Brain Of Mouse Model Research Articles

Shisandra Decoction Alleviates Parkinson's Disease Symptoms in a Mouse Model Through PI3K/AKT/mTOR Signalling Pathway.

The present study aimed to characterize neuroprotective effects of Schisandra Decoction (Sch D) treatment in a mouse model of Parkinson's disease (PD), and to explore underlying mechanisms focused on the mammalian target of rapamycin (mTOR) signaling pathway. 50 male C57 BL/6 mice were randomly assigned to either control (n = 10) or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model (n = 40) groups. PD mice were further divided into four groups of ten mice each: MPTP group, LY294002 group, Sch D group, and LY2940002 + Sch D group. Mice from each group were assessed in pole climbing, rotary rod and open field tests. Brain Tyrosine hydroxylase (TH) protein was observed using immunohistochemistry. mRNA levels of PTEN, PI3K and LC3 in brain tissue were measured using RT-PCR. Protein levels of PTEN, PI3K, Akt, p-Akt, mTOR, p-mTOR, p70s6K, p62, LC3II / I, α-synuclein (α-syn), TH in brain tissue were assessed by Western blotting (WB). In behavioral tests, PD mice treated with Sch D showed reduced pole climbing time, longer rotarod duration, and greater distance traveled. In terms of neuroprotection, PD mice in the Sch D group exhibited higher levels of TH protein and enhanced α-syn clearance. Regarding autophagy, compared to the control group, mice in the MPTP group had elevated PTEN protein expression, which inhibited PI3K, p-AKT/AKT, and p-mTOR/mTOR protein levels, decreased LC3II/I protein expression, and increased P62 protein expression. Treatment with Sch D reversed these effects. Sch D reduces α-syn aggregation in the brains of MPTP-induced PD model mice, exerts neuroprotective effects, and improves motor function. Additionally, Sch D inhibits autophagy through the PI3K/AKT/mTOR pathway. The neuroprotective effect of Sch D may involve the suppression of abnormal autophagy and its antioxidant properties, which indirectly reduces α-syn accumulation. Future studies should assess the impact of Sch D on oxidative stress markers to evaluate its antioxidant effects.

Targeting ceramide-induced microglial pyroptosis: Icariin is a promising therapeutic therapy for Alzheimer's disease

Alzheimer’s disease (AD), a progressive dementia, is one of the most common neurodegenerative diseases. Clinical trial results of amyloid-β (Aβ) and tau regulators based on the pretext of straightforward amyloid and tau immunotherapy were disappointing. There are currently no effective strategies for slowing the progression of AD. Herein, we spotlight the dysregulation of lipid metabolism, particularly the elevation of ceramides (Cers), as a critical yet underexplored facet of AD pathogenesis. Our study delineates the role of Cers in promoting microglial pyroptosis, a form of programmed cell death distinct from apoptosis and necroptosis, characterized by cellular swelling, and membrane rupture mediated by the NLRP3 inflammasome pathway. Utilizing both in vivo experiments with APP/PS1 transgenic mice and in vitro assays with BV-2 microglial cells, we investigate the activation of microglial pyroptosis by Cers and its inhibition by Icariin (ICA), a flavonoid with known antioxidant and anti-inflammatory properties. Our findings reveal a significant increase in Cers levels and pyroptosis markers (NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain, caspase-1, gasdermin D, and interleukin-18) in the brains of AD model mice, indicating a direct involvement of Cers in AD pathology through the induction of microglial pyroptosis. Conversely, ICA treatment effectively reduces these pyroptotic markers and Cer levels, thereby attenuating microglial pyroptosis and suggesting a novel therapeutic mechanism of action against AD. This study not only advances our understanding of the pathogenic role of Cers in AD but also introduces ICA as a promising candidate for AD therapy, capable of mitigating neuroinflammation and pyroptosis through the COX2-NLRP3 inflammasome-GSDMD axis. Our results pave the way for further exploration of Cer metabolism disorders in neurodegenerative diseases and highlight the therapeutic potential of targeting microglial pyroptosis in AD.

