RESUMEN
Sepsis-associated encephalopathy (SAE) is a significant cause of mortality in patients with sepsis. Despite extensive research, its exact cause remains unclear. Our previous research indicated a relationship between non-hepatic hyperammonemia (NHH) and SAE. This study aimed to investigate the relationship between NHH and SAE and the potential mechanisms causing cognitive impairment. In the in vivo experimental results, there were no significant abnormalities in the livers of mice with moderate cecal ligation and perforation (CLP); however, ammonia levels were elevated in the hippocampal tissue and serum. The ELISA study suggest that fecal microbiota transplantation in CLP mice can reduce ammonia levels. Reduction in ammonia levels improved cognitive dysfunction and neurological impairment in CLP mice through behavioral, neuroimaging, and molecular biology studies. Further studies have shown that ammonia enters the brain to regulate the expression of aquaporins-4 (AQP4) in astrocytes, which may be the mechanism underlying brain dysfunction in CLP mice. The results of the in vitro experiments showed that ammonia up-regulated AQP4 expression in astrocytes, resulting in astrocyte damage. The results of this study suggest that ammonia up-regulates astrocyte AQP4 expression through the gut-brain axis, which may be a potential mechanism for the occurrence of SAE.
Asunto(s)
Acuaporina 4 , Astrocitos , Eje Cerebro-Intestino , Hiperamonemia , Encefalopatía Asociada a la Sepsis , Animales , Ratones , Acuaporina 4/metabolismo , Acuaporina 4/genética , Acuaporina 4/biosíntesis , Astrocitos/metabolismo , Hiperamonemia/metabolismo , Encefalopatía Asociada a la Sepsis/metabolismo , Masculino , Eje Cerebro-Intestino/fisiología , Ratones Endogámicos C57BL , Amoníaco/metabolismo , Amoníaco/sangre , Encéfalo/metabolismo , Trasplante de Microbiota FecalRESUMEN
Background: Ischemic stroke is one of the leading causes of human death and disability. Brain edema and peri-infarct astrocyte reactivity are crucial pathological changes, both involving aquaporin-4 (AQP4). Studies revealed that acute inhibition of AQP4 after stroke diminishes brain edema, however, its effect on peri-infarct astrocyte reactivity and the subacute outcome is unclear. And if diffusion-weighted imaging (DWI) could reflect the AQP4 expression patterns is uncertain. Methods: Rats were subjected to middle cerebral artery occlusion (MCAO) and allocated randomly to TGN 020-treated and control groups. One day after stroke, brain swelling and lesion volumes of the rats were checked using T2-weighted imaging (T2-WI). Fourteen days after stroke, the rats successively underwent neurological examination, T2-WI and DWI with standard b-values and ultra-high b-values, apparent diffusion coefficient (ADC) was calculated correspondingly. Finally, the rats' brains were acquired and used for glial fibrillary acidic protein (GFAP) and AQP4 immunoreactive analysis. Results: At 1 day after stroke, the TGN-020-treated animals exhibited reduced brain swelling and lesion volumes compared with those in the control group. At 14 days after stroke, the TGN-020-treated animals showed fewer neurological function deficits and smaller lesion volumes. In the peri-infarct region, the control group showed evident astrogliosis and AQP4 depolarization, which were reduced significantly in the TGN-020 group. In addition, the ultra-high b-values of ADC (ADCuh) in the peri-infarct region of the TGN-020 group was higher than that of the control group. Furthermore, correlation analysis revealed that peri-infarct AQP4 polarization correlated negatively with astrogliosis extent, and ADCuh correlated positively with AQP4 polarization. Conclusion: We found that acutely inhibiting AQP4 using TGN-020 promoted neurological recovery by diminishing brain edema at the early stage and attenuating peri-infarct astrogliosis and AQP4 depolarization at the subacute stage after stroke. Moreover, ADCuh could reflect the AQP4 polarization.
