Cerebral ischemia-reperfusion (I/R) incites neurologic damage through a myriad of complex pathophysiological mechanisms, most notably, inflammation and oxidative stress. In I/R injury, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) produces reactive oxygen species (ROS), which promote inflammatory and apoptotic pathways, augmenting ROS production and promoting cell death. Inhibiting ischemia-induced oxidative stress would be beneficial for reducing neuroinflammation and promoting neuronal cell survival. Studies have demonstrated that chlorpromazine and promethazine (C+P) induce neuroprotection. This study investigated how C+P minimizes oxidative stress triggered by ischemic injury. Adult male Sprague-Dawley rats were subject to middle cerebral artery occlusion (MCAO) and subsequent reperfusion. 8 mg/kg of C+P was injected into the rats when reperfusion was initiated. Neurologic damage was evaluated using infarct volumes, neurological deficit scoring, and TUNEL assays. NOX enzymatic activity, ROS production, protein expression of NOX subunits, manganese superoxide dismutase (MnSOD), and phosphorylation of PKC-δ were assessed. Neural SHSY5Y cells underwent oxygen-glucose deprivation (OGD) and subsequent reoxygenation and C+P treatment. We also evaluated ROS levels and NOX protein subunit expression, MnSOD, and p-PKC-δ/PKC-δ. Additionally, we measured PKC-δ membrane translocation and the level of interaction between NOX subunit (p47phox) and PKC-δ via coimmunoprecipitation. As hypothesized, treatment with C+P therapy decreased levels of neurologic damage. ROS production, NOX subunit expression, NOX activity, and p-PKC-δ/PKC-δ were all significantly decreased in subjects treated with C+P. C+P decreased membrane translocation of PKC-δ and lowered the level of interaction between p47phox and PKC-δ. This study suggests that C+P induces neuroprotective effects in ischemic stroke through inhibiting oxidative stress. Our findings also indicate that PKC-δ, NOX, and MnSOD are vital regulators of oxidative processes, suggesting that C+P may serve as an antioxidant.
Although physical exercise has been demonstrated to augment recovery of the post-stroke brain, the question of what level of exercise intensity optimizes neurological outcomes of post-stroke rehabilitation remains unsettled. In this study, we aim to clarify the mechanisms underlying the intensity-dependent effect of exercise on neurologic function, and thereby to help direct the clinical application of exercise-based neurorehabilitation. To do this, we used a well-established rat model of ischemic stroke consisting of cerebral ischemia induction through middle cerebral artery occlusion (MCAO). Ischemic rats were subsequently assigned either to a control group entailing post-stroke rest or to one of two exercise groups distinguished by the intensity of their accompanying treadmill regimens. After 24 h of reperfusion, exercise was initiated. Infarct volume, apoptotic cell death, and neurological defects were quantified in all groups at 3 days, and motor and cognitive functions were tracked up to day-28. Additionally, Western blotting was used to assess the influence of our interventions on several proteins related to synaptogenesis and neuroplasticity (growth-associated protein 43, a microtubule-associated protein, postsynaptic density-95, synapsin I, hypoxia-inducible factor-1α, brain-derived neurotrophic factor, nerve growth factor, tyrosine kinase B, and cAMP response element-binding protein). Our results were in equal parts encouraging and surprising. Both mild and intense exercise significantly decreased infarct volume, cell death, and neurological deficits. Motor and cognitive function, as determined using an array of tests such as beam balance, forelimb placing, and the Morris water maze, were also significantly improved by both exercise protocols. Interestingly, while an obvious enhancement of neuroplasticity proteins was shown in both exercise groups, mild exercise rats demonstrated a stronger effect on the expressions of Tau (p < 0.01), brain-derived neurotrophic factor (p < 0.01), and tyrosine kinase B (p < 0.05). These findings contribute to the growing body of literature regarding the positive effects of both mild and intense long-term treadmill exercise on brain injury, functional outcome, and neuroplasticity. Additionally, the results may provide a base for our future study regarding the regulation of HIF-1α on the BDNF/TrkB/CREB pathway in the biochemical processes underlying post-stroke synaptic plasticity.
