Taylon F. Silva

Conference 2022 Live Talk

 

Talk title

Hyperglycemic environment promotes M2 polarization in macrophages during Leishmania infection and impairs antigen presentation and T cell activation

 

Authors and Affiliations

Taylon Felipe Silva1, Virginia Márcia Concato1, Mariana Barbosa Detoni1, Fernanda Tomiotto-Pellissier2, Manoela Daiele Gonçalves1, Bruna Taciane da Silva Bortoleti1, Ellen Mayara Souza Cruz1, Milena Menegazzo Miranda-Sapla1, Idessânia Nazareth Costa1, Danielle Lazarin Bidoia1, Wander Rogério Pavanelli1, Ivete Conchon-Costa1.

1. Department Pathological Sciences, Universidade Estadual de Londrina, Paraná, Brazil.
2. Department of Medical Pathology, Universidade Federal do Paraná, Paraná, Brazil.

 

Abstract

Background

Leishmaniasis is an infectious disease characterized by chronic inflammation resulting from the parasite’s ability to immunomodulate and is highly endemic worldwide. Diabetes is a chronic disease resulting from insulin dysfunction leading to a state of chronic hyperglycemia that triggers low-grade inflammation and immune compromise. Thus, this work aimed to investigate the changes triggered by a hyperglycemic environment in macrophages exposed to Leishmania Leishmania amazonensis (LLa) infection.

Methods

THP-1-derived macrophages were cultured in hyperglycemic or normal médium for 7 days and infected with LLa for 2 to 72h. Infection index was analyzed by qPCR and flow cytometry. Oxidative stress and antioxidante enzymes were evaluated by fluorimetric and colorimetric assays. Immunophenotyping was performed in a flw cytometer by labeling proteins from the M1 and M2 macrophage patterns. For antigen presentation assay, peritoneal macrophages from healthy or streptozotocin-induced diabetes mice were collected and infected for 48 h com LLa, followed by co-culture with CFSE-labeled autologous spleenic T cells. Antigen presentation was assessed lymphocyte proliferation and IFN-γ production.

Results

HG macrophages showed twice the parasite load after 48 and 72 h of infection compared to control. Also, the recovery of viable internalized parasites after 48h of infection was shown to be 3.5 times lower in the control group than in the HG. After infection, the control group significantly increased the production and reactive species of oxygen, superoxide anion and lytic enzymes like NAG, which did not occur in the HG group. On the other hand, HG group increases activity of SOD and catalase, two enzymes responsible for scavenging free radicals. Additionally, control group showed an M1 macrophage phenotype, with increased expression of HLA-DR, CD80 and CD86 receptors, while HG showed an M2 phenotype with increased arginase and CD206 after infection. In addition, using a murine model we observed that macrophages from diabetic mice fail to present LLa antigens and induce T cell proliferation and production of IFN-γ when compared to macrophages from healthy mice.

Conclusions

Macrophages exposed to a hyperglycemic environment become more susceptible to LLa infection, lose their capacity to generate oxidative stress in the face of infection, and differentiate into an M2 phenotype, incapable of presenting antigens and activating T lymphocyte proliferation.