Effect of host fatty acid-binding protein and fatty acid uptake on growth of Chlamydia trachomatis L2

1 Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA 2 Faculty of Pharmacy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada 3 Faculty of Medicine, University of Manitoba, Winnipeg, MB R3T 2N2, Canada Correspondence Guangming Zhong Zhongg{at}UTHSCSA.edu Chlamydia trachomatis is an obligate intracellular bacterium and acquires both building blocks and energy from host cells for growth. The fatty acid-binding protein (FABP) plays an important role in uptake of long-chain fatty acids (LCFA) and energy metabolism by eukaryotic cells. The roles of FABP and LCFA in chlamydial infection were evaluated. Infection of liver cells with chlamydial organisms promoted fatty acid uptake by the infected cells, suggesting that LCFA may benefit chlamydial growth. Introduction of FABP into the liver cells not only enhanced fatty acid uptake, but also increased chlamydial intravacuolar replication and maturation. The FABP-enhanced chlamydial intracellular growth was dependent on the host cell uptake of fatty acids. These results have demonstrated that C. trachomatis can productively infect liver cells and utilize FABP-transported LCFA for its own biosynthesis. Abbreviations: DMEM, Dulbecco's modified Eagle's medium; EB, elementary body; FABP, fatty acid-binding protein; FBS, fetal bovine serum; IFU, inclusion-forming units; LCFA, long-chain fatty acids; LGV, lymphogranuloma venereum; RB, reticulate body