Membrane Type-1 Matrix Metalloproteinase Research Articles

Paradoxical Changes: EMMPRIN Tissue and Plasma Levels in Marfan Syndrome-Related Thoracic Aortic Aneurysms.

Background: Thoracic aortic aneurysms (TAAs) associated with Marfan syndrome (MFS) are unique in that extracellular matrix metalloproteinase inducer (EMMPRIN) levels do not behave the way they do in other cardiovascular pathologies. EMMPRIN is shed into the circulation through the secretion of extracellular vesicles. This has been demonstrated to be dependent upon the Membrane Type-1 MMP (MT1-MMP). We investigated this relationship in MFS TAA tissue and plasma to discern why unique profiles may exist. Methods: Protein targets were measured in aortic tissue and plasma from MFS patients with TAAs and were compared to healthy controls. The abundance and location of MT1-MMP was modified in aortic fibroblasts and secreted EMMPRIN was measured in conditioned culture media. Results: EMMPRIN levels were elevated in MFS TAA tissue but reduced in plasma, compared to the controls. Tissue EMMPRIN elevation did not induce MMP-3, MMP-8, or TIMP-1 expression, while MT1-MMP and TIMP-2 were elevated. MMP-2 and MMP-9 were reduced in TAA tissue but increased in plasma. In aortic fibroblasts, EMMPRIN secretion required the internalization of MT1-MMP. Conclusions: In MFS, impaired EMMPRIN secretion likely contributes to higher tissue levels, influenced by MT1-MMP cellular localization. Low EMMPRIN levels, in conjunction with other MMP analytes, distinguished MFS TAAs from controls, suggesting diagnostic potential.

Functional Roles of Furin in Cardio-Cerebrovascular Diseases.

Furin plays a major role in post-translational modification of several biomolecules, including endogenous hormones, growth factors, and cytokines. Recent reports have demonstrated the association of furin and cardio-cerebrovascular diseases (CVDs) in humans. This review describes the possible pathogenic contribution of furin and its substrates in CVDs. Early-stage hypertension and diabetes mellitus show a negative correlation with furin. A reduction in furin might promote hypertension by decreasing maturation of B-type natriuretic peptide (BNP) or by decreasing shedding of membrane (pro)renin receptor (PRR), which facilitates activation of the renin-angiotensin-aldosterone system (RAAS). In diabetes, furin downregulation potentially leads to insulin resistance by reducing maturation of the insulin receptor. In contrast, the progression of other CVDs is associated with an increase in furin, including dyslipidemia, atherosclerosis, ischemic stroke, myocardial infarction (MI), and heart failure. Upregulation of furin might promote maturation of membrane type 1-matrix metalloproteinase (MT1-MMP), which cleaves low-density lipoprotein receptor (LDLR), contributing to dyslipidemia. In atherosclerosis, elevated levels of furin possibly enhance maturation of several substrates related to inflammation, cell proliferation, and extracellular matrix (ECM) deposition and degradation. Neuronal cell death following ischemic stroke has also been shown to involve furin substrates (e.g., MT1-MMP, hepcidin, and hemojuvelin). Moreover, furin and its substrates, including tumor necrosis factor-α (TNF-α), endothelin-1 (ET-1), and transforming growth factor-β1 (TGF-β1), are capable of mediating inflammation, hypertrophy, and fibrosis in MI and heart failure. Taken together, this evidence provides functional significance of furin in CVDs and might suggest a potential novel therapeutic modality for the management of CVDs.

Comparative analysis of matrix metalloproteinases by zymography in patients with colorectal carcinoma.

