A novel mechanism of matrix metalloproteinase-9 gene expression implies a role for keratinization

Bilateral Increase of the Matrix Metalloproteinase-9 Expression in Tears After the Unilateral Decrease of Corneal Sensitivity

PURPOSE

The purpose of this study is to analyze bilateral changes of matrix metalloproteinase-9 (MMP-9) expression in the tear film in patients with unilateral neurotrophic keratitis.

METHODS

We included 24 eyes from 24 subjects with normal corneal sensitivity according to Cochet-Bonnet corneal esthesiometry in the control group and 25 subjects with the unilateral neurotrophic keratitis in the unilateral decrease of corneal sensitivity (UDCS) group. The expression of MMP-9 in tears was assessed using point-of-care immunoassay. The clinical parameters including meibomian gland plugging, quality of the secreted meibum, tear secretion using Schirmer I without anesthesia, and corneal erosions were evaluated among the control, affected, and contralateral unaffected eyes in the UDCS group.

RESULTS

Tear MMP-9 grades in affected (2.5 ± 1.0) and contralateral eyes (2.6 ± 0.9) in the UDCS group were higher than those in control eyes (1.5 ± 0.7, P = 0.0003 and P = 0.0006, respectively). The lacrimal secretion decreased in the affected eyes but preserved in the contralateral eyes. There was no difference in corneal erosion scores between control eyes and contralateral eyes in the UDCS group. Tear MMP-9 grades in the contralateral eyes were significantly correlated with the meibum quality grades in the contralateral eyes (r = 0.525 and P = 0.025).

CONCLUSIONS

Patients with the unilateral neurotrophic keratitis demonstrated a significant bilateral increase of the MMP-9 expression in the tear film as compared with controls. Despite the tearing reflex and corneal surface barrier being preserved in the unaffected contralateral eyes, it is necessary to pay attention to the possible attenuation of meibomian gland function in the opposite eyes as well.

Polyphenols from grape pomace induce osteogenic differentiation in mesenchymal stem cells

Polyphenols are increasingly investigated for the treatment of periodontitis and research on their use in dental biomaterials is currently being conducted. Grape pomace extracts are a rich source of polyphenols. In the present study, the polyphenols of two different types of grape pomace were characterized and identified by high-performance liquid chromatography-diode array detector, and the effect of polyphenol-rich grape pomace extracts on mesenchymal stem cell (MSC) osteogenic differentiation was investigated. Solid-liquid extraction was used to recover polyphenols from red and white grape pomace. The two extracts have been characterized through the phenolic content and antioxidant power. Human MSCs (hMSCs) from the bone marrow were cultured both with and without given amounts (10 or 20 µg/ml) of the obtained pomace extracts. Their effects on cell differentiation were evaluated by reverse transcription-quantitative polymerase chain reaction, compared with relevant controls. Results showed that both pomace extracts, albeit different in phenolic composition and concentration, induced multiple effects on hMSC gene expression, such as a decreased receptor activator of nuclear factor κ-B ligand/osteoprotegerin ratio and an enhanced expression of genes involved in osteoblast differentiation, thus suggesting a shift of hMSCs towards osteoblast differentiation. The obtained results provided data in favor of the exploitation of polyphenol properties from grape pomace extracts as complementary active molecules for dental materials and devices for bone regeneration in periodontal defects.

All-Trans Retinoic Acid Enhances Matrix Metalloproteinase 2 Expression and Secretion in Human Myeloid Leukemia THP-1 Cells

All-trans retinoic acid (ATRA) is an effective drug for the induction therapy of acute promyelocytic leukemia. However, the treatment is associated with adverse events such as retinoic acid syndrome (RAS) in some patients, whose histologic characteristics included organ infiltration by leukemic cells. Matrix metalloproteinase 2 (MMP-2) is often upregulated in tumor cells and plays a role in tumor cell migration and invasion by degrading the extracellular matrix. In this study, we examined the possible modulatory effects of ATRA on MMP-2 expression and secretion in human myeloid leukemia cell line THP-1. The cells were treated with various concentrations of ATRA, and MMP-2 expression and secretion were examined. MMP-2 expression and secretion started to increase with ATRA concentration as low as 0.1 nM and gradually increased thereafter. Agonists of retinoic acid receptor (RAR) or retinoid X receptor (RXR) alone could enhance MMP-2 secretion, and RAR or RXR antagonists alone could reverse ATRA-induced MMP-2 secretion. ATRA increased intracellular calcium ion levels, and a calcium-channel blocker inhibited ATRA-induced MMP-2 secretion. Dexamethasone suppressed ATRA-induced MMP-2 secretion. Our results suggest that ATRA enhances MMP-2 expression and secretion in human myeloid leukemia THP-1 cells in a calcium ion dependent manner through RAR/RXR signaling pathways, and this enhanced expression and secretion may be associated with the possible mechanisms of RAS.

MMP-2, -9 and TIMP-1, -2 assays in keratinocyte cultures

To determine the status of tissue metabolism in the epidermis, matrix metalloproteinase (MMP)-2 and -9 and tissue inhibitor of metalloproteinases (TIMP)-1 and -2 can be detected using keratinocytes in culture. In addition to Western blotting analysis, gelatin zymography for MMP-2 and -9 and the reverse zymography for TIMP-1 and -2 are useful methods for evaluating such protein expressions both qualitatively and quantitatively, because MMP-2 and MMP-9 are known as gelatinase. Moreover, real-time analysis for zymography can be performed using fluorescein isothiocyanate-labelled gelatin.

