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Ingham V, Nagi S. Genomic Profiling of Insecticide Resistance in Malaria Vectors: Insights into Molecular Mechanisms. RESEARCH SQUARE 2024:rs.3.rs-3910702. [PMID: 38410472 PMCID: PMC10896400 DOI: 10.21203/rs.3.rs-3910702/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Malaria control faces challenges from widespread insecticide resistance in major Anopheles species. This study, employing a cross-species approach, integrates RNA-Sequencing, whole-genome sequencing, and microarray data to elucidate drivers of insecticide resistance in Anopheles gambiae complex and An. funestus. Findings show an inverse relationship between genetic diversity and gene expression, with highly expressed genes experiencing stronger purifying selection. These genes cluster physically in the genome, revealing potential coordinated regulation. We identified known and novel candidate insecticide resistance genes, enriched in metabolic, cuticular, and behavioural functions. We also present AnoExpress, a Python package, and an online interface for user-friendly exploration of resistance candidate expression. Despite millions of years of speciation, convergent gene expression responses to insecticidal selection pressures are observed across Anopheles species, providing crucial insights for malaria vector control. This study culminates in a rich dataset that allows us to understand molecular mechanisms, better enabling us to combat insecticide resistance effectively.
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Fadel AN, Ibrahim SS, Sandeu MM, Tatsinkou CGM, Menze BD, Irving H, Hearn J, Nagi SC, Weedall GD, Terence E, Tchapga W, Wanji S, Wondji CS. Exploring the molecular mechanisms of increased intensity of pyrethroid resistance in Central African population of a major malaria vector Anopheles coluzzii. Evol Appl 2024; 17:e13641. [PMID: 38410533 PMCID: PMC10895554 DOI: 10.1111/eva.13641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/14/2023] [Accepted: 01/01/2024] [Indexed: 02/28/2024] Open
Abstract
Molecular mechanisms driving the escalation of pyrethroid resistance in the major malaria mosquitoes of Central Africa remain largely uncharacterized, hindering effective management strategies. Here, resistance intensity and the molecular mechanisms driving it were investigated in a population of Anopheles coluzzii from northern Cameroon. High levels of pyrethroid and organochloride resistance were observed in An. coluzzii population, with no mortality for 1× permethrin; only 11% and 33% mortalities for 5× and 10× permethrin diagnostic concentrations, and <2% mortalities for deltamethrin and DDT, respectively. Moderate bendiocarb resistance (88% mortality) and full susceptibility to malathion were observed. Synergist bioassays with piperonyl butoxide recovered permethrin susceptibility, with mortalities increasing to 53.39%, and 87.30% for 5× and 10× permethrin, respectively, implicating P450 monooxygenases. Synergist bioassays with diethyl maleate (DEM) recovered permethrin and DDT susceptibilities (mortalities increasing to 34.75% and 14.88%, respectively), implicating glutathione S-transferases. RNA-seq-based genome-wide transcriptional analyses supported by quantitative PCR identified glutathione S-transferase, GSTe2 (RNA-seqFC = 2.93 and qRT-PCRFC = 8.4, p < 0.0043) and CYP450, CYP6Z2 (RNA-seqFC = 2.39 and qRT-PCRFC = 11.7, p < 0.0177) as the most overexpressed detoxification genes in the pyrethroid-resistant mosquitoes, compared to mosquitoes of the susceptible Ngousso colony. Other overexpressed genes include P450s, CYP6M2 (FC = 1.68, p < 0.0114), CYP4G16 (FC = 2.02, p < 0.0005), and CYP4G17 (FC = 1.86, p < 0.0276). While high frequency of the 1014F kdr mutation (50%) and low frequencies of 1014S (6.61%) and 1575Y (10.29%) were observed, no ace-1 mutation was detected in bendiocarb-resistant populations, suggesting the preeminent role of metabolic mechanism. Overexpression of metabolic resistance genes (including GSTe2 and CYP6Z2 known to confer resistance to multiple insecticides) in An. coluzzii from the Sudan Savannah of Cameroon highlights the need for alternative management strategies to reduce malaria burden in northern Cameroon.
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Affiliation(s)
- Amen N. Fadel
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Sulaiman S. Ibrahim
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of BiochemistryBayero UniversityKanoNigeria
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Maurice M. Sandeu
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Microbiology and Infectious DiseasesSchool of Veterinary Medicine and SciencesUniversity of NgaoundéréNgaoundéréCameroon
| | | | | | - Helen Irving
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Jack Hearn
- Centre of Epidemiology and Planetary HealthNorth FacultyVeterinary & Animal ScienceScotland's Rural CollegeInvernessUK
| | - Sanjay C. Nagi
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Gareth D. Weedall
- School of Biological and Environmental SciencesLiverpool John Moores UniversityLiverpoolUK
| | - Ebai Terence
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
| | - Williams Tchapga
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
| | - Samuel Wanji
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Charles S. Wondji
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
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Dyer NA, Lucas ER, Nagi SC, McDermott DP, Brenas JH, Miles A, Clarkson CS, Mawejje HD, Wilding CS, Halfon MS, Asma H, Heinz E, Donnelly MJ. Mechanisms of transcriptional regulation in Anopheles gambiae revealed by allele specific expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.22.568226. [PMID: 38045426 PMCID: PMC10690255 DOI: 10.1101/2023.11.22.568226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Malaria control relies on insecticides targeting the mosquito vector, but this is increasingly compromised by insecticide resistance, which can be achieved by elevated expression of detoxifying enzymes that metabolize the insecticide. In diploid organisms, gene expression is regulated both in cis, by regulatory sequences on the same chromosome, and by trans acting factors, affecting both alleles equally. Differing levels of transcription can be caused by mutations in cis-regulatory modules (CRM), but few of these have been identified in mosquitoes. We crossed bendiocarb resistant and susceptible Anopheles gambiae strains to identify cis-regulated genes that might be responsible for the resistant phenotype using RNAseq, and cis-regulatory module sequences controlling gene expression in insecticide resistance relevant tissues were predicted using machine learning. We found 115 genes showing allele specific expression in hybrids of insecticide susceptible and resistant strains, suggesting cis regulation is an important mechanism of gene expression regulation in Anopheles gambiae. The genes showing allele specific expression included a higher proportion of Anopheles specific genes on average younger than genes those with balanced allelic expression.
