Cell Biology and Toxicology最新文献

Ischemic stroke (IS) constitutes a leading driver of mortality and morbidity worldwide, with neuronal apoptosis representing a key pathological process. Accordingly, our objective was to delve into the implications of a novel signaling axis of the m6A methyltransferase METTL7B, lncRNA-MIR22HG, and JARID2 in driving neuronal apoptosis throughout cerebral ischemia/reperfusion (I/R) injury (CIRI). Mice subjected to middle cerebral artery occlusion/reperfusion (MCAO/R) and N2a cells exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) were, respectively, established as in vivo and in vitro I/R models. METTL7B was markedly up-regulated after I/R and enhanced the m6A methylation and stability of lncRNA-MIR22HG, significantly prolonging its transcript half-life and amplifying its biological effects on neuronal fate. Stabilized lncRNA-MIR22HG suppressed the ubiquitin-mediated degradation of JARID2, thereby increasing JARID2 abundance and activity. Elevated JARID2 promoted the assembly of the p53/p300/MDM2 transcriptional complex, which in turn up-regulated the levels of pro-apoptotic genes, ultimately exacerbating neuronal apoptosis alongside ischemic brain injury. Functionally, METTL7B overexpression aggravated neurological deficits, infarct volume, and neuronal apoptosis in vivo, whereas METTL7B knockdown alleviated ischemic damage and conferred robust neuroprotection. Collectively, these findings define a novel METTL7B/lncRNA-MIR22HG/JARID2 signaling axis that integrates RNA methylation, lncRNA stabilization, proteostasis, and transcriptional activation of apoptosis, and highlight METTL7B as a potential novel target for therapeutic strategies aimed at preventing and treating ischemic stroke.

Parkinson's disease (PD) is characterized by dopaminergic neuronal loss, often associated with mitochondrial dysfunction and impaired mitophagy. Here, we investigated the role of HUWE1, an E3 ubiquitin ligase, in regulating mitophagy and neuronal survival in a cellular PD model. HUWE1 promoted mitophagy, whereas its depletion sensitized SH-SY5Y cells to 6-hydroxydopamine (6-OHDA)- and 1-methyl-4-phenylpyridinium (MPP⁺)-induced cytotoxicity and mitochondrial dysfunction. Notably, both toxins downregulated HUWE1, suggesting that loss of HUWE1 contributes to dopaminergic vulnerability. Conversely, HUWE1 overexpression preserved mitochondrial integrity and enhanced mitophagy under neurotoxic stress. Importantly, BL-918, a ULK1 activator that promotes AMBRA1 recruitment, facilitated HUWE1-mediated mitophagy in SH-SY5Y cells. BL-918 treatment significantly attenuated 6-OHDA- and MPP⁺-induced neurotoxicity and protected mitochondrial function via HUWE1 activation. Collectively, these findings identify HUWE1 as a key mechanistic regulator of mitophagy linked to dopaminergic neuronal vulnerability, and provide a conceptual framework for future investigations examining its role in PD-relevant model systems.

Osteoporosis, characterized by excessive osteoclast activity and bone resorption, is closely linked to mitochondrial respiration. The long non-coding RNA Gm5532 (Gm5532) has been implicated in osteoclast differentiation, but its role in mitochondrial function remains unclear. This study aimed to elucidate the mechanism by which Gm5532 regulates bone resorption through iron metabolism and mitochondrial respiration, focusing on its interaction with iASPP and the NRF2 signaling pathway. Here, we show that Gm5532 KO alleviates bone loss in aged, ovariectomized, and iron-overloaded mice by reducing osteoclast formation and activity. Mechanistically, Gm5532 directly interacts with the RNA-binding protein iASPP. This interaction modulates the KEAP1/NRF2 axis, leading to the destabilization of NRF2. Gm5532 KO enhances iASPP-KEAP1 binding, thereby stabilizing NRF2 and upregulating its target genes: Ftl, Fth, and Fpn1. This cascade reduces the intracellular labile iron pool. Iron deficiency suppresses mitochondrial biogenesis and respiration, and ultimately, inhibites osteoclast differentiation. In summary, Gm5532 functions as a critical regulator of bone resorption through its modulation of iron homeostasis and mitochondrial respiration. Our study uncovers a novel Gm5532-iASPP-NRF2 signaling axis that links iron metabolism to mitochondrial respiration and osteoclast function, offering a promising potential therapeutic target for osteoporosis.

