Osteocyte-specific gasdermin D deletion accelerates osteoarthritis via promoting subchondral inflammation and remodeling

Abstract

Subchondral bone remodeling in the early stages of osteoarthritis (OA) is characterized by elevated bone turnover and is closely associated with osteocyte function within the subchondral bone. However, beyond the canonical role of gasdermin D (GSDMD) in mediating pyroptosis in immune cells, its function in osteocytes remains poorly understood. Accordingly, this study aimed to determine whether osteocyte-derived GSDMD regulates subchondral bone homeostasis or contributes to pathological remodeling during osteoarthritis progression. GSDMD expression was evident in osteocytes within the subchondral bone in both clinical and experimental models of OA, as well as in osteocytes co-cultured with stimulated chondrocytes, suggesting a potential role for osteocyte-derived GSDMD in the bone microenvironment. Remarkably, specific deletion of Gsdmd in osteocytes led to increased bone remodeling, which was accompanied by cartilage degeneration in an OA model, as well as bone loss in an osteoporosis model. Mechanistically, Gsdmd-deficient osteocytes displayed enhanced activation of CARD9/NF-κB signaling under inflammatory stimulation, leading to increased production of inflammatory mediators and osteoclastogenic factors that disrupted osteoblast-osteoclast coupling. These changes induced high-turnover subchondral bone remodeling, altered joint mechanical properties, and accelerated cartilage degeneration. Collectively, our findings identify osteocyte-derived GSDMD as an important regulator of subchondral bone remodeling and suggest that loss of this regulatory mechanism exacerbates OA progression. These results further indicate that therapeutic strategies targeting GSDMD should be approached with caution due to potential effects on bone remodeling and inflammatory signaling.

References

[1] Global Burden of Disease Collaborative Network. Global Burden of Disease Study 2019 (GBD 2019) Results. (Institute for Health Metrics and Evaluation (IHME), 2019).

[2] Leifer VP, Katz JN, Losina E. The burden of OA-health services and economics. Osteoarthr. Cartil., 2022, 30: 10-16

[3] Terkawi, M. A. et al. Low-Grade inflammation in the pathogenesis of osteoarthritis: cellular and molecular mechanisms and strategies for future therapeutic intervention. Biomedicines10, 1109 (2022).

[4] Hu Y, Chen X, Wang S, Jing Y, Su J. Subchondral bone microenvironment in osteoarthritis and pain. Bone Res., 2021, 9: 20

[5] Burr DB, Gallant MA. Bone remodelling in osteoarthritis. Nat. Rev. Rheumatol., 2012, 8: 665-673

[6] Maas O, Joseph GB, Sommer G, Wild D, Kretzschmar M. Association between cartilage degeneration and subchondral bone remodeling in patients with knee osteoarthritis comparing MRI and (99m)Tc-DPD-SPECT/CT. Osteoarthr. Cartil., 2015, 23: 1713-1720

[7] Hu W, Chen Y, Dou C, Dong S. Microenvironment in subchondral bone: predominant regulator for the treatment of osteoarthritis. Ann. Rheum. Dis., 2021, 80: 413-422

[8] Bonewald LF. The amazing osteocyte. J. Bone Miner. Res., 2011, 26: 229-238

[9] Ebata T, et al.. Noncanonical pyroptosis triggered by macrophage-derived extracellular vesicles in chondrocytes leading to cartilage catabolism in osteoarthritis. Arthritis Rheumatol., 2023, 75: 1358-1369

[10] Weindel CG, Ellzey LM, Martinez EL, Watson RO, Patrick KL. Gasdermins gone wild: new roles for GSDMs in regulating cellular homeostasis. Trends Cell Biol., 2023, 33: 773-787

[11] Liu Y, et al.. Pyroptosis in health and disease: mechanisms, regulation and clinical perspective. Signal Transduct. Target. Ther., 2024, 9: 245

[12] Terkawi, M. A. et al. Interplay between inflammation and pathological bone resorption: insights into recent mechanisms and pathways in related diseases for future perspectives. Int. J. Mol. Sci.23, 1786 (2022).

[13] Devant P, et al.. Gasdermin D pore-forming activity is redox-sensitive. Cell Rep., 2023, 42 ArticleID: 112008

[14] Qu Y, et al.. Gasdermin D mediates endoplasmic reticulum stress via FAM134B to regulate cardiomyocyte autophagy and apoptosis in doxorubicin-induced cardiotoxicity. Cell Death Dis., 2022, 13 ArticleID: 901

[15] Li M, et al.. Gasdermin D maintains bone mass by rewiring the endo-lysosomal pathway of osteoclastic bone resorption. Dev. Cell, 2022, 57: 2365-2380.e2368

[16] Chi Z, et al.. Gasdermin D-mediated metabolic crosstalk promotes tissue repair. Nature, 2024, 634: 1168-1177

[17] Zhang J, et al.. Epithelial Gasdermin D shapes the host-microbial interface by driving mucus layer formation. Sci. Immunol., 2022, 7 ArticleID: eabk2092

