Low-Protein Diet Inhibits the Synovial Tissue Macrophage Pro-Inflammatory Polarization Via NRF2/SIRT3/SOD2/ROS Pathway in K/BxN Rheumatoid Arthritis Mice.

Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by pain, swelling, stiffness, and impaired function. Attenuating inflammation is a crucial objective in RA management. Diet and nutrition are believed to influence RA symptomatology, with a low-protein diet being one potential nutritional strategy, although its underlying mechanisms remain to be fully elucidated. In this research, serum derived from arthritic transgenic K/BxN mice was administered to naive mice to establish a K/BxN rheumatoid arthritis model. Physiological assessments and histological staining were performed to evaluate joint pathology. (Enzyme-linked immunosorbent assay) ELISA was used to measure inflammatory cytokines. Flow cytometry and immunofluorescence were applied to characterize macrophage phenotypes. Transcriptomic analysis elucidated molecular pathways under the effect of a low-protein diet and verified by immunoblotting. Mitochondrial reactive oxygen species (ROS) was detected by Mito-SOX. Protein expression was silenced through the application of siRNA transfection. Our results indicate that a low-protein diet significantly alleviates disease symptoms and decreases pro-inflammatory cytokine levels in synovial fluid. Furthermore, this dietary intervention inhibits M1 macrophage polarization while promoting a shift towards the M2 phenotype. Transcriptomic analysis revealed that the beneficial effects of the low-protein diet in alleviating rheumatoid arthritis are closely linked to the NRF2 pathway. In vitro, low protein treatment can promote the activity of NRF2 via inhibiting the ubiquitin mediated proteolysis and activate the NRF2/SIRT3/SOD2 pathway to inhibit the production of ROS, which will further inhibit the M1 macrophage polarization. NRF2 knockdown can abolish the effects of low-protein treatment, indicating that the inhibition of M1 polarization and the anti-inflammatory response induced by low-protein treatment are dependent on NRF2. In summary, our findings propose that low-protein diet can inhibit synovial macrophage M1 polarization via activating NRF2/SIRT3/SOD2 pathway to reduce mitochondrial ROS production. This mechanism effectively decreases synovial inflammation and alleviates RA symptoms.

Utilizing spontaneous plants for sustainable development in residential green spaces: Insights from environmental drivers and niche analysis in Fuzhou City, China.

This study, aimed at exploring low-maintenance, high-diversity, and sustainable greening strategies for residential areas, conducted a comprehensive survey and analysis of spontaneous plants in residential green spaces in Fuzhou City, documenting 361 species. Employing methods such as variance partitioning, Canonical Correspondence Analysis (CCA), and ecological niche analysis, we investigated the environmental factors influencing the distribution and composition of these plants, as well as their interrelationships. The study found that the composition of spontaneous plants in residential green spaces differs from other urban environments, with a high proportion of alien species (43.77%) due to influences such as resident activities, including a large number of ornamental and edible plants. Maintenance level, urbanization gradient, and green space ratio are common factors affecting the composition and distribution of spontaneous plants in urban environments, while unique residential socio-economic factors like building age, housing prices, and population density significantly affect the spontaneous plants in residential green spaces. The overall dominant plant community shows a significant positive association, indicating a relatively stable stage of succession. Although competition among most species is not significant and interspecific connectivity is weak, the presence of seven dominant invasive species intensifies competition. Based on these findings, the study proposes several specific sustainable management measures: adopting the concept of New Naturalistic Ecological Planting Design, selecting native spontaneous plants with strong adaptability, and constructing plant communities that are ecologically stable and have ornamental value by mimicking natural ecosystems. Additionally, specific methods for managing specific invasive species in residential green spaces using competitive replacement control methods are proposed. These measures aim to promote the health and sustainable development of urban residential green spaces.

Progress and evolution of hotspots in butterfly diversity research in green spaces.

