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Synaptic changes are early manifestations of neuronal dysfunction in Huntington's disease (HD). However, the mechanisms by which mutant HTT protein impacts synaptogenesis and function are not well understood. Herein we explored HD pathogenesis in the BACHD mouse model by examining synaptogenesis and function in long term primary cortical cultures. At DIV14 (days in vitro), BACHD cortical neurons showed no difference from WT neurons in synaptogenesis as revealed by colocalization of a pre-synaptic (Synapsin I) and a post-synaptic (PSD95) marker. From DIV21 to DIV35, BACHD neurons showed progressively reduced colocalization of Synapsin I and PSD95 relative to WT neurons. The deficits were effectively rescued by treatment of BACHD neurons with BDNF. The recombinant apical domain of CCT1 (ApiCCT1) yielded a partial rescuing effect. BACHD neurons also showed culture age-related significant functional deficits as revealed by multielectrode arrays (MEAs). These deficits were prevented by BDNF, whereas ApiCCT1 showed a less potent effect. These findings are evidence that deficits in BACHD synapse and function can be replicated in vitro and that BDNF or a TRiC-inspired reagent can potentially be protective against these changes in BACHD neurons. Our findings support the use of cellular models to further explicate HD pathogenesis and potential treatments.
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Fator Neurotrófico Derivado do Encéfalo , Córtex Cerebral , Modelos Animais de Doenças , Doença de Huntington , Neurônios , Sinapses , Animais , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Sinapses/metabolismo , Sinapses/efeitos dos fármacos , Sinapses/patologia , Córtex Cerebral/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Camundongos , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/patologia , Camundongos Transgênicos , Células Cultivadas , Sinapsinas/metabolismo , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Camundongos Endogâmicos C57BLRESUMO
Axonal degeneration is a key component of neurodegenerative diseases such as Huntington's disease (HD), Alzheimer's disease, and amyotrophic lateral sclerosis. Nicotinamide, an NAD+ precursor, has long since been implicated in axonal protection and reduction of degeneration. However, studies on nicotinamide (NAm) supplementation in humans indicate that NAm has no protective effect. Sterile alpha and toll/interleukin receptor motif-containing protein 1 (SARM1) regulates several cell responses to axonal damage and has been implicated in promoting neuronal degeneration. SARM1 inhibition seems to result in protection from neuronal degeneration while hydrogen peroxide has been implicated in oxidative stress and axonal degeneration. The effects of laser-induced axonal damage in wild-type and HD dorsal root ganglion cells treated with NAm, hydrogen peroxide (H2O2), and SARM1 inhibitor DSRM-3716 were investigated and the cell body width, axon width, axonal strength, and axon shrinkage post laser-induced injury were measured.
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Doença de Huntington , Peróxido de Hidrogênio , Animais , Camundongos , Humanos , Niacinamida , Camundongos Knockout , Neurônios/metabolismo , Proteínas do Citoesqueleto/metabolismo , Proteínas do Domínio Armadillo/genética , Proteínas do Domínio Armadillo/metabolismoRESUMO
Introduction: Axonal transport of pro nerve growth factor (proNGF) is impaired in aged basal forebrain cholinergic neurons (BFCNs), which is associated with their degeneration. ProNGF is neurotrophic in the presence of its receptor tropomyosin-related kinase A (TrkA) but induces apoptosis via the pan-neurotrophin receptor (p75NTR) when TrkA is absent. It is well established that TrkA is lost while p75NTR is maintained in aged BFCNs, but whether aging differentially affects transport of proNGF via each receptor is unknown. Nitrative stress increases during aging, but whether age-induced nitrative stress differentially affects proNGF transport via TrkA versus p75NTR has not yet been studied. Answering these questions is essential for developing an accurate understanding of the mechanisms contributing to age-induced loss of proNGF transport and BFCN degeneration. Methods: In this study, fluorescence microscopy was used to analyze axonal transport of quantum dot labeled proNGF in rat BFCNs in vitro. Receptor specific effects were studied with