Nerve growth factor activation of Erk-1 and Erk-2 induces matrix metalloproteinase-9 expression in vascular smooth muscle cells

S1P promotes corneal trigeminal neuron differentiation and corneal nerve repair via upregulating nerve growth factor expression in a mouse model

Corneal disease was the most critical cause of vision loss. This study aimed to research a new method and provide a theoretical basis for treating corneal injury. A mice corneal epithelial injury model was constructed by the method of mechanical curettage. Models were treated with sphingosine 1-phosphate (S1P) and si-Spns2. An immunofluorescence assay was used to detect βIII-tubulin. The expressions of neurotrophic factor, S1P transporter, and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway-related proteins were detected by western blot. Hematoxylin-eosin staining was processed to detect the effect of SIP on corneal repair in mice. si-Spns2 inhibited the effect of S1P. S1P significantly repaired the corneal injury, while si-Spns2 treatment made it more severe. Moreover, S1P could significantly increase the levels of NGF, BDNF, GDNF, Spns2, and p-ERK1/2. si-Spns2 inhibits the effect of S1P in the expression of these proteins. S1P significantly increased axonal differentiation of trigeminal ganglion neurons, which was inhibited after si-Spns2 treatment. S1P promoted corneal trigeminal neuron differentiation and corneal nerve repair via upregulating nerve growth factor expression in a mouse model. Treatment of corneal injury by S1P may be an effective approach.

Do Neurotrophins Connect Neurological Disorders and Heart Diseases?

Neurotrophins (NTs) are one of the most characterized neurotrophic factor family members and consist of four members in mammals. Growing evidence suggests that there is a complex inter- and bi-directional relationship between central nervous system (CNS) disorders and cardiac dysfunction, so-called "brain-heart axis". Recent studies suggest that CNS disorders, including neurodegenerative diseases, stroke, and depression, affect cardiovascular function via various mechanisms, such as hypothalamic-pituitary-adrenal axis augmentation. Although this brain-heart axis has been well studied in humans and mice, the involvement of NT signaling in the axis has not been fully investigated. In the first half of this review, we emphasize the importance of NTs not only in the nervous system, but also in the cardiovascular system from the embryonic stage to the adult state. In the second half, we discuss the involvement of NTs in the pathogenesis of cardiovascular diseases, and then examine whether an alteration in NTs could serve as the mediator between neurological disorders and heart dysfunction. The further investigation we propose herein could contribute to finding direct evidence for the involvement of NTs in the axis and new treatment for cardiovascular diseases.

Targeting the Nerve Growth Factor Signaling Impairs the Proliferative and Migratory Phenotype of Triple-Negative Breast Cancer Cells

Triple-negative breast cancer is a heterogeneous disease that still lacks specific therapeutic approaches. The identification of new biomarkers, predictive of the disease's aggressiveness and pharmacological response, is a challenge for a more tailored approach in the clinical management of patients. Nerve growth factor, initially identified as a key factor for neuronal survival and differentiation, turned out to be a multifaceted molecule with pleiotropic effects in quite divergent cell types, including cancer cells. Many solid tumors exhibit derangements of the nerve growth factor and its receptors, including the tropomyosin receptor kinase A. This receptor is expressed in triple-negative breast cancer, although its role in the pathogenesis and aggressiveness of this disease is still under investigation. We now report that triple-negative breast cancer-derived MDA-MB-231 and MDA-MB-453 cells express appreciable levels of tropomyosin receptor kinase A and release a biologically active nerve growth factor. Activation of tropomyosin receptor kinase by nerve growth factor treatment positively affects the migration, invasion, and proliferation of triple-negative breast cancer cells. An increase in the size of triple-negative breast cancer cell spheroids is also detected. This latter effect might occur through the nerve growth factor-induced release of matrix metalloproteinase 9, which contributes to the reorganization of the extracellular matrix and cell invasiveness. The tropomyosin receptor kinase A inhibitor GW441756 reverses all these responses. Co-immunoprecipitation experiments in both cell lines show that nerve growth factor triggers the assembly of the TrkA/β1-integrin/FAK/Src complex, thereby activating several downstream effectors. GW441756 prevents the complex assembly induced by nerve growth factor as well as the activation of its dependent signaling. Pharmacological inhibition of the tyrosine kinases Src and FAK (focal adhesion kinase), together with the silencing of β1-integrin, shows that the tyrosine kinases impinge on both proliferation and motility, while β1-integrin is needed for motility induced by nerve growth factor in triple-negative breast cancer cells. The present data support the key role of the nerve growth factor/tropomyosin receptor kinase A pathway in triple-negative breast cancer and offer new hints in the diagnostic and therapeutic management of patients.

NGF nanoparticles enhance the potency of transplanted human umbilical cord mesenchymal stem cells for myocardial repair

In this study, we investigated whether human umbilical cord mesenchymal stem cell (hUCMSC) fibrin patches loaded with nerve growth factor (NGF) poly(lactic-co-glycolic acid) (PLGA) nanoparticles could enhance the therapeutic potency of hUCMSCs for myocardial infarction (MI). In vitro, NGF significantly improved the proliferation of hUCMSCs and mitigated cytotoxicity and apoptosis under hypoxic injury. NGF also promoted the paracrine effects of hUCMSCs on angiogenesis and cardiomyocyte protection. The tyrosine kinase A (TrkA) and phosphoinositide 3-kinase (PI3K)-serine/threonine protein kinase (Akt) signaling pathways in hUCMSCs were involved in the NGF-induced protection. NGF PLGA nanoparticles continued to release NGF for at least 1 mo and also exerted a protective effect on hUCMSCs, the same with free NGF. In vivo, we treated MI mice with nothing (MI group), a cell-free fibrin patch with blank PLGA nanoparticles (MI + OP group), a cell-free fibrin patch with NGF nanoparticles (MI + NGF group), and hUCMSC fibrin patches with blank PLGA nanoparticles (MI + MSC group) or NGF PLGA nanoparticles (MSC + NGF group). Among these groups, the MSC + NGF group exhibited the best cardiac contractile function, the smallest infarct size, and the thickest ventricular wall. The application of NGF PLGA nanoparticles significantly improved the retention of transplanted hUCMSCs and enhanced their ability to reduce myocardial apoptosis and promote angiogenesis in the mouse heart after MI. These findings demonstrate the promising therapeutic potential of hUCMSC fibrin cardiac patches loaded with NGF PLGA nanoparticles.NEW & NOTEWORTHY NGF PLGA nanoparticles can exert a protective effect on hUCMSCs and promote the paracrine effects of hUCMSCs on angiogenesis and cardiomyocyte protection through TrkA-PI3K/Akt signaling pathway, the same with free NGF. The application of NGF PLGA nanoparticles in the hUCMSC fibrin cardiac patches can significantly improve the retention of transplanted hUCMSCs and enhance their ability to reduce myocardial apoptosis and promote angiogenesis in the mouse heart after MI.

Brain-Derived Neurotrophic Factor Expression and Signaling in Different Perivascular Adipose Tissue Depots of Patients With Coronary Artery Disease

Background

Brain‐derived neurotrophic factor (BDNF) is expressed in neuronal and nonneuronal cells and may affect vascular functions via its receptor, tropomyosin‐related kinase B (TrkB). In this study, we determined the expression of BDNF in different perivascular adipose tissue (PVAT) depots of patients with established coronary atherosclerosis.

Methods and Results

Serum, vascular tissue, and PVAT surrounding the proximal aorta (C‐PVAT) or internal mammary artery (IMA‐PVAT) was obtained from 24 patients (79% men; mean age, 71.7±9.7 years; median body mass index, 27.4±4.8 kg/m²) with coronary atherosclerosis undergoing elective coronary artery bypass surgery. BDNF protein levels were significantly higher in C‐PVAT compared with IMA‐PVAT, independent of obesity, metabolic syndrome, or systemic biomarkers of inflammation. mRNA transcripts of TrkB, the BDNF receptor, were significantly reduced in aorta compared with IMA. Vessel wall TrkB immunosignals colocalized with cells expressing smooth muscle cell markers, and confocal microscopy and flow cytometry confirmed BDNF receptor expression in human aortic smooth muscle cells. Significantly elevated levels of protein tyrosine phosphatase 1B, a negative regulator of TrkB signaling in the brain, were also observed in C‐PVAT. In vitro, inhibition of protein tyrosine phosphatase 1B blunted the effects of BDNF on smooth muscle cell proliferation, migration, differentiation, and collagen production, possibly by upregulation of low‐affinity p75 neurotrophin receptors. Expression of nerve growth factor or its receptor tropomyosin‐related kinase A did not differ between C‐PVAT and IMA‐PVAT.

