scholarly journals A ligand-receptor interactome platform for discovery of pain mechanisms and therapeutic targets

2021 ◽  
Vol 14 (674) ◽  
pp. eabe1648
Author(s):  
Andi Wangzhou ◽  
Candler Paige ◽  
Sanjay V. Neerukonda ◽  
Dhananjay K. Naik ◽  
Moeno Kume ◽  
...  

In the peripheral nervous system, ligand-receptor interactions between cells and neurons shape sensory experience, including pain. We set out to identify the potential interactions between sensory neurons and peripheral cell types implicated in disease-associated pain. Using mouse and human RNA sequencing datasets and computational analysis, we created interactome maps between dorsal root ganglion (DRG) sensory neurons and an array of normal cell types, as well as colitis-associated glial cells, rheumatoid arthritis–associated synovial macrophages, and pancreatic tumor tissue. These maps revealed a common correlation between the abundance of heparin-binding EGF-like growth factor (HBEGF) in peripheral cells with that of its receptor EGFR (a member of the ErbB family of receptors) in DRG neurons. Subsequently, we confirmed that increased abundance of HBEGF enhanced nociception in mice, likely acting on DRG neurons through ErbB family receptors. Collectively, these interactomes highlight ligand-receptor interactions that may lead to treatments for disease-associated pain and, furthermore, reflect the complexity of cell-to-neuron signaling in chronic pain states.

Author(s):  
Andi Wangzhou ◽  
Candler Paige ◽  
Sanjay V Neerukonda ◽  
Gregory Dussor ◽  
Pradipta R Ray ◽  
...  

AbstractCells communicate with each other through ligand and receptor interactions. In the case of the peripheral nervous system, these ligand-receptor interactions shape sensory experience. In disease states, such as chronic pain, these ligand-receptor interactions can change the excitability of target neurons augmenting nociceptive input to the CNS. While the importance of these cell to neuron interactions are widely acknowledged, they have not been thoroughly characterized. We sought to address this by cataloging how peripheral cell types interact with sensory neurons in the dorsal root ganglion (DRG) using RNA sequencing datasets. Using single cell sequencing datasets from mouse we created a comprehensive interactome map for how mammalian sensory neurons interact with 42 peripheral cell types. We used this knowledge base to understand how specific cell types and sensory neurons interact in disease states. In mouse datasets, we created an interactome of colonic enteric glial cells in the naïve and inflamed state with sensory neurons that specifically innervate this tissue. In human datasets, we created interactomes of knee joint macrophages from rheumatoid arthritis patients and pancreatic cancer samples with human DRG. Collectively, these interactomes highlight ligand-receptor interactions in mouse models and human disease states that reflect the complexity of cell to neuron signaling in chronic pain states. These interactomes also highlight therapeutic targets, such as the epidermal growth factor receptor (EGFR), which was a common interaction point emerging from our studies.


Author(s):  
Diana Tavares-Ferreira ◽  
Stephanie Shiers ◽  
Pradipta R. Ray ◽  
Andi Wangzhou ◽  
Vivekanand Jeevakumar ◽  
...  

AbstractSingle-cell transcriptomics on mouse nociceptors has transformed our understanding of pain mechanisms. Equivalent information from human nociceptors is lacking. We used spatial transcriptomics to molecularly characterize transcriptomes of single dorsal root ganglion (DRG) neurons from 8 organ donors. We identified 10 clusters of human sensory neurons, 6 of which are C nociceptors, 1 Aβ nociceptor, 1 Aδ, and 2 Aβ subtypes. These neuron subtypes have distinct expression profiles from rodents and non-human primates and we identify new markers for each of these subtypes that can be applied broadly in human studies. We also identify sex differences, including a marked increase in CALCA expression in female putative itch nociceptors. Our data open the door to new pain targets and unparalleled molecular characterization of clinical sensory disorders.One Sentence SummaryThree A-fiber mechanoreceptor and seven nociceptor subtypes are identified, revealing sex differences and unique aspects of human DRG neurons.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Lei He ◽  
Quan Zhang ◽  
Yue Zhang ◽  
Yixian Fan ◽  
Fahu Yuan ◽  
...  