proNGF mutants that selectively bind to either TrkA (proNGF-KKE) or p75NTR (proNGF-Δ9-13). Signaling factor activity was quantified via immunostaining. Results: Young BFCNs transported proNGF-KKE but not proNGF-Δ9-13, and proNGF transport was not different in p75NTR knockout BFCNs compared to wildtype BFCNs. These results indicate that young BFCNs transport proNGF via TrkA. In vitro aging increased transport of proNGF-Δ9-13 but decreased transport of proNGF-KKE. Treatment with the nitric oxide synthase inhibitor L-NAME reduced retrograde transport of proNGF-Δ9-13 in aged BFCNs while increasing retrograde transport of proNGF-KKE but did not affect TrkA or p75NTR levels. ProNGF-Δ9-13 induced greater pro-apoptotic signaling and neurodegeneration and less pro-survival signaling relative to proNGF-KKE. Discussion: Together, these results indicate that age-induced nitrative stress decreases proNGF transport via TrkA while increasing proNGF transport via p75NTR. These transport deficits are associated with decreased survival signaling, increased apoptotic signaling, and neurodegeneration. Our findings elucidate the receptor specificity of age-and nitrative stress-induced proNGF transport deficits. These results may help to rescue the neurotrophic signaling of proNGF in aging to reduce age-induced loss of BFCN function and cognitive decline.
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Neurodegenerative disorders of aging are characterized by the progressive accumulation of proteins such as α-synuclein (α-syn) and amyloid beta (Aß). Misfolded and aggregated α-syn has been implicated in neurological disorders such as Parkinson's disease, and Dementia with Lewy Bodies, but less so in Alzheimer's Disease (AD), despite the fact that accumulation of α-syn has been confirmed in over 50% of postmortem brains neuropathologically diagnosed with AD. To date, no therapeutic strategy has effectively or consistently downregulated α-syn in AD. Here we tested the hypothesis that by using a systemically-delivered peptide (ApoB11) bound to a modified antisense oligonucleotide against α-syn (ASO-α-syn), we can downregulate α-syn expression in an AD mouse model and improve behavioral and neuropathologic phenotypes. Our results demonstrate that monthly systemic treatment with of ApoB11:ASO α-syn beginning at 6 months of age reduces expression of α-synuclein in the brains of 9-month-old AD mice. Downregulation of α-syn led to reduction in Aß plaque burden, prevented neuronal loss and astrogliosis. Furthermore, we found that AD mice treated with ApoB11:ASO α-syn had greatly improved hippocampal and spatial memory function in comparison to their control counterparts. Collectively, our data supports the reduction of α-syn through use of systemically-delivered ApoB11:ASO α-syn as a promising future disease-modifying therapeutic for AD.
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Doença de Alzheimer , Oligonucleotídeos Antissenso , Animais , Camundongos , Oligonucleotídeos Antissenso/farmacologia , alfa-Sinucleína/genética , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides , Apolipoproteínas B , Modelos Animais de DoençasRESUMO
BACKGROUND: Alzheimer's disease (AD) cases are often characterized by the pathological accumulation of α-synuclein (α-syn) in addition to amyloid-ß (Aß) and tau hallmarks. The role of α-syn has been extensively studied in synucleinopathy disorders, but less so in AD. Recent studies have shown that α-syn may also play a role in AD and its downregulation may be protective against the toxic effects of Aß accumulation. OBJECTIVE: We hypothesized that selectively knocking down α-syn via RNA interference improves the neuropathological and biochemical findings in AD mice. METHODS: Here we used amyloid precursor protein transgenic (APP-Tg) mice to model AD and explore pathologic and behavioral phenotypes with knockdown of α-syn using RNA interference. We selectively reduced α-syn levels by stereotaxic bilateral injection of either LV-shRNA α-syn or LV-shRNA-luc (control) into the hippocampus of AD mice. RESULTS: We found that downregulation of α-syn results in significant reduction in the number of Aß plaques. In addition, mice treated with LV-shRNA α-syn had amelioration of abnormal microglial activation (Iba1) and astrocytosis (GFAP) phenotypes in AD mice. CONCLUSION: Our data suggests a novel link between Aß and α-syn pathology as well as a new therapeutic angle for targeting AD.
