Biology subjects

Sutherland, S.

Publications and source records attributed to Sutherland, S..

5 recordsLinked to original sources

bioRxiv2026

An Ovol1 Variant in Endothelial Cells Regulates Slug and is Essential for Pathological Angiogenesis

During development, the blood vasculature expands by sprouting angiogenesis, but the programs that guide this process can become dysregulated in the pathological angiogenesis of neovascular diseases leading to excessive disorganized blood vessels. We previously reported that in endothelial cells, the pro-mesenchymal transcription factor Slug critically regulates angiogenesis through a partial and reversible endothelial-to-mesenchymal transition (pEndoMT); however, the upstream regulators that activate Slug and may contribute to pathological activation of the pEndoMT pathway in disease are still poorly understood. Here, we show that endothelial cells express an unusual low molecular weight variant of Ovol1 - a zinc-finger transcription factor that regulates mesenchymal transition in epithelial cells. Ovol1 and Slug are co-expressed in angiogenic endothelial cells, and using ChIP, we confirm direct Ovol1 binding to the endogenous Slug gene at a species-conserved binding motif. Whereas Ovol1 is typically a transcriptional repressor in epithelial cells, we find using a combination of silencing RNA and lentiviral overexpression constructs that the endothelial Ovol1 variant upregulates Slug, and is sufficient to drive pEndoMT marker expression and enhance endothelial cell migratory capacity. Silencing of Ovol1 abolished sprouting angiogenesis in a 3D in vitro sprouting angiogenesis assay, whereas constitutive overexpression of Ovol1 produced overaggressive and disorganized hypersprouting that depends upon Slug. We generated Ovol1 or Slug endothelial-specific knockout mice (Ovol1ECKO and SlugECKO) and found that healthy developmental angiogenesis of the neonatal mouse retina proceeds relatively normally in knockout animals. By contrast, Ovol1 was reduced in established post-natal blood vessels but became strongly re-expressed in tumor endothelial cells, and we found that colorectal cancer syngraft growth was significantly reduced in both Ovol1ECKO and SlugECKO mice alongside a failure of tumor angiogenesis. Lastly, neovascularization in the oxygen-induced retinopathy (OIR) model was also reduced in SlugECKO mice. In conclusion, we report that an endothelial Ovol1 variant upregulates Slug and drives a mesenchymal-like state, and that this Ovol1-Slug pEndoMT signaling axis is essential for pathological angiogenesis in neovascular disease models.

cell biology↗

bioRxiv2026

Differential Metabolite Production Underlies Disruption of the Cystic Fibrosis Airway Microbiota by Pathogens

Cystic fibrosis (CF) is a multisystem disease characterized by the accumulation of mucus in the airways that promotes pathogen colonization, leading to respiratory exacerbations, lung failure, and death. Culture-independent approaches have revealed that the CF airway harbors a complex microbiota, including opportunistic pathogens and bacteria that colonize the oropharynx. Here, we reanalyzed 5,260 16S rRNA gene microbiota datasets to infer ecological associations between members of the CF microbiota. We determined that pathogens are more likely to proliferate and dominate when present, while oropharyngeal bacteria are more likely to form persistent communities. Further, we found higher diversity and increasing numbers of inferred interactions were positively associated with lung function. In contrast, pathogens were negatively associated both with each other and with oropharyngeal bacteria, suggesting that they may disrupt the microbiota. To validate these predictions, we cultured 1,597 bacterial isolates from 96 people with CF and performed 12,542 coculture assays against eight representative CF pathogenic and oropharyngeal bacteria. 23% of these interactions resulted in growth inhibition. While Pseudomonas isolates were, on average, the most inhibitory, we observed variable activity among isolates. We then confirmed that Pseudomonas aeruginosa isolates, even those from the same donor and timepoint, exhibited significant differences in their metabolome and bioactivity profiles that correlated with acquisition of mutations. Together, our results suggest that pathogens may disrupt the CF microbiota and bloom in part through differential metabolite production. Furthermore, these data highlight that characterizing multiple isolates is necessary to capture the full landscape of chemically mediated interactions within microbial communities. ImportanceThe cystic fibrosis (CF) airway harbors a complex microbiota, including oropharyngeal bacteria and opportunistic pathogens that establish chronic infections and cause lung failure. We confirmed that microbiota diversity is correlated with health and that a pathogen-dominated microbiota is associated with reduced lung function. We then inferred microbial interactions, which suggested that pathogens are able to disrupt the microbiota. To validate these predictions, we cultured bacterial isolates from people with CF and performed thousands of coculture assays, finding that approximately one-quarter of interactions resulted in growth inhibition. Pseudomonas broadly inhibited other members of the CF airway microbiota. However, we observed marked variability in bioactivity and metabolite profiles of Pseudomonas aeruginosa isolates, even from the same donor at the same time. Our results suggest that pathogens disrupt the CF microbiota, possibly through bioactive metabolite production, and that characterizing multiple isolates is necessary to capture the complete picture of interactions in these communities.

