MMPs 2 and 9 are essential for coronary collateral growth and are prominently regulated by p38 MAPK

Interleukin-38 suppresses abdominal aortic aneurysm formation in mice by regulating macrophages in an IL1RL2-p38 pathway-dependent manner

Macrophages play crucial roles in abdominal aortic aneurysm (AAA) formation through the inflammatory response and extracellular matrix degradation; therefore, regulating macrophages may suppress AAA formation. Interleukin-38 (IL-38) is a member of the IL-1 family, which binds to IL-36 receptor (IL1RL2) and has an anti-inflammation effect. Because macrophages express IL1RL2, we hypothesized that IL-38 suppresses AAA formation by controlling macrophages. We assessed a C57BL6/J mouse angiotensin II-induced AAA model with or without IL-38 treatment. RAW 264.7 cells were cultured with tumor necrosis factor-α and treated with or without IL-38. Because p38 has important roles in inflammation, we assessed p38 phosphorylation in vitro and in vivo. To clarify whether the IL-38 effect depends on the p38 pathway, we used SB203580 to inhibit p38 phosphorylation. IL1RL2+ macrophage accumulation along with matrix metalloproteinase (MMP)-2 and -9 expression was observed in mouse AAA. IL-38 reduced the incidence of AAA formation along with reduced M1 macrophage accumulation and MMP-2 and -9 expression in the AAA wall. Macrophage activities including inducible nitric oxide, MMP-2, and MMP-9 production and spindle-shaped changes were significantly suppressed by IL-38. Furthermore, we revealed that inhibition of p38 phosphorylation diminished the effects of IL-38 on regulating macrophages to reduce AAA incidence, indicating the protective effects of IL-38 depend on the p38 pathway. IL-38 plays protective roles against AAA formation through regulation of macrophage accumulation in the aortic wall and modulating the inflammatory phenotype. Using IL-38 may be a novel therapy for AAA patients.

p38 MAPK priming boosts VSMC proliferation and arteriogenesis by promoting PGC1α-dependent mitochondrial dynamics

Vascular smooth muscle cell (VSMC) proliferation is essential for arteriogenesis to restore blood flow after artery occlusion, but the mechanisms underlying this response remain unclear. Based on our previous findings showing increased VSMC proliferation in the neonatal aorta of mice lacking the protease MT4-MMP, we aimed at discovering new players in this process. We demonstrate that MT4-MMP absence boosted VSMC proliferation in vitro in response to PDGF-BB in a cell-autonomous manner through enhanced p38 MAPK activity. Increased phospho-p38 in basal MT4-MMP-null VSMCs augmented the rate of mitochondrial degradation by promoting mitochondrial morphological changes through the co-activator PGC1α as demonstrated in PGC1α^−/− VSMCs. We tested the in vivo implications of this pathway in a novel conditional mouse line for selective MT4-MMP deletion in VSMCs and in mice pre-treated with the p38 MAPK activator anisomycin. Priming of p38 MAPK activity in vivo by the absence of the protease MT4-MMP or by anisomycin treatment led to enhanced arteriogenesis and improved flow recovery after femoral artery occlusion. These findings may open new therapeutic opportunities for peripheral vascular diseases.

Simultaneous Upregulation of Elastolytic and Elastogenic Factors Are Necessary for Regulated Collateral Diameter Expansion

Background: During arteriogenesis, outward remodeling of the arterial wall expands luminal diameter to produce increased conductance in developing collaterals. We have previously shown that diameter expansion without loss of internal elastic lamina (IEL) integrity requires both degradation of elastic fibers and LOX-mediated repair. The aim of this study was to investigate the expression of genes involved in remodeling of the extracellular matrix (ECM) using a model of arteriogenesis. Methods: Sprague-Dawley rats underwent femoral artery ligation with distal arteriovenous fistula (FAL + AVF) placement. Profunda femoral arteries (PFA) were harvested for analysis at various time points. Serum desmosine, an amino acid found exclusively in elastin, was evaluated with enzyme-linked immunosorbent assay (ELISA) as a marker of tissue elastolysis. Tissue mRNA isolated from FAL + AVF exposed PFAs was compared to the contralateral sham-operated using qPCR. HCAECs were cultured under low shear stress (8 dyn·s/cm 2) for 24 h and then exposed to high shear stress (40 dyn·s/cm 2) for 2-6 h. Primers used included FBN-1, FBN-2, Timp-2, LOX-1, Trop-E, Cath-K, Cath-S, MMP-2, MMP-9, FBLN-4, and FBLN-5 and were normalized to GAPDH. mRNA fold changes were quantified using the 2-ΔΔCq method. Comparisons between time points were made with non-parametric ANOVA analysis with Bonferroni adjustment. Results: PFAs showed IEL reorganization during arteriogenesis. Serum desmosine levels are significantly elevated at 2 days and one week, with a return to baseline thereafter (p < 0.01). Expression of ECM structural proteins (FBN-1, FBN-2, FBLN-4, FBLN-5, Tropoelastin, TIMP-2, LOX-1) and elastolytic proteins (MMP-2, MMP-9, Cathepsin S, Cathepsin K) exhibited an early peak (p < 0.05) relative to sham PFAs. After two weeks, expression returned to baseline. HCAECs demonstrated upregulation of FBN-2, FBLN-5, LOX-1 and Trop-E at 4 h of high shear stress, as well as elastolytic protein MMP-2. Conclusions: Elastin degradation begins early in arteriogenesis and is mediated by local upregulation of elastolytic genes. Elastolysis appears to be simultaneously balanced by production of elastic fiber components which may facilitate stabilization of the IEL. Endothelial cells are central to initiation of arteriogenesis and begin ECM remodeling in response to altered shear stress.

Elastic Laminar Reorganization Occurs with Outward Diameter Expansion during Collateral Artery Growth and Requires Lysyl Oxidase for Stabilization

When a large artery becomes occluded, hemodynamic changes stimulate remodeling of arterial networks to form collateral arteries in a process termed arteriogenesis. However, the structural changes necessary for collateral remodeling have not been defined. We hypothesize that deconstruction of the extracellular matrix is essential to remodel smaller arteries into effective collaterals. Using multiphoton microscopy, we analyzed collagen and elastin structure in maturing collateral arteries isolated from ischemic rat hindlimbs. Collateral arteries harvested at different timepoints showed progressive diameter expansion associated with striking rearrangement of internal elastic lamina (IEL) into a loose fibrous mesh, a pattern persisting at 8 weeks. Despite a 2.5-fold increase in luminal diameter, total elastin content remained unchanged in collaterals compared with control arteries. Among the collateral midzones, baseline elastic fiber content was low. Outward remodeling of these vessels with a 10-20 fold diameter increase was associated with fractures of the elastic fibers and evidence of increased wall tension, as demonstrated by the straightening of the adventitial collagen. Inhibition of lysyl oxidase (LOX) function with β-aminopropionitrile resulted in severe fragmentation or complete loss of continuity of the IEL in developing collaterals. Collateral artery development is associated with permanent redistribution of existing elastic fibers to accommodate diameter growth. We found no evidence of new elastic fiber formation. Stabilization of the arterial wall during outward remodeling is necessary and dependent on LOX activity.

