Serum levels of matrix metalloproteinases 1, 2, and 7, and their tissue inhibitors 1, 2, 3, and 4 in polytraumatized patients: Time trajectories, correlations, and their ability to predict mortality.

There has been limited research on assessing metalloproteinases (MMPs) 1, 2, and 7, as well as their tissue inhibitors (TIMPs) 1, 2, 3, and 4 in the context of polytrauma. These proteins play crucial roles in various physiological and pathological processes and could be a reliable tool in polytrauma care. We aimed to determine their clinical relevance. We assessed 24 blunt polytrauma survivors and 12 fatalities (mean age, 44.2 years, mean ISS, 45) who were directly admitted to our Level I trauma center and spent at least one night in the intensive care unit. We measured serum levels of the selected proteins on admission (day 0) and days 1, 3, 5, 7, and 10. The serum levels of the seven proteins varied considerably among individuals, resulting in similar median trend curves for TIMP1 and TIMP4 and for MMP1, MMP2, TIMP2, and TIMP3. We also found a significant interrelationship between the MMP2, TIMP2, and TIMP3 levels at the same measurement points. Furthermore, we calculated significant cross-correlations between MMP7 and MMP1, TIMP1 and MMP7, TIMP3 and MMP1, TIMP3 and MMP2, and TIMP4 and TIMP3 and an almost significant correlation between MMP7 and TIMP1 for a two-day-lag. The autocorrelation coefficient reached statistical significance for MMP1 and TIMP3. Finally, lower TIMP1 serum levels were associated with in-hospital mortality upon admission. The causal effects and interrelationships between selected proteins might provide new insights into the interactions of MMPs and TIMPs. Identifying the underlying causes might help develop personalized therapies for patients with multiple injuries. Administering recombinant TIMP1 or increasing endogenous production could improve outcomes for those with multiple injuries. However, before justifying further investigations into basic research and clinical relevance, our findings must be validated in a multicenter study using independent cohorts to account for clinical and biological variability.

Matrix Metalloproteinases in the Periodontium-Vital in Tissue Turnover and Unfortunate in Periodontitis.

The extracellular matrix (ECM) is a complex non-cellular three-dimensional macromolecular network present within all tissues and organs, forming the foundation on which cells sit, and composed of proteins (such as collagen), glycosaminoglycans, proteoglycans, minerals, and water. The ECM provides a fundamental framework for the cellular constituents of tissue and biochemical support to surrounding cells. The ECM is a highly dynamic structure that is constantly being remodeled. Matrix metalloproteinases (MMPs) are among the most important proteolytic enzymes of the ECM and are capable of degrading all ECM molecules. MMPs play a relevant role in physiological as well as pathological processes; MMPs participate in embryogenesis, morphogenesis, wound healing, and tissue remodeling, and therefore, their impaired activity may result in several problems. MMP activity is also associated with chronic inflammation, tissue breakdown, fibrosis, and cancer invasion and metastasis. The periodontium is a unique anatomical site, composed of a variety of connective tissues, created by the ECM. During periodontitis, a chronic inflammation affecting the periodontium, increased presence and activity of MMPs is observed, resulting in irreversible losses of periodontal tissues. MMP expression and activity may be controlled in various ways, one of which is the inhibition of their activity by an endogenous group of tissue inhibitors of metalloproteinases (TIMPs), as well as reversion-inducing cysteine-rich protein with Kazal motifs (RECK).

Simultaneous Visualization and Depletion of Peroxynitrite by a Simple Aggregation-Induced Emission Nanoprobe for Preventing Breast Cancer Metastasis after Surgery.

