Is there new hope for therapeutic matrix metalloproteinase inhibition?

Transcriptomic and functional characterization of megakaryocytic-derived platelet-like particles: impaired aggregation and prominent anti-tumor effects

Platelet-like particles (PLPs), derived from megakaryocytic cell lines MEG-01 and K-562, are widely used as a surrogate to study platelet formation and function. We demonstrate by RNA-Seq that PLPs are transcriptionally distinct from platelets. Expression of key genes in signaling pathways promoting platelet activation/aggregation, such as the PI3K/AKT, protein kinase A, phospholipase C, and α-adrenergic and GP6 receptor pathways, was missing or under-expressed in PLPs. Functionally, PLPs do not aggregate following epinephrine, collagen, or ADP stimulation. While PLPs aggregated in response to thrombin, they did not display enhanced expression of surface markers P-selectin and activated α2bβ3, in contrast to platelets. We have previously demonstrated that platelets physically couple to MDA-PCa-2b and RC77T/E prostate cancer (PCa) cells via specific ligand-receptor interactions, leading to platelet-stimulated cell invasiveness and apoptotic resistance, and reciprocal cell-induced platelet aggregation. In contrast, PLP interactions with PCa cells inhibited both cell invasion and apoptotic resistance while failing to promote PLP aggregation. Moreover, PLPs reduced platelet-PCa cell interactions and antagonized platelet-stimulated oncogenic effects in PCa cells. RNA-Seq analysis identified candidate ligand-transmembrane protein combinations involved in anti-tumorigenic signaling of PLPs to PCa cells. Antibody neutralization of the TIMP3-MMP15 and VEGFB-FGFR1 signaling axes reversed PLP-mediated anti-invasion and apoptotic sensitization, respectively. In summary, PLPs lack many transcriptomic, molecular and functional features of platelets and possess novel anti-tumorigenic properties. These findings indicate that PLPs may have a potential therapeutic role in targeting and disrupting the oncogenic signaling between platelets and cancer cells, offering a new avenue for anti-cancer strategies.

Directed evolution of metalloproteinase inhibitor TIMP-1 for selective inhibition of MMP-9 exploits catalytic and fibronectin domain interactions

Matrix metalloproteinase-9 (MMP-9) is a critical enzyme involved in extracellular matrix degradation and is strongly implicated in many diseases, including triple-negative breast cancer and other poor prognosis cancers. Selective inhibition of MMP-9 is therefore a promising therapeutic strategy. However, development of MMP inhibitors has been hindered by challenges in achieving specificity, with past efforts failing in clinical trials due to off-target effects and associated toxicity. Here, we present a novel approach to overcoming these challenges by engineering tissue inhibitor of metalloproteinases-1 (TIMP-1), a natural broad-spectrum MMP inhibitor, to achieve enhanced specificity and affinity for MMP-9. We demonstrate that TIMP-1 can be strategically engineered to selectively inhibit MMP-9 through modulating interactions not only with the catalytic domain but also with the unique fibronectin (FN) domains. By leveraging yeast surface display with strategic library design, we identified TIMP-1 variants that exploit multiple surface epitopes to optimize interactions with both the catalytic and FN domains of MMP-9. Molecular dynamics simulations further suggest how modifications in the N-terminal and C-terminal domains of TIMP-1 drive these selective interactions. The top engineered TIMP-1 variant exhibited significantly improved selectivity for MMP-9 in a manner dependent upon novel interactions with the FN domains, as validated through inhibition kinetics. This variant also demonstrated potent inhibition of MMP-9-driven triple-negative breast cancer cell invasiveness, underscoring the therapeutic potential of this approach. Our study highlights the versatility of TIMP-1 as a scaffold that can be optimized for highly selective MMP inhibition, providing new avenues for the development of targeted therapies.

Sepia Melanin for the Local Deactivation of Matrix Metalloproteinases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent enzymes that degrade the extracellular matrix and play essential functions in wound healing and tissue remodeling. However, the long-term overexpression of MMPs is associated with a chronic wound environment. Treatments that locally deactivate MMPs have been proposed to improve the outcomes of nonhealing chronic wounds. In this Letter, sepia melanin, a natural biopigment, is explored for the deactivation of MMPs, through chelation of zinc ions. Melanins have chemical functional groups to bind to various metal ions, which we demonstrate can be exploited for the deactivation of MMPs. Melanin's selectivity for zinc ions, and ability to deactivate MMPs that are associated with chronic wounds (MMP-1, MMP-2, and MMP-9) are examined, and its potential application in wound healing is demonstrated by functional in vitro tissue assays, mimicking the nonhealing wound environment. This is the first demonstration of the use of melanin for MMP deactivation.

Targeting oxidative stress-mediated regulated cell death as a vulnerability in cancer

Reactive oxygen species (ROS), regulators of cellular behaviors ranging from signaling to cell death, have complex production and control mechanisms to maintain a dynamic redox balance under physiological conditions. Redox imbalance is frequently observed in tumor cells, where ROS within tolerable limits promote oncogenic transformation, while excessive ROS induce a range of regulated cell death (RCD). As such, targeting ROS-mediated regulated cell death as a vulnerability in cancer. However, the precise regulatory networks governing ROS-mediated cancer cell death and their therapeutic applications remain inadequately characterized. In this Review, we first provide a comprehensive overview of the mechanisms underlying ROS production and control within cells, highlighting their dynamic balance. Next, we discuss the paradoxical nature of the redox system in tumor cells, where ROS can promote tumor growth or suppress it, depending on the context. We also systematically explored the role of ROS in tumor signaling pathways and revealed the complex ROS-mediated cross-linking networks in cancer cells. Following this, we focus on the intricate regulation of ROS in RCD and its current applications in cancer therapy. We further summarize the potential of ROS-induced RCD-based therapies, particularly those mediated by drugs targeting specific redox balance mechanisms. Finally, we address the measurement of ROS and oxidative damage in research, discussing existing challenges and future prospects of targeting ROS-mediated RCD in cancer therapy. We hope this review will offer promise for the clinical application of targeting oxidative stress-mediated regulated cell death in cancer therapy.

Invadopodia in cancer metastasis: dynamics, regulation, and targeted therapies

Pseudopodia and invadopodia are dynamic, actin-rich membrane structures extending from the cell surface. While pseudopodia are found in various cell types, invadopodia are exclusive to tumor cells and play a key role in cancer progression. These specialized structures enable tumor cells to degrade the extracellular matrix, breach tissue barriers, and invade surrounding tissues and blood vessels, thus facilitating metastasis. Extensive research has elucidated the distinct structure of invadopodia, the signaling pathways driving their formation, and their interaction with the tumor microenvironment. Integrin- and Src kinase-mediated signaling pathways regulate invadopodia dynamics. This review explores the mechanisms underlying invadopodia stabilization and highlights recent insights into their regulation by the tumor microenvironment. Particular emphasis is placed on the role of cell surface signaling in modulating invadopodia activity and the intracellular targeting of matrix metalloproteinases (MMPs) in enhancing invasive potential. A deeper understanding of invadopodia-driven cancer cell migration and metastasis provides valuable implications for therapeutic development. These findings support the potential for receptor-mediated and molecularly targeted therapies to inhibit tumor metastasis, improve clinical outcomes, and enhance the efficacy of existing cancer treatments.

Sequence and Structure at Play in Designing Allosteric Drugs and Alleviating the Drug Resistance

The advantages of allosteric drugs in targeting selected members of highly conserved protein families are well established. However, the discovery of allosteric effectors remains largely serendipitous, calling for a rational approach to account for their unique mechanisms and specificity towards protein targets. We show that the high-throughput quantification of allosteric signalling on a single-residue resolution allows one to delineate structural and sequence determinants of allosteric communication that are specific to individual members of a structurally conserved protein family. We demonstrate work of the approach using the matrix metalloproteinases (MMPs), a family of proteases also known to be "undruggable" because of their sequence/structural traits. Specifically, latent allosteric sites and effectors were identified and fine-tuned for precise functional modulation of MMP-7, MMP-12 and MMP-13. We also explored the allosteric effects of mutations in driving pathogenesis and emergence of the drug resistance, arguing that they should be considered in diagnostics and drug design frameworks. The multiplicity of allosteric sites and alternative effectors allow, for example, to rescue the therapeutic actions of orthosteric or allosteric drugs in cases of emerged resistance, because of mutations at the drug binding sites or other distal locations. To conclude, using the matrix metalloproteinases as an example of undruggable targets, we highlighted here advantages of the allosteric paradigm in drug design and illuminated a utility of our directed design protocol for the rational design of allosteric drugs.

