Supraclavicular versus infraclavicular approach for ultrasound-guided right subclavian venous catheterisation: a randomised controlled non-inferiority trial

Infraclavicular and supraclavicular approaches are used for subclavian venous catheterisation. We hypothesised that the supraclavicular approach is non-inferior to the infraclavicular approach in terms of safety during ultrasound-guided right subclavian venous catheterisation. We randomly allocated 401 neurosurgical patients undergoing ultrasound-guided right subclavian venous catheterisation into supraclavicular (n = 200) and infraclavicular (n = 201) groups. We assessed catheterisation-related complications (primary outcome measure) including catheter misplacement and mechanical complications (arterial puncture, haematoma formation, pneumothorax and haemothorax). We also recorded catheterisation success rates and time required for venous puncture and catheterisation. The number (proportion) of patients with catheterisation-related complications was six (3.0%) in the supraclavicular group and 27 (13.4%) in the infraclavicular group, mean difference (95%CI) -10.4% (-15.7 to -5.1%), p < 0.001, with a significant difference also seen for catheter misplacement. Except for a shorter time (median (IQR [range]) required for venous puncture in the supraclavicular group, being 9 (6-20 [2-138]) vs. 13 (8-20 [3-99]) s, the incidence of mechanical complications and other catheterisation characteristics were similar between the two groups. We recommend the supraclavicular approach for ultrasound-guided right subclavian venous catheterisation.

CRISPR-Mediated Endogenous Activation of Fibroin Heavy Chain Gene Triggers Cellular Stress Responses in Bombyx mori Embryonic Cells

Simple Summary

Based on a CRISPRa approach, activating endogenous fibroin heavy chain (FibH) gene expression in Bombyx mori embryonic (BmE) cells, which was driven by a combination of the dCas9-VPR (a tripartite activator, composed of VP64, p65, and Rta) and the sgRNA targeting to the promoter of FibH gene, was performed for investigating the biological roles of FibH in the development of silk gland cells. The activation of the endogenous FibH gene lead to up-regulation of cellular stress responses-related genes, which suggested a significant positive correlation between activated FibH gene expression and cellular stress responses. Moreover, the present findings might provide a potential model for studying the cellular stress responses caused by silk secretion disorder and lay a foundation for the understanding of silk gland development in silk-spinning insects.

Abstract

The silkworm Bombyx mori is an economically important insect, as it is the main producer of silk. Fibroin heavy chain (FibH) gene, encoding the core component of silk protein, is specifically and highly expressed in silk gland cells but not in the other cells. Although the silkworm FibH gene has been well studied in transcriptional regulation, its biological functions in the development of silk gland cells remain elusive. In this study, we constructed a CRISPRa system to activate the endogenous transcription of FibH in Bombyx mori embryonic (BmE) cells, and the mRNA expression of FibH was successfully activated. In addition, we found that FibH expression was increased to a maximum at 60 h after transient transfection of sgRNA/dCas9-VPR at a molar ratio of 9:1. The qRT-PCR analysis showed that the expression levels of cellular stress response-related genes were significantly up-regulated along with activated FibH gene. Moreover, the lyso-tracker red and monodansylcadaverine (MDC) staining assays revealed an apparent appearance of autophagy in FibH-activated BmE cells. Therefore, we conclude that the activation of FibH gene leads to up-regulation of cellular stress responses-related genes in BmE cells, which is essential for understanding silk gland development and the fibroin secretion process in B. mori.

In-depth transcriptome unveils the cadmium toxicology and a novel metallothionein in silkworm

Heavy metal pollution has gradually become a major global issue. It is so far reaching in part because heavy metals are absorbed by soil and affect almost all species via ecological cycles. Silkworms (Bombyx mori) are poisoned by heavy metals through a soil-mulberry-silkworm system, which inhibits larval growth and development and leads to a decrease in silk production. In the present study, we performed transcriptome sequencing of larval midgut with cadmium exposure to explore the toxicological mechanism of heavy metal, and found that the following potential pathways may be involved in cadmium infiltration: endocytosis, oxidative phosphorylation, and MAPK signaling. Moreover, we identified a novel metallothionein in silkworm, which is inhibited by cadmium exposure and able to improve heavy metal tolerance in B. mori cell lines and Escherichia coli. We also generated a transgenic silkworm strain overexpressing metallothionein and the result showed that metallothionein observably enhanced larval viability under cadmium exposure. This study used RNA sequencing to reveal a mechanism for cadmium toxicology, and identified and functionally verified BmMT, offering a new potential heavy metal-tolerant silkworm variety.

