Smo-Shh signaling activator purmorphamine ameliorates neurobehavioral, molecular, and morphological alterations in an intracerebroventricular propionic acid-induced experimental model of autism

Purmorphamine Alters Anxiety-Like Behavior and Expression of Hedgehog Cascade Components in Rat Brain after Alcohol Withdrawal

Disturbances in the Hedgehog (Hh) signaling play an important role in dysmorphogenesis of bone tissue and central nervous system during prenatal alcohol exposure, which underlies development of fetal alcohol syndrome. The involvement of Hh proteins in the mechanisms of alcohol intake in adults remains obscure. We investigated the role of the Hh cascade in voluntary ethanol drinking and development of anxiety-like behavior (ALB) during early abstinence and assessed changes in the expression of Hh pathway components in different brain regions of male Wistar rats in a model of voluntary alcohol drinking using the intermittent access to 20% ethanol in a two-bottle choice procedure. Purmorphamine (Hh cascade activator and Smoothened receptor agonist) was administered intraperitoneally at a dose of 5 mg/kg body weight prior to 16-20 sessions of alcohol access. Purmorphamine had no effect on the ethanol preference; however, rats exposed to ethanol and receiving purmorphamine demonstrated changes in the ALB during the early abstinence period. Alcohol drinking affected the content of the Sonic hedgehog (Shh) and Patched mRNAs only in the amygdala. In rats exposed to ethanol and receiving purmorphamine, the level of Shh mRNA in the amygdala correlated negatively with the time spent in the open arms of the elevated plus maze. Therefore, we demonstrated for the first time that alterations in the Hh cascade induced by administration of purmorphamine did not affect alcohol preference in voluntary alcohol drinking. It was suggested that Hh cascade is involved in the development of anxiety after alcohol withdrawal through specific changes in the Hh cascade components in the amygdala.

Therapeutic efficacy of Genistein in activation of neuronal AC/cAMP/CREB/PKA and mitochondrial ETC-Complex pathways in experimental model of autism: Evidence from CSF, blood plasma and brain analysis

Autism is a complex neurodevelopmental condition characterized by repetitive behaviors, impaired social communication, and various associated conditions such as depression and anxiety. Its multifactorial etiology includes genetic, environmental, dietary, and gastrointestinal contributions. Pathologically, Autism is linked to mitochondrial dysfunction, oxidative stress, neuroinflammation, and neurotransmitter imbalances involving GABA, glutamate, dopamine, and oxytocin. Propionic acid (PRPA) is a short-chain fatty acid produced by gut bacteria, influencing central nervous system functions. Elevated PRPA levels can exacerbate Autism-related symptoms by disrupting metabolic processes and crossing the blood-brain barrier. Our research investigates the neuroprotective potential of Genistein (GNT), an isoflavone compound with known benefits in neuropsychiatric and neurodegenerative disorders, through modulation of the AC/cAMP/CREB/PKA signaling pathway and mitochondrial ETC complex (I-IV) function. In silico analyses revealed GNT's high affinity for these targets. Subsequent in vitro and in vivo experiments using a PRPA-induced rat model of autism demonstrated that GNT (40 and 80 mg/kg., orally) significantly improves locomotion, neuromuscular coordination, and cognitive functions in PRPA-treated rodents. Behavioral assessments showed reduced immobility in the forced swim test, enhanced Morris water maze performance, and restored regular locomotor activity. On a molecular level, GNT restored levels of key signaling molecules (AC, cAMP, CREB, PKA) and mitochondrial complexes (I-V), disrupted by PRPA exposure. Additionally, GNT reduced neuroinflammation and apoptosis, normalized neurotransmitter levels, and improved the complete blood count profile. Histopathological analyses confirmed that GNT ameliorated PRPA-induced brain injuries, restored normal brain morphology, reduced demyelination, and promoted neurogenesis. The study supports GNT's potential in autism treatment by modulating neural pathways, reducing inflammation, and restoring neurotransmitter balance.

Synthesis and Neurobehavioral Evaluation of a Potent Multitargeted Inhibitor for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) poses a significant health challenge worldwide, affecting millions of individuals, and projected to increase further as the global population ages. Current pharmacological interventions primarily target acetylcholine deficiency and amyloid plaque formation, but offer limited efficacy and are often associated with adverse effects. Given the multifactorial nature of AD, there is a critical need for novel therapeutic approaches that simultaneously target multiple pathological pathways. Targeting key enzymes involved in AD pathophysiology, such as acetylcholinesterase, butyrylcholinesterase, beta-site APP cleaving enzyme 1 (BACE1), and gamma-secretase, is a potential strategy to mitigate disease progression. To this end, our research group has conducted comprehensive in silico screening to identify some lead compounds, including IQ6 (SSZ), capable of simultaneously inhibiting the enzymes mentioned above. Building upon this foundation, we synthesized SSZ, a novel multitargeted ligand/inhibitor to address various pathological mechanisms underlying AD. Chemically, SSZ exhibits pharmacological properties conducive to AD treatment, featuring pyrrolopyridine and N-cyclohexyl groups. Preclinical experimental evaluation of SSZ in AD rat model showed promising results, with notable improvements in behavioral and cognitive parameters. Specifically, SSZ treatment enhanced locomotor activity, ameliorated gait abnormalities, and improved cognitive function compared to untreated AD rats. Furthermore, brain morphological analysis demonstrated the neuroprotective effects of SSZ, attenuating Aβ-induced neuronal damage and preserving brain morphology. Combined treatment of SSZ and conventional drugs (DON and MEM) showed synergistic effects, suggesting a potential therapeutic strategy for AD management. Overall, our study highlights the efficacy of multitargeted ligands like SSZ in combating AD by addressing the complex etiology of the disease. Further research is needed to elucidate the full therapeutic potential of SSZ and the exploration of similar compounds in clinical settings, offering hope for an effective AD treatment in the future.

Purmorphamine, a Smo-Shh/Gli Activator, Promotes Sonic Hedgehog-Mediated Neurogenesis and Restores Behavioural and Neurochemical Deficits in Experimental Model of Multiple Sclerosis

Multiple sclerosis (MS) is a pathological condition characterized by the demyelination of nerve fibers, primarily attributed to the destruction of oligodendrocytes and subsequent motor neuron impairment. Ethidium bromide (EB) is a neurotoxic compound that induces neuronal degeneration, resulting in demyelination and symptoms resembling those observed in experimental animal models of multiple sclerosis (MS). The neurotoxic effects induced by EB in multiple sclerosis (MS) are distinguished by the death of oligodendrocytes, degradation of myelin basic protein (MBP), and deterioration of axons. Neurological complications related to MS have been linked to alterations in the signaling pathway known as smo-shh. Purmorphine (PUR) is a semi-synthetic compound that exhibits potent Smo-shh agonistic activity. It possesses various pharmacological properties, including antioxidant, anti-inflammatory, anti-apoptotic, and neuromodulatory effects. Hence, the current investigation was conducted to assess the neuroprotective efficacy of PUR (at doses of 5 and 10 mg/kg, administered intraperitoneally) both individually and in conjunction with Fingolimod (FING) (at a dose of 0.5 mg/kg, administered intraperitoneally) in the experimental model of MS induced by EB. The administration of EB was conducted via the intracerebropeduncle route (ICP) over a period of seven days in the brain of rats. The Wistar rats were allocated into six groups using randomization, each consisting of eight rats (n = 8 per group). The experimental groups in this study were categorized as follows: (I) Sham Control, (II) Vehicle Control, (III) PUR per se, (IV) EB, (V) EB + PUR5, (VI) EB + PUR10, (VII) EB + FING 0.5, and (VIII) EB + PUR10 + FING 0.5. On the final day of the experimental timeline, all animal subjects were euthanized, and subsequent neurochemical estimations were conducted on cerebrospinal fluid, blood plasma, and brain tissue samples. In addition, we conducted neurofilament (NFL) analysis and histopathological examination. We utilized the luxol myelin stain to understand better the degeneration associated with MS and its associated neurological complications. The findings of our study indicate that the activation of SMO-Shh by PUR has a mitigating effect on neurobehavioral impairments induced by EB, as well as a restorative effect on cellular and neurotransmitter abnormalities in an experimental model of MS.

