| Obesity has long been a threat to human health.Studies have shown that overweight weight is linked to the pathogenesis of many diseases,including high blood pressure,hyperlipidemia,diabetes and certain types of cancer.The treatment of obesity by chemical drugs is often associated with strong side effects,which can be difficult to bear and result in poor nutrition.In recent years,the rapid development of biotechnology drugs has brought opportunities for the use of biotechnology drugs to treat obesity.Ciliary neurotrophic factor(CNTF)is a molecular weight of about 20 kDa,consisting of four anti-phase alpha-helical structures.Its physiological function in vivo is mainly involved in the growth of neurons and repair of damaged neurons.In recent years,clinical studies have found that CNTF can inhibit the physiological activity of individual food intake during the treatment of nerve injury.The mechanism by which CNTF inhibits individual appetite is mainly through the receptor that acts on the hypothalamus.Compared to leptin,another appetite-suppressing molecule,CNTF also has an appetite suppressant effect on food-induced obesity,while leptin does not.And food induced obesity is more closely related to the obesity pathogenesis of human.Therefore,CNTF protein shows great application prospect in the treatment of obesity disease.Subsequently,the study found that CNTF had a brief period of metabolic half-life in the blood in the body.The study of pharmacokinetics of rats showed that the half-life of the blood removal of CNTF was less than 10 minutes,which greatly restricted the clinical application of CNTF.Therefore,the development of long-term CNTF is the main direction for the research on the treatment of obesity.Polyethylene glycol(PEG)modification is one of the main protein drugs currently long-term strategy,to high hydrophilic polyethylene glycol modification and surface active functional groups of protein coupling,coupling material compared to the original protein has a larger molecular volume and stronger resistance to cells,the protease degradation ability,then extend the reserved half-life in blood.The method of polyethylene glycol modification has been developed in many ways.The key to the modification of polyethylene glycol in protein is the selection optimization of the modified mode and the purification after modification.In addition,transferrin has a longer metabolic half-life in the body,about 10 days.It also benefits from the high expression of transferritin receptors on the blood-brain barrier,so transferrin can participate in the exchange of substances in the brain and blood.Therefore,the research on the brain drug delivery based on transferrin is the main research topic in the current brain targeting drug delivery.Considering the metabolism of CNTF and its short half-life,at the same time,its work area exists in the hypothalamus and brain,so the preparation,characterization and the research purpose of this study is to compare the polyethylene glycol modified CNTF and transferrin coupling CNTF activity,physical and chemical properties of CNTF in vitro and in vivo biological activity,etc.In this article,through the study of the modification of PEG20 k of CNTF and through PEG5k and transferrin coupling,coupling product relative to the CNTF protein,apparent molecular volume and molecular size was significantly increased in water phase,in the aspect of biological activity and antibody affinity have varying degrees of decline(cell activity and antibody affinity PEG20k-CNTF were 50.6%and 3.8%respectively,Tf-PEG5k-CNTF is 65.8%and 89.9%).The pharmacokinetic results showed that CNTF,PEG20k-CNTF and Tf-PEG5k-CNTF had a metabolic half-life in SD rats(0.25 ± 0.12,5.34 ± 0.26 and 8.65 ± 0.60 hours),respectively.Mice showed significant improvement in their ability to suppress food intake compared to CNTF. |
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