Biology subjects

Tsai, C.-Y.

Publications and source records attributed to Tsai, C.-Y..

10 recordsLinked to original sources

bioRxiv2026

CaMKII-LUZP1 signaling couples cytoskeletal acetylation and autophagy to drive neuronal plasticity

Cytoskeletal acetylation and autophagy are fundamental drivers of neuronal plasticity, yet how these pathways are coordinated across subcellular compartments remains unknown. Here, we identify LUZP1 as a signaling organizer that couples cytoskeletal acetylation to autophagy in hippocampal neurons. LUZP1 deficiency impaired neurite outgrowth and dendritic spine maturation while promoting ciliary elongation; these phenotypes were partially mirrored in neuron-specific Luzp1 knockout mice, which also showed altered locomotor behavior. Mechanistically, LUZP1 promoted neurite extension by enhancing ATAT1-dependent -tubulin acetylation while driving spine maturation and limiting ciliary growth by restraining HDAC6-dependent cortactin (CTTN) deacetylation. An acetylation-mimetic CTTN mutant rescued both spine and ciliary defects caused by LUZP1 deficiency. In parallel, blocking autophagy-dependent OFD1 degradation attenuated ciliary elongation, linking CTTN deacetylation to increased autophagy under LUZP1-deficient conditions. Finally, activated CaMKII associated with LUZP1 and selectively enhanced its interaction with HDAC6 and CTTN, coupling neuronal activity to cytoskeletal remodeling. Together, these findings identify a CaMKII-LUZP1 pathway that integrates cytoskeletal acetylation with autophagy to coordinate neuronal morphogenesis and ciliary homeostasis. HighlightsO_LILUZP1 couples cytoskeletal acetylation to autophagy in hippocampal neurons C_LIO_LILUZP1 promotes neurite extension through ATAT1-dependent -tubulin acetylation C_LIO_LILUZP1 restrains HDAC6-CTTN signaling to drive spine maturation and limit ciliary growth C_LIO_LICaMKII selectively strengthens the LUZP1-HDAC6-CTTN pathway C_LI

neuroscience↗

bioRxiv2025

Rescuing Neurodevelopmental Deficits in AMPA Receptor Gain-of-Function Mutant

AMPA receptors (AMPARs) mediate fast excitatory synaptic transmission and are essential for neuronal development and brain function. We investigated the role of a recurrent variant in the AMPAR GluA1 subunit (GRIA1 p.A636T) identified in individuals with autism spectrum disorder (ASD) and intellectual disability (ID). To test causality and mechanism, we generated a Gria1-A636T knock-in mouse model. Mutant mice exhibited core ASD/ID-like behaviors and a selective hippocampal vulnerability characterized by progressive dendritic atrophy and neuronal loss. Despite reduced GluA1-containing complexes, AMPARs displayed synaptic hyperexcitability and failed to undergo the normal postnatal transition to calcium-impermeable AMPARs, resulting in persistent excitotoxicity. To explore therapeutic intervention, we designed an allele-specific antisense oligonucleotide to specifically silence the mutant transcript. A single neonatal administration of the antisense oligonucleotide entirely prevented hippocampal pathology and ameliorated behavioral deficits. These findings establish GRIA1-A636T as a gain-of-function mutation that drives developmental excitotoxicity and highlight the potential of RNA-targeted precision medicine for neurodevelopmental disorders.

neuroscience↗

bioRxiv2025

Dynamic and Heterogeneous Distribution of Trichomonasvirus Species in Trichomonas vaginalis

