Biology subjects

Chen, C.-M.

Publications and source records attributed to Chen, C.-M..

7 recordsLinked to original sources

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

Cytoskeleton remodeling caused by keratin dysregulation triggers tumor aggressiveness via promoting genomic instability and cellular adaption

Cellular architecture depends on keratin intermediate filament as a fundamental component, which offers essential mechanical support to fight environmental stresses. Our previous research demonstrated that keratin fusion variants increase tumor aggressiveness through enhanced cancer stemness in oral squamous cell carcinoma. The proper functioning of keratins plays an essential role in maintaining cell structure while determining cell fate. The present study demonstrates that keratin fusion variant drives genomic instability through cytokinesis defects, which results in the formation of polyaneuploid cancer cells (PACC). The cells expressing keratin fusion show elevated DNA damage repair gene expression, which serves as a key factor for mitotic slippage during cancer development. The PACCs generated by keratin fusion make cancer cells resistant to cisplatin treatment while simultaneously reducing {gamma}-H2AX induction and increasing survival rates. The Gene Set Enrichment Analysis results showed increased "regulation of actin cytoskeleton" activity in keratin fusion-expressing cells correlated with elevated actin filament networks and increased cell motility in these cells. In summary, the keratin fusion variant enhances cancer aggressiveness through three mechanisms: it creates genomic instability that leads to PACC formation and enables cancer cells to evade cGAS/STING-mediated death signals and modifies cytoskeleton structures, which results in drug resistance and metastasis.

cancer biology↗

bioRxiv2023

Video-rate three-photon imaging in deep Drosophila brain based on a single Cr:forsterite oscillator

We have demonstrated 30-Hz three-photon imaging using a single 24-MHz mode-locked Cr:forsterite oscillator with a center wavelength at 1260 nm. By managing the dispersion distribution in the resonator using double-chirped mirrors, we have produced 32-fs pulses with 22-nJ pulse energy. Using the oscillator as a driving source, we have realized multi-color three-photon images using a GFP-labeled Drosophila brain and an AF647-labeled mouse brain. To demonstrate the capability of deep-tissue imaging, we have obtained a 10-times higher SBR from the three-photon images than the two-photon results at different depths in a GFP-labeled Drosophila brain dissection. Furthermore, we have shown the impact of excitation pulse width on three-photon deep-tissue imaging. Our results indicate the superiority of using shorter pulses for deeper-tissue imaging, especially in the Drosophila brain. In addition, we have recorded the three-photon calcium imaging in vivo from the Drosophila mushroom body in response to external electric shocks. We believe our demonstration provides a robust approach for high-speed three-photon microscopy applications, especially for intravital investigations in the Drosophila brain.

bioengineering↗

bioRxiv2022

Aldo-Keto Reductase Family 1 Member A1 (AKR1A1) Deficiency Exacerbates Alcohol-Induced Hepatic Oxidative Stress, Inflammation, Steatosis, and Fibrosis

BackgroundAlcohol-associated liver disease (ALD) covers a wide range of hepatic lesions that depend on the amount and duration of alcohol consumption, from early and reversible conditions to hepatic steatosis and severe lesions, including steatohepatitis and alcoholic fibrosis, to irreversible cirrhosis. AKR1A1, an aldo-keto reductase family member, participates in the detoxification of alcohol-derived acetaldehyde, but its role in ALD remains unclear. In this study, we studied the role of AKR1A1 in the development of ALD using Akr1a1-/- knockout mice and palmitic acid/oleic acid (P/O) plus ethanol-treated AML12 hepatocyte cells. MethodsLevels of AKR1A1 were measured in mice fed with the Lieber-DeCarli diet containing 5% alcohol (alcohol-fed, AF) or control liquid diet (pair-fed, PF). The effects of AKR1A1 on the liver function, inflammation, oxidative stress, lipid accumulation, and fibrosis were assessed in AF-induced Akr1a1-/- and ICR control mice. ResultsData showed that AF-Akr1a1-/- mice exhibited an exacerbation of liver injury and increased gene and protein levels of inflammatory mediators, oxidative stress, lipid accumulation, and fibrosis, whilst decreased expression of antioxidant enzymes in their livers than the AF-ICR mice. Therefore, loss of AKR1A1 can activate 4-HNE/p53 signaling to modulate ROS and antioxidant balance, increase lipid peroxidation, fatty acid synthesis and lipid droplet formation, reduced fatty acid {beta}-oxidation, and elevated proinflammatory and fibrotic mediator, eventually exacerbate the ALD. In in vitro study, we further demonstrated that knockdown of Akrlal aggravated the effects of alcohol plus P/O-induced oxidative stress and steatosis, LPS-stimulated inflammation, and TGF-{beta}1-induced fibrosis in AML12 hepatocyte cells. Conclusionour results revealed that AKR1A1 exerts protective effects on alcohol-induced liver injury, steatosis, and fibrosis, possibly by regulating the 4-HNE-p53 signaling pathway.

pathology↗

bioRxiv2020

Multimodal imaging evidence for the brain basis of cognitive dysfunction in older HIV+ men

