Prevention of abdominal aortic aneurysms by simultaneous inhibition of NFkappaB and ets using chimeric decoy oligonucleotides in a rabbit model

The decoy oligodeoxynucleotide against HIF-1α and STAT5 ameliorates atopic dermatitis-like mouse model

Atopic dermatitis (AD) is a common inflammatory skin disease caused by an immune disorder. Mast cells are known to be activated and granulated to maintain an allergic reaction, including rhinitis, asthma, and AD. Although hypoxia-inducible factor-1 alpha (HIF-1α) and signal transducer and activator of transcription 5 (STAT5) play crucial roles in mast cell survival and granulation, their effects need to be clarified in allergic disorders. Thus, we designed decoy oligodeoxynucleotide (ODN) synthetic DNA, without open ends, containing complementary sequences for HIF-1α and STAT5 to suppress the transcriptional activities of HIF-1α and STAT5. In this study, we demonstrated the effects of HIF-1α/STAT5 ODN using AD-like in vivo and in vitro models. The HIF-1α/STAT5 decoy ODN significantly alleviated cutaneous symptoms similar to AD, including morphology changes, immune cell infiltration, skin barrier dysfunction, and inflammatory response. In the AD model, it also inhibited mast cell infiltration and degranulation in skin tissue. These results suggest that the HIF-1α/STAT5 decoy ODN ameliorates the AD-like disorder and immunoglobulin E (IgE)-induced mast cell activation by disrupting HIF-1α/STAT5 signaling pathways. Taken together, these findings suggest the possibility of HIF-1α/STAT5 as therapeutic targets and their decoy ODN as a potential therapeutic tool for AD.

Effects of Mechanical Stress on Endothelial Cells In Situ and In Vitro

Endothelial cells lining blood vessels are essential for maintaining vascular homeostasis and mediate several pathological and physiological processes. Mechanical stresses generated by blood flow and other biomechanical factors significantly affect endothelial cell activity. Here, we review how mechanical stresses, both in situ and in vitro, affect endothelial cells. We review the basic principles underlying the cellular response to mechanical stresses. We also consider the implications of these findings for understanding the mechanisms of mechanotransducer and mechano-signal transduction systems by cytoskeletal components.

Degeneration and Regeneration of Smooth Muscle Cells in Two Different Abdominal Aortic Aneurysm Models in Rabbits

BACKGROUND

We aimed to investigate the formation and self-healing process of rabbit abdominal aortic aneurysm (AAA) by focus on the degeneration and regeneration of smooth muscle cells (SMCs) in elastase-induced AAA model and enlarging AAA model in rabbits.

METHODS

Sixty rabbits were equally divided into 2 aneurysm groups (Group A and Group B). Rabbits received a 10-min incubation of elastase in Group A (10 units/µL) and Group B (1 unit/µL). Rabbits underwent aortic stenosis above the incubated segment in Group B. Aortic diameter was measured and rabbits were sacrificed for histopathological and immunohistochemical studies.

RESULTS

The incubated aorta dilated immediately and ran up to maxima by day 21 in Group A. All aneurysms formed by day 21 and enlarged progressively in Group B. SMCs content, elastin content and intima-media thickness decreased significantly by day 0 in Group A. SMCs and elastic fibers were destroyed gradually in Group B, however, SMCs content was significantly lower than Group A by day 70. Intimal thickness increased significantly by day 70 in the Aneurysm groups. MMP2 maintained moderate expression in Group A, which decreased significantly by day 3 in Group B. MMP9 and RAM11 expressions were higher by day 1, but decreased significantly by day 3 in Group B.

CONCLUSIONS

Irreversible degeneration of SMCs is critical to a rapid formation of elastase-induced rabbit AAA model, and SMCs excessive regeneration accounts for the selfhealing process. SMCs degradation and regeneration remain relatively stable in an enlarging AAA model. SMCs should be the key target for studying the mechanism of AAA and intervention therapy.

Harnessing the Therapeutic Potential of Decoys in Non-Atherosclerotic Cardiovascular Diseases: State of the Art

Cardiovascular disease (CVD) is the main cause of global death, highlighting the fact that conventional therapeutic approaches for the treatment of CVD patients are insufficient, and there is a need to develop new therapeutic approaches. In recent years, decoy technology, decoy oligodeoxynucleotides (ODN), and decoy peptides show promising results for the future treatment of CVDs. Decoy ODN inhibits transcription by binding to the transcriptional factor, while decoy peptide neutralizes receptors by binding to the ligands. This review focused on studies that have investigated the effects of decoy ODN and decoy peptides on non-atherosclerotic CVD.

Estimation of Selected Minerals in Aortic Aneurysms-Impaired Ratio of Zinc to Lead May Predispose?

The objective of this study was to estimate the content of copper, zinc, selenium, cadmium, and lead in the tissue of patients with aortic aneurysms. Molar ratio of Cu/Zn and antioxidant micronutrients to toxic elements was also calculated. A total of 108 patients: 47 with abdominal aortic aneurysm (AAA), 61 patients with thoracic aortic aneurysm (TAA), and a control group of 20 abdominal aortic (AA) and 20 thoracic aortic (TA) wall samples from the deceased were studied. The concentrations of mineral components in the tissue samples were determined by the AAS method. The average concentration of Cu in the aortic wall of patients with TAA was significantly lower than in the aortic wall samples of healthy people. The mean concentration of Zn in the aortic wall of patients with AAA and TAA was significantly lower than in the control group samples. Cu/Zn ratio was significantly higher in AAA patients than in control group which indicates a greater role of oxidative stress and inflammatory process in this type of aneurysm. The concentration of Se was significantly decreased in TAA patients compared with the control group; in turn, the concentration of Pb was increased in this group of patients. We observed significantly lower Cu/Pb ratio in TAA patients than in control group, whereas Zn/Pb ratio was significantly lower comparing with control samples in both types of aneurysms. In the examined aneurysms, we have shown the differences in concentrations of mineral components compared with the control tissues. The Zn concentration was decreased in both AAA and TAA samples. Impaired ratio of Zn to Pb may predispose to aortic aneurysms.

Cellular signaling in Abdominal Aortic Aneurysm

Abdominal aortic aneurysms (AAAs) are highly lethal cardiovascular diseases without effective medications. However, the molecular and signaling mechanisms remain unclear. A series of pathological cellular processes have been shown to contribute to AAA formation, including vascular extracellular matrix remodeling, inflammatory and immune responses, oxidative stress, and dysfunction of vascular smooth muscle cells. Each cellular process involves complex cellular signaling, such as NF-κB, MAPK, TGFβ, Notch and inflammasome signaling. In this review, we discuss how cellular signaling networks function in various cellular processes during the pathogenesis and progression of AAA. Understanding the interaction of cellular signaling networks with AAA pathogenesis as well as the crosstalk of different signaling pathways is essential for the development of novel therapeutic approaches to and personalized treatments of AAA diseases.

