Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany.
Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
Elife. 2024 May 15;12:RP90529. doi: 10.7554/eLife.90529.
In most mammals, conspecific chemosensory communication relies on semiochemical release within complex bodily secretions and subsequent stimulus detection by the vomeronasal organ (VNO). Urine, a rich source of ethologically relevant chemosignals, conveys detailed information about sex, social hierarchy, health, and reproductive state, which becomes accessible to a conspecific via vomeronasal sampling. So far, however, numerous aspects of social chemosignaling along the vomeronasal pathway remain unclear. Moreover, since virtually all research on vomeronasal physiology is based on secretions derived from inbred laboratory mice, it remains uncertain whether such stimuli provide a true representation of potentially more relevant cues found in the wild. Here, we combine a robust low-noise VNO activity assay with comparative molecular profiling of sex- and strain-specific mouse urine samples from two inbred laboratory strains as well as from wild mice. With comprehensive molecular portraits of these secretions, VNO activity analysis now enables us to (i) assess whether and, if so, how much sex/strain-selective 'raw' chemical information in urine is accessible via vomeronasal sampling; (ii) identify which chemicals exhibit sufficient discriminatory power to signal an animal's sex, strain, or both; (iii) determine the extent to which wild mouse secretions are unique; and (iv) analyze whether vomeronasal response profiles differ between strains. We report both sex- and, in particular, strain-selective VNO representations of chemical information. Within the urinary 'secretome', both volatile compounds and proteins exhibit sufficient discriminative power to provide sex- and strain-specific molecular fingerprints. While total protein amount is substantially enriched in male urine, females secrete a larger variety at overall comparatively low concentrations. Surprisingly, the molecular spectrum of wild mouse urine does not dramatically exceed that of inbred strains. Finally, vomeronasal response profiles differ between C57BL/6 and BALB/c animals, with particularly disparate representations of female semiochemicals.
在大多数哺乳动物中，同种化学通讯依赖于复杂的身体分泌物中的半化学物质释放，随后由犁鼻器（VNO）进行刺激检测。尿液是一种富含行为相关化学信号的丰富来源，它传递了有关性、社会等级、健康和生殖状态的详细信息，这些信息可以通过犁鼻器采样被同种动物获取。然而，迄今为止，沿犁鼻器途径的社会化学信号传递的许多方面仍然不清楚。此外，由于几乎所有关于犁鼻器生理学的研究都是基于从近交系实验室小鼠中提取的分泌物，因此仍然不确定这些刺激物是否提供了在野外可能更相关的线索的真实代表。在这里，我们将强大的低噪声犁鼻器活性测定与两种近交系实验室小鼠和野生小鼠的性别和品系特异性尿液样本的比较分子分析相结合。通过对这些分泌物的全面分子分析，犁鼻器活性分析现在使我们能够：（i）评估尿液中的性别/品系选择性“原始”化学信息是否以及在多大程度上可以通过犁鼻器采样获取；（ii）确定哪些化学物质具有足够的区分能力来指示动物的性别、品系或两者；（iii）确定野生小鼠分泌物的独特程度；和（iv）分析犁鼻器反应谱在不同品系之间是否存在差异。我们报告了化学信息的性别选择性和特别是品系选择性的犁鼻器表示。在尿液“分泌组”中，挥发性化合物和蛋白质都具有足够的区分能力，可以提供性别和品系特异性的分子指纹。虽然雄性尿液中总蛋白含量大大丰富，但雌性则以总体上相对较低的浓度分泌更多种类的蛋白。令人惊讶的是，野生小鼠尿液的分子谱并没有显著超过近交系的分子谱。最后，C57BL/6 和 BALB/c 动物的犁鼻器反应谱不同，特别是雌性半化学物质的表示差异很大。
