Axon guidance factor netrin-1 and its receptors regulate angiogenesis after cerebral ischemia

Carotid artery transplantation of brain endothelial cells enhances neuroprotection and neurorepair in ischaemic stroke rats

Brain microvascular endothelial cells (BMECs), an important component of the neurovascular unit, can promote angiogenesis and synaptic formation in ischaemic mice after brain parenchyma transplantation. Since the therapeutic efficacy of cell-based therapies depends on the extent of transplanted cell residence in the target tissue and cell migration ability, the delivery route has become a hot research topic. In this study, we investigated the effects of carotid artery transplantation of BMECs on neuronal injury, neurorepair, and neurological dysfunction in rats after cerebral ischaemic attack. Purified passage 1 endothelial cells (P1-BMECs) were prepared from mouse brain tissue. Adult rats were subjected to transient middle cerebral artery occlusion (MCAO) for 30 min. Then, the rats were treated with 5 × 105 P1-BMECs through carotid artery infusion or tail vein injection. We observed that carotid artery transplantation of BMECs produced more potent neuroprotective effects than caudal injection in MCAO rats, including reducing infarct size and alleviating neurological deficits in behavioural tests. Carotid artery-transplanted BMECs displayed a wider distribution in the ischaemic rat brain. Immunostaining for endothelial progenitor cells and the mature endothelial cell markers CD34 and RECA-1 showed that carotid artery transplantation of BMECs significantly increased angiogenesis. Carotid artery transplantation of BMECs significantly increased the number of surviving neurons, decreased the cerebral infarction volume, and alleviated neurological deficits. In addition, we found that carotid artery transplantation of BMECs significantly enhanced ischaemia-induced hippocampal neurogenesis, as measured by doublecortin (DCX) and Ki67 double staining within 2 weeks after ischaemic injury. We conclude that carotid artery transplantation of BMECs can promote cerebral angiogenesis, neurogenesis, and neurological function recovery in adult rats after ischaemic stroke. Our results suggest that carotid injection of BMECs may be a promising new approach for treating acute brain injuries.

Molecular Mechanisms of Ischemic Stroke: A Review Integrating Clinical Imaging and Therapeutic Perspectives

Ischemic stroke poses a significant global health challenge, necessitating ongoing exploration of its pathophysiology and treatment strategies. This comprehensive review integrates various aspects of ischemic stroke research, emphasizing crucial mechanisms, therapeutic approaches, and the role of clinical imaging in disease management. It discusses the multifaceted role of Netrin-1, highlighting its potential in promoting neurovascular repair and mitigating post-stroke neurological decline. It also examines the impact of blood-brain barrier permeability on stroke outcomes and explores alternative therapeutic targets such as statins and sphingosine-1-phosphate signaling. Neurocardiology investigations underscore the contribution of cardiac factors to post-stroke mortality, emphasizing the importance of understanding the brain-heart axis for targeted interventions. Additionally, the review advocates for early reperfusion and neuroprotective agents to counter-time-dependent excitotoxicity and inflammation, aiming to preserve tissue viability. Advanced imaging techniques, including DWI, PI, and MR angiography, are discussed for their role in evaluating ischemic penumbra evolution and guiding therapeutic decisions. By integrating molecular insights with imaging modalities, this interdisciplinary approach enhances our understanding of ischemic stroke and offers promising avenues for future research and clinical interventions to improve patient outcomes.

Brain-derived endothelial cells are neuroprotective in a chronic cerebral hypoperfusion mouse model

Whether organ-specific regeneration is induced by organ-specific endothelial cells (ECs) remains unelucidated. The formation of white matter lesions due to chronic cerebral hypoperfusion causes cognitive decline, depression, motor dysfunction, and even acute ischemic stroke. Vascular ECs are an important target for treating chronic cerebral hypoperfusion. Brain-derived ECs transplanted into a mouse chronic cerebral hypoperfusion model showed excellent angiogenic potential. They were also associated with reducing both white matter lesions and brain dysfunction possibly due to the high expression of neuroprotective humoral factors. The in vitro coculture of brain cells with ECs from several diverse organs suggested the function of brain-derived endothelium is affected within a brain environment due to netrin-1 and Unc 5B systems. We found brain CD157-positive ECs were more proliferative and beneficial in a mouse model of chronic cerebral hypoperfusion than CD157-negative ECs upon inoculation. We propose novel methods to improve the symptoms of chronic cerebral hypoperfusion using CD157-positive ECs.

Bioengineering Cell Therapy for Treatment of Peripheral Artery Disease

Peripheral artery disease is an atherosclerotic disease associated with limb ischemia that necessitates limb amputation in severe cases. Cell therapies comprised of adult mononuclear or stromal cells have been clinically tested and show moderate benefits. Bioengineering strategies can be applied to modify cell behavior and function in a controllable fashion. Using mechanically tunable or spatially controllable biomaterials, we highlight examples in which biomaterials can increase the survival and function of the transplanted cells to improve their revascularization efficacy in preclinical models. Biomaterials can be used in conjunction with soluble factors or genetic approaches to further modulate the behavior of transplanted cells and the locally implanted tissue environment in vivo. We critically assess the advances in bioengineering strategies such as 3-dimensional bioprinting and immunomodulatory biomaterials that can be applied to the treatment of peripheral artery disease and then discuss the current challenges and future directions in the implementation of bioengineering strategies.

Angiogenesis after ischemic stroke

Owing to its high disability and mortality rates, stroke has been the second leading cause of death worldwide. Since the pathological mechanisms of stroke are not fully understood, there are few clinical treatment strategies available with an exception of tissue plasminogen activator (tPA), the only FDA-approved drug for the treatment of ischemic stroke. Angiogenesis is an important protective mechanism that promotes neural regeneration and functional recovery during the pathophysiological process of stroke. Thus, inducing angiogenesis in the peri-infarct area could effectively improve hemodynamics, and promote vascular remodeling and recovery of neurovascular function after ischemic stroke. In this review, we summarize the cellular and molecular mechanisms affecting angiogenesis after cerebral ischemia registered in PubMed, and provide pro-angiogenic strategies for exploring the treatment of ischemic stroke, including endothelial progenitor cells, mesenchymal stem cells, growth factors, cytokines, non-coding RNAs, etc.

Netrin-1 controls inflammation in response to ischemic stroke through altering microglia phenotype

Introduction

The current approaches that are used to treat ischemic stroke suffer from poor targeting, lack of effectiveness, and potential off-target effects, necessitating the development of new therapeutic strategies to enhance neuronal cell survival and regeneration. This study aimed to investigate the role of microglial Netrin-1 in ischemic stroke, a topic that has not been fully understood.

