High Juvenile Mortality Overwhelms Benefits of Mating Potential for Reproductive Fitness.

AbstractAn individual's access to mates (i.e., its "mating potential") can constrain its reproduction but may also influence its fitness through effects on offspring survival. For instance, mate proximity may correspond with relatedness and lead to inbreeding depression in offspring. While offspring production and survival might respond differently to mating potential, previous studies have not considered the simultaneous effects of mating potential on these fitness components. We investigated the relationship of mating potential with both production and survival of offspring in populations of a long-lived herbaceous perennial, Echinacea angustifolia. Across 7 years and 14 sites, we quantified the mating potential of maternal plants in 1,278 mating bouts and followed the offspring from these bouts over 8 years. We used aster models to evaluate the relationship of mating potential with the number of offspring that emerged and that were alive after 8 years. Seedling emergence increased with mating potential. Despite this, the number of offspring surviving after 8 years showed no relationship to mating potential. Our results support the broader conclusion that the effect of mating potential on fitness erodes over time because of demographic stochasticity at the maternal level.

Spatial and Temporal Resolution of Cyanobacterial Bloom Chemistry Reveals an Open-Ocean Trichodesmium thiebautii as a Talented Producer of Specialized Metabolites.

While the ecological role that Trichodesmium sp. play in nitrogen fixation has been widely studied, little information is available on potential specialized metabolites that are associated with blooms and standing stock Trichodesmium colonies. While a collection of biological material from a T. thiebautii bloom event from North Padre Island, Texas, in 2014 indicated that this species was a prolific producer of chlorinated specialized metabolites, additional spatial and temporal resolution was needed. We have completed these metabolite comparison studies, detailed in the current report, utilizing LC-MS/MS-based molecular networking to visualize and annotate the specialized metabolite composition of these Trichodesmium blooms and colonies in the Gulf of Mexico (GoM) and other waters. Our results showed that T. thiebautii blooms and colonies found in the GoM have a remarkably consistent specialized metabolome. Additionally, we isolated and characterized one new macrocyclic compound from T. thiebautii, trichothilone A (1), which was also detected in three independent cultures of T. erythraeum. Genome mining identified genes predicted to synthesize certain functional groups in the T. thiebautii metabolites. These results provoke intriguing questions of how these specialized metabolites affect Trichodesmium ecophysiology, symbioses with marine invertebrates, and niche development in the global oligotrophic ocean.

Juvenile survival increases with dispersal distance and varies across years: 15 years of evidence in a prairie perennial.

Juvenile survival is critical to population persistence and evolutionary change. However, the survival of juvenile plants from emergence to reproductive maturity is rarely quantified. This is especially true for long-lived perennials with extended pre-reproductive periods. Furthermore, studies rarely have the replication necessary to account for variation among populations and cohorts. We estimated juvenile survival and its relationship to population size, density of conspecifics, distance to the maternal plant, age, year, and cohort for Echinacea angustifolia, a long-lived herbaceous perennial. In 14 remnant prairie populations over seven sampling years, 2007-2013, we identified 886 seedlings. We then monitored these individuals annually until 2021 (8-15 years). Overall, juvenile mortality was very high; for almost all cohorts fewer than 10% of seedlings survived to age 8 or to year 2021. Only two of the seedlings reached reproductive maturity within the study period. Juvenile survival increased with distance from the maternal plant and varied more among the study years than it did by age or cohort. Juvenile survival did not vary with population size or local density of conspecific neighbors. Our results suggest that low juvenile survival could contribute to projected population declines.

Characteristics and co-morbidities associated with hospital discharges for opioid and methamphetamine co-use, United States 2016-2019.

