Encapsulated Active Vitamin D Vaccine for the Treatment of Multiple Sclerosis

描述（由申请人提供）：我们提出了一种利用纳米技术开发耐受性原疫苗的转化方法，以大幅减轻多发性硬化症（MS）患者的负担。我们假设，由聚合物醋酸化葡聚糖（Ac-DEX）制成的纳米/微粒包裹了活性形式的维生素D和髓鞘碱性蛋白（MBP），将启动MBP特异性诱导t - regg细胞（iT-regs）的形成，能够以抗原特异性的方式抑制MS。我们的项目是创新的，因为：1)被动体内靶向：以前开发耐受性dc治疗MS的方法需要体外操作。吞噬树突状细胞（DCs）允许被动靶向，因为纳米颗粒太大而不能被非吞噬细胞吸收。被动靶向导致体内的耐受原性药物递送到dc，如活性形式的维生素D（骨化三醇）。目前，骨化三醇在治疗多发性硬化症方面是无效的，因为在改善疾病所需的浓度下，整个组织钙化是突出的。2)。剂量节约：我们的初步研究表明免疫调节剂的包封导致剂量节约。我们假设我们将能够在体内靶向dc并在细胞内递送有效载荷，从而减少所需骨化三醇的量，从而防止组织钙化。靶向的dc会产生耐受性，然后能够诱导形成抑制iT-reg细胞的MS。3)。酸敏感纳米颗粒：酸敏感纳米颗粒暴露在吞噬细胞溶酶体的酸性环境中会降解，释放被包裹的抗原并启动免疫反应。我们之前已经证明，使用我们的pH敏感聚合物Ac-Dex，与游离蛋白和包裹在其他常见聚合物载体中的蛋白质相比，我们可以大幅增加CD4和CD8的呈现。4)。特异性免疫抑制：目前的MS治疗方法需要非特异性全身免疫抑制。我们提出了一种方法，我们可以产生MBP特异性的iT-reg群体，可以抑制MS而不抑制整个免疫系统。我们提供的初步数据显示，地塞米松和MBP肽的包封导致CNS中MBP特异性iT-regs的形成增加，并且在小鼠发生实验性自身免疫性脑脊髓炎（EAE）之前治疗可减少疾病进展。为了开发这些纳米颗粒并测试其功效，我们提出了以下三个具体目标：具体目标1将重点研究骨化三醇和MBP肽在纳米颗粒中的封装。特异性目的2将侧重于评估骨化三醇封装纳米颗粒在体外诱导耐受性DC和iT-regs的作用。特异性目标3将通过MBP和骨化三醇共包被免疫来检测iTregs在体内的形成。最后，通过MS的EAE模型，我们将用我们的纳米颗粒治疗小鼠。如果成功，我们将利用本次资助产生的数据申请R01。此外，我们的纳米颗粒系统可以应用于其他自身免疫性疾病，如1型糖尿病和类风湿性关节炎。

DESCRIPTION (provided by applicant): We present a translational method for developing a tolerogenic vaccine to drastically decrease the burden of patients with multiple sclerosis (MS) by using nanotechnology. We hypothesize that nano/microparticles fabricated from the polymer acetalated dextran (Ac-DEX) that encapsulate the active form of vitamin D, and myelin basic protein (MBP) will initiate the formation of MBP specific inducible T-reg cells (iT-regs) capable of suppressing MS in an antigen specific manner. Our project is innovative because: 1.) Passive in vivo targeting: Previous methods to develop tolerogenic DCs to treatment MS require ex vivo manipulation. Phagocytic dendritic cells (DCs) allow passive targeting since the nanoparticles are too large to be taken up by non-phagocytes. Passive targeting leads to in vivo delivery of tolerogenic agents to the DCs, such as the active form of vitamin D (calcitriol). Currently, calcitriol is ineffective at treating MS because at the concentrations necessary to ameliorate the disease, whole tissue calcification is prominent. 2.) Dose sparing: Our preliminary studies indicate that encapsulation of immunomodulatory agents leads to dose sparing. We hypothesize that we will be able to target DCs in vivo and deliver payload intracellularly, thus decreasing the amount of calcitriol needed, thereby preventing tissue calcification. The targeted DCs will become tolerogenic, which will then be capable of inducing the formation of MS suppressing iT-reg cells. 3.) Acid sensitive nanoparticles: Acid sensitive nanoparticles exposed to the acidic environment of the phagocyte lysosome will degrade, releasing the encapsulated antigen and initiating an immune response. We have previously shown that using our pH sensitive polymer Ac-Dex, we can drastically increase both CD4 and CD8 presentation compared to free protein, and protein encapsulated in other common polymeric carriers. 4.) Specific immune dampening: Current methods of MS treatment require non-specific systemic immune suppression. We present a method in which we can generate a MBP specific iT-reg population that can suppress against MS without suppressing the entire immune system. We present preliminary data that shows encapsulation of dexamethasone and MBP peptide results in increased formation of MBP specific iT-regs in the CNS and reduced disease progression with treatment before experimental autoimmune encephalomyelitis (EAE) onset in mice. In order to develop these nanoparticles and test their efficacy we present the following three specific aims: Specific Aim 1 will focus on calcitriol and MBP peptide encapsulation in nanoparticles. Specific Aim 2 will focus on evaluating calcitriol encapsulated nanoparticles in inducing tolerogenic DC and iT-regs in vitro. Specific Aim 3 will be testing the formation of iTregs in vivo by the immunization with co-encapsulated MBP and calcitriol. Finally, by using the EAE model of MS, we will treat mice with our nanoparticles. If successful, we will take the data generated in this grant and apply for an R01. In addition, our nanoparticle system could be applied to other autoimmune diseases such as Type 1 diabetes and rheumatoid arthritis.