Repression of rRNA gene transcription by endothelial SPEN deficiency normalizes tumor vasculature via nucleolar stress

Human cancers induce a chaotic, dysfunctional vasculature that promotes tumor growth and blunts most current therapies; however, the mechanisms underlying the induction of a dysfunctional vasculature have been unclear. Here, we show that split end (SPEN), a transcription repressor, coordinates rRNA synthesis in endothelial cells (ECs) and is required for physiological and tumor angiogenesis. SPEN deficiency attenuated EC proliferation and blunted retinal angiogenesis, which was attributed to p53 activation. Furthermore, SPEN knockdown activated p53 by upregulating noncoding promoter RNA (pRNA), which represses rRNA transcription and triggers p53-mediated nucleolar stress. In human cancer biopsies, a low endothelial SPEN level correlated with extended overall survival. In mice, endothelial SPEN deficiency compromised rRNA expression and repressed tumor growth and metastasis by normalizing tumor vessels, and this was abrogated by p53 haploinsufficiency. rRNA gene transcription is driven by RNA polymerase I (RNPI). We found that CX-5461, an RNPI inhibitor, recapitulated the effect of Spen ablation on tumor vessel normalization and combining CX-5461 with cisplatin substantially improved the efficacy of treating tumors in mice. Together, these results demonstrate that SPEN is required for angiogenesis by repressing pRNA to enable rRNA gene transcription and ribosomal biogenesis and that RNPI represents a target for tumor vessel normalization therapy of cancer.

Oit3, a promising hallmark gene for targeting liver sinusoidal endothelial cells

Liver sinusoidal endothelial cells (LSECs) play a pivotal role in maintaining liver homeostasis and influencing the pathological processes of various liver diseases. However, neither LSEC-specific hallmark genes nor a LSEC promoter-driven Cre mouse line has been introduced before, which largely restricts the study of liver diseases with vascular disorders. To explore LSEC-specific hallmark genes, we compared the top 50 marker genes between liver endothelial cells (ECs) and liver capillary ECs and identified 18 overlapping genes. After excluding globally expressed genes and those with low expression percentages, we narrowed our focus to two final candidates: Oit3 and Dnase1l3. Through single-cell RNA sequencing (scRNA-seq) and analysis of the NCBI database, we confirmed the extrahepatic expression of Dnase1l3. The paired-cell sequencing data further demonstrated that Oit3 was predominantly expressed in the midlobular liver ECs. Subsequently, we constructed inducible Oit3-CreERT2 transgenic mice, which were further crossed with ROSA26-tdTomato mice. Microscopy validated that the established Oit3-CreERT2-tdTomato mice exhibited significant fluorescence in the liver rather than in other organs. The staining analysis confirmed the colocalization of tdTomato and EC markers. Ex-vivo experiments further confirmed that isolated tdTomato+ cells exhibited well-differentiated fenestrae and highly expressed EC markers, confirming their identity as LSECs. Overall, Oit3 is a promising hallmark gene for tracing LSECs. The establishment of Oit3-CreERT2-tdTomato mice provides a valuable model for studying the complexities of LSECs in liver diseases.

Age-related liver endothelial zonation triggers steatohepatitis by inactivating pericentral endothelium-derived C-kit

Aging leads to systemic metabolic disorders, including steatosis. Here we show that liver sinusoidal endothelial cell (LSEC) senescence accelerates liver sinusoid capillarization and promotes steatosis by reprogramming liver endothelial zonation and inactivating pericentral endothelium-derived C-kit, which is a type III receptor tyrosine kinase. Specifically, inhibition of endothelial C-kit triggers cellular senescence, perturbing LSEC homeostasis in male mice. During diet-induced nonalcoholic steatohepatitis (NASH) development, Kit deletion worsens hepatic steatosis and exacerbates NASH-associated fibrosis and inflammation. Mechanistically, C-kit transcriptionally inhibits chemokine (C-X-C motif) receptor (CXCR)4 via CCAAT enhancer-binding protein α (CEBPA). Blocking CXCR4 signaling abolishes LSEC-macrophage-neutrophil cross-talk and leads to the recovery of C-kit-deficient mice with NASH. Of therapeutic relevance, infusing C-kit-expressing LSECs into aged mice or mice with diet-induced NASH counteracts age-associated senescence and steatosis and improves the symptoms of diet-induced NASH by restoring metabolic homeostasis of the pericentral liver endothelium. Our work provides an alternative approach that could be useful for treating aging- and diet-induced NASH.

Myeloid-specific blockade of Notch signaling ameliorates nonalcoholic fatty liver disease in mice

