Nannan Lu

All Publications

• PTER is a N-acetyltaurine hydrolase that regulates feeding and obesity. Nature Wei, W., Lyu, X., Markhard, A. L., Fu, S., Mardjuki, R. E., Cavanagh, P. E., Zeng, X., Rajniak, J., Lu, N., Xiao, S., Zhao, M., Moya-Garzon, M. D., Truong, S. D., Chou, J. C., Wat, L. W., Chidambaranathan-Reghupaty, S., Coassolo, L., Xu, D., Shen, F., Huang, W., Ramirez, C. B., Jang, C., Li, L., Svensson, K. J., Fischbach, M. A., Long, J. Z. 2024

  Abstract

  Taurine is a conditionally essential micronutrient and one of the most abundant amino acids in humans1-3. In endogenous taurine metabolism, dedicated enzymes are involved in the biosynthesis of taurine from cysteine and in the downstream metabolism of secondary taurine metabolites4,5. One taurine metabolite is N-acetyltaurine6. Levels of N-acetyltaurine are dynamically regulated by stimuli that alter taurine or acetate flux, including endurance exercise7, dietary taurine supplementation8 and alcohol consumption6,9. So far, the identities of the enzymes involved in N-acetyltaurine metabolism, and the potential functions of N-acetyltaurine itself, have remained unknown. Here we show that the body mass index associated orphan enzyme phosphotriesterase-related (PTER)10 is a physiological N-acetyltaurine hydrolase. In vitro, PTER catalyses the hydrolysis of N-acetyltaurine to taurine and acetate. In mice, PTER is expressed in the kidney, liver and brainstem. Genetic ablation of Pter in mice results in complete loss of tissue N-acetyltaurine hydrolysis activity and a systemic increase in N-acetyltaurine levels. After stimuli that increase taurine levels, Pter knockout mice exhibit reduced food intake, resistance to diet-induced obesity and improved glucose homeostasis. Administration of N-acetyltaurine to obese wild-type mice also reduces food intake and body weight in a GFRAL-dependent manner. These data place PTER into a central enzymatic node of secondary taurine metabolism and uncover a role for PTER and N-acetyltaurine in body weight control and energy balance.

  View details for DOI 10.1038/s41586-024-07801-6

  View details for PubMedID 39112712

  View details for PubMedCentralID 3501277

• Atlas of the aging mouse brain reveals white matter as vulnerable foci. Cell Hahn, O., Foltz, A. G., Atkins, M., Kedir, B., Moran-Losada, P., Guldner, I. H., Munson, C., Kern, F., Pálovics, R., Lu, N., Zhang, H., Kaur, A., Hull, J., Huguenard, J. R., Grönke, S., Lehallier, B., Partridge, L., Keller, A., Wyss-Coray, T. 2023

  Abstract

  Aging is the key risk factor for cognitive decline, yet the molecular changes underlying brain aging remain poorly understood. Here, we conducted spatiotemporal RNA sequencing of the mouse brain, profiling 1,076 samples from 15 regions across 7 ages and 2 rejuvenation interventions. Our analysis identified a brain-wide gene signature of aging in glial cells, which exhibited spatially defined changes in magnitude. By integrating spatial and single-nucleus transcriptomics, we found that glial aging was particularly accelerated in white matter compared with cortical regions, whereas specialized neuronal populations showed region-specific expression changes. Rejuvenation interventions, including young plasma injection and dietary restriction, exhibited distinct effects on gene expression in specific brain regions. Furthermore, we discovered differential gene expression patterns associated with three human neurodegenerative diseases, highlighting the importance of regional aging as a potential modulator of disease. Our findings identify molecular foci of brain aging, providing a foundation to target age-related cognitive decline.