Structural Remodeling of the Extracellular Matrix in Arteriogenesis: A Review

Lower extremity arterial occlusive disease (AOD) results in significant morbidity and mortality for the population, with up to 10% of patients ultimately requiring amputation. An alternative method for non-surgical revascularization which is yet to be fully understood is the optimization of the body's own natural collateral arterial network in a process known as arteriogenesis. Under conditions of conductance vessel stenosis or occlusion resulting in increased flow, shear forces, and pressure gradients within collaterals, positive remodeling occurs to increase the diameter and capacity of these vessels. The creation of a distal arteriovenous fistula (AVF) will drive increased arteriogenesis as compared to collateral formation with the occlusion of a conductance vessel alone by further increasing flow through these arterioles, demonstrating the capacity for arteriogenesis to form larger, more efficient collaterals beyond what is spontaneously achieved after arterial occlusion. Arteries rely on an extracellular matrix (ECM) composed of elastic fibers and collagens that provide stability under hemodynamic stress, and ECM remodeling is necessary to allow for increased diameter and flow conductance in mature arterial structures. When positive remodeling occurs, digestion of lamella and the internal elastic lamina (IEL) by matrix metalloproteinases (MMPs) and other elastases results in the rearrangement and thinning of elastic structures and may be replaced with disordered elastin synthesis without recovery of elastic function. This results in transmission of wall strain to collagen and potential for aneurysmal degeneration along collateral networks, as is seen in the pancreaticoduodenal artery (PDA) after celiac occlusion and inferior mesenteric artery (IMA) with concurrent celiac and superior mesenteric artery (SMA) occlusions. Further understanding into the development of collaterals is required to both better understand aneurysmal degeneration and optimize collateral formation in AOD.

Vessel Enlargement in Development and Pathophysiology

From developmental stages until adulthood, the circulatory system remodels in response to changes in blood flow in order to maintain vascular homeostasis. Remodeling processes can be driven by de novo formation of vessels or angiogenesis, and by the restructuration of already existing vessels, such as vessel enlargement and regression. Notably, vessel enlargement can occur as fast as in few hours in response to changes in flow and pressure. The high plasticity and responsiveness of blood vessels rely on endothelial cells. Changes within the bloodstream, such as increasing shear stress in a narrowing vessel or lowering blood flow in redundant vessels, are sensed by endothelial cells and activate downstream signaling cascades, promoting behavioral changes in the involved cells. This way, endothelial cells can reorganize themselves to restore normal circulation levels within the vessel. However, the dysregulation of such processes can entail severe pathological circumstances with disturbances affecting diverse organs, such as human hereditary telangiectasias. There are different pathways through which endothelial cells react to promote vessel enlargement and mechanisms may differ depending on whether remodeling occurs in the adult or in developmental models. Understanding the molecular mechanisms involved in the fast-adapting processes governing vessel enlargement can open the door to a new set of therapeutical approaches to be applied in occlusive vascular diseases. Therefore, we have outlined here the latest advances in the study of vessel enlargement in physiology and pathology, with a special insight in the pathways involved in its regulation.

The many flavors of monocyte/macrophage--endothelial cell interactions

PURPOSE OF REVIEW

The well recognized plasticity and diversity, typical of monocytes and macrophages have recently been expanded by the knowledge that additional macrophage lineages originated directly from embryonic progenitors, populate and establish residency in all tissues examined so far. This review aims to summarize our current understanding on the diversity of monocyte/macrophage subtypes associated with the vasculature, their specific origins, and nature of their cross-talk with the endothelium.

RECENT FINDINGS

Taking stock of the many interactions between the endothelium and monocytes/macrophages reveals a far more intricate and ever-growing depth. In addition to circulating and surveilling the endothelium, monocytes can specifically be differentiated into patrolling cells that crawl on the surface of the endothelium and promote homeostasis. The conversion of classical to patrolling is endothelium-dependent uncovering an important functional link. In addition to patrolling cells, the endothelium also recruits and harbor an intimal-resident myeloid population that resides in the tunica intima in the absence of pathological insults. Moreover, the adventitia is populated with resident macrophages that support blood vessel integrity and prevent fibrosis.

SUMMARY

The last few years have witnessed a significant expansion in our knowledge of the many subtypes of monocytes and macrophages and their corresponding functional interactions with the vascular wall. In addition to surveying the endothelium for opportunities of diapedeses, monocyte and macrophages take residence in both the intima (as patrolling or resident) and in the adventitia. Their contributions to vascular function are broad and critical to homeostasis, regeneration, and expansion.

Reperfused hemorrhagic myocardial infarction in rats

BACKGROUND

Intramyocardial hemorrhage following reperfusion is strongly associated with major adverse cardiovascular events in myocardial infarction (MI) patients; yet the mechanisms contributing to these outcomes are not well understood. Large animal models have been used to investigate intramyocardial hemorrhage, but they are exorbitantly expensive and difficult to use for mechanistic studies. In contrast, rat models are widely used to investigate mechanistic aspects of cardiovascular physiology, but a rat model that consistently recapitulates the characteristics of an hemorrhagic MI does not exist. To bridge this gap, we investigated the physiological conditions of MI that would create intramyocardial hemorrhage in rats so that a reliable model of hemorrhagic MI would become available for basic research.

METHODS & RESULTS

Sprague-Dawley rats underwent either a 90-minute (90-min) ischemia and then reperfusion (I/R) (n = 22) or 30-minute (30-min) I/R (n = 18) of the left anterior descending coronary artery. Sham rats (n = 12) were used as controls. 90-min I/R consistently yielded hemorrhagic MI, while 30-min I/R consistently yielded non-hemorrhagic MI. Twenty-four hours post-reperfusion, ex-vivo late-gadolinium-enhancement (LGE) and T2* cardiac MRI performed on excised hearts from 90-min I/R rats revealed colocalization of iron deposits within the scarred tissue; however, in 30-min I/R rats scar was evident on LGE but no evidence of iron was found on T2* CMR. Histological studies verified tissue damage (H&E) detected on LGE and the presence of iron (Perl's stain) observed on T2*-CMR. At week 4 post-reperfusion, gene and protein expression of proinflammatory markers (TNF-α, IL-1β and MMP-9) were increased in the 90-min I/R group when compared to 30-min I/R groups. Further, transmission electron microscopy performed on 90-min I/R myocardium that were positive for iron on T2* CMR and Perl's stain showed accumulation of granular iron particles within the phagosomes.

CONCLUSION

Ischemic time prior to reperfusion is a critical factor in determining whether a MI is hemorrhagic or non-hemorrhagic in rats. Specifically, a period of 90-min of ischemia prior to reperfusion can produce rat models of hemorrhagic MI, while 30-minutes of ischemia prior to reperfusion can ensure that the MIs are non-hemorrhagic. Hemorrhagic MIs in rats result in marked increase in iron deposition, proinflammatory burden and adverse left-ventricular remodeling compared to rats with non-hemorrhagic MIs.

Recruitment and maturation of the coronary collateral circulation: Current understanding and perspectives in arteriogenesis

The coronary collateral circulation is a rich anastomotic network of primitive vessels which have the ability to augment in size and function through the process of arteriogenesis. In this review, we evaluate the current understandings of the molecular and cellular mechanisms by which this process occurs, specifically focussing on elevated fluid shear stress (FSS), inflammation, the redox state and gene expression along with the integrative, parallel and simultaneous process by which this occurs. The initiating step of arteriogenesis occurs following occlusion of an epicardial coronary artery, with an increase in FSS detected by mechanoreceptors within the endothelium. This must occur within a 'redox window' where an equilibrium of oxidative and reductive factors are present. These factors initially result in an inflammatory milieu, mediated by neutrophils as well as lymphocytes, with resultant activation of a number of downstream molecular pathways resulting in increased expression of proteins involved in monocyte attraction and adherence; namely vascular cell adhesion molecule 1 (VCAM-1), monocyte chemoattractant protein 1 (MCP-1) and transforming growth factor beta (TGF-β). Once monocytes and other inflammatory cells adhere to the endothelium they enter the extracellular matrix and differentiate into macrophages in an effort to create a favourable environment for vessel growth and development. Activated macrophages secrete inflammatory cytokines such as tumour necrosis factor-α (TNF-α), growth factors such as fibroblast growth factor-2 (FGF-2) and matrix metalloproteinases. Finally, vascular smooth muscle cells proliferate and switch to a contractile phenotype, resulting in an increased diameter and functionality of the collateral vessel, thereby allowing improved perfusion of the distal myocardium subtended by the occluded vessel. This simultaneously reduces FSS within the collateral vessel, inhibiting further vessel growth.

