Expression Of Recombinant Vasoactive Intestinal Peptide In Yeast And It's Efficacy For Treating Asthma In Rat

Asthma is a common form of a airways chronic disease that is characterized by reversible airflow obstruction,airway inflammation,persistent airway hyperreactivity and airway remodeling.Although there are many kinds of medicines for treating asthma,including use anti-inflammatory drugs and bronchiectasis,there is no single medication that is effective against both the inflammatory and bronchoconstrictive components of asthma until today.Vasoactive intestinal peptide(VIP)is a neural polypeptide that composed of 28 amino acids,which exerts a wide range of biological actions,on the one hand it act as pulmonary and coronary vasodilatation,bronchodilation,and also has anti-inflammatory effects;on the other hand,VIP exerts functions as a potent immunomodulator,thus VIP has significant therapeutic potential in the treatment of asthma.However,VIP-based drugs are not yet in clinical use because of the shot half-life period.In order to solve this problem,this study designed VIP and human serum albumin(HSA)fusion protein to prolong its half-life in vivo without affecting its efficacy of treating asthma.We connected VIP and HSA by gene engineering technique to get the fusion gene and construct the eukaryotic expression vector pPinka HC-VIP-HSA,preferably choose Pichia pastoris strain for expression,analysis the expression product by SDS-PAGE and select 1-4 strain for expand expansion,the concentration of purified VIP-HSA recombinant protein is about 0.2mg/mL.In order to research the VIP-HSA recombinant protein efficacy of treating asthma,we use ovalbumin as the sensitizing agent to construct asthma model of Wister rat.VIP-HSA recombinant protein showed the efficacy of relieve asthma symptoms and reduce IgE level in serum,the histological examination of the lungs revealed no obvious pathological changes compared with asthma modeling group.In addition,we set up a group of rats to inject VIP-HSA recombinant protein every other day and achieve the same effect.The result demonstrates that VIP-HSA recombinant protein can not only maintain its efficacy of treating asthma,but also prolong its half-life in vivo.However,the accurate measurement of its half-life in vivo is still needed and its effective against bronchoconstrictive and immunoregulation remains to be further studied.