Introduction: The US overdose crisis is increasingly characterized by opioid and methamphetamine co-use. Hospitalization is an important opportunity to engage patients in substance use treatment. Understanding characteristics of co-use-related hospital stays can inform the development of services to better support this growing patient population. Methods: We used 2016-2019 National Inpatient Sample data to conduct a cross sectional analysis of hospitalizations involving use of opioids, methamphetamine, or both. We used bivariate analysis to compare patient demographics. We then used multinomial logistic regressions to compare the proportion of hospital stays which indicated co-morbid diagnosis. To account for correlated data, we used generalized linear models to compare outcomes in hospital mortality, patient-directed discharge, and length of stay. Results: Co-use-related stays had a higher proportion of co-morbid mental health (60.7%; 95% CI: 59.9-61.4%) and infectious diseases (41.5%; 95% CI: 40.8-42.2%), than opioid- or methamphetamine-related stays. Co-use-related stays increased between 2016 and 2019 and were associated with a higher proportion of patient directed discharge (10.7%; 95% CI: 10.4-11.0%) and longer length of stay (6.3 days; 95% CI: 6.2-6.4 days) compared to opioid (8.1%; 95% CI: 7.9-8.3% and 5.8 days; 95% CI: 5.8-5.9 days) and methamphetamine-related stays (6.5%; 95% CI: 6.3-6.6% and 5.5 days; 95% CI: 5.4-5.5 days). Conclusion: Patients discharged with co-use differ from patients with opioid or methamphetamine use alone, representing a range of challenges and opportunities. In addition to offering treatment for both substance use disorders, hospital-based services that address co-occurring conditions may better support patients with co-use through targeted and tailored approaches.

Providers' Experiences and Perspectives in Treating Patients With Co-Occurring Opioid and Stimulant Use Disorders in the Hospital.

BACKGROUND: The overdose crisis is increasingly characterized by opioid and stimulant co-use. Despite effective pharmacologic treatment for both opioid use disorder (OUD) and contingency management for stimulant use disorders, most individuals with these co-occurring conditions are not engaged in treatment. Hospitalization is an important opportunity to engage patients and initiate treatment, however existing hospital addiction care is not tailored for patients with co-use and may not meet the needs of this population. METHODS: Semi-structured interviews were conducted with hospital providers about their experiences and perspectives treating patients with opioid and stimulant co-use. We used directed content analysis to identify common experiences and opportunities to improve hospital-based treatment for patients with co-use. RESULTS: From qualitative interviews with 20 providers, we identified 4 themes describing how co-use complicated hospital-based substance use treatment: (1) patients' unstable circumstances impacting the treatment plan, (2) co-occurring withdrawals are difficult to identify and treat, (3) providers holding more stigmatizing views of patients with co-use, and (4) stimulant use is often "ignored" in the treatment plans. Participants also described a range of potential opportunities to improve hospital-based treatment of co-use that fall into 3 categories: (1) provider practice changes, (2) healthcare system changes, and (3) development and validation of clinical tools and treatment approaches. CONCLUSIONS: We identified unique challenges providing hospital addiction medicine care to patients who use both opioids and stimulants. These findings inform the development, implementation, and testing of hospital-based interventions for patients with co-use.

Racial and Ethnic Differences in Heroin, Methamphetamine, and Cocaine Use, Treatment, and Mortality Trends in 3 National Data Sources-United States, 2010-2019.

BACKGROUND: As overdose deaths continue to rise, public health officials need comprehensive surveillance data to design effective prevention, harm reduction, and treatment strategies. Disparities across race and ethnicity groups, as well as trends in substance use, treatment, or overdose deaths, have been examined individually, but reports rarely compare findings across multiple substances or data sources. OBJECTIVE: To provide a broad assessment of the overdose crisis, we describe trends in substance use, treatment, and overdose mortality across racial and ethnic groups for multiple substances. RESEARCH DESIGN: We conducted a longitudinal, cross-sectional analysis comparing trends. SUBJECTS: We identified self-reported use from the National Survey on Drug Use and Health, substance use treatment admissions from the Treatment Episode Data Set-Admissions, and overdose deaths from the CDC's Multiple Cause of Death files. MEASURES: We measured rates of substance use, treatment, and deaths involving heroin, methamphetamine, and cocaine among United States adults from 2010 to 2019. RESULTS: Heroin, methamphetamine, and cocaine use increased, though not all changes were statistically significant. Treatment admissions indicating heroin and methamphetamine increased while admissions indicating cocaine decreased. Overdose deaths increased among all groups: methamphetamine (257%-1,115%), heroin (211%-577%), and cocaine (88%-259%). Changes in rates of use, treatment, and death for specific substances varied by racial and ethnic group. CONCLUSIONS: Substance use, treatment, and overdose mortality changed considerably, though not always equivalently. Identifying diverging trends in substance-related measures for specific substances and racial and ethnic groups can inform targeted investment in treatment to reduce disparities and respond to emerging changes in the overdose crisis.

