Advances in stem cell-derived brain organoids, enabled by the generation of human reprogrammed pluripotent stem cells, have significantly expanded the repertoire of models available for brain tumour research. These approaches have predominantly been applied to glioblastoma and medulloblastoma, leveraging brain region-specific cerebral/cortical or cerebellar organoids, respectively. Organoids have the potential to close the gap between current two-dimensional cell-based brain tumour models and patients, while helping to address the limitations of animal models. In this At a Glance article, we outline current stem cell-derived organoid-based brain tumour models and how they have expanded our understanding of paediatric and adult brain tumours, including their onset, heterogeneity and treatment. We also describe how these organoids are currently being refined toward more accurate, clinically relevant models and highlight future directions to improve their translatability.
Acute kidney injury (AKI) is a common and severe morbidity following extracorporeal cardiopulmonary resuscitation (ECPR), particularly in children, where AKI is associated with a 4-fold increased risk of death. Research into the mechanisms and treatment of ECPR-induced AKI is hampered by the lack of relevant translational models. In this study, we developed a pediatric swine model of ECPR-induced AKI and defined the histological and transcriptomic changes seen in the kidney following ECPR. Four infant swine underwent hyperkalemic cardiac arrest (5, 10, 15, or 20 min) followed by 4 hours of ECMO. Mechanically ventilated animals (n=9) were used for comparison. ECPR animals demonstrated progressive histologic, biomarker, and physiologic kidney injury with increasing cardiac arrest time. All ECPR-exposed animals demonstrated a distinct transcriptomic response compared to controls, with 1,433 differentially expressed genes covering a range of biologic systems including oxidative stress, renal angiogenesis and solute channel formation, protein folding/misfolding, and ribosome biogenesis. This study demonstrates the ability to model ECPR-induced kidney injury in a titratable fashion and to serve as a platform for mechanistic and therapeutic studies for this important morbidity.
Cushing's disease (CD), the most common endogenous Cushing's syndrome, is caused by activating mutations in the ubiquitin-specific protease 8 (USP8) gene. These mutations drive adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas and hypercortisolism. Clinical manifestations include muscle weakness, osteopenia, cataracts and cardiovascular dysfunction. To investigate the pathogenic mechanisms of USP8 gain of function, we generated a conditional transgenic mouse model expressing human USP8 (referred to as hUSP8) carrying the most prevalent activating mutation in CD adenomas (p.S718del). Systemic expression of hUSP8S718del in mice induced diffuse corticotroph hyperplasia of ACTH+ cells, rather than pituitary microadenomas, and did not lead to hypercortisolemia. Despite preservation of the hypothalamic-pituitary-adrenal axis, transgenic mice developed skeletal muscle atrophy, bone abnormalities, corneal keratitis with cataracts and cardiac dysfunction. Notably, myocardial-specific expression of hUSP8S718del recapitulated cardiac defects seen in mice with ubiquitous expression, demonstrating the direct role of USP8 activation in the heart. These findings show that expression of a clinically relevant USP8 gain-of-function mutation in mice recapitulates key features of a USP8-associated syndrome. Our results reveal tissue-specific effects of USP8 beyond pituitary tumorigenesis and identify a direct contribution of USP8 activation to cardiac pathology.
Dilated cardiomyopathy (DCM) is a leading cause of heart failure with notable sex differences in susceptibility and progression. Although sarcomere mutations such as cardiac actin ACTC1 p.T126I contribute to familial DCM, the in vivo effects and sex-specific consequences remain unclear. We generated a zebrafish model carrying the orthologous Acta1b p.T126I mutation and conducted longitudinal, sex-stratified analyses of cardiac function, morphology and gene expression. Mutants showed variable onset of cardiac dysfunction, with progressive DCM, pericardial effusion, ventricular dilation, and reduced survival in adults. Female mutants exhibited earlier and sustained diastolic dysfunction, greater cardiac remodeling and significantly lower survival compared to males, revealing pronounced sexual dimorphism. Molecular profiling at a pre-symptomatic stage identified upregulation of nppb, downregulation of hypertrophic transcription factors (gata4, mef2ca), and sex-specific alterations in calcium handling genes (serca2, pln1, slc8a1a) and proteostasis regulators (hsf1, bag3). Older stages demonstrated a variable shift of individuals’ gene expression to cardiac remodeling and decompensation. These findings demonstrate that the Acta1b p.T126I mutation drives progressive, sex-specific DCM in zebrafish, highlighting biological sex as a critical modifier of sarcomeric cardiomyopathy progression and targeted therapy development.
