Down-regulation of tissue inhibitor of matrix metalloprotease-1 (TIMP-1) in aged human skin contributes to matrix degradation and impaired cell growth and survival

In vitro and in vivo suppression of cellular activity by guanidinoethyl disulfide released from hydrogel microspheres composed of partially oxidized hyaluronan and gelatin

This paper describes the preparation of oxidized hyaluronan crosslinked gelatin microspheres for drug delivery. Microspheres were prepared by a modified water-in-oil-emulsion crosslinking method, where three-dimensional crosslinked hydrogel microspheres formed in the absence of any extraneous crosslinker. SEM analyses of the microspheres showed rough surfaces in their dried state with an average diameter of 90 microm. Lyophilization of fully swollen microspheres revealed a highly porous structure. Guanidinoethyl disulfide (GED) was used as a model drug for incorporation into the microspheres; encapsulation of GED was confirmed by HPLC. There was an inverse correlation between the diameters of the microspheres with their GED loading. Macrophage was used as a model cell to evaluate the in vitro efficacy of GED release from the microspheres. The in vivo efficacy of the microspheres was further validated in a mouse full-thickness transcutaneous dermal wound model through suppression of cell infiltration.

Amla (Emblica officinalis Gaertn.) extract promotes procollagen production and inhibits matrix metalloproteinase-1 in human skin fibroblasts

AIM OF THE STUDY

Emblica officinalis Gaertn., commonly known as amla, is a rich dietary source of vitamin C, minerals and amino acids, and also contains various phenolic compounds. Amla extract is also known to exhibits potent antioxidant properties and to provide protection for human dermal fibroblasts against oxidative stress, and therefore it is thought to be useful for natural skin care. In this study, we investigated the effects of amla extract on human skin fibroblasts, especially for production of procollagen and matrix metalloproteinases (MMPs), in vitro.

MATERIALS AND METHODS

Mitochondrial activity of human skin fibroblasts were measured by WST-8 assay. Quantification of procollagen, MMPs, and Tissue inhibitor of metalloproteinase-1 (TIMP-1) released from human skin fibroblasts were performed by immunoassay technique.

RESULTS AND CONCLUSIONS

Amla extract stimulated proliferation of fibroblasts in a concentration-dependent manner, and also induced production of procollagen in a concentration- and time-dependent manner. Conversely, MMP-1 production from fibroblasts was dramatically decreased, but there was no evident effect on MMP-2. TIMP-1 was significantly increased by amla extract. From these results, it appears that amla extract works effectively in mitigative, therapeutic and cosmetic applications through control of collagen metabolism.

Cellular senescence and organismal aging

Cellular senescence, first observed and defined using in vitro cell culture studies, is an irreversible cell cycle arrest which can be triggered by a variety of factors. Emerging evidence suggests that cellular senescence acts as an in vivo tumor suppression mechanism by limiting aberrant proliferation. It has also been postulated that cellular senescence can occur independently of cancer and contribute to the physiological processes of normal organismal aging. Recent data have demonstrated the in vivo accumulation of senescent cells with advancing age. Some characteristics of senescent cells, such as the ability to modify their extracellular environment, could play a role in aging and age-related pathology. In this review, we examine current evidence that links cellular senescence and organismal aging.

Self-crosslinkable hydrogels composed of partially oxidized hyaluronan and gelatin: in vitro and in vivo responses

Self-crosslinkable hydrogels had been formulated from two precursors, partially oxidized hyaluronan (oHA) and gelatin. The physicochemical properties of the resulting hydrogels have been elucidated by instrumental analyses (FTIR, SEM, and rheometry). These hydrogels were highly porous with an average pore size of 60 microm, and evidently, accommodative to cell infiltration. Increasing the oxidation degree of oHA resulted in corresponding increases in hydrogels' storage moduli and decreases in water uptake. Dermal fibroblasts were used to study the cell-hydrogel interactions in vitro. Both the hydrogels and their degradation byproducts are biocompatible as indicated by long-term cell viability assay. In addition, significant amount of cells migrated into the hydrogels and they aligned into highly organized arrays. When cultured with cells, the hydrogels underwent degradation within 4 weeks depending on composition with obvious loss of cohesiveness over time. The good biocompatibility and biodegradability of oHA/gelatin hydrogel were further demonstrated in mice subdermal implantations. Lastly, in vitro and in vivo depositions of extracellular matrix in hydrogels by cells were demonstrated by SEM analyses.