Reaction hijacking inhibition of Plasmodium falciparum asparagine tRNA synthetase.

Malaria poses an enormous threat to human health. With ever increasing resistance to currently deployed drugs, breakthrough compounds with novel mechanisms of action are urgently needed. Here, we explore pyrimidine-based sulfonamides as a new low molecular weight inhibitor class with drug-like physical parameters and a synthetically accessible scaffold. We show that the exemplar, OSM-S-106, has potent activity against parasite cultures, low mammalian cell toxicity and low propensity for resistance development. In vitro evolution of resistance using a slow ramp-up approach pointed to the Plasmodium falciparum cytoplasmic asparaginyl-tRNA synthetase (PfAsnRS) as the target, consistent with our finding that OSM-S-106 inhibits protein translation and activates the amino acid starvation response. Targeted mass spectrometry confirms that OSM-S-106 is a pro-inhibitor and that inhibition of PfAsnRS occurs via enzyme-mediated production of an Asn-OSM-S-106 adduct. Human AsnRS is much less susceptible to this reaction hijacking mechanism. X-ray crystallographic studies of human AsnRS in complex with inhibitor adducts and docking of pro-inhibitors into a model of Asn-tRNA-bound PfAsnRS provide insights into the structure-activity relationship and the selectivity mechanism.

Single-cell multi-omic analysis of the vestibular schwannoma ecosystem uncovers a nerve injury-like state.

Vestibular schwannomas (VS) are benign tumors that lead to significant neurologic and otologic morbidity. How VS heterogeneity and the tumor microenvironment (TME) contribute to VS pathogenesis remains poorly understood. In this study, we perform scRNA-seq on 15 VS, with paired scATAC-seq (n = 6) and exome sequencing (n = 12). We identify diverse Schwann cell (SC), stromal, and immune populations in the VS TME and find that repair-like and MHC-II antigen-presenting SCs are associated with myeloid cell infiltrate, implicating a nerve injury-like process. Deconvolution analysis of RNA-expression data from 175 tumors reveals Injury-like tumors are associated with larger tumor size, and scATAC-seq identifies transcription factors associated with nerve repair SCs from Injury-like tumors. Ligand-receptor analysis and in vitro experiments suggest that Injury-like VS-SCs recruit myeloid cells via CSF1 signaling. Our study indicates that Injury-like SCs may cause tumor growth via myeloid cell recruitment and identifies molecular pathways that may be therapeutically targeted.

SH2 domain protein E and ABL signaling regulate blood vessel size.