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Doença de Alzheimer , Camundongos , Animais , Doença de Alzheimer/patologia , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo , Interferência de RNA , Precursor de Proteína beta-Amiloide/genética , Peptídeos beta-Amiloides/metabolismo , Camundongos Transgênicos , Hipocampo/patologia , Placa Amiloide/patologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteínas tau/metabolismo , Modelos Animais de DoençasRESUMO
Endolysosomal defects in neurons are central to the pathogenesis of prion and other neurodegenerative disorders. In prion disease, prion oligomers traffic through the multivesicular body (MVB) and are routed for degradation in lysosomes or for release in exosomes, yet how prions impact proteostatic pathways is unclear. We found that prion-affected human and mouse brain showed a marked reduction in Hrs and STAM1 (ESCRT-0), which route ubiquitinated membrane proteins from early endosomes into MVBs. To determine how the reduction in ESCRT-0 impacts prion conversion and cellular toxicity in vivo, we prion-challenged conditional knockout mice (male and female) having Hrs deleted from neurons, astrocytes, or microglia. The neuronal, but not astrocytic or microglial, Hrs-depleted mice showed a shortened survival and an acceleration in synaptic derangements, including an accumulation of ubiquitinated proteins, deregulation of phosphorylated AMPA and metabotropic glutamate receptors, and profoundly altered synaptic structure, all of which occurred later in the prion-infected control mice. Finally, we found that neuronal Hrs (nHrs) depletion increased surface levels of the cellular prion protein, PrPC, which may contribute to the rapidly advancing disease through neurotoxic signaling. Taken together, the reduced Hrs in the prion-affected brain hampers ubiquitinated protein clearance at the synapse, exacerbates postsynaptic glutamate receptor deregulation, and accelerates neurodegeneration.SIGNIFICANCE STATEMENT Prion diseases are rapidly progressive neurodegenerative disorders characterized by prion aggregate spread through the central nervous system. Early disease features include ubiquitinated protein accumulation and synapse loss. Here, we investigate how prion aggregates alter ubiquitinated protein clearance pathways (ESCRT) in mouse and human prion-infected brain, discovering a marked reduction in Hrs. Using a prion-infection mouse model with neuronal Hrs (nHrs) depleted, we show that low neuronal Hrs is detrimental and markedly shortens survival time while accelerating synaptic derangements, including ubiquitinated protein accumulation, indicating that Hrs loss exacerbates prion disease progression. Additionally, Hrs depletion increases the surface distribution of prion protein (PrPC), linked to aggregate-induced neurotoxic signaling, suggesting that Hrs loss in prion disease accelerates disease through enhancing PrPC-mediated neurotoxic signaling.
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Doenças Neurodegenerativas , Doenças Priônicas , Príons , Masculino , Feminino , Camundongos , Humanos , Animais , Príons/metabolismo , Proteínas Priônicas/metabolismo , Receptores de AMPA/metabolismo , Neurônios/metabolismo , Doenças Priônicas/metabolismo , Doenças Priônicas/patologia , Doenças Neurodegenerativas/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismoRESUMO
Brain-derived neurotrophic factor (BDNF) and its receptors tropomyosin kinase receptor B (TrkB) and the p75 neurotrophin receptor (p75) are the primary regulators of dendritic growth in the CNS. After being bound by BDNF, TrkB and p75 are endocytosed into endosomes and continue signaling within the cell soma, dendrites, and axons. We studied the functional role of BDNF axonal signaling in cortical neurons derived from different transgenic mice using compartmentalized cultures in microfluidic devices. We found that axonal BDNF increased dendritic growth from the neuronal cell body in a cAMP response element-binding protein (CREB)-dependent manner. These effects were dependent on axonal TrkB but not p75 activity. Dynein-dependent BDNF-TrkB-containing endosome transport was required for long-distance induction of dendritic growth. Axonal signaling endosomes increased CREB and mTOR kinase activity in the cell body, and this increase in the activity of both proteins was required for general protein translation and the expression of Arc, a plasticity-associated gene, indicating a role for BDNF-TrkB axonal signaling endosomes in coordinating the transcription and translation of genes whose products contribute to learning and memory regulation.
