Cannabinoid-mediated Modulation of Oxidative Stress and Early Inflammatory Response after Hypoxia-Ischemia

Bone marrow mesenchymal stem cells alleviate neurological dysfunction by reducing autophagy damage via downregulation of SYNPO2 in neonatal hypoxic-ischemic encephalopathy rats

Neonatal hypoxic-ischemic encephalopathy (HIE) is worsened by autophagy-induced neuronal damage, with SYNPO2 playing a key role in this process. This study investigates the involvement of SYNPO2 in neuronal autophagy and explores the potential of bone marrow mesenchymal stem cells (BMSCs) to alleviate HIE-induced dysfunction by inhibiting SYNPO2-mediated autophagy. Using in vitro and in vivo neonatal HIE models, we observed an upregulation of SYNPO2 expression, accompanied by increased neuronal injury and aggregation of autophagy-related proteins. Intervention with BMSCs effectively reduced SYNPO2 expression, and SYNPO2 depression mitigated neuroautophagic damage and improved neurological dysfunctions. Moreover, SYNPO2 overexpression exacerbated neuroautophagy despite BMSC treatment, while SYNPO2 depletion notably reduced neuroautophagic damage and alleviated cognitive impairments, retaining the neuroprotective efficacy of BMSC treatment. These findings confirm the role of BMSCs in attenuating HIE injury by suppressing neuroautophagy and provide insights into the mechanistic involvement of SYNPO2. Ultimately, this study identifies SYNPO2 as a novel therapeutic target for neonatal HIE and supports the clinical potential of BMSCs in HIE management.

The Effects of Cannabinoids on Ischemic Stroke-Associated Neuroinflammation: A Systematic Review

Stroke represents a significant burden on global health and the economy, with high mortality rates, disability, and recurrence. Ischemic stroke is a serious condition that occurs when a blood vessel in the brain is interrupted, reducing the blood supply to the affected area. Inflammation is a significant component in stroke pathophysiology. Neuroinflammation is triggered following the acute ischemic ictus, where the blood-brain barrier (BBB) breaks down, causing damage to the endothelial cells. The damage will eventually generate oxidative stress, activate the pathological phenotypes of astrocytes and microglia, and lead to neuronal death in the neurovascular unit. As a result, the brain unleashes a robust neuroinflammatory response, which can further worsen the neurological outcomes. Neuroinflammation is a complex pathological process involved in ischemic damage and repair. Finding new neuroinflammation molecular targets is essential to develop effective and safe novel treatment approaches against ischemic stroke. Accumulating studies have investigated the pharmacological properties of cannabinoids (CBs) for many years, and recent research has shown their potential therapeutic use in treating ischemic stroke in rodent models. These findings revealed promising impacts of CBs in reducing neuroinflammation and cellular death and ameliorating neurological deficits. In this review, we explore the possibility of the therapeutic administration of CBs in mitigating neuroinflammation caused by a stroke. We summarize the results from several preclinical studies evaluating the efficacy of CBs anti-inflammatory interventions in ischemic stroke. Although convincing preclinical evidence implies that CBs targeting neuroinflammation are promising for ischemic stroke, translating these findings into the clinical setting has proven to be challenging. The translation hurdle is due to the essence of the CBs ability to cause anxiety, cognitive deficit, and psychosis. Future studies are warranted to address the dose-beneficial effect of CBs in clinical trials of ischemic stroke-related neuroinflammation treatment.

Physiological and Genetic Basis of High-Altitude Indigenous Animals' Adaptation to Hypoxic Environments

Adaptation is one of the fundamental characteristics of life activities; humans and animals inhabiting high altitudes are well adapted to hypobaric hypoxic environments, and studies on the mechanisms of this adaptation emerged a hundred years ago. Based on these studies, this paper reviews the adaptive changes in hypoxia-sensitive tissues and organs, as well as at the molecular genetic level, such as pulmonary, cardiovascular, O2-consuming tissues, and the hemoglobin and HIF pathway, that occur in animals in response to the challenge of hypobaric hypoxia. High-altitude hypoxia adaptation may be due to the coordinated action of genetic variants in multiple genes and, as a result, adaptive changes in multiple tissues and organs at the physiological and biochemical levels. Unraveling their mechanisms of action can provide a reference for the prevention and treatment of multiple diseases caused by chronic hypoxia.

