Cytosolic phospholipase A2 as a therapeutic target for degenerative joint diseases

Abstract

Osteoarthritis (OA) and intervertebral disc degeneration (IVDD) are degenerative musculoskeletal disorders characterized by degeneration of cartilaginous tissues and inflammation. While inflammation is implicated in the pathogenesis of OA and IVDD, and cytosolic phospholipase A2 (cPLA2) is a key mediator of inflammation, direct evidence linking cPLA2 to chondrocyte homeostasis and cartilage degeneration is lacking. This study aims to investigate the role of cPLA2 in chondrocytes and its contribution to the development of cartilage degenerative conditions such as OA and IVDD. Here, single-cell RNA sequencing was used to examine cPLA2 expression in chondrocytes. To explore its importance in chondrocytes and OA/IVDD, various cell-based assays and genetically modified mouse models with age-related and surgically induced OA/IVDD were employed. Furthermore, the therapeutic potential of fexofenadine, an over-the-counter drug recently identified as a cPLA2 inhibitor, was explored in these models. cPLA2 is predominantly expressed in prehypertrophic chondrocytes, characterized by elevated levels of cartilage degeneration markers and senescence-related genes. Genetic deletion and pharmacological inhibition of cPLA2 reduced inflammation induced catabolic activity and senescence in chondrocytes, as well as cartilage degeneration in various OA and IVDD models. This study identifies cPLA2 as a pivotal driver of cartilage degeneration and senescence in OA and IVDD, highlighting its potential as a dual-action therapeutic target that suppresses both inflammation and senescence to preserve cartilage integrity. These findings position cPLA2 as a promising candidate for developing disease-modifying therapies for cartilage degenerative conditions such as OA and IVDD.

References

[1] Glyn-Jones S. et al.. Osteoarthritis. Lancet, 2015, 386: 376-387.

[2] Fu W. et al.. Na(v)1.7 as a chondrocyte regulator and therapeutic target for osteoarthritis. Nature, 2024, 625: 557-565.

[3] Tang S. et al.. Single-cell atlas of human infrapatellar fat pad and synovium implicates APOE signaling in osteoarthritis pathology. Sci. Transl. Med., 2024, 16. eadf4590

[4] Loeser RF, Goldring SR, Scanzello CR, Goldring MB. Osteoarthritis: a disease of the joint as an organ. Arthritis Rheum., 2012, 64: 1697-1707.

[5] Wang C. et al.. Deletion of Glut1 in early postnatal cartilage reprograms chondrocytes toward enhanced glutamine oxidation. Bone Res., 2021, 9: 38.

[6] Zuscik MJ, Hilton MJ, Zhang X, Chen D, O’Keefe RJ. Regulation of chondrogenesis and chondrocyte differentiation by stress. J. Clin. Invest., 2008, 118: 429-438.

[7] Sanchez-Lopez E, Coras R, Torres A, Lane NE, Guma M. Synovial inflammation in osteoarthritis progression. Nat. Rev. Rheumatol., 2022, 18: 258-275.

[8] Loeser RF, Collins JA, Diekman BO. Ageing and the pathogenesis of osteoarthritis. Nat. Rev. Rheumatol., 2016, 12: 412-420.

[9] He C-P. et al.. The role of AGEs in pathogenesis of cartilage destruction in osteoarthritis. Bone Jt. Res., 2022, 11: 292-300.

[10] Martel-Pelletier J. et al.. Osteoarthritis. Nat. Rev. Dis. Prim., 2016, 2. 16072

[11] Robinson WH. et al.. Low-grade inflammation as a key mediator of the pathogenesis of osteoarthritis. Nat. Rev. Rheumatol., 2016, 12: 580-592.

[12] Asai S. et al.. Tendon progenitor cells in injured tendons have strong chondrogenic potential: the CD105-negative subpopulation induces chondrogenic degeneration. Stem Cells, 2014, 32: 3266-3277.

[13] Wei X. et al.. A human organoid drug screen identifies α2-adrenergic receptor signaling as a therapeutic target for cartilage regeneration. Cell Stem Cell, 2024, 31: 1813-1830.e1818.

[14] Murphy MP. et al.. Articular cartilage regeneration by activated skeletal stem cells. Nat. Med., 2020, 26: 1583-1592.

[15] Zhang W. et al.. OARSI recommendations for the management of hip and knee osteoarthritis: part III: Changes in evidence following systematic cumulative update of research published through January 2009. Osteoarthr. Cartil., 2010, 18: 476-499.

