QBT improved cognitive dysfunction in rats with vascular dementia by regulating the Nrf2/xCT/GPX4 and NLRP3/Caspase-1/GSDMD pathways to inhibit ferroptosis and pyroptosis of neurons.

BACKGROUND: The novel phthalein component QBT, extracted from Ligusticum chuanxiong, shows promising biological activity against cerebrovascular diseases. This study focused on ferroptosis and pyroptosis to explore the effects of QBT on nerve injury, cognitive dysfunction, and related mechanisms in a rat model of vascular dementia (VaD). METHODS: We established a rat model of VaD and administered QBT as a treatment. Cognitive dysfunction in VaD rats was evaluated using novel object recognition and Morris water maze tests. Neuronal damage and loss in the brain tissues of VaD rats were assessed with Nissl staining and immunofluorescence. Furthermore, we investigated the neuroprotective mechanisms of QBT by modulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/cystine-glutamate antiporter (xCT)/glutathione peroxidase 4 (GPX4) and Nod-like receptor family pyrin domain-containing 3 (NLRP3)/cysteine-requiring aspartate protease-1 (Caspase-1)/Gasdermin D (GSDMD) pathways to inhibit ferroptosis and pyroptosis both in vivo and in vitro. RESULTS: Our findings indicated that QBT significantly ameliorated neuronal damage and cognitive dysfunction in VaD rats. Additionally, QBT reversed abnormal changes associated with ferroptosis and pyroptosis in the brains of VaD rats, concurrently up-regulating the Nrf2/xCT/GPX4 pathway and down-regulating the NLRP3/Caspase-1/GSDMD pathway to inhibit ferroptosis and pyroptosis in neuronal cells, thereby exerting a neuroprotective role. CONCLUSION: In summary, QBT effectively mitigated neuronal damage and cognitive dysfunction in VaD rats, demonstrating a neuroprotective effect by inhibiting ferroptosis and pyroptosis in neuronal cells. This study offers a novel perspective and theoretical foundation for the future development of drugs targeting VaD.

A novel phthalein component ameliorates neuroinflammation and cognitive dysfunction by suppressing the CXCL12/CXCR4 axis in rats with vascular dementia.

ETHNOPHARMACOLOGICAL RELEVANCE: Chuanxiong, a plant of the Umbelliferae family, is a genuine medicinal herb from Sichuan Province. Phthalides are one of its main active components and exhibit good protective effect against cerebrovascular diseases. However, the mechanism by which phthalides exert neuroprotective effects is still largely unclear. AIM OF THE STUDY: In this study, we extracted a phthalein component (named as QBT) from Ligusticum Chuanxiong, and investigated its neuroprotective effects against vascular dementia (VaD) rats and the underlying mechanism, focusing on the chemokine 12 (CXCL12)/chemokine (C-X-C motif) receptor 4 (CXCR4) axis. METHODS: A rat model of VaD was established, and treated with QBT. Cognitive dysfunction in VaD rats was assessed using the Y-maze, new object recognition, and Morris water maze tests. Neuronal damage and inflammatory response in VaD rats were examined through Nissl staining, immunofluorescence, enzyme-linked immunospecific assay, and western blotting analysis. Furthermore, the effects of QBT on CXCL12/CXCR4 axis and its downstream signaling pathways, Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/nuclear factor-κB (NF-κB), were investigated in VaD rats and BV2 microglial cells exposed to oxygen glucose deprivation. RESULTS: QBT significantly alleviated cognitive dysfunction and neuronal damage in VaD rats, along with inhibition of VaD-induced over-activation of microglia and astrocytes and inflammatory response. Moreover, QBT exhibited anti-inflammatory effects by inhibiting the CXCL12/CXCR4 axis and its downstream JAK2/STAT3 and PI3K/AKT/NF-κB pathways, thereby attenuating the neuroinflammatory response both in vivo and in vitro. CONCLUSION: QBT effectively mitigated neuronal damage and cognitive dysfunction in VaD rats, exerting neuroprotective effects by suppressing neuroinflammatory response through inhibition of the CXCL12/CXCR4 axis.

Modulation of Xiongdanjiuxin pills on the gut-liver axis in high-fat diet rats.

