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Ariff A, Song Y, Aguilar R, Nhabomba A, Manaca MN, Khoo SK, Wiertsema S, Bassat Q, Barbosa A, Quintó L, Laing IA, Guinovart C, Alonso PL, Dobaño C, Le Souëf P, Zhang G. Genetic variants of TLR4, including the novel variant, rs5030719, and related genes are associated with susceptibility to clinical malaria in African children. Malar J 2023; 22:177. [PMID: 37287037 DOI: 10.1186/s12936-023-04549-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 03/31/2023] [Indexed: 06/09/2023] Open
Abstract
BACKGROUND Malaria is a deadly disease caused by Plasmodium spp. Several blood phenotypes have been associated with malarial resistance, which suggests a genetic component to immune protection. METHODS One hundred and eighty-seven single nucleotide polymorphisms (SNPs) in 37 candidate genes were genotyped and investigated for associations with clinical malaria in a longitudinal cohort of 349 infants from Manhiça, Mozambique, in a randomized controlled clinical trial (RCT) (AgeMal, NCT00231452). Malaria candidate genes were selected according to involvement in known malarial haemoglobinopathies, immune, and pathogenesis pathways. RESULTS Statistically significant evidence was found for the association of TLR4 and related genes with the incidence of clinical malaria (p = 0.0005). These additional genes include ABO, CAT, CD14, CD36, CR1, G6PD, GCLM, HP, IFNG, IFNGR1, IL13, IL1A, IL1B, IL4R, IL4, IL6, IL13, MBL, MNSOD, and TLR2. Of specific interest, the previously identified TLR4 SNP rs4986790 and the novel finding of TRL4 SNP rs5030719 were associated with primary cases of clinical malaria. CONCLUSIONS These findings highlight a potential central role of TLR4 in clinical malarial pathogenesis. This supports the current literature and suggests that further research into the role of TLR4, as well as associated genes, in clinical malaria may provide insight into treatment and drug development.
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Affiliation(s)
- Amir Ariff
- Centre for Genetic Origins of Health and Disease, The University of Western Australia and Curtin University, Perth, WA, 6009, Australia
- School of Women's and Children's Health, University of New South Wales, Sydney, Australia
| | - Yong Song
- Centre for Genetic Origins of Health and Disease, The University of Western Australia and Curtin University, Perth, WA, 6009, Australia
- School of Public Health, Curtin University, Perth, WA, 6102, Australia
| | - Ruth Aguilar
- ISGlobal, Hospital Clínic of Barcelona, Universitat de Barcelona, 08036, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), 1929, Maputo, Mozambique
| | - Augusto Nhabomba
- Centro de Investigação em Saúde de Manhiça (CISM), 1929, Maputo, Mozambique
| | - Maria Nelia Manaca
- Centro de Investigação em Saúde de Manhiça (CISM), 1929, Maputo, Mozambique
| | - Siew-Kim Khoo
- Division of Cardiovascular and Respiratory Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- Telethon Kids Institute, The University of Western Australia, Perth, WA, 6008, Australia
| | - Selma Wiertsema
- Division of Cardiovascular and Respiratory Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- Telethon Kids Institute, The University of Western Australia, Perth, WA, 6008, Australia
| | - Quique Bassat
- ISGlobal, Hospital Clínic of Barcelona, Universitat de Barcelona, 08036, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), 1929, Maputo, Mozambique
- ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
- Pediatrics Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Esplugues, Barcelona, Spain
- Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Arnoldo Barbosa
- Centro de Investigação em Saúde de Manhiça (CISM), 1929, Maputo, Mozambique
| | - Llorenç Quintó
- ISGlobal, Hospital Clínic of Barcelona, Universitat de Barcelona, 08036, Barcelona, Spain
| | - Ingrid A Laing
- Division of Cardiovascular and Respiratory Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- Telethon Kids Institute, The University of Western Australia, Perth, WA, 6008, Australia
- School of Medicine, The University of Western Australia, Perth, WA, 6008, Australia
| | - Caterina Guinovart
- ISGlobal, Hospital Clínic of Barcelona, Universitat de Barcelona, 08036, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), 1929, Maputo, Mozambique
| | - Pedro L Alonso
- ISGlobal, Hospital Clínic of Barcelona, Universitat de Barcelona, 08036, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), 1929, Maputo, Mozambique
| | - Carlota Dobaño
- ISGlobal, Hospital Clínic of Barcelona, Universitat de Barcelona, 08036, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), 1929, Maputo, Mozambique
| | - Peter Le Souëf
- Division of Cardiovascular and Respiratory Sciences, The University of Western Australia, Perth, WA, 6009, Australia.
