Intestinal tuft cell immune privilege enables norovirus persistence.

The persistent murine norovirus strain MNV is a model for human norovirus and enteric viral persistence. MNV causes chronic infection by directly infecting intestinal tuft cells, rare chemosensory epithelial cells. Although MNV induces functional MNV-specific CD8 T cells, these lymphocytes fail to clear infection.

The KDM6A-KMT2D-p300 axis regulates susceptibility to diverse coronaviruses by mediating viral receptor expression.

Identification of host determinants of coronavirus infection informs mechanisms of pathogenesis and may provide novel therapeutic targets. Here, we demonstrate that the histone demethylase KDM6A promotes infection of diverse coronaviruses, including SARS-CoV, SARS-CoV-2, MERS-CoV and mouse hepatitis virus (MHV) in a demethylase activity-independent manner. Mechanistic studies reveal that KDM6A promotes viral entry by regulating expression of multiple coronavirus receptors, including ACE2, DPP4 and Ceacam1.

Tuft-cell-intrinsic and -extrinsic mediators of norovirus tropism regulate viral immunity.

Murine norovirus (MNoV) is a model for human norovirus and for interrogating mechanisms of viral tropism and persistence. We previously demonstrated that the persistent strain MNoV infects tuft cells, which are dispensable for the non-persistent strain MNoV. We now show that diverse MNoV strains require tuft cells for chronic enteric infection.

UBX Domain Protein 6 Positively Regulates JAK-STAT1/2 Signaling.

Type I/III IFNs induce expression of hundreds of IFN-stimulated genes through the JAK/STAT pathway to combat viral infections. Although JAK/STAT signaling is seemingly straightforward, it is nevertheless subjected to complex cellular regulation. In this study, we show that an ubiquitination regulatory X (UBX) domain-containing protein, UBXN6, positively regulates JAK-STAT1/2 signaling.

Norovirus evolution in immunodeficient mice reveals potentiated pathogenicity via a single nucleotide change in the viral capsid.

Interferons (IFNs) are key controllers of viral replication, with intact IFN responses suppressing virus growth and spread. Using the murine norovirus (MNoV) system, we show that IFNs exert selective pressure to limit the pathogenic evolutionary potential of this enteric virus. In animals lacking type I IFN signaling, the nonlethal MNoV strain CR6 rapidly acquired enhanced virulence via conversion of a single nucleotide.

CD300lf Conditional Knockout Mouse Reveals Strain-Specific Cellular Tropism of Murine Norovirus.

Noroviruses are a leading cause of gastrointestinal infection in humans and mice. Understanding human norovirus (HuNoV) cell tropism has important implications for our understanding of viral pathogenesis. Murine norovirus (MNoV) is extensively used as a surrogate model for HuNoV.

Genome-wide CRISPR Screens Reveal Host Factors Critical for SARS-CoV-2 Infection.

Identification of host genes essential for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may reveal novel therapeutic targets and inform our understanding of coronavirus disease 2019 (COVID-19) pathogenesis. Here we performed genome-wide CRISPR screens in Vero-E6 cells with SARS-CoV-2, Middle East respiratory syndrome CoV (MERS-CoV), bat CoV HKU5 expressing the SARS-CoV-1 spike, and vesicular stomatitis virus (VSV) expressing the SARS-CoV-2 spike. We identified known SARS-CoV-2 host factors, including the receptor ACE2 and protease Cathepsin L.

Genome-wide CRISPR screen reveals host genes that regulate SARS-CoV-2 infection.

Identification of host genes essential for SARS-CoV-2 infection may reveal novel therapeutic targets and inform our understanding of COVID-19 pathogenesis. Here we performed a genome-wide CRISPR screen with SARS-CoV-2 and identified known SARS-CoV-2 host factors including the receptor ACE2 and protease Cathepsin L. We additionally discovered novel pro-viral genes and pathways including the SWI/SNF chromatin remodeling complex and key components of the TGF-β signaling pathway.

CD300lf is the primary physiologic receptor of murine norovirus but not human norovirus.

Murine norovirus (MNoV) is an important model of human norovirus (HNoV) and mucosal virus infection more broadly. Viral receptor utilization is a major determinant of cell tropism, host range, and pathogenesis. The bona fide receptor for HNoV is unknown.

The intestinal regionalization of acute norovirus infection is regulated by the microbiota via bile acid-mediated priming of type III interferon.

Evidence has accumulated to demonstrate that the intestinal microbiota enhances mammalian enteric virus infections. For example, we and others previously reported that commensal bacteria stimulate acute and persistent murine norovirus infections. However, in apparent contradiction of these results, the virulence of murine norovirus infection was unaffected by antibiotic treatment.

Norovirus Attachment and Entry.

Human norovirus is a major human pathogen causing the majority of cases of viral gastroenteritis globally. Viral entry is the first step of the viral life cycle and is a significant determinant of cell tropism, host range, immune interactions, and pathogenesis. Bile salts and histo-blood group antigens are key mediators of norovirus entry; however, the molecular mechanisms by which these molecules promote infection and the identity of a potential human norovirus receptor remain unknown.

Utility of clinical parameters, cystourethroscopy, and magnetic resonance imaging in the preoperative diagnosis of urethral diverticula.

Introduction And Hypothesis: Our purpose was to assess the accuracy of history and physical, cystourethroscopy, and magnetic resonance imaging (MRI) in preoperative diagnosis of urethral diverticula.

Methods: This was a retrospective review of all patients who underwent surgical excision of periurethral masses between 1998 and 2009. Presenting symptoms and examination and cystourethroscopic findings were noted.

Demonstration of a perihepatic abscess communicating with a fistula from the small bowel on hepatobiliary imaging.

Abscess formation after abdominal surgery is not an uncommon complication. It is much less common for a collection to be the result of a fistulous tract from the bowel. We describe a patient who underwent a Tc-99m hepatobiliary (Choletec) scan for the workup of a perihepatic abscess, which confirmed the presence of a fistulous tract from the small bowel to a perihepatic collection.

Effect of maximal endometrial thickness on outcome after frozen embryo transfer.

The largest study to date on the association of endometrial thickness and subsequent pregnancy rates following frozen embryo transfer with the endometrium prepared by estrogen and progesterone found no improved or adverse outcome if the endometrial thickness was > or = standard deviations above the mean. Neither was there a trend noted for thin endometria.