A tryptophan metabolite made by a gut microbiome eukaryote induces pro-inflammatory T cells.

The large intestine harbors microorganisms playing unique roles in host physiology. The beneficial or detrimental outcome of host-microbiome coexistence depends largely on the balance between regulators and responder intestinal CD4+ T cells. We found that ulcerative colitis-like changes in the large intestine after infection with the protist Blastocystis ST7 in a mouse model are associated with reduction of anti-inflammatory Treg cells and simultaneous expansion of pro-inflammatory Th17 responders. These alterations in CD4+ T cells depended on the tryptophan metabolite indole-3-acetaldehyde (I3AA) produced by this single-cell eukaryote. I3AA reduced the Treg subset in vivo and iTreg development in vitro by modifying their sensing of TGFß, concomitantly affecting recognition of self-flora antigens by conventional CD4+ T cells. Parasite-derived I3AA also induces over-exuberant TCR signaling, manifested by increased CD69 expression and downregulation of co-inhibitor PD-1. We have thus identified a new mechanism dictating CD4+ fate decisions. The findings thus shine a new light on the ability of the protist microbiome and tryptophan metabolites, derived from them or other sources, to modulate the adaptive immune compartment, particularly in the context of gut inflammatory disorders.

Informing policy via dynamic models: Cholera in Haiti.

Public health decisions must be made about when and how to implement interventions to control an infectious disease epidemic. These decisions should be informed by data on the epidemic as well as current understanding about the transmission dynamics. Such decisions can be posed as statistical questions about scientifically motivated dynamic models. Thus, we encounter the methodological task of building credible, data-informed decisions based on stochastic, partially observed, nonlinear dynamic models. This necessitates addressing the tradeoff between biological fidelity and model simplicity, and the reality of misspecification for models at all levels of complexity. We assess current methodological approaches to these issues via a case study of the 2010-2019 cholera epidemic in Haiti. We consider three dynamic models developed by expert teams to advise on vaccination policies. We evaluate previous methods used for fitting these models, and we demonstrate modified data analysis strategies leading to improved statistical fit. Specifically, we present approaches for diagnosing model misspecification and the consequent development of improved models. Additionally, we demonstrate the utility of recent advances in likelihood maximization for high-dimensional nonlinear dynamic models, enabling likelihood-based inference for spatiotemporal incidence data using this class of models. Our workflow is reproducible and extendable, facilitating future investigations of this disease system.

Four-dimensional chromosome reconstruction elucidates the spatiotemporal reorganization of the mammalian X chromosome.

Chromosomes are segmented into domains and compartments, but how these structures are spatially related in three dimensions (3D) is unclear. Here, we developed tools that directly extract 3D information from Hi-C experiments and integrate the data across time. With our "4DHiC" method, we use X chromosome inactivation (XCI) as a model to examine the time evolution of 3D chromosome architecture during large-scale changes in gene expression. Our modeling resulted in several insights. Both A/B and S1/S2 compartments divide the X chromosome into hemisphere-like structures suggestive of a spatial phase-separation. During the XCI, the X chromosome transits through A/B, S1/S2, and megadomain structures by undergoing only partial mixing to assume new structures. Interestingly, when an active X chromosome (Xa) is reorganized into an inactive X chromosome (Xi), original underlying compartment structures are not fully eliminated within the Xi superstructure. Our study affirms slow mixing dynamics in the inner chromosome core and faster dynamics near the surface where escapees reside. Once established, the Xa and Xi resemble glassy polymers where mixing no longer occurs. Finally, Xist RNA molecules initially reside within the A compartment but transition to the interface between the A and B hemispheres and then spread between hemispheres via both surface and core to establish the Xi.

New insights into the interactions between Blastocystis, the gut microbiota, and host immunity.

The human gut microbiota is a diverse and complex ecosystem that is involved in beneficial physiological functions as well as disease pathogenesis. Blastocystis is a common protistan parasite and is increasingly recognized as an important component of the gut microbiota. The correlations between Blastocystis and other communities of intestinal microbiota have been investigated, and, to a lesser extent, the role of this parasite in maintaining the host immunological homeostasis. Despite recent studies suggesting that Blastocystis decreases the abundance of beneficial bacteria, most reports indicate that Blastocystis is a common component of the healthy gut microbiome. This review covers recent finding on the potential interactions between Blastocystis and the gut microbiota communities and its roles in regulating host immune responses.

