Biology subjects

Fortune, A.

Publications and source records attributed to Fortune, A..

3 recordsLinked to original sources

bioRxiv2024

Low intensity repetitive transcranial magnetic stimulation enhances remyelination by newborn and surviving oligodendrocytes in the cuprizone model of toxic demyelination

In people with multiple sclerosis (MS), newborn and surviving oligodendrocytes (OLs) can contribute to remyelination, however, current therapies are unable to enhance or sustain endogenous repair. Low intensity repetitive transcranial magnetic stimulation (LI-rTMS), delivered as an intermittent theta burst stimulation (iTBS), increases the survival and maturation of newborn OLs in the healthy adult mouse cortex, but it is unclear whether LI-rTMS can promote remyelination. To examine this possibility, we fluorescently labelled oligodendrocyte progenitor cells (OPCs; Pdgfr-CreER transgenic mice) or mature OLs (Plp-CreER transgenic mice) in the adult mouse brain and traced the fate of each cell population over time. Multiple consecutive daily sessions of iTBS (600 pulses; 120 mT), delivered during cuprizone (CPZ) feeding, did not alter new or pre- existing OL survival but increased the number of myelin internodes elaborated by new OLs in the primary motor cortex (M1). This resulted in each new M1 OL producing [~]471{micro}m more myelin. When LI-rTMS was delivered after CPZ withdrawal (during remyelination), it significantly increased the length of the internodes elaborated by new M1 and callosal OLs and increased the number of surviving OLs that contributed to remyelination in the corpus callosum (CC). As LI-rTMS can non-invasively promote remyelination by modifying the behaviour of new and surviving OLs, it may be suitable as an adjunct intervention to enhance remyelination in people with MS.

neuroscience↗

bioRxiv2024

Gluk4-containing kainate receptors regulate synaptic communication in the motor cortex and reduce axon degeneration in adult mice

Glutamate-gated kainate receptors comprising the Gluk4 subunit (encoded by Grik4) are highly expressed by neurons in the central nervous system. We report that Grik4 mRNA is widely expressed by neurons in the adult mouse motor cortex, where GluK4-containing kainate receptors account for [~]60% of the kainate evoked current in layer V pyramidal neurons. To elucidate their role in motor circuit regulation, we analysed the behaviour of mice that lacked the pore forming domain of the GluK4 subunit (Grik4-/-mice). Grik4-/- mice were hyperactive, had an abnormal gait, and impaired motor coordination. At postnatal day (P)60, layer V pyramidal neurons received fewer miniature excitatory post synaptic currents, had a reduced density of thin spines on their basal dendrites, and a reduced density of VGlut1 puncta at the soma, consistent with neurons receiving fewer excitatory synaptic connections. Grik4-/- mice also lost [~]44% of their callosal axons between P60 and P180 and the amplitude of the callosal compound action potential was reduced by [~]25-30%. RNA sequencing data support the capacity for Grik4 to modulate synaptic and neuroprotective signalling pathways.

neuroscience↗

bioRxiv2023

Platelet proteo-transcriptomic profiling validates mediators of thrombosis and proteostasis in patients with myeloproliferative neoplasms

Patients with chronic Myeloproliferative Neoplasms (MPN) including polycythemia vera (PV) and essential thrombocythemia (ET) exhibit unique clinical features, such as a tendency toward thrombosis and hemorrhage, and risk of disease progression to secondary bone marrow fibrosis and/or acute leukemia. Although an increase in blood cell lineage counts (quantitative features) contribute to these morbid sequelae, the significant qualitative abnormalities of myeloid cells that contribute to vascular risk are not well understood. Here, we address this critical knowledge gap via a comprehensive and untargeted profiling of the platelet proteome in a large (n= 140) cohort of patients (from two independent sites) with an established diagnosis of PV and ET (and complement prior work on the MPN platelet transcriptome from a third site). We discover distinct MPN platelet protein expression and confirm key molecular impairments associated with proteostasis and thrombosis mechanisms of potential relevance to MPN pathology. Specifically, we validate expression of high-priority candidate markers from the platelet transcriptome at the platelet proteome (e.g., calreticulin (CALR), Fc gamma receptor (Fc{gamma}RIIA) and galectin-1 (LGALS1) pointing to their likely significance in the proinflammatory, prothrombotic and profibrotic phenotypes in patients with MPN. Together, our proteo-transcriptomic study identifies the peripherally-derived platelet molecular profile as a potential window into MPN pathophysiology and demonstrates the value of integrative multi-omic approaches in gaining a better understanding of the complex molecular dynamics of disease. HighlightsMPN patient platelet proteome identifies key pathobiological mediators of thrombosis and proteostasis. The MPN platelet proteomic profile validates our prior findings from the platelet transcriptome. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/563619v2_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@1cb6290org.highwire.dtl.DTLVardef@1b3ec3eorg.highwire.dtl.DTLVardef@15b0c8eorg.highwire.dtl.DTLVardef@9575b2_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