Unraveling the Mechanistic Circuits Driving Spontaneous Neuropathic Pain

Authors:

Elke Bentley, Xiangsunze Zeng, Clifford Woolf

Date Created:

2025-01-01

Course Title:

Professor:

Not specified

About Paper:

Spontaneous neuropathic pain arises from damage or dysfunction spontaneousneuropathicpaininthechronicphase. InvivoGCaMP in the nervous system and occurs without any external trigger. calcium imaging identified a causal relationship between small- While opioids are commonly used to manage this condition, diameter DRG neuron subtypes and neuropathic pain within the they act broadly across multiple cell types, including both those neuroma. Through in vivo optogenetic studies, we were able to associated with pain and those associated with addiction. Our reinforcethiscausalrelationshipbytriggeringthesespecificsmall- objective is to identify the specific dorsal root ganglion (DRG) diameter DRG neuron subtypes to cause spontaneous neuropathic cell type responsible for spontaneous neuropathic pain, enabling pain behavior (i.e. flicking). Single-nucleus RNA sequencing the development of targeted, non-addictive therapies. on DRG tissue and ex vivo immunohistochemistry on neuroma and DRG samples, revealed the specific sensory neurons and ion To model this condition, we employed a sciatic nerve transection channelsthatcausethehyperexcitabilitywithinneuronsthatleadto (SNT) in mice to induce a neuroma, an aberrant fibrous mass high levels of pain. We are looking forward to a potential clinical formed by disorganized nerve regeneration known to drive chronic pain. Continuous 24-hour recordings using wireless EMG study to create and test a treatment method targeting specifically transmitters revealed flicking behavior as a reliable marker of this small-diameter DRG neuron subtype to combat spontaneous neuropathic pain in humans. Tunable Alginate and Decellularized Extracellular Matrix Injectable Hydrogels for Tendon Healing Hari Bezwada, Grace Atteh, Benjamin Freedman Harvard College | Quincy House | Human Developmental and Regenerative Biology | 2028 The inherent low vascularization of tendon leads to prolonged five different testing groups: (1) pure high molecular weight healing times and inadequate regenerative capacity, highlighting alginate, (2) pure low molecular weight alginate, (3) hybrid dECM the need for localized, regenerative therapies. Hydrogels are + high molecular weight alginate gel, (4) hybrid dECM + low particularly promising as non-invasive, biocompatible options to molecularweightalginategel,and(5)puredECMgel. Rheological treat tendon-related disorders. Hydrogel scaffolds can harbor testing assessed modulus values for each group via oscillation and tissue-specific cell lines to enhance cell therapies. Stiffness andstress relaxation. To evaluate cell morphology, the dECM, cell viscoelasticity of cell environments has been found to affect suspension, and crosslinker mixtures were mixed via syringe and cell morphology, migration, and proliferation. However, the injected into a 1.5 mm glass mold for crosslinking. The tendon- impact of tuning these properties in hydrogels incorporating derived primary cells were cultured in the gel mixture for 3 days, tendon-derived decellularized extracellular matrix (dECM) is not then cryosectioned, stained with DAPI and Phalloidin, and imaged well explored. This study aimed at developing a 3D tendon under a fluorescence microscope. The immunofluorescence niche using a dual network alginate-dECM injectable hydrogel images will give some insight into the correlation between the for tendon healing. We hypothesized that incorporating dECM viscoelastic properties of the material and the behavior of the cells and modulating the viscoelasticity of alginate using varying in this environment compared to their native environment based on combinations of crosslinker to polymer content would allow for cellular morphology and phenotype, suggesting this to be a good better mimicry of the native tendon environment and therefore in-vitro model to study tendon-related disorders. promote favorable cell responses. Our study design consists of A High-Precision, Low-Turbulence Vertical Wind Tunnel for Microrobotic- Insect Flight Testing Arav Bhargava, Elio Challita, Rob Wood Harvard College | Cabot House | Mechanical Engineering | 2028 Vertical wind tunnels allow for the controlled study of at the tunnel walls, two straight sections, two honeycomb stages gliding flight. They are particularly valuable for investigating (64 mm and 40 mm tall), four 34-mesh screens at specific axial aerodynamic phenomena, such as flapping, maneuvering, and positions,andahot-wiresensormount. A335KVbrushlessmotor, stability control, in both microrobotic platforms and biological driving an 8 ▯ 6 three-blade propeller, is governed by an ESC and insects. However, no small-scale vertical wind tunnel exists calibrated by an Arduino-based PID loop that reads a FS3000 hot- that can reproduce the laminar flow conditions (Re < 2300) wire sensor, adjusting the set air velocity in real-time. Our initial characteristic of micro-scale systems. This work, therefore, aims tests use a 10 mW laser to generate a thin laser sheet for planar to develop a low-cost, compact vertical wind tunnel capable of flow visualization. Glycerol particles are seeded into the fluid and generatinguniformlaminarflowatReynoldsnumbersbelow2300. carried around a test cylinder, where their motion is recorded to In this study, we introduce a high-precision, compact, low-cost, reveal the flow patterns and potential wake structures. Particle and fully open-source vertical wind tunnel that can be replicated Image Velocimetry (PIV) of the glycerol-seeded flow illuminated in less than 2 days of fabrication and construction time. Our wind by the laser sheet confirms a uniformly low-turbulence, laminar tunnel delivers 0.3-2.5 m/s airflow with ▯0:02 m/s resolution profile. While precise quantification of the Reynolds number has and low turbulence in a sub-600 mm tall, $150 budget design. Our yet to be identified, the observed flow behavior is consistent with constructionreliesonFDM3D-printedmodularcomponents,a220 Re < 80. mm-diameterbase, twocontractionnozzlestoeliminateturbulence 90 Program for Research in Science and Engineering DecodingAntigen-SpecificToleranceMechanismsImposedbyanMHCClass