AIM: Xiongdanjiuxin pill (XP) is a traditional Chinese medicine formula for the prevention and treatment of hyperlipidemia (HLP) and related complications. In this study, the gut-liver axis was used as the breakthrough point to analyze the therapeutic effect and potential mechanism of XP on HLP model rats and related complications. MAIN METHODS: We used high-fat diet (HFD) to establish the HLP model of rats and treated them with XP. The 16S rRNA sequencing method was used to explore the effect of XP on the gut microbiota of HFD rats, and the effects of XP on ileum pathology, intestinal barrier and circulatory inflammation in HFD rats were also investigated. We further explored the molecular mechanism of XP treating liver inflammation in rats with HFD by regulating toll-like receptor 4 (TLR4) signaling. KEY FINDINGS: We found that XP could regulate the imbalance of gut microbiota in HFD rats, and up-regulate the expression of tight junction protein in intestinal epithelium of HFD rats, thereby improving the intestinal barrier damage and intestinal inflammatory response. In addition, XP could significantly reduce the levels of inflammatory cytokines in HFD rats, and inhibit TLR4 signaling pathway, thereby reducing liver inflammation in HFD rats. SIGNIFICANCE: XP can effectively improve the imbalance of gut-liver axis in hyperlipidemic rats and alleviate the inflammatory damage of liver. Its mechanism may be related to regulating the disorder of gut microbiota and inhibiting TLR4 signal pathway, so as to achieve the therapeutic effect on hyperlipidemic fatty liver in rats.

Probiotics Improve Cognitive Impairment by Decreasing Bacteria-Related Pattern Recognition Receptor-Mediated Inflammation in the Gut-Brain Axis of Mice.

INTRODUCTION: Some studies have found that probiotics can improve cognitive impairment in Alzheimer's disease, although the specific molecular mechanism by which this occurs has not been reported. Our previous research found that probiotics inhibited bacteria-related Toll-like receptor 4- and retinoic-acid-inducible gene-I-mediated nuclear factor-κB signaling pathways to improve cognitive impairment. However, it is unclear whether probiotics have similar effects on other pattern recognition receptors that respond to bacteria. METHODS: Nine-month-old senescence-accelerated mouse prone 8 (SAMP8) mice received ProBiotic-4 (a mixture of Lactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus casei, and Bifidobacterium lactis) orally for 12 weeks. The effects on other bacteria-related pattern recognition receptors were then investigated. RESULTS: ProBiotic-4-treated SAMP8 mice showed improvement in memory deficits, synaptic and cerebral neuronal injuries, and microglial activation. ProBiotic-4 also markedly increased the expression of intestinal tight junction proteins (i.e., claudin-1, occludin, and zonula occluden-1), decreased the expression of interleukin-1ß at both the mRNA and protein levels, and reduced the expression of caspase-11, cleaved caspase-1, and α-kinase 1 (ALPK1) in the intestine and brain. CONCLUSIONS: These findings suggest that probiotics may have therapeutic potential for the treatment of inflammation in the gut-brain axis and for cognitive impairment. The mechanism of action of probiotics appears to be related to inhibition of the caspase-11/caspase-1 pathway and reduction of ALPK1 expression.

Phthalide derivative CD21 regulates the platelet- neutrophil extracellular trap-thrombin axis and protects against ischemic brain injury in rodents.

Prothrombotic and proinflammatory properties of neutrophil extracellular traps (NETs) contribute to brain damage after ischemic stroke. CD21 is a novel phthalide neuroprotectant against cerebral ischemia in rodents. This study investigated effects of CD21 on the platelet-NET-thrombin axis and ischemic brain injury and the underlying mechanism. CD21 exerteddose-dependent neuroprotectionin rats that were subjected to2 h middle cerebral artery occlusion,dose-dependentlyinhibited adenosine diphosphate-mediatedplatelet aggregationin rats, and dose-dependentlyexertedanti-thrombotic activityin rodents that received a collagen-epinephrine combination, ferric chloride, or an arteriovenous shunt. Equimolar CD21 doses exerted stronger efficacy than 3-N-butylphthalide (NBP, natural phthalide for the treatment of ischemic stroke). CD21 dose-dependently improved regional cerebral blood flow, neurobehavioral deficits, and infarct volume in mice that were subjected to photothrombotic stroke (PTS). CD21 (13.79 mg/kg, i.v.) significantly decreased NET components (plasma dsDNA concentrations; mRNA levels of elastase, myeloperoxidase, and neutrophil gelatinase-associated lipocalin and protein level of citrullinated histone H3 in ischemic brain tissues), mRNA and protein levels of peptidyl-arginine deiminase 4 (PDA4, NET formation enzyme), and mRNA levels of NET-related inflammatory mediators (interleukin-1ß, interleukin-17A, matrix metalloproteinase 8, and matrix metalloproteinase 9) in ischemic brain tissues, despite no effect on mRNA levels of deoxyribonuclease I (NET elimination enzyme). Pretreatment with compound C (inhibitor of adenosine monophosphate-activated protein kinase [AMPK]) significantly reversed the inhibitory effects of CD21 on NETs, PDA4, and inflammatory mediators in PTS mice. These results suggest that CD21 might regulate the platelet-NET-thrombin axis and protect against ischemic brain injury partly through the induction of AMPK activation.

