Matrix Metalloproteinase Inhibitors as Investigational and Therapeutic Tools in Unrestrained Tissue Remodeling and Pathological Disorders

Tetracyclines improve experimental lymphatic filariasis pathology by disrupting interleukin-4 receptor-mediated lymphangiogenesis

Lymphatic filariasis is the major global cause of nonhereditary lymphedema. We demonstrate that the filarial nematode Brugia malayi induced lymphatic remodeling and impaired lymphatic drainage following parasitism of limb lymphatics in a mouse model. Lymphatic insufficiency was associated with elevated circulating lymphangiogenic mediators, including vascular endothelial growth factor C. Lymphatic insufficiency was dependent on type 2 adaptive immunity, the interleukin-4 receptor, and recruitment of C-C chemokine receptor-2–positive monocytes and alternatively activated macrophages with a prolymphangiogenic phenotype. Oral treatments with second-generation tetracyclines improved lymphatic function, while other classes of antibiotic had no significant effect. Second-generation tetracyclines directly targeted lymphatic endothelial cell proliferation and modified type 2 prolymphangiogenic macrophage development. Doxycycline treatment impeded monocyte recruitment, inhibited polarization of alternatively activated macrophages, and suppressed T cell adaptive immune responses following infection. Our results determine a mechanism of action for the antimorbidity effects of doxycycline in filariasis and support clinical evaluation of second-generation tetracyclines as affordable, safe therapeutics for lymphedemas of chronic inflammatory origin.

Association of Circulating and Aortic Zinc and Copper Levels with Clinical Abdominal Aortic Aneurysm: a Meta-analysis

It remains obscure whether circulating aortic zinc (Zn) and copper (Cu) levels are associated with the progress of human abdominal aortic aneurysms (AAA). Therefore, we conducted a meta-analysis to explore this relationship. A literature search on circulating and aortic zinc and copper levels and AAA patients was conducted using online databases including PubMed, Embase, and Cochrane up to March 20, 2019. To compare Zn and Cu concentrations in AAA patients with those in aortic occlusive disease (AOD) patients or healthy aorta donors or healthy blood donors, pooled weighted mean difference (WMD) and its 95% confidence interval (CI) were calculated. Subgroup analysis, sensitivity analysis, and meta-regression analysis were applied to explain the heterogeneity and evaluate the robustness of combined results. A total of 10 cross-sectional studies, including 252 cases and 304 controls, were used for meta-analysis. We found that circulating zinc and Zn/Cu ratio in AAA patients were significantly lower [WMD (95%CI): - 2.23 (- 4.10, - 0.36); - 0.18 (- 0.31, - 0.05), respectively] than those in non-AAA patients. Similarly, aneurysmal aorta had significantly lower zinc levels and Zn/Cu ratio [WMD (95%CI): - 9.22 (- 15.37, - 3.07); - 6.46 (- 10.14, - 2.77), respectively] than those in control group. No difference in circulating or aortic copper levels was noted between AAA patients and control group [WMD (95%CI): - 0.24 (- 2.09, 1.61); 0.30 (- 0.01, 0.61) , respectively]. Our meta-analysis suggests that zinc levels and Zn-Cu ratio, but not copper levels, may influence aneurysmal progress of AAA.

Current Status and Perspectives of Protease Inhibitors and Their Combination with Nanosized Drug Delivery Systems for Targeted Cancer Therapy

In cancer treatments, many natural and synthetic products have been examined; among them, protease inhibitors are promising candidates for anti-cancer agents. Since dysregulated proteolytic activities can contribute to tumor development and metastasis, antagonization of proteases with tailored inhibitors is an encouraging approach. Although adverse effects of early designs of these inhibitors disappeared after the introduction of next-generation agents, most of the proposed inhibitors did not pass the early stages of clinical trials due to their nonspecific toxicity and lack of pharmacological effects. Therefore, new applications that modulate proteases more specifically and serve their programmed way of administration are highly appreciated. In this context, nanosized drug delivery systems have attracted much attention because preliminary studies have demonstrated that the therapeutic capacity of inhibitors has been improved significantly with encapsulated formulation as compared to their free forms. Here, we address this issue and discuss the current application and future clinical prospects of this potential combination towards targeted protease-based cancer therapy.

Synovial Tissue Proteins and Patient-Specific Variables as Predictive Factors for Temporomandibular Joint Surgery

Our knowledge of synovial tissues in patients that are scheduled for surgery as a result of temporomandibular joint (TMJ) disorders is limited. Characterising the protein profile, as well as mapping clinical preoperative variables, might increase our understanding of pathogenesis and forecast surgical outcome. A cohort of 100 patients with either disc displacement, osteoarthritis, or chronic inflammatory arthritis (CIA) was prospectively investigated for a set of preoperative clinical variables. During surgery, a synovial tissue biopsy was sampled and analysed via multi-analytic profiling. The surgical outcome was classified according to a predefined set of outcome criteria six months postoperatively. Higher concentrations of interleukin 8 (p = 0.049), matrix metalloproteinase 7 (p = 0.038), lumican (p = 0.037), and tissue inhibitor of metalloproteinase 2 (p = 0.015) were significantly related to an inferior surgical outcome. Several other proteins, which were not described earlier in the TMJ synovia, were detected but not related to surgical outcome. Bilateral masticatory muscle palpation pain had strong association to a poor outcome that was related to the diagnoses disc displacement and osteoarthritis. CIA and the patient-reported variable TMJ disability might be related to an unfavourable outcome according to the multivariate model. These findings of surgical predictors show potential in aiding clinical decision-making and they might enhance the understanding of aetiopathogenesis in TMJ disorders.

Insight on Ameliorative Role of Selenium Nanoparticles and Niacin in Wound Healing on Adult Female Albino Mice

Background:

Wound healing is a complex process necessary for repairing damaged tissues and preventing infection. Selenium nanoparticles (Se NPs) were known due to their antioxidant and antimicrobial effects, also niacin has angiogenesis and antioxidant effects that are important in wound healing.

Objective:

The present study was conducted to investigate the effect of Se NPs and niacin in reducing and accelerating the wound healing time in mice.

