Prolidase Stimulates Proliferation and Migration through Activation of the PI3K/Akt/mTOR Signaling Pathway in Human Keratinocytes

• Published in: International journal of molecular sciences Vol. 21; no. 23; p. 9243
• Main Authors: Misiura, Magdalena, Baszanowska, Weronika, Ościłowska, Ilona, Pałka, Jerzy, Miltyk, Wojciech
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 03.12.2020; MDPI
• Subjects: 1-Phosphatidylinositol 3-kinase; AKT protein; Biosynthesis; Cell adhesion & migration; Cell growth; Cell Line, Tumor; Cell Movement - drug effects; Cell proliferation; Cell Proliferation - drug effects; Collagen; Colorimetry; Dipeptidases - metabolism; Dipeptidases - pharmacology; EGFR; Enzymes; Epidermal growth factor; Epidermal growth factor receptors; ErbB Receptors - metabolism; Growth factors; Humans; Immunoblotting; Insulin; Insulin-like growth factor I; Integrin beta1 - genetics; Integrin beta1 - metabolism; Keratinocytes; Keratinocytes - drug effects; Keratinocytes - metabolism; Kinases; Ligands; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Models, Biological; PEPD; Phosphatidylinositol 3-Kinases - metabolism; Phosphorylation; Prolidase; Proline; Protein Binding; Proteins; Proto-Oncogene Proteins c-akt - metabolism; Receptor, IGF Type 1 - genetics; Receptor, IGF Type 1 - metabolism; Signal transduction; Signal Transduction - drug effects; Tissue engineering; TOR protein; TOR Serine-Threonine Kinases - metabolism; Transforming growth factor-b1; Wound healing; wound healing; keratinocytes; PEPD; prolidase; EGFR
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21239243

Recent reports have indicated prolidase (PEPD) as a ligand of the epidermal growth factor receptor (EGFR). Since this receptor is involved in the promotion of cell proliferation, growth, and migration, we aimed to investigate whether prolidase may participate in wound healing in vitro. All experiments were performed in prolidase-treated human keratinocytes assessing cell vitality, proliferation, and migration. The expression of downstream signaling proteins induced by EGFR, insulin-like growth factor 1 (IGF-1), transforming growth factor β (TGF-β ), and β -integrin receptors were evaluated by Western immunoblotting and immunocytochemical staining. To determine collagen biosynthesis and prolidase activity radiometric and colorimetric methods were used, respectively. Proline content was determined by applying the liquid chromatography coupled with mass spectrometry. We found that prolidase promoted the proliferation and migration of keratinocytes through stimulation of EGFR-downstream signaling pathways in which the PI3K/Akt/mTOR axis was involved. Moreover, PEPD upregulated the expression of β -integrin and IGF-1 receptors and their downstream proteins. Proline concentration and collagen biosynthesis were increased in HaCaT cells under prolidase treatment. Since extracellular prolidase as a ligand of EGFR induced cell growth, migration, and collagen biosynthesis in keratinocytes, it may represent a potential therapeutic approach for the treatment of skin wounds.