Infectious Diseases Division, Department of Internal Medicine, St, Louis, Missouri, USA.
J Biomed Sci. 2012 Feb 9;19(1):21. doi: 10.1186/1423-0127-19-21.
Most filarial nematodes contain Wolbachia symbionts. The purpose of this study was to examine the effects of doxycycline on gene expression in Wolbachia and adult female Brugia malayi.
Brugia malayi infected gerbils were treated with doxycycline for 6-weeks. This treatment largely cleared Wolbachia and arrested worm reproduction. RNA recovered from treated and control female worms was labeled by random priming and hybridized to the Version 2- filarial microarray to obtain expression profiles.
Results showed significant changes in expression for 200 Wolbachia (29% of Wolbachia genes with expression signals in untreated worms) and 546 B. malayi array elements after treatment. These elements correspond to known genes and also to novel genes with unknown biological functions. Most differentially expressed Wolbachia genes were down-regulated after treatment (98.5%). In contrast, doxycycline had a mixed effect on B. malayi gene expression with many more genes being significantly up-regulated after treatment (85% of differentially expressed genes). Genes and processes involved in reproduction (gender-regulated genes, collagen, amino acid metabolism, ribosomal processes, and cytoskeleton) were down-regulated after doxycycline while up-regulated genes and pathways suggest adaptations for survival in response to stress (energy metabolism, electron transport, anti-oxidants, nutrient transport, bacterial signaling pathways, and immune evasion).
Doxycycline reduced Wolbachia and significantly decreased bacterial gene expression. Wolbachia ribosomes are believed to be the primary biological target for doxycycline in filarial worms. B. malayi genes essential for reproduction, growth and development were also down-regulated; these changes are consistent with doxycycline effects on embryo development and reproduction. On the other hand, many B. malayi genes involved in energy production, electron-transport, metabolism, anti-oxidants, and others with unknown functions had increased expression signals after doxycycline treatment. These results suggest that female worms are able to compensate in part for the loss of Wolbachia so that they can survive, albeit without reproductive capacity. This study of doxycycline induced changes in gene expression has provided new clues regarding the symbiotic relationship between Wolbachia and B. malayi.
大多数丝虫含有沃尔巴克氏体共生菌。本研究旨在研究多西环素对沃尔巴克氏体和成年雌性马来丝虫基因表达的影响。
用多西环素治疗感染沙鼠的马来丝虫 6 周。这种治疗方法基本上清除了沃尔巴克氏体并阻止了蠕虫的繁殖。从处理过和未处理过的雌性蠕虫中提取 RNA，用随机引物标记，然后与丝状虫第 2 版微阵列杂交，以获得表达谱。
结果表明，治疗后沃尔巴克氏体的 200 个（未处理蠕虫中表达信号的沃尔巴克氏体基因的 29%）和 546 个 B. malayi 阵列元件的表达发生了显著变化。这些元素对应于已知基因，也对应于具有未知生物学功能的新基因。大多数差异表达的沃尔巴克氏体基因在治疗后下调（98.5%）。相比之下，多西环素对 B. malayi 基因表达的影响是混合的，治疗后更多的基因显著上调（差异表达基因的 85%）。与繁殖有关的基因和过程（性别调节基因、胶原蛋白、氨基酸代谢、核糖体过程和细胞骨架）在多西环素治疗后下调，而上调的基因和途径表明为应对应激而生存的适应（能量代谢、电子传递、抗氧化剂、营养物质运输、细菌信号通路和免疫逃避）。
多西环素降低了沃尔巴克氏体的数量，并显著降低了细菌基因的表达。沃尔巴克氏体核糖体被认为是多西环素在丝虫中的主要生物学靶标。对繁殖、生长和发育至关重要的 B. malayi 基因也下调；这些变化与多西环素对胚胎发育和繁殖的影响一致。另一方面，许多参与能量产生、电子传递、代谢、抗氧化剂和其他具有未知功能的 B. malayi 基因在多西环素治疗后表达信号增加。这些结果表明，雌性蠕虫能够在一定程度上补偿沃尔巴克氏体的损失，从而存活下来，尽管没有繁殖能力。这项关于多西环素诱导基因表达变化的研究为沃尔巴克氏体和 B. malayi 之间的共生关系提供了新的线索。
