Ultraviolet B Downregulated Aquaporin 1 Expression via the MEK/ERK pathway in the Dermal Fibroblasts

Background@#Aquaporin 1 (AQP1) is a transmembrane channel protein that allows rapid transposition of water and gases, in recent discoveries of AQP1 function involve cell proliferation, differentiation, wound healing, inflammation and infection in different cell types, suggesting that AQP1 plays key roles in diverse biologic process. Until now, less is known about the function of AQP1 on ultraviolet radiation induced photoaged skin. @*Objective@#In this study we set out to examine whether AQP1 expression may be influenced by repeated irradiation of ultraviolet B (UVB) in cultured dermal fibroblasts. @*Methods@#To elucidate the function of AQP1 in skin photoaging, human dermal fibroblasts (HS68) were irradiated by a series of 4 sub-cytotoxic doses of UVB which are known as UV-induced cell premature senescence model. Reverse transcription polymerase chain reaction and Western blotting were conducted to detect AQP1 expression from different groups. Then, cells were transfected with AQP1-targeting small interfering RNA. The activities of signaling proteins upon UVB irradiation were investigated to determine which pathways are involved in AQP1 expression. @*Results@#AQP1 expression was increased by 100 mJ/cm2 of UVB irradiation, but decreased by 200 mJ/cm2. Depletion of the AQP1 increased the apoptotic sensitivity of cells to UVB, as judged by upregulation of the p53, p21, poly (adenosine diphosphate [ADP]-ribose) polymerase and Bax together with the increased Bax/Bcl2 ratio. UVB induced downregulation of AQP1 was significantly attenuated by pretreatment with the MEK/ERK inhibitor (PD98059). @*Conclusion@#We concluded that AQP1 expression was down-regulated by repeated exposure of UVB via MEK/ERK activation pathways. The AQP1 reduction by UVB lead to changes of physiological functions in dermal fibroblasts, which might be associated with the occurrence and development of UVB induced photoaging.

Poly-L-Lactic Acid Increases Collagen Gene Expression and Synthesis in Cultured Dermal Fibroblast (Hs68) Through the p38 MAPK Pathway

No abstract available.

Alterations of p16INK4A Gene in Korean Squamous Cell Carcinoma and Basal Cell carcinoma of the Skin / 대한피부과학회지

BACKGROUND: The inactivation of the cyclin dependent kinase 4 inhibitor p16INK4A may be caused by deletion, mutations or promoter hyper-methylation. Recently, DNA methylation of p16INK4A promoter has been shown to suppress of p16INK4A gene transcription in various tumors. OBJECTIVE: We analyzed the gene status of p16INK4A in squamous cell carcinoma (SCC) and basal call carcinoma (BCC) of the Korean skin to investigate whether the inactivation of the gene participated in carcinogenesis. METHODS: We examined 12 SCC and 3 BCC cell lines using PCR to detect homozygous deletion of chromosome 9p21 region and methylation-specific PCR. RESULTS: Deletion of the p16INK4A gene were not, but methylation of the p16INK4A promoter region was common in SCC of the skin. CONCLUSION: These results suggest that de novo methylation of the p16INK4A promoter region seems to play an important role in the pathogenesis of SCC.

FKBP-12 Exhibits an Inhibitory Activity on Calcium Oxalate Crystal Growth in Vitro

Urolithiasis and calcium oxalate crystal deposition diseases are still significant medical problems. In the course of nephrocalcin cDNA cloning, we have identified FKBP-12 as an inhibitory molecule of calcium oxalate crystal growth. lambdagt 11 cDNA libraries were constructed from renal carcinoma tissues and screened for nephrocalcin cDNA clones using anti-nephrocalcin antibody as a probe. Clones expressing recombinant proteins, which appeared to be antigenically cross-reactive to nephrocalcin, were isolated and their DNA sequences and inhibitory activities on the calcium oxalate crystal growth were determined. One of the clone lambdagt 11 #31-1 had a partial fragment (80 bp) of FKBP-12 cDNA as an insert. Therefore, a full-length FKBP-12 cDNA was PCR-cloned from the lambdagt 11 renal carcinoma cDNA library and was subcloned into an expression vector. The resultant recombinant FKBP-12 exhibited an inhibitory activity on the calcium oxalate crystal growth (Kd=10(-7) M). Physiological effect of the extracellular FKBP-12 was investigated in terms of macrophage activation and proinflammatory cytokine gene induction. Extracellular FKBP-12 failed to activate macrophages even at high concentrations. FKBP-12 seems an anti-stone molecule for the oxalate crystal deposition disease and recurrent stone diseases.