Isoxazolyl steroid blocks the Shh signaling pathway and the expression of MMP-2 and MMP-9 in cervical carcinoma cell lines

Cervical cancer is the fourth leading cause of cancer death among women worldwide. Matrix metalloproteinases MMP-2 and MMP-9 play a leading role in the processes of invasion and metastasis in cervical cancer. Research on the development of MMP inhibitors not yielded the expected results due to their serious side effects. Study of signaling pathways involved in regulation of MMPs expression is of great importance for search of new classes of therapeutic drugs. Aberrant activation of the Sonic Hedgehog (Shh) signaling pathway is associated with increased MMPs in many types of human cancer. This study investigated the inhibitory action of 17β-((3-butylisoxazol-5-yl)methyl)-androst-5-en-3β-ol on the Shh signaling pathway key genes (Ptch, Smo, Gli) expression and MMP-2, MMP-9 genes expression in human cervical carcinoma cell lines (SiHa and CaSki) and keratinocytes (HaCaT). Cyclopamine was used for comparative analysis. Gene expression analysis was performed using real-time PCR; the effects on survival and cell cycle were studied using the MTT test and flow cytometry method. 17β-((3-butylisoxazol-5-yl)methyl)-androst-5-en-3β-ol had higher cytotoxicity and more effectively blocked the Shh signaling pathway genes and MMP-2 and MMP-9 genes compared to cyclopamine in all cell lines. The results obtained demonstrate potential of 17β-((3-butylisoxazol-5-yl)methyl)-androst-5-en-3β-ol as the anticancer drug that simultaneously block the Shh signaling pathway and MMP expression. We are confident that the search for substances capable of simultaneously affecting several key components involved in tumor progression is of great importance for the creation of next-generation therapeutic agents.

MMP3 at the crossroads: Linking molecular pathways to disease diagnosis and therapy

Matrix metalloproteinase 3 (MMP-3) is a multifaceted enzyme that plays a critical role in the regulation of extracellular matrix (ECM) dynamics, influencing both normal physiological and pathological processes. In addition to its established role in ECM degradation, MMP-3 is gaining recognition for modulating cellular behaviors such as inflammation, migration, and proliferation. Recent research has uncovered its capacity to activate latent signaling molecules, release growth factors from the ECM and interact with various cell surface receptors, linking MMP-3 to the progression of various diseases, including inflammatory diseases, infection diseases, cardiovascular diseases, neurodegenerative disorders, and cancer. The review provides an overview of MMP-3's molecular regulation, emphasizing the mechanisms controlling its expression and activity. We discuss MMP3's involvement in both ECM-dependent and independent pathways, and its potential as a diagnostic, prognostic biomarker in various diseases. Additionally, we explore therapeutic strategies targeting MMP-3, summarizing ongoing efforts to develop specific inhibitors and modulate its activity in different pathologic conditions. Through this review, we aim to consolidate the diverse functions of MMP-3 and provide new insights into future research directions, particularly in translating these findings into clinical applications.

Matrix Metalloproteinases in Glioma: Drivers of Invasion and Therapeutic Targets

Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteolytic enzymes that are crucial for the remodeling of the extracellular matrix, a process that is often co-opted by cancers, including brain tumors, to facilitate growth, invasion, and metastasis. In gliomas, MMPs contribute to a complex interplay involving tumor proliferation, angiogenesis, and immune modulation, thereby influencing tumor progression and patient prognosis. This review provides a comprehensive analysis of the roles of various MMPs in different types of gliomas, from highly malignant gliomas to metastatic lesions. Emphasis is placed on how the dysregulation of MMPs impacts tumor behavior, the association between specific MMPs and the tumor grade, and their potential as biomarkers for diagnosis and prognosis. Additionally, the current therapeutic approaches targeting MMP activity are discussed, exploring both their challenges and future potential. By synthesizing recent findings, this paper aims to clarify the broad significance of MMPs in gliomas and propose avenues for translational research that could enhance treatment strategies and clinical outcomes.

Extracellular matrix stiffness: mechanisms in tumor progression and therapeutic potential in cancer

Tumor microenvironment (TME) is a complex ecosystem composed of both cellular and non-cellular components that surround tumor tissue. The extracellular matrix (ECM) is a key component of the TME, performing multiple essential functions by providing mechanical support, shaping the TME, regulating metabolism and signaling, and modulating immune responses, all of which profoundly influence cell behavior. The quantity and cross-linking status of stromal components are primary determinants of tissue stiffness. During tumor development, ECM stiffness not only serves as a barrier to hinder drug delivery but also promotes cancer progression by inducing mechanical stimulation that activates cell membrane receptors and mechanical sensors. Thus, a comprehensive understanding of how ECM stiffness regulates tumor progression is crucial for identifying potential therapeutic targets for cancer. This review examines the effects of ECM stiffness on tumor progression, encompassing proliferation, migration, metastasis, drug resistance, angiogenesis, epithelial-mesenchymal transition (EMT), immune evasion, stemness, metabolic reprogramming, and genomic stability. Finally, we explore therapeutic strategies that target ECM stiffness and their implications for tumor progression.

High-throughput Activity Reprogramming of Proteases (HARP)

Developing potent and selective protease inhibitors remains a grueling, iterative, and often unsuccessful endeavor. Although macromolecular inhibitors can achieve single-enzyme specificity, platforms used for macromolecular inhibitor discovery are optimized for high-affinity binders, requiring extensive downstream biochemical characterization to isolate rare inhibitors. Here, we developed the High-throughput Activity Reprogramming of Proteases (HARP) platform, HARP is a yeast-based functional screen that isolates protease-inhibitory macromolecules from large libraries by coupling their inhibition of endoplasmic reticulum-resident proteases to a selectable phenotype on the cell surface. Endowed with high dynamic range and resolution, HARP enabled the isolation of low-nanomolar-range inhibitory nanobodies against tobacco etch virus protease and human kallikrein 6, including a rare 7.6 nM K I TEVp uncompetitive inhibitor. Structural modeling and deep sequencing all provide insights into the molecular determinants of inhibitors and reinforce HARP's foundational findings. Overall, HARP is a premier platform for discovering modulatory macromolecules from various synthetic scaffolds against enzyme targets.

Potential target within the tumor microenvironment - MT1-MMP

Matrix metalloproteinases are integral to the modification of the tumor microenvironment and facilitate tumor progression by degrading the extracellular matrix, releasing cytokines, and influencing the recruitment of immune cells. Among the matrix metalloproteinases, membrane-type matrix metalloproteinase 1 (MT1-MMP/MMP14) is the first identified membrane-type MMP and acts as an essential proteolytic enzyme that enables tumor infiltration and metastatic progression. Given the pivotal role of MT1-MMP in tumor progression and the correlation between its overexpression in tumors and unfavorable prognoses across multiple cancer types, a comprehensive understanding of the potential functional mechanisms of MT1-MMP is essential. This knowledge will aid in the advancement of diverse anti-tumor therapies aimed at targeting MT1-MMP. Although contemporary research has highlighted the considerable potential of MT1-MMP in targeted cancer therapy, studies pertaining to its application in cell therapy remain relatively limited. In this review, we delineate the structural characteristics and regulatory mechanisms of MT1-MMP expression, as well as its biological significance in tumorigenesis. Finally, we discussed the current status and prospects of anti-tumor therapies targeting MT1-MMP.