Blood vessels in different vascular beds vary in size, which is essential for their function and fluid flow along the vascular network. Molecular mechanisms involved in the formation of a vascular lumen of appropriate size, or tubulogenesis, are still only partially understood. Src homology 2 domain containing E (She) protein was previously identified in a screen for proteins that interact with Abelson (Abl)-kinase. However, its biological role has remained unknown. Here we demonstrate that She and Abl signaling regulate vessel size in zebrafish embryos and human endothelial cell culture. Zebrafish she mutants displayed increased endothelial cell number and enlarged lumen size of the dorsal aorta (DA) and defects in blood flow, eventually leading to the DA collapse. Vascular endothelial specific overexpression of she resulted in a reduced diameter of the DA, which correlated with the reduced arterial cell number and lower endothelial cell proliferation. Chemical inhibition of Abl signaling in zebrafish embryos caused a similar reduction in the DA diameter and alleviated the she mutant phenotype, suggesting that She acts as a negative regulator of Abl signaling. Enlargement of the DA size in she mutants correlated with an increased endothelial expression of claudin 5a (cldn5a), which encodes a protein enriched in tight junctions. Inhibition of cldn5a expression partially rescued the enlarged DA in she mutants, suggesting that She regulates DA size, in part, by promoting cldn5a expression. SHE knockdown in human endothelial umbilical vein cells resulted in a similar increase in the diameter of vascular tubes, and also increased phosphorylation of a known ABL downstream effector CRKL. These results argue that SHE functions as an evolutionarily conserved inhibitor of ABL signaling and regulates vessel and lumen size during vascular tubulogenesis.

Hospital Addiction Medicine Consultation Service Orders and Outcomes by Patient Race and Ethnicity in an Urban, Safety-Net Hospital.

BACKGROUND: Hospital admissions involving substance use disorders are increasing and represent an opportunity to engage patients in substance use treatment. Addiction medicine consultation services improve access to medications for opioid use disorder (MOUD) and patient outcomes. However, as hospitals continue to adopt addiction medicine consultation services it is important to identify where disparities may emerge in the process of care. OBJECTIVE: To describe addiction medicine consultation service use by race and ethnicity as well as substance to identify opportunities to reduce substance use treatment disparities. DESIGN: Retrospective cohort study using 2016-2021 Electronic Health Record data from a large Midwest safety-net hospital. PARTICIPANTS: Hospitalized adults aged 18 or older, with one or more substance use disorders. MAIN MEASURES: Consultation orders placed, patient seen by consult provider, and receipt of MOUD by self-reported race. KEY RESULTS: Between 2016 and 2021, we identified 16,895 hospitalized patients with a substance use disorder. Consultation orders were placed for 6344 patients and 2789 were seen by the consult provider. Black patients were less likely (aOR = 0.58; 95% CI: 0.53-0.63) to have an addiction medicine consultation order placed and, among patients with a consultation order, were less likely (aOR = 0.74; 95% CI: 0.65-0.85) to be seen by the consult provider than White patients. Overall, Black patients with OUD were also less likely to receive MOUD in the hospital (aOR = 0.63; 95% CI: 0.50-0.79) compared to White patients. However, there were no differences in MOUD receipt among Black and White patients seen by the consult provider. CONCLUSIONS: Using Electronic Health Record data, we identified racial and ethnic disparities at multiple points in the inpatient addiction medicine consultation process. Addressing these disparities may support more equitable access to MOUD and other substance use treatment in the hospital setting.

Understanding Regional Patterns of Overdose Deaths Related to Opioids and Psychostimulants.

BACKGROUND: As overdose rates increase for multiple substances, policymakers need to identify geographic patterns of substance-specific deaths. In this study, we describe county-level opioid and psychostimulant overdose patterns and how they correlate with county-level social vulnerability measures. METHODS: A cross-sectional observational study, we used nationwide 2016-2018 restricted access Centers for Disease Prevention and Control county-level mortality files for 1,024 counties. We estimated quartiles of opioid and psychostimulant overdose mortality and provided estimates of their association with county-level Social Vulnerability Index (SVI) percentile. RESULTS: There was high opioid and psychostimulant overdose mortality in the Middle Atlantic, South Atlantic, East North Central, and Mountain regions. The Central US had the lowest opioid and psychostimulant overdose mortality rates. Counties with higher SVI scores (i.e. higher social vulnerability) were significantly more likely to experience high opioid and high psychostimulant overdose (high-high) mortality. A 10-percentile increase in SVI score was associated with a 3.1 percentage point increase in the likelihood of being a high-high county (p < 0.001) in unadjusted models and a 1.5 percentage point increase (p < 0.05) in models adjusting for region. CONCLUSION: Our results illustrated the heterogenous geographic distribution of the growing concurrent opioid and psychostimulant overdose crisis. The substantial regional variation we identified highlights the need for local data to guide policymaking and treatment planning. The association of opioid-psychostimulant overdose mortality with social vulnerability demonstrates the critical need in impacted counties for tailored treatment that addresses the complex medical and social needs of people who use both opioids and psychostimulants.

