Geier Benedikt, Gil-Mansilla Esther, Liutkevičiūtė Zita, Hellinger Roland, Vanden Broeck Jozef, Oetjen Janina, Liebeke Manuel, Gruber Christian W
Department of Symbiosis, Max Planck Institute for Marine Microbiology, Bremen 28359, Germany.
Department of Pediatrics and Infectious Diseases, Stanford School of Medicine, Stanford, CA 94305, USA.
PNAS Nexus. 2023 Apr 25;2(5):pgad144. doi: 10.1093/pnasnexus/pgad144. eCollection 2023 May.
Neuropeptides are important regulators of animal physiology and behavior. Hitherto the gold standard for the localization of neuropeptides have been immunohistochemical methods that require the synthesis of antibody panels, while another limiting factor has been the brain's opacity for subsequent in situ light or fluorescence microscopy. To address these limitations, we explored the integration of high-resolution mass spectrometry imaging (MSI) with microtomography for a multiplexed mapping of neuropeptides in two evolutionary distant ant species, and . For analyzing the spatial distribution of chemically diverse peptide molecules across the brain in each species, the acquisition of serial mass spectrometry images was essential. As a result, we have comparatively mapped the three-dimensional (3D) distributions of eight conserved neuropeptides throughout the brain microanatomy. We demonstrate that integrating the 3D MSI data into high-resolution anatomy models can be critical for studying organs with high plasticity such as brains of social insects. Several peptides, like the tachykinin-related peptides (TK) 1 and 4, were widely distributed in many brain areas of both ant species, whereas others, for instance myosuppressin, were restricted to specific regions only. Also, we detected differences at the species level; many peptides were identified in the optic lobe of , but only one peptide (ITG-like) was found in this region in . Building upon MS imaging studies on neuropeptides in invertebrate model systems, our approach leverages correlative MSI and computed microtomography for investigating fundamental neurobiological processes by visualizing the unbiased 3D neurochemistry in its complex anatomic environment.
神经肽是动物生理和行为的重要调节因子。迄今为止，神经肽定位的金标准一直是免疫组织化学方法，该方法需要合成抗体组，而另一个限制因素是大脑对于后续原位光学或荧光显微镜检查的不透明性。为了解决这些限制，我们探索了将高分辨率质谱成像（MSI）与显微断层扫描相结合，以对两种进化距离较远的蚂蚁物种中的神经肽进行多重映射。为了分析每个物种大脑中化学性质多样的肽分子的空间分布，获取连续的质谱图像至关重要。结果，我们比较地绘制了八种保守神经肽在整个脑微观解剖结构中的三维（3D）分布。我们证明，将3D MSI数据整合到高分辨率解剖模型中对于研究具有高可塑性的器官（如群居昆虫的大脑）可能至关重要。几种肽，如速激肽相关肽（TK）1和4，在两种蚂蚁的许多脑区中广泛分布，而其他肽，例如肌抑制素，则仅局限于特定区域。此外，我们在物种水平上检测到差异；在 的视叶中鉴定出许多肽，但在 该区域仅发现一种肽（类整合素）。基于对无脊椎动物模型系统中神经肽的MS成像研究，我们的方法利用相关MSI和计算机显微断层扫描，通过在其复杂解剖环境中可视化无偏差的3D神经化学来研究基本的神经生物学过程。