Screening of senescence-associated genes with specific DNA array reveals the role of IGFBP-3 in premature senescence of human diploid fibroblasts

Repeated exposures to sublethal concentrations of tert-butylhydroperoxide and ethanol trigger premature senescence of WI-38 human diploid fibroblasts. We found 16 replicative senescence-related genes with similar alterations in expression level in replicative senescence and two models of stress-induced premature senescence. Among these genes was IGFBP-3. Using a siRNA approach, we showed that IGFBP-3 regulates the appearance of several biomarkers of senescence after repeated exposures of WI-38 fibroblasts to tert-butylhydroperoxide and ethanol.

Mechanically strong double network photocrosslinked hydrogels from N,N-dimethylacrylamide and glycidyl methacrylated hyaluronan

Hyaluronan (HA) is a natural polysaccharide abundant in biological tissues and it can be modified to prepare biomaterials. In this work, HA modified with glycidyl methacrylate was photocrosslinked to form the first network (PHA), and then a series of highly porous PHA/N,N-dimethylacrylamide (DAAm) hydrogels (PHA/DAAm) with high mechanical strength were obtained by incorporating a second network of photocrosslinked DAAm into PHA network. Due to the synergistic effect produced by double network (DN) structure, despite containing 90% of water, the resulting PHA/DAAm hydrogel showed a compressive modulus and a fracture stress over 0.5 MPa and 5.2 MPa, respectively. Compared to the photocrosslinked hyaluronan single network hydrogel, which is generally very brittle and fractures easily, the PHA/DAAm hydrogels are ductile. Mouse dermal fibroblast was used as a model cell line to validate in vitro non-cytotoxicity of the PHA/DAAm hydrogels. Cells deposited extracellular matrix on the surface of these hydrogels and this was confirmed by positive staining of Type I collagen by Sirius Red. The PHA/DAAm hydrogels were also resistant to biodegradation and largely retained their excellent mechanical properties even after 2 months of co-culturing with fibroblasts.

Impact of intense pulse light irradiation on BALB/c mouse skin-in vivo study on collagens, matrix metalloproteinases and vascular endothelial growth factor

Our aim was to investigate the effects of intense pulsed light (IPL) on collagen expression in BALB/c mouse skin and confirm its relative molecular mechanisms. The dorsal skin of BALB/c mice was irradiated by IPL. Before treatment and from 1 day to 8 weeks (1 day, 3 days, 5 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks and 8 weeks) after treatment, the irradiated skin specimens were examined. The histology showed dermis thickening, accompanied with increased collagen and better organization. After IPL irradiation from 2 W up to 8 W, the staining of collagen types I and III in the IPL-treated groups was stronger than in the sham groups (P < 0.05), and the mRNA expression levels of the procollagen types I and III had also increased (P < 0.05). The up-regulation effects of IPL irradiation were time-dependent. The mRNA expression levels of matrix metalloproteinase (MMP)-1 and MMP-2 decreased progressively after IPL irradiation at 2 W up to 8 W (P < 0.05), and this down-regulation effect of IPL was also time-dependent. However, the mRNA expression of vascular endothelial growth factor (VEGF) had shown no obvious change by the end of the experiment (P > 0.05). Taking these factors together, we can conclude that IPL irradiation can not only enhance new collagen production, but also decrease collagen degradation in photo-rejuvenation mechanisms in mouse skin.

