Construction of a recombinant adenovirus vector expressing IL-18BP/IL-4 fusion gene and the anti-inflammatory effect induced by this gene on lipopolysaccharide-stimulated synovial fibroblasts

Suppression of Th1 and Th17 Responses and Induction of Treg Responses by IL-18-Expressing Plasmid Gene Combined with IL-4 on Collagen-Induced Arthritis

OBJECTIVES

IL-18 is a proinflammatory cytokine with multiple immunoregulatory properties. We studied the effect of IL-18 gene therapy on the development of murine collagen-induced arthritis (CIA).

METHODS

Plasmid pCAGGS-IL-18 along or in combination with IL-10 or IL-4 was administered to CIA mice. The incidence and severity of arthritis of the paws were determined by a visual scale. Joint destruction was determined by histology. The levels of a panel of cytokines and transcription factors in the synovium were determined by reverse transcription polymerase chain reaction and quantitative RT-PCR. Quantitative RT-PCR was employed to detect the mRNA expression of TLRs and their pathway on the surface of DCs.

RESULTS

IL-18 gene therapy had no therapeutic effect on CIA mice. Additional coadministration with low dosage of recombinant IL-4 ameliorated the disease progression. Histopathological examination of the joints showed intact cartilage surface in IL-18 gene combined with IL-4-treated mice. The synovium of IL-18 gene combined with rIL4-treated mice had lower expression of TNF-α, IFN-γ, and IL-17 and higher expression of IL-10. The mechanism of this response appeared to involve modulation of transcription factors FoxP3 and GATA-3. The DCs in the spleen and lymph nodes of IL-18 gene combined with rIL4-treated mice had lower expression of TLR2, MyD88, and NF-kB.

CONCLUSIONS

Our findings indicate that pIL-18 gene combined with IL-4 ameliorates arthritis in the CIA mouse by suppression of Th1 and Th17 cytokines and increasing expression of FoxP3 and GATA-3. The plasmid backbone and multiple immunoregulatory properties of IL-18 appear to play a major role in the pIL-18 coadministration with rIL-4-mediated immunomodulation of arthritis through blocking the TLR2/MyD88/NF-kappa B signaling pathway.

The pathogenic role of angiogenesis in rheumatoid arthritis

Angiogenesis is the formation of new capillaries from pre-existing vasculature, which plays a critical role in the pathogenesis of several inflammatory autoimmune diseases such as rheumatoid arthritis (RA), spondyloarthropathies, psoriasis, systemic lupus erythematosus, systemic sclerosis, and atherosclerosis. In RA, excessive migration of circulating leukocytes into the inflamed joint necessitates formation of new blood vessels to provide nutrients and oxygen to the hypertrophic joint. The dominance of the pro-angiogenic factors over the endogenous angiostatic mediators triggers angiogenesis. In this review article, we highlight the underlying mechanisms by which cells present in the RA synovial tissue are modulated to secrete pro-angiogenic factors. We focus on the significance of pro-angiogenic factors such as growth factors, hypoxia-inducible factors, cytokines, chemokines, matrix metalloproteinases, and adhesion molecules on RA pathogenesis. As pro-angiogenic factors are primarily produced from RA synovial tissue macrophages and fibroblasts, we emphasize the key role of RA synovial tissue lining layer in maintaining synovitis through neovascularization. Lastly, we summarize the specific approaches utilized to target angiogenesis. We conclude that the formation of new blood vessels plays an indispensable role in RA progression. However, since the function of several pro-angiogenic mediators is cross regulated, discovering novel approaches to target multiple cascades or selecting an upstream cascade that impairs the activity of a number of pro-angiogenic factors may provide a promising strategy for RA therapy.

Infection by Cx43 adenovirus increased chemotherapy sensitivity in human gastric cancer BGC-823 cells: not involving in induction of cell apoptosis

BACKGROUND AND OBJECTIVE

There is a lower basal expression of Connexin43 (Cx43) in human gastric cancer BGC-823 cells. In the present study, BGC-823 cells were transfected with recombinant Cx43 adenovirus plasmid vector, and we explored the influences of Cx43 expression on cell proliferation, chemo-sensitivity, colony forming ability, invasion ability and apoptosis. Moreover, we also determined the expression of Pgp, Cx43, as well as apoptosis-related proteins (bcl-2, bax, caspase3 and caspase 9).

METHODS

MTT assay was performed to determine the proliferation of BGC-823 cells before and after Cx43 transfection. The influences of Cx43 infection on sensitivity of chemotherapy (including Doxorubicin, fluorouracil, oxaliplatin) were detected by MTT assay. Expression levels of Pgp, Cx43, as well as apoptosis-related proteins (bcl-2, bax, caspase-3 and caspase-9) in BGC-823 cells were determined by Western blotting analysis before and after the infection with Cx43 adenovirus. MDR expression was determined by RT-PCR before and after Cx43 infection. Invasive ability was detected by invasion chamber. Influence of Cx43 adenovirus infection on apoptosis of BGC-823 cells was determined by flow cytometry.

