Distinguish response of low-dose radiation with different dose-rate on gene expression of human coronary artery endothelial cells: a bioinformatic study based on transcriptomic sequencing.

PURPOSE: People are exposed to low-dose radiation in medical diagnosis, occupational, or life circumstances, but the effect of low-dose radiation on human health is still controversial. The biological effects of radiation below 100 mGy are still unproven. In this study, we observed the effects of low-dose radiation (100 mGy) on gene expression in human coronary artery endothelial cells (HCAECs) and its effect on molecular signaling. MATERIALS AND METHODS: HCAECs were exposed to 100 mGy ionizing radiation at 6 mGy/h (low-dose-rate) or 288 mGy/h (high-dose-rate). After 72 h, total RNA was extracted from sham or irradiated cells for Quant-Seq 3'mRNA-Seq, and bioinformatic analyses were performed using Metascape. Gene profiling was validated using qPCR. RESULTS: Compared to the non-irradiated control group, 100 mGy of ionizing radiation at 6 mGy/h altered the expression of 194 genes involved in signaling pathways related to heart contraction, blood circulation, and cardiac myofibril assembly differentially. However, 100 mGy at 288 mGy/h altered expression of 450 genes involved in cell cycle-related signaling pathways, including cell division, nuclear division, and mitosis differentially. Additionally, gene signatures responding to low-dose radiation, including radiation dose-specific gene profiles (HIST1H2AI, RAVER1, and POTEI) and dose-rate-specific gene profiles (MYL2 for the low-dose-rate and DHRS9 and CA14 for the high-dose-rate) were also identified. CONCLUSIONS: We demonstrated that 100 mGy low-dose radiation could alter gene expression and molecular signaling pathways at the low-dose-rate and the high-dose-rate differently. Our findings provide evidence for further research on the potential impact of low-dose radiation on cardiovascular function.

Identification of DNA methylation biomarkers for evaluating cardiovascular disease risk from epigenome profiles altered by low-dose ionizing radiation.

BACKGROUND: Environmental exposure, medical diagnostic and therapeutic applications, and industrial utilization of radionuclides have prompted a growing focus on the risks associated with low-dose radiation (< 100 mGy). Current evidence suggests that such radiation can induce epigenetic changes. Nevertheless, whether exposure to low-dose radiation can disrupt endothelial cell function at the molecular level is unclear. Because endothelial cells play crucial roles in cardiovascular health and disease, we aimed to investigate whether low-dose radiation could lead to differential DNA methylation patterns at the genomic level in endothelial cell (EC) lines. METHODS: We screened for changes in DNA methylation patterns in primary human aortic (HAECs) and coronary artery endothelial cells following exposure to low-dose ionizing radiation. Using a subset of genes altered via DNA methylation by low-dose irradiation, we performed gene ontology (GO) analysis to predict the possible biological network mediating the effect of low-dose radiation. In addition, we performed comprehensive validation using methylation and gene expression analyses, and ChIP assay to identify useful biomarkers among candidate genes for use in detecting low-dose radiation exposure in human primary normal ECs. RESULTS: Low-dose radiation is sufficient to induce global DNA methylation alterations in normal EC lines. GO analysis demonstrated that these hyper- or hypo-methylated genes were linked to diverse biological pathways. Our findings indicated a robust correlation between promoter hypermethylation and transcriptional downregulation of four genes (PGRMC1, UNC119B, RERE, and FNDC3B) in response to low-dose ionizing radiation in HAECs. CONCLUSIONS: Based on these findings, the identified genes can serve as potential DNA methylation biomarkers for the assessment of cardiovascular risk upon exposure to low-dose radiation.

Comparison of cellular responses to ionizing radiation in keratinocytes isolated from healthy donors and type II diabetes patients.

