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Direct neural conversion of endogenous non-neuronal cells, such as resident glia, into therapeutic neurons has emerged as a promising strategy for brain repair, aiming to restore lost or damaged neurons. Proof-of-concept has been obtained from animal studies, yet these models do not efficiently recapitulate the complexity of the human brain, and further refinement is necessary before clinical translation becomes viable. One important aspect is the need to achieve efficient and precise targeting of human glial cells using non-integrating viral vectors that exhibit a high degree of cell type specificity. While various naturally occurring or engineered adeno-associated virus (AAV) serotypes have been utilized to transduce glia, efficient targeting of human glial cell types remains an unsolved challenge. In this study, we employ AAV capsid library engineering to find AAV capsids that selectively target human glia in vitro and in vivo. We have identified two families of AAV capsids that induce efficient targeting of human glia both in glial spheroids and after glial progenitor cell transplantation into the rat forebrain. Furthermore, we show the robustness of this targeting by transferring the capsid peptide from the parent AAV2 serotype onto the AAV9 serotype, which facilitates future scalability for the larger human brain.

Mosquito-borne diseases pose a significant threat in many Southeast Asian countries, particularly through the sylvatic cycle, which has a wildlife reservoir in forests and rural areas. Studying the composition and diversity of vectors and pathogen transmission is especially challenging in forests and rural areas due to their remoteness, limited accessibility, lack of power, and underdeveloped infrastructure. This study is based on the WHO mosquito sampling protocol, modifies technical details to support mosquito collection in difficult-to-access and resource-limited areas. Specifically, we describe the procedure for using rechargeable lithium batteries and solar panels to power the mosquito traps, demonstrate a workflow for processing and storing the mosquitoes in a -20 °C freezer, data management tools including microclimate data, and quality assurance processes to ensure the validity and reliability of the results. A pre- and post-test was utilized to measure participant knowledge levels. Additional research is needed to validate this protocol for monitoring vector-borne diseases in hard-to-reach areas within other countries and settings.

The extension of the highly successful Doppler technique into the near-infrared (0.9–2.5 μm) is highly desirable as it would open the possibility for searches for extra-solar planets around young stars, very low-mass stars and brown dwarfs. Here we review the current status of this technique and discuss future prospects with particular emphasis on challenging problems for the next decade.

This study describes the case of a health professional infected first by influenza virus A(H3N2) and then by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 11 days later. Respiratory samples and clinical data were collected from the patient and from close contacts. RNA was extracted from samples and reverse transcription–quantitative polymerase chain reaction (RT-qPCR) was used to investigate the viruses. The patient presented with two different illness events: the first was characterized by fever, chest and body pain, prostration and tiredness, which ceased on the ninth day; RT-qPCR was positive only for influenza virus A(H3N2). Eleven days after onset of the first symptoms, the patient presented with sore throat, nasal congestion, coryza, nasal itching, sneezing and coughing, and a second RT-qPCR test was positive only for SARS-CoV-2; in the second event, symptoms lasted for 11 days. SARS-CoV-2 sequencing identified the Omicron BA.1 lineage. Of the patient’s contacts, one was coinfected with influenza A(H3N2) and SARS-CoV-2 lineage BA.1.15 and the other two were infected only with SARS-CoV-2, one also with Omicron BA.1.15 and the other with BA.1.1. Our findings reinforce the importance of testing for different viruses in cases of suspected respiratory viral infection during routine epidemiological surveillance because common clinical manifestations of COVID-19 mimic those of other viruses, such as influenza.

