Hypophosphatasia (HPP) is a genetic disease caused by one or several mutations in ALPL gene encoding the tissue-nonspecific alkaline phosphatase affecting the mineralization process. Due to its low prevalence and lack of recognition, this metabolic disorder is generally confused with other more frequent bone disorders. An assessment of serum total alkaline phosphatase (ALP) levels was performed in 78,590 subjects. Pyridoxal-5′-phosphate (PLP) concentrations were determined and ALPL gene was sequenced in patients potentially affected by HPP. Functional validation of the novel mutations found was performed using a cell-based assay. Our results showed persistently low serum ALP levels in 0.12% of subjects. Among the studied subjects, 40% presented with HPP-related symptoms. Nine of them (~28%) had a history of fractures, 5 (~16%) subjects showed chondrocalcinosis and 4 (~13%) subjects presented with dental abnormalities. Eleven subjects showed increased PLP concentrations. Seven of them showed ALPL gene mutations (2 of the mutations corresponded to novel genetic variants). In summary, we identified two novel ALPL gene mutations associated with adult HPP. Using this protocol, almost half of the studied patients were diagnosed with HPP. Based on these results, the estimated prevalence of mild HPP in Spain could be up to double than previously reported.

Familial Platelet Disorder with associated Myeloid Malignancy (FPDMM) is a rare platelet disorder caused by mutations in RUNX1. We generated an iPSC line (GENYOi005-A) from a FPDMM patient with a non-previously reported variant p.Thr196Ala. Non-integrative Sendai viruses expressing the Yamanaka reprogramming factors were used to reprogram peripheral blood mononuclear cells from this FPDMM patient. Characterization of GENYOi005-A included genetic analysis of RUNX1 locus, Short Tandem Repeats profiling, alkaline phosphatase enzymatic activity, expression of pluripotency-associated factors and differentiation studies in vitro and in vivo. This iPSC line will provide a powerful tool to study developmental alterations of FPDMM patients.

Platelets and their extracellular vesicles (EVs) have emerged as promising liquid biopsy biosources for cancer detection and monitoring. The megakaryoblastic MEG-01 cell line offers a controlled system for generating platelet-like particles (PLPs) and EVs through valproic-acid-induced differentiation. Here, we performed comprehensive characterization and proteomic validation of MEG-01-derived populations, native human platelets, and their EVs using nanoparticle tracking analysis, transmission electron microscopy, imaging flow cytometry and quantitative proteomics. MEG-01 megakaryocytic differentiation is characterized by polylobulated nuclei, proplatelet formation, and elevated CD41/CD42a expression. PLPs predominantly exhibit an activated-like phenotype (CD62P+, degranulated morphology), while microvesicles (100–500 nm) and exosomes (50–250 nm) displayed size distributions and phenotypic markers consistent with native platelet-derived EVs. Proteomics identified substantial core proteomes shared across fractions and fraction-specific patterns consistent with selective cargo partitioning during EV biogenesis. Functional enrichment indicated that MEG-01-derived vesicles preserve key hemostatic, cytoskeletal, and immune pathways commonly associated with platelet EV biology. Ingenuity Pathway Analysis showed that PLPs exhibit proliferative transcriptional programs (elevated MYC/RB1/TEAD1, reduced GATA1), while plasma exosomes display minimal differential pathway activation compared to MEG-01 exosomes. Overall, these findings suggest that MEG-01-derived EVs approximate certain aspects of megakaryocyte-lineage exosomes and activated platelet-like states, although they do not fully replicate native platelet biology. Notably, plasma exosomes show strong proteomic convergence with MEG-01 exosomes, whereas platelet exosomes retain distinct activation-related features.

In the tumor context, platelets play a significant role in primary tumor progression, dissemination and metastasis. Analysis of this interaction in various cancers, such as non-small cell lung cancer (NSCLC), demonstrate that platelets can both transfer and receive biomolecules (e.g. RNA and proteins) to and from the tumor at different stages, becoming tumor-educated platelets. To investigate how platelets are able to transfer oncogenic material, we developed in vitro platelet-like particles (PLPs), from a differentiated MEG-01 cell line, that stably carry RNA and protein of the KRAS^G12D oncogene in fusion with GFP. We co-cultured these PLPs with NSCLC H1975 tumor cells to assess their ability to transfer this material. We observed that the generated platelets were capable of stably expressing the oncogene and transferring both its RNA and protein forms to tumor cells using qPCR and imaging techniques. Additionally, we found that coculturing PLPs loaded with GFP-KRAS^G12D with tumor cells increased their proliferative capacity at specific PLP concentrations. In conclusion, our study successfully engineered an MEG-01 cell line to produce PLPs carrying oncogenic GFP-KRAS^G12D simulating the tumor microenvironment, demonstrating the efficient transfer of this oncogene to tumor cells and its significant impact on enhancing proliferation.