Extracellular vesicles mediated proinflammatory macrophage phenotype induced by radiotherapy in cervical cancer.

BACKGROUND: Radiotherapy is a highly effective treatment for cervical cancer. Recent studies focused on the radiotherapy induced anti-tumor immunity. Whether tumor-derived extracellular vesicles (EVs) play roles in radiotherapy induced tumor associated macrophage (TAM) polarization remains unclear. MATERIALS AND METHODS: This study analysed the phenotype of macrophages in cancer tissue and peripheral blood of cervical cancer patients using flow cytometry analysis. The role of EVs from plasma of post-irradiated patients on M2-like transformed macrophages was assessed. The M1- and M2-like macrophages were assessed by expression of cell surface markers (CCR7, CD163) and intracellular cytokines (IL-10, TNFα and iNOS). The capacity of phagocytosis was assessed by PD-1 expression and phagocytosis of pHrodo Red E. coli bioparticles. RESULTS: Our results demonstrated that radiotherapy of cervical cancer induced an increase in the number of TAMs and a change in their subtype from the M2-like to the M1-like phenotype (increased expression of CCR7 and decreased expression of CD163). The EVs from plasma of post-irradiated patients facilitated the M2-like to the M1-like phenotype transition (increased expression of CCR7, TNFα and iNOS, and decreased expression of CD163 and IL-10) and increased capacity of phagocytosis (decreased PD-1 expression and increased phagocytosis of pHrodo Red E. coli bioparticles). CONCLUSIONS: Our data demonstrated that irradiation in cervical cancer patients facilitated a proinflammatory macrophage phenotype which could eventually able to mediate anti-tumor immune responses. Our findings highlight the importance of EV in the crosstalk of tumor cells and TAM upon irradiation, which potentially leading to an increased inflammatory response to cancer lesions.

Anti-Inflammatory and Healing Effects of Pulsed Ultrasound Therapy on Fibroblasts.

OBJECTIVE: The aim of this study was to analyze the effects of low-intensity pulsed ultrasound therapy under different pulse regimes on cultures of semiconfluent L929 fibroblasts, evaluating cell viability, anatomical structural alterations, modulation of vascular endothelial growth factor, interleukin 6, collagen type 1 alpha 1, collagen type 1 alpha 2, and fibroblast growth factor 7, as well as the amount of inflammatory mediators interleukin 2, interleukin 4, interleukin 6, interferon γ, tumor necrosis factor, interleukin 17A, and interleukin 10 at 24, 48, and 72 hrs. DESIGN: The design was experimental study. METHODS: The treatments consisted of 0.2 W/cm doses at a frequency of 1 MHz, with a pulse rate of 10% and 20%. Viability was assessed by the MTT assay (3-(4,5-dimethylthiazole)-2,5-diphenyltetrazolium bromide), gene expression by real-time quantitative polymerase chain reaction, and cytokine quantification by flow cytometry. RESULTS: At 48 hrs, ultrasound enhanced cell viability and affected interleukin 6 cytokine production, vascular endothelial growth factor, interleukin 6, type 1 alpha 1 and alpha 2 collagens, and fibroblast growth factor 7 gene modulation. CONCLUSIONS: Low-intensity pulsed ultrasound therapy had a biostimulatory effect on semiconfluent in vitro L929 fibroblast cells, where the group with a dose of 0.2 W/cm-10% (G2) presented higher responses, in all the analyzed aspects, toward the dose pulsed to 20%, confirming its therapeutic properties related to the initial phases of tissue healing.

Therapeutic ultrasound attenuates DSS-induced colitis through the cholinergic anti-inflammatory pathway.