Zymography is an electrophoretic method in which proteins are separated in a polyacrylamide gel in the presence of sodium dodecyl sulfate (SDS-PAGE). This method is used for the detection of enzymatic activity and molecular characterization of proteins. In contrast to the standard SDS-PAGE method, a substrate is incorporated into the gel during zymography, which is subsequently cleaved by target proteases. Many studies have focused on the development and progression of inflammatory diseases affecting the gastrointestinal tract, emphasizing the role of the largest group of proteases, matrix metalloproteinases (MMPs). The most used classification of this group of enzymes (by researchers in MMP biology) is based in part on the historical evaluation of the substrate specificity of MMPs and in part on the cellular localization of MMPs. MMPs are thus classified into the groups of collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs (MT-MMPs), and others. An important group of MMPs are gelatinases which are involved in the breakdown of collagen type IV and gelatin of extracellular matrix and participate in the regulation of various physiological or pathological processes such as morphogenesis, angiogenesis, tissue repair, cirrhosis, arthritis, and metastasis. The present study's objective was to determine the amount of active MMP-9 and MMP-2 forms in tissue samples using zymography. The patient group was according to histology findings divided into the benign tumor (control) group (8 patients), and the malignant tumor group (24 patients). The respondents in the malignant tumor group were further divided according to the standard TNM classification. The results of this study confirmed that MMP-2, unlike MMP-9, can be used as a prognostic biomarker of CRC, because only the expression of active MMP-2 confirmed statistically significant differences between individual stages of CRC. Moreover, MMP-2 seems to play a more important role in higher stages of CRC. Substantial disparities in the determination of active MMPs between the observed groups support the assumption for the integration of zymography into clinical diagnostics of CRC together with molecular and other studies.

Analysis of Matrix Metalloproteinase Activity and Inhibition in Cancer Spheroids.

The utilization of tumor spheroids and organoids has greatly facilitated mechanistic understanding of tumor growth and invasion and lead to more effective high-throughput analysis of potential chemotherapeutic agents. In spheroid and organoid systems, tumor invasion occurs in three dimensions and monitoring this behavior can be data intensive. Quantitative correlation of tumor invasion with protease activity can further exacerbate data storage issues. The present method utilizes the "Hit Pick" approach to provide quantitative analysis and correlation of tumor invasion and membrane type 1 matrix metalloproteinase (MT1-MMP) activity in a rapid fashion with greatly reduced data storage requirements compared with standard image analysis approaches. Inhibition of MT1-MMP activity in spheroids can also be monitored by the present approach.

Simvastatin induces degradation of the extracellular matrix in human leiomyomata: novel in vitro, in vivo, and patient level evidence of matrix metalloproteinase involvement

ObjectivesTo assess the effect of simvastatin on uterine leiomyoma growth and extracellular matrix (ECM) deposition. DesignLaboratory analysis of human leiomyoma cell culture, xenograft in a mouse model, and patient tissue from a clinical trial. SettingAcademic research center. Patient(s)Tissue culture from human leiomyoma tissue and surgical leiomyoma tissue sections from a placebo-controlled randomized clinical trial. Intervention(s)Simvastatin treatment. Main Outcome Measure(s)Serum concentrations, xenograft volumes, and protein expression. ResultsMice xenografted with 3-dimensional human leiomyoma cultures were divided as follows: 7 untreated controls, 12 treated with activated simvastatin at 10 mg/kg body weight, and 15 at 20 mg/kg body weight. Simvastatin was detected in serum from mice injected at the highest dose. Xenograft volumes were significantly smaller (mean 53% smaller at the highest concentration, p < 0.05). There was dissolution of compact ECM, decreased ECM formation, and lower collagen protein expression in xenografts. Membrane type 1 matrix metalloproteinase (MT1-MMP) was increased in vitro and in vivo. Matrix metalloproteinase 2 (MMP2) and low density lipoprotein receptor related protein 1 (LRP1) were increased in vitro. ConclusionsSimvastatin exhibited antitumoral activity, with extracellular matrix degradation and decreased leiomyoma tumor volume in vivo. Activation of the MMP2/MT1-MMP/LRP1 pathway may explain these findings.

Analysis of Membrane Type-1 Matrix Metalloproteinase (MT1-MMP, MMP14) in Eutopic and Ectopic Endometrium and in Serum and Endocervical Mucus of Endometriosis.