Dermatoporosis: A Chronic Cutaneous Insufficiency/Fragility Syndrome

BACKGROUND

Skin aging has long been considered only as a cosmetic problem. With the increase in lifespan, we are now more often experiencing a further dimension of skin aging, which is no longer only cosmetic, but also functional, in the sense that the skin has lost its protective mechanical function. Dermatoporosis is the name proposed to capture, in a holistic approach, all the aspects of this chronic cutaneous insufficiency/fragility syndrome.

OBSERVATIONS

In this paper, we review the clinical aspects of dermatoporosis, its histological features and the current understanding of its etiological factors. The clinical manifestations of dermatoporosis comprise (i) morphological markers of fragility--rather trivial--such as senile purpura, stellate pseudoscars and skin atrophy, and (ii) functional expression of skin fragility resulting from minor traumas such as frequent skin laceration, delayed wound healing, nonhealing atrophic ulcers and subcutaneous bleeding with the formation of dissecting hematomas leading to large zones of necrosis. Dissecting hematomas bear significant morbidity needing hospitalization and urgent surgical procedures. Molecular mechanisms implying hyaluronate-CD44 pathways in the control and maintenance of epithelial growth and the viscoelastic properties of the extracellular matrix offer new opportunities for preventive intervention.

CONCLUSION

We propose to group the different manifestations and implications of this syndrome under the umbrella term of 'dermatoporosis', because we think it will help to capture the understanding of health professionals that, as osteoporosis, 'dermatoporosis' should be prevented and treated to avoid complications. Dermatologists should be aware of this emerging syndrome and function as key players in prevention and therapy. Randomized clinical trials should demonstrate which intervention may best prevent and/or reverse dermatoporosis.

Retinol inhibits the invasion of retinoic acid-resistant colon cancer cells in vitro and decreases matrix metalloproteinase mRNA, protein, and activity levels

Retinol inhibits the growth of all-trans-retinoic acid (ATRA)-resistant human colon cancer cell lines through a retinoic acid receptor (RAR)-independent mechanism. The objectives of the current study were to determine if retinol inhibited the invasion of ATRA-resistant colon cancer cells independent of RAR and the effects of retinol on matrix metalloproteinases (MMPs). Retinol inhibited the migration and invasion of two ATRA-resistant colon cancer cell lines, HCT-116 and SW620, in a dose-dependent manner. To determine if transcription, particularly RAR-mediated transcription, or translation of new genes was required for retinol to inhibit cell invasion, cells were treated with retinol and cycloheximide, actinomycin D, or an RAR pan-antagonist. Treatment of cells with retinol and cycloheximide, actinomycin D, or an RAR pan-antagonist did not block the ability of retinol to inhibit cell invasion. In addition, retinol decreased MMP-1 mRNA levels in both cell lines, MMP-2 mRNA levels in the SW620 cell line, and MMP-7 and -9 mRNA levels in the HCT-116 cell line. Retinol also decreased the activity of MMP-2 and -9 and MMP-9 protein levels while increasing tissue inhibitor of MMP-1 media levels. In conclusion, retinol reduces the metastatic potential of ATRA-resistant colon cancer cells via a novel RAR-independent mechanism that may involve decreased MMP mRNA levels and activity.

Protein oxidation and degradation during aging: role in skin aging and neurodegeneration

During aging, the products of oxidative processes accumulate and might disturb cellular metabolism. Among them are oxidized proteins and protein aggregates. On the other hand, in a functioning metabolic system oxidized proteins are degraded, mainly by the proteasome. During aging, however, proteasome activity declines. Therefore, the ability to degrade oxidized proteins is attenuated. The following review summarises the accumulation of oxidized proteins and the decline of the proteasomal system during skin and brain aging including some age-related neurodegenerative processes. The role of protein aggregates will be discussed as a potential reason for the accelerated dysfunction of tissue during aging.

