Label-free visualization and quantification of the drug-type-dependent response of tumor spheroids by dynamic optical coherence tomography

We demonstrate label-free dynamic optical coherence tomography (D-OCT)-based visualization and quantitative assessment of patterns of tumor spheroid response to three anti-cancer drugs. The study involved treating human breast adenocarcinoma (MCF-7 cell-line) with paclitaxel (PTX), tamoxifen citrate (TAM), and doxorubicin (DOX) at concentrations of 0 (control), 0.1, 1, and 10 µM for 1, 3, and 6 days. In addition, fluorescence microscopy imaging was performed for reference. The D-OCT imaging was performed using a custom-built OCT device. Two algorithms, namely logarithmic intensity variance (LIV) and late OCT correlation decay speed (OCDS[Formula: see text]) were used to visualize the tissue dynamics. The spheroids treated with 0.1 and 1 µM TAM appeared similar to the control spheroid, whereas those treated with 10 µM TAM had significant structural corruption and decreasing LIV and OCDS[Formula: see text] over treatment time. The spheroids treated with PTX had decreasing volumes and decrease of LIV and OCDS[Formula: see text] signals over time at most PTX concentrations. The spheroids treated with DOX had decreasing and increasing volumes over time at DOX concentrations of 1 and 10 µM, respectively. Meanwhile, the LIV and OCDS[Formula: see text] signals decreased over treatment time at all DOX concentrations. The D-OCT, particularly OCDS[Formula: see text], patterns were consistent with the fluorescence microscopic patterns. The diversity in the structural and D-OCT results among the drug types and among the concentrations are explained by the mechanisms of the drugs. The presented results suggest that D-OCT is useful for evaluating the difference in the tumor spheroid response to different drugs and it can be a useful tool for anti-cancer drug testing.

High-Fat Diet-Induced Diabetic Conditions Exacerbate Cognitive Impairment in a Mouse Model of Alzheimer's Disease Via a Specific Tau Phosphorylation Pattern

BACKGROUND

Epidemiological evidence has demonstrated a clear association between diabetes mellitus and increased risk of Alzheimer's disease (AD). Cerebral accumulation of phosphorylated tau aggregates, a cardinal neuropathological feature of AD, is associated with neurodegeneration and cognitive decline. Clinical and experimental studies indicate that diabetes mellitus affects the development of tau pathology; however, the underlying molecular mechanisms remain unknown.

OBJECTIVE

In the present study, we used a unique diabetic AD mouse model to investigate the changes in tau phosphorylation patterns occurring in the diabetic brain.

DESIGN

Tau-transgenic mice were fed a high-fat diet (n = 24) to model diabetes mellitus. These mice developed prominent obesity, severe insulin resistance, and mild hyperglycemia, which led to early-onset neurodegeneration and behavioral impairment associated with the accumulation of hyperphosphorylated tau aggregates.

RESULTS

Comprehensive phosphoproteomic analysis revealed a unique tau phosphorylation signature in the brains of mice with diabetic AD. Bioinformatic analysis of the phosphoproteomics data revealed putative tau-related kinases and cell signaling pathways involved in the interaction between diabetes mellitus and AD.

CONCLUSION

These findings offer potential novel targets that can be used to develop tau-based therapies and biomarkers for use in AD.

Theoretical model for en face optical coherence tomography imaging and its application to volumetric differential contrast imaging

A new formulation of the lateral imaging process of point-scanning optical coherence tomography (OCT) and a new differential contrast method designed by using this formulation are presented. The formulation is based on a mathematical sample model called the dispersed scatterer model (DSM), in which the sample is represented as a material with a spatially slowly varying refractive index and randomly distributed scatterers embedded in the material. It is shown that the formulation represents a meaningful OCT image and speckle as two independent mathematical quantities. The new differential contrast method is based on complex signal processing of OCT images, and the physical and numerical imaging processes of this method are jointly formulated using the same theoretical strategy as in the case of OCT. The formula shows that the method provides a spatially differential image of the sample structure. This differential imaging method is validated by measuring in vivo and in vitro samples.

Label-free intratissue activity imaging of alveolar organoids with dynamic optical coherence tomography

An organoid is a three-dimensional (3D) in vitro cell culture emulating human organs. We applied 3D dynamic optical coherence tomography (DOCT) to visualize the intratissue and intracellular activities of human induced pluripotent stem cells (hiPSCs)-derived alveolar organoids in normal and fibrosis models. 3D DOCT data were acquired with an 840-nm spectral domain optical coherence tomography with axial and lateral resolutions of 3.8 µm (in tissue) and 4.9 µm, respectively. The DOCT images were obtained by the logarithmic-intensity-variance (LIV) algorithm, which is sensitive to the signal fluctuation magnitude. The LIV images revealed cystic structures surrounded by high-LIV borders and mesh-like structures with low LIV. The former may be alveoli with a highly dynamics epithelium, while the latter may be fibroblasts. The LIV images also demonstrated the abnormal repair of the alveolar epithelium.

Label-free metabolic imaging of non-alcoholic-fatty-liver-disease (NAFLD) liver by volumetric dynamic optical coherence tomography

Label-free metabolic imaging of non-alcoholic fatty liver disease (NAFLD) mouse liver is demonstrated ex vivo by dynamic optical coherence tomography (OCT). The NAFLD mouse is a methionine choline-deficient (MCD)-diet model, and two mice fed the MCD diet for 1 and 2 weeks are involved in addition to a normal-diet mouse. The dynamic OCT is based on repeating raster scan and logarithmic intensity variance (LIV) analysis that enables volumetric metabolic imaging with a standard-speed (50,000 A-lines/s) OCT system. Metabolic domains associated with lipid droplet accumulation and inflammation are clearly visualized three-dimensionally. Particularly, the normal-diet liver exhibits highly metabolic vessel-like structures of peri-vascular hepatic zones. The 1-week MCD-diet liver shows ring-shaped highly metabolic structures formed with lipid droplets. The 2-week MCD-diet liver exhibits fragmented vessel-like structures associated with inflammation. These results imply that volumetric LIV imaging is useful for visualizing and assessing NAFLD abnormalities.

Non-destructive characterization of adult zebrafish models using Jones matrix optical coherence tomography

The zebrafish is a valuable vertebrate animal model in pre-clinical cancer research. A Jones matrix optical coherence tomography (JM-OCT) prototype operating at 1310 nm and an intensity-based spectral-domain OCT setup at 840 nm were utilized to investigate adult wildtype and a tumor-developing zebrafish model. Various anatomical features were characterized based on their inherent scattering and polarization signature. A motorized translation stage in combination with the JM-OCT prototype enabled large field-of-view imaging to investigate adult zebrafish in a non-destructive way. The diseased animals exhibited tumor-related abnormalities in the brain and near the eye region. The scatter intensity, the attenuation coefficients and local polarization parameters such as the birefringence and the degree of polarization uniformity were analyzed to quantify differences in tumor versus control regions. The proof-of-concept study in a limited number of animals revealed a significant decrease in birefringence in tumors found in the brain and near the eye compared to control regions. The presented work showed the potential of OCT and JM-OCT as non-destructive, high-resolution, and real-time imaging modalities for pre-clinical research based on zebrafish.

