AQP1 Corrects Acinar Cells’ Secretion Deficits in Sjögren's Disease

Introduction Sjögren's disease (SjD) is a systemic autoimmune disease characterized by dry mouth, dry eyes, and profound fatigue. Preclinical studies suggest that AQP1 gene expression in salivary glands corrects salivary hypofunction in preclinical and clinical studies of radiation‐induced xerostomia and improves salivary and lacrimal function in SjD mouse models. Subjects and Methods To evaluate its therapeutic potential, we tested AQP1 gene therapy using labial salivary gland (LSG) biopsies from patients with SjD, non‐SjD, and healthy volunteer glands (HV). Results Ex vivo cultures of LSG lobules were viable, responsive to stimulation, and transducible with an AAV2 vector encoding AQP1. AQP1 expression increased fluid secretion in most samples, with recovery reaching up to 80% of healthy volunteer levels. Baseline transcriptomic analysis identifies 94 genes that correlated with treatment response, with inflammatory and epithelial signature correlating with success and fibrotic signatures with non‐response. Histological evaluation confirmed greater fibrosis in non‐responding samples. Thus, treatment effects were functionally significant but transcriptionally minimal indicating targeted therapeutic action without altering homeostatic transcription. Conclusion These findings demonstrate that AAV2‐AQP1 expression enhances fluid secretion in human LSGs and highlight fibrosis‐associated loss of glandular parenchyma as a major barrier to therapeutic efficacy.