Synaptic function is reflected in quantifiable ultrastructural features using electron microscopy (EM) approaches. This coupling of synaptic function and ultrastructure suggests that in vivo synaptic function can be inferred from EM analysis of ex vivo human brain tissue. To investigate this, we employed focused ion beam-scanning electron microscopy (FIB-SEM), a volume EM (VEM) approach, to generate ultrafine-resolution, three-dimensional (3D) micrographic datasets of postmortem human dorsolateral prefrontal cortex (DLPFC), a region with cytoarchitectonic characteristics distinct to human brain. Synaptic, sub-synaptic, and organelle measures were highly consistent with findings from experimental models that are free from antemortem or postmortem effects. Further, 3D neuropil reconstruction revealed a unique spiny dendritic shaft that exhibited several ultrastructural features characteristic of neuronal segments engaged in synaptic plasticity. Altogether, our findings provide critical proof-of-concept data demonstrating that ex vivo VEM analysis appears as an effective approach to infer in vivo synaptic functioning in human brain.

Local protein synthesis in axons and dendrites underpins synaptic plasticity. However, the composition of the protein synthesis machinery in distal neuronal processes and the mechanisms for its activity-driven deployment to local translation sites remain unclear. Here, we employed cryo-electron tomography, volume electron microscopy, and live-cell imaging to identify Ribosome-Associated Vesicles (RAVs) as a dynamic platform for moving ribosomes to distal processes. Stimulation via chemically-induced long-term potentiation causes RAV accumulation in distal sites to drive local translation. We also demonstrate activity-driven changes in RAV generation and dynamics in vivo, identifying tubular ER shaping proteins in RAV biogenesis. Together, our work identifies a mechanism for ribosomal delivery to distal sites in neurons to promote activity-dependent local translation.

Journal Article Cryo-FIB and Synchrotron SAXS/WAXS Studies of Confined Crystallization of PDMS in Tubular Network Block Copolymer Morphologies Get access Vivek Subramanian, Vivek Subramanian Materials Science and Engineering, Texas A&M University, College Station, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Ken Wu, Ken Wu Materials and Structural Analysis Division, Thermo Fisher Scientific, Hillsboro, OR, USA Search for other works by this author on: Oxford Academic Google Scholar Xueyan Feng, Xueyan Feng Department of Macromolecular Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, China Search for other works by this author on: Oxford Academic Google Scholar Esther Tsai, Esther Tsai Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA Search for other works by this author on: Oxford Academic Google Scholar Ruipeng Li, Ruipeng Li National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA Search for other works by this author on: Oxford Academic Google Scholar Guillaume Freychet, Guillaume Freychet National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA Search for other works by this author on: Oxford Academic Google Scholar Mikhail Zhernenkov, Mikhail Zhernenkov National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA Search for other works by this author on: Oxford Academic Google Scholar Anindito Sen, Anindito Sen Microscopy and Imaging Centre (MIC), Texas A&M University, College Station, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Avery Mcintosh, Avery Mcintosh Microscopy and Imaging Centre (MIC), Texas A&M University, College Station, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Edwin L Thomas Edwin L Thomas Materials Science and Engineering, Texas A&M University, College Station, TX, USA Corresponding author: elt@tamu.edu Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Pages 523–525, https://doi.org/10.1093/micmic/ozad067.246 Published: 22 July 2023

The underlying causes of heart valve related-disease (HVD) are elusive. Murine animal models provide an excellent tool for studying HVD, however, the surgical and instrumental expertise required to accurately quantify the structure and organization across multiple length scales have stunted its advancement. This work provides a detailed description of the murine dissection, en bloc staining, sample processing, and correlative imaging procedures for depicting the heart valve at different length scales. Hydrostatic transvalvular pressure was used to control the temporal heterogeneity by chemically fixing the heart valve conformation. Micro-computed tomography (µCT) was used to confirm the geometry of the heart valve and provide a reference for the downstream sample processing needed for the serial block face scanning electron microscopy (SBF-SEM). High-resolution serial SEM images of the extracellular matrix (ECM) were taken and reconstructed to provide a local 3D representation of its organization. µCT and SBF-SEM imaging methods were then correlated to overcome the spatial variation across the pulmonary valve. Though the work presented is exclusively on the pulmonary valve, this methodology could be adopted for describing the hierarchical organization in biological systems and is pivotal for the structural characterization across multiple length scales.

Journal Article A Correlative Imaging Approach for Extracellular Matrix Characterization in Mice Get access Yifei Liu, Yifei Liu Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, OH, USA Corresponding author: liu.612@osu.edu Search for other works by this author on: Oxford Academic Google Scholar Yong-Ung Lee, Yong-Ung Lee Nationwide Children's Hospital, Center for Regenerative Medicine, Columbus, OH, USA Search for other works by this author on: Oxford Academic Google Scholar Tai Yi, Tai Yi Nationwide Children's Hospital, Center for Regenerative Medicine, Columbus, OH, USA Search for other works by this author on: Oxford Academic Google Scholar Ken Wu, Ken Wu Thermo Fisher Scientific, Hillsboro, OR, United States Search for other works by this author on: Oxford Academic Google Scholar Cedric Bouchet-Marquis, Cedric Bouchet-Marquis Thermo Fisher Scientific, Hillsboro, OR, United States Search for other works by this author on: Oxford Academic Google Scholar Han Chan, Han Chan Thermo Fisher Scientific, Hillsboro, OR, United States Search for other works by this author on: Oxford Academic Google Scholar Christopher K Breuer, Christopher K Breuer Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, OH, USANationwide Children's Hospital, Center for Regenerative Medicine, Columbus, OH, USA Search for other works by this author on: Oxford Academic Google Scholar David W McComb David W McComb Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, OH, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 25, Issue S2, 1 August 2019, Pages 1134–1135, https://doi.org/10.1017/S1431927619006408 Published: 01 August 2019