Neuroprotective Effects of Exogenous Irisin in Kainic Acid-Induced Status Epilepticus

Neuropharmacological insights into Gardenia jasminoides Ellis: Harnessing therapeutic potential for central nervous system disorders

BACKGROUND

In China, Gardenia jasminoides Ellis (GJE) has a longstanding history of application. The Ministry of Health has listed it as one of the first pharmaceutical or food resources. In ethnic, traditional, and folk medicine, GJE has been used to treat fever and cold and relieve nervous anxiety. Recent studies have confirmed the significant efficacy of GJE for treating central nervous system (CNS) disorders, including Alzheimer's disease, Parkinson's disease, and major depressive disorder; however, GJE has not been systematically evaluated.

PURPOSE

This research systematically summarizes global studies on the use of GJE for treating CNS disorders and explores the potential applications and underlying mechanisms via intestinal flora analysis and network pharmacology, aiming to establish a scientific basis for innovative CNS disorder treatment with GJE.

METHODS

The PRISMA guidelines were used, and electronic databases such as the Web of Science, PubMed, and China National Knowledge Infrastructure were searched using the following search terms: "Gardenia jasminoides Ellis" with "central nervous system disease," "neuroprotection," "Alzheimer's disease," "Parkinson's disease," "ischemic stroke," "Epilepsy," and "major depressive disorder." The published literature up to September 2023 was searched to obtain relevant information on the application of GJE for treating CNS disorders.

RESULTS

There has been an increase in research on the material formulation and mechanisms of action of GJE for treating CNS disorders, with marked effects on CNS disorder treatment in different countries and regions. We summarized the research results related to the role of GJE in vitro and in vivo via multitargeted interventions in response to the complex mechanisms of action of CNS disorders.

CONCLUSION

We systematically reviewed the research progress on traditional treatment for GJE and preclinical mechanisms of CNS disorders and explored the potential of optimizing network pharmacology strategies and intestinal flora analysis to elucidate the mechanisms of action of GJE. The remarkable therapeutic efficacy of GJE, an important resource in traditional medicine, has been well documented in the literature, highlighting its significant medicinal potential.

Increased thrombospondin-1 levels contribute to epileptic susceptibility in neonatal hyperthermia without seizures via altered synaptogenesis

Childhood febrile seizures (FS) represent one of the most common types of seizures and may lead to severe neurological damage and an increased risk of epilepsy. However, most children with fevers do not show clinical manifestations of convulsions, and the consequences of hyperthermia without seizures remain elusive. This study focused on hyperthermia not reaching the individual's seizure threshold (sub-FS stimulus). Changes in thrombospondin-1 (TSP-1) levels, synapses, seizure susceptibility, and seizure severity in subsequent FS were investigated in rats exposed to sub-FS stimuli. Pharmacological and genetic interventions were used to explore the role of TSP-1 in sub-FS-induced effects. We found that after sub-FS stimuli, the levels of TSP-1 and synapses, especially excitatory synapses, were concomitantly increased, with increased epilepsy and FS susceptibility. Moreover, more severe neuronal damage was found in subsequent FS. These changes were temperature dependent. Reducing TSP-1 levels by genetic intervention or inhibiting the activation of transforming growth factor-β1 (TGF-β1) by Leu-Ser-Lys-Leu (LSKL) led to lower synapse/excitatory synapse levels, decreased epileptic susceptibility, and attenuated neuronal injury after FS stimuli. Our study confirmed that even without seizures, hyperthermia may promote synaptogenesis, increase epileptic and FS susceptibility, and lead to more severe neuronal damage by subsequent FS. Inhibition of the TSP-1/TGF-β1 pathway may be a new therapeutic target to prevent detrimental sub-FS sequelae.

Stabilization of mitochondrial function by chlorogenic acid protects against kainic acid-induced seizures and neuronal cell death in rats

The current study investigated the effect of chlorogenic acid, a polyphenolic compound found in numerous plant products, on a kainic acid-induced seizure rat model and its potential mechanism. Rats were administered chlorogenic acid (10 and 50 mg/kg) intraperitoneally for 30 min before kainic acid (15 mg/kg) intraperitoneal administration. Pretreatment with chlorogenic acid decreased the seizure score, increased the latency to onset of the first seizure, and decreased the mortality rate. Chlorogenic acid pretreatment also resulted in a significant reduction in glutamate elevation and neuronal death in the hippocampus of kainic acid-treated rats. In addition, electron microscopy revealed that kainic acid-induced changes in hippocampal mitochondrial structure were prevented by chlorogenic acid pretreatment. Additionally, the levels of mitochondrial function-related proteins, including sirtuin 3, Complex I, glutamate dehydrogenase 1 and ATP synthase, were increased, and the level of the mitochondrial damage marker cytochrome C was decreased in the hippocampus of chlorogenic acid/kainic acid rats. Furthermore, the expression of mitochondrial biogenesis-related proteins [AMP-activated protein kinase (AMPK), sirtuin1, and peroxisome proliferator-activated receptor γ-coactivator-1α (PGC-1α)] and mitophagy-related proteins [phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1), Parkin, and microtubule-associated protein 1 light chain 3 (LC3)] was decreased in the hippocampus of kainic acid-treated rats, which was reversed by chlorogenic acid pretreatment. These observations reveal the marked neuroprotective potential of chlorogenic acid against kainic acid-induced neurotoxicity and seizures through prevention of glutamate increase and preservation of AMPK/sirtuin 1/PGC-1α-mediated mitochondrial biogenesis and PINK1/Parkin-induced mitophagy to maintain adequate mitochondrial homeostasis and function.