[18] Chen Y, et al.. Gasdermin D drives the nonexosomal secretion of galectin-3, an insulin signal antagonist. J. Immunol., 2019, 203: 2712-2723

[19] Chen L, Kadoya K, Endo T, Iwasaki N, Terkawi MA. Efferocytosis at the frontline of homeostasis: shaping the bone microenvironment and therapeutic implications in related diseases. Cytokine Growth Factor Rev., 2025, 83: 85-98

[20] Azari F, Hemmatian H, Banerjee A, van Lenthe GH. Subchondral bone osteocyte lacunae morphology in end-stage osteoarthritis of the human tibial plateau. Calcif. Tissue Int., 2024, 115: 78-84

[21] Yang J, et al.. Targeting cell death: pyroptosis, ferroptosis, apoptosis and necroptosis in osteoarthritis. Front. Cell Dev. Biol., 2021, 9 ArticleID: 789948

[22] Yang T, et al.. Gasdermin D deficiency attenuates arthritis induced by traumatic injury but not autoantibody-assembled immune complexes. Arthritis Res Ther., 2021, 23: 286

[23] Fritz JH, Ferrero RL, Philpott DJ, Girardin SE. Nod-like proteins in immunity, inflammation and disease. Nat. Immunol., 2006, 7: 1250-1257

[24] Carneiro LA, Magalhaes JG, Tattoli I, Philpott DJ, Travassos LH. Nod-like proteins in inflammation and disease. J. Pathol., 2008, 214: 136-148

[25] Zhernakova A, et al.. Genetic analysis of innate immunity in Crohn’s disease and ulcerative colitis identifies two susceptibility loci harboring CARD9 and IL18RAP. Am. J. Hum. Genet., 2008, 82: 1202-1210

[26] Colonna M. All roads lead to CARD9. Nat. Immunol., 2007, 8: 554-555

[27] Oliveira Silva M, Gregory JL, Ansari N, Stok KS. Molecular signaling interactions and transport at the osteochondral interface: a review. Front. Cell Dev. Biol., 2020, 8: 750

[28] Suri S, et al.. Neurovascular invasion at the osteochondral junction and in osteophytes in osteoarthritis. Ann. Rheum. Dis., 2007, 66: 1423-1428

[29] Findlay DM, Kuliwaba JS. Bone-cartilage crosstalk: a conversation for understanding osteoarthritis. Bone Res., 2016, 4 ArticleID: 16028

[30] Wang, Y. et al. Radiation induces primary osteocyte senescence phenotype and affects osteoclastogenesis. Int. J. Mol. Med.47, 76 (2021).

[31] Fujii T, et al.. Gasdermin D (Gsdmd) is dispensable for mouse intestinal epithelium development. Genesis, 2008, 46: 418-423

[32] Lu Y, et al.. DMP1-targeted Cre expression in odontoblasts and osteocytes. J. Dent. Res., 2007, 86: 320-325

[33] Krenn V, et al.. Synovitis score: discrimination between chronic low-grade and high-grade synovitis. Histopathology, 2006, 49: 358-364

[34] Kamekura S, et al.. Osteoarthritis development in novel experimental mouse models induced by knee joint instability. Osteoarthr. Cartil., 2005, 13: 632-641

[35] Nishida, Y. et al. Dynamic transcriptome analysis of osteal macrophages identifies a distinct subset with senescence features in experimental osteoporosis. JCI Insight9, e182418 (2024).

[36] Yokota S, et al.. Cardiotrophin Like Cytokine Factor 1 (CLCF1) alleviates bone loss in osteoporosis mouse models by suppressing osteoclast differentiation through activating interferon signaling and repressing the nuclear factor-κB signaling pathway. Bone, 2021, 153 ArticleID: 116140

[37] Hornung V, et al.. Silica crystals and aluminum salts activate the NALP3 inflammasome through phagosomal destabilization. Nat. Immunol., 2008, 9: 847-856

[38] Franchi L, Eigenbrod T, Muñoz-Planillo R, Nuñez G. The inflammasome: a caspase-1-activation platform that regulates immune responses and disease pathogenesis. Nat. Immunol., 2009, 10: 241-247

[39] Mortazavi A, Williams BA, McCue K, Schaeffer L, Wold B. Mapping and quantifying mammalian transcriptomes by RNA-Seq. Nat. Methods, 2008, 5: 621-628

[40] Tang, D. et al. SRplot: a free online platform for data visualization and graphing. PLoS One18, e0294236 (2023).

[41] Hu Y, et al.. Single-cell RNA-sequencing analysis reveals the molecular mechanism of subchondral bone cell heterogeneity in the development of osteoarthritis. RMD Open, 2022, 8: e002314

Funding

Japan Agency for Medical Research and Development (AMED)(PJ4221KB01)

Japan Science Society(21K16673)

RIGHTS & PERMISSIONS

The Author(s)