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Human brain organoid techniques have rapidly advanced to facilitate investigating human brain development and diseases. These efforts have largely focused on generating telencephalon due to its direct relevance in a variety of forebrain disorders. Despite its importance as a relay hub between cortex and peripheral tissues, the investigation of three-dimensional (3D) organoid models for the human thalamus has not been explored. Here, we describe a method to differentiate human embryonic stem cells (hESCs) to thalamic organoids (hThOs) that specifically recapitulate the development of thalamus. Single-cell RNA sequencing revealed a formation of distinct thalamic lineages, which diverge from telencephalic fate. Importantly, we developed a 3D system to create the reciprocal projections between thalamus and cortex by fusing the two distinct region-specific organoids representing the developing thalamus or cortex.Our study provides a platform for understanding human thalamic development and modeling circuit organizations and related disorders in the brain.(C) qPCR analysis for expressions of regional markers in developing hThOs, hMGEOs, and hCOs. Each data point represents expressions in pooled batch of 3-4 organoids, and 3 batches were collected for analysis. Mean ± SD is shown. *p < 0.05, **p < 0.01, ***p < 0.001. (D) Immunostaining for MAP2 and thalamic marker TCF7L2 in day 41 hThO, hCO, and hMGEO. The scale bar represents 250 mm. (E) Immunostaining for thalamic and cortical progenitor marker PAX6, and cortical marker TBR1 in day 41 hThO, hCO, and hMGEO. The scale bar represents 250 mm. See also Figure S1.

Rett syndrome (RTT) is one of the most prevalent female neurodevelopmental disorders that cause severe mental retardation. Mutations in methyl CpG binding protein 2 (MeCP2) are mainly responsible for RTT. Patients with classical RTT exhibit normal development until age 6-18 mo, at which point they become symptomatic and display loss of language and motor skills, purposeful hand movements, and normal head growth. Murine genetic models and postmortem human brains have been used to study the disease and enable the molecular dissection of RTT. In this work, we applied a recently developed reprogramming approach to generate a novel in vitro human RTT model. Induced pluripotent stem cells (iPSCs) were derived from RTT fibroblasts by overexpressing the reprogramming factors OCT4, SOX2, KLF4, and MYC. Intriguingly, whereas some iPSCs maintained X chromosome inactivation, in others the X chromosome was reactivated. Thus, iPSCs were isolated that retained a single active X chromosome expressing either mutant or WT MeCP2, as well as iPSCs with reactivated X chromosomes expressing both mutant and WT MeCP2. When these cells underwent neuronal differentiation, the mutant monoallelic or biallelelic RTT-iPSCs displayed a defect in neuronal maturation consistent with RTT phenotypes. Our in vitro model of RTT is an important tool allowing the further investigation of the pathophysiology of RTT and the development of the curative therapeutics.

Complement-C1q TNF-related protein 1 (CTRP1), a member of the CTRP superfamily, is expressed at high levels in adipose tissues of obese Zucker diabetic fatty (fa/fa) rats, and CTRP1 expression is induced by proinflammatory cytokines, including TNF-alpha and IL-1beta. In the present study, we investigated stimulation of aldosterone production by CTRP1, since it was observed that CTRP1 was specifically expressed in the zona glomerulosa of the adrenal cortex, where aldosterone is produced. Increased aldosterone production by CTRP1 in cells of the human adrenal cortical cell line H295R was dose-dependent. Expression levels of aldosterone synthase CYP11B2 were examined to investigate the molecular mechanisms by which CTRP1 enhances the production of aldosterone. The expression of CYP11B2 was greatly increased by treatment with CTRP1, as was the expression of the transcription factors NGFIB and NURR1, which play critical roles in stimulation of CYP11B2 gene expression. It was also revealed that angiotensin II-induced aldosterone production is, at least in part, mediated by the stimulation of CTRP1 secretion, not by the increase of CTRP1 mRNA transcription. In addition, the levels of CTRP1 were significantly up-regulated in hypertensive patients' serum. As CTRP1 was highly expressed in obese subjects as well as up-regulated in hypertensive patients, CTRP1 may be a newly identified molecular link between obesity and hypertension.