Methods

Netrin-1 levels and its primary receptor expressions were investigated in cerebral microglia from acute ischemic stroke patients and age-matched control subjects. A public database (GEO148350), which supplied RNAseq results for rat cerebral microglia in a middle cerebral artery occlusion (MCAO) model, was analyzed to assess the expression of Netrin-1, its major receptors, and genes related to macrophage function. A microglia-specific gene targeting approach and a delivery system allowing for crossing the blood-brain barrier were applied in a mouse model for ischemic stroke to investigate the role of microglial Netrin-1. Netrin-1 receptor signaling in microglia was observed and the effects on microglial phenotype, apoptosis, and migration were analyzed.

Results

Across human patients, rat and mouse models, activation of Netrin-1 receptor signaling was mainly conducted via its receptor UNC5a in microglia, which resulted in a shift in microglial phenotype towards an anti-inflammatory or M2-like state, leading to a reduction in apoptosis and migration of microglia. Netrin-1-induced phenotypic change in microglia exerted protective effects on neuronal cells in vivo during ischemic stroke.

Conclusion

Our study highlights the potential of targeting Netrin-1 and its receptors as a promising therapeutic strategy for promoting post-ischemic survival and functional recovery.

Core-shell oxygen-releasing fibers for annulus fibrosus repair in the intervertebral disc of rats

The repair of annulus fibrosus (AF) defect after discectomy in the intervertebral disc (IVD) has presented a challenge over the past decade. Hostile microenvironments in the IVD, including, compression and hypoxia, are critical issues that require special attention. Till date, little information is available on potential strategies to cope with the hypoxia dilemma in AF defect sites. In this study, perfluorotributylamine (PFTBA) core-shell fibers were fabricated by coaxial electrospinning to construct oxygen-releasing scaffold for promoting endogenous repair in the AF after discectomy. We demonstrated that PFTBA fibers (10% chitosan, chitosan: PCL, 1:6) could release oxygen for up to 144 ​h. The oxygen released from PFTBA fibers was found to protect annulus fibrosus stem cells (AFSCs) from hypoxia-induced apoptosis. In addition, the PFTBA fibers were able to promote proliferation, migration and extracellular matrix (ECM) production in AFSCs under hypoxia, highlighting their therapeutic potential in AF defect repair. Subsequent in vivo studies demonstrated that oxygen-supplying fibers were capable of ameliorating disc degeneration after discectomy, which was evidenced by improved disc height and morphological integrity in rats with the oxygen-releasing scaffolds. Further transcriptome analysis indicated that differential expression genes (DEGs) were enriched in "oxygen transport" and "angiogenesis", which likely contributed to their beneficial effect on endogenous AF regeneration. In summary, the oxygen-releasing scaffold provides novel insights into the oxygen regulation by bioactive materials and raises the therapeutic possibility of oxygen supply strategies for defect repair in AF, as well as other aerobic tissues.

Netrin-1 mediates nerve innervation and angiogenesis leading to discogenic pain

Objective

Discogenic low back pain (LBP) is associated with nociceptive nerve fibers that grow into degenerated intervertebral discs (IVD) but the etiopathogenesis of disease is not fully understood. The purpose of this study was to clarify the role of Netrin-1 in causing discogenic LBP.

Methods

The level of nociceptive nerve innervation was examined in disc degenerative patients and rat needle-punctured models by immunohistochemistry. Nucleus pulposus (NP) cells were isolated from IVD tissues of rats and induced degeneration by interleukin-1β (IL-1β) or tumor necrosis factor α (TNFα). The candidate genes related to neuron outgrowth and migration were selected by Next-generation sequencing (NGS). CRISPR/Cas9 was used to knockdown Netrin-1 in NP cells. The impact of Netrin-1 on nerve innervation were evaluated with P2X2、NF200 staining and microfluidics assay. Meanwhile the CD31 staining and transwell assay were used to evaluate the impact of Netrin-1 in angiogenesis. The proteins and RNA extracted from NP cells related to catabolism and anabolism were examined by western blot assay and RT-qPCR experiment. ChIP and luciferase experiments were used to assess the intracellular transcriptional regulation of Netrin-1. Further, a needle-punctured rat model followed by histomorphometry and immunofluorescence histochemistry was used to explore the potential effect of Netrin-1 on LBP in vivo.

Results

The level of nerve innervation was increased in severe disc degenerative patients while the expression of Netrin-1 was upregulated. The supernatants of NP cells stimulated with IL-1β or TNFα containing more Netrin-1 could promote axon growth and vascular endothelial cells migration. Knocking down Netrin-1 or overexpressing transcription factor TCF3 as a negative regulator of Netrin-1 attenuated this effect. The needle-punctured rat model brought significant spinal hypersensitivity, nerve innervation and angiogenesis, nevertheless knocking down Netrin-1 effectively prevented disc degeneration-induced adverse impacts.

Conclusion

Discogenic LBP was induced by Netrin-1, which mediated nerve innervation and angiogenesis in disc degeneration. Knocking down Netrin-1 by CRISPR/Cas9 or negatively regulating Netrin1 by transcription factor TCF3 could alleviate spinal hypersensitivity.

The translational potential of this article

This study on Netrin-1 could provide a new target and theoretical basis for the prevention and treatment for discogenic back pain.

Niacin mitigates blood-brain barrier tight junctional proteins dysregulation and cerebral inflammation in ketamine rat model of psychosis: Role of GPR109A receptor

Dysregulated inflammatory responses and blood-brain barrier (BBB) dysfunction are recognized as central factors in the development of psychiatric disorders. The present study was designed to evaluate the effect of niacin on BBB integrity in ketamine-induced model of psychosis. Meanwhile, mepenzolate bromide (MPN), a GPR109A receptor blocker, was used to investigate the role of this receptor on the observed niacin's effect. Male Wistar rats received ketamine (30 mg/kg/day, i.p) for 5 consecutive days and then niacin (40 mg/kg/day, p.o), with or without MPN (5 mg/kg/day, i.p), was given for the subsequent 15 days. Three days before the end of experiment, rats were behaviorally tested using open field, novel object recognition, social interaction, and forced swimming tests. Niacin significantly ameliorated ketamine-induced behavioral deficits, amended gamma aminobutyric acid and glutamate concentration, decreased tumor necrosis factor-α and matrix metallopeptidase 9 levels, and increased netrin-1 contents in the hippocampus of rats. Niacin also augmented the hippocampal expression of ZO-1, occludin, and claudin-5 proteins, indicating the ability of niacin to restore the BBB integrity. Moreover, the histopathologic changes in hippocampal neurons were alleviated. Since all the beneficial effects of niacin in the present investigation were partially abolished by the co-administration of MPN; GPR109A receptor was proven to partially mediate the observed antipsychotic effects of niacin. These data revealed that GPR109A-mediated signaling pathways might represent potential targets for therapeutic interventions to prevent or slow the progression of psychosis.

