Biology subjects

Wakid, M.

Publications and source records attributed to Wakid, M..

3 recordsLinked to original sources

bioRxiv2024

Pervasive neurovascular dysfunction in the ventromedial prefrontal cortex of female depressed suicides with a history of childhood abuse

Exposure to early life adversity (ELA) poses a significant global public health concern, with profound pathophysiological implications for affected individuals. Studies suggest that ELA contributes to endothelial dysfunction, bringing into question the functional integrity of the neurovascular unit in brain regions vulnerable to chronic stress. Despite the importance of the neurovasculature in maintaining normal brain physiology, human neurovascular cells remain poorly characterized, particularly with regard to their contributory role in ELA-associated pathophysiologies. In this study, we present the first comprehensive transcriptomic analysis of intact microvessels isolated from postmortem ventromedial prefrontal cortex samples from adult healthy controls (CTRL) and matched depressed suicides with histories of ELA. Our findings point to substantive differences between men and women, with the latter exhibiting widespread gene expression changes at the neurovascular unit, including the key vascular nodal regulators KLF2 and KLF4, alongside a broad downregulation of immune-related pathways. These results suggest that the neurovascular unit plays a larger role in the neurobiological consequences of ELA in human females.

neuroscience↗

bioRxiv2023

Universal method for the gentle isolation of intact microvessels from frozen tissue: a multiomic investigation into the neurovasculature

The neurovascular unit (NVU), comprised of endothelial cells, pericytes, smooth muscle cells, astrocytic endfeet and microglia together with neurons, is paramount for the proper function of the central nervous system. The NVU gatekeeps blood-brain barrier (BBB) properties which, as a system, experiences impairment in several neurological and psychiatric diseases, and contributes to pathogenesis. To better understand function and dysfunction at the NVU, isolation and characterization of the NVU is needed. Here, we describe a singular, standardized protocol to enrich and isolate microvessels from archived snap-frozen human and frozen mouse cerebral cortex using mechanical homogenization and centrifugation-separation that preserves the structural integrity and multicellular composition of microvessel fragments. For the first time, microvessels are isolated from postmortem vmPFC tissue and are comprehensively investigated using both RNA sequencing and Liquid Chromatography with tandem mass spectrometry (LC-MS-MS). Both the transcriptome and proteome are elucidated and compared, demonstrating that the isolated brain microvessel is a robust model for the NVU and can be used to generate highly informative datasets in both physiological and disease contexts.

neuroscience↗

bioRxiv2021

Neuron-derived extracellular vesicles extracted from plasma show altered size and miRNA cargo as a function of antidepressant drug response

Previous work has demonstrated that microRNAs (miRNAs) change as a function of antidepressant treatment (ADT) response. However, it is unclear how representative these peripherally detected miRNA changes are to those occurring in the brain. This study aimed to use peripherally extracted neuron-derived extracellular vesicles (NDEVs) to circumvent these limitations and investigate neuronal miRNA changes associated with antidepressant response. Samples were collected at two time points (baseline and after 8 weeks of follow-up) from depressed patients who responded (N=20) and did not respond (N=20) to escitalopram treatment, as well as controls (N=20). Total extracellular vesicles (EVs) were extracted from plasma, and then further enriched for NDEVs by immunoprecipitation with L1CAM. EV size was measured using tunable resistive pulse sensing, and NDEV miRNA cargo was extracted and sequenced. Subsequently, studies in cell lines and postmortem tissue were conducted. Characterization of NDEVs revealed they were smaller than other EVs isolated from plasma (p<0.0001), had brain-specific neuronal markers, and contained miRNAs enriched for brain functions (p<0.0001) Furthermore, NDEVs from depressed patients were smaller than controls (p<0.05), and NDEV size increased with ADT response (p<0.01). Finally, changes in NDEV cargo, specifically changes in miR-21-5p, miR-30d-5p and miR-486-5p together (p<0.01), were associated with ADT response. Targets of these three miRNAs were altered in brain tissue from depressed individuals (p<0.05). Together, this study indicates that changes in peripherally isolated NDEVs can act as both a clinically accessible and informative biomarker of ADT response specifically through size and cargo.

neuroscience↗