Membrane type-matrix metalloproteinases (MT-MMPs) are a subgroup of the matrix metalloproteinases (MMPs) family and are key molecules in the degradation of the extracellular matrix. Membrane type-1 matrix metalloproteinase (MT1-MMP, MMP14) is often deregulated in different cancer tissues and body fluids of human cancer patients; however, MT1-MMP levels in endometriosis and adenomyosis patients are currently unknown. Tissue samples from patients with and without endometriosis or adenomyosis were analyzed with immunohistochemistry for the localization of MT1-MMP. Serum and endocervical mucus samples from patients with and without endometriosis or adenomyosis were investigated with MT1-MMP ELISAs. MT1-MMP was localized preferentially in the glands of eutopic and ectopic endometrium. MT1-MMP protein levels are significantly reduced in ovarian endometriosis (HSCORE = 31) versus eutopic endometrium (HSCORE = 91) and adenomyosis (HSCORE = 149), but significantly increased in adenomyosis (HSCORE = 149) compared to eutopic endometrium (HSCORE = 91). Similarly, analysis of the levels of MT1-MMP using enzyme-linked immune assays (ELISAs) demonstrated a significant increase in the concentrations of MT1-MMP in the serum of endometriosis patients (1.3 ± 0.8) versus controls (0.7 ± 0.2), but not in the endocervical mucus. Furthermore, MT1-MMP levels in the endocervical mucus of patients with endometriosis were notably reduced in patients using contraception (3.2 ± 0.4) versus those without contraception (3.8 ± 0.2). Taken together, our findings showed an opposite regulation of MT1-MMP in the tissue of ovarian endometriosis and adenomyosis compared to eutopic endometrium without endometriosis but increased serum levels in patients with endometriosis.

MT1-MMP as a Key Regulator of Metastasis.

Membrane type1-matrix metalloproteinase (MT1-MMP) is a member of metalloproteinases that is tethered to the transmembrane. Its major function in cancer progression is to directly degrade the extracellular matrix components, which are mainly type I-III collagen or indirectly type IV collagen through the activation of MMP-2 with a cooperative function of the tissue inhibitor of metalloproteinase-2 (TIMP-2). MT1-MMP is expressed as an inactive form (zymogen) within the endoplasmic reticulum (ER) and receives truncation processing via furin for its activation. Upon the appropriate trafficking of MT1-MMP from the ER, the Golgi apparatus to the cell surface membrane, MT1-MMP exhibits proteolytic activities to the surrounding molecules such as extracellular matrix components and cell surface molecules. MT1-MMP also retains a non-proteolytic ability to activate hypoxia-inducible factor 1 alpha (HIF-1A) via factors inhibiting the HIF-1 (FIH-1)-Mint3-HIF-1 axis, resulting in the upregulation of glucose metabolism and oxygen-independent ATP production. Through various functions of MT1-MMP, cancer cells gain motility on migration/invasion, thus causing metastasis. Despite the long-time efforts spent on the development of MT1-MMP interventions, none have been accomplished yet due to the side effects caused by off-target effects. Recently, MT1-MMP-specific small molecule inhibitors or an antibody have been reported and these inhibitors could potentially be novel agents for cancer treatment.

Abstract P1047: The Extracellular Matrix Metalloproteinase Inducer And The Membrane Type 1 Matrix Metalloproteinase In Marfan Syndrome Related Thoracic Aortic Aneurysm

