Parkinson's Disease: Potential Actions of Lithium by Targeting the WNT/β-Catenin Pathway, Oxidative Stress, Inflammation and Glutamatergic Pathway

SENP1 regulates intermittent hypoxia-induced microglia mediated inflammation and cognitive dysfunction via wnt/β-catenin pathway

Obstructive sleep apnea syndrome (OSAS), characterized by repeated narrow or collapse of the upper airway during sleep, resulting in periodic reductions or cessations in ventilation, consequent hypoxia, hypercapnia, increased sympathetic activity and sleep fragmentation, places a serious burden on society and health care. Intermittent hypoxia (IH), which cause central nervous system (CNS) inflammation, and ultimately lead to neuropathy, is thought to be a crucial contributor to cognitive impairment in OSAS. Wnt signaling pathway exerts an important role in the regulation of CNS disorders. Particularly, it may be involved in the regulation of neuroinflammation and cognitive dysfunction. However, its underlying mechanism remains poorly understood. Accumulating evidence demonstrated that Wnt signaling pathway may inhibited in a variety of neurological disorders. Recently studies revealed that SUMOylation was participated in the regulation of neuroinflammation. Members of Wnt/β-catenin pathway may be targets of SUMOylation. In vitro and in vivo molecular biology experiments explored the regulatory mechanism of SUMOylation on Wnt/β-catenin in IH-induced neuroinflammation and neuronal injury, which demonstrated that IH induced the SUMOylation of β-catenin, microglia mediated inflammation and neuronal damage. Moreover, SENP1 regulated the de-SUMOylation of β-catenin, triggered Wnt/β-catenin pathway, and alleviated neuroinflammation and neuronal injury, thus improving IH-related mice cognitive dysfunction.

New Advances in the Pharmacology and Toxicology of Lithium: A Neurobiologically Oriented Overview

Over the last six decades, lithium has been considered the gold standard treatment for the long-term management of bipolar disorder due to its efficacy in preventing both manic and depressive episodes as well as suicidal behaviors. Nevertheless, despite numerous observed effects on various cellular pathways and biologic systems, the precise mechanism through which lithium stabilizes mood remains elusive. Furthermore, there is recent support for the therapeutic potential of lithium in other brain diseases. This review offers a comprehensive examination of contemporary understanding and predominant theories concerning the diverse mechanisms underlying lithium's effects. These findings are based on investigations utilizing cellular and animal models of neurodegenerative and psychiatric disorders. Recent studies have provided additional support for the significance of glycogen synthase kinase-3 (GSK3) inhibition as a crucial mechanism. Furthermore, research has shed more light on the interconnections between GSK3-mediated neuroprotective, antioxidant, and neuroplasticity processes. Moreover, recent advancements in animal and human models have provided valuable insights into how lithium-induced modifications at the homeostatic synaptic plasticity level may play a pivotal role in its clinical effectiveness. We focused on findings from translational studies suggesting that lithium may interface with microRNA expression. Finally, we are exploring the repurposing potential of lithium beyond bipolar disorder. These recent findings on the therapeutic mechanisms of lithium have provided important clues toward developing predictive models of response to lithium treatment and identifying new biologic targets. SIGNIFICANCE STATEMENT: Lithium is the drug of choice for the treatment of bipolar disorder, but its mechanism of action in stabilizing mood remains elusive. This review presents the latest evidence on lithium's various mechanisms of action. Recent evidence has strengthened glycogen synthase kinase-3 (GSK3) inhibition, changes at the level of homeostatic synaptic plasticity, and regulation of microRNA expression as key mechanisms, providing an intriguing perspective that may help bridge the mechanistic gap between molecular functions and its clinical efficacy as a mood stabilizer.

Unraveling Dysregulated Cell Signaling Pathways, Genetic and Epigenetic Mysteries of Parkinson's Disease

Parkinson's disease (PD) is a prevalent and burdensome neurodegenerative disorder that has been extensively researched to understand its complex etiology, diagnosis, and treatment. The interplay between genetic and environmental factors in PD makes its pathophysiology difficult to comprehend, emphasizing the need for further investigation into genetic and epigenetic markers involved in the disease. Early diagnosis is crucial for optimal management of the disease, and the development of novel diagnostic biomarkers is ongoing. Although many efforts have been made in the field of recognition and interpretation of the mechanisms involved in the pathophysiology of the disease, the current knowledge about PD is just the tip of the iceberg. By scrutinizing genetic and epigenetic patterns underlying PD, new avenues can be opened for dissecting the pathology of the disorder, leading to more precise and efficient diagnostic and therapeutic approaches. This review emphasizes the importance of studying dysregulated cell signaling pathways and molecular processes associated with genes and epigenetic alterations in understanding PD, paving the way for the development of novel therapeutic strategies to combat this devastating disease.

Therapeutic Potential of Natural Compounds from Herbs and Nutraceuticals in Alleviating Neurological Disorders: Targeting the Wnt Signaling Pathway

As an important signaling pathway in multicellular eukaryotes, the Wnt signaling pathway participates in a variety of physiological processes. Recent studies have confirmed that the Wnt signaling pathway plays an important role in neurological disorders such as stroke, Alzheimer's disease, and Parkinson's disease. The regulation of Wnt signaling by natural compounds in herbal medicines and nutraceuticals has emerged as a potential strategy for the development of new drugs for neurological disorders. Purpose: The aim of this review is to evaluate the latest research results on the efficacy of natural compounds derived from herbs and nutraceuticals in the prevention and treatment of neurological disorders by regulating the Wnt pathway in vivo and in vitro. A manual and electronic search was performed for English articles available from PubMed, Web of Science, and ScienceDirect from the January 2010 to February 2023. Keywords used for the search engines were "natural products,″ "plant derived products,″ "Wnt+ clinical trials,″ and "Wnt+,″ and/or paired with "natural products″/″plant derived products", and "neurological disorders." A total of 22 articles were enrolled in this review, and a variety of natural compounds from herbal medicine and nutritional foods have been shown to exert therapeutic effects on neurological disorders through the Wnt pathway, including curcumin, resveratrol, and querctrin, etc. These natural products possess antioxidant, anti-inflammatory, and angiogenic properties, confer neurovascular unit and blood-brain barrier integrity protection, and affect neural stem cell differentiation, synaptic formation, and neurogenesis, to play a therapeutic role in neurological disorders. In various in vivo and in vitro studies and clinical trials, these natural compounds have been shown to be safe and tolerable with few adverse effects. Natural compounds may serve a therapeutic role in neurological disorders by regulating the Wnt pathway. This summary of the research progress of natural compounds targeting the Wnt pathway may provide new insights for the treatment of neurological disorders and potential targets for the development of new drugs.