Ferritinophagy, a selective autophagic process mediated by nuclear receptor coactivator 4 (NCOA4), plays a central role in maintaining cellular iron homeostasis by degrading ferritin and releasing stored iron. Under physiological conditions, this process dynamically regulates iron storage and utilization, thereby preventing both iron deficiency and iron overload. However, under pathological conditions such as chronic inflammation, oxidative stress, and harmful environmental exposures, aberrant activation of ferritinophagy leads to excessive ferritin degradation and abnormal expansion of the cytosolic labile iron pool. This, in turn, drives the accumulation of iron-dependent reactive oxygen species and lipid peroxidation, lowering the threshold for ferroptosis initiation, exacerbating tissue injury, and promoting disease progression. Thus, the pathological significance of ferritinophagy lies not only in iron mobilization itself but also in its close coupling with ferroptosis. This "ferritinophagy-ferroptosis axis" has emerged as a key framework for understanding the link between iron dysregulation and disease pathogenesis. In recent years, increasing evidence has shown that this axis is repeatedly activated in various chronic respiratory diseases (CRDs), where it exerts a pivotal role in disease onset and progression. This review systematically summarizes the molecular mechanisms of NCOA4-mediated ferritinophagy and highlights the potential pathogenic role of the ferritinophagy-ferroptosis axis in different CRDs, aiming to provide a theoretical basis for identifying novel therapeutic strategies and intervention targets.

Objective: The GTPase RhoA is known as a regulator involved in cartilage degeneration and subchondral bone remodeling related to osteoarthritis (OA). However, its specific role in synovial macrophages, the key immune cells of OA related tissues, remains entirely unexplored.

Methods: Herein, the RhoA expression in human and mouse OA synovium was analyzed. A macrophage-specific RhoA conditional knockout (cKO) mouse model was generated. Histological staining, OARSI scoring, and micro-CT were used to assess cartilage damage, while Western blot, immunofluorescence staining, and ELISA assessed changes in cellular function. Transcriptome sequencing and validation of signaling pathways were conducted using tissues and cells from patients with OA and OA mice.

Results: The collected results indicate that RhoA expression was significantly upregulated in synovial macrophages from OA patients and mice, correlating with disease severity. Contrary to its reported role in chondrocytes or endothelial cells, macrophage-specific RhoA deletion exacerbated OA, demonstrating enhanced cartilage destruction, subchondral bone loss, and synovitis. RhoA-deficient macrophages exhibited a pro-inflammatory M1 polarization and secreted high levels of IL-17C. This cytokine was necessary and sufficient to induce chondrocyte senescence, as evidenced by increased p53/p21, ROS, mitochondrial dysfunction, and suppressed autophagy, via activation of the PI3K/AKT/mTOR pathway. Mechanistically, RhoA ablation in macrophages activated the Hippo pathway effectors YAP/CCN2, leading to IL-17C transcription, independently of the canonical ROCK pathway.

Conclusion: In conclusion, present study reveals a previously unrecognized, protective role for macrophage RhoA in OA. It functions as a critical brake on a novel YAP-IL-17C axis, thereby preserving chondrocyte. This study redefines RhoA's role in joint homeostasis and nominates IL-17C as a potential therapeutic target for OA.

Repeated exposure to ketamine leads to mental behavioral disorders and cognitive deficits in mice. As a neurotransmitter receptor, dopamine receptor 1 (DRD1) is involved in mental regulation and memory formation. However, the role of DRD1 in ketamine's behavioral disorder and neurotoxicity remains unclear. We found that seven-day ketamine exposure induced anxiety-like, depressive-like behavior and cognition dysfunction in mice. DRD1 activation can produce anxiety-like behavior similar to that induced by ketamine. Furthermore, DRD1 activation synergistically exacerbates this effect of ketamine, and DRD1 antagonism partially attenuates the anxiety-like behavior and further aggravated the depressive-like behavior induced by ketamine. Moreover, ketamine induced HT22 cell apoptosis by DRD1 dependent inhibition of Akt/Gsk3β phosphorylation. DRD1 agonist synergistically enhanced the apoptosis induced by ketamine, while DRD1 antagonist or the apoptosis inhibitor partially reversed this apoptosis in vitro. In vivo assay found that ketamine promotes neuronal apoptosis in the hippocampus and prefrontal cortex of mice, and antagonizing DRD1 partially attenuates ketamine-induced apoptosis. In contrast, cell-specific knockdown of DRD1 in neuronal cells exacerbated ketamine-induced neuronal apoptosis and anxiety-like behavior. In summary, ketamine regulates DRD1 to suppress Akt/Gsk3β phosphorylation, inducing neuronal apoptosis, ultimately leading to anxiety-like behaviors in mice.

Engineered nanoparticles (ENPs), defined as nanoscale materials with at least one dimension between 1 and 100 nm, exhibit multifunctional and tunable physicochemical properties, that are at the center of several innovative fields. However, ENPs may induce a variety of biochemical reactions upon entry into organisms that could be a threat to human health. Therefore, a systematic evaluation of the toxicity of ENPs is essential. Quantitative structure-activity relationship (QSAR) is a practical in vitro modeling approach used to evaluate the toxicity of nanoparticles. In this study, we established the nanometric QSAR (Nano-QSAR) modelling based on cell membrane damage of ENPs to HepaRG cells. The toxicity data of ENPs and related 2D descriptor information were collected from the NanoCommons Knowledge Base. Periodic table descriptors of the elements were calculated using the Elemental Descriptor Calculator software. A multiple linear regression (MLR) model was constructed, and subsequently combined with read-across (RA) descriptors to establish the Nano-quantitative read-across structure-activity relationship (Nano-q-RASAR) model. Furthermore, machine learning (ML) algorithms were applied to optimize the predictive performance of the models. All models were validated according to the stringent OECD QSAR validation guidelines. Finally, a series of true external ENPs without experimental values were autonomously designed, and predicted using the best GB-Nano-QSAR model. Overall, this study can provide efficient and reliable predictions for the cell membrane damage of ENPs and a detailed theoretical explanation of their toxicity mechanism, which is of practical value for the toxicity assessment of ENPs.