[16] Antoinette AY. et al.. PTH treatment before cyclic joint loading improves cartilage health and attenuates load-induced osteoarthritis development in mice. Sci. Adv., 2024, 10. eadk8402

[17] Li C. et al.. Neural EGFL like 1 as a potential pro-chondrogenic, anti-inflammatory dual-functional disease-modifying osteoarthritis drug. Biomaterials, 2020, 226. 119541

[18] Cho Y. et al.. Disease-modifying therapeutic strategies in osteoarthritis: current status and future directions. Exp. Mol. Med., 2021, 53: 1689-1696.

[19] Zheng L, Lu Z, Xu G, Niu X, Zhao J. Dual-targeted disease-modifying therapies for osteoarthritis. Lancet, 2024, 403: 2591.

[20] Masuda S. et al.. Various secretory phospholipase A2 enzymes are expressed in rheumatoid arthritis and augment prostaglandin production in cultured synovial cells. Febs. j., 2005, 272: 655-672.

[21] Yedgar S, Cohen Y, Shoseyov D. Control of phospholipase A2 activities for the treatment of inflammatory conditions. Biochim Biophys. Acta, 2006, 1761: 1373-1382.

[22] Wei, Y. et al. Phospholipase A(2) inhibitor-loaded micellar nanoparticles attenuate inflammation and mitigate osteoarthritis progression. Sci. Adv.7, eabe6374 (2021).

[23] Thwin MM. et al.. Suppressive effect of secretory phospholipase A2 inhibitory peptide on interleukin-1beta-induced matrix metalloproteinase production in rheumatoid synovial fibroblasts, and its antiarthritic activity in hTNFtg mice. Arthritis Res. Ther., 2009, 11. R138

[24] Pruzanski W. et al.. Induction of release of secretory nonpancreatic phospholipase A2 from human articular chondrocytes. J. Rheumatol., 1995, 22: 2114-2119

[25] Zhao, X., Liu, R., Chen, Y., Hettinghouse, A. & Liu, C. Cytosolic Phospholipase A2 Is Required for Fexofenadine’s Therapeutic Effects against Inflammatory Bowel Disease in Mice. Int. J. Mol. Sci.22, 11155 (2021).

[26] Hasan S. et al.. Dietary pyruvate targets cytosolic phospholipase A2 to mitigate inflammation and obesity in mice. Protein Cell, 2024, 15: 661-685.

[27] Wang S. et al.. Calcium-dependent cytosolic phospholipase A(2) activation is implicated in neuroinflammation and oxidative stress associated with ApoE4. Mol. Neurodegener., 2022, 17: 42.

[28] Khan, S. A. & Ilies, M. A. The Phospholipase A2 Superfamily: Structure, Isozymes, Catalysis, Physiologic and Pathologic Roles. Int. J. Mol. Sci.24, 1353 (2023).

[29] Lin LL. et al.. cPLA2 is phosphorylated and activated by MAP kinase. Cell, 1993, 72: 269-278.

[30] Koundouros N. et al.. Metabolic Fingerprinting Links Oncogenic PIK3CA with Enhanced Arachidonic Acid-Derived Eicosanoids. Cell, 2020, 181: 1596-1611.e1527.

[31] Brash AR. Arachidonic acid as a bioactive molecule. J. Clin. Invest, 2001, 107: 1339-1345.

[32] Seo MJ, Oh DK. Prostaglandin synthases: Molecular characterization and involvement in prostaglandin biosynthesis. Prog. Lipid Res, 2017, 66: 50-68.

[33] Gonzalez-Perilli L, Prolo C, Alvarez MN. Arachidonic Acid and Nitroarachidonic: Effects on NADPH Oxidase Activity. Adv. Exp. Med Biol., 2019, 1127: 85-95.

[34] Ye Z. et al.. Arachidonic acid-regulated calcium signaling in T cells from patients with rheumatoid arthritis promotes synovial inflammation. Nat. Commun., 2021, 12. 907

[35] Liu R. et al.. Fexofenadine inhibits TNF signaling through targeting to cytosolic phospholipase A2 and is therapeutic against inflammatory arthritis. Ann. Rheum. Dis., 2019, 78: 1524-1535.

[36] Teixeira GQ, Riegger J, Goncalves RM, Risbud MV. Editorial: Intervertebral disc degeneration and osteoarthritis: mechanisms of disease and functional repair. Front Bioeng. Biotechnol., 2023, 11. 1252703

[37] van Rheenen W. et al.. Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology. Nat. Genet, 2021, 53: 1636-1648.