Methods:

A simple wet chemical method has been modified to synthesize Se NPs in order to investigate their effect and niacin on reducing the wound healing in 80 adult female albino mice (250 mm2 full thickness open excision wound) that were divided into eight groups (10 mice/each). After 30-days, the mice were sacrificed, blood and tissue samples were taken for analysis.

Results:

The results showed that the percentage of wound area had been significantly reduced in Se NPs and niacin treated groups compared to the positive control. The level of Vascular Endothelial cell Growth Factor and Collagenase I in Se NPs and niacin groups significantly exceed those of other groups while Nitric Oxide (NO) was significantly decreased in treated groups. Liver and kidney functions showed the lower toxicity effect of Se NPs and niacin. Skin tissue showed the wound healing effect of Se NPs and niacin by regenerating skin layer compared to the positive group.

Conclusion:

Se NPs and niacin play an important role in accelerating and reducing the time of wound healing while they were antagonistic to each other.

Comparison of two ASC-derived therapeutics in an in vitro OA model: secretome versus extracellular vesicles

BACKGROUND

In the last years, several clinical trials have proved the safety and efficacy of adipose-derived stem/stromal cells (ASC) in contrasting osteoarthritis (OA). Since ASC act mainly through paracrine mechanisms, their secretome (conditioned medium, CM) represents a promising therapeutic alternative. ASC-CM is a complex cocktail of proteins, nucleic acids, and lipids released as soluble factors and/or conveyed into extracellular vesicles (EV). Here, we investigate its therapeutic potential in an in vitro model of OA.

METHODS

Human articular chondrocytes (CH) were induced towards an OA phenotype by 10 ng/ml TNFα in the presence of either ASC-CM or EV, both deriving from 5 × 10⁵ cells, to evaluate the effect on hypertrophic, catabolic, and inflammatory markers.

RESULTS

Given the same number of donor cells, our data reveal a higher therapeutic potential of ASC-CM compared to EV alone that was confirmed by its enrichment in chondroprotective factors among which TIMP-1 and -2 stand out. In details, only ASC-CM significantly decreased MMP activity (22% and 29% after 3 and 6 days) and PGE2 expression (up to 40% at day 6) boosted by the inflammatory cytokine. Conversely, both treatments down-modulated of ~ 30% the hypertrophic marker COL10A1.

CONCLUSIONS

These biological and molecular evidences of ASC-CM beneficial action on CH with an induced OA phenotype may lay the basis for its future clinical translation as a cell-free therapeutic in the management of OA.

Matrix Metalloproteinases MMP-2 and MMP-9, Their Inhibitors TIMP-1 and TIMP-2, Vascular Endothelial Growth Factor and sVEGFR-2 as Predictive Markers of Ischemic Retinopathy in Patients with Systemic Sclerosis-Case Series Report

Systemic sclerosis (SSc) is an autoimmune connective tissue disorder associated with multiple organ involvement. The aim of the study was to present two SSc patients who were diagnosed with ischemic retinopathy in both eyes. As a background to our case study, we decided to investigate the imbalance of angiogenesis factors in 25 SSc patients in relation to 25 healthy controls. Assays of matrix metalloproteinases-2 and -9 (MMP-2, MMP-9), tissue inhibitor of metalloproteinases-1 (TIMP-1) and -2 (TIMP-2), vascular endothelial growth factor (VEGF), and soluble VEGF receptor-2 (sVEGFR-2) in blood serum and tears were performed. A significantly increased levels of MMP-9 in serum and tears, (p = 0.0375 and p < 0.001, respectively) as well as VEGF/sVEGFR-2 ratio in tears (p < 0.001) were found in the whole SSc patients group compared with controls, while reduced levels of these parameters in patients with ischemic sclerodermic retinopathy were noted. We also observed decreased level MMP-2 in tears and increased levels of TIMP-2 in blood serum and tears of SSc patients with retinal ischemic changes. MMP-9, MMP-2, TIMP-2, and VEGF/sVEGFR-2 may play a crucial role in ischemic retinal degeneration or retinal reorganization in SSc.

The novel relationship between polycystic ovary syndrome and temporomandibular joint disorders

INTRODUCTION

Studies investigating the relationship between sex hormones, inflammatory mediators and joint disorders have reported that sex hormones affect the pathogenesis of joint disorders. We aimed to investigate temporomandibular joint disorder (TJD) in polycystic ovary syndrome (PCOS) and the possible role of systemic mediators and sex hormones in TJD pathogenesis.

MATERIAL AND METHODS

PCOS patients (n = 45) and controls (n = 30) aged 20-40 years, were enrolled in this case-control study. TJD diagnosis was performed by the specialist and blood samples were tested in the early follicular phase and on the 21 st (midluteal) day to investigate the levels of estrogen, progesterone, matrix metalloproteinase (MMP) 1-8-9, interleukin (IL)-1ß and Tumor necrosis factor (TNF)-α.

RESULTS

TJD incidence was significantly higher in PCOS than the control group (51.1% and 6.9% respectively, p < 0.01). Midluteal progesterone (p < 0.01) was lower in PCOS group than the controls (p < 0.01). TNF-α (p < 0.01), MMP 1 (p < 0.01) and MMP 8 (p = 0.02) levels were found significantly higher in PCOS than the control group. Further, Progesterone levels were found significantly lower in TJD (+) PCOS patients than TJD (-) PCOS patients. However, significant difference was not found between the PCOS TJD (+) and PCOS TJD (-) patients for estrogen, MMP 1, MMP 8, MMP 9, TNF-α and IL-1ß.

CONCLUSIONS

TJD frequency was found significantly increased in PCOS patients. Related with this, TJD co-occurrence should be kept in mind in the diagnosing and treatment process of PCOS due to hormonal alteration.

Silencing matrix metalloproteinase-13 (Mmp-13) reduces inflammatory bone resorption associated with LPS-induced periodontal disease in vivo

OBJECTIVES

The aim of this study was to evaluate the effect of specific inhibition of MMP-13 on inflammation and inflammatory bone resorption in a murine model of lipopolysaccharide (LPS)-induced periodontitis.