Null results of oxytocin and vasopressin administration on mentalizing in a large fMRI sample: evidence from a randomized controlled trial.

BACKGROUND: Although potential links between oxytocin (OT), vasopressin (AVP), and social cognition are well-grounded theoretically, most studies have included all male samples, and few have demonstrated consistent effects of either neuropeptide on mentalizing (i.e. understanding the mental states of others). To understand the potential of either neuropeptide as a pharmacological treatment for individuals with impairments in social cognition, it is important to demonstrate the beneficial effects of OT and AVP on mentalizing in healthy individuals. METHODS: In the present randomized, double-blind, placebo-controlled study (n = 186) of healthy individuals, we examined the effects of OT and AVP administration on behavioral responses and neural activity in response to a mentalizing task. RESULTS: Relative to placebo, neither drug showed an effect on task reaction time or accuracy, nor on whole-brain neural activation or functional connectivity observed within brain networks associated with mentalizing. Exploratory analyses included several variables previously shown to moderate OT's effects on social processes (e.g., self-reported empathy, alexithymia) but resulted in no significant interaction effects. CONCLUSIONS: Results add to a growing literature demonstrating that intranasal administration of OT and AVP may have a more limited effect on social cognition, at both the behavioral and neural level, than initially assumed. Randomized controlled trial registrations: ClinicalTrials.gov; NCT02393443; NCT02393456; NCT02394054.

Experimental colonization with Blastocystis ST4 is associated with protective immune responses and modulation of gut microbiome in a DSS-induced colitis mouse model.

BACKGROUND: Blastocystis is a common gut protistan parasite in humans and animals worldwide, but its interrelationship with the host gut microbiota and mucosal immune responses remains poorly understood. Different murine models of Blastocystis colonization were used to examine the effect of a common Blastocystis subtype (ST4) on host gut microbial community and adaptive immune system. RESULTS: Blastocystis ST4-colonized normal healthy mice and Rag1-/- mice asymptomatically and was able to alter the microbial community composition, mainly leading to increases in the proportion of Clostridia vadinBB60 group and Lachnospiraceae NK4A136 group, respectively. Blastocystis ST4 colonization promoted T helper 2 (Th2) response defined by interleukin (IL)-5 and IL-13 cytokine production, and T regulatory (Treg) induction from colonic lamina propria in normal healthy mice. Additionally, we observed that Blastocystis ST4 colonization can maintain the stability of bacterial community composition and induce Th2 and Treg immune responses to promote faster recovery from experimentally induced colitis. Furthermore, fecal microbiota transplantation of Blastocystis ST4-altered gut microbiome to colitis mice reduced the severity of colitis, which was associated with increased production of short-chain fat acids (SCFAs) and anti-inflammatory cytokine IL-10. CONCLUSIONS: The data confirm our hypothesis that Blastocystis ST4 is a beneficial commensal, and the beneficial effects of Blastocystis ST4 colonization is mediated through modulating of the host gut bacterial composition, SCFAs production, and Th2 and Treg responses in different murine colonization models.

Facilities, selection, outcome measurement, and limitations of therapeutic plasma exchange for neuroimmunological disorders: The South East Asian survey study.

INTRODUCTION: Therapeutic plasma exchange (TPE) for neuroimmunological disorders has played an important role in the Southeast Asian region. This study investigates the challenges of performing TPE within the region. METHOD: A questionnaire-based survey was conducted and launched to 15 South East Asian Therapeutic Plasma Exchange Consortium (SEATPEC) members from seven countries in January 2021. It included demographics, TPE techniques, indications, challenges, timing, outcome measurement, and access to laboratory testing in each local center. RESULTS: A total of 15 neurologists from 12 participating centers were included. They usually perform five sessions of TPE (100.0%), with 1 to 1.5 plasma volume (93.3%), and exchanges via the central catheter (100.0%). Acute relapses of neuromyelitis optica spectrum disorder and myasthenia gravis are the most common indications. They used a combination of normal saline and 5% albumin (60.0%) as replacement fluid. Most (66.7%) used TPE as an add-on treatment in steroid-refractory cases or as first-line treatment for severe attacks. They suggested assessing the TPE efficacy of TPE by the interval to the next attack, post-TPE relapse rates, and TPE-related complications. The major challenges within our region are expense, reimbursibility, and access to TPE. CONCLUSION: Although countrywise differences exist, all share similarities regarding methods, indications, timing, obstacles, and challenges of TPE for neuroimmunological conditions. Regional collaboration will be essential to identify strategies to reduce these barriers to access to TPE in the future.

