and arterial occlusive disease is also a relevant socioeconomic challenge. The principle of modern, moist wound care can now be regarded as established. In daily practice there are nevertheless significant treatment problems which are, among other things due to the vast variety of products available. As evidence-based guidelines for the treatment of chronic wounds were until recently lacking and many question were left unanswered, standards of care represent an appropriate means of orientation. In addition to improved quality of care in this way costs can also be reduced. Furthermore, criteria can be illustrated by which the selection of appropriate wound dressings can be facilitated and established.

Modelling the interaction of keratinocytes and fibroblasts during normal and abnormal wound healing processes

The crosstalk between fibroblasts and keratinocytes is a vital component of the wound healing process, and involves the activity of a number of growth factors and cytokines. In this work, we develop a mathematical model of this crosstalk in order to elucidate the effects of these interactions on the regeneration of collagen in a wound that heals by second intention. We consider the role of four components that strongly affect this process: transforming growth factor-β, platelet-derived growth factor, interleukin-1 and keratinocyte growth factor. The impact of this network of interactions on the degradation of an initial fibrin clot, as well as its subsequent replacement by a matrix that is mainly composed of collagen, is described through an eight-component system of nonlinear partial differential equations. Numerical results, obtained in a two-dimensional domain, highlight key aspects of this multifarious process, such as re-epithelialization. The model is shown to reproduce many of the important features of normal wound healing. In addition, we use the model to simulate the treatment of two pathological cases: chronic hypoxia, which can lead to chronic wounds; and prolonged inflammation, which has been shown to lead to hypertrophic scarring. We find that our model predictions are qualitatively in agreement with previously reported observations and provide an alternative pathway for gaining insight into this complex biological process.

MMP-13 regulates growth of wound granulation tissue and modulates gene expression signatures involved in inflammation, proteolysis, and cell viability

Proteinases play a pivotal role in wound healing by regulating cell-matrix interactions and availability of bioactive molecules. The role of matrix metalloproteinase-13 (MMP-13) in granulation tissue growth was studied in subcutaneously implanted viscose cellulose sponge in MMP-13 knockout (Mmp13(-/-)) and wild type (WT) mice. The tissue samples were harvested at time points day 7, 14 and 21 and subjected to histological analysis and gene expression profiling. Granulation tissue growth was significantly reduced (42%) at day 21 in Mmp13(-/-) mice. Granulation tissue in Mmp13(-/-) mice showed delayed organization of myofibroblasts, increased microvascular density at day 14, and virtual absence of large vessels at day 21. Gene expression profiling identified differentially expressed genes in Mmp13(-/-) mouse granulation tissue involved in biological functions including inflammatory response, angiogenesis, cellular movement, cellular growth and proliferation and proteolysis. Among genes linked to angiogenesis, Adamts4 and Npy were significantly upregulated in early granulation tissue in Mmp13(-/-) mice, and a set of genes involved in leukocyte motility including Il6 were systematically downregulated at day 14. The expression of Pdgfd was downregulated in Mmp13(-/-) granulation tissue in all time points. The expression of matrix metalloproteinases Mmp2, Mmp3, Mmp9 was also significantly downregulated in granulation tissue of Mmp13(-/-) mice compared to WT mice. Mmp13(-/-) mouse skin fibroblasts displayed altered cell morphology and impaired ability to contract collagen gel and decreased production of MMP-2. These results provide evidence for an important role for MMP-13 in wound healing by coordinating cellular activities important in the growth and maturation of granulation tissue, including myofibroblast function, inflammation, angiogenesis, and proteolysis.

A comparison of epithelial-to-mesenchymal transition and re-epithelialization

Wound healing and cancer metastasis share a common starting point, namely, a change in the phenotype of some cells from stationary to motile. The term, epithelial-to-mesenchymal transition (EMT) describes the changes in molecular biology and cellular physiology that allow a cell to transition from a sedentary cell to a motile cell, a process that is relevant not only for cancer and regeneration, but also for normal development of multicellular organisms. The present review compares the similarities and differences in cellular response at the molecular level as tumor cells enter EMT or as keratinocytes begin the process of re-epithelialization of a wound. Looking toward clinical interventions that might modulate these processes, the mechanisms and outcomes of current and potential therapies are reviewed for both anti-cancer and pro-wound healing treatments related to the pathways that are central to EMT. Taken together, the comparison of re-epithelialization and tumor EMT serves as a starting point for the development of therapies that can selectively modulate different forms of EMT.

Enhanced keratinocyte proliferation and migration in co-culture with fibroblasts

Wound healing is primarily controlled by the proliferation and migration of keratinocytes and fibroblasts as well as the complex interactions between these two cell types. To investigate the interactions between keratinocytes and fibroblasts and the effects of direct cell-to-cell contact on the proliferation and migration of keratinocytes, keratinocytes and fibroblasts were stained with different fluorescence dyes and co-cultured with or without transwells. During the early stage (first 5 days) of the culture, the keratinocytes in contact with fibroblasts proliferated significantly faster than those not in contact with fibroblasts, but in the late stage (11(th) to 15(th) day), keratinocyte growth slowed down in all cultures unless EGF was added. In addition, keratinocyte migration was enhanced in co-cultures with fibroblasts in direct contact, but not in the transwells. Furthermore, the effects of the fibroblasts on keratinocyte migration and growth at early culture stage correlated with heparin-binding EGF-like growth factor (HB-EGF), IL-1α and TGF-β1 levels in the cultures where the cells were grown in direct contact. These effects were inhibited by anti-HB-EGF, anti-IL-1α and anti-TGF-β1 antibodies and anti-HB-EGF showed the greatest inhibition. Co-culture of keratinocytes and IL-1α and TGF-β1 siRNA-transfected fibroblasts exhibited a significant reduction in HB-EGF production and keratinocyte proliferation. These results suggest that contact with fibroblasts stimulates the migration and proliferation of keratinocytes during wound healing, and that HB-EGF plays a central role in this process and can be up-regulated by IL-1α and TGF-β1, which also regulate keratinocyte proliferation differently during the early and late stage.

