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1.
Pain Rep ; 9(3): e1155, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38617100

ABSTRACT

Introduction and Objectives: Lipedema is a widespread severe chronic disease affecting mostly women. Characterized by painful bilateral fat accumulation in extremities sparing hands and feet, objective measurement-based diagnosis is currently missing. We tested for characteristic psychometric and/or sensory alterations including pain and for their potential for medical routine diagnosis. Methods: Pain psychometry was assessed using the German Pain Questionnaire. Sensory sensitivity toward painful and nonpainful stimuli was characterized in non-obese lipedema patients and matched controls using the validated quantitative sensory testing (QST) protocol of the German Research Network on Neuropathic Pain. Results: Lipedema patients showed no overt psychometric abnormalities. Pain was reported as somatic rather than psychosomatic aversive. All QST measurements were normal, but the z-score of pressure pain thresholds (PPT) was twofold reduced and the z-score of vibration detection thresholds (VDT) was two and a half times increased. Both thresholds were selectively altered at the affected thigh but not the unaffected hand. Receiver operating characteristic analysis of the combination of PPT and VDT of thigh vs hand into a PVTH score (PPT, VDT, thigh, hand-score) shows high sensitivity and specificity, categorizing correctly 95.8% of the participants as lipedema patients or healthy controls. Bayesian inference analysis corroborated the diagnostic potential of such a combined PVTH score. Conclusion: We propose to assess PPT and VDT at the painful thigh and the pain-free hand. Combination in a PVTH score may allow a convenient lipedema diagnosis early during disease development.

2.
Dermatologie (Heidelb) ; 74(8): 575-579, 2023 Aug.
Article in German | MEDLINE | ID: mdl-37438647

ABSTRACT

Pain, which is a central characteristic of lipedema, allows differentiation from other fat tissue diseases. The analysis of the multiple aspects of pain beyond a quantification of pain scale scores could make molecular disease and therapy mechanisms accessible. Lipedema pain is causally linked to lipedema fat. First robust data show peripheral sensory changes. Tissue weight and systemic inflammation are becoming less likely as causes for the experianced pain. Furthermore, genetics and hormonal influences need to be investigated. Lipedema pain cannot currently be treated with drugs. Physical therapy shows transient relief. Liposuction has been shown to have a long-term effect on pain. The potential of modulating the perception of pain with psychotherapeutic approaches is emerging as a potentially effective new therapeutic approach.


Subject(s)
Lipectomy , Lipedema , Humans , Lipedema/diagnosis , Pain/diagnosis , Lipectomy/adverse effects , Adipose Tissue
3.
Cells ; 12(9)2023 04 25.
Article in English | MEDLINE | ID: mdl-37174648

ABSTRACT

Peripheral neuropathy is a common side effect of cancer treatment with paclitaxel. The mechanisms by which paclitaxel is transported into neurons, which are essential for preventing neuropathy, are not well understood. We studied the uptake mechanisms of paclitaxel into neurons using inhibitors for endocytosis, autophagy, organic anion-transporting polypeptide (OATP) drug transporters, and derivatives of paclitaxel. RT-qPCR was used to investigate the expression levels of OATPs in different neuronal tissues and cell lines. OATP transporters were pharmacologically inhibited or modulated by overexpression and CRISPR/Cas9-knock-out to investigate paclitaxel transport in neurons. Through these experiments, we identified OATP1A1 and OATP1B2 as the primary neuronal transporters for paclitaxel. In vitro inhibition of OATP1A1 and OAT1B2 by glycyrrhizic acid attenuated neurotoxicity, while paclitaxel's antineoplastic effects were sustained in cancer cell lines. In vivo, glycyrrhizic acid prevented paclitaxel-induced toxicity and improved behavioral and electrophysiological measures. This study indicates that a set of OATPs are involved in paclitaxel transport into neurons. The inhibition of OATP1A1 and OATP1B2 holds a promising strategy to prevent paclitaxel-induced peripheral neuropathy.


