Biology subjects

Liao, J.-C.

Publications and source records attributed to Liao, J.-C..

7 recordsLinked to original sources

bioRxiv2026

Single Cell-Type Spatial Proteomics Uncovers Regional Heterogeneity of Astrocytes

Astrocytes are a subset of glial cells in the central nervous system (CNS) that support numerous processes essential for brain function. Their functional diversity is thought to arise from specialized subpopulations with distinct molecular profiles. Although single-cell and single-nucleus RNA sequencing (scRNA-seq and snRNA-seq) have greatly advanced our understanding of astrocyte transcriptomic heterogeneity, mRNA abundance does not always correlate with protein levels because of post-transcriptional and translational regulation. Therefore, studying protein profiles remains essential to accurately capture astrocyte functional states and heterogeneity. Here, we used Microscoop Mint, a microscopy-guided spatial proteomics platform that integrates subcellular, region-specific sample preparation with LC-MS/MS-based mass spectrometry, enabling direct protein profiling of astrocytes in paraformaldehyde-fixed, optimal cutting temperature (OCT)-embedded mouse brain tissue. By applying this approach, we uncovered distinct regional-associated astrocyte proteomic signatures in the cerebral cortex and hippocampus and selected novel candidate protein markers for subsequent validation by immunofluorescence. Notably, MINK1 and PLEKHB1 showed preferential expression in hippocampal and cortical astrocytes, respectively, highlighting their potential as region-specific astrocyte markers. Overall, this strategy enables high-precision, unbiased spatial proteomic discovery at subcellular resolution, providing a powerful framework for linking molecular diversity to functional specialization in astrocyte biology.

neuroscience↗

bioRxiv2025

Microscopy-Guided Spatial Proteomics Reveals Novel Proteins at the Mitochondria-Lipid Droplet Interface and Their Role in Lipid Metabolism

Mitochondria-lipid droplet (LD) interactions play a critical role in lipid metabolism and the progression of metabolic diseases such as non-alcoholic fatty liver disease (NAFLD). However, the dynamic nature of these interactions has hindered the identification of novel protein constituents and their functional roles. Here, we employed Microscoop Mint, an advanced microscopy-guided spatial proteomics platform, to isolate proteins localized at mitochondria-LD contact sites in oleic acid (OA)-treated HepG2 cells, an in vitro model for studying fatty liver disease. Microscoop Mint integrates high-resolution image analysis and two-photon illumination to achieve precise biotinylation of proteins at subcellular regions of interest. Coupled with mass spectrometry, this approach identified a proteome enriched at the mitochondria-LD interface, including both well-characterized lipid-associated proteins and previously unrecognized candidates. Among the 373 common proteins identified across replicates, five novel candidates with no prior association to lipid metabolism were selected for validation. Immunofluorescence staining confirmed their localization at mitochondria-LD contact sites, with more pronounced association in OA-treated cells. Notably, suppression of one candidate, FHL3, led to reduced LD size, elongated mitochondrial morphology, and diminished mitochondria-LD interactions, suggesting its role in regulating fatty acid {beta}-oxidation. Our findings demonstrate the utility of Microscoop Mint in unveiling novel molecular players at organelle contact sites. This study not only provides insights into the functional dynamics of mitochondria-LD interactions but also highlights potential therapeutic targets for lipid metabolic disorders and NAFLD.

cell biology↗

bioRxiv2023

Microscopy-guided subcellular proteomic discovery by high-speed ultra-content photo-biotinylation

Microscopy-guided proteomics at an organelle-dimension resolution is desired for revealing unknown protein constituents at specific disease- or functional-associated regions at the molecular-molecular interactions level. Here, we achieve protein spatial purification by introducing a firmware-integrated microscopy platform that triggers in situ subcellular photo-biotinylation of proteins at user-defined regions of interest (ROIs) one field of view (FOV) at a time for thousands of FOVs fully automatically. An illumination pattern at the analogous ROIs of each FOV is calculated on the fly by either machine learning or traditional image processing. Photoactivatable amino acid crosslinkers are activated by a two-photon focal light one spot at a time at a sub-millisecond illumination duration per spot. Imaging, pattern generation, targeted illumination, and FOV movement are coordinated and cycled with high-speed mechatronic control to complete illumination on millions of ROI spots within hours. Once enough proteins are biotinylated in a cell or tissue sample, the sample is scraped and lysed, and avidin pulldown is used to enrich proteins to achieve spatial protein scooping at a 240-nm precision. Subsequent LC-MS/MS is implemented to reveal the subcellular proteome in high sensitivity, specificity, and resolution. Using this technology termed optoproteomics, we have revealed novel stress granule-localized and amyloid {beta}-localized proteins validated by immunostaining. Together, spatial purification by ultra-content, high-speed microscopy-targeted photo-biotinylation enables unprecedented subcellular spatial proteomics discovery in any microscopically recognizable regions.

cell biology↗

bioRxiv2021

INPP5E regulates CD3ζ enrichment at the immune synapse by phosphoinositide distribution control