Visualizing septin and cell dynamics in mammalian brain slices

Correct neuronal migration is crucial for the brain architecture and function. During brain development, excitatory and inhibitory neurons generated in the ventricular zone (VZ) of the dorsal telencephalon and ganglionic medial eminence, respectively, move to their final destinations in tightly regulated spatiotemporal manners. While a variety of morphological methods have been applied to neurobiology, in utero electroporation (IUE) technique is one of the most powerful tools for rapid gain- and loss-of-function studies of brain development. This method enables us to introduce genes of interest into VZ progenitor and stem cells of rodent embryos, and to observe resulting phenotypes such as proliferation, migration, and cell morphology at later stages. In this chapter, we first summarize basic immunohistochemistry methods that are foundations for any advanced methods and showed data on the distribution of Sept6, Sept9, and Sept14 as examples. Then, IUE method is described where functional analyses of Sept14 during brain development are used as examples. We subsequently refer to the in vivo electroporation (IVE)-mediated gene transfer, which is conceptually the same method as IUE, into granule cells of hippocampal dentate gyrus in neonatal mice. Finally, an IUE-based time-lapse imaging method is explained as an advanced technique for the analyses of cortical neuron migration. IUE and IVE methods and the application would contribute greatly to the morphological analyses of septins as well as other molecules to elucidate their neuronal functions and pathophysiological roles in various neurological and psychiatric disorders.

Generation of coherent phonons in a CdTe single crystal using an ultrafast two-phonon laser-excitation process

The detection-energy dependence of a coherent phonon in a (001) CdTe crystal, generated by ultrashort laser pulses with the center energy transparent or opaque to the sample, is investigated using a spectrally resolved pump-probe method. At the excitation in the transparent region, the detection-energy dependence of the phonon amplitude has two peaks at the energy shifted by one times the phonon energy of CdTe from the center energy of the probe pulses. On the other hand, the amplitude in the opaque region shows two peaks at the energy shifted by about two times the phonon energy. This difference occurs even though the observed energies of the coherent phonons in both regions are the same as that of the longitudinal optical phonon of CdTe. The energy shifts in the detection-energy dependence imply that the emission and absorption of one phonon and two phonons in the transparent and opaque regions, respectively, are implicated in coherent phonon generation. In this study, the detection-energy dependence is examined from the viewpoint of the third-order nonlinear susceptibility based on the impulsive stimulated Raman scattering process under nonresonant and resonant conditions.

PGE(2) -EP(2) signalling in endothelium is activated by haemodynamic stress and induces cerebral aneurysm through an amplifying loop via NF-κB

BACKGROUND AND PURPOSE

Cerebral aneurysm is a frequent cerebrovascular event and a major cause of fatal subarachnoid haemorrhage, but there is no medical treatment for this condition. Haemodynamic stress and, recently, chronic inflammation have been proposed as major causes of cerebral aneurysm. Nevertheless, links between haemodynamic stress and chronic inflammation remain ill-defined, and to clarify such links, we evaluated the effects of prostaglandin E(2) (PGE(2) ), a mediator of inflammation, on the formation of cerebral aneurysms.

EXPERIMENTAL APPROACH

Expression of COX and prostaglandin E synthase (PGES) and PGE receptors were examined in human and rodent cerebral aneurysm. The incidence, size and inflammation of cerebral aneurysms were evaluated in rats treated with COX-2 inhibitors and mice lacking each prostaglandin receptor. Effects of shear stress and PGE receptor signalling on expression of pro-inflammatory molecules were studied in primary cultures of human endothelial cells (ECs).

KEY RESULTS

COX-2, microsomal PGES-1 and prostaglandin E receptor 2 (EP(2) ) were induced in ECs in the walls of cerebral aneurysms. Shear stress applied to primary ECs induced COX-2 and EP(2) . Inhibition or loss of COX-2 or EP(2) in vivo attenuated each other's expression, suppressed nuclear factor κB (NF-κB)-mediated chronic inflammation and reduced incidence of cerebral aneurysm. EP(2) stimulation in primary ECs induced NF-κB activation and expression of the chemokine (C-C motif) ligand 2, essential for cerebral aneurysm.

CONCLUSIONS AND IMPLICATIONS

These results suggest that shear stress activated PGE(2) -EP(2) pathway in ECs and amplified chronic inflammation via NF-κB. We propose EP(2) as a therapeutic target in cerebral aneurysm.

Transfection of human HGF plasmid DNA improves limb salvage in Buerger's disease patients with critical limb ischemia

AIM

Hepatocyte growth factor is a potent angiogenic agent. This study investigated the efficacy and safety of intramuscular injection of naked plasmid DNA encoding the human hepatocyte growth factor gene in Japanese patients with Buerger's disease and critical limb ischemia.

METHODS

An open-label clinical study was performed at eight hospitals in Japan from May 2004 to April 2008. Ten patients were enrolled. They had Buerger's disease with ischemic ulcers, were not candidates for revascularization, and were unresponsive to conventional drug therapy. Treatment consisted of 8 injections (total dose: 4 mg) of hepatocyte growth factor plasmid, which were administered into the calf muscles and/or distal thigh muscles of the ischemic limbs under ultrasound guidance. Administration was done twice at an interval of 4 weeks. If there was no improvement after 2 doses, a 3rd dose could be administered. The response to treatment was evaluated from the reduction of ischemic ulcer size.

RESULTS

The size of ischemic ulcers showed a decrease in 6/9 (66.7%) patients and the ulcers healed completely in 5/9 (55.6%) patients after gene therapy. Major amputation was not required. There were no deaths and no major safety concerns.

CONCLUSION

Hepatocyte growth factor gene therapy is safe and effective for critical limb ischemia in patients with Buerger's disease.

Ets-1 promotes the progression of cerebral aneurysm by inducing the expression of MCP-1 in vascular smooth muscle cells

Cerebral aneurysm (CA) rupture is one of the leading causes of stroke death. Recent experimental studies suggest that the pathophysiology of CA is closely associated with inflammation. A transcription factor, Ets-1, has been shown to regulate vascular inflammation and remodeling in a physiological and pathological condition. The expression and role of Ets-1 in CA development has been investigated in this study. Ets-1 was expressed and activated mainly in vascular smooth muscle cells (VSMCs) in both experimentally induced rat CAs and human CA walls by immunohistochemistry, western blotting and enzyme-linked mobility shift assay. The downstream target of Ets-1 in CA development was identified by chromatin immunoprecipitation (CHIP) analysis. CHIP analysis revealed that Ets-1 transactivated monocyte chemoattractant protein-1 (MCP-1) expression in CA walls. Treatment with ets decoy oligodeoxynucleotides resulted in the prevention of CA enlargement, upregulation of MCP-1 expression and increase in macrophage accumulation in CA walls. In conclusion, Ets-1 mediates MCP-1 expression in VSMCs in CA walls, thus promoting the progression of CAs. Inhibition of DNA-binding activity of Ets-1 may lead to the prevention of human CA enlargement and rupture. Results of this study will provide us a clue to a novel therapeutic strategy for CAs.

