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: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: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:The epidermis is routinely subjected to DNA damage induced by solar (UVB) radiation. In addition to activating canonical DNA damage responses such as cycle cell checkpoints and DNA repair, UVB-induced DNA damage can also activate additional signaling pathways including inflammatory responses. The pathways activated downstream of UVB-induced DNA damage have a critical role in determining cellular survival to UVB radiation. Here we report that loss of CCAAT-enhancer/binding protein β (C/EBPβ) in mouse keratinocytes results in enhanced UVB-induced apoptosis through activation of extrinsic apoptosis genes cleaved caspase-8 and tBid. RNAseq and Ingenuity Pathway Analysis of UVB-treated C/EBPβ-/- primary keratinocytes revealed an enrichment of inflammatory signaling pathways, including the type I interferon (IFN-I) pathway as the most enriched pathway. Numerous IFN-I stimulated genes were up-regulated in UVB-treated C/EBPβ-/- keratinocytes, including genes that regulate extrinsic apoptosis. Inhibition of the interferon / receptor or the associated kinase Tyk2 greatly reduced cell death in UVB-exposed C/EBPβ deficient keratinocytes, demonstrating the dependence of IFN signaling in C/EBPβ regulated apoptosis. The apoptosis inducing cytokine, tumor necrosis factor alpha (TNF-α) was identified as one of the most significant upstream regulators activated in UVB exposed C/EBPβ-/- keratinocytes compared to UVB exposed wild type control. UVB exposed C/EBPβ-/- keratinocytes displayed increased expression of TNF-α and the enhanced apoptosis in C/EBPβ-/- keratinocytes was suppressed by a TNF-α neutralizing antibody. Our results indicate that loss of C/EBPβ enhances activation of a non-canonical UVB DNA damage response pathway involving interferon and TNF signaling to induce keratinocyte cell death.
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: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:Ultraviolet-B irradiation (UVB) induces an epidermal damage response including keratinocyte hyperplasia, immune cell infiltration, and the recruitment of follicular melanocyte stem cells to the interfollicular epidermis. Here, we establish the oncofetal chromatin remodeling factor High mobility group AT-hook 2 (Hmga2) as a regulator of these phenotypes through a cyclic-AMP (cAMP) driven process. In this study, we identify somatic tissue expression of Hmga2 in the basal layer of hyperplastic UVB-exposed keratinocytes. Loss of Hmga2 results in the near absence of epidermal hyperplasia, cutaneous neutrophil infiltration, and melanocyte stem cell migration to the interfollicular epidermis. RNAseq of UVB-exposed keratinocytes from wild-type and Hmga2 loss-of-function models reveals increased expression of Adenosine A1 receptor (Adora1), a negative regulator of cAMP. Administration of the cAMP pathway activator forskolin to Hmga2-/- animals is sufficient to rescue McSC migration, thus highlighting the Hmga2-cAMP axis as a regulator in the cutaneous UVB response.
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).