PINK1 in normal human melanocytes: first identification and its effects on H2 O2 -induced oxidative damage

BACKGROUND

Oxidative stress plays an important role in initiating the destruction of melanocytes, which could be one possible mechanism of vitiligo. PINK1 is an outer membrane protein of mitochondria, which protects many cells from oxidative stress through regulating mitochondrial function. However, the role of PINK1 and its effects on oxidative damage in melanocytes have not been elucidated.

AIM

To investigate the expression and effects of PINK1 on oxidative stress in human melanocytes.

METHODS

Quantitative reverse transcription-PCR and western blot analysis were used to analyse the expression of PINK1 in PIG1 melanocyte and gene downregulation models. Levels of cell viability, cell apoptosis and intracellular reactive oxygen species (ROS), mitochondrial morphology, mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (MPTP) opening were measured in PIG1 models transfected with PINK1 small interfering RNA with or without hydrogen peroxide (H₂ O₂ ).

RESULTS

We first observed the expression of PINK1 in human PIG1 melanocytes and found that downregulation of PINK1 made melanocytes more sensitive to oxidative stress induced by H₂ O₂ , with more cell apoptosis and increased intracellular ROS. Meanwhile, downregulation of PINK1 caused morphological changes in mitochondria, decreased the MMP and increased MPTP opening.

CONCLUSIONS

Our study found PINK1 plays an essential role in protecting human melanocytes from oxidative stress.

[The value of 3.0T magnetic resonance -diffusion kurtosis imaging in the differential diagnosis of rectal mucinous adenocarcinoma and common adenocarcinoma]

Objective: To investigate the value of 3.0T MRI diffusion kurtosis imaging (DKI) quantitative histogram parameters in the differential diagnosis of rectal mucinous adenocarcinoma (MC) and common adenocarcinoma (AC). Methods: One hundred and ten patients from Department of Radiology, the Second Affiliated Hospital of Soochow University between September 2015 and September 2019 with complete magnetic resonance imaging (MRI) and DKI results confirmed by surgery and pathology were retrospectively analyzed, including 16 patients in MC group and 94 patients in AC group. Two physicians outlined the region of interest (ROI) on the DKI image with b=1 000 s/mm(2), and obtained quantitative DKI parameters, including the diffusion coefficient (D value) and kurtosis coefficient (K value) corrected for non-Gaussian distribution. The apparent diffusion coefficient (ADC) values of quantitative parameters of diffusion-weighted imaging (DWI) were obtained through image registration, and histogram analysis was performed to obtain the mean value, 25th percentile, 50th percentile, 75th percentile, skewness and kurtosis of the above parameters, respectively. The difference between the quantitative histogram parameter analysis results of the rectal MC group and the AC group was evaluated, and the main indicators and multivariate comprehensive analysis indicators was screened, and the effectiveness of quantitative histogram parameters related to histopathological classification in the differential diagnosis of rectal MC and AC was evaluated. Results: There was no significant differences in gender, age, lesion location, T stage or N stage between MC group and AC group (all P>0.05). The multivariate binary logistic stepwise regression screening showed that D50th percentile and K25th percentile are statistically significant indicators (B values were 2 966.166 and -4.550, respectively; Wals values were 9.000 and 15.720, respectively; and P values were 0.003 and <0.001, respectively). The combined area under the curve of the two indictors was 0.85, but there was no statistically significant difference in pairwise comparison using DeLong method (P>0.05). The results of histogram analysis of quantitative parameters measured by the two physicians were consistent, and the inter-group correlation coefficient ranged from 0.880 to 0.981. Conclusions: The quantitative parameter histogram analysis of the DKI double-index model is helpful for the differentiation of rectal MC and AC, in which the D50th percentile and K25th percentile have differential diagnosis significance, and are superior to the ADC value of the single-index model.

