Role of Matrix Metalloproteinases in Musculoskeletal Diseases

ECM-binding properties of extracellular vesicles: advanced delivery strategies for therapeutic applications in bone and joint diseases

Extracellular vesicles (EVs) and the extracellular matrix (ECM) are essential in maintaining bone and joint health by facilitating intercellular communication, regulating tissue processes and providing structural support. EVs with a large surface area carry diverse biomolecules to steer the function of cells in their surroundings. To understand how EVs localize to specific sites, we here review the available knowledge on EV surface biomolecules and their interactions with ECM components that are crucial for regulating bone remodeling, cartilage maintenance, and immune responses, playing roles in both tissue homeostasis and pathological conditions, such as arthritis and osteoporosis. More importantly, using analyses of animal experimental data, we illustrate the effect of ECM-based biomaterials (e.g. hydrogels, decellularized matrices, and ECM-mimetic scaffolds) as carriers for EVs toward effective EV delivery in regenerative and immunomodulatory therapies in bone and joint tissue. These biomaterials enable sustained release and targeted delivery of EVs, promoting bone and cartilage regeneration. The insights of this review can be utilized to advance the development of cutting-edge therapies for skeletal tissue regeneration and disease management.

In Vitro Bioactivity Evaluation of IL-4 and SDF-1 Mimicking Peptides Engineered to Enhance Skeletal Muscle Reconstruction

Skeletal muscle regeneration depends on satellite cells, which, in response to injury, activate, proliferate, and reconstruct damaged tissue. However, under certain conditions, such as large injuries or myopathies, this process may not be properly executed, and muscle function may be affected. Thus, pro-regenerative actions, such as the use of various factors or cells, are widely tested as a tool to improve muscle regeneration. In the current study, we designed peptides derived from the IL-4 and SDF-1 proteins, namely IL-4-X, IL-4-Y, SDF-1-X, and SDF-1-Y. We showed that these peptides can bind to appropriate receptors and can adopt proper structure in solution. Importantly, we documented, using in vitro culture, that they do not negatively affect the cells that are present and active in skeletal muscles, such as myoblasts and fibroblasts, bone marrow stromal cells, as well as induced pluripotent stem cells, which can serve as a source of myoblasts. The presence of peptides did not affect cell proliferation compared to untreated cells. In vitro culture and differentiation protocols documented that selected IL-4 and SDF-1 peptides increased cell migration and inhibited undesirable adipogenic differentiation. Thus, we proved that these peptides are safe to use in in vivo studies aimed at improving skeletal muscle regeneration.

ADAMTS4 Reduction Contributes to Extracellular Matrix Deposition and Impaired Myogenesis in the Skeletal Muscle of Cigarette Smoke-Exposed Mice

Background: The extracellular matrix (ECM) plays a critical role in the proper regeneration of skeletal muscle. ECM remodeling has been reported in the skeletal muscle of chronic obstructive pulmonary disease (COPD), while the mechanisms remain poorly understood. Methods: In this study, we examined the dynamic interplay between ECM components and ECM enzymes in COPD skeletal muscle and cigarette smoke (CS) extract-treated C2C12 cells. C2C12 cells were further used to evaluate the role of a disintegrin and metalloproteinase with thrombospondin motif 4 (ADAMTS4) in ECM remodeling and myogenesis. Results: Chronic CS exposure induced the development of COPD and comorbid sarcopenia in C57BL/6J mice. Muscle fibrosis was observed in the gastrocnemius muscle of CS-exposed mice, accompanied by an upregulation of protein expression but a downregulation of mRNA levels of fibronectin and versican. We found that the discrepancy of mRNA and protein expression was attributed to the aberrant secretion of some ECM enzymes belonging to matrix metalloproteinases and ADAMTS proteases, especially ADAMTS4. CS exposure reduced ADAMTS4 expression in gastrocnemius muscles and C2C12 cells, and Adamts4 knockdown induced fibronectin and versican accumulation and impeded myogenic process. Conclusions: Considering that recent studies have indicated an impaired skeletal muscle regeneration in COPD, we suggested that the restrained production of ADAMTS4 in response to CS could be involved in the damaged muscle regeneration through regulating skeletal muscle ECM in COPD. Targeting ECM enzymes may benefit the rehabilitation of COPD-related sarcopenia.

