Lemos-Silva Thais, De Neef Emma, Valgaerts Yarno, Simões Maria L
Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium.
Glob Chang Biol. 2025 Aug;31(8):e70382. doi: 10.1111/gcb.70382.
A variety of environmental factors including temperature and humidity influence mosquito physiology and behavior. However, their direct impact on innate immunity, the core mosquito defense system against pathogen infection, remains insufficiently understood. This is particularly important as climate change is likely already altering mosquito distribution. A key limitation in most mosquito studies is the use of unrealistic static temperature and humidity settings which fail to reflect natural environmental changes. To address this, we employed a novel approach, exposing Anopheles stephensi from egg to adult to diurnal fluctuations (+4°C and +10% relative humidity above the baseline). We then investigated the impact of these elevated fluctuating conditions on innate immune gene expression, development, and adult longevity. We show that realistic elevated temperature and humidity fluctuations prime basal immune responses and accelerate pre-adult development without reducing adult lifespan. Bacterial infections under these elevated fluctuating conditions lead to a complex reprogramming of mosquito innate immunity and enhanced survival of both larvae and adults. Furthermore, fluctuating elevated temperature and humidity alter the transcriptional activity of key promoters widely used to express transgenes in genetically modified mosquitoes, highlighting the potential environmental sensitivity of these malaria control strategies. These results suggest that while elevated conditions-driven immune priming could initially decrease A. stephensi's vectorial capacity, the observed post-bacterial challenge immune suppression could enhance susceptibility to Plasmodium, with potential significant implications for vector competence and malaria transmission. Our study findings highlight the need to incorporate realistic environmental variability in mosquito research to accurately predict the impact of climate on disease transmission.
包括温度和湿度在内的多种环境因素会影响蚊子的生理和行为。然而，它们对先天免疫（蚊子抵御病原体感染的核心防御系统）的直接影响仍未得到充分了解。鉴于气候变化可能已经在改变蚊子的分布，这一点尤为重要。大多数蚊子研究的一个关键局限在于使用了不切实际的静态温度和湿度设置，无法反映自然环境变化。为了解决这个问题，我们采用了一种新方法，让斯氏按蚊从卵到成虫暴露于昼夜波动环境（比基线温度高4°C，相对湿度高10%）。然后，我们研究了这些升高的波动条件对先天免疫基因表达、发育和成虫寿命的影响。我们发现，实际升高的温度和湿度波动会引发基础免疫反应并加速成虫前期发育，同时不会缩短成虫寿命。在这些升高的波动条件下的细菌感染会导致蚊子先天免疫的复杂重编程，并提高幼虫和成虫的存活率。此外，温度和湿度的波动升高会改变在转基因蚊子中广泛用于表达转基因的关键启动子的转录活性，凸显了这些疟疾控制策略对环境的潜在敏感性。这些结果表明，虽然升高条件驱动的免疫预激发最初可能会降低斯氏按蚊的传播能力，但观察到的细菌感染后的免疫抑制可能会增强对疟原虫的易感性，这对媒介能力和疟疾传播可能具有重大影响。我们的研究结果强调，在蚊子研究中需要纳入实际的环境变异性，以准确预测气候对疾病传播的影响。