Loss of Protease-Activated Receptor 4 Prevents Inflammation Resolution and Predisposes the Heart to Cardiac Rupture After Myocardial Infarction

BACKGROUND

Cardiac rupture is a major lethal complication of acute myocardial infarction (MI). Despite significant advances in reperfusion strategies, mortality from cardiac rupture remains high. Studies suggest that cardiac rupture can be accelerated by thrombolytic therapy, but the relevance of this risk factor remains controversial.

METHODS

We analyzed protease-activated receptor 4 (Par4) expression in mouse hearts with MI and investigated the effects of Par4 deletion on cardiac remodeling and function after MI by echocardiography, quantitative immunohistochemistry, and flow cytometry.

RESULTS

Par4 mRNA and protein levels were increased in mouse hearts after MI and in isolated cardiomyocytes in response to hypertrophic and inflammatory stimuli. Par4-deficient mice showed less myocyte apoptosis, reduced infarct size, and improved functional recovery after acute MI relative to wild-type (WT). Conversely, Par4^-/- mice showed impaired cardiac function, greater rates of myocardial rupture, and increased mortality after chronic MI relative to WT. Pathological evaluation of hearts from Par4^-/- mice demonstrated a greater infarct expansion, increased cardiac hemorrhage, and delayed neutrophil accumulation, which resulted in impaired post-MI healing compared with WT. Par4 deficiency also attenuated neutrophil apoptosis in vitro and after MI in vivo and impaired inflammation resolution in infarcted myocardium. Transfer of Par4^-/- neutrophils, but not of Par4^-/- platelets, in WT recipient mice delayed inflammation resolution, increased cardiac hemorrhage, and enhanced cardiac dysfunction. In parallel, adoptive transfer of WT neutrophils into Par4^-/- mice restored inflammation resolution, reduced cardiac rupture incidence, and improved cardiac function after MI.

CONCLUSIONS

These findings reveal essential roles of Par4 in neutrophil apoptosis and inflammation resolution during myocardial healing and point to Par4 inhibition as a potential therapy that should be limited to the acute phases of ischemic insult and avoided for long-term treatment after MI.

Arteriogenesis of the Spinal Cord-The Network Challenge

Spinal cord ischemia (SCI) is a clinical complication following aortic repair that significantly impairs the quality and expectancy of life. Despite some strategies, like cerebrospinal fluid drainage, the occurrence of neurological symptoms, such as paraplegia and paraparesis, remains unpredictable. Beside the major blood supply through conduit arteries, a huge collateral network protects the central nervous system from ischemia—the paraspinous and the intraspinal compartment. The intraspinal arcades maintain perfusion pressure following a sudden inflow interruption, whereas the paraspinal system first needs to undergo arteriogenesis to ensure sufficient blood supply after an acute ischemic insult. The so-called steal phenomenon can even worsen the postoperative situation by causing the hypoperfusion of the spine when, shortly after thoracoabdominal aortic aneurysm (TAAA) surgery, muscles connected with the network divert blood and cause additional stress. Vessels are a conglomeration of different cell types involved in adapting to stress, like endothelial cells, smooth muscle cells, and pericytes. This adaption to stress is subdivided in three phases—initiation, growth, and the maturation phase. In fields of endovascular aortic aneurysm repair, pre-operative selective segmental artery occlusion may enable the development of a sufficient collateral network by stimulating collateral vessel growth, which, again, may prevent spinal cord ischemia. Among others, the major signaling pathways include the phosphoinositide 3 kinase (PI3K) pathway/the antiapoptotic kinase (AKT) pathway/the endothelial nitric oxide synthase (eNOS) pathway, the Erk1, the delta-like ligand (DII), the jagged (Jag)/NOTCH pathway, and the midkine regulatory cytokine signaling pathways.

The apatinib inhibits breast cancer cell line MDA-MB-231 in vitro by inducing apoptosis, cell cycle arrest, and regulating nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways

BACKGROUND AND PURPOSE

Breast cancer is one of the most common cancers and leading causes of death in the women worldwide. The evidence shows efficacy of apatinib against breast cancer. Accordingly, the present study was conducted to investigate the effect of apatinib on apoptosis, cell cycle, and Mitogen‑Activated Protein Kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways in the breast cancer MDA-MB-231 cell line.

METHODS

The effects of apatinib on viability, morphology, tumor spheroid, cell cycle, migration, invasion, and apoptosis of MDA-MB-231 breast cancer cells were evaluated in vitro. In addition, expression of proteins involved in NF-κB and MAPK signaling pathways was evaluated using the western blotting analysis.

RESULTS

Apatinib decreased viability, tumor spheroid, migration, and invasion of MDA-MB-231 cells. Furthermore, apatinib altered morphology and regulated cell cycle which followed by apoptosis induction in MDA-MB-231 cells. Apatinib decreased expression of p-p65 and p65 proteins in NF-κB signaling pathways and increased expression of p38, p-p38, JNK, and p-JNK in MAPK signaling pathways.

CONCLUSION

The results suggested that apatinib can inhibit proliferation, migration and invasion of breast cancer cell line MDA-MB-231 through inducing apoptosis, cell cycle arrest, and regulating NF-κB and MAPK signaling pathways.

Transcriptome sequencing reveals fibrotic associated-genes involved in bovine mammary fibroblasts with Staphylococcus aureus

Bovine mammary fibrosis represents a considerable health problem of cows, primarily indicated by lactation failure. Staphylococcus aureus (S. aureus) can cause mammary damage, this multifactorial disease necessitates to identify how and to what extent molecular pathogen defense mechanisms prevent bacterial infections in bovine mammary gland. In this study, we have aimed to determine the transcriptional responses in bovine mammary fibroblasts (BMFBs) induced by S. aureus using bioinformatics analysis to determine whether mRNA expression profile changes between BMFBs activation and quiescence. Established primary BMFBs obtained from healthy Holstein bovine were induced 10⁶ CFU/mL heat-inactivated S. aureus and total RNA was isolated 6 h after treatment. The 574 DEGs were involved in gene ontology (GO) that were immune response, apoptotic process, extracellular region, receptor binding, endopeptidase activity and protein kinase activity et al. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, distinct pathway contained signaling molecules common to various inflammatory and fibrotic pathways were Pathways in cancer, Cytokine-cytokine receptor interaction, PI3K-Akt signaling pathway, TNF signaling pathway, MAPK signaling pathway and Toll-like receptor signaling pathway. The BMFBs was treated with heat-inactivated S. aureus (10⁶ CFU/mL) and also with pharmacological inhibitors of ERK1/2, P38 MAPK and JNK. The MMP-2 activity were examined gelatin zymography, MMP-2, TIMP-1, -2 and PLAU/PAI-1 protein expression were examined in vitro by western blot. The MMP-2 activity was significantly inhibited by simultaneous inhibition of ERK1/2, P38 MAPK and JNK, and MMP-2, TIMP-1,-2 and PLAU/PAI-1 protein expression were significantly decreased by inhibiting ERK1/2, P38 MAPK or JNK. This suggested a crosstalk between the ERK1/2, P38 MAPK or JNK signaling pathways in regulating extracellular matrix metabolism in the BMFBs with S. aureus. Our study complement our initial study on S. aureus-induced responses by fibrosis-associated genes in BMFBs. This may lead to development of novel therapeutic targets to control bovine mammary fibrosis induced by S. aureus.

