ABSTRACT
BACKGROUND AND AIMS: Sodium-glucose cotransporter 2 inhibitors (SGLT2is) can ameliorate arrhythmias; however, the mechanisms underlying their antiarrhythmic effect remain unclear. Therefore, we aimed to test the hypothesis that the SGLT2i empagliflozin (EMPA) ameliorates ventricular arrhythmias caused by myocardial infarction (MI) by inhibiting sympathetic remodeling. METHODS: Male nondiabetic Sprague-Dawley rats were divided into Sham ( n â=â10), MI ( n â=â13), low-EMPA (10âmg/kg/day; n â=â13), and high-EMPA (30âmg/kg/day; n â=â13) groups. Except for the Sham group, MI models were established by ligation of the left anterior descending coronary artery. After 4 weeks, the hearts were removed. Echocardiography, electrical stimulation, hematoxylin-eosin staining and Masson's staining, Western blotting, immunohistochemistry (IHC), and ELISA were performed. RESULTS: Except for left ventricular posterior wall thickness (LVPWT), EMPA treatment significantly ameliorated the left ventricular anterior wall thickness (LVAWT), interventricular septum thickness (IVST), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), and left ventricular ejection fraction (LVEF) in MI rats; there was no statistical difference between the low-EMPA and high-EMPA groups. The threshold for ventricular fibrillation induction and myocardial fibrosis was significantly ameliorated in EMPA-treated rats, and there was no statistical difference between the high-EMPA and low-EMPA groups. EMPA decreased the expression of nerve growth factor (NGF), tyrosine kinase receptor A (TrkA), tyrosine hydroxylase, and growth-associated protein 43 (GAP43) in the left ventricular infarction margin myocardium of MI rats, especially in the high-EMPA group, with a statistically significant difference between the high-EMPA and low-EMPA groups. High-EMPA significantly decreased noradrenaline (NE) levels in the blood of MI rats; however, there was no statistical difference between the low-EMPA and MI groups. CONCLUSION: EMPA ameliorated the occurrence of ventricular arrhythmias in MI rats, which may be related to a reduction in sympathetic activity, inhibition of the NGF/TrkA pathway, inhibition of sympathetic remodeling, and improvement in cardiac function and cardiac structural remodeling.
Subject(s)
Benzhydryl Compounds , Disease Models, Animal , Glucosides , Myocardial Infarction , Nerve Growth Factor , Rats, Sprague-Dawley , Signal Transduction , Sodium-Glucose Transporter 2 Inhibitors , Sympathetic Nervous System , Ventricular Remodeling , Animals , Male , Benzhydryl Compounds/pharmacology , Glucosides/pharmacology , Nerve Growth Factor/metabolism , Myocardial Infarction/physiopathology , Myocardial Infarction/drug therapy , Myocardial Infarction/complications , Myocardial Infarction/pathology , Myocardial Infarction/metabolism , Sympathetic Nervous System/drug effects , Sympathetic Nervous System/physiopathology , Sodium-Glucose Transporter 2 Inhibitors/pharmacology , Ventricular Remodeling/drug effects , Signal Transduction/drug effects , Receptor, trkA/metabolism , Receptor, trkA/antagonists & inhibitors , GAP-43 Protein/metabolism , Ventricular Function, Left/drug effects , Arrhythmias, Cardiac/etiology , Arrhythmias, Cardiac/prevention & control , Arrhythmias, Cardiac/physiopathology , Arrhythmias, Cardiac/drug therapy , Rats , Anti-Arrhythmia Agents/pharmacology , Connexin 43ABSTRACT
Schizophrenia is associated with altered cortical circuitry. Although the schizophrenia risk gene NRG1 is known to affect the wiring of inhibitory interneurons, its role in excitatory neurons and axonal development is unclear. Here, we investigated the role of Nrg1 in the development of the corpus callosum, the major interhemispheric connection formed by cortical excitatory neurons. We found that deletion of Nrg1 impaired callosal axon development in vivo. Experiments in vitro and in vivo demonstrated that Nrg1 is cell-autonomously required for axonal outgrowth and that intracellular signaling of Nrg1 is sufficient to promote axonal development in cortical neurons and specifically in callosal axons. Furthermore, our data suggest that Nrg1 signaling regulates the expression of Growth Associated Protein 43, a key regulator of axonal growth. In conclusion, our study demonstrates that NRG1 is involved in the formation of interhemispheric callosal connections and provides a novel perspective on the relevance of NRG1 in excitatory neurons and in the etiology of schizophrenia.
