Tissue & cell最新文献

The kynurenine pathway is the principal route of tryptophan metabolism in the brain, generating several neuroactive metabolites, including kynurenic acid (KYNA). KYNA functions as both a neuromodulator and a neuroprotective compound, and its dysregulation has been associated with numerous neurological and psychiatric disorders. Kynurenine aminotransferase-2 (KAT-2) is the key enzyme responsible for KYNA synthesis, yet its precise cellular localization in the mouse brain remains insufficiently characterized. In this study, we systematically compared KAT-2 expression in primary astrocytic, microglial, and neuronal cultures derived from mouse brain, complemented by in situ immunolabeling of brain sections. Immunocytochemistry combined with quantitative colocalization analysis revealed that KAT-2 is expressed in all three major brain cell types, with significant overlap with cell type-specific markers. Furthermore, KAT-2 immunoreactivity was largely restricted to the soma, showing a perinuclear distribution in glial cells and partial extension into dendritic compartments in neurons. These findings provide the first parallel characterization of KAT-2 distribution across astrocytes, microglia, and neurons in the mouse brain. Overall, our results indicate that KAT-2 is widely expressed in neural cells, a finding that supports the hypothesis that KAT-2 contributes broadly to kynurenine metabolism. Taken together, our findings provide a foundation for future studies aimed at defining the cell type-specific functional roles of KAT-2.

Background: Anaplastic thyroid carcinoma (ATC) is an exceptionally aggressive thyroid cancer subtype. Protein arginine methyltransferases (PRMTs), particularly PRMT1, have emerged as key regulators in cancer biology. This study investigates the therapeutic potential of targeting PRMT1 as a novel strategy for ATC intervention.

Methods: ATC samples were stratified into high and low PRMT1 expression groups based on PRMT1 levels. Dot blot assay was utilized to assess m6A methylation levels, while RT-PCR quantified the level of m6A-related proteins. Pearson correlation analysis evaluated the relationship between PRMT1 and Wilms'tumor 1-associating protein (WTAP) expression. Mitochondrial membrane potential was measured using the TMRE probe, and Western blotting was used to analyze cuproptosis markers. The m6A modification level of PRMT1 was determined via meRIP-qPCR. Additionally, a xenograft tumor model was established to validate the role of the PRMT1/WTAP pathway in vivo.

Results: The mRNA and protein expressions of PRMT1 were significantly upregulated in ATC clinical samples and cell lines compared to normal controls. ATC samples were stratified into high and low PRMT1 expression groups using the median PRMT1 protein expression level (determined by immunohistochemistry) as the cutoff. Elevated m6A modification levels were observed in the high PRMT1 expression group. A positive correlation was identified between PRMT1 and WTAP mRNA expression in ATC clinical samples. In vitro studies demonstrated that PRMT1 regulates cuproptosis as the primary mode of cell death in ATC. PRMT1 silencing led to a reduction in mitochondrial membrane potential and increased expression of cuproptosis markers. WTAP knockdown reduced the m6A modification of PRMT1 and decreased its mRNA stability.

Conclusion: WTAP regulated the m6A modification and mRNA stability of PRMT1. The WTAP/PRMT1 signaling axis modulated cuproptosis, thereby influencing ATC progression. These findings highlighted the potential of targeting the WTAP/PRMT1 pathway as a therapeutic strategy for ATC.

Background: Chronic intermittent hypoxia (CIH) is a typical feature of obstructive sleep apnea (OSA), and CIH exposure can lead to the development of lung injury (LI). While tempol can be used to treat CIH-induced LI, its regulatory mechanism remains unclear. Therefore, the present study aimed to investigate the potential mechanism through which tempol improves the progression of CIH-induced LI.

Methods: In vitro and in vivo CIH-associated LI models were constructed using intermittent hypoxia (IH)-induced BEAS-2B cells and C57BL/6 mice. Cell viability was determined via the CCK-8 assay, and changes in related proteins were detected via Western blot analysis. The levels of Fe^2 + , malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) were detected via kits, and the level of reactive oxygen species (ROS) was detected via fluorescence microscopy and flow cytometry. Lung tissue injury was evaluated by hematoxylin and eosin (HE) staining and Masson's trichrome staining.

Results: After IH induction, the levels of ferroptosis-related indicators (GPX4, FTH1, and SLC7A11), SOD and GSH were decreased in BEAS-2B cells and mouse lung tissues, whereas the levels of Fe²⁺, ROS and MDA were increased in BEAS-2B cells and mouse lung tissues. In addition, IH decreased BEAS-2B cell viability and aggravated lung tissue damage and fibrosis in mice. The addition of the Fer-1 ferroptosis inhibitor or tempol weakened the effects of IH, indicating that tempol treatment improved the progression of CIH-induced LI through the inhibition of ferroptosis. Mechanistically, tempol activated the Nrf2/GSH signaling axis through suppressing TLR4 expression, thereby inhibiting ferroptosis and improving CIH-induced LI.

Conclusion: Tempol promotes Nrf2/GSH signaling through suppressing TLR4 expression, thereby inhibiting ferroptosis and alleviating CIH-induced LI.

The therapeutic potential of Wnt/β-catenin signaling to enhance proliferation in differentiated cardiomyocytes remains underexplored, particularly in genetically diverse disease models. Here, we systematically evaluated whether pharmacological Wnt activation overrides genetic constraints to drive expansion of induced pluripotent stem cell-derived cardiomyocytes (iCMs) from healthy donors and inherited cardiomyopathy models (GAA-Pompe disease, RYR2-catecholaminergic polymorphic ventricular tachycardia, and KCNQ1-long QT syndrome type 1). Using a component-defined GiWi protocol, functionally mature iCMs were generated from a high-quality iPSC line with validated trilineage differentiation capacity. Longitudinal analysis of CHIR-induced Wnt/β-catenin activation demonstrated dose-dependent proliferative amplification, with CHIR-treated iCMs achieving > 400-fold monolayer expansion by passage 4 versus ∼8-fold in controls. Immunofluorescence quantification revealed significantly elevated Ki67⁺ /cTnT⁺ double-positive cardiomyocytes under CHIR treatment (∼20 % vs. ∼9 % in controls at passage 3). Strikingly, proliferative responses showed genetic neutrality: healthy iCMs exhibited ∼432-fold expansion compared to ∼406-fold in disease models (p = 0.72), with comparable Ki67⁺/cTnT⁺ ratios by passage 4 (healthy: ∼8.9 %; disease: ∼8.3 %). These findings demonstrate that timed Wnt activation overrides genetic lesions to enable disease-agnostic proliferation in differentiated iCMs. This genetic neutrality supports standardized regenerative strategies for genetically heterogeneous cardiomyopathies and arrhythmias, addressing a critical challenge in developing personalized cardiac therapies.