CCR7 Mediates Cell Invasion and Migration in Extrahepatic Cholangiocarcinoma by Inducing Epithelial-Mesenchymal Transition.

The epithelial-mesenchymal transition (EMT) contributes to the metastatic cascade in various tumors. C-C chemokine receptor 7 (CCR7) interacts with its ligand, chemokine (C-C motif) ligand 19 (CCL19), to promote EMT. However, the association between EMT and CCR7 in extrahepatic cholangiocarcinoma (EHCC) remains unknown. This study aimed to elucidate the prognostic impact of CCR7 expression and its association with clinicopathological features and EMT in EHCC. The association between CCR7 expression and clinicopathological features and EMT status was examined via the immunohistochemical staining of tumor sections from 181 patients with perihilar cholangiocarcinoma. This association was then investigated in TFK-1 and EGI-1 EHCC cell lines. High-grade CCR7 expression was significantly associated with a large number of tumor buds, low E-cadherin expression, and poor overall survival. TFK-1 showed CCR7 expression, and Western blotting revealed E-cadherin downregulation and vimentin upregulation in response to CCL19 treatment. The wound healing and Transwell invasion assays revealed that the activation of CCR7 by CCL19 enhanced the migration and invasion of TFK-1 cells, which were abrogated by a CCR7 antagonist. These results suggest that a high CCR7 expression is associated with an adverse postoperative prognosis via EMT induction and that CCR7 may be a potential target for adjuvant therapy in EHCC.

Ligand binding to human prostaglandin E receptor EP4 at the lipid-bilayer interface.

Prostaglandin E receptor EP4, a G-protein-coupled receptor, is involved in disorders such as cancer and autoimmune disease. Here, we report the crystal structure of human EP4 in complex with its antagonist ONO-AE3-208 and an inhibitory antibody at 3.2 Å resolution. The structure reveals that the extracellular surface is occluded by the extracellular loops and that the antagonist lies at the interface with the lipid bilayer, proximal to the highly conserved Arg316 residue in the seventh transmembrane domain. Functional and docking studies demonstrate that the natural agonist PGE2 binds in a similar manner. This structural information also provides insight into the ligand entry pathway from the membrane bilayer to the EP4 binding pocket. Furthermore, the structure reveals that the antibody allosterically affects the ligand binding of EP4. These results should facilitate the design of new therapeutic drugs targeting both orthosteric and allosteric sites in this receptor family.

Impaired post-infarction cardiac remodeling in chronic kidney disease is due to excessive renin release.

The complex pathophysiological interactions between heart and kidney diseases are collectively known as cardiorenal syndrome. The renin-angiotensin system (RAS) may have a pivotal role in the development of cardiorenal syndrome. The aim of this study was to elucidate the RAS activity responsible for adverse post-infarction remodeling and prognosis in mice with renal failure. To establish the type IV cardiorenal syndrome model, 5/6 nephrectomy (NTX) was performed in a surgical procedure, followed by the induction of myocardial ischemia (MI) by a coronary artery ligation 4 weeks later. NTX and MI resulted in deteriorated left ventricular remodeling and RAS activation, which was improved by an aliskiren that appeared to be independent of renal function and blood pressure (BP). Moreover, MI induced in renin and angiotensinogen double-transgenic (Tg) mice showed comparable effects to MI plus NTX mice, including advanced ventricular remodeling and enhancement of RAS, oxidative stress, and monocytes chemoattractant protein (MCP)-1. Aliskiren suppressed these changes in the MI-induced Tg mice. In in vitro study, Nox2 expression was elevated by the stimulation of plasma from NTX mice in isolated neonatal cardiomyocytes. However, Nox2 upregulation was negated when we administered plasma from aliskiren-treated-NTX mice or isolated cardiomyocytes from AT1-deficient mice. Primary mononuclear cells also showed an upregulation in the expression of Nox2 and MCP-1 by stimulation with plasma from NTX mice. Our data suggest that renal disorder results in ventricular dysfunction and deteriorates remodeling after MI through excessive RAS activation. Moreover, renin inhibition improved the changes caused by cardiorenal syndrome.

