Effects of sodium selenite on c-Jun N-terminal kinase signalling pathway induced by oxidative stress in human chondrocytes and c-Jun N-terminal kinase expression in patients with Kashin-Beck disease, an endemic osteoarthritis

Cascade targeting selenium nanoparticles-loaded hydrogel microspheres for multifaceted antioxidant defense in osteoarthritis

Selenium (Se) deficiency is a critical factor contributing to the imbalance of redox homeostasis in chondrocytes and the progression of osteoarthritis (OA). However, traditional selenium supplements face challenges such as a narrow therapeutic window and lack of targeting. To address this, we designed hyaluronic acid (HA)-modified selenium nanoparticles (HA-SeNPs) and developed a cascade-targeted delivery system (HA-SeNPs@AHAMA-HMs) based on a nano-micron combined strategy. The system involves loading HA-SeNPs into aldehyde-functionalized hydrogel microspheres prepared via microfluidic technology. Through Schiff base reactions between the aldehyde groups of the microspheres and amino groups of the cartilage, the system selectively adheres to the surface of damaged cartilage, achieving micron-scale targeting while continuously releasing HA-SeNPs. Then, HA-SeNPs achieve nanoscale targeting by binding to CD44, which is highly expressed on OA chondrocyte membranes, via their HA surface. Once taken up by the cells, HA-SeNPs exert their effects by directly scavenging ROS and promoting selenoprotein synthesis through the generation of selenite, forming a multifaceted antioxidant defense system. This effectively alleviates oxidative stress and optimizes mitochondrial function. In vivo and in vitro results demonstrated that this system significantly improved the oxidative phosphorylation pathway associated with mitochondrial function, which markedly reduced joint space narrowing and cartilage matrix degradation, and delayed the progression of OA. In summary, this study suggests that the cascade-targeting hydrogel microspheres designed and constructed based on a nano-micron combined strategy represent a promising prospective approach for precise Se supplementation and OA treatment.

Targets and Potential Mechanism of Chondroitin Sulfate A-selenium Nanoparticle on Kashin-Beck Disease Chondrocytes

Kashin-Beck disease (KBD) is a chronic and deformable osteoarthropathy linked to low selenium. Limited cartilage regeneration poses challenges for its treatment. Previous studies have found that chondroitin sulfate A-selenium nanoparticle (CSA-SeNP) protects chondrocytes. This study used label-free LC-MS/MS quantitative proteomics to identify differentially expressed proteins and pathways in KBD chondrocytes post-CSA-SeNP treatment. Western blot (WB) was used to verify the key differential proteins, and transmission electron microscopy (TEM) was used to observe the ultrastructure of chondrocytes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed proteins mainly involved in RNA processing, translation, peptide biosynthesis, gene expression, rRNA metabolism, and ribonucleoprotein complex biogenesis. Notably, 121 proteins were up-regulated, 27 down-regulated, and 117 specifically expressed in the CSA-SeNP group. Enriched KEGG pathways included ribosome biogenesis, mRNA surveillance, endoplasmic reticulum protein processing, and endocytosis. Proteins related to autophagy, ER stress, cell homeostasis, protein processing and transport, including PELO, WES1, PLAA, RRBP1, ARC1B, ARFGAP2, and SH3KBP1, were significantly up-regulated in the CSA-SeNP group. In conclusion, our results demonstrated that CSA-SeNP may exert protective effects on chondrocytes in adult patients with KBD mainly through the regulation of target proteins and pathways related to ribosome biogenesis, mRNA surveillance, endoplasmic reticulum protein processing, endocytosis, autophagy, ER stress, and cell homeostasis. Further studies with larger sample size and in vivo to identify, screen and verify the regulatory effects of target proteins and pathways may provide more information for elucidating the mechanism of CSA-SeNP in the treatment of KBD.

