title: The Essential Role of Cholesterol Metabolism in the Intracellular Survival of Mycobacterium leprae Is Not Coupled to Central Carbon Metabolism and Energy Production.
abstract: Mycobacterium leprae induces the formation of lipid droplets, which are recruited to pathogen-containing phagosomes in infected macrophages and Schwann cells. Cholesterol is among the lipids with increased abundance in M. leprae-infected cells, and intracellular survival relies on cholesterol accumulation. The present study investigated the capacity of M. leprae to acquire and metabolize cholesterol. In silico analyses showed that oxidation of cholesterol to cholest-4-en-3-one (cholestenone), the first step of cholesterol degradation catalyzed by the enzyme 3β-hydroxysteroid dehydrogenase (3β-HSD), is apparently the only portion of the cholesterol catabolic pathway seen in Mycobacterium tuberculosis preserved by M. leprae. Incubation of bacteria with radiolabeled cholesterol confirmed the in silico predictions. Radiorespirometry and lipid analyses performed after incubating M. leprae with [4-(14)C]cholesterol or [26-(14)C]cholesterol showed the inability of this pathogen to metabolize the sterol rings or the side chain of cholesterol as a source of energy and carbon. However, the bacteria avidly incorporated cholesterol and, as expected, converted it to cholestenone both in vitro and in vivo. Our data indicate that M. leprae has lost the capacity to degrade and utilize cholesterol as a nutritional source but retains the enzyme responsible for its oxidation to cholestenone. Thus, the essential role of cholesterol metabolism in the intracellular survival of M. leprae is uncoupled from central carbon metabolism and energy production. Further elucidation of cholesterol metabolism in the host cell during M. leprae infection will establish the mechanism by which this lipid supports M. leprae intracellular survival and will open new avenues for novel leprosy therapies.
  
  
  OBJECTIVE
  Our study focused on the obligate intracellular pathogen Mycobacterium leprae and its capacity to metabolize cholesterol. The data make an important contribution for those interested in understanding the mechanisms of mycobacterial pathogenesis, since they indicate that the essential role of cholesterol for M. leprae intracellular survival does not rely on its utilization as a nutritional source. Our findings reinforce the complexity of cholesterol's role in sustaining M. leprae infection. Further elucidation of cholesterol metabolism in the host cell during M. leprae infection will establish the mechanism by which this lipid supports M. leprae intracellular survival and will open new avenues for novel leprosy therapies.
authors.affiliation: Laboratório de Microbiologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
authors.forename: Maria Angela M
authors.initials: MA
authors.lastname: Marques
authors.affiliation: Laboratório de Microbiologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Marcia
authors.initials: M
authors.lastname: Berrêdo-Pinho
authors.affiliation: Laboratório de Microbiologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Thabatta L S A
authors.initials: TL
authors.lastname: Rosa
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
authors.forename: Venugopal
authors.initials: V
authors.lastname: Pujari
authors.affiliation: Laboratório de Microbiologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Robertha M R
authors.initials: RM
authors.lastname: Lemes
authors.affiliation: Laboratório de Microbiologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Leticia M S
authors.initials: LM
authors.lastname: Lery
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
authors.forename: Carlos Adriano M
authors.initials: CA
authors.lastname: Silva
authors.affiliation: Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Ana Carolina R
authors.initials: AC
authors.lastname: Guimarães
authors.affiliation: Laboratório de Bioquímica de Lipídeos e Lipoproteínas, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Georgia C
authors.initials: GC
authors.lastname: Atella
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Wheat
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Brennan
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
authors.forename: Dean C
authors.initials: DC
authors.lastname: Crick
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Belisle
authors.affiliation: Laboratório de Microbiologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil cpessola@gmail.com.
authors.forename: Maria Cristina V
authors.initials: MC
authors.lastname: Pessolani
mesh_terms: D002244:Carbon / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism*; D004734:Energy Metabolism; D006801:Humans; D007918:Leprosy / Q000382:microbiology; D050296:Microbial Viability; D009166:Mycobacterium leprae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D002244:Carbon; D002784:Cholesterol