Neuroglobin Facilitates Neuronal Oxygenation through Tropic Migration under Hypoxia or Anemia in Rat: How Does the Brain Breathe? / 神经科学通报·英文版

The discovery of neuroglobin (Ngb), a brain- or neuron-specific member of the hemoglobin family, has revolutionized our understanding of brain oxygen metabolism. Currently, how Ngb plays such a role remains far from clear. Here, we report a novel mechanism by which Ngb might facilitate neuronal oxygenation upon hypoxia or anemia. We found that Ngb was present in, co-localized to, and co-migrated with mitochondria in the cell body and neurites of neurons. Hypoxia induced a sudden and prominent migration of Ngb towards the cytoplasmic membrane (CM) or cell surface in living neurons, and this was accompanied by the mitochondria. In vivo, hypotonic and anemic hypoxia induced a reversible Ngb migration toward the CM in cerebral cortical neurons in rat brains but did not alter the expression level of Ngb or its cytoplasm/mitochondria ratio. Knock-down of Ngb by RNA interference significantly diminished respiratory succinate dehydrogenase (SDH) and ATPase activity in neuronal N2a cells. Over-expression of Ngb enhanced SDH activity in N2a cells upon hypoxia. Mutation of Ngb at its oxygen-binding site (His64) significantly increased SDH activity and reduced ATPase activity in N2a cells. Taken together, Ngb was physically and functionally linked to mitochondria. In response to an insufficient oxygen supply, Ngb migrated towards the source of oxygen to facilitate neuronal oxygenation. This novel mechanism of neuronal respiration provides new insights into the understanding and treatment of neurological diseases such as stroke and Alzheimer's disease and diseases that cause hypoxia in the brain such as anemia.

Comparative study of the distribution and expression of Neuroglobin and Hypoxia-inducible factor-1α in the adult and young Yak Brain / Estudo comparativo da distribuição e expressão de neuroglobina e fator-1α indutível por hipóxia em adultos e jovens iaques (Yak Brain)

Background: The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. Aim: The study examined the expression of Neuroglobin (Ngb) and Hypoxia-inducible factor-1α (Hif-1α) in adult and young yak brain tissues, and provided researchers with meaningful insight into the anatomy, physiology, and biochemistry of this mammal. Method: The study employed immunohistochemistry (IHC), quantitative real-time PCR (qRT-PCR), and Western blot (WB) to obtain the results. Results: Ngb and Hif-1α were significantly (P<0.05) expressed in the cerebellar cortex, piriform lobe, medulla, and corpus callosum of the adult yak while in the young yak brain tissues, the protein expressions were significantly found in the white matter of the cerebellum, pineal gland, corpus callosum, and cerebellar cortex. The Ngb and Hif-1α expression showed similarities and differences. This may have resulted from similar animal species, source of nutrition, age factors, brain size, emotional activities, and communication. The findings documented that Ngb and Hif-1α are commonly expressed in various adult and young yak brain tissues. Multiple roles in the brain tissues of the adult and young yaks are involved in the expression and distribution and are proposed to play a significant role in the adaptation of the yak to the high altitude environment. Conclusion: This study provides meaningful data to understand the adaptive mechanism to hypoxia and recommended researchers to expand on the adaptive mechanism and brain tissues that are not recorded.