Abstract Phlebotomine sand flies are proven or suspected vectors of several pathogens of importance, including leishmaniasis, bartonellosis and sand fly fevers. Although sand flies have a worldwide distribution, there has been limited research published on sand flies and sand fly-borne pathogens throughout the Greater Mekong Sub-region (GMS). This review followed the PRISMA guidelines to determine the biodiversity and presence of phlebotomine sand flies and their associated pathogens in the GMS, specifically Cambodia, Thailand, the Lao People’s Democratic Republic (Laos), Malaysia and Vietnam. A total of 1472 records were identified by searching electronic databases, scanning reference lists of articles and consulting experts in the field. After screening of title and abstracts, 178 records remained and were further screened for original data (n = 34), not having regional data (n = 14), duplication of data (n = 4), records not available (n = 4) and no language translation available (n = 2). A total of 120 studies were then included for full review, with 41 studies on sand fly-related disease in humans, 33 studies on sand fly-related disease in animals and 54 entomological studies focused on sand flies (5 papers contained data on > 1 category), with a majority of the overall data from Thailand. There were relatively few studies on each country, with the exception of Thailand, and the studies applied different methods to investigate sand flies and sand fly-borne diseases, impacting the ability to conduct meaningful meta-analysis. The findings suggest that leishmaniasis in humans and the presence of sand fly vectors have been reported across several GMS countries over the past 100 years, with local transmission in humans confirmed in Thailand and Vietnam. Additionally, local Mundinia species are likely transmitted by biting midges. Findings from this study provide a framework for future investigations to determine the geographic distribution and risk profiles of leishmaniasis and other associated sand fly-borne disease throughout the GMS. It is recommended that researchers expand surveillance efforts across the GMS, with an emphasis placed on entomological surveys, syndromic and asymptomatic monitoring in both humans and animals and molecular characterization of sand flies and sand fly-borne pathogens, particularly in the understudied countries of Cambodia, Vietnam and Laos. Graphical abstract

Tick-borne encephalitis virus (TBEV) causes neurological disease in humans, with varied clinical severity influenced by the viral subtype. TBEV is endemic to Mongolia, where both Siberian and Far-Eastern subtypes are present. Ixodes persulcatus is considered the main vector of TBEV in Mongolia; although, the virus has also been detected in Dermacentor species. To further characterize the disease ecology of TBEV within the endemic Selenge province of Mongolia, 1300 Ixodes persulcatus ticks were collected in May 2020 from regions outside Ulaanbaatar. Pooled tick samples (n = 20–50) were homogenized and the supernatant was inoculated into Vero cells. Two RT-PCR assays were conducted on the cell supernatant following an observed cytopathic effect: one for TBEV detection and the second for viral subtyping. Lysed cell cultures were processed for next-generation sequencing (NGS) using Illumina technology. TBEV was detected in 10.7% of tick pools (3/28), and isolates were identified as the Siberian subtype. Phylogenetic analysis showed PQ479142 clustering within the Siberian subtype and sharing high similarity with published isolates collected in Selenge in 2012 from Ixodes persulcatus. Subtype analysis of circulating TBEV isolates and sequencing analytics to track viral evolution in ticks are vital to continued understanding of the risk to local populations. [ABSTRACT FROM AUTHOR]

The extreme environments of ultra-short-period planets (USPs) make excellent laboratories to study how exoplanets obtain, lose, retain, and/or regain gaseous atmospheres. We present the confirmation and characterization of the USP TOI-1347 b, a 1.8 ± 0.1 R _⊕ planet on a 0.85 day orbit that was detected with photometry from the TESS mission. We measured radial velocities of the TOI-1347 system using Keck/HIRES and HARPS-N and found the USP to be unusually massive at 11.1 ± 1.2 M _⊕ . The measured mass and radius of TOI-1347 b imply an Earth-like bulk composition. A thin H/He envelope (>0.01% by mass) can be ruled out at high confidence. The system is between 1 and 1.8 Gyr old; therefore, intensive photoevaporation should have concluded. We detected a tentative phase-curve variation (3 σ ) and a secondary eclipse (2 σ ) in TESS photometry, which, if confirmed, could indicate the presence of a high-mean-molecular-weight atmosphere. We recommend additional optical and infrared observations to confirm the presence of an atmosphere and investigate its composition.