Different roles of PPAR-γ activity on physiological and pathological alteration after myocardial ischemia.

BACKGROUND: Telmisartan is an angiotensin II receptor blocker, which acts as a partial agonist of peroxisome proliferator activator receptor-γ (PPAR-γ). Because PPAR-γ initiates a variety of antiinflammatory responses, the effect on myocardial ischemia is to be elucidated. METHODS AND RESULTS: The left anterior descending arteries were ligated to induce myocardial infarction in rats. The animals were assigned to 4 groups: (1) control (saline, n = 6), (2) telmisartan (10 mg·kg·d, n = 6), (3) telmisartan + GW9662 (PPAR-γ-antagonist) (10 mg·kg·d of telmisartan and 1 mg·kg·d of GW9662, n = 6), and (4) amlodipine (10 mg·kg·d, n = 8) groups. Telmisartan reduced mean blood pressure compared with that in the control group. There was no statistical difference among the telmisartan, telmisartan + GW9662 and amlodipine groups. The end-diastolic left ventricular diameter was smaller in telmisartan group compared with that in the control group; GW9662 negated the effect of telmisartan. The thickness of the ventricular septum was kept in the telmisartan group compared with that in the control group; GW9662 negated the effect. Histopathologic analyses showed that telmisartan suppressed myocardial fibrosis compared with that of the control, whereas GW9662 negated the telmisartan effect. CONCLUSIONS: Telmisartan suppresses pathological remodeling by PPAR-γ agonistic activities independent of its antihypertensive effects.

Novel effects of macrolide antibiotics on cardiovascular diseases.

Macrolide antibiotics are broadly used for the treatment of various microbial infections. However, they are also known to have multiple biologic effects, such as alteration of inflammatory factors and matrix metalloproteinases (MMPs). Because of controversial results in clinical trials, the effects of macrolides on cardiovascular diseases are still to be elucidated. It has been reported that MMP activity is upregulated in various cardiovascular diseases, such as myocarditis, cardiac transplant rejection and myocardial infarction. However, little is known about the effects of macrolides on cardiovascular diseases. We have reported that clarithromycin suppressed the development of myocarditis, cardiac rejection and myocardial ischemia using animal models. In this article, we reviewed the roles of MMPs in cardiovascular diseases and the effects of macrolides on the prevention of adverse tissue remodeling.

Roles of prostaglandin E2 in cardiovascular diseases.

Prostaglandin E2 (PGE(2)) is produced in inflammatory responses and regulates a variety of immunological reactions through 4 different receptor subtypes; EP1, 2, 3 and 4. However, the precise role of each receptor in cardiovascular disease has not yet been elucidated. Enhanced expression of some EPs has been observed in clinical and experimental cardiovascular diseases. EP agonists have been developed to clarify the role of each receptor. Recently, we developed a novel selective agonist to examine the effects of EP4 on cardiac transplantation, myocardial ischemia, and myocarditis. Of note, a selective EP4 agonist attenuated inflammatory cytokines and chemokines via attenuation of macrophage activation in inflammatory heart diseases. In this review article, we discuss the effects of PGE(2) receptor agonists on the development of cardiovascular diseases.

The anti-inflammatory mechanism of prostaglandin e2 receptor 4 activation in rat experimental autoimmune myocarditis.

