Intradermal Injection of Bone Marrow Mesenchymal Stromal Cells Corrects Recessive Dystrophic Epidermolysis Bullosa in a Xenograft Model

Mechanism underlying pruritus in recessive dystrophic epidermolysis bullosa: Role of interleukin-31 from mast cells and macrophages

BACKGROUND

Pruritus is a highly burdensome symptom in patients with epidermolysis bullosa, especially recessive dystrophic epidermolysis bullosa (RDEB); however, only a few studies have assessed the molecular pathogenesis of RDEB-associated pruritus. Interleukin (IL)-31 is a key cytokine implicated in pruritus associated with dermatologic diseases such as atopic dermatitis and prurigo nodularis.

OBJECTIVE

To investigate the role and cellular source of IL-31 in RDEB-associated pruritus.

METHODS

Serum and skin samples were obtained from 11 RDEB patients and 11 healthy controls. Pruritus visual analogue scale scores were determined. Serum levels of IL-31 and thymic stromal lymphopoietin (TSLP) were examined by enzyme-linked immunosorbent assay (ELISA). The expression of IL-31 and other pruritus mediators in the skin were examined through immunofluorescence staining, and their correlation with pruritus severity was analysed.

RESULTS

Serum IL-31 and TSLP were elevated in RDEB patients. IL-31 expression was increased in RDEB skin and positively correlated with pruritus severity. Most of the IL-31-expressing cells were mast cells, and some were CD206(+) M2-like macrophages. The number of substance P(+) cells was also increased in the patients' skin, and most of them were mast cells. The number of substance P(+) mast cells was correlated with the number of IL-31(+) dermal infiltrates. The number of IL-4Rα- and IL-13-expressing cells and expression of TSLP and periostin increased in RDEB skin, but without a correlation to pruritus score.

CONCLUSION

The increased production of skin IL-31 from mast cells and M2-like macrophages may be the mechanism underlying pruritus in RDEB.

Gene-Modified Blister Fluid-Derived Mesenchymal Stromal Cells for Treating Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a genodermatosis caused by variants in COL7A1-encoded type VII collagen, a major component of anchoring fibrils. In this study, we developed an ex vivo gene therapy for RDEB using autologous mesenchymal stromal cells (MSCs). On the basis of our previous studies, we first attempted to isolate MSCs from the blister fluid of patients with RDEB and succeeded in obtaining cells with a set of MSC characteristics from all 10 patients. We termed these cells blister fluid-derived MSCs. Blister fluid-derived MSCs were genetically modified and injected into skins of type VII collagen-deficient neonatal mice transplanted onto immunodeficient mice, resulting in continuous and widespread expression of type VII collagen at the dermal-epidermal junction, particularly when administered into blisters. When injected intradermally, the efforts were not successful. The gene-modified blister fluid-derived MSCs could be cultured as cell sheets and applied to the dermis with an efficacy equivalent to that of intrablister administration. In conclusion, we successfully developed a minimally invasive and highly efficient ex vivo gene therapy for RDEB. This study shows the successful application of gene therapy in the RDEB mouse model for both early blistering skin and advanced ulcerative lesions.

Availability of mRNA Obtained from Peripheral Blood Mononuclear Cells for Testing Mutation Consequences in Dystrophic Epidermolysis Bullosa

Dystrophic epidermolysis bullosa (DEB) is an inheritable blistering disease caused by mutations in COL7A1, which encodes type VII collagen. To address the issue of genotype-phenotype correlations in DEB, analyzing the consequences of COL7A1 mutations using mRNA is indispensable. Herein we established a novel method for testing the effect of mutations in DEB using COL7A1 mRNA extracted from peripheral blood mononuclear cells (PBMCs). We investigated the consequences of four COL7A1 mutations (c.6573 + 1G > C, c.6216 + 5G > T, c.7270C > T and c.2527C > T) in three Japanese individuals with recessive DEB. The novel method detected the consequences of two recurrent COL7A1 mutations (c.6573 + 1G > C, c.6216 + 5G > T) and a novel COL7A1 mutation (c.7270C > T) accurately. In addition, it detected aberrant splicing resulting from a COL7A1 mutation (c.2527C > T) which was previously reported as a nonsense mutation. Furthermore, we revealed that type VII collagen-expressing cells in PBMCs have similar cell surface markers as mesenchymal stem cells; they were CD105⁺, CD29⁺, CD45^-, and CD34^-, suggesting that a small number of mesenchymal stem cells or mesenchymal stromal cells are circulating in the peripheral blood, which enables us to detect COL7A1 mRNA in PBMCs. Taken together, our novel method for analyzing mutation consequences using mRNA obtained from PBMCs in DEB will significantly contribute to genetic diagnoses and novel therapies for DEB.

