- Vie Mar 22, 2019 10:08 pm
#703560
En resumen: Sandal petanol = Sandalore
1 ) Chemical stimulation of human microdissected HFs with OR2AT4 s a n d a l p e n t a n o l ( agonist) and Phenirat (antagonist)
After 24h of incubation, WEM medium was replaced and HFs were treated with the corresponding substances for 6 days following experimental conditions. HFs were treated either with vehicle (0.1 % DMSO), sandal pentanol (500 μΜ), Phenirat (in a ratio 1 :1 to the agonist), or a mixture sandal pentanol+Phenirat.
Phenirat was added 30 min before sandal pentanol. Hair shaft elongation was measured daily using an inverted binocular microscope (Philpott et al., 1990) and culture medium was replaced every second day. HFs were then embedded in cryomatrix (Fisher Scientific) and snap frozen in liquid nitrogen. Sections of 6 μιτι thickness were cut with a cryostat and stored at -80 °C for further immunohistochemical analysis.
Quantitative (immuno-)histomorphometry
Staining intensity was evaluated in well-defined reference areas by quantitative (im- muno-)histomorphometry, as previously described (Bertolini et al., 2014) using NIH IMAGE software (NIH, Bethesda, MD, USA).
Statistical analyses
All data are expressed as mean ± SEM and were analysed by One Way Anova or Kruskall Wallis test when more than 2 groups were compared and Student's t-test or Mann-Whitney test when sandal pentanol treatment was compared to vehicle (Graph Pad Prism 6, GraphPad Software, San Diego, CA, USA).
RESULTS
Results are described with reference to the enclosed drawings of Figs. 1 to 5.
1 ) Human HFs express the Olfactory Receptor 2AT4
Firstly the presence of the olfactory receptor 2AT4 (OR2AT4) in HFs was investigated. OR2AT4 was observed in the suprabulbar outer root sheath (ORS) keratino- cytes of human scalp anagen HFs, as shown by immunofluorescence in Figure 1 . Pictures A) to D) from Fig. 1 represent OR2AT4 immunofluorescence in HFs in human scalp skin (see picture A and corresponding enlargements) and microdissected HFs (see pictures B-D and corresponding enlargements) from three different donors (n=3). CTS stands for connective tissue sheath, DP for dermal papilla, HM for hair matrix, IRS for inner root sheath, ORS for outer root sheath, HS for hair shaft, HB for hair bulb, HF for hair follicles. Dotted lines delineate the IRS (inner root sheath), ORS (outer root sheath) and DP (dermal papilla).
Fig. 1 shows that OR2AT4 is expressed in suprabulbar ORS keratinocytes of anagen scalp HFs and in suprabulbar and bulbar ORS, and in hair matrix tips keratinocytes in microdissected anagen HFs.
Microdissected anagen HFs (Philpott model) revealed OR2AT4 cells in the hair bulb, namely in ORS and hair matrix (HM) tips, see Fig.1 B, in addition to the characteristic suprabulbar intrafollicular expression, see Fig. 1 D.
2) Specific stimulation of OR2AT4 by sandal pentanol promotes hair shaft elongation and inhibits apoptotic signalling pathway
To check whether the activation of OR2AT4 can influence the hair cycle of human HF, microdissected human HFs were specifically stimulated with the potential agonist, sandal pentanol. The effect of the sandal pentanol treatment was evaluated by measuring hair shaft elongation compared to vehicle.
HF elongation was measured in cultured microdissected HFs. Mean±SEM, n=18 HFs for each donor, 2 donors, Student's t-test, Graph Pad Prism 6. Despite inter- individual differences, the results reveal that sandal pentanol at concentration 5 00 μ Μ stimulates hair shaft elongation of cultured microdissected HFs deriving from two donors, as shown in the diagram of Fig. 2 reporting % elongation versus days of culture, sandalore compared to vehicle.
3) The activation of OR2AT4 by sandal pentanol significantly delays catagen induction and decreases apoptosis in human hair matrix keratinocytes
To investigate the specificity of the effect on hair growth of OR2AT4 stimulation by sandal pentanol, microdissected HFs were cultured with sandal pentanol and/or Phenirat, and hair cycle performed staging analysis as previously described (Kloepper, 2010; Langan et al, 2015). Hair cycle score was measured both in treated and vehicle HFs after 6 days of culture. N=16-24 HFs from 3 patients, Mean±SEM, Kruskal Wallis test and Dunn's multiple comparisons test as post hoc test, ns, Mann-Whitney test, #p<0.05, Graph Pad Prism 6.
The obtained results indicate that the specific stimulation of OR2AT4 by sandal pentanol alone at concentration 500 μ Μ delayed catagen induction in treated HFs compared to vehicle after 6 days of culture, as shown in the diagram of Figure 3. On the contrary, both comparative reference Phenirat alone and the mixture of sandal pentanol administered together with Phenirat did not prolong anagen in treated HFs compared to vehicle. The data suggest that the stimulation of OR2AT4 by sandal pentanol promotes catagen delay, whilst these effects are counteracted by OR2AT4 inhibition when using Phenirat.