MSC-Exo(wingor)

中文摘要 间充质干细胞（mesenchymal stem cell，MSC）源性外泌体（MSC derived exosome，MSC-Exo）是由MSC通过旁分泌作用产生的携带大量生物信息传播介质和活性物质的脂质双分子层包裹纳米级囊泡，可实现有选择性、定向性的细胞间信号转导，抑制炎症反应，促进受损组织的修复与再生。此文就MSC-Exo的生物学特性、作用机制及其在常见疾病治疗中的潜在应用与发展进行综述。 正文 干细胞是能够实现自我更新、自主增殖的原始细胞，在体内可分化产生某种特定组织类型的功能细胞。近年来，干细胞引起了研究者的广泛关注，且研究发展迅速，其中被研究最多的为间充质干细胞（mesenchymal stem cell，MSC）。按来源划分，MSC属成体干细胞，来源广泛，可从骨髓、脂肪组织、胎盘、脐带和脐带血等不同组织中获取，能够参与组织器官的修复与再生。 外泌体（exosome，Exo）是非常重要的细胞外囊泡，直径30~100 nm，广泛存在于机体几乎所有细胞及多种体液中。MSC源性Exo（MSC derived Exo，MSC-Exo）携带大量生物信息传播介质和活性物质，可实现选择性、定向性细胞间信号转导，抑制炎症反应，促进受损组织的修复与再生。本文就MSC-Exo的生物学特性、作用机制及其在常见多发疾病中的研究进展进行综述，以期为MSC-Exo在各种难治疾病中的规范有序应用提供借鉴。 1 MSC-Exo的生物学特性与作用机制 MSC-Exo是由磷脂双分子层包被且腔内充满多种蛋白质、核酸、脂质和可溶性因子的纳米级囊泡，通过细胞膜内陷方式从MSC中释放。如图1所示，MSC-Exo的特殊“脂筏”结构使其表面含有特异蛋白（如CD9、CD63、CD81等），能够直接与靶细胞的质膜融合，还可通过细胞内吞实现信息传递，参与信号转导、炎症因子释放调控、细胞增殖分化调控等过程。 相较于MSC，无细胞结构的MSC-Exo易于存储管理，且稳定性更好、免疫原性更低，可有效减少医源性肿瘤的形成和生长，进而降低细胞治疗过程中存在的风险。研究者认为，MSC-Exo可成为替代MSC的无细胞治疗新手段并具有光明前景，目前已在恶性肿瘤、肝脏疾病、心血管及神经退行性疾病、糖尿病等常见疾病的动物模型中对其进行了广泛探究。 MSC-Exo主要通过与靶细胞进行融合，向靶细胞释放神经因子、微RNA（microRNA，miRNA或miR）及多种蛋白质等活性物质，或直接与靶细胞的表面受体结合进行基因调控以发挥其免疫调节和促进组织再生和修复的作用。然而MSC-Exo在不同疾病中的作用机制复杂，更为具体的调控机制仍是研究者攻克的难点。 2 MSC-Exo在常见疾病中的研究进展 2.1 恶性肿瘤 MSC-Exo可通过释放活性物质参与调控肿瘤细胞的血管生成能力和上皮间质转化过程，同时在大多肿瘤细胞内可实现自由扩散和定植，对肿瘤微环境产生一定影响，进而实现对肿瘤细胞生物学功能的调节。 肝细胞癌（hepatocellular carcinoma，HCC）即肝癌，是常见的恶性肿瘤，死亡率居全球第4位。研究显示，MSC-Exo可通过不同机制保护肝脏，抑制HCC的发展、转移和耐药。Ding等发现，由骨髓源的MSC-Exo——BMSC-Exo转移的miR-374c-5p对HCC患者的细胞增殖和转移具有抑制作用。Lou等证明，源于脂肪组织的MSC-Exo可通过携带miRNA-199a调节哺乳动物雷帕霉素靶蛋白信号通路，进而提高HCC的化学治疗敏感性。此外，研究显示，MSC-Exo也可作为载体靶向递送抗肝癌物质（药物或基因），以实现疾病治疗。Li等利用葡萄糖调节蛋白78特异性干扰小RNA修饰的BMSC-Exo联合索拉非尼后，能够靶向HCC细胞中的葡萄糖调节蛋白78，使耐药肿瘤细胞对索拉非尼增敏，逆转耐药性，提高疗效。 结肠癌在我国的发病率逐年升高。研究显示，除手术切除和常规用药外，携带miRNA的MSC-Exo被认为是新型的生物标志物，可用于结肠癌的诊断和预测。李晓辉等证实了高表达miR-196b-5p的MSC-Exo可降低结肠癌CT26.WT细胞对5-氟尿嘧啶的耐受性，从而促进细胞凋亡。其作用的潜在机制被认为与抑制PI3K/Akt信号通路的激活有关。Chen等研究发现，BMSC-Exos中miR-4461可以通过下调包被体蛋白复合物亚基β的表达，进一步抑制结直肠癌细胞HCT116和SW480的细胞迁移和侵袭，是潜在的结肠癌治疗靶点。 胃癌早期通常无症状，这是导致患者因确诊延时而错过最佳手术时机的最主要因素，进而造成多数胃癌发现即晚期的现象；虽然可采取手术联合用药的策略进行治疗，但预后效果仍不理想。杜雄等研究发现，在缺氧条件下，BMSC-Exo能够促进Wnt/β联蛋白信号通路的激活，实现胃癌细胞的快速增长和转移。同时，董俊刚等研究发现，胃癌细胞的生长和转移与BMSC-Exo的分泌呈正相关，即BMSC-Exo促进胃癌细胞的增殖。这为研究靶向BMSC- Exo治疗胃癌奠定了理论基础。 近年来，肺癌患者的新增率和死亡率均居高不下。非小细胞肺癌（non-small cell lung cancer，NSCLC）作为肺癌的一大种类，传统治疗手段为手术切除和药物治疗，治疗效果不理想。MSC-Exo作为远程信号效应物，可远距离进行细胞间信息交流，进而调控肿瘤的生物学功能、生长状态和耐药性等。Liang等阐述了BMSC-Exo中的miR-144通过下调细胞周期蛋白E1和E2从而抑制NSCLC细胞的增殖，以此间接阻断肿瘤生长。 乳腺癌是世界范围内女性群体高发的浸润性恶性肿瘤，如今除常规化学治疗和手术切除外，MSC-Exo也可作为载体联合化学药物对其进行治疗。如BMSC-Exo装载阿霉素（doxorubicin，DOX）是目前研究较为集中的一个载药系统，实验表明，BMSC-Exo@DOX的药物载体可靶向结合乳腺癌细胞，同时不会削弱和降低药物本身对癌细胞的杀伤作用。MSC-Exo装载和厚朴酚（Honokiol）也是重要的载药系统，Kanchanapally等将乳腺癌细胞系与Honokiol、MSC-Exo@Honokiol共培养72 h后发现，MSC-Exo@Honokiol组对癌细胞的杀伤力远高于Honokiol组，是Honokiol组的4~5倍，潜在机制是缩短细胞周期和加快细胞凋亡从而遏制癌细胞的生长。 MSC-Exo在其他肿瘤治疗中的应用也有所报道，如通过对肾癌细胞内胆固醇代谢关键酶的表达量进行调控，进而影响肾癌细胞的生物学功能和行为；高浓度MSC-Exo可抑制口腔鳞状细胞癌的生长，这可能是由于MSC-Exo结合PI3K/Akt信号通路靶点，通过直接或间接接触的方式抑制癌细胞增长和定植；MSC-Exo作为旁分泌的一种重要活性物质，可通过向前列腺癌细胞递送miR-126-3p进而遏抑癌细胞的增殖和迁移。 2.2 肝脏疾病 肝功能受损导致肝细胞的自我调节与再生功能异常，从而诱发各种肝脏疾病，如肝硬化、肝炎等。目前，肝移植仍是治疗肝脏疾病的主流治疗措施，但供体器官短缺及移植后产生的终身免疫等问题阻碍了肝移植技术的发展。随着MSC-Exo的发现，肝脏疾病治疗有了新的方向。国内外均有开展利用MSC-Exo治疗肝脏疾病的实验研究（表1）。 