Low-power laser alters mRNA levels from DNA repair genes in acute lung injury induced by sepsis in Wistar rats

Does photobiomodulation alter mitochondrial dynamics?

Mitochondrial dysfunction is one of the leading causes of disease development. Dysfunctional mitochondria limit energy production, increase reactive oxygen species generation, and trigger apoptotic signals. Photobiomodulation is a noninvasive, nonthermal technique involving the application of monochromatic light with low energy density, inducing non-thermal photochemical effects at the cellular level, and it has been used due to its therapeutic potential. This review focuses on the mitochondrial dynamic's role in various diseases, evaluating the possible therapeutic role of low-power lasers (LPL) and light-emitting diodes (LED). Studies increasingly support that mitochondrial dysfunction is correlated with severe neurodegenerative diseases such as Parkinson's, Huntington's, Alzheimer's, and Charcot-Marie-Tooth diseases. Furthermore, a disturbance in mitofusin activity is also associated with metabolic disorders, including obesity and type 2 diabetes. The effects of PBM on mitochondrial dynamics have been observed in cells using a human fibroblast cell line and in vivo models of brain injury, diabetes, spinal cord injury, Alzheimer's disease, and skin injury. Thus, new therapies aiming to improve mitochondrial dynamics are clinically relevant. Several studies have demonstrated that LPL and LED can be important therapies to improve health conditions when there is dysfunction in mitochondrial dynamics.

Effects of low‑power red laser and blue LED on mRNA levels from DNA repair genes in human breast cancer cells

Photobiomodulation (PBM) induced by non-ionizing radiations emitted from low-power lasers and light-emitting diodes (LEDs) has been used for various therapeutic purposes due to its molecular, cellular, and systemic effects. At the molecular level, experimental data have suggested that PBM modulates base excision repair (BER), which is responsible for restoring DNA damage. There is a relationship between the misfunction of the BER DNA repair pathway and the development of tumors, including breast cancer. However, the effects of PBM on cancer cells have been controversial. Breast cancer (BC) is the main public health problem in the world and is the most diagnosed type of cancer among women worldwide. Therefore, the evaluation of new strategies, such as PBM, could increase knowledge about BC and improve therapies against BC. Thus, this work aims to evaluate the effects of low-power red laser (658 nm) and blue LED (470 nm) on the mRNA levels from BER genes in human breast cancer cells. MCF-7 and MDA-MB-231 cells were irradiated with a low-power red laser (69 J cm-2, 0.77 W cm-2) and blue LED (482 J cm-2, 5.35 W cm-2), alone or in combination, and the relative mRNA levels of the APTX, PolB, and PCNA genes were assessed by reverse transcription-quantitative polymerase chain reaction. The results suggested that exposure to low-power red laser and blue LED decreased the mRNA levels from APTX, PolB, and PCNA genes in human breast cancer cells. Our research shows that photobiomodulation induced by low-power red laser and blue LED decreases the mRNA levels of repair genes from the base excision repair pathway in MCF-7 and MDA-MB-231 cells.

Photobiomodulation with 630-nm LED Inhibits M1 Macrophage Polarization via STAT1 Pathway Against Sepsis-Induced Acute Lung Injury