MicroRNA-124 negatively regulates STAT3 to alleviate hypoxic-ischemic brain damage by inhibiting oxidative stress

MicroRNA-124 (miR-124) is implicated in various neurological diseases; however, its significance in hypoxic-ischaemic brain damage (HIBD) remains unclear. This study aimed to elucidate the underlying pathophysiological mechanisms of miR-124 in HIBD. In our study performed on oxygen-glucose deprivation followed by reperfusion (OGD)/R-induced primary cortical neurons, a substantial reduction in miR-124 was observed. Furthermore, the upregulation of miR-124 significantly mitigated oxidative stress, apoptosis, and mitochondrial impairment. We demonstrated that miR-124 interacts with the signal transducer and activator of transcription 3 (STAT3) to exert its biological function using the dual-luciferase reporter gene assay. As the duration of OGD increased, miR-124 exhibited a negative correlation with STAT3. STAT3 overexpression notably attenuated the protective effects of miR-124 mimics, while knockdown of STAT3 reversed the adverse effects of the miR-124 inhibitor. Subsequently, we conducted an HIBD model in rats. In vivo experiments, miR-124 overexpression attenuated cerebral infarction volume, cerebral edema, apoptosis, oxidative stress, and improved neurological function recovery in HIBD rats. In summary, the neuroprotective effects of the miR-124/STAT3 axis were confirmed in the HIBD model. MiR-124 may serve as a potential biomarker with significant therapeutic implications for HIBD.

Cannabinoid Receptor Agonist WIN55, 212-2 Attenuates Injury in the Hippocampus of Rats after Deep Hypothermic Circulatory Arrest

OBJECTIVES

Postoperative neurological deficits remain a challenge in cardiac surgery employing deep hypothermic circulatory arrest (DHCA). This study aimed to investigate the effect of WIN55, 212-2, a cannabinoid agonist, on brain injury in a rat model of DHCA.

METHODS

Twenty-four male Sprague Dawley rats were randomly divided into three groups: a control group (which underwent cardiopulmonary bypass (CPB) only), a DHCA group (CPB with DHCA), and a WIN group (WIN55, 212-2 pretreatment before CPB with DHCA). Histopathological changes in the brain were evaluated by hematoxylin-eosin staining. Plasma levels of superoxide dismutase (SOD) and proinflammatory cytokines including interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-a) were determined using an enzyme-linked immunosorbent assay (ELISA). The expression of SOD in the hippocampus was detected by Western blot and immunofluorescence staining. Levels of apoptotic-related protein caspase-3 and type 1 cannabinoid receptor (CB1R) in the hippocampus were evaluated by Western blot.

RESULTS

WIN55, 212-2 administration attenuated histopathological injury of the hippocampus in rats undergoing DHCA, associated with lowered levels of IL-1β, IL-6, and TNF-α (p < 0.05, p < 0.001, and p < 0.01, vs. DHCA, respectively) and an increased level of SOD (p < 0.05 vs. DHCA). WIN55, 212-2 treatment also increased the content of SOD in the hippocampus. The protein expression of caspase-3 was downregulated and the expression of CB1R was upregulated in the hippocampus by WIN55, 212-2.

CONCLUSIONS

the administration of WIN55, 212-2 alleviates hippocampal injury induced by DHCA in rats by regulating intrinsic inflammatory and oxidative stress responses through a CB1R-dependent mechanism.

The Therapeutic Potential of the Endocannabinoid System in Age-Related Diseases

The endocannabinoid system (ECS) dynamically regulates many aspects of mammalian physiology. ECS has gained substantial interest since growing evidence suggests that it also plays a major role in several pathophysiological conditions due to its ability to modulate various underlying mechanisms. Furthermore, cannabinoids, as components of the cannabinoid system (CS), have proven beneficial effects such as anti-inflammatory, immunomodulatory, neuromodulatory, antioxidative, and cardioprotective effects. In this comprehensive review, we aimed to describe the complex interaction between CS and most common age-related diseases such as neuro-degenerative, oncological, skeletal, and cardiovascular disorders, together with the potential of various cannabinoids to ameliorate the progression of these disorders. Since chronic inflammation is postulated as the pillar of all the above-mentioned medical conditions, we also discuss in this paper the potential of CS to ameliorate aging-associated immune system dysregulation.

Cannabinoid Analogue WIN 55212-2 Protects Paraquat-Induced Lung Injury and Enhances Macrophage M2 Polarization

WIN 55212-2 is an endocannabinoids analogue that has been reported to have anti-inflammatory and anti-fibrosis effects on different models. In this study, we investigated the protective effects of WIN 55212-2 on paraquat (PQ)-induced poison on mice especially on lung injury. Mice were administrated with different dose of PQ and thereafter treated with 0.2 mg/kg or 1 mg/kg WIN 55212-2. The survival of mice was recorded during 4 weeks of observation. Twenty-eight days after PQ treatment, the cell population and inflammatory factors IL-6, IL-10, and TNF-α were measured in bronchoalveolar lavage fluid (BALF). Pulmonary fibrosis was evaluated by Masson staining. Our results showed that WIN 55212-2 treatment reduced PQ-induced mortality of mice in a dose dependent manner. It decreased the number of inflammation-associated cells, as well as the level of pro-inflammatory factors in BALF (P < 0.05). WIN 55212-2 increased M2 cells in BALF (P < 0.05), improved the lung histology, reduced fibrosis formation, and decreased TGF-β, α-SMA and PDGFRa expression. The protective effects of WIN 55212-2 on PQ-induced lung injury and fibrosis were associated with an increase inM2 cells and increased expressions of IL-10, CD163, and CD206, suggesting that polarization of M2 macrophages may be involved in WIN 55212-2 protective effects on PQ-induced lung injury.

