Cancer cell extravasation requires iplectin-mediated delivery of MT1-MMP at invadopodia.

BACKGROUND: Invadopodia facilitate cancer cell extravasation, but the molecular mechanism whereby invadopodia-specific proteases such as MT1-MMP are called to invadopodia is unclear. METHODS: Mass spectrometry and immunoprecipitation were used to identify interactors of MT1-MMP in metastatic breast cancer cells. After identification, siRNA and small molecule inhibitors were used to assess the effect these interactors had on cellular invasiveness. The chicken embryo chorioallantoic membrane (CAM) model was used to assess extravasation and invadopodia formation in vivo. RESULTS: In metastatic breast cancer cells, MT1-MMP was found to associate with plectin, a cytolinker and scaffolding protein. Complex formation between plectin and MT1-MMP launches invadopodia formation, a subtype we termed iplectin (i = invadopodial). iPlectin delivers MT1-MMP to invadopodia and is indispensable for regulating cell surface levels of the enzyme. Genetic depletion of plectin with siRNA reduced invadopodia formation and cell invasion in vitro. In vivo extravasation efficiency assays and intravital imaging revealed iplectin to be a key contributor to invadopodia ultrastructure and essential for extravasation. Pharmacologic inhibition of plectin using the small molecule Plecstatin-1 (PST-1) abrogated MT1-MMP delivery to invadopodia and extravasation efficiency. CONCLUSIONS: Anti-metastasis therapeutic approaches that target invadopodia are possible by disrupting interactions between MT1-MMP and iplectin. CLINICAL TRIAL REGISTRATION NUMBER: NCT04608357.

Mmp14-dependent remodeling of the pericellular-dermal collagen interface governs fibroblast survival.

Dermal fibroblasts deposit type I collagen, the dominant extracellular matrix molecule found in skin, during early postnatal development. Coincident with this biosynthetic program, fibroblasts proteolytically remodel pericellular collagen fibrils by mobilizing the membrane-anchored matrix metalloproteinase, Mmp14. Unexpectedly, dermal fibroblasts in Mmp14-/- mice commit to a large-scale apoptotic program that leaves skin tissues replete with dying cells. A requirement for Mmp14 in dermal fibroblast survival is recapitulated in vitro when cells are embedded within, but not cultured atop, three-dimensional hydrogels of crosslinked type I collagen. In the absence of Mmp14-dependent pericellular proteolysis, dermal fibroblasts fail to trigger ß1 integrin activation and instead actuate a TGF-ß1/phospho-JNK stress response that leads to apoptotic cell death in vitro as well as in vivo. Taken together, these studies identify Mmp14 as a requisite cell survival factor that maintains dermal fibroblast viability in postnatal dermal tissues.

The novel prognostic marker SPOCK2 regulates tumour progression in melanoma.

Secreted protein acidic and cysteine rich/osteonectin, cwcv and kazal-like domain proteoglycan 2 (SPOCK2) is a protein that regulates cell differentiation and growth. Recent studies have reported that SPOCK2 plays important roles in the progression of various human cancers; however, the role of SPOCK2 in melanoma remains unknown. Therefore, this study investigated the roles of SPOCK2 and the related mechanisms in melanoma progression. To evaluate the clinical significance of SPOCK2 expression in patients with melanoma, we analysed the association between SPOCK2 expression and its prognostic value for patients with melanoma using systematic multiomic analysis. Subsequently, to investigate the roles of Spock2 in melanoma progression in vitro and in vivo, we knocked down Spock2 in the B16F10 melanoma cell line. High SPOCK2 levels were positively associated with good prognosis and long survival rate of patients with melanoma. Spock2 knockdown promoted melanoma cell proliferation by inducing the cell cycle and inhibiting apoptosis. Moreover, Spock2 downregulation significantly increased cell migration and invasion by upregulating MMP2 and MT1-MMP. The increased cell proliferation and migration were inhibited by MAPK inhibitor, and ERK phosphorylation was considerably enhanced in Spock2 knockdown cells. Therefore, Spock2 could function as a tumour suppressor gene to regulate melanoma progression by regulating the MAPK/ERK signalling pathway. Additionally, Spock2 knockdown cell injection induced considerable tumour growth and lung metastasis in C57BL6 mice compared to that in the control group. Our findings suggest that SPOCK2 plays crucial roles in malignant progression of melanoma and functions as a novel therapeutic target of melanoma.

