Project description:Dr. Liu's research group is interested in studying the expression and functions of galectin-3, -7 and -12, in particular the roles of these proteins in inflammation and neoplasm. Members of the galectin family are known to participate in cellular homeostasis by modulating cell growth, controlling cell cycle progression, and inducing or inhibiting apoptosis. It is known that some galectins have similar functions. However, it is not fully understood whether they work cooperatively or not. As the outermost barrier of the body, skin is directly and frequently exposed to a prooxidative environment, including solar ultraviolet A (UVA), ultraviolet B (UVB) radiation, and air pollution. Several reports have shown that exposure of cells to UV increase or decrease the levels of galectins. For example, the amounts of galectin-7 mRNA and protein are increased rapidly after UVB irradiation of keratinocytes (Proc. Natl. Acad. Sci. USA 1999; 96:11329-34). Heat shock and subculturing decrease, while alkylating agents and UV-light increase galectin-3 (Cell Physiol Biochem 2000; 10:149-58). To analyze the change of all galectin gene expression profiles after UVB irradiation and to determine the presence or absence of coordinate regulation, we analyzed the gene expression profiles of keratinocytes exposed to UVB. Normal human epidermal keratinocytes (NHEK) were irradiated with 200 J/m2 of UVB. Total RNA will be extracted at 0, 6, 12 and 24 h after irradiation (duplicate) for analysis on the Glyco gene chip. Several reports have shown that exposure to UV light can regulate levels of galectin in skin. This study seeks to analyze the changes in all galectin gene expression profiles post-UVB irradiation to determine the presence or absence of coordinate regulation. In this study, normal human keratinocytes were irradiated with 200J/m2 of UVB. Total RNA was extracted at 0, 6, 12, and 24-hour post irradiation time points, in duplicate. Samples were hybridized and analyzed using the GLYCOv2 array.
Project description:Dr. Liu's research group is interested in studying the expression and functions of galectin-3, -7 and -12, in particular the roles of these proteins in inflammation and neoplasm. Members of the galectin family are known to participate in cellular homeostasis by modulating cell growth, controlling cell cycle progression, and inducing or inhibiting apoptosis. It is known that some galectins have similar functions. However, it is not fully understood whether they work cooperatively or not. As the outermost barrier of the body, skin is directly and frequently exposed to a prooxidative environment, including solar ultraviolet A (UVA), ultraviolet B (UVB) radiation, and air pollution. Several reports have shown that exposure of cells to UV increase or decrease the levels of galectins. For example, the amounts of galectin-7 mRNA and protein are increased rapidly after UVB irradiation of keratinocytes (Proc. Natl. Acad. Sci. USA 1999; 96:11329-34). Heat shock and subculturing decrease, while alkylating agents and UV-light increase galectin-3 (Cell Physiol Biochem 2000; 10:149-58). To analyze the change of all galectin gene expression profiles after UVB irradiation and to determine the presence or absence of coordinate regulation, we analyzed the gene expression profiles of keratinocytes exposed to UVB. Normal human epidermal keratinocytes (NHEK) were irradiated with 200 J/m2 of UVB. Total RNA will be extracted at 0, 6, 12 and 24 h after irradiation (duplicate) for analysis on the Glyco gene chip.
Project description:We identified a pro-apoptotic function of Nrf3 in keratinocytes after UVB irradiation. To determine the underlying mechanism of action we wanted to compare the transcriptome of wt and Nrf3-ko mouse keratinocytes before and after 24 h 100 mJ/cm2 UVB irradiation
Project description:Purpose: To compare the transcriptomes of UVB (20mJ/cm2 and 40mJ/cm2) exposed and untreated HaCaT keratinocytes by RNA-Seq analysis, trying to find differences in gene expression between UVB exposed and untreated of keratinocytes and then elucidate the candidate genes that may play important roles in the differentiation of UVB-induced damage in keratinocytes. Methods: HaCaT keratinocytes were subjected to 20mJ/cm2 and 40mJ/cm2 UVB irradiation. Results: To better understand the effects of UVB (20 mJ/cm2), mRNA-sequecing (n=3) were completed by Novogene Inc. A total 891 differentially expressed genes (DEGs) were identified between UV group and control group with 604 down-regulated and 287 up-regulated. A total of 4036 differentially expressed genes (DEGs) which compared with untreated group were identified by RNA-Seq, which provided abundant data for further analysis.
Project description:Unprotected exposure to UVB radiation from the sun and the resulting DNA damage are thought to be responsible for physiological changes in the skin and for a variety of skin cancers, including basal cell and squamous cell carcinoma and malignant melanoma. Although the mutagenic effects of UVB have been well documented and studied mechanistically, there is only limited information as to whether UV light may also be responsible for inducing epigenetic changes in the genome of exposed cells. DNA methylation is a stable epigenetic modification involved in gene control. To study the effects of UVB radiation on DNA methylation, we repeatedly exposed normal human keratinocytes to a UVB light source. After a recovery period, we analyzed global DNA methylation patterns in the irradiated and control cells using the methylated-CpG island recovery assay (MIRA) method in combination with high-resolution microarrays. Bioinformatics analysis revealed only a limited number of possible differences between UVB-exposed and control cells. However, these minor apparent changes could not be independently confirmed by bisulfite sequencing-based approaches. This study reveals that UVB irradiation of keratinocytes has no recognizable global effect on DNA methylation patterns and suggests that changes in DNA methylation, as observed in skin cancers, are not immediate consequences of human exposure to solar UVB irradiation. DNA methylation analysis of control and UVB irradiated keratinocytes. The MIRA assay was used for enrichment of methylated DNA. NimbleGen CpG island plus promoter arrats were used.