  View details for DOI 10.1016/j.cell.2023.07.027

  View details for PubMedID 37591239

• Electroacupuncture ameliorates cerebrovascular impairment in Alzheimer's disease mice via melatonin signaling. CNS neuroscience & therapeutics Jiang, Y., Lin, Y., Tan, Y., Shen, X., Liao, M., Wang, H., Lu, N., Han, F., Xu, N., Tang, C., Song, J., Tao, R. 2022

  Abstract

  AIMS: Cerebrovascular impairment contributes to the pathogenesis of Alzheimer's disease (AD). However, it still lacks effective intervention in clinical practice. Here, we investigated the efficacy of electroacupuncture (EA) in cerebrovascular repair in 3xTg-AD mice and its mechanism.METHODS: 3xTg-AD mice were employed to evaluate the protective effect of EA at ST36 acupoint (EAST36). Behavioral tests were performed to assess neurological disorders. Laser speckle contrast imaging, immunostaining, and Western blot were applied to determine EAST36-boosted cerebrovascular repair. The mechanism was explored in 3xTg mice and endothelial cell cultures by melatonin signaling modulation.RESULTS: EAST36 at 20/100Hz effectively alleviated the olfactory impairment and anxiety behavior and boosted cerebrovascular repair in AD mice. EAST36 attenuated cerebral microvascular degeneration in AD mice by modulating endothelial cell viability and injury. Consequently, the Abeta deposits and neural damage in AD mice were reversed after EAST36. Mechanistically, we revealed that EAST36 restored melatonin levels in AD mice. Melatonin supplement mimicked the EAST36 effect on cerebrovascular protection in AD mice and endothelial cell cultures. Importantly, blockage of melatonin signaling by antagonist blunted EAST36-induced cerebrovascular recovery and subsequent neurological improvement.CONCLUSIONS: These findings provided strong evidence to support EAST36 as a potential nonpharmacological therapy against cerebrovascular impairment in AD. Further study is necessary to better understand how EAST36 treatment drives melatonin signaling.

  View details for DOI 10.1111/cns.14027

  View details for PubMedID 36382345

• Young CSF restores oligodendrogenesis and memory in aged mice via Fgf17. Nature Iram, T., Kern, F., Kaur, A., Myneni, S., Morningstar, A. R., Shin, H., Garcia, M. A., Yerra, L., Palovics, R., Yang, A. C., Hahn, O., Lu, N., Shuken, S. R., Haney, M. S., Lehallier, B., Iyer, M., Luo, J., Zetterberg, H., Keller, A., Zuchero, J. B., Wyss-Coray, T. 2022

  Abstract

  Recent understanding of how the systemic environment shapes the brain throughout life has led to numerous intervention strategies to slow brain ageing1-3. Cerebrospinal fluid (CSF) makes up the immediate environment of brain cells, providing them with nourishing compounds4,5. We discovered that infusing young CSF directly into aged brains improves memory function. Unbiased transcriptome analysis of the hippocampus identified oligodendrocytes to be most responsive to this rejuvenated CSF environment. We further showed that young CSF boosts oligodendrocyte progenitor cell (OPC) proliferation and differentiation in the aged hippocampus and in primary OPC cultures. Using SLAMseq to metabolically label nascent mRNA, we identified serum response factor (SRF), a transcription factor that drives actin cytoskeleton rearrangement, as a mediator of OPC proliferation following exposure to young CSF. With age, SRF expression decreases in hippocampal OPCs, and the pathway is induced by acute injection with young CSF. We screened for potential SRF activators in CSF and found that fibroblast growth factor 17 (Fgf17) infusion is sufficient to induce OPC proliferation and long-term memory consolidation in aged mice while Fgf17 blockade impairs cognition in young mice. These findings demonstrate the rejuvenating power of young CSF and identify Fgf17 as a key target to restore oligodendrocyte function in the ageing brain.

  View details for DOI 10.1038/s41586-022-04722-0

  View details for PubMedID 35545674

• Exercise plasma boosts memory and dampens brain inflammation via clusterin. Nature De Miguel, Z., Khoury, N., Betley, M. J., Lehallier, B., Willoughby, D., Olsson, N., Yang, A. C., Hahn, O., Lu, N., Vest, R. T., Bonanno, L. N., Yerra, L., Zhang, L., Saw, N. L., Fairchild, J. K., Lee, D., Zhang, H., McAlpine, P. L., Contrepois, K., Shamloo, M., Elias, J. E., Rando, T. A., Wyss-Coray, T. 2021

