Amniotic fluid stem cell extracellular vesicles promote fetal lung branching and cell differentiation in experimental congenital diaphragmatic hernia

Pulmonary hypoplasia secondary to congenital diaphragmatic hernia (CDH) is characterized by impaired branching morphogenesis and differentiation. We have previously demonstrated that administration of extracellular vesicles derived from rat amniotic fluid stem cells (AFSC-EVs) rescues development of hypoplastic lungs at the pseudoglandular and alveolar stages in rodent models of CDH. Herein, we tested whether AFSC-EVs exert their regenerative effects at the canalicular and saccular stages, as these are translationally relevant for clinical intervention. To induce fetal pulmonary hypoplasia, we gavaged rat dams with nitrofen at embryonic day 9.5 and demonstrated that nitrofen-exposed lungs had impaired branching morphogenesis, dysregulated signaling pathways relevant to lung development (FGF10/FGFR2, ROBO/SLIT, Ephrin, Neuropilin 1, beta-catenin) and impaired epithelial and mesenchymal cell marker expression at both stages. AFSC-EVs administered to nitrofen-exposed lung explants rescued airspace density and increased the expression levels of key factors responsible for branching morphogenesis. Moreover, AFSC-EVs rescued the expression of alveolar type 1 and 2 cell markers at both canalicular and saccular stages, and restored markers of club, ciliated epithelial, and pulmonary neuroendocrine cells at the saccular stage. AFSC-EV treated lungs also had restored markers of lipofibroblasts and PDGFRA+ cells to control levels at both stages. EV tracking showed uptake of AFSC-EV RNA cargo throughout the fetal lung and an mRNA-miRNA network analysis identified that several miRNAs responsible for regulating lung development processes were contained in the AFSC-EV cargo. These findings suggest that AFSC-EV based therapies hold potential for restoring fetal lung growth and maturation in babies with pulmonary hypoplasia secondary to CDH.

Developmental origins of cell heterogeneity in the human lung

The lung contains numerous specialized cell-types with distinct roles in tissue function and integrity. To clarify the origins and mechanisms generating cell heterogeneity, we created a first comprehensive topographic atlas of early human lung development. We report 83 cell states, several spatially-resolved developmental trajectories and predict cell interactions within defined tissue niches. We integrated scRNA-Seq and spatial transcriptomics into a web-based, open platform for interactive exploration. To illustrate the utility of our approach we show distinct states of secretory and neuroendocrine cells, largely overlapping with the programs activated either during lung fibrosis or small cell lung cancer progression. We define the origin of uncharacterized airway fibroblasts associated with airway smooth muscle in bronchovascular bundles, and describe a trajectory of Schwann cell progenitors to intrinsic parasympathetic neurons controlling bronchoconstriction. Our atlas provides a rich resource for further research and a reference for defining deviations from homeostatic and repair mechanisms leading to pulmonary diseases.

Challenges in treatment of a patient suffering from neuroendocrine tumor G1 of the hilar bile duct: a case report

Background Neuroendocrine tumors (NETs) arise from neuroendocrine cells and are extremely rare in the biliary tract. Currently, there are no guidelines for the diagnosis and treatment of biliary NETs. We presented a case with NETs G1 of the hilar bile duct and the challenges for her treatment. Case presentation A 24-year-old woman was presented to our department with painless jaundice and pruritus, and the preoperative diagnosis was Bismuth type II hilar cholangiocarcinoma. She underwent Roux-en-Y hepaticojejunostomy with excision of the extrahepatic biliary tree and radical lymphadenectomy. Unexpectedly, postoperative pathological and immunohistochemical examination indicated a perihilar bile duct NETs G1 with the microscopic invasion of the resected right hepatic duct. Then the patient received 3 cycles of adjuvant chemotherapy (Gemcitabine and tegafur-gimeracil-oteracil potassium capsule). At present, this patient has been following up for 24 months without recurrence or disease progression. Conclusion We know little of biliary NETs because of its rarity. There are currently no guidelines for the diagnosis and treatment of biliary NETs. We reported a case of perihilar bile duct NETs G1 with R1 resection, as far as we know this is the first report. More information about biliary NETs should be registered.

Mixed neuroendocrine-non-neuroendocrine neoplasm of the colon: case report

Mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) is defined as a tumor composed of cells originating from neuroendocrine cells in the embryonic intestine and elements of epithelial adenocarcinoma. To determine the differentiation grade of MiNEN, the proliferation index was used, for which at least 500 cells were examined. MiNEN is a rare neoplasm that is most frequently found in the lower gastrointestinal tract. We present a rare clinical case of surgical treatment of MiNEN of the ascending colon.