Subject(s)
Axons , Corpus Callosum , Neuregulin-1 , Signal Transduction , Animals , Neuregulin-1/metabolism , Neuregulin-1/genetics , Corpus Callosum/metabolism , Axons/metabolism , Mice , Schizophrenia/metabolism , Schizophrenia/genetics , Schizophrenia/etiology , Schizophrenia/pathology , Mice, Knockout , Neurons/metabolism , GAP-43 Protein/metabolism , GAP-43 Protein/genetics , Mice, Inbred C57BLABSTRACT
Plants are a valuable source of information for pharmacological research and new drug discovery. The present study aimed to evaluate the neuroprotective potential of the leaves of the medicinal plant Sterculia setigera. In vitro, the effect of Sterculia setigera leaves dry hydroethanolic extract (SSE) was tested on cultured cerebellar granule neurons (CGN) survival when exposed to hydrogen peroxide (H2O2) or 6-hydroxydopamine (6-OHDA), using the viability probe fluorescein diacetate (FDA), a lactate dehydrogenase (LDH) activity assay, an immunocytochemical staining against Gap 43, and the quantification of the expression of genes involved in apoptosis, necrosis, or oxidative stress. In vivo, the effect of intraperitoneal (ip) injection of SSE was assessed on the developing brain of 8-day-old Wistar rats exposed to ethanol neurotoxicity by measuring caspase-3 activity on cerebellum homogenates, the expression of some genes in tissue extracts, the thickness of cerebellar cortical layers and motor coordination. In vitro, SSE protected CGN against H2O2 and 6-OHDA-induced cell death at a dose of 10 µg/mL, inhibited the expression of genes Casp3 and Bad, and upregulated the expression of Cat and Gpx7. In vivo, SSE significantly blocked the deleterious effect of ethanol by reducing the activity of caspase-3, inhibiting the expression of Bax and Tp53, preventing the reduction of the thickness of the internal granule cell layer of the cerebellar cortex, and restoring motor functions. Sterculia setigera exerts neuroactive functions as claimed by traditional medicine and should be a good candidate for the development of a neuroprotective treatment against neurodegenerative diseases.
Subject(s)
Cell Death , Ethanol , Neurons , Neuroprotective Agents , Plant Extracts , Plant Leaves , Sterculia , Animals , Rats , Caspase 3/metabolism , Ethanol/administration & dosage , Ethanol/chemistry , Ethanol/toxicity , Hydrogen Peroxide/toxicity , Neuroprotective Agents/administration & dosage , Neuroprotective Agents/chemistry , Neuroprotective Agents/pharmacology , Oxidopamine/toxicity , Rats, Wistar , Sterculia/chemistry , Plant Leaves/chemistry , Plants, Medicinal/chemistry , Neurons/cytology , Neurons/drug effects , Neurons/enzymology , Neurons/pathology , Lactate Dehydrogenases/metabolism , GAP-43 Protein/analysis , Apoptosis/genetics , Oxidative Stress/genetics , Cerebellum/cytology , Cerebellum/drug effects , Cerebellum/pathology , Cerebellum/physiology , Male , Female , Cells, Cultured , Cell Death/drug effects , Gene Expression Regulation/drug effects , Phytochemicals/administration & dosage , Phytochemicals/analysis , Phytochemicals/chemistry , Phytochemicals/pharmacology , Plant Extracts/administration & dosage , Plant Extracts/chemistry , Plant Extracts/pharmacology , Antioxidants/analysis , Antioxidants/chemistry , Antioxidants/pharmacology , Spectrometry, Mass, Electrospray Ionization , Tandem Mass Spectrometry , Liquid Chromatography-Mass Spectrometry , Secondary MetabolismABSTRACT
Growth-associated protein 43 (GAP-43) is found in the axonal terminal of neurons in the limbic system, which is affected in people with Alzheimer's disease (AD). We assumed GAP-43 may contribute to AD progression and serve as a biomarker. So, in a two-year follow-up study, we assessed GAP-43 changes and whether they are correlated with tensor-based morphometry (TBM) findings in patients with mild cognitive impairment (MCI). We included MCI and cognitively normal (CN) people with available baseline and follow-up cerebrospinal fluid (CSF) GAP-43 and TBM findings from the ADNI database. We assessed the difference between the two groups and correlations in each group at each time point. CSF GAP-43 and TBM measures were similar in the two study groups in all time points, except for the accelerated anatomical region of interest (ROI) of CN subjects that were significantly greater than those of MCI. The only significant correlations with GAP-43 observed were those inverse correlations with accelerated and non-accelerated anatomical ROI in MCI subjects at baseline. Plus, all TBM metrics decreased significantly in all study groups during the follow-up in contrast to CSF GAP-43 levels. Our study revealed significant associations between CSF GAP-43 levels and TBM indices among people of the AD spectrum.
