Na+/K+-ATPase is a novel target to treat anxiety / 中国药理学与毒理学杂志

OBJECTIVE Na+/K+-ATPase(NKA)is a large membrane protein expressed universally in all cells.It is indispensable for the maintenance of ionic gradient.We previously reported that the dysfunction of this pump in neurons and astrocytes contributes to stroke and neurodegenerative diseases,respectively.However,its roles in the microglia and stress-related diseases are still unclear.METHODS Two classical models,chronic restraint stress(CRS)model and electronic foot shock(ES)model,were used to study the pathogenesis of anxi-ety in either NKAα1 global knockout(NKAα1 GKO)mice or NKA α1 conditional knockout(NKAα1 CKO)mice.Behavioral tests like open-field test,elevated plus maze,Morris water maze,novel object recognition test and gait imaging test were performed.A variety of molecular bio-logical methods were employed,including RNA sequenc-ing(RNA-seq)analyses,immunofluorescence and elec-trophysiological recordings etc.RESULTS NKAα1 defi-ciency had a broad impact on physical stress-induced anxiety-like behavior,but failed to exacerbate CRS induced memory deficits.Electrophysiology experiment showed that NKAα1 GKO and NKAα1 CKO mice exhibit-ed neuronal hyperexcitability under chronic stress.The underlying mechanisms may involve neuroinflammation,as NKAα1 deficiency exacerbated stress-induced microg-lia activation in vivo.Similarly,inhibition or downregula-tion of NKA α 1 aggravated LPS + ATP-induced inflam-mation in vitro.DR5-12D,a monoclonal antibody against the DR-region of NKAa1,improved stress-induced anxiety-like behavior through amelioration of the neuronal hyper-excitability and neurogenesis deficit in the ventral hippo-campus of mice.CONCLUSION NKA is closely related to neuroinflammation in microglia and DR-region of NKA a1 subunit may serve as a novel target to treat stress-induced anxiety.

Mechanism of Mongolian drug Naru-3 in initiation of neuroinflammation of neuropathic pain from MMP9/IL-1β signaling pathway / 中国中药杂志

Neuropathic pain(NP) has similar phenotypes but different sequential neuroinflammatory mechanisms in the pathological process. It is of great significance to inhibit the initiation of neuroinflammation, which has become a new direction of NP treatment and drug development in recent years. Mongolian drug Naru-3 is clinically effective in the treatment of trigeminal neuralgia, sciatica, and other NPs in a short time, but its pharmacodynamic characteristics and mechanism of analgesia are still unclear. In this study, a spinal nerve ligation(SNL) model simulating clinical peripheral nerve injury was established and the efficacy and mechanism of Naru-3 in the treatment of NPs was discussed by means of behavioral detection, side effect evaluation, network analysis, and experimental verification. Pharmacodynamic results showed that Naru-3 increased the basic pain sensitivity threshold(mechanical hyperalgesia and thermal radiation hyperalgesia) in the initiation of SNL in animals and relieved spontaneous pain, however, there was no significant effect on the basic pain sensitivity threshold and motor coordination function of normal animals under physiological and pathological conditions. Meanwhile, the results of primary screening of target tissues showed that Naru-3 inhibited the second phase of injury-induced nociceptive response of formalin test in mice and reduced the expression of inflammatory factors in the spinal cord. Network analysis discovered that Naru-3 had synergy in the treatment of NP, and its mechanism was associated with core targets such as matrix metalloproteinase-9(MMP9) and interleukin-1β(IL-1β). The experiment further took the dorsal root ganglion(DRG) and the stage of patho-logical spinal cord as the research objects, focusing on the core targets of inducing microglial neuroinflammation. By means of Western blot, immunofluorescence, agonists, antagonists, behavior, etc., the mechanism of Naru-3 in exerting NP analgesia may be related to the negative regulation of the MMP9/IL-1β signaling pathway-mediated microglia p38/IL-1β inflammatory loop in the activation phase. The relevant research enriches the biological connotation of Naru-3 in the treatment of NP and provides references for clinical rational drug use.