Subject(s)
Organic Anion Transporters , Peripheral Nervous System Diseases , Humans , Paclitaxel/adverse effects , Glycyrrhizic Acid/pharmacology , Organic Anion Transporters/metabolism , Neurons/metabolism , Membrane Transport Proteins , Peripheral Nervous System Diseases/chemically induced , Peripheral Nervous System Diseases/prevention & control
4.
Pain ; 164(8): 1718-1733, 2023 Aug 01.
Article in English | MEDLINE | ID: mdl-36727909

ABSTRACT

ABSTRACT: Induced pluripotent stem cells (iPSCs) have enabled the generation of various difficult-to-access cell types such as human nociceptors. A key challenge associated with human iPSC-derived nociceptors (hiPSCdNs) is their prolonged functional maturation. While numerous studies have addressed the expression of classic neuronal markers and ion channels in hiPSCdNs, the temporal development of key signaling cascades regulating nociceptor activity has remained largely unexplored. In this study, we used an immunocytochemical high-content imaging approach alongside electrophysiological staging to assess metabotropic and ionotropic signaling of large scale-generated hiPSCdNs across 70 days of in vitro differentiation. During this period, the resting membrane potential became more hyperpolarized, while rheobase, action potential peak amplitude, and membrane capacitance increased. After 70 days, hiPSCdNs exhibited robust physiological responses induced by GABA, pH shift, ATP, and capsaicin. Direct activation of protein kinase A type II (PKA-II) through adenylyl cyclase stimulation with forskolin resulted in PKA-II activation at all time points. Depolarization-induced activation of PKA-II emerged after 35 days of differentiation. However, effective inhibition of forskolin-induced PKA-II activation by opioid receptor agonists required 70 days of in vitro differentiation. Our results identify a pronounced time difference between early expression of functionally important ion channels and emergence of regulatory metabotropic sensitizing and desensitizing signaling only at advanced stages of in vitro cultivation, suggesting an independent regulation of ionotropic and metabotropic signaling. These data are relevant for devising future studies into the development and regulation of human nociceptor function and for defining time windows suitable for hiPSCdN-based drug discovery.


Subject(s)
Induced Pluripotent Stem Cells , Humans , Analgesics, Opioid , Colforsin/pharmacology , Nociception , Sensory Receptor Cells , Ion Channels
5.
EMBO J ; 41(22): e110963, 2022 11 17.
Article in English | MEDLINE | ID: mdl-36217825

ABSTRACT

Autophagy provides nutrients during starvation and eliminates detrimental cellular components. However, accumulating evidence indicates that autophagy is not merely a housekeeping process. Here, by combining mouse models of neuron-specific ATG5 deficiency in either excitatory or inhibitory neurons with quantitative proteomics, high-content microscopy, and live-imaging approaches, we show that autophagy protein ATG5 functions in neurons to regulate cAMP-dependent protein kinase A (PKA)-mediated phosphorylation of a synapse-confined proteome. This function of ATG5 is independent of bulk turnover of synaptic proteins and requires the targeting of PKA inhibitory R1 subunits to autophagosomes. Neuronal loss of ATG5 causes synaptic accumulation of PKA-R1, which sequesters the PKA catalytic subunit and diminishes cAMP/PKA-dependent phosphorylation of postsynaptic cytoskeletal proteins that mediate AMPAR trafficking. Furthermore, ATG5 deletion in glutamatergic neurons augments AMPAR-dependent excitatory neurotransmission and causes the appearance of spontaneous recurrent seizures in mice. Our findings identify a novel role of autophagy in regulating PKA signaling at glutamatergic synapses and suggest the PKA as a target for restoration of synaptic function in neurodegenerative conditions with autophagy dysfunction.


Subject(s)
Neurons , Synapses , Mice , Animals , Synapses/metabolism , Neurons/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , Signal Transduction , Autophagy
6.
Breast Cancer Res ; 24(1): 41, 2022 06 17.
Article in English | MEDLINE | ID: mdl-35715861

