Adenosine A2A receptor agonist polydeoxyribonucleotide ameliorates short-term memory impairment by suppressing cerebral ischemia-induced inflammation via MAPK pathway

Polydeoxyribonucleotides Pre-Clinical Findings in Bone Healing: A Scoping Review

AIM

Polydeoxyribonucleotide (PDRN) is a chain-like polymer derived from DNA. Recent in vitro and animal studies have showcased the beneficial impacts of PDRN on the process of bone mending, whether used on its own or in conjunction with other substances that aid in regeneration. This scoping review aims to synthesize the current understanding of how PDRNs influence bone healing.

MATERIALS AND METHODS

The studies included in the screening procedure were randomized controlled clinical trials (RCTs), both retrospective and prospective case-control studies, as well as in vitro and in vivo investigations. Articles were sourced from PubMed (MEDLINE), Scopus, EMBASE, Web of Science, and Google Scholar electronic databases using the following MeSH terms: (polydeoxyribonucleotide) and (bone) and (regeneration).

RESULTS

Initially, 228 articles were identified. Following the review process, a total of eight studies were ultimately examined. Among these, two were confined to laboratory studies, five were conducted on living organisms, and one encompassed both evaluations on living organisms and in vitro assessments. A descriptive qualitative approach was employed to present the data extracted from the studies that were included.

CONCLUSIONS

PDRN has the potential to enhance the process of bone healing and the quantity of newly generated bone when combined with grafting materials. Future clinical studies are warranted to ascertain the appropriate clinical application of PDRN based on the dosage under consideration.

Neuroprotective effect of Potentilla reptans L. root in the rat brain global ischemia/reperfusion model

Stroke is the most common cause of death among neurological diseases. The protective effects of Potentilla reptans L. include antioxidative, anti-inflammatory, and antiapoptotic effects. In this study, the brain protection and beta-amyloid effects of P. reptans root extract were investigated in the rat brain ischemia/reperfusion (IR) model. Forty male Wistar rats were randomly divided into five groups (n = 8), including IR, sham, and three groups receiving P. reptans with concentrations of 0.025, 0.05, and 0.1 (g/kg/b.w.), which were injected daily for 7 days. For the IR model, the common carotid artery was occluded bilaterally for 8 min. All injections were intraperitoneal (IP). The shuttle box test was used to measure passive avoidance memory. Then the brain tissue was extracted for the histological examination of neuron counts and β-amyloid plaques using a morphometric technique, and finally, Statistical Package for the Social Sciences software was used for statistical analysis of the data. Pretreatment with P. reptans improved memory impairment. Also, by examining the tissues of the CA1, CA3, and dentate gyrus areas of the hippocampus, it was observed that the number of plaques in the groups receiving P. reptans extract was reduced compared to the IR group, especially at the concentration of 0.05 g/kg/b.w. Also, P. reptans improved the number of neurons at all concentrations, in which the concentration of 0.05 g/kg/b.w. showed more effective therapeutic results. Taken together, we found that P. reptans root extract has beneficial effects on memory impairment, neuronal loss, and β-amyloid accumulation.

Analysis of Skin Regeneration and Barrier-Improvement Efficacy of Polydeoxyribonucleotide Isolated from Panax Ginseng (C.A. Mey.) Adventitious Root

Polydeoxyribonucleotide (PDRN) has the ability to regenerate skin cells and improve the skin barrier and wound healing. This study investigated the possibility of replacing animal-derived PDRN with plant-derived PDRN. To test this, the adventitious roots of Korean ginseng (Panax ginseng C.A. Meyer), which is commonly used to treat various diseases, were suspension-cultivated through tissue culture; subsequently, PDRN was purified using microfluidization, an ultra-high-pressure physical grinding method. The results showed that purified Panax PDRN was effective in healing skin wounds and enhancing the skin barrier. Panax PDRN promoted the proliferation of keratinocytes and fibroblasts by increasing the expression of fibronectin, filaggrin, Ki-67, Bcl-2, inhibin beta A, and Cyclin D1. It also acted as an agonist of the adenosine A2A receptor and induced the phosphorylation of focal adhesion kinase, adenosine triphosphate-dependent tyrosine kinase, and mitogen-activated protein kinase. This activated signal transduction, thereby regenerating skin cells and strengthening the barrier. These results were not only observed in skin cells but also in an artificial skin model (KeraSkinTM). The use of plant-derived PDRN instead of animal-derived PDRN can promote animal welfare and environmental sustainability. Furthermore, Panax PDRN can potentially be a new plant-derived PDRN (PhytoPDRN) that may be utilized in the treatment of various skin diseases.

