Biological characteristics of microRNAs secreted by exosomes of periodontal ligament stem cells due to mechanical force.

BACKGROUND: Orthodontic tooth movement (OTM) has previously been considered an inflammatory process. However, recent studies suggest that exosomes may play an important role in the cellular microenvironment of OTM. microRNAs (miRNAs) are one of the major constituents of exosomes. This study aims to investigate the biological characteristics of miRNAs secreted by exosomes of periodontal ligament stem cells (PDLSCs) due to mechanical forces. MATERIALS AND METHODS: First, we established a mechanical stress model. The PDLSCs were loaded under different force values and exosomes were extracted after 48 h. High-throughput sequencing of exosomal miRNAs was performed to further evaluate their biological functions and underlying mechanisms. RESULTS: The morphology and functions of exosomes were not significantly different between the loading and non-loading PDLSC groups. The optimal loading time and force were 48 h and 1 g/cm2, respectively. After sequencing, gene ontology (GO) and Kyoto encyclopaedia of genes and genomes (KEGG) pathway and network analyses were performed and 10 differentially expressed miRNAs were identified according to a literature search. These are miR-99a-5p, miR-485-3P, miR-29a-3p,miR-21-5p, miR-146a-5p, miR140-3p, miR-1306-5p, miR-126-5p, miR-125a-5p, and miR-23a-3p. LIMITATIONS: Extracting exosomes needs a large amount of PDLSCs. More functional experiments need to be done to confirm the exact mechanism of exosomal miRNAs of PDLSCs due to mechanical force. CONCLUSIONS: The expression levels of miRNAs secreted by PDLSC-derived exosomes due to mechanical force were very different compared to PDLSC-derived exosomes under nonmechanical stress. The function of many of the identified exosomal miRNAs was found to be related to osteoblasts and osteoclasts. Further validation is required. A functional investigation of these miRNA could provide novel insights into their mechanism.

Effects of microplastics and combined pollution of polystyrene and di-n-octyl phthalate on photosynthesis of cucumber (Cucumis sativus L.).

Photosynthesis provides carbon sources and energy for crop growth and development, and the widespread presence of microplastics and plastic plasticisers in agricultural soils affects crop photosynthesis, but the mechanism of the effect is not clear. This study aims to investigate the effects of different microplastics and plasticizers on cucumber photosynthesis. Using polyvinyl chloride (PVC), polyethylene (PE), polystyrene (PS), and di-n-octyl phthalate (DOP) as representative microplastics and plasticizers, we assessed their impact on cucumber photosynthesis. Our results reveal significant alterations in key parameters: intercellular CO2 concentration (Ci) and transpiration rate (Tr) increased across all treatments, whereas stomatal limit value (Ls) and water use efficiency (WUE) decreased. Notably, PS + DOP treatment led to a significant reduction in the maximum efficiency of photosystem II (Fv/Fm) and ATP accumulation. Furthermore, PE and PS + DOP treatments decreased lycopene and ɛ-carotene synthesis rates, as well as abscisic acid (ABA) accumulation. All treatments inhibited the conversion of ß-carotene into strigolactone (SL) and decreased chlorophyll synthesis rates, with PS + DOP exhibiting the most severe impact. Regarding chlorophyll degradation pathways, PVC and PE treatments reduced chlorophyll decomposition rates, whereas DOP with PS promoted degradation. PE and PS treatments also impaired light energy capture, electron transport, and the structural stability of photosystems I and II, as well as photosynthetic capacity and NADPH and ATP synthesis rates. Our findings underscore the differential impacts of microplastics and plasticizers on cucumber photosynthesis, with PS + DOP having the most detrimental effect. These results shed light on the complex interactions between microplastics and plant physiology, highlighting the urgent need for mitigation strategies in agricultural practices to safeguard crop productivity and environmental sustainability.

Combination of transcriptomics, metabolomics and physiological traits reveals the effects of polystyrene microplastics on photosynthesis, carbon and nitrogen metabolism in cucumber (Cucumis sativus L.).

