ABSTRACT Alzheimer's disease (AD) is a neurodegenerative disorder that currently lacks cures; thus, searching for new biomarkers and unraveling its underlying mechanisms are crucial for devising effective therapies. Here, we discovered that both mRNA and protein levels of CD31 (platelet endothelial cell adhesion molecule‐1, PECAM1), a transmembrane glycoprotein in immunoglobulin superfamily, were significantly higher in the brains of AD individuals and different AD transgenic mice, and the elevated CD31 was related to the recognized AD pathologies. Additional studies demonstrated that systemically knockdown of CD31 in 5xFAD mice significantly improved the cognitive functions with decreased AD hallmark pathologies, including β‐amyloid precipitation and tau hyperphosphorylation. Moreover, CD31 knockdown alleviated neuroinflammation, evidenced by the diminished microglial stimulation and suppressed expression of pro‐inflammatory cytokines. Transcriptomic analysis indicated considerable changes in the AD‐involved gene expression in 5xFAD mice, and CD31 knockdown rectified imbalanced gene expression. Mechanistically, we further revealed that CD31 knockdown suppressed the expression of STAT1 and IRF1 by reducing histone lactylation at H3K14 and H4K12, thereby modulating the transcriptional programs driving neuroinflammation and AD pathology. These findings illustrate that CD31 may act as a promising target for creating novel therapeutic strategies.

Abstract Microglia play crucial roles in Alzheimer’s disease (AD), yet the molecular mechanisms are unclear. Here, we show that CD31, a recognized endothelial marker, is predominantly expressed in microglia but not in neurons or astrocytes, and it is significantly elevated in the brains of AD patients and mouse models. Microglia-specific CD31 knockdown in 5xFAD mice substantially attenuated the dysregulated transcription networks, suppressed microglia hyperactivation and the disease-associated microglia (DAM), mitigated Aβ deposition and inflammation, and eventually improved cognitive functions in mice. Mechanistically, CD31 knockdown damaged the simultaneous recruitment of Src homology phosphatase 2 (SHP2) and STAT3, leading to a reduced dephosphorylation and enhanced activation of STAT3, a transcription factor. STAT3 activation increased transcription of membrane metalloendopeptidase (MME) and promoted Aβ clearance. Collectively, this study identifies microglial CD31, by regulating SHP2–STAT3–MME axis, plays a role in AD pathogenesis and targeting CD31 is promising in AD drug development.

The loss of astrocytes represents a key pathological hallmark of major depressive disorder, yet its mechanisms remain elusive. Here, we identified NDRG2 as a critical regulator of astrocyte apoptosis in depression. NDRG2 expression is upregulated in depression models, concomitant with astrocyte loss. Overexpression of NDRG2 in astrocytes triggered apoptosis and depressive-like behaviors, with inhibition of AKT and activation of FoxO3a-Puma apoptotic signaling pathway. Mechanistically, NDRG2 recruits PP2A to AKT, facilitating its dephosphorylation and subsequent inactivation, then promotes the nuclear translocation of FoxO3a, leading to the transcriptional activation of the pro-apoptotic factor Puma. Crucially, NDRG2 knockdown in astrocytes effectively prevented astrocytic apoptosis, with effective rescue of depressive-like phenotypes. These findings reveal a key mechanism of astrocyte death in depression, wherein NDRG2 functions as an adaptor to promote PP2A-mediated AKT dephosphorylation, thereby initiating the pro-apoptotic signaling pathway, and disclose a druggable pathway for developing antidepressants targeting astrocyte preservation.