AEBP1 Promotes the Occurrence and Development of Abdominal Aortic Aneurysm by Modulating Inflammation via the NF-κB Pathway

AIM

Inflammation plays a significant role in the pathogenesis of human abdominal aortic aneurysm (AAA). AEBP1 can promote activation of the NF-κB pathway, subsequently affecting the expression of NF-κB target genes, including inflammatory cytokines and matrix metalloproteinases (MMPs). Our objective was to examine the role of AEBP1 in the development of AAA and characterize the underlying mechanism.

METHODS

ITRAQ, RT-PCR, western blot, immunohistochemistry, and ELISA were used to compare different experimental groups with the controls and to determine the differentially expressed genes. We generated an AAA model using porcine pancreatic elastase in Sprague-Dawley rats and silenced their AEBP1 in vivo by adenoviruses injected intra-adventitially. We also silenced or overexpressed AEBP1 in human vascular smooth muscle cells in vitro in the presence and in the absence of NF-κB inhibitor BAY 11-7082.

RESULTS

Proteome iTRAQ revealed a high expression of AEBP1 in AAA patients, which was verified by qRT-PCR, western blot, immunohistochemistry, and ELISA. The mean expression level of AEBP1 in AAA patients was higher than that in controls. Along with AEBP1 upregulation, we also verified mis-activation of NF-κB in human AAA samples. The in vivo studies indicated that AEBP1 knockdown suppressed AAA progression. Finally, the in vitro studies illustrated that AEBP1 promotes activation of the NF-κB pathway, subsequently upregulating pro-inflammatory factors and MMPs.

CONCLUSIONS

Our results indicate a role of AEBP1 in the pathogenesis of AAA and provide a novel insight into how AEBP1 causes the development of AAA by activating the NF-κB pathway.

Molecular Pharmacological Approaches for Treating Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is considered to be a potent life-threatening disorder in elderly individuals. Although many patients with a small AAA are detected during routine abdominal screening, there is no effective therapeutic option to prevent the progression or regression of AAA in the clinical setting. Recent advances in molecular biology have led to the identification of several important molecules, including microRNA and transcription factor, in the process of AAA formation. Regulation of these factors using nucleic acid drugs is expected to be a novel therapeutic option for AAA. Nucleic acid drugs can bind to target factors, mRNA, microRNA, and transcription factors in a sequence-specific fashion, resulting in a loss of function of the target molecule at the transcriptional or posttranscriptional level. Of note, inhibition of a transcription factor using a decoy strategy effectively suppresses experimental AAA formation, by regulating the expression of several genes associated with the disease progression. This review focuses on recent advances in molecular therapy of using nucleic acid drugs to treat AAA.

Hemodynamics and pathology of an enlarging abdominal aortic aneurysm model in rabbits

Hemodynamics may play an essential role in the initiation and progression of abdominal aortic aneurysm (AAA). We aimed to study the mechanism of self-healing process by the changes of hemodynamics and pathology in an enlarging AAA in rabbits. Seventy-two rabbits were randomly divided into three groups. Rabbits underwent extrinsic coarctation and received a 10-minute elastase incubation in Group A and Group B. Absorbable suture used in Group A was terminated by balloon dilation at week 4. Diameter was measured after 1, 3, 5, and 15 weeks, computational fluid dynamics analysis was performed at week 3 and week 15. Rabbits were sacrificed after 1, 5, and 15 weeks for pathological and quantitative studies. The higher velocity magnitude, intensified bulk flow and obvious vortex formation were observed in Group A at week 3 instead of week 15. Both low wall shear stress and high relative residence time increased in Group B, however, high oscillatory shear index had relatively less increase compared with Group A. Aortic diameter reached a plateau at 5 weeks in Group A, which was significantly lower than in week 15 in Group B. Intimal hyperplasia, intima-media thickness increased significantly in Group A at week 5, significantly higher than in week 15 in Group B. Marked destruction of elastin fibers and smooth muscle cells occurred at week 1, and increased significantly at week 15 in Group A. Aneurysm exhibited strong expression of matrix metalloproteinase 9 and mouse anti-rabbit macrophage 11 at week 1, and showed a tendency to decrease. Matrix metalloproteinase 2 expression decreased significantly in Group B at week 15 compared with week 5 and Group A. In conclusion, the self-healing of rabbit AAA may attributed to the regeneration of smooth muscle cells. The turbulence flow caused by coarctation is associated with continuous growth of rabbit AAA and prevents the self-healing phenomenon.

Rabbit aortic aneurysm model with enlarging diameter capable of better mimicking human aortic aneurysm disease

The self-healing phenomenon can be found in the elastase-induced abdominal aortic aneurysm (AAA) model, and an enlarging AAA model was successfully induced by coarctation. Unfortunately, aortic coarctation in these enlarging models is generally not found in human AAA disease. This study aimed to create an experiment model of enlarging AAA in rabbits to better mimic human aortic aneurysm disease. Eighty-four male New Zealand white rabbits were randomly divided into three equal groups: two aneurysm groups (A and B) and a SHAM group. Aneurysm group rabbits underwent extrinsic aortic stenosis below the right renal artery and received a 10-minute incubation of 60 μl elastase (1 unit/μl). Absorbable suture was used in Group A and nonabsorbable cotton thread was used in Group B. A sham operation was performed in the SHAM group. Aortic diameter was measured after 1, 3, 7, and 15 weeks; thereafter animals were sacrificed for histopathological, immunohistochemical and quantitative studies. Two rabbits died at 29 and 48 days, respectively, after operation in Group B. All aneurysms formed and enlarged progressively by 3 weeks in the Aneurysm groups. However, diameter enlargement in Group A was significantly lower than that in Group B at 7 weeks. Aneurysm groups developed intimal hyperplasia; intima-media thickness (IMT) increased significantly by week 7, and aortic media thickness and intima-media ratio (IMR) increased significantly by week 15. Marked destruction of elastin fibers and smooth muscle cells (SMCs) occurred 1 week later and increased progressively thereafter. Intimal hyperplasia and SMCs content in Group A increased significantly by week 15 compared with Group B. Aneurysm groups exhibited strong expression of matrix metalloproteinases 2 and 9 and RAM11 by week 1, and decreased progressively thereafter. In conclusion, this novel rabbit AAA model enlarges progressively without coarctation and is capable of better mimicking human aortic aneurysm disease.

The oral administration of clarithromycin prevents the progression and rupture of aortic aneurysm

OBJECTIVE

The pathogenesis of aortic aneurysm (AA) is associated with chronic inflammation in the aortic wall with increased levels of matrix metalloproteinases (MMPs). Clarithromycin (CAM) has been reported to suppresses MMP activity. In this study, we investigated whether CAM could prevent the formation and rupture of AA.

METHODS

Male apolipoprotein E-deficient mice (28-30 weeks of age) were infused with angiotensin II for 28 days. CAM (100 mg/kg/d) or saline (as a control) was administered orally to the mice every day (CAM group, n = 13; control group, n = 13). After the administration period, the aortic diameter, elastin content, macrophage infiltration, MMP levels, and levels of inflammatory cytokines, including nuclear factor κB (NF-κB), were measured.

