Alopecia of IFN-gamma knockout mouse as a model for disturbance of the hair cycle: a unique arrest of the hair cycle at the anagen phase accompanied by mitosis

Transplantation of Graft Anti-Host Cytotoxic T Lymphocytes Along with Allogeneic Bone Marrow Skips Macrophage-Induced Graft-Versus-Host Disease

Graft-versus-host disease (GVHD) is a physiological response of the graft to allogeneic hosts. However, the effector cells, affected organ(s), and cytokines in the GVHD remain controversially discussed, without having determined a particular cytotoxic activity of the graft against the host. After i.v. injection of C57BL/6 (H-2^b) spleen cells into irradiated BDF1 (H-2^b/d) mice, the hosts developed interferon-gamma (IFN-γ)-dependent bone marrow (BM) GVHD on days 5-17. When H-2D^dK^d transgenic H-2^b lymphoma cells were i.p. inoculated into irradiated, H-2^b splenocyte-transplanted H-2^b/d mice, the infiltration of macrophages cytotoxic against H-2D^dK^d transgenic H-2^b mouse skin epithelia (a GVHD activity) into the peritoneal cavity preceded several days the infiltration of interleukin (IL)-2-dependent cytotoxic T lymphocytes (CTLs) to achieve a graft-versus-leukemia (GVL) effect. In contrast, allogeneic BM transplanted alone into the irradiated mice did not induce GVHD for 44 days, whereas i.v. injection of graft anti-host macrophages or graft anti-host CTLs along with allogeneic BM, respectively, induced GVHD or promoted the GVL effect in the absence of GVHD. These results revealed that macrophage-induced GVHD and the CTL-mediated GVL effect were a set (Th1: IFN-γ/IL-2) response of the graft to allogeneic hosts and leukemia cells, respectively, and that graft T cell activation rather than inhibition skipped GVHD after BM transplantation.

IFN-γ Control of an Effector/Target Combination for Skin Allograft Rejection: Macrophage/Skin Components in Normal Mice or T Cell/Endothelial Cells in IFN-γ-Deficient Mice

Organ, skin, or cell allografts are acutely rejected from normal mice, whereas vascularized organ allografts, but not allografted Meth A cells, are rejected from interferon-γ (IFN-γ)-deficient mice. Here we explored effector/target combinations for i.p. allografted Meth A (cytotoxic T lymphocyte [CTL]-resistant) or RLmale1 (CTL-susceptible) cells into or for BALB/c skin (skin components: CTL resistant) onto normal or IFN-γ-deficient C57BL/6 mice. After allografting, normal mice showed more infiltration but only a little thrombosis/hemorrhage. Monocyte/macrophage MHC receptor (MMR)⁺ macrophages (on days 5-10) and T cell receptor (TCR)⁺ CTLs (on days 7-9) were cytotoxic against Meth A cells or skin components and RLmale1 cells, respectively, and the allografts were rejected. After allografting into IFN-γ-deficient mice, MMR^- macrophages and highly activated TCR⁺ CTLs were induced, and the mice died of hemorrhagic ascites with Meth A cells and more acutely rejected RLmale1 cells. The CTLs on days 4-6 were inactive toward skin components at an in vivo effector/target ratio but injured endothelial cells to cause severe thrombosis/hemorrhage and more acute rejection of skin allografts. These results indicate that IFN-γ-dependent MMR expression was essential for macrophage-mediated cytolysis of allogeneic skin components and that IFN-γ-deficient mice more acutely rejected skin allograft by causing CTL-induced injury to endothelial cells.

An immune regulatory CCT repeat containing oligodeoxynucleotide capable of causing hair loss in male mice

An oligodeoxynucleotide with CCT repeats (CCT ODN) has been found in our previous study to selectively downregulate Toll-like receptor 7/9 (TLR7/9)-mediated immune responses both in vitro and in vivo. In this study, we unexpectedly found that CCT ODN induced severe patchy hair loss around the mouth in male F1 mice (female Balb/c × male C57BL/6) with lupus-like nephritis induced by injecting allogenic lymphocytes and also in male Balb/c mice, but not in female F1 mice and Balb/c mice and either gender of C57BL/6 mice. Increased infiltration of natural killer group 2, member D (NKG2D⁺) cells in hair loss skin and upregulated interferon-gamma (IFN-γ) messenger RNA expression in cultured splenocytes were observed in male Balb/c mice. The CCT ODN-conditioned supernatants of cultured mouse splenocytes caused catagen-like changes to hair follicles (HFs). We hypothesized that the CCT ODN could induce patchy hair loss in the male mice with certain genetic traits by mobilizing NKG2D⁺ cells to HFs and by inducing the production of IFN-γ from immune cells. Taken together these data indicated that a gender and genetic preference of immune-regulatory oligonucleotides is causing unexpected clinical situations such as hair loss.