Prostaglandins (PG) and their specific receptors for E type PG (EP) play an important role in inflammatory diseases. Although myocarditis results in inflammation of the heart, roles of PG and EP in its pathophysiology is still controversial. To clarify the role of PG and EP on the progression of myocarditis, we used an experimental autoimmune myocarditis model. A selective EP4 (EP4RAG) agonist was administered into both early (Day 0 to 21) and late (Day 14 to 21) -treated groups and the animals were killed on Day 21. We found that improved cardiac function was detected in the EP4RAG-treated groups in comparison to the untreated group. The infiltration area ratio in the early-treated (16.6% ± 4.6%) group was lower than those in the untreated group (32.1% ± 3.5%) (P < 0.05). The fibrosis area ratios in the early-treated (19.2% ± 6.3%) and the late-treated groups (24.4% ± 5.1%) were lower than those in the untreated group (37.4% ± 2.6%), respectively (P < 0.05). Moreover, we found that EP4RAG decreased T-cell proliferation and monocyte chemoattractant protein-1 production in vitro. We concluded that a selective EP4 agonist inactivates T-cells, which turns out to moderate the progression of experimental autoimmune myocarditis. Therefore, EP4 can be an effective target for myocarditis treatment.

Clarithromycin attenuates myocardial ischemia-reperfusion injury.

BACKGROUND: MMP activity is upregulated in the heart after myocardial ischemia reperfusion, and its activation contributes to the changes in left ventricular (LV) dysfunction. A major macrolide antibiotic, clarithromycin has many biological functions including MMP regulation. However, little is known about the effect of clarithromycin in myocardial reperfusion injury via MMPs. Our objective was to clarify the role of MMPs regulated by clarithromycin in the progression of myocardial reperfusion injury. METHODS: We administered clarithromycin to rats with ischemia-reperfusion injury twice a day for 7 days before and 14 days after reperfusion. RESULTS: Clarithromycin resulted in a significant reduction of the infarction area:area at risk ratio and preserved fractional shortening ratio after 14 days of reperfusion. Immunohistochemical analysis revealed that macrophages were the primary cellular source of MMPs. Fewer macrophages were detected in the ischemic area of the hearts following ischemia reperfusion in the clarithromycin-treated group compared with the vehicle-treated group. Although ischemia-reperfusion injury resulted in LV fibrosis with increasing MMP activities, clarithromycin significantly reduced these changes. CONCLUSION: Clarithromycin is effective for attenuating myocardial ischemia-reperfusion injury by suppressing MMPs.

A critical role of sympathetic nerve regulation for the treatment of impaired daily rhythm in hypertensive Dahl rats.

There is a deep relationship between impaired circadian rhythm and hypertension. However, the detailed mechanisms between the daily sleep-wake rhythm and cardiovascular disorders have not yet been elucidated. To clarify the mechanism, we examined salt-sensitive Dahl rats that were fed normal chow (n=10), high-salt chow (n=10) and high-salt chow with bisoprolol (n=10). Simultaneous electroencephalogram, electromyogram and locomotor activity were examined to analyze the sleep-wake state. We also examined heart rate, blood pressure and echocardiographic findings to verify the presence of hypertension. Hypertension with impaired ventricular contraction was observed in the rats with high-salt-chow consumption whereas normal-chow rats did not show these disorders. Although rats with the normal diet showed a standard daily rhythm with normal rapid eye movement (REM) sleep duration and locomotor activity, the high-salt-diet group exhibited an impaired daily rhythm with suppressed REM sleep and significant abnormal locomotor activity. Bisoprolol significantly improved the daily sleep-wake rhythm and locomotor activity. We showed that an impaired daily rhythm was closely related to the development of hypertension. Regulation of sympathetic nerve alterations may have a key role in the treatment of hypertension and circadian rhythm disorder.

Structure-activity relationship of novel DAPK inhibitors identified by structure-based virtual screening.

Death-associated protein kinase (DAPK) is a serine/threonine protein kinase implicated in diverse programmed cell death pathways. DAPK is a promising target protein for the treatment of ischemic diseases. We identified novel potent and selective DAPK inhibitors efficiently by structure-based virtual screening, then further developed the hit compounds. In this paper, we describe the development of the hit compounds and the structure-activity relationship studies of the DAPK inhibitors in detail, including calculation of the solvated interaction energy (SIE), and verification of selectivity using a kinase panel.

