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Neurodegenerative disease in C9orf72 repeat expansion carriers: population risk and effect of UNC13A.
The C9orf72 hexanucleotide repeat expansion (HRE) is the most common monogenetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Neurodegenerative disease incidence in C9orf72 HRE carriers has been studied using cohorts from disease-affected families or by extrapolating from population disease incidence, potentially introducing bias. Age-specific cumulative incidence of ALS and dementia was estimated using Kaplan-Meier and competing risk models in C9orf72 HRE carriers compared to matched controls in UK Biobank. Risk modification by UNC13A genotype was examined. Of 490,331 individuals with valid genetic data, 701 had >100 repeats in C9orf72 (median age 55 [IQR 48-62], follow-up 13.4 years [12.3-14.1]). The cumulative incidence of ALS or dementia was 66% [95% CI 57-73%] by age 80 in C9orf72 HRE carriers versus 5.8% [4.5-7.0%] in controls, or 58% [50-64%] versus 5.1% [4.1-6.4%] accounting for the competing risk of other-cause mortality. Forty-one percent of dementia incidence accrued between age 75-80. C-allele homozygosity at rs12608932 in UNC13A increased ALS or dementia risk in C9orf72 HRE carriers (hazard ratio 1.81 [1.18 - 2.78]). C9orf72 HRE disease was incompletely penetrant in this population-based cohort, with risk modified by UNC13A genotype. This has implications for counselling at-risk individuals and modelling expected phenoconversion for prevention trials.
Erythropoiesis in the human
Erythropoiesis is the production of haemoglobin-containing red blood cells for oxygen delivery to the tissues. Approximately 1-2 Ã- 1012red cells are produced each day, and this remarkable productivity under stable conditions is also complemented by the capacity for rapid and substantial expansion when required. This chapter describes the developmental origins of primitive and definitive erythropoiesis in the yolk sac, the fetal liver and the bone marrow. Our current understanding of the mechanisms of erythroid lineage specification from multipotent haemopoietic stem cells remains incomplete, but key erythroid-specific transcription factors are known to be critical in directing erythroid-specific transcription. Characteristic changes in morphology, gene expression and cell surface markers allow the identification of erythroid cells at different stages of their differentiation and maturation. At a system level, the hormone erythropoietin is the principal regulator of erythroid activity. Following upregulation of its transcription by Hypoxia-Inducible Factor, erythropoietin directs an expansion of the pool of erythroid precursors and accelerated red cell maturation. This, together with coordinated iron absorption and delivery, provides an appropriate response to hypoxia caused by reduced numbers of circulating red blood cells associated with a very wide spectrum of causes.
Widespread Changes in the Immunoreactivity of Bioactive Peptide T14 After Manipulating the Activity of Cortical Projection Neurons
Previous studies have suggested that T14, a 14-amino-acid peptide derived from acetylcholinesterase (AChE), functions as an activity-dependent signalling molecule with key roles in brain development, and its dysregulation has been linked to neurodegeneration in Alzheimer’s disease. In this study, we examined the distribution of T14 under normal developmental conditions in the mouse forebrain, motor cortex (M1), striatum (STR), and substantia nigra (SN). T14 immunoreactivity declined from E16 to E17 and further decreased by P0, then peaked at P7 during early postnatal development before declining again by adulthood at P70. Lower T14 immunoreactivity in samples processed without Triton indicated that T14 is primarily localised intracellularly. To explore the relationship between T14 expression and neuronal activity, we used mouse models with chronic silencing (Rbp4Cre-Snap25), acute silencing (Rbp4Cre-hM4Di), and acute activation (Rbp4Cre-hM3D1). Chronic silencing altered the location and size of intracellular T14-immunoreactive particles in adult brains, while acute silencing had no observable effect. In contrast, acute activation increased T14+ density in the STR, modified T14 puncta size near Rbp4Cre cell bodies in M1 layer 5 and their projections to the STR, and enhanced co-localisation of T14 with presynaptic terminals in the SN.