PURPOSE: Due to the expanding repertoire of treatment devices that use radiation, the possibility of exposure to both low-dose and high-dose radiation continues to increase. Skin is the outermost part of the body and thus directly exposed to radiation-induced damage. In particular, the skin of diabetes patients is fragile and easily damaged by external stimuli, such as radiation. However, damage and cellular responses induced by ionizing irradiation in diabetic skin have not been explored in detail. In this study, we investigated the effects of several irradiation dose on normal keratinocytes and those from type II diabetes patients, with particular focus on DNA damage. MATERIALS AND METHODS: Cellular responses to low-dose radiation (0.1 Gy) and high-dose radiation (0.5 and 2 Gy) were evaluated. Cell cycle analysis was conducted via flow cytometry and cell viability analyzed using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. Proteins related to the DNA damage response (DDR) and repair signaling pathways and apoptosis were detected via immunoblot analysis. Apoptosis and cell differentiation were additionally examined in 3D skin organoids using immunohistochemistry. RESULTS: Compared to respective control groups, no significant changes were observed in cell cycle, DDR and repair mechanisms, cell survival, and differentiation in response to 0.1 Gy irradiation in both normal and diabetes type II keratinocytes. On the other hand, the cell cycle showed an increase in the G2/M phase in both cell types following exposure to 2 Gy irradiation. At radiation doses 2 Gy, activation of the DDR and repair signaling pathways, apoptosis, and cell differentiation were increased and viability was decreased in both cell types. Notably, these differences were more pronounced in normal than diabetes type II keratinocytes. CONCLUSIONS: Normal keratinocytes respond more strongly to radiation-induced damage and recovery than diabetes type II keratinocytes.

miR-765 as a promising biomarker for low-dose radiation-induced pulmonary fibrosis.

High-dose radiation (HDR) is widely used for cancer treatment, but the effectiveness of low-dose radiation (LDR) in the treatment of various diseases is controversial. Therefore, to safely utilize LDR for therapeutic purposes, further research on its numerous biological effects of LDR is required. Interest in the increased use of medical imaging devices or the effects of surrounding living environmental radiation on the human body, particularly on fibrosis, is rapidly increasing. Therefore, this study aimed to verify the relationship between LDR and pulmonary fibrosis by evaluating the changes in fibroblasts after LDR treatment and their associated signaling mechanisms. LDR increased the expression of fibrosis markers COL1A1 and α-SMA, cell proliferation, and migration by activating YAP1 and Twist in fibroblasts. Meanwhile, miRNA was employed as a tool to inhibit LDR-induced fibrosis and it was found that miR-765 simultaneously targeted COL1A1, α-SMA, and YAP1. At the cellular level, miR-765 reduced the proliferation and migration of fibroblasts by suppressing the expression of LDR-induced fibrosis factors COL1A1, α-SMA, and YAP1. The efficacy of miR-765 in vivo was confirmed using bleomycin (BLM)-induced fibrotic mouse model. The characteristics of pulmonary fibrosis were reduced after injection of miR-765-overexpressing cells into BLM-induced fibrotic mice. In addition, the suppression of miR-765 expression in the plasma of patients with pulmonary fibrosis confirmed the negative relationship between pulmonary fibrosis and miR-765 expression. Therefore, this study demonstrates that miR-765 is a potential novel diagnostic biomarker and major target for the development of therapeutic agents to inhibit pulmonary fibrosis.

Low dose rate radiation impairs early follicles in young mice.

Low-dose radiation is generally considered less harmful than high-dose radiation. However, its impact on ovaries remains debated. Since previous reports predominantly employed low-dose radiation delivered at a high dose rate on the ovary, the effect of low-dose radiation at a low dose rate on the ovary remains unknown. We investigated the effect of low-dose ionizing radiation delivered at a low dose rate on murine ovaries. Three- and ten-week-old mice were exposed to 0.1 and 0.5 Gy of radiation at a rate of 6 mGy/h and monitored after 3 and 30 days. While neither body weight nor ovarian area showed significant changes, ovarian cells were damaged, showing apoptosis and a decrease in cell proliferation after exposure to 0.1 and 0.5 Gy radiation. Follicle numbers decreased over time in both age groups proportionally to the radiation dose. Younger mice were more susceptible to radiation damage, as evidenced by decreased follicles in 3-week-old mice after 30 days of 0.1 Gy exposure, while 10-week-old mice showed reduced follicles only following 0.5 Gy exposure. Primordial or primary follicles were the most vulnerable to radiation. These findings suggest that even low-dose radiation, delivered at a low dose rate, can adversely affect ovarian function, particularly in the early follicles of younger mice.

Long-term radiofrequency electromagnetic fields exposure attenuates cognitive dysfunction in 5×FAD mice by regulating microglial function.

