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Logan DR, Hall J, Bianchi L. A helping hand: roles for accessory cells in the sense of touch across species. Front Cell Neurosci 2024; 18:1367476. [PMID: 38433863 PMCID: PMC10904576 DOI: 10.3389/fncel.2024.1367476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 02/05/2024] [Indexed: 03/05/2024] Open
Abstract
During touch, mechanical forces are converted into electrochemical signals by tactile organs made of neurons, accessory cells, and their shared extracellular spaces. Accessory cells, including Merkel cells, keratinocytes, lamellar cells, and glia, play an important role in the sensation of touch. In some cases, these cells are intrinsically mechanosensitive; however, other roles include the release of chemical messengers, the chemical modification of spaces that are shared with neurons, and the tuning of neural sensitivity by direct physical contact. Despite great progress in the last decade, the precise roles of these cells in the sense of touch remains unclear. Here we review the known and hypothesized contributions of several accessory cells to touch by incorporating research from multiple organisms including C. elegans, D. melanogaster, mammals, avian models, and plants. Several broad parallels are identified including the regulation of extracellular ions and the release of neuromodulators by accessory cells, as well as the emerging potential physical contact between accessory cells and sensory neurons via tethers. Our broader perspective incorporates the importance of accessory cells to the understanding of human touch and pain, as well as to animal touch and its molecular underpinnings, which are underrepresented among the animal welfare literature. A greater understanding of touch, which must include a role for accessory cells, is also relevant to emergent technical applications including prosthetics, virtual reality, and robotics.
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Affiliation(s)
| | | | - Laura Bianchi
- Department of Physiology and Biophysics, University of Miami, Miami, FL, United States
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2
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Erbacher C, Britz S, Dinkel P, Klein T, Sauer M, Stigloher C, Üçeyler N. Interaction of human keratinocytes and nerve fiber terminals at the neuro-cutaneous unit. eLife 2024; 13:e77761. [PMID: 38225894 PMCID: PMC10791129 DOI: 10.7554/elife.77761] [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: 02/09/2022] [Accepted: 12/19/2023] [Indexed: 01/17/2024] Open
Abstract
Traditionally, peripheral sensory neurons are assumed as the exclusive transducers of external stimuli. Current research moves epidermal keratinocytes into focus as sensors and transmitters of nociceptive and non-nociceptive sensations, tightly interacting with intraepidermal nerve fibers at the neuro-cutaneous unit. In animal models, epidermal cells establish close contacts and ensheath sensory neurites. However, ultrastructural morphological and mechanistic data examining the human keratinocyte-nerve fiber interface are sparse. We investigated this exact interface in human skin applying super-resolution array tomography, expansion microscopy, and structured illumination microscopy. We show keratinocyte ensheathment of afferents and adjacent connexin 43 contacts in native skin and have applied a pipeline based on expansion microscopy to quantify these parameter in skin sections of healthy participants versus patients with small fiber neuropathy. We further derived a fully human co-culture system, visualizing ensheathment and connexin 43 plaques in vitro. Unraveling human intraepidermal nerve fiber ensheathment and potential interaction sites advances research at the neuro-cutaneous unit. These findings are crucial on the way to decipher the mechanisms of cutaneous nociception.
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Affiliation(s)
| | - Sebastian Britz
- Imaging Core Facility, Biocenter, University of WürzburgWürzburgGermany
| | - Philine Dinkel
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
| | - Thomas Klein
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of WürzburgWürzburgGermany
| | | | - Nurcan Üçeyler
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
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3
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Yun HD, Goel Y, Gupta K. Crosstalk of Mast Cells and Natural Killer Cells with Neurons in Chemotherapy-Induced Peripheral Neuropathy. Int J Mol Sci 2023; 24:12543. [PMID: 37628724 PMCID: PMC10454469 DOI: 10.3390/ijms241612543] [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: 07/11/2023] [Revised: 08/04/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023] Open
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a major comorbidity of cancer. Multiple clinical interventions have been studied to effectively treat CIPN, but the results have been disappointing, with no or little efficacy. Hence, understanding the pathophysiology of CIPN is critical to improving the quality of life and clinical outcomes of cancer patients. Although various mechanisms of CIPN have been described in neuropathic anti-cancer agents, the neuroinflammatory process involving cytotoxic/proinflammatory immune cells remains underexamined. While mast cells (MCs) and natural killer (NK) cells are the key innate immune compartments implicated in the pathogenesis of peripheral neuropathy, their role in CIPN has remained under-appreciated. Moreover, the biology of proinflammatory cytokines associated with MCs and NK cells in CIPN is particularly under-evaluated. In this review, we will focus on the interactions between MCs, NK cells, and neuronal structure and their communications via proinflammatory cytokines, including TNFα, IL-1β, and IL-6, in peripheral neuropathy in association with tumor immunology. This review will help lay the foundation to investigate MCs, NK cells, and cytokines to advance future therapeutic strategies for CIPN.
