DIFFERENTIAL SUSCEPTIBILITY OF HUMAN SP-B GENETIC VARIANTS ON LUNG INJURY CAUSED BY BACTERIAL PNEUMONIA AND THE EFFECT OF A CHEMICALLY MODIFIED CURCUMIN

Shock. 2016 Apr;45(4):375-84. doi: 10.1097/SHK.0000000000000535.

Abstract

Staphylococcus aureus is a common cause of nosocomial pneumonia frequently resulting in acute respiratory distress syndrome (ARDS). Surfactant protein B (SP-B) gene expresses two proteins involved in lowering surface tension and host defense. Genotyping studies demonstrate a significant association between human SP-B genetic variants and ARDS. Curcumins have been shown to attenuate host inflammation in many sepsis models. Our hypothesis is that functional differences of SP-B variants and treatment with curcumin (CMC2.24) modulate lung injury in bacterial pneumonia. Humanized transgenic mice, expressing either SP-B T or C allele without mouse SP-B gene, were used. Bioluminescent labeled S. aureus Xen 36 (50 μL) was injected intratracheally to cause pneumonia. Infected mice received daily CMC2.24 (40 mg/kg) or vehicle alone by oral gavage. Dynamic changes of bacteria were monitored using in vivo imaging system. Histological, cellular, and molecular indices of lung injury were studied in infected mice 48 h after infection. In vivo imaging analysis revealed total flux (bacterial number) was higher in the lung of infected SP-B-C mice compared with infected SP-B-T mice (P < 0.05). Infected SP-B-C mice demonstrated increased mortality, lung injury, apoptosis, and NF-κB expression compared with infected SP-B-T mice. Compared with controls, CMC2.24 treatment significantly reduced the following: mortality, total bacterial flux and lung tissue apoptosis, inflammatory cells, NF-κB expression (P < 0.05), and MMPs-2, -9, -12 activities (P < 0.05). We conclude that mice with SP-B-C allele are more susceptible to S. aureus pneumonia than mice with SP-B-T allele, and that CMC2.24 attenuates lung injury thus reducing mortality.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Animals
  • Curcumin / pharmacology*
  • Genetic Predisposition to Disease*
  • Genetic Variation*
  • Humans
  • Lung Injury / drug therapy*
  • Lung Injury / genetics*
  • Lung Injury / metabolism
  • Mice
  • Mice, Transgenic
  • Pneumonia, Staphylococcal / drug therapy*
  • Pneumonia, Staphylococcal / genetics*
  • Pneumonia, Staphylococcal / metabolism
  • Pulmonary Surfactant-Associated Protein B / genetics*
  • Pulmonary Surfactant-Associated Protein B / metabolism
  • Staphylococcus aureus*

Substances

  • Pulmonary Surfactant-Associated Protein B
  • Curcumin