Conclusions

Elevated expression of BDNF in parallel with local upregulation of negative regulators of neurotrophin signaling in perivascular fat and lower TrkB expression suggest that vascular BDNF signaling is reduced or lost in patients with coronary atherosclerosis.

Neurotrophin 3 upregulates proliferation and collagen production in human aortic valve interstitial cells: a potential role in aortic valve sclerosis

Calcific aortic valve disease (CAVD) is a leading cardiovascular disorder in the elderly. Diseased aortic valves are characterized by sclerosis (fibrosis) and nodular calcification. Sclerosis, an early pathological change, is caused by aortic valve interstitial cell (AVIC) proliferation and overproduction of extracellular matrix (ECM) proteins. However, the mechanism of aortic valve sclerosis remains unclear. Recently, we observed that diseased human aortic valves overexpress growth factor neurotrophin 3 (NT3). In the present study, we tested the hypothesis that NT3 is a profibrogenic factor to human AVICs. AVICs isolated from normal human aortic valves were cultured in M199 growth medium and treated with recombinant human NT3 (0.10 µg/ml). An exposure to NT3 induced AVIC proliferation, upregulated the production of collagen and matrix metalloproteinase (MMP), and augmented collagen deposition. These changes were abolished by inhibition of the Trk receptors. NT3 induced Akt phosphorylation and increased cyclin D1 protein levels in a Trk receptor-dependent fashion. Inhibition of Akt abrogated the effect of NT3 on cyclin D1 production. Furthermore, inhibition of either Akt or cyclin D1 suppressed NT3-induced cellular proliferation and MMP-9 and collagen production, as well as collagen deposition. Thus, NT3 upregulates cellular proliferation, ECM protein production, and collagen deposition in human AVICs. It exerts these effects through the Trk-Akt-cyclin D1 cascade. NT3 is a profibrogenic mediator in human aortic valve, and overproduction of NT3 by aortic valve tissue may contribute to the mechanism of valvular sclerosis.

Combination of rosuvastatin and probucol inhibits MMP-9 expression via upregulation of miR-497 in cultured HUVECs and apoE knockout mice

This study deciphered the molecular mechanisms of the inhibition of MMP-9 expression using rosuvastatin in cultured human umbilical vein endothelial cells (HUVECs) and apoE knockout mice and whether the combination of rosuvastatin and probucol enhanced this effect. The role that microRNA (miR)-497 plays in the regulation of MMP-9 expression was evaluated in cultured HUVECs and apoE knockout mice using quantitative real-time reverse transcription polymerase chain reaction and Western blotting. First, TNFα significantly increased mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/ERK) signaling and MMP-9 levels, and the transfection of miR-497 prevented this increase. The converse results were obtained after miR-497 suppression. Second, the administration of rosuvastatin or the combination of two drugs decreased MAPK/ERK signaling and MMP-9 levels, and the suppression of miR-497 upregulated these levels. Third, the administration of rosuvastatin or the combination of two drugs increased miR-497 expression levels in the aortas of apoE knockout mice, but the levels of serum lipids and plaque areas decreased, which improved plaque components and decreased the MAPK/ERK signaling and MMP-9 levels. Finally, the combination of the two drugs was more effective than the use of rosuvastatin alone. Rosuvastatin inhibits MMP-9 expression by upregulating miR-497 in HUVECs and apoE knockout mice, and the combination of rosuvastatin and probucol enhances this effect.

Can Wound Exudate from Venous Leg Ulcers Measure Wound Pain Status?: A Pilot Study

We investigated the associations between the self-evaluated pain status and two pain biomarker candidates, nerve growth factor and S100A8/A9, in exudate from venous leg ulcer to finally develop an objective pain evaluation method. Patients with venous leg ulcer participated in this cross-sectional observational study conducted between April and October 2014 at two medical facilities. During routine wound care, each participant self-evaluated their pain status at each examination using the 10-point numerical rating scale (present pain intensity) and the short-form McGill Pain Questionnaire 2 (continuous pain, intermittent pain, neuropathic pain, affective descriptors, and total score). Venous leg ulcer exudate sample was collected after wound cleansing. The nerve growth factor and S100A8/A9 concentrations in the venous leg ulcer exudate were measured by enzyme-linked immunosorbent assay and standardized according to the wound area. The association between each pain status and the two standardized protein concentrations was evaluated using Spearman’s correlation coefficient. In 30 sample collected from 13 participants, the standardized nerve growth factor concentration was negatively correlated with continuous pain (ρ = -0.47, P = 0.01), intermittent pain (ρ = -0.48, P = 0.01), neuropathic pain (ρ = -0.51, P = 0.01), and total score (ρ = -0.46, P = 0.01). The standardized S100A8/A9 concentration was positively correlated with present pain intensity (ρ = 0.46, P = 0.03) and continuous pain (ρ = 0.48, P = 0.03). Thus, these two proteins may be useful for objective evaluation of wound pain in venous leg ulcer patients.

Anti-atherosclerotic plants which modulate the phenotype of vascular smooth muscle cells

BACKGROUND

Cardiovascular disease (CVD) remains the leading cause of global death, with atherosclerosis being a major contributor to this mortality. Several mechanisms are implicated in the pathogenesis of this disease. A key element in the development and progression of atherosclerotic lesions is the phenotype of vascular smooth muscle cells. Under pathophysiologic conditions such as injury, these cells switch from a contractile to a synthetic phenotype that often possesses high proliferative and migratory capacities.

PURPOSE

Despite major advances made in the management and treatment of atherosclerosis, mortality associated with this disease remains high. This mandates that other approaches be sought. Herbal medicine, especially for the treatment of CVD, has been gaining more attention in recent years. This is in no small part due to the evidence-based values associated with the consumption of many plants as well as the relatively cheaper prices, easier access and conventional folk medicine "inherited" over generations. Sections: In this review, we provide a brief introduction about the pathogenesis of atherosclerosis then we highlight the role of vascular smooth muscle cells in this disease, especially when a phenotypic switch of these cells arises. We then thoroughly discuss the various plants that show potentially beneficial effects as anti-atherosclerotic, with prime attention given to herbs and plants that inhibit the phenotypic switch of vascular smooth muscle cells.

CONCLUSION

Accumulating evidence provides the justification for the use of botanicals in the treatment or prevention of atherosclerosis. However, further studies, especially clinical ones, are warranted to better define several pharmacological parameters of these herbs, such as toxicity, tolerability, and efficacy.

Electroacupuncture alleviates nerve injury after cerebra ischemia in rats through inhibiting cell apoptosis and changing the balance of MMP-9/TIMP-1 expression

Accumulating evidence demonstrates that acupuncture and electroacupuncture (EA) can exert a neuroprotective role for cerebral ischemia, but their precise mechanism remains largely unknown. Therefore, in this study, the effects of EA stimulation on cerebral ischemia reperfusion and its neuroprotective mechanisms were investigated. A rat model of middle cerebral artery occlusion (MCAO) was developed, and EA stimulation (2Hz, 1mA) at Baihui and Siguan acupoints was applied 30min after MCAO and then once daily for 7 consecutive days. The results indicated that EA stimulation significantly reduced the cerebral infarct area and neurological deficit scores, decreased the number of apoptotic cells, up-regulated Bcl-2 protein expression, and down-regulated Bax protein expression. EA stimulation resulted in a significant increase of proliferative cells in the cerebral tissues. Additionally, EA stimulation significantly down-regulated the expression levels of matrix metalloproteinase -9 (MMP-9) mRNA and protein, and simultaneously up-regulated the expression levels of tissue inhibitor of metalloproteinases-1 (TIMP-1) mRNA and protein, which resulted in an imbalance of MMP-9/TIMP-1expression, although it did not significantly change MMP-2 and TIMP-2 expression. These findings indicate that EA stimulation at Baihui and Siguan acupoints exerts a neuroprotective role against cerebral ischemia-reperfusion injury, which is probably associated with the inhibition of apoptosis and altering the balance of MMP-9/TIMP-1 expression.