Resistance of Blastocystis to chlorine and hydrogen peroxide.

Blastocystis is a ubiquitous, widely distributed protist inhabiting the gastrointestinal tract of humans and other animals. The organism is genetically diverse, and so far, at least 28 subtypes (STs) have been identified with ST1-ST9 being the most common in humans. The pathogenicity of Blastocystis is controversial. Several routes of transmission have been proposed including fecal-oral (e.g., zoonotic, anthroponotic) and waterborne. Research on the latter has gained traction in the last few years with the organism having been identified in various bodies of water, tap water, and rainwater collection containers including water that has been previously filtered and/or chlorinated. Herein, we assessed the resistance of 11 strains maintained in culture, spanning ST1-ST9 to various chlorine and hydrogen peroxide concentrations for 24 h, and performed recovery assays along with re-exposure. Following the treatment with both compounds, all subtypes showed increased resistance, and viability could be visualized at the cellular level. These results are hinting at the presence of mechanism of resistance to both chlorine and hydrogen peroxide. As such, this pilot study can be the platform for developing guidelines for water treatment processes.

How community and organizational culture interact and affect senior clinical educator identity.

PURPOSE: The development of Educator Identity has a significant impact on well-being, motivation, productivity, and the quality of teaching. Previous research has shown that conflicting responsibilities and a challenging work environment could negatively affect the development of Clinical Educator Identity within an organization. However, there is a lack of research that identifies the factors affecting Clinical Educator Identity Formation and provides guidance on how organizations can support its development, maintenance, and advancement. METHODS: To examine the phenomenology of Professional Identity Development in experienced Senior Clinical Educators in Singaporean hospitals, the study utilized an exploratory qualitative approach. The data was collected from September 2021 to May 2022 through one-to-one interviews. Four investigators analyzed the data using constant comparative analysis to identify relevant themes. RESULTS: Eleven senior educators revealed that personal, relational, and organizational factors influenced the development of Clinical Educator Identity. The relational aspect was a vital enabler, while organizational culture was a strong barrier. The study also identified several ways in which organizations can support Educator Identity development. CONCLUSION: The study findings provide insight into how organizations can support the development of Clinical Educator Identity. The results could aid organizations in understanding the areas where they can channel resources to support Clinical Educator Identity development.

Is Virtual Team-Based Learning Feasible and Effective in Teaching Neurolocalisation?

We investigated the feasibility and effectiveness of virtual team-based learning (TBL) in teaching neurolocalisation (NL) in a sample of 18 student volunteers. Student satisfaction and knowledge outcomes were evaluated using the modified TBL Student Assessment Instrument and Extended Matching Questionnaire (EMQ), respectively. Mean student satisfaction rating was good at 3.9 out of 5.0 (SD 0.3). Participants achieved high mean EMQ scores of 84.2% (SD 2.9) with moderate correlation between individual assessment scores and EMQ scores (ρ = 0.587, p = 0.01). Virtual TBL is feasible for teaching NL with good student satisfaction and knowledge outcomes.

Should Aquaporin-4 Antibody Test Be Performed in all Patients With Isolated Optic Neuritis?

BACKGROUND: Optic neuritis (ON) may be the initial manifestation of neuromyelitis optica spectrum disorder (NMOSD). Aquaporin-4 antibody (AQP4 Ab) is used to diagnose NMOSD. This has implications on prognosis and is important for optimal management. We aim to evaluate if clinical features can distinguish AQP4 Ab seropositive and seronegative ON patients. METHODS: We reviewed patients with first episode of isolated ON from Tan Tock Seng Hospital and Singapore National Eye Centre who tested for AQP4 Ab from 2008 to 2017. Demographic and clinical data were compared between seropositive and seronegative patients. RESULTS: Among 106 patients (120 eyes) with first episode of isolated ON, 23 (26 eyes; 22%) were AQP4 Ab positive and 83 (94 eyes; 78%) were AQP4 Ab negative. At presentation, AQP4 Ab positive patients had older mean onset age (47.9 ± 13.6 vs 36.8 ± 12.6 years, P < 0.001), worse nadir VA (OR 1.714; 95% CI, 1.36 to 2.16; P < 0.001), less optic disc swelling (OR 5.04; 95% CI, 1.682 to 15.073; p = 0.004), and higher proportions of concomitant anti-Ro antibody (17% vs 4%, p = 0.038) and anti-La antibody (17% vs 1%, p = 0.008). More AQP4 Ab positive patients received steroid-sparing immunosuppressants (74% vs 19%, p < 0.001) and plasma exchange (13% vs 0%, p = 0.009). AQP4 Ab positive patients had worse mean logMAR VA (visual acuity) at 12 months (0.70 ± 0.3 vs 0.29 ± 0.5, p = 0.051) and 36 months (0.37±0.4 vs 0.14 ± 0.2, p = 0.048) follow-up. CONCLUSION: Other than older onset age and retrobulbar optic neuritis, clinical features are non-discriminatory for NMOSD. We propose a low threshold for AQP4 Ab serology testing in inflammatory ON patients, particularly in high NMOSD prevalence populations, to minimize diagnostic and treatment delays.

