Different effects of antisense RelA p65 and NF-kappaB1 p50 oligonucleotides on the nuclear factor-kappaB mediated expression of ICAM-1 in human coronary endothelial and smooth muscle cells

Regulation of activity of transcription factor NF-κB by synthetic oligonucleotides

Eukaryotic dimeric nuclear factor-κB (NF-κB) is one of the main transcription factors that activate expression of genes, products of which play the key role in development of cardiovascular pathologies, carcinogenesis, and inflammatory and viral diseases. In this review, the main attention is given to modulation of the transcription factor NF-κB activity by antisense oligonucleotides and oligonucleotide decoys. Also, current concepts about interactions between NF-κB dimers and DNA and general problems that arise in experimental use of synthetic oligonucleotides in vivo are discussed.

Direct inhibitory effects of Ganciclovir on ICAM-1 expression and proliferation in human coronary vascular cells (SI/MPL-ratio: >1)

Background

Treatment of the human cytomegalovirus (HCMV) infection with ganciclovir has beneficial indirect effects on the complex interactions of HCMV with restenosis, atherosclerosis, and transplant vascular sclerosis. The current study reports on direct effects of ganciclovir on expression of ICAM-1 and cell proliferation, key events of coronary atherosclerosis/restenosis. A potential clinical relevance of the data will be evaluated with the help of SI/MPL-ratio’s.

Material/Methods

Definition of the SI/MPL-ratio: relation between significant inhibitory effects in vitro/ex vivo and the maximal plasma level after systemic administration in vivo (ganciclovir: 9 μg/ml). Part I of the study investigated in cytoflow studies the effect of ganciclovir (0.05–5000 μg/mL) on TNF-a induced expression of intercellular adhesion molecule 1 (ICAM-1) in endothelial cells derived from umbilical veins (HUVEC), human coronary endothelial cells (HCAEC), and human coronary smooth muscle cells (HCMSMC). Part II of the study analysed the effect of ganciclovir (0.05–5000 μg/mL) on cell proliferation (HUVEC, HCAEC, and HCMSMC). In part III cytotoxic effects of ganciclovir (0.05–5000 μg/mL) were studied (HUVEC, HCAEC, and HCMSMC).

Results

Ganciclovir caused slight but significant inhibitory effects on expression of ICAM-1 in HUVEC, HCAEC, and HCMSMC. In all three cell types studied strong dose depending significant antiproliferative effects of ganciclovir were detected. Partially, the antiproliferative effects of ganciclovir were caused by cytotoxic effects.

Conclusions

SI/MPL-ratio’s >1 in HCAEC and HCMSMC indicate that the inhibitory effects of gancliclovir on ICAM-1-expression and cell proliferation may only be expected in vivo following local high dose administration e.g. in drug eluting stents (DES).

Atherogenic Lipids Induce Adhesion of Human Coronary Artery Smooth Muscle Cells to Macrophages by Up-regulating Chemokine CX3CL1 on Smooth Muscle Cells in a TNFα-NFκB-dependent Manner

Recent genetic evidence has implicated the adhesive chemokine CX3CL1 and its leukocyte receptor CX3CR1 in atherosclerosis. We previously proposed a mechanism involving foam cell anchorage to vascular smooth muscle cells because: 1) CX3CL1 and CX3CR1 are expressed by both cell types in mouse and human atherosclerotic lesions; 2) foam cells are reduced in lesions in cx3cr1(-/-)apoE(-/-) mice; and 3) proatherogenic lipids (oxidized low density lipoprotein [oxLDL] and oxidized linoleic acid derivatives) induce adhesion of primary human macrophages to primary human coronary artery smooth muscle cells (CASMCs) in vitro in a macrophage CX3CR1-dependent manner. Here we analyze this concept further by testing whether atherogenic lipids regulate expression and function of CX3CL1 and CX3CR1 on CASMCs. We found that both oxLDL and oxidized linoleic acid derivatives indirectly up-regulated CASMC CX3CL1 at both the protein and mRNA levels through an autocrine feedback loop involving tumor necrosis factor alpha production and NF-kappaB signaling. Oxidized lipids also up-regulated CASMC CX3CR1 but through a different mechanism. Oxidized lipid stimulation also increased adhesion of macrophages to CASMCs when CASMCs were stimulated prior to assay, and a synergistic pro-adhesive effect was observed when both cell types were prestimulated. Selective inhibition with a CX3CL1-specific blocking antibody indicated that adhesion was strongly CASMC CX3CL1-dependent. These findings support the hypothesis that CX3CR1 and CX3CL1 mediate heterotypic anchorage of foam cells to CASMCs in the context of atherosclerosis and suggest that this chemokine/chemokine receptor pair may be considered as a pro-inflammatory target for therapeutic intervention in atherosclerotic cardiovascular disease.

Sirolimus inhibits key events of restenosis in vitro/ex vivo: evaluation of the clinical relevance of the data by SI/MPL- and SI/DES-ratios

Background

Sirolimus (SRL, Rapamycin) has been used successfully to inhibit restenosis both in drug eluting stents (DES) and after systemic application. The current study reports on the effects of SRL in various human in vitro/ex vivo models and evaluates the theoretical clinical relevance of the data by SI/MPL- and SI/DES-ratio's.

