Publications by authors named "Mohammed Shaker"

Valproic acid (VPA) is an effective and widely used anti-seizure medication but is teratogenic when used during pregnancy, affecting brain and spinal cord development for reasons that remain largely unclear. Here we designed a genetic recombinase-based SOX10 reporter system in human pluripotent stem cells that enables tracking and lineage tracing of Neural Crest cells (NCCs) in a human organoid model of the developing neural tube. We found that VPA induces extensive cellular senescence and promotes mesenchymal differentiation of human NCCs.

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Why individuals with Down syndrome (DS) are more susceptible to SARS-CoV-2-induced neuropathology remains elusive. Choroid plexus (ChP) plays critical roles in barrier function and immune response modulation and expresses the ACE2 receptor and the chromosome 21-encoded TMPRSS2 protease, suggesting its substantial role in establishing SARS-CoV-2 infection in the brain. To explore this, we established brain organoids from DS and isogenic euploid iPSC that consist of a core of functional cortical neurons surrounded by a functional ChP-like epithelium (ChPCOs).

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Stem cells and the cells they produce are unique because they vary from one cell to another. Traditional methods of studying cells often overlook these differences. However, the development of new technologies for studying individual cells has greatly changed biological research in recent years.

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In response to the scarcity of advanced in vitro models dedicated to human CNS white matter research, we present a protocol to generate neuroectoderm-derived embedding-free human brain organoids enriched with oligodendrocytes. We describe steps for neuroectoderm differentiation, development of neural spheroids, and their transferal to Matrigel. We then detail procedures for the development, maturation, and application of oligodendrocyte-enriched brain organoids.

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Article Synopsis
  • In vertebrates, the central nervous system develops from the neural tube through a process called neurulation, and defects in this process can lead to neural tube defects (NTDs).
  • Recent research created human spinal cord organoids (hSCOs) to study neurulation and found that valproic acid (VPA) can induce defects in these organoids, affecting cell-cell junctional genes and proteins.
  • The study also showed that VPA-treated mouse embryos had similar developmental issues, highlighting that hSCOs are useful for exploring the underlying molecular mechanisms of human neurulation and NTDs.
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Brain organoids are three-dimensional models of the developing human brain and provide a compelling, cutting-edge platform for disease modeling and large-scale genomic and drug screening. Due to the self-organizing nature of cells in brain organoids and the growing range of available protocols for their generation, issues with heterogeneity and variability between organoids have been identified. In this protocol paper, we describe a robust and replicable protocol that largely overcomes these issues and generates cortical organoids from neuroectodermal progenitors within 1 month, and that can be maintained for more than 1 year.

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Article Synopsis
  • * The hSCOs demonstrate key features of spinal cord development, including proper cellular differentiation into spinal-cord neurons and glial cells, as well as the ability to form mature synapses.
  • * The organoids can be used to test antiepileptic drugs for potential neural-tube defects and offer a valuable model for understanding spinal cord development and related disorders.
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Neural epidermal growth factor-like like 2 (NELL2) is a cytoplasmic and secreted glycosylated protein with six epidermal growth factor-like domains. In animal models, NELL2 is predominantly expressed in neural tissues where it regulates neuronal differentiation, polarization, and axon guidance, but little is known about the role of NELL2 in human brain development. In this study, we show that rostral neural stem cells (rNSC) derived from human-induced pluripotent stem cell (hiPSC) exhibit particularly strong expression and that NELL2 protein is enriched at the apical side of neural rosettes in hiPSC-derived brain organoids.

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In this paper, we describe the generation and validation of human induced pluripotent stem cell (hiPSC) lines from peripheral blood mononuclear cells (PBMCs) from 6 epilepsy patients using a non-integrative Sendai virus vector. These human cellular models will enable patient-specific drug screening to improve outcomes for individuals with this disorder.

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Epilepsy is a common neurological disorder characterized by seizures. Unfortunately, 30-40% of all epilepsy patients are resistant to at least two or more anti-seizure medications. Attempts to treat these patients and prevent further seizures necessitates multiple drug trials for the patient.

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Alzheimer's disease (AD) is a progressive neurodegenerative disorder that leads to dementia and behavioral changes. Extracellular deposition of amyloid plaques (Aβ) and intracellular deposition of neurofibrillary tangles in neurons are the major pathogenicities of AD. However, drugs targeting these therapeutic targets are not effective.

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Ataxia-telangiectasia (A-T) is a genetic disorder caused by the lack of functional ATM kinase. A-T is characterized by chronic inflammation, neurodegeneration and premature ageing features that are associated with increased genome instability, nuclear shape alterations, micronuclei accumulation, neuronal defects and premature entry into cellular senescence. The causal relationship between the detrimental inflammatory signature and the neurological deficiencies of A-T remains elusive.

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Aging is a major risk factor for many neurodegenerative diseases. Klotho (KL) is a glycosylated transmembrane protein that is expressed in the choroid plexus and neurons of the brain. KL exerts potent anti-aging effects on multiple cell types in the body but its role in human brain cells remains largely unclear.