The purpose of this study was to discriminate the clinical and imaging correlates of cerebral arterial stenosis (CAS), venous stenosis (CVS) and arterio-venous stenosis (CAVS) in the clinical setting.Patients were classified into three groups: CAS (n = 75), CVS (n=74) and CAVS (n=67).Focal neurological deficits were the prominent presenting symptoms in CAS group, while venous turbulence related symptoms were common in both CVS and CAVS group.Risk factor analysis showed the OR (95%CI) for diabetes, male gender and age in CAS vs. CVS group were 13.67(2.71,68.85), 6.69(2.39,18.67) and 1.07(1.03,1.12) respectively.Male gender, diabetes and age in CAVS vs. CAS groups were 0.27(0.11,0.63), 0.26(0.10,0.67) and 1.09(1.04,1.14) respectively, while age in CAVS vs. CVS group was 1.11(1.07,1.15).The white matter lesions (WMLs) in CAS group varied in size, with clear boundaries asymmetrically distributed in bilateral hemispheres.CVS-induced WMLs revealed a bilaterally symmetric, cloudylike appearance.The cerebral perfusion was asymmetrically reduced in CAS but symmetrically reduced in CVS group.The clinical characteristics and neuroimaging presentations were different among patients with CAS, CVS and CAVS.We recommended for aged patients, both arterial and venous imaging should be considered in diagnosis of cerebral stenotic vascular disorders.
Macrophage activation plays a crucial part in synovial inflammation, a driving force in osteoarthritis (OA) [1]. Our previous research has revealed that NOD2 attenuates OA by modulating macrophage activation, while the underlying mechanism remains unclear. Palmitoylation modification has been demonstrated to be associated with NOD2 activity [2].
Objectives:
To demonstrate whether NOD2 palmitoylation contributes to the modulation of macrophage activation and, if so, to uncover the regulatory mechanisms.
Methods:
First, we explored the correlation between inflammation and NOD2 palmitoylation in human synovial tissue by immunohistochemical (IHC) staining. Additionally, we investigated the impact of palmitoylation inhibitor (2-BP) on the intracellular localization of NOD2 and the activation of bone marrow derived macrophages (BMDMs). Subsequently, potential targets that may contribute to the palmitoylation of NOD2 were screened via RNA sequencing, followed by co-immunoprecipitation (Co-IP), immunofluorescence (IF) staining, Western blotting (WB), and in vitro inhibition of specific molecule using targeted small interference RNA (si-RNA). Finally, we constructed overexpressing lentiviruses targeting ZDHHC5 (oe-ZDHHC5), established a collagenase-induced OA (CIOA) model with 8-week-old male C57BL/6J mice, and injected lentiviral vectors into the knee joint cavity as the experimental group (CIOA + oe-ZDHHC5), with the empty vectors as the control (CIOA + Mock). 8 weeks later, knee joints were harvested, and Safranin O/Fast Green and 3D reconstruction of Micro-CT images were employed to evaluate the pathological changes of OA.
Results:
IHC staining and WB of human synovial tissue indicated a negative correlation between inflammation and NOD2 palmitoylation (Figure 1A and B). Palmitoylation was necessary for the membrane recruitment of NOD2, and was inhibited by 2-BP (Figure 1C and D). Consistent with IHC findings, NOD2 palmitoylation was associated with reduced activation of BMDMs (Figure 1E and F). Bioinformatic analyses suggested two acyl-transferases, ZDHHC5 and ZDHHC12, to be potentially involved in NOD2 palmitoylation. ZDHHC5, down-regulated in osteoarthritis, was involved in the interaction with NOD2 (Figure 2A–C). Targeted inhibition of ZDHHC5 resulted in reduced palmitoylation of NOD2 and increased level of BMDM activation (Figure 2D and E). Finally, in vivo data confirmed that ZDHHC5 overexpression attenuates osteoarthritis in mice, as indicated by Osteoarthritis Research Society International (OARSI) score and osteophyte formation (Figure 2F and G).
Conclusion:
ZDHHC5 mediated the palmitoylation modification of NOD2, which was necessary for NOD2 to exert its inhibitory effect on BMDM activation, thereby attenuating OA.
REFERENCES:
[1] Zhang H, Lin C, Zeng C, Wang Z, Wang H, Lu J, et al. Synovial macrophage M1 polarisation exacerbates experimental osteoarthritis partially through R-spondin-2. Annals of the rheumatic diseases. 2018;77(10):1524-34. [2] Lu Y, Zheng Y, Coyaud E, Zhang C, Selvabaskaran A, Yu Y, et al. Palmitoylation of NOD1 and NOD2 is required for bacterial sensing. Science. 2019;366(6464):460-7.
Acknowledgements:
I would like to thanks all people who have helped and were directly or indirectly involved in this study. This work was supported by Guangdong Medical Research Foundation [A2020094], Guangdong Basic and Applied Basic Research Foundation [2021A1515110996, 2023A1515010463], and Science and Technology Project of Guangzhou [202102020132, 202206010140].
