Biology subjects

Goodwin, G. L.

Publications and source records attributed to Goodwin, G. L..

5 recordsLinked to original sources

bioRxiv2026

LIF is a pro-algesic mediator in human and mouse models of arthritis-related pain

Purpose: Emerging clinical and experimental data suggest that JAK inhibitors (JAKi) are effective in reducing pain in Rheumatoid Arthritis (RA). We recently showed that JAK/STAT signalling cytokines, specifically IL-6, LIF and IL-11, are present in the RA joint and can act directly on human induced pluripotent stem cell (iPSC) derived sensory neurons by increasing their STAT3 phosphorylation (pSTAT3) levels and expression of select pain-relevant genes. In this study, we determined that LIF is the most consequential cytokine out of the three, altering neuronal signalling, outgrowth and pain-like behaviours in in vitro and in vivo models of arthritis. Methods: Human iPSC-derived sensory neurons were stimulated with RA synovial fluid (SF) or with cytokine-treated RA synovial fibroblast conditioned media (CM) in the absence or presence of anti-cytokine antibodies. pSTAT3 and pSTAT1 levels, and gene expression patterns, were assessed by Western blot and RNA-sequencing (RNA-seq). The immortalised dorsal root ganglion (DRG)-derived cell line (HD 10.6) was assessed for LIF-induced JAK/STAT signalling in addition to neurite outgrowth assays as a functional readout of the sensory neurons. Lastly, mouse models were used to assess pain-related behaviours in vivo. Results: LIF was found to be consistently present in the SF from painful joints from individuals with inflammatory arthritis. Western blotting revealed that the addition of RA SF to iPSC-derived sensory neurons led to LIF-dependent induction of pSTAT3 and pSTAT1, while RNA-seq demonstrated that LIF alters the transcriptome of sensory neurons more prominently than IL-6 and IL-11, up-regulating signature genes related to peripheral neuron sensitization, such as TRPV1, NTRK1, BDNF, HRH1 and SCN10A. Similarly, cytokine-treated fibroblast conditioned media was shown to induce neuronal pSTAT3 and pSTAT1 and upregulate expression of BDNF, HRH1 and VGF in a LIF-dependent manner. Additionally, the immortalised dorsal root ganglion (DRG)-derived cell line (HD 10.6), which also exhibited LIF-induced pSTAT1 and pSTAT3, showed increased neurite outgrowth after axotomy when treated with LIF. Finally, in a mouse model of inflammatory arthritis, LIF was shown to be significantly increased in the affected joint. Furthermore, intraarticular injection of LIF into a healthy mouse knee resulted in increased responsiveness to painful pressure stimuli in that joint. Conclusions: Our data indicate that LIF may be a pro-algesic mediator and a possible therapeutic target to improve pain management in individuals living with inflammatory arthritis.

neuroscience↗

bioRxiv2025

In vivo calcium imaging shows that dorsal root ganglion stimulation predominantly activates large-sized sensory neurons in mice

Dorsal root ganglion (DRG) stimulation is an effective treatment for patients with refractory neuropathic pain. However, the exact mechanisms through which DRG stimulation exerts its analgesic effects, especially in relation to the recruitment of different soma types within the DRG, remains largely unknown. Here, we examined the effect of DRG stimulation (20Hz) on sensory neuron soma recruitment and neuronal responses induced by mechanical hind paw stimulation using in vivo calcium imaging in mice. GCaMP6s was delivered to sensory neurons via an adeno-associated viral vector of serotype 9 (AAV9) injected subcutaneously at P2-5. In adult mice, a stimulation electrode was placed over the L4 DRG, and in vivo calcium imaging was performed. The proportion of responsive neurons and response magnitude was assessed during 30-60 seconds of DRG stimulation at different stimulation amplitudes (33%, 50%, 66%, 80%, 100% of motor threshold (MT)) for small, medium and large-sized subpopulations. In a second experiment, the effect of 30 minutes of DRG stimulation was assessed at 66% MT on neuronal responses induced by mechanical hind paw stimulation during and following DRG stimulation. We show that 20Hz DRG stimulation at clinically relevant parameters mainly activates large-size sensory neurons in mice, both in terms of the proportion of neurons responding as well as response magnitude. There was a small decrease in the proportion of neurons responding to mechanical stimulation during DRG stimulation, which did not recover 30 mins after stimulation had been switched off. By contrast, DRG stimulation did not alter the response magnitude of responding neurons.

neuroscience↗

bioRxiv2024

Using in vivo calcium imaging and home cage behavioural analysis to study pain in mouse models of rheumatoid- and osteo-arthritis

