Amphetamines promote mitochondrial dysfunction and DNA damage in pulmonary hypertension
Pin-I Chen, Aiqin Cao, Kazuya Miyagawa, Nancy F. Tojais, Jan K. Hennigs, Caiyun G. Li, Nathaly M. Sweeney, Audrey S. Inglis, Lingli Wang, Dan Li, Matthew Ye, Brian J. Feldman, Marlene Rabinovitch
Pin-I Chen, Aiqin Cao, Kazuya Miyagawa, Nancy F. Tojais, Jan K. Hennigs, Caiyun G. Li, Nathaly M. Sweeney, Audrey S. Inglis, Lingli Wang, Dan Li, Matthew Ye, Brian J. Feldman, Marlene Rabinovitch
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Research Article Cell biology Vascular biology

Amphetamines promote mitochondrial dysfunction and DNA damage in pulmonary hypertension

Abstract

Amphetamine (AMPH) or methamphetamine (METH) abuse can cause oxidative damage and is a risk factor for diseases including pulmonary arterial hypertension (PAH). Pulmonary artery endothelial cells (PAECs) from AMPH-associated-PAH patients show DNA damage as judged by γH2AX foci and DNA comet tails. We therefore hypothesized that AMPH induces DNA damage and vascular pathology by interfering with normal adaptation to an environmental perturbation causing oxidative stress. Consistent with this, we found that AMPH alone does not cause DNA damage in normoxic PAECs, but greatly amplifies DNA damage in hypoxic PAECs. The mechanism involves AMPH activation of protein phosphatase 2A, which potentiates inhibition of Akt. This increases sirtuin 1, causing deacetylation and degradation of HIF1α, thereby impairing its transcriptional activity, resulting in a reduction in pyruvate dehydrogenase kinase 1 and impaired cytochrome c oxidase 4 isoform switch. Mitochondrial oxidative phosphorylation is inappropriately enhanced and, as a result of impaired electron transport and mitochondrial ROS increase, caspase-3 is activated and DNA damage is induced. In mice given binge doses of METH followed by hypoxia, HIF1α is suppressed and pulmonary artery DNA damage foci are associated with worse pulmonary vascular remodeling. Thus, chronic AMPH/METH can induce DNA damage associated with vascular disease by subverting the adaptive responses to oxidative stress.

Authors

Pin-I Chen, Aiqin Cao, Kazuya Miyagawa, Nancy F. Tojais, Jan K. Hennigs, Caiyun G. Li, Nathaly M. Sweeney, Audrey S. Inglis, Lingli Wang, Dan Li, Matthew Ye, Brian J. Feldman, Marlene Rabinovitch

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Figure 9

Methamphetamine and hypoxia increase γH2AX foci in mouse pulmonary arteries (PAs) and pulmonary vascular remodeling and impaired HIF1α gene regulation.

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Methamphetamine and hypoxia increase γH2AX foci in mouse pulmonary arter...
Mice were treated with 10 mg/kg methamphetamine (METH) twice daily for 3 days in room air, and then exposed to 10% O2 hypoxia for 4 days, and the cycle repeated for a total of 4 weeks. (A and B) Mouse lung sections were immunostained for von Willebrand factor (vWF, green), DAPI (blue), and α-smooth muscle actin (α-SMA) (A) or γH2AX (B) (red), to indicate the PA endothelial cell layer, nuclei, muscularization, and DNA damage foci, respectively. (A) Representative images of muscularized distal PAs (DPAs), indicated by arrows. Scale bar: 80 μm. Scatter plot on the right shows the percentage of fully, partially, and nonmuscularized DPAs, scored based on 4 to 5 confocal images taken for each mouse. (B) Representative images of PAs immunostained for γH2AX. Scale bar: 20 μm. Insets show magnified areas of endothelial cells with γH2AX foci. Scale bar; 8 μm. Right, γH2AX foci were scored using ImageJ, in 10 to 15 confocal images of PAs for each mouse. (C) Lung homogenates from the mice were immunoblotted for SIRT1, HIF1α, p-Akt, PDK1, α-SMA, PDK1, cCasp3, COX4I1, and β-actin (loading control). Each lane represents lung lysate of one mouse. Dot plots in A–C represent mean ± SEM; n = 5, vehicle-treated (Veh) group and n = 5–6, METH group. *P < 0.05, **P < 0.005, ****P < 0.0001 vs. vehicle by unpaired t test.