Contexto: O cérebro é um órgão que funciona como o centro do sistema nervoso em todos os animais vertebrados e na maioria dos invertebrados. Objetivo: O estudo examinou a expressão de neuroglobina (Ngb) e fator-1α indutível por hipóxia (Hif-1α) em tecidos cerebrais de iaques adultos e jovens e forneceu aos pesquisadores uma visão significativa da anatomia, fisiologia e bioquímica desse mamífero. Método: O estudo utilizou imuno-histoquímica (IHC), PCR quantitativo em tempo real (qRT-PCR) e western blot (WB) para a obtenção dos resultados. Resultados: Ngb e Hif-1α foram significativamente (P < 0,05) expressos no córtex cerebelar, lobo piriforme, medula e corpo caloso do iaque adulto, enquanto nos tecidos cerebrais do iaque jovem as expressões proteicas foram encontradas significativamente na substância branca do cerebelo, glândula pineal, corpo caloso e córtex cerebelar. A expressão de Ngb e Hif-1α apresentou semelhanças e diferenças. Isso pode ter resultado de espécies animais semelhantes, fonte de nutrição, fatores de idade, tamanho do cérebro, atividades emocionais e comunicação. Os resultados documentaram que o Ngb e o Hif-1α são comumente expressos em vários tecidos cerebrais de iaques adultos e jovens. Múltiplos papéis nos tecidos cerebrais de iaques adultos e jovens estão envolvidos na expressão e distribuição e são propostos para desempenhar um papel significativo na adaptação do iaque ao ambiente de alta altitude. Conclusão: Este estudo fornece dados significativos para compreender o mecanismo adaptativo à hipóxia e recomendou que os pesquisadores expandissem o mecanismo adaptativo e os tecidos cerebrais que não foram registrados.

Comparative study on the distribution and expression of Neuroglobin and Hypoxia-inducible factor-1α in the telencephalon of yak and cattle / Estudo comparativo da distribuição e expressão de fator-1α indutível por neuroglobina e hipóxia no telencéfalo de iaques e bovinos

The telencephalon refers to the most highly developed and anterior part of the forebrain, consisting mainly of the cerebral hemispheres. The study determined Neuroglobin (Ngb) and Hypoxia-inducible factor (HIF-1α) expression in the telencephalon of yak and cattle, and compare the expression and distribution pattern of Ngb and HIF-1α in the two animals. Immunohistochemistry (IHC), quantitative real-time Polymerase Chain Reaction (qRT-PCR), and Western blot (WB) were employed to investigate Ngb and Hif-1α expression in the telencephalon of yak and cattle. mRNA and protein expressions of Ngb and HIF-1α showed positive in different tissues of the yak and cattle telencephalon. Ngb expression in tissues of the yak recorded higher as compare to cattle while HIF-1α expression was found higher in cattle than yak. The HIF-1α expression in some tissues of yak telencephalon was consistent with the cattle. The results documented that HIF-1α may have a direct or indirect synergistic effect on Ngb expression in the yak telencephalon to improve hypoxia adaptation. It is suggested that yak may need more Ngb expression for adaptation, but the expression of HIF-1α seems to be down-regulated during long-term adaptation, and the specific causes of this phenomenon needs to be further verified.

O telencéfalo refere-se à parte anterior e mais desenvolvida do prosencéfalo, consistindo principalmente dos hemisférios cerebrais. O estudo determinou a expressão de neuroglobina (Ngb) e fator indutível por hipóxia (HIF-1α) no telencéfalo de iaques e bovinos e comparou a expressão e o padrão de distribuição de Ngb e HIF-1α nos dois animais. Imuno-histoquímica (IHC), reação em cadeia da polimerase quantitativa em tempo real (qRT-PCR) e Western blot (WB) foram empregados para investigar a expressão de Ngb e Hif-1α no telencéfalo de iaques e bovinos. As expressões de mRNA e proteínas de Ngb e HIF-1α mostraram-se positivas em diferentes tecidos do telencéfalo de iaque e bovino. A expressão de Ngb nos tecidos do iaque foi registrada mais alta em comparação com o gado, enquanto a expressão do HIF-1α foi encontrada mais alta no gado do que no iaque. A expressão de HIF-1α em alguns tecidos do telencéfalo de iaque foi consistente com o gado. Os resultados documentaram que o HIF-1α pode ter um efeito sinérgico direto ou indireto na expressão de Ngb no telencéfalo de iaque para melhorar a adaptação à hipóxia. É sugerido que o iaque pode precisar de mais expressão de Ngb para adaptação, mas a expressão de HIF-1α parece ser regulada para baixo durante a adaptação de longo prazo, e as causas específicas desse fenômeno precisam ser verificadas.