Neuroprotective effect of alpha-kinase 1 knockdown against cerebral ischemia through inhibition of the NF-κB pathway and neuroinflammation.

BACKGROUND: Activation of the nuclear factor B (NF-κB) signaling pathway by pattern recognition receptors (PRRs) is regarded as a crucial mechanism of neuroinflammation and brain injury after acute ischemic stroke. The stimulation of alpha-kinase 1 (ALPK1), a newly identified PRR, triggers NF-κB activation and an inflammatory response. Longitudinal population-based genetic epidemiological studies suggest that the ALPK1 gene is a susceptible site to ischemic stroke. However, the function of ALPK1 in the central nervous system remains unclear. The present study explored the role of ALPK1 in acute ischemic stroke. METHODS: BV2 microglial cells were stimulated with conditioned medium (CM) that was collected from oxygen and glucose deprivation (OGD)-treated HT22 neurons, and a murine brain ischemia model was established to detect the changes of ALPK1 expression. We used lentivirus to knockdown ALPK1 to explore the effects of ALPK1 in cerebral ischemia models in vitro and in vivo. RESULTS: We observed a significant increase of ALPK1 expression in BV2 cells that were stimulated with OGD CM. The knockdown of ALPK1 inhibited the phosphorylation of tumor necrosis factor receptor associated factor-interacting protein with a forkhead-associated domain (TIFA), the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), the activation of NF-κB, and the levels of proinflammatory factors in the BV2 cells. We also verified a neuroprotective effect of ALPK1 knockdown against ischemic brain injury through inhibition of the TIFA/TRAF6/NF-κB pathway and neuroinflammation in mice. CONCLUSIONS: This study demonstrates that ALPK1 is implicated in sterile inflammatory injury after acute brain ischemia, which provides first evidence for the therapeutic potential of ALPK1 inhibition in ischemic stroke.

Phthalide derivative CD21 attenuates tissue plasminogen activator-induced hemorrhagic transformation in ischemic stroke by enhancing macrophage scavenger receptor 1-mediated DAMP (peroxiredoxin 1) clearance.

BACKGROUND: Hemorrhagic transformation (HT) is a critical issue in thrombolytic therapy in acute ischemic stroke. Damage-associated molecular pattern (DAMP)-stimulated sterile neuroinflammation plays a crucial role in the development of thrombolysis-associated HT. Our previous study showed that the phthalide derivative CD21 attenuated neuroinflammation and brain injury in rodent models of ischemic stroke. The present study explored the effects and underlying mechanism of action of CD21 on tissue plasminogen activator (tPA)-induced HT in a mouse model of transient middle cerebral artery occlusion (tMCAO) and cultured primary microglial cells. METHODS: The tMCAO model was induced by 2 h occlusion of the left middle cerebral artery with polylysine-coated sutures in wildtype (WT) mice and macrophage scavenger receptor 1 knockout (MSR1-/-) mice. At the onset of reperfusion, tPA (10 mg/kg) was intravenously administered within 30 min, followed by an intravenous injection of CD21 (13.79 mg/kg/day). Neuropathological changes were detected in mice 3 days after surgery. The effect of CD21 on phagocytosis of the DAMP peroxiredoxin 1 (Prx1) in lysosomes was observed in cultured primary microglial cells from brain tissues of WT and MSR1-/- mice. RESULTS: Seventy-two hours after brain ischemia, CD21 significantly attenuated neurobehavioral dysfunction and infarct volume. The tPA-infused group exhibited more severe brain dysfunction and hemorrhage. Compared with tPA alone, combined treatment with tPA and CD21 significantly attenuated ischemic brain injury and hemorrhage. Combined treatment significantly decreased Evans blue extravasation, matrix metalloproteinase 9 expression and activity, extracellular Prx1 content, proinflammatory cytokine mRNA levels, glial cells, and Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) pathway activation and increased the expression of tight junction proteins (zonula occludens-1 and claudin-5), V-maf musculoaponeurotic fibrosarcoma oncogene homolog B, and MSR1. MSR1 knockout significantly abolished the protective effect of CD21 against tPA-induced HT in tMCAO mice. Moreover, the CD21-induced phagocytosis of Prx1 was MSR1-dependent in cultured primary microglial cells from WT and MSR1-/- mice, respectively. CONCLUSION: The phthalide derivative CD21 attenuated tPA-induced HT in acute ischemic stroke by promoting MSR1-induced DAMP (Prx1) clearance and inhibition of the TLR4/NF-κB pathway and neuroinflammation.

