Generation of an induced pluripotent stem cell (iPSC) line from a patient with GEFS+ carrying a STX1B (p.Lys45delinsArgMetCysIleGlu and p.Leu46Met) mutation.

The STX1B gene encodes the presynaptic protein syntaxin-1B, which plays a major role in regulating fusion of synaptic vesicles. Mutations in STX1B are known to cause epilepsy syndromes, such as genetic epilepsies with febrile seizures plus (GEFS+). Here, we reprogrammed skin fibroblasts from a female patient affected by GEFS+ to human induced pluripotent stem cells (iPSCs). The patient carries an InDel mutation (c.133_134insGGATGTGCATTG; p.Lys45delinsArgMetCysIleGlu and c.135_136AC > GA; p.Leu46Met), located in the regulatory Habc-domain of STX1B. Successful reprogramming of cells was confirmed by a normal karyotype, expression of several pluripotency markers and the potential to differentiate into all three germ layers.

Diverse maturity-dependent and complementary anti-apoptotic brakes safeguard human iPSC-derived neurons from cell death.

In humans, most neurons are born during embryonic development and have to persist throughout the entire lifespan of an individual. Thus, human neurons have to develop elaborate survival strategies to protect against accidental cell death. We set out to decipher the developmental adaptations resulting in neuronal resilience. We demonstrate that, during the time course of maturation, human neurons install a complex and complementary anti-apoptotic signaling network. This includes i.) a downregulation of central proteins of the intrinsic apoptosis pathway including several caspases, ii.) a shift in the ratio of pro- and anti-apoptotic BCL-2 family proteins, and iii.) an elaborate regulatory network resulting in upregulation of the inhibitor of apoptosis protein (IAP) XIAP. Together, these adaptations strongly increase the threshold for apoptosis initiation when confronted with a wide range of cellular stressors. Our results highlight how human neurons are endowed with complex and redundant preemptive strategies to protect against stress and cell death.