Leukemia-intrinsic determinants of CAR-T response revealed by iterative in vivo genome-wide CRISPR screening.

CAR-T therapy is a promising, novel treatment modality for B-cell malignancies and yet many patients relapse through a variety of means, including loss of CAR-T cells and antigen escape. To investigate leukemia-intrinsic CAR-T resistance mechanisms, we performed genome-wide CRISPR-Cas9 loss-of-function screens in an immunocompetent murine model of B-cell acute lymphoblastic leukemia (B-ALL) utilizing a modular guide RNA library. We identified IFNγR/JAK/STAT signaling and components of antigen processing and presentation pathway as key mediators of resistance to CAR-T therapy in vivo; intriguingly, loss of this pathway yielded the opposite effect in vitro (sensitized leukemia to CAR-T cells). Transcriptional characterization of this model demonstrated upregulation of these pathways in tumors relapsed after CAR-T treatment, and functional studies showed a surprising role for natural killer (NK) cells in engaging this resistance program. Finally, examination of data from B-ALL patients treated with CAR-T revealed an association between poor outcomes and increased expression of JAK/STAT and MHC-I in leukemia cells. Overall, our data identify an unexpected mechanism of resistance to CAR-T therapy in which tumor cell interaction with the in vivo tumor microenvironment, including NK cells, induces expression of an adaptive, therapy-induced, T-cell resistance program in tumor cells.

Taste loss as a distinct symptom of COVID-19: a systematic review and meta-analysis.

Chemosensory scientists have been skeptical that reports of COVID-19 taste loss are genuine, in part because before COVID-19 taste loss was rare and often confused with smell loss. Therefore, to establish the predicted prevalence rate of taste loss in COVID-19 patients, we conducted a systematic review and meta-analysis of 376 papers published in 2020-2021, with 235 meeting all inclusion criteria. Drawing on previous studies and guided by early meta-analyses, we explored how methodological differences (direct vs. self-report measures) may affect these estimates. We hypothesized that direct measures of taste are at least as sensitive as those obtained by self-report and that the preponderance of evidence confirms taste loss is a symptom of COVID-19. The meta-analysis showed that, among 138,015 COVID-19-positive patients, 36.62% reported taste dysfunction (95% confidence interval: 33.02%-40.39%), and the prevalence estimates were slightly but not significantly higher from studies using direct (n = 15) versus self-report (n = 220) methodologies (Q = 1.73, df = 1, P = 0.1889). Generally, males reported lower rates of taste loss than did females, and taste loss was highest among middle-aged adults. Thus, taste loss is likely a bona fide symptom of COVID-19, meriting further research into the most appropriate direct methods to measure it and its underlying mechanisms.

Structures of the interleukin 11 signalling complex reveal gp130 dynamics and the inhibitory mechanism of a cytokine variant.

Interleukin (IL-)11, an IL-6 family cytokine, has pivotal roles in autoimmune diseases, fibrotic complications, and solid cancers. Despite intense therapeutic targeting efforts, structural understanding of IL-11 signalling and mechanistic insights into current inhibitors are lacking. Here we present cryo-EM and crystal structures of the human IL-11 signalling complex, including the complex containing the complete extracellular domains of the shared IL-6 family ß-receptor, gp130. We show that complex formation requires conformational reorganisation of IL-11 and that the membrane-proximal domains of gp130 are dynamic. We demonstrate that the cytokine mutant, IL-11 Mutein, competitively inhibits signalling in human cell lines. Structural shifts in IL-11 Mutein underlie inhibition by altering cytokine binding interactions at all three receptor-engaging sites and abrogating the final gp130 binding step. Our results reveal the structural basis of IL-11 signalling, define the molecular mechanisms of an inhibitor, and advance understanding of gp130-containing receptor complexes, with potential applications in therapeutic development.

