TLR9的生物学特性及其在生殖器疱疹发病中的意义

Toll样受体9属于模式识别受体(pattern recognition receptor,PRR)的一种,属于天然免疫系统的一部分,人体可能通过TLR9来识别HSV-2基因中的CpGDNA,启动天然免疫系统,活化DCs,以依赖MyD88的信号传导通路促使IFN-α分泌,诱导Th1型细胞免疫应答,以对抗生殖器疱疹病毒感染。深入认识TLR9的作用机理为DNA疫苗的应用提供理论依据。     

Distichiasis-lymphoedema: clinical features, venous function and lymphoscintigraphy

Distichiasis-lymphoedema is a rare variant of the genetically determined lymphoedemas; distichiasis is the abnormal development of the meibomian glands causing aberrant growth of eyelashes. However, a better understanding of this clinically distinct subgroup may provide useful information on the genetic inheritance of all types of lymphoedema. This report provides phenotype data on a very large family with distichiasis-lymphoedema. Lymphoscintigraphy and light reflection rheography (venous function) were undertaken to identify the phenotype more clearly. As a result of lymphoscintigraphy several subjects were reclassified phenotypically (unaffected or affected) with implications for genetic linkage studies. Associated congenital abnormalities were found and venous abnormalities were almost always present in affected limbs. A dominant inheritance with incomplete penetrance was confirmed.     

Squamous cell carcinoma arising in Hailey-Hailey disease of the vulva

A 61-year-old woman, who was known to have Hailey-Hailey disease, presented with increasing vulval soreness. Biopsy showed vulval intraepithelial neoplasia (VIN) 3 and subsequent histology from a vulvectomy specimen showed extensive VIN with early invasive squamous cell carcinoma. This may be another example of chronic inflammation of the vulval area leading to the development of squamous cell carcinoma. However, in this case, chronic human papillomavirus may also have played a part, leading to VIN and reactivation of the Hailey-Hailey disease. We can find no previous reports of squamous cell carcinoma developing in the setting of Hailey-Hailey disease.     

Determination of plasma fibronectin in congenital epidermolysis bullosa

Comme il est possible que la fibronectine (FN) ait un rapport avec la formation ou la guérison des bulles dans des cas d'épidermolyse bulleuse congénitale (É.B.C.), nous avons effectué les dosages de FN plasmatique dans 10 cas d'É.B.C. (3 É.B. simples, 2 É.B. dystrophiques dominantes, 5 É.B. dystrophiques recessives). Les taux de FN plasmatique ne sont pas fonction de l'âge et du sexe, mais ils sont en corrélation avec la gravité de la maladie. Résultats selon les types d'épidermolyses; pour celles de type simple, les taux se classent en trois groupes, très bas, bas, normal et leur moyenne est basse aussi, pour celles de type dominant, les taux sont presque normaux, pour celles de type récessif, les taux se classent en deux groupes, normal et bas. Tous les cas, où l'on rencontre des taux de FN bas, sont a l'état évolutif, et l'abaissement de la FN plasmatique est en corrélation inverse avec la gravité (p<0,01).     

浆细胞样树突状细胞和TLR9及其mRNA在银屑病患者皮损中的表达

目的：探讨浆细胞样树突状细胞（Plasmacytoid dendritic cells,PDCs）和toll样受体9（TLR9）在银屑病发病中的表达状态。方法：采用免疫组织化学SP法和逆转录-聚合酶链反应（RT-PCR）方法检测了22例银屑病患者皮肤损害中PDCs和TLR9及其mRNA的表达。15例整形外科患者的皮肤作为正常对照。结果：免疫组化结果显示银屑病组皮损中PDCs、TLR9的表达明显增多,而在正常对照组没有表达;RT-PCR检测显示银屑病皮损中TLR9mRNA的表达明显高于正常对照组（P〈0.01）。结论：银屑病患者皮损中有PDCs浸润,TLR9及其mRNA的表达水平上调,可能与银屑病的发病相关。     

An association between IL-9 and IL-9 receptor gene polymorphisms and atopic dermatitis in a Korean population

Background

The genes encoding IL-9 and IL-9R have recently been implicated in the genetic basis of asthma and allergy. Although studies performed on transgenic and knockout mice have shown conflicting results, no evidence of skin changes has ever been reported in these animals.

Objective

To find association of the SNPs in IL-9 and IL-9R genes and interaction of these genes in atopic dermatitis.

Method

We genotyped 5 SNPs from the IL-9 and IL-9R genes of 1090 subject samples (631 AD patients and 459 normal controls). A luciferase assay was then performed for the rs31563 (−4091G/A) SNP located in the IL-9 gene promoter region.

