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Bearer EL, Medina CS, Uselman TW, Jacobs RE. Harnessing axonal transport to map reward circuitry: Differing brain-wide projections from medial prefrontal cortical domains. Front Cell Dev Biol 2023; 11:1278831. [PMID: 38099294 PMCID: PMC10720719 DOI: 10.3389/fcell.2023.1278831] [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: 08/17/2023] [Accepted: 09/25/2023] [Indexed: 12/17/2023] Open
Abstract
Neurons project long axons that contact other distant neurons. Neurons in the medial prefrontal cortex project into the limbic system to regulate responses to reward or threat. Diminished neural activity in prefrontal cortex is associated with loss of executive function leading to drug use, yet the specific circuitry that mediate these effects is unknown. Different regions within the medial prefrontal cortex may project to differing limbic system nuclei. Here, we exploited the cell biology of intracellular membrane trafficking, fast axonal transport, to map projections from two adjacent medial prefrontal cortical regions. We used Mn(II), a calcium analog, to trace medial prefrontal cortical projections in the living animal by magnetic resonance imaging (MRI). Mn(II), a contrast agent for MRI, enters neurons through voltage-activated calcium channels and relies on kinesin-1 and amyloid-precursor protein to transport out axons to distal destinations. Aqueous MnCl2 together with fluorescent dextran (3--5 nL) was stereotactically injected precisely into two adjacent regions of the medial prefrontal cortex: anterior cingulate area (ACA) or infralimbic/prelimbic (IL/PL) region. Projections were traced, first live by manganese-enhanced MRI (MEMRI) at four time points in 3D, and then after fixation by microscopy. Data-driven unbiased voxel-wise statistical maps of aligned normalized MR images after either ACA or IL/PL injections revealed statistically significant progression of Mn(II) over time into deeper brain regions: dorsal striatum, globus pallidus, amygdala, hypothalamus, substantia nigra, dorsal raphe and locus coeruleus. Quantitative comparisons of these distal accumulations at 24 h revealed dramatic differences between ACA and IL/PL injection groups throughout the limbic system, and most particularly in subdomains of the hypothalamus. ACA projections targeted dorsomedial nucleus of the hypothalamus, posterior part of the periventricular region and mammillary body nuclei as well as periaqueductal gray, while IL/PL projections accumulated in anterior hypothalamic areas and lateral hypothalamic nuclei as well as amygdala. As hypothalamic subsegments relay CNS activity to the body, our results suggest new concepts about mind-body relationships and specific roles of distinct yet adjacent medial prefrontal cortical segments. Our MR imaging strategy, when applied to follow other cell biological processes in the living organism, will undoubtedly lead to an expanded perspective on how minute details of cellular processes influence whole body health and wellbeing.
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Affiliation(s)
- Elaine L. Bearer
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Christopher S. Medina
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Taylor W. Uselman
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Russell E. Jacobs
- Zilkha Neurogenetic Institute, USC Keck School of Medicine, Los Angeles, CA, United States
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Bearer EL, Medina CS, Uselman TW, Jacobs RE. Harnessing axonal transport to map reward circuitry: Differing brain-wide projections from medial forebrain domains. bioRxiv 2023:2023.09.10.557059. [PMID: 38328063 PMCID: PMC10849663 DOI: 10.1101/2023.09.10.557059] [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] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Neurons project long axons that contact other distant neurons. Projections can be mapped by hijacking endogenous membrane trafficking machinery by introducing tracers. To witness functional connections in living animals, we developed a tracer detectible by magnetic resonance imaging (MRI), Mn(II). Mn(II) relies on kinesin-1 and amyloid-precursor protein to travel out axons. Within 24h, projection fields of cortical neurons can be mapped brain-wide with this technology. MnCl2 was stereotactically injected either into anterior cingulate area (ACA) or into infralimbic/prelimbic (IL/PL) of medial forebrain (n=10-12). Projections were imaged, first by manganese-enhanced MRI (MEMRI) live, and then after fixation by microscopy. MR images were collected at 100μm isotropic resolution (~5 neurons) in 3D at four time points: before and at successive time points after injections. Images were preprocessed by masking non-brain tissue, followed by intensity scaling and spatial alignment. Actual injection locations, measured from post-injection MR images, were found to be 0.06, 0.49 and 0.84mm apart between cohorts, in R-L, A-P, and D-V directions respectively. Mn(II) enhancements arrived in hindbrains by 24h in both cohorts, while co-injected rhodamine dextran was not detectible beyond immediate subcortical projections. Data-driven unbiased voxel-wise statistical maps after ACA injections revealed significant progression of Mn(II) distally into deeper brain regions: globus pallidus, dorsal striatum, amygdala, hypothalamus, substantia nigra, dorsal raphe and locus coeruleus. Accumulation was quantified as a fraction of total volume of each segment containing significantly enhanced voxels (fractional accumulation volumes), and results visualized in column graphs. Unpaired t-tests between groups of brain-wide voxel-wise intensity profiling by either region of interest (ROI) measurements or statistical parametric mapping highlighted distinct differences in distal accumulation between injection sites, with ACA projecting to periaqueductal gray and IL/PL to basolateral amygdala (p<0.001 FDR). Mn(II) distal accumulations differed dramatically between injection groups in subdomains of the hypothalamus, with ACA targeting dorsal medial, periventricular region and mammillary body nuclei, while IL/PL went to anterior hypothalamic areas and lateral hypothalamic nuclei. Given that these hypothalamic subsegments communicate activity in the central nervous system to the body, these observations describing distinct forebrain projection fields will undoubtedly lead to newer insights in mind-body relationships.