MiR-140 is involved in T-2 toxin-induced matrix degradation of articular cartilage

T-2 toxin is one of the most toxic mycotoxins contaminating various grains. It is considered an environmental risk factor for Kashin-Beck disease (KBD), an endemic degenerative osteochondrosis. Currently, the underlying molecular mechanisms of articular cartilage damage caused by T-2 toxin have not been elucidated. Studies have shown that miR-140 is essential for cartilage formation, and extracellular matrix (EMC) synthesis and degradation. The objective of this study was to investigate the mechanism of miR-140 involvement in T-2 toxin-induced articular cartilage damage. Two treatment groups, each containing wild-type mice and miR-140 knockout mice were administered with T-2 toxin (200 ng/g BW/day) or a normal diet for 1 month, 3 months, and 6 months. Results showed that T-2 toxin caused articular cartilage and growth plate damage in mice. The expression of miR-140 decreased in articular cartilage of wild-type mice treated with T-2 toxin, and miR-140 deficiency aggravated T-2 toxin-induced knee cartilage damage. T-2 toxin-caused the reduction of miR-140 expression was consistent with collagen type II (COL2A1), aggrecan (ACAN), and SRY-box containing gene 9 (SOX9) and opposite to matrix metalloproteinase 13 (MMP13), a disintegrin and metalloproteinase with thrombospondin motif 5 (ADAMTS-5), and v-ral simian leukemia viral oncogene homolog A (RALA). In addition, we collected finger joints cartilage and knee joints cartilage from KBD patients and controls for paraffin embedding and sectioning. Results found that the expression of miR-140 in the articular cartilage of the KBD group was lower than that of the control group. The expression of COL2A1, ACAN, and SOX9 decreased, whereas ADAMTS-5, MMP13, and RALA increased in the articular cartilage of the KBD group. These results revealed that miR-140 might be involved in T-2 toxin-induced degradation of the ECM of articular cartilage. Moreover, the occurrence of KBD might be related to the decreased expression of miR-140 in articular cartilage.

MD2 Inhibits Choroidal Neovascularization via Antagonizing TLR4/MD2 Mediated Signaling Pathway

PURPOSE

To explore the pathological mechanism of Toll-like receptor 4 (TLR4) mediating neovascular age-related macular degeneration (nAMD) and the potential role of the TLR4 coreceptor myeloid differentiation protein 2 (MD2).

METHODS

In the study, we inhibited MD2 with the chalcone derivative L2H17 and we utilized a laser-induced choroidal neovascularization (CNV) mouse model and Tert-butyl hydroperoxide (TBHP)-challenged rhesus choroid-retinal endothelial (RF/6A) cells to assess the effect of MD2 blockade on CNV.

RESULTS

Inhibiting MD2 with L2H17 reduced angiogenesis in CNV mice, and significantly protected against retinal dysfunction. In retina and choroid/retinal pigment epithelium (RPE) tissues, L2H17 reduced phospho-ERK, phospho-P65 but not phospho-P38, phospho-JNK, and reduced the transcriptional levels of IL-6, TNF-α, ICAM-1 but not VCAM-1. L2H17 could protect RF/6A against TBHP-induced inflammation, oxidative stress, and apoptosis, via inhibiting the TLR4/MD2 signaling pathway and the following downstream mitogen-activated protein kinase (MAPK) and nuclear transcription factor-κB (NF-κB) activation.

CONCLUSIONS

Inhibiting MD2 with L2H17 significantly reduced CNV, suppressed inflammation, and oxidative stress by antagonizing TLR4/MD2 pathway in an MD2-dependent manner. MD2 may be a potential therapeutic target and L2H17 may offer an alternative treatment strategy for nAMD.

Detection of selenoprotein transcriptome in chondrocytes of patients with Kashin-Beck disease

Background: Kashin-Beck disease (KBD) is a deformed osteochondral disease with a chronic progression that is restrictively distributed in eastern Siberia, North Korea, and some areas of China, and selenium deficiency has been identified as an important factor in the pathogenesis of this disease in recent years. Objective: The aim of this study is to investigate the selenoprotein transcriptome in chondrocytes and define the contribution of selenoprotein to KBD pathogenesis. Methods: Three cartilage samples were collected from the lateral tibial plateau of adult KBD patients and normal controls paired by age and sex for real-time quantitative polymerase chain reaction (RT-qPCR) to detect the mRNA expression of 25 selenoprotein genes in chondrocytes. Six other samples were collected from adult KBD patients and normal controls. In addition, immunohistochemistry was used on four adolescent KBD samples and seven normal controls (IHC) to determine the expression of proteins screened by RT-qPCR results that had different gene levels. Results: Increased mRNA expression of GPX1 and GPX3 was observed in chondrocytes, and stronger positive staining was displayed in the cartilage from both adult and adolescent patients. The mRNA levels of DIO1, DIO2, and DIO3 were increased in KBD chondrocytes; however, the percentage of positive staining decreased in the KBD cartilage of adults. Conclusion: The selenoprotein transcriptome, mainly the glutathione peroxidase (GPX) and deiodinase (DIO) families were altered in KBD and might play a vital role in the pathogenesis of KBD.

