[Lipopolysaccharide stimulates macrophages to secrete exosomes containing miR-155-5p to promote activation and migration of hepatic stellate cells]

OBJECTIVE

To observe the effect of exosomes secreted by lipopolysaccharides (LPS)-stimulated macrophages on hepatic stellate cell activation and migration and explore the underlying molecular mechanism.

METHODS

Human monocyte THP-1 cells were induced to differentiate into macrophages using propylene glycol methyl ether acetic acid (PMA, 100 ng/mL, 24 h) followed by stimulation with LPS, and the culture supernatant of macrophages was collected for extraction of the exosomes by ultracentrifugation. The expression of miR-155-5p in the exosomes was detected using qRT-PCR. A Transwell co-culture system was used to observe the effects of the macrophage-derived exosomes on LX2 cell (a hepatic stellate cell line) proliferation, migration, oxidative stress and the expression of fibrosis biomarkers, which were also observed in LX2 cells transfected with miR-155-5p-mimics or miR-155-5p-inhibitors. Western blotting was used to detect the expressions of SOCS1 and its downstream signal pathway proteins.

RESULTS

Treatment with the exosomes from LPS-stimulated macrophages significantly enhanced the proliferation and migration ability of LX2 cells and increased the levels of oxidative stress and expressions of the fibrosis markers such as type Ⅰ collagen (P < 0.05). The expression of miR-155-5p in the exosomes secreted by macrophages was significantly increased after LPS treatment (P < 0.01). LX2 cells overexpressing miR-155-5p also exhibited significantly enhanced proliferation and migration with increased oxidative stress levels and expression of type Ⅰ collagen (P < 0.05), and interference of miR-155-5p expression produced the opposite effects. Western blotting showed that miR-155-5p overexpression obviously inhibited SOCS1 expression and promoted p-Smad2/3, Smad2/3 and RhoA protein expressions in LX2 cells (P < 0.05).

CONCLUSION

LPS stimulation of the macrophages increases miR-155-5p expression in the exosomes to promote activation and migration and increase oxidative stress and collagen production in hepatic stellate cells.

Immune checkpoint inhibitor-related pneumonitis induced by camrelizumab: a case report and review of literature

Immune checkpoint inhibitors (ICIs) are new agents that are efficacious in a variety of cancers. However, they are associated with immune-related adverse events due to activated immune system. Among them, checkpoint inhibitor pneumonitis (CIP) deserves more special attentions, because diagnosis and therapy are still challengeable. camrelizumab is a programmed cell death 1 (PD-1) inhibitor that was developed by Jiangsu Hengrui Medicine Co. CIP that is induced by camrelizumab was rarely reported. We described a case that a patient developed CIP 12 days later after one dose of camrelizumab. A 60-year-old man with advanced esophageal squamous cell carcinoma received 6 cycles of Tislelizumab/placebo, capecitabine and cisplatin first. Owing to the poor control of the disease, the patient used Nimotuzumab and docetaxel on April 3, 2020 and April 24, 2020, respectively. Later, he obtained the combination of 200 mg of camrelizumab and 140 mg of docetaxel regimen for once on May 14, 2020. After 12 days, he was diagnosed with CIP in Outpatient. Multiple ground glass opacities were revealed in bilateral lungs from routine CT examination. After giving 40 mg of prednisolone orally once a day, his CIP improved. Meanwhile, camrelizumab was not used again. Teaching point: same as other PD-1 inhibitors, camrelizumab can also cause immune-related pneumonitis. Close observation, regular CT examination and timely corticosteroids intervention are essential.

Mechanism and effects of fructose diphosphate on anti-hypoxia fatigue and learning memory ability