Acute myeloid leukemia (AML)-derived bone mesenchymal stem cell (MSC) exosomes have been confirmed to have a positive effect on AML progression. This study aim to reveal the underlying molecular mechanism by which AML-MSC-derived exosomes promotes AML progression. AML-MSC was isolated from the bone marrow aspirates of AML patients. After incubated with AML-MSC, AML cell functions were analyzed. The expression levels of methyltransferase-like 14 (METTL14), homeobox A3 (HOXA3), WNT family member 7B (WNT7B) and glycolysis-related markers were examined. Exosomes were isolated from AML-MSC and then the obtained exosomes were co-cultured with AML cells. AML-MSC co-culturing could enhance AML cell proliferation and glycolysis, while repress cell apoptosis. METTL14 was upregulated in exosomes from AML-MSC, which could be ingested by AML cells. METTL14 could enhance HOXA3 mRNA stability via promoting its m6A modification. Knockdown of exosomal METTL14 from AML-MSC inhibited AML cell growth and glycolysis, while were reversed by HOXA3. In addition, HOXA3 bound to WNT7B promoter to increase its transcription, and WNT7B overexpression also eliminated si-HOXA3-mediated inhibitory on AML cell growth and glycolysis. Animal study revealed that knockdown of exosomal METTL14 from AML-MSC reduced AML tumorigenesis by decreasing HOXA3 and WNT7B expression. AML-MSC-derived exosomal METTL14 facilitated AML cell growth and glycolysis by activating the HOXA3/WNT7B axis, providing a new mechanism for understanding AML-MSC-derived exosomes to promote AML progression.

Colorectal cancer (CRC) remains one of the leading causes of cancer-related deaths worldwide, largely due to late-stage diagnosis and limited efficacy of current therapies. 5-Fluorouracil (5-FU) is the standard chemotherapeutic agent used in CRC treatment; however, its effectiveness is often hampered by resistance, toxicity, and suboptimal outcomes in advanced-stage tumors. Recent evidence suggests that gut microbiota-derived short-chain fatty acids (SCFAs) exert anticancer effects and may hold promise as therapeutic adjuvants. In this study, we investigated the potential of a physiologically relevant mixture of SCFAs to enhance the efficacy of 5-FU against CRC. Using a combination of 2D monolayer cultures, 3D models, and the in vivo chicken chorioallantoic membrane (CAM) assay, we demonstrated that SCFAs positively affect the antitumor effects of low-dose 5-FU. SCFAs contributed to the inhibition of CRC cell growth, proliferation, survival, and migration, with an overall increase of the anti-tumour effects observed across the different models. The combined treatment led to a significant reduction in tumour size in the CAM assay, contributing for an improvement of the effects of 5-FU alone. To our knowledge, this is the first report showing that physiologically relevant SCFA combinations can be harnessed to improve the therapeutic index of 5-FU in CRC, in a context-dependent manner. These findings support the development of microbiota-targeted co-adjuvant strategies to optimize CRC chemotherapy, reduce treatment toxicity, and improve patient outcomes, which is important given the clinical interest in microbiome-chemotherapy interactions.

Alzheimer's disease (AD) is a heterogeneous disease with limited treatment efficacy. Identifying novel molecular targets and mechanisms is therefore crucial for developing therapeutic strategies. Zinc finger protein 36 (ZFP36) has not been reported in AD. This study found that the hippocampus of APP/PS1 mice showed ZFP36 upregulation. Using recombinant adeno-associated virus to overexpress ZFP36 improved the cognitive function of APP/PS1 mice, as assessed by Morris maze and Y maze tests. Furthermore, ZFP36 overexpression reduced Aβ deposition, expression of pro-inflammatory markers, and inhibited NLRP3 inflammasome activation in the hippocampus. These inhibitory effects of ZFP36 overexpression on the aforementioned proteins were also observed in Aβ₁₋₄₂-treated BV-2 cells. mRNA sequencing identified Z-DNA Binding Protein 1 (ZBP1) as a target of ZFP36. After ZFP36 overexpression, ZBP1 was downregulated in the hippocampus and Aβ_1-42-treated BV-2 cells. The interaction between ZFP36 and ZBP1 RNA was verified by RIP-PCR, and ZFP36 was shown to promote the degradation of ZBP1 mRNA. The inhibitory effects of ZFP36 on the NLRP3 inflammasome activation and microglial pro-inflammatory activation was reversed by ZBP1 overexpression. In summary, ZFP36 inhibits microglia pro-inflammatory and NLRP3 inflammasome activation through promoting the degradation of ZBP1 mRNA, thereby ameliorating cognitive deficits of APP/PS1 mice.