The Effects of Epigallocatechin Gallate on Ultraviolet B Irradiated Cultured Human Skin Fibroblasts / 대한피부과학회지

BACKGROUND: The main polyphenol components in green tee are (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate (EGCG). It is well known that flavonoids such as catechins can be protective against inflammatory and cancer and cardiovascular diseases. These protective effects are largely due to their inhibition of some enzymes and antioxidative activities by scavenging free radicals. Ultraviolet(UV) exposure of the skin, particulary UVB (290-320nm), causes adverse biological effects, including alterations in cutaneous immune cells, photoaging and photocarcinogenesis. Several studies have shown that EGCG afforded protection against UVB-induced inflammatory responses and photocarcinogenesis in murine models. OBJECTIVE AND METHODS: In this study, we investigated the effects of EGCG on UVB irradiated human skin fibroblasts using viability test, thiobarbituric acid assay, propidium iodide(PI) stain, and western blot analyses and RT-PCR. RESULTS: Cell survival curves after UVB irradiation showed dose dependent decrement pattern by trypan blue exclusion assay. Only 42% of dermal fibroblasts survived at 150 mJ/cm2 UVB irradiation. The damage was associated with cell membrane lipid peroxidation, as shown by accumulation malondialdehyde(MDA). By pre-cultivation with EGCG (50nmol), a significant preventive effect was noted on the increase in the absolute number of surviving cells(up to 81.5% of cells survived) and the levels of MDA markedly decreased. Morphological changes associated with apoptotic cell death were easily distinguished by PI stain. Bases on our finding, we investgated the regulation of p53, p21, bax, bcl-2, cyclin D1, E, Cdk2, and PARP proteins by western blot analyses. The expression p53 protein was elevated by following UVB exposure which was inhibited by EGCG treatment. Using RT-PCR, the transcription of p53, fas and jun gene showed similar results which obtained by western blot analyses. CONCLUSION: EGCG, which have newly accepted as a potential UV protection properties, is effective membrane peroxidation inhibitor and prevent apoptotic changes when present in relevant concentration at the site of action beginning and during UVB irradiation. And the protective mechanism of EGCG against UVB-induced cell damage maybe, at least in part, related with p53, fas and jun pathway.

The c-myc expression on the opioid tolerance in human neuroblastoma SH-SY5Y cells

The mechanisms underlying opiate tolerance and dependence are not fully understood. We used human neuroblastoma SH-SY5Y cells as a model system for studying effects of morphine tolerance and withdrawal on c-myc induction and cAMP levels. It has been reported that regulation of c-fos by acute and chronic morphine withdrawal is mediated through alterations in CREB transcription factor. In this study, we examined the effects of morphine tolerance on c-myc expression and cAMP concentrations. The activation of opiate receptors by an acute morphine administration resulted in an increase in c-myc mRNA and a decrease in cAMP concentrations in a dose-dependent manner (5, 10, 15, and 20 muM). On the other hand, the chronic treatment of morphine (10 muM for six days) did not induce the elevated expression of c-myc mRNA. The c-myc expression was slightly inhibited in comparison with that of the acute morphine response. However, cAMP concentrations were increased with regard to morphine withdrawal response. These results suggest that the alterations in c-myc expression might imply a significant opiate regulation relating to morphine tolerance. This observation differs from increased expression of c-fos via regulation of cAMP pathway.