Distinct functional diversity of branched oligosaccharides as chaperones and inhibitory-binding partners of amyloid beta-protein and its aggregates

Aggregation and deposition of amyloid beta-protein 1–42 (Aβ42) in the brain, primarily owing to hydrophobic interactions between Aβ42 chains, is a common pathology in all forms of Alzheimer's disease (AD). Hydrophilic oligosaccharides are widely present in the extracellular matrix and on the cytoplasmic membrane. To determine if oligosaccharides bind to Aβ42 or its aggregates and consequently affect their aggregation and cellular function, this study examined the interaction of typical functional oligosaccharides with Aβ42 or its aggregates. Isomaltooligosaccharides (IMOs), particularly isomaltotriose, panose, and isomaltotetraose, functioned as molecular chaperones for Aβ42 by binding directly to Aβ42, preserving Aβ42's active conformation and cytotrophic activity. Oral IMOs reduced total plasma Aβ level and indirectly caused a slight reduction in the load of Aβ42 spots/plaques in the brain of AD model mice (male). Another branched oligosaccharide, bianntennary core pentasaccharide (BCP), had a relatively high binding specificity for Aβ42 oligomers (Aβ42O) and acted as an antagonistic binding partner for Aβ42O. Free BCP effectively blocked/prevented further assembly of Aβ42O and their toxicity to neural and vascular endothelial cell lines. Since BCP is also a signaling component of membrane targets (glycolipids, glycoproteins or receptors), it seemed that BCP had two opposing effects on the binding of Aβ42O to target cells. This study's findings suggest that these branched oligosaccharides may be potential candidates for blocking or preventing Aβ42 aggregation and Aβ42O cytotoxicity/neurotoxicity, respectively, and that IMO-like or free BCP-like oligosaccharide deficiencies in the brain may be one of the underlying mechanisms for Aβ42 aggregation and Aβ42O cytotoxicity.

(Invited) Development of Leuco Ethyl Violet as Self-Activating Prodrug Photooxygenation Catalyst of Amyloid-β

Abnormal aggregation of amyloid-β (Aβ) and tau protein (tau), called amyloid, is characteristic of Alzheimer's disease (AD). Reducing amyloid levels in AD patients is expected to be an effective approach to AD treatment. To inhibit the hydrophobic interaction of amyloid, which is the cause of toxic aggregates, we planed to generate singlet oxygen by activating oxygen in vivo through photocatalysis, thereby introducing oxygen atoms to amyloid protein and inhibiting aggregation. In accordance with this concept, we are developing photooxygenation catalysts with a switch function that generates singlet oxygen only in the presence of amyloids. We have succeeded in reducing amyloid in AD model mouse brain non-invasively with this photo-oxygenation catalyst. However, moderate catalytic activity and the side effect of scalp damage have been problematic. This time, we identified leucoethyl violet (LEV) as a highly active, amyloid-selective, blood-brain barrier (BBB)-permeable photooxygenation catalyst. LEV is a self-activating procatalyst by external redox stimuli. Autoxidation of LEV by a hydrogen atom transfer process under light irradiation produced active catalyst species Ethyl Violet (EV) only in the presence of amyloids. LEV showed higher catalytic activity than the previously developed photooxygenation catalyst and realized oxygenation of human Aβ and tau. Taking advantage of LEV's high activity and amyloid selectivity, improved BBB permeability, and low cytotoxicity, photooxygenation of Aβ was achieved in an AD model without scalp injury. Figure 1

1H-NMR-based metabolomics reveals metabolic alterations in early development of a mouse model of Angelman syndrome