Xenon inhalation attenuates neuronal injury and prevents epilepsy in febrile seizure Sprague-Dawley pups

Background

Febrile seizures (FS) usually occur in childhood and may cause irreversible neuronal damage, cognitive functional defects, and an increase in the risk of epilepsy later in life. Anti-epileptic drugs (AEDs), currently used to treat FS in children, can relieve seizures. However, their effects in preventing the risk of developing epilepsy in later life are unsatisfactory. Moreover, AEDs may damage child brain development. Here, we evaluated the efficiency of xenon in treating prolonged FS (PFS) and preventing epilepsy in Sprague-Dawley pups.

Methods

Prolonged FS was induced by hyperthermic treatment. After 90 min of PFS, the pups in the xenon treatment group were immediately treated with 70% xenon/21% oxygen/9% nitrogen for 60 min. The levels of glutamate, mitochondrial oxidative stress, mitophagy, and neuronal injury, seizures, learning, and memory functions were measured at specific time points.

Results

Neonatal period PFS led to spontaneous seizure, learning and memory dysfunction, accompanied by increased levels of glutamate, mitochondrial oxidative stress, mitophagy, and neuronal injury. Xenon treatment alleviated the changes caused by PFS and reduced the risk of PFS developing into epilepsy later.

Conclusion

Our results suggest that xenon inhalation could be a potential therapeutic strategy to attenuate neuronal injury and prevent epilepsy in patients with FS.

Neuroplasticity to autophagy cross-talk in a therapeutic effect of physical exercises and irisin in ADHD

Adaptive neuroplasticity is a pivotal mechanism for healthy brain development and maintenance, as well as its restoration in disease- and age-associated decline. Management of mental disorders such as attention deficit hyperactivity disorder (ADHD) needs interventions stimulating adaptive neuroplasticity, beyond conventional psychopharmacological treatments. Physical exercises are proposed for the management of ADHD, and also depression and aging because of evoked brain neuroplasticity. Recent progress in understanding the mechanisms of muscle-brain cross-talk pinpoints the role of the myokine irisin in the mediation of pro-cognitive and antidepressant activity of physical exercises. In this review, we discuss how irisin, which is released in the periphery as well as derived from brain cells, may interact with the mechanisms of cellular autophagy to provide protein recycling and regulation of brain-derived neurotrophic factor (BDNF) signaling via glia-mediated control of BDNF maturation, and, therefore, support neuroplasticity. We propose that the neuroplasticity associated with physical exercises is mediated in part by irisin-triggered autophagy. Since the recent findings give objectives to consider autophagy-stimulating intervention as a prerequisite for successful therapy of psychiatric disorders, irisin appears as a prototypic molecule that can activate autophagy with therapeutic goals.

Irisin: A bridge between exercise and neurological diseases

Exercise plays a beneficial regulating role on each organ of the body through different mechanisms and is a powerful weapon to prevent disease. Irisin is released from muscle and widely distributed in the human body, participating in the physiological processes of multiple human systems and playing a protective role in multiple human organs. The protective effect of irisin on the nervous system is particularly remarkable, which can improve cognitive function, reduce the risk of ischemic stroke and improve its prognosis. Irisin also plays a guiding role in the prevention and treatment of neurodegenerative diseases and ischemic cerebrovascular diseases. Exercise is the driving factor promoting irisin secretion, and different exercise modes, intensity, frequency, and time all affect the level of serum irisin. As a result of analyzing the effects of various exercise modes on irisin secretion, we proposed an exercise program with a higher level of irisin secretion.

Attenuated iron stress and oxidative stress may participate in anti-seizure and neuroprotective roles of xenon in pentylenetetrazole-induced epileptogenesis

The previous studies have demonstrated the excellent neuroprotective effects of xenon. In this study, we verified the anti-seizure and neuroprotective roles of xenon in epileptogenesis and evaluated the involvement of oxidative stress and iron accumulation in the protective roles of xenon. Epileptogenesis was induced by pentylenetetrazole (PTZ) treatment in Sprague-Dawley rats. During epileptogenesis, we found increased levels of iron and oxidative stress accompanied by elevated levels of divalent metal transporter protein 1 and iron regulatory protein 1, which are closely associated with iron accumulation. Meanwhile, the levels of autophagy and mitophagy increased, alongside significant neuronal damage and cognitive deficits. Xenon treatment reversed these effects: oxidative stress and iron stress were reduced, neuronal injury and seizure severity were attenuated, and learning and memory deficits were improved. Thus, our results confirmed the neuroprotective and anti-seizure effects of xenon treatment in PTZ-induced epileptogenesis. The reduction in oxidative and iron stress may be the main mechanisms underlying xenon treatment. Thus, this study provides a potential intervention strategy for epileptogenesis.

