National Institute of Neurological Disorders and Stroke (NINDS)

The Mughal Laboratory (The Neurovascular Research Unit) studies the neurovascular coupling mechanisms involved in regulation of blood flow in the brain and clearance of metabolic by-products. Along with providing the basic understanding of these mechanisms in physiology, the research also extends to the vascular cognitive impairment and dementia (VCID) including stroke and CADASIL. By using pre-clinical models and cutting-edge imaging approaches, the Mughal laboratory provides a thorough understanding of different neurovascular mechanisms along with the contributions of different vascular compartments (arteries—capillaries— veins) with the aim to extend this knowledge from physiology to the disease models.

The research program is supported by multiple on-going projects. Students will have the option to work on any project in the lab, and to take it in new directions. 
 

Research keywords: Neurovascular, Ion channels, Calcium signaling, Blood flow in the brain
 

One of the major obstacles to effectively treating central nervous system (CNS) tumors is the integrity of the blood-brain barrier (BBB). The BBB prevents systemic drug delivery from reaching the brain and brain tumor tissue. While previous studies have mainly focused on circumventing the BBB, very few agents or mechanisms have been explored that modulate the tumor microenvironment to enhance effective therapies for malignant brain tumors. Our studies focus on understanding the heterogeneity of BBB permeability amongst malignant tumor cells and the role of the supportive BBB in tumor growth. Our collaborative laboratory and clinical investigations center around BBB biology, cancer biology, pharmacokinetics and pharmacodynamics related to optimal CNS drug delivery.

Using a clinical/translational approach, we aim to:

1) Evaluate the efficacy of targeted tumor and BBB directed therapy

2) Define the mechanisms that drive differences in neuropharmacokinetics of agents to the CNS

3) Identify exquisite parameters via neuro-imaging of CNS permeability amongst malignant brain tumors.

Our overall goal is to enhance our understanding of the heterogeneity of blood-brain barrier permeability among tumor cells and develop mechanism-based therapeutic interventions to treat affected brain tumor patients at the NIH Clinical Center. We use a combination of cell biology, molecular biology, imaging, pharmacokinetics and animal tumor models.

Multisensory learning helps an individual learn through more than one sense. However, the underlying neural mechanism is unclear. In this study we aim to pursue this question in a spatial learning regime. We will focus on the medial entorhinal cortex (MEC), which plays a critical role in spatial learning and the dysfunction of which is closely related to Alzheimer’s disease. We will record neural dynamics of the MEC using two-photon imaging approach when mice navigate in virtual environments, in which multisensory spatial information will be precisely delivered. The goal of the project is to deeply understand how the neural response of the MEC contributes to multisensory learning.

A balance between neuronal excitation and inhibition is crucial for normal brain physiology; upsetting this balance underlies various brain pathologies. To shed light on the molecular underpinnings of this regulation at the synapse level, this project will investigate the dynamics of glutamate- and GABA-A synapses and receptors in CA1 hippocampus under baseline conditions and in response to synapse potentiation. Specifically, using structural, functional and imaging approaches we will study both, spiny glutamatergic and aspiny GABA-ergic CA1 synapses and associated receptor complexes (AMPA-type glutamate and GABA-A) and how these change at the synapse- and receptor levels in response to LTP (long-term potentiation) induction. Our aim will be to monitor changes of glutamatergic and GABAergic synapses and receptors at pyramidal neurons (glutamate) and/or parvalbumin-positive (PV+) interneurons at various points after LTP induction. We will monitor changes in synapse size and receptor composition using advanced imaging and electrophysiological approaches.

Inherited neurological disorders are disabling, progressive, often fatal conditions, representing an enormous unmet medical need with devastating impacts on affected families, the healthcare system, and the economy. There are no cures and the limited therapies available treat symptoms without addressing the underlying disease.