Intravenous allogeneic umbilical cord blood-derived mesenchymal stem cell therapy in recessive dystrophic epidermolysis bullosa patients

BACKGROUND

Recessive dystrophic epidermolysis bullosa (RDEB) is an incurable disease that causes severe mucocutaneous fragility due to mutations in COL7A1 (encoding type VII collagen [C7]). In this phase I/IIa trial, we evaluated the safety and possible clinical efficacy of intravenous infusion of allogeneic human umbilical cord blood–derived mesenchymal stem cells (hUCB-MSCs) in patients with RDEB.

METHODS

Four adult and two pediatric patients with RDEB were treated with 3 intravenous injections of hUCB-MSCs (1 × 10⁶ to 3 × 10⁶ cells/kg) every 2 weeks and followed up for 8–24 months after treatment. The primary endpoint was safety. Secondary endpoints related to efficacy included clinical parameters, such as disease severity score, wound assessment, itch and pain score, and quality of life. C7 expression levels and inflammatory infiltrates in the skin, as well as serum levels of inflammatory markers and neuropeptides, were also assessed.

RESULTS

Intravenous hUCB-MSC infusions were well tolerated, without serious adverse events. Improvements in the Birmingham Epidermolysis Bullosa Severity Score, body surface area involvement, blister counts, pain, pruritus, and quality of life were observed with maximal effects at 56–112 days after treatment. hUCB-MSC administration induced M2 macrophage polarization and reduced mast cell infiltration in RDEB skin. Serum levels of substance P were decreased after therapy. Increased C7 expression was observed at the dermoepidermal junction in 1 of 6 patients at day 56.

CONCLUSION

To the best of our knowledge, this is the first clinical trial of systemic administration of allogeneic hUCB-MSCs in patients with RDEB, demonstrating safety and transient clinical benefits.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04520022.

FUNDING

This work was supported by Daewoong Pharmaceutical Co. Ltd. and Kangstem Biotech Co. Ltd.

An Update on the Potential of Mesenchymal Stem Cell Therapy for Cutaneous Diseases

Mesenchymal stem or stromal cells (MSCs) are nonhematopoietic postnatal stem cells with self-renewal, multipotent differentiation, and potent immunomodulatory and anti-inflammatory capabilities, thus playing an important role in tissue repair and regeneration. Numerous clinical and preclinical studies have demonstrated the potential application of MSCs in the treatment of tissue inflammation and immune diseases, including inflammatory skin diseases. Therefore, understanding the biological and immunological characteristics of MSCs is important to standardize and optimize MSC-based regenerative therapy. In this review, we highlight the mechanisms underlying MSC-mediated immunomodulation and tissue repair/regeneration and present the latest development of MSC-based clinical trials on cutaneous diseases.

Cellular therapy options for genetic skin disorders with a focus on recessive dystrophic epidermolysis bullosa

INTRODUCTION

Combinatorial cell and gene therapies for life-threatening inherited skin disorders have shown tremendous potential for preclinical and clinical implementation with significant progress made for recessive dystrophic epidermolysis bullosa (RDEB). To date, various cell lineages including resident skin cells and adult stem cells have been investigated for gene and cell therapy for RDEB reaching the clinical trial stage.

SOURCES OF DATA

Sources of data are key recent literature, ClinicalTrials.gov, Clinicaltrialsregister.eu and pharma press releases.

AREAS OF AGREEMENT

Cell-based gene transfer using autologous patients' cells has demonstrated positive outcomes in preclinical and clinical trials and highlighted the importance of targeting resident skin stem cells to achieve a meaningful long-term effect. Additionally, adult stem cells, such as mesenchymal stromal cells, have the potential to ameliorate systemic manifestations of the disease.

AREAS OF CONTROVERSY

While proven safe, the clinical trials of localized treatment have reported only modest and transient improvements. On the other hand, the risks associated with systemic therapies remain high and should be carefully weighed against the potential benefits. It is unclear to what extent adult stem cells can contribute to skin regeneration/wound healing.

GROWING POINTS

Further research is warranted in order to fulfil the potential of cellular therapies for RDEB. The development of combinatorial gene and cell-based approaches is required to achieve long-term clinical benefits.

AREAS TIMELY FOR DEVELOPING RESEARCH

Induced pluripotent stem cells can potentially provide a valuable source of autologous patient material for cellular therapies. In addition, recent advances in the field of gene editing can overcome hurdles associated with conventional gene addition approaches.

DATA AVAILABILITY STATEMENT

No new data were generated or analysed in support of this review.