  Abstract

  Physical exercise is generally beneficial to all aspects of human and animal health, slowing cognitive ageing and neurodegeneration1. The cognitive benefits of physical exercise are tied to an increased plasticity and reduced inflammation within the hippocampus2-4, yet little is known about the factors and mechanisms that mediate these effects. Here we show that 'runner plasma', collected from voluntarily running mice and infused into sedentary mice, reduces baseline neuroinflammatory gene expression and experimentally induced brain inflammation. Plasma proteomic analysis revealed a concerted increase in complement cascade inhibitors including clusterin (CLU). Intravenously injected CLU binds to brain endothelial cells and reduces neuroinflammatory gene expression in a mouse model of acute brain inflammation and a mouse model of Alzheimer's disease. Patients with cognitive impairment who participated in structured exercise for 6 months had higher plasma levels of CLU. These findings demonstrate the existence of anti-inflammatory exercise factors that are transferrable, target the cerebrovasculature and benefit the brain, and are present in humans who engage in exercise.

  View details for DOI 10.1038/s41586-021-04183-x

  View details for PubMedID 34880498

• Dysregulation of brain and choroid plexus cell types in severe COVID-19. Nature Yang, A. C., Kern, F., Losada, P. M., Agam, M. R., Maat, C. A., Schmartz, G. P., Fehlmann, T., Stein, J. A., Schaum, N., Lee, D. P., Calcuttawala, K., Vest, R. T., Berdnik, D., Lu, N., Hahn, O., Gate, D., McNerney, M. W., Channappa, D., Cobos, I., Ludwig, N., Schulz-Schaeffer, W. J., Keller, A., Wyss-Coray, T. 2021

  Abstract

  Though SARS-CoV-2 primarily targets the respiratory system, patients and survivors can suffer neurological symptoms1-3. Yet, an unbiased understanding of the cellular and molecular processes affected in the brains of COVID-19 patients is still missing. Here, we profile 65,309 single-nucleus transcriptomes from 30 frontal cortex and choroid plexus samples across 14 control (including 1 terminal influenza) and 8 COVID-19 patients. While a systematic analysis yields no molecular traces of SARS-CoV-2 in the brain, we observe broad cellular perturbations which predict that choroid plexus barrier cells sense and relay peripheral inflammation into the brain and show that peripheral T cells infiltrate the parenchyma. We discover COVID-19 disease-associated microglia and astrocyte subpopulations that share features with pathological cell states reported in human neurodegenerative disease4-6. Synaptic signaling of upper-layer excitatory neurons-evolutionarily expanded in humans7 and linked to cognitive function8-are preferentially affected in COVID-19. Across cell types, COVID-19 perturbations overlap with those in chronic brain disorders and reside in genetic variants associated with cognition, schizophrenia, and depression. Our findings and public dataset provide a molecular framework to understand COVID-19 related neurological disease observed now and which may emerge later.

  View details for DOI 10.1038/s41586-021-03710-0

  View details for PubMedID 34153974

• Endothelium-derived semaphorin 3G attenuates ischemic retinopathy by coordinating β-catenin-dependent vascular remodeling. The Journal of clinical investigation Chen, D. Y., Sun, N. H., Chen, X., Gong, J. J., Yuan, S. T., Hu, Z. Z., Lu, N. N., Körbelin, J., Fukunaga, K., Liu, Q. H., Lu, Y. M., Han, F. 2021; 131 (4)

  Abstract

  Abnormal angiogenesis and regression of the diseased retinal vasculature are key processes associated with ischemic retinopathies, but the underlying mechanisms that regulate vascular remodeling remain poorly understood. Here, we confirmed the specific expression of semaphorin 3G (Sema3G) in retinal endothelial cells (ECs), which was required for vascular remodeling and the amelioration of ischemic retinopathy. We found that Sema3G was elevated in the vitreous fluid of patients with proliferative diabetic retinopathy (PDR) and in the neovascularization regression phase of oxygen-induced retinopathy (OIR). Endothelial-specific Sema3G knockout mice exhibited decreased vessel density and excessive matrix deposition in the retinal vasculature. Moreover, loss of Sema3G aggravated pathological angiogenesis in mice with OIR. Mechanistically, we demonstrated that HIF-2α directly regulated Sema3G transcription in ECs under hypoxia. Sema3G coordinated the functional interaction between β-catenin and VE-cadherin by increasing β-catenin stability in the endothelium through the neuropilin-2 (Nrp2)/PlexinD1 receptor. Furthermore, Sema3G supplementation enhanced healthy vascular network formation and promoted diseased vasculature regression during blood vessel remodeling. Overall, we deciphered the endothelium-derived Sema3G-dependent events involved in modulating physiological vascular remodeling and regression of pathological blood vessels for reparative vascular regeneration. Our findings shed light on the protective effect of Sema3G in ischemic retinopathies.

