Biology subjects

Hucho, T.

Publications and source records attributed to Hucho, T..

7 recordsLinked to original sources

bioRxiv2026

Suzetrigine-evoked analgesia is potentiated by Nav1.7 null-related opioid mechanisms.

The genetic evidence for an essential role of sodium channel Nav1.7 in human pain conditions is compelling. Unfortunately, potent selective channel blockers of Nav1.7 are not useful analgesics because they have deleterious side effects, particularly on the autonomic nervous system. Here we have evaluated the downstream mechanisms induced by Nav1.7 loss in utero. Nav1.1 compensates for loss of Nav1.7 in sensory neurons and antisense Nav1.1 oligonucleotides diminish excitability in Nav1.7 embryonic null sensory neurons. Enhanced endogenous opioid signalling contributes substantially to analgesia. This is linked to altered gene expression that potentiates opioid signalling through lowered levels of proteins that terminate G-protein signalling (RGS4 and RGS8). There is also enhanced opioid drive through increased enkephalin levels linked to lowered sodium levels in Nav1.7 null neurons. Opioid signalling is the main driver of analgesia, but enhanced potassium channel expression (KCNC4 KCNK2, KCNMB2, KCNAB3) all implicated in pain control, may also contribute to the small level of naloxone-resistant analgesia. These findings suggest a potential new route to analgesia, through mimicking the events at Nav1.7 null sensory neuron terminals. Here we demonstrate potentiation of suzetrigine-evoked analgesia with RGS antagonists alone or in combination with normally inactive doses of morphine in formalin-evoked pain and CFA-induced inflammatory pain. Intriguingly, no analgesia is observed with acute pain. Cancer pain is under investigation. These data are of potential clinical interest.

neuroscience↗

bioRxiv2026

A mechanistic model of protein kinase A dynamics under pro- and anti-nociceptive inputs

Protein kinase A (PKA) is a central integrator of nociceptive signaling, yet a quantitative account of how pro- and anti-nociceptive inputs shape its dynamics remains incomplete. Here, we develop a mechanistic model of PKA activity in nociceptive neurons that explicitly links receptor activation to downstream kinase regulation. Using time-course and dose-response measurements, we infer unknown process parameters and quantify parameter and prediction uncertainties to ensure robust conclusions. The model captures the activation of PKA by serotonin and forskolin and its suppression by opioids. We show how the model can be used for the assessment of alternative circuit topologies, and demonstrate that receptor context and stimulation history reconfigure PKA responsiveness, providing testable predictions for opioid modulation under clinically relevant dosing. This framework offers a principled basis for integrating PKA with broader pain-signaling networks, supports rational exploration of combination therapies, and establishes a general strategy for disentangling neuromodulatory control of kinase activity. Author summaryPain perception is modulated by a complex network of signaling pathways activated by different receptors with opposing effects. A key player in this process is protein kinase A (PKA), whose regulation by both serotonin and opioid receptors is not yet fully understood. In this study, we developed a mathematical model to investigate how these opposing signals affect PKA activity in sensory neurons. After estimating the unknown model parameters from a comprehensive dataset, we were able to quantitatively analyze the dynamic behavior of the system and use it for comparison of alternative circuit topologies. Our model provides a valuable tool for integrating diverse molecular interactions involved in pain processing and could help guide future efforts to develop better treatments for chronic pain and reduce opioid tolerance.

systems biology↗

bioRxiv2026

Senescence-associated Cdkn1a (p21) is upregulated in rodent dorsal root ganglion neurons across lesion-based neuropathic pain models

Senescence of peripheral sensory neurons has recently been associated with increased nociceptive signalling and pain chronification. Whether this association is found across pain conditions and independent study settings remains to be investigated. In this study, we made use of publicly available whole-genome transcriptome data sets on rodent dorsal root ganglion (DRG) tissue to investigate pain-related peripheral sensory neuron senescence across pain models and independent study settings. We focused on Cdkn1a (p21) and Cdkn2a (p16) expression levels as two widely-used senescence markers, and to explore their potential role in peripheral sensory neuron senescence. We found that Cdkn1a but not Cdkn2a RNA is significantly increased across different axotomy- and lesion-based neuropathic pain models, but less consistent in other pain models including inflammatory pain. We observed a sex-dependent effect of Cdkn1a upregulation following nerve injury, with significantly increased Cdkn1a RNA levels in DRG cells from female but not male rats. Lastly, Cdkn1a RNA levels are increased among all DRG neuronal subtypes, seem to reach their maximum three to seven days following nerve injury, and afterwards go back to baseline. These data suggest that Cdkn1a upregulation in DRG neurons is a widespread response to nerve injury that is found across independent study settings. SummaryAnalysis of publicly available whole-genome transcriptome data sets shows that senescence-associated Cdkn1a but not Cdkn2a expression is upregulated in DRG neurons across neuropathic pain models.

