Inverse Regulation of C-C Chemokine Receptor 3 Oligomerization by Downstream Proteins Indicates Biased Signal Transduction Pathways.

Oligomerization is one of the important mechanisms for G protein-coupled receptors (GPCRs) to modulate their activity in signal transduction. However, details of how and why the oligomerization of GPCRs regulates their functions under physiological conditions remain largely unknown. Here, using single-molecule photobleaching technology, we show that chemokine ligand 5 (CCL5) and chemokine ligand 8 (CCL8) are similar to the previously reported chemokine ligand 11 (CCL11) and chemokine ligand 24 (CCL24), which can regulate the oligomerization of chemokine receptor 3 (CCR3). Our results further demonstrate that downstream proteins, ß-arrestin 2 and Gi protein complex, on the CCR3 signal transduction pathway, can inversely regulate the oligomeric states of CCR3 induced by its binding ligands. This unexpected discovery suggests complex relationships between the oligomeric behaviors of CCR3 and the components of ligands-CCR3-downstream proteins, reflecting the potentially functional impact of the oligomerization on the multiple activation pathways of GPCR, such as biased activation.

CeO2NP priming enhances the seed vigor of alfalfa (Medicago sativa) under salt stress.

Soil salinization is a common environmental problem that seriously threatens crop yield and food security, especially through its impact on seed germination. Nanoparticle priming, an emerging seed treatment method, is receiving increasing attention in improving crop yield and stress resistance. This study used alfalfa seeds as materials to explore the potential benefits of cerium oxide nanoparticle (CeO2NP) priming to promote seed germination and improve salt tolerance. CeO2NPs at concentrations up to 500 mg/L were able to significantly alleviate salt stress in alfalfa seeds (200 mM), with 50 mg/L of CeO2NP having the best effect, significantly (P< 0.05) increasing germination potential (from 4.0% to 51.3%), germination rate (from 10.0% to 62.7%), root length (from 8.3 cm to 23.1 cm), and seedling length (from 9.8 cm to 13.7 cm). Priming treatment significantly (P< 0.05) increased seed water absorption by removing seed hardness and also reducing abscisic acid and jasmonic acid contents to relieve seed dormancy. CeO2NP priming increased α-amylase activity and osmoregulatory substance level, decreased reactive oxygen species and malonaldehyde contents and relative conductivity, and increased catalase enzyme activity. Seed priming regulated carotenoid, zeatin, and plant hormone signal transduction pathways, among other metabolic pathways, while CeO2NP priming additionally promoted the enrichment of α-linolenic acid and diterpenoid hormone metabolic pathways under salt stress. In addition, CeO2NPs enhanced α-amylase activity (by 6.55%) in vitro. The optimal tested concentration (50 mg/L) of CeO2NPs was able to improve the seed vigor, enhance the activity of α-amylase, regulate the osmotic level and endogenous hormone levels, and improve the salt tolerance of alfalfa seeds. This study demonstrates the efficacy of a simple seed treatment strategy that can improve crop stress resistance, which is of great importance for reducing agricultural costs and promoting sustainable agricultural development.

Application Effects of SBAR Communication Mode in ICU Nursing Physical Restraint Shift.

