👤 Mark R Wilkinson

The utility of coronary artery calcium (CAC) scoring in individuals with elevated lipoprotein(a) [Lp(a)] for atherosclerotic cardiovascular disease (ASCVD) risk assessment is currently unclear given the propensity of Lp(a) toward noncalcified plaque. The authors aimed to evaluate the interaction between elevated Lp(a) (>50 mg/dL) and CAC score, and the association of Lp(a) with ASCVD risk across strata of CAC. A pooled cohort of participants without known ASCVD from 4 U.S.-based prospective cohort studies with baseline Lp(a) and CAC measurements was used. The association between elevated Lp(a) across CAC strata and incident ASCVD (myocardial infarction, stroke, coronary revascularization) was evaluated in multivariable Cox regression models. The study included 11,319 participants (mean age 56 years, 54% women) with 1,569 incident ASCVD events over 14.8 year mean follow-up. Lp(a) >50 mg/dL (HR: 1.24; 95% CI: 1.09-1.41) and CAC >0 (HR: 2.44; 95% CI: 2.14-2.77) were independently associated with ASCVD risk (P interaction = 0.80). Among individuals with CAC = 0, ASCVD incidence rates were low overall, but higher with Lp(a) >50 mg/dL vs ≤50 mg/dL (4.9 vs 3.8/1,000 person-years, HR: 1.28; 95% CI: 1.01-1.60). Among those with CAC >0, increased risk was again noted with elevated Lp(a) (21.2 vs 18.2/1,000 person-years, HR: 3.03; 95% CI: 2.52-3.64). Similar results were observed when examining further CAC strata with the greatest risk noted with both CAC ≥300 and Lp(a) >50 mg/dL (HR: 6.12; 95% CI: 4.80-7.81). Consistent results were noted by age and sex with greater absolute risk in general among individuals >50 years of age and men. Elevated Lp(a) is associated with higher relative risk across CAC strata, including CAC of 0. Among individuals with CAC of 0, absolute event rates remain low even when Lp(a) is elevated. CAC scoring remains a powerful tool for risk assessment among individuals with elevated Lp(a). Show less

Lipoprotein(a) [Lp(a)] is a genetically determined risk factor for myocardial infarction and stroke. Elevated Lp(a) >50 mg/dL (>125 nmol/L) is common and present in about 1 in 5 individuals. Although Lp(a) may be a cause of young ischemic stroke (age ≤60), limited data on national testing trends in this population are available, testing in the general population remains low overall, and different organizations have varying guidelines for testing. By determining the degree to which this population is tested, information on national testing trends of Lp(a) in young ischemic stroke patients may influence future guideline recommendations to increase Lp(a) testing. This study aims to use a large, real-world dataset to assess trends of Lp(a) testing in young ischemic stroke patients in the United States from 2015-2024. We performed a retrospective analysis of Lp(a) testing in young ischemic stroke patients across the United States from January 1, 2015 to December 31, 2024 using Epic Cosmos, a nationwide, de-identified electronic health record (EHR) dataset comprising over 300 million patient records from over 1,715 hospitals and 41,000 clinics, including from all 50 states, Washington D.C., Lebanon, and Saudi Arabia. The current count values for patients, hospitals, and clinics are available on the Epic Cosmos website. Although the Epic Cosmos data dictionary includes Lebanon and Saudi Arabia as standardized site locations, no patients from these countries were present in our analytic cohort; thus, all analyses were restricted to individuals within the United States. We evaluated the number of young ischemic stroke patients, defined as age ≤60 with history of an ischemic cerebrovascular accident (CVA), who had ever undergone Lp(a) testing, the testing rate per annual young ischemic stroke patients, geographical variation, and percentages of patients tested stratified by age, sex, ethnicity, race, and diagnosis of coronary artery disease (CAD). Testing rates were calculated as the number of distinct patients tested per year and as the testing rate per annual patient population. For each stratum we calculated the proportion tested with Wilson 95 % confidence intervals and assessed between-group differences using chi square or Fisher exact tests as appropriate. Annual trends in the testing proportion were modeled using a binomial generalized linear model with a logit link, treating the annual number tested as the numerator and the annual young ischemic stroke population as the denominator, and we report the odds ratio per calendar year with robust standard errors. Geographical variation was visualized using a heat map of testing by state. All analyses were descriptive and intended to characterize population-level patterns of ischemic stroke within the Cosmos network rather than infer causal associations. Given the exploratory design, no additional model-based adjustment for confounding was performed. All data are de-identified in compliance with HIPAA standards and governed under Epic's "Rules of the Road" for institutional data use. From 2015 to 2024, out of a total of 188,305 distinct young ischemic stroke patients, 9,226 (4.9 %) underwent Lp(a) testing. Additionally, the annual number of tested patients increased significantly from 179 in 2015 to 1,992 in 2024 (p<0.001), and the annual percentage of patients undergoing Lp(a) testing increased from 4.3 % in 2015 to 9.3 % in 2024. The states with the largest number of tested patients were Ohio (10.4 %), Texas (7.4 %), and Pennsylvania (5.5 %). The rates of testing were significantly different between sexes, with a larger percentage of young women with ischemic strokes tested compared to young men. Analyzing patients with reported racial data, patients who identified as Black or African American underwent testing for Lp(a) at the highest rate, compared with patients who identified as Asian, "None of the above", White, or Other Race. Among patients undergoing testing with reported ethnic identity, a higher percentage of patients who identified as Hispanic or Latino were tested compared to those who identified as non-Hispanic. Stratifying the total tested patients by age, adults between the ages of 50-60 years made up the largest percentage of patients (4,460; 48.3 %); however, the highest rate of testing occurred in patients aged 5-18. In addition, a higher rate of the young ischemic stroke patients who had ever had a diagnosis of CAD underwent testing compared to patients without CAD. Lp(a) testing among young ischemic stroke patients has increased significantly over the past decade, likely reflecting growing clinical recognition of its causal role in atherosclerotic disease. The rise parallels key updates in lipid management and stroke prevention guidelines, including the 2019 European Society of Cardiology and 2024 National Lipid Association recommendations advocating at least once-in-a-lifetime Lp(a) measurement. Increasing assay availability and heightened awareness of the causal relationship of Lp(a) with atherosclerotic disease may also have contributed to the observed upward trend. Despite this, only about one in twenty young ischemic stroke patients had ever been tested, underscoring a substantial implementation gap between evidence and clinical practice. Show less