The immune synapse, a specialized interface formed between T lymphocytes and antigen-presenting cells (APCs) after antigen recognition, is essential for T cell activation and the adaptive immune response. It has been shown that this interface shares similarities with the primary cilium, a sensory organelle in eukaryotic cells, although roles of ciliary proteins on the immune synapse remain elusive. In this study, we find that inositol polyphosphate-5-phosphatase E (INPP5E), a cilium-enriched protein responsible for regulating phosphoinositide localization, accumulated at the immune synapse during antigen-specific conjugation or antibody capping, and formed a complex with CD3{zeta}, ZAP-70, and Lck. Silencing INPP5E in T-cells impaired polarized distribution of CD3{zeta} at the immune synapse, and correlated with a failure of PI(4,5)P2 clearance at the center of the synapse. Moreover, INPP5E silencing decreased proximal TCR signaling, including phosphorylation of CD3{zeta} and ZAP-70, and finally, attenuated IL-2 secretion. Our results suggest that INPP5E is a new player in phosphoinositide manipulation at the synapse, controlling the TCR signaling cascade.

cell biology↗

bioRxiv2020

Epigenetic therapy remodels the immune synaptic cytoskeleton to potentiate cancer susceptibility to γδ T cells

{gamma}{delta} T cells are a distinct subgroup of T cells that bridge the innate and adaptive immune systems and can attack cancer or virus-infected cells in an MHC-unrestricted manner. Despite its antitumor ability in both autologous and allogeneic settings, earlier trials of adoptive {gamma}{delta} T cell transfer in solid tumors had limited success due to limitations in cell expansion and the lack of a strategy to modulate tumor lytic interactions between {gamma}{delta} T and cancer cells. Here, we show through quantitative surface proteomics and gene enrichment analyses that DNA methyltransferase inhibitors (DNMTis) upregulate multiple surface molecules related to {gamma}{delta} T cell activation in cancer cells. DNMTi treatment of human lung cancer potentiates tumor lysis by ex vivo-expanded {gamma}{delta} T cells using a clinical-grade expansion protocol developed by our team to enrich for the V{delta}1 subset while preserving their antitumor effector functions. Mechanistically, DNMTis enhance immune synapse formation and stabilize the synaptic cleft to facilitate {gamma}{delta} T-mediated tumor lysis. Through integrated analysis of RNA-seq, DNA methylation, and ATAC-seq, we demonstrate that depletion of DNMTs induces coordinated pattern alterations of immune synaptic-cytoskeletal networks at the cancer side of the immune synapse. In addition, single-cell mass cytometry reveals enrichment of polyfunctional {gamma}{delta} T subsets by DNMTis. Combined DNMTi and adoptive {gamma}{delta} T transfer in a mouse lung cancer model offers a significant survival benefit. Consistently, the DNMTi-associated cytoskeleton signature identifies a subset of lung cancer patients with improved survival. Our results demonstrate that epigenetic mechanisms are crucial for cytoskeletal remodeling in cancer to potentiate immune attack and support a combinatorial strategy of DNMTis and {gamma}{delta} T cell-based immunotherapy in lung cancer management. One Sentence SummaryDNA methyltransferase inhibitors potentiate the killing of lung cancer by {gamma}{delta} T cells through remodeling cytoskeletal-immune synaptic networks.

cancer biology↗

bioRxiv2017

Intraflagellar transport proteins undergo nonaxonemal staged hindrance between the recruiting distal appendages and the cilium

Primary cilia play a vital role in cellular sensing and signaling [1]. An essential component of ciliogenesis is intraflagellar transport (IFT), which first requires IFT-protein recruitment, IFT-protein-motor-protein assembly, axonemal engagement of IFT-protein complexes, and transition zone (TZ) gating [2-9]. The mechanistic understanding of these processes at the ciliary base was largely missing, because it is exceedingly challenging to observe the motion of IFT proteins in this crowded region using conventional microscopy. Here, we report short trajectory tracking of IFT proteins at the base of mammalian primary cilia by optimizing single-particle tracking photoactivated localization microscopy (sptPALM) [10, 11], balancing the imaging requirements of tracking speed, tracking duration, and localization precision for IFT88-mEOS4b in live human retinal pigment epithelial (hTERT-RPE-1) cells. Intriguingly, we found that mobile IFT proteins \"switched gears\" multiple times from the distal appendages (DAPs) to the ciliary compartment (CC), moving slowly in the DAPs, relatively fast in the proximal TZ, slowly again in the distal TZ, and then much faster in the CC. They could travel through the space between the DAPs and the axoneme without following DAP structures, and reached the space enveloped by the ciliary pocket in the proximal TZ. Together, our live-cell superresolution imaging revealed region-dependent slowdown of IFT proteins at the ciliary base, shedding light on staged control of ciliogenesis homeostasis.

biophysics↗

bioRxiv2017

Architecture of mammalian centriole distal appendages accommodates distinct blade and matrix functional elements

Distal appendages (DAPs) are nanoscale, pinwheel-like structures protruding from the distal end of the centriole that mediate membrane docking during ciliogenesis, marking the cilia base around the ciliary gate. Here, we determined a superresolved multiplex of 16 centriole-distal-end components. Surprisingly, rather than pinwheels, intact DAPs exhibit a cone-shaped architecture with components filling the space between each pinwheel blade, a new structural element we termed the distal appendage matrix (DAM). Specifically, CEP83, CEP89, SCLT1, and CEP164 form the backbone of pinwheel blades, with CEP83 confined at the root and CEP164 extending to the tip near the membrane-docking site. By contrast, FBF1 marks the distal end of the DAM near the ciliary membrane. Strikingly, unlike CEP164 which is essential for ciliogenesis, FBF1 is required for ciliary gating of transmembrane proteins, revealing DAPs as an essential component of the ciliary gate. Our findings redefine both the structure and function of DAPs.

cell biology↗