Biology subjects

Raveendra, B. L.

Publications and source records attributed to Raveendra, B. L..

3 recordsLinked to original sources

bioRxiv2024

PKA Activity-Driven Modulation of Bidirectional Long-Distance transport of Lysosomal vesicles During Synapse Maintenance

The bidirectional long-distance transport of organelles is crucial for cell body-synapse communication. However, the mechanisms by which this transport is modulated for synapse formation, maintenance, and plasticity are not fully understood. Here, we demonstrate through quantitative analyses that maintaining sensory neuron-motor neuron synapses in the Aplysia gill-siphon withdrawal reflex is linked to a sustained reduction in the retrograde transport of lysosomal vesicles in sensory neurons. Interestingly, while mitochondrial transport in the anterograde direction increases within 12 hours of synapse formation, the reduction in lysosomal vesicle retrograde transport appears three days after synapse formation. Moreover, we find that formation of new synapses during learning induced by neuromodulatory neurotransmitter serotonin further reduces lysosomal vesicle transport within 24 hours, whereas mitochondrial transport increases in the anterograde direction within one hour of exposure. Pharmacological inhibition of several signaling pathways pinpoints PKA as a key regulator of retrograde transport of lysosomal vesicles during synapse maintenance. These results demonstrate that synapse formation leads to organelle-specific and direction specific enduring changes in long-distance transport, offering insights into the mechanisms underlying synapse maintenance and plasticity.

neuroscience↗

bioRxiv2024

lncRNA ADEPTR loss-of-function elicits sex-specific behavioral and spine deficits

Activity-dependent changes in neuronal connections are fundamental to learning and long-term memory storage. However, the precise contribution of long noncoding RNAs (lncRNAs) to these modifications remains unclear. In this study, we assessed the role of the lncRNA ADEPTR, a cAMP-modulated lncRNA localized in dendrites, which is crucial for synapse morphology. By generating two different mouse models--one with a deletion of ADEPTR (L-ADEPTR) and one with a deletion of its protein interaction region (S-ADEPTR)--we investigated the sex-specific impacts of ADEPTR loss of function on learning, memory, dendritic arborization, and synapse morphology. Our behavioral analyses revealed a reduction in anxiety in adult male mice, while learning and memory remained unaffected in both models. Systematic evaluations of neuronal morphology across various developmental stages ([~]3-day-old postnatal neuronal cultures and postnatal 14- and 42-day-old male and female mice) uncovered substantial deficits in neuronal architecture in both S- and L-ADEPTR male and female neuronal cultures. At postnatal day 42, in contrast to their male counterparts, L-ADEPTR female mice exhibited a significant deficiency in thin spines. Additionally, we found that the expression of plasticity-related gene BDNF, and immediate early gene cFOS were enhanced in both the cortex and hippocampus of adult male and female S- and L-ADEPTR mice, suggesting the activation of a compensatory mechanism protecting against learning and memory deficits. Collectively, these observations underscore the sex-specific role of lncRNA ADEPTR in shaping neuronal morphology and anxiety behavior.

neuroscience↗

bioRxiv2023

Single neuron analysis of aging associated changes in learning reveals progressive impairmentsin transcriptional plasticity

Molecular mechanisms underlying aging associated impairments in learning and long-term memory storage are poorly understood. Here we leveraged the single identified motor neuron L7 in Aplysia, which mediates a form of non-associative learning, sensitization of the siphon-withdraw reflex, to assess the transcriptomic correlates of aging associated changes in learning. RNAseq analysis of the single L7 motor neuron isolated following short-term or long-term sensitization training of 8,10 and 12 months old Aplysia, corresponding to mature, late mature and senescent stages, has revealed progressive impairments in transcriptional plasticity during aging. Specifically, we observed modulation of the expression of multiple lncRNAs and mRNAs encoding transcription factors, regulators of translation, RNA methylation, and cytoskeletal rearrangements during learning and their deficits during aging. Our comparative gene expression analysis also revealed the recruitment of specific transcriptional changes in two other neurons, the motor neuron L11 and the giant cholinergic neuron R2 whose roles in long-term sensitization were previously not known. Taken together, our analyses establish cell type specific progressive impairments in the expression of learning- and memory-related components of the transcriptome during aging.

neuroscience↗