Effect of hormones on matrix metalloproteinases gene regulation in human aortic smooth muscle cells

Regenerative MRL/MpJ tendon cells exhibit sex differences in morphology, proliferation, mechanosensitivity, and cell-ECM organization

Clinical and animal studies have reported the influence of sex on the incidence and progression of tendinopathy, which results in disparate structural and biomechanical outcomes. However, there remains a paucity in our understanding of the sex-specific biological mechanisms underlying effective tendon healing. To overcome this hurdle, our group has investigated the impact of sex on tendon regeneration using the super-healer Murphy Roths Large (MRL/MpJ) mouse strain. We have previously shown that the scarless healing capacity of MRL/MpJ patellar tendons is associated with sexually dimorphic regulation of gene expression for pathways involved in fibrosis, cell migration, adhesion, and extracellular matrix (ECM) remodeling following an acute mid-substance injury. Thus, we hypothesized that MRL/MpJ scarless tendon healing is mediated by sex-specific and temporally distinct orchestration of cell-ECM interactions. Accordingly, the present study comparatively evaluated MRL/MpJ tendon cells on two-dimensional (2D; glass) and scaffold platforms to examine cell behavior under biochemical and topographical cues associated with tendon homeostasis and healing. Female MRL/MpJ cells showed reduced 2D migration and spreading area accompanied by enhanced mechanosensing, ECM alignment, and fibronectin-mediated cell proliferation compared to male MRL/MpJ cells. Interestingly, female MRL/MpJ cells cultured on isotropic scaffolds showed diminished cell-ECM organization compared to male MRL/MpJ cells. Lastly, MRL/MpJ cells elicited enhanced cytoskeletal elongation and alignment, ECM deposition and organization, and connexin 43-mediated intercellular communication compared to male B6 cells, regardless of culture condition or sex. These results provide insight into the cellular features conserved within the MRL/MpJ phenotype and potential sex-specific targets for the development of more equitable therapeutics.

The synergistic effects of testosterone and phophodiesterase-5 inhibitor combination on oxidative stress markers, matrix metalloproteinases and oxidative DNA damage: A randomized controlled experimental study

PURPOSE

To investigate the effects of combined tadalafil and testosterone usage on oxidative stress, DNA damage and MMPs in testosterone deficiency.

METHODS

Fifty rats were randomly divided into 5 groups (group-1: sham group-placebo, group-2: bilateral orchiectomy (ORX), group-3: bilateral ORX+tadalafil, group-4: bilateral ORX+testosterone, group-5: bilateral ORX+tadalafil+testosterone). Group-3 received tadalafil (5mg/kg/day, oral). Group-4 was administered testosterone undecanoate (100mg/kg i.m., single dose). Group-5 was administered a combination of tadalafil and testosterone undecanoate. All groups were compared with regard to serum nicotinamide adenine dinucleotide phosphate oxidase-4 (NOX-4), total thiol, matrix metalloproteinase-2 (MMP-2), MMP-3 and MMP-9, tissue inhibitor of metalloproteinases-1 (TIMP-1) and TIMP-2 and 8-hydroxy-2-deoxy guanosine (8-OHdG) levels.

RESULTS

Total thiol levels of group-2 were significantly lower than the other groups and thiol levels were higher in group-1 and group-5 than in the other groups. NOX4, MMP2 and 9 levels in group-2 were higher than in the other groups. MMP-9 levels in group-5 were lower than in groups 3 and 4 (p=.001). The level of 8-OHdG in groups 2 and 3 was higher than in the other groups (p=.001). In correlation analysis, 8-OHdG, MMP2, and 9 levels were negatively correlated with total thiol, whereas NOX4 and 8-OHdG levels were positively correlated with MMPs values.

CONCLUSIONS

The combination of testosterone with PDE-5 inhibitor suppresses MMP-9 levels and increases total thiol levels better than testosterone alone and tadalafil alone. Therefore, testosterone can be considered for use with PDE-5 inhibitor from the initial stage in case of testosterone deficiency.

Liposomal Nanocarriers Designed for Sub-Endothelial Matrix Targeting under Vascular Flow Conditions