Subject(s)
Biomarkers , Cognitive Dysfunction , GAP-43 Protein , Aged , Aged, 80 and over , Female , Humans , Male , Alzheimer Disease/pathology , Alzheimer Disease/cerebrospinal fluid , Alzheimer Disease/diagnostic imaging , Biomarkers/cerebrospinal fluid , Brain/pathology , Brain/diagnostic imaging , Cognitive Dysfunction/cerebrospinal fluid , Cognitive Dysfunction/pathology , Cognitive Dysfunction/diagnostic imaging , Diffusion Tensor Imaging/methods , Disease Progression , Follow-Up Studies , GAP-43 Protein/cerebrospinal fluidABSTRACT
AIMS: Alzheimer's disease (AD), the most common neurodegenerative disorder associated with aging, is characterized by amyloid-ß (Aß) plaques in the hippocampus. Ergosterol, a mushroom sterol, exhibits neuroprotective activities; however, the underlying mechanisms of ergosterol in promoting neurite outgrowth and preventing Aß-associated aging have never been investigated. We aim to determine the beneficial activities of ergosterol in neuronal cells and Caenorhabditis elegans (C. elegans). MATERIALS AND METHODS: The neuritogenesis and molecular mechanisms of ergosterol were investigated in wild-type and Aß precursor protein (APP)-overexpressing Neuro2a cells. The anti-amyloidosis properties of ergosterol were determined by evaluating in vitro Aß production and the potential inhibition of Aß-producing enzymes. Additionally, AD-associated transgenic C. elegans was utilized to investigate the in vivo attenuating effects of ergosterol. KEY FINDINGS: Ergosterol promoted neurite outgrowth in Neuro2a cells through the upregulation of the transmembrane protein Teneurin-4 (Ten-4) mRNA and protein expressions, phosphorylation of the extracellular signal-regulated kinases (ERKs), activity of cAMP response element (CRE), and growth-associated protein-43 (GAP-43). Furthermore, ergosterol enhanced neurite outgrowth in transgenic Neuro2A cells overexpressing either the wild-type APP (Neuro2a-APPwt) or the Swedish mutant APP (Neuro2a-APPswe) through the Ten-4/ERK/CREB/GAP-43 signaling pathway. Interestingly, ergosterol inhibited Aß synthesis in Neuro2a-APPwt cells. In silico analysis indicated that ergosterol can interact with the catalytic sites of ß- and γ-secretases. In Aß-overexpressing C. elegans, ergosterol decreased Aß accumulation, increased chemotaxis behavior, and prolonged lifespan. SIGNIFICANCE: Ergosterol is a potential candidate compound that might benefit AD patients by promoting neurite outgrowth, inhibiting Aß synthesis, and enhancing longevity.
Subject(s)
Alzheimer Disease , Animals , Humans , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/metabolism , Amyloid Precursor Protein Secretases/metabolism , Animals, Genetically Modified/metabolism , Caenorhabditis elegans/metabolism , Extracellular Signal-Regulated MAP Kinases/metabolism , GAP-43 Protein , Longevity , Neuroblastoma , Neuronal Outgrowth , Cell Line, TumorABSTRACT
BACKGROUND: Postherpetic pain (PHP) is difficult to control. Although Neurotropin® (NTP) and methylcobalamin (MCB) are often prescribed to treat the pain, the efficacy of combined treatment for PHP remains imcompletely understood. OBJECTIVE: In this study, we investigate the combined effects of NTP and MCB on PHP in mice. METHODS: NTP and MCB were administered from day 10-29 after herpes simplex virus type-1 (HSV-1) infection. The pain-related responses were evaluated using a paint brush. The expression of neuropathy-related factor (ATF3) and nerve repair factors (GAP-43 and SPRR1A) in the dorsal root ganglion (DRG) and neurons in the skin were evaluated by immunohistochemical staining. Nerve growth factor (NGF) and neurotrophin-3 (NT3) mRNA expression levels were evaluated using real-time PCR. RESULTS: Repeated treatment with NTP and MCB after the acute phase inhibited PHP. Combined treatment with these drugs inhibited PHP at an earlier stage than either treatment alone. In the DRG of HSV-1-infected mice, MCB, but not NTP, decreased the number of cells expressing ATF3 and increased the number of cells expressing GAP-43- and SPRR1A. In addition, MCB, but not NTP, also increased and recovered non-myelinated neurons decreased in the lesional skin. NTP increased the mRNA levels of NTF3 in keratinocytes, while MCB increased that of NGF in Schwann cells. CONCLUSION: These results suggest that combined treatment with NTP and MCB is useful for the treatment of PHP. The combined effect may be attributed to the different analgesic mechanisms of these drugs.
Subject(s)
Herpes Simplex , Herpesvirus 1, Human , Neuralgia, Postherpetic , Polysaccharides , Vitamin B 12/analogs & derivatives , Mice , Animals , Neuralgia, Postherpetic/drug therapy , Nerve Growth Factor/metabolism , GAP-43 Protein/pharmacology , Herpes Simplex/complications , Herpes Simplex/drug therapy , RNA, MessengerABSTRACT
Ischemic stroke is a common intravascular disease and one of the leading causes of death and disability. The salidroside derivative SHPL-49, which we previously synthesized, significantly attenuates cerebral ischemic injury in a rat model of permanent middle cerebral artery occlusion. To explore the neuroprotective mechanism of SHPL-49, the effects of SHPL-49 on the expression levels of neurotrophic factors in neurons and microglia and the polarization of microglia were investigated in the present study. SHPL-49 activated the brain-derived neurotrophic factor (BDNF) pathway, decreased the number of degenerated neurons, and accelerated neurogenesis in rats with cerebral ischemia. In addition, SHPL-49 promoted the polarization of microglia toward the M2 phenotype to alleviate neuroinflammation. In BV2 cells, SHPL-49 upregulated CD206 mRNA and protein levels and inhibited CD86 mRNA and protein levels. SHPL-49 also increased neurotrophic factor secretion in BV2 cells, which indirectly promoted the survival of primary neurons after oxygen-glucose deprivation (OGD). Proteomics analysis revealed that SHPL-49 promoted growth-associated protein 43 (Gap43) expression. SHPL-49 enhanced synaptic plasticity and increased Gap43 protein levels via activation of the BDNF pathway in the OGD primary neuron model. These results indicate that SHPL-49 prevents cerebral ischemic injury by activating neurotrophic factor pathways and altering microglial polarization. Thus, SHPL-49 is a potential neuroprotective agent.
