scholarly journals NAD+ improves cognitive function and reduces neuroinflammation by ameliorating mitochondrial damage and decreasing ROS production in chronic cerebral hypoperfusion models through Sirt1/PGC-1α pathway

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yao Zhao ◽  
Jiawei Zhang ◽  
Yaling Zheng ◽  
Yaxuan Zhang ◽  
Xiao Jie Zhang ◽  
...  

Abstract Background Microglial-mediated neuroinflammation plays an important role in vascular dementia, and modulating neuroinflammation has emerged as a promising treatment target. Nicotinamide adenine dinucleotide (NAD+) shows anti-inflammatory and anti-oxidant effects in many neurodegenerative disease models, but its role in the chronic cerebral hypoperfusion (CCH) is still unclear. Methods The bilateral common carotid artery occlusion (BCCAO) was performed to establish CCH models in Sprague-Dawley rats. The rats were given daily intraperitoneal injection of NAD+ for 8 weeks. The behavioral test and markers for neuronal death and neuroinflammation were analyzed. Mitochondrial damage and ROS production in microglia were also assessed. RNA-seq was performed to investigate the mechanistic pathway changes. For in vitro studies, Sirt1 was overexpressed in BV2 microglial cells to compare with NAD+ treatment effects on mitochondrial injury and neuroinflammation. Results NAD+ administration rescued cognitive deficits and inhibited neuroinflammation by protecting mitochondria and decreasing ROS production in CCH rats. Results of mechanistic pathway analysis indicated that the detrimental effects of CCH might be associated with decreased gene expression of PPAR-γ co-activator1α (PGC-1α) and its upstream transcription factor Sirt1, while NAD+ treatment markedly reversed their decrease. In vitro study confirmed that NAD+ administration had protective effects on hypoxia-induced neuroinflammation and mitochondrial damage, as well as ROS production in BV2 microglia via Sirt1/PGC-1α pathway. Sirt1 overexpression mimicked the protective effects of NAD+ treatment in BV2 microglia. Conclusions NAD+ ameliorated cognitive impairment and dampened neuroinflammation in CCH models in vivo and in vitro, and these beneficial effects were associated with mitochondrial protection and ROS inhibition via activating Sirt1/PGC-1α pathway.

2021 ◽  
Author(s):  
Yao Zhao ◽  
Jiawei Zhang ◽  
Yaling Zheng ◽  
Yaxuan Zhang ◽  
Xiaojie Zhang ◽  
...  

Abstract Background: Microglial mediated neuroinflammation plays an important role in vascular dementia, and modulating neuroinflammation has emerged as a promising treatment target. NAD + shows anti-inflammatory and anti-oxidant effects in many neurodegenerative disease models, but its role in the chronic cerebral hypoperfusion (CCH) is still unclear. Methods: The bilateral common carotid artery occlusion (BCCAO) was performed to establish CCH models in Sprague-Dawley rats. The rats were given daily intraperitoneal injection of NAD + for 8 weeks. Behavioral test and markers for neuronal death and neuroinflammation were analyzed. Mitochondrial damage and ROS production in microglia were also assessed. RNA-seq was performed to investigate the mechanistic pathway changes. For in vitro studies, Sirt1 was overexpressed in BV2 microglial cells to compare with NAD + treatment effects on mitochondrial injury and neuroinflammation. Results: NAD + administration rescued cognitive deficits and inhibited neuroinflammation by protecting mitochondria and decreasing ROS production in CCH rats. Results of mechanistic pathway analysis indicated that the detrimental effects of CCH might be associated with decreased gene expression of PPAR-γ co-activator1α (PGC-1α) and its upstream transcription factor Sirt1 , while NAD + treatment markedly reversed their decrease. In vitro study confirmed that NAD + administration had protective effects on hypoxia induced neuroinflammation and mitochondrial damage, as well as ROS production in BV2 microglia via Sirt1/PGC-1α pathway. Sirt1 overexpression mimicked the protective effects of NAD + treatment in BV2 microglia.Conclusions: NAD + ameliorated cognitive impairment and dampened neuroinflammation in CCH models in vivo and vitro, and these beneficial effects were associated with mitochondrial protection and ROS inhibition via activating Sirt1/PGC-1α pathway. Keywords: Chronic cerebral hypoperfusion, microglia, NAD + , mitochondria, ROS


2020 ◽  
Author(s):  
Yaling Zheng ◽  
Jiawei Zhang ◽  
Yao Zhao ◽  
Yaxuan Zhang ◽  
Xiaojie Zhang ◽  
...  

