Kolber, B. | bioRxiv Science

bioRxiv2025

Amygdalar Calcitonin Gene-Related Peptide Driven Effects of Cold Sensitivity Induced by Peripheral Neuropathy in Mice

The central nucleus of the amygdala (CeA) is a critical regulator of nociception, and its role in pain modulation depends on factors such as hemispheric location, neuropeptide release, and experimental model. Calcitonin gene-related peptide (CGRP) is a potent neuropeptide modulator within the CeA. Previous research has demonstrated its CeA nociceptive role in migraine, visceral, arthritic, and inflammatory pain murine models. The contribution of CeA CGRP to neuropathic pain is unclear. This study examined the effects of CGRP and its receptor antagonist, CGRP 8-37, in the CeA on mechanical and cold sensitivity in two mouse models of neuropathic pain: chemotherapy-induced peripheral neuropathy (CIPN) mediated by paclitaxel (PTX) and injury-induced neuropathy through the spared nerve injury (SNI) model. Mechanical and cold sensitivity were measured using the hindpaw von Frey and topical acetone drop assays, respectively. Neither CGRP nor CGRP 8-37 in the CeA had any significant effect on mechanical sensitivity in either neuropathic pain model. In the SNI-treated mice, CGRP infusion into either the left or right CeA reduced cold sensitivity in the left and right SNI-treated hindpaw, while CGRP 8-37 infusion into the left or right CeA increased cold sensitivity in the right SNI-treated hindpaw only. In PTX-treated mice, CGRP infusion into the left or right CeA decreased cold sensitivity of the contralateral paw only. These results suggest that CGRP in the CeA influences pain modulation in a complex manner that depends not only on the hemisphere and injury site, but also on the underlying cause of the neuropathic condition. PERSPECTIVEThis article presents the anti-nociceptive properties of calcitonin gene-related peptide (CGRP) signaling within the central nucleus of the amygdala during neuropathic pain-like conditions in mice. This dataset can serve to guide novel drug development for treating chronic neuropathic pain conditions. HIGHLIGHTSO_LILateralization of the central nucleus of the amygdala (CeA) is pain-model dependent C_LIO_LICGRP signaling within the CeA is correlated with decreased cold sensitivity C_LIO_LIDifferent neuropathic etiologies yield differences in CGRP responsiveness C_LI

neuroscience↗

bioRxiv2024

Profiling Human iPSC-Derived Sensory Neurons for Analgesic Drug Screening Using a Multi-Electrode Array

Chronic pain is a major global health issue, yet effective treatments are limited by poor translation from preclinical studies to humans. To address this, we developed a high-content screening (HCS) platform for analgesic discovery using hiPSC-derived nociceptors. These cells were cultured on multi-well micro-electrode arrays to monitor activity, achieving nearly 100% active electrodes by week two, maintaining stable activity for at least two weeks. After maturation (28 days), we exposed the nociceptors to various drugs, assessing their effects on neuronal activity, with excellent assay performance (Z values >0.5). Pharmacological tests showed responses to analgesic targets, including ion channels (Nav, Cav, Kv, TRPV1), neurotransmitter receptors (AMPAR, GABA-R), and kinase inhibitors (tyrosine, JAK1/2). Transcriptomic analysis confirmed the presence of these drug targets, although expression levels varied compared to primary human dorsal root ganglion cells. This HCS platform facilitates the rapid discovery of novel analgesics, reducing the risk of preclinical-to-human translation failure. MotivationChronic pain affects approximately 1.5 billion people worldwide, yet effective treatments remain elusive. A significant barrier to progress in analgesic drug discovery is the limited translation of preclinical findings to human clinical outcomes. Traditional rodent models, although widely used, often fail to accurately predict human responses, while human primary tissues are limited by scarcity, technical difficulties, and ethical concerns. Recent advancements have identified human induced pluripotent stem cell (hiPSC)-derived nociceptors as promising alternatives; however, current differentiation protocols produce cells with inconsistent and physiologically questionable phenotypes. To address these challenges, our study introduces a novel high-content screening (HCS) platform using hiPSC-derived nociceptors cultured on multi-well micro-electrode arrays (MEAs). The "Anatomic" protocol, used to generate these nociceptors, ensures cells with transcriptomic profiles closely matching human primary sensory neurons. Our platform achieves nearly 100% active electrode yield within two weeks and demonstrates sustained, stable activity over time. Additionally, robust Z factor analysis (exceeding 0.5) confirms the platforms reliability, while pharmacological validation establishes the functional expression of critical analgesic targets. This innovative approach improves both the efficiency and clinical relevance of analgesic drug screening, potentially bridging the translational gap between preclinical studies and human clinical trials, and offering new hope for effective pain management.

neuroscience↗