Abstract Background The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) has become an ongoing pandemic. Understanding the respiratory immune microenvironment which is composed of multiple cell types, together with cell communication based on ligand–receptor interactions is important for developing vaccines, probing COVID-19 pathogenesis, and improving pandemic control measures. Methods A total of 102 consecutive hospitalized patients with confirmed COVID-19 were enrolled in this study. Clinical information, routine laboratory tests, and flow cytometry analysis data with different conditions were collected and assessed for predictive value in COVID-19 patients. Next, we analyzed public single-cell RNA-sequencing (scRNA-seq) data from bronchoalveolar lavage fluid, which offers the closest available view of immune cell heterogeneity as encountered in patients with varying severity of COVID-19. A weighting algorithm was used to calculate ligand–receptor interactions, revealing the communication potentially associated with outcomes across cell types. Finally, serum cytokines including IL6, IL1β, IL10, CXCL10, TNFα, GALECTIN-1, and IGF1 derived from patients were measured. Results Of the 102 COVID-19 patients, 42 cases (41.2%) were categorized as severe. Multivariate logistic regression analysis demonstrated that AST, D-dimer, BUN, and WBC were considered as independent risk factors for the severity of COVID-19. T cell numbers including total T cells, CD4+ and CD8+ T cells in the severe disease group were significantly lower than those in the moderate disease group. The risk model containing the above mentioned inflammatory damage parameters, and the counts of T cells, with AUROCs ranged from 0.78 to 0.87. To investigate the molecular mechanism at the cellular level, we analyzed the published scRNA-seq data and found that macrophages displayed specific functional diversity after SARS-Cov-2 infection, and the metabolic pathway activities in the identified macrophage subtypes were influenced by hypoxia status. Importantly, we described ligand–receptor interactions that are related to COVID-19 serverity involving macrophages and T cell subsets by communication analysis. Conclusions Our study showed that macrophages driving ligand–receptor crosstalk contributed to the reduction and exhaustion of CD8+ T cells. The identified crucial cytokine panel, including IL6, IL1β, IL10, CXCL10, IGF1, and GALECTIN-1, may offer the selective targets to improve the efficacy of COVID-19 therapy. Trial registration: This is a retrospective observational study without a trial registration number.


2004 ◽  
Vol 18 (8) ◽  
pp. 2035-2048 ◽  
Author(s):  
Bukhtiar H. Shah ◽  
Akin Yesilkaya ◽  
J. Alberto Olivares-Reyes ◽  
Hung-Dar Chen ◽  
László Hunyady ◽  
...  

1994 ◽  
Vol 107 (2) ◽  
pp. 401-411
Author(s):  
N. Flint ◽  
F.L. Cove ◽  
G.S. Evans

Heparin is a sulphated glycosaminoglycan derived from mast cells and has a number of functions including the inhibition of proliferation in several cell types and interactions with a range of heparin-binding growth factors. We report that heparin is a trophic factor in primary cultures of rat small intestinal epithelium. Heparin elicits a dose-dependent increase in epithelial proliferation and inhibits the growth of associated mesenchyme. The trophic effect of this molecule is not reproduced by other glycosaminoglycans including heparan sulphate but is dependent upon extensive molecular sulphation. Highly sulphated polysaccharides that are structurally unrelated to heparin (e.g. dextran sulphate and pentosan polysulphate) also stimulate epithelial proliferation in primary cultures. Heparin may act by the potentiation of mesenchyme-derived heparin-binding growth factors and these data suggest an in vivo role for mast cell-derived heparin in mucosal wound regeneration.