Basement membrane-related MMP14 predicts poor prognosis and response to immunotherapy in bladder cancer.

BACKGROUND: Basement membrane (BM) is an important component of the extracellular matrix, which plays an important role in the growth and metastasis of tumor cells. However, few biomarkers based on BM have been developed for prognostic assessment and prediction of immunotherapy in bladder cancer (BLCA). METHODS: In this study, we used the BLCA public database to explore the relationship between BM-related genes (BMRGs) and prognosis. A novel molecular typing of BLCA was performed using consensus clustering. LASSO regression was used to construct a signature based on BMRGs, and its relationship with prognosis was explored using survival analysis. The pivotal BMRGs were further analyzed to assess its clinical characteristics and immune landscape. Finally, immunohistochemistry was used to detect the expression of the hub gene in BLCA patients who underwent surgery or received immune checkpoint inhibitor (ICI) immunotherapy in our hospital. RESULTS: We comprehensively analyzed the relationship between BMRGs and BLCA, and established a prognostic-related signature which was an independent influence on the prognostic prediction of BLCA. We further screened and validated the pivotal gene-MMP14 in public database. In addition, we found that MMP14 expression in muscle invasive bladder cancer (MIBC) was significantly higher and high MMP14 expression had a poorer response to ICI treatment in our cohort. CONCLUSIONS: Our findings highlighted the satisfactory value of BMRGs and suggested that MMP14 may be a potential biomarker in predicting prognosis and response to immunotherapy in BLCA.

Time-course and muscle-specific gene expression of matrix metalloproteinases and inflammatory cytokines in response to acute treadmill exercise in rats.

BACKGROUND: The extracellular matrix (ECM) of skeletal muscle plays a pivotal role in tissue repair and growth, and its remodeling tightly regulated by matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and inflammatory cytokines. This study aimed to investigate changes in the mRNA expression of MMPs (Mmp-2 and Mmp-14), TIMPs (Timp-1 and Timp-2), and inflammatory cytokines (Il-1ß, Tnf-α, and Tgfß1) in the soleus (SOL) and extensor digitorum longus (EDL) muscles of rats following acute treadmill exercise. Additionally, muscle morphology was examined using hematoxylin and eosin (H&E) staining. METHODS AND RESULTS: Male rats were subjected to acute treadmill exercise at 25 m/min for 60 min with a %0 slope. The mRNA expression of ECM components and muscle morphology in the SOL and EDL were assessed in both sedentary and exercise groups at various time points (immediately (0) and 1, 3, 6, 12, and 24 h post-exercise). Our results revealed a muscle-specific response, with early upregulation of the mRNA expression of Mmp-2, Mmp-14, Timp-1, Timp-2, Il-1ß, and Tnf-α observed in the SOL compared to the EDL. A decrease in Tgfß1 mRNA expression was evident in the SOL at all post-exercise time points. Conversely, Tgfß1 mRNA expression increased at 0 and 3 h post-exercise in the EDL. Histological analysis also revealed earlier cell infiltration in the SOL than in the EDL following acute exercise. CONCLUSIONS: Our results highlight how acute exercise modulates ECM components and muscle structure differently in the SOL and EDL muscles, leading to distinct muscle-specific responses.

Calreticulin regulates the expression of MMP14 and ADAR1 through EIF2AK2 signaling to promote the proliferation and progression of malignant melanoma cells.

