Premium
Basal Endothelial Cell Autophagy is Elevated in Trained vs. Sedentary Mice
Author(s) -
Cho Jaemin,
Kim JiSeok,
Allsop Jeff,
Bean Tyler,
Bonn Trevor,
Hestwood Gabby,
Yang Kevin,
Drummond Micah,
Babu Pon Velayutham Anandh,
Symons J David
Publication year - 2017
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.31.1_supplement.840.25
Subject(s) - sed , autophagy , endocrinology , medicine , basal (medicine) , adventitia , chemistry , biochemistry , apoptosis , insulin
Autophagy is a process whereby damaged cellular cargo is delivered to the lysosome for degradation and eventual recycling or removal. A reduction of autophagy‐related (Atg) mRNA and protein expression in endothelial cells (ECs) from old rodents and humans is associated with arterial dysfunction. One study reports increased indices of autophagy in aortae from trained vs. sedentary rats (Sun et al., Cardiovascular Res , 2013), but the cellular subtypes were not evaluated. Exercise‐training could improve vascular health by upregulating EC autophagy. We hypothesized that exercise‐training increases basal EC autophagy. Five‐month old male C57Bl6 mice were treadmill‐trained (ETR, n=6, 32±1 g) or remained sedentary (SED, n=5, 32±1 g) 6 days per week. After 10‐weeks, total workload performed during a maximal exercise test was greater (p<0.05) in ETR (3.63±0.48 kgm) vs. SED animals (1.08± 0.22 kgm). 24 hours following the total workload test, soleus muscle, iliac artery, carotid artery, and aorta were obtained. The respiratory control ratio (RCR, state III to state IV respiration) was greater (p<0.05) in soleus from ETR (2.04±0.14) vs. SED mice (1.31±0.16). Citrate synthase activity (μmol/min/g) was greater (p<0.05) in soleus from ETR (0.99 ± 0.07) vs. SED (0.54 ± 0.14) mice. These findings verify the efficacy of our training protocol. ECs and media + adventitia (M+A) were obtained from the iliac and carotid arteries. mRNA expression was quantified by real‐time RT‐PCR using SYBR green fluorescence. Cycle threshold (Ct) values were normalized to the housekeeping gene 18S. Purity of the EC and M+A fractions obtained from carotid and iliac artery was confirmed by measuring PECAM‐1 and α‐SMA expression respectively. mRNA expression increased 1.8 – 4.1‐fold (p<0.05) for beclin‐1, LC3‐II, Atg3, Atg5, Atg7, Atg12, and Atg16 in iliac artery ECs, but not carotid artery ECs, from ETR vs. SED mice. All of these autophagy‐related genes in the M+A from iliac and carotid artery were similar in ETR and SED mice. LC3II:GAPDH and Atg3:GAPDH protein expression was greater (p<0.05) in aortic homogenates from ETR vs. SED mice. Collectively, exercise‐training increases the expression of autophagy‐related mRNA in iliac artery ECs, and autophagy‐related protein in arterial homogenates, relative to results obtained from sedentary animals. Ongoing experiments are determining whether exercise‐training increases basal expression of autophagy‐related mRNA and protein in the vasculature of old mice to an extent that attenuates age‐related arterial dysfunction. Support or Funding Information Supported by: UU Diabetes and Metabolism Center; UU Center on Aging; UU College of Health Research Committee; DRC at Washington University (5 P30 DK020579); and AHA 16GRNT31050004 (JDS).