Timosaponin AIII: A novel potential anti-tumor compound from Anemarrhena asphodeloides

Timosaponin AIII, a major steroidal saponin found in Anemarrhena asphodeloides Bge., which has been widely used as anti-pyretic, anti-diabetic, anti-inflammatory, anti-platelet aggregator and anti-depressant agents in traditional Chinese medicine. Recent pharmacological study showed that timosaponin AIII had potent cytotoxicity, which was potential to be developed as an anticancer agent, however the molecular mechanism underlying the anticancer activity has not been fully elucidated. This review aims to give a systematic summary of the study of timosaponin AIII to reveal its anti-tumor activities by investigating invasion and migration, apoptosis, autophagy and reversing multi-drug resistance. Furthermore, we also make an overview of the mechanisms identified till now. These meaningful findings may provide novel insights on exploiting timosaponin AIII as a new anti-tumor agent.

Nobiletin inhibits breast cancer via p38 mitogen-activated protein kinase, nuclear transcription factor-κB, and nuclear factor erythroid 2-related factor 2 pathways in MCF-7 cells

INTRODUCTION

Breast cancer is one of the most commonly diagnosed cancers in women, with a high mortality rate.

OBJECTIVE

In the present study, we evaluated the anticancer effect of nobiletin, a flavone glycoside, on the breast cancer cell line MCF-7.

RESULT

Cell viability and proliferation decreased and cell morphology changed from diamond to round after being treated with nobiletin. Nobiletin induced apoptosis of breast cancer MCF-7 cells via regulating the protein expression of Bax, Bcl-2, cleaved caspase-3, and p53. The expression of Bcl-2 decreased, while the expression of Bax and p53 increased in MCF-7 cells treated with nobiletin. Meanwhile, nobiletin inhibited cell migration by downregulating the protein expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). Moreover, phosphorylation of p38 was increased, and the translocation of p65 and nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus was decreased, which suggested that the anticancer effects of nobiletin might at least partially rely on mediating the p38 mitogen-activated protein kinase, nuclear transcription factor-κB, and Nrf2 pathways in MCF-7 breast cancer cells.

CONCLUSION AND RECOMMENDATION

Our data showed that nobiletin was a potential antitumor drug, and it provided some experimental basis for the clinical application of tumor therapy.

Cellular and Molecular Heterogeneity Associated with Vessel Formation Processes

The microvasculature heterogeneity is a complex subject in vascular biology. The difficulty of building a dynamic and interactive view among the microenvironments, the cellular and molecular heterogeneities, and the basic aspects of the vessel formation processes make the available knowledge largely fragmented. The neovascularisation processes, termed vasculogenesis, angiogenesis, arteriogenesis, and lymphangiogenesis, are important to the formation and proper functioning of organs and tissues both in the embryo and the postnatal period. These processes are intrinsically related to microvascular cells, such as endothelial and mural cells. These cells are able to adjust their activities in response to the metabolic and physiological requirements of the tissues, by displaying a broad plasticity that results in a significant cellular and molecular heterogeneity. In this review, we intend to approach the microvasculature heterogeneity in an integrated view considering the diversity of neovascularisation processes and the cellular and molecular heterogeneity that contribute to microcirculatory homeostasis. For that, we will cover their interactions in the different blood-organ barriers and discuss how they cooperate in an integrated regulatory network that is controlled by specific molecular signatures.

MMP-2 and MMP-9 contribute to the angiogenic effect produced by hypoxia/15-HETE in pulmonary endothelial cells

Matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) are the predominant gelatinases in the developing lung. Studies have shown that the expression of MMP-2 and MMP-9 is upregulated in hypoxic fibroblasts, 15-hydroxyeicosatetraenoic acid (15-HETE) regulated fibroblasts migration via modulating MMP-2 or MMP-9, and that hypoxia/15-HETE is a predominant contributor to the development of pulmonary arterial hypertension (PAH) through increased angiogenesis. However, the roles of MMP-2 and MMP-9 in pulmonary arterial endothelial cells (PAECs) angiogenesis as well as the molecular mechanism of hypoxia-regulated MMP-2 and MMP-9 expression have not been identified. The aim of this study was to investigate the role of MMP-2 and MMP-9 in PAEC proliferation and vascular angiogenesis and to determine the effects of hypoxia-induced 15-HETE on the expression of MMP-2 and MMP-9. Western blot, immunofluorescence, and real-time PCR were used to measure the expression of MMP-2 and MMP-9 in hypoxic PAECs. Immunohistochemical staining, flow cytometry, and tube formation as well as cell proliferation, viability, scratch-wound, and Boyden chamber migration assays were used to identify the roles and relationships between MMP-2, MMP-9, and 15-HETE in hypoxic PAECs. We found that hypoxia increased MMP-2 and MMP-9 expression in pulmonary artery endothelium both in vivo and in vitro in a time-dependent pattern. Moreover, administration of the MMP-2 and MMP-9 inhibitor MMI-166 significantly reversed hypoxia-induced increases in right ventricular systemic pressure (RVSP), right ventricular function, and thickening of the tunica media. Furthermore, up-regulation of MMP-2 and MMP-9 expression was induced by 15-HETE, which regulates PAEC proliferation, migration, and cell cycle transition that eventually leads to angiogenesis. Our study demonstrated that hypoxia increases the expression of MMP-2 and MMP-9 through the 15-lipoxygenase/15-HETE pathway, and that MMP-2 and MMP-9 promote PAEC angiogenesis. These findings suggest that MMP-2 and MMP-9 may serve as new potential therapeutic targets for the treatment of PAH.

Elevated 20-HETE in metabolic syndrome regulates arterial stiffness and systolic hypertension via MMP12 activation

Arterial stiffness plays a causal role in development of systolic hypertension. 20-hydroxyeicosatetraeonic acid (20-HETE), a cytochrome P450 (CYP450)-derived arachidonic acid metabolite, is known to be elevated in resistance arteries in hypertensive animal models and loosely associated with obesity in humans. However, the role of 20-HETE in the regulation of large artery remodeling in metabolic syndrome has not been investigated. We hypothesized that elevated 20-HETE in metabolic syndrome increases matrix metalloproteinase 12 (MMP12) activation leading to increased degradation of elastin, increased large artery stiffness and increased systolic blood pressure. 20-HETE production was increased ~7 fold in large, conduit arteries of metabolic syndrome (JCR:LA-cp, JCR) vs. normal Sprague-Dawley (SD) rats. This correlated with increased elastin degradation (~7 fold) and decreased arterial compliance (~75% JCR vs. SD). 20-HETE antagonists blocked elastin degradation in JCR rats concomitant with blocking MMP12 activation. 20-HETE antagonists normalized, and MMP12 inhibition (pharmacological and MMP12-shRNA-Lnv) significantly improved (~50% vs. untreated JCR) large artery compliance in JCR rats. 20-HETE antagonists also decreased systolic (182 ± 3 mmHg JCR, 145 ± 3 mmHg JCR + 20-HETE antagonists) but not diastolic blood pressure in JCR rats. Whereas diastolic pressure was fully angiotensin II (Ang II)-dependent, systolic pressure was only partially Ang II-dependent, and large artery stiffness was Ang II-independent. Thus, 20-HETE-dependent regulation of systolic blood pressure may be a unique feature of metabolic syndrome related to high 20-HETE production in large, conduit arteries, which results in increased large artery stiffness and systolic blood pressure. These findings may have implications for management of systolic hypertension in patients with metabolic syndrome.