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Affiliation(s)
- Hyun Don Yun
- Hematology, Oncology, Veterans Affairs Long Beach Healthcare System, Long Beach, CA 90822, USA
- Division of Hematology, Oncology, Department of Medicine, School of Medicine, University of California, Irvine, CA 92617, USA; (Y.G.); (K.G.)
| | - Yugal Goel
- Division of Hematology, Oncology, Department of Medicine, School of Medicine, University of California, Irvine, CA 92617, USA; (Y.G.); (K.G.)
| | - Kalpna Gupta
- Division of Hematology, Oncology, Department of Medicine, School of Medicine, University of California, Irvine, CA 92617, USA; (Y.G.); (K.G.)
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4
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Towards a mechanistic understanding of axon transport and endocytic changes underlying paclitaxel-induced peripheral neuropathy. Exp Neurol 2023; 359:114258. [PMID: 36279934 DOI: 10.1016/j.expneurol.2022.114258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 10/11/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022]
Abstract
Paclitaxel is a common chemotherapeutic agent widely used to treat solid cancer. However, it frequently causes peripheral sensory neuropathy, resulting in sensory abnormalities and pain in patients receiving treatment for cancer. As one of the most widely used chemotherapeutics, many preclinical studies on paclitaxel-induced peripheral neuropathy (PIPN) have been performed. Yet, there remain no effective options for treatment or prevention. Due to paclitaxel's ability to bind to and stabilize microtubules, a change in microtubule dynamics and subsequent disruptions in axonal transport has been predicted as a major underlying cause of paclitaxel-induced toxicity. However, the systemic understanding of PIPN mechanisms is largely incomplete, and various phenotypes have not been directly attributed to microtubule-related effects. This review aims to provide an overview of the literature involving paclitaxel-induced alteration in microtubule dynamics, axonal transport, and endocytic changes. It also aims to provide insights into how the microtubule-mediated hypothesis may relate to various phenotypes reported in PIPN studies.
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5
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Xu X, Yu C, Xu L, Xu J. Emerging roles of keratinocytes in nociceptive transduction and regulation. Front Mol Neurosci 2022; 15:982202. [PMID: 36157074 PMCID: PMC9500148 DOI: 10.3389/fnmol.2022.982202] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/23/2022] [Indexed: 01/07/2023] Open
Abstract
Keratinocytes are the predominant block-building cells in the epidermis. Emerging evidence has elucidated the roles of keratinocytes in a wide range of pathophysiological processes including cutaneous nociception, pruritus, and inflammation. Intraepidermal free nerve endings are entirely enwrapped within the gutters of keratinocyte cytoplasm and form en passant synaptic-like contacts with keratinocytes. Keratinocytes can detect thermal, mechanical, and chemical stimuli through transient receptor potential ion channels and other sensory receptors. The activated keratinocytes elicit calcium influx and release ATP, which binds to P2 receptors on free nerve endings and excites sensory neurons. This process is modulated by the endogenous opioid system and endothelin. Keratinocytes also express neurotransmitter receptors of adrenaline, acetylcholine, glutamate, and γ-aminobutyric acid, which are involved in regulating the activation and migration, of keratinocytes. Furthermore, keratinocytes serve as both sources and targets of neurotrophic factors, pro-inflammatory cytokines, and neuropeptides. The autocrine and/or paracrine mechanisms of these mediators create a bidirectional feedback loop that amplifies neuroinflammation and contributes to peripheral sensitization.
