Regulatory T (TREG) cells develop via a program orchestrated by the transcription factor forkhead box protein P3 (FOXP3). Maintenance of the TREG cell lineage relies on sustained FOXP3 transcription via a mechanism involving demethylation of cytosine-phosphate-guanine (CpG)-rich elements at conserved non-coding sequences (CNS) in the FOXP3 locus. This cytosine demethylation is catalyzed by the ten–eleven translocation (TET) family of dioxygenases, and it involves a redox reaction that uses iron (Fe) as an essential cofactor. Here, we establish that human and mouse TREG cells express Fe-regulatory genes, including that encoding ferritin heavy chain (FTH), at relatively high levels compared to conventional T helper cells. We show that FTH expression in TREG cells is essential for immune homeostasis. Mechanistically, FTH supports TET-catalyzed demethylation of CpG-rich sequences CNS1 and 2 in the FOXP3 locus, thereby promoting FOXP3 transcription and TREG cell stability. This process, which is essential for TREG lineage stability and function, limits the severity of autoimmune neuroinflammation and infectious diseases, and favors tumor progression. These findings suggest that the regulation of intracellular iron by FTH is a stable property of TREG cells that supports immune homeostasis and limits the pathological outcomes of immune-mediated inflammation.

NFIX, a member of the nuclear factor I (NFI) family of transcription factors, is known to be involved in muscle and central nervous system embryonic development. However, its expression in adults is limited. Similar to other developmental transcription factors, NFIX has been found to be altered in tumors, often promoting pro-tumorigenic functions, such as leading to proliferation, differentiation, and migration. However, some studies suggest that NFIX can also have a tumor suppressor role, indicating a complex and cancer-type dependent role of NFIX. This complexity may be linked to the multiple processes at play in regulating NFIX, which include transcriptional, post-transcriptional, and post-translational processes. Moreover, other features of NFIX, including its ability to interact with different NFI members to form homodimers or heterodimers, therefore allowing the transcription of different target genes, and its ability to sense oxidative stress, can also modulate its function. In this review, we examine different aspects of NFIX regulation, first in development and then in cancer, highlighting the important role of NFIX in oxidative stress and cell fate regulation in tumors. Moreover, we propose different mechanisms through which oxidative stress regulates NFIX transcription and function, underlining NFIX as a key factor for tumorigenesis.

LAMA2, coding for the laminin-α2 chain, is a crucial ECM component, particularly abundant in skeletal muscle. Mutations inLAMA2trigger the often-lethalLAMA2-congenital muscular dystrophy (LAMA2-CMD). Various phenotypes have been linked to LAMA2-CMD; nevertheless, the precise mechanisms that malfunction during disease onset in utero remain unknown. We generatedLama2-deficient C2C12 cells and found thatLama2-deficient myoblasts display proliferation, differentiation, and fusion defects, DNA damage, oxidative stress, and mitochondrial dysfunction. Moreover, fetal myoblasts isolated from thedy^Wmouse model of LAMA2-CMD display impaired differentiation and fusion in vitro. We also showed that disease onset during fetal development is characterized by a significant down-regulation of gene expression in muscle fibers, causing pronounced effects on cytoskeletal organization, muscle differentiation, and altered DNA repair and oxidative stress responses. Together, our findings provide unique insights into the critical importance of the laminin-α2 chain for muscle differentiation and muscle cell homeostasis.

Despite advances in the treatment of cutaneous melanoma, there is still a high percentage of patients who fail to respond or develop resistance to treatment. Establishing robust in vitro melanoma models will enable mechanism-based drug screening while reducing animal testing. In this work, a three-dimensional (3D) melanoma skin model (3DMSM) was developed on a porous scaffold. The culture of three melanoma cell lines (SKMEL-1, A375, and G361) in co-culture with human fibroblasts, melanocytes, and keratinocytes allowed the formation of the dermis, and stratified epidermis. Tumors were established in this model using two methodologies: adding previously formed melanoma cell aggregates (CA) or seeding melanoma cells directly into the dermis (CD). In this model, melanoma cells remain in their original microenvironment and, after proliferation, invade the basal layer. The model recapitulates correct melanocyte localization, epidermal disruption, extracellular matrix (ECM) remodeling, including collagen deposition, and epithelial-to-mesenchymal transition (EMT). Additionally, the cytokine profiles studied indicate that the model could mirror the inflammatory and immune-evasive traits of melanoma. Overall, 3DMSM provides a useful tool for understanding the mechanisms of melanoma progression and invasion, and for developing personalized medicine strategies through the implementation of a patient-derived model.