Administration, distribution, metabolism and elimination of polymer therapeutics

Polymer conjugation is an efficient approach to improve the delivery of drugs and biological agents, both by protecting the body from the drug (by improving biodistribution and reducing toxicity) and by protecting the drug from the body (by preventing degradation and enhancing cellular uptake). This review discusses the journey that polymer therapeutics make through the body, following the ADME (absorption, distribution, metabolism, excretion) concept. The biological factors and delivery system parameters that influence each stage of the process will be described, with examples illustrating the different solutions to the challenges of drug delivery systems in vivo.

Role of matrix metaloproteases in idiopathic pulmonary fibrosis

Lung fibrosis is the final common pathway of a large variety of chronic lung disorders, named interstitial lung diseases. The most aggressive form is the idiopathic pulmonary fibrosis [IPF] characterized by alveolar epithelial cell injury/activation, expansion of the fibroblast/myofibroblast population, and the exaggerated accumulation of extracellular matrix [ECM] components which ultimately result in the destruction of the lung parenchyma. Several matrix metalloproteases [MMPs] are upregulated in the IPF lungs and have been shown to actively participate in the pathogenesis of the disease through extracellular matrix remodeling and basement membrane disruption. However, MMPs can also breakdown molecules that mediate cell-cell and cell-ECM interactions, and can activate growth factors and growth factor receptors indicating that they likely contribute to other local biopathological processes such as apoptosis, migration, proliferation and angiogenesis.

In vitro study of novel collagenase (XIAFLEX®) on Dupuytren's disease fibroblasts displays unique drug related properties

Dupuytren's disease (DD) is a benign, fibroproliferative disease of the palmar fascia, with excessive extracellular matrix (ECM) deposition and over-production of cytokines and growth factors, resulting in digital fixed flexion contractures limiting hand function and patient quality of life. Surgical fasciectomy is the gold standard treatment but is invasive and has associated morbidity without limiting disease recurrence. Injectable Collagenase Clostridium histolyticum (CCH)--Xiaflex®--is a novel, nonsurgical option with clinically proven in vivo reduction of DD contractures but with limited in vitro data demonstrating its cellular and molecular effects. The aim of this study was to delineate the effects of CCH on primary fibroblasts isolated from DD and non-DD anatomical sites (using RTCA, LDH, WST-1, FACS, qRT-PCR, ELISA and In-Cell Quantitative Western Blotting) to compare the efficacy of varying concentrations of Xiaflex® against a reagent grade Collagenase, Collagenase A. Results demonstrated that DD nodule and cord fibroblasts had greater proliferation than those from fat and skin. Xiaflex® exposure resulted in dose- and time-dependent inhibition of cellular spreading, attachment and proliferation, with cellular recovery after enzyme removal. Unlike Collagenase A, Xiaflex® did not cause apoptosis. Collagen expression patterns were significantly (p<0.05) different in DD fibroblasts across anatomical sites - the highest levels of collagen I and III were detected in DD nodule, with DD cord and fat fibroblasts demonstrating a smaller increase in both collagen expression relative to DD skin. Xiaflex® significantly (p<0.05) down-regulated ECM components, cytokines and growth factors in a dose-dependent manner. An in vitro scratch wound assay model demonstrated that, at low concentrations, Xiaflex® enabled a faster fibroblast reparatory migration into the wound, whereas, at high concentrations, this process was significantly (p<0.05) inhibited. This is the first report elucidating potential mechanisms of action of Xiaflex® on Dupuytren fibroblasts, offering a greater insight and a better understanding of its effect in DD.

Activation of pro-uPA is critical for initial escape from the primary tumor and hematogenous dissemination of human carcinoma cells

Urokinase-type plasminogen activator (uPA) and plasmin have long been implicated in cancer progression. However, the precise contributions of the uPA/plasmin system to specific steps involved in cancer cell dissemination have not been fully established. Herein, we have used a highly disseminating variant of the human PC-3 prostate carcinoma cell line, PC-hi/diss, as a prototype of aggressive carcinomas to investigate the mechanisms whereby pro-uPA activation and uPA-generated plasmin functionally contribute to specific stages of metastasis. The PC-hi/diss cells secrete and activate significant amounts of pro-uPA, leading to efficient generation of plasmin in solution and at the cell surface. In a mouse orthotopic xenograft model, treatment with the specific pro-uPA activation-blocking antibody mAb-112 significantly inhibited local invasion and distant metastasis of the PC-hi/diss cells. To mechanistically examine the uPA/plasmin-mediated aspects of tumor cell dissemination, the anti-pro-uPA mAb-112 and the potent serine protease inhibitor, aprotinin, were used in parallel in a number of in vivo assays modeling various rate-limiting steps in early metastatic spread. Our findings demonstrate that, by generating plasmin, activated tumor-derived uPA facilitates early stages of PC-hi/diss dissemination, specifically the escape from the primary tumor and tumor cell intravasation. Moreover, through a series of in vitro and in vivo analyses, we suggest that PC-hi/diss-invasive escape and dissemination may be enhanced by cleavage of stromal fibronectin by uPA-generated plasmin. Together, our findings point to inhibition of pro-uPA activation at the apex of the uPA/plasmin cascade as a therapy-valid approach to control onset of tumor escape and ensuing metastatic spread.