Generation of hypothalamic arcuate organoids from human induced pluripotent stem cells.

Human brain organoids represent remarkable platforms for recapitulating features of human brain development and diseases. Existing organoid models do not resolve fine brain subregions, such as different nuclei in the hypothalamus. We report the generation of arcuate organoids (ARCOs) from human induced pluripotent stem cells (iPSCs) to model the development of the human hypothalamic arcuate nucleus. Single-cell RNA sequencing of ARCOs revealed significant molecular heterogeneity underlying different arcuate cell types, and machine learning-aided analysis based on the neonatal human hypothalamus single-nucleus transcriptome further showed a human arcuate nucleus molecular signature. We also explored ARCOs generated from Prader-Willi syndrome (PWS) patient iPSCs. These organoids exhibit aberrant differentiation and transcriptomic dysregulation similar to postnatal hypothalamus of PWS patients, indicative of cellular differentiation deficits and exacerbated inflammatory responses. Thus, patient iPSC-derived ARCOs represent a promising experimental model for investigating nucleus-specific features and disease-relevant mechanisms during early human arcuate development.

Decoding neuronal composition and ontogeny of individual hypothalamic nuclei.

The hypothalamus plays crucial roles in regulating endocrine, autonomic, and behavioral functions via its diverse nuclei and neuronal subtypes. The developmental mechanisms underlying ontogenetic establishment of different hypothalamic nuclei and generation of neuronal diversity remain largely unknown. Here, we show that combinatorial T-box 3 (TBX3), orthopedia homeobox (OTP), and distal-less homeobox (DLX) expression delineates all arcuate nucleus (Arc) neurons and defines four distinct subpopulations, whereas combinatorial NKX2.1/SF1 and OTP/DLX expression identifies ventromedial hypothalamus (VMH) and tuberal nucleus (TuN) neuronal subpopulations, respectively. Developmental analysis indicates that all four Arc subpopulations are mosaically and simultaneously generated from embryonic Arc progenitors, whereas glutamatergic VMH neurons and GABAergic TuN neurons are sequentially generated from common embryonic VMH progenitors. Moreover, clonal lineage-tracing analysis reveals that diverse lineages from multipotent radial glia progenitors orchestrate Arc and VMH-TuN establishment. Together, our study reveals cellular mechanisms underlying generation and organization of diverse neuronal subtypes and ontogenetic establishment of individual nuclei in the mammalian hypothalamus.

In vivo clonal analysis reveals spatiotemporal regulation of thalamic nucleogenesis.

The thalamus, a crucial regulator of cortical functions, is composed of many nuclei arranged in a spatially complex pattern. Thalamic neurogenesis occurs over a short period during mammalian embryonic development. These features have hampered the effort to understand how regionalization, cell divisions, and fate specification are coordinated and produce a wide array of nuclei that exhibit distinct patterns of gene expression and functions. Here, we performed in vivo clonal analysis to track the divisions of individual progenitor cells and spatial allocation of their progeny in the developing mouse thalamus. Quantitative analysis of clone compositions revealed evidence for sequential generation of distinct sets of thalamic nuclei based on the location of the founder progenitor cells. Furthermore, we identified intermediate progenitor cells that produced neurons populating more than one thalamic nuclei, indicating a prolonged specification of nuclear fate. Our study reveals an organizational principle that governs the spatial and temporal progression of cell divisions and fate specification and provides a framework for studying cellular heterogeneity and connectivity in the mammalian thalamus.

A distinct serum metabolic signature of distant metastatic papillary thyroid carcinoma.

