Cell Biology and Toxicology最新文献

Ovarian aging significantly contributes to the decline of the female reproductive system, adversely affecting fertility and endocrine homeostasis. To address the challenges posed by reproductive aging, natural products have shown promising preventive and therapeutic effects. Here, we investigated the beneficial effects of natural compound celastrol on ovarian development and aging, together with its underlying mechanisms. We found that celastrol administration at a concentration of 3 mg/kg promoted follicle development in young mice and enhanced porcine oocyte maturation, while regulating granulosa cell proliferation and apoptosis. In 12-month-old mice (equivalent to middle-aged adults), celastrol exhibited similar beneficial effects. Transcriptomic analysis revealed that differentially expressed genes post-celastrol treatment were associated with steroid biosynthesis, estrogen signaling pathways, type 2 diabetes, insulin secretion, meiosis, and apoptosis. Additionally, insulin receptor substrate 1 (IRS1), an adapter protein in insulin signaling, was shown to advance puberty in young mice and to facilitate oocyte maturation. Overexpression of IRS1 in oocytes promoted follicular development and oocyte maturation, resulting in enhanced steroid hormone levels, whereas IRS1 knockdown inhibited these processes. Our findings indicate that celastrol may regulate ovarian development and aging by modulating IRS1 expression and its related pathways, suggesting celastrol as a novel small-molecule compound targeting IRS1, and offering new perspectives for potential therapeutic strategies against reproductive aging and infertility.

Sepsis-induced lung injury (ALI) is a critical condition characterized by excessive immune responses and tissue damage. Previous evidence has underscored an upregulation pattern of DNA methyltransferase 1 (DNMT1) in sepsis. This study reveals the key role of DNMT1 in modulating regulatory T cell (Treg) activity in septic ALI. A septic mouse model was generated through cecal ligation and puncture. Treatment with either DNMT1 antagonist Thioguanine (ThG) or AAV-sh-DNMT1 significantly reduced immune cell infiltration, reduced production of pro-inflammatory cytokines, and increasing production of anti-inflammatory cytokines in the bronchoalveolar lavage fluid (BALF) of mice, alongside improved lung pathology and integrity. Furthermore, the DNMT1 inhibition or silencing significantly enhanced population of FOXP3⁺ Tregs in the BALF and lung tissue. Similar trends were observed in mice with specific DNMT1 deletion in CD4⁺ T cells (DNMT1-CD4-ko). Regarding the mechanism, we observed that DNMT1 represses transcription of forkhead box O1 (FOXO1) by recruiting RUNX family transcription factor 1 (RUNX1) to the FOXO1 promoter. FOXO1-specific knockout in CD4⁺ T cells reduced anti-inflammatory activity of Tregs. Additionally, administration of the CD25 antibody exacerbated sepsis-induced ALI in DNMT1-CD4-ko mice. Collectively, these findings illustrate that targeting DNMT1 interacts with RUNX1 to repress transcription of FOXO1, which reduces immunomodulatory activity of Tregs and augments inflammatory cascades in septic lung injury.

Sepsis-induced acute kidney injury (SI-AKI) is a severe condition with limited therapeutic options, resulting in poor prognosis. Ferroptosis exacerbates the damage caused by SI-AKI, but the mechanisms regulating ferroptosis, especially those involving ubiquitination regulators, remain poorly understood. Here, we used a lipopolysaccharide (LPS)-induced human kidney organoid (HKO) model to investigate ferroptosis in SI-AKI. RNA sequencing (RNA-seq) analysis of control and LPS-treated HKOs revealed USP18 as the only upregulated ubiquitin-specific protease (USP) in response to LPS. Further investigations showed that depletion of USP18 significantly reduced ferroptosis in LPS-induced HKOs. To explore the mechanism underlying USP18's pro-ferroptotic role, we screened four ferroptosis-related drivers and identified STING1 as the key interacting protein with USP18. Mechanistically, USP18 directly binds to STING1, deubiquitinates it, and prevents its proteasomal degradation in HKOs. Overexpression of STING1 in USP18-deficient HKOs exacerbated ferroptosis, indicating that STING1 is crucial for mediating USP18's ferroptosis-promoting function in LPS-induced HKOs. Together, these findings establish that USP18-STING1 axis plays role in LPS-induced ferroptosis in HKOs, illuminating that targeting USP18-STING1 could provide neoteric therapeutic approach for treating SI-AKI.