  View details for DOI 10.1172/JCI135296

  View details for PubMedID 33586674

  View details for PubMedCentralID PMC7880421

• Endothelial Cdk5 deficit leads to the development of spontaneous epilepsy through CXCL1/CXCR2-mediated reactive astrogliosis. The Journal of experimental medicine Liu, X. X., Yang, L., Shao, L. X., He, Y., Wu, G., Bao, Y. H., Lu, N. N., Gong, D. M., Lu, Y. P., Cui, T. T., Sun, N. H., Chen, D. Y., Shi, W. X., Fukunaga, K., Chen, H. S., Chen, Z., Han, F., Lu, Y. M. 2020; 217 (1)

  Abstract

  Blood-brain barrier (BBB) dysfunction has been suggested to play an important role in epilepsy. However, the mechanism mediating the transition from cerebrovascular damage to epilepsy remains unknown. Here, we report that endothelial cyclin-dependent kinase 5 (CDK5) is a central regulator of neuronal excitability. Endothelial-specific Cdk5 knockout led to spontaneous seizures in mice. Knockout mice showed increased endothelial chemokine (C-X-C motif) ligand 1 (Cxcl1) expression, decreased astrocytic glutamate reuptake through the glutamate transporter 1 (GLT1), and increased glutamate synaptic function. Ceftriaxone restored astrocytic GLT1 function and inhibited seizures in endothelial Cdk5-deficient mice, and these effects were also reversed after silencing Cxcl1 in endothelial cells and its receptor chemokine (C-X-C motif) receptor 2 (Cxcr2) in astrocytes, respectively, in the CA1 by AAV transfection. These results reveal a previously unknown link between cerebrovascular factors and epileptogenesis and provide a rationale for targeting endothelial signaling as a potential treatment for epilepsy.

  View details for DOI 10.1084/jem.20180992

  View details for PubMedID 31699822

  View details for PubMedCentralID PMC7037235

• Endothelium-Derived Semaphorin 3G Regulates Hippocampal Synaptic Structure and Plasticity via Neuropilin-2/PlexinA4. Neuron Tan, C., Lu, N. N., Wang, C. K., Chen, D. Y., Sun, N. H., Lyu, H., Körbelin, J., Shi, W. X., Fukunaga, K., Lu, Y. M., Han, F. 2019; 101 (5): 920-937.e13

  Abstract

  The proper interactions between blood vessels and neurons are critical for maintaining the strength of neural circuits and cognitive function. However, the precise molecular events underlying these interactions remain largely unknown. Here, we report that the selective knockout of semaphorin 3G (Sema3G) in endothelial cells impaired hippocampal-dependent memory and reduced dendritic spine density in CA1 neurons in mice; these effects were reversed after restoration of Sema3G levels in the hippocampus by AAV transfection. We further show that Sema3G increased excitatory synapse density via neuropilin-2/PlexinA4 signaling and through activation of Rac1. These results provide the first evidence that, in the central nervous system, endothelial Sema3G serves as a vascular-derived synaptic organizer that regulates synaptic plasticity and hippocampal-dependent memory. Our findings highlight the role of vascular endothelial cells in regulating cognitive function through intercellular communication with neurons in the hippocampus.

  View details for DOI 10.1016/j.neuron.2018.12.036

  View details for PubMedID 30685224

• Cholinergic Grb2-Associated-Binding Protein 1 Regulates Cognitive Function. Cerebral cortex (New York, N.Y. : 1991) Lu, N. N., Tan, C., Sun, N. H., Shao, L. X., Liu, X. X., Gao, Y. P., Tao, R. R., Jiang, Q., Wang, C. K., Huang, J. Y., Zhao, K., Wang, G. F., Liu, Z. R., Fukunaga, K., Lu, Y. M., Han, F. 2018; 28 (7): 2391-2404

  Abstract

  Grb2-associated-binding protein 1 (Gab1) is a docking/scaffolding molecule known to play an important role in cell growth and survival. Here, we report that Gab1 is decreased in cholinergic neurons in Alzheimer's disease (AD) patients and in a mouse model of AD. In mice, selective ablation of Gab1 in cholinergic neurons in the medial septum impaired learning and memory and hippocampal long-term potentiation. Gab1 ablation also inhibited SK channels, leading to an increase in firing in septal cholinergic neurons. Gab1 overexpression, on the other hand, improved cognitive function and restored hippocampal CaMKII autorphosphorylation in AD mice. These results suggest that Gab1 plays an important role in the pathophysiology of AD and may represent a novel therapeutic target for diseases involving cholinergic dysfunction.

