Immune stimulation and malaria infection impose reproductive costs in Anopheles gambiae via follicular apoptosis
Immune stimulation and malaria infection impose reproductive costs in Anopheles gambiae via follicular apoptosis
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DOI：
10.1016/j.micinf.2005.06.026
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发表时间：
2006-02-01
影响因子：
5.8
通讯作者：
Hurd, H
中科院分区：
文献类型：
--
作者：
Ahmed, AM;Hurd, H
防御机制的使用被认为是一种代价高昂的生活史特征。在疟疾病媒冈比亚按蚊中，生殖成本与体液和细胞先天免疫反应以及疟疾感染有关。与疟疾感染相关的发育中的卵母细胞的再吸收是在卵泡细胞程序性死亡或凋亡之前发生的。在这里，我们证明，当蚊子受到人工免疫激发剂诱导黑色素化反应或体液抗菌活性时，卵巢滤泡上皮细胞也会发生凋亡。半胱天冬酶是参与细胞凋亡的关键半胱氨酸蛋白酶。在未处理的吸血蚊子卵巢卵泡发育过程中，约4.0%的上皮细胞检测到caspase样活性。与生理盐水注射相比，脂多糖注射可显著增加抗黄体微球菌的体液活性，并显著增加257.7%的卵泡凋亡。黑化还会诱发卵泡凋亡，接种Sephadex C-25和G-25的蚊子的卵泡凋亡分别比假注射组增加106.25%和134.37%。与未感染约氏疟原虫的蚊子相比，感染约氏疟原虫的蚊子卵巢卵泡凋亡显著增加440.9%。因此，在调查的时间点上，感染比人工免疫激发剂有更大的效果。卵泡上皮细胞的死亡已被证明会导致卵泡吸收，从而导致卵子产量的减少。我们提出冈比亚拟南蚕的生殖适应性和免疫防御之间的权衡是通过诱导卵泡细胞凋亡来实现的，不同的免疫反应通过相同的途径施加成本。(c) 2005 Elsevier SAS。版权所有。
The employment of defense mechanisms is recognized as a costly life-history trait. In the malaria vector Anopheles gambiae, reproductive costs have been associated with both humoral and cellular innate immune responses and also with malaria infection. The resorption of developing oocytes associated with malaria infection is preceded by the programmed cell death, or apoptosis, of follicular cells. Here we demonstrate that apoptosis in ovarian follicular epithelial cells also occurs when mosquitoes are subjected to artificial immune-elicitors that induce a melanization response or humoral antimicrobial activity. Caspases are key cysteine proteases involved in apoptosis. Caspase-like activity was detected in epithelial cells in approximately 4.0% of the developing ovarian follicles of untreated, blood-fed, mosquitoes. Lipopolysaccharide injection resulted in a significant increase in anti-Micrococcus luteus humoral activity and a significant increase of 257.7% of follicles exhibiting apoptosis compared to results after saline injections. Melanization also triggered follicular apoptosis, which increased by 106.25% or 134.37% in Sephadex C-25 or G-25 bead-inoculated mosquitoes, respectively, compared to that in sham-injected ones. Ovaries from Plasmodium yoelii nigeriensis-infected mosquitoes exhibited a significant increase in follicular apoptosis of 440.9% compared to non-infected ones. Thus, at the time point investigated, infection had a much greater effect than artificial immune-elicitors. Death of follicular epithelial cells has been shown to lead to follicle resorption and hence a decrease in egg production. We propose the trade-off between reproductive fitness and immune defense in A. gambiae operates via the induction of apoptosis in ovarian follicles and that different immune responses impose costs via the same pathway. (c) 2005 Elsevier SAS. All rights reserved.