We have previously found that long-term effects of exposure to radiofrequency electromagnetic fields in 5×FAD mice with severe late-stage Alzheimer's disease reduced both amyloid-ß deposition and glial activation, including microglia. To examine whether this therapeutic effect is due to the regulation of activated microglia, we analyzed microglial gene expression profiles and the existence of microglia in the brain in this study. 5×FAD mice at the age of 1.5 months were assigned to sham- and radiofrequency electromagnetic fields-exposed groups and then animals were exposed to 1950 MHz radiofrequency electromagnetic fields at a specific absorption rate of 5 W/kg for 2 hours/day and 5 days/week for 6 months. We conducted behavioral tests including the object recognition and Y-maze tests and molecular and histopathological analysis of amyloid precursor protein/amyloid-beta metabolism in brain tissue. We confirmed that radiofrequency electromagnetic field exposure for 6 months ameliorated cognitive impairment and amyloid-ß deposition. The expression levels of Iba1 (pan-microglial marker) and colony-stimulating factor 1 receptor (CSF1R; regulates microglial proliferation) in the hippocampus in 5×FAD mice treated with radiofrequency electromagnetic fields were significantly reduced compared with those of the sham-exposed group. Subsequently, we analyzed the expression levels of genes related to microgliosis and microglial function in the radiofrequency electromagnetic fields-exposed group compared to those of a CSF1R inhibitor (PLX3397)-treated group. Both radiofrequency electromagnetic fields and PLX3397 suppressed the levels of genes related to microgliosis (Csf1r, CD68, and Ccl6) and pro-inflammatory cytokine interleukin-1ß. Notably, the expression levels of genes related to microglial function, including Trem2, Fcgr1a, Ctss, and Spi1, were decreased after long-term radiofrequency electromagnetic field exposure, which was also observed in response to microglial suppression by PLX3397. These results showed that radiofrequency electromagnetic fields ameliorated amyloid-ß pathology and cognitive impairment by suppressing amyloid-ß deposition-induced microgliosis and their key regulator, CSF1R.

Low-dose-rate ionizing radiation affects innate immunity protein IFITM3 in a mouse model of Alzheimer's disease.

PURPOSE: Although the adverse health risks associated with low-dose radiation (LDR) are highly debated, relevant data on neuronal function following chronic LDR exposure are still lacking. MATERIALS AND METHODS: To confirm the effect of chronic LDR on the progression of Alzheimer's disease (AD), we investigated changes in behavior and neuroinflammation after radiation exposure in wild-type (WT) and 5xFAD (TG) mice, an animal model of AD. WT and TG mice, classified by genotyping, were exposed to low-dose-rate radiation for 112 days, with cumulative doses of 0, 0.1, and 0.3 Gy, then evaluated using the open-field and Y-maze behavioral function tests. Changes in the levels of APP processing- and neuroinflammation-related genes were also investigated. RESULTS: No apparent change was evident in either non-spatial memory function or locomotor activity, as examined by the Y-maze and open field tests, respectively. Although chronic LDR did not affect the levels of APP processing, gliosis (Iba1 and GFAP), or inflammatory cytokines (IL-1ß, IL-6, and TNF-α), the levels of IFN-γ were significantly downregulated in TG mice following LDR exposure. In an additional analysis, we examined the genes related to IFN signaling and found that the levels of interferon induced transmembrane protein 3 (IFITM3) were decreased significantly in TG mice following LDR with 0.1 or 0.3 Gy. CONCLUSIONS: Therefore, this study revealed the possibility that LDR could affect the progression of AD, which may be associated with decreased IFN-related signaling, especially IFITM3. Our findings suggest that further studies are required regarding the potential role of LDR in the progression of AD.

EFFECT OF ABDOMINAL IRRADIATION IN MICE MODEL OF INFLAMMATORY BOWEL DISEASE.

Inflammatory bowel diseases could be diagnosed in major measure by diagnostic imaging; however, radiation exposure in the intestine may also contribute to the progression of these pathologies. To better understand the impact of radiation in the presence of bowel disease, we administered dextran sodium sulfate (DSS) to C57BL/6 mice to induce colitis and exposed to radiation at abdominal area. We observed that abdominal irradiation (13 Gy) aggravates the DSS-induced decrease in survival rate (0%), body weight (74.54 ± 3.59%) and colon length (4.98 ± 0.14 cm). Additionally, abdominal irradiation markedly increased in colonic inflammation levels (3.16 ± 0.16) compared with that of DSS-induced sham mice. Furthermore, abdominal irradiation also increased the mRNA expression levels of inflammatory genes, such as cyclooxygenase-2 (13.10 folds), interleukin-6 (48.83 folds) and tumor necrosis factor-alpha (42.97 folds). We conclude that abdominal irradiation aggravates the detrimental effects of DSS-induced colitis in mice, which might be a useful guideline for inflammatory bowel disease patients.

