Besusso, D. | bioRxiv Science

bioRxiv2025

Cografting strategies uncover cell type dependent regulation of dopamine neuron specification and functional maturation in a pre clinical model of Parkinson`s Disease

Parkinsons disease (PD), the second most common neurodegenerative disorder, is characterized by the progressive loss of A9 dopaminergic neurons in the substantia nigra, leading to dopamine (DA) depletion in the striatum and subsequent motor symptoms. Transplantation of ventral midbrain-patterned DA (vmDA) progenitors derived from human pluripotent stem cells, aimed at restoring DA neurotransmission in the striatum, is being developed and currently explored in ongoing clinical trials. One factor that may improve the maturation and fate determination of DA neurons in vivo is the intercellular communication within the graft environment, ultimately affecting the therapeutic outcome. In this study, we co-transplanted vmDA progenitors with either glial, ventral forebrain or striatal progenitors into a preclinical xenograft PD model to investigate how these interactions shape the development, maturation, and function of therapeutic DA neurons. Our findings show that co-grafts with ventral forebrain progenitors increase the yield of DA neurons and also promote their functional maturation. Furthermore, we demonstrated that co-grafts with striatal neurons promote functional maturation and the acquisition of DA subtype identity. From these data, we identified EBF3 and PBX3 as candidate transcription factors directing DA neuron maturation and subtype specification, and then functionally validated their role in brain organoids. Taken together, our data highlight that the cellular microenvironment, including specific interactions with neighbouring cells, guides in vivo DA neuron specification and maturation. These findings provide a foundation for developing more refined and effective cell preparations for replacement therapy in PD, and define a conceptual framework that could inform stem cell-based strategies for other neurodegenerative diseases.

neuroscience↗

bioRxiv2021

Modeling autism-associated SHANK3 deficiency using human cortico-striatal organoids generated from single neural rosettes

Our understanding of the human brain is limited by the lack of experimental models to mechanistically probe the properties of brain cells at different developmental stages under normal and pathological conditions. We developed a new method for generating human cortico-striatal organoids from stem cell-derived single neural rosettes (SNRs) and used it to investigate cortico-striatal development and deficits caused by the deficiency of an autism- and intellectual disability-associated gene SHANK3. We show that SNR-derived organoids consist of different cortico-striatal cells, including pallial and subpallial progenitors, primary cortical and striatal neurons, interneurons, as well as macroglial and mural cells. We also demonstrate that neurons in SNR-derived organoids are predictably organized, functionally mature, and capable of establishing functional neural networks. Interestingly, we found that the cellular and electrophysiological deficits in SHANK3-deficient SNR-derived organoids are dependent on the level of SHANK3 expression and that organoids with complete hemizygous SHANK3 deletion have disrupted expression of several clustered protocadherins and multiple primate-specific zinc-finger genes. Together, this study describes a new method for using SNRs to generate organoids, provides new insights into the cell lineages associated with human cortico-striatal development, and identifies specific molecular pathways disrupted by hemizygous SHANK3 deletion, which is the most common genetic abnormality detected in patients with 22q13 deletion syndrome.

neuroscience↗