14-3-3 proteins in the nervous system

The mechanism of 14-3-3η in thyroxine induced mitophagy in cardiomyocytes

Hyperthyroidism is becoming increasingly important as an independent risk factor for cardiovascular disease, eventually resulting in cardiac hypertrophy and heart failure. The 14-3-3 protein family subtypes regulate many cellular processes in eukaryotes by interacting with a diverse array of client proteins. Considering that the 14-3-3η protein protects cardiomyocytes by affecting mitochondrial function, exploring the biological influence and molecular mechanisms by which 14-3-3η alleviates the cardiac hypertrophy of hyperthyroidism is imperative. In vivo and in vitro, RT-PCR, Western blot, and Mitochondrial tracking assay were performed to understand the molecular mechanism of thyroxine-induced cardiomyocyte hypertrophy. HE staining, transmission electron microscopy, and immunofluorescence were used to observe intuitively changes of hearts and cardiomyocytes. The in vivo and in vitro results indicated that overexpression of the 14-3-3η ameliorated thyroxine-induced cardiomyocyte hypertrophy, whereas knockdown of the 14-3-3η protein aggravated thyroxine-induced cardiomyocyte hypertrophy. Additionally, overexpression of the 14-3-3η protein reduces thyroxine-induced mitochondrial damage and mitophagy in cardiomyocytes. Overexpression of 14-3-3η protein improves excessive mitophagy in the myocardium caused by thyroxine and thus prevents cardiac hypertrophy.

Role of 14-3-3 protein family in the pathobiology of EBV in immortalized B cells and Alzheimer's disease

Background and Aims

Several studies have revealed that Epstein-Barr virus (EBV) infection raised the likelihood of developing Alzheimer's disease (AD) via infecting B lymphocytes. The purpose of the current investigation was to assess the possible association between EBV infection and AD.

Methods

The microarray datasets GSE49628, GSE126379, GSE122063, and GSE132903 were utilized to extract DEGs by using the GEO2R tool of the GEO platform. The STRING tool was used to determine the interaction between the DEGs, and Cytoscape was used to visualize the results. The DEGs that were found underwent function analysis, including pathway and GO, using the DAVID 2021 and ClueGo/CluePedia. By using MNC, MCC, Degree, and Radiality of cytoHubba, we identified seven common key genes. Gene co-expression analysis was performed through the GeneMANIA web tool. Furthermore, expression analysis of key genes was performed through GTEx software, which have been identified in various human brain regions. The miRNA-gene interaction was performed through the miRNet v 2.0 tool. DsigDB on the Enrichr platform was utilized to extract therapeutic drugs connected to key genes.

Results

In GEO2R analysis of datasets with |log2FC|≥ 0.5 and p-value <0.05, 8386, 10,434, 7408, and 759 genes were identified. A total of 141 common DEGs were identified by combining the extracted genes of different datasets. A total of 141 nodes and 207 edges were found during the PPI analysis. The DEG GO analysis with substantial alterations disclosed that they are associated to molecular functions and biological processes, such as positive regulation of neuron death, autophagy regulation of mitochondrion, response of cell to insulin stimulus, calcium signaling regulation, organelle transport along microtubules, protein kinase activity, and phosphoserine binding. Kyoto Encyclopedia of Genes and Genomes analysis discovered the correlation between the DEGs in pathways of neurodegeneration: multiple disease, cell cycle, and cGMP-PKG signaling pathway. Finally, YWHAH, YWHAG, YWHAB, YWHAZ, MAP2K1, PPP2CA, and TUBB genes were identified that are strongly linked to EBV and AD. Three miRNAs, i.e., hsa-mir-15a-5p, hsa-let-7a-5p, and hsa-mir-7-5p, were identified to regulate most of hub genes that are associated with EBV and AD. Further top 10 significant therapeutic drugs were predicted.

Conclusion

We have discovered new biomarkers and therapeutic targets for AD, as well as the possible biological mechanisms whereby infection with EBV may be involved in AD susceptibility for the first time.

14-3-3 Family of Proteins: Biological Implications, Molecular Interactions, and Potential Intervention in Cancer, Virus and Neurodegeneration Disorders

The 14-3-3 family of proteins are highly conserved acidic eukaryotic proteins (25-32 kDa) abundantly present in the body. Through numerous binding partners, the 14-3-3 is responsible for many essential cellular pathways, such as cell cycle regulation and gene transcription control. Hence, its dysregulation has been linked to the onset of critical illnesses such as cancers, neurodegenerative diseases and viral infections. Interestingly, explorative studies have revealed an inverse correlation of 14-3-3 protein in cancer and neurodegenerative diseases, and the direct manipulation of 14-3-3 by virus to enhance infection capacity has dramatically extended its significance. Of these, COVID-19 has been linked to the 14-3-3 proteins by the interference of the SARS-CoV-2 nucleocapsid (N) protein during virion assembly. Given its predisposition towards multiple essential host signalling pathways, it is vital to understand the holistic interactions between the 14-3-3 protein to unravel its potential therapeutic unit in the future. As such, the general structure and properties of the 14-3-3 family of proteins, as well as their known biological functions and implications in cancer, neurodegeneration, and viruses, were covered in this review. Furthermore, the potential therapeutic target of 14-3-3 proteins in the associated diseases was discussed.

14-3-3τ as a Modulator of Early α-Synuclein Multimerization and Amyloid Formation

The aggregation of α-synuclein (αS) plays a key role in Parkinson's disease (PD) etiology. While the onset of PD is age-related, the cellular quality control system appears to regulate αS aggregation throughout most human life. Intriguingly, the protein 14-3-3τ has been demonstrated to delay αS aggregation and the onset of PD in various models. However, the molecular mechanisms behind this delay remain elusive. Our study confirms the delay in αS aggregation by 14-3-3τ, unveiling a concentration-dependent relation. Utilizing microscale thermophoresis (MST) and single-molecule burst analysis, we quantified the early αS multimers and concluded that these multimers exhibit properties that classify them as nanoscale condensates that form in a cooperative process, preceding the critical nucleus for fibril formation. Significantly, the αS multimer formation mechanism changes dramatically in the presence of scaffold protein 14-3-3τ. Our data modeling suggests that 14-3-3τ modulates the multimerization process, leading to the creation of mixed multimers or co-condensates, comprising both αS and 14-3-3τ. These mixed multimers form in a noncooperative process. They are smaller, more numerous, and distinctively not on the pathway to amyloid formation. Importantly, 14-3-3τ thus acts in the very early stage of αS multimerization, ensuring that αS does not aggregate but remains soluble and functional. This offers long-sought novel entries for the pharmacological modulation of PD.

Targeting 14-3-3θ-mediated TDP-43 pathology in amyotrophic lateral sclerosis and frontotemporal dementia mice

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are characterized by cytoplasmic deposition of the nuclear TAR-binding protein 43 (TDP-43). Although cytoplasmic re-localization of TDP-43 is a key event in the pathogenesis of ALS/FTD, the underlying mechanisms remain unknown. Here, we identified a non-canonical interaction between 14-3-3θ and TDP-43, which regulates nuclear-cytoplasmic shuttling. Neuronal 14-3-3θ levels were increased in sporadic ALS and FTD with TDP-43 pathology. Pathogenic TDP-43 showed increased interaction with 14-3-3θ, resulting in cytoplasmic accumulation, insolubility, phosphorylation, and fragmentation of TDP-43, resembling pathological changes in disease. Harnessing this increased affinity of 14-3-3θ for pathogenic TDP-43, we devised a gene therapy vector targeting TDP-43 pathology, which mitigated functional deficits and neurodegeneration in different ALS/FTD mouse models expressing mutant or non-mutant TDP-43, including when already symptomatic at the time of treatment. Our study identified 14-3-3θ as a mediator of cytoplasmic TDP-43 localization with implications for ALS/FTD pathogenesis and therapy.

CSF 14-3-3 zeta(ζ) isoform is associated with tau pathology and cognitive decline in Alzheimer's disease

14-3-3 is a family of conserved proteins that consist of seven isoforms which are highly expressed in the brain, and 14-3-3 zeta(ζ) is one of the isoforms encoded by the YWHAZ gene. Previous studies demonstrated that 14-3-3ζ is deposited in the neurofibrillary tangles of Alzheimer's disease (AD) brains, and that 14-3-3ζ interacts with tau from the purified neurofibrillary tangles of AD brain extract. The present study examined the cerebrospinal fluid (CSF) 14-3-3ζ levels of 719 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI), including cognitively normal (CN) participants, patients with mild cognitive impairment (MCI) and patients with AD dementia, and aimed to identify whether CSF 14-3-3ζ is associated with tau pathology. CSF 14-3-3ζ levels were increased in AD, and particularly elevated among tau pathology positive individuals. CSF 14-3-3ζ levels were associated with CSF phosphorylated tau 181 (p-tau) (r = 0.741, P < 0.001) and plasma p-tau (r = 0.293, P < 0.001), which are fluid biomarkers of tau pathology, and could predict tau pathology positive status with high accuracy (area under the receiver operating characteristic curve [AUC], 0.891). CSF 14-3-3ζ levels were also correlated to synaptic biomarker CSF GAP-43 (r = 0.609, P < 0.001) and neuroinflammatory biomarker CSF sTREM-2 (r = 0.507, P < 0.001). High CSF 14-3-3ζ levels at baseline were associated with progressive decline of cognitive function and neuroimaging findings during follow up. In conclusion, this study suggests that CSF 14-3-3ζ is a potential biomarker of AD that may be useful in clinical practice.