  View details for DOI 10.1093/cercor/bhx141

  View details for PubMedID 28591834

• A fluorescent peptidyl substrate for visualizing peptidyl-prolyl cis/trans isomerase activity in live cells. Chemical communications (Cambridge, England) Jiang, Q., Li, X. R., Wang, C. K., Cheng, J., Tan, C., Cui, T. T., Lu, N. N., James, T. D., Han, F., Li, X. 2018; 54 (15): 1857-1860

  Abstract

  This communication reports on a fluorescent probe (PPI-P) for imaging active peptidyl-prolyl cis/trans isomerases in live cells. PPI-P is capable of responding to both recombinant and cellular PPIases fluorogenically, and has been shown to specifically image active PPIases in live cells.

  View details for DOI 10.1039/c7cc09135d

  View details for PubMedID 29387835

• Nitration of TRPM2 as a Molecular Switch Induces Autophagy During Brain Pericyte Injury. Antioxidants & redox signaling Jiang, Q., Gao, Y., Wang, C., Tao, R., Wu, Y., Zhan, K., Liao, M., Lu, N., Lu, Y., Wilcox, C. S., Luo, J., Jiang, L. H., Yang, W., Han, F. 2017; 27 (16): 1297-1316

  Abstract

  Dysfunction of neurovascular pericytes underlies breakdown of the blood-brain barrier, but the molecular mechanisms are largely unknown. In this study, we evaluated the role of the transient receptor potential melastatin-related 2 (TRPM2) channel and autophagy during brain pericyte injury both in vitro and in vivo.A rapid induction in autophagy in human brain vascular pericytes, in the zinc oxide nanoparticles (ZnO-NP)-induced cell stress model, was paralleled with an increase in the expression of the TRPM2-S truncated isoform, which was abolished by treatment with a nitric oxide synthase inhibitor and a peroxynitrite scavenger. Furthermore, Y1485 in the C-terminus of the TRPM2 protein was identified as the tyrosine nitration substrate by mass spectrometry. Overexpression of the Y1485S TRPM2 mutant reduced LC3-II accumulation and pericyte injury induced by ZnO-NP. Consistently, LC3-II accumulation was reduced and pericytes were better preserved in intact brain microvessels of the TRPM2 knockout mice after ZnO-NP-induced vascular injury. Innovation and Conclusions: Our present study has revealed a novel mechanism of autophagy disturbance secondary to nitrosative stress-induced tyrosine nitration of TRPM2 during pericyte injury. Antioxid. Redox Signal. 27, 1297-1316.

  View details for DOI 10.1089/ars.2016.6873

  View details for PubMedID 28292196

• Melatonin ameliorates hypoglycemic stress-induced brain endothelial tight junction injury by inhibiting protein nitration of TP53-induced glycolysis and apoptosis regulator. Journal of pineal research Wang, C. K., Ahmed, M. M., Jiang, Q., Lu, N. N., Tan, C., Gao, Y. P., Mahmood, Q., Chen, D. Y., Fukunaga, K., Li, M., Chen, Z., Wilcox, C. S., Lu, Y. M., Qin, Z. H., Han, F. 2017; 63 (4)