Nrf2 signalling pathway and autophagy impact on the preventive effect of green tea extract against alcohol-induced liver injury.

OBJECTIVES: To explore the potential molecular mechanism underlying the effect of green tea extract (TE), rich in tea polyphenols (TPs), on improving alcohol-induced liver injury. METHODS: Mice were intragastrically treated with 50% (v/v) alcohol administration (15 ml/kg BW) with or without three doses of TE (50, 120 and 300 mg TPs/kg BW) daily for 4 weeks, and biological changes were tested. KEY FINDINGS: The TE improved the functional and histological situations in the liver of the mice accepted alcohol administration, including enzymes for alcohol metabolism, oxidative stress and lipid accumulation. Interestingly, the TE increased the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2), with the decreasing expression of kelch-like ECH-associated protein 1 (Keap1), indicating the association between the effect of TE with Nrf2-mediated antioxidant signalling. Moreover, the TE restored the activity of autophagy, showing as lifted Beclin-1 expression, LC3B-II/LC3B-I ratio, and decreased p62 expression. Importantly, all these effects were dose-dependent. CONCLUSIONS: These findings provide a new notion for the first time that the TE preventing against alcohol-induced liver injury is closely related to accelerated metabolism of alcohol and relieved oxidative stress, which is associated with Nrf2 signalling activation and autophagy restoration, thus the reduction of lipid accumulation in liver.

Gut Microbiota in Tumor Microenvironment: A Critical Regulator in Cancer Initiation and Development as Potential Targets for Chinese Medicine.

Cancer is a disease with a high mortality and disability rate. Cancer consists not only of cancer cells, but also of the surrounding microenvironment and tumor microenvironment (TME) constantly interacting with tumor cells to support tumor development and progression. Over the last decade, accumulating evidence has implicated that microbiota profoundly influences cancer initiation and progression. Most research focuses on gut microbiota, for the gut harbors the largest collection of microorganisms. Gut microbiota includes bacteria, viruses, protozoa, archaea, and fungi in the gastrointestinal tract, affecting DNA damage, host immune response and chronic inflammation in various types of cancer (i.e., colon cancer, gastric cancer and breast cancer). Notably, gut dysbiosis can reshape tumor microenvironment and make it favorable for tumor growth. Recently, accumulating studies have attached the importance of traditional Chinese medicine (TCM) to cancer treatments, and the bioactive natural compounds have been considered as potential drug candidates to suppress cancer initiation and development. Interestingly, more recent studies demonstrate that TCM could potentially prevent and suppress early-stage cancer progression through the regulation of gut microbiota. This review is on the purpose of exhausting the significance of gut microbiota in the tumor microenvironment as potential targets of Chinese medicine.

Age-related cognitive decline is associated with microbiota-gut-brain axis disorders and neuroinflammation in mice.

Age-related cognitive decline is associated with chronic low grade neuroinflammation that may result from a complex interplay among many factors, such as bidirectional communication between the central nervous system (CNS) and gut microbiota. The present study used 2-month-old (young group) and 15-month-old (aged group) male C57BL/6 mice to explore the potential association between age-related cognitive decline and the microbiota-gut-brain axis disorder. We observed that aged mice exhibited significant deficits in learning and memory, neuronal and synaptic function compared with young mice. Aged mice also exhibited significant dysbiosis of the gut microbiota. Disruptions of the intestinal barrier and blood-brain barrier were also observed, including increases in intestinal, low-grade systemic and cerebral inflammation. Furthermore, plasma and brain levels of lipopolysaccharide (LPS) were significantly higher in aged mice compared with young mice, with increasing expression of Toll-like receptor 4 (TLR4) and myeloid differential protein-88 (MyD88) and the nuclear translocation of nuclear factor κB (NF-κB) in intestinal and brain tissues. These findings showed that microbiota-gut-brain axis dysfunction that occurs through LPS-induced activation of the TLR4/NF-κB signaling pathway is implicated in age-related neuroinflammation and cognitive decline.

Neuroprotective Effect of Phthalide Derivative CD21 against Ischemic Brain Injury:Involvement of MSR1 Mediated DAMP peroxiredoxin1 Clearance and TLR4 Signaling Inhibition.