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Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico , Receptor trkB , Camundongos , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Receptor trkB/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Corpo Celular , Neurônios/fisiologia , Axônios/metabolismo , Endossomos/metabolismo , Serina-Treonina Quinases TOR/metabolismoRESUMO
Huntington's disease (HD) is caused by an expanded CAG repeat in the huntingtin gene, yielding a Huntingtin protein with an expanded polyglutamine tract. While experiments with patient-derived induced pluripotent stem cells (iPSCs) can help understand disease, defining pathological biomarkers remains challenging. Here, we used cryogenic electron tomography to visualize neurites in HD patient iPSC-derived neurons with varying CAG repeats, and primary cortical neurons from BACHD, deltaN17-BACHD, and wild-type mice. In HD models, we discovered sheet aggregates in double membrane-bound organelles, and mitochondria with distorted cristae and enlarged granules, likely mitochondrial RNA granules. We used artificial intelligence to quantify mitochondrial granules, and proteomics experiments reveal differential protein content in isolated HD mitochondria. Knockdown of Protein Inhibitor of Activated STAT1 ameliorated aberrant phenotypes in iPSC- and BACHD neurons. We show that integrated ultrastructural and proteomic approaches may uncover early HD phenotypes to accelerate diagnostics and the development of targeted therapeutics for HD.
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Doença de Huntington , Células-Tronco Pluripotentes Induzidas , Animais , Camundongos , Inteligência Artificial , Modelos Animais de Doenças , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Doença de Huntington/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Mitocôndrias/metabolismo , Neurônios/metabolismo , Fenótipo , Proteômica , HumanosRESUMO
Mutations or triplication of the alpha synuclein (ASYN) gene contribute to synucleinopathies including Parkinson's disease (PD), Dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Recent evidence suggests that ASYN also plays an important role in amyloid-induced neurotoxicity, although the mechanism(s) remains unknown. One hypothesis is that accumulation of ASYN alters endolysosomal pathways to impact axonal trafficking and processing of the amyloid precursor protein (APP). To define an axonal function for ASYN, we used a transgenic mouse model of synucleinopathy that expresses a GFP-human ASYN (GFP-hASYN) transgene and an ASYN knockout (ASYN-/-) mouse model. Our results demonstrate that expression of GFP-hASYN in primary neurons derived from a transgenic mouse impaired axonal trafficking and processing of APP. In addition, axonal transport of BACE1, Rab5, Rab7, lysosomes and mitochondria were also reduced in these neurons. Interestingly, axonal transport of these organelles was also affected in ASYN-/- neurons, suggesting that ASYN plays an important role in maintaining normal axonal transport function. Therefore, selective impairment of trafficking and processing of APP by ASYN may act as a potential mechanism to induce pathological features of Alzheimer's disease (AD) in PD patients.