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Affiliation(s)
- Naomi A Dyer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Eric R Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Sanjay C Nagi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Daniel P McDermott
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jon H Brenas
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Alistair Miles
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Chris S Clarkson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Henry D Mawejje
- Infectious Diseases Research Collaboration (IDRC), Plot 2C Nakasero Hill Road, P.O.Box 7475, Kampala, Uganda
| | - Craig S Wilding
- School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Marc S Halfon
- Department of Biochemistry, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo-State University of New York, 955 Main Street, Buffalo, New York 14203, USA
| | - Hasiba Asma
- Department of Biochemistry, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo-State University of New York, 955 Main Street, Buffalo, New York 14203, USA
| | - Eva Heinz
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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Ibrahim SS, Muhammad A, Hearn J, Weedall GD, Nagi SC, Mukhtar MM, Fadel AN, Mugenzi LJ, Patterson EI, Irving H, Wondji CS. Molecular drivers of insecticide resistance in the Sahelo-Sudanian populations of a major malaria vector Anopheles coluzzii. BMC Biol 2023; 21:125. [PMID: 37226196 DOI: 10.1186/s12915-023-01610-5] [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: 04/01/2022] [Accepted: 05/03/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Information on common markers of metabolic resistance in malaria vectors from countries sharing similar eco-climatic characteristics can facilitate coordination of malaria control. Here, we characterized populations of the major malaria vector Anopheles coluzzii from Sahel region, spanning four sub-Saharan African countries: Nigeria, Niger, Chad and Cameroon. RESULTS Genome-wide transcriptional analysis identified major genes previously implicated in pyrethroid and/or cross-resistance to other insecticides, overexpressed across the Sahel, including CYP450s, glutathione S-transferases, carboxylesterases and cuticular proteins. Several, well-known markers of insecticide resistance were found in high frequencies-including in the voltage-gated sodium channel (V402L, I940T, L995F, I1527T and N1570Y), the acetylcholinesterase-1 gene (G280S) and the CYP4J5-L43F (which is fixed). High frequencies of the epidemiologically important chromosomal inversion polymorphisms, 2La, 2Rb and 2Rc, were observed (~80% for 2Rb and 2Rc). The 2La alternative arrangement is fixed across the Sahel. Low frequencies of these inversions (<10%) were observed in the fully insecticide susceptible laboratory colony of An. coluzzii (Ngoussou). Several of the most commonly overexpressed metabolic resistance genes sit in these three inversions. Two commonly overexpressed genes, GSTe2 and CYP6Z2, were functionally validated. Transgenic Drosophila melanogaster flies expressing GSTe2 exhibited extremely high DDT and permethrin resistance (mortalities <10% in 24h). Serial deletion of the 5' intergenic region, to identify putative nucleotide(s) associated with GSTe2 overexpression, revealed that simultaneous insertion of adenine nucleotide and a transition (T->C), between Forkhead box L1 and c-EST putative binding sites, were responsible for the high overexpression of GSTe2 in the resistant mosquitoes. Transgenic flies expressing CYP6Z2 exhibited marginal resistance towards 3-phenoxybenzylalcohol (a primary product of pyrethroid hydrolysis by carboxylesterases) and a type II pyrethroid, α-cypermethrin. However, significantly higher mortalities were observed in CYP6Z2 transgenic flies compared with controls, on exposure to the neonicotinoid, clothianidin. This suggests a possible bioactivation of clothianidin into a toxic intermediate, which may make it an ideal insecticide against populations of An. coluzzii overexpressing this P450. CONCLUSIONS These findings will facilitate regional collaborations within the Sahel region and refine implementation strategies through re-focusing interventions, improving evidence-based, cross-border policies towards local and regional malaria pre-elimination.
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Affiliation(s)
- Sulaiman S Ibrahim
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK.
- Department of Biochemistry, Bayero University, PMB 3011, Kano, Nigeria.
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Abdullahi Muhammad
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK
- Centre for Biotechnology Research, Bayero University, PMB 3011, Kano, Nigeria
| | - Jack Hearn
- Centre of Epidemiology and Planetary Health, Veterinary & Animal Science, Scotland's Rural College, Inverness, IV2 5NA, UK
| | - Gareth D Weedall
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Sanjay C Nagi
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK
| | | | - Amen N Fadel
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Leon J Mugenzi
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Edward I Patterson
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
| | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK
| | - Charles S Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
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