Ecosystems depend on biodiversity; therefore, protecting biodiversity is beneficial for the development of ecosystems. Butterflies are indicator species that respond quickly to environmental changes and reflect environmental conditions. Butterfly diversity is a crucial evaluation indicator of habitat quality in green spaces. We used CiteSpace and Bibliometrix to conduct a bibliometric analysis of research relating to butterfly diversity in green spaces. Based on 538 papers published from 2002-2022, we systematically reviewed the status, frontiers, and hotspots for research on butterfly diversity in green spaces. Our results showed that: (1) Research on butterfly diversity in green spaces has consistently demonstrated an upward trend between 2002-2022. Studies on this subject have garnered attention from researchers worldwide, with notable interest and contributions from scholars in the United States. (2) Early studies focused on butterfly habitat preferences and extinction concerns, and later articles appeared on the influence of external environmental factors (land use, climate change, plants, etc.). (3) Three main research topics received much attention between 2002 and 2022: biodiversity conservation, butterfly habitats, and the relationship between butterfly diversity and its influencing factors. (4) The relationship between green spaces and butterfly diversity (landscape features, vegetation features, and human activities) was discussed; these factors on butterfly communities should be considered in the planning and constructing of future green spaces. (5) Two significant future directions have been identified: more research on the impact of external factors and a need for more technical integration with the big data field. Future research on butterfly diversity in green spaces should adopt a more multi-scale, multi-disciplinary approach and aim to enhance the practicality and guidance of research findings.

The microclimate impact of treetop walk based on plant community simulation.

The treetop walk is an innovative urban greenway that harmoniously integrates with the natural topography, meandering through the tree canopy. It serves as a vital element in elevating the urban mountain landscape while also significantly impacting the recreational experiences of the public through its microclimate effects. Moreover, the distinctive plant community characteristics of the treetop walk significantly enhance the microclimate. Examining the plant community attributes that potentially influence the microclimate conditions of the treetop walk is of utmost importance. We chose the Fu Forest Trail in Fuzhou as the sample site for this research. By implementing an orthogonal experimental design and using ENVI-met software, we simulated data to explore the impacts of various plant community characteristics on the microclimate of the treetop walk in autumn. The findings revealed the following results: (1) The presence of tree height, leaf area index, crown type, and planting density significantly influenced the microclimate of the treetop walk green spaces, with some factors having primary effects while others having secondary effects. (2) No significant variations were observed in the microclimate effects of diverse plant community characteristics in the treetop walk during morning, noon, and evening hours. (3) Scheme 13 emerged as the optimal choice for cooling and humidifying ventilating, characterized by a tree height of 20 m, leaf area index of 4.4, spherical crown shape, and planting spacing of 2 m. The tree species available in the Fuzhou area include Ligustrum quihoui Carr., Buxus sinica, Laurus nobilis, Myrica rubra, and Osmanthus fragrans. (4) Compared to traditional understory trails, tree height and planting spacing notably influence the microclimate environment of the treetop walk.

Construction of a cold island network for the urban heat island effect mitigation.

The urban heat island (UHI) effect seriously challenges sustainable urban development strategies and livability. Numerous studies have explored the UHI problem from the perspective of isolated blue and green patches, ignoring the overall function of cold island networks. This study aims to explore the construction method of cold island network by integrating scattered cold island resources, rationally guiding urban planning and construction, and providing effective ideas and methods for improving the urban thermal environment. Taking the central city of Fuzhou as an example, the identification of the cold island core source (CICS) was optimized by applying relative land surface temperature (LST), morphological spatial pattern analysis, and landscape connectivity analysis. The combined resistance surface was constructed based on a spatial principal component analysis. Subsequently, the cold island network was constructed by applying circuit theory and identifying the key nodes. The results showed that the central and eastern parts of the study area experienced the most significant UHI effects and there was a tendency for them to cluster. Overall, 48 core sources, 104 corridors, 89 cooling nodes, and 34 heating nodes were identified. The average LST of the CICSs was 28.43 °C, significantly lower than the average LST of the entire study area (31.50 °C), and the 104 cold corridors were classified into three categories according to their importance. Different targeting measures should be adopted for the cooling and heating nodes to maintain the stability of the cold island network and prevent the formation of a heat network. Finally, we suggest a model for urban cold island network construction and explore methods for mitigating issues with UHI to achieve proactive and organized adaptation and mitigation of thermal environmental risks in urban areas, as well as to encourage sustainable urban development.

