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He XF, Yang XF, Li G, Zhao Y, Luo J, Xu JH, Zheng HQ, Zhang LY, Hu XQ. Physical Exercise Improves the Neuronal Function in Ischemic Stroke Via Microglial CB 2R/P2Y12 Signaling. Mol Neurobiol 2024:10.1007/s12035-024-04391-2. [PMID: 39066973 DOI: 10.1007/s12035-024-04391-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 07/21/2024] [Indexed: 07/30/2024]
Abstract
Physical exercise (PE) may be the single most important and accessible lifestyle habit throughout life, it inhibits the neuroinflammatory response and protects the brain against damage. As the innate cells in brain, microglia undergo morphological and functional changes to communicate with neurons protecting the neurons from injury. Herein, aiming at exploring the effects of PE on the communication between microglia-neuron during acute ischemic cerebral infarction, we carried out running wheel training before the conduction of transient middle cerebral artery occlusion (tMCAO) in C57BL/6 J and Cx3cr1-GFP mice. We found that microglial P2Y12 expression in the peri-infarct area was decreased, microglial dynamics and microglia-neuron communications were impaired, using in vivo two-photon imaging. PE up-regulated the microglial P2Y12 expression, increased the microglial dynamics, and promoted the contacts of microglia with neurons. As a result, PE inhibited neuronal Ca2+ overloads and protected against damage of the neuronal mitochondria in acute tMCAO. Mechanistically, PE increased the cannabinoid receptor 2 (CB2R) in microglia, promoted the phosphorylation of Nrf2 (NF-E2-related factor 2) at ser-344, increased the transcription factor level of Mafk, and up-regulated the level of P2Y12, whereby PE increased the levels of CB2R to promote microglia-neuron contacts to monitor and protect neuronal function.
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Affiliation(s)
- Xiao-Fei He
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630, Guangdong, China
| | - Xiao-Feng Yang
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630, Guangdong, China
| | - Ge Li
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, 510663, Guangdong, China
| | - Yun Zhao
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630, Guangdong, China
| | - Jing Luo
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630, Guangdong, China
| | - Jing-Hui Xu
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630, Guangdong, China
| | - Hai-Qing Zheng
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630, Guangdong, China
| | - Li-Ying Zhang
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630, Guangdong, China.
| | - Xi-Quan Hu
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630, Guangdong, China.
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Li J, Yang F, Zhan F, Estin J, Iyer A, Zhao M, Niemeyer JE, Luo P, Li D, Lin W, Liou JY, Ma H, Schwartz TH. Mesoscopic mapping of hemodynamic responses and neuronal activity during pharmacologically induced interictal spikes in awake and anesthetized mice. J Cereb Blood Flow Metab 2024; 44:911-924. [PMID: 38230631 PMCID: PMC11318398 DOI: 10.1177/0271678x241226742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 12/14/2023] [Accepted: 12/20/2023] [Indexed: 01/18/2024]
Abstract
Imaging hemodynamic responses to interictal spikes holds promise for presurgical epilepsy evaluations. Understanding the hemodynamic response function is crucial for accurate interpretation. Prior interictal neurovascular coupling data primarily come from anesthetized animals, impacting reliability. We simultaneously monitored calcium fluctuations in excitatory neurons, hemodynamics, and local field potentials (LFP) during bicuculline-induced interictal events in both isoflurane-anesthetized and awake mice. Isoflurane significantly affected LFP amplitude but had little impact on the amplitude and area of the calcium signal. Anesthesia also dramatically blunted the amplitude and latency of the hemodynamic response, although not its area of spread. Cerebral blood volume change provided the best spatial estimation of excitatory neuronal activity in both states. Targeted silencing of the thalamus in awake mice failed to recapitulate the impact of anesthesia on hemodynamic responses suggesting that isoflurane's interruption of the thalamocortical loop did not contribute either to the dissociation between the LFP and the calcium signal nor to the alterations in interictal neurovascular coupling. The blood volume increase associated with interictal spikes represents a promising mapping signal in both the awake and anesthetized states.