Inflammation has been confirmed to be closely related to the development of tumors, while peroxynitrite (ONOO-) is one of the most powerful oxidative pro-inflammatory factors. Although ONOO- can kill bacteria through oxidation, it will activate matrix metalloproteinases (MMPs), accelerate the degradation of the extracellular matrix (ECM), and subsequently lead to the activation and release of other tumor promotion factors existing in the ECM, promoting tumor metastasis and invasion. Herein, we report a simple aggregation-induced emission (AIE) nanoprobe (NP), TPE-4NMB, that can simultaneously visualize and deplete ONOO-. The probe can light up the endogenous and exogenous ONOO- in cells and selectively inhibit the proliferation and migration of 4T1 cells by inducing an intracellular redox homeostasis imbalance through ONOO- depletion. After being modified with DSPE-PEG2000, the TPE-4NMB NPs can be used to image ONOO- induced by various models in vivo; especially, it can monitor the dynamic changes of ONOO- level in the residual tumor after surgery, which can provide evidence for clarifying the association between surgery, ONOO-, and cancer metastasis. Excitingly, inhibited tumor volume growth and decreased counts of lung metastases were observed in the TPE-4NMB NPs group, which can be attributed to the downregulated expression of MMP-9 and transforming growth factor-ß (TGF-ß), increased cell apoptosis, and inhibited epithelial-mesenchymal transition (EMT) mediated by ONOO-. The results will provide new evidence for clarifying the relationship between surgery, ONOO-, and tumor metastasis and serve as a new intervention strategy for preventing tumor metastasis after tumor resection.

Intracellular Zn2+ promotes extracellular matrix remodeling in dexamethasone-treated trabecular meshwork.

Given the widespread application of glucocorticoids in ophthalmology, the associated elevation of intraocular pressure (IOP) has long been a vexing concern for clinicians, yet the underlying mechanisms remain inconclusive. Much of the discussion focuses on the extracellular matrix (ECM) of trabecular meshwork (TM). It is widely agreed that glucocorticoids impact the expression of matrix metalloproteinases (MMPs), leading to ECM deposition. Since Zn2+ is vital for MMPs, we explored its role in ECM alterations induced by dexamethasone (DEX). Our study revealed that in human TM cells treated with DEX, the level of intracellular Zn2+ significantly decreased, accompanied by impaired extracellular Zn2+ uptake. This correlated with changes in several Zrt-, Irt-related proteins (ZIPs) and metallothionein. ZIP8 knockdown impaired extracellular Zn2+ uptake, but Zn2+ chelation did not affect ZIP8 expression. Resembling DEX's effects, chelation of Zn2+ decreased MMP2 expression, increased the deposition of ECM proteins, and induced structural disarray of ECM. Conversely, supplementation of exogenous Zn2+ in DEX-treated cells ameliorated these outcomes. Notably, dietary zinc supplementation in mice significantly reduced DEX-induced IOP elevation and collagen content in TM, thereby rescuing the visual function of the mice. These findings underscore zinc's pivotal role in ECM regulation, providing a novel perspective on the pathogenesis of glaucoma.NEW & NOTEWORTHY Our study explores zinc's pivotal role in mitigating extracellular matrix dysregulation in the trabecular meshwork and glucocorticoid-induced ocular hypertension. We found that in human trabecular meshwork cells treated with dexamethasone, intracellular Zn2+ significantly decreased, accompanied by impaired extracellular Zn2+ uptake. Zinc supplementation rescues visual function by modulating extracellular matrix proteins and lowering intraocular pressure, offering a direction for further exploration in glaucoma management.

The mechanistic role of curcumin on matrix metalloproteinases in osteoarthritis.

A systematic mechanistic review was performed to determine mechanistic evidence for curcumin on pro-inflammatory matrix metalloproteinases and Osteoarthritis to understand the underlying pathophysiology, and to evaluate available human intervention evidence to inform clinical decision making. The systematic literature search was performed in 3 tranches (reviews, mechanistic, intervention studies) using PubMed, with no date limitations and using specific search terms. 65 out of 393 screened papers were accepted based on detailed inclusion and exclusion criteria. The mechanistic search was divided into three searches and the intervention searches were subdivided into four searches. Curcumin demonstrated significant inhibition of matrix metalloproteinases linked to cartilage degradation in Osteoarthritis through reduced activation of the nuclear factor kappa-B signaling pathway via suppressing phosphorylation of Iκßa and p65 nuclear translocation. Mechanistic evidence implicated matrix metalloproteinases in Osteoarthritis by decreasing Type II collagen, leading to cartilage damage. As a potential nutritional intervention for Osteoarthritis, curcumin could reduce inflammatory markers and improve pain and function scores. The evidence indicates most formulations of turmeric extract and curcumin extract, bio-enhanced and non-bio-enhanced, are effective at improving inflammatory markers and pain and function to a greater or lesser extent. Due to the high heterogeneity of the formulations, dosage, and duration of the studies, further research is needed to fully understand curcumin's potential as a promising non-pharmaceutical intervention for Osteoarthritis. This mechanism review identifies a gap in current research for the mechanism by which Type II collagen is mediated.

