SummaryIn vivo studies of human brain cellular function face challenging ethical and practical difficulties. Animal models are typically used but display distinct cellular differences. One specific example is astrocytes, recently recognized for contribution to neurological diseases and a link to the genetic risk factor apolipoprotein E (APOE). Current astrocytic in vitro models are questioned for lack of biological characterization. Here, we report human induced pluripotent stem cell (hiPSC)-derived astroglia (NES-Astro) developed under defined conditions through long-term neuroepithelial-like stem (ltNES) cells. We characterized NES-Astro and astrocytic models from primary sources, astrocytoma (CCF-STTG1), and hiPSCs through transcriptomics, proteomics, glutamate uptake, inflammatory competence, calcium signaling response, and APOE secretion. Finally, we assess modulation of astrocyte biology using APOE-annotated compounds, confirming hits of the cholesterol biosynthesis pathway in adult and hiPSC-derived astrocytes. Our data show large diversity among astrocytic models and emphasize a cellular context when studying astrocyte biology.

Cell-based models of the blood-brain barrier (BBB) are important for increasing the knowledge of BBB formation, degradation and brain exposure of drug substances. Human models are preferred over animal models because of interspecies differences in BBB structure and function. However, access to human primary BBB tissue is limited and has shown degeneration of BBB functions in vitro. Human induced pluripotent stem cells (iPSCs) can be used to generate relevant cell types to model the BBB with human tissue. We generated a human iPSC-derived model of the BBB that includes endothelial cells in coculture with pericytes, astrocytes and neurons. Evaluation of barrier properties showed that the endothelial cells in our coculture model have high transendothelial electrical resistance, functional efflux and ability to discriminate between CNS permeable and non-permeable substances. Whole genome expression profiling revealed transcriptional changes that occur in coculture, including upregulation of tight junction proteins, such as claudins and neurotransmitter transporters. Pathway analysis implicated changes in the WNT, TNF, and PI3K-Akt pathways upon coculture. Our data suggest that coculture of iPSC-derived endothelial cells promotes barrier formation on a functional and transcriptional level. The information about gene expression changes in coculture can be used to further improve iPSC-derived BBB models through selective pathway manipulation. Stem Cells 2018.

ADAM9 levels are increased in COPD lungs and linked to key clinical variables. Adam9 promotes emphysema development, and large and small airway disease in mice. Inhibition of ADAM9 could be a therapeutic approach for multiple COPD phenotypes.

Identification of small molecules with the potential to selectively proliferate cardiac progenitor cells (CPCs) will aid our understanding of the signaling pathways and mechanisms involved and could ultimately provide tools for regenerative therapies for the treatment of post-MI cardiac dysfunction. We have used an in vitro human induced pluripotent stem cellderived CPC model to screen a 10,000-compound library containing molecules representing different target classes and compounds reported to modulate the phenotype of stem or primary cells. The primary readout of this phenotypic screen was proliferation as measured by nuclear count. We identified retinoic acid receptor (RAR) agonists as potent proliferators of CPCs. The CPCs retained their progenitor phenotype following proliferation and the identified RAR agonists did not proliferate human cardiac fibroblasts, the major cell type in the heart. In addition, the RAR agonists were able to proliferate an independent source of CPCs, HuES6. The RAR agonists had a time-of-differentiation-dependent effect on the HuES6-derived CPCs. At 4 days of differentiation, treatment with retinoic acid induced differentiation of the CPCs to atrial cells. However, after 5 days of differentiation treatment with RAR agonists led to an inhibition of terminal differentiation to cardiomyocytes and enhanced the proliferation of the cells. RAR agonists, at least transiently, enhance the proliferation of human CPCs, at the expense of terminal cardiac differentiation. How this mechanism translates in vivo to activate endogenous CPCs and whether enhancing proliferation of these rare progenitor cells is sufficient to enhance cardiac repair remains to be investigated.

