MT1-MMP and RECK: opposite and essential roles in hematopoietic stem and progenitor cell retention and migration

Low RECK Expression Is Part of the Cervical Carcinogenesis Mechanisms

Human papillomavirus (HPV)-induced carcinogenesis comprises alterations in the expression and activity of matrix metalloproteinases (MMP) and their regulators. Reversion-inducing Cysteine-rich protein with Kazal motifs (RECK) inhibits the activation of specific metalloproteinases and its expression is frequently lost in human cancers. Here we analyzed the role of RECK in cervical carcinogenesis. Cervical cancer derived cell lines over expressing RECK were used to determine tumor kinetics as well as, cellular, immune and molecular properties in vivo. Besides, we analyzed RECK expression in cervical cancer samples. RECK over expression (RECK+) delayed tumor growth and increased overall survival in vivo. RECK+ tumors displayed an increase in lymphoid-like inflammatory infiltrating cells, reduced number and viability of tumor and endothelial cells and lower collagenase activity. RECK+ tumors exhibited an enrichment of cell adhesion processes both in the mouse model and cervical cancer clinical samples. Finally, we found that lower RECK mRNA levels were associated with cervical lesions progression and worse response to chemotherapy in cervical cancer patients. Altogether, we show that increased RECK expression reduced the tumorigenic potential of HPV-transformed cells both in vitro and in vivo, and that RECK down regulation is a consistent and clinically relevant event in the natural history of cervical cancer.

Delay in primordial germ cell migration in adamts9 knockout zebrafish

Adamts9 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 9) is one of a few metalloproteinases structurally conserved from C. elegans to humans and is indispensable in germ cell migration in invertebrates. However, adamts9's roles in germ cell migration in vertebrates has not been examined. In the present study, we found zygotic expression of adamts9 started around the germ ring stage and reached peak levels at 3 days post fertilization (dpf) in zebrafish. The migration of primordial germ cells (PGC) was completed within 24 hours (h) in wildtype siblings, while a delay in PGC migration was found at 15 and 24-h post-fertilization (hpf) in the Adamts9 knockout (KO). However, the delayed PGC migration in Adamts9 KO disappeared at 48 hpf. Our study suggests a conserved function of Adamts9 in germ cell migration among invertebrates and vertebrates. In addition, our results also suggest that Adamts9 is not essential for germ cell migration as reported in C. elegans, possibly due to expansion of Adamts family members and compensatory roles from other metalloproteinases in vertebrates. Further studies are required in order to elucidate the functions and mechanisms of metalloproteinases in germ cell migration and gonad formation in vertebrates.

Expression and Activity of Matrix Metalloproteinases in Leukemia

Matrix metalloproteinases (MMPs) are responsible for the degradation of extracellular matrix components and hence play a crucial role in physiological and pathologic processes. The imbalance between the expression of MMPs and their inhibitors can be effective in leukemic cell processes such as migration, angiogenesis, survival, and apoptosis, playing a key role in the progression and prognosis of leukemia. In this review, we discuss the potential involvement of MMPs and their inhibitors in the pathogenesis and progression of leukemia by examining their role in the prognosis of leukemia. Inducing leukemic cell growth, migration, invasiveness, and angiogenesis are the main roles of MMPs in leukemia progression mediated by their degradative activity. Given the important role of MMPs in leukemia progression, further clinical trials are needed to confirm the link between MMPs' expressions and leukemia prognosis. It is hoped to use MMPs as therapeutic targets to improve patients' health by recognizing the prognostic value of MMPs in leukemia and their effect on the progression of these malignancies and their response to treatment.

Assessment of Proteolytic Activities in the Bone Marrow Microenvironment

During cytokine- or chemotherapy-induced hematopoietic stem cell (HSC) mobilization, a highly proteolytic microenvironment can be observed in the bone marrow that has a strong influence on adhesive and chemotactic interactions of HSC with their niches. The increase of proteases during mobilization goes along with a decrease of endogenous protease inhibitors. Prominent members of the proteases involved in HSC mobilization belong to the families of matrix metalloproteinases and cathepsins, which are able to degrade chemokines/cytokines, extracellular matrix components, and membrane-bound adhesion receptors. To determine the functional activity of different proteolytic enzymes, zymographic analyses with different substrates and pH conditions can be employed. An involvement of cysteine cathepsins can be determined by the "active site labeling" technique using a modified inhibitor irreversibly binding to the active center of the enzymes. Intact or degraded chemokines and cytokines, which fall into the range between 1000 and 20,000 Da, can readily be detected by MALDI-TOF analysis. These three methods can help to detect proteolytic activities directly involved in the mobilization process.

