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Freson, K.

Publications and source records attributed to Freson, K..

2 recordsLinked to original sources

Turbulence orchestrates actin-mitochondria dynamics to preserve GPIbα and support iPSC-derived platelet biogenesis

The in vitro manufacturing of induced pluripotent stem cell-derived platelets (iPSC-platelets) remains limited by low yield and poor quality, thus impeding practical clinical application. To address this, we developed a turbulence-assisted system using defined physical stimulation to enhance platelet production from immortalized megakaryocyte progenitor cell lines (imMKCLs). This approach significantly increases the yield of glycoprotein Ib (GPIb) functional iPSC-platelets. However, the underlying mechanisms remained unclear. Here, we reveal that GPIb iPSC-platelets retain high mitochondrial membrane potential, low phosphatidylserine (PS) exposure, and active ATP-dependent flippases, preserving mitochondrial integrity and platelet functionality. In contrast, GPIb- platelets exhibit PS exposure, ADAM17 activation, and selective GPIb shedding. Notably, turbulent flow induces late-stage actin depolymerization, promoting even mitochondrial distribution within maturing imMKCLs and enhancing mitochondrial inheritance to iPSC-platelets. These findings highlight the key role of turbulence in regulating actin dynamics and mitochondrial allocation during platelet biogenesis, providing a mechanistic foundation for improving in vitro platelet production for therapeutic use.

cell biology↗

Diagnostic high-throughput sequencing of 2,390 patients with bleeding, thrombotic and platelet disorders

A targeted high-throughput sequencing (HTS) panel test for clinical diagnostics requires careful consideration of the inclusion of appropriate diagnostic-grade genes, the ability to detect multiple types of genomic variation with high levels of analytic sensitivity and reproducibility, and variant interpretation by a multi-disciplinary team (MDT) in the context of the clinical phenotype. We have sequenced 2,390 index patients using the ThromboGenomics HTS panel test of diagnostic-grade genes known to harbour variants associated with rare bleeding, thrombotic or platelet disorders (BPD). The diagnostic rate was determined by the clinical phenotype, with an overall rate of 50.4% for all thrombotic, coagulation, platelet count and function disorder patients and a rate of 6.2% for patients with unexplained bleeding disorders characterized by normal hemostasis test results. The MDT classified 756 unique variants, including copy number and intronic variants, as Pathogenic, Likely Pathogenic or Variants of Uncertain Significance. Almost half (49.7%) of these variants are novel and 41 unique variants were identified in 7 genes recently found to be implicated in BPD. Inspection of canonical hemostasis pathways identified 29 patients with evidence of oligogenic inheritance. A molecular diagnosis has been reported for 897 index patients providing evidence that introducing a HTS genetic test for BPD patients is meeting an important unmet clinical need.\n\nKey pointsO_LIHigh-throughput sequencing (HTS) test reveals a molecular diagnosis for 38% of 2,390 patients with bleeding, thrombotic and platelet disorders.\nC_LIO_LIThromboGenomics HTS test validates recent gene discoveries and detects copy number and intronic variants.\nC_LI

genetics↗