Minnesota Data Sharing May Be Model For Near-Real-Time Tracking Of Drug Overdose Hospital And ED Trends.

The drug overdose epidemic in the US necessitates detailed and timely data to inform public health responses. In this article we describe how an electronic health record (EHR) data-sharing collaboration across health systems in Minnesota that was developed in response to the COVID-19 pandemic was adapted to monitor trends in substance use-related hospital and emergency department (ED) visits. We found large increases in methamphetamine- and opioid-involved hospital and ED visits. Throughout the study period, Native American, Black, and multiple-race people experienced the highest rates of drug-involved hospital and ED visits. Monitoring drug-involved health care use through EHR data has the potential to help public health officials detect trends in near real time before mortality spikes and may also inform early intervention. The use of EHR data also allows for detailed monitoring of the impact of the drug overdose epidemic across racial and ethnic groups.

Efficacy of homoeopathic treatment: Systematic review of meta-analyses of randomised placebo-controlled homoeopathy trials for any indication.

BACKGROUND AND OBJECTIVE: Since 1997, several meta-analyses (MAs) of placebo-controlled randomised efficacy trials of homoeopathy for any indication (PRETHAIs) have been published with different methods, results and conclusions. To date, a formal assessment of these MAs has not been performed. The main objective of this systematic review of MAs of PRETHAIs was to evaluate the efficacy of homoeopathic treatment. METHODS: The inclusion criteria were as follows: MAs of PRETHAIs in humans; all ages, countries, settings, publication languages; and MAs published from 1 Jan. 1990 to 30 Apr. 2023. The exclusion criteria were as follows: systematic reviews without MAs; MAs restricted to age or gender groups, specific indications, or specific homoeopathic treatments; and MAs that did not assess efficacy. We searched 8 electronic databases up to 14 Dec. 2020, with an update search in 6 databases up to 30 April 2023. The primary outcome was the effect estimate for all included trials in each MA and after restricting the sample to trials with high methodological quality, according to predefined criteria. The risk of bias for each MA was assessed by the ROBIS (Risk Of Bias In Systematic reviews) tool. The quality of evidence was assessed by the GRADE framework. Statistical analyses were performed to determine the proportion of MAs showing a significant positive effect of homoeopathy vs. no significant difference. RESULTS: Six MAs were included, covering individualised homoeopathy (I-HOM, n = 2), nonindividualised homoeopathy (NI-HOM, n = 1) and all homoeopathy types (ALL-HOM = I-HOM + NI-HOM, n = 3). The MAs comprised between 16 and 110 trials, and the included trials were published from 1943-2014. The median trial sample size ranged from 45 to 97 patients. The risk of bias (low/unclear/high) was rated as low for three MAs and high for three MAs. Effect estimates for all trials in each MA showed a significant positive effect of homoeopathy compared to placebo (5 of 5 MAs, no data in 1 MA). Sensitivity analyses with sample restriction to high-quality trials were available from 4 MAs; the effect remained significant in 3 of the MAs (2 MAs assessed ALL-HOM, 1 MA assessed I-HOM) and was no longer significant in 1 MA (which assessed NI-HOM). DISCUSSION: The quality of evidence for positive effects of homoeopathy beyond placebo (high/moderate/low/very low) was high for I-HOM and moderate for ALL-HOM and NI-HOM. There was no support for the alternative hypothesis of no outcome difference between homoeopathy and placebo. The available MAs of PRETHAIs reveal significant positive effects of homoeopathy beyond placebo. This is in accordance with laboratory experiments showing partially replicable effects of homoeopathically potentised preparations in physico-chemical, in vitro, plant-based and animal-based test systems. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020209661. The protocol for this SR was finalised and submitted on 25 Nov. 2020 and registered on 26 Dec. 2020.