Nerve growth factor facilitates perivascular innervation in neovasculatures of mice

It is well known that blood vessels including arterioles have a perivascular innervation. It is also widely accepted that perivascular nerves maintain vascular tone and regulate blood flow. Although there are currently prevailing opinions, unified views on the innervation of microcirculation in any organs have not been established. The present study was designed to investigate whether there are perivascular nerves innervated in microvessels and neovessels. Furthermore, we examined whether nerve growth factor (NGF) can exert a promotional effect on perivascular nerve innervation in neovessels of Matrigel plugs. A Matrigel was subcutaneously implanted in mouse. The presence of perivascular nerves in Matrigel on Day 7-21 after the implantation was immunohistochemically studied. NGF or saline was subcutaneously administered by an osmotic mini-pump for a period of 3-14 days. The immunostaining of neovasculatures in Matrigel showed the presence of perivascular nerves on Day 21 after Matrigel injection. Perivascular nerve innervation of neovessels within Matrigel implanted in NGF-treated mice was observed in Day 17 after Matrigel implantation. However, NGF treatment did not increase numbers of neovessels in Matrigel. These results suggest that perivascular nerves innervate neovessels as neovasculatures mature and that NGF accelerates the innervation of perivascular nerves in neovessels.

Cardiac Nerve Growth Factor Overexpression Induces Bone Marrow-derived Progenitor Cells Mobilization and Homing to the Infarcted Heart

Reparative response by bone marrow (BM)-derived progenitor cells (PCs) to ischemia is a multistep process that comprises the detachment from the BM endosteal niche through activation of osteoclasts and proteolytic enzymes (such as matrix metalloproteinases (MMPs)), mobilization to the circulation, and homing to the injured tissue. We previously showed that intramyocardial nerve growth factor gene transfer (NGF-GT) promotes cardiac repair following myocardial infarction (MI) in mice. Here, we investigate the impact of cardiac NGF-GT on postinfarction BM-derived PCs mobilization and homing at different time points after adenovirus-mediated NGF-GT in mice. Immunohistochemistry and flow cytometry newly illustrate the temporal profile of osteoclast and activation of MMP9, PCs expansion in the BM, and liberation/homing to the injured myocardium. NGF-GT amplified these responses and increased the BM levels of active osteoclasts and MMP9, which were not observed in MMP9-deficient mice. Taken together, our results suggest a novel role for NGF in BM-derived PCs mobilization/homing following MI.

Vascular function and brain-derived neurotrophic factor: The functional capacity factor

Brain-derived neurotrophic factor (BDNF) is essential for neurocognitive function. This study aims at establishing a plausible link between level of serum BDNF, functional capacity (FC), and vascular function in 181 young (age 25.5±9.1 years old), apparently healthy adults. Fasting blood samples were drawn from participants' antecubital veins into plain glass tubes while they were in a sitting position to evaluate serum BDNF using enzyme-linked immunosorbent assay (ELISA). Mercury-in-silastic strain-gauge plethysmography was used to determine arterial function indices, blood flow and vascular resistance at rest and following 5 minutes of arterial ischemia. The 6-minute walk distance (6MWD) test was used to determine FC, according to the American Thoracic Society Committee on Proficiency Standards for Clinical Pulmonary Function Laboratories guidelines. It was conducted in an enclosed corridor on a flat surface with a circular track 33 meters long. The walking course was demarcated with bright colored cones. The 6MWD correlated with BDNF (r=0.3, p=0.000), as well as with forearm blood inflow (r=0.5, p=0.000) and vascular resistance (r = -0.4, p=0.000). Subsequent comparison showed that BDNF and blood inflow were greater (p<0.05) while vascular resistance was less (p<0.05) in participants who achieved a longer 6MWD. Similarly, BDNF correlated with forearm blood inflow (r=0.4, p=0.000) and vascular resistance (r = -0.4, p=0.000). Subsequent comparison showed improved vascular function (p<0.05) in the participants with greater BDNF. In conclusion, these findings might suggest that improved vascular function in individuals with greater FC is mediated, at least partially, by an enhanced serum BDNF level.

EPO gene expression promotes proliferation, migration and invasion via the p38MAPK/AP-1/MMP-9 pathway by p21WAF1 expression in vascular smooth muscle cells

The use of recombinant human erythropoietin (rHuEpo) can lead to hypertrophy and hyperplasia, and has induced the proliferation of vascular smooth muscle cells (VSMCs). The effect of the EPO gene in the migration and invasion of VSMCs remains unclear. In this study, overexpression of the EPO gene increased the DNA synthesis and phosphorylation of ERK1/2 and p38MAPK in VSMCs. In addition, EPO gene expression induced the migration and invasion of VSMCs via the expression of MMP-9 by the activation of NF-κB and AP-1 binding. A blockade of p38MAPK by specific p38MAPK inhibitor SB203580 led to a suppression of the increased DNA synthesis, migration, and invasion of VSMCs that was induced by the EPO gene. SB203580 treatment blocked the increased expression of MMP-9 through the binding activity of AP-1. Transfection of the EPO gene with VSMCs was associated with the up-regulation of cyclin D1/CDK4, cyclin E/CDK2, and p21WAF1, and with the down-regulation of p27KIP1. The specific suppression of p21WAF1 expression by siRNA rescued the enhancement of DNA synthesis via the phosphorylation of p38MAPK and the increase in migration and invasion through AP-1-mediated MMP-9 expression in EPO gene transfectants. These novel findings demonstrate that p21WAF1 regulates the proliferation, migration and invasion of VSMC induced by EPO gene.

Nerve growth factor increases MMP9 activity in annulus fibrosus cells by upregulating lipocalin 2 expression

PURPOSE

Nerve growth factor (NGF) expression and activity is important in chronic lower back pain but may also act as a pro-catabolic factor in the pathogenesis of intervertebral disc (IVD) degeneration. Lipocalin 2 (Lcn2) expression in IVD was upregulated by NGF stimulation in our previous study. The current study was undertaken to identify potential mechanisms of the latter effect including potential interactions between Lcn2 and matrix metalloproteinase 9 (MMP9).

METHODS

Rat annulus fibrosus (AF) cells were stimulated by NGF and subjected to microarray analysis, subsequent real-time PCR, western immunoblotting, and immunofluorescence. Cells were treated with NGF in the absence or presence of the NGF inhibitor Ro 08-2750. Zymography and functional MMP9 assays were used to determine MMP9 activity, whilst the dimethyl-methylene blue assay was used to quantify the release of glycosaminoglycans (GAGs) reflecting catabolic effects following NGF treatment. Immunoprecipitation with immunoblotting was used to identify interactions between MMP9 and Lcn2.

RESULTS

Increased expression of Lcn2 gene and protein following NGF stimulation was confirmed by microarray analysis, real-time PCR, western blot and immunofluorescence. Zymography showed that NGF enhanced 125-kDa gelatinase activity, identified as a Lcn2/MMP9 complex by immunoprecipitation and immunoblotting. Functional assays showed increased MMP9 activity and GAG release in the presence of NGF. The effects of NGF were neutralized by the presence of Ro 08-2750.

CONCLUSIONS

NGF upregulates Lcn2 expression and increases MMP9 activity in AF cells; processes which are likely to potentiate degeneration of AF tissue in vivo. Anti-NGF treatment may have benefit for management of pain relief and slowing down progression of AF tissue degeneration.

Nerve growth factor promotes expression of novel genes in intervertebral disc cells that regulate tissue degradation

Object

Increased neurotrophin activity in degenerative intervertebral discs (IVDs) is one potential cause of chronic low-back pain (LBP). The aim of the study was to assess if nerve growth factor (NGF) might alter gene expression of IVD cells and contribute to disc degeneration by enhancing expression or activity of factors that cause breakdown of IVD matrix.

Methods

Rat-tail IVD cells were stimulated by NGF and subjected to microarray analysis. Real-time polymerase chain reaction, Western blotting, and immunocytochemistry of rat and human IVD cells and tissues treated with NGF in vitro in the absence or presence of the NGF inhibitor Ro 08-2750 were used to confirm findings of the microarray studies. Phosphorylation of mitogen-activated protein kinase (MAPK) was used to identify cell signaling pathways involved in NGF stimulation in the absence or presence of Ro 08-2750.