Modus operandi: Chromatin recognition by α-helical histone readers

Histone reader domains provide a mechanism for sensing states of coordinated nuclear processes marked by histone proteins' post-translational modifications (PTMs). Among a growing number of discovered histone readers, the 14-3-3s, ankyrin repeat domains (ARDs), tetratricopeptide repeats (TPRs), bromodomains (BRDs), and HEAT domains are a group of domains using various mechanisms to recognize unmodified or modified histones, yet they all are composed of an α-helical fold. In this review, we compare how these readers fold to create protein domains that are very diverse in their tertiary structures, giving rise to intriguing peptide binding mechanisms resulting in vastly different footprints of their targets.

Dysregulation of extracellular vesicle protein cargo in female myalgic encephalomyelitis/chronic fatigue syndrome cases and sedentary controls in response to maximal exercise

In healthy individuals, physical exercise improves cardiovascular health and muscle strength, alleviates fatigue and reduces the risk of chronic diseases. Although exercise is suggested as a lifestyle intervention to manage various chronic illnesses, it negatively affects people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), who suffer from exercise intolerance. We hypothesized that altered extracellular vesicle (EV) signalling in ME/CFS patients after an exercise challenge may contribute to their prolonged and exacerbated negative response to exertion (post-exertional malaise). EVs were isolated by size exclusion chromatography from the plasma of 18 female ME/CFS patients and 17 age- and BMI-matched female sedentary controls at three time points: before, 15 min, and 24 h after a maximal cardiopulmonary exercise test. EVs were characterized using nanoparticle tracking analysis and their protein cargo was quantified using Tandem Mass Tag-based (TMT) proteomics. The results show that exercise affects the EV proteome in ME/CFS patients differently than in healthy individuals and that changes in EV proteins after exercise are strongly correlated with symptom severity in ME/CFS. Differentially abundant proteins in ME/CFS patients versus controls were involved in many pathways and systems, including coagulation processes, muscle contraction (both smooth and skeletal muscle), cytoskeletal proteins, the immune system and brain signalling.

Transcriptome analysis of the cerebral cortex of acrylamide-exposed wild-type and IL-1β-knockout mice

Acrylamide is an environmental electrophile that has been produced in large amounts for many years. There is concern about the adverse health effects of acrylamide exposure due to its widespread industrial use and also presence in commonly consumed foods and others. IL-1β is a key cytokine that protects the brain from inflammatory insults, but its role in acrylamide-induced neurotoxicity remains unknown. We reported recently that deletion of IL-1β gene exacerbates ACR-induced neurotoxicity in mice. The aim of this study was to identify genes or signaling pathway(s) involved in enhancement of ACR-induced neurotoxicity by IL-1β gene deletion or ACR-induced neurotoxicity to generate a hypothesis mechanism explaining ACR-induced neurotoxicity. C57BL/6 J wild-type and IL-1β KO mice were exposed to ACR at 0, 12.5, 25 mg/kg by oral gavage for 7 days/week for 4 weeks, followed by extraction of mRNA from mice cerebral cortex for RNA sequence analysis. IL-1β deletion altered the expression of genes involved in extracellular region, including upregulation of PFN1 gene related to amyotrophic lateral sclerosis and increased the expression of the opposite strand of IL-1β. Acrylamide exposure enhanced mitochondria oxidative phosphorylation, synapse and ribosome pathways, and activated various pathways of different neurodegenerative diseases, such as Alzheimer disease, Parkinson disease, Huntington disease, and prion disease. Protein network analysis suggested the involvement of different proteins in related to learning and cognitive function, such as Egr1, Egr2, Fos, Nr4a1, and Btg2. Our results identified possible pathways involved in IL-1β deletion-potentiated and ACR-induced neurotoxicity in mice.

Formation of amyloid fibrils by the regulatory 14-3-3ζ protein

The 14-3-3 proteins are a highly conserved adaptor protein family with multi-layer functions, abundantly expressed in the brain. The 14-3-3 proteins modulate phosphorylation, regulate enzymatic activity and can act as chaperones. Most importantly, they play an important role in various neurodegenerative disorders due to their vast interaction partners. Particularly, the 14-3-3ζ isoform is known to co-localize in aggregation tangles in both Alzheimer's and Parkinson's diseases as a result of protein-protein interactions. These abnormal clumps consist of amyloid fibrils, insoluble aggregates, mainly formed by the amyloid-β, tau and α-synuclein proteins. However, the molecular basis of if and how 14-3-3ζ can aggregate into amyloid fibrils is unknown. In this study, we describe the formation of amyloid fibrils by 14-3-3ζ using a comprehensive approach that combines bioinformatic tools, amyloid-specific dye binding, secondary structure analysis and atomic force microscopy. The results presented herein characterize the amyloidogenic properties of 14-3-3ζ and imply that the well-folded protein undergoes aggregation to β-sheet-rich amyloid fibrils.

CSF 14-3-3β is associated with progressive cognitive decline in Alzheimer's disease

Alzheimer's disease is a neurodegenerative disorder characterized pathologically by amyloid-beta plaques, tau tangles and neuronal loss. In clinical practice, the 14-3-3 isoform beta (β) is a biomarker that aids in the diagnosis of sporadic Creutzfeldt-Jakob disease. Recently, a proteomics study found increased CSF 14-3-3β levels in Alzheimer's disease patients, suggesting a potential link between CSF 14-3-3β and Alzheimer's disease. Our present study aimed to further investigate the role of CSF 14-3-3β in Alzheimer's disease by analysing the data of 719 participants with available CSF 14-3-3β measurements from the Alzheimer's Disease Neuroimaging Initiative. Higher CSF 14-3-3β levels were observed in the mild cognitive impairment group compared to the cognitively normal group, with the highest CSF 14-3-3β levels in the Alzheimer's disease dementia group. This study also found significant associations between CSF 14-3-3β levels and CSF biomarkers of p-tau, t-tau, pTau/Aβ42 ratios and GAP-43, as well as other Alzheimer's disease biomarkers such as Aβ-PET. An early increase in CSF 14-3-3β levels was observed prior to Aβ-PET-positive status, and CSF 14-3-3β levels continued to rise after crossing the Aβ-PET positivity threshold before reaching a plateau. The diagnostic accuracy of CSF 14-3-3β (area under the receiver operating characteristic curve = 0.819) was moderate compared to other established Alzheimer's disease biomarkers in distinguishing cognitively normal Aβ pathology-negative individuals from Alzheimer's disease Aβ pathology-positive individuals. Higher baseline CSF 14-3-3β levels were associated with accelerated cognitive decline, reduced hippocampus volumes and declining fluorodeoxyglucose-PET values over a 4-year follow-up period. Patients with mild cognitive impairment and high CSF 14-3-3β levels at baseline had a significantly increased risk [hazard ratio = 2.894 (1.599-5.238), P < 0.001] of progression to Alzheimer's disease dementia during follow-up. These findings indicate that CSF 14-3-3β may be a potential biomarker for Alzheimer's disease and could provide a more comprehensive understanding of the underlying pathological changes of Alzheimer's disease, as well as aid in the diagnosis and monitoring of disease progression.

14-3-3η Proteins as a Diagnostic Marker, Disease Activation Indicator, and Lymphoma Predictor in Patients with Primary Sjögren Syndrome

BACKGROUND

Primary Sjögren syndrome (PSS) is a chronic, autoimmune, and lymphoproliferative disease of the connective tissue. In patients with PSS, the risk of developing B-cell non-Hodgkin lymphoma (NHL) increases dramatically, with a prevalence of approximately 5%. The 14-3-3 protein isoforms are phospho-serin/phospho-threonine binding proteins associated with many malignant diseases. This study aimed to evaluate the relationship between disease activity parameters and markers predicting lymphoma development in patients with PSS and 14-3-3η proteins.

METHODS

This study was designed as an analytical case-control study. A total of 57 PSS patients and 54 healthy volunteers were included in the study. The European League Against Rheumatism (EULAR) Sjögren syndrome disease activity index (ESSDAI) was used to assess systemic disease activity in PSS. Receiver operating characteristic (ROC) analysis was used to test the diagnostic accuracy measures of the analytical results. Multivariable linear regression analysis was used to evaluate the effects of independent variables on the 14-3-3η protein.

RESULTS

The 14-3-3η protein serum levels were found to be significantly higher in PSS (2.72 [2.04-4.07]) than healthy controls (1.73 [1.41-2.43]) (P<0.0001). A significant relationship was found between 14-3-3η protein levels and ESSDAI group (β=0.385, 95%CI=0.318-1.651, P=0.005), hypocomplementemia (C3 or C4) (β=0.223, 95% CI=0.09-1.983, P=0.048) and purpura (β=0.252, 95% CI=0.335-4.903, P=0.022), which are accepted as lymphoma predictors. A significant correlation was found between PSS disease activity score ESSDAI and 14-33η protein (β=0.496, 95% CI=0.079-0.244, P=0.0002).

