Disease Models & Mechanisms最新文献

The intestine is a rich source of hormones that regulate metabolism. Among these are glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), both expressed by L-cells. These hormones play important roles in promoting satiety; however, how they are regulated transcriptionally is not known. ETS variant transcription factor 1 (ETV1) is expressed by L-cells, but its function remains unknown. Here, we examined Etv1 expression in single-cell RNA-sequencing (scRNA-seq) datasets from the mouse small intestine and from organoid cultures. To assess the functional role of ETV1, loss-of-function and overexpression experiments were performed in organoids. Gene expression was subsequently assessed with quantitative PCR and scRNA-seq. Our results confirmed Etv1 enrichment in the L-cell lineage both in vivo and in organoids. Furthermore, mutations in ETV1 led to a decrease in Pyy expression levels with no effect on Gcg levels or on overall cell composition and organoid morphology. Moreover, overexpression of ETV1 led to a modest, but specific, increase in Pyy levels. We thus identified ETV1 as a regulator of Pyy expression, illustrating, for the first time, how specific hormones in the L-cell lineage are transcriptionally regulated.

The necessity of reliable preclinical models for evaluating the efficacy of novel therapeutic strategies is imperative. Nevertheless, the degree to which tumor-bearing murine models represent the immunological characteristics of human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) has largely been unexplored. By utilizing single-cell RNA sequencing technology, our research elucidated that subcutaneous (SC) murine models more accurately reflect the early immunogenic phase of human HPV-positive OPSCC, marked by a stage-dependent increase in effector T-cell infiltration. By contrast, orthotopic (base of tongue, BOT) tumors exhibited a progressive decline of cytotoxic T cells and accumulation of myeloid-derived suppressive cells, paralleling the immune decrease observed in advanced, immune-excluded human tumors. Additionally, our drug responsiveness analysis indicated that early-stage BOT models more accurately replicate the response to PDCD1 blockade, whereas late-stage SC models more accurately mirror the response to CTLA4 blockade akin to human samples. Our findings provide pivotal insights into the suitability of murine models for the preclinical assessment of immunotherapies in HPV-positive OPSCC.

14-3-3 proteins impact protein-protein interactions (PPIs) that regulate neuronal functions. The 14-3-3θ isoform is protective in models of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Human PD and DLB brains show increased 14-3-3θ phosphorylation at S232. To understand the impact of 14-3-3θ phosphorylation on brain PPIs, we performed affinity purification-mass spectrometry using S232 phospho-mutant knock-in mouse models. Proteins binding 14-3-3θ in Cre control cortical lysates were enriched in proteins involved in neuronal morphogenesis and microtubule dynamics. We found a dramatic decrease in proteins binding to 14-3-3θ in S232D mice compared to S232A mice. Axonal trafficking associated with these differentially binding proteins. Live imaging of acidic vesicles in axons revealed reduced net velocity in S232A and S232D neurons compared to that in Cre controls. In S232D neurons, this was due to a dramatic increase in vesicle pausing, while S232A neurons showed reduced segmental velocity, suggesting disrupted dynein motility. We conclude that 14-3-3θ phosphorylation fine tunes axonal transport of acidic vesicles. Disruption of axonal transport with aberrant phosphorylation observed in PD and DLB could contribute to impaired clearance of aggregated proteins in these disorders.

Low-density lipoprotein-related receptor 5 (LRP5) is an LDLR family member with well-defined roles in mediating Wnt signaling. Its domain structure includes four LDLR class B and three LDLR class A repeats. Class B repeats mediate binding with Wnt ligands and other effectors, while the role of the LRP5 class A repeats, known to interact with apolipoproteins within the LDLR, is unclear. Complete loss of the LRP5 gene in humans causes osteoporosis pseudoglioma, a syndrome characterized by early-onset osteoporosis and changes in retinal vascularization. We and others have previously created mice and rats completely deficient in LRP5 and reported the presence of bone and retinal vascularization defects. In this study, we created an allele of Lrp5 in mice in which the entire protein except for the class A repeats is present and expressed from the endogenous locus. Unlike in vitro studies using ectopic overexpression of LRP5, our in vivo data demonstrate that the class A repeats are essential for several normal LRP5 functions, including bone homeostasis, retinal vascularization and mammary gland development - phenotypes similar to those observed in Lrp5 null mice.