Netrin-1 Secreted by Human Osteoarthritic Articular Chondrocytes Promotes Angiogenesis in Vitro

OBJECTIVE

Netrin-1 expression in articular cartilage is correlated with osteoarthritic changes. We aimed to investigate the contribution of Netrin-1 secreted by human osteoarthritic articular chondrocytes to angiogenesis process in vitro.

DESIGN

Human articular chondrocytes were extracted from non-osteoarthritic (n = 10) and osteoarthritic (n = 22) joints obtained from surgical specimens and incubated for 24 hours. Medium conditioned by non-osteoarthritic and osteoarthritic articular chondrocytes were collected. Human umbilical vein endothelial cells (HUVEC) were treated with control and conditioned medium and assessed using assays for cell adherence, migration, and tube formation. Netrin-1 expression and secretion was compared between non-osteoarthritic and osteoarthritic chondrocytes by qPCR, Western blot, and ELISA. The role of chondrocyte-secreted Netrin-1 on HUVEC functions was assessed by immunological neutralization using an anti-Netrin-1 monoclonal antibody.

RESULTS

As compared with medium conditioned by non-osteoarthritic chondrocytes, medium conditioned by osteoarthritic chondrocytes permitted tube formation by HUVEC. Both non-osteoarthritic and osteoarthritic chondrocytes expressed Netrin-1 at the RNA and protein levels. At the RNA level, Netrin-1 expression did not differ between non-osteoarthritic and osteoarthritic chondrocytes. At the protein level, Netrin-1 appeared as a full protein of 64 kDa in non-osteoarthritic chondrocytes and as two cleaved proteins of 55 kDa and 64 kDa in osteoarthritic chondrocytes. Immunological neutralization of endogenous Netrin-1 reduced the pro-angiogenic and pro-inflammatory transcriptional profile of HUVEC treated with the medium conditioned by osteoarthritic chondrocytes, as well as their capacities to form tubes.

CONCLUSIONS

Medium conditioned by osteoarthritic chondrocytes permits tube formation by HUVEC in vitro. This permissive effect is mediated by Netrin-1.

Netrin-1 in Post-stroke Neuroprotection: Beyond Axon Guidance Cue

BACKGROUND

Stroke, especially ischemic stroke, is a leading disease associated with death and long-term disability with limited therapeutic options. Neuronal death caused by vascular impairment, programmed cell death and neuroinflammation has been proven to be associated with increased stroke severity and poor stroke recovery. In light of this, a development of neuroprotective drugs targeting injured neurons is urgently needed for stroke treatment. Netrin-1, known as a bifunctional molecule, was originally described to mediate the repulsion or attraction of axonal growth by interacting with its different receptors. Importantly, accumulating evidence has shown that netrin-1 can manifest its beneficial functions to brain tissue repair and neural regeneration in different neurological disease models.

OBJECTIVE

In this review, we focus on the implications of netrin-1 and its possibly involved pathways on neuroprotection after ischemic stroke, through which a better understanding of the underlying mechanisms of netrin-1 may pave the way to novel treatments.

METHODS

Peer-reviewed literature was recruited by searching databases of PubMed, Scopus, Embase, and Web of Science till the year 2021.

CONCLUSION

There has been certain evidence to support the neuroprotective function of netrin-1 by regulating angiogenesis, autophagy, apoptosis and neuroinflammation after stroke. Netrin-1 may be a promising drug candidate in reducing stroke severity and improving outcomes.

Adhesive hydrogel wrap loaded with Netrin-1-modified adipose-derived stem cells: An effective approach against periarterial inflammation after endovascular intervention

Endovascular interventions, such as balloon dilation and stent implantation, are currently recommended as the primary treatment for patients with peripheral artery disease (PAD), greatly improving patient prognosis. However, the consequent lumen restenosis that occurs after endovascular interventions has become an important clinical problem. Inflammation has been proven to be crucial to postoperative restenosis. In previous studies we have identified that Netrin-1-modified adipose-derived stem cells (N-ADSCs) transplantation is an effective anti-inflammatory strategy to repair vascular damage. Nevertheless, it remained to be explored how one could constantly deliver N-ADSCs onto damaged arteries. Therefore, we developed an adhesive double network (DN) hydrogel wrap loaded with N-ADSCs for sustained perivascular delivery. Inspired by the adhesion mechanism of mussels, we developed an adhesive and tough polyacrylamide/calcium-alginate/reduced graphene oxide/polydopamine (PAM/CA/rGO/PDA) hydrogel. Dopamine was attached to graphene sheets and limitedly oxidized to generate free catechol groups. The hydrogel could wrap damaged arteries and induce anti-inflammatory effects through N-ADSCs. In vitro experiments demonstrated that N-ADSCs significantly promoted the M2 polarization of macrophages to anti-inflammatory phenotypes and reduced the expression of inflammatory factors. In vivo experiments in a rat carotid artery guidewire injury model showed that the adhesive hydrogel wrap loaded with N-ADSCs could significantly reduce arterial inflammation, inhibit intimal hyperplasia and improve re-endothelialization. Altogether, this newly developed N-ADSCs-loaded hydrogel wrap provides an effective slow-releasing system, which may be a promising way to prevent and treat restenosis after endovascular interventions.

The Alteration Profiles of m6A-Tagged circRNAs in the Peri-Infarct Cortex After Cerebral Ischemia in Mice

The N6-methyladenosine (m⁶A) modification acts as a dynamic regulatory factor in diseases by regulating the metabolism and function of the transcriptome, especially mRNAs. However, little is known regarding the functional effects of m⁶A modifications on circRNAs. In this research, we established a distal middle cerebral artery occlusion (MCAO) model in adult C57BL/6J mice. The mice were divided into three groups: sham surgery, 3 days after MCAO (3d), and 7 days after MCAO (7d). Reverse transcription quantitative polymerase chain reaction (RT-qPCR) demonstrated that the mRNA expression levels of m⁶A-related methyltransferases (METTL3, METTL14), demethylases (FTO, ALKBH5), and reading proteins (YTHDF1, YTHDF3) altered compared to the sham group. Furthermore, the translation level of ALKBH5 and YTHDF3 was significantly decreased in the 3d group while increased in 7d group. Methylated RNA immunoprecipitation (MeRIP) and circRNA microarray indicated 85 hypermethylated and 1621 hypomethylated circRNAs in the 3d group. In the 7d group, the methylation level increased in 57 and decreased in 66 circRNAs. Subsequently, our results were verified by MeRIP-qPCR. Bioinformatics analysis was performed to analyze the functions of differentially m⁶A-modified circRNAs. We found some m⁶A modified-circRNAs associated with cerebral infarction, providing a new direction for the molecular mechanism of stroke.