Vascular interventions result in the disruption of the tunica intima and the exposure of sub-endothelial matrix proteins. Nanoparticles designed to bind to these exposed matrices could provide targeted drug delivery systems aimed at inhibiting dysfunctional vascular remodeling and improving intervention outcomes. Here, we present the progress in the development of targeted liposomal nanocarriers designed for preferential collagen IV binding under simulated static vascular flow conditions. PEGylated liposomes (PLPs), previously established as effective delivery systems in vascular cells types, served as non-targeting controls. Collagen-targeting liposomes (CT-PLPs) were formed by conjugating established collagen-binding peptides to modified lipid heads via click chemistry (CTL), and inserting them at varying mol% either at the time of PLP assembly or via micellar transfer. All groups included fluorescently labeled lipid species for imaging and quantification. Liposomes were exposed to collagen IV matrices statically or via hemodynamic flow, and binding was measured via fluorometric analyses. CT-PLPs formed with 5 mol% CTL at the time of assembly demonstrated the highest binding affinity to collagen IV under static conditions, while maintaining a nanoparticle characterization profile of ~50 nm size and a homogeneity polydispersity index (PDI) of ~0.2 favorable for clinical translation. When liposomes were exposed to collagen matrices within a pressurized flow system, empirically defined CT-PLPs demonstrated significant binding at shear stresses mimetic of physiological through pathological conditions in both the venous and arterial architectures. Furthermore, when human saphenous vein explants were perfused with liposomes within a closed bioreactor system, CT-PLPs demonstrated significant ex vivo binding to diseased vascular tissue. Ongoing studies aim to further develop CT-PLPs for controlled targeting in a rodent model of vascular injury. The CT-PLP nanocarriers established here show promise as the framework for a spatially controlled delivery platform for future application in targeted vascular therapeutics.

Expression of metalloproteinases MMP-2 and MMP-9 is associated to the presence of androgen receptor in epithelial ovarian tumors

BACKGROUND

The current study evaluated the metalloproteinases MMP-2 and MMP-9 expression in epithelial cells and the surrounding stroma in ovarian tumors and the association of MMPs with the histological subtypes, the clinical stage and the presence of steroid hormone receptors. Tumor samples were obtained from 88 patients undergoing surgical cytoreduction of primary ovarian tumors in Instituto Nacional de Cancerología, from México City. The formalin fixed and paraffin embedded samples were processed in order to demonstrate the presence of androgen receptor,estrogen receptor alpha, progesterone receptor, MMP-2,MMP-9 and collagen IV by immunohistochemistry and/or immunofluorescence.

RESULTS

MMP-2 and MMP-9 were differentially expressed in the epithelium and the stroma of ovarian tumors associated to histological subtype, clinical stage and sexual steroid hormone receptor expression. Based on Cox proportional hazard regression model we demonstrated that MMP-2 located in the epithelium and the stroma are independent prognostic biomarkers for overall survival in epithelial ovarian tumors. Kaplan Meir analysis of the combination of AR (+) with MMP-2 (+) in epithelium and AR (+) with MMP-2 (-) in stroma displayed a significant reduction of survival.

CONCLUSIONS

The presence of MMP-2 in the stroma of the tumor was a protective factor while the presence of MMP-2 in the epithelium indicated an adverse prognosis. The presence of AR associated with MMP-2 in the tumor cells was a risk factor for overall survival in epithelial ovarian cancer.

Dietary supplementation with Zyflamend poly-herbal extracts and fish oil inhibits intimal hyperplasia development following vascular intervention

The polyherbal blend Zyflamend™ has been shown to have anti-inflammatory properties and attenuate inflammatory-modulated pathologies. Fish oils have also been shown to have cardioprotective properties. However, the beneficial effects of their combination have not been investigated. Intimal hyperplasia (IH), a pathological remodeling response of a vessel to injury, is heavily regulated by an immune-mediated reaction. The objective of this study was to determine if dietary supplementation with Zyflamend and/or Wholemega could affect inflammatory-dependent vascular remodeling mechanisms when provided at human equivalent doses. Based on their anti-inflammatory properties and protective benefits demonstrated in previous pre-clinical studies, we hypothesized administration of these supplements would prevent IH in an animal model of vascular injury. The diets of aged male rats were supplemented with human equivalent doses of Zyflamend (Zyf) and/or Wholemega (WMega) or placebo (Plac) for 1wk prior to balloon angioplasty (BA)-induced injury of the left carotid artery. At 28d post-injury morphometric analysis of carotid tissue revealed IH was decreased in Zyf + WMega animals compared to placebo, while Zyf or WMega independently had no significant effect. Serum cytokine screening indicated injury-induced interleukin family isoforms, interferon-γ, and macrophage inflammatory proteins were downregulated by Zyf + WMega. Immunohistochemical staining for monocyte/macrophage phenotypic markers revealed that while overall monocyte/macrophage vessel infiltration was not affected, Zyf + WMega limited the alternative differentiation of M2 macrophages and reduced the presence of myofibroblasts in the injured vessel wall. In summary, dietary supplementation with Zyf + WMega attenuated the acute inflammatory response following vascular injury and inhibited IH development in vivo.

Improving the efficacy of liposome-mediated vascular gene therapy via lipid surface modifications

BACKGROUND

We have previously defined mechanisms of intimal hyperplasia that could be targets for molecular therapeutics aimed at vascular pathology. However, biocompatible nanocarriers are needed for effective delivery. Cationic liposomes (CLPs) have been demonstrated as effective nanocarriers in vitro. However, in vivo success has been hampered by cytotoxicity. Recently, neutral PEGylated liposomes (PLPs) have been modified with cell-penetrating peptides (CPPs) to enhance cellular uptake. We aim to establish CPP-modified neutral liposomes as viable molecular nanocarriers in vascular smooth muscle cells.