Dickkopf‑3 upregulation mediates the cardioprotective effects of curcumin on chronic heart failure

Curcumin, isolated from rhizome of turmeric, has been widely studied as a potential therapeutic drug for cancer. However, protective effects of curcumin on chronic heart failure (CHF) have not been fully studied. In the present study, the effects of curcumin on CHF and the underlying mechanisms were investigated. A total of 40 rabbits were randomized into 4 groups: Control rabbits fed with placebo (Con) or curcumin (Con‑cur), CHF rabbits fed with placebo (CHF) or curcumin (CHF‑cur). CHF was induced by volume and pressure overload. The effects of curcumin on cardiac function and left ventricular (LV) structure were assessed by echocardiography and histology. The effects of curcumin on CHF molecular biomarkers were detected by dihydroethidium and immunohistochemical staining. The effects of curcumin on Dickkopf‑related protein 3 (DKK‑3), p38 mitogen‑activated protein kinase (p38), c‑Jun N‑terminal kinase (JNK) and apoptosis signal‑regulating kinase 1 (ASK1) were assessed by immunohistochemical staining and western blot analysis. Cardiac dysfunction and LV remodeling were successfully produced by ten weeks volume overload and eight weeks pressure overload in the CHF group. Compared with the Con group, the CHF group demonstrated higher levels of CHF molecular biomarkers, a lower level of DKK‑3 expression and alterations of p38, JNK and ASK1 protein expression. Curcumin alleviated all those abnormalities markedly in the CHF‑cur group. In summary, curcumin may exert cardioprotective effects by up‑regulating DKK‑3, which in turn may inhibit p38 and JNK signaling pathways in an ASK1‑dependent way. The present study demonstrated that Dickkopf‑3 upregulation mediates the cardioprotective effects of curcumin on chronic heart failure for the first time.

Rapamycin inhibits CaCl2-induced thoracic aortic aneurysm formation in rats through mTOR-mediated suppression of proinflammatory mediators

The aim of the present study was to investigate the effect of the mammalian target of rapamycin (mTOR) signaling pathway on thoracic aortic aneurysm (TAA) development. The study used a calcium chloride (CaCl₂)-induced rat TAA model to explore the potential role of mTOR signaling pathway in the disease development. Adult male Sprague-Dawley rats underwent the periarterial exposure of thoracic aorta to either 0.5 M CaCl₂ or normal saline, and a subgroup of CaCl₂-treated rats received rapamycin 1 day prior to surgery. Without pre-administering rapamycin, significantly enhanced phosphorylation of mTOR and expression of proinflammatory cytokines [i.e., tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin (IL)-1β] were observed in the CaCl₂-treated aortic segments 2 days post-treatment compared with the NaCl-treated segments. At 2 weeks post-treatment, hematoxylin and eosin and Verhoeff-Van Gieson staining revealed aneurysmal alteration and disappearance of normal wavy elastic structures in the aortic segments exposed to CaCl₂. In contrast, the CaCl₂-induced TAA formation was inhibited by pre-administering rapamycin to CaCl₂-treated rats, which demonstrated attenuated mTOR phosphorylation and downregulation of the proinflammatory mediators (i.e., TNF-α, IL-6, IL-1β, matrix metallopeptidases 2 and 9) to the control level. Further in vitro cell culture experiments using aortic smooth muscle cell (SMC) suggested that the inhibition of the mTOR signaling pathway by rapamycin could promote the differentiation of SMCs, as reflected by the reduced expression of S100A4 and osteopontin. The present study indicated that the early enhanced mTOR signaling pathway in the TAA development and mTOR inhibitor rapamycin may inhibit CaCl₂-induced TAA formation.

Elevated 20-HETE impairs coronary collateral growth in metabolic syndrome via endothelial dysfunction

Coronary collateral growth (CCG) is impaired in metabolic syndrome (MetS). microRNA-145 (miR-145-Adv) delivery to our rat model of MetS (JCR) completely restored and neutrophil depletion significantly improved CCG. We determined whether low endogenous levels of miR-145 in MetS allowed for elevated production of 20-hydroxyeicosatetraenoic acid (20-HETE), which, in turn, resulted in excessive neutrophil accumulation and endothelial dysfunction leading to impaired CCG. Rats underwent 0-9 days of repetitive ischemia (RI). RI-induced cardiac CYP4F (neutrophil-specific 20-HETE synthase) expression and 20-HETE levels were increased (4-fold) in JCR vs. normal rats. miR-145-Adv and 20-HETE antagonists abolished and neutrophil depletion (blocking antibodies) reduced (~60%) RI-induced increases in CYP4F expression and 20-HETE production in JCR rats. Impaired CCG in JCR rats (collateral-dependent blood flow using microspheres) was completely restored by 20-HETE antagonists [collateral-dependent zone (CZ)/normal zone (NZ) flow ratio was 0.76 ± 0.07 in JCR + 20-SOLA, 0.84 ± 0.05 in JCR + 20-HEDGE vs. 0.11 ± 0.02 in JCR vs. 0.84 ± 0.03 in normal rats]. In JCR rats, elevated 20-HETE was associated with excessive expression of endothelial adhesion molecules and neutrophil infiltration, which were reversed by miR-145-Adv. Endothelium-dependent vasodilation of coronary arteries, endothelial nitric oxide synthase (eNOS) Ser1179 phosphorylation, eNOS-dependent NO^·- production and endothelial cell survival were compromised in JCR rats. These parameters of endothelial dysfunction were completely reversed by 20-HETE antagonism or miR-145-Adv delivery, whereas neutrophil depletion resulted in partial reversal (~70%). We conclude that low miR-145 in MetS allows for increased 20-HETE, mainly from neutrophils, which compromises endothelial cell survival and function leading to impaired CCG. 20-HETE antagonists could provide viable therapy for restoration of CCG in MetS.NEW & NOTEWORTHY Elevated 20-hydroxyeicosatetraenoic acid (20-HETE) impairs coronary collateral growth (CCG) in metabolic syndrome by eliciting endothelial dysfunction and apoptosis via excessive neutrophil infiltration. 20-HETE antagonists completely restore coronary collateral growth in metabolic syndrome. microRNA-145 (miR-145) is an upstream regulator of 20-HETE production in metabolic syndrome; low expression of miR-145 in metabolic syndrome promotes elevated production of 20-HETE.

Baicalin Attenuates Hypoxia-Induced Pulmonary Arterial Hypertension to Improve Hypoxic Cor Pulmonale by Reducing the Activity of the p38 MAPK Signaling Pathway and MMP-9

Baicalin has a protective effect on hypoxia-induced pulmonary hypertension in rats, but the mechanism of this effect remains unclear. Thus, investigating the potential mechanism of this effect was the aim of the present study. Model rats that display hypoxic pulmonary hypertension and cor pulmonale under control conditions were successfully generated. We measured a series of indicators to observe the levels of pulmonary arterial hypertension, pulmonary arteriole remodeling, and right ventricular remodeling. We assessed the activation of p38 mitogen-activated protein kinase (MAPK) in the pulmonary arteriole walls and pulmonary tissue homogenates using immunohistochemistry and western blot analyses, respectively. The matrix metalloproteinase- (MMP-) 9 protein and mRNA levels in the pulmonary arteriole walls were measured using immunohistochemistry and in situ hybridization. Our results demonstrated that baicalin not only reduced p38 MAPK activation in both the pulmonary arteriole walls and tissue homogenates but also downregulated the protein and mRNA expression levels of MMP-9 in the pulmonary arteriole walls. This downregulation was accompanied by the attenuation of pulmonary hypertension, arteriole remodeling, and right ventricular remodeling. These results suggest that baicalin may attenuate pulmonary hypertension and cor pulmonale, which are induced by chronic hypoxia, by downregulating the p38 MAPK/MMP-9 pathway.