Per- and polyfluoroalkyl substances (PFAS) are often called 'forever chemicals'. This colloquialism reflects that many PFAS are recalcitrant to environmental and metabolic degradation, leading to long environmental and biological half-lives. This persistence, a concerning characteristic of these synthetic substances, is also a reason they are used in many products and processes. Most PFAS have physical-chemical properties that enable them to withstand extreme conditions and make them useful for a range of applications, including as surfactants or coatings that confer oil-, stain- and water-repellency. This combination of persistence and wide use has resulted in extensive environmental contamination and the presence of PFAS in living organisms, leading to use restrictions. Increasing evidence of health effects has also led to implementation of health protective guidelines. In the United States, federal regulations enacted in 2024 limit levels of six PFAS in drinking water; in the European Union, a proposed restriction would control use, import and production of the vast majority of PFAS. This Perspective article summarizes how knowledge of toxicological hazards and health-related costs of PFAS has progressed in recent years, leading to actions to restrict PFAS uses.

Human cerebellar development is unique and cannot be fully replicated in animal models. Although human stem cell-derived cerebellar organoid models are increasingly being applied to model cerebellar diseases, their potential to provide insight into normal human cerebellar development remains underexplored. Here, we used CRISPR-based gene editing in cerebellar organoids as an approach for modelling specific features of early human cerebellar development. Forkhead box protein P2 (FOXP2) is a transcription factor associated with speech and language development that is highly expressed in the developing brain. However, little attention has been directed to the study of FOXP2 in the early developing cerebellum. We generated a fluorescent FOXP2 reporter line in human induced pluripotent stem cells to enable the characterisation of FOXP2-expressing cells during cerebellar organoid differentiation. Through transcriptomic profiling of FOXP2 reporter cerebellar organoids and cross-referencing with existing cerebellar datasets, we describe the expression and identify potential downstream targets of FOXP2 in the early developing human cerebellum. Our results highlight expression of FOXP2 in early human Purkinje cells and cerebellar nuclei neurons, and the vulnerability of these cell populations to neurodevelopmental disorders.

Japanese encephalitis virus (JEV), a leading cause of viral encephalitis in Asia and the Western Pacific, is regulated by type I interferon (IFN) signaling pathway, in which STAT2 is critical. However, the exact role of STAT2 in JEV-mediated IFN evasion remains unclear. Existing murine models of JEV infection predominantly employ high viral titers to induce encephalitis and primarily use immunocompetent or IFN receptor-deficient mice, limiting their use to study the IFN evasion mechanisms of JEV. To address this, we developed a humanized STAT2 mouse model (NCG-hSTAT2+/+) and infected it with 10³ PFU of JEV-p3. These mice exhibited severe encephalitis resembling clinical human infections, characterized by elevated viral load, and increased proinflammatory cytokines. Especially, they presented typical neurological symptoms, such as activated astrocytes and distinct neuropathological changes. This suggests that NCG-hSTAT2+/+ mice exhibit higher susceptibility to JEV and more-severe neurological symptoms, which is consistent with the clinical manifestations observed in human patients. This mouse model significantly advances the study of JEV pathogenesis, the therapeutic evaluation of this infection and the role human STAT2 has in neuroinvasion and immune evasion.

Glycolysis and the tricarboxylic acid cycle (TCA) cycle are reprogrammed in cancer cells to meet bioenergetic and biosynthetic demands, including by engagement with the extracellular matrix (ECM). However, the mechanisms by which the ECM engagement reprograms core energy metabolism is still unknown. We showed that the canonical cell-ECM adhesion protein focal adhesion kinase (FAK, also known as PTK2) and, specifically, its kinase activity, is driving cellular energetics. Using a mouse stem cell model of glioblastoma, we showed that deletion of the FAK gene simultaneously inhibits glycolysis and glutamine oxidation, increases mitochondrial fragmentation, elevates phosphorylation of the mitochondrial protein MTFR1L at serine residue 235 (S235) and triggers a mesenchymal-to-epithelial transition. These metabolic and structural changes arise through altered contractility of actomyosin, as shown by myosin light chain type II (MYL2, also known as MLC2) phosphorylated (p) at S19. This process can be reversed by Rho-kinase (ROCK) inhibitors revealing mechanotransduction pathway control of both mitochondrial dynamics and glutamine oxidation. FAK-dependent metabolic programming is associated with regulation of cell migration, invasive capacity and tumour growth in vivo. Our work describes a previously unrecognised FAK-ROCK axis that couples mechanical cues to the rewiring of energy metabolism, linking cell shape, mitochondrial function and malignant behaviour.