Long non-coding RNA in pancreatic development and diabetes

• Applicant: Dr. Sandra Heller
• Subject Area: General Genetics and Functional Genome Biology ; Developmental Biology ; Cell Biology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 531689337

Diabetes is characterized by a large clinical and biological variability. While a small subset of juvenile onset diabetes is caused by single gene mutations (monogenic diabetes), frequent variants in these genes can also be associated with multifactorial diabetes. This overlap suggests that disease mechanisms and biological pathways are shared between different forms of diabetes. Our recent work added ONECUT1 as a diabetes gene with monogenic and multifactorial inheritance. Characterization of such genes responsible for monogenic diabetes are extremely valuable to discover important pathways involved in diabetes pathology. Over the past decade, advancing genomic analysis technologies have increased the discovery of functional long non-coding RNAs (lncRNA). However, there is little detailed knowledge about the influence of regulatory elements and their role in monogenic diabetes. Our genetic analysis identified a unique neonatal diabetes patient harboring a heterozygous ONECUT1 truncating variant but manifesting a phenotype similar to homozygous ONECUT1 mutations. Since no alteration in other MODY genes was detected, we hypothesize that a second mutation affecting proper regulation of the remaining ONECUT1 allele might exist in the non-coding genome. In line with our hypothesis that mutations in regulatory elements might impact pancreatic development and function, we already identified a lncRNA that could potentially represent the missing link in our heterozygous patient with neonatal diabetes. The overall aim of this project is to use a stem cell differentiation platform for functional and mechanistic characterization of this genomic region. First, we will delete this lncRNA in human embryonic stem cells and characterize the developmental stages towards pancreatic beta-cells in a subsequent in vitro differentiation in relation to our ONECUT1 KO model. Second, a detailed mechanistic characterization will shed light on the function of the described regulatory element in pancreatic endocrine development and diabetes pathophysiology. Third, we will unveil the detailed stage-specific role of our regulatory element that might be otherwise masked by developmental defects in previous stages. Overall, this project will describe to date unknown molecular pathomechanisms that are connected to alterations in regulatory sequences and help to better understand the components of the pancreatic transcriptional network, the basic principle to develop personalized diabetes therapy.

• DFG Programme: Research Grants