Intraneuronal accumulation of hyperphosphorylated tau is a hallmark of Alzheimer’s disease (AD). Given the significant correlation between tau pathology and memory loss in AD patients, identifying vulnerable brain regions, particularly susceptible neuron types in these regions, will advance our understanding of AD onset and shed light on therapeutic strategies to manage its progression. Immunofluorescent staining was employed to identify the brain regions and neuron types vulnerable to tau pathology in AD. A combination of chemogenetics, electrophysiological recording, in vivo Ca2+ recording, and a modified temporal-order discrimination behavior test was utilized to investigate the toxicity of tau accumulation to susceptible neurons in the dorsal part of the ventral hippocampus. Proteomics, phosphoproteomics, and molecular targeting were used to explore the underlying mechanisms of neuron susceptibility to tau accumulation in AD. The beneficial effects of microtubule affinity regulating kinase 4 (MARK4) knockdown and administration of DEPhosphorylation TArgeting Chimera (DEPTAC) were evaluated in AD mice with tau pathology. In postmortem brains of AD patients, we observed robust accumulation of hyperphosphorylated tau in the anterior hippocampal CA1 region, particularly in its Calbindin1− (Calb1−) neurons, as opposed to the posterior hippocampal CA1 region and Calb1+ neurons. The susceptibility of Calb1− neurons to phospho-tau accumulation was also observed in P301L mice, especially in the dorsal part of ventral (anterior in human) hippocampal CA1 (dvCA1). In P301L mice, dvCA1 displayed distinct protein and phosphorylated protein networks compared with dorsal CA1, accompanied by overactivation of MARK4. Overexpressing human tau in Calb1− neurons in the dvCA1 (dvCA1Calb1− neurons) specifically impairs the temporal-order discrimination of objects. Meanwhile, tau accumulation significantly inhibited the excitability and firing patterns of dvCA1Calb1− neurons associated with temporal-order discrimination. Knocking down MARK4 or reducing hyperphosporylated tau via DEPTAC in P301L mice significantly ameliorated AD-like tau pathology in dvCA1Calb1− neurons and improved temporal-order discrimination of objects. These findings highlight the crucial role of dvCA1Calb1− neurons in the early stage of tau pathology and demonstrate the potential of targeting phosphorylated tau through MARK4 knockdown or DEPTAC administration to counter the vulnerability of dvCA1Calb1− neurons and, consequently, ameliorate episodic memory deficits in AD.

Background Episodic memory loss is a prominent clinical manifestation of Alzheimer’s disease (AD), which is closely related to tau pathology and hippocampal impairment. Due to the heterogeneity of brain neurons, the specific roles of different brain neurons in terms of their sensitivity to tau accumulation and their contribution to AD-like social memory loss remain unclear. Therefore, further investigation is necessary. Methods We investigated the effects of AD-like tau pathology by Tandem mass tag proteomic and phosphoproteomic analysis, social behavioural tests, hippocampal electrophysiology, immunofluorescence staining and in vivo optical fibre recording of GCaMP6f and iGABASnFR. Additionally, we utilized optogenetics and administered ursolic acid (UA) via oral gavage to examine the effects of these agents on social memory in mice. Results The results of proteomic and phosphoproteomic analyses revealed the characteristics of ventral hippocampal CA1 (vCA1) under both physiological conditions and AD-like tau pathology. As tau progressively accumulated, vCA1, especially its excitatory and parvalbumin (PV) neurons, were fully filled with mislocated and phosphorylated tau (p-Tau). This finding was not observed for dorsal hippocampal CA1 (dCA1). The overexpression of human tau (hTau) in excitatory and PV neurons mimicked AD-like tau accumulation, significantly inhibited neuronal excitability and suppressed distinct discrimination-associated firings of these neurons within vCA1. Photoactivating excitatory and PV neurons in vCA1 at specific rhythms and time windows efficiently ameliorated tau-impaired social memory. Notably, 1 month of UA administration efficiently decreased tau accumulation via autophagy in a transcription factor EB (TFEB)-dependent manner and restored the vCA1 microcircuit to ameliorate tau-impaired social memory. Conclusion This study elucidated distinct protein and phosphoprotein networks between dCA1 and vCA1 and highlighted the susceptibility of the vCA1 microcircuit to AD-like tau accumulation. Notably, our novel findings regarding the efficacy of UA in reducing tau load and targeting the vCA1 microcircuit may provide a promising strategy for treating AD in the future.

Nowadays, effective prognostic models for esophageal cancer (ESCA) are still lacking. Long noncoding RNAs (lncRNAs) are commonly utilized as indicators for diagnosing cancer and forecasting patient outcomes. Cuproptosis is regulated by multiple genes and is crucial to the progression of ESCA. However, it is not yet clear what role the cuproptosis-associated lncRNAs (CuALs) play in ESCA. To tackle this problem, a prognostic signature incorporating three CuALs was created. This signature was constructed by the use of the least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression. Subsequently, the signature effectively stratified ESCA samples into a high-risk group and a low-risk group. Those in the low-risk group demonstrated extended overall survival (OS), as well as increased infiltration of T cells, macrophages, and NK cells, suggesting a potentially enhanced response to immunotherapy. The ROC curve analysis demonstrated that this prognostic signature outperformed conventional clinical factors in predicting patient prognosis (AUC = 0.708). K-M survival analysis and correlation analysis identified UGDH-AS1 (a CuAL) as a protective factor positively associated with patient prognosis. The results of RT-qPCR and wound healing assays indicated that UGDH-AS1 is overexpressed in ESCA and could inhibit cancer cell migration. In general, the prognostic signature of CuALs demonstrated a robust capability in forecasting the immune environment and patient prognosis, highlighting its potential as a tool for enhancing personalized treatment strategies in ESCA.