BACKGROUND: Ulcerative Colitis (UC) is an Inflammatory Bowel Disease (IBD) characterized by uncontrolled immune response, diarrhoea, weight loss and bloody stools, where sustained remission is not currently achievable. Dextran Sulphate Sodium (DSS)-induced colitis is an animal model that closely mimics human UC. Ultrasound (US) has been shown to prevent experimental acute kidney injury through vagus nerve (VN) stimulation and activation of the cholinergic anti-inflammatory pathway (CAIP). Since IBD patients may present dysfunctional VN activity, our aim was to determine the effects of therapeutic ultrasound (TUS) in DSS-induced colitis. METHODS: Acute colitis was induced by 2% DSS in drinking water for 7 days and TUS was administered to the abdominal area for 7 min/day from days 4-10. Clinical symptoms were analysed, and biological samples were collected for proteomics, macroscopic and microscopic analysis, flow cytometry and immunohistochemistry. FINDINGS: TUS attenuated colitis by reducing clinical scores, colon shortening and histological damage, inducing proteomic tolerogenic response in the gut during the injury phase and early recovery of experimental colitis. TUS did not improve clinical and pathological outcomes in splenectomised mice, while α7nAChR (α7 nicotinic acetylcholine receptor - indicator of CAIP involvement) knockout animals presented with disease worsening. Increased levels of colonic F4/80+α7nAChR+ macrophages in wild type mice suggest CAIP activation. INTERPRETATION: These results indicate TUS improved DSS-induced colitis through stimulation of the splenic nerve along with possible contribution by VN with CAIP activation. FUND: Intramural Research Programs of the Clinical Centre, the National Institute of Biomedical Imaging and Bioengineering at the NIH and CAPES/Brazil.

Phenylephrine Alleviates 131I Radiation Damage in Submandibular Gland Through Maintaining Mitochondrial Homeostasis.

PURPOSE: The impairment of the salivary glands is a permanent side effect of 131I ablation therapy for patients with differentiated thyroid cancer. Effective and safe treatments for protecting the salivary glands against 131I are currently not available. Mitochondria are susceptible to ionizing radiation, but alterations after 131I exposure are unknown. Here, we investigated the mechanisms of 131I damage in submandibular glands (SMGs) and evaluated the cytoprotective effect of phenylephrine (PE) against mitochondrial radiation damage. METHODS AND MATERIALS: Rats were randomly divided into 4 groups: control, PE alone, 131I alone, and 131I with PE pretreatment. The mitochondrial structure of SMGs was observed under transmission electron microscopy. Apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Cytochrome c, cleaved-caspase 3, SIRT1, NAMPT, and PGC-1α protein levels were determined with Western blot and immunohistochemistry. Levels of mitochondrial membrane potential, nicotinamide adenine dinucleotide (NAD), and adenosine triphosphate (ATP) were measured with relevant kits. RESULTS: After exposing rat SMGs to 131I, the mitochondrial membrane structures were destroyed, the mitochondrial membrane potential decreased, the release of cytochrome c increased, and cleaved-caspase 3 and cell apoptosis were activated. Moreover, the expression of SIRT1, NAMPT, and PGC-1α was downregulated, and the levels of NAD and ATP decreased. In contrast, PE alleviated the 131I-induced mitochondrial damages and upregulated the expression of SIRT1/NAMPT/PGC-1α and the levels of NAD and ATP. CONCLUSIONS: These findings demonstrate that 131I impairs the salivary glands via the downregulation of SIRT1/NAMPT/PGC-1α signal pathways, which disturbs mitochondrial homeostasis. PE alleviated the 131I damage in SMGs at the mitochondrial level, suggesting that PE could be used as a potential radioprotector for patients with differentiated thyroid cancer with radiation sialadenitis.

Photo-induced anti-inflammatory activities of chloro substituted subphthalocyanines on the mammalian macrophage in vitro.

In this study, a series of subphthalocyanines (SubPcs) derivatives were synthesized to generate unique immunomodulatory molecules that can be activated through photo-induction. Immunomodulatory agents have a great potential in medicine to manipulate the immune system according to our needs and prevent disease symptoms. Inflammation is one of these symptoms and macrophages play a crucial role in the generation of inflammatory responses. Being able to control the activity of these agents through photo-induction enables the fine tuning on their activities in a location specific and non-invasive manner with possibly minor side effects. Mammalian macrophages' pro-inflammatory activity was examined in the presence of our compounds as well as LPS as a danger mimic. These compounds exerted photo-induced anti-inflammatory activities on the macrophages. Number of Cl atoms was a defining factor in their photo-induced anti-inflammatory immunomodulatory efficiencies.