Biomaterials‐Involved Construction of Extracellular Matrices for Tumor Blockade Therapy

Extracellular matrices (ECMs) play a crucial role in the onset and progression of tumors by providing structural support and promoting the proliferation and metastases of tumor cells. Current therapeutic approaches targeting tumor ECMs focus on two main strategies: Inhibiting matrix degradation to prevent metastases and facilitating matrix degradation to enhance the penetration of drugs and immune cells. However, these strategies may lead to unintended consequences, such as tumor growth promotion, drug resistance, and side effects like fibrotic changes in healthy tissues. Biomaterials have made significant progress in fabricating artificial ECMs for tumor therapy by inducing biomineralization, fibrogenesis, or gelation. This perspective explores the fundamental concepts, benefits, and challenges of each technique. Additionally, future improvements and research directions in artificial ECMs are discussed, highlighting their potential to advance tumor therapy.

Involvement of the ubiquitin-proteasome system in the regulation of the tumor microenvironment and progression

The tumor microenvironment is a complex environment comprising tumor cells, non-tumor cells, and other critical non-cellular components. Some studies about tumor microenvironment have recently achieved remarkable progress in tumor treatment. As a substantial part of post-translational protein modification, ubiquitination is a crucial player in maintaining protein stability in cell signaling, cell growth, and a series of cellular life activities, which are also essential for regulating tumor cells or other non-tumor cells in the tumor microenvironment. This review focuses on the role and function of ubiquitination and deubiquitination modification in the tumor microenvironment while discussing the prospect of developing inhibitors targeting ubiquity-related enzymes, thereby providing ideas for future research in cancer therapy.

Endothelial TRIM35-Regulated MMP10 Release Exacerbates Calcification of Vascular Grafts

Vascular calcification is a highly regulated process in cardiovascular disease (CVD) and is strongly correlated with morbidity and mortality, especially in the adverse stage of vascular remodeling after coronary artery bypass graft surgery (CABG). However, the pathogenesis of vascular graft calcification, particularly the role of endothelial-smooth muscle cell interaction, is still unclear. To test how ECs interact with SMCs in artery grafts, single-cell analysis of wild-type mice is first performed using an arterial isograft mouse model and found robust cytokine-mediated signaling pathway activation and SMC proliferation, together with upregulated endothelial tripartite motif 35 (TRIM35) expression. Unexpectedly, severe SMC calcification in artery grafts is found in TRIM35 conditional endothelial knockout (cKO) mice. Calcified medium (comprising calcium chloride and beta-glycerophosphate)-induced calcium deposition in vitro is also found in SMCs cocultured with TRIM35 knockout endothelium. This extraordinary phenomenon is further confirmed to be induced by increased MMP10 secretion. Mechanistically, endothelial TRIM35 inhibits MMP10 expression and secretion by promoting K63-linked ubiquitination of RelB and maintaining its nuclear localization, consequently inhibiting nuclear transcription of MMP10 through the noncanonical NF-κB signaling pathway. Targeting MMP10 in situ in arterial isografts can effectively alleviate vascular calcification caused by conditional endothelial TRIM35 knockout. These findings demonstrated that TRIM35 inhibited vascular calcification during arterial isograft remodeling, a process that is driven by the aberrant secretion of endothelial MMP10. Targeting MMP10 pathway may be a potential therapeutic strategy for vascular calcification in vessel grafts.

Effect of TIMPs and their minimally engineered variants in blocking invasion and migration of brain cancer cells

Matrix metalloproteinases (MMPs) are crucial in remodeling the extracellular matrix (ECM), modulating key processes involved in cancer progression, such as migration, invasion, angiogenesis, and metastasis. The overexpression of MMPs, particularly MMP-9, is markedly observed in glioblastoma multiforme (GBM), an aggressive primary brain tumor known for its diffuse and infiltrative nature. Tissue inhibitors of metalloproteinases (TIMPs), endogenous MMP inhibitors, offer significant therapeutic potential due to their wider interaction interfaces relative to small molecule inhibitors. Here, we studied the effect of wild-type human TIMP-1 and TIMP-3 and minimal TIMP variants (mTC1 and mTC3), previously engineered for MMP inhibition, on migration and invasion of GBM cells. Our study focused on minimal TIMP variants, due to their small molecular size and potential in higher cellular uptake and delivery, to assess their potential in cell-based assays. The results demonstrated that the minimal TIMP variants, mTC1, and mTC3, effectively inhibit MMP activity underscoring their potential to limit tumor invasion and progression. Given the lethal nature of GBM and the limited efficacy of current therapies, the application of TIMPs and their engineered minimal variants represents a novel and potentially transformative approach to regulating MMP activity in GBM.

Exploring correlations between gut mycobiome and lymphocytes in melanoma patients undergoing anti-PD-1 therapy

Research has shown that the microbiome can influence how the immune system responds to melanoma cells, affecting the course of the disease and the outcome of the therapy. Here, we used the metagenomic approach and flow cytometry analyses of blood cells to discover correlations between gut fungi of metastatic melanoma patients enrolled in anti-PD-1 therapy and lymphocytes in their blood.We analyzed the patterns of associations before the first administration of anti-PD-1 therapy (BT, n = 61) and in the third month of the therapy (T3, n = 37), allowing us to track changes during treatment. To understand the possible impact of gut fungi on the efficacy of anti-PD-1 therapy, we analyzed the associations in clinical beneficiaries (CB, n = 37) and non-beneficiaries (NB, n = 24), as well as responders (R, n = 28) and non-responders (NR, n = 33).Patients with LDH < 338 units/L, overall survival (OS) > 12, CB, as well as R, had lower levels of Shannon diversity (p = 0.02, p = 0.05, p = 0.05, and p = 0.03, respectively). We found that the correlation pattern between intestinal fungi and lymphocytes was specific to the type of response, positive or negative. When comparing CB and NB groups, correlations with opposite directions were detected for C. albicans, suggesting a response-specific immune reaction. For CB, M. restricta exhibited a set of correlations with different types of lymphocytes, with prevalent positive correlations, suggesting a robust immune response in the CB group. This result extends our former research, where M. restricta and C. albicans were associated with an increased risk of melanoma progression and a poorer response to anti-PD-1 treatment.

Targeted approach to determine the impact of cancer-associated protease variants

Several steps of cancer progression, from tumor onset to metastasis, critically involve proteolytic activity. To elucidate the role of proteases in cancer, it is particularly important to consider single-nucleotide variants (SNVs) that affect the active site of proteases, thereby influencing cleavage specificity, substrate processing, and thus cancer cell behavior. To facilitate systematic studies, we here present a targeted approach to determine the impact of cancer-associated protease variants (TACAP). Starting with the semiautomated identification of potential specificity-modulating SNVs, our workflow comprises mass spectrometry-based cleavage specificity profiling and substrate identification, localization, and inhibitor studies, followed by functional analyses investigating cancer cell properties. To demonstrate the feasibility of TACAP, we analyzed the meprin β R238Q variant. This amino acid exchange R238Q leads to a loss of meprin β's characteristic cleavage preference for acidic amino acids at P1' position, accompanied with changes in substrate pool and inhibitor affinity compared to meprin β wild type.

RECK as a Potential Crucial Molecule for the Targeted Treatment of Sepsis

Reversion inducing cysteine rich protein with kazal motifs (RECK), a Kazal motif-containing protein, regulates pro-inflammatory cytokines production, migration of inflammatory cells, vascular endothelial growth factor (VEGF) and Wnt pathways and plays critical roles in septic inflammatory storms and vascular endothelial dysfunction. Recently, RECK has been defined as the negative regulator of adisintegrin and metalloproteinases (ADAMs) and matrix metalloproteinases (MMPs), which are both membrane "molecular scissors" and aggravate the poor prognosis of sepsis. To better understand the roles of RECK and the related mechanisms, we make here a systematic and in-depth review of RECK. We first summarize the findings on structural characteristics of RECK protein and the regulation at the transcription, post-transcription, or protein level of RECK. Then, we discuss the roles of RECK in inflammation, infection, and vascular injury by focusing on the RECK function on ADAMs and MMPs, as well as the pathways of VEGF, WNT, angiopoietin, and notch signaling. In conclusion, RECK participation as a guardian in the development of sepsis provides insight into the strategies of precisely intervening in RECK dysregulationfor the treatment of sepsis.

