Key points are not available for this paper at this time.
On 18–22 February this year, the seventh Molecular Approaches to Malaria Conference (MAM) was held in Lorne, Australia. A total of 431 delegates were welcomed to the conference by co-chairs Matthew Dixon University of Melbourne and Walter and Eliza Hall Institute of Medical Research (WEHI), Denise Doolan (University of Queensland), Michelle Boyle (Burnet Institute), and Chris Tonkin (WEHI), and to the country by the Eastern Maar Aboriginal Corporation. Jean-Luc Bodmer (Bill and Melinda Gates Foundation) commenced the scientific talks with his keynote on new tools and strategies for malaria elimination and was followed by a heartfelt tribute to the late Dominic Kwiatowski by Julian Rayner (University of Cambridge). A breadth of malaria research was covered in two flash talk sessions (21 speakers), two poster sessions (251 presenters), and three workshops ('Career Paths in Science', 'Drug Discovery', and 'Molecular Surveillance'). Delegates engaged not only with the cutting-edge science but with all that the conference and Lorne had to offer, including morning runs and a Gala Dinner complete with a late-night dance floor. In this TrendsTalk, we invite early-career researchers to highlight the exciting science presented across nine themed sessions. We hope this entices you to attend the eighth MAM in 2028! Rhea J. Longley Josephine Malinga Eva Hesping Photini Sinnis (Johns Hopkins University) opened the Life Cycle Biology session by challenging the notion that all infected mosquitoes are infectious. She revealed a 7.5 times higher infection rate when mosquitoes carry over 10 000 salivary-derived sporozoites. Photini found a strong correlation between sporozoite injection and salivary gland sporozoite loads, supporting the notion that highly infected mosquitoes are more likely to cause blood-stage infections. Friedrich Frischknecht (Heidelberg University) discussed Plasmodium development in mosquitoes, emphasizing a microtubule-based push–pull mechanism crucial for gamete formation. He and his team also identified an essential Arp2/3 complex for genome separation during male gamete formation and transmission. Furthermore, he proposed a novel vaccine strategy involving screening for slow-growth or low-virulence mutants, with five out of 17 mutants providing protection against disease when challenged with wild-type sporozoites. Hardik Patel (Seattle Children's Research Institute) showed that interferon-gamma (IFNγ) suppresses Plasmodium liver-stage infections by triggering noncanonical autophagy via GABA receptor-associated protein (GABARAP)-mediated lysosomal fusion and NOX2 protein-mediated ROS production, challenging the necessity of nitric oxide production as previously believed. Liliana Mancio-Silva (Institut Pasteur) utilized a bioengineered human micro-liver platform to capture single-cell transcriptomics of patient-derived Plasmodium vivax parasites, including the elusive dormant hypnozoite stages, and identified a ten-gene hypnozoite-specific transcriptional signature. Liliana also found that hypnozoites inhabit different host cells from replicative parasites, suggesting a role of the host cell environment in hypnozoite development. Lauren Carruthers (University of Glasgow) discovered Apicomplexa-specific zinc-finger proteins (ZINGER) with RNA-binding abilities and varying expression across the life cycle. ZINGER 3, for instance, binds RNA related to protein transport and regulates translation rather than transcription of its RNA targets. Abhinay Ramaprasad (Francis Crick Institute) closed the session by introducing SHIFTiKO, a novel method for pooled inducible knockout screens, using barcoded repair templates to insert loxP sites within target genes such that induced DiCre-mediated excisions result in frameshift mutations that ablate gene function. Edwin Sutanto Isabella Oyier (KEMRI Wellcome Trust) reported on the success of the integrating malaria molecular epidemiology into routine surveillance (IMMERSE) program in Kenya. The program found that lumefantrine introduction drives selection of the multidrug resistance genotype and that <2% of cases in the Coastal region of Kenya contained the double hrp gene deletion. Alexander Waiganjo Macharia (KEMRI Wellcome Trust) analyzed the impact of β-thalassemia on red blood cell (RBC) invasion. Alexander found 25% invasion efficiency reduction in β-thalassemia heterozygotes compared with normal, but