Hypothalamic supramammillary neurons that project to the medial septum modulate wakefulness in mice.

The hypothalamic supramammillary nucleus (SuM) plays a crucial role in controlling wakefulness, but the downstream target regions participating in this control process remain unknown. Here, using circuit-specific fiber photometry and single-neuron electrophysiology together with electroencephalogram, electromyogram and behavioral recordings, we find that approximately half of SuM neurons that project to the medial septum (MS) are wake-active. Optogenetic stimulation of axonal terminals of SuM-MS projection induces a rapid and reliable transition to wakefulness from non-rapid-eye movement or rapid-eye movement sleep, and chemogenetic activation of SuMMS projecting neurons significantly increases wakefulness time and prolongs latency to sleep. Consistently, chemogenetically inhibiting these neurons significantly reduces wakefulness time and latency to sleep. Therefore, these results identify the MS as a functional downstream target of SuM and provide evidence for the modulation of wakefulness by this hypothalamic-septal projection.

Traumatic events in childhood and adulthood in a diverse-ancestry sample and their role in bipolar disorder.

We examined the presence of adverse events in both childhood and adulthood and the prevalence of PTSD in individuals with Bipolar Disorder (BD). There were 191 adults diagnosed with BD Type I and 924 controls, of predominantly African Ancestry (AA). All were administered the GPC-Screening Tool and the BD group the DIPAD. In addition Childhood adversities were measured using the ACE (from 0 to 10), about traumatic events before age 18 and lifetime adversities were measured with 15 questions adapted from the Study of Addiction: Genetics and Environment (A-SAGE (from 0 to 15) for all cases and controls. Probable PTSD (pPTSD) was measured with 4 questions on the GPC screener. Sum scores were calculated for the ACE and A-SAGE by tallying positive responses. Odd Ratios (OR) were used to measure the association between BD and Controls exposure to adversity. BD was associated with a significantly higher mean ACE score and A-SAGE score compared to controls. There was a significantly higher prevalence of pPTSD in the BD (54.5%) versus Controls (6.6%) as well. Greater OR's were seen in the BD compared to Controls for each ACE question (p<0.05). Results were similar for A-SAGE. Limitations include possible recall bias, and missing data.

Optrode recording of an entorhinal-cortical circuit in freely moving mice.

The deep layers of medial entorhinal cortex (MEC) are considered a crucial station for spatial cognition and memory. The deep sublayer Va of MEC (MECVa) serves as the output stage of the entorhinal-hippocampal system and sends extensive projections to brain cortical areas. However, the functional heterogeneity of these efferent neurons in MECVa is poorly understood, due to the difficulty of performing single-neuron activity recording from the narrow band of cell population while the animals are behaving. In the current study, we combined multi-electrode electrophysiological recording and optical stimulation to record cortical-projecting MECVa neurons at single-neuron resolution in freely moving mice. First, injection of a viral Cre-LoxP system was used to express channelrhodopsin-2 specifically in MECVa neurons that project to the medial part of the secondary visual cortex (V2M-projecting MECVa neurons). Then, a lightweight, self-made optrode was implanted into MECVa to identify the V2M-projecting MECVa neurons and to enable single-neuron activity recordings in mice performing the open field test and 8-arm radial maze. Our results demonstrate that optrode approach is an accessible and reliable method for single-neuron recording of V2M-projecting MECVa neurons in freely moving mice, paving the way for future circuit studies designed to characterize the activity of MECVa neurons during specific tasks.

REM sleep-active hypothalamic neurons may contribute to hippocampal social-memory consolidation.