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Affiliation(s)
- Jing Li
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Fan Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Fengrui Zhan
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Joshua Estin
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Aditya Iyer
- Department of Anesthesiology, Weill Cornell Medicine, New York, USA
| | - Mingrui Zhao
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - James E Niemeyer
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Peijuan Luo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Dan Li
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Weihong Lin
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Jyun-you Liou
- Department of Anesthesiology, Weill Cornell Medicine, New York, USA
| | - Hongtao Ma
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Theodore H Schwartz
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
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Gedeon JY, Pineda-Farias JB, Gold MS. In-Vivo Calcium Imaging of Sensory Neurons in the Rat Trigeminal Ganglion. J Vis Exp 2024:10.3791/65978. [PMID: 38407223 PMCID: PMC11139451 DOI: 10.3791/65978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024] Open
Abstract
Genetically encoded calcium indicators (GECIs) enable imaging techniques to monitor changes in intracellular calcium in targeted cell populations. Their large signal-to-noise ratio makes GECIs a powerful tool for detecting stimulus-evoked activity in sensory neurons. GECIs facilitate population-level analysis of stimulus encoding with the number of neurons that can be studied simultaneously. This population encoding is most appropriately done in vivo. Dorsal root ganglia (DRG), which house the soma of sensory neurons innervating somatic and visceral structures below the neck, are used most extensively for in vivo imaging because these structures are accessed relatively easily. More recently, this technique was used in mice to study sensory neurons in the trigeminal ganglion (TG) that innervate oral and craniofacial structures. There are many reasons to study TG in addition to DRG, including the long list of pain syndromes specific to oral and craniofacial structures that appear to reflect changes in sensory neuron activity, such as trigeminal neuralgia. Mice are used most extensively in the study of DRG and TG neurons because of the availability of genetic tools. However, with differences in size, ease of handling, and potentially important species differences, there are reasons to study rat rather than mouse TG neurons. Thus, we developed an approach for imaging rat TG neurons in vivo. We injected neonatal pups (p2) intraperitoneally with an AAV encoding GCaMP6s, resulting in >90% infection of both TG and DRG neurons. TG was visualized in the adult following craniotomy and decortication, and changes in GCaMP6s fluorescence were monitored in TG neurons following stimulation of mandibular and maxillary regions of the face. We confirmed that increases in fluorescence were stimulus-evoked with peripheral nerve block. While this approach has many potential uses, we are using it to characterize the subpopulation(s) of TG neurons changed following peripheral nerve injury.
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Affiliation(s)
- Jeremy Y Gedeon
- Center for Neuroscience at the University of Pittsburgh; Department of Neurobiology, University of Pittsburgh School of Medicine; Pittsburgh Center for Pain Research, University of Pittsburgh
| | - Jorge Baruch Pineda-Farias
- Department of Neurobiology, University of Pittsburgh School of Medicine; Pittsburgh Center for Pain Research, University of Pittsburgh
| | - Michael S Gold
- Department of Neurobiology, University of Pittsburgh School of Medicine; Pittsburgh Center for Pain Research, University of Pittsburgh;
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Guo T, Liu J, Chen L, Bian Z, Zheng G, Feng B. Sex differences in zymosan-induced behavioral visceral hypersensitivity and colorectal afferent sensitization. Am J Physiol Gastrointest Liver Physiol 2024; 326:G133-G146. [PMID: 38050686 PMCID: PMC11208018 DOI: 10.1152/ajpgi.00081.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 12/06/2023]
Abstract
Sex differences in visceral nociception have been reported in clinical and preclinical studies, but the potential differences in sensory neural encoding of the colorectum between males and females are not well understood. In this study, we systematically assessed sex differences in colorectal neural encoding by conducting high-throughput optical recordings in intact dorsal root ganglia (DRGs) from control and visceral hypersensitive mice. We found an apparent sex difference in zymosan-induced behavioral visceral hypersensitivity: enhanced visceromotor responses to colorectal distension were observed only in male mice, not in female mice. In addition, a higher number of mechanosensitive colorectal afferents were identified per mouse in the zymosan-treated male group than in the saline-treated male group, whereas the mechanosensitive afferents identified per mouse were comparable between the zymosan- and saline-treated female groups. The increased number of identified afferents in zymosan-treated male mice was predominantly from thoracolumbar (TL) innervation, which agrees with the significant increase in the TL afferent proportion in the zymosan group as compared with the control group in male mice. In contrast, female mice showed no difference in the proportion of colorectal neurons between saline- and zymosan-treated groups. Our results revealed a significant sex difference in colorectal afferent innervation and sensitization in the context of behavioral visceral hypersensitivity, which could drive differential clinical symptoms in male and female patients.NEW & NOTEWORTHY We used high-throughput GCaMP6f recordings to study 2,275 mechanosensitive colorectal afferents in mice. Our results revealed significant sex differences in the zymosan-induced behavioral visceral hypersensitivity, which were present in male but not female mice. Male mice also showed sensitization of colorectal afferents in the thoracolumbar pathway, whereas female mice did not. These findings highlight sex differences in sensory neural anatomy and function of the colorectum, with implications for sex-specific therapies for treating visceral pain.
