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Hammond, L. A.

Publications and source records attributed to Hammond, L. A..

2 recordsLinked to original sources

Integrins protect nociceptive neurons in models of paclitaxel-mediated peripheral sensory neuropathy

Chemotherapy induced peripheral neuropathy (CIPN) is a major side effect from cancer treatment with no known method for prevention or cure in clinics. CIPN primarily affects unmyelinated nociceptive sensory terminals. Despite the high prevalence of CIPN, molecular and cellular mechanisms that lead to CIPN are still poorly understood. Here, we used a genetically tractable Drosophila model and primary sensory neurons isolated from adult mouse to examine the mechanisms underlying CIPN and identify protective pathways. We found that chronic treatment of Drosophila larvae with paclitaxel caused sensory neuron degeneration, altered the terminal branching pattern of nociceptive neurons, and reduced thermal nociceptive responses. We found that nociceptive neuron-specific overexpression of integrins, which are known to support neuronal maintenance in several systems, conferred protection from paclitaxel-mediated cellular and behavioral phenotypes. Live imaging and superresolution approaches provide evidence that paclitaxel treatment causes cellular changes that are consistent with alterations in endosome-mediated trafficking of integrins. We used primary dorsal root ganglia neuron cultures to test conservation of integrin-mediated protection. We show that overexpression of a human integrin {beta} subunit 1 (ITGB1) also prevented degeneration following paclitaxel treatment. Altogether, our study supports conserved mechanisms of paclitaxel-induced perturbation of integrin trafficking and a therapeutic potential of restoring integrin levels to antagonize paclitaxel-mediated toxicity in sensory neurons.

neuroscience

An amygdala circuit mediates experience-dependent momentary exploratory arrests

Exploration of novel environments ensures survival and evolutionary fitness. This behavior is expressed through exploratory bouts and arrests, which change dynamically based on experience. Neural circuits mediating exploratory behavior should therefore integrate experience and use it to select the proper behavioral output. Using a spatial exploration assay, we uncovered an experience-dependent increase of momentary arrests in visited locations where animals previously arrested. Quantitative analyses of neuronal calcium activity in freely-exploring mice revealed that a large neuronal ensemble in basolateral amygdala is active during self-paced behavioral arrests. This ensemble was recruited in an experience-dependent manner, and closed-loop optogenetic manipulation of these neurons revealed that they are sufficient and necessary to drive experience-dependent arrests. Additionally, we found that neurons in the basolateral amygdala projecting to central amygdala mediate these momentary arrests. These findings uncover an amygdala circuit that mediates momentary exploratory arrests in familiar places, without changing place preference or anxiety/fear-like behaviors.

neuroscience