Viewing interprofessional collaboration through the lens of networked ecological systems theory.

Interprofessional collaboration (IPC) is key to ensuring safe quality care for patients. However, IPC intervention outcomes are variable, leading to calls for systems theories to understand complex interactions in healthcare. Using networked ecological systems theory (NEST), we aimed to uncover facilitators and barriers impacting the interactions between nurses and physicians in a specialty healthcare center. A qualitative study involving 55 non-participant observations and 17 individual semi-structured interviews was conducted at the National Neuroscience Institute of Singapore from April 2019 to March 2021. Template analysis was used to analyze the data. The most important IPC facilitators were exosystemic institutional support and physicians' willingness to engage in IPC in the microsystems that together enabled the establishment of disease-based outpatient programs fostering patient-centered interactions among different healthcare professionals (HCP). We also found that patient-, disease-, and systems-related knowledge played an important role in facilitating IPC. Macrosystemic entrenchments such as intraprofessional composition of ward rounds emerged as a significant barrier. However, microsystemic efforts such as chat groups connecting all HCP involved in the care of the patients in the wards have fostered IPC. Although still preliminary, these findings suggest NEST can be useful to inform systematic interventions to improve IPC.

Urban-Soil Pedogenesis Drives Contrasting Legacies of Lead from Paint and Gasoline in City Soil.

This study analyzed the impact of urban-soil pedogenesis on soil lead (Pb) contamination from paint and gasoline in the historic core of Durham, North Carolina. Total soil Pb in 1000 samples from streetsides, residential properties, and residual upland and floodplains ranged from 6 to 8825 mg/kg (mean = 211 mg/kg), with 50% of samples between 50 and 200 mg/kg soil Pb. The highest Pb concentrations were within 1 m of pre-1978 residential foundations, with concentrations inversely correlated with house age. Streetside soil Pb concentrations were elevated over the geologic background of <30 mg/kg and correlated with traffic flow. Streetside soil Pb concentrations were lower than Durham streetside soils collected in the 1970s, which was attributed to urban pedogenesis, the complex of natural and human processes that change soils over time. Accelerated erosion redistributes legacy Pb and floodplain sampling indicates sedimentation rates of up to 4 mm/year. Mixing and burial of soil with elevated Pb are also lowering soil Pb concentrations over time. These mechanisms are likely of greater significance on streetsides than near foundation soils. The development of an urban-pedogenesis framework can help guide public health approaches to Pb exposure by incorporating pedogenic processes that reduce and dissipate soil Pb contamination.

Lineage-negative progenitors mobilize to regenerate lung epithelium after major injury.

Broadly, tissue regeneration is achieved in two ways: by proliferation of common differentiated cells and/or by deployment of specialized stem/progenitor cells. Which of these pathways applies is both organ- and injury-specific. Current models in the lung posit that epithelial repair can be attributed to cells expressing mature lineage markers. By contrast, here we define the regenerative role of previously uncharacterized, rare lineage-negative epithelial stem/progenitor (LNEP) cells present within normal distal lung. Quiescent LNEPs activate a ΔNp63 (a p63 splice variant) and cytokeratin 5 remodelling program after influenza or bleomycin injury in mice. Activated cells proliferate and migrate widely to occupy heavily injured areas depleted of mature lineages, at which point they differentiate towards mature epithelium. Lineage tracing revealed scant contribution of pre-existing mature epithelial cells in such repair, whereas orthotopic transplantation of LNEPs, isolated by a definitive surface profile identified through single-cell sequencing, directly demonstrated the proliferative capacity and multipotency of this population. LNEPs require Notch signalling to activate the ΔNp63 and cytokeratin 5 program, and subsequent Notch blockade promotes an alveolar cell fate. Persistent Notch signalling after injury led to parenchymal 'micro-honeycombing' (alveolar cysts), indicative of failed regeneration. Lungs from patients with fibrosis show analogous honeycomb cysts with evidence of hyperactive Notch signalling. Our findings indicate that distinct stem/progenitor cell pools repopulate injured tissue depending on the extent of the injury, and the outcomes of regeneration or fibrosis may depend in part on the dynamics of LNEP Notch signalling.