Matrix metalloproteinase 9 is a distal-less 3 target-gene in placental trophoblast cells

Matrix metalloproteinases (MMPs) are enzymes that regulate extracellular matrix composition and contribute to cell migration. Microarray studies in mouse placenta suggested that MMP-9 transcript abundance was dependent on distal-less 3 (Dlx3), a placental-specific transcriptional regulator; however, it was not clear if this was a direct or indirect effect. Here we investigate mechanism(s) for Dlx3-dependent MMP-9 gene transcription and gelatinase activity in placental trophoblasts. Initial studies confirmed that MMP-9 activity was reduced in placental explants from Dlx3(-/-) mice and that murine MMP-9 promoter activity was induced by Dlx3 overexpression. Two binding sites within a murine MMP-9 promoter fragment bound Dlx3, and mutations in both elements reduced basal MMP-9-luciferase reporter activity and abolished regulation by Dlx3. Chromatin immunoprecipitation studies in JEG3 cells confirmed Dlx3 binding to the endogenous human MMP-9 promoter at three distinct sites and knockdown of human Dlx3 resulted in reduced endogenous MMP-9 transcripts and secreted activity. These studies provide novel evidence that Dlx3 is involved directly in the transcriptional regulation of mouse and human MMP-9 gene expression in placental trophoblasts.

Keratinization-associated miR-7 and miR-21 regulate tumor suppressor reversion-inducing cysteine-rich protein with kazal motifs (RECK) in oral cancer

MicroRNAs (miRNAs) are small non-coding RNAs that posttranscriptionally regulate gene expression during many biological processes. Recently, the aberrant expressions of miRNAs have become a major focus in cancer research. The purpose of this study was to identify deregulated miRNAs in oral cancer and further focus on specific miRNAs that were related to patient survival. Here, we report that miRNA expression profiling provided more precise information when oral squamous cell carcinomas were subcategorized on the basis of clinicopathological parameters (tumor primary site, histological subtype, tumor stage, and HPV16 status). An innovative radar chart analysis method was developed to depict subcategories of cancers taking into consideration the expression patterns of multiple miRNAs combined with the clinicopathological parameters. Keratinization of tumors and the high expression of miR-21 were the major factors related to the poor prognosis of patients. Interestingly, a majority of the keratinized tumors expressed high levels of miR-21. Further investigations demonstrated the regulation of the tumor suppressor gene reversion-inducing cysteine-rich protein with kazal motifs (RECK) by two keratinization-associated miRNAs, miR-7 and miR-21. Transfection of miR-7 and miR-21-mimics reduced the expression of RECK through direct miRNA-mediated regulation, and these miRNAs were inversely correlated with RECK in CAL 27 orthotopic xenograft tumors. Furthermore, a similar inverse correlation was demonstrated in CAL 27 cells treated in vitro by different external stimuli such as trypsinization, cell density, and serum concentration. Taken together, our data show that keratinization is associated with poor prognosis of oral cancer patients and keratinization-associated miRNAs mediate deregulation of RECK which may contribute to the aggressiveness of tumors.

Interaction of clusterin and matrix metalloproteinase-9 and its implication for epithelial homeostasis and inflammation

Uncontrolled increases of matrix metalloproteinase-9 (MMP-9) activity have been causally linked to epithelial barrier disruption and severe symptoms of inflammatory diseases such as dry eye (DE). The data presented here show that the anti-inflammatory, cytoprotective intracellular and extracellular chaperone protein clusterin (CLU) interacts with MMP-9 both inside and outside epithelial cells. CLU bound very strongly to active MMP-9, with an affinity constant K(D) of 2.63 nmol/L. Unexpectedly, CLU had a much higher affinity for pro-MMP-9 than for active MMP-9 or pro-MMP-2, requiring the N-terminal propeptide domain of pro-MMP-9. The significance of the interaction between CLU and MMP-9 was demonstrated by the observation that CLU prevents stress-induced MMP-9 aggregation and inhibits MMP-9 enzymatic activity. Furthermore, CLU inhibited MMP-9-mediated disintegration of the tight junction structure formed between human epithelial cells. Additionally, CLU inhibited enzymatic activities of MMP-2, MMP-3, and MMP-7. Treatment with proinflammatory cytokines, which are known to increase MMP-9 transcription under inflammatory conditions, reduced the expression of CLU in human epithelial cells. Similarly, in a mouse model of human DE, inflammatory stress depleted CLU in the ocular surface epithelium but allowed MMP-9 to prevail therein. The present results thus provide novel insights into previously unrecognized mechanisms by which CLU maintains fluid-epithelial interface homeostasis, thereby preventing the onset of inflammatory conditions, especially where MMP-9 is actively involved.

Suppression of matrix metalloproteinase-9 expression in undifferentiated, non-apoptotic keratinocytes is abrogated by the cleavage of poly(ADP-ribose) polymerase-1

Matrix metalloproteinase (MMP)-9, an enzyme that degrades the extracellular matrix, has been implicated as a key enzyme in the process of tissue remodeling. This study demonstrates the regulation of MMP-9 transcription through a gene regulatory element in its promoter (the KRE-M9 element). The KRE-M9-binding protein was purified and identified as poly(ADP-ribose) polymerase-1 (PARP-1), which inhibits the transcription of MMP-9 similar to involucrin. This regulation occurs in non-apoptotic keratinocytes using the distinctive culture conditions of high and low Ca(2+) levels. PARP cleavage, which occurs during apoptosis, results in de-repression of MMP-9 promoter activity. These data clarify a new role of PARP-1 and suggest a physiologically relevant connection between caspase activation and MMP-9 expression.

N-Acetylglucosamine suppress collagenases activation in ultraviolet B-irradiated human dermal fibroblasts: Involvement of calcium ions and mitogen-activated protein kinases

BACKGROUND

N-Acetylglucosamine (GlcNAc) and its derivates have been utilized in dietary supplements and for therapeutic development due to their unique characteristics. GlcNAc is recognized primarily for its function as a precursor to hyaluronic acid, which plays a significant role in the structure and hydration of the extracellular matrix in skin, in both the epidermis and the dermis.

OBJECTIVE

We investigated the protective effects of GlcNAc on immortalized human skin fibroblasts (HS68) against UVB damage. We then explored the inhibitory effects of GlcNAc on UVB-induced collagenases and investigated the molecular mechanism underlying those effects.