METHODS

CLPs, PLPs, and CPP-modified PLPs (R8-PLPs) were assembled with short interfering RNA (siRNA) via ethanol injection. Characterization studies determined liposomal morphology, size, and charge. siRNA encapsulation efficiency was measured via RiboGreen assay. Vascular smooth muscle cells were exposed to equal lipid/siRNA across all groups. Rhodamine-labeled liposomes were used to quantify cell association via fluorometry, live/dead dual stain was used to measure cytotoxicity, and gene silencing was measured by quantitative polymerase chain reaction.

RESULTS

R8-PLPs exhibited increased encapsulation efficiency equivalent to CLPs. PLPs and R8-PLP-5 mol% and R8-PLP-10 mol% had no cytotoxic effect. CLPs demonstrated significant cytotoxicity. R8-PLP-5 mol% and R8-PLP-10 mol% exhibited increased cell association versus PLPs. R8-PLP-10 mol% resulted in significant gene silencing, in a manner dependent on lipid-to-siRNA load capacity.

CONCLUSIONS

The negligible cytotoxicity and enhanced cellular association and gene silencing capacity exhibited by R8-PLPs reveal this class of liposomes as a candidate for future applications. Further modifications for optimizing R8-PLPs are still warranted to improve efficacy, and in vivo studies are needed for translational development. However, this could prove to be an optimal nanocarrier for vascular gene therapeutics.

Testosterone replacement attenuates intimal hyperplasia development in an androgen deficient model of vascular injury

BACKGROUND

Androgen deficiency (AD) is associated with increased risk of vascular disease. Dysfunctional remodeling of the vessel wall and atypical proliferative potential of vascular smooth muscle cells (VSMCs) are fundamental processes in the development of intimal hyperplasia (IH). We have demonstrated an inverse relationship between dihydrotestosterone (DHT) levels, matrix metalloproteinase activity, and VSMC migration and proliferation in vitro. Here, we investigated the role of AD and testosterone (TST) replacement in IH development in an animal model of vascular injury to elucidate mechanisms modulated by AD that could be playing a role in the development of vascular pathogenesis.

METHODS

Aged orchiectomized male rats underwent TST supplementation via controlled release pellet (0.5-35 mg). Young adult and middle-age adult intact (MI) and orchiectomized placebo (Plac) groups served as controls. All groups underwent balloon angioplasty of the left common carotid at a 14-d post-TST. Carotid tissue was collected at a 14-d post-balloon angioplasty and subjected to morphologic and immunohistochemical analyses. Human male VSMCs were treated with DHT (0-3000 nM) for 24 h then subjected to quantitative PCR for gene expression analyses and costained for F-actin and G-actin for visualization of cytoskeletal organization.

RESULTS

I:M ratio was increased in Plac, subphysiological, low-physiological, and high pharmacologic level TST animals compared with MI controls but was decreased with high-physiological TST supplementation. Injury-induced expression of previously defined matrix metalloproteinase remodeling enzymes was not significantly affected by TST status. Urotensin (UTS) receptor (UTSR) staining was low in injured vessels of all young adult intact, MI, and Plac controls but was significantly upregulated in all groups receiving exogenous TST supplementation, irrespective of dose. In vitro DHT exposure increased the expression of UTSR in VSMCs in a dose-dependent manner. However, this did not correlate with any change in proliferative markers. F:G actin staining revealed that DHT-induced cytoskeletal organization in a dose-dependent manner.

CONCLUSIONS

AD increased IH development in response to vascular injury, whereas physiological TST replacement attenuated this effect. AD-induced IH occurs independent of matrix remodeling mechanisms known to be heavily involved in vascular dysfunction, and AD alone does not affect the UTS and/or UTSR mechanism. Exogenous TST and/or DHT increases UTSR pathway signaling in vitro and in vivo. This modulation correlates to a shift in cytoskeletal organization and may exacerbate vasoconstrictive pathogenesis. While physiological TST replacement attenuates AD-modulated IH development, its UTS-mediated effect on vasotone may prove deleterious to overall vascular function.

Comparative analysis of polymers for short interfering RNA delivery in vascular smooth muscle cells

The use of short interfering RNA (siRNA) to degrade messenger RNA in the cell cytoplasm and transiently attenuate intracellular proteins shows promise in the inhibition of vascular pathogenesis. However, a critical obstacle for therapeutic application is a safe and effective delivery system. Biodegradable polymers are promising alternative molecular carriers for genetic material. Here, we aim to perform a comparative analysis of poly(B-amino ester) (PBAE) and polyethylenimine (PEI) polymers in their efficacy for vascular smooth muscle cell transfection using siRNA against the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) housekeeping gene as our test target.