[38] Ji Q. et al.. Single-cell RNA-seq analysis reveals the progression of human osteoarthritis. Ann. Rheum. Dis., 2019, 78: 100-110.

[39] Knights AJ, Redding SJ, Maerz T. Inflammation in osteoarthritis: the latest progress and ongoing challenges. Curr. Opin. Rheumatol., 2023, 35: 128-134.

[40] López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. Hallmarks of aging: An expanding universe. Cell, 2023, 186: 243-278.

[41] Farooqui AA, Ong WY, Horrocks LA. Inhibitors of brain phospholipase A2 activity: their neuropharmacological effects and therapeutic importance for the treatment of neurologic disorders. Pharm. Rev., 2006, 58: 591-620.

[42] Fields AJ, Ballatori A, Liebenberg EC, Lotz JC. Contribution of the endplates to disc degeneration. Curr. Mol. Biol. Rep., 2018, 4: 151-160.

[43] Ling Z. et al.. Parathyroid hormone treatment partially reverses endplate remodeling and attenuates low back pain in animal models of spine degeneration. Sci. Transl. Med, 2023, 15. eadg8982

[44] Liu K. et al.. Fexofenadine Protects Against Intervertebral Disc Degeneration Through TNF Signaling. Front Cell Dev. Biol., 2021, 9. 687024

[45] Gan Y. et al.. Spatially defined single-cell transcriptional profiling characterizes diverse chondrocyte subtypes and nucleus pulposus progenitors in human intervertebral discs. Bone Res, 2021, 9: 37.

[46] Liu, S., Sun, Y., Dong, J. & Bian, Q. A Mouse Model of Lumbar Spine Instability. J. Vis. Exp. 23, e61722 (2021).

[47] Han B. et al.. A simple disc degeneration model induced by percutaneous needle puncture in the rat tail. Spine (Philos. Pa 1976), 2008, 33: 1925-1934.

[48] Wang F, Cai F, Shi R, Wang XH, Wu XT. Aging and age related stresses: a senescence mechanism of intervertebral disc degeneration. Osteoarthr. Cartil., 2016, 24: 398-408.

[49] Kodama J, Wilkinson KJ, Iwamoto M, Otsuru S, Enomoto-Iwamoto M. The role of hypertrophic chondrocytes in regulation of the cartilage-to-bone transition in fracture healing. Bone Rep., 2022, 17. 101616

[50] Zhan Q. et al.. The opposite effects of Antarctic krill oil and arachidonic acid-rich oil on bone resorption in ovariectomized mice. Food Funct., 2020, 11: 7048-7060.

[51] Miyaura C. et al.. An essential role of cytosolic phospholipase A2alpha in prostaglandin E2-mediated bone resorption associated with inflammation. J. Exp. Med., 2003, 197: 1303-1310.

[52] Coryell PR, Diekman BO, Loeser RF. Mechanisms and therapeutic implications of cellular senescence in osteoarthritis. Nat. Rev. Rheumatol., 2021, 17: 47-57.

[53] Liu Y, Zhang Z, Li T, Xu H, Zhang H. Senescence in osteoarthritis: from mechanism to potential treatment. Arthritis. Res. Ther., 2022, 24: 174.

[54] Bonventre JV. et al.. Reduced fertility and postischaemic brain injury in mice deficient in cytosolic phospholipase A2. Nature, 1997, 390: 622-625.

[55] Dennis EA, Cao J, Hsu YH, Magrioti V, Kokotos GPhospholipaseA. 2 enzymes: physical structure, biological function, disease implication, chemical inhibition, and therapeutic intervention. Chem. Rev., 2011, 111: 6130-6185.

[56] Leslie CC. Properties and regulation of cytosolic phospholipase A2. J. Biol. Chem., 1997, 272: 16709-16712.

[57] Abshirini M, Ilesanmi-Oyelere BL, Kruger MC. Potential modulatory mechanisms of action by long-chain polyunsaturated fatty acids on bone cell and chondrocyte metabolism. Prog. Lipid Res., 2021, 83. 101113

[58] Chen GY. et al.. Total Flavonoids of Rhizoma Drynariae Treat Osteoarthritis by Inhibiting Arachidonic Acid Metabolites Through AMPK/NFκB Pathway. J. Inflamm. Res., 2023, 16: 4123-4140.