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Doença de Parkinson , Sinucleinopatias , Humanos , Camundongos , Animais , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo , Secretases da Proteína Precursora do Amiloide , Precursor de Proteína beta-Amiloide/genética , Ácido Aspártico Endopeptidases , Doença de Parkinson/genética , Camundongos Transgênicos , Lisossomos/metabolismoRESUMO
Messenger RNA (mRNA) carries genetic instructions to the cell machinery for the transient production of antigens or therapeutic proteins and shows enormous potential in vaccine development, cancer immunotherapy, protein replacement therapy, and genome engineering. Here, the synthesis of chemically modified nerve growth factor mutant (NGFR100W ) mRNA through in vitro transcription is described. After the replacement of the original signal peptide sequence with the Ig Kappa leader sequence, codon-optimized NGFR100W mRNA yielded high secretion of mature NGFR100W , which promotes axon growth in PC12 cells. Using lipid nanoparticle (LNP)-delivery of N1-methylpseudouridine-modified mRNA in mice, NGFR100W -mRNA-LNPs result in the successful expression of NGFR100W protein, which significantly reduces nociceptive activity compared to that of NGFWT . This indicates that NGFR100W derived from exogenous mRNA elicited "painless" neuroprotective activity. Additionally, the therapeutic value of NGFR100W mRNA is established in a paclitaxel-induced peripheral neuropathy model by demonstrating the rapid recovery of intraepidermal nerve fibers. The results show that in vitro-transcribed mRNA has significant flexibility in sequence design and fast in vivo functional validation of target proteins. Furthermore, the results highlight the therapeutic potential of mRNA as a supplement to beneficial proteins for preventing or reversing some chronic medical conditions, such as peripheral neuropathy.
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Fator de Crescimento Neural , Doenças do Sistema Nervoso Periférico , Ratos , Camundongos , Animais , Fator de Crescimento Neural/genética , Fator de Crescimento Neural/metabolismo , RNA Mensageiro/metabolismo , LipossomosRESUMO
Rab7 GTPase regulates mitochondrial morphology and function. Missense mutation(s) of Rab7 underlies the pathogenesis of Charcot Marie Tooth 2B (CMT2B) peripheral neuropathy. Herein, we investigate how mitochondrial morphology and function are impacted by the CMT2B associated Rab7V162M mutation. In contrast to recent studies of using heterologous overexpression systems, our results demonstrate significant mitochondrial fragmentation in both human CMT2B patient fibroblasts and CMT2B embryonic fibroblasts (MEFs). Primary cultured E18 dorsal root ganglion (DRG) sensory neurons also show mitochondrial fragmentation and altered axonal mitochondrial movement. In addition, we demonstrate that inhibitors to either the mitochondrial fission protein Drp1 or to the nucleotide binding to Rab7 normalize the mitochondrial deficits in both MEFs and E18 cultured DRG neurons. Our study reveals, for the first time, that expression of CMT2B Rab7 mutation at the physiological level enhances Drp1 activity to promote mitochondrial fission, potentially underlying selective vulnerability of peripheral sensory neurons in CMT2B pathogenesis.
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Doença de Charcot-Marie-Tooth , Proteínas rab de Ligação ao GTP , Doença de Charcot-Marie-Tooth/genética , Humanos , Laminopatias , Mitocôndrias/metabolismo , Células Receptoras Sensoriais/metabolismo , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/metabolismo , proteínas de unión al GTP Rab7RESUMO
Synapse dysfunction and loss are central features of neurodegenerative diseases, caused in part by the accumulation of protein oligomers. Amyloid-ß, tau, prion, and α-synuclein oligomers bind to the cellular prion protein (PrPC), resulting in the activation of macromolecular complexes and signaling at the post-synapse, yet the early signaling events are unclear. Here we sought to determine the early transcript and protein alterations in the hippocampus during the pre-clinical stages of prion disease. We used a transcriptomic approach focused on the early-stage, prion-infected hippocampus of male wild-type mice, and identify immediate early genes, including the synaptic activity response gene, Arc/Arg3.1, as significantly upregulated. In a longitudinal study of male, prion-infected mice, Arc/Arg-3.1 protein was increased early (40% of the incubation period), and by mid-disease (pre-clinical), phosphorylated AMPA receptors (pGluA1-S845) were increased and metabotropic glutamate receptors (mGluR5 dimers) were markedly reduced in the hippocampus. Notably, sporadic Creutzfeldt-Jakob disease (sCJD) post-mortem cortical samples also showed low levels of mGluR5 dimers. Together, these findings suggest that prions trigger an early Arc response, followed by an increase in phosphorylated GluA1 and a reduction in mGluR5 receptors.
