Astrocytes are the most abundant cells in the central nervous system that play roles in maintaining the blood-brain-barrier and in neural injury, including cerebral malaria, a severe complication of Plasmodium falciparum infection. Prostaglandin (PG) D2 is abundantly produced in the brain and regulates the sleep response. Moreover, PGD2 is a potential factor derived from P. falciparum within erythrocytes. Heme oxygenase-1 (HO-1) is catalyzing enzyme in heme breakdown process to release iron, carbon monoxide, and biliverdin/bilirubin, and may influence iron supply to the P. falciparum parasites. Here, we showed that treatment of a human astrocyte cell line, CCF-STTG1, with PGD2 significantly increased the expression levels of HO-1 mRNA by RT-PCR. Western blot analysis showed that PGD2 treatment increased the level of HO-1 protein, in a dose- and time-dependent manner. Thus, PGD2 may be involved in the pathogenesis of cerebral malaria by inducing HO-1 expression in malaria patients.
Animals ; Astrocytes/*enzymology ; Blotting, Western ; Cell Line ; Gene Expression Profiling ; Heme Oxygenase-1/*biosynthesis ; Humans ; Malaria, Cerebral/*pathology ; Malaria, Falciparum/*complications/*pathology ; Plasmodium falciparum/*pathogenicity ; Prostaglandins/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction

Child ; Cranial Nerve Injuries ; drug therapy ; etiology ; Diagnosis, Differential ; Female ; Glossopharyngeal Nerve ; pathology ; Humans ; Malaria, Cerebral ; complications ; diagnosis ; drug therapy ; Vagus Nerve ; pathology

The pathogenesis of cerebral malaria is biologically complex and involves multi-factorial mechanisms such as microvascular congestion, immunopathology by the pro-inflammatory cytokine and endothelial dysfunction. Recent data have suggested that a pleiotropic T-cell immunomodulatory protein (TIP) could effectively mediate inflammatory cytokines of mammalian immune response against acute graft-versus-host disease in animal models. In this study, we identified a conserved homologue of TIP in Plasmodium berghei (PbTIP) as a membrane protein in Plasmodium asexual stage. Compared with PBS control group, the pathology of experimental cerebral malaria (ECM) in rPbTIP intravenous injection (i.v.) group was alleviated by the downregulation of pro-inflammatory responses, and rPbTIP i.v. group elicited an expansion of regulatory T-cell response. Therefore, rPbTIP i.v. group displayed less severe brain pathology and feverish mice in rPbTIP i.v. group died from ECM. This study suggested that PbTIP may be a novel promising target to alleviate the severity of ECM.
Animals ; Brain ; Cytokines ; Down-Regulation ; Estrogens, Conjugated (USP) ; Graft vs Host Disease ; Injections, Intravenous ; Malaria, Cerebral ; Membrane Proteins ; Mice ; Models, Animal ; Pathology ; Plasmodium berghei ; Plasmodium ; Staphylococcal Protein A ; T-Lymphocytes