Progress of Selenium Deficiency in the Pathogenesis of Arthropathies and Selenium Supplement for Their Treatment

Selenium, an essential trace element for human health, exerts an indispensable effect in maintaining physiological homeostasis and functions in the body. Selenium deficiency is associated with arthropathies, such as Kashin-Beck disease, rheumatoid arthritis, osteoarthritis, and osteoporosis. Selenium deficiency mainly affects the normal physiological state of bone and cartilage through oxidative stress reaction and immune reaction. This review aims to explore the role of selenium deficiency and its mechanisms existed in the pathogenesis of arthropathies. Meanwhile, this review also summarized various experiments to highlight the crucial functions of selenium in maintaining the homeostasis of bone and cartilage.

CpG methylation of the GPX3 promoter in patients with Kashin-Beck Disease potentially promotes chondrocyte apoptosis

OBJECTIVE

To determine the methylation levels of CpGs in the GPX3 promoter region and explore their potential effects on the apoptosis of chondrocytes.

METHODS

Blood specimens were collected from 32 participants; 16 KBD patients and 16 healthy subjects. Twenty-five CpGs in the promoter region of GPX3 were identified and detected by MALDI-TOF-MS. Methylation levels of CpGs were compared between KBD patients and healthy subjects as well as among the KBD patients with different degrees. C28/I2 human chondrocytes were treated with tBHP and Na2SeO3. Apoptosis in chondrocytes was examined under a fluorescence microscope.

RESULTS

The methylation levels of GPX3-1_CpG_11 and GPX3-1_CpG_16 in KBD patients were significantly higher than those of healthy subjects (P < 0.05). The methylation levels of the other CpGs were not significantly different between the two groups (P > 0.05). The methylation level of GPX3-1_CpG_24 in KBD patients was significantly higher than those of healthy subjects (P < 0.05). MSP-PCR analysis indicated that the methylation rate of KBD group (9.41%) was significantly higher than that of healthy subjects (1.18%), and that GPX3 DNA methylation increased the risk of acquiring KBD 8 fold (OR = 8.000, 95% CI: 1.023-62.580); The mRNA expression of GPX3 in whole blood of KBD patients was lower than that of healthy subjects (P＜0.05); Compared with the control group, GPX3, GPX1 and GPX4 mRNA level of the tertbutyl hydroperoxide injury group decreased significantly (P < 0.05), after supplementation with Na2SeO3. The rate of chondrocytes apoptosis was decreased with the increasing of GPX3 and GPX4 mRNA levels (P＜0.05) and GPX3 mRNA showed a similar trend without statistically significant (P＞0.05).

CONCLUSION

The methylation patterns of CpGs in GPX3 varied in KBD patients. The experiments indicated that the increased methylation of CpGs within the GPX3 promoter may down-regulate the expression of GPX3, thereby reducing the antioxidant function of GPX3 and promoting chondrocyte apoptosis, both of which accelerates the occurrence of KBD. We therefore propose a new understanding of GPX3's potential epigenetic and genetic mechanisms that contribute to KBD.

Hyaluronic Acid Modified Curcumin-Loaded Chitosan Nanoparticles Inhibit Chondrocyte Apoptosis to Attenuate Osteoarthritis via Upregulation of Activator Protein 1 and RUNX Family Transcription Factor 2