Vinpocetine improves dyskinesia in Parkinson's disease rats by reducing oxidative stress and activating the Wnt/β-catenin signaling pathway

Parkinson's disease (PD) is the commonest neurodegenerative disorder. It reduces motor and cognitive function in patients. Vinpocetine (Vinp) has the effects of anti-inflammatory and antioxidant, and could improve cognitive function in patients. This study was aimed to investigating the therapeutic effects of Vinp on dyskinesia in a 6-Hydroxydopamine hydrobromide (6-OHDA)-induced PD rat model. We constructed a PD rat model by injecting 6-OHDA, and intervened with Vinp for 7 days. The motor function of the rats was evaluated by an open-field test and rotation test. Besides, H&E staining was applied to observe the changes of dopaminergic neurons in the striatum. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in the rat striatum were detected. We assessed the impact of Vinp on α-synuclein (α-Syn) and Wnt/β-catenin signaling pathway-related molecules by western blot and qRT-PCR. Rats in the PD group showed reduced horizontal movement frequency and number of squares crossed, increased contact time and rotation frequency, and reduced number of dopaminergic neurons accompanied by severe morphological damage. Vinp treatment increased the horizontal movement frequency and number of squares crossed, reduced the contact time, and rotation frequency in PD rats. Also, Vinp downregulated α-Syn protein expression and MDA level, while upregulated SOD activity in the striatum of PD rats. Furthermore, Vinp treatment activated the Wnt/β-catenin signaling pathway in the striatum of PD rats. In conclusion, Vinp improved the dyskinesia in 6-OHDA-induced PD rats by alleviating oxidative stress, and these effects may be associated with activating the Wnt/β-catenin signaling pathway.

Pharmacological interventions targeting the microcirculation following traumatic spinal cord injury

Traumatic spinal cord injury is a devastating disorder characterized by sensory, motor, and autonomic dysfunction that severely compromises an individual's ability to perform activities of daily living. These adverse outcomes are closely related to the complex mechanism of spinal cord injury, the limited regenerative capacity of central neurons, and the inhibitory environment formed by traumatic injury. Disruption to the microcirculation is an important pathophysiological mechanism of spinal cord injury. A number of therapeutic agents have been shown to improve the injury environment, mitigate secondary damage, and/or promote regeneration and repair. Among them, the spinal cord microcirculation has become an important target for the treatment of spinal cord injury. Drug interventions targeting the microcirculation can improve the microenvironment and promote recovery following spinal cord injury. These drugs target the structure and function of the spinal cord microcirculation and are essential for maintaining the normal function of spinal neurons, axons, and glial cells. This review discusses the pathophysiological role of spinal cord microcirculation in spinal cord injury, including its structure and histopathological changes. Further, it summarizes the progress of drug therapies targeting the spinal cord microcirculation after spinal cord injury.

The Protective Effect of Lithium Against Rotenone may be Evolutionarily Conserved: Evidence from Eisenia fetida, a Primitive Animal with a Ganglionic Brain

Chronic exposure to stress is a non-adaptive situation that is associated with mitochondrial dysfunction and the accumulation of reactive oxygen species (ROS), especially superoxide anion (SA). This accumulation of ROS produces damage-associated molecular patterns (DAMPs), which activate chronic inflammatory states and behavioral changes found in several mood disorders. In a previous study, we observed that an imbalance of SA triggered by rotenone (Ro) exposure caused evolutionarily conserved oxi-inflammatory disturbances and behavioral changes in Eisenia fetida earthworms. These results supported our hypothesis that SA imbalance triggered by Ro exposure could be attenuated by lithium carbonate (LC), which has anti-inflammatory properties. The initial protocol exposed earthworms to Ro (30 nM) and four different LC concentrations. LC at a concentration of 12.85 mg/L decreased SA and nitric oxide (NO) levels and was chosen to perform complementary assays: (1) neuromuscular damage evaluated by optical and scanning electron microscopy (SEM), (2) innate immune inefficiency by analysis of Eisenia spp. extracellular neutrophil traps (eNETs), and (3) behavioral changes. Gene expression was also evaluated involving mitochondrial (COII, ND1), inflammatory (EaTLR, AMP), and neuronal transmission (nAchR α5). LC attenuated the high melanized deposits in the circular musculature, fiber disarrangement, destruction of secretory glands, immune inefficiency, and impulsive behavior pattern triggered by Ro exposure. However, the effects of LC and Ro on gene expression were more heterogeneous. In summary, SA imbalance, potentially associated with mitochondrial dysfunction, appears to be an evolutionary component triggering oxidative, inflammatory, and behavioral changes observed in psychiatric disorders that are inhibited by LC exposure.

miR-15b-5p transcription mediated by CREB1 protects against inflammation and apoptosis in Parkinson disease models by inhibiting AXIN2 and activating Wnt/β-catenin

Parkinson disease (PD) is a major neurodegenerative disease that greatly undermines people's health and for which effective therapeutic strategies are currently limited. This study dissected the effects of expression changes of AXIN2, a modulator of the Wnt/beta-catenin signaling pathway, the transcription factor CREB1, and of the microRNA miR-15b-5p on apoptosis and the inflammatory response in a PD mouse model in vivo and in a cellular PD model in vitro. The analyses demonstrated low CREB1 and miR-15b-5p expression and high AXIN2 expression in both models. miR-15b-5p overexpression or AXIN2 knockdown alleviated the inflammatory response indicated by decreased levels of TNF-α, IL-6, and IL-1β and apoptosis indicated by decreased levels of cleaved caspase-3 and Bax and elevated Bcl-2. Protection by miR-15b-5p upregulation was counteracted by the simultaneous overexpression of AXIN2. miR-15b-5p targeted AXIN2. CREB1 promoted miR-15b-5p expression, which activated the Wnt/β-catenin pathway by inhibiting AXIN2. Collectively, the data indicate that transcriptional expression of miR-15b-5p can be promoted by CREB1 to inhibit AXIN2 and activate Wnt/β-catenin, thereby reducing the inflammatory response and apoptosis in these PD models. These data suggest the CREB1/miR-15b-5p/AXIN2 axis is a potential therapeutic target in PD patients.

