Dysregulation Of Proteins Research Articles

Multi-omics analysis reveals attenuation of cellular stress by empagliflozin in high glucose-treated human cardiomyocytes

BackgroundSodium–glucose cotransporter 2 (SGLT2) inhibitors constitute the gold standard treatment for type 2 diabetes mellitus (T2DM). Among them, empagliflozin (EMPA) has shown beneficial effects against heart failure. Because cardiovascular diseases (mainly diabetic cardiomyopathy) are the leading cause of death in diabetic patients, the use of EMPA could be, simultaneously, cardioprotective and antidiabetic, reducing the risk of death from cardiovascular causes and decreasing the risk of hospitalization for heart failure in T2DM patients. Interestingly, recent studies have shown that EMPA has positive benefits for people with and without diabetes. This finding broadens the scope of EMPA function beyond glucose regulation alone to include a more intricate metabolic process that is, in part, still unknown. Similarly, this significantly increases the number of people with heart diseases who may be eligible for EMPA treatment.MethodsThis study aimed to clarify the metabolic effect of EMPA on the human myocardial cell model by using orthogonal metabolomics, lipidomics, and proteomics approaches. The untargeted and multivariate analysis mimicked the fasting blood sugar level of T2DM patients (hyperglycemia: HG) and in the average blood sugar range (normal glucose: NG), with and without the addition of EMPA.ResultsResults highlighted that EMPA was able to modulate and partially restore the levels of multiple metabolites associated with cellular stress, which were dysregulated in the HG conditions, such as nicotinamide mononucleotide, glucose-6-phosphate, lactic acid, FA 22:6 as well as nucleotide sugars and purine/pyrimidines. Additionally, EMPA regulated the levels of several lipid sub-classes, in particular dihydroceramide and triacylglycerols, which tend to accumulate in HG conditions resulting in lipotoxicity. Finally, EMPA counteracted the dysregulation of endoplasmic reticulum-derived proteins involved in cellular stress management.ConclusionsThese results could suggest an effect of EMPA on different metabolic routes, tending to rescue cardiomyocyte metabolic status towards a healthy phenotype.Graphical

Adaptor protein complex 2 in the orbitofrontal cortex predicts alcohol use disorder.

Alcohol use disorder (AUD) is a life-threatening disease characterized by compulsive drinking, cognitive deficits, and social impairment that continue despite negative consequences. The inability of individuals with AUD to regulate drinking may involve functional deficits in cortical areas that normally balance actions that have aspects of both reward and risk. Among these, the orbitofrontal cortex (OFC) is critically involved in goal-directed behavior and is thought to maintain a representation of reward value that guides decision making. In the present study, we analyzed post-mortem OFC brain samples collected from age- and sex-matched control subjects and those with AUD using proteomics, bioinformatics, machine learning, and reverse genetics approaches. Of the 4,500+ total unique proteins identified in the proteomics screen, there were 47 proteins that differed significantly by sex that were enriched in processes regulating extracellular matrix and axonal structure. Gene ontology enrichment analysis revealed that proteins differentially expressed in AUD cases were involved in synaptic and mitochondrial function, as well as transmembrane transporter activity. Alcohol-sensitive OFC proteins also mapped to abnormal social behaviors and social interactions. Machine learning analysis of the post-mortem OFC proteome revealed dysregulation of presynaptic (e.g., AP2A1) and mitochondrial proteins that predicted the occurrence and severity of AUD. Using a reverse genetics approach to validate a target protein, we found that prefrontal Ap2a1 expression significantly correlated with voluntary alcohol drinking in male and female genetically diverse mouse strains. Moreover, recombinant inbred strains that inherited the C57BL/6J allele at the Ap2a1 interval consumed higher amounts of alcohol than those that inherited the DBA/2J allele. Together, these findings highlight the impact of excessive alcohol consumption on the human OFC proteome and identify important cross-species cortical mechanisms and proteins that control drinking in individuals with AUD.

Cell senescence induced by toxic interaction between α-synuclein and iron precedes nigral dopaminergic neuron loss in a mouse model of Parkinson's disease.