Rationale: Macrophages play a central role in the development and progression of nonalcoholic fatty liver disease (NAFLD). Studies have shown that Notch signaling mediated by transcription factor recombination signal binding protein for immunoglobulin kappa J region (RBP-J), is implicated in macrophage activation and plasticity. Naturally, we asked whether Notch signaling in macrophages plays a role in NAFLD, whether regulating Notch signaling in macrophages could serve as a therapeutic strategy to treat NAFLD. Methods: Immunofluorescence staining was used to detect the changes of macrophage Notch signaling in the livers of human patients with NAFLD and choline deficient amino acid-defined (CDAA) diet-fed mice. Lyz2-Cre RBP-J^flox or wild-type C57BL/6 male mice were fed with CDAA or high fat diet (HFD) to induce experimental steatohepatitis or steatosis, respectively. Liver histology examinations were performed using hematoxylin-eosin (H&E), Oil Red O staining, Sirius red staining and immunohistochemistry staining for F4/80, Col1α1 and αSMA. The expression of inflammatory factors, fibrosis or lipid metabolism associated genes were evaluated by quantitative reverse transcription (qRT)-PCR, Western blot or enzyme-linked immunosorbent assay (ELISA). The mRNA expression of liver samples was profiled by using RNA-seq. A hairpin-type decoy oligodeoxynucleotides (ODNs) for transcription factor RBP-J was loaded into bEnd.3-derived exosomes by electroporating. Mice with experimental NAFLD were treated with exosomes loading RBP-J decoy ODNs via tail vein injection. In vivo distribution of exosomes was analyzed by fluorescence labeling and imaging. Results: The results showed that Notch signaling was activated in hepatic macrophages in human with NAFLD or in CDAA-fed mice. Myeloid-specific RBP-J deficiency decreased the expression of inflammatory factors interleukin-1 beta (IL1β) and tumor necrosis factor alpha (TNFα), attenuated experimental steatohepatitis in mice. Furthermore, we found that Notch blockade attenuated lipid accumulation in hepatocytes by inhibiting the expression of IL1β and TNFα in macrophages in vitro. Meanwhile, we observed that tail vein-injected exosomes were mainly taken up by hepatic macrophages in mice with steatohepatitis. RBP-J decoy ODNs delivered by exosomes could efficiently inhibit Notch signaling in hepatic macrophages in vivo and ameliorate steatohepatitis or steatosis in CDAA or HFD mice, respectively. Conclusions: Combined, macrophage RBP-J promotes the progression of NAFLD at least partially through regulating the expression of pro-inflammatory cytokines IL1β and TNFα. Infusion of exosomes loaded with RBP-J decoy ODNs might be a promising therapy to treat NAFLD.

Notch-triggered maladaptation of liver sinusoidal endothelium aggravates nonalcoholic steatohepatitis through endothelial nitric oxide synthase

BACKGROUND AND AIMS

Although NASH can lead to severe clinical consequences, including cirrhosis and hepatocellular carcinoma, no effective treatment is currently available for this disease. Increasing evidence indicates that LSECs play a critical role in NASH pathogenesis; however, the mechanisms involved in LSEC-mediated NASH remain to be fully elucidated.

APPROACH AND RESULTS

In the current study, we found that LSEC homeostasis was disrupted and LSEC-specific gene profiles were altered in methionine-choline-deficient (MCD) diet-induced NASH mouse models. Importantly, Notch signaling was found to be activated in LSECs of NASH mice. To then investigate the role of endothelial Notch in NASH progression, we generated mouse lines with endothelial-specific Notch intracellular domain (NICD) overexpression or RBP-J knockout to respectively activate or inhibit Notch signaling in endothelial cells. Notably, endothelial-specific overexpression of the NICD accelerated LSEC maladaptation and aggravated NASH, whereas endothelial cell-specific inhibition of Notch signaling restored LSEC homeostasis and improved NASH phenotypes. Furthermore, we demonstrated that endothelial-specific Notch activation exacerbated NASH by inhibiting endothelial nitric oxide synthase (eNOS) transcription, whereas administration of the pharmacological eNOS activator YC-1 alleviated hepatic steatosis and lipid accumulation resulting from Notch activation. Finally, to explore the therapeutic potential of using Notch inhibitors in NASH treatment, we applied two gamma-secretase inhibitors-DAPT and LY3039478-in an MCD diet-induced mouse model of NASH, and found that both inhibitors effectively ameliorated hepatic steatosis, inflammation, and liver fibrosis.

CONCLUSIONS

Endothelial-specific Notch activation triggered LSEC maladaptation and exacerbated NASH phenotypes in an eNOS-dependent manner. Genetic and pharmacological inhibition of Notch signaling effectively restored LSEC homeostasis and ameliorated NASH progression.

[Effectiveness, safety and cost of urinary follicle stimulating hormone in controlled ovarian stimulation in China: multi-center retrospective cohort study of 102 061 in vitro fertilization cycles]

Objective: To explore the effectiveness, safety and cost between urinary follicle stimulating hormone (uFSH) and recombinant follicle stimulating hormone (rFSH) in controlled ovarian stimulation (COS) in China. Methods: Data were collected from 16 reproductive centers in China covering oocytes collection time from May 1, 2015 to June 30, 2018. Eligible patients were over 18 years old, adopting COS with uFSH (uFSH group) or rFSH (rFSH group) as start gonadotropins (Gn), and using in vitro fertilization (IVF) and (or) intracytoplasmic sperm injection for fertilisation, excluding frozen embryo recovery cycle. Generalised estimating equation was used to address the violation of independency assumption between cycles due to multiple IVF cycles for one person and clustering nature of cycles carried out within one center. Controlling variables included age, body mass index, anti-Müllerian hormone level, cause of infertility, ovulation protocol, type of fertilisation, number of embryos transferred, number of days of Gn use. Results: Totally 102 061 cycles met eligibility criteria and were included in the analyses. In terms of effectiveness, after controlling relevant unbalanced baseline characteristics, compared with rFSH group, the high oocyte retrieval (>15 oocytes was considered high retrieval) rate of uFSH group significantly decreased in gonadotropin-releasing hormone agonist protocol (OR=0.642, P<0.01) and in gonadotropin-releasing hormone antagonist protocol (OR=0.556, P=0.001), but the clinical pregnancy rate per transfer cycle and the live birth rate per transfer cycle significantly increased (OR=1.179, OR=1.169, both P<0.01) in both agonist and antagonist protocols. For safety, multiple analysis result demonstrated that in the agonist protocol, compared with rFSH group, the incidence of moderate to severe ovarian hyperstimulation syndrome of uFSH group significantly decreased (OR=0.644, P=0.002). The differences in ectopic pregnancy rate and multiple pregnancy rate between the uFSH and rFSH groups were not significant (P=0.890, P=0.470) in all patients. In terms of cost, compared with rFSH group, the uFSH group had lower total Gn costs for each patient (P<0.01). Conclusion: For patients who underwent COS, uFSH has better safety, and economic profiles over rFSH in China.