Watanabe等用非酒精性脂肪性肝炎（non-alcoholic steatohepatiti，NASH）模型评估MSC-Exo的治疗效果发现，MSC-Exo可减轻NASH的炎症反应并抑制纤维化。宋晓静分别构建大鼠肝切除模型及大鼠缺血再灌注损伤模型，并进行体内注射人脐带来源的MSC-Exo（human umbilical MSC-Exo，hUCMSC- Exo），验证了其发挥促进肝再生、减轻肝脏缺血再灌注损伤的作用。急性肝衰竭（acute liver failure，ALF）也是一种常见的肝脏疾病，Wu等利用C57BL/6小鼠和LO2细胞ALF模型，进一步探究hUCMSC-Exo的治疗机制，结果证明其可通过上调胞外信号调节激酶（extracellular signal-regulated kinase，ERK）1/2和PI3K/Akt信号通路，抑制氧化应激诱导的细胞凋亡，减少氧化应激，从而达到保护肝脏的目的。除此之外，hUCMSC-Exo也被证实可以延缓和减轻小鼠模型的肝损伤程度。 Psaraki等通过建立的急性肝病或慢性肝病动物模型，确定了不同来源的MSC-Exo可有效发挥抗凋亡、抗炎和抗纤维化等作用，同时证明了MSC-Exo的靶向能力可通过膜修饰来提高。这意味着MSC-Exo的修饰可能是肝病治疗的有前途的替代方法。除直接注射进行治疗外，有研究人员利用MSC-Exo设计药物递送系统，用于装载激素药物地塞米松（dexamethasone，DEX），即构建装载有地塞米松的MSC-Exo@DEX。该载药系统可降低肝脏转氨酶和炎症因子的表达水平，进而有效减小激素药物对肝脏的损伤。这也给肝脏疾病的无细胞治疗和药物递送载体的构建提供了新的思路。 2.3 心血管及中枢神经系统疾病 近年来，全球范围内的心血管疾病（cardiovascular disease，CVD）和中枢神经系统疾病（central nervous system disease，CNSD）发病率均呈上升趋势。通常CVD和CNSD被认为是不可逆的损伤，目前的治疗手段仍存在一定的局限性。已有大量研究证实，MSC-Exo在CVD和CNSD相关疾病模型中具有极大的治疗潜力。 CVD在我国是常见高发疾病，同时具有全球高发病率和高病死率。研究发现，体内和体外进行MSC-Exo移植均可通过增强血管生成能力、减轻心脏纤维化，达到修复损伤心肌细胞和保持心脏功能的目的。Zhao等发现，MSC-Exo可通过miR-182信号通路改变M1巨噬细胞向M2巨噬细胞的极化来减轻心肌I/R损伤，为MSC-Exo作为心肌I/R损伤的潜在治疗工具提供了新的思路。Liu等探索了过表达巨噬细胞移动抑制因子的BMSC-Exo的外显子在心肌梗死大鼠模型中的心脏保护作用。结果发现，其可通过减少心脏重塑及心肌细胞线粒体断裂，避免活性氧生成和细胞凋亡，进而实现心脏功能的增强。该研究阐述了以巨噬细胞移动抑制因子-MSC-Exo为基础的心肌梗死治疗的新机制，并为心血管疾病的诊治提供了崭新的方式。 CNSD主要包括阿尔茨海默病（Alzheimer disease，AD）、帕金森病（Parkinson disease，PD）、脊髓损伤(spinal cord injury，SCI) 等，其特点是神经元结构和功能丧失，进而阻碍神经元间的信息转导。MSC-Exo内含抗炎RNA和多种神经保护蛋白，可对神经细胞发挥保护作用。Perets等使用以金纳米颗粒作为标记剂的计算机体层成像技术追踪鼻腔内给药的MSC-Exo在不同脑病中的迁移和归巢模式，发现MSC-Exo能够特异性靶向不同病理小鼠模型的大脑区域并进行累积；而在对照组中则呈现弥漫性迁移模式，这和神经免疫应答的趋化能力存在紧密联系。黄荣等对AD小鼠模型进行静脉输注BMSC-Exo，连续给药21 d后发现，与未处理组相比，BMSC-Exo组小鼠逃避潜伏期显著缩短，Toll样受体2、诱生型一氧化氮合酶及含NACHT、LRR和PYD结构域蛋白3等因子表达显著减少，三结构域蛋白31的表达显著增加。这意味着BMSC-Exo可能通过促进三结构域蛋白31表达和抑制炎症小体的产生来改善AD小鼠的认知功能障碍。另有研究表明，在SCI模型大鼠中，接受注射MSC-Exo组别的病变处神经和血管内皮的细胞数量均有所增加，表现出良好的神经及血管再生能力。Yang等利用MSC-Exo包被反义寡核苷酸4（Exo-ASO4）进行药物递送，结果表明 Exo-ASO4可到达PD模型小鼠的脑实质并明显降低α突触核蛋白的表达量进而减弱其在病灶内的聚集程度，减轻PD模型小鼠的多巴胺神经元退化，改善运动功能障碍。 2.4 炎症类疾病 炎症反应是指当机体受到病原微生物感染、创伤、变态反应等刺激时，自身产生一系列组织细胞的反应。通过MSC标志物（如CD29、CD44、CD90和CD73）标记发现，MSC-Exo可驻留在受伤和发炎的组织中，将活性物质转移至受体细胞，从而介导细胞间通讯，改变受体细胞的基因表达并影响其生理和病理状态。MSC-Exo可通过对免疫细胞和炎症细胞的极化反应进行调控，达到减轻炎症反应、抑制氧化应激和修复的目的，具体机制如表2所示。 MSC-Exo治疗的炎症类疾病主要涉及骨科疾病、泌尿系统疾病、免疫系统疾病、消化系统疾病以及呼吸系统疾病等5大类。 骨科相关炎症疾病中最为常见的是骨关节炎（osteroarthritis，OA），以关节软骨病变为主。已有研究表明，MSC-Exo促进软骨损伤修复的重要作用机制之一是抑制炎症因子表达，从而为软骨修复提供良好的微环境。Zhou等采用负载miRNA-126-3p的滑膜MSC-Exo处理OA大鼠，处理后的大鼠软骨组织中IL-1β、IL-6和TNF-α的蛋白表达量均降低，进而抑制骨赘形成，防止软骨退变，并对关节软骨发挥抗凋亡和抗炎作用。Jin等在OA大鼠模型的膝关节上进行前交叉韧带横切和内侧半月板-胫骨韧带切除手术，然后在关节内注射BMSC-Exo，发现其能减轻大鼠模型的软骨破坏程度、促进软骨下骨重塑。结果说明BMSC-Exo通过减少软骨细胞的衰老和凋亡对OA起到治疗作用，这表明BMSC-Exo可能为OA治疗提供候选治疗方法。 膀胱炎和肾脏疾病均是常见的泌尿系统疾病。Wen等建立了动物模型发现，MSC-Exo可减轻胶原纤维累积并促进组织再生，从而保护组织免受损伤，有助于治疗间质性膀胱炎/膀胱疼痛综合征且无致瘤性。Lu等发现BMSC-Exo可通过激活前列腺素E2受体2遏抑促炎因子分泌，改善M1和M2型细胞的极化状态，减少肌成纤维细胞的形成，进而降低细胞外基质沉积和肾纤维化的程度。 常见的免疫系统疾病包括类风湿关节炎（rheumatoid arthritis，RA）和系统性红斑狼疮（systemic lupus erythematosus，SLE）等。目前临床应用较多的RA治疗药物为生物制剂和小分子激酶抑制剂，但药物自身的毒性极大限制了RA的治疗效果。赵相卓等利用 BMSC-Exo对RA-成纤维型滑膜细胞模型进行处理，结果证明，BMSC-Exo可通过抑制p38丝裂原激活的蛋白激酶活化进而抑制RA-成纤维型滑膜细胞的生长和转移，减少炎症因子分泌。