In JoVE (1)
Other Publications (10)
- Proceedings of the National Academy of Sciences of the United States of America
- Journal of Cerebral Blood Flow and Metabolism : Official Journal of the International Society of Cerebral Blood Flow and Metabolism
- Neurotherapeutics : the Journal of the American Society for Experimental NeuroTherapeutics
- Neurobiology of Disease
- Molecules (Basel, Switzerland)
- Brain Research
- Journal of Neuroinflammation
- PloS One
- Experimental Neurology
- Metabolic Brain Disease
Articles by Jenna Ziebell in JoVE
Primer for Immunohistochemistry on Cryosectioned Rat Brain Tissue: Example Staining for Microglia and Neurons Megan N. Evilsizor1,2, Helen F. Ray-Jones1,3, Jonathan Lifshitz1,2,4,5, Jenna Ziebell1,2 1Department of Child Health, University of Arizona College of Medicine - Phoenix, 2 This introductory level protocol describes the reagents, equipment, and techniques required to complete immunohistochemical staining of rodent brains, using markers for microglia and neuronal elements as an example.
Other articles by Jenna Ziebell on PubMed
Ablation of D1 Dopamine Receptor-expressing Cells Generates Mice with Seizures, Dystonia, Hyperactivity, and Impaired Oral Behavior Proceedings of the National Academy of Sciences of the United States of America. Mar, 2007 | Pubmed ID: 17360497 Huntington's disease is characterized by death of striatal projection neurons. We used a Cre/Lox transgenic approach to generate an animal model in which D1 dopamine receptor (Drd1a)+ cells are progressively ablated in the postnatal brain. Striatal Drd1a, substance P, and dynorphin expression is progressively lost, whereas D2 dopamine receptor (Drd2) and enkephalin expression is up-regulated. Magnetic resonance spectroscopic analysis demonstrated early elevation of the striatal choline/creatine ratio, a finding associated with extensive reactive striatal astrogliosis. Sequential MRI demonstrated a progressive reduction in striatal volume and secondary ventricular enlargement confirmed to be due to loss of striatal cells. Mutant mice had normal gait and rotarod performance but displayed hindlimb dystonia, locomotor hyperactivity, and handling-induced electrographically verified spontaneous seizures. Ethological assessment identified an increase in rearing and impairments in the oral behaviors of sifting and chewing. In line with the limbic seizure profile, cell loss, astrogliosis, microgliosis, and down-regulated dynorphin expression were seen in the hippocampal dentate gyrus. This study specifically implicates Drd1a+ cell loss with tail suspension hindlimb dystonia, hyperactivity, and abnormal oral function. The latter may relate to the speech and swallowing disturbances and the classic sign of tongue-protrusion motor impersistence observed in Huntington's disease. In addition, the findings of this study support the notion that Drd1a and Drd2 are segregated on striatal projection neurons.
Role of CCL2 (MCP-1) in Traumatic Brain Injury (TBI): Evidence from Severe TBI Patients and CCL2-/- Mice Journal of Cerebral Blood Flow and Metabolism : Official Journal of the International Society of Cerebral Blood Flow and Metabolism. Apr, 2010 | Pubmed ID: 20029451 Cerebral inflammation involves molecular cascades contributing to progressive damage after traumatic brain injury (TBI). The chemokine CC ligand-2 (CCL2) (formerly monocyte chemoattractant protein-1, MCP-1) is implicated in macrophage recruitment into damaged parenchyma after TBI. This study analyzed the presence of CCL2 in human TBI, and further investigated the role of CCL2 in physiological and cellular mechanisms of secondary brain damage after TBI. Sustained elevation of CCL2 was detected in the cerebrospinal fluid (CSF) of severe TBI patients for 10 days after trauma, and in cortical homogenates of C57Bl/6 mice, peaking at 4 to 12 h after closed head injury (CHI). Neurological outcome, lesion volume, macrophage/microglia infiltration, astrogliosis, and the cerebral cytokine network were thus examined in CCL2-deficient (-/-) mice subjected to CHI. We found that CCL2-/- mice showed altered production of multiple cytokines acutely (2 to 24 h); however, this did not affect lesion size or cell death within the first week after CHI. In contrast, by 2 and 4 weeks, a delayed reduction in lesion volume, macrophage accumulation, and astrogliosis were observed in the injured cortex and ipsilateral thalamus of CCL2-/- mice, corresponding to improved functional recovery as compared with wild-type mice after CHI. Our findings confirm the significant role of CCL2 in mediating post-traumatic secondary brain damage.