"Adjacent Bed Effect" of Total Knee Arthroplasty Patients During the Perioperative Period.

BACKGROUND: Knee osteoarthropathy is one of the most common degenerative joint diseases in the elderly, total knee arthroplasty (TKA) is the most commonly used treatment for end-stage knee osteoarthropathy. Negative emotions such as anxiety have been extensively documented in knee osteoarthropathy patients. AIM: This study aimed to investigate the Emotional Contagion during hospitalization in patients undergoing TKA. METHODS: Eligible subjects were divided into three case groups according to their anxiety states and bed arrangement. All subjects underwent a unilateral, cemented TKA under general anesthesia. Post-operative recovery outcomes including pain, pain behavior and physical function were recorded pre-operation, 1-day, 1 week, 2-weeks, 1-month and 3-months post-operation. RESULTS: A total of 38 subjects were included in the final analysis. Subjects with anxiety had higher Visual Analogue Scale pain scores, PROMIS-Pain Behavior scores than subjects without anxiety in the Contagion Group preoperation (p ≤ .05). Non-anxiety subjects hospitalized in beds physically adjacent to anxiety subjects experienced more severe pain and poorer function (p ≤ .05). After discharge, all clinical outcomes gradually became lower than anxiety subjects in the Contagion Group, reaching levels similar to non-anxiety subjects in the No Contagion Group within 1 month (p>.05). CONCLUSIONS: This study showed that patients with anxiety may have an "Adjacent Bed Effect" on patients with TKA in the adjacent bed, which may be associated with poorer postoperative recovery, including pain and physical function. We speculate this phenomenon can be effectively avoided by the nursing team through accurately assessing psychological status and reasonable bed arrangements in the inpatient assessment phase.

The Impact of Urbanization on Taxonomic Diversity and Functional Similarity among Butterfly Communities in Waterfront Green Spaces.

Urbanization has been shown to cause biodiversity loss. However, its effects on butterfly taxonomic and functional diversity still need to be studied, especially in urban waterfront green spaces where mechanisms of impact still need to be explored. We used butterflies as indicators to study how urbanization affects their taxonomic and functional diversity and identify indicator species in different urban ecological gradient areas. From July to September 2022, we surveyed 10 urban waterfront green spaces in Fuzhou City, China. We recorded 1163 butterflies of 28 species from 6 families. First, we explored the effects of urbanization on butterfly communities and made pairwise comparisons of different urban ecological gradients (α-diversity); secondly, we looked for differences between butterfly communities across urban ecological gradients (ß-diversity); finally, we investigated differences in the response of butterfly functional groups to different urban ecological gradient areas and identified ecological indicative species. This study found the following: (1) Urbanization has led to the simplification of butterfly community structure, but there are also favorable factors that support the survival of individual butterflies; (2) Urbanization has led to significant differences in butterfly communities and plant-feeding polyphagous butterfly groups; (3) Urbanization has led to differences in the functional diversity of butterfly diet and activity space groups; (4) We identified five eco-indicator species in different urban ecological gradients.

[Application of femoral I.D.E.A.L localization in anterior cruciate ligament reconstruction with single bundle anterior cruciate ligament].