Effects of intermediate frequency electromagnetic fields: a review of animal studies.

PURPOSE: Many novel devices such as induction cookers or wireless power transfer produce electromagnetic fields (EMFs) in the intermediate frequency (IF) range (300 Hz to 10 MHz) and it is very meaningful for summarizing the bioeffects of IF-EMF research, particularly animal studies. This review takes into account experimental studies that used murine models to study the health effects of exposure to IF-EMF. The analyses included here use data available in the literature published from January 1988 to August 2021 including the animal studies about general adverse effects, tumorigenic effects, and effects on developmental stages. The studies that linked IF-EMF exposure during pregnancy or neonatal stage to behavioral and cognition changes were included. Additionally, this review also covers the effects of IF-EMF on gene expression patterns in the brain, behavior patterns associated with learning and memory, and immune function. CONCLUSIONS: Although most studies have suggested that IF-EMF is harmless, some adverse effects have been reported after exposure at developmental stages and prolonged exposure. Compared to extremely low frequency (ELF) or radiofrequency (RF) EMF bands, studies on health effects with more diverse perspectives of IF-EMF have not been conducted. Therefore, performing more research should be necessary using the latest biomedical tools. From this point of view, a comprehensive review of IF-EMF studies, particularly animal studies, will provide a valuable basis for further risk analysis in humans.

Effect of radiofrequency exposure on body temperature: Real-time monitoring in normal rats.

Radiofrequency radiation (RFR) can generate heat in living organisms. In this study, we monitored the body temperature of healthy animals during RFR exposure in real time using an implantable iButton data logger. A reverberation chamber system for small animals was used for this radiofrequency (RF) exposure in vivo study. Healthy male Sprague-Dawley rats were divided into two groups: with versus without iButton implantation (n = 20 per group). Each group was further divided into a sham-exposed and RF-exposed group (n = 10 per subgroup). Rats were exposed to a 1,760-MHz long-term evolution (LTE) signal in the reverberation chamber system at a whole-body average specific absorption rate of 0 W/kg (sham-exposed) or 4 W/kg (RF-exposed) for 6 h. The body temperature of iButton-implanted rats was recorded using an intraperitoneally implanted iButton every minute over 6 h of RF exposure, whereas that of non-implanted rats was measured directly using a rectal thermometer immediately before and after the 6-h RF exposure period. The temperature values measured by the two types of thermometers were significantly positively correlated (r = 0.63, P < 0.01, linear regression), and changes in body temperatures recorded in iButton-implanted and non-implanted rats measured using two thermometers after 6 h of RF exposure were maintained within <1°C (P = 0.87, general linear model, followed by univariate model). Similar results were obtained for rectal thermometer measurements (P = 0.12, paired t-test). These results suggest that RF exposure at a whole-body average specific absorption rate of 4 W/kg does not induce significant changes in body temperature in healthy rats over a 6-h RF exposure period.

Protective effects of an aqueous extract of Protaetia brevitarsis seulensis larvae against radiation-induced testicular injury in mice.

The larvae of Protaetia brevitarsis seulensis have been used as a food ingredient and are known for their nutritional value and anti-inflammatory properties. However, whether P. brevitarsis seulensis larvae demonstrate protective effects against radiation-induced testicular injury has not been investigated. In this study, the protective effects of an aqueous extract of P. brevitarsis seulensis larvae (PBE) against radiation-induced testicular injury were tested. Male C57BL/6 mice were administered PBE (5 or 10 mg/kg) orally for 14 days before exposure to focal pelvic irradiation. Histopathological examinations were conducted at 8 h and 30 d after radiation exposure. PBE pretreatment reduced the radiation-induced apoptosis of germ cells at 8 h after irradiation and significantly increased testis and epididymis weights relative to those of the irradiated control mice at 30 days. PBE protected against histopathological damage and decreased the radiation-induced effects on the epithelium height and seminiferous tubule diameter. Furthermore, the extract ameliorated the radiation-induced morphological abnormalities of sperm cells and improved their motility. It also prevented a decrease in the epididymal sperm count caused by irradiation. Moreover, the extract alleviated the generation of reactive oxygen species, and its antioxidative activity increased in a dose-dependent manner. Among the six major compounds isolated from PBE, benzoic acid and uridine showed the highest antioxidant activities. These results suggest that PBE protects against radiation-induced testicular injury via its antioxidative properties. Thus, it has potential clinical applicability as a neoadjuvant therapy for the prevention of testicular damage caused by cancer radiotherapy.