Effect on vein graft intimal hyperplasia of nuclear factor-kB decoy transfection using the second generation of HVJ vector

AIM

Vein graft stenosis due to intimal hyperplasia (IH) is the main cause of graft failure. We examined possibilities of nuclear factor-kB (NF-kB) expression in vein grafts, and inhibitive effects of NF-kB decoy on the gene expression and subsequent vein graft IH.

METHODS

Fifteen mongrel dogs underwent femoral artery replacement with autogenous vein grafts. Group I: grafts were retrieved at a predetermined time and subjected to NF-kB binding activity assay; Groups II and III: grafts were transfected with scrambled (II-a, III-a) or NF-kB (II-b, III-b) decoy using hemagglutinating virus of Japan envelope before implantation. Grafts were retrieved 7 days after implantation for evaluation of intercellular adhesion molecule-1 (ICAM-1) mRNA expression (Group II) and 4 weeks after implantation for comparison of IH by morphometric analysis (Group III).

RESULTS

NF-kB binding activity was increased in a time-dependent manner, with a peak 2 days after implantation. The ratio between ICAM-1 and glyceraldehyde-3-phosphate dehydrogenase mRNA expression in II-b was significantly lower than that in II-a (0.347 +/- 0.07 versus 0.612+/-0.08; P = 0.047). The ratio of intimal cross-section area to luminal cross-section area of III-b was significantly lower than that of the III-a (0.096+/-0.03 versus 0.461+/-0.11; P = 0.048).

CONCLUSION

NF-kB binding activity in vein grafts increases after implantation, and transfection of NF-kB decoy before implantation may reduce IH through the inhibition of ICAM-1 expression.

Essential roles of ERK-mediated phosphorylation of vinexin in cell spreading, migration and anchorage-independent growth

Vinexin is an adaptor protein supposed to play pivotal roles in various cellular events such as cell adhesion, cytoskeletal organization, signaling and gene expression. Despite the possible importance, physiological functions and regulatory mechanisms of vinexin are largely unknown. In addition, although vinexin was reported to be phosphorylated by extracellular signal-regulated kinase (ERK), physiological significance of the phosphorylation remains to be elucidated. Here we carried out characterization of endogenous vinexin and found that it was enriched at the leading edge of migrating cells and focal adhesions of spread cells. In the analyses using ERK-phosphorylated vinexin-specific antibody, the phosphorylation signal was also detected at the leading edges of migrating cells and at cell periphery of spreading cells, whereas only faint signal was observed at focal adhesions of well-spread cells. We then established LNCaP cell lines stably expressing GFP-fused vinexinbeta or two mutants at Ser189 that mimic the ERK-phosphorylated or -unphosphorylated vinexin beta. Based on the analyses using the lines, the phosphorylation was likely to inhibit the cell spreading and migration. On the other hand, anchorage-independent cell growth was inhibited by unphosphorylated vinexinbeta. Taken together, ERK-mediated phosphorylation of vinexinbeta is strongly suggested to occur in a spatio-temporally regulated manner and play important roles in cell spreading, migration and anchorage-independent growth.

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

Abdominal aortic aneurysm (AAA) is one of the major vascular diseases caused by atherosclerosis. Because treatment for AAA mainly consists of surgery to prevent deaths from AAA rupture and there is a conspicuous absence of alternative therapeutic strategies, the development of minimally invasive treatment is needed. To develop a novel therapeutic approach, we examined the simultaneous inhibition of the transcription factors NFkappaB and ets, which regulate inflammation and matrix degradation, in a rabbit AAA model. In this study, we employed chimeric decoy oligodeoxynucleotides (ODN), containing the consensus sequences of both the NFkappaB- and ets-binding sites, to inhibit both the transcription factors simultaneously. Using a delivery sheet, we examined the inhibitory effect of chimeric decoy ODN on aortic dilatation. Ultrasound and angiographic analysis demonstrated that treatment with chimeric decoy ODN significantly prevented the progression of elastase-induced aortic dilatation. The inhibitory effect of chimeric decoy ODN on aortic dilatation was also confirmed by histological studies. Treatment with chimeric decoy ODN reduced the activities of matrix metalloproteinase (MMP)-2 and MMP-9 and markedly inhibited the proteolysis of elastin as compared to scrambled decoy ODN. Interestingly, treatment with chimeric decoy ODN also suppressed VCAM-1 and MCP-1 gene expression, leading to inhibition of macrophage infiltration in the adventitia and media. The present study in a rabbit model provides a novel strategy to treat AAA by the simultaneous inhibition of both NFkappaB and ets using chimeric decoy ODN. Further modification of chimeric decoy ODN would be useful to treat AAA as a decoy-based therapy.

Prevention of onset of Parkinson's disease by in vivo gene transfer of human hepatocyte growth factor in rodent model: a model of gene therapy for Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra (SNi). As neurotrophic factors support the survival and enhance the function of dopaminergic neurons, gene therapy using neurotrophic factors has become the center of interest. Thus, we focused on hepatocyte growth factor (HGF) as a neurotrophic and angiogenic growth factor. At 7 days before injection of 6-hydroxydopamine into the SNi, stereotaxic transfection of human HGF or lacZ plasmid was performed into the unilateral striatum of rats. Expression of human HGF in the injected sites could be detected in rats transfected with HGF plasmid DNA, using immunohistochemical staining. Consistently, human immunoreactive HGF protein could be detected at least up to 12 days after transfection. Interestingly, PD rats transfected with lacZ demonstrated amphetamine-induced rotational asymmetry. However, transfection of HGF plasmid DNA resulted in significant inhibition of abnormal rotation up to 24 weeks in a dose-dependent manner. Over 90% of dopaminergic neurons were lost in PD rats transfected with lacZ, whereas over 70% survived in rats transfected with HGF, as assessed by immunohistochemical staining. Overall, the present study demonstrated that overexpression of HGF prevented neuronal death in a PD rat model, providing a potential novel therapy for PD.

