Project description:This experiment was conducted to test multiple hypotheses: 1) long-wave 365 nm UV light exposure at low fluences does not alter gene expression of hMSC, 2) presence of radical species during polymerization causes DNA damage in hMSC, 3) 3D encapsulation of hMSC causes changes in gene expression of hMSC compared with traditional 2D culture, 4) Differencesin 3D hydrogel networks induce gene expression changes in hMSC The first publication derived from this data set concerns UV exposure and reactive radical species. Light is a non-invasive tool that is widely used in a range of biomedical applications. Techniques such as photopolymerization, photodegradation and photouncaging can be used to alter the chemical and physical properties of biomaterials in the presence of live cells. Long-wave UV light is an easily accessible and commonly used wavelength. Although exposure to low doses of long-wave UV light is generally accepted as biocompatible, most studies only investigate cell viability, ignoring other possible non-toxic effects. Since light exposure could potentially induce phenotypic changes (i.e. if damage repair mechanisms are activated), we examined changes in gene expression of human mesenchymal stem cells exposed to light under various 2D and 3D culture conditions. While exposure to long-wave UV light did not induce any significant changes in gene expression regardless of culture conditions, significant changes were observed due to scaffold fabrication chemistry and between cells plated in 2D versus 3D scaffolds.
Project description:This experiment was conducted to test multiple hypotheses: 1) long-wave 365 nm UV light exposure at low fluences does not alter gene expression of hMSC, 2) presence of radical species during polymerization causes DNA damage in hMSC, 3) 3D encapsulation of hMSC causes changes in gene expression of hMSC compared with traditional 2D culture, 4) Differencesin 3D hydrogel networks induce gene expression changes in hMSC The first publication derived from this data set concerns UV exposure and reactive radical species. Light is a non-invasive tool that is widely used in a range of biomedical applications. Techniques such as photopolymerization, photodegradation and photouncaging can be used to alter the chemical and physical properties of biomaterials in the presence of live cells. Long-wave UV light is an easily accessible and commonly used wavelength. Although exposure to low doses of long-wave UV light is generally accepted as biocompatible, most studies only investigate cell viability, ignoring other possible non-toxic effects. Since light exposure could potentially induce phenotypic changes (i.e. if damage repair mechanisms are activated), we examined changes in gene expression of human mesenchymal stem cells exposed to light under various 2D and 3D culture conditions. While exposure to long-wave UV light did not induce any significant changes in gene expression regardless of culture conditions, significant changes were observed due to scaffold fabrication chemistry and between cells plated in 2D versus 3D scaffolds. In total, 24 samples were analyzed. Three different culture conditions were created: 2D(plated), 3DR (encapsulated, radical polymerization), and 3DC (encapsulated, conjugate addition). Each culture condition was further subjected to UV radiation or no UV radiation, for 6 total experimental groups. Each experimental group was performed in triplicate. The 2D experimental groups, with and without UV, were additionally performed twice, once simultaneously with the 3DR samples, and once simultaneously with the 3DC samples. 3DR: encapsulated cells using radical polymerization (APS/TEMED) in a poly(ethylene glycol) (MW=4,000 g/mol) hydrogel in PBS. 3DC: encapsulated cells using conjugate addition with a four-arm PEG-Thiol (pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) ) as the cross-linker in PBS.
Project description:The kinetics of DNA repair and RNA synthesis recovery in human cells following UV-irradiation were assessed using nascent RNA Bru-seq and quantitative long PCR. It was found that UV light inhibited transcription elongation and that recovery of RNA synthesis occurred as a wave in the 5’-3’ direction with slow recovery and TC-NER at the 3’ end of long genes. RNA synthesis resumed fully at the 3’-end of genes after a 24-hour recovery in wild-type fibroblasts, but not in cells deficient in transcription-coupled nucleotide excision repair (TC-NER) or global genomic NER (GG-NER). Different transcription recovery profiles were found for individual genes but these differences did not fully correlate to differences in DNA repair of these genes. Our study gives the first genome-wide view of how UV-induced lesions affect transcription and how the recovery of RNA synthesis of large genes are particularly delayed by the apparent lack of resumption of transcription by arrested polymerases.