Cystic fibrosis (CF) is a severe, life-limiting genetic disorder caused by mutations in the CFTR gene, which lead to defective epithelial ion transport, abnormally thick mucus and multi organ dysfunction, predominantly affecting the lungs, pancreas and digestive system. Despite significant advances in patient care, the complex interplay between CFTR dysfunction, chronic infection and persistent inflammation remains a major therapeutic challenge. In this context, animal models are indispensable for elucidating the cellular and molecular mechanisms underlying CF pathogenesis and accelerating drug discovery. Here, we review the relevance of the zebrafish (Danio rerio) as a powerful and complementary preclinical model for CF research. In particular, we highlight the unique advantages of zebrafish, including its highly conserved innate immune system and optical transparency, which together enable in vivo visualization of host immune responses under CF-like conditions at subcellular resolution. We further summarize how Cftr-deficient zebrafish models have provided key insights into the increased susceptibility to CF-relevant pathogens, disease mechanisms affecting the pancreas and the reproductive system, and the deleterious neutrophil-driven inflammation that characterizes CF. Finally, we discuss the potential of the zebrafish model for the identification and validation of novel therapeutic strategies to treat infectious and inflammatory lung pathology in CF, and outline future directions to expand its translational impact in CF research.
Cardiomyopathy is an important manifestation in patients with fatty acid oxidation disorders and represents a major cause of morbidity and early mortality in mitochondrial trifunctional protein (TFP) deficiency. Although a mouse model carrying the TFP β-subunit p.Met404Lys mutation (βTFP-deficient) has been described, cardiac involvement in this model has not been systematically characterized. Here, we combined cardiac histology and multiparametric cardiac MRI (CMR) to define myocardial structure, function, and tissue characteristics in this mouse model. Histological analysis with automated whole-slide collagen quantification revealed myocardial fibrosis with collagen deposition in mutant hearts, and CMR demonstrated increased myocardial extracellular volume in both male and female homozygous mutants. Homozygous males showed reduced ejection fraction, impaired systolic strain, and increased left ventricular end-systolic volume, indicating systolic dysfunction. Male mice were more severely affected than females and exhibited reduced survival. Together, these findings demonstrate that βTFP-deficient mice develop fibrotic cardiomyopathy with systolic dysfunction, reproducing important cardiac features observed in human TFP deficiency. This work establishes the model as a relevant platform for investigating disease mechanisms and therapeutic strategies for cardiomyopathy in TFP deficiency.
High-fat diet (HFD) combined with streptozotocin (STZ) is widely used to model type 2 diabetes (T2D) in rodents, but is often associated with high mortality, non-responders, and inconsistent outcomes. STZ is conventionally administered using body weight-adjusted dosing (mg/kg), despite evidence that heavier animals, including HFD-fed mice, exhibit more severe glycaemic responses. Here, we performed metabolic phenotyping in chow- and HFD-fed C57BL/6J mice treated with low or high fixed doses (mg instead of mg/kg) of anomer-equilibrated STZ. HFD combined with low-dose STZ induced a stable T2D-like phenotype characterized by sustained obesity, moderate hyperglycaemia, insulin resistance, and partial β-cell loss, with low inter-individual variability. In contrast, high-dose STZ induced a T1D-like phenotype with extensive β-cell loss. A semi-mechanistic mathematical model was developed and validated against independent experimental data, reproducing the observed dynamics of fasting glucose in response to fixed-dose STZ. The model further predicted that weight-adjusted (mg/kg) dosing could introduce variability in glycaemic responses, particularly in HFD-fed mice. Together, these results demonstrate that fixed-dose, anomer-equilibrated STZ induces a stable T2D-like phenotype, providing an alternative to conventional weight-adjusted dosing in HFD-fed mice.