the effect was reduced when β-thalassemia is co-inherited with α-thalassemia. Amy Ibrahim (London School of Hygiene and Tropical Medicine) curated and analyzed the largest global genomic dataset of Plasmodium malariae using selective whole-genome amplification. Distinct clusters were seen between Asian and African isolates, and many mutations were found within genes associated with anti-malarial drug susceptibility. Amy investigated the phenotype of variants found within dihydrofolate reductase (DHFR) using ortholog replacement in Plasmodium knowlesi and found reduced susceptibility to pyrimethamine. Sarah Auburn (Menzies School of Health Research) highlighted the use of genome-wide identity-by-descent (IBD) to tease apart the cause of P. vivax recurrence. With vivaxGEN, Sarah also developed 93 P. vivax microhaplotype markers, which can capture similar information to genome-wide IBD and inform on transmission dynamics. Yannick Höppner (Bernhard-Nocht Institute for Tropical Medicine) found different var gene expression profiles between naïve and pre-exposed Plasmodium falciparum patients, caused by existing PfEMP1 antibodies. After the initial infection, B-type var genes are highly expressed and switch frequently whilst C-type var genes maintain infection during the end stage but at the cost of weaker cytoadhesion. Nguyen Thanh Thuy Nhien (Oxford University Clinical Research Unit) reported the success of genetic surveillance to support the National Malaria Control Program (NMCP) in Vietnam. The data has informed the NMCP of possible drug resistance emergence, prompting change to anti-malarial combinations and alterations in the circulating parasite population following transition in treatment guidelines. Sophia M. DonVito The session was kicked off by Yi-Wei Chang (University of Pennsylvania) showcasing cryogenic microscopy techniques to investigate rhoptry secretion in apicomplexans, leading to discovery of the rhoptry secretory apparatus (RSA). The group used cryo-electron tomography to clearly render rhoptries in 3D, and a new cryo-confocal fluorescence light microscope (fLM) and cryogenic focused ion beam-scanning electron microscope (cryo-FIB-SEM) workflow to produce detailed images of P. falciparum interfacing RBCs. Rhoptry biology was a recurring theme, with Vasant Muralidharan (University of Georgia) showing that RON11 is essential for P. falciparum rhoptry biogenesis, and that without it, merozoites develop with only a single rhoptry and lose their ability to invade. This begs the question, do the two Plasmodium rhoptries contain different proteins? Emma Jones (University of Cambridge) then presented videos demonstrating the use of optical tweezers to 'catch' a merozoite between two RBCs, then carefully pull them apart to measure host–parasite interaction forces. This showed that EBAs and Rhs – but not MSP1 – affected merozoite attachment. Danny Wilson (University of Adelaide) reminded us of the diversity of MSPs and how these are grouped by localization, not necessarily function. He focused on three P. falciparum MSPs and their homologs in P. knowlesi and P. vivax, using knockout lines to determine which are essential, countering previous assumptions. Ross Waller (University of Cambridge) showed us how to use HyperLOPIT to determine the localization of parasite proteins, and how the technique can even dissect mechanisms of host cell remodeling by the parasite. No blood-stage session would be complete without var genes: first, Kirk Deitsch (Cornell University) described parasite populations which express multiple, single, or no var genes, and how these 'var-null' parasites can evade immune recognition and contribute to persistent, asymptomatic infections; we then heard from Tobias Spielmann (Bernhard Nocht Institute) about how selection-linked integration (SLI) can be used to force expression of specific var genes of interest in parasite culture, and how 3D7 may not always be the best line for investigating PfEMP1 binding in vitro. Michal Kucharski What can we do when genetic-based strategies for identifying new drug targets fail, and how can we find targets for irresistible drugs? Susan Wyllie (University of Dundee) started the session with an exciting dose of modern approaches to chemical proteomics strategies for direct target identification. By using a skillful combination of bait beads with polyethylene glycol (PEG)-linked compounds and thermal proteome profiling, she 'pulled' the audience