- Telethon Kids Institute, The University of Western Australia, Perth, WA, 6008, Australia.
- School of Medicine, The University of Western Australia, Perth, WA, 6008, Australia.
| | - Guicheng Zhang
- Centre for Genetic Origins of Health and Disease, The University of Western Australia and Curtin University, Perth, WA, 6009, Australia.
- School of Public Health, Curtin University, Perth, WA, 6102, Australia.
- Telethon Kids Institute, The University of Western Australia, Perth, WA, 6008, Australia.
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, 6102, Australia.
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Oyebola MK, Idowu ET, Olukosi YA, Iwalokun BA, Agomo CO, Ajibaye OO, Tola M, Otubanjo AO. Genetic diversity and complexity of Plasmodium falciparum infections in Lagos, Nigeria. Asian Pac J Trop Biomed 2014; 4:S87-91. [PMID: 25183154 DOI: 10.12980/apjtb.4.2014c1301] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 03/03/2014] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVE To analyse the genetic diversity of Plasmodium falciparum (P. falciparum) using msp-1 and msp-2 as antigenic markers. METHODS Parasite DNA was extracted from 100 blood samples collected from P. falciparum-positive patients confirmed by microscopy, and followed by PCR-genotyping targeting the msp-1 (block2) and msp-2 (block 3) allelic families. RESULTS All the families of msp-1 (K1, MAD20 and R033) and msp-2 (FC27 and 3D7) locus were observed. Results revealed that K1 (60/100) was the most predominant genotype of msp-1 allelic family followed by the genotypes of MAD20 (50/100) and R033 (45/100). In the msp-2 locus, FC27 genotype (62/100) showed higher frequency than 3D7 genotype (55/100). The allelic families were detected either alone or in combination with other families. However, no R033/MAD20 combination was observed. Multiplicity of infection (MOI) with msp-1 was higher in the locality of Ikorodu (1.50) than in Lekki (1.39). However, MOI with msp-2 was lower in the locality of Ikorodu (1.14) than in Lekki (1.76). There was no significant difference in the mean MOI between the two study areas (P=0.427). CONCLUSIONS The observation of limited diversity of malaria parasites may imply that the use of antigenic markers as genotyping tools for distinguishing recrudescence and re-infections with P. falciparum during drug trials is subjective.