Modulation of neural circuits by melatonin in neurodegenerative and neuropsychiatric disorders

Neurodegenerative and neuropsychiatric disorders are two broad categories of neurological disorders characterized by progressive impairments in movement and cognitive functions within the central and peripheral nervous systems, and have emerged as a significant cause of mortality. Oxidative stress, neuroinflammation, and neurotransmitter imbalances are recognized as prominent pathogenic factors contributing to cognitive deficits and neurobehavioral anomalies. Consequently, preventing neurodegenerative and neuropsychiatric diseases has surfaced as a pivotal challenge in contemporary public health. This review explores the investigation of neurodegenerative and neuropsychiatric disorders using both synthetic and natural bioactive compounds. A central focus lies on melatonin, a neuroregulatory hormone secreted by the pineal gland in response to light-dark cycles. Melatonin, an amphiphilic molecule, assumes multifaceted roles, including scavenging free radicals, modulating energy metabolism, and synchronizing circadian rhythms. Noteworthy for its robust antioxidant and antiapoptotic properties, melatonin exhibits diverse neuroprotective effects. The inherent attributes of melatonin position it as a potential key player in the pathophysiology of neurological disorders. Preclinical and clinical studies have demonstrated melatonin's efficacy in alleviating neuropathological symptoms across neurodegenerative and neuropsychiatric conditions (depression, schizophrenia, bipolar disorder, and autism spectrum disorder). The documented neuroprotective prowess of melatonin introduces novel therapeutic avenues for addressing neurodegenerative and psychiatric disorders. This comprehensive review encompasses many of melatonin's applications in treating diverse brain disorders. Despite the strides made, realizing melatonin's full neuroprotective potential necessitates further rigorous clinical investigations. By unravelling the extended neuroprotective benefits of melatonin, future studies promise to deepen our understanding and augment the therapeutic implications against neurological deficits.

A bibliometric analysis of autism spectrum disorder signaling pathways research in the past decade

Background

This study employs bibliometric methods to comprehensively understand the fundamental structure of research about Autism Spectrum Disorder (ASD) Signaling Pathways by examining key indicators such as nations, institutions, journals, authors, and keywords.

Methodology

We utilized the WoScc database to retrieve literature relevant to ASD Signaling Pathways published between 2013 and 2023. Through visual analysis and tools like CiteSpace and VosViewer, we explored nations, institutions, journals, authors, and keywords, thereby constructing relevant networks.

Results

26 The study encompasses 1,396 articles, revealing a consistent increase in publications. The United States, China, and Germany are leading nations in this literature. Regarding research institutions, the University of California system and Eric Klann have garnered significant attention due to their substantial contributions to the field of ASD Signaling Pathways. Most relevant research is published in the journal "Molecular Autism." Research interests are concentrated across various themes, including "elevating neuronal β-catenin levels," "Tunisian children," "Fmr1 knockout (KO) mice," "de novo mutations," "autistic children," "local translation," "propionic acid-induced mouse models," "neurosystems," "glucose metabolism," and "neuronal migration." Future research may emphasize exploring aspects such as gut microbiota, genes, stress, maternal immune activation, memory, and neurodevelopmental disorders of ASD.

Conclusion

This study, through bibliometric analysis of key indicators such as nations, institutions, journals, authors, and keywords, provides a comprehensive overview of the current state of research on ASD Signaling Pathways. These investigations predominantly focus on molecular mechanisms, animal model studies, population-based research, and the structure and function of neurosystems. Future research directions are also clearly proposed. First, in-depth research on the genes and neurodevelopmental disorders associated with ASD will continue to reveal the genetic basis and provide support for precise treatments. At the same time, attention to the gut microbiota will help explore its association with ASD, which may provide clues for new treatments. In addition, the relationship between stress and ASD will become the focus of research to understand better the emotional and behavioral characteristics of ASD patients in stressful situations. Maternal immune activation will also be further studied to explore how environmental factors influence the risk and development of ASD. Finally, a deeper understanding of the cognitive functions of patients with ASD, especially memory and learning, will help develop individualized treatment strategies to improve patients' quality of life. These directions will work together and are expected to provide a more comprehensive understanding of Signaling Pathways research in ASD and provide new ideas and opportunities for future intervention and treatment.

Matrine mediated neuroprotective potential in experimental multiple sclerosis: Evidence from CSF, blood markers, brain samples and in-silico investigations

Multiple sclerosis (MS) is a debilitating, inflammatory, and demyelinating disease of the central nervous system influenced by environmental and genetic factors. Around 2.8 million people worldwide are affected by MS due to its challenging diagnosis and treatment. Our study investigates the role of the JAK/STAT and PPAR-gamma signaling pathways in the progression of multiple sclerosis. Inflammation and demyelination can be caused by dysregulation of these pathways. Modulating the STAT-3, mTOR, and PPAR-gamma signaling pathways may offer therapeutic potential for multiple sclerosis. Matrine (40 and 80 mg/kg, i.p.), a quinolizidine alkaloid derived from Sophora flavescens, has been investigated for its therapeutic potential in our laboratory. Matrine has been studied for its neuroprotective effect in neurodegenerative diseases. It inhibits inflammatory responses and promotes regeneration of damaged myelin sheaths, indicating its potential efficacy in treating multiple sclerosis. Matrine exerts its neuroprotective effect by inhibiting STAT-3 and mTOR and promoting PPAR-gamma expression.GW9662, a PPAR-gamma antagonist (2 mg/kg, i.p.), was administered to evaluate the involvement of PPAR-gamma and to compare the efficacy of matrine's potential neuroprotective effect. Matrine's interaction with the STAT-3, mTOR, and PPAR-gamma pathways in multiple Sclerosis was also validated and confirmed through insilico investigation. In addition, matrine altered the CBC profile, intensifying the clinical presentation of multiple sclerosis. In addition, we evaluated the diagnostic potential of various biological samples, including CSF, blood plasma, and brain homogenates (striatum, cortex, hippocampus, and midbrain). These samples were used to evaluate the neurochemical changes caused by neurobehavioral alterations during the progression of multiple sclerosis. These results indicate that matrine treatment ameliorated multiple sclerosis and that the mechanism underlying these effects may be closely related to the modulation of the STAT-3/mTOR/PPAR-gamma signaling pathway.

