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 5

Suppression of p-Akt by amphetamine stabilizes SIRT1 under hypoxia (See also Supplemental Figure 3).

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Suppression of p-Akt by amphetamine stabilizes SIRT1 under hypoxia (See ...
(A) Pulmonary artery endothelial cells (PAECs) were treated with 0.5 mM amphetamine (AMPH) for the indicated times under normoxia (Nx) or hypoxia (Hx), and cell lysates were immunoblotted for phospho-SIRT1 (p-SIRT1), SIRT1, p-Akt, p-JNK, and β-actin (loading control). (B) PAECs were transfected with vector (Vec) or HA-tagged myristoylated Akt1 (myr-Akt) construct. Twenty-four hours after transfection, cells were treated daily with 0.5 mM AMPH for 3 days and then cultured with vehicle (Veh) or AMPH under Nx or Hx for 48 hours, and SIRT1, myr-Akt, and β-actin (loading control) protein levels were analyzed by immunoblotting. Dot and line graphs represent mean ± SEM, n = 3–4. **P < 0.005, ***P < 0.0005 vs. Nx+Veh; ##P < 0.005 vs. Hx+Veh; &P < 0.05, &&&P < 0.0005 vs. Hx+AMPH; by 2-way ANOVA, Bonferroni’s post-test.