3D-Printed Functional Hydrogel by DNA-Induced Biomineralization for Accelerated Diabetic Wound Healing

Chronic wounds in diabetic patients are challenging because their prolonged inflammation makes healing difficult, thus burdening patients, society, and health care systems. Customized dressing materials are needed to effectively treat such wounds that vary in shape and depth. The continuous development of 3D-printing technology along with artificial intelligence has increased the precision, versatility, and compatibility of various materials, thus providing the considerable potential to meet the abovementioned needs. Herein, functional 3D-printing inks comprising DNA from salmon sperm and DNA-induced biosilica inspired by marine sponges, are developed for the machine learning-based 3D-printing of wound dressings. The DNA and biomineralized silica are incorporated into hydrogel inks in a fast, facile manner. The 3D-printed wound dressing thus generates provided appropriate porosity, characterized by effective exudate and blood absorption at wound sites, and mechanical tunability indicated by good shape fidelity and printability during optimized 3D printing. Moreover, the DNA and biomineralized silica act as nanotherapeutics, enhancing the biological activity of the dressings in terms of reactive oxygen species scavenging, angiogenesis, and anti-inflammation activity, thereby accelerating acute and diabetic wound healing. These bioinspired 3D-printed hydrogels produce using a DNA-induced biomineralization strategy are an excellent functional platform for clinical applications in acute and chronic wound repair.

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.

Mitochondrial pyruvate carrier 1 alleviates hypoxic-ischemic brain injury in rats

AIMS

Mitochondrial dysfunction is a critical pathological change in cerebral ischemia. Mitochondrial pyruvate carrier 1 (MPC1) is a mitochondrial inner membrane protein carrier participating in pyruvate transport. The work is aiming to figure out the effect of MPC1 on cerebral ischemia.

MAIN METHODS

Bilateral internal carotid artery embolization (BICAO) rats model and cells model from oxygen glucose deprivation/reoxygenation (OGD/R) were used to simulate cerebral ischemia in vivo and in vitro. The effect of MPC1 on cerebral ischemia was detected by imaging, behavioral test, immunofluorescence, flow cytometry, transmission electron microscopy, Western blot and RT-Q-PCR. RNA-sequence (RNA-seq) was applied to explore the potential molecular mechanisms underlying the role of MPC1 in cerebral ischemia.

KEY FINDING

After BICAO or OGD/R treatment, MPC1 expression in ischemic cortical neurons was significantly decreased, and MPC1 deficiency significantly reduced cerebral blood flow, decreased locomotion activities, and exacerbated neuronal injury. Moreover, MPC1 deficiency obviously aggravated oxidative stress, structural disruption and dysfunction of mitochondria, autophagy and calcium overload of ischemic cortical neurons. Interestingly, MPC1 overexpression remarkably reversed neuronal loss and persisting neuronal deficits induced by OGD. Using RNA-seq, 38 MPC1-associated differentially expressed genes were involved in oxidative stress, autophagy and calcium overload. Our results further confirmed that MPC1 could alleviate autophagy via the PI3K/Akt/mTOR pathway in the ischemic cortical neurons.

SIGNIFICANCE

MPC1 may exert neuroprotective effects by attenuating oxidative stress, mitochondrial dysfunction, calcium overload and autophagy during cerebral ischemia. MPC1-related genes identified by RNA-seq may be a novel therapeutic target for cerebral ischemia.

Neuroprotective Effects of Ethanol Extract of Polyscias fruticosa (EEPF) against Glutamate-Mediated Neuronal Toxicity in HT22 Cells

In traditional herbal medicine, the Polyscias fruticosa has been frequently used for the treatment of ischemia and inflammation. Oxidative stress mediated by elevated glutamate levels cause neuronal cell death in ischemia and various neurodegenerative diseases. However, so far, the neuroprotective effects of this plant extract against glutamate-mediated cell death have not been investigated in cell models. The current study investigates the neuroprotective effects of ethanol extracts of Polyscias fruticosa (EEPF) and elucidates the underlying molecular mechanisms of EEPFs relevant to neuroprotection against glutamate-mediated cell death. The oxidative stress-mediated cell death was induced by 5 mM glutamate treatment in HT22 cells. The cell viability was measured by a tetrazolium-based EZ-Cytox reagent and Calcein-AM fluorescent dye. Intracellular Ca²⁺ and ROS levels were measured by fluorescent dyes, fluo-3 AM and 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA), respectively. Protein expressions of p-AKT, BDNF, p-CREB, Bax, Bcl-2, and apoptosis-inducing factor (AIF) were determined by western blot analysis. The apoptotic cell death was measured by flow cytometry. The in vivo efficacy of EEPF was evaluated using the Mongolian gerbil mouse by surgery-induced brain ischemia. EEPF treatment showed a neuroprotective effect against glutamate-induced cell death. The EEPF co-treatment reduced the intracellular Ca²⁺ and ROS and apoptotic cell death. Furthermore, it recovered the p-AKT, p-CREB, BDNF, and Bcl-2 levels decreased by glutamate. The EEPF co-treatment suppressed the activation of apoptotic Bax, the nuclear translocation of AIF, and mitogen-activated protein kinase (MAPK) pathway proteins (ERK1/2, p38, JNK). Further, EEPF treatment significantly rescued the degenerative neurons in the ischemia-induced Mongolian gerbil in vivo model. EEPF exhibited neuroprotective properties that suppress glutamate-mediated neurotoxicity. The underlying mechanism of EEPF is increasing the level of p-AKT, p-CREB, BDNF, and Bcl-2 associated with cell survival. It has therapeutic potential for the treatment of glutamate-mediated neuropathology.