neuroscience↗

bioRxiv2025

CaV1.2-dependent excitation-transcription coupling modulates nociception

Peripheral nociceptive sensory neurons integrate various noxious inputs, resulting in local depolarization that triggers the firing of action potentials and thus the sensation of pain. We recently reported that nociceptor depolarization itself initiates signaling by the calcium channel Cav1.2 causing acute hyperalgesia in vivo. However, whether this mechanism initiates excitation-transcription (E-T) coupling and thereby leads to long-lasting modulation of nociceptor activity remains poorly understood. Using high content imaging of dorsal root ganglion (DRG) neurons, we here found that depolarization of nociceptors induces phosphorylation of the transcription factor (TF) cAMP-response element binding protein (CREB), which was affected by inhibition of protein kinase A (PKA) and calcineurin, but not Ca2+/calmodulin-dependent protein kinases. Genetic deletion or pharmacological inhibition of Cav1.2 confirmed its role in calcium-dependent kinase signaling and CREB phosphorylation after depolarization. In line with this, pharmacological modulation of Cav1 channels affected the expression of a subset of depolarization-regulated immediate early genes known to orchestrate a broader transcriptional response. Indeed, RNA-Seq analysis of DRG neurons from mice with a tissue-specific deletion of Cav1.2 in nociceptive sensory neurons (SNS-Cacna1c-/- mice) revealed downregulation of multiple calcium and potassium channel subunits as well as proteins involved in synaptic vesicle release and cell adhesion. Furthermore, repetitive firing of action potentials and release of the neuropeptide CGRP was impaired in Cav1.2-deficient sensory neurons. SNS-Cacna1c-/- mice showed increased sensitivity to noxious heat and exacerbated inflammatory but not neuropathic pain. In conclusion, our data suggest a Cav1.2-dependent E-T coupling mechanism in nociceptors that counteracts nociception in vivo. HighlightsO_LIDepolarization induces Cav1.2- and PKA-dependent phosphorylation of the transcriptional regulator CREB in nociceptors C_LIO_LICav1.2 regulates the expression of depolarization-induced immediate early genes and induces reorganization of the signaling network in nociceptors C_LIO_LICav1.2-deficient nociceptors downregulate multiple ion channel subunits as well as proteins involved in synaptic vesicle release and cell adhesion C_LIO_LICav1.2-deficient nociceptors show impaired depolarization-induced PKA-II signaling, CREB phosphorylation, repetitive firing of action potentials, and release of the neuropeptide CGRP C_LIO_LINociceptor-specific Cav1.2-deficiency in mice increases the sensitivity to noxious heat and exacerbates inflammatory pain C_LI In briefIsensee et al. report that depolarization of nociceptors induces calcium influx through Cav1.2 channels, thereby initiating a signaling cascade that links neuronal excitation to transcriptional regulation of immediate early genes (E-T coupling). Nociceptor-specific knockout of Cav1.2 led to transcriptional changes in nociceptor-specific genes and was associated with impaired depolarization-induced signaling, action potential firing, and neuropeptide release. As the Cav1.2-deficient mice show increased noxious heat sensitivity and exacerbated inflammatory pain, these findings suggest that Cav1.2-dependent E-T coupling mechanism counteracts nociception in vivo.

neuroscience↗

bioRxiv2022

Autophagy regulates neuronal excitability by controlling cAMP/Protein Kinase A signaling

Autophagy provides nutrients during starvation and eliminates detrimental cellular components. However, accumulating evidence indicates that autophagy is not merely a housekeeping process. Here, we show that the protein AuTophaGy 5 (ATG5) functions in neurons to regulate the 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 the cAMP/PKA-dependent phosphorylation of postsynaptic cytoskeletal proteins mediating AMPAR trafficking. Glutamatergic neurons-confined ATG5 deletion 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.

neuroscience↗

bioRxiv2020

Anthrax Toxin as a Molecular Platform to Target Nociceptive Neurons and Modulate Pain

Bacterial toxins are able to act on neurons to modulate signaling and function. Here, we find that nociceptive sensory neurons that mediate pain are enriched in the receptor for anthrax toxins, ANTXR2. Anthrax Edema Toxin (ET) induced cAMP and PKA signaling in Nav1.8+ nociceptive neurons and modulated pain in vivo. Peripherally administered ET mediated mechanical allodynia in naive mice and during B. anthracis infection. Intrathecally administered ET produced analgesic effects, potently blocking pain-like behaviors in multiple mouse models of inflammatory and chronic neuropathic pain. Nociceptor-specific ablation of ANTXR2 attenuated ET-induced signaling and analgesia. Modified anthrax toxin successfully delivered exogenous protein cargo into nociceptive neurons, illustrating utility of the anthrax toxin system as a molecular platform to target pain. ET further induced signaling in human iPSC-derived sensory neurons. Our findings highlight novel interactions between a bacterial toxin and nociceptors that may be utilized for developing new pain therapeutics. SUMMARYANTXR2 expression on nociceptive neurons allows selective targeting and modulation of pain by native and engineered anthrax toxins.

neuroscience↗

bioRxiv2017

Mechanistic hierarchical population model identifies latent causes of cell-to-cell variability

All biological systems exhibit cell-to-cell variability, and this variability often has functional implications. To gain a thorough understanding of biological processes, the latent causes and underlying mechanisms of this variability must be elucidated. Cell populations comprising multiple distinct subpopulations are commonplace in biology, yet no current methods allow the sources of variability between and within individual subpopulations to be identified. This limits the analysis of single-cell data, for example provided by flow cytometry and microscopy. In this study, we present a data-driven modeling framework for the analysis of populations comprising heterogeneous subpopulations. Our approach combines mixture modeling with frameworks for distribution approximation, facilitating the integration of multiple single-cell datasets and the detection of causal differences between and within subpopulations. The computational efficiency of our framework allows hundreds of competing hypotheses to be compared, giving unprecedented depth of a study. We demonstrated the ability of our method to capture multiple levels of heterogeneity in the analyzes of simulated data and data from highly heterogeneous sensory neurons involved in pain initiation. Our approach identified the sources of cell-to-cell variability and revealed mechanisms that underlie the modulation of nerve growth factor-induced Erk1/2 signaling by extracellular scaffolds.

systems biology↗