Identification and characterization of isocitrate dehydrogenase 1 (IDH1) as a functional target of marine natural product grincamycin B.

Grincamycins (GCNs) are a class of angucycline glycosides isolated from actinomycete Streptomyces strains that have potent antitumor activities, but their antitumor mechanisms remain unknown. In this study, we tried to identify the cellular target of grincamycin B (GCN B), one of most dominant and active secondary metabolites, using a combined strategy. We showed that GCN B-selective-induced apoptosis of human acute promyelocytic leukemia (APL) cell line NB4 through increase of ER stress and intracellular reactive oxygen species (ROS) accumulation. Using a strategy of combining phenotype, transcriptomics and protein microarray approaches, we identified that isocitrate dehydrogenase 1(IDH1) was the putative target of GCN B, and confirmed that GCNs were a subset of selective inhibitors targeting both wild-type and mutant IDH1 in vitro. It is well-known that IDH1 converts isocitrate to 2-oxoglutarate (2-OG), maintaining intracellular 2-OG homeostasis. IDH1 and its mutant as the target of GCN B were validated in NB4 cells and zebrafish model. Knockdown of IDH1 in NB4 cells caused the similar phenotype as GCN B treatment, and supplementation of N-acetylcysteine partially rescued the apoptosis caused by IDH1 interference in NB4 cells. In zebrafish model, GCN B effectively restored myeloid abnormality caused by overexpression of mutant IDH1(R132C). Taken together, we demonstrate that IDH1 is one of the antitumor targets of GCNs, suggesting wild-type IDH1 may be a potential target for hematological malignancies intervention in the future.

NG2-glia cell proliferation and differentiation by glial growth factor 2 (GGF2), a strategy to promote functional recovery after ischemic stroke.

Stroke is the leading cause of adult disability. Spontaneous functional recovery occurs after ischemic stroke, but it is very limited. Therefore, it is urgent to find a strategy to promote functional recovery after stroke in clinical setting. Gray matter damage has received extensive attention owing to the important roles of the gray matter in synaptic plasticity, cognitive, and motor function. However, stroke also causes white matter damage, which accounts for half of the infarct volume and can be aggravated by blood brain barrier damage. Disruption of white matter integrity, which is characterized by death of oligodendrocytes (OLs), loss of myelin, and axonal injury, greatly contributes to impaired neurological function. Impaired proliferation and differentiation of OL precursor cell (OPC, NG2-glia cells) play an important role in limited functional recovery after ischemic stroke and inhibitor of differentiation 2 (ID2) is a key factor controlling NG2-glia cells differentiation. It has been reported that the number of NG2-glia cells in the peri-infarction area significantly increases after ischemic stroke and glial growth factor (GGF2) administration promotes the proliferation and differentiation of NG2-glia cells as well as functional recovery after spinal cord injury. On the basis of the important roles of GGF2 in functional recovery and those of ID2 in NG2-glia cell proliferation and differentiation, we propose that after binding with the ErBb receptor on the surface of NG2-glia cells, GGF2 promotes NG2-glia cell proliferation and differentiation, thereby repairing BBB and white matter integrity and promoting neural functional recovery after ischemic stroke.

Inhibition of Reactive Astrocytes with Fluorocitrate Ameliorates Learning and Memory Impairment Through Upregulating CRTC1 and Synaptophysin in Ischemic Stroke Rats.

Ischemic stroke often causes motor and cognitive deficits. Deregulated glia gap junction communication, which is reflected by increased protein levels of glial fibrillary acidic protein (GFAP) and connexin 43 (Cx43), has been observed in ischemic hippocampus and has been associated with cognitive impairment in animal stroke models. Here, we tested the hypothesis that reactive astrocytes-mediated loss of synaptophysin (SYP) and CREB-regulated transcription coactivator 1 (CRTC1) contribute to dysfunction in glia gap junction communication and memory impairment after ischemic stroke. Male Sprague-Dawley rats were subjected to a 90-min middle cerebral artery occlusion (MCAO) with 7-day reperfusion. Fluorocitrate (1 nmol), the reversible inhibitor of the astrocytic tricarboxylic acid cycle, was injected into the right lateral ventricle of MCAO rats once every 2 days starting immediately before reperfusion. The Morris water maze was used to assess memory in conjunction with western blotting and immunostaining to detect protein expression and distribution in the hippocampus. Our results showed that ischemic stroke caused significant memory impairment accompanied by increased protein levels of GFAP and Cx43 in hippocampal tissue. In addition, the levels of several key memory-related important proteins including SYP, CRTC1, myelin basic protein and high-mobility group-box-1 were significantly reduced in the hippocampal tissue. Of note, inhibition of reactive astrocytes with fluorocitrate was shown to significantly reverse the above noted changes induced by ischemic stroke. Taken together, our findings demonstrate that inhibiting reactive astrocytes with fluorocitrate immediately before reperfusion may protect against ischemic stroke-induced memory impairment through the upregulation of CRTC1 and SYP.