The macrophage scavenger receptor 1 (MSR1)-induced resolution of neuroinflammation may be a novel therapeutic strategy for ischemic stroke. Our previous study showed that the neuroprotective and anti-inflammatory effects of phthalide are associated with the inhibition of the post-ischemic damage-associated molecular pattern (DAMP)/Toll-like receptor 4 (TLR4) pathway. This study investigated the effects of the phthalide derivative CD21 on ischemic brain injury and the mechanism underlying MSR1-induced resolution of neuroinflammation. Using a rat model of 2 h transient middle cerebral artery occlusion (MCAO), MSR1-induced peroxiredoxin1 (PRX1) clearance in RAW264.7 macrophages were investigated. We show here that CD21 significantly ameliorated infarct volumes and neurological deficits in a dose-dependent manner with a ≥ 12 h therapeutic time window. Moreover, administration of 5 mg/kg/day CD21 over 24 h significantly reduced pathological damages, with associated inhibition of PRX1 expression, reduced TLR4/nuclear factor-κB activation and the suppression of the inflammatory response in MCAO rats. Furthermore, the expression of MAFB/MSR1 in the ischemic brain was elevated and the phagocytosis of PRX1 in CD68-positive macrophages isolated from the ischemic brain was enhanced. Further in vitro studies show that CD21 (20 µM) strongly enhanced the Msr1 mRNA and MSR1 protein levers in RAW264.7 cells and PRX1 internalization in cellular lysosomes, which were significantly reversed by N-acetylcysteine treatment. These results suggest that CD21 may exert neuroprotective and anti-inflammatory effects with a wide time window for the treatment of ischemic stroke. The anti-stroke effects of CD21 appear to be mediated partially via the induction of MSR1-promoted DAMP (PRX1) clearance, TLR4/nuclear factor-κB pathway inhibition, and the resolution of inflammation. Graphical Abstract The neuroprotective action of CD21 was associated with the resolution of neuroinflammation through enhancement of the MAFB-MSR1 pathway that leads to DAMP (PRX1) phagocytosis and TLR4 pathway inhibition. Red solid arrows represent promotion, red dotted arrow represents the positive correlation, green arrows represent inhibition.

Klotho overexpression improves amyloid-ß clearance and cognition in the APP/PS1 mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is the most prevalent type of dementia, characterized by the presence of amyloid-ß (Aß) plaques. We previously reported that Klotho lowered Aß levels in the brain and protected against cognitive deficits in amyloid precursor protein/presenilin 1(APP/PS1) mice. However, the underlying mechanism remains unclear. In this study, we induced intracerebral Klotho overexpression in 13-month-old APP/PS1 mice by injecting lentivirus that carried full-length mouse Klotho cDNA in the lateral ventricle of the brain. We examined the effects of Klotho overexpression on cognition, Aß burden, Aß-related neuropathology, microglia transformation, and Aß transport systems in vivo. Additionally, we investigated the effects of Klotho on Aß transport at the blood-cerebrospinal fluid barrier by knocking down Klotho in primary human choroid plexus epithelial cells (HCPEpiCs). The upregulation of Klotho levels in the brain and serum significantly ameliorated Aß burden, neuronal and synaptic loss and cognitive deficits in aged APP/PS1 mice. Klotho treatment significantly inhibited NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) and the subsequent transformation of microglia to the M2 type that may enhance microglia-mediated Aß clearance. Meanwhile, Klotho overexpression also regulated Aß transporter expression, which may promote Aß transporter-mediated Aß clearance. Moreover, the ability of HCPEpiCs to transport Aß in vitro was also significantly impaired by Klotho knockdown. Given the neuroprotective effect of Klotho overexpression, the present findings suggest that Klotho should be further investigated as a potential therapeutic target for AD.

Phthalide derivative CD21 alleviates cerebral ischemia-induced neuroinflammation: Involvement of microglial M2 polarization via AMPK activation.