Effects of treadmill exercise on cerebral angiogenesis and MT1-MMP expression after cerebral ischemia in rats

INTRODUCTION

Despite the increased understanding of treadmill training on angiogenesis of stroke patients, its mechanism is not clearly known. The metalloproteinase membrane type 1-metalloprotease (MT1-MMP) promotes the regeneration of the peripheral vessels but seldom research on the regeneration of cerebral blood vessels. This study was designed to investigate the effects of treadmill exercise on angiogenesis and MT1-MMP expression after cerebral ischemia in rats.

METHODS

The adult male Sprague Dawley(SD) rats were randomly divided into three groups: sham operation group, the middle cerebral artery occlusion group(MCAO) and middle cerebral artery occlusion group(MCAO)+exercise group. In 4d, 7d or 14d after MCAO, respectively, the rats' neurological function was evaluated by the modified neurologic severity scores (mNSS); the microvessel numbers in areas surrounding cerebral ischemia were counted with Microvessel Density(MVD)analysis; the levels of MT1-MMP and reversion-inducing cysteine-rich protein with Kazalmotifs (RECK) were detected by Western-blot and immunohistochemical method.

RESULTS

Compared with MCAO group, the number of capillaries and the level of MT1-MMP expression around the area of cerebral ischemia were significantly increased in each exercise group (p < 0.05), while the level of RECK expression and the scores of mNSS in each exercise group were significantly decreased (p < 0.05).

CONCLUSION

This study suggested that treadmill exercise training can significantly promote angiogenesis and improve neurological function after cerebral ischemia. Its mechanism may be related to the upgraduation of the MT1-MMP expression in brain microvessels surrounding area of the ischemic rat.

Hypoxia Activates Src and Promotes Endocytosis Which Decreases MMP-2 Activity and Aggravates Renal Interstitial Fibrosis

The aggravation of renal interstitial fibrosis in the advanced-stage of chronic kidney disease is related to decreased matrix metalloproteinase-2 (MMP-2) activity, which is induced by hypoxia in the kidney; however, the specific mechanism remains unclear. We previously demonstrated that inhibition of Caveolin-1, a key gene involved in endocytosis, increased MMP-2 activity in hypoxic HK-2 cells. It has been reported that activated Src (phospho-Src Tyr416) is a key molecule in multiple fibrotic pathways. However, whether Src functions on the regulation of Caveolin-1 and MMP-2 activity in hypoxic HK-2 cells remains poorly understood. To explore the underlying mechanism, a rat model of renal interstitial fibrosis was established, then we observed obvious hypoxia in fibrotic kidney tissue and the protein levels of phospho-Src and Caveolin-1 increased, while MMP-2 activity decreased. Next, we treated HK-2 cells with the phospho-Src inhibitor PP1. Compared with normal cells grown in hypoxia, in cells treated with PP1, the protein levels of phospho-Src and Caveolin-1 decreased, as did the protein levels of the MMP-2-activity-regulated molecules RECK (reversion-inducing-cysteine-rich protein with kazal motifs) and TIMP-2 (tissue inhibitor of metalloproteinase-2), while the protein level of MT1-MMP (membrane type 1-matrix metalloproteinase) increased and MMP-2 activity was enhanced. Therefore, hypoxia promotes the phosphorylation of Src and phospho-Src can enhance the endocytosis of HK-2 cells, which leads to decreased MMP-2 activity and aggravates renal interstitial fibrosis.

Current Understanding of the Pathways Involved in Adult Stem and Progenitor Cell Migration for Tissue Homeostasis and Repair

With the advancements in the field of adult stem and progenitor cells grows the recognition that the motility of primitive cells is a pivotal aspect of their functionality. There is accumulating evidence that the recruitment of tissue-resident and circulating cells is critical for organ homeostasis and effective injury responses, whereas the pathobiology of degenerative diseases, neoplasm and aging, might be rooted in the altered ability of immature cells to migrate. Furthermore, understanding the biological machinery determining the translocation patterns of tissue progenitors is of great relevance for the emerging methodologies for cell-based therapies and regenerative medicine. The present article provides an overview of studies addressing the physiological significance and diverse modes of stem and progenitor cell trafficking in adult mammalian organs, discusses the major microenvironmental cues regulating cell migration, and describes the implementation of live imaging approaches for the exploration of stem cell movement in tissues and the factors dictating the motility of endogenous and transplanted cells with regenerative potential.

