CX3CL1 Derived from Bone Marrow Mesenchymal Stem Cells Inhibits A β 1-42-Induced SH-SY5Y Cell Pathological Damage through TXNIP/NLRP3 Signaling Pathway

Abstract

Alzheimer's disease (AD) is the most commonly seen neurodegenerative brain disorder. The paracrine effects of mesenchymal stem cells (MSCs) signify to trigger immunomodulation and neural regeneration. However, the role and mechanism of bone marrow MSC- (BMSC-) derived CX3CL1 in AD remains elusive. In this study, Aβ _1-42-intervened SH-SY5Y cells were used for AD cell model construction. pcDNA-ligated CX3CL1 overexpression plasmids were transfected into BMSCs. The levels of soluble and membrane-bound CX3CL1 were detected by ELISA and Western blotting (WB), respectively. The growth, apoptosis, and pathology of AD model cells were evaluated by CCK-8, flow cytometry, immunofluorescence, morphology observation, biochemical examination, and WB. It was found that Aβ _1-42 significantly reduced CX3CL1 expression either in soluble or membrane-bound form, cell viability, relative protein expression of synaptic markers, SOD, CAT, and GSH-Px contents, as well as Trx protein expression; in addition, it enhanced the apoptosis rate, the relative expression of cleaved caspase-3, Aβ, tau, p-Tau, Iba1, MDA, TXNIP, and NLRP3 in SH-SY5Y cells; however, the above effects were prominently reversed by the coculture of BMSCs. Moreover, overexpression of CX3CL1 in BMSCs observably strengthened the corresponding tendency caused by BMSCs. In conclusion, through the TXNIP/NLRP3 pathway, CX3CL1 derived from BMSCs inhibited pathological damage in Aβ _1-42-induced SH-SY5Y.

Figure 1

CX3CL1 derived from BMSCs significantly inverted Aβ_1-42-decreased CX3CL1 in SH-SY5Y. (a) Soluble CX3CL1 expression in BMSCs was detected by ELISA. (b and c) Western blotting determined CX3CL1 expression relative to β-actin in BMSCs. (d) ELISA measured soluble CX3CL1 levels in SH-SY5Y under different interventions. (e and f) Western blotting examined CX3CL1 expression relative to β-actin in SH-SY5Y under different interventions. ns: nonsignificance; ^∗p < 0.05 versus control group; ^#p < 0.05 versus Aβ group; ^&p < 0.05 versus Aβ+MSC group.

Figure 2

CX3CL1 derived from BMSCs statistically augmented Aβ_1-42-induced SH-SY5Y viability but repressed apoptosis. (a) CCK-8 assay assessed SH-SY5Y viability. (b and c) Flow cytometry evaluated SH-SY5Y apoptosis. (d and e) Western blotting determined cleaved caspase-3 expression relative to β-actin. ^∗p < 0.05 versus control group; ^#p < 0.05 versus Aβ group; ^&p < 0.05 versus Aβ+MSC group.

Figure 3

CX3CL1 derived from BMSCs alleviated the pathology-induced Aβ_1-42 in SH-SY5Y. (a–d) Western blotting examined Aβ, tau, and p-Tau protein expressions relative to β-actin. (e and f) The relative integrated density of Iba1 was evaluated by IF. (g) The axons of SH-SY5Y cells were observed using inverted microscope. (h–k) Western blotting examined SNAP25, Synapsin1, and PSD95 protein levels relative to β-actin. ^∗p < 0.05 versus control group; ^#p < 0.05 versus Aβ group; ^&p < 0.05 versus Aβ+MSC group.

Figure 4

The role played by CX3CL1 derived from BMSCs in Aβ_1-42-induced SH-SY5Y was related to TXNIP/NLRP3 axis. (a–d) MDA, SOD, CAT, and GSH-Px concentrations measured by commercial kits. (e–h) Western blotting tested TXNIP, NLRP3, and Trx protein levels relative to β-actin. ^∗p < 0.05 versus control group; ^#p < 0.05 versus Aβ group; ^&p < 0.05 versus Aβ+MSC group.