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Edema Encefálico , Gliosis , Infarto de la Arteria Cerebral Media , Animales , Acuaporina 4/biosíntesis , Edema Encefálico/diagnóstico por imagen , Edema Encefálico/metabolismo , Edema Encefálico/patología , Edema Encefálico/prevención & control , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Gliosis/diagnóstico por imagen , Gliosis/metabolismo , Gliosis/patología , Gliosis/prevención & control , Infarto de la Arteria Cerebral Media/diagnóstico por imagen , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Infarto de la Arteria Cerebral Media/metabolismo , Infarto de la Arteria Cerebral Media/patología , Imagen por Resonancia Magnética , Niacinamida/análogos & derivados , Niacinamida/uso terapéutico , Ratas , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/tratamiento farmacológico , Accidente Cerebrovascular/metabolismo , Accidente Cerebrovascular/patología , Tiadiazoles/uso terapéuticoRESUMEN
The predominant form of edema that occurs during the early stage of ischemic stroke is cytotoxic, resulting in neuronal injury during brain ischemia and reperfusion. Intracellular calcium (Ca2+) is elevated following brain ischemia leading to increased cell membrane permeability. Ca2+/calmodulin-dependent protein kinase II (CaMK II), the downstream molecular signal of N-methyl-d-aspartate receptors (NMDARs), is sensitive to elevations in intracellular Ca2+. Aquaporin-4 (AQP4), which is expressed primarily in the brain, is a water-transport protein. However, it is unclear whether CaMK II regulates AQP4 expression to modulate cellular water permeability. We exposed cultured astrocytes to a hypoxic and glucose-free environment to mimic an ischemic environment in vitro. We investigated the effects of oxygen-glucose deprivation (OGD) on astrocytic viability and swelling, as well as CaMK II and AQP4 expression. We also studied the effects of CaMK II inhibition on cell swelling, viability and AQP4 expression. OGD increased astrocytic swelling and expression of CaMK II and AQP4, and it decreased astrocyte viability. Inhibition of CaMK II resulted in reduced astrocyte water permeability and AQP4 expression. We concluded that the upregulation of CaMK II promoted astrocyte swelling by increasing the expression of AQP4 after OGD.
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Acuaporina 4/biosíntesis , Astrocitos/metabolismo , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Hipoxia de la Célula/fisiología , Glucosa/deficiencia , Agua/metabolismo , Animales , Animales Recién Nacidos , Acuaporina 4/antagonistas & inhibidores , Acuaporina 4/genética , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/antagonistas & inhibidores , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/genética , Permeabilidad de la Membrana Celular/fisiología , Células Cultivadas , Expresión Génica , Técnicas de Silenciamiento del Gen/métodos , Oxígeno/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Concentrated conditioned media from adipose tissue-derived mesenchymal stem cells (ASC-CCM) show promise for retinal degenerative diseases. In this study, we hypothesized that ASC-CCM could rescue retinal damage and thereby improve visual function by acting through Müller glia in mild traumatic brain injury (mTBI). Adult C57Bl/6 mice were subjected to a 50-psi air pulse on the left side of the head, resulting in an mTBI. After blast injury, 1 µL (â¼100 ng total protein) of human ASC-CCM was delivered intravitreally and followed up after 4 weeks for visual function assessed by electroretinogram and histopathological markers for Müller cell-related markers. Blast mice that received ASC-CCM, compared with blast mice that received saline, demonstrated a significant improvement in a- and b-wave response correlated with a 1.3-fold decrease in extracellular glutamate levels and a concomitant increase in glutamine synthetase (GS), as well as the glutamate transporter (GLAST) in Müller cells. Additionally, an increase in aquaporin-4 (AQP4) in Müller cells in blast mice received saline restored to normal levels in blast mice that received ASC-CCM. In vitro studies on rMC-1 Müller glia exposed to 100 ng/mL glutamate or RNA interference knockdown of GLAST expression mimicked the increased Müller cell glial fibrillary acidic protein (a marker of gliosis) seen with mTBI, and suggested that an increase in glutamate and/or a decrease in GLAST might contribute to the Müller cell activation in vivo. Taken together, our data suggest a novel neuroprotective role for ASC-CCM in the rescue of the visual deficits and pathologies of mTBI via restoration of Müller cell health.
