Effects of antagonistic peptide specifically binding to second extracellular loop of CCR5 on inflammatory cell infiltration and TNF-α expression in lung tissues of asthmatic mice induced by OVA / 中国病理生理杂志

AIM: To investigate the effects of antagonistic peptide specifically binding to the second extracellular loop of CC chemokine receptor 5 (CCR5) on inflammatory cell infiltration and TNF-α expression in lung tissues of asthmatic mice.METHODS: The asthmatic model of BALB/c mice was induced by ovalbumin (OVA) and the optimal sensitization concentration of OVA was screened.After modeling, the mice were intervened by gradual concentrations of antagonistic peptide via tail-vein injection.The pathocytological analysis and grading were performed in the lung tissues with HE staining.The expression of TNF-α at mRNA and protein levels in the lung tissues was determined by real-time PCR and Western blot.RESULTS: The optimal concentration of OVA was 500 mg/L (0.1 mL) as this concentration of OVA stably induced moderate degree of inflammation in the BALB/c mice.Treatment with different concentrations (1.5 g/L, 2.5 g/L and 3.5 g/L) of antagonistic peptide at 0.2 mL through tail-vein injection inhibited the expression of TNF-α, and markedly reduced the degree of inflammation in the lung tissues.The optimal concentration of antagonistic peptide was 2.5 g/L as the lung inflammation degree in 2.5 g/L group alleviated by 2 grades, and the number of inflammatory cells was also significantly reduced.Moreover, the mRNA expression abundance of TNF-α was nearly decreased by 90%, and the protein expression of TNF-α was decreased by 70% compared with model group.Meanwhile, the use of antagonistic peptide at 2.5 g/L before OVA stimulation confirmed the preventive function to some degree.In this group, the lung inflammation degree alleviated by 1 grade, and the expression of TNF-α at both mRNA and protein levels decreased by nearly 50%.CONCLUSION: The antagonistic peptide of CCR5 effectively inhibits the expression of TNF-α and relieves the inflammation in the asthmatic mouse lung tissues in a concentration-dependent manner.

Effects of antagonistic peptides binding specifically with first and second extracellular loops of CCR5 on colitis rats induced by TNBS / 中国病理生理杂志

AIM:To study the effects of antagonistic peptides binding specifically with the first and second extracellular loops (ECL1 and ECL2) of C-C chemokine receptor 5 (CCR5) on the colitis rats induced by trinitrobenzenesulfonic acid (TNBS) and the mechanisms.METHODS:The colitis model of SD rats was induced by TNBS (100 mg/kg).The effects of 2 antagonistic peptides at different doses (ECL1:25, 35 and 45 mg/kg;ECL2:15, 25 and 35 mg/kg) on the model rats including the changes of disease activity index (DAI), colon macroscopic damage index (CMDI) and histological grading were observed.The mRNA and protein expression levels of TNF-α and COX-2 in the colonic mucosa were detected by real-time PCR and Western blot, respectively.RESULTS:Compared with model group, the changes of DAI, CMDI and histopathological injury of the rats treated with ECL2 antagonistic peptide HY at an appropriate dose were significantly reduced (P<0.05), and the protein and mRNA expression levels of TNF-α and COX-2 were significantly decreased (P<0.05).However, the effects of ECL1 antagonistic peptide GH on all scores and the expression levels of TNF-α and COX-2 were not obvious.CONCLUSION:ECL2 antagonistic peptide HY relieves TNBS-induced colitis in SD rats via down-regulating the expressions of TNF-α and COX-2 in the colonic mucosa, while the effect of ECL1 antagonist peptide GH was not obvious.

Panning and identification of antagonistic active peptides specifically bin-ding to the first and second extracellular membrane loops of rat CCR5 by technique of phage display peptide library / 中国病理生理杂志

[ ABSTRACT] AIM: To pan the active peptides which specifically bound to the first and second extracellular membrane loops of rat CC chemokine receptor 5 ( CCR5 ) .METHODS: The technique of phage display peptide library was used and binding ability of the peptides was identified.The amino acid sequences of the first and second extracellular loops of rat CCR5 were searched in the protein database and chemically synthesized corresponding linear peptides were used as targets in the biopanning.After 3 to 4 rounds of screening with Ph.D.TM-7 Phage Display Peptide Library were per-formed, the specific phages were collected and primarily identified by ELISA.RESULTS:The sequences of the peptides displayed on the selected phages were GHWKVWL and HYIDFRW, both of them exhibited positive in phage binding ELISA and the binding to phages and targets were concentration dependent and saturable.CONCLUSION:Two antagonis-tic active peptides specifically binding to CCR5 were successfully obtained by the technique of phage display peptide librar-y, and the binding ability to the first and second extracellular membrane loops of rat CCR5 were proved in vitro.