Sherif Rashad

Sherif Rashad
Tohoku University | Tohokudai · Graduate School of Medicine

MD, PhD

About

51
Publications
7,718
Reads
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592
Citations
Introduction
I am interested mainly in cellular stress responses and epigenetic and epitranscriptional regulators of proteostasis during stress response. In my group, we combine fundamental research topics with disease-oriented approaches in order to accelerate the implementation of new research findings into translational research. Of the diseases & processes we currently study we focus on: Stroke, Brain oncologies, Neural regeneration, Alzheimer's disease, cerebrovascular diseases and others.
Additional affiliations
April 2018 - present
Tohoku University
Position
  • Professor (Assistant)
October 2014 - March 2018
Tohoku University
Position
  • PhD Student
January 2011 - September 2014
Alexandria University
Position
  • Senior resident of neurosurgery and interventional neuroradiology
Education
October 2014 - March 2018
Tohoku University
Field of study
  • Medical Sciences
December 2010 - March 2014
Alexandria Faculty of Medicine
Field of study
  • Surgery
September 2002 - October 2008
Alexandria Faculty of Medicine
Field of study
  • Medicine and Surgery

Publications

Publications (51)
Article
Full-text available
OBJECTIVE Risk factors for aneurysm rupture have been extensively studied, with several factors showing significant correlations with rupture status. Several studies have shown that aneurysm shape and hemodynamics change after rupture. In the present study the authors investigated a static factor, the bifurcation angle, which does not change after...
Article
Sphingosine-1-phosphate (S1P) is a sphingolipid molecule produced by the action of sphingosine kinases (SphK) on sphingosine. It possesses various intracellular functions through its interactions with intracellular proteins or via its action on five G-protein-coupled cell membrane receptors. Following transient global cerebral ischaemia (tGCI), onl...
Article
The disruption of appropriate cellular stress responses is implicated in the pathogenesis of different neurological disorders including ischemic injury. Early diagnosis and treatment are often associated with better prognosis in ischemic stroke patients. Thus, there is an urgent need to improve the speed and accuracy of stroke diagnosis by developi...
Article
Full-text available
Despite the plethora of published studies on intracranial aneurysms (IAs) hemodynamic using computational fluid dynamics (CFD), limited progress has been made towards understanding the complex physics and biology underlying IA pathophysiology. Guided by 1733 published papers, we review and discuss the contemporary IA hemodynamics paradigm establish...
Article
Endothelial cells (ECs) respond to flow stress via a variety of mechanisms, leading to various intracellular responses that can modulate the vessel wall and lead to diseases if the flow is disturbed. Mechano-microRNAs (miRNAs) are a subset of miRNAs in the ECs that are flow responsive. Mechano-miRNAs were shown to be related to atherosclerosis path...
Article
RNF213 gene mutations are the cause behind Moyamoya disease, a rare cerebrovascular occlusive disease. However, the function of RNF213 in the vascular system and the impact of its loss of function are not yet comprehended. To understand RNF23 function, we performed gene knockdown (KD) in vascular cells and performed various phenotypical analysis as...
Preprint
Full-text available
Rationale Moyamoya disease (MMD) is a rare cerebrovascular occlusive disease that affects Asian population more often. The pathogenesis of MMD is related to mutation in RNF213 gene. However, why, and how RNF213 mutation leads to MMD is still not fully understood. Objective Analyze the impact of RNF213 loss of function on vascular cells and the obs...
Article
Full-text available
Endovascular stents have become a standard management procedure for carotid artery stenosis. Recent discoveries related to the complex turbulence dynamics in blood flow necessitate revisiting the pathology of carotid stenosis itself and the impact of stenting on blood hemodynamics. In the present work, and for the first time, the therapeutic hemody...
Preprint
Full-text available
Neuronal differentiation is a complex process that entails extensive morphological, transcriptional, metabolic, and functional changes that dictate neuronal lineage commitment. Much less understood is the role that epigenetic and epi-transcriptional reprogramming plays in the process of neuronal differentiation and maturation. To depict the whole l...
Preprint
Full-text available
Ferroptosis is a non-apoptotic cell death mechanism characterized by the production of lipid peroxides. Ferroptosis plays important roles in many diseases such as cancer and neurodegenerative diseases. While many effectors in the ferroptosis pathway have been mapped, its epigenetic and epitranscriptional regulatory processes are not yet fully under...
Article
Growing evidence suggest the association between Moyamoya disease (MMD) and immune systems, such as antigen presenting cells in particular. Rnf213 gene, a susceptibility gene for MMD, is highly expressed in immune tissues, however, its function remains unclear. In addition, the physiological role of RNF213 gene polymorphism c.14576G > A (rs11273543...
Article
Following stress, transfer RNA (tRNA) is cleaved to generate tRNA halves (tiRNAs). These tiRNAs have been shown to repress protein translation. Angiogenin was considered the main enzyme that cleaves tRNA at its anticodon to generate 35-45 nucleotide long tiRNA halves, however, the recent reports indicate the presence of angiogenin-independent cleav...
Article
Full-text available
Contemporary paradigm of peripheral and intracranial vascular hemodynamics considers physiologic blood flow to be laminar. Transition to turbulence is considered as a driving factor for numerous diseases such as atherosclerosis, stenosis and aneurysm. Recently, turbulent flow patterns were detected in intracranial aneurysm at Reynolds number below...
