Targeting Transcription Factor Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) for the Intervention of Vascular Cognitive Impairment and Dementia

Interplay Between Vascular Dysfunction and Neurodegenerative Pathology: New Insights into Molecular Mechanisms and Management

Vascular dysfunction frequently coexists with neurodegenerative disorders such as dementia and Alzheimer's disease (AD) in older individuals; however, the cause-and-effect relationship remains unclear. While AD is primarily characterized by neural tissue degeneration, emerging evidence suggests that aging-induced vascular dysfunction contributes to both the onset and progression of cognitive impairment and dementia by decreasing cerebral blood flow (CBF) and disrupting the blood-brain barrier (BBB). This challenges the traditional notion and underscores vascular dysfunction as an early pathogenic stimulus; thus, targeting vascular pathologies could be a promising strategy to slow dementia progression and potentially prevent AD. Conversely, aging-related neurodegeneration exacerbates vascular dysfunction, accelerating dementia pathology through oxidative stress and inflammation as well as deposition of neurotoxic substances such as beta-amyloid (Aβ) and tau in vascular walls. This bidirectional interaction creates a vicious cycle that worsens cognitive decline, underscoring the complexity of these diseases. This review aims to highlight recent advances in research on the mechanisms of aging-related vascular dysfunction in neurodegenerative diseases, focusing on vascular contributions to cognitive impairment and dementia (VCID) and AD. Additionally, we will explore the reciprocal effects and intricate relationship between vascular dysfunction and neurodegenerative pathologies, enhancing our understanding of relative disease pathogenesis and guiding the development of innovative prevention and treatment strategies.

Brain-wide cell-type-specific transcriptomic signatures of healthy ageing in mice

Biological ageing can be defined as a gradual loss of homeostasis across various aspects of molecular and cellular function1,2. Mammalian brains consist of thousands of cell types3, which may be differentially susceptible or resilient to ageing. Here we present a comprehensive single-cell RNA sequencing dataset containing roughly 1.2 million high-quality single-cell transcriptomes of brain cells from young adult and aged mice of both sexes, from regions spanning the forebrain, midbrain and hindbrain. High-resolution clustering of all cells results in 847 cell clusters and reveals at least 14 age-biased clusters that are mostly glial types. At the broader cell subclass and supertype levels, we find age-associated gene expression signatures and provide a list of 2,449 unique differentially expressed genes (age-DE genes) for many neuronal and non-neuronal cell types. Whereas most age-DE genes are unique to specific cell types, we observe common signatures with ageing across cell types, including a decrease in expression of genes related to neuronal structure and function in many neuron types, major astrocyte types and mature oligodendrocytes, and an increase in expression of genes related to immune function, antigen presentation, inflammation, and cell motility in immune cell types and some vascular cell types. Finally, we observe that some of the cell types that demonstrate the greatest sensitivity to ageing are concentrated around the third ventricle in the hypothalamus, including tanycytes, ependymal cells, and certain neuron types in the arcuate nucleus, dorsomedial nucleus and paraventricular nucleus that express genes canonically related to energy homeostasis. Many of these types demonstrate both a decrease in neuronal function and an increase in immune response. These findings suggest that the third ventricle in the hypothalamus may be a hub for ageing in the mouse brain. Overall, this study systematically delineates a dynamic landscape of cell-type-specific transcriptomic changes in the brain associated with normal ageing that will serve as a foundation for the investigation of functional changes in ageing and the interaction of ageing and disease.

Zhongfeng Xingnao Liquid ameliorates post-stroke cognitive impairment through sirtuin1 (SIRT1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway

