Early Detection and Immunomodulation of PD-1 Inhibitor Induced Cardiotoxicity

PD-1抑制剂心脏毒性的早期检测及免疫调节 摘要 最近发现的免疫检查点抑制剂(ICIS)，特别是PD-1/PD-L1阻滞剂，已经 革命性地治疗晚期恶性肿瘤，包括肺癌、黑色素瘤、头部和 宫颈癌和乳腺癌。ICIS的抗癌作用是由放大的T细胞介导的免疫介导的 回应。然而，ICI治疗会导致不想要的非靶点效应，表现为免疫相关的不良反应。 事件(IrAE)。免疫调节疗法的心脏毒性作用可能是严重的和迅速致命的， 尤其是心肌炎、心力衰竭和心脏性猝死。结果，高达42%的患者出现了 有症状的心血管不良事件死亡。因此，当务之急是：一)发展准确和 用于早期发现这种情况的敏感诊断方法，以及ii)促进我们对 导致ICI相关心脏毒性的机制，以便开发特定的治疗方法。 先前的研究假设，心肌收缩蛋白的片段，肌钙蛋白I(CTnI)，释放 可以触发自身免疫反应，导致irAEs。使用高级 生物信息学工具筛选了超过10万个抗原序列，我们已经确定了一个由13个氨基酸组成的线性 具有极高抗原性指数的cTnI序列(cTnI AA 146-158)。我们还开发了固体- 聚苯乙烯平底中cTnI AA 146-158-亲和素-生物素偶联相表位检测平台 系统。我们的假设是，ICI引起的心脏毒性可以通过心脏MRI及早发现，并且 对心肌细胞来源的cTnI AA14-158抗原的免疫激活可通过以下方法预防 预制抗cTnI AA 146-158中和抗体。为了检验这一假设，我们将执行 以下实验：a)用cTnI AA146-158主要表位免疫正常小鼠形成循环 体内抗cTnI AA 146-158中和抗体，b)在接种的小鼠中应用PD-1抑制剂，以及 生物控制，并比较irAEs的发生率和严重程度。我们将利用高场心脏磁场 具有全面组织定征方案的磁共振成像可客观监测心脏 炎症、纤维化和功能丧失。我们的长期目标是准确地识别线性、构象或 三维空间cTnI表位及新型抗脑梗塞相关心肌治疗药物S的研究 免疫毒性。 意义：如果针对线性cTnI表位(cTnI AA 146-158)的中和疫苗是 在临床前模型中被发现有效地减轻了ICI引起的心肌免疫毒性，这将 促进进一步的翻译研究，具有重要的治疗意义。这一发现将使患者受益 用ICI疗法治疗的侵袭性癌症。早期缺乏新的知识和方法 ICI相关irAEs的检测和治疗调节将减少这些挽救生命的癌症治疗 由于它们的副作用，或导致心脏免疫毒性的高死亡率。

Early Detection and Immunomodulation of PD-1 Inhibitor-Induced Cardiotoxicity Abstract The recent discovery of immune checkpoint inhibitors (ICIs), particularly PD-1/PD-L1 blockers, has revolutionized the management of advanced stage malignancies including lung cancers, melanoma, head and neck, and breast cancers. The anti-cancer effects of ICIs are mediated by amplified T-cell-mediated immune response. However, ICI therapy results in unwanted off-target effects presenting as immune related adverse events (irAEs). Cardiotoxic effects of the immunomodulatory therapies can be serious and rapidly fatal, particularly myocarditis, heart failure and sudden cardiac death. As a result, up to 42% patients presenting with symptomatic cardiovascular adverse events die. Therefore, there is an urgent need to i) develop accurate and sensitive diagnostic modalities for the early detection of this condition, and ii) advance our knowledge on the mechanisms contributing to ICI related cardiotoxicity, so that specific therapies can be developed. Prior studies have postulated that fragments of cardiac contractile protein, troponin I (cTnI), released from the damaged cardiomyocytes could trigger autoimmune response leading to irAEs. Using advanced bioinformatics tools that screened over 100,000 antigenic sequences, we have identified a 13-amino acid linear sequence of cTnI (cTnI AA 146-158) with an exceptionally high antigenic index. We have also developed solid- phase epitope detection platform using cTnI AA 146-158-avidin-biotin conjugation in a polystyrene flat-bottom system. Our hypothesis is that ICI-induced cardiotoxicity can be detected early by cardiac MRI and that the immune activation to cardiomyocyte-derived cTnI AA 14-158 antigens can be prevented by preformed anti-cTnI AA 146-158 neutralizing antibodies. To test this hypothesis, we will perform the following experiments: a) vaccinate normal mice with cTnI AA 146-158 primary epitope to develop circulating anti- cTnI AA 146-158 neutralizing antibodies in vivo, b) administer a PD-1 inhibitor in vaccinated mice and biological controls, and compare the incidence and severity of IrAEs. We will utilize high field cardiac magnetic resonance imaging with comprehensive tissue characterization protocols to objectively monitor cardiac inflammation, fibrosis and loss of function. Our long-term goal is to precisely identify linear, conformational or 3D spatial cTnI epitopes and develop novel therapeutic agent(s) to counteract ICI-associated myocardial immune toxicity. Significance: If the neutralizing vaccine targeted against linear cTnI epitopes (cTnI AA 146-158) is found to be effective to mitigate ICI-induced myocardial immune toxicity in a pre-clinical model, this will facilitate further translational studies with important therapeutic implications. This discovery will benefit patients with aggressive cancers that are treated with ICI-therapy. Lack of new knowledge and approaches for the early detection and therapeutic modulation of ICI-related irAEs will either curtail these life-saving cancer therapies due to their side effects, or lead to high mortality from cardiac immune toxicity.