Microglia can be activated to become the classic phenotype (M1) or alternative phenotype (M2), which play an important role in regulating neuroinflammatory response and tissue repair after ischemic stroke. CD21, a novel phthalide derivative, is a potential neuroprotectant against ischemic brain injury. The present study further investigated the effects of CD21 on post-ischemic microglial polarization and the underlying mechanisms. Transient middle cerebral artery occlusion (tMCAO) was used as a mouse model of ischemic stroke, while BV2 cells stimulated with conditioned medium collected from oxygen-glucose deprivation-treated HT22 cells were used in in vitro ischemic studies. The current results showed that CD21 dose-dependently and significantly improved neurological outcomes in tMCAO mice. Biochemical analyses revealed that CD21 decreased the expression of M1 phenotype markers (CD86, interleukin-1ß and inducible nitric oxide synthase) and increased the expression of M2 phenotype markers (CD206, interleukin-10 and YM1/2) in both ischemic brain tissues and BV2 cells. Meanwhile, CD21 decreased the production of proinflammatory cytokines (interleukin-1ß, interleukin-6 and tumor necrosis factor-α), promoted the release of the antiinflammatory cytokine (interleukin-10), and enhanced the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK) in ischemic brain tissue and BV2 cells. Furthermore, the AMPK inhibitor (compound C) reversed these effects of CD21 in BV2 cells. These findings indicate that CD21 alleviates post-ischemic neuroinflammation through induction of microglial M2 polarization that is at least in part medicated by AMPK activation, suggesting that CD21 may be a promising candidate for protecting against ischemic brain injury.

Phthalide derivative CD21 ameliorates ischemic brain injury in a mouse model of global cerebral ischemia: involvement of inhibition of NLRP3.

The activation of NLRP3 inflammasome is closely related to ischemic brain injury and inhibition of NLRP3 inflammasome activation may be a new therapeutic strategy for ischemic stroke. Our previous studies showed that ligustilide (LIG) had a dose-dependent neuroprotective effect on various models of cerebral ischemia and dementia in vivo and in vitro. CD21, a kind of phthalide derivative, was modified from LIG. In this study, we established a global cerebral ischemia-reperfusion model in mice by bilateral common carotid artery ligation (2VO), and explored the neuroprotective effect of CD21 and its anti-inflammatory mechanism on cerebral ischemia mice. CD21 significantly improved weight loss, neurobehavioral deficits and neurons loss in hippocampal CA1 and caudate putamen (CPu) subregions, which were induced by 2VO in mice. CD21 significantly inhibited the overactivation of astrocyte and microglia, and decreased the mRNA level of IL-6, TNF-α and IL-1ß. Moreover, CD21 significantly inhibited the activation of TLR4/NF-κB signaling pathway mediated by HMGB1 and NLRP3/ASC/Caspase-1 signaling pathway mediated by Cathepsin B, thus inhibiting the activation of NLRP3 inflammasome. Our results demonstrated that CD21 may exert a neuroprotection by inhibiting NLRP3 inflammasome activation after cerebral ischemia. These findings provide a new strategy for the treatment of ischemic stroke.

[Effects of Low Concentration Hydrogen Inhalation on Asthma and Sleep Function in Mice].

OBJECTIVE: This study was designed to investigate the effects of low concentration hydrogen inhalation on asthma and sleep function in mice and the potential mechanism. METHODS: In the asthma experiment, BALB/c mice were randomly divided into normal control group, asthma model group and hydrogen treatment group. After establishing ovalbumin (OVA)-induced asthma model, the hydrogen treatment group mice were treated by inhalation of hydrogen (24-26 mL/L per day) for 7 consecutive days, and the normal control group and asthma model group mice received similar treatment by inhalation of air. The levels of interleukin (IL)-4, IL-13, and interferon-γ (IFN-γ) in bronchoalveolar lavage fluid (BALF) were measured by commercially available ELISA kits. The levels of malondialdehyde (MDA) and glutathione (GSH), as well as the activity of superoxide dismutase (SOD) in lung tissue were detected by colorimetric assays. The pathological changes in lung tissue were assessed by HE staining. In the sleep experiment, ICR mice were randomly divided into blank control group and 1 d, 3 d, 5 d hydrogen treatment groups and diazepam group. The effects of inhalation of 24-26 mL/L per day hydrogen on the sleep duration induced by intraperitoneal injection of upper-threshold dose of sodium pentobarbital and the sleep latency in response to subthreshold dose were evaluated. RESULTS: In the asthma experiment, the asthma model group showed higher levels of IL-4 and IL-13 ( P<0.05) and lower levels of IFN-γ ( P<0.001) in BALF, as compared to the normal control group. The content of MDA in lung tissue was also significantly increased ( P<0.01), companied by a decreased GSH concentration ( P <0.05) and a mildly reduced SOD activity ( P>0.05). Compared to the asthma model group, treatment with hydrogen significantly decreased the levels of IL-4 and IL-13 and increased the level of IFN-γ in BALF ( P<0.05). Moreover, without alteration of the MDA production ( P>0.05), hydrogen inhalation greatly increased GSH level and restored the SOD activity ( P<0.05) in lung tissue. Additionally, the HE staining data showed that the hydrogen treatment attenuated the pulmonary histopathological changes. In the sleep experiment, compared with the blank control group, the sleep latency was significantly shorter ( P<0.05) and the sleep duration was longer ( P<0.001) in all the hydrogen treatment groups after receiving an upper-threshold dose of sodium pentobarbital. Meanwhile, in all the hydrogen treatment groups, the sleep latency was significantly longer ( P<0.001) and the sleep duration was shorter ( P<0.001) when compared to the diazepam group. Compared with the blank control group, after intraperitoneal injection of a subthreshold dose of sodium pentobarbital, the sleep latency was significantly increased in both 1 d and 5 d hydrogen treatment groups, and there was no significant difference as compared to the diazepam group. In the 3 d hydrogen treatment group, the sleep latency was only slightly increased ( P>0.05), which was significantly lower than that of the diazepam group ( P<0.05). CONCLUSION: Low concentration hydrogen inhalation could alleviate OVA-induced asthma in mice, and the mechanism might be related to the anti-oxidative and anti-inflammatory effects of hydrogen. Also, low concentration hydrogen inhalation could improve sleep function in mice.

