MBE702 Seminar Evaluation: Nicholas Kron
The Stages of Aging: Differential Expression Time Series of Aplysia californica Sensory Neurons
Nicholas S. Kron
The marine model Aplysia californica (Aplysia) ranks among the most widely used organisms in neuroscience, primarily due to its ability to learn using simple neural circuits. Previously, the transcriptional profiles of sexually mature and aged Aplysia were investigated to determine transcriptional correlates of aging via RNA sequencing (RNAseq; Greer et al 2018). In this expanded study, cDNA from sensory neurons of 76 animals spanning 7 time points (6 months to 12 months), four Aplysia Stages of Aging (juvenile, mature, Aged I, and Aged II) and two identified neuronal clusters (pleural ventral caudal neurons of the pleural ganglia and buccal S cluster neurons of the buccal ganglia) was sequenced on an Illumina HiSeq2500 sequencer for 100 base pair, paired-end sequences.
Differential expression analysis identified 297 significantly differentially expressed (DE) transcripts (p0.05). Gene ontology annotation of DE transcript revealed significant enrichment (p<0.05) for several categories including divalent inorganic cation homeostasis (GO:0072507) and cellular metal ion homeostasis (GO:0006875), indicating these processes may mediate physiological changes associated with age in Aplysia sensory neurons observed previously. Finally, clustering of the expression profiles of these DE transcripts yielded 8 common transcriptional trajectories with age, revealing the complex activity of several genes that may underlie the aging process.