Adipose-derived mesenchymal stem cells overexpressing prion improve outcomes via the NLRP3 inflammasome/DAMP signalling after spinal cord injury in rat.

Abstract

Traumatic spinal cord injury (SCI) is a highly destructive disease in human neurological functions. Adipose-derived mesenchymal stem cells (ADMSCs) have tissue regenerations and anti-inflammations, especially with prion protein overexpression (PrPcOE ). Therefore, this study tested whether PrPcOE -ADMSCs therapy offered benefits in improving outcomes via regulating nod-like-receptor-protein-3 (NLRP3) inflammasome/DAMP signalling after acute SCI in rats. Compared with ADMSCs only, the capabilities of PrPcOE -ADMSCs were significantly enhanced in cellular viability, anti-oxidative stress and migration against H2 O2 and lipopolysaccharide damages. Similarly, PrPcOE -ADMSCs significantly inhibited the inflammatory patterns of Raw264.7 cells. The SD rats (n=32) were categorized into group 1 (Sham-operated-control), group 2 (SCI), group 3 (SCI + ADMSCs) and group 4 (SCI + PrPcOE -ADMSCs). Compared with SCI group 2, both ADMSCs and PrPcOE -ADMSCs significantly improved neurological functions. Additionally, the circulatory inflammatory cytokines levels (TNF-α/IL-6) and inflammatory cells (CD11b/c+/MPO+/Ly6G+) were highest in group 2, lowest in group 1, and significantly higher in group 3 than in group 4. By Day 3 after SCI induction, the protein expressions of inflammasome signalling (HGMB1/TLR4/MyD88/TRIF/c-caspase8/FADD/p-NF-κB/NEK7/NRLP3/ASC/c-caspase1/IL-ß) and by Day 42 the protein expressions of DAMP-inflammatory signalling (HGMB1/TLR-4/MyD88/TRIF/TRAF6/p-NF-κB/TNF-α/IL-1ß) in spinal cord tissues displayed an identical pattern as the inflammatory patterns. In conclusion, PrPcOE -ADMSCs significantly attenuated SCI in rodents that could be through suppressing the inflammatory signalling.