Jane E. Cerise

Alopecia areata is driven by cytotoxic T lymphocytes and is reversed by JAK inhibition

Alopecia areata (AA) is a common autoimmune disease resulting from damage of the hair follicle by T cells. The immune pathways required for autoreactive T cell activation in AA are not defined limiting clinical development of rational targeted therapies. Genome-wide association studies (GWAS) implicated ligands for the NKG2D receptor (product of the KLRK1 gene) in disease pathogenesis. Here, we show that cytotoxic CD8+NKG2D+ T cells are both necessary and sufficient for the induction of AA in mouse models of disease. Global transcriptional profiling of mouse and human AA skin revealed gene expression signatures indicative of cytotoxic T cell infiltration, an interferon-γ (IFN-γ) response and upregulation of several γ-chain (γc) cytokines known to promote the activation and survival of IFN-γ–producing CD8+NKG2D+ effector T cells. Therapeutically, antibody-mediated blockade of IFN-γ, interleukin-2 (IL-2) or interleukin-15 receptor β (IL-15Rβ) prevented disease development, reducing the accumulation of CD8+NKG2D+ T cells in the skin and the dermal IFN response in a mouse model of AA. Systemically administered pharmacological inhibitors of Janus kinase (JAK) family protein tyrosine kinases, downstream effectors of the IFN-γ and γc cytokine receptors, eliminated the IFN signature and prevented the development of AA, while topical administration promoted hair regrowth and reversed established disease. Notably, three patients treated with oral ruxolitinib, an inhibitor of JAK1 and JAK2, achieved near-complete hair regrowth within 5 months of treatment, suggesting the potential clinical utility of JAK inhibition in human AA.

Microenvironmental reprogramming by three-dimensional culture enables dermal papilla cells to induce de novo human hair-follicle growth

Significance Growth of de novo hair follicles in adult skin occurs by a process known as hair neogenesis. One way of initiating neogenesis is to place dermal papillae isolated from the hair follicle in contact with an overlying epidermis where they reprogram the epidermis to adopt a follicular fate. This approach, however, has not been successful using cultured human dermal papilla cells in human skin because the cells lose their ability to induce hair growth after expansion in vitro. In this paper, we demonstrate that by manipulating cell culture conditions to establish three-dimensional papilla spheroids, we restore dermal papilla inductivity. We also use several systems biology approaches to gain a comprehensive understanding of the molecular mechanisms that underlie this regenerative process. De novo organ regeneration has been observed in several lower organisms, as well as rodents; however, demonstrating these regenerative properties in human cells and tissues has been challenging. In the hair follicle, rodent hair follicle-derived dermal cells can interact with local epithelia and induce de novo hair follicles in a variety of hairless recipient skin sites. However, multiple attempts to recapitulate this process in humans using human dermal papilla cells in human skin have failed, suggesting that human dermal papilla cells lose key inductive properties upon culture. Here, we performed global gene expression analysis of human dermal papilla cells in culture and discovered very rapid and profound molecular signature changes linking their transition from a 3D to a 2D environment with early loss of their hair-inducing capacity. We demonstrate that the intact dermal papilla transcriptional signature can be partially restored by growth of papilla cells in 3D spheroid cultures. This signature change translates to a partial restoration of inductive capability, and we show that human dermal papilla cells, when grown as spheroids, are capable of inducing de novo hair follicles in human skin.

Reversal of Alopecia Areata Following Treatment With the JAK1/2 Inhibitor Baricitinib.

Background Alopecia areata (AA) is an autoimmune disease resulting in hair loss with devastating psychosocial consequences. Despite its high prevalence, there are no FDA-approved treatments for AA. Prior studies have identified a prominent interferon signature in AA, which signals through JAK molecules. Methods A patient with AA was enrolled in a clinical trial to examine the efficacy of baricitinib, a JAK1/2 inhibitor, to treat concomitant CANDLE syndrome. In vivo, preclinical studies were conducted using the C3H/HeJ AA mouse model to assess the mechanism of clinical improvement by baricitinib. Findings The patient exhibited a striking improvement of his AA on baricitinib over several months. In vivo studies using the C3H/HeJ mouse model demonstrated a strong correlation between resolution of the interferon signature and clinical improvement during baricitinib treatment. Interpretation Baricitinib may be an effective treatment for AA and warrants further investigation in clinical trials.

