Tri-Combination Antiretroviral Therapy Induces Dose- and Time-Dependent Disruption of Intestinal Epithelial Barrier...

Antiretroviral therapy (ART) is essential for controlling human immunodeficiency virus (HIV) infection, requiring strict daily adherence for lifelong viral suppression. However, this continuous oral dosing results in persistent exposure of the gastrointestinal tract (GIT), raising the need to investigate the effects of TC-ART (Tri-combinationL: Abacavir, Dolutegravir, Lamivudine-ART) on epithelial integrity, barrier recovery mechanisms, and surface barrier architecture. TC-ART exposure (125 µM to 4000 µM) showed marked alterations in transepithelial resistance, permeability, and wound-healing abilities even at sub-cytotoxic doses. The dose exposure range at the mid-dose level showed the highest transcriptional activity, characterized by a downregulation of junctional genes [claudins (CLDNs), desmogleins (DSGs), and junctional plakoglobin (JUP)] and signaling mediators [the signal transducer and activator of transcription 3 (STAT3), mitogen-activated protein kinase 1 and 3 (MAPK1/3), and catenin beta 1 (CTNNB1)], along with reduced IL-9 expression that is linked to mucin loss. These transcriptional changes were consistent with structural findings, including partial transepithelial electrical resistance (TEER) recovery followed by a decline, delayed wound closure, and waning of the apical mucin layer in a dose-dependent manner. However, several cytokines, like IL-2 and IL-6, showed increased secretion despite lower transcriptional levels, suggesting alternative regulatory control during early stress responses. Together, these results support that TC-ART exposure alters epithelial responses in a way that may transition from early adaptation to signs of impaired recovery, leading to a gradual decline in mucosal barrier function. Such concentration- and time-dependent epithelial stress may contribute to gastrointestinal disturbances observed in treated HIV populations, emphasizing the need for incorporating intestinal epithelial health endpoints in drug safety evaluations.