An overview of matrix metalloproteinase-12 in multiple disease conditions, potential selective inhibitors, and drug designing strategies

Matrix metalloproteases (MMPs) are the proteolytic enzymes accountable for extracellular matrix (ECM) modification through their Zn2+-dependent catalytic activity. Among these, MMP-12 is one of the crucial MMPs that contributes to various disease states including different types of cancers and other major pathophysiological conditions including COPD, asthma, emphysema, skin diseases, arthritis, vascular diseases, and neurological disorders. The majority of the MMP-12 inhibitors should have three constitutional pharmacophoric features (i.e., a hydrophobic group to occupy the S1' pocket, a zinc-binding motif for chelating to the catalytic Zn2+ ion present at the catalytic site, and a flexible and hydrogen bond forming linker region between the S1' pocket substituent and the zinc chelating group for interacting with the catalytic and Ω-loop amino acid residues). This review mainly focuses on the various roles of MMP-12 in different diseases along with the structural comparison with other MMPs as well as promising and MMP-12-selective inhibitors and molecular modeling studies performed on MMP-12 inhibitors. Therefore, this review will provide comprehensive information to the researchers for designing effective and MMP-12-selective inhibitors for therapeutic advancement in the future.

Matrix Metallopeptidase 9 Promotes Contraction in Human Uterine Myometrium

Matrix metallopeptidase 9 (MMP9) is a secreted zinc-dependent peptidase known for extracellular remodeling. MMP9 is elevated in tissues from women experiencing preterm labor, and previous research has shown that the addition of combined matrix metallopeptidases 2 and 9 (MMP2/9) enhances uterine contractions. We hypothesized that adding MMP9 alone would enhance myometrial contractions and that specific MMP9 inhibition would suppress uterine contractions. In myometrial tissue from women undergoing term Caesarean sections, we observed an increased contractile response as measured by area under the curve over time in tissues treated with MMP9 compared to vehicle-treated controls (p = 0.0003). This effect was primarily due to increased contraction frequency in MMP9-treated tissues compared to controls (p < 0.0001). Specific inhibition of MMP9 with the highly selective MMP9 inhibitor 1 (AG-L-66085) reduced contractile responses in myometrial tissues from pregnant women. We observed a reduction in the oxytocin-induced contractile response as measured by area under the curve over time (p < 0.0001) and contraction amplitude (p < 0.0068) in AG-L-66085-treated tissues compared to vehicle-treated controls. To determine the effects of MMP9 inhibition in the absence of exogenous oxytocin, we tested the effects of AG-L-66085 on spontaneous contractions. The area under the curve (p = 0.0415) and amplitude (p = 0.0354) of spontaneous contractions were reduced in response to 1 μM AG-L-66085, and the inhibitory effects increased as the AG-L-66085 concentration increased. Together, these data support the hypothesis that elevated MMP9 promotes myometrial contractions and labor, while its inhibition promotes relaxation.

The Diverse Pathways for Cell Surface MT1-MMP Localization in Migratory Cells

Controlled cell migration is an essential biological process in health, while uncontrolled cell migration contributes to disease progression. For cells to migrate through tissue, they must first degrade the extracellular matrix (ECM), which acts as a physical barrier to cell migration. A type I transmembrane-type matrix metalloproteinase, MT1-MMP, is the key enzyme involved in this process. It has been extensively shown that MT1-MMP promotes the migration of different cell types in tissue, including fibroblasts, epithelial cells, endothelial cells, macrophages, mesenchymal stem cells, and cancer cells. MT1-MMP is tightly regulated at different levels, and its localization to leading-edge membrane structures is an essential process for MT1-MMP to promote cellular invasion. Different cells display different motility-associated membrane structures, which contribute to their invasive ability, and there are diverse mechanisms of MT1-MMP localization to these structures. In this article, we will discuss the current understanding of MT1-MMP regulation, in particular, localization mechanisms to these different motility-associated membrane structures.

Exploring the therapeutic potential of fibroadipogenic progenitors in muscle disease

Skeletal muscle relies on its inherent self-repair ability to withstand continuous mechanical damage. Myofiber-intrinsic processes facilitate the repair of damage to sarcolemma and sarcomeres, but it is the coordinated interaction between muscle-resident satellite and stromal cells that are crucial in the regeneration of muscles to replace the lost muscle fibers. Fibroadipogenic progenitors (FAPs), are muscle-resident mesenchymal cells that are notable for their role in creating the dynamic stromal niche required to support long-term muscle homeostasis and regeneration. While FAP-mediated extracellular matrix formation and the establishment of a homeostatic muscle niche are essential for maintaining muscle health, excessive accumulation of FAPs and their aberrant differentiation leads to the fibrofatty degeneration that is a hallmark of myopathies and muscular dystrophies. Recent advancements, including single-cell RNA sequencing and in vivo analysis of FAPs, are providing deeper insights into the functions and specialization of FAPs, shedding light on their roles in both health and disease. This review will explore the above insights, discussing how FAP dysregulation contributes to muscle diseases. It will offer a concise overview of potential therapeutic interventions targeting FAPs to restore disrupted interactions among FAPs and muscle-resident cells, ultimately addressing degenerative muscle loss in neuromuscular diseases.

ScRNA-Seq Analysis of Tongue Tissues in Chronic Hyperplastic Candidiasis

Chronic hyperplastic candidiasis (CHC) is a rare but severe subtype of oral candidiasis distinguished by its potential malignant transformation and suboptimal response to antifungal therapies. However, the cells and mechanisms that play key roles in this process remain unclear. Therefore, we performed the first single-cell RNA sequencing (scRNA-seq) analysis of CHC-affected tongue tissues to reveal the microenvironmental changes and immunological etiology of CHC. First, the features of CHC lesions manifesting as thickening and hardening nodular lesions, including their pathological and microbiological characteristics, were elucidated. Then, a comprehensive cellular atlas and distinct immune landscape in CHC compared with healthy tissues were characterized using scRNA-seq, highlighting significant modifications in the cell number and functionality of fibroblasts and T/NK cells. Importantly, the central role of fibroblasts in cell-cell interactions in CHC was hinted, and possible ligand-receptor pairs mainly associated with inflammation and carcinogenesis were identified. Moreover, it was revealed that significant functional activation of fibroblasts, related to the activation of the epithelial-mesenchymal transition pathways and increased expression of collagen I, matrix metalloproteinase 1 (MMP1), and MMP2, could be a hallmark of CHC, correlating with CHC's clinical characteristics of tongue hardening and intense inflammation. Notably, there is sequencing evidence of the recruitment of CD8+Tex cells and activation of PD-1 and TIGIT immune checkpoint pathways. Moreover, cDC_LAMP3 cells exhibited high CD274 expression, suggesting immune exhaustion and an increased susceptibility to carcinogenesis. This pioneering study provides valuable insights into CHC pathogenesis and immune responses, enhancing our understanding of potential therapeutic strategies.

Inhibition of matrix metalloproteinases to reduce blood brain barrier disruption and haemorrhagic transformation in ischaemic stroke: Go broad or go narrow?

Ischaemic stroke characterises impulsive cerebral-region hypoxia due to deep intracerebral arteriole blockage, often accompanied by permanent cerebral infarction and cognitive impairment. Thrombolysis with recombinant tissue plasminogen activator (rtPA) and thrombectomy remain the only guidance-approved therapies. However, emerging data draws clear links between such therapies and haemorrhage transformation, which occur when cerebral vasculature is damaged during ischaemia/reperfusion. Studies have shown that matrix metalloproteinases (MMPs) play a significant role in haemorrhage transformation, by depleting the extracellular matrix (ECM) and disrupting the blood brain barrier (BBB). Inhibitors of MMPs may be used to prevent ischaemic stroke patients from BBB disruption and haemorrhage transformation, particularly for those receiving rtPA treatment. Preclinical studies found that inhibition of MMPs with agents or in knock out mice, effectively reduced BBB disruption and infarct volume, leading to improved ischaemic stroke outcomes. At present, MMP inhibition is not an approved therapy for stroke patients. There remain concerns about timing, dosing, duration of MMP inhibition and selection of either broad spectrum or specific MMP inhibitors for stroke patients. This review aims to summarize current knowledge on MMP inhibition in ischaemic stroke and explore whether a broad spectrum or a specific MMP inhibitor should be used for ischaemic stroke patient treatment. It is crucial to inhibit MMP activities early and sufficiently to ensure BBB intact during ischaemia and reperfusion, but also to reduce side effects of MMP inhibitors to minimum. Recent advance in stroke therapy by thrombectomy could aid in such treatment with intra-arterially delivery of MMP inhibitors (and/or antioxidants).

