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Gaucher Disease (GD), the most common lysosomal disorder, arises from mutations in the GBA1 gene and is characterized by a wide spectrum of phenotypes, ranging from mild hematological and visceral involvement to severe neurological disease. Neuronopathic patients display dramatic neuronal loss and increased neuroinflammation, whose molecular basis are still unclear. Using a combination of Drosophila dGBA1b loss-of-function models and GD patient-derived iPSCs differentiated towards neuronal precursors and mature neurons we showed that different GD- tissues and neuronal cells display an impairment of growth mechanisms with an increased cell death and reduced proliferation. These phenotypes are coupled with the downregulation of several Hippo transcriptional targets, mainly involved in cells and tissue growth, and YAP exclusion from nuclei. Interestingly, Hippo knock-down in the GBA-KO flies rescues the proliferative defect, suggesting that targeting the Hippo pathway can be a promising therapeutic approach to neuronopathic GD.A combination of Drosophila dGBA1b loss-of-function models and Gaucher Disease (GD) patient-derived iPSCs reveals an impairment in GD neuronal cell growth and that Hippo pathway hyperactivation contributes to the impairment.

Despite enormous improvements in pre-clinical and clinical research, acute leukemia still represents an open challenge for pediatric hematologists; both for a significant relapse rate and for long term therapy-related sequelae. In this context, the use of an innovative technology, such as induced pluripotent stem cells (iPSCs), allows to finely reproduce the primary features of the malignancy and can be exploited as a model to study the onset and development of leukemia in vitro. The aim of this review is to explore the recent literature describing iPSCs as a key tool to study different types of hematological malignancies, comprising acute myeloid leukemia, non-down syndrome acute megakaryoblastic leukemia, B cell acute lymphoblastic leukemia, and juvenile myelomonocytic leukemia. This model demonstrates a positive impact on pediatric hematological diseases, especially in those affecting infants whose onsets is found in fetal hematopoiesis. This evidence highlights the importance of achieving an in vitro representation of the human embryonic hematopoietic development and timing-specific modifications, either genetic or epigenetic. Moreover, further insights into clonal evolution studies shed light in the way of a new precision medicine era, where patient-oriented decisions and therapies could further improve the outcome of pediatric cases. Nonetheless, we will also discuss here the difficulties and limitations of this model.

Gaucher disease is a lysosomal storage disorder characterized by β-glucosidase enzyme deficiency and substrate accumulation, especially in cells of the reticuloendothelial system. Typical features of the disease are the unrestrained activation of inflammatory mechanisms, whose molecular pathways are still unclear. To investigate biological mechanisms underlying the macrophage activation in GD, we derived iPSCs from a healthy donor and a GD patient line and differentiated them into hematopoietic progenitors. While GD iPSCs are able to efficiently give rise to CD33+/CD45+ myeloid progenitors, the maturation towards the CD14+/CD163+ monocyte/macrophages fate resulted enhanced in the GD lines, that in addition displayed a decreased growth potential compared to control cells either in semisolid or in liquid culture. The GD lines growth impairment was associated with a significant upregulation of RIPK3 and MLKL, two key effectors of necroptosis, the inflammation related cell death pathway. The activation of necroptosis, which has already been linked to neuronopathic GD, may play a role in the disease proinflammatory condition and in the identified cell growth defects. Understanding the GD macrophage role in the alteration of mechanisms linked to cellular metabolism imbalance, cell death and inflammation are crucial in identifying new ways to approach the disease.

Gaucher disease (GD) is a monogenic disorder characterized byβ-glucocerebrosidase enzyme deficiency. Typical features of the diseaseare the unrestrained activation of inflammatory mechanisms andneuronal cell death in neuronopathic conditions, whose molecularpathways are still not fully understood. Recent evidences show thatupregulation of the Hippo pathway is associated with neuroinflamma-tion and neuronal cell death. We analyzed the Hippo pathway activitytaking advantage of a Drosophila Gaucher-like model characterized bydGBA1b knock-out (GBA1bKO).WefoundderegulationofCycE,dIAPandMYC, direct targets of the pathway both in Drosophila and mammals,which were severely reduced at transcript and protein level,suggestingacell growth impairment. Analyzing upstream components we foundthat Fat, an atypical cadherin upstream of the kinase complex, wasupregulated. Moreover the glypicans Dally and Dally-like, known to benegatively regulated by Fat and involved in glial and synapsedevelopment, were found downregulated in the GBA1bKObackground,supporting a role in neurological damage. On the other hand, theaberrant inflammatory condition of the hematological compartmentwas investigated in the human model of induced Pluripotent Stem Cells(iPSC), differentiated into hematopoietic progenitors. While GD iPSCswere able to differentiate into CD34+/CD43+/CD45+ progenitors, theyshowed a decreased proliferative potential compared to healthy donoriPSC either in semisolid and liquid culture, therefore exhibiting a growthimpairment. This effect was coupled with the activation of necroptosispathway with a significant upregulation of RIPK3 and MLKL both in thepluripotent and differentiated state. Correction of the mutation to rescuethe phenotype is ongoing, taking advantage of AAVS1 editing approachin order to develop a fully comparable cell model useful in a cell therapyperspective. These data obtained with suitable GD models support therole of Hippo and necroptosis effectors in GD, amenable of furtherconsideration as potential therapeutic targets.

La malattia di Gaucher è un disordine monogenico caratterizzato dal deficit dell’enzima β-glucocerebrosidasi. Dal momento che l’innesco aberrante di meccanismi infiammatori cellulari è un aspetto peculiare della malattia, ci siamo concentrati sullo studio del pathway della necroptosi, forma di morte cellulare programmata dettata dall’infiammazione. Dall’analisi dell’espressione genica e dalla valutazione dei livelli proteici in modelli cellulari Gaucher-like, ottenuti tramite inibizione enzimatica, abbiamo evidenziato come la chinasi RIP1, primo effettore della via di segnalazione sia iperattivato nello stato patologico. Per disporre di un sistema d’analisi più accurato stiamo mettendo a punto modelli che sfruttano cellule staminali pluripotenti indotte (iPSCs) derivate da paziente e donatore sano. Tramite gene editing la più comune mutazione puntiforme causante la malattia (N370S), è stata inserita in iPSCs derivate da donatore sano. Le cellule sono state trasfettate, tramite nucleofezione, con il plasmide pSpCas9(BB)-2A-Puro codificante per la Cas9 e per una guida a RNA in grado di indirizzarne il taglio sito-specifico. La sequenza stampo per l’inserimento della mutazione è stata introdotta sotto forma di DNA a singolo filamento. La presenza della mutazione è stata verificata tramite PCR effettuata con primer specifici su pool di cellule trasfettate. Parallelamente, da cellule mononucleate del sangue periferico di un paziente Gaucher con mutazione N370S/L444P sono state ottenute iPSCs grazie a trasduzione con i vettori virali Sendai codificanti per i fattori di riprogrammazione: Klf4, cMyc e KOS. Il monitoraggio del differenziamento verso destino ematopoietico sarà portato avanti concentrandosi nello specifico sul tipo cellulare macrofagico in quanto maggior target dell’accumulo sfingolipidico caratterizzante la malattia.