Dominant and recessive mutations in the human CSF1R gene are associated with microglial deficiency in the brain and severe neurodegenerative disease, known as CSF1R-related leukoencephalopathy (CRL). Dominant and recessive Csf1r mutations have been generated in mice, rats, zebrafish and chicken, providing models of the complete or partial microglial loss seen in patients. The impact of Csf1r mutations in inbred mice depends upon genetic background. For example, Csf1r mutants in the C57BL/6J strain are uniquely susceptible to perinatal mortality and hydrocephalus. Congenital microglial deficiency in a range of animal models does not influence postnatal brain development but is associated with age-dependent neuropathology that resembles CRL, indicating that microglial deficiency contributes to disease. None of the available models fully recapitulates the severe functional motor and cognitive impairments seen in patients, raising questions about species differences and the relative contributions of genetic and environmental modifiers. However, they have provided platforms to test ways to repopulate the brain with functional microglia. Here, we briefly review the genetic basis for CRL and evidence of variable penetrance. We also assess experimental models that can enable the development of therapeutic strategies.
Autosomal dominant mutations in HSPB1 can cause type 2 Charcot-Marie-Tooth disease, a progressive neuromuscular disorder. HSPB1 is a small, ATP-independent chaperone that functions in protein folding, stabilisation and stress protection as well as regulating intracellular processes such as the cytoskeleton. How diverse mutations in HSPB1 exert progressive neuromuscular defects is unclear. Using a transgenic Caenorhabditis elegans model, we examined 3 distinct HSPB1 mutations and determined that mutant HSPB1 caused an early defect in neuromuscular signalling strength as assayed by aldicarb sensitivity. Our data point to the effects being presynaptic in origin and unrelated to expression differences of mutant HSPB1 compared with the wild-type protein. In contrast, the early defect in neuromuscular signalling may be a result of a general loss of small chaperone function. We also identified a progressive effect, whereby age-dependent changes to neuromuscular signalling are accelerated in worms expressing mutant HSPB1. These effects were not mirrored by a general loss of small chaperone function; however, wild-type HSPB1 expression strikingly protected against progressive defects seen in controls. These results indicate a possible progressive mechanism for HSPB1-dependent neuromuscular defects.
Systemic hypoxia - a reduction in oxygen supply to all tissues and organs - occurs in many physiological and pathological conditions, including fetal development, high-altitude exposure, and disorders such as sleep apnea and respiratory disease. Under these conditions, whole-body physiology must adapt to ensure proper tissue functioning and survival. Although extensive research has characterized how individual cells sense and adapt to low-oxygen conditions, the mechanisms that coordinate whole-body responses to systemic hypoxia remain poorly understood. In this study, we uncovered an inter-organ signaling response mediated by the cytokine Unpaired-3 (Upd3), a functional homolog of human interleukin-6 (IL-6), that is important for systemic hypoxia tolerance in Drosophila. We demonstrated that hypoxia rapidly induces Upd3 expression and activates JAK/STAT signaling in larvae and adults. Interestingly, we discovered a sex-specific requirement for this pathway, with females, but not males, requiring Upd3 for hypoxia survival. We also identified the intestine as a critical source of hypoxia-induced Upd3 and showed that gut-derived Upd3 signals to the fat body and oenocytes to mediate hypoxia tolerance by promoting expression of nitric oxide synthase, the FGF ligand Branchless and the kinase Hipk. Furthermore, we revealed an unexpected role for the canonical hypoxia response transcription factor HIF-1α/Sima as a molecular brake, which prevents lethal Upd3 overproduction, revealing that hypoxia survival requires precise cytokine dosage control. Our findings define a gut-to-fat body signaling axis that coordinates systemic hypoxia adaptation, highlighting cytokine-mediated inter-organ communication as a mechanism for whole-body adaptation to low oxygen, with potential relevance to hypoxia-related human pathologies.
