Demethylase FTO promotes neuropathic pain development via regulating the m6A methylation levels of CXCR3.

OBJECTIVE
Neuropathic pain (NPP) is an indirect or direct pain caused by somatic sensory nervous system dysfunction or primary injury, which is considered to be one of the most serious public health problems. This study aimed to investigate the role of adiposity-associated protein (FTO) in NPP.


MATERIALS AND METHODS
Sciatic nerve injury (SNI) treatment was performed to establish an NPP model in vivo. The qRT-PCR and western blot assays were conducted to measure the relative mRNA and protein expressions. Additionally, the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) of the mice were measured on days 0, 1, 3, 5, 7, and 14. The m6A level of CXCR3 was determined with Methylated RNA immunoprecipitation (MeRIP) assay and the inflammatory factor expressions were determined with Elisa kits.


RESULTS AND DISCUSSION
The FTO and CXCR3 expressions were up-regulated and the METTL14 expression was down-regulated in SNI mice. FTO-silenced increased the m6A and decreased the mRNA levels of CXCR3 in SNI mice. Furthermore, FTO-silenced decreased the mRNA stability of the CXCR3. Besides, in the SNI mice, FTO-silenced increased the PWL and PWT, and decreased the TNF-α, IL-1β, and IL-6 levels. While over-expressed CXCR3 inverted the FTO-silenced effects.


CONCLUSIONS
Knockdown of FTO relieved the NPP progression via triggering the demethylation of CXCR3, thereby down-regulating the CXCR3expression.