It has been demonstrated that calreticulin (CALR) is expressed abnormally in various tumors and is involved in the occurrence and development of tumors. In this study, CALR and EIF2AK2 expression was measured in the clinical specimens of 39 patients with melanoma. Then, we constructed knockdown and overexpression cell models of CALR and EIF2AK2 and used wound healing and Transwell assays to observe cell migration and invasion. Apoptosis, EDU, and ROS assays were used to measure cell apoptosis and proliferation, as well as ROS levels. The effect of CALR on endoplasmic reticulum stress was detected using endoplasmic reticulum fluorescent probes. Western blotting was used to detect protein levels of CALR, EIF2AK2, ADAR1, and MMP14. The results indicated that CALR and EIF2AK2 expression levels were significantly higher in human melanoma tissues than in adjacent non-tumor tissue. In addition, we found a correlation between CALR and the expression of EIF2AK2 and MMP14, and the experimental results indicated that overexpression of CALR significantly upregulated the expression of EIF2AK2, MMP14, and ADAR1, while knockdown of CALR inhibited their expression. Notably, the knockdown of EIF2AK2 in the CALR overexpression group blocked the upregulation of MMP14 and ADAR1 expression by CALR, and the knockdown of both CALR and EIF2AK2 significantly inhibited MMP14 and ADAR1 expression. In conclusion, CALR and EIF2AK2 play a promoting role in melanoma progression, and knockdown of CALR and EIF2AK2 may be an effective anti-tumor target, and its mechanism may be through MMP14, ADAR1 signaling.

MCT4 and CD147 colocalize with MMP14 in invadopodia and support matrix degradation and invasion by breast cancer cells.

Expression levels of the lactate-H+ cotransporter MCT4 (also known as SLC16A3) and its chaperone CD147 (also known as basigin) are upregulated in breast cancers, correlating with decreased patient survival. Here, we test the hypothesis that MCT4 and CD147 favor breast cancer invasion through interdependent effects on extracellular matrix (ECM) degradation. MCT4 and CD147 expression and membrane localization were found to be strongly reciprocally interdependent in MDA-MB-231 breast cancer cells. Overexpression of MCT4 and/or CD147 increased, and their knockdown decreased, migration, invasion and the degradation of fluorescently labeled gelatin. Overexpression of both proteins led to increases in gelatin degradation and appearance of the matrix metalloproteinase (MMP)-generated collagen-I cleavage product reC1M, and these increases were greater than those observed upon overexpression of each protein alone, suggesting a concerted role in ECM degradation. MCT4 and CD147 colocalized with invadopodia markers at the plasma membrane. They also colocalized with MMP14 and the lysosomal marker LAMP1, as well as partially with the autophagosome marker LC3, in F-actin-decorated intracellular vesicles. We conclude that MCT4 and CD147 reciprocally regulate each other and interdependently support migration and invasiveness of MDA-MB-231 breast cancer cells. Mechanistically, this involves MCT4-CD147-dependent stimulation of ECM degradation and specifically of MMP-mediated collagen-I degradation. We suggest that the MCT4-CD147 complex is co-delivered to invadopodia with MMP14.

Intercellular transfer of cancer cell invasiveness via endosome-mediated protease shedding.

Overexpression of the transmembrane matrix metalloproteinase MT1-MMP/MMP14 promotes cancer cell invasion. Here we show that MT1-MMP-positive cancer cells turn MT1-MMP-negative cells invasive by transferring a soluble catalytic ectodomain of MT1-MMP. Surprisingly, this effect depends on the presence of TKS4 and TKS5 in the donor cell, adaptor proteins previously implicated in invadopodia formation. In endosomes of the donor cell, TKS4/5 promote ADAM-mediated cleavage of MT1-MMP by bridging the two proteases, and cleavage is stimulated by the low intraluminal pH of endosomes. The bridging depends on the PX domains of TKS4/5, which coincidently interact with the cytosolic tail of MT1-MMP and endosomal phosphatidylinositol 3-phosphate. MT1-MMP recruits TKS4/5 into multivesicular endosomes for their subsequent co-secretion in extracellular vesicles, together with the enzymatically active ectodomain. The shed ectodomain converts non-invasive recipient cells into an invasive phenotype. Thus, TKS4/5 promote intercellular transfer of cancer cell invasiveness by facilitating ADAM-mediated shedding of MT1-MMP in acidic endosomes.

