Résumé
Skin microbiota is associated with various skin diseases. Scalp hair follicles penetrate deeply into the skin, and carry complex microbial communities distinct from those on the skin surface. Local imbalance of microbial communities may impair the skin barrier function, leading to a variety of hair and scalp diseases. This review discusses changes in microbial diversity and colonization by specific microorganisms in various hair diseases, including dandruff, folliculitis decalvans, etc., and provides new ideas for exploring the pathogenesis of and therapeutic strategies for various hair and scalp diseases.
Résumé
Objective@#To evaluate the in vitro effect of tacrolimus on the expression and function of protease-activated receptor 2 (PAR-2) in cultured human keratinocytes.@*Methods@#After 24-hour co-culture of human keratinocytes with 10-9 - 10-5 mol/L tacrolimus, semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed to determine the mRNA expression of PAR-2, immunofluorescence (IF) staining and Western blot analysis were performed to determine the protein expression of PAR-2 in the keratinocytes, and the fluorescent calcium probe fluo-4 was used to evaluate the effect of tacrolimus at different concentrations on the intracellular calcium concentration after the activation of PAR-2 in the keratinocytes. The group treated without tacrolimus served as control group. One-way analysis of variance was used to compare the PAR-2 expression and calcium concentration in the human keratinocytes in different groups, and least significant difference (LSD) -t test was carried out for multiple comparisons.@*Results@#PAR-2 was expressed on both the membrane and cytoplasm of keratinocytes. After 24-hour co-culture of keratinocytes with 10-9 - 10-5 mol/L tacrolimus, the PAR-2 mRNA expression significantly decreased in these cells compared with the control group (all P < 0.05) , and was negatively correlated with the tacrolimus concentration (r=-0.962, P = 0.009) . IF staining and Western blot analysis showed that the PAR-2 protein expression was significantly lower in the 10-5- and 10-6-mol/L tacrolimus groups than in the control group (both P < 0.05) , and decreased to a certain extent in the 10-7-mol/L tacrolimus group (IF staining: P < 0.05; Western blot analysis: P > 0.05) . No significant difference in the PAR-2 protein expression was observed between the 10-8- or 10-9-mol/L tacrolimus group and the control group (both P > 0.05) . After 24-hour co-culture, the peak concentration of intracellular calcium after PAR-2 activation was significantly lower in the 10-5-, 10-6- and 10-7-mol/L tacrolimus groups (peak absorbance: 1 463 ± 283, 1 455 ± 270, 1 423 ± 291 respectively) than in the control group (1 602 ± 407; t = 2.582, 2.821, 2.923, P = 0.032, 0.022, 0.019, respectively) , while there was no significant difference between the 10-8- or 10-9-mol/L tacrolimus group (1 649 ± 379, 1 633 ± 415 respectively) and the control group (t = 0.846, 0.462, P = 0.422, 0.657, respectively) .@*Conclusion@#Tacrolimus can inhibit PAR-2 expression and suppress calcium mobilization induced by a PAR-2 agonist in keratinocytes.
Résumé
Objective To evaluate the in vitro effect of tacrolimus on the expression and function of protease-activated receptor 2(PAR-2)in cultured human keratinocytes. Methods After 24-hour co-culture of human keratinocytes with 10-9-10-5 mol/L tacrolimus, semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR)was performed to determine the mRNA expression of PAR-2, immunofluorescence(IF)staining and Western blot analysis were performed to determine the protein expression of PAR-2 in the keratinocytes, and the fluorescent calcium probe fluo-4 was used to evaluate the effect of tacrolimus at different concentrations on the intracellular calcium concentration after the activation of PAR-2 in the keratinocytes. The group treated without tacrolimus served as control group. One-way analysis of variance was used to compare the PAR-2 expression and calcium concentration in the human keratinocytes in different groups, and least significant difference(LSD)-t test was carried out for multiple comparisons. Results PAR-2 was expressed on both the membrane and cytoplasm of keratinocytes. After 24-hour co-culture of keratinocytes with 10 - 9- 10 - 5 mol/L tacrolimus, the PAR-2 mRNA expression significantly decreased in these cells compared with the control group(all P < 0.05), and was negatively correlated with the tacrolimus concentration(r=-0.962, P=0.009). IF staining and Western blot analysis showed that the PAR-2 protein expression was significantly lower in the 10-5- and 10-6-mol/L tacrolimus groups than in the control group (both P < 0.05), and decreased to a certain extent in the 10-7-mol/L tacrolimus group(IF staining:P<0.05;Western blot analysis:P>0.05). No significant difference in thePAR-2 protein expression was observed between the 10-8-or 10-9-mol/L tacrolimus group and the control group(both P>0.05). After 24-hour co-culture, the peak concentration of intracellular calcium after PAR-2 activation was significantly lower in the 10-5-, 10-6- and 10-7-mol/L tacrolimus groups (peak absorbance:1463 ± 283, 1455 ± 270, 1423 ± 291 respectively)than in the control group(1602 ± 407;t=2.582, 2.821, 2.923, P=0.032, 0.022, 0.019, respectively), while there was no significant difference between the 10-8-or 10-9-mol/L tacrolimus group(1649 ± 379, 1633 ± 415 respectively)and the control group(t=0.846, 0.462, P=0.422, 0.657, respectively). Conclusion Tacrolimus can inhibit PAR-2 expression and suppress calcium mobilization induced by a PAR-2 agonist in keratinocytes.