The hippocampal CA2 region plays a key role in social memory. The encoding of such memory involves afferent activity from the hypothalamic supramammillary nucleus (SuM) to CA2. However, the neuronal circuits required for consolidation of freshly encoded social memory remain unknown. Here, we used circuit-specific optical and single-cell electrophysiological recordings in mice to explore the role of sleep in social memory consolidation and its underlying circuit mechanism. We found that SuM neurons projecting to CA2 were highly active during rapid-eye-movement (REM) sleep but not during non-REM sleep or quiet wakefulness. REM-sleep-selective optogenetic silencing of these neurons impaired social memory. By contrast, the silencing of another group of REM sleep-active SuM neurons that projects to the dentate gyrus had no effect on social memory. Therefore, we provide causal evidence that the REM sleep-active hypothalamic neurons that project to CA2 are specifically required for the consolidation of social memory.

Simvastatin Upregulates Lipoxin A4 and Accelerates Neuroinflammation Resolution After Intracerebral Hemorrhage.

BACKGROUND: Previous studies have demonstrated that statins can relieve inflammatory brain injury after intracerebral hemorrhage (ICH), but the mechanisms remain poorly characterized. This study aims to test whether simvastatin exerts an anti-inflammatory effect by regulating the proresolving mediators. METHODS: First, male Sprague-Dawley rats had an injection of 200 µL autologous blood. Then, rats were randomly divided into groups treated with simvastatin (i.p. 2 mg/kg) or vehicle. Next, all rats underwent pro-resolving mediator lipoxin A4 (LXA4) level detection, flow cytometric, immunofluorescence, brain edema measurement, neurological scoring and western blot analysis. RESULTS: We found that simvastatin significantly increased the plasma level of LXA4, an endogenous formyl-peptide receptor 2 (FPR2) agonist, in the early stage of ICH. Consistent with the effect of simvastatin, exogenous LXA4 administration also promoted apoptosis of the circulating neutrophils, reduced neutrophils brain infiltration, and ameliorated inflammatory brain injury after ICH. In addition, similar to simvastatin, exogenous LXA4 markedly decreased the level of phosphorylated p38 mitogen-activated protein kinase (MAPK) and the apoptosis-related proteins myeloid cell leukemia 1(Mcl-1)/Bax ratio (a decreased ratio represents the induction of apoptosis) in circulating neutrophils isolated from ICH rats. Notably, all of the aforementioned effects of simvastatin on ICH were significantly abolished by Boc-2, a selective antagonist of FPR2. Moreover, simvastatin led to a similar Mcl-1/Bax ratio reduction as SB203580 (a p38 MAPK inhibitor), but it was abolished by P79350 (a p38 MAPK agonist). CONCLUSION: Collectively, these results suggest that simvastatin ameliorates ICH-mediated inflammatory brain injury, possibly by upregulating the level of pro-resolving mediator LXA4 and further stimulating the FPR2/p38 MAPK signaling pathway.

Biomass distribution pattern and stoichiometric characteristics in main shrub ecosystems in Central Yunnan, China.

BACKGROUND: With the exacerbating effects of the global climate change and the more and more attention to the study of plant carbon sink, an increasing number of researches on plant carbon sinks has grown. Although many studies exist on shrub vegetation, soil and litters, most studies focus on the community structure, biomass, surface soil of single plant and shrub layer vegetation, and lack the studies which included the potential relationships between climate change and ecological stoichiometric elements, comprehensive research on main species, even herb and litter layer. In order to provide relevant theoretical basis and data support, it is necessary to take the main terrestrial shrub ecosystem in Central Yunnan as the starting point to analyze and explore its carbon sink distribution characteristics, formation causes, the correlation between climatic factors (temperature and precipitation) and stoichiometric elements, which from community and species levels. METHODS: Plants which originated from 12 main shrub species, litter and soil samples which collected in 69 plots were from 23 plots (Q1-Q23) of 11 cities (countries) in the central Yunnan, China. The biomass and carbon density distribution pattern of each shrub ecosystem and the potential correlations with main climate factors was explored and identified. Some indexes were analyzed such as biomass and carbon density of each part of the shrub ecosystem distribution pattern, correlation, significant changes, formation reasons with the mean value (±standard deviation: SD). Through the redundancy analysis(RDA) of carbon (c), nitrogen (n), phosphorus (P) and main climate factors (precipitation and temperature), the distribution pattern of stoichiometric elements in shrub ecosystem can be judged. RESULTS: (1) The above-ground biomass (AGB), under-ground biomass (UGB) and root-shoot ratio (R/S) were between 1.13-2.03 t/hm2, 0.62-1.49 t/hm2, and 0.38-0.84, the carbon element was distributed in herb layer under-ground part and rhizomes of the shrub layer mostly. (2) The fitting slope of AGB and UGB of shrub communities and species was in accordance with the allometric distribution growth relationship, the R/S of shrubs was smaller than other vegetation types. Mean annual temperature (MAT) and mean annual precipitation (MAP) are not the main factors which affect the biomass and R/S. (3) The contents of C, N and P elements in leaves were significantly higher than other parts in shrub layer. P in shrub layer above-ground part is much higher than under-ground part. The surface soil layer has the highest C content, and decreased with the depth, so as the impact of vegetation and litter on the content of soil elements. Both of the correlation of MAT with N content of leaf, C/N of stem, the correlation of MAP with C content, C/N of soil is the greatest.