Early treatment with clarithromycin attenuates rat autoimmune myocarditis via inhibition of matrix metalloproteinase activity.

BACKGROUND: Matrix metalloproteinase (MMP) activity is upregulated in the hearts with myocarditis, and its activation contributes to the changes in left ventricular function. A major macrolide antibiotic, clarithromycin (CAM), has many biological functions including MMP regulation. However, little is known about the effect of CAM in myocarditis via MMPs. OBJECTIVE: To clarify the role of MMPs regulated by CAM in the progression of myocarditis. Design CAM was given to experimental rats with autoimmune myocarditis (EAM) from day -7 to day 21 (early treated group, n=6) or from day 1 to day 21 (late treated group, n=6) twice a day. RESULTS: Although the non-treated rats showed blood pressure decline and impaired cardiac function, early CAM treatment prevented this progression. Pathologically, severe myocardial cell infiltration (30.5+/-4.2%) and fibrosis (32.2+/-1.1%) were detected in the non-treated group, while early CAM treatment significantly suppressed these changes (infiltration 6.5+/-0.2%, fibrosis 5.9+/-3.9%). Zymography showed that non-treated EAM resulted in enhanced ventricular activities of MMP-9, while early CAM treatment reduced the alteration. However, late CAM treatment was less effective than the early treatment. CONCLUSIONS: Early CAM treatment is effective to attenuate myocarditis by suppressing MMP-9.

Ultrasound-microbubble-mediated intercellular adhesion molecule-1 small interfering ribonucleic acid transfection attenuates neointimal formation after arterial injury in mice.

OBJECTIVES: The purpose of this study was to investigate the efficiency of small interfering ribonucleic acid (siRNA) in murine arteries. We transfected it using a nonviral ultrasound-microbubble-mediated in vivo gene delivery system. BACKGROUND: siRNA is an effective methodology to suppress gene function. The siRNA can be synthesized easily; however, a major obstacle in the use of siRNA as therapeutics is the difficulty involved in effective in vivo delivery. METHODS: To investigate the efficiency of nonviral ultrasound-microbubble-mediated in vivo siRNA delivery, we used a fluorescein-labeled siRNA, green fluorescent protein (GFP) siRNA, and intercellular adhesion molecule (ICAM)-1 siRNA in murine arteries. Murine femoral arteries were injured using flexible wires to establish arterial injury. RESULTS: The fluorescein-labeled siRNA and GFP siRNA showed that this nonviral approach could deliver siRNA into target arteries effectively without any tissue damage and systemic adverse effects. ICAM-1 siRNA transfection into murine injured arteries significantly suppressed the development of neointimal formation in comparison to those in the control group. Immunohistochemistry revealed that accumulation of T cells and adhesion molecule positive cells was observed in nontreated injured arteries, whereas siRNA suppressed accumulation. CONCLUSIONS: The nonviral ultrasound-microbubble delivery of siRNA ensures effective transfection into target arteries. ICAM-1 siRNA has the potential to suppress arterial neointimal formation. Transfection of siRNA can be beneficial for the clinical treatment of cardiovascular and other inflammatory diseases.

Identification of death-associated protein kinases inhibitors using structure-based virtual screening.

Death-associated protein kinases (DAPKs) function in the early stages of eukaryotic programmed cell death. DAPKs are now emerging as targets for drug discovery in novel therapeutic approaches for ischemic diseases in the brain, heart, kidney, and other organs. Using a structure-based virtual screening approach, we discovered potent and selective DAPKs inhibitors. 6 was found to be the most potent inhibitor with enzyme selectivity (IC(50) = 69 nM for DAPK1).

The mechanism of anti-inflammatory effects of prostaglandin E2 receptor 4 activation in murine cardiac transplantation.

