Determining the pathogenicity of genetic variants in pain-associated genes: Establishment of a refined protocol for patient-derived nociceptors and personalized application in chronic pain patients

• Applicant: Professorin Dr. Nurcan Üçeyler
• Subject Area: Molecular and Cellular Neurology and Neuropathology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 461440976

Screening for genetic alterations in pain-associated genes is increasingly performed in patients with pain syndromes of so far idiopathic origin and often results in findings that remain of unclear pathogenicity. Given their diagnostic, therapeutic, and prognostic uncertainty, these findings are a great challenge for treating physicians and patients. The only possibility to unravel if such variations are of clinical relevance is by investigating patient-derived nociceptors which may be generated via induced pluripotent stem cells (iPSC). This methodology, however, carries the limitation of almost uncontrollable cellular heterogeneity after neuron differentiation. This heterogeneity renders the application of cell-specific analysis impossible and also dramatically reduces the significance of the obtained data. In our translational project, we will meet these exact two challenges. By genetic screening of a comprehensively characterized patient cohort with chronic pain based on small fiber pathology, we will identify patients carrying genetic variants of so far unknown pathogenicity and will generate individual sensory neurons via iPSC. Combining specific staining techniques, differential FACS analysis, and electrophysiological characterization, we will isolate nociceptors that will allow personalized RNA sequencing which is currently hampered by cellular heterogeneity upon neuronal differentiation. Following a multidimensional approach and by integrative data analysis considering clinical phenotype and in vitro data, we will identify and characterize novel pathogenic variants in pain-associated genes and will provide treating physicians phenotypic features for clinical usage; further, we will formulate a refined protocol to specifically spot nociceptors among iPSC-derived sensory neurons in basic science. This translational project bears the immense potential to enrich and improve clinical and basic pain research by fresh perspectives and knowledge with sustainable impact on pain diagnostics, treatment, and prevention.

• DFG Programme: Research Grants