Cell senescence has been implicated in the pathology of Parkinson's disease (PD). Both abnormal α-synuclein aggregation and iron deposition are suggested to be the triggers, facilitators, and aggravators during the development of PD. In this study, we investigated the involvement of α-synuclein and iron in the process of cell senescence in a mouse model of PD. In order to overexpress α-syn-A53T in the substantia nigra pars compacta (SNpc), human α-syn-A53T was microinjected into both sides of the SNpc in mice. We found that overexpression of α-syn-A53T for one week induced significant pro-inflammatory senescence-associated secretory phenotype (SASP), increased cell senescence-related proteins (β-gal, p16, p21, H2A.X and γ-H2A.X), mitochondrial dysfunction accompanied by dysregulation of iron-related proteins (L-ferritin, H-ferritin, DMT1, IRP1 and IRP2) in the SNpc. In contrast, significant loss of nigral dopaminergic neurons and motor dysfunction were only observed after overexpression of α-syn-A53T for 4 weeks. In PC12 cells stably overexpressing α-syn-A53T, iron overload (ferric ammonium citrate, FAC, 100 μM) not only increased the level of reactive oxygen species (ROS), p16 and p21, but also exacerbated the processes of oxidative stress and cell senescence signalling induced by α-syn-A53T overexpression. Interestingly, reducing the iron level with deferoxamine (DFO) or knockdown of transferrin receptor 1 (TfR1) significantly improved both the phenotypes and dysregulated proteins of cell senescence induced by α-syn-A53T overexpression. All these evidence highlights the toxic interaction between iron and α-synuclein inducing cell senescence, which precedes nigral dopaminergic neuronal loss in PD. Further investigation on cell senescence may yield new therapeutic agents for the prevention or treatment of PD.

Blood Proteome Profiling Reveals Biomarkers and Pathway Alterations in Fragile X PM at Risk for Developing FXTAS.

Fragile X-associated Tremor/Ataxia Syndrome (FXTAS) is a neurodegenerative disorder associated with the FMR1 premutation. Currently, it is not possible to determine when and if individual premutation carriers will develop FXTAS. Thus, with the aim to identify biomarkers for early diagnosis, development, and progression of FXTAS, along with associated dysregulated pathways, we performed blood proteomic profiling of premutation carriers (PM) who, as part of an ongoing longitudinal study, emerged into two distinct groups: those who developed symptoms of FXTAS (converters, CON) over time (at subsequent visits) and those who did not (non-converters, NCON). We compared these groups to age-matched healthy controls (HC). We assessed CGG repeat allele size by Southern blot and PCR analysis. The proteomic profile was obtained by liquid chromatography mass spectrometry (LC-MS/MS). We identified several significantly differentiated proteins between HC and the PM groups at Visit 1 (V1), Visit 2 (V2), and between the visits. We further reported the dysregulated protein pathways, including sphingolipid and amino acid metabolism. Our findings are in agreement with previous studies showing that pathways involved in mitochondrial bioenergetics, as observed in other neurodegenerative disorders, are significantly altered and appear to contribute to the development of FXTAS. Lastly, we compared the blood proteome of the PM who developed FXTAS over time with the CSF proteome of the FXTAS patients recently reported and found eight significantly differentially expressed proteins in common. To our knowledge, this is the first report of longitudinal proteomic profiling and the identification of unique biomarkers and dysregulated protein pathways in FXTAS.

5-Methoxytryptophan alleviates atrial structural remodeling in ibrutinib-associated atrial fibrillation