Results

Microarray analysis demonstrated increased expression of chitinase 3-like 1 (Chi3l1), lipocalin 2 (Lcn2), and matrix metalloproteinase–3 (Mmp3) following NGF stimulation of rat IVD cells in vitro. Increased gene expression was confirmed by real-time polymerase chain reaction with a relative increase in the Mmp/Timp ratio. Increased expression of Chi3l1, Lcn2, and Mmp3 following NGF stimulation was also demonstrated in rat cells and human tissue in vitro. Effects of NGF on protein expression were blocked by an NGF inhibitor and appear to function through the extracellular-regulation kinase 1/2 (ERK1/2) MAPK pathway.

Conclusions

Nerve growth factor has potential effects on matrix turnover activity and influences the catabolic/anabolic balance of IVD cells in an adverse way that may potentiate IVD degeneration. Anti-NGF treatment might be beneficial to ameliorate progressive tissue breakdown in IVD degeneration and may lead to pain relief.

Tumor necrosis factor-α regulates matrix metalloproteinase-2 expression and cell migration via ERK pathway in rat glomerular mesangial cells

Mesangial cells (MCs), vascular smooth muscle-derived cells, contribute to glomerular injury by generating a number of cytokines such as tumor necrosis factor-α (TNF-α). Matrix metalloproteinases (MMPs), regulated by various stimuli, are important in remodeling of glomerular ECM, which leads to a number of renal diseases. We investigated whether TNF-α participated in the regulation of MMPs and explored signal pathways involved in TNF-α-induced MMPs expression in rat glomerular MCs. Western blot and RT-qPCR results showed that treatment with TNF-α significantly increased the expression of MMP-2, but not MMP-9 at both protein and mRNA levels in rat glomerular MCs. The extracellular signal-regulated kinase (ERK) and nuclear factor-kappaB (NF-κB) signal pathways were activated by TNF-α. Moreover, the activation of NF-κB pathway in rat MCs was effectively inhibited by PD98059, specific inhibitor of ERK, suggesting a role for ERK in regulating NF-κB function. PD98059 or NF-κB signal pathway selective inhibitor Bay 11-7082 effectively blocked TNF-α-induced expression of MMP-2 in rat MCs, as determined by gene and protein expression. C-jun N-terminal kinase (JNK) signal pathway had no effect on TNF-α-induced expression of MMP-2, even though it was also activated by TNF-α in rat MCs. Furthermore, TNF-α could induce the cell migration of rat MCs, whereas ERK signal pathway specific inhibitor PD98059 compromised the cell migration triggered by TNF-α. Thus, TNF-α upregulates the expression of MMP-2 via activation of ERK-dependent NF-κB pathway in rat MCs, which may contribute to the cell migration of rat MCs.

Nerve growth factor exacerbates allergic lung inflammation and airway remodeling in a rat model of chronic asthma

Nerve growth factor (NGF) is critical in the pathogenesis of allergic airway inflammation in vivo and induces proliferation of airway smooth muscle cells and matrix metalloproteinase-9 (MMP-9) expression in vitro. However, the effects of NGF on chronic pulmonary diseases of allergic origin remain unknown. To investigate the effects of NGF on lung inflammation and airway remodeling, 32 Wistar rats were randomly divided into four groups: control, NGF, ovalbumin (OVA) and anti-rat-β-NGF antibody (anti-NGF). Aerosolized OVA was administered to the rats in the NGF, OVA and anti-NGF groups to generate the asthmatic rat model, and NGF or anti-NGF was administered 3 h prior to OVA inhalation every two days. On day 70, bronchial responsiveness tests, bronchoalveolar lavage (BAL) and cell counting were conducted. The levels of serum OVA-specific immunoglobulin E (IgE) and of T-helper cell type-2 (Th2) cytokines [interleukin (IL)-4 and IL-13] in the BAL fluid were measured by enzyme-linked immunosorbent assay. The expression levels of NGF protein and MMP-9 mRNA, and the activity of MMP-9 in the lungs were detected by western blot analysis, quantitative polymerase chain reaction and gelatin zymography analysis, respectively. Our results showed that NGF significantly increased eosinophilic airway inflammation, persistent airway hyperresponsiveness (AHR), the serum levels of OVA-specific IgE and the levels of Th2 cytokines in the BAL fluid, and also increased the expression levels and activity of MMP-9. However, anti-NGF treatment significantly inhibited eosinophilic airway inflammation, persistent AHR and airway remodeling. The results showed that NGF may have exacerbated the development of airway inflammation, AHR and airway remodeling through a Th2 pathway and by increasing the level of MMP-9 expression. Therefore, anti-NGF is potentially beneficial for preventing and treating patients with asthma.

Inhibition of endogenous NGF degradation induces mechanical allodynia and thermal hyperalgesia in rats

Background

We have previously shown a sprouting of sympathetic fibers into the upper dermis of the skin following subcutaneous injection of complete Freund’s adjuvant (CFA) into the hindpaw. This sprouting correlated with an increase in pain-related sensitivity. We hypothesized that this sprouting and pain-related behavior were caused by an increase in nerve growth factor (NGF) levels. In this study, we investigated whether the inhibition of mature NGF degradation, using a matrix metalloproteinase 2 and 9 (MMP-2/9) inhibitor, was sufficient to reproduce a similar phenotype.

Results

Behavioral tests performed on male Sprague–Dawley rats at 1, 3, 7 and 14 days after intra-plantar MMP-2/9 inhibitor administration demonstrated that acute and chronic injections of the MMP-2/9 inhibitor induced sensitization, in a dose dependent manner, to mechanical, hot and cold stimuli as measured by von Frey filaments, Hargreaves and acetone tests, respectively. Moreover, the protein levels of mature NGF (mNGF) were increased, whereas the levels and enzymatic activity of matrix metalloproteinase 9 were reduced in the glabrous skin of the hind paw. MMP-2/9 inhibition also led to a robust sprouting of sympathetic fibers into the upper dermis but there were no changes in the density of peptidergic nociceptive afferents.

Conclusions

These findings indicate that localized MMP-2/9 inhibition provokes a pattern of sensitization and fiber sprouting comparable to that previously obtained following CFA injection. Accordingly, the modulation of endogenous NGF levels should be considered as a potential therapeutic target for the management of inflammatory pain associated with arthritis.

Expression of nerve growth factor and matrix metallopeptidase-9/tissue inhibitor of metalloproteinase-1 in asthmatic patients

OBJECTIVE

The aim of this study was to measure the level of nerve growth factor (NGF) in bronchial specimens from humans and to determine whether it correlated with not only clinical characteristics of asthma such as percent eosinophils, Th2 cytokine levels, and pulmonary function, but also metallopeptidase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1).

METHODS

Fifty-three people participated; 42 had asthma. The participants underwent bronchoscopy and the specimens were analyzed. The participants' clinical data including pulmonary function tests were reviewed.

RESULTS

Bronchoalveolar lavage fluid (BALF) from patients with asthma had a significantly higher level of NGF compared with that from participants without asthma. NGF level showed a positive correlation with the percentage of eosinophils in both BALF and serum. The concentration of NGF did not correlate with that of Th2 cytokines interleukin (IL)-4, IL-5, and IL-13 in BALF or parameters of pulmonary function including degree of airway hyperresponsiveness (ARH). The levels of MMP-9 and TIMP-1 in BALF were higher in asthma patients than in participants without asthma. The levels of NGF correlated with TIMP-1 levels but not with MMP-9 in the whole participants.

CONCLUSIONS

This study shows that NGF correlates with levels of eosinophils, a major effector cell in asthma. The high expression of NGF and TIMP-1 in asthma patients and the moderate correlation between NGF and TIMP-1 in the entire group of asthma subjects suggest a possible association between NGF and TIMP-1, which may influence asthma pathogenesis.

Nerve growth factor promotes corneal epithelial migration by enhancing expression of matrix metalloprotease-9

PURPOSE

Nerve growth factor (NGF) is a neuropeptide essential for the development, survival, growth, and differentiation of corneal cells. Its effects are mediated by both TrkA and p75 receptors. Clinically relevant use of NGF was introduced to treat neurotrophic ulcerations in patients. Herein, we examine the mechanisms by which NGF enhances epithelial wound healing both in vivo and in vitro.