BackgroundAngelman syndrome (AS) is a rare neurodevelopmental genetic disorder caused by the loss of function of the ubiquitin ligase E3A (UBE3A) gene, affecting approximately 1:15,000 live births. We have recently shown that mitochondrial function in AS is altered during mid to late embryonic brain development leading to increased oxidative stress and enhanced apoptosis of neural precursor cells. However, the overall alterations of metabolic processes are still unknown. Hence, as a follow-up, we aim to investigate the metabolic profiles of wild-type (WT) and AS littermates and to identify which metabolic processes are aberrant in the brain of AS model mice during embryonic development.MethodsWe collected brain tissue samples from mice embryos at E16.5 and performed metabolomic analyses using proton nuclear magnetic resonance (1H-NMR) spectroscopy. Multivariate and Univariate analyses were performed to determine the significantly altered metabolites in AS mice. Pathways associated with the altered metabolites were identified using metabolite set enrichment analysis.ResultsOur analysis showed that overall, the metabolomic fingerprint of AS embryonic brains differed from those of their WT littermates. Moreover, we revealed a significant elevation of distinct metabolites, such as acetate, lactate, and succinate in the AS samples compared to the WT samples. The elevated metabolites were significantly associated with the pyruvate metabolism and glycolytic pathways.LimitationsOnly 14 metabolites were successfully identified and investigated in the present study. The effect of unidentified metabolites and their unresolved peaks was not determined. Additionally, we conducted the metabolomic study on whole brain tissue samples. Employing high-resolution NMR studies on different brain regions could further expand our knowledge regarding metabolic alterations in the AS brain. Furthermore, increasing the sample size could reveal the involvement of more significantly altered metabolites in the pathophysiology of the AS brain.ConclusionsUbe3a loss of function alters bioenergy-related metabolism in the AS brain during embryonic development. Furthermore, these neurochemical changes could be linked to the mitochondrial reactive oxygen species and oxidative stress that occurs during the AS embryonic development.

Targeting zincosomes to unveil lysosomal zinc ion dynamics and their role in exacerbating Alzheimer's pathology

Maintaining lysosomal zinc (Zn2+) homeostasis is crucial for cellular functionality, with its dysregulation implicated in the progression of neurodegenerative disorders, notably Alzheimer's disease (AD). The paucity of effective tools for precise lysosomal Zn2+ visualization has been a significant barrier to elucidating its role in AD. In response, a highly sensitive and selective novel fluorescent probe based on a salicylaldehyde Schiff base derivative, SSb, was developed to visualize Zn2+ dynamics. Our findings unveil a previously uncharacterized Zn2+ transport mechanism via zincosomes, highlighting their engulfment by mitochondria during autophagy, facilitated by SSb. Significantly, Zn2+ levels were found to be elevated in the brains of AD model mice, associated with amyloid-β (Aβ) deposits. Additionally, our study indicates an abnormal activation of autophagy in AD models, suggesting that Zn2+ increment may exacerbate AD pathology by fostering Aβ deposition and toxicity. This investigation provides valuable insights into Zn2+ homeostasis and its impact on AD, laying the groundwork for novel diagnostic and therapeutic avenues in combating AD, further reflecting the interdisciplinary nature of chemical engineering and biomedical research.

A classic prescription alleviates inflammation in CUMS model mice via modulating MYDGF/MAP4K4/NF-κB signaling pathway, verified through UPLC-HRMS and proteomics analysis

BackgroundXiaoyaosan (XYS), a renowned classical traditional Chinese medicinal formula utilized in addressing major depressive disorder (MDD), has garnered significant acclaim for its remarkable efficacy in clinical application. The onset of major depressive disorder (MDD) often correlates with chronic unpredictable mild stress (CUMS), a pivotal instigating factor in its development.Aim of the study: This study aims to clarify the potential anti-inflammatory mechanisms of XYS in treating CUMS model mice. Materials and methodsUtilizing cutting-edge ultra high-performance liquid chromatography - high-resolution mass spectrometry (UPLC-HRMS), the active constituents of XYS were discerned, while employing proteomics analysis to delve into the potential mechanisms of its efficacy. Molecular docking studies, alongside subsequent in vivo experiments utilizing CUMS model mice, were conducted to corroborate the findings derived from the proteomics analysis. ResultsIn vivo experiments demonstrated that XYS not only markedly ameliorated behavioral markers but also attenuated serum inflammatory markers and suppressed IL-6 and TNF-α expression within the brains of CUMS model mice. Proteomics analysis suggested that the pivotal anti-inflammatory mechanism of XYS against CUMS-induced damage might involve modulation of the MAPK signaling pathway. Utilizing UPLC-HRMS, the active constituents of XYS were successfully identified, while molecular docking investigations explored interactions between XYS and MYDGF, PKC, MAP4K4, P-p65, p65, P-IKBα, and IKBα. The findings revealed XYS's regulatory influence on the MYDGF/MAP4K4/NF-κB signaling cascade. ConclusionsThis study is the first to our knowledge to demonstrate that XYS can alleviate inflammation in CUMS model mice by modulating the MYDGF/MAP4K4/NF-κB signaling pathway.