Background: The prevalence of Alzheimer’s disease (AD) is increasing, therefore, identifying biomarkers to predict those vulnerable to AD is imperative. Type 2 diabetes (T2D) serves as an independent risk factor for AD. Early prediction of T2D patients who may be more susceptible to AD, so as to achieve early intervention, is of great significance to reduce the prevalence of AD. Objective: To establish periphery biomarkers that could predict conversion of T2D into pre-AD-like cognitive decline. Methods: A follow-up study was carried out from 159 T2D patients at baseline. The correlations of cognitive states (by MMSE score) with multi-periphery biomarkers, including APOE genotype, plasma amyloid-β level, platelet GSK-3β activity, and olfactory score were analyzed by logistic regression. ROC curve was used for establishing the prediction model. Additionally, MRI acquired from 38 T2D patients for analyzing the correlation among cognitive function, biomarkers and brain structure. Results: Compared with the patients who maintained normal cognitive functions during the follow-up period, the patients who developed MCI showed worse olfactory function, higher platelet GSK-3β activity, and higher plasma Aβ42/Aβ40 ratio. We conducted a predictive model which T2D patients had more chance of suffering from pre-AD-like cognitive decline. The MRI data revealed MMSE scores were positively correlated with brain structures. However, platelet GSK-3β activity was negatively correlated with brain structures. Conclusions: Elevated platelet GSK-3β activity and plasma Aβ42/Aβ40 ratio with reduced olfactory function are correlated with pre-AD-like cognitive decline in T2D patients, which used for predicting which T2D patients will convert into pre-AD-like cognitive decline in very early stage.

After aversive stress, people either choose to return to their previously familiar social environment or tend to adopt temporary social withdrawal to buffer negative emotions. However, which behavior intervention is more appropriate and when remain elusive. Here, we unexpectedly found that stressed mice experiencing social isolation exhibited less anxiety than those experiencing social contact. Within the first 24 h after returning to their previous social environment, mice experienced acute restraint stress (ARS) displayed low social interest but simultaneously received excessive social disturbance from their cage mates, indicating a critical time window for social isolation to balance the conflict. To screen brain regions that were differentially activated between the poststress social isolation and poststress social contact groups, we performed ΔFosB immunostaining and found that ΔFosB + signals were remarkably increased in the vDG of poststress social isolation group compared with poststress social contact group. There were no significant differences between the two groups in the other anxiety- and social-related brain regions, such as prelimbic cortex, infralimbic cortex, nucleus accumbens, etc. These data indicate that vDG is closely related to the differential phenotypes between the poststress social isolation and poststress social contact groups. Electrophysiological recording, further, revealed a higher activity of vDG in the poststress social isolation group than the poststress social contact group. Chemogenetically inhibiting vDG excitatory neurons within the first 24 h after ARS completely abolished the anxiolytic effects of poststress social isolation, while stimulating vDG excitatory neurons remarkably reduced anxiety-like behaviors in the poststress social contact group. Together, these data suggest that the activity of vDG excitatory neurons is essential and sufficient to govern the anxiolytic effect of poststress social isolation. To the best of our knowledge, this is the first report to uncover a beneficial role of temporal social isolation in acute stress-induced anxiety. In addition to the critical 24-h time window, activation of vDG is crucial for ameliorating anxiety through poststress social isolation.

