Biology subjects

Revtovich, A. V.

Publications and source records attributed to Revtovich, A. V..

5 recordsLinked to original sources

bioRxiv2026

P. aeruginosa liquid-based pathogenesis triggers HLH-30-dependent metabolic rewiring in C. elegans

Innate immunity is the first line of defense against invading pathogens and is essential for maintaining host survival. While the majority of innate immunity studies have focused on pathogen recognition and antimicrobial responses, increasing evidence suggests that lipid metabolism plays a fundamental role in shaping immune function. Understanding how these metabolic pathways contribute to immunity is crucial in the context of bacterial infections caused by opportunistic pathogens such as Pseudomonas aeruginosa. Host defense against P. aeruginosa requires the coordination of innate immune and metabolic responses; however, the mechanisms linking lipid metabolism to pathogen resistance remain poorly understood. Research into the relationship between lipid homeostasis and innate immunity may reveal factors governing host-pathogen interactions and identify novel strategies to enhance resistance to infection. Here, we demonstrate that P. aeruginosa liquid-based pathogenesis (LK-Pa) triggers a shift in host metabolism which differs from the one observed in response to agar-based pathogenesis. Our bioinformatic analyses revealed a highly similar metabolic profile (enrichment of lipid metabolism) in worms exposed to LK-Pa or the iron chelator phenanthroline, suggesting a shared host response to iron deprivation. We further characterized the host genetic factors driving this metabolic shift and established their importance for host defense against LK-Pa as well as liquid-based pathogenesis by Gram-positive pathogens Enterococcus faecalis and Staphylococcus aureus. Notably, our results indicate that LK-Pa triggers host lipid droplet depletion, an upstream component that leads to increased {beta}-oxidation. Finally, we demonstrate that LK-Pa triggers repression of MXL-3 which results in HLH-30-dependent metabolic rewiring.

cell biology↗

bioRxiv2025

Cheminformatic identification of small molecules targeting acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive hematological malignancy with poor prognosis and high relapse rates when treated with cytotoxic chemotherapeutics. Previously, we identified a family of small molecules that modulate mitochondrial function, referred to as PS127-family compounds. These drugs were selectively toxic to AML and were characterized by two predicted functions: apoptotic agonism and thioredoxin/glutathione reductase inhibition. Here, we uncovered a third critical predicted function, autophagic induction. Using a cheminformatic screen of [~]4.2 million compounds for molecules with high predicted probability for all three functions, we found and validated hits that selectively killed AML cells, activated apoptosis, were dependent upon autophagic activation, and compromised glutathione metabolism by interfering with glutathione reductase, all of which are consistent with predictions. Compound treatment increased pools of cytosolic and mitochondrial ROS, decreased oxygen consumption, and reduced ATP synthesis. Structurally-unrelated compounds caused the same phenotypes, validating our approach of screening for predicted function. Finally, we also observed strong synergy between these compounds and midostaurin and venetoclax, underscoring their therapeutic potential. Key phenotypes, including the compounds impact on glutathione metabolism and synergy with doxorubicin and midostaurin, were confirmed in AML-patient-derived primary cells, validating the potential of these compounds for the development of future AML treatments.

cancer biology↗

bioRxiv2021

Small Molecule Stabilization of PINK-1/PINK1 Improves Neurodegenerative Disease

Macroautophagic recycling of dysfunctional mitochondria, known as mitophagy, is essential for mitochondrial homeostasis and cell viability. Accumulation of defective mitochondria and impaired mitophagy have been widely implicated in many neurodegenerative diseases, and loss-of-function mutations of two regulators of mitophagy, PINK1 and Parkin, are amongst the most common causes of recessive Parkinsons disease. Activation of mitophagy via pharmacological treatments may be a feasible approach for combating neurodegeneration. In this effort, we screened [~]45,000 small molecules for the ability to activate mitophagy. A high-throughput, whole-organism, phenotypic screen was conducted by monitoring stabilization of PINK-1/PINK1, a key event in mitophagy activation, in a Caenorhabditis elegans strain carrying a Ppink-1::PINK-1::GFP reporter. We obtained eight hits that induced mitophagy, as evidenced by increased mitochondrial fragmentation and autophagosome formation. Several of the compounds also reduced ATP production, oxygen consumption, mitochondrial mass, and/or mitochondrial membrane potential. Importantly, we found that treatment with two compounds, which we named PS83 and PS106 (more commonly known as sertraline) reduced neurodegenerative disease phenotypes (including delayed paralysis in a C. elegans Alzheimers model) in a PINK-1/PINK1-dependent manner. This report presents a promising step toward the identification of compounds that will stimulate mitochondrial turnover.

cell biology↗

bioRxiv2020

Novel Immune Modulators Enhance Caenorhabditis elegans Resistance to Multiple Pathogens

