WITHDRAWN: Conditional control of pancreatic progenitor maintenance and differentiation by FGF10 uncovers an endocrine-specific competence window in development

Gene therapy and transgenic research have advanced quickly in recent years due to the development of CRISPR technology. The rapid development of CRISPR technology has been largely benefited by chemical engineering. Firstly, chemical or synthetic substance enables spatiotemporal and conditional control of Cas9 or dCas9 activities. It prevents the leaky expression of CRISPR components, as well as minimizes toxicity and off-target effects. Multi-input logic operations and complex genetic circuits can also be implemented via multiplexed and orthogonal regulation of target genes. Secondly, rational chemical modifications to the sgRNA enhance gene editing efficiency and specificity by improving sgRNA stability and binding affinity to on-target genomic loci, and hence reducing off-target mismatches and systemic immunogenicity. Chemically-modified Cas9 mRNA is also more active and less immunogenic than the native mRNA. Thirdly, nonviral vehicles can circumvent the challenges associated with viral packaging and production through the delivery of Cas9-sgRNA ribonucleoprotein complex or large Cas9 expression plasmids. Multi-functional nanovectors enhance genome editing in vivo by overcoming multiple physiological barriers, enabling ligand-targeted cellular uptake, and blood-brain barrier crossing. Chemical engineering can also facilitate viral-based delivery by improving vector internalization, allowing tissue-specific transgene expression, and preventing inactivation of the viral vectors in vivo. This review aims to discuss how chemical engineering has helped improve existing CRISPR applications and enable new technologies for biomedical research. The usefulness, advantages, and molecular action for each chemical engineering approach are also highlighted.

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Nicotinamide promotes pancreatic differentiation through the dual inhibition of CK1 and ROCK kinases in human embryonic stem cells

Stem Cell Research & Therapy ◽

10.1186/s13287-021-02426-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yumeng Zhang ◽

Jiaqi Xu ◽

Zhili Ren ◽

Ya Meng ◽

Weiwei Liu ◽

...

Keyword(s):

Stem Cells ◽

Cell Fate ◽

Human Embryonic Stem Cells ◽

Embryonic Stem ◽

Cell Fate Determination ◽

Rna Seq ◽

Pancreatic Cell ◽

Pancreatic Progenitor ◽

Pancreatic Progenitors ◽

Rock Inhibition

Abstract Background Vitamin B3 (nicotinamide) plays important roles in metabolism as well as in SIRT and PARP pathways. It is also recently reported as a novel kinase inhibitor with multiple targets. Nicotinamide promotes pancreatic cell differentiation from human embryonic stem cells (hESCs). However, its molecular mechanism is still unclear. In order to understand the molecular mechanism involved in pancreatic cell fate determination, we analyzed the downstream pathways of nicotinamide in the derivation of NKX6.1+ pancreatic progenitors from hESCs. Methods We applied downstream modulators of nicotinamide during the induction from posterior foregut to pancreatic progenitors, including niacin, PARP inhibitor, SIRT inhibitor, CK1 inhibitor and ROCK inhibitor. The impact of those treatments was evaluated by quantitative real-time PCR, flow cytometry and immunostaining of pancreatic markers. Furthermore, CK1 isoforms were knocked down to validate CK1 function in the induction of pancreatic progenitors. Finally, RNA-seq was used to demonstrate pancreatic induction on the transcriptomic level. Results First, we demonstrated that nicotinamide promoted pancreatic progenitor differentiation in chemically defined conditions, but it did not act through either niacin-associated metabolism or the inhibition of PARP and SIRT pathways. In contrast, nicotinamide modulated differentiation through CK1 and ROCK inhibition. We demonstrated that CK1 inhibitors promoted the generation of PDX1/NKX6.1 double-positive pancreatic progenitor cells. shRNA knockdown revealed that the inhibition of CK1α and CK1ε promoted pancreatic progenitor differentiation. We then showed that nicotinamide also improved pancreatic progenitor differentiation through ROCK inhibition. Finally, RNA-seq data showed that CK1 and ROCK inhibition led to pancreatic gene expression, similar to nicotinamide treatment. Conclusions In this report, we revealed that nicotinamide promotes generation of pancreatic progenitors from hESCs through CK1 and ROCK inhibition. Furthermore, we discovered the novel role of CK1 in pancreatic cell fate determination.

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MFng Is Dispensable for Mouse Pancreas Development and Function

Molecular and Cellular Biology ◽

10.1128/mcb.01644-08 ◽

2009 ◽

Vol 29 (8) ◽

pp. 2129-2138 ◽

Cited By ~ 18

Author(s):

Per Svensson ◽

Ingela Bergqvist ◽

Stefan Norlin ◽

Helena Edlund

Keyword(s):

Cell Differentiation ◽

Notch Signaling ◽

Pancreas Development ◽

Loss Of Function ◽

Pancreatic Cell ◽

Targeted Deletion ◽

Mouse Pancreas ◽

Pancreatic Progenitor ◽

Pancreatic Progenitor Cells ◽

And Function

ABSTRACT Notch signaling regulates pancreatic cell differentiation, and mutations of various Notch signaling components result in perturbed pancreas development. Members of the Fringe family of β1,3-N-acetylglucosaminyltransferases, Manic Fringe (MFng), Lunatic Fringe (LFng), and Radical Fringe (RFng), modulate Notch signaling, and MFng has been suggested to regulate pancreatic endocrine cell differentiation. We have characterized the expression of the three mouse Fringe genes in the developing mouse pancreas between embryonic days 9 and 14 and show that the expression of MFng colocalized with the proendocrine transcription factor Ngn3. In contrast, the expression of LFng colocalized with the exocrine marker Ptf1a, whereas RFng was not expressed. Moreover, we show that expression of MFng is lost in Ngn3 mutant mice, providing evidence that MFng is genetically downstream of Ngn3. Gain- and loss-of-function analyses of MFng by the generation of mice that overexpress MFng in early pancreatic progenitor cells and mice with a targeted deletion of MFng provide, however, evidence that MFng is dispensable for pancreas development and function, since no pancreatic defects in these mice were observed.

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