[Establishment of a nucleic acid assay for detection of Echinococcus granulosus based on recombinase-aided isothermal amplification assay]

OBJECTIVE

To establish a nucleic acid assay for detection of Echinococcus granulosus based on recombinase-aided isothermal amplification (RAA) assay.

METHODS

The 12S rRNA gene of E. granulosus was selected as the target gene, and the specific primers and fluorescent probes for RAA assay were designed, screened and synthesized to establish a fluorescent RAA assay for detection of E. granulosus. The sensitivity of the fluorescent RAA assay was evaluated using different copy numbers of target gene sequence-contained recombinant plasmids and various concentrations of E. granulosus genomic DNA as templates, and the specificity of the fluorescent RAA assay was evaluated using the genomic DNA from E. granulosus, E. multilocularis, Schistosoma japonicum, S. mansoni, Ancylostoma duodenale, Clonorchis sinensis, Taenia saginata, Spirometra mansoni and Taenia solium as templates.

RESULTS

A fluorescent RAA assay was successfully established for detection of E. granulosus, which achieved specific amplification of E. granulosus genomic DNA within 20 min at 39 ℃. The lowest detection limit of the fluorescent RAA assay was 10 copies/μL of recombinant plasmids and 0.1 ng/μL E. granulosus genomic DNA, which exhibited a high sensitivity, and the fluorescent RAA assay was all negative for the genomic DNA from E. multilocularis, S. japonicum, S. mansoni, A. duodenale, C. sinensis, T. saginata, Spirometra mansoni and T. solium, which exhibited a high specificity. In addition, this fluorescent RAA assay successfully detected genomic DNA from E. granulosus cysts.

CONCLUSIONS

A rapid, sensitive and specific fluorescent RAA assay is successfully established for nucleic acid detection of E. granulosus.

[Establishment of a recombinase-aided isothermal amplification assay for nucleic acid detection of Angiostrongylus cantonensis]

OBJECTIVE

To establish a recombinase-aided isothermal amplification (RAA) assay for the nucleic acid detection of Angiostrongylus cantonensis.

METHODS

The internal transcribed spacer-1 (ITS1) gene sequence of A. cantonensis was used as the detection target sequence, and the specific primers and probes were designed and synthesized, followed by screening of the primers and probes with the highest specificity, to establish the basic and fluorescent RAA assay for nucleic acid detection of A. cantonensis. The sensitivity of the fluorescent RAA assay was evaluated by using the target gene fragment sequence-contained recombinant plasmids at various copy numbers and the genomic DNA from A. cantonensis as the template DNA samples, and the specificity of the fluorescent RAA assay was evaluated by using the genomic DNA from A. cantonensis, Schistosoma mansoni, Ascaris lumbricoides, Clonorchis sinensis, Echinococcus granulosus and Ancylostoma duodenale, as well as Pomacea canaliculata and Biomphalaria straminea snail tissues as the template DNA samples.

RESULTS

A fluorescent RAA assay was successfully established for nucleic acid detection of A. cantonensis, which achieved real-time amplification of the specific DNA fragment of A. cantonensis within 20 min at 37 ℃. By using the target gene fragment sequence-contained recombinant plasmids at various copy numbers and the genomic DNA from A. cantonensis as the DNA templates, the lowest detection limits of the fluorescent RAA assay were 10 copies/μL of recombinant plasmids and 100 pg/μL of genomic DNA, respectively. The fluorescent RAA assay was negative for detection of the genomic DNA from A. cantonensis, S. mansoni, A. lumbricoides, C. sinensis, E. granulosus, A. duodenale, and P. canaliculata and B. straminea snail tissues.

CONCLUSIONS

A simple, rapid fluorescent RAA assay has been successfully established, which has a high sensitivity and specificity for the nucleic acid detection of A. cantonensis.

[Polarization of human acute monocytic leukemia THP-1 cells-derived macprophages induced by Nippostrongylus brasiliensis proteins in vitro]

OBJECTIVE

To investigate the polarization of human acute monocytic leukemia THP-1 cells-derived macrophages induced by Nippostrongylus brasiliensis proteins in vitro, so as to provide insights into the elucidation of the mechanisms underlying host immune responses to hookworm infections.