Photoaging: Mechanisms and repair

Aging is a complex, multifactorial process resulting in several functional and esthetic changes in the skin. These changes result from intrinsic as well as extrinsic processes, such as ultraviolet radiation. Recent advances in skin biology have increased our understanding of skin homeostasis and the aging process, as well as the mechanisms by which ultraviolet radiation contributes to photoaging and cutaneous disease. These advances in skin biology have led to the development of a diversity of treatments aimed at preventing aging and rejuvenating the skin. The focus of this review is the mechanism of photoaging and the pathophysiology underlying the treatments specifically designed for its prevention and treatment.

LEARNING OBJECTIVES

At the conclusion of this learning activity, participants should be familiar with the mechanism of photoaging, the treatments for photoaging, and the data that supports the use of these treatments.

UVA-mediated down-regulation of MMP-2 and MT1-MMP coincides with impaired angiogenic phenotype of human dermal endothelial cells

UVA irradiation, dose-dependently (5-20 J/cm2), was shown to impair the morphogenic differentiation of human microvascular endothelial cells (HMECs) on Matrigel. Parallely, UVA down-regulated the expression of MMP-2 and MT1-MMP, both at the protein and the mRNA levels. On the contrary, the production of MMP-1 and TIMP-1 by HMECs increased following UVA treatment. The inhibitory effect of UVA on MMP expression and pseudotubes formation was mediated by UVA-generated singlet oxygen (1O2). The contribution of MT1-MMP, but not TIMP-1, to the regulation of HMECs' angiogenic phenotype following UVA irradiation was suggested using elastin-derived peptides and TIMP-1 blocking antibody, respectively.

Cell expression of MMP-1 and TIMP-1 in co-cultures of human gingival fibroblasts and monocytes: the involvement of ICAM-1

Matrix metalloproteinase-1 (MMP-1) plays an important role in the degradation of collagen in inflammatory diseases. The aim of this study was to investigate the cellular expression of MMP-1 and its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), in gingival fibroblasts co-cultured with monocytes and the possible mediating role of intercellular adhesion molecule-1 (ICAM-1). In co-cultures, the expression of MMP-1 and TIMP-1 increased in fibroblasts, but not in monocytes, although the number of MMP-1+ and TIMP-1+ adhered monocytes increased. Moreover, ICAM-1 expression in both fibroblasts and adhered monocytes increased. In the presence of an anti-ICAM-1 antibody, the expression of MMP-1 in fibroblasts decreased whereas the number of TIMP-1+ adhered monocytes increased. The p38 MAPK inhibitor SB203580 reduced MMP-1 expression in fibroblasts, as well as ICAM-1 expression in both fibroblasts and adhered monocytes. The results suggest that co-culture with monocytes enhances cellular expression of MMP-1 and TIMP-1 in gingival fibroblasts, and that the increased MMP-1 expression, in contrast to TIMP-1, is partly mediated by the adhesion molecule ICAM-1 and the p38 MAPK signal pathway.

The effects of epigallocatechin-3-gallate on extracellular matrix metabolism

BACKGROUND

Anti-oxidants have attracted a lot of interest on account of their function to protect the skin from oxidative stress by ultraviolet (UV) radiation.

OBJECTIVE

This study examined the effects of epigallocatechin-3-gallate (EGCG), which is a green tea extract, on the extracellular matrix (ECM) changes induced by UV radiation and showed the comparative results with retinoic acid (RA).

METHODS

The ECM metabolism is tightly controlled by the collagen degrading matrix metalloprotienases (MMPs) and their tissue inhibitors (TIMPs). Therefore, the expression of MMPs and TIMP-1 was investigated to evaluate the effects of EGCG and RA. Artificial skin was made using three-dimensionally cultured keratinocytes on a collagen matrix populated with fibroblasts. EGCG and RA were added into the medium of the fibroblasts and keratinocytes culture and also applied topically on artificial skins prior to UVA irradiation. The MMPs and TIMP-1 expression levels were measured using Western blot and a zymogram.