Bone protective effect of sinomenine against monosodium iodoacetate induced knee and hip injury in rat model: an inflammatory pathway.

PURPOSE: Osteoarthritis (OA) is a degenerative joint disease which is categorized via destruction of joint cartilage and it also affects the various joints, especially knees and hips. Sinomenine active phytoconstituents isolated from the stem of Sinomenium acutum and already proof anti-inflammatory effect against the arthritis model of rodent. In this experimental protocol, we scrutinized the anti-osteoarthritis effect of sinomenine against monosodium iodoacetate (MIA) induced OA in rats. METHODS: MIA (3 mg/50 µL) was used for inducing the OA in the rats, and rats received the oral administration of sinomenine (2.5, 5 and 7.5 mg/kg body weight) up to the end of the experimental study (four weeks). The body and organs weight were estimated. Aggrecan, C-terminal cross-linked telopeptide of type II collagen (CTX-II), glycosaminoglycans (GCGs), monocyte chemoattractant protein-1 (MCP-1), Interferon gamma (IFN-γ), antioxidant, inflammatory cytokines, inflammatory mediators and matrix metalloproteinases (MMP) were analyzed. RESULTS: Sinomenine significantly (P < 0.001) boosted the body weight and reduced the heart weight, but the weight of spleen and kidney remain unchanged. Sinomenine significantly (P < 0.001) reduced the level of nitric oxide, MCP-1 and improved the level of aggrecan, IFN-γ and GCGs. Sinomenine remarkably upregulated the level of glutathione, superoxide dismutase and suppressed the level of malonaldehyde. It effectually modulated the level of inflammatory cytokines and inflammatory mediators and significantly (P < 0.001) reduced the level of MMPs, like MMP-1, 2, 3, 9 and 13. CONCLUSIONS: Sinomenine is a beneficial active agent for the treatment of OA disease.

Epidermal Growth Factor Suppresses the Development of GABAergic Neurons Via the Modulation of Perineuronal Net Formation in the Neocortex of Developing Rodent Brains.

Previously, we reported that epidermal growth factor (EGF) suppresses GABAergic neuronal development in the rodent cortex. Parvalbumin-positive GABAergic neurons (PV neurons) have a unique extracellular structure, perineuronal nets (PNNs). PNNs are formed during the development of PV neurons and are mainly formed from chondroitin sulfate (CS) proteoglycans (CSPGs). We examined the effect of EGF on CSPG production and PNN formation as a potential molecular mechanism for the inhibition of inhibiting GABAergic neuronal development by EGF. In EGF-overexpressing transgenic (EGF-Tg) mice, the number of PNN-positive PV neurons was decreased in the cortex compared with that in wild-type mice, as in our previous report. The amount of CS and neurocan was also lower in the cortex of EGF-Tg mice, with a similar decrease observed in EGF-treated cultured cortical neurons. PD153035, an EGF receptor (ErbB1) kinase inhibitor, prevented those mentioned above excess EGF-induced reduction in PNN. We explored the molecular mechanism underlying the effect of EGF on PNNs using fluorescent substrates for matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs). EGF increased the enzyme activity of MMPs and ADAMs in cultured neurons. These enzyme activities were also increased in the EGF-Tg mice cortex. GM6001, a broad inhibitor of MMPs and ADAMs, also blocked EGF-induced PNN reductions. Therefore, EGF/EGF receptor signals may regulate PNN formation in the developing cortex.

Inhibition of HOXD11 promotes cartilage degradation and induces osteoarthritis development.

