Akt Signaling Pathway Is Activated in the Minor Salivary Glands of Patients with Primary Sjögren's Syndrome

• Published in: International journal of molecular sciences Vol. 22; no. 24; p. 13441
• Main Authors: Stergiou, Ioanna E, Chatzis, Loukas, Papanikolaou, Asimina, Giannouli, Stavroula, Tzioufas, Athanasios G, Voulgarelis, Michael, Kapsogeorgou, Efstathia K
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 14.12.2021; MDPI
• Subjects: Adult; Aged; AKT protein; AKT signaling pathway; Apoptosis; Arthritis; Autoimmune diseases; Autoimmunity; Biopsy; Cyclin-dependent kinases; Cytokines; Disease; Exocrine glands; Female; FOXO1 protein; Gene expression; Growth factors; Humans; infiltrating mononuclear cells; Kinases; Lacrimal gland; Leukocytes (mononuclear); Lymphoma; Male; Middle Aged; minor salivary glands; non-Hodgkin lymphoma; Pathogenesis; Phosphorylation; Proline; Protein-serine/threonine kinase; Proteins; Proto-Oncogene Proteins c-akt - metabolism; Salivary gland; salivary gland epithelial cells; Salivary glands; Salivary Glands, Minor - enzymology; Salivary Glands, Minor - pathology; Signal Transduction; Sjogren's syndrome; Sjogren's Syndrome - enzymology; Sjogren's Syndrome - pathology; Sjögren’s syndrome; Therapeutic targets; Transcription factors; Tumorigenesis; Sjögren’s syndrome; infiltrating mononuclear cells; non-Hodgkin lymphoma; AKT signaling pathway; minor salivary glands; salivary gland epithelial cells
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms222413441

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy of mainly the salivary and lacrimal glands associated with high prevalence of lymphoma. Akt is a phosphoinositide-dependent serine/threonine kinase, controlling numerous pathological processes, including oncogenesis and autoimmunity. Herein, we sought to examine its implication in pSS pathogenesis and related lymphomagenesis. The expression of the entire and activated forms of Akt (partially and fully activated: phosphorylated at threonine-308 (T308) and serine-473 (S473), respectively), and two of its substrates, the proline-rich Akt-substrate of 40 kDa (PRAS40) and FoxO1 transcription factor has been immunohistochemically examined in minor salivary glands (MSG) of pSS patients ( = 29; including 9 with pSS-associated lymphoma) and sicca-complaining controls (sicca-controls; = 10). The entire and phosphorylated Akt, PRAS40, and FoxO1 molecules were strongly, uniformly expressed in the MSG epithelia and infiltrating mononuclear cells of pSS patients, but not sicca-controls. Morphometric analysis revealed that the staining intensity of the fully activated phospho-Akt-S473 in pSS patients (with or without lymphoma) was significantly higher than sicca-controls. Akt pathway activation was independent from the extent or proximity of infiltrates, as well as other disease features, including lymphoma. Our findings support that the Akt pathway is specifically activated in MSGs of pSS patients, revealing novel therapeutic targets.