Targeting Invasion: The Role of MMP-2 and MMP-9 Inhibition in Colorectal Cancer Therapy

Colorectal cancer (CRC) remains one of the most prevalent and lethal cancers worldwide, prompting ongoing research into innovative therapeutic strategies. This review aims to systematically evaluate the role of gelatinases, specifically MMP-2 and MMP-9, as therapeutic targets in CRC, providing a critical analysis of their potential to improve patient outcomes. Gelatinases, specifically MMP-2 and MMP-9, play critical roles in the processes of tumor growth, invasion, and metastasis. Their expression and activity are significantly elevated in CRC, correlating with poor prognosis and lower survival rates. This review provides a comprehensive overview of the pathophysiological roles of gelatinases in CRC, highlighting their contribution to tumor microenvironment modulation, angiogenesis, and the metastatic cascade. We also critically evaluate recent advancements in the development of gelatinase inhibitors, including small molecule inhibitors, natural compounds, and novel therapeutic approaches like gene silencing techniques. Challenges such as nonspecificity, adverse side effects, and resistance mechanisms are discussed. We explore the potential of gelatinase inhibition in combination therapies, particularly with conventional chemotherapy and emerging targeted treatments, to enhance therapeutic efficacy and overcome resistance. The novelty of this review lies in its integration of recent findings on diverse inhibition strategies with insights into their clinical relevance, offering a roadmap for future research. By addressing the limitations of current approaches and proposing novel strategies, this review underscores the potential of gelatinase inhibitors in CRC prevention and therapy, inspiring further exploration in this promising area of oncological treatment.

A novel biomarker of COVI-19: MMP8 emerged by integrated bulk RNAseq and single-cell sequencing

COVID-19 has been emerging as the most influential illness which has caused great costs to the heath of population and social economy. Sivelestat sodium (SS) is indicated as an effective cure for lung dysfunction, a characteristic symptom of COVID-19 infection, but its pharmacological target is still unclear. Therefore, a deep understanding of the pathological progression and molecular alteration is an urgent issue for settling the diagnosis and therapy problems of COVID-19. In this study, the bulk ribonucleic acid sequencing (RNA-seq) data of healthy donors and non-severe and severe COVID-19 patients were collected. Then, target differentially expressed genes (DEGs) were screened through integrating sequencing data and the pharmacological database. Besides, with the help of functional and molecular interaction analyses, the potential effect of target gene alteration on COVID-19 progression was investigated. Single-cell sequencing was performed to evaluate the cell distribution of target genes, and the possible interaction of gene-positive cells with other cells was explored by intercellular ligand-receptor pattern analysis. The results showed that matrix metalloproteinase 8 (MMP8) was upregulated in severe COVID-19 patients, which was also identified as a targeting site to SS. Additionally, MMP8 took a core part in the regulatory interaction network of the screened DEGs in COVID-19 and was dramatically correlated with the inflammatory signaling pathway. The further investigations indicated that MMP8 was mainly expressed in myelocytes with a high degree of heterogeneity. MMP8-positive myelocytes interacted with other cell types through RETN-TLR4 and RETN-CAP1 ligand-receptor patterns. These findings emphasize the important role of MMP8 in COVID-19 progression and provide a potential therapeutic target for COVID-19 patients.

Targeting Matrix Metalloproteinases and Their Inhibitors in Melanoma

Malignant melanoma is one of the most important dermatological neoplasms. The high mortality rate associated with this skin disease is primarily due to the occurrence of metastases, while the diagnosis and treatment of melanoma in its early stages has a favorable prognosis. Early detection is crucial because the success of treatment is directly related to the depth of cancerous growth. The family of matrix metalloproteinases (MMPs) plays a critical role in the initiation and progression of melanoma. Prominent MMPs, including MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, and MMP-14, have been shown to significantly contribute to the development of melanoma. The tumor microenvironment, particularly the extracellular matrix (ECM), has emerged as a critical factor in modulating cancer progression. This review focuses on the role of matrix metalloproteinases and their inhibitors in ECM degradation and the subsequent progression of melanoma, as well as their potential as therapeutic targets.

Targeting extracellular matrix stiffness for cancer therapy

The physical characteristics of the tumor microenvironment (TME) include solid stress, interstitial fluid pressure, tissue stiffness and microarchitecture. Among them, abnormal changes in tissue stiffness hinder drug delivery, inhibit infiltration of immune killer cells to the tumor site, and contribute to tumor resistance to immunotherapy. Therefore, targeting tissue stiffness to increase the infiltration of drugs and immune cells can offer a powerful support and opportunities to improve the immunotherapy efficacy in solid tumors. In this review, we discuss the mechanical properties of tumors, the impact of a stiff TME on tumor cells and immune cells, and the strategies to modulate tumor mechanics.

Proteolysis and Contractility Regulate Tissue Opening and Wound Healing by Lung Fibroblasts in 3D Microenvironments

Damage and repair are recurring processes in tissues, with fibroblasts playing key roles by remodeling extracellular matrices (ECM) through protein synthesis, proteolysis, and cell contractility. Dysregulation of fibroblasts can lead to fibrosis and tissue damage, as seen in idiopathic pulmonary fibrosis (IPF). In advanced IPF, tissue damage manifests as honeycombing, or voids in the lungs. This study explores how transforming growth factor-beta (TGF-β), a crucial factor in IPF, induces lung fibroblast spheroids to create voids in reconstituted collagen through proteolysis and cell contractility, a process we termed as hole formation. These voids reduce when proteases are blocked. Spheroids mimic fibroblast foci observed in IPF. Results indicate that cell contractility mediates tissue opening by stretching fractures in the collagen meshwork. Matrix metalloproteinases (MMPs), including MMP1 and MT1-MMP, are essential for hole formation, with invadopodia playing a significant role. Blocking MMPs reduces hole size and promotes wound healing. This study shows how TGF-β induces excessive tissue destruction and how blocking proteolysis can reverse damage, offering insights into IPF pathology and potential therapeutic interventions.

Inhibition of osteosarcoma metastasis in vivo by targeted downregulation of MMP1 and MMP9

Osteosarcoma (OS) mortality stems from lung metastases. Matrix metalloproteinases (MMPs) facilitate metastatic dissemination by degrading extracellular matrix components. Herein we studied the impact of targeted MMP downregulation on OS metastasis. Differential gene expression analysis of human OS cell lines revealed high MMP9 expression in the majority of OS cell lines. Furthermore, 143B, a metastatic OS cell line, exhibited increased MMP1 and MMP9 mRNA levels. Gene set enrichment analysis on metastatic and non-metastatic OS patient specimens indicated epithelial-mesenchymal transition as the most enriched gene set, with MMP9 displaying strong association to genes in this network. Using the same dataset, Kaplan-Meier analysis revealed a correlation between MMP1 expression and dismal patient survival. Hence, we undertook targeted suppression of MMP1 and MMP9 gene expression in OS cell lines. The ability of OS cells to migrate and form colonies was markedly reduced upon MMP1 and MMP9 downregulation, whereas their cell proliferation capacity remained intact. MMP9 downregulation decreased tumor growth and lung metastases area in an orthotopic mouse OS model. Consistently, human OS lung metastasis specimens displayed marked MMP9 protein expression. Our findings highlight the role of MMP1 and MMP9 in OS metastasis, warranting further exploration of simultaneous inhibition of MMPs for future OS therapeutics.

