proMMP-2 Activation Research Articles

Escherichia coli induced matrix metalloproteinase-9 activity and type IV collagen degradation is regulated by progesterone in human maternal decidual

BackgroundEscherichia coli (E. coli) is one of the main bacteria associated with preterm premature rupture of membranes by increasing pro-matrix metalloproteinase 9 (proMMP-9) and degradation of type IV collagen in human feto-maternal interface (HFMi). proMMP-9 is regulated by progesterone (P4) but it is unclear whether P4 inhibits proMMP in human maternal decidual (MDec). This study aimed to determine a role of P4 on proMMP-2 and − 9 and type IV collagen induced by E. coli infection in MDec.MethodsNine HFMi were mounted in a Transwell system. MDec was stimulated with P4 or E. coli for 3-, 6-, or 24-hours. proMMP-2, -9 and type IV collagen were assessed.ResultsGelatin zymography revealed an increase in proMMP-9 after 3, 6, and 24 h of stimulating MDec with E. coli. Using immunofluorescence, it was confirmed the increase in the HFMi tissue and a reduction on the amount of type IV collagen leading to the separation of fetal amniochorion and MDEc. The degradative activity of proMMP-9 was reduced by 20% by coincubation with P4.ConclusionsP4 modulates the activity of proMMP-9 induced by E. coli stimulation but it was unable to completely reverse the degradation of type IV collagen in human MDec tissue.

Mechanism of pro-MMP9 activation in co-culture of pro-inflammatory macrophages and cardiomyocytes

ObjectiveA wide range of cardiac diseases is associated with inflammation. “Inflamed” heart tissue is infiltrated with pro-inflammatory macrophages which extensively secrete matrix metalloproteinase 9 (MMP9), a regulator of extracellular matrix turnover. As MMP9 is released from macrophages in a latent form, it requires activation. The present study addresses the role of cardiomyocytes in the course of this activation process. Methods and resultsIn mono- and co-cultures of pro-inflammatory rat macrophages (bone marrow-derived and peritoneal) and cardiomyocytes (H9C2 cell line) gelatin zymography demonstrated that activated macrophages robustly secreted latent pro-MMP9, whereas cardiomyocytes could not produce the enzyme. Co-culturing of the two cell species was critical for pro-MMP9 activation and was also accompanied by processing of cardiomyocyte-secreted pro-MMP2. A cascade of pro-MMP9 activation was initiated on macrophage membrane with pro-MMP2 cleavage. Namely, pro-inflammatory macrophages expressed an active membrane type 1 MMP (MT1MMP), which activated pro-MMP2, which in turn converted pro-MMP9. Downregulation of MT1MMP in macrophages by siRNA abolished activation of both pro-MMP2 and pro-MMP9 in co-culture. In addition, both cell species secreted MMP13 as a further pro-MMP9 activator. In co-culture, activation of pro-MMP13 occurred on membranes of macrophages and was enhanced in presence of active MMP2. Using incubations with recombinant MMPs and isolated macrophage membranes, we demonstrated that while both MMP2 and MMP13 individually had the ability to activate pro-MMP9, their combined action provided a synergistic effect. ConclusionActivation of pro-MMP9 in a co-culture of pro-inflammatory macrophages and cardiomyocytes was the result of a complex interaction of several MMPs on the cell membrane and in the extracellular space. Both cell types contributed critically to pro-MMP9 processing.

Discovery of novel indole derivatives as potent and selective inhibitors of proMMP-9 activation

Matrix metalloproteinase-9 (MMP-9) is a secreted zinc-dependent endopeptidase that degrades the extracellular matrix and basement membrane of neurons, and then contributes to synaptic plasticity by remodeling the extracellular matrix. Inhibition of MMP-9 activity has therapeutic potential for neurodegenerative diseases such as fragile X syndrome. This paper reports the molecular design, synthesis, and in vitro studies of novel indole derivatives as inhibitors of proMMP-9 activation. High-throughput screening (HTS) of our internal compound library and subsequent merging of hit compounds 1 and 2 provided compound 4 as a bona-fide lead. X-ray structure-based design and subsequent lead optimization led to the discovery of compound 33, a highly potent and selective inhibitor of proMMP-9 activation.