Alopecia areata profiling shows TH1, TH2, and IL-23 cytokine activation without parallel TH17/TH22 skewing

BACKGROUND

Alopecia areata (AA) is a common T cell-mediated disorder with limited therapeutics. A molecular profile of cytokine pathways in AA tissues is lacking. Although studies have focused on TH1/IFN-γ responses, several observations support a shared genetic background between AA and atopy.

OBJECTIVE

We sought to define the AA scalp transcriptome and associated biomarkers with comparisons with atopic dermatitis (AD) and psoriasis.

METHODS

We performed microarray and RT-PCR profiling of 27 lesional and 17 nonlesional scalp samples from patients with AA for comparison with normal scalp samples (n = 6). AA gene expression was also compared with samples from patients with lesional or nonlesional AD and those with psoriasis. A fold change of greater than 1.5 and a false discovery rate of less than 0.05 were used for differentially expressed genes (DEGs).

RESULTS

We established the AA transcriptomes (lesional vs nonlesional: 734 DEGs [297 upregulated and 437 downregulated]; lesional vs normal: 4230 DEGs [1980 upregulated and 2250 downregulated]), including many upregulated immune and downregulated hair keratin genes. Equally impressive as upregulation in TH1/interferon markers (IFNG and CXCL10/CXCL9) were those noted in TH2 (IL13, CCL18, CCL26, thymic stromal lymphopoietin, and periostin), TH9/IL-9, IL-23 (p40 and p19), and IL-16 mediators (all P < .05). There were no increases in TH17/TH22 markers. Hair keratin (KRT) expressions (ie, KRT86 and KRT85) were significantly suppressed in lesional skin. Greater scalp involvement (>25%) was associated with greater immune and keratin dysregulation and larger abnormalities in nonlesional scalp samples (ie, CXCL10 and KRT85).

CONCLUSIONS

Our data associate the AA signature with TH2, TH1, IL-23, and IL-9/TH9 cytokine activation, suggesting consideration of anti-TH2, anti-TH1, and anti-IL-23 targeting strategies. Similar to psoriasis and AD, clinical trials with selective antagonists are required to dissect key pathogenic pathways.

Mycophenolate antagonizes IFN-γ-induced catagen-like changes via β-catenin activation in human dermal papilla cells and hair follicles

Recently, various immunosuppressant drugs have been shown to induce hair growth in normal hair as well as in alopecia areata and androgenic alopecia; however, the responsible mechanism has not yet been fully elucidated. In this study, we investigate the influence of mycophenolate (MPA), an immunosuppressant, on the proliferation of human dermal papilla cells (hDPCs) and on the growth of human hair follicles following catagen induction with interferon (IFN)-γ. IFN-γ was found to reduce β-catenin, an activator of hair follicle growth, and activate glycogen synthase kinase (GSK)-3β, and enhance expression of the Wnt inhibitor DKK-1 and catagen inducer transforming growth factor (TGF)-β2. IFN-γ inhibited expression of ALP and other dermal papillar cells (DPCs) markers such as Axin2, IGF-1, and FGF 7 and 10. MPA increased β-catenin in IFN-γ-treated hDPCs leading to its nuclear accumulation via inhibition of GSK3β and reduction of DKK-1. Furthermore, MPA significantly increased expression of ALP and other DPC marker genes but inhibited expression of TGF-β2. Therefore, we demonstrate for the first time that IFN-γ induces catagen-like changes in hDPCs and in hair follicles via inhibition of Wnt/β-catenin signaling, and that MPA stabilizes β-catenin by inhibiting GSK3β leading to increased β-catenin target gene and DP signature gene expression, which may, in part, counteract IFN-γ-induced catagen in hDPCs.