王喆等通过构建负载双氯芬酸钠（diclofenac sodium，DS）的MSC-Exo（DS@EX），利用激光共聚焦成像观察发现，与普通药物递送载体相比，DS@EX可以更多地累积于发炎的关节中；同时，DS@EX减弱了关节表面的骨侵蚀，其骨密度值由921 mg/cm3升高至1 195 mg/cm3。这表明DS@EX可以减弱RA小鼠的炎性反应并缓解骨质的侵蚀。SLE也是多因素介导的自身免疫疾病。最近的研究证实，在动物模型中，BMSC-Exo可以提高miR-10a-5p的表达，进而靶向下调紫外线抵抗相关基因的表达水平，达到抑制SLE外周血单个核细胞增殖并促进细胞凋亡的目的。 慢性肝炎和炎性肠病（inflammatory bowel disease，IBD）是较为常见的消化系统疾病。自身免疫性肝炎（autoimmune hepatitis，AIH）是一种高发慢性肝炎疾病，MSC-Exo通过特定的miRNA调节肝脏Treg和Th17的比例对AIH起治疗作用。Lu等建立AIH小鼠模型，应用携带miR-223-3p的MSC-Exo进行处理。结果显示，MSC-Exo可通过miR-223-3p调控信号转导及转录激活蛋白3、IL-1β以及IL-6的表达，同时提高Treg/Th17比值，进而减轻肝损伤，利于AIH的炎症修复。IBD是一种非特异性的慢性肠道炎症疾病，分为溃疡性结肠炎（ulcerative colitis，UC）和克罗恩病（Crohn disease，CD）。随着其发病率的逐年上升，目前IBD已成为全球性疾病。通过构建IBD的动物模型发现，MSC-Exo治疗IBD的潜在机制可能是参与调节相关转录因子的表达，进而发挥炎症抑制作用。Pak等应用源于人胎盘（human placenta，hp）的MSC-Exo（hPMSC-Exo）治疗CD具有良好的安全性和治疗效果。Duan等采用三硝基苯磺酸诱导构建UC小鼠模型，并采用原位注射hPMSC-Exo的方式进行治疗。结果显示，注射hPMSC-Exo可调节结肠细胞中促炎和抗炎细胞因子的平衡；同时，hPMSC-Exo还可通过降低髓过氧化物酶MPO和活性氧类的活性来抑制氧化应激。 常见的呼吸系统疾病包括哮喘、急性呼吸窘迫综合征（acute respiratory distress syndrome，ARDS）和COVID-19等。因为过敏性鼻炎是导致哮喘病发的主要因素之一，所以治疗过敏性鼻炎也是从根本上治疗哮喘的有效途径。吴杰应用低氧处理的hUCMSC-Exo治疗过敏性鼻炎小鼠模型，结果发现，实验小鼠的IL-4和IL-10的表达量明显下降，存在更低分化程度的树突状细胞，进而证明MSC-Exo的注入可以增强对过敏性鼻炎的疗效。ARDS属于弥漫性肺损伤，是全球性普发疾病。胡松采用ARDS小鼠模型，通过尾静脉注入BMSC-Exo观察发现，实验组小鼠的生存率得到提高，同时肺组织炎症得到缓解。COVID-19具有高传播性和强变异性的特点，目前尚无有效治疗方法。MSC-Exo对病灶的免疫调节和组织修复能力可视作 COVID-19创新性疗法的重要基础，具有强大的医治潜力。Sengupta等在患有ARDS的COVID-19受试者中进行了第1阶段临床试验，结果显示，采用BMSC-Exo治疗的患者肺部的血氧饱和度以及氧合指数均显著升高，且体内炎症因子水平降低，患者存活率高达83%，肺部损伤情况也有所改善。 2.5 骨科疾病 骨骼是人体重要的器官，参与运动系统的组成，同时发挥支持和保护作用。骨科疾病除上述炎症疾病外，常见疾病还包括软骨损伤、骨折和骨质疏松（osteoporosis，OP）等。 MSC-Exo可促进软骨细胞增殖和基质生成，维持微环境“稳态”，还可激活软骨的修复和再生能力。Zhang等利用大鼠模型证实BMSC-Exo通过调控CD73的表达参与PI3K/Akt和ERK信号传导过程，进而促进细胞快速生长和浸润，实现软骨修复。此外，MSC-Exo携带的遗传分子也可以促进软骨修复。王宪峰等构建稳定过表达LncRNA H19的MSC并提取外泌体（H19-Exo），将其用于大鼠骨关节炎模型的治疗，证实高表达LncRNA H19的MSC-Exo通过靶向miR-29b-3p/转化生长因子β1/Smad3通路，促进软骨细胞的增长与再生，修复软骨损伤。 骨折修复是包括血管生成、细胞分化、成软骨合成的再生过程，愈合延迟或不愈合的现象会导致患者需要反复治疗，严重影响患者的生活质量。研究证实，促使MSC对骨骼组织进行再生修复的重要物质之一就是MSC-Exo。李畅等发现BMSC-Exo可以促进愈伤组织中骨形态发生蛋白2、Smad1和Runt相关转录因子2的表达，同时在骨折大鼠模型中，用BMSC-Exo治疗的组别愈伤组织体积明显增大，骨体积分数也显著提高。这表明BMSC-Exo可有效增强成骨作用。Furuta等通过尾静脉输注方式将MSC-Exo分别用于愈合能力障碍的CD9型小鼠和野生型小鼠。结果发现，MSC-Exo在成骨细胞内富集并积累，进而促进成骨细胞的增长，并极大缩减骨修复时间。 OP是常见、多发的骨代谢疾病，主要病征包括骨密度下降和骨组织微结构损伤。研究发现，MSC-Exo可通过介导骨代谢相关信号通路而实现对相关疾病的治疗。田荣华的研究显示，hUCMSC-Exo能促进骨质疏松大鼠成骨细胞的增殖，并呈浓度依赖性。其主要通过hUCMSC-Exo调控骨代谢循环，促进血管生成和成骨转化实现，进而对OP大鼠模型发挥修复作用。研究发现，MSC-Exo富含的多种microRNA能恢复继发性损伤，促进神经元细胞的修复和再生。张美玲等研究发现，注射MSC-Exo的大鼠模型组比注射PBS组的神经元光密度更高，而且信号转导及转录激活蛋白3与生长相关蛋白43的表达量更多，表明MSC-Exo可通过调控该通路促进轴突生长，进而发挥对神经元细胞的修复和再生作用，最终改善损伤大鼠的感觉功能。 2.6 其他疾病 除上述代表性疾病外，MSC-Exo的应用研究还有很多，如可用于创面愈合。皮肤通过对机体形成保护屏障以避免外界有害物质进入体内，当皮肤组织遭受外伤或糖尿病带来的并发症时，皮肤组织会产生不同程度的创伤。研究发现，MSC-Exo可控制胶原纤维在伤口愈合中的分布，减少瘢痕形成的同时加快创面愈合。此外，MSC-Exo包含的miRNA参与调控转化生长因子β信号通路，可诱导肌成纤维细胞分化，同时抑制促炎因子分泌，促进抗炎因子表达，利于创伤修复。 MSC-Exo在糖尿病及其并发症中同样发挥作用，Hu等发现经吡格列酮预处理后的MSC-Exo在高糖环境中可通过调控PI3K/Akt/内皮型一氧化氮合酶信号通路进而增强血管再生能力，促进糖尿病足溃疡的创口愈合。还有研究证实，MSC-Exo中的miR-17-5p可激活PTEN/Akt/低氧诱导因子1/血管内皮生长因子信号通路，提高血管内皮生长因子的表达水平进而加快血管生成，修复糖尿病产生的慢性伤口。 除此之外，MSC-Exo还可用于子宫内膜损伤和卵巢相关疾病。Zhang等构建子宫腔粘连（intrauterine adhesion，IUA）模型动物以评估MSC-Exo对IUA的治疗效果。结果发现， MSC-Exo能够阻遏TGF-β-Smad信号通路的转录与表达，促进血管生成，从而逆转子宫内膜纤维化。杜小倩等采用卵巢早衰（premature ovarian failure，POF）大鼠模型腹腔注射hUCMSC-Exo，结果发现，hUCMSC-Exo可依靠改善POF小鼠的3种激素水平来修复大鼠卵巢功能，为POF的无细胞疗法奠定实验基础。 