Melatonin-mediated IGF-1/GLP-1 activation in experimental OCD rats: Evidence from CSF, blood plasma, brain and in-silico investigations

Obsessive-compulsive disorder (OCD) is a neuropsychiatric condition characterized by intrusive, repetitive thoughts and behaviors. Our study uses a validated 8-OH-DPAT-induced experimental model of OCD in rodents. We focus on the modulatory effects of Insulin-like growth factor-1 (IGF-1) and glucagon-like peptide-1 (GLP-1), which are linked to neurodevelopment and survival. Current research investigates melatonin, a molecule with neuroprotective properties and multiple functions. Melatonin has beneficial effects on various illnesses, including Alzheimer's, Parkinson's, and depression, indicating its potential efficacy in treating OCD. In the present study, we employed two doses of melatonin, 5 mg/kg and 10 mg/kg, demonstrating a dose-dependent effect on 8-OH-DPAT-induced rat changes. In addition, the melatonin antagonist luzindole 5 mg/kg was utilized to compare and validate the efficacy of melatonin. In-silico studies alsocontribute to understanding the activation of IGF-1/GLP-1 pathways by melatonin. Current research indicates restoring neurochemical measurements on various biological samples (brain homogenates, CSF, and blood plasma) and morphological and histological analyses. In addition, the current research seeks to increase understanding of OCD and investigate potential new treatment strategies. Therefore, it is evident from the aforementioned research that the protective effect of melatonin can serve as a strong basis for developing a new OCD treatment by upregulating IGF-1 and GLP-1 levels. The primary focus of current study revolves around the examination of melatonin as an activator of IGF-1/GLP-1, with the aim of potentially mitigating behavioral, neurochemical, and histopathological abnormalities in an experimental model of obsessive-compulsive disorder caused by 8-OH-DPAT in adult Wistar rats.

Acetyl-11-keto-beta boswellic acid(AKBA) modulates CSTC-pathway by activating SIRT-1/Nrf2-HO-1 signalling in experimental rat model of obsessive-compulsive disorder: Evidenced by CSF, blood plasma and histopathological alterations

Obsessive-Compulsive disorder (OCD) is a long-term and persistent mental illness characterised by obsessive thoughts and compulsive behaviours. Numerous factors can contribute to the development or progression of OCD. These factors may result from the dysregulation of multiple intrinsic cellular pathways, including SIRT-1, Nrf2, and HO-1. Inhibitors of selective serotonin reuptake (SSRIs) are effective first-line treatments for OCD. In our ongoing research, we have investigated the role of SIRT-1, Nrf2, and HO-1, as well as the neuroprotective potential of Acetyl-11-keto-beta boswellic acid (AKBA) against behavioural and neurochemical changes in rodents treated with 8-OH-DPAT. In addition, the effects of AKBA were compared to those of fluvoxamine (FLX), a standard OCD medication. Injections of 8-OH-DPAT into the intra-dorso raphe nuclei (IDRN) of rats for seven days induced repetitive and compulsive behaviour accompanied by elevated oxidative stress, inflammatory processes, apoptosis, and neurotransmitter imbalances in CSF, blood plasma, and brain samples. Chronic administration of AKBA at 50 mg/kg and 100 mg/kg p.o. restored histopathological alterations in the cortico-striatal-thalamo-cortical (CSTC) pathway, including the cerebral cortex, striatum, and hippocampal regions. Our investigation revealed that when AKBA and fluvoxamine were administered together, the alterations were restored to a greater degree than when administered separately. These findings demonstrate that the neuroprotective effect of AKBA can serve as an effective basis for developing a novel OCD treatment.

The role of Smo-Shh/Gli signaling activation in the prevention of neurological and ageing disorders

Sonic hedgehog (Shh) signaling is an essential central nervous system (CNS) pathway involved during embryonic development and later life stages. Further, it regulates cell division, cellular differentiation, and neuronal integrity. During CNS development, Smo-Shh signaling is significant in the proliferation of neuronal cells such as oligodendrocytes and glial cells. The initiation of the downstream signalling cascade through the 7-transmembrane protein Smoothened (Smo) promotes neuroprotection and restoration during neurological disorders. The dysregulation of Smo-Shh is linked to the proteolytic cleavage of GLI (glioma-associated homolog) into GLI3 (repressor), which suppresses target gene expression, leading to the disruption of cell growth processes. Smo-Shh aberrant signalling is responsible for several neurological complications contributing to physiological alterations like increased oxidative stress, neuronal excitotoxicity, neuroinflammation, and apoptosis. Moreover, activating Shh receptors in the brain promotes axonal elongation and increases neurotransmitters released from presynaptic terminals, thereby exerting neurogenesis, anti-oxidation, anti-inflammatory, and autophagy responses. Smo-Shh activators have been shown in preclinical and clinical studies to help prevent various neurodegenerative and neuropsychiatric disorders. Redox signalling has been found to play a critical role in regulating the activity of the Smo-Shh pathway and influencing downstream signalling events. In the current study ROS, a signalling molecule, was also essential in modulating the SMO-SHH gli signaling pathway in neurodegeneration. As a result of this investigation, dysregulation of the pathway contributes to the pathogenesis of various neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD).Thus, Smo-Shh signalling activators could be a potential therapeutic intervention to treat neurocomplications of brain disorders.

Incomplete hippocampal inversion in patients with mutations in genes involved in sonic hedgehog signaling

Sonic hedgehog (Shh) signaling pathways are known to play an important role in the morphological development of the hippocampus in vivo, but their actual roles in humans have not been clarified. Hypothalamic hamartoma (HH) is known to be associated with germline or somatic gene mutations of Shh signaling. We hypothesized that patients with HH and mutations of Shh-related genes also show hippocampal maldevelopment and an abnormal hippocampal infolding angle (HIA). We analyzed 45 patients (age: 1-37 years) with HH who underwent stereotactic radiofrequency thermocoagulation and found Shh-related gene mutations in 20 patients. In addition, 44 pediatric patients without HH (age: 2-25 years) who underwent magnetic resonance imaging (MRI) examinations under the same conditions during the same period were included in this study as a control group. HIA evaluated on MRI was compared between patients with gene mutations and the control group. The median HIA at the cerebral peduncle slice in patients with the gene mutation was 74.36° on the left and 76.11° on the right, and these values were significantly smaller than the corresponding values in the control group (80.46° and 80.56°, respectively, p < 0.01). Thus, mutations of Shh-related genes were correlated to incomplete hippocampal inversion. The HIA, particularly at the cerebral peduncle slice, is a potential indicator of abnormalities of the Shh-signaling pathway.