into the world of malaria drug-target discovery. After an optimistic start, the next talk brought everyone back to the rapidly progressing reality of drug resistance. Deusdedith Ishengoma (National Institute for Medical Research) presented evidence confirming Tanzania as yet another African country with evidence of partial resistance to artemisinins, after Eritrea, Rwanda, and Uganda. The resistant parasites carried the R561H mutation in Kelch 13 (K13) gene and shared the same haplotypes with Rwandan strains but not those from South East Asia, suggesting an ongoing regional spread. As the spread of artemisinin resistance progresses through Africa, the next two talks were fitting. Belen Tornesi (Medicines for Malaria Venture) stressed the importance of Triple Combination Therapies (TCT) in the fight against drug resistance. She presented an optimized in vitro 'Interaction-Parasite Reduction Ratio Assay' designed to examine the parasite killing rate by TCTs. This is a much-needed tool on the way to develop a single-dose cure. Kelly Chibale (University of Cape Town) revealed a new compound series simultaneously targeting two distinct but highly Plasmodium-specific targets – the hemozoin formation pathway and parasite kinases. Two modes of action for a single molecule could offer great potential for reduced resistance risk. The closing talk by Ashley Vaughan (Seattle Children's Research Institute) 'Swift-ly' convinced everyone that well-'Taylor-ed' genetic crosses can be a powerful tool in searching for the genomic background of drug resistance. He showed that mutations in PfAA1 – a putative amino acid transporter – interacts with mutant PfCRT alleles to mediate both chloroquine resistance and parasite fitness. Interestingly, he also showed that plasmepsin II/III amplification enhanced piperaquine resistance in the presence of a novel G367C PfCRT mutation. Damian A. Oyong The immunity session provided exciting insights into how the human immune system responds to malaria. Gemma Moncunill (Barcelona Institute for Global Health) kicked off the session by showcasing some exciting findings on correlates of protection in the RTS,S/AS01 cohort. She identified circumsporozoite protein (CSP)-specific cell responses and transcriptomic signatures that were associated with vaccine-induced protection and highlighted the importance of immune status prior to vaccination. Next, Noah Butler (University of Iowa) described the mechanism by which Plasmodium infection skews B-cell differentiation into short-lived plasmablasts, acting as a glutamine (nutrient) sink that limits germinal center B-cell responses. He then demonstrated how glutamine impacts adaptive immune cells and their metabolic pathways. Brendan McMorran (Australian National University) presented on platelet factor 4 dimer internalization peptide (PDIP), a drug-like molecule with unique anti-plasmodial mechanisms and specific selectivity for intraerythrocytic parasites. Lynette Beattie (University of Melbourne) highlighted the critical role of γδ T cells against pre-erythrocytic malaria, acting through IFNγ and interleukin 4 (IL-4) secretion that provide help for dendritic cells to interact with CD4+ and CD8+ T cells. Gonzalo Acevedo (University of California, San Francisco) presented work identifying liver-specific P. falciparum antigen epitopes that bind to MHC-II, with antigen LISP1 broadly recognized by CD4+ T cells in a Ugandan child cohort. Hedda Wardemann (German Cancer Research Center/Bill and Melinda Gates Foundation) provided an in-depth view on strategies to improve adaptive immune responses to P. falciparum CSP (PfCSP). Using functional and molecular approaches, she identified specific regions within PfCSP that are immunodominant and targets of parasite inhibitory antibodies. Finally, Wiebke Nahrendorf (University of Edinburgh) gave a detailed view on mechanisms of disease tolerance in controlled human malaria re-challenge models. In the absence of anti-parasite immunity, a single P. falciparum infection induces host control of T cell activation and cytotoxicity, while P. vivax can quickly control systemic inflammation and fever. Heterologous P. falciparum re-challenge revealed that clinical immunity is species-specific. Julie M. J. Verhoef During sexual stage development, Plasmodium parasites prepare themselves for human-to-mosquito transmission, where they need to rapidly adjust to their environmental changes. Although this stage is crucial in