Unlocking the therapeutic potential of WISP-1: A comprehensive exploration of its role in age-related musculoskeletal disorders

As the global population ages, the incidence of age-related musculoskeletal diseases continues to increase, driven by numerous complex and poorly understood factors. WNT-1 inducible secreted protein 1 (WISP-1), a secreted matrix protein, plays a critical role in the growth and development of the musculoskeletal system, including chondrogenesis, osteogenesis, and myogenesis. Numerous in vivo and in vitro studies have demonstrated that WISP-1 is significantly upregulated in age-related musculoskeletal conditions, such as osteoarthritis, osteoporosis, and sarcopenia, suggesting its involvement in the pathogenesis of these diseases. Regulating WISP-1 expression holds promise as a therapeutic strategy for improving musculoskeletal function, potentially offering new avenues for treating age-related musculoskeletal diseases in clinical practice. This review highlights the signaling pathways associated with WISP-1, its physiological roles within the musculoskeletal system, and its therapeutic potential in treating age-related musculoskeletal disorders.

Fibrillar Hydrogel Inducing Cell Mechanotransduction for Tissue Engineering

One of the key strategies for tissue engineering is to design multifunctional bioinks that balance printability with cytocompatibility. Here, we describe fibrillar hydrogels produced by Schiff base formation between B-type gelatin and oxidized sodium alginate, followed by the incorporation of type I collagen, yielding a new gel (MyoColl). The resulting hydrogel exhibits a temperature- and mass-ratio-dependent sol-gel transition, showing variability of hydrogel properties depending on the component ratio. MyoColl composition provides a convenient platform for biofabrication in terms of shear thinning, yielding, Young's modulus, and shape accuracy. Metabolic activity tests and fluorescent microscopy of 2D hydrogel-based mouse C2C12 myoblast cell culture show significant cytocompatibility of the developed carriers. In addition, primary signs of cell mechanotransduction and myofilament formation of 3D printed MyoColl-based cell cultures were detected and described. Due to these promising results, the described hydrogel composition has shown itself as a convenient platform for muscle tissue engineering.

Identification of pancreatic cancer-specific protease substrates for protease-dependent targeted delivery

Pancreatic ductal adenocarcinoma (PDAC) presents significant challenges due to the inadequacy of existing chemotherapeutics, which often result in toxicity-dependent dose limitations and premature cessation of therapy. Targeted delivery of therapeutic molecules offers a promising solution. Given that PDAC is marked by a desmoplastic reaction with extensive aberrant protease activity, protease-dependent targeted delivery could minimize off-target toxicities and is of increasing interest. The efficacy of targeted delivery hinges on the specificity of the substrates used; insufficient specificity can lead to off-target effects, reducing the advantage over non-targeted methods. Here, we employ an unbiased library approach to screen over 7 million peptide substrates for proteolytic cleavage by PDAC cell lysates, identifying 37 substrates enriched by at least 500-fold after three rounds of selection. As systemically administered targeted delivery depends on the absence of substrate cleavage in circulation, the peptide library was also screened against whole blood lysates, and enriched substrates were removed from the PDAC-enriched dataset to obtain PDAC-specific substrates. In vitro validation using FRET-peptides showed that 13 of the selected 15 substrates are cleaved by a panel of PDAC cell line lysates. Moreover, evaluation against healthy murine organ and human blood lysates to assess off-target cleavage revealed that the identified substrates are indeed PDAC-specific and that several substrates may be superior with respect to PDAC specificity over the CAPN2-responsive substrate, which has recently shown preclinical potential in targeted therapy, but future animal models should address the potential superiority. Overall, we thus identified substrates with high selectivity and sensitivity for PDAC that could be employed in protease-dependent targeted therapies.

Adaptive responses of skeletal muscle to calcaneal tendon partial injury in rats: insights into remodeling and plasticity

BACKGROUND

Skeletal muscle is a highly adaptive tissue, capable of responding to different physiological and functional demands, even in situations that may cause instability.

