HIV-1 gp120 and tobacco smoke synergistically disrupt the integrity of the blood-brain barrier

In the United States, the Centers for Disease Control and Prevention (CDC) terms HIV and tobacco use among the ten most important public health challenges we face today. In the last decade, there has been a remarkable decrease in the number of deaths due to HIV/AIDS, especially after the widespread availability and use of combination antiretroviral therapy (cART). However, people living with HIV/AIDS have a heightened risk of chronic complications and comorbidities, including neurological disorders. Around 40-60 % of HIV-infected individuals progress to NeuroAIDS, a group of disorders caused primarily by HIV-mediated damage to the central and peripheral nervous systems, despite receiving cART. The detrimental effects of chronic smoking on the cerebrovascular system are also well studied and reported. Addictive behavior, such as smoking, is more common in HIV patients compared to the general population. In this context, given the existing immune suppression, smoking can pose a significant risk for the progression of the disease to NeuroAIDS by disrupting the integrity of the blood-brain barrier (BBB). Here we show that co-treatment with Tobacco Smoke Extract (TSE) and HIV-1 gp120 (HIV envelope glycoprotein) in primary cultures of human brain microvascular endothelial cells promoted heightened cellular stress responses compared to control and individual treatments. Our findings suggest that a potential synergistic effect between smoke exposure and gp120 can worsen the loss of BBB viability, possibly exacerbating NeuroAIDS progression.