ABSTRACT Background: Brazil has one of the highest numbers of COVID-19 cases and deaths. Rio Grande do Sul (RS) in southern Brazil is one of the leading states in terms of case numbers. As part of the national public health network, the State Central Laboratory (LACEN-RS) changed its routine in 2020 to focus on the diagnosis of COVID-19. This study evaluated the laboratory surveillance of COVID-19 suspected cases analyzed at the LACEN-RS in 2020. Methods: Viral detection was performed using RT-qPCR in samples from patients with respiratory infection who met the study criteria. Viral RNA was isolated using commercial manual kits or automated extractors, and SARS-CoV-2 RT-qPCR was performed using the Bio-Manguinhos/Rio de Janeiro, IBMP/Paraná, or Allplex 2019-nCoV assay. In total, 360 representative SARS-CoV-2 samples were sequenced using the Illumina platform. Results: In total, 31,197 of 107,578 (positivity rate = 29%) tested positive for SARS-CoV-2. The number of RT-qPCR tests performed per month followed the COVID-19 epidemic curve observed for the state, with peaks in July-August and December. Females accounted for 63% of the samples, whereas the positivity rate was higher among males (33.1% males vs. 26.5% females). The positivity rate was higher in adults aged 50-79 years compared to the overall positivity rate. The majority of cases were observed in the capital, Porto Alegre, and the metropolitan region. Ten distinct lineages were identified, with B.1.1.28, B.1.1.33, and P.2 being the most frequent. Conclusions: Here, we describe laboratory surveillance of COVID-19 to identify priorities for epidemiological surveillance actions in RS.

Human pluripotent stem cells (hPSCs) are intrinsically able to self-organize into cerebral organoids that mimic features of developing human brain tissue. These three-dimensional structures provide a unique opportunity to generate cytoarchitecture and cell-cell interactions reminiscent of human brain complexity in a dish. However, current in vitro brain organoid methodologies often result in intra-organoid variability, limiting their use in recapitulating later developmental stages as well as in disease modeling and drug discovery. In addition, cell stress and hypoxia resulting from long-term culture lead to incomplete maturation and cell death within the inner core. Here, we used a recombinant silk microfiber network as a scaffold to drive hPSCs to self-arrange into engineered cerebral organoids. Silk scaffolding promoted neuroectoderm formation and reduced heterogeneity of cellular organization within individual organoids. Bulk and single cell transcriptomics confirmed that silk cerebral organoids display more homogeneous and functionally mature neuronal properties than organoids grown in the absence of silk scaffold. Furthermore, oxygen sensing analysis showed that silk scaffolds create more favorable growth and differentiation conditions by facilitating the delivery of oxygen and nutrients. The silk scaffolding strategy appears to reduce intra-organoid variability and enhances self-organization into functionally mature human brain organoids.

Dopaminergic (DA) neurons exhibit significant diversity characterized by differences in morphology, anatomical location, axonal projection pattern, and selective vulnerability to disease. More recently, scRNAseq has been used to map DA neuron diversity at the level of gene expression. These studies have revealed a higher than expected molecular diversity in both mouse and human DA neurons. However, whether different molecular expression profiles correlate with specific functions of different DA neurons or with their classical division into mesolimbic (A10) and nigrostriatal (A9) neurons, remains to be determined. To address this, we have developed an approach termed TARGET-seq (Tagging projections by AAV-mediated RetroGrade Enrichment of Transcriptomes) that links the transcriptional profile of the DA neurons with their innervation of specific target structures in the forebrain. Leveraging this technology, we identify molecularly distinct subclusters of human DA neurons with a clear link between transcriptome and axonal target-specificity, offering the possibility to infer neuroanatomical-based classification to molecular identity and target-specific connectivity. We subsequently used this dataset to identify candidate transcription factors along DA developmental trajectories that may control subtype identity, thus providing broad avenues that can be further explored in the design of next-generation A9 and A10 enriched DA-neurons for drug screening or A9 enriched DA cells for clinical stem cell-based therapies. [ABSTRACT FROM AUTHOR]

