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Sharifi KA, Farzad F, Soldozy S, DeWitt MR, Price RJ, Sheehan J, Kalani MYS, Tvrdik P. Exploring the dynamics of adult Axin2 cell lineage integration into dentate gyrus granule neurons. Front Neurosci 2024; 18:1353142. [PMID: 38449734 PMCID: PMC10915230 DOI: 10.3389/fnins.2024.1353142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/31/2024] [Indexed: 03/08/2024] Open
Abstract
The Wnt pathway plays critical roles in neurogenesis. The expression of Axin2 is induced by Wnt/β-catenin signaling, making this gene a reliable indicator of canonical Wnt activity. We employed pulse-chase genetic lineage tracing with the Axin2-CreERT2 allele to follow the fate of Axin2+ lineage in the adult hippocampal formation. We found Axin2 expressed in astrocytes, neurons and endothelial cells, as well as in the choroid plexus epithelia. Simultaneously with the induction of Axin2 fate mapping by tamoxifen, we marked the dividing cells with 5-ethynyl-2'-deoxyuridine (EdU). Tamoxifen induction led to a significant increase in labeled dentate gyrus granule cells three months later. However, none of these neurons showed any EdU signal. Conversely, six months after the pulse-chase labeling with tamoxifen/EdU, we identified granule neurons that were positive for both EdU and tdTomato lineage tracer in each animal. Our data indicates that Axin2 is expressed at multiple stages of adult granule neuron differentiation. Furthermore, these findings suggest that the integration process of adult-born neurons from specific cell lineages may require more time than previously thought.
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Affiliation(s)
- Khadijeh A Sharifi
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States
| | - Faraz Farzad
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
- Department of Neurosurgery, Westchester Medical Center and New York Medical College, Valhalla, NY, United States
| | - Matthew R DeWitt
- Department of Focused Ultrasound Cancer Immunotherapy Center, University of Virginia, Charlottesville, VA, United States
| | - Richard J Price
- Biomedical Engineering, University of Virginia, Charlottesville, VA, United States
| | - Jason Sheehan
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States
- School of Medicine, St. John's Neuroscience Institute, University of Oklahoma, Tulsa, OK, United States
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States
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Fisher DG, Sharifi KA, Shah IM, Gorick CM, Breza VR, Debski AC, Hoch MR, Cruz T, Samuels JD, Sheehan JP, Schlesinger D, Moore D, Lukens JR, Miller GW, Tvrdik P, Price RJ. Focused Ultrasound Blood-Brain Barrier Opening Arrests the Growth and Formation of Cerebral Cavernous Malformations. bioRxiv 2024:2024.01.31.577810. [PMID: 38352349 PMCID: PMC10862920 DOI: 10.1101/2024.01.31.577810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
BACKGROUND Cerebral cavernous malformations (CCM) are vascular lesions within the central nervous system, consisting of dilated and hemorrhage-prone capillaries. CCMs can cause debilitating neurological symptoms, and surgical excision or stereotactic radiosurgery are the only current treatment options. Meanwhile, transient blood-brain barrier opening (BBBO) with focused ultrasound (FUS) and microbubbles is now understood to exert potentially beneficial bioeffects, such as stimulation of neurogenesis and clearance of amyloid-β. Here, we tested whether FUS BBBO could be deployed therapeutically to control CCM formation and progression in a clinically-representative murine model. METHODS CCMs were induced in mice by postnatal, endothelial-specific Krit1 ablation. FUS was applied for BBBO with fixed peak-negative pressures (PNPs; 0.2-0.6 MPa) or passive cavitation detection-modulated PNPs. Magnetic resonance imaging (MRI) was used to target FUS treatments, evaluate safety, and measure longitudinal changes in CCM growth after BBBO. RESULTS FUS BBBO elicited gadolinium accumulation primarily at the perilesional boundaries of CCMs, rather than lesion cores. Passive cavitation detection and gadolinium contrast enhancement were comparable in CCM and wild-type mice, indicating that Krit1 ablation does not confer differential sensitivity to FUS BBBO. Acutely, CCMs exposed to FUS BBBO remained structurally stable, with no signs of hemorrhage. Longitudinal MRI revealed that FUS BBBO halted the growth of 94% of CCMs treated in the study. At 1 month, FUS BBBO-treated lesions lost, on average, 9% of their pre-sonication volume. In contrast, non-sonicated control lesions grew to 670% of their initial volume. Lesion control with FUS BBBO was accompanied by a marked reduction in the area and mesenchymal appearance of Krit mutant endothelium. Strikingly, in mice receiving multiple BBBO treatments with fixed PNPs, de novo CCM formation was significantly reduced by 81%. Mock treatment plans on MRIs of patients with surgically inaccessible lesions revealed their lesions are amenable to FUS BBBO with current clinical technology. CONCLUSIONS Our results establish FUS BBBO as a novel, non-invasive modality that can safely arrest murine CCM growth and prevent their de novo formation. As an incisionless, MR image-guided therapy with the ability to target eloquent brain locations, FUS BBBO offers an unparalleled potential to revolutionize the therapeutic experience and enhance the accessibility of treatments for CCM patients.
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Affiliation(s)
- Delaney G Fisher
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Khadijeh A Sharifi
- Department of Neuroscience, University of Virginia, Charlottesville, VA
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA
| | - Ishaan M Shah
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Catherine M Gorick
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Victoria R Breza
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Anna C Debski
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Matthew R Hoch
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Tanya Cruz
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Joshua D Samuels
- Department of Neuroscience, University of Virginia, Charlottesville, VA
| | - Jason P Sheehan
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA
| | - David Schlesinger
- Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA
| | - David Moore
- Focused Ultrasound Foundation, Charlottesville, VA
| | - John R Lukens
- Department of Neuroscience, University of Virginia, Charlottesville, VA
| | - G Wilson Miller
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
- Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, VA
| | - Petr Tvrdik
- Department of Neuroscience, University of Virginia, Charlottesville, VA
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA
| | - Richard J Price
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
- Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, VA
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Sharifi KA, Farzad F, Soldozy S, Price RJ, Kalani MYS, Tvrdik P. Dynamics of Adult Axin2 Cell Lineage Integration in Granule Neurons of the Dentate Gyrus. bioRxiv 2023:2023.12.09.570930. [PMID: 38106115 PMCID: PMC10723478 DOI: 10.1101/2023.12.09.570930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The Wnt pathway plays critical roles in neurogenesis. The expression of Axin2 is induced by Wnt/β-catenin signaling, making this gene a sensitive indicator of canonical Wnt activity. We employed pulse-chase genetic lineage tracing with the Axin2-CreERT2 allele to follow the fate of Axin2 -positive cells in the adult hippocampal formation. We found Axin2 expressed in astrocytes, neurons and endothelial cells, as well as in the choroid plexus epithelia. Simultaneously with tamoxifen induction of Axin2 fate mapping, the dividing cells were marked with 5-ethynyl-2'-deoxyuridine (EdU). Tamoxifen induction resulted in significant increase of dentate gyrus granule cells three months later; however, none of these neurons contained EdU signal. Conversely, six months after the tamoxifen/EdU pulse-chase labeling, EdU-positive granule neurons were identified in each animal. Our data imply that Axin2 is expressed at several different stages of adult granule neuron differentiation and suggest that the process of integration of the adult-born neurons from certain cell lineages may take longer than previously thought.
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Sokolowski JD, Soldozy S, Sharifi KA, Norat P, Kearns KN, Liu L, Williams AM, Yağmurlu K, Mastorakos P, Miller GW, Kalani MYS, Park MS, Kellogg RT, Tvrdik P. Preclinical models of middle cerebral artery occlusion: new imaging approaches to a classic technique. Front Neurol 2023; 14:1170675. [PMID: 37409019 PMCID: PMC10318149 DOI: 10.3389/fneur.2023.1170675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 05/30/2023] [Indexed: 07/07/2023] Open
Abstract
Stroke remains a major burden on patients, families, and healthcare professionals, despite major advances in prevention, acute treatment, and rehabilitation. Preclinical basic research can help to better define mechanisms contributing to stroke pathology, and identify therapeutic interventions that can decrease ischemic injury and improve outcomes. Animal models play an essential role in this process, and mouse models are particularly well-suited due to their genetic accessibility and relatively low cost. Here, we review the focal cerebral ischemia models with an emphasis on the middle cerebral artery occlusion technique, a "gold standard" in surgical ischemic stroke models. Also, we highlight several histologic, genetic, and in vivo imaging approaches, including mouse stroke MRI techniques, that have the potential to enhance the rigor of preclinical stroke evaluation. Together, these efforts will pave the way for clinical interventions that can mitigate the negative impact of this devastating disease.
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Affiliation(s)
- Jennifer D. Sokolowski
- Department of Neurological Surgery, University of Virginia, Charlottesville, VA, United States
| | - Sauson Soldozy
- Department of Neurological Surgery, Westchester Medical Center, Valhalla, NY, United States
| | - Khadijeh A. Sharifi
- Department of Neurological Surgery, University of Virginia, Charlottesville, VA, United States
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States
| | - Pedro Norat
- Department of Neurological Surgery, University of Virginia, Charlottesville, VA, United States
| | - Kathryn N. Kearns
- Department of Neurological Surgery, University of Virginia, Charlottesville, VA, United States
| | - Lei Liu
- Department of Neurological Surgery and Neuroscience, Northwestern University, Chicago, IL, United States
| | - Ashley M. Williams
- School of Medicine, Morsani College of Medicine, Tampa, FL, United States
| | - Kaan Yağmurlu
- Department of Neurological Surgery, University of Tennessee, Memphis, TN, United States
| | - Panagiotis Mastorakos
- Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - G. Wilson Miller
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States
| | - M. Yashar S. Kalani
- Department of Neurological Surgery, St. John's Neuroscience Institute, Tulsa, OK, United States
| | - Min S. Park
- Department of Neurological Surgery, University of Virginia, Charlottesville, VA, United States
| | - Ryan T. Kellogg
- Department of Neurological Surgery, University of Virginia, Charlottesville, VA, United States
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia, Charlottesville, VA, United States
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States
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Fisher DG, Sharifi KA, Ulutas EZ, Kumar JS, Kalani MYS, Miller GW, Price RJ, Tvrdik P. Magnetic Resonance Imaging of Mouse Cerebral Cavernomas Reveal Differential Lesion Progression and Variable Permeability to Gadolinium. Arterioscler Thromb Vasc Biol 2023; 43:958-970. [PMID: 37078284 PMCID: PMC10257814 DOI: 10.1161/atvbaha.122.318938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/04/2023] [Indexed: 04/21/2023]
Abstract
BACKGROUND Cerebral cavernous malformations, also known as cavernous angiomas, are blood vessel abnormalities comprised of clusters of grossly enlarged and hemorrhage-prone capillaries. The prevalence in the general population, including asymptomatic cases, is estimated to be 0.5%. Some patients develop severe symptoms, including seizures and focal neurological deficits, whereas others remain asymptomatic. The causes of this remarkable presentation heterogeneity within a primarily monogenic disease remain poorly understood. METHODS We established a chronic mouse model of cerebral cavernous malformations, induced by postnatal ablation of Krit1 with Pdgfb-CreERT2, and examined lesion progression in these mice with T2-weighted 7T magnetic resonance imaging (MRI). We also established a modified protocol for dynamic contrast-enhanced MRI and produced quantitative maps of gadolinium tracer gadobenate dimeglumine. After terminal imaging, brain slices were stained with antibodies against microglia, astrocytes, and endothelial cells. RESULTS These mice develop cerebral cavernous malformations lesions gradually over 4 to 5 months of age throughout the brain. Precise volumetric analysis of individual lesions revealed nonmonotonous behavior, with some lesions temporarily growing smaller. However, the cumulative lesional volume invariably increased over time and after about 2 months followed a power trend. Using dynamic contrast-enhanced MRI, we produced quantitative maps of gadolinium in the lesions, indicating a high degree of heterogeneity in lesional permeability. MRI properties of the lesions were correlated with cellular markers for endothelial cells, astrocytes, and microglia. Multivariate comparisons of MRI properties of the lesions with cellular markers for endothelial and glial cells revealed that increased cell density surrounding lesions correlates with stability, whereas denser vasculature within and surrounding the lesions may correlate with high permeability. CONCLUSIONS Our results lay a foundation for better understanding individual lesion properties and provide a comprehensive preclinical platform for testing new drug and gene therapies for controlling cerebral cavernous malformations.