Involvement of Pro- and Anti-inflammatory Cytokines and Chemokines in the Pathophysiology of Traumatic Brain Injury Neurotherapeutics : the Journal of the American Society for Experimental NeuroTherapeutics. Jan, 2010 | Pubmed ID: 20129494 Despite dramatic improvements in the management of traumatic brain injury (TBI), to date there is no effective treatment available to patients, and morbidity and mortality remain high. The damage to the brain occurs in two phases, the initial primary phase being the injury itself, which is irreversible and amenable only to preventive measures to minimize the extent of damage, followed by an ongoing secondary phase, which begins at the time of injury and continues in the ensuing days to weeks. This delayed phase leads to a variety of physiological, cellular, and molecular responses aimed at restoring the homeostasis of the damaged tissue, which, if not controlled, will lead to secondary insults. The development of secondary brain injury represents a window of opportunity in which pharmaceutical compounds with neuroprotective properties could be administered. To establish effective treatments for TBI victims, it is imperative that the complex molecular cascades contributing to secondary injury be fully elucidated. One pathway known to be activated in response to TBI is cellular and humoral inflammation. Neuroinflammation within the injured brain has long been considered to intensify the damage sustained following TBI. However, the accumulated findings from years of clinical and experimental research support the notion that the action of inflammation may differ in the acute and delayed phase after TBI, and that maintaining limited inflammation is essential for repair. This review addresses the role of several cytokines and chemokines following focal and diffuse TBI, as well as the controversies around the use of therapeutic anti-inflammatory treatments versus genetic deletion of cytokine expression.
Deficiency of the Chemokine Receptor CXCR2 Attenuates Neutrophil Infiltration and Cortical Damage Following Closed Head Injury Neurobiology of Disease. Nov, 2010 | Pubmed ID: 20621186 The contribution of infiltrated neutrophils to secondary damage following traumatic brain injury remains controversial. Chemokines that regulate neutrophil migration by signaling through the CXCR2 receptor are markedly elevated by brain injury and are associated with the propagation of secondary damage. This study thus investigated the function of CXCR2 in posttraumatic inflammation and secondary degeneration by examining Cxcr2-deficient (Cxcr2(-/-)) mice over 14 days following closed head injury (CHI). We demonstrate a significant attenuation of neutrophil infiltration in Cxcr2(-/-) mice at 12 hours and 7 days after CHI, despite increased levels of CXC neutrophil-attracting chemokines in the lesioned cortex. This coincides with reduced tissue damage, neuronal loss, and cell death in Cxcr2(-/-) mice compared to wild-type controls, with heterozygotes showing intermediate responses. In contrast, blood-brain barrier permeability and functional recovery did not appear to be affected by Cxcr2 deletion. This study highlights the deleterious contribution of neutrophils to posttraumatic neurodegeneration and demonstrates the importance of CXC chemokine signaling in this process. Therefore, CXCR2 antagonistic therapeutics currently in development for other inflammatory conditions may also be of benefit in posttraumatic neuroinflammation.
Kinin Receptor Antagonists As Potential Neuroprotective Agents in Central Nervous System Injury Molecules (Basel, Switzerland). Sep, 2010 | Pubmed ID: 20877247 Injury to the central nervous system initiates complex physiological, cellular and molecular processes that can result in neuronal cell death. Of interest to this review is the activation of the kinin family of neuropeptides, in particular bradykinin and substance P. These neuropeptides are known to have a potent pro-inflammatory role and can initiate neurogenic inflammation resulting in vasodilation, plasma extravasation and the subsequent development of edema. As inflammation and edema play an integral role in the progressive secondary injury that causes neurological deficits, this review critically examines kinin receptor antagonists as a potential neuroprotective intervention for acute brain injury, and more specifically, traumatic brain and spinal cord injury and stroke.
Attenuated Neurological Deficit, Cell Death and Lesion Volume in Fas-mutant Mice is Associated with Altered Neuroinflammation Following Traumatic Brain Injury Brain Research. Sep, 2011 | Pubmed ID: 21871613 Progressive neurodegeneration following traumatic brain injury (TBI) involves the Fas and TNF-receptor1 protein systems which have been implicated in mediating delayed cell death. In this study, we used two approaches to assess whether inhibition of these pathways reduced secondary brain damage and neurological deficits after TBI. Firstly, we investigated whether the expression of non-functional Fas in lpr mice subjected to TBI altered tissue damage and neurological outcome. Compared to wild-type, lpr mice showed improved neurological deficit (p=0.0009), decreased lesion volume (p=0.017), number of TUNEL+ cells (p=0.011) and caspase-3+ cells (p=0.007). Changes in cellular inflammation and cytokine production were also compared between mouse strains. Accumulation of macrophages/microglia occurred earlier in lpr mice, likely due to enhanced production of the chemotactic mediators IL-12(p40) and MCP-1 (p
Rod Microglia: Elongation, Alignment, and Coupling to Form Trains Across the Somatosensory Cortex After Experimental Diffuse Brain Injury Journal of Neuroinflammation. 2012 | Pubmed ID: 23111107 Since their discovery, the morphology of microglia has been interpreted to mirror their function, with ramified microglia constantly surveying the micro-environment and rapidly activating when changes occur. In 1899, Franz Nissl discovered what we now recognize as a distinct microglial activation state, microglial rod cells (Stäbchenzellen), which he observed adjacent to neurons. These rod-shaped microglia are typically found in human autopsy cases of paralysis of the insane, a disease of the pre-penicillin era, and best known today from HIV-1-infected brains. Microglial rod cells have been implicated in cortical 'synaptic stripping' but their exact role has remained unclear. This is due at least in part to a scarcity of experimental models. Now we have noted these rod microglia after experimental diffuse brain injury in brain regions that have an associated sensory sensitivity. Here, we describe the time course, location, and surrounding architecture associated with rod microglia following experimental diffuse traumatic brain injury (TBI).