  Abstract

  Severe hypoglycemia has a detrimental impact on the cerebrovasculature, but the molecular events that lead to the disruption of the integrity of the tight junctions remain unclear. Here, we report that the microvessel integrity was dramatically compromised (59.41% of wild-type mice) in TP53-induced glycolysis and apoptosis regulator (TIGAR) transgenic mice stressed by hypoglycemia. Melatonin, a potent antioxidant, protects against hypoglycemic stress-induced brain endothelial tight junction injury in the dosage of 400 nmol/L in vitro. FRET (fluorescence resonance energy transfer) imaging data of endothelial cells stressed by low glucose revealed that TIGAR couples with calmodulin to promote TIGAR tyrosine nitration. A tyrosine 92 mutation interferes with the TIGAR-dependent NADPH generation (55.60% decreased) and abolishes its protective effect on tight junctions in human brain microvascular endothelial cells. We further demonstrate that the low-glucose-induced disruption of occludin and Caludin5 as well as activation of autophagy was abrogated by melatonin-mediated blockade of nitrosative stress in vitro. Collectively, we provide information on the detailed molecular mechanisms for the protective actions of melatonin on brain endothelial tight junctions and suggest that this indole has translational potential for severe hypoglycemia-induced neurovascular damage.

  View details for DOI 10.1111/jpi.12440

  View details for PubMedID 28776759

  View details for PubMedCentralID PMC5656838

• Endothelial ErbB4 deficit induces alterations in exploratory behavior and brain energy metabolism in mice. CNS neuroscience & therapeutics Wu, G., Liu, X. X., Lu, N. N., Liu, Q. B., Tian, Y., Ye, W. F., Jiang, G. J., Tao, R. R., Han, F., Lu, Y. M. 2017; 23 (6): 510-517

  Abstract

  The receptor tyrosine kinase ErbB4 is present throughout the primate brain and has a distinct functional profile. In this study, we investigate the potential role of endothelial ErbB4 receptor signaling in the brain.Here, we show that the endothelial cell-specific deletion of ErbB4 induces decreased exploratory behavior in adult mice. However, the water maze task for spatial memory and the memory reconsolidation test reveal no changes; additionally, we observe no impairment in CaMKII phosphorylation in Cdh5Cre;ErbB4f/f mice, which indicates that the endothelial ErbB4 deficit leads to decreased exploratory activity rather than direct memory deficits. Furthermore, decreased brain metabolism, which was measured using micro-positron emission tomography, is observed in the Cdh5Cre;ErbB4f/f mice. Consistently, the immunoblot data demonstrate the downregulation of brain Glut1, phospho-ULK1 (Ser555), and TIGAR in the endothelial ErbB4 conditional knockout mice. Collectively, our findings suggest that endothelial ErbB4 plays a critical role in regulating brain function, at least in part, through maintaining normal brain energy homeostasis.Targeting ErbB4 or the modulation of endothelial ErbB4 signaling may represent a rational pharmacological approach to treat neurological disorders.

  View details for DOI 10.1111/cns.12695

  View details for PubMedID 28421673

  View details for PubMedCentralID PMC6492688

• Endogenous Polysialic Acid Based Micelles for Calmodulin Antagonist Delivery against Vascular Dementia. ACS applied materials & interfaces Wang, X. J., Gao, Y. P., Lu, N. N., Li, W. S., Xu, J. F., Ying, X. Y., Wu, G., Liao, M. H., Tan, C., Shao, L. X., Lu, Y. M., Zhang, C., Fukunaga, K., Han, F., Du, Y. Z. 2016; 8 (51): 35045-35058

  Abstract

  Clinical treatment for vascular dementia still remains a challenge mainly due to the blood-brain barrier (BBB). Here, a micelle based on polysialic acid (PSA), which is a hydrophilic and endogenous carbohydrate polymer, was designed to deliver calmodulin antagonist for therapy of vascular dementia. PSA was first chemically conjugated with octadecylamine (ODA), and the obtained PSA-ODA copolymer could self-assemble into micelle in aqueous solution with a 120.0 μg/mL critical micelle concentration. The calmodulin antagonist loaded PSA-ODA micelle, featuring sustained drug release behavior over a period of 72 h with a 3.6% (w/w) drug content and a 107.0 ± 4.0 nm size was then fabricated. The PSA-ODA micelle could cross the BBB mainly via active endocytosis by brain endothelial cells followed by transcytosis. In a water maze test for spatial learning, calmodulin antagonist loaded PSA-ODA micelle significantly reduced the escape latencies of right unilateral common carotid arteries occlusion (rUCCAO) mice with dosage significantly reduced versus free drug. The decrease of hippocampal phospho-CaMKII (Thr286/287) and phospho-synapsin I (Ser603) was partially restored in rUCCAO mice following calmodulin antagonist loaded PSA-ODA micelle treatment. Consistent with the restored CaMKII phosphorylation, the elevation of BrdU/NeuN double-positive cells in the same context was also observed. Overall, the PSA-ODA micelle developed from the endogenous material might promote the development of therapeutic approaches for improving the efficacy of brain-targeted drug delivery and have great potential for vascular dementia treatment.