Objectives: Marfan Syndrome (MFS) is a connective tissue disorder commonly associated with Thoracic Aortic Aneurysms (TAAs). TAAs occur because of abnormal remodeling of the aortic extracellular matrix (ECM). The balance between matrix metalloproteinases (MMPs) and the Tissue Inhibitors of MMPs (TIMPs), regulates these processes. The extracellular MMP inducer (EMMPRIN), is a widely expressed glycoprotein capable of stimulating the production of various MMPs, suggesting a direct role in driving pathology. The Membrane Type-1 MMP (MT1-MMP) can cause proteolytic shedding of EMMPRIN. Therefore, we investigated this relationship in MFS TAA tissue and plasma and tested the hypothesis that a unique proteolytic profile may exist. Methods: Levels of EMMPRIN, MT1-MMP, MMP-2, MMP-9, MMP-3, MMP-8, TIMP-1, and TIMP-2 were measured in aortic tissue and plasma from MFS patients with TAA and compared to healthy controls. Following modification of the abundance and location of MT1-MMP in isolated primary aortic fibroblasts, secreted EMMPRIN was measured in conditioned culture media. Results: Compared to controls, EMMPRIN is elevated in MFS TAA tissue and reduced in the plasma. Elevation of EMMPRIN abundance in tissue does not induce MMP-3, MMP-8, or TIMP-1 expression. MT1-MMP and TIMP-2 are elevated in MFS TAA tissue. MMP-2 and MMP-9 are reduced in MFS TAA tissue while increased in the plasma. In aortic fibroblasts we found that MT1-MMP must be internalized from the plasma membrane for EMMPRIN secretion. Conclusions: Our findings indicate that the pathological consequences of MFS cause the shedding of EMMPRIN and its secretion from cells to be blocked, which leads to higher EMPRINN abundance in MFS TAA tissue. This process depends upon the cellular location of MT1-MMP. Taken together, these observations suggest that internalization of MT1-MMP from the plasma membrane is required for the cellular secretion of EMMPRIN from aortic fibroblasts.

Matrix Metalloproteinases Inhibitors in Cancer Treatment: An Updated Review (2013-2023).

Matrix metalloproteinases (MMPs) are identifiable members of proteolytic enzymes that can degrade a wide range of proteins in the extracellular matrix (ECM). MMPs can be categorized into six groups based on their substrate specificity and structural differences: collagenases, gelatinases, stromelysins, matrilysins, metalloelastase, and membrane-type MMPs. MMPs have been linked to a wide variety of biological processes, such as cell transformation and carcinogenesis. Over time, MMPs have been evaluated for their role in cancer progression, migration, and metastasis. Accordingly, various MMPs have become attractive therapeutic targets for anticancer drug development. The first generations of broad-spectrum MMP inhibitors displayed effective inhibitory activities but failed in clinical trials due to poor selectivity. Thanks to the evolution of X-ray crystallography, NMR analysis, and homology modeling studies, it has been possible to characterize the active sites of various MMPs and, consequently, to develop more selective, second-generation MMP inhibitors. In this review, we summarize the computational and synthesis approaches used in the development of MMP inhibitors and their evaluation as potential anticancer agents.

Vimentin-mediated myosin 10 aggregation at tips of cell extensions drives MT1-MMP-dependent collagen degradation in colorectal cancer.

Colorectal cancer (CRC) is a high prevalence adenocarcinoma with progressive increases in metastasis-related mortality, but the mechanisms governing the extracellular matrix (ECM) degradation important for metastasis in CRC are not well-defined. We investigated a functional relationship between vimentin (Vim) and myosin 10 (Myo10), and whether this relationship is associated with cancer progression. We tested the hypothesis that Vim regulates the aggregation of Myo10 at the tips of cell extensions, which increases membrane-type 1 matrix metalloproteinase (MT1-MMP)-associated local collagen proteolysis and ECM degradation. Analysis of CRC samples revealed colocalization of Vim with Myo10 and MT1-MMP in cell extensions adjacent to sites of collagen degradation, suggesting an association with local cell invasion. We analyzed cultured CRC cells and fibroblasts and found that Vim accelerates aggregation of Myo10 at cell tips, which increases the cell extension rate. Vim stabilizes the interaction of Myo10 with MT1-MMP, which in turn increases collagenolysis. Vim depletion reduced the aggregation of Myo10 at the cell extension tips and MT1-MMP-dependent collagenolysis. We propose that Vim interacts with Myo10, which in turn associates with MT1-MMP to facilitate the transport of these molecules to the termini of cell extensions and there enhance cancer invasion of soft connective tissues.

Molecular Mechanisms Driven by MT4-MMP in Cancer Progression.