CONCLUSION

14-3-3η proteins are potential candidates for diagnostic marker, marker of disease activity, and predictor of lymphoma in PSS patients.

Dysregulation of extracellular vesicle protein cargo in female ME/CFS cases and sedentary controls in response to maximal exercise

In healthy individuals, physical exercise improves cardiovascular health and muscle strength, alleviates fatigue, and reduces risk of chronic diseases. Although exercise is suggested as a lifestyle intervention to manage various chronic illnesses, it negatively affects people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), who suffer from exercise intolerance. We hypothesized that altered extracellular vesicle (EV) signaling in ME/CFS patients after an exercise challenge may contribute to their prolonged and exacerbated negative response to exertion (post-exertional malaise). EVs were isolated by size exclusion chromatography from the plasma of 18 female ME/CFS patients and 17 age- and BMI-matched female sedentary controls at three time points: before, 15 minutes, and 24 hours after a maximal cardiopulmonary exercise test. EVs were characterized using nanoparticle tracking analysis and their protein cargo was quantified using Tandem Mass Tag-based (TMT) proteomics. The results show that exercise affects the EV proteome in ME/CFS patients differently than in healthy individuals and that changes in EV proteins after exercise are strongly correlated with symptom severity in ME/CFS. Differentially abundant proteins in ME/CFS patients vs. controls were involved in many pathways and systems, including coagulation processes, muscle contraction (both smooth and skeletal muscle), cytoskeletal proteins, the immune system, and brain signaling.

Regulation of Ras Signaling by S-Nitrosylation

Ras are a family of small GTPases that function as signal transduction mediators and are involved in cell proliferation, migration, differentiation and survival. The significance of Ras is further evidenced by the fact that Ras genes are among the most mutated oncogenes in different types of cancers. After translation, Ras proteins can be targets of post-translational modifications (PTM), which can alter the intracellular dynamics of the protein. In this review, we will focus on how S-nitrosylation of Ras affects the way these proteins interact with membranes, its cellular localization, and its activity. S-Nitrosylation occurs when a nitrosyl moiety of nitric oxide (NO) is covalently attached to a thiol group of a cysteine residue in a target protein. In Ras, the conserved Cys118 is the most surface-exposed Cys and the preferable residue for NO action, leading to the initiation of transduction events. Ras transduces the mitogen-activated protein kinases (MAPK), the phosphoinositide-3 kinase (PI3K) and the RalGEF cellular pathways. S-Nitrosylation of elements of the RalGEF cascade remains to be identified. On the contrary, it is well established that several components of the MAPK and PI3K pathways, as well as different proteins associated with these cascades, can be modified by S-nitrosylation. Overall, this review presents a better understanding of Ras S-nitrosylation, increasing the knowledge on the dynamics of these proteins in the presence of NO and the underlying implications in cellular signaling.

Modulating GPCR and 14-3-3 protein interactions: Prospects for CNS drug discovery

The activation of G-protein-coupled receptors (GPCRs) triggers a series of protein-protein interaction events that subsequently induce a chain of reactions, including alteration of receptor structures, phosphorylation, recruitment of associated proteins, protein trafficking and gene expression. Multiple GPCR signaling transduction pathways are evident - two well-studied pathways are the GPCR-mediated G-protein and β-arrestin pathways. Recently, ligand-induced interactions between GPCRs and 14-3-3 proteins have been demonstrated. This linking of GPCRs to 14-3-3 protein signal hubs opens up a whole new realm of signal transduction possibilities. 14-3-3 proteins play a key part in GPCR trafficking and signal transduction. GPCR-mediated 14-3-3 protein signaling can be harnessed for the study of GPCR function and therapeutics.

The Golgi Apparatus: A Voyage through Time, Structure, Function and Implication in Neurodegenerative Disorders

This comprehensive review article dives deep into the Golgi apparatus, an essential organelle in cellular biology. Beginning with its discovery during the 19th century until today's recognition as an important contributor to cell function. We explore its unique organization and structure as well as its roles in protein processing, sorting, and lipid biogenesis, which play key roles in maintaining homeostasis in cellular biology. This article further explores Golgi biogenesis, exploring its intricate processes and dynamics that contribute to its formation and function. One key focus is its role in neurodegenerative diseases like Parkinson's, where changes to the structure or function of the Golgi apparatus may lead to their onset or progression, emphasizing its key importance in neuronal health. At the same time, we examine the intriguing relationship between Golgi stress and endoplasmic reticulum (ER) stress, providing insights into their interplay as two major cellular stress response pathways. Such interdependence provides a greater understanding of cellular reactions to protein misfolding and accumulation, hallmark features of many neurodegenerative diseases. In summary, this review offers an exhaustive examination of the Golgi apparatus, from its historical background to its role in health and disease. Additionally, this examination emphasizes the necessity of further research in this field in order to develop targeted therapeutic approaches for Golgi dysfunction-associated conditions. Furthermore, its exploration is an example of scientific progress while simultaneously offering hope for developing innovative treatments for neurodegenerative disorders.

YWHAE loss of function causes a rare neurodevelopmental disease with brain abnormalities in human and mouse

PURPOSE

Miller-Dieker syndrome is caused by a multiple gene deletion, including PAFAH1B1 and YWHAE. Although deletion of PAFAH1B1 causes lissencephaly unambiguously, deletion of YWHAE alone has not clearly been linked to a human disorder.

METHODS

Cases with YWHAE variants were collected through international data sharing networks. To address the specific impact of YWHAE loss of function, we phenotyped a mouse knockout of Ywhae.

RESULTS

We report a series of 10 individuals with heterozygous loss-of-function YWHAE variants (3 single-nucleotide variants and 7 deletions <1 Mb encompassing YWHAE but not PAFAH1B1), including 8 new cases and 2 follow-ups, added with 5 cases (copy number variants) from literature review. Although, until now, only 1 intragenic deletion has been described in YWHAE, we report 4 new variants specifically in YWHAE (3 splice variants and 1 intragenic deletion). The most frequent manifestations are developmental delay, delayed speech, seizures, and brain malformations, including corpus callosum hypoplasia, delayed myelination, and ventricular dilatation. Individuals with variants affecting YWHAE alone have milder features than those with larger deletions. Neuroanatomical studies in Ywhae-/- mice revealed brain structural defects, including thin cerebral cortex, corpus callosum dysgenesis, and hydrocephalus paralleling those seen in humans.

CONCLUSION

This study further demonstrates that YWHAE loss-of-function variants cause a neurodevelopmental disease with brain abnormalities.

14-3-3ζ Plays a key role in the modulation of neuroplasticity underlying the antidepressant-like effects of Zhi-Zi-Chi-Tang

BACKGROUND

Zhi-Zi-Chi-Tang (ZZCT) is an effective traditional Chinese medicinal formula. ZZCT has been used for the treatment of depression for centuries. Its clinical efficacy in relieving depression has been confirmed. However, the molecular mechanisms of ZZCT regarding neuroplasticity in the pathogenesis of depression have not yet been elucidated.

PURPOSE

The present study aimed to examine the effects of ZZCT on neuroplasticity in mice exposed to chronic unpredictable mild stress (CUMS), and to explore the underlying molecular mechanisms.

METHODS

For this purpose, a murine model of depression was established using the CUMS procedure. Following the intragastric administration of ZZCT or fluoxetine, classic behavioral experiments were performed to observe the efficacy of ZZCT as an antidepressant. Immunofluorescence was used to label and quantify microtubule-associated protein (MAP2) and postsynaptic density protein (PSD95) in the hippocampus. Golgi staining was applied to visualize the dendritic spine density of neurons in the hippocampi. Isolated hippocampal slices were prepared to induce long-term potentiation (LTP) in the CA1 area. The hippocampal protein expression levels of glycogen synthase kinase-3β (GSK-3β), p-GSK-3β (Ser9), cAMP response element binding protein (CREB), p-CREB (Ser133), brain-derived neurotrophic factor (BDNF) and 14-3-3ζ were detected using western blot analysis. The interaction of 14-3-3ζ and p-GSK-3β (Ser9) was examined using co-immunoprecipitation. LV-shRNA was used to knockdown 14-3-3ζ by an intracerebroventricular injection.

RESULTS

ZZCT (6 g/kg) and fluoxetine (20 mg/kg) alleviated depressive-like behavior, restored hippocampal MAP2⁺ PSD95⁺ intensity, and reversed the dendritic spine density of hippocampal neurons and LTP in the CA1 region of mice exposed to CUMS. Both low and high doses of ZZCT (3 and 6 g/kg) significantly promoted the binding of 14-3-3ζ to p-GSK-3β (Ser9) in the hippocampus, and ZZCT (6 g/kg) significantly promoted the phosphorylation of GSK-3β Ser9 and CREB Ser133 in the hippocampus. ZZCT (3 and 6 g/kg) upregulated hippocampal BDNF expression in mice exposed to CUMS. LV-sh14-3-3ξ reduced the antidepressant effects of ZZCT.

