Asian Spine J.  2016 Dec;10(6):985-992. 10.4184/asj.2016.10.6.985.

Effect of RNA Interference-Mediated Suppression of p75 on the Viability of Rat Notochordal Cells

• Park JB
• Chang DG
• Oh SY
• Park EY

• KMID: 2362174
• DOI: http://doi.org/10.4184/asj.2016.10.6.985

Abstract

STUDY DESIGN: In vitro cell culture model. PURPOSE: To investigate the effects of RNA interference (RNAi) on p75 expression and viability of rat notochordal cells treated with serum deprivation. OVERVIEW OF LITERATURE: RNAi enables the inhibition of specific genes by sequence-specific gene silencing using a double-stranded RNA.
METHODS
Notochordal cells were isolated, cultured, and placed in 10% (control) or 0% (apoptosis-promoting) fetal bovine serum (FBS) for 48 hours. The expression of p75, apoptosis, and cell proliferation were determined. To suppress p75 expression, a small interfering RNA (siRNA) was synthesized against p75 (p75 siRNA) and transfected into cells. The suppression of p75 mRNA expression was investigated using the reverse transcription-polymerase chain reaction. The degree of p75 suppression was semiquantitatively analyzed using densitometry. The effect of p75 siRNA on apoptosis and proliferation of cells was determined. Solutions of an unrelated siRNA and transfection agent alone served as controls.
RESULTS
Serum deprivation significantly increased apoptosis by 40.3%, decreased proliferation of notochordal cells by 45.3% (both, p<0.001), and upregulated p75 expression. The p75 siRNA suppressed p75 expression in cells cultured in 0% FBS. The rate of suppression by p75 siRNA of p75 mRNA was 72.9% (p<0.001). Suppression of p75 expression by p75 siRNA inhibited apoptosis by 7% and increased proliferation by 14% in cells cultured in 0% FBS (both, p<0.05).
CONCLUSIONS
siRNA-mediated suppression of p75 inhibited apoptosis and increased proliferation of notochordal cells under conditions of serum deprivation, suggesting that RNAi might serve as a novel therapeutic approach for disc degeneration caused by insufficient viability of disc cells through the suppression of the expression of harmful genes.

Keyword

RNA interference; p75; Viability; Notochordal cells

MeSH Terms

Animals
Apoptosis
Cell Culture Techniques
Cell Proliferation
Densitometry
Gene Silencing
In Vitro Techniques
Intervertebral Disc Degeneration
Notochord*
Rats*
RNA Interference
RNA*
RNA, Double-Stranded
RNA, Messenger
RNA, Small Interfering
Transfection
RNA
RNA, Double-Stranded
RNA, Messenger
RNA, Small Interfering