A novel two-factor monosynaptic TRIO tracing method for assessment of circuit integration of hESC-derived dopamine transplants.

Patrick Aldrin-Kirk,Xiaohe Liu,Tiago Cardoso,Sara Nolbrant,Marcus Davidsson,Tomas Björklund,Andreas Heuer,Andrew F Adler,Malin Åkerblom,Malin Parmar

doi:10.1016/j.stemcr.2021.11.014

Patrick Aldrin-Kirk, Xiaohe Liu + Show 8 more

Open Access

https://doi.org/10.1016/j.stemcr.2021.11.014

Copy DOI

Abstract

SummaryTransplantation in Parkinson's disease using human embryonic stem cell (hESC)-derived dopaminergic (DA) neurons is a promising future treatment option. However, many of the mechanisms that govern their differentiation, maturation, and integration into the host circuitry remain elusive. Here, we engrafted hESCs differentiated toward a ventral midbrain DA phenotype into the midbrain of a preclinical rodent model of Parkinson's disease. We then injected a novel DA-neurotropic retrograde MNM008 adeno-associated virus vector capsid, into specific DA target regions to generate starter cells based on their axonal projections. Using monosynaptic rabies-based tracing, we demonstrated for the first time that grafted hESC-derived DA neurons receive distinctly different afferent inputs depending on their projections. The similarities to the host DA system suggest a previously unknown directed circuit integration. By evaluating the differential host-to-graft connectivity based on projection patterns, this novel approach offers a tool to answer outstanding questions regarding the integration of grafted hESC-derived DA neurons.

Highlights

Cell transplantation in Parkinson’s disease using human fetal ventral mesencephalon (VM) tissue has been pursued in the clinic over the last four decades (Barker et al, 2015)
Advances in recent years regarding the modulation of transplants (Aldrin-Kirk et al, 2016; Chen et al, 2016; Steinbeck et al, 2015) have again invigorated the field and enabled experimental studies of factors that govern a successful restoration of the basal ganglia circuitry (Bjorklund and Parmar, 2020)
In vitro differentiation of human embryonic stem cell (hESC) produce DA neurons of a ventral midbrain phenotype The differentiation protocol we used (Nolbrant et al, 2017) produces accurate VM progenitor patterning without any apparent influence of the lentiviral (LV)-derived Syn1-Cre expression (Figure S1)

Summary

Introduction

Cell transplantation in Parkinson’s disease using human fetal ventral mesencephalon (VM) tissue has been pursued in the clinic over the last four decades (Barker et al, 2015). Current hESC differentiation protocols aim to produce high-purity midbrain DA neurons (Grealish et al, 2014; Niclis et al, 2017; Nolbrant et al, 2017). While they are enriched in GIRK2 expressing DA neurons, the grafts contain DA neurons that innervate both A9 and A10 target regions (Grealish et al, 2014; Xiong et al, 2021). Homotopic graft placement (into the SN) holds the potential to provide complete circuit repair and form all the appropriate afferent connections of the intact nigrostriatal system

Objectives

Results

Discussion

Conclusion