Magnetic Resonance Imaging Investigation of Neuroplasticity After Ischemic Stroke in Tetramethylpyrazine-Treated Rats

Ischemic stroke elicits white matter injury typically signed by axonal disintegration and demyelination; thus, the development of white matter reorganization is needed. 2,3,5,6-Tetramethylpyrazine (TMP) is widely used to treat ischemic stroke. This study was aimed to investigate whether TMP could protect the white matter and promote axonal repair after cerebral ischemia. Male Sprague–Dawley rats were subjected to permanent middle cerebral artery occlusion (MCAO) and treated with TMP (10, 20, 40 mg/kg) intraperitoneally for 14 days. The motor function related to gait was evaluated by the gait analysis system. Multiparametric magnetic resonance imaging (MRI) was conducted to noninvasively identify gray-white matter structural integrity, axonal reorganization, and cerebral blood flow (CBF), followed by histological analysis. The expressions of axonal growth-associated protein 43 (GAP-43), synaptophysin (SYN), axonal growth-inhibitory signals, and guidance factors were measured by Western blot. Our results showed TMP reduced infarct volume, relieved gray-white matter damage, promoted axonal remodeling, and restored CBF along the peri-infarct cortex, external capsule, and internal capsule. These MRI findings were confirmed by histopathological data. Moreover, motor function, especially gait impairment, was improved by TMP treatment. Notably, TMP upregulated GAP-43 and SYN and enhanced axonal guidance cues such as Netrin-1/DCC and Slit-2/Robo-1 but downregulated intrinsic growth-inhibitory signals NogoA/NgR/RhoA/ROCK-2. Taken together, our data indicated that TMP facilitated poststroke axonal remodeling and motor functional recovery. Moreover, our findings suggested that TMP restored local CBF, augmented guidance cues, and restrained intrinsic growth-inhibitory signals, all of which might improve the intracerebral microenvironment of ischemic areas and then benefit white matter remodeling.

CD146 mediates the anti-apoptotic role of Netrin-1 in endothelial progenitor cells under hypoxic conditions

Modulating the biological status of endothelial progenitor cells (EPCs), such as function and survival, is essential for therapeutic angiogenesis in ischemic vascular disease environments. This study aimed to explore the role and molecular mechanisms underlying Netrin-1 in the viability and angiogenic function of EPCs. EPCs were isolated from the bone barrow of adult C57/BL6 mice. The apoptosis and various functions of EPCs were analyzed in vitro by manipulating the expression of Netrin-1. The TUNEL assay was performed to detect apoptotic EPCs. Cell migration and tube formation assays were performed to detect EPC function. Trypan blue staining was performed to detect cell viability. Western blot analysis was performed to detect the protein expression levels of Netrin-1, CD146 and apoptotic factors. Quantitative PCR analysis was performed to detect the expression levels of Netrin-1 receptors. The results demonstrated that treatment with exogenous Netrin-1 promoted EPC migration and tube formation, whereas transfection with small interfering (si)RNA targeting Netrin-1 exhibited the opposite effects. Exogenous Netrin-1 protected EPCs from hypoxia-induced apoptosis, whereas the interruption of endogenous Netrin-1 enhancement under hypoxia by Netrin-1-siRNA exacerbated the apoptosis of EPCs. Furthermore, CD146, one of the immunoglobulin receptors activated by Netrin-1, was screened for in the present study. Results demonstrated that CD146 did not participate in Netrin-1-promoted EPC function, but mediated the anti-apoptotic effects of Netrin-1 in EPCs. In conclusion, Netrin-1 enhanced the angiogenic function of EPCs and alleviated hypoxia-induced apoptosis, which was mediated by CD146. This biological function of Netrin-1 may provide a potential therapeutic option to promote EPCs for the treatment of ischemic vascular diseases.

Xyloketal B: A marine compound with medicinal potential

In recent decades, technological advantages have allowed scientists to isolate medicinal compounds from marine organisms that exhibit unique structure and bioactivity. The mangrove fungus Xylaria sp. from the South China Sea is rich in metabolites and produces a potent therapeutic compound, xyloketal B. Since its isolation in 2001, xyloketal B has been extensively studied in a wide variety of cell types and in vitro and in vivo disease models. Xyloketal B and its derivatives exhibit cytoprotective effects in cardiovascular and neurodegenerative diseases by reducing oxidative stress, regulating the apoptosis pathway, maintaining ionic balance, mitigating inflammatory responses, and preventing protein aggregation. Xyloketal B has also shown to alleviate lipid accumulation in a non-alcoholic fatty liver disease model. Moreover, xyloketal B treatment induces glioblastoma cell death. This review summarizes our current understanding of xyloketal B in various disease models.

Bioinformatic Analysis of Exosomal MicroRNAs of Cerebrospinal Fluid in Ischemic Stroke Rats After Physical Exercise

Physical exercise is beneficial to the structural and functional recovery of post-ischemic stroke, but its molecular mechanism remains obscure. Herein, we aimed to explore the underlying mechanism of exercise-induced neuroprotection from the perspective of microRNAs (miRNAs). Adult male Sprague-Dawley (SD) rats were randomly distributed into 4 groups, i.e., the physical exercise group with the transient middle cerebral artery occlusion (tMCAO) surgery (PE-IS, n = 28); the physical exercise group without tMCAO surgery (PE, n = 6); the sedentary group with tMCAO surgery (Sed-IS, n = 28); and the sedentary group without tMCAO surgery (Sed, n = 6). Notably, rats in the PE-IS and PE groups were subjected to a running exercise for 28 days while rats in the Sed-IS and Sed groups received no exercise training. After long-term exercise, exosomal miRNAs of cerebrospinal fluid (CSF) were analyzed using high-throughput sequencing. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were employed for the differentially expressed miRNAs. Physical exercise improved the neurological function and attenuated the lesion expansion after stroke. In total, 41 differentially expressed miRNAs were screened for the GO and KEGG analysis. GO enriched terms were associated with the central nervous system, including cellular response to retinoic acid, vagus nerve morphogenesis, cellular response to hypoxia, dendritic cell chemotaxis, cell differentiation, and regulation of neuron death. Besides, these differentially expressed miRNAs were linked to the pathophysiological process of stroke, including axon guidance, NF-kappa B signaling pathway, thiamine metabolism, and MAPK signaling pathway according to KEGG analysis. In summary, exercise training significantly alleviated the neurological damage at both functional and structural levels. Moreover, the differentially expressed miRNAs regulating multiple signal pathways were potentially involved in the neuroprotective effects of physical exercise. Therefore, these miRNAs altered by physical exercise might represent the therapeutic strategy for cerebral ischemia.