Subject(s)
Brain Ischemia , Brain-Derived Neurotrophic Factor , GAP-43 Protein , Glucosides , Microglia , Neurons , Neuroprotective Agents , Phenols , Rats, Sprague-Dawley , Receptor, trkB , Signal Transduction , Animals , Brain-Derived Neurotrophic Factor/metabolism , Neuroprotective Agents/pharmacology , Glucosides/pharmacology , Phenols/pharmacology , Male , Rats , GAP-43 Protein/metabolism , Microglia/drug effects , Microglia/metabolism , Brain Ischemia/drug therapy , Brain Ischemia/metabolism , Signal Transduction/drug effects , Neurons/drug effects , Neurons/metabolism , Neurons/pathology , Receptor, trkB/metabolism , Infarction, Middle Cerebral Artery/drug therapy , Infarction, Middle Cerebral Artery/pathology , Infarction, Middle Cerebral Artery/metabolism , Cell Line , Disease Models, Animal , Neurogenesis/drug effects , MiceABSTRACT
Age-related reduction in spine density, synaptic marker expression, and synaptic efficiency are frequently reported. These changes provide the cellular and molecular basis for the cognitive decline characteristic for old age. Nevertheless, there are several approaches that have the potential to ameliorate these processes and improve cognition, caloric restriction being one of the most promising and widely studied. While lifelong caloric restriction is known for its numerous beneficial effects, including improved cognitive abilities and increased expression of proteins essential for synaptic structure and function, the effects of late-onset and/or short-term CR on synaptic plasticity have yet to be investigated. We have previously documented that the effects of CR are strongly dependent on whether CR is initiated in young or old subjects. With this in mind, we conducted a long-term study in aging Wistar rats to examine changes in the expression of several key synaptic markers under the regimen of CR started at different time points in life. We found a significant increase in the expression of both presynaptic and postsynaptic markers. However, taking into account previously reported changes in the behavior detected in these animals, we consider that this increase cannot represent beneficial effect of CR.
Subject(s)
Caloric Restriction , Neuronal Plasticity , Animals , Male , Rats , Age Factors , alpha-Synuclein/genetics , alpha-Synuclein/metabolism , Cadherins/genetics , Cadherins/metabolism , Diet , Disks Large Homolog 4 Protein/genetics , Disks Large Homolog 4 Protein/metabolism , GAP-43 Protein/genetics , GAP-43 Protein/metabolism , Gene Expression Regulation/physiology , Neuronal Plasticity/physiology , Rats, Wistar , RNA, Messenger/genetics , RNA, Messenger/metabolism , Synaptophysin/genetics , Synaptophysin/metabolismABSTRACT
Background: Cerebral microbleeds (CMB) play an important role in neurodegenerative pathology. Objective: The present study aims to test whether cerebrospinal fluid (CSF) growth-associated protein 43 (GAP-43) level is linked to CMBs in elderly people. Methods: A total of 750 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) who had measurements of GAP-43 and CMBs were included in the study. According to the presence and extent of CMBs, participants were stratified into different groups. Regression analyses were used to assess cross-sectional and longitudinal associations between GAP-43 and CMBs. Results: Participants with CMB were slightly older and had higher concentrations of CSF GAP43. In multivariable adjusted analyses for age, gender, APOEÉ4 status, and cognitive diagnoses, higher CSF GAP-43 concentrations were modestly associated with CMB presence (ORâ=â1.169, 95% CIâ=â1.001-1.365) and number (ß=â0.020, SEâ=â0.009, pâ=â0.027). Similarly, higher CSF GAP43 concentrations were accrual of CMB lesions, associated with higher CMB progression (ORâ=â1.231, 95% CIâ=â1.044-1.448) and number (ß=â0.017, SEâ=â0.005, pâ=â0.001) in the follow up scan. In stratified analyses, slightly stronger associations were noted in male participants, those 65 years and older, carriers of APOEÉ4 alleles, and with more advanced cognitive disorders. Conclusions: CSF GAP-43 was cross-sectionally associated with the presence and extent of CMBs. GAP-43 might be used as a biomarker to track the dynamic changes of CMBs in elderly persons.