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Síndrome de Creutzfeldt-Jakob , Príons , Peptídeos beta-Amiloides/metabolismo , Animais , Síndrome de Creutzfeldt-Jakob/metabolismo , Hipocampo/metabolismo , Estudos Longitudinais , Masculino , Camundongos , Príons/metabolismoRESUMO
Ras and Rab interactor 3 (RIN3) functions as a Guanine nucleotide Exchange Factor (GEF) for some members of the Rab family of small GTPase. By promoting the activation of Rab5, RIN3 plays an important role in regulating endocytosis and endocytic trafficking. In addition, RIN3 activates Ras, another small GTPase, that controls multiple signaling pathways to regulate cellular function. Increasing evidence suggests that dysregulation of RIN3 activity may contribute to the pathogenesis of several disease conditions ranging from Paget's Disease of the Bone (PDB), Alzheimer's Disease (AD), Chronic Obstructive Pulmonary Disease (COPD) and to obesity. Recent genome-wide association studies (GWAS) identified variants in the RIN3 gene to be linked with these disease conditions. Interestingly, some variants appear to be missense mutations in the functional domains of the RIN3 protein while most variants are located in the noncoding regions of the RIN3 gene, potentially altering its gene expression. However, neither the protein structure of RIN3 nor its exact function(s) (except for its GEF activity) has been fully defined. Furthermore, how the polymorphisms/variants contribute to disease pathogenesis remain to be understood. Herein, we examine, and review published studies in an attempt to provide a better understanding of the physiological function of RIN3; More importantly, we construct a framework linking the polymorphisms/variants of RIN3 to altered cell signaling and endocytic traffic, and to potential disease mechanism(s).
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Pyroptosis is a novel programmed cell death process that promotes the release of interleukin-1ß (IL-1ß) and interleukin-18 (IL-18) by activating inflammasomes and gasdermin D (GSDMD), leading to cell swelling and rupture. Pyroptosis is involved in the regulation of the occurrence and development of cardiovascular and cerebrovascular diseases, tumors, and nerve injury. Diabetes is a metabolic disorder characterized by long-term hyperglycemia, insulin resistance, and chronic inflammation. The people have paid more and more attention to the relationship between pyroptosis, diabetes, and its complications, especially its important regulatory significance in diabetic neurological diseases, such as diabetic encephalopathy (DE) and diabetic peripheral neuropathy (DPN). This article will give an in-depth overview of the relationship between pyroptosis, diabetes, and its related neuropathy, and discuss the regulatory pathway and significance of pyroptosis in diabetes-associated neuropathy.
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Spinal cord injury (SCI) is one of the most debilitating of all the traumatic conditions that afflict individuals. For a number of years, extensive studies have been conducted to clarify the molecular mechanisms of SCI. Experimental and clinical studies have indicated that two phases, primary damage and secondary damage, are involved in SCI. The initial mechanical damage is caused by local impairment of the spinal cord. In addition, the fundamental mechanisms are associated with hyperflexion, hyperextension, axial loading and rotation. By contrast, secondary injury mechanisms are led by systemic and cellular factors, which may also be initiated by the primary injury. Although significant advances in supportive care have improved clinical outcomes in recent years, a number of studies continue to explore specific pharmacological therapies to minimize SCI. The present review summarized some important pathophysiologic mechanisms that are involved in SCI and focused on several pharmacological and nonpharmacological therapies, which have either been previously investigated or have a potential in the management of this debilitating injury in the near future.
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Traumatismos da Medula Espinal/tratamento farmacológico , Traumatismos da Medula Espinal/patologia , Animais , Inibidores de Ciclo-Oxigenase/farmacologia , Humanos , Minociclina/farmacologia , Fármacos Neuroprotetores/farmacologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/patologiaRESUMO
[This corrects the article DOI: 10.3389/fcell.2020.00602.].