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Conmoción Encefálica , Medios de Cultivo Condicionados/farmacología , Células Madre Mesenquimatosas/metabolismo , Retina/efectos de los fármacos , Sistema de Transporte de Aminoácidos X-AG/biosíntesis , Animales , Acuaporina 4/biosíntesis , Traumatismos por Explosión/patología , Conmoción Encefálica/complicaciones , Células Ependimogliales/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Glutamato-Amoníaco Ligasa/biosíntesis , Humanos , Ratones , Ratones Endogámicos C57BL , Fármacos Neuroprotectores/farmacología , Retina/patología , Trastornos de la Visión/etiologíaRESUMEN
Stroke is one of the leading causes of mortality and disability worldwide. Long noncoding RNAs (lncRNAs) including MALAT1 have been shown to have critical roles in cerebral ischemia reperfusion injury (CIRI). However, the underlying mechanism of MALAT1 in CIRI has not been elucidated. The present study aimed to investigate the function and potential regulatory mechanism of MALAT1 in cerebral ischemic reperfusion injury. We established the middle cerebral artery occlusion (MCAO) model and oxygen-glucose deprivation/reoxygenation (OGD/RX) model in vivo and in vitro, and then Cell Counting Kit-8 (CCK-8), RT-qPCR, flow cytometry analysis, lactate dehydrogenase (LDH) analysis, and 2,3,5-triphenyltetrazolium chloride (TTC) staining were used to examine cell viability, MALAT1, aquaporin-4 (AQP4) expression, LDH release, and infarct volume, respectively. The level of AQP4 was remarkably upregulated in CIRI 24 h/48 h or OGD/RX 24 h/48 h compared with the sham group. Knockdown of AQP4 could alleviate OGD/RX-induced injury through enhancing cell viability and reducing LDH release and the rate of apoptotic cells. Furthermore, we found that MALAT1 was also increased in OGD/RX 24 h/48 h and silencing of MALAT1 could decrease AQP4. Inhibition of MALAT1 could also protect OGD/RX-induced injury, while the protective effect of MALAT1 siRNA on cerebral ischemic reperfusion was disappeared after transfection with AQP4 plasmid, indicating that MALAT1 may play a protective role in brain stroke through regulating AQP4. Taken together, our study provides evidence that MALAT1 is involved in ischemic stroke by inhibiting AQP4. Therefore, MALAT1 may serve as a potential target for therapeutic intervention in ischemic brain injury.
Asunto(s)
Acuaporina 4/biosíntesis , Accidente Cerebrovascular Isquémico/metabolismo , ARN Largo no Codificante/metabolismo , Daño por Reperfusión/metabolismo , Animales , Regulación de la Expresión Génica/fisiología , Accidente Cerebrovascular Isquémico/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Daño por Reperfusión/patologíaRESUMEN
The present study was designed to determine the effect of different doses of oxytocin (OXT) on neuronal injury, spatial memory, blood-brain barrier (BBB) integrity and to explore possible underlying molecular mechanisms in the early stage of stroke in mice. Stroke model was generated by middle cerebral artery occlusion (MCAO) for 60 min and 24 h reperfusion in mice. OXT at doses of 1, 2, 4 and 8 IU/per mouse was administrated intranasally at the beginning of brain ischemia. Brain injury, BBB integrity, and spatial memory were evaluated by standard methods. Changes in the expression of nuclear factor-kappa B (NF-κB), and TUNEL positive cell were detected by immunohistochemistry. The levels of vascular endothelial growth factor (VEGF), aquaporin-4 (AQP4) and brain-derived neurotrophic factor (BDNF) proteins were determined by western blotting and ELISA methods. OXT at doses of 4 and 8 IU/per mouse reduced the infarct size by 42% and 52%, respectively, and improved spatial memory function (p < 0.001). OXT (8 IU/per mouse) significantly reduced brain edema, BBB disruption and upregulated the AQP4 expression (p < 0.001). Finally, OXT significantly diminished the number of apoptotic, NF-κB positive cells and enhanced the expression of BDNF and VEGF proteins in the brain tissue (p < 0.001). These findings provide important evidences that OXT significantly suppresses neuronal damage in the early stage of stroke by inhibiting apoptotic and NF-κB signaling pathway, increasing the expression of VEGF, AQP4 and BDNF proteins and reducing the BBB leakage.
Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Oxitocina/uso terapéutico , Animales , Acuaporina 4/análisis , Acuaporina 4/biosíntesis , Acuaporina 4/genética , Edema Encefálico/tratamiento farmacológico , Edema Encefálico/etiología , Factor Neurotrófico Derivado del Encéfalo/análisis , Infarto Cerebral/etiología , Infarto Cerebral/patología , Etiquetado Corte-Fin in Situ , Masculino , Ratones , FN-kappa B/metabolismo , Proteínas del Tejido Nervioso/análisis , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/genética , Oxitocina/farmacología , Transducción de Señal , Método Simple Ciego , Memoria Espacial/efectos de los fármacos , Factor A de Crecimiento Endotelial Vascular/análisisRESUMEN
Brain edema following brain infarction affects mobility and mortality. The mechanisms underlying this process remain to be elucidated. Animal studies have shown that aquaporin-4 (AQP4) expression in astrocytes increases after stroke, and its deletion significantly reduces brain swelling. Recently, two kinds of cells, resident microglia-derived macrophage-like cells (MG-MΦ) and bone marrow-derived macrophages (BM-MΦ), have been reported to accumulate in the ischemic core and stimulate adjacent astrocytes. Therefore, we hypothesized that these cells play crucial roles in the expression of AQP4 and ultimately lead to exacerbated brain edema. To verify this hypothesis, we investigated the role of MG- or BM-MΦ in brain edema using a rat model of transient middle cerebral artery occlusion and rat astrocyte primary cultures. AQP4 expression significantly increased in the peri-infarct tissue at 3-7 days post-reperfusion (dpr) and in the core tissue at 5 and 7 dpr, which synchronized with the expression of Iba1, Il1a, Tnf, and C1qa mRNA. Interleukin (IL)-1α treatment or coculture with MG- and BM-MΦ increased AQP4 expression in astrocytes, while an IL-1 receptor type I antagonist reduced these effects. Furthermore, aggravated animals exhibited high expression of Aqp4 and Il1a mRNA in the ischemic core at 7 dpr, which led to the exacerbation of brain edema. MG-MΦ signature genes were highly expressed in the ischemic core in aggravated rats, while BM-MΦ signature genes were weakly expressed. These findings suggest that IL-1α produced by MG-MΦ induces astrocytic AQP4 expression in the peri-infarct and ischemic core tissues, thereby exacerbating brain edema. Therefore, the regulation of MG-MΦ may prevent the exacerbation of brain edema.
