bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2020.05.14.095588

Ectopic bone formation and systemic bone loss in a transmembrane TNF-driven model of human spondyloarthritis

Christodoulou-Vafeiadou, E.·Geka, C.·Ntari, L.·Kranidioti, K.·Argyropoulou, E.·Meier, F.·Armaka, M.·Mourouzis, I.·Pantos, C.·Rouchota, M.·Loudos, G.·Denis, M. C.·Karagianni, N.·Kollias, G.
View original source ↗Export metadata ↓

Abstract

Background The transmembrane-TNF transgenic mouse, TgA86, has been shown to develop spontaneously peripheral arthritis with signs of axial involvement. To assess similarity to human spondyloarthritis we performed detailed characterization of the axial, peripheral and comorbid pathologies of this model.Methods TgA86 bone pathologies were assessed at different ages using CT imaging of the spine, tail vertebrae and hind limbs and characterized in detail by histopathological and immunohistochemical analysis. Cardiac function was examined by echocardiography and electrocardiography and bone structural parameters by µCT analysis. The response of TgA86 mice to either early or late anti-TNF treatment was evaluated clinically, histopathologically and by µCT analysis.Results TgA86 mice developed with 100% penetrance spontaneous axial and peripheral pathology which progressed with time and manifested as reduced body weight and body length, kyphosis, tail bendings as well as swollen and distorted hind joints. Whole body CT analysis at advanced ages revealed bone erosions of sacral and caudal vertebrae as well as of sacroiliac joints and hind limps, and also, new ectopic bone formation and eventually vertebral fusion. The pathology of these mice highly resembled that of SpA patients, as it evolved through an early inflammatory phase, evident as enthesitis and synovitis in the affected joints, characterized by mesenchymal cell accumulation and neutrophilic infiltration. Subsequently, regression of inflammation was accompanied by ectopic bone formation, leading to ankylosis. In addition, both systemic bone loss and comorbid heart valve pathology were evident. Importantly, early anti-TNF treatment, similar to clinical treatment protocols, significantly reduced the inflammatory phase of both the axial and peripheral pathology of TgA86 mice.Conclusions The TgA86 mice develop a spontaneous peripheral and axial biphasic pathology accompanied by comorbid heart valvular dysfunction and osteoporosis, overall faithfully reproducing the progression of pathognomonic features of human spondyloarthritis. Therefore, the TgA86 mouse represents a valuable model for deciphering the pathogenic mechanisms of spondyloarthritis and for assessing the efficacy of human therapeutics targeting different phases of the disease.Competing Interest StatementProf. George Kollias participates in the BoD of Biomedcode; Dr. Florian Meier has received grants from Pfizer. All other authors declare no competing interests.List of abbreviationsASAnkylosing SpondylitisCTComputed TomographyCVDCardiovascular DiseaseEDTAEthylenediaminetetraacetic acidH&EHematoxylin&EosinIBDInflammatory Bowel DiseaseMRIMagnetic Resonance ImagingOPOsteoporosisOPNOsteopontinPsAPsoriatic arthritisRARheumatoid ArthritisReAReactive arthritiss/oSafranin/OSpASpondyloarthritisTgtransgenictmTNFtransmembrane mouseTNF TNF-αTumor Necrosis Factor αTRAPTartrate-resistant acid phosphataseUTRUntranslated RegionwtWild TypeµCTmicro CTView Full Text

Source connections

Explore related subjects

pathologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Christodoulou-Vafeiadou, E., Geka, C., Ntari, L., Kranidioti, K., Argyropoulou, E., Meier, F., Armaka, M., Mourouzis, I., Pantos, C., Rouchota, M., Loudos, G., Denis, M. C., Karagianni, N., Kollias, G.. 2020-05-16. Ectopic bone formation and systemic bone loss in a transmembrane TNF-driven model of human spondyloarthritis. https://doi.org/10.1101/2020.05.14.095588

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Midlife nonlinearities across scale in Biondi body amyloid formation in the human choroid plexus