Safety and efficacy of the JAK inhibitor tofacitinib citrate in patients with alopecia areata

BACKGROUND Alopecia areata (AA) is an autoimmune disease characterized by hair loss mediated by CD8+ T cells. There are no reliably effective therapies for AA. Based on recent developments in the understanding of the pathomechanism of AA, JAK inhibitors appear to be a therapeutic option; however, their efficacy for the treatment of AA has not been systematically examined. METHODS This was a 2-center, open-label, single-arm trial using the pan-JAK inhibitor, tofacitinib citrate, for AA with >50% scalp hair loss, alopecia totalis (AT), and alopecia universalis (AU). Tofacitinib (5 mg) was given twice daily for 3 months. Endpoints included regrowth of scalp hair, as assessed by the severity of alopecia tool (SALT), duration of hair growth after completion of therapy, and disease transcriptome. RESULTS Of 66 subjects treated, 32% experienced 50% or greater improvement in SALT score. AA and ophiasis subtypes were more responsive than AT and AU subtypes. Shorter duration of disease and histological peribulbar inflammation on pretreatment scalp biopsies were associated with improvement in SALT score. Drug cessation resulted in disease relapse in 8.5 weeks. Adverse events were limited to grade I and II infections. An AA responsiveness to JAK/STAT inhibitors score was developed to segregate responders and nonresponders, and the previously developed AA disease activity index score tracked response to treatment. CONCLUSIONS At the dose and duration studied, tofacitinib is a safe and effective treatment for severe AA, though it does not result in a durable response. Transcriptome changes reveal unexpected molecular complexity within the disease. TRIAL REGISTRATION ClinicalTrials.gov NCT02197455 and NCT02312882. FUNDING This work was supported by the US Department of Veterans Affairs Office of Research and Development, National Institute of Arthritis and Musculoskeletal and Skin Diseases National Institutes of Health grant R01 AR47223 and U01 AR67173, the National Psoriasis Foundation, the Swedish Society of Medicine, the Fernström Foundation, the Locks of Love Foundation, the National Alopecia Areata Foundation, and the Ranjini and Ajay Poddar Resource Fund for Dermatologic Diseases Research.

Induced pluripotent stem cells from human revertant keratinocytes for the treatment of epidermolysis bullosa

Epidermolysis bullosa patient–specific iPSCs were generated from spontaneously corrected revertant keratinocytes for skin reconstitution. “Natural Gene Therapy” for Rare, Genetic Skin Disease Epidermolysis bullosa (EB) is a rare, inherited skin disorder that causes such severe blistering that patients are often relegated to a delicate life in bandages. Like a patchwork quilt, the skin of a patient with EB can consist of both mutated skin cells (which cause the disease) and spontaneously genetically corrected “normal” cells; this patchwork phenomenon is known as revertant mosaicism. In a new study, Umegaki-Arao and colleagues demonstrated that these revertant cells could be used to generate healthy skin, representing a possible cell therapy for patients with EB who have no treatment options. The authors took revertant keratinocytes (skin cells) from a patient with junctional EB, who have mutations in the gene expressing type XVII collagen. These revertant keratinocytes were used to generate induced pluripotent stem cells, which, in turn, could be differentiated into a keratinocyte lineage that created normal-looking skin layers not only in vitro but also in vivo in mice. Because the cells already expressed type XVII collagen, there was no need for genetic correction, thus avoiding many of the pitfalls that gene and cell therapies face during translation to the clinic. Revertant mosaicism is a naturally occurring phenomenon involving spontaneous correction of a pathogenic gene mutation in a somatic cell. It has been observed in several genetic diseases, including epidermolysis bullosa (EB), a group of inherited skin disorders characterized by blistering and scarring. Induced pluripotent stem cells (iPSCs), generated from fibroblasts or keratinocytes, have been proposed as a treatment for EB. However, this requires genome editing to correct the mutations, and, in gene therapy, efficiency of targeted gene correction and deleterious genomic modifications are still limitations of translation. We demonstrate the generation of iPSCs from revertant keratinocytes of a junctional EB patient with compound heterozygous COL17A1 mutations. These revertant iPSCs were then differentiated into naturally genetically corrected keratinocytes that expressed type XVII collagen (Col17). Gene expression profiling showed a strong correlation between gene expression in revertant iPSC–derived keratinocytes and the original revertant keratinocytes, indicating the successful differentiation of iPSCs into the keratinocyte lineage. Revertant-iPSC keratinocytes were then used to create in vitro three-dimensional skin equivalents and reconstitute human skin in vivo in mice, both of which expressed Col17 in the basal layer. Therefore, revertant keratinocytes may be a viable source of spontaneously gene-corrected cells for developing iPSC-based therapeutic approaches in EB.

Oral ruxolitinib induces hair regrowth in patients with moderate-to-severe alopecia areata