CONCLUSION

ZZCT exerted antidepressant effects against CUMS-stimulated depressive-like behavior mice. The knockdown of 14-3-3ζ using lentivirus confirmed that 14-3-3ζ was involved in the ZZCT-mediated antidepressant effects through GSK-3β/CREB/BDNF signaling. On the whole, these results suggest that the antidepressant effects of ZZCT are attributed to restoring damage by neuroplasticity enhancement via the 14-3-3ζ/GSK-3β/CREB/BDNF signaling pathway.

Clinical significance of serum levels of 14-3-3β protein in patients with stable chronic obstructive pulmonary disease

Nowadays, the diagnosis and treatment of COPD are often based on the results of lung function tests. Certain individuals, however, are not candidates for lung function testing due to pulmonary bullae, cardiac failure, low lung function, and other factors. Therefore, we evaluated whether serum tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein β (14-3-3β) could be a biomarker for the diagnosis of stable COPD patients. The expression of serum 14-3-3β protein was evaluated by an enzyme-linked immunosorbent assay. The association between its concentrations and clinical parameters of stable COPD patients were analyzed by correlation analysis and ROC curve. The results before propensity score matching (PSM) showed that serum 14-3-3β protein concentrations (ng/ml) in stable COPD patients were significantly higher than in healthy controls (P < 0.001). Furthermore, serum 14-3-3β protein concentrations were higher in GOLD 3&4 COPD patients compared with healthy participants, GOLD 1 and GOLD 2 COPD patients (P < 0.05), which shows that the concentration of 14-3-3β protein correlates with disease severity in stable COPD patients. After 1:1 PSM, there was also a statistically significant rise in 14-3-3 protein levels in stable COPD patients compared to healthy controls (P < 0.01). Serum 14-3-3β protein levels were positively correlated with blood neutrophil levels (P < 0.05), and negatively related to lung function parameters in stable COPD patients (P < 0.01). When the cutoff value was set at 29.53 ng/ml, the ROC curve yielded a sensitivity of 84.9% and a specificity of 68.3% for diagnosing stable COPD. The 14-3-3β protein may be a potential serum biomarker for the diagnosis of stable COPD patients, which is associated with disease severity, systemic inflammation, and small airway obstruction.

Identification of YWHAH as a Novel Brain-Derived Extracellular Vesicle Marker Post Long-Term Midazolam Exposure during Early Development

Recently, the long-term use of sedative agents in the neonatal intensive care unit (NICU) has raised concerns about neurodevelopmental outcomes in exposed neonates. Midazolam (MDZ), a common neonatal sedative in the NICU, has been suggested to increase learning disturbances and cognitive impairment in children. However, molecular mechanisms contributing to such outcomes with long-term MDZ use during the early stages of life remain unclear. In this study, we for the first time elucidate the role of brain-derived extracellular vesicles (BDEVs), including mining the BDEV proteome post long-term MDZ exposure during early development. Employing our previously established rodent model system that mimics the exposure of MDZ in the NICU using an increasing dosage regimen, we isolated BDEVs from postnatal 21-days-old control and MDZ groups using a differential sucrose density gradient. BDEVs from the control and MDZ groups were then characterized using a ZetaView nanoparticle tracking analyzer and transmission electron microscopy analysis. Next, using RT-qPCR, we examined the expression of key ESCRT-related genes involved in EV biogenesis. Lastly, using quantitative mass spectrometry-based proteomics, we mined the BDEV protein cargo that revealed key differentially expressed proteins and associated molecular pathways to be altered post long-term MDZ exposure. Our study characterized the proteome in BDEV cargo from long-term MDZ exposure at early development. Importantly, we identified and validated the expression of YWHAH as a potential target for further characterization of its downstream mechanism and a potential biomarker for the early onset of neurodevelopment and neurodegenerative diseases. Overall, the present study demonstrated long-term exposure to MDZ at early development stages could influence BDEV protein cargo, which potentially impact neural functions and behavior at later stages of development.

14-3-3ζ Mediates GABAAR Activation by Interacting with BIG1

Most fast synaptic inhibitions in the mammalian brain are mediated by GABA_A receptors (GABA_ARs). An appropriate level of GABA_AR expression at the cell surface is essential for neurodevelopment and the efficacy of GABAergic synaptic transmission. We previously reported that brefeldin A-inhibited GDP/GTP exchange factor 1 (BIG1), a binding partner of GABA_ARs, plays an important role in trafficking GABA_ARs to the cell surface. However, its regulatory mechanisms remain unknown. In the present study, we identified a new cellular protein, 14-3-3ζ, which can interact with the β subunit of GABA_ARs and BIG1 both in vitro and in vivo and colocalizes in the soma, dendrites, and axons of hippocampal neurons. Overexpression of 14-3-3ζ-WT increased the surface expression of BIG1 in dendrites and axons, as well as the binding of BIG1 with GABA_AR. Depleted 14-3-3ζ with efficacious siRNA attenuated the interaction between BIG1 and GABA_ARs and resulted in significant decreases in the surface expression levels of BIG1 and GABA_AR. GABA_AR agonist treatment increased the expression levels of BIG1 and 14-3-3ζ on the surface, indicating that 14-3-3ζ is involved in regulating BIG1-mediated GABA_AR surface expression. Depletion of BIG1 or 14-3-3ζ significantly decreased GABA_AR expression at the cell surface and suppressed the GABA-gated influx of chloride ions. These data indicate that the combination of 14-3-3ζ and BIG1 is required for GABA_AR membrane expression. Our results provide a potential promising therapeutic target for neurological disorders involving GABAergic synaptic transmission.

Proteomic analysis for the effects of non-saponin fraction with rich polysaccharide from Korean Red Ginseng on Alzheimer's disease in a mouse model

Background

The most common type of dementia, Alzheimer's disease (AD), is marked by the formation of extracellular amyloid beta (Aβ) plaques. The impairments of axons and synapses appear in the process of Aβ plaques formation, and this damage could cause neurodegeneration. We previously reported that non-saponin fraction with rich polysaccharide (NFP) from Korean Red Ginseng (KRG) showed neuroprotective effects in AD. However, precise molecular mechanism of the therapeutic effects of NFP from KRG in AD still remains elusive.

Methods

To investigate the therapeutic mechanisms of NFP from KRG on AD, we conducted proteomic analysis for frontal cortex from vehicle-treated wild-type, vehicle-treated 5XFAD mice, and NFP-treated 5XFAD mice by using nano-LC-ESI-MS/MS. Metabolic network analysis was additionally performed as the effects of NFP appeared to be associated with metabolism according to the proteome analysis.

Results

Starting from 5,470 proteins, 2,636 proteins were selected for hierarchical clustering analysis, and finally 111 proteins were further selected for protein-protein interaction network analysis. A series of these analyses revealed that proteins associated with synapse and mitochondria might be linked to the therapeutic mechanism of NFP. Subsequent metabolic network analysis via genome-scale metabolic models that represent the three mouse groups showed that there were significant changes in metabolic fluxes of mitochondrial carnitine shuttle pathway and mitochondrial beta-oxidation of polyunsaturated fatty acids.

Conclusion

Our results suggested that the therapeutic effects of NFP on AD were associated with synaptic- and mitochondrial-related pathways, and they provided targets for further rigorous studies on precise understanding of the molecular mechanism of NFP.

Transcriptomic profiles of stress susceptibility and resilience in the amygdala and hippocampus

A single, severe episode of stress can bring about myriad responses amongst individuals, ranging from cognitive enhancement to debilitating and persistent anxiety; however, the biological mechanisms that contribute to resilience versus susceptibility to stress are poorly understood. The dentate gyrus (DG) of the hippocampus and the basolateral nucleus of the amygdala (BLA) are key limbic regions that are susceptible to the neural and hormonal effects of stress. Previous work has also shown that these regions contribute to individual variability in stress responses; however, the molecular mechanisms underlying the role of these regions in susceptibility and resilience are unknown. In this study, we profiled the transcriptomic signatures of the DG and BLA of rats with divergent behavioral outcomes after a single, severe stressor. We subjected rats to three hours of immobilization with exposure to fox urine and conducted a behavioral battery one week after stress to identify animals that showed persistent, high anxiety-like behavior. We then conducted bulk RNA sequencing of the DG and BLA from susceptible, resilient, and unexposed control rats. Differential gene expression analyses revealed that the molecular signatures separating each of the three groups were distinct and non-overlapping between the DG and BLA. In the amygdala, key genes associated with insulin and hormonal signaling corresponded with vulnerability. Specifically, Inhbb, Rab31 , and Ncoa3 were upregulated in the amygdala of stress-susceptible animals compared to resilient animals. In the hippocampus, increased expression of Cartpt - which encodes a key neuropeptide involved in reward, reinforcement, and stress responses - was strongly correlated with vulnerability to anxiety-like behavior. However, few other genes distinguished stress-susceptible animals from control animals, while a larger number of genes separated stress-resilient animals from control and stress-susceptible animals. Of these, Rnf112, Tbx19 , and UBALD1 distinguished resilient animals from both control and susceptible animals and were downregulated in resilience, suggesting that an active molecular response in the hippocampus facilitates protection from the long-term consequences of severe stress. These results provide novel insight into the mechanisms that bring about individual variability in the behavioral responses to stress and provide new targets for the advancement of therapies for stress-induced neuropsychiatric disorders.