  View details for DOI 10.1021/acsami.6b13052

  View details for PubMedID 27750011

• Visualizing peroxynitrite fluxes in endothelial cells reveals the dynamic progression of brain vascular injury. Journal of the American Chemical Society Li, X., Tao, R. R., Hong, L. J., Cheng, J., Jiang, Q., Lu, Y. M., Liao, M. H., Ye, W. F., Lu, N. N., Han, F., Hu, Y. Z., Hu, Y. H. 2015; 137 (38): 12296-303

  Abstract

  Accumulating evidence suggests that formation of peroxynitrite (ONOO(-)) in the cerebral vasculature contributes to the progression of ischemic damage, while the underlying molecular mechanisms remain elusive. To fully understand ONOO(-) biology, efficient tools that can realize the real-time tracing of endogenous ONOO(-) fluxes are indispensable. While a few ONOO(-) fluorescent probes have been reported, direct visualization of ONOO(-) fluxes in the cerebral vasculature of live mice remains a challenge. Herein, we present a fluorescent switch-on probe (NP3) for ONOO(-) imaging. NP3 exhibits good specificity, fast response, and high sensitivity toward ONOO(-) both in vitro and in vivo. Moreover, NP3 is two-photon excitable and readily blood-brain barrier penetrable. These desired photophysical and pharmacokinetic properties endow NP3 with the capability to monitor brain vascular ONOO(-) generation after injury with excellent temporal and spatial resolution. As a proof of concept, NP3 has enabled the direct visualization of neurovascular ONOO(-) formation in ischemia progression in live mouse brain by use of two-photon laser scanning microscopy. Due to these favorable properties, NP3 holds great promise for visualizing endogenous peroxynitrite fluxes in a variety of pathophysiological progressions in vitro and in vivo.

  View details for DOI 10.1021/jacs.5b06865

  View details for PubMedID 26352914

• P2RX7 sensitizes Mac-1/ICAM-1-dependent leukocyte-endothelial adhesion and promotes neurovascular injury during septic encephalopathy. Cell research Wang, H., Hong, L. J., Huang, J. Y., Jiang, Q., Tao, R. R., Tan, C., Lu, N. N., Wang, C. K., Ahmed, M. M., Lu, Y. M., Liu, Z. R., Shi, W. X., Lai, E. Y., Wilcox, C. S., Han, F. 2015; 25 (6): 674-90

  Abstract

  Septic encephalopathy (SE) is a critical factor determining sepsis mortality. Vascular inflammation is known to be involved in SE, but the molecular events that lead to the development of encephalopathy remain unclear. Using time-lapse in vivo two-photon laser scanning microscopy, we provide the first direct evidence that cecal ligation and puncture in septic mice induces microglial trafficking to sites adjacent to leukocyte adhesion on inflamed cerebral microvessels. Our data further demonstrate that septic injury increased the chemokine CXCL1 level in brain endothelial cells by activating endothelial P2RX7 and eventually enhanced the binding of Mac-1 (CD11b/CD18)-expressing leukocytes to endothelial ICAM-1. In turn, leukocyte adhesion upregulated endothelial CX3CL1, thereby triggering microglia trafficking to the injured site. The sepsis-induced increase in endothelial CX3CL1 was abolished in CD18 hypomorphic mutant mice. Inhibition of the P2RX7 pathway not only decreased endothelial ICAM-1 expression and leukocyte adhesion but also prevented microglia overactivation, reduced brain injury, and consequently doubled the early survival of septic mice. These results demonstrate the role of the P2RX7 pathway in linking neurovascular inflammation to brain damage in vivo and provide a rationale for targeting endothelial P2RX7 for neurovascular protection during SE.