OBJECTIVE: To evaluate the effect of femoral I.D.E.A.L localization in single bundle anterior cruciate ligament reconstruction (ACLR). METHODS: From January 2019 to October 2022, 122 patients with anterior cruciate ligament injury were treated with ACLR, including 83 males and 39 females. The age ranged from 23 to 43 years old, with an average of (32.19 ±8.55) years old. The course of disease ranged from 1 week to 6 months. According to the different surgical schemes, the patients were divided into two groups, namely the traditional group, which adopted the over-the-top femoral lateral positioning scheme, including 64 patients. The I.D.E.A.L group adopted the I.D.E.A.L femoral lateral positioning scheme, including 58 patients. The patient has pain and dysfunction of knee joint before operation. MRI of knee joint indicates anterior cruciate ligament injury. The visual analogue scale(VAS), International Knee Documentation Committee(IKDC) scoring system and Lysholm scoring system were used to evaluate the knee joint function of the patient. KT-2000 was used to detect the recovery of knee joint after operation and to count the postoperative complications. RESULTS: The wounds healed well after operation. One hundred and twenty-tow patients were followed up for 15 to 46 months, with an average of (25.45±9.22) months. The knee joint stability of patients after operation was significantly increased. The VAS at 1 day and 1 week after operation of patients in the I.D.E.A.L group was significantly lower than that in the traditional group(P<0.05). The IKDC score and Lysholm score of patients in the I.D.E.A.L group were significantly higher than those in the traditional group(P<0.05). In the traditional group, there were 6 cases of short-term (<1 month) complications and 19 cases of long-term (≥1 month)complicatios. In the I.D.E.A.L group, there were 3 cases of short-term complications and 7cases of long-term complications(P<0.05). CONCLUSION: The single bundle anterior cruciate ligament reconstruction and femoral I.D.E.A.L positioning can achieve better early postoperative effect and reduce early postoperative pain.

Butterfly Communities Vary under Different Urbanization Types in City Parks.

Butterflies are key indicators of urban biodiversity and one of the most vulnerable organism groups to environmental changes. Studying how butterflies are distributed and what factors might influence them in urban green spaces is crucial. In this study, from July 2022 to September 2022, we examined and analyzed the butterfly diversity in nine parks in Fuzhou, China, along three different levels of urbanization (urban, peri-urban, and suburban). We investigated how butterfly communities respond to increasing urbanization. The findings revealed that: (1) A total of 427 butterfly individuals from 4 families and 13 species were observed; (2) Shannon diversity, richness, and abundance of the overall butterfly community were lower in the more urbanized parks. Urbanization had significant effects on Shannon diversity (p = 0.003) and abundance (p = 0.007) but no significant effects on the whole butterfly community richness (p = 0.241); (3) non-metric multidimensional scaling revealed that there were differences in the overall number of butterfly species in urban parks among different geographic regions.

How does 2D and 3D of urban morphology affect the seasonal land surface temperature in Island City? A block-scale perspective.

The global climate warming caused by urbanization has significantly affected the urban environment. Whilst land surface temperature (LST) is an important factor reflecting urban temperature, previous research on LST mostly focused on two-dimensional (2D) factors and rarely mentioned about the role of three-dimensional (3D) factors, particularly the LST variation characteristics of island cities. Therefore, this study examined the seasonal variation characteristics of urban LST by analyzing the impact of 2D and 3D urban morphology factors of different urban block types on LST in Xiamen Island. The main results are as follows. First, compact low layer (CL), a block type with a higher density of low-rise buildings, has a higher LST in any season. Under the same block density (BD), the higher the block average height (BH), the lower the LST. Second, among the 2D urban morphology factors, normalized difference vegetation index (NDVI) was the main factor for cities to reduce urban LST, especially in summer, while normalized difference built-up index (NDBI) was the opposite. Different from land cities, we found a positive correlation between modified normalized difference water body index (MNDWI) and LST in autumn and winter. Third, in the 3D urban morphology factors, sky view factor (SVF) was significantly positively correlated with LST, while building fluctuation (BF) was negatively correlated. The higher the SVF, the worse the radiation shielding effect between buildings. On the contrary, the higher the BF, the higher the building undulation, and the better the building radiation shielding. These findings should provide some quantitative insights for the future construction and planning of island cities, which can be used to improve the thermal environment of island cities and support the sustainable development of cities.