Tissue inhibitors of metalloproteinases are proteolytic targets of matrix metalloproteinase 9

Extracellular proteolysis and turnover are core processes of tissue homeostasis. The predominant matrix-degrading enzymes are members of the Matrix Metalloproteinase (MMP) family. MMPs extensively degrade core matrix components in addition to processing a range of other factors in the extracellular, plasma membrane, and intracellular compartments. The proteolytic activity of MMPs is modulated by the Tissue Inhibitors of Metalloproteinases (TIMPs), a family of four multi-functional matrisome proteins with extensively characterized MMP inhibitory functions. Thus, a well-regulated balance between MMP activity and TIMP levels has been described as critical for healthy tissue homeostasis, and this balance can be chronically disturbed in pathological processes. The relationship between MMPs and TIMPs is complex and lacks the constraints of a typical enzyme-inhibitor relationship due to secondary interactions between various MMPs (specifically gelatinases) and TIMP family members. We illustrate a new complexity in this system by describing how MMP9 can cleave members of the TIMP family when in molar excess. Proteolytic processing of TIMPs can generate functionally altered peptides with potentially novel attributes. We demonstrate here that all TIMPs are cleaved at their C-terminal tails by a molar excess of MMP9. This processing removes the N-glycosylation site for TIMP3 and prevents the TIMP2 interaction with latent proMMP2, a prerequisite for cell surface MMP14-mediated activation of proMMP2. TIMP2/4 are further cleaved producing ∼14 kDa N-terminal proteins linked to a smaller C-terminal domain through residual disulfide bridges. These cleaved TIMP2/4 complexes show perturbed MMP inhibitory activity, illustrating that MMP9 may bear a particularly prominent influence upon the TIMP:MMP balance in tissues.

Impact of Vitamin D3 on Carbonyl-Oxidative Stress and Matrix Metalloproteinases after Acute Intracerebral Hemorrhage in Rats with Type 2 Diabetes Mellitus.

Diabetes mellitus is associated with the development of carbonyl-oxidative stress (COS) and an increased risk of a cerebral hemorrhage. Vitamin D3 is considered an additional drug to have an impact on COS and proteolysis in the extracellular matrix. The study aimed to evaluate the impact of D3 on the COS-markers and matrix metalloproteinases MMP2/MMP9 activity after acute intracerebral hemorrhage (ICH) in rats with experimental type 2 diabetes mellitus (Т2DM) compared to metformin (Met). T2DM was induced in rats via the intraperitoneal injection of streptozotocin (STZ) and nicotinamide (NA), ICH - by microinjection of bacterial collagenase into the striatum. Rats were randomized into five groups: 1 - intact animals (n=8), 2 - T2DM (n=9); 3 - T2DM+ICH (n=7); 4 - T2DM+ICH+Met (n=7); 5 - T2DM+ICH+D3 (n=7). Blood glucose, glycated hemoglobin, and oral glucose tolerance test (OGTT) were assessed using commercial kits. Advanced oxidation protein products (AOPP), protein carbonyls (PC370/430), and ischemia-modified albumin (IMA) were measured by spectrophotometry, advanced glycation end products (AGEs) by quantitative fluorescence, and matrix metalloproteinases MMP2/9 by gelatin zymography. D3 does not significantly affect the glucose level and OGTT in rats with T2DM+ICH. However, it reduces AOPP, PC, and AGEs, thus reducing the COS index. In contrast, the activity of proMMP9 increases after D3 administration. These effects of D3 have been reported to be stronger and sometimes opposite to those of metformin. D3 supplementation may decrease the negative consequences of a cerebral hemorrhage in T2DM by reducing COS and preventing the accumulation of COS-modified proteins in the brain by regulating the expression and activity of MMP9.

Equine Placentitis in Mares Induces the Secretion of Pro-Inflammatory Cytokine eIL-1β and the Active Extracellular Matrix Metalloproteinase (MMP)-9.