MATERIALS AND METHODS

Periodontitis was induced in mice by micro-injections of LPS into the gingival tissues adjacent to the palatal surfaces of maxillary molars twice a week for 15 days. Matrix metalloproteinase-13 (Mmp-13) shRNA or a specific biochemical inhibitor were also injected into the same sites in alternating days with the LPS injections. Efficacy of shRNA-mediated silencing of Mmp-13 was verified by quantitative real-time polymerase chain reaction (qPCR) and immunoblot. Bone resorption was assessed by microcomputed tomography (uCT). Histological sections stained with hematoxylin/eosin (H/E) were used in the stereometric analysis of the inflammatory infiltrate. Gingival tissues were used to evaluate expression of Mmp-13, Il-6, Tnf-α, Ptgs2, and Rankl (qPCR). Protein levels of TGF-β and IL-10 in the tissues were determined by enzyme-linked immunosorbent assays (ELISA) or by MMP-13 and p38 immunoblot.

RESULTS

Silencing Mmp-13 expression reduced bone resorption significantly. Expression of Mmp-13, Il-6, and Tnf-α, as well as the protein levels of IL-6 and TNF-α, was reduced in the animals treated with adenovirus-delivered shRNA; however, these effects were not associated with modulation of p38 MAPK signaling. Interestingly, inhibition Mmp-13 did not affect the severity of inflammatory infiltrate.

CONCLUSIONS

Site-specific inhibition of MMP-13 reduced bone resorption and production of inflammatory mediators associated with periodontal disease.

CLINICAL RELEVANCE

The results suggest that site-specific inhibition of MMP-13 may be an interesting strategy to modulate inflammation and reduce bone resorption in osteolytic inflammatory diseases.

Protease inhibitors elicit anti-inflammatory effects in CF mice with Pseudomonas aeruginosa acute lung infection

Pseudomonas aeruginosa is the major respiratory pathogen in patients with cystic fibrosis (CF). P. aeruginosa-secreted proteases, in addition to host proteases, degrade lung tissue and interfere with immune processes. In this study, we aimed at evaluating the possible anti-inflammatory effects of protease inhibitors Marimastat and Ilomastat in the treatment of P. aeruginosa infection. Lung infection with the P. aeruginosa PAO1 strain was established in wild-type and cystic fibrosis transmembrane conductance regulator (CFTR) knock-out C57BL/6 mice expressing a luciferase gene under control of bovine interleukin (IL)-8 promoter. After intratracheal instillation with 150 µM Marimastat and Ilomastat, lung inflammation was monitored by in-vivo bioluminescence imaging and bacterial load in the lungs was assessed. In vitro, the effects of protease inhibitors on PAO1 growth and viability were evaluated. Acute lung infection was established in both wild-type and CFTR knock-out mice. After 24 h, the infection induced IL-8-dependent bioluminescence emission, indicating lung inflammation. In infected mice with ongoing inflammation, intratracheal treatment with 150 µM Marimastat and Ilomastat reduced the bioluminescence signal in comparison to untreated, infected animals. Bacterial load in the lungs was not affected by the treatment, and in vitro the same dose of Marimastat and Ilomastat did not affect PAO1 growth and viability, confirming that these molecules have no additional anti-bacterial activity. Our results show that inhibition of protease activity elicits anti-inflammatory effects in cystic fibrosis (CF) mice with acute P. aeruginosa lung infection. Thus, Marimastat and Ilomastat represent candidate molecules for the treatment of CF patients, encouraging further studies on protease inhibitors and their application in inflammatory diseases.

Quantification of matrix metalloproteinases MMP-8 and MMP-9 in gingival overgrowth

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Protein dot-blot method is suitable to compare expression levels of MMP-8 and MMP-9 in gums.

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The relative levels of MMP-8 and MMP-9 in mild and moderate gingival overgrowth were measured.

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Biological variability among individuals did not affect assay development.

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The protein dot blot was fast, highly sensitive, repeatable and economic.

Background

Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in extracellular matrix remodeling of all body tissues, including oral tissues such as gingival tissue. Expression levels of MMPs are widely studied as important biomarkers for explaining the biochemical mechanisms and evolution of many oral diseases.

Objective

Demonstrate the sensitivity, reproducibility, repeatability, and robustness of the dot blot assay for the relative quantification of MMP-8 and MMP-9 expression levels in patients with GO associated with orthodontic treatment.

Methods

A validated dot blot assay was used to compare the relative expression levels of MMP-8 and MMP-9 in gingival samples. Methodological variability, reproducibility, sensitivity and robustness were determined with the use of control samples from healthy donors (G1). Next, expression levels were measured in gingival tissue from patients with mild and moderate gingival overgrowth associated with orthodontic treatment (G3 and G4) and patients without gingival overgrowth but with a history of using orthodontic appliances (G2).

Results

Dot blot assay demonstrated that MMP-8 and MMP-9 expression levels were higher in patients with gingival overgrowth and distinguished those with moderate clinical grade (G4) from those with mild overgrowth (G3). In addition, patients with a history of orthodontic treatment showed similar expression levels to the control group two years after removing orthodontic appliances.

Conclusions

With the assay used, we were able to detect differences in MMP-8 and MMP-9 expression in patients with different levels of severity of gingival overgrowth. Dot blot could be used to measure MMPs during the onset and progression of gingival overgrowth.

New insights into the pathogenesis of Peyronie's disease: A narrative review

Peyronie's disease (PD) is a benign, progressive fibrotic disorder characterized by scar or plaques within the tunica albuginea (TA) of the penis. This study provides new insights into the pathogenesis of PD based on data from different studies regarding the roles of cytokines, cell signaling pathways, biochemical mechanisms, genetic factors responsible for fibrogenesis. A growing body of literature has shown that PD is a chronically impaired, localized, wound healing process within the TA and the Smith space. It is caused by the influence of different pathological stimuli, most often the effects of mechanical stress during sexual intercourse in genetically sensitive individuals with unusual anatomical TA features, imbalanced matrix metalloproteinase/tissue inhibitor of metalloproteinase (MMP/TIMP), and suppressed antioxidant systems during chronic inflammation. Other intracellular signal cascades are activated during fibrosis along with low expression levels of their negative regulators and transforming growth factor-β1 signaling. The development of multikinase agents with minimal side effects that can block several signal cell pathways would significantly improve fibrosis in PD tissues by acting on common downstream mediators.

