Malaria and Babesia

Golightly, Bilencia, Gyan

Despite its virulence, the pathophysiologic basis of P. falciparum disease and cerebral malaria is poorly understood. Sequestration of infected red blood cells (iRBCs) in the microvasculature is a major pathologic finding in P. falciparum infections. The repair of microvasculature damaged by infection may occur either by the proliferation or migration of local endothelial cells, or the recruitment of bone marrow-derived circulating endothelial progenitor cells (EPCs). We hypothesize that P. falciparum infection results in an imbalance between microvascular damage and repair. Cerebral malaria occurs when circulating EPCs are diminished and damaged endothelial cells cannot be replaced. To test this hypothesis, EPC levels and markers of bone marrow activation in P. falciparum-infected patients with different degrees of disease severity are being compared with normal uninfected controls. These studies are being performed in collaboration with the Noguchi Memorial Institute for Medical Research in Accra, Ghana.

In collaboration with investigators at the University of the Negev in Israel, a cell phone imaging system that can non-invasively detect malaria parasites in the blood is being developed. This project was funded as part of a Bill and Melinda Gates Foundation Grand Challenges Explorations to Create Low-Cost Cell Phone-Based Applications for Priority Global Health Conditions.

Women and ethnic minorities are underrepresented in biomedical science. Studies that define the factors that affect retention in the academic pipeline provide validated guidance to permit the full inclusion of all and diversification of the workforce.

Mirza AH, Das S, Pingle MR, Rundell MS, Armah G, Gyan B, Hodinka RL, Larone DH, Spitzer ED, Barany F, Golightly LM. A Multiplex PCR/LDR Assay for Viral Agents of Diarrhea with the Capacity to Genotype Rotavirus. Sci Rep. 2018 Sep 4;8(1):13215.

Remer I, Pierre-Destine LF, Tay D, Golightly LM, Bilenca A. In vivo noninvasive visualization of retinal perfusion dysfunction in murine cerebral malaria by camera-phone laser speckle imaging. J Biophotonics. 2019 Jan;12(1):e201800098.

Ahmed A, Daily JP, Lescano AG, Golightly LM, Fasina A. Challenges and Strategies for Biomedical Researchers Returning to Low- and Middle-Income Countries after Training. Am J Trop Med Hyg. 2020 Mar;102(3):494-496.

Lambert WM, Wells MT, Cipriano MF, Sneva JN, Morris JA, Golightly LM. Career choices of underrepresented and female postdocs in the biomedical sciences. Elife. 2020 Jan 3;9:e48774.

Kirkman

Malaria, a vector-borne disease, causes great morbidity and mortality in tropical and subtropical regions of the world. Crucial to the continuing burden of disease is the parasite’s ability to evade clearance in the host; both the ability to evade the host immune system by changing surface proteins inserted into the host red blood cell, a process termed antigenic variation, and the ability to develop drug resistance. Important to both of these parasite adaptations is the capacity of this eukaryotic pathogen, with a haploid genome for most of its lifecycle, to generate and incorporate DNA mutations. We aim to study malaria DNA recombination and repair in the context of disease pathogenesis, focusing on antigenic variation and the development of drug resistance.

To better understand the generation of genetic diversity within the multi-copy gene family, we are manipulating the parasite genome to determine how the parasite repairs damaged DNA. Similarly, we are studying the mechanisms by which a parasite becomes resistant to antimalarials by focusing on the ways in which the parasites acquire mutations in DNA. Using genetically modified parasites we are studying the ability of the parasite to generate point mutations and gene duplications that have been previously associated with drug resistance in the field. We are able to manipulate both copy number and specific sequences in order to further study the interplay of different pathways implicated in parasite drug resistance.

Heinberg A, Kirkman L. The molecular basis of antifolate resistance in Plasmodium falciparum: looking beyond point mutations. Ann N Y Acad Sci. 2015 Apr;1342(1):10-8.