Human choroid plexus epithelial cells (CPECs), which produce cerebrospinal fluid and form the blood-cerebrospinal fluid barrier, accumulate discrete intracellular amyloid inclusions called Biondi bodies (BBs). Using systematic manual and machine learning approaches on the choroid plexus glomus, we determined the percentages of CPECs containing thioflavin S-stained BBs as well as BB load and spatial distributions in whole slide images from 77 cases across the human lifespan. On average, BB prevalence was near zero until age 40, rose steeply in the 5th and 6th decades, and exceeded 50% after age 70. As prevalence plateaued, BB load continued to rise with age. Accelerated BB accumulation was seen in two cases of diabetic ketoacidosis, including a 16-year-old, while an 85-year-old with the relatively rare APOE2/E2 genotype had fewer BBs than expected. BB prevalence in the choroid plexus glomus was not associated with Alzheimer's disease, but was lower in females than males. Notably, spatial clustering of BBs was universal across cases while nearest-neighbor analyses suggested cell-to-cell, prion-like BB spread that can account for the nonlinearities seen at tissue and population scales. The abrupt, nonlinear BB accumulation during midlife coincides with or precedes other common aging-associated neuropathologies of the human brain, consistent with broad BB and choroid plexus contributions to brain aging and disease.

pathology↗
bioRxiv2026

Elevated precontractile calcium set point is sustained by limited PMCA1 export in dystrophic muscle

Duchenne muscular dystrophy is caused by loss of dystrophin and marked by elevated muscle calcium, usually attributed to contraction-induced membrane damage. Whether calcium rises before muscle can contract, and what sustains it, is unresolved. In Caenorhabditis elegans embryos and patient-derived human myoblasts, dystrophic muscle carries an elevated resting calcium set point before contraction is possible. Embryonic calcium is elevated 400 minutes after fertilization, before movement is detectable or the neuromuscular junction forms. Silencing the plasma membrane calcium pump gene mca-1 raises calcium in wild-type but not dystrophic animals, whereas silencing its paralogue raises it in both: the limitation is specific to that export route. Dystrophic human myoblasts have less pump; pump inhibition or silencing increases calcium preferentially in healthy cells, and raising pump expression lowers calcium most in dystrophic cells. Constrained calcium export is an early, continuing determinant of the dystrophic set point.

pathology↗
bioRxiv2026

Systematic comparison of gliflozins identifies a selective anti-calcifying effect of canagliflozin beyond canonical SGLT2 inhibition

Background: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) provide important cardiorenal benefits in chronic kidney disease (CKD), but their effects on vascular calcification remain conflicting. Whether potential anti-calcifying effects are shared across gliflozins or involve mechanisms beyond canonical SGLT2 inhibition is unknown. Methods: We systematically compared canagliflozin, dapagliflozin and empagliflozin in a high-phosphate diet-induced mouse model of vascular calcification and complementary ex vivo and in vitro models, including rodent and human vascular tissues and vascular smooth muscle cells (VSMCs). Aortic transcriptional response was investigated by RNA sequencing. VSMC calcification, proliferation, migration, viability, glucose uptake and bioenergetics were investigated using complementary cellular assays, including OsteoSense staining, Annexin V/propidium iodide staining, radiolabeled 2-deoxyglucose uptake and Seahorse ATP rate analysis. SGLT2/1 expression was examined by RT-qPCR, Western blotting and immunofluorescence. We also evaluated sotagliflozin, a dual SGLT1/2 inhibitor, and mizagliflozin, a selective SGLT1 inhibitor. Results: Among the three gliflozins, only canagliflozin significantly reduced aortic calcification in vivo. Its anti-calcifying effect was also observed in rodent aortic rings, human vascular explants, cultured VSMCs and aortic rings from diabetic db/db mice. Aortic RNA-seq revealed that canagliflozin partially reversed HPD-induced transcriptional alterations, including changes in pro-calcific signaling and cellular metabolism, while some endothelial and inflammatory responses were shared among gliflozins. In mouse VSMCs, canagliflozin reduced calcification across all tested concentrations, dose-dependently decreased osteogenic marker expression, and reduced proliferation and migration. Increased apoptotic and damaged cell fractions were observed at higher concentrations, but not at lower concentrations. Canagliflozin also reduced glucose uptake and mitochondrial ATP production, without significantly affecting glycolytic ATP production. Neither dapagliflozin nor empagliflozin reproduced these cellular and metabolic effects at any of the concentrations tested. SGLT2 and SGLT1 expression was low or undetectable in vascular tissues and cells, and neither sotagliflozin nor mizagliflozin reproduced the anti-calcifying effect of canagliflozin in vivo or in vitro. Conclusions: Canagliflozin exhibits a selective anti-calcifying profile among the gliflozins tested, associated with changes in VSMC responses and cellular metabolism. These findings suggest that its vascular protective effects may involve mechanisms beyond canonical SGLT2 inhibition.

pathology↗