ABSTRACT

BACKGROUND: The majority of BRCA1-mutant breast cancers are characterized by a triple-negative phenotype and a basal-like molecular subtype, associated with aggressive clinical behavior. Current treatment options are limited, highlighting the need for the development of novel targeted therapies for this tumor subtype. METHODS: Our group previously showed that EZH2 is functionally relevant in BRCA1-deficient breast tumors and blocking EZH2 enzymatic activity could be a potent treatment strategy. To validate the role of EZH2 as a therapeutic target and to identify new synergistic drug combinations, we performed a high-throughput drug combination screen in various cell lines derived from BRCA1-deficient and -proficient mouse mammary tumors. RESULTS: We identified the combined inhibition of EZH2 and the proximal DNA damage response kinase ATM as a novel synthetic lethality-based therapy for the treatment of BRCA1-deficient breast tumors. We show that the combined treatment with the EZH2 inhibitor GSK126 and the ATM inhibitor AZD1390 led to reduced colony formation, increased genotoxic stress, and apoptosis-mediated cell death in BRCA1-deficient mammary tumor cells in vitro. These findings were corroborated by in vivo experiments showing that simultaneous inhibition of EZH2 and ATM significantly increased anti-tumor activity in mice bearing BRCA1-deficient mammary tumors. CONCLUSION: Taken together, we identified a synthetic lethal interaction between EZH2 and ATM and propose this synergistic interaction as a novel molecular combination for the treatment of BRCA1-mutant breast cancer.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Ataxia Telangiectasia Mutated Proteins , BRCA1 Protein , Breast Neoplasms , Enhancer of Zeste Homolog 2 Protein , Indoles , Protein Kinase Inhibitors , Pyridones , Animals , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Ataxia Telangiectasia Mutated Proteins/antagonists & inhibitors , Ataxia Telangiectasia Mutated Proteins/metabolism , BRCA1 Protein/deficiency , Breast Neoplasms/drug therapy , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Line, Tumor , Enhancer of Zeste Homolog 2 Protein/antagonists & inhibitors , Enhancer of Zeste Homolog 2 Protein/genetics , Enhancer of Zeste Homolog 2 Protein/metabolism , Female , Humans , Indoles/pharmacology , Mammary Neoplasms, Experimental/drug therapy , Mammary Neoplasms, Experimental/metabolism , Mammary Neoplasms, Experimental/pathology , Mice , Protein Kinase Inhibitors/pharmacology , Pyridones/pharmacology , Synthetic Lethal Mutations
7.
Gigascience ; 112022 05 18.
Article in English | MEDLINE | ID: mdl-35640874

ABSTRACT

Venoms have evolved >100 times in all major animal groups, and their components, known as toxins, have been fine-tuned over millions of years into highly effective biochemical weapons. There are many outstanding questions on the evolution of toxin arsenals, such as how venom genes originate, how venom contributes to the fitness of venomous species, and which modifications at the genomic, transcriptomic, and protein level drive their evolution. These questions have received particularly little attention outside of snakes, cone snails, spiders, and scorpions. Venom compounds have further become a source of inspiration for translational research using their diverse bioactivities for various applications. We highlight here recent advances and new strategies in modern venomics and discuss how recent technological innovations and multi-omic methods dramatically improve research on venomous animals. The study of genomes and their modifications through CRISPR and knockdown technologies will increase our understanding of how toxins evolve and which functions they have in the different ontogenetic stages during the development of venomous animals. Mass spectrometry imaging combined with spatial transcriptomics, in situ hybridization techniques, and modern computer tomography gives us further insights into the spatial distribution of toxins in the venom system and the function of the venom apparatus. All these evolutionary and biological insights contribute to more efficiently identify venom compounds, which can then be synthesized or produced in adapted expression systems to test their bioactivity. Finally, we critically discuss recent agrochemical, pharmaceutical, therapeutic, and diagnostic (so-called translational) aspects of venoms from which humans benefit.


Subject(s)
Proteomics , Venoms , Animals , Research , Snakes/genetics , Transcriptome , Venoms/chemistry , Venoms/genetics
8.
Nat Neurosci ; 25(2): 168-179, 2022 02.
Article in English | MEDLINE | ID: mdl-34931070

ABSTRACT

Bacterial products can act on neurons to alter signaling and function. In the present study, we found that dorsal root ganglion (DRG) sensory neurons are enriched for ANTXR2, the high-affinity receptor for anthrax toxins. Anthrax toxins are composed of protective antigen (PA), which binds to ANTXR2, and the protein cargoes edema factor (EF) and lethal factor (LF). Intrathecal administration of edema toxin (ET (PA + EF)) targeted DRG neurons and induced analgesia in mice. ET inhibited mechanical and thermal sensation, and pain caused by formalin, carrageenan or nerve injury. Analgesia depended on ANTXR2 expressed by Nav1.8+ or Advillin+ neurons. ET modulated protein kinase A signaling in mouse sensory and human induced pluripotent stem cell-derived sensory neurons, and attenuated spinal cord neurotransmission. We further engineered anthrax toxins to introduce exogenous protein cargoes, including botulinum toxin, into DRG neurons to silence pain. Our study highlights interactions between a bacterial toxin and nociceptors, which may lead to the development of new pain therapeutics.