MT4-MMP (or MMP-17) belongs to the membrane-type matrix metalloproteinases (MT-MMPs), a distinct subset of the MMP family that is anchored to the cell surface, in this case by a glycosylphosphatidylinositol (GPI) motif. Its expression in a variety of cancers is well documented. However, the molecular mechanisms by which MT4-MMP contributes to tumor development need further investigation. In this review, we aim to summarize the contribution of MT4-MMP in tumorigenesis, focusing on the molecular mechanisms triggered by the enzyme in tumor cell migration, invasiveness, and proliferation, in the tumor vasculature and microenvironment, as well as during metastasis. In particular, we highlight the putative substrates processed and signaling cascades activated by MT4-MMP that may underlie these malignancy processes and compare this with what is known about its role during embryonic development. Finally, MT4-MMP is a relevant biomarker of malignancy that can be used for monitoring cancer progression in patients as well as a potential target for future therapeutic drug development.

Degradomic Identification of Membrane Type 1-Matrix Metalloproteinase as an ADAMTS9 and ADAMTS20 Substrate

The secreted metalloproteases ADAMTS9 and ADAMTS20 are implicated in extracellular matrix proteolysis and primary cilium biogenesis. Here, we show that clonal gene-edited RPE-1 cells in which ADAMTS9 was inactivated, and which constitutively lack ADAMTS20 expression, have morphologic characteristics distinct from parental RPE-1 cells. To investigate underlying proteolytic mechanisms, a quantitative terminomics method, terminal amine isotopic labeling of substrates was used to compare the parental and gene-edited RPE-1 cells and their medium to identify ADAMTS9 substrates. Among differentially abundant neo-amino (N) terminal peptides arising from secreted and transmembrane proteins, a peptide with lower abundance in the medium of gene-edited cells suggested cleavage at the Tyr314-Gly315 bond in the ectodomain of the transmembrane metalloprotease membrane type 1-matrix metalloproteinase (MT1-MMP), whose mRNA was also reduced in gene-edited cells. This cleavage, occurring in the MT1-MMP hinge, that is, between the catalytic and hemopexin domains, was orthogonally validated both by lack of an MT1-MMP catalytic domain fragment in the medium of gene-edited cells and restoration of its release from the cell surface by reexpression of ADAMTS9 and ADAMTS20 and was dependent on hinge O-glycosylation. A C-terminally semitryptic MT1-MMP peptide with greater abundance in WT RPE-1 medium identified a second ADAMTS9 cleavage site in the MT1-MMP hemopexin domain. Consistent with greater retention of MT1-MMP on the surface of gene-edited cells, pro-MMP2 activation, which requires cell surface MT1-MMP, was increased. MT1-MMP knockdown in gene-edited ADAMTS9/20-deficient cells restored focal adhesions but not ciliogenesis. The findings expand the web of interacting proteases at the cell surface, suggest a role for ADAMTS9 and ADAMTS20 in regulating cell surface activity of MT1-MMP, and indicate that MT1-MMP shedding does not underlie their observed requirement in ciliogenesis.

Abstract 2757: Combination of a fluorescent substrate-based MMP activity assay and hit pick reading/imaging procedure to screen for inhibitors of MT1-MMP activity and 3D glioma tumoroid invasion

Abstract Malignant and nonmalignant brain tumors are composed of a group of more than 100 different types. Malignant gliomas, including glioblastoma multiforme (GBM) and astrocytomas, are the most common primary brain tumors in the United States, and make up 78% of malignant brain tumors. Membrane type 1 matrix metalloproteinase (MT1-MMP) has been shown to be crucial for the progression, invasion, migration, and angiogenesis of tumors. Use of a FRET substrate to quantify MT1-MMP activity, where tumoroids are embedded in a collagen hydrogel, would simplify detection of potential protease inhibitors, while using an in vivo-like cell model. In the present study, multiple glioma cell lines were formed into tumor spheroids, followed by type I collagen addition. Many known MT1-MMP inhibitors were then added to the wells, to potentially inhibit invasion of the 3D cell models. The substrate and experimental setup were then combined with the joint reading and imaging process available in the Agilent BioTek Gen5 microplate reader and imager software, to create a hit pick screening method. During the procedure, all control and test wells were read, and the signal from cleaved substrate was quantified. Uninhibited invasion within positive control wells exhibited high fluorescence values. Therefore, a hit pick criterion was established such that any wells containing test molecules that were statistically lower than average in fluorescent signal from the corresponding positive control, which should exhibit inhibited invasion, were imaged. Wells that were not significantly lower were not imaged. The result was a screening method which increased efficiency by reducing image capture time and storage requirements. Citation Format: Brad Larson, Gregg Fields, Ania Knapinska. Combination of a fluorescent substrate-based MMP activity assay and hit pick reading/imaging procedure to screen for inhibitors of MT1-MMP activity and 3D glioma tumoroid invasion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2757.