Clinical significance and immune characteristics analysis of miR-221-3p and its key target genes related to epithelial-mesenchymal transition in breast cancer.

BACKGROUND: MicroRNA-221-3p (miR-221-3p) facilitates the advancement of breast cancer (BC) through the induction of epithelial-mesenchymal transition (EMT). Our research aimed to utilize bioinformatics to discover possible EMT-related target genes (ETGs) of miR-221-3p and examine their roles in breast cancer. METHODS: We employed bioinformatics techniques to identify ten key ETGs of miR-221-3p. Subsequently, we conducted an extensive analysis of both miR-221-3p and the ten ETGs, including clinical significance and immune characteristics. RESULTS: The expression of miR-221-3p was notably higher in Basal-like BC compared to other subtypes and adjacent normal tissue. Our pathway analysis suggested that miR-221-3p might regulate EMT through the MAPK signaling pathway by targeting its ETGs. Among the ETGs, seven core genes (EGFR, IGF1, KDR, FGF2, KIT, FGFR1, and FGF1) exhibited downregulation in BC. Conversely, ERBB2, SDC1, and MMP14 showed upregulation in BC and displayed potential diagnostic value. The analysis of prognostication indicated that increased levels of SDC1 and MMP14 were correlated with an unfavorable prognosis, whereas elevated expression of KIT was associated with a more favorable prognosis. The infiltration of various immune cells and the expression of immune checkpoint genes (ICGs) exhibited positive correlations with most ETGs and miR-221-3p. SDC1 exhibited a greater tumor mutational burden (TMB) score, while ERBB2, KDR, FGF2, KIT, FGFR1, and FGF1 showed lower TMB scores. Furthermore, decreased ERBB2 and KDR expression levels were correlated with elevated microsatellite instability (MSI) scores. Elevated expression of ETGs was linked to decreased mRNA stemness indices (mRNAsi), whereas miR-221-3p displayed the opposite pattern. Most ETGs and miR-221-3p expression exhibited a negative correlation with IC50 values for drugs. Among the ETGs, amplification was the most significant genetic alteration, except for IGF1. CONCLUSION: In conclusion, miR-221-3p acts as a unique indicator for Basal-like BC. The examination revealed ten essential ETGs of miR-221-3p, some of which show potential as diagnostic and prognostic markers. The in-depth examination of these ten ETGs and miR-221-3p indicates their participation in the development of BC, emphasizing their promise as innovative targets for therapy in BC patients.

MMP14high macrophages orchestrate progressive pulmonary fibrosis in SR-Ag-induced hypersensitivity pneumonitis.

Fibrotic hypersensitivity pneumonitis (FHP) is a fatal interstitial pulmonary disease with limited treatment options. Lung macrophages are a heterogeneous cell population that exhibit distinct subsets with divergent functions, playing pivotal roles in the progression of pulmonary fibrosis. However, the specific macrophage subpopulations and underlying mechanisms involved in the disease remain largely unexplored. In this study, a decision tree model showed that matrix metalloproteinase-14 (MMP14) had higher scores for important features in the up-regulated genes in macrophages from mice exposed to the Saccharopolyspora rectivirgula antigen (SR-Ag). Using single-cell RNA sequencing (scRNA-seq) analysis of hypersensitivity pneumonitis (HP) mice profiles, we identified MMP14high macrophage subcluster with a predominant M2 phenotype that exhibited higher activity in promoting fibroblast-to myofibroblast transition (FMT). We demonstrated that suppressing toll-like receptor 2 (TLR2) and nuclear factor kappa-B (NF-κB) could attenuate MMP14 expression and exosome secretion in macrophages stimulation with SR-Ag. The exosomes derived from MMP14-overexpressing macrophages were found to be more effective in regulating the transition of fibroblasts through exosomal MMP14. Importantly, it was observed that the transfer of MMP14-overexpressing macrophages into mice promoted lung inflammation and fibrosis induced by SR-Ag. NSC-405020 binding to the hemopexin domain (PEX) of MMP-14 ameliorated lung inflammation and fibrosis induced by SR-Ag in mice. Thus, MMP14-overexpressing macrophages may be an important mechanism contributing to the exacerbation of allergic reactions. Our results indicated that MMP14 in macrophages has the potential to be a therapeutic target for HP.