An aqueous extract of Syzygium cumini protects against kainate-induced status epilepticus and amnesia: evidence for antioxidant and anti-inflammatory intervention

Temporal lobe epilepsy is the most common drug-resistant epilepsy. To cure epilepsy, drugs must target the mechanisms at the origin of seizures. Thus, the present investigation aimed to evaluate the antiepileptic- and anti-amnesic-like effects of an aqueous extract of Syzygium cumini against kainate-induced status epilepticus in mice, and possible mechanisms of action. Mice were divided into 7 groups and treated as follows: normal group or kainate group received po distilled water (10 mL/kg), four test groups received Syzygium cumini (28.8, 72, 144, and 288 mg/kg, po), and the positive control group treated intraperitoneally (ip) with sodium valproate (300 mg/kg). An extra group of normal mice was treated with piracetam (200 mg/kg, po). Treatments were administered 60 min before the induction of status epilepticus with kainate (15 mg/kg, ip), and continued daily throughout behavioral testing. Twenty-four hours after the induction, T-maze and Morris water maze tasks were successively performed. The animals were then sacrificed and some markers of oxidative stress and neuroinflammation were estimated in the hippocampus. The extract significantly prevented status epilepticus and mortality. In the T-maze, the aqueous extract markedly increased the time spent and the number of entries in the discriminated arm. In the Morris water maze, the extract significantly increased the time spent in the target quadrant during the retention phase. Furthermore, the aqueous extract induced a significant reduction of oxidative stress and neuroinflammation. These results suggest that the aqueous extract of Syzygium cumini has antiepileptic- and anti-amnesic-like effects, likely mediated in part by antioxidant and anti-inflammatory activities.

Irisin, an Effective Treatment for Cardiovascular Diseases?

Irisin, as one of the myokines induced by exercise, has attracted much attention due to its important physiological functions such as white fat browning, the improvement in metabolism, and the alleviation of inflammation. Despite the positive role that irisin has been proven to play in the prevention and treatment of cardiovascular diseases, whether it can become a biomarker and potential target for predicting and treating cardiovascular diseases remains controversial, given the unreliability of its detection methods, the uncertainty of its receptors, and the species differences between animals and humans. This paper was intended to review the role of irisin in the diagnosis and treatment of cardiovascular diseases, the potential molecular mechanism, and the urgent problems to be solved in hopes of advancing our understanding of irisin as well as providing data for the development of new and promising intervention strategies by discussing the causes of contradictory results.

Irisin: A promising treatment for neurodegenerative diseases

The beneficial effects of exercise on human brain function have been demonstrated in previous studies. Myokines secreted by muscle have attracted increasing attention because of their bridging role between exercise and brain health. Regulated by PPARγ coactivator 1α, fibronectin type III domain-containing protein 5 releases irisin after proteolytic cleavage. Irisin, a type of myokine, is secreted during exercise, which induces white adipose tissue browning and relates to energy metabolism. Recently, irisin has been shown to exert a protective effect on the central nervous system. Irisin secretion triggers an increase in brain-derived neurotrophic factor levels in the hippocampus, contributing to the amelioration of cognition impairments. Irisin also plays an important role in the survival, differentiation, growth, and development of neurons. This review summarizes the role of irisin in neurodegenerative diseases and other neurological disorders. As a novel positive mediator of exercise in the brain, irisin may effectively prevent or decelerate the progress of neurodegenerative diseases in models and also improve cognitive functions. We place emphasis herein on the potential of irisin for prevention rather than treatment in neurodegenerative diseases. In ischemic diseases, irisin can alleviate the pathophysiological processes associated with stroke. Meanwhile, irisin has anxiolytic and antidepressant effects. The potential therapeutic effects of irisin in epilepsy and pain have been initially revealed. Due to the pleiotropic and beneficial properties of irisin, the possibility of irisin treating other neurological diseases could be gradually explored in the future.

Mechanism of CNS regulation by irisin, a multifunctional protein

Exercise not only builds up our body but also improves cognitive function. Skeletal muscle secretes myokine during exercise as a large reservoir of signaling molecules, which can be considered as a medium between exercise and brain health. Irisin is a circulating myokine derived from the Fibronectin type III domain-containing protein 5 (FNDC5). Irisin regulates energy metabolism because it can stimulate the "Browning" of white adipose tissue. It has been reported that irisin can cross the blood-brain barrier and increase the expression of a brain-derived neurotrophic factor (BDNF) in the hippocampus, which improves learning and memory. In addition, the neuroprotective effect of irisin has been verified in various disease models. Therefore, this review summarizes how irisin plays a neuroprotective role, including its signal pathway and mechanism. In addition, we will briefly discuss the therapeutic potential of irisin for neurological diseases.