Undifferentiated/dedifferentiated endometrial carcinoma (UDEC) represents a rare but aggressive subtype of endometrial cancer characterized by chemoresistance. Notably, a considerable proportion of patients with UDEC who exhibit mismatch repair deficiency respond favorably to immunotherapy. Here, we identified mutations in the ribosomal protein L22 (RPL22) gene in 42
Age-related hearing loss (ARHL) is a prevalent and debilitating sensory deficit in the elderly, with chronic inflammation being a key pathogenic driver. The RNA methyltransferase METTL3, a primary mediator of N6-methyladenosine (m6A) modification, has been implicated in various aging-related diseases; however, its functional role and mechanism in ARHL remain poorly defined. ARHL models were established using 12-month-old C57BL/6 mice and by treating HEI-OC1 auditory cells with LPS and D-galactose. Auditory function and cochlear pathology were assessed through auditory brainstem response (ABR) thresholds and hematoxylin-eosin (H&E) staining, respectively. Inflammatory cytokine levels, gene and protein expression, were measured using ELISA, qPCR, Western blotting, and immunofluorescence. The molecular mechanism of METTL3 in inflammation was investigated using m6A RNA methylation quantification kit, RIP-qPCR analysis, and RNA stability assay. We found that both NFKBIA and METTL3 were significantly downregulated in the cochleae of ARHL mice. In HEI-OC1 cells, overexpression of NFKBIA suppressed the NLRP3 inflammasome and the pro-inflammatory NF-kappa B/IL-6/STAT3 axis. Furthermore, METTL3 overexpression mitigated NF-kappa B-mediated inflammation, an effect that was significantly attenuated upon NFKBIA knockdown. Mechanistically, METTL3 directly bound to NFKBIA mRNA and enhanced its stability through m6A modification. Critically, in ARHL mice, METTL3 overexpression restored NFKBIA levels, ameliorated hearing loss and cochlear damage, and suppressed the activation of the NLRP3 inflammasome and the NF-kappa B/IL-6/STAT3 pathway. Collectively, METTL3 mitigated ARHL by downregulating the NF-kappa B/IL-6/STAT3/NLRP3-mediated inflammatory responses through the enhancement of NFKBIA m6A modification.
Periodontal ligament stem cells (PDLSCs) are promising for oral and maxillofacial bone regeneration, but the mechanisms regulating their osteogenic differentiation remain unclear. This study aimed to determine the role of DLX2 and its regulation by ELK1, STUB1, and USP11 in PDLSCs. PDLSCs were genetically manipulated using lentiviral vectors. Osteogenesis was assessed by ALP and Alizarin Red S staining and expression of osteogenic markers. Protein interactions and ubiquitination were examined by co-immunoprecipitation and cycloheximide-chase assays. ELK1-dependent STUB1 transcription was verified by ChIP and luciferase reporter assays. A mouse mandibular defect model provided in vivo validation. DLX2 overexpression increased ALP activity, mineralization, and RUNX2, OSX, and OCN expression, whereas DLX2 silencing had opposite effects. DLX2-overexpressing PDLSCs enhanced bone formation in mandibular defects. STUB1 interacted with DLX2 and promoted its ubiquitination and degradation, whereas STUB1 knockdown stabilized DLX2. USP11 bound DLX2, reduced its ubiquitination, and stabilized the protein. ELK1 bound and activated the STUB1 promoter. ELK1 silencing reduced STUB1 expression, increased DLX2 and osteogenic markers, and enhanced bone formation; STUB1 overexpression partially reversed these effects. ELK1 suppresses PDLSC osteogenesis through STUB1-mediated DLX2 degradation, while USP11 stabilizes DLX2. This ELK1-STUB1-DLX2 axis may be a potential target for craniofacial bone regeneration. 1. DLX2 promotes osteogenic differentiation of PDLSCs and in vivo bone formation. 2. DLX2 undergoes STUB1-mediated ubiquitin-dependent degradation. 3. USP11 Inhibits Ubiquitin-Mediated Degradation and Enhances Stability of DLX2 in PDLSCs. 4. ELK1 Inhibits Osteogenic Differentiation of PDLSCs and in vivo bone formation via STUB1-Mediated Ubiquitination and Degradation of DLX2.
Premature termination codons (PTCs) in the MECP2 gene are a major cause of Rett syndrome, resulting in truncated proteins and loss of function. Pharmacological induction of translational readthrough (TR) can restore full-length protein, but clinical translation is hindered by the limited efficiency and toxicity of current inducers. Here, we investigated whether targeted degradation of the eukaryotic Release Factor 3a by the small molecules CC-885 or CC-90009 enhances TR at MECP2 PTCs in HeLa cells. Using a dual-fluorescence reporter assay, we found that neither degrader alone significantly increased TR efficiency. However, cotreatment with the TR inducer G418 produced a synergistic effect, resulting in increased TR compared to G418 alone. Although gentamicin, a less toxic TR inducer, led to only weak TR induction on its own, combination with CC-885 resulted in TR levels similar to G418. Combined CC-885 and G418 treatment enabled recovery of full-length MeCP2 protein as well as proper nuclear localization, consistent with functional recovery of the nuclear localization signal. These findings establish eRF3a degradation as a potential strategy to enhance TR and suggest that the combination of aminoglycosides with release factor degraders could provide a less toxic yet effective therapeutic option for PTC-associated disorders. • In combination with aminoglycosides, eRF3 degrader CC-885 enhances translational readthrough, demonstrating its role as a potentiator. • eRF3 degradation alone is insufficient to trigger translational readthrough. • Translational readthrough efficiency is strongly dependent on stop codon and context identity. • Co-treatment with CC-885 and aminoglycosides allows reduction of aminoglycoside dose to achieve relevant readthrough efficiencies. • Co-treatment restores full-length MeCP2 protein expression and promotes nuclear localization of the recovered protein.
Colorectal cancer (CRC) cells undergo significant alterations in glucose and glutamine metabolism to support rapid growth and migration. However, the molecular mechanisms underlying these metabolic changes remain incompletely understood. Although NUAK1 and NUAK2, members of the NUAK kinase family have been implicated in CRC tumorigenesis, their specific roles in metabolic reprogramming that drives CRC progression and metastasis have not been elucidated. In this study, we demonstrate that NUAK1 and NUAK2 are overexpressed in human CRC tissues and that their expression is associated with increased tumor metastasis and poorer patient survival. NUAK1/2 promotes CRC cell proliferation and migration, whereas their depletion markedly reduces cell growth and migratory capacity. Furthermore, knockout of NUAK1/2 disrupts key metabolic pathways, including aerobic glycolysis, pentose phosphate pathway (PPP), and glutamine metabolism. Mechanistically, NUAK1/2 facilitates mTOR-driven metabolic reprogramming and promotes CRC growth and migration by suppressing AMPK activity. Depletion of NUAK1/2 impairs metabolic function, cellular growth, and migration potential in CRC cells, effects that are further enhanced by pharmacological activation of AMPK with AICAR and inhibition of mTOR using Rapamycin. In conclusion, these findings identify NUAK1/2 as critical regulators of CRC progression and migration through AMPK/mTOR-mediated metabolic reprogramming, highlighting their potential as therapeutic targets in colorectal cancer.
