Patch-Seq Links Single-Cell Transcriptomes to Human Islet Dysfunction in Diabetes

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Human Pancreatic Islet Isolation: Part I: Digestion and Collection of Pancreatic Tissue

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of glucose monitoring and new insulin formulations, many individuals still develop devastating secondary complications. Pancreatic islet transplantation can restore near normal glucose control in diabetic patients ¹, without the risk of serious hypoglycemic episodes that are associated with intensive insulin therapy. Providing sufficient islet mass is important for successful islet transplantation. However, donor characteristic, organ procurement and preservation affect the isolation outcome ². At University of Illinois at Chicago (UIC) we have developed a successful isolation protocol with an improved purification gradient ³. The program started in January 2004, and more than 300 isolations were performed up to November 2008. The pancreata were sent in cold preservation solutions (UW, University of Wisconsin or HTK, Histidine-Tryptophan Ketoglutarate) ^4-7 to the Cell Isolation Laboratory at UIC for islet isolation. Pancreatic islets were isolated using the UIC method, which is a modified version of the method originally described by Ricordi et al ⁸. Briefly, after cleaning the pancreas from the surrounding tissue, it was perfused with enzyme solution (Serva Collagenase + Neutral Protease or Sigma V enzyme). The distended pancreas was then transferred to the Ricordi digestion chamber, connected to a modified, closed circulation tubing system, and warmed up to 37°C. During the digestion, the chamber was shaken gently. Samples were taken continuously to monitor the digestion progress. Once free islets were detected under the microscope, the digestion was stopped by flushing cold (4°C) RPMI dilution solution (Mediatech, Herndon, VA) into the circulation system to dilute the enzyme. After being collected and washed in M199 media supplemented with human albumin, the tissue was sampled for pre-purification count and incubated with UW solution before purification. Purification process will be described in Part II: Purification and Culture of Human Islets.     

Gene regulatory networks in plants: learning causality from time and perturbation

The goal of systems biology is to generate models for predicting how a system will react under untested conditions or in response to genetic perturbations. This paper discusses experimental and analytical approaches to deriving causal relationships in gene regulatory networks.     

Epithelial Vegfa Specifies a Distinct Endothelial Population in the Mouse Lung

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Human Anti-fungal Th17 Immunity and Pathology Rely on Cross-Reactivity against Candida albicans

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Stem cell-based modeling and single-cell multiomics reveal gene-regulatory mechanisms underlying human skeletal development

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Mouse pancreatic acinar/ductlar tissue gives rise to epithelial cultures that are morphologically,biochemically, and functionally indistinguishable from interlobular duct cell cultures

Summary Most of the pancreatic exocrine epithelium consists of acinar and intralobular duct (ductular) cells, with the balance consisting of interlobular and main duct cells. Fragments of mouse acinar/ductular epithelium can be isolated by partial digestion with collagenase and purified by Ficoll density gradient centrifugation. We investigated whether previously developed culture conditions used for duct epithelium would result in the selective survival and proliferation of ductular cells from the acinar/ductular fragments. The fragments were cultured on nitrocellulose filters coated with extracellular matrix. After 2 to 4 wk the filters were covered with proliferating cells resembling parallel cultures of duct epithelium by the following criteria: protein/DNA ratio, light and electron microscopic appearance, the presence of duct markers (carbonic anhydrase [CA] activity, CA II mRNA, the cystic fibrosis transmembrane conductance regulator), the near absence of acinar cell markers (amylase and chymotrypsin), a similar polypeptide profile after sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the presence of spontaneous and secretin-stimulated electrogenic ion transport. Both duct and ductular epithelia formed fluid-filled cysts in collagen gels and both could be subcultured. We conclude that acinar/ductular tissue gives rise to ductular cells in culture by some combination of acinar cell death and/or transdifferentiation to a ductular phenotype, accompanied by proliferation of these cells and preexisting ductular cells. These cultures may be used to investigate the properties of this part of the pancreatic duct system, from which most of the pancreatic juice water and electrolytes probably originates.     

多发性骨髓瘤细胞株ARH—77恶性相关基因hMMTAG2的克隆和序列分析

为从人类多发性骨髓瘤细胞株中克隆新的恶性相关基因 ,构建人类多发性骨髓瘤细胞株ARH 77cDNA文库。从ARH 77细胞中提取mRNA并逆转录合成双链cDNA ,经PCR扩增后 ,插入表达载体 ,得到ARH 77细胞cDNA表达文库。将文库菌落印迹至尼龙膜 ,分区培养提取质粒DNA ,建立基因池 ,并分别转染NIH/ 3T3细胞。经G418筛选并计集落数 ,选择克隆数最多的基因池进入第二轮。如此反复进行。通过测序 ,排除所有已知的癌基因、抑瘤基因、细胞因子及其受体 ,获得了有转化活性的cDNA克隆A6 2 17。进一步使用RACE技术对 5′端进行快速扩增 ,获得全长为 130 0bp的cDNA序列 ,该基因由 8个外显子组成 ,编码产物为 2 6 3个氨基酸组成的多肽链。将该基因暂时命名为多发性骨髓瘤转化基因 2 (tumor associatedgene 2fromhumanmultiplemyeloma ,hMMTAG2 )。该基因定位于人类染色体 1q42 .13。生物信息学分析发现 ,hMMTAG2编码有多个蛋白激酶的磷酸化位点、N 肉豆蔻酸化位点及核定位信号 ,提示该基因的表达产物可能是细胞核内的一种信号分子。