Disease Models & Mechanisms最新文献

Mycobacterium abscessus is a fast-growing non-tuberculous mycobacterium that can cause chronic lung disease leading to rapid decline in lung function. There are no FDA-approved therapies for this disease. To support the development of new treatments, an animal model of M. abscessus lung infection that is simple to implement and requires minimal resources is crucial to encourage broad adoption. We present a mouse model using the immunocompetent BALB/c strain, which is both widely available and cost effective. Since BALB/c mice naturally clear M. abscessus infections, immunosuppression is necessary to sustain bacterial growth in the lungs. Once-weekly intraperitoneal injections of the immunosuppressant cyclophosphamide at 250 mg/kg successfully induced proliferation of M. abscessus during the acute phase, followed by stabilization characteristic of chronic infection. This model demonstrated the efficacy of imipenem - an antibiotic commonly used in clinical settings - by significantly reducing bacterial burdens, mirroring their effects in human cases. However, clofazimine, which is also used to treat this disease, was bacteriostatic. This cost-effective and accessible mouse model is suitable for diverse laboratory environments and provides a valuable tool for preclinical evaluation of treatments for M. abscessus lung disease.

Fungal diseases of the central nervous system (CNS) are associated with severe neurological damage and death in immunocompromised hosts, yet they remain neglected in research and policy. Neuroinflammation, a common clinical feature of fungal infection, has been implicated as a key driver of brain injury, but the mechanisms underlying its contribution to pathology are not well understood. The aim of this Review is to discuss the double-edged role of neuroinflammation in the pathogenesis of fungal infections. We provide an overview of the immune barriers that protect the CNS from fungal infection, the fungal strategies that enable immune evasion and neuroinvasion, and the complex mechanisms underlying the development of neuroinflammation during fungal infection. Finally, we explore how both insufficient and excessive neuroinflammatory responses drive neuropathology, and we conclude by outlining current challenges as well as potential directions for advancing future research in this overlooked field.

Continuous passaging of cancer cell lines can drive phenotypic and genotypic divergence, potentially compromising the reliability of such models. In this study, we show that two late-passage strains (S1 and S2) of ovarian cancer cell line SKOV3, although authenticated via short tandem repeat (STR) profiling as identical, exhibit substantial differences in morphology, transcriptomic signatures, ability to form 3D cultures and chemotherapeutic responses. Notably, S1 formed compact 3D spheroids and exhibited enhanced epithelial-mesenchymal transition (EMT) pathway activity, whereas S2 displayed a more proliferative, MYC-driven phenotype with larger spheroid structures requiring higher seeding densities. Transcriptomic analysis revealed pathways associated with hypoxia, EMT and angiogenesis in 3D culture, highlighting the complexity introduced by dimensionality in tumour modelling. Critically, S1 showed higher sensitivity to doxorubicin than S2 (IC50 of 0.12 µM versus 1.28 µM, P=0.0001), indicating how clonal evolution can confound drug-response assays. Ultimately, our findings suggest that although STR profiling remains essential for cell line authentication, functionally distinct subpopulations can arise and coexist within the same culture, and their isolation may reveal divergent phenotypes that compromise reproducibility in preclinical cancer research.

The importance of microtubule stability and microtubule-associated proteins in the etiology of Shwachman-Diamond syndrome (SDS) has been highlighted in recent studies. In one patient with SDS, a novel MAP7D1:c.601C>T, p.R201W variant has been identified. In this study, the causality of this variant in the pathogenesis of SDS was investigated. Mutation in the microtubule-binding domain of MAP7D1 caused disruption of its interaction with microtubules. SDS fibroblasts exhibited a decreased cell size with reduced microtubule density, and mitotic defects, including multipolar or bipolar unstable spindles, lagging chromosomes, and shortened inter-centrosomal distance. Additionally, ribosomal protein S14 (RPS14) accumulated within incorrectly dividing SDS fibroblasts. To further evaluate whether these abnormalities are directly attributable to the MAP7D1 mutation, mitotic processes were investigated through genetic manipulations of MAP7D1 in T98G glioblastoma and HEK293T embryonic kidney cell lines. Consistent with data from SDS fibroblasts, similar phenotypes were detected upon overexpression of mutant MAP7D1 and depletion of MAP7D1. Our findings revealed that the MAP7D1 mutation acts as a loss-of-function mutation and contributes to SDS pathogenesis by disrupting microtubule dynamics and ribosomal protein regulation, identifying MAP7D1 as a gene with substantial impact for SDS.