BackgroundStudying pain in rodent models of arthritis is challenging. For example, assessing functional changes in joints neurons is challenging due to their relative scarcity amongst all sensory neurons. Additionally, studying pain behaviors in rodent models of arthritis poses its own set of difficulties. Commonly used tests, such as static weight-bearing, often require restraint, which can induce stress and consequently alter nociception. The aim of this study was to evaluate two emerging techniques for investigating joint pain in mouse models of rheumatoid and osteoarthritis: In vivo calcium imaging to monitor joint afferent activity and group-housed home cage monitoring to assess pain-like behaviors. Specifically, we examined whether there was increased spontaneous activity in joint afferents and reduced locomotor activity following induction of arthritis. MethodsAntigen induced arthritis (AIA) was used to model rheumatoid arthritis and partial medial meniscectomy (PMX) was used to model osteoarthritis. Group-housed home cage monitoring was used to assess locomotor behavior in all mice, and weight bearing was assessed in PMX mice. In vivo calcium imaging with GCaMP6s was used to monitor spontaneous activity in L4 ganglion joint neurons retrogradely labelled with fast blue 2 days following AIA and 13-15 weeks following PMX model induction. Cartilage degradation was assessed in knee joint sections stained with Safranin O and fast green in PMX mice. ResultsAntigen induced arthritis produced knee joint swelling and PMX caused degeneration of articular cartilage in the knee. In the first 46 hours following AIA, mice travelled less distance and were less mobile compared to their control cage mates. In contrast, no such differences were found between PMX and sham mice when measured between 4-12 weeks post-surgery. A larger fraction of joint neurons showed spontaneous activity in AIA but not PMX mice. Spontaneous activity was mostly displayed by medium-sized neurons in AIA mice and was not correlated with any of the home cage behaviors. ConclusionGroup-housed home cage monitoring revealed locomotor changes in AIA mice, but not PMX mice (with n=10/group). In vivo calcium imaging can be used to assess activity in multiple retrogradely labelled joint afferents and revealed increased spontaneous activity in AIA but not PMX mice.

neuroscience↗

bioRxiv2023

Assessing spontaneous sensory neuron activity using in vivo calcium imaging

Heightened spontaneous activity in sensory neurons is often reported in individuals living with chronic pain. It is possible to study this activity in rodents using electrophysiology, but these experiments require great skill and can be prone to bias. Here, we have examined whether in vivo calcium imaging with GCaMP6s can be used as an alternative approach. We show that spontaneously active calcium transients can be visualised in the fourth lumbar dorsal root ganglion (L4 DRG) via in vivo imaging in a mouse model of pain. Application of lidocaine to the nerve, between the inflamed site and the DRG, silenced spontaneous firing and revealed the true baseline level of calcium for spontaneously active neurons. We used this data to train a machine leaning algorithm to predict when a neuron is spontaneously active. We show that our algorithm is accurate in two different models of pain: intraplantar Complete Freunds Adjuvant and antigen-induced arthritis, with accuracies of 90.0% +/-1.2 and 85.9 % +/-2.1, respectively, assessed against visual inspection by an experienced observer. The algorithm can also detect neuronal activity in imaging experiments generated in a different lab using a different microscope configuration (Accuracy = 94.0 % +/2.2). We provide a Google Colaboratory Notebook to allow anyone easy access to this novel tool, for assessment of peripheral neuron activity in their own calcium imaging setups.

neuroscience↗

bioRxiv2022

In vivo calcium imaging shows that satellite glial cells have increased activity in painful states

Satellite glial cells (SGCs) are important for proper neuronal function of primary sensory neurons to whom they provide homeostatic support. Most research of SGC function has been performed with in vitro studies, but recent advances in calcium imaging and transgenic mouse models have enabled this first in vivo study of single cell SGC function in mouse models of inflammation and neuropathic pain. We found that in naive condition SGCs do not respond in a time-locked fashion to neuronal firing. In painful inflammatory and neuropathic states we detected time-locked signals in a subset of SGCs, but only with suprathreshold stimulation of the sciatic nerve. Surprisingly therefore, we conclude that most calcium signals in SGCs seem to develop at arbitrary intervals not directly linked to neuronal activity patterns. More in line with expectations, our experiments also revealed that the number of active SGCs was increased under conditions of inflammation or nerve injury. This could reflect the increased requirement for homeostatic support across dorsal root ganglion neuron populations, which are more active during such painful states.

neuroscience↗