Angiogenic and antifibrotic actions of hepatocyte growth factor improve cardiac dysfunction in porcine ischemic cardiomyopathy

Impairment of cardiac function in ischemic cardiomyopathy has been postulated to be due to the decrease in blood flow and increase in collagen synthesis. Therefore, an approach to alter them directly by means of a growth factor may open up a new therapeutic concept in ischemic cardiomyopathy. From this viewpoint, hepatocyte growth factor (HGF) is a unique growth factor with angiogenic and antifibrotic effects. Thus, we examined the feasibility of gene therapy using HGF plasmid DNA for ischemic cardiomyopathy. Human HGF plasmid DNA at a dose of 0.4 or 4 mg was injected into ischemic myocardium of pigs induced by ameroid constrictor with the NOGA system. At 1 month after injection, the ischemic area was significantly reduced in the HGF group, accompanied by a significant increase in capillary density and regional myocardial perfusion in the ischemic area (P<0.01). In contrast, a significant decrease in fibrotic area was observed in the HGF group, associated with a significant decrease in collagen I, III and TGF-beta synthesis as compared to the control group (P<0.01). Consistently, cardiac function was significantly improved in the 4 mg HGF group as compared to the control group (P<0.05). Overall, the present in vivo experiments demonstrated that intramyocardial injection of human HGF plasmid DNA in ischemic cardiomyopathy resulted in a significant improvement in cardiac function through an increase in blood flow and decrease in fibrosis. These favorable outcomes suggest potential utility to treat patients with ischemic heart disease using HGF gene transfer. Currently, a phase I study using human HGF plasmid DNA is ongoing to test the validity of this concept.

Acceleration of wound healing by combined gene transfer of hepatocyte growth factor and prostacyclin synthase with Shima Jet

Although skin diseases are one of the target diseases for gene therapy, there has been no practical gene transfer method. First, we examined gene transfer efficiency of the spring-powered jet injector, Shima Jet, which was originally developed as a non-needle jet injector of insulin. Local gene expression was about 100 times higher when the luciferase plasmid was transferred by the Shima Jet than by a needle. Gene transfer of beta-galactosidase revealed gene expression in the epidermis. Based on these results, we then examined the potential of gene therapy using the Shima Jet for wound healing. An increase of cellular proliferation of the epidermis and the number of microvessels in the granulation tissue was observed after hepatocyte growth factor (HGF) gene transfer. An increase in blood flow around the wound was observed after prostacyclin synthase (PGIS) gene transfer. Moreover, promotion on wound healing was observed in HGF gene transferred group, and further promotion was observed in combined gene transferred group as assessed by measuring wound area. These results indicate that co-transfer of HGF and PGIS genes by the Shima Jet could be an effective strategy to wound healing.

NFkappaB decoy oligodeoxynucleotides ameliorates osteoporosis through inhibition of activation and differentiation of osteoclasts

The transcription factor, nuclear factor-kappa B (NFkappaB), is believed to play a pivotal role in osteoclast formation. In this study, we focused on NFkappaB decoy oligodeoxynucleotides (ODN) as a new therapeutic strategy to attenuate osteoporosis. Tartrate-resistant acid phosphatase (TRAP)-positive multinuclear osteoclasts formed in mononuclear cells including osteoclast precursors from neonatal rabbit bone marrow were increased in the presence of 1,25-dihydroxyvitamin D3, whereas transfection of NFkappaB decoy ODN decreased the number of TRAP-positive cells and attenuated RANKL and M-CSF-induced osteoclast formation. NFkappaB decoy ODN also inhibited the activity of osteoclasts, as assessed by pit formation. In rat ovariectomized model of estrogen deficiency, continuous administration of NFkappaB decoy ODN attenuated the increase of TRAP activity, accompanied by a significant increase in calcium concentration in tibia and femur and decrease in urinary deoxypyridinoline. In additional osteoporosis model using vitamin C-deficient rat, inhibition of NFkappaB by decoy ODN dramatically improved the bone length, weight, density as assessed by dual-energy X-ray absorptiometry. Overall, inhibition of NFkappaB by decoy strategy prevented osteoporosis through the inhibition of bone resorption. Targeting of NFkappaB might be potential therapy in various bone metabolic diseases.

Inhibition of ets, an essential transcription factor for angiogenesis, to prevent the development of abdominal aortic aneurysm in a rat model

The pathophysiology of abdominal aortic aneurysms (AAA) is considered to be complicated. As matrix degradation contributes to the progression of AAA, the destruction and degradation of elastin fibers caused by an increase in matrix metalloproteinases (MMPs) plays a pivotal role in the development of AAA. Although ets, an essential transcription factor for angiogenesis, regulates MMPs, the role of ets in the development of AAA has not yet been clarified. Thus, we evaluated the role of ets in a rat AAA model using a decoy strategy. Transfection of ODN into AAA was performed by transient aortic perfusion of elastase and by wrapping the AAA in a delivery sheet containing decoy ODN. The inhibitory effect of ets decoy ODN on ets binding activity was confirmed by gel mobility shift assay. MMPs expression was decreased in the aorta transfected with ets decoy ODN as compared to scrambled decoy ODN. Also, ultrasound study demonstrated that elastase-induced aneurismal dilation was significantly suppressed by transfection of ets decoy ODN at 4 weeks after treatment as compared to scrambled decoy ODN. Moreover, the destruction of elastin fibers was inhibited in the aorta transfected with ets decoy ODN, accompanied by a reduction of MMPs expression. An inhibitory effect of decoy ODN on MMP expression was confirmed by ex vivo experiments showing that transfection of decoy ODN into an organ culture of human aorta resulted in significant inhibition of the secretion of both MMP-1 and MMP-9. Here, we demonstrated that ets may play a pivotal role in the progression of AAA through the activation of MMPs in a rat model. Ets might be a potential target to develop pharmacotherapy/gene therapy to treat AAA through the inhibition of MMPs.

Liver-directed gene therapy of diabetic rats using an HVJ-E vector containing EBV plasmids expressing insulin and GLUT 2 transporter

Insulin gene therapy in clinical medicine is currently hampered by the inability to regulate insulin secretion in a physiological manner, the inefficiency with which the gene is delivered, and the short duration of gene expression. To address these issues, we injected the liver of streptozotocin-induced diabetic rats with hemagglutinating virus of Japan-envelope (HVJ-E) vectors containing Epstein-Barr virus (EBV) plasmids encoding the genes for insulin and the GLUT 2 transporter. Efficient delivery of the genes was achieved with the HVJ-E vector, and the use of the EBV replicon vector led to prolonged hepatic gene expression. Blood glucose levels were normalized for at least 3 weeks as a result of the gene therapy. Cotransfection of GLUT 2 with insulin permitted the diabetic rats to regulate their blood glucose levels upon exogenous glucose loading in a physiologically appropriate manner and improved postprandial glucose levels. Moreover, cotransfection with insulin and GLUT 2 genes led to in vitro glucose-stimulated insulin secretion that involved the closure of K(ATP) channels. The present study represents a new way to efficiently deliver insulin gene in vivo that is regulated by ambient glucose level with prolonged gene expression. This may provide a basis to overcome limitations of insulin gene therapy in humans.

