| Acute inflammatory reactions are defined as a series of tissue reactions that occur within the first few hours after the occurrence of injury.How to quickly and effectively treat acute inflammation has been an important problem in clinical and medical laboratory research.RNA interference(RNAi)refers to the biodegradation of target RNA by post transcriptional gene silencing,which leads to the biological process of terminating the translation.Introducing the exogenous small interfering RNA(siRNA)into the corresponding inflammatory cells and combining it with the corresponding inflammatory factors’ mRNA to prevent its further translation of proteins can effectively reduce the expression of inflammatory related factors to relieve the inflammatory symptoms.How to efficiently load the siRNA and deliver it to the corresponding target tissue is an important challenge for gene therapy.Based on this,the first chapter is an overview of acute inflammation,RNA interference and siRNA delivery.We designed three siRNA delivery systems to treat the three corresponding acute inflammations: acute lung injury(ALI),myocardial ischemia reperfusion injury(IRI)and acute liver failure(ALF)in following three chapters.1.Mucus/cell membrane dual-penetrating,macrophage-targeting polyplexes mediate potent anti-inflammatory RNA interference against acute lung injuryTrans-mucosal delivery of anti-inflammatory siRNA into pulmonary alveolar macrophages represents a promising modality for the treatment of acute lung injury(ALI).However,its therapeutic efficacy is often hurdled by the lack of effective carriers that can simultaneously overcome the mucosal barrier and the macrophage membrane barrier that often pose opposing requirements for materials development.Herein,we developed mucus/cell membrane dual-penetrating,macrophage-targeting polyplexes which enabled efficient intratracheal delivery of TNF-α siRNA(si TNF-α)to attenuate lung inflammation in mice experiencing lipopolysaccharide(LPS)-induced ALI.P-G@Zn,a cationic helical polypeptide bearing both guanidine and zinc dipicolylamine(Zn-DPA)side charged groups,was designed to condense si TNF-α and promote macrophage internalization due to its helicity-dependent membrane activity.Coating of the polyplexes with charge-neutralizing carboxylated mannan(Man-COOH)greatly contributed to the enhanced mucus penetration potency due to shielding of the electrostatic adhesive interactions with the mucus,and it cooperatively enabled active targeting to alveolar macrophages with over-expressed mannose receptors to potentiate the delivery efficiency of si TNF-α into macrophages.As such,intratracheally administered Man-COOH/P-G@Zn/si TNF-α polyplexes afforded notable TNF-α silencing by ~75% in inflamed lung tissues at 500 μg siRNA/kg,and demonstrated potent anti-inflammatory performance to treat ALI.2.Zn-DPA functionalized poly(β-amino ester)mediate potent anti-inflammatory RNA interference against myocardial ischemia-reperfusionPoly(β-amino ester)(PBAE),as a biodegradable cationic gene carrier,has been widely concerned for its high biocompatibility,low surface potential and good serum stability.However,lower surface potential leads to poor siRNA loading and cell uptake capacity of PBAE.Therefore,we developed Zn-DPA-functionalized PBAE(P-OH@Zn).PBAE’s abilities of siRNA load and cell uptake were increased via the coordination of Zn-DPA and phosphoric acid groups,while its low surface potential and good biocompatibility were maintained.In the inflammatory model of myocardial ischemia reperfusion injury,intravenous injection of P-OH@Zn/siRAGE complex(500 g siRNA/kg)showed high mRNA silencing efficiency.The complex decreased about 80% RAGE mRNA expression at the ligation of the heart,to significantly reduce the expression of inflammatory cytokines in reperfusion injury,effectively relieve inflammatory symptoms,and restore the cardiac ejection function to the normal level.3.Macrophage-targeting and reactive oxygen species(ROS)-responsive nanopolyplexes mediate anti-inflammatory siRNA delivery against acute liver failureAs one of the intractable challenges in the clinic,the treatment of acute liver failure(ALF)is limited to high mortality and resource cost.RNA interference(RNAi)provides a new modality for the anti-inflammatory therapy of ALF,while its therapeutic efficacy is greatly hampered by the lack of effective carriers to cooperatively overcome the various systemic barriers.Herein,we developed macrophage-targeting and reactive oxygen species(ROS)-responsive polyplexes to enable efficient systemic delivery of TNF-α siRNA(si TNF-α)to attenuate hepatic inflammation in mice bearing ALF.Se-PEI,obtained from the cross-linking of 600 Da polyethylenimine(PEI)via the ROS-responsive diselenide bond,was developed to condense si TNF-α,and the obtained polyplexes were further coated with carboxylated mannan(Man-COOH).Man-COOH coating allowed active targeting of polyplexes to macrophages with over-expressed mannose receptors(MRs),and it shielded the surface positive charges to enhance the serum stability of polyplexes.Se-PEI could be degraded by ROS in inflammatory macrophages to promote intracellular siRNA release to potentiate the gene knockdown efficiency,and at the meantime reduce the material cytotoxicity associated with high molecular weight.As such,i.v.injected Man-COOH/Se-PEI/si TNF-α polyplexes afforded notable TNF-α silencing by ~80% in inflamed liver tissues at 500 μg siRNA/kg,and notably reduced serum TNF-α levels to achieve potent anti-inflammatory performance against ALF. |