Polydeoxyribonucleotide ameliorates alcoholic liver injury though suppressing phosphatidylinositol 3-kinase/protein kinase B signaling pathway in mice

Polydeoxyribonucleotide (PDRN), which is adenosine A_2A receptor agonist, facilitates healing and inhibits inflammation and apoptosis. The effect of PDRN on alcoholic liver injury (ALI) was evaluated focusing on the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. The mice were given daily oral administration of 50% ethanol at a dose of 4 g/kg during 8 weeks. After 4 weeks of alcohol intake, 200 μL of normal saline containing 8-mg/kg PDRN was intraperitoneally administered 3 times a week for 4 weeks. To determine whether the action of PDRN occurs through the adenosine A_2A receptor, 8-mg/kg 3,7-dimethyl-1-propargylxanthine (DMPX) with PDRN was treated. The concentration of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) was detected. For liver histopathological score, hematoxylin and eosin staining was conducted. Enzyme-linked immunoassay was used to measure cyclic adenosine-3',5'-monophosphate (cAMP) concentration. PI3K and Akt expression was determined using Western blot analysis. In the results, PDRN treatment suppressed AST and ALT level in serum and liver tissue, and improved damaged liver tissue and decreased histological score. PDRN application inhibited the expression of phosphorylated PI3K/Akt signaling pathway. The increasing effect of PDRN on cAMP level ats as a mechanism for ALI treatment. Co-treatment of DMPX with PDRN did not reduce apoptosis, causing no improvement in liver function. As a result of this experiment, PDRN has the potential to be selected as a therapeutic agent for ALI.

Regulating DNA methylation could reduce neuronal ischemia response and apoptosis after ischemia-reperfusion injury

BACKGROUND

Ischemia-reperfusion injury (IRI) is an important pathophysiological condition that can cause cell injury and large-scale tissue injury in the nervous system. Previous studies have shown that epigenetic regulation may play a role in the pathogenesis of IRI.

METHODS

In this study, we isolated mouse cortical neurons and constructed an oxygen-glucose deprivation/reoxygenation (OGD) model to explore the change in DNA methylation and its effect on the expression of corresponding genes.

RESULTS

We found that DNA methylation in neurons increased with hypoxia duration and that hypermethylation of numerous promoters and 3'-untranslated regions increased. We performed Gene Ontology enrichment analysis to study gene function and Kyoto Encyclopedia of Genes and Genomes pathway analysis to identify the pathways associated with gene regulation. The results showed that hypermethylation-related genes expressed after OGD were related to physiological pathways such as neuronal projection, ion transport, growth and development, while hypomethylation-related genes were related to pathological pathways such as the external apoptosis signaling pathway, neuronal death regulation, and regulation of oxidative stress. However, the changes in DNA methylation were specific for certain genes and may have been related to OGD-induced neuronal damage. Importantly, we integrated transcription and DNA methylation data to identify several candidate target genes, including hypomethylated Apoe, Pax6, Bmp4, and Ptch1 and hypermethylated Adora2a, Crhr1, Stxbp1, and Tac1. This study further indicated the effect of DNA methylation on gene function in brain IRI from the perspective of epigenetics, and the identified genes may become new targets for achieving neuroprotection in the brain after IRI.