RESULTS

The aortic diameter was significantly suppressed in the CAM group (P < .001). No rupture death was observed in the CAM group in contrast to five deaths (38%) in the control group (P < .01). CAM significantly suppressed the degradation of aortic elastin (56.3% vs 16.5%; P < .001) and decreased the infiltration of inflammatory macrophages (0.05 vs 0.16; P < .01). Compared with the controls, the enzymatic activity of MMP-2 and MMP-9 was significantly reduced in the CAM group (MMP-2, 0.15 vs 0.56 [P < .01]; MMP-9, 0.12 vs 0.60 [P < .01]), and the levels of interleukin 1β (346.6 vs 1066.0; P < .05), interleukin 6 (128.4 vs 346.2; P < .05), and phosphorylation of NF-κB were also decreased (0.3 vs 2.0; P < .01).

CONCLUSIONS

CAM suppressed the progression and rupture of AA through the suppression of inflammatory macrophage infiltration, a reduction in MMP-2 and MMP-9 activity, and the inhibition of elastin degradation associated with the suppression of NF-κB phosphorylation.

Transauricular intra-arterial and intravenous digital subtraction angiography for abdominal aortic aneurysm imaging in a rabbit model

Aim

The aim of this study was to evaluate transauricular digital subtraction angiography (DSA) as an alternative to conventional intra-arterial DSA for rabbit abdominal aortic aneurysm (AAA).

Materials and methods

AAA models were created in 8 New Zealand white rabbits by sewing vein patch. The diameters of aortic arteries were measured by DSA via ear vein and ear central artery. The common carotid artery (CCA) was exposed and cannulated for DSA as conventional angiography. Diameter size was measured and compared.

Results

Aortic diameters, tested by DSA via ear vein, ear central artery and CCA were 7.9 ± 1.2 mm, 7.8 ± 1.0 mm and 7.9 ± 1.1 mm respectively, with no significant differences. Angiography via CCA as standard procedure, correlation in aneurysm neck diameter was r = 0.93 for IVDSA and r = 0.96 for angiography via central artery (P < 0.01); Correlation in AAA diameter was r = 0.99 for IVDSA and r = 0.99 for angiography via central artery (P < 0.0001).

Conclusions

Transauricular DSA shows good correlation to conventional DSA, can be used repeatedly with less invasiveness, and suitable for rabbit AAA follow-up study.

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Correlations of DSA via ear vein and ear central artery to conventional DSA were good.

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Transauricular DSA shows good correlation to conventional DSA.

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Transauricular DSA can be used repeatedly with less invasiveness, and suitable for rabbit AAA follow-up study.

Genetic associations of intracranial aneurysm formation and sub-arachnoid hemorrhage

Risk factors for cerebral aneurysms typically include age, hypertension, smoking, and alcohol usage. However, the possible connection of aneurysms with genetic conditions such as Marfan's syndrome, polycystic kidney disease, and neurofibromatosis raises the question of possible genetic risk factors for aneurysm, and additionally, genetic risk factors for rupture. We conducted a literature review using the PubMed database for studies regarding genetic correlation with cerebral aneurysm formation as well as rupture from December 2008 to Jun 2015. Twenty-one studies related to IA formation and 10 concerning IA rupture that met our criteria were found and tabulated. The most studied gene and the strongest association was 9p21/CDKN2, which is involved in vessel wall remodelling. Other possible genes that may contribute to IA formation include EDNRA and SOX17; however, these factors were not studied as robustly as CDKN2. Multiple factors contribute to aneurysm formation and rupture and the contributions of blood flow dynamics and comorbidities as mentioned previously, cannot be ignored. While these elements are important to development and rupture of aneurysms, genetic influence may predispose certain patients to formation of aneurysms and eventual rupture.

Effect of Low-Pressurized Perfusion with Different Concentration of Elastase on the Aneurysm Formation Rate in the Abdominal Aortic Aneurysm Model in Rabbits

Establishing an animal model of abdominal aortic aneurysm (AAA) is the key to study the pathogenesis and the pathophysiological features of AAAs. We investigated the effects of low-pressurized perfusion with different concentrations of elastase on aneurysm formation rate in the AAA model. Fifty male New Zealand white rabbits were randomly divided into A, B, C, D, and E groups. 10 μL of normal saline was perfused into the abdominal aorta in group A and 1 U/mL, 10 U/mL, 100 U/mL, or 200 U/mL of elastase was, respectively, perfused for the other four groups. All the animals were perfused for 7 min. Doppler ultrasound examinations of the abdominal aorta were performed before surgery and on day 14 after surgery. The rabbits were sacrificed and the perfused segment of the abdominal aorta was observed visually and after staining. The aneurysm formation rate of group A, group B, group C, group D, and group E was, respectively, 0%, 0%, 33.3%, 102.5–146.8%, and 241.5–255.2%. The survival rate of five groups was 90%, 90%, 90%, 90%, and 40%, respectively. So, we concluded that low-pressurized perfusion with 100 U/mL of elastase can effectively establish AAAs in rabbits with a high aneurysm formation rate.

Zinc Prevents Abdominal Aortic Aneurysm Formation by Induction of A20-Mediated Suppression of NF-κB Pathway

Chronic inflammation and degradation of elastin are the main processes in the development of abdominal aortic aneurysm (AAA). Recent studies show that zinc has an anti-inflammatory effect. Based on these, zinc may render effective therapy for the treatment of the AAA. Currently, we want to investigate the effects of zinc on AAA progression and its related molecular mechanism. Rat AAA models were induced by periaortic application of CaCl₂. AAA rats were treated by daily intraperitoneal injection of ZnSO₄ or vehicle alone. The aorta segments were collected at 4 weeks after surgery. The primary rat aortic vascular smooth muscle cells (VSMCs) were stimulated with TNF-α alone or with ZnSO₄ for 3 weeks. The results showed that zinc supplementation significantly suppressed the CaCl₂-induced expansion of the abdominal aortic diameter, as well as a preservation of medial elastin fibers in the aortas. Zinc supplementation also obviously attenuated infiltration of the macrophages and lymphocytes in the aortas. In addition, zinc reduced MMP-2 and MMP-9 production in the aortas. Most importantly, zinc treatment significantly induced A20 expression, along with inhibition of the NF-κB canonical signaling pathway in vitro in VSMCs and in vivo in rat AAA. This study demonstrated, for the first time, that zinc supplementation could prevent the development of rat experimental AAA by induction of A20-mediated inhibition of the NF-κB canonical signaling pathway.

Andrographolide Ameliorates Abdominal Aortic Aneurysm Progression by Inhibiting Inflammatory Cell Infiltration through Downregulation of Cytokine and Integrin Expression

Abdominal aortic aneurysm (AAA), characterized by exuberant inflammation and tissue deterioration, is a common aortic disease associated with a high mortality rate. There is currently no established pharmacological therapy to treat this progressive disease. Andrographolide (Andro), a major bioactive component of the herbaceous plant Andrographis paniculata, has been found to exhibit potent anti-inflammatory properties by inhibiting nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) activity in several disease models. In this study, we investigated the ability of Andro to suppress inflammation associated with aneurysms, and whether it may be used to block the progression of AAA. Whereas diseased aortae continued to expand in the solvent-treated group, daily administration of Andro to mice with small aneurysms significantly attenuated aneurysm growth, as measured by the diminished expansion of aortic diameter (165.68 ± 15.85% vs. 90.62 ± 22.91%, P < 0.05). Immunohistochemistry analyses revealed that Andro decreased infiltration of monocytes/macrophages and T cells. Mechanistically, Andro inhibited arterial NF-κB activation and reduced the production of proinflammatory cytokines [CCL2, CXCL10, tumor necrosis factor α, and interferon-γ] in the treated aortae. Furthermore, Andro suppressed α4 integrin expression and attenuated the ability of monocytes/macrophages to adhere to activated endothelial cells. These results indicate that Andro suppresses progression of AAA, likely through inhibition of inflammatory cell infiltration via downregulation of NF-κB-mediated cytokine production and α4 integrin expression. Thus, Andro may offer a pharmacological therapy to slow disease progression in patients with small aneurysms.

