DLK-gated responses in motoneurons following sciatic nerve crush
Ontology highlight
ABSTRACT: To profile downstream gene-expression changes regulated by DLK, we profiled motoneurons in the lumbar spinal cord using RiboTag, following sciatic nerve crush in both control and Dlk conditional knockout (Dlk ΔMN) mice. We found that DLK regulates the expression of many secreted proteins, which have the potential to influence the behavior of other cells, including the immune system.
Project description:RNA was purified from retinas following crush in the presence of vehicle or DLKi The "SAMPLE_ID" sample characteristic is a sample identifier internal to Genentech. The ID of this project in Genentech's ExpressionPlot database is PRJ0010360
Project description:The conserved MAPKKK DLK plays many roles in neuronal development, axon injury, and neuronal stress responses. The outcomes of activating or inhibiting DLK signaling depend on cell-type and cellular contexts. Emerging evidence has implicated DLK signaling in several neurodegenerative diseases. However, our understanding of the DLK-dependent cellular network in the central nervous system remains limited. Here, we investigated roles of DLK in hippocampal glutamatergic neurons, using conditional knockout and overexpression mice. We find that dorsal CA1 and dentate gyrus neurons are particularly vulnerable to elevated DLK activity. We performed RiboTRAP-seq analysis and identified the DLK dependent translatome, majority of which are involved in neuronal developmental processes, neuronal stress responses, and synapse formation and function. Increasing DLK signaling is associated with disruptions of microtubules, potentially involving Stmn4. We also show that in primary hippocampal neurons DLK regulates neurite outgrowth, axon specification, and synapse formation. This study broadens our understanding of both conserved and cell-type specific effects of DLK signaling. The identification of translational targets of DLK in glutamatergic neurons has relevance to our understanding of neurodegenerative disease.
Project description:We report RNA sequencing data from induced Schwann cell specific knockouts for DICER and DGCR8 as well as crush injured wild type animals. Induced deletion of DICER and DGCR8 results in expression of numerous injury response genes suggesting a requirement of those proteins in maintaining the myelinated Schwann cell fate.
Project description:Dual Leucine-zipper Kinase (DLK)-dependent stress signaling is a critical determinant of neuronal survival and regenerative potential following axon damage, but it remains uncertain whether injury-activated DLK is adequate to initiate and maintain a pro-regenerative transcriptional response in the CNS. Using a drug-activatable DLK construct, we stimulated stress signaling for comparison of the retinal transcriptional response to, and in addition to, the response stimulated by mouse optic nerve injury in wildtype mice and in the context of partial axon regeneration enabled by disruption of the tumor suppressor PTEN.
Project description:Three cell types, intermediolateral column motoneurons, medial motoneurons, and lateral motoneurons were isolated from a single adult spinal cord using laser capture microscopy. Four hundred captures were collected for each cell type. For a given cell type, RNA was extracted from the 400 captures using an Arcturus picopure kit. RNA was split in half and two targets were produced using a double amplification protocol. Each target was hybridized to Affymetrix chips and signals were normalized with R-pack. Inverse logs are provided. Five animals were used in these experiments, and all three cell types were collected from each animal. Thus, for each cell type, there are five biological replicates, and for each biological replicate there are two technical replicates. In all thirty chips were analyzed. Techinical replicates are indicated as Set 1 and Set 2. Animal numbers are indicated by Pair1 through Pair 5. Keywords: other
Project description:Injury to peripheral axons initiates a complex cascade of cellular responses, including cytoskeletal disassembly, axon transport disruption, and ultimately axon regeneration. Central to this process is the MAP triple kinase Dual-Leucine Zipper Kinase (DLK), activated by injury and other neuronal stressors. Here, we propose the existence of a homeostatic mechanism termed the Cytoskeletal Perturbation Response (CPR). We investigate this hypothesis by examining the response of cultured dorsal root ganglion (DRG) neurons to low dose nocodazole treatment, a cytoskeletal perturbing agent. To gain insights into DLK-dependent transcriptional changes following cytoskeletal insult, we performed bulk RNA sequencing on cultured neurons treated for 16 hours. Using a fully crossed two-factor design, we determined the interactive effect of DLK on nocodazole- dependent transcriptional changes. Our study demonstrates that cytoskeletal perturbation triggers DLK-dependent signaling cascades, leading to significant transcriptional changes. These changes involve transcription factors (Jun, Egr1, Atf3) and MAP kinase regulators (DUSPs), pointing to a regulatory network that attenuates DLK signaling. Taken together, our findings suggest that cytoskeletal perturbation activates a DLK-dependent homeostatic mechanism, the CPR, which orchestrates transcriptional changes and morphological adaptations to repair neuronal damage. The CPR bears similarities to established homeostatic responses, offering insights into the intricate processes that underlie axon regeneration and cellular repair.
Project description:We used two groups of C57BL/6J mice, one with optic nerve crush on one eye, and another with no crush as control. Three mice were subjected to optic nerve crush, with sample names 121, 113, 114 and two were used as control with sample names 118 and 119. For the optic nerve crush, a surgical peritomy was made behind and above the eyeball and the eye muscles were gently retracted to expose the optic nerve. Dumont #5 forceps (FST) were used to crush the optic nerve approximately 0.5-1 mm behind the globe without damaging retinal vessels or affecting the blood supply.