The trident of the pancreatic duct : stemness, morphogenesis and endocrinogenesis

Different subtypes of diabetes are all featured by the deterioration and loss of functional β-cell. Currently, there is still lack of therapeutic strategies to cure diabetes. However, harnessing the innate stem cell population to become functional β-cell could be a potential way for future treatment. Mammalian animals, including mouse and human, can barely replenish the lost β-cell in the disease state; however, early vertebrates, especially zebrafish, has astonishing tissue regeneration capacity. In particular, zebrafish can quickly recover from the extreme β-cell loss and recovery body glucose level very quickly. Understanding the underlying cellular and molecular events is pivotal for the drug discovery in translational studies to treat diabetes. In Paper I, we introduced a compound, named CID661578, which we identified from a large- scale chemical screening experiment. Combining yeast hybrid assay, biochemistry experiments, polysome sequencing, single-cell RNA-seq and genetic zebrafish mutant, we confirmed that mknk2b in zebrafish and MNK2 in human are the major functional target. Functional testing indicated that CID661578 can induce duct-to-β-cell neogenesis in both zebrafish and neonatal pig islet. In Paper II, we introduced a novel CRISPR/Cas9 knock-in method to generate zebrafish lines for multiple utility (i.e. cell labeling and lineage tracing). We creatively used double-stranded DNA with 5’ modification as the donor. Such clone-free, one-step knock-in strategy allow researchers to target different loci in a quick and scalable fashion. Using the newly generated lines, we are able to delineate the developmental paths of zebrafish pancreas and liver and explore the origins of the regenerative hepatocytes under different injury conditions. In Paper III, the newly developed knock-in tools allow us to decipher the developmental paths of zebrafish endocrinogenesis in normal and β-cell ablation conditions. Combining single-cell RNA-seq, lineage tracing, cell targeted ablation, immunofluorescence, in situ hybridization, we identified a previously unrecognized ductal heterogeneity in zebrafish pancreas as well as the endocrine precursor cells during β-cell development. We delineate the key cellular and molecular events in β-cell differentiation and de-differentiation and pinpoint the distinct origins of β-cells during the development and regenerative conditions. This study offers a good resource and provides novel mechanistic insights into β-cell development and regeneration in zebrafish

Efficient knock-in method enabling lineage tracing in zebrafish

Here we attached the supplementary files that support our data which has been published in Biorxiv (https://www.biorxiv.org/content/10.1101/2022.07.15.500272v1). These include the key resource table with all the detailed information of the reagents, plasmid maps as well as the Sanger sequencing results showing the in-frame integration without any gene disruption. We welcome any further discussions and would like share the constructs upon request. If you have any further questions, please contact: Jiarui Mi ([email protected]) and Dr. Olov Andersson ([email protected]

A New Phenomenological Model for Single Particle Erosion of Plastic Materials

A phenomenological model for single particle erosion (SPE) of plastic materials was constructed based on the Hertzian contact theory and conservation of momentum to solve the particle impact erosion. The extrusion deformation and contact time of materials in three processes of wall elastic extrusion, elastic-plastic extrusion, and elastic recovery were discussed. Later, the critical angle for sliding contact between the particle and metal surface was calculated according to the impact angle of a particle and the corresponding critical sliding friction force of the particle. The wall indentation depths under sliding contact and no sliding contact were compared. Finally, the erosion volume of materials by impact of a single particle was gained. Moreover, a contrastive analysis on calculation results was carried out by using the gas-solid jet erosion experiment. Contact time, normal and tangential deformations of materials, as well as material erosion under sliding contact and no sliding contact in two processes of particle extrusion and rebound were gained from calculation and experiment. The constructed model showed a good agreement without involving too many empirical coefficients

Does previous cesarean section influence neonatal birth weight? A path analysis in China