Effect of nifedipine on endothelial function in normotensive smokers: potential contribution of increase in circulating hepatocyte growth factor

Calcium antagonists are reported to have protective effects on the endothelium in vitro and in vivo. Especially, nifedipine, among many calcium antagonists, was shown to improve endothelial dysfunction in patients with hypertension. However, no report has determined whether the improvement of endothelial dysfunction by nifedipine is due to direct effects or indirect effects such as its hypotensive effect. Thus, in this study, we evaluated the direct effects of nifedipine on smoking-induced endothelial dysfunction, since cigarette smoking itself is a major factor in damage of endothelial cells, as well as hypertension. We examined whether nifedipine improves endothelial function in 10 normotensive smokers without any risk factors for atherosclerosis. The subjects were treated with 20 mg nifedipine monotherapy (n = 10) or placebo (n = 10) for 4 weeks. Nifedipine did not affect blood pressure and heart rate of normotensive smokers. We measured forearm blood flow (FBF) by strain-gauge plethysmography after 2 and 4 weeks of treatment. Changes in vasodilator response to reactive hyperaemia were significantly improved in nifedipine-treated subjects (P < 0.05), while there was no significant change in FBP response in control subjects. Response to nitroglycerin was not changed in either group. Moreover, to evaluate the mechanisms of the direct effects of nifedipine on the endothelium, we focused on hepatocyte growth factor (HGF), which is a novel angiogenic growth factor with an antiapoptotic action on endothelial cells. Interestingly, serum HGF concentration in smokers treated with nifedipine was significantly elevated both at 2 and 4 weeks (P < 0.05). Overall, these results demonstrated direct effects of nifedipine in the improvement of endothelial dysfunction in normotensive smokers. The increase in serum HGF concentration by nifedipine might contribute to the improvement of endothelial dysfunction.

Development of efficient plasmid DNA transfer into adult rat central nervous system using microbubble-enhanced ultrasound

Although gene therapy might become a promising approach for central nervous system diseases, the safety issue is a serious consideration in human gene therapy. To overcome this problem, we developed an efficient gene transfer method into the adult rat brain based on plasmid DNA using a microbubble-enhanced ultrasound method, since microbubble-enhanced ultrasound has shown promise for transfecting genes into other tissues such as blood vessels. Using the microbubble-enhanced ultrasound method, luciferase expression was increased approximately 10-fold as compared to injection of naked plasmid DNA alone. Interestingly, the site of gene expression was limited to the site of insonation with intracisternal injection, in contrast to previous studies using viruses. Expression of the reporter gene, Venus, was readily detected in the central nervous system. The transfected cells were mainly detected in meningeal cells with intracisternal injection, and in glial cells with intrastriatal injection. There was no obvious evidence of tissue damage by microbubble-enhanced ultrasound. Overall, the present study demonstrated the feasibility of efficient plasmid DNA transfer into the central nervous system, providing a new option for treating various diseases such as tumors.

Antisense oligonucleotides as a powerful molecular strategy for gene therapy in cardiovascular diseases

Antisense oligonucleotides (ODN) technology is one of the most promising therapeutic strategies to prevent the progress of diseases through inhibiting the specific gene expression. They are well established to serve as molecular tools for several biologic applications, from the study of single gene function up to complex target validations. From the theoretical simple action, sequence-specific inhibition of mRNA functions after complex formation and presumably enzymatic degradation of the target mRNA, they obviously carry a high therapeutic potential to treat human diseases. In addition to the potential for the treatment, antisense ODN may be applicable for investigations of the mechanism and stereochemistry of biochemical reactions, mapping of nucleic acid protein interactions, and diagnostic applications. However, the design of antisense ODN, is very difficult because many factors affecting their activity and stability must be considered. Especially, the modifications of ODN are very critical and many researchers are trying to establish ODN which have resistance to nucleolytic degradation, high affinity to complementary nucleic acid, high selectivity in binding with complementary nucleic acid, the ability to activate ribonuclease H that selectively degrades the RNA strand of ODN-RNA complex, cell permeability, and favorable pharmacokinetic and pharmacodynamic attributes. In this review we would like to introduce some modifications of ODN design and examples of our applications of antisense ODN in cardiovascular disease in animal models.

Transcription factor decoy for AP-1 reduces mesangial cell proliferation and extracellular matrix production in vitro and in vivo

Diabetic nephropathy is characterized by an expansion of glomerular mesangium, caused by mesangial cell proliferation and excessive accumulation of extracellular matrix (ECM) proteins, which eventually leads to glomerulosclerosis and renal failure. Activator protein-1 (AP-1), a transcription factor, is implicated in the transcriptional regulation of a wide range of genes participating in cell proliferation and ECM production. This investigation was undertaken to test the hypothesis that AP-1 plays an important role in ECM gene expression, and to develop a molecular therapeutic strategy based on decoy oligodeoxynucleotides (ODN). In this report, we show that transfection with AP-1 decoy ODN strongly inhibits high glucose- and angiotensin II-induced cell proliferation and expression of ECM genes in cultured mesangial cells in vitro. Administration of AP-1 decoy ODN into streptozotocin-induced diabetic rat kidney in vivo using the hemagglutinating virus of Japan (HVJ)-liposome method virtually abolished TGF-beta1 and plasminogen activator inhibitor-1 expression. Our results collectively indicate that AP-1 activation is crucial for mesangial cell proliferation and ECM production in response to high glucose and angiotensin II. Moreover, use of stable AP-1 decoy ODN combined with the highly effective HVJ-liposome method provides a novel potential molecular therapeutic strategy for the prevention of diabetic nephropathy.

Inhibition of neointimal hyperplasia after balloon injury by cis-element 'decoy' of early growth response gene-1 in hypercholesterolemic rabbits

Early growth response factor-1 (Egr-1) is a transcription factor that is rapidly activated after vascular injury and thus might contribute to vascular proliferation and inflammation. We hypothesized that Egr-1 might therefore be a therapeutic target against restenosis. Hypercholesterolemic rabbits were intraluminally administered synthetic DNA as a 'decoy' against Egr-1 immediately after carotid artery balloon injury. Efficient transfection was confirmed by the delivery of a fluorescence-labeled decoy. Gel mobility-shift assay showed increased Egr-1 activity after balloon injury and its prevention by Egr-1 decoy transfection in vivo. Egr-1 decoy transfection attenuated early inflammation and proliferation and later neointimal hyperplasia. In addition, Egr-1 decoy transfection reduced gene expression and protein production of Egr-1-dependent genes such as platelet-derived growth factor-B, transforming growth factor-beta1, and monocyte chemoattractant protein-1. The Egr-1 pathway has an essential role in the pathogenesis of neointimal hyperplasia after balloon injury in hypercholesterolemic rabbits. This decoy strategy is a potential practical form of therapy for human restenosis.

