Partitioning the proteome: phase separation for targeted analysis of membrane proteins in human post-mortem brain

Mind-life continuity: A qualitative study of conscious experience

There are two fundamental models to understanding the phenomenon of natural life. One is the computational model, which is based on the symbolic thinking paradigm. The other is the biological organism model. The common difficulty attributed to these paradigms is that their reductive tools allow the phenomenological aspects of experience to remain hidden behind yes/no responses (behavioral tests), or brain 'pictures' (neuroimaging). Hence, one of the problems regards how to overcome methodological difficulties towards a non-reductive investigation of conscious experience. It is our aim in this paper to show how cooperation between Eastern and Western traditions may shed light for a non-reductive study of mind and life. This study focuses on the first-person experience associated with cognitive and mental events. We studied phenomenal data as a crucial fact for the domain of living beings, which, we expect, can provide the ground for a subsequent third-person study. The intervention with Jhana meditation, and its qualitative assessment, provided us with experiential profiles based upon subjects' evaluations of their own conscious experiences. The overall results should move towards an integrated or global perspective on mind where neither experience nor external mechanisms have the final word.

Label-free proteomic analysis of the hydrophobic membrane protein complement in articular chondrocytes: a technique for identification of membrane biomarkers

CONTEXT

There is insufficient knowledge about the chondrocyte membranome and its molecular composition.

OBJECTIVE

To develop a Triton X-114 based separation technique using nanoLC-MS/MS combined with shotgun proteomics to identify chondrocyte membrane proteins.

MATERIALS AND METHODS

Articular chondrocytes from equine metacarpophalangeal joints were separated into hydrophobic and hydrophilic fractions; trypsin-digested proteins were analysed by nanoLC-MS/MS.

RESULTS

A total of 315 proteins were identified. The phase extraction method yielded a high proportion of membrane proteins (56%) including CD276, S100-A6 and three VDAC isoforms.

DISCUSSION

Defining the chondrocyte membranome is likely to reveal new biomarker targets for conventional and biological drug discovery.

Transformative Impact of Proteomics on Cardiovascular Health and Disease: A Scientific Statement From the American Heart Association

The year 2014 marked the 20th anniversary of the coining of the term proteomics. The purpose of this scientific statement is to summarize advances over this period that have catalyzed our capacity to address the experimental, translational, and clinical implications of proteomics as applied to cardiovascular health and disease and to evaluate the current status of the field. Key successes that have energized the field are delineated; opportunities for proteomics to drive basic science research, facilitate clinical translation, and establish diagnostic and therapeutic healthcare algorithms are discussed; and challenges that remain to be solved before proteomic technologies can be readily translated from scientific discoveries to meaningful advances in cardiovascular care are addressed. Proteomics is the result of disruptive technologies, namely, mass spectrometry and database searching, which drove protein analysis from 1 protein at a time to protein mixture analyses that enable large-scale analysis of proteins and facilitate paradigm shifts in biological concepts that address important clinical questions. Over the past 20 years, the field of proteomics has matured, yet it is still developing rapidly. The scope of this statement will extend beyond the reaches of a typical review article and offer guidance on the use of next-generation proteomics for future scientific discovery in the basic research laboratory and clinical settings.

New insights into the human brain proteome: Protein expression profiling of deep brain stimulation target areas

Deep brain stimulation (DBS) is a neurosurgical procedure that provides therapeutic benefits for movement and affective disorders. The nucleus basalis of Meynert (NBM) and substantia nigra (SN) are considered target areas to apply DBS. Even though the degeneration of NBM and SN underlies the cognitive decline observed in neurological diseases, the protein knowledge derived from both areas is scarce. We have characterized the proteome present in both subcortical brain areas using the Triple TOF 5600 mass spectrometer, identifying 2775 and 3469 proteoforms in NBM and SN respectively. Data mining of MS-generated proteomic data have revealed that: i) 675 proteins tend to localize to synaptic ending, ii) 61% of the global dataset is also present in human CSF and/or plasma, and iii) 894 proteins have not been previously identified in healthy brain by MS. The correlation of NBM and SN proteomic expression profiles with human brain transcriptome data available at Allen Brain Atlas has revealed protein evidence for 250 genes considered with brain-wide expression and 112 genes with region-specific expression in human brain. In addition, protein datasets have been classified according to their chromosomal origin, increasing the current proteome coverage in healthy human brain.

