The study shows that a short piece of the hormone kisspeptin (kisspeptin‑10) can protect brain blood vessels from damage caused by a HIV protein called Tat. In mice and brain‑cell cultures, kisspeptin‑10 reduced oxidative stress, lowered inflammation, kept the tight junction protein Claudin‑5 high, and blocked a cell‑signaling pathway (RhoA/ROCK) that normally makes the blood‑brain barrier leaky.

This study investigated the effects of Kisspeptin-10 (Kp-10) on HIV-1 Tat-induced blood-brain barrier (BBB) permeability and oxidative stress using both in vivo and in vitro models. In vivo, one hour after intraperitoneal administration of 50 nmol/kg (DSS)*6-Kp-10, mice were intravenously injected with HIV-1 Tat (100 μg/kg). Markers of oxidative stress, inflammatory cytokines, and BBB integrity were then evaluated. In vitro, bEnd.3 cells were treated with HIV-1 Tat and Kp-10, and endothelial permeability, Claudin-5 expression, and RhoA/ROCK signaling were assessed. HIV-1 Tat increased oxidative stress in the cortical tissue of mice, as evidenced by elevated malondialdehyde (MDA) and reduced levels of catalase (CAT) activity, glutathione peroxidase (GSH-Px) activity, and total antioxidant capacity (T-AOC). These effects were attenuated by Kp-10 administration. Additionally, Kp-10 suppressed the expression of pro-inflammatory cytokines, including interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-α), in response to HIV-1 Tat. Notably, Kp-10 mitigated HIV-1 Tat-induced BBB dysfunction by upregulating Claudin-5 expression in the cortical tissue of mice. In vitro, bEnd.3 cells were treated with HIV-1 Tat in the presence of Kp-10 at various concentrations. Our results demonstrated that Kp-10 prevented HIV-1 Tat-induced increases in trans-endothelial permeability and reductions in transepithelial electrical resistance (TEER) by upregulating Claudin-5 expression. Furthermore, Kp-10 inhibited the activation of the RhoA/Rho-associated protein kinase (RhoA/ROCK) signaling pathway in bEnd.3 cells. Overexpression of the RhoA-GTP Q63L mutant abolished the protective effects of Kp-10, suggesting that these effects are mediated through the RhoA/ROCK axis. These findings suggest that Kp-10 might be a potential therapeutic agent for HIV-associated neurocognitive disorders (HAND).