Expression and activity of hyaluronidases HYAL-1, HYAL-2 and HYAL-3 in the human intervertebral disc

Abstract

Purpose Hyaluronic acid plays an essential role in water retention of the intervertebral disc (IVD) and thus provides flexibility and shock absorbance in the spine. Hyaluronic acid gets degraded by hyaluronidases (HYALs), and some of the resulting fragments were previously shown to induce an inflammatory and catabolic response in human IVD cells. However, no data currently exist on the expression and activity of HYALs in IVD health and disease. Methods Gene expression, protein expression and activity of HYALs were determined in human IVD biopsies with different degrees of degeneration (n = 50 total). Furthermore, freshly isolated human IVD cells (n = 23 total) were stimulated with IL-1β, TNF-α or H 2 O 2 , followed by analysis of HYAL-1, HYAL-2 and HYAL-3 gene expression. Results Gene expression of HYAL-1 and protein expression of HYAL-2 significantly increased in moderate/severe disc samples when compared to samples with no or low IVD degeneration. HYAL activity was not significantly increased due to high donor-donor variation, but seemed overall higher in the moderate/severe group. An inflammatory environment, as seen during IVD disease, did not affect HYAL-1, HYAL-2 or HYAL-3 expression, whereas exposure to oxidative stress (100 µM H 2 O 2) upregulated HYAL-2 expression relative to untreated controls. Conclusion Although HYAL-1, HYAL-2 and HYAL-3 are all expressed in the IVD, HYAL-2 seems to have the highest pathophysiological relevance. Nonetheless, further studies will be needed to comprehensively elucidate its significance and to determine its potential as a therapeutic target.

Efficacy of hyaluronic acid on intervertebral disc inflammation: An in vitro study using notochordal cell lines and human disc cells

“…21,22,27,27,28 Recently, Krupkova et al have reported that HYAL1, HYAL2, and HYAL3 were expressed in human IVDs, and that the mRNA expression of HYAL1 and the protein expression of HYAL2 were significantly increased in moderate/severe IVDD samples. 50 Our analysis using immunohistochemistry showed elevated expression of HYAL1, HYAL2, and CEMIP in highly degenerated IVD tissues. The expression of all three molecules, with a significant difference only in HYAL1, showed an increasing tendency in accordance with progression of IVDD.…”

Elucidating the genetic effect of vitamin D on mesenchymal stem cell differentiation in vitro

“…Hyaluronidases intracellularly degrade hyaluronan, one of the major glycosaminoglycans of the extracellular matrix (ECM). Hyaluronan is involved in cell proliferation, migration and differentiation and forms a major component of the ECM of cartilage, thus contributing to the structural and functional integrity of the bone [33,34]. Whilst vitamin D increased the expression of HYAL3 in all conditions, the presence of signi cantly higher fold increase found in the GM-treated group alone suggests that vitamin D may play an underappreciated role in regulating the extracellular matrix (ECM) via the MSCs.…”

Prediction of a Potential Mechanism of Intervertebral Disc Degeneration Based on a Novel Competitive Endogenous RNA Network

“…HYAL1 encodes lysosomal hyaluronidase, which degrades HA in cells. In one study, the gene expression of HYAL1 and the protein expression of HAYL2 were significantly increased in moderate/severe IDD samples compared with those without or with low IDD [ 37 ]. The protein encoded by LYVE1 acts as a receptor and binds to both soluble and fixed HA and may also play a role in lymphatic HA transport.…”