CLDN1 silencing suppresses the proliferation and migration of airway smooth muscle cells by modulating MMP14.

Airway remodeling is an important pathologic factor in the progression of asthma. Abnormal proliferation and migration of airway smooth muscle cells (ASMCs) are important pathologic mechanisms in severe asthma. In the current study, claudin-1 (CLDN1) was identified as an asthma-related gene and was upregulated in ASMCs stimulated with platelet-derived growth factor BB (PDGF-BB). Cell counting kit-8 and EdU assays were used to evaluate cell proliferation, and transwell assay was carried out to analyze cell migration and invasion. The levels of inflammatory factors were detected using enzyme-linked immunosorbent assay. The results showed that CLDN1 knockdown inhibited the proliferation, migration, invasion, and inflammation of ASMCs treated with PDGF-BB, whereas overexpression of CLDN1 exhibited the opposite effects. Protein-protein interaction assay and co-immunoprecipitation revealed that CLDN1 directly interacted with matrix metalloproteinase 14 (MMP14). CLDN1 positively regulated MMP14 expression in asthma, and MMP14 overexpression reversed cell proliferation, migration, invasion, and inflammation induced by silenced CLDN1. Taken together, CLDN1 promotes PDGF-BB-induced cell proliferation, migration, invasion, and inflammatory responses of ASMCs by upregulating MMP14 expression, suggesting a potential role for CLDN1 in airway remodeling in asthma.

Mmp14 is required for matrisome homeostasis and circadian rhythm in fibroblasts.

The circadian clock in tendon regulates the daily rhythmic synthesis of collagen-I and the appearance and disappearance of small-diameter collagen fibrils in the extracellular matrix. How the fibrils are assembled and removed is not fully understood. Here, we first showed that the collagenase, membrane type I-matrix metalloproteinase (MT1-MMP, encoded by Mmp14), is regulated by the circadian clock in postnatal mouse tendon. Next, we generated tamoxifen-induced Col1a2-Cre-ERT2::Mmp14 KO mice (Mmp14 conditional knockout (CKO)). The CKO mice developed hind limb dorsiflexion and thickened tendons, which accumulated narrow-diameter collagen fibrils causing ultrastructural disorganization. Mass spectrometry of control tendons identified 1195 proteins of which 212 showed time-dependent abundance. In Mmp14 CKO mice 19 proteins had reversed temporal abundance and 176 proteins lost time dependency. Among these, the collagen crosslinking enzymes lysyl oxidase-like 1 (LOXL1) and lysyl hydroxylase 1 (LH1; encoded by Plod2) were elevated and had lost time-dependent regulation. High-pressure chromatography confirmed elevated levels of hydroxylysine aldehyde (pyridinoline) crosslinking of collagen in CKO tendons. As a result, collagen-I was refractory to extraction. We also showed that CRISPR-Cas9 deletion of Mmp14 from cultured fibroblasts resulted in loss of circadian clock rhythmicity of period 2 (PER2), and recombinant MT1-MMP was highly effective at cleaving soluble collagen-I but less effective at cleaving collagen pre-assembled into fibrils. In conclusion, our study shows that circadian clock-regulated Mmp14 controls the rhythmic synthesis of small diameter collagen fibrils, regulates collagen crosslinking, and its absence disrupts the circadian clock and matrisome in tendon fibroblasts.