14-3-3 proteins regulate cullin 7-mediated Eag1 degradation

BACKGROUND

Mutations in the human gene encoding the neuron-specific Eag1 (K_V10.1; KCNH1) potassium channel are linked to congenital neurodevelopmental diseases. Disease-causing mutant Eag1 channels manifest aberrant gating function and defective protein homeostasis. Both the E3 ubiquitin ligase cullin 7 (Cul7) and the small acid protein 14-3-3 serve as binding partners of Eag1. Cul7 mediates proteasomal and lysosomal degradation of Eag1 protein, whereas over-expression of 14-3-3 notably reduces Eag1 channel activity. It remains unclear whether 14-3-3 may also contribute to Eag1 protein homeostasis.

RESULTS

In human cell line and native rat neurons, disruptions of endogenous 14-3-3 function with the peptide inhibitor difopein or specific RNA interference up-regulated Eag1 protein level in a transcription-independent manner. Difopein hindered Eag1 protein ubiquitination at the endoplasmic reticulum and the plasma membrane, effectively promoting the stability of both immature and mature Eag1 proteins. Suppression of endogenous 14-3-3 function also reduced excitotoxicity-associated Eag1 degradation in neurons. Difopein diminished Cul7-mediated Eag1 degradation, and Cul7 knock-down abolished the effect of difopein on Eag1. Inhibition of endogenous 14-3-3 function substantially perturbed the interaction of Eag1 with Cul7. Further structural analyses suggested that the intracellular Per-Arnt-Sim (PAS) domain and cyclic nucleotide-binding homology domain (CNBHD) of Eag1 are essential for the regulatory effect of 14-3-3 proteins. Significantly, suppression of endogenous 14-3-3 function reduced Cul7-mediated degradation of disease-associated Eag1 mutant proteins.

CONCLUSION

Overall these results highlight a chaperone-like role of endogenous 14-3-3 proteins in regulating Eag1 protein homeostasis, as well as a therapeutic potential of 14-3-3 modulators in correcting defective protein expression of disease-causing Eag1 mutants.

14-3-3γ haploinsufficiency leads to altered dopamine pathway and Parkinson's disease-like motor incoordination in mice

The 14-3-3 protein family with seven isoforms found in mammals is widely expressed in the brain and plays various roles in cellular processes. Several studies have reported that 14-3-3γ, one of the 14-3-3 protein isoforms, is associated with neurological and psychiatric disorders, but the role of 14-3-3γ in the pathophysiology of brain diseases is unclear. Although studies have been conducted on the relationship between 14-3-3γ protein and Parkinson's disease (PD), a common neurodegenerative disorder with severe motor symptoms such as bradykinesia and rigidity, a direct connection remains to be elucidated. We recently showed that adult heterozygous 14-3-3γ knockout mice are hyperactive and exhibit anxiety-like behavior. In this study, we further characterized the molecular and behavioral changes in aged 14-3-3γ heterozygous mice to investigate the role of 14-3-3γ in the brain. We observed decreased dopamine levels and altered dopamine metabolism in the brains of these mice, including changes in the phosphorylation of proteins implicated in PD pathology. Furthermore, we confirmed that they displayed PD symptom-like behavioral deficits, such as impaired motor coordination and decreased ability to the nest-building activity. These findings suggest an association between 14-3-3γ dysfunction and PD pathophysiology.

Patterns and Persistence of Perioperative Plasma and Cerebrospinal Fluid Neuroinflammatory Protein Biomarkers After Elective Orthopedic Surgery Using SOMAscan

BACKGROUND

The neuroinflammatory response to surgery can be characterized by peripheral acute plasma protein changes in blood, but corresponding, persisting alterations in cerebrospinal fluid (CSF) proteins remain mostly unknown. Using the SOMAscan assay, we define acute and longer-term proteome changes associated with surgery in plasma and CSF. We hypothesized that biological pathways identified by these proteins would be in the categories of neuroinflammation and neuronal function and define neuroinflammatory proteome changes associated with surgery in older patients.

METHODS

SOMAscan analyzed 1305 proteins in blood plasma (n = 14) and CSF (n = 15) samples from older patients enrolled in the Role of Inflammation after Surgery for Elders (RISE) study undergoing elective hip and knee replacement surgery with spinal anesthesia. Systems biology analysis identified biological pathways enriched among the surgery-associated differentially expressed proteins in plasma and CSF.

RESULTS

Comparison of postoperative day 1 (POD1) to preoperative (PREOP) plasma protein levels identified 343 proteins with postsurgical changes ( P < .05; absolute value of the fold change [|FC|] > 1.2). Comparing postoperative 1-month (PO1MO) plasma and CSF with PREOP identified 67 proteins in plasma and 79 proteins in CSF with altered levels ( P < .05; |FC| > 1.2). In plasma, 21 proteins, primarily linked to immune response and inflammation, were similarly changed at POD1 and PO1MO. Comparison of plasma to CSF at PO1MO identified 8 shared proteins. Comparison of plasma at POD1 to CSF at PO1MO identified a larger number, 15 proteins in common, most of which are regulated by interleukin-6 (IL-6) or transforming growth factor beta-1 (TGFB1) and linked to the inflammatory response. Of the 79 CSF PO1MO-specific proteins, many are involved in neuronal function and neuroinflammation.

CONCLUSIONS

SOMAscan can characterize both short- and long-term surgery-induced protein alterations in plasma and CSF. Acute plasma protein changes at POD1 parallel changes in PO1MO CSF and suggest 15 potential biomarkers for longer-term neuroinflammation that warrant further investigation.

The function of Golgi apparatus in LRRK2-associated Parkinson's disease

Parkinson's disease (PD) is a chronic neurodegenerative disease associated with the intracellular organelles. Leucine-rich repeat kinase 2 (LRRK2) is a large multi-structural domain protein, and mutation in LRRK2 is associated with PD. LRRK2 regulates intracellular vesicle transport and function of organelles, including Golgi and lysosome. LRRK2 phosphorylates a group of Rab GTPases, including Rab29, Rab8, and Rab10. Rab29 acts in a common pathway with LRRK2. Rab29 has been shown to recruit LRRK2 to the Golgi complex (GC) to stimulate LRRK2 activity and alter the Golgi apparatus (GA). Interaction between LRRK2 and Vacuolar protein sorting protein 52 (VPS52), a subunit of the Golgi-associated retrograde protein (GARP) complex, mediates the function of intracellular soma trans-Golgi network (TGN) transport. VPS52 also interacts with Rab29. Knockdown of VPS52 leads to the loss of LRRK2/Rab29 transported to the TGN. Rab29, LRRK2, and VPS52 work together to regulate functions of the GA, which is associated with PD. We highlight recent advances in the roles of LRRK2, Rabs, VPS52, and other molecules, such as Cyclin-dependent kinase 5 (CDK5) and protein kinase C (PKC) in the GA, and discuss their possible association with the pathological mechanisms of PD.

Systematic Review of Clinical and Pathophysiological Features of Genetic Creutzfeldt-Jakob Disease Caused by a Val-to-Ile Mutation at Codon 180 in the Prion Protein Gene

Genetic Creutzfeldt-Jakob disease (gCJD) is a subtype of genetic prion diseases (gPrDs) caused by the accumulation of mutated pathological prion proteins (PrPSc). gCJD has a phenotypic similarity with sporadic CJD (sCJD). In Japan, gCJD with a Val to Ile substitution at codon 180 (V180I-gCJD) is the most frequent gPrD, while the mutation is extremely rare in countries other than Japan and Korea. In this article, we aim to review previously elucidated clinical and biochemical features of V180I-gCJD, expecting to advance the understanding of this unique subtype in gCJD. Compared to classical sCJD, specific clinical features of V180I-gCJD include older age at onset, a relatively slow progression of dementia, and a lower positivity for developing myoclonus, cerebellar, pyramidal signs, and visual disturbance. Diffuse edematous ribboning hyperintensity of the cerebral cortex, without occipital lobes in diffusion-weighted magnetic resonance imaging, is also specific. Laboratory data reveal the low positivity of PrPSc in the cerebrospinal fluid and periodic sharp wave complexes on an electroencephalogram. Most patients with V180I-gCJD have been reported to have no family history, probably due to the older age at onset, and clinical and biochemical features indicate the specific phenotype associated with the prion protein gene mutation.

