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The chromatin-associated protein WDR5 has been widely studied due to its role in histone modification and its potential as a pharmacological target for the treatment of cancer. In humans, the protein with highest sequence homology to WDR5 is encoded by the retrogene WDR5B, which remains unexplored. Here, we used CRISPR-Cas9 genome editing to generate WDR5B knockout and WDR5B-FLAG knock-in cell lines for further characterization. In contrast to WDR5, WDR5B exhibits low expression in pluripotent cells and is upregulated upon neural differentiation. Loss or shRNA depletion of WDR5B impairs cell growth and increases the fraction of non-viable cells in proliferating retinal pigment epithelial (RPE) cultures. CUT&RUN chromatin profiling in RPE and neural progenitors indicates minimal WDR5B enrichment at established WDR5 binding sites. These results suggest that WDR5 and WDR5B exhibit several divergent biological properties despite sharing a high degree of sequence homology.

Malaria transmission depends on the presence of Plasmodium gametocytes that are the only parasite life stage that can infect mosquitoes. Gametocyte production varies between infections and over the course of infections. Infection duration is highly important for gametocyte production but poorly quantified. Between 2017 and 2019 an all-age cohort of individuals from Tororo, eastern Uganda was followed by continuous passive and routine assessments. We longitudinally monitored 104 incident infections from 98 individuals who were sampled once every 28 days and on any day of symptoms. Among infections that lasted ≥ 3 months, gametocyte appearance was near-universal with 96% of infections having detectable gametocytes prior to clearance. However, most infections were of much shorter duration; 55.7% of asymptomatic infections were detected only once. When considering all asymptomatic infections, regardless of their duration, only 36.3% had detectable gametocytes on at least one time-point prior to parasite clearance. Infections in individuals with sickle-cell trait (HbAS) were more likely to have gametocytes detected (Hazard Rate (HR) = 2.68, 95% CI 1.12, 6.38; p = 0.0231) and had gametocytes detected at higher densities (Density Ratio (DR) = 9.19, 95% CI 2.79, 30.23; p = 0.0002) compared to infections in wildtype (HbAA) individuals. Our findings suggest that a large proportion of incident infections is too short in duration and of too low density to contribute to onward transmission.

The proteasome is a promising target for antimalarial chemotherapy. We assessed ex vivo susceptibilities of fresh Plasmodium falciparum isolates from eastern Uganda to seven proteasome inhibitors: two asparagine ethylenediamines, two macrocyclic peptides, and three peptide boronates; five had median IC50 values

Dry age-related macular degeneration (AMD) is estimated to impact nearly 300 million individuals globally by 2040. While no treatment options are currently available, multiple clinical trials investigating retinal pigmented epithelial cells derived from human pluripotent stem cells (hPSC-RPE) as a cellular replacement therapeutic are currently underway. It has been estimated that a production capacity of >109 RPE cells annually would be required to treat the afflicted population, but current manufacturing protocols are limited, being labor-intensive and time-consuming. Microcarrier technology has enabled high-density propagation of many adherent mammalian cell types via monolayer culture on surfaces of uM-diameter matrix spheres; however, few studies have explored microcarrier-based culture of RPE cells. Here, we provide an approach to the growth, maturation, and differentiation of hPSC-RPE cells on Cytodex 1 (C1) and Cytodex 3 (C3) microcarriers. We demonstrate that hPSC-RPE cells adhere to microcarriers coated with Matrigel, vitronectin or collagen, and mature in vitro to exhibit characteristic epithelial cell morphology and pigmentation. Microcarrier-grown hPSC-RPE cells (mcRPE) are viable; metabolically active; express RPE signature genes including BEST1, RPE65, TYRP1, and PMEL17; secrete the trophic factors PEDF and VEGF; and demonstrate phagocytosis of photoreceptor outer segments. Furthermore, we show that undifferentiated hESCs also adhere to Matrigel-coated microcarriers and are amenable to directed RPE differentiation. The capacity to support hPSC-RPE cell cultures using microcarriers enables efficient large-scale production of therapeutic RPE cells sufficient to meet the treatment demands of a large AMD patient population.