Hyaluronic acid (HA) and curcumin (CUR) have been previously utilized for osteoarthritis (OA) treatment. CUR-loaded chitosan nanoparticles (CUR@CS NPs) and HA CUR@CS NPs were synthesized in our research to ascertain the synergistic impacts of HA and CUR-loaded NPs on OA treatment. CUR@CS NPs and HA CUR@CS NPs were synthesized with evaluation of their particle size, potential, PDI, encapsulation efficiency, drug loading and surface coating as well as HA binding rate. The in vitro CUR release curve and stability of HA-CUR@CS NPs were measured. Chondrocytes were isolated from the cartilages of OA patients, followed by cell uptake assay. The chondrocyte viability and apoptosis were determined. Subsequently, the knee OA model was established, followed by H&E, Safranin O/Fast green staining and micro-CT. HA CUR@CS NPs improved CUR stability and bioavailability. CUR@CS NPs and HA-CUR@CS NPs were successfully characterized and could further be internalized by chondrocytes. CUR@CS NPs promoted tBHP-induced chondrocyte viability and inhibited chondrocyte apoptosis. HA-CUR@CS NPs upregulated the AP-1 and RUNX2 transcription levels to activate Hedgehog pathway, which subsequently blocked the Notch pathway. Mechanically, HA-CUR@CS NPs sustained release and long-lasting effect and long-term retention in the joint cavity and downregulated the expression of several pro-inflammatory cytokines in vivo. HA-CUR@CS NPs exhibited superior effects in the preceding experiments than CUR@CS NPs. Altogether, HA-CUR@CS NPs may restrict inflammation and chondrocyte apoptosis in OA through upregulation of AP-1 and RUNX2.

Patients with Osteoarthritis and Kashin-Beck Disease Display Distinct CpG Methylation Profiles in the DIO2, GPX3, and TXRND1 Promoter Regions

OBJECTIVE

We aimed to analyze deoxycytidine-deoxyguanosine dinucleotide (CpGs) methylation profiles in DIO2, GPX3, and TXNRD1 promoter regions in osteoarthritis (OA) and Kashin-Beck disease (KBD) patients.

METHODS

Blood samples were collected from 16 primary OA patients and corresponding 16 healthy individuals and analyzed for methylations in the CpGs of DIO2, GPX3, and TXNRD1 promoter regions using MALDI-TOF-MS. The methylation profiles of these regions were then compared between OA and KBD patients.

RESULTS

DIO2-1_CpG_2 and DIO2-1_CpG_3 methylations were significantly lower in OA than KBD patients (P < 0.05). A similar trend was observed for GPX3-1_CpG_4, GPX3-1_CpG_7, GPX3-1_CpG_8.9.10, GPX3-1_CpG_13.14.15 and GPX3-1_CpG_16 (P < 0.05) as well as TXNRD1-1_CpG_1 and TXNRD1-1_CpG_2 methylation between OA and KBD patients (P < 0.05). However, there was no difference in methylation levels of other CpGs between the 2 groups (P > 0.05).

CONCLUSION

OA and KBD patients display distinct methylation profiles in the CpG sites of DIO2, GPX3, and TXNRD1 promoter regions. These findings provide a strong background and new perspective for future studies on mechanisms underlying epigenetic regulation of selenoprotein genes associated with OA and KBD diseases.

Hydrogen (H2) Alleviates Osteoarthritis by Inhibiting Apoptosis and Inflammation via the JNK Signaling Pathway

BACKGROUND

Osteoarthritis (OA) is a very common condition and leads to joint pain, disability, and price tag all over the world. Pathogenesis of OA is closely related to numerous inflammatory and apoptosis cytokines. Hydrogen (H2) reportedly exhibits a diversity of effects such as anti-apoptotic, anti-inflammatory, and anti-oxidative properties via the JNK pathway. However, it is unknown whether H2 has a protective effect against OA via the JNK signaling pathway. Therefore, the aim of this study was to figure out whether hydrogen has protective effect on chondrocyte and further explore the possible underlying mechanism.

METHODS

The chondrocytes were obtained from the human cartilage tissues. Cells were stimulated by TBHP and treated with hydrogen. In vitro treatment effects were evaluated by Western blot assay, real-time PCR, immunofluorescence and TUNEL method. We conducted mice model of destabilization of the medial meniscus (DMM) and treated with hydrogen. In vivo treatment effects were evaluated by X-ray imaging assay, safranin O (SO) staining, TUNEL staining and immunohistochemical assay.

RESULTS

Our results showed that hydrogen can inhibit inflammatory factors (ADAMTS5 and MMP13) and apoptosis factors (cleaved caspase-3, cytochrome c, and Bax) in TBHP-induced chondrocytes. Furthermore, hydrogen can suppress the activation of JNK signaling pathway, whereas the effect of hydrogen can be abolished by anisomycin (a JNK activator). In vivo results showed that hydrogen can down-regulate the expression of p-JNK and cleaved caspase-3 expression.