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Affiliation(s)
- Delaney G. Fisher
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Khadijeh A. Sharifi
- Department of Neuroscience, University of Virginia, Charlottesville, VA
- Department of Neurosurgery, University of Virginia Health System, Charlottesville, VA
| | - E. Zeynep Ulutas
- Department of Neuroscience, Georgia Institute of Technology, Atlanta, GA
| | - Jeyan S. Kumar
- Department of Neurosurgery, University of Virginia Health System, Charlottesville, VA
| | | | - G. Wilson Miller
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
- Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, VA
| | - Richard J. Price
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Petr Tvrdik
- Department of Neuroscience, University of Virginia, Charlottesville, VA
- Department of Neurosurgery, University of Virginia Health System, Charlottesville, VA
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Norat P, Sokolowski JD, Gorick CM, Soldozy S, Kumar JS, Chae Y, Yagmurlu K, Nilak J, Sharifi KA, Walker M, Levitt MR, Klibanov AL, Yan Z, Price RJ, Tvrdik P, Kalani MYS. Intraarterial Transplantation of Mitochondria After Ischemic Stroke Reduces Cerebral Infarction. Stroke Vasc Interv Neurol 2023; 3:e000644. [PMID: 37545759 PMCID: PMC10399028 DOI: 10.1161/svin.122.000644] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 01/03/2023] [Indexed: 08/08/2023]
Abstract
Background- Transplantation of autologous mitochondria into ischemic tissue may mitigate injury caused by ischemia and reperfusion. Methods- Using murine stroke models of middle cerebral artery occlusion, we sought to evaluate feasibility of delivery of viable mitochondria to ischemic brain parenchyma. We evaluated the effects of concurrent focused ultrasound activation of microbubbles, which serves to open the blood-brain barrier, on efficacy of delivery of mitochondria. Results- Following intra-arterial delivery, mitochondria distribute through the stroked hemisphere and integrate into neural and glial cells in the brain parenchyma. Consistent with functional integration in the ischemic tissue, the transplanted mitochondria elevate concentration of adenosine triphosphate in the stroked hemisphere, reduce infarct volume and increase cell viability. Additional of focused ultrasound leads to improved blood brain barrier opening without hemorrhagic complications. Conclusions- Our results have implications for the development of interventional strategies after ischemic stroke and suggest a novel potential modality of therapy after mechanical thrombectomy.
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Affiliation(s)
- Pedro Norat
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Jennifer D. Sokolowski
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Catherine M. Gorick
- Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Sauson Soldozy
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Jeyan S. Kumar
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Youngrok Chae
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Kaan Yagmurlu
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Joelle Nilak
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Khadijeh A. Sharifi
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Melanie Walker
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington
| | - Michael R. Levitt
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington
| | - Alexander L. Klibanov
- Cardiovascular Division, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Zhen Yan
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Richard J. Price
- Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia
| | - M. Yashar S. Kalani
- St. John’s Neuroscience Institute and the University of Oklahoma School of Medicine, Tulsa, Oklahoma
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Yağmurlu K, Sokolowski J, Soldozy S, Norat P, Çırak M, Tvrdik P, Shaffrey ME, Kalani MYS. A subset of arachnoid granulations in humans drain to the venous circulation via intradural lymphatic vascular channels. J Neurosurg 2021; 136:917-926. [PMID: 34416722 DOI: 10.3171/2021.2.jns204455] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/11/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The discovery of dural lymphatics has spurred interest in the mechanisms of drainage of interstitial fluid from the CNS, the anatomical components involved in clearance of macromolecules from the brain, mechanisms of entry and exit of immune components, and how these pathways may be involved in neurodegenerative diseases and cancer metastasis. In this study the authors describe connections between a subset of arachnoid granulations (AGs) and the venous circulation via intradural vascular channels (IVCs), which stain positively with established lymphatic markers. The authors postulate that the AGs may serve as a component of the human brain's lymphatic system. METHODS AGs and IVCs were examined by high-resolution dissection under stereoscope bilaterally in 8 fresh and formalin-fixed human cadaveric heads. The superior sagittal sinus (SSS) and adjacent dura mater were immunostained with antibodies against Lyve-1 (lymphatic marker), podoplanin (lymphatic marker), CD45 (panhematopoietic marker), and DAPI (nuclear marker). RESULTS AGs can be classified as intradural or interdural, depending on their location and site of drainage. Interdural AGs are distinct from the dura, adhere to arachnoid membranes, and occasionally open directly in the inferolateral wall or floor of the SSS, although some cross the infradural folds of the dura's inner layer to meet with intradural AGs and IVCs. Intradural AGs are located within the leaflets of the dura. The total number of openings from the AGs, lateral lacunae, and cortical veins into the SSS was 45 ± 5.62 per head. On average each cadaveric head contained 6 ± 1.30 intradural AGs. Some intradural AGs do not directly open into the SSS and use IVCs to connect to the venous circulation. Using immunostaining methods, the authors demonstrate that these tubular channels stain positively with vascular and lymphatic markers (Lyve-1, podoplanin). CONCLUSIONS AGs consist of two subtypes with differing modes of drainage into the SSS. A subset of AGs located intradurally use tubular channels, which stain positively with vascular and lymphatic markers to connect to the venous lacunae and ultimately to the SSS. The present study suggests that AGs may function as a component of brain lymphatics. This finding has important clinical implications for cancer metastasis to and from the CNS and may shed light on mechanisms of altered clearance of macromolecules in the setting of neurodegenerative diseases.
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Affiliation(s)
- Kaan Yağmurlu
- Departments of1Neurological Surgery and.,2Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia; and
| | - Jennifer Sokolowski
- Departments of1Neurological Surgery and.,2Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia; and
| | - Sauson Soldozy
- Departments of1Neurological Surgery and.,2Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia; and
| | - Pedro Norat
- Departments of1Neurological Surgery and.,2Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia; and
| | | | - Petr Tvrdik
- Departments of1Neurological Surgery and.,2Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia; and
| | | | - M Yashar S Kalani
- 3Department of Surgery, University of Oklahoma School of Medicine, St. John's Neuroscience Institute, Tulsa, Oklahoma
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Coulibaly AP, Pezuk P, Varghese P, Gartman W, Triebwasser D, Kulas JA, Liu L, Syed M, Tvrdik P, Ferris H, Provencio JJ. Neutrophil Enzyme Myeloperoxidase Modulates Neuronal Response in a Model of Subarachnoid Hemorrhage by Venous Injury. Stroke 2021; 52:3374-3384. [PMID: 34404234 PMCID: PMC8478903 DOI: 10.1161/strokeaha.120.033513] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
| | | | | | | | | | | | | | - Mariam Syed
- Department of Neurology (M.S., J.J.P.), University of Virginia, Charlottesville
| | - Petr Tvrdik
- Department of Neuroscience (P.T., H.F., J.J.P.), University of Virginia, Charlottesville.,Department of Neurosurgery (P.T.), University of Virginia, Charlottesville
| | - Heather Ferris
- Department of Neuroscience (P.T., H.F., J.J.P.), University of Virginia, Charlottesville.,Division of Endocrinology, Department of Internal Medicine (H.F.), University of Virginia, Charlottesville
| | - J Javier Provencio
- Department of Neurology (M.S., J.J.P.), University of Virginia, Charlottesville.,Department of Neuroscience (P.T., H.F., J.J.P.), University of Virginia, Charlottesville
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Chen YL, Baker TM, Lee F, Shui B, Lee JC, Tvrdik P, Kotlikoff MI, Sonkusare SK. Calcium Signal Profiles in Vascular Endothelium from Cdh5-GCaMP8 and Cx40-GCaMP2 Mice. J Vasc Res 2021; 58:159-171. [PMID: 33706307 PMCID: PMC8102377 DOI: 10.1159/000514210] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/23/2020] [Indexed: 01/04/2023] Open
Abstract
INTRODUCTION Studies in Cx40-GCaMP2 mice, which express calcium biosensor GCaMP2 in the endothelium under connexin 40 promoter, have identified the unique properties of endothelial calcium signals. However, Cx40-GCaMP2 mouse is associated with a narrow dynamic range and lack of signal in the venous endothelium. Recent studies have proposed many GCaMPs (GCaMP5/6/7/8) with improved properties although their performance in endothelium-specific calcium studies is not known. METHODS We characterized a newly developed mouse line that constitutively expresses GCaMP8 in the endothelium under the VE-cadherin (Cdh5-GCaMP8) promoter. Calcium signals through endothelial IP3 receptors and TRP vanilloid 4 (TRPV4) ion channels were recorded in mesenteric arteries (MAs) and veins from Cdh5-GCaMP8 and Cx40-GCaMP2 mice. RESULTS Cdh5-GCaMP8 mice showed lower baseline fluorescence intensity, higher dynamic range, and higher amplitudes of individual calcium signals than Cx40-GCaMP2 mice. Importantly, Cdh5-GCaMP8 mice enabled the first recordings of discrete calcium signals in the intact venous endothelium and revealed striking differences in IP3 receptor and TRPV4 channel calcium signals between MAs and mesenteric veins. CONCLUSION Our findings suggest that Cdh5-GCaMP8 mice represent significant improvements in dynamic range, sensitivity for low-intensity signals, and the ability to record calcium signals in venous endothelium.
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Affiliation(s)
- Yen Lin Chen
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, USA
| | - Thomas M Baker
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, USA
| | - Frank Lee
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Bo Shui
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Jane C Lee
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Petr Tvrdik
- Departments of Neurosurgery and Neuroscience and Bioengineering, University of Virginia, Charlottesville, Virginia, USA
| | - Michael I Kotlikoff
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Swapnil K Sonkusare
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, USA,
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA,
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Norat P, Soldozy S, Sokolowski JD, Gorick CM, Kumar JS, Chae Y, Yağmurlu K, Prada F, Walker M, Levitt MR, Price RJ, Tvrdik P, Kalani MYS. Author Correction: Mitochondrial dysfunction in neurological disorders: exploring mitochondrial transplantation. NPJ Regen Med 2021; 6:13. [PMID: 33654099 PMCID: PMC7925516 DOI: 10.1038/s41536-021-00125-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Pedro Norat
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA
| | - Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA
| | - Jennifer D Sokolowski
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA
| | - Catherine M Gorick
- Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jeyan S Kumar
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA
| | - Youngrok Chae
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA
| | - Kaan Yağmurlu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA
| | - Francesco Prada
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA.,Acoustic Neuroimaging and Therapy Laboratory, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Focused Ultrasound Foundation, Charlottesville, Virginia, USA
| | - Melanie Walker
- Department of Neurosurgery, University of Washington School of Medicine, Seattle, WA, USA
| | - Michael R Levitt
- Department of Neurosurgery, University of Washington School of Medicine, Seattle, WA, USA
| | - Richard J Price
- Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA. .,Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA.
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA. .,St. John's Neuroscience Institute, Tulsa, OK, 74119, USA.
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11
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Redmon SN, Yarishkin O, Lakk M, Jo A, Mustafić E, Tvrdik P, Križaj D. TRPV4 channels mediate the mechanoresponse in retinal microglia. Glia 2021; 69:1563-1582. [PMID: 33624376 PMCID: PMC8989051 DOI: 10.1002/glia.23979] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 02/02/2021] [Accepted: 02/02/2021] [Indexed: 12/12/2022]
Abstract
The physiological and neurological correlates of plummeting brain osmolality during edema, traumatic CNS injury, and severe ischemia are compounded by neuroinflammation. Using multiple approaches, we investigated how retinal microglia respond to challenges mediated by increases in strain, osmotic gradients, and agonists of the stretch-activated cation channel TRPV4. Dissociated and intact microglia were TRPV4-immunoreactive and responded to the selective agonist GSK1016790A and substrate stretch with altered motility and elevations in intracellular calcium ([Ca2+ ]i ). Agonist- and hypotonicity-induced swelling was associated with a nonselective outwardly rectifying cation current, increased [Ca2+ ]i , and retraction of higher-order processes. The antagonist HC067047 reduced the extent of hypotonicity-induced microglial swelling and inhibited the suppressive effects of GSK1016790A and hypotonicity on microglial branching. Microglial TRPV4 signaling required intermediary activation of phospholipase A2 (PLA2), cytochrome P450, and epoxyeicosatrienoic acid production (EETs). The expression pattern of vanilloid thermoTrp genes in retinal microglia was markedly different from retinal neurons, astrocytes, and cortical microglia. These results suggest that TRPV4 represents a primary retinal microglial sensor of osmochallenges under physiological and pathological conditions. Its activation, associated with PLA2, modulates calcium signaling and cell architecture. TRPV4 inhibition might be a useful strategy to suppress microglial overactivation in the swollen and edematous CNS.