Subject(s)
Anthrax , Bacillus anthracis , Bacterial Toxins , Induced Pluripotent Stem Cells , Animals , Anthrax/microbiology , Anthrax/therapy , Bacillus anthracis/metabolism , Bacterial Toxins/metabolism , Ganglia, Spinal/metabolism , Humans , Induced Pluripotent Stem Cells/metabolism , Mice , Nociceptors/metabolism , Pain , Receptors, Peptide/metabolism
9.
Sci Transl Med ; 13(619): eabh1314, 2021 11 10.
Article in English | MEDLINE | ID: mdl-34757807

ABSTRACT

The voltage-gated sodium NaV1.7 channel, critical for sensing pain, has been actively targeted by drug developers; however, there are currently no effective and safe therapies targeting NaV1.7. Here, we tested whether a different approach, indirect NaV1.7 regulation, could have antinociceptive effects in preclinical models. We found that preventing addition of small ubiquitin-like modifier (SUMO) on the NaV1.7-interacting cytosolic collapsin response mediator protein 2 (CRMP2) blocked NaV1.7 functions and had antinociceptive effects in rodents. In silico targeting of the SUMOylation site in CRMP2 (Lys374) identified >200 hits, of which compound 194 exhibited selective in vitro and ex vivo NaV1.7 engagement. Orally administered 194 was not only antinociceptive in preclinical models of acute and chronic pain but also demonstrated synergy alongside other analgesics­without eliciting addiction, rewarding properties, or neurotoxicity. Analgesia conferred by 194 was opioid receptor dependent. Our results demonstrate that 194 is a first-in-class protein-protein inhibitor that capitalizes on CRMP2-NaV1.7 regulation to deliver safe analgesia in rodents.


Subject(s)
Chronic Pain , NAV1.7 Voltage-Gated Sodium Channel , Analgesics/pharmacology , Analgesics/therapeutic use , Animals , NAV1.7 Voltage-Gated Sodium Channel/metabolism , Rodentia/metabolism , Sumoylation
10.
Hum Genet ; 140(12): 1679-1693, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34545459

ABSTRACT

The highly conserved YrdC domain-containing protein (YRDC) interacts with the well-described KEOPS complex, regulating specific tRNA modifications to ensure accurate protein synthesis. Previous studies have linked the KEOPS complex to a role in promoting telomere maintenance and controlling genome integrity. Here, we report on a newborn with a severe neonatal progeroid phenotype including generalized loss of subcutaneous fat, microcephaly, growth retardation, wrinkled skin, renal failure, and premature death at the age of 12 days. By trio whole-exome sequencing, we identified a novel homozygous missense mutation, c.662T > C, in YRDC affecting an evolutionary highly conserved amino acid (p.Ile221Thr). Functional characterization of patient-derived dermal fibroblasts revealed that this mutation impairs YRDC function and consequently results in reduced t6A modifications of tRNAs. Furthermore, we established and performed a novel and highly sensitive 3-D Q-FISH analysis based on single-telomere detection to investigate the impact of YRDC on telomere maintenance. This analysis revealed significant telomere shortening in YRDC-mutant cells. Moreover, single-cell RNA sequencing analysis of YRDC-mutant fibroblasts revealed significant transcriptome-wide changes in gene expression, specifically enriched for genes associated with processes involved in DNA repair. We next examined the DNA damage response of patient's dermal fibroblasts and detected an increased susceptibility to genotoxic agents and a global DNA double-strand break repair defect. Thus, our data suggest that YRDC may affect the maintenance of genomic stability. Together, our findings indicate that biallelic variants in YRDC result in a developmental disorder with progeroid features and might be linked to increased genomic instability and telomere shortening.


