Schnitzerlein Miriam, Greto Eric, Wegner Anja, Möller Anna, Aust Oliver, Ben Brahim Oumaima, Blumenthal David B, Zaburdaev Vasily, Uderhardt Stefan
Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany.
PLoS Comput Biol. 2025 May 29;21(5):e1011859. doi: 10.1371/journal.pcbi.1011859. eCollection 2025 May.
Resident tissue macrophages (RTMs) are essential for tissue homeostasis. Their diverse functions, from monitoring interstitial fluids to clearing cellular debris, are accompanied by characteristic morphological changes that reflect their functional status. While current knowledge of macrophage behavior comes primarily from in vitro studies, their dynamic behavior in vivo is fundamentally different, necessitating a more physiologically relevant approach to their understanding. In this study, we employed intravital imaging to generate dynamic data from peritoneal RTMs in mice under various conditions and developed a comprehensive image processing pipeline to quantify RTM morphodynamics over time, defining human-interpretable cell size and shape features. These features allowed for the quantitative and qualitative differentiation of cell populations in various functional states, including pro- and anti-inflammatory activation and endosomal dysfunction. The study revealed that under steady-state conditions, RTMs exhibit a wide range of morphodynamical phenotypes, constituting a naïve morphospace of behavioral motifs. Upon challenge, morphodynamic patterns changed uniformly at the population level but predominantly within the constraints of this naïve morphospace. Notably, aged animals displayed a markedly shifted naïve morphospace, indicating drastically different behavioral patterns compared to their young counterparts. The developed method also proved valuable in optimizing explanted tissue setups, bringing RTM behavior closer to the physiological native state. Our versatile approach thus provides novel insights into the dynamic behavior of bona fide macrophages in vivo, enabling the distinction between physiological and pathological cell states and the assessment of functional tissue age on a population level.
驻留组织巨噬细胞（RTM）对于组织稳态至关重要。它们具有多种功能，从监测组织间液到清除细胞碎片，同时伴随着反映其功能状态的特征性形态变化。虽然目前对巨噬细胞行为的了解主要来自体外研究，但它们在体内的动态行为却截然不同，因此需要一种更符合生理实际的方法来理解它们。在本研究中，我们采用活体成像技术在各种条件下从小鼠腹膜RTM生成动态数据，并开发了一套全面的图像处理流程来量化RTM随时间的形态动力学，定义可人为解读的细胞大小和形状特征。这些特征能够对处于各种功能状态的细胞群体进行定量和定性区分，包括促炎和抗炎激活以及内体功能障碍。研究表明，在稳态条件下，RTM表现出广泛的形态动力学表型，构成了一个行为模式的原始形态空间。受到刺激后，形态动力学模式在群体水平上均匀变化，但主要是在这个原始形态空间的限制范围内。值得注意的是，老年动物的原始形态空间明显偏移，表明其行为模式与年轻动物相比有显著差异。所开发的方法在优化外植组织设置方面也被证明是有价值的，使RTM行为更接近生理原始状态。因此，我们的通用方法为体内真正巨噬细胞的动态行为提供了新的见解，能够区分生理和病理细胞状态，并在群体水平上评估功能性组织年龄。