Transfection of NFkappaB-decoy oligodeoxynucleotides using efficient ultrasound-mediated gene transfer into donor kidneys prolonged survival of rat renal allografts

Nuclear factor kappaB (NFkappaB) plays a pivotal role in the coordinated transactivation of a series of genes of cytokines and adhesion molecules that are highly involved in the onset of acute rejection in organ transplantation. We previously developed decoy cis-elements oligo deoxyribonucleic acid against NFkappaB (NFkappaB-decoy) that effectively inhibited the activation of major inflammatory mediators in vitro and in vivo. Accordingly, we hypothesized that transfection of NFkappaB-decoy into the donor kidney would prevent acute rejection and prolong graft survival, and thus provide effective therapy for renal acute rejection. To transfect NFkappaB-decoy, we employed a novel approach using ultrasound exposure with an echocardiographic contrast agent, Optison, and clearly demonstrated successful transfection of NFkappaB-decoy into renal tissue. The therapeutic effect of NFkappaB-decoy on renal allografts was then evaluated in a rat renal allograft model (Wistar-Lewis). In the control group, graft function significantly deteriorated with marked destruction of renal tissue, accompanied by increased production of major inflammatory mediators, and all animals died of renal failure by 9 days. In contrast, graft function (serum creatinine on day 2, NFkappaB-treated: 0.97+/-0.16 versus control: 1.84+/-0.23 mg/dl, P<0.01) and histological structure were well preserved with significantly decreased expression of NFkappaB-regulated cytokines and adhesion molecules, including IL-1, iNOS, MCP-1, TNF-alpha, and ICAM-1, in allografts transfected with NFkappaB-decoy. As a result, animal survival was significantly prolonged in this group as compared to controls (14.2+/-5.2 versus 7.1+/-1.2 days, P<0.01). Thus, we established a novel ultrasound-Optison-mediated gene transfection approach and demonstrated the significant prolongation of graft survival by the successful transfection of NFkappaB-decoy into the donor kidney in a rat renal allograft model.

Inhibition of NFkappaB activation using cis-element 'decoy' of NFkappaB binding site reduces neointimal formation in porcine balloon-injured coronary artery model

Application of DNA technology to regulate the transcription of disease-related genes has important therapeutic potential. The transcription factor NFkappaB plays a pivotal role in the transactivation of inflammatory and adhesion molecule genes, leading to vascular lesion formation. Double-stranded DNA with high affinity for NFkappaB may be introduced as 'decoy' cis elements to bind NFkappaB and block the activation of genes mediating inflammation, resulting in effective drugs for treating intimal hyperplasia. In this study, we tested the feasibility of NFkappaB decoy therapy to treat neointimal formation in a porcine coronary artery balloon injury model as a pre-clinical study. An angioplasty catheter was introduced into the left anterior descending coronary artery of the pig to cause vascular injury. First, we tested the feasibility of transfection of FITC-labeled NFkappaB decoy ODN using a hydrogel balloon catheter. Fluorescence due to NFkappaB decoy ODN could be detected throughout the medial layer. Therefore, we transfected NFkappaB decoy ODN into the balloon-injured LAD using a hydrogel catheter. Histological evaluation demonstrated that the neointimal area in the balloon-injured artery was significantly reduced by NFkappaB decoy ODN as compared to scrambled decoy ODN at 1 week after single transfection, accompanied by a significant reduction in PCNA-positive stained cells (P < 0.01). Interestingly, the reduction of ICAM-positive staining was observed, accompanied by the inhibition of migration of macrophages. Of importance, intravascular ultrasound (IVUS) confirmed that neointimal area in the balloon-injured artery was significantly reduced by NFkappaB decoy ODN at 4 weeks after transfection (P < 0.01). Interestingly, the inhibition of neointimal area was only limited to the lesion transfected with NFkappaB decoy ODN, while other lesions without NFkappaB decoy ODN demonstrated a marked increase in neointimal formation. Here, we report the successful in vivo transfer of NFkappaB decoy ODN using a hydrogel catheter to inhibit vascular lesion formation in balloon-injured porcine coronary artery.

HGF/NK4 inhibited VEGF-induced angiogenesis in in vitro cultured endothelial cells and in vivo rabbit model

AIMS/HYPOTHESIS

As vascular endothelial growth factor (VEGF) plays a pivotal role in the development of diabetic retinopathy, inhibition of angiogenesis induced by VEGF is crucial to treat diabetic retinopathy. HGF (hepatocyte growth factor)/NK4, containing the N-terminal hairpin domain and the four subsequent kringle domains of HGF, is considered as a specific antagonist for HGF. Our aim was to explore the inhibitory effects of HGF/NK4 on angiogenesis induced by VEGF.

METHODS

To analyze the in vivo angiogenesis, we used rabbit corneal micropocket assay. Proliferation and migration of human endothelial cells, expression of ets-1, an essential transcription factor for angiogenesis, and the phosphorylation of extracellular signal-regulated kinase (ERK) was examined with or without HGF/NK4.

RESULTS

Using corneal micropocket assay, in vivo administration of HGF/NK4 inhibited angiogenesis induced by VEGF. HGF/NK4 inhibited proliferation and migration of human endothelial cells induced by VEGF in a dose-dependent manner. Interestingly, VEGF-mediated phosphorylation of ERK was significantly attenuated by HGF/NK4. Of importance, HGF/NK4 attenuated the increase in ets-1 protein stimulated by VEGF. Nevertheless, HGF/NK4 did not affect phosphorylation of VEGF receptor-2 [kinase domain region (KDR)/foetal liver kinase (Flk)-1]. Although tyrosine phosphatase inhibitor (Na(3)VO(4)), or okadaic acid, serine-threonin kinase inhibitor, did not prevent the inhibition of ERK phosphorylation by HGF/NK4, co-incubation of HGF/NK4 with VEGF significantly diminished mitogen-activated protein (MAP) ERK kinase (MEK) phosphorylation (p<0.01).

CONCLUSIONS/INTERPRETATION

Overall, HGF/NK4 inhibited angiogenesis induced by VEGF through inhibition of phosphorylation of ERK and ets-1 expression in in vitro cultured endothelial cells and in vivo rabbit model.

Novel E2F decoy oligodeoxynucleotides inhibit in vitro vascular smooth muscle cell proliferation and in vivo neointimal hyperplasia

The transcription factor, E2F, plays a critical role in the trans-activation of several genes involved in cell cycle regulation. Previous studies showed that the transfection of cis element double-stranded decoy oligodeoxynucleotides (ODNs) corresponding to E2F binding sites inhibited the proliferation of vascular smooth muscle cells (VSMCs) and neointimal hyperplasia in injured vessels. We have developed a novel E2F decoy ODN with a circular dumbbell structure (CD-E2F) and compared its effects with those of the conventional phosphorothioated E2F decoy (PS-E2F) ODN. CD-E2F ODN was more stable than PS-E2F ODN, largely preserving its structural integrity after incubation in the presence of nucleases and sera. Moreover, CD-E2F ODN inhibited high glucose- and serum-induced transcriptional expression of cell cycle regulatory genes more strongly than PS-E2F ODN. Transfection of CD-E2F ODN resulted in more effective inhibition of VSMC proliferation in vitro and neointimal formation in vivo, compared with PS-E2F ODN. An approximately 40-50% lower dose of CD-E2F ODN than PS-E2F ODN was sufficient to attain similar effects. In conclusion, our results indicate that CD-E2F ODN may be a valuable tool in gene therapy protocols for inhibiting VSMC proliferation and studying transcriptional regulation.