METHODS

An animal model using adult hens was implemented for the in vivo experiments. Laser ablation keratectomy was performed and animals were observed for up to 7 days. Epithelial healing was measured with fluorescein. In addition, proliferation was measured using BrdU incorporation and both TrkA and matrix metalloprotease-9 (MMP-9) expression were measured by immunohistochemistry (IHC) and Western blot (WB). In vitro experiments were carried out with telomerase-immortalized human corneal epithelial cells (HCLE). The rate of proliferation was measured using a colorimetric assay and BrdU incorporation. Real-time migration was evaluated with an inverted microscope. MMP-9 expression was evaluated by immunocytochemistry (ICC), WB, zymography, and RT-PCR. Finally, beta-4 integrin (β4) expression was assessed by ICC and WB.

RESULTS

Faster epithelial healing was observed in NGF-treated corneas compared with controls (P < 0.01). These corneas showed increased proliferation, TrkA upregulation, and enhanced MMP-9 presence (P < 0.01). In vitro, faster spreading and migration were observed in response to NGF (P < 0.01). Enhanced proliferation, as well as enhanced TrkA and MMP-9 expression, and decreased β4 levels were observed after adding NGF (P < 0.01).

CONCLUSIONS

NGF plays a major role during the epithelial healing process by promoting migration, a process that is accelerated by cell spreading. This effect is mediated by both the upregulation of MMP-9 and cleavage of β4 integrin.

Proprotein convertase furin enhances survival and migration of vascular smooth muscle cells via processing of pro-nerve growth factor

Maturation of nerve growth factor (NGF) in neuronal cells requires endoproteolytic processing of the precursor protein proNGF to β-NGF by the proprotein convertase furin. Pro- and β-NGF elicit opposite biological functions by differential neurotrophin-receptor binding, leading to apoptosis via sortilin or survival via neurotrophic tyrosine kinase receptor type-1 (TrkA), respectively. The present study was done to investigate the impact of furin-dependent proNGF processing on vascular smooth muscle cell (VSMC) function. We found that β-NGF mRNA and protein expression was upregulated in platelet-derived growth factor-BB/transforming growth factor-β1-stimulated, proliferating rat aortic VSMCs. Although β-NGF itself did not affect VSMC proliferation, it promoted VSMC motility in an autocrine fashion via TrkA/Akt-dependent integrin inside-out signalling. The β-NGF-induced migration of VSMCs required proNGF processing by furin, which was co-regulated with NGF. Furin-inhibition increased proNGF and reduced β-NGF secretion, leading to apoptosis rather than migration. In line with our in vitro demonstration, we found co- and upregulation of NGF, its convertase furin and its high-affinity receptor TrkA in the neointima of balloon-injured rodent arteries. These results indicate that furin determines the balance between proNGF and β-NGF in proliferating VSMCs, thus impacting on VSMC survival and migration and is also important in neointima formation.

Melittin has an inhibitory effect on TNF-α-induced migration of human aortic smooth muscle cells by blocking the MMP-9 expression

Matrix metalloproteinases-9 (MMP-9) plays an important role in the pathogenesis of atherosclerosis and migration of vascular smooth muscle cells (VSMCs) after an arterial injury. In this study, we investigated the potential molecular mechanisms underlying the anti-atheroscleroic effects of melittin, a major component of bee venom, in human aortic smooth muscle cells (HASMCs). Melttin significantly suppressed MMP-9 and MMP-2 secretion, as well as TNF-α-induced MMP-9 expression in the HASMCs. In addition, we found that the inhibitory effects of melittin on TNF-α-induced MMP-9 protein expression are associated with the inhibition of MMP-9 transcription levels. Mechanistically, Melittin suppressed TNF-α-induced MMP-9 activity by inhibiting the phosphorylation of p38 and ERK1/2, but did not affect the phosphorylation of JNK and Akt. Reporter gene and western blotting assays showed that melittin inhibits MMP-9 transcriptional activity by blocking the activation of NF-κB via IκBα signaling pathway. Moreover, the matrigel migration assay showed that melittin reduced TNF-α-induced HASMC migration. These results suggest that melittin suppresses TNF-α-induced HASMC migration through the selective inhibition of MMP-9 expression and provide a novel role of melittin in the anti-atherosclerotic action.

Pimaric acid from Aralia cordata has an inhibitory effect on TNF-α-induced MMP-9 production and HASMC migration via down-regulated NF-κB and AP-1

Many studies have indicated that activation of matrix metalloproteinase (MMP)-9 and smooth muscle cell (SMC) migration are involved in neointimal formation and atherosclerosis. In this study, we revealed that pimaric acid (PiMA) purified from Aralia cordata had an inhibitory effect on MMP-9 production and migration of human aortic smooth muscle cells (HASMCs) induced by tumor necrosis factor (TNF)-α. Down-regulated MMP-9 mRNA transcription was detected in PiMA-treated cells using RT-PCR and the luciferase-tagged MMP-9 promoter assay. Results of an electrophoretic mobility shift assay indicated that PiMA-treated HASMCs showed decreased binding activity of nuclear factor (NF)-κB and activator protein-1 transcription factors. A Western-blot analysis using nuclear extract demonstrated that PiMA reduced the levels of NF-κB p65, c-Fos, p-c-Jun, Jun-D, and p-ATF2 proteins in the nucleus. In addition, TNF-α stimulated mitogen activated protein kinase (MAPK) containing extracellular signal regulated kinase 1 and 2, p38, and c-Jun N-terminal kinase was inhibited by PiMA. Using the Transwell system, we found that PiMA inhibited TNF-α stimulated HASMC migration/invasion in a dose-dependent manner. To confirm whether MAPK mediated MMP-9 expression, we used MAPK inhibitors including U0126, SB253580, and SP600125 and found that those inhibitors reduced MMP-9 expression and HASMC migration/invasion. These results suggest that PiMA has potent anti-atherosclerotic activity with inhibitory action on MMP-9 production and cell migration in TNF-α-induced HASMCs.

Update on the Pathophysiological Role of Intracellular Signaling Pathways in Atherosclerotic Plaques and Ischemic Myocardium

Acute atherosclerotic complications, such as myocardial infarction, are often provoked by the rupture of an atherosclerotic plaque and the subsequent thrombotic occlusion of the arterial lumen, which interrupts the blood flow and renders ischemic the downstream peripheral tissue. Several inflammatory mediators (including cytokines, chemokines and matrix metalloproteases) have been shown to orchestrate common pathophysiological mechanisms regulating both plaque vulnerability and myocardial injury. In particular, the selective activation of certain protective intracellular signaling pathways might represent a promising target to reduce the dramatic consequences of an ischemic cardiac event. In the present review we will update evidence on the active role of intracellular kinase cascades (such as mitogen-activated protein kinases [MAPKs], Akt, Janus kinase [JAK]-signal transducer and activator of transcription [STAT]) to reduce the global patient vulnerability for acute myocardial infarction.

Laminin induces matrix metalloproteinase-9 expression and activation in human cervical cancer cell line (SiHa)

PURPOSE

Interaction between cell surface integrin receptors and extracellular matrix (ECM) components plays an important role in cell survival, proliferation and migration including tumor development and invasion. Matrix metalloproteinases (MMP) are a family of metalloproteinases capable of digesting ECM and facilitate cell migration. Binding of ECM to integrins initiates signaling cascades modulating expression and activity of different MMPs. The present study investigates whether laminin-mediated signaling modulates matrix metalloproteinases (MMP) expression and activity in human cervical cancer cell (SiHa).

METHODS

Western blot, immunocytochemistry, ELISA, zymography, RT-PCR, EMSA and wound-healing assay were used.

RESULTS

Culture of SiHa cells on laminin (LN)-coated surface induces MMP-9 expression and activation. Wound-healing assay showed that SiHa cells migrate much faster on laminin-coated surface than that of control. LN-induced MMP-9 expression and activation was appreciably reduced with treatment of extracellular signal-regulated kinase (ERK) inhibitor, phosphatidylinositol-3-kinase (PI-3K) inhibitor and anti-α2 antibody. Phosphorylation of focal adhesion kinase (FAK), ERK, and PI-3K was increased upon LN stimulation. LN induces nuclear translocation of PI-3K and nuclear factor kappa B (NF-κB). LN increases DNA-binding activity of NF-κB and activator protein-1 (AP-1) to MMP-9 promoter.