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Affiliation(s)
- Tiantian Guo
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States
| | - Jia Liu
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States
| | - Longtu Chen
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States
| | - Zichao Bian
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States
| | - Guoan Zheng
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States
| | - Bin Feng
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States
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Zhang Y, Zhang Y, Shen C, Hao S, Duan W, Liu L, Wei H. Ionizing radiation alters functional neurotransmission in Drosophila larvae. Front Cell Neurosci 2023; 17:1151489. [PMID: 37484822 PMCID: PMC10357008 DOI: 10.3389/fncel.2023.1151489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
Introduction Patients undergoing cranial ionizing radiation therapy for brain malignancies are at increased risk of long-term neurocognitive decline, which is poorly understood and currently untreatable. Although the molecular pathogenesis has been intensively researched in many organisms, whether and how ionizing radiation alters functional neurotransmission remains unknown. This is the first study addressing physiological changes in neurotransmission after ionizing radiation exposure. Methods To elucidate the cellular mechanisms of radiation damage, using calcium imaging, we analyzed the effects of ionizing radiation on the neurotransmitter-evoked responses of prothoracicotropic hormone (PTTH)-releasing neurons in Drosophila larvae, which play essential roles in normal larval development. Results The neurotransmitters dopamine and tyramine decreased intracellular calcium levels of PTTH neurons in a dose-dependent manner. In gamma irradiated third-instar larvae, a dose of 25 Gy increased the sensitivity of PTTH neurons to dopamine and tyramine, and delayed development, possibly in response to abnormal functional neurotransmission. This irradiation level did not affect the viability and arborization of PTTH neurons and successful survival to adulthood. Exposure to a 40-Gy dose of gamma irradiation decreased the neurotransmitter sensitivity, physiological viability and axo-dendritic length of PTTH neurons. These serious damages led to substantial developmental delays and a precipitous reduction in the percentage of larvae that survived to adulthood. Our results demonstrate that gamma irradiation alters neurotransmitter-evoked responses, indicating synapses are vulnerable targets of ionizing radiation. Discussion The current study provides new insights into ionizing radiation-induced disruption of physiological neurotransmitter signaling, which should be considered in preventive therapeutic interventions to reduce risks of neurological deficits after photon therapy.
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Affiliation(s)
- Yi Zhang
- North China Research Institute of Electro-Optics, Beijing, China
| | - Yihao Zhang
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Cong Shen
- China Electronics Technology Group Corporation No. 45 Research Institute, Beijing, China
| | - Shun Hao
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Wenlan Duan
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Li Liu
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Hongying Wei
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
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6
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Akbar L, Castillo VCG, Olorocisimo JP, Ohta Y, Kawahara M, Takehara H, Haruta M, Tashiro H, Sasagawa K, Ohsawa M, Akay YM, Akay M, Ohta J. Multi-Region Microdialysis Imaging Platform Revealed Dorsal Raphe Nucleus Calcium Signaling and Serotonin Dynamics during Nociceptive Pain. Int J Mol Sci 2023; 24:ijms24076654. [PMID: 37047627 PMCID: PMC10094999 DOI: 10.3390/ijms24076654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/20/2023] [Accepted: 03/22/2023] [Indexed: 04/05/2023] Open
Abstract
In this research, we combined our ultralight micro-imaging device for calcium imaging with microdialysis to simultaneously visualize neural activity in the dorsal raphe nucleus (DRN) and measure serotonin release in the central nucleus of the amygdala (CeA) and the anterior cingulate cortex (ACC). Using this platform, we observed brain activity following nociception induced by formalin injection in the mouse’s hind paw. Our device showed that DRN fluorescence intensity increased after formalin injection, and the increase was highly correlated with the elevation in serotonin release in both the CeA and ACC. The increase in calcium fluorescence intensity occurred during the acute and inflammatory phases, which suggests the biphasic response of nociceptive pain. Furthermore, we found that the increase in fluorescence intensity was positively correlated with mouse licking behavior. Lastly, we compared the laterality of pain stimulation and found that DRN fluorescence activity was higher for contralateral stimulation. Microdialysis showed that CeA serotonin concentration increased only after contralateral stimulation, while ACC serotonin release responded bilaterally. In conclusion, our study not only revealed the inter-regional serotonergic connection among the DRN, the CeA, and the ACC, but also demonstrated that our device is feasible for multi-site implantation in conjunction with a microdialysis system, allowing the simultaneous multi-modal observation of different regions in the brain.