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Acuaporina 4/biosíntesis , Astrocitos/metabolismo , Edema Encefálico/metabolismo , Interleucina-1alfa/biosíntesis , Accidente Cerebrovascular Isquémico/metabolismo , Macrófagos/metabolismo , Microglía/metabolismo , Animales , Acuaporina 4/genética , Edema Encefálico/genética , Isquemia Encefálica/genética , Isquemia Encefálica/metabolismo , Células Cultivadas , Expresión Génica , Células HEK293 , Humanos , Interleucina-1alfa/genética , Accidente Cerebrovascular Isquémico/genética , Masculino , Ratas , Ratas WistarAsunto(s)
Acuaporina 4/biosíntesis , Enfermedades Desmielinizantes/sangre , Regulación Neoplásica de la Expresión Génica , Gammopatía Monoclonal de Relevancia Indeterminada/sangre , Proteínas de Neoplasias/biosíntesis , Síndromes Paraneoplásicos del Sistema Nervioso/sangre , Enfermedad Aguda , Enfermedades Desmielinizantes/patología , Femenino , Humanos , Persona de Mediana Edad , Gammopatía Monoclonal de Relevancia Indeterminada/patología , Síndromes Paraneoplásicos del Sistema Nervioso/patologíaRESUMEN
BACKGROUND: Specific highly polarized aquaporin-4 (AQP4) expression is reported to play a crucial role in blood-brain barrier (BBB) integrity and brain water transport balance. The upregulation of polymerase δ-interacting protein 2 (Poldip2) was involved in aggravating BBB disruption following ischemic stroke. This study aimed to investigate whether Poldip2-mediated BBB disruption and cerebral edema formation in mouse bacterial meningitis (BM) model occur via induction of AQP4 polarity loss. METHODS AND RESULTS: Mouse BM model was induced by injecting mice with group B hemolytic streptococci via posterior cistern. Recombinant human Poldip2 (rh-Poldip2) was administered intranasally at 1 hour after BM induction. Small interfering ribonucleic acid (siRNA) targeting Poldip2 was administered by intracerebroventricular (i.c.v) injection at 48 hours before BM induction. A specific inhibitor of matrix metalloproteinases (MMPs), UK383367, was administered intravenously at 0.5 hour before BM induction. Western blotting, immunofluorescence staining, quantitative real-time PCR, neurobehavioral test, brain water content test, Evans blue (EB) permeability assay, transmission electron microscopy (TEM), and gelatin zymography were carried out. The results showed that Poldip2 was upregulated and AQP4 polarity was lost in mouse BM model. Both Poldip2 siRNA and UK383367 improved neurobehavioral outcomes, alleviated brain edema, preserved the integrity of BBB, and relieved the loss of AQP4 polarity in BM model. Rh-Poldip2 upregulated the expression of MMPs and glial fibrillary acidic protein (GFAP) and downregulated the expression of ß-dystroglycan (ß-DG), zonula occludens-1 (ZO-1), occludin, and claudin-5; whereas Poldip2 siRNA downregulated the expression of MMPs and GFAP, and upregulated ß-DG, ZO-1, occludin, and claudin-5. Similarly, UK383367 downregulated the expression of GFAP and upregulated the expression of ß-DG, ZO-1, occludin, and claudin-5. CONCLUSION: Poldip2 inhibition alleviated brain edema and preserved the integrity of BBB partially by relieving the loss of AQP4 polarity via MMPs/ß-DG pathway.