METHODS

Human aortic smooth muscle cells (HASMC) were transfected in vitro with polymers conjugated to GAPDH or negative control (NC) siRNAs. Increasing siRNA:polymer ratios were tested for optimal transfection efficiency. DharmaFECT2 chemical transfection complexes were used for comparative analysis. Live/dead dual stain was used to measure cell viability, and GAPDH gene silencing was measured by quantitative polymerase chain reaction normalized to 18S.

RESULTS

The highest rate of PEI-mediated silencing was achieved with a 9μL polymer:220 pmol/mL siRNA conjugate (16 ± 2% expression versus NC; n = 6). Comparable PBAE-mediated silencing could be achieved with a 1.95μL polymer:100 pmol/mL siRNA conjugate (10 ± 1% expression versus NC; n = 5). Transfection using PEIs resulted in silencing equivalent to other methods but with less efficiency and increased cell toxicity at 24h polymer exposure. Decreasing PEI exposure time to 4 h resulted in similar silencing efficacy (21 ± 9% expression versus NC, n = 6) with an improved toxicity profile.

CONCLUSIONS

Polymeric bioconjugates transfected HASMCs in a manner similar to chemical complexes, with comparable cell toxicity and silencing efficiency. PEI bioconjugates demonstrated silencing equivalent to PBAE bioconjugates, although less efficient in terms of required polymer concentrations. Given the cost-to-benefit difference between the assayed polymers, and PEI's ability to transfect HASMCs within a short duration of exposure with an improved toxicity profile, this study shows that PEI bioconjugates are a potential transfection agent for vascular tissue. Future studies will expand on this method of gene therapy to validate delivery of gene-specific inhibitors aimed at attenuating smooth muscle cell proliferation, adhesion, and migration. These studies will lay the framework for our future experimental plans to expand on this method of gene therapy for in vivo transfection in animal models of vascular disease.

Mixtures of environmentally relevant endocrine disrupting chemicals affect mammary gland development in female and male rats

Estrogenic chemicals are able to alter mammary gland development in female rodents, but little is known on the effects of anti-androgens and mixtures of endocrine disrupting chemicals (EDCs) with dissimilar modes of action. Pregnant rat dams were exposed during gestation and lactation to mixtures of environmentally relevant EDCs with estrogenic, anti-androgenic or dissimilar modes of action (TotalMix) of 100-, 200- or 450-fold high end human intake estimates. Mammary glands of prepubertal and adult female and male offspring were examined. Oestrogens increased mammary outgrowth in prepubertal females and the mRNA level of matrix metalloproteinase-3, which may be a potential biomarker for increased outgrowth. Mixtures of EDCs gave rise to ductal hyperplasia in adult males. Adult female mammary glands of the TotalMix group showed morphological changes possibly reflecting increased prolactin levels. In conclusion both estrogenic and anti-androgenic chemicals given during foetal life and lactation affected mammary glands in the offspring.

Low testosterone elevates interleukin family cytokines in a rodent model: a possible mechanism for the potentiation of vascular disease in androgen-deficient males

BACKGROUND

Androgen deficiency (AD) is associated with increased risk of atherosclerosis, cardiovascular, and peripheral arterial disease. Although the biochemical and molecular mechanisms underlying this risk remain unclear, higher testosterone (TST) levels correlate to significant immunoprotective molecular and cellular responses. Our group has previously demonstrated that female sex hormones influence vascular pathogenesis via inflammatory-modulated matrix metalloproteinase (MMP) regulation. Here we investigated the role of AD and androgen replacement therapy in the modulation of these hormonally responsive pathways that could be playing a role in the development of vascular pathogenesis.

METHODS

Aged orchiectomized male rats underwent TST supplementation per controlled release pellet implantation (0-150 mg). Young and aged intact groups served as controls. Serum was collected at 0-4 wk and analyzed by enzyme-linked immunosorbent assays, qualitative cytokine screening, and quantitative multiplex analyses. Human aortic smooth muscle cells were treated with 4,5α-dihydrotestosterone (DHT; 0-3000 nM) before or after interleukin 1β (IL-1β; 5 ng/mL) stimulation. Quantitative polymerase chain reaction and in-gel zymography was used to assay the effect on MMP expression and activity.

RESULTS

Subphysiological, physiological, and supraphysiological levels of TST were achieved with 0.5, 2.5, and 35 mg TST pellet implants in vivo, respectively. Inflammatory arrays indicated that interleukin cytokines, specifically IL-2, IL-6, IL-10, IL-12, and IL-13, were elevated at subphysiological level of TST, whereas TST supplementation decreased interleukins. Supraphysiological TST resulted in a significant increase in MMP-9 and tissue inhibitor of metalloproteinase-1 (TIMP-1) in vivo. Pretreatment with IL-1β slightly increased membrane type 1-MMP (MT1-MMP) and MMP-2 expression at low to mid-level DHT exposure in vitro, although these trends were not statistically significant.