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Affiliation(s)
- Sarah N Redmon
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Oleg Yarishkin
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Andrew Jo
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Edin Mustafić
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, USA.,Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA.,Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, USA
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12
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Yağmurlu K, Sokolowski JD, Çırak M, Urgun K, Soldozy S, Mut M, Shaffrey ME, Tvrdik P, Kalani MYS. Anatomical Features of the Deep Cervical Lymphatic System and Intrajugular Lymphatic Vessels in Humans. Brain Sci 2020; 10:E953. [PMID: 33316930 PMCID: PMC7763972 DOI: 10.3390/brainsci10120953] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/05/2020] [Accepted: 12/07/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Studies in rodents have re-kindled interest in the study of lymphatics in the central nervous system. Animal studies have demonstrated that there is a connection between the subarachnoid space and deep cervical lymph nodes (DCLNs) through dural lymphatic vessels located in the skull base and the parasagittal area. OBJECTIVE To describe the connection of the DCLNs and lymphatic tributaries with the intracranial space through the jugular foramen, and to address the anatomical features and variations of the DCLNs and associated lymphatic channels in the neck. METHODS Twelve formalin-fixed human head and neck specimens were studied. Samples from the dura of the wall of the jugular foramen were obtained from two fresh human cadavers during rapid autopsy. The samples were immunostained with podoplanin and CD45 to highlight lymphatic channels and immune cells, respectively. RESULTS The mean number of nodes for DCLNs was 6.91 ± 0.58 on both sides. The mean node length was 10.1 ± 5.13 mm, the mean width was 7.03 ± 1.9 mm, and the mean thickness was 4 ± 1.04 mm. Immunohistochemical staining from rapid autopsy samples demonstrated that lymphatic vessels pass from the intracranial compartment into the neck through the meninges at the jugular foramen, through tributaries that can be called intrajugular lymphatic vessels. CONCLUSIONS The anatomical features of the DCLNs and their connections with intracranial lymphatic structures through the jugular foramen represent an important possible route for the spread of cancers to and from the central nervous system; therefore, it is essential to have an in-depth understanding of the anatomy of these lymphatic structures and their variations.
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Affiliation(s)
- Kaan Yağmurlu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA 22903, USA
| | - Jennifer D. Sokolowski
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA 22903, USA
| | - Musa Çırak
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
| | - Kamran Urgun
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
| | - Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA 22903, USA
| | - Melike Mut
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
- Department of Neurosurgery, Hacettepe University, P.O. Box 06230 Ankara, Turkey
| | - Mark E. Shaffrey
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA 22903, USA
| | - M. Yashar S. Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA 22903, USA; (K.Y.); (J.D.S.); (M.Ç.); (K.U.); (S.S.); (M.M.); (M.E.S.); (P.T.)
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA 22903, USA
- Department of Neurosurgery, St. John’s Neuroscience Institute, School of Medicine, University of Oklahoma, Tulsa, OK 74104, USA
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13
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Liu L, Kearns KN, Eli I, Sharifi KA, Soldozy S, Carlson EW, Scott KW, Sluzewski MF, Acton ST, Stauderman KA, Kalani MYS, Park M, Tvrdik P. Microglial Calcium Waves During the Hyperacute Phase of Ischemic Stroke. Stroke 2020; 52:274-283. [PMID: 33161850 DOI: 10.1161/strokeaha.120.032766] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE Ischemic injury triggers multiple pathological responses in the brain tissue, including spreading depolarizations across the cerebral cortex (cortical spreading depolarizations [CSD]). Microglia have been recently shown to play a significant role in the propagation of CSD. However, the intracellular responses of myeloid cells during ischemic stroke have not been investigated. METHODS We have studied intracellular calcium activity in cortical microglia in the stroke model of the middle cerebral artery occlusion, using the murine Polr2a-based and Cre-dependent GCaMP5 and tdTomato reporter (PC::G5-tdT). High-speed 2-photon microscopy through cranial windows was employed to record signals from genetically encoded indicators of calcium. Inflammatory stimuli and pharmacological inhibition were used to modulate microglial calcium responses in the somatosensory cortex. RESULTS In vivo imaging revealed periodical calcium activity in microglia during the hyperacute phase of ischemic stroke. This activity was more frequent during the first 6 hours after occlusion, but the amplitudes of calcium transients became larger at later time points. Consistent with CSD nature of these events, we reproducibly triggered comparable calcium transients with microinjections of potassium chloride (KCl) into adjacent cortical areas. Furthermore, lipopolysaccharide-induced peripheral inflammation, mimicking sterile inflammation during ischemic stroke, produced significantly greater microglial calcium transients during CSD. Finally, in vivo pharmacological analysis with CRAC (calcium release-activated channel) inhibitor CM-EX-137 demonstrated that CSD-associated microglial calcium transients after KCl microinjections are mediated at least in part by the CRAC mechanism. CONCLUSIONS Our findings demonstrate that microglia participate in ischemic brain injury via previously undetected mechanisms, which may provide new avenues for therapeutic interventions.
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Affiliation(s)
- Lei Liu
- Department of Neurological Surgery (L.L., K.N.K., K.A. Sharifi, S.S., K.W.S., M.Y.S.K., M.P., P.T.), University of Virginia Health System, Charlottesville
| | - Kathryn N Kearns
- Department of Neurological Surgery (L.L., K.N.K., K.A. Sharifi, S.S., K.W.S., M.Y.S.K., M.P., P.T.), University of Virginia Health System, Charlottesville
| | - Ilyas Eli
- Department of Neurosurgery (I.E., E.W.C.), University of Utah School of Medicine, Salt Lake City
| | - Khadijeh A Sharifi
- Department of Neurological Surgery (L.L., K.N.K., K.A. Sharifi, S.S., K.W.S., M.Y.S.K., M.P., P.T.), University of Virginia Health System, Charlottesville
- Department of Neuroscience (K.A. Sharifi, M.Y.S.K., P.T.), University of Virginia Health System, Charlottesville
| | - Sauson Soldozy
- Department of Neurological Surgery (L.L., K.N.K., K.A. Sharifi, S.S., K.W.S., M.Y.S.K., M.P., P.T.), University of Virginia Health System, Charlottesville
| | - Elizabeth W Carlson
- Department of Neurosurgery (I.E., E.W.C.), University of Utah School of Medicine, Salt Lake City
| | - Kyle W Scott
- Department of Neurological Surgery (L.L., K.N.K., K.A. Sharifi, S.S., K.W.S., M.Y.S.K., M.P., P.T.), University of Virginia Health System, Charlottesville
| | - M Filip Sluzewski
- Department of Electrical and Computer Engineering (M.F.S., S.T.A.), University of Virginia Health System, Charlottesville
| | - Scott T Acton
- Department of Electrical and Computer Engineering (M.F.S., S.T.A.), University of Virginia Health System, Charlottesville
| | | | - M Yashar S Kalani
- Department of Neurological Surgery (L.L., K.N.K., K.A. Sharifi, S.S., K.W.S., M.Y.S.K., M.P., P.T.), University of Virginia Health System, Charlottesville
- Department of Neuroscience (K.A. Sharifi, M.Y.S.K., P.T.), University of Virginia Health System, Charlottesville
| | - Min Park
- Department of Neurological Surgery (L.L., K.N.K., K.A. Sharifi, S.S., K.W.S., M.Y.S.K., M.P., P.T.), University of Virginia Health System, Charlottesville
| | - Petr Tvrdik
- Department of Neurological Surgery (L.L., K.N.K., K.A. Sharifi, S.S., K.W.S., M.Y.S.K., M.P., P.T.), University of Virginia Health System, Charlottesville
- Department of Neuroscience (K.A. Sharifi, M.Y.S.K., P.T.), University of Virginia Health System, Charlottesville
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14
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Soldozy S, Galindo J, Snyder H, Ali Y, Norat P, Yağmurlu K, Sokolowski JD, Sharifi K, Tvrdik P, Park MS, Kalani MYS. Clinical utility of arterial spin labeling imaging in disorders of the nervous system. Neurosurg Focus 2020; 47:E5. [PMID: 31786550 DOI: 10.3171/2019.9.focus19567] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 09/16/2019] [Indexed: 11/06/2022]
Abstract
Neuroimaging is an indispensable tool in the workup and management of patients with neurological disorders. Arterial spin labeling (ASL) is an imaging modality that permits the examination of blood flow and perfusion without the need for contrast injection. Noninvasive in nature, ASL provides a feasible alternative to existing vascular imaging techniques, including angiography and perfusion imaging. While promising, ASL has yet to be fully incorporated into the diagnosis and management of neurological disorders. This article presents a review of the most recent literature on ASL, with a special focus on its use in moyamoya disease, brain neoplasms, seizures, and migraines and a commentary on recent advances in ASL that make the imaging technique more attractive as a clinically useful tool.
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15
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Soldozy S, Akyeampong DK, Barquin DL, Norat P, Yağmurlu K, Sokolowski JD, Sharifi KA, Tvrdik P, Park MS, Kalani MYS. Systematic Review of Functional Mapping and Cortical Reorganization in the Setting of Arteriovenous Malformations, Redefining Anatomical Eloquence. Front Surg 2020; 7:514247. [PMID: 33195382 PMCID: PMC7555608 DOI: 10.3389/fsurg.2020.514247] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 08/18/2020] [Indexed: 11/13/2022] Open
Abstract
Objective: The goal of this study was to systematically review functional mapping and reorganization that takes place in the setting of arteriovenous malformations (AVMs) and its potential impact on grading and surgical decision making. Methods: A systematic literature review was performed using the PubMed database for studies published between 1986 and 2019. Studies assessing brain mapping and functional reorganization in AVMs were included. Results: Of the total 84 articles identified in the original literature search, 12 studies were ultimately selected. This includes studies evaluating the impact of cortical reorganization on patient outcomes and factors impacting and triggering cortical reorganization in AVM. Conclusion: These studies demonstrate the utility of preoperative brain mapping and acknowledgment of functional reorganization in the setting of AVMs. While these findings led to alterations in Spetzler–Martin grading and subsequent surgical decision making, it remains unclear the clinical utility of this information when assessing patient outcomes. While promising, more research is required before recommendations can be made regarding functional brain mapping and cortical reorganization with respect to AVM surgery involving eloquent brain tissue.
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Affiliation(s)
- Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Daniel K Akyeampong
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - David L Barquin
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Pedro Norat
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Kaan Yağmurlu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Jennifer D Sokolowski
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Khadijeh A Sharifi
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Min S Park
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
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16
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Soldozy S, Norat P, Elsarrag M, Chatrath A, Costello JS, Sokolowski JD, Tvrdik P, Kalani MYS, Park MS. The biophysical role of hemodynamics in the pathogenesis of cerebral aneurysm formation and rupture. Neurosurg Focus 2020; 47:E11. [PMID: 31261115 DOI: 10.3171/2019.4.focus19232] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 04/18/2019] [Indexed: 11/06/2022]
Abstract
The pathogenesis of intracranial aneurysms remains complex and multifactorial. While vascular, genetic, and epidemiological factors play a role, nascent aneurysm formation is believed to be induced by hemodynamic forces. Hemodynamic stresses and vascular insults lead to additional aneurysm and vessel remodeling. Advanced imaging techniques allow us to better define the roles of aneurysm and vessel morphology and hemodynamic parameters, such as wall shear stress, oscillatory shear index, and patterns of flow on aneurysm formation, growth, and rupture. While a complete understanding of the interplay between these hemodynamic variables remains elusive, the authors review the efforts that have been made over the past several decades in an attempt to elucidate the physical and biological interactions that govern aneurysm pathophysiology. Furthermore, the current clinical utility of hemodynamics in predicting aneurysm rupture is discussed.