Model systems in SDHx-related pheochromocytoma/paraganglioma

Pheochromocytoma (PHEO) and paraganglioma (PGL) (together PPGL) are tumors with poor outcomes that arise from neuroendocrine cells in the adrenal gland, and sympathetic and parasympathetic ganglia outside the adrenal gland, respectively. Many follow germline mutations in genes coding for subunits of succinate dehydrogenase (SDH), a tetrameric enzyme in the tricarboxylic acid (TCA) cycle that both converts succinate to fumarate and participates in electron transport. Germline SDH subunit B (SDHB) mutations have a high metastatic potential. Herein, we review the spectrum of model organisms that have contributed hugely to our understanding of SDH dysfunction. In Saccharomyces cerevisiae (yeast), succinate accumulation inhibits alpha-ketoglutarate-dependent dioxygenase enzymes leading to DNA demethylation. In the worm Caenorhabditis elegans, mutated SDH creates developmental abnormalities, metabolic rewiring, an energy deficit and oxygen hypersensitivity (the latter is also found in Drosophila melanogaster). In the zebrafish Danio rerio, sdhb mutants display a shorter lifespan with defective energy metabolism. Recently, SDHB-deficient pheochromocytoma has been cultivated in xenografts and has generated cell lines, which can be traced back to a heterozygous SDHB-deficient rat. We propose that a combination of such models can be efficiently and effectively used in both pathophysiological studies and drug-screening projects in order to find novel strategies in PPGL treatment.

CK2 Phosphorylation Is Required for Regulation of Syntaxin 1A Activity in Ca2+-Triggered Release in Neuroendocrine Cells

The polybasic juxtamembrane region (5RK) of the plasma membrane neuronal SNARE, syntaxin1A (Syx), was previously shown by us to act as a fusion clamp in PC12 cells, as charge neutralization of 5RK promotes spontaneous and inhibits Ca2+-triggered release. Using a Syx-based FRET probe (CSYS), we demonstrated that 5RK is required for a depolarization-induced Ca+2-dependent opening (close-to-open transition; CDO) of Syx, which involves the vesicular SNARE synaptobrevin2 and occurs concomitantly with Ca2+-triggered release. Here, we investigated the mechanism underlying the CDO requirement for 5RK and identified phosphorylation of Syx at Ser-14 (S14) by casein kinase 2 (CK2) as a crucial molecular determinant. Thus, following biochemical verification that both endogenous Syx and CSYS are constitutively S14 phosphorylated in PC12 cells, dynamic FRET analysis of phospho-null and phospho-mimetic mutants of CSYS and the use of a CK2 inhibitor revealed that the S14 phosphorylation confers the CDO requirement for 5RK. In accord, amperometric analysis of catecholamine release revealed that the phospho-null mutant does not support Ca2+-triggered release. These results identify a functionally important CK2 phosphorylation of Syx that is required for the 5RK-regulation of CDO and for concomitant Ca2+-triggered release. Further, also spontaneous release, conferred by charge neutralization of 5RK, was abolished in the phospho-null mutant.

Histological Origin and Clinicopathological Analysis of Primary Ovarian Neuroendocrine Neoplasms

Purpose To investigate the histological origin and clinical and pathological features of primary ovarian neuroendocrine neoplasms. Methods We retrospectively analyzed nine cases of ovarian neuroendocrine neoplasms diagnosed at our hospital from January 2009 to January 2021. Results The mean age of the nine patients was 44.9 ± 15.2 years (range, 28–68 years). Six cases manifested ovarian carcinoid cancer, and the pathological types were insular and trabecular carcinoid; microscopic observation showed that the carcinoid components were limited and that stromal reaction was slight. Four cases showed teratomas, with the carcinoid components not displaying adjacent mucinous glands; and the other cases exhibited carcinoid cancer as the only tumor component, without adjacent or migratory epithelial components. The six patients were followed up for 76.6 ± 41.2 (6–123) months after resection, without disease. Two cases manifested adenocarcinoma admixed with neuroendocrine carcinoma, and the intermigration of neuroendocrine carcinoma and adenocarcinoma components could be observed; and one case was an isolated small cell neuroendocrine carcinoma with no epithelial proximity or migration observed. Adenocarcinoma admixed with neuroendocrine carcinoma and small-cell neuroendocrine carcinoma exhibited an obviously promoted interstitial reaction and damaging infiltration: these three patients underwent radical surgery supplemented by postoperative radiotherapy and chemotherapy, and follow-up lasted 34.6 ± 24.2 (7–52) months; two patients died and one showed recurrence. Conclusions Ovarian neuroendocrine neoplasms may reflect multiple tissue origins, carcinoid and simple neuroendocrine neoplasms with no adjacent, transitional epithelium, and may originate from original/transformed neuroendocrine cells or stem cells of the ovarian stroma. In addition, the adenocarcinoma admixed with neuroendocrine carcinoma may originate from dedifferentiated epithelium. The prognosis with carcinoid cancer is favorable, while the prognosis for neuroendocrine carcinoma is poor.