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Affiliation(s)
- E. L. Bearer
- Department of Pathology, Univ. of New Mexico Health Sciences Center, Albuquerque, NM
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - C. S. Medina
- Department of Pathology, Univ. of New Mexico Health Sciences Center, Albuquerque, NM
| | - T. W. Uselman
- Department of Pathology, Univ. of New Mexico Health Sciences Center, Albuquerque, NM
| | - R. E. Jacobs
- Zilkha Neurogenetic Institute, USC Keck School of Medicine, Los Angeles, CA
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Medina CS, Uselman TW, Barto DR, Cháves F, Jacobs RE, Bearer EL. Decoupling the Effects of the Amyloid Precursor Protein From Amyloid-β Plaques on Axonal Transport Dynamics in the Living Brain. Front Cell Neurosci 2019; 13:501. [PMID: 31849608 PMCID: PMC6901799 DOI: 10.3389/fncel.2019.00501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 08/02/2019] [Accepted: 10/22/2019] [Indexed: 11/16/2022] Open
Abstract
Amyloid precursor protein (APP) is the precursor to Aβ plaques. The cytoplasmic domain of APP mediates attachment of vesicles to molecular motors for axonal transport. In APP-KO mice, transport of Mn2+ is decreased. In old transgenic mice expressing mutated human (APPSwInd) linked to Familial Alzheimer’s Disease, with both expression of APPSwInd and plaques, the rate and destination of Mn2+ axonal transport is altered, as detected by time-lapse manganese-enhanced magnetic resonance imaging (MEMRI) of the brain in living mice. To determine the relative contribution of expression of APPSwInd versus plaque on transport dynamics, we developed a Tet-off system to decouple expression of APPSwInd from plaque, and then studied hippocampal to forebrain transport by MEMRI. Three groups of mice were compared to wild-type (WT): Mice with plaque and APPSwInd expression; mice with plaque but suppression of APPSwInd expression; and mice with APPSwInd suppressed from mating until 2 weeks before imaging with no plaque. MR images were captured before at successive time points after stereotactic injection of Mn2+ (3–5 nL) into CA3 of the hippocampus. Mice were returned to their home cage between imaging sessions so that transport would occur in the awake freely moving animal. Images of multiple mice from the three groups (suppressed or expressed) together with C57/B6J WT were aligned and processed with our automated computational pipeline, and voxel-wise statistical parametric mapping (SPM) performed. At the conclusion of MR imaging, brains were harvested for biochemistry or histopathology. Paired T-tests within-group between time points (p = 0.01 FDR corrected) support the impression that both plaque alone and APPSwInd expression alone alter transport rates and destination of Mn2+ accumulation. Expression of APPSwInd in the absence of plaque or detectable Aβ also resulted in transport defects as well as pathology of hippocampus and medial septum, suggesting two sources of pathology occur in familial Alzheimer’s disease, from toxic mutant protein as well as plaque. Alternatively mice with plaque without APPSwInd expression resemble the human condition of sporadic Alzheimer’s, and had better transport. Thus, these mice with APPSwInd expression suppressed after plaque formation will be most useful in preclinical trials.