With no currently available targeted therapies for lipoprotein(a) [Lp(a)] lowering, proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) may be an option for management of increased cardiovascular risk in individuals with elevated Lp(a). However, Lp(a) lowering with PCSK9i is variable. We aimed to evaluate the real-world change in Lp(a) and predictors of response. Using data from the University of California Health Data Warehouse, we conducted a multi-center retrospective study among adults prescribed PCSK9i therapy with available Lp(a) measurement before and after prescription. We evaluated change in Lp(a) compared to baseline and evaluated potential predictors of Lp(a) reduction using multivariable linear regression, including among patients with multiple serial Lp(a) measurements. Among 453 included individuals, PCSK9i use was associated with a median 17.3 [IQR 35.3, 0.0]% and 11.3 [31.7, 0.0] mg/dL reduction in Lp(a) overall. Among those with Lp(a) >50 mg/dL, a 17.7 [33.6, 0.0]% and 19.2 [42.0, 0.0] mg/dL reduction was observed. Higher baseline Lp(a) level (β -0.31, p<0.001) was a significant predictor of greater Lp(a) reduction, while female sex was associated with less reduction (β 9.28, p=0.02). Results were consistent across Lp(a) assay types and by PCSK9i type and sustained in those with serial Lp(a) measurements (n=274). In contrast, in a control group of 6750 individuals, a median change of 0.00 [-2.00, 3.00] mg/dL in Lp(a) was noted in serial measurements. PCSK9i are associated with modest Lp(a) lowering of approximately 17% in real-world clinical practice, with a consistent percent reduction by baseline Lp(a) level, PCSK9i type and Lp(a) assay type. Predictors of Lp(a) reduction include baseline Lp(a) level and sex without significant variation by age, race/ethnicity or other evaluated comorbidities. Show less

Snakebites affect about 1.8 million people annually. The current standard of care involves antibody-based antivenoms, which can be difficult to access and are generally not effective against local tissue injury, the primary cause of morbidity. Here, we used a pooled whole-genome CRISPR knockout screen to define human genes that, when targeted, modify cell responses to spitting cobra venoms. A large portion of modifying genes that conferred resistance to venom cytotoxicity was found to control proteoglycan biosynthesis, including Show less

