Neuropathological characterization of a novel TANK binding kinase (TBK1) gene loss of function mutation associated with amyotrophic lateral sclerosis
NEUROPATHOLOGY AND APPLIED NEUROBIOLOGY
Authors: Weinreich, M.; Shepheard, S. R.; Verber, N.; Wyles, M.; Heath, P. R.; Highley, J. R.; Kirby, J.; Shaw, P. J.
Abstract
Aims Mutations in TANK binding kinase gene (TBK1) are causative in amyotrophic lateral sclerosis (ALS), however correlations between clinical features and TBK1 mutations have not been fully elucidated. We aimed to identify and compare TBK1 mutations to clinical features in a cohort of ALS patients from Northern England. Methods TBK1 mutations were analysed in 290 ALS cases. Immunohistochemistry was performed in brain and spinal cord of one case with a novel in-frame deletion. Results Seven TBK1 variants were identified, including one novel in-frame deletion (p.85delIle). In silico analysis and literature suggested four variants were pathogenic, and three were variants of uncertain significance or benign. Post-mortem immunohistochemistry established an individual with the novel in-frame deletion had classical ALS and Type B FTLD-TDP pathology, with no changes in TBK1 staining or interferon regulatory factor IRF3. Conclusions TBK1 mutations were present in 1.38% of our cohort, and screening showed no clear genotype-phenotype associations compared to other genetic and sporadic ALS cases. TBK1 immunohistochemistry was consistent with previously published literature and we are the first to show no differential expression of interferon regulatory factor IRF3, a downstream effector of TBK1 in the immune pathway, in the TBK1-mutant tissue, compared to controls.
Porcine deltacoronavirus (PDCoV) infection antagonizes interferon-lambda 1 production
VETERINARY MICROBIOLOGY
Authors: Liu, Shudan; Fang, Puxian; Ke, Wenting; Wang, Jing; Wang, Xunlei; Xiao, Shaobo; Fang, Liurong
Abstract
Porcine deltacoronavirus (PDCoV) is a novel swine enteropathogenic coronavirus that causes watery diarrhea, vomiting and mortality in nursing piglets. Type III interferons (IFN-lambda s) are the major antiviral cytokines in intestinal epithelial cells, the target cells in vivo for PDCoV. In this study, we found that PDCoV infection remarkably inhibited Sendai virus-induced IFN-lambda 1 production by suppressing transcription factors IRF and NF-kappa B in IPI-2I cells, a line of porcine intestinal mucosal epithelial cells. We also confirmed that PDCoV infection impeded the activation of IFN-lambda 1 promoter stimulated by RIG-I, MDA5 and MAVS, but not by TBK1 and IRF1. Although the expression levels of IRF1 and MAVS were not changed, PDCoV infection resulted in reduction of the number of peroxisomes, the platform for MAVS to activate IRF1, and subsequent type III IFN production. Taken together, our study demonstrates that PDCoV suppresses type III IFN responses to circumvent the host's antiviral immunity.