Folic acid supplementation improved cognitive deficits associated with lithium administration during pregnancy in rat offspring

INTRODUCTION

The present study aimed to analyse both neurobehavioural and biochemical results of neonates born of mothers exposed to different doses of lithium along with the groups that received lithium at the highest dose with folic acid as a preventive treatment.

MATERIALS AND METHODS

Male and female rats were mated in separate cages, and pregnant rats were divided into eight first group as (1) vehicle; (2) propylthiouracil (PTU)-induced hypothyroidism; (3-4) received two different doses of lithium carbonate (15 and 30 mg/kg); (5-7) the highest doses of lithium (30 mg/kg) plus three different doses of folic acid (5, 10 and 15 mg/kg); and (8) received just folic acid (15 mg/kg). All treatments were dissolved in drinking water and continued until delivery, followed by returning to a regular diet without treatment.

RESULTS

Lithium (30 mg/kg) disrupts both behavioural and biochemical markers, including TSH, T3 and T4 as measuring indicators to assess thyroid function, IL-10 and TNF-α as anti-inflammatory and inflammatory agents, respectively, malondialdehyde as an oxidative stress marker, alongside SOD, and catalase activity as antioxidant indicators. Besides, folic acid, almost at the highest dose (15 mg/kg), attenuated memory impairement and anxiety-like behaviour caused by lithium. Moreover, the groups treated with folic acid alone in comparison with vehicles demonstrated higher levels of antioxidant and anti-inflammatory indicators.

CONCLUSION

According to the results, prenatal exposure to a high dose of lithium (30 mg/kg) leads to foetal neurodevelopmental disorder and growth restriction through various mechanisms more likely attributed to hypothyroidism, which means it should be either prohibited or prescribed cautiously during pregnancy.

Punicalagin's Protective Effects on Parkinson's Progression in Socially Isolated and Socialized Rats: Insights into Multifaceted Pathway

Parkinson's disease (PD) is a gradual deterioration of dopaminergic neurons, leading to motor impairments. Social isolation (SI), a recognized stressor, has recently gained attention as a potential influencing factor in the progress of neurodegenerative illnesses. We aimed to investigate the intricate relationship between SI and PD progression, both independently and in the presence of manganese chloride (MnCl2), while evaluating the punicalagin (PUN) therapeutic effects, a natural compound established for its cytoprotective, anti-inflammatory, and anti-apoptotic activities. In this five-week experiment, seven groups of male albino rats were organized: G1 (normal control), G2 (SI), G3 (MnCl2), G4 (SI + MnCl2), G5 (SI + PUN), G6 (MnCl2 + PUN), and G7 (SI + PUN + MnCl2). The results revealed significant changes in behavior, biochemistry, and histopathology in rats exposed to SI and/or MnCl2, with the most pronounced effects detected in the SI rats concurrently exposed to MnCl2. These effects were associated with augmented oxidative stress biomarkers and reduced antioxidant activity of the Nrf2/HO-1 pathway. Additionally, inflammatory pathways (HMGB1/RAGE/TLR4/NF-ᴋB/NLRP3/Caspase-1 and JAK-2/STAT-3) were upregulated, while dysregulation of signaling pathways (PI3K/AKT/GSK-3β/CREB), sustained endoplasmic reticulum stress by activation PERK/CHOP/Bcl-2, and impaired autophagy (AMPK/SIRT-1/Beclin-1 axis) were observed. Apoptosis induction and a decrease in monoamine levels were also noted. Remarkably, treatment with PUN effectively alleviated behaviour, histopathological changes, and biochemical alterations induced by SI and/or MnCl2. These findings emphasize the role of SI in PD progress and propose PUN as a potential therapeutic intervention to mitigate PD. PUN's mechanisms of action involve modulation of pathways such as HMGB1/RAGE/TLR4/NF-ᴋB/NLRP3/Caspase-1, JAK-2/STAT-3, PI3K/AKT/GSK-3β/CREB, AMPK/SIRT-1, Nrf2/HO-1, and PERK/CHOP/Bcl-2.

Unwinding the role of Wnt signaling cascade and molecular triggers of motor neuron degeneration in amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative condition, triggered by various factors causing the degeneration of upper and lower motor neurons, resulting in progressive muscle wasting, paralysis, and death. Multiple in vivo and in vitro models have been established to unravel the molecular events leading to the deterioration of motor neurons in ALS. The canonical and non-canonical Wnt signaling pathway has been implicated to play a crucial role in the progression of neurodegenerative disorders. This review discusses the role of Wnt signaling in the reported causes of ALS such as oxidative stress, mitochondrial dysfunction, autophagy, and apoptosis. Mutations in ALS-associated genes such as SOD1, C9orf72, TDP43, FUS, and OPTN cause an imbalance in neuronal integrity and homeostasis leading to motor neuron demise. Wnt signaling is also observed to play a crucial role in the muscle sparing of oculomotor neurons. The non-canonical Wnt/Ca2+ pathway which regulates intrinsic electrophysiological properties and mobilizes calcium ions to maintain neuronal integrity has been found to be altered in the stem cell-derived ALS model. Thus, the interplay of dysregulated canonical and non-canonical Wnt pathways in multiple motor neuron disease models has shown that Wnt contributes to disease progression indicating it to be utilized as a potential target for ALS.

Lithium Therapy in Old Age: Recommendations from a Delphi Survey

INTRODUCTION

While lithium (Li) has been well established for the treatment of bipolar disorder, geriatric patients require special attention when it comes to issues of drug safety. Declining renal function, amongst other medical conditions, and polypharmacy may pose increased risks. Only a few previous studies have addressed the management of Li in geriatric patients.

METHODS

Twenty-four German medical experts on geriatric medicine and Li treatment participated in a Delphi survey, consisting of two rounds of questionnaires and a final formulation of treatment recommendations. Three major issues of Li therapy were outlined: initiation of treatment, monitoring of ongoing therapy, and withdrawal due to medical reasons. Final recommendations were consented to at a threshold of at least 80% expert agreement.

RESULTS

Final consensus was achieved on 21 clinical recommendations. The approved recommendations covered aspects of necessary laboratory checks, concomitant medication, and target Li serum concentration in geriatric patients. Concerning the termination of Li therapy, an agreement was reached on the appropriate time span for tapering and on potential alternatives to Li. No consensus was achieved on whether concomitant dementia or frailty should be considered contraindications for Li treatment and the appropriate threshold of the estimated glomerular function rate for withdrawing Li.