Tumor-Cell-Surface Adherable Peptide-Drug Conjugate Prodrug Nanoparticles Inhibit Tumor Metastasis and Augment Treatment Efficacy

Cancer metastasis is the main cause of chemotherapeutic failure. Inhibiting the activity of matrix metalloproteinases (MMPs) is a common strategy for reducing metastasis. However, broad-spectrum MMP-inhibitors (MMPI) may cause undesired side effects. Here, we screened a selective MMP2 inhibitor (CCKIGLFRWR) and linked it with doxorubicin (DOX) to produce an amphiphilic peptide-drug conjugate (PDC). Then novel core-shell nanoparticles were self-assembled from PDC core and modified polylysine (MPL) shell. When the particles were passively targeted to the tumor site, the PDC core was exposed for charge switch of the MPL shell, aggregated for its transformation behavior, and specially adhered to the cell membrane. The disulfide bond between the MMPI peptide and DOX was broken via a low concentration of glutathione-mediated reduction in tumor microenvironment. DOX could effectively enter the tumor cells. Meanwhile, the MMPI peptide could selectively inhibit the activity of the MMP2 and effectively inhibit tumor metastasis.

Matrix Metalloproteinases as Biomarkers of Atherosclerotic Plaque Instability

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases responsible for tissue remodeling and degradation of extracellular matrix (ECM) proteins. MMPs may modulate various cellular and signaling pathways in atherosclerosis responsible for progression and rupture of atherosclerotic plaques. The effect of MMPs polymorphisms and the expression of MMPs in both the atherosclerotic plaque and plasma was shown. They are independent predictors of atherosclerotic plaque instability in stable coronary heart disease (CHD) patients. Increased levels of MMPs in patients with advanced cardiovascular disease (CAD) and acute coronary syndrome (ACS) was associated with future risk of cardiovascular events. These data confirm that MMPs may be biomarkers in plaque instability as they target in potential drug therapies for atherosclerosis. They provide important prognostic information, independent of traditional risk factors, and may turn out to be useful in improving risk stratification.

The Anti-Angiogenic Effects of Anti-Human Immunodeficiency Virus Drugs

The growth and metastasis of malignant tumors benefit from the formation of blood vessels within the tumor area. There, new vessels originate from angiogenesis (the sprouting of pre-existing neighboring vessels) and/or vasculogenesis (the mobilization of bone marrow-derived endothelial cell precursors which incorporate in tumor vasculature and then differentiate into mature endothelial cells). These events are induced by soluble molecules (the angiogenic factors) and modulated by endothelial cell interactions with the perivascular matrix. Given angiogenesis/vasculogenesis relevance to tumor progression, anti-angiogenic drugs are often employed to buttress surgery, chemotherapy or radiation therapy in the treatment of a wide variety of cancers. Most of the anti-angiogenic drugs have been developed to functionally impair the angiogenic vascular endothelial growth factor: however, this leaves other angiogenic factors unaffected, hence leading to drug resistance and escape. Other anti-angiogenic strategies have exploited classical inhibitors of enzymes remodeling the perivascular matrix. Disappointingly, these inhibitors have been found toxic and/or ineffective in clinical trials, even though they block angiogenesis in pre-clinical models. These findings are stimulating the identification of other anti-angiogenic compounds. In this regard, it is noteworthy that drugs utilized for a long time to counteract human immune deficiency virus (HIV) can directly and effectively hamper molecular pathways leading to blood vessel formation. In this review the mechanisms leading to angiogenesis and vasculogenesis, and their susceptibility to anti-HIV drugs will be discussed.

Challenges in Matrix Metalloproteinases Inhibition

Matrix metalloproteinases are enzymes that degrade the extracellular matrix. They have different substrates but similar structural organization. Matrix metalloproteinases are involved in many physiological and pathological processes and there is a need to develop inhibitors for these enzymes in order to modulate the degradation of the extracellular matrix (ECM). There exist two classes of inhibitors: endogenous and synthetics. The development of synthetic inhibitors remains a great challenge due to the low selectivity and specificity, side effects in clinical trials, and instability. An extensive review of currently reported synthetic inhibitors and description of their properties is presented.

Structure and Function of Human Matrix Metalloproteinases

The extracellular matrix (ECM) is a macromolecules network, in which the most abundant molecule is collagen. This protein in triple helical conformation is highly resistant to proteinases degradation, the only enzymes capable of degrading the collagen are matrix metalloproteinases (MMPs). This resistance and maintenance of collagen, and consequently of ECM, is involved in several biological processes and it must be strictly regulated by endogenous inhibitors (TIMPs). The deregulation of MMPs activity leads to development of numerous diseases. This review shows MMPs complexity.

Lack of PCSK6 Increases Flow-Mediated Outward Arterial Remodeling in Mice

Proprotein convertases (PCSKs) process matrix metalloproteases and cytokines, but their function in the vasculature is largely unknown. Previously, we demonstrated upregulation of PCSK6 in atherosclerotic plaques from symptomatic patients, localization to smooth muscle cells (SMCs) in the fibrous cap and positive correlations with inflammation, extracellular matrix remodeling and cytokines. Here, we hypothesize that PCSK6 could be involved in flow-mediated vascular remodeling and aim to evaluate its role in the physiology of this process using knockout mice. Pcsk6^−/− and wild type mice were randomized into control and increased blood flow groups and induced in the right common carotid artery (CCA) by ligation of the left CCA. The animals underwent repeated ultrasound biomicroscopy (UBM) examinations followed by euthanization with subsequent evaluation using wire myography, transmission electron microscopy or histology. The Pcsk6^−/− mice displayed a flow-mediated increase in lumen circumference over time, assessed with UBM. Wire myography revealed differences in the flow-mediated remodeling response detected as an increase in lumen circumference at optimal stretch with concomitant reduction in active tension. Furthermore, a flow-mediated reduction in expression of SMC contractile markers SMA, MYH11 and LMOD1 was seen in the Pcsk6^−/− media. Absence of PCSK6 increases outward remodeling and reduces medial contractility in response to increased blood flow.