MicroRNA-455-5p/CPEB1 pathway mediates Aß-related learning and memory deficits in a mouse model of Alzheimer's disease.

Alzheimer's disease (AD), a common neurodegenerative disease, is the main cause of dementia, with cognitive decline as the core symptom observed during diagnosis. Synaptic loss may be the main cause of early cognitive dysfunction in AD, but the detailed mechanism is still unclear. In this study, we investigated the role of abnormal miR-455-5p/CPEB1 pathway in AD mouse model. We found that miR-455-5p was upregulated, while its downstream target, cytoplasmic polyadenylation element-binding 1 (CPEB1), was downregulated in the hippocampus of APP/PS1 mice at the age of 9 m. Abnormal miR-455-5p/CPEB1 pathway mediated cognitive deficits in APP/PS1 mice through suppressing α-Amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor expressions. And miR-455-5p suppression, CPEB1 overexpression or application of a peptide disrupting the miR-455-5p/CPEB1 interaction in CA1 of APP/PS1 mice rescued AD-like phenotypes in mice, including deficits in synaptic plasticity and memory. In conclusion, our results indicated that miRNA-455-5p/CPEB1 pathway mediated synaptic and memory deficits in Alzheimer's Disease through targeting on AMPARs, providing a potential therapeutic strategy for AD.

Glibenclamide Attenuates Neuroinflammation and Promotes Neurological Recovery After Intracerebral Hemorrhage in Aged Rats.

Intracerebral hemorrhage (ICH) is a common disease in the elderly population. Inflammation following ICH plays a detrimental role in secondary brain injury, which is associated with a poor prognosis of patients with ICH, and no efficient pharmacological preventions are available. Here, we investigated the effects of glibenclamide (GLC) on neuroinflammation in an autoblood-induced aged rat (18 months old) model of ICH. Rats were randomized into the sham, vehicle, and GLC groups. First, we investigated the expression level of sulfonylurea receptor 1 (Sur1) surrounding the hematoma after ICH. Then, neurological scores were calculated, and water maze tests, brain water content analysis, western blotting, and immunofluorescence assays were implemented to detect the neuroprotective effect of GLC. The expression of the Sur1-Trpm4 channel was significantly increased in the perihematomal tissue following ICH in aged rats. The GLC administration effectively reduced brain edema and improved neurofunction deficits following ICH. In addition, GLC increased the expression of brain-derived neurotrophic factors and decreased the expression of proinflammatory factors [tumor necrosis factor (TNF)-α,interleukin (IL)-1, and IL-6]. Moreover, GLC markedly reduced Ikappa-B (IκB) kinase (IKK) expression in microglia and nuclear factor (NF)-κB-P65 levels in perihematomal tissue. GLC ameliorated ICH-induced neuroinflammation and improved neurological outcomes in aged rats. In part, GLC may exert these effects by regulating the NF-κB signaling pathway through the Sur1-Trpm4 channel.

uPA alleviates kaolin-induced hydrocephalus by promoting the release and activation of hepatocyte growth factor in rats.