OBJECTIVES

To evaluate how partial calcaneal tendon (CT) injuries affect the remodeling and plasticity of the gastrocnemius muscle over time.

METHODS AND RESULTS

The study was carried out with Wistar rats randomly divided into five groups. The control group comprised animals not subjected to partial CT damage. The remaining four groups were subjected to partial CT damage and were further categorized based on the time of euthanasia: 3, 14, 28, and 55 days after injury. The gastrocnemius muscle was collected and used for gene expression analysis, zymography, flow cytometry, and morphology. The calcaneal tendon was analyzed only to verify the presence of the partial injury.

RESULTS

The impact of partial CT injury on the gastrocnemius homeostasis, particularly on gene expression, was more pronounced in the 3-day group compared to the other groups, especially the control group. Cytokine profile and morphologic alterations occurred in the 55 days group when compared to the other groups.

CONCLUSIONS

The data reported here suggest that partial injury can negatively affect intracellular signaling and degradation pathways, disturbing the muscular extracellular matrix regulatory mechanisms and communication with the tendon. However, skeletal muscle seems to mitigate these harmful effects in comparison with lesions that affect muscle and tendon.

Emerging Targets and Treatments for Sarcopenia: A Narrative Review

BACKGROUND

Sarcopenia is characterized by the progressive loss of skeletal muscle mass, strength, and function, significantly impacting overall health and quality of life in older adults. This narrative review explores emerging targets and potential treatments for sarcopenia, aiming to provide a comprehensive overview of current and prospective interventions.

METHODS

The review synthesizes current literature on sarcopenia treatment, focusing on recent advancements in muscle regeneration, mitochondrial function, nutritional strategies, and the muscle-microbiome axis. Additionally, pharmacological and lifestyle interventions targeting anabolic resistance and neuromuscular junction integrity are discussed.

RESULTS

Resistance training and adequate protein intake remain the cornerstone of sarcopenia management. Emerging strategies include targeting muscle regeneration through myosatellite cell activation, signaling pathways, and chronic inflammation control. Gene editing, stem cell therapy, and microRNA modulation show promise in enhancing muscle repair. Addressing mitochondrial dysfunction through interventions aimed at improving biogenesis, ATP production, and reducing oxidative stress is also highlighted. Nutritional strategies such as leucine supplementation and anti-inflammatory nutrients, along with dietary modifications and probiotics targeting the muscle-microbiome interplay, are discussed as potential treatment options. Hydration and muscle-water balance are emphasized as critical in maintaining muscle health in older adults.

CONCLUSIONS

A combination of resistance training, nutrition, and emerging therapeutic interventions holds potential to significantly improve muscle function and overall health in the aging population. This review provides a detailed exploration of both established and novel approaches for the prevention and management of sarcopenia, highlighting the need for further research to optimize these strategies.

Ultrasound Tissue Engineering Technology for Regulating Immune Microenvironment

The immune microenvironment is critical for the occurrence, progression, and treatment of diseases. Ultrasound tissue engineering technology utilizes ultrasound and the principles of tissue engineering to repair, regenerate, and functionally reconstruct biological tissues. Ultrasound therapy is a non‐invasive treatment modality that regulates the immune microenvironment and maintains homeostasis through various characteristic effects. Ultrasound‐responsive biomaterials utilize biological properties or drug/gene delivery to regulate the immune microenvironment under ultrasound stimulation for targeted and purposeful treatment. This article comprehensively and systematically reviews advancements in ultrasound tissue engineering technology for regulating the immune microenvironment. First, the changes in the immune microenvironment at different stages of the disease is briefly illustrated. It is then reviewed the regulation of the immune microenvironment by ultrasound and ultrasound‐responsive biomaterials in five types of diseases: tumor, cardiovascular system diseases, nervous system diseases, musculoskeletal diseases, and wound. Finally, the prospects of the ultrasound tissue engineering technology for regulating the immune microenvironment is summarized.

