Emma Theisen

All Publications

• From seconds to days: Neural plasticity viewed through a lipid lens. Current opinion in neurobiology Vaughen, J. P., Theisen, E., Clandinin, T. R. 2023; 80: 102702

  Abstract

  Many adult neurons are dynamically remodeled across timescales ranging from the rapid addition and removal of specific synaptic connections, to largescale structural plasticity events that reconfigure circuits over hours, days, and months. Membrane lipids, including brain-enriched sphingolipids, play crucial roles in these processes. In this review, we summarize progress at the intersection of neuronal activity, lipids, and structural remodeling. We highlight how brain activity modulates lipid metabolism to enable adaptive structural plasticity, and showcase glia as key players in membrane remodeling. These studies reveal that lipids act as critical signaling molecules that instruct the dynamic architecture of the brain.

  View details for DOI 10.1016/j.conb.2023.102702

  View details for PubMedID 36965206

• Glial control of sphingolipid levels sculpts diurnal remodeling in a circadian circuit. Neuron Vaughen, J. P., Theisen, E., Rivas-Serna, I. M., Berger, A. B., Kalakuntla, P., Anreiter, I., Mazurak, V. C., Rodriguez, T. P., Mast, J. D., Hartl, T., Perlstein, E. O., Reimer, R. J., Clandinin, M. T., Clandinin, T. R. 2022

  Abstract

  Structural plasticity in the brain often necessitates dramatic remodeling of neuronal processes, with attendant reorganization of the cytoskeleton and membranes. Although cytoskeletal restructuring has been studied extensively, how lipids might orchestrate structural plasticity remains unclear. We show that specific glial cells in Drosophila produce glucocerebrosidase (GBA) to locally catabolize sphingolipids. Sphingolipid accumulation drives lysosomal dysfunction, causing gba1b mutants to harbor protein aggregates that cycle across circadian time and are regulated by neural activity, the circadian clock, and sleep. Although the vast majority of membrane lipids are stable across the day, a specific subset that is highly enriched in sphingolipids cycles daily in a gba1b-dependent fashion. Remarkably, both sphingolipid biosynthesis and degradation are required for the diurnal remodeling of circadian clock neurites, which grow and shrink across the day. Thus, dynamic sphingolipid regulation by glia enables diurnal circuit remodeling and proper circadian behavior.

  View details for DOI 10.1016/j.neuron.2022.07.016

  View details for PubMedID 35961319

• Adverse caregiving in infancy blunts neural processing of the mother NATURE COMMUNICATIONS Opendak, M., Theisen, E., Blomkvist, A., Hollis, K., Lind, T., Sarro, E., Lundstrom, J. N., Tottenham, N., Dozier, M., Wilson, D. A., Sullivan, R. M. 2020; 11 (1): 1119

  Abstract

  The roots of psychopathology frequently take shape during infancy in the context of parent-infant interactions and adversity. Yet, neurobiological mechanisms linking these processes during infancy remain elusive. Here, using responses to attachment figures among infants who experienced adversity as a benchmark, we assessed rat pup cortical local field potentials (LFPs) and behaviors exposed to adversity in response to maternal rough and nurturing handling by examining its impact on pup separation-reunion with the mother. We show that during adversity, pup cortical LFP dynamic range decreased during nurturing maternal behaviors, but was minimally impacted by rough handling. During reunion, adversity-experiencing pups showed aberrant interactions with mother and blunted cortical LFP. Blocking pup stress hormone during either adversity or reunion restored typical behavior, LFP power, and cross-frequency coupling. This translational approach suggests adversity-rearing produces a stress-induced aberrant neurobehavioral processing of the mother, which can be used as an early biomarker of later-life pathology.

  View details for DOI 10.1038/s41467-020-14801-3

  View details for Web of Science ID 000518626300012

  View details for PubMedID 32111822

  View details for PubMedCentralID PMC7048726

• Control of Synaptic Specificity by Establishing a Relative Preference for Synaptic Partners NEURON Xu, C., Theisen, E., Maloney, R., Peng, J., Santiago, I., Yapp, C., Werkhoven, Z., Rumbaut, E., Shum, B., Tamogorska, D., Borycz, J., Tan, L., Courgeon, M., Meinertzhagen, I. A., de Bivort, B., Drugowitsch, J., Pecot, M. Y. 2019; 103 (5): 865-+

  Abstract

  The ability of neurons to identify correct synaptic partners is fundamental to the proper assembly and function of neural circuits. Relative to other steps in circuit formation such as axon guidance, our knowledge of how synaptic partner selection is regulated is severely limited. Drosophila Dpr and DIP immunoglobulin superfamily (IgSF) cell-surface proteins bind heterophilically and are expressed in a complementary manner between synaptic partners in the visual system. Here, we show that in the lamina, DIP mis-expression is sufficient to promote synapse formation with Dpr-expressing neurons and that disrupting DIP function results in ectopic synapse formation. These findings indicate that DIP proteins promote synapses to form between specific cell types and that in their absence, neurons synapse with alternative partners. We propose that neurons have the capacity to synapse with a broad range of cell types and that synaptic specificity is achieved by establishing a preference for specific partners.

  View details for DOI 10.1016/j.neuron.2019.06.006

  View details for Web of Science ID 000484400200013

  View details for PubMedID 31300277

  View details for PubMedCentralID PMC6728174