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Updated: May 28, 2026
Software-Assisted Quantitative Measurement of Osteoarthritic Subchondral Bone Thickness
Published on: March 18, 2022
Enolase 2-mediated lactylation-dependent disruption of the GNL3-MDM2-p53 axis in age-related osteoarthritis
Feng Hua1, Jiangyu Nan1, Rong Wu1
1Department of Orthopedics, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
Background:
Age-related osteoarthritis (OA) involves metabolic dysregulation and chondrocyte senescence. This study examined the nonmetabolic role of enolase 2 (ENO2) in OA pathogenesis and its therapeutic potential.
Methods:
Human aged and OA cartilage (n = 3 per group) underwent 18F-FDG positron emission tomography (PET)-computed tomography (CT) imaging, proteomic profiling, and immunohistochemistry. In vitro chondrocyte senescence models were generated by inducing doxorubicin-induced stress and serial passaging. Protein-protein interactions (ENO2-GNL3-MDM2) were validated by co-immunoprecipitation (IP), GST pull-down, and site-directed mutagenesis (E4A-ENO2 and K5R-GNL3 mutants). Lactylation was assessed using lactylomics and immunoprecipitation. The therapeutic effect of the ENO2-specific inhibitor POMHEX was evaluated in C57BL/6 J mice (n = 6 per group) via intra-articular injection for 16 weeks. Outcomes included histology, micro-CT, pain behavior, and gait analysis.
Results:
Proteomics revealed ENO2 upregulation in aged human cartilage. In vitro, ENO2 overexpression promoted extracellular matrix catabolism, senescence, and glycolysis, whereas ENO2 knockdown attenuated these processes. Mediated by its Glu-4 residue, nuclear ENO2 bound GNL3 lactylated at Lys-5. This interaction displaced MDM2 from GNL3, resulting in MDM2 destabilization, impaired ubiquitination, p53 accumulation, and persistent senescence. Moreover, p53 transcriptionally activated ENO2, establishing a pathological positive feedback loop. Pharmacological inhibition of ENO2 with POMHEX disrupted ENO2-GNL3 binding, restored p53 degradation, reduced senescence markers in vitro, and mitigated cartilage degradation, subchondral bone sclerosis, and pain in aged mice.
Conclusions:
ENO2 promotes OA progression through a lactate-dependent, lactylation-mediated disruption of the GNL3-MDM2-p53 axis, leading to a senescent feedback loop. Targeting ENO2 may represent a novel disease-modifying therapeutic approach for age-related OA.
Insights
Enolase 2 (ENO2) drives osteoarthritis (OA) by disrupting the GNL3-MDM2-p53 pathway, causing chondrocyte senescence. Inhibiting ENO2 offers a potential therapeutic strategy for age-related OA.
Area of Science:
- Biochemistry
- Cell Biology
- Orthopedics
Background:
- Age-related osteoarthritis (OA) is characterized by metabolic dysregulation and chondrocyte senescence.
- The nonmetabolic role of enolase 2 (ENO2) in OA pathogenesis requires investigation.
Purpose of the Study:
- To examine the role of enolase 2 (ENO2) in osteoarthritis (OA) pathogenesis.
- To evaluate the therapeutic potential of targeting ENO2 in age-related OA.
Main Methods:
- Proteomic profiling and immunohistochemistry on human aged and OA cartilage.
- In vitro chondrocyte senescence models and validation of protein-protein interactions (ENO2-GNL3-MDM2).
- Assessment of lactylation and therapeutic evaluation of the ENO2 inhibitor POMHEX in aged mice.
Main Results:
- ENO2 was upregulated in aged human cartilage and promoted OA hallmarks in vitro.
- ENO2-GNL3 interaction, mediated by lactylation, led to p53 accumulation and senescence.
- ENO2 inhibition with POMHEX reduced OA pathology and pain in mice.
Conclusions:
- ENO2 promotes OA via a lactylation-mediated disruption of the GNL3-MDM2-p53 axis, creating a senescence feedback loop.
- Targeting ENO2 presents a novel disease-modifying therapeutic approach for age-related OA.