The activation of the sirtuin1 (SIRT1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway has been shown to mitigate oxidative stress-induced apoptosis and mitochondrial damage by reducing reactive oxygen species (ROS) levels. Clinical trials have demonstrated that Zhongfeng Xingnao Liquid (ZFXN) ameliorates post-stroke cognitive impairment (PSCI). However, the underlying mechanism, particularly whether it involves protecting mitochondria and inhibiting apoptosis through the SIRT1/Nrf2/HO-1 pathway, remains unclear. This study employed an oxygen-glucose deprivation (OGD) cell model using SH-SY5Y cells and induced PSCI in rats through modified bilateral carotid artery ligation (2VO). The effects of ZFXN on learning and memory, neuroprotective activity, mitochondrial function, oxidative stress, and the SIRT1/Nrf2/HO-1 pathway were evaluated both in vivo and in vitro. Results indicated that ZFXN significantly increased the B-cell lymphoma 2 (Bcl2)/Bcl2-associated X (Bax) ratio, reduced terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL)+ cells, and markedly improved cognition, synaptic plasticity, and neuronal function in the hippocampus and cortex. Furthermore, ZFXN exhibited potent antioxidant activity, evidenced by decreased ROS and malondialdehyde (MDA) content and increased superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels. ZFXN also demonstrated considerable enhancement of mitochondrial membrane potential (MMP), Tom20 fluorescence intensity, adenosine triphosphate (ATP) and energy charge (EC) levels, and mitochondrial complex I and III activity, thereby inhibiting mitochondrial damage. Additionally, ZFXN significantly increased SIRT1 activity and elevated SIRT1, nuclear Nrf2, and HO-1 levels. Notably, these effects were substantially counteracted when SIRT1 was suppressed by the inhibitor EX-527 in vitro. In conclusion, ZFXN alleviates PSCI by activating the SIRT1/Nrf2/HO-1 pathway and preventing mitochondrial damage.

Protective Role of Electroacupuncture Against Cognitive Impairment in Neurological Diseases

Many neurological diseases can lead to cognitive impairment in patients, which includes dementia and mild cognitive impairment and thus create a heavy burden both to their families and public health. Due to the limited effectiveness of medications in treating cognitive impairment, it is imperative to develop alternative treatments. Electroacupuncture (EA), a required method for Traditional Chinese Medicine, has the potential treatment of cognitive impairment. However, the molecular mechanisms involved have not been fully elucidated. Considering the current research status, preclinical literature published within the ten years until October 2022 was systematically searched through PubMed, Web of Science, MEDLINE, Ovid, and Embase. By reading the titles and abstracts, a total of 56 studies were initially included. It is concluded that EA can effectively ameliorate cognitive impairment in preclinical research of neurological diseases and induce potentially beneficial changes in molecular pathways, including Alzheimer's disease, vascular cognitive impairment, chronic pain, and Parkinson's disease. Moreover, EA exerts beneficial effects through the same or diverse mechanisms for different disease types, including but not limited to neuroinflammation, neuronal apoptosis, neurogenesis, synaptic plasticity, and autophagy. However, these findings raise further questions that need to be elucidated. Overall, EA therapy for cognitive impairment is an area with great promise, even though more research regarding its detailed mechanisms is warranted.

Asperuloside as a Novel NRF2 Activator to Ameliorate Endothelial Dysfunction in High Fat Diet-Induced Obese Mice

Aims: Current treatments are inadequate in alleviating obesity-associated vascular diseases. The development of effective therapies to ameliorate endothelial dysfunction and attenuate oxidative stress is of utmost importance. Asperuloside (ASP), a bioactive compound extracted from Eucommia species, exhibits antiobesity properties. However, the effects of ASP on vasculopathy have not been investigated. Therefore, the effects of ASP on vascular dysfunction and related mechanisms were elucidated. Results: ASP significantly reversed the impaired endothelium-dependent relaxations (EDRs) in obese mice and interleukin (IL)-1β-treated aortas. ASP suppressed endothelial activation in obese mice aortas and IL-1β-treated endothelial cells. ASP attenuated oxidative stress, scavenged mitochondrial reactive oxygen species (ROS), and upregulated heme oxygenase-1 (HO-1) expression in endothelium, independent of its anti-inflammatory properties. HO-1 knockdown diminished the protective effects of ASP against impaired EDRs, ROS overproduction, and endothelial activation. Endothelial cell-specific nuclear factor erythroid 2-related factor 2 (Nrf2) knockdown eliminated the ASP-mediated vascular protective effects and endothelial HO-1 upregulation, emphasizing that ASP improves endothelial function by activating Nrf2/HO-1 signaling. ASP facilitated Nrf2 nuclear translocation and the direct binding of Nrf2 to antioxidant response element, thereby enhancing HO-1 transcription and scavenging ROS. The cellular thermal shift assay results provide the first experimental characterization of the direct binding of ASP to Nrf2. Conclusions: These findings demonstrate that ASP ameliorates obesity-associated endothelial dysfunction by activating Nrf2/HO-1 signaling and thereby maintaining redox hemostasis, suggesting its potential as a novel Nrf2-targeted therapeutic agent and dietary supplement for vasculopathy. Antioxid. Redox Signal. 42, 77-96.