Hereditary Amyloidosis: Insights Into a Fibrinogen A Variant Protein

Amyloidosis are a group of diseases in which soluble proteins aggregate and deposit in fibrillar conformation extracellularly in tissues. The effectiveness of therapeutic strategies depends on the specific protein involved, being crucial to accurately determine its nature. Moreover, following the diagnosis, the search for the mutation within relatives allows the clinical advice. Here we report the precise diagnosis and explored the possible reasons of the structural pathogenicity for a renal amyloidosis related to a fibrinogen Aα-chain variant. Whole-exome sequencing and GATK calling pipeline were leveraged to characterize the protein variant present in a patient with kidney failure. Bioinformatics strategies were applied to suggest potential explanations of the variants aggregation. Our pipeline allowed the identification of a single-point variant of fibrinogen Aα-chain, which opened the possibility of curative transplantation. In silico structural analysis suggested that the pathogenicity of the variant may be attributed to a heightened susceptibility to yield a peptide prone to deposit as an oligomer with a β-sheet structure. Exploiting the comprehensive coverage of whole-genome sequencing, we managed to fill a vacant stage in the diagnosis of hereditary amyloidosis and to stimulate the advancement in biomedicine.

Exploring molecular mechanisms of postoperative delirium through multi-omics strategies in plasma exosomes

Currently, the diagnosis of delirium is solely based on clinical observation, lacking objective diagnostic tools, and the regulatory networks and pathological mechanisms behind it are not yet fully understood. Exosomes have garnered considerable interest as potential biomarkers for a variety of illnesses. This research aimed to delineate both the proteomic and metabolomic landscapes inherent to exosomes, assessing their diagnostic utility in postoperative delirium (POD) and understanding the underlying pathophysiological frameworks. Integrated analyses of proteomics and metabolomics were conducted on exosomes derived from plasma of individuals from both the non-postoperative delirium (NPOD) control group and the POD group. Subsequently, the study utilized the Connectivity Map (CMap) methodology for the identification of promising small-molecule drugs and carried out molecular docking assessments to explore the binding affinities with the enzyme MMP9 of these identified molecules. We identified significant differences in exosomal metabolites and proteins between the POD and control groups, highlighting pathways related to neuroinflammation and blood-brain barrier (BBB) integrity. Our CMap analysis identified potential small-molecule therapeutics, and molecular docking studies revealed two compounds with high affinity to MMP9, suggesting a new therapeutic avenue for POD. This study highlights MMP9, TLR2, ICAM1, S100B, and glutamate as key biomarkers in the pathophysiology of POD, emphasizing the roles of neuroinflammation and BBB integrity. Notably, molecular docking suggests mirin and orantinib as potential inhibitors targeting MMP9, providing new therapeutic avenues. The findings broaden our understanding of POD mechanisms and suggest targeted strategies for its management, reinforcing the importance of multidimensional biomarker analysis and molecular targeting in POD intervention.

The Temporomandibular Joint and the Human Body: A New Perspective on Cross Talk

Background: As a unique joint that facilitates the articulation of the upper and lower jaws, the temporomandibular joint (TMJ) is concerned with several critical functions, such as speech and mastication. Pain that can become incapacitating is a result of temporomandibular disorders (TMDs), which are complex disorders affecting the masticatory muscles and the TMJ. Several anomalies and TMDs have an interdisciplinary relationship. Complementary and concurrent disorders may be caused by occlusal anomalies, psychological disorders, and changes in spine posture. Methods: This article examines the clinical characteristics of TMDs, their classification, their etiological factors, and the impact of TMJ disorders on the human body with reference to their anatomies and histological structures. Results: The clinical picture of some TMJ pathologies may be unknown, so certain biomarkers, such as cytokines, may be useful for an accurate diagnosis as they are frequently seen in TMJ disorders. Furthermore, novel therapeutic approaches that target pro-inflammatory cytokines and treat TMDs by using tissue engineering and regenerative medicine while permitting TMJ cartilage and bone regeneration may offer numerous benefits that require clinical translation. Conclusions: Implementation of recent modalities such as microvesicles and platelet-rich plasma in growth factors may provide a promising approach to enhance bone formation. In addition, we target different biological markers that give insights into the introduction of new pharmaceutical agents for therapy.

Engineered TIMP2 with narrow MMP-9 specificity is an effective inhibitor of invasion and proliferation of triple-negative breast cancer cells

Matrix metalloproteinases (MMPs) are a family of endopeptidases that degrade extracellular matrix proteins, functioning in various physiological processes such as tissue remodeling, embryogenesis, and morphogenesis. Dysregulation of these enzymes is linked to multiple diseases. Specific inhibition of particular MMPs is crucial for anti-MMP drug development as some MMPs have shown antidisease properties. In this study, we aimed to design a highly specific inhibitor of MMP-9, that plays a crucial role in cell invasion and metastasis, using tissue inhibitor of metalloproteinases 2 (TIMP2s), an endogenous broad-family MMP inhibitor, as a prototype. In our earlier work, we were able to narrow down the specificity of the N-terminal domain of TIMP2 (N-TIMP2) toward MMP-9, yet at the expense of lowering its affinity to MMP-9. In this study, a library of N-TIMP2 mutants based on previous design with randomized additional positions was sorted for binding to MMP-9 using yeast surface display. Two selected N-TIMP2 mutants were expressed, purified, and their inhibitory activity against a panel of MMPs was measured. The best engineered N-TIMP2 mutant (REY) exhibited a 2-fold higher affinity to MMP-9 than that of the WT N-TIMP2, and 6- to 1.1 x 104-fold increase in binding specificity toward MMP-9 compared to five alternative MMPs. Moreover, REY demonstrated a significant increase in inhibition of cell invasion and proliferation compared to the WT N-TIMP2 in MDA-MB-231 breast cancer cells. Therefore, our engineered N-TIMP2 mutant emerges as a promising candidate for future therapeutic development, offering precise targeting of MMP-9 in MMP-9-driven diseases.

Research progress of BRD4 in head and neck squamous cell carcinoma: Therapeutic application of novel strategies and mechanisms

Bromodomain-containing protein 4 (BRD4) belongs to the bromodomain and extra-terminal domain (BET) protein family, which plays a crucial role in recognizing acetylated lysine residues in chromatin. The abnormal expression of BRD4 contributes to the development of various human malignant tumors, including head and neck squamous cell carcinoma (HNSCC). Recent studies have shown that BRD4 inhibition can effectively prevent the proliferation and growth of HNSCC. However, the specific role and mechanism of BRD4 in HNSCC are not yet fully clarified. This article will briefly summarize the critical role of BRD4 in the pathogenesis of HNSCC and discuss the potential clinical applications of targeting BRD4 in HNSCC therapy. We further inquiry the challenges and opportunities for HNSCC therapies based on BRD4 inhibition, including BRD4 inhibitor combination with conventional chemotherapy, radiotherapy, and immunotherapy, as well as new strategies of BRD4-targeting drugs and BRD4 proteolysis-targeting chimeras (PROTACs). Moreover, we will also offer outlook on the associated challenges and future directions of targeting BRD4 for the treatment of patients with HNSCC.

Water-medicated specifically targeting the S1 pockets among serine proteases using an arginine analogue

Because of the high similarity in structure and sequence, it is challenging to distinguish the S1 pocket among serine proteases, primarily due to the only variability at residue 190 (A190 and S190). Peptide or protein-based inhibitors typically target the negatively charged S1 pocket using lysine or arginine as the P1 residue, yet neither discriminates between the two S1 pocket variants. This study introduces two arginine analogues, L-4-guanidinophenylalanine (12) and L-3-(N-amidino-4-piperidyl)alanine (16), as novel P1 residues in peptide inhibitors. 16 notably enhances affinities across all tested proteases, whereas 12 specifically improved affinities towards proteases possessing S190 in the S1 pocket. By crystallography and molecular dynamics simulations, we discovered a novel mechanism involving a water exchange channel at the bottom of the S1 pocket, modulated by the variation of residue 190. Additionally, the specificity of 12 towards the S190-presenting S1 pocket is dependent on this water channel. This study not only introduces novel P1 residues to engineer inhibitory potency and specificity of peptide inhibitors targeting serine proteases, but also unveils a water-mediated molecular mechanism of targeting serine proteases.

