Overexpression of long noncoding RNA DUXAP8 inhibits ER-phagy through activating AKT/mTOR signaling and contributes to preeclampsia.

Preeclampsia (PE) is a life-threatening pregnancy-specific complication with controversial mechanisms and no effective treatment except delivery is available. Currently, increasing researchers suggested that PE shares pathophysiologic features with protein misfolding/aggregation disorders, such as Alzheimer disease (AD). Evidences have proposed defective autophagy as a potential source of protein aggregation in PE. Endoplasmic reticulum-selective autophagy (ER-phagy) plays a critical role in clearing misfolded proteins and maintaining ER homeostasis. However, its roles in the molecular pathology of PE remain unclear. We found that lncRNA DUXAP8 was upregulated in preeclamptic placentae and significantly correlated with clinical indicators. DUXAP8 specifically binds to PCBP2 and inhibits its ubiquitination-mediated degradation, and decreased levels of PCBP2 reversed the activation effect of DUXAP8 overexpression on AKT/mTOR signaling pathway. Function experiments showed that DUXAP8 overexpression inhibited trophoblastic proliferation, migration, and invasion of HTR-8/SVneo and JAR cells. Moreover, pathological accumulation of swollen and lytic ER (endoplasmic reticulum) was observed in DUXAP8-overexpressed HTR8/SVneo cells and PE placental villus trophoblast cells, which suggesting that ER clearance ability is impaired. Further studies found that DUXAP8 overexpression impaired ER-phagy and caused protein aggregation medicated by reduced FAM134B and LC3II expression (key proteins involved in ER-phagy) via activating AKT/mTOR signaling pathway. The increased level of FAM134B significantly reversed the inhibitory effect of DUXAP8 overexpression on the proliferation, migration, and invasion of trophoblasts. In vivo, DUXAP8 overexpression through tail vein injection of adenovirus induced PE-like phenotypes in pregnant rats accompanied with activated AKT/mTOR signaling, decreased expression of FAM134B and LC3-II proteins and increased protein aggregation in placental tissues. Our study reveals the important role of lncRNA DUXAP8 in regulating trophoblast biological behaviors through FAM134B-mediated ER-phagy, providing a new theoretical basis for understanding the pathogenesis of PE.

Isoflurane provides neuroprotection in neonatal hypoxic ischemic brain injury by suppressing apoptosis / Isoflurano fornece neuroproteção em lesão cerebral hipóxico-isquêmica neonatal por inibição da apoptose

Abstract Background and objectives: Isoflurane is halogenated volatile ether used for inhalational anesthesia. It is widely used in clinics as an inhalational anesthetic. Neonatal hypoxic ischemia injury ensues in the immature brain that results in delayed cell death via excitotoxicity and oxidative stress. Isoflurane has shown neuroprotective properties that make a beneficial basis of using isoflurane in both cell culture and animal models, including various models of brain injury. We aimed to determine the neuroprotective effect of isoflurane on hypoxic brain injury and elucidated the underlying mechanism. Methods: A hippocampal slice, in artificial cerebrospinal fluid with glucose and oxygen deprivation, was used as an in vitro model for brain hypoxia. The orthodromic population spike and hypoxic injury potential were recorded in the CA1 and CA3 regions. Amino acid neurotransmitters concentration in perfusion solution of hippocampal slices was measured. Results: Isoflurane treatment caused delayed elimination of population spike and improved the recovery of population spike; decreased frequency of hypoxic injury potential, postponed the onset of hypoxic injury potential and increased the duration of hypoxic injury potential. Isoflurane treatment also decreased the hypoxia-induced release of amino acid neurotransmitters such as aspartate, glutamate and glycine induced by hypoxia, but the levels of γ-aminobutyric acid were elevated. Morphological studies showed that isoflurane treatment attenuated edema of pyramid neurons in the CA1 region. It also reduced apoptosis as evident by lowered expression of caspase-3 and PARP genes. Conclusions: Isoflurane showed a neuro-protective effect on hippocampal neuron injury induced by hypoxia through suppression of apoptosis.