Subject(s)
Cerebral Hemorrhage , Magnetic Resonance Imaging , Humans , Male , Aged , GAP-43 Protein , Cerebral Hemorrhage/cerebrospinal fluid , Longitudinal Studies , Cross-Sectional Studies , Magnetic Resonance Imaging/methodsABSTRACT
A novel curcumin formulation increases relative absorption by 46 times (CurcuWIN®) of the total curcuminoids over the unformulated standard curcumin form. However, the exact mechanisms by which curcumin demonstrates its neuroprotective effects are not fully understood. This study aimed to investigate the impact of a novel formulation of curcumin on the expression of brain-derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP), a main component of the glial scar and growth-associated protein-43 (GAP-43), a signaling molecule in traumatic brain injury (TBI). Mice (adult, male, C57BL/6j) were randomly divided into three groups as follows: TBI group (TBI-induced mice); TBI + CUR group (TBI mice were injected i.p. curcumin just after TBI); TBI+ CurcuWIN® group (TBI mice were injected i.p. CurcuWIN® just after TBI). Brain injury was induced using a cold injury model. Injured brain tissue was stained with Cresyl violet to evaluate infarct volume and brain swelling, analyzed, and measured using ImageJ by Bethesda (MD, USA). Western blot analysis was performed to determine the protein levels related to injury. While standard curcumin significantly reduced brain injury, CurcuWIN® showed an even greater reduction associated with reductions in glial activation, NF-κB, and the inflammatory cytokines IL-1ß and IL-6. Additionally, both standard curcumin and CurcuWIN® led to increased BDNF, GAP-43, ICAM-1, and Nrf2 expression. Notably, CurcuWIN® enhanced their expression more than standard curcumin. This data suggests that highly bioavailable curcumin formulation has a beneficial effect on the traumatic brain in mice.
Subject(s)
Brain Injuries, Traumatic , Brain Injuries , Curcumin , Mice , Male , Animals , Cytokines/metabolism , Curcumin/pharmacology , Curcumin/therapeutic use , Brain-Derived Neurotrophic Factor , GAP-43 Protein , Mice, Inbred C57BL , Brain Injuries, Traumatic/drug therapy , Brain Injuries, Traumatic/complications , Brain Injuries, Traumatic/metabolism , Brain Injuries/complications , Inflammation , Disease Models, AnimalABSTRACT
In Alzheimer's disease, amyloid-beta (Aß) triggers the trans-synaptic spread of tau pathology, and aberrant synaptic activity has been shown to promote tau spreading. Aß induces aberrant synaptic activity, manifesting in increases in the presynaptic growth-associated protein 43 (GAP-43), which is closely involved in synaptic activity and plasticity. We therefore tested whether Aß-related GAP-43 increases, as a marker of synaptic changes, drive tau spreading in 93 patients across the aging and Alzheimer's spectrum with available CSF GAP-43, amyloid-PET and longitudinal tau-PET assessments. We found that (1) higher GAP-43 was associated with faster Aß-related tau accumulation, specifically in brain regions connected closest to subject-specific tau epicenters and (2) that higher GAP-43 strengthened the association between Aß and connectivity-associated tau spread. This suggests that GAP-43-related synaptic changes are linked to faster Aß-related tau spread across connected regions and that synapses could be key targets for preventing tau spreading in Alzheimer's disease.
Subject(s)
Alzheimer Disease , Cognitive Dysfunction , Humans , Alzheimer Disease/metabolism , GAP-43 Protein/genetics , GAP-43 Protein/metabolism , tau Proteins/metabolism , Amyloid beta-Peptides/metabolism , Brain/metabolism , Positron-Emission Tomography , Cognitive Dysfunction/metabolism , Biomarkers/metabolismABSTRACT
OBJECTIVES: In this study, we employed an in vitro culturing technique to investigate the impact of p53 on the modulation of growth-associated protein-43 (GAP-43) within the primary cortical neurons of rat specimens. METHODS: (1) Within the first 24 hours after birth, the bilateral cortex was extracted from newborn Wistar rats and primary cortical neurons were cultured and identified. (2) The changes in the mRNA and protein expressions of GAP-43 induced by p53 in rat primary cortical neurons cultured in vitro were identified utilizing real-time polymerase chain reaction and western blot techniques. RESULTS: (1) Lentiviral transfection of p53 within primary cortical neurons of rats elicited elevated levels of both mRNA and protein expressions of GAP-43, consequently culminating in a noteworthy augmentation of p53 expression. (2) The introduction of a p53 inhibitor in rat primary cortical neurons resulted in a reduction in both mRNA and protein expressions of GAP-43. CONCLUSION: Within primary rat cortical neurons, p53 has the potential to prompt an augmentation in both the transcriptional and protein expression levels of the GAP-43 protein.