METHODS

The in-vitro culture of N. brasiliensis was established and maintained in the laboratory, and the third- (L3) and fifth-stage larvae (L5) were collected under a sterile condition for preparation of L3 and L5 proteins. The in-vitro culture of THP-1 cells was established, stimulated with 500 ng/mL PMA to yield M0 macrophages that were adherent to the plate wall. The LPS + IFN-γ group, IL-4 + IL-13 group, L3 protein group and L5 protein group were given stimulation with 500 ng/mL LPS plus 100 ng/mL IFN-γ, IL-4 and IL-13 (both 100 ng/mL), L3 protein (5 mg/mL) and L5 protein (5 mg/mL), respectively, while the negative control group was given no stimulation. The cell morphology was observed using microscopy, the mRNA expression of M1/M2 macrophages-specific genes was quantified using a quantitative real-time PCR (qPCR) assay, and the surface markers of M1/M2 macrophages were detected using flow cytometry, while the levels of cytokines secreted by M1/M2 macrophages were measured using enzyme-linked immunosorbent assay (ELISA) following stimulations, so as to examine the polarization of THP-1-derived macrophages induced by N. brasiliensis proteins in vitro.

RESULTS

Following stimulation with PMA, THP-1 cells appeared wall-adherent M0 macrophages, and polarized to typical M1 macrophages following stimulation with LPS + IFN-γ, and typical M2 macrophages following stimulation with IL-4 + IL-13, IL-3 protein or L5 protein. There was a significant difference in the proportion of M1 macrophages among the negative control group, the LPS + IFN-γ group, the IL-4 + IL-13 group, the L3 protein group and the L5 protein group (χ² = 3 721.00, P < 0.001), with the highest proportion detected in the LPS + IFN-γ group, and there was also a significant difference in the proportion of M2 macrophages among groups (χ² = 105.43, P < 0.001). There were significant differences among groups in terms of the mRNA expression of CCL2 (F = 191.95, P < 0.001), TNF-α (F = 129.95, P < 0.001), IL-12b (F = 82.89, P < 0.001), PPARγ (F = 11.30, P < 0.001), IL-10 (F = 9.51, P < 0.001) and Mrc1 genes (F = 12.35, P < 0.001). In addition, there were significant differences in the proportion of positive CD86 and CD206 expression among groups (χ² = 24 004.33 and 832.50, P < 0.001). Higher IL-1β and TNF-α levels were measured in the LPS + IFN-γ group than in the IL-4 + IL-13 group, the L3 protein group and the L5 protein group (P < 0.001), and greater TGF-β1 and IL-10 levels were seen in the IL-4 + IL-13 group, the L3 protein group and the L5 protein group than in the negative control group and the LPS + IFN-γ group (P < 0.05).

CONCLUSIONS

Both L3 and L5 proteins of N. brasiliensis may induce the polarization of THP-1-derived macrophages to M2 type in vitro.

High expression level of interleukin-1β is correlated with poor prognosis and PD-1 expression in patients with lung adenocarcinoma

PURPOSE

Cytokines are vital pro-inflammatory factors and involved in tumor immune infiltration, and immune infiltration is closely related to PD-1/PD-L1 blockades immunotherapy. This study aims to explore the associations between cytokines and prognosis and also PD-1/PD-L1 expression in early lung adenocarcinoma, which is seldom reported.

METHODS

324 early lung adenocarcinoma patients with prior surgical resection were included and the associations between overall survival time and clinical factors and also cytokines including IL-1β, IL-6 and TNF-α were analyzed by multivariate cox regression and Kaplan-Meier curve (log-rank test). Resected tumor samples were randomly obtained to detect the PD-1/PD-L1 expression by immunohistochemistry, and Chi square test was used for relations between cytokines and PD-1/PD-L1 expression.