METHODS

Those effects were assessed by semi-quantitative PCR, Western blotting and enzymatic activity assays.

RESULTS

GlcNAc increased the viability of, and inhibited ROS production in, HS68 cells exposed to UVB irradiation. Pre-treatment of HS68 cells with GlcNAc inhibited UVB-induced production of the collagenases MMP-1 and MMP-13. Western blot analysis further revealed that GlcNAc markedly suppressed the enhancement of collagen degradation in UVB-exposed HS68 cells. GlcNAc also suppressed UVB-induced activation of c-Jun, c-Fos and NF-κB and the phosphorylation of MAPKs and PI3K/Akt, upstream modulators of AP-1 and NF-κB. Moreover, GlcNAc decreased the UVB-induced influx of Ca(2+) into HS68 cells and the phosphorylation of Ca(2+)/calmodulin-dependent kinases (CaMKs).

CONCLUSION

The results indicate that GlcNAc inhibited UVB-induced collagenolytic MMP production by interfering with Ca(2+)-dependent Akt and MAPKs/AP-1 and NF-κB signaling. They may thus be potentially useful in the prevention and treatment of skin photoaging.

Suppression of phorbol-12-myristate-13-acetate-induced tumor cell invasion by bergamottin via the inhibition of protein kinase Cdelta/p38 mitogen-activated protein kinase and JNK/nuclear factor-kappaB-dependent matrix metalloproteinase-9 expression

Matrix metalloproteinase (MMP) plays an important role in the invasion and metastasis of cancer cells. The inhibitory effects of bergamottin, a cytochrome P450 inhibitor from Citrus paradis (grapefruit), on tumor invasion and migration and the possible mechanisms involved in this inhibition were investigated in human fibrosarcoma HT-1080 cells. Bergamottin reduced phorbol-12-myristate-13-acetate (PMA)-induced activation of MMP-9 and MMP-2 and further inhibited cell invasion and migration. Bergamottin suppressed PMA-enhanced expression of MMP-9 protein, mRNA and transcription activity levels through suppression of nuclear factor-kappaB (NF-kappaB) activation without changing the tissue inhibitor of metalloproteinase 1 level. Bergamottin also reduced PMA-enhanced MMP-2 expression through suppression of membrane-type 1 MMP, but did not alter tissue inhibitor of metalloproteinase 2 levels. Bergamottin inhibited PMA-induced NF-kappaB nuclear translocation and IkappaBalpha degradation, which are upstream of PMA-induced MMP-9 expression and invasion. Furthermore, bergamottin strongly repressed the PMA-induced phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase (JNK), which are dependent on the protein kinase C-delta pathway. In conclusion, we demonstrated that the anti-invasive effects of bergamottin might occur through inhibition of protein kinase C-delta, p38 mitogen-activated protein kinase, and JNK phosphorylation and reduction of NF-kappaB activation, leading to downregulation of MMP-9 expression. These results suggest that the suppression of MMP expression contributes, at least in part, to the antitumor activity of bergamottin.

The flavonoids apigenin and luteolin suppress ultraviolet A-induced matrix metalloproteinase-1 expression via MAPKs and AP-1-dependent signaling in HaCaT cells

BACKGROUND

Ultraviolet (UV) irradiation causes major changes in skin connective tissues as a result of the degradation of collagen, a major structural component of the extracellular matrix. This process is likely mediated by matrix metalloproteinases (MMPs). Such changes in collagenous skin tissues have been suggested to be causes of cutaneous aging and skin cancer.

OBJECTIVE

We investigated the protective effects of apigenin and luteolin on immortalized human keratinocytes (HaCaT) against UVA damage. We then explored the inhibitory effects of apigenin and luteolin on UVA-induced MMP-1 and investigated the molecular mechanism underlying those effects.

METHODS

HaCaT cells were treated with apigenin and luteolin for the indicated times followed by irradiation with UVA. Those effects were assessed by semi-quantitative PCR, Western blotting and enzymic activity assays.

RESULTS

These two compounds, at concentrations of 1-5μM, increased the viability of, and inhibited ROS production in HaCaT cells exposed to UVA irradiation. Pre-treatment of HaCaT cells with apigenin and luteolin also inhibited UVA-induced production of the collagenases MMP-1. They also suppressed UVA-induced expression of c-Jun and c-Fos and the phosphorylation of three MAP kinases, upstream modulators of AP-1. Furthermore, the same two flavonoids decreased the UVA-induced influx of Ca(2+) into HaCaT cells and the phosphorylation of Ca(2+)/calmodulin-dependent kinases (CaMKs).

CONCLUSION

The results indicate that apigenin and luteolin inhibited UVA-induced collagenolytic MMP-1 production by interfering with Ca(2+)-dependent MAPKs and AP-1 signaling. They may thus be potentially useful in the prevention and treatment of skin photoaging.

Metformin blocks migration and invasion of tumour cells by inhibition of matrix metalloproteinase-9 activation through a calcium and protein kinase Calpha-dependent pathway: phorbol-12-myristate-13-acetate-induced/extracellular signal-regulated kinase/activator protein-1

BACKGROUND AND PURPOSE

Population studies have revealed that treatment with the anti-diabetic drug metformin is significantly associated with reduced cancer risk, but the underlying mode of action has not been elucidated. The aim of our study was to determine the effect of metformin on tumour invasion and migration, and the possible mechanisms, using human fibrosarcoma HT-1080 cells.

EXPERIMENTAL APPROACH

We employed invasion, migration and gelatin zymography assays to characterize the effect of metformin on HT-1080 cells. Transient transfection assays were performed to gene promoter activities, and immunoblot analysis to study its molecular mechanisms of action.