BIOLOGICAL SIGNIFICANCE

The nucleus basalis of Meynert and substantia nigra are brain areas of clinical interest to apply the deep brain stimulation (DBS) technology in neurosurgery. Our proteomic characterization has revealed 675 proteins involved in the regulation of synaptic transmission, electrical machinery, and neurotransmitter release in both DBS target areas. Moreover, 2599 identified proteins present capacity to be secreted to the CSF and plasma. Our data contribute to a further step towards the characterization of the anatomical atlas of the human brain proteome, detecting 652 proteins that are common between different basal ganglia structures. This article is part of a Special Issue entitled: HUPO 2014.

Proteomic and genomic evidence implicates the postsynaptic density in schizophrenia

The postsynaptic density (PSD) contains a complex set of proteins of known relevance to neuropsychiatric disorders, and schizophrenia specifically. We enriched for this anatomical structure, in the anterior cingulate cortex, of 20 schizophrenia samples and 20 controls from the Stanley Medical Research Institute, and used unbiased shotgun proteomics incorporating label-free quantitation to identify differentially expressed proteins. Quantitative investigation of the PSD revealed more than 700 protein identifications and 143 differentially expressed proteins. Prominent among these were altered expression of proteins involved in clathrin-mediated endocytosis (CME) (Dynamin-1, adaptor protein 2) and N-methyl-D-aspartate (NMDA)-interacting proteins such as CYFIP2, SYNPO, SHANK3, ESYT and MAPK3 (all P<0.0015). Pathway analysis of the differentially expressed proteins implicated the cellular processes of endocytosis, long-term potentiation and calcium signaling. Both single-gene and gene-set enrichment analyses in genome-wide association data from the largest schizophrenia sample to date of 13,689 cases and 18,226 controls show significant association of HIST1H1E and MAPK3, and enrichment of our PSD proteome. Taken together, our data provide robust evidence implicating PSD-associated proteins and genes in schizophrenia, and suggest that within the PSD, NMDA-interacting and endocytosis-related proteins contribute to disease pathophysiology.

Toward defining the anatomo-proteomic puzzle of the human brain: An integrative analysis

The human brain is exceedingly complex, constituted by billions of neurons and trillions of synaptic connections that, in turn, define ∼900 neuroanatomical subdivisions in the adult brain (Hawrylycz et al. An anatomically comprehensive atlas of the human brain transcriptome. Nature 2012, 489, 391-399). The human brain transcriptome has revealed specific regional transcriptional signatures that are regulated in a spatiotemporal manner, increasing the complexity of the structural and molecular organization of this organ (Kang et al. Spatio-temporal transcriptome of the human brain. Nature 2011, 478, 483-489). During the last decade, neuroproteomics has emerged as a powerful approach to profile neural proteomes using shotgun-based MS, providing complementary information about protein content and function at a global level. Here, we revise recent proteome profiling studies performed in human brain, with special emphasis on proteome mapping of anatomical macrostructures, specific subcellular compartments, and cerebrospinal fluid. Moreover, we have performed an integrative functional analysis of the protein compilation derived from these large-scale human brain proteomic studies in order to obtain a comprehensive view of human brain biology. Finally, we also discuss the potential contribution of our meta-analysis to the Chromosome-centric Human Proteome Project initiative.

Omega-3 fatty acid deficiency disrupts endocytosis, neuritogenesis, and mitochondrial protein pathways in the mouse hippocampus

Omega-3 fatty acid (n-3 FA) deficiency is an environmental risk factor for schizophrenia, yet characterization of the consequences of deficiency at the protein level in the brain is limited. We aimed to identify the protein pathways disrupted as a consequence of chronic n-3 deficiency in the hippocampus of mice. Fatty acid analysis of the hippocampus following chronic dietary deficiency revealed a 3-fold decrease (p < 0.001) in n-3 FA levels. Label free LC-MS/MS analysis identified and profiled 1008 proteins, of which 114 were observed to be differentially expressed between n-3 deficient and control groups (n = 8 per group). The cellular processes that were most implicated were neuritogenesis, endocytosis, and exocytosis, while specific protein pathways that were most significantly dysregulated were mitochondrial dysfunction and clathrin mediated endocytosis (CME). In order to characterize whether these processes and pathways are ones influenced by antipsychotic medication, we used LC-MS/MS to test the differential expression of these 114 proteins in the hippocampus of mice chronically treated with the antipsychotic agent haloperidol. We observed 23 of the 114 proteins to be differentially expressed, 17 of which were altered in the opposite direction to that observed following n-3 deficiency. Overall, our findings point to disturbed synaptic function, neuritogenesis, and mitochondrial function as a consequence of dietary deficiency in n-3 FA. This study greatly aids our understanding of the molecular mechanism by which n-3 deficiency impairs normal brain function, and provides clues as to how n-3 FA exert their therapeutic effect in early psychosis.