[59] Finn AFJr., Kaplan AP, Fretwell R, Qu R, Long J. A double-blind, placebo-controlled trial of fexofenadine HCl in the treatment of chronic idiopathic urticaria. J. Allergy Clin. Immunol., 1999, 104: 1071-1078.

[60] Leurs R, Vischer HF, Wijtmans M, de Esch IJ. En route to new blockbuster anti-histamines: surveying the offspring of the expanding histamine receptor family. Trends Pharm. Sci., 2011, 32: 250-257.

[61] Phan H, Moeller ML, Nahata MC. Treatment of allergic rhinitis in infants and children: efficacy and safety of second-generation antihistamines and the leukotriene receptor antagonist montelukast. Drugs, 2009, 69: 2541-2576.

[62] Chen M. et al.. Inhibition of beta-catenin signaling causes defects in postnatal cartilage development. J. Cell Sci., 2008, 121: 1455-1465.

[63] Dong YF. et al.. Transforming growth factor-beta and Wnt signals regulate chondrocyte differentiation through Twist1 in a stage-specific manner. Mol. Endocrinol., 2007, 21: 2805-2820.

[64] Wang C, Shen J, Ying J, Xiao D, O’Keefe RJ. FoxO1 is a crucial mediator of TGF-β/TAK1 signaling and protects against osteoarthritis by maintaining articular cartilage homeostasis. Proc. Natl. Acad. Sci. USA, 2020, 117: 30488-30497.

[65] Glasson SS, Blanchet TJ, Morris EA. The surgical destabilization of the medial meniscus (DMM) model of osteoarthritis in the 129/SvEv mouse. Osteoarthr. Cartil., 2007, 15: 1061-1069.

[66] Fu W. et al.. 14-3-3 epsilon is an intracellular component of TNFR2 receptor complex and its activation protects against osteoarthritis. Ann. Rheum. Dis., 2021, 80: 1615-1627.

[67] Ran FA. et al.. Genome engineering using the CRISPR-Cas9 system. Nat. Protoc., 2013, 8: 2281-2308.

[68] Goldring MB. et al.. Interleukin-1 beta-modulated gene expression in immortalized human chondrocytes. J. Clin. Invest., 1994, 94: 2307-2316.

[69] Kuang, B. et al. Panaxatriol exerts anti-senescence effects and alleviates osteoarthritis and cartilage repair fibrosis by targeting UFL1. J. Adv. Res. (2024).

[70] Geng N. et al.. Targeting the senescence-related genes MAPK12 and FOS to alleviate osteoarthritis. J. Orthop. Transl., 2024, 47: 50-62

[71] Kang D. et al.. Regulation of senescence-associated secretory phenotypes in osteoarthritis by cytosolic UDP-GlcNAc retention and O-GlcNAcylation. Nat. Commun., 2025, 16. 1094

[72] Geng N. et al.. 10-hydroxy-2-decenoic acid prevents osteoarthritis by targeting aspartyl β hydroxylase and inhibiting chondrocyte senescence in male mice preclinically. Nat. Commun., 2024, 15. 7712

[73] Glasson SS, Chambers MG, Van Den Berg WB, Little CB. The OARSI histopathology initiative - recommendations for histological assessments of osteoarthritis in the mouse. Osteoarthr. Cartil., 2010, 18: S17-S23.

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

[75] Das Neves Borges P, Vincent TL, Marenzana M. Automated assessment of bone changes in cross-sectional micro-CT studies of murine experimental osteoarthritis. PLoS One, 2017, 12: e0174294.

[76] Little CB. et al.. Matrix metalloproteinase 13-deficient mice are resistant to osteoarthritic cartilage erosion but not chondrocyte hypertrophy or osteophyte development. Arthritis Rheum., 2009, 60: 3723-3733.

[77] Boos N. et al.. Classification of age-related changes in lumbar intervertebral discs: 2002 Volvo Award in basic science. Spine (Philos. Pa 1976), 2002, 27: 2631-2644.

[78] Masuda K. et al.. A novel rabbit model of mild, reproducible disc degeneration by an anulus needle puncture: correlation between the degree of disc injury and radiological and histological appearances of disc degeneration. Spine (Philos. Pa 1976), 2005, 30: 5-14.

[79] Ruan MZ, Patel RM, Dawson BC, Jiang MM, Lee BH. Pain, motor and gait assessment of murine osteoarthritis in a cruciate ligament transection model. Osteoarthr. Cartil., 2013, 21: 1355-1364.

RIGHTS & PERMISSIONS

The Author(s)