Comparative study on the distribution and expression of Neuroglobin and Hypoxia-inducible factor-1α in the telencephalon of yak and cattle / Estudo comparativo da distribuição e expressão de fator-1 indutível por neuroglobina e hipóxia no telencéfalo de iaques e bovinos

Abstract The telencephalon refers to the most highly developed and anterior part of the forebrain, consisting mainly of the cerebral hemispheres. The study determined Neuroglobin (Ngb) and Hypoxia-inducible factor (HIF-1α) expression in the telencephalon of yak and cattle, and compare the expression and distribution pattern of Ngb and HIF-1α in the two animals. Immunohistochemistry (IHC), quantitative real-time Polymerase Chain Reaction (qRT-PCR), and Western blot (WB) were employed to investigate Ngb and Hif-1α expression in the telencephalon of yak and cattle. mRNA and protein expressions of Ngb and HIF-1α showed positive in different tissues of the yak and cattle telencephalon. Ngb expression in tissues of the yak recorded higher as compare to cattle while HIF-1α expression was found higher in cattle than yak. The HIF-1α expression in some tissues of yak telencephalon was consistent with the cattle. The results documented that HIF-1α may have a direct or indirect synergistic effect on Ngb expression in the yak telencephalon to improve hypoxia adaptation. It is suggested that yak may need more Ngb expression for adaptation, but the expression of HIF-1α seems to be down-regulated during long-term adaptation, and the specific causes of this phenomenon needs to be further verified.

Resumo O telencéfalo refere-se à parte anterior e mais desenvolvida do prosencéfalo, consistindo principalmente dos hemisférios cerebrais. O estudo determinou a expressão de neuroglobina (Ngb) e fator indutível por hipóxia (HIF-1α) no telencéfalo de iaques e bovinos e comparou a expressão e o padrão de distribuição de Ngb e HIF-1α nos dois animais. Imuno-histoquímica (IHC), reação em cadeia da polimerase quantitativa em tempo real (qRT-PCR) e Western blot (WB) foram empregados para investigar a expressão de Ngb e Hif-1α no telencéfalo de iaques e bovinos. As expressões de mRNA e proteínas de Ngb e HIF-1α mostraram-se positivas em diferentes tecidos do telencéfalo de iaque e bovino. A expressão de Ngb nos tecidos do iaque foi registrada mais alta em comparação com o gado, enquanto a expressão do HIF-1α foi encontrada mais alta no gado do que no iaque. A expressão de HIF-1α em alguns tecidos do telencéfalo de iaque foi consistente com o gado. Os resultados documentaram que o HIF-1α pode ter um efeito sinérgico direto ou indireto na expressão de Ngb no telencéfalo de iaque para melhorar a adaptação à hipóxia. É sugerido que o iaque pode precisar de mais expressão de Ngb para adaptação, mas a expressão de HIF-1α parece ser regulada para baixo durante a adaptação de longo prazo, e as causas específicas desse fenômeno precisam ser verificadas.

Comparative study of the distribution and expression of Neuroglobin and Hypoxia-inducible factor-1α in the adult and young Yak Brain / Estudo comparativo da distribuição e expressão de neuroglobina e fator-1α indutível por hipóxia em adultos e jovens iaques (Yak Brain)

Abstract Background The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. Aim The study examined the expression of Neuroglobin (Ngb) and Hypoxia-inducible factor-1α (Hif-1α) in adult and young yak brain tissues, and provided researchers with meaningful insight into the anatomy, physiology, and biochemistry of this mammal. Method The study employed immunohistochemistry (IHC), quantitative real-time PCR (qRT-PCR), and Western blot (WB) to obtain the results. Results Ngb and Hif-1α were significantly (P<0.05) expressed in the cerebellar cortex, piriform lobe, medulla, and corpus callosum of the adult yak while in the young yak brain tissues, the protein expressions were significantly found in the white matter of the cerebellum, pineal gland, corpus callosum, and cerebellar cortex. The Ngb and Hif-1α expression showed similarities and differences. This may have resulted from similar animal species, source of nutrition, age factors, brain size, emotional activities, and communication. The findings documented that Ngb and Hif-1α are commonly expressed in various adult and young yak brain tissues. Multiple roles in the brain tissues of the adult and young yaks are involved in the expression and distribution and are proposed to play a significant role in the adaptation of the yak to the high altitude environment. Conclusion This study provides meaningful data to understand the adaptive mechanism to hypoxia and recommended researchers to expand on the adaptive mechanism and brain tissues that are not recorded.