  View details for DOI 10.1038/cr.2015.61

  View details for PubMedID 25998681

  View details for PubMedCentralID PMC4456628

• Atg5 deficit exaggerates the lysosome formation and cathepsin B activation in mice brain after lipid nanoparticles injection. Nanomedicine : nanotechnology, biology, and medicine Lu, N. N., Liu, J., Tian, Y., Liao, M. H., Wang, H., Lu, Y. M., Tao, R. R., Hong, L. J., Liu, S. S., Fukunaga, K., Du, Y. Z., Han, F. 2014; 10 (8): 1843-52

  Abstract

  The present study was designed to investigate the role of autophagy-lysosome signaling in the brain after application of nanoparticles. Here, lipid nanoparticles (LNs) induced elevations of Atg5, P62, LC3 and cathepsin B in mice brain. The transmission electron microscopy revealed a dramatic elevation of lysosome vacuoles colocalized with LNs cluster inside the neurons in mice brain. Immunoblot data revealed abnormal expression of cathepsin B in brain cortex following LNs injection, whereas its expression was further elevated in Atg5(+/-) mice. The importance of Atg5 in the LNs-induced autophagy-lysosome cascade was further supported by our finding that neurovascular response was exaggerated in Atg5(+/-) mice. In addition, the siRNA knockdown of Atg5 significantly blunted the increasing of LC3 and P62 in LNs-treated Neuro-2a cells. Taken together, we propose that LNs induce autophagy-lysosome signaling and neurovascular response at least partially via an Atg5-dependent pathway.These authors investigated autophagy-lysosome signaling in the mouse brain after application of lipid nanoparticles and report that these nanoparticles induce autophagy-lysosome signaling and neurovascular response at least partially via an Atg5-dependent pathway.

  View details for DOI 10.1016/j.nano.2014.03.019

  View details for PubMedID 24768629

• Peroxiredoxin 1 participates in ischemia-triggered endothelial polarization. CNS neuroscience & therapeutics Ye, W. F., Tao, R. R., Jiang, Q., Huang, J. Y., Lu, N. N., Lu, Y. M., Fukunaga, K., Wang, H., Han, F. 2014; 20 (8): 791-3

  View details for DOI 10.1111/cns.12287

  View details for PubMedID 24863454

  View details for PubMedCentralID PMC6493060

• Nitrosative stress induces peroxiredoxin 1 ubiquitination during ischemic insult via E6AP activation in endothelial cells both in vitro and in vivo. Antioxidants & redox signaling Tao, R. R., Wang, H., Hong, L. J., Huang, J. Y., Lu, Y. M., Liao, M. H., Ye, W. F., Lu, N. N., Zhu, D. Y., Huang, Q., Fukunaga, K., Lou, Y. J., Shoji, I., Wilcox, C. S., Lai, E. Y., Han, F. 2014; 21 (1): 1-16

  Abstract

  Although there is accumulating evidence that increased formation of reactive nitrogen species in cerebral vasculature contributes to the progression of ischemic damage, but the underlying molecular mechanisms remain elusive. Peroxiredoxin 1 (Prx1) can initiate the antioxidant response by scavenging free radicals. Therefore, we tested the hypothesis that Prx1 regulates the susceptibility to nitrosative stress damage during cerebral ischemia in vitro and in vivo.Proteomic analysis in endothelial cells revealed that Prx1 was upregulated after stress-related oxygen-glucose deprivation (OGD). Although peroxynitrite upregulated Prx1 rapidly, this was followed by its polyubiquitination within 6 h after OGD mediated by the E3 ubiquitin ligase E6-associated protein (E6AP). OGD colocalized E6AP with nitrotyrosine in endothelial cells. To assess translational relevance in vivo, mice were studied after middle cerebral artery occlusion (MCAO). This was accompanied by Prx1 ubiquitination and degradation by the activation of E6AP. Furthermore, brain delivery of a lentiviral vector encoding Prx1 in mice inhibited blood-brain barrier leakage and neuronal damage significantly following MCAO.Nitrosative stress during ischemic insult activates E6AP E3 ubiquitin ligase that ubiquitinates Prx1 and subsequently worsens cerebral damage. Thus, targeting the Prx1 antioxidant defense pathway may represent a novel treatment strategy for neurovascular protection in stroke.

  View details for DOI 10.1089/ars.2013.5381

  View details for PubMedID 24295341

  View details for PubMedCentralID PMC4048580