Lyme Disease Bacteria Has Odd Quirk Never Before Seen In Any Other Organism

Scientists have discovered that the pathogen that causes Lyme disease can exist without iron by depending on manganese, a characteristic unknown in any other organism, according to a new study.

Iron is used by all other life forms to make proteins and enzymes. Instead of iron, the Lyme disease bacteria Borrelia burgdorferi substitutes manganese to make an essential enzyme, enabling the bacteria to elude immune system defense mechanisms that protect the body by starving pathogens of iron.

Lyme disease is the most common tick-born disease in the Northern hemisphere. Ticks carrying the Borrelia pathogen can transmit the disease to humans through a bite. Caught early, Lyme disese can treated with antibiotics; the disease can be debilitative in later stages.   

The findings by a multi-institutional team of researchers may shed some light on the mysteries surrounding the hard to detect and difficult to treat disease.

The findings also open a door for researchers to look into new opportunities to develop Lyme disease treatments by targeting manganese.

"When we become infected with pathogens, from tuberculosis to yeast infections, the body has natural immunological responses," said Valeria Culotta, a molecular biologist at the Johns Hopkins University Bloomberg School of Public Health. "The liver produces hepcidin, a hormone that inhibits iron from being absorbed in the gut and also prevents it from getting into the bloodstream. We become anemic, which is one reason we feel terrible, but it effectively starves pathogens of iron they need to grow and survive," she said.

The Borrelia bacteria can evade the body's defenses because it does not need iron, something that was revealed by groundbreaking research in 2000. Culotta's team sought to determine what Borrelia used to work around an organism's need for iron.

To find out, Culotta teamed up with Mak Saito, a marine chemist at Woods Hole Oceanographic Institution, who had researched how marine life uses metals like iron.

The team found that Borrelia can use manganese to build amino peptidase and an important antioxidant enzyme called superoxide dismutase

The finding may help in the development of effective treaments for Lyme disease.

"We'd like to find targets inside pathogenic cell that could thwart their growth," said Culotta. "The best targets are enzymes that the pathogens have, but people do not, so they would kill the pathogens but not harm people." 

Borrelia's distinctive manganese-containing enzymes such as superoxide dismutase may have such attributes, the study stated. 

The study is published in the Journal of Biological Chemistry.