Shear stress-induced cellular senescence blunts liver regeneration through Notch-sirtuin 1-P21/P16 axis

BACKGROUND AND AIMS

The mechanisms involved in liver regeneration after partial hepatectomy (pHx) are complicated. Cellular senescence, once linked to aging, plays a pivotal role in wound repair. However, the regulatory effects of cellular senescence on liver regeneration have not been fully elucidated.

APPROACH AND RESULTS

Mice subjected to pHx were analyzed 14 days after surgery. The incomplete remodeling of liver sinusoids affected shear stress-induced endothelial nitric oxide synthase (eNOS) signaling on day 14, resulting in the accumulation of senescent LSECs. Removing macrophages to augment LSEC senescence led to a malfunction of the regenerating liver. A dynamic fluctuation in Notch activity accompanied senescent LSEC accumulation during liver regeneration. Endothelial Notch activation by using Cdh5-CreERT NIC^eCA mice triggered LSEC senescence and senescence-associated secretory phenotype, which disrupted liver regeneration. Blocking the Notch by γ-secretase inhibitor (GSI) diminished senescence and promoted LSEC expansion. Mechanically, Notch-hairy and enhancer of split 1 signaling inhibited sirtuin 1 (Sirt1) transcription by binding to its promoter region. Activation of Sirt1 by SRT1720 neutralized the up-regulation of P53, P21, and P16 caused by Notch activation and eliminated Notch-driven LSEC senescence. Finally, Sirt1 activator promoted liver regeneration by abrogating LSEC senescence and improving sinusoid remodeling.

CONCLUSIONS

Shear stress-induced LSEC senescence driven by Notch interferes with liver regeneration after pHx. Sirt1 inhibition accelerates liver regeneration by abrogating Notch-driven senescence, providing a potential opportunity to target senescent cells and facilitate liver repair after injury.

Notch-Regulated c-Kit-Positive Liver Sinusoidal Endothelial Cells Contribute to Liver Zonation and Regeneration

BACKGROUND & AIMS

Liver sinusoidal endothelial cells (SECs) promote the proliferation of hepatocytes during liver regeneration. However, the specific subset of SECs and its mechanisms during the process remain unclear. In this study, we investigated the potential role of c-kit⁺ SECs, a newly identified subset of SECs in liver regeneration.

METHODS

Partial hepatectomy mice models were established to induce liver regeneration. Hepatic c-kit expression was detected by quantitative reverse-transcription polymerase chain reaction, immunofluorescent staining, and fluorescence-activated cell sorting. VE-cadherin-cyclization recombinase-estrogen receptor (Cdh5-Cre-ERT) Notch intracellular domain and Cdh5-Cre recombination signal binding protein Jκ^floxp mice were introduced to mutate Notch signaling. c-Kit⁺ SECs were isolated by magnetic beads. Single-cell RNA sequencing was performed on isolated SECs. Liver injuries were induced by CCl₄ or quantitative polymerase chain reaction injection.

RESULTS

Hepatic c-kit is expressed predominantly in SECs. Liver resident SECs contribute to the increase of c-kit during partial hepatectomy-induced liver regeneration. Isolated c-kit⁺ SECs promote hepatocyte proliferation in vivo and in vitro by facilitating angiocrine. The distribution of c-kit shows distinct spatial differences that are highly coincident with the liver zonation marker wingless-type MMTV integration site family, member2 (Wnt2). Notch mutation reshapes the c-kit distribution and liver zonation, resulting in altered hepatocyte proliferation. c-Kit⁺ SECs were shown to regulate hepatocyte regeneration through angiocrine in a Wnt2-dependent manner. Activation of the Notch signaling pathway weakens liver regeneration by inhibiting positive regulatory effects of c-kit⁺ SECs on hepatocytes. Furthermore, c-kit⁺ SEC infusion attenuates toxin-induced liver injuries in mice.

CONCLUSIONS

Our results suggest that c-kit⁺ SECs contributes to liver zonation and regeneration through Wnt2 and is regulated by Notch signaling, providing opportunities for novel therapeutic approaches to liver injury in the future. Transcript profiling: GEO (accession number: GSE134037).

Exosome-mediated delivery of RBP-J decoy oligodeoxynucleotides ameliorates hepatic fibrosis in mice

Rationale: Macrophages play multi-dimensional roles in hepatic fibrosis. Studies have implicated Notch signaling mediated by the transcription factor RBP-J in macrophage activation and plasticity. Additionally, we have previously shown that myeloid-specific disruption of RBP-J can ameliorate hepatic fibrosis in mice. Accordingly, we next asked whether blocking Notch signaling in macrophages could serve as a therapeutic strategy to treat hepatic fibrosis. In this study, we used a combination of transcription factor decoy oligodeoxynucleotides (ODNs) and exosomes to test this possibility.