Chronic periodontitis induces microbiota-gut-brain axis disorders and cognitive impairment in mice.

Epidemiological studies suggest that chronic periodontitis (CP) is closely associated with the incidence and progression of cognitive impairment. The present study investigated the causal relationship between CP and cognitive decline and the underlying mechanism in mice. Long-term ligature around the left second maxillary molar tooth was used to induce CP in mice. Severe alveolar bone loss and inflammatory changes were observed in gingival tissues, accompanied by progressive cognitive deficits during a 12-month period. We also observed cerebral neuronal and synaptic injury and glial activation in this mouse model of CP. Furthermore, CP mice exhibited significant dysbiosis of the oral and gut microbiota, disruption of the intestinal barrier and blood-brain barrier, increases in the serum contents of proinflammatory cytokines and lipopolysaccharide (LPS), and increases in brain LPS levels, Toll-like receptor 4 (TLR4) expression, nuclear factor-κB (NF-κB) nuclear translocation and proinflammatory cytokine mRNA levels. These results indicate that CP may directly induce progressive cognitive decline and its mechanism is probably related to microbiota-gut-brain axis disorders, LPS/TLR4/NF-κB signaling activation and neuroinflammatory responses in mice. Therefore, the microbiota-gut-brain axis may provide the potential strategy for the prevention and treatment of CP-associated cognitive impairment.

Lentiviral vector-mediated overexpression of Klotho in the brain improves Alzheimer's disease-like pathology and cognitive deficits in mice.

Alzheimer's disease (AD) is the most common type of senile dementia. The antiaging gene Klotho is reported to decline in the brain of patients and animals with AD. However, the role of Klotho in the progression of AD remains elusive. The present study explored the effects and underlying mechanism of Klotho in a mouse model of AD. The upregulation of cerebral Klotho expression was mediated by an intracerebroventricular injection of a lentiviral vector that encoded Klotho (LV-KL) in 7-month-old amyloid precursor protein/presenilin 1 transgenic mice. Three months later, LV-KL significantly induced Klotho overexpression in the brain and effectively ameliorated cognitive deficit and AD-like pathology in amyloid precursor protein/presenilin 1 mice. LV-KL induced autophagy activation and protein kinase B/mammalian target of rapamycin inhibition both in AD mice and BV2 murine microglia. These results suggest that the upregulation of Klotho expression in the brain may promote the autophagic clearance of amyloid beta and protect against cognitive deficits in AD mice. These findings highlight the preventive and therapeutic potential of Klotho for the treatment of AD.

The neuroprotective effects and probable mechanisms of Ligustilide and its degradative products on intracerebral hemorrhage in mice.