BACKGROUND: Targeted next-generation sequencing offers the potential for consistent, deep coverage of information-rich genomic regions to characterize polyclonal Plasmodium falciparum infections. However, methods to identify and sequence these genomic regions are currently limited. METHODS: A bioinformatic pipeline and multiplex methods were developed to identify and simultaneously sequence 100 targets and applied to dried blood spot (DBS) controls and field isolates from Mozambique. For comparison, whole-genome sequencing data were generated for the same controls. RESULTS: Using publicly available genomes, 4465 high-diversity genomic regions suited for targeted sequencing were identified, representing the P. falciparum heterozygome. For this study, 93 microhaplotypes with high diversity (median expected heterozygosity = 0.7) were selected along with 7 drug resistance loci. The sequencing method achieved very high coverage (median 99%), specificity (99.8%), and sensitivity (90% for haplotypes with 5% within sample frequency in dried blood spots with 100 parasites/µL). In silico analyses revealed that microhaplotypes provided much higher resolution to discriminate related from unrelated polyclonal infections than biallelic single-nucleotide polymorphism barcodes. CONCLUSIONS: The bioinformatic and laboratory methods outlined here provide a flexible tool for efficient, low-cost, high-throughput interrogation of the P. falciparum genome, and can be tailored to simultaneously address multiple questions of interest in various epidemiological settings.

BackgroundThe Plasmodium falciparum dihydrofolate reductase (PfDHFR) inhibitors pyrimethamine and cycloguanil (the active metabolite of proguanil) have important roles in malaria chemoprevention, but drug resistance challenges their efficacies. A new compound, P218, was designed to overcome resistance, but drug-susceptibility data for P falciparum field isolates are limited.MethodsWe studied ex vivo PfDHFR inhibitor susceptibilities of 559 isolates from Tororo and Busia districts, Uganda, from 2016 to 2020, sequenced 383 isolates, and assessed associations between genotypes and drug-susceptibility phenotypes.ResultsMedian half-maximal inhibitory concentrations (IC50s) were 42 100 nM for pyrimethamine, 1200 nM for cycloguanil, 13000 nM for proguanil, and 0.6 nM for P218. Among sequenced isolates, 3 PfDHFR mutations, 51I (100%), 59R (93.7%), and 108N (100%), were very common, as previously seen in Uganda, and another mutation, 164L (12.8%), had moderate prevalence. Increasing numbers of mutations were associated with decreasing susceptibility to pyrimethamine, cycloguanil, and P218, but not proguanil, which does not act directly against PfDHFR. Differences in P218 susceptibilities were modest, with median IC50s of 1.4 nM for parasites with mixed genotype at position 164 and 5.7 nM for pure quadruple mutant (51I/59R/108N/164L) parasites.ConclusionsResistance-mediating PfDHFR mutations were common in Ugandan isolates, but P218 retained excellent activity against mutant parasites.

Artemisinin partial resistance may facilitate selection of Plasmodium falciparum resistant to combination therapy partner drugs. We evaluated 99 P. falciparum isolates collected in 2021 from northern Uganda, where resistance-associated PfK13 C469Y and A675V mutations have emerged, and eastern Uganda, where these mutations are uncommon. With the ex vivo ring survival assay, isolates with the 469Y mutation (median survival 7.3% for mutant, 2.5% mixed, and 1.4% wild type) and/or mutations in Pfcoronin or falcipain-2a, had significantly greater survival; all isolates with survival >5% had mutations in at least one of these proteins. With ex vivo growth inhibition assays, susceptibility to lumefantrine (median IC50 14.6 vs. 6.9 nM, p  20 nM (p = 0.0002). Targeted sequencing of 819 isolates from 2015-21 identified multiple polymorphisms associated with altered drug susceptibility, notably PfK13 469Y with decreased susceptibility to lumefantrine (p = 6 × 10-8) and PfCRT mutations with chloroquine resistance (p = 1 × 10-20). Our results raise concern regarding activity of artemether-lumefantrine, the first-line antimalarial in Uganda.

PURPOSE: To report 1-year follow-up of a phase 1/2a clinical trial testing a composite subretinal implant having polarized human embryonic stem cell (hESC)-derived retinal pigment epithelium (RPE) cells on an ultrathin parylene substrate in subjects with advanced non-neovascular age-related macular degeneration (NNAMD). METHODS: The phase 1/2a clinical trial included 16 subjects in two cohorts. The main endpoint was safety assessed at 365 days using ophthalmic and systemic exams. Pseudophakic subjects with geographic atrophy (GA) and severe vision loss were eligible. Low-dose tacrolimus immunosuppression was utilized for 68 days in the peri-implantation period. The implant was delivered to the worst seeing eye with a custom subretinal insertion device in an outpatient setting. A data safety monitoring committee reviewed all results. RESULTS: The treated eyes of all subjects were legally blind with a baseline best-corrected visual acuity (BCVA) of ≤ 20/200. There were no unexpected serious adverse events. Four subjects in cohort 1 had serious ocular adverse events, including retinal hemorrhage, edema, focal retinal detachment, or RPE detachment, which was mitigated in cohort 2 using improved hemostasis during surgery. Although this study was not powered to assess efficacy, treated eyes from four subjects showed an increased BCVA of >5 letters (6-13 letters). A larger proportion of treated eyes experienced a >5-letter gain when compared with the untreated eye (27% vs. 7%; P = not significant) and a larger proportion of nonimplanted eyes demonstrated a >5-letter loss (47% vs. 33%; P = not significant). CONCLUSIONS: Outpatient delivery of the implant can be performed routinely. At 1 year, the implant is safe and well tolerated in subjects with advanced dry AMD. TRANSLATIONAL RELEVANCE: This work describes the first clinical trial, to our knowledge, of a novel implant for advanced dry AMD.