Rod Microglia: a Morphological Definition PloS One. 2014 | Pubmed ID: 24830807 Brain microglial morphology relates to function, with ramified microglia surveying the micro-environment and amoeboid microglia engulfing debris. One subgroup of microglia, rod microglia, have been observed in a number of pathological conditions, however neither a function nor specific morphology has been defined. Historically, rod microglia have been described intermittently as cells with a sausage-shaped soma and long, thin processes, which align adjacent to neurons. More recently, our group has described rod microglia aligning end-to-end with one another to form trains adjacent to neuronal processes. Confusion in the literature regarding rod microglia arises from some reports referring to the sausage-shaped cell body, while ignoring the spatial distribution of processes. Here, we systematically define the morphological characteristics of rod microglia that form after diffuse brain injury in the rat, which differ morphologically from the spurious rod microglia found in uninjured sham. Rod microglia in the diffuse-injured rat brain show a ratio of 1.79 ± 0.03 cell length:cell width at day 1 post-injury, which increases to 3.35 ± 0.05 at day 7, compared to sham (1.17 ± 0.02). The soma length:width differs only at day 7 post-injury (2.92 ± 0.07 length:width), compared to sham (2.49 ± 0.05). Further analysis indicated that rod microglia may not elongate in cell length but rather narrow in cell width, and retract planar (side) processes. These morphological characteristics serve as a tool for distinguishing rod microglia from other morphologies. The function of rod microglia remains enigmatic; based on morphology we propose origins and functions for rod microglia after acute neurological insult, which may provide biomarkers or therapeutic targets.
Commentary on Kamper Et. Al., Juvenile Traumatic Brain Injury Evolves into a Chronic Brain Disorder: The Challenges in Longitudinal Studies of Juvenile Traumatic Brain Injury Experimental Neurology. Nov, 2014 | Pubmed ID: 24931226 Juvenile traumatic brain injury (TBI) leaves survivors facing a potential lifetime of cognitive, somatic and emotional symptoms. A recent study published in Experimental Neurology (Kamper et al., 2013) explored the chronic consequences of focal brain injury induced in the juvenile animal, extending their previous observations out to 6months post-injury. The results demonstrate transient, persistent, and late onset behavioral dysfunction, which are associated with subtle evidence for enduring histopathology. In line with investigations about chronic traumatic encephalopathy from brain injury initiated in the adult, juvenile TBI establishes signs of a chronic brain disorder, with unique considerations relative to ongoing developmental processes. This commentary discusses the challenges in evaluating aging with injury in the juvenile population, the current methods of juvenile TBI, and what can be anticipated for the future of the field.
Microglia: Dismantling and Rebuilding Circuits After Acute Neurological Injury Metabolic Brain Disease. Apr, 2015 | Pubmed ID: 24733573 The brain is comprised of neurons and its support system including astrocytes, glial cells and microglia, thereby forming neurovascular units. Neurons require support from glial cells to establish and maintain functional circuits, but microglia are often overlooked. Microglia function as the immune cell of the central nervous system, acting to monitor the microenvironment for changes in signaling, pathogens and injury. More recently, other functional roles for microglia within the healthy brain have been identified, including regulating synapse formation, elimination and function. This review aims to highlight and discuss these alternate microglial roles in the healthy and in contrast, diseased brain with a focus on two acute neurological diseases, traumatic brain injury and epilepsy. In these conditions, microglial roles in synaptic stripping and stabilization as part of neuronal:glial interactions may position them as mediators of the transition between injury-induced circuit dismantling and subsequent reorganization. Increased understanding of microglia roles could identify therapeutic targets to mitigate the consequences of neurological disease.