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Aims: During vertebrate development, the posterior end of the embryo progressively elongates in a head-to-tail direction to form the body plan. Recent lineage tracing experiments revealed that bi-potent progenitors, called neuromesodermal progenitors (NMPs), produce caudal neural and mesodermal tissues during axial elongation. However, their precise location and contribution to spinal cord development remain elusive.

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Neuromesodermal progenitors (NMPs) constitute a bipotent cell population that generates a wide variety of trunk cell and tissue types during embryonic development. Derivatives of NMPs include both mesodermal lineage cells such as muscles and vertebral bones, and neural lineage cells such as neural crests and central nervous system neurons. Such diverse lineage potential combined with a limited capacity for self-renewal, which persists during axial elongation, demonstrates that NMPs are a major source of trunk tissues.

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Human stem cell derived brain organoids are increasingly gaining attention as an ideal model system for investigating neurological diseases, particularly those that involve myelination defects. However, current protocols for generating brain organoids with sufficiently mature oligodendrocytes that deposit myelin on endogenously produced neurons are lengthy and complicated. Taking advantage of a human pluripotent stem cell line that reports on SOX10 expression, we developed a protocol that involves a 42 day exposure of neuroectoderm-derived organoids to a cocktail of growth factors and small molecules that collectively foster oligodendrocyte specification and survival.

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Mammalian embryos exhibit a transition from head morphogenesis to trunk elongation to meet the demand of axial elongation. The caudal neural tube (NT) is formed with neural progenitors (NPCs) derived from neuromesodermal progenitors localized at the tail tip. However, the molecular and cellular basis of elongating NT morphogenesis is yet elusive.

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Background: One of the most widespread cancer-associated death worldwide is Hepatocellular carcinoma. Concerning hepatic malignant tumor staging system known as Barcelona clinic of liver cancer, a superior curative response could be carried out by combined techniques [radiofrequency ablation (RFA) and transarterial chemoembolization (TACE)] for stage B comparing with TACE alone as palliative monotherapy.

Objectives: To discuss the merging effect of RFA followed by TACE and vice versa on objective response, overall survival, local recurrence and tumor-free survival.

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Background: Early detection of hepatocellular carcinoma is very important in the treatment which is feasible. Alpha-fetoprotein plus ultrasound in surveillance programs is controversial. GP73 is a protein.

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Neural stem cells (NSCs) in the embryonic neocortex have the potential to generate a well-organized laminar architecture of the cerebral cortex through precise regulation of the proliferation, differentiation, and migration of neural cells. NSCs can be isolated in vitro and expanded as cell clusters, called neurospheres, which are primarily related to the proliferation ability of NSCs. Conversely, the tissue-organizing properties of NSCs via regulated differentiation and migration of the cells are not well understood.

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Focal adhesion pathway is one of the key molecular pathways affected by suboptimal culture conditions during embryonic development. The epidermal growth factor (EGF) and hyaluronic acid (HA) are believed to be involved in the focal adhesion pathway function by regulating the adherence of the molecules to the extracellular matrix. However, regulatory and molecular mechanisms through which the EGF and HA could influence the embryo development is not clear.

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Article Synopsis
  • Decellularization offers ECM scaffolds for tissue regeneration but often weakens the structure, limiting its use in soft organs.
  • The CASPER technique enhances decellularization by using hydrogels to protect ECM integrity, preserving its complex structures and functions.
  • CASPERized tissues can be recellularized and successfully implanted without causing inflammation, making them suitable for studying cell-ECM interactions and potential organ transplantation.
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Evaluation of the efficacy and safety of sofosbuvir/daclatasvir/ribavirin (SOF/DCV/RBV) in treating non-sustained virological responders (non-SVR12) to prior sofosbuvir-based therapy, in absence of RAS testing in mass treatment, and determination of the optimal timing to start re-treatment. Real-life prospective observational study included prior non-responders to 24-weeks SOF-RBV (n = 679, 67%) or 12-weeks SOF- RBV- PEG (n = 335, 33%). Patients were re-treated with daily SOF/DCV/RBV for 12 (n = 270) or 24 weeks (n = 744).

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The inability of neurons to undergo mitosis renders damage to the central or peripheral nervous system. Neural stem cell therapy could provide a path for treating the neurodegenerative diseases. However, reliable and simple tools for the developing and testing neural stem cell therapy are still required.

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Context: Monoclonal antibodies are being investigated for chronic pain to overcome the shortcomings of current treatment options.

Objective: To provide a practical overview of monoclonal antibodies in clinical development for use in chronic pain conditions, with a focus on mechanisms of action and relevance to specific classes.

Methods: Qualitative review using a systematic strategy to search for randomized controlled trials, systematic and nonsystematic (narrative) reviews, observational studies, nonclinical studies, and case reports for inclusion.

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