PhD Scientific Days 2025

Theoretical and Translational Medicine II.

Developing cell-based bioassays for clinical trials - the use of patient-derived induced neurons to stud autophagy in the Fell-HD trial

Name of the presenter

Vörös Kinga

Institute/workplace of the presenter

Institute of Translational Medicine, HCEMM-SU-Neurobiology and Neurodegenerative Diseases Research Group

Authors

Kinga Vörös¹, Dimitris Apostolopoulos², Souha Klibi³, Ágnes Varga⁴, Roland Zsoldos⁴, Győző Szenci⁵, Anna A. Abbas⁴, Balázs Kis⁴, Bendegúz Sramkó⁴, Lea Danics⁴, Shaline Fazal², Szabolcs Takáts⁵, Csaba Kerepesi³, Roger A. Barker², Karolina Pircs⁴

1: Institute of Translational Medicine, HCEMM-SU-Neurobiology and Neurodegenerative Diseases Research Group
2: University of Cambridge, Cambridge, UK
3: HUN-REN-SZTAKI-SU Rejuvenation Research Group, Budapest, Hungary
4: HCEMM-SU-Neurobiology and Neurodegenerative Diseases Research Group, Budapest, Hungary
5: Department of Anatomy, Cell- and Developmental Biology, Eötvös Loránd University, Budapest, Hungary

Text of the abstract

Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by CAG expansions in the huntingtin gene (HTT). These expansions produce mutated huntingtin protein (mHtt). HD is incurable and typically presents in
mid-life. It progresses to death over a 20-year period. Autophagy, a lysosomal degradation pathway that ensures cytoplasmic homeostasis, is dysfunctional in HD, thus contributing to mHTT protein accumulation.
Preclinically, it has been shown that felodipine can upregulate autophagy and clear protein aggregates in cells, including neural cells in HD. Thus a phase II clinical trial was undertaken (Fell-HD) to assess the tolerability and feasibility of testing this drug in patients with early-stage HD while also looking for any signal of efficacy.
Given we cannot look at autophagy in the living human brain, we sought to do this using induced neurons (iN) directly reprogrammed from skin fibroblasts from the FELL-HD participants. Transdifferentiated iNs keep the genetic and aging signatures
of the donor bypassing any stem cell or neuroprogenitor phase during conversion. We converted 7 control and 18 Fell-HD patient-derived fibroblasts to iNs with the same conversion efficiency and purity. DNA methylation array and analysis in iNs showed
accelerated aging in some patients. Moreover, most HD-iNs showed a less elaborate neuronal morphology and increased HTT expression using qPCR. We used 0.1 μM and 1 μM felodipine treatment for 24h to assess its effects. After 28 days of conversion, followed by Felodipine treatment iNs were fixed and counterstained using neuronal and autophagy markers to determine neuronal morphology and subcellular autophagy changes using high-content automated screening microscopy. Additionally, HTT measurements were again performed using qPCR after treatment. Our results showed that Felodipine enhanced autophagy in only a subset of patients while having no obvious adverse effects on HD-iNs. Lastly, we compared and correlated our preclinical results with FELL-HD trial outcomes - the patient’s cognitive and motor scores - and found some correlation to clinical response.
In summary, this project, using an in vitro preclinical iN model, offers a new approach to studying pathways targeted by drugs that cannot be studied in the living human brain and opens up a new dimension in testing agents in the clinic.