Subject(s)
Developmental Disabilities/genetics , GTP-Binding Proteins/genetics , Progeria/genetics , RNA-Binding Proteins/genetics , Alleles , Consanguinity , DNA Damage , Developmental Disabilities/pathology , Genome, Human , Genomic Instability , Homozygote , Humans , Infant, Newborn , Male , Mutation , Pedigree , Progeria/pathology , RNA, Transfer/genetics , Sequence Analysis, RNA , Telomere Shortening
11.
J Cell Biol ; 220(10)2021 10 04.
Article in English | MEDLINE | ID: mdl-34431981

ABSTRACT

Depolarization drives neuronal plasticity. However, whether depolarization drives sensitization of peripheral nociceptive neurons remains elusive. By high-content screening (HCS) microscopy, we revealed that depolarization of cultured sensory neurons rapidly activates protein kinase A type II (PKA-II) in nociceptors by calcium influx through CaV1.2 channels. This effect was modulated by calpains but insensitive to inhibitors of cAMP formation, including opioids. In turn, PKA-II phosphorylated Ser1928 in the distal C terminus of CaV1.2, thereby increasing channel gating, whereas dephosphorylation of Ser1928 involved the phosphatase calcineurin. Patch-clamp and behavioral experiments confirmed that depolarization leads to calcium- and PKA-dependent sensitization of calcium currents ex vivo and local peripheral hyperalgesia in the skin in vivo. Our data suggest a local activity-driven feed-forward mechanism that selectively translates strong depolarization into further activity and thereby facilitates hypersensitivity of nociceptor terminals by a mechanism inaccessible to opioids.


Subject(s)
Calcium Channels, L-Type/metabolism , Cyclic AMP-Dependent Protein Kinase Type II/metabolism , Nociceptors/metabolism , Animals , Male , Rats , Rats, Sprague-Dawley
12.
Cell Death Dis ; 12(6): 530, 2021 05 24.
Article in English | MEDLINE | ID: mdl-34031359

ABSTRACT

Non-coding RNA from pericentromeric satellite repeats are involved in stress-dependent splicing processes, maintenance of heterochromatin, and are required to protect genome stability. Here we show that the long non-coding satellite III RNA (SatIII) generates resistance against the topoisomerase IIa (TOP2A) inhibitor etoposide in lung cancer. Because heat shock conditions (HS) protect cells against the toxicity of etoposide, and SatIII is significantly induced under HS, we hypothesized that the protective effect could be traced back to SatIII. Using genome methylation profiles of patient-derived xenograft mouse models we show that the epigenetic modification of the SatIII DNA locus and the resulting SatIII expression predict chemotherapy resistance. In response to stress, SatIII recruits TOP2A to nuclear stress bodies, which protects TOP2A from a complex formation with etoposide and results in decreased DNA damage after treatment. We show that BRD4 inhibitors reduce the expression of SatIII, restoring etoposide sensitivity.


Subject(s)
Drug Resistance, Neoplasm/genetics , Etoposide/therapeutic use , RNA, Long Noncoding/physiology , Animals , Antineoplastic Agents/pharmacology , Cell Cycle Proteins/antagonists & inhibitors , Centromere/genetics , Centromere/metabolism , DNA Methylation/physiology , DNA Topoisomerases, Type II/drug effects , DNA Topoisomerases, Type II/genetics , DNA Topoisomerases, Type II/metabolism , Drug Resistance, Neoplasm/drug effects , Gene Expression Regulation, Neoplastic/drug effects , HEK293 Cells , HeLa Cells , Humans , Male , Mice, Inbred NOD , Mice, SCID , Poly-ADP-Ribose Binding Proteins/drug effects , Poly-ADP-Ribose Binding Proteins/genetics , Poly-ADP-Ribose Binding Proteins/metabolism , RNA, Long Noncoding/genetics , Transcription Factors/antagonists & inhibitors , Tumor Cells, Cultured , Xenograft Model Antitumor Assays
13.
Shock ; 55(5): 620-629, 2021 05 01.
Article in English | MEDLINE | ID: mdl-32433203

ABSTRACT

BACKGROUND: Knowledge about the neuroinflammatory state during months after sudden cardiac arrest is scarce. Neuroinflammation is mediated by cells that express the 18 kDa translocator protein (TSPO). We determined the time course of TSPO-expressing cells in a rat model of sudden cardiac arrest using longitudinal in vivo positron emission tomography (PET) imaging with the TSPO-specific tracer [18F]DAA1106 over a period of 6 months. METHODS: Five male Sprague Dawley rats were resuscitated from 6 min sudden cardiac arrest due to ventricular fibrillation, three animals served as shams. PET measurements were performed on day 5, 8, 14, 90, and 180 after intervention. Magnetic resonance imaging was performed on day 140. Imaging was preceded by Barnes Maze spatial memory testing on day 3, 13, 90, and 180. Specificity of [18F]DAA1106 binding was confirmed by Iba-1 immunohistochemistry. RESULTS: [18F]DAA1106 accumulated bilaterally in the dorsal hippocampus of all sudden cardiac arrest animals on all measured time points. Immunohistochemistry confirmed Iba-1 expressing cells in the hippocampal CA1 region. The number of Iba-1-immunoreactive objects per mm2 was significantly correlated with [18F]DAA1106 uptake. Additionally, two of the five sudden cardiac arrest rats showed bilateral TSPO-expression in the striatum that persisted until day 180. In Barnes Maze, the relative time spent in the target quadrant negatively correlates with dorsal hippocampal [18F]DAA1106 uptake on day 14 and 180. CONCLUSIONS: After sudden cardiac arrest, TSPO remains expressed over the long-term. Sustainable treatment options for neuroinflammation may be considered to improve cognitive functions after sudden cardiac arrest.