RESULTS

In this study group, 26.2% patients showed a high level of IL-1β and patients with high IL-1β level showed 19 months shortened mOS than those with normal IL-1 β expression (mOS: 24.00, 95%CI 11.98-36.02 vs 43.00, 95% CI 37.37-48.63, p = 0.017). Among detected samples, the positive rate of PD-1 was 25.0% (13/52), and the positive rate of PD-L1 was 37.3% (19/52). The positive rate of PD-1 was 36.1% higher in high-IL-1 β-level group as compared to normal-IL-1β-level group (50.0% vs 13.9%, p = 0.012). No significant association was found between IL-1 β and PD-L1 expression.

CONCLUSION

High expression level of IL-1β was correlated with poor prognosis and higher positive rate of PD-1 expression, which gave us insights into biomarkers of survival prediction and immunotherapy in lung adenocarcinoma. Further studies were still needed.

[Investigation on the risk of of Anisakis infection among high - risk populations along the coastal areas of Jiangsu Province]

OBJECTIVE

To investigate the risk of Anisakis infections among high-risk populations along the coastal areas of Jiangsu Province, so as to develop the strategy for the prevention and control of anisakiasis in the province.

METHODS

Three counties along the coastal areas of Jiangsu Province were selected as the study sites in 2018, including Rudong County in Nantong City, Haizhou District in Lianyungang City and Dongtai City in Yancheng City. The knowledge, attitude and practice (KAP) of anisakiasis prevention and control, and the prevalence of serum specific IgG antibody against Anisakis were investigated among high-risk populations among these three study sites, including fishermen, fish seller and people who liked eating fresh and live marine fish. Factors affecting the prevalence of the specific IgG antibody against Anisakis were identified using a multiple logistic regression model. In addition, Anisakis larvae infections were detected in fresh and live marine fish samples collected from local markets, and the prevalence and intensity of Anisakis infections were estimated.

RESULTS

A total of 625 high-risk populations were investigated, including 349 men (55.8%). Only 13.0% of the subjects heard about anisakiasis, and a low awareness rate of anisakiasis prevention and control knowledge was seen among these three types of high-risk populations. There were 21.6% of the subjects eating raw or half-cooked marine fish, 5.8% eating undercooked marine fish, 3.2% presenting vomiting, nausea and diarrhea after eating marine fish, 5.1% developing systemic allergic symptoms, and 65.6% using the same chopping board for raw and cooked food. The sero-prevalence of the anti-Anisakis IgG antibody was 7.0% among the study subjects. Multiple logistic regression analysis identified education level [OR = 0.687, 95% CI (0.478, 0.987)] and development of systemic allergic symptoms [OR = 4.641, 95% CI(1.411, 15.268)]as factors affecting the positive anti-Anisakis IgG antibody among the study subjects. Among 494 fresh and live marine fish detected, the prevalence and intensity of Anisakis larvae infection was 64.0% and 8.1 larvae per fish, with high prevalence seen in Trichiurus haumela and Pneumatophorus japonicas.

CONCLUSIONS

The awareness of anisakiasis prevention and control knowledge is low among the high-risk populations living along the coastal areas of Jiangsu Province, and there are high-risk behaviors, such as eating raw or half-cooked food, using the same chopping board for raw and cooked food. In addition, the prevalence of Anisakis infections is high in the marine fish in these areas. Therefore, the health education and health promotion for anisakiasis prevention and control should be intensified.

