title: Mycobacterium tuberculosis expressing phospholipase C subverts PGE2 synthesis and induces necrosis in alveolar macrophages.
abstract: BACKGROUND
  Phospholipases C (PLCs) are virulence factors found in several bacteria. In Mycobacterium tuberculosis (Mtb) they exhibit cytotoxic effects on macrophages, but the mechanisms involved in PLC-induced cell death are not fully understood. It has been reported that induction of cell necrosis by virulent Mtb is coordinated by subversion of PGE2, an essential factor in cell membrane protection.
  
  
  RESULTS
  Using two Mtb clinical isolates carrying genetic variations in PLC genes, we show that the isolate 97-1505, which bears plcA and plcB genes, is more resistant to alveolar macrophage microbicidal activity than the isolate 97-1200, which has all PLC genes deleted. The isolate 97-1505 also induced higher rates of alveolar macrophage necrosis, and likewise inhibited COX-2 expression and PGE2 production. To address the direct effect of mycobacterial PLC on cell necrosis and PGE2 inhibition, both isolates were treated with PLC inhibitors prior to macrophage infection. Interestingly, inhibition of PLCs affected the ability of the isolate 97-1505 to induce necrosis, leading to cell death rates similar to those induced by the isolate 97-1200. Finally, PGE2 production by Mtb 97-1505-infected macrophages was restored to levels similar to those produced by 97-1200-infected cells.
  
  
  CONCLUSIONS
  Mycobacterium tuberculosis bearing PLCs genes induces alveolar macrophage necrosis, which is associated to subversion of PGE2 production.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Assis
authors.forename: Milena S
authors.initials: MS
authors.lastname: Espíndola
authors.forename: Francisco W G
authors.initials: FW
authors.lastname: Paula-Silva
authors.forename: Wendy M
authors.initials: WM
authors.lastname: Rios
authors.forename: Priscilla A T
authors.initials: PA
authors.lastname: Pereira
authors.forename: Sylvia C
authors.initials: SC
authors.lastname: Leão
authors.forename: Célio L
authors.initials: CL
authors.lastname: Silva
authors.affiliation: Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av Cafe, s/n, Ribeirão Preto, SP 14040-903, Brazil. faccioli@fcfrp.usp.br.
authors.forename: Lúcia H
authors.initials: LH
authors.lastname: Faccioli
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D016923:Cell Death; D015232:Dinoprostone / Q000037:antagonists & inhibitors*; D006801:Humans; D016676:Macrophages, Alveolar / Q000382:microbiology* / Q000502:physiology*; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000276:immunology / Q000302:isolation & purification; D014376:Tuberculosis / Q000382:microbiology; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; D010738:Type C Phospholipases; C101028:MpcA protein, Mycobacterium tuberculosis; C101029:MpcB protein, Mycobacterium tuberculosis; D015232:Dinoprostone