Differential Susceptibility of Cells Expressing Allogeneic MHC or Viral Antigen to Killing by Antigen-Specific CTL

CD8(+) cytotoxic T lymphocytes (CTLs) generated by immunization with allogeneic cells or viral infection are able to lyse allogeneic or virally infected in vitro cells (e.g., lymphoma and mastocytoma). In contrast, it is reported that CD8(+) T cells are not essential for allograft rejection (e.g., heart and skin), and that clearance of influenza or the Sendai virus from virus-infected respiratory epithelium is normal or only slightly delayed after a primary viral challenge of CD8-knockout mice. To address this controversy, we generated H-2(d)-specific CD8(+) CTLs by a mixed lymphocyte culture and examined the susceptibility of a panel of H-2(d) cells to CTL lysis. KLN205 squamous cell carcinoma, Meth A fibrosarcoma, and BALB/c skin components were found to be resistant to CTL-mediated lysis. This resistance did not appear to be related to a reduced expression of MHC class I molecules, and all these cells could block the recognition of H-2(d) targets by CTLs in cold target inhibition assays. We extended our observation by persistently infecting the same panel of cell lines with defective-interfering Sendai virus particles. The Meth A and KLN205 lines infected with a variant Sendai virus were resistant to lysis by Sendai virus-specific CTLs. The Sendai virus-infected Meth A and KLN205 lines were able to block the lysis of Sendai virus-infected targets by CTLs in cold target inhibition assays. Taken together, these results suggest that not all in vivo tissues may be sensitive to CTL lysis.

Keratin 17 modulates hair follicle cycling in a TNFalpha-dependent fashion

Mammalian hair follicles cycle between stages of rapid growth (anagen) and metabolic quiescence (telogen) throughout life. Transition from anagen to telogen involves an intermediate stage, catagen, consisting of a swift, apoptosis-driven involution of the lower half of the follicle. How catagen is coordinated, and spares the progenitor cells needed for anagen re-entry, is poorly understood. Keratin 17 (K17)-null mice develop alopecia in the first week post-birth, correlating with hair shaft fragility and untimely apoptosis in the hair bulb. Here we show that this abnormal apoptosis reflects premature entry into catagen. Of the proapoptotic challenges tested, K17-null skin keratinocytes in primary culture are selectively more sensitive to TNFalpha. K17 interacts with TNF receptor 1 (TNFR1)-associated death domain protein (TRADD), a death adaptor essential for TNFR1-dependent signal relay, suggesting a functional link between this keratin and TNFalpha signaling. The activity of NF-kappaB, a downstream target of TNFalpha, is increased in K17-null skin. We also find that TNFalpha is required for a timely anagen-catagen transition in mouse pelage follicles, and that its ablation partially rescues the hair cycling defect of K17-null mice. These findings identify K17 and TNFalpha as two novel and interdependent regulators of hair cycling.

Regulation of Hair Regrowth in Alopecic Site of IFN-γ−/−Mice by Macrophages Infiltrating into Allograft in IFN-γ+/+Mice

We previously demonstrated that around 6 weeks of age, most of the interferon-gamma (IFN-gamma)-/- C57BL/6 mice began to lose morphogenesis-derived hairs in their dorsal and occipital areas and that hair regrowth in the alopecic site was induced by intraperitoneal (i.p.) injection of IFN-gamma and allogeneic Meth A cells. Here, we explored the IFN-gamma mRNA expression in the cells infiltrating into allograft in IFN-gamma(+)/(+) mice by RT-PCR and adoptively transferred specific antigen-minus infiltrates into IFN-gamma-/- mice to assess the hair regrowth inducibility. IFN- gamma mRNA was expressed in the infiltrates on days 3-8 after allografting, with a peak on day 3 or 4, and CD4(+) and F4/80(+) cells were the major producers of IFN-gamma. All infiltrates on day 3 induced hair regrowth, whereas those on days 0-2 or 4-8 were ineffective or partially effective, respectively. The removal of F4/80(+) macrophages from all infiltrates failed to induce hair regrowth, whereas the removal of Ly-6C(+) macrophages rather accelerated the hair regrowth. These results showed that F4/80(+), Ly-6C(+), and CD4(+) and F4/80(+) cells were stimulatory, inhibitory, and IFN-gamma-producing cells, respectively, in the regulation of hair regrowth.

Interferon-gamma is a potent inducer of catagen-like changes in cultured human anagen hair follicles

BACKGROUND

Interferon (IFN)-gamma appears to be an important hair cycle modulator in mice. It is unclear whether it has similar hair growth modulatory functions in human hair follicles.

OBJECTIVES

To study whether IFN-gamma can be exploited to modulate the growth, pigmentation and/or cycling of organ-cultured human anagen scalp hair follicles, as an in vitro indicator system for how IFN-gamma affects human hair growth in vivo. This was correlated with the hair follicle expression patterns of IFN-gamma receptors alpha and beta. In addition, we wanted to establish a new, simple tool for the rapid experimental induction of catagen in vitro.

