Biology subjects

Liao, Y.-H.

Publications and source records attributed to Liao, Y.-H..

4 recordsLinked to original sources

bioRxiv2026

Gpnmb-positive lipid-associated macrophages contribute to lipid clearance during luteolysis

Macrophages are important regulators of ovarian physiology, yet the complexity in their subpopulations and functions is far from fully understood and is emerging from single-cell analysis of diverse physiological and pathological contexts. One open question in ovarian physiology is how massive lipid loads during structural luteolysis are resolved without inducing inflammation. Here, by integrating single-cell and spatial transcriptomic datasets from mouse and human ovaries with high-resolution immunostaining and whole-mount imaging, we identified a Gpnmb+ subset of macrophages that dynamically expand during luteolysis in the mouse ovary, and a similar GPNMB+ macrophage population is also present in human ovarian scRNA-seq datasets. Transcriptomic profiling revealed that these Gpnmb+ macrophages resemble lipid-associated macrophages (LAMs) in adipose tissues in obesity, displaying strong enrichment in phagocytosis, lysosomal lipid processing, and reverse cholesterol transport. Notably, unlike phagocytic macrophages that only clear cellular debris, Gpnmb+ macrophages represent a distinct, specialized subset dedicated to processing lipid-rich targets: they selectively infiltrate regressing corpora lutea (CL), internalizing lipid droplets and interacting with dying luteal cells via apoptosis (Thbs1-Sdc1/4), efferocytosis (Pros1-Mertk), and cell recruitment (Cxcl12/Cxcr4) signaling axes. Gpnmb+ macrophages also surround oocytes in atretic follicles. Through integrated transcriptomic and imaging analyses, our data suggest that Gpnmb+ macrophages execute a complete cascade of multi-stepped lipid processing, including lipid droplet internalization, lysosomal and lipophagic degradation, and ABCA1/ABCG1-mediated cholesterol efflux. Furthermore, whole-mount imaging revealed close physical interaction between Gpnmb+ macrophages and LYVE1+ lymphatic endothelial cells, supporting a non-inflammatory resolution for lipid clearance via lymphatic circulation. Collectively, our findings establish Gpnmb+ macrophages as specialized LAMs essential for maintaining cyclic ovarian lipid homeostasis. This work redefines the paradigm of LAM biology by demonstrating their vital homeostatic role in normal ovarian physiology, bridging immune-mediated tissue remodeling and reproductive physiology.

physiology↗

bioRxiv2025

Phosphatidylinositol Transfer Protein-1 Integrates Insulin/IGF-1 and TOR Signaling to Negatively Regulate Lifespan and Healthspan in Caenorhabditis elegans

BackgroundPhosphatidylinositol transfer protein-1 (pitp-1) is involved in phosphoinositide turnover. The role of pitp-1 in promoting healthy longevity remains unknown. Our previous work showed that the phosphoinositide turnover genes dagl-1 and dgk-5 regulates lifespan, as overexpression of dagl-1 or knockdown of dgk-5 prolongs lifespan and enhances oxidative stress resistance through TOR signaling. As pitp-1 is a key component of this pathway, we investigated its role in lifespan regulation and the underlying mechanisms, aiming to clarify whether it represents a critical regulator of healthy longevity and how it coordinates conserved signaling pathways to regulate aging. MethodsC. elegans mutants, RNAi-mediated knockdown, and transgenic overexpression were applied to assess lifespan, motility, stress resistance. Temporal and tissue-specific RNAi were applied to identify the critical time window and tissue for pitp-1-mediated lifespan regulation. TOR signaling was measured by phosphorylated S6 kinase and puromycin incorporation, and transcriptomic analysis identified affected pathways. Resultspitp-1 negatively regulates lifespan and healthspan in Caenorhabditis elegans. Genetic deletion or RNAi-mediated knockdown of pitp-1 extends lifespan, attenuates age-related motility decline, and increases oxidative stress resistance. Temporal and spatial analyses reveal that suppression of pitp-1 in neurons during early adulthood is sufficient to promote healthy longevity. Mechanistically, these beneficial effects upon pitp-1 reduction are mediated by suppressing TOR signaling. Conversely, pitp-1 overexpression shortens lifespan and impairs healthspan via TOR activation. Moreover, pitp-1 is transcriptionally repressed by DAF-16 downstream of insulin/IGF-1 signaling (IIS), and contributes to IIS-mediated lifespan extension. ConclusionThese findings identify pitp-1 as a novel regulator of healthy aging that integrates IIS and TOR pathways, providing new insights into conserved mechanisms for promoting healthy longevity.

