Biology subjects

Griffin, E. F.

Publications and source records attributed to Griffin, E. F..

3 recordsLinked to original sources

bioRxiv2024

Pandemic Risk Assessment for a Swine Influenza A Virus in Comparative Human Substrates

Swine influenza A viruses pose a public health concern as novel and circulating strains occasionally spill over into human hosts, with the potential to cause disease. Crucial to preempting these events is the use of a threat assessment framework for human populations. However, established guidelines do not specify what animal models or in vitro substrates should be used. We completed an assessment of a contemporary swine influenza isolate, A/swine/GA/A27480/2019, using animal models and human cell substrates. Infection studies in vivo revealed high replicative ability and a pathogenic phenotype in the swine host with replication corresponding to a complementary study performed in swine primary respiratory epithelial cells. However, replication was limited in human primary cell substrates. This contrasted with our findings in the Calu-3 cell line, which demonstrated a replication profile on par with the 2009 pandemic H1N1 virus. These data suggest selection of models is important for meaningful risk assessment. Article Summary LineA novel swine influenza A virus was rigorously assessed for pandemic potential in animal models and human surrogate culture models, illustrating a wide range in potential public health risk dependent on the model utilized.

microbiology↗

bioRxiv2023

Swine influenza A virus isolates containing the pandemic H1N1 origin matrix gene elicit greater disease in the murine model

Since the 1990s, endemic North American swine influenza A viruses (swFLUAV) contained an internal gene segment constellation referred to as the triple reassortment internal gene (TRIG) cassette. In 2009, the H1N1 pandemic (pdmH1N1) virus spilled back into swine, but did not become endemic. However, the pdmH1N1 did contribute the matrix gene segment (pdmM) to the swFLUAVs circulating in the pig population; which replaced the classical swine matrix gene (swM) found in the TRIG cassette, suggesting that the pdmM has a fitness benefit. Others have shown that swFLUAV containing the pdmM have greater neuraminidase activity and transmission efficiency compared to viruses containing the swM gene segment. We hypothesized that the matrix gene could also affect disease and utilized two infection models, resistant BALB/c and susceptible DBA/2 mice, to assess swFLUAV pathogenicity. We infected BALB/c and DBA/2 mice with a panel of H1 and H3 swFLUAVs containing the swM or pdmM gene and measured lung virus titers, morbidity, mortality, and lung histopathology. H1 influenza strains containing the pdmM gene caused greater morbidity and mortality in both resistant and susceptible murine strains, while H3 swFLUAVs caused no clinical disease. However, both H1 and H3 swFLUAVs containing the pdmM replicated to higher viral titers in the lungs and pdmM containing H1 viruses induced greater histological changes compared to swM H1 viruses. While the surface glycoproteins contribute to swFLUAV pathogenicity, and other genes also influence disease, these data suggest that the origin of the matrix gene also contributes to pathogenicity of swFLUAV viruses in mice.

microbiology↗

bioRxiv2019

VPS41 recessive mutation causes ataxia and dystonia with retinal dystrophy and mental retardation by inhibiting HOPS function and mTORC1 signaling

The vacuolar protein sorting protein 41 (VPS41) is a neuroprotective protein in models of Parkinsons disease (PD). As part of the HOPS (Homotypic fusion and Protein Sorting) complex, VPS41 regulates fusion of lysosomes with late endosomes and autophagosomes. Independent of HOPS, VPS41 regulates transport of newly synthesized lysosomal membrane proteins and secretory proteins. Here we report two brothers with compound heterozygous mutations in VPS41 (VPS41R662* and VPS41S285P), born to healthy and non-consanguineous parents. Both patients displayed transient retinal dystrophy, ataxia and dystonia, with brain MRI findings of cerebellar atrophy and a thin saber-shape corpus callosum. Patient-derived fibroblasts contained enzymatically active lysosomes that were poorly reached by endocytic cargo and failed to attract the mTORC1 complex. Consequently, transcription factor TFE3, a driver of autophagy and lysosomal genes, showed continuous nuclear localization which resulted in elevated LC3-II levels and an impaired response to nutrient starvation. CRISPR/CAS VPS41 HeLa knockout cells showed a similar phenotype that could be rescued by wildtype VPS41 but not by VPS41S285P or VPS41R662*. mTORC1 inhibition was also seen after knockout of HOPS subunits VPS11 or VPS18. Regulated neuropeptide secretion in PC12 VPS41 knockout cells was rescued by VPS41S285P expression, indicating that this HOPS-independent function was preserved. Co-expression of the VPS41S285P and VPS41R662* variants in a C. elegans model of PD abolished the protective effect of VPS41 against -synuclein-induced neurodegeneration. We conclude that both disease-associated VPS41 variants specifically abrogate HOPS function, which leads to a delay in endocytic cargo delivery to lysosomes, mTORC1 inhibition and irresponsiveness to autophagic clues. Our studies signify a link between HOPS function and mTORC1 signaling and imply that HOPS function is required for the neuroprotective effect of VPS41 in PD.

cell biology↗