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Affiliation(s)
- Latiful Akbar
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Virgil Christian Garcia Castillo
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Joshua Philippe Olorocisimo
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Yasumi Ohta
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Mamiko Kawahara
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Hironari Takehara
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Makito Haruta
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Hiroyuki Tashiro
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
- Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Kiyotaka Sasagawa
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Masahiro Ohsawa
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8601, Japan
| | - Yasemin M. Akay
- Biomedical Engineering Department, University of Houston, 3517 Cullen Blvd, Houston, TX 77204, USA
| | - Metin Akay
- Biomedical Engineering Department, University of Houston, 3517 Cullen Blvd, Houston, TX 77204, USA
| | - Jun Ohta
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
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Shannonhouse J, Gomez R, Son H, Zhang Y, Kim YS. In Vivo Calcium Imaging of Neuronal Ensembles in Networks of Primary Sensory Neurons in Intact Dorsal Root Ganglia. J Vis Exp 2023:10.3791/64826. [PMID: 36847407 PMCID: PMC10785773 DOI: 10.3791/64826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
Ca2+ imaging can be used as a proxy for cellular activity, including action potentials and various signaling mechanisms involving Ca2+ entry into the cytoplasm or the release of intracellular Ca2+ stores. Pirt-GCaMP3-based Ca2+ imaging of primary sensory neurons of the dorsal root ganglion (DRG) in mice offers the advantage of simultaneous measurement of a large number of cells. Up to 1,800 neurons can be monitored, allowing neuronal networks and somatosensory processes to be studied as an ensemble in their normal physiological context at a populational level in vivo. The large number of neurons monitored allows the detection of activity patterns that would be challenging to detect using other methods. Stimuli can be applied to the mouse hindpaw, allowing the direct effects of stimuli on the DRG neuron ensemble to be studied. The number of neurons producing Ca2+ transients as well as the amplitude of Ca2+ transients indicates sensitivity to specific sensory modalities. The diameter of neurons provides evidence of activated fiber types (non-noxious mechano vs. noxious pain fibers, Aβ, Aδ, and C fibers). Neurons expressing specific receptors can be genetically labeled with td-Tomato and specific Cre recombinases together with Pirt-GCaMP. Therefore, Pirt-GCaMP3 Ca2+ imaging of DRG provides a powerful tool and model for the analysis of specific sensory modalities and neuron subtypes acting as an ensemble at the populational level to study pain, itch, touch, and other somatosensory signals.
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Affiliation(s)
- John Shannonhouse
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio
| | - Ruben Gomez
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio
| | - Hyeonwi Son
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio
| | - Yan Zhang
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio
| | - Yu Shin Kim
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio; Programs in Integrated Biomedical Sciences, Translational Sciences, Biomedical Engineering, Radiological Sciences, University of Texas Health Science Center at San Antonio;
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Kempmann A, Gensch T, Offenhäusser A, Tihaa I, Maybeck V, Balfanz S, Baumann A. The Functional Characterization of GCaMP3.0 Variants Specifically Targeted to Subcellular Domains. Int J Mol Sci 2022; 23:ijms23126593. [PMID: 35743038 PMCID: PMC9223625 DOI: 10.3390/ijms23126593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/31/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022] Open
Abstract
Calcium (Ca2+) ions play a pivotal role in physiology and cellular signaling. The intracellular Ca2+ concentration ([Ca2+]i) is about three orders of magnitude lower than the extracellular concentration, resulting in a steep transmembrane concentration gradient. Thus, the spatial and the temporal dynamics of [Ca2+]i are ideally suited to modulate Ca2+-mediated cellular responses to external signals. A variety of highly sophisticated methods have been developed to gain insight into cellular Ca2+ dynamics. In addition to electrophysiological measurements and the application of synthetic dyes that change their fluorescent properties upon interaction with Ca2+, the introduction and the ongoing development of genetically encoded Ca2+ indicators (GECI) opened a new era to study Ca2+-driven processes in living cells and organisms. Here, we have focused on one well-established GECI, i.e., GCaMP3.0. We have systematically modified the protein with sequence motifs, allowing localization of the sensor in the nucleus, in the mitochondrial matrix, at the mitochondrial outer membrane, and at the plasma membrane. The individual variants and a cytosolic version of GCaMP3.0 were overexpressed and purified from E. coli cells to study their biophysical properties in solution. All versions were examined to monitor Ca2+ signaling in stably transfected cell lines and in primary cortical neurons transduced with recombinant Adeno-associated viruses (rAAV). In this comparative study, we provide evidence for a robust approach to reliably trace Ca2+ signals at the (sub)-cellular level with pronounced temporal resolution.