Vascular Sema3E-Plexin-D1 Signaling Reactivation Promotes Post-stroke Recovery through VEGF Downregulation in Mice

Post-stroke vascular remodeling, including angiogenesis, facilitates functional recovery. Proper vascular repair is important for efficient post-stroke recovery; however, the underlying mechanisms coordinating the diverse signaling pathways involved in vascular remodeling remain largely unknown. Recently, axon guidance molecules were revealed as key players in injured vessel remodeling. One such molecule, Semaphorin 3E (Sema3E), and its receptor, Plexin-D1, control vascular development by regulating vascular endothelial growth factor (VEGF) signaling. In this study, using a mouse model of transient brain infarction, we aimed to investigate whether Sema3E-Plexin-D1 signaling was involved in cerebrovascular remodeling after ischemic injury. We found that ischemic damage rapidly induced Sema3e expression in the neurons of peri-infarct regions, followed by Plexin-D1 upregulation in remodeling vessels. Interestingly, Plexin-D1 reemergence was concurrent with brain vessels entering an active angiogenic process. In line with this, Plxnd1 ablation worsened neurological deficits, infarct volume, neuronal survival rate, and blood flow recovery. Furthermore, reduced and abnormal vascular morphogenesis was caused by aberrantly increased VEGF signaling. In Plxnd1 knockout mice, we observed significant extravasation of intravenously administered tracers in the brain parenchyma, junctional protein downregulation, and mislocalization in regenerating vessels. This suggested that the absence of Sema3E-Plexin-D1 signaling is associated with blood–brain barrier (BBB) impairment. Finally, the abnormal behavioral performance, aberrant vascular phenotype, and BBB breakdown defects in Plxnd1 knockout mice were restored following the inhibition of VEGF signaling during vascular remodeling. These findings demonstrate that Sema3E-Plexin-D1 signaling can promote functional recovery by downregulating VEGF signaling in the injured adult brain.

An Inhibitor of the Sodium-Hydrogen Exchanger-1 (NHE-1), Amiloride, Reduced Zinc Accumulation and Hippocampal Neuronal Death after Ischemia

Acidosis in the brain plays an important role in neuronal injury and is a common feature of several neurological diseases. It has been reported that the sodium–hydrogen exchanger-1 (NHE-1) is a key mediator of acidosis-induced neuronal injury. It modulates the concentration of intra- and extra-cellular sodium and hydrogen ions. During the ischemic state, excessive sodium ions enter neurons and inappropriately activate the sodium–calcium exchanger (NCX). Zinc can also enter neurons through voltage-gated calcium channels and NCX. Here, we tested the hypothesis that zinc enters the intracellular space through NCX and the subsequent zinc accumulation induces neuronal cell death after global cerebral ischemia (GCI). Thus, we conducted the present study to confirm whether inhibition of NHE-1 by amiloride attenuates zinc accumulation and subsequent hippocampus neuronal death following GCI. Mice were subjected to GCI by bilateral common carotid artery (BCCA) occlusion for 30 min, followed by restoration of blood flow and resuscitation. Amiloride (10 mg/kg, intraperitoneally (i.p.)) was immediately injected, which reduced zinc accumulation and neuronal death after GCI. Therefore, the present study demonstrates that amiloride attenuates GCI-induced neuronal injury, likely via the prevention of intracellular zinc accumulation. Consequently, we suggest that amiloride may have a high therapeutic potential for the prevention of GCI-induced neuronal death.

Determination of netrin-1 levels and its relationship with neurotoxicity in carbon monoxide poisoning

OBJECTIVE

The aim of the study was to assess netrin-1 levels in carbon monoxide (CO) poisoning to determine its relationship with poisoning severity and neurotoxicity.

METHODS

This is a cross-sectional prospective study. The patients older than 18 years with CO poisoning were included. The patients were categorized into two groups on the basis of neurological involvement. Both the patient and the control groups were sampled for netrin-1 at 0th hour, and the patient group only was sampled for netrin-1 at 4th hour.

RESULTS

A total of 84 patients and 50 healthy controls were enrolled. The median 0th hour netrin-1 level of the patient group (765.1 pg/mL (619.8-983.1) was significantly higher than the control group (484 pg/mL (376-1031.6)) ( p < 0.001). There was also a significant difference between the 0th hour and 4th hour netrin-1 (888.9 pg/mL (700.3-1175.5)) levels in the patient group ( p < 0.001).There was no significant statistical difference between patients with and without neurological involvement ( p = 0.62) and between those who underwent hyperbaric oxygen therapy (HBOT) and those who did not ( p = 0.76) with respect to 4th hour netrin-1 levels.

CONCLUSION

The significantly higher netrin-1 levels in patients with CO poisoning, suggests that netrin-1 is elevated as a stress marker. Although there is no significant difference in netrin-1 levels in patients with neurological impairment in CO poisonings, netrin-1 may show subclinically neurological effects. Hence, we believe that netrin-1 cannot be used as a marker of poisoning severity.

Arterialized collateral capillaries progress from nonreactive to capable of increasing perfusion in an ischemic arteriolar tree

OBJECTIVE

CCA, outward remodeling of capillaries that anastomose 2 arteriolar trees with different parent feed arteries, may represent a therapeutic target for patients who lack collaterals. ACCs can reperfuse an ischemic tree, but their functional capacity is unknown. Therefore, we determined whether ACCs mature into resistance vessels that regulate blood flow following arterial occlusion.

METHODS

We ligated the lateral spinotrapezius feed artery in Balb/C mice, which induces CCA. At days 7 and 21 following occlusion, we measured vasodilation of ACCs using intravital microscopy and blood flow in the ischemic tree using LSF. We determined the presence of ACCs and neurovascular alignment with immunofluorescence.

RESULTS

At day 7, ACCs do not vasodilate following muscle contraction and have reduced responses to endothelial- and smooth muscle-dependent agents. By day 21, ACCs exhibit normal vasodilation, accompanied by normalized increases in relative blood flow to the ischemic zone. Although functioning as resistance vessels by regulating blood flow, ACCs do not appear to be innervated.

CONCLUSIONS

ACCs mature into resistance vessels that regulate blood flow to the downstream tissue. Therefore, induction of mature ACCs may be a target for reducing ischemia in patients who lack collateral networks.