Objective:To investigate the variation of ferroptosis-related markers in HaCaT cell photoaging models induced by ultraviolet-B (UVB).Methods:UVB-treated HaCaT cells served as the model (UVB group) for cellular photoaging, whereas untreated HaCaT cells served as the control group. HaCaT cells were exposed to UVB and the ferroptosis inhibitor Ferrostatin-1 (Fer-1) as part of the UVB+Fer-1 group, and co-cultured with the ferroptosis inducer Erastin as part of the UVB+Erastin group. Reactive oxygen species (ROS) detection kit and senescence-related β galactosidase (SA-β-gal) staining were used to evaluate the senescence of HaCaT cells. Lipid reactive oxygen species were detected by C11 BODIPY581/591 probe and mitochondrial morphology was observed by transmission electron microscopy. The mRNA expressions of glutathione peroxidase 4 (GPX4) and ferroptosis-suppressor-protein 1 (FSP1) were detected by real-time reverse transcription-PCR (RT-RCP), and the level of GPX4 protein was measured by immunofluorescence assay.Results:The UVB group had considerably greater levels of ROS, SA-β-gal, and lipid reactive oxygen species than the control group. The UVB group's mitochondrial volume was reduced, the membrane density increased, and the mitochondrial crest decreased or even disappeared. GPX4 and FSP1 expression levels were similarly found to be lower in the UVB group. Furthermore, the positive rate of SA-β-gal and lipid reactive oxygen species in the UVB+Fer-1 group was much lower than in the UVB group, but it was reverse in the UVB+Erastin group. This study showed that induced ferroptosis can aggravate aging, and vice versa.Conclusion:According to the findings, ferroptosis may be linked to UVB-induced skin photoaging, which could be attenuated by inhibition of ferroptosis.

19 After aversive stress, people either choose to return to their previously familiar social 20 environment or tend to adopt temporary social withdrawal to buffer negative emotions. 21 However, which behavior intervention is more appropriate and when remain elusive. 22 Here, we unexpectedly found that stressed mice experiencing social isolation exhibited 23 less anxiety than those experiencing social contact. Within the first 24 h after returning 24 to their previous social environment, mice experienced acute restraint stress (ARS) 25 displayed low social interest but simultaneously received excessive social disturbance 26 from their cage mates, indicating a critical time window for social isolation to balance 27 the conflict. To screen brain regions that were differentially activated between the 28 poststress social isolation and poststress social contact groups, we performed ΔFosB 29 immunostaining and found that ΔFosB+ signals were remarkably increased in the vDG 30 of poststress social isolation group compared with poststress social contact group. 31 There were no significant differences between the two groups in the other anxiety- and 32 social- related brain regions, such as prelimbic cortex, infralimbic cortex, nucleus 33 accumbens, etc.. These data indicate that vDG is closely related to the differential 34 phenotypes between the poststress social isolation and poststress social contact groups. 35 Electrophysiological recording, further, revealed a higher activity of vDG in the 36 poststress social isolation group than the poststress social contact group. 37 Chemogenetically inhibiting vDG excitatory neurons within the first 24 h after ARS 38 completely abolished the anxiolytic effects of poststress social isolation, while 39 stimulating vDG excitatory neurons remarkably reduced anxiety-like behaviors in the 40 poststress social contact group. Together, these data suggest that the activity of vDG 41 excitatory neurons is essential and sufficient to govern the anxiolytic effect of poststress 42 social isolation. To the best of our knowledge, this is the first report to uncover a 43 beneficial role of temporal social isolation in acute stress-induced anxiety. In addition 44 to the critical 24-h time window, activation of vDG is crucial for ameliorating anxiety 45 through poststress social isolation.

Diabetes is a common chronic metabolic disease, and its incidence continues to increase year after year. Diabetic patients mainly die from various complications, with the most common being diabetic cardiomyopathy. However, the detection rate of diabetic cardiomyopathy is low in clinical practice, and targeted treatment is lacking. Recently, a large number of studies have confirmed that myocardial cell death in diabetic cardiomyopathy involves pyroptosis, apoptosis, necrosis, ferroptosis, necroptosis, cuproptosis, cellular burial, and other processes. Most importantly, numerous animal studies have shown that the onset and progression of diabetic cardiomyopathy can be mitigated by inhibiting these regulatory cell death processes, such as by utilizing inhibitors, chelators, or genetic manipulation. Therefore, we review the role of ferroptosis, necroptosis, and cuproptosis, three novel forms of cell death in diabetic cardiomyopathy, searching for possible targets, and analyzing the corresponding therapeutic approaches to these targets.

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are the most serious and common diabetes-associated complications. DN and DR are all highly prevalent and dangerous global diseases, but the underlying mechanism remains to be elucidated. Ferroptosis, a relatively recently described type of cell death, has been confirmed to be involved in the occurrence and development of various diabetic complications. The disturbance of cellular iron metabolism directly triggers ferroptosis, and abnormal iron metabolism is closely related to diabetes. However, the molecular mechanism underlying the role of ferroptosis in DN and DR is still unclear, and needs further study. In this review article, we summarize and evaluate the mechanism of ferroptosis and its role and progress in DN and DR, it provides new ideas for the diagnosis and treatment of DN and DR.