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Affiliation(s)
- Christopher S Medina
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Taylor W Uselman
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Daniel R Barto
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Frances Cháves
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Russell E Jacobs
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.,California Institute of Technology, Pasadena, CA, United States
| | - Elaine L Bearer
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States.,California Institute of Technology, Pasadena, CA, United States
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Medina CS, Manifold-Wheeler B, Gonzales A, Bearer EL. Automated Computational Processing of 3-D MR Images of Mouse Brain for Phenotyping of Living Animals. ACTA ACUST UNITED AC 2017; 119:29A.5.1-29A.5.38. [PMID: 28678440 DOI: 10.1002/cpmb.40] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [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: 12/11/2022]
Abstract
Magnetic resonance (MR) imaging provides a method to obtain anatomical information from the brain in vivo that is not typically available by optical imaging because of this organ's opacity. MR is nondestructive and obtains deep tissue contrast with 100-µm3 voxel resolution or better. Manganese-enhanced MRI (MEMRI) may be used to observe axonal transport and localized neural activity in the living rodent and avian brain. Such enhancement enables researchers to investigate differences in functional circuitry or neuronal activity in images of brains of different animals. Moreover, once MR images of a number of animals are aligned into a single matrix, statistical analysis can be done comparing MR intensities between different multi-animal cohorts comprising individuals from different mouse strains or different transgenic animals, or at different time points after an experimental manipulation. Although preprocessing steps for such comparisons (including skull stripping and alignment) are automated for human imaging, no such automated processing has previously been readily available for mouse or other widely used experimental animals, and most investigators use in-house custom processing. This protocol describes a stepwise method to perform such preprocessing for mouse. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
| | | | - Aaron Gonzales
- University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Elaine L Bearer
- University of New Mexico Health Sciences Center, Albuquerque, New Mexico.,Division of Biology, California Institute of Technology, Pasadena, California
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Brunnquell CL, Hernandez R, Graves SA, Smit-Oistad I, Nickles RJ, Cai W, Meyerand ME, Suzuki M. Uptake and retention of manganese contrast agents for PET and MRI in the rodent brain. Contrast Media Mol Imaging 2016; 11:371-380. [PMID: 27396476 DOI: 10.1002/cmmi.1701] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 04/28/2016] [Accepted: 05/18/2016] [Indexed: 01/04/2023]
Abstract
Manganese-enhanced magnetic resonance imaging (MRI) is an established neuroimaging method for signal enhancement, tract tracing, and functional studies in rodents. Along with the increasing availability of combined positron emission tomography (PET) and MRI scanners, the recent development of the positron-emitting isotope 52 Mn has prompted interest in the use of Mn2+ as a dual-modality contrast agent. In this work, we characterized and compared the uptake of systemically delivered Mn2+ and radioactive 52 Mn2+ in the rat brain for MRI and PET, respectively. Additionally, we examined the biodistribution of two formulations of 52 Mn2+ in the rat. In MRI, maximum uptake was observed one day following delivery of the highest MnCl2 dose tested (60 mg/kg), with some brain regions showing delayed maximum enhancement 2-4 days following delivery. In PET, we observed low brain uptake after systemic delivery, with a maximum of approximately 0.2% ID/g. We also studied the effect of final formulation vehicle (saline compared with MnCl2 ) on 52 Mn2+ organ biodistribution and brain uptake. We observed that the addition of bulk Mn2+ carrier to 52 Mn2+ in solution resulted in significantly reduced 52 Mn2+ uptake in the majority of organs, including the brain. These results lay the groundwork for further development of 52 Mn PET or dual Mn-enhanced PET-MR neuroimaging in rodents, and indicate several interesting potential applications of 52 Mn PET in other organs and systems. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Reinier Hernandez
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Stephen A Graves
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Ivy Smit-Oistad
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Robert J Nickles
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Weibo Cai
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA.,Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA
| | - M Elizabeth Meyerand
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
| | - Masatoshi Suzuki
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
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Jeong KY, Kim HM, Kang JH. Investigation of the functional difference between the pathological itching and neuropathic pain-induced rat brain using manganese-enhanced MRI. Acta Radiol 2016; 57:861-8. [PMID: 26385912 DOI: 10.1177/0284185115604514] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [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: 03/18/2015] [Accepted: 08/12/2015] [Indexed: 01/17/2023]
Abstract
BACKGROUND There is a remarkable similarity in the central sensitization of itch and pain. However, the interactions between itch and pain are only partially understood. PURPOSE To investigate the functional activity of cerebral regions to provide clear information on the neuronal pathways related to both pathological itching (PI) and neuropathic pain (NP). MATERIAL AND METHODS Sprague-Dawley rats were used in this study. PI was induced via neonatal capsaicin treatment, and scratching behavior was counted. NP was induced via lumbar spinal nerve 5 (L5) ligation, and mechanical allodynia was measured. The activated cerebral regions in the control, PI, and NP rats were measured using a 4.7 T magnetic resonance imaging (MRI) system and manganese-enhanced MRI (MEMRI). Subsequently, the cerebral activation regions were identified, and the signal intensity was compared. RESULTS Cerebral activities of the PI-induced rats were found in three regions -7.10 and -4.20 mm, and two regions -2.45 mm from the bregma. In the NP-induced rats, cerebral activities were found in two regions 7.10 and -2.45 mm, and one region -4.20 mm from the bregma. Comparing the PI and NP rats, the cerebral activities were different in one region -7.10 mm and -2.45 mm, and two regions -4.20 mm from the bregma. The different regions were the midbrain area, the geniculate complex, the hypothalamic area, and the amygdala area. CONCLUSION Our MEMRI investigation indicates functionally different activity of cerebral regions due to the effect of PI or NP. These findings provide clear information of the signal transduction in the brain regarding PI or NP that share a similar neuronal pathway.