Asunto(s)
Acuaporina 4/biosíntesis , Barrera Hematoencefálica/metabolismo , Edema Encefálico/metabolismo , Modelos Animales de Enfermedad , Meningitis Bacterianas/metabolismo , Proteínas Mitocondriales/biosíntesis , Proteínas Nucleares/biosíntesis , Administración Intranasal , Animales , Acuaporina 4/genética , Barrera Hematoencefálica/patología , Edema Encefálico/genética , Edema Encefálico/patología , Humanos , Masculino , Meningitis Bacterianas/genética , Meningitis Bacterianas/patología , Ratones , Proteínas Mitocondriales/deficiencia , Proteínas Mitocondriales/genética , Proteínas Nucleares/deficiencia , Proteínas Nucleares/genéticaRESUMEN
Dexamethasone can alleviate the severity of bronchial and alveolar edema and therefore is widely applied in the treatment of various exudative diseases including pulmonary edema. However, the effectiveness of dexamethasone is still being questioned and its mechanism is not fully understood. Aquaporins (AQPs) are mainly responsible for the transmembrane transport of water, which is tightly associated with pulmonary edema. Small ubiquitin-like modifiers (SUMOs) are considered to play a protective role in some pathological conditions. In this study, we demonstrated that dexamethasone can upregulate the expression of AQPs in A549 cells by inducing SUMOylation. We found that a low dose of dexamethasone significantly upregulated the levels of SUMOylation and AQP expression in A549 cells, accompanied by a translocation of SUMOs from the cytoplasm to the nucleus. We also explored the possible relation between SUMOylation and AQPs. Knockdown of SUMO2/3 by RNA interference decreased the level of AQP4 in A549 cells after dexamethasone stimulation. Together, our findings demonstrated that AQP4 expression was upregulated in A549 cells exposed to dexamethasone, and SUMOylation may participate in the regulation of AQP4.
Asunto(s)
Antiinflamatorios/farmacología , Acuaporina 4/biosíntesis , Dexametasona/farmacología , Mucosa Respiratoria/metabolismo , Sumoilación/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Células A549 , Acuaporina 4/genética , Relación Dosis-Respuesta a Droga , Expresión Génica , Humanos , Mucosa Respiratoria/efectos de los fármacos , Sumoilación/fisiología , Regulación hacia Arriba/fisiologíaRESUMEN
OBJECTIVES: To observe glymphatic transport and evaluate enlarged perivascular spaces (PVSs) in spontaneously hypertensive rats (SHRs). METHODS: SHRs were used as an animal model of cerebral small vessel disease, and Wistar Kyoto (WKY) rats were used as the control group. Histopathology was used to evaluate the enlargement of PVSs. A fluorescent tracer was infused into the cisterna magna of rats, and the proportion of the brain parenchyma area exposed to the fluorescent tracer was later quantified to evaluate the influx and efflux function of the glymphatic system. The global and polarized expression of aquaporin protein 4 (AQP4) was analyzed by immunofluorescence. RESULTS: Compared with WKY rats, SHRs exhibited obviously enlarged PVSs and significantly decreased influx and efflux function of the glymphatic system. The results showed a significant decrease in AQP4 polarity in SHRs, but a difference in global AQP4 expression was not observed between SHRs and WKY rats. CONCLUSIONS: Impaired glymphatic transport may be involved in the pathogenesis of arteriolosclerotic cerebral small vessel disease, and enlarged PVSs may be a manifestation of the impaired glymphatic system.
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Enfermedades de los Pequeños Vasos Cerebrales/patología , Modelos Animales de Enfermedad , Sistema Glinfático/patología , Hipertensión/patología , Arteriosclerosis Intracraneal/patología , Animales , Acuaporina 4/biosíntesis , Enfermedades de los Pequeños Vasos Cerebrales/metabolismo , Sistema Glinfático/metabolismo , Hipertensión/metabolismo , Arteriosclerosis Intracraneal/metabolismo , Masculino , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKYRESUMEN
OBJECTIVES: In the skeletal muscles, water metabolism is mainly regulated by water channel aquaporin 4 (AQP4). Although the expression level of AQP4 was reduced by long-term denervation, during denervation the relationship between muscle atrophy initiation and AQP4 expression decrease initiation remains unknown. The present study examined the relationship between the timing of muscle atrophy initiation and that of AQP4 expression decrease initiation, during the early stage of denervation. METHODS: Female 344 rats (8 weeks of age) were randomly assigned to control (C), day 1 post-sciatic denervation (D1), day 4 post- sciatic denervation (D4) and day 7 post- sciatic denervation (D7) groups (n=6 per group). In the tibialis anterior (TA) muscles of each group, the expression levels of some target proteins were quantified by Western blot analysis. RESULTS: The expression level of AQP4 significantly decreased on day 4 post-denervation (p<0.05). Moreover, the beginning of the decrease in AQP4 expression level was concurrent with the timing of muscle atrophy in the skeletal muscles during the early stage of denervation. CONCLUSIONS: The present study suggested that the progression of the decrease in the AQP4 expression level is partly related to the progression of muscle atrophy during the early stage of denervation.