The gluconeogenesis pathway, which has been known to normally present in the liver, kidney, intestine, or muscle, has four irreversible steps catalyzed by the enzymes: pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, and glucose 6-phosphatase. Studies have also demonstrated evidence that gluconeogenesis exists in brain astrocytes but no convincing data have yet been found in neurons. Astrocytes exhibit significant 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 activity, a key mechanism for regulating glycolysis and gluconeogenesis. Astrocytes are unique in that they use glycolysis to produce lactate, which is then shuttled into neurons and used as gluconeogenic precursors for reduction. This gluconeogenesis pathway found in astrocytes is becoming more recognized as an important alternative glucose source for neurons, specifically in ischemic stroke and brain tumor. Further studies are needed to discover how the gluconeogenesis pathway is controlled in the brain, which may lead to the development of therapeutic targets to control energy levels and cellular survival in ischemic stroke patients, or inhibit gluconeogenesis in brain tumors to promote malignant cell death and tumor regression. While there are extensive studies on the mechanisms of cerebral glycolysis in ischemic stroke and brain tumors, studies on cerebral gluconeogenesis are limited. Here, we review studies done to date regarding gluconeogenesis to evaluate whether this metabolic pathway is beneficial or detrimental to the brain under these pathological conditions.
Asymptomatic coronary artery stenosis (ACAS) ≥50% is common in patients with acute ischemic cerebrovascular disease (AICVD), which portends a poor cardiovascular and cerebrovascular prognosis. Identifying ACAS ≥50% early may optimize the clinical management and improve the outcomes of these high-risk AICVD patients. This study aimed to investigate whether aortic arch plaque (AAP), an early atherosclerotic manifestation of brain blood-supplying arteries, could be a predictor for ACAS ≥50% in AICVD.In this cross-sectional study, atherosclerosis of the coronary and brain blood-supplying arteries was simultaneously evaluated using one-step computed tomography angiography (CTA) in AICVD patients without coronary artery disease history. The patients were divided into ACAS ≥50% and non-ACAS ≥50% groups according to whether CTA showed stenosis ≥50% in at least one coronary arterial segment. The AAP characteristics of CTA were depicted from aspects of thickness, extent, and complexity.Among 118 analyzed patients with AICVD, 29/118 (24.6%) patients had ACAS ≥50%, while AAPs were observed in 86/118 (72.9%) patients. Increased AAP thickness per millimeter (adjusted odds ratio [OR]: 1.56, 95% confidence interval [CI]: 1.18-2.05), severe-extent AAP (adjusted OR: 13.66, 95% CI: 2.33-80.15), and presence of complex AAP (adjusted OR: 7.27, 95% CI: 2.30-23.03) were associated with ACAS ≥50% among patients with AICVD, independently of clinical demographics and cervicocephalic atherosclerotic stenosis. The combination of AAP thickness, extent, and complexity predicted ACAS ≥50% with an area under the receiver-operating characteristic curve of 0.78 (95% CI: 0.70-0.85, P < 0.001). All three AAP characteristics provided additional predictive power beyond cervical and intracranial atherosclerotic stenosis for ACAS ≥50% in AICVD (all P < 0.05).Thicker, severe-extent, and complex AAP were significant markers of the concomitant ACAS ≥50% in AICVD, possibly superior to the indicative value of cervical and intracranial atherosclerotic stenosis. As an integral part of atherosclerosis of brain blood-supplying arteries, AAP should not be overlooked in predicting ACAS ≥50% for patients with AICVD.
There has been both great interest in and skepticism about the strategies for headache inhibition in patients with patent foramen ovale and migraines (PFO-migraine). Furthermore, many questions remain about the fundamental pathophysiology of PFO-migraines. Herein, the inhibiting effect of normobaric oxygenation (NBO) on PFO-migraine was analyzed.This real-world self-control study consecutively enrolled patients during the ictal phase of migraines who had patent foramen ovale (PFO) confirmed by Trans esophageal Ultrasound(TEE). After comparing the baseline arterial oxygen partial pressure (PaO2) in their blood gas with that of healthy volunteers, all the patients with PFO-migraine underwent treatment with NBO (8 L/min. for 1 h/q8h) inhalation through a mask. Their clinical symptoms, blood gas, and electroencephalograph (EEG) prior to and post-NBO were compared.A total of 39 cases with PFO-migraine (in which 36% of participants only had a small-aperture of PFO) and 20 non-PFO volunteers entered the final analysis. Baseline blood gas analysis results showed that the PaO2 in patients with PFO-migraine were noticeably lower than PaO2 levels in non-PFO volunteers. After all patients with PFO-migraines underwent NBO treatment, 29(74.4%) of them demonstrated dramatic headache attenuation and a remarkable increase in their arterial PaO2 levels after one time treatment of NBO inhalation (p < 0.01). The arterial PaO2 levels in these patients gradually went down during the following 4 h after treatment. 5 patients finished their EEG scans prior to and post-NBO, and 4(80%) were found to have more abnormal slow waves in their baseline EEG maps. In the follow up EEG maps post-NBO treatment for these same 4 patients, the abnormal slow waves disappeared remarkably.Patients with PFO-migraine may derive benefit from NBO treatment. PFOs result in arterial hypoxemia due to mixing of venous blood, which ultimately results in brain hypoxia and migraines. This series of events may be the key pathologic link explaining how PFOs lead to migraines. NBO use may attenuate the headaches from migraines by correcting the hypoxemia.