Radiation-induced inflammation and autoimmune diseases.

Currently, ionizing radiation (IR) plays a key role in the agricultural and medical industry, while accidental exposure resulting from leakage of radioactive sources or radiological terrorism is a serious concern. Exposure to IR has various detrimental effects on normal tissues. Although an increased risk of carcinogenesis is the best-known long-term consequence of IR, evidence has shown that other diseases, particularly diseases related to inflammation, are common disorders among irradiated people. Autoimmune disorders are among the various types of immune diseases that have been investigated among exposed people. Thyroid diseases and diabetes are two autoimmune diseases potentially induced by IR. However, the precise mechanisms of IR-induced thyroid diseases and diabetes remain to be elucidated, and several studies have shown that chronic increased levels of inflammatory cytokines after exposure play a pivotal role. Thus, cytokines, including interleukin-1(IL-1), tumor necrosis factor (TNF-α) and interferon gamma (IFN-γ), play a key role in chronic oxidative damage following exposure to IR. Additionally, these cytokines change the secretion of insulin and thyroid-stimulating hormone(TSH). It is likely that the management of inflammation and oxidative damage is one of the best strategies for the amelioration of these diseases after a radiological or nuclear disaster. In the present study, we reviewed the evidence of radiation-induced diabetes and thyroid diseases, as well as the potential roles of inflammatory responses. In addition, we proposed that the mitigation of inflammatory and oxidative damage markers after exposure to IR may reduce the incidence of these diseases among individuals exposed to radiation.

How UV Light Touches the Brain and Endocrine System Through Skin, and Why.

The skin, a self-regulating protective barrier organ, is empowered with sensory and computing capabilities to counteract the environmental stressors to maintain and restore disrupted cutaneous homeostasis. These complex functions are coordinated by a cutaneous neuro-endocrine system that also communicates in a bidirectional fashion with the central nervous, endocrine, and immune systems, all acting in concert to control body homeostasis. Although UV energy has played an important role in the origin and evolution of life, UV absorption by the skin not only triggers mechanisms that defend skin integrity and regulate global homeostasis but also induces skin pathology (e.g., cancer, aging, autoimmune responses). These effects are secondary to the transduction of UV electromagnetic energy into chemical, hormonal, and neural signals, defined by the nature of the chromophores and tissue compartments receiving specific UV wavelength. UV radiation can upregulate local neuroendocrine axes, with UVB being markedly more efficient than UVA. The locally induced cytokines, corticotropin-releasing hormone, urocortins, proopiomelanocortin-peptides, enkephalins, or others can be released into circulation to exert systemic effects, including activation of the central hypothalamic-pituitary-adrenal axis, opioidogenic effects, and immunosuppression, independent of vitamin D synthesis. Similar effects are seen after exposure of the eyes and skin to UV, through which UVB activates hypothalamic paraventricular and arcuate nuclei and exerts very rapid stimulatory effects on the brain. Thus, UV touches the brain and central neuroendocrine system to reset body homeostasis. This invites multiple therapeutic applications of UV radiation, for example, in the management of autoimmune and mood disorders, addiction, and obesity.

Effect of the pulsed electromagnetic field on the release of inflammatory mediators from adipose-derived stem cells (ADSCs) in rats.