In-Situ-Grown Cu Dendrites Plasmonically Enhance Electrocatalytic Hydrogen Evolution on Facet-Engineered Cu2 O.

Herein, facet-engineered Cu2 O nanostructures are synthesized by wet chemical methods for electrocatalytic HER, and it is found that the octahedral Cu2 O nanostructures with exposed crystal planes of (111) (O-Cu2 O) has the best hydrogen evolution performance. Operando Raman spectroscopy and ex-situ characterization techniques showed that Cu2 O is reduced during HER, in which Cu dendrites are grown on the surface of the Cu2 O nanostructures, resulting in the better HER performance of O-Cu2 O after HER (O-Cu2 O-A) compared with that of the as-prepared O-Cu2 O. Under illumination, the onset potential of O-Cu2 O-A is ca. 52 mV positive than that of O-Cu2 O, which is induced by the plasmon-activated electrochemical system consisting of Cu2 O and the in-situ generated Cu dendrites. Incident photon-to-current efficiency (IPCE) measurements and the simulated UV-Vis spectrum demonstrate the hot electron injection (HEI) from Cu dendrites to Cu2 O. Ab initio nonadiabatic molecular dynamics (NAMD) simulations revealed the transfer of photogenerated electrons (27 fs) from Cu dendrites to Cu2 O nanostructures is faster than electron relaxation (170 fs), enhancing its surface plasmons activity, and the HEI of Cu dendrites increases the charge density of Cu2 O. These make the energy level of the catalyst be closer to that of H+ /H2 , evidenced by the plasmon-enhanced HER electrocatalytic activity.

Structure and regulation of full-length human leucine-rich repeat kinase 1.

The human leucine-rich repeat kinases (LRRKs), LRRK1 and LRRK2 are large and unusually complex multi-domain kinases, which regulate fundamental cellular processes and have been implicated in human disease. Structures of LRRK2 have recently been determined, but the structure and molecular mechanisms regulating the activity of the LRRK1 as well as differences in the regulation of LRRK1 and LRRK2 remain unclear. Here, we report a cryo-EM structure of the LRRK1 monomer and a lower-resolution cryo-EM map of the LRRK1 dimer. The monomer structure, in which the kinase is in an inactive conformation, reveals key interdomain interfaces that control kinase activity as we validate experimentally. Both the LRRK1 monomer and dimer are structurally distinct compared to LRRK2. Overall, our results provide structural insights into the activation of the human LRRKs, which advance our understanding of their physiological and pathological roles.

Reaction hijacking inhibition of Plasmodium falciparum asparagine tRNA synthetase.

Malaria poses an enormous threat to human health. With ever increasing resistance to currently deployed drugs, breakthrough compounds with novel mechanisms of action are urgently needed. Here, we explore pyrimidine-based sulfonamides as a new low molecular weight inhibitor class with drug-like physical parameters and a synthetically accessible scaffold. We show that the exemplar, OSM-S-106, has potent activity against parasite cultures, low mammalian cell toxicity and low propensity for resistance development. In vitro evolution of resistance using a slow ramp-up approach pointed to the Plasmodium falciparum cytoplasmic asparaginyl tRNA synthetase (PfAsnRS) as the target, consistent with our finding that OSM-S-106 inhibits protein translation and activates the amino acid starvation response. Targeted mass spectrometry confirms that OSM-S-106 is a pro-inhibitor and that inhibition of PfAsnRS occurs via enzyme-mediated production of an Asn-OSM-S-106 adduct. Human AsnRS is much less susceptible to this reaction hijacking mechanism. X-ray crystallographic studies of human AsnRS in complex with inhibitor adducts and docking of pro-inhibitors into a model of Asn-tRNA-bound PfAsnRS provide insights into the structure activity relationship and the selectivity mechanism.