Article
tiRNAs are small non-coding RNAs produced when tRNA is cleaved under stress. tRNA methylation modifications has emerged in recent years as important regulators for tRNA structural stability and sensitivity to cleavage and tiRNA generation during stress, however, the specificity and higher regulation of such a process is not fully understood. Alkbh1...
Article
Full-text available
Understanding the root causes of neuronal vulnerability to ischemia is paramount to the development of new therapies for stroke. Transient global cerebral ischemia (tGCI) leads to selective neuronal cell death in the CA1 sub-region of the hippocampus, while the neighboring CA3 sub-region is left largely intact. By studying factors pertaining to suc...
Article
Full-text available
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Data
Supplementary materials to "The hemodynamic complexities underlying transient ischemic attacks in early-stage Moyamoya disease: an exploratory CFD study"
Article
tiRNAs are small non-coding RNAs generated by angiogenin-mediated tRNA cleavage during cellular stress. Some tiRNAs were shown to be cytoprotective, while other reports indicate that the generation of tiRNAs is cytotoxic. We used rat model of focal cerebral ischemia-reperfusion (I/R) injury to study the generation and regulation of tiRNAs following...
Article
Full-text available
Moyamoya disease (MMD) is a rare cerebro-occlusive disease with unknown etiology that can cause both ischemic and hemorrhagic stroke. MMD is characterized by progressive stenosis of the terminal internal carotid artery (ICA) and development of basal brain collaterals. Early-stage MMD is known to cause hemodynamic insufficiency despite mild or moder...
Preprint
Full-text available
Contemporary paradigm of vascular hemodynamics considers normal blood flow to be pulsatile laminar flow. Transition to turbulence can cause diseases such as atherosclerosis or brain aneurysms. However, recently we demonstrated the existence of turbulence in experimental models of brain aneurysm, in the aneurysm sac as well as in the main artery. Th...
Article
Full-text available
Cranial bone defects are a major issue in thefield of neurosurgery, and improper management of such defects cancause cosmetic issues as well as more serious infections and inflammation. Several strategies exist to manage thesedefects clinically, but most rely on synthetic materials that are prone to complications; thus, a bone regenerativeapproach...
Preprint
Full-text available
Following stress, tRNA is cleaved to generate tRNA halves (tiRNAs). These stress induced small RNAs have been shown to regulate processes such as translation initiation and stem cell function. To date, angiogenin (ANG) is considered the main enzyme that cleaves tRNA at its anti-codon site to generate 35 ~ 45 nucleotide long tiRNA halves. Herein, us...
Article
Full-text available
tiRNAs are small non-coding RNAs produced when tRNA is cleaved under stress. tRNA methylation modifications has emerged in recent years as important regulators for tRNA structural stability and sensitivity to cleavage and tiRNA generation during stress, however, the specificity and higher regulation of such a process is not fully understood. Alkbh1...
Preprint
Full-text available
The genesis, growth and rupture of intracranial aneurysm (IA) are open questions in neurovascular medicine until the present moment. The complexity of aneurysm mechanobiology and pathobiology staggeringly combine intertwining biological and physical processes that are tightly connected. Recently, transition to turbulence in IA blood flow is thought...
Article
OBJECTIVE Cerebral hyperperfusion (CHP) is associated with considerable morbidity. Its pathophysiology involves disruption of the blood-brain barrier (BBB) with subsequent events such as vasogenic brain edema and ischemic and/or hemorrhagic complications. Researchers are trying to mimic the condition of CHP; however, a proper animal model is still...
Article
Full-text available
Over the past decades, tRNA was found to be a rich hub of RNA modifications such as 1-methyladenosine and 5-methycytosine modifications and others, holding more than half of all modifications occurring in RNA molecules. Moreover, tRNA was discovered to be a source of various small noncoding RNA species, such as the stress induced angiogenin cleaved...
Article
Stroke induced white matter injury can induce marked neurological deficits even after relatively small infarcts, due to the tightly packed nature of white matter tracts especially in certain areas in the brain. Many drugs which were successful in the pre-clinical trials failed in clinical trials, which was attributed in part to the focus on grey ma...
Article
Full-text available
Purpose Image-based computational fluid dynamics (CFD) is widely used to predict intracranial aneurysm wall shear stress (WSS), particularly with the goal of improving rupture risk assessment. Nevertheless, concern has been expressed over the variability of predicted WSS and inconsistent associations with rupture. Previous challenges, and studies f...
Article
Objective: The cognitive deficits of vascular dementia and the vasoocclusive state of moyamoya disease have often been mimicked with bilateral stenosis/occlusion of the common carotid artery (CCA) or internal carotid artery. However, the cerebral blood flow (CBF) declines abruptly in these models after ligation of the CCA, which differs from "chro...
Article
Full-text available
INTRODUCTION Sphingosine-1-phosphate (S1P) is a sphingolipid molecule produced by the action of sphingosine kinases (SphK) on sphingosine. It possesses various intracellular functions through its interactions with intracellular proteins or via its action on 5 G-protein-coupled cell membrane receptors. Following transient global cerebral ischemia (t...