4-hydroxyisoleucine mediated IGF-1/GLP-1 signalling activation prevents propionic acid-induced autism-like behavioural phenotypes and neurochemical defects in experimental rats

Autism is a neuropsychiatric disorder characterized by a neurotransmitter imbalance that impairs neurodevelopment processes. Autism development is marked by communication difficulties, poor socio-emotional health, and cognitive impairment. Insulin-like growth factor-1 (IGF-1) and glucagon-like growth factor-1 (GLP-1) are responsible for regular neuronal growth and homeostasis. Autism progression has been linked to dysregulation of IGF-1/GLP-1 signalling. 4-hydroxyisoleucine (HI), a pharmacologically active amino acid produced from Trigonella foenum graecum, works as an insulin mimic and has neuroprotective properties. The GLP-1 analogue liraglutide (LRG) was employed in our investigation to compare the efficacy of 4-HI in autism prevention. The current study explores the protective effects of 4-HI 50 and 100 mg/kg orally on IGF-1/GLP-1 signalling activation in a PPA-induced experimental model of autism. Propionic acid (PPA) injections to rats by intracerebroventricular (ICV) route for the first 11 days of the experiment resulted in autism-like neurobehavioral, neurochemical, gross morphological, and histopathological abnormalities. In addition, we investigated the dose-dependent neuroprotective effects of 4-HI on the levels of several neurotransmitters and neuroinflammatory cytokines in rat brain homogenate and blood plasma. Neuronal apoptotic and anti-oxidant cellular markers were also studied in blood plasma and brain homogenate samples. Furthermore, the luxol fast blue (LFB) staining results demonstrated significant demyelination in the brains of PPA-induced rats reversed by 4-HI treatment. Rats were assessed for spontaneous locomotor impairments, neuromuscular coordination, stress-like behaviour, learning, and memory to assess neurobehavioral abnormalities. The administration of 4-HI and LRG significantly reversed the behavioural, gross and histological abnormalities in the PPA-treated rat brains. After treatment with 4-HI and LRG, LFB-stained photomicrographs of PPA-treated rats' brains demonstrated the recovery of white matter loss. Our findings indicate that 4-HI protects neurons in rats with autism by enhancing the IGF-1 and GLP-1 protein levels.

Role of Sonic Hedgehog Signaling Activation in the Prevention of Neurological Abnormalities Associated with Obsessive-Compulsive Disorder

The smoothened sonic hedgehog (Smo-Shh) pathway is one mechanism that influences neurogenesis, including brain cell differentiation and development during childhood. Shh signaling dysregulation leads to decreased target gene transcription, which contributes to increased neuronal excitation, apoptosis, and neurodegeneration, eventually leading to neurological deficits. Neuropsychiatric disorders such as OCD and related neurological dysfunctions are characterized by neurotransmitter imbalance, neuroinflammation, oxidative stress, and impaired neurogenesis, disturbing the cortico-striato-thalamo-cortical (CSTC) link neuronal network. Despite the availability of several treatments, such as selective serotonin reuptake inhibitors, some individuals may not benefit much from them. Several trials on the use of antipsychotics in the treatment of OCD have also produced inadequate findings. This evidence-based review focuses on a potential pharmacological approach to alleviating OCD and associated neuronal deficits by preventing neurochemical alterations, in which sonic hedgehog activators are neuroprotective, lowering neuronal damage while increasing neuronal maintenance and survival. As a result, stimulating SMO-Shh via its potential activators may have neuroprotective effects on neurological impairment associated with OCD. This review investigates the link between SMO-Shh signaling and the neurochemical abnormalities associated with the progression of OCD and associated neurological dysfunctions. Role of Smo-Shh signaling in serotonergic neurogenesis and in maintaining their neuronal identity. The Shh ligand activates two main transcriptional factors known as Foxa2 and Nkx2.2, which again activates another transcriptional factor, GATA (GATA2 and GATA3), in post mitotic precursor cells of serotonergic neurons-following increased expression of Pet-1 and Lmx1b after GATA regulates the expression of many serotonergic enzymes such as TPH2, SERT, VMAT, slc6a4, Htr1a, Htr1b (Serotonin receptor enzymes), and MAO that regulate and control the release of serotonin and maintain their neuronal identity after their maturation. Abbreviation: Foxa2: Forkhead box; GATA: Globin transcription factor; Lmx1b: LIM homeobox transcription factor 1 beta; TPH2: Tryptophan hydroxylase 2; Htr1a: Serotonin receptor 1a; Htr1b: Serotonin receptor 1b; SERT: Serotonin transporter; VMAT: Vesicular monoamine transporter; MAO: Monoamine oxidase.

Effect of Natural Adenylcyclase/cAMP/CREB Signalling Activator Forskolin against Intra-Striatal 6-OHDA-Lesioned Parkinson's Rats: Preventing Mitochondrial, Motor and Histopathological Defects

Parkinson's disease (PD) is characterised by dopaminergic neuronal loss in the brain area. PD is a complex disease that deteriorates patients' motor and non-motor functions. In experimental animals, the neurotoxin 6-OHDA induces neuropathological, behavioural, neurochemical and mitochondrial abnormalities and the formation of free radicals, which is related to Parkinson-like symptoms after inter-striatal 6-OHDA injection. Pathological manifestations of PD disrupt the cAMP/ATP-mediated activity of the transcription factor CREB, resulting in Parkinson's-like symptoms. Forskolin (FSK) is a direct AC/cAMP/CREB activator isolated from Coleus forskohlii with various neuroprotective properties. FSK has already been proven in our laboratory to directly activate the enzyme adenylcyclase (AC) and reverse the neurodegeneration associated with the progression of Autism, Multiple Sclerosis, ALS, and Huntington's disease. Several behavioural paradigms were used to confirm the post-lesion effects, including the rotarod, open field, grip strength, narrow beam walk (NBW) and Morris water maze (MWM) tasks. Our results were supported by examining brain cellular, molecular, mitochondrial and histopathological alterations. The FSK treatment (15, 30 and 45 mg/kg, orally) was found to be effective in restoring behavioural and neurochemical defects in a 6-OHDA-induced experimental rat model of PD. As a result, the current study successfully contributes to the investigation of FSK's neuroprotective role in PD prevention via the activation of the AC/cAMP/PKA-driven CREB pathway and the restoration of mitochondrial ETC-complex enzymes.

Beta-Boswellic Acid Reverses 3-Nitropropionic Acid-Induced Molecular, Mitochondrial, and Histopathological Defects in Experimental Rat Model of Huntington's Disease

Huntington's disease (HD) is distinguished by a triple repeat of CAG in exon 1, an increase in poly Q in the Htt gene, and a loss of GABAergic medium spiny neurons (MSN) in the striatum and white matter of the cortex. Mitochondrial ETC-complex dysfunctions are involved in the pathogenesis of HD, including neuronal energy loss, synaptic neurotrophic decline, neuronal inflammation, apoptosis, and grey and white matter destruction. A previous study has demonstrated that beta Boswellic acid (β-BA), a naturally occurring phytochemical, has several neuroprotective properties that can reduce pathogenic factors associated with various neurological disorders. The current investigation aimed to investigate the neuroprotective potential of β-BA at oral doses of 5, 10, and 15 mg/kg alone, as well as in conjunction with the potent antioxidant vitamin E (8 mg/kg, orally) in 3-NP-induced experimental HD rats. Adult Wistar rats were separated into seven groups, and 3-NP, at a dose of 10 mg/kg, was orally administered to each group of adult Wistar rats beginning on day 1 and continuing through day 14. The neurotoxin 3-NP induces neurodegenerative, g, neurochemical, and pathological alterations in experimental animals. Continuous injection of 3-NP, according to our results, aggravated HD symptoms by suppressing ETC-complex-II, succinate dehydrogenase activity, and neurochemical alterations. β-BA, when taken with vitamin E, improved behavioural dysfunctions such as neuromuscular and motor impairments, as well as memory and cognitive abnormalities. Pharmacological treatments with β-BA improved and restored ETC complexes enzymes I, II, and V levels in brain homogenates. β-BA treatment also restored neurotransmitter levels in the brain while lowering inflammatory cytokines and oxidative stress biomarkers. β-BA's neuroprotective potential in reducing neuronal death was supported by histopathological findings in the striatum and cortex. As a result, the findings of this research contributed to a better understanding of the potential role of natural phytochemicals β-BA in preventing neurological illnesses such as HD.