Metastasis remains a leading cause of morbidity and mortality in patients diagnosed with cancer. A variety of in vitro and in vivo approaches have been employed to study the individual steps of the metastatic cascade. However, these methodologies are sometimes limited in their ability to recapitulate the biological complexity and heterogeneity of human tumor biology. As a result, significant knowledge gaps still exist regarding the development, growth and evolution of treatment resistance in metastatic tumors. In this Perspective, we discuss the benefits and drawbacks of current, widely used techniques to model metastatic disease. We also highlight novel approaches utilized in recent studies to confront the limitations posed by classic modeling techniques. Ultimately, we provide suggestions for ensuring scientific rigor and reproducibility in metastasis studies, and we propose key areas of focus for developing next-generation models of metastasis.

Mitochondria are dynamic organelles that are critical for energy production in high-demand tissues, such as the brain and muscle, with fusion and fission maintaining network integrity. The dysregulation of these processes underlies pathologies, such as neurodegenerative diseases. Ribosomal S6 kinases (RSK1-4) are effectors of extracellular signal-regulated kinases (ERKs), with roles in cell survival and metabolism. Here, we show that RSKs are essential for mitochondrial health. In human cells, siRNAs targeting any RSK isoform (RSK1-4) induced mitochondrial fragmentation and reduced viability. In Drosophila melanogaster, CRISPR-mediated loss of S6kII (the sole RSK orthologue) caused mitochondrial dysfunction and tissue degeneration in high-energy-demand organs, including the indirect flight muscle and brain, accompanied by autophagic activation. Notably, we rescued these defects by expressing human RSK4, underscoring functional conservation. Our findings establish RSKs as critical regulators of mitochondrial integrity, linking ERK signalling to organelle dynamics. This work identifies RSKs as regulators of mitochondrial health in energy-demanding tissues, providing insights into the mechanisms underlying neurodegeneration and strategies to target ERK/RSK-driven mitochondrial dysfunction.

Methionine sulfoxide reductases (MSRs) are enzymes responsible for catalyzing the reduction of methionine sulfoxides. We previously demonstrated that variants in human MSRB3, an MSR family member, are associated with profound autosomal recessive prelingual non-syndromic deafness, DFNB74. To better understand the role of MSRB3 in the auditory pathway, we generated complete Msrb3 gene knockout mice. The Msrb3-deficient mice showed profound deafness by postnatal day 16, which was accompanied by morphological abnormalities including altered stereocilia bundle shape and cuticular plate degeneration, followed by hair cell apoptotic death. Although the absence of MSRB3 primarily affected the actin cytoskeleton, rootlets were present, and the localization of major F-actin stereocilia-core proteins was unaltered. Biochemical assays demonstrated that wild-type MSRB3, but not MSRB3 harboring p.Cys89Gly, the same variant reported for DFNB74, can repolymerize oxidized actin. Consistent with these results, we observed a decreased ratio of reduced/total actin in the inner ears of Msrb3 knockout mice. These data suggest a protective role for MSRB3 in the maintenance and maturation of stereocilia and hair cells, a conserved mechanism aimed at maintaining actin redox dynamics in these sensory cells.

Idiopathic pulmonary fibrosis (IPF) is a rare and fatal lung disease caused by progressive damage to alveolar epithelial cells, leading to abnormal activation of mesenchymal cells. The PRRX1 transcription factor (TF) has been found to be reactivated in IPF and was previously identified as a key mesenchymal TF in pulmonary fibrosis. In this study, we utilized the Prrx1:CreERT2; Rosa26iTomato murine transgenic line to further characterize the Prrx1-positive cell lineage in healthy and fibrotic lungs. The Prrx1 limb enhancer (Prrx1enh) was undetectable by immunohistochemistry in uninjured lung tissue. However, during the fibrotic phase in the bleomycin model of pulmonary fibrosis, Prrx1enh became activated, marking a population of cells that differentiated into mesenchymal progeny. To investigate further, we conducted reprogramming of these subpopulations after conditional and inducible Prrx1 loss of function. Prrx1 loss in these cells led to worsened fibrosis, indicating that this specific cell population has antifibrotic properties. Our findings reveal a previously unrecognized subpopulation of Prrx1-positive mesenchymal cells that are activated during fibrogenesis. These cells could serve as targets for future therapies aimed at mitigating fibrotic progression in IPF.