Assessing and optimizing the hydrological performance of Grey-Green infrastructure systems in response to climate change and non-stationary time series.

Climate change has led to the increased intensity and frequency of extreme meteorological events, threatening the drainage capacity in urban catchments and densely built-up cities. To alleviate urban flooding disasters, strategies coupled with green and grey infrastructure have been proposed to support urban stormwater management. However, most strategies rely largely on diachronic rainfall data and ignore long-term climate change impacts. This study described a novel framework to assess and to identify the optimal solution in response to uncertainties following climate change. The assessment framework consists of three components: (1) assess and process climate data to generate long-term time series of meteorological parameters under different climate conditions; (2) optimise the design of Grey-Green infrastructure systems to establish the optimal design solutions; and (3) perform a multi-criteria assessment of economic and hydrological performance to support decision-making. A case study in Guangzhou, China was carried out to demonstrate the usability and application processes of the framework. The results of the case study illustrated that the optimised Grey-Green infrastructure could save life cycle costs and reduce total outflow (56-66%), peak flow (22-85%), and TSS (more than 60%) compared to the fully centralised grey infrastructure system, indicating its high superior in economic competitiveness and hydrological performance under climate uncertainties. In terms of spatial configuration, the contribution of green infrastructure appeared not as critical as the adoption of decentralisation of the drainage networks. Furthermore, under extreme drought scenarios, the decentralised infrastructure system exhibited an exceptionally high degree of removal performance for non-point source pollutants.

Effects of Landscape Features on Bird Community in Winter Urban Parks.

Urban parks, as critical components of the urban green space, have practical significance in studying the influence of landscape characteristics on birds. Nine urban parks in Fuzhou, China, were used as study objects to explore the influence of landscape features (patch, landscape, and surrounding environment indices) on bird communities. The results showed that (1) from December 2021 to February 2022, we found a total of 2874 individuals belonging to 61 species of 9 orders, 32 families, which were dominated by the birds of Passeriformes (37 species of 24 families, accounting for 89.91% of the total number of individuals) and resident birds in Fuzhou urban parks (n = 30; 85.46%); (2) The park area, park perimeter, woodland area, grassland area, and the park shape index increased as the distance to the city center increases; (3) Bird diversity responds differently to different landscape features. The total abundance of birds, the abundance of winter migrant birds, and the richness of winter migrant birds increased with the park area. And the park shape index affects positively for the the α-diversity of birds and the abundance of resident birds. Woodland proportion and waterbody shape index affected positively on the richness and α-diversity of resident birds. To promote the diversity of regional birds, it is recommended that the construction and planning of urban parks should enlarge the park area as much as possible, increase the proportion of woodland, and make shorelines more irregular. Our study could serve as a reference for the construction of biodiversity enhancements in core green areas of urban parks.

Relationship between Vegetation Habitats and Bird Communities in Urban Mountain Parks.

The coastal areas of southeast China have typical high-density urbanization characteristics, and urban mountain parks are important green spaces in these urban green space systems. Our study was conducted in five typical urban mountain parks in Fuzhou, China. The bird survey was carried out in 25 transects of different vegetation habitats for 10 months, and the vegetation survey was conducted in 25 habitats to investigate the characteristics of bird communities in different vegetation habitats and the causes of their differences. The results showed: (1) From 1 October 2021 to 15 July 2022, we recorded a total of 90 bird species in 8 orders, 37 families, and 64 genera, with 1879 individuals in five vegetation habitats in the urban mountain parks. (2) Abundance and diversity of trees are vegetation variables affecting bird diversity (bird species richness, abundance, and Shannon diversity) in urban mountain parks, and the average branch height under trees has a significant effect on bird evenness. (3) We found more bird species and higher bird diversity in both sparse and dense forest habitats, but fewer bird species in waterfront, shrub, and grassland habitats; (4) Average tree height (AVE_HEIt) was only present in the best model of bird abundance and evenness. However, none of the best models found a significant effect of the number of tourists and predators on bird diversity. Our results could provide a theoretical basis and guidance for the future improvement of ecological service functions of bird habitats in urban mountain parks in subtropical coastal areas.