Equine placentitis is characterized by infection and inflammation of the placenta. Different biomarkers associated with this inflammatory response have been evaluated in experimentally induced equine placentitis, but not in pregnant mares with spontaneous placentitis. The aim of the current study was to determine the concentration of eIL-1β and the activity of proMMP-2 and proMMP-9 in the serum of healthy mares and mares with placentitis on days 240 and 320 of gestation to explore whether these biomarkers are associated with equine maternal placentitis and/or with the birth of an infected or inviable foals. Serum samples were collected from sixteen pregnant English Thoroughbred mares, retrospectively classified as follows: (1) healthy mares with full-term gestation; and (2) mares with ultrasonographic signs of placentitis. The health of each foal was examined at birth, and it was decided to classify the cases into four groups: (1) healthy mares delivering a healthy foals (HM-HF, n = 6); (2) mares with USP delivering a healthy foal (USP-HF, n = 3); (3) mares with USP delivering a live septic foal (USP-LSeF, n = 4); and (4) mares with USP delivering a dead foal (USP-DF, n = 3). eIL-1β was quantified by ELISA, and proMMP-2 and proMMP-9 activity by gelatin zymography electrophoresis. In healthy mares, the serum concentrations of eIL-1β underwent a significant 16.5-fold increase from day 240 to day 320 of gestation. Although similar results were found in the mares with ultrasonographic signs of placentitis that delivered a healthy foal, those delivering a live septic or nonviable foal exhibited much higher concentrations of eIL-1β. proMMP-2 and proMMP-9 activity was not associated with maternal placentitis, foal infection, or death. Hence, the presence of placentitis severe enough to affect the health of the foal can be confirmed or discarded by determining the eIL-1β concentration in mares that have shown ultrasonographic signs of placentitis.

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

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

Differential proMMP-2 and proMMP-9 secretion in human pre-implantation embryos at day 5 of development.

Morphological development is the most common non-invasive criterion used to select in vitro human embryos for implantation. With this criterion, however, embryos in cellular arrest go unnoticed. A more accurate criterion is needed to improve the success rate of implantation. Extracellular matrix metalloproteases type 2 (MMP-2) and MMP-9 are key markers of embryonic development and the implantation process, according to various animal studies. The first objective of this study was to examine proMMP-2 and proMMP-9 activity in the culture media of human embryos with good morphological development. Secondly, the results of proMMP-2 and proMMP-9 activity in the culture medium were compared between pregnant and non-pregnant. Forty-two patients were approved by the Ethics and Research Committees of the Instituto Nacional de Perinatología in México City hospital, based on institutional inclusion criteria for in vitro fertilization. On day 5 of development, embryos were transferred to patients, and the culture media secretion profile of proMMP-2 and proMMP-9 activity was determined by substrate gel zymography. After analysis of embryo sac development, each patient was assigned to the pregnant (n=17) or non-pregnant (n=25) group. Our results demonstrate that proMMP-2 was active in the culture media corresponding to all 17 women achieving full-term pregnancy and proMMP-9 in the media corresponding to 11 of these women. Contrarily proMMP-2 and proMMP-9 were active in the culture media corresponding to 3 and 11 of the 25 non-pregnant patients, respectively. The clinical implications of this study suggest the activity evaluation of proMMP-2 and proMMP-9 in embryonic culture media on day 5 of development appears to be a reliable indicator of the quality of embryos and their capacity to establish a pregnancy.

The Catalytic Domain Mediates Homomultimerization of MT1-MMP and the Prodomain Interferes with MT1-MMP Oligomeric Complex Assembly.

Homomultimerization of MT1-MMP (membrane type 1 matrix metalloproteinase) through the hemopexin, transmembrane, and cytoplasmic domains plays a very important role in the activation of proMMP-2 and the degradation of pericellular collagen. MT1-MMP is overexpressed in many types of cancers, and it is considered to be a key enzyme in facilitating cancer cell migration. Since the oligomerization of MT1-MMP is important for its proteolytic activity in promoting cancer invasion, we have further investigated the multimerization by using heterologously expressed MT1-MMP ectodomains in insect cells to gain additional mechanistic insight into this process. We show that the whole ectodomain of MT1-MMP can form dimers and higher-order oligomeric complexes. The enzyme is secreted in its active form and the multimeric complex assembly is mediated by the catalytic domain. Blocking the prodomain removal determines the enzyme to adopt the monomeric structure, suggesting that the prodomain prevents the MT1-MMP oligomerization process. The binding affinity of MT1-MMP to type I collagen is dependent on the oligomeric state. Thus, the monomers have the weakest affinity, while the binding strength increases proportionally with the complexity of the multimers. Collectively, our experimental results indicate that the catalytic domain of MT1-MMP is necessary and sufficient to mediate the formation of multimeric structures.

Fetal DNA Causes Sex-Specific Inflammation From Human Fetal Membranes.