Association of MMP3, MMP14, and MMP25 gene polymorphisms with cerebral stroke risk: a case-control study.

BACKGROUND: Cerebral stroke (CS) is the leading cause of death in China, and a complex disease caused by both alterable risk factors and genetic factors. This study intended to investigate the association of MMP3, MMP14, and MMP25 single nucleotide polymorphisms (SNPs) with CS risk in a Chinese Han population. METHODS: A total of 1,348 Han Chinese were recruited in this case-control study. Four candidate loci including rs520540 A/G and rs679620 T/C of MMP3, rs2236302 G/C of MMP14, and rs10431961 T/C of MMP25 were successfully screened. The correlation between the four SNPs and CS risk was assessed by logistic regression analysis. The results were analyzed by false-positive report probability (FPRP) for chance or significance. The interactions between four SNPs associated with CS risk were assessed by multifactor dimensionality reduction (MDR). RESULTS: rs520540 A/G and rs679620 C/T SNP in MMP3 were associated with risk of CS in allele, codominant, dominant and log-additive models. Ischemic stroke risk were significantly lower in carriers with rs520540-A allele and rs679620-T allele than those with G/G or C/C genotypes. However, rs520540-A allele and rs679620-T allele were associated with higher risk of hemorrhagic stroke. Stratified analysis showed that these two SNPs were associated with reduced risk of CS in aged < 55 years, non-smoking and non-drinking participants, and rs679620 SNP also reduced CS risk in male participants. The levels of uric acid, high-density lipoprotein cholesterol, and eosinophil were different among patients with different genotypes of rs520540 and rs679620. No statistically significant association was found between MMP14 rs2236302 G/C or MMP25 rs10431961 T/C with CS even after stratification by stroke subtypes, age, gender as well as smoking and drinking conditions in all the genetic models. CONCLUSION: MMP3 rs520540 A/G and rs679620 C/T polymorphisms were associated with CS risk in the Chinese Han population, which provides useful information for the prevention and diagnosis of CS.

Assessment of MMP14, CAV2, CLU and SPARCL1 expression profiles in endometriosis.

Endometriotic cells exhibit a notable degree of invasiveness and some characteristics of tissue remodeling underlying lesion formation. In this regard, do matrix metalloproteinases 14 (MMP14) and other related genes such as SPARC-like protein 1 (SPARCL1), caveolin 2 (CAV2), and clusterin (CLU) exert any significant influence in the processes of endometriosis development and pathophysiology is not apparent. We aim to assess whether these genes could serve as potential diagnostic biomarkers in endometriosis. Microarray-based gene expression analysis was performed on total RNA extracted from endometriotic tissue samples treated with and without gonadotropin-releasing hormone agonist (GnRHa). The GnRHa untreated patients were considered the control group. The validation of genes was performed using quantitative real-time polymerase chain reaction (qRT-PCR). qRT-PCR analysis showed significant downregulation in the expression of MMP14 (p = 0.024), CAV2 (p = 0.017), and upregulation of CLU (p = 0.005) in endometriosis patients treated with GnRHa. SPARCL1 did not show any significant (p = 0.30) change in the expression compared to the control group. These data have the potential to contribute to the comprehension of the molecular pathways implicated in the remodeling of the extracellular matrix, which is a vital step for the physiology of the endometrium. Based on the result, it is concluded that changes in the expression of MMP14, CAV2, and CLU post-treatment imply their role in the pathophysiology of endometriosis and may serve as a potential diagnostic biomarker of endometriosis in response to GnRHa treatment in patients with ovarian endometrioma.

KIF16B drives MT1-MMP recycling in macrophages and promotes co-invasion of cancer cells.

