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Author

Michael J. McFadden

Other affiliations: Michigan State University
Bio: Michael J. McFadden is an academic researcher from Duke University. The author has contributed to research in topics: Interferon & Innate immune system. The author has an hindex of 10, co-authored 14 publications receiving 514 citations. Previous affiliations of Michael J. McFadden include Michigan State University.

Papers
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Journal ArticleDOI
TL;DR: It is demonstrated that both the immune deficiency (IMD) and Toll pathways are activated by the Wolbachia strain wAlbB upon its introduction into A. aegypti, indicating that host innate immunity is utilized to establish and promote host-microbial symbiosis.
Abstract: A host's immune system plays a central role in shaping the composition of the microbiota and, in return, resident microbes influence immune responses. Symbiotic associations of the maternally transmitted bacterium Wolbachia occur with a wide range of arthropods. It is, however, absent from the dengue and Zika vector mosquito Aedes aegypti in nature. When Wolbachia is artificially forced to form symbiosis with this new mosquito host, it boosts the basal immune response and enhances the mosquito's resistance to pathogens, including dengue, Zika virus and malaria parasites. The mechanisms involved in establishing a symbiotic relationship between Wolbachia and A. aegypti, and the long-term outcomes of this interaction, are not well understood. Here, we have demonstrated that both the immune deficiency (IMD) and Toll pathways are activated by the Wolbachia strain wAlbB upon its introduction into A. aegypti. Silencing the Toll and IMD pathways via RNA interference reduces the wAlbB load. Notably, wAlbB induces peptidoglycan recognition protein (PGRP)-LE expression in the carcass of A. aegypti, and its silencing results in a reduction of symbiont load. Using transgenic mosquitoes with stage-specific induction of the IMD and Toll pathways, we have shown that elevated wAlbB infection in these mosquitoes is maintained via maternal transmission. These results indicate that host innate immunity is utilized to establish and promote host-microbial symbiosis. Our results will facilitate a long-term projection of the stability of the Wolbachia-A. aegypti mosquito system that is being developed to control dengue and Zika virus transmission to humans.

97 citations

Journal ArticleDOI
TL;DR: This work uses a new high-throughput RNA structure probing technology to identify RNA regions with tertiary folds and discovers that roughly one-third of the dengue virus RNA genome forms higher-order interactions, many in regions functionally important for replication.
Abstract: RNA virus genomes are efficient and compact carriers of biological information, encoding information required for replication both in their primary sequences and in higher-order RNA structures. However, the ubiquity of RNA elements with higher-order folds—in which helices pack together to form complex 3D structures—and the extent to which these elements affect viral fitness are largely unknown. Here we used single-molecule correlated chemical probing to define secondary and tertiary structures across the RNA genome of dengue virus serotype 2 (DENV2). Higher-order RNA structures are pervasive and involve more than one-third of nucleotides in the DENV2 genomic RNA. These 3D structures promote a compact overall architecture and contribute to viral fitness. Disrupting RNA regions with higher-order structures leads to stable, nonreverting mutants and could guide the development of vaccines based on attenuated RNA viruses. The existence of extensive regions of functional RNA elements with tertiary folds in viral RNAs, and likely many other messenger and noncoding RNAs, means that there are significant regions with pocket-containing surfaces that may serve as novel RNA-directed drug targets.

73 citations

Journal ArticleDOI
TL;DR: It is found that w AlbB reduced female fecundity and caused a minor decrease in male mating competiveness, and wAlbB increased the life span of both male and female mosquitoes when they were maintained solely on sugar meals; however, there was no impact on the life spans of blood-fed females.
Abstract: Background: Wolbachia is a maternally transmitted intracellular bacterium that is estimated to infect up to 65% of insect species, but it is not naturally present in Anopheles malaria vectors. Wolbachia-based strategies for malaria vector control can be developed either through population replacement to reduce vectorial capacity or through population suppression to reduce the mosquito population. We have previously generated An. stephensi mosquitoes carrying a stable wAlbB Wolbachia infection and have demonstrated their ability to invade wild-type laboratory populations and confer resistance to Plasmodium on these populations. Methods: We assessed wAlbB-associated fitness by comparing the female fecundity, immature development and survivorship, body size, male mating competiveness, and adult longevity of the infected An. stephensi to that of wild-type mosquitoes. Results: We found that wAlbB reduced female fecundity and caused a minor decrease in male mating competiveness. We also observed that wAlbB increased the life span of both male and female mosquitoes when they were maintained solely on sugar meals; however, there was no impact on the life span of blood-fed females. In addition, wAlbB did not influence either immature development and survivorship or adult body sizes.

53 citations

Journal ArticleDOI
TL;DR: This review highlights the mechanisms used by cells to detect viral pathogens in the cytosol, and recent advances in the field of cytosolic sensing of viruses.