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Affiliation(s)
- Xiaohan Xu
- Department of Anesthesiology, Chinese Academy of Medical Sciences & Peking Union Medical College Hospital, Beijing, China
| | - Catherine Yu
- Department of Pain Management, Anesthesiology Institute, Cleveland, OH, United States,Department of Inflammation and Immunity, Lerner Research Institute, Cleveland, OH, United States,Cleveland Clinic, Case Western Reserve University, Cleveland, OH, United States
| | - Li Xu
- Department of Anesthesiology, Chinese Academy of Medical Sciences & Peking Union Medical College Hospital, Beijing, China,*Correspondence: Li Xu,
| | - Jijun Xu
- Department of Pain Management, Anesthesiology Institute, Cleveland, OH, United States,Department of Inflammation and Immunity, Lerner Research Institute, Cleveland, OH, United States,Cleveland Clinic, Case Western Reserve University, Cleveland, OH, United States,*Correspondence: Li Xu,
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6
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Differential impact of keratinocytes and fibroblasts on nociceptor degeneration and sensitization in small fiber neuropathy. Pain 2021; 162:1262-1272. [PMID: 33196576 DOI: 10.1097/j.pain.0000000000002122] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/20/2020] [Indexed: 02/07/2023]
Abstract
ABSTRACT Peripheral denervation and pain are hallmarks of small fiber neuropathy (SFN). We investigated the contribution of skin cells on nociceptor degeneration and sensitization. We recruited 56 patients with SFN and 31 healthy controls and collected skin punch biopsies for immunohistochemical and immunocytochemical analysis of netrin-1 (NTN1) and proinflammatory and anti-inflammatory cytokine expression patterns. We further applied coculture systems with murine dorsal root ganglion (DRG) neurons for skin cell-nerve interaction studies and patch-clamp analysis. Human keratinocytes attract murine DRG neuron neurites, and the gene expression of the axon guidance cue NTN1 is higher in keratinocytes of patients with SFN than in controls. NTN1 slows and reduces murine sensory neurite outgrowth in vitro, but does not alter keratinocyte cytokine expression. In the naive state, keratinocytes of patients with SFN show a higher expression of transforming growth factor-β1 (P < 0.05), while fibroblasts display higher expression of the algesic cytokines interleukin (IL)-6 (P < 0.01) and IL-8 (P < 0.05). IL-6 incubation of murine DRG neurons leads to an increase in action potential firing rates compared with baseline (P < 0.01). Our data provide evidence for a differential effect of keratinocytes and fibroblasts on nociceptor degeneration and sensitization in SFN compared with healthy controls and further supports the concept of cutaneous nociception.
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Modified tamarind kernel polysaccharide-based matrix alters neuro-keratinocyte cross-talk and serves as a suitable scaffold for skin tissue engineering. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 121:111779. [PMID: 33579440 DOI: 10.1016/j.msec.2020.111779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 11/09/2020] [Accepted: 12/02/2020] [Indexed: 11/23/2022]
Abstract
Advanced technologies like skin tissue engineering are requisite of various disorders where artificially synthesized materials need to be used as a scaffold in vivo, which in turn can allow the formation of functional skin and epidermal layer with all biological sensory functions. In this work, we present a set of hydrogels which have been synthesized by the method utilizing radical polymerization of a natural polymer extracted from kernel of Tamarindus indica, commonly known as Tamarind Kernel Powder (TKP) modified by utilizing the monomer acrylic acid (AA) in different mole ratios. These materials are termed as TKP: AA hydrogels and characterized by Atomic Force Microscopy (AFM), surface charge, and particle size distribution using Dynamic Light Scattering measurements. These materials are biocompatible with mouse dermal fibroblasts (NIH- 3T3) and human skin keratinocytes (HaCaT), as confirmed by MTT and biocompatibility assays. These TKP: AA hydrogels do not induce unwanted ROS signaling as confirmed by mitochondrial functionality determined by DCFDA staining, Mitosox imaging, and measuring the ATP levels. We demonstrate that in the co-culture system, TKP: AA allows the establishment of proper neuro-keratinocyte contact formation, suggesting that this hydrogel can be suitable for developing skin with sensory functions. Skin corrosion analysis on SD rats confirms that TKP: AA is appropriate for in vivo applications as well. This is further confirmed by in vivo compatibility and toxicity studies, including hemocompatibility and histopathology of liver and kidney upon direct introduction of hydrogel into the body. We propose that TKP: AA (1: 5) offers a suitable surface for skin tissue engineering with sensory functions applicable in vitro, in vivo, and ex vivo. These findings may have broad biomedical and clinical importance.
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Sadler KE, Moehring F, Stucky CL. Keratinocytes contribute to normal cold and heat sensation. eLife 2020; 9:58625. [PMID: 32729832 PMCID: PMC7402674 DOI: 10.7554/elife.58625] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/29/2020] [Indexed: 12/25/2022] Open
Abstract
Keratinocytes are the most abundant cell type in the epidermis, the most superficial layer of skin. Historically, epidermal-innervating sensory neurons were thought to be the exclusive detectors and transmitters of environmental stimuli. However, recent work from our lab (Moehring et al., 2018) and others (Baumbauer et al., 2015) has demonstrated that keratinocytes are also critical for normal mechanotransduction and mechanically-evoked behavioral responses in mice. Here, we asked whether keratinocyte activity is also required for normal cold and heat sensation. Using calcium imaging, we determined that keratinocyte cold activity is conserved across mammalian species and requires the release of intracellular calcium through one or more unknown cold-sensitive proteins. Both epidermal cell optogenetic inhibition and interruption of ATP-P2X4 signaling reduced reflexive behavioral responses to cold and heat stimuli. Based on these data and our previous findings, keratinocyte purinergic signaling is a modality-conserved amplification system that is required for normal somatosensation in vivo.