KEY RESULTS

Metformin inhibited migration and invasion by HT-1080 cells at sub-toxic concentrations. In these cells, metformin also suppressed phorbol-12-myristate-13-acetate (PMA)-enhanced levels of matrix metalloproteinases-9 (MMP-9) protein, mRNA and transcription activity through suppression of activator protein-1 (AP-1) activation. In addition, metformin strongly repressed the PMA-induced phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and protein kinase C(PKC)alpha, whereas the phosphorylation of p38 mitogen-activated protein kinase was not affected by metformin. Metformin decreased the PMA-induced Ca(2+) influx. Furthermore, treatment with an intracellular Ca(2+) chelator (BAPTA-AM) or a selective calmodulin antagonist (W7) markedly decreased PMA-induced MMP-9 secretion and cell migration, as well as activation of ERK and JNK/AP-1.

CONCLUSIONS AND IMPLICATIONS

Metformin inhibited PMA-induced invasion and migration of human fibrosarcoma cells via Ca(2+)-dependent PKCalpha/ERK and JNK/AP-1-signalling pathways. Metformin therefore has the potential to be a potent anti-cancer drug in therapeutic strategies for fibrosarcoma metastasis.

A novel role for the TRPV1 channel in UV-induced matrix metalloproteinase (MMP)-1 expression in HaCaT cells

Transient receptor potential vanilloid type 1 (TRPV1) is a molecular sensor for detecting adverse stimuli, such as capsaicin, heat, and acid. TRPV1 has been localized in keratinocytes and is suggested to be a mediator of heat-induced matrix metalloproteinase-1 (MMP-1). With regard to the multimodal activation of TRPV1, we hypothesize that TRPV1 might also mediate UV-induced MMP-1 in keratinocytes. In HaCaT, a human keratinocyte cell line, we initially confirmed capsaicin-induced membrane current and Ca(2+) influx. UV irradiation induced slow and persistent calcium influx and increased membrane current, which was inhibited by TRPV1 inhibitors (capsazepine and ruthenium red). The UV-induced MMP-1 expression in HaCaT was also decreased by TRPV1 inhibitors and was facilitated by capsaicin. Knock-down of TRPV1 using siRNA transfection also decreased MMP-1 expression, as well as UV-induced Ca(2+) influx in HaCaT. UV failed to induce MMP-1 expression in HaCaT cells cultured in Ca(2+)-free media. Both the UV-induced increase in [Ca(2+)](i) and MMP-1 were suppressed by Gö6976 (a calcium-dependent PKC inhibitor), but not by rottlerin (a calcium-independent PKC inhibitor). In addition to a plausible role of TRPV1 in UV-induced MMP-1 expression, we showed that UV increased TRPV1 expression in both HaCaT cells and human skin in vivo. From these results, we suggest that UV-induced MMP-1 expression might be mediated in part by PKC-dependent activation of TRPV1 and subsequent Ca(2+)-influx in human keratinocytes. J. Cell. Physiol. 219: 766-775, 2009. (c) 2009 Wiley-Liss, Inc.

RECK negatively regulates matrix metalloproteinase-9 transcription

RECK, a glycosylphosphatidylinositol-anchored glycoprotein, inhibits the enzymatic activities of some matrix metalloproteinases (MMP), thereby suppressing tumor cell metastasis; however, the detailed mechanism is still obscure. In this study, we compared the gene expression profiles between mock- and RECK-transfected HT1080 cells and showed that RECK decreases MMP-9 mRNA levels but not other MMP mRNA levels. Moreover, treatment with RECK-specific siRNA increased MMP-9 mRNA in RECK-expressing cells. The promoter assay showed that MMP-9 promoter activity was suppressed by RECK and that RECK-mediated suppression of MMP-9 promoter activity requires 12-O-tetradecanoylphorbol-13-acetate-responsive element (TRE) and kappaB sites. Moreover, the binding ability of Fra-1 and c-Jun to TRE within the MMP-9 promoter region was suppressed by RECK. Thus, these results show that RECK is a negative regulator of MMP-9 transcription.

Mice that lack matrix metalloproteinase-9 display delayed wound healing associated with delayed reepithelization and disordered collagen fibrillogenesis

Matrix metalloproteinase- (MMP-9) is involved in processes that occur during cutaneous wound healing such as inflammation, matrix remodeling, and epithelialization, To investigate its role in healing, full thickness skin wounds were made in the dorsal region of MMP-9-null and control mice and harvested up to 14 days post wounding. Gross examination and histological and immunohistochemical analysis indicated delayed healing in MMP-9-null mice. Specifically, MMP-9-null wounds displayed compromised reepithelialization and reduced clearance of fibrin clots. In addition, they exhibited abnormal matrix deposition, as evidenced by the irregular alignment of immature collagen fibers. Despite the presence of matrix abnormalities, MMP-9-null wounds displayed normal tensile strength. Ultrastructural analysis of wounds revealed the presence of large collagen fibrils, some with irregular shape. Keratinocyte proliferation, inflammation, and angiogenesis were found to be normal in MMP-9-null wounds. In addition, VEGF levels were similar in control and MMP-9-null wound extracts. To investigate the importance of MMP-9 in wound reepithelialization we tested human and murine keratinocytes in a wound migration assay and found that antibody-based blockade of MMP-9 function or MMP-9 deficiency retarded migration. Collectively, our observations reveal defective healing in MMP-9-null mice and suggest that MMP-9 is required for normal progression of wound closure.

Matrix metalloproteinase-21 expression is associated with keratinocyte differentiation and upregulated by retinoic acid in HaCaT cells

In the skin, expression of several matrix metalloproteinases (MMPs) occurs in response to tissue injury, tumorigenesis, angiogenesis, apoptosis, and inflammation. The recently cloned MMP-21 has been implicated in skin development and various epithelial cancers. In this study, we found that it is also expressed by differentiated keratinocytes (KCs) in various benign skin disorders, in which it was not associated with KC apoptosis or proliferation, and in organotypic cultures. Furthermore, MMP-21 was induced in keratinocytes in association with increased calcium and presence of the differentiation marker filaggrin. In stably transfected A431 and HEK293 cell lines, MMP-21 increased invasion of cells but did not associate with increased apoptosis, proliferation, or epithelial-to-mesenchymal transition. Of various agents tested in HaCaT cell cultures, only retinoic acid (10(-6) M) and staurosporine (2.5 x 10(-8) M) upregulated MMP-21 mRNA and protein expression, whereas tumor promoters, hormones, or dexamethasone were without effect. Our results suggest that MMP-21 may be an important protease in the terminal differentiation of keratinocytes.