Proteomic Identification of Phosphorylation-Dependent Septin 7 Interactors that Drive Dendritic Spine Formation

Septins are a family of cytoskeletal proteins that regulate several important aspects of neuronal development. Septin 7 (Sept7) is enriched at the base of dendritic spines in excitatory neurons and mediates both spine formation and spine and synapse maturation. Phosphorylation at a conserved C-terminal tail residue of Sept7 mediates its translocation into the dendritic spine head to allow spine and synapse maturation. The mechanistic basis for postsynaptic stability and compartmentalization conferred by phosphorylated Sept7, however, is unclear. We report herein the proteomic identification of Sept7 phosphorylation-dependent neuronal interactors. Using Sept7 C-terminal phosphopeptide pulldown and biochemical assays, we show that the 14-3-3 family of proteins specifically interacts with Sept7 when phosphorylated at the T426 residue. Biochemically, we validate the interaction between Sept7 and 14-3-3 isoform gamma and show that 14-3-3 gamma is also enriched in the mature dendritic spine head. Furthermore, we demonstrate that interaction of phosphorylated Sept7 with 14-3-3 protects it from dephosphorylation, as expression of a 14-3-3 antagonist significantly decreases phosphorylated Sept7 in neurons. This study identifies 14-3-3 proteins as an important physiological regulator of Sept7 function in neuronal development.

Clearance of an amyloid-like translational repressor is governed by 14-3-3 proteins

Amyloids are fibrous protein aggregates associated with age-related diseases. While these aggregates are typically described as irreversible and pathogenic, some cells use reversible amyloid-like structures that serve important functions. The RNA-binding protein Rim4 forms amyloid-like assemblies that are essential for translational control during Saccharomyces cerevisiae meiosis. Rim4 amyloid-like assemblies are disassembled in a phosphorylation-dependent manner at meiosis II onset. By investigating Rim4 clearance, we elucidate co-factors that mediate clearance of amyloid-like assemblies in a physiological setting. We demonstrate that yeast 14-3-3 proteins bind to Rim4 assemblies and facilitate their subsequent phosphorylation and timely clearance. Furthermore, distinct 14-3-3 proteins play non-redundant roles in facilitating phosphorylation and clearance of amyloid-like Rim4. Additionally, we find that 14-3-3 proteins contribute to global protein aggregate homeostasis. Based on the role of 14-3-3 proteins in aggregate homeostasis and their interactions with disease-associated assemblies, we propose that these proteins may protect against pathological protein aggregates.

ADRAM is an experience-dependent long noncoding RNA that drives fear extinction through a direct interaction with the chaperone protein 14-3-3

Here, we used RNA capture-seq to identify a large population of lncRNAs that are expressed in the infralimbic prefrontal cortex of adult male mice in response to fear-related learning. Combining these data with cell-type-specific ATAC-seq on neurons that had been selectively activated by fear extinction learning, we find inducible 434 lncRNAs that are derived from enhancer regions in the vicinity of protein-coding genes. In particular, we discover an experience-induced lncRNA we call ADRAM (activity-dependent lncRNA associated with memory) that acts as both a scaffold and a combinatorial guide to recruit the brain-enriched chaperone protein 14-3-3 to the promoter of the memory-associated immediate-early gene Nr4a2 and is required fear extinction memory. This study expands the lexicon of experience-dependent lncRNA activity in the brain and highlights enhancer-derived RNAs (eRNAs) as key players in the epigenomic regulation of gene expression associated with the formation of fear extinction memory.

The 14-3-3 Protein Family and Schizophrenia

Schizophrenia is a debilitating mental disorder that affects approximately 1% of the world population, yet the disorder is not very well understood. The genetics of schizophrenia is very heterogenous, making it hard to pinpoint specific alterations that may cause the disorder. However, there is growing evidence from human studies suggesting a link between alterations in the 14-3-3 family and schizophrenia. The 14-3-3 proteins are abundantly expressed in the brain and are involved in many important cellular processes. Knockout of 14-3-3 proteins in mice has been shown to cause molecular, structural, and behavioral alterations associated with schizophrenia. Thus, 14-3-3 animal models allow for further exploration of the relationship between 14-3-3 and schizophrenia as well as the study of schizophrenia pathology. This review considers evidence from both human and animal model studies that implicate the 14-3-3 family in schizophrenia. In addition, possible mechanisms by which alterations in 14-3-3 proteins may contribute to schizophrenia-like phenotypes such as dopaminergic, glutamatergic, and cytoskeletal dysregulations are discussed.

14-3-3 proteins at the crossroads of neurodevelopment and schizophrenia

The 14-3-3 family comprises multifunctional proteins that play a role in neurogenesis, neuronal migration, neuronal differentiation, synaptogenesis and dopamine synthesis. 14-3-3 members function as adaptor proteins and impact a wide variety of cellular and physiological processes involved in the pathophysiology of neurological disorders. Schizophrenia is a psychiatric disorder and knowledge about its pathophysiology is still limited. 14-3-3 have been proven to be linked with the dopaminergic, glutamatergic and neurodevelopmental hypotheses of schizophrenia. Further, research using genetic models has demonstrated the role played by 14-3-3 proteins in neurodevelopment and neuronal circuits, however a more integrative and comprehensive approach is needed for a better understanding of their role in schizophrenia. For instance, we still lack an integrated assessment of the processes affected by 14-3-3 proteins in the dopaminergic and glutamatergic systems. In this context, it is also paramount to understand their involvement in the biology of brain cells other than neurons. Here, we present previous and recent research that has led to our current understanding of the roles 14-3-3 proteins play in brain development and schizophrenia, perform an assessment of their functional protein association network and discuss the use of protein-protein interaction modulators to target 14-3-3 as a potential therapeutic strategy.

14-3-3 protein regulation of excitation-contraction coupling

14-3-3 proteins (14-3-3 s) are a family of highly conserved proteins that regulate many cellular processes in eukaryotes by interacting with a diverse array of client proteins. The 14-3-3 proteins have been implicated in several disease states and previous reviews have condensed the literature with respect to their structure, function, and the regulation of different cellular processes. This review focuses on the growing body of literature exploring the important role 14-3-3 proteins appear to play in regulating the biochemical and biophysical events associated with excitation-contraction coupling (ECC) in muscle. It presents both a timely and unique analysis that seeks to unite studies emphasizing the identification and diversity of 14-3-3 protein function and client protein interactions, as modulators of muscle contraction. It also highlights ideas within these two well-established but intersecting fields that support further investigation with respect to the mechanistic actions of 14-3-3 proteins in the modulation of force generation in muscle.

Potential Serum Biomarkers for Postoperative Neurocognitive Disorders Based on Proteomic Analysis of Cognitive-Related Brain Regions

Postoperative neurocognitive disorders (po-NCD), including postoperative delirium (POD) and delayed neurocognitive recovery (dNCR), are common in geriatric surgical patients. However, the ideal diagnostic biomarkers to predict individual risks of po-NCDs have not been identified. In this study, proteomic analysis was used to detect dysregulated proteins in three cognitive-related brain regions, the hippocampus, prefrontal cortex, and temporal lobe, of aged dNCR rats. The common affected proteins in these three brain regions were further verified by real-time polymerase chain reaction and western blotting. Furthermore, serum samples from aged rats with dNCR and elderly hip fracture patients with POD were also assessed with enzyme linked immunosorbent assays to investigate the biomarker potential of these dysregulated proteins. The increased expression levels of haptoglobin, caseinolytic protease (ClpP), and alpha-2 macroglobulin (A2M) as well as decreased expression levels of 14-3-3β/α and biliverdin reductase-A (BVR-A) were validated by proteomic analysis in the hippocampus, prefrontal cortex, and temporal lobe of aged dNCR rats. The increased expression of haptoglobin and decreased expression of 14-3-3β/α were further demonstrated in the three brain regions by western blotting. Moreover, increased levels of S100A6 and BVR-A in the hippocampus, S100A6 in the prefrontal cortex, and A2M in the temporal lobe were also observed. More intriguingly, both decreased serum 14-3-3β/α and increased A2M in geriatric POD patients as well as decreased serum ClpP in aged dNCR rats were verified. These results not only indicate potential diagnostic biomarkers for po-NCD but also provide directions for further pathological investigations.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier [ChiCTR1900027393].

Serum 14-3-3β protein: a new biomarker in asthmatic patients with acute exacerbation in an observational study

Background

The determination of systemic inflammatory markers is one of the important directions to study the pathogenesis of asthma and improve the diagnosis of asthma. Current studies have found that the 14-3-3 protein family subtypes interact with target proteins to participate in the pathogenesis of a variety of immune inflammatory diseases. However, studies on serum tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein β (14-3-3β) in asthma are scarce. This study aimed to assess the clinical significance of 14-3-3β in asthmatic patients.

Methods

We recruited 54 asthmatic patients with acute exacerbation and 50 asthmatic patients with chronic persistent. The normal control group included 54 healthy individuals. Clinical characteristics, clinical indicators [fractional expiratory nitric oxide (FeNO), eosinophil count, forced vital capacity (FVC), percent of predicted FVC (FVC% predicted), forced expiratory volume in one second (FEV1), percent of predicted FEV1 (FEV1% predicted), the ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) and serum 14-3-3β levels were measured to compare among each group. Spearman’s rank correlation coefficient was used to evaluate the correlation between 14-3-3β and clinical indicators. Finally, Receiver-operating characteristic (ROC) curves analysis was used to determine the sensitivity and specificity of 14-3-3β.