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Acuaporina 4/biosíntesis , Desnervación Muscular/tendencias , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Animales , Acuaporina 4/genética , Femenino , Expresión Génica , Desnervación Muscular/métodos , Músculo Esquelético/patología , Atrofia Muscular/patología , Ratas , Ratas Endogámicas F344 , Factores de TiempoRESUMEN
This study aimed to investigate the underlying pathological muscle damage in neuromyelitis optica spectrum disorder (NMOSD) patients without muscular symptoms. We prospectively enrolled 15 patients with aquaporin 4 (AQP4) antibody seropositive NMOSD and 16 patients with non-NMOSD diseases as a control group. Biceps biopsy samples from 18 patients were examined. Six NMOSD patients exhibited inflammatory lesions/edema in lower muscles on muscle MRI. On histopathological examination, NMOSD samples showed significantly decreased IgG-targeting AQP4 expression on sarcolemma compared with non-NMOSD samples in terms of the area of positive staining and integrated optical density. Muscle biopsy can support the differential diagnosis of NMOSD.
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Acuaporina 4/sangre , Neuromielitis Óptica/sangre , Neuromielitis Óptica/diagnóstico por imagen , Sarcolema/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Acuaporina 4/biosíntesis , Acuaporina 4/genética , Diagnóstico Diferencial , Femenino , Expresión Génica , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/metabolismo , Neuromielitis Óptica/genética , Estudios Prospectivos , Sarcolema/genéticaRESUMEN
BACKGROUND: Spinal cord ischemia-reperfusion injury (SCII) is a common complication of spinal surgery as well as thoracic and abdominal surgery. Acute cytotoxic edema is the key pathogenic alteration. Therefore, avoiding or decreasing cellular edema has become the major target for SCII treatment. METHODS: The antiedema activity of ginsenoside Rb1 on aquaporin (AQP) 4, nerve growth factor (NGF), and brain-derived neurotrophic factor expression was detected by western blot and real-time polymerase chain reaction under conditions of oxygen-glucose deprivation/reoxygenation (OGD/R) in a rat astrocyte model in vitro. In addition, the cellular membrane permeability of AQP4 overexpressing cells or AQP4 small interfering RNA-transfected cells was detected. RESULTS: Ginsenoside Rb1 significantly prevented OGD/R-induced AQP4 downregulation in rat astrocytes. In addition, ginsenoside Rb1 treatment or AQP4 overexpression in rat astrocytes significantly attenuated the OGD/R-induced increase of cellular membrane permeability. Moreover, ginsenoside Rb1 obviously prevented the OGD/R-induced decrease of NGF and BDNT expression in rat astrocytes. CONCLUSION: These findings demonstrate that ginsenoside Rb1 can relieve spinal cord edema and improve neurological function by increasing AQP4 expression.
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Acuaporina 4/genética , Astrocitos/metabolismo , Regulación del Desarrollo de la Expresión Génica , Ginsenósidos/farmacología , Glucosa/metabolismo , Oxígeno/metabolismo , Daño por Reperfusión/genética , Animales , Animales Recién Nacidos , Acuaporina 4/biosíntesis , Astrocitos/efectos de los fármacos , Astrocitos/patología , Western Blotting , Células Cultivadas , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , ARN/genética , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/tratamiento farmacológico , Daño por Reperfusión/patología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Médula Espinal/metabolismo , Médula Espinal/patologíaRESUMEN
Aquaporin (AQP4) could be associated with inflammation, common in central nervous system diseases. We investigated the effect of lipoxin A4 (LXA4) on the activation of astrocytes, AQP4 expression, and inflammatory response induced by lipopolysaccharide (LPS). Astrocytes were cultured in vitro and changes in transcript and protein levels of AQP4, interleukin-1ß (IL-1ß), tumor necrosis factor-alpha (TNF-α), and cyclooxygenase-2 (COX-2), and protein levels of P38 and phospho-P38 were determined. The LPS group showed increased AQP4, IL-1ß, TNF-α, and COX-2 levels, whereas they decreased in the LPSâ¯+â¯LXA4 group, suggesting that LXA4 inhibits AQP4 expression. Furthermore, levels of phospho-P38 increased in the LPS group, but decreased in the LPSâ¯+â¯LXA4 group. In conclusion, LXA4 alleviated the LPS-induced increase in AQP4 expression and inflammatory cytokine secretion by astrocytes, possibly by inhibiting P38 phosphorylation. For the first time, we found that LXA4 may inhibit the expression of inflammatory factors by regulating the expression of AQP4. AQP4 on astrocytes is likely to be the target of anti-inflammatory effect of LXA4.
