A narrative of how the new gene editing technology might be the needed item in malaria eradication

1. ADAPTIVE BACTERIAL IMMUNITY,
GENE DRIVES AND THE
GENETIC CONTROL OF MALARIA
BY
ONILE-ERE OLABODE
14PCQ01211
DEPARTMENT OF BIOLOGICAL SCIENCES
MICROBIOLOGY UNIT
COVENANT UNIVERSITY, OTA
AUGUST, 2016.

2. Outline
• Background
• Malaria
• Adaptive Immunity In Bacteria
• CRISPR-CAS9 Genome engineering
• CRISPR-CAS9 in controlling malaria
• Gene Drive
• Population Replacement
• Population Suppression
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3. MALARIA IS A COMPLEX
DISEASE
• Drug Resistance
• Insecticide Resistance
• Misdiagnosis
• HRP-II Deletion
• Over and under Diagnosis
• Asymptomatic Reservoir (we don’t
fully understand this)
• Partial Immunity
• Hundreds of thousands die yearly
• Costs Africa 20billion USD yearly
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4. VISION 0:2030- Get to Zero by 2030
The WHO identified malaria control as being core to getting to zero
Current control strategies
• Insecticide Treated Nets
• Transmission Blocking
• Surveillance (T3)
• Indoor Residual Spraying
Issues
• Compliance
• Insecticide resistance
• Interventions are not ‘Africa-
proof’
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5. Way(s) Forward?
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6. Discovery of Adaptive Immunity In Bacteria
Figure 1- CRISPR Locus
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7. CRISPR Mechanism
Rath et al., 2015
Fig 2: CRISPR Adaptation Fig 3: Steps in CRISPR immunity 7

8. CRISPR-CAS9- Nature’s Find and Replace Tool
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9. CRISPR-CAS9 Genome Editing
NHEJ- Non-homologous End Joining (Knock-out)
HR- Homologous Directed Recombination (Knock-in)
Figure 4- CRISPR-CAS Genome Editing
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We Will come talk about this a bit more in the slides
to come

10. …and the CRISPR-CAS9 revolution was born
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11. But how does all of this information help us
control malaria?
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12. Genetic Control of Malaria
• Gene Drive- "stimulating biased inheritance of particular genes to
alter entire populations."
• Converting Heterozygous to Homozygous
• Block Parasite Development- Population Replacement
• Reduce Reproductive fitness- Population Suppression
Plasmodium Mosquito Human
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13. GENE DRIVE
• Mendelian inheritance will
eventually dilute out the
transgene
• To overcome this, one would
need to literally release more
transgenic males than there are
wild type females- UNREALISTIC
• Is there a way around this?
McLean& Jacobs-Lorena, (2016)Figure 5: Mendelian Inheritance VS
Gene Drive 13

14. CRISPR-CAS9 Gene Drive
Figure 6- CRISPR-CAS Genome Editing
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This is the outcome desired in a gene drive

15. Population Replacement- Gantz et al., 2015
Figure 7: Gene Drive 15
Mutagenic Chain Reaction
• Asian malaria vector Anopheles
stephensi
• Inserted antiplasmodial effector genes
m1C3 and m2A10 along with cas-gRNA
gene
• They reported that over about 95% of
the progeny carried inserted gene

16. Population Suppression- Hammond et al., 2016
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17. Suppression Versus Replacement
• Population Suppression
• Advantages
1. Can eliminate vector for more than one disease (e.g Aedes aegypti –Zika, Yellow Fever,
Dengue fever)
2. If successful can solve problem permanently
• Disadvantages
1. Could lead to extinction of an organism
2. Ecological safety
• Population Replacement
• Advantages
1. Can eliminate targeted disease without wiping out vector
2. Minimal ecological damage
• Disadvantages
1. Requires multiple implementations to eliminate all vector-mediated diseases (Intervention
is diseases specific i.e. can only handle one diseases per design)
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18. Pros, Cons and Issues
• Ethics
• Ecological costs/Unintended Outcomes
• Possibility of unintended outcomes
• Mosquitoes are required for pollination
• Fitness cost to mosquitoes hence eventual dilution of population
supressing gene
• Boost In GDP of tropical nations suffering from mosquito borne
diseases
• Boost in Tourism
• Brazil-Zika Conspiracy
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19. Conclusion
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Gene drives could potentially wipe out not just
malaria but every mosquito borne diseases
(Yellow Fever, Dengue, Zika etc). It is therefore
imperative that all hands are on deck to perfect
the technology in the achievement of a world
free of Malaria
National Academy of Sciences, 2016

20. References
• Jinek, M., Chylinski, K., Fonfara, I., Hauer, M., Doudna, J. A., & Charpentier, E. (2012). A programmable dual-RNA-guided DNA
endonuclease in adaptive bacterial immunity. Science (New York, N.Y.), 337(6096), 816–21.
http://doi.org/10.1126/science.1225829
• McLean, K. J., & Jacobs-Lorena, M. (2016). Genetic Control Of Malaria Mosquitoes. Trends in Parasitology, 32(3), 174–176.
http://doi.org/10.1016/j.pt.2016.01.002
• Rath, D., Amlinger, L., Rath, A., & Lundgren, M. (2015). The CRISPR-Cas immune system: Biology, mechanisms and applications.
Biochimie, 117, 119–128. http://doi.org/10.1016/j.biochi.2015.03.025
• Gantz, V. M., Jasinskiene, N., Tatarenkova, O., Fazekas, A., Macias, V. M., Bier, E., & James, A. A. (2015). Highly efficient Cas9-
mediated gene drive for population modification of the malaria vector mosquito Anopheles stephensi. Proceedings of the National
Academy of Sciences, 112(49), E6736–E6743. http://doi.org/10.1073/pnas.1521077112
• Hammond, A., Galizi, R., Kyrou, K., Simoni, A., Siniscalchi, C., Katsanos, D., … Nolan, T. (2016). A CRISPR-Cas9 gene drive system
targeting female reproduction in the malaria mosquito vector Anopheles gambiae. Nature Biotechnology, 34(1), 78–83.
http://doi.org/10.1038/nbt.3439
• Bolotin, A., Quinquis, B., Sorokin, A., & Dusko Ehrlich, S. (2005). Clustered regularly interspaced short palindrome repeats
(CRISPRs) have spacers of extrachromosomal origin. Microbiology, 151(8), 2551–2561. http://doi.org/10.1099/mic.0.28048-0
• Mojica, F. J. M., Díez-Villaseñor, C., García-Martínez, J., & Soria, E. (2005). Intervening sequences of regularly spaced prokaryotic
repeats derive from foreign genetic elements. Journal of Molecular Evolution, 60(2), 174–82. http://doi.org/10.1007/s00239-004-
0046-3
• Pourcel, C., Salvignol, G., & Vergnaud, G. (2005). CRISPR elements in Yersinia pestis acquire new repeats by preferential uptake of
bacteriophage DNA, and provide additional tools for evolutionary studies. Microbiology (Reading, England), 151(Pt 3), 653–63.
http://doi.org/10.1099/mic.0.27437-0
• National Academy of Sciences. (2016). Gene Drives on the Horizon Advancing Science, Navigating Uncertainty, and Aligning
Research with Public Values- Brief. Washington DC. Retrieved from http://nas-sites.org/gene-drives/ Assessed on 23/08/16.
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21. THANK YOU FOR YOUR TIME
IT BEGINS WITH YOU 21