CONCLUSION

According to the view of German experts, Li may be used in geriatric patients, but it should be monitored carefully. However, the lack of consent in several specific treatment situations underlines the need for research on specific issues of Li therapy.

Safety and efficacy of lithium in patients with amyotrophic lateral sclerosis: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

This study provides a systematic review and meta-analysis of randomized controlled trials (RCTs) investigating the safety and efficacy of lithium in amyotrophic lateral sclerosis (ALS) patients.

METHODS

PubMed, Web of Science, Cochrane CENTRAL, Scopus, and Your Journals@Ovid were searched up to 9 December 2022. RCTs investigating lithium, either alone or with any supplement, in ALS patients were included. Meta-analysis was performed using RevMan and results are presented in forest plot.

RESULTS

Four RCTs with 469 patients met the inclusion criteria and were included in our study. Lithium doses varied among the included studies and one study used a combined therapy of lithium with valproate. Meta-analysis showed no difference between lithium and placebo regarding severe adverse events (odds ratio = 1.13, 95% confidence interval: 0.73 to 1.75, P = 0.58). No significant differences were observed with regard to survival rate between the two groups (hazard ratio = 0.95, 95% confidence interval: 0.65 to 1.37, P = 0.77). There were also no significant differences between the two groups with regard to average changes of revised amyotrophic lateral sclerosis functional rating scale (P = 0.35) and forced vital capacity percentage predicted (P = 0.73). Subgroup analysis showed no significant differences regarding all investigated outcomes either for lithium alone or lithium with valproate.

CONCLUSION

Current evidence suggests a safety profile with no benefit of lithium for ALS. However, given the limited number of RCTs and the safety findings, we recommend further well-designed RCTs to investigate lithium and valproate in ALS patients.

Structural characterisation and degradation of Mg-Li thin films for biodegradable implants

Freestanding thin films of Mg-Li (magnesium-lithium) alloys with a Li mass fraction between 1.6% (m/m) and 9.5% (m/m) were prepared and studied with respect to their structure and degradation properties. With increasing Li content, the microstructure deviates from hexagonal Mg-Li with strict columnar growth and preferred orientation, and additional cubic Mg-Li and Li2CO3 occur. The corrosion rate was measured in Hanks' balanced salt solution by potentiodynamic polarisation and weight loss measurements to investigate biodegradation. Influences of the orientation, phase and protective layer formation lead to an increase in corrosion from 1.6 to 5.5% (m/m) from 0.13 ± 0.03 to 0.67 ± 0.29 mm/year when measured by potentiodynamic polarisation but a similar corrosion rate for 9.5% (m/m) and 3% (m/m) of Li of 0.27 ± 0.07 mm/year and 0.26 ± 0.05 mm/year.

An Overview of the Neurotrophic and Neuroprotective Properties of the Psychoactive Drug Lithium as an Autophagy Modulator in Neurodegenerative Conditions

For both short-term and long-term treatment of bipolar disorder, lithium is a prototypical mood stabilizer. Lithium's neuroprotective properties were revealed by cumulative translational research, which opened the door to reforming the chemical as a treatment for neurodegenerative illnesses. The control of homeostatic systems such as oxidative stress, autophagy, apoptosis, mitochondrial function, and inflammation underlies lithium's neuroprotective characteristics. The fact that lithium inhibits the enzymes inositol monophosphatase (IMPase) and glycogen synthase kinase (GSK)-3 may be the cause of the various intracellular reactions. In this article, we review lithium's neurobiological properties, as demonstrated by its neurotrophic and neuroprotective capabilities, as well as translational studies in cells in culture and in animal models of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Prion disease, amyotrophic lateral sclerosis (ALS), ischemic stroke, and neuronal ceroid lipofuscinosis (NCL), discussing the justification for the drug's use in the treatment of these neurodegenerative disorders.

Cognitive Impairment in Multiple Sclerosis

Almost three million individuals suffer from multiple sclerosis (MS) throughout the world, a demyelinating disease in the nervous system with increased prevalence over the last five decades, and is now being recognized as one significant etiology of cognitive loss and dementia. Presently, disease modifying therapies can limit the rate of relapse and potentially reduce brain volume loss in patients with MS, but unfortunately cannot prevent disease progression or the onset of cognitive disability. Innovative strategies are therefore required to address areas of inflammation, immune cell activation, and cell survival that involve novel pathways of programmed cell death, mammalian forkhead transcription factors (FoxOs), the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), and associated pathways with the apolipoprotein E (APOE-ε4) gene and severe acute respiratory syndrome coronavirus (SARS-CoV-2). These pathways are intertwined at multiple levels and can involve metabolic oversight with cellular metabolism dependent upon nicotinamide adenine dinucleotide (NAD+). Insight into the mechanisms of these pathways can provide new avenues of discovery for the therapeutic treatment of dementia and loss in cognition that occurs during MS.

WNT-β Catenin Signaling as a Potential Therapeutic Target for Neurodegenerative Diseases: Current Status and Future Perspective

Wnt/β-catenin (WβC) signaling pathway is an important signaling pathway for the maintenance of cellular homeostasis from the embryonic developmental stages to adulthood. The canonical pathway of WβC signaling is essential for neurogenesis, cell proliferation, and neurogenesis, whereas the noncanonical pathway (WNT/Ca²⁺ and WNT/PCP) is responsible for cell polarity, calcium maintenance, and cell migration. Abnormal regulation of WβC signaling is involved in the pathogenesis of several neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and spinal muscular atrophy (SMA). Hence, the alteration of WβC signaling is considered a potential therapeutic target for the treatment of neurodegenerative disease. In the present review, we have used the bibliographical information from PubMed, Google Scholar, and Scopus to address the current prospects of WβC signaling role in the abovementioned neurodegenerative diseases.

GSK-3β: An exuberating neuroinflammatory mediator in Parkinson's disease

Neuroinflammation is a critical degradative condition affecting neurons in the brain. Progressive neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease (PD) have been strongly linked to neuroinflammation. The trigger point for inflammatory conditions in the cells and body is the physiological immune system. The immune response mediated by glial cells and astrocytes can rectify the physiological alterations occurring in the cell for the time being but prolonged activation leads to pathological progression. The proteins mediating such an inflammatory response, as per the available literature, are undoubtedly GSK-3β, NLRP3, TNF, PPARγ, and NF-κB, along with a few other mediatory proteins. NLRP3 inflammasome is undeniably a principal instigator of the neuroinflammatory response, but the regulatory pathways controlling its activation are still unclear, besides less clarity for the interplay between different inflammatory proteins. Recent reports have suggested the involvement of GSK-3β in regulating NLRP3 activation, but the exact mechanistic pathway remains vague. In the current review, we attempt to provide an elaborate description of crosstalk between inflammatory markers and GSK-3β mediated neuroinflammation progression, linking it to regulatory transcription factors and posttranslational modification of proteins. The recent clinical therapeutic advances targeting these proteins are also discussed in parallel to provide a comprehensive view of the progress made in PD management and lacunas still existing in the field.

