MicroRNA-448/EPHA7 axis regulates cell proliferation, invasion and migration via regulation of PI3K/AKT signaling pathway and epithelial-to-mesenchymal transition in non-small cell lung cancer

OBJECTIVE

Non-small cell lung cancer (NSCLC) is a primary subtype of lung cancers which has a high morbidity and poor prognosis. Emerging evidence has demonstrated that aberrantly expressed microRNAs (miRNAs) were implicated in the regulatory functions of multiple processes during tumorigenesis. In the current study, we explored the functional roles and underlying mechanisms of miR-448 in NSCLC.

PATIENTS AND METHODS

Quantitative real-time polymerase chain reaction assays were conducted to measure miR-448 expressions in 51 pairs of NSCLC tissues and corresponding normal tissues. Moreover, the relationship between miR-448 expressions and clinicopathological characteristics of NSCLC patients was also determined. We then performed transwell assays to explore the functions of miR-448 in NSCLC cell invasion and migration. As we had identified EPHA7 as a functional target of miR-448 in NSCLC cells, the clinical significance of EPHA7 in NSCLC patients was further investigated. Finally, we detected the influence of miR-448 on tumor growth rate and tumor size of NSCLC using tumor xenografts.

RESULTS

Underexpressed miR-448 was identified in NSCLC, and low miR-448 expression was confirmed to be associated with the poor prognosis and adverse clinicopathologic features of NSCLC patients. Moreover, functional assays demonstrated that miR-448 overexpression suppressed NSCLC cell proliferation, invasion and migration. EPHA7 was identified as a direct target of miR-448. Additionally, miR-448 restoration suppressed in vivo NSCLC cell growth. Finally, our studies also indicated that miR-448 exerted anti-NSCLC functions via regulating PI3K/AKT signaling pathway and EMT.

CONCLUSIONS

These results showed that miR-448/EPHA7 axis maybe one of the useful diagnostic and prognostic biomarkers for NSCLC patients.

Histology-based profile of inflammatory mediators in experimentally induced pulpitis in a rat model: screening for possible biomarkers

Aim

To profile molecular changes in lipopolysaccharide (LPS)‐induced experimental pulpitis in a rat model and explore the feasibility of a molecular‐based diagnostic strategy for pulpitis.

Methodology

Seventy‐three maxillary incisors of Sprague‐Dawley rats were used to establish pulpitis models with LPS. Inflammatory grading was performed in four equal sections of the pulp divided from the injured site to the root apex. An antibody array was used to compare the expression of 67 molecules between control pulp and inflamed pulp 12 and 72 h after LPS application. The levels of differentially expressed molecules in the control and inflamed pulp (collected at 3, 6, 9, 12, 24 and 72 h after LPS treatment) were examined via ELISA, and correlations between inflammatory scores and molecule expression were assessed. The molecule distributions in the pulp were investigated by immunofluorescence staining. Data were analysed with paired t‐test, one‐way anova, Kruskal–Wallis tests, and Spearman’s and Pearson’s correlations with significance set at P < 0.05.

Results

Polymorphonuclear neutrophils were observed in the injured site 3 h after LPS stimulation. Inflammatory infiltration peaked at 12 h and was limited to the injured site with osteodentine deposition at 72 h. Thirteen molecules were significantly differentially expressed between the control and LPS‐injured pulp. ELISA validated that tissue inhibitor of metalloproteinase‐1 (TIMP‐1) expression dramatically peaked at 12 h (compared with other time points, P < 0.05) and returned to baseline at 72 h. The TIMP‐1 concentration was strongly correlated with inflammation severity in the apical three‐quarters of the pulp, and the strongest correlation was found in the lower‐middle quarter (r = 0.786, P < 0.001). Immunofluorescence staining revealed that in the apical three‐quarters of the pulp, TIMP‐1 expression was significantly higher in the 12 h group than in the control and 3, 6, 24 and 72 h groups (P < 0.01).

Conclusion

This study provides a molecular profile of LPS‐induced pulpitis in a rat model. TIMP‐1 had a strong positive correlation with the severity of dental pulp inflammation, verifying the feasibility of applying biomarkers to identify specific pathological conditions in pulpitis.

Overexpression of miRNA-433-5p protects acute spinal cord injury through activating MAPK1

OBJECTIVE

The aim of this study was to clarify the role of microRNA-433-5p (miRNA-433-5p) in influencing pathological lesions following acute spinal cord injury (SCI) by targeting mitogen-activated protein kinase 1 (MAPK1).