The Use of Extracellular Vesicles in Achilles Tendon Repair: A Systematic Review

Achilles tendon (AT) pathologies are common musculoskeletal conditions that can significantly impair function. Despite various traditional treatments, recovery is often slow and may not restore full functionality. The use of extracellular vesicles (EVs) has emerged as a promising therapeutic option due to their role in cell signaling and tissue regeneration. This systematic review aims to consolidate current in vivo animal study findings on the therapeutic effects of EVs on AT injuries. An extensive literature search was conducted using the PubMed, Scopus, and Embase databases for in vivo animal studies examining the effects of EVs on AT pathologies. The extracted variables included but were not limited to the study design, type of EVs used, administration methods, efficacy of treatment, and proposed therapeutic mechanisms. After screening, 18 studies comprising 800 subjects were included. All but one study reported that EVs augmented wound healing processes in the AT. The most proposed mechanisms through which this occurred were gene regulation of the extracellular matrix (ECM), the enhancement of macrophage polarization, and the delivery of therapeutic microRNAs to the injury site. Further research is warranted to not only explore the therapeutic potential of EVs in the context of AT pathologies, but also to establish protocols for their clinical application.

Genome-Wide Association Screens for Anterior Cruciate Ligament Tears

BACKGROUND

The etiopathogenesis of ACL rupture is not clarified. The aim of this study is to identify genomic regions and genetic variants relevant to anterior cruciate ligament injury susceptibility that could be involved in non-contact anterior cruciate ligament ruptures.

METHODS

A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with a PRISMA checklist and algorithm. A search of PubMed, MEDLINE, CINAHL, Cochrane, EMBASE, and Google Scholar databases was conducted using combinations of the terms "anterior cruciate ligament", "ACL", "rupture", "genetics", "single nucleotide polymorphisms", and "SNP" since the inception of the databases until 2021.

RESULTS

Twenty-three studies were included. A total of 7724 patients were analyzed. In total, 3477 patients had ACL ruptures and 4247 patients were controls. Genetic variants in genes encoding for collagens, elastin, fibrillin, matrix metalloproteinases, proteoglycans, angiogenesis-associated signaling cascade proteins, growth differentiation factors, tissue inhibitors of metalloproteases, interleukins, and fibrinogen were analyzed.

CONCLUSION

Findings regarding the association between genes encoding for collagen (COL3A1, COL1A1, and COL12A1), aggrecan (ACAN), decorin (DCN), matrix metalloproteinase (MMP3), interleukin 6 (IL-6), vascular endothelial growth factor A (VEGFA), biglycan (BGN), fibrinogen (FGB), and ACL injuries were found to be inconclusive. Additional evidence is required in order to establish substantial conclusions regarding the association between genetic variants and ACL rupture.

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.

LPS-Induced Modifications in Macrophage Transcript and Secretion Profiles Are Linked to Muscle Wasting and Glucose Intolerance

Macrophages are versatile immune cells that play crucial roles in tissue repair, immune defense, and the regulation of immune responses. In the context of skeletal muscle, they are vital for maintaining muscle homeostasis but macrophage-induced chronic inflammation can lead to muscle dysfunction, resulting in skeletal muscle atrophy characterized by reduced muscle mass and impaired insulin regulation and glucose uptake. Although the involvement of macrophage-secreted factors in inflammation-induced muscle atrophy is well-established, the precise intracellular signaling pathways and secretion factors affecting skeletal muscle homeostasis require further investigation. This study aimed to explore the regulation of macrophage-secreted factors and their impact on muscle atrophy and glucose metabolism. By employing RNA sequencing (RNA-seq) and proteome array, we uncovered that factors secreted by lipopolysaccharide (LPS)-stimulated macrophages upregulated markers of muscle atrophy and pro-inflammatory cytokines, while concurrently reducing glucose uptake in muscle cells. The RNA-seq analysis identified alterations in gene expression patterns associated with immune system pathways and nutrient metabolism. The utilization of gene ontology (GO) analysis and proteome array with macrophage-conditioned media revealed the involvement of macrophage-secreted cytokines and chemokines associated with muscle atrophy. These findings offer valuable insights into the regulatory mechanisms of macrophage-secreted factors and their contributions to muscle-related diseases.