Inflammation is central to the mechanisms of parturition, but the lack of understanding of how it is controlled in normal parturition hampers our ability to understand how it may diverge resulting in preterm birth. Cell-free fetal DNA is found in the amniotic fluid, and it is thought to be able to activate inflammation as a danger-associated molecular pattern. Although its levels increases with gestational age, its effect has not been studied on the human fetal membranes. Thus, the aim of this study was to determine if the fetal DNA can trigger inflammation in the human fetal membranes and, thus, potentially contribute to the inflammatory load. Isolated human amniotic epithelial cells and fetal membrane explants were treated apically with fetal DNA causing the translocation of NF-KB into the nucleus of cells and throughout the cells of the explant layers with time. Fetal membrane explants were treated apically with either small or larger fragments of fetal DNA. IL-6, TNFα, and GM-CSF secretion was measured by ELISA, and pro-MMP2 and pro-MMP9 activity was measured by zymography from apical and basal media. Increased apical IL-6 secretion and basal pro-MMP2 activity was seen with small fragments of fetal DNA. When the data were disaggregated based on fetal sex, males had significant increases in IL-6 secretion and basal increased activity in pro-MMP2 and 9, whereas females had significantly increased basal secretion of TNFα. This was caused by the smaller fragments of fetal DNA, whereas the larger fragments did not cause any significant increases. Male fetal DNA had significantly lower percentages of methylation than females. Thus, when the cytokine and pro-MMP activity data were correlated with methylation percentage, IL-6 secretion significantly correlated negatively, whereas GM-CSF secretion positively correlated. These data support the role of fetal DNA as an inflammatory stimulus in the FM, as measured by increased NF-κB translocation, cytokine secretion, and increased pro-MMP activity. However, the data also suggested that the responses are different from FM tissues of male and female fetuses, and both the fragment size and methylation status of the fetal DNA can influence the magnitude and type of molecule secreted.

Developmental endothelial locus-1 protects from hypertension-induced cardiovascular remodeling via immunomodulation.

The causative role of inflammation in hypertension-related cardiovascular diseases is evident and calls for development of specific immunomodulatory therapies. We tested the therapeutic efficacy and mechanisms of action of developmental endothelial locus-1 (DEL-1), an endogenous antiinflammatory factor, in angiotensin II– (ANGII–) and deoxycorticosterone acetate–salt–induced (DOCA-salt–induced) cardiovascular organ damage and hypertension. By using mice with endothelial overexpression of DEL-1 (EC-Del1 mice) and performing preventive and interventional studies by injecting recombinant DEL-1 in mice, we showed that DEL-1 improved endothelial function and abrogated aortic adventitial fibrosis, medial thickening, and loss of elastin. DEL-1 also protected the mice from cardiac concentric hypertrophy and interstitial and perivascular coronary fibrosis and improved left ventricular function and myocardial coronary perfusion. DEL-1 prevented aortic stiffness and abolished the progression of hypertension. Mechanistically, DEL-1 acted by inhibiting αvβ3 integrin–dependent activation of pro-MMP2 in mice and in human isolated aorta. Moreover, DEL-1 stabilized αvβ3 integrin–dependent CD25+FoxP3+ Treg numbers and IL-10 levels, which were associated with decreased recruitment of inflammatory cells and reduced production of proinflammatory cytokines in cardiovascular organs. The demonstrated effects and immune-modulating mechanisms of DEL-1 in abrogation of cardiovascular remodeling and progression of hypertension identify DEL-1 as a potential therapeutic factor.

Structure-Activity Relationships of UTX-121 Derivatives for the Development of Novel Matrix Metalloproteinase-2/9 Inhibitors.

Celecoxib, a nonsteroidal anti-inflammatory drug, has been reported to have antitumor and antimetastatic activities, and it has potential for application in cancer treatments. The expression of matrix metalloproteinase (MMP)-2/9 is strongly correlated with cancer malignancy, and inhibition of these MMPs is believed to be effective in improving the antitumor and antimetastatic effects of drugs. We have previously revealed that UTX-121, which converted the sulfonamide of celecoxib to methyl ester, has more potent MMP-2/9 inhibitory activity than celecoxib. Based on these findings, we identified compounds with improved MMP inhibitory activity through a structure-activity relationship (SAR) study, using UTX-121 as a lead compound. Among them, compounds 9c and 10c, in which the methyl group of the p-tolyl group was substituted for Cl or F, showed significantly higher antitumor activity than UTX-121, and suppressed the expression of MMP-2/9 and activation of pro MMP-2. Our findings suggest that compounds 9c and 10c may be potent lead compounds for the development of more effective antitumor drugs targeting MMP.

