Malaria Parasite Development, Drug Resistance, Pathogenesis, and Genomics

在2012-2013年间，我们集中在三个主要研究领域：1)联合治疗和传播阻断药物的筛选和表征；2)利用约氏疟原虫/小鼠模型研究疟疾发病的分子机制；3)卵囊发育缺陷的分子基础。 我们已经完成并发表了一组可以阻止疟疾寄生虫传播的化合物的特征(Eastman等人，2013年，AAC 57,425)。与NCATS的科学家合作，我们正在进行大规模的药物组合筛选。有希望的药物组合已经被确定。我们还在评估钙离子和钠离子通道阻滞剂对寄生虫对青蒿素反应的影响。 利用鼠类疟疾寄生虫约氏疟原虫，我们在研究寄生虫与宿主的相互作用方面取得了很好的进展：1)我们继续评估与宿主细胞因子/趋化因子反应相关的基因座上的候选基因。其中一个候选基因已经被证明在等位基因替换后影响寄生虫的生长。2)我们发现I型干扰素在控制约氏疟原虫N67的原虫血症中起着重要作用。我们还证明了RNA聚合酶III和MDA5介导的信号转导有助于提高干扰素-I的应答。这部作品的一份手稿已经提交。3)建立并测试了约氏疟原虫基因组基因分型的微阵列平台。结果表明，该芯片用于寄生虫基因分型具有较高的可靠性和准确性。这部作品的一份手稿已经提交。4)我们已经将一个卵囊发育缺陷与约氏疟原虫6号染色体上的一个基因座联系起来，并正在测试该基因座上的候选基因。5)对寄主对一个遗传杂交后代的感染反应进行了全基因组连锁分析，确定了数百个与多种寄主基因的反应连锁的寄生虫遗传位点。6)对黑杨N67C和约氏黄杨进行了多次杂交，获得了52个后代。这些后代的基因类型和表型正在鉴定中。7)我们还与伯氏疟原虫Anna和P.berghei NK165杂交，获得了几个后代，用于鉴定与脑型疟疾相关的基因。最后，我们还对约氏疟原虫感染后细胞凋亡和坏死性下垂的分子机制进行了研究。了解宿主-寄生虫相互作用的分子机制将有助于开发有效的措施来控制寄生虫的发展及其引起的疾病。

In the year between 2012-2013, we focused on three major research area: 1) screening and characterizing drugs for combination therapy and transmission blocking; 2) studying molecular mechanisms of malaria pathogenesis using Plasmodium yoelii/mouse model; 3) molecular basis of an oocyst development defect. We have completed and published the work characterizing a group of compounds that can block malaria parasite transmission (Eastman et al 2013, AAC 57, 425). In collaboration with scientists in NCATS, we are performing large-scale screening of drug combinations. Promising drug combinations have been identified. We are also evaluating the effect of Ca++ and Na+ channel blockers on parasite response to artemisinin. Using rodent malaria parasite P. yoelii, we have made good progresses in studying parasite-host interaction in several directions: 1) We continue to evaluate candidate genes in the loci linked to host cytokine/chemokine response. One of the candidate genes has been shown to affect parasite growth after allelic replacement. 2) We showed that type I interferon (IFN-I) played an important role in controlling parasitemia of rodent malaria parasite Plasmodium yoelii nigeriensis N67. We also demonstrated that the RNA polymerase III and MDA5 mediated signaling contributed to the elevated IFN-I response. A manuscript from this work has been submitted. 3) We developed and tested a microarray platform for genotyping P. yoelii genome. We showed that the array was highly reliable and accurate in calling parasite genotype. A manuscript from this work has been submitted. 4) We have linked an oocyst development defect to a locus on chromosome 6 of P. yoelii and are testing candidate genes in the locus. 5) We have performed a genome-wide linkage analysis on host response to infection of progeny from a genetic cross and identified hundreds of parasite genetic loci linked to responses of many host genes. 6) We performed several additional crosses of P. y. negeriensis N67C and P. y. yoelii YM and have obtained 52 progeny. The genotypes and phenotypes of these progeny are being characterized. 7) We have also crossed P. berghei ANNA and P. berghei NK165 and obtained several progeny to identify genes linked to cerebral malaria. Finally, we are also studying the molecular mechanism of apoptosis and necroptosis after P. yoelii infection. Understanding the molecular mechanism of host-parasite interaction will allow development of effective measures for controlling parasite development and the disease it causes.