Musculoskeletal Diseases: From Molecular Basis to Therapy

Musculoskeletal diseases (MSDs) comprise a plethora of different disorders (more than 150 conditions) affecting the locomotor system [...].

Biomimetic Fibers Based on Equidistant Micropillar Arrays Determines Chondrocyte Fate via Mechanoadaptability

It is recognized that the changes in the physical properties of extracellular matrix (ECM) result in fine-tuned cell responses including cell morphology, proliferation and differentiation. In this study, a novel patterned equidistant micropillar substrate based on polydimethylsiloxane (PDMS) is designed to mimic the collagen fiber-like network of the cartilage matrix. By changing the component of the curing agent to an oligomeric base, micropillar substrates with the same topology but different stiffnesses are obtained and it is found that chondrocytes seeded onto the soft micropillar substrate maintain their phenotype by gathering type II collagen and aggrecan more effectively than those seeded onto the stiff micropillar substrate. Moreover, chondrocytes sense and respond to micropillar substrates with different stiffnesses by altering the ECM-cytoskeleton-focal adhesion axis. Further, it is found that the soft substrate-preserved chondrocyte phenotype is dependent on the activation of Wnt/β-catenin signaling. Finally, it is indicated that the changes in osteoid-like region formation and cartilage phenotype loss in the stiffened sclerotic area of osteoarthritis cartilage to validate the changes triggered by micropillar substrates with different stiffnesses. This study provides the cell behavior changes that are more similar to those of real chondrocytes at tissue level during the transition from a normal state to a state of osteoarthritis.

Resveratrol, a Multitasking Molecule That Improves Skeletal Muscle Health

Resveratrol is a natural polyphenol utilized in Chinese traditional medicine and thought to be one of the determinants of the "French Paradox". More recently, some groups evidenced its properties as a calorie-restriction mimetic, suggesting that its action passes through the modulation of skeletal muscle metabolism. Accordingly, the number of studies reporting the beneficial effects of resveratrol on skeletal muscle form and function, in both experimental models and humans, is steadily increasing. Although studies on animal models confer to resveratrol a good potential to ameliorate skeletal muscle structure, function and performance, clinical trials still do not provide clear-cut information. Here, we first summarize the effects of resveratrol on the distinct components of the skeletal muscle, such as myofibers, the neuromuscular junction, tendons, connective sheaths and the capillary bed. Second, we review clinical trials focused on the analysis of skeletal muscle parameters. We suggest that the heterogeneity in the response to resveratrol in humans could depend on sample characteristics, treatment modalities and parameters analyzed; as well, this heterogeneity could possibly reside in the complexity of skeletal muscle physiology. A systematic programming of treatment protocols and analyses could be helpful to obtain consistent results in clinical trials involving resveratrol administration.

The Role of Genetics and Epigenetic Regulation in the Pathogenesis of Osteoarthritis

Osteoarthritis (OA) is progressive disease characterised by cartilage degradation, subchondral bone remodelling and inflammation of the synovium. The disease is associated with obesity, mechanical load and age. However, multiple pro-inflammatory immune mediators regulate the expression of metalloproteinases, which take part in cartilage degradation. Furthermore, genetic factors also contribute to OA susceptibility. Recent studies have highlighted that epigenetic mechanisms may regulate the expression of OA-associated genes. This review aims to present the mechanisms of OA pathogenesis and summarise current evidence regarding the role of genetics and epigenetics in this process.

