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treatment groups and the control group. KGF also facilitates HFSC proliferation. In this study, HFSCs
were isolated from the hair follicle bulge and the effects
After 48 h of culture, the KGF 10 µg/L treatment group was of different concentrations of LiCl and KGF on HFSC
significantly different as compared with the control group proliferation and differentiation were explored.
(P < 0.05), but there was no difference between the control
group and the other KGF-dose treatment groups. After 72 LiCl, a crucial Wnt signaling agonist, inhibits the activity
h of culture, the KGF 10 µg/L treatment group showed a of GSK-3β. [11] GSK-3 phosphorylation at serine-9 prevents
significant increase in proliferation when compared with the GSK-3β from degrading β-catenin, thus elevating β-catenin
control group (P < 0.01). However, there was no observed expression. This study found that low LiCl concentrations
[14]
difference between the control group and the other KGF- (0-10 mmol/L) not only induce β-catenin expression but also
dose treatment groups. After 96 h of culture, the 10, 25, and slightly increase HFSCs proliferation. However, proliferation
100 µg/L KGF treatment groups showed a significant increase decreased as the LiCl concentration was increased. LiCl
in proliferation when compared with the control group (P < treatment also led to a reduction in cell adhesion and
0.01). However, there was no significant difference between caused HFSCs to grow in dispersed clusters. This is a result
the control group and the 50 µg/L KGF treatment group. of LiCl inhibiting intracellular E-cadherin expression, which
After 120 h of culture, all doses of KGF had significantly weakens cell adhesion and facilitates cell migration. This
[15]
increased the proliferation of HFSCs compared with the phenomenon may result from E-cadherin transposition
control group (P < 0.05). caused by β-catenin up-regulation. These data suggest that
changes in β-catenin expression can change cell adhesion,
Effects of LiCl and KGF on HFSC differentiation and which has an important role in promoting cell proliferation.
morphology.
In the current study, β-catenin expression directly correlated
There were obvious differences in cell morpho- with the β-catenin-axin-APC-GSK-3β complex, but inversely
differentiation, adhesion, and proliferation between the correlated with GSK-3β and axin levels. Axin, a critical
10 mmol/L LiCl and 10 µg/L KGF treatment groups and the negative regulator of the Wnt signaling pathway, is a key
control group [Figure 10A-D]. The LiCl 10 µg/L treatment component of the β-catenin degradation complex. It has
group showed a significant increase in proliferation [Figure several protein-protein interaction domains and functions
10E-H]. By contrast, the proliferation rate of KGF-treated cells as scaffolding protein in various protein complexes. Axin
initially increased in a dose-dependent manner. However, brings GSK-3β in close proximity to β-catenin and regulates
cell proliferation decreased with aging and vacuoles formed the degradation of phosphorylated β-catenin. This study
within the cells at later time points [Figure 10I-L]. demonstrated that LiCl suppresses the expression of GSK-3β
mRNA and thus inhibits the formation of the axin complex,
Effects of LiCl and KGF on the mRNA expression of which indirectly elevates the level of β-catenin.
components of the Wnt/β-catenin signaling pathway.
As a downstream transcription factor in the Wnt signaling
Following treatment with 10 mmol/L LiCl, the mRNA pathway, LEF1activates the transcription of specific
expression of β-catenin was increased when compared with genes. According to recent reports, [7,8,16] endogenous LEF1
control cells. There was also an increased expression of APC synergizes with Wnt signaling. It is widely accepted that
and LEF1 mRNA, but a gradual reduction in axin and GSK-3β β-catenin activates downstream target genes through a
mRNA expression [Figure 11]. complex formation with LEF1. Cofactor ALY, enhancer TCRα,
and LEF1 cooperatively form a higher-order nucleoprotein
Following treatment with 10 µg/L KGF, the expression of complex that enhances the synergistic activation of
β-catenin mRNA did not change markedly compared with β-catenin/LEF1 and thus transcriptional activity. This study
[16]
control cells; however, GSK-3β and LEF1 mRNA expression found that LiCl treatment increased the levels of β-catenin
gradually declined [Figure 12]. and LEF1 mRNA along with the course induce. It is likely
that increased protein levels of β-catenin complex with
DISCUSSION LEF1. These results are identical with those of the above-
mentioned mechanisms of the Wnt signaling pathway, and
HFSC differentiation is regulated by multiple factors, which indicate that activations of the β-catenin and LEF1 signaling
[1]
interact to form an intricate regulatory system. [1,2] The main pathways are involved in HFSC’s differentiation.
intrinsic regulatory factors affecting HFSC proliferation and
differentiation are Wnt, β-catenin and the Notch and exit Numerous studies have shown that β-catenin functions by
domain A (EDA) signaling pathways. [1,10-12] Extrinsic signals forming a complex with LEF1 in the Wnt signaling pathway. [17-20]
primarily include mitogens, intercellular interactions, cell Zhu et al. transfected keratinocytes with retrovirus and found
[17]
growth factors [e.g. basic fibroblast growth factor (bFGF) that mutant LEF1 expressed in the basal lamina of transgenic
and EGF], and some chemical substances (e.g. LiCl). [13-15] mice cannot interact with β-catenin. Thus, hair formation is
These signals constitute the external microenvironment of prevented and adult basal epidermal cells are transformed
proliferation and differentiation of HFSCs. KGF is a member into pluripotent embryonic-like ectoderm. LEF1 is an essential
of the FGF superfamily, which regulates the proliferation transcriptional factor for the normal development of hair
and differentiation of various cell types. KGF expression in follicles. LEF1 expression stimulates the stem cell to develop into
matrix cells is sharply upregulated when skin is injured. hair, facilitates differentiation of both hair matrix cells and hair
[13]
Plast Aesthet Res || Vol 3 || Issue 2 || Feb 29, 2016 45