Forskolin, an Adenylcyclase/cAMP/CREB Signaling Activator Restoring Myelin-Associated Oligodendrocyte Destruction in Experimental Ethidium Bromide Model of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic neurodegenerative disease marked by oligodendrocyte loss, which results in central neuronal demyelination. AC/cAMP/CREB signaling dysregulation is involved in the progression of MS, including mitochondrial dysfunctions, reduction in nerve growth factors, neuronal inflammation, apoptosis, and white matter degeneration. Our previous research has shown that Forskolin (FSK), a naturally occurring direct adenylyl cyclase (AC)/cAMP/CREB activator, has neuroprotective potential to alleviate pathogenic factors linked with numerous neurological abnormalities. The current study intends to explore the neuroprotective potential of FSK at doses of 40 mg/kg and 60 mg/kg alone, as well as in combination with conventional medicines, such as Fingolimod (FNG), Donepezil (DON), Memantine (MEM), and Simvastatin (SIM) in EB-induced demyelinated experimental MS rats. Adult Wistar rats were divided into nine groups, and EB was infused stereotaxically in the rat brain’s intracerebropeduncle (ICP) area. Chronic gliotoxin EB treatment results in demyelination as well as motor and cognitive dysfunctions. FSK, combined with standard medications, improves behavioral dysfunctions, such as neuromuscular and motor deficits and memory and cognitive abnormalities. Following pharmacological treatments improved remyelination by enhancing myelin basic protein and increasing AC, cAMP, and CREB levels in brain homogenates. Furthermore, FSK therapy restored brain mitochondrial-ETC complex enzymes and neurotransmitter levels while decreasing inflammatory cytokines and oxidative stress markers. The Luxol fast blue (LFB) stain results further indicate FSK’s neuroprotective potential in preventing oligodendrocyte death. Therefore, the results of these studies contribute to a better understanding of the possible role that natural phytochemicals FSK could have in preventing motor neuron diseases, such as multiple sclerosis.

Activating SIRT-1 Signalling with the Mitochondrial-CoQ10 Activator Solanesol Improves Neurobehavioral and Neurochemical Defects in Ouabain-Induced Experimental Model of Bipolar Disorder

Bipolar disorder (BD) is a chronic mental illness characterized by mood fluctuations that range from depressive lows to manic highs. Several studies have linked the downregulation of SIRT-1 (silent mating type information regulation-2 homologs) signaling to the onset of BD and other neurological dysfunctions. This research aimed to look into the neuroprotective potential of Solanesol (SNL) in rats given ICV-Ouabain injections, focusing on its effect on SIRT-1 signaling activation in the brain. Ouabain, found in hypothalamic and medullary neurons, is an endogenous inhibitor of brain Na⁺/K⁺ ATPase. The inhibition of brain Na⁺/K⁺ ATPase by Ouabain may also result in changes in neurotransmission within the central nervous system. SNL is a Solanaceae family active phytoconstituent produced from the plant Nicotiana tabacum. SNL is used as a precursor for the production of CoQ10 (Coenzyme Q10), a powerful antioxidant and neuroprotective compound. In the current study, lithium (Li), an important mood stabilizer drug, was used as a control. This study looked at the neuroprotective potential of SNL at dosages of 40 and 80 mg/kg in ICV-OUA injections that caused BD-like neurobehavioral and neurochemical defects in Wistar rats. Wistar rats were placed into eight groups (n = 6) and administered 1 mM/0.5 µL ICV-OUA injections for three days. Neurochemical assessments were done in rat brain homogenates, CSF, and blood plasma samples at the end of the experiment protocol schedule. Long-term SNL and lithium administration have been shown to decrease the number of rearing and crossings and reduce time spent in the center, locomotor activities, and immobility time. Solansesol treatment gradually raises the amount of Na⁺/K⁺ ATPase, limiting the severity of behavioural symptoms. These findings also revealed that SNL increases the levels of SIRT-1 in CSF, blood plasma, and brain homogenate samples. Moreover, in rat brain homogenates and blood plasma samples, SNL modulates apoptotic markers such as Caspase-3, Bax (pro-apoptotic), and Bcl-2 (anti-apoptotic). Mitochondrial-ETC complex enzymes, including complex-I, II, IV, V, and CoQ10, were also restored following long-term SNL treatment. Furthermore, SNL lowered inflammatory cytokines (TNF-α, IL-1β) levels while restoring neurotransmitter levels (serotonin, dopamine, glutamate, and acetylcholine) and decreasing oxidative stress markers. Histological examinations also validated Solanesol’s protective effect. As a result, our findings suggest that SNL, as a SIRT-1 signalling activator, may be a promising therapeutic approach for BD-like neurological dysfunctions.

PI3K/AKT/mTOR signalling inhibitor chrysophanol ameliorates neurobehavioural and neurochemical defects in propionic acid-induced experimental model of autism in adult rats

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder marked by social and communication deficits as well as repetitive behaviour. Several studies have found that overactivation of the PI3K/AKT/mTOR signalling pathways during brain development plays a significant role in autism pathogenesis. Overexpression of the PI3K/AKT/mTOR signalling pathway causes neurological disorders by increasing cell death, neuroinflammation, and oxidative stress. Chrysophanol, also known as chrysophanic acid, is a naturally occurring chemical obtained from the plant Rheum palmatum. This study aimed to examine the neuroprotective effect of CPH on neurobehavioral, molecular, neurochemical, and gross pathological alterations in ICV-PPA induced experimental model of autism in adult rats. The effects of ICV-PPA on PI3K/AKT/mTOR downregulation in the brain were studied in autism-like rats. Furthermore, we investigated how CPH affected myelin basic protein (MBP) levels in rat brain homogenate and apoptotic biomarkers such as caspase-3, Bax, and Bcl-2 levels in rat brain homogenate and blood plasma samples. Rats were tested for behavioural abnormalities such as neuromuscular dysfunction using an actophotometer, motor coordination using a beam crossing task (BCT), depressive behaviour using a forced swim test (FST), cognitive deficiency, and memory consolidation using a Morris water maze (MWM) task. In PPA-treated rats, prolonged oral CPH administration from day 12 to day 44 of the experimental schedule reduces autistic-like symptoms. Furthermore, in rat brain homogenates, blood plasma, and CSF samples, cellular, molecular, and cell death markers, neuroinflammatory cytokines, neurotransmitter levels, and oxidative stress indicators were investigated. The recent findings imply that CPH also restores abnormal neurochemical levels and may prevent autism-like gross pathological alterations, such as demyelination volume, in the rat brain.