LincRNA-p21 Promotes Cellular Senescence by Down-regulating the Wnt/β-catenin Pathway in MPP+-treated SH-SY5Y Cells

AIM AND OBJECTIVE

Long intergenic non-coding RNA-p21 (lincRNA-p21) plays a critical role in various senescence-associated physiological and pathological conditions. We aimed to explore the senescence-associated effects of lincRNA-p21 in 1-methyl-4-phenylpyridinium (MPP+) treated neuroblastoma SH-SY5Y cell line as a therapeutic target.

MATERIALS AND METHODS

The RNA expression levels of lincRNA-p21, p53, p16, and telomere length were examined with reverse transcription-quantitative polymerase chain reaction (RTqPCR). The Telo TAGGG™ Telomerase PCR ELISA PLUS Kit was used to determine telomerase activity. Cellular viability was evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) assay. Western blot was performed to analyze β-catenin protein expression. Besides, oxidative stress was evaluated by Jaggregate- forming delocalized lipophilic cation, 5,5',6,6'-tetrachloro-1,1',3,3'- tetraethylbenzimidazolocarbocyanine++ + iodide (JC‑1) stain, fluorescence spectrophotometry, colorimetric assay, and malondialdehyde (MDA) formation.

RESULTS

This research demonstrated that MPP+ caused a distinct increase in the expression of LincRNA- p21 in SH-SY5Y cells. MPP+ induced cellular senescence with decreasing cellular proliferation and viability, increasing expression levels of senescence-associated makers such as genes p53 and p16, accompanied by significantly decreasing telomere length and telomerase activity. At the same time, these effects were abolished by silencing lincRNA-p21 with small interfering RNA (siRNA). On the contrary, β-catenin silencing contributes to reversing anti-senescent effects caused by lincRNA-p21 silencing. Moreover, modifying lincRNA-p21 exerted an anti-senescent influence depending on decreasing oxidant stress.

CONCLUSION

Our study showed that in the treatment of MPP+, lincRNA-p21 might serve a role in the SH-SY5Y cell senescence by modulating the Wnt/β-catenin pathway, as well as increasing oxidant stress. Thus, trying to target lincRNA-p21 may have important therapeutic and practical implications for PD.

2021 Editor's Choice Articles in the Section "Cells of the Nervous System"

Referenced below are the top 10 cited papers in 2021 from the Section "Cells of the Nervous System", published in Cells (ISSN: 2073-4409) [...].

The protective effect of thymoquinone or/and thymol against monosodium glutamate-induced attention-deficit/hyperactivity disorder (ADHD)-like behavior in rats: Modulation of Nrf2/HO-1, TLR4/NF-κB/NLRP3/caspase-1 and Wnt/β-Catenin signaling pathways in rat model

Both thymoquinone (TQ) and thymol (T) have been proved to possess a positive impact on human health. In this research, we aimed to investigate the effect of these compounds separately and together on the Attention-deficit/hyperactivity disorder (ADHD)-like behavior induced by monosodium glutamate (MSG) in rats. Forty male, Spargue Dawley rat pups (postnatal day 21), were randomly allocated into five groups: Normal saline (NS), MSG, MSG+TQ, MSG+T, and MSG+TQ+T. MSG (0.4 mg/kg/day), TQ (10 mg/kg/day) and T (30 mg/kg/day) were orally administered for 8 weeks. The behavioral tests proved that rats treated with TQ and/or T showed improved locomotor, attention and cognitive functions compared to the MSG group with more pronounced effect displayed with their combination. All treated groups showed improvement in MSG-induced aberrations in brain levels of GSH, IL-1β, TNF-α, GFAP, glutamate, calcium, dopamine, norepinephrine, Wnt3a, β-Catenin and BDNF. TQ and/or T treatment also enhanced the mRNA expression of Nrf2, HO-1 and Bcl2 while reducing the protein expression of TLR4, NFκB, NLRP3, caspase 1, Bax, AIF and GSK3β as compared to the MSG group. However, the combined therapy showed more significant effects in all measured parameters. All of these findings were further confirmed by the histopathological examinations. Current results concluded that the combined therapy of TQ and T had higher protective effects than their individual supplementations against MSG-induced ADHD-like behavior in rats.

Arterial Stiffness and the Canonical WNT/β-catenin Pathway

PURPOSE OF REVIEW

Arterial stiffness (AS) was mainly associated with cardiovascular morbidity and mortality in a hypertensive patient. Some risk factors contribute to the development of AS, such as aging, high blood pressure, vascular calcification, inflammation, and diabetes mellitus. The WNT/β-catenin pathway is implicated in numerous signaling and regulating pathways, including embryogenesis, cell proliferation, migration and polarity, apoptosis, and organogenesis. The activation of the WNT/β-catenin pathway is associated with the development of these risk factors.

RECENT FINDINGS

Aortic pulse wave velocity (PWV) is measured to determine AS, and in peripheral artery disease patients, PWV is higher than controls. An augmentation in PWV by 1 m/s has been shown to increase the risk of cardiovascular events by 14%. AS measured by PWV is characterized by the deregulation of the WNT/β-catenin pathway by the inactivation of its two inhibitors, i.e., DKK1 and sclerostin. Thus, this review focuses on the role of the WNT/β-catenin pathway which contributes to the development of arterial stiffness.

The Actions of Lithium on Glaucoma and Other Senile Neurodegenerative Diseases Through GSK-3 Inhibition: A Narrative Review

Glaucoma can be described as a set of progressive optic neuropathies. They cause a gradual, irreversible loss of the field of view, which concludes in complete blindness. Evidence suggests that patients who have glaucoma face a greater risk of suffering from senile dementia. Dementia is a group of conditions that occur in old age individuals. Neurodegeneration is a characteristic pathological feature of dementia, the progression of which causes a decline in cognition, which may be accompanied by memory loss. Severe dementia in old individuals usually presents as Alzheimer’s disease, which significantly contributes to a load of dementia in India. Parkinsonism is another common neurodegenerative disease that is known to occur in the elderly.