Potential for Predicting Lymph-node Metastasis in Invasive Breast Carcinoma of No Special Type Using MT1-MMP Immunohistochemistry Staining

BACKGROUND: Lymph-node metastasis (LNM) is the most frequent complication of invasive breast carcinoma (IBC). AIM: Using immunohistochemistry (IHC), this study aims to determine the role of membrane-type 1-matrix metalloproteinase (MT1-MMP) expression as a biomarker for LNM in IBC of no special type (IBC-NST). MATERIALS AND METHODS: Primary tumors from individuals with IBC-NST were preserved in paraffin and then categorized as having LNM or not. Tumor size, lymphovascular invasion (LVI), tumor grade, MT1-MMP expression, and other factors were evaluated across a range of ages. MT1-MMP expression was assessed by IHC, with supplemental data acquired from archives. Collecting and analyzing the data required the use of both bivariate and multivariate techniques. RESULTS: The odds ratio (OR) for LNM was 5.003 (95% CI: 1.68–20.61) for MT1-MMP expression, while the OR for LVI was 4.71 (95% CI: 1.57–18.8). These associations were found using the Firth penalized likelihood Logit analysis method. At an H-score cutoff of 202.22 (70.8% sensitivity and 95.8% specificity), an area under the receiver operating characteristic of 0.9130.038 (95% CI: 0.838–0.989) was found for MT1-MMP expression in diagnosing LNM. CONCLUSION: In conjunction with LVI, MT1-MMP expression may serve as a predictor of LNM. To further assist data separation in future research, the MT1-MMP expression H-score cutoff of 202.22 could be used.

Tumour Suppressor Neuron Navigator 3 and Matrix Metalloproteinase 14 are Co-expressed in Most Melanomas but Downregulated in Thick Tumours.

Melanoma is a highly metastatic tumour originating from neural crest-derived melanocytes. The aim of this study was to analyse the expression of neuron navigator 3 (NAV3) in relation to membrane type-1 matrix metalloproteinase MMP14, a major regulator of invasion, in 40 primary melanomas, 15 benign naevi and 2 melanoma cell lines. NAV3 copy number changes were found in 18/27 (67%) primary melanomas, so that deletions dominated (16/27 of samples, 59%). NAV3 protein was found to be localized at the leading edge of migrating melanoma cells in vitro. Silencing of NAV3 reduced both melanoma cell migration in 2-dimensional conditions, as well as sprouting in 3-dimensional collagen I. NAV3 protein expression correlated with MMP14 in 26/37 (70%) primary melanomas. NAV3 and MMP14 were co-expressed in all tumours with Breslow thickness < 1 mm, in 11/23 of mid-thickness tumours (1-5 mm), but in only 1/6 samples of thick (> 5 mm) melanomas. Altogether, NAV3 number changes are frequent in melanomas, and NAV3 and MMP14, while expressed in all thin melanomas, are often downregulated in thicker tumours, suggesting that the lack of both NAV3 and MMP14 favours melanoma progression.