BackgroundIbrutinib is an effective and well-tolerated treatment for B-cell lymphomas but is associated with an increased risk of atrial fibrillation (AF) by altering the structure of the atrium. 5-Methoxytryptophan (5-MTP) inhibits inflammatory and fibrotic processes. This study aimed to determine the effects and mechanisms of 5-MTP on the underlying mechanisms of AF caused by ibrutinib. MethodsThe effect of 5-MTP on ibrutinib-related AF was investigated in male Sprague Dawley rats using echocardiographic, electrophysiological, immunofluorescent, Masson staining, and molecular analyses. RusultsThe ibrutinib+5-MTP group showed (1) a lower incidence and shorter duration of AF and accelerated atrial conduction; (2) a decreased left atrial mass and left atrial diameter; (3) decreased myocardial fibrosis in the left atrium; (4) lower atrial inflammation; (5) increased sarcoplasmic reticulum Ca2+-ATPase 2a protein expression, decreased phosphorylation of phospholamban at Thr17, and decreased sodium/calcium exchanger 1 protein expression and phosphorylation of ryanodine receptor 2 at S2814; and (6) decreased phosphorylation of CaMKII expression. 5-MTP treatment markedly activated the PI3K-Akt signaling. Inhibiting PI3K-Akt signaling significantly reversed the protective effect of 5-MTP on ibrutinib-related AF. ConclusionsThese findings suggest that 5-MTP administration decreases the vulnerability of ibrutinib-related AF mainly caused by ameliorated maladaptive left atrial remodeling and dysregulation of calcium handling proteins. Mechanistically, 5-MTP treatment markedly enhanced the activation of cardiac PI3K-Akt signaling.

Early-life noise exposure causes cognitive impairment in a sex-dependent manner by disrupting homeostasis of the microbiota–gut–brain axis

Epidemiological investigations show that noise exposure in early life is associated with health and cognitive impairment. The gut microbiome established in early life plays a crucial role in modulating developmental processes that subsequently affect brain function and behavior. Here, we examined the impact of early-life exposure to noise on cognitive function in adolescent rats by analyzing the gut microbiome and metabolome to elucidate the underlying mechanisms. Chronic noise exposure during early life led to cognitive deficits, hippocampal injury, and neuroinflammation. Early-life noise exposure showed significant difference on the composition and function of the gut microbiome throughout adolescence, subsequently causing axis-series changes in fecal short-chain fatty acid (SCFA) metabolism and serum metabolome profiles, as well as dysregulation of endothelial tight junction proteins, in both intestine and brain. We also observed sex-dependent effects of microbiota depletion on SCFA-related beneficial bacteria in adolescence. Experiments on microbiota transplantation and SCFA supplementation further confirmed the role of intestinal bacteria and related SCFAs in early-life noise-exposure-induced impairments in cognition, epithelial integrity, and neuroinflammation. Overall, these results highlight the homeostatic imbalance of microbiota–gut–brain axis as an important physiological response toward environmental noise during early life and reveals subtle differences in molecular signaling processes between male and female rats.

Targeted Lysosomal Degradation of Secreted and Cell Surface Proteins through the LRP-1 Pathway.

Protein dysregulation has been characterized as the cause of pathogenesis in many different diseases. For proteins lacking easily druggable pockets or catalytically active sites, targeted protein degradation is an attractive therapeutic approach. While several methods for targeted protein degradation have been developed, there remains a demand for lower molecular weight molecules that promote efficient degradation of their targets. In this work, we describe the synthesis and validation of a series of heterobifunctional molecules that bind a protein of interest through a small molecule ligand while targeting them to the lysosome using a short gluten peptide that leverages the TG2/LRP-1 pathway. We demonstrate that this approach can be used to effectively endocytose and degrade representative secreted, cell surface, and transmembrane proteins, notably streptavidin, the vitamin B12 receptor, cubilin, and integrin αvβ5. Optimization of these prototypical molecules could generate pharmacologically relevant LYTAC agents.

Metabolic changes and propensity for inflammation, fibrosis, and cancer in livers of mice lacking lysosomal acid lipase