Pre-selecting markers based on fixation index scores improved the power of genomic evaluations in a combined Yorkshire pig population

Combining different swine populations in genomic prediction can be an important tool, leading to an increased accuracy of genomic prediction using single nucleotide polymorphism (SNP) chip data compared with within-population genomic. However, the expected higher accuracy of multi-population genomic prediction has not been realized. This may be due to an inconsistent linkage disequilibrium (LD) between SNPs and quantitative trait loci (QTL) across populations, and the weak genetic relationships across populations. In this study, we determined the impact of different genomic relationship matrices, SNP density and pre-selected variants on prediction accuracy using a combined Yorkshire pig population. Our objective was to provide useful strategies for improving the accuracy of genomic prediction within a combined population. Results showed that the accuracy of genomic best linear unbiased prediction (GBLUP) using imputed whole-genome sequencing (WGS) data in the combined population was always higher than that within populations. Furthermore, the use of imputed WGS data always resulted in a higher accuracy of GBLUP than the use of 80K chip data for the combined population. Additionally, the accuracy of GBLUP with a non-linear genomic relationship matrix was markedly increased (0.87% to 15.17% for 80K chip data, and 0.43% to 4.01% for imputed WGS data) compared with that obtained with a linear genomic relationship matrix, except for the prediction of XD population in the combined population using imputed WGS data. More importantly, the application of pre-selected variants based on fixation index (Fst) scores improved the accuracy of multi-population genomic prediction, especially for 80K chip data. For BLUP|GA (BLUP approach given the genetic architecture), the use of a linear method with an appropriate weight to build a weight-relatedness matrix led to a higher prediction accuracy compared with the use of only pre-selected SNPs for genomic evaluations, especially for the total number of piglets born. However, for the non-linear method, BLUP|GA showed only a small increase or even a decrease in prediction accuracy compared with the use of only pre-selected SNPs. Overall, the best genomic evaluation strategy for reproduction-related traits for a combined population was found to be GBLUP performed with a non-linear genomic relationship matrix using variants pre-selected from the 80K chip data based on Fst scores.

Strengthening the maternal and child health system in remote and low-income areas through multilevel governmental collaboration: a case study from Nujiang Prefecture in China

OBJECTIVE

The aim of the study was to assess the effects of the maternal and child health (MCH) system strengthening through multilevel governmental collaboration in Nujiang Prefecture, China.

STUDY DESIGN

A case study design was applied.

METHODS

Guided by the logical framework of the Nujiang MCH Comprehensive Intervention Project, national, provincial, and prefecture government sectors jointly implemented comprehensive health system strengthening (HSS) interventions in Nujiang Prefecture. In this case study, we conducted the end point surveys (November 2015 and January 2016) with 33 local MCH facilities. We also interviewed 35 MCH providers, government officials, leaders of MCH facilities, and project specialists. The thematic framework method was used to analyze the interview data, and descriptive analysis was performed to analyze the survey data.

RESULTS

The three levels of governmental collaboration contributed to increased government investment in the local MCH system and ensured the successful implementation of the project. Participatory training methods and appropriate HSS interventions tailored to the local context were crucial to improve MCH providers' knowledge and skills, with the proportion of qualified MCH providers increasing from 70% in 2011 to 96% in 2015. Owing to this increase in knowledge and the increase in needed equipment, more MCH hospitals could provide inpatient obstetric services, and more town health clinics were capable of providing basic MCH services. The development of a reimbursement policy tailored to the local context promoted in-hospital delivery. At the conclusion of the project, percentages of antenatal care, in-hospital delivery, and newborn screening increased by 20.71%, 18.12%, and 278.62%, respectively. Growth monitoring coverage for children younger than three years remained stable at around 90%. However, the MCH system was negatively impacted by the workforce shortage. Those shortages were caused by a lack of positive recruitment and retention and incentive policies.

CONCLUSIONS

Implementation of comprehensive HSS interventions through multilevel governmental collaboration improves the MCH system in remote and low-income areas.

The Nab experiment: A precision measurement of unpolarized neutron beta decay

Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, λ = gA/gV, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter a with a precision of δa/a = 10−3 and the Fierz interference term b to δb = 3 × 10−3 in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio λ with a precision of δλ/λ = 0.03% that will allow an evaluation of Vud and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.

Final results for the neutron -asymmetry parameter A0 from the UCNA experiment

The UCNA experiment was designed to measure the neutron β-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A0.