Does Bird Diversity Affect Public Mental Health in Urban Mountain Parks?-A Case Study in Fuzhou City, China.

Intensified urbanization has caused a linear decline in the quality of urban biodiversity and indirectly harms our current human settlement environment. Urban mountain parks provide a refuge for the animals and plants and play a vital role in satisfying residents' lives. At present, few studies are focusing on the impact of biodiversity on human mental health benefits of urban mountain parks in high-density construction areas along the coast of the Eastern Hemisphere. Here, we examined the relationship between bird abundance, Shannon diversity, Simpson diversity, and Richness and momentary mental health (positive, negative, and anxiety) in urban mountain parks. The timed species counts method was used to conduct three surveys of birds in urban mountain parks, and linear regression was performed on the relationship between bird diversity and mental health among sites. According to the regression model results, we found no significant correlation in any disturbance levels. As urban mountain parks are an essential part of the human settlement environment, how to improve the biodiversity and mental health of urban mountain parks is one of the focuses of research on biodiversity well-being in the future. Urban planning authorities and public mental health researchers should pay attention to the importance of biodiversity in urban development and consider how to realize the beautiful vision of the harmonious coexistence of humans, animals, plants, and the environment in which we live.

MiRNA-1271-5p regulates osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by targeting forkhead box O1 (FOXO1).

Forkhead box O1 (FOXO1) is a key regulator of osteogenesis. The aim of this study was to identify the mechanisms of microRNAs (miRNAs) targeting FOXO1 in osteogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs). Three miRNA target prediction programs were used to search for potential miRNAs that target FOXO1. Quantitative real-time polymerase chain reaction was conducted to detect the expression of miR-1271-5p and FOXO1 during osteogenic differentiation. Target gene prediction and screening, luciferase reporter assay was used to verify the downstream target gene of miR-1271-5p. The expression levels of FOXO1 and Runx2 were detected by RT-qPCR and Western blot analysis. Alkaline phosphatase (ALP) activity and matrix mineralization were detected by biochemical methods. The expression levels of Runx2, ALP, and osteocalcin were detected by RT-qPCR. Our results showed that miR-1271-5p was downregulated during osteogenic induction. And the expression levels of miR-1271-5p were higher in osteoporotic tissues than that in adjacent nonosteoporotic tissues. The expression levels of FOXO1 were lower in osteoporotic tissues than that in adjacent nonosteoporotic tissues. And a negative correlation was found between miR-1271-5p and FOXO1 in osteoporotic tissues. Overexpression of miR-1271-5p downregulated FOXO1 and inhibited osteogenic differentiation in hMSCs. Overexpression of miR-1271-5p downregulated the expression of osteogenic markers and reduced ALP activity. In addition, ectopic expression of FOXO1 reversed the effect of miR-1271-5p on osteogenic differentiation. In conclusion, miR-1271-5p functioned as a therapeutic target of osteogenic differentiation in hMSCs by inhibiting FOXO1, which provides valuable insights into the use of miR-1271-5p as a target in the treatment of osteoporosis and other bone metabolic diseases.

CRISPR/Cas9 facilitates genomic editing for large-scale functional studies in pluripotent stem cell cultures.