BACKGROUND: Prostaglandin E2 (PGE2) is a pathogenesis of inflammatory diseases; PGE2 plays a key role in association of anti-inflammation and immune suppression. EP4, which is a PGE2 receptor, is known to suppress the production of inflammatory cytokines and chemokines in vitro. Although it has been reported that EP4 agonists prolonged cardiac allograft survival, little has been elucidated the immunologic mechanism. METHODS: We injected a selective EP4 agonist (EP4RAG) into recipient mice with heterotopic cardiac transplantation. RESULTS: EP4RAG significantly prolonged the graft survival compared with the vehicle-treated group. Although the vehicle-treated group showed severe myocardial cell infiltration, the EP4RAG-treated group attenuated the development on day 7. EP4RAG suppressed various proinflammatory factors such as cytokines, chemokines, adhesion molecules, and nuclear factor-kappaB (NF-kappaB) compared with the vehicle-treated group. We also demonstrated that EP4RAG suppressed the activation of macrophages, but it did not affect to T lymphocytes in vitro. EP4RAG inhibited the activation of NF-kappaB compared with the control group. CONCLUSION: Pharmacological selective EP4 activation suppressed the production of proinflammatory factors by inhibition of NF-kappaB activity in cardiac transplantation.

Clarithromycin prevents smoke-induced emphysema in mice.

RATIONALE: Modulating the low-grade chronic inflammation in chronic obstructive pulmonary disease remains challenging. Clarithromycin (CAM), a macrolide antibiotic, reportedly ameliorates chronic inflammation via mechanisms independent of its antibacterial activity. OBJECTIVES: The aim of this study was to examine whether CAM can prevent or reduce emphysema induced by chronic cigarette smoke exposure. METHODS: Mice were exposed to cigarette smoke daily for 6 months and treated with orally administered CAM at doses of 25 to 100 mg/kg twice a day throughout the course of the experiment to test the preventive effects. The administration of CAM at 50 or 100 mg/kg was performed during the second half of a 6-month exposure period to assess the therapeutic effects. Histologic analysis was performed to evaluate the effect of CAM. MEASUREMENTS AND MAIN RESULTS: CAM treatment for 6 months decreased airspace enlargement and the destruction of the alveolar walls and impaired the accumulation of macrophages in bronchoalveolar lavage fluid in a dose-related fashion. The administration of clarithromycin at 100 mg/kg in the therapeutic protocol reduced emphysema compared with the smoke-exposed group without treatment. An immunohistologic analysis revealed that CAM reduced the number of F4/80-positive macrophages in the lung parenchyma. In an in vitro test, CAM at 5 to 20 microM directly suppressed the activation of macrophages stimulated with tumor necrosis factor-alpha. CONCLUSIONS: Our data demonstrated that CAM at a clinically achievable dose prevented cigarette smoke-induced emphysema by modulating lung inflammation. This study supports the possibility that low-dose CAM treatment might provide a new therapeutic strategy for chronic obstructive pulmonary diseases.

Pharmacological activation of the prostaglandin E2 receptor EP4 improves cardiac function after myocardial ischaemia/reperfusion injury.