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Affiliation(s)
- Katelyn E Sadler
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, United States
| | - Francie Moehring
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, United States
| | - Cheryl L Stucky
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, United States
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9
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Talagas M, Lebonvallet N, Leschiera R, Elies P, Marcorelles P, Misery L. Intra-epidermal nerve endings progress within keratinocyte cytoplasmic tunnels in normal human skin. Exp Dermatol 2020; 29:387-392. [PMID: 32003039 DOI: 10.1111/exd.14081] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/10/2019] [Accepted: 01/21/2020] [Indexed: 12/29/2022]
Abstract
Intra-epidermal nerve endings, responsible for cutaneous perception of temperature, pain and itch, are conventionally described as passing freely between keratinocytes, from the basal to the granular layers of the epidermis. However, the recent discovery of keratinocyte contribution to cutaneous nociception implies that their anatomical relationships are much more intimate than what has been described so far. By studying human skin biopsies in confocal laser scanning microscopy, we show that intra-epidermal nerve endings are not only closely apposed to keratinocytes, but can also be enwrapped by keratinocyte cytoplasms over their entire circumference and thus progress within keratinocyte tunnels. As keratinocytes must activate intra-epidermal nerve endings to transduce nociceptive information, these findings may help understanding the interactions between the keratinocytes and nervous system. The discovery of these nerve portions progressing in keratinocyte tunnels is a strong argument to consider that contacts between epidermal keratinocytes and intra-epidermal nerve endings are not incidental and argue for the existence of specific and rapid paracrine communication from keratinocytes to sensory neurons.
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Affiliation(s)
- Matthieu Talagas
- Univ Brest, LIEN, Brest, France
- Department of Pathology, Brest University Hospital, Brest, France
| | | | | | - Philippe Elies
- Univ Brest, Imagery and Microscopic Measures Facility, Brest, France
| | - Pascale Marcorelles
- Univ Brest, LIEN, Brest, France
- Department of Pathology, Brest University Hospital, Brest, France
| | - Laurent Misery
- Univ Brest, LIEN, Brest, France
- Department of Dermatology, Brest University Hospital, Brest, France
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10
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Jonas R, Prato V, Lechner SG, Groen G, Obreja O, Werland F, Rukwied R, Klusch A, Petersen M, Carr RW, Schmelz M. TTX-Resistant Sodium Channels Functionally Separate Silent From Polymodal C-nociceptors. Front Cell Neurosci 2020; 14:13. [PMID: 32116559 PMCID: PMC7018684 DOI: 10.3389/fncel.2020.00013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/17/2020] [Indexed: 01/09/2023] Open
Abstract
Pronounced activity-dependent slowing of conduction has been used to characterize mechano-insensitive, “silent” nociceptors and might be due to high expression of NaV1.8 and could, therefore, be characterized by their tetrodotoxin-resistance (TTX-r). Nociceptor-class specific differences in action potential characteristics were studied by: (i) in vitro calcium imaging in single porcine nerve growth factor (NGF)-responsive neurites; (ii) in vivo extracellular recordings in functionally identified porcine silent nociceptors; and (iii) in vitro patch-clamp recordings from murine silent nociceptors, genetically defined by nicotinic acetylcholine receptor subunit alpha-3 (CHRNA3) expression. Porcine TTX-r neurites (n = 26) in vitro had more than twice as high calcium transients per action potential as compared to TTX-s neurites (n = 18). In pig skin, silent nociceptors (n = 14) characterized by pronounced activity-dependent slowing of conduction were found to be TTX-r, whereas polymodal nociceptors were TTX-s (n = 12) and had only moderate slowing. Mechano-insensitive cold nociceptors were also TTX-r but showed less activity-dependent slowing than polymodal nociceptors. Action potentials in murine silent nociceptors differed from putative polymodal nociceptors by longer duration and higher peak amplitudes. Longer duration AP in silent murine nociceptors linked to increased sodium load would be compatible with a pronounced activity-dependent slowing in pig silent nociceptors and longer AP durations could be in line with increased calcium transients per action potential observed in vitro in TTX-resistant NGF responsive porcine neurites. Even though there is no direct link between slowing and TTX-resistant channels, the results indicate that axons of silent nociceptors not only differ in their receptive but also in their axonal properties.