Result

The rs31563 (−4091G/A) SNP in the IL-9 gene was significantly associated with the AD phenotype, especially allergic-type AD. In the luciferase assay, the rs31563 G construct was observed to have 1.54 times higher activity than the rs31563 A construct. Although no association was found between SNPs in IL-9R gene and AD, the rs3093467 SNP showed association with non-allergic AD. In the gene-gene interaction analysis, we found that IL-9/IL-9R genotype rs31563 GG/rs3093467 TT conveyed a greater risk for AD phenotype development.

Conclusion

Significant evidence exists to suggest that the rs31563 SNP (−4091G/A) located in the IL-9 gene is associated with an increased susceptibility to AD. Similarly, the rs3093467 SNP in IL-9R gene seems to be associated with an increased risk for developing non-allergic AD. In a subsequent gene-gene interaction analysis, the rs31563 GG/rs3093467 TT genotype combination (IL-9/IL-9R) was found to exert a synergistic effect in the development of the AD phenotype. As the classes of helper T cells are diverse and the function of IL-9 cytokine has not been fully described, the cutaneous function of IL-9 needs to be further explored in future studies.     

子痫前期患者胎盘、胎膜组织中水通道蛋白9的表达变化

目的：观察水通道蛋白9（AQP9）在子痫前期患者胎盘、胎膜组织中的定位、mRNA及表达变化,分析AQP9在子痫前期发病中发挥的作用。方法：选取本院2014年3月至2015年5月收治的100例孕妇作为研究对象,其中有50例为正常晚期妊娠孕妇,将这50例作为对照组;另外50例为子痫前期孕妇（孕周38~42周）,轻度子痫前期孕妇与重度子痫前期孕妇各25例,将这50例子痫前期患者作为观察组。利用免疫组织化学增强聚合物法对AQP9的定位情况进行测定;利用逆转录-聚合酶链反应对AQP9 mRNA进行检测;利用蛋白印迹技术对蛋白的表达水平进行检测;通过使用凝胶蛋白定量分析软件对蛋白灰度值进行测定。结果：（1）AQP9在羊膜上皮细胞、绒毛膜滋养细胞和合体滋养细胞上定位;（2）两组患者的胎膜组织和胎盘中都有AQP9 mRNA表达;（3）观察组胎膜组织、胎膜中AQP9的灰度值都要高于对照组,差异显著,具有统计学意义（P〈0.05）,而且观察组中重度子痫前期患者胎膜组织、胎膜中AQP9的灰度值要高于轻度子痫前期患者,对比差异,具有统计学意义（P〈0.05）。结论：子痫前期患者AQP9的表达水平得到较大程度的提升,AQP9是造成子痫前期发病的主要因素。     

Biological effects and metabolism of 9-cis-retinoic acid and its metabolite 9,13-di-cis-retinoic acid in HaCaT keratinocytes in vitro: comparison with all-trans-retinoic acid

Abstract 9-cis-Retinoic acid (9cRA), a geometric isomer of all-trans-retinoic acid (atRA), is an endogenous high-affinity ligand for retinoid X receptors and retinoic acid receptors activating them with high potency. 9,13-di-cis-Retinoic acid (9,13dcRA) has been described as a major plasma metabolite of 9cRA. In this study, the biological activity and the metabolism of 9cRA and 9,13dcRA were investigated and compared with those of atRA in a retinol-free culture system of HaCaT keratinocytes. 9cRA exhibited a slightly weaker activity overall than atRA in inhibiting cell proliferation, inducing cellular retinoic acid binding protein II (CRABP II) mRNA levels and upregulating cytokeratin 19 expression. 9,13dcRA regulated HaCaT keratinocyte activity only at the highest concentration tested (10^–6 M). In cultures of HaCaT keratinocytes with atRA and 9cRA, rapid intracellular accumulation of atRA was observed within 2 h, and atRA levels were higher with atRA treatment than with 9cRA treatment. 9,13dcRA remained relatively stable in the medium with intracellular 9,13dcRA levels below the level of detection. Taken together, 9cRA seems to be slightly less potent than atRA in regulating the biological activity of HaCaT keratinocytes, while its metabolite 9,13dcRA is effectively inactive at biologically relevant concentrations. Our data suggest a prodrug/drug relationship between 9cRA and atRA in human keratinocytes. 9,13dcRA seems to be a weaker prodrug of atRA or an inactive metabolic derivative. Received: 6 July 2000 / Revised: 8 September 2000 / Accepted: 25 October 2000     