BackgroundIn Uganda, artemether-lumefantrine is recommended for malaria treatment and sulfadoxine-pyrimethamine for chemoprevention during pregnancy, but drug resistance may limit efficacies.MethodsGenetic polymorphisms associated with sensitivities to key drugs were characterized in samples collected from 16 sites across Uganda in 2018 and 2019 by ligase detection reaction fluorescent microsphere, molecular inversion probe, dideoxy sequencing, and quantitative polymerase chain reaction assays.ResultsConsidering transporter polymorphisms associated with resistance to aminoquinolines, the prevalence of Plasmodium falciparum chloroquine resistance transporter (PfCRT) 76T decreased, but varied markedly between sites (0-46% in 2018; 0-23% in 2019); additional PfCRT polymorphisms and plasmepsin-2/3 amplifications associated elsewhere with resistance to piperaquine were not seen. For P. falciparum multidrug resistance protein 1, in 2019 the 86Y mutation was absent at all sites, the 1246Y mutation had prevalence ≤20% at 14 of 16 sites, and gene amplification was not seen. Considering mutations associated with high-level sulfadoxine-pyrimethamine resistance, prevalences of P. falciparum dihydrofolate reductase 164L (up to 80%) and dihydropteroate synthase 581G (up to 67%) were high at multiple sites. Considering P. falciparum kelch protein propeller domain mutations associated with artemisinin delayed clearance, prevalence of the 469Y and 675V mutations has increased at multiple sites in northern Uganda (up to 23% and 41%, respectively).ConclusionsWe demonstrate concerning spread of mutations that may limit efficacies of key antimalarial drugs.

Age-related macular degeneration (AMD) is the primary cause of blindness in adults over 60 years of age, and clinical trials are currently assessing the therapeutic potential of retinal pigmented epithelial (RPE) cell monolayers on implantable scaffolds to treat this disease. However, challenges related to the culture, long-term storage, and long-distance transport of such implants currently limit the widespread use of adherent RPE cells as therapeutics. Here we report a xeno-free protocol to cryopreserve a confluent monolayer of clinical-grade, human embryonic stem cell-derived RPE cells on a parylene scaffold (REPS) that yields viable, polarized, and functional RPE cells post-thaw. Thawed cells exhibit ≥ 95% viability, have morphology, pigmentation, and gene expression characteristic of mature RPE cells, and secrete the neuroprotective protein, pigment epithelium-derived factor (PEDF). Stability under liquid nitrogen (LN2) storage has been confirmed through one year. REPS were administered immediately post-thaw into the subretinal space of a mammalian model, the Royal College of Surgeons (RCS)/nude rat. Implanted REPS were assessed at 30, 60, and 90 days post-implantation, and thawed cells demonstrate survival as an intact monolayer on the parylene scaffold. Furthermore, immunoreactivity for the maturation marker, RPE65, significantly increased over the post-implantation period in vivo, and cells demonstrated functional attributes similar to non-cryopreserved controls. The capacity to cryopreserve adherent cellular therapeutics permits extended storage and stable transport to surgical sites, enabling broad distribution for the treatment of prevalent diseases such as AMD.

Artemether-lumefantrine (AL) is a first-line agent for uncomplicated malaria caused by Plasmodium falciparum. The WHO recommends periodic therapeutic efficacy studies of antimalarial drugs for the detection of malaria parasite drug resistance and to inform national malaria treatment policies. We conducted a therapeutic efficacy study of AL in a high malaria transmission region of northern Zambia from December 2014 to July 2015. One hundred children of ages 6 to 59 months presenting to a rural health clinic with uncomplicated falciparum malaria were admitted for treatment with AL (standard 6-dose regimen) and followed weekly for 5 weeks. Parasite counts were taken every 6 hours during treatment to assess parasite clearance. Recurrent episodes during follow-up (n = 14) were genotyped to distinguish recrudescence from reinfection and to identify drug resistance single nucleotide polymorphisms (SNPs) and multidrug resistance protein 1 (mdr1) copy number variation. Day 7 lumefantrine concentrations were measured for correspondence with posttreatment reinfection. All children who completed the parasite clearance portion of the study (n = 94) were microscopy-negative by 72 hours. The median parasite elimination half-life was 2.7 hours (interquartile range: 2.1-3.3). Genotype-corrected therapeutic efficacy was 98.8% (95% CI: 97.6-100). Purported artemisinin and lumefantrine drug resistance SNPs in atp6, 3D7_1451200, and mdr1 were detected but did not correlate with parasite recurrence, nor did day 7 lumefantrine concentrations. In summary, AL was highly effective for the treatment of uncomplicated falciparum malaria in northern Zambia during the study period. The high incidence of recurrent parasitemia was consistent with reinfection due to high, perennial malaria transmission.