Human Amniotic Epithelial Stem Cells Promote Colonic Recovery in Experimental Colitis via Exosomal MiR-23a-TNFR1-NF-κB Signaling

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, manifests as chronic intestinal inflammation with debilitating symptoms, posing a significant burden on global healthcare. Moreover, current therapies primarily targeting inflammation can lead to immunosuppression-related complications. Human amniotic epithelial stem cells (hAESCs), which exhibit low immunogenicity and ethical acceptability, have gained attention as potential therapeutics. In this study, it is demonstrated that their encapsulation in a hydrogel and administration via anal injection enhanced the colonic mucosal barrier repair in a murine colitis model induced by dextran sodium sulfate during the recovery phase. The underlying mechanism involved the release of exosomes from hAESCs enriched with microRNA-23a-3p, which post-transcriptionally reduced tumor necrosis factor receptor 1 expression, suppressing the nuclear factor-κB pathway in colonic epithelial cells, thus played a key role in inflammation. The novel approach shows potential for IBD treatment by restoring intestinal epithelial homeostasis without the immunosuppressive therapy-associated risks. Furthermore, the approach provides an alternative strategy to target the key molecular pathways involved in inflammation and promotes intestinal barrier function using hAESCs and their secreted exosomes. Overall, this study provides key insights to effectively treat IBD, addresses the unmet needs of patients, and reduces related healthcare burden.

Matrix metalloproteinase landscape in the imiquimod-induced skin inflammation mouse model

Inflammation and autoimmunity are known as central processes in many skin diseases, including psoriasis. It is therefore important to develop pre-clinical models that describe disease-related aspects to enable testing of pharmaceutical drug candidates and formulations. A widely accepted pre-clinical model of psoriasis is the imiquimod (IMQ)-induced skin inflammation mouse model, where topically applied IMQ provokes local skin inflammation. In this study, we investigated the abundance of a subset of matrix metalloproteinases (MMPs) in skin from mice with IMQ-induced skin inflammation and skin from naïve mice using targeted proteomics. Our findings reveal a significant increase in the abundance of MMP-2, MMP-7, MMP-8, and MMP-13 after treatment with IMQ compared to the control skin, while MMP-3, MMP-9, and MMP-10 were exclusively detected in the IMQ-treated skin. The increased abundance and broader representation of MMPs in the IMQ-treated skin provide valuable insight into the pathophysiology of skin inflammation in the IMQ model, adding to previous studies on cytokine levels using conventional immunochemical methods. Specifically, the changes in the MMP profiles observed in the IMQ-treated skin resemble the MMP patterns found in skin lesions of individuals with psoriasis. Ultimately, the differences in MMP abundance under IMQ-induced inflammation as compared to non-inflamed control skin can be exploited as a model to investigate drug efficacy or performance of drug delivery systems.

Pathogenesis of Post-Tuberculosis Lung Disease: Defining Knowledge Gaps and Research Priorities at the Second International Post-Tuberculosis Symposium

Post-tuberculosis (post-TB) lung disease is increasingly recognized as a major contributor to the global burden of chronic lung disease, with recent estimates indicating that over half of TB survivors have impaired lung function after successful completion of TB treatment. However, the pathologic mechanisms that contribute to post-TB lung disease are not well understood, thus limiting the development of therapeutic interventions to improve long-term outcomes after TB. This report summarizes the work of the Pathogenesis and Risk Factors Committee for the Second International Post-Tuberculosis Symposium, which took place in Stellenbosch, South Africa, in April 2023. The committee first identified six areas with high translational potential: 1) tissue matrix destruction, including the role of matrix metalloproteinase dysregulation and neutrophil activity; 2) fibroblasts and profibrotic activity; 3) granuloma fate and cell death pathways; 4) mycobacterial factors, including pathogen burden; 5) animal models; and 6) the impact of key clinical risk factors, including HIV, diabetes, smoking, malnutrition, and alcohol. We share the key findings from a literature review of those areas, highlighting knowledge gaps and areas where further research is needed.

Enhancing snakebite management: The role of small molecule therapeutics in complementing antivenom strategies

The variability in snake composition presents a significant challenge in accessing an effective broad-spectrum antivenom. These highly complex mixtures can result in numerous deleterious effects affecting thousands of individuals worldwide, particularly in Asia, sub-Saharan Africa, and Latin America. While the administration of antivenom remains a recommended treatment for snakebite envenomation and is the primary means to prevent systemic damage, there are limitations concerning specificity, reversal of local effects, and economic factors that hinder the availability of these antibodies. In this review, we have compiled information on the use of small molecule therapeutics in initial first-aid treatments before antivenom administration. These enzyme inhibitors have shown promise as viable candidates to broaden our treatment approaches, simplify procedures, reduce costs, and improve the clinical outcomes of affected patients.

Improving Circulation Half-Life of Therapeutic Candidate N-TIMP2 by Unfolded Peptide Extension

Matrix metalloproteinases (MMPs) are significant drivers of many diseases, including cancer, and are established targets for drug development. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous MMP inhibitors and are being pursued for the development of anti-MMP therapeutics. TIMPs possess many attractive properties for drug candidates, such as complete MMP inhibition, low toxicity, low immunogenicity, and high tissue permeability. However, a major challenge with TIMPs is their rapid clearance from the bloodstream due to their small size. This study explores a method for extending the plasma half-life of the N-terminal domain of TIMP2 (N-TIMP2) by appending it with a long, intrinsically unfolded tail containing Pro, Ala, and Thr (PATylation). We designed and produced two PATylated N-TIMP2 constructs with tail lengths of 100 and 200 amino acids (N-TIMP2-PAT100 and N-TIMP2-PAT200). Both constructs demonstrated higher apparent molecular weights and retained high inhibitory activity against MMP-9. N-TIMP2-PAT200 significantly increased plasma half-life in mice compared to the non-PATylated variant, enhancing its therapeutic potential. PATylation offers distinct advantages for half-life extension, such as fully genetic encoding, monodispersion, and biodegradability. It can be easily applied to N-TIMP2 variants engineered for high affinity and selectivity toward individual MMPs, creating promising candidates for drug development against MMP-related diseases.

MMP9 drives ferroptosis by regulating GPX4 and iron signaling

Ferroptosis, defined by the suppression of glutathione peroxidase-4 (GPX4) and iron overload, is a distinctive form of regulated cell death. Our in-depth research identifies matrix metalloproteinase-9 (MMP9) as a critical modulator of ferroptosis through its influence on GPX4 and iron homeostasis. Employing an innovative MMP9 construct without collagenase activity, we reveal that active MMP9 interacts with GPX4 and glutathione reductase, reducing GPX4 expression and activity. Furthermore, MMP9 suppresses key transcription factors (SP1, CREB1, NRF2, FOXO3, and ATF4), alongside GPX1 and ferroptosis suppressor protein-1 (FSP1), thereby disrupting the cellular redox balance. MMP9 regulates iron metabolism by modulating iron import, storage, and export via a network of protein interactions. LC-MS/MS has identified 83 proteins that interact with MMP9 at subcellular levels, implicating them in ferroptosis regulation. Integrated pathway analysis (IPA) highlights MMP9's extensive influence on ferroptosis pathways, underscoring its potential as a therapeutic target in conditions with altered redox homeostasis and iron metabolism.

