Giannini Margherita, Rovito Daniela, Oulad-Abdelghani Mustapha, Messaddeq Nadia, Debrut Léa, Quiring Giulia, Kessler Pascal, Charles Anne-Laure, Geny Bernard, Metzger Daniel, Laverny Gilles, Meyer Alain
Physiology and Muscle function explorations, University hospital of Strasbourg, Strasbourg, France
UR3072 "mitochondrie, stress oxydant et plasticité musculaire", Centre de recherche en biomédecine, Strasbourg, France.
RMD Open. 2025 Mar 5;11(1):e004558. doi: 10.1136/rmdopen-2024-004558.
Inflammatory myopathies (IM) are a group of severe autoimmune diseases, sharing some similarities, whose cause is unknown and treatment is empirical.While C-protein-induced myositis (CIM), the most currently used mouse model of IM, has removed some roadblocks to understand and improve the treatment of IM, it has only been partially characterised and its generation limited by poor reproducibility. This study aimed at optimising the generation and the characterisation of CIM.
In silico analysis was run to identify the top three specific and immunogenic regions of C-protein. The cognate polypeptides were synthesised and used to immunise C57BL/6N mice. Grip strength, walking ability, serum creatine kinase levels and muscle pathology (histological and electron microscopic features) were assessed. Immune cell proportions and interferon signature in muscles were also determined.
Among the three C-protein polypeptides with the highest immunogenic score, immunisation with the amino acids 965-991 induced the most severe phenotype (experimental myositis (EM)) characterised by 37% decrease in strength, 36% increase in hind base width, 45% increase in serum creatine-kinase level and 80% increase in histological inflammatory score. Optical and electron microscopy revealed mononuclear cell infiltrate, myofibre necrosis, atrophy, major histocompatibility complex-I expression as well as sarcolemmal, sarcomeric and mitochondrial abnormalities. Autoantibodies targeting C-protein, proinflammatory T-lymphocytes, macrophages, and type I and II interferon-stimulated transcripts were detected within the muscle of EM mice.
EM recapitulates the common hallmarks of IM. This costless, high throughput, reproducible and robust model, generated in the most commonly used background for genetically engineered mice, may foster preclinical research in IM.
炎性肌病（IM）是一组严重的自身免疫性疾病，有一些相似之处，病因不明且治疗靠经验。虽然C蛋白诱导性肌炎（CIM）是目前最常用的IM小鼠模型，它消除了一些理解和改善IM治疗的障碍，但它仅得到部分表征，且其生成受重复性差的限制。本研究旨在优化CIM的生成及表征。
进行计算机分析以确定C蛋白的前三个特异性和免疫原性区域。合成同源多肽并用于免疫C57BL/6N小鼠。评估握力、行走能力、血清肌酸激酶水平和肌肉病理学（组织学和电子显微镜特征）。还测定了肌肉中的免疫细胞比例和干扰素特征。
在免疫原性评分最高的三种C蛋白多肽中，用氨基酸965 - 991免疫诱导出最严重的表型（实验性肌炎（EM）），其特征为力量下降37%、后足基部宽度增加36%、血清肌酸激酶水平增加45%以及组织学炎症评分增加80%。光学和电子显微镜显示单核细胞浸润、肌纤维坏死、萎缩、主要组织相容性复合体I表达以及肌膜、肌节和线粒体异常。在EM小鼠的肌肉中检测到靶向C蛋白的自身抗体、促炎性T淋巴细胞、巨噬细胞以及I型和II型干扰素刺激的转录本。
EM概括了IM的常见特征。这个在基因工程小鼠最常用的背景下生成的、无成本、高通量、可重复且稳健的模型，可能会促进IM的临床前研究。
