In Parkinson's disease (PD), substantia nigra (SN) dopaminergic (DA) neurons degenerate, while related ventral tegmental area (VTA) DA neurons remain relatively unaffected. Here, we present a methodology that directs the differentiation of mouse and human pluripotent stem cells toward either SN-or VTA-like DA lineage and models their distinct vulnerabilities. We show that the level of WNT activity is critical for the induction of the SN-and VTA-lineage transcription factors Sox6 and Otx2, respectively. Both WNT signaling modulation and forced expression of these transcription factors can drive DA neurons toward the SN-or VTA-like fate. Importantly, the SN-like lineage enriched DA cultures recapitulate the selective sensitivity to mitochondrial toxins as observed in PD, while VTA-like neuron-enriched cultures are more resistant. Furthermore, a proteomics approach led to the identification of compounds that alter SN neuronal survival, demonstrating the utility of our strategy for disease modeling and drug discovery.

Midbrain dopaminergic (DA) axons make long longitudinal projections towards the striatum. Despite the importance of DA striatal innervation, processes involved in establishment of DA axonal connectivity remain largely unknown. Here we demonstrate a striatal-specific requirement of transcriptional regulator Nolz1 in establishing DA circuitry formation. DA projections are misguided and fail to innervate the striatum in both constitutive and striatal-specific Nolz1 mutant embryos. The lack of striatal Nolz1 expression results in nigral to pallidal lineage conversion of striatal projection neuron subtypes. This lineage switch alters the composition of secreted factors influencing DA axonal tract formation and renders the striatum non-permissive for dopaminergic and other forebrain tracts. Furthermore, transcriptomic analysis of wild-type and Nolz1−/− mutant striatal tissue led to the identification of several secreted factors that underlie the observed guidance defects and proteins that promote DA axonal outgrowth. Together, our data demonstrate the involvement of the striatum in orchestrating dopaminergic circuitry formation.

Introduction The Endosialin/CD248/TEM1 protein is expressed in adipose tissue and its expression increases with obesity. Recently, genetic deletion of CD248 has been shown to protect mice against atherosclerosis on a high fat diet. Objectives We investigated the effect of high fat diet feeding on visceral fat pads and circulating lipid profiles in CD248 knockout mice compared to controls. Methods From 10 weeks old, CD248−/− and +/+ mice were fed either chow (normal) diet or a high fat diet for 13 weeks. After 13 weeks the metabolic profiles and relative quantities of circulating lipid species were assessed using ultra high performance liquid chromatography-quadrupole time-of flight mass spectrometry (UHPLC–MS) with high resolution accurate mass (HRAM) capability. Results We demonstrate a specific reduction in the size of the perirenal fat pad in CD248−/− mice compared to CD248+/+, despite similar food intake. More strikingly, we identify significant, diet-dependent differences in the serum metabolic phenotypes of CD248 null compared to age and sex-matched wildtype control mice. Generalised protection from HFD-induced lipid accumulation was observed in CD248 null mice compared to wildtype, with particular reduction noted in the lysophosphatidylcholines, phosphatidylcholines, cholesterol and carnitine. Conclusions Overall these results show a clear and protective metabolic consequence of CD248 deletion in mice, implicating CD248 in lipid metabolism or trafficking and opening new avenues for further investigation using anti-CD248 targeting agents.