A novel mutation of keratin 9 in a large Chinese family with epidermolytic palmoplantar keratoderma

BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant inherited skin disorder characterized by diffuse yellow thickening of the skin of the palms and soles, sharply bordered with erythematous margins. Histologically and ultrastructurally, EPPK presents cytolysis of keratinocytes and abnormal aggregation of tonofilaments in the suprabasal layers of the epidermis. To date, 15 different mutations of the keratin 9 gene (KRT9) have been demonstrated to cause most cases of EPPK. OBJECTIVES: To identify the KRT9 mutation in a large Chinese family with EPPK. METHODS: Denaturing high-performance liquid chromatography (DHPLC), DNA sequencing and allele-specific polymerase chain reaction (AS-PCR) were used to screen exon 1 of the KRT9 gene for sequence variations. RESULTS: The DHPLC elution profiles of the DNA fragments amplified from the affected samples differed from those obtained from unaffected individuals, indicating that a sequence variation existed within the analysed fragment of KRT9. DNA sequencing revealed a novel insertion-deletion mutation in the exon 1 of KRT9, 497delAinsGGCT, resulting in the change of tyrosine(166) to tryptophan and leucine (Y166delinsWL). AS-PCR confirmed the mutation was not a common polymorphism. CONCLUSIONS: The results suggest the molecular basis of EPPK in this Chinese family and provide further evidence that mutations in the helix initiation motif of keratin 9 underlie Chinese EPPK.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

SLE患者外周血T、B淋巴细胞TLR9蛋白表达及与临床指标的关系

Objective To study the expressions of Toll-like receptor 9 protein (TLR9) in peripheral B and T lymphocytes in newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) and their relationship with clinical parameters. Methods Blood samples were obtained from 35 newly diag-nosed, untreated patients with SLE and 16 healthy human controls. B, T lymphocytes and TLR9 protein were labeled with fluorescent antibodies, and the expressions of TLR9 protein were detected by flow cytometry in peripheral B and T lymphocytes. The relationship between TLR9 expression and clinical parameters was assessed. Results The proportions of B and T lymphocytes expressing TLR9 in newly diagnosed, untreated patients were (53.94±17.95)% and (49.33 ± 23.30)%, respectively, compared to (29.40 ± 10.54)% and (29.18 ± 14.78)%, respectively, in healthy controls (t = 6.11,3.73, respectively, both P < 0.01). Additionally,the proportion of B lymphocytes expressing TLR9 correlated negatively with SLE disease activity index (SLEDAI)(r = -0.39, P < 0.05), but positively with the level of serum IgA antibody (r = 0.74, P < 0.01).Condnsions The expression of TLR9 is elevated in peripheral T and B lymphocytes from patients with newly diagnosed, untreated SLE, and the proportion of TLR9-expressing B lymphocytes negatively correlates with SLEDAI, but positively correlates with the serum level of IgA antibody.     

Topical 9-cis-retinaldehyde for delivery of 9-cis-retinoic acid in mouse skin

The 9-cis-retinoic acid (9cRA) is an endogenous ligand of retinoid X nuclear receptors (RXRs). Although the epidermis contains five times more RXRs than RARs, little is known on the activity of topical 9cRA. In order to circumvent surface isomerization of topically applied 9cRA into all-trans-retinoic acid (atRA), we used topical 9-cis-retinaldehyde (9cRAL) as a precursor of 9cRA, hypothesizing that keratinocytes would metabolize 9cRAL into 9-cis-retinoic acid (9cRA). Retinoid content was determined by HPLC analysis of mouse tail skin that had been washed after the application of 9cRAL (0.05% for 14 days) to evaluate the metabolites produced within the epidermis. Biologic activities of 9cRAL and atRAL were analysed by assessing hyperplastic and metaplastic responses, by determining epidermal thickness and the levels of mRNAs encoding for specific keratins. atRAL and derived retinoids were found in skin treated with either atRAL or 9cRAL. The metabolite pattern obtained with 9cRAL was similar to that obtained with atRAL except the presence in 9cRAL samples of an unidentified nonpolar metabolite. However, treatment with 9cRAL yielded higher atRAL and lower retinyl ester concentrations. The biologic activities (hyperplastic and metaplastic responses) resulting from topical application of 9cRAL were lower than those induced by atRAL or atRA at similar concentrations. Taken together, these data show that topical 9cRAL does not deliver significant amounts of 9cRA and exerts less biologic activity than atRAL. Contrary to atRAL, 9cRAL does not appear therefore as a pertinent candidate for topical use in humans.