Background: Sepsis-induced acute lung injury (ALI) is a clinical syndrome characterized by excessive uncontrolled inflammation. Photobiomodulation such as light-emitting diode (LED) irradiation has been used to attenuate inflammatory disease. Objective: The protective effect of 630 nm LED irradiation on sepsis-induced ALI remains unknown. The purpose of this study was to investigate the role of 630 nm LED irradiation in sepsis-induced ALI and its underlying mechanism. Methods and results: C57BL/6 mice were performed cecal ligation and puncture (CLP) for 12 h to generate experimental sepsis models. Histopathology analysis showed that alveolar injury, inflammatory cells infiltration, and hemorrhage were suppressed in CLP mice after 630 nm LED irradiation. The ratio of wet/dry weigh of lung tissue was significantly inhibited by irradiation. The number of leukocytes was reduced in bronchoalveolar lavage fluid. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) results and enzyme-linked immunosorbent assay showed that 630 nm LED irradiation significantly inhibited the mRNA and protein levels of M1 macrophage-related genes in the lung of CLP-induced septic mice. Meanwhile, LED irradiation significantly inhibited signal transducer and activator of transcription 1 (STAT1) phosphorylation in the lung of septic mice. In vitro experiments showed that 630 nm LED irradiation significantly inhibited M1 genes mRNA and protein expression in THP-1-derived M1 macrophages without affecting the cell viability. LED irradiation also significantly inhibited the level of STAT1 phosphorylation in THP-1-derived M1 macrophages. Conclusions: We concluded that 630 nm LED is promising as a treatment against ALI through inhibiting M1 macrophage polarization, which is associated with the downregulation of STAT1 phosphorylation.

Low-power infrared laser modulates mRNA levels from genes of base excision repair and genomic stabilization in heart tissue from an experimental model of acute lung injury

The aim of this study was to evaluate photobiomodulation effects on mRNA relative levels from genes of base excision repair and genomic stabilization in heart tissue from an experimental model of acute lung injury by sepsis. For experimental procedure, animals were randomly assigned to six main groups: (1) control group was animals treated with intraperitoneal saline solution; (2) LASER-10 was animals treated with intraperitoneal saline solution and exposed to an infrared laser at 10 J cm^-2; (3) LASER-20 was animals treated with intraperitoneal saline solution and exposed to an infrared laser at 20 J cm^-2; (4) acute lung injury (ALI) was animals treated with intraperitoneal LPS (10 mg kg^-1); (5) ALI-LASER10 was animals treated with intraperitoneal LPS (10 mg kg^-1) and, after 4 h, exposed to an infrared laser at 10 J cm^-2 and (6) ALI-LASER20 was animals treated with intraperitoneal LPS (10 mg kg^-1) and, after 4 h, exposed to an infrared laser at 20 J cm^-2. Irradiation was performed only once and animal euthanasias for analysis of mRNA relative levels by RT-qPCR. Our results showed that there was a reduction of mRNA relative levels from ATM gene and an increase of mRNA relative levels from P53 gene in the heart of animals with ALI when compared to the control group. In addition, there was an increase of mRNA relative levels from OGG1 and APE1 gene in hearts from animals with ALI when compared to the control group. After irradiation, an increase of mRNA relative levels from ATM and OGG1 gene was observed at 20 J cm^-2. In conclusion, low-power laser modulates the mRNA relative levels from genes of base excision repair and genomic stabilization in the experimental model of acute lung injury evaluated.

Effect of low-level laser therapy on the inflammatory response in an experimental model of ventilator-induced lung injury

The effect of low-level laser therapy (LLLT) on an experimental model of ventilator-induced lung injury (VILI) was evaluated in this study. 24 adult Wistar rats were randomized into four groups: protective mechanical ventilation (PMV), PMV + laser, VILI and VILI + laser. The animals of the PMV and VILI groups were ventilated with tidal volumes of 6 and 35 ml kg⁻¹, respectively, for 90 minutes. After the first 60 minutes of ventilation, the animals in the laser groups were irradiated (808 nm, 100 mW power density, 20 J cm⁻² energy density, continuous emission mode, and exposure time of 5 s) and after 30 minutes of irradiation, the animals were euthanized. Lung samples were removed for morphological analysis, bronchoalveolar lavage (BAL) and real time quantitative polynucleotide chain reaction (RT-qPCR). The VILI group showed a greater acute lung injury (ALI) score with an increase in neutrophil infiltration, higher neutrophil count in the BAL fluid and greater cytokine mRNA expression compared to the PMV groups (p < 0.05). The VILI ± laser group when compared to the VILI group showed a lower ALI score (0.35 ± 0.08 vs. 0.54 ± 0.13, p < 0.05), alveolar neutrophil infiltration (7.00 ± 5.73 vs. 21.50 ± 9.52, p < 0.05), total cell count (1.90 ± 0.71 vs. 4.09 ± 0.96 × 10⁵, p < 0.05) and neutrophil count in the BAL fluid (0.60 ± 0.37 vs. 2.28 ± 0.48 × 10⁵, p < 0.05). Moreover, LLLT induced a decrease in pro-inflammatory and an increase of anti-inflammatory mRNA levels compared to the VILI group (p < 0.05). In conclusion, LLLT was found to reduce the inflammatory response in an experimental model of VILI.