Lysosomal acid lipase (LAL) is the sole lysosomal enzyme responsible for the degradation of cholesteryl esters and triacylglycerols at acidic pH. Impaired LAL activity leads to LAL deficiency (LAL-D), a severe and fatal disease characterized by ectopic lysosomal lipid accumulation. Reduced LAL activity also contributes to the development and progression of non-alcoholic fatty liver disease (NAFLD). To advance our understanding of LAL-related liver pathologies, we performed comprehensive proteomic profiling of livers from mice with systemic genetic loss of LAL (Lal−/−) and from mice with hepatocyte-specific LAL-D (hepLal−/−). Lal−/− mice exhibited drastic proteome alterations, including dysregulation of multiple proteins related to metabolism, inflammation, liver fibrosis, and cancer. Global loss of LAL activity impaired both acidic and neutral lipase activities and resulted in hepatic lipid accumulation, indicating a complete metabolic shift in Lal−/− livers. Hepatic inflammation and immune cell infiltration were evident, with numerous upregulated inflammation-related gene ontology biological process terms. In contrast, both young and mature hepLal−/− mice displayed only minor changes in the liver proteome, suggesting that loss of LAL solely in hepatocytes does not phenocopy metabolic alterations observed in mice globally lacking LAL. These findings provide valuable insights into the mechanisms underlying liver dysfunction in LAL-D and may help in understanding why decreased LAL activity contributes to NAFLD. Our study highlights the importance of LAL in maintaining liver homeostasis and demonstrates the drastic consequences of its global deficiency on the liver proteome and liver function.

Identification of RNA-binding Proteins in Spinal Cord Injury: An In-silico Approach

Introduction: Gene expression is regulated by trans-acting factors such as microRNA, and RNA-binding proteins (RBPs). Dysregulation of RNA-binding proteins (RBPs) are found in neurological diseases. However, the role RBPs in spinal cord injury (SCI) have not been identified. The objective of this study was to identify RBPs by re-analyzing RNA-sequencing data from SCI mice model using the latest version of Tuxedo pipeline. Methods: Reads from transcriptomic sequence of acute, subacute, and control mice models, from the Sequence Read Archive (SRA) website, were uploaded to a scientific workflow system called usegalaxy.org. The reads were assessed for their quality using FastQC, before they were mapped to the mouse mm10 reference genome using HISAT2. The fragments were then aligned to full-length transcripts using Stringtie, followed by DESeq2 to find differentially expressed genes (false discovery rate of 0.05 and fold change of -1< x >1). Finally, to find functional annotations, the Protein Analysis through Evolutionary Relationship (PANTHER) and g:Profiler were used. Results: There were 24 RBP-coding genes identified in the acute injury, and 27 in the subacute injury. Four RBPs that were commonly expressed at high levels in both acute and subacute injury; Hnrnpm, Ptbp3, Rbfox3 and Znf385a. These proteins regulate alternative splicing, and RNA transport. Other RBP-coding genes with a role in inflammatory response and apoptosis were also discovered. Conclusion: Novel RBP-coding genes differentially expressed in SCI were discovered, suggesting their role in the pathophysiology of SCI. These findings contribute to a better understanding of the regulatory mechanisms employed by RBPs in SCI.

COVIDpro: Database for Mining Protein Dysregulation in Patients with COVID-19.

The ongoing pandemic of the coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 still has limited treatment options. Our understanding of the molecular dysregulations that occur in response to infection remains incomplete. We developed a web application COVIDpro (https://www.guomics.com/covidPro/) that includes proteomics data obtained from 41 original studies conducted in 32 hospitals worldwide, involving 3077 patients and covering 19 types of clinical specimens, predominantly plasma and serum. The data set encompasses 53 protein expression matrices, comprising a total of 5434 samples and 14,403 unique proteins. We identified a panel of proteins that exhibit significant dysregulation, enabling the classification of COVID-19 patients into severe and non-severe disease categories. The proteomic signatures achieved promising results in distinguishing severe cases, with a mean area under the curve of 0.87 and accuracy of 0.80 across five independent test sets. COVIDpro serves as a valuable resource for testing hypotheses and exploring potential targets for novel treatments in COVID-19 patients.

Skeletal muscle cell protein dysregulation highlights the pathogenesis mechanism of myopathy-associated p97/VCP R155H mutations.