Abstract BackgroundChronic cerebral hypoperfusion (CCH) is regarded as a high-risk factor for cognitive decline in vascular dementia (VaD). We have previously shown that diabetes mellitus (DM) synergistically promotes CCH-induced cognitive dysfunction via exacerbating neuroinflammation. Furthermore, curcumin has been shown to exhibit anti-inflammatory and neuroprotective activities. However, the effects of curcumin on CCH-induced cognitive impairments in DM have remained unknown.MethodsRats were fed with a high-fat diet (HFD) and injected with low-dose streptozotocin (STZ), followed by bilateral common carotid artery occlusion (BCCAO), to model DM and CCH in vivo. After BCCAO, curcumin (50 mg/kg) was administered intraperitoneally every two days for eight weeks to evaluate its therapeutic effects. Additionally, mouse BV2 microglial cells were exposed to hypoxia and high glucose to model CCH and DM pathologies in vitro. ResultsCurcumin treatment significantly improved DM/CCH-induced cognitive deficits and attenuated neuronal cell death. Molecular analysis revealed that curcumin exerted protective effects via suppressing neuroinflammation induced by microglial activation, regulating the triggering receptor expressed on myeloid cells 2 (TREM2)/toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway, alleviating apoptosis, and reducing nod-like receptor protein 3 (NLRP3)-dependent pyroptosis.ConclusionsTaken together, our findings suggest that curcumin represents a promising therapy for DM/CCH-induced cognitive impairments.


2021 ◽  
Vol 4 (2) ◽  
pp. 1-13
Author(s):  
Kesevan Rajah Kumaran ◽  
Habibah Abdul Wahab ◽  
Zurina Hassan

Vascular dementia (VaD), is one of the most common types of dementia in the ageing population, initiated by chronic cerebral hypoperfusion (CCH). At present, effective therapeutic approaches to cure VaD are still missing. Cholinergic system dysfunction in the central nervous system (CNS) has been recognised as one of the main reasons for learning and memory impairment in VaD patients. Therefore, medications that restore the level of acetylcholine (ACh) neurotransmitter by inhibiting cholinesterase activity were proposed as a potential candidate to treat VaD patients. Permanent occlusion of bilateral common carotid arteries (POBCCA) surgery method was performed to develop CCH model in rats. The present study evaluated the anti-cholinesterase activity of three Malaysian plant methanol leaf extracts in vitro and further validated its cognitive-enhancing effects in vivo using POBCCA rats. The selected plant extracts were Coccoloba uvifera (stems), Mimusops elengi (leaves) and Syzygium aqueum (leaves). The in vitro anti-cholinesterase activities of these plants were determined using Ellman's method. The effects of selected plant extracts (100 and 200 mg/kg, p.o.) on learning and memory functions were evaluated using a series of behavioural tests. All the selected plant extracts exhibited good anti-acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities in vitro, with IC50 ranging from 3.67 to 16.04 and 5.6 to 13.95 µg/mL, respectively. Extracts of S. aqueum (200 mg/kg) improve both short- and long-term recognition memories, whereas M. elengi and S. aqueum (200 mg/kg) extracts improve spatial learning. None of the extracts impaired motor and exploratory functions in POBCCA rats. In conclusion, methanol extracts of C. uvifera, M. elengi and S. aqueum showed good anti-cholinesterase activity in vitro. However, only M. elengi and S. aqueum improve learning and memory function in POBCCA rats.


2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Dongdong Yuan ◽  
Xiaoyun Li ◽  
Chenfang Luo ◽  
Xianlong Li ◽  
Nan Cheng ◽  
...  

Abstract Postoperative acute kidney injury (AKI) is a severe complication after liver transplantation (LT). Its deterioration and magnification lead to the increase in mortality. Connexin43 (Cx43) mediates direct transmission of intracellular signals between neighboring cells, always considered to be the potent biological basis of organ damage deterioration and magnification. Thus, we explored the effects of Cx43 on AKI following LT and its related possible mechanism. In this study, alternations of Cx43 expression were observed in 82 patients, receiving the first-time orthotopic LT. We built autologous orthotopic liver transplantation (AOLT) models with Sprague–Dawley (SD) rats in vivo, and hypoxia-reoxygenation (H/R) or lipopolysaccharide (LPS) pretreatment models with kidney tubular epithelial cells (NRK-52E) in vitro, both of which were the most important independent risk factors of AKI following LT. Then, different methods were used to alter the function of Cx43 channels to determine its protective effects on AKI. The results indicated that patients with AKI suffering from longer time of tracheal intubation or intensive care unit stay, importantly, had significantly lower survival rate at postoperative 30 days and 3 years. In rat AOLT models, as Cx43 was inhibited with heptanol, postoperative AKI was attenuated significantly. In vitro experiments, downregulation of Cx43 with selective inhibitors, or siRNA protected against post-hypoxic NRK-52E cell injuries caused by H/R and/or LPS, while upregulation of Cx43 exacerbated the above-mentioned cell injuries. Of note, alternation of Cx43 function regulated the content of reactive oxygen species (ROS), which not only mediated oxidative stress and inflammation reactions effectively, but also regulated necroptosis. Therefore, we concluded that Cx43 inhibition protected against AKI following LT through attenuating ROS transmission between the neighboring cells. ROS alternation depressed oxidative stress and inflammation reaction, which ultimately reduced necroptosis. This might offer new insights for targeted intervention for organ protection in LT, or even in other major surgeries.


