Selective down-regulation of aquaporin-1 in salivary glands in primary Sjögren's syndrome.

Salivary and lacrimal gland secretions are reduced in primary Sjögren's syndrome (pSS). Aquaporins (AQPs) are involved in transmembrane water transport, and different isoforms show specific cellular and subcellular distributions in salivary and lacrimal glands. Changes in expression of AQP molecules have therefore been suggested to contribute to the glandular dysfunction in pSS.

Anti-La/SSB antibodies transported across the placenta bind apoptotic cells in fetal organs targeted in neonatal lupus.

Objective: To determine whether La and/or Ro epitopes on apoptotic cells in fetal organs that are targeted in neonatal lupus syndrome (NLS) are accessible for binding by autoantibodies in vivo, we traced the fate of transplacental autoantibodies in a murine passive transfer model.

Methods: Pregnant mice at day 15 of gestation (E15) were injected intraperitoneally with human anti-Ro/La-positive sera or control sera, and transplacental transfer of human autoantibodies was tested by enzyme-linked immunosorbent assay with recombinant antigens. Multiple cryostat sections at the level of the heart of E17 fetuses were visualized simultaneously for human IgG binding and apoptosis (TUNEL) under confocal microscopy.

Up-regulation of M3-muscarinic receptors in labial salivary gland acini in primary Sjögren's syndrome.

M3-muscarinic receptors (M3R) mediate parasympathetic cholinergic neurotransmission to salivary and lacrimal glands, and autoantibodies to these receptors have been implicated in sicca symptoms and autonomic dysfunction in Sjögren's syndrome. We have investigated the expression of M3R in paraffin-embedded labial salivary glands (LSG) from seven patients with primary Sjögren's syndrome (pSS) and five healthy controls using high-resolution confocal microscopy and an affinity-purified goat polyclonal antibody raised against the COOH-terminal sequence of the human M3R. Immunolocalization of M3R was similar in control and pSS glands, with punctate staining of M3R in the basal membrane of acinar cells and in the luminal and abluminal membrane of myoepithelial cells.

Subcellular redistribution of la/SSB autoantigen during physiologic apoptosis in the fetal mouse heart and conduction system: a clue to the pathogenesis of congenital heart block.

Objective: In isolated congenital heart block, the mechanism by which maternal autoantibodies target the intracellular components of the Ro/La RNP complex is unclear. Previous studies have demonstrated that cultured fetal cardiac myocytes rendered apoptotic bind antibodies to 48-kd La/SSB. This study further investigated the subcellular distribution of the La antigen during apoptosis in the fetal mouse heart and conduction system.