Beneficial Effects of Polydeoxyribonucleotide (PDRN) in an In Vitro Model of Fuchs Endothelial Corneal Dystrophy

Fuchs endothelial corneal dystrophy (FECD) is a bilateral, hereditary syndrome characterized by progressive irreversible injury in the corneal endothelium; it is the most frequent cause for corneal transplantation worldwide. Oxidative stress induces the apoptosis of corneal endothelial cells (CECs), and has a crucial function in FECD pathogenesis. The stimulation of the adenosine A_2A receptor (A_2Ar) inhibits oxidative stress, reduces inflammation and modulates apoptosis. Polydeoxyribonucleotide (PDRN) is a registered drug that acts through adenosine A_2Ar. Thus, the goal of this study was to assess the effect of PDRN in an in vitro FECD model. Human Corneal Endothelial Cells (IHCE) were challenged with H₂O₂ (200 μM) alone or in combination with PDRN (100 μg/mL), PDRN plus ZM241385 (1 μM) as an A_2Ar antagonist, and CGS21680 (1 μM) as a well-known A_2Ar agonist. H₂O₂ reduced the cells’ viability and increased the expression of the pro-inflammatory markers NF-κB, IL-6, IL-1β, and TNF-α; by contrast, it decreased the expression of the anti-inflammatory IL-10. Moreover, the pro-apoptotic genes Bax, Caspase-3 and Caspase-8 were concurrently upregulated with a decrease of Bcl-2 expression. PDRN and CGS21680 reverted the negative effects of H₂O₂. Co-incubation with ZM241385 abolished the effects of PDRN, indicating that A_2Ar is involved in the mode of action of PDRN. These data suggest that PDRN defends IHCE cells against H₂O₂-induced damage, potentially as a result of its antioxidant, anti-inflammatory and antiapoptotic properties, suggesting that PDRN could be used as an FECD therapy.

Neuroprotective Effects of Purpurin Against Ischemic Damage via MAPKs, Bax, and Oxidative Stress Cascades in the Gerbil Hippocampus

Purpurin has various effects, including anti-inflammatory effects, and can efficiently cross the blood-brain barrier. In the present study, we investigated the effects of purpurin on oxidative stress in HT22 cells and mild brain damage in the gerbil hippocampal CA1 region induced by transient forebrain ischemia. Oxidative stress induced by H2O2 was significantly ameliorated by treatment with purpurin, based on changes in cell death, DNA fragmentation, formation of reactive oxygen species, and pro-apoptotic (Bax)/anti-apoptotic (Bcl-2) protein levels. In addition, treatment with purpurin significantly reduced the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK), and p38 signaling in HT22 cells. Transient forebrain ischemia in gerbils led to a significant increase in locomotor activity 1 day after ischemia and significant decrease in number of surviving cells in the CA1 region 4 days after ischemia. Administration of purpurin reduced the travel distance 1 day after ischemia and abrogates the neuronal death in the hippocampal CA1 region 4 days after ischemia based on immunohistochemical and histochemical staining for NeuN and Fluoro-Jade C, respectively. Purpurin treatment significantly decreased the activation of microglia and astrocytes as well as the increases of nuclear factor kappa-light-chain-enhancer of activated B cells p65 in the hippocampal CA1 region 4 days after ischemia and ameliorated the ischemia-induced transient increases of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in the hippocampus 6 h after ischemia. In addition, purpurin significantly alleviated the ischemia-induced phosphorylation of JNK, ERK, and p38 in the hippocampus 1 day after ischemia. Furthermore, purpurin treatment significantly mitigated the increases of Bax in the hippocampus 1 day after ischemia and the lipid peroxidation based on malondialdehyde and hydroperoxides levels 2 days after ischemia. These results suggest that purpurin can be one of the potential candidates to reduce neuronal damage and inflammatory responses after oxidative stress in HT22 cells or ischemic damage in gerbils.

Cissus verticillata Extract Decreases Neuronal Damage Induced by Oxidative Stress in HT22 Cells and Ischemia in Gerbils by Reducing the Inflammation and Phosphorylation of MAPKs

In the present study, we examined the effects of Cissus verticillata leaf extracts (CVE) against hydrogen peroxide (H₂O₂)- and ischemia-induced neuronal damage in HT22 cells and gerbil hippocampus. Incubation with CVE produced concentration-dependent toxicity in HT22 cells. Significant cellular toxicity was observed with >75 μg/mL CVE. CVE treatment at 50 μg/mL ameliorated H₂O₂-induced reactive oxygen species formation, DNA fragmentation, and cell death in HT22 cells. In addition, incubation with CVE significantly mitigated the increase in Bax and decrease in Bcl-2 induced by H₂O₂ treatment in HT22 cells. In an in vivo study, the administration of CVE to gerbils significantly decreased ischemia-induced motor activity 1 d after ischemia, as well as neuronal death and microglial activation 4 d after ischemia, respectively. CVE treatment reduced the release of interleukin-1β, interleukin-6, and tumor necrosis factor-α 6 h after ischemia. Furthermore, CVE treatment significantly ameliorated ischemia-induced phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase 1/2, and p38. These results suggest that CVE has the potential to reduce the neuronal damage induced by oxidative and ischemic stress by reducing the inflammatory responses and phosphorylation of MAPKs, suggesting that CVE could be a functional food to prevent neuronal damage induced by ischemia.