Project description:The kinetics of DNA repair and RNA synthesis recovery in human cells following UV-irradiation were assessed using nascent RNA Bru-seq and quantitative long PCR. It was found that UV light inhibited transcription elongation and that recovery of RNA synthesis occurred as a wave in the 5’-3’ direction with slow recovery and TC-NER at the 3’ end of long genes. RNA synthesis resumed fully at the 3’-end of genes after a 24-hour recovery in wild-type fibroblasts, but not in cells deficient in transcription-coupled nucleotide excision repair (TC-NER) or global genomic NER (GG-NER). Different transcription recovery profiles were found for individual genes but these differences did not fully correlate to differences in DNA repair of these genes. Our study gives the first genome-wide view of how UV-induced lesions affect transcription and how the recovery of RNA synthesis of large genes are particularly delayed by the apparent lack of resumption of transcription by arrested polymerases. This study is composed of three identical experiments run in three different cell lines. For each experiment, there is one control (mock irradiated cells) and four test samples (0h, 2h, 6h and 24h after UV 10J irradiation).
Project description:Avobenzone, also known as butyl methoxydibenzoylmethane, is extensively used in sunscreen formulations as a long-wave UV A filter to protect human skin from UV A irradiation-induced skin damage. This study was aimed to elucidate the genome-scale transcriptional profile of normal human epidermal keratinocytes (NHEKs) in response to avobenzone.
Project description:Seven-day-old white-light-grown wild-type, cop1-4 or hy5-1 mutant Arabidopsis seedlings were exposed for fifteen minutes to polychromatic radiation with decreasing short-wave cut-off in the UV range (WG305 = +UV-B, WG327 = -UV-B) and samples were taken 1 h after the onset of irradiation.
Project description:In bone marrow (BM), there are two different types of stem/progenitor cells. With respect to hematopoiesis, hematopoietic stem/progenitor cells (HPCs) produce mature blood cells and mesenchymal stromal/stem cells (MSCs) support this. The influence of exposure to low-dose radiation on human HPCs has been investigated, and generation of both immature and mature hematopoietic cells from human HPCs is compromised. On the other hand, the influence of exposure to low-dose radiation on MSCs is not known. This gene expression profiling was created for investigation how low-dose irradiation affects BM-MSCs genomically.
Project description:293T cells are transfected with hsa_circ_0001400 expression plasmid vectors for 24 hours. Cells are then incuvated with Psoralen, exposed to long-wave UV for 10 minutes, and total RNA was extracted. Biotynilated DNA oligos sense (control) or antisense of circ_0001400 are added and circRNA-RNA complexes are enriched using streptavidin beads. RNA was cleaned and exposed to short-wave UV and subjected for RNA-Seq.
Project description:XPA is required for Nucleotide Excision Repair system, which could function to repair DNA damage induced by the UV. UV damage on the genomic DNA cannot be removed, thus persistence of damage could affect the transcriptional machinary. We used the microarray to investigate the global expression profiles in the XP-A and XP-V cells in the low dose of UVC comparing with fibroblast from healthy person.
Project description:The biomedical consequences of space radiation pose a significant concern for astronauts engaged in deep space. However, the effects of long-term low dose-rate exposures in space environments remain elusive. In this study, we simulated the space radiation environment by exposing human bronchial epithelial cells to low dose-rate (0.0067 Gy/day) α-particles, and continuously irradiated them multiple times to achieve cumulative total doses of 0.2 Gy, 0.4 Gy, and 0.5 Gy, respectively. At the same time, the cells were irradiated with the same total dose in a single exposure to investigate the potential of low dose-rate alpha particles to induce malignant transformation of human bronchial epithelial cells. A comprehensive suite of assays was employed to assess tumorigenic potential, including tumor formation in NOD/SCID mice, immunohistochemistry, CCK-8 proliferation assay, invasion assay, and the evaluation of multicellular spheroid formation during subsequent passages post-irradiation. Moreover, we dissected differential malignant mechanisms in tumor evolution ecosystem induced by the two distinct irradiation modes from systems biology views based on scRNA-seq technology. Our results showed that exposure to α-particles, whether through a single acute exposure or long-term low dose-rate exposures, induced the occurrence and development of tumors. Long-term low dose-rate exposures to α-particles increase the malignancy of induced tumors, but not the risk of carcinogenesis, compared to a single acute exposure with the same total dose. In addition, through scRNA-seq, we found that long-term low dose-rate exposures triggered more copy number variation (CNV) and epithelial-mesenchymal transition (EMT) events, and the activation of DNA damage repair pathways occurred significantly later than with a single acute exposure and involved more specific changes in cellular communication dynamics. In conclusion, our findings provide emerging yet convincing evidence that not only sheds light on why cells exposed to long-term low dose-rate exposures exhibit heightened malignancy, but also offers valuable insights into the genetic determinants driving tumor evolution and heterogeneity.