MLLT10 fusion is a rare but recurrent genetic driver in acute leukemias. To better understand the genomic landscape of PICALM::MLLT10 (PM) positive acute leukemia, we performed genomic profiling and gene expression profiling in twenty PM-positive patients, including AML (n = 10), T-ALL/LLy (n = 8), Mixed-phenotype acute leukemia (MPAL), T/B (n = 1) and acute undifferentiated leukemia (AUL) (n = 1). Besides confirming the known activation of HOXA, differential gene expression analysis compared to hematopoietic stem cells demonstrated the enrichment of genes associated with cell proliferation-related pathways and relatively high expression of XPO1 in PM-AML and PM-T-ALL/LLy. Our study also suggested PHF6 disruption as a key cooperating event in PICALM::MLLT10-positive leukemias. In addition, we demonstrated differences in gene expression profiles as well as remarkably different spectra of co-occurring mutations between PM-AML and PM-T-ALL/LLy. Alterations affecting TP53 and NF1, hallmarks of PM-AML, are strongly associated with disease progression and relapse, whereas EZH2 alterations are highly enriched in PM-T-ALL/LLy. This comprehensive genomic and transcriptomic profiling provides insights into the pathogenesis and development of PICALM::MLLT10 positive acute leukemia. Show less

Men taking antioxidant vitamin E supplements have increased prostate cancer (PC) risk. However, whether pro-oxidants protect from PC remained unclear. In this work, we show that a pro-oxidant vitamin K precursor [menadione sodium bisulfite (MSB)] suppresses PC progression in mice, killing cells through an oxidative cell death: MSB antagonizes the essential class III phosphatidylinositol (PI) 3-kinase VPS34-the regulator of endosome identity and sorting-through oxidation of key cysteines, pointing to a redox checkpoint in sorting. Testing MSB in a myotubular myopathy model that is driven by loss of Show less

Variations in the Dlg2 gene have been linked to increased risk for psychiatric disorders, including schizophrenia, autism spectrum disorders, intellectual disability, bipolar disorder, attention deficit hyperactivity disorder, and pubertal disorders. Recent studies have reported disrupted brain circuit function and behaviour in models of Dlg2 knockout and haploinsufficiency. Specifically, deficits in hippocampal synaptic plasticity were found in heterozygous Dlg2+/- rats suggesting impacts on hippocampal dependent learning and cognitive flexibility. Here, we tested these predicted effects with a behavioural characterisation of the heterozygous Dlg2+/- rat model. Dlg2+/- rats exhibited a specific, mild impairment in reversal learning in a substrate deterministic bowl-digging reversal learning task. The performance of Dlg2+/- rats in other bowl digging task, visual discrimination and reversal, novel object preference, novel location preference, spontaneous alternation, modified progressive ratio, and novelty-suppressed feeding test were not impaired. These findings suggest that despite altered brain circuit function, behaviour across different domains is relatively intact in Dlg2+/- rats, with the deficits being specific to only one test of cognitive flexibility. The specific behavioural phenotype seen in this Dlg2+/- model may capture features of the clinical presentation associated with variation in the Dlg2 gene. Show less

Mycobacterium tuberculosis (M. tuberculosis) is an intracellular pathogen that primarily infects macrophages. Despite a robust anti-mycobacterial response, many times macrophages are unable to control M. tuberculosis. The purpose of this study was to investigate the mechanism by which the immunoregulatory cytokine IL-27 inhibits the anti-mycobacterial activity of primary human macrophages. We found concerted production of IL-27 and anti-mycobacterial cytokines by M. tuberculosis-infected macrophages in a toll-like receptor (TLR) dependent manner. Notably, IL-27 suppressed the production of anti-mycobacterial cytokines TNFα, IL-6, IL-1β, and IL-15 by M. tuberculosis-infected macrophages. IL-27 limits the anti-mycobacterial activity of macrophages by reducing Cyp27B, cathelicidin (LL-37), LC3B lipidation, and increasing IL-10 production. Furthermore, neutralizing both IL-27 and IL-10 increased the expression of proteins involved in LC3-associated phagocytosis (LAP) pathway for bacterial clearance, namely vacuolar-ATPase, NOX2, and RUN-domain containing protein RUBCN. These results implicate IL-27 is a prominent cytokine that impedes M. tuberculosis clearance. Show less