Protective effects of P2X7R antagonist in sepsis-induced acute lung injury in mice via regulation of circ_0001679 and circ_0001212 and downstream Pln, Cdh2, and Nprl3 expression

BACKGROUND

Sepsis induces pulmonary P2X₇ receptor (P2X₇ R) expression and P2X₇ R-knockout reduced lung inflammation in mice. The present study investigated the expression of circular RNA (circRNA) and mRNA in sepsis-induced acute lung injury (ALI) treated with a P2X₇ R antagonist.

METHODS

Sepsis was induced by tracheal administration of lipopolysaccharide (LPS), and the mice were then divided into two groups: without [sepsis + dimethyl sulfoxide (DMSO)] or with P2X₇ R antagonist treatment (sepsis + P2X₇ A). Sham mice were administrated sterile normal saline. Serum levels of interleukin (IL)-1β and tumor necrosis factor (TNF)-α, pathological changes, cell apoptosis and P2X₇ R expression in lung were assessed, followed by RNA sequencing (RNA-seq) and bioinformatics analyses. A quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) was used to validate circRNAs and mRNAs.

RESULTS

Compared to the sham group, LPS-induced sepsis produced obvious pathological changes in lung tissue, as well as increased apoptotic lung cells, serum TNF-α and IL-1β levels, and P2X₇ R expression; P2X₇ R antagonism significantly ameliorated these changes. RNA-seq identified many dysregulated circRNAs and mRNAs during sepsis, whereas this changed with P2X₇ R antagonism. RT-qPCR confirmed that Mus musculus (mmu)_circ_0001679, mmu_circ_0001212, phospholamban (Pln), cadherin-2 (Cdh2) and nitrogen permease regulator 3-like (Nprl3) expression were significantly increased in the sepsis + DMSO group compared to that in the sham group but were decreased in the sepsis + P2X₇ A group compared to that in the sepsis + DMSO group. The circRNA-microRNA-mRNA coexpression network indicated that mmu_circ_0001679 may regulate Nprl3 and that mmu_circ_0001212 may similarly regulate Pln, Cdh2 and Nprl3 as a competing endogenous RNA.

CONCLUSIONS

P2X₇ R antagonism attenuates sepsis-induced ALI by inhibiting dysregulated expression of circRNA (circ_0001679, circ_0001212) and mRNA (Pln, Cdh2 and Nprl3).

DNA repair and genomic stability in lungs affected by acute injury

Acute pulmonary injury, or acute respiratory distress syndrome, has a high incidence in elderly individuals and high mortality in its most severe degree, becoming a challenge to public health due to pathophysiological complications and increased economic burden. Acute pulmonary injury can develop from sepsis, septic shock, and pancreatitis causing reduction of alveolar airspace due to hyperinflammatory response. Oxidative stress acts directly on the maintenance of inflammation, resulting in tissue injury, as well as inducing DNA damages. Once the DNA is damaged, enzymatic DNA repair mechanisms act on lesions in order to maintain genomic stability and, consequently, contribute to cell viability and homeostasis. Although palliative treatment based on mechanical ventilation and antibiotic using have a kind of efficacy, therapies based on modulation of DNA repair and genomic stability could be effective for improving repair and recovery of lung tissue in patients with acute pulmonary injury.