Biology subjects

Zanatta, J. M.

Publications and source records attributed to Zanatta, J. M..

3 recordsLinked to original sources

bioRxiv2026

microRNA-721 is a host regulator of TNF-IRF1 axis in Leishmania infected macrophage

MicroRNAs (miRNAs) are small noncoding RNAs that play critical roles in regulating immune responses and have emerged as potential biomarkers and therapeutic targets in complex diseases. Leishmaniasis is a neglected disease that compromises host immunity and is associated with challenging treatments regimens. Leishmania amazonensis (L. amazonensis), an intracellular protozoan parasite, causes cutaneous leishmaniasis by replicating inside mammalian macrophages to establish infection. In this context, miRNAs have emerged as vital post-transcriptional factors that regulate the inflammatory landscape during infection. In this study, we aimed to analyze the function of miR-721 in macrophages during L. amazonensis infection by integrating in silico miR-721 target prediction with RNAseq data from macrophages of two distinct mouse genotypes, resistant C57BL/6 and susceptible BALB/c. We found that miR-721 is induced in macrophages infected with L. amazonensis, but is not in LPS-stimulated macrophages, suggesting a TLR4-independent activation. Integrating miR-721 target prediction with comparative transcriptomic analyses in resistant C57BL/6 and susceptible BALB/c models revealed the TNF-IRF1 axis as a primary miR-721-associated regulatory network. Specifically, miR-721 is predicted to target the 3UTRs of Tnf and Irf1 to suppress the inflammatory response. Functional inhibition of miR-721 successfully restored Tnf and Irf1 expression and reduced the amastigote burden over 24 hours. Furthermore, we showed that the miR-721/TNF-IRF1 axis regulates downstream genes associated with macrophage response, such as Serpine1, Csf1, Cd69 and Maf. Our work demonstrated that Leishmania induces miR-721, which negatively modulates the TNF-IRF1 axis, thereby suppressing the immune response and favoring parasite persistence. While C57BL/6 macrophages exhibit a robust activation of the TNF-IRF1 network, promoting inflammatory response, BALB/c macrophage showed a breakdown of this network. This was associated with post-transcriptional suppression of inflammatory responses, thereby favoring parasite persistence. These findings link miR-721 to the establishment of macrophage polarization, providing relevant insights into the mechanisms of parasite subversion of the host immune response.

immunology↗

bioRxiv2026

Single-cell RNA sequencing of CTLA-4 and PD-1 blockade in pulmonary paracoccidioidomycosis highlights a protective transcriptional program mediated by activated Th17 cells, neutrophils and macrophages

Pulmonary paracoccidioidomycosis (PCM) relies on a finely balanced lung-immune network in which Th17, Treg, neutrophils, and macrophages orchestrate fungal control and tissue integrity. Furthermore, within the context of single-cell sequencing, little is known about how immune checkpoint inhibition modulates this balance during systemic mycosis. In a previous study we verified that the blockade of checkpoint molecules (CTLA-4 and PD-1) restores protective immunity that reduces fungal loads, tissue pathology and mortality of infected mice. Here, we have further studied this model by single-cell RNA sequencing on lung leukocytes from mice infected with Paracoccidioides brasiliensis and treated with anti-CTLA-4 or anti-PD-1 antibodies to define the cellular and molecular consequences of checkpoint blockade in vivo. We generated a high-resolution atlas covering T cells, neutrophils, macrophages/monocytes, B cells, NK cells, and epithelial subsets. Checkpoint inhibition consistently remodeled the CD4 T cell compartment toward a Th17-enriched program, with reduced interleukin-10 expressing Treg frequencies and a prominent interleukin-17A (IL-17), C-C chemokine receptor type 2, CXC chemokine (CXC) receptor type 6, CD44 (Il17aCcr2Cxcr6Cd44) signature. This shift was accompanied by the expansion and activation of neutrophils and macrophages expressing tumor necrosis factor and chemokines (including CXC motif chemokine ligand (Cxcl1, Cxcl2 and Ccl4), microbicidal-associated genes (S100 calcium-binding protein A8 and A9), and regulatory mediators such as secretory leukocyte protease inhibitor and interleukin-15. Ligand-receptor and trajectory analyses revealed a reinforced Th17-myeloid communication axis, particularly under CTLA-4 blockade, converging on IL17-centered inflammatory circuits while attenuating canonical Treg checkpoints (cytotoxic T-lymphocyte-associated protein 4, programmed cell death protein 1, interleukin-10). Together, these data demonstrate that anti-CTLA-4 and anti-PD-1 immunotherapies profoundly rewire the lung-immune microenvironment during PCM, amplifying effector Th17-neutrophil-macrophage networks that benefits protective antifungal activity Our work provides a mechanistic framework for evaluating immune checkpoint inhibitors in chronic fungal infections.

immunology↗

bioRxiv2022

Polyamines shift expression of macrophage L-arginine metabolism related-genes during Leishmania amazonensis infection

Polyamines are molecules involved in macrophage activation and polarization in response to pathogens. The interaction with Leishmania promotes modulation of macrophage immune response to favor arginine deviation to polyamines production, leading to parasite survival. Polyamine levels are a potential modulator of growth factors, driving cells to proliferation, wound healing, oxidative stress, or regulating translation. Here, we investigate the impact of L-arginine and polyamines in the transcriptional regulation of genes involved in arginine metabolization and pro-inflammatory response to L. amazonensis in murine BALB/c macrophages. We found that supplementation with L-arginine is insufficient to modulate macrophage gene expression and infection. Polyamine supplementation altered nitric oxide synthase (Nos2) and nitric oxide (NO) production, as well as other macrophage enzymes. Putrescine supplementation increased transcript levels of polyamine metabolism-related genes Arginase 2 (Arg2), Spermidine synthase (SpdS), and Spermine synthase (SpmS) in both uninfected and L. amazonensis infected macrophages. Putrescine increased Nos2 expression without leading to NO production, while L-arginine plus spermine led to production of NO in uninfected macrophages. Besides, L-arginine supplementation reduced the levels of Il-1b during infection, and L-arginine or L-arginine plus putrescine increased Mcp1 at 24h of infection. The percentage of infected macrophages was lower after putrescine, spermidine, and spermine supplementation than L-arginine supplementation. Our data showed that the polyamines shift L-arginine-metabolism related-genes on BALB/c macrophages and affect infection by L. amazonensis.

molecular biology↗