Destroy to Rebuild: The Connection Between Bone Tissue Remodeling and Matrix Metalloproteinases

Bone is a dynamic organ that undergoes constant remodeling, an energetically costly process by which old bone is replaced and localized bone defects are repaired to renew the skeleton over time, thereby maintaining skeletal health. This review provides a general overview of bone’s main players (bone lining cells, osteocytes, osteoclasts, reversal cells, and osteoblasts) that participate in bone remodeling. Placing emphasis on the family of extracellular matrix metalloproteinases (MMPs), we describe how: (i) Convergence of multiple protease families (including MMPs and cysteine proteinases) ensures complexity and robustness of the bone remodeling process, (ii) Enzymatic activity of MMPs affects bone physiology at the molecular and cellular levels and (iii) Either overexpression or deficiency/insufficiency of individual MMPs impairs healthy bone remodeling and systemic metabolism. Today, it is generally accepted that proteolytic activity is required for the degradation of bone tissue in osteoarthritis and osteoporosis. However, it is increasingly evident that inactivating mutations in MMP genes can also lead to bone pathology including osteolysis and metabolic abnormalities such as delayed growth. We argue that there remains a need to rethink the role played by proteases in bone physiology and pathology.

The Role of Matrix Metalloproteinases in the Epithelial-Mesenchymal Transition of Hepatocellular Carcinoma

The epithelial-mesenchymal transition (EMT) is a transformation process mandatory for the local and distant progression of many malignant tumors, including hepatocellular carcinoma (HCC). Matrix metalloproteinases (MMPs) play significant roles in cellular regeneration, programmed death, angiogenesis, and many other essential tissular functions, involved in the normal development and also in pathological processes, such as the EMT. This paper reviews the roles of MMPs in the EMT involved in HCC invasion, as well as the ancillary roles that MMP cross-activation and tissue inhibitors play in modulating this process. While gelatinases MMP-2 and MMP-9 are the MMPs commonly cited in the EMT of HCC, MMPs belonging to other classes have been proven to be involved in this process, favoring not only invasion and metastasis (MMP-1, MMP-3, MMP-7, MMP-10, MMP-11, MMP-13, MMP-14, MMP-16, MMP-26, and MMP-28) but also angiogenesis (MMP-8 and MMP-10). There is also data suggesting that other MMPs with a suspected or demonstrated role in the EMT of other cancers may also have some degree of involvement in HCC. The auto- and cross-activation of MMPs may complicate this issue, as pinpointing the extent of implication of each MMP may be extremely difficult. The homeostasis between MMPs and their tissue inhibitors is essential in preventing tumor progression, and the disturbance of this stability is another entailed factor in the EMT of HCC, which is addressed herein.

Kangfuxin Oral Liquid Attenuates Bleomycin-Induced Pulmonary Fibrosis via the TGF-β1/Smad Pathway

Idiopathic pulmonary fibrosis (IPF) is a fatal respiratory disease with a poor prognosis characterized by transforming growth factor (TGF)-β-induced proliferation, migration, and differentiation of fibroblasts, resulting in excessive extracellular matrix (ECM) deposition. Whether Kangfuxin oral liquid (KFXOL) has a protective function in pulmonary fibrosis is largely unknown. The goal of this study was to investigate the potential efficacy of KFXOL, as well as the underlying mechanism by which KFXOL regulates pulmonary fibrosis in vivo and in vitro. We found that KFXOL dramatically attenuated intratracheal bleomycin (BLM)-induced pulmonary fibrosis in terms of both severe alveolar architecture destruction and collagen deposition. KFXOL treatment significantly inhibited the proliferation, migration, and differentiation of pulmonary fibroblasts following activation using BLM/TGF-β1 and normalized the expression of ECM deposition-related proteins, including matrix metalloproteinase (MMP)-1, MMP-9, and tissue inhibitor of metalloproteinases 1. These effects were mediated via the inhibition of TGF-β1 and phosphorylated Smad2/3 activation in vivo. Taken together, our data suggest that KFXOL attenuates the development of pulmonary fibrosis via the TGF-β1/Smad signaling pathway and thus has potential utility in the treatment of pulmonary fibrosis.

Novel Matrix Metalloproteinase 12 Selective Radiotracers for Vascular Molecular Imaging

Matrix metalloproteinase-12 (MMP-12) is highly upregulated in several inflammatory diseases, including abdominal aortic aneurysm (AAA). Here we report four novel ^99mTc-labeled radiotracers derived from a highly selective competitive MMP-12 inhibitor. These tracers in their ^99gTc version were assessed in vitro on a set of human metalloproteases and displayed high affinity and selectivity toward MMP-12. Their radiolabeling with ^99mTc was shown to be efficient and stable in both buffer and mouse blood. The tracers showed major differences in their biodistribution and blood clearance. On the basis of its in vivo performance, [^99mTc]-1 was selected for evaluation in murine AAA, where MMP-12 gene expression is upregulated. Autoradiography of aortae at 2 h postinjection revealed high uptake of [^99mTc]-1 in AAA relative to adjacent aorta. Tracer uptake specificity was demonstrated through in vivo competition. This study paves the way for further evaluation of [^99mTc]-1 for imaging AAA and other MMP-12-associated diseases.

FK506 combined with GM6001 prevents tracheal obliteration in a mouse model of heterotopic tracheal transplantation

BACKGROUND

Obliterative bronchiolitis (OB) is the major complication limiting the long-term survival of allografts after lung transplantation. In this study, we investigated the effect of tacrolimus (FK506) combined with GM6001，a matrix metalloproteinase (MMP) inhibitor， on the formation of OB using a mouse heterotopic tracheal transplantation model.

METHODS

Syngeneic tracheal grafts were transplanted heterotopically from BALB/c mice to BALB/c mice. Allografts from C57BL/6 mice were transplanted to BALB/c mice. Isograft group, allograft group, allograft+FK506 group, allograft +GM6001 group and allograft+FK506 + GM6001 group was given respectively intraperitoneal injection of saline, saline, FK506, GM6001 and FK506 + GM6001 once a day. At 28 day after transplantation, OB incidence was determined by hematoxylin-eosin staining and the expressions of MMPs and cytokines were assessed using enzyme linked immunosorbent assay, immunohistochemical assays and western blot assay.

