Macrophages protect against sensory axon degeneration in diabetic neuropathy
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1075431 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Diabetic peripheral neuropathy (DPN) is a common complication of diabetes, causing sensory loss and debilitating neuropathic pain1,2. Although the onset and progression of DPN have been linked with dyslipidemia and hyperglycemia3, the contribution of inflammation in the pathogenesis of DPN has not been investigated. Here, we use a High Fat High Fructose Diet (HFHFD) to model DPN and its metabolic syndrome in mice. Diabetic mice develop persistent heat hypoalgesia after three months, but a reduction in epidermal skin innervation only manifests at 6 months. Using single-cell sequencing, we find that CCR2+ macrophages infiltrate the sciatic nerves of diabetic mice well before axonal degeneration is detectable. We show that these infiltrating macrophages share gene expression similarities with nerve crush-induced macrophages4 and express neurodegeneration-associated microglia marker genes5 although there is no axon loss or demyelination yet. Inhibiting this macrophage recruitment in diabetic mice by genetically or pharmacologically blocking CCR2 signaling results in a more severe heat hypoalgesia and accelerated skin denervation. These findings reveal a novel neuroprotective recruitment of macrophages into peripheral nerves of diabetic mice that delays the onset of terminal axonal degeneration, thereby reducing sensory loss. Potentiating and sustaining this early neuroprotective immune response in patients represents, therefore, a potential means to reduce or prevent DPN.
2024-12-03 | GSE255553 | GEO
Project description:Axon degeneration sculpts precise patterns of connectivity in the developing nervous system and is an early pathological hallmark of several adult-onset neurodegenerative disorders. Substantial progress has been made in identifying effector mechanisms that drive axon fragmentation, but far less is known about the upstream signaling pathways that initiate this process. Here we describe a role for the newly discovered axonal Membrane-associated Periodic Skeleton (MPS) –a quasi-1D periodic ultrastructure composed of actin, spectrin and associated molecules– during sensory axon degeneration. We find that trophic deprivation (TD) of sensory axons causes a rapid breakdown in the periodicity of the MPS in distal axons. These structural changes occur prior to and independently of caspase-driven axon fragmentation. We further show that acute actin destabilization to break down the MPS can initiate TD-related retrograde signaling. Actin stabilization prevents MPS breakdown during TD and blocks this signal. Moreover, deletion of βII-spectrin (Sptbn1), an obligate component of the MPS, suppresses this retrograde signaling and protects axons against degeneration. Together our data suggest that ultrastructural plasticity of the MPS underlies the earliest steps of axon degeneration.
2019-03-14 | PXD009854 | Pride
Project description:Axon loss contributes to many common neurodegenerative disorders. In healthy axons, the axon survival factor NMNAT2 inhibits SARM1, the central executioner of programmed axon degeneration. We identified two rare NMNAT2 missense variants in two brothers afflicted with a progressive neuropathy syndrome. The polymorphisms result in amino acid substitutions, V98M and R232Q, which reduce NMNAT2 NAD+-synthetase activity. We generated a mouse model of the human syndrome and found that Nmnat2V98M/Nmnat2R232Q compound-heterozygous CRISPR mice survive to adulthood but develop progressive motor dysfunction, peripheral axon loss, and macrophage infiltration. These disease phenotypes are all SARM1-dependent. Remarkably, macrophage depletion therapy blocks and reverses neuropathic phenotypes in Nmnat2V98M/R232Q mice, identifying a SARM1-dependent neuroimmune mechanism as a key driver of disease pathogenesis. These findings demonstrate that SARM1 induces an inflammatory neuropathy and highlight the potential of immune therapy to treat this rare syndrome and other neurodegenerative conditions associated with NMNAT2 loss and SARM1 activation.
2022-10-25 | GSE210403 | GEO
Project description:HO1 activates autophagy to protect intervertebral disc degeneration
| PRJNA450426 | ENA
Project description:Axon degeneration and neurological dysfunction in myelin diseases is often attributed to loss of myelin. Perturbed myelinating glia can instigate chronic neuroinflammation and contribute to demyelination and axonal damage. We have previously shown in mice that distinct defects in the proteolipid protein 1 gene result in axonal damage which is largely driven by cytotoxic T cells targeting myelinating oligodendrocytes. Here we show in these mutants that persistent ensheathment with perturbed myelin poses a risk for axon degeneration, neuron loss, and behavioral decline. We demonstrate that CD8+ T cell-driven axonal damage is less likely to progress towards degeneration when axons are efficiently demyelinated by activated microglia. Mechanistically, we show that cytotoxic T cell effector molecules induce aberrant cytoskeletal plasticity within myelinating glial processes and constriction of axons at paranodal domains. Our study identifies detrimental axon-glia interactions which promote neurodegeneration and possible therapeutic targets for disorders associated with myelin defects and neuroinflammation.