TGF-β1 facilitates MT1-MMP-mediated proMMP-9 activation and invasion in oral squamous cell carcinoma cells

Matrix metalloproteinase (MMP)-2 and MMP-9, also known as gelatinases or type IV collagenases, are recognized as major contributors to the proteolytic degradation of extracellular matrix during tumor invasion. Latent MMP-2 (proMMP-2) is activated by membrane type 1 MMP (MT1-MMP) on the cell surface of tumor cells. We previously reported that cell-bound proMMP-9 is activated by the MT1-MMP/MMP-2 axis in HT1080 cells treated with concanavalin A in the presence of exogenous proMMP-2. However, the regulatory mechanism of proMMP-9 activation remains largely unknown. Transforming growth factor (TGF)-β1 is frequently overexpressed in tumor tissues and is associated with tumor aggressiveness and poor prognosis. In this study, we examined the role of TGF-β1 on MT1-MMP-mediated proMMP-9 activation using human oral squamous cell carcinoma cells. TGF-β1 significantly increased the expression of MMP-9. By adding exogenous proMMP-2, TGF-β1-induced proMMP-9 was activated during collagen gel culture, which was suppressed by the inhibition of TGF-β1 signaling or MT1-MMP activity. This MT1-MMP-mediated proMMP-9 activation was needed to facilitate TGF-β1-induced cell invasion into collagen gel. Thus, TGF-β1 may facilitate MT1-MMP-mediated MMP-9 activation and thereby stimulate invasion of tumor cells in collaboration with MT1-MMP and MMP-2.

Constituents of Aquilaria sinensis Leaves Upregulate the Expression of Matrix Metalloproteases 2 and 9.

In this novel study, we isolated 28 compounds from the leaves of Aquilaria sinensis (Lour.) Gilg based on a bioassay-guided procedure and also discovered the possible matrix metalloprotease 2 (MMP-2) and 9 (MMP-9) modulatory effect of pheophorbide A (PA). To evaluate the regulatory activity on MMP-2 and MMP-9, the HT-1080 human fibrosarcoma cells were treated with various concentrations of extracted materials and isolated compounds. PA was extracted by methanol from the leaves of A. sinensis and separated from the fraction of the partitioned ethyl acetate layer. PA is believed to be an active component for MMP expression since it exhibited significant stimulation on MMP-2 and proMMP-9 activity. When treating with 50 μM of PA, the expression of MMP-2 and MMP-9 were increased 1.9-fold and 2.3-fold, respectively. PA also exhibited no cytotoxicity against HT-1080 cells when the cell viability was monitored. Furthermore, no significant MMP activity was observed when five PA analogues were evaluated. This study is the first to demonstrate that C-17 of PA is the deciding factor in determining the bioactivity of the compound. The MMP-2 and proMMP-9 modulatory activity of PA indicate its potential applications for reducing scar formation and comparative medical purposes.

Sialic acid removal by trans-sialidase modulates MMP-2 activity during Trypanosoma cruzi infection

Matrix metalloproteinases (MMPs) not only play a relevant role in homeostatic processes but are also involved in several pathological mechanisms associated with infectious diseases. As their clinical relevance in Chagas disease has recently been highlighted, we studied the modulation of circulating MMPs by Trypanosoma cruzi infection. We found that virulent parasites from Discrete Typing Units (DTU) VI induced higher proMMP-2 and MMP-2 activity in blood, whereas both low (DTU I) and high virulence parasites induced a significant decrease in proMMP-9 plasma activity. Moreover, trans-sialidase, a relevant T. cruzi virulence factor, is involved in MMP-2 activity modulation both in vivo and in vitro. It removes α2,3-linked sialyl residues from cell surface glycoconjugates, which then triggers the PKC/MEK/ERK signaling pathway. Additionally, bacterial sialidases specific for this sialyl residue linkage displayed similar MMP modulation profiles and triggered the same signaling pathways. This novel pathogenic mechanism, dependent on sialic acid removal by the neuraminidase activity of trans-sialidase, can be exploited by different pathogens expressing sialidases with similar specificity. Thus, here we present a new pathogen strategy through the regulation of the MMP network.