PATIENTS AND METHODS

SCI model was successfully established in mice by performing hitting injury procedures. Serum levels of miRNA-433-5p and MAPK1 in SCI patients and mice were determined. Grip strengths of both forelimbs in SCI mice and controls were determined. Dual-Luciferase reporter gene assay was applied to verify the binding relation between miRNA-433-5p and MAPK1. After overexpression of miRNA-433-5p and MAPK1 in vivo, the grip strength changes in SCI mice were assessed. Furthermore, the protein level of inflammatory factor iNOS in 293T cells influenced by miRNA-433-5p and MAPK1 was detected by Western blot.

RESULTS

MiRNA-433-5p was significantly downregulated in the serum of SCI patients and mice, whereas MAPK1 was up-regulated. Grip strengths of SCI mice were significantly lower than those of controls at different postoperative time points. However, this could be markedly reversed by the in vivo overexpression of miRNA-433-5p. Western blot indicated that the protein level of iNOS was remarkably downregulated in 293T cells overexpressing miRNA-433-5p. MAPK1 was confirmed as the target of miRNA-433-5p, whose expression level was negatively regulated by miRNA-433-5p. Importantly, MAPK1 partially reversed the protective role of miRNA-433-5p in grip strength of SCI mice and inflammatory response at post-SCI.

CONCLUSIONS

Overexpression of miRNA-433-5p protects SCI-induced motor dysfunction and inflammatory response by targeting MAPK1.

MiR-223-3p inhibits inflammation and pyroptosis in monosodium urate-induced rats and fibroblast-like synoviocytes by targeting NLRP3

Down-regulated miR-223-3p was found in rheumatoid arthritis. This study aimed to further explore the level and role of miR-223-3p in gout arthritis (GA). After monosodium urate (MSU)-induced GA rat and fibroblast-like synoviocytes (FLSs) models were established, the rat paw volume and gait score were documented and the FLSs were transfected with miR-223-3p mimic/inhibitor or NLR family pyrin domain containing 3 (NLRP3) over-expression plasmids. The MiR-223-3p target was found through bioinformatics and the dual-luciferase reporter. The rat joint pathological damage was observed by hematoxylin and eosin staining. The levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α and articular elastase in rats were detected by enzyme-linked immunosorbent assay (ELISA). The viability and pyroptosis of FLSs were detected by methyl thiazolyl tetrazolium (MTT) and flow cytometry. The expressions of miR-223-3p, NLRP3, cleaved caspase-1, IL-1β, apoptosis-associated speck-like protein (AS) and cleaved N-terminal gasdermin D (GSDMD) in FLSs or rat synovial tissues were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, Western blot or immunohistochemistry analysis. MSU increased the paw volume, gait score, inflammation in synovial tissues and increased the levels of IL-1β, TNF-α and articular elastase in rats. MSU decreased the viability and increased the pyroptosis of FLSs, up-regulated the expression of NLRP3, ASC, cleaved caspase-1, cleaved N-terminal GSDM, and IL-1β, and down-regulated miR-223-3p expression in synovial tissues of rat joints and FLSs. MiR-223-3p mimic reversed the effect of MSU on lowering cell viability, increasing pyroptosis in FLSs, while miR-223-3p inhibitor further enhanced the effect of MSU on FLSs. NLRP3 was a target of miR-223-3p. Also, NLRP3 over-expression reversed the effects of miR-223-3p on MSU-induced FLSs. MiR-223-3p inhibited pyroptosis in MSU-induced rats and FLSs by targeting NLRP3.

Properties of Heavy Secondary Fluorine Cosmic Rays: Results from the Alpha Magnetic Spectrometer

Precise knowledge of the charge and rigidity dependence of the secondary cosmic ray fluxes and the secondary-to-primary flux ratios is essential in the understanding of cosmic ray propagation. We report the properties of heavy secondary cosmic ray fluorine F in the rigidity R range 2.15 GV to 2.9 TV based on 0.29 million events collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The fluorine spectrum deviates from a single power law above 200 GV. The heavier secondary-to-primary F/Si flux ratio rigidity dependence is distinctly different from the lighter B/O (or B/C) rigidity dependence. In particular, above 10 GV, the F/Si/B/O ratio can be described by a power law R^{δ} with δ=0.052±0.007. This shows that the propagation properties of heavy cosmic rays, from F to Si, are different from those of light cosmic rays, from He to O, and that the secondary cosmic rays have two classes.

Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62×10^{6} iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. Above 80.5 GV the rigidity dependence of the cosmic ray Fe flux is identical to the rigidity dependence of the primary cosmic ray He, C, and O fluxes, with the Fe/O flux ratio being constant at 0.155±0.006. This shows that unexpectedly Fe and He, C, and O belong to the same class of primary cosmic rays which is different from the primary cosmic rays Ne, Mg, and Si class.

Cross-Kingdom Cell-to-Cell Interactions in Cariogenic Biofilm Initiation

Candida albicans is known to form polymicrobial biofilms with various Streptococcus spp., including mitis and mutans group streptococci. Streptococcus gordonii (mitis group) has been shown to bind avidly to C. albicans hyphae via direct cell-to-cell interaction, while the cariogenic pathogen Streptococcus mutans (mutans group) interacts with the fungal cells via extracellular glucans. However, the biophysical properties of these cross-kingdom interactions at the single-cell level during the early stage of biofilm formation remain understudied. Here, we examined the binding forces between S. mutans (or S. gordonii) and C. albicans in the presence and absence of in situ glucans on the fungal surface using single-cell atomic force microscopy and their influence on biofilm initiation and subsequent development under cariogenic conditions. The data show that S. gordonii binding force to the C. albicans surface is significantly higher than that ofS. mutans to the fungal surface (~2-fold). However, S. mutans binding forces are dramatically enhanced when the C. albicans cell surface is locally coated with extracellular glucans (~6-fold vs. uncoated C. albicans), which vastly exceeds the forces between S. gordonii andC. albicans. The enhanced binding affinity of S. mutans to glucan-coated C. albicans resulted in a larger structure during early biofilm initiation compared to S. gordonii-C. albicans biofilms. Ultimately, this resulted in S. mutans dominance composition in the 3-species biofilm model under cariogenic conditions. This study provides a novel biophysical aspect of Candida-streptococcal interaction whereby extracellular glucans may selectively favor S. mutans binding interactions with C. albicans during cariogenic biofilm development.

microRNA-1205 promotes cell growth by targeting APC2 in lung adenocarcinoma

OBJECTIVE

An increasing amount of evidence indicates that microRNAs (miRNAs) can be potential diagnostic and prognostic markers for various cancers. In this study, a novel miRNA, miR-1205, was identified in lung adenocarcinoma (LUAD).

PATIENTS AND METHODS

First, the expression of miR-1205 in tissues was determined and verified to be correlated with the prognosis of patients. Overexpression and knockdown in LUAD cells were chosen to evaluate the effect of miR-1205 on cell growth in vitro. Luciferase assays, Western blot and rescue assays were performed to screen and confirm potential targets of miR-1205.

RESULTS

We demonstrated that miR-1205 was down-regulated in the tissues of LUAD, and that miR-1205 may be a predictor of overall survival of LUAD. The overexpression of miR-1205 promoted cell proliferation and colony formation. Our results indicated that miR-1205 targeted APC2 directly, serving as a vital part in accelerating LUAD cell proliferation.

CONCLUSIONS

We showed that miR-1205 could promote LUAD cell growth by targeting APC2 protein expression and provided further proof of miR-1205 as a potential non-invasive biomarker and therapeutic target for LUAD.

Reconstructing the Perceived Faces from Brain Signals without Large Number of Training Samples. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020;2020:1108-1111. [PMID: 33018180 DOI: 10.1109/embc44109.2020.9176684]

Reconstructing the perceived faces from brain signals has become a promising work recently. However, the reconstruction accuracies rely on a large number of brain signals collected for training a stable reconstruction model, which is really time consuming, and greatly limits its application. In our current study, we develop a new framework that can efficiently perform high-quality face reconstruction with only a small number of brain signals as training samples. The framework consists of three mathematical models: principle component analysis (PCA), linear regression (LR) and conditional generative adversarial network (cGAN). We conducted a functional Magnetic Resonance Imaging (fMRI) experiment in which two subjects' brain signals were collected to test the efficiency of our proposed method. Results show that we can achieve state-of-the-art reconstruction performance from brain signals with a very limited number of fMRI training samples.