Regulation of long-term repopulating hematopoietic stem cells by EPCR/PAR1 signaling

The common developmental origin of endothelial and hematopoietic cells is manifested by coexpression of several cell surface receptors. Adult murine bone marrow (BM) long-term repopulating hematopoietic stem cells (LT-HSCs), endowed with the highest repopulation and self-renewal potential, express endothelial protein C receptor (EPCR), which is used as a marker to isolate them. EPCR/protease-activated receptor-1 (PAR1) signaling in endothelial cells has anticoagulant and anti-inflammatory roles, while thrombin/PAR1 signaling induces coagulation and inflammation. Recent studies define two new PAR1-mediated signaling cascades that regulate EPCR(+) LT-HSC BM retention and egress. EPCR/PAR1 signaling facilitates LT-HSC BM repopulation, retention, survival, and chemotherapy resistance by restricting nitric oxide (NO) production, maintaining NO(low) LT-HSC BM retention with increased VLA4 expression, affinity, and adhesion. Conversely, acute stress and clinical mobilization upregulate thrombin generation and activate different PAR1 signaling that overcomes BM EPCR(+) LT-HSC retention, inducing their recruitment to the bloodstream. Thrombin/PAR1 signaling induces NO generation, TACE-mediated EPCR shedding, and upregulation of CXCR4 and PAR1, leading to CXCL12-mediated stem and progenitor cell mobilization. This review discusses new roles for factors traditionally viewed as coagulation related, which independently act in the BM to regulate PAR1 signaling in bone- and blood-forming progenitor cells, navigating their fate by controlling NO production.

Matrix metalloproteinase 14 modulates signal transduction and angiogenesis in the cornea

The cornea is transparent and avascular, and retention of these characteristics is critical to maintaining vision clarity. Under normal conditions, wound healing in response to corneal injury occurs without the formation of new blood vessels; however, neovascularization may be induced during corneal wound healing when the balance between proangiogenic and antiangiogenic mediators is disrupted to favor angiogenesis. Matrix metalloproteinases (MMPs), which are key factors in extracellular matrix remodeling and angiogenesis, contribute to the maintenance of this balance, and in pathologic instances, can contribute to its disruption. Here, we elaborate on the facilitative role of MMPs, specifically MMP-14, in corneal neovascularization. MMP-14 is a transmembrane MMP that is critically involved in extracellular matrix proteolysis, exosome transport, and cellular migration and invasion, processes that are critical for angiogenesis. To aid in developing efficacious therapies that promote healing without neovascularization, it is important to understand and further investigate the complex pathways related to MMP-14 signaling, which can also involve vascular endothelial growth factor, basic fibroblast growth factor, Wnt/β-catenin, transforming growth factor, platelet-derived growth factor, hepatocyte growth factor or chemokines, epidermal growth factor, prostaglandin E2, thrombin, integrins, Notch, Toll-like receptors, PI3k/Akt, Src, RhoA/RhoA kinase, and extracellular signal-related kinase. The involvement and potential contribution of these signaling molecules or proteins in neovascularization are the focus of the present review.

miR-374b-5p suppresses RECK expression and promotes gastric cancer cell invasion and metastasis

AIM: To profile expression of microRNAs (miRNAs) in gastric cancer cells and investigate the effect of miR-374b-5p on gastric cancer cell invasion and metastasis.

METHODS: An miRNA microarray assay was performed to identify miRNAs differentially expressed in gastric cancer cell lines (MGC-803 and SGC-7901) compared with a normal gastric epithelial cell line. Upregulation of miR-374b-5p was newly identified and confirmed via quantitative real-time reverse transcription-PCR (qRT-PCR). MGC-803 cells were transfected with a synthesized anti-miR-374b-5p sequence or a control vector using Lipofectamine reagent, or treated with transfection reagent alone or phosphate-buffered saline as controls. Rate of transfection was verified after 48 h by qRT-PCR. Cells were then subjected to transwell migration, wound scratch and cell counting kit-8 assays. A bioinformatic analysis to identify miR-374b-5p target genes was performed using miRanda, PicTar and TargetScan software. A dual luciferase reporter assay was performed to evaluate the influence of miR-374b-5p on target gene activation, and qRT-PCR and Western blot were used to evaluate the levels of target mRNA and protein following transfection with miR-374b-5p antisense oligonucleotides.

RESULTS: The microarray profiling revealed downregulation of 14 (fold change < 0.667; P < 0.05) and upregulation of 12 (fold change > 1.50; P < 0.05) miRNAs in MGC-803 and SGC-7901 cells compared with GES-1 controls. The upregulation of miR-374b-5p (fold change = 1.75 and 1.64 in MGC-803 and SGC-7901, respectively; P < 0.05) was confirmed by qRT-PCR. Compared with the control groups, the restoration of miR-374b-5p expression with anti-miR-374b-5p significantly suppressed the metastasis, invasion and proliferation of MGC-803 cells. The bioinformatic analysis predicted that the 3’ untranslated region (UTR) of reversion-inducing cysteine-rich protein with Kazal motif (RECK) contains three miR-374b-5p target sequences. RECK was verified as a target gene in a dual luciferase reporter assay showing that activation of RECK 3’UTR-pmirGLO was increased by co-transfection with miR-374b-5p. Finally, transfection of miR-374b-5p antisense oligonucleotides increased mRNA and protein levels of RECK in MGC-803 cells (P < 0.05).