Trichomonasvirus (TVV) is a double-stranded RNA virus from the Pseudototiviridae family that exclusively infects Trichomonas vaginalis, the protozoan responsible for the most common non-viral sexually transmitted infection. Within the Trichomonasvirus genus, five distinct viral species have been identified, and intriguingly, a single T. vaginalis isolate can simultaneously harbor multiple TVV species. Previous studies have explored the impact of TVV infection on the physiology and virulence of T. vaginalis, yet findings remain inconsistent and often contradictory. We propose that these discrepancies stem from the heterogeneous intracellular distribution of TVV within individual cells of the same T. vaginalis isolate. To investigate this, we employed ultra-deep single-cell RNA sequencing and immunofluorescence assays to examine multiple T. vaginalis isolates. Our results revealed striking variability in the proportion of infected cells carrying the same viral species, even within a single isolate. The present study is the first to demonstrate the dynamic and non-uniform intracellular distribution of TVV at the single-cell level. These findings challenge previous assumptions and provide a new perspective on the intricate virus-host interactions between TVV and T. vaginalis, offering new avenues for further research into their complex relationship. Author SummaryTrichomonas vaginalis is a parasitic protozoan responsible for the most prevalent non-viral sexually transmitted infection worldwide. In 1985, researchers discovered a double-stranded RNA (dsRNA) virus within T. vaginalis, which was later named Trichomonasvirus (TVV). This virus is believed to influence the hosts gene expression, impacting cytoadherence, drug susceptibility, and virulence proteins. However, studies on TVV-host interaction have produced conflicting results, with some genes appearing upregulated in one experiment but downregulated in another or vice versa. We hypothesize that these inconsistencies stem from the non-uniform distribution of TVV among individual cells within the same T. vaginalis isolate. Based on the experimental data from ultra-deep single-cell sequencing and immuno-localization, our study reveals that TVVs intracellular distribution is highly heterogeneous and dynamic. These findings challenge the prevailing assumption that TVV is uniformly and statically distributed. This heterogeneity underscores the need to reassess previous research on TVV-T. vaginalis interactions, as earlier studies may have overlooked this crucial factor.

microbiology↗

bioRxiv2022

Computer simulations reveal pathogenicity and inheritance modes of hearing loss-causing germinal variants

Variants in the gap junction beta-2 (GJB2) gene are the most common cause of hereditary hearing impairment. However, how GJB2 variants lead to local physicochemical and structural changes in the hexameric ion channels of connexin 26 (Cx26), resulting in hearing impairment, remains elusive. In the present study, using molecular dynamics (MD) simulations, we showed that detached inner-wall N-terminal "plugs" aggregated to reduce the channel ion flow in a highly prevalent V37I variant in humans. To examine the predictability of the computational platform, an artificial mutant, V37M, of which the effect was previously unknown in hearing loss, was created. Microsecond simulations showed that homomeric V37M Cx26 hemichannels had an abnormal affinity between the inner edge and N-termini to block the narrower side of the cone-shaped Cx26, while the most stable heteromeric channels did not. Consistent with these predictions, homozygous V37M transgenic mice exhibited apparent hearing loss, but not their heterozygous counterparts, indicating a recessive inheritance mode. Reduced channel conductivity was found in Gjb2V37M/V37M outer sulcus cells and Claudius cells but not in Gjb2WT/WT cells. We view that the current computational platform could serve as an assessment tool for the pathogenesis and inheritance of GJB2-related hearing impairments and other diseases caused by connexin dysfunction.

biophysics↗

bioRxiv2022

FAM21 is critical for TLR2-CLEC4E-mediated dendritic cell function against Candida albicans

FAM21 (family with sequence similarity 21) is a component of the Wiskott-Aldrich syndrome protein and SCAR homologue (WASH) protein complex that mediates actin polymerization at endosomal membranes to facilitate sorting of cargo-containing vesicles out of endosomes. To study the function of FAM21 in vivo, we generated conditional knockout (cKO) mice in the C57BL/6 background in which FAM21 was specifically knocked out of CD11c-positive dendritic cells. Bone marrow-derived dendritic cells (BMDC) from those mice displayed enlarged early endosomes, and altered cell migration and morphology relative to wildtype (WT) cells. FAM21-cKO cells were less competent in phagocytosis and antigen processing in vitro, though antigen presentation was not affected. More importantly, we identified the TLR2/CLEC4E signaling pathway as being downregulated in FAM21-cKO BMDCs when challenged with its specific ligand Candida albicans. Moreover, FAM21-cKO mice were more susceptible to C. albicans infection than WT mice. Reconstitution of WT BMDCs in FAM21-cKO mice rescued them from lethal C. albicans infection. Thus, our study highlights the importance of FAM21 in a host immune response against a significant pathogen.

