Leyria Jimena, El-Mawed Hanine, Orchard Ian, Lange Angela B
Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada.
Front Physiol. 2021 Feb 10;12:624165. doi: 10.3389/fphys.2021.624165. eCollection 2021.
Using the blood-sucking kissing bug, as an experimental model, we have studied the involvement of insulin-like peptides (ILPs) and adipokinetic hormone (AKH) signaling in carbohydrate metabolism, focusing on the regulation of the trehalose-specific facilitated transporter (Rhopr-TRET), particularly in the ovaries. We find that trehalose stores in ovaries increase after feeding, synchronously with the beginning of vitellogenesis, but that the transcript expression of enzymes involved in trehalose synthesis show no changes between unfed and blood-fed animals. However, an eightfold increase in transcript expression is observed in the ovaries post-blood meal. and assays using exogenous insulins and Rhopr-AKH, reveal that is up-regulated in ovaries by both peptide families. In accordance with these results, when ILP and AKH signaling cascades are impaired using RNA interference, transcript is down-regulated. In addition, trehalose injection induces an up-regulation of transcript expression and suggests an activation of insulin signaling. Overall, the results support the hypothesis of a direct trehalose uptake by ovaries from the hemolymph through Rhopr-TRET, regulated by ILP and/or AKH. We also show that Rhopr-TRET may work cooperatively with AKH signaling to support the release of trehalose from the ovaries into the hemolymph during the unfed (starved) condition. In conclusion, the results indicate that in females of , trehalose metabolism and its hormonal regulation by ILP and AKH play critical roles in adapting to different nutritional conditions and physiological states.
我们以吸血猎蝽为实验模型，研究了胰岛素样肽（ILPs）和脂肪动激素（AKH）信号传导在碳水化合物代谢中的作用，重点关注海藻糖特异性易化转运体（Rhopr-TRET）的调节，特别是在卵巢中的调节。我们发现，取食后卵巢中的海藻糖储备增加，与卵黄发生开始同步，但海藻糖合成相关酶的转录本表达在未取食和取食血液的动物之间没有变化。然而，取食血液后卵巢中转录本表达增加了八倍。使用外源性胰岛素和Rhopr-AKH进行的测定表明，这两个肽家族均可使卵巢中的该转运体上调。与这些结果一致，当使用RNA干扰损害ILP和AKH信号级联时，该转运体的转录本下调。此外，注射海藻糖可诱导该转运体转录本表达上调，并表明胰岛素信号被激活。总体而言，这些结果支持以下假设：卵巢通过Rhopr-TRET直接从血淋巴中摄取海藻糖，受ILP和/或AKH调节。我们还表明，Rhopr-TRET可能与AKH信号协同作用，以支持在未取食（饥饿）状态下卵巢中的海藻糖释放到血淋巴中。总之，结果表明，在猎蝽雌性中，海藻糖代谢及其受ILP和AKH的激素调节在适应不同营养条件和生理状态中起关键作用。