Pluripotent stem cell (PSC) cultures form an integral part of biomedical and medical research due to their capacity to rapidly proliferate and differentiate into hundreds of highly specialized cell types. This makes them a highly useful tool in exploring human physiology and disease. Genomic editing of PSC cultures is an essential method of attaining answers to basic physiological functions, developing in vitro models of human disease, and exploring potential therapeutic strategies and the identification of drug targets. Achieving reliable and efficient genomic editing is an important aspect of using large-scale PSC cultures. The CRISPR/Cas9 genomic editing tool has facilitated highly efficient gene knockout, gene correction, or gene modifications through the design and use of single-guide RNAs which are delivered to the target DNA via Cas9. CRISPR/Cas9 modification of PSCs has furthered the understanding of basic physiology and has been utilized to develop in vitro disease models, to test therapeutic strategies, and to facilitate regenerative or tissue repair approaches. In this review, we discuss the benefits of the CRISPR/Cas9 system in large-scale PSC cultures.

Downregulation of microRNA-23b-3p alleviates IL-1ß-induced injury in chondrogenic CHON-001 cells.

BACKGROUND: Osteoarthritis (OA) is a common joint disease, which is characterized by degradation of articular cartilage. Evidence indicated that miR-23b-3p was upregulated in cartilage tissues of a patient with OA. However, the mechanism by which miR-23b-3p regulates the occurrence and development of OA remains unclear. Thus, this study aimed to investigate the role of miR-23b-3p in the progression of OA. METHODS: In this study, qRT-PCR was used to measure the expression of miR-23b-3p in OA tissue samples and normal controls, respectively. Western blotting assay was performed to detect the levels of collagen II, aggrecan, Bax and active caspase 3 in CHON-001 cells. In addition, the dual-luciferase reporter system assay was used to detect the interaction between miR-23b-3p and COL11A2 in OA. RESULTS: The levels of miR-23b-3p were upregulated, while the expressions of collagen II and aggrecan were decreased in OA tissues and in IL-1ß-treated CHON-001 cells. In addition, IL-1ß significantly induced apoptosis of CHON-001 cells via increasing the levels of Bax and active caspase 3. However, downregulation of miR-23b-3p markedly inhibited IL-1ß-induced apoptosis in CHON-001 cells via increasing the collagen II and aggrecan levels and decreasing Bax and active caspase 3 expressions. Meanwhile, dual-luciferase assay showed that COL11A2 was the direct target of miR-23b-3p in CHON-001 cells. Overexpression of miR-23b-3p markedly decreased the level of COL11A2 in cells. Moreover, downregulation of miR-23b-3p alleviated synovitis/cartilage destruction and reduced Osteoarthritis Research Society International scores and subchondral bone thickness in vivo. CONCLUSION: Downregulation of miR-23b-3p could alleviate the progression of OA through upregulating COL11A2 in vivo and in vitro. Therefore, downregulation of miR-23b-3p might be a potential therapeutic strategy for the treatment of OA.

Up-regulated HIF-2α contributes to the Osteoarthritis development through mediating the primary cilia loss.

BACKGROUNDS: Up-regulated HIF-2α (hypoxia induced factor 2) had been demonstrated to contribute to Osteoarthritis (OA) development via inducing the expression of matrix-degrading enzymes. However, the HIF-2α also could promote primary cilia loss through HIF-2α/AURKA (Aurora kinase A)/NEDD9 pathway. And the primary cilia dysfunction is another characteristic of the OA. Thus, we investigated here whether the HIF-2α also contributes the OA development through mediating the primary cilia loss. METHODS: The primary chondrocytes were isolated from the experimental OA mice induced by destabilization of the medial meniscus (DMM). Chondrocytes were cultured under normoxia (21% O2) or hypoxia (2% O2) conditions. The HIF-1α and HIF-2α expressions were assessed by western blot. The cilia formation was counted by immuno-staining the acetylated tubulin. The contribution of HIF-1α or HIF-2α to the primary cilia loss was assessed by knocking-down the HIF-1α or HIF-2α individually. The HIF-2α/AURKA/NEDD9 pathway was validated through over-expressing or knocking-down specific components of the pathway and then counting the primary cilia number. Finally, the pathway was further confirmed in the OA mice. RESULTS: Hypoxia could induce the expression of both HIF-1α and HIF-2α, and also reduce the number of primary cilia on the chondrocytes isolated from the experimental OA mice. Knocking-down or over-expressing HIF-1α or HIF-2α individually showed that the HIF-2α could induce the primary cilia reduction rather than the HIF-1α. Manipulating the HIF-2α expression could positively affect the AURKA and NEDD9 expression. Manipulating the AURKA and NEDD9 expressions could reverse the function of HIF-2α on primary cilia. In the mice, knocking-down both AURKA and NEDD9 could alleviate the OA development significantly. CONCLUSION: Up-regulated HIF-2α contributes to the Osteoarthritis development through mediating the primary cilia loss, which might be developed as therapeutic targets for OA treatment.