Abstract:

Spontaneous neuropathic pain arises from damage or dysfunction spontaneousneuropathicpaininthechronicphase. InvivoGCaMP in the nervous system and occurs without any external trigger. calcium imaging identified a causal relationship between small- While opioids are commonly used to manage this condition, diameter DRG neuron subtypes and neuropathic pain within the they act broadly across multiple cell types, including both those neuroma. Through in vivo optogenetic studies, we were able to associated with pain and those associated with addiction. Our reinforcethiscausalrelationshipbytriggeringthesespecificsmall- objective is to identify the specific dorsal root ganglion (DRG) diameter DRG neuron subtypes to cause spontaneous neuropathic cell type responsible for spontaneous neuropathic pain, enabling pain behavior (i.e. flicking). Single-nucleus RNA sequencing the development of targeted, non-addictive therapies. on DRG tissue and ex vivo immunohistochemistry on neuroma and DRG samples, revealed the specific sensory neurons and ion To model this condition, we employed a sciatic nerve transection channelsthatcausethehyperexcitabilitywithinneuronsthatleadto (SNT) in mice to induce a neuroma, an aberrant fibrous mass high levels of pain. We are looking forward to a potential clinical formed by disorganized nerve regeneration known to drive chronic pain. Continuous 24-hour recordings using wireless EMG study to create and test a treatment method targeting specifically transmitters revealed flicking behavior as a reliable marker of this small-diameter DRG neuron subtype to combat spontaneous neuropathic pain in humans. Tunable Alginate and Decellularized Extracellular Matrix Injectable Hydrogels for Tendon Healing Hari Bezwada, Grace Atteh, Benjamin Freedman Harvard College | Quincy House | Human Developmental and Regenerative Biology | 2028 The inherent low vascularization of tendon leads to prolonged five different testing groups: (1) pure high molecular weight healing times and inadequate regenerative capacity, highlighting alginate, (2) pure low molecular weight alginate, (3) hybrid dECM the need for localized, regenerative therapies. Hydrogels are + high molecular weight alginate gel, (4) hybrid dECM + low particularly promising as non-invasive, biocompatible options to molecularweightalginategel,and(5)puredECMgel. Rheological treat tendon-related disorders. Hydrogel scaffolds can harbor testing assessed modulus values for each group via oscillation and tissue-specific cell lines to enhance cell therapies. Stiffness andstress relaxation. To evaluate cell morphology, the dECM, cell viscoelasticity of cell environments has been found to affect suspension, and crosslinker mixtures were mixed via syringe and cell morphology, migration, and proliferation. However, the injected into a 1.5 mm glass mold for crosslinking. The tendon- impact of tuning these properties in hydrogels incorporating derived primary cells were cultured in the gel mixture for 3 days, tendon-derived decellularized extracellular matrix (dECM) is not then cryosectioned, stained with DAPI and Phalloidin, and imaged well explored. This study aimed at developing a 3D tendon