Publications by authors named "Raeann M Shimak"

Background: Breast cancer is the most common malignancy in women, and is both pathologically and genetically heterogeneous, making early detection and treatment difficult. A subset of breast cancers express normal levels of REST (repressor element 1 silencing transcription factor) mRNA but lack functional REST protein. Loss of REST function is seen in ~ 20% of breast cancers and is associated with a more aggressive phenotype and poor prognosis.

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Type I interferons (IFNs) are key mediators of the innate immune response. Although members of this family of cytokines signal through a single shared receptor, biochemical and functional variation exists in response to different IFN subtypes. While previous work has demonstrated that type I IFNs are essential to control infection by chikungunya virus (CHIKV), a globally emerging alphavirus, the contributions of individual IFN subtypes remain undefined.

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The innate immune system protects cells against viral pathogens in part through the autocrine and paracrine actions of alpha/beta interferon (IFN-α/β) (type I), IFN-γ (type II), and IFN-λ (type III). The transcription factor interferon regulatory factor 1 (IRF-1) has a demonstrated role in shaping innate and adaptive antiviral immunity by inducing the expression of IFN-stimulated genes (ISGs) and mediating signals downstream of IFN-γ. Although ectopic expression experiments have suggested an inhibitory function of IRF-1 against infection of alphaviruses in cell culture, its role remains unknown.

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In 2013, chikungunya virus (CHIKV) transmission was documented in the Western Hemisphere, and the virus has since spread throughout the Americas with more than 1.8 million people infected in more than 40 countries. CHIKV targets the joints, resulting in symmetric polyarthritis that clinically mimics rheumatoid arthritis and can endure for months to years.

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Canine leishmaniosis (CanL) is caused by Leishmania infantum, an obligate intracellular protozoan parasite, endemic in U.S. hunting dog populations.

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We evaluated the mechanism by which neutralizing human monoclonal antibodies inhibit chikungunya virus (CHIKV) infection. Potently neutralizing antibodies (NAbs) blocked infection at multiple steps of the virus life cycle, including entry and release. Cryo-electron microscopy structures of Fab fragments of two human NAbs and chikungunya virus-like particles showed a binding footprint that spanned independent domains on neighboring E2 subunits within one viral spike, suggesting a mechanism for inhibiting low-pH-dependent membrane fusion.

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Pathogen glycolipids, including Leishmania spp. lipophosphoglycan (LPG) and Mycobacterium tuberculosis mannosylated lipoarabinomannan (ManLAM), modulate essential interactions with host phagocytic cells. Polysaccharide and lipid components promote immunomodulation.

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