CONCLUSIONS

Here we demonstrate AD is a proinflammatory modulator and indicate that MMP-independent mechanisms may play a role downstream of AD-induced inflammatory signaling in dysfunctional vascular remodeling. Future in vivo studies will examine AD and TST supplementation in acute inflammatory response to vascular injury and in MMP-modulated vascular disease.

Association of the polymorphisms of MMP-9 and TIMP-3 genes with thoracic aortic dissection in Chinese Han population

AIM

Thoracic aortic dissection (TAD) is the most common life-threatening disorder, and a shifted balance of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) is involved in TAD pathogenesis. The aim of this study was to evaluate the association of 4 single-nucleotide polymorphisms (SNPs) in MMP-9 and TIMP-3 genes with TAD risk in Chinese Han population.

METHODS

A total of 206 Chinese patients with TAD and 180 controls were included in this study. Four SNPs (rs3918249, rs2274756, rs9609643 and rs8136803) were genotyped using high-throughput MALDI-TOF mass spectrometry. Allele and genotype association analyses were conducted using PLINK.

RESULTS

All the 4 SNPs resulted in Hardy-Weinberg equilibrium in patients and controls. The G allele frequency for the MMP-9 SNP rs2274756 was significantly higher in female TAD patients than in female controls (P=0.0099). Moreover, after adjusting for traditional cardiovascular risk factors (sex, age, hypertension, dyslipidemia, diabetes and smoking habit), the rs2274756 polymorphism (odds ratio: 0.30; 95% confidence interval: 0.11 to 0.79, P=0.015) resulted in an independent susceptibility factor for TAD in females. No associations were found between the other SNPs and TAD.

CONCLUSION

The results provide strong evidence for an association between MMP-9 SNP rs2274756 and female TAD risk in Chinese Han population.

Effect of hormone replacement therapy in matrix metalloproteinase expression and intimal hyperplasia development after vascular injury

BACKGROUND

Postmenopausal women taking hormone replacement therapy (HRT) require secondary intervention after vascular reconstruction more frequently than women not taking HRT, often due to increased development of intimal hyperplasia (IH). Matrix metalloproteinases (MMPs) play a role in IH by degradation and remodeling of components of the vascular basement membrane. The MMP pathway is regulated by a balance between MMPs, membrane-type MMPs (MT-MMPs), and tissue inhibitor of MMPs (TIMPs). We have recently provided evidence for unbalanced regulation of the MT1-MMP/MMP-2 pathway in vascular smooth muscle cells (VSMCs) exposed to hormones in vitro. Herein we study the role of HRT in the development of IH in a postmenopausal rodent model of vascular injury and in the modulation of this MMP regulatory pathway in vivo.

METHODS

Female rats were aged to 12 months. Animals were ovariectomized (OVX) and 4 weeks later hormones or placebo was delivered via a 90-day slow-release pellet. After 6 weeks of HRT each rat underwent balloon angioplasty of the left common carotid artery. At 14 days postinjury tissue samples were collected and stained with trichrome elastin and for isoform-specific MMPs.

RESULTS

After vascular injury, the intima:media (I:M) ratio was decreased in OVX rats receiving placebos as compared with non-OVX controls (P < 0.05). In OVX animals receiving HRT, estrogen with and without progesterone and progesterone alone slightly increased I:M ratio compared with placebo, although no significant difference was found in any HRT group. Injury-induced intimal expression of MMP-2 and -9 was decreased in OVX placebo animals compared with non-OVX controls (P < 0.05). MMP-2 and -9 levels were subsequently increased by each type of hormone therapy compared with placebo, with a significant increase in MMP-9 in response to estrogen with and without progesterone (P < 0.05). Conversely, TIMP-2 was decreased by estrogen compared with placebo (P < 0.05). There was no effect on intimal MT1-MMP in any group.

CONCLUSIONS

In this study we detected a statistically significant decrease in IH as a result of OVX. Subsequent HRT exposure resulted in increased I:M ratios compared with OVX animals given placebo, although significance was not reached with the doses given. Long-term exogenous exposure may have a more deleterious effect compared with acute exposure and should be examined further. We also demonstrated a significant reduction in MMP-2 and -9 and TIMP-2 in response to OVX. Subsequent hormone exposure resulted in the upregulation of MMP-2 and -9 without a counterregulatory increase in TIMP, indicating that HRT modulates the MMP regulatory pathway in vivo. The data suggest that the lack of hormones after OVX protects against pathologic remodeling in our aged model of disease and that exposure to both natural and exogenous hormones could be a negative risk factor resulting in an exaggerated vascular response to injury. Future studies should focus on in vivo manipulation of unbalanced MMP regulation for prevention of IH in response to HRT and in general. Furthermore, the age-associated difference in response to the presence of natural hormones in young vs aged models should be investigated.