39 citations


Cited by
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Journal ArticleDOI
14 May 2020-Cell
TL;DR: Functional investigation of the unknown transcripts and RNA modifications discovered in this study will open new directions to the understanding of the life cycle and pathogenicity of SARS-CoV-2.

1,626 citations

Journal ArticleDOI
TL;DR: New and emerging methods to characterize and quantify the epitranscriptome are reviewed, and new concepts — in some cases, controversies — are discussed regarding the authors' understanding of the mechanisms and functions of m6A readers, writers and erasers are discussed.
Abstract: RNA methylation to form N6-methyladenosine (m6A) in mRNA accounts for the most abundant mRNA internal modification and has emerged as a widespread regulatory mechanism that controls gene expression in diverse physiological processes. Transcriptome-wide m6A mapping has revealed the distribution and pattern of m6A in cellular RNAs, referred to as the epitranscriptome. These maps have revealed the specific mRNAs that are regulated by m6A, providing mechanistic links connecting m6A to cellular differentiation, cancer progression and other processes. The effects of m6A on mRNA are mediated by an expanding list of m6A readers and m6A writer-complex components, as well as potential erasers that currently have unclear relevance to m6A prevalence in the transcriptome. Here we review new and emerging methods to characterize and quantify the epitranscriptome, and we discuss new concepts - in some cases, controversies - regarding our understanding of the mechanisms and functions of m6A readers, writers and erasers.

1,126 citations

Journal ArticleDOI
25 Mar 2020-Gut
TL;DR: Attention to patients with COVID-19 with non-classic symptoms should increase to protect health providers, and sequence mutation of SARS-CoV-2 with m6A methylation and changed binding capacity with ACE2 was showed.
Abstract: Objective The SARS-CoV-2-infected disease (COVID-19) outbreak is a major threat to human beings. Previous studies mainly focused on Wuhan and typical symptoms. We analysed 74 confirmed COVID-19 cases with GI symptoms in the Zhejiang province to determine epidemiological, clinical and virological characteristics. Design COVID-19 hospital patients were admitted in the Zhejiang province from 17 January 2020 to 8 February 2020. Epidemiological, demographic, clinical, laboratory, management and outcome data of patients with GI symptoms were analysed using multivariate analysis for risk of severe/critical type. Bioinformatics were used to analyse features of SARS-CoV-2 from Zhejiang province. Results Among enrolled 651 patients, 74 (11.4%) presented with at least one GI symptom (nausea, vomiting or diarrhoea), average age of 46.14 years, 4-day incubation period and 10.8% had pre-existing liver disease. Of patients with COVID-19 with GI symptoms, 17 (22.97%) and 23 (31.08%) had severe/critical types and family clustering, respectively, significantly higher than those without GI symptoms, 47 (8.14%) and 118 (20.45%). Of patients with COVID-19 with GI symptoms, 29 (39.19%), 23 (31.08%), 8 (10.81%) and 16 (21.62%) had significantly higher rates of fever >38.5°C, fatigue, shortness of breath and headache, respectively. Low-dose glucocorticoids and antibiotics were administered to 14.86% and 41.89% of patients, respectively. Sputum production and increased lactate dehydrogenase/glucose levels were risk factors for severe/critical type. Bioinformatics showed sequence mutation of SARS-CoV-2 with m6A methylation and changed binding capacity with ACE2. Conclusion We report COVID-19 cases with GI symptoms with novel features outside Wuhan. Attention to patients with COVID-19 with non-classic symptoms should increase to protect health providers.

1,032 citations

Journal ArticleDOI
TL;DR: This review highlights recent progress in understanding the function of N6-methyladenosine (m6A), the most abundant internal mark on eukaryotic mRNA, in light of the specific biological contexts of m6A effectors, and emphasizes the importance of context for RNA modification regulation and function.

909 citations

Journal ArticleDOI
TL;DR: In this review, recent advances in m6A research are summarized, and it is highlighted how these new findings have reshaped the understanding of how m 6A is regulated in the transcriptome.
Abstract: In recent years, m6A has emerged as an abundant and dynamically regulated modification throughout the transcriptome. Recent technological advances have enabled the transcriptome-wide identification of m6A residues, which in turn has provided important insights into the biology and regulation of this pervasive regulatory mark. Also central to our current understanding of m6A are the discovery and characterization of m6A readers, writers, and erasers. Over the last few years, studies into the function of these proteins have led to important discoveries about the regulation and function of m6A. However, during this time our understanding of these proteins has also evolved considerably, sometimes leading to the reversal of early concepts regarding the reading, writing and erasing of m6A. In this review, we summarize recent advances in m6A research, and we highlight how these new findings have reshaped our understanding of how m6A is regulated in the transcriptome.

718 citations