Inhibitory effect of nuclear factor-κB decoy oligodeoxynucleotide on liver fibrosis through regulation of the epithelial-mesenchymal transition

The epithelial-mesenchymal transition (EMT) has been recognized to occur during embryonic development, fibrosis, and tumor metastasis. Nuclear factor (NF)-κB plays a central role in mediating the inflammation and wound-healing responses during liver fibrogenesis. However, the involvement of NF-κB during EMT in liver cells remains unidentified. To develop a therapeutic approach to EMT during liver fibrosis, we examined the inhibition of transcription factor NF-κB, using a decoy oligodeoxynucleotide (ODN) strategy in liver fibrosis in vitro and in vivo. NF-κB decoy ODN contains consensus binding sequences of the NF-κB-binding site. NF-κB decoy ODN effectively suppresses transforming growth factor-β(1)-induced EMT in AML12 murine hepatocytes. Liver fibrosis induced by CCl(4) administration was suppressed by NF-κB decoy ODN. Furthermore, NF-κB decoy ODN was shown to inhibit the EMT process in fibrotic liver in vivo. This study demonstrates the feasibility of NF-κB decoy ODN treatment for preventing liver fibrosis via EMT processes.

Different long-term outcomes of abdominal aortic aneurysm and intracranial aneurysm models: hemodynamic change may also play an essential role in the initiation and progression of abdominal aortic aneurysm in rabbits

Self-healing phenomenon was found in the periarterial elastase-induced abdominal aortic aneurysm (AAA) in rabbit. This kind of aneurysm model does not progress and heals spontaneously in the long term, which is quite different from the performance of AAA disease in human. In order to better mimic human AAA and overcome this shortcoming of traditional AAA model in rabbit, we studied the pathogenesis of cerebral aneurysm (CA) model in small animal, which shows an excellent long-term patency and progressive enlargement. We found that hemodynamic conditions, such as turbulence flow, high blood flow, and shear stress, play an important role in the formation and progression of CA. So, we hypothesize that hemodynamic change may also play an essential role in the initiation and progression of rabbit AAA, and self-healing will be overcome if hemodynamic condition changes by coarctation of infra-renal aorta after elastase incubation.

Novel biological strategies for treatment of wear particle-induced periprosthetic osteolysis of orthopaedic implants for joint replacement

Wear particles and by-products from joint replacements and other orthopaedic implants may result in a local chronic inflammatory and foreign body reaction. This may lead to persistent synovitis resulting in joint pain and swelling, periprosthetic osteolysis, implant loosening and pathologic fracture. Strategies to modulate the adverse effects of wear debris may improve the function and longevity of joint replacements and other orthopaedic implants, potentially delaying or avoiding complex revision surgical procedures. Three novel biological strategies to mitigate the chronic inflammatory reaction to orthopaedic wear particles are reported. These include (i) interference with systemic macrophage trafficking to the local implant site, (ii) modulation of macrophages from an M1 (pro-inflammatory) to an M2 (anti-inflammatory, pro-tissue healing) phenotype in the periprosthetic tissues, and (iii) local inhibition of the transcription factor nuclear factor kappa B (NF-κB) by delivery of an NF-κB decoy oligodeoxynucleotide, thereby interfering with the production of pro-inflammatory mediators. These three approaches have been shown to be viable strategies for mitigating the undesirable effects of wear particles in preclinical studies. Targeted local delivery of specific biologics may potentially extend the lifetime of orthopaedic implants.

Chronic inflammation in biomaterial-induced periprosthetic osteolysis: NF-κB as a therapeutic target

Biomaterial-induced tissue responses in patients with total joint replacement are associated with the generation of wear particles, which may lead to chronic inflammation and local bone destruction (periprosthetic osteolysis). Inflammatory reactions associated with wear particles are mediated by several important signaling pathways, the most important of which involves the transcription factor NF-κB. NF-κB activation is essential for macrophage recruitment and maturation, as well as the production of pro-inflammatory cytokines and chemokines such as TNF-α, IL-1β, IL-6 and MCP1. In addition, NF-κB activation contributes to osteoclast differentiation and maturation via RANK/RANKL signaling, which increases bone destruction and reduces bone formation. Targeting individual downstream cytokines directly (such as TNF-α or IL-1β) may not effectively prevent wear particle induced osteolysis. A more logical upstream therapeutic approach may be provided by direct modulation of the core IκB/IKKα/β/NF-κB signaling pathway in the local environment. However, the timing, dose and strategy for administration should be considered. Suppression of chronic inflammation via inhibition of NF-κB activity in patients with malfunctioning joint replacements may be an effective strategy to mitigate wear particle induced periprosthetic osteolysis.

Block decoys: transcription-factor decoys designed for in vitro gene regulation studies

Transcription-factor decoys are short synthetic oligodeoxynucleotides that sequester cognate transcription factors and prevent their binding at target promoters. Current methods of decoy formation have primarily been optimized for potential therapeutic applications. However, they are not ideally suited to in vitro investigations into multi-transcription factor-mediated processes that may require multiple regulatory elements to be inhibited in varying combinations. In this study we describe a novel method for chimeric decoy formation in which blocks containing discrete transcription factor binding sites are combined into circular molecules. Unlike currently available methods, block decoys allow rapid construction of chimeric decoys targeting multiple regulatory elements. Further, they enable fine-tuning of binding-site copy ratios within chimeras, allowing sophisticated control of the cellular transcriptional landscape. We show that block decoys are exonuclease-resistant and specifically inhibit expression from target binding sites. The potential of block decoys to inhibit multiple elements simultaneously was demonstrated using a chimeric decoy containing molar optimized ratios of three regulatory elements, NF-κB-RE, CRE, and E-box. The chimeric decoy inhibited expression from all three elements simultaneously at equivalent levels. The primary intended use of block decoys is in vitro gene regulation studies in which bespoke chimeras can be rapidly constructed and utilized to determine a promoter's functional regulation.

Development of a novel rabbit model of abdominal aortic aneurysm via a combination of periaortic calcium chloride and elastase incubation

Background

The purpose of this study was to introduce a novel, simple and effective technique for creating a reliable rabbit model of abdominal aortic aneurysm (AAA) via a combination of periaortic calcium chloride (CaCl₂) and elastase incubation.