Although microplastic pollution has been widely studied, the mechanism by which they influence plant photosynthesis and carbon and nitrogen metabolism remains unclear. We aimed to explore the effects of polystyrene microplastics (PS) on photosynthesis and carbon and nitrogen metabolism in cucumber using 5 µm and 0.1 µm PS particles. The PS treatments significantly reduced the stability of cucumber mesophyll cells and photosynthetic parameters and increased the soluble sugar content in cucumber leaves. The 5 µm PS affected the photosynthetic pathway by changing the expression of enzyme genes required for the synthesis of NADPH and ATP, which decreased the photosynthetic capacity in cucumber leaves. However, 0.1 µm PS altered the genes expression of phosphoenolpyruvate carboxykinase (PEPCK) and phosphoenolpyruvate carboxylase (PEPC), which affected the intercellular CO2 concentration and attenuated the negative effects on photosynthetic efficiency. Additionally, PS reduced the expression levels of nitrate/nitrite transporter (NRT) and nitrate reductase (NR), reducing the nitrogen use efficiency in cucumber leaves and mesophyll cells damage through increased accumulation of reduced glutathione (GSH), γ-glutamylcysteine (γ-GC), and citrulline. This study provides a new scientific basis for exploring the effects of microplastics on plant photosynthesis and carbon and nitrogen metabolism.

[Comparison of clear aligners and customized lingual appliance for bimaxillary dentoalveolar protrusion: a retrospective study].

PURPOSE: To compare the treatment effects of clear aligners and customized lingual appliance on treating bimaxillary dentoalveolar protrusion patients with first premolar extractions. METHODS: Fifty-four patients with bimaxillary dentoalveolar protrusion treated in Shanghai Ninth People Hospital were involved in the retrospective study. Twenty-five cases used clear aligners and 29 cases used customized lingual appliance. All of them were treated by extracting 4 first premolars and retracting anterior teeth with strong anchorage. The changes of anterior tooth and soft tissue adduction before and after treatment were compared by lateral cephalometric measurements. SPSS 26.0 software package was used for data analysis. RESULTS: The total course of treatment in the clear aligners group (46.32±7.37 months) was about 10.8 months longer than that in the customized lingual appliance group (35.55±5.90 months) (P＜0.05). There was no significant difference in upper incisor retraction, lower incisor inclination and overjet reduction between the two groups(P＞0.05). There were significant differences in upper lip retraction, lower lip retraction, upper incisor torque reduction, and overbite reduction between the two groups(P＜0.05). Customized lingual appliance group showed a significant improvement of lips retraction and overbite reduction in orthodontic treatment. For the correction of overjet, there was no significant difference between the two groups (P=0.337). The data of U1-OP (the distance between edge of the upper central incisor and the functional occlusal plane) was not in normal distribution, and there was no significant difference between the two groups(P=0.184). CONCLUSIONS: The two techniques can both retract the anterior teeth and lips to improve the profile. However, the customized lingual appliance was more effective in improving the soft tissue profile of patients with bimaxillary dentoalveolar protrusion, with shorter treatment course.

The distribution and impact of polystyrene nanoplastics on cucumber plants.

Microplastic pollution in farmlands has become a source of major concern, but few previous studies have focused on the effect of microplastics on higher plants. In this study, the distribution of polystyrene nanoplastics (PSNPs) of four different particle sizes (100, 300, 500, and 700 nm) was investigated in cucumber plants, and their influence on physiological indexes of the root system and fruit quality was determined. The results showed that PSNPs initially accumulated in the root system before being transported to the aboveground parts of the plant. Finally, they were distributed in the leaves, flowers, and fruits, through the stems. The 300-nm plastic microspheres significantly increased root activity and malondialdehyde (MDA) and proline content of the roots. The results demonstrated that the environmental pressures caused by PSNPs of different particle sizes were different. The amount of soluble protein in cucumber fruits was significantly increased, and the levels of Mg, Ca, and Fe were significantly decreased by PSNPs of different particle sizes. Our findings provide a scientific basis for risk assessment of PSNP exposure in the soil-plant systems.