Development of Triphenylmethane Dyes for In Vivo Fluorescence Imaging of Aβ Oligomers.

Detection of amyloid β (Aβ) oligomers, regarded as the most toxic aggregated forms of Aβ, can contribute to the diagnosis and treatment of Alzheimer's disease (AD). Thus, the development of imaging probes for in vivo visualization of Aβ oligomers is crucial. However, the structural uncertainty regarding Aβ oligomers makes it difficult to design imaging probes with high sensitivity to Aβ oligomers against highly aggregated Aβ fibrils. In this study, we developed Aβ oligomer-selective fluorescent probes based on triphenylmethane dyes through screening of commercially available compounds followed by structure-activity relationship (SAR) studies on cyclic or acyclic 4-dialkylamino groups. We synthesized 11 triarylmethane-based Aβ oligomer probe (TAMAOP) derivatives. In vitro evaluation of fluorescence properties, TAMAOP-9, which had bulky 4-diisobutylamino groups introduced into three benzenes of a twisted triphenylmethane backbone, showed marked fluorescence enhancement in the presence of Aβ oligomers and demonstrated high selectivity for Aβ oligomers against Aβ fibrils. In docking studies using the Aβ trimer model, TAMAOP-9 bound to the hydrophobic surface and interacted with the side chain of Phe20. In vitro section staining revealed that TAMAOP-9 could visualize Aβ oligomers in the brains of AD model mice. An in vivo fluorescence imaging study using TAMAOP-9 showed significantly higher fluorescence signals from the brains of AD model mice than those of age-matched wild-type mice, confirmed by ex vivo section observation. These results suggest that TAMAOP-9 is a promising Aβ oligomer-targeting fluorescent probe applicable to in vivo imaging.

The Effects of Ketogenic Diet on Brain Gene Expressions in Type 2 Diabetes Background

Type 2 diabetes mellitus (T2DM) is a major risk factor of a number of neurodegenerative diseases (NDDs). Ketogenic diet (KD) has significant beneficial effects on glycemic control and may act effectively against NDDs, but the mechanism remains unclear. In this study, we aimed to investigate the potential effects of KD on gene expressions in the brains of T2DM model mice. Male db/db mice at the age of 9 weeks were fed with KD or normal diet to the age of 6 months, and the whole brains were subjected to mRNA-seq analysis for differentially expressed genes. KD significantly lowered fasting glucose and body weights in db/db mice (P < 0.05), and the expression of 189 genes in the brain were significantly changed (P < 0.05, |log2| > 1). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the differentially expressed genes upon KD are involved in inflammatory responses and the functions of biosynthesis. In inflammatory responses, NF-κB signaling pathway, viral protein interaction with cytokine and cytokine receptor, and cytokine-cytokine receptor interaction pathways were enriched, and in biosynthesis pathways, genes functioning in lipid and amino acid metabolism, protein synthesis, and energy metabolism were enriched. Moreover, consistent with the gene set enrichment analysis results, proteasomal activity measured biochemically were enhanced in KD-fed T2DM mice. These data may facilitate the understanding of how KD can be protective to the brain in T2DM background. KD could be a new strategy for the prevention of NDDs in T2DM patients.

Neuroinflammation in Cryptococcal Post-infectious Inflammatory Response Syndrome (PIIRS) is reduced by Ruxolitinib, a Janus Kinase (JAK) inhibitor.