3 展望 MSC-Exo通过MSC旁分泌途径作用于靶细胞，释放内容物将信息传递给靶细胞，调控细胞生物学行为。而其无细胞的“脂筏”结构更赋予了MSC-Exo更高的信息转导效率、稳定性和安全性，同时也更利于储存，这显示出无细胞疗法的巨大发展潜能。目前大量基础研究已证实MSC-Exo能够减轻炎症反应，实现细胞损伤的修复与再生，同时可作为药物载体进行联合治疗，提高药物局部浓度进而增强疗效。而且经过修饰的MSC-Exo载药系统具备更高的靶向能力和更好的生物相容性。因而通过开发设计MSC-Exo载药系统以及对MSC-Exo进行靶向修饰来提高治疗精准性均具有广阔的应用前景。 从Clinicaltrials披露的研究数据可以发现，当前采用无细胞疗法治疗疾病的临床研究仍是空白，缺乏相关的临床试验，MSC-Exo对于各种疾病的治疗研究多处于动物模型试验阶段。这意味着MSC-Exo还未达到商业化制备的条件，相关高效、标准化的制备方法亟待探究，同时缺少合理化、规范化的临床应用标准。选择合适的剂量和最佳给药途径，也是推进MSC-Exo临床治疗应用的难点之一。此外，MSC-Exo在不同疾病治疗中的相关分子机制尚未阐述清晰，治疗过程中的药代动力学和不良反应等问题仍未被解答，未来仍需对MSC-Exo展开深入探索，以便评估其在无细胞疗法中的价值。 作者 孙馨  黄玉香 青岛奥克生物开发有限公司研发部，青岛 266000 通信作者：黄玉香， Email：abmd2003@163.com 引用本文：孙馨, 黄玉香. 间充质干细胞源性外泌体在疾病治疗中的潜在应用研究进展 [J]. 国际生物制品学杂志, 2024, 47(4): 260-268.   DOI: 10.3760/cma.j.cn311962-20231115-00018 识别微信二维码，添加生物制品圈小编，符合条件者即可加入 生物制品微信群！ 请注明：姓名+研究方向！ 版 权 声 明 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BrainStorm to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) for NurOwn® for the treatment of ALS New clinical analyses reinforce the conclusions from NurOwn's® Phase 3 clinical trial Conference call and webcast at 8:00 a.m. Eastern Time today NEW YORK, Aug. 15, 2022 /PRNewswire/ -- BrainStorm Cell Therapeutics Inc. (NASDAQ: BCLI), a leading developer of adult stem cell therapeutics for neurodegenerative diseases, today announced financial results for the second quarter ended June 30, 2022, and provided a corporate update. The company also announced its decision to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration for NurOwn® for the treatment of amyotrophic lateral sclerosis (ALS). BrainStorm announces decision to submit a BLA to the FDA for NurOwn® for the treatment of ALS "Brainstorm Cell Therapeutics is at a pivotal moment as a company as we finalize the regulatory filing for NurOwn® in the treatment of ALS. The continued analysis and the feedback received from the many scientific presentations of NurOwn's® Phase 3 data have uncovered key insights that furthered our understanding of the product mechanism of action and therapeutic potential and strengthened the conclusions of NurOwn's® efficacy," said Chaim Lebovits, Chief Executive Officer. "After carefully considering these learnings, the totality of the evidence from NurOwn's® clinical studies, and the feedback received from key opinion leaders and the broader ALS community, we will submit a Biologics License Application to the FDA. We are deeply grateful to the ALS clinical experts, members of the ALS community and faithful investors for their contribution to the development of NurOwn® and what it may mean to those living with ALS. Their contributions and commitment made our current progress possible and continue to inspire us as we prepare for the considerable work ahead. We intend to provide additional updates upon learning whether the FDA files our BLA submission." New clinical analyses strengthen the conclusions from NurOwn's® Phase 3 clinical trial A correction was made to the Muscle and Nerve publication