CONCLUSION

We uncovered that hydrogen (H2) could alleviate apoptosis response and ECM degradation in human chondrocytes via inhibiting the activation of the JNK signaling pathway. Meanwhile, in the surgically-induced DMM mice model, treatment with hydrogen (H2) performed a significant role in OA progression.

microRNA-95 knockdown inhibits epithelial-mesenchymal transition and cancer stem cell phenotype in gastric cancer cells through MAPK pathway by upregulating DUSP5

This study investigated the role of microRNA-95 (miR-95) in gastric cancer (GC) and to elucidate the underlying mechanism. Initially, bioinformatic prediction was used to predict the differentially expressed genes and related miRNAs in GC. miR-95 and DUSP5 expression was altered in GC cell line (MGC803) to evaluate their respective effects on the epithelial-mesenchymal transition (EMT) process, cellular processes (cell proliferation, migration, invasion, cell cycle, and apoptosis), cancer stem cell (CSC) phenotype, as well as tumor growth ability. It was further predicted in bioinformatic prediction and verified in GC tissue and cell line experiments that miR-95 was highly expressed in GC. miR-95 negatively regulated DUSP5, which resulted in the MAPK pathway activation. Inhibited miR-95 or overexpressed DUSP5 was observed to inhibit the levels of CSC markers (CD133, CD44, ALDH1, and Lgr5), highlighting the inhibitory role in the CSC phenotype. More important, evidence was obtained demonstrating that miR-95 knockdown or DUSP5 upregulation exerted an inhibitory effect on the EMT process, cellular processes, and tumor growth. Together these results, miR-95 knockdown inhibited GC development via DUSP5-dependent MAPK pathway.

Pathway-based network analyses and candidate genes associated with Kashin-Beck disease

To perform a comprehensive analysis focusing on the biological functions and interactions of Kashin-Beck disease (KBD)-related genes to provide information towards understanding the pathogenesis of KBD.A retrospective, integrated bioinformatics analysis was designed and conducted. First, by reviewing the literature deposited in PubMed, we identified 922 genes genetically associated with KBD. Then, biological function and network analyses were conducted with Cytoscape software. Moreover, KBD specific molecular network analysis was conducted by Cytocluster using the Molecular Complex Detection Algorithm (MCODE).The biological function enrichment analysis suggested that collagen catabolic process, protein activation cascade, cellular response to growth factor stimulus, skeletal system development, and extrinsic apoptosis played important roles in KBD development. The apoptosis pathway, NF-kappa B signaling pathway, and the glutathione metabolism pathway were significantly enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway network, suggesting that these pathways may play key roles in KBD occurrence and development. MCODE clusters showed that in top 3 clusters, 54 of KBD-related genes were included in the network and 110 candidate genes were discovered might be potentially related to KBD.The 110 candidate genes discovered in the current study may be related to the development of KBD. The expression changes of apoptosis and oxidative stress-related genes might serve as biomarkers for early diagnosis and treatment of KBD.

The study on polymorphisms of Sep15 and TrxR2 and the expression of AP-1 signaling pathway in Kashin-Beck disease

The aim of the study was to investigate the association between rs5859 in Sep15, rs1139793 in TrxR2 polymorphisms with the risks of KBD and to detect the expression of AP-1 pathway in KBD subjects and in vitro. 208 KBD and 206 control subjects were included. PCR-Restriction Fragment Length Polymorphism (RFLP), Amplification Refractory Mutation Specific-PCR (ARMS-PCR) and Western Blotting were conducted. The results showed the minor A-allele frequency of rs5859 in KBD was statistically significantly higher than that in the control group (P < 0.05). The cases carrying A-allele had a 2-fold (95%CI: 1.064-3.956) increased risk of developing KBD compared with the G-allele carriers. There was no significant difference in genotype and allele distribution of rs1139793 between KBD patients and controls (P > 0.05). The frequency of the minor A allele of rs5859 was significantly different in Chinese healthy population compared with European, African and American. The frequency of the minor A allele of rs1139793 showed significant difference when compared with African and American. The levels of JunB, JunD, P65 proteins in KBD group were higher than those in control group (P < 0.0001). The expression of JunB, JunD, P65 proteins all increased in tBHP-induced C28/I2 oxidative damage model compared with control group (P < 0.05) and decreased after Se supplementation. Our finding indicated Sep15 is a possible candidate susceptibility gene for KBD. Combined with the in vitro study, our studies reveal novel insights into the mechanism of Se supplementation as an antioxidant via inhibiting the AP-1 signaling pathway in patients with KBD.