Abstract Recently, a PIIRS was described in non-HIV infected cryptococcal meningoencephalitis (CM) as a significant cause of neuropathology and mortality. Inflammatory syndromes are particularly severe in neurological infections due to the skull's rigid structure. In the present study, transcriptional profiling of RNA from brains of PIIRS model mice at peak inflammation identified a predominance of STAT1/STAT3-associated downstream genes. Since JAK is known to activate both pathways, we hypothesized that the JAK/STAT inhibitor ruxolitinib could reduce neuro-damaging inflammation from CM. Treatment with ruxolitinib reduced intrathecal STAT1/STAT3-associated gene expression as well as CD44hiCD62loCD4+ effector CD4+ T-cells and MHC II+ inflammatory myeloid cells with improved neuropathology and weight. Based on these data, the first human treatment of PIIRS with ruxolitinib was initiated in 5 patients with residual inflammation despite corticosteroids (CS). Ruxolitinib reduced cerebrospinal fluid (CSF) activated HLA-DR+ CD4+ and CD8+ cells, NK cells, and inflammatory monocytes as well as soluble markers sIL-2R, and IL-10 with a trend in IL-6 on a constant dose of CS. MRI brain imaging also demonstrated significant improvements and therapy was well tolerated. Together, these findings demonstrate a role for the JAK/STAT pathway in PIIRS and support ruxolitinib as a potential adjunctive therapy for further randomized clinical trials of PIIRS as a steroid-sparing therapeutic.

Identification of senescent, TREM2-expressing microglia in aging and Alzheimer's disease model mouse brain.

Alzheimer's disease (AD) and dementia in general are age-related diseases with multiple contributing factors, including brain inflammation. Microglia, and specifically those expressing the AD risk gene TREM2, are considered important players in AD, but their exact contribution to pathology remains unclear. In this study, using high-throughput mass cytometry in the 5×FAD mouse model of amyloidosis, we identified senescent microglia that express high levels of TREM2 but also exhibit a distinct signature from TREM2-dependent disease-associated microglia (DAM). This senescent microglial protein signature was found in various mouse models that show cognitive decline, including aging, amyloidosis and tauopathy. TREM2-null mice had fewer microglia with a senescent signature. Treating 5×FAD mice with the senolytic BCL2 family inhibitor ABT-737 reduced senescent microglia, but not the DAM population, and this was accompanied by improved cognition and reduced brain inflammation. Our results suggest a dual and opposite involvement of TREM2 in microglial states, which must be considered when contemplating TREM2 as a therapeutic target in AD.

Cytisine–N-methylene-(5,7,4’-trihydroxy)- isoflavone ameliorates ischemic stroke-induced brain injury in mouse by regulating the oxidative stress and BDNF-Trkb/Akt pathway

BackgroundA novel compound Cytisine–N-methylene-(5,7,4′-trihydroxy)- isoflavone (LY01) found in the Sophora alopecuroides L is a neuroprotective agent. However, the effect and potential mechanism of LY01 treatment for ischemic stroke (IS) have not been fully elucidated. Aim of the studyThe aim of this study is to demonstrate whether LY01 can rescue ischemic stroke-induced brain injury and oxygen–glucose deprivation/reperfusion (OGD/R). ResultsOur results show that intragastric administration of LY01 improves ischemic stroke behaviors in mice, as demonstrated by neurological score, infarct volume, cerebral water content, rotarod test for activity. Compared with the model group, the ginkgo biloba extract (EGb) and LY01 reversed the neurological score, infarct volume, cerebral water content, rotarod test in model mice. Further analysis showed that the LY01 rescued oxidative stress in the model mice, which was reflected in the increased levels of catalase, superoxide dismutase, total antioxidant capacity and decreased levels of malondialdehyde in the serum of the model mice. Moreover, the expression of the brain-derived neurotrophic factor brain-derived neurotrophic factor (BDNF), phosphorylated protein kinase B (p-Akt), Bax, Bcl-2, (p)-tropomysin related kinase B (p-Trkb) was restored and the expression of Bax, glial fibrillary acidic protein (GFAP) in the brains of the model mice was inhibited through LY01 treatment. In the polymerase chain reaction (PCR) data, after giving LY01, the expression in the brains of model mice was that, IL-10 increased and IL-1β, Bax, Bcl-2 decreased. Furthermore, the results indicated that LY01 improved cell viability, reactive oxygen species content, and mitochondrial membrane potential dissipation induced by OGD/R in primary culture of rat cortical neurons. Bax and caspase-3 activity was upregulated compared to the before after treatment with LY01. ConclusionsOur study suggests that LY01 reversed ischemic stroke by reducing oxidative stress and activating the BDNF-TrkB/Akt pathway and exerted a neuroprotective action against OGD/R injury via attenuation, a novel approach was suggested to treat ischemic stroke. Our observations justify the traditional use of LY01 for a treatment of IS in nervous system.