Deep Sequencing Reveals the Comprehensive CRISPR-Cas9 Editing Spectrum in Bombyx mori

Application of the clustered regularly interspaced short palindromic repeats associated 9 (CRISPR-Cas9) technology has revolutionized biology by greatly enhancing the ability to introduce mutations into DNA for research and prospective therapeutic purposes. However, the understanding of Cas9 editing outcomes is still limited. Previously, it was considered that Cas9 introduces stochastic insertions or deletions (indels) at the target site. In the current study, we performed in vivo multiplex editing, deep sequencing, and comprehensive analysis of its editing outcomes in Bombyx mori (B. mori). A total of 31161 editing events from 9 single-guide RNA (sgRNA) sites in 16 individuals were generated and analyzed, and we found that Cas9 introduces mutations with some regularity rather than via stochastic indels. The editing efficiency varies with sgRNA sequences, individuals, and orientation. Small deletions account for the vast majority of mutated sequences, followed by a small fraction of substitutions and insertions. The most likely mutations are deletions between two microhomologous sequences or single-base deletions at the cleavage site in the absence of microhomologous pairs. Insertions are formed by diverse mechanisms, including direct acquisition of free genomic fragments, duplication of broken ends, replication of adjacent sequences, or random addition of free nucleotides. The above results indicate that the Cas9 editing spectrum is reproducible and predictable. Thus, our findings enable a deeper understanding of Cas9-mediated mutagenesis and better design of genome editing experiments, as well as elucidate the DNA double-strand break repair processes in B. mori.

Genome-wide CRISPR-Cas9 screening in Bombyx mori reveals the toxicological mechanisms of environmental pollutants, fluoride and cadmium

Fluoride and cadmium, two typical environmental pollutants, have been extensively existed in the ecosystem and severely injured various organisms including humans. To explore the toxicological properties and the toxicological mechanism of fluoride and cadmium in silkworm, we perform a CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) -based functional genomic screen, which can directly measure the genetic requirement of genes in response to the pollutants. Our screen identifies 751 NaF-resistance genes, 753 NaF-sensitive genes, 757 CdCl₂-resistance genes, and 725 CdCl₂-sensitive genes. The top-ranked resistant genes are experimentally verified and the results show that their loss conferred resistance to fluoride or cadmium. Functional analysis of the resistant- and sensitive-genes demonstrates enrichment of multiple signaling pathways, among which the MAPK signaling pathway and DNA damage and repair are both required for fluoride- or cadmium-induced cell death, whereas the Toll and Imd signaling pathway and Autophagy are fluoride- or cadmium-specific. Moreover, we confirm that these pathways are truly involved in the toxicological mechanism in both cultured cells and individual tissues. Our results supply potential targets for rescuing the biohazards of fluoride and cadmium in silkworm, and reveal the feasible toxicological mechanism, which highlights the role of functional genomic screens in elucidating the toxicity mechanisms of environmental pollutants.

STING-dependent autophagy suppresses Nosema bombycis infection in silkworms, Bombyx mori

Nosema bombycis is a unicellular spore-forming obligate parasite, related to fungi, and causes infections in economically important animals and are opportunistic human pathogens. However, the mechanisms of host response to N. bombycis remain unclear. STING (stimulator of interferon genes) is an adapter protein involved in the innate immune response to pathogens. In this study, a transgenic gRNA vector containing BmSTING was constructed and microinjected to generate the transgenic line BmSTING^Δ6bp/WT and BmSTING^Δ5bp/WT in silkworms. The expression of BmSTING was significantly reduced in BmSTING^Δ5bp/WT compared to non-transgenic silkworm. The mortality and LC3 (microtubule-associated protein 1 light chain 3) level in BmSTING^Δ6bp/WT and BmSTING^Δ5bp/WT was significantly decreased in the early infection stage of N. bombycis, but the transgenic silkworms died rapidly in the later stage. Furthermore, both BmSTING and LC3 were increased in BmE cell lines after infection with N. bombycis. This study highlights the role of STING-dependent pathways response to microsporidia in silkworm, Bombyx mori.

A deep insight into the transcriptome of midgut and fat body reveals the toxic mechanism of fluoride exposure in silkworm

Fluoride generally exists in the natural environment, and has been reported to induce serious environmental hazard to animals, plants, and even humans via ecological cycle. Silkworm, Bombyx mori, which showed significant growth and reproductivity reduction when exposed to fluoride, has become a model to evaluate the toxicity of fluoride. However, the detailed mechanism underlying fluoride toxicity and corresponding transport proteins remain unclear. In this study, we performed RNA-seq of the larval midgut and fat body with fluoride exposure and normal treatment. Differential analysis showed that there were 4405 differentially expressed genes in fat body and 4430 DEGs in midgut with fluoride stress. By Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, we identified several key pathways involved in the fluoride exposure and poisoning. We focused on the oxidative phosphorylation and MAPK signal pathway. QRT-PCR confirmed that oxidative phosphorylation process was remarkably inhibited by fluoride exposure and resulted in the blocking of ATP synthesis. The MAPK signal pathway was stimulated via phosphorylation signal transduction. Moreover, by protein structure analysis combined with the DEGs, we screen 36 potential membrane proteins which might take part in transporting fluoride. Taken together, the results of our study expanded the underlying mechanisms of fluoride poisoning on silkworm larval growth and development, and implied potential fluoride transport proteins in silkworm.

