TREM2 MICROglia ENGENEering for treating dementiaS (TREM2MICROENGINES)

Project Information

TREM2MICROENGINES

Grant agreement ID: 101069395

DOI

10.3030/101069395

Project closed

EC signature date 18 April 2022

Start date 1 July 2022

End date 31 December 2023

Funded under

• European Research Council (ERC)

Total cost

No data

EU contribution

€ 150 000,00

Coordinated by

UNIVERSITA DEGLI STUDI DI PADOVA
Italy

Periodic Reporting for period 1 - TREM2MICROENGINES (TREM2 MICROglia ENGENEering for treating dementiaS (TREM2MICROENGINES))

Reporting period: 2022-07-01 to 2023-12-31

Summary of the context and overall objectives of the project

ERC PoC 2022 project TREM2μENGINES was intended at validating the efficacy of a novel treatment for Alzheimer’s Disease (AD) and Nasu-Hakola Disease (NHD) in murine models. A relevant proportion of AD cases and all forms of NHD are caused by pathogenic mutations in the Triggering receptor expressed on myeloid cells 2 (TREM2) gene, which lead to microglia dysfunction contributing to and/or causing the onset and manifestations of AD and NHD. The restoration of TREM2 function in microglia by intervening on key mechanisms contributing to neurodegeneration could thus have the potential to overcome the limited efficacy of current treatments for AD, which only exert symptomatic but not curative effects. TREM2µENGINES approach involves the brain-directed transplantation of hematopoietic stem/progenitor cells (HSCs) engineered by lentiviral vectors (LVs) to express robust levels of TREM2 in their central nervous system (CNS) myeloid/microglial progeny. In preliminary experiments, the engineered cells have shown the ability to reduce and prevent Aβ accumulation, mitigate neuroinflammation and restore physiological scavenging functions in the diseased CNS, benefiting AD in a robust animal model. The project was intended at further developing these initial evidences towards translational exploitation by comparing two different promoter sequences with different strength and regulation to drive TREM2 expression and by testing the approach also in a NHD model, namely Trem2 ko animals.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

- Activity 1, project design (Deliverable 1, completed): this activity was intended at the finalization of a detailed study plan describing the experimental activities and steps, the methods, the statistical considerations and data analysis modality that could allow testing in relevant animal models the working hypothesis of the project;
- Activity 2, availability of key resources and material verification (Deliverable 2, completed): this activity was intended at making available all the resources and materials needed to conduct the in vivo POC study;
- Activity 3, set up of the in vivo study (Deliverable 3, completed): this activity consisted in the generation of the study cohorts of the POC of efficacy study; in agreement with the original proposal, we generated two very large experimental cohorts by treating 5XFAD as well as Trem2 ko mice and their corresponding wild type controls. In addition to the planned experimental groups, for assessment of the different variables of interest for clinical development of our treatment approach, intravenous (IV) delivery of the genetically modified cells was also tested. At transplantation, the TI, RI and CI were characterized for cell count and viability, and their in vitro liquid culture progeny by evaluating vector content and clonogenic potential.
- Activity 4, in vivo POC experimental evaluation (Deliverable 4, completed for the 5XFAD cohort, partially completed for the Trem2 ko cohort); the in vivo study was intended to last for a total of 12 months post-transplant in 5XFAD mice and 6 months post-transplant in Trem2-/- KO animals and included the assessment of the feasibility and efficacy of the treatment.
- Activity 5, data analysis and interpretation (Deliverable 5, partially completed); Due to the enlargement of the experimental cohorts as compared to the original plan intended at increasing the informative potential of our study, we have recently completed the work on the 5XFAD model and are still processing some of the activities in the Trem2 ko model. Thus far, data analysis has revealed a superior performance (in the 5XFAD model) of the Reference Item as compared to the Test Item. Completion of the on-going analysis on the Trem2 ko cohorts will allow confirming this finding.
- Activity 6, report generation, patent submission and partnership search (Deliverable 5, partially completed): as stated above, completion of the on-going final testing on the Trem2 ko cohorts will allow us finalizing a report for further IP protection efforts. Meanwhile, we have intensively worked for the establishment of a partnership with ventures and Pharma, established multiple contacts with key stakeholders and are currently awaiting feedback from 2 potential partners. Importantly, based on the work here developed, we successfully applied for an EIC transition grant that is expected to begin on April 1st, 2024.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Our research in the context of TREM2µENGINES combined:
i) the IP-protected intra-cerebro-ventricular (ICV) route for HSC delivery;
ii) the expression of TREM2 and iii) the possible use of a newly developed IP-protected promoter for TREM2 restricted and regulated expression in transplant-derived microglia-like cells. The therapeutic potential of this treatment has been evaluated in a laboratory research setting using a relevant AD mouse model in preliminary testing, showing restoration of physiological microglia functions, prevention/reduction of amyloid beta accumulation and modulation of the CNS environment towards neuroprotection (Milazzo et al. under peer review). These early POC of efficacy data have now been confirmed and further expanded by comparing LVs encoding TREM2 under the control of a ubiquitous promoter vs the newly developed lineage-specific promoter, and the ICV with the intravenous delivery route potentially associated to a wider cell distribution within and outside the CNS, as well as by the use of a different and very relevant model, consisting in Trem2 ko animals. Furthermore, safety data were collected that would be essential to support the translational feasibility of this approach.