Cardiac fibrosis is a critical pathological process following myocardial infarction (MI), contributing to adverse cardiac remodeling and dysfunction. This study investigates the role of N-acetyltransferase 10 (NAT10), an RNA acetyltransferase, in mediating cardiac fibrosis through the N4-acetylcytidine (ac4C) modification of transforming growth factor beta receptor type 1 (TGFBR1) mRNA. Using a mouse model of MI, we demonstrated elevated levels of NAT10 and total ac4C RNA in left ventricular tissues, correlating with increased cardiac fibrosis. Echocardiographic analysis revealed significant impairment in cardiac contractile function, which was further validated by histological assessments using H&E and Masson staining. In vitro studies showed that TGF-β stimulation of cardiac fibroblasts led to enhanced NAT10 expression and myofibroblast differentiation, as evidenced by α-SMA staining. The role of NAT10 was further elucidated through fibroblast-specific knockout experiments, where the absence of NAT10 markedly attenuated cardiac fibrosis and improved echocardiographic parameters at eight weeks post-MI. Additionally, NAT10 knockout resulted in decreased mRNA and protein levels of fibrotic markers such as Collagen I and III, alongside reduced ac4C RNA modification. Additionally, we established that NAT10 enhances the stability of TGFBR1 mRNA via ac4C modification, as supported by RNA immunoprecipitation and luciferase assays. TGFBR1 overexpression countered the effects of NAT10 knockout, restoring fibrotic responses in both in vivo and in vitro models. These findings suggest that NAT10 plays a pivotal role in cardiac fibrosis following MI by regulating TGFBR1 mRNA stability through ac4C modification, thereby presenting potential therapeutic targets for mitigating cardiac fibrosis in post-MI patients.

Methyltransferase 1 (METTL1) is currently regarded as a key tRNA m⁷G writer. Recent studies indicate its potential role in carcinogenesis via increased m⁷G modification to stabilize tRNA and upregulate tRNA expression. Cadmium-induced stress triggers the assembly of stress granules (SGs) and production of tRNA-derived stress-induced RNAs (tiRNAs). However, whether METTL1 is involved in the formation of cadmium-induced SGs and its mechanism are still unclear. Here, we demonstrated that METTL1 promotes cadmium-induced SGs formation. Mechanistically, METTL1 not only upregulates SG's core protein Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) translation through tRNAs m⁷G modification, but also enhances expression of one m⁷G-modified tiRNA, m⁷G-3' tiRNA-Met^CAT (mtiRM), which affects SGs assembly. Together, the findings concluded that the promotional effect of METTL1 on cadmium-induced SGs formation jointly through G3BP1 translation and mtiRM expression, thus providing insights into an intimate link between SGs and tumorigenesis.

Background: The guanine nucleotide exchange factor RASGRF1 actively acts in a broad range of human cancers, including thyroid cancer (THCA). This study defined the activity of RASGRF1 in THCA progression and elucidated the m6A modification mechanism governing dysregulation of RASGRF1.

Methods: Expression analyses were performed by immunoblotting, immunohistochemistry (IHC) or quantitative PCR. Cell growth was evaluated by colony formation and EdU proliferation assays. Animal experiments tested the function of RASGRF1 in xenograft growth. The conditioned medium (CM) of THCA cells was used to treat THP-1-differentiated macrophages. Cell apoptosis and CD206⁺ macrophages were assessed by flow cytometry. Cell invasiveness and migratory ability were detected by transwell assays. The influence of FTO in RASGRF1 was evaluated by RNA immunoprecipitation (RIP) and MeRIP assays.

Results: RASGRF1 was upregulated in human THCA. RASGRF1 depletion retarded THCA cell growth, motility, invasiveness and promoted cell apoptosis and ferroptosis in vitro, as well as diminished the growth of TPC1 THCA xenograft tumors in vivo. Moreover, RASGRF1 depletion diminished M2 polarization and migration of THP-1-differentiated macrophages. Mechanistically, FTO reduced RASGRF1 mRNA stability via an m6A-dependent mechanism. FTO upregulation suppressed THCA malignant behaviors, promoted cell ferroptosis and reduced macrophage M2 polarization and migration through repression of RASGRF1.

Conclusion: Our findings suggest that FTO-mediated the instability of RASGRF1 mRNA diminishes THCA-related macrophage M2 polarization and THCA progression. Anti-RASGRF1 strategies may be useful for the treatment of THCA.

Background: This study investigates how mP6/Rg3 micelles modulate ABCB1 expression to induce ferroptosis in oral cancer stem cells (CSC) and enhance oral cancer outcomes.