Study on correlation of thyroid hormone level, lipid and glucose metabolism and blood uric acid in patients with hyperthyroidism / 国际检验医学杂志

Objective To explore the correlation of thyroid hormone level, blood glucose level, blood lipid level and blood uric acid in patients with hyperthyroidism.Methods Totally 87patients with hyperthyroidism who were treated in our hospital from June 2015to December 2017were selected as the observation group, the other 69healthy people in the same period were selected as the control group.The fasting blood glucose (FBG), total cholesterol (TC), three glycerol (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), free three triiodothyronine (FT3), free thyroxine (FT4), thyroid stimulating hormone (TSH) and blood uric acid level were compared, and the correlation among the above indicators were analyzed.Results The levels of FBG, FT3, FT4and blood uric acid before treatment in the observation group were higher than those of the control group, and the levels of TSH, TC, TG, HDL-C and LDL-C were lower than those of the control group, the differences were statistically significant (P＜0.05).After treatment, the levels of FBG, FT3, FT4and blood uric acid were significantly decreased in the observation group, while the levels of TSH, TC, TG, HDL-C and LDL-C increased significantly, the differences were statistically significant between before and after treatment (P＜0.05).The levels of FT3and FT4were positively correlated with blood uric acid and FBG level in hyperthyroidism patients, and negatively correlated with the levels of TC, TG, HDL-C and LDL-C.The level of TSH was positively correlated with the levels of TC, TG, HDL-C and LDL-C, and had a negative correlation with the levels of FBG and blood uric acid.Conclusion The thyroid hormone level is closely related to lipid and glucose metabolism and blood uric acid level in hyperthyroidism patients.When the thyroid hormone is corrected, the blood glucose and blood lipid indexes turn to normal.It suggests that the clinical treatment of hyperthyroidism should be taken as the main means to correct the abnormal thyroid hormone.

Corrigendum: ß2-Adrenergic Receptor-Mediated HIF-1α Upregulation Mediates Blood Brain Barrier Damage in Acute Cerebral Ischemia.

[This corrects the article on p. 257 in vol. 10, PMID: 28855859.].

ß2-Adrenergic Receptor-Mediated HIF-1α Upregulation Mediates Blood Brain Barrier Damage in Acute Cerebral Ischemia.

Disruption of the blood brain barrier (BBB) within the thrombolytic time window is an antecedent event to intracerebral hemorrhage in ischemic stroke. Our recent studies showed that 2-h cerebral ischemia induced BBB damage in non-infarcted area and secreted matrix metalloproteinase-2 (MMP-2) accounted for this disruption. However, the factors that affect MMP-2 secretion and regulate BBB damage remains unknown. Since hypoxia-inducible factor-1 alpha (HIF-1α) was discovered as a mater regulator in hypoxia, we sought to investigate the roles of HIF-1α in BBB damage as well as the factors regulating HIF-1α expression in the ischemic brain. in vivo rat middle cerebral artery occlusion (MCAO) and in vitro oxygen glucose deprivation (OGD) models were used to mimic ischemia. Pretreatment with HIF-1α inhibitor YC-1 significantly inhibited 2-h MCAO-induced BBB damage, which was accompanied by suppressed occludin degradation and vascular endothelial growth factor (VEGF) mRNA upregulation. Interestingly, ß2-adrenergic receptor (ß2-AR) antagonist ICI 118551 attenuated ischemia-induced BBB damage by regulating HIF-1α expression. Double immunostaining showed that HIF-1α was upregulated in ischemic neurons but not in astrocytes andendothelial cells. Of note, HIF-1α inhibition with inhibitor YC-1 or siRNA significantly prevented OGD-induced VEGF upregulation as well as the secretion of VEGF and MMP-2 in neurons. More importantly, blocking ß2-AR with ICI 118551 suppressedHIF-1α upregulation in ischemic neurons and attenuated occludin degradation induced by the conditioned media of OGD-treatedneurons. Taken together, blockade of ß2-AR-mediated HIF-1α upregulation mediates BBB damage during acute cerebral ischemia. These findings provide new mechanistic understanding of early BBB damage in ischemic stroke and may help reduce thrombolysis-related hemorrhagic complications.

Melatonin Supplementation, a Strategy to Prevent Neurological Diseases through Maintaining Integrity of Blood Brain Barrier in Old People.

