Holtzhausen Christian, Schultheis Dorothea, Berwanger Carolin, Schuld Julia, Schlötzer-Schrehardt Ursula, Riehl-Nestler Marion, Batonnet-Pichon Sabrina, Lilienbaum Alain, Mahabir Esther, van der Ven Peter F M, Fürst Dieter O, Schröder Rolf, Clemen Christoph S
Institute of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany.
Neuropathol Appl Neurobiol. 2025 Oct;51(5):e70038. doi: 10.1111/nan.70038.
The classical morphological hallmarks of the clinically and genetically diverse group of human myofibrillar myopathies are signs of myofibrillar degeneration and desmin-positive protein aggregates. The local sarcomeric enrichment of filamin-C and xin actin-binding repeat-containing proteins 1 and 2 (xirp 1 and xirp 2) is a marker of myofibrillar damage. This work aimed to (i) address filamin-C- and xirp 1/2-positive sarcomeric lesions in desminopathy mouse models, (ii) develop an approach to quantifying xirp 1/2-positive sarcomeric lesions, and (iii) study the effects of acute physical exercise on sarcomeric lesion formation in R349P desmin knock-in mice, which are a model of human R350P desminopathy.
Sarcomeric lesions were visualised by xirp 1/2 and filamin-C immunofluorescence in soleus muscles from R349P and R405W desmin knock-in, desmin knock-out and W2711X filamin-C knock-in mice. The open-source software QuPath was used to analyse xirp 1/2 confocal immunofluorescence images of soleus muscle from nonexercised and treadmill-exercised R349P desmin knock-in mice.
Filamin-C and xirp 1/2 stained muscles revealed the presence of congenerous sarcomeric lesions in heterozygous and homozygous R349P and R405W desmin knock-in, homozygous desmin knock-out and heterozygous and homozygous W2711X filamin-C knock-in mice. Quantitative analysis of R349P desmin knock-in mice showed (i) significantly more lesions in nonexercised heterozygous mice, with an even more pronounced increase in homozygous animals, as compared to wild-type, and (ii) a significant increase in sarcomeric lesions per mm in heterozygous mice and wild-type siblings subjected to strenuous treadmilling.
A QuPath workflow to quantify sarcomeric lesions using xirp 1/2 immunofluorescence images showed augmented densities of lesions in R349P desminopathy mice and after treadmill exercise. Eccentric and high-intensity physical activity may exhibit a disease-promoting effect on skeletal muscles in desminopathy.
临床上和基因上多样化的人类肌原纤维肌病组的经典形态学特征是肌原纤维变性和结蛋白阳性蛋白聚集体的迹象。细丝蛋白C以及含新肌动蛋白结合重复序列蛋白1和2（xirp 1和xirp 2）在局部肌节的富集是肌原纤维损伤的标志物。本研究旨在（i）研究结蛋白病小鼠模型中细丝蛋白C和xirp 1/2阳性的肌节病变，（ii）开发一种量化xirp 1/2阳性肌节病变的方法，以及（iii）研究急性体育锻炼对R349P结蛋白敲入小鼠肌节病变形成的影响，该小鼠是人类R350P结蛋白病的模型。
通过xirp 1/2和细丝蛋白C免疫荧光对R349P和R405W结蛋白敲入、结蛋白敲除和W2711X细丝蛋白C敲入小鼠比目鱼肌中的肌节病变进行可视化。使用开源软件QuPath分析未运动和跑步机运动的R349P结蛋白敲入小鼠比目鱼肌的xirp 1/2共聚焦免疫荧光图像。
细丝蛋白C和xirp 1/2染色的肌肉显示，在杂合和纯合的R349P和R405W结蛋白敲入、纯结合蛋白敲除以及杂合和纯合W2711X细丝蛋白C敲入小鼠中存在同类肌节病变。对R349P结蛋白敲入小鼠的定量分析显示，（i）与野生型相比，未运动的杂合小鼠中的病变明显更多，纯合动物中的增加更为明显，以及（ii）在进行剧烈跑步机运动的杂合小鼠和野生型同胞中，每毫米肌节病变显著增加。
使用xirp 1/2免疫荧光图像量化肌节病变的QuPath工作流程显示，R349P结蛋白病小鼠以及跑步机运动后病变密度增加。离心和高强度体育活动可能对结蛋白病的骨骼肌表现出促病作用。