RESULTS

EGCG, like RA, decreased the level of MMPs production and increased TIMP-1 expression level. However, EGCG suppressed the activities of the gelatinases and augmented the expressions of the TIMP-1 more than RA did. RA decreased the MMP-1 and MMP-3 expression levels to a greater extent than EGCG. ECM alterations as a result of UVA appeared to be prevented more effectively using the EGCG treatment.

CONCLUSION

EGCG can reverse the ECM degradation induced by UV even with a topical application of a practical-use concentration. In particular, EGCG proved to be much more effective in ROS-related conditions, such as UVA exposure.

Diffuse expression of heparan sulfate proteoglycan and connective tissue growth factor in fibrous septa with many mast cells relate to unresolving hepatic fibrosis of congenital hepatic fibrosis

BACKGROUND AND AIMS

Congenital hepatic fibrosis (CHF) is characterized by dense portal/septal fibrosis and bile duct proliferation and tortuosity. In this study, the roles and significance of fibrosis-related cells and molecules in the process of progressive and unresolving fibrosis of CHF were examined in comparison with other fibrotic liver diseases.

METHODS

Seven CHF livers were examined, and a total of 74 control livers (chronic viral hepatitis (CVH), alcoholic fibrosis/cirrhosis (F/C), extrahepatic biliary obstruction and livers showing non-specific reactive changes) were used as controls. All of these livers were wedge biopsied or surgically resected ones, and were formalin fixed and paraffin embedded. In addition to histologic observations, expression of heparan sulfate proteoglycan (HSPG), connective tissue growth factor (CTGF), mast cell-specific tryptase, alpha-smooth muscle actin for activated hepatic stellate cells (HSC) or myofibroblasts (MF) were immunohistochemically surveyed. HSPG and CTGF at mRNA were also examined by in situ hybridization.

RESULTS

Portal/septal fibrosis of CHF were mature collagenous and elastic fiber poor, when compared with controls. HSPG and CTGF were diffusely abundant in fibrous portal tracts/septa in CHF, while they were more or less accentuated at periportal areas in alcoholic F/C and CVH. In CHF, the number of interface and portal/septal MF was increased from mild-to-moderate degree, while their increase was moderate to marked in alcoholic F/C and CVH, particularly F3/F4. While activated HSC were frequent in alcoholic F/C and CVH and they were continuous with interface MF, activated HSC in CHF were scanty. Instead, mast cells were increased in portal/septal fibrosis of CHF. Portal mononuclear cells and endothelial cells were positive for HSPG mRNA, and mononuclear cells for CTGF mRNA, and such cells were accentuated around proliferated bile ducts and ductules in CHF.

CONCLUSIONS

Abundant CTGF retained diffusely in HSPG in the fibrous portal tracts/septa may be responsible for non-resolving hepatic fibrosis in CHF, and many mast cells and portal MF not related to HSC may causally relate to such characteristic finding in CHF.

Beneficial and detrimental influences of tissue inhibitor of metalloproteinase-1 (TIMP-1) in tumor progression

Tissue inhibitor of metalloproteinase-1 (TIMP-1) is one representative of the natural matrix metalloproteinase (MMP) inhibitor family, encompassing four members. It inhibits all MMPs, except several MT-MMPs, and a disintegrin with a metalloproteinase domain (ADAM)-10 with Kis < nM. Unexpectedly, its upregulation was associated to poor clinical outcome for several cancer varieties. Such finding might be related to the growth-promoting and survival activities of TIMP-1 for normal and cancer cells. In most cases, such properties are MMP-independent and binding of TIMP-1 to an unknown receptor system can trigger JAK (or FAK)/PI3 kinase/Akt/bad-bclX2 (erythroid, myeloid, epithelial cell lines) or Ras/Raf1/FAK (osteosarcoma cell line) signaling pathways. The relationship between viral infection and TIMP-1 expression is here underlined. Thus, TIMP-1 might display a dual influence on tumor progression; either beneficial by inhibiting MMPs as MMP-9 and by impairing angiogenesis or detrimental by favoring cancer cells growth or survival. We consider that the proMMP-9/TIMP-1 balance is of critical importance in early events of tumor progression, and might show promise as diagnostic and prognostic marker of malignancy.

