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Biology subjects

Ghannam, M.

Publications and source records attributed to Ghannam, M..

3 recordsLinked to original sources

High Throughput Screening with a Primary Human Mucociliary Airway Model Identifies a Small Molecule with Anti-SARS-CoV-2 Activity

Respiratory viruses (e.g. influenza, RSV, SARS etc.) attack the proximal airway and cause a wide spectrum of diseases for which we have limited therapies. To date, a few primary human stem cell-based models of the proximal airway have been reported for drug discovery but scaling them up to a higher throughput platform remains a significant challenge. Here we present a microscale, primary human stem cell-based proximal airway model of SARS-CoV-2 infection, which is amenable to moderate-to-high throughput drug screening. The model recapitulates the heterogeneity of infection seen among different patients and with different SARS-CoV-2 variants. We applied this model to screen 2100 compounds from targeted drug libraries using an image-based quantification method. While there were heterogeneous responses across variants for host factor targeting compounds, the direct acting antivirals showed a consistent response and we characterized a new antiviral drug that is effective against both the parental strain and the Omicron variant.

cell biology↗

Characterization of Genomic Diversity In Bacteriophages Infecting Rhodococcus

Bacteriophages are globally ubiquitous viruses that infect bacteria. With nearly 4,000 sequenced genomes of phages infecting the phylum Actinobacteria available, genomic analyses of these actinobacteriophage genomes has been instrumental in uncovering a diverse genomic landscape often characterized by genome mosaicism. Here, we describe the genomic characterization of 57 sequenced phages capable of infecting the genus Rhodococcus. These phages were previously isolated at multiple institutions by students in the SEA-PHAGES program using four different species of Rhodococcus. Most Rhodococcus phages have been grouped into 4 clusters based on their genomic similarities; 13 phages are singletons too genetically distinct for clustering. These clusters and singletons contain Siphoviridae and Myoviridae phages, and most contain integrase and repressor genes indicative of a potential lysogenic life cycle. The genome size of these phages varies from 14,270 bp to 142,586 bp and their G+C% content ranges from 41.2-68.4%, while that of their Rhodococcus hosts typically exceeds 60%. Through comparative genomic analyses, it was revealed that these Rhodococcus phages display high intracluster similarity but low intercluster similarity, despite their shared ability to infect the same host genus. Additionally, these Rhodococcus phages share similarities with phages that infect other Actinobacterial hosts such as Gordonia, Streptomyces and Arthrobacter.

microbiology↗

The septate junction component Bark beetle is required for Drosophila intestinal barrier function and homeostasis

Age-related loss of intestinal barrier function has been found across species, and the causes remain unknown. The intestinal epithelial barrier is maintained by tight junctions (TJs) in mammals and septate junctions (SJs) in insects. Specialized tricellular junctions (TCJs) are found at the nexus of three adjacent cell membranes, and we showed previously that aging results in mis-localization of the tricellular SJ (tSJ) component Gliotactin (Gli) in enterocytes (ECs) of the Drosophila melanogaster intestine. In embryonic epithelia, the tSJ protein Bark beetle (Bark) recruits Gli to tSJs, which prompted us to investigate Bark function in the intestine. Bark protein localization decreases at tSJs in aged flies. EC-specific bark depletion in young flies led to hallmarks of intestinal aging and shortened lifespan, whereas depletion of bark in progenitor cells reduced Notch activity, biasing differentiation toward the secretory lineage. Together, our data implicate Bark in EC maturation, maintenance of intestinal barrier integrity, and homeostasis. Understanding the assembly and maintenance of tSJs to ensure barrier integrity may lead to strategies to improve tissue integrity when function is compromised.

cell biology↗