Urokinase-type plasminogen activator (uPA) was demonstrated to alleviate kaolin-induced communicating hydrocephalus via inhibiting subarachnoid space fibrosis, but the exact mechanism remains elusive. Thus, this study was designed to investigate if hepatocyte growth factor (HGF), which plays a vital role in uPA-triggered inhibiting of fibrosis in multiple systems, is involved in this process in hydrocephalus. There were 2 parts in this study. First, hydrocephalus was induced in rats by basal cistern injection of kaolin. Then rats were treated with saline or uPA and brain tissue and CSF were collected for Western blot and enzyme-linked immuno sorbent assay (ELISA) four days later. Second, kaolin-induced hydrocephalus rats were treated with saline, uPA, uPA + PHA665752 (antagonist of HGF) or PHA665752. Some animals received MRI four weeks later and brains were used for immunofluorescence. The others were euthanized four days later for ELISA. Both levels of total and activated HGF in the CSF was increased after uPA injections, but related mRNA expression of HGF showed no statistical significance when compared with the control group. Further, the effects of uPA that alleviating ventricular enlargement, subarachnoid fibrosis and reactive astrocytosis were partially reversed by PHA665752. Moreover, PHA665752 partially abolished uPA-induced reduction of transforming growth factor- ß1(TGF- ß1) level in CSF. Our data suggest that uPA effectively inhibited subarachnoid fibrosis and restricted the development of communicating hydrocephalus in rats in part by promoting HGF release and activation, which may further regulate the TGF-ß1 expression in CSF.

Quantitative Iron Neuroimaging Can Be Used to Assess the Effects of Minocycline in an Intracerebral Hemorrhage Minipig Model.

Iron-mediated toxicity is a key factor causing brain injury after intracerebral hemorrhage (ICH). This study was performed to investigate the noninvasive neuroimaging method for quantifying brain iron content using a minipig ICH model and assess the effects of minocycline treatment on ICH-induced iron overload and brain injury. The minipig ICH model was established by injecting 2 ml of autologous blood into the right basal ganglia, which were then subjected to the treatments of minocycline and vehicle. Furthermore, the quantitative susceptibility mapping (QSM) was used to quantify iron content, and diffusion tensor imaging (DTI) was performed to evaluate white matter tract. Additionally, we also performed immunohistochemistry, Western blot, iron assay, Perl's staining, brain water content, and neurological score to evaluate the iron overload and brain injury. Interestingly, we found that the ICH-induced iron overload could be accurately quantified by the QSM. Moreover, the minocycline was quite beneficial for protecting brain injury by reducing the lesion volume and brain edema, preventing brain iron accumulation, downsizing ventricle enlargement, and alleviating white matter injury and neurological deficits. In summary, we suggest that the QSM be an accurate and noninvasive method for quantifying brain iron level, and the minocycline may be a promising therapeutic agent for patients with ICH.

Edaravone Reduces Iron-Mediated Hydrocephalus and Behavioral Disorder in Rat by Activating the Nrf2/HO-1 Pathway.

