The Antiretroviral Protease Inhibitor Ritonavir Accelerates Glutathione Export from Cultured Primary Astrocytes

Abstract

Antiretroviral protease inhibitors are a class of important drugs that are used for the treatment of human immunodeficiency virus infections. Among those compounds, ritonavir is applied frequently in combination with other antiretroviral protease inhibitors, as it has been reported to boost their therapeutic efficiency. To test whether ritonavir affects the viability and the glutathione (GSH) metabolism of brain cells, we have exposed primary astrocyte cultures to this protease inhibitor. Application of ritonavir in low micromolar concentrations did not compromise cell viability, but caused a time- and concentration-dependent loss of GSH from the cells which was accompanied by a matching increase in the extracellular GSH content. Half-maximal effects were observed for ritonavir in a concentration of 3 μM. The ritonavir-induced stimulated GSH export from astrocytes was completely prevented by MK571, an inhibitor of the multidrug resistance protein 1. In addition, continuous presence of ritonavir was essential to maintain the stimulated GSH export, since removal of ritonavir terminated the stimulated GSH export. Ritonavir was more potent to stimulate GSH export from astrocytes than the antiretroviral protease inhibitors indinavir and nelfinavir, but combinations of ritonavir with indinavir or nelfinavir did not further stimulate astrocytic GSH export compared to a treatment with ritonavir alone. The strong effects of ritonavir and other antiretroviral protease inhibitors on the GSH metabolism of astrocytes suggest that a chronic treatment of patients with such compounds may affect their brain GSH metabolism.

Glutathione-Dependent Detoxification Processes in Astrocytes

“…Recently a number of compounds have been reported to strongly stimulate rapid GSH export from viable astrocytes, including formaldehyde [96], arsenate and arsenite [97,98] and antiretroviral protease inhibitors [99,100]. Although all of these stimulated GSH export processes were almost completely prevented by inhibition of Mrp1, the molecular mechanism how such structurally very diverse compounds accelerate Mrp1-mediated GSH export remains unclear.…”

Effect of DJ-1 on the neuroprotection of astrocytes subjected to cerebral ischemia/reperfusion injury

“…GSH is an important antioxidant in the brain that participates in interactions between astrocytes and neurons [ 20 – 22 ]. Previous studies have shown that GSH is synthesized and released by astrocytes and can then be used by neurons to resist oxidative stress [ 21 , 23 ]. In addition, elevated DJ-1 expression increases GSH levels in co-cultures of astrocytes and neurons [ 24 ], but it is not clear how these two molecules interact.…”

Astrocyte Senescence and Metabolic Changes in Response to HIV Antiretroviral Therapy Drugs

“…While beneficial in their suppression of HIV, HAART drugs have a multitude of side effects including myopathy, hepatotoxicity, hypersensitivity reactions, lipodystrophy, and insulin resistance ( Feeney and Mallon, 2010 ). In vitro , there has been evidence of HAART drugs inducing ER stress ( Sato et al, 2012 ), unfolded protein response ( Zhou et al, 2005 ), and changes to cellular metabolism ( Arend et al, 2013 ). These side effects suggest that cells may undergo a great deal of stress in response to HAART drugs.…”