Marine Compound Xyloketal B as a Potential Drug Development Target for Neuroprotection

Xyloketal B is a natural compound isolated from the mangrove fungus, Xylaria sp. in the South China Sea. In the past decade, studies have shown that xyloketal B exhibits anti-oxidative, anti-inflammatory, and anti-apoptotic abilities and may serve as a treatment for ischemic stroke. Xyloketal B has been shown to interact with both neurons and residential microglial cells and regulate a number of proteins involved in the apoptotic events during ischemia. Such mechanisms include inhibition of specific NADPH oxidase subunits, upregulation of HO-1, increase of Bcl-1/Bax ratio, and downregulation of TLR4 receptor. Both in vitro and in vivo stroke models have validated its potential in preventing ischemia-induced neuronal cell death. This review summarizes our current understanding of the effects of xyloketal B in ischemic conditions. As stroke ranks second in the causes of mortality worldwide and still lacks effective treatment, it is necessary to seek novel therapeutic options. Understanding the role of xyloketal B in ischemic stroke could reveal a new aspect of stroke treatment.

Netrin-1 improves adipose-derived stem cell proliferation, migration, and treatment effect in type 2 diabetic mice with sciatic denervation

BACKGROUND

Diabetic peripheral neurovascular diseases (DPNVs) are complex, lacking effective treatment. Autologous/allogeneic transplantation of adipose-derived stem cells (ADSCs) is a promising strategy for DPNVs. Nonetheless, the transplanted ADSCs demonstrate unsatisfying viability, migration, adhesion, and differentiation in vivo, which reduce the treatment efficiency. Netrin-1 secreted as an axon guidance molecule and served as an angiogenic factor, demonstrating its ability in enhancing cell proliferation, migration, adhesion, and neovascularization.

METHODS

ADSCs acquired from adipose tissue were modified by Netrin-1 gene (NTN-1) using the adenovirus method (N-ADSCs) and proliferation, migration, adhesion, and apoptosis examined under high-glucose condition. The sciatic denervated mice (db/db) with type 2 diabetes mellitus (T2DM) were transplanted with N-ADSCs and treatment efficiency assessed based on the laser Doppler perfusion index, immunofluorescence, and histopathological assay. Also, the molecular mechanisms underlying Netrin-1-mediated proliferation, migration, adhesion, differentiation, proangiogenic capacity, and apoptosis of ADSCs were explored.

RESULTS

N-ADSCs improved the proliferation, migration, and adhesion and inhibited the apoptosis of ADSCs in vitro in the condition of high glucose. The N-ADSCs group demonstrated an elevated laser Doppler perfusion index in the ADSCs and control groups. N-ADSCs analyzed by immunofluorescence and histopathological staining demonstrated the distribution of the cells in the injected limb muscles, indicating chronic ischemia; capillaries and endothelium were formed by differentiation of N-ADSCs. The N-ADSCs group showed a significantly high density of the microvessels than the ADSCs group. The upregulation of AKT/PI3K/eNOS/P-38/NF-κB signaling pathways and secretion of multiple growth factors might explain the positive effects of Netrin-1 on ADSCs.

CONCLUSION

The overexpression of Netrin-1 in ADSCs improves proliferation, migration, and treatment effect in type 2 diabetic mice with sciatic denervation, which directs the clinical treatment of patients with DPNVs.

Netrin-1 Promotes Synaptic Formation and Axonal Regeneration via JNK1/c-Jun Pathway after the Middle Cerebral Artery Occlusion

As a secreted axon guidance molecule, Netrin-1 has been documented to be a neuroprotective factor, which can reduce infarct volume, promote angiogenesis and anti-apoptosis after stroke in rodents. However, its role in axonal regeneration and synaptic formation after cerebral ischemic injury, and the related underlying mechanisms remain blurred. In this study, we used Adeno-associated vectors carrying Netrin-1 gene (AAV-NT-1) to up-regulate the expression level of Netrin-1 in rats’ brain after middle cerebral artery occlusion (MCAO). We found that the up-regulated level of Netrin-1 and its receptor DCC promoted axonal regeneration and synaptic formation; the overexpression of Netrin-1 activated the JNK1 signaling pathway; these effects were partially reduced when JNK1 signaling pathway was inhibited by SP600125 (JNK specific inhibitor). Taken together, these findings suggest that Netrin-1 can facilitate the synaptic formation and axonal regeneration via the JNK1 signaling pathway after cerebral ischemia, thus promoting the recovery of neural functions.

Netrin as a Novel Biomarker and Its Therapeutic Implications in Diabetes Mellitus and Diabetes-Associated Complications

Diabetes is a multifactorial metabolic syndrome and is one of the shared long-lasting illnesses globally. It is linked to long-term microvascular and macrovascular complications that contribute to disability, compromised quality of life, and reduction in lifespan, which eventually leads to death. This disease is not only incurring significant economic burden but also adversely affects the patients, caregivers, communities, and the society at large. The interruption of diabetes progress and its complications is a primary focus of scientific communities. In spite of various diagnostic modalities for diabetes, there is a limited marker to investigate the risk and progress of its complications. Netrin has recently received more attention as a biomarker of diabetes and a broader range of long-term complication. Therefore, the impetus of this review is to exhaustively discuss the role of Netrin as a potential biomarker and its therapeutic implication in diabetes and diverse sets of microvascular and macrovascular complications of diabetes. It also discourses the possible mechanisms of Netrin for the said pharmacological effect for a better understanding of the development and progression of diabetes and its complications in relation to this protein. It enables protective measures to be applied at the subclinical stage and the responses to preventive or therapeutic measures to be scrutinized. Besides, it might also facilitate the appraisal of novel therapeutic options for diabetes and various complications through modifying the endogenous Netrin and provide surrogate endpoints for intervention.

The Role of Netrin-1 in Improving Functional Recovery through Autophagy Stimulation Following Spinal Cord Injury in Rats

Our previous findings indicated that treatment with Netrin-1 could improve functional recovery through the stimulation of autophagy, by activating the AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) signaling pathway in rats following spinal cord injury (SCI). However, the underlying mechanisms were not elucidated. The purpose of this study was to investigate the underlying mechanisms by which Netrin-1 promotes autophagy and improves functional recovery after SCI. Following controlled SCI in Sprague-Dawley rats, we observed that the autophagic flux in neurons was impaired, as reflected by the accumulation of light chain 3-II (LC3-II)-positive and LC3-positive autophagosomes (APs), accompanied by the accumulation of the autophagic substrate, Sequestosome 1 (SQSTM1; also known as p62). Our results showed that treatment with Netrin-1 increases the levels of the lysosomal protease cathepsin D (CTSD) and lysosomal-associated membrane protein 1 (LAMP1), through the regulation of the nuclear localization of Transcription factor EB (TFEB) via the AMPK/mTOR signaling pathway. In addition, this enhancement of lysosomal biogenesis correlated strongly with the restoration of autophagic flux, inhibition of neural apoptosis and improved functional recovery. Suppression of lysosomal biogenesis via the inhibition of the nuclear translocation of TFEB by Compound C abolished this restoration of autophagic flux and the functional recovery effects of Netrin-1 following SCI. Taken together, these results indicate that Netrin-1 enhances lysosomal biogenesis by regulating the nuclear translocation of TFEB via the AMPK/mTOR signaling pathway. Furthermore, the enhancement of lysosomal biogenesis by Netrin-1 following SCI promotes autophagic flux and improves functional recovery in rats. Thus, the regulation of lysosomal biogenesis by modulating the nuclear localization of TFEB might be a novel approach for the treatment of SCI.

