Biology subjects

Haqqani, A. S.

Publications and source records attributed to Haqqani, A. S..

3 recordsLinked to original sources

bioRxiv2023

Assessment of brain-derived extracellular vesicle enrichment for blood biomarker analysis in age-related neurodegenerative diseases: An international overview

INTRODUCTIONBrain-derived extracellular vesicles (BEVs) in blood allows for minimally- invasive investigations of CNS-specific markers of age-related neurodegenerative diseases (NDDs). Polymer-based EV- and immunoprecipitation (IP)-based BEV-enrichment protocols from blood have gained popularity. We systematically investigated protocol consistency across studies, and determined CNS-specificity of proteins associated with these protocols. METHODSNDD articles investigating BEVs in blood using polymer-based and/or IP-based BEV enrichment protocols were systematically identified, and protocols compared. Proteins used for BEV-enrichment and/or post-enrichment were assessed for CNS- and brain-cell-type- specificity; extracellular domains (ECD+); and presence in EV-databases. RESULTS82.1% of studies used polymer-based (ExoQuick) EV-enrichment, and 92.3% used L1CAM for IP-based BEV-enrichment. Centrifugation times differed across studies. 26.8% of 82 proteins systematically identified were CNS-specific: 50% ECD+, 77.3% were listed in EV- databases. DISCUSSIONWe identified protocol steps requiring standardization, and recommend additional CNS-specific proteins that can be used for BEV-enrichment or as BEV-biomarkers.

neuroscience↗

bioRxiv2023

Proteome profiling of brain vessels in a mouse model of cerebrovascular pathology

A cerebrovascular pathology that involves altered protein levels or signaling of the transforming growth factor beta (TGF{beta}) family has been associated with various forms of dementia, including Alzheimer disease (AD) and vascular cognitive impairment and dementia (VCID). Transgenic mice overexpressing TGF{beta}1 in the brain (TGF mice) recap VCID-associated cerebrovascular pathology and develop cognitive deficits in old age or when submitted to comorbid cardiovascular risk-factors for dementia. Here, we characterized the cerebrovascular proteome of TGF mice using mass-spectrometry (MS) based quantitative proteomics. Cerebral arteries were surgically removed from 6-month-old-TGF and wild-type mice, proteins extracted and analyzed by gel-free nanoLC-MS/MS. We identified 3,602 proteins in brain vessels, with 20 demonstrating robust altered levels in TGF mice. For total and/or differentially-expressed proteins (p[≤]0.01, [≥]2-fold change), using multiple databases, we performed protein characterization, and identified proteins demonstrating RNA-transcripts in both mouse and human cerebrovascular cells, and known to be present in human-extracellular-vesicles (EVs). Dysregulated proteins point to perturbed brain vessel vasomotricity, remodeling, and inflammation. Given that blood-isolated EVs are novel, attractive and a minimally invasive biomarker discovery platform for the age-related dementias, several proteins identified in this study can potentially serve as VCID markers in humans.

neuroscience↗

bioRxiv2019

The E3 ubiquitin ligase TRAF6 is a novel interacting protein of amyotrophic lateral sclerosis-linked misfolded SOD1

Amyotrophic lateral sclerosis (ALS) is a fatal disease, characterized by the selective loss of motor neurons leading to paralysis. Mutations in the gene encoding superoxide dismutase 1 (SOD1) are the second most common cause of familial ALS, and considerable evidence suggests that these mutations result in an increase in toxicity due to protein misfolding. We previously demonstrated in the SOD1G93A rat model that misfolded SOD1 exists as distinct conformers and forms deposits on mitochondrial subpopulations. Here, using SOD1G93A rats and conformation-restricted antibodies specific for misfolded SOD1 (B8H10 and AMF7-63), we identified the interactomes of the mitochondrial pools of misfolded SOD1. This strategy identified binding proteins that uniquely interacted with either AMF7-63 or B8H10-reactive SOD1 conformers as well as with a high proportion of interactors common to both conformers. Of this latter set, we identified the E3 ubiquitin ligase TNF receptor-associated factor 6 (TRAF6) as a SOD1 interactor and determined that exposure of the SOD1 functional loops facilitates this interaction. Of note, this conformational change was not universally fulfilled by all SOD1 variants and differentiated TRAF6-interacting from TRAF6 non-interacting SOD1 variants. Functionally, TRAF6 stimulated polyubiquitination and aggregation of the interacting SOD1 variants. TRAF6 E3 ubiquitin ligase activity was required for the former, but was dispensable for the latter, indicating that TRAF6-mediated polyubiquitination and aggregation of the SOD1 variants are independent events. We propose that the interaction between misfolded SOD1 and TRAF6 may be relevant to the etiology of ALS.

neuroscience↗