Methods

Definition of the SI/MPL-ratio: relation between significant inhibitory effects in vitro/ex vivo and the maximal plasma level after systemic administration in vivo (6.4 ng/ml for SRL). Definition of the SI/DES-ratio: relation between significant inhibitory effects in vitro/ex vivo and the drug concentration in DES (7.5 mg/ml in the ISAR drug-eluting stent platform). Part I of the study investigated in cytoflow studies the effect of SRL (0.01–1000 ng/ml) on TNF-α induced expression of intercellular adhesion molecule 1 (ICAM-1) in human coronary endothelial cells (HCAEC) and human coronary smooth muscle cells (HCMSMC). Part II of the study analysed the effect of SRL (0.01–1000 ng/ml) on cell migration of HCMSMC. In part III, IV, and V of the study ex vivo angioplasty (9 bar) was carried out in a human organ culture model (HOC-model). SRL (50 ng/ml) was added for a period of 21 days, after 21 and 56 days cell proliferation, apoptosis, and neointimal hyperplasia was studied.

Results

Expression of ICAM-1 was significantly inhibited both in HCAEC (SRL ≥ 0.01 ng/ml) and HCMSMC (SRL ≥ 10 ng/ml). SRL in concentrations ≥ 0.1 ng/ml significantly inhibited migration of HCMSMC. Cell proliferation and neointimal hyperplasia was inhibited at day 21 and day 56, significance (p < 0.01) was achieved for the inhibitory effect on cell proliferation in the media at day 21. The number of apoptotic cells was always below 1%.

Conclusion

SI/MPL-ratio's ≤ 1 (ICAM-1 expression, cell migration) characterize inhibitory effects of SRL that can be theoretically expected both after systemic and local high dose administration, a SI/MPL-ratio of 7.81 (cell proliferation) represents an effect that was achieved with drug concentrations 7.81-times the MPL. SI/DES-ratio's between 10^-6 and 10^-8 indicate that the described inhibitory effects of SRL have been detected with micro to nano parts of the SRL concentration in the ISAR drug-eluting stent platform. Drug concentrations in DES will be a central issue in the future.

Alleviation of neuropathic pain by intrathecal injection of antisense oligonucleotides to p65 subunit of NF-kappaB

BACKGROUND

Treatment of neuropathic pain remains a challenge. The current study investigated the therapeutic effect of intrathecal administration of NF-kappaB antisense oligodeoxynucleotides (ODNs) on mechanical allodynia and thermal hyperalgesia in a chronic constriction injury (CCI) model of rats.

METHODS

Lumbar intrathecal catheters were implanted in male Sprague-Dawley rats and a CCI model was established. Thermal and mechanical nociceptive thresholds were assessed with paw withdrawal latency (PWL) to radiant heat and von Frey filaments. The phosphorothioate-modified antisense ODNs to p65 subunit of NF-kappaB were administered intrathecally on each of five consecutive days post-CCI. Nuclear NF-kappaB p65 expression was assessed by western blot.

RESULTS

CCI induced mechanical allodynia and thermal hyperalgesia and significantly increased NF-kappaB p65 protein expression. Intrathecal injection of antisense ODN markedly suppressed the expression of NF-kappaB p65 protein and significantly attenuated CCI-induced mechanical allodynia and thermal hyperalgesia.

CONCLUSION

The activation of NF-kappaB pathway may contribute to neuropathic pain in CCI rats. Suppression of NF-kappaB could be a potential new strategy for the treatment of neuropathic pain.

IKKalpha and IKKbeta function in TNFalpha-stimulated adhesion molecule expression in human aortic smooth muscle cells

The role of NFkappaB and it's upstream kinases in regulating adhesion molecule expression in the smooth muscle of the vasculature remains controversial. We therefore examined the effect of blocking the NFkappaB pathway on TNFalpha-stimulated ICAM-1 and VCAM-1 expression in primary cultures of human aortic smooth muscle cells using an adenoviral wild-type IkappaB alpha construct (Ad.IkappaB alpha) and dominant-negative IKKalpha (Ad.IKKalpha+/-) and IKKbeta (Ad.IKKbeta+/-) constructs. Ad.IkappaB alpha treatment was found to block NFkappaB DNA-binding, and thereby completely prevent TNFalpha-stimulated ICAM-1 and VCAM-1 expression without influencing IKK activity. Ad.IKKbeta+/- treatment completely inhibited TNFalpha-stimulated IKK kinase activity, IkappaB alpha degradation and NFkappaB DNA-binding in addition to completely blocking TNFalpha-stimulated ICAM-1 and VCAM-1 expression. Ad.IKKalpha+/- treatment however had no detectable effect on NFkappaB DNA-binding or ICAM-1 and VCAM-1 expression. Our results demonstrate that TNFalpha-stimulated ICAM-1 and VCAM-1 expression in human aortic smooth muscle cells is NFkappaB-dependent, that IKKbeta is a suitable target for drug therapy and Ad.IKKbeta+/- an effective inhibitor of TNFalpha-stimulated ICAM-1 and VCAM-1 expression.