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17
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Soldozy S, Skaff A, Soldozy K, Sokolowski JD, Norat P, Yagmurlu K, Sharifi KA, Tvrdik P, Park MS, Kalani MYS, Jane JA, Syed HR. From Bench to Bedside, the Current State of Oncolytic Virotherapy in Pediatric Glioma. Neurosurgery 2020; 87:1091-1097. [PMID: 32542365 DOI: 10.1093/neuros/nyaa247] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 04/10/2020] [Indexed: 12/26/2022] Open
Abstract
Glioma continues to be a challenging disease process, making up the most common tumor type within the pediatric population. While low-grade gliomas are typically amenable to surgical resection, higher grade gliomas often require additional radiotherapy in conjunction with adjuvant chemotherapy. Molecular profiling of these lesions has led to the development of various pharmacologic and immunologic agents, although these modalities are not without great systemic toxicity. In addition, the molecular biology of adult glioma and pediatric glioma has been shown to differ substantially, making the application of current chemotherapies dubious in children and adolescents. For this reason, therapies with high tumor specificity based on pediatric tumor cell biology that spare healthy tissue are needed. Oncolytic virotherapy serves to fill this niche, as evidenced by renewed interest in this domain of cancer therapy. Initially discovered by chance in the early 20th century, virotherapy has emerged as a viable treatment option. With promising results based on preclinical studies, the authors review several oncolytic viruses, with a focus on molecular mechanism and efficacy of these viruses in tumor cell lines and murine models. In addition, current phase I clinical trials evaluating oncolytic virotherapy in the treatment of pediatric glioma are summarized.
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Affiliation(s)
- Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.,Deparment of Neuroscience, University of Virginia Health System, Charlottesville, Virginia
| | - Anthony Skaff
- Deparment of Neuroscience, University of Virginia Health System, Charlottesville, Virginia
| | - Kamron Soldozy
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
| | - Jennifer D Sokolowski
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.,Deparment of Neuroscience, University of Virginia Health System, Charlottesville, Virginia
| | - Pedro Norat
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.,Deparment of Neuroscience, University of Virginia Health System, Charlottesville, Virginia
| | - Kaan Yagmurlu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.,Deparment of Neuroscience, University of Virginia Health System, Charlottesville, Virginia
| | - Khadijeh A Sharifi
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.,Deparment of Neuroscience, University of Virginia Health System, Charlottesville, Virginia
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.,Deparment of Neuroscience, University of Virginia Health System, Charlottesville, Virginia
| | - Min S Park
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia.,Deparment of Neuroscience, University of Virginia Health System, Charlottesville, Virginia
| | - John A Jane
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
| | - Hasan R Syed
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
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18
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Soldozy S, Costello JS, Norat P, Sokolowski JD, Soldozy K, Park MS, Tvrdik P, Kalani MYS. Extracranial-intracranial bypass approach to cerebral revascularization: a historical perspective. Neurosurg Focus 2020; 46:E2. [PMID: 30717070 DOI: 10.3171/2018.11.focus18527] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 11/26/2018] [Indexed: 11/06/2022]
Abstract
While the majority of cerebral revascularization advancements were made in the last century, it is worth noting the humble beginnings of vascular surgery throughout history to appreciate its progression and application to neurovascular pathology in the modern era. Nearly 5000 years of basic human inquiry into the vasculature and its role in neurological disease has resulted in the complex neurosurgical procedures used today to save and improve lives. This paper explores the story of the extracranial-intracranial approach to cerebral revascularization.
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Affiliation(s)
- Sauson Soldozy
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - John S Costello
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - Pedro Norat
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - Jennifer D Sokolowski
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - Kamron Soldozy
- 2Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
| | - Min S Park
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - Petr Tvrdik
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - M Yashar S Kalani
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and
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19
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Elsarrag M, Soldozy S, Patel P, Norat P, Sokolowski JD, Park MS, Tvrdik P, Kalani MYS. Enhanced recovery after spine surgery: a systematic review. Neurosurg Focus 2020; 46:E3. [PMID: 30933920 DOI: 10.3171/2019.1.focus18700] [Citation(s) in RCA: 128] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 01/25/2019] [Indexed: 02/07/2023]
Abstract
OBJECTIVEEnhanced recovery after surgery (ERAS) is a multidimensional approach to improving the care of surgical patients using subspecialty- and procedure-specific evidence-based protocols. The literature provides evidence of the benefits of ERAS implementation, which include expedited functional recovery, decreased postoperative morbidity, reduced costs, and improved subjective patient experience. Although extensively examined in other surgical areas, ERAS principles have been applied to spine surgery only in recent years. The authors examine studies investigating the application of ERAS programs to patients undergoing spine surgery.METHODSThe authors conducted a systematic review of the PubMed and MEDLINE databases up to November 20, 2018.RESULTSTwenty full-text articles were included in the qualitative analysis. The majority of studies were retrospective reviews of nonrandomized data sets or qualitative investigations lacking formal control groups; there was 1 protocol for a future randomized controlled trial. Most studies demonstrated reduced lengths of stay and no increase in rates of readmissions or complications after introduction of an ERAS pathway.CONCLUSIONSThese introductory studies demonstrate the potential of ERAS protocols, when applied to spine procedures, to reduce lengths of stay, accelerate return of function, minimize postoperative pain, and save costs.
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20
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Soldozy S, Norat P, Yağmurlu K, Sokolowski JD, Sharifi KA, Tvrdik P, Park MS, Kalani MYS. Arteriovenous malformation presenting with epilepsy: a multimodal approach to diagnosis and treatment. Neurosurg Focus 2020; 48:E17. [DOI: 10.3171/2020.1.focus19899] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 01/28/2020] [Indexed: 11/06/2022]
Abstract
Arteriovenous malformation (AVM) presenting with epilepsy significantly impacts patient quality of life, and it should be considered very much a seizure disorder. Although hemorrhage prevention is the primary treatment aim of AVM surgery, seizure control should also be at the forefront of therapeutic management. Several hemodynamic and morphological characteristics of AVM have been identified to be associated with seizure presentation. This includes increased AVM flow, presence of long pial draining vein, venous outflow obstruction, and frontotemporal location, among other aspects. With the advent of high-throughput image processing and quantification methods, new radiographic attributes of AVM-related epilepsy have been identified. With respect to therapy, several treatment approaches are available, including conservative management or interventional modalities; this includes microsurgery, radiosurgery, and embolization or a combination thereof. Many studies, especially in the domain of microsurgery and radiosurgery, evaluate both techniques with respect to seizure outcomes. The advantage of microsurgery lies in superior AVM obliteration rates and swift seizure response. In addition, by incorporating electrophysiological monitoring during AVM resection, adjacent or even remote epileptogenic foci can be identified, leading to extended lesionectomy and improved seizure control. Radiosurgery, despite resulting in reduced AVM obliteration and prolonged time to seizure freedom, avoids the risks of surgery altogether and may provide seizure control through various antiepileptic mechanisms. Embolization continues to be used as an adjuvant for both microsurgery and radiosurgery. In this study, the authors review the latest imaging techniques in characterizing AVM-related epilepsy, in addition to reviewing each treatment modality.
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Kearns KN, Chen CJ, Tvrdik P, Park MS, Kalani MYS. Outcomes of basal ganglia and thalamic cavernous malformation surgery: A meta-analysis. J Clin Neurosci 2020; 73:209-214. [PMID: 32057609 DOI: 10.1016/j.jocn.2019.12.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 12/01/2019] [Indexed: 12/01/2022]
Abstract
Surgical resection of basal ganglia (BG) and thalamic cavernous malformations (CMs) has not yet become standardized in the field of neurosurgery due to the eloquent location of these lesions and the relative paucity of literature on the subject. This review presents a consolidation of the available literature on outcomes and complication rates after surgical resection of these lesions. A systematic literature review was performed via PubMed database for articles published between 1985 and 2019. Studies comprising ≥2 patients receiving surgery for BG or thalamic CMs with available follow-up data were included. Pooled data included patient demographics, CM preoperative characteristics, and surgical outcomes Twenty studies comprising 227 patients were included for analysis. Complete resection was achieved in 94.7% (fixed-effects pooled estimate [FE]: 94.9%[91.0%-97.8%]; random-effects pooled estimate [RE]: 90.0%[79.8%-96.9%]), and hemorrhage of incompletely resected CMs occurred in 50% (FE: 55.9%[25.9%-83.6%]; RE: 55.9%[25.9%-83.6%]) of patients. Early morbidity was observed in 24.0% (FE: 24.9%[17.8%-32.6%]; RE: 24.9%[17.8%-32.6%]). At final follow-up, 67.3% (FE: 67.7%[58.8%-76.0%]; RE: 67.8%[52.2%-81.6%]) and 20.6% (FE: 20.6%[13.6%-28.6%]; RE: 20.9%[9.8%-34.9%]) had improvement and stability of preoperative symptoms, respectively. Mortality rate was 1.3% (FE: 2.3%[0.6%-5.1%]; RE: 2.3%[0.6%-5.1%]). Therefore, high cure rates with low rates of postoperative morbidity can be achieved in BG or thalamic CM surgery. Most patients had improved neurological function at final follow-up. Complete resection should be attempted to reduce rates of repeat hemorrhage.
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Affiliation(s)
- Kathryn N Kearns
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Ching-Jen Chen
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Min S Park
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States.
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22
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Costello JS, Soldozy S, Norat P, Sokolowski JD, Yağmurlu K, Sharifi K, Tvrdik P, Park MS, Kalani MYS. Endovascular Approach to Cerebral Revascularization: Historical Vignette. World Neurosurg 2020; 136:258-262. [PMID: 31954910 DOI: 10.1016/j.wneu.2020.01.072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 01/09/2020] [Accepted: 01/09/2020] [Indexed: 10/25/2022]
Abstract
From their origins as cardiovascular research tools, endovascular techniques have evolved to provide a minimally invasive means of diagnosis and therapy for individuals suffering from occlusive artery disease. The techniques were pioneered by William Harvey, whose work set the stage for all subsequent endovascular experiments. These included the bold self-catheterization procedure performed by Werner Forssmann in 1929, which would lead to his dismissal by his superiors, only to regain respect within the medical community in 1956 on receiving the Nobel Prize. Charles Dotter was the first to understand the true potential of endovascular approaches after a chance recanalization that would catapult arterial catheterization first into the cardiovascular surgical arena, then into neurosurgery for intracranial stenoses. Having been meticulously evaluated and compared with open vascular procedures, endovascular neurosurgery has continued to be refined and optimized. Understanding the history and development of these techniques and their applications in neurosurgery is necessary to appreciate the current clinical utility of these procedures, serving to provide the vascular neurosurgeon a greater array of treatment options for patients. Here we explore the major scientific and technological advancements that facilitated the development of the endovascular approach to cerebral revascularization, as well as current indications and ongoing clinical trials.
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Affiliation(s)
- John S Costello
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA.
| | - Pedro Norat
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Jennifer D Sokolowski
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Kaan Yağmurlu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Khadijeh Sharifi
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Min S Park
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
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Soldozy S, Sharifi KA, Desai B, Giraldo D, Yeghyayan M, Liu L, Norat P, Sokolowski JD, Yağmurlu K, Park MS, Tvrdik P, Kalani MYS. Cortical Spreading Depression in the Setting of Traumatic Brain Injury. World Neurosurg 2019; 134:50-57. [PMID: 31655239 DOI: 10.1016/j.wneu.2019.10.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/06/2019] [Accepted: 10/08/2019] [Indexed: 12/31/2022]
Abstract
Cortical spreading depression (CSD) is a pathophysiologic phenomenon that describes an expanding wave of depolarization within the cortical gray matter. Originally described over 70 years ago, this spreading depression disrupts neuronal and glial ionic equilibrium, leading to increased energy demands that can cause a metabolic crisis. This results in secondary insult, further perpetuating brain injury and neuronal death. Initially not thought to be of clinical significance, the view of CSD was modified with the advent of intracranial electroencephalography, or electrocorticography. With these improved monitoring techniques, CSD has been identified as a major mechanism by which traumatic brain injury (TBI) imparts its negative sequalae. TBI is a heterogenous disease process that runs the gamut of clinical presentations. This includes concussion, epidural and subdural hematoma, diffuse axonal injury, and subarachnoid hemorrhage. Nonetheless, CSD appears to be frequently occurring among the various types of TBI, thus allowing for the potential development of targeted therapies in an otherwise ill-fated patient cohort. Although a complete understanding of the interplay between CSD and TBI has not yet been achieved, the authors recount the efforts that have been employed over the last several decades in an effort to bridge this gap. In addition, our current understanding of the role neuroimmune cells play in CSD is discussed in the context of TBI. Finally, current therapeutic strategies using CSD as a pharmacologic target are explored with respect to their clinical use in patients with TBI.