Transmissibility of phosphorylated -synuclein in the brain of Parkinsons Disease model mice

Parkinsons disease (PD) is a chronic neurodegenerative disease. The pathogenesis of PD is the misfolding and accumulation of the alpha-synuclein protein leading to degeneration and death of dopaminergic neurons in the Substantia nigra. This study focuses on the transmissibility of phosphorylated -synuclein in the brain of PD model mice. In this study, DAT-IRES-Cre+/-/LSL-SNCA-GFP+/- mice was used as a model, and experimental techniques including frozen section of mouse brain, immunohistochemical staining, and confocal microscopy were used to investigate the transmission of -synuclein as well as Lewy bodies, which are abnormal aggregates of -synuclein, in the mouse brain. We conclude that phosphorylated -synuclein (pSyn) can propagate from the dorsal striatum to the Substantia Nigra Pars Compacta (SNc) through the dopaminergic pathway, resulting in the formation of Lewy bodies in dopaminergic neurons in the SNc, causing neuronal death and thus leading to the pathogenesis of Parkinsons disease.

A Small-Molecule Ratiometric Photoacoustic Probe for the High-Spatiotemporal-Resolution Imaging of Copper(II) Dynamics in the Mouse Brain.

Copper dysmetabolism is associated with various neurodegenerative disorders, making high-spatiotemporal-resolution imaging of Cu2+ in the brain essential for understanding the underlying pathophysiological processes. Nevertheless, the current probes encounter obstacles in crossing the blood-brain barrier (BBB) and providing high-spatial-resolution in deep tissues. Herein, we present a photoacoustic probe capable of imaging Cu2+ dynamics in the mouse brain with high-spatiotemporal-resolution. The probe demonstrates selective ratiometric and reversible responses to Cu2+ , while also efficiently crossing the BBB. Using the probe as the imaging agent, we successfully visualized Cu2+ in the brain of Parkinson's disease (PD) model mouse with a remarkable micron-level resolution. The imaging results revealed a significant increase in Cu2+ levels in the cerebral cortex as PD progresses, highlighting the close association between Cu2+ alternations in the region and the disease. We also demonstrated that the probe can be used to monitor changes in Cu2+ distribution in the PD model mouse brain during L-dopa intervention. Mechanism studies suggest that the copper dyshomeostasis in the PD mouse brain was dominated by the expression levels of divalent metal transporter 1. The application of our probe in imaging Cu2+ dynamics in the mouse brain offers valuable insights into the copper-related molecular mechanisms underlying neurodegenerative diseases.

A Small‐Molecule Ratiometric Photoacoustic Probe for the High‐Spatiotemporal‐Resolution Imaging of Copper(II) Dynamics in the Mouse Brain

AbstractCopper dysmetabolism is associated with various neurodegenerative disorders, making high‐spatiotemporal‐resolution imaging of Cu2+ in the brain essential for understanding the underlying pathophysiological processes. Nevertheless, the current probes encounter obstacles in crossing the blood–brain barrier (BBB) and providing high‐spatial‐resolution in deep tissues. Herein, we present a photoacoustic probe capable of imaging Cu2+ dynamics in the mouse brain with high‐spatiotemporal‐resolution. The probe demonstrates selective ratiometric and reversible responses to Cu2+, while also efficiently crossing the BBB. Using the probe as the imaging agent, we successfully visualized Cu2+ in the brain of Parkinson's disease (PD) model mouse with a remarkable micron‐level resolution. The imaging results revealed a significant increase in Cu2+ levels in the cerebral cortex as PD progresses, highlighting the close association between Cu2+ alternations in the region and the disease. We also demonstrated that the probe can be used to monitor changes in Cu2+ distribution in the PD model mouse brain during L‐dopa intervention. Mechanism studies suggest that the copper dyshomeostasis in the PD mouse brain was dominated by the expression levels of divalent metal transporter 1. The application of our probe in imaging Cu2+ dynamics in the mouse brain offers valuable insights into the copper‐related molecular mechanisms underlying neurodegenerative diseases.

