Leishmania-Induced Inactivation of the Macrophage Transcription Factor AP-1 Is Mediated by the Parasite Metalloprotease GP63

Abstract

Leishmania parasites have evolved sophisticated mechanisms to subvert macrophage immune responses by altering the host cell signal transduction machinery, including inhibition of JAK/STAT signalling and other transcription factors such as AP-1, CREB and NF-κB. AP-1 regulates pro-inflammatory cytokines, chemokines and nitric oxide production. Herein we show that upon Leishmania infection, AP-1 activity within host cells is abolished and correlates with lower expression of 5 of the 7 AP-1 subunits. Of interest, c-Jun, the central component of AP-1, is cleaved by Leishmania. Furthermore, the cleavage of c-Jun is dependent on the expression and activity of the major Leishmania surface protease GP63. Immunoprecipitation of c-Jun from nuclear extracts showed that GP63 interacts, and cleaves c-Jun at the perinuclear area shortly after infection. Phagocytosis inhibition by cytochalasin D did not block c-Jun down-regulation, suggesting that internalization of the parasite might not be necessary to deliver GP63 molecules inside the host cell. This observation was corroborated by the maintenance of c-Jun cleavage upon incubation with L. mexicana culture supernatant, suggesting that secreted, soluble GP63 could use a phagocytosis-independent mechanism to enter the host cell. In support of this, disruption of macrophage lipid raft microdomains by Methyl β-Cyclodextrin (MβCD) partially inhibits the degradation of full length c-Jun. Together our results indicate a novel role of the surface protease GP63 in the Leishmania-mediated subversion of host AP-1 activity.

Antimony-resistant but not antimony-sensitiveLeishmania donovaniup-regulates host IL-10 to overexpress multidrug-resistant protein 1

“…Activation of c-Fos and c-Jun to drive MDR1 overproduction in Sb R LD-infected Mϕs seems unique. Indeed, it has been reported previously that in different species of Leishmania, including LD, surface metalloprotease gp63 inactivates all the subunits of the AP-1 transcription factor, because all the subunits, such as c-Fos, c-Jun, Jun B, Jun D, and Fra 1, have putative sites of gp63 cleavage (32). The contrast, compared with our findings, could be explained by experimental differences between the two studies.…”

“…Previous reports suggested that activation of ERK is the key step for IL-10 induction (31). Interestingly, infection with Sb S LD results in the inactivation of host ERK, NF-κB, and JNK, thereby favoring establishment of the parasite (32). In our study, we also did not observe any activation of ERK or NF-κB in Mϕs infected with Sb S LD, although Sb R LD activates ERK and nuclear translocation of NF-κB involving p50/c-Rel, leading to IL-10 induction, through interaction with IL-10 promoter site II (−583/ −593).…”

Proteomic-Based Approach To Gain Insight into Reprogramming of THP-1 Cells Exposed to Leishmania donovani over an Early Temporal Window

“…SHP-1 reversibly associates with the IFN-␣ receptor complex upon IFN stimulation and selectively inhibits the JAK/STAT signaling pathway (3). SHP-1 is also known to have an inhibitory effect on JAK2, the Erk1/Erk2 MAPK, NF-B, IRF-1, and AP-1, which in turn inhibit IFN-␥-inducible macrophage function (5,52). The pattern of abundance of SHP-1 was observed in two of the replicate experiments and was identified based on a single peptide in the proteomic screen.…”

Wnt5a Signaling Promotes Host Defense againstLeishmania donovaniInfection

“…A decrease in Wnt5a protein upon L. donovani promastigote infection could be due to the activity of L. donovani proteases, such as GP63. This concept arises from the observed inhibition of the diminution of Wnt5a levels of infected cells through administration of phenanthroline, an inhibitor of GP63-like protease activity (31) (Fig. 1E).…”