A beginner's guide to NF-kappaB signaling pathways

Nuclear factor kappaB (NF-kappaB) belongs to a family of heterodimeric transcription factors that play a key role in inflammatory and stress responses as well as in tumor cell resistance to apoptosis. These effects are due to the NF-kappaB-dependent transcription of many proinflammatory and antiapoptotic genes, whose products ensure various cell responses to environmental conditions. The signal transduction pathways leading to NF-kappaB activation are well characterized, and the different steps implicated in these pathways involve proteins that could constitute targets for NF-kappaB inhibition. Several inhibitors aiming to prevent NF-kappaB activity and thus the transcription of target genes are studied, and a few compounds seem particularly promising. We try here to summarize the advantages that can issue from various studies on NF-kappaB.

Tumor necrosis factor-alpha-induced CTACK/CCL27 (cutaneous T-cell-attracting chemokine) production in keratinocytes is controlled by nuclear factor kappaB

CTACK/CCL27 is pivotal in mediating the migration of lymphocytes into the skin, through the binding to the chemokine receptor CCR10. CCL27 is continuously expressed by keratinocytes, but highly upregulated in inflammatory skin diseases such as atopic dermatitis and psoriasis. CCL27 can be induced in cultured keratinocytes by tumor necrosis factor (TNF)-alpha, which is also known to induce activity of the transcription factor NF-kappaB. NF-kappaB plays a vital role in controlling inflammation through its regulation of transcription of chemokines and pro-inflammatory cytokines. We show here that inhibition of NF-kappaB with the non-specific NF-kappaB inhibitors SSC (sodium salicylate), DCIC (3,4-dichloroisocoumarin) and PAO (phenylarsine oxide) results in a downregulation of TNF-alpha-induced CCL27 production. To substantiate the result and to investigate the role of NF-kappaB we investigated if specific antisense oligonucleotides against the p50 and p65 subunits of NF-kappaB had the same effect. Inhibition of either p50 or p65 production with antisense oligonucleotides resulted in a significant downregulation of TNF-alpha-induced CCL27 production. These results indicate that CCL27 expression is under the control of NF-kappaB, and that NF-kappaB, as indicated by others, may be an attractive target for therapy in inflammatory skin diseases.

Administration of antisense phosphorothioate oligonucleotide to the p65 subunit of NF-kappaB inhibits established asthmatic reaction in mice

The transcription factor, nuclear factor (NF)-kappaB, which transactivates various genes for proinflammatory cytokines and many other immunoregulatory genes, plays an important role in the regulation of various inflammatory diseases including asthma. Its increased activation has been demonstrated in the lungs after allergen challenge and in airway epithelial cells and macrophages of asthmatic patients. In the present study, we investigated whether the pretreatment with p65 antisense results in a significant inhibition of asthmatic reactions in a mouse model. Mice sensitized and challenged with ovalbumin (OVA) showed typical asthmatic reactions as follows: (1) an increase in the number of eosinophil in bronchoalveolar lavage fluid; (2) a marked influx of inflammatory cells into the lung around blood vessels and airways, and airway luminal narrowing; (3) the development of airway hyperresponsiveness; (4) the detection of TNF-alpha and Th2 cytokines, such as IL-4 and IL-5 in the bronchoalveolar lavage (BAL) fluid; and (5) detection of allergen-specific IgE and IgG in the serum. Two successive intravenous administration of p65 antisense before the last airway OVA challenge resulted in a significant inhibition of all asthmatic reactions, whereas the p65 nonsense did not produce such effects. In addition, the p65 antisense inhibition of asthmatic reaction appears to be due to the initial suppression of an allergen-specific IgE response, inducing degranulation of mast cells through the cross-linking of allergen-specific IgE. This study may provide evidence that NF-kappaB plays a critical role in the pathogenesis of asthma in mice.

p53 activates ICAM-1 (CD54) expression in an NF-kappaB-independent manner

Intercellular adhesion molecule-1 (ICAM-1) is a crucial receptor in the cell-cell interaction, a process central to the reaction to all forms of injury. Its expression is upregulated in response to a variety of inflammatory/immune mediators, including cellular stresses. The NF-kappaB signalling pathway is known to be important for activation of ICAM-1 transcription. Here we demonstrate that ICAM-1 induction represents a new cellular response to p53 activation and that NF-kappaB inhibition does not prevent the effect of p53 on ICAM-1 expression after DNA damage. Induction of ICAM-1 is abolished after treatment with the specific p53 inhibitor pifithrin-alpha and is abrogated in p53-deficient cell lines. Furthermore, we map two functional p53-responsive elements to the introns of the ICAM-1 gene, and show that they confer inducibility to p53 in a fashion similar to other p53 target genes. These results support an NF-kappaB-independent role for p53 in ICAM-1 regulation that may link p53 to ICAM-1 function in various physiological and pathological settings.