CONCLUSION: These findings indicate that upregulation of miR-374b-5p contributes to gastric cancer cell metastasis and invasion through inhibition of RECK expression.

The role of the nervous system in hematopoietic stem cell mobilization

Hematopoietic stem cells (HSCs) and blood cell progenitors, such as maturing leucocytes, steadily enter from bone marrow (BM) into the circulation under steady-state conditions, and their mobilization is dramatically amplified during stress conditions and by mediators such as granulocyte colony-stimulating factor (G-CSF). This mobilization is dependent upon bone remodeling, the proteolytic enzymes of bone marrow-derived stromal cells, and adhesion molecules such as integrin, but the main mechanisms controlling this traffic are still unclear. The nervous system, as the most important regulator of the body, can affect the mobilization network by secreting catecholamines, so that denervation of catecholaminergic fibers in the BM of mice could lead to declining mobilization in steady state and stress situations, even in the presence of other intact environmental factors in the BM. Thus, due to the importance of the nervous system, we have attempted to give a general overview of how the nervous system is involved in the mobilization of HSCs in this review. Then, we will try to describe the mobilization process induced by the nervous system, which consists of 3 mechanisms: stromal cell-derived factor 1 (SDF-1)/CXC chemokine receptor type 4 (CXCR4), proteolytic enzymes, and bone remodeling.

Evidence for a role of matrix metalloproteinases and their inhibitors in primordial germ cell migration

Understanding the mechanisms that enable migrating cells to reach their targets is of vital importance, as several pathologies, including cardiac defects and some tumours, are consequences of altered cell migration. With a view to evaluating if matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play a role in the active migration of primordial germ cells (PGCs) from their place of origin in extra-embryonic sites towards their final destination in the developing gonads, we analysed the expression of mRNAs encoding nine MMPs and four TIMPs in migrating (E10.5) and post-migrating (E12.5) PGCs by means of quantitative polymerase chain reaction and the presence of MT1-MMP in the membrane of these cells. Our results show that PGCs express MMP-2, MMP-9, MMP-11, MT1-MMP, TIMP-1, TIMP-2 and TIMP-3 at both migrating and non-migrating stages. Comparing expression levels of MMP genes between E10.5 and E12.5 PGCs revealed higher expression in migrating PGCs of MT1- MMP (10.3-fold), MMP-2 (4.8-fold), MMP-11 (3.2-fold) and MMP-9 (2.1-fold). Similarly, the levels of TIMP gene expression were always higher in E12.5 genital ridge somatic cells: TIMP-3 (3.4-fold), TIMP-1 (2.4-fold) and TIMP-2 (1.8-fold). Moreover, the analysis at protein level showed the presence of MT1-MMP in the membrane of migrating PGCs whereas the expression of these metalloproteinase is not detected once the PGCs have reach the urogenital ridges and stop migrating. These results suggest that the change from the motile to non-motile phenotype that occurs during PGC maturation to gonocytes may be mediated in part by enhanced expression of MMPs in migrating PGCs together with higher expression of TIMPs in E12.5 genital ridges.

Hematopoietic Stem Cell Mobilization and Homing after Transplantation: The Role of MMP-2, MMP-9, and MT1-MMP

Hematopoietic stem/progenitor cells (HSPCs) are used in clinical transplantation to restore hematopoietic function. Here we review the role of the soluble matrix metalloproteinases MMP-2 and MMP-9, and membrane type (MT)1-MMP in modulating processes critical to successful transplantation of HSPC, such as mobilization and homing. Growth factors and cytokines which are employed as mobilizing agents upregulate MMP-2 and MMP-9. Recently we demonstrated that MT1-MMP enhances HSPC migration across reconstituted basement membrane, activates proMMP-2, and contributes to a highly proteolytic bone marrow microenvironment that facilitates egress of HSPC. On the other hand, we reported that molecules secreted during HSPC mobilization and collection, such as hyaluronic acid and thrombin, increase MT1-MMP expression in cord blood HSPC and enhance (prime) their homing-related responses. We suggest that modulation of MMP-2, MMP-9, and MT1-MMP expression has potential for development of new therapies for more efficient mobilization, homing, and engraftment of HSPC, which could lead to improved transplantation outcomes.