Golgi-targeting viscosity probe for the diagnosis of Alzheimer’s disease

Early diagnosis and intervention of Alzheimer’s disease (AD) are particularly important to delay the pathological progression. Although fluorescent probes have been widely employed for investigating and diagnosing AD, their biological applications are significantly restricted due to the low penetration ability of the blood–brain barrier (BBB) in vivo. In this study, we reported the first Golgi-targeted two-photon (TP) fluorescent probe, DCM-DH, for detecting viscosity in the Golgi apparatus. The probe was rationally designed to exhibit superior analytical performance including high sensitivity, specific Golgi-targeting, efficient BBB penetration ability, and deep tissue penetration (247 μm) in the brains of AD model mice. Using the probe, we demonstrated that the fluorescence intensity in the human liver cancer cell (HepG2 cells) was higher than that of human normal liver cell (LO2 cells), and the brain viscosity of AD model mice increased significantly. We anticipate that this competent tool could be easily extended to other AD biomarkers for fundamental research on this detrimental disease.

A novel NIR fluorescent probe for copper(ii) imaging in Parkinson's disease mouse brain.

Abnormal copper ion (Cu2+) levels are considered to be one of the pathological factors of Parkinson's disease (PD), but the internal relationship between Cu2+ and PD progression remains elusive. Visualizing Cu2+ in the brain will be pivotal for comprehending the underlying pathophysiological processes of PD. In this work, a near-infrared (NIR) fluorescent probe, DDAO-Cu, capable of detecting Cu2+ with exceptional sensitivity (about 1.8 nM of detection limit) and selectivity, rapid response (<3 min), and deep tissue penetration, was designed for quantification and visualization of the Cu2+ level. It could detect not only Cu2+ in cells but also the changes in the Cu2+ level in the rotenone-induced cell and zebrafish PD models. Moreover, DDAO-Cu can cross the blood-brain barrier to image Cu2+ in the brain of PD model mice. The imaging result showed a significant increase in Cu2+ levels in brain regions of PD model mice, including the cerebral cortex, hippocampus, and striatum. Meanwhile, Cu2+ levels in the substantia nigra region were significantly reduced in PD model mice. It revealed the nuanced relationship of Cu2+ levels in different brain regions in the disease and indicated the pathological complexity of PD. Overall, DDAO-Cu represents a novel and practical tool for investigating Cu2+-related physiological and pathological processes underlying Parkinson's disease.

Microglial circ-UBE2K exacerbates depression by regulating parental gene UBE2K via targeting HNRNPU.

Background: Knowledge about the pathogenesis of depression and treatments for this disease are lacking. Epigenetics-related circRNAs are likely involved in the mechanism of depression and have great potential as treatment targets, but their mechanism of action is still unclear. Methods: Circular RNA UBE2K (circ-UBE2K) was screened from peripheral blood of patients with major depressive disorder (MDD) and brain of depression model mice through high-throughput sequencing. Microinjection of circ-UBE2K overexpression lentivirus and adeno-associated virus for interfering with microglial circ-UBE2K into the mouse hippocampus was used to observe the role of circ-UBE2K in MDD. Sucrose preference, forced swim, tail suspension and open filed tests were performed to evaluate the depressive-like behaviors of mice. Immunofluorescence and Western blotting analysis of the effects of circ-UBE2K on microglial activation and immune inflammation. Pull-down-mass spectrometry assay, RNA immunoprecipitation (RIP) test and fluorescence in situ hybridization (FISH) were used to identify downstream targets of circ-UBE2K/ HNRNPU (heterogeneous nuclear ribonucleoprotein U) axis. Results: In this study, through high-throughput sequencing and large-scale screening, we found that circ-UBE2K levels were significantly elevated both in the peripheral blood of patients with MDD and in the brains of depression model mice. Functionally, circ-UBE2K-overexpressing mice exhibited worsened depression-like symptoms, elevated brain inflammatory factor levels, and abnormal microglial activation. Knocking down circ-UBE2K mitigated these changes. Mechanistically, we found that circ-UBE2K binds to heterogeneous nuclear ribonucleoprotein U (HNRNPU) to form a complex that upregulates the expression of the parental gene ubiquitin conjugating enzyme E2 K (UBE2K), leading to abnormal microglial activation and neuroinflammation and promoting the occurrence and development of depression. Conclusions: The findings of the present study revealed that the expression of circUBE2K, which combines with HNRNPU to form the circUBE2K/HNRNPU complex, is increased in microglia after external stress, thus regulating the expression of the parental gene UBE2K and mediating the abnormal activation of microglia to induce neuroinflammation, promoting the development of MDD. These results indicate that circ-UBE2K plays a newly discovered role in the pathogenesis of depression.

