Interleukin-23 is constitutively expressed in the human annulus in vivo and in vitro, and is up-regulated in vitro by TNF-α

ERBB2-PTGS2 axis promotes intervertebral disc degeneration by regulating senescence of nucleus pulposus cells

Intervertebral disc degeneration (IDD) is considered one of the main causes of low back pain and lumbar disc herniation. Various studies have shown that disc cell senescence plays a critical role in this process. however, its role in IDD is yet unclear. In this study, we explored the role of senescence-related genes (SR-DEGs) and its underlying mechanism in IDD. A total of 1325 differentially expressed genes (DEGs) were identified using Gene Expression Omnibus (GEO) database GSE41883. 30 SR-DEGs were identified for further functional enrichment and pathway analysis, and two hub SR-DEGs (ERBB2 and PTGS2) were selected to construct transcription factor (TF)-gene interaction and TF-miRNA coregulatory networks, and 10 candidate drugs were screened for the treatment of IDD. Last but not least, in vitro experiments show that ERBB2 expression decreased and PTGS2 expression increased in human nucleus pulposus (NP) cell senescence model treated with TNF-α. After lentivirus-mediated overexpression of ERBB2, the expression of PTGS2 decreased and the senescence level of NP cells decreased. Overexpression of PTGS2 reversed the anti-senescence effects of ERBB2. The findings in this study suggested that ERBB2 overexpression further reduced NP cell senescence by inhibiting PTGS2 levels, which ultimately alleviated IDD. Taken together, our findings provide new insights into the roles of senescence-related genes in IDD and highlight a novel target of ERBB2-PTGS2 axis for therapeutic strategies.

Identification of miRNA-mRNA Pairs in Relation to TNF-α/IL-1β Induced Inflammatory Response in Intervertebral Disc Degeneration

Objective

The determination of miRNA-mRNA pairs for intervertebral disc degeneration (IVDD) regulated by pro-inflammatory cytokines were investigated.

Methods

Two dataset (accession number GSE27494 and GSE41883 from platform GPL1352) of expression profiling was downloaded from Gene Expression Omnibus (GEO). The annulus cells were isolated from annulus fibrosus in patients with degenerative disc disease. The cells were then cultured in a three-dimensional (3D) collagen containing with/without proinflammatory cytokines (tumor necrosis factor alpha (TNF-α) or interleukin beta (IL-1β)). After being cultured for 14 days, the isolated total RNA was analyzed via microarray, and the expression array data were obtained using BRB-Array Tools followed by analyzing the differentially expressed genes (DEGs) and the prediction of potential miRNA targets of hub genes through online database.

Results

Firstly, 52 and 296 DEGs were found in IL-1β- and TNF-α-induced annulus cells, respectively, of these there had 42 common DEGs (co-DEGs) with 34 increased transcripts and 8 reduced ones. Based on the GO and KEGG software, these co-DEGs were mainly enriched in the response to lipopolysaccharide (LPS) and molecule of bacterial origin, the regulation of receptor ligand activity and signaling receptor activator activity, as well as the following signaling pathways, including TNF signaling pathway, IL-17 signaling pathway, and NF-κB signaling pathway. Top hub genes (CXCL1, CXCL2, CXCL8, IL1Β and PTGS2) regulated by several potential microRNAs were involved in TNF-α/IL-1β treated annulus cells.

Conclusions

Several candidate genes regulated by miRNAs caused by TNF-α/IL-1β in the annulus cells were found, which will guide diagnosis and treatment for degenerative disc disease.

Regeneration of Damaged Tendon-Bone Junctions (Entheses)-TAK1 as a Potential Node Factor

Musculoskeletal dysfunctions are highly prevalent due to increasing life expectancy. Consequently, novel solutions to optimize treatment of patients are required. The current major research focus is to develop innovative concepts for single tissues. However, interest is also emerging to generate applications for tissue transitions where highly divergent properties need to work together, as in bone-cartilage or bone-tendon transitions. Finding medical solutions for dysfunctions of such tissue transitions presents an added challenge, both in research and in clinics. This review aims to provide an overview of the anatomical structure of healthy adult entheses and their development during embryogenesis. Subsequently, important scientific progress in restoration of damaged entheses is presented. With respect to enthesis dysfunction, the review further focuses on inflammation. Although molecular, cellular and tissue mechanisms during inflammation are well understood, tissue regeneration in context of inflammation still presents an unmet clinical need and goes along with unresolved biological questions. Furthermore, this review gives particular attention to the potential role of a signaling mediator protein, transforming growth factor beta-activated kinase-1 (TAK1), which is at the node of regenerative and inflammatory signaling and is one example for a less regarded aspect and potential important link between tissue regeneration and inflammation.