Isoamericanin A ameliorates neuronal damage and alleviates vascular cognitive impairments by inhibiting oxidative stress through activation of the Nrf2 pathway

Oxidative stress is critically involved in the cognitive dysfunction and neuronal progressive degeneration in the vascular cognitive impairment (VCI). The natural lignan molecular isoamericanin A (ISOA) containing multiple hydroxyl groups has great potential for suppressing oxidative stress in VCI. The primary objective of this study was to delve into the pharmacological properties of ISOA against VCI, as well as to elucidate the mechanisms driving this effect from the perspective of antioxidative stress. Transient bilateral common carotid arteries occlusion (tBCCAO) mice model and hydrogen peroxide (H2O2) treated N2a cells were employed in vivo and in vitro, respectively. Behavioral tests showed that ISOA (5, 10 mg/kg) treatment alleviated learning, memorizing, and recognition in tBCCAO model mice. ISOA alleviated the neuronal damages by increasing the number of NeuN-positive cells, decreasing the TUNEL-positive cells density, up-regulating MAP-2 expression, lighting the damage of neuronal nucleus and synapse. Mechanistically, we found that ISOA reduced the oxidative stress in neurons, which manifested by reduction on the expressions of superoxide, H2O2, intercellular reactive oxygen species (ROS) and malondialdehyde (MDA) level, and up-regulations on the expressions of anti-oxidant enzymes superoxide dismutase, heme oxygenase-1, glutathione peroxidase 4, glutathione, and NAD(P)H: quinone oxidoreductase 1. Further investigation showed that ISOA activated nuclear factor erythroid 2-related factor 2 (Nrf2) pathway by downregulating the expression of kelch-like ECH-associated protein 1, upregulating the nuclear translocation and expression of Nrf2, and augmenting antioxidant response elements (ARE) promotor activity. The ISOA-mediated promotion on ARE promotor activity and anti-oxidant enzymes expressions, and suppression on superoxide and ROS expressions and MDA levels were weakened by pharmacological inhibition or genetic knockdown of Nrf2. These effects were enhanced after knockdown Keap1 in H2O2-treated cells. Our study demonstrates that ISOA alleviates the cognitive impairments and neuronal loss in VCI by attenuating oxidative stress through promoting the activation of Nrf2 pathway.

Role of NRF2 in Pathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is a polygenic, multifactorial neurodegenerative disorder and remains the most prevalent form of dementia, globally. Despite decades of research efforts, there is still no effective cure for this debilitating condition. AD research has increasingly focused on transcription factor NRF2 (nuclear factor erythroid 2-related factor 2) as a potential therapeutic target. NRF2 plays a crucial role in protecting cells and tissues from environmental stressors, such as electrophiles and reactive oxygen species. Recently, an increasing number of studies have demonstrated that NRF2 is a key regulator in AD pathology. NRF2 is highly expressed in microglia, resident macrophages in the central nervous system, and contributes to neuroinflammation, phagocytosis and neurodegeneration in AD. NRF2 has been reported to modulate microglia-induced inflammation and facilitate the transition from homeostatic microglia to a disease-associated microglia subset. Genetic and pharmacological activation of NRF2 has been demonstrated to improve cognitive function. Here, we review the current understanding of the involvement of NRF2 in AD and the critical role that NRF2 plays in microglia in the context of AD. Our aim is to highlight the potential of targeting NRF2 in the microglia as a promising therapeutic strategy for mitigating the progression of AD.

Alizarin attenuates oxidative stress-induced mitochondrial damage in vascular dementia rats by promoting TRPM2 ubiquitination and proteasomal degradation via Smurf2

BACKGROUND

Alizarin (AZ) is a natural anthraquinone with anti-inflammatory and moderate antioxidant properties.

PURPOSE

In this study, we characterized the role of AZ in a rat model of vascular dementia (VaD) and explored its underlying mechanisms.

METHODS

VaD was induced by bilateral common carotid artery occlusion.