Introduction: Hyperglycolysis, the increase in glucose uptake and metabolism relative to the rate of oxygen utilization, is detrimental because of uncoupling of glycolysis, oxidative phosphorylation and thus lactic acidosis. Therapeutic hypothermia (TH) is one of the most effective neuroprotectants against ischemic injury. However, its clinical use in stroke is restricted due to slow onset, extensive medical and nursing efforts, and complications. Pharmacological hypothermia is an important alternative to induce TH. DHC is a powerful hypothermia inducing agent that targets brain thermoregulation. However, the complications associated with a high dose for achieving TH limited its use. Previous study has showed that C+P decreased brain activity and body temperature. We aimed to establish a therapeutic strategy of synergistic TH for faster cooling and stronger neuroprotection. Methods: Sprague-Dawley rats were subjected to 2 h middle cerebral artery occlusion (MCAO) and 6 or 24 h reperfusion, upon which rats intraperitoneally received very low dose of C+P (4 mg/kg), DHC (0.5 mg/kg) or their combination, or inhibitors of glucose transporter 1 and 3 (GLU1/3) (phloretin/cyclin B). Infarct volumes and neurological deficits were examined. Oxidative injury was determined by levels of ATP, lactate, and reactive oxygen species (ROS). Hyperglycolysis was determined by brain glucose, as well as the protein levels of GLUT1, GLUT3, PFK and LDH. Results: Body temperature reached the lowest target at 36.5°C by DHC, 35.2°C by C+P, 34°C by combination. Following 6 and 24 h of reperfusion, combination therapy exhibited greater reduction of infarct volume, neurological deficit, brain glucose, lactate and ROS levels, but increased ATP compared to monotherapy. Meanwhile, both DHC and C+P monotherapies reduced GLUT1, GLUT3, PFK and LDH expression, and the reduced expression of these proteins was enhanced by combination therapy. Inhibition of GLUT1 and GLUT3 showed similar trend as the combination therapy group. Conclusion: The combination of C+P and DHC enhances the efficiency of TH and efficacy of TH-induced neuroprotection in ischemic stroke. This may be mediated by inhibiting glucose metabolism and associated hyperglycolysis.
Accumulating evidence has demonstrated that post-stroke physical rehabilitation may reduce morbidity. The effectiveness of post-stroke exercise, however, appears to be contingent upon exercise initiation. This study assessed the hypothesis that very early exercise exacerbates brain injury, induces reactive oxygen species (ROS) generation, and promotes energy failure. A total of 230 adult male Sprague-Dawley rats were subjected to middle cerebral artery (MCA) occlusion for 2 h, and randomized into eight groups, including two sham injury control groups, three non-exercise and three exercise groups. Exercise was initiated after 6 h, 24 h and 3 days of reperfusion. Twenty-four hours after completion of exercise (and at corresponding time points in non-exercise controls), infarct volumes and apoptotic cell death were examined. Early brain oxidative metabolism was quantified by examining ROS, ATP and NADH levels 0.5 h after completion of exercise. Furthermore, protein expressions of angiogenic growth factors were measured in order to determine whether post-stroke angiogenesis played a role in rehabilitation. As expected, ischemic stroke resulted in brain infarction, apoptotic cell death and ROS generation, and diminished NADH and ATP production. Infarct volumes and apoptotic cell death were enhanced (p < 0.05) by exercise that was initiated after 6 h of reperfusion, but decreased by late exercise (24 h, 3 days). This exacerbated brain injury at 6 h was associated with increased ROS levels (p < 0.05), and decreased (p < 0.05) NADH and ATP levels. In conclusion, very early exercise aggravated brain damage, and early exercise-induced energy failure with ROS generation may underlie the exacerbation of brain injury. These results shed light on the manner in which exercise initiation timing may affect post-stroke rehabilitation.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