Mutations affecting DLG2 are emerging as a genetic risk factor associated with neurodevelopmental psychiatric disorders including schizophrenia, autism spectrum disorder, and bipolar disorder. Discs large homolog 2 (DLG2) is a member of the membrane-associated guanylate kinase protein superfamily of scaffold proteins, a component of the post-synaptic density in excitatory neurons and regulator of synaptic function and plasticity. It remains an important question whether and how haploinsuffiency of DLG2 contributes to impairments in basic behavioural and cognitive functions that may underlie symptomatic domains in patients that cross diagnostic boundaries. Using a heterozygous Dlg2 mouse model we examined the impact of reduced Dlg2 expression on functions commonly impaired in neurodevelopmental psychiatric disorders including motor co-ordination and learning, pre-pulse inhibition and habituation to novel stimuli. The heterozygous Dlg2 mice exhibited behavioural impairments in long-term motor learning and long-term habituation to a novel context, but not motor co-ordination, initial responses to a novel context, PPI of acoustic startle or anxiety. We additionally showed evidence for the reduced regulation of the synaptic plasticity-associated protein cFos in the motor cortex during motor learning. The sensitivity of selective behavioural and cognitive functions, particularly those dependent on synaptic plasticity, to reduced expression of DLG2 give further credence for DLG2 playing a critical role in specific brain functions but also a mechanistic understanding of symptom expression shared across psychiatric disorders. Show less

Copy number variants indicating loss of function in the DLG2 gene have been associated with markedly increased risk for schizophrenia, autism spectrum disorder, and intellectual disability. DLG2 encodes the postsynaptic scaffolding protein DLG2 (PSD93) that interacts with NMDA receptors, potassium channels, and cytoskeletal regulators but the net impact of these interactions on synaptic plasticity, likely underpinning cognitive impairments associated with these conditions, remains unclear. Here, hippocampal CA1 neuronal excitability and synaptic function were investigated in a novel clinically relevant heterozygous Dlg2+/- rat model using ex vivo patch-clamp electrophysiology, pharmacology, and computational modelling. Dlg2+/- rats had reduced supra-linear dendritic integration of synaptic inputs resulting in impaired associative long-term potentiation. This impairment was not caused by a change in synaptic input since NMDA receptor-mediated synaptic currents were, conversely, increased and AMPA receptor-mediated currents were unaffected. Instead, the impairment in associative long-term potentiation resulted from an increase in potassium channel function leading to a decrease in input resistance, which reduced supra-linear dendritic integration. Enhancement of dendritic excitability by blockade of potassium channels or activation of muscarinic M1 receptors with selective allosteric agonist 77-LH-28-1 reduced the threshold for dendritic integration and 77-LH-28-1 rescued the associative long-term potentiation impairment in the Dlg2+/- rats. These findings demonstrate a biological phenotype that can be reversed by compound classes used clinically, such as muscarinic M1 receptor agonists, and is therefore a potential target for therapeutic intervention. Show less

Genetic studies implicate disruption to the DLG2 gene in copy number variants as increasing risk for schizophrenia, autism spectrum disorders and intellectual disability. To investigate psychiatric endophenotypes associated with DLG2 haploinsufficiency (and concomitant PSD-93 protein reduction) a novel clinically relevant Dlg2 Show less

Reading Disability (RD) is often characterized by difficulties in the phonology of the language. While the molecular mechanisms underlying it are largely undetermined, loci are being revealed by genome-wide association studies (GWAS). In a previous GWAS for word reading (Price, 2020), we observed that top single-nucleotide polymorphisms (SNPs) were located near to or in genes involved in neuronal migration/axon guidance (NM/AG) or loci implicated in autism spectrum disorder (ASD). A prominent theory of RD etiology posits that it involves disturbed neuronal migration, while potential links between RD-ASD have not been extensively investigated. To improve power to identify associated loci, we up-weighted variants involved in NM/AG or ASD, separately, and performed a new Hypothesis-Driven (HD)-GWAS. The approach was applied to a Toronto RD sample and a meta-analysis of the GenLang Consortium. For the Toronto sample (n = 624), no SNPs reached significance; however, by gene-set analysis, the joint contribution of ASD-related genes passed the threshold (p~1.45 × 10 Show less