Methods: Hairpin-type decoy oligodeoxynucleotides (ODNs) were designed for the transcription factor RBP-J. The effects of RBP-J decoy ODNs on Notch signaling were evaluated by western blot, quantitative RT-PCR, luciferase reporter assays, and electrophoretic mobility shift assays. ODNs were loaded into HEK293T-derived exosomes by electroporation. A hepatic fibrosis mouse model was established by the intraperitoneal injection of carbon tetrachloride or bile duct ligation. Mice with hepatic fibrosis were administered exosomes loaded with RBP-J decoy ODNs via tail vein injection. The in vivo distribution of exosomes was analyzed by fluorescence labeling and imaging. Liver histology was examined using hematoxylin and eosin, Sirius red, and Masson staining, as well as immunohistochemical staining for Col1α1 and αSMA.

Results: We found that RBP-J decoy ODNs could be efficiently loaded into exosomes and inhibit the activation of Notch signaling. Furthermore, exosomes administered via the tail vein were found to be primarily taken up by hepatic macrophages in mice with liver fibrosis. Importantly, RBP-J decoy ODNs delivered by exosomes could efficiently inhibit Notch signaling in macrophages and ameliorate hepatic fibrosis in mice.

Conclusions: Combined, our data showed that the infusion of exosomes loaded with RBP-J decoy ODNs represents a promising therapeutic strategy for the treatment of hepatic fibrosis.

[Analysis of saliva cotinine and 3'-hydroxynicotinine concentration levels among restaurant workers in six cities of China]

This study was conducted between November to December 2020, consisting of six representative cities, Beijing, Shanghai, Shenzhen (with comprehensive smoke-free legislation), and Changsha, Chongqing, Shenyang (without comprehensive smoke-free legislation), 678 subjects were enrolled eventually, the mean age of the 678 subjects was (35.61±12.91)years old. Subjects from cities with comprehensive smoke-free legislation accounted for 49.71% of the total; male subjects accounted for 19.47%; meanwhile subjects from large, medium, and small restaurants accounted for 13.57% (92), 37.32% (253) and 49.11% (333) respectively. The analysis results indicate that the positive rate of restaurants staff of cotinine and 3'-hydroxynicotinine was lower in cities with comprehensive smoke-free legislation(34.12% vs 68.04%, χ²=78.01, P<0.001; 16.32% vs 41.94%, χ²=53.79, P<0.001), with staff from cities with comprehensive smoke-free legislation have lower concentrations of cotinine and 3'-hydroxynicotinine than their counterparts from cities without comprehensive smoke-free legislation(0.250 ng/ml vs 0.742 ng/ml, P<0.001; 0.250 ng/ml vs 0.250 ng/ml, P<0.001). No statistically significant difference in the concentration of cotinine and 3'-hydroxynicotinine in saliva between staff from restaurants of different sizes was detected (P>0.05).

Notch activation promotes endothelial quiescence by repressing MYC expression via miR-218

After angiogenesis-activated embryonic and early postnatal vascularization, endothelial cells (ECs) in most tissues enter a quiescent state necessary for proper tissue perfusion and EC functions. Notch signaling is essential for maintaining EC quiescence, but the mechanisms of action remain elusive. Here, we show that microRNA-218 (miR-218) is a downstream effector of Notch in quiescent ECs. Notch activation upregulated, while Notch blockade downregulated, miR-218 and its host gene Slit2, likely via transactivation of the Slit2 promoter. Overexpressing miR-218 in human umbilical vein ECs (HUVECs) significantly repressed cell proliferation and sprouting in vitro. Transcriptomics showed that miR-218 overexpression attenuated the MYC proto-oncogene, bHLH transcription factor (MYC, also known as c-myc) signature. MYC overexpression rescued miR-218-mediated proliferation and sprouting defects in HUVECs. MYC was repressed by miR-218 via multiple mechanisms, including reduction of MYC mRNA, repression of MYC translation by targeting heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), and promoting MYC degradation by targeting EYA3. Inhibition of miR-218 partially reversed Notch-induced repression of HUVEC proliferation and sprouting. In vivo, intravitreal injection of miR-218 reduced retinal EC proliferation accompanied by MYC repression, attenuated pathological choroidal neovascularization, and rescued retinal EC hyper-sprouting induced by Notch blockade. In summary, miR-218 mediates the effect of Notch activation of EC quiescence via MYC and is a potential treatment for angiogenesis-related diseases.