Apolipoprotein E-deficient mice created by systemic administration of antisense oligodeoxynucleotides: a new model for lipoprotein metabolism studies

Atherosclerotic cardiovascular disease results from complex interactions among multiple genetic and environmental factors. Thus, it is important to elucidate the influence of each factor on cholesterol metabolism. For this purpose, transgenic/gene-targeting technology is a powerful tool for studying gene functions. However, this technology has several disadvantages such as being time consuming and expensive. Accordingly, we established new animal models using in vivo gene transfer technology. In this study, we examined the feasibility of the creation of a new animal model for the study of atherosclerosis. We hypothesized that apolipoprotein (apo) E-deficient mice can be created by systemic administration of antisense apo E oligodeoxynucleotides (ODN) coupled to the HVJ-liposome complex. Initially, we examined the localization and cellular fate of FITC-labeled antisense ODN administered intravenously. FITC-labeled ODN transfection by the HVJ-liposome method resulted in fluorescence in the liver, spleen and kidney, but not in other organs such as brain. Moreover, fluorescence with the HVJ-liposome method was sustained for up to 2 weeks after transfection, which resulted in a striking difference from transfection of ODN alone or ODN in liposomes without HVJ, which showed rapid disappearance of fluorescence (within 1 day). Given these unique characteristics of the HVJ-liposome method, we next examined transfection of antisense apo E ODN by intravenous administration. Transfection of antisense apo E ODN resulted in a marked reduction of apo E mRNA levels in the liver, but no change in apo B and beta-actin mRNA levels. In mice fed a normal diet, a transient increase in cholesterol and triglyceride levels was observed in the antisense apo E-treated group, but they returned to normal levels by 6 days after transfection. Similar findings were also found in mice fed a high cholesterol diet. Neither scrambled nor mismatched ODN resulted in any increase in cholesterol. To make chronic hypercholesterolemic mice, we therefore performed repeated injections of apo E antisense ODN. Whenever antisense apo E ODN were injected, mice showed a transient increase in cholesterol and triglyceride. Cumulative administration of antisense apo E ODN resulted in a sustained increase in cholesterol for up to 3 weeks after the last transfection. Finally, mice treated with repeated injections of antisense apo E every week developed sustained hypercholesterolemia and hypertriglyceridemia until withdrawal of injections. Apolipoprotein-deficient mice created by intravenous administration of antisense ODN are a promising new animal model to help understand the role of apolipoprotein in vivo and develop a new drug therapy targeting apolipoprotein.

Impaired endothelial dysfunction in diabetes mellitus rats was restored by oral administration of prostaglandin I2 analogue

We have previously reported that a decrease in hepatocyte growth factor (HGF), which has many protective functions against endothelial damage by high d-glucose, might be a trigger of endothelial injury. However, the regulation of vascular HGF in diabetes mellitus (DM) has not been clarified in vivo, although vascular disease is frequently observed in DM patients. In addition, our previous report revealed that a prostaglandin I(2) (PGI(2)) analogue prevented endothelial cell death through the induction of vascular HGF production in cultured human epithelial cells. Thus, in this study, we examined the effects of a PGI(2) analogue in the regulation of the local HGF system using DM rats. A PGI(2) analogue (beraprost sodium; 300 and 600 micro g/kg per day) or vehicle was administered to 16-week-old DM rats induced by administration of streptozotocin for 28 days. Endothelial function was evaluated by the vasodilator response to acetylcholine, and the expression of vascular HGF mRNA was measured by Northern blotting. Of importance, expression of HGF mRNA was significantly decreased in the blood vessels of DM rats as compared with non-DM (P<0.01). In addition, the in vitro vasodilator response of the abdominal aorta to acetylcholine was markedly impaired in DM rats. Importantly, the vasodilator response was restored by PGI(2) treatment in a dose-dependent manner (P<0.01), whereas N(omega)-nitro-l-arginine methyl ester inhibited the restoration of endothelial function. Of particular interest, vascular HGF mRNA and protein were significantly increased in the blood vessels of DM rats treated with PGI(2) as compared with vehicle. Similarly, an increase in HGF protein was also confirmed by immunohistochemical analysis. In addition, the specific HGF receptor, c-met, was also increased by PGI(2) treatment. Overall, this study demonstrated that treatment with a PGI(2) analogue restored endothelial dysfunction in DM rats, accompanied by the induction of vascular HGF and c-met expression. Increased local vascular HGF production by a PGI(2) analogue may prevent endothelial injury, potentially resulting in the improvement of endothelial dysfunction.

Prevention and regression of atopic dermatitis by ointment containing NF-kB decoy oligodeoxynucleotides in NC/Nga atopic mouse model

Atopic dermatitis, a chronic inflammatory skin disease characterized by relapsing eczema and intense prurigo, requires effective and safe pharmacological therapy. In this study, we examined the efficacy of ointment containing NF-kB decoy oligodeoxynucleotides (ODN) on atopic dermatitis lesions in NC/Nga mice, which are characterized by the spontaneous onset of atopic dermatitis in conventional conditions. Topical administration of NF-kB decoy ODN twice a month resulted in a significant reduction in clinical skin condition score and marked improvement of histological findings. Reduction of the atopic skin condition by NF-kB decoy ODN was accompanied by a significant decrease in migration of mast cells into the dermis and an increase in apoptotic cells. Here, we demonstrated the successful treatment of atopic dermatitis with ointment containing NF-kB decoy ODN in a mouse model, promising new therapy for atopic dermatitis.

Molecular strategy using cis-element 'decoy' of E2F binding site inhibits neointimal formation in porcine balloon-injured coronary artery model

Transcription factor E2F plays a pivotal role in the transactivation of cell cycle regulatory genes, leading to vascular lesion formation. Double-stranded DNA with high affinity for E2F as 'decoy' cis elements may block the activation of genes mediating the cell cycle, resulting in an effective therapeutic agent for treating intimal hyperplasia. In this study, we tested the feasibility of E2F decoy therapy to treat neointimal formation in a porcine coronary artery balloon injury model. An angioplasty catheter was inserted in the left anterior descending coronary artery of pigs to cause vascular injury. Initially, we tested the feasibility of transfection of FITC-labeled E2F decoy ODN using a hydrogel balloon catheter. Fluorescence due to E2F decoy ODN could be detected throughout the medial layer. Therefore, we transfected E2F decoy ODN into the balloon-injured artery using hydrogel catheter. Of importance, intravascular ultrasound (IVUS) and histological evaluation demonstrated that plaque area in the balloon-injured artery was significantly reduced by E2F decoy ODN compared with mismatched decoy ODN at 1 month after a single transfection (P < 0.01). In contrast, luminal and total vessel areas were significantly increased in vessels treated with E2F decoy ODN as compared with mismatched decoy. Endothelial function after angioplasty was not affected by E2F decoy transfection. Finally, we tested the acute toxicity of E2F decoy ODN in monkeys, and no apparent side-effects were detected. Here, we report the successful in vivo transfer of E2F decoy ODN using a hydrogel catheter to inhibit vascular lesion formation in balloon-injured porcine coronary artery without any apparent side-effects.