cell biology↗

bioRxiv2021

Impact of Glycosylation on SARS-CoV-2 Infection and Broadly Protective Vaccine Design

A major challenge to end the pandemic caused by SARS-CoV-2 is to develop a broadly protective vaccine. As the key immunogen, the spike protein is frequently mutated with conserved epitopes shielded by glycans. Here, we reveal that spike glycosylation has site-differential effects on viral infectivity and lung epithelial cells generate spike with more infective glycoforms. Compared to the fully glycosylated spike, immunization of spike protein with N-glycans trimmed to the monoglycosylated state (Smg) elicits stronger immune responses and better protection for hACE2 transgenic mice against variants of concern. In addition, a broadly neutralizing monoclonal antibody was identified from the Smg immunized mice, demonstrating that removal of glycan shields to better expose the conserved sequences is an effective and simple approach to broad-spectrum vaccine development. One-Sentence SummaryRemoving glycan shields to expose conserved epitopes is an effective approach to develop a broad-spectrum SARS-CoV-2 vaccine.

microbiology↗

bioRxiv2021

Sex-biased response to and brain cell infection by SARS-CoV-2 in a highly susceptible human ACE2 transgenic model

The COVID-19 pandemic is caused by SARS-CoV-2 infection. Human angiotensin-converting enzyme II (hACE2) has been identified as the receptor enabling SARS-CoV-2 host entry. To establish a mouse model for COVID-19, we generated transgenic mouse lines using the (HS4)2-pCAG-hACE2-HA-(HS4)2 transgene cassette, which expresses HA-tagged hACE2 under control of the CAG promoter and is flanked by HS4 insulators. Expression levels of the hACE2 transgene are respectively higher in lung, brain and kidney of our CAG-hACE2 transgenic mice and relatively lower in duodenum, heart and liver. The CAG-hACE2 mice are highly susceptibility to SARS-CoV-2 infection, with 100 PFU of SARS-CoV-2 being sufficient to induce 87.5% mortality at 9 days post-infection and resulting in a sole (female) survivor. Mortality was 100% at the higher titer of 1000 PFU. At lower viral titers, we also found that female mice exposed to SARS-CoV-2 infection suffered much less weight loss than male mice, implying sex-biased responses to SARS-CoV-2 infection. We subjected neuronal cultures to SARS-CoV-2 pseudovirus infection to ascertain the susceptibilities of neurons and astrocytes. Moreover, we observed that expression of SARS-CoV-2 Spike protein alters the synaptic responses of cultured neurons. Our transgenic mice may serve as a model for severe COVID-19 and sex-biased responses to SARS-CoV-2 infection, aiding in the development of vaccines and therapeutic treatments for this disease.

microbiology↗

bioRxiv2020

Toward the pathogenicity of the SLC26A4 p.C565Y variant using a genetically driven mouse model

Recessive variants of the SLC26A4 gene are a common cause of hearing impairment worldwide. In the past, cell lines and transgenic mice have been widely used to investigate the pathogenicity associated with the SLC26A4 variants. However, discrepancies in the pathogenicity between humans and cell lines or transgenic mice have been documented for some of the SLC26A4 variants. For instance, the p.C565Y variant, which has been reported to be pathogenic in humans, did not exhibit functional pathogenic consequences in cell lines. To address the pathogenicity of p.C565Y, we used a genotype-based approach in which we generated knock-in mice heterozygous (Slc26a4+/C565Y), homozygous (Slc26a4C565Y/C565Y), and compound heterozygous (Slc26a4919-2A>G/C565Y) for this variant. Subsequent phenotypic characterization revealed that mice segregating these genotypes demonstrated normal auditory and vestibular functions and normal inner ear morphology and expression of pendrin. These findings indicate that the p.C565Y variant is non-pathogenic for mice and that a single p.C565Y allele is sufficient to maintain normal inner ear physiology in mice. Our results highlight the differences in the pathogenicity associated with certain SLC26A4 variants between transgenic mice and humans, which should be taken into consideration while interpreting the results of animal studies for SLC26A4-related deafness.