Author(s):  
Qilong Zhang ◽  
Zhijia Fan ◽  
wei xue ◽  
Fanfan Sun ◽  
Huaqing Zhu ◽  
...  

Chronic cerebral hypoperfusion (CCH), as a critical factor of chronic cerebrovascular diseases, has greatly influenced the health of patients with vascular dementia (VD). The putative protective effects of vitexin on the CCH need further investigations. In the current study, the role of vitexin and its underlying mechanism were investigated with permanent bilateral common carotid artery occlusion (2VO) in rats as well as HT22 cells with OGD/R injury model. The results demonstrated that vitexin improved cognitive dysfunction as well as alleviated pathological neuronal damage in HE and TUNEL results. The decreased levels of Epac1, Epac2, Rap1 and p-ERK were reversed by vitexin in rats with CCH. Furthermore, this study indicated that vitexin alleviated CCH-induced inflammation injuries by reducing the expression of NLRP3, Caspase-1, IL-1β, IL-6, and cleaved Caspase-3. In vitro, vitexin increased the expression of Epac1 and Epac2, decreased the activation of the NLRP3-mediated inflammation, and improved cell viability. Taken together, our findings suggest that vitexin can reduce the degree of the progressing pathological damage in the cortex and hippocampus and inhibit further deterioration of cognitive function in rats with CCH. Epac and NLRP3 can be regulated by vitexin, which provides enlightenment for the protection of CCH injury.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yan Liu ◽  
Xiaobo Huang ◽  
Wenqiang Chen ◽  
Yujing Chen ◽  
Ningqun Wang ◽  
...  

Chronic cerebral hypoperfusion (CCH) is closely related to the occurrence of Alzheimer’s disease (AD) in the elderly. CCH can induce overactivation of autophagy, which increases the deposition of amyloid-β (Aβ) plaques in the brain, eventually impairing the cognitive function. Yuan-Zhi decoction (YZD) is a traditional Chinese medicine (TCM) formulation that is used to treat cognitive dysfunction in the elderly, but the specific mechanism is still unclear. In this study, we simulated CCH in a rat model through bilateral common carotid artery occlusion (BCCAO) and treated the animals with YZD. Standard neurological tests indicated that YZD significantly restored the impaired cognitive function after BCCAO in a dose-dependent manner. Furthermore, YZD also decreased the levels of Aβ aggregates and the autophagy-related proteins ATG5 and ATG12 in their hippocampus. An in vitro model of CCH was also established by exposing primary rat hippocampal neurons to hypoxia and hypoglycemia (H-H). YZD and its active ingredients increased the survival of these neurons and decreased the levels of Aβ1-40 and Aβ1-42, autophagy-related proteins Beclin-1 and LC3-II, and the APP secretases BACE1 and PS-1. Finally, both Aβ aggregates showed a positive statistical correlation with the expression levels of the above proteins. Taken together, YZD targets Aβ, autophagy, and APP-related secretases to protect the neurons from hypoxic-ischemic injury and restore cognitive function.


2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Jiawei Zhang ◽  
Yu Liu ◽  
Yaling Zheng ◽  
Yan Luo ◽  
Yu Du ◽  
...  

Abstract Background Diabetes mellitus (DM) and chronic cerebral hypoperfusion(CCH)are both risk factors for cognitive impairment. However, whether DM and CCH can synergistically promote cognitive impairment and the related pathological mechanisms remain unknown. Methods To investigate the effect of DM and CCH on cognitive function, rats fed with high-fat diet (HFD) and injected with low-dose streptozotocin (STZ) followed by bilateral common carotid artery occlusion (BCCAO) were induced to mimic DM and CCH in vivo and mouse BV2 microglial cells were exposed to hypoxia and/or high glucose to mimic CCH complicated with DM pathologies in vitro. To further explore the underlying mechanism, TREM-2-specific small interfering RNA and TREM-2 overexpression lentivirus were used to knock out and overexpress TREM-2, respectively. Results Cognitive deficits, neuronal cell death, neuroinflammation with microglial activation, and TREM-2-MAPK signaling were enhanced when DM was superimposed on CCH both in vivo and in vitro. Manipulating TREM-2 expression levels markedly regulated the p38 MAPK signaling and the inflammatory response in vitro. TREM-2 knockout intensified while TREM-2 overexpression suppressed the p38 MAPK signaling and subsequent pro-inflammatory mediator production under high glucose and hypoxia condition. Conclusions These results suggest that TREM-2 negatively regulates p38 MAPK-mediated inflammatory response when DM was synergistically superimposed on CCH and highlight the importance of TREM-2 as a potential target of immune regulation in DM and CCH.


