How Cellular Senescence Drives Bone, Muscle, and Joint Disease — and How to Stop It
A comprehensive 2026 review maps the cellular senescence mechanisms behind seven major musculoskeletal diseases and evaluates emerging senolytic therapies.
Résumé
This 2026 review in Theranostics systematically examines how cellular senescence — the irreversible growth arrest of stressed cells — contributes to seven musculoskeletal diseases: skeletal muscle injury and regeneration, sarcopenia, osteoporosis, fracture, osteonecrosis of the femoral head (ONFH), osteoarthritis (OA), and intervertebral disc degeneration (IDD). The authors detail how senescent cells accumulate in poorly vascularized, long-lived tissue compartments like bone, cartilage, and muscle, where immune clearance is limited. They highlight the senescence-associated secretory phenotype (SASP) as a central driver of chronic inflammation and tissue degeneration, while also acknowledging beneficial roles in wound healing and fracture repair. Senolytic and senomorphic therapeutic strategies are critically evaluated across disease contexts.
Résumé détaillé
Cellular senescence — a state of permanent cell cycle arrest triggered by DNA damage, oxidative stress, or oncogenic signals — has emerged as a key driver of age-related musculoskeletal degeneration. This comprehensive review by Li, Qi, Zhang, and colleagues, published in Theranostics (2026), synthesizes current evidence across seven distinct musculoskeletal conditions, offering both mechanistic clarity and therapeutic direction.
The review opens by addressing a fundamental diagnostic challenge: no single biomarker reliably identifies senescent cells. The authors advocate for multi-marker approaches combining p16Ink4a and p21Cip1 expression, senescence-associated β-galactosidase (SA-β-gal) activity, DNA damage markers (γH2AX), and SASP profiling. Importantly, they highlight tissue-specific caveats — for example, synovial macrophages and osteoclasts have high endogenous β-galactosidase activity, making SA-β-gal unreliable in isolation for these cell types. The SenMayo 125-gene senescence signature is highlighted as a promising tool for single-cell resolution identification of senescent cells in bone marrow.
In skeletal muscle, senescent cells — including muscle stem cells (MuSCs/satellite cells), fibro/adipogenic progenitors (FAPs), and immune cells — play a dual role. Transient senescence supports muscle regeneration after acute injury by coordinating inflammatory clearance and progenitor activation, while chronic senescent cell accumulation in sarcopenia impairs MuSC function, promotes fibrosis, and drives progressive muscle atrophy. The SASP from senescent FAPs and macrophages is particularly implicated in this pathological shift.
In bone, the review delineates how senescent osteocytes, osteoblasts, and bone marrow stromal cells contribute to osteoporosis through RANKL upregulation, reduced osteoblastogenesis, and marrow adiposity. Notably, p21Cip1-positive (rather than p16Ink4a-positive) senescent cells were shown in one model to drive radiation-induced bone loss — underscoring cell-type and context-specific senescence programs. In fracture healing, transient senescence at injury sites plays a beneficial role in callus formation and angiogenesis, while persistent senescence impairs repair. For ONFH, osteocyte senescence under ischemic and glucocorticoid-induced stress is highlighted as a central pathological mechanism.
In cartilaginous tissues, chondrocyte senescence drives OA through SASP-mediated matrix degradation (MMP upregulation, aggrecan loss) and suppression of anabolic repair signals. Nucleus pulposus cell senescence is similarly central to IDD, with oxidative stress and mechanical overload accelerating the senescent transition. The review critically evaluates senolytic agents (e.g., dasatinib + quercetin, navitoclax, ABT-263) and senomorphics (e.g., rapamycin, JAK inhibitors) in these disease contexts, noting that disease-specific senescent cell types, SASP compositions, and tissue microenvironments necessitate tailored therapeutic strategies rather than a one-size-fits-all approach. The authors call for integration of spatial transcriptomics, single-cell multi-omics, and improved in vivo reporter models (e.g., Glb1-2A-mCherry mice) to advance both diagnosis and targeted therapy.
Principales conclusions
- No single biomarker reliably identifies senescent cells; multi-marker panels including p16Ink4a, p21Cip1, SA-β-gal, and SASP profiling are required.
- p21Cip1-positive, not p16Ink4a-positive, senescent cells primarily drive radiation-induced bone loss and marrow adiposity in mouse models.
- Transient senescence supports muscle regeneration and fracture healing, while chronic accumulation drives sarcopenia, OA, and IDD.
- SASP from senescent chondrocytes and nucleus pulposus cells drives matrix degradation and inflammation in OA and intervertebral disc degeneration.
- Senolytics (dasatinib+quercetin, navitoclax) and senomorphics (rapamycin, JAK inhibitors) show disease-specific efficacy requiring tissue-tailored application.
Méthodologie
This is a narrative review article synthesizing published experimental, preclinical, and clinical literature on cellular senescence across seven musculoskeletal disease categories. The authors integrate data from mouse genetic models, human biopsy studies, single-cell RNA sequencing datasets, and pharmacological intervention studies. No original experimental data were generated.
Limites de l'étude
As a narrative rather than systematic review, selection bias in included studies cannot be excluded. Most mechanistic evidence derives from rodent models, and translation to human musculoskeletal disease remains incompletely validated. The optimal combination and thresholds of senescence biomarkers for clinical diagnosis have not yet been standardized.
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