Effects of diosgenin on myometrial matrix metalloproteinase-2 and -9 activity and expression in ovariectomized rats

Diosgenin, a traditional Yam extraction, has been used in hormone replacement for menopausal women. We aimed to investigate the influences of diosgenin administration upon the MMP-2 and -9 activity and expression and reproductive hormones of ovariectomized (OVX) rats, a model of menopausal status. Seven-week old female Wistar rats with bilateral OVX or sham operation (controls) were divided and administered different dosages of diosgenin (0, 10, 50, or 100 mg/kg/day) for 8 weeks. Serum was then sampled for progesterone (P4) and estradiol (E2) assay and uterine horns harvested. Myometrial MMP-2 and -9 activity and expression were surveyed and myometrial collagen expression was also assayed. The results show higher body weight in OVX rats across the 8 weeks post surgery and no significant differences were noted among OVX or Sham rats with diosgenin supplements. There were lower P4 and E2 concentrations in OVX rats compared to Sham rats, and higher P4 concentration of Sham rats post diosgenin supplement. MMP-2 and -9 mRNA expression and activity was lower in OVX rats, although higher MMP-2 and lower MMP-9 activity/mRNA expression was observed in OVX rats post diosgenin supplementation. Collagen mRNA expression was higher in OVX rats compared to Sham controls, and diosgenin administration decreased collagen mRNA expression in OVX rats. In conclusion, diosgenin is associated with gelatinase expression and collagen metabolism in OVX rats. Diosgenin administration can partially reverse the effects of OVX upon MMP functions and hormone status. Adequate diosgenin supplement might modulate myometrial gelatinase expression and collagen metabolism in menopausal subjects.

Role of MT1-MMP in estrogen-mediated cellular processes of intimal hyperplasia

BACKGROUND

Hormone replacement therapy increases intimal hyperplasia (IH) following vascular intervention. Matrix metalloproteinases (MMPs) play a role in IH development. We have shown estrogen up-regulates MT1-MMP expression, a transmembrane protein that activates MMP-2, and increases vascular smooth muscle cell (VSMC) collagen invasion via increased MMP-2 activity. Here we hypothesize inhibition of MT1-MMP will prevent hormonally-stimulated increased MMP-2 activation and the downstream cellular processes of IH pathogenesis.

METHODS

VSMCs from a postmenopausal donor were transfected with MT1-MMP or negative control siRNAs, treated with estrogen (Est), analyzed by q-PCR, Western blot, zymography, migration, invasion, and proliferation assays.

RESULTS

Est treatment of MT1-MMP silenced cells still resulted in increased MT1-MMP expression (C = 41% ± 4%; Est = 52% ± 2%; P < 0.05). Silencing of MT1-MMP decreased basal MMP-2 activity (nonsilenced = 100%; MT1-silenced = 87% ± 3%; P < 0.05) but had no effect on basal invasion or proliferation. Est treatment of MT1-MMP silenced cells still resulted in increased MMP-2 activity (C = 87% ± 3%; Est = 101% ± 4%; P < 0.05) and invasion (C = 89% ± 6%; Est = 109% ± 3%; P < 0.05) compared with MT1-MMP silenced control cells. However, silencing of MT1-MMP did inhibit Est- and serum-stimulated proliferation (C = 106% ± 18%; Est = 104% ± 16%; FBS = 121% ± 24%; P = NS).

CONCLUSION

Silencing of MT1-MMP in aged VSMCs results in impaired but not complete inhibition of basal and Est-stimulated increases in MMP-2 activity. Other mechanisms appear to be playing a role in hormonally-regulated cellular processes of IH pathogenesis. Future studies will target other signaling cascades, with the goal of identifying mechanisms responsible for hormonally-modulated unbalanced MMPs. In vivo manipulation of the expression patterns of MT1-MMP will be examined for the prevention of IH in animal models of vascular disease.

Heterogeneity in MT1-MMP activity with ischemia-reperfusion and previous myocardial infarction: relation to regional myocardial function