2021 ◽  
Author(s):  
li'an Huang ◽  
Wenxian Li ◽  
Di Wei ◽  
Zheng Zhu ◽  
Shuqin Zhan ◽  
...  

Abstract Background Chronic cerebral hypoperfusion (CCH) is common in multiple central nervous system diseases that are associated with neuronal death and cognitive impairment. Microglial activation-mediated polarization changes may be involved in CCH-induced neuronal damage. Adiponectin (APN) is a fat-derived plasma protein that affects neuroprotection. This study investigated whether a recombinant APN peptide (APN-P) improved the cognitive function of CCH rats by regulating microglial polarization in the cortex. Methods A CCH rat model was established through bilateral common carotid artery occlusion (BCCAO) surgery. An antibody microarray was used to analyze differentially expressed proteins in the cerebral cortex of CCH rats compared to the sham rats. APN-P and a solvent control were used to intervene at different time points. Western blotting and immunofluorescence staining were conducted to examine the status of microglial polarization in different treatment groups. qRT-PCR was used to detect the expression levels of inflammatory and anti-inflammatory genes. Neuronal morphology was assessed via Nissl staining, and cognitive function was assessed with the Morris water maze test. In vitro , by inhibiting the expression of NF-κB in BV2 microglia and using Transwell co-culture systems of BV2 microglia and neurons, the effects of APN-P on neuroprotection and the underlying mechanism were investigated. Results In the cortical microglia of 12-week-old CCH rats, the expression of APN protein was significantly downregulated compared to the sham rats. CCH damages neurons and activates cortical microglial polarization to an M1-type by upregulating inflammatory factors. APN-P supplementation upregulated APN expression in cortical microglia, with neuronal survival as well as microglial polarization from an M1 toward an M2 phenotype in CCH cortex. In vivo and in vitro experiments revealed that APN-P promoted the expression of anti-inflammatory factors and neuronal survival by inhibiting NF-κB signaling, thus improving the cognitive function in CCH rats. Conclusions Our study revealed a novel mechanism by which APN-P suppresses the NF-κB pathway and promotes microglial polarization from M1 toward the M2-type to reduce neuron damage in the cortex after CCH.


2020 ◽  
Author(s):  
Li Wang ◽  
Yadong Yuan ◽  
Xiaowei Gong ◽  
Jianjun Mao

Abstract Background: SIRT1 has anti-proliferation effects on cells through regulating the expression and activity of FOXOs. Estrogen (E2) has protective effects against hypoxic pulmonary hypertension (HPH), but the involvement of SIRT1 and FOXOs in the proliferation of pulmonary artery smooth muscle cells (PASMCs) and contribution to the effects of E2 on HPH are poorly understood. To use E2 to explore the roles of SIRT1 and FOXO3a in the pathogenesis and progression of HPH and pulmonary vascular remodeling (PVR) in vivo and in vitro.Methods: Female Sprague-Dawley rats with bilateral ovariectomy were randomized to normoxia, normoxia+E2, hypoxia, and hypoxia+E2. Serum E2 levels, hemodynamic, and pulmonary vascular pathomorphology were assessed. The anti-proliferation effect of E2 was determined in human PASMCs under hypoxia/normoxia. Immunohistochemistry, western blotting, and real-time PCR were used to assess SIRT1, FOXO3a, and PCNA in rat pulmonary artery and hPASMCs. SIRT1 activity was assayed.Results: Hypoxia increased mean pulmonary artery pressure (mPAP), medial width of pulmonary arterioles, right ventricular hypertrophy index (RVHI), decreased expression SIRT1 and FOXO3a and increased PCNA expression in rats; E2 alleviated these changes. In vitro, E2 significantly inhibited hypoxia-induced hPASMCs proliferation, associated with improvements in SIRT1 and FOXO3a expression, consistent with the in vivo results. SIRT1 inhibition attenuated the effects of E2 on hPASMCs proliferation and the expression of FOXO3a. A SIRT1 activator mimicked the effects of E2 on hPASMCs proliferation and the expression of FOXO3a.Conclusions: Upregulation of SIRT1 and FOXO3a contributes to the protective role of estrogen on HPH in rats, as supported by in vitro results using hPASMCs.


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