Our previous studies have demonstrated that hemorrhage-derived iron has a key role in causing brain injury after intraventricular hemorrhage (IVH). Based on this finding, we hypothesized that edaravone, a free-radical scavenger, has the potential to alleviate hydrocephalus and neurological deficits post-IVH by suppressing iron-induced oxidative stress. Thus, this study aimed to investigate the efficacy of edaravone for rats with FeCl3 injection, as well as to explore the related molecular mechanism. An experimental model was established in adult male Sprague-Dawley rats via FeCl3 injection into the right lateral ventricle. Edaravone or vehicle was administered immediately, 1 day and 2 days after intraventricular injection. Brain water content, magnetic resonance imaging, neurological score, oxidative stress assays, Western blot analysis, and electron microscopy were employed to evaluate brain injury in these rats. Intraventricular injection of FeCl3 induced brain edema, ventricular dilation, and neurobehavioral disorder in rats. Edaravone treatment significantly attenuated the above symptoms, reduced ependymal cilia and neuron damage, and inhibited oxidative stress (elevated levels of an antioxidant, superoxide dismutase; decreased levels of an oxidant, malondialdehyde). Moreover, edaravone administration effectively activated the Nrf2/HO-1 signaling pathway in rat brain following FeCl3 injection. These results showed that edaravone treatment alleviated brain edema, ventricular expansion, and neurological disorder after FeCl3 injection. The possible mechanism is by protecting ependymal cilia and neurons from oxidative stress injury and activating the Nrf2/HO-1 signaling pathway. These results provide further experimental evidence for edaravone application in the treatment of IVH.

Epothilone B Benefits Nigrostriatal Pathway Recovery by Promoting Microtubule Stabilization After Intracerebral Hemorrhage.

BACKGROUND: Many previous clinical studies have demonstrated that the nigrostriatal pathway, which plays a vital role in movement adjustment, is significantly impaired after stroke, according to medical imaging and autopsies. However, the basic pathomorphological changes have been poorly investigated to date. This study was designed to explore the pathomorphological changes, mechanism, and therapeutic method of nigrostriatal impairment after intracerebral hemorrhage (ICH). METHODS AND RESULTS: Intrastriatal injection of autologous blood or microtubule depolymerization reagent nocodazole was performed to mimic the pathology of ICH in C57/BL6 mice. Immunofluorescence, Western blotting, electron microscopy, functional behavioral tests, and anterograde and retrograde neural circuit tracking techniques were used in these mice. The data showed that the number of dopamine neurons and the dopamine concentration were severely decreased and that fine motor function was impaired after ICH. Microtubule depolymerization was the main contributor to the loss of dopamine neurons and to motor function deficits after ICH, as was also proven by intrastriatal injection of nocodazole. Moreover, administration of the microtubule stabilizer epothilone B (1.5 mg/kg) improved the integrity of the nigrostriatal pathway neural circuit, increased the number of dopamine neurons (4598±896 versus 3125±355; P=0.034) and the dopamine concentration (4.28±0.99 versus 3.08±0.75 ng/mg; P=0.041), and enhanced fine motor functional recovery associated with increased acetylated α-tubulin expression to maintain microtubule stabilization after ICH. CONCLUSIONS: Our results clarified the pathomorphological changes of the nigrostriatal pathway after ICH and found that epothilone B helped alleviate nigrostriatal pathway injury after ICH, associated with promoting α-tubulin acetylation to maintain microtubule stabilization, thus facilitating motor recovery.

Simvastatin accelerates hematoma resolution after intracerebral hemorrhage in a PPARγ-dependent manner.

To date, the neuroprotective effects of statins on intracerebral hemorrhage (ICH) are not well established. This study explored the effect and potential mechanism of simvastatin treatment on ICH. In the present study, the effects of simvastatin on hematoma absorption, neurological outcome, CD36 expression and microglia polarization were examined in rat model of ICH model. In the meantime, inhibitory effect of PPARγ inhibitor GW9662 was investigated following ICH. Additionally, the effect of simvastatin on PPARγ activation was also investigated in rat ICH model and primary microglia culture. Much more, the role of PPARγ and CD36 in simvastatin-mediated erythrocyte phagocytosis was also detected by using in vivo or in vitro phagocytosis models, respectively. After ICH, simvastatin promoted hematoma absorption and improved neurological outcome after ICH while upregulating CD36 expression and facilitating M2 phenotype polarization in perihematomal microglia. In addition, simvastatin increased PPARγ activation and reinforced microglia-induced erythrocyte phagocytosis in vivo and in vitro. All above effects of simvastatin were abolished by PPARγ inhibitor GW9662. In conclusion, our data suggested that simvastatin could enhance hematoma clearance and attenuate neurological deficits possibly by activating PPARγ.

