Title: Intervertebral disc and endplate cells response to IL-1β inflammatory cell priming and identification of molecular targets of tissue degeneration

Authors: P De Luca, L de Girolamo, D Kouroupis, M Castagnetta, C Perucca Orfei, D Coviello, S Coco, D Correa, M Brayda-Bruno, A Colombini

Address: Istituto Ortopedico Galeazzi, Orthopaedic Biotechnology Lab, Via R. Galeazzi 4, 20161, Milan, Italy

E-mail: alessandra.colombini at grupposandonato.it

Abstract: Inflammation represents an important factor leading to metabolic imbalance within the intervertebral disc (IVD), conducive to degenerative changes. Therefore, a thorough knowledge of the IVD and endplate (EP) cell behaviour in such pathological environments is essential when designing regenerative therapeutic strategies. The present study aimed at assessing the molecular response of the IVD constitutive nucleus pulposus (NPCs)-, annulus fibrosus (AFCs)- and endplate (EPCs)-derived cells to interleukin (IL)-1β treatment, through large-scale, high-throughput microarray and protein analysis, identifying the differentially expressed genes and released proteins. Overall, the inflammatory stimulus downregulated stemness genes while upregulating pro-inflammatory, pro-angiogenic and catabolic genes, including matrix metalloproteases, which were not balanced by a concomitant upregulation of their inhibitors. Upregulation of anti-inflammatory and anabolic tumour necrosis factor inducible gene 6 protein (TNFAIP6), of IL-1 receptor antagonist (IL-1Ra) (at gene and protein levels) and of trophic insulin-like growth factor 1 (IGF1) was also observed in all cell types; IGF1 particularly in AFCs. An overall inhibitory effect of tumour necrosis factor alpha (TNFα) signal was observed in all cell types; however, EPCs showed the strongest anti-inflammatory behaviour. AFCs and EPCs shared the ability to limit the activation of the signalling mediated by specific chemokines. AFCs showed a slightly senescent attitude, with a downregulation of genes related to DNA repair or pro-mitosis.
Results allowed for the identification of specific molecular targets in IVD and EP cells that respond to an inflammatory environment. Such targets can be either silenced (when pathological targets) or stimulated to counteract the inflammation.

Key Words: Intervertebral disc cells, endplate cells, interleukin 1 beta, gene array, protein array, inflammation markers.

Publication date: June 2nd 2020

Article download: Pages 227-248 (PDF file)
DOI: 10.22203/eCM.v039a15

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