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Affiliation(s)
- Muyiwa K Oyebola
- Parasitology and Bioinformatics, Faculty of Science University of Lagos, Nigeria ; Malaria Research Laboratory, Nigeria Institute of Medical Research, Lagos, Nigeria
| | - Emmanuel T Idowu
- Parasitology and Bioinformatics, Faculty of Science University of Lagos, Nigeria
| | - Yetunde A Olukosi
- Malaria Research Laboratory, Nigeria Institute of Medical Research, Lagos, Nigeria
| | - Bamidele A Iwalokun
- Malaria Research Laboratory, Nigeria Institute of Medical Research, Lagos, Nigeria
| | - Chimere O Agomo
- Malaria Research Laboratory, Nigeria Institute of Medical Research, Lagos, Nigeria
| | - Olusola O Ajibaye
- Malaria Research Laboratory, Nigeria Institute of Medical Research, Lagos, Nigeria
| | - Monday Tola
- Malaria Research Laboratory, Nigeria Institute of Medical Research, Lagos, Nigeria
| | - Adetoro O Otubanjo
- Parasitology and Bioinformatics, Faculty of Science University of Lagos, Nigeria
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Gomez F, Tomas G, Ko WY, Ranciaro A, Froment A, Ibrahim M, Lema G, Nyambo TB, Omar SA, Wambebe C, Hirbo JB, Rocha J, Tishkoff SA. Patterns of nucleotide and haplotype diversity at ICAM-1 across global human populations with varying levels of malaria exposure. Hum Genet 2013; 132:987-99. [PMID: 23609612 DOI: 10.1007/s00439-013-1284-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 02/27/2013] [Indexed: 10/26/2022]
Abstract
Malaria is one of the strongest selective pressures in recent human evolution. African populations have been and continue to be at risk for malarial infections. However, few studies have re-sequenced malaria susceptibility loci across geographically and genetically diverse groups in Africa. We examined nucleotide diversity at Intercellular adhesion molecule-1 (ICAM-1), a malaria susceptibility candidate locus, in a number of human populations with a specific focus on diverse African ethnic groups. We used tests of neutrality to assess whether natural selection has impacted this locus and tested whether SNP variation at ICAM-1 is correlated with malaria endemicity. We observe differing patterns of nucleotide and haplotype variation in global populations and higher levels of diversity in Africa. Although we do not observe a deviation from neutrality based on the allele frequency distribution, we do observe several alleles at ICAM-1, including the ICAM-1 (Kilifi) allele, that are correlated with malaria endemicity. We show that the ICAM-1 (Kilifi) allele, which is common in Africa and Asia, exists on distinct haplotype backgrounds and is likely to have arisen more recently in Asia. Our results suggest that correlation analyses of allele frequencies and malaria endemicity may be useful for identifying candidate functional variants that play a role in malaria resistance and susceptibility.
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Affiliation(s)
- Felicia Gomez
- Department of Genetics and Biology, School of Medicine and School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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4
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The host genetic diversity in malaria infection. J Trop Med 2012; 2012:940616. [PMID: 23316245 PMCID: PMC3532872 DOI: 10.1155/2012/940616] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 11/06/2012] [Accepted: 11/19/2012] [Indexed: 02/06/2023] Open
Abstract
Populations exposed to Plasmodium infection develop genetic mechanisms of protection against severe disease. The clinical manifestation of malaria results primarily from the lysis of infected erythrocytes and subsequent immune and inflammatory responses. Herein, we review the genetic alterations associated with erythrocytes or mediators of the immune system, which might influence malaria outcome. Moreover, polymorphisms in genes related to molecules involved in mechanisms of cytoadherence and their influence on malaria pathology are also discussed. The results of some studies have suggested that the combinatorial effects of a set of genetic factors in the erythrocyte-immunology pathway might be relevant to host resistance or susceptibility against Plasmodium infection. However, these results must be interpreted with caution because of the differences observed in the functionality and frequency of polymorphisms within different populations. With the recent advances in molecular biology techniques, more robust studies with reliable data have been reported, and the results of these studies have identified individual genetic factors for consideration in preventing severe disease and the individual response to treatment.