METHODS

Normal human scalp hair follicles in the anagen VI stage of the hair cycle were cultured according to the method of Philpott et al., with or without IFN-gamma (50-1000 IU mL(-1)). Hair shaft elongation and pigmentation changes were measured, complemented by quantitative histomorphometry to assess changes in hair follicle cycling (hair cycle score), proliferation (Ki-67), melanogenesis (Masson-Fontana) and apoptosis (TUNEL). IFN-gamma receptors were also localized by immunofluorescence and EnVision technique. As transforming growth factor (TGF)-beta2 is a recognized key inducer of catagen in human hair follicles, TGF-beta2 expression was investigated by tyramide signal amplification and reverse transcription-polymerase chain reaction in anagen hair follicles treated with vehicle (phosphate-buffered saline) or IFN-gamma.

RESULTS

IFN-gamma rapidly inhibited hair elongation in cultured human anagen hair follicles and induced morphological signs of catagen transformation after only 4 days of culture, i.e. faster than with other reported catagen-inducers (e.g. TGF-beta2). Proliferation was inhibited, apoptosis was increased and follicular melanogenesis was switched off in hair bulb keratinocytes treated in situ with IFN-gamma. Anagen hair follicles displayed strong IFN-gamma receptor alpha-like immunoreactivity, while the immunoreactivity for IFN-gamma receptor beta in the hair matrix was only weak. TGF-beta2 immunoreactivity and mRNA transcript levels were enhanced in hair follicles treated with IFN-gamma.

CONCLUSIONS

These data suggest that IFN-gamma is a potent catagen inducer in normal human scalp hair follicles, which express cognate receptors, and show that IFN-gamma administration offers an excellent tool for experimental catagen induction in organ-cultured human hair follicles. This catagen induction probably occurs at least in part via upregulation of the recognized catagen-stimulatory growth factor TGF-beta2.

Induction of hair regrowth in the alopecia site of IFN-gamma knockout mice by allografting and IFN-gamma injection into the transplantation site

We previously demonstrated that around 6 weeks of age most of the interferon-gamma (IFN-gamma)(-/-) but none of the IFN-gamma(+/+) C57BL/6 mice began to lose hair in their dorsal or occipital areas or both and that a single s.c. injection of IFN-gamma into IFN-gamma(-/-) mice at 3 but not at 8 weeks of age (or later) could protect all the mice from alopecia. Here, we report hair regrowth in the alopecia site of IFN-gamma(-/-) mice at 8 weeks of age (or later) by the combination of IFN-gamma and allografting. Skin or tumor allografting and IFN-gamma injections into the transplantation site induced hair regrowth in the alopecia site of IFN-gamma(-/-) mice at 8-66 weeks of age, whereas IFN-gamma injections into the hairless site or allografting alone was ineffective in causing the hair regrowth. Histologic findings showed that the hair cycle in the region of alopecia of IFN-gamma(-/-) mice was blocked at the anagen stage and that in the IFN-gamma(-/-) mice treated with IFN-gamma and allografting, the cycle was at the telogen stage. The therapeutic effects were maintained for >1 year.

Cellular origin of IFN-gamma essential for hair cycle in normal skin

Hair growth abnormalities in mice usually are accompanied by histologic abnormalities as well. Recently, however, we reported a mouse model in which an arrest of the hair cycle and diffuse shedding of the hair without pathologic features induced alopecia in interferon-gamma(-/-) (IFN-gamma(-/-)) C57BL/6 (B6) mice. Here, we explored the cellular origin of IFN-gamma. When bone marrow from IFN-gamma(-/-) B6 mice was transplanted into lethally irradiated IFN-gamma(+/+) B6 mice, the level of IFN-gamma mRNA expression in the skin or peripheral blood mononuclear cells (PBMCs) of recipient mouse was markedly reduced, suggesting that IFN-gamma is normally produced by bone marrow-derived cells. Although severe combined immunodeficiency (SCID) mice lack mature T cells and B cells, IFN-gamma-dependent hair regrowth was induced in SCID mice by depilation, which caused alopecia in IFN-gamma(-/-) B6 mice. Consistently, IFN-gamma mRNA expression in the skin or PBMC from SCID mice was comparable to that from their genetic counterpart (BALB/c mice), suggesting IFN-gamma production by non-T cells. RT-PCR analyses after separation of PBMC from SCID mice into eight fractions by a cell sorter revealed that Mac-1(+) cells were the major origin of IFN-gamma.