CONCLUSIONS

Our findings indicate laminin-induced MMP-9 expression and activation possibly via α2β1 integrin-mediated signaling involving FAK, PI-3K, ERK followed by transcriptional upregulation of MMP-9.

Cardiovascular actions of neurotrophins

Neurotrophins were christened in consideration of their actions on the nervous system and, for a long time, they were the exclusive interest of neuroscientists. However, more recently, this family of proteins has been shown to possess essential cardiovascular functions. During cardiovascular development, neurotrophins and their receptors are essential factors in the formation of the heart and critical regulator of vascular development. Postnatally, neurotrophins control the survival of endothelial cells, vascular smooth muscle cells, and cardiomyocytes and regulate angiogenesis and vasculogenesis, by autocrine and paracrine mechanisms. Recent studies suggest the capacity of neurotrophins, via their tropomyosin-kinase receptors, to promote therapeutic neovascularization in animal models of hindlimb ischemia. Conversely, the neurotrophin low-affinity p75(NTR) receptor induces apoptosis of endothelial cells and vascular smooth muscle cells and impairs angiogenesis. Finally, nerve growth factor looks particularly promising in treating microvascular complications of diabetes or reducing cardiomyocyte apoptosis in the infarcted heart. These seminal discoveries have fuelled basic and translational research and thus opened a new field of investigation in cardiovascular medicine and therapeutics. Here, we review recent progress on the molecular signaling and roles played by neurotrophins in cardiovascular development, function, and pathology, and we discuss therapeutic potential of strategies based on neurotrophin manipulation.

Expression of matrix metalloproteinase 2 and 9 in experimentally wounded canine corneas and spontaneous chronic corneal epithelial defects

PURPOSE

To determine matrix metalloproteinase (MMP) 2 and MMP 9 expression in acute and chronic experimentally wounded canine corneas and keratectomy samples from canine patients with spontaneous chronic corneal epithelial defects (SCCEDs).

METHODS

Mechanical debridement was performed unilaterally in 25 healthy dogs for the acute wound study. Twenty-four hours (n = 8), 48 hours (n = 5), 72 hours (n = 3), or 1 week (n = 9) after wounding, the dogs were euthanized. Debridement was performed once weekly for 8 weeks for the chronic study (n = 8). Therapeutic superficial keratectomies (n = 16) were performed on SCCED patients. Gelatin zymography and immunohistochemistry were performed.

RESULTS

Acute wounds showed upregulation of MMP 9 at all time points. At 7 days after wounding, values diminished markedly but remained elevated above those of unwounded controls. SCCED and chronic wound samples showed a significant increase in MMP 9 compared with controls but were less than that of acute wounds. There was no significant difference between chronic wounds versus SCCED samples. Fellow control eyes showed significant upregulation of MMP 9 in tandem with wounded eyes. There was no significant difference in values for MMP 2 in wounded corneas or SCCED compared with those of controls. Immunhistochemistry localized MMP 9 to predominantly the epithelium with some staining of keratinocytes and stroma.

CONCLUSIONS

The dog exhibits similar MMP expression during corneal wound healing to that of other species. The lack of significant difference in MMP expression between SCCED and chronic wounds suggest that MMP 2 and 9 are not involved in the pathophysiology of SCCED and are more likely altered secondary to a chronic epithelial defect.

Effects of neurotrophins on human bronchial smooth muscle cell migration and matrix metalloproteinase-9 secretion

The neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) have been found to be upregulated in inflammatory pulmonary diseases, including asthma. The functional role for the neurotrophins in the airways is still not known, but it has been proposed that neurotrophins induce airway hyperreactivity and tissue remodeling. Bronchial smooth muscle cells have been suggested to be involved in the remodeling process through their capacity to proliferate, migrate, and secrete inflammatory mediators and matrix metalloproteinases (MMPs). Therefore, we studied the effect of NGF, BDNF, and NT-3 on human bronchial smooth muscle cell (HBSMC) migration and MMP-2 and MMP-9 secretion. Immunocytochemistry studies showed that HBSMCs expressed the neurotrophin receptors TrkA, TrkB, and TrkC. BDNF, NT-3, and NGF increased MMP-9, but not MMP-2, secretion as shown by zymography. BDNF and NT-3, but not NGF, stimulated HBSMC migration as evaluated by Boyden chamber. Taken together, our data indicate that the neurotrophins may stimulate events important for airway remodeling.

The role of ERK signaling in protein hydrogel remodeling by vascular smooth muscle cells

Collagen type I and fibrin hydrogels have been used for cell-based therapies and tissue engineering. These matrices can be broken down and remodeled by cells, but the effects that these proteins have on cell function are not completely understood. We examined activation of the extracellular signal-regulated kinase (ERK) signaling pathway by vascular smooth muscle cells (VSMC) in response to 2D and 3D matrices of type I collagen, fibrin, or a 1:1 composite mixture of these proteins. After 3 days of culture, ERK phosphorylation, osteopontin secretion, and MMP-2 activation were all markedly increased in 3D matrices, compared with 2D substrates. A strong positive correlation existed between these protein markers of the synthetic phenotype and phosphorylated ERK levels, and this relationship persisted across matrix geometries and compositions. Cell proliferation in 3D matrices was inversely correlated to ERK activation, while on 2D substrates a modest positive correlation was observed. Pharmacologic inhibition of ERK signaling confirmed that this pathway was involved in the observed phenotype shifts. This study suggests that contextual activation of the ERK pathway results in different effects on cell phenotype, depending on the geometry and composition of the ECM. These findings add to our understanding of cell function and remodeling in protein-based hydrogel biomaterials.

Salvianolic acid B attenuates MMP-2 and MMP-9 expression in vivo in apolipoprotein-E-deficient mouse aorta and in vitro in LPS-treated human aortic smooth muscle cells

Salvianolic acid B (Sal B), a water-soluble antioxidant derived from a Chinese medicinal herb, is believed to have multiple therapeutic and preventive against human vascular diseases, including atherosclerosis and restenosis. To elucidate the underlying cellular mechanisms, we produced hypercholesterolemia by feeding apo-E-deficient mice a 0.15% cholesterol diet and inflammation in human aortic smooth muscle cells (HASMCs) with the endotoxin lipopolysaccharide (LPS), focusing on the metallopreteinases MMP-2 and MMP-9, the relevant signal transduction pathways and the effects of Sal B. Immunohistochemical analyses indicated apo-E-deficient mice fed a 0.15% cholesterol diet for 12 weeks exhibited thickened intima and elevated levels of MMP-2 and MMP-9 in aortic sections, both of which were attenuated by 0.3% Sal B dietary supplement. Western blotting and zymography analyses indicated that unstimulated HASMCs exhibited basal levels of protein and activity levels for MMP-2 and barely detectable levels for MMP-9, both of which were markedly upregulated by LPS, which also induced cell migration. Sal B significantly attenuated upregulations of both MMPs as well as the LPS-induced cell migration through the inactivation of MMP-2 and MMP-9 protein synthesis as well as the downregulation of the extracellular-signal-regulated kinase 1/2 (ERK1/2) and c-Jun NH(2)-terminal kinase (JNK). These results demonstrate that Sal B has anti-migration properties on smooth muscle cells and may explain its anti-atherosclerotic properties. This novel mechanism of action of Sal B, in addition to its previously reported inhibition of LDL oxidation, may help explain its efficacy in the treatment of atherosclerosis.

Matrix metalloproteinases and proteoglycans in axonal regeneration

After an injury to the adult mammalian central nervous system (CNS), a variety of growth-inhibitory molecules are upregulated. A glial scar forms at the site of injury and is composed of numerous molecular substances, including chondroitin sulfate proteoglycans (CSPGs). These proteoglycans inhibit axonal growth in vitro and in vivo. Matrix metalloproteinases (MMPs) can degrade the core protein of some CSPGs as well as other growth-inhibitory molecules such as Nogo and tenascin-C. MMPs have been shown to facilitate axonal regeneration in the adult mammalian peripheral nervous system (PNS). This review will focus on the various roles of proteoglycans and MMPs within the injured nervous system. First, we will present a general background on the injured central nervous system and explore the roles that proteoglycans play in the injured PNS and CNS. Second, we will discuss the various functions of MMPs within the injured PNS and CNS. Special attention will be paid to the possibility of how MMPs might modify the growth-inhibitory extracellular environment of the injured adult mammalian spinal cord and facilitate axonal regeneration in the CNS.