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Basu M, Das T, Ghosh A, Majumder S, Maji AK, Kanjilal SD, Mukhopadhyay I, Roychowdhury S, Banerjee S, Sengupta S. Gene-gene interaction and functional impact of polymorphisms on innate immune genes in controlling Plasmodium falciparum blood infection level. PLoS One 2012; 7:e46441. [PMID: 23071570 PMCID: PMC3470565 DOI: 10.1371/journal.pone.0046441] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 08/30/2012] [Indexed: 12/19/2022] Open
Abstract
Genetic variations in toll-like receptors and cytokine genes of the innate immune pathways have been implicated in controlling parasite growth and the pathogenesis of Plasmodium falciparum mediated malaria. We previously published genetic association of TLR4 non-synonymous and TNF-α promoter polymorphisms with P.falciparum blood infection level and here we extend the study considerably by (i) investigating genetic dependence of parasite-load on interleukin-12B polymorphisms, (ii) reconstructing gene-gene interactions among candidate TLRs and cytokine loci, (iii) exploring genetic and functional impact of epistatic models and (iv) providing mechanistic insights into functionality of disease-associated regulatory polymorphisms. Our data revealed that carriage of AA (P = 0.0001) and AC (P = 0.01) genotypes of IL12B 3′UTR polymorphism was associated with a significant increase of mean log-parasitemia relative to rare homozygous genotype CC. Presence of IL12B+1188 polymorphism in five of six multifactor models reinforced its strong genetic impact on malaria phenotype. Elevation of genetic risk in two-component models compared to the corresponding single locus and reduction of IL12B (2.2 fold) and lymphotoxin-α (1.7 fold) expressions in patients'peripheral-blood-mononuclear-cells under TLR4Thr399Ile risk genotype background substantiated the role of Multifactor Dimensionality Reduction derived models. Marked reduction of promoter activity of TNF-α risk haplotype (C-C-G-G) compared to wild-type haplotype (T-C-G-G) with (84%) and without (78%) LPS stimulation and the loss of binding of transcription factors detected in-silico supported a causal role of TNF-1031. Significantly lower expression of IL12B+1188 AA (5 fold) and AC (9 fold) genotypes compared to CC and under-representation (P = 0.0048) of allele A in transcripts of patients' PBMCs suggested an Allele-Expression-Imbalance. Allele (A+1188C) dependent differential stability (2 fold) of IL12B-transcripts upon actinomycin-D treatment and observed structural modulation (P = 0.013) of RNA-ensemble were the plausible explanations for AEI. In conclusion, our data provides functional support to the hypothesis that de-regulated receptor-cytokine axis of innate immune pathway influences blood infection level in P. falciparum malaria.
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Affiliation(s)
- Madhumita Basu
- Department of Biochemistry, University of Calcutta, Kolkata, West Bengal, India
| | - Tania Das
- Cancer & Cell Biology Division, Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Alip Ghosh
- Centre for Liver Research, The Institute of Post-Graduate Medical Education & Research, Kolkata, West Bengal, India
| | - Subhadipa Majumder
- Department of Biochemistry, University of Calcutta, Kolkata, West Bengal, India
| | - Ardhendu Kumar Maji
- Department of Protozoology, The Calcutta School of Tropical Medicine, Kolkata, West Bengal, India
| | - Sumana Datta Kanjilal
- Department of Pediatric Medicine, Calcutta National Medical College, Kolkata, West Bengal, India
| | | | - Susanta Roychowdhury
- Cancer & Cell Biology Division, Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Soma Banerjee
- Centre for Liver Research, The Institute of Post-Graduate Medical Education & Research, Kolkata, West Bengal, India
| | - Sanghamitra Sengupta
- Department of Biochemistry, University of Calcutta, Kolkata, West Bengal, India
- * E-mail:
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Variation in human genes encoding adhesion and proinflammatory molecules are associated with severe malaria in the Vietnamese. Genes Immun 2012; 13:503-8. [PMID: 22673309 DOI: 10.1038/gene.2012.25] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The genetic basis for susceptibility to malaria has been studied widely in African populations but less is known of the contribution of specific genetic variants in Asian populations. We genotyped 67 single-nucleotide polymorphisms (SNPs) in 1030 severe malaria cases and 2840 controls from Vietnam. After data quality control, genotyping data of 956 cases and 2350 controls were analysed for 65 SNPs (3 gender confirmation, 62 positioned in/near 42 malarial candidate genes). A total of 14 SNPs were monomorphic and 2 (rs8078340 and rs33950507) were not in Hardy-Weinberg equilibrium in controls (P<0.01). In all, 7/46 SNPs in 6 genes (ICAM1, IL1A, IL17RC, IL13, LTA and TNF) were associated with severe malaria, with 3/7 SNPs in the TNF/LTA region. Genotype-phenotype correlations between SNPs and clinical parameters revealed that genotypes of rs708567 (IL17RC) correlate with parasitemia (P=0.028, r(2)=0.0086), with GG homozygotes having the lowest parasite burden. Additionally, rs708567 GG homozygotes had a decreased risk of severe malaria (P=0.007, OR=0.78 (95% CI; 0.65-0.93)) and death (P=0.028, OR=0.58 (95% CI; 0.37-0.93)) than those with AA and AG genotypes. In summary, variants in six genes encoding adhesion and proinflammatory molecules are associated with severe malaria in the Vietnamese. Further replicative studies in independent populations will be necessary to confirm these findings.
