Asian Spine J.  2017 Dec;11(6):863-869. 10.4184/asj.2017.11.6.863.

Detection of O-Linked-N-Acetylglucosamine Modification and Its Associated Enzymes in Human Degenerated Intervertebral Discs

• Nikolaou G
• Zibis AH
• Fyllos AH
• Katsioulis A
• Sotiriou S
• Kotrotsios A
• Sgantzos M
• Vassiou A
• Arvanitis

• KMID: 2397623
• DOI: http://doi.org/10.4184/asj.2017.11.6.863

Abstract

STUDY DESIGN: Human herniated discs were obtained from discectomy specimens for the immunohistochemical detection of O-GlcNAc and O-GlcNAcase (OGA)/O-GlcNAc transferase (OGT). PURPOSE: This study aimed to quantify the extent of O-GlcNAcylation and its associated enzymes (OGT/OGA) in human degenerated intervertebral discs. OVERVIEW OF LITERATURE: The O-GlcNAcylation of nuclear, cytoplasmic, and mitochondrial proteins as well as the effects of such post-translational modifications are currently the focus of extensive research. O-GlcNAcylation is believed to contribute to the etiology of chronic illnesses by acting as a nutrient and stress sensor in the cellular environment. Mature intervertebral disc cells are chondrocyte-like cells, and O-GlcNAc has been shown to promote chondrocyte apoptosis in vitro. We believe that O-GlcNAcylation is a key regulator of disc degeneration.
METHODS
Fifty-six specimens were fixed for 24 hours in a 10% solution of neutral-buffered formaldehyde, dehydrated, and embedded in paraffin. Tissue slices (4-µm-thick) were used for hematoxylin-eosin staining and immunohistochemistry.
RESULTS
We found that O-GlcNAcylation of cytoplasmic proteins was less than that of nuclear proteins in both single cells and cell clusters. Cytoplasmic O-GlcNAcylation occurs subsequent to nuclear O-GlcNAcylation and is directly proportional to disc degeneration. OGT and O-GlcNAc expression levels were identical in all specimens examined.
CONCLUSIONS
O-GlcNAc and OGA/OGT expression is shown to correlate for the first time with intervertebral disc cell degeneration. Increasing disc degeneration is associated with increasing O-GlcNAcylation in both nuclear and cytoplasmic proteins in human disc cells.

Keyword

Spine; Enzymes; Intervertebral disc degeneration; Immunohistochemistry

MeSH Terms

Apoptosis
Chondrocytes
Chronic Disease
Cytoplasm
Diskectomy
Formaldehyde
Humans*
Immunohistochemistry
In Vitro Techniques
Intervertebral Disc Degeneration
Intervertebral Disc Displacement
Intervertebral Disc*
Mitochondrial Proteins
Nuclear Proteins
Paraffin
Protein Processing, Post-Translational
Spine
Transferases
Formaldehyde
Mitochondrial Proteins
Nuclear Proteins
Paraffin
Transferases