The matrix metalloproteinase MT1-MMP is a central effector of cellular proteolysis. Accordingly, regulation of the surface-localized pool of MT1-MMP is crucial for cell migration and invasion. Here, we identify the superprocessive kinesin KIF16B as a major driver of fast recycling of MT1-MMP to the surface of primary human macrophages. KIF16B associates with MT1-MMP on Rab14-positive vesicles, and its depletion results in strongly reduced MT1-MMP surface levels, as shown by microscopical, biochemical, and cell-sorting approaches. As a consequence, KIF16B-depleted macrophages exhibit strongly reduced matrix degradation and invasion. We further identify the cargo-binding C-terminus of KIF16B as a critical element of MT1-MMP transport, as its overexpression uncouples MT1-MMP vesicles from the endogenous motor, thus leading to a reduction of surface-associated MT1-MMP and to reduced matrix degradation and invasion. Importantly, depletion of KIF16B in primary macrophages also reduces the co-invasion of cancer cells from tumor spheroids, pointing to the KIF16B-driven recycling pathway in macrophages as an important regulatory element of the tumor microenvironment.

Global, but not chondrocyte-specific, MT1-MMP deficiency in adult mice causes inflammatory arthritis.

Membrane-type I metalloproteinase (MT1-MMP/MMP14) plays a key role in various pathophysiological processes, indicating an unaddressed need for a targeted therapeutic approach. However, mice genetically deficient in Mmp14 show severe defects in development and growth. To investigate the possibility of MT1-MMP inhibition as a safe treatment in adults, we generated global Mmp14 tamoxifen-induced conditional knockout (Mmp14kd) mice and found that MT1-MMP deficiency in adult mice resulted in severe inflammatory arthritis. Mmp14kd mice started to show noticeably swollen joints two weeks after tamoxifen administration, which progressed rapidly. Mmp14kd mice reached a humane endpoint 6 to 8 weeks after tamoxifen administration due to severe arthritis. Plasma TNF-α levels were also significantly increased in Mmp14kd mice. Detailed analysis revealed chondrocyte hypertrophy, synovial fibrosis, and subchondral bone remodeling in the joints of Mmp14kd mice. However, global conditional knockout of MT1-MMP in adult mice did not affect body weight, blood glucose, or plasma cholesterol and triglyceride levels. Furthermore, we observed substantial expression of MT1-MMP in the articular cartilage of patients with osteoarthritis. We then developed chondrocyte-specific Mmp14 tamoxifen-induced conditional knockout (Mmp14chkd) mice. Chondrocyte MT1-MMP deficiency in adult mice also caused apparent chondrocyte hypertrophy. However, Mmp14chkd mice did not exhibit synovial hyperplasia or noticeable arthritis, suggesting that chondrocyte MT1-MMP is not solely responsible for the onset of severe arthritis observed in Mmp14kd mice. Our findings also suggest that highly cell-type specific inhibition of MT1-MMP is required for its potential therapeutic use.

The selective regulation of immune responses by matrix metalloproteinase MMP14 in Ostrinia furnacalis.

Matrix metalloproteinases (MMPs) are crucial for tissue remodeling and immune responses in insects, yet it remains unclear how MMPs affect the various immune processes against pathogenic infections and whether the responses vary among insects. In this study, we used the lepidopteran pest Ostrinia furnacalis larvae to address these questions by examining the changes of immune-related gene expression and antimicrobial activity after the knockdown of MMP14 and bacterial infections. We identified MMP14 in O. furnacalis using the rapid amplification of complementary DNA ends (RACE), and found that it was conserved and belonged to the MMP1 subfamily. Our functional investigations revealed that MMP14 is an infection-responsive gene, and its knockdown reduces phenoloxidase (PO) activity and Cecropin expression, while the expressions of Lysozyme, Attacin, Gloverin, and Moricin are enhanced after MMP14 knockdown. Further PO and lysozyme activity determinations showed consistent results with gene expression of these immune-related genes. Finally, the knockdown of MMP14 decreased larvae survival to bacterial infections. Taken together, our data indicate that MMP14 selectively regulates the immune responses, and is required to defend against bacterial infections in O. furnacalis larvae. Conserved MMPs may serve as a potential target for pest control using a combination of double-stranded RNA and bacterial infection.