Nrf2/HO-1 Signaling Stimulation through Acetyl-11-Keto-Beta-Boswellic Acid (AKBA) Provides Neuroprotection in Ethidium Bromide-Induced Experimental Model of Multiple Sclerosis

Multiple sclerosis (MS) is a severe immune-mediated neurological disease characterized by neuroinflammation, demyelination, and axonal degeneration in the central nervous system (CNS). This is frequently linked to motor abnormalities and cognitive impairments. The pathophysiological hallmarks of MS include inflammatory demyelination, axonal injury, white matter degeneration, and the development of CNS lesions that result in severe neuronal degeneration. Several studies suggested downregulation of nuclear factor erythroid-2-related factor-2 (Nrf2)/Heme oxygenase-1 (HO-1) signaling is a causative factor for MS pathogenesis. Acetyl-11-keto-β-boswellic acid (AKBA) is an active pentacyclictriterpenoid obtained from Boswellia serrata, possessing antioxidant and anti-inflammatory properties. The present study explores the protective potential of AKBA on behavioral, molecular, neurochemical, and gross pathological abnormalitiesandhistopathological alterations by H&E and LFB staining techniques in an experimental model of multiple sclerosis, emphasizing the increase inNrf2/HO-1 levels in the brain. Moreover, we also examine the effect of AKBA on the intensity of myelin basic protein (MBP) in CSF and rat brain homogenate. Specific apoptotic markers (Bcl-2, Bax, andcaspase-3) were also estimated in rat brain homogenate. Neuro behavioralabnormalities in rats were examined using an actophotometer, rotarod test, beam crossing task (BCT),and Morris water maze (MWM). AKBA 50 mg/kg and 100 mg/kg were given orally from day 8 to 35 to alleviate MS symptoms in the EB-injected rats. Furthermore, cellular, molecular, neurotransmitter, neuroinflammatory cytokine, and oxidative stress markers in rat whole brain homogenate, blood plasma, and cerebral spinal fluid were investigated. This study shows that AKBA upregulates the level of antioxidant proteins such as Nrf2 and HO-1 in the rat brain. AKBA restores altered neurochemical levels, potentially preventing gross pathological abnormalities during MS progression.

Activation of IGF-1/GLP-1 Signalling via 4-Hydroxyisoleucine Prevents Motor Neuron Impairments in Experimental ALS-Rats Exposed to Methylmercury-Induced Neurotoxicity

Amyotrophic lateral sclerosis (ALS) is a severe adult motor neuron disease that causes progressive neuromuscular atrophy, muscle wasting, weakness, and depressive-like symptoms. Our previous research suggests that mercury levels are directly associated with ALS progression. MeHg+-induced ALS is characterised by oligodendrocyte destruction, myelin basic protein (MBP) depletion, and white matter degeneration, leading to demyelination and motor neuron death. The selection of MeHg+ as a potential neurotoxicant is based on our evidence that it has been connected to the development of ALS-like characteristics. It causes glutamate-mediated excitotoxicity, calcium-dependent neurotoxicity, and an ALS-like phenotype. Dysregulation of IGF-1/GLP-1 signalling has been associated with ALS progression. The bioactive amino acid 4-hydroxyisoleucine (HI) from Trigonella foenum graecum acts as an insulin mimic in rodents and increases insulin sensitivity. This study examined the neuroprotective effects of 4-HI on MeHg+-treated adult Wistar rats with ALS-like symptoms, emphasising brain IGF1/GLP-1 activation. Furthermore, we investigated the effect of 4-HI on MBP levels in rat brain homogenate, cerebrospinal fluid (CSF), blood plasma, and cell death indicators such as caspase-3, Bax, and Bcl-2. Rats were assessed for muscular strength, locomotor deficits, depressed behaviour, and spatial learning in the Morris water maze (MWM) to measure neurobehavioral abnormalities. Doses of 4-HI were given orally for 42 days in the MeHg+ rat model at 50 mg/kg or 100 mg/kg to ameliorate ALS-like neurological dysfunctions. Additionally, neurotransmitters and oxidative stress markers were examined in rat brain homogenates. Our findings suggest that 4-HI has neuroprotective benefits in reducing MeHg+-induced behavioural, neurochemical, and histopathological abnormalities in ALS-like rats exposed to methylmercury.

Effect of alpha-mangostin in the prevention of behavioural and neurochemical defects in methylmercury-induced neurotoxicity in experimental rats

Methylmercury (MeHg+) is a known neurotoxin that causes progressive motor neuron degeneration in the central nervous system. Axonal degeneration, oligodendrocyte degeneration, and myelin basic protein (MBP) deficits are among the neuropathological abnormalities caused by MeHg+ in amyotrophic lateral sclerosis (ALS). This results in demyelination and motor neuron death in both humans and animals. Previous experimental studies have confirmed that overexpression of the extracellular signalling regulated kinase (ERK1/2) signalling contributes to glutamate excitotoxicity, inflammatory response of microglial cells, and oligodendrocyte (OL) dysfunction that promotes myelin loss. Alpha-mangostin (AMG), an active ingredient obtained from the tree "Garcinia mangostana Linn," has been used in experimental animals to treat a variety of brain disorders, including Parkinson's and Huntington's disease memory impairment, Alzheimer's disease, and schizophrenia, including Parkinson's disease and Huntington's disease memory impairment, Alzheimer's disease, and schizophrenia. AMG has traditionally been used as an antioxidant, anti-inflammatory, and neuroprotective agent.Accordingly, we investigated the therapeutic potential of AMG (100 and 200 mg/kg) in experimental rats with methylmercury (MeHg+)-induced neurotoxicity. The neuroprotective effect of AMG on behavioural, cellular, molecular, and other gross pathological changes, such as histopathological alterations in MeHg+ -treated rat brains, is presented. The neurological behaviour of experimental rats was evaluated using a Morris water maze (MWM), open field test (OFT), grip strength test (GST), and force swim test (FST). In addition, we investigate AMG's neuroprotective effect by restoring MBP levels in cerebral spinal fluid and whole rat brain homogenate. The apoptotic, pro-inflammatory, and oxidative stress markers were measured in rat blood plasma samples and brain homogenate. According to the findings of this study, AMG decreases ERK-1/2 levels and modulates neurochemical alterations in rat brains, minimising MeHg+ -induced neurotoxicity.

Neuroprotective Effect of Chrysophanol as a PI3K/AKT/mTOR Signaling Inhibitor in an Experimental Model of Autologous Blood-induced Intracerebral Hemorrhage

OBJECTIVE

Intracerebral hemorrhage (ICH) refers to predominant, sporadic, and non-traumatic bleeding in the brain parenchyma. The PI3K/AKT/mTOR signaling pathway is an important signal transduction pathway regulated by enzyme-linked receptors and has many biological functions in mammals. It plays a key role in neuronal metabolism, gene expression regulation, and tissue homeostasis in the healthy and diseased brain.

METHODS

In the present study, the role of the PI3K/AKT/mTOR pathway inhibitor chrysophanol (CPH) (10 mg/kg and 20 mg/kg, orally) in the improvement of ICH-associated neurological defects in rats was investigated. Autologous blood (20 µL/5 min/unilateral/intracerebroventricular) mimics ICH-like defects involving cellular and molecular dysfunction and neurotransmitter imbalance. The current study also included various behavioral assessments to examine cognition, memory, and motor and neuromuscular coordination. The protein expression levels of PI3K, AKT, and mTOR as well as myelin basic protein and apoptotic markers, such as Bax, Bcl-2, and caspase-3, were examined using ELISA kits. Furthermore, the levels of various neuroinflammatory cytokines and oxidative stress markers were assessed. Additionally, the neurological severity score, brain water content, gross brain pathology, and hematoma size were used to indicate neurological function and brain edema.