Kirkman LA, Deitsch KW. Recombination and Diversification of the Variant Antigen Encoding Genes in the Malaria Parasite Plasmodium falciparum. Microbiol Spectr. 2014 Dec;2(6).

Kirkman LA, Lawrence EA, Deitsch KW. Malaria parasites utilize both homologous recombination and alternative end joining pathways to maintain genome integrity. Nucleic Acids Res. 2014 Jan;42(1):370-9.

Kümpornsin K, Modchang C, Heinberg A, Ekland EH, Jirawatcharadech P, Chobson P, Suwanakitti N, Chaotheing S, Wilairat P, Deitsch KW, Kamchonwongpaisan S, Fidock DA, Kirkman LA, Yuthavong Y, Chookajorn T. Origin of robustness in generating drug-resistant malaria parasites. Mol Biol Evol. 2014 Jul;31(7):1649-60.

Calhoun SF, Reed J, Alexander N, Mason CE, Deitsch KW, Kirkman LA. Chromosome End Repair and Genome Stability in Plasmodium falciparum. mBio. 2017 Aug 8;8(4):e00547-17.

Zhang X, Alexander N, Leonardi I, Mason C, Kirkman LA, Deitsch KW. Rapid antigen diversification through mitotic recombination in the human malaria parasite Plasmodium falciparum. PLoS Biol. 2019 May 13;17(5):e3000271.

Siao MC, Borner J, Perkins SL, Deitsch KW, Kirkman LA. Evolution of Host Specificity by Malaria Parasites through Altered Mechanisms Controlling Genome Maintenance. mBio. 2020 Mar 17;11(2):e03272-19.

Kirkman

There are confirmed P. falciparum parasites resistant to every available antimalarial, and thus also an urgent need to identify novel parasite targets for the next generation of therapeutics. My lab, in collaboration with the Tri-Institutional Therapeutics Discovery Institute and Dr. Gang Lin in Microbiology and Immunology, designed specific inhibitors of a novel drug target; the Plasmodium proteasome. In addition to developing potent and selective proteasome inhibitors that can kill the parasite in vitro an in vivo models, we identified unique aspects of proteasome inhibition in the parasite. We found synergistic parasite killing when two of the catalytically active proteasome, subunits termed β2 and β5, are targeted at the same time. Interestingly, there is also collateral sensitivity in β5 inhibitor resistant parasite lines, in that these parasites are hypersensitive to β2 inhibitors. Synergistic activity between inhibitors and collateral sensitivity serve as important mechanisms in the prevention of the emergence of resistant parasites. We are pursuing compounds with improved drug like qualities that target the parasite proteasome. In addition to providing potential compounds for use as therapeutics, this project is significant in its investigation of basic biology of the proteasome and the ubiquitin proteasome system in the malaria parasite.

Kirkman LA, Zhan W, Visone J, Dziedziech A, Singh PK, Fan H, Tong X, Bruzual I, Hara R, Kawasaki M, Imaeda T, Okamoto R, Sato K, Michino M, Alvaro EF, Guiang LF, Sanz L, Mota DJ, Govindasamy K, Wang R, Ling Y, Tumwebaze PK, Sukenick G, Shi L, Vendome J, Bhanot P, Rosenthal PJ, Aso K, Foley MA, Cooper RA, Kafsack B, Doggett JS, Nathan CF, Lin G. Antimalarial proteasome inhibitor reveals collateral sensitivity from intersubunit interactions and fitness cost of resistance. Proc Natl Acad Sci U S A. 2018 Jul 17;115(29):E6863-E6870.

Zhan W, Visone J, Ouellette T, Harris JC, Wang R, Zhang H, Singh PK, Ginn J, Sukenick G, Wong TT, Okoro JI, Scales RM, Tumwebaze PK, Rosenthal PJ, Kafsack BFC, Cooper RA, Meinke PT, Kirkman LA*, Lin G*. (co-corresponding author) Improvement of Asparagine Ethylenediamines as Anti-malarial Plasmodium-Selective Proteasome Inhibitors. J Med Chem. 2019 Jul 11;62(13):6137-6145.