Arthropod-borne rickettsioses comprise a wide variety of subtypes that are endemic in Cambodia, but there remains very little data on the geographic distribution of the pathogens or their vectors. Surveys were conducted in Koh Kong and Preah Sihanouk Provinces between September 2017 and June 2018 to collect ectoparasites from peridomestic animals and the environment using dragging and flagging methods. Collected ectoparasites were sorted and identified morphologically, then pooled by species, host, and location for molecular detection using Rickettsia genus- and species-specific qPCR and/or multilocus sequence typing (MLST) assays. A total of 14,254 ectoparasites were collected including seven new locality records. Rickettsia species were detected in 35.5% (174/505) of the pools screened representing 3,149 randomly selected ectoparasites from the total collected. Rickettsia asembonensis was detected in 89.6% (147/164) of Rickettsia-positive flea pools and 3.6% (6/164) of the flea pools were positive for both R. asembonensis and Rickettsia felis. Candidatus Rickettsia senegalensis from Ctenocephalides orientis fleas and Rickettsia sp. close to Rickettsia japonica and Rickettsia heilongjiangensis from Haemaphysalis ticks were identified by MLST. This appears to be the first report of these new ectoparasite records and rickettsial species in southern Cambodia, suggesting a potential health risk to military and civilians in this region. Author summary: Rickettsiae are Gram-negative bacteria that cause acute undifferentiated febrile illness in humans. These pathogens are associated with arthropods and primarily transmitted by ectoparasites such as ticks, fleas, and mites. In Cambodia, rickettsial diseases have been documented in local patients, travelers and military personnel. However, the lack of entomological studies and awareness of these diseases hindered our comprehensive understanding of these pathogens and their arthropod vectors. Our manuscript provides a description of ectoparasite diversity and sheds light on their potential role in rickettsial disease transmission. Through molecular techniques, we uncover the prevalence and diversity of Rickettsia species in ectoparasites collected from various animal hosts in Koh Kong and Preah Sihanouk province. Rickettsia asembonensis, Rickettsia felis, and Candidatus Rickettsia senegalensis were all identified from Ctenocephalides orientis fleas, while Rickettsia species closely related to Rickettsia japonica, Rickettsia heilongjiangensis, and Rickettsia raoultii were found from Haemaphysalis ticks. Additionally, Rickettsia were also detected in Heterodoxus spiniger lice and Laelapidae mites, although we were unable to characterize the species. Insights into this pathogen-vector-host interface will better inform healthcare professionals, leading to more accurate diagnoses and increased awareness for better management of these diseases. [ABSTRACT FROM AUTHOR]

Tick-borne diseases are a major public health concern in Mongolia. Nomadic pastoralists, which make up ~ 26% of Mongolia’s population, are at an increased risk of both tick bite exposure and economic loss associated with clinical disease in herds. This study sought to further characterize tick-borne pathogens present in Dermacentor ticks (n = 1,773) sampled in 2019 from 15 of Mongolia’s 21 aimags (provinces). The ticks were morphologically identified and sorted into 377 pools which were then screened using Next-Generation Sequencing paired with confirmatory PCR and DNA sequence analysis. Rickettsia spp. were detected in 88.33% of pools, while Anaplasma spp. and Bartonella spp. were detected in 3.18 and 0.79% of pools, respectively. Khentii had the highest infection rate for Rickettsia spp. (76.61%; CI: 34.65–94.79%), while Arkhangai had the highest infection rate for Anaplasma spp. (7.79%; CI:4.04–13.72%). The exclusive detection of Anaplasma spp. in tick pools collected from livestock supports previous work in this area that suggests livestock play a significant role in disease maintenance. The detection of Anaplasma, Bartonella, and Rickettsia demonstrates a heightened risk for infection throughout Mongolia, with this study, to our knowledge, documenting the first detection of Bartonella melophagi in ticks collected in Mongolia. Further research deploying NGS methods is needed to characterize tick-borne pathogens in other endemic tick species found in Mongolia, including Hyalomma asiaticum and Ixodes persulcatus.

