Antimicrobial Peptides and Biomarkers Induced by Ultraviolet Irradiation Have the Potential to Reduce Endodontic Inflammation and Facilitate Tissue Healing

Abstract

Background: Ultraviolet (UV) irradiation can modulate host immune responses and this approach is a novel application for treating endodontic infections and inflammation in root canals. Methods: A dataset of UV-induced molecules was compiled from a literature search. A subset of this dataset was used to calculate expression log2 ratios of endodontic tissue molecules from HEPM cells and gingival fibroblasts after 255, 405, and 255/405 nm UV irradiation. Both datasets were analyzed using ingenuity pathway analysis (IPA, Qiagen, Germantown, MD, USA). Statistical significance was calculated using Fisher’s exact test and z-scores were calculated for IPA comparison analysis. Results: The dataset of 32 UV-induced molecules contained 9 antimicrobial peptides, 10 cytokines, 6 growth factors, 3 enzymes, 2 transmembrane receptors, and 2 transcription regulators. These molecules were in the IPA canonical pathway annotations for the wound healing signaling pathway (9/32, p = 3.22 × 10−11) and communication between immune cells (6/32, p = 8.74 × 10−11). In the IPA disease and function annotations, the 32 molecules were associated with an antimicrobial response, cell-to-cell signaling and interaction, cellular movement, hematological system development and function, immune cell trafficking, and inflammatory response. In IPA comparison analysis of the 13 molecules, the predicted activation or inhibition of pathways depended upon the cell type exposed, the wavelength of the UV irradiation used, and the time after exposure. Conclusions: UV irradiation activates and inhibits cellular pathways and immune functions. These results suggested that UV irradiation can activate innate and adaptive immune responses, which may supplement endodontic procedures to reduce infection, inflammation, and pain and assist tissues to heal.

Livin is protective in UVB‐induced skin photodamage by regulating keratinocyte activation and inflammatory responses

“…Furthermore, the analysis of protein interactions indicated that Livin expression influenced the expression of keratins (Figure 5A). Keratin 14 and 17 are known to be elevated in UVB‐induced skin photodamage, impacting epidermal barrier function 16,17 . In this study, UVB exposure at 250 mJ/cm 2 did not result in elevations in keratin 17 and keratin 14 levels in Livin fl/fl mice.…”

“…Keratin 14 and 17 are known to be elevated in UVB-induced skin photodamage, impacting epidermal barrier function. 16,17 In this study, UVB exposure at 250 mJ/cm 2 did not result in elevations in keratin 17 and keratin 14 levels in Livin fl/fl mice. In contrast, these levels were significantly elevated in Livin ΔKC mice (Figure 5B).…”

“…However, the study of the inflammatory response in UVB-induced damage is not complete. After analysing the RNA-seq data, we discovered that Livin expression influenced the release of antimicrobial peptides such as S100A3, S100A7, and BD1 from KCs, which have been demonstrated to play important roles in many inflammatory skin diseases and could be increased following UVB exposure [16,17]. UVB exposure at 250 mJ/cm 2 did not induce significant releases of S100A3, S100A7 or BD1 in Livin fl/fl mice.…”

The Editorial Position on ‘Recent Advances in Multifunctional Antimicrobial Peptides as Preclinical Therapeutic Studies and Clinical Future Applications’

“…Many of these molecules are related to the wound-healing signaling pathway and communication between immune cells and antimicrobial response. They concluded that, also via the UV irradiation technique, AMPs production requires part of the activate innate immune response with a final aim to reduce infection but also assist tissue healing [27].…”