p97/VCP, a hexametric member of the AAA-ATPase superfamily, has been associated with a wide range of cellular protein pathways, such as proteasomal degradation, the unfolding of polyubiquitinated proteins, and autophagosome maturation. Autosomal dominant p97/VCP mutations cause a rare hereditary multisystem disorder called IBMPFD/ALS (Inclusion Body Myopathy with Paget's Disease and Frontotemporal Dementia/Amyotrophic Lateral Sclerosis), characterized by progressive weakness and subsequent atrophy of skeletal muscles, and impacting bones and brains, such as Parkinson's disease, Lewy body disease, Huntington's disease, and amyotrophic lateral ALS. Among all disease-causing mutations, Arginine 155 to Histidine (R155H/+) was reported to be the most common one, affecting over 50% of IBMPFD patients, resulting in disabling muscle weakness, which might eventually be life-threatening due to cardiac and respiratory muscle involvement. Induced pluripotent stem cells (iPSCs) offer an unlimited resource of cells to study pathology's underlying molecular mechanism, perform drug screening, and investigate regeneration. Using R155H/+ patients' fibroblasts, we generated IPS cells and corrected the mutation (Histidine to Arginine, H155R) to generate isogenic control cells before differentiating them into myotubes. The further proteomic analysis allowed us to identify differentially expressed proteins associated with the R155H mutation. Our results showed that R155H/+ cells were associated with dysregulated expression of several proteins involved in skeletal muscle function, cytoskeleton organization, cell signaling, intracellular organelles organization and function, cell junction, and cell adhesion. Our findings provide molecular evidence of dysfunctional protein expression in R155H/+ myotubes and offer new therapeutic targets for treating IBMPFD/ALS.

Longitudinal Serum Proteomics Characterization of CD19-CAR-T Cell Therapy for B-Cell Malignancies.

Chimeric antigen receptor (CAR)-modified T cells have demonstrated remarkable efficacy in treating B-cell leukemia. However, treated patients may potentially develop side effects, such as cytokine release syndrome (CRS), the mechanisms of which remain unclear. Here, we collected 43 serum samples from eight patients with B-cell acute lymphoblastic leukemia (B-ALL) before and five time points after CD19-specific CAR-T cell treatment. Using TMTpro 16-plex-based quantitative proteomics, we quantified 1151 proteins and profiled the longitudinal proteomes analysis of each patient. Seven days after therapy, we found the most dysregulated inflammatory proteins. Lipid metabolism proteins, including APOA1, decreased after therapy, reached their minimum after 7 days, and then gradually recovered. Hence, APOA1 has been selected as a potential biomarker of the CRS disease progression. Furthermore, we identified CD163 as a potential biomarker of CRS severity. These two biomarkers were successfully validated using targeted proteomics in an independent cohort. Our study provides new insights into CAR-T cell therapy-induced CRS. The biomarkers we identified may help develop targeted drugs and monitoring strategies.

Overview of the Molecular Modalities and Signaling Pathways Intersecting with β-Amyloid and Tau Protein in Alzheimer’s Disease

Alzheimer’s disease (AD) is one of the major causes of dementia and its incidence represents approximately 60–70% of all dementia cases worldwide. Many theories have been proposed to describe the pathological events in AD, including deterioration in cognitive function, accumulation of β-amyloid, and tau protein hyperphosphorylation. Infection as well as various cellular molecules, such as apolipoprotein, micro-RNA, calcium, ghrelin receptor, and probiotics, are associated with the disruption of β-amyloid and tau protein hemostasis. This review gives an overview on the integrative cellular and signaling molecules that could play a complementary role in the dysregulation of β-amyloid and tau proteins.

Structural and functional fine mapping of cysteines in mammalian glutaredoxin reveal their differential oxidation susceptibility

Protein-S-glutathionylation is a post-translational modification involving the conjugation of glutathione to protein thiols, which can modulate the activity and structure of key cellular proteins. Glutaredoxins (GLRX) are oxidoreductases that regulate this process by performing deglutathionylation. However, GLRX has five cysteines that are potentially vulnerable to oxidative modification, which is associated with GLRX aggregation and loss of activity. To date, GLRX cysteines that are oxidatively modified and their relative susceptibilities remain unknown. We utilized molecular modeling approaches, activity assays using recombinant GLRX, coupled with site-directed mutagenesis of each cysteine both individually and in combination to address the oxidizibility of GLRX cysteines. These approaches reveal that C8 and C83 are targets for S-glutathionylation and oxidation by hydrogen peroxide in vitro. In silico modeling and experimental validation confirm a prominent role of C8 for dimer formation and aggregation. Lastly, combinatorial mutation of C8, C26, and C83 results in increased activity of GLRX and resistance to oxidative inactivation and aggregation. Results from these integrated computational and experimental studies provide insights into the relative oxidizability of GLRX’s cysteines and have implications for the use of GLRX as a therapeutic in settings of dysregulated protein glutathionylation.

