PEX11B palmitoylation couples peroxisomal dysfunction with Schwann cells fail in diabetic neuropathy

Diabetic neuropathy (DN) is a prevalent and painful complication of diabetes; however, the mechanisms underlying its pathogenesis remain unclear, and effective clinical treatments are lacking. This study aims to explore the role of peroxisomes in Schwann cells in DN.

The abundance of peroxisomes in the sciatic nerves of mice or Schwann cells was analyzed using laser confocal super-resolution imaging and western blotting. The RFP-GFP-SKL (Ser-Lys-Leu) probe was utilized to assess pexophagy (peroxisomes autophagy) levels. To evaluate the palmitoylation of PEX11B, the acyl-resin assisted capture (acyl-RAC) assay and the Acyl-Biotin Exchange (ABE) assay were employed. Additionally, MR (Mendelian randomization) analysis was conducted to investigate the potential causal relationship between DN and MS (Multiple sclerosis).

There was a decrease in peroxisomal abundance in the sciatic nerves of diabetic mice, and palmitic acid (PA) induced a reduction in peroxisomal abundance by inhibiting peroxisomal biogenesis in Schwann cells. Mechanistically, PA induced the palmitoylation of PEX11B at C25 site, disrupting its self-interaction and impeding peroxisome elongation. Fenofibrate, a PPARα agonist, effectively rescued peroxisomal dysfunction caused by PA and restored the peroxisomal abundance in diabetic mice. Lastly, MR analysis indicates a notable causal influence of DN on MS, with its onset and progression intricately linked to peroxisomal dysfunction.

Targeting the peroxisomal biogenesis pathway may be an effective strategy for preventing and treating DN, underscoring the importance of addressing MS risk at the onset of DN.