Transplantation of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes offers new opportunities for myocardial repair after infarction. However, as demonstrated in large-animal model studies, such therapy also brings translational challenges, including arrhythmias arising from abnormal spontaneous beating of the engrafted cells or irregular conduction due to poor electrical coupling between host and transplanted tissue. Addressing these issues will have important implications for improving the safety and efficacy of regenerative therapies. This Review summarizes the fundamental mechanisms governing cardiac electrical activity and highlights recent technological advancements for triggering and imaging myocardial electrical function. We focus on emerging experimental platforms that overcome limitations of traditional whole-heart mapping approaches, including organotypic myocardial tissue slices combined with high-resolution optical mapping and optogenetic stimulation. We further discuss recent technological and biological developments in the field of cell transplantation for cardiac repair and examine strategies to manage post-transplant arrhythmia risk, with a particular focus on enhancing graft maturation and electrical integration to accelerate the safe and effective clinical translation of cardiac cell therapies. Finally, we describe recent clinical trials involving transplantation of hiPSC-derived cells into damaged hearts.
Background: Early and accurate risk stratification of patients suspected of serious infection is essential for improving outcomes, but existing diagnostic and predictive tools have limited accuracy. The objective was to compare the performance of an FDA-authorized AI diagnostic test, the Sepsis ImmunoScore, against widely available biomarkers and clinical tools for diagnosis of sepsis and prediction of in-hospital mortality and intensive care unit (ICU) admission. Methods: This multicenter observational study included 6027 adult patients suspected of infection across 7 U.S. hospital sites. The Sepsis ImmunoScore’s predictive performance was compared to the sequential organ failure assessment (SOFA) score, procalcitonin (PCT), C-reactive protein (CRP), Systemic Inflammatory Response Syndrome (SIRS) score, National Early Warning Score (NEWS), and quick SOFA (qSOFA). Primary outcomes included sepsis as defined by Sepsis-3 criteria, in-hospital mortality, and ICU admission. Predictive accuracy was assessed using area under the receiver operating characteristic curve (AUC), and 95% confidence intervals were generated and hypothesis testing conducted using the bootstrap method. Results: The Sepsis ImmunoScore demonstrated statistically significant superior performance across all outcomes. For sepsis prediction, the Sepsis ImmunoScore achieved an AUC of 0.82, compared to SOFA (0.72), procalcitonin (PCT) (0.70), C-reactive protein (CRP) (0.61), SIRS (0.59), NEWS (0.69), and qSOFA (0.67). For in-hospital mortality prediction, the Sepsis ImmunoScore achieved an AUC of 0.80, outperforming SOFA (0.72), PCT (0.67), CRP (0.58), SIRS (0.60), NEWS (0.72), and qSOFA (0.69). For ICU admission, the Sepsis ImmunoScore reached an AUC of 0.74, superior to SOFA (0.63), PCT (0.64), CRP (0.54), SIRS (0.60), NEWS (0.70), and qSOFA (0.65). All differences between the Sepsis ImmunoScore and comparators were statistically significant. Conclusions: The Sepsis ImmunoScore significantly improved predictive accuracy for sepsis, in-hospital mortality, and ICU admission compared to six conventional clinical scores and biomarkers. This AI-based tool may enhance risk stratification and clinical decision-making, potentially leading to more timely sepsis interventions and improved outcomes.
In chronic diseases, multiple tissue components at a shared interface often deteriorate concurrently, and disease progression may depend on interactions among these failures rather than on any single defect. Multi-tissue organoid models can mimic disease-relevant pathology in vitro, but the field lacks a simple framework for comprehensive interrogation. Here, we propose mesoscale maladaptation as an operational concept for multi-tissue disease modelling, defined as a synergistic decline in interdependent functions that can occur between two or more tissue elements. To detect maladaptation, we introduce a stepwise workflow that identifies the failing tissue elements, defines directionality of potential interdependence between these elements and compares combined perturbations with single perturbations to evaluate synergistic decline. We apply this framework to intestinal neuromuscular, hepatic sinusoidal, blood-brain barrier and tumour-neural interfaces, but it can be extrapolated to other organs and systems. This framework will illuminate future directions for in vitro complex disease modelling by enriching biological insights to disentangle progressive pathology, shifting the focus from localised biological failures to concurrent multi-tissue failures that produce synergistic pathology.