The Potential Neuroprotective Effects of Extracts from Oat Seedlings against Alzheimer's Disease.

The physiological or dietary advantages of germinated grains have been the subject of numerous discussions over the past decade. Around 23 million tons of oats are consumed globally, making up a sizeable portion of the global grain market. Oat seedlings contain more protein, beta-glucan, free amino acids, and phenolic compounds than seeds. The progressive neurodegenerative disorder of Alzheimer's is accompanied by worsening memory and cognitive function. A key indicator of this disorder is the unusual buildup of amyloid-beta protein (or Aß) in human brains. In this context, oat seedling extract (OSE) has been identified as a new therapeutic candidate for AD, due to its antioxidant activity and AD-specific mechanism of action. This study directly investigated how OSE affected AD and its impacts by examining the cognitive function and exploring the inflammatory response mechanism. The dried oat seedlings were grounded finely with a grinder, inserted with 50% fermented ethanol 10 times (w/v), and extracted by stirring for 10 h at 45 °C. After filtering the extract by 0.22 um filter, some of it was used for UHPLC analysis. The results indicated that the treatment with OSE protects against Aß25-35-induced cytotoxicity in BV2 cells. Tg-5Xfad AD mice had strong deposition of Aß throughout their brains, while WT mice did not exhibit any such deposition within their brains. A drastic reduction was observed in terms of numbers, as well as the size, of Aß plaques within Tg-5Xfad AD mice exposed to OSE. This study indicated OSE's neuroprotective impacts against neurodegeneration, synaptic dysfunction, and neuroinflammation induced by amyloid-beta. Our results suggest that OSE acts as a neuroprotective agent to combat AD-specific apoptotic cell death, neuroinflammation, amyloid-beta accumulation, as well as synaptic dysfunction in AD mice's brains. Furthermore, the study indicated that OSE treatment affects JNK/ERK/p38 MAPK signaling, with considerable inhibition in p-JNK, p-p38, and p-ERK levels seen in the brain of OSE-treated Tg-5Xfad AD mice.

Tuning of Peptide Cytotoxicity with Cell Penetrating Motif Activatable by Matrix Metalloproteinase-2.

Although diverse cell penetrating motifs not only from naturally occurring proteins but also from synthetic peptides have been discovered and developed, the selectivity of cargo delivery connected to these motifs into the desired target cells is generally low. Here, we demonstrate the selective cytotoxicity tuning of an anticancer KLA peptide with a cell penetrating motif activatable by matrix metalloproteinase-2 (MMP2). The anionic masking sequence introduced at the end of the KLA peptide through an MMP2-cleavable linker is selectively cleaved by MMP2 and the cationic cell penetrating motif is activated. Upon treatment of the peptide to H1299 cells (high MMP2 level), it is selectively internalized into the cells by MMP2, which consequently induces membrane disruption and cell death. In contrast, the peptide shows negligible cytotoxicity toward A549 cancer cells with low MMP2 levels. Furthermore, the selective therapeutic efficacy of the peptide induced by MMP2 is also corroborated using in vivo study.

Low-Dose Radiation Affects Cardiovascular Disease Risk in Human Aortic Endothelial Cells by Altering Gene Expression under Normal and Diabetic Conditions.

High doses of ionizing radiation can cause cardiovascular diseases (CVDs); however, the effects of <100 mGy radiation on CVD remain underreported. Endothelial cells (ECs) play major roles in cardiovascular health and disease, and their function is reduced by stimuli such as chronic disease, metabolic disorders, and smoking. However, whether exposure to low-dose radiation results in the disruption of similar molecular mechanisms in ECs under diabetic and non-diabetic states remains largely unknown; we aimed to address this gap in knowledge through the molecular and functional characterization of primary human aortic endothelial cells (HAECs) derived from patients with type 2 diabetes (T2D-HAECs) and normal HAECs in response to low-dose radiation. To address these limitations, we performed RNA sequencing on HAECs and T2D-HAECs following exposure to 100 mGy of ionizing radiation and examined the transcriptome changes associated with the low-dose radiation. Compared with that in the non-irradiation group, low-dose irradiation induced 243 differentially expressed genes (DEGs) (133 down-regulated and 110 up-regulated) in HAECs and 378 DEGs (195 down-regulated and 183 up-regulated) in T2D-HAECs. We also discovered a significant association between the DEGs and the interferon (IFN)-I signaling pathway, which is associated with CVD by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, protein−protein network analysis, and module analysis. Our findings demonstrate the potential impact of low-dose radiation on EC functions that are related to the risk of CVD.

