Disease Models & Mechanisms

Dystonia is supposed to arise from abnormalities in the motor loop of the basal ganglia; however, there is an ongoing debate regarding cerebellar involvement. We adopted the established cerebellar dystonia mice model by injecting ouabain to examine the contribution of the cerebellum. Initially, we examined whether the entopeduncular nucleus (EPN), substantia nigra pars reticulata (SNr), globus pallidus externus (GPe), and striatal neurons were activated in the model. Next, we examined whether dopamine D1 receptor agonists (D1 agonist) and dopamine D2 receptor antagonists (D2 antagonist) or selective ablation of striatal parvalbumin (PV) interneurons could modulate their involuntary movements...

Apoptosis is characterized by membrane blebbing and apoptotic body formation. Caspase cleavage of ROCK1 generates an active fragment that promotes actin-myosin mediated contraction and membrane blebbing during apoptosis. Expression of caspase-resistant non-cleavable ROCK1 (Rock1 NC) prolonged survival of mice that rapidly develop B cell lymphomas due to Eµ-Myc transgene expression. Eµ-Myc; Rock1 NC mice had significantly fewer bone marrow cells relative to Eµ-Myc mice expressing wild-type ROCK1 (Rock1 WT), which was associated with altered cell cycle profiles...

Dystroglycan (DG) is an extracellular matrix receptor consisting of an α- and a β-DG subunit encoded by the DAG1 gene. The homozygous mutation (c.2006G>T, p.Cys669Phe) in β-DG causes Muscle-Eye-Brain disease with multicystic leukodystrophy in humans. In a mouse model of this primary dystroglycanopathy, approximately two-thirds of homozygous embryos fail to develop to term. Mutant mice that are born undergo a normal postnatal development but show a late-onset myopathy with partially penetrant histopathological changes and an impaired performance on an activity wheel...

BACKGROUND: Administration of bone marrow (BM) derived cells to restore perfusion showed promising results in preclinical studies. However, clinical studies in chronic limb threatening ischemia (CLTI) demonstrated conflicting results. We conducted a systematic review and meta-analysis on preclinical studies to assess the efficacy of BM-derived cell administration in restoring relative perfusion in the hind limb ischemia model (HLI) and identify possible determinants of therapeutic efficacy...

Diabetes is a metabolic disorder characterized by high blood glucose levels and is a leading cause of kidney disease. Diabetic nephropathy has been attributed to dysfunctional mitochondria. However, many questions remain about the exact mechanism. The structure, function, and molecular pathways between mammalian podocytes and Drosophila nephrocytes are highly conserved, therefore we used flies on a high-sucrose diet to model type 2 diabetic nephropathy. The nephrocytes of high-sucrose diet flies showed significant functional decline and decreased cell size, associated with a shortened lifespan...

Duchenne muscular dystrophy (DMD) is a devastating monogenic skeletal muscle wasting disorder. While many pharmacological and genetic interventions have been reported in preclinical studies, few have progressed to clinical trials with meaningful benefit. Identifying therapeutic potential may be limited by availability of suitable preclinical mouse models. More rigorous testing across models with varied background strains and mutations may identify treatments for clinical success. Here we report the generation of a DMD mouse model, with a CRISPR-induced deletion within exon 62 of the Dmd gene, and the first generated in BALB/c mice...

O-GlcNAcylation is a protein modification that is critical for vertebrate development, catalysed by O-GlcNAc transferase (OGT) and reversed by O-GlcNAcase (OGA). Missense mutations in OGT have recently been shown to segregate with a X-linked syndromic form of intellectual disability, OGT-linked Congenital Disorder of Glycosylation (OGT-CDG). Although OGT-CDG suggests a critical role of O-GlcNAcylation in neurodevelopment and/or cognitive function, the underlying pathophysiologic mechanisms remain unknown. Here we report a mouse line that carries a catalytically impaired OGT-CDG variant...

Purkinje cell dysfunction disrupts movement and causes disorders such as ataxia. Recent evidence suggests that Purkinje cell dysfunction may also alter sleep regulation. Here, we used an ataxic mouse model generated by silencing Purkinje cell neurotransmission (L7Cre;Vgatfx/fx) to better understand how cerebellar dysfunction impacts sleep physiology. We focused our analysis on sleep architecture and electrocorticography (ECoG) patterns based on their relevance to extracting physiological measurements during sleep...

Interconnected mechanisms of ischemia-reperfusion (I-R) has increased the interest in I-R in vitro experiments using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). We developed a whole-cell computational model of hiPSC-CMs including the electromechanics, a metabolite-sensitive sarcoplasmic reticulum Ca2+-ATPase (SERCA), and an oxygen dynamics formulation to investigate I-R mechanisms. Moreover, we simulated the effect and action mechanism of Levosimendan (LEVO) that recently showed promising anti-arrhythmic effects in hiPSC-CMs in hypoxia...

Congenital heart defects, facial dysmorphism and intellectual development disorder (CHDFIDD) is associated with mutations in CDK13 gene, which encodes a transcription regulating Cyclin-dependent kinase 13 (CDK13). Here, we focused on development of craniofacial structures and analyzed early embryonic stages of CHDFIDD mouse models with hypomorphic mutation in Cdk13 gene, which exhibits cleft lip/palate and knockout of Cdk13 with stronger phenotype including midfacial cleft. Cdk13 was found to be physiologically strongly expressed in the mouse embryonic craniofacial structures, namely in the forebrain, nasal epithelium and maxillary mesenchyme...

