title: Chlamydia trachomatis growth and development requires the activity of host Long-chain Acyl-CoA Synthetases (ACSLs).
abstract: The obligate-intracellular pathogen Chlamydia trachomatis (Ct) has undergone considerable genome reduction with consequent dependence on host biosynthetic pathways, metabolites and enzymes. Long-chain acyl-CoA synthetases (ACSLs) are key host-cell enzymes that convert fatty acids (FA) into acyl-CoA for use in metabolic pathways. Here, we show that the complete host ACSL family [ACSL1 and ACSL3-6] translocates into the Ct membrane-bound vacuole, termed inclusion, and remains associated with membranes of metabolically active forms of Ct throughout development. We discovered that three different pharmacologic inhibitors of ACSL activity independently impede Ct growth in a dose-dependent fashion. Using an FA competition assay, host ACSLs were found to activate Ct branched-chain FAs, suggesting that one function of the ACSLs is to activate Ct FAs and host FAs (recruited from the cytoplasm) within the inclusion. Because the ACSL inhibitors can deplete lipid droplets (LD), we used a cell line where LD synthesis was switched off to evaluate whether LD deficiency affects Ct growth. In these cells, we found no effect on growth or on translocation of ACSLs into the inclusion. Our findings support an essential role for ACSL activation of host-cell and bacterial FAs within the inclusion to promote Ct growth and development, independent of LDs.
authors.affiliation: Center for Immunobiology and Vaccine Development, UCSF Benioff Children's Hospital Oakland Research Institute, Oakland, CA, 94609, USA.|Department of Infectious Disease, Johns Hopkins University, Baltimore, MD, 21205, USA.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Recuero-Checa
authors.affiliation: Center for Immunobiology and Vaccine Development, UCSF Benioff Children's Hospital Oakland Research Institute, Oakland, CA, 94609, USA.
authors.forename: Manu
authors.initials: M
authors.lastname: Sharma
authors.affiliation: Center for Immunobiology and Vaccine Development, UCSF Benioff Children's Hospital Oakland Research Institute, Oakland, CA, 94609, USA.
authors.forename: Constance
authors.initials: C
authors.lastname: Lau
authors.affiliation: Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD, 21205, USA.|Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Watkins
authors.affiliation: Department of Infectious Disease, Johns Hopkins University, Baltimore, MD, 21205, USA.
authors.forename: Charlotte A
authors.initials: CA
authors.lastname: Gaydos
authors.affiliation: Center for Immunobiology and Vaccine Development, UCSF Benioff Children's Hospital Oakland Research Institute, Oakland, CA, 94609, USA.|Department of Bioengineering, University of California at Berkeley and San Francisco, CA, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Dean
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002692:Chlamydia trachomatis / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D003066:Coenzyme A Ligases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000378:metabolism; D006367:HeLa Cells; D056945:Hep G2 Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D021381:Protein Transport / Q000187:drug effects; D014617:Vacuoles / Q000378:metabolism*; D000098859:Long-Chain-Fatty-Acid-CoA Ligase
chemical_list: D000900:Anti-Bacterial Agents; D005227:Fatty Acids; D003066:Coenzyme A Ligases; C583414:ACSL1 protein, human; C485465:ACSL5 protein, human; C403665:ACSL6 protein, human; D000098859:Long-Chain-Fatty-Acid-CoA Ligase