Repulsive guidance molecule a suppresses angiogenesis after ischemia/reperfusion injury of middle cerebral artery occlusion in rats

Repulsive guidance molecule a (RGMa) has now emerged as a molecule with pleiotropic roles, including repulsion, adhesion, migration and differentiation in the nervous system. In this study, adult male Sprague-Dawley (SD) rats received 90-min middle cerebral artery occlusion (MCAO) to observe RGMa/neogenin expression sites after ischemia/reperfusion injury and changes in angiogenesis after treatment with RNA interference using RGMa-specific recombinant adenovirus rAd5-shRNA-RGMa (rAd-shRGMa). To clarify how RGMa mediates angiogenesis, the RGMa function-blocking peptide six fibronectin type III (6FNIII) was also administered, and corresponding changes in vascular endothelial growth factor (VEGF), angiopoietin-2 (Ang2), angiopoietin-1 (Ang1), and brain derived neurotrophic factor (BDNF) were determined by western blotting. Both RGMa and its receptor neogenin were expressed in neurons and vessel endothelial cells after ischemia/reperfusion injury, and angiogenesis, coupled with functional recovery, was enhanced after RNA interference against RGMa compared with the vehicle groups. VEGF, Ang2, Ang1 and BDNF expression levels were significantly increased after intervention with rAd-shRGMa or 6FNIII. Thus, RGMa might suppress angiogenesis via VEGF, Ang2, Ang1 and BDNF after cerebral ischemia/reperfusion injury, which has therapeutic potential by reducing these endogenous detrimental mechanisms.

Netrin-1 promotes glioma growth by activating NF-κB via UNC5A

Gliomas, a common type of brain tumor, are characterized by aggressive infiltration, making it difficultly to cure by surgery. Netrin-1, an extracellular guidance cue critical for neuronal axon path-finding, has been reported to play an important role in cell invasion and migration in several types of cancers. However, the role of netrin-1 in glioma remains largely unknown. Here, we provide evidence suggested that Netrin-1 has a critical role in glioma growth. We found that netrin-1 was significantly increased in glioma samples and positively correlated with cell proliferation, tumor grade and malignancy. Netrin-1 knockdown reduced cell proliferation and attenuated tumor growth in a xenograft mouse model. Further studies found that netrin-1 induced NF-κB p65^ser536 phosphorylation and c-Myc expression in vitro and in vivo. Interestingly, activation of NF-κB by netrin-1 was dependent on UNC5A receptor, because suppression of UNC5A significantly inhibited NF-κB p65^ser536 phosphorylation, c-Myc up-regulation and reduced cell proliferation. Taken together, these results suggested netrin-1 promotes glioma cell proliferation by activating NF-κB signaling via UNC5A, netrin-1 may be a potential therapeutic target for the treatment of glioma.

Tumor angiogenesis revisited: Regulators and clinical implications

Since Judah Folkman hypothesized in 1971 that angiogenesis is required for solid tumor growth, numerous studies have been conducted to unravel the angiogenesis process, analyze its role in primary tumor growth, metastasis and angiogenic diseases, and to develop inhibitors of proangiogenic factors. These studies have led in 2004 to the approval of the first antiangiogenic agent (bevacizumab, a humanized antibody targeting vascular endothelial growth factor) for the treatment of patients with metastatic colorectal cancer. This approval launched great expectations for the use of antiangiogenic therapy for malignant diseases. However, these expectations have not been met and, as knowledge of blood vessel formation accumulates, many of the original paradigms no longer hold. Therefore, the regulators and clinical implications of angiogenesis need to be revisited. In this review, we discuss recently identified angiogenesis mediators and pathways, new concepts that have emerged over the past 10 years, tumor resistance and toxicity associated with the use of currently available antiangiogenic treatment and potentially new targets and/or approaches for malignant and nonmalignant neovascular diseases.

Netrin-1 acts as a non-canonical angiogenic factor produced by human Wharton's jelly mesenchymal stem cells (WJ-MSC)

BACKGROUND

Angiogenesis, the process in which new blood vessels are formed from preexisting ones, is highly dependent on the presence of classical angiogenic factors. Recent evidence suggests that axonal guidance proteins and their receptors can also act as angiogenic regulators. Netrin, a family of laminin-like proteins, specifically Netrin-1 and 4, act via DCC/Neogenin-1 and UNC5 class of receptors to promote or inhibit angiogenesis, depending on the physiological context.

METHODS

Mesenchymal stem cells secrete a broad set of classical angiogenic factors. However, little is known about the expression of non-canonical angiogenic factors such as Netrin-1. The aim was to characterize the possible secretion of Netrin ligands by Wharton's jelly-derived mesenchymal stem cells (WJ-MSC). We evaluated if Netrin-1 presence in the conditioned media from these cells was capable of inducing angiogenesis both in vitro and in vivo, using human umbilical vein endothelial cells (HUVEC) and chicken chorioallantoic membrane (CAM), respectively. In addition, we investigated if the RhoA/ROCK pathway is responsible for the integration of Netrin signaling to control vessel formation.

RESULTS

The paracrine angiogenic effect of the WJ-MSC-conditioned media is mediated at least in part by Netrin-1 given that pharmacological blockage of Netrin-1 in WJ-MSC resulted in diminished angiogenesis on HUVEC. When HUVEC were stimulated with exogenous Netrin-1 assayed at physiological concentrations (10-200 ng/mL), endothelial vascular migration occurred in a concentration-dependent manner. In line with our determination of Netrin-1 present in WJ-MSC-conditioned media we were able to obtain endothelial tubule formation even in the pg/mL range. Through CAM assays we validated that WJ-MSC-secreted Netrin-1 promotes an increased angiogenesis in vivo. Netrin-1, secreted by WJ-MSC, might mediate its angiogenic effect through specific cell surface receptors on the endothelium, such as UNC5b and/or integrin α6β1, expressed in HUVEC. However, the angiogenic response of Netrin-1 seems not to be mediated through the RhoA/ROCK pathway.

CONCLUSIONS

Thus, here we show that stromal production of Netrin-1 is a critical component of the vascular regulatory machinery. This signaling event may have deep implications in the modulation of several processes related to a number of diseases where angiogenesis plays a key role in vascular homeostasis.