RESULTS

CPH was found to be neuroprotective by restoring neurobehavioral alterations and significantly reducing the elevated PI3K, AKT, and mTOR protein levels, and modulating the apoptotic markers such as Bax, Bcl-2, and caspase-3 in rat brain homogenate. CPH substantially reduced the inflammatory cytokines like interleukin (IL)-1β, IL-6, and tumor necrosis factor-α. CPH administration restored the neurotransmitters GABA, glutamate, acetylcholine, dopamine, and various oxidative stress markers.

CONCLUSION

Our results show that CPH may be a promising therapeutic approach for overcoming neuronal damage caused by the overexpression of the PI3K/AKT/mTOR signaling pathway in ICH-induced neurological dysfunctions in rats.

Smo-Shh Agonist Purmorphamine Prevents Neurobehavioral and Neurochemical Defects in 8-OH-DPAT-Induced Experimental Model of Obsessive-Compulsive Disorder

Obsessive-compulsive disorder is a mental disorder characterized by repetitive, unwanted thoughts and behavior due to abnormal neuronal corticostriatal-thalamocortical pathway and other neurochemical changes. Purmorphamine is a smoothened-sonic-hedgehog agonist that has a protective effect against many neurological diseases due to its role in maintaining functional connectivity during CNS development and its anti-inflammatory and antioxidant properties. As part of our current research, we investigated the neuroprotective effects of PUR against behavioral and neurochemical changes in 8-hydroxy-2-(di-n-propylamino)-tetralin-induced obsessive-compulsive disorder in rats. Additionally, the effect of PUR was compared with the standard drug for OCD, i.e., fluvoxamine. The intra-dorsal raphe-nucleus injection of 8-OH-DPAT in rats for seven days significantly showed OCD-like repetitive and compulsive behavior along with increased oxidative stress, inflammation, apoptosis, as well as neurotransmitter imbalance. These alterations were dose-dependently attenuated by long-term purmorphamine treatment at 5 mg/kg and 10 mg/kg i.p. In this study, we assessed the level of various neurochemical parameters in different biological samples, including brain homogenate, blood plasma, and CSF, to check the drug’s effect centrally and peripherally. These effects were comparable to the standard oral treatment withfluvoxamine at 10 mg/kg. However, when fluvoxamine was given in combination with purmorphamine, there was a more significant restoration of these alterations than the individualtreatmentswithfluvoxamine and purmorphamine. All the above findings demonstrate that the neuroprotective effect of purmorphamine in OCD can be strong evidence for developing a new therapeutic target for treating and managing OCD.

Guggulsterone Mediated JAK/STAT and PPAR-Gamma Modulation Prevents Neurobehavioral and Neurochemical Abnormalities in Propionic Acid-Induced Experimental Model of Autism

Autism spectrum disorder is a neurodevelopmental disorder marked by repetitive behaviour, challenges in verbal and non-verbal communication, poor socio-emotional health, and cognitive impairment. An increased level of signal transducer and activator of transcription 3 (STAT3) and a decreased level of peroxisome proliferator-activated receptor (PPAR) gamma have been linked to autism pathogenesis. Guggulsterone (GST) has a neuroprotective effect on autistic conditions by modulating these signalling pathways. Consequently, the primary objective of this study was to examine potential neuroprotective properties of GST by modulating JAK/STAT and PPAR-gamma levels in intracerebroventricular propionic acid (ICV PPA) induced experimental model of autism in adult rats. In this study, the first 11 days of ICV-PPA injections in rats resulted in autism-like behavioural, neurochemical, morphological, and histopathological changes. The above modifications were also observed in various biological samples, including brain homogenate, CSF, and blood plasma. GST was also observed to improve autism-like behavioural impairments in autistic rats treated with PPA, including locomotion, neuromuscular coordination, depression-like behaviour, spatial memory, cognition, and body weight. Prolonged GST treatment also restored neurochemical deficits in a dose-dependent manner. Chronic PPA administration increased STAT3 and decreased PPAR gamma in autistic rat brain, CSF, and blood plasma samples, which were reversed by GST. GST also restored the gross and histopathological alterations in PPA-treated rat brains. Our results indicate the neuroprotective effects of GST in preventing autism-related behavioural and neurochemical alterations.

Neuroprotective Effect of Chrysophanol as a PI3K/AKT/mTOR Signaling Inhibitor in an Experimental Model of Autologous Blood-induced Intracerebral Hemorrhage

OBJECTIVE

Intracerebral hemorrhage (ICH) refers to predominant, sporadic, and non-traumatic bleeding in the brain parenchyma. The PI3K/AKT/mTOR signaling pathway is an important signal transduction pathway regulated by enzyme-linked receptors and has many biological functions in mammals. It plays a key role in neuronal metabolism, gene expression regulation, and tissue homeostasis in the healthy and diseased brain.

METHODS

In the present study, the role of the PI3K/AKT/mTOR pathway inhibitor chrysophanol (CPH) (10 mg/kg and 20 mg/kg, orally) in the improvement of ICH-associated neurological defects in rats was investigated. Autologous blood (20 µL/5 min/unilateral/intracerebroventricular) mimics ICH-like defects involving cellular and molecular dysfunction and neurotransmitter imbalance. The current study also included various behavioral assessments to examine cognition, memory, and motor and neuromuscular coordination. The protein expression levels of PI3K, AKT, and mTOR as well as myelin basic protein and apoptotic markers, such as Bax, Bcl-2, and caspase-3, were examined using ELISA kits. Furthermore, the levels of various neuroinflammatory cytokines and oxidative stress markers were assessed. Additionally, the neurological severity score, brain water content, gross brain pathology, and hematoma size were used to indicate neurological function and brain edema.

RESULTS

CPH was found to be neuroprotective by restoring neurobehavioral alterations and significantly reducing the elevated PI3K, AKT, and mTOR protein levels, and modulating the apoptotic markers such as Bax, Bcl-2, and caspase-3 in rat brain homogenate. CPH substantially reduced the inflammatory cytokines like interleukin (IL)-1β, IL-6, and tumor necrosis factor-α. CPH administration restored the neurotransmitters GABA, glutamate, acetylcholine, dopamine, and various oxidative stress markers.

CONCLUSION

Our results show that CPH may be a promising therapeutic approach for overcoming neuronal damage caused by the overexpression of the PI3K/AKT/mTOR signaling pathway in ICH-induced neurological dysfunctions in rats.