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Affiliation(s)
- Annika Kempmann
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Thomas Gensch
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Andreas Offenhäusser
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Irina Tihaa
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Vanessa Maybeck
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Sabine Balfanz
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Arnd Baumann
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
- Correspondence: ; Tel.: +49-2461-614014
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Hartung JE, Moy JK, Loeza-Alcocer E, Nagarajan V, Jostock R, Christoph T, Schroeder W, Gold MS. Voltage-gated calcium currents in human dorsal root ganglion neurons. Pain 2022; 163:e774-e785. [PMID: 34510139 PMCID: PMC8882208 DOI: 10.1097/j.pain.0000000000002465] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/10/2021] [Indexed: 11/25/2022]
Abstract
ABSTRACT Voltage-gated calcium channels in sensory neurons underlie processes ranging from neurotransmitter release to gene expression and remain a therapeutic target for the treatment of pain. Yet virtually all we know about voltage-gated calcium channels has been obtained through the study of rodent sensory neurons and heterologously expressed channels. To address this, high voltage-activated (HVA) Ca2+ currents in dissociated human and rat dorsal root ganglion neurons were characterized with whole-cell patch clamp techniques. The HVA currents from both species shared basic biophysical and pharmacological properties. However, HVA currents in human neurons differed from those in the rat in at least 3 potentially important ways: (1) Ca2+ current density was significantly smaller, (2) the proportion of nifedipine-sensitive currents was far greater, and (3) a subpopulation of human neurons displayed relatively large constitutive current inhibition. These results highlight the need to for the study of native proteins in their native environment before initiating costly clinical trials.
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Affiliation(s)
- Jane E Hartung
- University of Pittsburgh School of Medicine, Department of Neurobiology, PA, USA
| | - Jamie K Moy
- University of Pittsburgh School of Medicine, Department of Neurobiology, PA, USA
| | | | - Vidhya Nagarajan
- University of Pittsburgh School of Medicine, Department of Neurobiology, PA, USA
| | | | | | | | - Michael S Gold
- University of Pittsburgh School of Medicine, Department of Neurobiology, PA, USA
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10
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Réaux-Le-Goazigo A, Beliard B, Delay L, Rahal L, Claron J, Renaudin N, Rivals I, Thibaut M, Nouhoum M, Deffieux T, Tanter M, Pezet S. Ultrasound localization microscopy and functional ultrasound imaging reveal atypical features of the trigeminal ganglion vasculature. Commun Biol 2022; 5:330. [PMID: 35393515 PMCID: PMC8989975 DOI: 10.1038/s42003-022-03273-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 03/15/2022] [Indexed: 12/26/2022] Open
Abstract
The functional imaging within the trigeminal ganglion (TG) is highly challenging due to its small size and deep localization. This study combined a methodological framework able to dive into the rat trigeminal nociceptive system by jointly providing 1) imaging of the TG blood vasculature at microscopic resolution, and 2) the measurement of hemodynamic responses evoked by orofacial stimulations in anesthetized rats. Despite the small number of sensory neurons within the TG, functional ultrasound imaging was able to image and quantify a strong and highly localized hemodynamic response in the ipsilateral TG, evoked not only by mechanical or chemical stimulations of corneal nociceptive fibers, but also by cutaneous mechanical stimulations of the ophthalmic and maxillary orofacial regions using a von Frey hair. The in vivo quantitative imaging of the TG’s vasculature using ultrasound localization microscopy combined with in toto labelling reveals particular features of the vascularization of the area containing the sensory neurons, that are likely the origin of this strong vaso-trigeminal response. This innovative imaging approach opens the path for future studies on the mechanisms underlying changes in trigeminal local blood flow and evoked hemodynamic responses, key mechanisms for the understanding and treatment of debilitating trigeminal pain conditions. Visualisation of rat trigeminal ganglia activation during ophthalmic or maxillary nociceptive stimulations shows atypical tortuous vascularisation and a somatotopic hemodynamic response.
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Affiliation(s)
| | - Benoit Beliard
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Lauriane Delay
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Line Rahal
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Julien Claron
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Noémi Renaudin
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Isabelle Rivals
- Equipe de Statistique Appliquée, ESPCI Paris, PSL Research University, UMRS 1158, 10 rue Vauquelin, 75005, Paris, France
| | - Miguel Thibaut
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Mohamed Nouhoum
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France.,Iconeus, 27 Rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Thomas Deffieux
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Mickael Tanter
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Sophie Pezet
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France.