Ketosis regulates K+ ion channels, strengthening brain-wide signaling disrupted by age.
Aging is associated with impaired signaling between brain regions when measured using resting-state fMRI. This age-related destabilization and desynchronization of brain networks reverses itself when the brain switches from metabolizing glucose to ketones. Here, we probe the mechanistic basis for these effects. First, we confirmed their robustness across measurement modalities using two datasets acquired from resting-state EEG (Lifespan: standard diet, 20-80 years, N = 201; Metabolic: individually weight-dosed and calorically-matched glucose and ketone ester challenge, μ a g e = 26.9 ± 11.2 years , N = 36). Then, using a multiscale conductance-based neural mass model, we identified the unique set of mechanistic parameters consistent with our clinical data. Together, our results implicate potassium (K+) gradient dysregulation as a mechanism for age-related neural desynchronization and its reversal with ketosis, the latter finding of which is consistent with direct measurement of ion channels. As such, the approach facilitates the connection between macroscopic brain activity and cellular-level mechanisms.
Gamma activation spread reflects disease activity in amyotrophic lateral sclerosis.
OBJECTIVE: A non-invasive measure of cerebral motor system dysfunction would be valuable as a biomarker in amyotrophic lateral sclerosis (ALS). Task-based magnetoencephalography (tMEG) measures the magnetic fields generated by cortical neuronal oscillatory activity during task performance. Gamma activations are periods of high-power and high-frequency cortical oscillations integral to motor control. METHODS: tMEG was undertaken during 60 bilateral isometric hand grip exercises in ALS (n = 42) and compared with healthy controls (HC, n = 33). Gamma activation spread (GAS) was estimated by calculating the number of activated regions during each 100 ms time-bin and compared statistically between groups. Gamma activation patterns were visualised by plotting each participant's brain activity separately as a 2-dimensional video. RESULTS: There was no difference in grip strength between groups. GAS was greatly increased in the ALS group compared to HC (p
Tumor-Infiltrating Clonal Hematopoiesis.
BACKGROUND: Clonal hematopoiesis of indeterminate potential (CHIP) is an age-related condition associated with increased mortality among patients with cancer. CHIP mutations with high variant-allele frequencies can be detected in tumors, a phenomenon we term tumor-infiltrating clonal hematopoiesis (TI-CH). The frequency of TI-CH and its effect on tumor evolution are unclear. METHODS: We characterized CHIP and TI-CH in 421 patients with early-stage non-small-cell lung cancer (NSCLC) from the TRACERx study and in 49,351 patients from the MSK-IMPACT pan-cancer cohort. We studied the association of TI-CH with survival and disease recurrence and evaluated the functional effect of TET2-mutant CHIP on the biologic features of lung tumors. RESULTS: Among patients with NSCLC, 42% of those with CHIP had TI-CH. TI-CH independently predicted an increased risk of death or recurrence, with an adjusted hazard ratio of 1.80 (95% confidence interval [CI], 1.23 to 2.63) as compared with the absence of CHIP and an adjusted hazard ratio of 1.62 (95% CI, 1.02 to 2.56) as compared with CHIP in the absence of TI-CH. Among patients with solid tumors, 26% of those with CHIP had TI-CH. TI-CH conferred a risk of death from any cause that was 1.17 times (95% CI, 1.06 to 1.29) as high as the risk with CHIP in the absence of TI-CH. TET2 mutations were the strongest genetic predictor of TI-CH; such mutations enhanced monocyte migration to lung tumor cells, fueled a myeloid-rich tumor microenvironment in mice, and resulted in the promotion of tumor organoid growth. CONCLUSIONS: TI-CH increased the risk of disease recurrence or death among patients with NSCLC and the risk of death from any cause among patients with solid tumors. TI-CH remodeled the tumor immune microenvironment and accelerated tumor organoid growth, findings that support a role for an aging-related hematologic clonal proliferation in cancer evolution. (Funded by the Royal Society and others.).