The 5'-HOXD genes are important for chondrogenesis in vertebrates, but their roles in osteoarthritis (OA) are still ambiguous. In our study, 5'-HOXD genes involvement contributing to cartilage degradation and OA was investigated. In bioinformatics analysis of 5'-HOXD genes, we obtained the GSE169077 data set related to OA in the GEO and analyzed DEGs using the GEO2R tool attached to the GEO. Then, we screened the mRNA levels of 5'-HOXD genes by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). We discovered that OA chondrocyte proliferation was inhibited, and apoptosis was increased. Moreover, it was discovered that SOX9 and COL2A1 were downregulated at mRNA and protein levels, while matrix metalloproteinases (MMPs) and a disintegrin-like and metalloproteinase with thrombospondin motifs (ADAMTSs) were upregulated. According to the results of differentially expressed genes (DEGs) and qRT-PCR, we evaluated the protein level of HOXD11 and found that the expression of HOXD11 was downregulated, reversed to MMPs and ADAMTSs but consistent with the cartilage-specific factors, SOX9 and COL2A1. In the lentivirus transfection experiments, HOXD11 overexpression reversed the effects in OA chondrocytes. In human OA articular cartilage, aberrant subchondral bone was formed in hematoxylin-eosin (H&E) and Safranin O and fast green (SOFG) staining results. Furthermore, according to immunohistochemistry findings, SOX9 and HOXD11 expression was inhibited. The results of this study established that HOXD11 was downregulated in OA cartilage and that overexpression of HOXD11 could prevent cartilage degradation in OA.

A Model for Membrane Degradation Using a Gelatin Invadopodia Assay.

One of the most crucial and lethal characteristics of solid tumors is represented by the increased ability of cancer cells to migrate and invade other organs during the so-called metastatic spread. This is allowed thanks to the production of matrix metalloproteinases (MMPs), enzymes capable of degrading a type of collagen abundant in the basal membrane separating the epithelial tissue from the connective one. In this work, we employ a synergistic experimental and mathematical modelling approach to explore the invasion process of tumor cells. A mathematical model composed of reaction-diffusion equations describing the evolution of the tumor cells density on a gelatin substrate, MMPs enzymes concentration and the degradation of the gelatin is proposed. This is completed with a calibration strategy. We perform a sensitivity analysis and explore a parameter estimation technique both on synthetic and experimental data in order to find the optimal parameters that describe the in vitro experiments. A comparison between numerical and experimental solutions ends the work.

In vitro collagen biomarkers in mechanically stimulated human tendon cells: a systematic review.

OBJECTIVE: The aim of this study was to comprehensively examine and summarize the available in vitro evidence regarding the relationship between mechanical stimulation and biomarkers of collagen synthesis in human-derived tendon cells. METHODS: Systematic review with narrative analyses and risk of bias assessment guided by the Health Assessment and Translation tool. The electronic databases MEDLINE (Ovid), EMBASE (Ovid), CENTRAL (Ovid) and COMPENDEX (Engineering Village) were systematically searched from inception to 3 August 2023. Inclusion criteria encompassed English language, original experimental, or quasi-experimental in vitro publications that subjected human tendon cells to mechanical stimulation, with collagen synthesis (total collagen, type I, III, V, XI, XII, and XIV) and related biomarkers (matrix metalloproteinases, transforming growth factor ß, scleraxis, basic fibroblast growth factor) as outcomes. RESULTS: Twenty-one publications were included. A pervasive definite high risk of bias was evident in all included studies. Owing to incomplete outcome reporting and heterogeneity in mechanical stimulation protocols, planned meta-analyses were unfeasible. Reviewed data suggested that human tendon cells respond to mechanical stimulation with increased synthesis of collagen (e.g., COL1A1, procollagen, total soluble collagen, etc.), scleraxis and several matrix metalloproteinases. Results also indicate that mechanical stimulation dose magnitude may influence synthesis in several biomarkers. CONCLUSIONS: A limited number of studies, unfortunately characterized by a definite high risk of bias, suggest that in vitro mechanical stimulation primarily increases type I collagen synthesis by human tendon cells. Findings from this systematic review provide researchers and clinicians with biological evidence concerning the possible beneficial influence of exercise and loading on cellular-level tendon adaptation.

Engineered liposomes targeting hepatic stellate cells overcome pathological barriers and reverse liver fibrosis.