Background: Olfactory dysfunction appears prior to cognitive decline, and thus it has been suggested to be an early predictor of Alzheimer’s disease. However, it is currently not known whether and how olfactory threshold test could serve as a quick screening tool for cognitive impairment. Objective: To define olfactory threshold test for screening cognitive impairment in two independent cohorts. Methods: The participants are comprised of two cohorts in China, 1,139 inpatients with type 2 diabetes mellitus (T2DM, Discovery cohort) and 1,236 community-dwelling elderly (Validation cohort). Olfactory and cognitive functions were evaluated by Connecticut Chemosensory Clinical Research Center test and Mini-Mental State Examination (MMSE), respectively. Regression analyses and receiver operating characteristic (ROC) analyses were carried out to determine the relation and discriminative performance of the olfactory threshold score (OTS) regarding identification of cognition impairment. Results: Regression analysis showed that olfactory deficit (reducing OTS) was correlated with cognitive impairment (reducing MMSE score) in two cohorts. ROC analysis revealed that the OTS could distinguish cognitive impairment from cognitively normal individuals, with mean area under the curve values of 0.71 (0.67, 0.74) and 0.63 (0.60, 0.66), respectively, but it failed to discriminate dementia from mild cognitive impairment. The cut-off point of 3 showed the highest validity for the screening, with the diagnostic accuracy of 73.3% and 69.5%. Conclusion: Reducing OTS is associated with cognitive impairment in T2DM patients and the community-dwelling elderly. Therefore, olfactory threshold test may be used as a readily accessible screening tool for cognitive impairment.

Diabetes mellitus is a metabolic disease that is characterized by chronic hyperglycemia due to a variety of etiological factors. Long-term metabolic stress induces harmful inflammation leading to chronic complications, mainly diabetic ophthalmopathy, diabetic cardiovascular complications and diabetic nephropathy. With diabetes complications being one of the leading causes of disability and death, the use of anti-inflammatories in combination therapy for diabetes is increasing. There has been increasing interest in targeting significant regulators of the inflammatory pathway, notably receptor-interacting serine/threonine-kinase-1 (RIPK1) and receptor-interacting serine/threonine-kinase-3 (RIPK3), as drug targets for managing inflammation in treating diabetes complications. In this review, we aim to provide an up-to-date summary of current research on the mechanism of action and drug development of RIPK1 and RIPK3, which are pivotal in chronic inflammation and immunity, in relation to diabetic complications which may be benefit for explicating the potential of selective RIPK1 and RIPK3 inhibitors as anti-inflammatory therapeutic agents for diabetic complications.

Abstract Background Human Tau (hTau) accumulation and synapse loss are two pathological hallmarks of tauopathies. However, whether and how hTau exerts toxic effects on synapses remain elusive. Methods Mutated hTau (P301S) was overexpressed in the N2a cell line, primary hippocampal neurons and hippocampal CA3. Western blotting and quantitative polymerase chain reaction were applied to examine the protein and mRNA levels of synaptic proteins. The protein interaction was tested by co‐immunoprecipitation and proximity ligation assays. Memory and emotion status were evaluated by a series of behavioural tests. The transcriptional activity of nuclear factor‐erythroid 2–related factor 2 (NRF2) was detected by dual luciferase reporter assay. Electrophoresis mobility shift assay and chromosome immunoprecipitation were conducted to examine the combination of NRF2 to specific anti‐oxidative response element (ARE) sequences. Neuronal morphology was analysed after Golgi staining. Results Overexpressing P301S decreased the protein levels of post‐synaptic density protein 93 (PSD93), PSD95 and synapsin 1 (SYN1). Simultaneously, NRF2 was decreased, whereas Kelch‐like ECH‐associated protein 1 (KEAP1) was elevated. Further, we found that NRF2 could bind to the specific AREs of DLG2, DLG4 and SYN1 genes, which encode PSD93, PSD95 and SYN1, respectively, to promote their expression. Overexpressing NRF2 ameliorated P301S‐reduced synaptic proteins and synapse. By means of acetylation at K312, P301S increased the protein level of KEAP1 via inhibiting KEAP1 degradation from ubiquitin–proteasome pathway, thereby decreasing NRF2 and reducing synapse. Blocking the P301S–KEAP1 interaction at K312 rescued the P301S‐suppressed expression of synaptic proteins and memory deficits with anxiety efficiently. Conclusions P301S‐hTau could acetylate KEAP1 to trigger synaptic toxicity via inhibiting the NRF2/ARE pathway. These findings provide a novel and potential target for the therapeutic intervention of tauopathies.