Screening MT1-MMP Activity and Inhibition in Three-Dimensional Tumor Spheroids

Membrane type 1 matrix metalloproteinase (MT1-MMP) has been shown to be crucial for tumor angiogenesis, invasion, and metastasis, and thus MT1-MMP is a high priority target for potential cancer therapies. To properly evaluate MT1-MMP inhibitors, a screening protocol is desired by which enzyme activity can be quantified in a tumor microenvironment-like model system. In the present study, we applied a fluorogenic, collagen model triple-helical substrate to quantify MT1-MMP activity for tumor spheroids embedded in a collagen hydrogel. The substrate was designed to be MT1-MMP selective and to possess fluorescent properties compatible with cell-based assays. The proteolysis of the substrate correlated to glioma spheroid invasion. In turn, the application of either small molecule or protein-based MMP inhibitors reduced proteolytic activity and glioma spheroid invasion. The presence of MT1-MMP in glioma spheroids was confirmed by western blotting. Thus, spheroid invasion was dependent on MT1-MMP activity, and inhibitors of MT1-MMP and invasion could be conveniently screened in a high-throughput format. The combination of the fluorogenic, triple-helical substrate, the three-dimensional tumor spheroids embedded in collagen, and Hit-Pick software resulted in an easily adaptable in vivo-like tumor microenvironment for rapidly processing inhibitor potential for anti-cancer use.

Mint3 as a Potential Target for Cooling Down HIF-1α-Mediated Inflammation and Cancer Aggressiveness.

Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that plays a crucial role in cells adapting to a low-oxygen environment by facilitating a switch from oxygen-dependent ATP production to glycolysis. Mediated by membrane type-1 matrix metalloproteinase (MT1-MMP) expression, Munc-18-1 interacting protein 3 (Mint3) binds to the factor inhibiting HIF-1 (FIH-1) and inhibits its suppressive effect, leading to HIF-1α activation. Defects in Mint3 generally lead to improved acute inflammation, which is regulated by HIF-1α and subsequent glycolysis, as well as the suppression of the proliferation and metastasis of cancer cells directly through its expression in cancer cells and indirectly through its expression in macrophages or fibroblasts associated with cancer. Mint3 in inflammatory monocytes enhances the chemotaxis into metastatic sites and the production of vascular endothelial growth factors, which leads to the expression of E-selectin at the metastatic sites and the extravasation of cancer cells. Fibroblasts express L1 cell adhesion molecules in a Mint3-dependent manner and enhance integrin-mediated cancer progression. In pancreatic cancer cells, Mint3 directly promotes cancer progression. Naphthofluorescein, a Mint3 inhibitor, can disrupt the interaction between FIH-1 and Mint3 and potently suppress Mint3-mediated inflammation, cancer progression, and metastasis without causing marked adverse effects. In this review, we will introduce the potential of Mint3 as a therapeutic target for inflammatory diseases and cancers.

Altered host protease determinants for SARS-CoV-2 Omicron.

Successful severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection requires proteolytic cleavage of the viral spike protein. While the role of the host transmembrane protease serine 2 in SARS-CoV-2 infection is widely recognized, the involvement of other proteases capable of facilitating SARS-CoV-2 entry remains incompletely explored. Here, we show that multiple members from the membrane-type matrix metalloproteinase (MT-MMP) and a disintegrin and metalloproteinase families can mediate SARS-CoV-2 entry. Inhibition of MT-MMPs significantly reduces SARS-CoV-2 replication in vitro and in vivo. Mechanistically, we show that MT-MMPs can cleave SARS-CoV-2 spike and angiotensin-converting enzyme 2 and facilitate spike-mediated fusion. We further demonstrate that Omicron BA.1 has an increased efficiency on MT-MMP usage, while an altered efficiency on transmembrane serine protease usage for virus entry compared with that of ancestral SARS-CoV-2. These results reveal additional protease determinants for SARS-CoV-2 infection and enhance our understanding on the biology of coronavirus entry.

Effects of riboflavin/ultraviolet-A scleral collagen cross-linking on regional scleral thickness and expression of MMP-2 and MT1-MMP in myopic guinea pigs.

