Epidermal turnover and iron metabolism in senile lentigo.

Senile lentigo (SL) is a pigmentary disorder associated with disrupted epidermal turnover. Trace minerals in the skin are known to regulate keratinocyte proliferation and differentiation. To clarify the role of iron in SL, we compared the expression of molecules related to iron metabolism between SL lesion (lesion) and the surrounding normal skin (nonlesion). Our results revealed that proteins involved in iron uptake and utilization such as transferrin receptor 1, iron regulatory protein 1, mitoferrin 1, and divalent metal transporter 1 were expressed in the lower epidermis in the nonlesion, while expression of them was also observed in the upper epidermis in the lesion. Ferroportin (FPN), involved in iron export, was expressed in the upper epidermis in the nonlesion, but was only scarcely expressed in the upper epidermis in the lesion. Hepcidin, which promotes FPN degradation, was expressed in the lower epidermis in the nonlesion; however, its expression was also observed in the upper epidermis in the lesion. These changes in the expression of molecules involved in iron uptake/export/utilization might reflect the altered iron utilization state in SL, resulting in disruption of keratinocyte differentiation and disturbing epidermal turnover. Our results suggest that the metabolism of iron in keratinocytes in SL differs from that in the normal epidermis, and these changes could be associated with the abnormal epidermal turnover and decreased melanin excretion in SL.

Atypical Protein Kinase C Isoform, aPKCλ, Is Essential for Maintaining Hair Follicle Stem Cell Quiescence.

The atypical protein kinase C (aPKC)-partition-defective (PAR) complex regulates the formation of tight junctions and apico-basal epithelial polarity. To examine the role of this complex in the epidermis, we generated mutant mice harboring epidermal-specific deletion of aPKCλ (conditional knock-out (cKO)), a major component of the aPKC-PAR complex. The mutant mice exhibited abnormal hair follicle (HF) cycling, progressive losses of pelage hairs and vibrissae, and altered differentiation into the epidermis and sebaceous gland. We found that in the aPKCλ cKO mice HF stem cell (HFSC) quiescence was lost, as revealed by the decreased expression level of quiescence-inducing factors (Fgf18 and Bmp6) produced in Keratin 6-positive bulge stem cells. The loss of quiescence dysregulated the HFSC marker expression and led to the increase in Lrig1-positive cells, inducing hyperplasia of the interfollicular epidermis and sebaceous glands, and drove an increase in Lef1-positive matrix cells, causing a prolonged anagen-like phase. Persistent bulge stem cell activation led to a gradual depletion of CD34- and α6 integrin-positive HFSC reservoirs. These results suggest that aPKCλ regulates signaling pathways implicated in HFSC quiescence.

Specific substance of Maruyama (SSM) suppresses immune responses in atopic dermatitis-like skin lesions in DS-Nh mice by modulating dendritic cell functions.

BACKGROUND: Specific substance of Maruyama (SSM) is a carcinostatic immunotherapeutic agent extracted from Mycobacterium tuberculosis. The efficacy of SSM induced interleukin(IL)-12 and IFN-γ production, and inhibition of IL-4, resulting in a shift from Th2 to Th1 in vivo. OBJECTIVE: The DS-Nh mice are a model of human atopic dermatitis (AD), which spontaneously develop dermatitis under conventional conditions. In this study, to determine whether SSM can prevent the development of skin lesions in a murine model of AD. METHODS: DS-Nh mice were injected with SSM 5 days per week for 11 weeks. Pharmacological, histological and serological studies were performed to investigate the therapeutic effect of SSM for DS-Nh mice. Analysis of cytokines responses to SSM using quantitative RT-PCR and flow cytometry were also performed to evaluate their therapeutic mechanisms in these AD model mice. RESULTS: Clinically, erythema, erosions, excoriation, and edema were observed in DS-Nh mice at 16 weeks of age, which advanced with age. Histologically, the relative number of mast cells increased in DS-Nh mice. SSM treatment alleviated the clinical and histological findings in accord with reduced serum IgE level, and increased IgG2a level. TSLP expression was not induced, but IL-1ß, IL-12, IL-17A, and IFN-γ were induced in SSM-treated DS-Nh mice. Overall, SSM treatments increased the number of activated DCs in lesions. SSM induced CD80, CD86, and MHC class II expression on bone marrow-derived DCs. CONCLUSIONS: SSM enhanced IL-12 production, but suppressed TSLP expression, resulting in a shift from Th2 to Th1 responses. This shift suppressed AD-like skin lesions in a similar fashion as the BCG vaccine. Therefore, SSM may be a useful adjuvant for suppressing skin lesions in AD models.

Combined analysis of cell growth and apoptosis-regulating proteins in HPVs associated anogenital tumors.

BACKGROUND: The clinical course of human papillomavirus (HPV) associated with Bowenoid papulosis and condyloma acuminatum of anogenital tumors are still unknown. Here we evaluated molecules that are relevant to cellular proliferation and regulation of apoptosis in HPV associated anogenital tumors. METHODS: We investigated the levels of telomerase activity, and inhibitor of apoptosis proteins (IAPs) family (c-IAP1, c-IAP2, XIAP) and c-Myc mRNA expression levels in 20 specimens of Bowenoid papulosis and 36 specimens of condyloma acuminatum in anogenital areas. Overall, phosphorylated (p-) AKT, p-ribosomal protein S6 (S6) and p-4E-binding protein 1 (4EBP1) expression levels were examined by immunohistochemistry in anogenital tumors both with and without positive telomerase activity. RESULTS: Positive telomerase activity was detected in 41.7% of Bowenoid papulosis and 27.3% of condyloma acuminatum compared to normal skin (p < 0.001). In contrast, the expression levels of Bowenoid papulosis indicated that c-IAP1, c-IAP2 and XIAP mRNA were significantly upregulated compared to those in both condyloma acuminatum samples (p < 0.001, p < 0.001, p = 0.022, respectively) and normal skin (p < 0.001, p = 0.002, p = 0.034, respectively). Overall, 30% of Bowenoid papulosis with high risk HPV strongly promoted IAPs family and c-Myc but condyloma acuminatum did not significantly activate those genes. Immunohistochemically, p-Akt and p-S6 expressions were associated with positive telomerase activity but not with p-4EBP1 expression. CONCLUSION: Combined analysis of the IAPs family, c-Myc mRNA expression, telomerase activity levels and p-Akt/p-S6 expressions may provide clinically relevant molecular markers in HPV associated anogenital tumors.