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Affiliation(s)
- Robin Jonas
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Vincenzo Prato
- Institute of Pharmacology, University of Heidelberg, Heidelberg, Germany
| | - Stefan G Lechner
- Institute of Pharmacology, University of Heidelberg, Heidelberg, Germany
| | - Gerbrand Groen
- Department of Anesthesiology, Groningen University, Groningen, Netherlands
| | - Otilia Obreja
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Fiona Werland
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Roman Rukwied
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Andreas Klusch
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Marlen Petersen
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Richard W Carr
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Martin Schmelz
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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11
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Moehring F, Halder P, Seal RP, Stucky CL. Uncovering the Cells and Circuits of Touch in Normal and Pathological Settings. Neuron 2019; 100:349-360. [PMID: 30359601 DOI: 10.1016/j.neuron.2018.10.019] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 01/18/2023]
Abstract
The sense of touch is fundamental as it provides vital, moment-to-moment information about the nature of our physical environment. Primary sensory neurons provide the basis for this sensation in the periphery; however, recent work demonstrates that touch transduction mechanisms also occur upstream of the sensory neurons via non-neuronal cells such as Merkel cells and keratinocytes. Within the spinal cord, deep dorsal horn circuits transmit innocuous touch centrally and also transform touch into pain in the setting of injury. Here non-neuronal cells play a key role in the induction and maintenance of persistent mechanical pain. This review highlights recent advances in our understanding of mechanosensation, including a growing appreciation for the role of non-neuronal cells in both touch and pain.
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Affiliation(s)
- Francie Moehring
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Priyabrata Halder
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Center for the Neural Basis of Cognition, Pittsburgh, PA 15213, USA
| | - Rebecca P Seal
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Center for the Neural Basis of Cognition, Pittsburgh, PA 15213, USA; Pittsburgh Center for Pain Research, Pittsburgh, PA 15213, USA
| | - Cheryl L Stucky
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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12
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Klusch A, Gorzelanny C, Reeh PW, Schmelz M, Petersen M, Sauer SK. Local NGF and GDNF levels modulate morphology and function of porcine DRG neurites, In Vitro. PLoS One 2018; 13:e0203215. [PMID: 30260982 PMCID: PMC6160011 DOI: 10.1371/journal.pone.0203215] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/16/2018] [Indexed: 11/26/2022] Open
Abstract
Nerve terminals of primary sensory neurons are influenced by their environment through target derived trophic factors, like nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF). In mice, subpopulations of DRG neurons express receptors either for NGF or GDNF and therefore differentially respond to these neurotrophic factors. We probed neurite endings from porcine DRG neurons cultured in either NGF or GDNF and examined their shape, elongation and stimulus-evoked CGRP release. A compartmentalized culture system was employed allowing spatial separation of outgrown neurites from their somata and use of different growth factors in the compartments. We show that neurites of GDNF cultured somata extend into lateral compartments without added growth factor, unlike neurites of NGF cultured ones. Neurites of NGF cultured somata extend not only into NGF- but also into GDNF-containing compartments. GDNF at the site of terminals of NGF responsive somata led to a strong neurite arborization and formation of large growth cones, compared to neurites in medium with NGF. Functionally, we could detect evoked CGRP release from as few as 7 outgrown neurites per compartment and calculated release per mm neurite length. CGRP release was detected both in neurites from NGF and GDNF cultured somata, suggesting that also the latter ones are peptidergic in pig. When neurites of NGF cultured somata were grown in GDNF, capsaicin evoked a lower CGRP release than high potassium, compared to those grown in NGF. Our experiments demonstrate that the compartmented culture chamber can be a suitable model to assess neurite properties from trophic factor specific primary sensory neurons. With this model, insights into mechanisms of gain or loss of function of specific nociceptive neurites may be achieved.
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Affiliation(s)
- Andreas Klusch
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Christian Gorzelanny
- Department of Dermatology and Venereology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Peter W. Reeh
- Institute of Physiology and Pathophysiology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Martin Schmelz
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Marlen Petersen
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Susanne K. Sauer
- Institute of Physiology and Pathophysiology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
- * E-mail:
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13
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Tillmaand EG, Sweedler JV. Integrating Mass Spectrometry with Microphysiological Systems for Improved Neurochemical Studies. ACTA ACUST UNITED AC 2018; 2. [PMID: 30148282 DOI: 10.21037/mps.2018.05.01] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Microphysiological systems, often referred to as "organs-on-chips", are in vitro platforms designed to model the spatial, chemical, structural, and physiological elements of in vivo cellular environments. They enhance the evaluation of complex engineered biological systems and are a step between traditional cell culture and in vivo experimentation. As neurochemists and measurement scientists studying the molecules involved in intercellular communication in the nervous system, we focus here on recent advances in neuroscience using microneurological systems and their potential to interface with mass spectrometry. We discuss a number of examples - microfluidic devices, spheroid cultures, hydrogels, scaffolds, and fibers - highlighting those that would benefit from mass spectrometric technologies to obtain improved chemical information.