RESULTS

We found that AZ attenuated oxidative stress and improved mitochondrial structure and function in VaD rats, which led to the improvement of their learning and memory function. Mechanistically, AZ reduced transient receptor potential melastatin 2 (TRPM2) expression and activation of the Janus-kinase and signal transducer activator of transcription (JAK-STAT) pathway in VaD rats. In particular, the reduction in the expression of TRPM2 channels was the key to the attenuation of the oxidative stress-induced mitochondrial damage, which may be achieved by increasing the expression of the E3 ubiquitin ligase, Smad-ubiquitination regulatory factor 2 (Smurf2); thereby increasing the ubiquitination and degradation levels of TRPM2.

CONCLUSION

Our results suggest that AZ is an effective candidate drug for ameliorating VaD and provide new insights into the current clinical treatment of VaD.

Azithromycin induces liver injury in mice by targeting the AMPK/Nrf2 pathway

BACKGROUND

Azithromycin is an antibacterial and anti-inflammatory drug widely used for the treatment of various diseases, including those caused by atypical pathogens, bacterial or viral infections, chronic sinusitis, and bronchial asthma, particularly in pediatric patients. However, concerns have emerged regarding its hepatotoxicity and its precise mechanism of action remains unclear.

OBJECTIVE

To investigate the molecular mechanisms responsible for azithromycin-induced acute liver injury to advance our understanding of the progression and pathogenesis of antibiotic-induced liver damage, and to improve prevention and treatment strategies.

MATERIALS AND METHODS

C57BL/6 mice, Nrf2-/- mice, and primary hepatocytes were used. Primary hepatocytes from mice were isolated using a two-step perfusion method and cultured in vitro via the 'sandwich' culture model.

RESULTS

The exposure to azithromycin resulted in increased apoptosis and reactive oxygen species (ROS) levels. In mouse models, intraperitoneal administration of azithromycin at varying concentrations and time points substantially induced hepatic disarray, swelling, and dysfunction. Azithromycin markedly upregulated the mRNA and protein levels of phosphorylated adenosine-activated protein kinase (AMPK) while downregulating nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), and NADPH: quinone oxidoreductase 1 (NQO-1). Moreover, HO-1 and NQO-1 protein levels remained largely unaffected in primary hepatocytes co-cultured with azithromycin in Nrf2-/- mice.

CONCLUSIONS

Our findings suggest that azithromycin-induced acute liver injury is mediated by suppression of Nrf2 activation and ROS production. This sheds light on the potential mechanisms involved in azithromycin-induced liver damage, underscoring the importance of exploring targeted interventions to mitigate the hepatotoxic effects.

Systematic Review and Phenome-Wide Scans of Genetic Associations with Vascular Cognitive Impairment

Vascular cognitive impairment (VCI) is a heterogenous form of cognitive impairment that results from cerebrovascular disease. It is a result of both genetic and non-genetic factors. Although much research has been conducted on the genetic contributors to other forms of cognitive impairment (e.g. Alzheimer's disease), knowledge is lacking on the genetic factors associated with VCI. A better understanding of the genetics of VCI will be critical for prevention and treatment. To begin to fill this gap, the genetic contributors are reviewed with VCI from the literature. Phenome-wide scans of the identified genes are conducted and genetic variants identified in the review in large-scale resources displaying genetic variant-trait association information. Gene set are also carried out enrichment analysis using the genes identified from the review. Thirty one articles are identified meeting the search criteria and filters, from which 107 unique protein-coding genes are noted related to VCI. The phenome-wide scans and gene set enrichment analysis identify pathways associated with a diverse set of biological systems. This results indicate that genes with evidence of involvement in VCI are involved in a diverse set of biological functions. This information can facilitate downstream research to better dissect possible shared biological mechanisms for future therapies.

Advancements in research on the effects of panax notoginseng saponin constituents in ameliorating learning and memory disorders

Learning and memory disorder is a cluster of symptoms caused by neuronal aging and other diseases of the central nervous system (CNS). Panax notoginseng saponins (PNS) are a series of saponins derived from the natural active ingredients of traditional Chinese medicine (TCM) that have neuroprotective effects on the central nervous system. In this paper, we review the ameliorative effects and mechanisms of Panax notoginseng saponin-like components on learning and memory disorders to provide valuable references and insights for the development of new drugs for the treatment of learning and memory disorders. Our summary results suggest that Panax ginseng saponins have significant effects on improving learning and memory disorders, and these effects and potential mechanisms are mediated by their anti-inflammatory, anti-apoptotic, antioxidant, β-amyloid lowering, mitochondrial homeostasis in vivo, neuronal structure and function improving, neurogenesis promoting, neurotransmitter release regulating, and probiotic homeostasis in vivo activities. These findings suggest the potential of Panax notoginseng saponin-like constituents as drug candidates for improving learning and memory disorders.

