The expression of TLR2 and TLR4 in the kidneys and heart of mice infected with Acanthamoeba spp.

Abstract

Background Acanthamoeba spp. are cosmopolitan protozoans that cause infections in the brain, as well as extracerebral infections in the cornea, lungs and skin. Little is known about the mechanisms of the immunological response to these parasites in organs which are not their main biotope. Therefore, the purpose of this study was to determine the expression of TLR2 and TLR4 in the kidneys and heart of Acanthamoeba spp.-infected mice, with respect to the host’s immunological status. Methods The mice were grouped into four groups: immunocompetent control mice; immunosuppressed control mice; immunocompetent Acanthamoeba spp.-infected mice; and immunosuppressed Acanthamoeba spp. infected mice. In the study, we used the amoebae T16 genotype which was isolated from a patient. The TLRs expressions in the kidneys and heart of mice were assessed by quantitative real-time polymerase chain reaction. Moreover, we visualized TLR2 and TLR4 proteins in the organs by immunohistochemical staining. Results In the kidneys, we observed a higher TLR2 expression in immunosuppressed mice at 24 days post-Acanthamoeba spp. infection (dpi) compared to the uninfected mice. There were no statistically significant differences in TLR4 expression in the kidneys between the immunocompetent and immunosuppressed mice, both of infected and uninfected mice. In the heart, we observed a difference in TLR2 expression in immunocompetent mice at 24 dpi compared to immunocompetent mice at 8 dpi. The immunocompetent Acanthamoeba spp.-infected mice had higher TLR4 expression at 8 dpi compared to the immunocompetent uninfected mice. Conclusions Our results indicate that TLR2 is involved in response to Acanthamoeba spp. infection in the kidneys, whereas in the heart, both studied TLRs are involved.

Potential Biomarkers in Diagnosis of Renal Acanthamoebiasis

“…In the immunocompromised mice, we found statistically significant differences in MCP-1 levels between the 16 dpi and control group, as well as between 24 dpi and control group. It is important to point out, that MCP-1 levels were statistically different compared to the control groups of mice at those days when the morphological changes in the kidneys were most visible in the histopathological examinations [ 4 ].…”

“…The histopathological examination of the kidneys of mice infected with Acanthamoeba spp. revealed a lighter color of the nucleus and cytoplasm of the renal tubules [ 4 ], which may indicate a process of fibrosis. This process is characterized by a lighter color on histological examination.…”

“…Based on the present study and the articles published so far, it is known that Acanthamoeba spp. activate TLR2 in the kidneys of mice [ 4 ]. Activation of TLR2 increases significantly and enhances the pro-inflammatory response of a tissue, with the participating of numerous cytokines and chemokines, including MCP-1 [ 68 , 69 ].…”

“…However, the presence of Acanthamoeba spp. in the kidneys is usually determined postmortem as serum and urine biochemistry are not always abnormal, and may vary depending on the immune status of the host and the amoebic strain [ 2 , 3 , 4 ]. Histological examinations of the kidneys of hosts infected with Acanthamoeba spp.…”

“…Histological examinations of the kidneys of hosts infected with Acanthamoeba spp. showed increased proliferation of cell nuclei in the proximal and distal tubular epithelium, mitotic figures, single lymphocytes [ 4 ], bloody ecchymoses, and inflammatory foci [ 5 ]. Extensive necrotic lesions of the renal tubules and glomeruli were also found in hosts infected with the environmental strain of Acanthamoeba [ 5 ].…”