Results

Our results showed that median (interquartile range) of serum 14-3-3β concentration (ng/mL) in acute exacerbation group of asthma (41.18 [33.06–51.76]) was much higher than that in normal control group (24.99 [17.43–29.91]; P < 0.001) and chronic persistent group of asthma (25.88 [21.03–34.55]; P < 0.001). Spearman’s correlation coefficient shows that the serum 14-3-3β level was positively correlated with FeNO (r = − 0.292, P = 0.032) and peripheral blood eosinophil count (r = 0.328, P = 0.016), and was negatively related to FEV1/FVC (r = − 0.293, P = 0.031) in the acute exacerbation group of asthma. At the same time, the serum 14-3-3β level was also negatively associated with FEV1 (r = − 0.297, P = 0.036) in the chronic persistent group of asthma. ROC curve analysis comparing acute exacerbation group of asthma with normal control group demonstrated a significant (P < 0.001) AUC of 0.90 (95% CI 0.85–0.96).

Conclusion

The serum 14-3-3β protein may become a potential biomarker in asthmatic patients with acute exacerbation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-021-00608-4.

Differential barcoding of opioid receptors trafficking

Over the past several years, studies have highlighted the δ-opioid receptor (DOPr) as a promising therapeutic target for chronic pain management. While exhibiting milder undesired effects than most currently prescribed opioids, its specific agonists elicit effective analgesic responses in numerous animal models of chronic pain, including inflammatory, neuropathic, diabetic, and cancer-related pain. However, as compared with the extensively studied μ-opioid receptor, the molecular mechanisms governing its trafficking remain elusive. Recent advances have denoted several significant particularities in the regulation of DOPr intracellular routing, setting it apart from the other members of the opioid receptor family. Although they share high homology, each opioid receptor subtype displays specific amino acid patterns potentially involved in the regulation of its trafficking. These precise motifs or "barcodes" are selectively recognized by regulatory proteins and therefore dictate several aspects of the itinerary of a receptor, including its anterograde transport, internalization, recycling, and degradation. With a specific focus on the regulation of DOPr trafficking, this review will discuss previously reported, as well as potential novel trafficking barcodes within the opioid and nociceptin/orphanin FQ opioid peptide receptors, and their impact in determining distinct interactomes and physiological responses.

Pathways to Parkinson's disease: a spotlight on 14-3-3 proteins

14-3-3s represent a family of highly conserved 30 kDa acidic proteins. 14-3-3s recognize and bind specific phospho-sequences on client partners and operate as molecular hubs to regulate their activity, localization, folding, degradation, and protein-protein interactions. 14-3-3s are also associated with the pathogenesis of several diseases, among which Parkinson's disease (PD). 14-3-3s are found within Lewy bodies (LBs) in PD patients, and their neuroprotective effects have been demonstrated in several animal models of PD. Notably, 14-3-3s interact with some of the major proteins known to be involved in the pathogenesis of PD. Here we first provide a detailed overview of the molecular composition and structural features of 14-3-3s, laying significant emphasis on their peculiar target-binding mechanisms. We then briefly describe the implication of 14-3-3s in the central nervous system and focus on their interaction with LRRK2, α-Synuclein, and Parkin, three of the major players in PD onset and progression. We finally discuss how different types of small molecules may interfere with 14-3-3s interactome, thus representing a valid strategy in the future of drug discovery.

A Structural Study of the Cytoplasmic Chaperone Effect of 14-3-3 Proteins on Ataxin-1

Expansion of the polyglutamine tract in the N terminus of Ataxin-1 is the main cause of the neurodegenerative disease, spinocerebellar ataxia type 1 (SCA1). However, the C-terminal part of the protein - including its AXH domain and a phosphorylation on residue serine 776 - also plays a crucial role in disease development. This phosphorylation event is known to be crucial for the interaction of Ataxin-1 with the 14-3-3 adaptor proteins and has been shown to indirectly contribute to Ataxin-1 stability. Here we show that 14-3-3 also has a direct anti-aggregation or "chaperone" effect on Ataxin-1. Furthermore, we provide structural and biophysical information revealing how phosphorylated S776 in the intrinsically disordered C terminus of Ataxin-1 mediates the cytoplasmic interaction with 14-3-3 proteins. Based on these findings, we propose that 14-3-3 exerts the observed chaperone effect by interfering with Ataxin-1 dimerization through its AXH domain, reducing further self-association. The chaperone effect is particularly important in the context of SCA1, as it was previously shown that a soluble form of mutant Ataxin-1 is the major driver of pathology.

Label-Free Quantitative Proteome Profiling of Cerebrospinal Fluid from a Rat Stroke Model with Stem Cell Therapy

Human adipose-derived mesenchymal stem cells (hAMSCs) are capable of immunomodulation and regeneration after neural injury. For these reasons, hAMSCs have been investigated as a promising stem cell candidate for stroke treatment. However, noninvasive experiments studying the effects of grafted stem cells in the host brain have not yet been reported. Cerebrospinal fluid (CSF), which can be collected without sacrificing the subject, is involved in physiological control of the brain and reflects the pathophysiology of various neurological disorders of the central nervous system (CNS). Following stem cell transplantation in a stroke model, quantitative analysis of CSF proteome changes can potentially reveal the therapeutic effect of stem cells on the host CNS. We examined hAMSC-secreted proteins obtained from serum-free culture medium by liquid chromatography-tandem mass spectrometry (LC-MS/MS), which identified several extracellular matrix proteins, supporting the well-known active paracrine function of hAMSCs. Subsequently, we performed label-free quantitative proteomic analysis on CSF samples from rat stroke models intravenously injected with hAMSC (experimental) or phosphate buffered saline (control). In total, 524 proteins were identified; among them, 125 and 91 proteins were increased and decreased with hAMSC treatment, respectively. Furthermore, gene set enrichment analysis revealed three proteins, 14-3-3 theta, MAG, and neurocan, that showed significant increases in the hAMSC-treated model; these proteins are core members of neurotrophin signaling, nerve growth factor (NGF) signaling, and glycosaminoglycan metabolism, respectively. Subsequent histological and neurologic function experiments validated proliferative neurogenesis in the hAMSC-treated stroke model. We conclude that (i) intravenous injection of hAMSCs can induce neurologic recovery in a rat stroke model and (ii) CSF may reflect the therapeutic effect of hAMSCs. Additionally, proteins as 14-3-3 theta, MAG, and neurocan could be considered as potential CSF biomarkers of neuroregeneration. These CSF proteome profiling results would be utilized as valuable resource in further stroke studies.

IRE1α RIDD activity induced under ER stress drives neuronal death by the degradation of 14-3-3 θ mRNA in cortical neurons during glucose deprivation

Altered protein homeostasis is associated with neurodegenerative diseases and acute brain injury induced under energy depletion conditions such as ischemia. The accumulation of damaged or unfolded proteins triggers the unfolded protein response (UPR), which can act as a homeostatic response or lead to cell death. However, the factors involved in turning and adaptive response into a cell death mechanism are still not well understood. Several mechanisms leading to brain injury induced by severe hypoglycemia have been described but the contribution of the UPR has been poorly studied. Cell responses triggered during both the hypoglycemia and the glucose reinfusion periods can contribute to neuronal death. Therefore, we have investigated the activation dynamics of the PERK and the IRE1α branches of the UPR and their contribution to neuronal death in a model of glucose deprivation (GD) and glucose reintroduction (GR) in cortical neurons. Results show a rapid activation of the PERK/p-eIF2α/ATF4 pathway leading to protein synthesis inhibition during GD, which contributes to neuronal adaptation, however, sustained blockade of protein synthesis during GR promotes neuronal death. On the other hand, IRE1α activation occurs early during GD due to its interaction with BAK/BAX, while ASK1 is recruited to IRE1α activation complex during GR promoting the nuclear translocation of JNK and the upregulation of Chop. Most importantly, results show that IRE1α RNase activity towards its splicing target Xbp1 mRNA occurs late after GR, precluding a homeostatic role. Instead, IRE1α activity during GR drives neuronal death by positively regulating ASK1/JNK activity through the degradation of 14-3-3 θ mRNA, a negative regulator of ASK and an adaptor protein highly expressed in brain, implicated in neuroprotection. Collectively, results describe a novel regulatory mechanism of cell death in neurons, triggered by the downregulation of 14-3-3 θ mRNA induced by the IRE1α branch of the UPR.

Emerging Brain-Pathophysiology-Mimetic Platforms for Studying Neurodegenerative Diseases: Brain Organoids and Brains-on-a-Chip

Neurodegenerative diseases are a group of disorders characterized by progressive degeneration of the structural and functional integrity of the central and peripheral nervous systems. Millions of people suffer from degenerative brain diseases worldwide, and the mortality continues to increase every year, causing a growing demand for knowledge of the underlying mechanisms and development of therapeutic targets. Conventional 2D-based cell culture platforms and animal models cannot fully recapitulate the pathophysiology, and this has limited the capability for estimating drug efficacy. Recently, engineered platforms, including brain organoids and brain-on-a-chip, have emerged. They mimic the physiology of brain tissue and reflect the fundamental pathophysiological signatures of neurodegenerative diseases, such as the accumulation of neurotoxic proteins, structural abnormalities, and functional loss. In this paper, recent advances in brain-mimetic platforms and their potential for modeling features of neurodegenerative diseases in vitro are reviewed. The development of a physiologically relevant model should help overcome unresolved neurodegenerative diseases.