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Affiliation(s)
- Emily G Tillmaand
- Department of Chemistry, the Neuroscience Program and the Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jonathan V Sweedler
- Department of Chemistry, the Neuroscience Program and the Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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14
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Moehring F, Cowie AM, Menzel AD, Weyer AD, Grzybowski M, Arzua T, Geurts AM, Palygin O, Stucky CL. Keratinocytes mediate innocuous and noxious touch via ATP-P2X4 signaling. eLife 2018; 7:31684. [PMID: 29336303 PMCID: PMC5777822 DOI: 10.7554/elife.31684] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/29/2017] [Indexed: 12/22/2022] Open
Abstract
The first point of our body’s contact with tactile stimuli (innocuous and noxious) is the epidermis, the outermost layer of skin that is largely composed of keratinocytes. Here, we sought to define the role that keratinocytes play in touch sensation in vivo and ex vivo. We show that optogenetic inhibition of keratinocytes decreases behavioral and cellular mechanosensitivity. These processes are inherently mediated by ATP signaling, as demonstrated by complementary cutaneous ATP release and degradation experiments. Specific deletion of P2X4 receptors in sensory neurons markedly decreases behavioral and primary afferent mechanical sensitivity, thus positioning keratinocyte-released ATP to sensory neuron P2X4 signaling as a critical component of baseline mammalian tactile sensation. These experiments lay a vital foundation for subsequent studies into the dysfunctional signaling that occurs in cutaneous pain and itch disorders, and ultimately, the development of novel topical therapeutics for these conditions. The skin is the largest sensory organ of the body, and the first point of contact with the outside world. Whether it is being pinched or caressed, the skin’s sense of touch informs organisms about their surroundings and allows them to react appropriately. Nerve cells present in the skin capture information about touch and transmit it to the brain where it is decoded. However, there are many other types of cells in the skin besides nerve cells. The role that these other skin cells play in perceiving non-painful and painful touch is still unclear. Moehring et al. now report how the skin cells that form 95% of the most outer layer of the skin are involved in detecting touch. In mutant mice whose cells can be ‘switched off’ by a certain light, artificially deactivating these cells makes the animals less able to respond to tactile stimuli. Further experiments show that when pressure is applied onto the skin, the surface skin cells release a chemical messenger, which then binds specifically to the nerve cells. When the messaging molecule is experimentally destroyed or prevented from attaching to the nerve cell, the mice react less to non-painful and painful touch. This means the cells at the surface of the skin detect tactile signals from the environment and then communicate this information to the nerve cells, where it is taken to the brain. Disrupted communication between the cells in the outer layer of the skin and the nerve cells is found in painful and itchy skin conditions such as eczema and psoriasis. Knowing how these two types of cells normally work together may help with finding new pain and itch treatments for these skin disorders.
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Affiliation(s)
- Francie Moehring
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, United States
| | - Ashley M Cowie
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, United States
| | - Anthony D Menzel
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, United States
| | - Andy D Weyer
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, United States
| | - Michael Grzybowski
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States
| | - Thiago Arzua
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States
| | - Aron M Geurts
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States
| | - Cheryl L Stucky
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, United States
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15
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Talagas M, Lebonvallet N, Leschiera R, Marcorelles P, Misery L. What about physical contacts between epidermal keratinocytes and sensory neurons? Exp Dermatol 2017; 27:9-13. [DOI: 10.1111/exd.13411] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2017] [Indexed: 01/01/2023]
Affiliation(s)
- Matthieu Talagas
- Laboratory of Interactions Neurons Keratinocytes (EA4685); Faculty of Medicine and Health Sciences; University of Western Brittany; Brest France
- Department of Pathology; Brest University Hospital; Brest France
- IBSAM (Institut Brestois de Santé Agro Matière); University of Western Brittany; Brest France
| | - Nicolas Lebonvallet
- Laboratory of Interactions Neurons Keratinocytes (EA4685); Faculty of Medicine and Health Sciences; University of Western Brittany; Brest France
- IBSAM (Institut Brestois de Santé Agro Matière); University of Western Brittany; Brest France