Cell-type-specific disruption of cortico-striatal circuitry drives repetitive patterns of behavior in fragile X syndrome model mice

Individuals with fragile X syndrome (FXS) are frequently diagnosed with autism spectrum disorder (ASD), including increased risk for restricted and repetitive behaviors (RRBs). Consistent with observations in humans, FXS model mice display distinct RRBs and hyperactivity that are consistent with dysfunctional cortico-striatal circuits, an area relatively unexplored in FXS. Using a multidisciplinary approach, we dissect the contribution of two populations of striatal medium spiny neurons (SPNs) in the expression of RRBs in FXS model mice. Here, we report that dysregulated protein synthesis at cortico-striatal synapses is a molecular culprit of the synaptic and ASD-associated motor phenotypes displayed by FXS model mice. Cell-type-specific translational profiling of the FXS mouse striatum reveals differentially translated mRNAs, providing critical information concerning potential therapeutic targets. Our findings uncover a cell-type-specific impact of the loss of fragile X messenger ribonucleoprotein (FMRP) on translation and the sequence of neuronal events in the striatum that drive RRBs in FXS.

Necroptosis in human cancers with special emphasis on oral squamous cell carcinoma

Necroptosis is a type of caspase independent ‘programmed or regulated’ necrotic cell death that has a morphological resemblance to necrosis and mechanistic analogy to apoptosis. This type of cell death requires RIPK1, RIPK3, MLKL, death receptors, toll like receptors, interferons, and various other proteins. Necroptosis is implicated in plethora of diseases like rheumatoid arthritis, Alzheimer's disease, Crohn's disease, and head and neck cancers including oral squamous cell carcinoma. Oral carcinomas show dysregulation or mutation of necroptotic proteins, mediate antitumoral immunity, activate immune response and control tumor progression. Necroptosis is known to play a dual role (pro tumorigenic and anti-tumorigenic) in cancer progression and targeting this pathway could be an effective approach in cancer therapy. Necroptosis based chemotherapy has been proposed in malignancies, highlighting the importance of necroptotic pathway to overcome apoptosis resistance and serve as a “fail-safe” pathway to modulate cancer initiation, progression, and metastasis. However, there is dearth of information regarding the use of necroptotic cell death mechanism in the treatment of oral squamous cell carcinoma. In this review, we summarise molecular mechanism of necroptosis, and its protumorigenic and antitumorigenic role in cancers to shed light on the possible therapeutic significance of necroptosis in oral squamous cell carcinoma.

Exome sequencing links the SUMO protease SENP7 with fatal arthrogryposis multiplex congenita, early respiratory failure and neutropenia

BackgroundSUMOylation involves the attachment of small ubiquitin-like modifier (SUMO) proteins to specific lysine residues on thousands of substrates with target-specific effects on protein function. Sentrin-specific proteases (SENPs) are proteins involved...

Molecular Analysis of Radiation Resistance Process in Radioresistant Oesophageal Adenocarcinoma Cells

Background: The radiation resistance process is a major problem in radiotherapy. Proteomics is a useful method to determine the molecular mechanism of biological and medical events. Protein-protein interaction (PPI) network is a suitable method for proteomics data interpretation. Objectives: Assessment of proteomics data about the radiation resistance process in human cell lines via PPI network analysis is the aim of this study. Methods: Proteomic data were extracted from literature and the differentially expressed proteins (DEPs) were included in the PPI network via the STRING database by Cytoscape software. The network was analyzed and the central nodes were introduced. The central nodes were assessed via action map analysis and gene ontology enrichment. Results: Among the 251 queried DEPs, 171 individuals were included in the PPI network. Epidermal growth factor receptor (EGFR), fibronectin (FN1), CD44 antigen (CD44), prostaglandin G/H synthase 2 (PTGS2), CD44 antigen (CD44), prostaglandin G/H synthase 2 (PTGS2), NF-kappa-B inhibitor alpha (NFKBIA), Kelch-like ECH-associated protein 1 (KEAP1), cathepsin D (CTSD), D-3-phosphoglycerate dehydrogenase (PHGD), and 5-nucleotidase (NT5E) were introduced as the critical DEPs. Eight groups of biological terms were attributed to the introduced critical DEPs. EGFR, FN1, CD44, and PTGS2 were discriminated among the critical DEPs as the key dysregulated proteins. Conclusions: The results indicate that EGFR, FN1, CD44, and PTGS2 are the four essential proteins that are involved in radiation resistance in the radioresistant cells.