Methods

Forty-eight New Zealand white rabbits were divided into four groups. The AAA model was developed via a 20-minute periaortic incubation of CaCl₂ (0.5 mol/L) and elastase (1 Unit/µL) in a 1.5-cm aortic segment (Group CE). A single incubation of CaCl₂ (Group C) or elastase (Group E) and a sham operation group (Sham Group) were used for the controls. Diameter was measured by serial digital subtraction angiography imaging on days 5, 15 and 30. Animals were sacrificed on day 5 and day 30 for histopathological and immunohistochemical studies.

Results

All animals in Group CE developed aneurysm, with an average dilation ratio of 65.3%±8.9% on day 5, 86.5%±28.7% on day 15 and 203.6%±39.1% on day 30. No aneurysm was found in Group C, and only one aneurysm was seen on day 5 in Group E. Group CE exhibited less intima-media thickness, endothelial recovery, elastin and smooth muscle cell (SMC) content, but stronger expression of matrix metalloproteinase-2, matrix metalloproteinase-9 and RAM11 compared to the controls.

Conclusions

The novel rabbit model of AAA created by using a combination of periaortic CaCl₂ and elastase incubation is simple and effective to perform and is valuable for elucidating AAA mechanisms and therapeutic interventions in experimental studies.

Performance of a modified rabbit model of abdominal aortic aneurysm induced by topical application of porcine elastase: 5-month follow-up study

OBJECTIVES

To modify the method for creating an abdominal aortic aneurysm in rabbits, and to study its performance.

MATERIALS AND METHODS

A total of 24 New Zealand white rabbits were induced topically with 10 μl of porcine elastase (0, 0.1, 5 and 10 units μl(-1)) to define the optimal concentration (groups A-D). Twelve aneurysms were induced with 10 units μl(-1) of 10 μl elastase to serve as a follow-up group (group E) to serve as a follow-up. A 1.5-cm aortic segment was isolated and induced with elastase solution for 30 min.

RESULTS

All animals in groups D and E developed AAA by day 5. Aneurysms in Group E were stable over 100 days. Partial destruction to disappearance of elastic lamellae and smooth muscle cells (SMCs) was seen in elastase-treated animals by day 5. Regenerated elastin and proliferated SMCs were present in group E. Matrix metalloproteinases 2 and 9 and RAM11 showed strong expression in group D, but expression decreased in group E after day 15.

CONCLUSIONS

The rabbit AAA model induced via topical application of porcine elastase at 10 units μl(-1) for 30 min appears easy and simple, with shorter induction and more rapid aortic dilation. The model is stable over 100 days and is useful to study the formation and progress of AAAs.

Effects of chimeric decoy oligodeoxynucleotide in the regulation of transcription factors NF-κB and Sp1 in an animal model of atherosclerosis

Atherosclerosis is a multifactorial and progressive disease in which the inflammatory reaction and inflammation-related factors play important roles at all stages. Modulation of NF-κB and Sp1 expression may be important targets for the prevention and treatment of atherosclerotic vascular disease. To develop a novel therapeutic approach in atherosclerosis, we examined the simultaneous suppression of the transcription factors NF-κB and Sp1 which regulate inflammation. We employed chimeric decoy oligodeoxynucleotide (ODN) containing the consensus of NF-κB and Sp1-binding sites to suppress these transcription factors simultaneously and to test chimeric decoy for anti-atherogenic effects in an atherogenic diet-induced atherosclerotic mouse model with inflammatory stimulation. C57BL/6 mice were fed with an atherogenic diet (15% fat, 1.25% cholesterol and 0.5% cholic acid) for 12 weeks to induce atherosclerosis; lipopolysaccharide (LPS, 2 mg/kg) was intraperitoneally injected in the first week of study to simulate underlying infectious burden during development of atherosclerosis. Decoy ODNs were injected into tail vein at 2, 4, 6, 8, 10 and 12 weeks after only three LPS injections in mice fed the atherogenic diet. Chimeric decoy ODN alleviated atherosclerotic changes and reduced serum cholesterol and inflammatory cytokines. In accordance with these results, the expressions of atherosclerotic markers were inhibited by chimeric decoy ODN. Chimeric decoy ODN modulates multiple pathogenic aspects of an atherogenic diet-induced atherosclerosis with inflammatory stimulation: hypercholesterolaemia and inflammation. Therefore, this study demonstrates the efficacy of chimeric decoy ODN on atherosclerosis with immunological complication.

Regression of intracranial aneurysms by simultaneous inhibition of nuclear factor-κB and Ets with chimeric decoy oligodeoxynucleotide treatment

BACKGROUND

Despite a high mortality and morbidity of subarachnoid hemorrhage due to an intracranial aneurysm (IA), there is no effective medical treatment to prevent the rupture of IAs. Recent studies have revealed the involvement of the transactivation of proinflammatory genes by nuclear factor-κB (NF-κB) and Ets-1 in the pathogenesis of IA formation and enlargement.

OBJECTIVE

To examine the regressive effect of chimeric decoy oligodeoxynucleotides (ODNs), which simultaneously inhibit NF-κB and Ets-1, on IA development in the rat model.

METHODS

One month after IA induction, rats were treated with NF-κB decoy ODNs or chimeric decoy ODNs. Size, media thickness, macrophage infiltration, and collagen biosynthesis in IA walls were analyzed in both groups.

RESULTS

The treatment with chimeric decoy ODNs decreased IA size and thickened IA walls of preexisting IAs induced in the rat model, although the treatment with NF-κB decoy ODNs failed to regress preexisting IAs. Chimeric decoy ODN-treated rats exhibited decreased expression of monocyte chemotactic protein-1 and macrophage infiltration in IA walls. In addition, decreased collagen biosynthesis in IA walls was ameliorated in the chimeric decoy ODN-treated group.

CONCLUSION

The results suggest the possibility of a minimally invasive molecular therapy targeting the inhibition of NF-κB and ets-1 for IAs in humans.

Pathogenesis of abdominal aortic aneurysms: role of nicotine and nicotinic acetylcholine receptors

Inflammation, proteolysis, smooth muscle cell apoptosis, and angiogenesis have been implicated in the pathogenesis of abdominal aortic aneurysms (AAAs), although the well-defined initiating mechanism is not fully understood. Matrix metalloproteinases (MMPs) such as MMP-2 and -9 and other proteinases degrading elastin and extracellular matrix are the critical pathogenesis of AAAs. Among the risk factors of AAAs, cigarette smoking is an irrefutable one. Cigarette smoke is practically involved in various aspects of the AAA pathogenesis. Nicotine, a major alkaloid in tobacco leaves and a primary component in cigarette smoke, can stimulate the MMPs expression by vascular SMCs, endothelial cells, and inflammatory cells in vascular wall and induce angiogenesis in the aneurysmal tissues. However, for the inflammatory and apoptotic processes in the pathogenesis of AAAs, nicotine seems to be moving in just the opposite direction. Additionally, the effects of nicotine are probably dose dependent or associated with the exposure duration and may be partly exerted by its receptors—nicotinic acetylcholine receptors (nAChRs). In this paper, we will mainly discuss the pathogenesis of AAAs involving inflammation, proteolysis, smooth muscle cell apoptosis and angiogenesis, and the roles of nicotine and nAChRs.