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As a serious metabolic disease, diabetes causes series of complications that seriously endanger human health. The liver is a key organ for metabolizing glucose and lipids, which substantially contributes to the development of insulin resistance and type 2 diabetes mellitus (T2DM). Exogenous fibroblast growth factor 1 (FGF1) has a great potential for the treatment of diabetes. Receptor of advanced glycation end products (RAGE) is a receptor for advanced glycation end products that involved in the development of diabetes-triggered complications. Previous study has demonstrated that FGF1 significantly ameliorates diabetes-mediated liver damage (DMLD). However, whether RAGE is involved in this process is still unknown. In this study, we intraperitoneally injected db/db mice with 0.5 mg/kg FGF1. We confirmed that FGF1 treatment not only significantly ameliorates diabetes-induced elevated apoptosis in the liver, but also attenuates diabetes-induced inflammation, then contributes to ameliorate liver dysfunction. Moreover, we found that diabetes triggers the elevated RAGE in hepatocytes, and FGF1 treatment blocks it, suggesting that RAGE may be a key target during FGF1 treatment of diabetes-induced liver injury. Thus, we further confirmed the role of RAGE in FGF1 treatment of AML12 cells under high glucose condition. We found that D-ribose, a RAGE agonist, reverses the protective role of FGF1 in AML12 cells. These findings suggest that FGF1 ameliorates diabetes-induced hepatocyte apoptosis and elevated inflammation via suppressing RAGE pathway. These results suggest that RAGE may be a potential therapeutic target for the treatment of DMLD.
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Lesão Pulmonar Aguda/tratamento farmacológico , Complicações do Diabetes/tratamento farmacológico , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Tipo 2/complicações , Fator 1 de Crescimento de Fibroblastos/farmacologia , Inflamação/tratamento farmacológico , Receptor para Produtos Finais de Glicação Avançada/antagonistas & inibidores , Lesão Pulmonar Aguda/etiologia , Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/patologia , Animais , Apoptose , Complicações do Diabetes/etiologia , Complicações do Diabetes/metabolismo , Complicações do Diabetes/patologia , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Laser-induced shockwaves (LIS) can be utilized as a method to subject cells to conditions similar to those occurring during a blast-induced traumatic brain injury. The pairing of LIS with genetically encoded biosensors allows researchers to monitor the immediate molecular events resulting from such an injury. In this study, we utilized the genetically encoded Ca2+ FRET biosensor D3CPV to study the immediate Ca2+ response to laser-induced shockwave in cortical neurons and Schwann cells. Our results show that both cell types exhibit a transient Ca2+ increase irrespective of extracellular Ca2+ conditions. LIS allows for the simultaneous monitoring of the effects of shear stress on cells, as well as nearby cell damage and death.
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Prolonged type 2 diabetes mellitus (T2DM) produces a common complication, peripheral neuropathy, which is accompanied by nerve fiber disorder, axon atrophy, and demyelination. Growing evidence has characterized the beneficial effects of acidic fibroblast growth factor (aFGF) and shown that it relieves hyperglycemia, increases insulin sensitivity, and ameliorates neuropathic impairment. However, there is scarce evidence on the role of aFGF on remodeling of aberrant myelin under hyperglycemia condition. Presently, we observed that the expression of aFGF was rapidly decreased in a db/db T2DM mouse model. Administration of exogenous aFGF was sufficient to block acute demyelination and nerve fiber disorganization. Furthermore, this strong anti-demyelinating effect was most likely dominated by an aFGF-mediated increase of Schwann cell (SC) proliferation and migration as well as suppression of its apoptosis. Mechanistically, the beneficial biological effects of aFGF on SC behavior and abnormal myelin morphology were likely due to the inhibition of hyperglycemia-induced oxidative stress activation, which was most likely activated by kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid-derived-like 2 (Nrf2) signaling. Thus, this evidence indicates that aFGF is a promising protective agent for relieving myelin pathology through countering oxidative stress signaling cascades under diabetic conditions.