Phase I/II open-label trial of intravenous allogeneic mesenchymal stromal cell therapy in adults with recessive dystrophic epidermolysis bullosa

BACKGROUND

Recessive dystrophic epidermolysis bullosa (RDEB) is a hereditary blistering disorder due to a lack of type VII collagen. At present, treatment is mainly supportive.

OBJECTIVES

To determine whether intravenous allogeneic bone marrow-derived mesenchymal stromal/stem cells (BM-MSCs) are safe in RDEB adults and if the cells improve wound healing and quality of life.

METHODS

We conducted a prospective, phase I/II, open-label study recruiting 10 RDEB adults to receive 2 intravenous infusions of BM-MSCs (on day 0 and day 14; each dose 2-4 × 10⁶ cells/kg).

RESULTS

BM-MSCs were well tolerated with no serious adverse events to 12 months. Regarding efficacy, there was a transient reduction in disease activity scores (8/10 subjects) and a significant reduction in itch. One individual showed a transient increase in type VII collagen.

LIMITATIONS

Open-label trial with no placebo.

CONCLUSIONS

MSC infusion is safe in RDEB adults and can have clinical benefits for at least 2 months.

IL-1β-Primed Mesenchymal Stromal Cells Improve Epidermal Substitute Engraftment and Wound Healing via Matrix Metalloproteinases and Transforming Growth Factor-β1

Since the 1980s, deep and extensive skin wounds and burns are treated with autologous split-thickness skin grafts, or cultured epidermal autografts, when donor sites are limited. However, the clinical use of cultured epidermal autografts often remains unsatisfactory because of poor engraftment rates, altered wound healing, and reduced skin functionality. In the past few decades, mesenchymal stromal cells (MSCs) have raised much attention because of their anti-inflammatory, protrophic, and pro-remodeling capacities. More specifically, gingival MSCs have been shown to possess enhanced wound healing properties compared with other tissue sources. Growing evidence also indicates that MSC priming could potentiate therapeutic effects in diverse in vitro and in vivo models of skin trauma. In this study, we found that IL-1β-primed gingival MSCs promoted cell migration, dermal-epidermal junction formation, and inflammation reduction in vitro, as well as improved epidermal substitute engraftment in vivo. IL-1β-primed gingival MSCs had different secretory profiles from naive gingival MSCs, characterized by an overexpression of transforming growth factor-β and matrix metalloproteinase (MMP) pathway agonists. Eventually, MMP-1, MMP-9, and transforming growth factor-β1 appeared to be critically involved in IL-1β-primed gingival MSC mechanisms of action.

Patent landscape of molecular and cellular targeted therapies for recessive dystrophic epidermolysis bullosa

INTRODUCTION

Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a monogenetic inherited genodermatosis associated with deleterious mutations in the gene encoding type VII collagen (COL7A1). COL7A1 is essential for promoting attachment of the epidermis to the dermis, and its dysfunction may lead to generalized mucosal and cutaneous blistering associated to severe deformities. Currently, management of RDEB patients is limited to supportive care, being aimed at treating and preventing common complications associated with this condition. There is a great demand to develop targeted therapies for this devastating disease and RDEB research advances are currently being translated into clinical trials.

AREAS COVERED

Based on the literature and patent search, the authors have grouped the RDEB targeted therapies into five categories: a) cell-based therapies; b) gene therapy; c) protein replacement therapy; d) molecular therapy based on exon skipping; and e) drug-mediated premature termination codon read-through. The patent searching strategy involved inquiring Google and USPTO patent databases to reveal companies and institutions that are active in the area of RDEB targeted therapies.

EXPERT OPINION

The patent landscape related to targeted therapies for RDEB is quite heterogeneous, with each targeted therapeutic approach being associated with its own challenges in achieving robust patent protection and identifying opportunities for future development.

Recent advances in understanding and managing epidermolysis bullosa

Epidermolysis bullosa (EB) is a clinically and genetically heterogeneous skin fragility disorder characterized by trauma-induced skin dissociation and the development of painful wounds. So far, mutations in 20 genes have been described as being associated with more than 30 clinical EB subtypes. The era of whole-exome sequencing has revolutionized EB diagnostics with gene panels being developed in several EB centers and allowing quicker diagnosis and prognostication. With the advances of gene editing, more focus has been placed on gene editing-based therapies for targeted treatment. However, their implementation in daily care will still take time. Thus, a significant focus is currently being placed on achieving a better understanding of the pathogenetic mechanisms of each subtype and using this knowledge for the design of symptom-relief therapies, i.e. treatment options aimed at ameliorating and not curing the disease.