RESULTS

After infection by Cx43 adenovirus, colony forming rate and invasive ability of BGC-823 cells were decreased. Flow cytometry results revealed that cell apoptosis were insignificantly increased. The data of MTT assay revealed that infection with Cx43 adenovirus, cell proliferation ability decreased and sensitivity to chemotherapy drugs (including doxorubicin, fluorouracil, oxaliplatin) increased. Results of Western blotting analysis revealed that increasing expression levels of Cx43, decreasing expression levels of Pgp, and insignificant changes of bcl-2, bax, caspase3 and caspase 9 were detected. RT-PCR revealed the expression of MDR1 gene, the gene encoding Pgp, decreased significantly (p<0.05).

CONCLUSION

The human gastric cancer BGC-823 cells were infected with Cx43-IRES2-EGFP recombinant adenovirus vector. Colony formation, invasive ability and cell proliferation all decreased, whereas chemo-sensitivity increased in Cx43 infected BGC-823 cells. The increasing Cx43 expression was accompanied by decreasing Pgp expression and MDR1 m RNA levels. However, apoptosis-related proteins (bcl-2, bax, caspase3 and caspase 9) and cell apoptosis increased insignificantly. All results demonstrated that Cx43 may be negatively regulated the development, invasion and metastasis of gastric cancers, however, it had no obvious relationship with tumor cell apoptosis.

The protective effect of intrasplenic transplantation of Ad-IL-18BP/IL-4 gene-modified fetal hepatocytes on ConA-induced hepatitis in mice

Background

Concanavalin A (ConA)-induced hepatitis is an experimental murine model mirroring the pathology of human autoimmune hepatitis.

Aim

To investigate the effects of intrasplenically transplanted fetal hepatocytes (BNL.CL2) transfected with recombinant adenovirus vector expressing the IL-18 binding protein (IL-18BP) and IL-4 fusion protein on ConA-induced hepatitis in mice.

Methods

Ad-IL-18BP/IL-4 was used to infect BNL.CL2 cells. IL-4 and IL-18BP fusion protein expression were detected by ELISA and Western blotting. BNL.CL2 cells infected with Ad-IL-18BP/IL-4 were intrasplenically transplanted into mice. After 10 days, mice were injected with ConA (15 mg/kg), and sacrificed 18 hours later. Liver injury was assessed by serum transaminase and liver histology. TNF-α, IL-18, IL-4, IL-10, IL-12p70 and monocyte-chemoattracting protein (MCP)-1 levels in serum and liver homogenates were detected by ELISA. Signaling molecules in liver homogenates were analyzed by Western blotting.

Results

Ad-IL-18BP/IL-4 effectively expressed the IL-18BP/IL-4 fusion protein for more than 14 days in BNL.CL12 cells. Treatment of mice with Ad-IL-18BP/IL-4-BNL.CL2 before ConA injection significantly reduced the elevated plasma levels of transaminases compared with ConA control groups. TNF-α, IL-18, IL-12p70 and MCP-1 levels in serum and liver homogenates from mice transplanted with Ad-IL-18BP/IL-4-BNL.CL2 were lower and IL-4 and IL-10 levels were higher than control groups. Phosphorylation levels of NF-κB p65, AKT, p38 and JNK1/2 in liver homogenates were markedly suppressed by Ad-IL-18BP/IL-4.

Conclusions

Ad-IL-18BP/IL-4 was effectively transfected into mouse BNL.CL2 cells. Intrasplenic transplantation of Ad-IL-18BP/IL-4-BNL.CL12 cells alleviated the severity of inflammation in ConA-induced experimental hepatitis and provides a useful basis for the targeted gene therapy of liver disease.

Inhibition of inflammatory mediators and related signaling pathways by macrophage-stimulating protein in rheumatoid arthritis synovial fibroblasts

OBJECTIVE

To evaluate the mechanism of macrophage-stimulating protein (MSP)-mediated inhibition of inflammatory cytokine and chemokine production in rheumatoid arthritis synovial fibroblasts (RASF).

MATERIALS AND METHODS

RASF were treated with different concentrations (0, 0.5, 1, 5 and 10 ng/ml) of MSP with or without 1 μg/mL lipopolysaccharide (LPS). The protein expressions of IL-1β, TNF-α, IL-18, MIP-1, MCP-1, RANTES and PGE(2) were analyzed by enzyme-linked immunosorbent assays (ELISA). The total nitric oxide (NO) concentration was determined using the Griess reaction. The protein expressions of iNOS, COX-2, NF-κB(p-p65), IKB-α, IKB-β, p-P38, p-Erk1/2 (P-P42/44) and p-AKT were detected by Western blotting.

RESULTS

MSP markedly inhibited expression of inflammatory cytokines (IL-1β, TNF-α and IL-18), chemokines (MIP-1, MCP-1 and RANTES) and iNOS, NO, COX-2 and PGE(2) in RASF stimulated by LPS. MSP treatment decreased expressions of p-IκBα, p-IKBβ and p-P65 in RASF in a concentration-dependent manner. Expressions of p-AKT, p-p38 and p-Erk1/2 were also inhibited markedly in RASF stimulated by LPS after treatment with MSP in a concentration-dependent manner.

CONCLUSION

MSP could inhibit the inflammatory cycle by suppressing inflammatory mediators and activation of NF-κB as well. The inhibitory effect of MSP on LPS-stimulated RASF may act through suppression of multiple signals such as the PI3K/AKT and/or MAPK pathways.