Exposure to b-LED Light While Exerting Antimicrobial Activity on Gram-Negative and -Positive Bacteria Promotes Transient EMT-like Changes and Growth Arrest in Keratinocytes

• Published in: International journal of molecular sciences Vol. 23; no. 3; p. 1896
• Main Authors: Terri, Michela, Mancianti, Nicoletta, Trionfetti, Flavia, Casciaro, Bruno, de Turris, Valeria, Raponi, Giammarco, Bontempi, Giulio, Montaldo, Claudia, Domenici, Alessandro, Menè, Paolo, Mangoni, Maria Luisa, Strippoli, Raffaele
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 08.02.2022; MDPI
• Subjects: Antigens, CD - metabolism; Antiinfectives and antibacterials; Antimicrobial activity; Antimicrobial agents; Apoptosis; b-led light; Bacteria; Bactericidal activity; Cadherins - metabolism; Catheters; Cell cycle; Cell Cycle Checkpoints - radiation effects; Cell growth; Cell Proliferation; Cyclin D1; Cyclin D1 - metabolism; Cyclin-Dependent Kinase Inhibitor p21 - metabolism; Cytotoxicity; Down Syndrome; Drug resistance; E-cadherin; EMT; Epithelial-Mesenchymal Transition - radiation effects; Exposure; Gene Expression Regulation - drug effects; genotoxic damage; Genotoxicity; Gram-negative bacteria; Gram-positive bacteria; HaCaT Cells; Histone H2A; Humans; Keratinocytes; Keratinocytes - cytology; Keratinocytes - metabolism; Keratinocytes - radiation effects; Light - adverse effects; Light emitting diodes; Mesenchyme; Microbial Viability - radiation effects; Microbicides; Microorganisms; Nosocomial infections; Peritoneal dialysis; Phenotypes; Phosphors; Pseudomonas aeruginosa; Pseudomonas aeruginosa - growth & development; Pseudomonas aeruginosa - radiation effects; Radiation; skin infections; Snail Family Transcription Factors - metabolism; Staphylococcus aureus - growth & development; Staphylococcus aureus - radiation effects; Staphylococcus infections; United States > US; genotoxic damage; EMT; skin infections; b-led light
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms23031896

While blue LED (b-LED) light is increasingly being studied for its cytotoxic activity towards bacteria in therapy of skin-related infections, its effects on eukaryotic cells plasticity are less well characterized. Moreover, since different protocols are often used, comparing the effect of b-LED towards both microorganisms and epithelial surfaces may be difficult. The aim of this study was to analyze, in the same experimental setting, both the bactericidal activity and the effects on human keratinocytes. Exposure to b-LED induced an intense cytocidal activity against Gram-positive (i.e, ) and Gram-negative (i.e., ) bacteria associated with catheter-related infections. Treatment with b-LED of a human keratinocyte cell line induced a transient cell cycle arrest. At the molecular level, exposure to b-LED induced a transient downregulation of Cyclin D1 and an upregulation of p21, but not signs of apoptosis. Interestingly, a transient induction of phosphor-histone γ-H2Ax, which is associated with genotoxic damages, was observed. At the same time, keratinocytes underwent a transient epithelial to mesenchymal transition (EMT)-like phenotype, characterized by E-cadherin downregulation and SNAIL/SLUG induction. As a functional readout of EMT induction, a scratch assay was performed. Surprisingly, b-LED treatment provoked a delay in the scratch closure. In conclusion, we demonstrated that b-LED microbicidal activity is associated with complex responses in keratinocytes that certainly deserve further analysis.