Defining isoform diversity conserved in the brain and blood, related to the severity of Prader-Willi syndrome

Funding Summary

Dr. Godler has been investigating cell-specific changes in gene expression in blood and brain tissue samples from individuals with PWS, with the goal of developing blood-based biomarkers of PWS severity.  Here his collaborative will apply newer technologies to look at genes and proteins that are differentially expressed in PWS and use that knowledge to query databases to identify drugs that may be ‘repurposed’ to treat PWS. 

Lay Abstract

For people with PWS, their families, and the medical professionals caring for them, the pressing needs are identification of early clinical and/or biological predictors of symptoms including serious mental illness and constant hunger that may be targeted with specific treatments. The underlying biological mechanisms in key areas of the human brain, linked to these phenotypes, have also not been comprehensively studied. This project aims to define biological mechanisms in blood and brain underlying key symptoms of PWS to address these needs. It will bring together an interdisciplinary team of investigators with an outstanding record in the field, established state-of-the-art technologies, deep clinical expertise and access to the world’s largest collection of post-mortem brain tissues from individuals with PWS.
In our previous FPWR funded studies we identified 53 genes, responsible for functions of ribosomes or small components in each cell to be upregulated in different types of cells in brains of donors with PWS. There are many ribosomes in each cell with each involved in the process of making different proteins coded by the genes. Proteins are large, complex molecules that play many critical roles in the body. Each gene can produce many different proteins which depends on how this message is read by each cell. This protein specific message is known as an isoform. Of all the genes examined, we have found only one ribosomal gene called RPS18 (that contributes to important functions of the ribosome involved in protein production) to be upregulated in all types of cells in specific regions of the brain from donors with PWS. We then showed that this upregulation in blood was associated with severity of PWS in another group of living individuals, including intellectual functioning and behavioral problems. While these changes and related functions of the ribosome in making different isoforms have been previously implicated in autism, this is the first time they will be studied in the brain of donors and their levels related to severity of PWS.
In this project we will analyze this rich dataset from different regions of the brain with different functions to help us understand how abnormal activity of ribosomes influences expression of unique isoforms of proteins from the same genes in different types of cells. Our previous study findings suggest that we should focus on brain immune cells (glial cells) which support the proper functioning of neurons in the brain. Once we collect this valuable information, we plan to use it as part of a competitive renewal application in the second year of this project to determine how these changes are related to behavioral issues and other key clinical features seen in PWS. We will also use artificial intelligence to identify treatments from global drug databases, to target specific pathways, isoforms and proteins identified to be dysregulated in blood and brain tissues in different types of cells and relationships to severity in PWS. Together these will: (i) define genetic pathways dysregulated in PWS blood and brain cells of clinical significance, and (ii) identify existing medications used for other conditions.

Research Outcomes: Public Summary

This project analyzed tissues from different regions of the brain, called prefrontal cortex and cerebellum, that regulate appetite and different behaviors. These brain tissues were provided by the NIH NeuroBioBank from donors with Prader-Willi syndrome (PWS) caused by either deletion or uniparental disomy (UPD), as well as from donors of the same age and gender who were not affected by PWS. We used state-of-the-art technologies called multi-omics to generate one of the largest datasets collected to date for PWS research, on expression of genes in different types of cells such as brain immune cells (glial cells) which support the proper functioning of neurons in the brain. This dataset included over 460,000 transcripts which are messages of genes, with over 360,0000 isoforms in different types of cells, and over 8,000 proteins. Isoforms are variations of messages from genes to create different versions of proteins. These isoforms can be very different between different types of cells created by a process called alternative splicing, each with a slightly different function or role in the brain. PWS alternative splicing in different types of cells of the brain is not well understood and may be different between individuals with PWS caused by either deletion or UPD, as suggested by our pilot studies. This may explain differences in clinical features between these genetic types of PWS.
We were funded by FPWR in 2024 / 2025 and are now in process of analysing these data in detail: (i) to help us understand how abnormal activity of genes influences expression of isoforms and their protein products in individuals with PWS due to deletion and UPD; (ii) using artificial intelligence to identify treatments from global drug databases, to target specific pathways, isoforms and proteins identified to be dysregulated in different brain regions that regulate appetite and different behaviors affected in PWS. Together this work will: (i) define genetic pathways disrupted in PWS of clinical significance, and (ii) identify existing medications used for other conditions to target these pathways in future PWS clinical trials to address the needs of people with PWS, their families, and the clinicians caring for them. Upon completion our analyses and publications of the results we will share the extensive data with the broader research community to answer other questions of importance to people with PWS and their families.