Cyclosporin A-induced hair growth in mice is associated with inhibition of calcineurin-dependent activation of NFAT in follicular keratinocytes

Abstract

One of the most common side effects of treatment with cyclosporin A (CsA) is hypertrichosis. This study shows that calcineurin activity is associated with hair keratinocyte differentiation in vivo, affecting nuclear factor of activated T cells (NFAT1) activity in these cells. Treatment of nude or C57BL/6 depilated normal mice with CsA inhibited the expression of keratinocyte terminal differentiation markers associated with catagen, along with the inhibition of calcineurin and NFAT1 nuclear translocation. This was associated with induction of hair growth in nude mice and retardation of spontaneous catagen induction in depilated normal mice. Furthermore, calcineurin inhibition blocked the expression of p21waf/cip1 and p27kip1, which are usually induced with differentiation. This was also associated with an increase in interleukin-1α expression (nude mice), a decrease in transforming growth factor-β (nude and normal mice), and no change in keratinocyte growth factor expression in the skin. Retardation of catagen in CsA-treated mice was accompanied by significant alterations in apoptosis-related gene product expression in hair follicle keratinocytes. The ratio of the anti-apoptotic Bcl-2 to proapoptotic Bax expression increased, and expression of p53 and interleukin-1β converting enzyme activity decreased. These data provide the first evidence that calcineurin is functionally active in follicular keratinocytes and that inhibition of the calcineurin-NFAT1 pathway in these cells in vivo by CsA enhances hair growth.

Bifurcated converging pathways for high Ca 2 +- and TGFβ-induced inhibition of growth of normal human keratinocytes

“…A promoter construct covering the Sp1 binding sites of the p21 WAF1/CIP1 promoter was activated by high Ca 2ϩ in a calcineurin-dependent manner and NFAT1͞2 was coprecipitated with Sp1. Gafter-Gvili et al (35) showed that cyclosporin A enhanced hair growth in the mouse in vivo and inhibited p21 WAF1/CIP1 induction in cultured follicular keratinocytes. In the present study, we showed that upon exposure of NHK cells to high Ca 2ϩ , NFAT1 was dephosphorylated, translocated into nuclei, and bound to the Sp1-binding site of the genomic p21 WAF1/CIP1 promoter in association with Sp1, replacing KLF16 from it.…”

Calcineurin/Nfatc1 signaling links skin stem cell quiescence to hormonal signaling during pregnancy and lactation

“…To this end, we took advantage of the robust ability of CSA to stimulate hair growth in mice (Paus et al 1989;Gafter-Gvili et al 2003) and alter SC quiescence (Horsley et al 2008) even when follicular SCs are refractory to tissue-level activation signals (Plikus et al 2008). Mice treated with a 3-d course of CSA during the second telogen, a time when HFs are in an extended period of quiescence, lose nuclear Nfatc1 expression within the bulge SC compartment (Fig.…”

“…Nfatc1 activity is directly regulated by the phosphatase calcineurin (CN), which dephosphorylates Nfatc1 to induce its nuclear translocation and transcriptional activity (Rao et al 1997;Horsley and Pavlath 2002). Inactivation of Nfatc1 through skin-specific genetic knockout or treatment with cyclosporine A (CSA), an inhibitor of CN (Mattila et al 1990), results in precocious activation of HF growth in mice (Paus et al 1989;Gafter-Gvili et al 2003;Horsley et al 2008). Nfatc1 inhibition induces hair growth through precocious bulge cell proliferation (Horsley et al 2008), and it is not clear whether Nfatc1 inhibition accelerates bulge cell migration to induce HF growth, as in the native hair cycle (Zhang et al 2009).…”

Treatment of Severe Alopecia Areata: Combination Therapy Using Systemic Cyclosporine A with Low Dose Corticosteroids

“…Oliver et al 9 demonstrated that oral CsA restored hair growth in the Dundee Experimental Bald Rat Model of AA by reducing the mononuclear cell infiltrate around the hair follicles and renewing hair growth. GafterGvili et al 10 reported that CsA-induced hair growth in mice was associated with the inhibition of the calcineurin-dependent activation of NFAT in the follicular keratinocytes. They found that CsA delays the duration of the terminal differentiation of hair follicular keratinocytes and it retards catagen induction.…”

“…Calcineurin regulates the nuclear factor of activated T cells (NFAT) and it also induces T cell activation by regulating the interleukin-2 (IL-2) gene expression and increasing the production of IL-2, which stimulates the secretion of interferon-γ (IFN-γ) 9,10 .…”