OBJECTIVE: The aim of this study was to verify if the exposure to the pulsed electromagnetic eld (PEMF) influenced the release of proinflammatory cytokines from adipose-derived stem cells (ADSCs) of normal and overweight rats of various age and sex. Moreover, we compared body temperatures of normal-weight and overweight rats. METHODS: ADSCs of Wistar rats were isolated from the subcutaneous area in females and paratesticular region in males, cultured and exposed to PEMF (7 Hz, 30 mT). Concentrations of proinflammatory cytokines were determined in rat sera and supernatant from ADSCs cultures exposed and non-exposed to PEMF. Body temperature (BT) was measured twice a week, using an infrared and rectal thermometer. RESULTS: Irrespective of age and sex, animals maintained on low-fat (LF) diet had higher BT than those grown on high-fat (HF) diet. Exposure to PEMF reduced the release of TNF-α and enhanced the production of IL-6 in ADSCs cultures from female pups maintained on LF diet. In contrast, a decrease in IL-6 level was observed in PEMF-exposed ADSCs cultures from female pups grown on HF diet. A similar phenomenon, i.e. a post-exposure increase in IL-6 level was also observed in male pups fed with the LF diet. In the case of ADSCs cultures from adult rats maintained on an HF diet, either males or females, PEMF exposure contributed to a dramatic increase in TNF-α production. CONCLUSION: Our findings suggest that PEMF exposure may affect the production of proinflammatory cytokines in ADSCs cultures. The intergroup differences in BT may result from the presence of an underlying inflammation in obese rats.

In Vitro Effects of High-Intensity Laser Photobiomodulation on Equine Bone Marrow-Derived Mesenchymal Stem Cell Viability and Cytokine Expression.

OBJECTIVE: This study aimed to examine the influence of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation on equine bone marrow-derived mesenchymal stem cell (MSC) viability, proliferation, and cytokine expression in vitro. BACKGROUND: Photobiomodulation of cells using monochromatic light is a technique designed to influence cellular processes. Previous studies have shown dose-dependent effects of low-level laser irradiation on cell proliferation and cytokine expression in a range of cell types and species. Evidence for the influence of 1064 nm wavelength near-infrared irradiation on MSCs is sparse, and high-energy doses have shown inhibitory effects. METHODS: MSC cultures from six horses were exposed to 1064 nm irradiation with an energy density of 9.77 J/cm2 and a mean output power of 13.0 W for 10 sec. MSC viability and proliferation were evaluated through flow cytometry and real-time live cell analysis. Gene expression and cytokine production in the first 24 h after irradiation were analyzed through polymerase chain reaction (PCR), multiplex assay, and enzyme-linked immunosorbent assay. RESULTS: No difference in viability was detected between irradiated and control MSCs. Irradiated cells demonstrated slightly lower proliferation rates, but remained within 3.5% confluence of control cells. Twenty-four hours after irradiation, irradiated MSCs demonstrated a significant increase in expression of interleukin (IL)-10 and vascular endothelial growth factor (VEGF) compared with control MSCs. CONCLUSIONS: Under these irradiation parameters, equine MSCs remained viable and expressed increased concentrations of IL-10 and VEGF. IL-10 has an anti-inflammatory action by inhibiting the synthesis of proinflammatory cytokines at the transcriptional level. This response to 1064 nm irradiation shows promise in the photobiomodulation of MSCs to enhance their therapeutic properties.

The Cellular and Molecular Mechanism of Radiation-Induced Lung Injury.

The lung is one of several moderately radiosensitive organs. Radiation-induced lung injury (RILI), including acute radiation pneumonitis and chronic radiation-induced pulmonary fibrosis, occurs most often in radiotherapy of lung cancer, esophageal cancer, and other thoracic cancers. Clinical symptoms of RILI include dry cough, shortness of breath, chest pain, fever, and even severe respiratory failure and death. The occurrence of RILI is a complex process that includes a variety of cellular and molecular interactions which ultimately leads to large fibroblast accumulation, proliferation, and differentiation, resulting in excessive extracellular matrix deposits, causing pulmonary fibrosis. The progress that has been made in recent years in the understanding of cellular and molecular mechanisms of RILI is summarized in this review.

Light-Emitting Diode at 460 ± 20 nm Increases the Production of IL-12 and IL-6 in Murine Dendritic Cells.

