Mycobacterium avium subspecies paratuberculosis is able to manipulate host lipid metabolism and accumulate...

Area of Science:

• Veterinary Microbiology
• Cellular Biology
• Host-Pathogen Interactions

Background:

• Johne's disease, caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a chronic wasting illness in ruminants.
• Pathogenic mycobacteria, like M. tuberculosis, can alter host lipid metabolism, suggesting a similar role for MAP in its survival.
• Understanding MAP's interaction with host lipid pathways is key to explaining its intracellular persistence.

Purpose of the Study:

• To investigate if MAP manipulates host lipid metabolic pathways.
• To determine if MAP accumulates host cholesterol during the early stages of infection.
• To explore strain-specific differences in MAP's manipulation of host lipid metabolism.

Main Methods:

• Macrophages were infected with four MAP strains and a non-pathogenic M. phlei strain.
• Intracellular cholesterol levels were assessed using fluorescent microscopy.
• Host gene expression related to lipid metabolism and immune response was analyzed.

Main Results:

• MAP infection led to strain-dependent alterations in intracellular cholesterol during early infection.
• All MAP strains showed increased intracellular cholesterol at later infection timepoints.
• MAP upregulated host genes involved in lipid efflux and endocytosis, with differential regulation of lipid biosynthesis genes in a strain-dependent manner.

Conclusions:

• MAP actively manipulates host lipid metabolism and cholesterol accumulation during early infection.
• The extent of lipid metabolism modulation by MAP is strain-dependent.
• These findings highlight conserved mechanisms contributing to intracellular MAP survival.