The WNT (Wingless-related integration site)/β-catenin pathway is a multistep process that is responsible for the regulation of various cellular functions. Lithium can up-regulate this pathway by disrupting Glycogen synthase kinase-3β (GSK-3β). This action of Lithium can effectively counteract neuroinflammation and neurodegeneration. The current use of Lithium remains majorly confined to its use for episodes of mania in bipolar disorder (BD). However, recent literature gives insight into how Lithium can improve the visual field in glaucomatous eyes. Symptomatic improvement after lithium administration is seen as it has neuroprotective actions on the retinal ganglion cells (RGCs). Prolonged lithium use improves axonal regeneration and neuronal survival. Lithium also improves the worsening of symptoms in other dementia-related neurodegenerative diseases like Alzheimer’s and Parkinsonism. The physiological actions of Lithium can be utilized in providing effective, holistic therapy options in pathologically related senile degenerative disorders. Significantly better results can be obtained if Lithium therapy is given in conjunction with the drugs used to manage these disorders.

Nitrosative stress in Parkinson's disease

Parkinson’s Disease (PD) is a neurodegenerative disorder characterized, in part, by the loss of dopaminergic neurons within the nigral-striatal pathway. Multiple lines of evidence support a role for reactive nitrogen species (RNS) in degeneration of this pathway, specifically nitric oxide (NO). This review will focus on how RNS leads to loss of dopaminergic neurons in PD and whether RNS accumulation represents a central signal in the degenerative cascade. Herein, we provide an overview of how RNS accumulates in PD by considering the various cellular sources of RNS including nNOS, iNOS, nitrate, and nitrite reduction and describe evidence that these sources are upregulating RNS in PD. We document that over 1/3 of the proteins that deposit in Lewy Bodies, are post-translationally modified (S-nitrosylated) by RNS and provide a broad description of how this elicits deleterious effects in neurons. In doing so, we identify specific proteins that are modified by RNS in neurons which are implicated in PD pathogenesis, with an emphasis on exacerbation of synucleinopathy. How nitration of alpha-synuclein (aSyn) leads to aSyn misfolding and toxicity in PD models is outlined. Furthermore, we delineate how RNS modulates known PD-related phenotypes including axo-dendritic-, mitochondrial-, and dopamine-dysfunctions. Finally, we discuss successful outcomes of therapeutics that target S-nitrosylation of proteins in Parkinson’s Disease related clinical trials. In conclusion, we argue that targeting RNS may be of therapeutic benefit for people in early clinical stages of PD.

Crosstalk between regulatory non-coding RNAs and oxidative stress in Parkinson’s disease

Parkinson’s disease is the second most common neurodegenerative disease after Alzheimer’s disease, which imposes an ever-increasing burden on society. Many studies have indicated that oxidative stress may play an important role in Parkinson’s disease through multiple processes related to dysfunction or loss of neurons. Besides, several subtypes of non-coding RNAs are found to be involved in this neurodegenerative disorder. However, the interplay between oxidative stress and regulatory non-coding RNAs in Parkinson’s disease remains to be clarified. In this article, we comprehensively survey and overview the role of regulatory ncRNAs in combination with oxidative stress in Parkinson’s disease. The interaction between them is also summarized. We aim to provide readers with a relatively novel insight into the pathogenesis of Parkinson’s disease, which would contribute to the development of pre-clinical diagnosis and treatment.

Role of heavy metals (copper (Cu), arsenic (As), cadmium (Cd), iron (Fe) and lithium (Li)) induced neurotoxicity

Parkinson's disease (PD) is a neurodegenerative condition characterized by the dopamine (DA) neuronal loss in the substantia nigra. PD impairs motor controls symptoms such as tremor, rigidity, bradykinesia and postural imbalance gradually along with non-motor problems such as olfactory dysfunction, constipation, sleeping disorder. Though surplus of factors and mechanisms have been recognized, the precise PD etiopathogenesis is not yet implied. Reports suggest that various environmental factors play a crucial role in the causality of the PD cases. Epidemiological studies have reported that heavy metals has a role in causing defects in substantia nigra region of brain in PD. Though the reason is unknown, exposure to heavy metals is reported to be an underlying factor in PD development. Metals are classified as either essential or non-essential, and they have a role in physiological processes such protein modification, electron transport, oxygen transport, redox reactions, and cell adhesion. Excessive metal levels cause oxidative stress, protein misfolding, mitochondrial malfunction, autophagy dysregulation, and apoptosis, among other things. In this review, we check out the link between heavy metals like copper (Cu), arsenic (As), cadmium (Cd), iron (Fe), and lithium (Li) in neurodegeneration, and how it impacts the pathological conditions of PD. In conclusion, increase or decrease in heavy metals involve in regulation of neuronal functions that have an impact on neurodegeneration process. Through this review, we suggest that more research is needed in this stream to bring more novel approaches for either disease modelling or therapeutics.

Potential mechanisms underlying lithium treatment for Alzheimer's disease and COVID-19

Disruption of intracellular Ca2+ homeostasis plays an important role as an upstream pathology in Alzheimer's disease (AD), and correction of Ca2+ dysregulation has been increasingly proposed as a target of future effective disease-modified drugs for treating AD. Calcium dysregulation is also an upstream pathology for the COVID-19 virus SARS-CoV-2 infection and replication, leading to host cell damage. Clinically available drugs that can inhibit the disturbed intracellular Ca2+ homeostasis have been repurposed to treat COVID-19 patients. This narrative review aims at exploring the underlying mechanism by which lithium, a first line drug for the treatment of bipolar disorder, inhibits Ca2+ dysregulation and associated downstream pathology in both AD and COVID-19. It is suggested that lithium can be repurposed to treat AD patients, especially those afflicted with COVID-19.

Glycogen Synthase Kinase-3 Inhibitors: Preclinical and Clinical Focus on CNS-A Decade Onward

The protein kinase, GSK-3, participates in diverse biological processes and is now recognized a promising drug discovery target in treating multiple pathological conditions. Over the last decade, a range of newly developed GSK-3 inhibitors of diverse chemotypes and inhibition modes has been developed. Even more conspicuous is the dramatic increase in the indications that were tested from mood and behavior disorders, autism and cognitive disabilities, to neurodegeneration, brain injury and pain. Indeed, clinical and pre-clinical studies were largely expanded uncovering new mechanisms and novel insights into the contribution of GSK-3 to neurodegeneration and central nerve system (CNS)-related disorders. In this review we summarize new developments in the field and describe the use of GSK-3 inhibitors in the variety of CNS disorders. This remarkable volume of information being generated undoubtedly reflects the great interest, as well as the intense hope, in developing potent and safe GSK-3 inhibitors in clinical practice.

