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The membrane (M) glycoprotein of coronaviruses (CoVs) serves as the nidus for virion assembly. Using a yeast two-hybrid screen, we identified the interaction of the cytosolic tail of Murine Hepatitis Virus (MHV-CoV) M protein with Myosin Vb (MYO5B), specifically with the alternative splice variant of cellular MYO5B including exon D (MYO5B+D), which mediates interaction with Rab10. When co-expressed in human lung epithelial A549 and canine kidney epithelial MDCK cells, MYO5B+D co-localized with the MHV-CoV M protein, as well as with the M proteins from Porcine Epidemic Diarrhea Virus (PEDV-CoV), Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome 2 (SARS-CoV-2). Co-expressed M proteins and MYO5B+D co-localized with endogenous Rab10 and Rab11a. We identified point mutations in MHV-CoV M that blocked the interaction with MYO5B+D in yeast 2-hybrid assays. One of these point mutations (E121K) was previously shown to block MHV-CoV virion assembly and its interaction with MYO5B+D. The E to K mutation at homologous positions in PEDV-CoV, MERS-CoV and SARS-CoV-2 M proteins also blocked colocalization with MYO5B+D. The knockdown of Rab10 blocked the co-localization of M proteins with MYO5B+D and was rescued by re-expression of CFP-Rab10. Our results suggest that CoV M proteins traffic through Rab10-containing systems, in association with MYO5B+D. 

Acinar to ductal metaplasia (ADM) occurs in the pancreas in response to tissue injury and is a potential precursor for adenocarcinoma. The goal of these studies was to define the populations arising from genetically wild type ADM, the associated transcriptionalchanges, and to identify markersof disease progression. Acinar cells were lineage-traced with enhanced yellow fluorescent protein (EYFP)to follow their fate upon injury. Transcripts of over 13,000 EYFP+ cells were determined using single-cellRNA sequencing (scRNA-seq). Single-celltrajectories were generated. Data were compared to gastric metaplasia and human pancreatitis. Results were confirmed by immunostaining and electron microscopy. Surgical specimens of chronic pancreatitis from 15 patients were evaluatedby immunostaining. scRNA-seq of ADM revealed emergence of a mucin/ductal population (Muc6+, Tff2+) resembling gastric pyloric, gland-base cells. Lineage trajectories suggest that this pyloric metaplasia is an intermediate cell identity between acinar cells and the generation of metaplastic tuft and enteroendocrine cells (EECs). 3-D electron microscopy demonstrates that all identified lineages populate ADM lesions. EECs exhibit substantial heterogeneity, including emergence of enterochromaffin (5-HT+) and delta (SST+) cells. Human pancreatitis shows a similar pyloric metaplasia phenotype anda conserved transcriptional program. Under conditions of chronic injury, acinar cells undergo pyloric metaplasia to mucinous progenitor-like populations, some of which can then seed disparate tuft cell and EEC lineages. EEC subtypes are diverse with the potential to direct disease progression. This program is conserved in human pancreatitis, providing insightinto early events in pancreasdiseases.