PARP1-cGAS-NF-κB pathway of proinflammatory macrophage activation by extracellular vesicles released during Trypanosoma cruzi infection and Chagas disease

Abstract

Trypanosoma cruzi (T. cruzi) is the etiological agent of Chagas cardiomyopathy. In the present study, we investigated the role of extracellular vesicles (Ev) in shaping the macrophage (Mφ) response in progressive Chagas disease (CD). We purified T. cruzi Ev (TcEv) from axenic parasite cultures, and T. cruzi-induced Ev (TEv) from the supernatants of infected cells and plasma of acutely and chronically infected wild-type and Parp1-/mice. Cultured (Raw 264.7) and bone-marrow Mφ responded to TcEV and TEv with a profound increase in the expression and release of TNF-α, IL-6, and IL-1β cytokines. TEv produced by both immune (Mφ) and non-immune (muscle) cells were proinflammatory. Chemical inhibition or genetic deletion of PARP1 (a DNA repair enzyme) significantly depressed the TEv-induced transcriptional and translational activation of proinflammatory Mφ response. Oxidized DNA encapsulated by TEv was necessary for PARP1-dependent proinflammatory Mφ response. Inhibition studies suggested that DNA-sensing innate immune receptors (cGAS>>TLR9) synergized with PARP1 in signaling the NFκB activation, and inhibition of PARP1 and cGAS resulted in >80% inhibition of TEv-induced NFκB activity. Histochemical studies showed intense inflammatory infiltrate associated with profound increase in CD11b + CD68 + TNF-α + Mφ in the myocardium of CD wild-type mice. In comparison, chronically infected Parp1-/mice exhibited low-to-moderate tissue inflammation, >80% decline in myocardial infiltration of TNF-α + Mφ, and no change in immunoregulatory IL-10 + Mφ. We conclude that oxidized DNA released with TEv signal the PARP1-cGAS-NF-κB pathway of proinflammatory Mφ activation and worsens the chronic inflammatory pathology in CD. Small molecule antagonists of PARP1-cGAS signaling pathway would potentially be useful in reprogramming the Mφ activation and controlling the chronic inflammation in CD.

Trypanosoma cruzi Induces the PARP1/AP-1 Pathway for Upregulation of Metalloproteinases and Transforming Growth Factor β in Macrophages: Role in Cardiac Fibroblast Differentiation and Fibrosis in Chagas Disease

“…Further, we have found that T. cruzi infection and chronic CD induce release of extracellular vesicles (EV) carrying oxidized DNA of host and parasite origin. When phagocytized by M, the oxidized DNA in these EV was sensed by the cytosolic DNA response element cGAS, which synergized with PARP1 to signal NF-B transcriptional activation (12). Our results in this study show that T. cruzi-induced EV (TEV) were not profibrotic, and invasion by live T. cruzi was required to induce the MMP/TGF-␤ expression in M. These findings suggest that TEV do not regulate the MMP and TGF-␤ expression in M by the involvement of cytosolic cGAS-PARP1 and the downstream NF-B signaling pathway.…”

“…Data are representative of two independent experiments (three biological replicates per treatment and duplicate observations per sample) and are means and SD.^, P Յ 0.05; ϩϩϩ and^^^, P Յ 0.001 (ϩ, noninfected versus infected by Student's two-tailed t test or nonparametric Mann-Whitney U test;^, infected versus infected/treated by one-way ANOVA and Tukey's post hoc test). mediated proinflammatory gene expression in cardiac myocytes and M in response to T. cruzi infection (12,21) and in M stimulated with extracellular vesicles (EV) released by infected cells (12). Since NF-B can be involved in transcription of metalloproteinases, we determined if PARP1 also signals profibrotic gene expression during T. cruzi infection.…”

Perils and Promises of Pathogenic Protozoan Extracellular Vesicles

“…Also, the inoculation of T. cruzi -derived EVs following T. cruzi infection resulted in the induction of high levels of TNF-α, interferon gamma (IFN-γ), monocyte chemoattractant protein-1 (MCP-1), and IL-6 cytokines (Lovo-Martins et al, 2018 ). T. cruzi trypomastigote-derived EVs elicited increase in TNF-α and IL-6 release in bone-marrow macrophage response (Choudhuri and Garg, 2020 ). This establishes the concept that a protozoan parasite and its derived EVs may work in tandem to establish infection.…”

The cGAS-STING Pathway in Hematopoiesis and Its Physiopathological Significance

“…The cGAS-STING pathway protects against infections with viruses, bacteria, and protozoan parasites by sensing pathogenic DNA, infection-induced mitochondrial damage, bacterial proteins, virulence factors and metabolites, and bacteria-derived cyclic dinucleotides (CDNs) (79)(80)(81)(82)(83)(84). Meanwhile, infected cells transactivate the cGAS-STING pathway in bystander cells via the cell-to-cell transmission of cGAMP or the release of extracellular vesicles (EVs) (85)(86)(87)(88)(89). Based on accumulating evidence, HSPCs, and not only their progeny immune cells, are able to directly sense and respond to infections.…”