A Cationic Amphiphilic Drug (CAD) Defense System in the Nematode Caenorhabditis elegans

Sep 29, 2026

Cationic amphiphilic drugs (CADs) disrupt lysosomal function and cause acellular pathology characterized by excess phospholipids, termed phospholipidosis. Using a forward genetic screen and analysis of published datasets, the study finds that CADs activate CYP-35B family cytochrome P450s and PGP-13 via nuclear receptors NHR-70 and NHR-107 in Caenorhabditis elegans. A pgp-13 fluorescent reporter identifies many human drugs that upregulate this defense in vivo. Chemoinformatic and metabolomics-driven mutant analyses show CYP-35Bs are required and sufficient for CAD metabolism, with CYP-35B2 D311 critical for electrostatic interactions. CAD metabolites are exported via PGP-13 with partial redundancy from PGP-14, and an intact defense system protects against CAD-induced pathology. The work also suggests bacteria cohabiting with C. elegans can trigger the pathway.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages75

Reading Time3 h 9 min

AccessFree to download

Abstract

Introduction

bioRxiivv preprriiintinntt doii:: https::////ddooiii.org//1100.64898/2026.01.03.697488; thiisiiss versiiiionoonn posted Januarryy 3 , 2026.. The copyrriiiightgghhttt holllderlddeerr for thiiss preprintreprintrint (whichwhiicchh was not certiiffiiedieedd by peer rrreview)eviieeww))) isiis the author/funder,, who has grantedranted biioRxiioRxivoRxiiiivvv a llliiiicceennssee to diiisplayisspplayllaayy the preprintrint iniiiiinn perpettuuiittyy. ItIIt iisis made avaiilableillaabbllleee under aCC-BY-NC-ND 4.00 IInternationalInternatiioonnaalll liiicenseiiicceennssee. A Cationic Amphiphilic Drug (CAD) Defense System in the Nematode Caenorhabditis elegans Levon Tokmakjian1,2, Duhyun Han1,2, Kateryna Sihuta2,3, Aanchal Aggarwal2,3, Somayeh Pirhadi4, Yao Wang4, Andrew R. Burns2,3, Brittany Cooke2,3, Siyue Ren1,2, Carolyn L. Cummins5, Justin Nodwell6, David R. Koes4, and Peter J. Roy1,2,3,7 1. Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada 2. The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada 3. Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada 4. Department of Computational and Systems Biology, University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, Pennsylvania 15260, United States. 5. Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada 6. Department of Biochemistry, University of Toronto, 1 King’s College Circle, Toronto, ON, M5S 1A8, Canada 7Corresponding Author: Peter J. Roy Tel: (416) 946-8395 bioRxiv preprint doi: [https://doi.org/10.64898/2026.01.03.697488](https://doi.org/10.64898/2026.01.03.697488); this version posted January 3, 2026. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Abstract Cationic Amphiphilic Drugs (CADs) severely disrupt lysosomal function, which leads to acellular pathology characterized by excess phospholipids called phospholipidosis. Through a forward genetic screen and mining of published datasets, we discovered that CADs induce the expression of the CYP-35B family of cytochrome P450s and the PGP-13 p-glycoprotein pump via the nuclear receptors NHR-70 and NHR-107 in the nematode C. elegans. A pgp-13 fluorescent reporter revealed hundreds of human drugs that upregulate the CAD defense system in vivo. Chemoinformatic analyses indicate that the pgp-13 reporter may be useful in identifying CADs that have pathogenic potential in humans. Mutant analyses coupled to metabolomics and structural modeling show that the CYP-35Bs are necessary and sufficient for CAD metabolism, and that CYP-35B2 D311 is key in mediating electrostatic interactions with the positively charged CADs. We also show that CAD metabolites are effluxed via PGP-13 acting partially redundantly with PGP-14 and that an intact defense system is necessary to resist CAD-induced pathology. Finally, we demonstrate that bacteria that likely cohabitate with C. elegans in nature trigger the CAD defense system, providing a plausible explanation for why a pathway that protects against anthropogenic small molecules exists in nematodes. bioRxiv preprint doi: [https://doi.org/10.64898/2026.01.03.697488](https://doi.org/10.64898/2026.01.03.697488); this version posted January 3, 2026. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Introduction Cationic Amphiphilic Drugs (CADs) can severely disrupt lysosomal function and lead to acellular pathology called drug-induced phospholipidosis (PLD) (BREIDEN AND SANDHOFF 2019) .

FAQs

How do CADs lead to pathology in Caenorhabditis elegans?

CADs severely disrupt lysosomal function, producing acellular pathology characterized by excess phospholipids called phospholipidosis.

Which genes and regulatory factors control the CAD defense system?

CADs induce expression of the CYP-35B cytochrome P450 family and the PGP-13 p-glycoprotein pump through nuclear receptors NHR-70 and NHR-107.

How can the pathway be monitored and what does the pgp-13 reporter reveal?

A pgp-13 fluorescent reporter reveals hundreds of human drugs that upregulate the CAD defense system in vivo, suggesting potential pathogenicity in humans.

Sep 29, 2026

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