Chronic lithium administration in a mouse model for Krabbe disease

Krabbe disease (KD; or globoid cell leukodystrophy) is an autosomal recessive lysosomal storage disorder caused by deficiency of the galactosylceramidase (GALC) enzyme. No cure is currently available for KD. Clinical applied treatments are supportive only. Recently, we demonstrated that two differently acting autophagy inducers (lithium and rapamycin) can improve some KD hallmarks in-vitro, laying the foundation for their in-vivo pre-clinical testing. Here, we test lithium carbonate in-vivo, in the spontaneous mouse model for KD, the Twitcher (TWI) mouse. The drug is administered ad libitum via drinking water (600 mg/L) starting from post natal day 20. We longitudinally monitor the mouse motor performance through the grip strength, the hanging wire and the rotarod tests, and a set of biochemical parameters related to the KD pathogenesis [i.e., GALC enzymatic activity, psychosine (PSY) accumulation and astrogliosis]. Additionally, we investigate the expression of some crucial markers related to the two pathways that could be altered by lithium: the autophagy and the β-catenin-dependent pathways. Results demonstrate that lithium has not a significant rescue effect on the TWI phenotype, although it can slightly and transiently improves muscle strength. We also show that lithium, with this administration protocol, is unable to stimulate autophagy in the TWI mice central nervous system, whereas results suggest that it can restore the β-catenin activation status in the TWI sciatic nerve. Overall, these data provide intriguing inputs for further evaluations of lithium treatment in TWI mice.

Cold Plasma Irradiation Regulates Inflammation and Oxidative Stress in Human Bronchial Epithelial Cells and Human Non-Small Cell Lung Carcinoma

Atmospheric pressure cold plasma has shown multiple biological effects of anti-bacteria and anti-cancer. In this study, the effect of atmospheric pressure cold plasma on respiratory inflammation and oxidant stress is explored. Tunicamycin was used to stimulate human bronchial epithelial cells (HBECs) and A549 cells for inflammatory response and oxidative stress, followed by atmospheric pressure cold plasma treatment. For HBECs and A549 cells, atmospheric pressure cold plasma was able to alleviate tunicamycin-induced cell proliferation inhibition, inflammation and oxidant stress, and enhance nuclear factor-erythroid-2-related factor 2 (NRF2) pathway activation. Moreover, NRF2/ARE (anti-oxidant response elements) pathway was involved in the regulation of atmospheric pressure cold plasma on tunicamycin-induced oxidative stress. These results suggest the positive effect of atmospheric pressure cold plasma on inflammation and oxidant stress of respiratory system, indicating the therapeutic potential of atmospheric pressure cold plasma for respiratory diseases.

Cholinergic Receptor Modulation as a Target for Preventing Dementia in Parkinson's Disease

Parkinson’s disease (PD) is a neurodegenerative condition characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) in the midbrain resulting in progressive impairment in cognitive and motor abilities. The physiological and molecular mechanisms triggering dopaminergic neuronal loss are not entirely defined. PD occurrence is associated with various genetic and environmental factors causing inflammation and mitochondrial dysfunction in the brain, leading to oxidative stress, proteinopathy, and reduced viability of dopaminergic neurons. Oxidative stress affects the conformation and function of ions, proteins, and lipids, provoking mitochondrial DNA (mtDNA) mutation and dysfunction. The disruption of protein homeostasis induces the aggregation of alpha-synuclein (α-SYN) and parkin and a deficit in proteasome degradation. Also, oxidative stress affects dopamine release by activating ATP-sensitive potassium channels. The cholinergic system is essential in modulating the striatal cells regulating cognitive and motor functions. Several muscarinic acetylcholine receptors (mAChR) and nicotinic acetylcholine receptors (nAChRs) are expressed in the striatum. The nAChRs signaling reduces neuroinflammation and facilitates neuronal survival, neurotransmitter release, and synaptic plasticity. Since there is a deficit in the nAChRs in PD, inhibiting nAChRs loss in the striatum may help prevent dopaminergic neurons loss in the striatum and its pathological consequences. The nAChRs can also stimulate other brain cells supporting cognitive and motor functions. This review discusses the cholinergic system as a therapeutic target of cotinine to prevent cognitive symptoms and transition to dementia in PD.

Bioactivity and Antibacterial Behaviors of Nanostructured Lithium-Doped Hydroxyapatite for Bone Scaffold Application

The material for bone scaffold replacement should be biocompatible and antibacterial to prevent scaffold-associated infection. We biofunctionalized the hydroxyapatite (HA) properties by doping it with lithium (Li). The HA and 4 Li-doped HA (0.5, 1.0, 2.0, 4.0 wt.%) samples were investigated to find the most suitable Li content for both aspects. The synthesized nanoparticles, by the mechanical alloying method, were cold-pressed uniaxially and then sintered for 2 h at 1250 °C. Characterization using field-emission scanning electron microscopy (FE-SEM) revealed particle sizes in the range of 60 to 120 nm. The XRD analysis proved the formation of HA and Li-doped HA nanoparticles with crystal sizes ranging from 59 to 89 nm. The bioactivity of samples was investigated in simulated body fluid (SBF), and the growth of apatite formed on surfaces was evaluated using SEM and EDS. Cellular behavior was estimated by MG63 osteoblast-like cells. The results of apatite growth and cell analysis showed that 1.0 wt.% Li doping was optimal to maximize the bioactivity of HA. Antibacterial characteristics against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were performed by colony-forming unit (CFU) tests. The results showed that Li in the structure of HA increases its antibacterial properties. HA biofunctionalized by Li doping can be considered a suitable option for the fabrication of bone scaffolds due to its antibacterial and unique bioactivity properties.