Anti-Inflammatory Effects of Dietary Polyphenols through Inhibitory Activity against Metalloproteinases

Matrix metalloproteinases (MMPs) are zinc-dependent metalloproteinases that play important roles in a variety of diseases, including cancer, cardiovascular disease, diabetes, obesity, and brain diseases. Dietary polyphenols are thought to have a variety of beneficial effects on these diseases characterized by inflammation. Clinical studies have demonstrated that MMPs are in most cases upregulated in various inflammatory diseases, including osteoarthritis, rheumatoid arthritis, inflammatory bowel disease, and Alzheimer's disease. Studies using patient-derived human samples, animal studies, and cellular experiments have suggested that polyphenols may be beneficial against inflammatory diseases by suppressing MMP gene expression and enzyme activity. One important mechanism by which polyphenols exert their activity is the downregulation of reactive oxygen species that promote MMP expression. Another important mechanism is the direct binding of polyphenols to MMPs and their inhibition of enzyme activity. Molecular docking analyses have provided a structural basis for the interaction between polyphenols and MMPs and will help to explore new polyphenol-based drugs with anti-inflammatory properties.

Nutritional and Functional New Perspectives and Potential Health Benefits of Quinoa and Chia Seeds

Quinoa (Chenopodium quinoa Willd) and chia (Salvia hispanica) are essential traditional crops with excellent nutritional properties. Quinoa is known for its high and good quality protein content and nine essential amino acids vital for an individual's development and growth, whereas chia seeds contain high dietary fiber content, calories, lipids, minerals (calcium, magnesium, iron, phosphorus, and zinc), and vitamins (A and B complex). Chia seeds are also known for their presence of a high amount of omega-3 fatty acids. Both quinoa and chia seeds are gluten-free and provide medicinal properties due to bioactive compounds, which help combat various chronic diseases such as diabetes, obesity, cardiovascular diseases, and metabolic diseases such as cancer. Quinoa seeds possess phenolic compounds, particularly kaempferol, which can help prevent cancer. Many food products can be developed by fortifying quinoa and chia seeds in different concentrations to enhance their nutritional profile, such as extruded snacks, meat products, etc. Furthermore, it highlights the value-added products that can be developed by including quinoa and chia seeds, alone and in combination. This review focused on the recent development in quinoa and chia seeds nutritional, bioactive properties, and processing for potential human health and therapeutic applications.

The Beneficial Effects of Soybean Proteins and Peptides on Chronic Diseases

With lifestyle changes, chronic diseases have become a public health problem worldwide, causing a huge burden on the global economy. Risk factors associated with chronic diseases mainly include abdominal obesity, insulin resistance, hypertension, dyslipidemia, elevated triglycerides, cancer, and other characteristics. Plant-sourced proteins have received more and more attention in the treatment and prevention of chronic diseases in recent years. Soybean is a low-cost, high-quality protein resource that contains 40% protein. Soybean peptides have been widely studied in the regulation of chronic diseases. In this review, the structure, function, absorption, and metabolism of soybean peptides are introduced briefly. The regulatory effects of soybean peptides on a few main chronic diseases were also reviewed, including obesity, diabetes mellitus, cardiovascular diseases (CVD), and cancer. We also addressed the shortcomings of functional research on soybean proteins and peptides in chronic diseases and the possible directions in the future.

Effects of Epigallocatechin-3-Gallate on Matrix Metalloproteinases in Terms of Its Anticancer Activity

Epidemiological studies have shown that the consumption of green tea has beneficial effects against cancer. Basic studies have provided evidence that epigallocatechin gallate (EGCG) is a major contributor to these effects. Matrix metalloproteinases (MMPs) are zinc-dependent metalloproteinases with the ability to degrade the extracellular matrix proteins and are involved in various diseases including cancer in which MMPs have a critical role in invasion and metastasis. In this review, we discuss the effects of EGCG on several types of MMPs in the context of its anticancer activity. In the promoter region, MMPs have binding sites for at least one transcription factor of AP-1, Sp1, and NF-κB, and EGCG can downregulate these transcription factors through signaling pathways mediated by reactive oxygen species. EGCG can also decrease nuclear ERK, p38, heat shock protein-27 (Hsp27), and β-catenin levels, leading to suppression of MMPs' expression. Other mechanisms by which EGCG inhibits MMPs include direct binding to MMPs to prevent their activation and downregulation of NF-κB to suppress the production of inflammatory cytokines such as TNFα and IL-1β. Findings from studies on EGCG presented here may be useful in the development of more effective anti-MMP agents, which would give beneficial effects on cancer and other diseases.