Nrf2 Signaling Pathway: a Potential Therapeutic Target in Combating Oxidative Stress and Neurotoxicity in Chemotherapy-Induced Cognitive Impairment

Chemotherapy-induced cognitive impairment (CICI) is one of the major adverse effects of antineoplastic drugs, which decrease the quality of life in cancer survivors. Extensive experimental and clinical research suggests that chemotherapeutic drugs generate an enormous amount of reactive oxygen species (ROS), contributing to oxidative stress, neuroinflammation, blood-brain barrier (BBB) disruption, and neuronal death, eventually leading to CICI. Despite the progress in exploring different pathological mechanisms of CICI, effective treatment to prevent CICI progression has not been developed yet. Nrf2 is the principal transcription factor that regulates cellular redox balance and inflammation-related gene expression. Emerging evidence suggests that upregulation of Nrf2 and its target genes could suppress oxidative stress, and neuroinflammation, restore BBB integrity, and increase neurogenesis. This review discusses the role of Nrf2 in CICI, how it responds to oxidative stress, inflammation, neurotoxicity, and potential Nrf2 activators that could be used to enhance Nrf2 activation in CICI.

Ferulic Acid Activates SIRT1-Mediated Ferroptosis Signaling Pathway to Improve Cognition Dysfunction in Wilson's Disease

BACKGROUND

Wilson's disease (WD), an autosomal recessive genetic disease, is characterized by copper metabolism disorder. WD patients may have a series of cognitive deficits in terms of neurological symptoms. Ferroptosis (FPT), a type of programmed cell death, is involved in the pathological progression of various cognitive disorders, and silent information regulator 1 (SIRT1) is considered to be a key factor in FPT. Ferulic acid (FA) is a traditional Chinese medicine monomer, with a remarkable effect in the clinical treatment of cognitive impairment-related disease. However, its intrinsic effect on FPT is still unclear. This study aims to investigate the protective effect of FA on cognitive impairment in animal and cell models of WD, and whether the pharmacological mechanism is related to the SIRT1-mediated FPT signaling pathway.

METHODS

Copper-loaded WD rats and PC12 cells WD were used as models of cognitive dysfunction in vivo and in vitro, respectively. Morris Water Maze (MWM) was used to evaluate the spatial exploration and memory abilities of rats. HE staining was used to observe neuronal damage in the CA1 region of the rat hippocampus. Immunofluorescence (IF) was used to detect the expression of GPX4 protein. Transmission electron microscopy (TEM) was used to observe the ultrastructure of neurons. The levels of Fe2+, MDA, SOD, GSH, 4HNE, and ROS were detected. Western blot and qRT-PCR were used to detect the protein and mRNA levels of SIRT1, Nrf2, SCL7A11, and GPX4.

RESULTS

In the WD copper-loaded model rats, MWM, TEM, and IF results showed that FA could promote the repair of learning and memory function, improve the morphological damage to hippocampal neurons, and maintain mitochondria integrity. In the PC12 cell experiment, the MTT method showed that FA increased the viability of copper-overloaded cell models. Western blot and qRT-PCR results confirmed that FA significantly increased the expression of proteins and mRNA in SIRT1, Nrf2, SCL7A11, and GPX4. In addition, FA reversed the expression of oxidative stress-related indicators, including MDA, SOD, GSH, 4HNE, and ROS.

CONCLUSION

FA alleviates hippocampal neuronal injury by activating SIRT1-mediated FPT, providing a valuable candidate for traditional Chinese medicine monomer for the clinical therapeutics of WD cognitive impairment.