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Affiliation(s)
- Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Khadijeh A Sharifi
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA; Department of Neuroscience, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Bhargav Desai
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Daniel Giraldo
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Michelle Yeghyayan
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Lei Liu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA; Department of Neuroscience, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Pedro Norat
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Jennifer D Sokolowski
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Kaan Yağmurlu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Min S Park
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA; Department of Neuroscience, University of Virginia Health System, Charlottesville, Virginia, USA
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA; Department of Neuroscience, University of Virginia Health System, Charlottesville, Virginia, USA.
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Abstract
Background and Purpose—
The goal of this study was to systematically review the outcomes and complications after surgical resection of brain stem cavernous malformations (BCMs).
Methods—
A systematic literature review was performed using the PubMed database for studies published between 1986 and 2018. All studies comprising ≥2 patients with surgically resected BCMs and available follow-up data were included. Data extracted from studies included patient demographics, BCM location, and surgical outcomes.
Results—
Eighty-six studies comprising 2493 patients (adult and pediatric) were included for final analysis. Complete resection was achieved in 92.3% (fixed-effects pooled estimate [FE], 92.9% [91.7%–94.0%]; random-effects pooled estimate [RE], 89.4% [86.5%–92.0%]) of patients, and rehemorrhage of residual BCMs occurred in 58.6% (FE, 58.8% [49.7%–67.6%]; RE, 57.2% [43.5%–70.2%]). Postoperative morbidity occurred in 34.8% (FE, 30.9% [29.0%–32.8%]; RE, 31.1% [25.8%–36.6%]) of patients. Postoperative morbidities included motor deficit in 11.0% (FE, 9.9% [8.1%–11.7%]; RE, 11.1% [7.0%–16.0%]), sensory deficit in 6.7% (FE, 6.3% [4.8%–7.9%]; RE, 7.6% [4.5%–11.5%]), tracheostomy/gastrostomy in 6.0% (FE, 5.2% [4.3%–6.1%]; RE, 3.8% [2.6%–5.3%]), and other cranial nerve deficits in 29.4% (FE, 27.6% [25.3%–29.9%]; RE, 33.9% [25.7%–42.6%]) of patients. At final follow-up, 57.9% (FE, 57.6% [55.6%–59.6%]; RE, 57.2% [52.1%–62.3%]) and 25.9% (FE, 24.1% [22.4%–25.9%]; RE, 18.5% [14.6%–22.8%]) of patients had improvement and stability of preoperative symptoms, respectively. Mortality rate was 1.6% (FE, 1.9% [1.4%–2.5%]; RE, 1.8% [1.4%–2.5%]).
Conclusions—
High cure rates and low rates of postoperative morbidity can be achieved with surgery in patients with BCMs. Most patients had improved preoperative symptoms at final follow-up. To avoid rehemorrhage, complete resection should be the goal of surgery.
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Affiliation(s)
- Kathryn N. Kearns
- From the Department of Neurological Surgery, University of Virginia Health System, Charlottesville
| | - Ching-Jen Chen
- From the Department of Neurological Surgery, University of Virginia Health System, Charlottesville
| | - Petr Tvrdik
- From the Department of Neurological Surgery, University of Virginia Health System, Charlottesville
| | - Min S. Park
- From the Department of Neurological Surgery, University of Virginia Health System, Charlottesville
| | - M. Yashar S. Kalani
- From the Department of Neurological Surgery, University of Virginia Health System, Charlottesville
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Norat P, Soldozy S, Elsarrag M, Sokolowski J, Yaǧmurlu K, Park MS, Tvrdik P, Kalani MYS. Application of Indocyanine Green Videoangiography in Aneurysm Surgery: Evidence, Techniques, Practical Tips. Front Surg 2019; 6:34. [PMID: 31281818 PMCID: PMC6596320 DOI: 10.3389/fsurg.2019.00034] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 05/22/2019] [Indexed: 12/29/2022] Open
Abstract
Establishing blood vessel patency in neurovascular surgery is an essential component in treating cerebrovascular disorders. Given the difficulty in confirming complete obliteration of the aneurysm sac, ICG videoangiography has emerged as an intraoperative tool that provides neurosurgeons immediate feedback on the status of vessel flow, allowing for surgical modifications to be made without delay. ICG initially emerged as a tool for assessing hepatic, cardiac, and retinovascular function. It is an inert compound with a high affinity for plasma proteins and fluorescence properties making it the ideal candidate for assessment of vessel patency in neurovascular procedures. Requiring only a bolus peripheral vein injection and integration of a near-infrared imaging device into the surgical microscope, ICG can be visualized without disrupting operating room workflow or the surgical field. Quick response time, high-spatial resolution, and low complication rates are features of ICG videoangiography that prove advantageous when compared to the gold standard intra- and postoperative digital subtraction angiography (DSA). Despite this, ICG is not without limitations, specifically in the setting of atherosclerotic vessels, giant, and complex aneurysms. Additionally, there are instances where DSA may prove superior in detecting vessel stenosis and outflow obstruction, prompting the recommendation of ICG as an adjunct to, rather than complete replacement of DSA. In this article, the authors provide a brief overview of the biochemical properties and historical origins of ICG viedoangiography in addition to discussing its current application in aneurysm surgery.
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Affiliation(s)
- Pedro Norat
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Mazin Elsarrag
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Jennifer Sokolowski
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Kaan Yaǧmurlu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Min S Park
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
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Abstract
Calcium signaling plays a significant role in microglial activation. Genetically encoded calcium indicators (GECI) have been widely used for calcium imaging studies in many brain cell types, including neurons, astrocytes, and oligodendrocytes. However, microglial calcium imaging approaches have been hampered by idiosyncrasies of their gene expression and malleable cell properties. The generation of PC::G5-tdT, a Polr2a locus-based conditional mouse reporter of calcium, facilitated the deployment of GECI in microglia. When crossed with the Iba1(Aif1)-IRES-Cre line, all brain microglia of the progeny are labeled with the calcium indicator variant GCaMP5G and the red fluorescent protein tdTomato. This reporter system has enabled in vivo studies of intracellular calcium in large microglial cell populations in cerebral pathologies such as ischemic stroke. In this chapter, we outline specific guidelines for genetic, surgical, imaging, and data analysis aspects of microglial calcium monitoring of the ischemic cortex following middle cerebral artery occlusion.
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Affiliation(s)
- Petr Tvrdik
- Department of Neurosurgery, School of Medicine, University of Virginia, Charlottesville, VA, USA.
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, USA.
| | - Kathryn N Kearns
- Department of Neurosurgery, School of Medicine, University of Virginia, Charlottesville, VA, USA
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Khadijeh A Sharifi
- Department of Neurosurgery, School of Medicine, University of Virginia, Charlottesville, VA, USA
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - M Filip Sluzewski
- Department of Electrical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Scott T Acton
- Department of Electrical Engineering, University of Virginia, Charlottesville, VA, USA
| | - M Yashar S Kalani
- Department of Neurosurgery, School of Medicine, University of Virginia, Charlottesville, VA, USA
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, USA
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Chen CJ, Norat P, Ding D, Mendes GAC, Tvrdik P, Park MS, Kalani MY. Transvenous embolization of brain arteriovenous malformations: a review of techniques, indications, and outcomes. Neurosurg Focus 2018; 45:E13. [DOI: 10.3171/2018.3.focus18113] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Endovascular embolization of brain arteriovenous malformations (AVMs) is conventionally performed from a transarterial approach. Transarterial AVM embolization can be a standalone treatment or, more commonly, used as a neoadjuvant therapy prior to microsurgery or stereotactic radiosurgery. In contrast to the transarterial approach, curative embolization of AVMs may be more readily achieved from a transvenous approach. Transvenous embolization is considered a salvage therapy in contemporary AVM management. Proposed indications for this approach include a small (diameter < 3 cm) and compact AVM nidus, deep AVM location, hemorrhagic presentation, single draining vein, lack of an accessible arterial pedicle, exclusive arterial supply by perforators, and en passage feeding arteries. Available studies of transvenous AVM embolization in the literature have reported high complete obliteration rates, with reasonably low complication rates. However, evaluating the efficacy and safety of this approach is challenging due to the limited number of published cases. In this review the authors describe the technical considerations, indications, and outcomes of transvenous AVM embolization.
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Affiliation(s)
- Ching-Jen Chen
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
| | - Pedro Norat
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
| | - Dale Ding
- 2Department of Neurosurgery, Barrow Neurological Institute, Phoenix, Arizona; and
| | - George A. C. Mendes
- 3Department of Interventional Neuroradiology, Hôpital Dupuytren, Centre Regional Hospitalier Universitaire de Limoges, France
| | - Petr Tvrdik
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
| | - Min S. Park
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
| | - M. Yashar Kalani
- 1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
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Puelles L, Tvrdik P, Martínez-de-la-torre M. The Postmigratory Alar Topography of Visceral Cranial Nerve Efferents Challenges the Classical Model of Hindbrain Columns. Anat Rec (Hoboken) 2018; 302:485-504. [DOI: 10.1002/ar.23830] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Luis Puelles
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, School of Medicine; University of Murcia; Murcia 30071 Spain
| | - Petr Tvrdik
- Department of Neurosurgery-Physiology; University of Utah; Salt Lake City, Utah 84112
| | - Margaret Martínez-de-la-torre
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, School of Medicine; University of Murcia; Murcia 30071 Spain
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Watson C, Tvrdik P. Spinal Accessory Motor Neurons in the Mouse: A Special Type of Branchial Motor Neuron? Anat Rec (Hoboken) 2018; 302:505-511. [DOI: 10.1002/ar.23822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 10/10/2017] [Accepted: 10/10/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Charles Watson
- School of Animal Biology; University of Western Australia; Perth Australia
- Neuroscience Research Australia; Sydney Australia
| | - Petr Tvrdik
- Department of Neurosurgery; University of Utah; Salt Lake City Utah
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Tvrdik P, Kalani MYS. In Vivo Imaging of Microglial Calcium Signaling in Brain Inflammation and Injury. Int J Mol Sci 2017; 18:ijms18112366. [PMID: 29117112 PMCID: PMC5713335 DOI: 10.3390/ijms18112366] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 11/01/2017] [Accepted: 11/04/2017] [Indexed: 12/20/2022] Open
Abstract
Microglia, the innate immune sentinels of the central nervous system, are the most dynamic cells in the brain parenchyma. They are the first responders to insult and mediate neuroinflammation. Following cellular damage, microglia extend their processes towards the lesion, modify their morphology, release cytokines and other mediators, and eventually migrate towards the damaged area and remove cellular debris by phagocytosis. Intracellular Ca2+ signaling plays important roles in many of these functions. However, Ca2+ in microglia has not been systematically studied in vivo. Here we review recent findings using genetically encoded Ca2+ indicators and two-photon imaging, which have enabled new insights into Ca2+ dynamics and signaling pathways in large populations of microglia in vivo. These new approaches will help to evaluate pre-clinical interventions and immunomodulation for pathological brain conditions such as stroke and neurodegenerative diseases.