Subject(s)
Carrier Proteins/biosynthesis , Heart Arrest/diagnostic imaging , Heart Arrest/metabolism , Positron-Emission Tomography , Receptors, GABA-A/biosynthesis , Acetamides , Animals , Male , Phenyl Ethers , Rats , Rats, Sprague-Dawley , Time Factors
14.
FEBS J ; 288(7): 2418-2435, 2021 04.
Article in English | MEDLINE | ID: mdl-33051988

ABSTRACT

Venoms are a rich source of highly specific toxins, which allow the identification of novel therapeutic targets. We have now applied high content screening (HCS) microscopy to identify toxins that modulate pain sensitization signaling in primary sensory neurons of rat and elucidated the underlying mechanism. A set of venoms and fractions thereof were analyzed for their ability to activate type II protein kinase A (PKA-II) and extracellular signal-regulated kinases (ERK1/2). We identified MeuNaTxα-1, a sodium channel-selective scorpion α-toxin from Mesobuthus eupeus, which affected both PKA-II and ERK1/2. Recombinant MeuNaTxα-1 showed identical activity to the native toxin on mammalian voltage-gated sodium channels expressed in Xenopus laevis oocytes and induced thermal hyperalgesia in adult mice. The effect of MeuNaTxα-1 on sensory neurons was dose-dependent and tetrodotoxin-sensitive. Application of inhibitors and toxin mutants with altered sodium channel selectivity demonstrated that signaling activation in sensory neurons depends on NaV 1.2 isoform. Accordingly, the toxin was more potent in neurons from newborn rats, where NaV 1.2 is expressed at a higher level. Our results demonstrate that HCS microscopy-based monitoring of intracellular signaling is a novel and powerful tool to identify and characterize venoms and their toxins affecting sensory neurons.


Subject(s)
Cyclic AMP-Dependent Protein Kinase Type II/genetics , NAV1.2 Voltage-Gated Sodium Channel/genetics , Pain/genetics , Voltage-Gated Sodium Channels/genetics , Animals , Animals, Newborn , Humans , Hyperalgesia/genetics , Hyperalgesia/pathology , MAP Kinase Signaling System/drug effects , Mice , Oocytes/drug effects , Oocytes/growth & development , Rats , Scorpion Venoms/chemistry , Scorpion Venoms/pharmacology , Scorpions/chemistry , Sensory Receptor Cells , Xenopus laevis/growth & development
15.
J Neurochem ; 157(6): 1821-1837, 2021 06.
Article in English | MEDLINE | ID: mdl-32885411

ABSTRACT

Hyperalgesic priming is characterized by enhanced nociceptor sensitization by pronociceptive mediators, prototypically PGE2 . Priming has gained interest as a mechanism underlying the transition to chronic pain. Which stimuli induce priming and what cellular mechanisms are employed remains incompletely understood. In adult male rats, we present the cytokine Oncostatin M (OSM), a member of the IL-6 family, as an inducer of priming by a novel mechanism. We used a high content microscopy based approach to quantify the activation of endogenous PKA-II and ERK of thousands sensory neurons in culture. Incubation with OSM increased and prolonged ERK activation by agents that increase cAMP production such as PGE2 , forskolin, and cAMP analogs. These changes were specific to IB4/CaMKIIα positive neurons, required protein translation, and increased cAMP-to-ERK signaling. In both, control and OSM-treated neurons, cAMP/ERK signaling involved RapGEF2 and PKA but not Epac. Similar enhancement of cAMP-to-ERK signaling could be induced by GDNF, which acts mostly on IB4/CaMKIIα-positive neurons, but not by NGF, which acts mostly on IB4/CaMKIIα-negative neurons. In vitro, OSM pretreatment rendered baseline TTX-R currents ERK-dependent and switched forskolin-increased currents from partial to full ERK-dependence in small/medium sized neurons. In summary, priming induced by OSM uses a novel mechanism to enhance and prolong coupling of cAMP/PKA to ERK1/2 signaling without changing the overall pathway structure.