What happens to cells on engrafting into the brain in animal models to treat Parkinson’s disease is unclear. Here, the authors use scRNA-seq to examine ventral midbrain (VM)-patterned human embryonic stem cells after functional maturation in a pre-clinical rat model for Parkinson’s disease and identify perivascular-like cells.

O objetivo desta pesquisa é compreender os conceitos Migração e Diáspora a partir das experiências diaspóricas haitianas. Este enfoque torna possível traçar significações múltiplas que esses termos carregam e, enfim, situá-los no contexto das Américas – em especial, nas relações entre Brasil e Haiti – para suscitar reflexões sobre a atuação da Psicologia frente às questões que essas vivências impõem. Como encontrado a partir da revisão bibliográfica, o conceito de migração pode ser definido pela mobilidade de uma pessoa ou grupo por entre fronteiras estaduais e internacionais. É, porém, um erro reduzi-lo a isto, considerando todos os significados atribuídos às possibilidades migratórias e aos migrantes. O conceito de diáspora mostra-se ainda mais difícil de definir; inclui pertencer a uma comunidade, fora de sua origem, mas inscrita no entremeio de disputas culturais, políticas, tanto nas sociedades da imigração quanto de emigração. A partir das vivências haitianas no Brasil, mostra-se necessário compreender a complexidade desses termos, em especial em um contexto permeado de ideais colonialistas como o brasileiro. Por fim, é função da Psicologia produzir conhecimento que vá na contramão desses ideais e que considere as mobilidades e territórios como elementos na construção das subjetividades. É necessária uma implicação teórico-metodológica não patologizante, anticolonialista e antirracista, que enxergue as vivências migratórias em sua complexidade.

We present high-precision radial velocities (RVs) from the HARPS-N spectrograph for HD 79210 and HD 79211, two M0V members of a gravitationally bound binary system. We detect a planet candidate with a period of ${24.421}_{-0.017}^{+0.016}$ days around HD 79211 in these HARPS-N RVs, validating the planet candidate originally identified in CARMENES RV data alone. Using HARPS-N, CARMENES, and RVs spanning a total of 25 yr, we further refine the planet candidate parameters to P = 24.422 ± 0.014 days, K = 3.19 ± 0.27 m s ^−1 , M sin i = 10.6 ± 1.2 M _⊕ , and a = 0.142 ± 0.005 au. We do not find any additional planet candidate signals in the data of HD 79211, nor do we find any planet candidate signals in HD 79210. This system adds to the number of exoplanets detected in binaries with M-dwarf members and serves as a case study for planet formation in stellar binaries.

Radial velocity (RV) measurements of transiting multiplanet systems allow us to understand the densities and compositions of planets unlike those in the solar system. Kepler-102, which consists of five tightly packed transiting planets, is a particularly interesting system since it includes a super-Earth (Kepler-102d) and a sub-Neptune-sized planet (Kepler-102e) for which masses can be measured using RVs. Previous work found a high density for Kepler-102d, suggesting a composition similar to that of Mercury, while Kepler-102e was found to have a density typical of sub-Neptune size planets; however, Kepler-102 is an active star, which can interfere with RV mass measurements. To better measure the mass of these two planets, we obtained 111 new RVs using Keck/HIRES and Telescopio Nazionale Galileo/HARPS-N and modeled Kepler-102's activity using quasiperiodic Gaussian process regression. For Kepler-102d, we report a mass upper limit M _d < 5.3 M _⊕ (95% confidence), a best-fit mass M _d = 2.5 ± 1.4 M _⊕ , and a density ρ _d = 5.6 ± 3.2 g cm ^−3 , which is consistent with a rocky composition similar in density to the Earth. For Kepler-102e we report a mass M _e = 4.7 ± 1.7 M _⊕ and a density ρ _e = 1.8 ± 0.7 g cm ^−3 . These measurements suggest that Kepler-102e has a rocky core with a thick gaseous envelope comprising 2%–4% of the planet mass and 16%–50% of its radius. Our study is yet another demonstration that accounting for stellar activity in stars with clear rotation signals can yield more accurate planet masses, enabling a more realistic interpretation of planet interiors.