BackgroundSince the One-child Policy was revised to a Two-child policy in 2013, the number of pregnancies with previous cesarean section suddenly increased in China. The aim of this study was to test if a previous cesarean section influenced the neonatal birth weight under Chinese background.MethodsA retrospective study was conducted. Path analysis was used to test the hypothesized model for the association among previous cesarean section, placenta previa, gestational age and neonatal birth weight. Comparative fit index, the root-mean-square error of approximation and weighted root-mean-square residual were used to evaluate the model fit.Results3466 electronic records for second pregnancies met the criteria; a modified model was established (the root-mean-square error of approximation=0.049, comparative fit index=0.992, weighted root-mean-square residual=0.960). The effects of previous cesarean section on neonatal birth weight were mediated via four paths. The direct effects (coefficient: 0.056) showed opposite signs compared to indirect effects (coefficient: -0.127) in this path analysis. It meant that the negative effects of the previous cesarean section were suppressed by other factors which bring positive effects.ConclusionThis study showed that previous cesarean section had negative effects on neonatal birth weight with increasing incidence of placenta previa and preterm birth. But these effects were suppressed by other positive factors, such as maternal body mass index, just after the child policy updated in China

Plasma campesterol and ABCG5/ABCG8 gene loci on the risk of cholelithiasis and cholecystitis: evidence from Mendelian randomization and colocalization analyses

Abstract The causal relationships between plasma metabolites and cholelithiasis/cholecystitis risks remain elusive. Using two-sample Mendelian randomization, we found that genetic proxied plasma campesterol level showed negative correlation with the risk of both cholelithiasis and cholecystitis. Furthermore, the increased risk of cholelithiasis is correlating with the increased level of plasma campesterol. Lastly, genetic colocalization study showed that the leading SNP, rs4299376, which residing at the ABCG5/ABCG8 gene loci, was shared by plasma campesterol level and cholelithiasis, indicating that the aberrant transportation of plant sterol/cholesterol from the blood stream to the bile duct/gut lumen might be the key in preventing cholesterol gallstone formation

Additional file 1 of Plasma campesterol and ABCG5/ABCG8 gene loci on the risk of cholelithiasis and cholecystitis: evidence from Mendelian randomization and colocalization analyses

Additional file 1: Fig. S1 Heatmap showing the causal estimates of metabolites (with valid SNPs as instrumental variables > 3) on the risk of cholelithiasis and cholecystitis using IVW random effect model. The p-value is adjusted using Benjamini–Hochberg method (known as FDR). FDR, false discovery rate; R9, FinnGen Release 9; UKBB, UK Bioban

Effects of editing DFR genes on flowers, leaves, and roots of tobacco

Abstract Background DFR is a crucial structural gene in plant flavonoid and polyphenol metabolism, and DFR knockout (DFR-KO) plants may have increased biomass accumulation. It is uncertain whether DFR-KO has comparable effects in tobacco and what the molecular mechanism is. We employed the CRISPR/Cas9 method to generate a knockout homozygous construct and collected samples from various developmental phases for transcriptome and metabolome detection and analysis. Results DFR-KO turned tobacco blossoms white on homozygous tobacco (Nicotiana tabacum) plants with both NtDFR1 and NtDFR2 knockout. RNA-seq investigation of anthesis leaf (LF), anthesis flower (FF), mature leaf (LM), and mature root (RM) variations in wild-type (CK) and DFR-KO lines revealed 2898, 276, 311, and 101 differentially expressed genes (DEGs), respectively. DFR-KO primarily affected leaves during anthesis. According to KEGG and GSEA studies, DFR-KO lines upregulated photosynthetic pathway carbon fixation and downregulated photosystem I and II genes. DFR-KO may diminish tobacco anthesis leaf photosynthetic light reaction but boost dark reaction carbon fixation. DFR-KO lowered the expression of pathway-related genes in LF, such as oxidative phosphorylation and proteasome, while boosting those in the plant–pathogen interaction and MAPK signaling pathways, indicating that it may increase biological stress resistance. DFR-KO greatly boosted the expression of other structural genes involved in phenylpropanoid production in FF, which may account for metabolite accumulation. The metabolome showed that LF overexpressed 8 flavonoid metabolites and FF downregulated 24 flavone metabolites. In DFR-KO LF, proteasome-related genes downregulated 16 amino acid metabolites and reduced free amino acids. Furthermore, the DEG analysis on LM revealed that the impact of DFR-KO on tobacco growth may progressively diminish with time. Conclusion The broad impact of DFR-KO on different phases and organs of tobacco development was thoroughly and methodically investigated in this research. DFR-KO decreased catabolism and photosynthetic light reactions in leaves during the flowering stage while increasing carbon fixation and disease resistance pathways. However, the impact of DFR-KO on tobacco growth steadily declined as it grew and matured, and transcriptional and metabolic modifications were consistent. This work offers a fresh insight and theoretical foundation for tobacco breeding and the development of gene-edited strains