Capillarized Liver Sinusoidal Endothelial Cells Undergo Partial Endothelial-Mesenchymal Transition to Actively Deposit Sinusoidal ECM in Liver Fibrosis

Tissue-specific endothelial cells are more than simply a barrier lining capillaries and are proved to be capable of remarkable plasticity to become active collagen matrix-producing myofibroblasts (MFs) in solid organs with fibrosis. Liver sinusoidal endothelial cells (LSECs) also participate in the development of hepatic fibrosis, but the exact roles and underlying mechanism have been poorly understood in addition to capillarization. In this study, we demonstrate, by using single-cell RNA sequencing, lineage tracing, and colocalization analysis, that fibrotic LSECs undergo partial endothelial mesenchymal transition (EndMT) with a subset of LSECs acquiring an MF-like phenotype. These phenotypic changes make LSECs substantial producers of extracellular matrix (ECM) preferentially deposited in liver sinusoids but not septal/portal scars as demonstrated by immunofluorescence in animal models and patients with fibrosis/cirrhosis, likely due to their limited migration. Bioinformatic analysis verifies that LSECs undergo successive phenotypic transitions from capillarization to mesenchymal-like cells in liver fibrosis. Furthermore, blockade of LSEC capillarization by using YC-1, a selective eNOS-sGC activator, effectively attenuates liver damage and fibrogenesis as well as mesenchymal features of LSECs, suggesting that capillarization of LSECs might be upstream to their mesenchymal transition during fibrosis. In conclusion, we report that capillarized LSECs undergo a partial EndMT characterized by increased ECM production without activating cell mobility, leading to perisinusoidal ECM deposition that aggravate liver function and fibrogenesis. Targeting this transitional process may be of great value for antifibrotic treatment of liver fibrosis.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

[Early efficacy of islet transplantation in the treatment of adult advanced diabetes]

Objective: To evaluate the safety and efficacy of islet transplantation for patients with advanced diabetes. Methods: Five cases of islet allotransplantation were performed on 4 adult recipients. The same blood type adult brain-dead pancreas donors were selected and the islets were prepared in GMP laboratory. The prepared islet suspension was slowly injected into the liver of the recipients within 30-60 minutes. The immunosuppressive regimen was a combination of basiliximab, tacrolimus and mycophenolate mofetil and TNF-alpha monoclonal antibody was used to reduce the post-transplant inflammatory response. Insulin was temporarily applied to control blood glucose after surgery, and the dosage of insulin was adjusted to decrease according to the blood glucose level until it was discontinued. Results: A total of 5 islet transplants were performed in 4 patients, including 1 patient who received the second islet transplantations. All operations were succeed and the blood glucose and portal pressure were stable during the operation. Exogenous insulin was continued to keep blood glucose level stable (4-12 mmol/L) after surgery. Four cases (including the one who received two islet transplantation) started to stop using insulin at the third to fourth week, and the insulin dosage of the other case was 74% lower than that before the operation, and no hypoglycemic reaction occurred in all patients after islet transplantation. The C-peptide level in 3 patients reached the normal range, and the level in one patient with type I diabetes (without insulin release) remained at 0.45-0.6 μg/L (0.15-0.2 nmol/L). In addition, one patient showed a rise in blood glucose again and continued to use insulin half a year after insulin discontinuation. Then, he was performed the second islet transplantation which showed good effect and stopped taking insulin in 10 days after surgery. There were 3 cases of liver puncture bleeding after opeation, of which 2 cases were treated with ultrasound radiofrequency ablation to stop bleeding, 1 case stopped spontaneously, and no other complications were found. Conclusions: Islet transplantation is effective in the treatment of advanced diabetes patients with small trauma and high safety, which is worthy of more promotion. Long-term efficacy and maintenance therapy still need further investigation.

[Spectrometric analyses of larotaxel and larotaxel liposomes quantification by high performance liquid chromatography]

OBJECTIVE

Larotaxel is a new chemical structure drug, which has not been marketed worldwide. Accordingly, the standard identification and quantification methods for larotaxel remain unclear. The spectrometric analyses were performed for verifying weight molecular formula, molecular weight and chemical structure of larotaxel. Besides, a quantification method was developed for measuring larotaxel in the liposomes.

METHODS

The molecular formula, molecular weight and chemical structure of larotaxel were studied by using mass spectrometry (MS), infra-red (IR), nuclear magnetic resonance (NMR) and ultraviolet-visible (UV-vis) spectrometric techniques. The absorption wavelength of larotaxel was investigated by UV-vis spectrophotometry full-wavelength scanning. Besides, a quantification method was developed by high performance liquid chromatography (HPLC), and then validated by measuring the encapsulation efficacy of larotaxel liposomes.

RESULTS

The four spectral characteristics of larotaxel were revealed and the corresponding standard spectra were defined. It was confirmed that larotaxel had the structure of tricyclic diterpenoids, with the molecular formula of C45H53NO14, the molecular weight of 831.900 1, and the maximum absorption wavelength of 230 nm. The quantitative method of larotaxel was established by using HPLC with a reversed phase C18 column (5 μm, 250 mm×4.6 mm), a mobile phase of acetonitrile-water (75:25, volume/volume), and a detection wavelength of 230 nm. The validation study exhibited that the established HPLC method was stable, and had a high recovery and precision in the quantitative measurement of larotaxel in liposomes. In addition, a new kind of larotaxel liposomes was also successfully prepared. The particle size of the liposomes was about 105 nm, with an even size distribution. And the encapsulation efficiency of larotaxel in the liposomes was above 80%.

CONCLUSION

The present study offers reference standard spectra of larotaxel, including MS, IR, NMR, and UV-vis, and confirms the molecular formula, molecular weight and chemical structure of larotaxel. Besides, the study develops a rapid HPLC method for quality control of larotaxel liposomes.