Illumination of Molecular Pathways in Multiple Sclerosis Lesions and the Immune Mechanism of Matrine Treatment in EAE, a Mouse Model of MS

The etiology of multiple sclerosis (MS) is not clear, and the treatment of MS presents a great challenge. This study aimed to investigate the pathogenesis and potential therapeutic targets of MS and to define target genes of matrine, a quinolizidine alkaloid component derived from the root of Sophorae flavescens that effectively suppressed experimental autoimmune encephalomyelitis (EAE), an animal model of MS. To this end, the GSE108000 gene data set in the Gene Expression Omnibus Database, which included 7 chronic active MS lesions and 10 control samples of white matter, was analyzed for differentially expressed genes (DEGs). X cell was used to analyze the microenvironmental differences in brain tissue samples of MS patients, including 64 types of immune cells and stromal cells. The biological functions and enriched signaling pathways of DEGs were analyzed by multiple approaches, including GO, KEGG, GSEA, and GSVA. The results by X cell showed significantly increased numbers of immune cell populations in the MS lesions, with decreased erythrocytes, megakaryocytes, adipocytes, keratinocytes, endothelial cells, Th1 cells and Tregs. In GSE108000, there were 637 DEGs, including 428 up-regulated and 209 down-regulated genes. Potential target genes of matrine were then predicted by the network pharmacology method of Traditional Chinese medicine, and 12 key genes were obtained by cross analysis of the target genes of matrine and DEGs in MS lesions. Finally, we confirmed by RT-PCR the predicted expression of these genes in brain tissues of matrine-treated EAE mice. Among these genes, 2 were significantly downregulated and 6 upregulated by matrine treatment, and the significance of this gene regulation was further investigated. In conclusion, our study defined several possible matrine target genes, which can be further elucidated as mechanism(s) of matrine action, and novel targets in the treatment of MS.

Inhibition of 14-3-3 Proteins Alters Neural Oscillations in Mice

Accumulating evidence suggests that schizophrenia is a disorder of the brain’s communication, a result of functional and structural dysconnectivities. Patients with schizophrenia exhibit irregular neuronal circuit and network activity, but the causes and consequences of such activity remain largely unknown. Inhibition of 14-3-3 proteins in the mouse brain leads to the expression of multiple schizophrenia endophenotypes. Here we investigated how 14-3-3 inhibition alters neuronal network activity in the mouse hippocampus (HPC) and prefrontal cortex (PFC), key brain regions implicated in schizophrenia pathophysiology. We implanted monopolar recording electrodes in these two regions to record local field potentials both at rest and during a cognitive task. Through our assessment of band power, coherence, and phase-amplitude coupling, we found that neural oscillations in the theta and gamma frequency ranges were altered as a result of 14-3-3 dysfunction. Utilizing transgenic and viral mouse models to assess the effects of chronic and acute 14-3-3 inhibition on oscillatory activities, respectively, we observed several fundamental similarities and differences between the two models. We localized viral mediated 14-3-3 protein inhibition to either the HPC or PFC, allowing us to assess the individual contributions of each region to the observed changes in neural oscillations. These findings identify a novel role of 14-3-3 proteins in neural oscillations that may have implications for our understanding of schizophrenia neurobiology.

Adaptive Balance in Posterior Cerebellum

Vestibular and optokinetic space is represented in three-dimensions in vermal lobules IX-X (uvula, nodulus) and hemisphere lobule X (flocculus) of the cerebellum. Vermal lobules IX-X encodes gravity and head movement using the utricular otolith and the two vertical semicircular canals. Hemispheric lobule X encodes self-motion using optokinetic feedback about the three axes of the semicircular canals. Vestibular and visual adaptation of this circuitry is needed to maintain balance during perturbations of self-induced motion. Vestibular and optokinetic (self-motion detection) stimulation is encoded by cerebellar climbing and mossy fibers. These two afferent pathways excite the discharge of Purkinje cells directly. Climbing fibers preferentially decrease the discharge of Purkinje cells by exciting stellate cell inhibitory interneurons. We describe instances adaptive balance at a behavioral level in which prolonged vestibular or optokinetic stimulation evokes reflexive eye movements that persist when the stimulation that initially evoked them stops. Adaptation to prolonged optokinetic stimulation also can be detected at cellular and subcellular levels. The transcription and expression of a neuropeptide, corticotropin releasing factor (CRF), is influenced by optokinetically-evoked olivary discharge and may contribute to optokinetic adaptation. The transcription and expression of microRNAs in floccular Purkinje cells evoked by long-term optokinetic stimulation may provide one of the subcellular mechanisms by which the membrane insertion of the GABAA receptors is regulated. The neurosteroids, estradiol (E2) and dihydrotestosterone (DHT), influence adaptation of vestibular nuclear neurons to electrically-induced potentiation and depression. In each section of this review, we discuss how adaptive changes in the vestibular and optokinetic subsystems of lobule X, inferior olivary nuclei and vestibular nuclei may contribute to the control of balance.

Biomarkers and diagnostic guidelines for sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease is a fatal neurodegenerative disease caused by misfolded prion proteins (PrP^Sc). Effective therapeutics are currently not available and accurate diagnosis can be challenging. Clinical diagnostic criteria use a combination of characteristic neuropsychiatric symptoms, CSF proteins 14-3-3, MRI, and EEG. Supportive biomarkers, such as high CSF total tau, could aid the diagnostic process. However, discordant studies have led to controversies about the clinical value of some established surrogate biomarkers. Development and clinical application of disease-specific protein aggregation and amplification assays, such as real-time quaking induced conversion (RT-QuIC), have constituted major breakthroughs for the confident pre-mortem diagnosis of sporadic Creutzfeldt-Jakob disease. Updated criteria for the diagnosis of sporadic Creutzfeldt-Jakob disease, including application of RT-QuIC, should improve early clinical confirmation, surveillance, assessment of PrP^Sc seeding activity in different tissues, and trial monitoring. Moreover, emerging blood-based, prognostic, and potentially pre-symptomatic biomarker candidates are under investigation.

Identification of the 14-3-3 β/α-A protein as a novel maternal peptidoglycan-binding protein that protects embryos of zebrafish against bacterial infections

14-3-3 proteins are widespread in animals, but their functions and mechanisms remain poorly defined. Here we clearly demonstrate that 14-3-3 β/α-A is a newly identified PGN-binding protein present abundantly in the eggs/embryos of zebrafish. We also show that recombinant 14-3-3 β/α-A acts as a pattern recognition receptor capable of identifying the bacterial signature molecule PGN, binding the bacteria, and functions as an antibacterial effector molecule directly killing the bacteria. Importantly, microinjection of r14-3-3 β/α-A into early embryos significantly enhanced the resistance of the embryos against pathogenic A. hydrophila challenge, and this enhanced bacterial resistance was markedly reduced by co-injection of anti-14-3-3 β/α-A antibody. Collectively, these results indicate that 14-3-3 β/α-A is a maternal PGN-binding protein that can protect the early embryos of zebrafish against pathogenic attacks, a novel role assigned to 14-3-3 β/α-A proteins. This work also provides new insights into 14-3-3 proteins that are widely distributed in various animals.

The machine learning algorithm for the diagnosis of schizophrenia on the basis of gene expression in peripheral blood

BACKGROUND

Schizophrenia (SCZ) is a highly heritable mental disorder with a substantial disease burden. Machine learning (ML) method can be used to identify individuals with SCZ on the basis of blood gene expression data with high accuracy.

METHODS

This study aimed to differentiate patients with SCZ from healthy individuals by using the messenger RNA expression level in peripheral blood of 48 patients with SCZ and 50 controls via ML algorithms, namely, artificial neural networks, extreme gradient boosting, support vector machine (SVM), decision tree, and random forest. The expression of six mRNAs was detected using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The relative expression levels of GNAI1 (P < 0.001), PRKCA (P < 0.001), and PRKCB (P = 0.021) increased in the SCZ group, whereas those of FYN (P < 0.001), LYN (P = 0.022), and YWHAZ (P < 0.001) decreased in the SCZ group. We generated models with various combinations of genes based on five ML algorithms. The SVM model with six factors (GNAI1, FYN, PRKCA, YWHAZ, PRKCB, and LYN genes) was the best model for distinguishing patients with SCZ from healthy individuals (AUC = 0.993, sensitivity = 1.000, specificity = 0.895, and Youden index = 0.895).

CONCLUSIONS

This study suggested that the combination of genes using the ML method is better than the use of a single gene to discriminate patients with SCZ from healthy individuals. The combination of GNAI1, FYN, PRKCA, YWHAZ, PRKCB, and LYN under the SVM model can be used as a diagnostic biomarker for SCZ.