BLIMP-1 Plays Important Role in the Regulation of Macrophage Pyroptosis for the Growth and Multiplication of Leishmania donovani

G Saha, BM Khamar, K Prerna, M Kumar… - ACS infectious …, 2019 - ACS Publications
G Saha, BM Khamar, K Prerna, M Kumar, VK Dubey
ACS infectious diseases, 2019ACS Publications
Visceral leishmaniasis, one of the fatal forms of the disease, is caused by Leishmania
donovani and presents morbid clinical manifestations. The parasite evades pro-
inflammatory immune responses by several reported mechanisms and modulates the host
immune system to cause fatal symptoms. A plethora of reports related to the role of BLIMP-1
and its involvement in suppressing the immune response in various infectious diseases
have been documented. Higher parasitic burden due to increased BLIMP-1 production has …
Visceral leishmaniasis, one of the fatal forms of the disease, is caused by Leishmania donovani and presents morbid clinical manifestations. The parasite evades pro-inflammatory immune responses by several reported mechanisms and modulates the host immune system to cause fatal symptoms. A plethora of reports related to the role of BLIMP-1 and its involvement in suppressing the immune response in various infectious diseases have been documented. Higher parasitic burden due to increased BLIMP-1 production has been reported earlier for malaria and leishmaniasis with no detailed information. We report for the first time the role of BLIMP-1 in suppressing macrophage pyroptosis during L. donovani infection and thereby tweaking the tight regulation of the NFκβ–NLRP3 signaling pathway. Expression analyses of BLIMP-1 and NFκβ have been measured using real-time PCR and Western blotting. The importance of BLIMP-1 has been validated using a siRNA-mediated experiment along with caspase 1 activity, LDH release assay, and infectivity index analyses. An inverse relationship between BLIMP-1 and NFκβ expression has been highlighted during L. donovani infection, which is reversed in blimp-1 deficient cells infected with promastigotes. The above fact has been further validated with caspase 1 activity assay, and LDH release along with IFNγ and TNF-α release assay. Finally, resumption of pyroptosis has been concluded in infected blimp-1 deficient cells in contrast to wild type infected cells. We conjecture that parasites modulate the NFκβ–NLRP3 signaling pathway by taking advantage of BLIMP-1 dependent IL-10 production and finally disrupting an inflammation-mediated pyroptosis cell death pathway in infected cells.
ACS Publications