[Study on the status of low vision among students of Beijing in 2017]

Objective: The purpose of this study was to describe the status quo and related factors on low vision (LV) among students of Beijing. Methods: All the students in Beijing were included as the subjects of interest, based on the reference of the Chinese National Survey on Students' Constitution and Health. Results: The overall rate of LV among students in Beijing was 58.6% in 2017, with 61.6% in females, higher than 55.9% in males. LV also appeared higher in urban than in rural areas. The rates of LV appeared as 46.8%, 78.0%, 89.0%, 71.0%, in students from primary, middle, high or vocational high schools, respectively. Rates on light, moderate or severe LV were 8.4%, 17.8% and 32.5%, respectively. Conclusions: The overall rate of LV among students in Beijing was considered high. Students in preschool, in 4-6 grades and the 2(nd) grade of middle schools, were at the key stages of developing vision-related problems. Factors as heavy load on homework, lack of outdoor activities and 'limit of vision space' as well as incorrect reading behavior during puberty, need to be of concern.

[National experts consensus on tracheotomy and intubation for burn patients (2018 version)]

Airway edema, stenosis, obstruction and even asphyxia are easy to occur in patients with extensive burn, deep burn of head, face, and neck area, inhalation injuries, etc., which threaten life. Timely tracheotomy and intubation is an important treatment measure, but lack of knowledge and improper handling in some hospitals resulted in airway obstruction. The technique of percutaneous tracheotomy and intubation provides convenience for emergency treatment of critical burns and mass burn. The Chinese Geriatrics Society organized some experts in China to discuss the indications, timing, methods, extubation, and precautions of tracheotomy and intubation for burn patients. The national experts consensus on tracheotomy and intubation for burn patients (2018 version) was written to provide a reference standard for clinical treatment.

[National experts consensus on tracheotomy and intubation for burn patients (2018 version)]

Airway edema, stenosis, obstruction and even asphyxia are easy to occur in patients with extensive burn, deep burn of head, face, and neck area, inhalation injuries, etc., which threaten life. Timely tracheotomy and intubation is an important treatment measure, but lack of knowledge and improper handling in some hospitals resulted in airway obstruction. The technique of percutaneous tracheotomy and intubation provides convenience for emergency treatment of critical burns and mass burn. The Burn and Trauma Branch of Chinese Geriatrics Society organized some experts in China to discuss the indications, timing, methods, extubation, and precautions of tracheotomy and intubation for burn patients. The national experts consensus on tracheotomy and intubation for burn patients (2018 version) was written to provide a reference standard for clinical treatment.

[Efficacy and safety of ombitasvir/paritaprevir/ritonavir and dasabuvir combined with ribavirin in Asian adult patients with chronic HCV genotype 1b infection and compensated cirrhosis]

Objective: To evaluate the efficacy and safety of ombitasvir/paritaprevir/ritonavir (OBV/PTV/r) 25/150/100 mg once daily and dasabuvir (DSV) 250 mg twice daily combined with ribavirin in adult patients of Mainland China with chronic HCV genotype 1b infection and compensated cirrhosis. Methods: An open-label, multicenter, phase 3 clinical trial study was conducted in mainland China, Taiwan, and South Korea. Adult patients with compensated cirrhosis (Metavir score =F4) who were newly diagnosed and treated for hepatitis C virus genotype 1b infection with ombitasvir/paritaprevir/ritonavir and dasabuvir combined with ribavirin for 12 weeks were included. Assessed SVR rate of patients obtained at 12 and 24 weeks after drug withdrawal. Efficacy and safety were evaluated in patients who received at least one time study drugs. Results: A total of 63 patients from mainland China were enrolled, 62 of whom (98.4%) had a baseline Child-Pugh score of 5 points. The overall rate of SVR12 and SVR24 in patients was 100% (95% CI: 94.3% to 100.0%). Most of the adverse events that occurred were mild. The incidence of common (≥10%) adverse events and laboratory abnormalities included elevated total bilirubin (36.5%), weakness (19.0%), elevated unconjugated bilirubin (19.0%) and conjugated bilirubin (17.5%), and anemia (14.3%). Three cases (4.8%) of patients experienced Grade ≥ 3 adverse events that were considered by the investigators to be unrelated to the study drug. None patients had adverse events leading to premature drug withdrawal. Conclusion: Mainland Chinese patients with chronic HCV genotype 1b infection and compensated cirrhosis who were treated with OBV/PTV/r plus DSV combined with RBV for 12 weeks achieved 100 % SVR at 12 and 24 weeks after drug withdrawal. Tolerability and safety were good, and majority of adverse events were mild.

[Association between obesity and DNA methylation among the 7-16 year-old twins]

Objective: On whole-genome scale, we tried to explore the correlation between obesity-related traits and DNA methylation sites, based on discordant monozygotic twin pairs. Methods: A total of 90 pairs of 6-17 year-old twins were recruited in Chaoyang district, Yanqing district and Fangshan district in Beijing in 2016. Information on twins was gathered through a self-designed questionnaire and results: from physical examination, including height, weight and waist circumference of the subjects under study. DNA methylation detection was chosen on the Illumina Human Methylation EPIC BeadChip. R 3.3.1 language was used to read the DNA methylation signal under quality control on samples and probes. Ebayes function of empirical Bayes paired moderated t-test was used to identify the differential methylated CpG sites (DMCs). VarFit function of empirical Bayes paired moderated Levene test was used to identify the differentially variables CpG sits (DVCs) in obese and normal groups. Results According to the obesity discordance criteria, we collected 23 pairs of twins (age range 7 to 16 years), including 12 male pairs. A total of 817 471 qualified CpG loci were included in the genome-wide correlation analysis. According to the significance level of FDR set as <0.05, no positive sites would meet this standard. When DMC CpG site cg05684382, with the smallest P value (1.26E-06) as on chromosome 12, the DVC CpG site cg26188191 with the smallest P value (6.44E-06) appeared in CMIP gene on chromosome 16. Conclusions: In this study, we analyzed the genome-wide DNA methylation and its correlation with obesity traits. After multiple testing corrections, no positive sites were found to have associated with obesity. However, results from the correlation analysis demonstrated sites cg05684382 (chr: 12) and cg26188191 (chr: 16) might have played a role in the development of obesity. This study provides a methodologic reference for the studies on discordance twins related problems.