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11
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Khare P, Dave KM, Kamte YS, Manoharan MA, O'Donnell LA, Manickam DS. Development of Lipidoid Nanoparticles for siRNA Delivery to Neural Cells. AAPS J 2021; 24:8. [PMID: 34873640 PMCID: PMC8648339 DOI: 10.1208/s12248-021-00653-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/28/2021] [Indexed: 01/24/2023] Open
Abstract
Lipidoid nanoparticles (LNPs) are the delivery platform in Onpattro, the first FDA-approved siRNA drug. LNPs are also the carriers in the Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines. While these applications have demonstrated that LNPs effectively deliver nucleic acids to hepatic and muscle cells, it is unclear if LNPs could be used for delivery of siRNA to neural cells, which are notoriously challenging delivery targets. Therefore, the purpose of this study was to determine if LNPs could efficiently deliver siRNA to neurons. Because of their potential delivery utility in either applications for the central nervous system and the peripheral nervous system, we used both cortical neurons and sensory neurons. We prepared siRNA-LNPs using C12-200, a benchmark ionizable cationic lipidoid along with helper lipids. We demonstrated using dynamic light scattering that the inclusion of both siRNA and PEG-lipid provided a stabilizing effect to the LNP particle diameters and polydispersity indices by minimizing aggregation. We found that siRNA-LNPs were safely tolerated by primary dorsal root ganglion neurons. Flow cytometry analysis revealed that Cy5 siRNA delivered via LNPs into rat primary cortical neurons showed uptake levels similar to Lipofectamine RNAiMAX-the gold standard commercial transfection agent. However, LNPs demonstrated a superior safety profile, whereas the Lipofectamine-mediated uptake was concomitant with significant toxicity. Fluorescence microscopy demonstrated a time-dependent increase in the uptake of LNP-delivered Cy5 siRNA in a human cortical neuron cell line. Overall, our results suggest that LNPs are a viable platform that can be optimized for delivery of therapeutic siRNAs to neural cells.
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Affiliation(s)
- Purva Khare
- Graduate School of Pharmaceutical Sciences, Duquesne University, 453 Mellon Hall, 600 Forbes Avenue, Pittsburgh, Pennsylvania, 15282, USA
| | - Kandarp M Dave
- Graduate School of Pharmaceutical Sciences, Duquesne University, 453 Mellon Hall, 600 Forbes Avenue, Pittsburgh, Pennsylvania, 15282, USA
| | - Yashika S Kamte
- Graduate School of Pharmaceutical Sciences, Duquesne University, 453 Mellon Hall, 600 Forbes Avenue, Pittsburgh, Pennsylvania, 15282, USA
| | | | - Lauren A O'Donnell
- Graduate School of Pharmaceutical Sciences, Duquesne University, 453 Mellon Hall, 600 Forbes Avenue, Pittsburgh, Pennsylvania, 15282, USA
| | - Devika S Manickam
- Graduate School of Pharmaceutical Sciences, Duquesne University, 453 Mellon Hall, 600 Forbes Avenue, Pittsburgh, Pennsylvania, 15282, USA.
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12
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Crawford J, Liu S, Tao F. A Multidisciplinary Approach to Simultaneously Monitoring Real-Time Neuronal Activity and Pain Behaviors During Optogenetic Stimulation of Brain Neurons in Freely Moving Mice. J Pain Res 2021; 14:3503-3509. [PMID: 34785947 PMCID: PMC8590449 DOI: 10.2147/jpr.s334256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 10/09/2021] [Indexed: 11/23/2022] Open
Abstract
Background Highlighted by the current opioid epidemic, identifying novel therapies to treat chronic trigeminal neuropathic pain is a critical need. To develop these treatments, it is necessary to have viable targets in the brain to act on. Historically, neural tracing studies have been extremely useful in determining connections between brain areas but do not provide information about the functionality of these connections. Combining optogenetics and behavioral observation allows researchers to determine whether a particular brain area is involved in the regulation of such behavior. The addition of multi-channel electrophysiological recording provides information on real-time neuronal activity in the specific neuronal pathway. Methods Male C57/BL/6J mice (8-week-old) underwent either chronic constriction injury of infraorbital nerve (CCI-ION) or a sham surgery and were injected with either channelrhodopsin (ChR2) or a control virus in the hypothalamic A11 nucleus. Two weeks after CCI-ION, they were tested in real-time place preference (RTPP), while neuronal activity in the spinal trigeminal nucleus caudalis (Sp5C) was recorded. Results Optogenetic excitation of the A11 neurons results in more time spent in the stimulation chamber during RTPP testing. Additionally, stimulation of the A11 results in a greater number of neuronal activity increase in the Sp5C in animals with the injection of AAV carrying ChR2 compared to animals injected with a control virus or that underwent a sham surgery. Conclusion In vivo multi-channel electrophysiological recording, optogenetic stimulation, and behavioral observation can be combined in a mouse model of chronic trigeminal neuropathic pain to validate brain areas involved in the modulation of such pain.