Project description:Dr. Liu's research group is interested in studying the expression and functions of galectin-3, -7 and -12, in particular the roles of these proteins in inflammation and neoplasm. Members of the galectin family are known to participate in cellular homeostasis by modulating cell growth, controlling cell cycle progression, and inducing or inhibiting apoptosis. It is known that some galectins have similar functions. However, it is not fully understood whether they work cooperatively or not. Recent reports suggest that gal-3 deficiency may induce changes in cellular homeostatic mechanisms, leading to changes in expression of other galectins and galectin-related proteins. To analyze the coordinate regulation of galectins in the face of gal-3 deficiency, gene expression patterns of gal-3 / and gal-3 -/- keratinocytes exposed to UVB were compared. Murine epidermal keratinocytes from gal-3 / and gal-3 -/- mice will be irradiated with 200 J/m2 of UVB. Total RNA will be extracted at 0, 6, 12 and 24 h after irradiation. Classes were prepared in triplicate for a total of 24 samples. All samples were hybridized to the custom designed CFG GLYCOv2 glycogene array.
Project description:Unprotected exposure to UVB radiation from the sun and the resulting DNA damage are thought to be responsible for physiological changes in the skin and for a variety of skin cancers, including basal cell and squamous cell carcinoma and malignant melanoma. Although the mutagenic effects of UVB have been well documented and studied mechanistically, there is only limited information as to whether UV light may also be responsible for inducing epigenetic changes in the genome of exposed cells. DNA methylation is a stable epigenetic modification involved in gene control. To study the effects of UVB radiation on DNA methylation, we repeatedly exposed normal human keratinocytes to a UVB light source. After a recovery period, we analyzed global DNA methylation patterns in the irradiated and control cells using the methylated-CpG island recovery assay (MIRA) method in combination with high-resolution microarrays. Bioinformatics analysis revealed only a limited number of possible differences between UVB-exposed and control cells. However, these minor apparent changes could not be independently confirmed by bisulfite sequencing-based approaches. This study reveals that UVB irradiation of keratinocytes has no recognizable global effect on DNA methylation patterns and suggests that changes in DNA methylation, as observed in skin cancers, are not immediate consequences of human exposure to solar UVB irradiation.
Project description:Gene expression in wild-type and p38a-knockout keratinocytes were compared. Keratinocytes were isolated from newborn mice, and left unirradiated (0 h) and irradiated (4 h) with ultraviolet-B (UVB). C57BL/6 wild-type mice, and keratinocyte-specific p38a-knockout mice on a C57BL/6 background were used for isolation of primary keratinocytes. Gene expression in keratinocytes was analyzed 0 and 4 h after UVB irradiation (75 mJ/cm2).
Project description:Considering that human skin cancer is predominantly attributed to UV radiation from sunlight, additional investigations are needed to elucidate the role of P2RY6 in UVB-induced skin carcinogenesis. Surprisingly, we find that P2ry6 deletion exhibits marked promotion to UVB-induced skin papilloma formation compared with wild-type mice, suggesting its tumor-suppressive role in UVB-induced skin cancer. Additionally, P2ry6 knockout promotes mouse skin hyperplasia induced by short-term UVB irradiation, while UDP, the ligand of P2RY6, can inhibit UVB-induced skin damage. Furthermore, UVB irradiation can significantly upregulate P2RY6 expression in mouse and human skin cells. These results indicate that P2RY6 plays a crucial protective role in resisting UVB-induced skin damage and carcinogenesis. At the molecular level, P2RY6 deletion inhibits ubiquitination and expression of XPC after UVB irradiation in keratinocytes, resulting in the accumulation of CPDs (cyclobutane pyrimidine dimers). P2RY6 deletion also activates PI3K/AKT signaling pathway in vitro and in vivo. The CPD accumulation and inflammatory responses enhanced by P2RY6 deletion are reversed by an AKT inhibitor. These findings suggest that P2RY6 acts as a tumor suppressor in UVB-induced skin cancer by regulating PI3K/AKT signaling pathway.
Project description:Purpose: to explore the function and mechanism of skin damage induced by ultraviolet irradiation. The mouse model of UVB irradiation was established. Using miRNA Sequence analysis, the miRNA expression profile of the mouse skin model exposed to UVB radiation and the normal skin mice. GO and Pathway analysis were employed for the prediction of miRNA targets. Results:Compared with normal skin, a total of 23 miRNAs were screened for significantly different expressions. Among them, 7 miRNAs were up-regulated and 16 were down-regulated in the skin wound tissue of mice exposed to UVB irradiation. The differential expression of miRNA is related to a variety of signal transduction pathways, among which mmu-miR-195a-5p and mitogen-activated protein kinase (MAPK) signal pathway is worthy of attention. Conclusion: There was significant difference expression of miRNA in the skin tissue of normal mice and the skin injury induced by UVB irradiation. Differential expression of miRNA can be used in the diagnosis and treatment of UVB-induced acute skin injury.