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Wonnenberg, P.

Publications and source records attributed to Wonnenberg, P..

3 recordsLinked to original sources

4-methylumbelliferone attenuates amyloid pathology and learning deficits in the APP/PS1 mouse model

4-Methylumbelliferone (4-MU) inhibits hyaluronic acid (HA) synthesis and is currently approved in Europe for biliary spasm. 4-MU administration reduces perineuronal nets (PNNs), and enzymatic degradation of PNNs in mouse models of Alzheimers disease (AD) attenuates memory impairment. Although 4-MU has therapeutic efficacy in rodent models of fibrosis and cancer, it has not been examined in an Alzheimers model. Here, we evaluated the impact of long-term 4-MU treatment in the APP/PS1 amyloid mouse model. From three months of age, mice were on either a vehicle or 4-MU-supplemented diet for 70 days or 52 weeks. Short and long-term 4-MU treatment decreased the soluble parenchymal A{beta}1-42/A{beta}1-40 ratio. Reductions in insoluble amyloid plaque were observed following 52 weeks of treatment. Extended 4-MU administration also reduced PNN intensity and ameliorated spatial memory deficits in APP/PS1 mice. These findings provide support for targeting brain extracellular matrix (ECM) as a therapeutic strategy for AD.

neuroscience↗

Varied monoamine reuptake inhibitors reduce parvalbumin expression; implications for pyramidal cell disinhibition and enhanced neuroplasticity

First-line antidepressants are effective in a significant percent of individuals but a full understanding of how these therapeutics target specific endpoints is lacking. Prior work has shown that depression is associated with hippocampal atrophy and that antidepressants can increase neurotrophin levels to increase hippocampal neurogenesis as well as hippocampal pyramidal cell (PC) spine density and arbor. These effects likely contribute to amelioration of symptoms. A less well-explored possibility is that antidepressants concomitantly disinhibit hippocampal PC activity, which could also facilitate increased PC arbor, spinogenesis and/or activity. In accordance, previous studies have shown antidepressants can attenuate stress-induced upregulation of perineuronal nets (PNNs). PNNs are predominantly localized to parvalbumin (PV) expressing GABAergic interneurons and increase PV expression and neuronal activity. Though specific antidepressants have been explored for effects on regional PNN expression, the question of whether hippocampal PNN/ECM remodeling is a shared feature of varied antidepressant drugs and more importantly, of whether it is associated with significant hippocampal PV inhibition, has not been well-addressed. Herein we examine three monoamine reuptake inhibitors, fluoxetine, venlafaxine and viloxazine, in animal models for effects on PNN remodeling and PV expression, a proxy for PV activity. We observe shared effects of these therapeutics including the ability to increase PNN degrading effectors that can downregulate PV activity. Consistent with this, we observe shared effects of these drugs in terms of their ability to significantly reduce PV levels. These findings highlight the possibility that ECM remodeling and associated hippocampal PC disinhibition represent a shared feature of varied antidepressant medications.

neuroscience↗

An automated two-choice social operant task for probing moment-to-moment changes in social satiety

In naturalistic conditions, animals must routinely make ongoing self-motivated choices about whether to initiate interactions with same or opposite-sex partners and whether to re-initiate social contact when interactions have ended. However, it remains unclear what governs these choices, and whether they are motivated by drive states that exhibit signatures of moment-to-moment social satiety when these interactions have ended. Here, to explicitly test this at the behavioral level, we designed a novel fully-automated two-choice social operant paradigm where individuals can choose between same and opposite-sex social rewards and rewards are delivered for interaction with systematically varying durations. We trained cohorts of both sexes on this task and quantified the patterns of choices. We used choice latency as a metric to infer moment-to-moment satiety to test whether increased interaction duration leads to increased moment-to-moment satiety. We find that although both males and females have stable choice biases across sessions, with males showing consistent opposite sex biases, only males exhibit behavioral signatures of moment-to-moment social satiety and are sensitive to the duration of interaction. Using a simple normative model to capture patterns of social choice, we observe that behavior is better fit by a model that has a single evolving social drive and choice bias, rather than a model with multiple, independent drives for same and opposite-sex interactions. Together, our data reveal behavioral signatures of social satiety and offer new insights into the underlying homeostatic and motivational drives that govern social choices.

neuroscience↗