Autocrine actions of matrix metalloproteinase (MMP)-2 counter the effects of MMP-9 to promote survival and prevent terminal differentiation of cultured human keratinocytes

Cultured human keratinocytes produce matrix metalloproteinase (MMP)-2 and MMP-9. In this study, using small interfering RNA (siRNA) for MMP-2 or MMP-9, we investigated the functions of these two gelatinases in the regulation of survival by measuring growth, differentiation, apoptosis, and migration of cultured keratinocytes. MMP-2 siRNA treatment significantly decreased keratinocyte growth and migration, and stimulated apoptosis fourfold. In addition, MMP-2 siRNA caused a 70% reduction in keratin-14 (K14) and a fourfold increase in K10. In contrast, MMP-9 siRNA treatment exerted opposite effects on cell growth, apoptosis, and K10 expression. MMP-2 appears to act through the ERK MAP kinase and caspase-3 signaling pathways as evidenced by the 53% reduction in the level of phosphorylated ERK1/2 and threefold increase in phosphorylated p38 and stronger staining for active caspase-3 in response to MMP-2 siRNA. Dual fluorescent staining revealed that almost all cultured cells stained positive for MMP-2, with only a few scattered cells being positive for MMP-9. There were considerably more BrdU-positive cells following MMP-9 siRNA treatment, indicating that MMP-9 inhibited proliferation. In conclusion, MMP-2 stimulates keratinocyte survival whereas MMP-9 promotes terminal differentiation.

Transient receptor potential vanilloid-1 mediates heat-shock-induced matrix metalloproteinase-1 expression in human epidermal keratinocytes

Transient receptor potential vanilloid-1 (TRPV1), a heat-gated channel, was recently found on human keratinocytes and the activation of epidermal TRPV1 was known to induce release of proinflammatory mediators. However, the functional consequences of TRPV1 activation in cutaneous physiology and pathology have not been elucidated clearly. In this study, we investigated the role of TRPV1 on the matrix metalloproteinase (MMP)-1 expression induced by heat shock in human epidermal keratinocytes. Heat shock induced the expression of MMP-1 mRNA and protein in a temperature-dependent manner in an immortalized human keratinocyte cell line (HaCaT) and normal human epidermal keratinocytes (NHK). Heat-shock-induced MMP-1 expression was decreased by treatment of the TRPV1 inhibitors (capsazepine and ruthenium red) or knockdown of TRPV1 using RNA interference in HaCaT cells. Overexpression of TRPV1 greatly increased heat-shock-induced MMP-1 promoter activity in HEK 293 cells. Furthermore, direct activation of TRPV1 by capsaicin, a TRPV1 agonist, increased MMP-1 expression. We found that heat shock induced calcium influx through TRPV1 and that extracellular calcium was necessary for heat-shock-induced MMP-1 expression in HaCaT cells. Taken together, our results suggest that heat-shock-induced MMP-1 expression is mediated by activation of TRPV1 and is dependent on a calcium-dependent signaling process in human epidermal keratinocytes.

Calcium enhances mouse keratinocyte differentiation in vitro to differentially regulate expression of papillomavirus authentic and codon modified L1 genes

Here, we first wished to establish for mouse primary keratinocytes (KCs) the Ca(2+) concentrations that were associated with KC differentiation in vitro. Using the range of Ca(2+) concentrations (0-6 mM) to differentiate primary KCs in culture to varying extents for 2 days, we then examined how KC differentiation impacted on expression of papillomavirus (PV) native (Nat) and codon modified (Mod) L1 genes. L1 mRNAs transcribed from either Nat or Mod L1 genes were present in similar amounts in KCs exposed to six Ca(2+) concentrations. However, expression of the L1 proteins from two Mod L1 genes were down-regulated, with no L1 signal detected in KCs exposed to 6 mM Ca(2+). In contrast, L1 proteins expressed from the two Nat L1 genes were not detectable in KCs without Ca(2+), but dramatically up-regulated as the KC cultures exposed to Ca(2+) from 0.5 to 2 mM, then down-regulated in KCs exposed to Ca(2+) from 4 to 6 mM. The different regulatory roles of the Ca(2+) in L1 protein expression from Nat and Mod L1 genes in cultured KCs were confirmed by TGF-beta1 experiments. We observed that aminoacyl-tRNAs (aa-tRNAs) from the 2 mM Ca(2+)-treated KCs only significantly enhanced the Nat L1 mRNAs translation in vitro, suggesting that aa-tRNAs play a differentially regulatory role in translations of the PV Nat and Mod L1 mRNAs. Importantly, the Ca(2+) experimental model provides evidence that mouse primary KCs could be transiently infected by BPV1 virus to express L1 mRNA and protein, which is very useful for future HPV virus infection study.