Dual pathological barriers, including capillarized liver sinusoidal endothelial cells (LSECs) and deposited extracellular matrix (ECM), result in insufficient drug delivery, significantly compromising the anti-fibrosis efficacy. Additionally, excessive reactive oxygen species (ROS) in the hepatic microenvironment are crucial factors contributing to the progression of liver fibrosis. Hence, hyaluronic acid (HA) modified liposomes co-delivering all-trans retinoic acid (RA) and L-arginine (L-arg) were constructed to reverse hepatic fibrosis. By exhibiting exceptional responsiveness to the fibrotic microenvironment, our cleverly constructed liposomes efficiently disrupted the hepatic sinus pathological barrier, leading to enhanced accumulation of liposomes in activated hepatic stellate cells (HSCs) and subsequent induction of HSCs quiescence. Specially, excessive ROS in liver fibrosis promotes the conversion of loaded L-arg to nitric oxide (NO). The ensuing NO serves to reestablish the fenestrae structure of capillarized LSECs, thereby augmenting the likelihood of liposomes reaching the hepatic sinus space. Furthermore, subsequent oxidation of NO by ROS into peroxynitrite activates pro-matrix metalloproteinases into matrix metalloproteinases, which further disrupts the deposited ECM barrier. Consequently, this NO-induced cascade process greatly amplifies the accumulation of liposomes within activated HSCs. More importantly, the released RA could induce quiescence of activated HSCs by significantly downregulating the expression of myosin light chain-2, thereby effectively mitigating excessive collagen synthesis and ultimately leading to the reversal of liver fibrosis. Overall, this integrated systemic strategy has taken a significant step forward in advancing the treatment of liver fibrosis.

Matrix metalloproteinases as attractive therapeutic targets for chronic pain: A narrative review.

Chronic pain constitutes an abnormal pain state that detrimentally affects the quality of life, daily activities, occupational performance, and stability of mood. Despite the prevalence of chronic pain, effective drugs with potent abirritation and minimal side effects remain elusive. Substantial studies have revealed aberrant activation of the matrix metalloproteinases (MMPs) in multiple chronic pain models. Additionally, emerging evidence has demonstrated that the downregulation of MMPs can alleviate chronic pain in diverse animal models, underscoring the unique and crucial role of MMPs in different stages and types of chronic pain. This review delves into the mechanistic insights and roles of MMPs in modulating chronic pain. The aberrant activation of MMPs has been linked to neuropathic pain through mechanisms involving myelin abnormalities in peripheral nerve and spinal dorsal horn (SDH), hyperexcitability of dorsal root ganglion (DRG) neurons, activation of N-methyl-d-aspartate receptors (NMDAR) and Ca2+-dependent signals, glial cell activation, and proinflammatory cytokines release. Different MMPs also contribute significantly to inflammatory pain and cancer pain. Furthermore, we summarized the substantial therapeutic potential of MMP pharmacological inhibitors across different types of chronic pain. Overall, our findings underscore the promising therapeutic prospects of MMPs targeting for managing chronic pain.

Unveiling breast cancer metastasis through an advanced X-ray imaging approach.

Breast cancer is a significant global health burden, causing a substantial number of deaths. Systemic metastatic tumour cell dissemination is a major cause of poor outcomes. Understanding the mechanisms underlying metastasis is crucial for effective interventions. Changes in the extracellular matrix play a pivotal role in breast cancer metastasis. In this work, we present an advanced multimodal X-ray computed tomography, by combining Small-angle X-ray Scattering Tensor Tomography (SAXS-TT) and X-ray Fluorescence Computed Tomography (XRF-CT). This approach likely brings out valuable information about the breast cancer metastasis cascade. Initial results from its application on a breast cancer specimen reveal the collective influence of key molecules in the metastatic mechanism, identifying a strong correlation between zinc accumulation (associated with matrix metalloproteinases MMPs) and highly oriented collagen. MMPs trigger collagen alignment, facilitating breast cancer cell intravasation, while iron accumulation, linked to angiogenesis and vascular endothelial growth factor VEGF, supports cell proliferation and metastasis. Therefore, these findings highlight the potential of the advanced multimodal X-ray computed tomography approach and pave the way for in-depth investigation of breast cancer metastasis, which may guide the development of novel therapeutic approaches and enable personalised treatment strategies, ultimately improving patient outcomes in breast cancer management.

The TIMP protein family: diverse roles in pathophysiology.