BACKGROUND. Alopecia areata (AA) is a common autoimmune disease with a lifetime risk of 1.7%; there are no FDA-approved treatments for AA. We previously identified a dominant IFN-γ transcriptional signature in cytotoxic T lymphocytes (CTLs) in human and mouse AA skin and showed that treatment with JAK inhibitors induced durable hair regrowth in mice by targeting this pathway. Here, we investigated the use of the oral JAK1/2 inhibitor ruxolitinib in the treatment of patients with moderate-to-severe AA. METHODS. We initiated an open-label clinical trial of 12 patients with moderate-to-severe AA, using oral ruxolitinib, 20 mg twice per day, for 3-6 months of treatment followed by 3 months follow-up off drug. The primary endpoint was the proportion of subjects with 50% or greater hair regrowth from baseline to end of treatment. RESULTS. Nine of twelve patients (75%) demonstrated a remarkable response to treatment, with average hair regrowth of 92% at the end of treatment. Safety parameters remained largely within normal limits, and no serious adverse effects were reported. Gene expression profiling revealed treatment-related downregulation of inflammatory markers, including signatures for CTLs and IFN response genes and upregulation of hair-specific markers. CONCLUSION. In this pilot study, 9 of 12 patients (75%) treated with ruxolitinib showed significant scalp hair regrowth and improvement of AA. Larger randomized controlled trials are needed to further assess the safety and efficacy of ruxolitinib in the treatment of AA. TRIAL REGISTRATION. Clinicaltrials.gov NCT01950780. FUNDING. Locks of Love Foundation, the Alopecia Areata Initiative, NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), and the Irving Institute for Clinical and Translational Research/Columbia University Medical Center Clinical and Translational Science Award (CUMC CTSA).

Pharmacologic inhibition of JAK-STAT signaling promotes hair growth.

Topical treatment of mouse and human skin with small-molecule inhibitors of the JAK-STAT pathway results in hair growth. Several forms of hair loss in humans are characterized by the inability of hair follicles to enter the growth phase (anagen) of the hair cycle after being arrested in the resting phase (telogen). Current pharmacologic therapies have been largely unsuccessful in targeting pathways that can be selectively modulated to induce entry into anagen. We show that topical treatment of mouse and human skin with small-molecule inhibitors of the Janus kinase (JAK)–signal transducer and activator of transcription (STAT) pathway results in rapid onset of anagen and subsequent hair growth. We show that JAK inhibition regulates the activation of key hair follicle populations such as the hair germ and improves the inductivity of cultured human dermal papilla cells by controlling a molecular signature enriched in intact, fully inductive dermal papillae. Our findings open new avenues for exploration of JAK-STAT inhibition for promotion of hair growth and highlight the role of this pathway in regulating the activation of hair follicle stem cells.

Treatment of an alopecia areata patient with tofacitinib results in regrowth of hair and changes in serum and skin biomarkers

Department of Dermatology, Columbia University, New York, NY, USA Correspondence: Julian Mackay-Wiggan, MD, MS, Department of Dermatology, Columbia University, 161 Fort Washington Ave, 12 Floor, New York, NY 10032, USA, Tel: +1 (212) 305-6953, Fax: +1 (212) 305-0286, e-mail: jc992@columbia.edu Angela M. Christiano, PhD, Department of Dermatology, Columbia University, 1150 St. Nicholas Ave., 3 Floor, New York, NY 10032, USA, Tel: +1 (212) 851-4800, Fax: +1 (212) 851-4810, e-mail: amc65@columbia.edu Drs. Jabbari and Nguyen contributed equally to this work. Drs. Mackay and Christiano jointly supervised this work.

Molecular signatures define alopecia areata subtypes and transcriptional biomarkers

Alopecia areata (AA) is an autoimmune disease typified by nonscarring hair loss with a variable clinical course. In this study, we conducted whole genome gene expression analysis of 96 human scalp skin biopsy specimens from AA or normal control subjects. Based on gene expression profiling, samples formed distinct clusters based on the presence or absence of disease as well as disease phenotype (patchy disease compared with alopecia totalis or universalis). Differential gene expression analysis allowed us to robustly demonstrate graded immune activity in samples of increasing phenotypic severity and generate a quantitative gene expression scoring system that classified samples based on interferon and cytotoxic T lymphocyte immune signatures critical for disease pathogenesis.

CXCR3 Blockade Inhibits T Cell Migration into the Skin and Prevents Development of Alopecia Areata

Alopecia areata (AA) is an autoimmune disease of the hair follicle that results in hair loss of varying severity. Recently, we showed that IFN-γ–producing NKG2D+CD8+ T cells actively infiltrate the hair follicle and are responsible for its destruction in C3H/HeJ AA mice. Our transcriptional profiling of human and mouse alopecic skin showed that the IFN pathway is the dominant signaling pathway involved in AA. We showed that IFN-inducible chemokines (CXCL9/10/11) are markedly upregulated in the skin of AA lesions, and further, that the IFN-inducible chemokine receptor, CXCR3, is upregulated on alopecic effector T cells. To demonstrate whether CXCL9/10/11 chemokines were required for development of AA, we treated mice with blocking Abs to CXCR3, which prevented the development of AA in the graft model, inhibiting the accumulation of NKG2D+CD8+ T cells in the skin and cutaneous lymph nodes. These data demonstrate proof of concept that interfering with the Tc1 response in AA via blockade of IFN-inducible chemokines can prevent the onset of AA. CXCR3 blockade could be approached clinically in human AA with either biologic or small-molecule inhibition, the latter being particularly intriguing as a topical therapeutic.