This research study surveyed 100 undergraduate teacher education students in a regional university in Australia, explored self-reported perceptions of their knowledge about students with exceptional needs, and their competence to be effective educators of these students in an inclusive classroom. Additionally, we included a measure of general attitude toward teaching in an inclusive classroom. What made this exploratory study atypical was broadening the concept of 'exceptionality' to the inclusion of items related to students with physical and cognitive challenges, superior academic gifts and those deemed to be twice exceptional. The results were unexpected in that teachers' age, parental status and exposure to units of study in special and inclusive education did not differentiate their knowledge, perceived competence, or general attitude.

Retinal pigment epithelial (RPE) cells are exclusive to the retina, critically multifunctional in maintaining the visual functions and health of photoreceptors and the retina. Despite their vital functions throughout lifetime, RPE cells lack regenerative capacity, rendering them vulnerable which can lead to degenerative retinal diseases. With advancements in stem cell technology enabling the differentiation of functional cells from pluripotent stem cells and leveraging the robust autocrine and paracrine functions of RPE cells, extracellular vesicles (EVs) secreted by RPE cells hold significant therapeutic potential in supplementing RPE cell activity. While previous research has primarily focused on the trophic factors secreted by RPE cells, there is a lack of studies investigating miRNA, which serves as a master regulator of gene expression. Profiling and defining the functional role of miRNA contained within RPE‐secreted EVs is critical as it constitutes a necessary step in identifying the optimal phenotype of the EV‐secreting cell and understanding the biological cargo of EVs to develop EV‐based therapeutics. In this study, we present a comprehensive profile of miRNA in small extracellular vesicles (sEVs) secreted during RPE maturation following differentiation from human embryonic stem cells (hESCs); early‐stage hESC‐RPE (20–21 days in culture), mid‐stage hESC‐RPE (30–31 days in culture) and late‐stage hESC‐RPE (60–61 days in culture). This exploration is essential for ongoing efforts to develop and optimize EV‐based intraocular therapeutics utilizing RPE‐secreted EVs, which may significantly impact the function of dysfunctional RPE cells in retinal diseases. [ABSTRACT FROM AUTHOR]

Newly arrived refugees offer insights into malaria epidemiology in their countries of origin. We evaluated asymptomatic refugee children within 7 days of arrival in Uganda from South Sudan and the Democratic Republic of Congo (DRC) in 2022 for parasitemia, parasite species, and Plasmodium falciparum drug resistance markers. Asymptomatic P. falciparum infections were common in both populations. Coinfection with P. malariae was more common in DRC refugees. Prevalences of markers of aminoquinoline resistance (PfCRT K76T, PfMDR1 N86Y) were much higher in South Sudan refugees, of antifolate resistance (PfDHFR C59R and I164L, PfDHPS A437G, K540E, and A581G) much higher in DRC refugees, and of artemisinin partial resistance (ART-R; PfK13 C469Y and A675V) moderate in both populations. Prevalences of most mutations differed from those seen in Ugandans attending health centers near the refugee centers. Refugee evaluations yielded insights into varied malaria epidemiology and identified markers of ART-R in 2 previously little-studied countries. [ABSTRACT FROM AUTHOR]

A better understanding of the drivers of the spread of malaria parasites and drug resistance across space and time is needed. These drivers can be elucidated using genetic tools. Here, a novel molecular inversion probe (MIP) panel targeting all major drug-resistance mutations and a set of microsatellites was used to genotype Plasmodium falciparum infections of 552 children from the 2013-2014 Demographic and Health Survey conducted in the Democratic Republic of the Congo (DRC). Microsatellite-based analysis of population structure suggests that parasites within the DRC form a homogeneous population. In contrast, sulfadoxine-resistance markers in dihydropteroate synthase show marked spatial structure with ongoing spread of double and triple mutants compared with 2007. These findings suggest that parasites in the DRC remain panmictic despite rapidly spreading antimalarial-resistance mutations. Moreover, highly multiplexed targeted sequencing using MIPs emerges as a cost-effective method for elucidating pathogen genetics in complex infections in large cohorts.