scholarly journals Suppression of miR135b Increases the Proliferative Potential of Normal Human Keratinocytes

2014 ◽  
Vol 134 (4) ◽  
pp. 1161-1164 ◽  
Author(s):  
Hye-Ryung Choi ◽  
Kyung-Mi Nam ◽  
Sung-Jun Park ◽  
Dong-Seok Kim ◽  
Chang-Hun Huh ◽  
...  
Keyword(s):  
Human Keratinocytes ◽  
Proliferative Potential ◽  
Normal Human Keratinocytes ◽  
Normal Human

scholarly journals Phlorizin, an Active Ingredient ofEleutherococcus senticosus, Increases Proliferative Potential of Keratinocytes with Inhibition of MiR135b and Increased Expression of Type IV Collagen

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Hye-Ryung Choi ◽  
Kyung-Mi Nam ◽  
Hyun-Sun Lee ◽  
Seung-Hye Yang ◽  
Young-Soo Kim ◽  
...  
Keyword(s):  
Type Iv Collagen ◽  
Human Keratinocytes ◽  
Staining Intensity ◽  
Nuclear Antigen ◽  
Proliferative Potential ◽  
Main Ingredient ◽  
Skin Equivalents ◽  
Type Iv ◽  
Normal Human Keratinocytes ◽  
Normal Human

E. senticosusextract (ESE), known as antioxidant, has diverse pharmacologic effects. It is also used as an antiaging agent for the skin and phlorizin (PZ) is identified as a main ingredient. In this study, the effects of PZ on epidermal stem cells were investigated. Cultured normal human keratinocytes and skin equivalents are used to test whether PZ affects proliferative potential of keratinocytes and how it regulates these effects. Skin equivalents (SEs) were treated with ESE and the results showed that the epidermis became slightly thickened on addition of 0.002% ESE. The staining intensity of p63 as well as proliferating cell nuclear antigen (PCNA) is increased, and integrinα6 was upregulated. Analysis of ESE confirmed that PZ is the main ingredient. When SEs were treated with PZ, similar findings were observed. In particular, the expression of integrinα6, integrinβ1, and type IV collagen was increased. Levels of mRNA for type IV collagen were increased and levels of miR135b were downregulated. All these findings suggested that PZ can affect the proliferative potential of epidermal cells in part by microenvironment changes via miR135b downregulation and following increased expression of type IV collagen.

scholarly journals UVB-mediated activation of p38 mitogen-activated protein kinase enhances resistance of normal human keratinocytes to apoptosis by stabilizing cytoplasmic p53

2002 ◽  
Vol 365 (1) ◽  
pp. 133-145 ◽  
Author(s):  
Nadine CHOUINARD ◽  
Kristoffer VALERIE ◽  
Mahmoud ROUABHIA ◽  
Jacques HUOT
Keyword(s):  
Adaptive Response ◽  
Human Keratinocytes ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Dominant Negative Mutant ◽  
Normal Human Keratinocytes ◽  
Mitogen Activated Protein ◽  
Normal Human ◽  
Induced Apoptosis ◽  
Negative Mutant

Human keratinocytes respond to UV rays by developing a fast adaptive response that contributes to maintaining their functions and survival. We investigated the role of the mitogen-activated protein kinase pathways in transducing the UV signals in normal human keratinocytes. We found that UVA, UVB or UVC induced a marked and persistent activation of p38, whereas c-Jun N-terminal kinase or extracellular signal-regulated kinase were less or not activated respectively. Inhibition of p38 activity by expression of a dominant-negative mutant of p38 or with SB203580 impaired cell viability and led to an increase in UVB-induced apoptosis. This sensitization to apoptosis was independent of caspase activities. Inhibition of p38 did not sensitize transformed HaCaT keratinocytes to UVB-induced apoptosis. In normal keratinocytes, expression of a dominant-negative mutant of p53 increased UVB-induced cell death, pointing to a role for p53. In these cells, UVB triggered a p38-dependent phosphorylation of p53 on Ser-15. This phosphorylation was associated with an SB203580-sensitive accumulation of p53, even in the presence of a serine phosphatase inhibitor. Accumulated p53 was localized mainly in the cytoplasm, independently of CRM1 nuclear export. In HaCaT cells, p53 was localized exclusively in the nucleus and its distribution and level were not affected by UVB or p38 inhibition. However, UVB induced an SB203580-insensitive phosphorylation on Ser-15 of mutated p53. Overall, our results suggest that, in normal human keratinocytes, protection against UVB depends on p38-mediated phosphorylation and stabilization of p53 and is tightly associated with the cytoplasmic sequestration of wild-type p53. We conclude that the p38/p53 pathway plays a key role in the adaptive response of normal human keratinocytes against UV stress.

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