Matrix metalloproteinase-19 expression in keratinocytes is repressed by transcription factors Tst-1 and Skn-1a: implications for keratinocyte differentiation

Matrix metalloproteinase-19 (MMP-19), unlike other members of the MMP family, is expressed in basal keratinocytes of intact epidermis whereas keratinocytes in suprabasal and higher epidermal layers express this enzyme only during cutaneous disorders. As the activity of MMP-19 effects proliferation, migration, and adhesion of keratinocytes we examined whether transcription factors involved in keratinocyte differentiation repress the expression of MMP-19. Using luciferase reporter assays, POU transcription factors Tst-1 (Oct-6) and Skn-1a (Oct-11) markedly downregulated the activity of MMP-19 promoter in COS-7 cells and HaCaT keratinocytes. Tst-1 alone was able to inhibit 85% of the promoter activity. Skn-1a exhibited a weak inhibitory effect although it synergistically increased effects of Tst-1. HaCaT cells stably transfected with Tst-1 showed a strong decrease of activity of MMP-19 promoter that correlated with suppression of MMP-19, cytokeratin 14 and 5, decreased cell proliferation, and altered expression of involucrin and loricrin. The expression of MMP-9 was also significantly reduced in Tst-1 expressing keratinocytes. MMP-2 was substantially affected during its activation whereas the expression of MMP-28 was unchanged. Our results suggest that Tst-1 and Skn-1a regulate expression of MMPs in keratinocytes and effect both the expression and activation of these proteolytic enzymes.

Tissue-specific expression of Clec2g in mice

Estrogens regulate the proliferation and differentiation of mouse vaginal epithelial cells. We examined the temporal and spatial expression of DDV10, a novel C-type lectin during stratification and cornification of the vaginal epithelium. DDV10 was expressed in vagina but not uterus in ovariectomized mice treated with 17beta-estradiol (E2). In mouse stomach, the expression of DDV10 was detected in pars proventricularis but not in pars glandularis. Furthermore, the DDV10 gene was found to possess two transcripts, a long form (DDV10) and a short form (OCILrP1, osteoclast inhibitory lectin-related protein 1). DDV10 mRNA but not OCILrP1 mRNA was expressed in the stratified and cornified epithelial tissues. DDV10 mRNA was first detected between 12 and 18 h after E2 treatment in the vaginal epithelium, and was detected in the vagina of the neonatally diethylstilbestrol (DES)-treated mouse. Recently, a unified name was registered in GenBank (C-type lectin domain family 2, member g; Clec2 g). Taken together, these data suggest that DDV10 is the long form of Clec2 g (Clec2g-L), and DDV10/Clec2g-L may play a role in the stratification and/or cornification of epithelial cells during differentiation.

Leptomycin B Reduces Matrix Metalloproteinase-9 Expression and Suppresses Cutaneous Inflammation

Matrix metalloproteinase-9 (MMP-9), a type of gelatinase, plays many roles in tissue metabolism, especially in inflammation, and many regulatory elements have been reported in the promoter region of its encoding gene. Leptomycin B, which regulates the nucleo-cytoplasmic trafficking of proteins, including transcription-factor-related ones, has the potential to exert important biological effects. The addition of leptomycin B to keratinocytes in culture had no effect on matrix metalloproteinase-2 (another gelatinase) but caused the selective down-regulation of MMP-9 during the stimulation of differentiation with high Ca(2+) or transforming growth factor-beta, as well as during the stimulation of inflammation by tumor necrosis factor-alpha or interleukin-1alpha. This down-regulation depended on multiple regulatory elements in the promoter of MMP-9 including KRE-M9 (which we have recently identified), and a classical 12-o-tetradecanoyl-phorbol-13-acetate-responsive element. The topical application of leptomycin B to murine skin also effectively suppressed inflammation, including MMP-9 expression, after ultraviolet B irradiation. These results suggest that the application of leptomycin B and/or its derivatives could be useful for treating many inflammatory conditions.

TNF-alpha regulates epithelial expression of MMP-9 and integrin alphavbeta6 during tumour promotion. A role for TNF-alpha in keratinocyte migration?

Mice deficient in TNF-alpha (TNF-alpha(-/-) mice) are resistant to skin carcinogenesis and expression of MMP-9 is inhibited in TNF-alpha(-/-) mice during skin tumour development. In the early stages of tumour promotion, MMP-9 protein initially localized to the follicular epidermis but subsequently began to accumulate in the interfollicular epidermis of wild-type but not TNF-alpha(-/-) mice. Inhibition of TNF-alpha or MMP-9 function reduced keratinocyte migration in vitro. In addition, a deficiency of TNF-alpha delayed re-epithelialization in vivo and this correlated with reduced MMP-9 expression. Collectively, these data suggest that MMP-9 regulates keratinocyte migration in a TNF-alpha-dependent manner. Expression profiling of genes that control cell adhesion and migration revealed markedly lower levels of the integrin subunits alphav and beta6 in TNF-alpha(-/-) compared with wild-type keratinocytes in vitro. alphavbeta6 expression was upregulated by keratinocytes in vitro and during tumour promotion in vivo in a TNF-alpha-dependent manner. Furthermore, alphavbeta6 blockade significantly inhibited keratinocyte migration and TNF-alpha-stimulated MMP-9 expression in vitro. These data illustrate a novel TNF-alpha-dependent mechanism for the control of alphavbeta6 expression and suggest one pathway for TNF-alpha regulation of MMP-9. Increased MMP-9 and alphavbeta6 expression may stimulate epithelial cell migration during tumour formation and may be one mechanism whereby TNF-alpha acts as an endogenous tumour promoter.

Calcium-induced Matrix Metalloproteinase 9 Gene Expression Is Differentially Regulated by ERK1/2 and p38 MAPK in Oral Keratinocytes and Oral Squamous Cell Carcinoma

Matrix metalloproteinases (MMPs) play an important role in the invasive behavior of a number of cancers including oral squamous cell cancer (OSCC), and increased expression of MMP-9 is correlated with invasive and metastatic OSCC. Because calcium is an important regulator of keratinocyte function, the effect of modulating extracellular calcium on MMP-9 expression in OSCC cell lines was evaluated. Increasing extracellular calcium induced a dose-dependent increase in MMP-9 expression in immortalized normal and premalignant oral keratinocytes, but not in two highly invasive OSCC cell lines. Differential activation of MAPK signaling was also induced by calcium. p38 MAPK activity was down-regulated, whereas ERK1/2 activity was enhanced. Pharmacologic inhibition of p38 MAPK activity or expression of a catalytically inactive mutant of the upstream kinase MAPK kinase 3 (MKK3) increased the calcium induced MMP-9 gene expression, demonstrating that p38 MAPK activity negatively regulated this process. Interestingly blocking p38 MAPK activity enhanced ERK1/2 phosphorylation, suggesting reciprocal regulation between the ERK1/2 and p38 MAPK pathways. Together these data support a model wherein calcium-induced MMP-9 expression is differentially regulated by the ERK1/2 and p38 MAPK pathways in oral keratinocytes, and the data suggest that a loss of this regulatory mechanism accompanies malignant transformation of the oral epithelium.