Wound healing activity of the hydroethanolic extract of the leaves of Maytenus ilicifolia Mart. Ex Reis

Background and AimMaytenus ilicifolia has analgesic, healing, antioxidant and anti-inflammatory properties. This study evaluated effect of the hydroalcoholic extract of M. ilicifolia leaves on skin wound repair. Experimental procedureWounds were induced on mice and treated with the extract. The treatment was performed daily, until day 7 after wound induction. Wound closure was measured and the features of the repaired tissue were investigated, including mast cell quantification, neutrophil and macrophage activities, collagen deposition, angiogenesis, and pro-metalloproteases and metalloproteases 2 and 9 activity (pro-MMPs and MMPs). Results and conclusionThe M. ilicifolia extract accelerated the closure of wounds. The extract at a concentration of 4% was found to be effective, presenting anti-inflammatory effects and hemoglobin increased, along with increased soluble, total and type III collagens in the wound. In addition, there was an increase in pro-MMP9 and MMP9 activity after day 7th of treatment. The phenolic compounds and tannins present in this plant could be associated with the anti-inflammatory and healing activities observed in this study. Therefore, the ability to modulate essential parameters for accelerated and adequate healing as shown here suggests that the use of standardised extracts of M. ilicifolia and its fractions enriched in polyphenols may represent a therapeutic strategy for the treatment of wounds.

Resistance Training Modulates the Matrix Metalloproteinase-2 Activity in Different Trabecular Bones in Aged Rats.

BackgroundAging decreases osteogenic ability, inducing harmful effects on the bone extracellular matrix (ECM), while exercise training has been indicated as a tool to counteract bone disorders related to advancing age. The modulation of bone ECM is regulated by several types of matrix metalloproteinase (MMP); however, MMP-2 activity in different trabecular bones in response to resistance training (RT) has been neglected. Remodeling differs in different bones under the application of the same mechanical loading. Thus, we investigated the effects of 12 weeks of RT on MMP-2 activity in the lumbar vertebra (L6), tibia, and femur of young (3 months) and older rats (21 months).MethodsTwenty Wistar rats were divided into four groups (five animals per group): young sedentary or trained and older sedentary or trained. The 12-week RT consisted of climbing a 1.1-m vertical ladder three times per week with progressive weights secured to the animals’ tails. The animals were killed 48 h after the end of the experimental period. The MMP-2 activity was assessed by the zymography method.ResultsThe aging process induced lower MMP-2 activity in the lumbar vertebrae and tibia (p=0.01). RT upregulated pro, intermediate, and active MMP-2 activity in the tibia of young rats (p=0.001). RT also upregulated pro and active MMP-2 activity in the lumbar vertebrae and tibia with advancing age (p=0.01). There was no significant difference (p>0.05) between groups for MMP-2 of the femur, regardless of age and RT.ConclusionThe aging process impairs MMP-2 activity, but RT is a potential therapeutic approach to minimize the deleterious effects of ECM degeneration in different aged bones. Distinct MMP-2 responses to exercise training may result in specific remodeling processes.

Skin-healing properties of ginsenoside Rd against Ultraviolet-B-induced photooxidative stress through up-regulation of antioxidant components in HaCaT keratinocytes

Background: Korean ginseng (Panax ginseng Meyer) is a traditional herbal medicine used worldwide today. Ginsenoside Rd (Rd), one of its main ginsenosides, has been ascertained to have various pharmacological efficacies including neuroprotective and anti-inflammatory activities. Objectives: This work assesses the antioxidant and protective potentials of Rd against ultraviolet (UV)-B-induced skin photooxidative stress in HaCaT keratinocytes. Materials and Methods: Cell viability was detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Intracellular reactive oxygen species (ROS) were measured using dichlorodihydrofluorescein diacetate. Promatrix metalloproteinase-2 (proMMP-2) activity and protein were detected using gelatin zymography and western analysis. Total glutathione (GSH) content and total superoxide dismutase (SOD) activity were spectrophotometrically determined. Results: Rd, at varying concentrations non-toxic to HaCaT keratinocytes, attenuated the UV-B-induced ROS generation. Rd at 5, 12, and 30 μM attenuated the UV-B-induced proMMP-2 gelatinolytic activities to 59.3% ± 9.5%, 41.3% ± 9.5%, and 13.1% ± 8.9%, respectively, of those of the non-treated control cells. It could also diminish the UV-B-induced proMMP-2 protein levels. Rd at 5, 12, and 30 μM augmented the UV-B-reduced total SOD activities to 1.6 ± 0.2-, 2.4 ± 0.3-, and 3.2 ± 0.2-fold of those of the non-treated control cells, respectively. Rd could up-regulate the UV-B-reduced total GSH. Conclusion: Rd has counteracting properties against elevated ROS and proMMP-2 and attenuated GSH and SOD under UV-B irradiation, implying that it possesses a protective activity against photoaging possibly through up-regulating antioxidant components. These findings suggest that Rd can be considered as a novel natural resource for anti-photoaging functional cosmetics.