The Notch ligand delta-like 3 promotes tumor growth and inhibits Notch signaling in lung cancer cells in mice

Although it has been suggested that Dll3, one of the Notch ligands, promotes the proliferation and inhibits the apoptosis of cancer cells, the role of Dll3 in cancers remains unclear. In this study, we found that in the murine Lewis lung carcinoma (LLC) cells, the level of Dll3 mRNA changed upon tumor microenvironment (TME) stimulation, namely, decreased under hypoxia or stimulated with tumor necrosis factor (TNF)-α. Dll3 was also expressed at higher level in human lung carcinoma tissues than in the para-carcinoma tissues. Overexpression of Dll3 in LLC cells promoted cell proliferation and reduced apoptosis in vitro, and enhanced tumor growth when inoculated in vivo in mice. The Dll3-mediated proliferation could be due to increased Akt phosphorylation in LLC cells, because an Akt inhibitor counteracted Dll3-induced proliferation. Moreover, Dll3 overexpression promoted PI3K/Akt signaling through inhibiting Notch signaling.

miR-342-5p Is a Notch Downstream Molecule and Regulates Multiple Angiogenic Pathways Including Notch, Vascular Endothelial Growth Factor and Transforming Growth Factor β Signaling

Background

Endothelial cells (ECs) form blood vessels through angiogenesis that is regulated by coordination of vascular endothelial growth factor (VEGF), Notch, transforming growth factor β, and other signals, but the detailed molecular mechanisms remain unclear.

Methods and Results

Small RNA sequencing initially identified miR‐342‐5p as a novel downstream molecule of Notch signaling in ECs. Reporter assay, quantitative reverse transcription polymerase chain reaction and Western blot analysis indicated that miR‐342‐5p targeted endoglin and modulated transforming growth factor β signaling by repressing SMAD1/5 phosphorylation in ECs. Transfection of miR‐342‐5p inhibited EC proliferation and lumen formation and reduced angiogenesis in vitro and in vivo, as assayed by using a fibrin beads–based sprouting assay, mouse aortic ring culture, and intravitreal injection of miR‐342‐5p agomir in P3 pups. Moreover, miR‐342‐5p promoted the migration of ECs, accompanied by reduced endothelial markers and increased mesenchymal markers, indicative of increased endothelial–mesenchymal transition. Transfection of endoglin at least partially reversed endothelial–mesenchymal transition induced by miR‐342‐5p. The expression of miR‐342‐5p was upregulated by transforming growth factor β, and inhibition of miR‐342‐5p attenuated the inhibitory effects of transforming growth factor β on lumen formation and sprouting by ECs. In addition, VEGF repressed miR‐342‐5p expression, and transfection of miR‐342‐5p repressed VEGFR2 and VEGFR3 expression and VEGF‐triggered Akt phosphorylation in ECs. miR‐342‐5p repressed angiogenesis in a laser‐induced choroidal neovascularization model in mice, highlighting its clinical potential.

Conclusions

miR‐342‐5p acts as a multifunctional angiogenic repressor mediating the effects and interaction among angiogenic pathways.

Pyrrolidine dithiocarbamate restores gastric damages and suppressive autophagy induced by hydrogen peroxide

It is well known that gastric barrier is very important for protecting host from various insults. Simultaneously, autophagy serving as a prominent cytoprotective and survival pathway under oxidative stress conditions is being increasingly recognized. Thus, this study was conducted for investigating the effect of pyrrolidine dithiocarbamate (PDTC) on gastric barrier function and autophagy under oxidative stress induced by intragastric administration of hydrogen peroxide (H2O2). The gastric tight junction proteins [zonula occludens-1 (ZO1), occludin, and claudin1], autophagic proteins [microtubule-associated protein light chain 3I(LC3I), LC3II, and beclin1], and nuclear factor kappa B (NF-κB) signaling pathway (p65 and IκB kinase α/β) were determined by Western blot. The results showed that H2O2 exposure disturbed gastric barrier function with decreased expression of ZO1, occludin, and claudin1, and reduced gastric autophagy with decreased conversion of LC3I into LC3II in mice. However, treatment with PDTC restored these adverse effects evidenced by increased expression of ZO1 and claudin1 and increased conversion of LC3I into LC3II. Meanwhile, H2O2 exposure decreased normal human gastric epithelial mucosa cell line (GES-1) viability in a concentration-dependent way. However, after being exposed to H2O2, GES-1 exhibited autophagic response which was inconsistent with our in vivo results in mice, while PDTC failed to decrease autophagy in GES-1 induced by H2O2. Simultaneously, the beneficial effect of PDTC on gastric damage and autophagy in mice might be independent of inhibition of NF-κB. In conclusion, PDTC treatment restores gastric damages and reduced autophagy induced by H2O2. Therefore, PDTC may serve as a potential adjuvant therapy for gastric damages.

