Anti-inflammatory Effect of DNA Polymeric Molecules in a Cell Model of Osteoarthritis

Exposure to an enriched environment modulates the synaptic vesicle cycle in a mouse spinal cord injury model

Spinal cord injury (SCI) leads to motor and sensory impairment below the site of injury, thereby necessitating rehabilitation. An enriched environment (EE) increases social interaction and locomotor activity in a mouse model, similar to human rehabilitation. However, the impact of EE on presynaptic plasticity in gene expression levels remains unclear. Hence, this study aimed to investigate the therapeutic potential of EE in an SCI mouse model. Mice with spinal cord contusion were divided into two groups: those housed in standard cages (control) and those in EE conditions (EE). Each group was housed separately for either 2- or 8-weeks post-injury, after which RNA sequencing was performed and compared to a sham group (receiving only a dorsal laminectomy). The synaptic vesicle cycle (SVC) pathway and related genes showed significant downregulation after SCI at both time points. Subsequently, we investigated whether exposure to EE for 2- and 8-weeks post-SCI could modulate the SVC pathway and its related genes. Notably, exposure to EE for 8 weeks resulted in a marked reversal effect of SVC-related gene expression, along with stimulation of axon regeneration and mitigation of locomotor activity loss. Thus, prolonged exposure to EE increased presynaptic activity, fostering axon regeneration and functional improvement by modulating the SVC in the SCI mouse model. These findings suggest that EE exposure proves effective in inducing activity-dependent plasticity, offering a promising therapeutic approach akin to rehabilitation training in patients with SCI.

Effects of a Combination of Polynucleotide and Hyaluronic Acid for Treating Osteoarthritis

Knee osteoarthritis (OA), an age-related degenerative disease characterized by severe pain and disability, is treated using polynucleotides (PNs) and hyaluronic acid (HA). The intra-articular (IA) injection of HA has been studied extensively in both animal models and in humans; however, the efficacy and mechanisms of action remain unclear. In addition, there has been a paucity of research regarding the use of PN alone or in combination with HA in OA. To investigate the effect of the combined injection of PN and HA in vivo, pathological and behavioral changes were assessed in an OA model. Anterior cruciate ligament transection and medial meniscectomy were performed in Sprague-Dawley rats to create the OA animal model. The locomotor activity improved following PNHA injection, while the OARSI grade improved in the medial tibia and femur. In mild OA, TNFα levels decreased histologically in the PN, HA, and PNHA groups but only the PNHA group showed behavioral improvement in terms of distance. In conclusion, PNHA exhibited anti-inflammatory effects during OA progression and improved locomotor activity regardless of the OARSI grade.

Polynucleotides Suppress Inflammation and Stimulate Matrix Synthesis in an In Vitro Cell-Based Osteoarthritis Model

Osteoarthritis (OA) is characterized by degeneration of the joint cartilage, inflammation, and a change in the chondrocyte phenotype. Inflammation also promotes cell hypertrophy in human articular chondrocytes (HC-a) by activating the NF-κB pathway. Chondrocyte hypertrophy and inflammation promote extracellular matrix degradation (ECM). Chondrocytes depend on Smad signaling to control and regulate cell hypertrophy as well as to maintain the ECM. The involvement of these two pathways is crucial for preserving the homeostasis of articular cartilage. In recent years, Polynucleotides Highly Purified Technology (PN-HPT) has emerged as a promising area of research for the treatment of OA. PN-HPT involves the use of polynucleotide-based agents with controlled natural origins and high purification levels. In this study, we focused on evaluating the efficacy of a specific polynucleotide sodium agent, known as CONJURAN, which is derived from fish sperm. Polynucleotides (PN), which are physiologically present in the matrix and function as water-soluble nucleic acids with a gel-like property, have been used to treat patients with OA. However, the specific mechanisms underlying the effect remain unclear. Therefore, we investigated the effect of PN in an OA cell model in which HC-a cells were stimulated with interleukin-1β (IL-1β) with or without PN treatment. The CCK-8 assay was used to assess the cytotoxic effects of PN. Furthermore, the enzyme-linked immunosorbent assay was utilized to detect MMP13 levels, and the nitric oxide assay was utilized to determine the effect of PN on inflammation. The anti-inflammatory effects of PN and related mechanisms were investigated using quantitative PCR, Western blot analysis, and immunofluorescence to examine and analyze relative markers. PN inhibited IL-1β induced destruction of genes and proteins by downregulating the expression of MMP3, MMP13, iNOS, and COX-2 while increasing the expression of aggrecan (ACAN) and collagen II (COL2A1). This study demonstrates, for the first time, that PN exerted anti-inflammatory effects by partially inhibiting the NF-κB pathway and increasing the Smad2/3 pathway. Based on our findings, PN can potentially serve as a treatment for OA.