A LINC00341-mediated regulatory pathway supports chondrocyte survival and may prevent osteoarthritis progression.

Osteoarthritis (OA) is the most common degenerative joint disease and results from progressive loss and destruction of articular cartilage and the underlying bone. The disease affects millions of people worldwide with an associated risk of mobility disability. However, the molecular basis underlying OA initiation and progression is not well understood and, currently, there is no effective intervention available to decelerate disease progression or restore degraded cartilage. We have found that lncRNA long intergenic nonprotein coding RNA 341 (LINC00341) is aberrantly downregulated in OA patient tissues and cultured OA chondrocytes. This is likely responsible for the increased apoptosis of chondrocytes and pathological destruction of cartilage. Further investigation has revealed that LINC00341 interacts with miR-141 to suppress its functional binding to the 3'-untranslated region of YY1-associated factor 2 (YAF2) messenger RNA. Aberrant downregulation of LINC00341 thus may ultimately lead to inhibition of the YAF2 protein, which has been implicated to be an antiapoptotic factor. Our study has revealed a new noncoding RNA-mediated regulatory network that highly likely protects chondrocytes by preventing apoptosis under normal conditions. The results will help further explore the molecular details pertaining to the progression of OA and stimulate efforts to develop effective therapies.

Study on the mechanism of excessive apoptosis of nucleus pulposus cells induced by shRNA-Piezo1 under abnormal mechanical stretch stress.

OBJECTIVE: The aim of the study was to explore the mechanism of excessive apoptosis of nucleus pulposus cells induced by short hairpin RNA (shRNA) Piezo type mechanosensitive ion channel component 1 (Piezo1) under abnormal mechanical stretch stress. METHODS: In vitro mechanical stretch stress model of nucleus pulposus cells in vitro was established, in which the expression of Piezo1 was interfered by transfection of shRNA-Piezo1 interfering vector. Both messenger RNA and protein level of Piezo1 were measured by reverse-transcription polymerase chain reaction and Western blot analysis, respectively. Cytoplasmic Ca2+ was detected by Fluo3-AM kit, and changes of mitochondrial membrane potential in cells were detected using Cell Meter Assay kit. Finally, the apoptosis was evaluated with annexin V-fluorescein isothiocyanate kit. RESULTS: The highest transfection efficiency of lentivirus titer was 1 × 10 TU/mL and the nucleus pulposus cells were transfected with plural multiplicity of infection = 50. Homo-3201 sequence exhibited the most effective silencing effect and was used in subsequent experiments as the default sequence of shRNA-Piezo1. The calcium content in the cytoplasm of the tension stress group increased significantly compared with that in the blank control group ( q = 3.773; P < 0.05). The level of cytosolic calcium in shRNA-interference group was significantly lower than that in stretch stress group ( q = 5.159; P < 0.05). Stretch stress treatment resulted in an elevated ratio of mitochondrial membrane potential turnover as opposed to blank control group ( q = 4.332; P < 0.05), while shRNA-interference group showed smaller ratio of mitochondrial membrane potential turnover than that in stretch stress group ( q = 4.974; P < 0.05). Similar results were also observed in apoptosis rate analysis ( q = 3.175; P < 0.05). CONCLUSION: ShRNA-Piezo1 can protect cells by reducing the level of intracellular Ca2+ and the change of mitochondrial membrane potential.