Resumo Contexto O cérebro é um órgão que funciona como o centro do sistema nervoso em todos os animais vertebrados e na maioria dos invertebrados. Objetivo O estudo examinou a expressão de neuroglobina (Ngb) e fator-1α indutível por hipóxia (Hif-1α) em tecidos cerebrais de iaques adultos e jovens e forneceu aos pesquisadores uma visão significativa da anatomia, fisiologia e bioquímica desse mamífero. Método O estudo utilizou imuno-histoquímica (IHC), PCR quantitativo em tempo real (qRT-PCR) e western blot (WB) para a obtenção dos resultados. Resultados Ngb e Hif-1α foram significativamente (P < 0,05) expressos no córtex cerebelar, lobo piriforme, medula e corpo caloso do iaque adulto, enquanto nos tecidos cerebrais do iaque jovem as expressões proteicas foram encontradas significativamente na substância branca do cerebelo, glândula pineal, corpo caloso e córtex cerebelar. A expressão de Ngb e Hif-1α apresentou semelhanças e diferenças. Isso pode ter resultado de espécies animais semelhantes, fonte de nutrição, fatores de idade, tamanho do cérebro, atividades emocionais e comunicação. Os resultados documentaram que o Ngb e o Hif-1α são comumente expressos em vários tecidos cerebrais de iaques adultos e jovens. Múltiplos papéis nos tecidos cerebrais de iaques adultos e jovens estão envolvidos na expressão e distribuição e são propostos para desempenhar um papel significativo na adaptação do iaque ao ambiente de alta altitude. Conclusão Este estudo fornece dados significativos para compreender o mecanismo adaptativo à hipóxia e recomendou que os pesquisadores expandissem o mecanismo adaptativo e os tecidos cerebrais que não foram registrados.

Clinical value of serum neuroglobin in evaluating hypoglycemic brain injury in neonates / 中国当代儿科杂志

OBJECTIVE@#To study the clinical value of serum neuroglobin in evaluating hypoglycemic brain injury in neonates.@*METHODS@#A total of 100 neonates with hypoglycemia were enrolled as subjects. According to amplitude-integrated EEG (aEEG) findings and/or clinical manifestations, they were divided into symptomatic hypoglycemic brain injury group (n=22), asymptomatic hypoglycemic brain injury group (n=37) and hypoglycemic non-brain injury group (n=41). The three groups were compared in terms of blood glucose, duration of hypoglycemia, levels of neuroglobin and neuron-specific enolase (NSE), and modified aEEG score. The correlation of neuroglobin with NSE and modified aEEG score was analyzed. The receiver operating characteristic (ROC) curve was plotted.@*RESULTS@#Compared with the asymptomatic hypoglycemic brain injury and hypoglycemic non-brain injury groups, the symptomatic hypoglycemic brain injury group had significantly lower blood glucose and modified aEEG score, significantly higher neuroglobin and NSE levels, and a significantly longer duration of hypoglycemia (P<0.05). Compared with the hypoglycemic non-brain injury group, the asymptomatic hypoglycemic brain injury group had significantly lower blood glucose and modified aEEG score, significantly higher neuroglobin and NSE levels, and a significantly longer duration of hypoglycemia (P<0.05). Neuroglobin was positively correlated with NSE and duration of hypoglycemia (r=0.922 and 0.929 respectively; P<0.05) and negatively correlated with blood glucose and modified aEEG score (r=-0.849 and -0.968 respectively; P<0.05). The areas under the ROC curve of neuroglobin, NSE and modified aEEG score were 0.894, 0.890 and 0.941 respectively, and neuroglobin had a sensitivity of 80.8% and a specificity of 95.8% at the optimal cut-off value of 108 mg/L.@*CONCLUSIONS@#Like NSE and modified aEEG score, serum neuroglobin can also be used as a specific indicator for the assessment of brain injury in neonates with hypoglycemia and has a certain value in clinical practice.