De novo truncating variants in Fibrosin-like protein 1 (FBRSL1), a member of the AUTS2 gene family, cause a disability syndrome, including organ malformations such as heart defects. Here, we use Xenopus laevis to investigate whether Fbrsl1 plays a role in heart development. Xenopus laevis fbrsl1 is expressed in tissues relevant for heart development and morpholino-mediated knockdown of Fbrsl1 results in severely hypoplastic hearts. Our data suggest that Fbrsl1 is required for the development of the first heart field, which contributes to the ventricle and the atria, but not for the second heart field, which gives rise to the outflow tract...

Mitogen-Activated Protein 3 Kinase 1 (MAP3K1) has a plethora of cell-type specific functions not yet fully understood. Herein we describe a role for MAP3K1 in female reproductive tract (FRT) development. MAP3K1 kinase domain-deficient female mice exhibit imperforate vagina, labor failure, and infertility. These defects correspond with shunted Müllerian ducts (MDs), the embryonic precursors of FRT, that manifest as contorted caudal vagina and abrogated vaginal-urogenital sinus fusion in neonates. The MAP3K1 kinase domain is required for an optimal activation of the Jun-N-terminal kinase (JNK) and cell polarity in MD epithelium, and for up-regulation of WNT signaling in mesenchyme surrounding the caudal MD...

Reliable disease models are critical for medicine advancement. Here, we established a versatile human disease model system using patient derived extracellular vesicles (EVs), which transfer a pathology-inducing cargo from a patient to a recipient naïve model organism. As a proof of principle, we applied extracellular vesicles from serum of muscular dystrophy patients to C. elegans and demonstrated their capability to induce a spectrum of muscle pathologies including lifespan shortening and robust impairment of muscle organization and function...

Protein homeostasis is perturbed in aging-related neurodegenerative diseases called tauopathies, which are pathologically characterized by aggregation of the microtubule-associated protein tau. Transgenic Caenorhabditis elegans serve as a powerful model organism to study tauopathy disease mechanisms, but moderating transgenic expression level has proven problematic. To study neuronal tau proteostasis, we generated a suite of transgenic strains expressing low, medium, or high levels of Dendra2::tau fusion proteins by comparing integrated multicopy transgene arrays with single-copy safe-harbor locus strains generated by recombinase-mediated cassette exchange...

Snyder-Robinson Syndrome (SRS) is a rare X-linked recessive disorder caused by a mutation in the SMS gene encoding spermine synthase and aberrant polyamine metabolism. SRS is characterized by intellectual disability, thin habitus, seizure, low muscle tone/hypotonia, and osteoporosis. Progress towards understanding and treating SRS requires a model that recapitulates human mutations and disease presentations. Here, we evaluated molecular and neurological presentations in the G56S mouse model carrying a missense mutation in the Sms gene...

Seipin (BSCL2), a conserved endoplasmic reticulum protein, plays a critical role in LD biogenesis and regulating LD morphology, pathogenic variants of which are associated with Berardinelli-Seip Congenital Generalized Lipodystrophy Type 2 (BSCL2). To model BSCL2 disease, we generated an orthologous BSCL2 variant seip-1(A185P) in Caenorhabditis elegans. In this study, we conducted an unbiased chemical mutagenesis screen to identify genetic suppressors that restore embryonic viability in the seip-1(A185P) mutant background...

P4-ATPases flip lipids from the exoplasmic to cytoplasmic leaflet of cell membranes, a property crucial for many biological processes. Mutations in P4-ATPases are associated with severe inherited and complex human disorders. We have determined the expression, localization, and ATPase activity of four variants in ATP8A2, the P4-ATPase associated with the neurodevelopmental disorder known as cerebellar ataxia, mental retardation, and disequilibrium syndrome 4 (CAMRQ4). Two variants, Gly447Arg and Ala772Pro, harboring mutations in catalytic domains, expressed at low levels and mislocalized in cells...

The value of radiotherapy in the treatment of pancreatic cancer has been the subject of much debate but limited preclinical research. We hypothesise that the poor translation of radiation research into clinical trials of radiotherapy in pancreatic cancer is due, in part, to inadequate preclinical study models. Here, we have developed and refined methods for targeted irradiation in autochthonous mouse models of pancreatic cancer, using a small animal radiotherapy research platform. We tested and optimised strategies for administration of contrast agents, iohexol and the liver imaging agent Fenestra LC, to enable the use of computed tomography imaging in tumour localisation...

The tympanic membrane (or ear drum) sits at the interface between the middle and external ear. The membrane is composed of three layers: an outer ectodermally-derived layer, a middle neural crest-derived fibroblast layer with contribution from the mesoderm-derived vasculature, and an inner endodermally-derived mucosal layer. These layers form a thin sandwich that is often perforated as a consequence of trauma, pressure changes, or middle ear inflammation. During healing, cells need to bridge the perforation in the absence of an initial scaffold...

Effective gene therapy approaches have been developed for many rare diseases, including inborn errors of immunity and metabolism, haemoglobinopathies and inherited blindness. Despite successful pre-clinical and clinical results, these gene therapies are not widely available, primarily for non-medical reasons. Lack of commercial interest in therapies for ultra-rare diseases, costs of development and complex manufacturing processes required for advanced therapy medicinal products (ATMPs) are some of the main problems that are restricting access...