Résumé
Objective To detect the expression of proteinase activated receptor 2 (PAR-2) in the skin of patients with atopic dermatitis (AD) and to evaluate the effects of tacrolimus on the expression.Methods Six patients with acute moderate or severe AD were enrolled in this study and topically treated with tacrolimus 0.1％ ointment twice daily for 3 weeks.Tissue samples were obtained from the lesions and non-lesional skin at least 10 cm away from the lesions before and after the 3-week treatment.Skin specimens from 6 normal human controls served as the control.Patients were evaluated at the baseline,1 and 3 weeks after the beginning of treatment for clinical symptoms and signs by visual analogue scale (VAS),eczema area and severity index (EASI) and investigator's global assessment (IGA).The expression of PAR-2 in tissue specimens were determined by immunohistochemistry.Results PAR-2 was expressed throughout the whole epidermis,especially in the granular layer,hair follicles,sweat glands,endothelial cells and nerve fiber-like structures.Before treatment,the expression level (mean optical density) of PAR-2 in keratinocytes was 4339.6 ± 115.8 in lesional skin of AD patients,significantly higher than that in non-lesional skin (4189.0 t 228.9,t =2.85,P ＜0.05) and in normal skin (3864.0 ± 237.3,t =4.31,P ＜ 0.05).After the 3-week treatment with tacrolimus ointment,the expression level of PAR-2 significant decreased to 3942.4 ± 176.6 in keratinocytes from lesional skin of patients with AD (t =4.55,P ＜ 0.05).The expression level of PAR-2 was positively correlated with VAS score for itch,EASI and IGA score in the patients.Conclusions The expression of PAR-2 is enhanced in keratinocytes of lesions from AD patients,and is positively correlated with itch and lesion severity.Topical tacrolimus may suppress the overexpression of PAR-2 in keratinocytes in lesional skin of AD.
Résumé
Objective To study the role of cutaneous nerve and protease activated receptor 2 (PAR2)in the development of pruritus in atopic dermatitis(AD).Methods Dermal sheets were prepared from chronically pruritic skin lesions of 7 patients with AD,as well as from the normal skin of 7 healthy human controls.Double labeled immunofluorescence was performed using mouse anti-protein gene product 9.5(PGP9.5)monoclonal antibody and rabbit anti-substance P(SP)polyclonal antibody to observe the morphological changes in cutaneous nerve fibers,and Image-Pro Plus 6 software was used to semiquantitively assess the length,diameter of nerve fibers,integral optimal density of PAR2 and SP in dermal sheets.Results Immunofluoresence double staining showed that PAR2 co-expressed with PGP9.5 or SP in cutaneous nerve fibers.Compared with the normal control skin,both the total length and average diameter of PGP 9.5-expressing nerve fibers were increased(11051.8±1900.9 μm vs 7264.0±2659.9 μm,4.23±0.15 μm vs 3.95±0.15 μm,both P＜0.01)in pruritic lesions,while only the average diameter of SP-expressing nerve fibers was up-regulated(3.99±0.20 μm vs 3.80±0.07 μm,P＜0.05),and the total length of them remained unchanged(4304.7±1455.0 μm vs 3380.0±1735.4 μm,P＞0.05).Also,increased integral optimal density was observed for SP and PAR in pruritic lesions in comparison with the normal control skin (27.71±16.52 vs 12.63±4.31.35.99±8.63 vs 22.69±9.56.both P＜0.05).Conclusion Our results indicate a hyper-plasia of cutaneous nerve fibers in chronic itchv skin lesions of AD and an increase in the expression of PAR2 and SP in the cutaneous nerve fibers,suggesting that the signal enhancement in PAR2 pathway may be related to the mechanism of pruritus in patients with AD.