Opposed Interplay between IDH1 Mutations and the WNT/β-Catenin Pathway: Added Information for Glioma Classification

Gliomas are the main common primary intraparenchymal brain tumor in the central nervous system (CNS), with approximately 7% of the death caused by cancers. In the WHO 2016 classification, molecular dysregulations are part of the definition of particular brain tumor entities for the first time. Nevertheless, the underlying molecular mechanisms remain unclear. Several studies have shown that 75% to 80% of secondary glioblastoma (GBM) showed IDH1 mutations, whereas only 5% of primary GBM have IDH1 mutations. IDH1 mutations lead to better overall survival in gliomas patients. IDH1 mutations are associated with lower stimulation of the HIF-1α a, aerobic glycolysis and angiogenesis. The stimulation of HIF-1α and the process of angiogenesis appears to be activated only when hypoxia occurs in IDH1-mutated gliomas. In contrast, the observed upregulation of the canonical WNT/β-catenin pathway in gliomas is associated with proliferation, invasion, aggressive-ness and angiogenesis.. Molecular pathways of the malignancy process are involved in early stages of WNT/β-catenin pathway-activated-gliomas, and this even under normoxic conditions. IDH1 mutations lead to decreased activity of the WNT/β-catenin pathway and its enzymatic targets. The opposed interplay between IDH1 mutations and the canonical WNT/β-catenin pathway in gliomas could participate in better understanding of the observed evolution of different tumors and could reinforce the glioma classification.

Lithium and Atypical Antipsychotics: The Possible WNT/β Pathway Target in Glaucoma

Glaucoma is a progressive neurodegenerative disease that represents the major cause of irreversible blindness. Recent findings have shown which oxidative stress, inflammation, and glutamatergic pathway have main roles in the causes of glaucoma. Lithium is the major commonly used drug for the therapy of chronic mental illness. Lithium therapeutic mechanisms remain complex, including several pathways and gene expression, such as neurotransmitter and receptors, circadian modulation, ion transport, and signal transduction processes. Recent studies have shown that the benefits of lithium extend beyond just the therapy of mood. Neuroprotection against excitotoxicity or brain damages are other actions of lithium. Moreover, recent findings have investigated the role of lithium in glaucoma. The combination of lithium and atypical antipsychotics (AAPs) has been the main common choice for the treatment of bipolar disorder. Due to the possible side effects gradually introduced in therapy. Currently, no studies have focused on the possible actions of AAPs in glaucoma. Recent studies have shown a down regulation of the WNT/β-catenin pathway in glaucoma, associated with the overactivation of the GSK-3β signaling. The WNT/β-catenin pathway is mainly associated with oxidative stress, inflammation and glutamatergic pathway. Lithium is correlated with upregulation the WNT/β-catenin pathway and downregulation of the GSK-3β activity. Thus, this review focuses on the possible actions of lithium and AAPs, as possible therapeutic strategies, on glaucoma and some of the presumed mechanisms by which these drugs provide their possible benefit properties through the WNT/β-catenin pathway.

Interplay of Opposing Effects of the WNT/β-Catenin Pathway and PPARγ and Implications for SARS-CoV2 Treatment

The Coronavirus disease 2019 (COVID-19), caused by the novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), has quickly reached pandemic proportions. Cytokine profiles observed in COVID-19 patients have revealed increased levels of IL-1β, IL-2, IL-6, and TNF-α and increased NF-κB pathway activity. Recent evidence has shown that the upregulation of the WNT/β-catenin pathway is associated with inflammation, resulting in a cytokine storm in ARDS (acute respire distress syndrome) and especially in COVID-19 patients. Several studies have shown that the WNT/β-catenin pathway interacts with PPARγ in an opposing interplay in numerous diseases. Furthermore, recent studies have highlighted the interesting role of PPARγ agonists as modulators of inflammatory and immunomodulatory drugs through the targeting of the cytokine storm in COVID-19 patients. SARS-CoV2 infection presents a decrease in the angiotensin-converting enzyme 2 (ACE2) associated with the upregulation of the WNT/β-catenin pathway. SARS-Cov2 may invade human organs besides the lungs through the expression of ACE2. Evidence has highlighted the fact that PPARγ agonists can increase ACE2 expression, suggesting a possible role for PPARγ agonists in the treatment of COVID-19. This review therefore focuses on the opposing interplay between the canonical WNT/β-catenin pathway and PPARγ in SARS-CoV2 infection and the potential beneficial role of PPARγ agonists in this context.

Cannabidiol and the Canonical WNT/β-Catenin Pathway in Glaucoma

Glaucoma is a progressive neurodegenerative disease which constitutes the main frequent cause of irreversible blindness. Recent findings have shown that oxidative stress, inflammation and glutamatergic pathway play key roles in the causes of glaucoma. Recent studies have shown a down regulation of the WNT/β-catenin pathway in glaucoma, associated with overactivation of the GSK-3β signaling. WNT/β-catenin pathway is mainly associated with oxidative stress, inflammation and glutamatergic pathway. Cannabidiol (CBD) is a non-psychotomimetic phytocannabinoid derived from Cannabis sativa plant which possesses many therapeutic properties across a range of neuropsychiatric disorders. Since few years, CBD presents an increased interest as a possible drug in anxiolytic disorders. CBD administration is associated with increase of the WNT/β-catenin pathway and decrease of the GSK-3β activity. CBD has a lower affinity for CB1 but can act through other signaling in glaucoma, including the WNT/β-catenin pathway. CBD downregulates GSK3-β activity, an inhibitor of WNT/β-catenin pathway. Moreover, CBD was reported to suppress pro-inflammatory signaling and neuroinflammation, oxidative stress and glutamatergic pathway. Thus, this review focuses on the potential effects of cannabidiol, as a potential therapeutic strategy, on glaucoma and some of the presumed mechanisms by which this phytocannabinoid provides its possible benefit properties through the WNT/β-catenin pathway.

Necrotizing Enterocolitis: LPS/TLR4-Induced Crosstalk Between Canonical TGF-β/Wnt/β-Catenin Pathways and PPARγ

Necrotizing enterocolitis (NEC) represents one of the major causes of morbidity and mortality in premature infants. Several recent studies, however, have contributed to a better understanding of the pathophysiology of this dreadful disease. Numerous intracellular pathways play a key role in NEC, namely: bacterial lipopolysaccharide (LPS), LPS toll-like receptor 4 (TLR4), canonical Wnt/β-catenin signaling and PPARγ. In a large number of pathologies, canonical Wnt/β-catenin signaling and PPARγ operate in opposition to one another, so that when one of the two pathways is overexpressed the other is downregulated and vice-versa. In NEC, activation of TLR4 by LPS leads to downregulation of the canonical Wnt/β-catenin signaling and upregulation of PPARγ. This review aims to shed light on the complex intracellular mechanisms involved in this pathophysiological profile by examining additional pathways such as the GSK-3β, NF-κB, TGF-β/Smads, and PI3K-Akt pathways.