This study aims to investigate the mechanisms through which fructose diphosphate (FDP) causes anti-hypoxia and anti-fatigue effects and improves learning and memory. Mice were divided into three groups: low-dose FDP (FDP-L), high-dose FDP (FDP-H), and a control group. Acute toxic hypoxia induced by carbon monoxide, sodium nitrite, and potassium cyanide and acute cerebral ischemic hypoxia were used to investigate the anti-hypoxia ability of FDP. The tests of rod-rotating, mouse tail suspension, and swimming endurance were used to explore the anti-fatigue effects of FDP. The Morris water maze experiment was used to determine the impact of FDP on learning and memory ability. Poisoning-induced hypoxic tests showed that mouse survival time was significantly prolonged in the FDP-L and FDP-H groups compared with the control group (p < 0.05). In the exhaustive swimming test, FDP significantly shortened struggling time and prolonged the time of mass-loaded swimming; the rod-rotating test showed that endurance time was significantly prolonged by using FDP (p < 0.05). FDP significantly decreased lactate and urea nitrogen levels and increased hepatic and muscle glycogen and glucose transporter-4 and Na⁺-K⁺-ATPase (p < 0.05). To conclude, FDP enhances hypoxia tolerance and fatigue resistance and improves learning and memory ability through regulating glucose and energy metabolism.

Dispersal and genetic differentiation of Syntrichia caninervis populations across different desert regions in China

The moss Syntrichia caninervis is widely distributed in cool temperate and cold deserts where environmental pressures create a dependence on asexual reproduction (fragment reproduction). However, when compared to sporophyte-producing mosses, there is a lack of evidence to support the capacity of drought-tolerant mosses that predominantly fragment and produce protonema to disperse over long distances. We used 20 microsatellite loci to study genetic variation and structure in six populations (five natural populations and one population from a regeneration site) in three contrasting and widely separated regions of China. The genetic diversity and expected heterozygosity were lower in populations from the Tengger Desert than in populations from the other regions. Using PCoA, UPGMA and Structure analysis, the genetic grouping divided the three regions into three distinct groups. This may indicate that in regions where S. caninervis reproduces predominantly asexually, propagules are spread mainly by short-distance dispersal. The genetic diversity of the population from the regeneration site in the Tengger Desert was slightly higher than that of the nearby, naturally occurring population, and included some input from the Pamir Plateau almost 2,300 km to the west, suggesting long-distance dispersal of S. caninervis propagules across the region. Predominantly asexually reproducing populations of S. caninervis are mainly dependent on short-distance dispersal. Long-distance dispersal of S. caninervis propagules across the region is difficult. Establishment of populations with dominant asexual reproduction will eventually result in genetic differentiation.

A New System for Whole-atrial Epicardial Mapping

Epicardial mapping system is an important tool in the study and treatment of cardiac arrhythmias. Surgical therapy has been applied to eliminate atrial fibrillation (AF) for almost two decades, but there is still little effect on the treatment of AF in respect that the mechanism of AF is still unknown. Further investigation into the electrophysiological properties in AF is required to develop an appropriate treatment, though radiofrequency ablation has opened the new era of therapies for AF. Nevertheless, the sequential epicardial mapping for whole-atrium will increase the benefit to understand electrical mechanism during AF. The purpose of our research is to detect the electrical activity on the atrial surface and therefore find the optimal technique or ablation procedures to prevent AF. Animal tests were operated on ten dogs in which chronic AF had been induced. In experiment whole-atrial electrodes were located on the atrial surface after the heart had been exposed. Each 20-second sampling data during sinus or atrial fibrillation rhythm were recorded and stored for analysis. Three-dimensional dynamic maps are presented clearly and the activity of sinus or AF rhythm can be seen quite differently. The active isopotential map can display the dynamic electrical conduction of the atria as a movie. This study demonstrates the flexibility of the system in AF research.

Attenuation of neurotoxicity in cortical cultures and hippocampal slices from E2F1 knockout mice

The E2F1 transcription factor modulates neuronal apoptosis induced by staurosporine, DNA damage and beta-amyloid. We demonstrate E2F1 involvement in neuronal death induced by the more physiological oxygen-glucose deprivation (OGD) in mouse cortical cultures and by anoxia in mouse hippocampal slices. E2F1(+/+) and (-/-) cultures were comparable, in that they contained similar neuronal densities, responded with similar increases in intracellular calcium concentration ([Ca(2+)]i) to glutamate receptor agonists, and showed similar NMDA receptor subunit mRNA expression levels for NR1, NR2A and NR2B. Despite these similarities, E2F1(-/-) cultures were significantly less susceptible to neuronal death than E2F1(+/+) cultures 24 and 48 h following 120-180 min of OGD. Furthermore, the absence of E2F1 significantly improved the ability of CA1 neurons in hippocampal slices to recover synaptic transmission following a transient anoxic insult in vitro. These results, along with our finding that E2F1 mRNA levels are significantly increased following OGD, support a role for E2F1 in the modulation of OGD- and anoxia-induced neuronal death. These findings are consistent with studies showing that overexpression of E2F1 in postmitotic neurons causes neuronal degeneration and the absence of E2F1 decreases infarct volume following cerebral ischemia.

