Small Interfering RNA-Mediated Suppression of Fas Modulate Apoptosis and Proliferation in Rat Intervertebral Disc Cells

Inhibitory Effect of Insulin Treatment on Apoptosis of Intervertebral Disc Cells in a Streptozotocin-Induced Diabetic Rat Model

STUDY DESIGN

Experimental study using a streptozotocin (STZ)-induced diabetic rat model.

PURPOSE

This study aims to investigate whether insulin treatment could attenuate disc cell apoptosis and matrix degradation in a STZ-induced diabetic rat model.

OVERVIEW OF LITERATURE

Diabetes is a significant risk factor for disc degeneration due to excessive apoptosis of disc cells and matrix degradation. However, no studies were noted to demonstrate the inhibitory effect of insulin treatment on the apoptosis of disc cells and matrix degradation in diabetic patients.

METHODS

Rats were allocated randomly into one of three groups: control, STZ, and STZ-insulin. Diabetes was induced by a single intraperitoneal injection of STZ (65 mg/kg) in the STZ and STZ-insulin groups. The blood glucose level was consistently above 400 mg/ dL in the STZ and STZ-insulin groups 2 weeks after STZ injection. After 2 weeks of STZ injection, the STZ-insulin group was administered insulin treatment (1.5 unit/100 g) daily for up to 4 weeks. Blood glucose of the STZ-insulin rats significantly decreased to normal levels 4 weeks after insulin treatment. The rats were sacrificed 6 weeks after STZ injection, and disc cells and tissues were harvested to investigate the expression of apoptosis markers and matrix metalloproteinases (MMPs).

RESULTS

Fas and caspase-8, -9, and -3 expressions were significantly increased in the STZ group, along with increased expressions of MMP-2 and -3. On the contrary, insulin treatment significantly decreased the expressions of Fas, caspase-8, -9, and -3 as well as MMP-2 and -3 in the STZ-insulin group.

CONCLUSIONS

The results of the current study demonstrated that insulin treatment attenuates excessive apoptosis of disc cells and matrix degradation in the diabetic rat model. Accordingly, strict blood glucose control should be recommended to prevent disc degeneration in diabetic patients.

Circular RNA hsa_circ_0001658 Inhibits Intervertebral Disc Degeneration Development by Regulating hsa-miR-181c-5p/FAS

METHODS

We obtained microarray data (GSE116726, GSE67566) from Gene Expression Omnibus database, and differential expression level of ncRNA in nucleus pulposus (NP) tissues of IDD patients was analyzed. The potential circRNA-miRNA-mRNA regulatory network was analyzed by starBase. The effect of the interaction between hsa_circ_0001658, hsa-miR-181c-5p, and FAS on the proliferation and apoptosis of human neural progenitor cells (hNPCs) was studied.

RESULTS

hsa_circ_0001658 was significantly upregulated (logFC > 2.0 and adj.P.Val < 0.01) in the NP tissues of IDD patients, and hsa-miR-181c-5p expression was downregulated (logFC < -2.0 and adj.P.Val < 0.01). Silencing of hsa-miR-181c-5p or overexpression of hsa_circ_0001658 inhibited the proliferation of hNPCs and promoted their apoptosis. hsa_circ_0001658 acted as a sponge of hsa-miR-181c-5p. hsa-miR-181c-5p downregulated the expression of Fas cell surface death receptor (FAS), promoted the proliferation, and inhibited the apoptosis of hNPCs. hsa_circ_0001658 functioned in hNPCs through targeting hsa-miR-181c-5p/FAS.

CONCLUSION

Circular RNA hsa_circ_0001658 inhibits IDD development by regulating hsa-miR-181c-5p/FAS. It is expected to be a potential target for the therapy of IDD.

Targeted therapy for intervertebral disc degeneration: inhibiting apoptosis is a promising treatment strategy

Intervertebral disc (IVD) degeneration (IDD) is a multifactorial pathological process associated with low back pain (LBP). The pathogenesis is complicated, and the main pathological changes are IVD cell apoptosis and extracellular matrix (ECM) degradation. Apoptotic cell loss leads to ECM degradation, which plays an essential role in IDD pathogenesis. Apoptosis regulation may be a potential attractive therapeutic strategy for IDD. Previous studies have shown that IVD cell apoptosis is mainly induced by the death receptor pathway, mitochondrial pathway, and endoplasmic reticulum stress (ERS) pathway. This article mainly summarizes the factors that induce IDD and apoptosis, the relationship between the three apoptotic pathways and IDD, and potential therapeutic strategies. Preliminary animal and cell experiments show that targeting apoptotic pathway genes or drug inhibition can effectively inhibit IVD cell apoptosis and slow IDD progression. Targeted apoptotic pathway inhibition may be an effective strategy to alleviate IDD at the gene level. This manuscript provides new insights and ideas for IDD therapy.