K2-136 is a late-K dwarf (0.742 ± 0.039 M _⊙ ) in the Hyades open cluster with three known, transiting planets and an age of 650 ± 70 Myr. Analyzing K2 photometry, we found that planets K2-136b, c, and d have periods of 8.0, 17.3, and 25.6 days and radii of 1.014 ± 0.050 R _⊕ , 3.00 ± 0.13 R _⊕ , and 1.565 ± 0.077 R _⊕ , respectively. We collected 93 radial velocity (RV) measurements with the High-Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph (Telescopio Nazionale Galileo) and 22 RVs with the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) spectrograph (Very Large Telescope). Analyzing HARPS-N and ESPRESSO data jointly, we found that K2-136c induced a semi-amplitude of 5.49 ± 0.53 m s ^−1 , corresponding to a mass of 18.1 ± 1.9 M _⊕ . We also placed 95% upper mass limits on K2-136b and d of 4.3 and 3.0 M _⊕ , respectively. Further, we analyzed Hubble Space Telescope and XMM-Newton observations to establish the planetary high-energy environment and investigate possible atmospheric loss. K2-136c is now the smallest planet to have a measured mass in an open cluster and one of the youngest planets ever with a mass measurement. K2-136c has ∼75% the radius of Neptune but is similar in mass, yielding a density of ${3.69}_{-0.56}^{+0.67}$ g cm ^−3 (∼2–3 times denser than Neptune). Mass estimates for K2-136b (and possibly d) may be feasible with more RV observations, and insights into all three planets’ atmospheres through transmission spectroscopy would be challenging but potentially fruitful. This research and future mass measurements of young planets are critical for investigating the compositions and characteristics of small exoplanets at very early stages of their lives and providing insights into how exoplanets evolve with time.

Since its detection in December of 2020, the SARS-CoV2 lineage P.1, descendent of B.1.1.28 lineage, has been identified in several places in Brazil and abroad. This Variant of Concern was considered highly prevalent in Northern Brazil and now is rapidly widening its geographical range. Here, we present epidemiological and genomic information of the first case of P1 lineage in Rio Grande do Sul state, in a patient with no reported travel history and a tracked transmission chain. These findings occurred in a tourist destination representing an important hub receiving tourists from diverse places.

Direct neural conversion of endogenous non-neuronal cells, such as resident glia, into therapeutic neurons has emerged as a promising strategy for brain repair, aiming to restore lost or damaged neurons. Proof-of-concept has been obtained from animal studies, yet these models do not efficiently recapitulate the complexity of the human brain, and further refinement is necessary before clinical translation becomes viable. One important aspect is the need to achieve efficient and precise targeting of human glial cells using non-integrating viral vectors that exhibit a high degree of cell type specificity. While various naturally occurring or engineered adeno-associated virus (AAV) serotypes have been utilized to transduce glia, efficient targeting of human glial cell types remains an unsolved challenge. In this study, we employ AAV capsid library engineering to find AAV capsids that selectively target human glia in vitro and in vivo. We have identified two families of AAV capsids that induce efficient targeting of human glia both in glial spheroids and after glial progenitor cell transplantation into the rat forebrain. Furthermore, we show the robustness of this targeting by transferring the capsid peptide from the parent AAV2 serotype onto the AAV9 serotype, which facilitates future scalability for the larger human brain. [ABSTRACT FROM AUTHOR]