under a fluorescence microscope. The immunofluorescence niche using a dual network alginate-dECM injectable hydrogel images will give some insight into the correlation between the for tendon healing. We hypothesized that incorporating dECM viscoelastic properties of the material and the behavior of the cells and modulating the viscoelasticity of alginate using varying in this environment compared to their native environment based on combinations of crosslinker to polymer content would allow for cellular morphology and phenotype, suggesting this to be a good better mimicry of the native tendon environment and therefore in-vitro model to study tendon-related disorders. promote favorable cell responses. Our study design consists of A High-Precision, Low-Turbulence Vertical Wind Tunnel for Microrobotic- Insect Flight Testing Arav Bhargava, Elio Challita, Rob Wood Harvard College | Cabot House | Mechanical Engineering | 2028 Vertical wind tunnels allow for the controlled study of at the tunnel walls, two straight sections, two honeycomb stages gliding flight. They are particularly valuable for investigating (64 mm and 40 mm tall), four 34-mesh screens at specific axial aerodynamic phenomena, such as flapping, maneuvering, and positions,andahot-wiresensormount. A335KVbrushlessmotor, stability control, in both microrobotic platforms and biological driving an 8 ▯ 6 three-blade propeller, is governed by an ESC and insects. However, no small-scale vertical wind tunnel exists calibrated by an Arduino-based PID loop that reads a FS3000 hot- that can reproduce the laminar flow conditions (Re < 2300) wire sensor, adjusting the set air velocity in real-time. Our initial characteristic of micro-scale systems. This work, therefore, aims tests use a 10 mW laser to generate a thin laser sheet for planar to develop a low-cost, compact vertical wind tunnel capable of flow visualization. Glycerol particles are seeded into the fluid and generatinguniformlaminarflowatReynoldsnumbersbelow2300. carried around a test cylinder, where their motion is recorded to In this study, we introduce a high-precision, compact, low-cost, reveal the flow patterns and potential wake structures. Particle and fully open-source vertical wind tunnel that can be replicated Image Velocimetry (PIV) of the glycerol-seeded flow illuminated in less than 2 days of fabrication and construction time. Our wind by the laser sheet confirms a uniformly low-turbulence, laminar tunnel delivers 0.3-2.5 m/s airflow with ▯0:02 m/s resolution profile. While precise quantification of the Reynolds number has and low turbulence in a sub-600 mm tall, $150 budget design. Our yet to be identified, the observed flow behavior is consistent with constructionreliesonFDM3D-printedmodularcomponents,a220 Re < 80. mm-diameterbase, twocontractionnozzlestoeliminateturbulence 90 Program for Research in Science and Engineering DecodingAntigen-SpecificToleranceMechanismsImposedbyanMHCClass

Source:

Harvard / Parnitha Bandla, Celeste Wu, Jessica Whited / 2025

Topics:

cell, pain, tendon, low, tunnel, neuropathic, drg, alginate, wind, spontaneou, high, hydrogel

Co-authors:

@elkebentley252 , @xiangsunzezeng253 , @cliffordwoolf254