A preliminary examination of the role of NFAT 3 in human skin, cultured keratocytes and dermal fibroblasts

Recent knowledge of NFATc4 in oncogenesis and cancer prognosis

Nuclear factor of activated T-cells, cytoplasmic 4 (NFATc4), a transcription factor of NFAT family, which is activated by Ca²⁺/calcineurin signaling. Recently, it is reported that aberrantly activated NFATc4 participated and modulated in the initiation, proliferation, invasion, and metastasis of various cancers (including cancers of the lung, breast, ovary, cervix, skin, liver, pancreas, as well as glioma, primary myelofibrosis and acute myelocytic leukemia). In this review, we cover the latest knowledge on NFATc4 expression pattern, post-translational modification, epigenetic regulation, transcriptional activity regulation and its downstream targets. Furthermore, we perform database analysis to reveal the prognostic value of NFATc4 in various cancers and discuss the current unexplored areas of NFATc4 research. All in all, the result from these studies strongly suggest that NFATc4 has the potential as a molecular therapeutic target in multiple human cancer types.

Pharmacogenetics of topical and systemic treatment of psoriasis

Psoriasis is a chronic inflammatory skin disease. The cause of psoriasis is unknown, although genetics may play a key role in its development. Treatment of the disease varies with severity. Topical drugs, such as corticosteroids, coal tar, retinoids and vitamin D analogs, are commonly used to treat mild psoriasis. Phototherapy and systemic drugs, such as calcineurin inhibitors, methotrexate, acitretin and biological drugs, are usually used to treat moderate-to-severe psoriasis. Not all patients respond well to treatment, and some can develop severe adverse effects. Interindividual differences in several genes may explain this variation in response to treatment. Pharmacogenetics and pharmacogenomics can facilitate more personalized medicine and prevent the adverse effects associated with treatment.

Ethyl acetate fraction of Radix rubiae inhibits cell growth and promotes terminal differentiation in cultured human keratinocytes

ETHNOPHARMACOLOGICAL RELEVANCE

In Chinese medicine practice, Radix rubiae, the dry root of Rubia cordifolia L. is commonly used for the treatment of psoriasis.

AIM OF THE STUDY

Psoriasis is a chronic inflammatory skin disorder characterized by hyperproliferation and aberrant differentiation of epidermal keratinocytes. Our previous studies identified Radix rubiae to have potent antiproliferative action on cultured HaCaT keratinocytes and to induce keratinocyte differentiation in mouse tail model. The present study aimed to investigate whether Radix rubiae could also induce terminal differentiation in cultured human keratinocytes.

METHODS AND RESULTS

The cornified envelope (CE) formation assay showed that ethyl acetate (EA) fraction of Radix rubiae significantly accentuated the CE formation, a well-recognized marker of terminal differentiation, in cultured HEK and HaCaT cells in a dose and time dependent manner. Western blot analyses demonstrated that EA fraction of Radix rubiae at a concentration of 3.2μg/ml significantly increased transglutaminase type I and involucrin expression in both HEK and HaCaT keratinocytes after 96 h treatment, a response similar to that of Ca²⁺ positive control. Moreover, the expression level of cytokeratin 5/14, which is specifically related to cell proliferation, was significantly downregulated while terminal differentiation markers cytokeratin 1/10 were markedly increased by Radix rubiae treatment in both HEK and HaCaT cells.

CONCLUSION

The present experimental findings unequivocally confirmed the keratinocyte terminal differentiation promoting capacity of Radix rubiae, and strongly suggest that Radix rubiae is a promising antipsoriatic agent warranting further clinical development for psoriasis treatment.

The direct cellular target of topically applied pimecrolimus may not be infiltrating lymphocytes

BACKGROUND

Topically applied calcineurin inhibitors have been shown to be effective in the treatment of atopic dermatitis. When systemically administered, these agents cause immunosuppression via inhibition of calcineurin in lymphocytes. As topical agents, the mechanism of action is poorly defined.

OBJECTIVES

To test the hypothesis that skin-infiltrating lymphocytes are directly targeted when calcineurin inhibitors are applied to the skin.

METHODS

Ten patients with atopic dermatitis were treated with 1% pimecrolimus cream twice daily to target lesions. Skin biopsies were performed before and 48 h after beginning therapy. We assessed the cellular localization of NFAT1 and NFAT2 as a surrogate measure of intracellular calcineurin activity (e.g. increasing cytoplasmic localization with increasing calcineurin inhibition).

RESULTS

All patients showed a clinical response, at both 48 h and 2 weeks. As previously described, NFAT2 localized to the follicular keratinocytes, and its activation was partially inhibited by topical pimecrolimus. NFAT1 was found to be expressed by follicular and interfollicular keratinocytes, and its mostly nuclear localization was not affected by topical pimecrolimus therapy. Both NFAT1 and NFAT2 were found in the infiltrating lymphocytes. However, using both manual counting as well as an automated method to assess nuclear intensity of NFAT staining, we found that the proportion of infiltrating leucocytes with nuclear ('activated') NFAT did not change following therapy with pimecrolimus.

CONCLUSIONS

Our results suggest that topical pimecrolimus does not act primarily by inhibiting the calcineurin/NFAT axis in lymphocytes but may instead act by other mechanisms, possibly by decreasing NFAT2 activity in follicular keratinocytes.