Article
Full-text available
Intramedullary spinal cord tumors (IMSCTs) are relatively infrequent lesions with ependymomas and astrocytomas representing the most common types. Microsurgical resection is established as the treatment of choice for these challenging lesions. We reviewed the surgical outcome of 29 cases operated for IMSCTs by the same surgeon between 2009 and 2015...
Article
Full-text available
Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is the standard surgical treatment for moyamoya disease (MMD). The main potential complications of this treatment are cerebral hyperperfusion (CHP) syndrome and ischemia, and their managements are contradictory to each other. We retrospectively investigated the incidence of th...
Article
The RING finger protein 213 (RNF213) is an important susceptibility gene for moyamoya disease (MMD) and is also implicated in other types of intracranial major artery stenosis/occlusion (ICAS); however, the role of RNF213 in the development of ICAS including MMD is unclear. The constitutive expression of the RNF213 gene is relatively weak in brain...
Article
Full-text available
Spinal cord intramedullary arteriovenous malformations are rare. For patients suffering from either hemorrhage or myelopathy, surgical or endovascular interventions are indicated. However, complete eradication of the nidus is often difficult because of its intramedullary location and complex angioarchitecture. In this report, we evaluate the feasib...
Article
Full-text available
Moyamoya disease (MMD) is a rare occlusive cerebrovascular disease that mainly presents in children as cerebral ischemia. Prompt treatment with either a direct or indirect revascularization procedure is necessary for children with MMD in order to prevent repeated ischemic events. We herein present our experience with combined direct and indirect by...
Article
Full-text available
Background and purpose: Hemodynamic forces may play a role in the recanalization of coiled aneurysms. The purpose of this study was to investigate the influence of presurgical hemodynamics on the efficacy of coil embolization for basilar tip aneurysms. Methods: We identified 82 patients who underwent endovascular coil embolization for basilar ti...
Article
Objectives: We present a hemodynamic study of an intracranial aneurysm with a newly developed daughter sac during observation. We aimed to investigate the role of hemodynamics on the formation of a daughter sac. Methods: A 75-year-old male patient underwent magnetic resonance (MR) angiography, which revealed a large internal carotid artery aneur...
Conference Paper
Full-text available
Background:For many years the characterization of rupture risk for cerebral aneurysms has been a matter of great debate, with many factors being studied such as wall shear stress, aneurysm shape, location, patient characteristics, aspect ratio and others. However; to date there are no clear data on how to specify the risk of rupture for a particula...
Conference Paper
Purpose: Characterization of rupture status is a matter of great debate, and a vast arsenal of hemodynamic parameters is employed these days aiming at explaining the phenomena that might be incriminated in aneurysmal rupture. However; none of these trials could fully explain the cause of rupture in aneurysms. In this study we implemented the use of...
Article
Full-text available
Background Cavernous sinus (CS) fistulas are classified into traumatic and spontaneous. Traumatic carotid–cavernous fistulas (CCFs) are usually direct internal carotid artery (ICA) high-flow fistulas; whereas spontaneous CCFs are usually dural, low-flow fistulas and generally possess less severe symptoms than direct carotid–cavernous fistulas. Met...
Article
Full-text available
Background We describe a rare case with partially thrombosed fusiform anterior choroidal artery (AchA) aneurysm successfully treated with therapeutic occlusion of the AchA. Clinical presentation A 58-year-old man presented with transient mild hemiparesis of the right side. Magnetic resonance imaging (MRI) showed an ischemic lesion in the posterior...
Article
Full-text available
Introduction: Spinal cord arteriovenous malformations and fistulae are rare vascular lesions than can lead to myelopathy that is at many instances overlooked during diagnosing the cause of progressive myelopathy and weakness. Treatment options involve either endovascular embolization, surgical disconnection or a combination of both. This study aim...
Article
Full-text available
Background and Importance: Aneurysm formation after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass is a rare condition with only a handful of cases reported in the literature with various presentations and management strategies. Various theories have been postulated to explain such rare complication and to determine whether i...
Article
Full-text available
Giant intracranial aneurysms are rare disorders that represent only 5 % of all intracranial aneurysms; they have a wide variety of presentations including rupture, embolic effects, and mass effect symptoms that can mislead the diagnosis to tumors rather than aneurysms. Their treatment is difficult and carries higher morbidity and mortality than usu...
Article
Full-text available
Background: Traumatic carotid pseudoaneurysms are a rare cause of intractable recurrent epistaxis following a head trauma that is usually treated after a delay by days or even months. Their management includes various options, surgical or endo-vascular, depending on the clinical situation and the angio-graphic findings in the patient, with a prefer...
Article
Background: Vein of Galen aneurysmal malformations are a rare entity of vascular malformations that present themselves in neonates and infants by congestive heart failure in early days of life or later on by hydrocephalus and macrocephaly; very few reports exist on their presentation in adulthood. Case Presentation: In this case report, we review a...