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Acuaporina 4/biosíntesis , Astrocitos/metabolismo , Lipoxinas/fisiología , Animales , Astrocitos/inmunología , Células Cultivadas , Citocinas/metabolismo , Mediadores de Inflamación/metabolismo , Lipopolisacáridos/inmunología , Ratones Endogámicos BALB C , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
Astrocytes serve many functions in the human brain, many of which focus on maintenance of homeostasis. Astrocyte dysfunction in Tuberous Sclerosis Complex (TSC) has long been appreciated with activation of the mTORC1 signaling pathway resulting in gliosis and possibly contributing to the very frequent phenotype of epilepsy. We hypothesized that aberrant expression of the astrocyte protein aquaporin-4 (AQP4) may be present in TSC and contribute to disease pathology. Characterization of AQP4 expression in epileptic cortex from TSC patients demonstrated a diffuse increase in AQP4. To determine if this was due to exposure to seizures, we examined Aqp4 expression in mouse models of TSC in which Tsc1 or Tsc2 inactivation was targeted to astrocytes or glial progenitors, respectively. Loss of either Tsc1 or Tsc2 from astrocytes resulted in a marked increase in Aqp4 expression which was sensitive to mTORC1 inhibition with rapamycin. Our findings in both TSC epileptogenic cortex and in a variety of astrocyte culture models demonstrate for the first time that AQP4 expression is dysregulated in TSC. The extent to which AQP4 contributes to epilepsy in TSC is not known, though the similarities in AQP4 expression between TSC and temporal lobe epilepsy supports further studies targeting AQP4 in TSC.
Asunto(s)
Acuaporina 4/biosíntesis , Astrocitos/metabolismo , Corteza Cerebral/metabolismo , Convulsiones/metabolismo , Esclerosis Tuberosa/metabolismo , Adolescente , Animales , Niño , Preescolar , Femenino , Humanos , Recién Nacido , Masculino , Ratones , Ratones Noqueados , Persona de Mediana Edad , Convulsiones/etiología , Esclerosis Tuberosa/complicacionesRESUMEN
Isoflurane is commonly used in pediatric population, but its mechanism of action in cognition is unclear. Aquaporin 4 (AQP4) regulates water content in blood, brain, and cerebrospinal fluid. Various studies have provided evidence for the role of AQP4 in synaptic plasticity and neurocognition. In this study, we aimed to determine whether a prolonged exposure to isoflurane in infant rats is associated with cognition and what effect this exposure has on AQP4 expression. Ten-day-old [postnatal day (P) 10] Wistar albino rats were randomly allocated to isoflurane group (n = 32; 1.5% isoflurane in 50% oxygen for 6 hours) or control group (n = 32; only 50% oxygen for 6 hours). Acute (P11) and long-term (P33) effects of 6-hour anesthetic isoflurane exposure on AQP4 expression were analyzed in whole brains of P11 and P33 rats by RT-qPCR and Western blot. Spatial learning and memory were assessed on P28 to P33 days by Morris Water Maze (MWM) test. The analysis revealed that isoflurane increased acutely both mRNA (~4.5 fold) and protein (~90%) levels of AQP4 in P11 rats compared with control group. The increasing levels of AQP4 in P11 were not observed in P33 rats. Also, no statistically significant change between isoflurane and control groups was observed in the latency to find the platform during MWM training and probe trial. Our results indicate that a single exposure to isoflurane anesthesia does not influence cognition in infant rats. In this case, acutely increased AQP4 after isoflurane anesthesia may have a protective role in neurocognition.