[Establishment and preliminary evaluation of recombinase aided isothermal amplification (RAA) assay for specific nucleic acid detection of Clonorchis sinensis]

OBJECTIVE

To establish a recombinase aided isothermal amplification (RAA) assay for detection of Clonorchis sinensis.

METHODS

The 18S ribosomal RNA (18S rRNA) sequence of C. sinensis was used as the target sequence, and specific primers and probes were designed, synthesized and screened to establish a rapid fluorescent RAA assay for the detection of C. sinensis. Then, the sensitivity of the fluorescent RAA assay was evaluated using the recombinant plasmids containing various copy numbers of DNA fragments and C. sinensis genomic DNA at various concentrations, and the specificity of the fluorescent RAA as say was evaluated using the genomic DNA of Ascaris lumbricoides, Echinococcus granulosus, Schistosoma japonicum, Ancylostoma duodenale and S. mansoni as templates. DNA samples were extracted from the feces containing C. sinensis eggs and freshwater fish containing metacercaria for the fluorescent RAA assay, and the performance for detection of C. sinensis-infected samples was preliminarily assessed in the field.

RESULTS

A fluorescent RAA assay for detection of C. sinensis was successfully established, which was feasible for specific amplification of C. sinensis genomic DNA at 39 °C within 20 min. The lowest detection limit was 10 copies/μL if the recombinant plasmid containing various copy numbers of DNA fragments was used as a template, and the lowest detection limit was 3 pg/μL if the C. sinensis genomic DNA at various concentrations served as a template. All detections were negative if the genomic DNA of A. lumbricoides, E. granulosus, S. japonicum, A. duodenale, and S. mansoni was used as templates. In addition, the fluorescent RAA assay showed a high performance for the detection of C. sinensis-infected samples in the field, which successfully detected C. sinensis-infected human and rat fecal samples and Pseudorasbora parva samples.

CONCLUSIONS

A fluorescent RAA assay is successfully established, which is simple, rapid, sensitivity and specific for detection of C. sinensis.

VEGFR2 and VEGF-C Suppresses the Epithelial-Mesenchymal Transition Via YAP in Retinal Pigment Epithelial Cells

BACKGROUND

Whereas retinal pigment epithelial (RPE) cells are known to secrete VEGF-A and VEGFR2, the functions of the autocrine VEGF signaling remain unclear. Meanwhile, anti-VEGF therapies have been applied routinely to treat ocular vascular diseases.

OBJECTIVE

The aim of this study was to determine the functions of the VEGF signaling in RPE cells and evaluate the consequences of its interruption.

METHODS

The genes involved in the VEGF and Hippo signal pathways were knocked down with siRNAs in both ARPE-19 cell line and human primary RPE cells via transient transfection whereas overexpression of VEGFR2 was mediated via adenovirus transduction. Expression of the epithelial-mesenchymal transition (EMT) markers and the downstream genes of YAP were determined by real-time PCR and Western Blot analysis. Immunofluorescence staining was utilized to determine gene expression in tissue and mouse samples.

RESULTS

Knockdown of VEGFR2 results in epithelial-mesenchymal transition in vitro and in vivo. Overexpression of VEGFR2 suppresses TGF β-mediated EMT in RPE cells. Loss of VEGF-C rather than VEGF-A induces EMT. Mechanistically, the VEGFR2 ablation-induced EMT in RPE cells is mediated by activation of YAP, an effector of the Hippo pathway. Finally, the immunohistochemical analysis of VEGFR2 and YAP in human proliferative vitreoretinopathy (PVR) membranes indicates a tendency of an inverse correlation between VEGFR2-positive and YAP-positive cells.

CONCLUSIONS

Our results disclose unexpected novel roles of VEGFR2 and VEGF-C in the process of EMT of RPE cells and in the Hippo pathway. The data shown here demonstrated that VEGFR2 and VEGF-C are important to maintain the normal physiological state of RPE cells.