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Driss A, Hibbert JM, Wilson NO, Iqbal SA, Adamkiewicz TV, Stiles JK. Genetic polymorphisms linked to susceptibility to malaria. Malar J 2011; 10:271. [PMID: 21929748 PMCID: PMC3184115 DOI: 10.1186/1475-2875-10-271] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 09/19/2011] [Indexed: 12/26/2022] Open
Abstract
The influence of host genetics on susceptibility to Plasmodium falciparum malaria has been extensively studied over the past twenty years. It is now clear that malaria parasites have imposed strong selective forces on the human genome in endemic regions. Different genes have been identified that are associated with different malaria related phenotypes. Factors that promote severity of malaria include parasitaemia, parasite induced inflammation, anaemia and sequestration of parasitized erythrocytes in brain microvasculature. Recent advances in human genome research technologies such as genome-wide association studies (GWAS) and fine genotyping tools have enabled the discovery of several genetic polymorphisms and biomarkers that warrant further study in host-parasite interactions. This review describes and discusses human gene polymorphisms identified thus far that have been shown to be associated with susceptibility or resistance to P. falciparum malaria. Although some polymorphisms play significant roles in susceptibility to malaria, several findings are inconclusive and contradictory and must be considered with caution. The discovery of genetic markers associated with different malaria phenotypes will help elucidate the pathophysiology of malaria and enable development of interventions or cures. Diversity in human populations as well as environmental effects can influence the clinical heterogeneity of malaria, thus warranting further investigations with a goal of developing new interventions, therapies and better management against malaria.
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Affiliation(s)
- Adel Driss
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, Georgia, USA.
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8
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Sambo MR, Trovoada MJ, Benchimol C, Quinhentos V, Gonçalves L, Velosa R, Marques MI, Sepúlveda N, Clark TG, Mustafa S, Wagner O, Coutinho A, Penha-Gonçalves C. Transforming growth factor beta 2 and heme oxygenase 1 genes are risk factors for the cerebral malaria syndrome in Angolan children. PLoS One 2010; 5:e11141. [PMID: 20585394 PMCID: PMC2886838 DOI: 10.1371/journal.pone.0011141] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 05/21/2010] [Indexed: 11/30/2022] Open
Abstract
Background Cerebral malaria (CM) represents a severe outcome of the Plasmodium falciparum infection. Recent genetic studies have correlated human genes with severe malaria susceptibility, but there is little data on genetic variants that increase the risk of developing specific malaria clinical complications. Nevertheless, susceptibility to experimental CM in the mouse has been linked to host genes including Transforming Growth Factor Beta 2 (TGFB2) and Heme oxygenase-1 (HMOX1). Here, we tested whether those genes were governing the risk of progressing to CM in patients with severe malaria syndromes. Methodology/Principal Findings We report that the clinical outcome of P. falciparum infection in a cohort of Angolan children (n = 430) correlated with nine TGFB2 SNPs that modify the risk of progression to CM as compared to other severe forms of malaria. This genetic effect was explained by two haplotypes harboring the CM-associated SNPs (Pcorrec. = 0.035 and 0.036). In addition, one HMOX1 haplotype composed of five CM-associated SNPs increased the risk of developing the CM syndrome (Pcorrec. = 0.002) and was under-transmitted to children with uncomplicated malaria (P = 0.036). Notably, the HMOX1-associated haplotype conferred increased HMOX1 mRNA expression in peripheral blood cells of CM patients (P = 0.012). Conclusions/Significance These results represent the first report on CM genetic risk factors in Angolan children and suggest the novel hypothesis that genetic variants of the TGFB2 and HMOX1 genes may contribute to confer a specific risk of developing the CM syndrome in patients with severe P. falciparum malaria. This work may provide motivation for future studies aiming to replicate our findings in larger populations and to confirm a role for these genes in determining the clinical course of malaria.