Contribution of Smoothened Receptor Signaling in GABAergic Neurotransmission and Chloride Homeostasis in the Developing Rodent Brain

In the early stages of the central nervous system growth and development, γ-aminobutyric acid (GABA) plays an instructive trophic role for key events including neurogenesis, migration, synaptogenesis, and network formation. These actions are associated with increased concentration of chloride ions in immature neurons [(Cl⁻)_i] that determines the depolarizing strength of ion currents mediated by GABA_A receptors, a ligand-gated Cl⁻ permeable ion channel. During neuron maturation the (Cl⁻)_i progressively decreases leading to weakening of GABA induced depolarization and enforcing GABA function as principal inhibitory neurotransmitter. A neuron restricted potassium-chloride co-transporter KCC2 is a key molecule governing Cl⁻ extrusion and determining the resting level of (Cl⁻)_i in developing and mature mammalian neurons. Among factors controlling the functioning of KCC2 and the maturation of inhibitory circuits, is Smoothened (Smo), the transducer in the receptor complex of the developmental protein Sonic Hedgehog (Shh). Too much or too little Shh-Smo action will have mirror effects on KCC2 stability at the neuron membrane, the GABA inhibitory strength, and ultimately on the newborn susceptibility to neurodevelopmental disorders. Both canonical and non-canonical Shh-Smo signal transduction pathways contribute to the regulation of KCC2 and GABAergic synaptic activity. In this review, we discuss the recent findings of the action of Shh-Smo signaling pathways on chloride ions homeostasis through the control of KCC2 membrane trafficking, and consequently on inhibitory neurotransmission and network activity during postnatal development.

Prophylactic Activation of Shh Signaling Attenuates TBI-Induced Seizures in Zebrafish by Modulating Glutamate Excitotoxicity through Eaat2a

Approximately 2 million individuals experience a traumatic brain injury (TBI) every year in the United States. Secondary injury begins within minutes after TBI, with alterations in cellular function and chemical signaling that contribute to excitotoxicity. Post-traumatic seizures (PTS) are experienced in an increasing number of TBI individuals that also display resistance to traditional anti-seizure medications (ASMs). Sonic hedgehog (Shh) is a signaling pathway that is upregulated following central nervous system damage in zebrafish and aids injury-induced regeneration. Using a modified Marmarou weight drop on adult zebrafish, we examined PTS following TBI and Shh modulation. We found that inhibiting Shh signaling by cyclopamine significantly increased PTS in TBI fish, prolonged the timeframe PTS was observed, and decreased survival across all TBI severities. Shh-inhibited TBI fish failed to respond to traditional ASMs, but were attenuated when treated with CNQX, which blocks ionotropic glutamate receptors. We found that the Smoothened agonist, purmorphamine, increased Eaat2a expression in undamaged brains compared to untreated controls, and purmorphamine treatment reduced glutamate excitotoxicity following TBI. Similarly, purmorphamine reduced PTS, edema, and cognitive deficits in TBI fish, while these pathologies were increased and/or prolonged in cyclopamine-treated TBI fish. However, the increased severity of TBI phenotypes with cyclopamine was reduced by cotreating fish with ceftriaxone, which induces Eaat2a expression. Collectively, these data suggest that Shh signaling induces Eaat2a expression and plays a role in regulating TBI-induced glutamate excitotoxicity and TBI sequelae.

Neuroprotective efficacy of 4-Hydroxyisoleucine in experimentally induced intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a severe form of brain injury, which is a major cause of mortality in humans. Hydrocephalus and cerebral hematoma lead to severe neurological deficits. A single autologous blood (ALB) injection in rats' brains induces hemorrhage and other conditions that regularly interfere with the standard treatment of several cellular and molecular pathways. Several studies have found that IGF-1/GLP-1 decreases the production of inflammatory markers in peripheral tissues, while some have found that they also have pro-inflammatory functions. Since these receptors are down-regulated in hemorrhagic situations, we looked into the potential neuroprotective effect of 4-hydroxyisoleucine (4-HI); 50 mg/kg and 100 mg/kg, an active compound Trigonellafoenum-graecum, on post-hemorrhagic deficits in rats. Long-term oral administration of 4-HI for 35 days has improved behavioral and neurochemical deficits and severe pathological changes and improved cellular and molecular markers, apoptotic markers in the ALB-induced ICH experimental model.

Furthermore, the findings revealed that 4-HI also improved the levels of other neurotransmitters (Ach, DOPA, GABA, glutamate); inflammatory cytokines (TNF-alpha, IL-1β, IL-17), and oxidative stress markers (MDA, nitrite, LDH, AchE, SOD, CAT, GPx, GSH) in the brain when evaluated after Day 35. There is no proven treatment available for the prevention of post-brain hemorrhage and neurochemical malfunction; available therapy is only for symptomatic relief of the patient. Thus, 4-HI could be a potential clinical approach for treating post-brain haemorrhage and neurochemical changes caused by neurological damage. Furthermore, 4-HI may be linked to other standard therapeutic therapies utilized in ICH as a potential pharmacological intervention.

Nrf2/HO-1 Signaling Activator Acetyl-11-keto-beta Boswellic Acid (AKBA)-Mediated Neuroprotection in Methyl Mercury-Induced Experimental Model of ALS

Methylmercury (MeHg) is a potent neurotoxin that causes neurotoxicity and neuronal cell death. MeHg exposure also leads to oligodendrocyte destruction, glial cell overactivation, and demyelination of motor neurons in the motor cortex and spinal cord. As a result, MeHg plays an important role in the progression of amyotrophic lateral sclerosis (ALS)-like neurocomplications. ALS is a fatal neurodegenerative disorder in which neuroinflammation is the leading cause of further CNS demyelination. Nuclear factor erythroid-2-related factor-2 (Nrf2)/Heme oxygenase-1 (HO-1) signaling pathway was thought to be a potential target for neuroprotection in ALS. Acetyl-11-keto-beta-boswellic acid (AKBA) is a multi-component pentacyclic triterpenoid mixture derived from Boswellia serrata with anti-inflammatory and antioxidant properties. The research aimed to investigate whether AKBA, as a Nrf2 / HO-1 activator, can provide protection against ALS. Thus, we explored the role of AKBA on the Nrf2/HO-1 signaling pathway in a MeHg-induced experimental ALS model. In this study, ALS was induced in Wistar rats by oral gavage of MeHg 5 mg/kg for 21 days. An open field test, force swim test, and grip strength were performed to observe experimental rats' motor coordination behaviors. In contrast, a morris water maze was performed for learning and memory. Administration of AKBA 50 mg/kg and AKBA 100 mg/kg continued from day 22 to 42. Neurochemical parameters were evaluated in the rat's brain homogenate. In the meantime, post-treatment with AKBA significantly improved behavioral, neurochemical, and gross pathological characteristics in the brain of rats by increasing the amount of Nrf2/HO-1 in brain tissue. Collectively, our findings indicated that AKBA could potentially avoid demyelination and encourage remyelination.

Targeting PI3K-AKT/mTOR signaling in the prevention of autism

PI3K-AKT/mTOR signaling pathway represents an essential signaling mechanism for mammalian enzyme-related receptors in transducing signals or biological processes such as cell development, differentiation, cell survival, protein synthesis, and metabolism. Upregulation of the PI3K-AKT/mTOR signaling pathway involves many human brain abnormalities, including autism and other neurological dysfunctions. Autism is a neurodevelopmental disorder associated with behavior and psychiatric illness. This research-based review discusses the functional relationship between the neuropathogenic factors associated with PI3K-AKT/mTOR signaling pathway. Ultimately causes autism-like conditions associated with genetic alterations, neuronal apoptosis, mitochondrial dysfunction, and neuroinflammation. Therefore, inhibition of the PI3K-AKT/mTOR signaling pathway may have an effective therapeutic value for autism treatment. The current review also summarizes the involvement of PI3K-AKT/mTOR signaling pathway inhibitors in the treatment of autism and other neurodegenerative disorders.