From 2D to 3D: Development of Monolayer Dopaminergic Neuronal and Midbrain Organoid Cultures for Parkinson's Disease Modeling and Regenerative Therapy.

Parkinson's Disease (PD) is a prevalent neurodegenerative disorder that is characterized pathologically by the loss of A9-specific dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) of the midbrain. Despite intensive research, the etiology of PD is currently unresolved, and the disease remains incurable. This, in part, is due to the lack of an experimental disease model that could faithfully recapitulate the features of human PD. However, the recent advent of induced pluripotent stem cell (iPSC) technology has allowed PD models to be created from patient-derived cells. Indeed, DA neurons from PD patients are now routinely established in many laboratories as monolayers as well as 3D organoid cultures that serve as useful toolboxes for understanding the mechanism underlying PD and also for drug discovery. At the same time, the iPSC technology also provides unprecedented opportunity for autologous cell-based therapy for the PD patient to be performed using the patient's own cells as starting materials. In this review, we provide an update on the molecular processes underpinning the development and differentiation of human pluripotent stem cells (PSCs) into midbrain DA neurons in both 2D and 3D cultures, as well as the latest advancements in using these cells for drug discovery and regenerative medicine. For the novice entering the field, the cornucopia of differentiation protocols reported for the generation of midbrain DA neurons may seem daunting. Here, we have distilled the essence of the different approaches and summarized the main factors driving DA neuronal differentiation, with the view to provide a useful guide to newcomers who are interested in developing iPSC-based models of PD.

Ovarian morphology is a marker of heritable biochemical traits in sisters with polycystic ovaries.

CONTEXT: Polycystic ovary syndrome (PCOS) is a common endocrinopathy of uncertain etiology but with strong evidence for a genetic contribution. OBJECTIVE: The objective of the study was to test the hypothesis that the typical polycystic ovarian morphology is a marker of inherited biochemical features in families of women with PCOS. DESIGN: A study of probands with PCOS and their sisters. PATIENTS: Patients included 125 probands and 214 sisters. All probands had PCOS, defined by symptoms of anovulation and/or hyperandrogenism with polycystic ovaries on ultrasound. Affected sisters were defined by polycystic ovaries, regardless of symptoms, and unaffected sisters defined by normal ovarian morphology. SETTING: This was a clinic-based study. MAIN OUTCOME MEASURES: Clinical, endocrine, and metabolic features in the various groups were compared, and estimates of broad-sense heritability were obtained using the quantitative transmission disequilibrium test. RESULTS: Although affected sisters had fewer symptoms than probands (30% had no symptoms of PCOS), serum testosterone, androstenedione, LH, and fasting insulin and insulin sensitivity were similar in the two groups with polycystic ovaries but significantly different from those in unaffected sisters or controls. We observed moderate to high heritabilities for all traits studied in affected sister pairs, whereas heritabilities calculated from discordant siblings were substantially lower. CONCLUSIONS: These data provide further evidence for a genetic basis of PCOS. The high heritability of biochemical features in probands and affected sisters, despite wide variation in symptoms, shows that not only are these biochemical traits strongly influenced by genetic factors but also, importantly, that polycystic ovarian morphology is an index of inherited traits in families with PCOS.

Analysis of multiple data sets reveals no association between the insulin gene variable number tandem repeat element and polycystic ovary syndrome or related traits.

CONTEXT: Variation at the insulin gene VNTR (variable number tandem repeat) minisatellite has been reported to be associated with polycystic ovary syndrome (PCOS), but findings have been inconsistent and all studies have featured small sample sizes. OBJECTIVE: To gain a robust understanding of the role of the INS-VNTR in PCOS susceptibility. DESIGN: Case-control, family-based association and quantitative trait analyses. SETTING AND PARTICIPANTS: A UK population comprising 255 parent-offspring trios, 185 additional cases, and 1062 control subjects (cases and controls all British/Irish) as well as 1599 women from a northern Finland population-based birth cohort characterized for PCO symptomatology and testosterone levels. VNTR class was inferred from genotyping of the -23HphI variant. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): INS-VNTR genotype frequencies between subject groups, body mass index, and testosterone levels by genotype. RESULTS: Case-control analyses in both UK and Finnish samples failed to confirm previously reported class III allele associations with PCOS (UK, P = 0.43, Finnish, P = 0.31; Kruskal-Wallis chi2). Transmission analysis in trios showed no excess transmission of either allele (P = 0.62), regardless of parent of origin (maternal: P = 0.73; paternal: P = 0.66). No association between genotype and testosterone levels was seen in any sample (UK PCOS subjects, P = 0.95; Finnish symptomatic cases, P = 0.38; Finnish control women, P = 0.58). CONCLUSIONS: Despite the strong biological candidacy and supportive data from previous studies, we conclude that variation at the INS-VNTR has no major role in the development of PCOS.

Large-scale analysis of the relationship between CYP11A promoter variation, polycystic ovarian syndrome, and serum testosterone.

CYP11A, the gene encoding p450scc, a key enzyme in steroid biosynthesis, is a strong biological candidate for polycystic ovary syndrome (PCOS) susceptibility. Four of the five published studies that have examined CYP11A for evidence of linkage and/or association have reported significant relationships with polycystic ovary (PCO) status and/or serum testosterone levels. However, study sizes have been modest, and the current study aimed to reevaluate these findings using significantly larger clinical resources. A pair of CYP11A promoter microsatellites, including the pentanucleotide (D15S520) previously implicated in trait susceptibility, were genotyped in 371 PCOS patients of United Kingdom origin, using both case-control and family-based association methods, and in 1589 women from a population-based birth cohort from Finland characterized for PCO symptomatology and testosterone levels. Although nominally significant differences in allele and genotype frequencies at both loci were observed in the United Kingdom case-control study (for example, an excess of the pentanucleotide four-repeat allele in cases, P = 0.005), these findings were not substantiated in the other analyses, and no discernable relationship was seen between variation at these loci and serum testosterone levels. These studies indicate that the strength of, and indeed the existence of, associations between CYP11A promoter variation and androgen-related phenotypes has been substantially overestimated in previous studies.