BACKGROUND: Although the incidence rate for thyroid cancer seems to have begun stabilizing in recent years, an increased rate of advanced stage of this disease has been reported. Additionally, distant metastasis is one of the most important prognostic factors of patients with papillary thyroid carcinoma (PTC). Unfortunately, the underlying mechanisms of distant metastasis, as well as cell status like metabolism changes in distant metastatic tumours have not been clearly elucidated. OBJECTIVE: To identify serum metabolic signature of distant metastatic PTC. DESIGN, PATIENTS AND MEASUREMENTS: In this study, gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) was used to analyse the serum from 77 patients diagnosed with PTC (37 in distant metastasis group and 40 in ablation group). Principal component analysis (PCA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA) scores plots were used to analyse the data. RESULTS: Principal component analysis and OPLS-DA analyses demonstrated an evident trend of separation between 40 serum samples from the ablation group and 37 samples from distant metastasis group. A total of 31 metabolites were identified, which are related to amino acid, lipid, glucose, vitamin metabolism and diet/gut microbiota interaction. Pathway analysis showed "alanine, aspartate and glutamate metabolism" and "inositol phosphate metabolism" were the most relevant pathways. CONCLUSION: Serum metabolomics profiling could significantly discriminate papillary thyroid cancer patients according to distant metastasis. Potential metabolic aberration in distant metastatic PTC could be involved in different biological behaviours of tumour cells including proliferation, invasion/migration and immune escape. Diet/gut microbiota-produced metabolites could play an important role in these effects. This work may provide new clues to find the underlying mechanisms regarding the distant metastasis of PTC as well as potential adjuvant therapy targets.

[Phosphorus fractions, sorption characteristics and its release in the sediments of Yangtze Estuary Reservoir, China].

To analyze the sediment phosphorus (P) fractions and sorption characteristics and P release from sediment of reservoir in Yangtze estuary, the sediment was investigated during April, 2011 to January, 2012. Results of chemical fractionation analysis showed that total P (TP) content in sediment ranged from 535.07 to 910.9 mg x kg(-1), inorganic P (IP) was a dominant component of TP and the content of organic P (OP) was low. IP presented in the form of P bounded to calcium ( HCl-P) and dominated 75.57% of TP. The batch experiments showed that sediments had the maximum P adsorption capacity from 9.78 to 39.84 mg x kg(-1), sorption data fitted the modified Langmuir isotherm model. However, EPC0 ( equilibrium phosphorus concentration) in all sampling sites was higher than the soluble-reactive P concentration in water column, which was from 0.024-0.12 mg x L(-1). Accordingly, the sediments from those sampling sites would release phosphorus into the overlying water as a P release source. The maximum released amount from sediment was 11.03 mg x kg(-1) about 6 hours. Correlation between P released amount and NaOH-P was found (P < 0.01), and sediment P release would mainly originate from the NaOH-P, OP and HCl-P fraction. It is evident that the inherent phosphorus present in sediments would be a major threat to the water quality in Yangtze River estuary reservoir.

Acetylcholine-secreting cells improve age-induced memory deficits.

The present study examined whether aged rats with naturally occurring cognitive deficits in spatial learning and memory would benefit from local chronic supplementation of acetylcholine. Aged impaired and aged unimpaired rats were pretested in the water maze to characterize the extent of age-induced cognitive impairment. Groups were matched for extent of deficits. The animals subsequently received implants of either acetylcholine-releasing cells or control cells into the cortical and hippocampal target regions of the basal forebrain. One week postgrafting, spatial learning and memory were retested using the same behavioral procedure. All aged groups acquired the platform position more slowly than young controls. However, aged impaired rats grafted with acetylcholine-releasing cells performed significantly better than aged impaired rats with control grafts, and they did not differ from aged unimpaired groups. A spatial memory probe test revealed that memory for the escape platform location of the acetylcholine-grafted rats was significantly better than that of rats with control grafts and matched the performance of young controls. In vitro, biochemical and electrophysiological analyses of the engineered cells confirmed choline acetyltransferase activity and showed quantal release of acetylcholine from the transduced cells. In vivo, RT-PCR of microdissected grafts indicated that the engineered cells expressed the choline acetyltransferase transgene for up to 40 days postgrafting. These results indicate that locally restricted supplementation of acetylcholine into the two major target regions of the cholinergic basal forebrain of aged impaired rats ameliorates some age-related cognitive deficits.