RESULTS

The tracheal occlusion rates of isograft group, allograft group, allograft+FK506 group, allograft+GM6001 group and allograft+FK506 + GM6001 group were 0, 74.1 ± 9.79%, 34.4 ± 6.04%, 40.3 ± 8.77% and 26.5 ± 5.73% respectively. There were significant differences between the latter two groups (P < .001). The serum MMP-8 and MMP-9 levels of allograft group were significantly higher than those of isograft group (P < .05) and had no significant decrease when treated by FK506. The serum MMP-8 and MMP-9 levels of allograft+FK506 + GM6001 group were significantly lower than those of allograft+FK506 group (P < .05). MMP-8 and MMP-9 protein expression in the grafts of allograft+FK506 + GM6001 group were lower than those of allograft+FK506 group verified by immunohistochemical staining and western blotting.

CONCLUSION

FK506 combined with GM6001 could alleviate tracheal obliteration in mouse heterotopic tracheal transplantation model, due to its inhibitory effect on MMPs.

Intra-articular targeting of nanomaterials for the treatment of osteoarthritis

Osteoarthritis is a prevalent and debilitating disease that involves pathological contributions from numerous joint tissues and cells. The joint is a challenging arena for drug delivery, since the joint has poor bioavailability for systemically administered drugs and experiences rapid clearance of therapeutics after intra-articular injection. Moreover, each tissue within the joint presents unique barriers to drug localization. In this review, the various applications of nanotechnology to overcome these drug delivery limitations are investigated. Nanomaterials have reliably shown improvements to retention profiles of drugs within the joint space relative to injected free drugs. Additionally, nanomaterials have been modified through active and passive targeting strategies to facilitate interactions with and localization within specific joint tissues such as cartilage and synovium. Last, the limitations of drawing cross-study comparisons, the implications of synovial fluid, and the potential importance of multi-modal therapeutic strategies are discussed. As emerging, cell-specific disease modifying osteoarthritis drugs continue to be developed, the need for targeted nanomaterial delivery will likely become critical for effective clinical translation of therapeutics for osteoarthritis. STATEMENT OF SIGNIFICANCE: Improving drug delivery to the joint is a pressing clinical need. Over 27 million Americans live with osteoarthritis, and this figure is continuously expanding. Numerous drugs have been investigated but have failed in clinical trials, likely related to poor bioavailability to target cells. This article comprehensively reviews the advances in nano-scale delivery vehicles designed to overcome the delivery barriers in the joint. This is the first review to analyze active and passive targeting strategies systematically for different target sites while also delineating between tissue homing and whole joint retention. By bringing together the lessons learned across numerous nano-scale platforms, researchers may be able to hone future nanomaterial designs, allowing emerging therapeutics to perform with clinically relevant efficacy and disease modifying potential.

Development of calcific aortic valve disease: Do we know enough for new clinical trials?

Calcific aortic valve disease (CAVD), previously thought to represent a passive degeneration of the valvular extracellular matrix (VECM), is now regarded as an intricate multistage disorder with sequential yet intertangled and interacting underlying processes. Endothelial dysfunction and injury, initiated by disturbed blood flow and metabolic disorders, lead to the deposition of low-density lipoprotein cholesterol in the VECM further provoking macrophage infiltration, oxidative stress, and release of pro-inflammatory cytokines. Such changes in the valvular homeostasis induce differentiation of normally quiescent valvular interstitial cells (VICs) into synthetically active myofibroblasts producing excessive quantities of the VECM and proteins responsible for its remodeling. As a result of constantly ongoing degradation and re-deposition, VECM becomes disorganised and rigid, additionally potentiating myofibroblastic differentiation of VICs and worsening adaptation of the valve to the blood flow. Moreover, disrupted and excessively vascularised VECM is susceptible to the dystrophic calcification caused by calcium and phosphate precipitating on damaged collagen fibers and concurrently accompanied by osteogenic differentiation of VICs. Being combined, passive calcification and biomineralisation synergistically induce ossification of the aortic valve ultimately resulting in its mechanical incompetence requiring surgical replacement. Unfortunately, multiple attempts have failed to find an efficient conservative treatment of CAVD; however, therapeutic regimens and clinical settings have also been far from the optimal. In this review, we focused on interactions and transitions between aforementioned mechanisms demarcating ascending stages of CAVD, suggesting a predisposing condition (bicuspid aortic valve) and drug combination (lipid-lowering drugs combined with angiotensin II antagonists and cytokine inhibitors) for the further testing in both preclinical and clinical trials.

Adipose-derived stromal cell secretome reduces TNFα-induced hypertrophy and catabolic markers in primary human articular chondrocytes

Recent clinical trials show the efficacy of Adipose-derived Stromal Cells (ASCs) in contrasting the osteoarthritis scenario. Since it is quite accepted that ASCs act predominantly through a paracrine mechanism, their secretome may represent a valid therapeutic substitute. The aim of this study was to investigate the effects of ASC conditioned medium (ASC-CM) on TNFα-stimulated human primary articular chondrocytes (CHs). CHs were treated with 10 ng/ml TNFα and/or ASC-CM (1:5 recipient:donor cell ratio). ASC-CM treatment blunted TNFα-induced hypertrophy, reducing the levels of Osteocalcin (-37%), Collagen X (-18%) and MMP-13 activity (-61%). In addition, it decreased MMP-3 activity by 59%. We showed that the reduction of MMP activity correlates to the abundance of TIMPs (Tissue Inhibitors of MMPs) in ASC secretome (with TIMP-1 exceeding 200 ng/ml and TIMP-2/3 in the ng/ml range) rather than to a direct down-modulation of the expression and/or release of these proteases. In addition, ASC secretome contains high levels of other cartilage protecting factors, i.e. OPG and DKK-1. ASC-CM comprises cartilage-protecting factors and exerts anti-hypertrophic and anti-catabolic effects on TNFα-stimulated CHs in vitro. Our results support a future use of this cell-derived but cell-free product as a therapeutic approach in the management of osteoarthritis.