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.

Gallbladder cancer-associated genetic variants rs1003349 and rs1004030 regulate MMP14 expression by altering SOX10- and MYB-binding sites.

The pathogenesis of gallbladder cancer is complex, involving environmental and genetic risk factors. The matrix metallopeptidase 14 (MMP14) alters the tumor microenvironment and promotes tumorigenesis. In this study, we have characterized the role of the MMP14 promoter variants rs1004030 and rs1003049 in gallbladder cancer pathogenesis. Previously, we have shown the association of rs1004030 and rs1003049 with GBC and allele-specific differential expression of MMP14 in GBC patients. These variants reside within the cis-regulatory element (CRE) with high DNase and H3K4me3 signals, suggesting an active regulatory role in MMP14 expression. The luciferase-based reporter assay showed the role of promoter variants on expression levels in two GBC cell lines. Deleting the 119 bp promoter region surrounding the variants rs1004030 and rs1003049 by CRISPR-Cas9 genome editing resulted in reduced MMP14 expression in G415 cells. Electrophoretic mobility shift assay shows the presence of risk allele 'C'/'G' at rs1004030 and rs1003049 and create binding sites for transcription factors SOX10 and MYB, respectively. Further, stable knockdown of these transcription factors in G415 and TGBC1TKB cells showed reduced expression of MMP14. However, in both GBC cells, ectopic expression of these transcription factors increased the expression of MMP14. Rescue of MYB and SOX10 expression levels showed a significant increase in luciferase activity only in risk allele-carrying constructs. In conclusion, our study unveils a mechanistic role of the MMP14 promoter variants rs1004030 and rs1003049 in gallbladder cancer.

Critical role of transcriptome-wide m6A methylation in the aqueous humor of patients with pseudoexfoliation glaucoma.

N6-methyladenosine (m6A) modification is one of the most common types of methylation modifications in eukaryotic mRNA. However, its role in the pathogenesis of pseudoexfoliation glaucoma (PXG) has not yet been reported. To enhance understanding in this regard, we assessed the m6A methylome in the aqueous humor of patients with PXG. MeRIP-Seq and RNA-Seq analyses were performed to compare the m6A methylomes and gene expression profiles of the aqueous humor of patients with PXG with those of patients with age-related cataract (ARC). Colorimetric m6A quantification was performed to detect global m6A levels. Quantitative reverse transcription PCR confirmed the expression of m6A-related enzymes and mRNAs in both groups. Results showed significantly higher aqueous humor m6A levels in the PXG group than in the ARC group. Five m6A-related enzymes, including METTL3, YTHDC2, HNRNPA2B1, HNRNPC, and LRPPRC, were significantly up-regulated in PXG specimens. We also observed 9728 m6A-modified peaks related to 6126 gene transcripts in the PXG group, with more than 250 genes containing one m6A peak (hypomethylated or hypermethylated). The distribution of the m6A peaks was enriched in coding sequences and 3'-untranslated regions for both groups. GGAC motif structures were also significantly enriched. Bioinformatics analysis further revealed that m6A plays a critical role in extracellular matrix formation and histone deacetylation. Additionally, MMP14, ADAMTSL1, FN1, and HDAC1 showed significant changes in m6A methylation and mRNA expression in the PXG group. Therefore, m6A methylation may regulate extracellular matrix composition in PXG and METTL3 may be a pivotal regulator of this process. In the future, it would be necessary to investigate MMP14, ADAMTSL1, FN1, and HDAC1, which are potential target genes.