FRI0385 MUSCLE FUNCTION AND QUALITY BUT NOT MASS PROTECT AGAINST MORE SEVERE KNEE PAIN TRAJECTORIES

Background:

Evidence suggests that periarticular muscles have a role in the pathogenesis of pain, but results have not been consistent. We recently reported that pain population is heterogenous and consists of different subgroups of which the causes and mechanisms differ.

Objectives:

To examine the association of muscle mass, leg strength, knee extensor strength, low-limb muscle quality with knee pain trajectories.

Methods:

Data on 975 participants from a population-based older adult cohort study were utilised. Dual-energy X-ray absorptiometry was used to assess muscle/fat mass. Leg strength in both legs and dominant knee extensor strength were measured. Low-limb muscle quality was calculated (i.e. leg strength divided by lower-limb muscle mass). The Western Ontario and McMaster Universities Osteoarthritis Index pain questionnaire was used to measure knee pain at each time-point. Radiographic knee osteoarthritis (ROA) was assessed by X-ray. Group-based trajectory modelling was applied to identify pain trajectories. Multi-nominal logistic regression was used for the analyses.

Results:

A total of 975 participants [Mean±SD: age 62.2±7.4 years, body mass index (BMI) 27.8±4.6 kg/m2and 51% of females] were included in the analysis. Three distinct pain trajectories were identified: ‘Minimal pain’ (53%), ‘Mild pain’ (34%) and ‘Moderate pain’ (13%). In multivariable analysis, both greater total and low-limb muscle mass were associated with an increased risk of ‘Mild pain’ [total muscle mass: relative risk (RR): 1.51 per SD increase, 95%CI: 1.14−1.98; low-limb muscle mass RR: 1.33 per SD increase, 95%CI: 1.07−1.66] and ‘Moderate pain’ [total muscle mass: RR: 2.57 per SD increase, 95%CI: 1.70−3.89); low-limb muscle mass RR: 2.03 per SD increase, 95%CI: 1.47−3.80)] compared to the ‘Minimal pain’ trajectory group. After further adjustment for fat mass, these associations disappeared. Total muscle mass percentage was associated with a reduced risk of being worse pain trajectories. In relative to the ‘Minimal pain’ trajectory group, leg strength, knee extensor strength and quality were associated with a reduced risk of being in more severe pain trajectories after adjustment for covariates (RR=0.56 to 0.71 per SD increase, all P<0.05). Similar results were observed in those with ROA.

Conclusion:

Muscle percentage, strength and quality, but not muscle mass itself are associated with a reduced risk of being more severe pain trajectories, suggesting that improving muscle composition, muscle function and power are of more clinically relevance to preventing the development and maintenance of worse pain trajectories.

Disclosure of Interests:

None declared

Properties of Neon, Magnesium, and Silicon Primary Cosmic Rays Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary cosmic rays, neon (Ne), magnesium (Mg), and silicon (Si), measured in the rigidity range 2.15 GV to 3.0 TV with 1.8×10^{6}  Ne, 2.2×10^{6}  Mg, and 1.6×10^{6}  Si nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The Ne and Mg spectra have identical rigidity dependence above 3.65 GV. The three spectra have identical rigidity dependence above 86.5 GV, deviate from a single power law above 200 GV, and harden in an identical way. Unexpectedly, above 86.5 GV the rigidity dependence of primary cosmic rays Ne, Mg, and Si spectra is different from the rigidity dependence of primary cosmic rays He, C, and O. This shows that the Ne, Mg, and Si and He, C, and O are two different classes of primary cosmic rays.

Deep learning radiomic nomogram can predict the number of lymph node metastasis in locally advanced gastric cancer: an international multicenter study

BACKGROUND

Preoperative evaluation of the number of lymph node metastasis (LNM) is the basis of individual treatment of locally advanced gastric cancer (LAGC). However, the routinely used preoperative determination method is not accurate enough.

PATIENTS AND METHODS

We enrolled 730 LAGC patients from five centers in China and one center in Italy, and divided them into one primary cohort, three external validation cohorts, and one international validation cohort. A deep learning radiomic nomogram (DLRN) was built based on the images from multiphase computed tomography (CT) for preoperatively determining the number of LNM in LAGC. We comprehensively tested the DLRN and compared it with three state-of-the-art methods. Moreover, we investigated the value of the DLRN in survival analysis.

