The Cross-Border Biotech Blog

Biotechnology, Health and Business in Canada, the United States and Worldwide

Friday Science Review: May 4, 2012

The innate immune system is the first line of defense against infection of the host organism by pathogens and in this system, type I interferons are a critical component in limiting viral replication. Indeed, type I interferons are already marketed or in development for their anti-viral and immune modulating activities.

Levels of type I interferons are subject to control and rapid induction in response to the recognition of a pathogen by the host organism’s pattern-recognition receptors (e.g. Toll-like receptors – topically a struggling area of development with Idera’s recent phase II failure of a TLR9 inhibitor for advanced head and neck cancer). Production of the type I interferons is rapidly stimulated through a cascade that includes regulation of both transcription and translation, with the transcriptional activator NF-kB being an important site of regulation. A paper in Nature Immunology from a international consortium of researchers led by the Sonenberg lab at McGill University presents data showing that phosphorylation of the translation factor eIF4E is a key mechanism in regulating NF-kB’s ability to activate type I interferon production. Using mice in which the Ser209 phosphorylation site in eIF4E is removed, they showed indirect enhancement of NF-kB activity through decreased translation of NF-kB’s inhibitor IkBa. Furthermore, they showed that in these mice the replication of three different RNA viruses was impaired and that the mice were more resistant vesicular stomatitis virus (VSV) infection associated neurological damage.

Currently Mnk1 and Mnk2 are the only known kinases to phosphorylate eIF4E in mice, with Mnk2 being constitutively active and Mnk1 being activated in response to mitogens, growth factors and hormones, which places Mnk1 in the cascade initiating response to pathogen detection. Earlier this year researchers at the Child and Family Research Institute at the University of British Columbia identified Mnk1 as mediating Trastuzumab (Herceptin) resistance in HER2-positive breast cancers, which excitingly identifies Mnk1 as an unexploited potential target for multiple therapeutic categories, including cancer, viral infections and immune modulation.

Other publications

  • A programmable droplet-based microfluidic device applied to multiparameter analysis of single microbes and microbial communities. PNAS. University of British Columbia
  • Innate immune response to rift valley Fever virus in goats. PLoS Negl Trop Dis. National Center for Foreign Animal Disease, Canadian Food Inspection Agency
  • Trappin-2/Elafin Modulate Innate Immune Responses of Human Endometrial Epithelial Cells to PolyI∶C. PLoS One. McMaster University
  • Inflammation-Driven Reprogramming of CD4(+)Foxp3(+) Regulatory T Cells into Pathogenic Th1/Th17 T Effectors Is Abrogated by mTOR Inhibition in vivo. PLoS One. McGill University
  • Co-Expression of α9β1 Integrin and VEGF-D Confers Lymphatic Metastatic Ability to a Human Breast Cancer Cell Line MDA-MB-468LN. PLoS One. University of Western Ontario
  • Early steps in oxidation-induced SOD1 misfolding: Implications for non-amyloid protein aggregation in familial ALS. J. Mol. Biol. University of Toronto

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