Matrix Metalloproteinase 9 Expression is Coordinately Modulated by the KRE-M9 and 12-O-Tetradecanoyl-Phorbol-13-Acetate Responsive Elements

To investigate the pathophysiologic role of matrix metalloproteinase 9 (MMP-9), we analyzed the mechanism of its transcriptional regulation in keratinocytes and in HT1080 fibrosarcoma cells in culture. The KRE-M9 element, which is located between the 12-O-tetradecanoyl-phorbol-13-acetate responsive element (TRE) and the transcription initiation site in the MMP-9 promoter, is essential for MMP-9 transcription in the absence of the TRE. The KRE-M9 binding protein, however, is shown to be a repressor of transcription rather than an activator; we found several times higher transcriptional activity when the KRE-M9 element was mutated. In contrast, activator protein 1 proteins (AP-1) are shown to activate transcription of MMP-9 by binding to the TRE, which is located adjacent to the KRE-M9 element. Moreover, we found that the KRE-M9 binding protein could serve as a differentiation repressing factor 1 (DRF-1) as shown by the decrease in levels of this protein with differentiation. In addition, the TRE binding protein is able to bind to the KRE-M9 to some extent. These results indicate that the coordinated modulation of MMP-9 transcription via the TRE and the KRE-M9 elements is important in epidermal and mesenchymal tissues. Our findings could facilitate consideration of the molecular mechanism in a variety of pathophysiologic conditions with which MMP-9 is involved.

The inhibition of MAPK pathway is correlated with down-regulation of MMP-9 secretion induced by TNF-alpha in human keratinocytes

MMP-9 (92 kDa) is the major gelatinase able to degrade collagen IV, secreted by keratinocytes that are actively involved in wound-healing or tumorigenesis. Since the invasive phenotype of cancers is dependent on MMP-9 expression, it appeared of interest to precisely characterize which signal transduction pathways activated by TNF-alpha are involved in MMP-9 up-regulation induced by TNF-alpha. In HaCaT cells, activation of MMP-9 occurs at the transcriptional level. Inhibition of the MAPK pathway using specific inhibitors of the Ras, Raf, MEK1/2, and Erk1/2 cascade was correlated with a marked inhibition of MMP-9 activity, as determined by gene and protein expression. MAPK pathway activation via TNF-alpha was confirmed by marked AP-1 activation detected in EMSA. Under our experimental conditions, p38 MAPK and SAPK/JNK pathways were not activated. Gene and protein expression of other MMPs that regulate MMP-9, such as MMP-1 and MMP-13, were also up-regulated by TNF-alpha and inhibited by UO126, providing evidence that the MAPK pathway plays a fundamental role in the regulation of MMP-9 secretion by keratinocytes. As TNF-alpha is known to be a main activator of NF-kappaB pathway, the effects of campthothecin and caffeic acid were investigated, such as, TNF-alpha campthothecin up-regulated MMP-9 activity but caffeic acid only weakly inhibited MMP-9 activation induced by TNF-alpha. However, NF-kappaB is activated as shown from immunostaining data, a nuclear staining and higher Western blotting expression of p50 and p65 NF-kappaB subunits were detected after TNF-alpha treatment. A higher specific signal was also detected in EMSA for TNF-alpha-treated cells.

Induction of matrix metalloproteinase-9 secretion from human keratinocytes in culture by ultraviolet B irradiation

BACKGROUND

Matrix metalloproteinases (MMPs) are known as important enzymes involved in tissue metabolism. Among them, MMP-2 and MMP-9 are termed gelatinases, but their specific roles in vivo are still unknown, including their expression patterns following ultraviolet (UV) irradiation.

OBJECTIVE

To elucidate the effects of UV irradiation on the skin, we analyzed the expression of MMP-2 and MMP-9 by primary human keratinocytes in culture.

METHODS

We evaluated the enzymatic functions of MMP-2 and MMP-9 by gelatin-zymography, and of MMP-9 expression by immunofluorescence, using cultured keratinocytes after UV irradiation.

RESULTS

The secretion of MMP-2 (72 kDa) remained at low levels under all conditions examined. Although MMP-9 (92 kDa) secretion was not induced by UVA, it was stimulated by UVB irradiation in a dose-dependent manner. In addition, an enzyme-linked immunosorbent assay showed the tendency to increase for the involucrin expression following UVB exposure. Cell viability was decreased by UVB irradiation in contrast to the induction of MMP-9 and involucrin.

CONCLUSION

These results suggest that the induction of MMP-9 secretion is related to the inflammation including apoptosis of keratinocytes resulting from UVB irradiation.

Synergistic effect of retinoic acid and dehydroepiandrosterone on differentiation of human neuroblastoma cells

Retinoic acid (RA) affects many cell types by either promoting their survival or inducing their differentiation. Dehydroepiandrosterone (DHEA), a precursor for both androgenic and estrogenic steroids and abundantly produced by brain, is known as an inhibitor of cell proliferation. Differentiation of a human neuroblastoma cell line (SK-N-BE) was evaluated measuring growth rate, motility, neurite extension and GAP-43 expression. We report that DHEA enhances the differentiating effect of RA on neuroblastoma cells via a signalling that is not RA receptor-mediated. Instead, we show a differential expression of matrix metalloproteinases: RA enhances the activity of MMP-2, whereas MMP-9 expression is up-regulated by DHEA. The concerted modulation of these proteinases may support the neurite outgrowth observed after co-treatment with the two drugs.