Effects of Ischemic Stroke on Interstitial Fluid Clearance in Mouse Brain: a Bead Study

The clearance of brain interstitial fluid (ISF) is important in maintaining brain homeostasis. ISF clearance impairment leads to toxic material accumulation in the brain, and ischemic stroke could impair ISF clearance. The present study investigates ISF clearance under normal and ischemic conditions. The carboxylate-modified FluoSpheres beads (0.04 μm in diameter) were injected into the striatum. Sham or transient middle cerebral artery occlusion surgeries were performed on the mice. The brain sections were immunostained with cell markers, and bead distribution at various time points was examined with a confocal microscope. Primary mouse neuronal cultures were incubated with the beads to explore in vitro endocytosis.  Two physiological routes for ISF clearance were identified. The main one was to the lateral ventricle (LV) through the cleft between the striatum and the corpus callosum (CC)/external capsule (EC), where some beads were captured by the ependymal macrophages and choroid plexus. An alternative and minor route was to the subarachnoid space through the CC/EC and the cortex, where some of the beads were endocytosed by neurons. After ischemic stroke, a significant decrease in the main route and an increase in the minor route were observed. Additionally, microglia/macrophages engulfed the beads in the infarction. In conclusion, we report that the physiological clearance of ISF and beads mainly passes through the cleft between the CC/EC and striatum into the LV, or alternatively through the cortex into the subarachnoid space. Stroke delays the main route but enhances the minor route, and microglia/macrophages engulf the beads in the infarction. Ischemic stroke impairs the clearance of brain interstitial fluid/beads. Under physiological conditions, the main route ( ① ) of interstitial fluid clearance is to the lateral ventricle, and the minor one ( ② ) is to the subarachnoid space. Ischemic stroke weakens the main route ( ① ), enhances the minor one ( ② ), and leads to microglial/macrophage phagocytosis within the infarction ( ③ ).

[Photobiomodulation Promotes Hippocampal Neurogenesis and Improves Cognitive Function and Anti-Inflammatory Injury in Rats With Chronic Cerebral Hypoperfusion]

Objective

To investigate the effect of photobiomodulation (PBM) on hippocampal neurogenesis, cognitive function, and inflammatory injury in rats with chronic cerebral hypoperfusion.

Methods

Bilateral ovariectomy (OVX) was performed on female Sprague-Dawley (SD) rats. One week later, the rats were randomly assigned to three groups, Sham surgery (or Sham) group, bilateral common carotid artery occlusion (BCCAO) group, and PBM intervention (or BCCAO+PBM) group. There were 8 rats in each group. In the BCCAO group, chronic cerebral hyporeperfusion was induced by permanent ligation of bilateral common carotid arteries and no PBM was given. Rats in the Sham group underwent the same surgical procedure except for the occlusion of the two carotids arteries and no PBM was given. In addition to the BCCAO surgery, rats in the BCCAO+PBM group received 808 nm laser therapy (5 min each time at a laser dose of 20 mW/cm 2) of the frontal cortex every other day for 1 month. Between 86 and 90 days after BCCAO, Morris water maze (MWM) was used to observe the spatial learning and memory function of the rats. The rats were sacrificed on day 90 and immunofluorescence staining and Western blot were performed thereafter. Immunofluorescence staining was used to determine the expression of 5-bromodeoxyuracil nucleoside (BrdU), a cell proliferation marker, glial fibrillary acidic protein (GFAP), an astrocyte marker, doublecortin (DCX), a specific marker of newborn neuron precursor cells, NeuN, a marker of mature neurons, and Iba1, a microglia marker, in the hippocampal dentate gyrus (DG) region. Western blot was performed to analyze the protein expressions of inflammasome components, NLRP3, ASC, cleaved caspase-1, and Iba1 in the hippocampus.

Results

In the latency trial of MWM test, BCCAO+PBM rats spent shorter periods of time finding the underwater platform than the BCCAO rats did. In the probe trial, after the platform that was original placed in a quadrant was removed, the BCCAO+PBM rats spent longer periods of time exploring the quadrant than the BCCAO animals did ( P<0.05). Compared with BCCAO rats, BCCAO+PBM rats showed significant decrease in the immunofluorescence intensities of GFAP and Iba1 ( P<0.01). PBM intervention significantly increased the number of BrdU-positive cells in the hippocampal DG region compared with those of Sham and BCCAO groups ( P<0.05). Furthermore, the number of NeuN positive cells showed no significant difference among the three groups, while in BCCAO+PBM group, the number of DCX-positive cells was significantly increased ( P<0.001) and the number of DCX +/NeuN + co-located cells was significantly increased compared to that of the BCCAO group ( P<0.001). Compared with those of the BCCAO group, Western blot results showed that the protein expression levels of Iba1, NLRP3, and cleaved caspase-1 in the BCCAO+PBM group were significantly decreased ( P<0.05), while the ASC protein expression level showed no significant difference.

