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Published on: November 10, 2015
Association of EPCR Polymorphism rs867186-GG With Severity of Human Malaria
Juan Carlos Cespedes1, Jacqueline Hibbert1, Sri Krishna2
1Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States.
Background:
Cerebral malaria (CM) is characterized by the sequestration of Plasmodium-infected erythrocytes (pRBCs) to host brain microvasculature beds via P. falciparum erythrocyte membrane protein 1 (PfEMP1). Under normal conditions, activated protein C (APC) bound to endothelial protein C receptor (EPCR) has cytoprotective properties via the activation of protease-activated receptor 1 (PAR1). During malaria infection, pRBCs transports PfEMP1 to the membranes to bind EPCR in the same region as APC. As a result, APC is less capable of inducing cytoprotective effects via PAR1. Two studies involving adult malaria patients revealed that EPCR rs867186-GG allele is associated with protection against severe malaria, while three other studies involving child malaria patients could not show association between EPCR rs867186-GG genotype and severe malaria or increased mortality among children with CM.
Methods:
We examined the association between the EPCR rs867186-GG genotype and the protection against cerebral malaria. Peripheral blood samples were collected from 47 malaria patients and 34 healthy individuals from a study conducted from 2004 to 2007 at the NSCB Medical College Hospital in India. CM and malaria-associated complications were defined based on WHO criteria. Genomic DNA was isolated from the peripheral blood mononuclear cells. Primer sequences were designed to contain rs867186 of the PROCR gene (NM 006404) and were used to amplify a 660 bp product as described before. PCR products were purified, and DNA sequences were determined by Sanger Sequencing (Genewiz, NJ). Nonparametric tests were used to compare the groups. To analyze differences in allele frequencies, we used chi-squared or Fisher's exact tests for categorical variables if the expected values were less than 5. P-value <0.05 was considered statistically significant.
Results:
Our results showed significantly higher rates of AG and GG genotypes in CM patients compared to mild malaria (P = 0.0034).
Conclusion:
Our results indicate that rs867186-GG or rs867186-AG genotypes are not associated with protection against HCM.
Insights
The EPCR rs867186-GG genotype is not linked to protection against cerebral malaria (CM). Higher rates of AG and GG genotypes were observed in CM patients, suggesting no protective association.
Area of Science:
- Genetics
- Immunology
- Infectious Diseases
Background:
- Cerebral malaria (CM) involves Plasmodium-infected erythrocyte sequestration in brain microvasculature.
- Endothelial protein C receptor (EPCR) normally provides cytoprotection via protease-activated receptor 1 (PAR1).
- Malaria infection disrupts EPCR-mediated cytoprotection through PfEMP1 binding.
Purpose of the Study:
- To investigate the association between the EPCR rs867186-GG genotype and protection against cerebral malaria.
- To determine if specific EPCR genotypes influence susceptibility or resistance to severe malaria.
- To clarify conflicting findings regarding EPCR rs867186 and malaria severity in different populations.
Main Methods:
- Genomic DNA was isolated from peripheral blood of malaria patients and healthy individuals.
- The EPCR rs867186 polymorphism was genotyped using PCR and Sanger sequencing.
- Statistical analyses, including chi-squared or Fisher's exact tests, were used to compare genotype frequencies between groups.
Main Results:
- Significantly higher frequencies of the AG and GG genotypes were found in cerebral malaria patients compared to mild malaria patients (P = 0.0034).
- These findings contradict previous studies suggesting a protective role for the GG allele in adults.
- The study did not find an association between the rs867186-GG genotype and protection against HCM.
Conclusions:
- The EPCR rs867186-GG and rs867186-AG genotypes are not associated with protection against cerebral malaria.
- The observed higher prevalence of these genotypes in CM patients suggests they may be risk factors rather than protective factors.
- Further research is needed to elucidate the complex role of EPCR polymorphisms in malaria pathogenesis.
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