Subject(s)
Cyclic AMP-Dependent Protein Kinases/metabolism , Cyclic AMP/metabolism , Guanine Nucleotide Exchange Factors/metabolism , Hyperalgesia/metabolism , MAP Kinase Signaling System/drug effects , Oncostatin M/toxicity , Animals , Antineoplastic Agents/toxicity , Humans , Hyperalgesia/chemically induced , MAP Kinase Signaling System/physiology , Male , Mice , Rats , Rats, Sprague-Dawley
16.
Clin Nucl Med ; 46(1): 69-70, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33208621

ABSTRACT

A 74-year-old man with a history of prostate cancer with proven osseous metastatic disease underwent Ga-prostate-specific membrane antigen (PSMA) PET/CT under antiandrogen therapy. The scan revealed a long segment of increased PSMA tracer uptake within the right sciatic nerve, which appeared edematous and swollen, and the respective ganglia. Clinically, the patient suffered from pain and paresis in the right leg. As infiltration of a long segment of a single nerve seems unlikely, primarily neuronal disease such as neuritis (induced by metastases or radiotherapy) was considered. The observed uptake of PSMA-targeting PET tracers may then represent a peripheral nerve disorder.


Subject(s)
Edetic Acid/analogs & derivatives , Ganglia/metabolism , Peripheral Nerves/metabolism , Positron Emission Tomography Computed Tomography , Aged , Biological Transport , Bone Neoplasms/secondary , Edetic Acid/metabolism , Ganglia/diagnostic imaging , Ganglia/pathology , Humans , Male , Peripheral Nerves/diagnostic imaging , Peripheral Nerves/pathology , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology
17.
J Integr Med ; 18(5): 425-433, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32732108

ABSTRACT

OBJECTIVE: Osteoarthritis is a degenerative disease that affects synovial joints. Micro-injuries of articular structures initiate inflammatory processes, leading to persistent pain. Due to various risk factors, osteoarthritis is often diagnosed in multimorbid patients. This makes pain management one of the key challenges, with a consistent need for new therapeutic strategies. Hence, complementary and integrative methods such as hirudotherapy have become increasingly important, even though their mechanisms of action are not entirely understood. METHODS: We retrospectively analyzed the longitudinal effect of a single leech application on osteoarthritic joints in a heterogenic cohort of 24 cases with various chronic pain syndromes. We assessed articular pain intensity ratings and movability of the treated joint after one-time leeching for up to 12 months. We further investigated the effect of hirudotherapy on the systemic pain status and multimodal treatment strategies of the patients. RESULTS: There was a significant reduction in pain intensity ratings at the joint of leech application for up to 12 months after treatment. The improvements in pain intensities were independent of the form of osteoarthritis treated. In addition, we saw a considerable enhancement in local movability of the treated joint. Hirudotherapy did not seem to influence the systemic pain status as well as the previously established individualized multimodal treatment model of the patients. CONCLUSION: Leeching as an adjuvant therapy has a great potential especially in terms of safety and long-term outcome.


Subject(s)
Arthritis/therapy , Chronic Pain , Leeching , Chronic Pain/therapy , Humans , Retrospective Studies , Treatment Outcome
18.
Sci Rep ; 9(1): 16272, 2019 11 07.
Article in English | MEDLINE | ID: mdl-31700036

ABSTRACT

The α2δ-1 subunit of voltage-gated calcium channels binds to gabapentin and pregabalin, mediating the analgesic action of these drugs against neuropathic pain. Extracellular matrix proteins from the thrombospondin (TSP) family have been identified as ligands of α2δ-1 in the CNS. This interaction was found to be crucial for excitatory synaptogenesis and neuronal sensitisation which in turn can be inhibited by gabapentin, suggesting a potential role in the pathogenesis of neuropathic pain. Here, we provide information on the biochemical properties of the direct TSP/α2δ-1 interaction using an ELISA-style ligand binding assay. Our data reveal that full-length pentameric TSP-4, but neither TSP-5/COMP of the pentamer-forming subgroup B nor TSP-2 of the trimer-forming subgroup A directly interact with a soluble variant of α2δ-1 (α2δ-1S). Interestingly, this interaction is not inhibited by gabapentin on a molecular level and is not detectable on the surface of HEK293-EBNA cells over-expressing α2δ-1 protein. These results provide biochemical evidence that supports a specific role of TSP-4 among the TSPs in mediating the binding to neuronal α2δ-1 and suggest that gabapentin does not directly target TSP/α2δ-1 interaction to alleviate neuropathic pain.