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Affiliation(s)
- Petr Tvrdik
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
| | - M Yashar S Kalani
- Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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31
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Watson C, Leanage G, Makki N, Tvrdik P. Escapees from Rhombomeric Lineage Restriction: Extensive Migration Rostral to the r4/r5 Border of Hox-a3 Expression. Anat Rec (Hoboken) 2017; 300:1838-1846. [PMID: 28667681 DOI: 10.1002/ar.23628] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/15/2016] [Accepted: 10/19/2016] [Indexed: 12/20/2022]
Abstract
The rhombomeric compartments of the hindbrain are characterized by lineage restriction; cells born in one compartment generally remain there and do not migrate to neighboring rhombomeres. Two well-known exceptions are the substantial migrations of the pontine nuclei and the mammalian facial nucleus. In this study we used Hoxa3-Cre lineage to permanently mark cells that originate in rhombomeres caudal to r4. We found that cells born caudal to the r4/r5 border migrate forwards to a number of different locations in rhombomeres 1-4; the final locations include the interfascicular trigeminal nucleus, the principal trigeminal nucleus, the pontine nuclei, the reticulotegmental nucleus, the ventral nucleus of the lateral lemniscus, and the lateral and medial vestibular nuclei. We suggest that there are numerous exceptions to the principle of rhombomeric lineage restriction that have previously gone unnoticed. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1838-1846, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Charles Watson
- Faculty of Health Sciences, Curtin University, Perth, Australia.,Neurosciences Research Australia, Sydney, Australia
| | - Gayeshika Leanage
- Faculty of Medicine, University of Western Australia, Perth, Australia
| | - Nadja Makki
- Department of Bioengineering and Therapeutic Science, University of California San Francisco, San Francisco, California
| | - Petr Tvrdik
- Department of Neurosurgery, University of Utah, Salt Lake City, Utah
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32
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Ruff JS, Saffarini RB, Ramoz LL, Morrison LC, Baker S, Laverty SM, Tvrdik P, Capecchi MR, Potts WK. Mouse fitness measures reveal incomplete functional redundancy of Hox paralogous group 1 proteins. PLoS One 2017; 12:e0174975. [PMID: 28380068 PMCID: PMC5381901 DOI: 10.1371/journal.pone.0174975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/17/2017] [Indexed: 11/26/2022] Open
Abstract
Here we assess the fitness consequences of the replacement of the Hoxa1 coding region with its paralog Hoxb1 in mice (Mus musculus) residing in semi-natural enclosures. Previously, this Hoxa1B1 swap was reported as resulting in no discernible embryonic or physiological phenotype (i.e., functionally redundant), despite the 51% amino acid sequence differences between these two Hox proteins. Within heterozygous breeding cages no differences in litter size nor deviations from Mendelian genotypic expectations were observed in the outbred progeny; however, within semi-natural population enclosures mice homozygous for the Hoxa1B1 swap were out-reproduced by controls resulting in the mutant allele being only 87.5% as frequent as the control in offspring born within enclosures. Specifically, Hoxa1B1 founders produced only 77.9% as many offspring relative to controls, as measured by homozygous pups, and a 22.1% deficiency of heterozygous offspring was also observed. These data suggest that Hoxa1 and Hoxb1 have diverged in function through either sub- or neo-functionalization and that the HoxA1 and HoxB1 proteins are not mutually interchangeable when expressed from the Hoxa1 locus. The fitness assays conducted under naturalistic conditions in this study have provided an ultimate-level assessment of the postulated equivalence of competing alleles. Characterization of these differences has provided greater understanding of the forces shaping the maintenance and diversifications of Hox genes as well as other paralogous genes. This fitness assay approach can be applied to any genetic manipulation and often provides the most sensitive way to detect functional differences.
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Affiliation(s)
- James S. Ruff
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Raed B. Saffarini
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Leda L. Ramoz
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Linda C. Morrison
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Shambralyn Baker
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Sean M. Laverty
- Department of Mathematics and Statistics, University of Central Oklahoma, Edmond, Oklahoma, United States of America
| | - Petr Tvrdik
- Department of Neurosurgery, University of Utah, Salt Lake City, Utah, United States of America
| | - Mario R. Capecchi
- Department of Human Genetics, University of Utah, Salt Lake City, UT, United States of America
| | - Wayne K. Potts
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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Abstract
Temporal lobe epilepsy (TLE) is a devastating seizure disorder that is often caused by status epilepticus (SE). Temporal lobe epilepsy can be very difficult to control with currently available antiseizure drugs, and there are currently no disease-modifying therapies that can prevent the development of TLE in those patients who are at risk. While the functional changes that occur in neurons following SE and leading to TLE have been well studied, only recently has research attention turned to the role in epileptogenesis of astrocytes, the other major cell type of the brain. Given that epilepsy is a neural circuit disorder, innovative ways to evaluate the contributions that both neurons and astrocytes make to aberrant circuit activity will be critical for the understanding of the emergent network properties that result in seizures. Recently described approaches using genetically encoded calcium-indicating proteins can be used to image dynamic calcium transients, a marker of activity in both neurons and glial cells. It is anticipated that this work will lead to novel insights into the process of epileptogenesis at the network level and may identify disease-modifying therapeutic targets that have been missed because of a largely neurocentric view of seizure generation following SE. This article is part of a Special Issue entitled "Status Epilepticus".
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Affiliation(s)
- Karen S. Wilcox
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA,Corresponding author at: Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84108, USA. Tel.: +1 801 581 4081. (K.S. Wilcox)
| | - James M. Gee
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | - Meredith B. Gibbons
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA
| | - Petr Tvrdik
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - John A. White
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA,Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
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Pozner A, Xu B, Palumbos S, Gee JM, Tvrdik P, Capecchi MR. Intracellular calcium dynamics in cortical microglia responding to focal laser injury in the PC::G5-tdT reporter mouse. Front Mol Neurosci 2015; 8:12. [PMID: 26005403 PMCID: PMC4424843 DOI: 10.3389/fnmol.2015.00012] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 04/16/2015] [Indexed: 11/13/2022] Open
Abstract
Microglia, the resident immune cells of the brain parenchyma, are highly responsive to tissue injury. Following cell damage, microglial processes redirect their motility from randomly scouting the extracellular space to specifically reaching toward the compromised tissue. While the cell morphology aspects of this defense mechanism have been characterized, the intracellular events underlying these responses remain largely unknown. Specifically, the role of intracellular Ca2+ dynamics has not been systematically investigated in acutely activated microglia due to technical difficulty. Here we used live two-photon imaging of the mouse cortex ubiquitously expressing the genetically encoded Ca2+ indicator GCaMP5G and fluorescent marker tdTomato in central nervous system microglia. We found that spontaneous Ca2+ transients in microglial somas and processes were generally low (only 4% of all microglia showing transients within 20 min), but baseline activity increased about 8-fold when the animals were treated with LPS 12 h before imaging. When challenged with focal laser injury, an additional surge in Ca2+ activity was observed in the somas and protruding processes. Notably, coherent and simultaneous Ca2+ rises in multiple microglial cells were occasionally detected in LPS-treated animals. We show that Ca2+ transients were pre-dominantly mediated via purinergic receptors. This work demonstrates the usefulness of genetically encoded Ca2+ indicators for investigation of microglial physiology.
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Affiliation(s)
- Amir Pozner
- Department of Human Genetics, University of Utah Salt Lake City, UT, USA ; Department of Chemistry, University of Utah Salt Lake City, UT, USA
| | - Ben Xu
- Department of Human Genetics, University of Utah Salt Lake City, UT, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
| | - Sierra Palumbos
- Department of Human Genetics, University of Utah Salt Lake City, UT, USA
| | - J Michael Gee
- Department of Bioengineering, University of Utah Salt Lake City, UT, USA
| | - Petr Tvrdik
- Department of Human Genetics, University of Utah Salt Lake City, UT, USA
| | - Mario R Capecchi
- Department of Human Genetics, University of Utah Salt Lake City, UT, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
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Gee JM, Gibbons MB, Taheri M, Palumbos S, Morris SC, Smeal RM, Flynn KF, Economo MN, Cizek CG, Capecchi MR, Tvrdik P, Wilcox KS, White JA. Imaging activity in astrocytes and neurons with genetically encoded calcium indicators following in utero electroporation. Front Mol Neurosci 2015; 8:10. [PMID: 25926768 PMCID: PMC4397926 DOI: 10.3389/fnmol.2015.00010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 03/23/2015] [Indexed: 11/13/2022] Open
Abstract
Complex interactions between networks of astrocytes and neurons are beginning to be appreciated, but remain poorly understood. Transgenic mice expressing fluorescent protein reporters of cellular activity, such as the GCaMP family of genetically encoded calcium indicators (GECIs), have been used to explore network behavior. However, in some cases, it may be desirable to use long-established rat models that closely mimic particular aspects of human conditions such as Parkinson's disease and the development of epilepsy following status epilepticus. Methods for expressing reporter proteins in the rat brain are relatively limited. Transgenic rat technologies exist but are fairly immature. Viral-mediated expression is robust but unstable, requires invasive injections, and only works well for fairly small genes (<5 kb). In utero electroporation (IUE) offers a valuable alternative. IUE is a proven method for transfecting populations of astrocytes and neurons in the rat brain without the strict limitations on transgene size. We built a toolset of IUE plasmids carrying GCaMP variants 3, 6s, or 6f driven by CAG and targeted to the cytosol or the plasma membrane. Because low baseline fluorescence of GCaMP can hinder identification of transfected cells, we included the option of co-expressing a cytosolic tdTomato protein. A binary system consisting of a plasmid carrying a piggyBac inverted terminal repeat (ITR)-flanked CAG-GCaMP-IRES-tdTomato cassette and a separate plasmid encoding for expression of piggyBac transposase was employed to stably express GCaMP and tdTomato. The plasmids were co-electroporated on embryonic days 13.5-14.5 and astrocytic and neuronal activity was subsequently imaged in acute or cultured brain slices prepared from the cortex or hippocampus. Large spontaneous transients were detected in slices obtained from rats of varying ages up to 127 days. In this report, we demonstrate the utility of this toolset for interrogating astrocytic and neuronal activity in the rat brain.
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Affiliation(s)
- J Michael Gee
- Neuronal Dynamics Laboratory, Department of Bioengineering, University of Utah Salt Lake City, UT, USA ; MD-PhD Program, University of Utah Salt Lake City, UT, USA
| | - Meredith B Gibbons
- Glial-Neuronal Interactions in Epilepsy Laboratory, Department of Pharmacology and Toxicology, University of Utah Salt Lake City, UT, USA ; Interdepartmental Program in Neuroscience, University of Utah Salt Lake City, UT, USA
| | - Marsa Taheri
- Neuronal Dynamics Laboratory, Department of Bioengineering, University of Utah Salt Lake City, UT, USA
| | - Sierra Palumbos
- Mario Capecchi Laboratory, Department of Human Genetics, University of Utah Salt Lake City, UT, USA
| | - S Craig Morris
- Neuronal Dynamics Laboratory, Department of Bioengineering, University of Utah Salt Lake City, UT, USA ; Mario Capecchi Laboratory, Department of Human Genetics, University of Utah Salt Lake City, UT, USA
| | - Roy M Smeal
- Glial-Neuronal Interactions in Epilepsy Laboratory, Department of Pharmacology and Toxicology, University of Utah Salt Lake City, UT, USA
| | - Katherine F Flynn
- Glial-Neuronal Interactions in Epilepsy Laboratory, Department of Pharmacology and Toxicology, University of Utah Salt Lake City, UT, USA
| | - Michael N Economo
- Neuronal Dynamics Laboratory, Department of Bioengineering, University of Utah Salt Lake City, UT, USA
| | - Christian G Cizek
- Neuronal Dynamics Laboratory, Department of Bioengineering, University of Utah Salt Lake City, UT, USA ; Mario Capecchi Laboratory, Department of Human Genetics, University of Utah Salt Lake City, UT, USA
| | - Mario R Capecchi
- Mario Capecchi Laboratory, Department of Human Genetics, University of Utah Salt Lake City, UT, USA ; Department of Human Genetics, Howard Hughes Medical Institute, University of Utah Salt Lake City, UT, USA
| | - Petr Tvrdik
- Mario Capecchi Laboratory, Department of Human Genetics, University of Utah Salt Lake City, UT, USA
| | - Karen S Wilcox
- Glial-Neuronal Interactions in Epilepsy Laboratory, Department of Pharmacology and Toxicology, University of Utah Salt Lake City, UT, USA
| | - John A White
- Neuronal Dynamics Laboratory, Department of Bioengineering, University of Utah Salt Lake City, UT, USA
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Irwin M, Greig A, Tvrdik P, Lucero MT. PACAP modulation of calcium ion activity in developing granule cells of the neonatal mouse olfactory bulb. J Neurophysiol 2014; 113:1234-48. [PMID: 25475351 DOI: 10.1152/jn.00594.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ca(2+) activity in the CNS is critical for the establishment of developing neuronal circuitry prior to and during early sensory input. In developing olfactory bulb (OB), the neuromodulators that enhance network activity are largely unknown. Here we provide evidence that pituitary adenylate cyclase-activating peptide (PACAP)-specific PAC1 receptors (PAC1Rs) expressed in postnatal day (P)2-P5 mouse OB are functional and enhance network activity as measured by increases in calcium in genetically identified granule cells (GCs). We used confocal Ca(2+) imaging of OB slices from Dlx2-tdTomato mice to visualize GABAergic GCs. To address whether the PACAP-induced Ca(2+) oscillations were direct or indirect effects of PAC1R activation, we used antagonists for the GABA receptors (GABARs) and/or glutamate receptors (GluRs) in the presence and absence of PACAP. Combined block of GABARs and GluRs yielded a 66% decrease in the numbers of PACAP-responsive cells, suggesting that 34% of OB neurons are directly activated by PACAP. Similarly, immunocytochemistry using anti-PAC1 antibody showed that 34% of OB neurons express PAC1R. Blocking either GluRs or GABARs alone indirectly showed that PACAP stimulates release of both glutamate and GABA, which activate GCs. The appearance of PACAP-induced Ca(2+) activity in immature GCs suggests a role for PACAP in GC maturation. To conclude, we find that PACAP has both direct and indirect effects on neonatal OB GABAergic cells and may enhance network activity by promoting glutamate and GABA release. Furthermore, the numbers of PACAP-responsive GCs significantly increased between P2 and P5, suggesting that PACAP-induced Ca(2+) activity contributes to neonatal OB development.