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Affiliation(s)
- Joshua Crawford
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX, 75246, USA
| | - Sufang Liu
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX, 75246, USA
| | - Feng Tao
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX, 75246, USA
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13
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Reported Benefits of Low-Dose Naltrexone Appear to Be Independent of the Endogenous Opioid System Involving Proopiomelanocortin Neurons and β-Endorphin. eNeuro 2021; 8:ENEURO.0087-21.2021. [PMID: 34031099 PMCID: PMC8211470 DOI: 10.1523/eneuro.0087-21.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 05/08/2021] [Accepted: 05/14/2021] [Indexed: 11/25/2022] Open
Abstract
Naltrexone is an opioid receptor antagonist approved for the treatment of alcohol and opioid use disorders at doses of 50–150 mg/d. Naltrexone has also been prescribed at much lower doses (3–6 mg/d) for the off-label treatment of inflammation and pain. Currently, a compelling mechanistic explanation for the reported efficacy of low-dose naltrexone (LDN) is lacking and none of the proposed mechanisms can explain patient reports of improved mood and sense of well-being. Here, we examined the possibility that LDN might alter the activity of the endogenous opioid system involving proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARH) in male and female mice. Known actions of POMC neurons could account for changes in pain perception and mood. However, using electrophysiologic, imaging and peptide measurement approaches, we found no evidence for such a mechanism. LDN did not change the sensitivity of opioid receptors regulating POMC neurons, the production of the β-endorphin precursor Pomc mRNA, nor the release of β-endorphin into plasma. Spontaneous postsynaptic currents (sPSCs) onto POMC neurons were slightly decreased after LDN treatment and GCaMP fluorescent signal, a proxy for intracellular calcium levels, was slightly increased. However, LDN treatment did not appear to change POMC neuron firing rate, resting membrane potential, nor action potential threshold. Therefore, LDN appears to have only slight effects on POMC neurons that do not translate to changes in intrinsic excitability or baseline electrical activity and mechanisms beyond POMC neurons and altered opioid receptor sensitivity should continue to be explored.
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14
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Bian Z, Guo T, Jiang S, Chen L, Liu J, Zheng G, Feng B. High-Throughput Functional Characterization of Visceral Afferents by Optical Recordings From Thoracolumbar and Lumbosacral Dorsal Root Ganglia. Front Neurosci 2021; 15:657361. [PMID: 33776645 PMCID: PMC7991386 DOI: 10.3389/fnins.2021.657361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 02/22/2021] [Indexed: 12/27/2022] Open
Abstract
Functional understanding of visceral afferents is important for developing the new treatment to visceral hypersensitivity and pain. The sparse distribution of visceral afferents in dorsal root ganglia (DRGs) has challenged conventional electrophysiological recordings. Alternatively, Ca2+ indicators like GCaMP6f allow functional characterization by optical recordings. Here we report a turnkey microscopy system that enables simultaneous Ca2+ imaging at two parallel focal planes from intact DRG. By using consumer-grade optical components, the microscopy system is cost-effective and can be made broadly available without loss of capacity. It records low-intensity fluorescent signals at a wide field of view (1.9 × 1.3 mm) to cover a whole mouse DRG, with a high pixel resolution of 0.7 micron/pixel, a fast frame rate of 50 frames/sec, and the capability of remote focusing without perturbing the sample. The wide scanning range (100 mm) of the motorized sample stage allows convenient recordings of multiple DRGs in thoracic, lumbar, and sacral vertebrae. As a demonstration, we characterized mechanical neural encoding of visceral afferents innervating distal colon and rectum (colorectum) in GCaMP6f mice driven by VGLUT2 promotor. A post-processing routine is developed for conducting unsupervised detection of visceral afferent responses from GCaMP6f recordings, which also compensates the motion artifacts caused by mechanical stimulation of the colorectum. The reported system offers a cost-effective solution for high-throughput recordings of visceral afferent activities from a large volume of DRG tissues. We anticipate a wide application of this microscopy system to expedite our functional understanding of visceral innervations.