Mast cells: important players in the orchestrated pathogenesis of abdominal aortic aneurysms

Mast cells (MCs) regulate inflammation and immunity. Their granular content includes heparin, histamine, and several enzymes (tryptase, chymase, carboxypeptidase, and cathepsin G). In addition, activated MCs synthesize and release eicosanoids and a large number of cytokines and chemokines. Recent findings suggest a role of MCs in abdominal aortic aneurysms (AAAs) in humans, where they are found in the media and adventitia. Experimentally induced AAA in MC-deficient animals and animals treated with MC inhibitors demonstrate that MCs are involved in the pathogenesis of AAA via several different mechanisms. MC-dependent activation of metalloproteinases and the renin-angiotensin system, contribution to smooth muscle cell apoptosis, and release of proteolytic enzymes are some key examples. Human studies indicate that MCs are the main source of cathepsin G in AAAs and contribute to activation of the renin-angiotensin system via chymase and cathepsin G. Activated MCs also contribute to neovascularization, inflammation, and atherosclerosis, all hallmarks of AAA. Thus, we may envision that MC stabilizing agents, as well as leukotriene receptor antagonists and histamine receptor blockers already in clinical use for treatment of other diseases, could also be tested for their efficacy in preventing development and growth of AAA.

Experimental models of abdominal aortic aneurysms

Despite being a leading cause of death in the West, the pathophysiology of abdominal aortic aneurysms (AAA) is still incompletely understood. Pharmacotherapy to reduce the growth of small AAAs is limited and techniques for repairing aneurysms continue to evolve. Experimental models play a key role in AAA research, as they allow a detailed evaluation of the pathogenesis of disease progression. This review focuses on in vivo experimental models, which have improved our understanding of the potential mechanisms of AAA development and contributed to the advancement of new treatments.

Salsalate may have broad utility in the prevention and treatment of vascular disorders and the metabolic syndrome

In the high proportion of vascular disorders associated with excessive oxidative stress and production of pro-inflammatory cytokines, activation of NF-kappaB plays a key pathogenic role. Thus, there is considerable evidence that NF-kappaB is a mediator of atherogenesis, plaque destabilization, ischemia-reperfusion damage, cardiac remodeling, atrial fibrillation, and aneurysm formation and rupture; some studies suggest that it may also play a role in the microvascular complications of diabetes. I kappaB kinase-beta (IKK beta) is the upstream kinase that appears to be primarily responsible for NF-kappaB activation in these disorders; moreover, chronic IKK beta activation plays a prominent role in induction of insulin resistance in the metabolic syndrome. Salicylate inhibits IKK beta in concentrations that are achievable with dose schedules traditionally used in treating rheumatoid arthritis (3-4.5 g daily); indeed, this is likely to be the mechanism responsible for salicylate's utility in this disorder. Salicylate, unlike aspirin, is only a very weak, reversible inhibitor of cyclooxygenase in clinical doses, and thus is not associated with the potentially dangerous side effects seen with NSAIDs; fully reversible ototoxicity, the dose-limiting side effect in salicylate therapy, can be avoided in most patients by dosage adjustment. Hence, it is proposed that salicylate may have practical utility in the prevention or management of a wide range of vascular disorders as well as of metabolic syndrome and diabetes; its efficacy in these regards would likely be complemented by effective antioxidant measures, which would lessen the stimulus to NF-kappaB activation while providing benefits independent of NF-kappaB activity. Salsalate, consisting of two salicylate molecules united by an ester bond, is a venerable drug that may be the best tolerated delivery vehicle for salicylate. Appropriate rodent studies should pave the way for clinical trials with salsalate in patients at vascular risk.

Risk factors for early recurrence after inguinal hernia repair

Background

Family history, male gender and age are significant risk factors for inguinal hernia disease. Family history provides evidence for a genetic trait and could explain early recurrence after inguinal hernia repair despite technical advance at least in a subgroup of patients. This study evaluates if age and family history can be identified as risk factors for early recurrence after primary hernia repair.

Methods

We performed an observational cohort study for 75 patients having at least two recurrent hernias. The impact of age, gender and family history on the onset of primary hernias, age at first recurrence and recurrence rates was investigated.

Results

44% (33/75) of recurrent hernia patients had a family history and primary as well as recurrent hernias occurred significantly earlier in this group (p = 0.04). The older the patients were at onset the earlier they got a recurrent hernia. Smoking could be identified as on additional risk factor for early onset of hernia disease but not for hernia recurrence.

Conclusion

Our data reveal an increased incidence of family history for recurrent hernia patients when compared with primary hernia patients. Patients with a family history have their primary hernias as well as their recurrence at younger age then patients without a family history. Though recurrent hernia has to be regarded as a disease caused by multiple factors, a family history may be considered as a criterion to identify the risk for recurrence before the primary operation.

Binding sites for ETS family of transcription factors dominate the promoter regions of differentially expressed genes in abdominal aortic aneurysms

BACKGROUND

Previously, we identified 3274 distinct differentially expressed genes in abdominal aortic aneurysm (AAA) tissue compared with nonaneurysmal controls. As transcriptional control is responsible for these expression changes, we sought to find common transcriptional elements in the promoter regions of the differentially expressed genes.

METHODS AND RESULTS

We analyzed the up- and downregulated gene sets with Whole Genome rVISTA to determine the transcription factor (TF) binding sites overrepresented in the 5-kb promoter regions of the 3274 genes. The downregulated gene set yielded 144 TF binding sites that were overrepresented in the subset when compared with the entire genome. In contrast, the upregulated gene set yielded only 13 distinct overrepresented TF binding sites. Interestingly, as classified by TRANSFAC, 8 of the 13 TFs binding to these regions belong to the ETS family. Additionally, nuclear factor kB and its subunits p50 and p65 showed enrichment. Immunohistochemical analyses of 10 TFs from the upregulated set showed 9 to be present in AAA tissue. Based on gene ontology analysis of biological process categories of the upregulated target genes of enriched TFs, 10 TFs had enrichment in immune system process among their target genes.

CONCLUSIONS

Our genome-wide analysis provides further evidence of ETS and nuclear factor kB involvement in AAA. Additionally, our results provide novel insight for future studies aiming to dissect the pathogenesis of AAA and have uncovered potential therapeutic targets for AAA prevention.

Pharmacological treatment of abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a common degenerative condition with high mortality in older men. Elective surgical or endovascular repair is performed to prevent rupture of large AAAs. In contrast, despite gradual expansion, small AAAs have a low risk of rupture, and there is currently no well-defined treatment strategy for them. Therefore, a pharmacological approach for AAA is expected in the clinical setting. Indeed, several therapeutic effects of pharmacological agents have been reported in experimental models, and some agents have undergone clinical trials. Treatment with statins, angiotensin-converting enzyme-inhibitors, antibiotics, and anti-inflammatory agents appears to inhibit the growth rate of AAA in humans. However, as the sample size and follow-up period were limited in these studies, a large randomized study with long-term follow-up of small AAA should be performed to clarify the effect of these agents. Recently, the regression of AAA using molecular pharmacological approaches was reported in experimental studies. The characteristics of these strategies are the regulation of multiple molecular mediators and the signalling networks associated with AAA formation. On the basis of the results of these investigations, it may be possible to repair the injured aortic wall and obtain the remission of AAA using pharmacological therapy.