malaria transmission, it remains poorly understood. Michaela Petter (University Hospital Erlangen) showed that BDP1 is an essential transcription regulator in gametocytes by modulating the repressive transcription factor AP2-03. Novel small-molecule inhibitors can target BDP1 and affect sexual and asexual parasites. Björn Kafsack (Weill Cornell Medicine) showed that opposing ends of the nuclear factor HDP1 are involved in two distinct functions, including gametocyte maturation beyond stage I, and formation and development of male gametocytes. Danushka Marapana (WEHI) characterized a Plasmodium E3 ligase complex, which is essential for gametocyte development and parasite transmission. He used a knockout approach to resolve the function of the different proteins forming this complex. Oliver Billker (University of Umeå) presented fertility screens that identified genes essential for Plasmodium berghei transmission. This gave many new insights in sex-specific protein functions and paves the way to identify new transmission blocking targets. Work from Rita Terwari (University of Nottingham) focused on characterization of kinases and their function during cell division. She showed that Nima like kinase 1 (NEK1) is essential for male gamete formation and coordinates microtubule organizing center (MTOC) organization and kinetochore attachment during mitosis. Scott Lindner (Pennsylvania State University) used comparative transcriptomics and proteomics across host-to-mosquito transmission to study global release of translational repression. Using TurboID on DOZI and ALBA4, he showed that 5′ and 3′ ends of mRNAs are close to each other during translational repression in female gametocytes, and then dissociate upon repression release in the zygotes. Gigliola Zanghi (Seattle Children's Research Institute) used a humanized mouse model and a novel fluorescent NF54 parasite line to study gene expression throughout liver stage development, finding many new insights including that P. falciparum liver stage parasites are not sexually committed. Esrah Du The talks in this session focused on various aspects of transmission: from potential novel interventions to the basic biology of transmission-stage parasite development. Flaminia Catteruccia (Harvard University) presented a novel in vivo screen of anti-malarial compounds in mosquito stages. This work identified 20 active compounds that inhibit parasite development within the mosquito, revealing essential parasite processes and pathways that can be targeted in mosquito-based malaria control strategies. Fiona Angrisano (Burnet Institute) identified a novel anti-gametocyte target, a protein disulfide isomerase (PDI-Trans). PDI inhibitors such as bacitracin and anti-PDI-Trans peptide antibodies both significantly reduced oocyst prevalence and intensity, revealing PDI-Trans to be a viable drug and vaccine target for blocking malaria transmission. Matthias Rottman (Swiss Tropical and Public Health Institute) presented a robust pipeline for the in vitro discovery and in vivo validation of P. falciparum malaria gametocytocidal and transmission blocking drugs, applying this system to evaluate the activity of several clinical drug candidates. This pipeline leveraged an engineered parasite line, enabling easy production of highly synchronous mature gametocytes expressing a red-shifted luciferase reporter combined with a P. falciparum humanized mouse model. Digging into the basic biology of mosquito-stage parasite development, Benjamin Liffner (Indiana University School of Medicine) utilized ultrastructural expansion microscopy to illustrate the process of establishment of apical polarity and rhoptry biogenesis in sporozoites, highlighting key differences in ultrastructure as they invade mosquito salivary glands. Lauriane Sollelis (University of Zurich) presented data from a genome-wide association study that identified a lncRNA (ben) as a genetic determinant of malaria transmission. She showed that alleles associated with high gametocyte production provide the background for artemisinin resistant K13 mutations in Southeast Asia, likely enabling the spread of the resistance trait. Sophie Collier (University of Melbourne) explored the uniparental mechanisms by which the mitochondria and apicoplast are inherited during P. berghei sexual reproduction. Using lattice light-sheet microscopy, it was determined that while activated female gametocytes retain an apicoplast and mitochondria, these