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Affiliation(s)
- Mavis Irwin
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah
| | - Ann Greig
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah
| | - Petr Tvrdik
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah; Interdepartmental Neuroscience Program, University of Utah School of Medicine, Salt Lake City, Utah; and
| | - Mary T Lucero
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah; Interdepartmental Neuroscience Program, University of Utah School of Medicine, Salt Lake City, Utah; and Department of Neuroscience and Physiology, American University of the Caribbean, Cupecoy, Sint Maarten, Netherlands Antilles
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37
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Gee JM, Smith NA, Fernandez FR, Economo MN, Brunert D, Rothermel M, Morris SC, Talbot A, Palumbos S, Ichida JM, Shepherd JD, West PJ, Wachowiak M, Capecchi MR, Wilcox KS, White JA, Tvrdik P. Imaging activity in neurons and glia with a Polr2a-based and cre-dependent GCaMP5G-IRES-tdTomato reporter mouse. Neuron 2014; 83:1058-72. [PMID: 25155958 DOI: 10.1016/j.neuron.2014.07.024] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2014] [Indexed: 11/27/2022]
Abstract
UNLABELLED New strategies for introducing genetically encoded activity indicators into animal models facilitate the investigation of nervous system function. We have developed the PC::G5-tdT mouse line that expresses the GCaMP5G calcium indicator in a Cre-dependent fashion. Instead of targeting the ROSA26 locus, we inserted the reporter cassette nearby the ubiquitously expressed Polr2a gene without disrupting locus integrity. The indicator was tagged with IRES-tdTomato to aid detection of positive cells. This reporter system is effective in a wide range of developmental and cellular contexts. We recorded spontaneous cortical calcium waves in intact awake newborns and evaluated concentration-dependent responses to odorants in the adult olfactory bulb. Moreover, PC::G5-tdT effectively reports intracellular calcium dynamics in somas and fine processes of astrocytes and microglial cells. Through electrophysiological and behavioral analyses, we determined that GCaMP5G expression had no major impact on nervous system performance. PC::G5-tdT will be instrumental for a variety of brain mapping experiments. VIDEO ABSTRACT
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Affiliation(s)
- J Michael Gee
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112; Brain Institute, University of Utah, Salt Lake City, UT 84112; MD-PhD Program, University of Utah, Salt Lake City, UT 84112
| | - Nathan A Smith
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112; Brain Institute, University of Utah, Salt Lake City, UT 84112
| | - Fernando R Fernandez
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112; Brain Institute, University of Utah, Salt Lake City, UT 84112
| | - Michael N Economo
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112; Brain Institute, University of Utah, Salt Lake City, UT 84112
| | - Daniela Brunert
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112; Brain Institute, University of Utah, Salt Lake City, UT 84112
| | - Markus Rothermel
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112; Brain Institute, University of Utah, Salt Lake City, UT 84112
| | - S Craig Morris
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112
| | - Amy Talbot
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112
| | - Sierra Palumbos
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112
| | - Jennifer M Ichida
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112
| | - Jason D Shepherd
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112
| | - Peter J West
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112
| | - Matt Wachowiak
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112; Brain Institute, University of Utah, Salt Lake City, UT 84112
| | - Mario R Capecchi
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112; Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112
| | - Karen S Wilcox
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112
| | - John A White
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112; Brain Institute, University of Utah, Salt Lake City, UT 84112.
| | - Petr Tvrdik
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112.
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Fu Y, Tvrdik P, Makki N, Machold R, Paxinos G, Watson C. The interfascicular trigeminal nucleus: a precerebellar nucleus in the mouse defined by retrograde neuronal tracing and genetic fate mapping. J Comp Neurol 2013; 521:697-708. [PMID: 22829396 DOI: 10.1002/cne.23200] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 07/18/2012] [Accepted: 07/19/2012] [Indexed: 11/06/2022]
Abstract
We have found a previously unreported precerebellar nucleus located among the emerging fibers of the motor root of the trigeminal nerve in the mouse, which we have called the interfascicular trigeminal nucleus (IF5). This nucleus had previously been named the tensor tympani part of the motor trigeminal nucleus (5TT) in rodent brain atlases, because it was thought to be a subset of small motor neurons of the motor trigeminal nucleus innervating the tensor tympani muscle. However, following injection of retrograde tracer in the cerebellum, the labeled neurons in IF5 were found to be choline acetyltransferase (ChAT) negative, indicating that they are not motor neurons. The cells of IF5 are strongly labeled in mice from Wnt1Cre and Atoh1 CreER lineage fate mapping, in common with the major precerebellar nuclei that arise from the rhombic lip and that issue mossy fibers. Analysis of sections from mouse Hoxa3, Hoxb1, and Egr2 Cre labeled lineages shows that the neurons of IF5 arise from rhombomeres caudal to rhombomere 4, most likely from rhombomeres 6-8. We conclude that IF5 is a significant precerebellar nucleus in the mouse that shares developmental gene expression characteristics with mossy fiber precerebellar nuclei that arise from the caudal rhombic lip.
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Affiliation(s)
- Yuhong Fu
- Neuroscience Research Australia, Randwick, New South Wales 2031, Australia
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39
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Gahring LC, Enioutina EY, Myers EJ, Spangrude GJ, Efimova OV, Kelley TW, Tvrdik P, Capecchi MR, Rogers SW. Nicotinic receptor alpha7 expression identifies a novel hematopoietic progenitor lineage. PLoS One 2013; 8:e57481. [PMID: 23469197 PMCID: PMC3586088 DOI: 10.1371/journal.pone.0057481] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 01/22/2013] [Indexed: 11/19/2022] Open
Abstract
How inflammatory responses are mechanistically modulated by nicotinic acetylcholine receptors (nAChR), especially by receptors composed of alpha7 (α7) subunits, is poorly defined. This includes a precise definition of cells that express α7 and how these impact on innate inflammatory responses. To this aim we used mice generated through homologous recombination that express an Ires-Cre-recombinase bi-cistronic extension of the endogenous α7 gene that when crossed with a reporter mouse expressing Rosa26-LoxP (yellow fluorescent protein (YFP)) marks in the offspring those cells of the α7 cell lineage (α7lin+). In the adult, on average 20–25 percent of the total CD45+ myeloid and lymphoid cells of the bone marrow (BM), blood, spleen, lymph nodes, and Peyers patches are α7lin+, although variability between litter mates in this value is observed. This hematopoietic α7lin+ subpopulation is also found in Sca1+cKit+ BM cells suggesting the α7 lineage is established early during hematopoiesis and the ratio remains stable in the individual thereafter as measured for at least 18 months. Both α7lin+ and α7lin– BM cells can reconstitute the immune system of naïve irradiated recipient mice and the α7lin+:α7lin– beginning ratio is stable in the recipient after reconstitution. Functionally the α7lin+:α7lin– lineages differ in response to LPS challenge. Most notable is the response to LPS as demonstrated by an enhanced production of IL-12/23(p40) by the α7lin+ cells. These studies demonstrate that α7lin+ identifies a novel subpopulation of bone marrow cells that include hematopoietic progenitor cells that can re-populate an animal’s inflammatory/immune system. These findings suggest that α7 exhibits a pleiotropic role in the hematopoietic system that includes both the direct modulation of pro-inflammatory cell composition and later in the adult the role of modulating pro-inflammatory responses that would impact upon an individual’s lifelong response to inflammation and infection.
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Affiliation(s)
- Lorise C Gahring
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Administration Medical Center, Salt Lake City, Utah, United States of America.
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Rogers SW, Tvrdik P, Capecchi MR, Gahring LC. Prenatal ablation of nicotinic receptor alpha7 cell lineages produces lumbosacral spina bifida the severity of which is modified by choline and nicotine exposure. Am J Med Genet A 2012; 158A:1135-44. [PMID: 22473653 PMCID: PMC3415211 DOI: 10.1002/ajmg.a.35372] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 02/26/2012] [Indexed: 12/29/2022]
Abstract
Lumbosacral spina bifida is a common debilitating birth defect whose multiple causes are poorly understood. Here, we provide the first genetic delineation of cholinergic nicotinic receptor alpha7 (Chrna7) expression and link the ablation of the Chrna7 cell lineage to this condition in the mouse. Using homologous recombination, an IRES-Cre bi-cistronic cassette was introduced into the 3′ noncoding region of Chrna7 (Chrna7:Cre) for identifying cell lineages expressing this gene. This lineage first appears at embryonic day E9.0 in rhombomeres 3 and 5 of the neural tube and extends to cell subsets in most tissues by E14.5. Ablation of the Chrna7:Cre cell lineage in embryos from crosses with conditionally expressed attenuated diphtheria toxin results in precise developmental defects including omphalocele (89%) and open spina bifida (SB; 80%). We hypothesized that like humans, this defect would be modified by environmental compounds not only folic acid or choline but also nicotine. Prenatal chronic oral nicotine administration substantially worsened the defect to often include the rostral neural tube. In contrast, supplementation of the maternal diet with 2% choline decreased SB prevalence to 38% and dramatically reduced the defect severity. Folic acid supplementation only trended towards a reduced SB frequency. The omphalocele was unaffected by these interventions. These studies identify the Chrna7 cell lineage as participating in posterior neuropore closure and present a novel model of lower SB that can be substantially modified by the prenatal environment. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Scott W Rogers
- Salt Lake City VA Geriatric Research, Education and Clinical Center, Salt Lake City, Utah, USA.
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Zadravec D, Tvrdik P, Guillou H, Haslam R, Kobayashi T, Napier JA, Capecchi MR, Jacobsson A. ELOVL2 controls the level of n-6 28:5 and 30:5 fatty acids in testis, a prerequisite for male fertility and sperm maturation in mice. J Lipid Res 2010; 52:245-55. [PMID: 21106902 DOI: 10.1194/jlr.m011346] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
ELOVL2 is a member of the mammalian microsomal ELOVL fatty acid enzyme family, involved in the elongation of very long-chain fatty acids including PUFAs required for various cellular functions in mammals. Here, we used ELOVL2-ablated (Elovl2(-/-)) mice to show that the PUFAs with 24-30 carbon atoms of the ω-6 family in testis are indispensable for normal sperm formation and fertility in male mice. The lack of Elovl2 was associated with a complete arrest of spermatogenesis, with seminiferous tubules displaying only spermatogonia and primary spermatocytes without further germinal cells. Furthermore, based on acyl-CoA profiling, heterozygous Elovl2(+/-) male mice exhibited haploinsufficiency, with reduced levels of C28:5 and C30:5n-6 PUFAs, which gave rise to impaired formation and function of haploid spermatides. These new insights reveal a novel mechanism involving ELOVL2-derived PUFAs in mammals and previously unrecognized roles for C28 and C30 n-6 PUFAs in male fertility. In accordance with the function suggested for ELOVL2, the Elovl2(-/-) mice show distorted levels of serum C20 and C22 PUFAs from both the n-3 and the n-6 series. However, dietary supplementation with C22:6n-3 could not restore male fertility to Elovl2(+/-) mice, suggesting that the changes in n-6 fatty acid composition seen in the testis of the Elovl2(+/-) mice, cannot be compensated by increased C22:6n-3 content.
