Recombinant FIV vectors for the delivery of siRNA therapy to joints

描述（由申请人提供）：骨关节炎（OA）是最常见的关节炎形式，也是老年人活动受限和身体残疾的主要原因：65岁以上人群中80%-90%患有OA。OA的现有治疗大多是有限特异性的姑息性治疗。事实上，最近发现的一些口服COX-2选择性抑制剂（如Vioxx， Bextra）的严重副作用强调了开发新型抗炎治疗OA的必要性。本次探索性/发展性R21资助申请的目的是开发一种新颖、简单和高效的方法，用于关节内递送siRNA以治疗关节炎。我们的模型旨在通过非侵入性的一次性应用，显著提高siRNA对关节软硬组织的转导效率，从而在较长时间（几个月）内产生可持续的治疗性siRNA滴度。我们的策略是基于将猫免疫缺陷病毒载体（FIV）的独特特性与靶向关键炎症基因的siRNA的治疗特性相结合。具体来说，我们的实验室已经证明，在单次关节内注射后，VSV-G伪型FIV载体可以成功地用于稳定地转导成年小鼠关节的硬组织和软组织，同时避免引发先天免疫反应。这种直接关节内给药的方法也将治疗效果限制在关节囊内（从而最大限度地减少任何脱靶副作用），在简单、直接的注射后，可以在门诊环境中很容易地进行临床操作，而不需要开放关节手术或其他侵入性手术。我们假设fiv介导的靶向可诱导COX-2和/或mpgs -1基因的siRNA构建物的关节内递送将改善Col1- il1 β (XAT)转基因单关节炎小鼠模型的关节病理、疼痛和功能障碍的发展。我们最初选择关注这些炎症因子，因为环加氧酶途径似乎是关节炎的一个趋同节点，这得到了研究以及非甾体抗炎药物的广泛使用和相对临床成功的支持。基于我们的策略，我们将开发FIV（siRNA）载体，用于将上述siRNA结构转移到患有关节炎的成年小鼠的关节（膝关节和颞下颌关节）。我们评估了这些FIV（siRNA）载体在改善关节病理、疼痛和功能障碍方面的功效，将在成年小鼠关节（膝关节和/或颞下颌关节）关节内注射col1 - il - 1 β (XAT)关节炎模型中进行评估。随着时间的推移，我们将重点评估COX-2和/或mPGES-1的表达，因为它们是FIV（siRNA）治疗的靶标，并评估这种siRNA治疗引发的潜在炎症反应。

DESCRIPTION (provided by applicant): Osteoarthritis (OA) is the most common form of arthritis and a major cause of activity limitation and physical disability in the elderly: 80%-90% of humans over the age of 65 suffer from OA. Available treatments for OA are mostly palliative with limited specificity. In fact, the recently identified serious side effects of some intra- oral COX-2 selective inhibitors (i.e. Vioxx, Bextra) underscore the need for the development of novel anti- inflammatory therapies for OA. The purpose of this Exploratory/Developmental R21 grant application is to develop a novel, simple and highly efficient method for the intra-articular delivery of siRNA to joints for the management of arthritis. Our model aims at significantly improving the transduction efficacy of siRNA to soft and hard tissues of joints via a non-invasive, one-time application that will result in sustainable therapeutic siRNA titers over prolonged periods of time (several months). Our strategy is based on combining the unique properties of the feline immunodeficiency viral vector (FIV) with the therapeutic properties of siRNA targeting key inflammatory genes. Specifically, our laboratory has demonstrated that VSV-G pseudo typed FIV vectors can successfully be used in stably transducing hard and soft tissues of joints in adult mice following a single intra-articular injection while evading the elicitation of an innate immune response. This method of direct intra-articular administration also confines the therapeutic effects within the joint capsule (thus minimizing any off-target side effects) following a simple, straight forward injection that can be readily performed clinically in an ambulatory setting without the need of open joint surgery or other invasive procedure. We hypothesize that FIV-mediated intra-articular delivery of siRNA constructs targeting the inducible COX-2 and/or mPGES-1 genes will ameliorate the development of joint pathology, pain and dysfunction in the Col1- IL1beta(XAT) transgenic mouse model of mono-arthritis. We have initially selected to focus on these inflammatory factors because the cyclooxygenase pathway appears to serve as a node of convergence in arthritis as supported by research studies as well as the extensive use and relative clinical success of non-steroidal anti- inflammatory drugs. Based on our strategy, we will develop FIV(siRNA) vectors for the transfer of the aforementioned siRNA constructs to joints (knee and tempromandibular joint) of adult mice suffering from arthritis. We evaluate the efficacy of these FIV(siRNA) vectors in ameliorating joint pathology, pain and dysfunction will be assessed in the Col1-IL1beta(XAT) arthritis model following intra-articular injection into the joints (knee and/or tempromandibular joint) of adult mice. Emphasis will be given in evaluating COX-2 and/or mPGES-1 expression as they are targets of our FIV(siRNA) therapy over time as well as assessing potential inflammatory responses elicited by this siRNA therapy.