Astrocytes play important roles in the development, maintenance and function of neural circuits. We have studied the astrocytic cytoarchitecture of the adult rat cochlear nuclei using a monoclonal antibody against glial fibrillary acidic protein, a well-known intermediate filament of the cytoskeleton of the glial cells. The cochlear nuclear complex is the first central step in the ascending auditory pathway. The morphology and distribution of astrocytes, as well as the relationship of astroglial processes with neurons, have been found to be different in the three main subdivisions of the cochlear nuclei and could be related to their function.

Follicular Thyroid Carcinoma (FTC) accounts for 12% of thyroid cancers. It is most common in women between the ages of 40-60 years old. Although typically diagnosed after incidental palpation or via imaging obtained for other purposes, up to 15% of FTC may exhibit distant metastasis at the time of diagnosis. We present a case which required an interdisciplinary approach to lead to the correct diagnosis. A 49 year-old male presented with an orange-sized lump on his head. He was referred to a tertiary hospital for further evaluation. Brain MRI showed an infiltrative mass within the right parietal bone with extracalvarial, epidural and intraparenchymal extension. He underwent craniotomy for skull tumor resection and pathology revelead a metastatic adenocarcinoma of unknown origin. Pan-CT scanning revealed a 5 cm hypervascular complex nodule in the right thyroid lobe. PET showed uptake in this mass. Fine Needle Aspiration was consistent with FTC. Clusters of tumor cells from the bone surgical sample were positive for CK7, PAX8 and negative for PSA, CK20, PSAP, TTF1, CDX2 and Hepar. After comparison between brain and thyroid samples, a diagnosis of metastatic FTC was corroborated. Foundation testing was sent to guide further therapy. Programmed death-ligand 1 (PD-L1) results were discordant between samples, with the metastatic tissue showing frank 60% positivity, compared to the scant 5% expression at the primary tumor. The most common molecular alterations in FTC are RAS and PAX-8-PPAR gamma1 point mutations. When suspecting a primary tumor of thyroid origin, in the setting of an adenocarcinoma of unknown origin, immunohistochemistry (IHC) is crucial for accurate diagnosis. FTC typically exhibits distinct IHC patterns for markers such as TGB, HBME-1, PAX8, CD-56 and galectin-3. Several characteristics such as degree of angioinvasion and TERT mutations have been linked to greater risks of metastasis and poor prognosis. More recently, PD-L1 was found to be highly expressed in a subset of patients with advanced thyroid cancer, such as follicular and anaplastic thyroid carcinoma. The presence of PD-L1 expression may guide our therapeutic approach towards FTC in the future. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

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Prolactin is a pituitary hormone that functions in breast development and milk production in women and also plays an important role in immunoregulation and human immune responses, including autoimmune diseases. Macroprolactin, known as “big-big prolactin”, is due to the presence of marked hyperprolactinemia associated with evidence of prolactin-Ig (typically IgG4 or less frequently IgA) circulating complexes. We describes a case of 51 year-old female, with more than a 4 year history of reported hyperprolcatinemia who was treated with Cabergoline 0.5 mg weekly. Prior to treatment, she reported menses every 30-40 days, but denied galactorrhea or symptoms of sellar mass effect. Our patient had mildly elevated prolactin levels of 40-50 ng/dl. Her Thyroid function test were within normal limits. Patient had two pituitary MRIs in 2017 and 2019 which did not show sellar abnormalities. Prior to cabergolibe initiation, she was diagnosed with RS3PE syndrome (Remitting seronegative symmetrical synovitis with pitting edema) due to bilateral swelling in the dorsum of her hands. She was found to have hypergammaglobulinemia which was related to IgA elevation from chronic inflammation. Further investigation showed actual bio-active monomeric prolactin level was normal (4.8 ng/dl) and macroprolactin elevation from hypergammagolbulinemia. Before diagnosing her paraproteinemia and her macroprolactin predominance, she had received years of dopamine agonist therapy which was discontinued after diagnosis. We report a novel association of IgA predominant hypergammaglobulinemia from a chronic rheumatologic condition, leading to a misdiagnosed hyperprolcatinemia. Care should be taken to determine monomeric Prolactin levels prior to treatment, specially when symptoms are equivocal and/or imaging studies are negative.