2023-09-29 | GSE224032 | GEO
Project description:Canine cerebrum RNAseq, Border Collie Breed, sensory neuropathy case
| PRJEB12352 | ENA
Project description:Rac1, a member of the small G protein Rho family, has been implicated in neurodegenerative diseases. However, its role in axon degeneration is not fully understood. Here we found that activation of Rac1 exacerbated axonal transport damage in an experimental glaucoma model. Inhibiting Rac1 activity by genetic or pharmacological methods alleviated the dysfunction of axonal transport and improved the integrity of microtubule by upregulating the expression of β-III tubulin and myelin basic protein. Rac1 interacted with Sirt1, a key molecule of Wallerian degeneration, which regulated the activity of PAK1, a downstream molecule of Rac1. Furthermore, Rac1 modulated Kif motors at the transcriptional level, among which Kif2a, a lysosome-location regulator, was negatively regulated by Rac1. Intravitreal injection of Kif2a siRNA reversed the improvement of Rac1 inhibition-mediated axonal transport through reducing autophagolysosomes. Our results suggest that Rac1/Kif2a accelerates the process of RGC axon degeneration by impairing the autophagic flux in glaucoma, which may be an intriguing therapy target for glaucoma.
2024-12-01 | GSE247696 | GEO
Project description:Glia assess axon structure to modulate myelination and axon repair. Whether glia similarly detect dendrites and their substructures is not well understood. Here, we show that glia monitor the integrity of dendrite substructures and transiently protect their perturbation. We demonstrate that disruption of C. elegans sensory neuron dendrite cilia elicits acute glial responses, including increased accumulation of glia-derived extracellular matrix around cilia, changes in gene expression, and alteration of secreted protein repertoire. DGS-1, a 7-transmembrane domain neuronal protein, and FIG-1, a multifunctional thrombospondin-domain glial protein, are required for glial detection of cilia integrity, physically interact, and exhibit mutually-dependent localization to and around cilia, respectively. Glial responses to dendrite cilia disruption transiently protect against damage. Thus, our studies uncover a homeostatic, protective, dendrite glia signaling interaction regulating dendrite substructure integrity.
2024-12-06 | GSE282640 | GEO
Project description:Drosophila mushroom body (MB) γ neurons undergo axon pruning during metamorphosis through a process of localized degeneration of specific axon branches. Developmental axon degeneration is initiated at the onset of metamorphosis by the pre-pupal rise in the steroid hormone ecdysone. This study identifies genes that alter their expression in MB neurons at the onset and early steps of axon pruning. Keywords: timecourse
2008-06-01 | GSE10012 | GEO
Project description:The neuromuscular junction (NMJ) is a specialized tripartite synapse composed of the motor axon terminal, covered by perisynaptic Schwann cells (PSCs), and the muscle fibre, separated by a basal lamina. It is exposed to different kind of injures such as mechanical traumas, pathogens including neurotoxins, and neuromuscular diseases such as amyotrophic lateral sclerosis and immune-mediated disorders, and has retained throughout vertebrate evolution an intrinsic ability for repair and regeneration, at variance from central synapses1. Following peripheral nerve injury, an intense but poorly defined crosstalk takes place at the NMJ among its components, functional to nerve terminal regeneration. To identify crucial factors released by PSCs and the muscle to induce nerve regrowth, we performed a transcriptome analysis of the NMJ at different time points after injection of -latrotoxin, a presynaptic neurotoxin isolated from the venom of the black widow spider. This toxin is a simple and controlled method to induce an acute, localized and reversible nerve terminal degeneration not blurred by inflammation, and can help to identify molecules involved in the intra- and inter-cellular signalling governing NMJ regeneration.
2017-05-30 | E-MTAB-5730 | biostudies-arrayexpress