Netrin-1 Improves Functional Recovery through Autophagy Regulation by Activating the AMPK/mTOR Signaling Pathway in Rats with Spinal Cord Injury

Autophagy is an process for the degradation of cytoplasmic aggregated proteins and damaged organelles and plays an important role in the development of SCI. In this study, we investigated the therapeutic effect of Netrin-1 and its potential mechanism for autophagy regulation after SCI. A rat model of SCI was established and used for analysis. Results showed that administration of Netrin-1 not only significantly enhanced the phosphorylation of AMP-activated protein kinase (AMPK) but also reduced the phosphorylation of mammalian target of rapamycin (mTOR) and P70S6K. In addition, the expression of Beclin-1 and the ratio of the light-chain 3B-II (LC3B-II)/LC3B-I in the injured spinal cord significantly increased in Netrin-1 group than those in SCI group. Moreover, the ratio of apoptotic neurons in the anterior horn of the spinal cord and the cavity area of spinal cord significantly decreased in Netrin-1 group compared with those in SCI group. In addition, Netrin-1 not only preserved motor neurons but also significantly improved motor fuction of injured rats. These results suggest that Netrin-1 improved functional recovery through autophagy stimulation by activating the AMPK/mTOR signaling pathway in rats with SCI. Thus, Netrin-1 treatment could be a novel therapeutic strategy for SCI.

Netrin-1 overexpression improves neurobehavioral outcomes and reduces infarct size via inhibition of the notch1 pathway following experimental stroke

Stroke is a leading cause of morbidity and mortality worldwide. Administration of Netrin-1 during the peri-infarct period has been shown to decrease infarct size in rats; however, the underlying mechanism is unclear. We addressed this question in the present study by inducing stroke in rats via middle cerebral artery occlusion (MCAO), and evaluating the effects of Netrin-1 treatment by neurobehavioral testing, immunocytochemistry, and western blotting. Netrin-1 overexpression increased neurobehavioral test scores and reduced cerebral infarct volume following MCAO via inhibition of the Notch1 signaling pathway. These results demonstrate that early administration of Netrin-1 can is an effective therapeutic approach for improving outcome after stroke. © 2017 Wiley Periodicals, Inc.

Phosphofructokinase-1 Negatively Regulates Neurogenesis from Neural Stem Cells

Phosphofructokinase-1 (PFK-1), a major regulatory glycolytic enzyme, has been implicated in the functions of astrocytes and neurons. Here, we report that PFK-1 negatively regulates neurogenesis from neural stem cells (NSCs) by targeting pro-neural transcriptional factors. Using in vitro assays, we found that PFK-1 knockdown enhanced, and PFK-1 overexpression inhibited the neuronal differentiation of NSCs, which was consistent with the findings from NSCs subjected to 5 h of hypoxia. Meanwhile, the neurogenesis induced by PFK-1 knockdown was attributed to the increased proliferation of neural progenitors and the commitment of NSCs to the neuronal lineage. Similarly, in vivo knockdown of PFK-1 also increased neurogenesis in the dentate gyrus of the hippocampus. Finally, we demonstrated that the neurogenesis mediated by PFK-1 was likely achieved by targeting mammalian achaete-scute homologue-1 (Mash 1), neuronal differentiation factor (NeuroD), and sex-determining region Y (SRY)-related HMG box 2 (Sox2). All together, our results reveal PFK-1 as an important regulator of neurogenesis.

Circulating microRNA 132-3p and 324-3p Profiles in Patients after Acute Aneurysmal Subarachnoid Hemorrhage

Background

Aneurysmal subarachnoid hemorrhage (SAH) is a highly morbid and fatal condition with high rate of cognitive impairment and negative impact in quality of life among survivors. Delayed cerebral infarction (DCI) is one the major factors for these negative outcomes. In this study we compared the circulating microRNA profiles of SAH patients and healthy individuals, and the circulating microRNA profiles of SAH patients with and without DCI.

Methods

Peripheral blood samples on Day 7 after the onset of SAH were subjected to microarray analysis with Affymetrix miRNA 3.0 array and quantitative PCR analysis. SAH patients with (N = 20) and without DCI (N = 20) and Healthy controls (N = 20) were included for analyses.

Results

We demonstrated that 99 miRNAs were found to be dysregulated in the SAH patient group with DCI. 81 miRNAs were upregulated and 18 were downregulated. Findings from KEGG pathway analysis showed that miRNAs and target genes for axon guidance and TGF-beta signaling were involved, implying that the resulted differential miRNA expression pattern reflect the results of SAH instead of etiology of the disease. miR-132-3p and miR-324-3p showed distinctive upregulations in qPCR [miR-132: 9.5 fold (95%CI: 2.3 to 16.7) in DCI group and 3.4 fold (95%CI: 1.0 to 5.8) in Non-DCI group; miR-324: 4924 fold (95%CI: 2620 to 7228) in DCI group and 4545 fold (95%CI: 2408 to 6683) in non-DCI group]. However, there were no significant differences in fold changes between SAH patients with and without DCI [fold change ratios (mean+/-SD): 2.7+/-4.2 and 1.1+/-1.1 for miRNA-132 and miRNA-324].

Conclusion

Our study demonstrated that as compared to healthy control, miR-132 and miR-324 showed a upregulation in both SAH DCI and Non-DCI groups. However, the differences between the SAH DCI and non-DCI groups were not statistically significant.

Microarray Profiling and Co-Expression Network Analysis of LncRNAs and mRNAs in Neonatal Rats Following Hypoxic-ischemic Brain Damage

Long noncoding RNAs (lncRNAs) play critical roles in cellular homeostasis. However, little is known about their effect in developing rat brains with hypoxic-ischemic brain damage (HIBD). To explore the expression and function of lncRNA in HIBD, we analyzed the expression profiles of lncRNAs in hypoxic-ischemic (HI) brains and sham control using microarray analysis. The results showed a remarkable difference in lncRNA between HI and sham brains. A total of 322 lncRNAs were found to be differentially expressed in HI brains, compared to sham control. Among these, BC088414 was one of the most significantly urpregulated lncRNAs. In addition, 375 coding genes were differentially expressed between HI brains and sham control. Pathway and gene ontology analysis indicated that the upregulated coding genes mostly involved in wounding, inflammation and defense, whereas the downregulated transcripts were largely associated with neurogenesis and repair. Moreover, coding non-coding co-expression network analysis showed that the BC088414 lncRNA expression was correlated with apoptosis-related genes, including Casp6 and Adrb2. Silencing of lncRNA BC088414 in PC12 cells caused reduced mRNA level of Casp6 and Adrb2, decreased cell apoptosis and increased cell proliferation. These results suggested lncRNA might participate in the pathogenesis of HIBD via regulating coding genes.