Fedratinib combined with ropeginterferon alfa-2b in patients with myelofibrosis (FEDORA): study protocol for a multicentre, open-label, Bayesian phase II trial.
BACKGROUND: Myelofibrosis (MF) is a clonal haematopoietic disease, with median overall survival for patients with primary MF only 6.5 years. The most frequent gene mutation found in patients is JAK2V617F, causing constitutive activation of the kinase and activation of downstream signalling. Fedratinib is an oral selective JAK2 inhibitor. It has shown activity in MF and is well-tolerated, but combination with other therapies is likely needed to achieve clonal remission. Combining a JAK2 inhibitor with an interferon may be synergistic, as haematopoietic cells are activated from quiescence (a typical kinase resistance mechanism) rendering them more sensitive to inhibition. Ropeginterferon alfa-2b is a next generation pegylated interferon-α-2b with high tolerability and clinical activity in patients with MF, however, evidence of tolerability and activity in combination with fedratinib is lacking in this setting. The aim of the FEDORA trial is to assess tolerability, safety, and activity of fedratinib with ropeginterferon alfa-2b in patients with MF who require treatment to justify further investigation in a phase III trial. METHODS: FEDORA is a single arm, multicentre, open-label, Bayesian phase II trial to assess tolerability, safety, and activity of fedratinib with ropeginterferon alfa-2b aiming to recruit 30 patients. Patients with JAK2V617F positive primary or secondary MF, who are aged ≥ 18 years, have intermediate-1 with palpable splenomegaly of > 5cm, intermediate-2, or high-risk disease according to the Dynamic International Prognostic Scoring System (DIPSS), and who require treatment are eligible. The primary outcome is tolerability, whereby the combination is deemed intolerable in a patient if drug-related toxicities in the first four months of treatment lead to: either drug being discontinued; delays in treatment exceeding 28 consecutive days; or death. FEDORA uses a within-patient dose escalation regimen to ensure each patient reaches a personalised dose combination that is acceptable. DISCUSSION: FEDORA is using a Bayesian trial design and aims to provide evidence of the tolerability, safety, and activity of combining fedratinib with ropeginterferon alfa-2b upon which the decision as to whether a phase III trial is warranted will be based. TRIAL REGISTRATION: EudraCT number: 2021-004056-42. ISRCTN: 88,102,629.
Predictive Performance of Cardiovascular Risk Scores in Cancer Survivors From the UK Biobank.
BACKGROUND: Cardiovascular preventive strategies are guided by risk scores with unknown validity in cancer cohorts. OBJECTIVES: This study aimed to evaluate the predictive performance of 7 established cardiovascular risk scores in cancer survivors from the UK Biobank. METHODS: The predictive performance of QRISK3, Systematic Coronary Risk Evaluation 2 (SCORE2)/Systematic Coronary Risk Evaluation for Older Persons (SCORE-OP), Framingham Risk Score, Pooled Cohort equations to Prevent Heart Failure (PCP-HF), CHARGE-AF, QStroke, and CHA2DS2-VASc was calculated in participants with and without a history of cancer. Participants were propensity matched on age, sex, deprivation, health behaviors, family history, and metabolic conditions. Analyses were stratified into any cancer, breast, lung, prostate, brain/central nervous system, hematologic malignancies, Hodgkin lymphoma, and non-Hodgkin lymphoma. Incident cardiovascular events were tracked through health record linkage over 10 years of follow-up. The area under the receiver operating curve, balanced accuracy, and sensitivity were reported. RESULTS: The analysis included 31,534 cancer survivors and 126,136 covariate-matched controls. Risk score distributions were near identical in cases and controls. Participants with any cancer had a significantly higher incidence of all cardiovascular outcomes than matched controls. Performance metrics were significantly worse for all risk scores in cancer cases than in matched controls. The most notable differences were among participants with a history of hematologic malignancies who had significantly higher outcome rates and poorer risk score performance than their matched controls. The performance of risk scores for predicting stroke in participants with brain/central nervous system cancer was very poor, with predictive accuracy more than 30% lower than noncancer controls. CONCLUSIONS: Existing cardiovascular risk scores have significantly worse predictive accuracy in cancer survivors compared with noncancer comparators, leading to an underestimation of risk in this cohort.