After a myocardial infarction (MI), an episode of ischemia-reperfusion (I/R) can result in a greater impairment of left ventricular (LV) regional function (LVRF) than that caused by an initial I/R episode in the absence of MI. Membrane type-I matrix metalloproteinase (MT1-MMP) proteolytically processes the myocardial matrix and is upregulated in LV failure. This study tested the central hypothesis that a differential induction of MT1-MMP occurs and is related to LVRF after I/R in the context of a previous MI. Pigs with a previous MI [3 wk postligation of the left circumflex artery (LCx)] or no MI were randomized to undergo I/R [60-min/120-min left anterior descending coronary artery (LAD) occlusion] or no I/R as follows: no MI and no I/R (n = 6), no MI and I/R (n = 8), MI and no I/R (n = 8), and MI and I/R (n = 8). Baseline LVRF (regional stroke work, sonomicrometry) was lower in the LAD region in the MI group compared with no MI (103 ± 12 vs. 188 ± 26 mmHg·mm, P < 0.05) and remained lower with peak ischemia (35 ± 8 vs. 88 ± 17 mmHg·mm, P < 0.05). Using a novel interstitial microdialysis method, MT1-MMP was directly measured and was over threefold higher in the LCx region and over twofold higher in the LAD region in the MI group compared with the no MI group at baseline. MT1-MMP fluorogenic activity was persistently elevated in the LCx region in the MI and I/R group but remained unchanged in the LAD region. In contrast, no changes in MT1-MMP occurred in the LCx region in the no MI and I/R group but increased in the LAD region. MT1-MMP mRNA was increased by over threefold in the MI region in the MI and I/R group. In conclusion, these findings demonstrate that a heterogeneous response in MT1-MMP activity likely contributes to regional dysfunction with I/R and that a subsequent episode of I/R activates a proteolytic cascade within the MI region that may contribute to a continued adverse remodeling process.

Estrogen improves TIMP-MMP balance and collagen distribution in volume-overloaded hearts of ovariectomized females

Our previous studies demonstrate that 17beta-estradiol limits chronic volume overload-induced hypertrophy and improves heart function in ovariectomized rats. One possible cardioprotective mechanism involves the interaction between estrogen, estrogen receptors, and proteins of the extracellular matrix (ECM). The impact of estrogen deficiency and replacement on left ventricular (LV) hypertrophy and ECM protein expression was studied using five female rat groups: intact sham-operated, ovariectomized sham-operated, intact with volume overload, ovariectomized with volume overload, and ovariectomized with volume overload treated with estrogen. After 8 wk, LV protein extracts were evaluated by Western blot analysis for matrix metalloproteinase-2 (MMP-2) and MMP-9, MT1-MMP, tissue inhibitors of MMPs (TIMP)-1, TIMP-2, TIMP-3 and TIMP-4, collagens type I and III, and estrogen receptor alpha and beta expression. MMP proteolytic activity was assessed by zymography. All volume-overloaded groups exhibited LV hypertrophy, which was associated with a loss of interstitial collagen and perivascular fibrosis. After 8 wk of volume overload, 70% of ovariectomized rats developed heart failure, in contrast to only one intact rat. A downregulation of MMP-2, estrogen receptor-alpha (ERalpha), and ERbeta, and upregulation of MMP-9 and MT1-MMP were found in the volume-overloaded hearts of ovariectomized rats. Estrogen treatment improved TIMP-2/MMP-2 and TIMP-1/MMP-9 protein balance, restored ERalpha expression, and prevented MMP-9 activation, perivascular collagen accumulation and development of heart failure. However, estrogen did not fully restore ERbeta expression and did not prevent the increase of MMP-9 expression or loss of interstitial collagen. These results support that estrogen limits undesirable ECM remodeling and LV dilation, in part, through modulation of ECM protein expression in volume-overloaded hearts of ovariectomized rats.

Are proteinases the reason for keratoconus?

PURPOSE

Keratoconus is a degenerating disease of the eye that results in an irregularly-shaped cornea. The etiology of the disease is unknown and the prognosis is difficult due to the variability in outcome. Keratoconus has been associated with eye rubbing, atopy, contact lens wear, as well as genetic conditions, such as Down's syndrome, Ehlers-Danlos syndrome, and Marfan's syndrome. Thinning of the cornea in keratoconus has been well studied and is documented to occur as a result of degradation of corneal collagen. The reason for this tissue degradation is unknown but has been hypothesized to be linked with proteases.

METHODS

This study used a literature search to review the role of proteases and inflammatory molecules in the aetiology of keratoconus.

RESULTS

Early studies demonstrated elevated levels of collagenolytic and gelatinolytic activities in laboratory cultures of keratoconic corneas. Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteins that include collagenases and gelatinases. MMPs levels are altered in keratoconus corneas compared to normal corneas and the level of tissue inhibitor of metalloproteinases-1 (TIMP-1) is decreased in keratoconic corneas. Recent studies have demonstrated the involvement of Cathepsin B, G, and K in keratoconus. Although thought to be a non-inflammatory disease, inflammatory molecules, such as interleukins and tumor necrosis factor have been shown to be elevated in keratoconus, and these inflammatory molecules may mediate production and activation of proteases.

CONCLUSIONS

Proteases may be implicated in keratoconus. An in-depth investigation of these proteases may help in better understanding the course of the disease.

