The challenges of administering cell-based therapies to patients with Parkinson’s disease

Nurr1 promotes neurogenesis of dopaminergic neuron and represses inflammatory factors in the transwell coculture system of neural stem cells and microglia

INTRODUCTION

Neural stem cells (NSCs) are the most promising cells for cell replacement therapy for Parkinson's disease (PD). However, a majority of the transplanted NSCs differentiated into glial cells, thereby limiting the clinical application. Previous studies indicated that chronic neuroinflammation plays a vital role in the degeneration of midbrain DA (mDA) neurons, which suggested the developing potential of therapies for PD by targeting the inflammatory processes. Thus, Nurr1 (nuclear receptor-related factor 1), a transcription factor, has been referred to play a pivotal role in both the differentiation of dopaminergic neurons in embryonic stages and the maintenance of the dopaminergic phenotype throughout life.

AIM

This study investigated the effect of Nurr1 on neuroinflammation and differentiation of NSCs cocultured with primary microglia in the transwell coculture system.

RESULTS

The results showed that Nurr1 exerted anti-inflammatory effects and promoted the differentiation of NSCs into dopaminergic neurons.

CONCLUSIONS

The results suggested that Nurr1 protects dopaminergic neurons from neuroinflammation insults by limiting the production of neurotoxic mediators by microglia and maintain the survival of transplanted NSCs. These phenomena provided a new theoretical and experimental foundation for the transplantation of Nurr1-overexpressed NSCs as a potential treatment of PD.

Cell Therapy for Parkinson's Disease: A Translational Approach to Assess the Role of Local and Systemic Immunosuppression

Neural transplantation is a promising therapeutic approach for neurodegenerative diseases; however, many patients receiving intracerebral fetal allografts exhibit signs of immunization to donor antigens that could compromise the graft. In this context, we intracerebrally transplanted mesencephalic pig xenografts into primates to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Parkinsonian primates received WT or CTLA4-Ig transgenic porcine xenografts and different durations of peripheral immunosuppression to test whether systemic plus graft-mediated local immunosuppression might avoid rejection. A striking recovery of spontaneous locomotion was observed in primates receiving systemic plus local immunosuppression for 6 mo. Recovery was associated with restoration of dopaminergic activity detected both by positron emission tomography imaging and histological examination. Local infiltration by T cells and CD80/86+ microglial cells expressing indoleamine 2,3-dioxigenase were observed only in CTLA4-Ig recipients. Results suggest that in this primate neurotransplantation model, peripheral immunosuppression is indispensable to achieve the long-term survival of porcine neuronal xenografts that is required to study the beneficial immunomodulatory effect of local blockade of T cell costimulation.