microbiology↗

bioRxiv2026

The 3D Ultrastructure of C. elegans Gut Granules

We identify an endoderm-restricted organelle in published volume electron microscopy datasets of C. elegans embryos. The organelle consists of a tubular ring surrounding a membrane-bound compartment harboring a prominent dense particle and exhibits a basal polarity and size concordant with canonical gut granules. This finding offers ultrastructural detail to recent evidence that gut granules are bi-lobed organelles with two distinct compartments.

cell biology↗

bioRxiv2026

Chemical genomics screening reveals novel functions for unannotated genes in Vibrio cholerae C6706

Vibrio cholerae, the causative agent of cholera, remains a major global health burden despite ongoing initiatives for vaccination and improved sanitation. Much of the V. cholerae life cycle occurs in aquatic environments, requiring gene functions that enable survival under diverse stresses associated with this niche and during the transition to the human host. Although numerous V. cholerae genome sequences are available, functional annotation across its pan-genome remains incomplete, and many annotated genes lack experimental validation. In this study, we employed a chemical genomics approach to profile fitness phenotypes across 104 diverse stress conditions using a library of 3,026 single-gene mutants of V. cholerae C6706, a widely used research strain. In total, we identified significant growth phenotypes for 1,518 mutants, of which 88 correspond to unannotated (hypothetical or putative) genes. Together, these data provide a comprehensive resource for exploring gene function in V. cholerae, supported by detailed quality metrics and open-access tools to facilitate community-driven discovery. AUTHOR SUMMARYAlthough many bacterial pathogens have been extensively sequenced, we still know relatively little about what many of their genes actually do. In many cases, gene functions are solely predicted by computer algorithms but have not been confirmed in the laboratory, and we can assume that some of those predictions may be incorrect. Chemical genomics -- a method that tests thousands of single-gene mutants under different stresses -- can help reveal what these genes are responsible for. Using this approach, we screened a library of Vibrio cholerae C6706 mutants under 104 different conditions. We found that more than half of the mutants showed measurable effects on growth, including many genes that were previously uncharacterized. Here, we describe our experimental pipeline, present key quality checks, and share how other researchers can use this dataset as a resource to explore V. cholerae mutant phenotypes.

systems biology↗

bioRxiv2019

Beta 1 Integrin Signaling Mediates Pancreatic Ductal Adenocarcinoma Resistance to MEK Inhibition

Pancreatic cancer, one of the deadliest human malignancies, has a dismal 5-year survival rate of 9%. The high mortality rate can be attributed to multiple factors, including late diagnosis and lack of effective therapies. KRAS is the most commonly mutated gene in pancreatic cancer, but clinical agents that directly target mutant KRAS are not available. Several effector pathways are activated downstream of oncogenic Kras, including MAPK signaling. MAPK signaling can be inhibited by targeting MEK1/2; unfortunately, this approach has been largely ineffective in pancreatic cancer. Here, we set out to identify mechanisms of MEK inhibitor resistance in pancreatic cancer using primary mouse and human 3D organoid cultures. We optimized the culture of pancreatic tumor organoids that utilized Matrigel as a basement membrane mimetic, facilitating polarized growth. Pancreatic tumor organoids recapitulated mutant KRAS dependency and recalcitrance to MEK inhibition. Treatment of the organoids with trametinib, a MEK inhibitor, had only a modest effect on these cultures. We observed that cells adjacent to the basement membrane mimetic Matrigel survived MEK inhibition, while the cells in the interior layers underwent apoptosis. Our findings suggested that basement membrane attachment provided survival signals. We thus targeted integrin {beta}1, a mediator of extracellular matrix contact, and found that combined MEK and integrin {beta}1 inhibition bypassed trametinib resistance. Our data support exploring integrin signaling inhibition as a component of combination therapy in pancreatic cancer.

cancer biology↗