AF10, a DOT1L cofactor, is required for H3K79 methylation and cooperates with DOT1L in leukemogenesis. However, the molecular mechanism by which AF10 regulates DOT1L-mediated H3K79 methylation is not clear. Here we report that AF10 contains a "reader" domain that couples unmodified H3K27 recognition to H3K79 methylation. An AF10 region consisting of a PHD finger-Zn knuckle-PHD finger (PZP) folds into a single module that recognizes amino acids 22-27 of H3, and this interaction is abrogated by H3K27 modification. Structural studies reveal that H3 binding triggers rearrangement of the PZP module to form an H3(22-27)-accommodating channel and that the unmodified H3K27 side chain is encased in a compact hydrogen-bond acceptor-lined cage. In cells, PZP recognition of H3 is required for H3K79 dimethylation, expression of DOT1L-target genes, and proliferation of DOT1L-addicted leukemic cells. Together, our results uncover a pivotal role for H3K27-via readout by the AF10 PZP domain-in regulating the cancer-associated enzyme DOT1L. Show less

Defects in centrosome and cilium function are associated with phenotypically related syndromes called ciliopathies. Centriolar satellites are centrosome-associated structures, defined by the protein PCM1, that are implicated in centrosomal protein trafficking. We identify Cep72 as a PCM1-interacting protein required for recruitment of the ciliopathy-associated protein Cep290 to centriolar satellites. Loss of centriolar satellites by depletion of PCM1 causes relocalization of Cep72 and Cep290 from satellites to the centrosome, suggesting that their association with centriolar satellites normally restricts their centrosomal localization. We identify interactions between PCM1, Cep72, and Cep290 and find that disruption of centriolar satellites by overexpression of Cep72 results in specific aggregation of these proteins and the BBSome component BBS4. During ciliogenesis, BBS4 relocalizes from centriolar satellites to the primary cilium. This relocalization occurs normally in the absence of centriolar satellites (PCM1 depletion) but is impaired by depletion of Cep290 or Cep72, resulting in defective ciliary recruitment of the BBSome subunit BBS8. We propose that Cep290 and Cep72 in centriolar satellites regulate the ciliary localization of BBS4, which in turn affects assembly and recruitment of the BBSome. Finally, we show that loss of centriolar satellites in zebrafish leads to phenotypes consistent with cilium dysfunction and analogous to those observed in human ciliopathies. Show less

The mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase/AKT signaling pathways interact at multiple nodes in cancer, including at mTOR complexes, suggesting an increased likelihood of redundancy and innate resistance to any therapeutic effects of single pathway inhibition. In this study, we investigated the therapeutic effects of combining the MAPK extracellular signal-regulated kinase (MEK)1/2 inhibitor selumetinib (AZD6244) with the dual mTORC1 and mTORC2 inhibitor (AZD8055). Concurrent dosing in nude mouse xenograft models of human lung adenocarcinoma (non-small cell lung cancers) and colorectal carcinoma was well tolerated and produced increased antitumor efficacy relative to the respective monotherapies. Pharmacodynamic analysis documented reciprocal pathway inhibition associated with increased apoptosis and Bim expression in tumor tissue from the combination group, where key genes such as DUSP6 that are under MEK functional control were also modulated. Our work offers a strong rationale to combine selumetinib and AZD8055 in clinical trials as an attractive therapeutic strategy. Show less

Vasculogenesis, the de novo formation of blood vessels from precursor cells is critical for a developing embryo. However, the signals and events that dictate the formation of primary axial vessels remain poorly understood. In this study, we use ets-related protein-1 (etsrp), which is essential for vascular development, to analyze the early stages of vasculogenesis in zebrafish. We found etsrp(+) cells of the head, trunk and tail follow distinct developmental sequences. Using a combination of genetic, molecular and chemical approaches, we demonstrate that fli(+)etsrp(+) hemato-vascular progenitors (FEVPs) are proliferating at the lateral plate mesoderm (LPM). The Shh-VEGF-Notch-Hey2 signaling pathway controls the proliferation process, and experimental modulation of single components of this pathway alters etsrp(+) cell numbers at the LPM. This study for the first time defines factors controlling proliferation, and cell numbers of pre-migratory FEVPs in zebrafish. Show less

The Structural Proteomics In Europe (SPINE) programme is aimed at the development and implementation of high-throughput technologies for the efficient structure determination of proteins of biomedical importance, such as those of bacterial and viral pathogens linked to human health. Despite the challenging nature of some of these targets, 175 novel pathogen protein structures (approximately 220 including complexes) have been determined to date. Here the impact of several technologies on the structural determination of proteins from human pathogens is illustrated with selected examples, including the parallel expression of multiple constructs, the use of standardized refolding protocols and optimized crystallization screens. Show less