Simvastatin Reduces Neutrophils Infiltration Into Brain Parenchyma After Intracerebral Hemorrhage via Regulating Peripheral Neutrophils Apoptosis.

Statins, known for their lipid-lowering effects, also have immunomodulatory properties. This study aims to examine whether systematic simvastatin administration could decrease polymorphonuclear neutrophils (PMNs) infiltration into brain tissue, as well as alleviate neuroinflammation in a rat model of intracerebral hemorrhage (ICH). The ICH model was induced in adult male Sprague-Dawley rats by an injection of autologous blood. Animals randomly received simvastatin (i.p. 2 mg/kg) or vehicle daily from 5 days before ICH until sacrificed. Routine blood counts, brain water content, neurological scoring, immunofluorescence and RT-PCR were conducted to evaluate the anti-inflammatory effect of simvastatin following ICH. Furthermore, flow cytometric and western blotting analysis were implemented for elucidating the mechanisms involved in simvastatin-induced reduction of neutrophil brain-invading. Elevated PMNs count and neutrophil-to-lymphocyte ratio in circulation were detected in rat model of ICH, which was reversed by using simvastatin. Simvastatin effectively alleviated PMNs infiltration and proinflammatory factors release in perihematomal area, as well as attenuated ICH-induced brain edema and neurological deficits. Simvastatin significantly downregulated the expression of antiapoptotic protein-Mcl-1 while increased the level of proapoptotic protein-Bax and cleaved caspase 3 in PMNs. Simvastatin treatment significantly alleviated PMNs brain-infiltrating and subsequent neuroinflammatory reaction after ICH, in part by accelerating peripheral PMNs apoptosis through disorganized the expression of apoptotic related proteins. Our data provided new evidence for simvastatin application on patients with ICH.

5-HT1a activation in PO/AH area induces therapeutic hypothermia in a rat model of intracerebral hemorrhage.

Therapeutic hypothermia is widely applied as a neuroprotective measure on intracerebral hemorrhage (ICH). However, several clinical trials regarding physical hypothermia encountered successive failures because of its side-effects in recent years. Increasing evidences indicate that chemical hypothermia that targets hypothalamic 5-HT1a has potential to down-regulate temperature set point without major side-effects. Thus, this study examined the efficacy and safety of 5-HT1a stimulation in PO/AH area for treating ICH rats. First, the relationship between head temperature and clinical outcomes was investigated in ICH patients and rat models, respectively. Second, the expression and distribution of 5-HT1a receptor in PO/AH area was explored by using whole-cell patch and confocal microscopy. In the meantime, the whole-cell patch was subsequently applied to investigate the involvement of 5-HT1a receptors in temperature regulation. Third, we compared the efficacy between traditional PH and 5-HT1a activation-induced hypothermia for ICH rats. Our data showed that more severe perihematomal edema (PHE) and neurological deficits was associated with increased head temperature following ICH. 5-HT1a receptor was located on warm-sensitive neurons in PO/AH area and 8-OH-DPAT (5-HT1a receptor agonist) significantly enhanced the firing rate of warm-sensitive neurons. 8-OH-DPAT treatment provided a steadier reduction in brain temperature without a withdrawal rebound, which also exhibited a superior neuroprotective effect on ICH-induced neurological dysfunction, white matter injury and BBB damage compared with physical hypothermia. These findings suggest that chemical hypothermia targeting 5-HT1a receptor in PO/AH area could act as a novel therapeutic manner against ICH, which may provide a breakthrough for therapeutic hypothermia.

Flexible electrochemical biosensors based on graphene nanowalls for the real-time measurement of lactate.