Questions

Questions (5)
Question
Have anyone had their manuscripts rejected by a reviewer/editor who is clearly unqualified to review said work? recently my colleagues and I came across this more than often in Nature, Science and PNAS. With editor/review comments that are wrong on an undergraduate level. And even rebutting these comments and showing the managing editor that they are clearly wrong does not have any sway on the decision.
Any similar experiences?
Question
If the test subjects for a study that involves non-invasive routine procedures are the authors of the same study, and they declare this. Do the authors still need ethical review board approval to submit their work?
Question
How many times did you submit a paper to a journal, only to get a revision asking you to cite a particular paper or a particular author's work while it won't add any merit to your paper/discussion?
Do you think it is ethical for reviewers or editors to increase their citations by holding the decision to publish or accept at ransom?
Shouldn't the Journal have strict guidelines on when a particular paper can be asked for as a citation or not?
Should we, as researchers, start boycotting Journals that don't take action against such a behavior?
Question
I am trying to perform miRNA microarray analysis for a human cell line. Though the samples have good A260/A280 ratio (2 and above) and good RIN (most above 8) the A260/A230 ratio is low in many of the samples (as low as 0.3 in some samples).
So the question is, is it wise to proceed with these samples? can the A260/A230 ratio affect the quality of the microarray (I will use Agilent microarray chip)?
PS: The analysis will be done with a company and not in-house. Qiagen miRNeasy kit was used to extract the RNA, a DNASE treatment step was included.
Question
I am researching into hyperperfusion syndrome and prevention, specially in carotid stenting. 
Is there any evidence that a staged procedure is more beneficial than a single stage procedure in severe ICA stenosis (80% or higher)
Have you experienced cases with hyperperfusion syndrome following carotid stenting ?

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Projects

Projects (12)
Project
COVID-19 infection spreads through airborne transmission. Expiratory aerosols contain active SARS-CoV-2 RNA have varying characteristics making airborne transmission evident and significant. Computational Fluid Dynamics (CFD) simulations of infectious aerosol in different scenarios contribute to our understanding of infection control methods.
Project
In this work I investigate the cleavage of tRNA under cellular stress conditions. In this work I focus on the higher regulation of tRNA cleavage and exploring the cell and stress specificity of such process. I also explore the translational aspect of tRNA cleavage either as a disease biomarker or as therapeutic target.