Subject(s)
Cerebral Cortex , GAP-43 Protein , Neurons , Rats, Wistar , Tumor Suppressor Protein p53 , Up-Regulation , Animals , Rats , Cells, Cultured , Cerebral Cortex/metabolism , Cerebral Cortex/cytology , GAP-43 Protein/metabolism , GAP-43 Protein/genetics , Neurons/metabolism , Neurons/cytology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Tumor Suppressor Protein p53/metabolism , Tumor Suppressor Protein p53/geneticsABSTRACT
INTRODUCTION: Self-repair of spinal cord injury (SCI) has been found in humans and experimental animals with partial recovery of neurological functions. However, the regulatory mechanisms underlying the spontaneous locomotion recovery after SCI are elusive. AIMS: This study was aimed at evaluating the pathological changes in injured spinal cord and exploring the possible mechanism related to the spontaneous recovery. RESULTS: Immunofluorescence staining was performed to detect GAP43 expression in lesion site after spinal cord transection (SCT) in rats. Then RNA sequencing and gene ontology (GO) analysis were employed to predict lncRNA that correlates with GAP43. LncRNA smart-silencing was applied to verify the function of lncRNA vof16 in vitro, and knockout rats were used to evaluate its role in neurobehavioral functions after SCT. MicroRNA sequencing, target scan, and RNA22 prediction were performed to further explore the underlying regulatory mechanisms, and miR-185-5p stands out. A miR-185-5p site-regulated relationship with GAP43 and vof16 was determined by luciferase activity analysis. GAP43-silencing, miR-185-5p-mimic/inhibitor, and miR-185-5p knockout rats were also applied to elucidate their effects on spinal cord neurite growth and neurobehavioral function after SCT. We found that a time-dependent increase of GAP43 corresponded with the limited neurological recovery in rats with SCT. CRNA chip and GO analysis revealed lncRNA vof16 was the most functional in targeting GAP43 in SCT rats. Additionally, silencing vof16 suppressed neurite growth and attenuated the motor dysfunction in SCT rats. Luciferase reporter assay showed that miR-185-5p competitively bound the same regulatory region of vof16 and GAP43. CONCLUSIONS: Our data indicated miR-185-5p could be a detrimental factor in SCT, and vof16 may function as a ceRNA by competitively binding miR-185-5p to modulate GAP43 in the process of self-recovery after SCT. Our study revealed a novel vof16-miR-185-5p-GAP43 regulatory network in neurological self-repair after SCT and may underlie the potential treatment target for SCI.
Subject(s)
MicroRNAs , RNA, Long Noncoding , Spinal Cord Injuries , Animals , Rats , Luciferases/metabolism , MicroRNAs/genetics , MicroRNAs/metabolism , RNA, Long Noncoding/metabolism , Spinal Cord/metabolism , Spinal Cord Injuries/pathology , GAP-43 Protein/genetics , GAP-43 Protein/metabolismABSTRACT
Facial nerve regeneration still lacks a well-defined and practical clinical intervention. The survival of central facial motoneuron is a critical component in the successful peripheral facial nerve regeneration. Endogenous GDNF is vital for facial nerve regeneration according to earlier investigations. Nevertheless, the low endogenous GDNF level makes it challenging to achieve therapeutic benefits. Thus, we crushed the main trunk of facial nerve in SD rats to provide a model of peripheral facial paralysis, and we administered exogenous GDNF and Rapa treatments. We observed changes in the animal behavior scores, the morphology of facial nerve and buccinator muscle, the electrophysiological of facial nerve, and the expression of GDNF, GAP-43, and PI3K/AKT/mTOR signaling pathway-related molecules in the facial motoneurons. We discovered that GDNF could boost axon regeneration, hasten the recovery of facial paralysis symptoms and nerve conduction function, and increase the expression of GDNF, GAP-43, and PI3K/AKT/mTOR signaling pathway-related molecules in the central facial motoneurons. Therefore, exogenous GDNF injection into the buccinator muscle can enhance facial nerve regeneration following crushing injury and protect facial neurons via the PI3K/AKT/mTOR signaling pathway. This will offer a fresh perspective and theoretical foundation for the management of clinical facial nerve regeneration.
Subject(s)
Axons , Facial Nerve , Rats , Animals , Rats, Sprague-Dawley , Glial Cell Line-Derived Neurotrophic Factor/pharmacology , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-akt , GAP-43 Protein , Nerve Regeneration/physiology , Motor Neurons/physiology , TOR Serine-Threonine Kinases , Signal TransductionABSTRACT
Apolipoprotein E-ε4 (APOE-ε4) carriers had elevated cerebrospinal fluid (CSF) presynaptic protein growth-associated protein-43 (GAP-43), but the underlying mechanism is not fully understood. We investigated how the APOE-ε4 genotype affects the baseline and longitudinal changes in CSF GAP-43 and their associations with ß-amyloid positron emission tomography (Aß PET), CSF phosphorylated tau 181 (p-Tau181), neurodegeneration, and cognitive decline. Compared to APOE-ε4 non-carriers, APOE-ε4 carriers had higher baseline levels and faster rates of increases in Aß PET, CSF p-Tau181, and CSF GAP-43. Both higher baseline levels and faster rates of increase in CSF GAP-43 were associated with greater baseline Aß PET and CSF p-Tau181, which fully mediated the APOE-ε4 effect on CSF GAP-43 elevations. Independent of Aß PET and CSF p-Tau181, APOE-ε4 carriage was associated with exacerbated GAP-43-related longitudinal hippocampal atrophy and cognitive decline, especially in Aß+ participants (GAP-43 × time × APOE-ε4). These findings suggest that the APOE-ε4 effect on GAP-43-related presynaptic dysfunction is mediated by primary Alzheimer's pathologies and independently correlates to hippocampal atrophy and cognitive decline in the future.