The tissue inhibitors of matrix metalloproteinases (TIMPs) are a family of four matrisome proteins classically defined by their roles as the primary endogenous inhibitors of metalloproteinases (MPs). Their functions however are not limited to MP inhibition, with each family member harboring numerous MP-independent biological functions that play key roles in processes such as inflammation and apoptosis. Because of these multifaceted functions, TIMPs have been cited in diverse pathophysiological contexts. Herein, we provide a comprehensive overview of the MP-dependent and -independent roles of TIMPs across a range of pathological conditions. The potential therapeutic and biomarker applications of TIMPs in these disease contexts are also considered, highlighting the biomedical promise of this complex and often misunderstood protein family.

The role of matrix metalloproteinase 9 in fibrosis diseases and its molecular mechanisms.

Fibrosis is a process of tissue repair that results in the slow creation of scar tissue to replace healthy tissue and can affect any tissue or organ. Its primary feature is the massive deposition of extracellular matrix (mainly collagen), eventually leading to tissue dysfunction and organ failure. The progression of fibrotic diseases has put a significant strain on global health and the economy, and as a result, there is an urgent need to find some new therapies. Previous studies have identified that inflammation, oxidative stress, some cytokines, and remodeling play a crucial role in fibrotic diseases and are essential avenues for treating fibrotic diseases. Among them, matrix metalloproteinases (MMPs) are considered the main targets for the treatment of fibrotic diseases since they are the primary driver involved in ECM degradation, and tissue inhibitors of metalloproteinases (TIMPs) are natural endogenous inhibitors of MMPs. Through previous studies, we found that MMP-9 is an essential target for treating fibrotic diseases. However, it is worth noting that MMP-9 plays a bidirectional regulatory role in different fibrotic diseases or different stages of the same fibrotic disease. Previously identified MMP-9 inhibitors, such as pirfenidone and nintedanib, suffer from some rather pronounced side effects, and therefore, there is an urgent need to investigate new drugs. In this review, we explore the mechanism of action and signaling pathways of MMP-9 in different tissues and organs, hoping to provide some ideas for developing safer and more effective biologics.

Discovery of matrix metalloproteinase inhibitors as anti-skin photoaging agents.

Photodamage is the result of prolonged exposure of the skin to sunlight. This exposure causes an overexpression of matrix metalloproteinases (MMPs), leading to the abnormal degradation of collagen in the skin tissue and resulting in skin aging and damage. This review presents a detailed overview of MMPs as a potential target for addressing skin aging. Specifically, we elucidated the precise mechanisms by which MMP inhibitors exert their anti-photoaging effects. Furthermore, we comprehensively analyzed the current research progress on MMP inhibitors that demonstrate significant inhibitory activity against MMPs and anti-skin photoaging effects. The review also provides insights into the structure-activity relationships of these inhibitors. Our objective in conducting this review is to provide valuable practical information to researchers engaged in investigations on anti-skin photoaging.

Human apical-out nasal organoids reveal an essential role of matrix metalloproteinases in airway epithelial differentiation.

Extracellular matrix (ECM) assembly/disassembly is a critical regulator for airway epithelial development and remodeling. Airway organoid is widely used in respiratory research, yet there is limited study to indicate the roles and mechanisms of ECM organization in epithelial growth and differentiation by using in vitro organoid system. Moreover, most of current Matrigel-based airway organoids are in basal-out orientation where accessing the apical surface is challenging. We present a human apical-out airway organoid using a biochemically defined hybrid hydrogel system. During human nasal epithelial progenitor cells (hNEPCs) differentiation, the gel gradually degrade, leading to the organoid apical surfaces facing outward. The expression and activity of ECM-degrading enzymes, matrix metalloproteinases (MMP7, MMP9, MMP10 and MMP13) increases during organoid differentiation, where inhibition of MMPs significantly suppresses the normal ciliation, resulting in increased goblet cell proportion. Moreover, a decrease of MMPs is found in goblet cell hyperplastic epithelium in inflammatory mucosa. This system reveals essential roles of epithelial-derived MMPs on epithelial cell fate determination, and provides an applicable platform enabling further study for ECM in regulating airway development in health and diseases.

Matrix metalloproteinases in intestinal fibrosis.