AIMS: Increased expression of several subtypes of prostaglandin E(2) receptors (EP1-4) has recently been described in clinical and experimental myocardial ischaemia/reperfusion (I/R) injury. However, their pathophysiological significance in I/R remains obscure. Thus, we determined whether the activation of the prostanoid receptor, EP4, suppresses myocardial I/R injury. METHODS AND RESULTS: To analyse the role of EP4, we administered an EP4 selective agonist (EP4RAG, 1 or 3 mg/kg) or vehicle to rats with myocardial I/R injury. After 7 days of reperfusion, I/R rats exhibited left ventricular (LV) dilatation and contractile dysfunction with myocyte hypertrophy and interstitial fibrosis. EP4RAG significantly reduced infarction area/ischaemic myocardium (72.4 +/- 0.7 vs. 23.3 +/- 0.6%; P < 0.05) and improved LV contraction and dilatation compared with that of the vehicle. EP4RAG also attenuated the recruitment of inflammatory cells, especially macrophages, and interstitial fibrosis in hearts. Monocyte chemoattractant protein (MCP)-1 and other cytokines were increased in both non-ischaemic (area not at risk, ANAR) and ischaemic (area at risk, AAR) myocardium; however, western blot analysis and RNase protection assay showed that EP4RAG suppressed these changes. Gelatin zymography revealed EP4RAG significantly reduced matrix metalloproteinase-2 and -9 activities in both ANAR and AAR. Chemoattractant assay demonstrated that EP4RAG suppressed the migration of cytokine-stimulated macrophages and decreased the level of MCP-1 production in the supernatant (587.3 +/- 55.3 vs. 171.5 +/- 47.5 pg/mL; P < 0.05). CONCLUSION: The data suggest that the EP4 agonist is effective for attenuation of I/R injury by suppressing MCP-1 and the infiltration of inflammatory cells, especially macrophages.

A novel IKK inhibitor suppresses heart failure and chronic remodeling after myocardial ischemia via MMP alteration.

OBJECTIVE: Amplification of inflammatory response in the non-infarct area plays an important role in the pathogenesis of ventricular remodeling after myocardial ischemia. Activation of nuclear factor-kappa B (NF-kappaB) is involved in this amplification through a positive feedback loop of pro- inflammatory cytokines. We investigated the efficacy of IKK blockade with IMD-0560, a novel inhibitor of IKK, in a rat myocardial ischemia model. METHODS/RESULTS: Left coronary artery occlusion (28 days) was carried out in Sprague-Dawley rats. Daily intraperitoneal injections of IMD-0560 (5 mg/kg) were done after the operation. Treatment with IMD-0560 significantly improved cardiac function as indicated by the preservation of fractional shortening and lower serum brain natriuretic peptide level. Histological analysis showed that IMD-0560 treatment suppressed thinning in the infarcted area compared with vehicle-treated hearts. Moreover, in situ zymography showed matrix metalloprotease-9 activity was inhibited in the infarct area. CONCLUSION: We revealed that the IKK blockade is potent for the suppression of chronic ventricular remodeling after myocardial ischemia.

Clarithromycin attenuates acute and chronic rejection via matrix metalloproteinase suppression in murine cardiac transplantation.

OBJECTIVES: Clarithromycin (CAM), a major macrolide antibiotic, has many biological functions, including matrix metalloproteinases (MMPs) regulation. However, little is known about the effect of CAM in heart transplantation via MMP-9. The purpose of this study was to clarify the role of MMPs regulated by CAM in the progression of rejection. BACKGROUND: The MMPs are critical in the development of inflammation and tissue remodeling. The MMP-9 level is associated with the rejection of heart transplantation. METHODS: We orally administered CAM into murine cardiac allograft recipients. Total allomismatch combination and class II mismatch combination were used for the analysis of graft survival, pathology and molecular. RESULTS: Clarithromycin improved acute rejection judged by graft survival and by myocardial cell infiltrating area in a total allomismatch combination. The CAM-treated allografts showed affected expression of T-cells, macrophages, and MMP-9 in immunohistochemistry. Zymography indicated that enhanced MMPs activities were observed in nontreated hearts, whereas CAM suppressed the levels. In chronic rejection, CAM suppressed the development of graft arterial disease and myocardial remodeling compared with that of nontreatment. Clarithromycin inhibited the expression of MMP-9, whereas the treatment did not alter the expression of MMP-2 and tissue inhibitor metalloproteinase-1 in macrophages and smooth muscle cells. Inhibition of MMP-9 by CAM was associated with suppression of smooth muscle cell migration and proliferation. CONCLUSIONS: Clarithromycin is useful to suppress allograft remodeling, because it is critically involved in the prevention of cardiac rejection through the suppression of MMP-9.