Antagonism of a PCP drug discrimination by hallucinogens and related drugs

Drugs such as PCP and MK-801 can cause psychotic reactions in humans by antagonizing NMDA receptors. This action is ultimately toxic to certain cortical neurons and may be one mechanism underlying neurodegenerative diseases, including schizophrenia. It has been reported that hallucinogens such as LSD, DOM, and DOI can block the neurotoxic effects of NMDA antagonists, possibly by activating inhibitory 5-HT2A receptors on GABAergic interneurons that normally inhibit glutamatergic projections to the retrosplenial and cingulate cortexes. The purpose of this experiment was to determine the extent to which similar drugs might also alter the behavioral effects of one NMDA antagonist, PCP. Rats were trained to discriminate this compound (2.5 mg/kg) from saline and were then given a series of antagonist tests. It was found that LSD (0.32 mg/kg) and DOM (4.0 mg/kg) blocked the PCP cue completely; DMT (8.0 mg/kg) and a structural congener of LSD, lisuride (LHM; 0.4 mg/kg), blocked the effects of PCP partially. The 5-HT/DA antagonists spiperone and ritanserin had no effect on the PCP cue. These data suggest that LSD, DOM, and, less effectively, DMT and LHM can block the behavioral as well as the neurotoxic effects of NMDA antagonists most likely through agonist actions at 5-HT2 receptors.

[Effect of ginsenosides on nucleolar organizer region of neuron and sprouting of mossy fibre terminals of hippocampus in rats]

During the production of long-term potentiation (LTP) of the granular cell layer in hippocampal dentate gyrus (DG) and the enhancement of the ability of the memory retention in rats induced by ginsenosides (GSS), the effects of GSS on the number of silver-nucleolar organizer region (Ag-NOR) of neuron and the sprouting of mossy fiber (MF) terminals in hippocampus were studied. Giving GSS for 7 days, the amplitude of population spike (PS) increased by 87.71 +/- 1.91% and the onset and peak latency of PS decreased by 16.60 +/- 1.53%, and 13.5 +/- 0.87% respectively. Meanwhile, GSS could markedly promote the ability of memory retention in rats. In CA3 and DG area, the average number of Ag-NOR of single pyramidal and granular cell in the three GSS groups increased by 66.17 +/- 2.32% and 72.07 +/- 0.93% respectively (P < 0.01). Moreover in CA3, the average of rating scales of MF terminals sprouting in three GSS groups increased 1-3 times as compared with saline groups (P < 0.01). It is suggested that GSS could enhance the transcriptional activity of rDNA and the synthetic ability of protein in hippocampal neuron, as well as promote the sprouting of MF terminals in hippocampus for increasing the efficiency of transmission by hippocampal synapses.

Systematic and random errors in compression testing of trabecular bone

We sought to quantify the systematic and random errors associated with end-artifacts in the platens compression test for trabecular bone. Our hypothesis was that while errors may depend on anatomic site, they do not depend on apparent density and therefore have substantial random components. Trabecular bone specimens were first tested nondestructively using newly developed accurate protocols and then were tested again using the platens compression test. Percentage differences in modulus between the techniques (bovine proximal tibia [n = 18] and humerus [n = 17] and human lumbar spine, [n = 9]) were in the range of 4-86%. These differences did not depend on anatomic site (p = 0.21) and were only weakly dependent on apparent density and specimen aspect ratio (r2 < 0.10). The mean percentage difference in modulus was 32.6%, representing the systematic component of the end-artifact error. Neglecting the minor variations explained by density and specimen size (approximately 10%), an upper bound on the random error from end-artifacts in this experiment was taken as the SD of the modulus difference (+/-18.2%). Based on a synthesis of data taken from this study and from the literature, we concluded that the systematic underestimation error in the platens compression test can be only approximated and is in the range of 20-40%; the substantial random error (+/-12.5%) confounds correction, particularly when the sample size is small. These errors should be considered when interpreting results from the platens test, and more accurate testing techniques should be used when such errors are not acceptable.