RESULTS

The DLRN showed good discrimination of the number of LNM on all cohorts [overall C-indexes (95% confidence interval): 0.821 (0.785-0.858) in the primary cohort, 0.797 (0.771-0.823) in the external validation cohorts, and 0.822 (0.756-0.887) in the international validation cohort]. The nomogram performed significantly better than the routinely used clinical N stages, tumor size, and clinical model (P < 0.05). Besides, DLRN was significantly associated with the overall survival of LAGC patients (n = 271).

CONCLUSION

A deep learning-based radiomic nomogram had good predictive value for LNM in LAGC. In staging-oriented treatment of gastric cancer, this preoperative nomogram could provide baseline information for individual treatment of LAGC.

Diagnostic value of ultrasound elastography for differentiation of benign and malignant axillary lymph nodes: a meta-analysis

AIM

To investigate the diagnostic value of ultrasound elastography (UE) for benign and malignant axillary lymph nodes.

MATERIALS AND METHODS

A literature search was conducted from PubMed, Cochrane EMBASE, and Medline. Fourteen studies including 1,186 patients with 1,411 lymph nodes were enrolled. Overall, diagnostic descriptive statistics included pooled sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) with corresponding 95% confidence intervals (95% CIs) were generated by random effect model. Subgroup analyses were performed in (real-time elastography [RTE] versus shear wave elastography [SWE]) and (conventional ultrasound versus combination of traditional ultrasound and elastography). Meta-regression was used to explore potential sources of heterogeneity.

RESULTS

The overall pooled sensitivity, specificity, and AUC of UE was 0.79 (95% CI: 0.71-0.86), 0.90 (95% CI: 0.83-0.95), and 0.91 (95% CI: 0.88-0.93), respectively. In the subgroup analysis of the two UE techniques, the pooled sensitivity, specificity, and AUC of SWE was higher than that of RTE (sensitivity: 0.82>0.77; specificity: 0.91>0.89; AUC: 0.94>0.89). The pooled diagnostic value of ultrasound combined with UE were significantly improving compared with traditional ultrasound (sensitivity: 0.87>0.82, specificity: 0.83>0.78, and AUC: 0.91>0.87). No independent heterogeneous factor was found in meta-regression.

CONCLUSION

The results indicate that UE was an effective technique for identifying malignant axillary lymph nodes due to its high diagnostic efficiency, which can provide useful information for surgical procedure selection.

Release of extracellular vesicle miR-494-3p by ARPE-19 cells with impaired mitochondria

BACKGROUND

Mitochondrial function in retinal pigmented epithelial (RPE) cells and extracellular vesicle (EV) formation/release are related through the lysosomal and exocytotic pathways that process and eliminate intracellular material, including mitochondrial fragments. We propose that RPE cells with impaired mitochondria will release EVs containing mitochondrial miRNAs that reflect the diminished capacity of mitochondria within these cells.

METHODS

We screened ARPE-19 cells for miRNAs that localize to the mitochondria, exhibit biological activity, and are present in EVs released by both untreated cells and cells treated with rotenone to induce mitochondrial injury. EVs were characterized by vesicle size, size distribution, presence of EV biomarkers: CD81, CD63, and syntenin-1, miRNA cargo, and number concentration of EVs released per cell.

RESULTS

We found that miR-494-3p was enriched in ARPE-19 mitochondria. Knockdown of miR-494-3p in ARPE-19 cells decreased ATP production and mitochondrial membrane potential in a dose-dependent manner, and decreased basal oxygen consumption rate and maximal respiratory capacity. Increased number of EVs released per cell and elevated levels of miR-494-3p in EVs released from ARPE-19 cells treated with rotenone were also measured.

CONCLUSIONS

ARPE-19 mitochondrial function is regulated by miR-494-3p. Elevated levels of miR-494-3p in EVs released by ARPE-19 cells indicate diminished capacity of the mitochondria within these cells.

GENERAL SIGNIFICANCE

EV miR-494-3p is a potential biomarker for RPE mitochondrial dysfunction, which plays a central role in non-neovascular age-related macular degeneration, and may be a diagnostic biomarker for monitoring the spread of degeneration to neighboring RPE cells in the retina.

Development and validation of an individualized nomogram to identify occult peritoneal metastasis in patients with advanced gastric cancer

Background

Occult peritoneal metastasis (PM) in advanced gastric cancer (AGC) patients is highly possible to be missed on computed tomography (CT) images. Patients with occult PMs are subject to late detection or even improper surgical treatment. We therefore aimed to develop a radiomic nomogram to preoperatively identify occult PMs in AGC patients.