Subject(s)
Alzheimer Disease , Apolipoprotein E4 , Cognitive Dysfunction , GAP-43 Protein , Humans , Alzheimer Disease/genetics , Amyloid beta-Peptides/cerebrospinal fluid , Apolipoprotein E4/genetics , Atrophy , Biomarkers/cerebrospinal fluid , Cognitive Dysfunction/pathology , GAP-43 Protein/cerebrospinal fluid , GAP-43 Protein/metabolism , tau Proteins/cerebrospinal fluidABSTRACT
Neuropathic pain is stubborn and associated with the peripheral nerve regeneration process. Nicotine has been found to reduce pain, but whether it is involved in the regulation of nerve regeneration and the underlying mechanism are unknown. In this study, we examined the mechanical allodynia thermal hyperalgesia together with the peripheral nerve regeneration after nicotine exposure in two rat neuropathic pain models. In the spinal nerve ligation model, in which anatomic nerve regeneration can be easily observed, nicotine reduced anatomic measures of regeneration as well as expression of regeneration marker growth-associated protein 43 (GAP43). In the tibial nerve crush model, nicotine treatment significantly suppressed GAP43 expression and functional reinnervation as measured by myelinated action potential and electromyography of gastrocnemius. In both models, nicotine treatment reduced macrophage density in the sensory ganglia and peripheral nerve. These effects of nicotine were reversed by the selective α7 nicotinic acetylcholine receptor (nAChR) blocker methyllycaconitine. In addition, nicotine significantly elevated expression of PTEN (the phosphatase and tensin homolog deleted on chromosome 10), a key player in both regeneration and pain. Pharmacological interference of PTEN could regulate GAP43 expression, pain-related behaviors, and macrophage infiltration in a nicotine-treated nerve crush model. Our results reveal that nicotine and its α7-nAChR regulate both peripheral nerve regeneration process and pain though PTEN and the downstream inflammation-related pathway.
Subject(s)
Neuralgia , Nicotine , Animals , Rats , Nicotine/pharmacology , Nerve Regeneration , Hyperalgesia/drug therapy , GAP-43 Protein , InflammationABSTRACT
Cerebral ischemia is one of the major problems threatening global health. Many of the cerebral ischemia survivors would suffer from the physical and cognitive disabilities for their whole lifetime. Cell based-therapies have been introduced as a therapeutic approach for alleviating ischemia-enforced limitations. Photothrombotic stroke model was applied on the left medial prefrontal cortex (mPFC) of adult male BALB/c mice. Then, pericytes isolated from brain microvessels of adult male BALB/c mice, microglia isolated from brain cortices of the neonatal male BALB/c mice, and M2 phenotype shifted microglia by IL-4 treatment were used for transplantation into the injured area after 24 h of ischemia induction. The behavioural outcomes evaluated by social interaction and Barnes tests and the levels of growth associated protein (GAP)-43 and inflammatory cytokine interleukin (IL)-1 protein were assessed by western blotting 7 days after cell transplantation. Animals in both of the microglia + pericytes and microglia M2 + pericytes transplanted groups showed better performance in social memory as well as enhanced spatial learning and memory compared to ischemic controls. Also, improved escape latency was only observed in microglia M2 + pericytes (p < 0.01) group compared to ischemic controls. GAP-43 showed significant protein expression in microglia + pericytes and microglia M2 + pericytes groups compared to the control group. Conversely, IL-1 levels diminished in all of the pericytes microglia + pericytes, and microglia M2 + pericytes groups compared to the ischemic controls. Current study highlights efficiency of M2 microglia and pericytes combinatory transplantation therapeutic role on relieving ischemic stroke outcomes.
Subject(s)
Brain Ischemia , Microglia , Mice , Animals , Male , Microglia/metabolism , Pericytes/metabolism , Brain Ischemia/metabolism , Prefrontal Cortex/metabolism , Cognition , GAP-43 Protein/metabolism , Ischemia/metabolismABSTRACT
This study investigated the possible beneficial role of the bee venom (BV, Apis mellifera L.) against zinc oxide nanoparticles (ZNPs)-induced neurobehavioral and neurotoxic impacts in rats. Fifty male Sprague Dawley rats were alienated into five groups. Three groups were intraperitoneally injected distilled water (C 28D group), ZNPs (100 mg/kg b.wt) (ZNPs group), or ZNPs (100 mg/kg.wt) and BV (1 mg/ kg.bwt) (ZNPs + BV group) for 28 days. One group was intraperitoneally injected with 1 mL of distilled water for 56 days (C 56D group). The last group was intraperitoneally injected with ZNPs for 28 days, then BV for another 28 days at the same earlier doses and duration (ZNPs/BV group). Depression, anxiety, locomotor activity, spatial learning, and memory were evaluated using the forced swimming test, elevated plus maze, open field test, and Morris water maze test, respectively. The brain contents of dopamine, serotonin, total antioxidant capacity (TAC), malondialdehyde (MDA), and Zn were estimated. The histopathological changes and immunoexpressions of neurofilament and GAP-43 protein in the brain tissues were followed. The results displayed that BV significantly decreased the ZNPs-induced depression, anxiety, memory impairment, and spatial learning disorders. Moreover, the ZNPs-induced increment in serotonin and dopamine levels and Zn content was significantly suppressed by BV. Besides, BV significantly restored the depleted TAC but minimized the augmented MDA brain content associated with ZNPs exposure. Likewise, the neurodegenerative changes induced by ZNPs were significantly abolished by BV. Also, the increased neurofilament and GAP-43 immunoexpression due to ZNPs exposure were alleviated with BV. Of note, BV achieved better results in the ZNPs + BV group than in the ZNPs/BV group. Conclusively, these results demonstrated that BV could be employed as a biologically effective therapy to mitigate the neurotoxic and neurobehavioral effects of ZNPs, particularly when used during ZNPs exposure.