Composite inclusion complexes containing hyaluronic acid/chitosan nanosystems for dual responsive enrofloxacin release.

In order to overcome treatment difficulty of S. aureus infections, a pH/hyaluronidase dual responsive enrofloxacin-cyclodextrin (ß-CD) inclusion complexes (IC) containing hyaluronic acid/chitosan (HA/CS) self-assemble composite nanosystems covered by poloxamer 188 (F68) was firstly explored for targeted "on-demand" delivery. The FTIR, DSC and PXRD showed that enrofloxacin was embedded into IC and then distributed into F68 coating nanogels formulated by electrostatic interaction between CS and HA. The optimal nanosystems of 118.8 ± 30.7 nm showed excellent stability and responsive release in the acid medium, hyaluronidase containing medium, and LB broth medium where S. aureus present. The nanosystems displayed strong surface adsorption on S. aureus and enhanced activity against S. aureus. It had stronger sustained release than the polymeric nanoparticles formulated by entrapping of IC into F68 and the single HA/CS nanogels. This study provides a promising multi-functionalized nanosystems to overcome the treatment challenge of S. aureus and other bacterial infections.

Physiological response of cucumber (Cucumis sativus L.) leaves to polystyrene nanoplastics pollution.

Microplastics pollution in farmlands has become a major concern. However, few studies have assessed the effects of microplastics on higher plants. In this study, we investigated the influence of polystyrene nanoplastics (PSNPs, 50 mg L-1), with four different particle sizes (100, 300, 500, and 700 nm), on the physiological and biochemical indexes of cucumber leaves. The biomass of cucumber plants significantly decreased after exposure to 300 nm PSNPs. Similarly, the chlorophyll a, chlorophyll b, soluble sugar, carotenoid, and proline content, as well as the fluorescence of cucumber leaves were significantly reduced by 100 nm PSNPs. Malondialdehyde, proline, peroxidase gene expression and enzyme activity, and hydrogen peroxide content significantly increased in cucumber leaves exposed to 700 nm PSNPs. In addition, increasing PSNPs particle size led to decreased relative expression levels and activities of the major antioxidant enzymes superoxide dismutase and catalase, while vitamin C and soluble protein content significantly increased. Overall, our results indicated that PSNPs affect the photosynthetic, antioxidant, and sugar metabolism systems of cucumber leaves, with the latter clearly affecting the total biomass of cucumber plants. The benzene ring resulting from the degradation of PSNPs in cucumber leaves may be the main factor affecting chlorophyll metabolism and sugar metabolism. Our findings provide a scientific basis for the risk assessment of PSNPs exposure in soil-plant systems.

Physiological responses of lettuce (Lactuca sativa L.) to microplastic pollution.

Concerns about the pollution of farmlands by microplastics and the associated toxicology have increased in recent times; however, studies on this topic are scarce. In this study, two kinds of PVC microplastics with different particle sizes (PVC-a with particle sizes from 100 nm to 18 µm, and PVC-b with particle sizes from 18 to 150 µm) and different content levels (0.5%, 1%, and 2%) were used to analyze the effects of PVC microplastics on the physiological characteristics of the lettuce root system and leaves. The results showed that PVC-a and PVC-b had no significant effect on the lettuce root activity. However, 0.5%a and 1%a significantly increased the total length, surface area, volume, and diameter of roots. In terms of leaves, PVC-a and PVC-b had no significant effect on the malondialdehyde content, but 1%a significantly increased the superoxide dismutase activity. Carotenoid synthesis was promoted by PVC-a but inhibited by PVC-b. Furthermore, 1%a could reduce the ability of light energy absorption, dissipation, capture, and electron transfer. The gray correlation analysis indicated that PVC-a correlated to a considerable degree with the indices related to photosynthesis, while PVC-b was significantly correlated with the indices related to root morphology. This study provides insights into the ecotoxicological effect of microplastics on farmland crops and associated ecological risk assessment.