Development of safe and efficient novel nonviral gene transfer using ultrasound: enhancement of transfection efficiency of naked plasmid DNA in skeletal muscle

Although clinical trials of stimulation of angiogenesis by transfection of angiogenic growth factors using naked plasmid DNA or adenoviral vector have been successful, there are still unresolved problems for human gene therapy such as low transfection efficiency and safety. From this viewpoint, it is necessary to develop safe and efficient novel nonviral gene transfer methods. As therapeutic ultrasound induces cell membrane permeabilization, ultrasound irradiation might increase the transfection efficiency of naked plasmid DNA into skeletal muscle. Thus, we examined the transfection efficiency of naked plasmid DNA using ultrasound irradiation with echo contrast microbubble (Optison) in vitro and in vivo experiments. First, we examined the feasibility of ultrasound-mediated transfection of naked plasmid DNA into skeletal muscle cells. Luciferase plasmid mixed with or without Optison was transfected into cultured human skeletal muscle cells using ultrasound (1 MHz; 0.4 W(2)) for 30 s. Interestingly, luciferase activity was markedly increased in cells treated with Optison, while little luciferase activity could be detected without Optison (P < 0.01). Electron microscopy demonstrated the transient formation of holes (less than 5 microM) in the cell surface, which could possibly explain the rapid migration of the transgene into the cells. Next, we studied the in vivo transfection efficiency of naked plasmid DNA using ultrasound with Optison into skeletal muscle. Two days after transfection, luciferase activity in skeletal muscle transfected with Optison using ultrasound was significantly increased about 10-fold as compared with plasmid alone. Successful transfection was also confirmed by beta-galactosidase staining. Finally, we examined the feasibility of therapeutic angiogenesis using naked hepatocyte growth factor (HGF) plasmid in a rabbit ischemia model using the ultrasound-Optison method. Five weeks after transfection, the angiographic score and the number of capillary density in rabbits transfected with Optison using ultrasound was significantly increased as compared with HGF plasmid alone (P < 0.01), accompanied by a significant increase in blood flow and blood pressure ratio (P < 0.01). Overall, the ultrasound transfection method with Optison enhanced the transfection efficiency of naked plasmid DNA in vivo as well as in vitro. Transfection of HGF plasmid by the ultrasound-Optison method could be useful for safe clinical gene therapy to treat peripheral arterial disease without a viral vector system.

[HGF as a key molecule in cardiovascular diseases]

Hepatocyte growth factor(HGF) is focused as a powerful endothelial growth factor in the field of cardiovascular diseases. As its physiological role in atherosclerosis, restenosis, angiogenesis etc is very important, HGF-based new treatments for various diseases are expected. Clinical gene therapy for restenosis and ischemic diseases using VEGF gene have already performed in USA, and they could show beneficial effects of such strategies. In Japan, gene therapy using HGF gene for ASO has just begun in spring 2001. In near future, powerful therapeutic effects of HGF could applied to restenosis, graft failure, cardiomyopathy, cerebral vascular diseases, renal failure and so on.

Decoy oligodeoxynucleotides as novel cardiovascular drugs for cardiovascular disease

Gene therapy is emerging as a potential strategy in the treatment of cardiovascular disease such as restenosis after angioplasty, vascular bypass graft occlusion, and transplant coronary vasculopathy, for which no known effective therapy exists. One strategy for combatting disease processes is to target the transcriptional process. Application of DNA technology such as antisense strategy to regulate the transcription of disease-related genes in vivo has important therapeutic potential. Recently, transfection of cis-element double-stranded oligodeoxynucleotides (= decoy) as a powerful tool in a new class of antigene strategies for gene therapy was reported. Transfection of double-stranded oligodeoxynucleotides corresponding to cis sequence will result in the attenuation of authentic cis-trans interaction, leading to the removal of transfactors from the endogenous cis-elements with subsequent modulation of gene expression. This "decoy" strategy is not only a novel strategy for gene therapy as an antigene strategy, but also a powerful tool for the study of endogenous gene regulation in vivo as well as in vitro. In this review, we focus on the future potential of decoy oligodeoxynucleotide-based gene therapy in the treatment of cardiovascular disease.

Selective localization of G protein gamma5 subunit in the subventricular zone of the lateral ventricle and rostral migratory stream of the adult rat brain

G proteins play important roles in transmembrane signal transduction, and various isoforms of each subunit, alpha, beta and gamma, are highly expressed in the brain. The Ggamma5 subunit is a minor isoform in the adult brain, but we have previously shown it to be highly expressed in the proliferative region of the ventricular zone in the rat embryonic brain. We show here that Ggamma5 is also selectively localized in a proliferative region in the adult rat brain, including the subventricular zone of the lateral ventricle and rostral migratory stream. The Galphai2 subunit colocalized with Ggamma5 in these regions, the two subunits being present in neuronal precursors and ependymal cells but not in proliferating astrocytes. In addition, intense staining of Ggamma5 was seen in axons of the olfactory neurons, which are known to regenerate. These results suggest specific roles for Ggamma5 in precursor cells during neurogenesis so that this isoform might be a useful biological marker.

Galpha11 induces caspase-mediated proteolytic activation of Rho-associated kinase, ROCK-I, in HeLa cells

Expression of the constitutively active mutant of Galpha(11) (Galpha(11)QL) induces the formation of vinculin-containing focal adhesion-like structures in HeLa cells. This was found to be inhibited by Y-27632, a specific inhibitor of Rho-associated kinases (ROCK), but not by co-expression with a dominant negative mutant of RhoA, suggesting Rho-independent activation of ROCK by Galpha(11)QL. Investigation of trypan blue exclusion and immunocytochemistry with an antibody against cleaved caspase revealed the cellular phenotype of Galpha(11)QL-expressing cells to be identical to that displayed by cells undergoing apoptosis, and the caspase inhibitor zVAD-fmk blocked all morphological changes induced by Galpha(11)QL. Transfection of Galpha(11)QL induced cleavage of ROCK-I, and this proteolysis was also prevented by zVAD-fmk. ROCK-I C-terminally truncated at its authentic caspase sites also induced the formation of vinculin-containing focal adhesion-like structures. In addition, cleavage of ROCK-I was observed when cells overexpressing m1 muscarinic acetylcholine receptors were stimulated with carbachol. These results suggest that Galpha(11) induces proteolytic activation of ROCK-I by caspase and thereby regulates the actin cytoskeleton during apoptosis.