Berberine Mediates the Production of Butyrate to Ameliorate Cerebral Ischemia via the Gut Microbiota in Mice.

Ischemic stroke (IS) is a vascular disease group concomitant with high morbidity and mortality. Berberine is a bioactive substance and it has been known to improve stroke, but its mechanism is yet to be proven. Mice were fed with BBR for 14 days. Then, the mice were made into MCAO/R models. Neurological score, infarct volume, neuronal damage and markers associated with inflammation were detected. We tested the changes in intestinal flora in model mice after BBR administration using 16SrRNA sequencing. Chromatography-mass spectrometry was used to detect butyrate chemically. Tissue immunofluorescence was used to detect the changes in the microglia and astroglia in the mice brains. Our findings suggest that berberine improves stroke outcomes by modulating the gut microbiota. Specifically, after MCAO/R mice were given berberine, the beneficial bacteria producing butyric acid increased significantly, and the mice also had significantly higher levels of butyric acid. The administration of butyric acid and an inhibitor of butyric acid synthesis, heptanoyl-CoA, showed that butyric acid improved the stroke outcomes in the model mice. In addition, butyric acid could inhibit the activation of the microglia and astrocytes in the brains of model mice, thereby inhibiting the generation of pro-inflammatory factors IL-6, IL-1β and TNF-α as well as improving stroke outcomes. Our results suggest that berberine may improve stroke outcomes by modulating the gut flora to increase the abundance of butyric acid. These findings elucidate the mechanisms by which berberine improves stroke outcomes and provide some basis for clinical treatment.

Development of a brain-targeted nano drug delivery system to enhance the treatment of neurodegenerative effects of resveratrol

As the aging population continues to increase, aging-related inflammation, oxidative stress, and neurodegenerative diseases have become serious global health threats. Resveratrol, a star molecule in natural polyphenols, has been widely reported to have physiological activities such as anti-aging, anti-inflammatory, antioxidant, and neuroprotection. However, its poor water solubility, rapid metabolism, low bioavailability and poor targeting ability, which limits its application. Accordingly, a brain-targeted resveratrol liposome (ANG-RES-LIP) was developed to solve these issues. Experimental results showed that ANG-RES-LIP has a uniform size distribution, good biocompatibility, and a drug encapsulation rate of over 90%. Furthermore, in vitro cell experiments showed that the modification of the targeting ligand ANG significantly increased the capability of RES to cross the BBB and neuronal uptake. Compared with free RES, ANG-RES-LIP demonstrated stronger antioxidant activity and the ability to rescue oxidatively damaged cells from apoptosis. Additionally, ANG-RES-LIP showed the ability to repair damaged neuronal mitochondrial membrane potential. In vivo experiments further demonstrated that ANG-RES-LIP improved cognitive function by reducing oxidative stress and inflammation levels in the brains of aging model mice, repairing damaged neurons and glial cells, and increasing brain-derived neurotrophic factor. In summary, this study not only provides a new method for further development and application of resveratrol but also a promising strategy for preventing and treating age-related neurodegenerative diseases.