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Affiliation(s)
- Zichao Bian
- Department of Biomedical Engineering, University of Connecticut, Mansfield, CT, United States
| | - Tiantian Guo
- Department of Biomedical Engineering, University of Connecticut, Mansfield, CT, United States
| | - Shaowei Jiang
- Department of Biomedical Engineering, University of Connecticut, Mansfield, CT, United States
| | - Longtu Chen
- Department of Biomedical Engineering, University of Connecticut, Mansfield, CT, United States
| | - Jia Liu
- Department of Biomedical Engineering, University of Connecticut, Mansfield, CT, United States
| | - Guoan Zheng
- Department of Biomedical Engineering, University of Connecticut, Mansfield, CT, United States
| | - Bin Feng
- Department of Biomedical Engineering, University of Connecticut, Mansfield, CT, United States
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15
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Berke IM, McGrath TM, Stivers JJ, Gui C, Barcellona MN, Gayoso MG, Tang SY, Cao YQ, Gupta MC, Setton LA. Electric Field Stimulation for the Functional Assessment of Isolated Dorsal Root Ganglion Neuron Excitability. Ann Biomed Eng 2021; 49:1110-1118. [PMID: 33479787 PMCID: PMC8204591 DOI: 10.1007/s10439-021-02725-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 01/05/2021] [Indexed: 10/22/2022]
Abstract
Genetically encoded calcium indicators have proven useful for characterizing dorsal root ganglion neuron excitability in vivo. Challenges persist in achieving high spatial-temporal resolutions in vivo, however, due to deep tissue imaging and motion artifacts that may be limiting technical factors in obtaining measurements. Here we report an ex vivo imaging method, using a peripheral neuron-specific Advillin-GCaMP mouse line and electric field stimulation of dorsal root ganglion tissues, to assess the sensitivity of neurons en bloc. The described method rapidly characterizes Ca2+ activity in hundreds of dorsal root ganglion neurons (221 ± 64 per dorsal root ganglion) with minimal perturbation to the in situ soma environment. We further validate the method for use as a drug screening platform with the voltage-gated sodium channel inhibitor, tetrodotoxin. Drug treatment led to decreased evoked Ca2+ activity; half-maximal response voltage (EV50) increased from 13.4 V in untreated tissues to 21.2, 23.3, 51.5 (p < 0.05), and 60.6 V (p < 0.05) at 0.01, 0.1, 1, and 10 µM doses, respectively. This technique may help improve an understanding of neural signaling while retaining tissue structural organization and serves as a tool for the rapid ex vivo recording and assessment of neural activity.
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Affiliation(s)
- Ian M Berke
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO, 63130, USA
| | - Tom M McGrath
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO, 63130, USA
| | - J Jordan Stivers
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Chang Gui
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO, 63130, USA
| | - Marcos N Barcellona
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO, 63130, USA
| | - Matthew G Gayoso
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO, 63130, USA
| | - Simon Y Tang
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Yu-Qing Cao
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Munish C Gupta
- Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Lori A Setton
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO, 63130, USA.
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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16
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Chakrabarti S, Ai M, Henson FM, Smith ESJ. Peripheral mechanisms of arthritic pain: A proposal to leverage large animals for in vitro studies. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2020; 8:100051. [PMID: 32817908 PMCID: PMC7426561 DOI: 10.1016/j.ynpai.2020.100051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 04/14/2023]
Abstract
Pain arising from musculoskeletal disorders such as arthritis is one of the leading causes of disability. Whereas the past 20-years has seen an increase in targeted therapies for rheumatoid arthritis (RA), other arthritis conditions, especially osteoarthritis, remain poorly treated. Although modulation of central pain pathways occurs in chronic arthritis, multiple lines of evidence indicate that peripherally driven pain is important in arthritic pain. To understand the peripheral mechanisms of arthritic pain, various in vitro and in vivo models have been developed, largely in rodents. Although rodent models provide numerous advantages for studying arthritis pathogenesis and treatment, the anatomy and biomechanics of rodent joints differ considerably to those of humans. By contrast, the anatomy and biomechanics of joints in larger animals, such as dogs, show greater similarity to human joints and thus studying them can provide novel insight for arthritis research. The purpose of this article is firstly to review models of arthritis and behavioral outcomes commonly used in large animals. Secondly, we review the existing in vitro models and assays used to study arthritic pain, primarily in rodents, and discuss the potential for adopting these strategies, as well as likely limitations, in large animals. We believe that exploring peripheral mechanisms of arthritic pain in vitro in large animals has the potential to reduce the veterinary burden of arthritis in commonly afflicted species like dogs, as well as to improve translatability of pain research into the clinic.
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Affiliation(s)
- Sampurna Chakrabarti
- Department of Neuroscience, Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
- Department of Pharmacology, University of Cambridge, UK
| | - Minji Ai
- Department of Veterinary Medicine, University of Cambridge, UK
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