# Photodynamic Therapy Modulates pri-miRNA Expression in C. albicans-Infected HEK-293 Cells: An In Vitro Study

## TL;DR

This study shows that photodynamic therapy can reduce the expression of specific pri-miRNAs in cells infected with Candida albicans, suggesting it may help monitor and treat fungal infections.

## Contribution

The study introduces the use of pri-miRNA expression as a biomarker for evaluating photodynamic therapy in Candida-infected cells.

## Key findings

- C. albicans infection increased pri-miRNA 146a and 155 expression by 2- to 3.5-fold.
- PDT treatment restored pri-miRNA levels to baseline after infection.
- Pri-miRNAs 146a/155 may serve as biomarkers for monitoring PDT effectiveness.

## Abstract

Oral infections caused by Candida spp. represent a major health concern due to the increasing resistance of these fungi to conventional antifungal agents. Photodynamic therapy (PDT) is a treatment based on the use of light at a specific wavelength that activates a photosensitizer (PS) in the presence of oxygen. The activated PS selectively binds to infected cells and induces apoptosis through the generation of reactive oxygen species (ROS). Previous biomolecular studies on Candida albicans have demonstrated that its infection triggers characteristic molecular signals, such as miRNA-146a and miRNA-155, which serve as inflammatory markers. This in vitro study aimed to evaluate the impact of PDT on the expression of their primary transcripts (pri-miRNAs) in a cell culture model of C. albicans infection. Human embryonic kidney (HEK-293) cells were infected with a multidrug-resistant strain of C. albicans (CA97) and subsequently exposed to curcumin-based PDT activated by blue light (470 nm). The expression of pri-miRNAs 146a and 155 was assessed before and after PDT treatment for each experimental group. The expression levels of pri-miRNAs increased approximately 2- to 3.5-fold following C. albicans infection but returned to baseline values after PDT treatment. The evaluation of pri-miRNAs 146a/155 may serve as a valuable research tool for monitoring early inflammatory responses induced by Candida infection, as well as a sensitive biomarker for assessing the effectiveness of photodynamic therapy in an in vitro cell culture model.