Subject(s)
Calcium Channels, L-Type/metabolism , Gabapentin/metabolism , Thrombospondins/metabolism , Enzyme-Linked Immunosorbent Assay , HEK293 Cells , Humans , Ligands , Mass Spectrometry , Membrane Proteins/chemistry , Membrane Proteins/metabolism
19.
Cancer Res ; 79(19): 4855-4868, 2019 Oct 01.
Article in English | MEDLINE | ID: mdl-31405847

ABSTRACT

The advent of molecularly targeted therapeutic agents has opened a new era in cancer therapy. However, many tumors rely on nondruggable cancer-driving lesions. In addition, long-lasting clinical benefits from single-agent therapies rarely occur, as most of the tumors acquire resistance over time. The identification of targeted combination regimens interfering with signaling through oncogenically rewired pathways provides a promising approach to enhance efficacy of single-agent-targeted treatments. Moreover, combination drug therapies might overcome the emergence of drug resistance. Here, we performed a focused flow cytometry-based drug synergy screen and identified a novel synergistic interaction between GLUT1-mediated glucose transport and the cell-cycle checkpoint kinases ATR and CHK1. Combined inhibition of CHK1/GLUT1 or ATR/GLUT1 robustly induced apoptosis, particularly in RAS-mutant cancer cells. Mechanistically, combined inhibition of ATR/CHK1 and GLUT1 arrested sensitive cells in S-phase and led to the accumulation of genotoxic damage, particularly in S-phase. In vivo, simultaneous inhibition of ATR and GLUT1 significantly reduced tumor volume gain in an autochthonous mouse model of KrasG12D -driven soft tissue sarcoma. Taken together, these findings pave the way for combined inhibition of GLUT1 and ATR/CHK1 as a therapeutic approach for KRAS-driven cancers. SIGNIFICANCE: Dual targeting of the DNA damage response and glucose transport synergistically induces apoptosis in KRAS-mutant cancer, suggesting this combination treatment for clinical validation in KRAS-stratified tumor patients.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Ataxia Telangiectasia Mutated Proteins/antagonists & inhibitors , Checkpoint Kinase 1/antagonists & inhibitors , Glucose Transporter Type 1/antagonists & inhibitors , Neoplasms, Experimental/pathology , Animals , Apoptosis/drug effects , Benzodiazepinones/pharmacology , Cell Line, Tumor , Drug Screening Assays, Antitumor , Drug Synergism , Humans , Hydroxybenzoates/pharmacology , Mice , Mice, Nude , Molecular Targeted Therapy/methods , Mutation , Proto-Oncogene Proteins p21(ras)/genetics , Pyrazoles/pharmacology , Quinazolines/pharmacology , Xenograft Model Antitumor Assays
20.
Methods Mol Biol ; 1987: 111-124, 2019.
Article in English | MEDLINE | ID: mdl-31028677

ABSTRACT

Studying TRP channel expressing nociceptors requires the identification of the respective subpopulations as well as the quantification of dynamic cellular events. However, the heterogeneity of sensory neurons and associated nonneuronal cells demands the analysis of large numbers of cells to reflect the distribution of entire populations. Here we report a detailed workflow how to apply high-content screening (HCS) microscopy to signaling events in TRPV1-positive neurons as well as an approach to use the selective elimination of TRPV1 positive cells from dissociated rat sensory ganglia as base for transcriptomic analysis of TRPV1-positive cells and/or as control for TRPV1 antibody specificity.


Subject(s)
Sensory Receptor Cells/metabolism , TRPV Cation Channels/metabolism , Animals , Cells, Cultured , Fluorescent Antibody Technique/methods , Male , Mice, Inbred C57BL , Microscopy/methods , Microscopy, Fluorescence , Nociceptors/metabolism , Rats , Rats, Sprague-Dawley , TRPV Cation Channels/immunology
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