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Affiliation(s)
- Maria Rosário Sambo
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Hospital Pediátrico David Bernardino, Luanda, Angola
- Faculdade de Medicina, Universidade Agostinho Neto, Luanda, Angola
| | | | | | | | | | - Rute Velosa
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | | | - Taane G. Clark
- Departments of Epidemiology and Public Health and Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Stefan Mustafa
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Oswald Wagner
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
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Adhesion of Plasmodium falciparum-infected erythrocytes to human cells: molecular mechanisms and therapeutic implications. Expert Rev Mol Med 2009; 11:e16. [PMID: 19467172 PMCID: PMC2878476 DOI: 10.1017/s1462399409001082] [Citation(s) in RCA: 268] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Severe malaria has a high mortality rate (15–20%) despite treatment with
effective antimalarial drugs. Adjunctive therapies for severe malaria that target the
underlying disease process are therefore urgently required. Adhesion of erythrocytes
infected with Plasmodium falciparum to human cells has a key role in the
pathogenesis of life-threatening malaria and could be targeted with antiadhesion therapy.
Parasite adhesion interactions include binding to endothelial cells (cytoadherence),
rosetting with uninfected erythrocytes and platelet-mediated clumping of infected
erythrocytes. Recent research has started to define the molecular mechanisms of parasite
adhesion, and antiadhesion therapies are being explored. However, many fundamental
questions regarding the role of parasite adhesion in severe malaria remain unanswered.
There is strong evidence that rosetting contributes to severe malaria in sub-Saharan
Africa; however, the identity of other parasite adhesion phenotypes that are implicated in
disease pathogenesis remains unclear. In addition, the possibility of geographic variation
in adhesion phenotypes causing severe malaria, linked to differences in malaria
transmission levels and host immunity, has been neglected. Further research is needed to
realise the untapped potential of antiadhesion adjunctive therapies, which could
revolutionise the treatment of severe malaria and reduce the high mortality rate of the
disease.
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10
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Fry AE, Auburn S, Diakite M, Green A, Richardson A, Wilson J, Jallow M, Sisay-Joof F, Pinder M, Griffiths MJ, Peshu N, Williams TN, Marsh K, Molyneux ME, Taylor TE, Rockett KA, Kwiatkowski DP. Variation in the ICAM1 gene is not associated with severe malaria phenotypes. Genes Immun 2008; 9:462-9. [PMID: 18528404 DOI: 10.1038/gene.2008.38] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Evidence from autopsy and in vitro binding studies suggests that adhesion of erythrocytes infected with Plasmodium falciparum to the human host intercellular adhesion molecule (ICAM)-1 receptor is important in the pathogenesis of severe malaria. Previous association studies between polymorphisms in the ICAM1 gene and susceptibility to severe malarial phenotypes have been inconclusive and often contradictory. We performed genetic association studies with 15 single nucleotide polymorphisms (SNPs) around the ICAM1 locus. All SNPs were screened in a family study of 1071 trios from The Gambia, Malawi and Kenya. Two key non-synonymous SNPs with previously reported associations, rs5491 (K56M or 'ICAM-1(Kilifi)') and rs5498 (K469E), were tested in an additional 708 Gambian trios and a case-control study of 4058 individuals. None of the polymorphisms were associated with severe malaria phenotypes. Pooled results across our studies for ICAM-1(Kilifi) were, in severe malaria, odds ratio (OR) 1.02, 95% confidence interval (CI) 0.96-1.09, P=0.54, and cerebral malaria OR 1.07, CI 0.97-1.17, P=0.17. We assess the available epidemiological, population genetic and functional evidence that links ICAM-1(Kilifi) to severe malaria susceptibility.
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Affiliation(s)
- A E Fry
- The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, UK.