The inhibitory effect of 15-R-LXA4 on experimental endometriosis

OBJECTIVE

To determine the pro-resolution actions of 15-R-LXA(4) (LXA(4)) on endometriotic lesions and on the expression of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in the murine endometriosis model.

STUDY DESIGN

In a prospective, placebo-controlled experimental study, endometriosis was induced in thirty BALB/c mice, and fifteen sham-operated mice served as negative controls. Among the thirty mice with induced endometriosis, fifteen were administered 15-R-LXA(4) and acted as study group (LXA(4) group) and the other fifteen were used as positive controls (EM group). Then all the mice were sacrificed and the endometriotic lesions were weighed. The mRNA and protein levels of IL-1beta and TNF-alpha in the peritoneal fluid were quantified by using real-time polymerase chain reaction (PCR) and enzyme-linked immunoabsorbent assay (ELISA).

RESULT(S)

Compared with the positive controls, 15-R-LXA(4) reduced the weight of the endometriotic lesions, decreased the concentrations of IL-1beta and TNF-alpha, and lowered the mRNA levels of IL-1beta and TNF-alpha in peritoneal fluid cells.

CONCLUSION(S)

These findings suggest that 15-R-LXA(4) inhibits the progression of endometriosis possibly by suppressing the gene and protein expression of IL-1beta and TNF-alpha.

Serum levels of matrix metalloproteinase-2 as a marker of intimal hyperplasia

BACKGROUND

A primary component in the development of intimal hyperplasia (IH) in response to vascular injury is basement membrane remodeling. Matrix metalloproteinases (MMPs) play a major role in this process by degradation of basement membrane proteins, mainly collagen type IV. Vascular injury initiates an inflammatory cascade with the release of tumor necrosis factor-alpha (TNFalpha), interleukin-1beta (IL-1beta), and C-reactive protein (CRP). We hypothesize serum levels of these elements may serve as biomarkers of the development of IH.

METHODS AND RESULTS

At baseline, 2, 7, 10, and 14 days post-balloon angioplasty of the carotid artery, rat tissue samples were stained with Masson trichrome elastin to examine IH. Intima:media ratios (I:M) increased significantly over time postinjury. Serum samples were collected at the time of tissue sampling, and levels of MMP-2, MMP-9, collagen type IV, TNFalpha, IL-1beta, and CRP were assayed using sandwich enzyme-linked immunosorbent assay (ELISA). MMP-2 serum levels at 7, 10, and 14 days postinjury were significantly elevated compared with baseline. Other elements were not significantly elevated.

CONCLUSION

Early and persistent elevation in the serum levels of MMP-2 may be a useful biomarker of basement membrane remodeling and the presence of IH.

Regulation of vascular smooth muscle cell expression and function of matrix metalloproteinases is mediated by estrogen and progesterone exposure

OBJECTIVE

Postmenopausal women receiving hormone replacement therapy (HRT) have been reported to have more adverse outcomes after vascular reconstructions, including increased intimal hyperplasia development and bypass graft failure. HRT may be affecting the pathway contributing to intimal hyperplasia. An important component of this pathway involves matrix metalloproteinases (MMPs), implicated in vascular remodeling due to their ability to degrade components of the extracellular matrix. We hypothesize that estrogen (Est) and progesterone (Prog) upregulate the MMP pathway in vascular smooth muscle cells (VSMCs) thereby increasing MMP activity and function.

METHODS AND RESULTS

VSMCs were incubated with Est (5 ng/mL), Prog (50 ng/mL), Est + Prog combination (Est/Prog), and/or doxycycline (40 microg/mL; Doxy). Using reverse transcriptase polymerase chain reaction (RT-PCR) analysis we have previously shown membrane type 1-MMP (MT1-MMP) messenger ribonucleic acid (mRNA) levels are significantly increased by Est. Here, Western blot analyses indicated MT1-MMP and MMP-2 protein levels, not tissue inhibitor of MMP-2 (TIMP-2), were increased in response to Est and Est/Prog (P < .05 vs control). In-gel zymography revealed that Est and Est/Prog resulted in increased MMP-2 activity (hormone groups, P < .05 vs control) with no significant difference among the hormone groups. VSMC migration was increased by 45 +/- 14% in response to Est (P < .05 vs control), as measured using a modified Boyden chamber assay. Doxycycline significantly inhibited basal and Est/Prog-stimulated increases in MMP-2 activity (P < .05 vs control; P < .05 vs hormone groups), and partially blocked basal and hormonally stimulated migration (P < .05 vs control and Est).

CONCLUSION

Estrogen and progesterone affects the MMP pathway by increasing MMP-2 enzymatic activity, possibly via the upregulation of MT1-MMP expression without a corresponding increase in TIMP expression. This increased collagenase activity increases VSMC motility and their ability to migrate through a collagen type IV lattice. Est/Prog upregulation of MT1-MMP may contribute to the adverse effect of HRT on vascular interventions.