Low Dose Rate Radiation Regulates M2-like Macrophages in an Allergic Airway Inflammation Mouse Model.

We investigated the effects of low dose rate radiation (LDR) on M1 and M2 macrophages in an ovalbumin-induced mouse model of allergic airway inflammation and asthma. After exposure to LDR (1 Gy, 1.818 mGy/h) for 24 days, mice were euthanized and the changes in the number of M1 and M2 macrophages in the bronchoalveolar lavage fluid and lung, and M2-associated cytokine levels, were assessed. LDR treatment not only restored the M2-rich microenvironment but also ameliorated asthma-related progression in a macrophage-dependent manner. In an ovalbumin-induced mouse model, LDR treatment significantly inhibited M2, but not M1, macrophage infiltration. M2-specific changes in macrophage polarization during chronic lung disease reversed the positive effects of LDR. Moreover, the levels of cytokines, including chemokine (C-C motif) ligand (CCL) 24, CCL17, transforming growth factor beta 1, and matrix metalloproteinase-9, decreased in ovalbumin-sensitized/challenged mice upon exposure to LDR. Collectively, our results indicate that LDR exposure suppressed asthmatic progression, including mucin accumulation, inflammation, and Type 2 T helper (Th2) cytokine (interleukin (IL)-4 and IL-13) production. In conclusion, LDR exposure decreased Th2 cytokine secretion in M2 macrophages, resulting in a reduction in eosinophilic inflammation in ovalbumin-sensitized/challenged mice.

Profiling of gene expression in the brain associated with anxiety-related behaviors in the chronic phase following cranial irradiation.

Although the brain is exposed to cranial irradiation in many clinical contexts, including malignant brain tumor therapy, such exposure can cause delayed neuropsychiatric disorders in the chronic phase. However, how specific molecular mechanisms are associated with irradiation-induced behavioral dysfunction, especially anxiety-like behaviors, is unclear. In the present study, we evaluated anxiety-like behaviors in adult C57BL/6 mice using the open-field (OF) and elevated plus maze (EPM) tests 3 months following single cranial irradiation (10 Gy). Additionally, by using RNA sequencing (RNA-seq), we analyzed gene expression profiles in the cortex and hippocampus of the adult brain to demonstrate the molecular mechanisms of radiation-induced brain dysfunction. In the OF and EPM tests, mice treated with radiation exhibited increased anxiety-like behaviors in the chronic phase. Gene expression analysis by RNA-seq revealed 89 and 106 differentially expressed genes in the cortex and hippocampus, respectively, following cranial irradiation. Subsequently, ClueGO and STRING analyses clustered these genes in pathways related to protein kinase activity, circadian behavior, and cell differentiation. Based on our expression analysis, we suggest that behavioral dysfunction following cranial irradiation is associated with altered expression of Cdkn1a, Ciart, Fos, Hspa5, Hspb1 and Klf10. These novel findings may provide potential genetic targets to investigate for the development of radioprotective agents.

No-ozone cold plasma can kill oral pathogenic microbes in H2O2-dependent and independent manner.

To apply the sterilisation effect of low-temperature plasma to the oral cavity, the issue of ozone from plasma must be addressed. In this study, a new technology for generating cold plasma with almost no ozone is developed and is named Nozone (no-ozone) Cold Plasma (NCP) technology. The antimicrobial efficacy of the NCP against four oral pathogens is tested, and its specific mechanism is elucidated. The treatment of NCP on oral pathogenic microbes on a solid medium generated a growth inhibition zone. When NCP is applied to oral pathogens in a liquid medium, the growth of microbes decreased by more than 105 colony forming units, and the bactericidal effect of NCP remained after the installation of dental tips. The bactericidal effect of NCP in the liquid medium is due to the increase in hydrogen peroxide levels in the medium. However, the bactericidal effect of NCP in the solid medium depends on the charged elements of the NCP. Furthermore, the surface bactericidal efficiency of the dental-tip-installed NCP is proportional to the pore size of the tips and inversely proportional to the length of the tips. Overall, we expect this NCP device to be widely used in dentistry in the near future.

