HDAC activity is essential for maintaining the self-renewal and pluripotency of MSCs.

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Mesenchymal stem cells (MSCs) have been proven to be therapeutically effective against atopic dermatitis (AD) in preclinical studies. However, the safety and efficacy of MSCs against AD have not yet been investigated in a clinical study. To establish the safety and efficacy of human umbilical cord blood-derived MSCs (hUCB-MSCs) in AD, 34 adult patients with moderate-tosevere AD were enrolled in two phase trials with a follow-up for 1 month and 3 months, respectively. Patients were randomly allocated to receive low dose (2.5 3 10 7 ) or high dose (5.0 3 10 7 ) of hUCB-MSCs subcutaneously. An Eczema Area and Severity Index (EASI) score, Investigator's Global Assessment (IGA) score, Severity Scoring for Atopic Dermatitis (SCORAD) score, adverse effect assessments, and serum biomarker levels were evaluated as end points. A single treatment of hUCB-MSCs resulted in dose-dependent improvements in AD manifestation. Fifty-five percent of patients in high dose hUCB-MSC-treated group showed a 50% reduction in the EASI score. The IGA score and SCORAD score decreased by 33% and 50%, respectively, in high dose-treated group. Particularly, the administration of high dose hUCB-MSCs reduced the pruritus score by 58%. The serum IgE levels and number of blood eosinophils were downregulated by the treatment. No serious adverse events occurred, and none of the patients discontinued the trial due to adverse events. This is the first report to demonstrate a marked improvement of AD features with cell therapeutics. These data suggest that the infusion of hUCB-MSCs might be an effective therapy for patients with moderate-to-severe AD. STEM CELLS 2017;35:248-255 SIGNIFICANCE STATEMENTAtopic dermatitis (AD) is a chronic and relapsing skin disease which has become a major public health issue. The current clinical therapy against AD has been reported to be limited in its efficacy and often accompanied by side effects. In this study, we report the efficacy and safety of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in patients with moderate-to-severe atopic dermatitis (AD) as a promising alternative therapy. This first-in-class clinical study shows that single subcutaneous injection of hUCB-MSCs improves disease symptoms based on the evaluation of various parameters including EASI, IGA, and SCORAD score without noteworthy adverse events.

Based on immunomodulatory actions of human umbilical cord blood‐derived mesenchymal stem cells (hUCB‐MSCs), in vitro or preclinical studies of hUCB‐MSCs have been conducted extensively in rheumatoid arthritis (RA). However, few human trials have investigated the outcomes of hUCB‐MSC infusions. The CURE‐iv trial was a phase I, uncontrolled, open label trial for RA patients with moderate disease activity despite treatment with methotrexate. The patients received a single intravenous infusion of 2.5 × 107, 5 × 107, or 1 × 108 cells of hUCB‐MSCs for 30 minutes, three patients in each cluster, with an increment of cell numbers when there was no dose‐limited adverse event. Clinical and safety assessments were performed during the study period, and serum cytokines were measured at baseline and 24 hours after the infusion. Out of 11 screened RA patients, 9 were enrolled. The participants were predominantly female (78%) and the mean age was 57.4 years. The mean disease duration was 9.5 years, and baseline 28‐joint disease activity score (DAS28; using erythrocyte sedimentation rate) was 4.53. There was no major toxicity in all clusters up to 4 weeks after the infusion. Serum erythrocyte sedimentation rate changes at 4 weeks (n = 9) were −7.9 ± 10.4 (p = .0517) and DAS28 changes were −1.60 ± 1.57 (p = .0159). Reduced levels of IL‐1β, IL‐6, IL‐8, and TNF‐α at 24 hours were observed in the cluster infused with 1 × 108 MSCs. This phase Ia hUCB‐MSC infusion trial for established RA patients revealed no short‐term safety concerns. Stem Cells Translational Medicine 2018

Cellular senescence involves a reduction in adult stem cell self-renewal, and epigenetic regulation of gene expression is one of the main underlying mechanisms. Here, we observed that the cellular senescence of human umbilical cord blood-derived multipotent stem cells (hUCB-MSCs) caused by inhibition of histone deacetylase (HDAC) activity leads to down-regulation of high mobility group A2 (HMGA2) and, on the contrary, to up-regulation of p16INK4A, p21CIP1/WAF1 and p27KIP1. We found that let-7a1, let-7d, let-7f1, miR-23a, miR-26a and miR-30a were increased during replicative and HDAC inhibitor-mediated senescence of hUCB-MSCs by microRNA microarray and real-time quantitative PCR. Furthermore, the configurations of chromatins beading on these miRNAs were prone to transcriptional activation during HDAC inhibitor-mediated senescence. We confirmed that miR-23a, miR-26a and miR-30a inhibit HMGA2 to accelerate the progress of senescence. These findings suggest that HDACs may play important roles in cellular senescence by regulating the expression of miRNAs that target HMGA2 through histone modification.Electronic supplementary materialThe online version of this article (doi:10.1007/s00018-010-0457-9) contains supplementary material, which is available to authorized users.