BACKGROUND: Intracerebral hemorrhage (ICH) is a common neurological emergency with higher mortality and disability rate than cerebral ischemia. Although diverse therapeutic interventions have been explored for potential neuroprotection from ICH, no effective drugs until now are available for improvement of survival rate or the life quality of survivors after ICH. Just like cerebral ischemia, inflammatory mechanism is highly thought to play a vital role in hemorrhagic brain injury. Ligustilide (LIG) has potent anti-inflammatory effects, which were shown to be closely related to its neuroprotective effects against ischemic brain injury. Senkyunolide H (SH) and senkyunolide I (SI) are natural degradation products of LIG, which contain the mother nucleus structure of LIG as that of phthalide. However, no reports have been retrieved about the neuroprotective effects of the three phthalide compounds on ICH, especially from the perspectives of inflammatory pathways. Accordingly, this study investigated the neuroprotective potentials and mechanisms of LIG, SH and SI on experimental ICH in mice. METHODS: ICH was induced in adult male CD-1 mice by intracerebral injection of autologous blood. LIG, SH and SI, respectively, was administrated after ICH induction. Neurological deficits, brain edema, injury volume, the number of surviving/dying neurons and inflammatory gene expression were evaluated at 3 days after ICH. RESULTS: Neurological deficits, brain edema, neuronal injury, microglia and astrocytes activation as well as peripheral immune cells infiltration were all significantly improved by LIG and SH, yet SI not. Moreover, the expression of TLR4, p-NF-kB p65, TNF-α and IL-6, was significantly downregulated by LIG and SH treatment. So was Prx1 expression and release. CONCLUSIONS: LIG and SH provide the potent neuroprotective effects against hemorrhagic stroke by inhibiting Prx1/TLR4/NF-kB signaling and the subsequent immune and neuroinflammation lesions.

Lentivirus-mediated klotho up-regulation improves aging-related memory deficits and oxidative stress in senescence-accelerated mouse prone-8 mice.

AIMS: Oxidative stress caused by aging aggravates neuropathological changes and cognitive deficits. Klotho, an anti-aging protein, shows an anti-oxidative effect. The aims of the present study were to determine the potential therapeutic effect of klotho in aging-related neuropathological changes and memory impairments in senescence-accelerated mouse prone-8 (SAMP8) mice, and identify the potential mechanism of these neuroprotective effects. MATERIALS AND METHODS: A lentivirus was used to deliver and sustain the expression of klotho. The lentiviral vectors were injected into the bilateral lateral ventricles of 7-month-old SAMP8 mice or age-matched SAMR1 mice. Three months later, the Y-maze alternation task and passive avoidance task were used to assess the memory deficits of the mice. In situ hybridization, immunohistochemistry, immunofluorescence, Nissl staining, quantitative real-time PCR and Western blot assays were applied in the following research. KEY FINDINGS: Our results showed that 3 months after injection of the lentiviral vectors encoding the full-length klotho gene, the expression of klotho in the brain was significantly increased in 10-month-old SAMP8 mice. This treatment reduced memory deficits, neuronal loss, synaptic damage and 4-HNE levels but increased mitochondrial manganese-superoxide dismutase (Mn-SOD) and catalase (CAT) expression. Moreover, the up-regulation of klotho expression decreased Akt and Forkhead box class O1 (FoxO1) phosphorylation. SIGNIFICANCE: The present study provides a novel approach for klotho gene therapy and demonstrates that direct up-regulation of klotho in the brain might improve aging-related memory impairments and decrease oxidative stress. The underlying mechanism of this effect likely involves the inhibition of the Akt/FoxO1 pathway.

Klotho upregulation contributes to the neuroprotection of ligustilide against cerebral ischemic injury in mice.

Klotho, an aging-suppressor gene, encodes a protein that potentially acts as a neuroprotective factor. Our previous studies showed that ligustilide minimizes the cognitive dysfunction and brain damage induced by cerebral ischemia; however, the underlying mechanisms remain unclear. This study aims to investigate whether klotho is involved in the protective effects of ligustilide against cerebral ischemic injury in mice. Cerebral ischemia was induced by bilateral common carotid arterial occlusion. Neurobehavioral tests as well as Nissl and Fluoro-Jade B staining were used to evaluate the protective effects of ligustilide in cerebral ischemia, and Western blotting and ELISA approaches were used to investigate the underlying mechanisms. Administration of ligustilide prevented the development of neurological deficits and reduced neuronal loss in the hippocampal CA1 region and the caudate putamen after cerebral ischemia. The protective effects were associated with inhibition of the RIG-I/NF-κB p65 and Akt/FoxO1 pathways and with prevention of inflammation and oxidative stress in the brain. Further, downregulation of klotho could attenuate the neuroprotection of ligustilide against cerebral ischemic injury. Ligustilide exerted neuroprotective effects in mice after cerebral ischemia by regulating anti-inflammatory and anti-oxidant signaling pathways. Furthermore, klotho upregulation contributes to the neuroprotection of LIG against cerebral ischemic injury. These results indicated that ligustilide may be a promising therapeutic agent for the treatment of cerebral ischemia.