We demonstrate a flexible biosensor for lactate detection based on l-lactate oxidase immobilized by chitosan film cross-linked with glutaraldehyde on the surface of a graphene nanowall (GNW) electrode. The oxygen-plasma technique was developed to enhance the wettability of the GNWs, and the strength of the sensor's oxidation response depended on the concentration of lactate. First, in order to eliminate interference from other substances, biosensors were primarily tested in deionized water and displayed good electrochemical reversibility at different scan rates (20-100 mV s-1), a large index range (1.0 µM to 10.0 mM) and a low detection limit (1.0 µM) for lactate. Next, these sensors were further examined in phosphate buffer solution (to mimick human body fluids), and still exhibited high sensitivity, stability and flexibility. These results show that the GNW-based lactate biosensors possess important potential for application in clinical analysis, sports medicine and the food industry.

Post-hemorrhagic hydrocephalus: Recent advances and new therapeutic insights.

Post-hemorrhagic hydrocephalus (PHH), also referred to as progressive ventricular dilatation, is caused by disturbances in cerebrospinal fluid (CSF) flow or absorption following hemorrhage in the brain. As one of the most serious complications of neonatal/adult intraventricular hemorrhage (IVH), subarachnoid hemorrhage (SAH), and traumatic brain injury (TBI), PHH is associated with increased morbidity and disability of these events. Common sequelae of PHH include neurocognitive impairment, motor dysfunction, and growth impairment. Non-surgical measures to reduce increased intracranial pressure (ICP) in PHH have shown little success and most patients will ultimately require surgical management, such as external ventricular drainage and shunting which mostly by inserting a CSF drainage shunt. Unfortunately, shunt complications are common and the optimum time for intervention is unclear. To date, there remains no comprehensive strategy for PHH management and it becomes imperative that to explore new therapeutic targets and methods for PHH. Over past decades, increasing evidence have indicated that hemorrhage-derived blood and subsequent metabolic products may play a key role in the development of IVH-, SAH- and TBI-associated PHH. Several intervention strategies have recently been evaluated and cross-referenced. In this review, we summarized and discussed the common aspects of hydrocephalus following IVH, SAH and TBI, relevant experimental animal models, clinical translation of in vivo experiments, and potential preventive and therapeutic targets for PHH.

A selective CB2R agonist (JWH133) restores neuronal circuit after Germinal Matrix Hemorrhage in the preterm via CX3CR1+ microglia.

Microglia play dual roles after germinal matrix hemorrhage, and the neurotrophic phenotype maybe neuroprotective. However, the phenotype transformation and the way by which neuron-microglia dialogue remain unclear. We raise the hypothesis that a cannabinoid receptor2 agonist (JWH133) accelerates the CX3CR1+ microglia secreting neurotrophic factors and restores damaged neuronal circuit. Here, we report a novel function of JWH133 in transforming the microglia CX3CR1 positive that secrete brain-derived neurotrophic factor (BDNF), which triggers neuron proliferation and neuronal restoration. Using a collagen VII-induced GMH model in rat pups postnatal day 7 (P7), we found that the drug showed robust activity in neuronal precursors. Moreover, the FA value of DTI in the internal zone revealed the positive effects of JWH133 on neural restoration. CX3CR1, a critical modulating molecule expressed in microglia, was upregulated after treatment with JWH133 and the corresponding shRNA (NM_133534.1) was used to silence the expression of CX3CR1. 3 days after treatment with JWH133, we detected reduced expression of biomarkers for neural progenitor cells (NPCs) in pups pre-injected in the lateral ventricular tissue with CX3CR1 shRNA, but not in pups injected with control shRNA. Overall, this study provides evidence that JWH133 promoted a neurotrophic phenotype of microglia (CX3CR1+ microglia), beyond merely alleviating microglial proliferation and inflammation. Moreover, JWH133 restored impaired neuronal circuit, which represent a novel therapeutic strategy following GMH in clinic.