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Affiliation(s)
- Keun-Yeong Jeong
- Gachon Institute of Pharmaceutical Science, Gachon University, Incheon, Republic of Korea
| | - Hwan Mook Kim
- Gachon Institute of Pharmaceutical Science, Gachon University, Incheon, Republic of Korea
| | - Ji-Hyuk Kang
- Department of Biomedical Laboratory Science, College of Health and Medical Science, Daejeon University, Daejeon, Republic of Korea
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Jeong KY, Kim HM, Kang JH. Investigation of the functional difference between the pathological itching and neuropathic pain-induced rat brain using manganese-enhanced MRI. Acta Radiol 2015. [PMID: 26385912 DOI: 10.1177/0284185115604514.] [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] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND There is a remarkable similarity in the central sensitization of itch and pain. However, the interactions between itch and pain are only partially understood. PURPOSE To investigate the functional activity of cerebral regions to provide clear information on the neuronal pathways related to both pathological itching (PI) and neuropathic pain (NP). MATERIAL AND METHODS Sprague-Dawley rats were used in this study. PI was induced via neonatal capsaicin treatment, and scratching behavior was counted. NP was induced via lumbar spinal nerve 5 (L5) ligation, and mechanical allodynia was measured. The activated cerebral regions in the control, PI, and NP rats were measured using a 4.7 T magnetic resonance imaging (MRI) system and manganese-enhanced MRI (MEMRI). Subsequently, the cerebral activation regions were identified, and the signal intensity was compared. RESULTS Cerebral activities of the PI-induced rats were found in three regions -7.10 and -4.20 mm, and two regions -2.45 mm from the bregma. In the NP-induced rats, cerebral activities were found in two regions 7.10 and -2.45 mm, and one region -4.20 mm from the bregma. Comparing the PI and NP rats, the cerebral activities were different in one region -7.10 mm and -2.45 mm, and two regions -4.20 mm from the bregma. The different regions were the midbrain area, the geniculate complex, the hypothalamic area, and the amygdala area. CONCLUSION Our MEMRI investigation indicates functionally different activity of cerebral regions due to the effect of PI or NP. These findings provide clear information of the signal transduction in the brain regarding PI or NP that share a similar neuronal pathway.
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Affiliation(s)
- Keun-Yeong Jeong
- Gachon Institute of Pharmaceutical Science, Gachon University, Incheon, Republic of Korea
| | - Hwan Mook Kim
- Gachon Institute of Pharmaceutical Science, Gachon University, Incheon, Republic of Korea
| | - Ji-Hyuk Kang
- Department of Biomedical Laboratory Science, College of Health and Medical Science, Daejeon University, Daejeon, Republic of Korea
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Lewis CM, Graves SA, Hernandez R, Valdovinos HF, Barnhart TE, Cai W, Meyerand ME, Nickles RJ, Suzuki M. ⁵²Mn production for PET/MRI tracking of human stem cells expressing divalent metal transporter 1 (DMT1). Am J Cancer Res 2015; 5:227-39. [PMID: 25553111 PMCID: PMC4279187 DOI: 10.7150/thno.10185] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/22/2014] [Indexed: 12/26/2022] Open
Abstract
There is a growing demand for long-term in vivo stem cell imaging for assessing cell therapy techniques and guiding therapeutic decisions. This work develops the production of 52Mn and establishes proof of concept for the use of divalent metal transporter 1 (DMT1) as a positron emission tomography (PET) and magnetic resonance imaging (MRI) reporter gene for stem cell tracking in the rat brain. 52Mn was produced via proton irradiation of a natural chromium target. In a comparison of two 52Mn separation methods, solvent-solvent extraction was preferred over ion exchange chromatography because of reduced chromium impurities and higher 52Mn recovery. In vitro uptake of Mn-based PET and MRI contrast agents (52Mn2+ and Mn2+, respectively) was enhanced in DMT1 over-expressing human neural progenitor cells (hNPC-DMT1) compared to wild-type control cells (hNPC-WT). After cell transplantation in the rat striatum, increased uptake of Mn-based contrast agents in grafted hNPC-DMT1 was detected in in vivo manganese-enhanced MRI (MEMRI) and ex vivo PET and autoradiography. These initial studies indicate that this approach holds promise for dual-modality PET/MR tracking of transplanted stem cells in the central nervous system and prompt further investigation into the clinical applicability of this technique.
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