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Sirugo G, Hennig BJ, Adeyemo AA, Matimba A, Newport MJ, Ibrahim ME, Ryckman KK, Tacconelli A, Mariani-Costantini R, Novelli G, Soodyall H, Rotimi CN, Ramesar RS, Tishkoff SA, Williams SM. Genetic studies of African populations: an overview on disease susceptibility and response to vaccines and therapeutics. Hum Genet 2008; 123:557-98. [PMID: 18512079 DOI: 10.1007/s00439-008-0511-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 05/07/2008] [Indexed: 01/13/2023]
Abstract
Africa is the ultimate source of modern humans and as such harbors more genetic variation than any other continent. For this reason, studies of the patterns of genetic variation in African populations are crucial to understanding how genes affect phenotypic variation, including disease predisposition. In addition, the patterns of extant genetic variation in Africa are important for understanding how genetic variation affects infectious diseases that are a major problem in Africa, such as malaria, tuberculosis, schistosomiasis, and HIV/AIDS. Therefore, elucidating the role that genetic susceptibility to infectious diseases plays is critical to improving the health of people in Africa. It is also of note that recent and ongoing social and cultural changes in sub-Saharan Africa have increased the prevalence of non-communicable diseases that will also require genetic analyses to improve disease prevention and treatment. In this review we give special attention to many of the past and ongoing studies, emphasizing those in Sub-Saharan Africans that address the role of genetic variation in human disease.
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Affiliation(s)
- Giorgio Sirugo
- Medical Research Council Laboratories, Fajara, The Gambia, West Africa.
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Sakuntabhai A, Ndiaye R, Casadémont I, Peerapittayamongkol C, Rogier C, Tortevoye P, Tall A, Paul R, Turbpaiboon C, Phimpraphi W, Trape JF, Spiegel A, Heath S, Mercereau-Puijalon O, Dieye A, Julier C. Genetic determination and linkage mapping of Plasmodium falciparum malaria related traits in Senegal. PLoS One 2008; 3:e2000. [PMID: 18431485 PMCID: PMC2295258 DOI: 10.1371/journal.pone.0002000] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Accepted: 03/10/2008] [Indexed: 11/19/2022] Open
Abstract
Plasmodium falciparum malaria episodes may vary considerably in their severity and clinical manifestations. There is good evidence that host genetic factors contribute to this variability. To date, most genetic studies aiming at the identification of these genes have used a case/control study design for severe malaria, exploring specific candidate genes. Here, we performed a family-based genetic study of falciparum malaria related phenotypes in two independent longitudinal survey cohorts, as a first step towards the identification of genes and mechanisms involved in the outcome of infection. We studied two Senegalese villages, Dielmo and Ndiop that differ in ethnicity, malaria transmission and endemicity. We performed genome-scan linkage analysis of several malaria-related phenotypes both during clinical attacks and asymptomatic infection. We show evidence for a strong genetic contribution to both the number of clinical falciparum malaria attacks and the asymptomatic parasite density. The asymptomatic parasite density showed linkage to chromosome 5q31 (LOD = 2.26, empirical p = 0.0014, Dielmo), confirming previous findings in other studies. Suggestive linkage values were also obtained at three additional chromosome regions: the number of clinical malaria attacks on chromosome 5p15 (LOD = 2.57, empirical p = 0.001, Dielmo) and 13q13 (LOD = 2.37, empirical p = 0.0014 Dielmo), and the maximum parasite density during asymptomatic infection on chromosome 12q21 (LOD = 3.1, empirical p<10−4, Ndiop). While regions of linkage show little overlap with genes known to be involved in severe malaria, the four regions appear to overlap with regions linked to asthma or atopy related traits, suggesting that common immune related pathways may be involved.
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Affiliation(s)
- Anavaj Sakuntabhai
- Institut Pasteur, Unité de Génétique des Maladies Infectieuses et Autoimmunes, Paris, France.
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The Institut Pasteur: 120years of research in microbiology. Res Microbiol 2007; 159:5-14. [PMID: 18191546 DOI: 10.1016/j.resmic.2007.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Accepted: 11/07/2007] [Indexed: 11/21/2022]
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