Therapeutic effects of polydeoxyribonucleotide in an in vitro neuronal model of ischemia/reperfusion injury

Polydeoxyribonucleotide (PDRN) is an agonist that selectively stimulates adenosine A_2A receptor (ADORA2A), which suppresses inflammatory responses. Ischemia/reperfusion (I/R) injury plays a major role in the pathogenesis of ischemic stroke by inducing neuroinflammation. Therefore, this study aimed to investigate the therapeutic effects of PDRN in an in vitro I/R injury model. The in vitro model was established with differentiated Neuro-2a cells under oxygen and glucose deprivation condition. The cells were treated with PDRN for 24 h under reoxygenation condition. As the results of RNA-seq transcriptome analysis, CSF1, IL-6, PTPN6, RAC2, and STAT1 were identified of its relation to the effect of PDRN on inflammatory responses in the model. To further investigate therapeutic effects of PDRN, RT-qPCR, western blotting, LDH assay, and TUNEL assay were performed. PDRN significantly reversed the expression of genes and proteins related to inflammatory responses. The elevated ADORA2A expression by PDRN treatment downregulated JAK/STAT pathway in the model. Furthermore, PDRN inhibited neuronal cell death in the model. Consequently, our results suggested that PDRN alleviated inflammatory responses through inhibition of JAK/STAT pathway by mediating ADORA2A expression and inhibited neuronal cell death in the model. These results provide significant insights into potential therapeutic approaches involving PDRN treatment for I/R injury.

The roles of nucleotide signaling and platelets in inflammation

Nucleotides and platelets have been associated with a wide range of activities that affect the host inflammatory response. The main goal of this study is to examine the roles of nucleotide signaling and platelets in inflammation. The study analysis entailed conducting a systematic search to identify relevant articles in PsycINFO, PubMed, Web of Science, and CINAHL. The evidence gathered from the identified articles shows the roles of nucleotides and platelets in inflammation. In the extracellular environment, nucleotides act as signaling molecules that can activate nucleotide receptors to promote inflammation. Inflammation is an essential process through which the innate immune system responds to pathogens, microbes, and damage-associated molecular patterns. Moreover, research evidence shows that the mechanisms through which platelets affect inflammatory responses and regulate hemostasis are the same. The roles of nucleotides and platelets in inflammation have been explored in several studies worldwide. Although platelets and nucleotides have unique structures, both of them influence the host response to pathogens and tumors. Analysis of platelets and nucleotides will offer valuable insight for the development of new treatments for infectious and inflammatory diseases.

Study of the Efficacy of Artificial Intelligence Algorithm-Based Analysis of the Functional and Anatomical Improvement in Polynucleotide Treatment in Knee Osteoarthritis Patients: A Prospective Case Series

Knee osteoarthritis (OA) is one of the most common degenerative diseases in old age. Recent studies have suggested new treatment approaches dealing with subchondral remodeling, which is a typical feature of OA progression. However, diagnostic tools or therapeutic approaches related to such a process are still being researched. The automated artificial intelligence (AI) algorithm-based texture analysis is a new method used for OA-progression detection. We designed a prospective case series study to examine the efficacy of the AI algorithm-based texture analysis in detecting the restoration of the subchondral remodeling process, which is expected to follow therapeutic intervention. In this study, we used polynucleotide (PN) filler injections as the therapeutic modality and the treatment outcome was verified by symptom improvement, as well as by the induction of subchondral microstructural changes. We used AI algorithm-based texture analysis to observe these changes in the subchondral bone with the bone structure value (BSV). A total of 51 participants diagnosed with knee OA were enrolled in this study. Intra-articular PN filler (HP cell Vitaran J) injections were administered once a week and five times in total. Knee X-rays and texture analyses with BSVs were performed during the screening visit and the last visit three months after screening. The Visual Analogue Scale (VAS) and Korean-Western Ontario MacMaster (K-WOMAC) measurements were used at the screening visit, the fifth intra-articular injection visit, and the last visit. The VAS and K-WOMAC scores decreased after PN treatment and lasted for three months after the final injection. The BSV changed in the middle and deep layers of tibial bone after PN injection. This result could imply that there were microstructural changes in the subchondral bone after PN treatment, and that this change could be detected using the AI algorithm-based texture analysis. In conclusion, the AI- algorithm-based texture analysis could be a promising tool for detecting and assessing the therapeutic outcome in knee OA.