Next-generation sequencing has facilitated a molecular diagnosis for many inherited neurological disorders, such as mitochondrial diseases and other neuromuscular diseases, which are the focus of this research. The development of targeted therapies requires detailed laboratory investigation of molecular and mutational mechanisms, and a systematic evaluation of well-chosen agents as well as gene and transcript directed strategies using standardized experimental systems. Our research is focusing on understanding the molecular pathogenesis of childhood onset inherited neurological diseases, such as mitochondrial disease and other neuromuscular diseases to develop targeted therapies.

Using a translational approach, we aim to
1. understand the clinical course of patients in relation to the underlying disease mechanism
2. delineate the mutational and molecular mechanisms of the molecular defect in the appropriate cell types by developing model systems such as induced neuronal progenitor cells (in vitro) and zebrafish (in vivo)
3. improve the treatment options for patients by developing novel therapies that are directed at these mechanisms, including directly at the genetic mutation or resulting transcript.

We use a combination of exome sequencing, genome sequencing, and other omics technologies to identify novel disease genes and disease mechanisms. By functional evaluation in vitro (induced neuronal progenitor cells) and in vivo (zebrafish) we confirm pathogenicity and uncover molecular mechanisms of disease. To address the mutational mechanisms, we use gene transfer, splice modulation, allele silencing and CRISPR/cas systems.

The human brain is astonishing: it is the source of our thoughts, actions, memories, perceptions and emotions. It confers on us the abilities that make us human, while simultaneously making each of us unique. Through deepened knowledge and understanding of how human brain works, we will comprehend ourselves better and treat brain diseases more incisively. Over recent years, neuroscience has advanced to the level that we can envision spanning molecules, cells and neuronal circuits in action. In particular, there is an emerging view that subtle aspects of presynaptic dysfunction are implicated in an increasing number of brain disorders such as neurological and neurodegenerative diseases.

We are particularly interested in exocytosis, a process of vital importance for neuronal cells that is controlled by a set of both positive and negative regulators. While promotors of exocytosis are well studied, negative regulators are poorly understood. We discovered that a small SNARE protein amisyn (STXBP6) acts as a vertebrate-specific competitor of synaptobrevin-2, a key player in exocytosis. Amisyn contains an N-terminal pleckstrin homology domain that mediates its transient association with the plasma membrane by binding to phospholipid PI(4,5)P2. Both the pleckstrin homology and SNARE domains are needed to inhibit exocytosis. Of note, amisyn is poorly studied despite several studies have emphasized its importance for exocytosis and reported the occurrence of amisyn mutations in autism, diabetes and cancer.

This PhD project aims to study mechanisms of exocytosis with a focus on amisyn. The candidate will study how lack or impaired function of amisyn modulates exocytosis, synaptic transmission and behavior. We have generated a mouse model without amisyn to be employed for these studies. In addition, our collaborative team has expertise in a wide variety of interdisciplinary techniques to support and facilitate the proposed PhD project, such as biochemical, (electro)physiologal and life confocal microscopy techniques.

Our lab seeks to explore the neural mechanisms underlying cognitive function by exploiting the unique investigative opportunities provided by intracranial electrical recordings during neurosurgical procedures. Using recordings captured from epilepsy patients implanted with subdural and depth electrodes, we investigate the activation of cortical networks during memory encoding and recall. And using recordings captured during implantation of deep brain stimulators, we investigate the role of the basal ganglia in learning and decision-making.

Retroviral sequences remain dormant in the human genome and occupy nearly 7-8% of the genomic sequence. We have shown that one of these viruses termed HERV-K (HML-2) is activated in patients with amyotrophic lateral sclerosis (ALS), and transgenic animals that express the envelope protein of HERV-K develop ALS like symptoms. Hence, we are now using a wide variety of structural biology and virology tools to determine the mechanism by which its expression is regulated and causes neurotoxicity to motor neurons. 

Understand the disease mechanisms and potential treatments for hereditary motor neuron diseases such as spinal muscular atrophy and polyglutamine expansion diseases such as Huntington's disease.