From pioneer to repressor: Bimodal foxd3 activity dynamically remodels neural crest regulatory landscape in vivo
The neural crest (NC) is a transient embryonic stem cell populations characterised by its multipotency and broad developmental potential. Here, we perform NC-specific transcriptional and epigenomic profiling of foxd3-mutant versus wild-type cells in vivo to define the gene regulatory circuits controlling NC specification. Together with global binding analysis obtained by foxd3 biotin-ChIP and single cell profiles of foxd3-expressing premigratory NC, our analysis shows that during early steps of NC formation, foxd3 acts globally as a pioneer factor to prime the onset of genes regulating NC specification and migration by re-arranging the chromatin landscape, opening cis-regulatory elements and reshuffling nucleosomes. Strikingly, foxd3 then switches from an activator to its canonical role as a transcriptional repressor. Taken together, these results demonstrate that foxd3 acts bimodally in the neural crest as a switch from 'permissive' to 'repressive' nucleosome/chromatin organisation to maintain 'stemness' and define cell fates.
Targeting GRPR for sex hormone-dependent cancer after loss of E-cadherin.
Sex inequalities in cancer are well documented, but the current limited understanding is hindering advances in precision medicine and therapies1. Consideration of ethnicity, age and sex is essential for the management of cancer patients because they underlie important differences in both incidence and response to treatment2,3. Age-related hormone production, which is a consistent divergence between the sexes, is underestimated in cancers that are not recognized as being hormone dependent4-6. Here, we show that premenopausal women have increased vulnerability to cancers, and we identify the cell-cell adhesion molecule E-cadherin as a crucial component in the oestrogen response in various cancers, including melanoma. In a mouse model of melanoma, we discovered an oestrogen-sensitizing pathway connecting E-cadherin, β-catenin, oestrogen receptor-α and GRPR that promotes melanoma aggressiveness in women. Inhibiting this pathway by targeting GRPR or oestrogen receptor-α reduces metastasis in mice, indicating its therapeutic potential. Our study introduces a concept linking hormone sensitivity and tumour phenotype in which hormones affect cell phenotype and aggressiveness. We have identified an integrated pro-tumour pathway in women and propose that targeting a G-protein-coupled receptor with drugs not commonly used for cancer treatment could be more effective in treating E-cadherin-dependent cancers in women. This study emphasizes the importance of sex-specific factors in cancer management and offers hope of improving outcomes in various cancers.
Detecting and quantifying clonal selection in somatic stem cells.
As DNA variants accumulate in somatic stem cells, become selected or evolve neutrally, they may ultimately alter tissue function. When, and how, selection occurs in homeostatic tissues is incompletely understood. Here, we introduce SCIFER, a scalable method that identifies selection in an individual tissue, without requiring knowledge of the driver event. SCIFER also infers self-renewal and mutation dynamics of the tissue's stem cells, and the size and age of selected clones. Probing bulk whole-genome sequencing data of nonmalignant human bone marrow and brain, we detected pervasive selection in both tissues. Selected clones in hematopoiesis, with or without known drivers, were initiated uniformly across life. In the brain, we found pre-malignant clones with glioma-initiating mutations and clones without known drivers. In contrast to hematopoiesis, selected clones in the brain originated preferentially from childhood to young adulthood. SCIFER is broadly applicable to renewing somatic tissues to detect and quantify selection.