Lentil consumption reduces resistance artery remodeling and restores arterial compliance in the spontaneously hypertensive rats

We previously established that lentils were able to significantly attenuate the development of hypertension in spontaneously hypertensive rats (SHRs), but the mechanism was not investigated. The current study was therefore designed to examine the effect of lentils on arterial function in relation to arterial stiffness, lipid biochemistry and activation of select aortic proteins. Seventeen-week-old male SHRs were randomly assigned to groups (n=10/group) fed (a) 30% w/w green lentils, (b) 30% red lentils, (c) 30% mixed lentils (red and green) or (d) no lentils for 8 weeks. Normotensive Wistar Kyoto (WKY) groups (n=10/group) received either the mixed lentil or no lentil diet. Blood pressure, pulse wave velocity and serum lipids were measured at baseline and 8 weeks, while pressure myography, arterial morphology and aortic proteins were measured after termination. There were no dietary-related changes in pulse wave velocity or blood pressure for any SHR or WKY group. Low-density lipoprotein cholesterol and high-density lipoprotein cholesterol were significantly lower in only SHR red lentil and WKY mixed lentil groups compared to their controls. The lentil diets reduced the media:lumen ratio of SHRs relative to control-fed SHRs but had no effect on WKYs. Both red and green lentils reduced arterial stiffness of SHRs but not WKYs. SHR lentil groups showed lower aortic p38 mitogen-activated protein kinase (p38MAPK) phosphorylation, thus implying that p38MAPK activation is suppressed with lentil feeding. Lentil-based diets suppress pathological vascular remodeling in SHRs, while green lentils maintain the vascular function of SHRs similar to normotensive WKYs despite the presence of high blood pressure.

Mutually Supportive Mechanisms of Inflammation and Vascular Remodeling

Chronic inflammation is often accompanied by angiogenesis, the development of new blood vessels from existing ones. This vascular response is a response to chronic hypoxia and/or ischemia, but is also contributory to the progression of disorders including atherosclerosis, arthritis, and tumor growth. Proinflammatory and proangiogenic mediators and signaling pathways form a complex and interrelated network in these conditions, and many factors exert multiple effects. Inflammation drives angiogenesis by direct and indirect mechanisms, promoting endothelial proliferation, migration, and vessel sprouting, but also by mediating extracellular matrix remodeling and release of sequestered growth factors, and recruitment of proangiogenic leukocyte subsets. The role of inflammation in promoting angiogenesis is well documented, but by facilitating greater infiltration of leukocytes and plasma proteins into inflamed tissues, angiogenesis can also propagate chronic inflammation. This review examines the mutually supportive relationship between angiogenesis and inflammation, and considers how these interactions might be exploited to promote resolution of chronic inflammatory or angiogenic disorders.

miR-21-mediated decreased neutrophil apoptosis is a determinant of impaired coronary collateral growth in metabolic syndrome

Coronary collateral growth (CCG) is impaired in metabolic syndrome. microRNA-21 (miR-21) is a proproliferative and antiapoptotic miR, which we showed to be elevated in metabolic syndrome. Here we investigate whether impaired CCG in metabolic syndrome involved miR-21-mediated aberrant apoptosis. Normal Sprague-Dawley (SD) and metabolic syndrome [J. C. Russel (JCR)] rats underwent transient, repetitive coronary artery occlusion [repetitive ischemia (RI)]. Antiapoptotic Bcl-2, phospho-Bad, and Bcl-2/Bax dimers were increased on days 6 and 9 RI, and proapoptotic Bax and Bax/Bax dimers and cytochrome-c release concurrently decreased in JCR versus SD rats. Active caspases were decreased in JCR versus SD rats (~50%). Neutrophils increased transiently on day 3 RI in the collateral-dependent zone of SD rats but remained elevated in JCR rats, paralleling miR-21 expression. miR-21 downregulation by anti-miR-21 induced neutrophil apoptosis and decreased Bcl-2 and Bcl-2/Bax dimers (~75%) while increasing Bax/Bax dimers, cytochrome-c release, and caspase activation (~70, 400, and 400%). Anti-miR-21 also improved CCG in JCR rats (~60%). Preventing neutrophil infiltration with blocking antibodies resulted in equivalent CCG recovery, confirming a major role for deregulated neutrophil apoptosis in CCG impairment. Neutrophil and miR-21-dependent CCG inhibition was in significant part mediated by increased oxidative stress. We conclude that neutrophil apoptosis is integral to normal CCG and that inappropriate prolonged miR-21-mediated survival of neutrophils plays a major role in impaired CCG, in part via oxidative stress generation.

Management of hepatocellular carcinoma: Predictive value of immunohistochemical markers for postoperative survival

Hepatocellular carcinoma (HCC) accounts for over 90% of all primary liver cancers. With an ever increasing incidence trend year by year, it has become the third most common cause of death from cancer worldwide. Hepatic resection is generally considered to be one of the most effective therapies for HCC patients, however, there is a high risk of recurrence in postoperative HCC. In clinical practice, there exists an urgent need for valid prognostic markers to identify patients with prognosis, hence the importance of studies on prognostic markers in improving the prediction of HCC prognosis. This review focuses on the most promising immunohistochemical prognostic markers in predicting the postoperative survival of HCC patients.

Elastin-derived peptides stimulate trophoblast migration and invasion: a positive feedback loop to enhance spiral artery remodelling

Elastin breakdown in the walls of uterine spiral arteries during early pregnancy facilitates their transformation into dilated, high-flow, low-resistance channels. Elastin-derived peptides (EDP) can influence cell migration, invasion and protease activity, and so we hypothesized that EDP released during elastolysis promote extravillous trophoblast (EVT) invasion and further elastin breakdown. Treatment of the trophoblast cell line SGHPL4 with the elastin-derived matrikine VGVAPG (1 μg/ml) significantly increased total elastase activity, promoted migration in a wound healing assay and increased invasion through Matrigel-coated transwells compared with vehicle control (0.1% DMSO) or the scrambled sequence VVGPGA. Furthermore, treatment of first-trimester placental villous explants with this EDP significantly increased both the area of trophoblast outgrowth and distance of migration away from the villous tips. Primary first-trimester cytotrophoblast exposed to VGVAPG (1 μg/ml) for 30 min showed increased phosphorylation of endothelial nitric oxide synthase and activation of the mitogen activated protein kinase pathway, events also associated with tumour cell migration and invasion. These in vitro observations suggest liberation of bioactive EDP during induction of elastolysis in the uterine spiral arteries may orchestrate a positive feedback loop that promotes EVT invasion and further elastin breakdown, contributing to the process of vascular remodelling.

Role of MMP2 and MMP9 in TRPV4-induced lung injury

Ca(2+) entry through transient receptor potential vanilloid 4 (TRPV4) results in swelling, blebbing, and detachment of the epithelium and capillary endothelium in the intact lung. Subsequently, increased permeability of the septal barrier and alveolar flooding ensue. In this study, we tested the hypothesis that TRPV4 activation provides a Ca(2+) source necessary for proteolytic disruption of cell-cell or cell-matrix adhesion by matrix metalloproteinases (MMPs) 2 and 9, thus increasing septal barrier permeability. In our study, C57BL/6 or TRPV4(-/-) mouse lungs were perfused with varying doses of the TRPV4 agonist GSK-1016790A (Sigma) and then prepared for Western blot. Lung injury, assessed by increases in lung wet-to-dry weight ratios and total protein levels in the bronchoalveolar lavage fluid, was increased in a dose-dependent fashion in TRPV4(+/+) but not TRPV4(-/-) lungs. In concert with lung injury, we detected increased active MMP2 and MMP9 isoforms, suggesting that TRPV4 can provide the Ca(2+) source necessary for increased MMP2/9 activation. Furthermore, tissue inhibitor of metalloproteinases (TIMP) 2 levels in the TRPV4-injured lungs were decreased, suggesting that TRPV4 activation increases the availability of these active MMPs. We then determined whether MMP2 and MMP9 mediate TRPV4-induced lung injury. Pharmacological blockade (SB-3CT, 1 μM; Sigma) of MMP2 and MMP9 resulted in protection against TRPV4-induced lung injury. We conclude that TRPV4 activation and the subsequent Ca(2+) transient initiates a rapid cascade of events leading to release and activation of the gelatinase MMPs, which then contribute to lung injury.

