Baly Christine, Aioun Josiane, Badonnel Karine, Lacroix Marie-Christine, Durieux Didier, Schlegel Claire, Salesse Roland, Caillol Monique
Equipe Récepteurs et Communication Chimique, UMR1197 Institut National de la Recherche Agronomique-Université Paris 11, CRJ, Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France.
Brain Res. 2007 Jan 19;1129(1):130-41. doi: 10.1016/j.brainres.2006.10.030. Epub 2006 Dec 12.
Leptin is an adipocyte-derived cytokine that regulates body weight mainly via the long form of the leptin receptor (Ob-Rb). Leptin and its receptors are expressed in several tissues, suggesting that leptin might also be effective peripherally. We hypothesized that, as shown in taste cells, leptin and its receptors isoforms (Ob-Rs) could be present in the rat olfactory mucosa (OM). Using RT-PCR, light and electron microscopy immunohistochemistry (ICC), we found that different isoforms of the receptor were expressed in OM and localized in sustentacular cells and in a subpopulation of maturating neurons; in addition, immunoreactivity was also present in differentiated neurons and enriched at the cilia membranes, where the odorants bind to their receptors. Moreover, using RT-PCR, ICC and RIA measurements, we showed that leptin is synthesized locally in the olfactory mucosa. In addition, we demonstrate that fasting causes a significant enhanced transcription of both leptin and Ob-Rs in rat OM by quantitative RT-PCR data. Altogether, these results strongly suggested that leptin, acting as an endocrine or a paracrine factor, could be an important regulator of olfactory function, as a neuromodulator of the olfactory message in cilia of mature olfactory receptors neurons (ORN), but also for the homeostasis of this complex tissue, acting on differentiating neurons and on sustentacular cells.
瘦素是一种由脂肪细胞分泌的细胞因子，主要通过长型瘦素受体（Ob-Rb）调节体重。瘦素及其受体在多种组织中表达，这表明瘦素在周围组织中可能也发挥作用。我们推测，正如在味觉细胞中所显示的那样，瘦素及其受体异构体（Ob-Rs）可能存在于大鼠嗅黏膜（OM）中。通过逆转录聚合酶链反应（RT-PCR）、光镜和电镜免疫组织化学（ICC），我们发现受体的不同异构体在嗅黏膜中表达，并定位于支持细胞和成熟神经元的一个亚群中；此外，在分化的神经元中也存在免疫反应性，且在气味剂与其受体结合的纤毛膜处富集。此外，通过RT-PCR、ICC和放射免疫分析（RIA）测量，我们表明瘦素在嗅黏膜中局部合成。另外，通过定量RT-PCR数据，我们证明禁食会导致大鼠嗅黏膜中瘦素和Ob-Rs的转录显著增强。总之，这些结果强烈表明，瘦素作为一种内分泌或旁分泌因子，可能是嗅觉功能的重要调节因子，作为成熟嗅觉受体神经元（ORN）纤毛中嗅觉信息的神经调节剂，而且对于这个复杂组织的稳态也很重要，作用于分化中的神经元和支持细胞。
