PARP-1 inhibitor reduces inflammation and oxidative stress in rats with chronic obstructive pulmonary disease by activating SIRT1-PGC-1α axis / 中国免疫学杂志

Objective:To establish an experimental model of chronic obstructive pulmonary disease(COPD)in rats,and explore whether polyadenosine diphosphate ribose polymerase-1(PARP-1)inhibitors regulate Sirtuin 1(SIRT1)and peroxisome proliferator-activated receptor-γ co-activator 1α(PGC-1α)to reduce inflammation and oxidative stress in COPD rats,and explore the possibility of SIRT1-PGC-1α axis as a new target of PARP-1 inhibitor.Methods:Twelve of 48 SD rats were randomly selected as healthy group,and the remaining rats were used to construct experimental models of COPD.Rats that were successfully modeled were randomly divided into model group,PARP-1 inhibitor treatment group and PARP-1 inhibitor+PGC-1α inhibitor group.HE staining was used to observe pathological changes of lung tissue,ELISA was used to detect levels of TNF-α,IL-6,IL-1β,malondialdehyde(MDA),superoxide dismutase(SOD)in rats lung tissue,fluorescence quantitative PCR was used to detect expression levels of SIRT1 and PGC-1α mRNA of rats in each group,Western blot was used to detect expressions of SIRT1 and PGC-1α proteins.Results:Lung tissue structure of rats in healthy group was complete,compared with healthy group,lung tissue of model group suffered structural damage,with a large number of inflammatory cells infiltrated,contents of TNF-α,IL-1β and IL-6 in alveolar lavage fluid were significantly increased,con-tent of MDA in serum was significantly increased,while content of SOD was significantly reduced,and expressions of SIRT1,PGC-1α mRNA and protein were significantly reduced;compared with model group,lung tissue structure of rats in PARP-1 inhibitor treatment group was recovered,and inflammatory cells were reduced,contents of TNF-α,IL-1β and IL-6 were significantly reduced,content of MDA in serum was significantly reduced,while content of SOD was significantly increased,and expressions of SIRT1,PGC-1α mRNA and protein were significantly increased;compared with PARP-1 inhibitor treatment group,the number of inflammatory cells in PARP-1 inhibitor+PGC-1α inhibitor group was increased,contents of TNF-α,IL-1β and IL-6 were significantly increased,content of MDA in serum was significantly increased,while content of SOD was significantly reduced,expressions of SIRT1,PGC-1α mRNA and protein were significantly reduced.Conclusion:PARP-1 inhibitors can alleviate inflammation and oxidative stress by activating SIRT1-PGC-1α axis,thereby effectively alleviating COPD.

Optimization of unnatural amino acid incorporation in collagen and the cross-linking through thioether bond / 生物工程学报

The source of recombinant collagen is clean, and it has the advantages of flexible sequence design, high yield and high purity, so it has a wide application prospect as biomaterials in tissue engineering and other fields. However, how to promote the cross-linking of recombinant collagen molecules and make them form a more stable spatial structure is the difficulty to be overcome in the design of recombinant collagen nanomaterials. Unnatural amino acid O-(2-bromoethyl)-tyrosine was incorporated into collagen by two-plasmid expression system. The results showed that high-purity collagen incorporated with unnatural amino acid could be obtained by induction with final concentration of 0.5 mmol/L IPTG and 0.06% arabinose at 25 °C for 24 hours. The intermolecular cross-linking through thioether bond was formed between collagen molecule incorporated with unnatural amino acid and collagen molecule with cysteine mutation in pH 9.0 NH4HCO3 buffer, which formed aggregates with the largest molecular size up to 1 micrometre. The results pave the way for the design of recombinant collagen biomaterials.