Cryptotanshinone from Salvia miltiorrhiza BUNGE has an inhibitory effect on TNF-α-induced matrix metalloproteinase-9 production and HASMC migration via down-regulated NF-κB and AP-1

Matrix metalloproteinases (MMP-9 and MMP-2) production and smooth muscle cell (SMC) migration may play key roles in the phathogenesis of neointima formation and atherosclerosis. Especially inducible MMP-9 expression was directly involved in the cancer cell invasion and SMC migration through vascular wall. In this study, we reveal that cryptotanshinone (CT) purified from Salvia miltiorrhiza BUNGE had an inhibitory effect on MMP-9 production and migration of human aortic smooth muscle cells treated with TNF-alpha in a dose-dependent manner. The down regulation of transcription of MMP-9 mRNA was evidenced by RT-PCR and MMP-9 promoter assay using luciferase reporter gene. Eletrophoretic mobility shift assay showed NF-kappaB and AP-1 nuclear translocations were suppressed. In addition, Western blot analysis indicated that extracellular signal regulated kinase 1 and 2, p38 and JNK MAP kinase signaling pathways were inhibited. From the results, it is suggested that CT has anti-atherosclerosis and anti-neointimal formation activity.

Nerve growth factor effect on human primary fibroblastic-keratocytes: Possible mechanism during corneal healing

In response to corneal injury, cytokines and growth factors play a crucial role by influencing epithelial-stromal interaction during the healing and reparative processes which may resolve in tissue remodeling and fibrosis. While transforming growth factor-beta1 (TGF-beta1) is considered the main profibrogenic modulator of these process, recently the nerve growth factor (NGF) appears as a pleiotropic modulator of wound-healing and inflammatory responses. Interestingly in the cornea, where NGF, trkA(NGFR) and p75(NTR) are expressed by epithelial cells and keratocytes, the NGF eye-drop induces the healing of neurotrophic or autoimmune corneal ulcers. During corneal healing, quiescent keratocytes are replaced by active fibroblast-like keratocytes/myofibroblasts. While the NGF effect on epithelial cells has been investigated, no data are reported for NGF effects on fibroblastic-keratocytes, during corneal healing. NGF, trkA(NGFR) and p75(NTR) were found expressed by fibroblastic-keratocytes. NGF was able to induce fibroblastic-keratocyte differentiation into myofibroblasts, migration, Metalloproteinase-9 expression/activity and contraction of a 3D collagen gel, without affecting their proliferation and collagen production. These data also show a two-directional control of fibroblastic-keratocytes by NGF and TGF-beta1. To sum up, the findings of this study indicate that NGF can modulate some functional activities of fibroblastic-keratocytes, thus substantiating the healing effects of NGF on corneal wound-healing.

Neurotrophins in allergic diseases: From neuronal growth factors to intercellular signaling molecules

Understanding the complex pathophysiology of allergic diseases has been a main challenge of clinical and experimental research for many years. It is well known that the allergic inflammation triggers neuronal dysfunction and structural changes in the diseased tissues such as the airways or the skin. Recent evidence has emerged that the inflammatory response is also controlled by resident tissue cells such as neurons and structural cells. Therefore, signaling molecules that mediate inflammatory interactions among immune, neuronal, and structural cells are becoming a focus of allergy research. Neurotrophins, a family of homologous growth factors initially discovered in the nervous system, display such bidirectional signaling. The expression of neurotrophins, such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), is highly upregulated during allergic inflammation. Neurons, structural cells, and invading immune cells were now identified not only as sources but also as targets of neurotrophins within the inflamed tissue. In this review, we provide an actual overview of the role of neurotrophins in the pathobiology of allergic diseases. We discuss recent findings in human and animal studies such as the regulation of neurotrophin expression during allergic inflammation and the effect of neurotrophins on the development and magnitude of allergic reactions.

Decreased Neurotrophin TrkB Receptor Expression Reduces Lesion Size in the Apolipoprotein E–Null Mutant Mouse

Background— Accumulation of macrophages and smooth muscle cells in the vascular wall is critical for the development of atherosclerotic lesions. Although much is known about the factors that regulate macrophage recruitment to the vascular wall, the ability of growth factors to regulate smooth muscle cell recruitment in lesion development in vivo is unclear. Our previous studies demonstrated that neurotrophins and their receptors, the Trk receptor tyrosine kinases, are potent chemotactic factors for smooth muscle cells, and the expression of brain-derived neurotrophic factor (BDNF) and its cognate receptor, TrkB, is upregulated in human atherosclerotic lesions.

Methods and Results— TrkB +/− mice on a 129/B6 background were backcrossed to apolipoprotein E (ApoE)–null ( ApoE −/− ) mice on the C57Bl/6 background for 6 to 8 generations. Immunohistochemical analysis demonstrated BDNF immunoreactivity in areas of macrophage and smooth muscle cell infiltration, whereas TrkB immunoreactivity was predominant in areas of neointimal smooth muscle cells. Moreover, haplodeficient expression of TrkB in ApoE −/− mice was associated with a 30% to 40% reduction in lesion size compared with ApoE −/− mice with normal expression of TrkB and a 45% decrease in smooth muscle cell accumulation in the lesions. Finally, reconstitution with bone marrow from ApoE −/− mice with normal TrkB expression did not restore lesion development in TrKB +/− / ApoE −/− mice.

Conclusions— These results suggest that TrkB expression on smooth muscle cells contributes to lesion development in the cholesterol-fed ApoE–null mutant mouse. These data demonstrate, for the first time, a role for the neurotrophin TrkB receptor in atherosclerotic lesion development.

Neurotrophins promote revascularization by local recruitment of TrkB+ endothelial cells and systemic mobilization of hematopoietic progenitors

The neurotrophin brain-derived neurotrophic factor (BDNF) is required for the maintenance of cardiac vessel wall stability during embryonic development through direct angiogenic actions on endothelial cells expressing the tropomysin receptor kinase B (TrkB). However, the role of BDNF and a related neurotrophin ligand, neurotrophin-4 (NT-4), in the regulation of revascularization of the adult tissues is unknown. To study the potential angiogenic capacity of BDNF in mediating the neovascularization of ischemic and non-ischemic adult mouse tissues, we utilized a hindlimb ischemia and a subcutaneous Matrigel model. Recruitment of endothelial cells and promotion of channel formation within the Matrigel plug by BDNF and NT-4 was comparable to that induced by VEGF-A. The introduction of BDNF into non-ischemic ears or ischemic limbs induced neoangiogenesis, with a 2-fold increase in the capillary density. Remarkably, treatment with BDNF progressively increased blood flow in the ischemic limb over 21 days, similar to treatment with VEGF-A. The mechanism by which BDNF enhances capillary formation is mediated in part through local activation of the TrkB receptor and also by recruitment of Sca-1+CD11b+ pro-angiogenic hematopoietic cells. BDNF induces a potent direct chemokinetic action on subsets of marrow-derived Sca-1+ hematopoietic cells co-expressing TrkB. These studies suggest that local regional delivery of BDNF may provide a novel mechanism for inducing neoangiogenesis through both direct actions on local TrkB-expressing endothelial cells in skeletal muscle and recruitment of specific subsets of TrkB+ bone marrow-derived hematopoietic cells to provide peri-endothelial support for the newly formed vessels.

