Project description:Examination of the transcriptional changes occurring in the skin upon mosquito bite at different times of day. Approximately 20 A. aegypti mosquitoes were allowed to bite mice on the ear at two timepoints, zeitgeber time (ZT)1 and ZT11, corresponding to dawn and dusk, respectively. Twenty-four hours later, biopsies from the mosquito bite sites were collected and transcriptomic analyses were performed. Biopsies from mice that did not receive a mosquito bite served as controls
Project description:Mosquitoes transmit many flaviviruses of global public health significance. Efficient viral transmission to mammalian hosts requires mosquito salivary factors that modulate local host responses, such as recruitment of virus-permissive myeloid cells to the bite sites. However, the specific salivary components facilitating viral transmission and their mechanisms of action remain largely unknown. Here, we showed that a female mosquito salivary gland-specific protein, named Aedes aegypti Neutrophil Recruitment Protein (AaNRP), acts as a key salivary component to facilitate the transmission of Zika (ZIKV) and dengue (DENV) viruses. AaNRP promotes a rapid influx of neutrophils followed by virus-susceptible myeloid cells toward mosquito bite sites, which facilitate establishment of local infection and systemic dissemination. Mechanistically, AaNRP engages TLR1 and TLR4 of skin resident macrophages and activates MyD88-dependent NF-κB signaling to induce the expression of neutrophil chemoattractants. Inhibition of MyD88-NF-κB with dietary resveratrol, a phytochemical, neutralizes the AaNRP effects, thus reducing flavivirus transmission by mosquitoes. This study offers mechanistic insight into saliva-aided viral transmission and provides a potential prophylactic target.
Project description:This study is a collaboration with Phil Spence and Jean Langhorne at NIMR, Mill Hill where Phil is studying the differences in aetiology of rodent malaria when mice are infected by mosquito bite versus intraperitoneal injection of blood stage parasites. The aim is to determining transcriptomic differences using RNA-Seq between parasites transmitted by mosquito and those transmitted by injection. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/Protocol: Mice were bled out at 6 days post-infection, and RNA was extracted from purified parasite populations using Trizol reagent and DNase treated. Poly A+ mRNA was purified from total RNA using oligo dT dyna bead selection and libraries were created using a modified RNA-seq protocol, where RNA was fragmented using Covaris AFA sonication instead of metal ions. The samples were sequenced on an Illumina HiSeq 2000.
Project description:Spotted Fever Group Rickettsiae (SFGR) can cause mild to fatal illness. The early interaction between the host and rickettsia in skin is largely unknown, and the pathogenesis of severe rickettsiosis remains an important topic. A surveillance of SFGR infection by PCR of blood and skin biopsies followed by sequencing, and immunohistochemical detection was performed on patients with a recent tick bite from 2013–2016. Humoral and cutaneous immune profiles were evaluated for different SFGR cases by serum cytokine and chemokine detection, skin immunohistochemical (IHC) staining, and transcriptome sequencing (RNA-seq). A total of 111 SFGR cases were identified, including 79 Candidatus Rickettsia tarasevichiae (CRT), 22 R. raoultii, 8 R. sibirica, and 2 R. heilongjiangensis. The sensitivity to detect SFGR in skin biopsies (9/24, 37.5 %) was significantly higher than in blood samples (105/2671, 3.9 %) (p<0.05). As early as one day after the tick bite, rickettsia could be detected in the skin. R. sibirica infection was more severe than CRT and R. raoultii. Increased levels of serum IL18, IP10, and MIG, and decreased IL2 in R. sibirica febrile patients were observed compared to CRT febrile infections. RNA-seq and IHC staining could not discriminate SFGR infected and uninfected tick-fed skin lesions. The type I interferon (IFN) response was differently expressed between R. sibirica and R. raoultii infection at the cutaneous interface. Severe rickettsiosis might be inclined to induce an increased type I IFN response on the infected skin but which were complicated by the bite of a tick eliciting immune cell infiltration.
Project description:Most animals restrict their activity to specific part of the day, being either diurnal, nocturnal, or crepuscular. The genetic basis underlying this diurnal preference is largely unknown. Under laboratory conditions, Drosophila melanogaster is crepuscular, showing a bi-modal activity profile. However, recent experiments in our lab indicated that high variability among individuals exist, particularly in strains that derive from different wild populations. By assembling together flies from various geographical strains, we have generated a highly diverse population whose progeny exhibited extreme diurnal preference, including diurnal and nocturnal flies. We have used this population as a starting point for an artificial selection experiment in which we selected males that show the most extreme diurnal preference and mated them to their sisters. The response to selection was strong, and already after 10 selection cycles we obtained highly diurnal (D) and nocturnal (N) strains. Another strain that was not selected and showed intermediate behaviour (crepuscular) served as a control (C). These strains provide us with a unique opportunity to understand the genetics of diurnal preference.
Project description:Malaria parasites transmitted by mosquito bite are remarkably efficient in establishing human infections. The infection process requires ~30 minutes and is highly complex as quiescent sporozoites injected with mosquito saliva must be rapidly activated in the skin, migrate through the body, and infect the liver. This process is poorly understood for Plasmodium vivax due to low infectivity in the in vitro models. To study this skin-to-liver stage of malaria, we developed quantitative bioassays coupled with transcriptomics to evaluate parasite changes linked with mammalian microenvironmental factors. Our in vitro phenotype and RNA-seq analyses revealedkey microenvironmental relationships with distinct biological functions. M ost notable, preservation of sporozoite quiescence by exposure to insect-like factors coupled with strategic activation limits untimely activation of invasion-associated genes to dramatically increase hepatocyte invasion rates. We also report the first transcriptomic analysis of the P. vivax sporozoite interaction in salivary glands identifying 118 infection-related differentially-regulated Anopheles dirus genes. These results provide important new insights in malaria parasite biology and identify priority targets for antimalarial therapeutic interventions to block P. vivax infection.
Project description:To examine the effects of 20E treatment on mosquito gene expression, treated mosquito cells were examined by RNA-seq to determine the influence of 20E treatment.