BACKGROUND DATA: Light emitting diode (LED) therapy has been proposed as an option for the treatment of many skin inflammatory processes. Dendritic cells (DCs) are important cells of skin that participate in the initiation and activation of skin immunity. The modulation of these cells by LED could explain much of its effects. OBJECTIVE: Thus, the aim of this study was to examine the effects of LED at 460 ± 20 nm on cytokine production and the expression of surface markers on DCs. MATERIALS AND METHODS: DCs were obtained from mouse bone marrow-derived dendritic cells (BMDCs). The LED was applied giving a fluence of 3.3, 8.2, or 16.5 J/cm2 on BMDCs or lipopolysaccharide (LPS)-matured BMDCs. The production of cytokine was analyzed by enzyme linked immunosorbant assay (ELISA) and the expression of DC co- and stimulatory was analyzed markers by cytometry. RESULTS: LED increases IL-12p40 and IL-6 production in both nonstimulated BMDCs and LPS-matured BMDCs. The expression of MHC-II molecule was inhibited and the expression of the CD86 molecule was increased in nonstimulated BMDCs but not in LPS-matured BMDCs. The production of tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) and the expression of CD40 were not altered. CONCLUSIONS: These results demonstrate that LED stimulated cytokine production in BMDCs, suggesting a proinflammatory role in the tested conditions and maybe it can increase DC maturation.

The Antinociceptive Effect of Light-Emitting Diode Irradiation on Incised Wounds Is Correlated with Changes in Cyclooxygenase 2 Activity, Prostaglandin E2, and Proinflammatory Cytokines.

Background. Light-emitting diode (LED) phototherapy has been reported to relieve pain and enhance tissue repair through several mechanisms. However, the analgesic effect of LED on incised wounds has never been examined. Objectives. We examined the analgesic effect of LED therapy on incision pain and the changes in cyclooxygenase 2 (COX-2), prostaglandin E2 (PGE2), and the proinflammatory cytokines interleukin 6 (IL-6), IL-1ß, and tumor necrosis factor α (TNF-α). Methods. Rats received LED therapy on incised skin 6 days before incision (L-I group) or 6 days after incision (I-L group) or from 3 days before incision to 3 days after incision (L-I-L group). Behavioral tests and analysis of skin tissue were performed after LED therapy. Results. LED therapy attenuated the decrease in thermal withdrawal latency in all the irradiated groups and the decrease in the mechanical withdrawal threshold in the L-I group only. The expression levels of COX-2, PGE2, and IL-6 were significantly decreased in the three LED-treated groups, whereas IL-1ß and TNF-α were significantly decreased only in the L-I group compared with their levels in the I groups (p < 0.05). Conclusions. LED therapy provides an analgesic effect and modifies the expression of COX-2, PGE2, and proinflammatory cytokines in incised skin.

The dark side of the light: mechanisms of photocarcinogenesis.

Ultraviolet radiation (UVR) can have a beneficial biologic impact on skin, but it is also the most significant environmental risk factor for skin cancer development. Photocarcinogenesis comprises a complex interplay between the carcinogenic UVR, skin, and the immune system. UVB is absorbed by the superficial skin layers and is mainly responsible for direct DNA damage, which, if unrepaired, can lead to mutations in key cancer genes. UVA is less carcinogenic, penetrates deeper in the dermis, and mainly causes indirect oxidative damage to cellular DNA, proteins, and lipids, via photosensitized reactions. UVR not only induces mutagenesis, altering proliferation and differentiation of skin cells, but also has several immunosuppressive effects that compromise tumor immunosurveillance by impairing antigen presentation, inducing suppressive cells, and modulating the cytokine environment. This review focuses upon molecular and cellular effects of UVR, regarding its role in skin cancer development.

Delayed activation of human microglial cells by high dose ionizing radiation.

Recent studies have shown that microglia affects the fate of neural stem cells in response to ionizing radiation, which suggests a role for microglia in radiation-induced degenerative outcomes. We therefore investigated the effects of γ-irradiation on cell survival, proliferation, and activation of microglia and explored associated mechanisms. Specifically, we evaluated cellular and molecular changes associated with exposure of human microglial cells (CHME5) to low and high doses of acute cesium-137 γ rays. Twenty-four hours after irradiation, cell cycle analyses revealed dose-dependent decreases in the fraction of cells in S and G2/M phase, which correlated with significant oxidative stress. By one week after irradiation, 20-30% of the cells exposed to high doses of γ rays underwent apoptosis, which correlated with significant concomitant decrease in metabolic activity as assessed by the MTT assay, and microglial activation as judged by both morphological changes and increased expression of Glut-5 and CR43. These changes were associated with increases in the mRNA levels for IL-1α, IL-10 and TNFα. Together, the results show that human CHME5 microglia are relatively resistant to low and moderate doses of γ rays, but are sensitive to acute high doses, and that CHME5 cells are a useful tool for in vitro study of human microglia.