Inhibition of MMPs and ADAM/ADAMTS

Matrix metalloproteinases (MMPs), A Disintegrin and Metalloproteinase (ADAM) and A Disintegrin and Metalloproteinase with Thrombospondin Motif (ADAMTS) are zinc-dependent endopeptidases that play a critical role in the destruction of extracellular matrix proteins and, the shedding of membrane-bound receptor molecules in various forms of arthritis and other diseases. Under normal conditions, MMP, ADAM and ADAMTS gene expression aids in the maintenance of homeostasis. However, in inflamed synovial joints characteristic of rheumatoid arthritis and osteoarthritis. MMP, ADAM and ADAMTS production is greatly increased under the influence of pro-inflammatory cytokines. Analyses based on medicinal chemistry strategies designed to directly inhibit the activity of MMPs have been largely unsuccessful when these MMP inhibitors were employed in animal models of rheumatoid arthritis and osteoarthritis. This is despite the fact that these MMP inhibitors were largely able to suppress pro-inflammatory cytokine-induced MMP production in vitro. A focus on ADAM and ADAMTS inhibitors has also been pursued. Thus, recent progress has identified the "sheddase" activity of ADAMs as a viable target and the development of GW280264X is an experimental ADAM17 inhibitor. Of note, a monoclonal antibody, GLPG1972, developed as an ADAMTS-5 inhibitor, entered a Phase I OA clinical trial. However, the failure of many of these previously developed inhibitors to move beyond the preclinical testing phase has required that novel strategies be developed that are designed to suppress both MMP, ADAM and ADAMTS production and activity.

Maternal cardiac messenger RNA expression of extracellular matrix proteins in mice during pregnancy and the postpartum period

IMPACT STATEMENT

This study provides the first comprehensive analysis of extracellular matrix protein (ECM) gene expression combined with echocardiographic analyses of heart functional parameters in the murine heart during pregnancy and the early postpartum period. Our findings show regulation of all Timp, selected Mmps, and Col1a1, Col3a1, and Col8a1 mRNA levels with reproductive status, with the greatest number of significant changes occurring in the early postpartum period. Left ventricle cardiac diastolic parameters were the first to change during pregnancy and remained elevated postpartum, whereas systolic parameters were increased in late pregnancy and began to recover during the first week postpartum. These novel findings indicate that although some ECM genes are elevated during late pregnancy, that the postpartum period is a time of robust altered ECM gene expression. These studies provide a basis for examining ECM proteins and their activities in the normal pregnant and postpartum heart and in models of postpartum cardiomyopathy.

Silencing of Astrocyte elevated gene-1 (AEG-1) inhibits proliferation, migration, and invasiveness, and promotes apoptosis in pancreatic cancer cells

To investigate the role of Astrocyte elevated gene-1 (AEG-1) in the development and progress of pancreatic cancer, short hairpin RNA (shRNA) was inserted into the RNA interference vector to knock-down the endogenous AEG-1 in two pancreatic cancer cell lines: AsPC-1 and PANC-1. Our results showed that silencing of AEG-1 suppressed the proliferation, colony formation ability, and cell stemness of AsPC-1 and PANC-1 cells, and inhibited their G1-to-S phase transition. Results from apoptosis assay showed that knock-down of AEG-1 led to cell apoptosis. The expression of anti-apoptotic Bcl-2 was downregulated and that of the pro-apoptotic Bax and cleaved caspase-3 was upregulated in AEG-1-silenced pancreatic cancer cells. Further, the capability of AEG-1-silenced cells to migrate and to invade through the Matrigel-coated membrane was weaker, and the expression of matrix metallopeptidase 2 (MMP-2) and MMP-9 were decreased. Moreover, the AKT-β-catenin signaling pathway was inhibited in the cells with knock-down of AEG-1. In addition, the growth of xenograft tumors formed by AsPC-1 and PANC-1 cells was suppressed by AEG-1 shRNA. In conclusion, our study demonstrates that pancreatic cancer cells require AEG-1 to maintain their survival and metastasis, suggesting AEG-1 as a potential target for the treatment of pancreatic cancers.

Investigational drugs for the treatment of osteoarthritis, an update on recent developments

INTRODUCTION

Osteoarthritis (OA) is the leading cause of pain, loss of function, and disability among elderly, with the knee the most affected joint. It is a heterogeneous condition characterized by complex and multifactorial etiologies which contribute to the broad variation in symptoms presentation and treatment responses that OA patients present. This poses a challenge for the development of effective treatment on OA.

AREAS COVERED

This review will discuss recent development of agents for the treatment of OA, updating our previous narrative review published in 2015. They include drugs for controlling local and systemic inflammation, regulating articular cartilage, targeting subchondral bone, and relieving pain.

EXPERT OPINION

Although new OA drugs such as monoclonal antibodies have shown marked effects and favorable tolerance, current treatment options for OA remain limited. The authors believe there is no miracle drug that can be used for all OA patients'; treatment and disease stage is crucial for the effectiveness of drugs. Therefore, early diagnosis, phenotyping OA patients and precise therapy would expedite the development of investigational drugs targeting at symptoms and disease progression of OA.

Matrix metalloproteinases in pro-atherosclerotic arterial remodeling

Matrix metalloproteinases (MMPs) is a family of Zn²⁺ endopeptidases that process various components of the extracellular matrix. These enzymes are also involved in activation and inhibition of signaling cascades through proteolytic cleavage of surface receptors. Moreover, MMPs play a key role in tissue remodeling and and repair. Dysregulation of MMPs is observed in patholofgical conditions, including atherosclerosis, which is associated with hyperactivation of MMPs, aberrant tissue remodeling and neovascularization of the growing atherosclerotic plaques. This makes MMPs interesting therapeutic targets that can be employed for developing novel therapies to treat atherosclerosis and its complications. Currently, a growing number of synthetic MMP inhibitors is available. In this review, we will discuss the role of these enzymes in atherosclerosis pathology and the ways of their pothential therapeutic use.

Genetic polymorphisms of matrix metalloproteinases 1-3 and their inhibitor are not associated with premature labor

Aim

Extracellular matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of metalloproteinases [TIMPs]) are involved in the breakdown of fetal membranes before delivery. Our aim was to investigate the occurrence of any polymorphism on genes coding for MMPs 1-3 and TIMP 2 in preterm laboring patients as a potential source of this phenomenon. This question has not been studied before.

Methodology & results

A prospective population study was performed in a Greek university hospital. Group A (control) included 66 women with no symptoms of premature labor. Group B (research) comprised 66 women, exhibiting signs of threatened preterm labor. No statistically significant difference in polymorphism, both in the distribution of genotype as well as allele frequencies, was detected between the two groups. This also applied to gestational age less or greater than 32 weeks.

Conclusion

Gene polymorphisms of MMP 1-3 and TIMP 2 are not associated with premature rupture of membranes/contractions, as well as gestational age at preterm labor.