Neurotrophins promote revascularization by local recruitment of TrkB+ endothelial cells and systemic mobilization of hematopoietic progenitors

The neurotrophin brain-derived neurotrophic factor (BDNF) is required for the maintenance of cardiac vessel wall stability during embryonic development through direct angiogenic actions on endothelial cells expressing the tropomysin receptor kinase B (TrkB). However, the role of BDNF and a related neurotrophin ligand, neurotrophin-4 (NT-4), in the regulation of revascularization of the adult tissues is unknown. To study the potential angiogenic capacity of BDNF in mediating the neovascularization of ischemic and non-ischemic adult mouse tissues, we utilized a hindlimb ischemia and a subcutaneous Matrigel model. Recruitment of endothelial cells and promotion of channel formation within the Matrigel plug by BDNF and NT-4 was comparable to that induced by VEGF-A. The introduction of BDNF into non-ischemic ears or ischemic limbs induced neoangiogenesis, with a 2-fold increase in the capillary density. Remarkably, treatment with BDNF progressively increased blood flow in the ischemic limb over 21 days, similar to treatment with VEGF-A. The mechanism by which BDNF enhances capillary formation is mediated in part through local activation of the TrkB receptor and also by recruitment of Sca-1+CD11b+ pro-angiogenic hematopoietic cells. BDNF induces a potent direct chemokinetic action on subsets of marrow-derived Sca-1+ hematopoietic cells co-expressing TrkB. These studies suggest that local regional delivery of BDNF may provide a novel mechanism for inducing neoangiogenesis through both direct actions on local TrkB-expressing endothelial cells in skeletal muscle and recruitment of specific subsets of TrkB+ bone marrow-derived hematopoietic cells to provide peri-endothelial support for the newly formed vessels.

The role of matrix metalloproteinase 9 in the pathogenesis of chronic lymphocytic leukaemia

Matrix metalloproteinases (MMPs) are important for the pathogenesis and progression of different tumours. MMPs-2 and -9 are the principal MMPs produced by lymphocytes; these enzymes can degrade a number of matrix proteins but are the two main MMPs that digest type IV collagen, the major component of basement membranes. Therefore, these enzymes are potentially important for tissue invasion and remodelling by malignant lymphocytes. This study showed that chronic lymphocytic leukaemia (CLL) cells produce and secrete variable amounts of pro-MMP-9, but no MMP-2 or tissue inhibitor of metalloproteinase 1 (TIMP-1). The pro-enzyme was found in monomeric and dimeric forms and also complexed with lipocalin. Moreover, a small fraction of secreted monomer became associated with the cell surface and activated upon cell adhesion to insolubilized type IV collagen. High levels of intracellular MMP-9 were associated with advanced (stage C) disease and with poor patient survival. Immunohistochemical studies demonstrated that MMP-9 was associated with areas of tissue invasion and remodelling. The relatively specific MMP-9 inhibitors, Ro31-9790 (3 micromol/l) and TIMP-1, reduced CLL-cell migration through type IV collagen and through endothelial monolayers suggesting that the enzyme may also be important in malignant cell entry and egress to and from involved tissue. Our data raise the possibility that MMP-9 modulation may have therapeutic potential in advanced CLL.

Chemokine receptor–8 (CCR8) mediates human vascular smooth muscle cell chemotaxis and metalloproteinase-2 secretion

The response of the arterial vascular wall to injury is characterized by vascular smooth muscle cell (VSMC) migration, a process requiring metalloproteinase production. This migration is induced by cytokines, however the agonists involved are not fully defined. The CC chemokine receptor 8 (CCR8) is expressed on monocytes and T lymphocytes and is the sole receptor for the human CC chemokine 1 (CCL1, I-309) and for the viral chemokine, vCCL1 (viral macrophage inflammatory protein 1 [vMIP-1]). We have reported that CCR8 is expressed on human umbilical vein endothelial cells (HUVECs) and mediates chemotaxis induced by CCL1. The conditioned medium from incubation mixtures of lipoprotein(a) (Lp(a)) and HUVECs (LCM) contained CCL1 and stimulated both monocyte and HUVEC chemotaxis, providing novel mechanisms for the atherogenicity of Lp(a). We now report that CCL1, vCCL1, and LCM stimulate chemotaxis of human VSMCs that is blocked by murine monoclonal antibody against CCR8 and by the G-protein inhibitor pertussis toxin. The effect of anti-CCR8 was specific, as this antibody failed to effect the chemotaxis of VSMCs in response to CCL3 or by platelet-derived growth factor BB (PDGF-BB). VSMCs contained CCR8 mRNA and CCR8 antigen coprecipitated with VSMC membranes. Antibodies against metalloproteinase-2 (MMP-2) inhibited the CCL1-induced chemotaxis of VSMCs, whereas anti–MMP-9 was less effective. CCL1 induced VSMC pro–MMP-2 mRNA and protein secretion. Poxvirus MC148 inhibited the increase in MMP-2 induced by CCL1, documenting that CCR8 was the receptor responsible. In mouse femoral arteries, CCR8 and TCA3 antigen colocalized with VSMCs and were up-regulated after injury. The induction of CCR8 and CCL1/TCA3 under conditions associated with VSMC proliferation and migration raises the possibility that CCR8 may play an important role in vessel wall pathology.

ERK1/2 mediates TNF-?-induced matrix metalloproteinase-9 expression in human vascular smooth muscle cells via the regulation of NF-?B and AP-1: Involvement of the ras dependent pathway

The expression of matrix metalloproteinase-9 (MMP-9) has been implicated in progression of atherosclerotic lesions. The role and importance of the signaling pathway in the transcriptional regulation of MMP-9 in human aortic smooth muscle cells (HASMC) was examined. Tumor necrosis factor-alpha (TNF-alpha) stimulated the secretion of MMP-9 in HASMC, as shown by zymography and immunoblot analysis. At the transcriptional levels, TNF-alpha also stimulated the 5'-flanking 710-bp promoter activity of MMP-9. Transcription factors NF-kappaB binding site (-601) and AP-1 binding site (-82) were identified as the cis-elements for TNF-alpha activation, as determined by gel shift assay and mutation analysis. Treatment with U0126, an inhibitor of the extracellular signal-regulated kinase (ERK), significantly downregulated TNF-alpha-induced MMP-9 expression and promoter activity, whereas the inactive analog U0124 had no effect. Furthermore, the transactivation of TNF-alpha-stimulated NF-kappaB and AP-1 was inhibited by U0126 treatment. Finally, the transient transfection of HASMC with dominant negative Ras (RasN17) suppressed TNF-alpha-induced ERK activity, MMP-9 production, and promoter activity. Overexpression of RasN17 also abolished the TNF-alpha-stimulated NF-kappaB and AP-1 activity. In conclusion, the findings herein indicate the activation of the Ras/ERK pathway contributes to the induction of MMP-9 expression in HASMC. In addition, the transcription factors NF-kappaB and AP-1 that are involved in the Ras/ERK-mediated control of MMP-9 regulation on HASMC in response to TNF-alpha have now been identified.

Donor spontaneous intracerebral hemorrhage is associated with systemic activation of matrix metalloproteinase-2 and matrix metalloproteinase-9 and subsequent development of coronary vasculopathy in the heart transplant recipient

BACKGROUND

Matrix metalloproteinase (MMP)-2 and MMP-9 have been shown to play a role in the progression of hemorrhagic stroke. We hypothesized that donor intracerebral hemorrhage (ICH) is associated with activation of the metalloproteinases before transplantation that play a key role in the subsequent development of transplant vasculopathy.

METHODS AND RESULTS

We evaluated mRNA expressions of MMP-2 and MMP-9 in donor spleen lymphocytes (before transplantation) and in heart biopsies at 1 week after transplantation in 20 recipients from ICH donors and 20 recipients from trauma donors. Patients underwent serial coronary intravascular ultrasound, and interstitial myocardial fibrosis was quantified at 1 year. The baseline characteristics were similar except for increased donor age in the ICH group. Heart biopsies from the ICH group showed significant increased expression of MMP-2 (17-fold, P<0.0001) and MMP-9 (20-fold, P<0.0001) compared with the trauma group. Furthermore, the ICH group showed 1.8-fold (P=0.016) increased mRNA expression of MMP-2 and 1.7-fold (P=0.015) increased mRNA expression of MMP-9 in the donor spleen lymphocytes, suggesting the presence of systemic activation of metalloproteinases before transplantation. At 1 year, the ICH group showed increased myocardial fibrosis and accelerated coronary vasculopathy. Using multivariate regression analysis, MMP-9 was found to be associated with increased risk for vasculopathy independent of donor age (OR, 2.41; P=0.01; 95% CI, 1.24 to 4.69).

CONCLUSIONS

This is the first report to describe systemic activation of MMP-2 and MMP-9 in donors with intracerebral hemorrhage and subsequent development of allograft vasculopathy.