Validation of a method for the determination of Aderamastat (FP-025) in K2EDTA human plasma by LC-MS/MS

Aderamastat (FP-025) is a small molecule, selective matrix metalloproteinase (MMP)-12 inhibitor, under development for respiratory conditions which may include chronic inflammatory airway diseases and pulmonary fibrosis. To support evaluation of the pharmacokinetic parameters of Aderamastat in humans, we developed and validated a high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) analytical method for the quantification of Aderamastat in human plasma. This assay was validated in compliance with the Food and Drug Administration (FDA) Good Laboratory Practice Regulations (GLP) and European Medicines Agency (EMA) guidelines. K2EDTA human plasma samples were spiked with internal standard, processed by liquid-liquid extraction, and analyzed using reversed-phase HPLC with Turbo Ion Spray® MS/MS detection. Separation was done using a chromatographic gradient on 5 µm C6-Phenyl 110 Å, 50*2 mm analytical column at a temperature of 35 °C. The LC-MS/MS bioanalytical method, developed by QPS Taiwan to determine the concentration of Aderamastat in K2EDTA human plasma, was successfully validated with respect to linearity, sensitivity, accuracy, precision, dilution, selectivity, hemolyzed plasma, lipemic plasma, batch size, recovery, matrix effect, and carry-over. These data indicate that the method for determination of Aderamastat concentrations in human K2EDTA plasma can be used in pharmacokinetics studies and subsequent clinical trials with Aderamastat. Authors declare that, this novel data is not published and not under consideration for publication by another journal than this journal. All data will be made available on request.

MMPs as potential molecular targets in epithelial-to-mesenchymal transition driven COPD progression

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality globally and the risk of developing lung cancer is six times greater in individuals with COPD who smoke compared to those who do not smoke. Matrix metalloproteinases (MMPs) play a crucial role in the pathophysiology of respiratory diseases by promoting inflammation and tissue degradation. Furthermore, MMPs are involved in key processes like epithelial-to-mesenchymal transition (EMT), metastasis, and invasion in lung cancer. While EMT has traditionally been associated with the progression of lung cancer, recent research highlights its active involvement in individuals with COPD. Current evidence underscores its role in orchestrating airway remodeling, fostering airway fibrosis, and contributing to the potential for malignant transformation in the complex pathophysiology of COPD. The precise regulatory roles of diverse MMPs in steering EMT during COPD progression needs to be elucidated. Additionally, the less-understood aspect involves how these MMPs bi-directionally activate or regulate various EMT-associated signaling cascades during COPD progression. This review article explores recent advancements in understanding MMPs' role in EMT during COPD progression and various pharmacological approaches to target MMPs. It also delves into the limitations of current MMP inhibitors and explores novel, advanced strategies for inhibiting MMPs, potentially offering new avenues for treating respiratory diseases.

Employing comparative QSAR techniques for the recognition of dibenzofuran and dibenzothiophene derivatives toward MMP-12 inhibition

Among various matrix metalloproteinases (MMPs), MMP-12 is one of the potential targets for cancer and other diseases. However, none of the MMP-12 inhibitors has passed the clinical trials to date. Therefore, designing potential MMP-12 inhibitors as new drug molecules can provide effective therapeutic strategies for several diseases. In this study, a series of dibenzofuran and dibenzothiophene derivatives were subjected to different 2D and 3D-QSAR techniques to point out the crucial structural contributions highly influential toward the MMP-12 inhibitory activity. These techniques identified some structural attributes of these compounds that are responsible for influencing their MMP-12 inhibition. The carboxylic group may enhance proper binding with catalytic Zn2+ ion at the MMP-12 active site. Again, the i-propyl sulfonamido carboxylic acid function contributed positively toward MMP-12 inhibition. Moreover, the dibenzofuran moiety conferred stable binding at the S1' pocket for higher MMP-12 inhibition. The steric and hydrophobic groups were found favourable near the furan ring substituted at the dibenzofuran moiety. Besides these ligand-based approaches, molecular docking and molecular dynamic (MD) simulation studies not only elucidated the importance of several aspects of these MMP-12 inhibitors while disclosing the significance of the finding of these QSAR studies and their influences toward MMP-12 inhibition. The MD simulation study also revealed stable and compact binding between such compounds at the MMP-12 active site. Therefore, the findings of these validated ligand-based and structure-based molecular modeling studies can aid the development of selective and potent lead molecules that can be used for the treatment of MMP-12-associated diseases.Communicated by Ramaswamy H. Sarma.

Matrix metalloproteinase-9: A magic drug target in neuropsychiatry?

Neuropsychiatric conditions represent a major medical and societal challenge. The etiology of these conditions is very complex and combines genetic and environmental factors. The latter, for example, excessive maternal or early postnatal inflammation, as well as various forms of psychotrauma, often act as triggers leading to mental illness after a prolonged latent period (sometimes years). Matrix metalloproteinase-9 (MMP-9) is an extracellularly and extrasynaptic operating protease that is markedly activated in response to the aforementioned environmental insults. MMP-9 has also been shown to play a pivotal role in the plasticity of excitatory synapses, which, in its aberrant form, has repeatedly been implicated in the etiology of mental illness. In this conceptual review, we evaluate the experimental and clinical evidence supporting the claim that MMP-9 is uniquely positioned to be considered a drug target for ameliorating the adverse effects of environmental insults on the development of a variety of neuropsychiatric conditions, such as schizophrenia, bipolar disorder, major depression, autism spectrum disorders, addiction, and epilepsy. We also identify specific challenges and bottlenecks hampering the translation of knowledge on MMP-9 into new clinical treatments for the conditions above and suggest ways to overcome these barriers.

IGF-II regulates lysyl oxidase propeptide and mediates its effects in part via basic helix-loop-helix E40

Pulmonary fibrosis (PF) is a clinically severe and commonly fatal complication of Systemic Sclerosis (SSc). Our group has previously reported profibrotic roles for Insulin-like Growth Factor II (IGF-II) and Lysyl Oxidase (LOX) in SSc-PF. We sought to identify downstream regulatory mediators of IGF-II. In the present work, we show that SSc lung tissues have higher baseline levels of the total (N-glycosylated/unglycosylated) LOX-Propeptide (LOX-PP) than control lung tissues. LOX-PP-mediated changes were consistent with the extracellular matrix (ECM) deregulation implicated in SSc-PF progression. Furthermore, Tolloid-like 1 (TLL1) and Bone Morphogenetic Protein 1 (BMP1), enzymes that can cleave ProLOX to release LOX-PP, were increased in SSc lung fibrosis and the bleomycin (BLM)-induced murine lung fibrosis model, respectively. In addition, IGF-II regulated the levels of ProLOX, active LOX, LOX-PP, BMP1, and isoforms of TLL1. The Class E Basic Helix-Loop-Helix protein 40 (BHLHE40) transcription factor localized to the nucleus in response to IGF-II. BHLHE40 silencing downregulated TLL1 isoforms and LOX-PP, and restored features of ECM deregulation triggered by IGF-II. Our findings indicate that IGF-II, BHLHE40, and LOX-PP may serve as targets of therapeutic intervention to halt SSc-PF progression.

The host protease KLK5 primes and activates spike proteins to promote human betacoronavirus replication and lung inflammation

Coronaviruses rely on host proteases to activate the viral spike protein, which facilitates fusion with the host cell membrane and the release of viral genomic RNAs into the host cell cytoplasm. The distribution of specific host proteases in the host determines the host, tissue, and cellular tropism of these viruses. Here, we identified the kallikrein (KLK) family member KLK5 as a major host protease secreted by human airway cells and exploited by multiple human betacoronaviruses. KLK5 cleaved both the priming (S1/S2) and activation (S2') sites of spike proteins from various human betacoronaviruses in vitro. In contrast, KLK12 and KLK13 displayed preferences for either the S2' or S1/S2 site, respectively. Whereas KLK12 and KLK13 worked in concert to activate SARS-CoV-2 and MERS-CoV spike proteins, KLK5 by itself efficiently activated spike proteins from several human betacoronaviruses, including SARS-CoV-2. Infection of differentiated human bronchial epithelial cells (HBECs) with human betacoronaviruses induced an increase in KLK5 that promoted virus replication. Furthermore, ursolic acid and other related plant-derived triterpenoids that inhibit KLK5 effectively suppressed the replication of SARS-CoV, MERS-CoV, and SARS-CoV-2 in HBECs and mitigated lung inflammation in mice infected with MERS-CoV or SARS-CoV-2. We propose that KLK5 is a pancoronavirus host factor and a promising therapeutic target for current and future coronavirus-induced diseases.