To investigate the effects of scleral collagen cross-linking (SXL) using riboflavin and ultraviolet A (UVA) light on the scleral thickness of different regions and expression of matrix metalloproteinase 2 (MMP-2) and membrane-type MMP-1 (MT1-MMP) in guinea pigs with lens-induced myopia. Forty-eight 4-week-old guinea pigs were assigned to three groups (n = 16 per group): SXL group, lens-induced myopia (LIM) group, and control group. The sclera of the right eye of the guinea pig in the SXL group was surgically exposed, riboflavin was dropped on the treatment area for 10 minutes before the 30-minute UVA irradiation. The same surgical procedure was performed in the LIM group without UVA irradiation. The -10.00 D lenses were then placed on the right eyes of guinea pigs in the SXL and LIM groups for six weeks. The control group received no treatment. The left eyes were untreated in all groups. The ocular axial length (AXL) and refraction were measured at 4 weeks and 10 weeks of age. 10-week-old guinea pigs were sacrificed, and the right eyes were enucleated and evenly divided for preparation of hematoxylin and eosin (HE) stained sections, quantitative real-time polymerase chain reaction (qPCR) and western blotting. The scleral thickness of different regions was measured on HE stained sections. The temporal half of the sclera was harvested to measure the expression of MMP-2 and MT1-MMP by qPCR and western blotting. The AXL was significantly shorter, and the degree of myopic refraction was significantly lower in the SXL group than those in the LIM group at 10 weeks of age. The scleral thickness of the cross-linked area was significantly greater in the SXL group than that of the corresponding area in the LIM group, while the scleral thickness of the untreated nasal side was not significantly different between the SXL group and the LIM group. The expression of MMP-2 and MT1-MMP of the cross-linked sclera was significantly downregulated compared with that of the corresponding area in the LIM group. Riboflavin/UVA SXL could slow myopia progression and thicken the cross-linked sclera in guinea pigs, which might be related to the downregulation of MMP-2 and MT1-MMP expression during the scleral remodeling process.

Highly water-soluble diacetyl chrysin ameliorates diabetes-associated renal fibrosis and retinal microvascular abnormality in db/db mice.

Chronic or intermittent hyperglycemia is associated with the development of diabetic complications. Oxidative stress and inflammation can be altered by hyperglycemia in diverse tissues, including kidneys and eyes, and play a pivotal role in diabetic complications. Our previous studies showed that the water-insoluble 5,7-dihydroxyflvone chrysin effectively combats diabetic damages incurred in diabetic kidneys and retinas. The current study employed the newly-synthesized 5.7-di-O-acetylchrysin, having higher solubility than chrysin, to compare the effects on diabetes-associated renal fibrosis and abnormal retinal neovascularization. In the in vivo study, db/db mice as animal models of type 2 diabetes were orally administrated 10 mg/kg BW diacetylchrysin, daily for 10 weeks. Unlike chrysin, oral administration of 10 mg/kg diacetylchrysin did not lower the blood glucose level and 24 h urine volume in db/db mice. Nevertheless, the urinary albumin excretion was markedly reduced. The administration of diacetylchrysin also diminished the deposition of collagen fibers in diabetic glomeruli and tubules by suppressing the induction of connective tissue growth factor and collagen IV in diabetic kidneys. Supplying diacetylchrysin enhanced the membrane type-1 matrix metalloproteinase (MMP) expression reduced in diabetic kidneys, while the tissue inhibitor of MMP-2 induction was attenuated in diacetylchrysin-challenged diabetic kidneys. In addition, supplementing diacetylchrysin to diabetic mice ameliorated renal injury due to glomerulosclerosis and tubular interstitial fibrosis. Furthermore, the reduced retinal inductions of Zonula occludens-1 and vascular endothelial cadherin in db/db mice were elevated in the retinal tissues of diacetylchrysin-treated animals. Oral administration of diacetylchrysin curtailed the induction of vascular endothelial growth factor (VEGF) and VEGF receptor 2 in db/db mice, ultimately retarding diabetes-associated retinal neovascularization. Additionally, the retinal formation of acellular capillaries with leaky vessels was reduced in diacetylchrysin-treated db/db mice. Diacetylchrysin may act as a potent pro-health agent for treating renal fibrosis-associated diabetic nephropathy and retinal neovascularization-associated diabetic retinopathy.