genetics↗

bioRxiv2022

A Noninvasive Skin Biopsy of Free Nerve Endings via Realtime Third-Harmonic Microscopy

Skin biopsy was the only method to provide free-intraepidermal-nerve-endings (FINEs) structural information for the differential diagnosis of small fiber neuropathy (SFN). Its invasive nature was particularly unfavorable for patients with diabetic coagulation abnormalities thus there is an unmet clinical need for a non-invasive FINEs imaging tool. Here we show a tightly-focused epi-Third-harmonic-generation microscope (TFETM) for unmyelinated FINEs imaging. Its label-free capability was confirmed by PGP9.5 immunohistochemistry staining and a longitudinal spared nerve injury model study. Moreover, through proposing a dot-connecting algorithm, we established the operational protocol to count three-dimensionally the intraepidermal nerve fibers (IENF) and define the quantitative IENF index. Our clinical trial showed that the label-free IENF index can differentially identify SFN (P-value=0.0102) and was well correlated with IENF density of skin biopsy (Pearsons correlation, R-value= 0.98) in the DPN group. Our study suggested that the unstained dot-connecting third-harmonic microscopy imaging can noninvasively provide FINEs structure information assisting diagnosing SFN.

bioengineering↗

bioRxiv2019

Characterization of Single Protein Dynamics in Cell Plasma Membrane Derived Polymer Cushioned Lipid Bilayers

Native cell membrane derived supported lipid bilayers (SLBs) are emerging platforms that have broad applications ranging from fundamental research to next-generation biosensors. Central to the success of the platform is proper accommodation of membrane proteins so that their dynamics and functions are preserved. Polymer cushions have been commonly employed to avoid direct contact of the bilayer membrane to the supporting substrate, and thus the mobility of transmembrane proteins is maintained. However, little is known about how the polymer cushion affects the absolute mobility of membrane molecules. Here, we characterized the dynamics of single membrane proteins in polymer-cushioned lipid bilayers derived from cell plasma membranes and investigated the effects of polymer length. Three membrane proteins of distinct structures, i.e., GPI-anchored protein, single-pass transmembrane protein CD98 heavy chain, and seven-pass transmembrane protein SSTR3, were fused with green fluorescence proteins (GFPs) and their dynamics were measured by fluorescence single-molecule tracking. An automated data acquisition was implemented to study the effects of PEG polymer length to protein dynamics with large statistics. Our data showed that increasing the PEG polymer length (molecular weight from 1,000 to 5,000) enhanced the mobile fraction of the membrane proteins. Moreover, the diffusion coefficients of transmembrane proteins were raised by increasing the polymer length, whereas the diffusion coefficient of GPI-anchored protein remained almost identical with different polymer lengths. Importantly, the diffusion coefficients of the three membrane proteins became identical (2.5 m2/s approximately) in the cushioned membrane with the longest polymer length (molecular weight of 5,000), indicating that the SLBs were fully suspended from the substrate by the polymer cushion at the microscopic length scale. Transient confinements were observed from all three proteins, and increasing the polymer length reduced the tendency of transient confinements. The measured dynamics of membrane proteins were found to be nearly unchanged after depletion of cholesterol, suggesting that the observed immobilization and transient confinement were not due to cholesterol-enriched membrane nanodomains (lipid rafts). Our single-molecule dynamics elucidate the biophysical properties of polymer cushioned plasma membrane bilayers that are potentially useful for future developments of membrane-based biosensors and analytical assays.

biophysics↗