Recent Progress in the Development of TSPO PET Ligands for Neuroinflammation Imaging in Neurological Diseases / 대한핵의학회잡지

Neuroinflammation is heavily associated with various neurological diseases including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and stroke. It is strongly characterized by the activation of microglia which can be visualized using position emission tomography (PET). Traditionally, translocator protein 18 kDa (TSPO) has been the preferred target for imaging the inflammatory progression of the microglial component. TSPO is expressed in the outer mitochondrial membrane and present in very low concentrations in the healthy human brain, but is markedly upregulated in response to brain injury and inflammation. Due to its value as a marker of microglial activation and subsequent utility for evaluating neuroinflammation in CNS disorders, several classes of TSPO radioligands have been developed and evaluated. However, the application of these second-generation TSPO radiotracers has been subject to several limiting factors, including a polymorphism that affects TSPO binding. This review focuses on recent developments in TSPO imaging, as well as current limitations and suggestions for future directions from a medical imaging perspective.

Mechanism of Anti-α-Synuclein Immunotherapy

Immunization therapy targeting α-synuclein has emerged as a promising approach for Parkinson's disease and perhaps for other synucleinopathies. Several antibodies have shown therapeutic effects in mouse models of synucleinopathies and have alleviated the pathological and behavioral phenotypes of these mice. The mechanisms through which the immunization therapy works were initially puzzling, especially given that α-synuclein is a typical cytosolic protein. Recent studies, however, suggested that extracellular α-synuclein is an important pathogenic entity, and hence, a target for immunotherapy. Here, we review the literature describing immunization therapy for synucleinopathies in mouse models and provide current thoughts on the potential mechanisms underlying the therapeutic effects of α-synuclein immunotherapy.

Shenqi Fuzheng Injection (SFI) inhibits irradiation-induced brain injury / 中华放射医学与防护杂志

Objective To explore the effect of SFI in radiation-induced mice brain injury after 20 Gy cranial radiation.Methods The mice were divided into three groups:(1) control group,(2) RT-only group:the whole brain was irradiated with a dose of 20 Gy,(3) RT and SFI group:SFI at 20 ml/kg/d from 4 weeks after 20 Gy cranial radiation theraty(CRT).Results Morris water maze test showed that the latency of the irradiated group was longer than control group and SFI improved the cognitive function of mice (t =6.34,6.70,P ＜0.05).The expression of TNF-α reached to the highest level at 3 h after irradiation,and then it decreased but got the second higher level again at 4 weeks after irradiation.The expression of IL-1 β reached to the highest level at 72 h after irradiation and decreased until 4 weeks after irradiation.SFI decreased both expressions of TNF-α (t =11.34,9.70,6.07,P ＜ 0.05) and IL-1 β (t =12.27,5.70,7.52,P ＜ 0.05).Immune florescence staining showed that SFI reduced the number of activated microglia (t =12.35,8.64,7.82,P ＜ 0.05)and inhibited the translocation of p65 of microglia after irradiation.Conclusions Findings suggest that SFI may decrease microglial activation and suppress the expression of TNF-α and IL-1β by inhibiting the translocation of NF-κB p65 and then attenuate irradiation-induced brain injury.

Differential activation of M1 and M2 microglial in spinal cord dorsal horn of rats at the early stage after sciatic nerve injury / 中国比较医学杂志

Objective To study the type variation of microglial activation in spinal dorsal horn of rats after sciatic nerve injury.Methods Healthy adult male Sprague-Dawley rats were randomly divided into the control and experimental groups, 24 rats in each group.The experimental group underwent ligation of sciatic nerve trunk to generate nerve injury in the rats.The pain behavior in the rats was measured at the 1th, 7th and 14th postoperative days, and the changes of microglial activation in the rat lumbar spinal cord dorsal horn was detected by immunofluorescence staining.qRT-PCR assay was used to validate the activation trends of M1 and M2 types of microglia cells.Results No significant changes were found in the microglial cells in the spinal cord dorsal horn of rats in the sham-operation group during 14 days after operation.In the sciatic nerve ligation group at 1 day after operation, no significant change was observed in the number of microglial cells, but the expression of marker of M1 microglia was significantly increased.At 7 and 14 days after operation, the number of microglial cells and the expression of M1 microglia marker in the spinal cord dorsal horn were increased significantly.Conclusions Microglia activation in the spinal dorsal horn starts at the first day after sciatic nerve injury, and lasts at least for two weeks after the operation.M1 microglia activation dominates during this period.