Traditionally, treatments for bacterial infection have focused on killing the microbe or preventing its growth. As antimicrobial resistance becomes more ubiquitous, the feasibility of this approach is beginning to wane and attention has begun to shift toward disrupting the host-pathogen interaction by improving the host defense. Using a high-throughput, fragment-based screen to identify compounds that alleviate Pseudomonas aeruginosa-mediated killing of Caenorhabditis elegans, we identified over 20 compounds that stimulated host defense gene expression. Five of these molecules were selected for further characterization. Four of five compounds showed little toxicity against mammalian cells or worms, consistent with their identification in a phenotypic, high-content screen. Each of the compounds activated several host defense pathways, but the pathways were generally dispensable for compound-mediated rescue in Liquid Killing, suggesting redundancy or that the activation of one or more unknown pathways may be driving compound effects. A genetic mechanism was identified for LK56, which required the Mediator subunit MDT-15/MED15 and NHR-49/HNF4 for its function. Interestingly, LK32, LK34, LK38, and LK56 also rescue C. elegans from P. aeruginosa in an agar-based assay, which uses different virulence factors and defense mechanisms. Rescue in an agar-based assay for LK38 entirely depended upon the PMK-1/p38 MAPK pathway. Three compounds, LK32, LK34, and LK56 also conferred resistance to Enterococcus faecalis, and the two lattermost, LK34 and LK56, also reduced pathogenesis from Staphylococcus aureus. This study supports a growing role for MDT-15 and NHR-49 in immune response and identifies 5 molecules that with significant potential for use as tools in the investigation of innate immunity. Author SummaryTwo trends moving in opposite directions (the increase in antimicrobial resistance and the decline of commercial interest in the discovery and development of novel antimicrobials) have precipitated a looming crisis: a nearly complete inability to safely and effectively treat bacterial infections. To avert this, new approaches in healthcare are needed. One approach that is receiving increasing attention is to stimulate host defense pathways, to improve the clearance of bacterial infections. We describe five small molecules that promote host resistance to infectious bacteria, at least partially by activating C. elegans innate immune pathways. Several are effective against both Gram-positive and Gram-negative pathogens. Three molecules, LK34, LK35, and LK38 have highly overlapping downstream target genes, suggesting that they act on common pathways, despite having distinct chemical structures. One of the compounds was mapped to the action of MDT-15/MED15 and NHR-49/HNF4, a pair of transcriptional regulators more generally associated with fatty acid metabolism, potentially highlighting a new link between these biological functions. These studies pave the way for future characterization of the anti-infective activity of the molecules in higher organisms and highlight the compounds potential utility for further investigation of immune modulation as a novel therapeutic approach.

genetics↗

bioRxiv2020

Systematic characterization and genetic interaction analysis of adhesins in Candida albicans virulence

Candida albicans is a microbial fungus that exists as a commensal member of the human microbiome and an opportunistic pathogen. Cell surface-associated adhesin proteins play a crucial role in C. albicans ability to undergo cellular morphogenesis, develop robust biofilms, colonize, and cause infection in a host. However, a comprehensive analysis of the role and relationships between these adhesins has not been explored. We previously established a CRISPR-based platform for efficient generation of single- and double-gene deletions in C. albicans, which was used to construct a library of 144 mutants, comprising 12 unique adhesin genes deleted singly, or in every possible combination of double deletions. Here, we exploit this adhesin mutant library to explore the role of adhesin proteins in C. albicans virulence. We perform a comprehensive, high-throughput screen of this library, using Caenorhabditis elegans as a simplified model host system, which identified mutants critical for virulence and significant genetic interactions. We perform follow-up analysis to assess the ability of high- and low-virulence strains to undergo cellular morphogenesis and form biofilms in vitro, as well as to colonize the C. elegans host. We further perform genetic interaction analysis to identify novel significant negative genetic interactions between adhesin mutants, whereby combinatorial perturbation of these genes significantly impairs virulence, more than expected based on virulence of the single mutant constituent strains. Together, this yields important new insight into the role of adhesins, singly and in combinations, in mediating diverse facets of virulence of this critical fungal pathogen. SummaryCandida albicans is a human fungal pathogen and cause of life-threatening systemic infections. Cell surface-associated adhesins play a central role in this pathogens ability to establish infection. Here, we provide a comprehensive analysis of adhesin factors, and their role in fungal virulence. Exploiting a high-throughput workflow, we screened an adhesin mutant library using C. elegans as a simple model host, and identified mutants and genetic interactions involved in virulence. We found that adhesin mutants are impaired in in vitro pathogenicity, irrespective of their virulence. Together, this work provides new insight into the role of adhesin factors in mediating fungal virulence.

microbiology↗