Applications of Marine Organism-Derived Polydeoxyribonucleotide: Its Potential in Biomedical Engineering

Polydeoxyribonucleotides (PDRNs) are a family of DNA-derived drugs with a molecular weight ranging from 50 to 1500 kDa, which are mainly extracted from the sperm cells of salmon trout or chum salmon. Many pre-clinical and clinical studies have demonstrated the wound healing and anti-inflammatory properties of PDRN, which are mediated by the activation of adenosine A2A receptor and salvage pathways, in addition to promoting osteoblast activity, collagen synthesis, and angiogenesis. In fact, PDRN is already marketed due to its therapeutic properties against various wound healing- and inflammation-related diseases. Therefore, this review assessed the most recent trends in marine organism-derived PDRN using the Google Scholar search engine. Further, we summarized the current applications and pharmacological properties of PDRN to serve as a reference for the development of novel PDRN-based technologies.

3'-Sialyllactose Protects SW1353 Chondrocytic Cells From Interleukin-1β-Induced Oxidative Stress and Inflammation

Osteoarthritis (OA) is a major degenerative joint disease. Oxidative stress and inflammation play key roles in the pathogenesis of OA. 3'-Sialyllactose (3'-SL) is derived from human milk and is known to regulate a variety of biological functions related to immune homeostasis. This study aimed to investigate the therapeutic mechanisms of 3'-SL in interleukin-1β (IL-1β)-treated SW1353 chondrocytic cells. 3'-SL potently suppressed IL-1β-induced oxidative stress by increasing the levels of enzymatic antioxidants. 3'-SL significantly reversed the IL-1β mediated expression levels of reactive oxygen species in IL-1β-stimulated chondrocytic cells. In addition, 3'-SL could reverse the increased levels of inflammatory markers such as nitrite, prostaglandin E2, inducible nitric oxide synthase, cyclooxygenase-2, IL-1β, and IL-6 in IL-1β-stimulated chondrocytic cells. Moreover, 3'-SL significantly inhibited the apoptotic process, as indicated by the downregulation of the pro-apoptotic protein Bax, upregulation of the anti-apoptotic protein Bcl-2 expression, and significant reduction in the number of TUNEL-positive cells in the IL-1β-treated chondrocytic cells. Furthermore, 3'-SL reversed cartilage destruction by decreasing the release of matrix metalloproteinases (MMP), such as MMP1, MMP3, and MMP13. In contrast, 3'-SL significantly increased the expression levels of matrix synthesis proteins, such as collagen II and aggrecan, in IL-1β-treated chondrocytic cells. 3'-SL dramatically suppressed the activation of mitogen-activated protein kinases (MAPK) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways, which are related to the pathogenesis of OA. Taken together, our data suggest that 3'-SL alleviates IL-1β-induced OA pathogenesis via inhibition of activated MAPK and PI3K/AKT/NF-κB signaling cascades with the downregulation of oxidative stress and inflammation. Therefore, 3'-SL has the potential to be used as a natural compound for OA therapy owing to its ability to activate the antioxidant defense system and suppress inflammatory responses.

Activation of G-protein-coupled bile acid receptor Gpbar1 (TGR5) inhibits degradation of type II collagen and aggrecan in human chondrocytes

Abnormal loss of components of the extracellular matrix (ECM) including type II collagen and aggrecan caused by proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) is an important pathophysiological characteristic of osteoarthritis (OA). G-protein-coupled bile acid receptor, Gpbar1 (TGR5), is an important member of the bile acid receptor subclass of G Protein-Coupled Receptors (GPCRs). Little information regarding the effects of TGR5 in the pathological development of OA has been reported before. In the current study, we showed that TGR5 is expressed in human primary chondrocytes and human chondrosarcoma SW1353 cells. Interestingly, expression of TGR5 was reduced in response to TNF-α treatment in SW1353 cells. Our results indicate that activation of TGR5 using its specific agonist INT-777 reduced TNF-α-induced degradation of the articular ECM, including type II collagen and aggrecan, by inhibiting expression of matrix metalloproteinase-3 (MMP-3), MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs- 4 (ADAMTS-4) and ADAMTS-5. We also found that INT-777 treatment inhibited phosphorylation of p38 and activation of the IκB kinase/inhibitory κBα/nuclear factor- κB (IKK/IκBα/NF-κB) signaling pathway. Notably, knockdown of TGR5 abolished the protective effects of INT-777 against ECM degradation, suggesting the involvement of TGR5. Our findings implicate that TGR5 might be considered as a potential therapeutic target for the treatment of OA.