Transcriptional regulation of NF-kappaB by ring type decoy oligodeoxynucleotide in an animal model of nephropathy

Inflammation of the tubulointerstitial compartment, leading to fibrosis, is a major factor in the progressive loss of renal function in a wide variety of kidney diseases. In order to develop a therapeutic approach for nephropathy, we examined the simultaneous inhibition of transcription factor nuclear factor-kappaB (NF-kappaB), which is responsible for a wide range of cellular processes, especially inflammation, in a mouse model of unilateral ureteral obstruction. In this study, we employed a ring-type NF-kappaB (R-NF-kappaB) decoy oligodeoxynucleotide (ODN), containing consensus promoter sequences of NF-kappaB. This R-NF-kappaB decoy ODN is more highly resistant to degradation by nucleases than is the current phosphothiolated double stranded NF-kappaB decoy ODN. The inhibitory effect of R-NF-kappaB decoy ODN on nephropathy was confirmed by molecular and histological examinations. In addition, treatment with R-NF-kappaB decoy ODN reduced the activities of inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-1beta. Interestingly, the treatment with R-NF-kappaB decoy ODN also suppressed the gene expression of transforming growth factor-beta1 and fibronectin, resulting in the inhibition of fibrotic changes. These results suggest that the inhibition of NF-kappaB using R-NF-kappaB decoy ODN has potential therapeutic application in the prevention of renal fibrosis.

[Development of cell-selective targeting systems of NFkappaB decoy for inflammation therapy]

NFkappaB regulate several inflammatory related molecules and evoke immune and inflammatory response by several stimuli, therefore inhibition of NFkappaB activation would be a novel therapeutic strategy. To date, there are many conventional drugs including nonsteroldal or steroldal anti-inflammatory drugs or immune suppressors etc. were known to inhibit NFkappaB activation, however, several side effects were also reported. Recently, double stranded oligonucleotide including NFkappaB binding sequence, called NFkappaB decoy, was developed to prevent NFkappaB activation, which is powerful tool in a new class of anti-gene strategy for molecular therapy with low side effect. However, NFkappaB decoy is easily degraded by nuclease and rapidly excreted to urine, therefore it is necessary to develop carrier for NFkappaB decoy therapy. Here, we shall review delivery system for NFkappaB decoy and introduce our cell-selective delivery system for NFkappaB decoy using sugar decorated cationic liposomes.

Inhibition of development of experimental aortic abdominal aneurysm in rat model by atorvastatin through inhibition of macrophage migration

Recently, atherosclerosis has been considered to be the result of inflammation. Interestingly, hydroxymethylglutaryl-coenzyme (HMG-Co) A inhibitors (statins), which are clinically used as lipid-lowering agents, have been reported to have various anti-inflammatory effects. As abdominal aortic aneurysm (AAA) is a common degenerative condition associated with atherosclerosis, this study was designed to investigate the inhibitory effect of a statin, atorvastatin, on aneurysm formation apart from its lipid-lowering effect. We employed an elastase-induced rat AAA model, as statins do not lower cholesterol in rats. Mean aneurysm diameter was significantly smaller in the atorvastatin treatment group as compared to control at 4 weeks after surgery (P<0.05). Interestingly, atorvastatin inhibited the expression of ICAM and MCP-1, followed by the suppression of macrophage recruitment into the aortic wall at 1 week after operation. A significant reduction in MMP-12, but not MMP-2, -3 and -9, expression was also observed by treatment with atorvastatin at 1 week after surgery. In addition, synthesis of collagen and elastin in the vascular wall were significantly increased by atorvastatin. Here, the present study demonstrated a direct effect of atorvastatin to inhibit the progression of aortic aneurysm, independent of its lipid-lowering effect. This study suggests new therapeutic aspects of statins to inhibit the progression of aneurysms.

Increase in nuclease resistance and incorporation of NF-kappaB decoy oligodeoxynucleotides by modification of the 3'-terminus

BACKGROUND

For the development of molecular therapy based on oligodeoxynucleotides (ODN), ODN have to be stable against nucleases and be specific to the target transcription factor. To decrease non-specific binding and degradation from the 3'-terminus of ODN, we designed partially annealed ODN by binding the extremities of two single strands, resulting in a ribbon-shaped ODN, so called ribbon-type decoy ODN (R-ODN).

METHODS

We evaluated the efficiency in the process of enzymatic ligation of R-ODN, the binding activity to nuclear factor-kappaB (NF-kappaB), and the stability against Exonuclease III and nucleases present in serum. The functional activity of R-ODN to inhibit NF-kappaB in vitro was evaluated in human aortic smooth muscle cells (VSMC): TNF-alpha-induced proliferation rate and MMP-9 expression were assessed after R-ODN transfection.

RESULTS AND CONCLUSIONS

Although R-ODN have a phosphodiester backbone, their physical conformation was designed to provide nuclease resistance without interfering with their binding activity. As expected, R-ODN showed more resistance to exonucleases and stability in 100% serum than non-modified decoy ODN (N-ODN). Importantly, the R-ODN construction did not interfere with its binding activity to NF-kappaB, similar to N-ODN. Transfection of R-ODN significantly inhibited the expression of MMP-9 induced by TNF-alpha in VSMC as assessed by real-time polymerase chain reaction (PCR), and R-ODN also inhibited the proliferation of VSMC induced by TNF-alpha (10 ng/ml), similar to phosphorothioate decoy ODN. Overall, the development of ribbon NF-kappaB decoy ODN could provide a useful tool for basic and clinical research.

NF-κB Is a Key Mediator of Cerebral Aneurysm Formation

Background— Subarachnoid hemorrhage caused by the rupture of cerebral aneurysm (CA) remains a life-threatening disease despite recent diagnostic and therapeutic advancements. Recent studies strongly suggest the active participation of macrophage-mediated chronic inflammatory response in the pathogenesis of CA. We examined the role of nuclear factor-κB (NF-κB) in the pathogenesis of CA formation in this study.

Methods and Results— In experimentally induced CAs in rats, NF-κB was activated in cerebral arterial walls in the early stage of aneurysm formation with upregulated expression of downstream genes. NF-κB p50 subunit–deficient mice showed a decreased incidence of CA formation with less macrophage infiltration into the arterial wall. NF-κB decoy oligodeoxynucleotide also prevented CA formation when it was administered at the early stage of aneurysm formation in rats. Macrophage infiltration and expression of downstream genes were dramatically inhibited by NF-κB decoy oligodeoxynucleotide. In human CA walls, NF-κB also was activated, especially in the intima.

Conclusions— Our data indicate that NF-κB plays a crucial role as a key regulator in the initiation of CA development by inducing some inflammatory genes related to macrophage recruitment and activation. NF-κB may represent a therapeutic target of a novel medical treatment for CA.