Time to Classify Tumours of the Stomach and the Kidneys According to Cell of Origin

Malignant tumours are traditionally classified according to their organ of origin and whether they are of epithelial (carcinomas) or mesenchymal (sarcomas) origin. By histological appearance the site of origin may often be confirmed. Using same treatment for tumours from the same organ is rational only when there is no principal heterogeneity between the tumours of that organ. Organ tumour heterogeneity is typical for the lungs with small cell and non-small cell tumours, for the kidneys where clear cell renal carcinoma (CCRCC) is the dominating type among other subgroups, and in the stomach with adenocarcinomas of intestinal and diffuse types. In addition, a separate type of neuroendocrine tumours (NETs) is found in most organs. Every cell type able to divide may develop into a tumour, and the different subtypes most often reflect different cell origin. In this article the focus is on the cells of origin in tumours arising in the stomach and kidneys and the close relationship between normal neuroendocrine cells and NETs. Furthermore, that the erythropoietin producing cell may be the cell of origin of CCRCC (a cancer with many similarities to NETs), and that gastric carcinomas of diffuse type may originate from the ECL cell, whereas the endodermal stem cell most probably gives rise to cancers of intestinal type.

Advanced imaging approaches to reveal molecular mechanisms governing neuroendocrine secretion

Identification of the molecular mechanisms governing neuroendocrine secretion and resulting intercellular communication is one of the great challenges of cell biology to better understand organism physiology and neurosecretion disruption-related pathologies such as hypertension, neurodegenerative or metabolic diseases. To visualize molecule distribution and dynamics below the diffraction limit, many imaging approaches have been developed and are still emerging. In this review, we provide an overview of the pioneering studies that use transmission electron microscopy, atomic force microscopy, total internal reflection microscopy and super-resolution microscopy in neuroendocrine cells to visualize molecular mechanisms driving neurosecretion processes, including exocytosis and associated fusion pores, endocytosis and associated recycling vesicles, and protein-protein/protein-lipid interactions. Furthermore, the potential and the challenges of these different advanced imaging approaches for application in the study of neuroendocrine cell biology are discussed, aiming to guide researchers to select the best approach for their specific purpose around the crucial but not yet fully understood neurosecretion process.

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH): A Case of Indolent Pulmonary Nodules Diagnosed with Robotic-Assisted Navigational Bronchoscopy

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is an atypical pulmonary disorder with limited understanding. Given the rare nature of this disease, it is essential to obtain adequate tissue pathology to confirm the diagnosis. This disease is mainly diagnosed in middle-aged, nonsmoking females, and it is now accepted as a precursor lesion to pulmonary carcinoid tumors. DIPNECH presents with characteristic radiographic and histologic findings, but its diagnosis, management, and prognosis are often underrecognized and poorly understood. Those with symptoms may present with shortness of breath, wheezing, and persistent cough and are often misdiagnosed with reactive airway disease. Pulmonary function testing may reveal airflow obstruction and air trapping. Imaging is characterized by multiple lung nodules, typically less than 5 mm in size, with a background mosaic attenuation on computed tomography imaging. Histologically, DIPNECH can be suspected based on the presence of hyperplastic neuroendocrine cells. DIPNECH is considered a precursor to invasive neuroendocrine tumor, and up to 50% of patients may have a well-differentiated neuroendocrine tumor at the time of presentation. Here, we present the case of a 46-year-old female with a history of ulcerative colitis on mesalamine who presented with a 6-month history of ongoing shortness of breath, chest tightness, wheezing, and cough. She was initially diagnosed with asthma before imaging later revealed as multiple pulmonary nodules with a diffuse mosaic pattern. Using robotic-assisted navigational bronchoscopy, she underwent sampling of a dominant 1.8 cm right middle lobe pulmonary nodule and pathology was consistent with low-grade neuroendocrine tumor.