Psoriasis (Pso) is a chronic inflammatory skin disease with a genetic predisposition and an assumed autoimmune pathomechanism. Autoantigens, dendritic cells (DCs), and the TNF/IL23/Il17 axis are seemingly the main drivers of this process. However, the difference to other DC-driven immune processes, like in eczematic skin, is insufficiently understood. Multi-antigen analysis (MAA) allows the staining of tissue with 100 antigens and more and provides a deeper insight into pathological processes, using advanced imaging analysis and quantification of topographical allocated processes. Here we used this technology to assess and compare the skin immune infiltrations in Pso, chronic eczema, and healthy controls. Tissue samples from both skin diseases (n = 30) were stained for 63 antigens, including 45 immune markers, and cells were analysed and quantified in both epidermis and dermis. The presence of different types of monocyte-derived DC in the epidermis was the most notable distinction between both skin diseases. While in Pso a monocyte-derived DC (CD14+CD1a+CD11c+) predominated, possibly a Langerhans cell (LC)-like DC, eczema displayed a marker combination of a seemingly more differentiated monocyte-derived DC (CD14+CD63+CD163+), potentially a DC3 cell type.

Induced pluripotent stem cells (iPSCs) are a promising cell source for regenerative medicine. Clinical applications require a large number of functional red blood cells (RBCs), making it essential to ensure the proliferation of actively dividing, nucleated erythroblasts derived from iPSCs. Small molecules can enhance the efficiency and frequency of iPSC-derived cell differentiation. Sirtuin 1, a key enzyme in multiple biological processes, has been implicated in enhancing iPSC-derived cell differentiation. However, the specific effects of Sirtuin 1 on erythroblast proliferation from iPSCs remain unclear. Here, we developed a protocol to examine the effects of Sirtuin 1 on erythroblasts after endothelial-to-hematopoietic transition (EHT). We found that Sirtuin 1 activation increased the frequency of CD71＋CD235a＋ erythroblasts at the early stage after EHT, suggesting a role for Sirtuin 1 in the proliferation of these specified erythroblasts. These findings reveal that Sirtuin 1 activation benefits erythroblast proliferation and could be considered for translational application in large-scale RBC culture.

Beta-hemoglobinopathies are severe genetic diseases caused by mutations affecting the production of the adult β-globin chain. The clinical severity is mitigated by the co-inheritance of mutations that reactivate the production of the fetal β-like γ-globin in adults. However, the epigenetic mechanisms underlying the adult-to-fetal hemoglobin (HbA-to-HbF) switching are still not fully understood. Here, we used epigenome editing technologies to dissect the molecular mechanisms underlying γ- and β-globin gene regulation and to develop novel potential therapeutics for β-hemoglobinopathies. Targeted removal of DNA methylation by dCas9-Tet1 (alone or together with the deposition of histone acetylation by CBP-dCas9) at the fetal promoters led to efficient and durable γ-globin reactivation, demonstrating that DNA methylation is a driver for HbF repression. This strategy, characterized by high specificity and a good safety profile, led to a substantial correction of the pathological phenotype in erythroid cells from patients with sickle cell disease.
© The Author(s) 2025. Published by Oxford University Press on behalf of Nucleic Acids Research.

Sickle cell disease is a devastating blood disorder that originates from a single point mutation in the HBB gene coding for hemoglobin. Here, we develop a GMP-compatible TALEN-mediated gene editing process enabling efficient HBB correction via a DNA repair template while minimizing risks associated with HBB inactivation. Comparing viral versus non-viral DNA repair template delivery in hematopoietic stem and progenitor cells in vitro, both strategies achieve comparable HBB correction and result in over 50% expression of normal adult hemoglobin in red blood cells without inducing β-thalassemic phenotype. In an immunodeficient female mouse model, transplanted cells edited with the non-viral strategy exhibit higher engraftment and gene correction levels compared to those edited with the viral strategy. Transcriptomic analysis reveals that non-viral DNA repair template delivery mitigates P53-mediated toxicity and preserves high levels of long-term hematopoietic stem cells. This work paves the way for TALEN-based autologous gene therapy for sickle cell disease.
© 2024. The Author(s).

The etiopathology of Parkinson's disease has been associated with mitochondrial defects at genetic, laboratory, epidemiological, and clinical levels. These converging lines of evidence suggest that mitochondrial defects are systemic and causative factors in the pathophysiology of PD, rather than being mere correlates. Understanding mitochondrial biology in PD at a granular level is therefore crucial from both basic science and translational perspectives. In a recent study, we investigated mitochondrial alterations in fibroblasts obtained from PD patients assessing mitochondrial function in relation to clinical measures. Our findings demonstrated that the magnitude of mitochondrial alterations parallels disease severity. In this study, we extend these investigations to blood cells and dopamine neurons derived from induced pluripotent stem cells reprogrammed from PD patients. To overcome the inherent metabolic heterogeneity of blood cells, we focused our analyses on metabolically homogeneous, accessible, and expandable erythroblasts. Our results confirm the presence of mitochondrial anomalies in erythroblasts and induced dopamine neurons. Consistent with our previous findings in fibroblasts, we observed that mitochondrial alterations are reversible, as evidenced by enhanced mitochondrial respiration when PD erythroblasts were cultured in a galactose medium that restricts glycolysis. This observation indicates that suppression of mitochondrial respiration may constitute a protective, adaptive response in PD pathogenesis. Notably, this effect was not observed in induced dopamine neurons, suggesting their distinct bioenergetic behavior. In summary, we provide additional evidence for the involvement of mitochondria in the disease process by demonstrating mitochondrial abnormalities in additional cell types relevant to PD. These findings contribute to our understanding of PD pathophysiology and may have implications for the development of novel biomarkers and therapeutic strategies.
© 2024. The Author(s).