Author(s):  
Edward C. Emery ◽  
Patrik Ernfors

Primary sensory neurons of the dorsal root ganglion (DRG) respond and relay sensations that are felt, such as those for touch, pain, temperature, itch, and more. The ability to discriminate between the various types of stimuli is reflected by the existence of specialized DRG neurons tuned to respond to specific stimuli. Because of this, a comprehensive classification of DRG neurons is critical for determining exactly how somatosensation works and for providing insights into cell types involved during chronic pain. This article reviews the recent advances in unbiased classification of molecular types of DRG neurons in the perspective of known functions as well as predicted functions based on gene expression profiles. The data show that sensory neurons are organized in a basal structure of three cold-sensitive neuron types, five mechano-heat sensitive nociceptor types, four A-Low threshold mechanoreceptor types, five itch-mechano-heat–sensitive nociceptor types and a single C–low-threshold mechanoreceptor type with a strong relation between molecular neuron types and functional types. As a general feature, each neuron type displays a unique and predicable response profile; at the same time, most neuron types convey multiple modalities and intensities. Therefore, sensation is likely determined by the summation of ensembles of active primary afferent types. The new classification scheme will be instructive in determining the exact cellular and molecular mechanisms underlying somatosensation, facilitating the development of rational strategies to identify causes for chronic pain.


Author(s):  
Kentaro Nishida ◽  
Yuka Nomura ◽  
Kanako Kawamori ◽  
Akihiro Ohishi ◽  
Kazuki Nagasawa

In dorsal root ganglion (DRG) neurons, ATP is an important neurotransmitter in nociceptive signaling through P2 receptors (P2Rs) such as P2X2/3R, and adenosine is also involved in anti-nociceptive signaling through adenosine A1R. Thus, the clearance system for adenine nucleotide/nucleoside plays a critical role in regulation of nociceptive signaling, but there is little information on it, especially ectoenzyme expression profiles in DRG. In this study, we examined expression and localization of ecto-nucleotide pyrophosphatase/phosphodiesterases (ENPPs), by which ATP is metabolized to AMP, in rat DRG. The mRNA expression levels of ENPP2 were greater than those of ENPP1 and ENPP3 in rat DRGs. On immunohistochemical analysis, ENPP1, 2 and 3 were found in soma of DRG neurons. Immunopositive rate of ENPP3 was greater than that of ENPP1 and ENPP2 in all DRG neurons. ENPP3, as compared with ENPP1 and ENPP2, was expressed mainly by isolectin B4-positive cells, and slightly by neurofilament 200-positive ones. In this way, the expression profile of ENPP1, 2 and 3 was different in DRGs, and they were mainly expressed in small/medium-sized DRG neurons. Moreover, ENPP1-, 2- and 3-immunoreactivities were colocalized with P2X2R, P2X3R and prostatic acid phosphatase (PAP), as an ectoenzyme for metabolism from AMP to adenosine. Additionally, PAP-immunoreactivity was colocalized with equilibrative nucleoside transporter (ENT) 1, as an adenosine uptake system. These results suggest that the clearance system consisted of ENPPs, PAP and ENT1 plays an important role in regulation of nociceptive signaling in sensory neurons.


2019 ◽  
Vol 116 (12) ◽  
pp. 5514-5522 ◽  
Author(s):  
Elan Z. Eisenmesser ◽  
Adrian Gottschlich ◽  
Jasmina S. Redzic ◽  
Natasia Paukovich ◽  
Jay C. Nix ◽  
...  

Interleukin-37 (IL-37), a member of the IL-1 family of cytokines, is a fundamental suppressor of innate and acquired immunities. Here, we used an integrative approach that combines biophysical, biochemical, and biological studies to elucidate the unique characteristics of IL-37. Our studies reveal that single amino acid mutations at the IL-37 dimer interface that result in the stable formation of IL-37 monomers also remain monomeric at high micromolar concentrations and that these monomeric IL-37 forms comprise higher antiinflammatory activities than native IL-37 on multiple cell types. We find that, because native IL-37 forms dimers with nanomolar affinity, higher IL-37 only weakly suppresses downstream markers of inflammation whereas lower concentrations are more effective. We further show that IL-37 is a heparin binding protein that modulates this self-association and that the IL-37 dimers must block the activity of the IL-37 monomer. Specifically, native IL-37 at 2.5 nM reduces lipopolysaccharide (LPS)-induced vascular cell adhesion molecule (VCAM) protein levels by ∼50%, whereas the monomeric D73K mutant reduced VCAM by 90% at the same concentration. Compared with other members of the IL-1 family, both the N and the C termini of IL-37 are extended, and we show they are disordered in the context of the free protein. Furthermore, the presence of, at least, one of these extended termini is required for IL-37 suppressive activity. Based on these structural and biological studies, we present a model of IL-37 interactions that accounts for its mechanism in suppressing innate inflammation.