Nucleoredoxin Plays a Key Role in the Maintenance of Retinal Pigmented Epithelium Differentiation

Nucleoredoxin (Nrx) belongs to the Thioredoxin protein family and functions in redox-mediated signal transduction. It contains the dithiol active site motif Cys-Pro-Pro-Cys and interacts and regulates different proteins in distinct cellular pathways. Nrx was shown to be catalytically active in the insulin assay and recent findings indicate that Nrx functions, in fact, as oxidase. Here, we have analyzed Nrx in the mammalian retina exposed to (perinatal) hypoxia-ischemia/reoxygenation, combining ex vivo and in vitro models. Our data show that Nrx regulates cell differentiation, which is important to (i) increase the number of glial cells and (ii) replenish neurons that are lost following the hypoxic insult. Nrx is essential to maintain cell morphology. These regulatory changes are related to VEGF but do not seem to be linked to the Wnt/β-catenin pathway, which is not affected by Nrx knock-down. In conclusion, our results strongly suggest that hypoxia-ischemia could lead to alterations in the organization of the retina, related to changes in RPE cell differentiation. Nrx may play an essential role in the maintenance of the RPE cell differentiation state via the regulation of VEGF release.

New possibilities for neuroprotection in neonatal hypoxic-ischemic encephalopathy

Around 0.75 million babies worldwide suffer from moderate or severe hypoxic-ischemic encephalopathy (HIE) each year resulting in around 400,000 babies with neurodevelopmental impairment. In 2010, neonatal HIE was associated with 2.4% of the total Global Burden of Disease. Therapeutic hypothermia (TH), a treatment that is now standard of care in high-income countries, provides proof of concept that strategies that aim to improve neurodevelopment are not only possible but can also be implemented to clinical practice. While TH is beneficial, neonates with moderate or severe HIE treated with TH still experience devastating complications: 48% (range: 44-53) combined death or moderate/severe disability. There is a concern that TH may not be effective in low- and middle-income countries. Therapies that further improve outcomes are desperately needed, and in high-income countries, they must be tested in conjunction with TH. We have in this review focussed on pharmacological treatment options (e.g. erythropoietin, allopurinol, melatonin, cannabidiol, exendin-4/exenatide). Erythropoietin and allopurinol show promise and are progressing towards the clinic with ongoing definitive phase 3 randomised placebo-controlled trials. However, there remain global challenges for the next decade. Conclusion: There is a need for more optimal animal models, greater industry support/sponsorship, increased use of juvenile toxicology, dose-ranging studies with pharmacokinetic-pharmacodynamic modelling, and well-designed clinical trials to avoid exposure to harmful medications or abandoning putative treatments. What is Known: • Therapeutic hypothermia is beneficial in neonatal hypoxic-ischemic encephalopathy. • Neonates with moderate or severe hypoxic-ischemic encephalopathy treated with therapeutic hypothermia still experience severe sequelae. What is New: • Erythropoietin, allopurinol, melatonin, cannabidiol, and exendin-4/exenatide show promise in conjunction with therapeutic hypothermia. • There is a need for more optimal animal models, greater industry support/sponsorship, increased use of juvenile toxicology, dose-ranging studies with pharmacokinetic-pharmacodynamic modelling, and well-designed clinical trials.

Endocannabinoid system: Role in blood cell development, neuroimmune interactions and associated disorders

The endocannabinoid system (ECS) is a complex physiological network involved in creating homeostasis and maintaining human health. Studies of the last 40 years have shown that endocannabinoids (ECs), a group of bioactive lipids, together with their set of receptors, function as one of the most important physiologic systems in human body. ECs and cannabinoid receptors (CBRs) are found throughout the body: in the brain tissues, immune cells, and in the peripheral organs and tissues as well. In recent years, ECs have emerged as key modulators of affect, neurotransmitter release, immune function, and several other physiological functions. This modulatory homoeostatic system operates in the regulation of brain activity and states of physical health and disease. In several research studies and patents the ECS has been recognised with neuro-protective properties thus it might be a target in neurodegenerative diseases. Most immune cells express these bioactive lipids and their receptors, recent data also highlight the immunomodulatory effects of endocannabinoids. Interplay of immune and nervous system has been recognized in past, recent studies suggest that ECS function as a bridge between neuronal and immune system. In several ongoing clinical trial studies, the ECS has also been placed in the anti-cancer drugs spotlight. This review summarizes the literature of cannabinoid ligands and their biosynthesis, cannabinoid receptors and their distribution, and the signaling pathways initiated by the binding of cannabinoid ligands to cannabinoid receptors. Further, this review highlights the functional role of cannabinoids and ECS in blood cell development, neuroimmune interactions and associated disorders. Moreover, we highlight the current state of knowledge of cannabinoid ligands as the mediators of neuroimmune interactions, which can be therapeutically effective for neuro-immune disorders and several diseases associated with neuroinflammation.