Blood brain barrier (BBB) plays a crucial role in maintaining homeostasis of microenvironment that is essential to neural function of the central nervous system (CNS). When facing various extrinsic or intrinsic stimuli, BBB is damaged which is an early event in pathogenesis of a variety of neurological diseases in old patients including acute and chronic cerebral ischemia, Alzheimer's disease and etc. Treatments that could maintain the integrity of BBB may prevent neurological diseases following various stimuli. Old people often face a common stress of sepsis, during which lipopolysaccharide (LPS) is released into circulation and the integrity of BBB is damaged. Of note, there is a significant decrease of melatonin level in old people and animal. Melatonin has been shown to preserves BBB integrity and permeability via a variety of pathways: inhibition of matrix metalloproteinase-9 (MMP-9), inhibition of NADPH oxidase-2, and impact on silent information regulator 1 (SIRT1) and nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome. More important, a recent study showed that melatonin supplementation alleviates LPS-induced BBB damage in old mice through activating AMP-activated protein kinase (AMPK) and inhibiting gp91phox, suggesting that melatonin supplementation may help prevent neurological diseases through maintaining the integrity of BBB in old people.

Melatonin alleviates lipopolysaccharide-compromised integrity of blood-brain barrier through activating AMP-activated protein kinase in old mice.

Blood-brain barrier (BBB) dysfunction is considered to be an early event in the pathogenesis of a variety of neurological diseases in old patients, and this could occur in old people even when facing common stress. However, the mechanism remains to be defined. In this study, we tested the hypothesis that decreased melatonin levels may account for the BBB disruption in old mice challenged with lipopolysaccharide (LPS), which mimicked the common stress of sepsis. Mice (24-28 months of age) received melatonin (10 mg kg-1  day-1 , intraperitoneally, i.p.) or saline for one week before exposing to LPS (1 mg kg-1 , i.p.). Evan's blue dye (EB) and immunoglobulin G (IgG) leakage were used to assess BBB permeability. Immunostaining and Western blot were used to detect protein expression and distribution. Our results showed that LPS significantly increased BBB permeability in old mice accompanied by the degradation of tight junction proteins occludin and claudin-5, suppressed AMP-activated protein kinase (AMPK) activation, and elevated gp91phox protein expression. Interestingly, administration of melatonin for one week significantly decreased LPS-induced BBB disruption, AMPK suppression, and gp91phox upregualtion. Moreover, activation of AMPK with metformin significantly inhibited LPS-induced gp91phox upregualtion in endothelial cells. Taken together, our findings demonstrate that melatonin alleviates LPS-induced BBB disruption through activating AMPK and inhibiting gp91phox upregulation in old mice.

Normobaric Hyperoxia Extends Neuro- and Vaso-Protection of N-Acetylcysteine in Transient Focal Ischemia.

N-acetylcysteine (NAC), a precursor of glutathione that reduces reperfusion-induced injury, has been shown protection when it was administered pre-ischemia. However, less is known about the effect when it was given post-ischemia and there is no positive result associated with anti-oxidant in clinical trials. This study investigated the neuro- and vaso-protection of post-ischemia NAC administration as well as combining NAC with normobaric hyperoxia (NBO). Male Sprague-Dawley rats were exposed to NBO or normoxia during 2-h occlusion of the middle cerebral artery, followed by 48-h reperfusion. NAC or vehicle was intraperitoneally administered to rats immediately before reperfusion onset. NAC and NBO treatments produced 1.2 and 30 % reduction of infarction volume, respectively, and combination treatment showed greater reduction (59.8 %) as well as more decrease of hemispheric swelling volume. Of note, combination therapy showed improved neurological assessment and motor function which were sustained for 7 days after reperfusion. We also determined that the combination therapy showed greater inhibitory effects on tight junction protein degradation accompanied by Evan's blue extravasation, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) induction, and poly ADP-ribose polymerase (PARP)-1 activation in ischemic brain tissue. Our results showed that although post-ischemia NAC administration had limited protection, combination treatment of NAC plus NBO effectively prevented blood-brain barrier (BBB) damage and significantly improved the outcome of brain injury, providing new evidence to support the concept that "cocktail" treatment targeting different stages provides better neuro- and vaso-protection than current individual treatment that has all failed in their clinical trials.

Oxygen or cooling, to make a decision after acute ischemia stroke.

The presence of a salvageable penumbra, a region of ischemic brain tissue with sufficient energy for short-term survival, has been widely agreed as the premise for thrombolytic therapy with tissue plasminogen activator (tPA), which remains the only United States Food and Drug Administration (FDA) approved treatment for acute ischemia stroke. However, the use of tPA has been profoundly constrained due to its narrow therapeutic time window and the increased risk of potentially deadly hemorrhagic transformation (HT). Blood brain barrier (BBB) damage within the thrombolytic time window is an indicator for tPA-induced HT and both normobaric hyperoxia (NBO) and hypothermia have been shown to protect the BBB from ischemia/reperfusion injury. Therefore, providing the O2 as soon as possible (NBO treatment), freezing the brain (hypothermia treatment) to slow down ischemia-induced BBB damage or their combined use may extend the time window for the treatment of tPA. In this review, we summarize the protective effects of NBO, hypothermia or their use combined with tPA on ischemia stroke, based on which, the combination of NBO and hypothermia may be an ideal early stroke treatment to preserve the ischemic penumbra. Given this, there is an urge for large randomized controlled trials to address the effect.