Asunto(s)
Anestésicos por Inhalación/toxicidad , Acuaporina 4/biosíntesis , Disfunción Cognitiva/inducido químicamente , Disfunción Cognitiva/psicología , Isoflurano/toxicidad , Animales , Química Encefálica/efectos de los fármacos , Femenino , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Memoria/efectos de los fármacos , ARN Mensajero/biosíntesis , Ratas , Ratas Wistar , Aprendizaje Espacial/efectos de los fármacosRESUMEN
The blood-spinal cord barrier (BSCB) changes badly after spinal cord injury (SCI), and it is an important pathophysiological basis of SCI secondary damage. Aquaporin-4 (AQP4), one of the transmembrane proteins in spinal cord, has been shown to be closely related to the development of the BSCB and edema. We established a SCI model in rats using a free-falling weight drop device to subsequently investigate AQP4 expression. AQP4 messenger RNA (mRNA) and protein expression and immunoreactivity were detected in spinal cord tissue using reverse transcription-real-time quantitative polymerase chain reaction (RT-qPCR), immunohistochemistry and Western blot analysis. We found the water content and edema of the spinal cord were significantly higher than the control group after SCI, which was related to the growth of BSCB permeability; both reached their peak on the third day after injury. One, 3, 5, 7 days after injury, the immune response and protein expression in the model group increased from 1 to 3 days, with a plateau period from 3 to 5 days and a decline from 5 to 7 days, showing a significant difference compared with the sham group at each time point (P < 0.05), while the RT-qPCR results showed a decline of mRNA just after 3 days. In conclusion, after SCI, the water content of the spinal cord and the BSCB permeability increases, together with the excessive expression of AQP4, which reached a peak on the third day. AQP4 expression is closely relative to the permeability of BSCB and the water content of the spinal cord.
Asunto(s)
Acuaporina 4/biosíntesis , Barrera Hematoencefálica/metabolismo , Encéfalo/metabolismo , Traumatismos de la Médula Espinal/metabolismo , Médula Espinal/metabolismo , Animales , Acuaporina 4/genética , Barrera Hematoencefálica/patología , Encéfalo/patología , Permeabilidad Capilar/fisiología , Femenino , Expresión Génica , Ratas , Ratas Sprague-Dawley , Médula Espinal/patología , Traumatismos de la Médula Espinal/patologíaRESUMEN
Ischemic stroke occurs through embolic or thrombotic obliteration of an artery from cerebral circulation and represents over 80% of all stroke cases. One of the fiercest complications after stroke is edema, which results from imbalanced water diffusion around the blood vessels walls. Water diffusion around blood vessel walls occurs physiologically mainly through two protein-formed pores, namely aquaporins (AQPs) 1 and 4. Here, we compare for the first time the expression patterns and colocalization degrees of the two AQPs in control brain tissue and in peri-ischemic regions, on tissue obtained from eight patients with confirmed ischemic pathology and from five control cases. Our analysis showed that AQP4 is more abundant that AQP1, especially in the cortex and in the organized scar areas. The colocalization of the two markers was high, both located on the astrocytes membranes, but the colocalization degree decreased in the scar peri-ischemic regions. Colocalization with basement membranes was also lower for AQP1 compared to AQP4, in all regions analyzed.
Asunto(s)
Acuaporina 1/biosíntesis , Acuaporina 4/biosíntesis , Accidente Cerebrovascular/metabolismo , Anciano , Acuaporina 1/genética , Acuaporina 4/genética , Membrana Basal/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Accidente Cerebrovascular/genética , Accidente Cerebrovascular/patologíaRESUMEN
The present research was designed to study expression of AQP2, AQP4 and AQP8 in mouse intestines induced by unprocessed and processed Euphorbia lathyris. KM mice were given by different dose lavage of unprocessed and processed Euphorbia lathyris, Euphorbia factor L1, Euphorbia factor L2, Euphorbia factor L3. Samples of mouse intestine were collected for protein levels of AQP2, AQP 4 and AQP 8 which were assessed by immunohistochemical staining and mRNA expression of AQP2, AQP 4 and AQP 8 which were quantified by Real Time-PCR. Comparing to the normal control group, the protein levels of AQP2, AQP 4 and AQP 8 were significantly decreased (P<0.05)by Semen Euphorbiae group and Semen Euphorbiae Pulveratum group (unprocessed and processed Euphorbia lathyris) induced. Protein expression of AQP2, AQP 4 and AQP 8 in the Euphorbia factor L1, Euphorbia factor L2 and Euphorbia factor L3 group were not significantly lower than normal control group. There had no differences on the levels of AQP2 and AQP 8 mRNA expressions between the high-dose group of semen Euphorbiae group, semen Euphorbiae Pulveratum group and positive control group, while significantly lower than normal control group (P<0.05). Expression of AQP4 mRNA in the Semen Euphorbiae group and Semen Euphorbiae Pulveratum group has not significantly decreased. But levels of AQP2, AQP 4 and AQP 8 mRNA in the Euphorbia factor L1 group had no significant differences in normal control group and positive control group. These findings suggest that semen Euphorbiae could regulate expression of AQP2, AQP 4 and AQP 8 protein and mRNA, which may be the possible one reason of semen Euphorbiae induces diarrhea. The semen Euphorbiae group has more significant effects on the levels of AQP2, AQP 4 and AQP 8 protein and mRNA than semen Euphorbiae Pulveratum group, which may be one of the mechanisms of processing attenuation.