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Role of AMPK in Adiponectin‐Mediated Restoration of Nitric Oxide‐Dependent Flow Induced Dilation in the Human Microvasculature
Author(s) -
Cohen Katie E.,
Schulz Mary E.,
Gutterman David D.,
Freed Julie K.
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.03319
Subject(s) - adiponectin , ampk , nitric oxide , chemistry , medicine , endocrinology , adipose tissue , arteriole , protein kinase a , biochemistry , kinase , microcirculation , insulin , insulin resistance
Flow‐induced dilation (FID), the ability of an arteriole to dilate in response to increased flow, is primarily mediated by endothelial‐derived nitric oxide (NO) in healthy individuals, however is replaced by hydrogen peroxide (H 2 O 2 ) in patients with coronary artery disease (CAD). Our laboratory has shown that adiponectin restores NO‐mediated FID in microvessels from patients with CAD. Adiponectin activates multiple signaling pathways that promote NO formation, including activation of neutral ceramidase to hydrolyze ceramide, a sphingolipid that in elevated amounts promotes FID mediated by H 2 O 2 . Our prior work has shown that both NO and H 2 O 2 contribute as mediators of FID in diseased vessels treated with adiponectin and ceranib‐1, an inhibitor of neutral ceramidase. As adiponectin is also capable of activating AMP kinase (AMPK) to increase cellular NO levels, we tested the hypothesis that AMPK activation is required to restore NO‐mediated FID in diseased arterioles. Human microvessels (80–200μm) were dissected from adipose tissue collected from patients diagnosed with CAD. Following cannulation and equilibration, vessels were constricted with endothelin‐1. Using videomicroscopy, vessel diameters were measured in response to graded increases in intraluminal flow. To investigate whether activation of AMPK is a key mechanistic step in adiponectin‐induced restoration of NO‐mediated signaling, vessels from patients diagnosed with CAD were first treated with the AMPK inhibitor Compound C (1μM, 4hrs) followed by adiponectin treatment (2μg/mL, 16–20hrs). Dilation to flow was maintained during exposure to the nitric oxide synthase (NOS) inhibitor L‐NAME (100μM) (69.8% max dilation±2.7, n=2) as well as in the presence of the PEG‐Catalase (500U) (64.5%±21.2, n=4) compared to compound C and adiponectin alone (61.0%±9.4, n=4). To determine whether ceramide hydrolysis via neutral ceramidase contributes to the maintained dilation despite NOS inhibition, FID was also assessed in diseased arterioles treated with both compound C and ceranib‐1 prior to treatment with adiponectin. Both NO and H 2 O 2 contributed to dilation under both AMPK and neutral ceramidase inhibition as dilation was observed in the presence of L‐NAME (33.6%±15.9, n=3) or PEG‐Catalase (51.7%±23.9, n=3). However, FID was decreased during exposure to both L‐NAME and PEG‐Catalase (11.6%±12.4, n=2). These preliminary data suggest that adiponectin promotes NO formation through multiple pathways and contributes to the redundancy of endothelial‐derived mediators in order to maintain FID. Support or Funding Information This research was supported by National Institute of Health (NHLBI) K08HL141562 (J.K.F.) and National Institute of Health 5R38HL143561‐02 (M.E.W.).