| | - Raphael Leschiera
- Laboratory of Interactions Neurons Keratinocytes (EA4685); Faculty of Medicine and Health Sciences; University of Western Brittany; Brest France
- IBSAM (Institut Brestois de Santé Agro Matière); University of Western Brittany; Brest France
| | - Pascale Marcorelles
- Laboratory of Interactions Neurons Keratinocytes (EA4685); Faculty of Medicine and Health Sciences; University of Western Brittany; Brest France
- Department of Pathology; Brest University Hospital; Brest France
- IBSAM (Institut Brestois de Santé Agro Matière); University of Western Brittany; Brest France
| | - Laurent Misery
- Laboratory of Interactions Neurons Keratinocytes (EA4685); Faculty of Medicine and Health Sciences; University of Western Brittany; Brest France
- IBSAM (Institut Brestois de Santé Agro Matière); University of Western Brittany; Brest France
- Department of Dermatology; Brest University Hospital; Brest France
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16
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Krishnan-Kutty V, Bigliardi PL, Dykas MM, Pomp O, Kyaw HM, Poddar K, Venkatesan T, Bigliardi-Qi M. Peripheral nerve fibres form multifacet interactions with keratinocytes in a novel complete human 2D culture model. Exp Dermatol 2017; 26:281-284. [DOI: 10.1111/exd.13181] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2016] [Indexed: 12/29/2022]
Affiliation(s)
| | - Paul L. Bigliardi
- Institute of Medical Biology; A-STAR; Singapore Singapore
- YLL School of Medicine; National University of Singapore (NUS); Singapore Singapore
- National University Health System (NUHS); Singapore Singapore
| | - Michal Marcin Dykas
- NUS Nanoscience and Nanotechnology Institute (NUSNNI); Singapore Singapore
- NUS Graduate School for Integrative Sciences and Engineering; National University of Singapore Singapore
| | - Oz Pomp
- Institute of Medical Biology; A-STAR; Singapore Singapore
| | | | - Kingshuk Poddar
- NUS Nanoscience and Nanotechnology Institute (NUSNNI); Singapore Singapore
- NUS Graduate School for Integrative Sciences and Engineering; National University of Singapore Singapore
| | - T. Venkatesan
- NUS Nanoscience and Nanotechnology Institute (NUSNNI); Singapore Singapore
- NUS Graduate School for Integrative Sciences and Engineering; National University of Singapore Singapore
- Singapore Synchrotron Light Source; National University of Singapore Singapore
- Department of Electrical and Computer Engineering; National University of Singapore Singapore
- Department of Physics; National University of Singapore Singapore. Department of Materials Science and Engineering; National University of Singapore Singapore
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17
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Identification of an epidermal keratinocyte AMPA glutamate receptor involved in dermatopathies associated with sensory abnormalities. Pain Rep 2016; 1. [PMID: 28210712 PMCID: PMC5305184 DOI: 10.1097/pr9.0000000000000573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Supplemental Digital Content is Available in the Text. This study presents the discovery of AMPA glutamate receptors in mouse and human epidermal keratinocytes and their potential role in the physiopathology of itch or pain. Introduction: Epidermal keratinocytes are increasingly recognized as active participants in the sensory transduction of itch and pain, processes known to involve primary afferent glutamatergic neurons. However, the role of keratinocyte glutamate signaling in sensory functioning is not fully understood. Here, we present the observation of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid–type glutamate receptors (AMPARs) in epidermal keratinocytes. Methods: Immunohistochemical and in situ hybridization analyses were conducted to assess the expression of AMPAR subunits in epidermal keratinocytes in mouse and human skin samples, and in organotypic cultures of human keratinocytes. In addition, reverse transcription PCR further confirmed the expression of GluA4-containing AMPAR in epidermal keratinocytes. Results: We found prominent immunolabeling for the GluA4 subunit of AMPAR in keratinocytes of glabrous and hairy skin of mouse epidermis, as well as in human epidermal keratinocytes. Reverse transcription PCR confirmed Gria4 transcript expression in epidermal mouse keratinocytes. In addition, expression of GRIA4 mRNA was confirmed in epidermal human keratinocytes by in situ hybridization. Immunohistochemical studies conducted in human skin biopsies from patients with atopic dermatitis and postherpetic neuralgia demonstrate that keratinocyte expression of GluA4 can be altered under pathological conditions. Moreover, a decrease of GluA4 expression was observed in organotypic cultures of human keratinocytes after direct application of algogenic agents. Conclusion: We provide evidence that GluA4-containing AMPARs are expressed in epidermal keratinocytes, that human pruritic and painful dermatopathologies have alterations in the keratinocyte expression levels of GluA4-containing AMPAR, and that itch- and pain-producing substances can directly regulate their production in keratinocytes.
