Biology subjects

Tsai, N.-P.

Publications and source records attributed to Tsai, N.-P..

5 recordsLinked to original sources

bioRxiv2026

Reduced MOV10 reveals novel functional cortical connections in an increased fear response

The RNA helicase MOV10 is highly expressed in developing brain, is present in synapses and is required for embryonic viability. A murine brain-specific knockout of MOV10 (Mov10 Deletion) has a thickened cortex, abnormal dendritic arborization and enhanced fear memory. In human studies, MOV10 is among the loci that is correlated with enhanced cortical brain volumes and is also significantly associated with substance dependence by epigenetic profiling. Here we demonstrate that Mov10 Deletion mice show enhanced fear learning that is aligned with impaired structural connectivity of canonical fear circuits revealed by Diffusion Tensor Imaging. We propose a model where MOV10 loss leads to increased GABRA2 expression in the hippocampus and reduced anatomical connectivity that drives augmented fear learning. Memory reactivation is observable during fear memory retrieval as an overall increase in fMRI functional activity in cortical regions. Taken together, this framework identifies that enhanced fear in the MOV10 model is driven via a "corticalized" fear response during re-exposure to the training context that is not driven by the canonical fear circuit. These findings support a molecular basis for non-traditional enhanced learning mechanisms activated by fearful events that shed light on the intractability of fear memories with the potential to inform PTSD and substance dependence disorders.

neuroscience↗

bioRxiv2026

Reversing Pathophysiology in Fragile X Syndrome Mice by Promoting PGC-1α and Mitochondrial Functions

Fragile X syndrome (FXS) is the leading cause of intellectual disabilities and autism, but a disease-modifying strategy remains unavailable. Recent studies have suggested reduced mitochondrial functions in FXS. However, the mechanisms underlying mitochondrial defects and their impact on FXS pathophysiology remain largely unclear. Here, we reveal a reduction in the mitochondrial master regulator peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1) in the mouse model of FXS, the Fmr1 knockout (KO) mice. We show that this impairment is caused by the inactivity of the transcription factor cAMP-response element-binding protein (CREB) in Fmr1 KO mice. Using the small molecule ZLN005, which induces AMP-activated protein kinase (AMPK)- and CREB-dependent elevation of PGC-1 in Fmr1 KO mice, we observed significantly increased mitochondrial functions and dynamics in cultured neurons in vitro and in the hippocampus in vivo. Furthermore, ZLN005 elicited a wide range of beneficial effects in Fmr1 KO mice, including enhanced inhibitory synaptic transmission, reduced circuit hyperexcitability, improved hippocampal synaptic plasticity, reduced cortical gamma-band oscillations, and improved interhemispheric coherence. Most importantly, we observed improved cognition and reduced autism-like behaviors in ZLN005-treated Fmr1 KO mice. Together, our findings identify AMPK-CREB signaling and PGC-1 as promising and selective therapeutic targets for FXS and reveal the broad impact of restoring PGC-1 on FXS pathophysiology. One Sentence SummaryPromoting PGC-1 Reverses FXS Pathophysiology.

neuroscience↗

bioRxiv2025

Modulating inter-mitochondrial contacts to increase membrane potential for mitigating blue light damage

Mitochondrial membrane potential (MMP) is essential for mitochondrial functions, yet current methods for modulating MMP lack precise spatial and temporal control. Here, we present an optogenetic system that enables reversible formation of inter-mitochondrial contacts (mito-contacts) with high spatiotemporal precision. Blue light stimulation induces rapid formation of mito-contacts, which fully dissipate upon cessation of illumination. These light-induced mito-contacts can enhance MMP, leading to increased ATP production under stress conditions. Moreover, in human retinal cells and C. elegans, high MMP induced by mito-contacts alleviates the deleterious effects of prolonged blue light exposure, restoring energy metabolism and extending organismal lifespan. This optogenetic approach provides a powerful tool for modulating MMP and offers potential therapeutic applications for diseases linked to mitochondrial dysfunction.

biophysics↗

bioRxiv2022

Enhancing Mitochondrial Functions by Optogenetic Clustering

Known as the powerhouses of cells, mitochondria and its dynamics are important for their functions in cells. Herein, an optogenetic method that controlling mitochondria to form the clusters was developed. The plasmid named CRY2PHR-mCherry-Miro1TM was designed for the optogenetic system. The photoactivable protein CRY2PHR was anchored to mitochondria, via the specific organelle-targeting transmembrane domain Miro1TM. Under blue light illumination, CRY2PHR can form the oligomerization, called puncta. With the illuminated time extended, the puncta can interact, and the mitochondria were found to form clustering with reversibility and spatiotemporal controllability. The mitochondrial functions were found to enhance after the formation of optogenetic mitochondrial clusters. This method presented here provides a way to control mitochondrial clustering and raise mitochondrial functions up.

cell biology↗

bioRxiv2019

Tmod2 is a regulator of cocaine responses through control of striatal and cortical excitability, and drug-induced plasticity

Drugs of abuse induce neuroadaptations, including synaptic plasticity, that are critical for transition to addiction, and genes and pathways that regulate these neuroadaptations are potential therapeutic targets. Tropomodulin 2 (Tmod2) is an actin-regulating gene that plays an important role in synapse maturation and dendritic arborization and has been implicated in substance-abuse and intellectual disability in humans. Here we mine the KOMP2 data and find that Tmod2 knockout mice show emotionality phenotypes that are predictive of addiction vulnerability. Detailed addiction phenotyping showed that Tmod2 deletion does not affect the acute locomotor response to cocaine administration. However, sensitized locomotor responses are highly attenuated in these knockouts, indicating perturbed drug-induced plasticity. In addition, Tmod2 mutant animals do not self-administer cocaine indicating lack of hedonic responses to cocaine. Whole brain MR imaging shows differences in brain volume across multiple regions although transcriptomic experiments did not reveal perturbations in gene co-expression networks. Detailed electrophysiological characterization of Tmod2 KO neurons, showed increased spontaneous firing rate of early postnatal and adult cortical and striatal neurons. Cocaine-induced synaptic plasticity that is critical for sensitization is either missing or reciprocal in Tmod2 KO nucleus accumbens shell medium spiny neurons, providing a mechanistic explanation of the cocaine response phenotypes. Combined, these data provide compelling evidence that Tmod2 is a major regulator of plasticity in the mesolimbic system and regulates the reinforcing and addictive properties of cocaine.\n\nSignificance statementWe identify, characterize, and establish tropomodulin 2 (Tmod2), an actin-regulating gene exclusively expressed in neurons, as an important regulator of addiction-related phenotypes. We show that Tmod2, knockout mice (Tmod2 KO) exhibit phenotypes that are predictive of addiction. In detailed addiction phenotyping, we find the Tmod2 regulates cocaine sensitization and self-administration. We explore anatomical, transcriptional, electrophysiological mechanisms of this regulation. Combined these studies provide compelling evidence that Tmod2 is critical for synaptic plasticity necessary for transition to addiction.

neuroscience↗