2-Methoxyestradiol Inhibits Radiation-Induced Skin Injuries.

Radiation-induced skin injury (RISI) is a main side effect of radiotherapy for cancer patients, with vascular damage being a common pathogenesis of acute and chronic RISI. Despite the severity of RISI, there are few treatments for it that are in clinical use. 2-Methoxyestradiol (2-ME) has been reported to regulate the radiation-induced vascular endothelial-to-mesenchymal transition. Thus, we investigated 2-ME as a potent anti-cancer and hypoxia-inducible factor 1 alpha (HIF-1α) inhibitor drug that prevents RISI by targeting HIF-1α. 2-ME treatment prior to and post irradiation inhibited RISI on the skin of C57/BL6 mice. 2-ME also reduced radiation-induced inflammation, skin thickness, and vascular fibrosis. In particular, post-treatment with 2-ME after irradiation repaired the damaged vessels on the irradiated dermal skin, inhibiting endothelial HIF-1α expression. In addition to the increase in vascular density, post-treatment with 2-ME showed fibrotic changes in residual vessels with SMA+CD31+ on the irradiated skin. Furthermore, 2-ME significantly inhibited fibrotic changes and accumulated DNA damage in irradiated human dermal microvascular endothelial cells. Therefore, we suggest that 2-ME may be a potent therapeutic agent for RISI.

Ionizing Radiation-Induced GDF15 Promotes Angiogenesis in Human Glioblastoma Models by Promoting VEGFA Expression Through p-MAPK1/SP1 Signaling.

Glioblastoma multiforme (GBM), the most aggressive cancer type that has a poor prognosis, is characterized by enhanced and aberrant angiogenesis. In addition to surgical resection and chemotherapy, radiotherapy is commonly used to treat GBM. However, radiation-induced angiogenesis in GBM remains unexplored. This study examined the role of radiation-induced growth/differentiation factor-15 (GDF15) in regulating tumor angiogenesis by promoting intercellular cross-talk between brain endothelial cells (ECs) and glioblastoma cells. Radiation promoted GDF15 secretion from human brain microvascular endothelial cells (HBMVECs). Subsequently, GDF15 activated the transcriptional promoter VEGFA in the human glioblastoma cell line U373 through p-MAPK1/SP1 signaling. Upregulation of vascular endothelial growth factor (VEGF) expression in U373 cells resulted in the activation of angiogenic activity in HBMVECs via KDR phosphorylation. Wound healing, tube formation, and invasion assay results revealed that the conditioned medium of recombinant human GDF15 (rhGDF15)-stimulated U373 cell cultures promoted the angiogenic activity of HBMVECs. In the HBMVEC-U373 cell co-culture, GDF15 knockdown mitigated radiation-induced VEGFA upregulation in U373 cells and enhanced angiogenic activity of HBMVECs. Moreover, injecting rhGDF15-stimulated U373 cells into orthotopic brain tumors in mice promoted angiogenesis in the tumors. Thus, radiation-induced GDF15 is essential for the cross-talk between ECs and GBM cells and promotes angiogenesis. These findings indicate that GDF15 is a putative therapeutic target for patients with GBM undergoing radio-chemotherapy.

Development of an atmospheric plasma jet device for versatile treatment of electron microscope sample grids.

Atmospheric-pressure plasmas have been widely applied for surface modification and biomedical treatment because of their ability to generate highly reactive radicals and charged particles. In negative-stain electron microscopy (Neg-EM) and cryogenic electron microscopy (cryo-EM), plasmas have been used to generate hydrophilic surfaces and eliminate surface contaminants to embed specimens onto grids. In addition, plasma treatment is a prerequisite for negative-stain and Quantifoil grids, whose surfaces are coated with hydrophobic amorphous carbon. Although the conventional glow discharge system has been used successfully in this purpose, there has been no further effort to take an advantage from the recent progress in the plasma field. Here, we developed a nonthermal atmospheric plasma jet system as an alternative tool for treatment of surfaces. The low-temperature plasma is a nonequilibrium system that has been widely used in biomedical area. Unlike conventional glow discharge systems, the plasma jet system successfully cleans and introduces hydrophilicity on the grid surface in the ambient environment without a vacuum. Therefore, we anticipate that the plasma jet system will have numerous benefits, such as convenience and versatility, as well as having potential applications in surface modification for both negative-stain and cryo-EM grid treatment.