organelles are excluded from male microgametes, confirming a maternal inheritance pattern. Elizabeth Villasis The session started with Matthew Higgins (University of Oxford), who shared with us new insights in the study of the PfPCRCR complex which seems to bridge the parasite and erythrocyte membrane during erythrocyte invasion. He also introduced new RH5-based immunogens, highlighting the strong inhibitory power of antibodies against a rationally-designed immunogen RH5.2 which has now been produced for evaluation in clinical trials. Next, Azza Idris (Ragon Institute) showed findings on two highly protective human monoclonal antibodies (mAbs) that target PfCSP epitopes not present in approved vaccines. The more clinically advanced CIS43LS provided 88.2% efficacy against malaria among adults in an endemic setting while Phase 2 trials for L9LS are currently underway. The use of mAbs, either alone or in combination with other interventions, is a promising approach to combat malaria. Liriye Kurtovic (Burnet Institute) showed us the impressive results of her work on the discovery of the role of anti-CSP IgA functional antibodies with binding capacity to Fcγα receptors as a potential protective mechanism induced by the RTS,S malaria vaccine in a pediatric Phase 2b clinical trial. Danielle Stanisic (Griffith University) showed the promising results of her work on the evaluation of chemically attenuated whole Pf blood-stage parasitized RBCs in malaria-naïve volunteers. Later, Krishanpal Karmodiya (Indian Institute of Science Education and Research) demonstrated that vaccination with three chimeric antigens targeting eight PfEMP1 proteins (chimeric var B) and eight merozoite surface proteins (chimeric MSP and InvP) effectively reduced P. falciparum cytoadhesion and inhibited parasite growth in vitro. Finally, Justin Boddey (WEHI) presented interesting results from an academic–industrial collaboration with MERCK (MSD) on the evaluation of anti-malarial drugs against the late liver-stage as a seasonal malaria chemoprevention that also induces immunity. He showed that Plasmepsin IX/X dual inhibitors kill liver merozoites and prevent blood-stage infection using P. berghei and P. falciparum mouse models and can provide up to 19 months of sterile immunity against P. berghei mosquito re-infection in mice. Kioko Mwikali Malaria parasites can cause severe disease syndromes, including cerebral malaria, severe malaria anemia, and respiratory distress. However, the host and parasite mechanisms contributing to severe disease are not fully understood. Ana Rodriguez (New York University) started the pathogenesis session by showing that anti-phosphatidylserine (PS) antibodies produced by atypical B cells during malaria infection mediate phagocytosis of unparasitized erythrocytes exposing PS, which could lead to severe malaria anemia. Ana further went on to reveal that infected erythrocytes and not tumor necrosis factor (TNF)α disrupt the blood–brain barrier (BBB) during cerebral malaria. On the same theme, Hannah Fleckenstein (EMBL Barcelona) presented elegant 3D volume electron microscope images of interactions between infected erythrocytes and endothelial cells in 3D in vitro BBB models. She showed how endothelial cells actively remodel their cytoskeleton to increase the surface interaction with infected erythrocytes. Tracey Lamb (University of Utah) presented immunological data suggesting that a population of CD8+ T cells skewed towards low-affinity receptors is strongly associated with the breakdown of the BBB. On a different theme, Steven Kho (Menzies School of Health Research) mesmerized the audience by presenting data showing that the splenic biomass of both P. vivax and P. falciparum was greater than the peripheral biomass. However, Lauren Galloway (University of Glasgow) later showed that parasite densities, rather than biomass, were higher in the spleen than in other tissues, while gametocytes were sequestered primarily in the bone marrow rather than the spleen. The session took a rather unexpected turn when Nathan Schmidt (Indiana University School of Medicine) presented data from human cross-sectional studies and mouse models linking gut bacteria from the Bacteroides genus to severe malaria outcomes. Finally, Rhea Longley (WEHI) ended the session by revealing a serological tool called PvSeroTAT that can accurately identify recent exposure and individuals with hypnozoites.
Longley et al. (Fri,) studied this question.