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Zappia KJ, Garrison SR, Palygin O, Weyer AD, Barabas ME, Lawlor MW, Staruschenko A, Stucky CL. Mechanosensory and ATP Release Deficits following Keratin14-Cre-Mediated TRPA1 Deletion Despite Absence of TRPA1 in Murine Keratinocytes. PLoS One 2016; 11:e0151602. [PMID: 26978657 PMCID: PMC4792390 DOI: 10.1371/journal.pone.0151602] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/01/2016] [Indexed: 12/20/2022] Open
Abstract
Keratinocytes are the first cells that come into direct contact with external tactile stimuli; however, their role in touch transduction in vivo is not clear. The ion channel Transient Receptor Potential Ankyrin 1 (TRPA1) is essential for some mechanically-gated currents in sensory neurons, amplifies mechanical responses after inflammation, and has been reported to be expressed in human and mouse skin. Other reports have not detected Trpa1 mRNA transcripts in human or mouse epidermis. Therefore, we set out to determine whether selective deletion of Trpa1 from keratinocytes would impact mechanosensation. We generated K14Cre-Trpa1fl/fl mice lacking TRPA1 in K14-expressing cells, including keratinocytes. Surprisingly, Trpa1 transcripts were very poorly detected in epidermis of these mice or in controls, and detection was minimal enough to preclude observation of Trpa1 mRNA knockdown in the K14Cre-Trpa1fl/fl mice. Unexpectedly, these K14Cre-Trpa1fl/fl mice nonetheless exhibited a pronounced deficit in mechanosensitivity at the behavioral and primary afferent levels, and decreased mechanically-evoked ATP release from skin. Overall, while these data suggest that the intended targeted deletion of Trpa1 from keratin 14-expressing cells of the epidermis induces functional deficits in mechanotransduction and ATP release, these deficits are in fact likely due to factors other than reduction of Trpa1 expression in adult mouse keratinocytes because they express very little, if any, Trpa1.
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Affiliation(s)
- Katherine J. Zappia
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Sheldon R. Garrison
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Andy D. Weyer
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Marie E. Barabas
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Michael W. Lawlor
- Division of Pediatric Pathology, Department of Pathology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Cheryl L. Stucky
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
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19
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Abstract
The skin epidermis is densely innervated by peripheral sensory nerve endings. Nociceptive neurons, whose terminals are in close contact with epidermal keratinocytes, can be activated directly by noxious physical and chemical stimuli to trigger pain. However, whether keratinocytes can signal acutely to sensory nerve terminals to initiate pain in vivo remains unclear. Here, using the keratin 5 promoter to selectively express the capsaicin receptor TRPV1 in keratinocytes of TRPV1-knockout mice, we achieved specific stimulation of keratinocytes with capsaicin. Using this approach, we found that keratinocyte stimulation was sufficient to induce strong expression of the neuronal activation marker, c-fos, in laminae I and II of the ipsilateral spinal cord dorsal horn and to evoke acute paw-licking nocifensive behavior and conditioned place aversion. These data provide direct evidence that keratinocyte stimulation is sufficient to evoke acute nociception-related responses.
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20
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Assessment of TTX-s and TTX-r Action Potential Conduction along Neurites of NGF and GDNF Cultured Porcine DRG Somata. PLoS One 2015; 10:e0139107. [PMID: 26407014 PMCID: PMC4583387 DOI: 10.1371/journal.pone.0139107] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/09/2015] [Indexed: 12/19/2022] Open
Abstract
Nine isoforms of voltage-gated sodium channels (NaV) have been characterized and in excitable tissues they are responsible for the initiation and conduction of action potentials. For primary afferent neurons residing in dorsal root ganglia (DRG), individual neurons may express multiple NaV isoforms extending the neuron’s functional capabilities. Since expression of NaV isoforms can be differentially regulated by neurotrophic factors we have examined the functional consequences of exposure to either nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF) on action potential conduction in outgrowing cultured porcine neurites of DRG neurons. Calcium signals were recorded using the exogenous intensity based calcium indicator Fluo-8®, AM. In 94 neurons, calcium signals were conducted along neurites in response to electrical stimulation of the soma. At an image acquisition rate of 25 Hz it was possible to discern calcium transients in response to individual electrical stimuli. The peak amplitude of electrically-evoked calcium signals was limited by the ability of the neuron to follow the stimulus frequency. The stimulus frequency required to evoke a half-maximal calcium response was approximately 3 Hz at room temperature. In 13 of 14 (93%) NGF-responsive neurites, TTX-r NaV isoforms alone were sufficient to support propagated signals. In contrast, calcium signals mediated by TTX-r NaVs were evident in only 4 of 11 (36%) neurites from somata cultured in GDNF. This establishes a basis for assessing action potential signaling using calcium imaging techniques in individual cultured neurites and suggests that, in the pig, afferent nociceptor classes relying on the functional properties of TTX-r NaV isoforms, such as cold-nociceptors, most probably derive from NGF-responsive DRG neurons.
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