Regression of abdominal aortic aneurysms by simultaneous inhibition of nuclear factor kappaB and ets in a rabbit model

Because current therapy to treat abdominal aortic aneurysm (AAA), and particularly to manage small AAA, is limited to elective surgical repair, we explored less invasive molecular therapy by simultaneous inhibition of the transcription factors nuclear factor (NF)kappaB and ets using a decoy strategy. Both NFkappaB and ets were shown to be markedly activated in human AAA. In addition, NFkappaB- and ets-positive cells were increased in the aneurysm wall, and a part of the expression of NFkappaB and ets was detected in migrating macrophages. Thus, we used chimeric decoy oligodeoxynucleotides (ODNs) containing consensus sequences of both NFkappaB and ets binding sites to treat AAA. Inhibitory effects of chimeric decoy ODNs on matrix metalloproteinase-1 and -9 expression were confirmed by ex vivo experiments using a human aorta organ culture. To examine the regressive effect in a rabbit already-formed AAA model, transfection by wrapping a delivery sheet containing chimeric decoy ODNs around the aneurysm was performed 1 week after incubation with elastase. Importantly, treatment with chimeric decoy ODNs significantly decreased the size of AAA. Interestingly, significant preservation of elastic fibers was observed with chimeric decoy ODN treatment, accompanied by a reduction of matrix metalloproteinase-2 and -9 and induction of macrophage apoptosis. Regression of AAA was also associated with an increase in elastin and collagen type I and III synthesis in the aneurysm wall. Minimally invasive molecular therapy targeted to the inhibition of NFkappaB and ets is expected to be useful for AAA through the rebalance of matrix synthesis and degradation.

Regulation of MMP-2 Gene Transcription in Dermal Wounds

Matrix metalloproteinase-2 (MMP-2, gelatinase A) plays an essential role in angiogenesis, inflammation, and fibrosis. These processes are critical for wound healing and accordingly elevated levels of MMP-2 expression have been detected after skin injury. Our goal was to investigate the transcriptional activation of the MMP-2 gene in a model of skin injury by using two different MMP-2/LacZ-reporter mice. Upon skin injury MMP-2 expression was upregulated, whereas tissue from normal skin stained negative except for occasional macrophages, sweat glands, and hair follicles. Skin injury also activated MMP-2 proteolytic activity and reporter gene expression. We demonstrate that MMP-2 regulatory sequences -1686/+423 drive appropriate injury-induced MMP-2-promoter activation. Reporter gene expression was predominantly detectable in endothelial cells and in macrophages. Deletion of the 5' responsive element, denoted RE-1, residing at -1241/+423 bp of the regulatory sequence led to abrogated MMP-2 transcription in vivo. The findings define a crucial role for the enhancer element RE-1 in injury-induced MMP-2 transcription of the skin.

Sonoporation is an efficient tool for intracellular fluorescent dextran delivery and one-step double-crossover mutant construction in Fusobacterium nucleatum

Studies of microorganisms are often hindered by a lack of effective genetic tools. One such example is Fusobacterium nucleatum, a gram-negative anaerobe associated with various human infections, including those causing periodontal disease and preterm birth. The first double-crossover allelic-exchange mutant in F. nucleatum was recently constructed using sonoporation, a novel ultrasound-mediated intracellular delivery method, demonstrating potential for bacterial gene transfection. To better unveil its mechanism, the current study examines the factors affecting the outcome of sonoporation. Delivery of Texas Red-conjugated dextran into F. nucleatum by sonoporation was at least twice as efficient as that by electroporation, and sonoporation was nonbactericidal, unlike electroporation. The delivery efficiency was affected by the acoustic pressure amplitude, the duty cycle, and the quantity of microbubbles used to initiate cavitation but not by the pulse repetition frequency of ultrasound application. To examine the involvement of homologous recombination in sonoporation-mediated mutant construction, the highly conserved recA gene, which carried most of the consensus residues, including the P loop, was identified in F. nucleatum, and a double-crossover recA mutant of F. nucleatum 12230, US1610, was constructed by sonoporation. The mutant exhibited increased sensitivity to UV exposure compared with that of the wild type, indicating that the RecA function in F. nucleatum was conserved. Interestingly, US1610 was also sensitive to ultrasound treatment, suggesting the likely involvement of RecA in postsonoporation repair and survival. Since sonoporation has consistently generated one-step double-crossover mutants in F. nucleatum by use of intact suicide plasmids, this technology may be developed into an efficient tool for streamlining mutant construction in bacteria.

Regulation of vascular inflammation and remodeling by ETS factors

The ETS (E26 Transformation-specific Sequence) factors are comprised of a family of transcription factors that share a highly conserved DNA binding domain. Although originally described for their role as protooncogenes in the development of several types of human cancer, they have subsequently been shown to regulate a wide variety of biological processes including cellular growth and differentiation under normal and pathological conditions. As transcription factors, they can either function as activators or repressors of gene expression. Several ETS family members are expressed in cells of vascular origin, including endothelial cells and vascular smooth muscle cells, where they regulate the expression of a number of vascular-specific genes. In the past few years, emerging evidence supports a novel role for selected ETS family members in the regulation of vascular inflammation and remodeling. ETS factor expression can be induced by proinflammatory cytokines, growth factors, and vasoactive peptides. Examples of some of the target genes regulated by ETS factors include adhesion molecules, chemokines, and matrix metalloproteinases. Targeted disruption of selected ETS family members such as Ets-1 in mice is associated with marked reductions in the recruitment of inflammatory cells and vascular remodeling in response to systemic administration of the vasoactive peptide angiotensin II. The purpose of this review is to provide an overview of recent advances that have been made in defining a role for selected members of the ETS transcription factor family in the regulation of vascular-specific gene expression, vascular inflammation, and remodeling.

Hypertension accelerated experimental abdominal aortic aneurysm through upregulation of nuclear factor kappaB and Ets

In this study, we focused on the effect of hypertension on the transcription factors nuclear factor kappaB (NFkappaB) and ets in the mechanisms of abdominal aortic aneurysm (AAA), and we investigated how hypertension affects the progression of AAA. AAA was produced by elastase perfusion in hypertensive rats and normotensive rats. The size of AAA rapidly increased in hypertensive rats as compared with normotensive rats. Western blot analysis demonstrated that the expression of matrix metalloproteinase (MMP)-2, -3 , -9, and -12, as well as intercellular adhesion molecule, was increased in hypertensive AAA rats, accompanied by upregulation of NFkappaB and ets. Moreover, in situ zymography showed that the activity of MMPs was increased in the aorta of a hypertensive AAA model as compared with that in a normotensive AAA model. Interestingly, transfection of chimeric decoy oligodeoxynucleotide (ODN) resulted in significant inhibition of aortic dilatation both in normotensive and hypertensive rats at 4 weeks after transfection. Destruction of elastic fibers was also significantly inhibited by transfection of chimeric decoy ODN in both hypertensive rats and normotensive rats. The expression of MMP-2, -3, -9, and -12, as well as intercellular adhesion molecule, was significantly attenuated by the chimeric decoy ODN, accompanied by inhibition of the migration of macrophages. Also, the effect of chimeric decoy ODN was confirmed in an organ culture. The present study demonstrated that hypertension accelerated the progression of experimental AAA through upregulation of NFkappaB and ets. Inhibition of NFkappaB and ets could be a novel therapeutic strategy to treat AAA in hypertensive patients.