miR-21 normalizes vascular smooth muscle proliferation and improves coronary collateral growth in metabolic syndrome

Inadequate cell proliferation is considered a major causative factor for impaired coronary collateral growth (CCG). Proangiogenic growth factors (GFs) stimulate cell proliferation, but their administration does not promote CCG in patients. These GFs are increased in patients with metabolic syndrome and in animal models, where CCG is impaired. Here, we investigated whether excessive cell proliferation underlies impaired CCG in metabolic syndrome. Normal [Sprague-Dawley (SD)] and metabolic syndrome [James C. Russell (JCR)] rats underwent repetitive ischemia (RI; transient, repetitive coronary artery occlusion and myocardial ischemia). We have shown that CCG was maximal at d 9 of RI in SD rats but did not occur in JCR rats. The increase in cell proliferation (PCNA, Ki-67, cyclin A, phospho- cdc2, p21Waf, p27Kip) was transient (∼4-fold, d 3 RI) in SD rats but greater and sustained in JCR rats (∼8- to 6-fold, d 3-9 RI). In JCR rats, this was associated with increased and sustained miR-21 expression and accumulation of proliferating synthetic vascular smooth muscle cells in the lumen of small arterioles, which failed to undergo outward expansion. Administration of anti-miR-21 blocked RI-induced cell proliferation and significantly improved CCG in JCR rats (∼60%). miR-21-dependent excessive cell proliferation in the later stages of collateral remodeling correlates with impaired CCG in metabolic syndrome.

A device for performing automated balloon catheter inflation ischemia studies

Coronary collateral growth (arteriogenesis) is a physiological adaptive response to transient and repetitive occlusion of major coronary arteries in which small arterioles (native collaterals) with minimal to no blood flow remodel into larger conduit arteries capable of supplying adequate perfusion to tissue distal to the site of occlusion. The ability to reliably and reproducibly mimic transient, repetitive coronary artery occlusion (ischemia) in animal models is critical to the development of therapies to restore coronary collateral development in type II diabetes and the metabolic syndrome. Current animal models for repetitive coronary artery occlusion implement a pneumatic occluder (balloon) that is secured onto the surface of the heart with the suture, which is inflated manually, via a catheter connected to syringe, to effect occlusion of the left anterior descending coronary artery (LAD). This method, although effective, presents complications in terms of reproducibility and practicality. To address these limitations, we have designed a device for automated, transient inflation of balloon catheters in coronary artery occlusion models. This device allows repeated, consistent inflation (to either specified pressure or volume) and the capability for implementing very complex, month-long protocols. This system has significantly increased the reproducibility of coronary collateral growth studies in our laboratory, resulting in a significant decrease in the numbers of animals needed to complete each study while relieving laboratory personnel from the burden of extra working hours and enabling us to continue studies over periods when we previously could not. In this paper, we present all details necessary for construction and operation of the inflator. In addition, all of the components for this device are commercially available and economical (Table S1). It is our hope that the adoption of automated balloon catheter inflation protocols will improve the experimental reliability of transient ischemia studies at many research institutions.

PPARγ activation inhibits cerebral arteriogenesis in the hypoperfused rat brain

AIMS

PPARγ stimulation improves cardiovascular (CV) risk factors, but without improving overall clinical outcomes. PPARγ agonists interfere with endothelial cell (EC), monocyte and smooth muscle cell (SMC) activation, function and proliferation, physiological processes critical for arterial collateral growth (arteriogenesis). We therefore assessed the effect of PPARγ stimulation on cerebral adaptive and therapeutic collateral growth.

METHODS

In a rat model of adaptive cerebral arteriogenesis (3-VO), collateral growth and function were assessed (i) in controls, (ii) after PPARγ stimulation (pioglitazone 2.8 mg kg(-1); 10 mg kg(-1) compared with metformin 62.2 mg kg(-1) or sitagliptin 6.34 mg kg(-1)) for 21 days or (iii) after adding pioglitazone to G-CSF (40 μg kg(-1) every other day) to induce therapeutic arteriogenesis for 1 week. Pioglitazone effects on endothelial and SMC morphology and proliferation, monocyte activation and migration were studied.

RESULTS

PPARγ stimulation decreased cerebrovascular collateral growth and recovery of hemodynamic reserve capacity (CVRC controls: 12 ± 7%; pio low: -2 ± 9%; pio high: 1 ± 7%; metformin: 9 ± 13%; sitagliptin: 11 ± 12%), counteracted G-CSF-induced therapeutic arteriogenesis and interfered with EC activation, SMC proliferation, monocyte activation and migration.

CONCLUSION

Pharmacologic PPARγ stimulation inhibits pro-arteriogenic EC activation, monocyte function, SMC proliferation and thus adaptive as well as G-CSF-induced cerebral arteriogenesis. Further studies should evaluate whether this effect may underlie the CV risk associated with thiazolidinedione use in patients.

Molecular mechanisms associated with Angiotensin-converting enzyme-inhibitory peptide activity on vascular extracellular matrix remodeling

OBJECTIVE

This paper aimed to investigate the molecular mechanisms associated with angiotensin-converting enzyme (ACE)-inhibitory peptide activity involved in vascular extracellular matrix (ECM) remodeling. Therefore, changes in collagen fibers, elastic fibers and laminin were assessed in the left common carotid artery (LCCA).

METHODS

We selected 10-week-old male spontaneously hypertensive rats to study the expression levels of matrix metalloproteinases (MMPs), transforming growth factor, angiotensin (Ang) II and nuclear factor (NF)-p65 in the wall of carotid arteries.

RESULTS

Compared to the control group, laminin expression was significantly increased (p < 0.05) in the vascular endothelium of the LAP (a homemade ACE-inhibitory peptide, named by ourselves) group, whereas the percentage of elastic/collagen fibers in the LCCA vascular area was significantly decreased (p < 0.0001) in the LAP group. Immune blots of MMP-2, MMP-9, NF-p65 and AngII were significantly reduced in the LCCA wall in the LAP group.

CONCLUSION

Vascular ECM remodeling may be related to the inhibitory action of LAP on ECM deposition.

MicroRNA-124-3p inhibits cell migration and invasion in bladder cancer cells by targeting ROCK1

Background

Increasing evidence has suggested that dysregulation of certain microRNAs (miRNAs) may contribute to human disease including carcinogenesis and tumor metastasis in human. miR-124-3p is down-regulated in various cancers, and modulates proliferation and aggressiveness of cancer cells. However, the roles of miR-124-3p in human bladder cancer are elusive. Thus, this study was conducted to investigate the biological functions and its molecular mechanisms of miR-124-3p in human bladder cancer cell lines, discussing whether it has a potential to be a therapeutic biomarker of bladder cancer.

Methods

Three human bladder cancer cell lines and samples from ten patients with bladder cancer were analyzed for the expression of miR-124-3p by quantitative RT--PCR. Exogenetic overexpression of miR-124-3p was established by transfecting mimics into T24, UM-UC-3 and J82 cells, after that cell proliferation and cell cycle were assessed by MTT assay, flow cytometry and Colony-forming assay. Cell motility and invasion ability were evaluated by wound healing assay and transwell assay. Tissue microarray, and immunohistochemistry with antibodies against ROCK1, MMP2 and MMP9 was performed using the peroxidase and DAB methods. The target gene of miR-124-3p was determined by luciferase assays, quantitative RT--PCR and western blot. The regulation of epithelial-to-mesenchymal transition by miR-124-3p was analyzed by western blot.