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Affiliation(s)
- Damir Zadravec
- The Wenner-Gren Institute, Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
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Chen SK, Tvrdik P, Peden E, Cho S, Wu S, Spangrude G, Capecchi MR. Hematopoietic origin of pathological grooming in Hoxb8 mutant mice. Cell 2010; 141:775-85. [PMID: 20510925 DOI: 10.1016/j.cell.2010.03.055] [Citation(s) in RCA: 316] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Revised: 03/03/2010] [Accepted: 03/26/2010] [Indexed: 10/19/2022]
Abstract
Mouse Hoxb8 mutants show unexpected behavior manifested by compulsive grooming and hair removal, similar to behavior in humans with the obsessive-compulsive disorder spectrum disorder trichotillomania. As Hox gene disruption often has pleiotropic effects, the root cause of this behavioral deficit was unclear. Here we report that, in the brain, Hoxb8 cell lineage exclusively labels bone marrow-derived microglia. Furthermore, transplantation of wild-type bone marrow into Hoxb8 mutant mice rescues their pathological phenotype. It has been suggested that the grooming dysfunction results from a nociceptive defect, also exhibited by Hoxb8 mutant mice. However, bone marrow transplant experiments and cell type-specific disruption of Hoxb8 reveal that these two phenotypes are separable, with the grooming phenotype derived from the hematopoietic lineage and the sensory defect derived from the spinal cord cells. Immunological dysfunctions have been associated with neuropsychiatric disorders, but the causative relationships are unclear. In this mouse, a distinct compulsive behavioral disorder is associated with mutant microglia.
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Affiliation(s)
- Shau-Kwaun Chen
- Howard Hughes Medical Institute, Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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Fu Y, Tvrdik P, Makki N, Palombi O, Machold R, Paxinos G, Watson C. The precerebellar linear nucleus in the mouse defined by connections, immunohistochemistry, and gene expression. Brain Res 2009; 1271:49-59. [DOI: 10.1016/j.brainres.2009.02.068] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 02/24/2009] [Accepted: 02/25/2009] [Indexed: 01/29/2023]
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Haldar M, Karan G, Tvrdik P, Capecchi MR. Two cell lineages, myf5 and myf5-independent, participate in mouse skeletal myogenesis. Dev Cell 2008; 14:437-45. [PMID: 18331721 DOI: 10.1016/j.devcel.2008.01.002] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 11/29/2007] [Accepted: 01/02/2008] [Indexed: 01/24/2023]
Abstract
In skeletal muscle development, the myogenic regulatory factors myf5 and myoD play redundant roles in the specification and maintenance of myoblasts, whereas myf6 has a downstream role in differentiating myocytes and myofibers. It is not clear whether the redundancy between myf5 and myoD is within the same cell lineage or between distinct lineages. Using lineage tracing and conditional cell ablation in mice, we demonstrate the existence of two distinct lineages in myogenesis: a myf5 lineage and a myf5-independent lineage. Ablating the myf5 lineage is compatible with myogenesis sustained by myf5-independent, myoD-expressing myoblasts, whereas ablation of the myf6 lineage leads to an absence of all differentiated myofibers, although early myogenesis appears to be unaffected. We also demonstrate here the existence of a significant myf5 lineage within ribs that has an important role in rib development, suggested by severe rib defects upon ablating the myf5 lineage.
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Affiliation(s)
- Malay Haldar
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112, USA
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Abstract
In vertebrates, paralogous Hox genes play diverse biological roles. We examined the interchangeability of Hoxa1 and Hoxb1 in mouse development by swapping their protein-coding regions. Remarkably, the mice expressing the Hox-B1 protein from the Hoxa1 locus, and vice versa, are essentially normal. We noted, nonetheless, a specific facial nerve hypomorphism in hemizygous Hoxb1(A1/-) mice and decreased viability in homozygous Hoxa1(B1/B1) embryos. Further, we established a mouse line in which we have inserted the 107 bp Hoxb1 autoregulatory enhancer into the Hoxa1 promoter. Strikingly, the newly generated autoregulatory Hoxa1 gene can deliver the functionality of both paralogs in these mice, providing normal viability as well as proper facial nerve formation even in the Hoxb1 mutant background. This study affirms that subfunctionalization of the transcriptional regulatory elements has a principal role in the diversification of paralogous Hox genes. Moreover, we show that the ancestral vertebrate Hox1 gene can still be experimentally reconstructed.
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Affiliation(s)
- Petr Tvrdik
- Howard Hughes Medical Institute, University of Utah, 15 North 2030 East, Salt Lake City, Utah 84112, USA
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Westerberg R, Månsson JE, Golozoubova V, Shabalina IG, Backlund EC, Tvrdik P, Retterstøl K, Capecchi MR, Jacobsson A. ELOVL3 is an important component for early onset of lipid recruitment in brown adipose tissue. J Biol Chem 2005; 281:4958-68. [PMID: 16326704 DOI: 10.1074/jbc.m511588200] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During the recruitment process of brown adipose tissue, the mRNA level of the fatty acyl chain elongase Elovl3 is elevated more than 200-fold in cold-stressed mice. We have obtained Elovl3-ablated mice and report here that, although cold-acclimated Elovl3-ablated mice experienced an increased heat loss due to impaired skin barrier, they were unable to hyperrecruit their brown adipose tissue. Instead, they used muscle shivering in order to maintain body temperature. Lack of Elovl3 resulted in a transient decrease in the capacity to elongate saturated fatty acyl-CoAs into very long chain fatty acids, concomitantly with the occurrence of reduced levels of arachidic acid (C20:0) and behenic acid (C22:0) in brown adipose tissue during the initial cold stress. This effect on very long chain fatty acid synthesis could be illustrated as a decrease in the condensation activity of the elongation enzyme. In addition, warm-acclimated Elovl3-ablated mice showed diminished ability to accumulate fat and reduced metabolic capacity within the brown fat cells. This points to ELOVL3 as an important regulator of endogenous synthesis of saturated very long chain fatty acids and triglyceride formation in brown adipose tissue during the early phase of the tissue recruitment.
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Affiliation(s)
- Rolf Westerberg
- Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
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Arenkiel BR, Tvrdik P, Gaufo GO, Capecchi MR. Hoxb1 functions in both motoneurons and in tissues of the periphery to establish and maintain the proper neuronal circuitry. Genes Dev 2004; 18:1539-52. [PMID: 15198977 PMCID: PMC443517 DOI: 10.1101/gad.1207204] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Formation of neuronal circuits in the head requires the coordinated development of neurons within the central nervous system (CNS) and neural crest-derived peripheral target tissues. Hoxb1, which is expressed throughout rhombomere 4 (r4), has been shown to be required for the specification of facial branchiomotor neuron progenitors that are programmed to innervate the muscles of facial expression. In this study, we have uncovered additional roles for Hoxb1-expressing cells in the formation and maintenance of the VIIth cranial nerve circuitry. By conditionally deleting the Hoxb1 locus in neural crest, we demonstrate that Hoxb1 is also required in r4-derived neural crest to facilitate and maintain formation of the VIIth nerve circuitry. Genetic lineage analysis revealed that a significant population of r4-derived neural crest is fated to generate glia that myelinate the VIIth cranial nerve. Neural crest cultures show that the absence of Hoxb1 function does not appear to affect overall glial progenitor specification, suggesting that a later glial function is critical for maintenance of the VIIth nerve. Taken together, these results suggest that the molecular program governing the development and maintenance of the VIIth cranial nerve is dependent upon Hoxb1, both in the neural crest-derived glia and in the facial branchiomotor neurons.
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Affiliation(s)
- Benjamin R Arenkiel
- Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah 84112, USA
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Westerberg R, Tvrdik P, Undén AB, Månsson JE, Norlén L, Jakobsson A, Holleran WH, Elias PM, Asadi A, Flodby P, Toftgård R, Capecchi MR, Jacobsson A. Role for ELOVL3 and Fatty Acid Chain Length in Development of Hair and Skin Function. J Biol Chem 2004; 279:5621-9. [PMID: 14581464 DOI: 10.1074/jbc.m310529200] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Very little is known about the in vivo regulation of mammalian fatty acid chain elongation enzymes as well as the role of specific fatty acid chain length in cellular responses and developmental processes. Here, we report that the Elovl3 gene product, which belongs to a highly conserved family of microsomal enzymes involved in the formation of very long chain fatty acids, revealed a distinct expression in the skin that was restricted to the sebaceous glands and the epithelial cells of the hair follicles. By disruption of the Elovl3 gene by homologous recombination in mouse, we show that ELOVL3 participates in the formation of specific neutral lipids that are necessary for the function of the skin. The Elovl3-ablated mice displayed a sparse hair coat, the pilosebaceous system was hyperplastic, and the hair lipid content was disturbed with exceptionally high levels of eicosenoic acid (20:1). This was most prominent within the triglyceride fraction where fatty acids longer than 20 carbon atoms were almost undetectable. A functional consequence of this is that Elovl3-ablated mice exhibited a severe defect in water repulsion and increased trans-epidermal water loss.
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Affiliation(s)
- Rolf Westerberg
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
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Tvrdik P, Westerberg R, Silve S, Asadi A, Jakobsson A, Cannon B, Loison G, Jacobsson A. Role of a new mammalian gene family in the biosynthesis of very long chain fatty acids and sphingolipids. J Cell Biol 2000; 149:707-18. [PMID: 10791983 PMCID: PMC2174859 DOI: 10.1083/jcb.149.3.707] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Whereas the physiological significance of microsomal fatty acid elongation is generally appreciated, its molecular nature is poorly understood. Here, we describe tissue-specific regulation of a novel mouse gene family encoding components implicated in the synthesis of very long chain fatty acids. The Ssc1 gene appears to be ubiquitously expressed, whereas Ssc2 and Cig30 show a restricted expression pattern. Their translation products are all integral membrane proteins with five putative transmembrane domains. By complementing the homologous yeast mutants, we found that Ssc1 could rescue normal sphingolipid synthesis in the sur4/elo3 mutant lacking the ability to synthesize cerotic acid (C(26:0)). Similarly, Cig30 reverted the phenotype of the fen1/elo2 mutant that has reduced levels of fatty acids in the C(20)-C(24) range. Further, we show that Ssc1 mRNA levels were markedly decreased in the brains of myelin-deficient mouse mutants known to have very low fatty acid chain elongation activity. Conversely, the dramatic induction of Cig30 expression during brown fat recruitment coincided with elevated elongation activity. Our results strongly implicate this new mammalian gene family in tissue-specific synthesis of very long chain fatty acids and sphingolipids.
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Affiliation(s)
- P Tvrdik
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.
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Tvrdik P, Asadi A, Kozak LP, Nuglozeh E, Parente F, Nedergaard J, Jacobsson A. Cig30 and Pitx3 genes are arranged in a partially overlapping tail-to-tail array resulting in complementary transcripts. J Biol Chem 1999; 274:26387-92. [PMID: 10473596 DOI: 10.1074/jbc.274.37.26387] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mouse Cig30 gene codes for a 30-kDa membrane glycoprotein, which appears to have a role in the recruitment of brown adipose tissue. To elucidate the structure of the Cig30 gene, we have isolated a lambda phage genomic DNA clone containing the entire mouse gene and found that Cig30 consists of four exons that are spread over 4 kilobase pairs of genomic sequence. Using a fluorescence in situ hybridization assay and interspecific backcross panel mapping, we have localized the Cig30 locus to the distal region of mouse chromosome 19, between the Tlx1 and Ins1 loci. Sequencing of the corresponding lambda clone to completion revealed that the insert contained yet another gene in the opposite orientation. It turned out to be the newly identified homeobox gene Pitx3. Interestingly, the genes are very tightly linked, so that the 3' ends of their transcripts are complementary. Thus, our results provide evidence for bidirectional transcription of a several hundred base pair-long DNA region as a result of the extremely tight linkage between Cig30 and Pitx3.
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Affiliation(s)
- P Tvrdik
- The Wenner-Gren Institute, Arrhenius Laboratories F3, Stockholm University, S-106 91 Stockholm, Sweden
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