Change in Proteolytic Profile in Heifers After Oligofructose Overload.

Laminitis in cattle is an important underlying cause of lameness, which leads to a significant reduction in economic and animal welfare. Nevertheless, the disordered pathological processes of laminitis remain unclear. Several proteinases are probably involved in the disorder of basement membrane (BM) metabolism in laminitis, for instance, matrix metalloproteinases (MMPs), neutrophil elastase (NE), and myeloperoxidase (MPO). This study aimed to investigate the change in proteolytic profile in circulating and lamellar tissues using an oligofructose (OF) overload-induced laminitis model in heifers. Twelve clinically healthy and nonlame Chinese Holstein heifers were recruited and randomly divided into two groups: OF-induced and control (CON). The OF-induced heifers group (n = 6) was administered 17 g/kg of body weight (BW) of OF dissolved in 2 L/100 kg of BW of tap water via the oral-rumen tube. The CON group (n = 6) was given an equal volume of tap water. The plasma samples were collected 0, 6, 12, 18, 24, 36, 48, 60, and 72 h after administration, and the lamellar samples were collected 72 h after euthanasia. The plasma samples were analyzed by zymography and reverse zymography. Histological examination, zymography, reverse zymography, and Western blot of lamellar samples were conducted. In the plasma of the OF-induced group, the pro-MMP9 activity increased from 36 h (P < 0.001) to 60 h (P < 0.05). Moreover, the plasma tissue inhibitors of metalloproteinase 1 (TIMP1) activity decreased after 18 h (P < 0.05), while the ratio of pro-MMP9 to TIMP1 and TIMP2 increased after 18 h (P < 0.001) and 48 h (P < 0.05), respectively. The act-MMP2, pro-MMP9, and act-MMP9 activities increased in the lamellar tissue of the OF-induced group compared with the CON group (P < 0.05). In addition, the expression of lamellar NE protein was higher in the OF-induced group (P < 0.01), while no change was found in lamellar MPO protein compared with the CON group. In conclusion, increased pro-MMP9 combined with decreased TIMP1 activity in the circulation might have caused the activation of blood neutrophils, while the activation of proteolytic enzymes in lamellar tissue probably led to the dysfunction of BM in the OF-induced group.

Gelatinases Cleave Dentin Sialoprotein Intracellularly.

Dentin sialoprotein (DSP), the NH2-terminal fragment of dentin sialophosphoprotein (DSPP), is essential for dentin formation and further processed into small fragments inside the odontoblasts. Gelatinases, including matrix metalloproteinases 9 (MMP9) and MMP2, were able to cleave DSP(P) in tooth structures. We hypothesized that gelatinases may also cleave DSP intracellularly in the odontoblasts. In this study, the co-expression and physical interaction between DSP and gelatinases were proved by double immunofluorescence and in situ proximity ligation assay (PLA). Intracellular enzymatic activity of gelatinases was verified by gelatin zymography and in situ zymography. To confirm whether DSP was cleaved by active gelatinases intracellularly, lysates of wild-type (WT) odontoblastic cells treated with a MMP2 inhibitor or a MMP9 inhibitor or a MMP general inhibitor and of Mmp9–/– odontoblastic cells were analyzed by western blotting. Compared with the WT odontoblastic cells without inhibitor treatment, all these groups exhibited significantly higher ratios of high molecular weight to low molecular weight band density. FURIN was verified to be co-localized and physically interacted with MMP9 by double immunofluorescence and in situ PLA. The ratio of proMMP9 to activated MMP9 inside the odontoblastic cells were increased when function of endogenous FURIN was inhibited. And overexpressed proMMP9 was intracellularly cleaved by FURIN in the HEK293E cells, which was completely blocked by the mutation of proMMP9 with R96TPR99 substituted by A96AAA99. Taken together, these results indicate that DSP is intracellularly processed by gelatinases, and FURIN is involved in the intracellular activation of proMMP9 through cleavage of its R96TPR99 motif.