Results

miR-124-3p is frequently down-regulated in bladder cancer both in three bladder cancer cell lines, T24, UM-UC-3, J82 and clinical samples. Overexpression of miR-124-3p induced G1-phase arrest in T24, UM-UC-3 and J82 cell lines and suppressed cell growth in colony-forming assay. miR-124-3p significantly repressed the capability of migration and invasion of bladder cancer cells. In addition, ROCK1 was identified as a new target of miR-124-3p. ROCK1, MMP2, MMP9 were up-regulated in bladder cancer tissues. Furthermore, we demonstrated miR-124-3p could inhibit bladder cancer cell epithelial mesenchymal transfer, and regulated the expression of c-Met, MMP2, MMP9.

Conclusions

miR-124-3p can repress the migration and invasion of bladder cancer cells via regulating ROCK1. Our data indicate that miR-124-3p could be a tumor suppressor and may have a potential to be a diagnostics or predictive biomarker in bladder cancer.

Impaired coronary collateral growth in the metabolic syndrome is in part mediated by matrix metalloproteinase 12-dependent production of endostatin and angiostatin

OBJECTIVE

We have previously shown that transient coronary artery occlusion stimulated coronary collateral growth (CCG) in healthy (Sprague Dawley) but not in metabolic syndrome (JCR:LA-cp [JCR] ) rats. Here, we sought to determine whether matrix metalloproteinases (MMPs) negatively regulate CCG in the metabolic syndrome via release of endostatin and angiostatin.

APPROACH AND RESULTS

Rats underwent transient, repetitive left anterior descending occlusion and resultant myocardial ischemia (RI) for 0 to 10 days. CCG was measured in the collateral-dependent and normal zones using microspheres, MMP activation by Western blot, and endostatin and angiostatin by ELISA on days 0, 3, 6, 9, or 10 of RI. Endostatin and angiostatin were increased in JCR but not in Sprague Dawley rats on days 6 and 9 of RI. Increased endostatin and angiostatin correlated with increased MMP12 (≈ 4-fold) activation in JCR but not in Sprague Dawley rats on days 6 and 9 of RI. Inhibition of MMP12 in JCR rats nearly completely blocked endostatin (≈ 85%) and angiostatin (≈ 90%) generation and significantly improved CCG (collateral-dependent zone flow was ≈ 66% of normal zone flow versus ≈ 12% for JCR RI).

CONCLUSIONS

Compromised CCG in the metabolic syndrome is, in large part, because of increased MMP12 activation and consequent increased generation of endostatin and angiostatin, which inhibits late-stage collateral remodeling.

Suppression of type I collagen in human scleral fibroblasts treated with extremely low-frequency electromagnetic fields

PURPOSE

To investigate the expression differences of type I collagen (COL1A1) and its underlying mechanisms in human fetal scleral fibroblasts (HFSFs) that were treated with conditioned medium from retinal pigment epithelial (RPE) cells under extremely low-frequency electromagnetic fields (ELF-EMFs).

METHODS

The ELF-EMFs used in this study were established by slidac and artificial coils. Growth of the treated HFSFs was evaluated by a cell-counting kit-8 assay. The expression of COL1A1 and matrix metalloproteinases-2 (MMP-2) in the treated HFSFs was detected by reverse transcription PCR (RT-PCR) and western blot, and the expression of transforming growth factor-β2 (TGF-β2) and basic fibroblast growth factor-2 (FGF-2) in RPE cells exposed to EMFs was detected by RT-PCR. The expression of COL1A1 and MMP-2 in HFSFs was further confirmed by immunofluorescence staining. Activation of extracellular signal-regulated kinase 1/2 (ERK1/2 also called p44/p42 mitogen-activated protein kinases [MAPK]) and p38 in HFSFs was measured by western blot.

RESULTS

We found that exposure to ELF-EMFs resulted in a decreased proliferation rate of HFSFs and that addition of RPE supernatant medium could enhance this effect. Compared with that of the control cells, a significant decrease in collagen synthesis was detected in HFSFs under ELF-EMFs. However, the expression of MMP-2 was upregulated, which could be further enhanced via an RPE supernatant additive. The activities of ERK1/2 and p38 were significantly increased in HFSFs exposed to ELF-EMFs, and this effect could be enhanced by RPE supernatant medium additive.

CONCLUSIONS

Our results suggested that ELF-EMFs can inhibit the expression of type I collagen in HFSFs and contribute to the remodeling of the sclera.

MicroRNA-145 restores contractile vascular smooth muscle phenotype and coronary collateral growth in the metabolic syndrome

OBJECTIVE

Transient, repetitive occlusion stimulates coronary collateral growth (CCG) in normal animals. Vascular smooth muscle cells (VSMCs) switch to synthetic phenotype early in CCG, then return to contractile phenotype. CCG is impaired in the metabolic syndrome. We determined whether impaired CCG was attributable to aberrant VSMC phenotypic modulation by miR-145-mediated mechanisms, and whether restoration of physiological miR-145 levels in metabolic syndrome (JCR rat) improved CCG.

APPROACH AND RESULTS

CCG was stimulated by transient, repetitive left anterior descending artery occlusion and evaluated after 9 days by coronary blood flow measurements (microspheres). miR-145 was delivered to JCR VSMCs via adenoviral vector (miR-145-Adv). In JCR rats, miR-145 was decreased late in CCG (≈ 2-fold day 6; ≈ 4-fold day 9 versus SD), which correlated with decreased expression of smooth muscle-specific contractile proteins (≈ 5-fold day 6; ≈ 10-fold day 9 versus SD), indicative of VSMCs' failure to return to the contractile phenotype late in CCG. miR-145 expression in JCR rats (miR-145-Adv) on days 6 to 9 of CCG completely restored VSMCs contractile phenotype and CCG (collateral/normal zone flow ratio was 0.93 ± 0.09 JCR+miR-145-Adv versus 0.12 ± 0.02 JCR versus 0.87 ± 0.02 SD).

CONCLUSIONS

Restoration of VSMC contractile phenotype through miR-145 delivery is a highly promising intervention for restoration of CCG in the metabolic syndrome.

Macrophages in collateral arteriogenesis

Arteriosclerotic vascular disease is the most common cause of death and a major cause of disability in the developed world. Adverse outcomes of arteriosclerotic vascular disease are related to consequences of tissue ischemia and necrosis affecting the heart, brain, limbs, and other organs. Collateral artery growth or arteriogenesis occurs naturally and can help restore perfusion to ischemic tissues. Understanding the mechanisms of collateral artery growth may provide therapeutic options for patients with ischemic vascular disease. In this review, we examine the evidence for a role of monocytes and macrophages in collateral arteriogenesis.

Why is coronary collateral growth impaired in type II diabetes and the metabolic syndrome?

Type II diabetes and the metabolic syndrome are strong predictors of severity of occlusive coronary disease and poorer outcomes of coronary revascularization therapies. Coronary collateral growth can provide an alternative or accessory pathway of revascularization. However, collateral growth is impaired in type II diabetes and the metabolic syndrome. Although many factors necessary for collateral growth are known and many interventions have shown promising results in animal studies, not a single attempt to induce coronary collateral growth in human clinical trials has led to satisfactory results. Accordingly, the first part of this review outlines the known deleterious effects of diabetes and the metabolic syndrome on factors necessary for collateral growth, including pro-angiogenic growth factors, endothelial function, the redox state of the coronary circulation, intracellular signaling, leukocytes and bone marrow-derived progenitors cells. The second section highlights the gaps in our current knowledge of how these factors interact with the radically altered environment of the coronary circulation in diabetes and the metabolic syndrome. The interplay between these pathologies and inadequately explored areas related to the temporal regulation of collateral remodeling and the roles of the extracellular matrix, vascular cell phenotype and pro-inflammatory cytokines are emphasized with implications to development of efficient therapies.