Differential response of TIMP-3 null mice to the lung insults of sepsis, mechanical ventilation, and hyperoxia

An imbalance in matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) leads to excessive or insufficient tissue breakdown, which is associated with many disease processes. The TIMP-3 null mouse is a model of MMP/TIMP imbalance, which develops air space enlargement and decreased lung function. These mice responded differently to cecal ligation and perforation (CLP)-induced septic lung injury than wild-type controls. The current study addresses whether the TIMP-3 knockout lung is susceptible to different types of insults or only those involving sepsis, by examining its response to lipopolysaccharide (LPS)-induced sepsis, mechanical ventilation (MV), and hyperoxia. TIMP-3 null noninjured controls of each insult consistently demonstrated significantly higher compliance vs. wild-type mice. Null mice treated with LPS had a further significantly increased compliance compared with untreated controls. Conversely, MV and hyperoxia did not alter compliance in the null lung. MMP abundance and activity increased in response to LPS but were generally unaltered following MV or hyperoxia, correlating with compliance alterations. All three insults produced inflammatory cytokines; however, the response of the null vs. wild-type lung was dependent on the type of insult. Overall, this study demonstrated that 1) LPS-induced sepsis produced a similar response in null mice to CLP-induced sepsis, 2) the null lung responded differently to various insults, and 3) the null susceptibility to compliance changes correlated with increased MMPs. In conclusion, this study provides insight into the role of TIMP-3 in response to various lung insults, specifically its importance in regulating MMPs to maintain compliance during a sepsis.

The role of matrix metalloproteinases in the morphogenesis of the cerebellar cortex

The morphogenesis of the cerebellar cortex depends on intrinsic genetic programs as well as orchestrated cell-cell/cell-extracellular matrix (ECM) interactions. The matrix metalloproteinase (MMP) family comprises of more than 20 members that catalyze the degradation of all the protein constituents of the ECM. These proteolytic endopeptidases mediate cell-cell/cell-ECM interactions by remodeling the ECM and modulating the activity of membrane-associated receptors. The activity of MMPs is negatively controlled by the tissue inhibitors of metalloproteinases (TIMPs). The MMPs and TIMPs regulate diverse neuronal functions including migration, process extension and synaptic plasticity. MMP-2, -3, -9, membrane type 5-MMP (MT5-MMP), TIMP-1, -2 and -3 are expressed in the developing cerebellum. The spatiotemporal pattern of expression/activity of these enzymes suggests that they play a role in the development of the cerebellar cortex. Blockage of MMP-2/-9 activity by specific inhibitors or blocking antibody, as well as using MMP-9 knock-out mice, clearly establishes that MMP-2/-9 participates in the regulation of morphogenesis of the cerebellum. The potential contributions of these enzymes to granule neuron migration, Purkinje cell dendritogenesis and synaptogenesis are discussed.

Dermal fibroblasts from pseudoxanthoma elasticum patients have raised MMP-2 degradative potential

Cultured fibroblasts from the dermis of normal subjects and of Pseudoxanthoma elasticum (PXE) patients were analysed for enzyme activity, protein and mRNA expression of metalloproteases (MMP-2, MMP-3, MMP-9, MT1-MMP) and of their specific inhibitors (TIMP-1, TIMP-2 and TIMP-3). MMP-3, MMP-9 and TIMP-3 mRNAs and proteins failed to be detected in both the medium and the cell layer of both controls and PXE patients. MMP-2 mRNA was significantly more expressed in PXE than in control cell lines, whereas MT1-MMP, TIMP-1 and TIMP-2 mRNAs appeared unchanged. MMP-2 was significantly higher in the cell extracts from PXE fibroblasts than in control cells, whereas differences were negligible in the cell medium. Data suggest that PXE fibroblasts have an increased proteolytic potential, and that MMP-2 may actively contribute to connective tissue alterations in this genetic disorder.