Patients and methods

A total of 554 AGC patients from 4 centers were divided into 1 training, 1 internal validation, and 2 external validation cohorts. All patients’ PM status was firstly diagnosed as negative by CT, but later confirmed by laparoscopy (PM-positive n = 122, PM-negative n = 432). Radiomic signatures reflecting phenotypes of the primary tumor (RS1) and peritoneum region (RS2) were built as predictors of PM from 266 quantitative image features. Individualized nomograms of PM status incorporating RS1, RS2, or clinical factors were developed and evaluated regarding prediction ability.

Results

RS1, RS2, and Lauren type were significant predictors of occult PM (all P < 0.05). A nomogram of these three factors demonstrated better diagnostic accuracy than the model with RS1, RS2, or clinical factors alone (all net reclassification improvement P < 0.05). The area under curve yielded was 0.958 [95% confidence interval (CI) 0.923–0.993], 0.941 (95% CI 0.904–0.977), 0.928 (95% CI 0.886–0.971), and 0.920 (95% CI 0.862–0.978) for the training, internal, and two external validation cohorts, respectively. Stratification analysis showed that this nomogram had potential generalization ability.

Conclusion

CT phenotypes of both primary tumor and nearby peritoneum are significantly associated with occult PM status. A nomogram of these CT phenotypes and Lauren type has an excellent prediction ability of occult PM, and may have significant clinical implications on early detection of occult PM for AGC.

Porphyromonas gingivalis Induces Insulin Resistance by Increasing BCAA Levels in Mice

Insulin resistance is one of the critical pathogeneses of type 2 diabetes mellitus (T2DM). Elevated levels of plasma branched-chain amino acids (BCAAs) are associated with insulin resistance. Recent studies have demonstrated the role of Porphyromonas gingivalis in the development of insulin resistance. However, the mechanisms by which P. gingivalis induces insulin resistance are still unclear. The purpose of this study was to investigate whether P. gingivalis induces insulin resistance through BCAA biosynthesis. We established a murine model of periodontitis by infecting mice with P. gingivalis. Alveolar bone loss, insulin sensitivity, and the plasma level of BCAAs were measured. A P. gingivalis BCAA aminotransferase-deficient strain (∆bcat) was constructed, and its kinetic growth, biofilm formation, and in vivo colonization were compared with its wild-type strain. Alveolar bone loss, insulin sensitivity, and the plasma level of BCAAs of the mice infected with either wild-type strain or ∆bcat strain were further measured. We found that periodontal infection with P. gingivalis significantly upregulated the plasma level of BCAAs and aggravated the high-fat diet (HFD)-induced insulin resistance. Bcat deletion did not alter the growth, biofilm formation, and in vivo colonization of P. gingivalis. More important, the ∆bcat strain was unable to upregulate the plasma level of BCAAs and induce insulin resistance in HFD-fed mice. These findings suggest that the BCAA biosynthesis of P. gingivalis plays a critical role in the development of insulin resistance in the HFD-fed mice. The BCAA biosynthesis pathways may provide a potential target for the disruption of linkage between periodontitis and T2DM.

Improving timing performance of double-ended readout in TOF-PET detectors

Scintillation crystals of 20mm length or longer are needed for clinical time-of-flight positron emission tomography (TOF-PET) to ensure effective detection efficiency for gamma photons. However, the use of long crystals would deteriorate the key performance of TOF-PET detectors, time and spatial resolution, because of the variations in the travel times of the photons in crystals and the effects of parallax errors. In this work, we studied double-ended readout TOF-PET detectors based on coupling a long scintillation crystal to SiPMs at both ends for correcting the depth-dependent effects to improve the coincidence time resolution (CTR). In particular, we focused our attention to analyze timing performance using different correction methods, including trigger times of the individual photodetectors at both ends of the crystal, the simple average of the trigger times, and the weighted average based on the inverse variances of the depth-dependent corrected trigger times. For a 3 mm × 3 mm × 25mm unpolished lutetium fine silicate (LFS) crystal with double-ended readout and practical head-on irradiation, a CTR of 246ps FWHM can be achieved using depth-dependent timing-correction and weighted average time method compared to 280ps FWHM using the conventional simple average time method and 393ps FWHM using the conventional single-ended readout. The results show that the depth-dependent timing-correction and weighted average time method in double-ended readout can effectively correct for the trigger time variations in TOF-PET detector utilizing long unpolished crystals, resulting in an improvement in the CTR of as much as 37% compared to single-ended readout.

