Sadanandappa Madhumala K, Bosco Giovanni
Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
J Exp Biol. 2024 Dec 15;227(24). doi: 10.1242/jeb.247234. Epub 2024 Dec 11.
Drosophila female germline development and maintenance require both local stem cell niche signaling and systemic regulation. Here, we show the indispensable function of the Drosophila melanogaster olfactory circuit in normal oogenesis and fecundity. Lack of olfactory inputs during development causes a reduction in germline stem cells. Although germline stem cells proliferate normally, the germline cysts undergo caspase-mediated apoptosis, leading to decreased follicle production and egg-laying in flies with defective olfaction. Strikingly, activation of olfactory circuits is sufficient to boost egg production, demonstrating that chemosensory-activated brain-derived inputs promote gamete development. Given the energy demands of oogenesis and its direct consequence on fitness, we propose that olfactory-stimulated systemic regulation evolved tightly with downstream diet-responsive pathways to control germline physiology in response to nutritional status. Additionally, these findings raise the possibility that sensory-mediated stem cell maintenance is a generalizable mechanism spanning a myriad of neuronal circuits, systems and species.
果蝇雌性生殖系的发育和维持既需要局部干细胞微环境信号传导，也需要系统性调节。在此，我们展示了果蝇嗅觉回路在正常卵子发生和繁殖力中的不可或缺的功能。发育过程中缺乏嗅觉输入会导致生殖系干细胞减少。虽然生殖系干细胞正常增殖，但生殖系囊肿会经历半胱天冬酶介导的细胞凋亡，导致嗅觉有缺陷的果蝇卵泡生成减少和产卵量降低。令人惊讶的是，嗅觉回路的激活足以提高产卵量，这表明化学感应激活的脑源性输入促进配子发育。鉴于卵子发生的能量需求及其对适应性的直接影响，我们提出嗅觉刺激的系统性调节与下游饮食反应途径紧密协同进化，以根据营养状况控制生殖系生理。此外，这些发现增加了一种可能性，即感觉介导的干细胞维持是一种广泛存在于众多神经元回路、系统和物种中的普遍机制。