from December 2021 describing the results of NurOwn's® Phase 3 clinical trial in ALS following new clinical analyses which strengthen the Company's original conclusions from the trial. The correction results in a statistically significant treatment difference (p=0.050) of more than 2 points for an important secondary endpoint, average change from baseline in ALSFRS-R, in the pre-specified efficacy subgroup of participants with a baseline score of at least 35. Analyses reported in the original publication utilized an efficacy model that unintentionally deviated from the trial's pre-specified statistical analysis plan by erroneously incorporating interaction terms between the subgroup and treatment. The newly published results, which includes supporting information to the publication, employ the efficacy model as pre-specified in the trial's statistical analysis plan, correcting the analyses. The correction also relates to the other subgroup analyses published for this endpoint, demonstrating that all subgroups with ALSFRS-R baseline scores of at least 26 to 35 showed a statistically significant benefit following treatment with NurOwn® (p≤0.050) on this secondary endpoint. Other Second Quarter 2022 and Recent Highlights Presented new analyses from NurOwn's® Phase 3 ALS trial that showed a treatment effect in participants predicted by the ENCALS model to have intermediate to very long survival. These analyses confirmed the importance of avoiding potentially misclassifying treatment responses due to the ALSFRS-R floor effect and were presented in a poster presentation at the 2022 European Network for the Cure of ALS (ENCALS) Meeting. The presentation was delivered by Dr. Jonathan Katz, principal investigator on the trial and Chair of the Neurology Department and Director of the Forbes Norris ALS Clinic at the California Pacific Medical Center. Biomarker analyses from NurOwn's® Phase 3 ALS trial were the subject of an abstract presented at the 2022 American Academy of Neurology Congress by Dr. James Berry, MD, MPH, principal investigator on the trial and Director of the Massachusetts General Hospital Multidisciplinary ALS Clinic and Chief of the Division of ALS and Motor Neuron Diseases. Results of the analyses showed significant changes across multiple cerebrospinal fluid (CSF) biomarkers following NurOwn® treatment, with the strongest effects observed on biomarkers related to neuroprotection and neuroinflammation. Presented a summary of analyses from the Phase 3 trial of NurOwn® in ALS that highlighted the ability of biomarkers to predict clinical treatment response and provide a window into the complex biological pathways underlying disease progression. The presentation was delivered at the ALS Drug Development Summit by BrainStorm's President and Chief Medical Officer, Dr. Ralph Kern, MD, MHSc. Reported new results from the open-label Phase 2 study of NurOwn® in progressive multiple sclerosis (MS) that highlighted post-treatment improvements in monocular and binocular low contrast letter acuity (LCLA) outcomes (1.25% and 2.5% thresholds). In contrast, matched patients from the long-term Comprehensive Longitudinal Investigation of Multiple Sclerosis (CLIMB) study and participants from the placebo arm of the SPRINT study showed worsening in LCLA outcomes over a similar time period. The results were presented in a poster presentation delivered by Dr. Kern at the 2022 Consortium of Multiple Sclerosis Centers (CMSC) Meeting. Presented biomarker analyses from the open-label Phase 2 study of NurOwn® in progressive MS showing consistent post-treatment reductions in CSF inflammatory biomarkers that may be relevant to disease progression and treatment response. The presentation was delivered by Dr. Christopher Lock, PhD, Clinical Associate Professor, Neurology and Neurological Studies, at Stanford School of Medicine, at the CMSC 2022 Meeting. Preclinical in-vitro data that showed NurOwn® cells maintaining their neurotrophic and immunomodulatory effects in the presence of Siponimod, an S1P modulator recently approved for the treatment of secondary progressive MS, were presented in a poster presentation at the CMSC 2022 Meeting. The presentation was delivered by Dr. Sidney Spector, MD, PhD, Senior Vice President, Medical Affairs and Global Strategy at BrainStorm Cell Therapeutics. Reported preclinical data from a murine lung injury model (the bleomycin model) that demonstrated intrathecal administration of NurOwn®-derived exosomes (Exo MSC-NTF) may have potential as a clinical therapy for inflammatory pulmonary pathologies and display superior macrophage immunomodulation compared to naïve mesenchymal stem cell-derived exosomes (Exo-MSC). The data were presented at the International Society for Extracellular Vesicles (ISEV) 2022 Annual Meeting by Haggai Kaspi, PhD, Preclinical Research Manager at BrainStorm Cell Therapeutics. Preclinical in vitro data demonstrating the superior anti-inflammatory effects of Exo MSC-NTF compared to Exo-MSC were featured in a poster at the International Society of Cell & Gene Therapy (ISCT) 2022 Meeting. The poster was presented by Dr. Kim Thacker, Senior Vice President, Medical Affairs and Clinical Innovation at BrainStorm Cell Therapeutics. Strengthened executive team in preparation for anticipated growth and corporate development, with the appointment of Netta Blondheim-Shraga, PhD, as VP of Research & Development and Antal Pearl-Lendner, Adv., as Chief Legal Counsel Financial Results for the Second Quarter Ended June 30, 2022 Cash, cash equivalents, and short-term bank deposits were approximately $12.2 million as of June 30, 2022, compared to $18.4 million as of March 31, 2022. Research and development expenses for the three months ended June 30, 2022, and 2021 were approximately $5.1 million and $3.6 million, respectively. General and administrative expenses for the three months ended June 30, 2022, and 2021 were approximately $2.5 million. Net loss for the three months ended June 30, 2022, was approximately $7.0 million, as compared to a net loss of approximately $6.3 