MiR-143-3p regulates early cartilage differentiation of BMSCs and promotes cartilage damage repair through targeting BMPR2

OBJECTIVE

The aim of this study was to explore the role of microRNA-143-3p (miR-143-3p) in cartilage injury, and to investigate the possible underlying mechanism.

MATERIALS AND METHODS

A chondrogenic differentiation cell model was established in bone marrow mesenchymal stem cells (BMSCs). The mRNA expression levels of runt-related transcription factor 2 (RUNX2), miR-143-3p and bone morphogenetic protein 2 (BMPR2) in BMSCs were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) after 0 d, 5 d and 10 d, respectively. Mesenchymal stem cells (MSCs) were transfected with miR-143-3p mimics and its control in accordance with the liposome method. Alcian blue colorimetric assay was used to evaluate proteoglycan deposition of MSCs. Meanwhile, qRT-PCR and Western blot were performed to analyze the expression levels of ACAN and COL2A1. Luciferase reporter gene assay was applied to verify the binding status of miR-143-3p and BMPR2 3'UTR. Also, proteoglycan deposition and the expression of ACAN and COL2A1 were detected after simultaneous transfection of miR-143-3p mimics and BMPR2 overexpression plasmid.

RESULTS

0 d, 5 d and 10 d after inducing cartilage differentiation, the mRNA expression levels of RUNX2 and BMPR2 were markedly increased. However, the expression level of miR-143-3p was significantly decreased with the prolongation of induction period. After transfection with miR-143-3p mimics, the level of miR-143-3p in MSCs was remarkably increased. Alcian blue colorimetric assay and staining assay showed that the deposition of proteoglycans in the mimics group was significantly lower than that of the control group. Meanwhile, after overexpressing miR-143-3p, the levels of cartilage differentiation marker proteins including ACAN and COL2A1 were remarkably reduced. Luciferase report gene assay indicated that miR-143-3p could negatively regulate BMPR2 by binding to its 3'UTR. In addition, overexpression of BMPR2 could strikingly reverse the above effects of overexpressed miR-143-3p.

CONCLUSIONS

During chondrogenic differentiation, the level of miR-143-3p was decreased. Moreover, miR-143-3p could regulate the differentiation process by targeting BMPR2 in BMSCs.

Downregulation of HOTTIP regulates insulin secretion and cell cycle in islet β cells via inhibiting MEK/ERK pathway

OBJECTIVE

To investigate the effect of long non-coding RNA (lncRNA) HOTTIP on islet β cells and its underlying mechanism.

MATERIALS AND METHODS

The expressions of HOTTIP in different organs of db/db mice and C57BL/6J mice were detected by quantitative Real-time polymerase chain reaction (qRT-PCR). Effects of HOTTIP on the proliferation, insulin secretion and apoptosis of islet β cells transfected with lentivirus were detected by cell counting kit-8 (CCK-8) assay, enzyme-linked immunosorbent assay (ELISA) and flow cytometry, respectively. We also assessed the protein expressions of key genes in MEK/ERK pathway by using Western blot.

RESULTS

HOTTIP was upregulated in normal islet tissues of C57BL/6J mice but downregulated in islet tissues of diabetic mice. Inhibition of HOTTIP attenuated insulin secretion and reduced expressions of Pdx1 and MafA. Downregulation of HOTTIP also inhibited cell proliferation and reduced expressions of CyclinDl, CyclinD2, CyclinE1 and CyclinE2. Moreover, islet β cells were arrested in G0/G1 phase after HOTTIP knockdown. Our data showed that the biological function of HOTTIP in regulating insulin secretion and cell cycle in islet β cells might be related to the MEK/ERK pathway.

CONCLUSIONS

Downregulation of HOTTIP inhibits insulin secretion and cell cycle in islet β cells via MEK/ERK pathway.

Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of ^{3}He and ^{4}He fluxes are presented. The measurements are based on 100 million ^{4}He nuclei in the rigidity range from 2.1 to 21 GV and 18 million ^{3}He from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the ^{3}He and ^{4}He fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the ^{3}He/^{4}He flux ratio is measured for the first time. Below 4 GV, the ^{3}He/^{4}He flux ratio was found to have a significant long-term time dependence. Above 4 GV, the ^{3}He/^{4}He flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law ∝R^{Δ} with Δ=-0.294±0.004. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.