Mahamid Amir, Ben-Menahem David
Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheba 8410501, Israel.
Pharmaceuticals (Basel). 2024 Sep 25;17(10):1267. doi: 10.3390/ph17101267.
BACKGROUND/OBJECTIVES: The gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and their receptors are major regulators of reproduction in mammals and are absent in insects. We previously established transgenic lines expressing a constitutively active human LH receptor variant (LHR) and the wild-type receptor (LHR; inactive in the absence of an agonist). That study showed that ubiquitously expression of LHR-but not of LHR-resulted in pupal lethality, and targeted expression in midline cells resulted in thorax/bristles defects. To further study the model for an in vivo drug screening platform, we investigated here whether expressing LHR in the fly gonads alters reproduction, as shown in a transgenic mice model.
The receptor was expressed in somatic cells of the gonads using the tissue-specific -Gal4 driver. Western blot analysis confirmed receptor expression in the ovaries.
A fecundity assay indicated that the ectopic expression of LHR resulted in a decrease in egg laying compared to control flies carrying, but not expressing the transgene (~40% decrease in two independent fly lines, < 0.001). No significant reduction in the number of laid eggs was seen in flies expressing the LHR (<10% decrease compared to non-driven flies, > 0.05). The decreased egg laying demonstrates a phenotype of the active receptor in the fly gonads, the prime target organs of the gonadotropins in mammals. We suggest that this versatile model can be used for the pharmacological search for gonadotropin modulators.
This is expected to provide: (a) new mimetic drug candidates (receptor-agonists/signaling-activators) for assisted reproduction treatment, (b) blockers for potential fertility regulation, and (c) leads relevant for the purpose of managing extra gonadotropic reported activities.
背景/目的：促性腺激素黄体生成素（LH）和卵泡刺激素（FSH）及其受体是哺乳动物生殖的主要调节因子，而在昆虫中不存在。我们之前建立了表达组成型活性人LH受体变体（LHR）和野生型受体（LHR；在没有激动剂时无活性）的转基因品系。该研究表明，LHR的普遍表达而非LHR的表达导致蛹期致死，并且在中线细胞中的靶向表达导致胸部/刚毛缺陷。为了进一步研究体内药物筛选平台的模型，我们在此研究了在果蝇性腺中表达LHR是否会改变繁殖，如转基因小鼠模型所示。
使用组织特异性-Gal4驱动子在性腺的体细胞中表达受体。蛋白质印迹分析证实了受体在卵巢中的表达。
繁殖力测定表明，与携带但不表达转基因的对照果蝇相比，LHR的异位表达导致产卵量减少（两个独立果蝇品系中减少约40%，P<0.001）。在表达LHR的果蝇中未观察到产卵数量的显著减少（与未驱动的果蝇相比减少<10%，P>0.05）。产卵量的减少证明了果蝇性腺中活性受体的一种表型，而性腺是哺乳动物促性腺激素的主要靶器官。我们认为这种通用模型可用于促性腺激素调节剂的药理学研究。
预计这将提供：（a）用于辅助生殖治疗的新的模拟药物候选物（受体激动剂/信号激活剂），（b）潜在生育调节的阻滞剂，以及（c）与管理额外促性腺激素报道活性目的相关的先导化合物。