Type 2 diabetes mellitus (T2DM) is an independent risk factor of Alzheimer’s disease (AD), and thus identifying who among the increasing T2DM populations may develop into AD is important for early intervention. By using TMT-labeling coupled high-throughput mass spectrometry, we conducted a comprehensive plasma proteomic analysis in none-T2DM people (Ctrl, n = 30), and the age-/sex-matched T2DM patients with mild cognitive impairment (T2DM-MCI, n = 30) or T2DM without MCI (T2DM-nMCI, n = 25). The candidate biomarkers identified by proteomics and bioinformatics analyses were verified by ELISA, and their diagnostic capabilities were evaluated with machine learning. A total of 53 differentially expressed proteins (DEPs) were identified in T2DM-MCI compared with T2DM-nMCI patients. These DEPs were significantly enriched in multiple biological processes, such as amyloid neuropathies, CNS disorders, and metabolic acidosis. Among the DEPs, alpha-1-antitrypsin (SERPINA1), major viral protein (PRNP), and valosin-containing protein (VCP) showed strong correlation with AD high-risk genes APP, MAPT, APOE, PSEN1, and PSEN2. Also, the levels of PP2A cancer inhibitor (CIP2A), PRNP, corticotropin-releasing factor-binding protein (CRHBP) were significantly increased, while the level of VCP was decreased in T2DM-MCI patients compared with that of the T2DM-nMCI, and these changes were correlated with the Mini-Mental State Examination (MMSE) score. Further machine learning data showed that increases in PRNP, CRHBP, VCP, and rGSK-3β(T/S9) (ratio of total to serine-9-phosphorylated glycogen synthase kinase-3β) had the greatest power to identify mild cognitive decline in T2DM patients.

Generalization is a fundamental cognitive ability of organisms to deal with the uncertainty in real-world situations. Excessive fear generalization and impaired reward generalization are closely related to many psychiatric disorders. However, the neural circuit mechanism for reward generalization and its role in anxiety-like behaviours remain elusive. Here, we found a robust activation of calbindin 1-neurons (Calb 1) in the posterior basolateral amygdala (pBLA), simultaneous with reward generalization to an ambiguous cue after reward conditioning in mice. We identify the infralimbic medial prefrontal cortex (IL) to the pBLA Calb1 (Calb 1 neurons in the pBLA) pathway as being involved in reward generalization for the ambiguity. Activating IL–pBLA inputs strengthens reward generalization and reduces chronic unpredictable mild stress-induced anxiety- and depression-like behaviours in a manner dependent on pBLA Calb1 neuron activation. These findings suggest that the IL–pBLA Calb1 circuit could be a target to promote stress resilience via reward generalization and consequently ameliorate anxiety- and depression-like behaviours.

Objective: The aim of this study was to use network pharmacology to explore the potential targets and mechanisms of action of Qibao Meiran Dan in relation to delaying skin aging. Methods: The traditional Chinese medicine systems pharmacology database and analysis platform, and the traditional Chinese medicine integrated database, were used to screen the active ingredients and targets of Qibao Meiran Dan. The human gene database GeneCards and the gene database of the National Center for Biotechnology Information were jointly adopted to obtain skin aging-related target genes. The search tool for the retrieval of interacting genes/proteins (STRING) database was used for core analysis of protein-protein interaction. Results: In total, 72 effective active ingredients, 273 action targets, 234 skin aging target genes, and 64 intersecting core targets were identified. GO enrichment analysis provided 393 biological process entries, and the KEGG analysis was represented by the tumor necrosis factor (TNF) signaling pathway, where the core targets of TNF-alpha and matrix metalloproteinase-1 (MMP-1) were enriched. The experimental results showed that cell morphology was clearer and more refractive in the Qibao Meiran Dan group than in the model group. Conclusion: Qibao Meiran Dan may regulate oxidative stress injury and collagen metabolism by downregulating the expression of TNF-alpha and MMP-1, thus slowing skin aging.