Effect of Polydeoxyribonucleotide on Angiogenesis and Wound Healing in an In Vitro Model of Osteoarthritis

Osteoarthritis (OA) is degenerative disease, leading to pain and functional disability. It is reported that polydeoxyribonucleotide (PDRN) is a suitable therapy for OA. However, the therapeutic mechanisms of PDRN in OA are not fully understood. To investigate the effect of PDRN in an in vitro model of OA, interleukin (IL)-1β or phosphate-buffered saline (PBS) was used to treat a human chondrocytic cell line in hypoxic conditions for 24 h (IL-1β group or control group). PDRN was then used to treat IL-1β group cells for 24 h (PDRN group). By Label-Based Human Antibody Array 1000, angiopoietin-2 (ANG-2), platelet-derived growth factor (PDGF), angiostatin, and endostatin, which were related to angiogenesis, were chosen for further validation studies. Quantitative real-time reverse transcription polymerase chain reaction and western blot analysis validated that the levels of PDGF and ANG-2, which were related to pro-angiogenesis, were significantly increased in the PDRN group compared with those in the control group or the IL-1β group. However, the levels of endostatin and angiostatin, which were related in anti-angiogenesis, were significantly decreased in the PDRN group compared with those in the control group or the IL-1β group. In the same manner, vascular endothelial growth factor, which was a mediator of angiogenesis, was significantly increased in the PDRN group compared with those in the control group or the IL-1β group. Furthermore, wound closure was significantly increased in the PDRN group compared with the control group or the IL-1β group by in vitro scratch assay. Moreover, PDRN decreased expression of metalloproteinase 13, as a catabolic factor for OA, but increased expression of aggrecan, which was an anabolic factor for OA. These data suggest that PDRN may promote angiogenesis and wound healing via down-regulation of catabolism and up-regulation of anabolism in an in vitro model of OA.

High-Frequency Repetitive Magnetic Stimulation Enhances the Expression of Brain-Derived Neurotrophic Factor Through Activation of Ca2+-Calmodulin-Dependent Protein Kinase II-cAMP-Response Element-Binding Protein Pathway

Repetitive transcranial magnetic stimulation (rTMS) can be used in various neurological disorders. However, neurobiological mechanism of rTMS is not well known. Therefore, in this study, we examined the global gene expression patterns depending on different frequencies of repetitive magnetic stimulation (rMS) in both undifferentiated and differentiated Neuro-2a cells to generate a comprehensive view of the biological mechanisms. The Neuro-2a cells were randomly divided into three groups—the sham (no active stimulation) group, the low-frequency (0.5 Hz stimulation) group, and high-frequency (10 Hz stimulation) group—and were stimulated 10 min for 3 days. The low- and high-frequency groups of rMS on Neuro-2a cells were characterized by transcriptome array. Differentially expressed genes were analyzed using the Database of Annotation Visualization and Integrated Discovery program, which yielded a Kyoto Encyclopedia of Genes and Genomes pathway. Amphetamine addiction pathway, circadian entrainment pathway, long-term potentiation (LTP) pathway, neurotrophin signaling pathway, prolactin signaling pathway, and cholinergic synapse pathway were significantly enriched in high-frequency group compared with low-frequency group. Among these pathways, LTP pathway is relevant to rMS, thus the genes that were involved in LTP pathway were validated by quantitative real-time polymerase chain reaction and western blotting. The expression of glutamate ionotropic receptor N-methyl d-aspartate 1, calmodulin-dependent protein kinase II (CaMKII) δ, and CaMKIIα was increased, and the expression of CaMKIIγ was decreased in high-frequency group. These genes can activate the calcium (Ca²⁺)–CaMKII–cAMP-response element-binding protein (CREB) pathway. Furthermore, high-frequency rMS induced phosphorylation of CREB, brain-derived neurotrophic factor (BDNF) transcription via activation of Ca²⁺–CaMKII–CREB pathway. In conclusion, high-frequency rMS enhances the expression of BDNF by activating Ca²⁺–CaMKII–CREB pathway in the Neuro-2a cells. These findings may help clarify further therapeutic mechanisms of rTMS.