The novel insight into the outcomes of CRISPR/Cas9 editing intra- and inter-species

The CRISPR/Cas (clustered regularly interspaced short palindromic repeat technology/CRISPR-associated protein) is a widely used and powerful research tool in biosciences and a promising therapeutic agent for treating genetic diseases. Mutations induced by Cas9 are generally considered stochastic and unpredictable, thus hindering its applications where precise genetic alternations are required. Here, through deep sequencing and analysis of genome editing outcomes of multiple sites in four distinct species, we found that Cas9-induced mutations are coincident in mutation types but are significantly different in indel patterns among species. In human and mouse cells, indels were almost evenly distributed at both ends of the cleavage sites. However, the indels mainly appeared at the upstream of cleavage sites in Bombyx mori, while they predominantly occurred downstream of the cleavage sites in the zebrafish Danio rerio. We also found that within a species, indel patterns are sequence dependent, wherein deletions between two adjacent micro-homology sequences were the most frequently observed mutations in the repair spectrum. These results suggested the species differences in DNA repair processes during Cas9-induced gene editing, and the important role of sequence structure at the target site in predicting the gene editing outcome.

[Nursing care of esophagitis dissecans superficialis caused by acute paraquat poisoning]

The clinical data of 13 patients with esophageal dissecans superficials (EDS) induced by paraquat (PQ) in Qilu Hospital from March 2016 to April 2019 were analyzed retrospectively. EDS usually occurs on the 3rd to 9th day after taking poison, and the esophageal mucosa is different in size, color and character, in 10 cases of death, 1 case of pharyngeal pain basically disappeared on the 19th day after EDS onset, but died on the 27th day after taking poison, and 9 cases of death survived 5~19th days after taking poison, the overall cure rate was low; The pharyngeal pain symptoms of 3 surviving patients basically disappeared on day 15, 16 and 17 of EDS, and all patients had no discomfort after eating, and were cured gradually.

A preliminary study: proteomic analysis of exosomes derived from thyroid-stimulating hormone-stimulated HepG2 cells

BACKGROUND

Thyroid-stimulating hormone (TSH) plays an important role in the regulation of lipid metabolism. However, little is known about the role that exosomes play in the process of TSH-induced lipotoxicity in non-alcoholic fatty liver disease (NAFLD). As a preliminary step, the present study set out to investigate alterations in protein expression in exosomes derived from TSH-stimulated HepG2 cells.

METHODS

HepG2 cells were treated with TSH, exosomes were collected, and proteins were identified by mass spectrometry (MS). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis were performed to analyze the identified proteins.

RESULTS

TSH treatment significantly increased exosomal production and changed the exosomal proteomic profile in HepG2 cells. Among the 1728 proteins, 140 identified proteins were upregulated and seven proteins were downregulated. GO analysis and KEGG analysis revealed that these proteins were involved in multiple processes including metabolism, apoptosis, and inflammation.

CONCLUSION

Our preliminary study demonstrated that exosomes derived from TSH-stimulated hepatocytes were increased and showed a specific altered spectrum of proteins, many of which were involved in metabolism, signal transduction, apoptosis, and inflammation. This study offers new insights into the pathogenesis of TSH-induced lipotoxicity in NAFLD.

Display of quintuple glucagon-like peptide 1 (28-36) nonapeptide on Bacillus subtilis spore for oral administration in the treatment of type 2 diabetes

AIMS

To develop an oral delivery system of glucagon-like peptide 1 (GLP-1) (28-36) for treating type-2 diabetes, B.S-GLP-1(28-36), a recombinant Bacillus subtilis spores transformed with a plasmid vector encoding five consecutive GLP-1 (28-36) nonapeptides with an enterokinase site was constructed.

METHODS AND RESULTS

GLP-1(28-36) nonapeptide was successfully expressed on the surface of B. subtilis spores and validated by Western blot and immunofluorescence. The therapeutic effect of oral administration of B.S-GLP-1(28-36) spores was evaluated in type 2 diabetic model mice. The efficacy of recombinant spores was examined for a period of 13 weeks after oral administration in diabetic mice. At the end of the sixth week, diabetic mice with oral administration of BS-GLP-1(28-36) spores showed decreased blood glucose levels from 2·4 × 10^{- 2}  mol l^-1 to 1·7 × 10^{- 2}  mol l^-1 . By the ninth week, the mean fasting blood glucose level in the experimental group was significantly lower than that in the control group 30 min after injection of pyruvate. At the end of the 10th week of oral administration, the blood glucose of the experimental group was significantly lower than that of the control group after intraperitoneal injection of glucose. By the 12th week, fasting blood glucose level and fasting insulin level were measured in all mice, the results showed that the recombinant spores increased the insulin sensitivity of mice.

CONCLUSIONS

The results of pathological observation showed that the recombinant spores also had a certain protective effect on the liver and islets of mice, and the content of GLP-1(28-36) in the pancreas of the experimental group was increased.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this study revealed that GLP-1(28-36) nonapeptides can reduce blood glucose and play an important role in the treatment of type 2 diabetes.