Hypoxia Makes You Prone to Kala azar or Chronic Black Fever

Leishmaniasis or Kalazar or black fever is a disease caused by the parasite Leishmania donovani. It is spread by the bite of certain types of sandflies. Chronic infections also occur as the parasite uses a physiological response to lower oxygen levels, reveals a new study.

In an article in the latest issue of Plos Pathogens, INRS professor Simona St�ger and her team show how the parasite Leishmania donovani uses a physiological response to low oxygen levels (hypoxia) to establish a chronic infection.

‘The capacity of monocytes and macrophages to kill the parasite is reduced by the transcription factor HIF-1α, which plays a major role in the establishment of chronic Leishmania infections.’

The parasite behind visceral leishmaniasis causes a chronic inflammation that enlarges the spleen and creates a hypoxic microenvironment.

To compensate for the lack of oxygen and ensure their survival, cells adapt by inducing the expression of the transcription factor HIF-1α, the master regulator of the cellular response to hypoxia.

Professor St�ger and her team have demonstrated the effect of this key regulator on the function of monocytes and macrophages during viceral leishmaniasis, the most severe form of a tropical disease that affects millions of people around the world. These cells are the main targets of the parasite L. donovani.

"Our lab work demonstrates that HIF-1α plays a key role in the establishment of chronic Leishmania infections by reducing the capacity of monocytes and macrophages to kill the parasite. We also found that HIF-1α gives these cells immunosuppressant properties," explains Professor St�ger.



Source: Eurekalert