Functional adaptation of glial cells at neuromuscular junctions in response to injury.

Synaptic elements from neuromuscular junctions (NMJs) undergo massive morphological and functional changes upon nerve injury. While morphological changes of NMJ-associated glia in response to injury has been investigated, their functional properties remain elusive. Perisynaptic Schwann cells (PSCs), glial cells at the NMJ, are essential for NMJ maintenance and repair, and are involved in synaptic efficacy and plasticity. Importantly, these functions are regulated by PSCs ability to detect synaptic transmission through, notably, muscarinic (mAChRs) and purinergic receptors' activation. Using Ca2+ imaging and electrophysiological recordings of synaptic transmission at the mouse NMJ, we investigated PSC receptors activation following denervation and during reinnervation in adults and at denervated NMJs in an ALS mouse model (SOD1G37R ). We observed reduced PSCs mAChR-mediated Ca2+ responses at denervated and reinnervating NMJs. Importantly, PSC phenotypes during denervation and reinnervation were distinct than the one observed during NMJ maturation. At denervated NMJs, exogenous activation of mAChRs greatly diminished galectin-3 expression, a glial marker of phagocytosis. PSCs Ca2+ responses at reinnervating NMJs did not correlate with the number of innervating axons or process extensions. Interestingly, we observed an extended period of reduced PSC mAChRs activation after the injury (up to 60 days), suggesting a glial memory of injury. PSCs associated with denervated NMJs in an ALS model (SOD1G37R mice) did not show any muscarinic adaptation, a phenotype incompatible with NMJ repair. Understanding functional mechanisms that underlie this glial response to injury may contribute to favor complete NMJ and motor recovery.

Management of adverse events related to first-generation tyrosine receptor kinase inhibitors in adults: a narrative review.

OBJECTIVE: The aim of this article is to conduct a literature review on first-generation TRK inhibitors (TRKi), namely entrectinib and larotrectinib, to describe the most common adverse events (AEs) and their management in adults. METHODS: A search strategy was conducted in MEDLINE, EMBASE, and Google Scholar using a list of predetermined keywords. Peer-reviewed articles written in English and published through June 2021 were included. Articles covered included randomized clinical trials and expert recommendations, as well as patent and other types of reviews. RESULTS: The discussed AEs include weight gain and withdrawal pain, as well as neuromuscular, central nervous system (dysesthesias and peripheral sensory neuropathies, dizziness and ataxia, and dysgeusia), gastrointestinal (nausea, vomiting, and diarrhea), and respiratory symptoms. Additionally, several AEs encountered with entrectinib specifically (cognitive and vision disorders, congestive heart failure, QTc elongation, and skeletal fractures) are discussed. First, an overall mechanism of action explaining these AEs is presented. Then, for each AE, incidence and severity are stated and followed by practical management recommendations. While nearly all AEs were reversible upon TRKi suspension, the proposed managements are mainly constituted of pharmacological and non-pharmacological interventions. CONCLUSION: With the estimated growth of gene sequencing in the coming years, it is foreseeable that TRKi will take a larger position in the oncologic therapeutic arsenal. Therefore, adequate management of AEs associated with TRKi in adults should be a prime focus.

COCO/DAND5 inhibits developmental and pathological ocular angiogenesis.

Neovascularization contributes to multiple visual disorders including age-related macular degeneration (AMD) and retinopathy of prematurity. Current therapies for treating ocular angiogenesis are centered on the inhibition of vascular endothelial growth factor (VEGF). While clinically effective, some AMD patients are refractory or develop resistance to anti-VEGF therapies and concerns of increased risks of developing geographic atrophy following long-term treatment have been raised. Identification of alternative pathways to inhibit pathological angiogenesis is thus important. We have identified a novel inhibitor of angiogenesis, COCO, a member of the Cerberus-related DAN protein family. We demonstrate that COCO inhibits sprouting, migration and cellular proliferation of cultured endothelial cells. Intravitreal injections of COCO inhibited retinal vascularization during development and in models of retinopathy of prematurity. COCO equally abrogated angiogenesis in models of choroidal neovascularization. Mechanistically, COCO inhibited TGFß and BMP pathways and altered energy metabolism and redox balance of endothelial cells. Together, these data show that COCO is an inhibitor of retinal and choroidal angiogenesis, possibly representing a therapeutic option for the treatment of neovascular ocular diseases.