Aims. We report the confirmation of a new transiting exoplanet orbiting the star TOI-5076. Methods. We present our vetting procedure and follow-up observations which led to the confirmation of the exoplanet TOI-5076b. In particular, we employed high-precision TESS photometry, high-angular-resolution imaging from several telescopes, and high-precision radial velocities from HARPS-N. Results. From the HARPS-N spectroscopy, we determined the spectroscopic parameters of the host star: Teff = (5070±143) K, log 푔 = (4.6±0.3), [Fe/H] = (+0.20±0.08), and [α/Fe] = 0.05±0.06. The transiting planet is a warm sub-Neptune with a mass mp = (16±2) M⊙, a radius rp =(3.2±0.l) R⊙ yielding a density ρp = (2.8±0.5) g cm−3. It revolves around its star approximately every 23.445 days. Conclusions. The host star is a metal-rich, K2V dwarf, located at about 82 pc from the Sun with a radius of R⋆ = (0.78±0.01) R⊙ and a mass of M⋆ = (0.80±0.07) M⊙. It forms a common proper motion pair with an M-dwarf companion star located at a projected separation of 2178 au. The chemical analysis of the host-star and the Galactic-space velocities indicate that TOI-5076 belongs to the old population of thin-to-thick-disk transition stars. The density of TOI-5076b suggests the presence of a large fraction by volume of volatiles overlying a massive core. We found that a circular orbit solution is marginally favored with respect to an eccentric orbit solution for TOI-5076b. [ABSTRACT FROM AUTHOR]

Human midbrain dopamine (DA) neurons are a heterogeneous group of cells that share a common neurotransmitter phenotype and are in close anatomical proximity but display different functions, sensitivity to degeneration, and axonal innervation targets. The A9 DA neuron subtype controls motor function and is primarily degenerated in Parkinson’s disease (PD), whereas A10 neurons are largely unaffected by the condition, and their dysfunction is associated with neuropsychiatric disorders. Currently, DA neurons can only be reliably classified on the basis of topographical features, including anatomical location in the midbrain and projection targets in the forebrain. No systematic molecular classification at the genome-wide level has been proposed to date. Although many years of scientific efforts in embryonic and adult mouse brain have positioned us to better understand the complexity of DA neuron biology, many biological phenomena specific to humans are not amenable to being reproduced in animal models. The establishment of human cell-based systems combined with advanced computational single-cell transcriptomics holds great promise for decoding the mechanisms underlying maturation and diversification of human DA neurons, and linking their molecular heterogeneity to functions in the midbrain. Human pluripotent stem cells have emerged as a useful tool to recapitulate key molecular features of mature DA neuron subtypes. Here, we review some of the most recent advances and discuss the current challenges in using stem cells, to model human DA biology. We also describe how single cell RNA sequencing may provide key insights into the molecular programs driving DA progenitor specification into mature DA neuron subtypes. Exploiting the state-of-the-art approaches will lead to a better understanding of stem cell-derived DA neurons and their use in disease modeling and regenerative medicine.

Dopaminergic (DA) neurons derived from human pluripotent stem cells (hPSCs) represent a renewable and available source of cells useful for understanding development, developing disease models, and stem-cell therapies for Parkinson’s disease (PD). To assess the utility of stem cell cultures as an in vitro model system of human DA neurogenesis, we performed high-throughput transcriptional profiling of ~20,000 ventral midbrain (VM)-patterned stem cells at different stages of maturation using droplet-based single-cell RNA sequencing (scRNAseq). Using this dataset, we defined the cellular composition of human VM cultures at different timepoints and found high purity DA progenitor formation at an early stage of differentiation. DA neurons sharing similar molecular identities to those found in authentic DA neurons derived from human fetal VM were the major cell type after two months in culture. We also developed a bioinformatic pipeline that provided a comprehensive long noncoding RNA landscape based on temporal and cell-type specificity, which may contribute to unraveling the intricate regulatory network of coding and noncoding genes in DA neuron differentiation. Our findings serve as a valuable resource to elucidate the molecular steps of development, maturation, and function of human DA neurons, and to identify novel candidate coding and noncoding genes driving specification of progenitors into functionally mature DA neurons.