Impact of Covid-19 on the therapeutic plasma exchange service within the South East Asian region: Consensus recommendations and global perspectives.

INTRODUCTION: Therapeutic plasma exchange (TPE) for neuroimmunological disorders has played an increasingly important role within the Southeast Asian (SEA) region. The South East Asian Therapeutic Plasma exchange Consortium (SEATPEC) was formed in 2018 to promote education and research on TPE within the region. The advent of the Covid-19 pandemic has produced challenges for the development and expansion of this service. METHODOLOGY: A qualitative and semi-quantitative questionnaire-based survey was conducted by SEATPEC member countries from January to June 2020 (Phase 1) and then from July 2020 to January 2021 in (Phase 2) to assess the impact of Covid-19 on regional TPE. OBJECTIVES: The study's main objectives were to explore the challenges experienced and adaptations/adjustments taken by SEATPEC countries in order to continue safe and efficient TPE during the Covid-19 pandemic. RESULTS: The pandemic was found to disrupt the delivery of TPE services in all SEATPEC countries. Contributing factors were multifactorial due to overstretched medical services, staff shortages, quarantines and redeployments, fear of acquiring Covid-19, movement restriction orders, and patient's psychological fear of attending hospitals/testing for Covid-19. All SEATPEC countries practiced careful stratification of cases for TPE (electives vs emergencies, Covid-19 vs non-Covid-19 cases). SEATPEC countries had to modify TPE treatment protocols to include careful preprocedure screening of patient's for Covid-19, use of personal protective equipment (PPE) and post-TPE sanitization of machines and TPE suites. CONCLUSION: Based on the responses of the survey, SEATPEC countries produced a consensus statement with five recommendations for safe and effective TPE within the region.

Individual, Family, and School Correlates across Patterns of High School Poly-substance Use.

Background: Recent popularity in e-cigarette use among high school students and the legalization of marijuana across many states resulted in new patterns of poly-substance use (PSU). Objective: The purpose of this study is to understand contemporary patterns of PSU and their associations with individual social-emotional characteristics (sensation seeking, perceived harm, life satisfaction) and social-contextual factors (parental involvement, school norms, academics, and behaviors). Methods: Latent class analysis (LCA) was used to identify patterns of PSU among 12th-grade students (n = 8417) from the 2016 Monitoring the Future project. Multinomial logistic regression was used to understand the relationship among individual characteristics, social-contextual factors, and patterns of PSU. Results: From the LCA, three patterns of PSU were identified: (1) low-use (72.2%); (2) pre-dominantly marijuana use with some co-occurring substance use (23.8%); and (3) high PSU (4.0%). Results indicate that students with pre-dominant marijuana use were differentiated from those with PSU by having higher perceived harm of electronic and regular cigarette, heavy alcohol use, and better academic grades. Furthermore, students with both polysubstance and pre-dominant marijuana use, when compared to those with low-use, had lower life satisfaction, higher sensation seeking, lower perceived harm of substance use, poorer grades, and more disciplinary problems. Conclusion/Importance: Findings draw attention to the importance of understanding levels of life satisfaction, sensation seeking, perceived harm, academic grades, and disciplinary problems as they pertain to contemporary patterns of PSU. Schools should consider a tailored and multi-tiered approach to addressing students' substance use.

Taming the Sentinels: Microbiome-Derived Metabolites and Polarization of T Cells.