Calcium regulation of matrix metalloproteinase-mediated migration in oral squamous cell carcinoma cells

Activation of matrix metalloproteinase 2 (MMP-2) has been shown to play a significant role in the behavior of cancer cells, affecting both migration and invasion. The activation process requires multimolecular complex formation involving pro-MMP-2, membrane type 1-MMP (MT1-MMP), and tissue inhibitor of metalloproteinases-2 (TIMP-2). Because calcium is an important regulator of keratinocyte function, we evaluated the effect of calcium on MMP regulation in an oral squamous cell carcinoma line (SCC25). Increasing extracellular calcium (0.09-1.2 mm) resulted in a dose-dependent increase in MT1-MMP-dependent pro-MMP-2 activation. Despite the requirement for MT1-MMP in the activation process, no changes in MT1-MMP expression, cell surface localization, or endocytosis were apparent. However, increased generation of the catalytically inactive 43-kDa MT1-MMP autolysis product and decline in the TIMP-2 levels in conditioned media were observed. The decrease in TIMP-2 levels in the conditioned media was prevented by a broad spectrum MMP inhibitor, suggesting that calcium promotes recruitment of TIMP-2 to MT1-MMP on the cell surface. Despite the decline in soluble TIMP-2, no accumulation of TIMP-2 in cell lysates was seen. Blocking TIMP-2 degradation with bafilomycin A1 significantly increased cell-associated TIMP-2 levels in the presence of high calcium. These data suggest that the decline in TIMP-2 is because of increased calcium-mediated MT1-MMP-dependent degradation of TIMP-2. In functional studies, increasing calcium enhanced MMP-dependent cellular migration on laminin-5-rich matrix using an in vitro colony dispersion assay. Taken together, these results suggest that changes in extracellular calcium can regulate post-translational MMP dynamics and thus affect the cellular behavior of oral squamous cell carcinoma.

Estrogen-independent expression of neuropsin, a serine protease in the vagina of mice exposed neonatally to diethylstilbestrol

Perinatal treatment of female mice with natural or synthetic estrogens including diethylstilbestrol (DES) results in estrogen-independent persistent proliferation and cornification of the vaginal epithelium. However, the molecular mechanisms of the estrogen-independent changes have not been elucidated. To analyze the mechanism of estrogen-independent cell proliferation and cornification of the vaginal epithelium, we used differential display and determined specific genes expressed in neonatally DES-treated vagina. A candidate clone that designated DDV5 was identical to the serine protease, neuropsin that is reportedly expressed in the mouse central nervous system. We then analyzed the expression pattern of DDV5/neuropsin using Northern blot analysis. We found: (1). DDV5/neuropsin mRNA is expressed in vaginae from neonatally DES-treated ovariectomized mice but not in vaginae from ovariectomized control mice, (2). its expression is not detected in uteri from neonatally DES-treated mice, (3). DDV5/neuropsin is expressed in vaginae from normal intact mice during estrus. Furthermore, we found that DDV5/neuropsin mRNA rapidly decreased in vaginae after ovariectomy. DDV5/neuropsin was detected in vaginae from ovariectomized mice 48 h after estrogen treatment. These results suggest that DDV5/neuropsin is expressed in estrogen-stimulated mouse vagina, and its gene expression is regulated by estrogen. Neonatal DES exposure affects transcriptional control of DDV5/neuropsin in the mouse vagina, which results in persistent expression of DDV5/neuropsin even after ovariectomy, thus, DDV5/neuropsin may play a role in estrogen-independent persistent proliferation and cornification of the vaginal epithelium. Using in situ hybridization method, we found DDV5/neuropsin mRNA localized in epithelial cells but not stromal cells in vaginae. This is the first report on the gene expression of a serine-protease neuropsin in the mouse vagina, and as a marker of the estrogen-independent persistent proliferation and cornification of the vaginal epithelium.

Interferons inhibit tumor necrosis factor-alpha-mediated matrix metalloproteinase-9 activation via interferon regulatory factor-1 binding competition with NF-kappa B

Enhanced expression of matrix metalloproteinase-9 (MMP-9) correlates with invasion during tumor progression. Interferons (IFNs) inhibit MMP-9 activation in response to tumor necrosis factor-alpha (TNF-alpha), and the latter activates the MMP-9 gene through NF-kappaB. Understanding the molecular basis for MMP-9 inhibition may provide tools to control cell invasion. The data reported here show the critical role of interferon regulatory factor-1 (IRF1) in the inhibition of MMP-9. (i) IFN treatment suppresses TNF-alpha-induced MMP-9 reporter activity in STAT1(+/+) cells but not in STAT1(-/-) cells. (ii) IRF1 transfection blocks TNF-alpha-mediated MMP-9 activation. (iii) IFNs phosphorylate STAT1 and induce IRF1 but do not affect Ikappa-B degradation nor NF-kappaB nuclear translocation. (iv) Nuclear NF-kappaB (p50/p65) and IRF1, but not STAT1, bind to the MMP-9 promoter region containing an IFN-responsive-like element overlapping the NF-kappaB-binding site. (v) Recombinant IRF1, although unable to bind to an NF-kappaB consensus sequence, competes with NF-kappaB proteins for binding to the MMP-9 promoter. (vi) Conversely recombinant p50/p65 proteins reduce IRF1-DNA binding. (vii) In cells cotransfected with IRF1 and/or p65 expression vectors, an excess of IRF1 reduces MMP-9 reporter activity, whereas an excess of p65 blocks the inhibitory effect of IFN-gamma. Thus, in contrast to the known synergism between IRF1 and NF-kappaB, our data identify a novel role for IRF1 as a competitive inhibitor of NF-kappaB binding to the particular MMP-9 promoter context.