Selenium Nanoparticles Dispersed in Phytochemical Exert Anti-Inflammatory Activity by Modulating Catalase, GPx1, and COX-2 Gene Expression in a Rheumatoid Arthritis Rat Model

BACKGROUND Literature shows that serum selenium concentration is low in rheumatoid arthritis (RA) patients. Biochemical properties of nanoparticles (NPs) are depend in its medium dispersed. Biochemical properties could effectively alter the therapeutic potential of NPs. Phytochemicals could serve as suitable medium for dispersion of NPs. P-Coumaric acid (CA) known to have anti-inflammatory activity. MATERIAL AND METHODS In the present experiment, we investigated the anti-inflammatory effect of SeNPs dispersed in 1% CA against Complete Freund's adjuvant induced RA. Celecoxib was used as a reference drug. RESULTS Selenium NPs (SeNPs) size is maintained in 1% CA solution. We observed that supplementation with 500 μg/Kg body weight (b.w.) eNPs significantly restored the levels of thiobarbituric acid reactive substances, COX-2 activity, different antioxidant enzyme activities, and inflammatory cytokines (TNF-α, IL-1β, IL-6, and MCP-1) in RA rats. The mRNA expression of antioxidant enzymes such as MnSOD, Cu/ZnSOD, ECSOD, CAT, and GPx1 was found to be downregulated, whereas COX-2 was upregulated in RA rats; however, the mRNA expression of CAT, GPx1, and COX-2 reverted back to near normal levels in SeNPs-treated animals. CONCLUSIONS The therapeutic potential of SeNPs was confirmed through histological observation of angle joints in different experimental animals. Our results collectively suggest that SeNPs dispersed in CA can be an effective therapeutic agent for inflammatory disorders like acute gouty arthritis.

The Importance of Se-Related Genes in the Chondrocyte of Kashin-Beck Disease Revealed by Whole Genomic Microarray and Network Analysis

Kashin-Beck disease (KBD) is an endemic, chronic, and degenerative osteoarthropathy. Selenium (Se) deficiency plays important role in the pathogenesis of KBD. We aimed to screen Se-related gene from chondrocytes of patients with KBD. Whole-genome oligonucleotide microarrays were used to detect differentially expressed genes. qRT-PCR was used to confirm the microarray results. Comparative Toxicogenomics Database (CTD) was used to screen Se-related genes from differentially expressed genes. Gene Ontology (GO) classifications and network analysis of Se-related genes were constituted by STRING online system. Three hundred ninety-nine differentially expressed genes were obtained from microarray. Among them, 54 Se-related genes were identified by CTD. The qRT-PCR validation showed that four genes expressed similarly with the ones in the microarray transcriptional profiles. The Se-related genes were categorized into 6 cellular components, 8 molecular functions, 44 biological processes, 10 pathways, and 1 network by STRING. The Se-related gene insulin-like growth factor binding protein 2 (IGFBP2), insulin-like growth factor binding protein 3 (IGFBP3), interleukin 6 (IL6), BCL2, apoptosis regulator (BCL2), and BCL2-associated X, apoptosis regulator (BAX), which involved in many molecular functions, biological processes, and apoptosis pathway may play important roles in the pathogenesis of KBD.

The novel chalcone analog L2H17 protects retinal ganglion cells from oxidative stress-induced apoptosis