Low-level laser irradiation effect on endothelial cells under conditions of hyperglycemia.

Diabetes mellitus is considered to be a very serious lifestyle disease leading to cardiovascular complications and impaired wound healing observed in the diabetic foot syndrome. Chronic hyperglycemia is the source of the endothelial activation. The inflammatory process in diabetes is associated with the secretion of inflammatory cytokines by endothelial cells, e.g., tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6). The method of phototherapy using laser beam of low power (LLLT-low-level laser therapy) effectively supports the conventional treatment of diabetic vascular complications such as diabetic foot syndrome. The aim of our study was to evaluate the effect of low-power laser irradiation at two wavelengths (635 and 830 nm) on the secretion of inflammatory factors (TNF-α and IL-6) by the endothelial cell culture-HUVEC line (human umbilical vein endothelial cell)-under conditions of hyperglycemia. It is considered that adverse effects of hyperglycemia on vascular endothelial cells may be corrected by the action of LLLT, especially with the wavelength of 830 nm. It leads to the reduction of TNF-α concentration in the supernatant and enhancement of cell proliferation. Endothelial cells play an important role in the pathogenesis of diabetes; however, a small number of studies evaluate an impact of LLLT on these cells under conditions of hyperglycemia. Further work on this subject is warranted.

Dysbiosis and Immune Dysregulation in Outer Space.

In space, the lifestyle, relative sterility of spaceship and extreme environmental stresses, such as microgravity and cosmic radiation, can compromise the balance between human body and human microbiome. An astronaut's body during spaceflight encounters increased risk for microbial infections and conditions because of immune dysregulation and altered microbiome, i.e. dysbiosis. This risk is further heightened by increase in virulence of pathogens in microgravity. Health status of astronauts might potentially benefit from maintaining a healthy microbiome by specifically managing their diet on space in addition to probiotic therapies. This review focuses on the current knowledge/understanding of how spaceflight affects human immunity and microbiome.

The Effect of Solar Irradiated Vibrio cholerae on the Secretion of Pro-Inflammatory Cytokines and Chemokines by the JAWS II Dendritic Cell Line In Vitro.

The use of solar irradiation to sterilize water prior to its consumption has resulted in the reduction of water related illnesses in waterborne disease endemic communities worldwide. Currently, research on solar water disinfection (SODIS) has been directed towards understanding the underlying mechanisms through which solar irradiation inactivates the culturability of microorganisms in water, enhancement of the disinfection process, and the health impact of SODIS water consumption. However, the immunological consequences of SODIS water consumption have not been explored. In this study, we investigated the effect that solar irradiated V. cholerae may have had on the secretion of cytokines and chemokines by the JAWS II dendritic cell line in vitro. The JAWS II dendritic cell line was stimulated with the different strains of V. cholerae that had been: (i) prepared in PBS, (ii) inactivated through a combination of heat and chemical, (iii) solar irradiated, and (iv) non-solar irradiated, in bottled water. As controls, LPS (1 µg/ml) and CTB (1 µg/ml) were used as stimulants. After 48 hours of stimulation the tissue culture media from each treatment was qualitatively and quantitatively analysed for the presence of IL-1α, IL-1ß, IL-6, IL-7, IL-10, IL-12p40, IL-12p70, IL-15, MIP-1α, MIP-1ß, MIP-2, RANTES, TNF-α, IL-23 and IL-27. Results showed that solar irradiated cultures of V. cholerae induced dendritic cells to secrete significant (p<0.05) levels of pro-inflammatory cytokines in comparison to the unstimulated dendritic cells. Furthermore, the amount of pro-inflammatory cytokines secreted by the dendritic cells in response to solar irradiated cultures of V. cholerae was not as high as observed in treatments involving non-solar irradiated cultures of V. cholerae or LPS. Our results suggest that solar irradiated microorganisms are capable of inducing the secretion of pro-inflammatory cytokines and chemokines. This novel finding is key towards understanding the possible immunological consequences of consuming SODIS treated water.