Dosage imbalance of dual specificity tyrosine phosphorylation regulated kinase 1A (DYRK1A) is a feature of several neurodevelopmental and neurodegenerative diseases, including Down syndrome, DYRK1A syndrome, autism spectrum disorders, Alzheimer's disease and Parkinson's disease. Thus, manipulating DYRK1A activity in the brain has emerged as a potential therapeutic target for neurological disorders. Several DYRK1A inhibitors have shown promise for improving cognition in rodent models of Down syndrome and Alzheimer's disease, for example, but the ability of these inhibitors to affect DYRK1A levels or activity in relevant human cells has not been established. We filled this gap by testing the effects of a new DYRK1A inhibitor on trisomy 21 induced pluripotent stem cell (iPSC)-derived neural progenitor cells and neurons, in which DYRK1A expression and activity are increased. Our results demonstrated that Leucettinib-21, a potent and selective low-molecular-mass pharmacological inhibitor of DYRK1A, decreases DYRK1A activity in human trisomy 21 iPSC-derived neural progenitor cells and cortical neurons. Leucettinib-21 reduces DYRK1A activity in a relevant human disease model, supporting future human trials.
Background: Plasma biomarkers are promoted as scalable tools for the staging of Alzheimer's disease (AD), yet head-to-head comparisons against the clinical scales used to define diagnostic labels remain scarce. Reported gains from machine learning fusion of clinical and biomarker features may reflect label circularity rather than biological signals, and quantifying this circularity is a central aim of the present work. Methods: From the Alzheimer's Disease Neuroimaging Initiative (ADNI), we assembled 655 participants (CN = 296, MCI = 168, and AD = 191) with concurrent plasma biomarkers (pT217, Aβ42/40, NfL, and GFAP), clinical scales (MMSE, CDR-SB, and FAQ), APOE genotype, and demographics. Three pre-specified feature sets (clinical-only, biomarker plus demographic-genetic, and full fusion) were compared across four classifiers (Logistic Regression, SVM, Random Forest, and XGBoost) using repeated, nested cross-validation (5-fold × 3 outer, 5-fold inner) with balanced class weighting. Because the external Center for Neurodegeneration and Translational Neuroscience (CNTN) cohort (n=130) measures pT181 rather than pT217 and lacks Aβ42/40, external evaluation used a separate reduced feature panel (NfL, GFAP, APOE, age, sex, and education), not the proposed pT217-inclusive panel. Results: Clinical scales alone reached a three-class AUC-OVR of 0.9539±0.0041, and fusion reached 0.9559±0.0046, an indistinguishable gain. Because MMSE, CDR-SB, and FAQ partly determine ADNI diagnostic labels, both estimates are circularity-inflated upper bounds and do not reflect independent classification power. Independent of this circularity, the internal plasma plus demographic-genetic model still achieved AUC-OVR =0.7455±0.0150, with pT217 as the dominant contributor. Pairwise discrimination was excellent for CN vs. AD (1.0000) and MCI vs. AD (0.9739) but markedly weaker for CN vs. MCI (0.9302 for fused and 0.6972 for plasma only). The separate reduced-feature model, which contains neither pT217 nor Aβ42/40, transferred to CNTN with AUC-OVR =0.702 (95% CI 0.635-0.764). Conclusions: Apparent fusion gains in ADNI are largely a consequence of label circularity. After removing the circular clinical features, the internal pT217-inclusive plasma model supports three-class CN/MCI/AD screening at AUC ≈0.74 and a reduced panel without pT217 transfers to an independent cohort at AUC ≈0.70. These values provide a realistic performance estimate for blood-based AD staging under the current feature set, diagnostic label structure, and cohort design, and richer feature sets or pathology-anchored labels may shift this estimate. MCI detection remains the principal bottleneck.