Methods: Micelles targeting CD44 peptide P6 were prepared and characterized using TEM and immunofluorescence. Biocompatibility was evaluated through LIVE/DEAD staining and CCK-8 assays. Impact on oral cancer CSC was assessed through in vitro and OSCC mouse model studies using transcriptomic profiling, proteomic analysis, and metabolomic screening.

Results: mP6/Rg3 micelles exhibited good biodegradability, inhibiting CSC proliferation and migration. Integrated multi-omics analysis highlighted ABCB1 as a pivotal modulator in OSCC. Functional assays in cell and animal models validated micelles promote ferroptosis in CSC by inhibiting ABCB1, improving OSCC pathology.

Conclusions: Targeting ABCB1 with mP6/Rg3 micelles and regulating CD44 presents a promising approach to suppress oral cancer progression by impacting CSC and tumor metabolic pathways. This study offers crucial molecular insights for new therapeutic strategies in oral cancer treatment.

Osteoporosis (OP) is a systemic skeletal disorder marked by reduced bone density and deterioration of trabecular microstructure. Recent studies have established ferroptosis as a major contributor to osteoporotic bone loss; however, the specific molecular mechanisms underlying this process remain incompletely understood. In this study, RNA sequencing revealed decreased expression of protein tyrosine kinase 2 (PTK2) in OP, while bioinformatics analyses identified a significant association between PTK2 and the ferroptosis-related gene P53. Mechanistically, lysine acetyltransferase 8 (MOF) acts as a key acetyltransferase for P53 acetylation. We found that PTK2 negatively regulates ferroptosis by competitively binding with MOF, thereby inhibiting both the acetylation and succinylation of P53 at the K120 site. This inhibition restores the transcriptional expression of fibronectin 1 (FN1). Using computer-aided molecular docking, we identified vaccarin-a bioactive small-molecule compound from the Selleck.cn natural product library-as a PTK2-targeting agent. Vaccarin not only suppressed erastin-induced ferroptosis but also enhanced the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Finally, we demonstrated that adenoviral overexpression of PTK2 (ADV-PTK2) or treatment with Vaccarin attenuated ovariectomy (OVX)-induced ferroptosis and osteoporosis in mice. These findings highlight PTK2 as a promising therapeutic target for OP and suggest that targeting PTK2-mediated ferroptosis inhibition may offer a novel therapeutic approach for osteoporosis management.

Objective: To investigate the therapeutic potential of Asperosaponin VI (ASA VI) from Clematis chinensis in mitigating osteoarthritis (OA) progression by modulating the AMPK-SIRT3 pathway, specifically addressing ER stress, mitochondrial dysfunction, and chondrocyte apoptosis.

Methods: In vitro studies were conducted using tert-Butyl hydroperoxide (TBHP)-treated chondrocytes to evaluate the effects of ASA VI on apoptosis, extracellular matrix (ECM) degradation, and mitochondrial function. In vivo studies were performed using a Destabilization of the Medial Meniscus (DMM) rat model to assess cartilage protection and joint integrity. Key molecular markers of ER stress (GRP78, CHOP, ATF4) and mitochondrial biogenesis (PGC-1α, TFAM, NRF-2) were analyzed through Western blotting and PCR. Histological assessments, including Safranin O and H&E staining, were used to evaluate joint architecture and cartilage degradation, while Osteoarthritis Research Society International (OARSI) scores quantified the extent of cartilage destruction.

Results: ASA VI treatment significantly enhanced chondrocyte viability and reduced apoptosis, as evidenced by a decrease in TUNEL-positive cells. It also preserved cartilage matrix integrity by upregulating Collagen II and Aggrecan, while reducing MMP-13 expression. Mechanistic studies revealed that ASA VI activates the AMPK-SIRT3 pathway, reducing ER stress and enhancing mitochondrial biogenesis, as indicated by increased PGC-1α, TFAM, and NRF-2 expression. Improvements in mitochondrial function were confirmed by increased ATP production and the preservation of mitochondrial membrane potential. In the DMM rat model, ASA VI treatment led to a significant reduction in cartilage degradation and OARSI scores, with histological analysis confirming improved joint architecture. Molecular analysis further validated the reduction in ER stress markers, linking these improvements to the activation of the AMPK-SIRT3 pathway.

Conclusion: ASA VI from Clematis chinensis offers a promising therapeutic approach for OA by leveraging the AMPK-SIRT3 pathway to alleviate ER stress and mitochondrial dysfunction. This comprehensive protective mechanism contributes to reduced chondrocyte apoptosis and preserved cartilage integrity, highlighting ASA VI's potential as a novel disease-modifying agent in OA management.