Subject(s)
Bee Venoms , Nanoparticles , Neurotoxicity Syndromes , Zinc Oxide , Rats , Animals , Male , Bees , Rats, Sprague-Dawley , GAP-43 Protein/metabolism , GAP-43 Protein/pharmacology , Zinc Oxide/metabolism , Bee Venoms/pharmacology , Bee Venoms/toxicity , Dopamine/metabolism , Dopamine/pharmacology , Serotonin/metabolism , Intermediate Filaments/metabolism , Antioxidants/metabolism , Neurotoxicity Syndromes/metabolism , BrainABSTRACT
Objective.Spinal cord injury (SCI) leads to debilitating sensorimotor deficits that greatly limit quality of life. This work aims to develop a mechanistic understanding of how to best promote functional recovery following SCI. Electrical spinal stimulation is one promising approach that is effective in both animal models and humans with SCI. Optogenetic stimulation is an alternative method of stimulating the spinal cord that allows for cell-type-specific stimulation. The present work investigates the effects of preferentially stimulating neurons within the spinal cord and not glial cells, termed 'neuron-specific' optogenetic spinal stimulation. We examined forelimb recovery, axonal growth, and vasculature after optogenetic or sham stimulation in rats with cervical SCI.Approach.Adult female rats received a moderate cervical hemicontusion followed by the injection of a neuron-specific optogenetic viral vector ipsilateral and caudal to the lesion site. Animals then began rehabilitation on the skilled forelimb reaching task. At four weeks post-injury, rats received a micro-light emitting diode (µLED) implant to optogenetically stimulate the caudal spinal cord. Stimulation began at six weeks post-injury and occurred in conjunction with activities to promote use of the forelimbs. Following six weeks of stimulation, rats were perfused, and tissue stained for GAP-43, laminin, Nissl bodies and myelin. Location of viral transduction and transduced cell types were also assessed.Main Results.Our results demonstrate that neuron-specific optogenetic spinal stimulation significantly enhances recovery of skilled forelimb reaching. We also found significantly more GAP-43 and laminin labeling in the optogenetically stimulated groups indicating stimulation promotes axonal growth and angiogenesis.Significance.These findings indicate that optogenetic stimulation is a robust neuromodulator that could enable future therapies and investigations into the role of specific cell types, pathways, and neuronal populations in supporting recovery after SCI.
Subject(s)
Cervical Cord , Spinal Cord Injuries , Humans , Rats , Female , Animals , Optogenetics , GAP-43 Protein , Laminin , Quality of Life , Spinal Cord , Forelimb/pathology , Forelimb/physiology , Recovery of Function/physiologyABSTRACT
This study investigated the effect of Lianmei Qiwu Decoction(LMQWD) on the improvement of cardiac autonomic nerve remodeling in the diabetic rat model induced by the high-fat diet and explored the underlying mechanism of LMQWD through the AMP-activated protein kinase(AMPK)/tropomyosin receptor kinase A(TrkA)/transient receptor potential melastatin 7(TRPM7) signaling pathway. The diabetic rats were randomly divided into a model group, an LMQWD group, an AMPK agonist group, an unloaded TRPM7 adenovirus group(TRPM7-N), an overexpressed TRPM7 adenovirus group(TRPM7), an LMQWD + unloaded TRPM7 adenovirus group(LMQWD+TRPM7-N), an LMQWD + overexpressed TRPM7 adenovirus group(LMQWD+TRPM7), and a TRPM7 channel inhibitor group(TRPM7 inhibitor). After four weeks of treatment, programmed electrical stimulation(PES) was employed to detect the arrhythmia susceptibility of rats. The myocardial cell structure and myocardial tissue fibrosis of myocardial and ganglion samples in diabetic rats were observed by hematoxylin-eosin(HE) staining and Masson staining. The immunohistochemistry, immunofluorescence, real-time quantitative polymerase chain reaction(RT-PCR), and Western blot were adopted to detect the distribution and expression of TRPM7, tyrosine hydroxylase(TH), choline acetyltransferase(ChAT), growth associated protein-43(GAP-43), nerve growth factor(NGF), p-AMPK/AMPK, and other genes and related neural markers. The results showed that LMQWD could significantly reduce the arrhythmia susceptibility and the degree of fibrosis in myocardial tissues, decrease the levels of TH, ChAT, and GAP-43 in the myocardium and ganglion, increase NGF, inhibit the expression of TRPM7, and up-regulate p-AMPK/AMPK and p-TrkA/TrkA levels. This study indicated that LMQWD could attenuate cardiac autonomic nerve remodeling in the diabetic state, and its mechanism was associated with the activation of AMPK, further phosphorylation of TrkA, and inhibition of TRPM7 expression.