Conclusions
Unfolded protein response reinforces the survival and proliferation of NPCs under TNF-α stimulation by activating the XBP1 pathway, and NF-κB serves as a vital mediator in these events. The XBP1 signalling of UPR can be a novel therapeutic target in IDD.
Methods
Rat NPCs were cultured with TNF-α in the presence or absence of XBP1 and NF-κB-p65 small interfering RNA. The associated genes and proteins were evaluated through quantitative real-time PCR, Western blot analyses and immunofluorescence staining to monitor UPR and NF-κB signalling and identify the regulatory mechanism of p65 by XBP1. Cell counting kit-8 assay, cell cycle analysis and related gene and protein expression were performed to examine the proliferation of NPCs.
Results
The acute exposure of TNF-α accelerated the proliferation of rat NPCs by activating the UPR/XBP1 pathway. XBP1 signalling favoured the phosphorylation and nuclear translocation of p65 subunit of NF-κB. The activation of NF-κB in the later phase also enhanced NPC proliferation. Conclusions: Unfolded protein response reinforces the survival and proliferation of NPCs under TNF-α stimulation by activating the XBP1 pathway, and NF-κB serves as a vital mediator in these events. The XBP1 signalling of UPR can be a novel therapeutic target in IDD.