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Biology subjects

Gowing, E. K.

Publications and source records attributed to Gowing, E. K..

4 recordsLinked to original sources

MAP1A cleavage regulates TRIM46 transport to the axon in mature neurons

Polarised cargo transport is fundamental to neuronal function, ensuring the proper distribution of proteins and organelles between the cell body and axon. This process is tightly regulated at the proximal axon, where the enrichment of specific proteins organises the local cytoskeleton and directs intracellular trafficking. Although several microtubule-associated proteins (MAPs) have been implicated in axonal cargo transport during neuronal development, how protein localisation is maintained in mature neurons remains poorly understood. Here, we identify a previously unrecognised role for MAP1A in transporting TRIM46, a key organiser of the axonal microtubule cytoskeleton, to the axon of mature neurons, where it supports axon morphology. We show that MAP1A is enriched in the proximal axon and that its cleavage by Calpain-10 into heavy and light chains is required for TRIM46 localisation to this compartment. Mechanistically, the MAP1A light chain interacts with both TRIM46 and the tail domains of KIF3 motors, defining a transport complex that facilitates TRIM46 delivery to the proximal axon. Together, these findings establish proteolytic processing of a microtubule-associated protein as a mechanism regulating axonal protein distribution and neuronal polarity in mature neurons.

neuroscience↗

Comparison of CRISPR-Cas-based knockdown of endogenous mRNA in sensory neurons

RNA-targeting CRISPR-Cas systems enable modulation of gene expression without permanent genome modification, making them useful for sensitive cell types such as neurons. While CRISPR-Cas technologies have been most extensively applied and validated in primary hippocampal and cortical neurons, their use in sensory neurons remains largely unexplored. Sensory neurons are an established cellular model for studying axon growth and regeneration, pain mechanisms, sensory transduction, and neuron-environment interactions. Here, we evaluated the performance of compact RNA-targeting CRISPR-Cas effectors Cas7-11S, hfCas13X, and hfCas13d in primary rat sensory neurons in culture. Using an endogenous mRNA as the target, we compared knockdown efficiency and assessed the effects of CRISPR-Cas expression on neuronal health. The systems showed distinct differences in performance, with Cas7-11S inducing toxicity, hfCas13X showing minimal knockdown, and hfCas13d providing robust gene silencing with minimal adverse effects on neuronal health. These findings identify hfCas13d as an effective and well-tolerated RNA-targeting CRISPR-Cas tool for sensory neurons and provide important insight into its suitability for neuroscience research and potential therapeutic applications.

cell biology↗

GHB confers neuroprotection by stabilizing the CaMKIIα hub domain

Ca2+/calmodulin-dependent protein kinase II alpha (CaMKII) is an abundant neuronal signaling protein involved in synaptic plasticity and memory formation1,2. The central hub domain regulates the activity of CaMKII by organizing the holoenzyme complex into functional oligomers3-6. Recent findings have suggested that the hub is also an allosteric determinant of kinase activity7, and is thus an emerging target for therapies to correct CaMKII dysregulation8,9. However, pharmacological modulation of the hub domain has never been demonstrated. Here we show that stabilization of the CaMKII hub domain confers neuroprotection. By combining photoaffinity labeling and chemical proteomics using small molecule analogs of the natural metabolite {gamma}-hydroxybutyrate (GHB)10 we reveal that CaMKII is the selective target for GHB. We further find that these GHB analogs bind to the hub interior by solving a 2.2 [A] crystal structure of CaMKII with bound ligand. Using differential scanning fluorimetry, we show that binding of ligands to the hub interior increases the thermal stability of hub oligomers in a concentration-dependent manner. Moreover, we demonstrate the functional significance of this hub stabilization by showing substantial neuroprotective effects in cellular excitotoxicity assays and in a mouse model of cerebral ischemia. Together, our results reveal that CaMKII hub stabilization is the mechanism by which GHB provides endogenous neuroprotection and that small-molecule CaMKII-selective ligands have therapeutic potential.

biochemistry↗

The gliopeptide ODN, a ligand for the benzodiazepine site of GABAA receptors, boosts functional recovery after stroke

Following stroke, the survival of neurons and their ability to re-establish connections is critical to functional recovery. This is strongly influenced by the balance between neuronal excitation and inhibition. In the acute phase of experimental stroke, lethal hyperexcitability can be attenuated by positive allosteric modulation of GABAA receptors (GABAAR). Conversely, in the late phase, negative allosteric modulation of GABAAR can correct the sub-optimal excitability and improves both sensory and motor recovery. Here, we hypothesized that octadecaneuropeptide (ODN), an endogenous allosteric modulator of the GABAAR synthesized by astrocytes, influences the outcome of ischemic brain tissue and subsequent functional recovery. We show that ODN boosts the excitability of cortical neurons, which make it deleterious in the acute phase of stroke. However, if delivered after day 3, ODN is safe and improves motor recovery over the following month in two different paradigms of experimental stroke in mice. Furthermore, we bring evidence that during the sub-acute period after stroke, the repairing cortex can be treated with ODN by means of a single hydrogel deposit into the stroke cavity. SIGNIFICANCE STATEMENTStroke remains a devastating clinical challenge because there is no efficient therapy to either minimize neuronal death with neuroprotective drugs or to enhance spontaneous recovery with neurorepair drugs. Around the brain damage, the peri-infarct cortex can be viewed as a reservoir of plasticity. However, the potential of wiring new circuits in these areas is restrained by a chronic excess of GABAergic inhibition. Here we show that an astrocyte-derived peptide (ODN), can be used as a delayed treatment, to safely correct cortical excitability and facilitate sensorimotor recovery after stroke.

neuroscience↗