ObjectiveThis study used converging methods to define the structural and functional characteristics of the neural substrates underlying variation in cognitive ability in older men with well-controlled HIV infection. MethodsSeventy-six HIV+ men treated with combination antiretrovirals completed attention and inhibitory control tasks tapping different cortico-subcortical circuits while time-locked high-density EEG was acquired. Fifty-four also underwent structural MRI. We investigated relationships between task-evoked EEG responses, cognitive ability and immunocompromise. MRI suggested a subcortical basis for the observed EEG effects. ResultsEEG activity was associated with cognitive ability at later (P300) but not earlier processing stages of both tasks. However, only the P300 evoked by the attention task was associated with past HIV infection severity. Source localization confirmed that the tasks engaged different brain circuits. Thalamus volumes correlated with P300 amplitudes evoked by the attention task, while globus pallidus volumes were related to the P300 in both tasks. InterpretationThis is the first study to combine structural and functional imaging in an overlapping sample to address the neural circuits related to cognitive dysfunction in HIV. Neural substrates of attention were more affected than those supporting inhibitory control. Preliminary evidence suggests these differences may relate to vulnerability of the thalamus to the effects of HIV. Our results suggest high-yield tasks and circuit targets for future work.

neuroscience↗

bioRxiv2020

Fibroblast growth factor 9 stimulates neurite outgrowth through NF-kB signaling in striatal cell Huntington's disease models

Proper development of neuronal cells is important for brain functions, and impairment of neuronal development may lead to neuronal disorders, implying that improvement in neuronal development may be a therapeutic direction for these diseases. Huntingtons disease (HD) is a neurodegenerative disease characterized by impairment of neuronal structures, ultimately leading to neuronal death and dysfunctions of the central nervous system. Based on previous studies, fibroblast growth factor 9 (FGF9) may provide neuroprotective functions in HD, and FGFs may enhance neuronal development and neurite outgrowth. However, whether FGF9 can provide neuronal protective functions through improvement of neuronal morphology in HD is still unclear. Here, we study the effects of FGF9 on neuronal morphology in HD and attempt to understand the related working mechanisms. Taking advantage of striatal cell lines from HD knock-in mice, we found that FGF9 increases neurite outgrowth and upregulates several structural and synaptic proteins under HD conditions. In addition, activation of nuclear factor kappa B (NF-kB) signaling by FGF9 was observed to be significant in HD cells, and blockage of NF-kB leads to suppression of these structural and synaptic proteins induced by FGF9, suggesting the involvement of NF-kB signaling in these effects of FGF9. Taken these results together, FGF9 may enhance neurite outgrowth through upregulation of NF-kB signaling, and this mechanism could serve as an important mechanism for neuroprotective functions of FGF9 in HD.

neuroscience↗

bioRxiv2018

Lessening of porcine epidemic diarrhoea virus susceptibility in piglets after editing of the CMP-N-glycolylneuraminic acid hydroxylase gene with CRISPR/Cas9 to nullify N-glycolylneuraminic acid expression

Porcine epidemic diarrhoea virus (PEDV) devastates the health of piglets but may not infect piglets whose CMP-N-glycolylneuraminic acid hydroxylase (CMAH) gene mutated (knockouts, KO) by using CRISPR/Cas9 gene editing techniques. This hypothesis was tested by using KO piglets challenged with PEDV. Two single-guide RNAs targeting the CMAH gene and Cas9 mRNA were microinjected into the cytoplasm of newly fertilized eggs; 4 live founders generated and proven to be biallelic KO, lacking detectable N-glycolylneuraminic acid (NGNA). The founders were bred, and homozygous offspring were obtained. Two-day-old (in exps. I and III) and 3-day-old (in exp. II) KO and wild-type (WT) piglets were inoculated with TCID50 1x103 PEDV and then fed 20 mL of infant formula (in exps. I and II) or sows colostrum (in exp. III) every 4 hours. In exp. III, the colostrum was offered 6 times and was then replaced with Ringer/5% glucose solution. At 72 hours post-PEDV inoculation (hpi), the animals were euthanized for necropsy, and their intestines were sampled. In all 3 experiments, the piglets showed apparent outward clinical manifestations suggesting that infection occurred despite the CMAH KO. In exp. I, all 6 WT piglets and only 1 of 6 KO piglets died at 72 hpi. Histopathology and immunofluorescence staining showed that the villus epithelial cells of WT piglets were severely exfoliated, but only moderate exfoliation and enterocyte vacuolization was observed in KO piglets. In exp. II, delayed clinical symptoms appeared, yet the immunofluorescence staining/histopathologic inspection (I/H) scores of the two groups differed little. In exp. III, the animals exhibited clinical and pathological signs after inoculation similar to those in exp. II. These results suggest that porcine CMAH KO with nullified NGNA expression are not immune to PEDV but that this KO may lessen the severity of the infection and delay its occurrence.\n\nAuthor summaryThe infection of villus epithelial cells by PEDV has been suggested to occur via putative sialic acid and aminopeptidase N (APN) receptors. Thus, CMP-N-glycolylneuraminic acid hydroxylase (CMAH) gene-mutated pigs that lack N-glycolylneuraminic acid (NGNA) receptors should exhibit resistance to PEDV infection even when APN, which is also responsible for peptide digestion and amino acid absorption and should not be tackled and remains intact. This hypothesis was tested in the present study by generating animals of this type; however, after PEDV challenge, they still showed clinical manifestations of infection. Although the hypothesis could not be verified by the results of the study, some of the immunological and histopathological evidence obtained suggested that this genetic alteration may lessen the severity of infection and delay its occurrence. The results also suggested that binding to NGNA is not a sufficient and necessary condition for PEDV infection of enterocytes. The null expression of CMAH by gene editing induced insignificant resistance to PEDV infection in neonatal piglets.

epidemiology↗