Medina Scott H, Li Sandra, Howard O M Zack, Dunlap Micah, Trivett Anna, Schneider Joel P, Oppenheim Joost J
Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
Laboratory of Molecular Immunoregulation, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
Biomaterials. 2015;53:545-53. doi: 10.1016/j.biomaterials.2015.02.125. Epub 2015 Mar 23.
DNA that encodes tumor-specific antigens represents potential immunostimulatory agents. However, rapid enzymatic degradation and fragmentation of DNA during administration can result in limited vector expression and, consequently, poor efficacy. These challenges have necessitated the use of novel strategies for DNA delivery. Herein, we study the ability of cationic self-assembling peptide hydrogels to encapsulate plasmid DNA, and enhance its immunostimulatory potential in vivo. The effect of network charge on the gel's ability to retain the DNA was assessed employing three gel-forming peptides that vary systematically in formal charge. The peptide HLT2, having a formal charge of +5 at neutral pH, was optimal in encapsulating microgram quantities of DNA with little effect on its rheological properties, allowing its effective syringe delivery in vivo. The plasmid, DNA(TA), encapsulated within these gels encodes for a melanoma-specific gp100 antigen fused to the alarmin protein adjuvant HMGN1. Implantation of DNA(TA)-loaded HLT2 gels into mice resulted in an acute inflammatory response with the presence of polymorphonuclear cells, which was followed by infiltrating macrophages. These cellular infiltrates aid in the processing of encapsulated DNA, promoting increased lymphoproliferation and producing an enhanced immune response mediated by CD4+/IFNγ+ expressing Th1 cells, and complemented by the formation of gp100-specific antibodies.
编码肿瘤特异性抗原的DNA代表了潜在的免疫刺激剂。然而，给药过程中DNA的快速酶促降解和片段化会导致载体表达受限，从而疗效不佳。这些挑战使得必须采用新型的DNA递送策略。在此，我们研究了阳离子自组装肽水凝胶包裹质粒DNA并增强其体内免疫刺激潜力的能力。使用三种在形式电荷上有系统差异的凝胶形成肽评估了网络电荷对凝胶保留DNA能力的影响。肽HLT2在中性pH下形式电荷为+5，在包裹微克量的DNA方面表现最佳，对其流变学性质影响很小，使其能够在体内有效通过注射器递送。包裹在这些凝胶中的质粒DNA(TA)编码与警报蛋白佐剂HMGN1融合的黑色素瘤特异性gp100抗原。将负载DNA(TA)的HLT2凝胶植入小鼠体内会引发急性炎症反应，出现多形核细胞，随后有浸润的巨噬细胞。这些细胞浸润有助于处理包裹的DNA，促进淋巴细胞增殖增加，并产生由表达CD4+/IFNγ+的Th1细胞介导的增强免疫反应，并通过形成gp100特异性抗体得到补充。
