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Abstract Human organoids have been proposed to be powerful tools mimicking the physiopathological processes of the organs of origin. Recently, human pancreatic organoids (hPOs) have gained increasing attention due to potential theragnostic and regenerative medicine applications. However, the cellular components of hPOs have not been defined precisely. In this work, we finely characterized these structures, focusing first on morphology and identity-defining molecular features under long-term culture conditions. Next, we focused our attention on hPOs cell type composition using single-cell RNA sequencing founding a complex heterogeneity in ductal components, ranging from progenitor components to terminally differentiated ducts. Furthermore, an extensive comparison of human pancreatic organoids with previously reported transcriptomics signature of human and mouse pancreatic ductal populations, confirmed the functional pancreatic duct subpopulation heterogeneity. Finally, we showed that pancreatic organoid cells follow a precise developmental trajectory and utilize diverse signalling mechanisms, including EGF and SPP1, to facilitate cell-cell communication and maturation. Together our results offer an in-depth description of human pancreatic organoids providing a strong foundation for future in vitro diagnostic and translational studies of pancreatic health and disease.

Abstract Microgravity (µG) experienced during space flights promotes adaptation in several astronauts’ organs and tissues, with skeletal muscles being the most affected. In response to reduced gravitational loading, muscles (especially, lower limb and antigravity muscles) undergo progressive mass loss and alteration in metabolism, myofiber size, and composition. Skeletal muscle precursor cells (MPCs), also known as satellite cells, are responsible for the growth and maintenance of muscle mass in adult life as well as for muscle regeneration following damage and may have a major role in µG-induced muscle wasting. Despite the great relevance for astronaut health, very few data are available about the effects of real µG on human muscles. Based on the MyoGravity project, this study aimed to analyze: (i) the cellular and transcriptional alterations induced by real µG in human MPCs (huMPCs) and (ii) the response of human skeletal muscle to normal gravitational loading after prolonged exposure to µG. We evaluated the transcriptomic changes induced by µG on board the International Space Station (ISS) in differentiating huMPCs isolated from Vastus lateralis muscle biopsies of a pre-flight astronaut and an age- and sex-matched volunteer, in comparison with the same cells cultured on the ground in standard gravity (1×g) conditions. We found that huMPCs differentiated under real µG conditions showed: (i) upregulation of genes related to cell adhesion, plasma membrane components, and ion transport; (ii) strong downregulation of genes related to the muscle contraction machinery and sarcomere organization; and (iii) downregulation of muscle-specific microRNAs (myomiRs). Moreover, we had the unique opportunity to analyze huMPCs and skeletal muscle tissue of the same astronaut before and 30 h after a long-duration space flight on board the ISS. Prolonged exposure to real µG strongly affected the biology and functionality of the astronaut’s satellite cells, which showed a dramatic reduction of responsiveness to activating stimuli and proliferation rate, morphological changes, and almost inability to fuse into myotubes. RNA-Seq analysis of post- vs. pre-flight muscle tissue showed that genes involved in muscle structure and remodeling are promptly activated after landing following a long-duration space mission. Conversely, genes involved in the myelination process or synapse and neuromuscular junction organization appeared downregulated. Although we have investigated only one astronaut, these results point to a prompt readaptation of the skeletal muscle mechanical components to the normal gravitational loading, but the inability to rapidly recover the physiological muscle myelination/innervation pattern after landing from a long-duration space flight. Together with the persistent functional deficit observed in the astronaut’s satellite cells after prolonged exposure to real µG, these results lead us to hypothesize that a condition of inefficient regeneration is likely to occur in the muscles of post-flight astronauts following damage.

Plant-Derived Extracellular Vesicles extracellular vesicles (PDEVs) from organic agriculture (without the use of pesticides and microbicides) contain high levels of antioxidants. Organic PDEVs have shown an increased antioxidant power compared to PDEVs from single plants, suggesting a synergistic effect of the bioactives constitutively expressed in the PDEVs from single fruits. With this study, we wanted to investigate the beneficial effects of a mix of PDEVs on human skin cells. We found detectable levels of citric acid, ascorbic acid, glutathione, catalase, and SOD in a mix of PDEVs deriving from five different fruits (grape, red orange, papaya, pomegranate, and tangerine). We then treated H2O2-conditioned fibroblasts with the mix of PDEVs. The results showed that the PDEVs’ mixture reverted the H2O2-induced redox imbalance, restoring mitochondrial homeostasis, with a strong reduction of mitochondrial anion superoxide and an increase in sirtuin levels. The antioxidant action was consistent with wound repair on a lesion produced in a fibroblast’s monolayer. This result was consistent with an increased level of vimentin and matrix metalloproteinase-9, whose expression is directly related to the efficiency of the reparative processes. These data support a beneficial role of PDEVs in both preventing and treating skin injuries through their potent antioxidant and reparative activities.

Glioblastoma multiforme (GBM) is the most common primary brain tumor, characterized by a remarkable inner complexity and inter-tumor variability. Moreover, it is very aggressive and resistant to conventional treatments, so that it rapidly relapse. Therefore, there is an immediate need for experimental strategies to enhance our comprehension of GBM, aiming to mitigate its economic and social impact. Here, we described different in vivo and in vitro strategies currently used for the study of GBM. First, we gave a brief and general overview of the classical in vivo models, including xenograft mouse and zebrafish models and canine models, offering a wide range of advantages but also presenting a series of strong limitations. Thus, we described in vitro models, starting from more traditional 2D culture models, comparing different approaches and critically exposing the advantages and disadvantages of using one or the other methods. We also briefly described GBM 2D culture systems that allow recreating multiple cell-cell and cell-extracellular matrix contacts but still do not reflect the complexity of in vivo tumors. We finally described the intricacies of the more novel 3D in vitro models, e.g., spheroids and organoids. These sophisticated models have demonstrated exceptional suitability across a wide spectrum of applications in cancer research, ranging from fundamental scientific inquiries to applications in translational research. Their adaptability and three-dimensional architecture render them invaluable tools, offering new insights and paving the way for advancements in both basic and applied research.