Chalcone is a plant metabolite widely found in fruits, vegetables, spices and tea, and has anti-tumor, anti-inflammation, immunomodulation, antibacterial and anti-oxidation activities, as well as many other pharmacological and biological effects. Our team has shown that its analogs have antioxidant activity, and oxidative stress is a pathological hallmark of retinal ischemia/reperfusion injury that can lead to retinal damage and visual loss. This investigation aims to identify a chalcone that protects retinal ganglion cells in vitro from the effects of oxidative stress and examine its mechanism. Rat retinal ganglion cell-5 cells were pretreated with chalcones and then exposed to tert-butyl hydroperoxide that causes oxidative damage. Controls received dimethyl sulfoxide only or tert-butyl hydroperoxide in dimethyl sulfoxide. Only (E)-3,4-dihydroxy-2'-methylether ketone (L2H17), of the five chalcone analogs, markedly increased the survival rate of oxidatively injured RGC-5 cells. Thus, subsequent experiments only analyzed the results of the L2H17 intervention. Cell viability and apoptosis were measured. Intracellular superoxide dismutase and reactive oxygen species levels were used to assess induced oxidative stress. The mechanism of action by L2H17 was explored by measuring the ER stress/UPR pathway and the expression and localization of Nrf2. All results demonstrated that L2H17 could reduce the apoptosis of oxidatively injured cells, inhibit caspase-3 activity, increase Bcl-2 expression, decrease Bad expression, increase the activity of superoxide dismutase, inhibit the production of reactive oxygen species, increase Nrf2 immunoreactivity, and reduce the activating transcription factor 4, phospho-eukaryotic initiation factor 2 and CHOP expression. L2H17 protects retinal ganglion cells induced by oxidative stress by regulating Nrf2, which indicates that it has the potential to become a drug for retinal ischemia/reperfusion.

Dietary exosome-miR-23b may be a novel therapeutic measure for preventing Kashin-Beck disease

Previous studies have identified a close association between diet and the prevalence of Kashin-Beck disease (KBD); however, the mechanisms via which the diet protects against KBD-associated cartilage injury has remained elusive. Recent international research studies have revealed a therapeutic role of dietary exosome micro (mi)RNAs in repairing chondrocyte lesions by regulating genes and proteins associated with cellular apoptosis and extracellular matrix. Vital molecules affecting bio-functions of chondrocytes, including miR-23b and protein kinase cyclic AMP-activated catalytic subunit β, were preliminarily identified to be dysregulated in cells and cartilage tissue of KBD patients. The function of dietary exosome in the repair of chondrocyte lesions in KBD is a novel topic in this field. It is worth exploring the protective role of dietary exosome-miR-23b against chondrocyte damage through the regulation of the protein kinase A (PKA) signaling pathway. The following aims are significant in future studies: i) To verify the association between exosome and cartilage damage in KBD patients; ii) to identify whether the protective mechanism of miR-23b in cartilage damage proceeds through regulating the PKA pathway; and iii) to explore the therapeutic role of dietary exosome-miR-23b in repairing chondrocyte lesions induced by environmental risk factors. These ideas may help establish the therapeutic role and mechanisms of dietary exosome-miR-23b in repairing chondrocyte lesions at the molecular, cellular and organismal level. These studies may simultaneously elucidate the disease pathogenesis and provide evidence for novel biomarkers and therapeutic methods for KBD.

The expression of ERK and JNK in patients with an endemic osteochondropathy, Kashin-Beck disease

Kashin-Beck disease (KBD) is a chronic, endemic osteochondropathy. Its etiopathogenesis is still obscure until now. Epidemiological observation has shown that low selenium play a crucial role in the pathogenesis of KBD. Extracellular signal-regulated kinases (ERKs) and C-Jun N-terminal kinase (JNK), members of the mitogen-activated protein kinase (MAPK) superfamily, play an important role in cell proliferation and differentiation. Nuclear factor-ĸB (NF-ĸB), an important signaling mediator for inflammatory and immune responses, is involved in the regulation of osteoclastogenesis. In the present study, we investigated the expression of ERK and JNK signal molecular, as well as nuclear factor-ĸB in the pathogenesis of Kashin-Beck disease, evaluated the effect of selenium on ERK signal pathway. The expression levels of ERK and JNK signal pathway, as well as nuclear factor-ĸB were investigated for 218 patients and 209 controls by immunoblot analysis in whole blood. Evaluated the effect of selenium on ERK signal pathway by Na₂SeO₃ treatment. The protein levels of pRaf-1, pMek1/2 and pErk1/2 decreased significantly in KBD patients, p-JNK and NF-ĸB increased in KBD patients. Furthermore, Na₂SeO₃ treatment improved the reduction of proteins in ERK signal pathway. These findings indicated that ERK and JNK signaling pathways, as well as the expression level of NF-κB signaling molecular are important contributor to the pathogenesis of KBD. Selenium stimulates the phosphorylation of the ERK signaling pathway.