Context: Correct and effective handovers of patients' information during shift changes can ensure patients' safety and can help an incoming shift of nurses to continuously monitor patients' psychological problems and avoid unnecessary physical restraints. Development of a standard procedure for handover of patients who have been physically restrained has important clinical significance related to the smooth continuation of nursing work and assurance of the quality of care. Objective: The study intended to investigate the clinical effects of the situation-background-assessment-recommendation (SBAR) communication mode on the quality of the information passed during shift changes about patients in intensive care units (ICUs) who had been physically restrained and to compare it to the clinical effects obtained using traditional methods of communication. Design: The study was a retrospective analysis of the process used by nurses who were passing patient's information during shift changes when caring for patients who had been physically restrained. Setting: The study took place in an ICU at the Second Hospital of Hebei Medical University in Shijiazhuang, Hebei, China. Participants: Participants were 21 nurses caring for 239 ICU patients under physical restraint at the Second Hospital. Intervention: Of the 239 patients, 118 had been hospitalized between March 1 and March 15, 2018 and were assigned to the control group, and 121 had been hospitalized between June 1 and June 15, 2018 and were assigned to the intervention group. An ICU Physical Restraint Handover Order was established according to the SBAR communication mode. The intervention group used the SBAR communication mode and the control group used the hospital's routine communication mode for the physical restraint of a patient during a nursing shift. Outcome Measures: The study measured the differences between the groups in the nurses' passing rates based on standards for the use of physical restraints, the quality of handover of information during shift changes about patients under physical restraint, the quality of the documentation written by nurses about the physical restraint, and the nurses' satisfaction with the handover of information during a shift change. Results: Among the patient, 112 in the intervention group (92.56%) and 92 in the control group (77.97%) were qualified for physical restraint. A statistically significant difference existed between the two groups in the passing rate for the use of physical restraints (P = .001). The quality score for the handovers during shift changes of patients under physical restraint in the intervention group was 95.46 ± 2.50 and for the control group was 91.08 ± 3.57, with the difference being statistically significant (P = .030). The quality score for the nursing documentation for the intervention group, at 97.21 ± 1.49, was higher than that of the control group, at 90.78 ± 3.42, and the difference was statistically significant (P < .001). The nurses' satisfaction score for the intervention group, at 98.14 ± 1.01 was higher than that of the control group, at 92.57 ± 1.86, and the difference was statistically significant (P = .006). Conclusions: The use of the SBAR communication mode to improve the information passed to nurses about patients under physical restraint during a shift change can improve the quality of the physical restraint and nurses' satisfaction and has a better clinical-application effect than the traditional methods used during shift changes.

Oligomerization-Enhanced Receptor-Ligand Binding Revealed by Dual-Color Simultaneous Tracking on Living Cell Membranes.

GPCR oligomerization plays a critical role in cellular signaling, yet the stoichiometry of the interactions between oligomers and binding ligands in living cells remains a longstanding challenge. Here, by developing a dual-color simultaneous tracking system based on a total internal reflection fluorescence microscope (TIRFM), the CCR5-CCL5 interactions are visualized and quantitatively assessed in real time. Results show that each oligomeric state of CCR5 could bind with CCL5 but with different binding affinities; CCR5 dimers have a 3.5-fold higher binding affinity than the monomers. The dimerization may cause an asymmetric conformational change which makes the first binding pocket have a 3.5-fold higher binding affinity and the second have only a half compared with the monomeric CCR5. This study is the first example to directly scrutinize the CCR5-CCL5 interactions at the single-molecule level on living cell membranes and will offer great potential for the interaction stoichiometry study of diverse surface proteins.

miR-34a regulates HDAC1 expression to affect the proliferation and apoptosis of hepatocellular carcinoma.

miR-34a is an important molecule that can inhibit the tumor growth. This study aimed to investigate the functional role of miR-34a in hepatocellular carcinoma (HCC) and explore the interaction between miR-34a and histone deacetylase 1 (HDAC1). RT-qPCR was employed to detect the mRNA expression of miR-34a and HDAC1 in 60 HCC tissues. Results showed miR-34a expression in HCC tissues was significantly lower than in normal tissues (P<0.05), but HDAC1 expression in HCC tissues was markedly higher than in normal tissues (P<0.05). In addition, miR-34a expression was negatively related to HDAC1 expression. miR-34a mimic was transfected into HCC cell lines (HepB3 and HepG2). CCK8 assay, colony formation assay and flow cytometry showed miR-34a over-expression could inhibit the proliferation of HCC cells and induce their apoptosis. Western blotting indicated miR-34a over-expression down-regulated the expression of Bcl-2, procaspase-3, procaspase-9 and c-Myc, but up-regulate p21 expression. Bioinformatics analysis indicated HDAC1 was a target gene of miR-34a. Dual Luciferase Reporter Gene Assay and retrieval assay showed miR-34a could act at the 3'UTR of HDAC1 gene to regulate its expression. Thus, miR-34a may inhibit the proliferation of HCC cells and induce their apoptosis via regulating HDAC1 expression. Our findings provide evidence for the diagnosis and therapeutic target of HCC.