Can photobiomodulation associated with implantation of mesenchymal adipose-derived stem cells attenuate the expression of MMPs and decrease degradation of type II collagen in an experimental model of osteoarthritis?

This study aimed to determine whether photobiomodulation therapy (PBMT) could improve the bioavailability and chondroprotective benefits of mesenchymal stem cells injected into the knees of rats used as an experimental model of osteoarthritis (OA) as well as reduce the expression of matrix metalloproteinases (MMPs) and degradation of type II collagen (COL2-1) in the cartilage. Adipose-derived stem/stromal cells (ADSCs) were collected from three male Fischer 344 rats and characterized by flow cytometry. Fifty female Fischer 344 rats were distributed into five groups of 10 animals each. These groups were as follows: control, OA, OA PBMT, OA ADSC, and OA ADSC PBMT. OA was induced in the animals using a 4% papain solution. Animals from the OA ADSC and OA ADSC PBMT groups received an intra-articular injection of 10 × 10⁶ ADSCs and were treated with PBMT by irradiation (wavelength: 808 nm, power: 50 mW, energy: 42 J, energy density: 71.2 J/cm², spot size: 0.028). Euthanasia was performed 7 days after the first treatment. The use of PBMT alone and the injection of ADSCs resulted in downregulation of pro-inflammatory cytokines and MPs in cartilage compared to the OA group. PBMT and ADSCs caused upregulation of tissue inhibitors of MPs 1 and 2 and mRNA and protein expression of COL2-1 in cartilage compared to the OA group. The intra-articular injection of ADSCs and PBMT prevented joint degeneration resulting from COL2-1 degradation and modulated inflammation by downregulating cytokines and MMPs in the OA group.

Proteinases and their receptors in inflammatory arthritis: an overview

Proteinases are enzymes with established roles in physiological and pathological processes such as digestion and the homeostasis, destruction and repair of tissues. Over the past few years, the hormone-like properties of circulating proteinases have become increasingly appreciated. Some proteolytic enzymes trigger cell signalling via proteinase-activated receptors, a family of G protein-coupled receptors that have been implicated in inflammation and pain in inflammatory arthritis. Proteinases can also regulate ion flux owing to the cross-sensitization of transient receptor potential cation channel subfamily V members 1 and 4, which are associated with mechanosensing and pain. In this Review, the idea that proteinases have the potential to orchestrate inflammatory signals by interacting with receptors on cells within the synovial microenvironment of an inflamed joint is revisited in three arthritic diseases: osteoarthritis, spondyloarthritis and rheumatoid arthritis. Unanswered questions are highlighted and the therapeutic potential of modulating this proteinase-receptor axis for the management of disease in patients with these types of arthritis is also discussed.

Tissue Inhibitor of Metalloprotease-2 (TIMP-2): Bioprocess Development, Physicochemical, Biochemical, and Biological Characterization of Highly Expressed Recombinant Protein

Tissue inhibitor of metalloprotease-2 (TIMP-2) is a secreted 21 kDa multifunctional protein first described as an endogenous inhibitor of matrix metalloproteinases (MMPs) that prevents breakdown of the extracellular matrix often observed in chronic diseases. TIMP-2 diminishes the level of growth factor-mediated cell proliferation in vitro, as well as neoangiogenesis and tumor growth in vivo independent of its MMP inhibitory activity. These physiological properties make TIMP-2 an excellent candidate for further preclinical development as a biologic therapy of cancer. Here we present a straightforward bioprocessing methodology that yields >35 mg/L recombinant human TIMP-2 6XHis-tagged protein (rhTIMP-2) from suspension cultures of HEK-293-F cells. Enhanced rhTIMP-2-6XHis yields were achieved by optimization of both TIMP-2 cDNA codon sequence and cell culture conditions. Using a two-step chromatographic process, we achieved >95% purity with minimal processing losses. Purified rhTIMP-2-6XHis was free of mouse antigen contamination. Circular dichroism spectroscopy indicated a well-folded rhTIMP-2-6XHis that is highly stable and refractory to pH changes. Two-dimensional heteronuclear single-quantum coherence nuclear magnetic resonance of full length rhTIMP-2-6XHis also indicated a monodisperse, well-folded protein preparation. Purified rhTIMP-2-6XHis inhibited MMP-2 enzymatic activity in a dose-dependent fashion with an IC50 of ∼1.4 nM. Pretreatment of A549 lung cancer and JygMC(A) triple-negative breast cancer cells with rhTIMP-2-6XHis in low-nanomolar amounts inhibited EGF-induced proliferation to basal (unstimulated) levels. This study therefore not only offers a robust bioprocess methodology for rhTIMP-2 production but also characterizes critical physicochemical and biological attributes that are useful for monitoring quality control of the production process.

The Long Noncoding RNA HOTAIR in Breast Cancer: Does Autophagy Play a Role?

HOTAIR (HOX transcript antisense RNA) plays a critical role in chromatin dynamics through the interaction with histone modifiers resulting in transcriptional gene silencing. The promoter of the HOTAIR gene contains multiple estrogen response elements (EREs) and is transcriptionally activated by estradiol in estrogen receptor-positive breast cancer cells. HOTAIR competes with BRCA1, a critical protein in breast cancer and is a critical regulator of genes involved in epithelial-to-mesenchymal transition. It mediates an oncogenic action of c-Myc, essential for breast carcinogenesis. The carcinogenic action of HOTAIR was confirmed in breast cancer stem-like cells, in which it was essential for self-renewal and proliferation. Several miRNAs regulate the expression of HOTAIR and HOTAIR interacts with many miRNAs to support cancer transformation. Many studies point at miR-34a as a major component of HOTAIR–miRNAs–cancer cross-talk. The most important role of HOTAIR can be attributed to cancer progression as its overexpression stimulates invasion and metastasis. HOTAIR can regulate autophagy, important for breast cancer cells survival, through the interaction with miRNAs specific for autophagy genes and directly with these genes. The role of HOTAIR-mediated autophagy in breast cancer progression can be underlined by its interaction with matrix metalloproteinases, essential for cancer invasion, and β-catenin can be important for this interaction. Therefore, there are several mechanisms of the interplay between HOTAIR and autophagy important for breast cancer, but further studies are needed to determine more details of this interplay.