genetics↗

bioRxiv2019

Data-Driven Design of Diagnostic Kits and Therapeutic Peptides

To ensure a physicochemically desired sequence motif to adapt a specific type of secondary structures, we compile an -helix database allowing complicate search patterns to facilitate a data-driven design of therapeutic peptides. Nearly 1.7 million helical peptides in >130 thousand proteins are extracted along with their interacting partners from the protein data bank (PDB). The sequences of the peptides are indexed with patterns and gaps and deposited in our Therapeutic Peptide Design dataBase (TP-DB). We here demonstrate its utility in three medicinal design cases. By our pattern-based search engine but not PHI-BLAST, we can identify a pathogenic protein, Helicobacter pylori neutrophil-activating protein (HP-NAP), a virulence factor of H. pylori, which contains a motif DYKYLE that belongs to the affinity determinant motif DYKXX[DE] of the FLAG-tag and can be recognized by the anti-FLAG M2 antibody. By doing so, the known purification-tag-specific antibody is repurposed into a diagnostic kit for H. pylori. Also by leveraging TP-DB, we discovered a stretch of helical peptide matching the potent membrane-insertion pattern WXXWXXW, elucidated by MD simulations. The newly synthesized peptide has a better minimal inhibitory concentration (MIC) and much lower cytotoxicity against Candida albicans (fungus) than that of previously characterized homologous antimicrobial peptides. In a similar vein, taking the discontinued anchoring residues in the helix-helix interaction interface as the search pattern, TP-DB returns several helical peptides as potential tumor suppressors of hepatocellular carcinoma (HCC) whose helicity and binding affinity were examined by MD simulations. Taken together, we believe that TP-DB and its pattern-based search engine provide a new opportunity for a (secondary-)structure-based design of peptide drugs and diagnostic kits for pathogens without inferring evolutionary homology between sequences sharing the same pattern. TP-DB is made available at http://dyn.life.nthu.edu.tw/design/.

bioinformatics↗

bioRxiv2017

Evolution and characterization of carboplatin resistance at single cell resolution

Acquired resistance to carboplatin is a major obstacle to the cure of ovarian cancer, but its molecular underpinnings are still poorly understood and often inconsistent between in vitro modeling studies. Using sequential treatment cycles, multiple clones derived from a single ovarian cancer cell reached similar levels of resistance. The resistant clones showed significant transcriptional heterogeneity, with shared repression of cell cycle processes and induction of IFN response signaling, and subsequent pharmacological inhibition of the JAK/STAT pathway led to a general increase in carboplatin sensitivity. Gene-expression based virtual synchronization of 26,772 single cells from 2 treatment steps and 4 resistant clones was used to evaluate the activity of Hallmark gene sets in proliferative (P) and quiescent (Q) phases. Two behaviors were associated with resistance: 1) broad repression in the P phase observed in all clones in early resistant steps and 2) prevalent induction in Q phase observed in the late treatment step of one clone. Furthermore, the induction of IFN response in P phase or Wnt-signaling in Q phase were observed in distinct resistant clones. These observations suggest a model of resistance hysteresis, where functional alterations of the P and Q phase states affect the dynamics of the successive transitions between drug exposure and recovery, and prompts for a precise monitoring of single-cell states to develop more effective schedules for, or combination of, chemotherapy treatments.

cancer biology↗