Low-dose photon irradiation alters cell differentiation via activation of hIK channels.

To understand the impact of ionizing irradiation from diagnostics and radiotherapy on cells, we examined K(+) channel activity before and immediately after exposing cells to X-rays. Already, low dose in the cGy range caused in adenocarcinoma A549 cells within minutes a hyperpolarization following activation of the human intermediate-conductance Ca(2+)-activated K(+) channel (hIK). The response was specific for cells, which functionally expressed hIK channels and in which hIK activity was low before irradiation. HEK293 cells, which do not respond to X-ray irradiation, accordingly develop a sensitivity to this stress after heterologous expression of hIK channels. The data suggest that hIK activation involves a Ca(2+)-mediated signaling cascade because channel activation is suppressed by a strong cytosolic Ca(2+) buffer. The finding that an elevation of H2O2 causes an increase in the concentration of cytosolic Ca(2+) suggests that radicals, which emerge early in response to irradiation, trigger this Ca(2+) signaling cascade. Inhibition of hIK channels by specific blockers clotrimazole and TRAM-34 slowed cell proliferation and migration in "wound" scratch assays; ionizing irradiation, in turn, stimulated the latter process presumably via its activation of the hIK channels. These data stress an indirect radiosensitivity of hIK channels with an impact on cell differentiation.

Anti-inflammatory effect of 635 nm irradiations on in vitro direct/indirect irradiation model.

Low-level laser therapy (LLLT) has been promoted for its beneficial effects on tissue healing and pain relief. As during laser treatment it is possible to irradiate only a small area of the surface body or wound and, correspondingly, of a very small volume of the circulating blood, it is necessary to explain how its photomodification can lead to a wide spectrum of therapeutic effects. To establish the experimental model for indirect irradiation, irradiation with 635 nm was performed on immortalized human gingival fibroblasts (IGFs) in the presence of Porphyromonas gingivalis lipopolysaccharides (LPS). The irradiated medium was transferred to non-irradiated IGFs which were compared with direct irradiated IGFs. The protein expressions were assessed by Western blot, and prostaglandin E2 (PGE2 ) was measured using an enzyme-linked immunoassay. Reactive oxygen species (ROS) were measured by DCF-DA; cytokine profiles were assessed using a human inflammation antibody array. Cyclooxygenase-2 (COX-2) protein expression and PGE2 production were significantly increased in the LPS-treated group and decreased in both direct and indirect irradiated IGFs. Unlike direct irradiated IGFs, ROS level in indirect irradiated IGFs was decreased by time-dependent manners. There were significant differences of released granulocyte colony-stimulating factor (G-CSF), regulated on activated normal T-cell expressed and secreted (RANTES), and I-TAC level observed compared with direct and indirect irradiated IGFs. In addition, in the indirect irradiation group, phosphorylations of C-Raf and Erk1/2 increased significantly compared with the direct irradiation group. Thus, we suggest that not only direct exposure with 635 nm light, but also indirect exposure with 635 nm light can inhibit activation of pro-inflammatory mediators and may be clinically useful as an anti-inflammatory tool.

The role of oxidative DNA damage in radiation induced bystander effect.

Ionizing radiation (IR) has been described as a double-edged sword, since it is used for diagnostic and therapeutic medical applications, and at the same time it is a well known human mutagen and carcinogen, causing wide-ranging chromosomal aberrations. It is nowadays accepted that the detrimental effects of IR are not restricted only in the irradiated cells, but also to non-irradiated bystander or even distant cells manifesting various biological effects. This review presents the role of oxidative stress in the induction of bystander effects referring to the types of the implicated oxidative DNA lesions, the contributing intercellular and intracellular stress mediators, the way they are transmitted from irradiated to bystander cells and finally, the complex role of the bystander effect in the therapeutic efficacy of radiation treatment of cancer.