Intestinal fibrosis is a common complication in patients with inflammatory bowel disease [IBD], in particular Crohn's disease [CD]. Unfortunately, at present intestinal fibrosis is not yet preventable, and cannot be treated by interventions other than surgical removal. Intestinal fibrosis is characterized by excessive accumulation of extracellular matrix [ECM], which is caused by activated fibroblasts and smooth muscle cells. Accumulation of ECM results from an imbalanced production and degradation of ECM. ECM degradation is mainly performed by matrix metalloproteinases [MMPs], enzymes that are counteracted by tissue inhibitors of MMPs [TIMPs]. In IBD patients, MMP activity [together with other protease activities] is increased. At the same time, CD patients have a generally lower MMP activity compared to ulcerative colitis patients, who usually do not develop intestinal strictures or fibrosis. The exact regulation and role[s] of these MMPs in fibrosis are far from understood. Here, we review the current literature about ECM remodelling by MMPs in intestinal fibrosis and their potential role as biomarkers for disease progression or druggable targets.

In vitro dose-dependent effects of matrix metalloproteinases on ECM hydrogel biodegradation.

Matrix metalloproteinases (MMPs) cause proteolysis of extracellular matrix (ECM) in tissues affected by stroke. However, little is known about how MMPs degrade ECM hydrogels implanted into stroke cavities to regenerate lost tissue. To establish a structure-function relationship between different doses of individual MMPs and isolate their effects in a controlled setting, an in vitro degradation assay quantified retained urinary bladder matrix (UBM) hydrogel mass as a measure of degradation across time. A rheological characterization indicated that lower ECM concentrations (<4 mg/mL) did not cure completely at 37 °C and had a high fraction of mobile proteins that were easily washed-out. Hydrolysis by dH2O caused a steady 2 % daily decrease in hydrogel mass over 14 days. An acceleration of degradation to 6 % occurred with phosphate buffered saline and artificial cerebrospinal fluid. MMPs induced a dose-dependent increase and within 14 days almost completely (>95 %) degraded the hydrogel. MMP-9 exerted the most significant biodegradation, compared to MMP-3 and -2. To model the in vivo exposure of hydrogel to MMPs, mixtures of MMP-2, -3, and -9, present in the cavity at 14-, 28-, or 90-days post-stroke, revealed that 14- and 28-days mixtures achieved an equivalent biodegradation, but a 90-days mixture exhibited a slower degradation. These results revealed that hydrolysis, in addition to proteolysis, exerts a major influence on the degradation of hydrogels. Understanding the mechanisms of ECM hydrogel biodegradation is essential to determine the therapeutic window for bioscaffold implantation after a stroke, and they are also key to determine optimal degradation kinetics to support tissue regeneration. STATEMENT OF SIGNIFICANCE: After implantation into a stroke cavity, extracellular matrix (ECM) hydrogel promotes tissue regeneration through the degradation of the bioscaffold. However, the process of degradation of an ECM hydrogel remains poorly understood. We here demonstrated in vitro under highly controlled conditions that hydrogel degradation is very dependent on its protein concentration. Lower protein concentration hydrogels were weaker in rheological measurements and particularly susceptible to hydrolysis. The proteolytic degradation of tissue ECM after a stroke is caused by matrix metalloproteinases (MMPs). A dose-dependent MMP-driven biodegradation of ECM hydrogel exceeded the effects of hydrolysis. These results highlight the importance of in vitro testing of putative causes of degradation to gain a better understanding of how these factors affect in vivo biodegradation.

Mapping the Binding Sites of MMPs on Types II and III Collagens Using Triple-Helical Peptide Toolkits.

Libraries of triple-helical collagen-like peptides (Collagen Toolkits) have helped to define collagens II and III binding specificities of numerous collagen-binding proteins. Here I describe a simple solid-phase binding assay utilizing a biotin-streptavidin system to screen the Collagen Toolkits for binding of two distinct matrix metalloproteinases (MMPs) implicated in cancer: the collagenolytic MMP1 (collagenase 1) and the non-collagenolytic MMP3 (stromelysin 1). The screening revealed markedly disparate binding footprints of these MMPs on collagens II and III, in line with their distinct biological activities. Analogous screening of other potentially collagen-binding proteases may shed light on their inherent tissue retention capabilities and their pro- or anti-metastatic potential.