Conclusion

PBM can effectively improve the spatial learning and memory function in rats with chronic cerebral hypoperfusion, inhibit the activation of glial cells, reduce inflammatory damage mediated by NLRP3 inflammasome, and promote the regeneration of endogenous neural stem cells in the hippocampal DG region of rats.

Correlations among peripheral blood markers, white matter hyperintensity, and cognitive function in patients with non-disabling ischemic cerebrovascular events

BACKGROUND

Both inflammation and cerebral white matter injury are closely associated with vascular cognitive impairment (VCI). The aim of this study was to analyze the correlation between peripheral serological markers, white matter injury, and cognitive function in patients with non-disabling ischemic cerebrovascular events (NICE); to identify potential biological markers for the diagnosis and prediction of VCI; and to provide a basis for the early diagnosis and intervention of VCI.

METHODS

We collected clinical data, along with demographic and medical history data, from 151 NICE patients. Fasting venous blood samples were collected. Based on the Montreal Cognitive Assessment (MoCA) after admission, we divided the patients into normal cognitive function (NCF) and VCI groups, and then classified them into mild white matter hyperintensity (mWMH) and severe white matter hyperintensity (sWMH) based on Fazekas scores. The differences in serological marker levels were compared between the cognitive function groups and the white matter hyperintensity groups. Binary logistic regression models and receiver operating characteristic curves were used to analyze the diagnostic predictive value of serological markers for VCI in patients with NICE and in the white matter hyperintensity subgroups.

RESULTS

Among 151 patients with NICE, 95 were male and 56 were female. Lymphocyte count (OR = 0.405, p = 0.010, 95% CI [0.201, 0.806]), red blood cell count (OR = 0.433, p = 0.010, 95% CI [0.228, 0.821]), and hemoglobin level (OR = 0.979, p = 0.046, 95% CI [0.958, 0.999]) were protective factors for cognitive function in patients with NICE. The sWMH group had a higher age, granulocyte/lymphoid ratio (NLR), and neutrophil percentage but a lower MoCA score, hemoglobin level, and lymphocyte count than the mWMH group. In the mWMH group, lymphocyte count (AUC = 0.713, p = 0.003, 95% CI [0.593, 0.833]) had an acceptable predictive value for the diagnosis of VCI, whereas white blood cell count (AUC = 0.672, p = 0.011, 95% CI [0.545, 0.799]), red blood cell count (AUC = 0.665, p = 0.014, 95% CI [0.545, 0.784]), and hemoglobin level (AUC = 0.634, p = 0.047, 95% CI [0.502, 0.765]) had marginal predictive value for the diagnosis of VCI. In the sWMH group, no significant differences were found in serological markers between the NCF and VCI groups.

CONCLUSION

Lymphocyte count, red blood cell count, and hemoglobin level were independent protective factors for cognitive function in patients with NICE; they can be used as potential biological markers to distinguish VCI in patients with NICE and are applicable to subgroups of patients with mWMH.

RNA sequencing-based identification of the regulatory mechanism of microRNAs, transcription factors, and corresponding target genes involved in vascular dementia