Resumo Justificativa e objetivos: Isoflurano é um éter volátil halogenado usado para anestesia por via inalatória. É amplamente usado na clínica como um anestésico para inalação. A lesão hipóxico-isquêmica neonatal ocorre no cérebro imaturo e resulta em morte celular tardia via excitotoxicidade e estresse oxidativo. Isoflurano mostrou ter propriedades neuroprotetoras que formam uma base benéfica para o seu uso tanto em cultura de células quanto em modelos animais, incluindo vários modelos de lesão cerebral. Nosso objetivo foi determinar o efeito neuroprotetor de isoflurano em hipóxia cerebral e elucidar o mecanismo subjacente. Métodos: Fatias de hipocampo, em fluido cerebrospinal artificial (CSFA) com glicose e privação de oxigênio, foram usadas como um modelo in vitro de hipóxia cerebral. O pico de população ortodrômica (PPO) e o potencial de lesão hipóxica (PLH) foram registrados nas regiões CA1 e CA3. A concentração de neurotransmissores de aminoácidos na solução de perfusão das fatias de hipocampo foi medida. Resultados: O tratamento com isoflurano retardou a eliminação do PPO e melhorou a recuperação do PPO; diminuiu a frequência do PLH, retardou o início do PLH e aumentou a duração do PLH. O tratamento com isoflurano também diminuiu a liberação de neurotransmissores de aminoácidos induzida pela hipóxia, como aspartato, glutamato e glicina, mas os níveis de ácido γ-aminobutírico (GABA) estavam elevados. Estudos morfológicos mostram que o tratamento de edema com isoflurano atenuou o edema de neurônios piramidais na região CA1. Também reduziu a apoptose, como mostrado pela expressão reduzida da caspase-3 e genes PARP. Conclusões: Isoflurano mostrou um efeito neuroprotetor na lesão neuronal no hipocampo induzida por hipóxia através da supressão de apoptose.

Isoflurane provides neuroprotection in neonatal hypoxic ischemic brain injury by suppressing apoptosis.

BACKGROUND AND OBJECTIVES: Isoflurane is halogenated volatile ether used for inhalational anesthesia. It is widely used in clinics as an inhalational anesthetic. Neonatal hypoxic ischemia injury ensues in the immature brain that results in delayed cell death via excitotoxicity and oxidative stress. Isoflurane has shown neuroprotective properties that make a beneficial basis of using isoflurane in both cell culture and animal models, including various models of brain injury. We aimed to determine the neuroprotective effect of isoflurane on hypoxic brain injury and elucidated the underlying mechanism. METHODS: A hippocampal slice, in artificial cerebrospinal fluid with glucose and oxygen deprivation, was used as an in vitro model for brain hypoxia. The orthodromic population spike and hypoxic injury potential were recorded in the CA1 and CA3 regions. Amino acid neurotransmitters concentration in perfusion solution of hippocampal slices was measured. RESULTS: Isoflurane treatment caused delayed elimination of population spike and improved the recovery of population spike; decreased frequency of hypoxic injury potential, postponed the onset of hypoxic injury potential and increased the duration of hypoxic injury potential. Isoflurane treatment also decreased the hypoxia-induced release of amino acid neurotransmitters such as aspartate, glutamate and glycine induced by hypoxia, but the levels of γ-aminobutyric acid were elevated. Morphological studies showed that isoflurane treatment attenuated edema of pyramid neurons in the CA1 region. It also reduced apoptosis as evident by lowered expression of caspase-3 and PARP genes. CONCLUSIONS: Isoflurane showed a neuro-protective effect on hippocampal neuron injury induced by hypoxia through suppression of apoptosis.

[Isoflurane provides neuroprotection in neonatal hypoxic ischemic brain injury by suppressing apoptosis]. / Isoflurano fornece neuroproteção em lesão cerebral hipóxico­isquêmica neonatal por inibição da apoptose.

BACKGROUND AND OBJECTIVES: Isoflurane is halogenated volatile ether used for inhalational anesthesia. It is widely used in clinics as an inhalational anesthetic. Neonatal hypoxic ischemia injury ensues in the immature brain that results in delayed cell death via excitotoxicity and oxidative stress. Isoflurane has shown neuroprotective properties that make a beneficial basis of using isoflurane in both cell culture and animal models, including various models of brain injury. We aimed to determine the neuroprotective effect of isoflurane on hypoxic brain injury and elucidated the underlying mechanism. METHODS: A hippocampal slice, in artificial cerebrospinal fluid with glucose and oxygen deprivation, was used as an in vitro model for brain hypoxia. The orthodromic population spike and hypoxic injury potential were recorded in the CA1 and CA3 regions. Amino acid neurotransmitters concentration in perfusion solution of hippocampal slices was measured. RESULTS: Isoflurane treatment caused delayed elimination of population spike and improved the recovery of population spike; decreased frequency of hypoxic injury potential, postponed the onset of hypoxic injury potential and increased the duration of hypoxic injury potential. Isoflurane treatment also decreased the hypoxia-induced release of amino acid neurotransmitters such as aspartate, glutamate and glycine induced by hypoxia, but the levels of γ-aminobutyric acid were elevated. Morphological studies showed that isoflurane treatment attenuated edema of pyramid neurons in the CA1 region. It also reduced apoptosis as evident by lowered expression of caspase-3 and PARP genes. CONCLUSIONS: Isoflurane showed a neuro-protective effect on hippocampal neuron injury induced by hypoxia through suppression of apoptosis.