Fenoldopam-mediated increase in autophagy associates with recruiting WIPI2 protein in early endosomes in vascular smooth muscle cells

Abstract

Autophagy, a crucial cellular homeostatic process, has protective roles in the pathogenesis of hypertension. Dopamine, a monoamine neurotransmitter, regulates autophagy in the kidney and vascular system. However, the exact roles and mechanisms of dopaminergic system on the regulation of autophagy is not well known. In rat aortic vascular smooth muscle cells, fenoldopam (FEN, 25 nM/15 min), a D1-like receptor agonist, increased the ATG5 and LC3-II (a late autophagosome maker) protein expression. Consistently, FEN decreased p62/SQSTM1 protein expression. The FEN-mediated increase in ATG5 was attenuated by SCH39166 (1 μM/15 min), a D1- like receptor antagonist, indicating that FEN increased autophagy in the autophagosome formation stage through its D1-like receptors. FEN increased the protein expression of WD Repeat Domain, Phosphoinositide Interacting 2 (WIPI2) in a concentration- and time-dependent manner, which is important in the early steps of autophagosome formation. FEN (25 nM, 15 min) increased the WIPI2 puncta fluorescence intensity and the colocalization of WIPI2 with EEA1 (Veh: 7.12±1.1% vs FEN: 9.96±0.9%, N=5, P < 0.001, Student’s t test), a typical phosphatidylinositol-3-phosphate binding protein in early endosomes, indicating that WIPI2 recruitment in early endosomes is important in the early stage of FEN-mediated autophagic process. Taken together, FEN increases autophagy with WIPI2 recruitment in the early endosomes in vascular smooth muscle cells. This work was supported by US National Institutes of Health grants R01DK134574 and R01DK119652. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.