million for the three months ended June 30, 2021. Net loss per share for the three months ended June 30, 2022, and 2021 was $0.19 and $0.17, respectively. Conference Call and Webcast August 15, 2022, at 8:00 a.m. Eastern Time Participant Numbers: Toll Free: 888-506-0062 International: 973-528-0011 Participant Access Code: 955552 Webcast URL: Those that wish to listen to the replay of the conference call can do so by dialing the numbers below. The replay will be available for 14 days. Toll Free: 877-481-4010 International: 919-882-2331 Replay Passcode: 46290 About NurOwn® The NurOwn® technology platform (autologous MSC-NTF cells) represents a promising investigational therapeutic approach to targeting disease pathways important in neurodegenerative disorders. MSC-NTF cells are produced from autologous, bone marrow-derived mesenchymal stem cells (MSCs) that have been expanded and differentiated ex vivo. MSCs are converted into MSC-NTF cells by growing them under patented conditions that induce the cells to secrete high levels of neurotrophic factors (NTFs). Autologous MSC-NTF cells are designed to effectively deliver multiple NTFs and immunomodulatory cytokines directly to the site of damage to elicit a desired biological effect and ultimately slow or stabilize disease progression. About BrainStorm Cell Therapeutics Inc. BrainStorm Cell Therapeutics Inc. is a leading developer of innovative autologous adult stem cell therapeutics for debilitating neurodegenerative diseases. The Company holds the rights to clinical development and commercialization of the NurOwn® technology platform used to produce autologous MSC-NTF cells through an exclusive, worldwide licensing agreement. Autologous MSC-NTF cells have received Orphan Drug designation status from the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of amyotrophic lateral sclerosis (ALS). BrainStorm has completed a Phase 3 pivotal trial in ALS (NCT03280056); this trial investigated the safety and efficacy of repeat-administration of autologous MSC-NTF cells and was supported by a grant from the California Institute for Regenerative Medicine (CIRM CLIN2-0989). BrainStorm completed under an investigational new drug application a Phase 2 open-label multicenter trial (NCT03799718) of autologous MSC-NTF cells in progressive multiple sclerosis (MS) and was supported by a grant from the National MS Society (NMSS). Safe-Harbor Statement Statements in this announcement other than historical data and information, including statements regarding future BLA submission, constitute "forward-looking statements" and involve risks and uncertainties that could cause BrainStorm Cell Therapeutics Inc.'s actual results to differ materially from those stated or implied by such forward-looking statements. Terms and phrases such as "may," "should," "would," "could," "will," "expect," "likely," "believe," "plan," "estimate," "predict," "potential," and similar terms and phrases are intended to identify these forward-looking statements. The potential risks and uncertainties