Vascular dementia (VaD) is the second most common form of dementia with uncertain mechanisms and no effective treatments. microRNAs (miRNAs) and transcription factors (TFs) are considered regulatory factors of genes involved in many diseases. Therefore, this work investigated the aberrantly expressed miRNAs, TFs, corresponding target genes, and their co-regulatory networks in the cortex of rats with bilateral common carotid artery occlusion (2VO) to uncover the potential mechanism and biomarkers of VaD. Differentially expressed genes (DEGs), miRNAs (DEMs), and TFs (DETFs) were identified using RNA sequencing, and their interaction networks were constructed using Cytoscape. The results showed that rats with 2VO had declined cognitive abilities and neuronal loss in the cortex than sham rats. DEGs, DEMs, and DETFs were discriminated between rats with 2VO and sham rats in the cortex, as shown by the 13 aberrantly expressed miRNAs, 805 mRNAs, and 63 TFs. The miRNA-TF-target gene network was constructed, showing 523 nodes and 7237 edges. Five miRNAs (miR-5132-5p, miR-764-3p, miR-223-3p, miR-145-5p, and miR-122-5p), ten TFs (Mxi1, Nfatc4, Rxrg, Zfp523, Foxj2, Nkx6-1, Klf4, Klf5, Csrnp1, and Prdm6), and seven target genes (Serpine1, Nedd4l, Pxn, Col1a1, Plec, Trip12, and Tpm1) were chosen as the significant nodes to construct feed-forward loops (FFLs). Gene Ontology and pathway enrichment analysis revealed that these miRNA and TF-associated genes are mostly involved in the PI3K/Akt, neuroactive ligand–receptor interaction, calcium signaling, and Wnt signaling pathways, along with central locations around the cell membrane. They exert functions such as growth factor binding, integrin binding, and extracellular matrix structural constituent, with representative biological processes like vasculature development, cell–substrate adhesion, cellular response to growth factor stimulus, and synaptic transmission. Furthermore, the expression of three miRNAs (miR-145-5p, miR-122-5p, and miR-5132-5p), six TFs (Csrnp1, Klf4, Nfatc4, Rxrg, Foxj2, and Klf5), and five mRNAs (Serpine1, Plec, Nedd4l, Trip12, and Tpm1) were significantly changed in rats with VaD, in line with the outcome of RNA sequencing. In the potential FFL, miR-145-5p directly bound Csrnp1 and decreased its mRNA expression. These results might help the understanding of the underlying regulatory mechanisms of miRNA-TF-genes, providing potential therapeutic targets in VaD.

Naringenin Attenuates Cognitive Impairment in a Rat Model of Vascular Dementia by Inhibiting Hippocampal Oxidative Stress and Inflammatory Response and Promoting N-Methyl-D-Aspartate Receptor Signaling Pathway

Vascular dementia (VaD) is the second most common form of dementia globally, yet there are no efficient treatments. Naringenin, a natural flavonoid, exerts antioxidative, anti-inflammatory, and neuroprotective properties; however, its potential effect on VaD remain unclear. Herein, the purpose of present study was to elucidate whether naringenin attenuates cognitive dysfunction in VaD via inhibiting hippocampal oxidative stress and inflammatory response, and promoting N-methyl-D-aspartate receptors (NMDARs) signaling pathway. A rat model of VaD was established by permanent bilateral common carotid artery occlusion [2-vessel occlusion (2VO)]. Behavioral performance analyses results revealed that administration of naringenin improves cognitive impairment in rats with VaD according to the new object recognition test and the Morris water maze test. In addition, naringenin attenuated hippocampal oxidative stress by reducing reactive oxygen species generation, decreasing malondialdehyde content and recombinant reactive oxygen species modulator 1 (Romo-1) expression, and increasing superoxide dismutase and glutathione peroxidase activities in the hippocampus of VaD rats. Moreover, naringenin decreased the proinflammatory cytokines (IL-1β, IL-6, and TNF-α) levels and increased the anti-inflammatory cytokines (IL-10 and IL-4) levels in the hippocampus of 2VO surgery-treated rats, attenuating hippocampal inflammatory response during VaD. Furthermore, naringenin promoted synaptophysin (SYP), postsynaptic density protein 95 (PSD95), N-methyl-Daspartic acid receptor 1 (NR1) and N-methyl-D-aspartate receptor subunit 2B (NR2B) expressions levels in hippocampus of VaD rats. Collectively, these findings indicated that naringenin mitigates cognitive impairment in VaD rats partly via inhibiting hippocampal oxidative stress and inflammatory response and restoring NMDARs signaling pathway.

MicroRNA-Based Diagnosis and Therapeutics for Vascular Cognitive Impairment and Dementia

Vascular cognitive impairment and dementia (VCID) is a neurodegenerative disease that is recognized as the second leading cause of dementia after Alzheimer's disease (AD). The underlying pathological mechanism of VCID include crebromicrovascular dysfunction, blood-brain barrier (BBB) disruption, neuroinflammation, capillary rarefaction, and microhemorrhages, etc. Despite the high incidence of VCID, no effective therapies are currently available for preventing or delaying its progression. Recently, pathophysiological microRNAs (miRNAs) in VCID have shown promise as novel diagnostic biomarkers and therapeutic targets. Studies have revealed that miRNAs can regulate the function of the BBB, affect apoptosis and oxidative stress (OS) in the central nervous system, and modulate neuroinflammation and neurodifferentiation. Thus, this review summarizes recent findings on VCID and miRNAs, focusing on their correlation and contribution to the development of VCID pathology.