BACKGROUND:Glycogen synthase kinase-3β (GSK-3β) is one of the most effective kinases in promoting tau hyperphosphorylation and accumulation in Alzheimer's disease (AD). However, it is not clear how GSK-3β activity is regulated during AD progression.METHODS:We firstly used mass spectrometry to identify the acetylation site of GSK-3β, and then established the cell and animal models of GSK-3β acetylation. Next, we conducted molecular, cell biological and behavioral tests. Finally, we designed a peptide to test whether blocking tau-mediated GSK-3β acetylation could be beneficial to AD.FINDINGS:We found that GSK-3β protein levels increased in the brains of AD patients and the transgenic mice. Overexpressing tau increased GSK-3β protein level with increased acetylation and decreased ubiquitination-related proteolysis. Tau could directly acetylate GSK-3β at K15 both in vitro and in vivo. K15-acetylation inhibited ubiquitination-associated proteolysis of GSK-3β and changed its activity-dependent phosphorylation, leading to over-activation of the kinase. GSK-3β activation by K15-acetylation in turn exacerbated the AD-like pathologies. Importantly, competitively inhibiting GSK-3β K15-acetylation by a novel-designed peptide remarkably improved cognitive impairment and the AD-like pathologies in 3xTg-AD mice.INTERPRETATION:Tau can directly acetylate GSK-3β at K15 which reveals a vicious cycle between tau hyperphosphorylation and GSK-3β activation.FUNDING:This study was supported in parts by grants from Science and Technology Committee of China (2016YFC1305800), Hubei Province (2018ACA142), Natural Science Foundation of China (91949205, 82001134, 31730035, 81721005), Guangdong Provincial Key S&T Program (018B030336001).

Background Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease (AD). This study aimed to investigate whether and how the accumulating tau may in turn affect autophagy. Methods The primary hippocampal neurons, N2a and HEK293T cells with tau overexpression were respectively starved and treated with vinblastine to study the effects of tau on the initiating steps of autophagy, which was analysed by Student's two-tailed t -test. The rapamycin and concanamycin A were employed to inhibit the mammalian target of rapamycin kinase complex 1 (mTORC1) activity and the vacuolar H + -ATPase (v-ATPase) activity, respectively, which were analysed by One‐way ANOVA with post hoc tests. The Western blotting, co-immunoprecipitation and immunofluorescence staining were conducted to gain insight into the mechanisms underlying the tau effects of mTORC1 signaling alterations, as analysed by Student's two-tailed t -test or One‐way ANOVA with post hoc tests. The autophagosome formation was detected by immunofluorescence staining and transmission electron microscopy. The amino acids (AA) levels were detected by high performance liquid chromatography (HPLC). Results We observed that overexpressing human full-length wild-type tau to mimic AD-like tau accumulation induced autophagy deficits. Further studies revealed that the increased tau could bind to the prion-related domain of T cell intracellular antigen 1 (PRD-TIA1) and this association significantly increased the intercellular level of amino acids (Leucine, P = 0.0038; Glutamic acid, P = 0.0348; Alanine, P = 0.0037; Glycine, P = 0.0104), with concordant upregulation of mTORC1 activity [phosphorylated eukaryotic translation initiation factor 4E-binding protein 1 (p-4EBP1), P < 0.0001; phosphorylated 70 kDa ribosomal protein S6 kinase 1 (p-p70S6K1), P = 0.0001, phosphorylated unc-51-like autophagy-activating kinase 1 (p-ULK1), P = 0.0015] and inhibition of autophagosome formation [microtubule-associated protein light chain 3 II (LC3 II), P = 0.0073; LC3 puncta, P < 0.0001]. As expected, this tau-induced deficit of autophagosome formation in turn aggravated tau accumulation. Importantly, we also found that blocking TIA1 and tau interaction by overexpressing PRD-TIA1, downregulating the endogenous TIA1 expression by shRNA, or downregulating tau protein level by a small proteolysis targeting chimera (PROTAC) could remarkably attenuate tau-induced autophagy impairment. Conclusions Our findings reveal that AD-like tau accumulation inhibits autophagosome formation and induces autophagy deficits by activating the TIA1/amino acid/mTORC1 pathway, and thus this work reveals new insight into tau-associated neurodegeneration and provides evidence supporting the use of new therapeutic targets for AD treatment and that of related tauopathies.