Background Supravalvular aortic stenosis (SVAS) is caused by mutations in the elastin (ELN) gene and is characterized by abnormal proliferation of vascular smooth muscle cells (SMCs) that can lead to narrowing or blockage of the ascending aorta and other arterial vessels. Availability of patient-specific SMCs may facilitate studying disease mechanisms and developing novel therapeutic interventions. Methods and Results Here, we report the development of a human induced pluripotent stem cell (iPSC) line from a patient with SVAS caused by the premature termination in exon 10 of the ELN gene due to an exon 9 4-nucleotide insertion. We showed that SVAS iPSC-derived SMCs (iPSC-SMCs) had significantly fewer organized networks of smooth muscle alpha actin (SM α-actin) filament bundles, a hallmark of mature contractile SMCs, compared to control iPSC-SMCs. Addition of elastin recombinant protein or enhancement of small GTPase RhoA signaling was able to rescue the formation of SM α-actin filament bundles in SVAS iPSC-SMCs. Cell counts and BrdU analysis revealed a significantly higher proliferation rate in SVAS iPSC-SMCs than control iPSC-SMCs. Furthermore, SVAS iPSC-SMCs migrated at a markedly higher rate to the chemotactic agent platelet-derived growth factor (PDGF) in comparison with the control iPSC-SMCs. We also provided evidence that elevated activity of extracellular signal-regulated kinase 1/2 (ERK1/2) is required for hyper-proliferation of SVAS iPSC-SMCs. The phenotype was confirmed in iPSC-SMCs generated from a patient with deletion of elastin due to Williams-Beuren syndrome (WBS). Conclusions Thus, SVAS iPSC-SMCs recapitulate key pathological features of patients with SVAS and may provide a promising strategy to study disease mechanisms and to develop novel therapies.

Innervation plays a pivotal role as a driver of tissue and organ development as well as a means for their functional control and modulation. Therefore, innervation should be carefully considered throughout the process of biofabrication of engineered tissues and organs. Unfortunately, innervation has generally been overlooked in most non-neural tissue engineering applications, in part due to the intrinsic complexity of building organs containing heterogeneous native cell types and structures. To achieve proper innervation of engineered tissues and organs, specific host axon populations typically need to be precisely driven to appropriate location(s) within the construct, often over long distances. As such, neural tissue engineering and/or axon guidance strategies should be a necessary adjunct to most organogenesis endeavors across multiple tissue and organ systems. To address this challenge, our team is actively building axon-based "living scaffolds" that may physically wire in during organ development in bioreactors and/or serve as a substrate to effectively drive targeted long-distance growth and integration of host axons after implantation. This article reviews the neuroanatomy and the role of innervation in the functional regulation of cardiac, skeletal, and smooth muscle tissue and highlights potential strategies to promote innervation of biofabricated engineered muscles, as well as the use of "living scaffolds" in this endeavor for both in vitro and in vivo applications. We assert that innervation should be included as a necessary component for tissue and organ biofabrication, and that strategies to orchestrate host axonal integration are advantageous to ensure proper function, tolerance, assimilation, and bio-regulation with the recipient post-implant.

Purpose of review The lack of effective treatments for various neurodegenerative disorders has placed huge burdens on society. We review the current status application of pluripotent stem cells (iPSCs) technology for the cellular therapy, drug screening and in vitro modeling of neurodegenerative diseases. Recent findings Disease specific iPSCs were derived from patients of several major neurodegenerative diseases, including Parkison' disease, Alzheimer's disease, amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). Differentiation of the SMA-iPSCs into neurons showed the recapitulation of the in vivo phenotypes, allowing us the future use of drug screening. The murine model of Parkinson's transplanted with human iPSCs showed the functional recovery, showing the potential of iPSC as cell therapy. Direct conversion to neurons was succeeded from skin fibroblasts of Alzheimer's patients. Summary We summarize the recent progress in using iPSCs for neurodegenerative diseases, and provide a future perspective in this field.

SummaryInduced pluripotent stem cells (iPSCs) acquire embryonic stem cell (ESC)-like epigenetic states, including the X chromosome. Previous studies reported that human iPSCs retain the inactive X chromosome of parental cells, or acquire two active X chromosomes through reprogramming. Most studies investigated the X chromosome states in established human iPSC clones after completion of reprogramming. Thus, it is still not fully understood when and how the X chromosome reactivation occurs during reprogramming. Here, we report a dynamic change in the X chromosome state throughout reprogramming, with an initial robust reactivation of the inactive X chromosome followed by an inactivation upon generation of nascent iPSC clones. iPSCs with two active X chromosomes or an eroded X chromosome arise in passaging iPSCs. These data provide important insights into the plasticity of the X chromosome of human female iPSCs and will be crucial for the future application of such cells in cell therapy and X-linked disease modeling.