2014 ◽  
Vol 5;17 (5;9) ◽  
pp. E609-E618
Author(s):  
Nebojsa N. Knezevic

Background: Epidural and intrathecal injections of methylprednisolone acetate (MPA) have become the most commonly performed interventional procedures in the United States and worldwide in the last 2 decades. However neuraxial MPA injection has been dogged by controversy regarding the presence of different additives used in commercially prepared glucocorticoids. We previously showed that MPA could be rendered 85% free of polyethylene glycol (PEG) by a simple physical separation of elements in the suspension. Objective: The objective of the present study was to explore a possible cytotoxic effect of commercially available MPA (with intact or reduced preservatives) on rat sensory neurons. Methods: We exposed primary dissociated rat dorsal root ganglia (DRG) sensory neurons to commercially available MPA for 24 hours with either the standard (commercial) concentration of preservatives or to different fractions following separation (MPA suspension whose preservative concentration had been reduced, or fractions containing higher concentrations of preservatives). Cells were stained with the TUNEL assay kit to detect apoptotic cells and images were taken on the Bio-Rad Laser Sharp-2000 system. We also detected expression of caspase-3, as an indicator of apoptosis in cell lysates. Results: We exposed sensory neurons from rat DRG to different concentrations of MPA from the original commercially prepared vial. TUNEL assay showed dose-related responses and increased percentages of apoptotic cells with increasing concentrations of MPA. Increased concentrations of MPA caused 1.5 – 2 times higher caspase-3 expression in DRG sensory neurons than in control cells (ANOVA, P = 0.001). Our results showed that MPA with reduced preservatives caused significantly less apoptosis observed with TUNEL assay labeling (P < 0.001) and caspase-3 immunoblotting (P ≤ 0.001) than in neurons exposed to MPA from a commercially prepared vial or “clear phase” that contained higher concentrations of preservatives. Even though MPA with reduced preservatives caused 12.5% more apoptosis in DRG sensory neurons than in control cells, post hoc analysis showed no differences between these 2 groups. Limitations: Our data was collected from in vitro isolated rat DRG neurons. There is a possibility that in vivo neurons have different extents of vulnerability compared to isolated neurons. Conclusions: Results of the present study identified a cytotoxic effect of commercially available MPA with preservatives or with a “clear phase” containing higher concentrations of preservatives on primary isolated rat DRG sensory neurons. This was shown by TUNEL positive assay and by increased caspase-3 expression as one of the final executing steps in apoptotic pathways in DRG neurons. However, our results showed no statistically significant difference between the control cells (salinetreated) and cells treated with MPA with reduced concentrations of preservatives, pointing out that either PEG or myristylgamma-picolinium chloride (MGPC) or their combination have harmful effects on these cells. Reduction of concentrations of preservatives from commercially available MPA suspensions by using the simple method of inverting vials for 2 hours could be considered useful in clinical practice to enhance the safety of this depot steroid when injected neuraxially. Key words: Methylprednisolone acetate, preservatives, dorsal root ganglion sensory neurons, cytotoxic effect, polyethylene glycol, myristylgamma-picolinium chloride


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Xiulin Zhang ◽  
Birgit T Priest ◽  
Inna Belfer ◽  
Michael S Gold

Available evidence indicates voltage-gated Na+ channels (VGSCs) in peripheral sensory neurons are essential for the pain and hypersensitivity associated with tissue injury. However, our understanding of the biophysical and pharmacological properties of the channels in sensory neurons is largely based on the study of heterologous systems or rodent tissue, despite evidence that both expression systems and species differences influence these properties. Therefore, we sought to determine the extent to which the biophysical and pharmacological properties of VGSCs were comparable in rat and human sensory neurons. Whole cell patch clamp techniques were used to study Na+ currents in acutely dissociated neurons from human and rat. Our results indicate that while the two major current types, generally referred to as tetrodotoxin (TTX)-sensitive and TTX-resistant were qualitatively similar in neurons from rats and humans, there were several differences that have important implications for drug development as well as our understanding of pain mechanisms.


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