Targeting myoferlin by 6-shogaol inhibition regulates hyperglycemia-induced retinal vascular dysfunction.

BACKGROUND: Hyperglycemic stress induces the dysfunction of endothelial cells, disrupting the microvascular stabilization and remodeling. Our previous study found that Ginger-Coptis formula, a traditional Chinese medicine (TCM) formula, significantly ameliorated diabetic retinopathy, and 6-shogaol was identified as one of the possible contributive compounds.

OBJECTIVE: This study aims to investigate the pharmacological effects of 6-shogaol, a key bioactive compound in ginger (Zingiber officinal Roscoe), as a novel inhibitor for myoferlin (MYOF). It also proposes to demonstrate the regulatory effects of 6-shogaol on vascular endothelial growth factor receptor 2 (VEGFR2)/ protein kinase B (Akt)/endothelial nitric oxide synthase (eNOS) signaling in hyperglycemia-induced retinal vasculature as potential molecular mechanisms.

METHODS: The stable isotope labeling by amino acids in cell culture (SILAC) was used to identify the direct binding protein by 6-shogaol under high glucose. The inhibitory activity of 6-shogaol on MYOF was evaluated by cellular assays. Both in vitro assays and streptozotocin-induced diabetic mouse models were used to investigate the effects of 6-shogaol. A structure-activity relationship was conducted to explore the structural basis of 6-shogaol that may contribute to the inhibition of targeted protein function and the angiogenic response to high glucose. The mechanisms were further confirmed by overexpression of targeted proteins in vivo.

RESULTS: 6-Shogaol potentially targeted MYOF in retinal endothelial cells and inhibited its function on the regulating the stability and activity of VEGFR2, which reduced the angiogenic responses in the retinal endothelial cells under high glucose. The potential mechanism involved the downregulation of VEGFR2/Akt/eNOS pathway. These effects of 6-shogaol might be associated with structural features such as its α,β-unsaturated ketone moiety. 6-Shogaol had the therapeutic potential of alleviating the retinal vascular dysfunction in diabetic mice.

CONCLUSION: Our study demonstrated 6-shogaol as a promising therapeutic candidate and highlighted MYOF as a druggable target for the diabetic retinopathy treatment.