Regulatory Effect of 25-hydroxyvitamin D3 on Nitric Oxide Production in Activated Microglia

Microglia are activated by inflammatory and pathophysiological stimuli in neurodegenerative diseases, and activated microglia induce neuronal damage by releasing cytotoxic factors like nitric oxide (NO). Activated microglia synthesize a significant amount of vitamin D3 in the rat brain, and vitamin D3 has an inhibitory effect on activated microglia. To investigate the possible role of vitamin D3 as a negative regulator of activated microglia, we examined the effect of 25-hydroxyvitamin D3 on NO production of lipopolysaccharide (LPS)-stimulated microglia. Treatment with LPS increased the production of NO in primary cultured and BV2 microglial cells. Treatment with 25-hydroxyvitamin D3 inhibited the generation of NO in LPS-activated primary microglia and BV2 cells. In addition to NO production, expression of 1-alpha-hydroxylase and the vitamin D receptor (VDR) was also upregulated in LPS-stimulated primary and BV2 microglia. When BV2 cells were transfected with 1-alpha-hydroxylase siRNA or VDR siRNA, the inhibitory effect of 25-hydroxyvitamin D3 on activated BV2 cells was suppressed. 25-Hydroxyvitamin D3 also inhibited the increased phosphorylation of p38 seen in LPS-activated BV2 cells, and this inhibition was blocked by VDR siRNA. The present study shows that 25-hydroxyvitamin D3 inhibits NO production in LPS-activated microglia through the mediation of LPS-induced 1-alpha-hydroxylase. This study also shows that the inhibitory effect of 25-hydroxyvitamin D3 on NO production might be exerted by inhibiting LPS-induced phosphorylation of p38 through the mediation of VDR signaling. These results suggest that vitamin D3 might have an important role in the negative regulation of microglial activation.

The effect of bone marrow mononuclear cells transplantation on brain injury after intracerebral hemorrhage in rats / 中华行为医学与脑科学杂志

Objective To investigate the effect of intravenously transplanted bone marrow mononuclear cells (BMMNCs) on brain injury and inflammation after intracerebral hemorrhage(ICH) in rats.Methods Experimnental ICH models were performed by stereotaxic injection collagenase Ⅳ into caudate putamen,rats that underwent ICH were randomly divided into four groups:sham operation group,ICH group,PBS group,BMMNC-treated group.The BMMNCs were injected intravenously into rats after ICH.The neurobehavioral function was evaluated on days 1,3,7,14 by the modified neurological severity score,and the brain edema was examined by wet-dry weighting method on day 3 after cell transplantation.Immumofluorecence staining was used to identify the number of activation of microglia and infiltration of neutrophils in the brain after ICH.Results The neurological score in BMMNCtreated group on days 7,14 was significantly improved compared with those in ICH group and PBS group(P＜O.05).Compared to the ICH group ((81.09 ± 0.83) ％) and PBS group ((80.99 ± 0.79) ％),there was a significant decreasc in thc brain water content in BMMNC-treated group((78.62±0.97) ％) (P＜0.05).The number of activation of microglia and infiltration of neutrophils were both significantly lower in BMMNC-treated group ((55.8±22.1)/mm2,(49.6± 12.9)/mm2) compared to ICH group and PBS group (respectively (125.0 ± 20.7) /mm2,(86.8±13.6/mm2))(P＜0.01).Conclusion Administration of BMMNCs can significantly reduce edema and improve neurologic function by inhibiting the activation of microglia and infiltration of neutrophils.