SYMPTOM SEVERITY IN SCHIZOPHRENIA PATIENTS WITH NPAS3, DYSBINDIN-1 AND/OR TRIOBP PROTEIN PATHOLOGY IN THEIR BLOOD SERUM: A PANSS-BASED FOLLOW UP STUDY.

It has been proposed that aggregation of specific proteins in the brain may be a pathological element in schizophrenia and other chronic disorders. Multiple such aggregating proteins have now been implicated through post mortem investigation, including NPAS3 (Neuronal PAS domain protein 3), dysbindin-1 (encoded by the DTNBP1, Dystrobrevin Binding Protein 1, gene) and TRIOBP (Trio-Binding Protein, multiple isoforms). While the presence of protein aggregates in the brain is interesting in terms of understanding pathology, it is impractical as a biomarker. These proteins were therefore investigated recently in blood serum of schizophrenia patients and controls, showing patients to have higher levels of NPAS3 in their serum generally. TRIOBP-1 and dysbindin-1 were also found in an insoluble state, implying aggregation, but did not clearly corresponding to disease state. We revisit 47 of the originally recruited 50 patients with schizophrenia, all of whom are Croatian and aged between 18 and 72. We assessed their symptom specificity and severity using PANSS (the Positive and Negative Symptoms Scale), comparing those with NPAS3, insoluble dysbindin-1 and/or insoluble TRIOBP-1 in their blood serum to those lacking any such protein dysregulation. The frequency of each individual potential protein pathology among these patients was too low for meaningful statistical analysis, however the 11 patients that displayed one or more of these pathologies (NPAS3, dysbindin-1, TRIOBP-1 and/or TRIOBP-5/6) showed a subtle but significant increase in total PANSS scores compared to the 36 patients displaying none of the pathologies (p = 0.031), seemingly driven principally by increased scores on the general psychopathology scale. While the numbers of patients involved do not allow firm conclusions to be drawn at this time, this provides the first indication that disturbed proteostasis in blood serum, of proteins that aggregate in the brains of schizophrenia patients, may correlate with the severity of schizophrenia symptoms.

Effects of heterozygous deletion of autism-related gene Cullin-3 in mice.

Autism Spectrum Disorder (ASD) is a developmental disorder in which children display repetitive behavior, restricted range of interests, and atypical social interaction and communication. CUL3, coding for a Cullin family scaffold protein mediating assembly of ubiquitin ligase complexes through BTB domain substrate-recruiting adaptors, has been identified as a high-risk gene for autism. Although complete knockout of Cul3 results in embryonic lethality, Cul3 heterozygous mice have reduced CUL3 protein, demonstrate comparable body weight, and display minimal behavioral differences including decreased spatial object recognition memory. In measures of reciprocal social interaction, Cul3 heterozygous mice behaved similarly to their wild-type littermates. In area CA1 of hippocampus, reduction of Cul3 significantly increased mEPSC frequency but not amplitude nor baseline evoked synaptic transmission or paired-pulse ratio. Sholl and spine analysis data suggest there is a small yet significant difference in CA1 pyramidal neuron dendritic branching and stubby spine density. Unbiased proteomic analysis of Cul3 heterozygous brain tissue revealed dysregulation of various cytoskeletal organization proteins, among others. Overall, our results suggest that Cul3 heterozygous deletion impairs spatial object recognition memory, alters cytoskeletal organization proteins, but does not cause major hippocampal neuronal morphology, functional, or behavioral abnormalities in adult global Cul3 heterozygous mice.