include, without limitation, BrainStorm's need to raise additional capital, BrainStorm's ability to continue as a going concern, BrainStorm's plan to submit a BLA for NurOwn® to the FDA, prospects that the FDA will accept BrainStorm's BLA for NurOwn® for filing and review, prospects that the FDA does not view BrainStorm's NurOwn® product candidate to have demonstrated adequate safety or effectiveness, prospects for future regulatory approval of BrainStorm's NurOwn® treatment candidate, the success of BrainStorm's product development programs and research, regulatory and personnel issues, development of a global market for BrainStorm's products, if approved, and services, the ability to secure and maintain research institutions to conduct BrainStorm's clinical trials, the ability to generate significant revenue, the ability of BrainStorm's NurOwn® treatment candidate to achieve broad acceptance as a treatment option for ALS or other neurodegenerative diseases, BrainStorm's ability to manufacture and commercialize the NurOwn® treatment candidate, obtaining patents that provide meaningful protection, competition and market developments, BrainStorm's ability to protect our intellectual property from infringement by third parties, health reform legislation, demand for our services, currency exchange rates and product liability claims and litigation; the impacts of the COVID-19 pandemic and additional strains of COVID-19 or any other health epidemic on our clinical trials, supply chain, and operations; potential delays in any planned or anticipated review or interactions with the FDA due to disruptions at, or inadequate funding of, the FDA; the impact of global economic and political developments on our business, including rising inflation and capital market disruptions; the current conflict in Ukraine, economic sanctions and economic slowdowns or recessions that may result from such development; and other factors detailed in BrainStorm's annual report on Form 10-K and quarterly reports on Form 10-Q available at . These factors should be considered carefully, and readers should not place undue reliance on BrainStorm's forward-looking statements. The forward-looking statements contained in this press release are based on the beliefs, expectations, and opinions of management as of the date of this press release. We do not assume any obligation to update forward-looking statements to reflect actual results or assumptions if circumstances or management's beliefs, expectations or opinions should change, unless otherwise required by law. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, levels of activity, performance, or achievements. CONTACTS Investor Relations: John Mullaly LifeSci Advisors, LLC Phone: +1 617-429-3548 [email protected] Media: Lisa Guiterman Phone: +1 202 330-3431 [email protected] The accompanying notes are an integral part of the consolidated financial statements. The accompanying notes are an integral part of the consolidated financial statements. SOURCE BrainStorm Cell Therapeutics Inc