Microwave irradiation is a useful tool for improving isolation of actinomycetes from soil

Actinomycetes are an important source of novel, biologically active compounds. New methods need to be developed for isolating previously unknown actinomycetes from soil. The objective of this experiment was to study microwave irradiation of soil as a means for isolating previously unknown actinomycetes. Soil samples were collected at ten elevations between 800 and 3670 m on Taibai Mountain, Shaanxi Province, China. Moistened soil samples were irradiated at 120 W heating power (2450 MHz) for 3 min using a household microwave oven. Irradiation increased total actinomycete, streptomycete, and antagonistic actinomycete counts on three types of culture media. Irradiation also increased the number of culturable actinomycete isolates. Some actinomycete isolates were culturable only after the soil was irradiated, whereas other isolates could not be cultured after irradiation. Irradiation of soil from elevations > 3000 m increased actinomycete counts significantly but had little effect on the number of culturable actinomycete isolates. In contrast, irradiation of samples from elevations < 3000 m had relatively little effect on actinomycete counts, but significantly increased the number of culturable actinomycete isolates. We used 16S rDNA sequence analysis to identify 14 actinomycete isolates that were only culturable after irradiation. Microwave irradiation of soil was helpful for isolating Streptomyces spp., Nocardia spp., Streptosporangium spp., and Lentzea spp. Slightly more than 90% of the identified actinomycete species were biologically active. In conclusion, microwave irradiation is a useful tool for isolating biologically active actinomycetes from soil.

Preparation and characterization of fouling-resistant composite membranes based on layer-by-layer self-assembly technique

This paper introduces a versatile approach for surface modification of 621-terylene filtration fabric (FF) self-assembled by a dynamic layer-by-layer technique. The hexadecyl trimethyl ammonium bromide (HTAB) and cross-linked polyvinyl alcohol microspheres (PVA-MS) were alternatively deposited on support membrane under a pressure of 0.01 MPa to modify FF. Morphological changes and hydrophilicity of the modified FF were characterized in detail by scanning electron micrograph and water contact angle measurements. Results revealed that PVA-MS could be adsorbed mainly on the surface of FF and water contact angle decreased with the increase of HTAB/PVA-MS bilayer numbers indicating an enhanced hydrophilicity for the modified FF. Backwash experiments of the modified FF exhibited much higher stability of PVA-MS. Protein adsorption experiments were conducted to evaluate the antifouling property of the modified FF. Results indicated that protein adsorption of the membrane surface could be obviously improved by modification, which exhibited superior antifouling property of the modified FF.

LC-MS-MS analysis of 2-pyridylacetic acid, a major metabolite of betahistine: application to a pharmacokinetic study in healthy volunteers

1. A sensitive liquid chromatographic-tandem mas spectrometric assay was developed and validated to determine the major metabolite of betahistine, 2-pyridylacetic acid, in human plasma. 2. The analyte was extracted from plasma samples by liquid-liquid extraction and analysed using liquid chromatography-tandem mass spectrometry with an electrospray ionization interface. The method has a lower limit of quantitation of 1 ng ml(-1) fir a 0.5-ml plasma aliquot. The intra- and interday precision (relative standard deviation), calculated from quality control (QC) samples, was less than 10%. Accuracy as determined from QC samples was within +/-7%. 3. The validated method was successfully applied to a pharmacokinetic study of betahistine in healthy volunteers. After oral administration of a single dose of 24 mg betahistine mesylate to 20 healthy Chinese male volunteers, Cmax was 339.4 ng ml(-1) (range 77.3-776.4 ng ml(-1)). The t(1/2) was 5.2 h (range 2.0(-1)-11.4h). The AUC(0-t) obtained was 1153.5 ng ml(-1) h (range 278.5-3150.8 ng ml(-1)). The disposition of the metabolite exhibited a marked interindividual variation. 4. The plasma concentrations of the parent drug were less than 0.5 ng ml(-1), suggesting that it undergoes almost complete first-pass metabolism. The reported two active metabolites were not detected in the plasma of any volunteer. Although there is no evidence that the major metabolite has pharmacological activity, the clinical importance of 2-pyridylacetic acid in humans should be reinvestigated.

Nucleotide sequences of genome segments S6, S7 and S10 of Dendrolimus punctatus cypovirus 1

The nucleotide sequences of genome segments S6, S7 and S10 of Dendrolimus punctatus cypovirus 1 Hunan I (DpCPV-HN(I)) and DpCPV-HN(I)-Se(3) (DpCPV-HN(I) passed three times in Spodoptera exigua) were determined. Segment S10 was 944 nucleotides in length and encoded a polyhedrin of 248 amino acids (28,439 Da). Only two nucleotide mutations were found between DpCPV-HN(I) S10 and DpCPV-HN(I)-Se3 S10, and the deduced amino acid sequences of the polyhedrin proteins were identical. Segment S7, 1 501 nucleotides, encoded a protein of 448 amino acids ( approximately 50 kDa; p50). Thirty-one nucleotide mutations were found between DpCPV-HN(I) S7 and DpCPV-HN(I)-Se3 S7, but these resulted in only four amino acid changes. DpCPV-HN(I) S6 encoded a protein of 561 amino acids (63,688 Da; p64). The amino acid sequence of p64, had a high leucine content (10%), and contained a leucine zipper motif and one ATP/GTP-binding site motif.