A global increase in the prevalence of metabolic syndromes and digestive tract disorders, like food allergy or inflammatory bowel disease (IBD), has become a severe problem in the modern world. Recent decades have brought a growing body of evidence that links the gut microbiome's complexity with host physiology. Hence, understanding the mechanistic aspects underlying the synergy between the host and its associated gut microbiome are among the most crucial questions. The functionally diversified adaptive immune system plays a central role in maintaining gut and systemic immune homeostasis. The character of the reciprocal interactions between immune components and host-dwelling microbes or microbial consortia determines the outcome of the organisms' coexistence within the holobiont structure. It has become apparent that metabolic by-products of the microbiome constitute crucial multimodal transmitters within the host-microbiome interactome and, as such, contribute to immune homeostasis by fine-tuning of the adaptive arm of immune system. In this review, we will present recent insights and discoveries regarding the broad landscape of microbiome-derived metabolites, highlighting the role of these small compounds in the context of the balance between pro- and anti-inflammatory mechanisms orchestrated by the host T cell compartment.

Identifying and predicting criminal career profiles from adolescence to age 39.

Few longitudinal studies are capable of identifying criminal career profiles using both self-report and official court data beyond the 30s. The current study aims to identify criminal career profiles across three developmental periods using self-report data, validate these profiles with official court records and determine early childhood predictors. Data came from the Seattle Social Development Project (n = 808). Latent Class Analysis was used to examine criminal careers from self-reported data during adolescence (aged 14-18), early adulthood (aged 21-27) and middle adulthood (aged 30-39). Official court records were used to validate the classes. Childhood risk and promotive factors measured at ages 11-12 were used to predict classes. Findings revealed four career classes: non-offending (35.6%), adolescence-limited (33.2%), adult desister (18.3%) and life-course/persistent (12.9%). Official court records are consistent with the description of the classes. Early life school and family environments as well as having antisocial beliefs and friends differentiate membership across the classes. The results of this study, with a gender-balanced and racially diverse sample, bolster the current criminal career knowledge by examining multiple developmental periods into the 30s using both self-report and official court data.

Final year dental students' career plans, work patterns, work-life balance and domestic life in New Zealand and Australia.

INTRODUCTION: Having insight into final year dental students' career planning is vital in maintaining and enhancing the quality of dental education. The aim of this study was to investigate final year dental students' career plans, work patterns, work-life balance and domestic life, in New Zealand and Australia. METHODS: The design of the study was a two-centred cross-sectional study. RESULTS: A total of 148 students, including 95 females (64%) and 53 males (36%), completed the survey (response rate = 87%). The mean age of students across two Australasian universities was 23 ± 3 years. Findings from this study demonstrate that students prefer their first job is an urban, full-time and salary-based with a good mentor. However, when describing their long-term planning, work-life balance becomes more important. The growth in the number of female dentists will continue to shape the future patterns of our dental profession. CONCLUSION: The current study has highlighted several similarity and differences in career plans, work patterns, work-life balance and domestic life between two Australasian universities. The information might be useful for the policymakers involved in future workforce planning and infrastructure and for those involved in the delivery of dental education.

Viability Screen of LOPAC1280 Reveals Tyrosine Kinase Inhibitor Tyrphostin A9 as a Novel Partner Drug for Artesunate Combinations To Target the Plasmodium falciparum Ring Stage.

The emergence of artemisinin-resistant Plasmodium falciparum poses a major threat to current frontline artemisinin combination therapies. Artemisinin resistance is widely associated with mutations in the P. falciparum Kelch13 (PfKelch13) propeller region, leading to delayed parasite clearance and increased survival of early-ring-stage parasites. There is therefore a need to discover novel drugs that are effective against artemisinin-resistant P. falciparum In view of this, our study aimed to identify compounds from the Library of Pharmacologically Active Compounds1280 (LOPAC1280) that could increase the efficacy of artesunate and be used as a potential partner drug for treatment against artemisinin-resistant falciparum malaria. By using a modified ring-stage survival assay, we performed a high-throughput screening of the activities of the 1,280 compounds from the LOPAC library in combination with artesunate against the P. falciparum IPC 5202 field isolate harboring the R539T mutation in the PfKelch13 propeller region. The potencies of the hits against both the IPC 5202 and CamWT_C580Y field isolates were determined through dose-dependent isobologram analyses; CamWT_C580Y has the more prevalent C580Y mutation characteristic of strains with artemisinin resistance. We identified tyrphostin A9 to have synergistic and additive activity against both parasite strains when dosed in combination with artesunate. These findings provide promising novel artesunate combinations that can target the P. falciparum artemisinin-resistant ring stage and insights that may aid in obtaining a better understanding of the mechanism involved in artemisinin resistance.