Publications by authors named "Kuei-Sen Hsu"

Irritability, a state of excessive reactivity to negative emotional stimuli, is common in individuals with autism spectrum disorder (ASD). Although it has a significant negative impact of patients' disease severity and quality of life, the neural mechanisms underlying irritability in ASD remain largely unclear. We have previously demonstrated that male mice lacking the Coiled-coil and C2 domain containing 1a (Cc2d1a) in forebrain excitatory neurons recapitulate numerous ASD-like behavioral phenotypes, including impaired social behaviors and pronounced repetitive behaviors.

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Background: Cathepsin S (CTSS) is a cysteine protease that played diverse roles in immunity, tumor metastasis, aging and other pathological alterations. At the cellular level, increased CTSS levels have been associated with the secretion of pro-inflammatory cytokines and disrupted the homeostasis of Ca flux. Once CTSS was suppressed, elevated levels of anti-inflammatory cytokines and changes of Ca influx were observed.

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Transient anoxia causes amnesia and neuronal death. This is attributed to enhanced glutamate release and modeled as anoxia-induced long-term potentiation (aLTP). aLTP is mediated by glutamate receptors and nitric oxide (·NO) and occludes stimulation-induced LTP.

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Hippocampal oxytocin receptor (OXTR) signaling is crucial for discrimination of social stimuli to guide social recognition, but circuit mechanisms and cell types involved remain incompletely understood. Here, we report a role for OXTR-expressing hilar mossy cells (MCs) of the dentate gyrus in social stimulus discrimination by regulating granule cell (GC) activity. Using a Cre-loxP recombination approach, we found that ablation of Oxtr from MCs impairs discrimination of social, but not object, stimuli in adult male mice.

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Inflammatory bowel disease (IBD) is a relapsing-remitting disorder characterized by chronic inflammation of the gastrointestinal (GI) tract. Anxiety symptoms are commonly observed in patients with IBD, but the mechanistic link between IBD and anxiety remains elusive. Here, we sought to characterize gut-to-brain signaling and brain circuitry responsible for the pathological expression of anxiety-like behaviors in male dextran sulfate sodium-induced (DSS-induced) experimental colitis mice.

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Transcranial direct current stimulation (tDCS) is a promising noninvasive neuromodulatory treatment option for multiple neurologic and psychiatric disorders, but its mechanism of action is still poorly understood. Adult hippocampal neurogenesis (AHN) continues throughout life and is crucial for preserving several aspects of hippocampal-dependent cognitive functions. Nevertheless, the contribution of AHN in the neuromodulatory effects of tDCS remains unexplored.

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Autism spectrum disorder (ASD) represents a heterogeneous group of neurodevelopmental disorders characterized by deficits in social communication, social interaction, and the presence of restricted repetitive behaviors. The cause of ASD involves complex interactions between genetic and environmental factors. Haploinsufficiency of the Coiled-coil and C2 domain containing 1A (Cc2d1a) gene is causally linked to ASD, and obesity has been associated with worse outcomes for ASD.

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Background: Social recognition memory (SRM) is the ability to distinguish familiar from novel conspecifics and is crucial for survival and reproductive success across social species. We previously reported that oxytocin (OXT) receptor (OXTR) signaling in the CA2/CA3a of dorsal hippocampus is essential to promote the persistence of long-term SRM, yet how the endogenous OXT system influences CA2 outputs to regulate long-term SRM formation remains unclear.

Methods: To achieve a selective deletion of CA2 OXTRs, we crossed Amigo2-Cre mice with Oxtr-floxed mice to generate CA2-specific Oxtr conditional knockout (Oxtr) mice.

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Background: Systemic inflammation is a potent contributor to increased seizure susceptibility. However, information regarding the effects of systemic inflammation on cerebral vascular integrity that influence neuron excitability is scarce. Necroptosis is closely associated with inflammation in various neurological diseases.

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The retrieval of recent and remote memories are thought to rely on distinct brain circuits and mechanisms. The retrosplenial cortex (RSC) is robustly activated during the retrieval of remotely acquired contextual fear memories (CFMs), but the contribution of particular subdivisions [granular (RSG) vs agranular retrosplenial area (RSA)] and the circuit mechanisms through which they interact to retrieve remote memories remain unexplored. In this study, using both anterograde and retrograde viral tracing approaches, we identified excitatory projections from layer 5 pyramidal neurons of the RSG to the CA1 stratum radiatum/lacunosum-moleculare of the dorsal hippocampus and the superficial layers of the RSA in male mice.

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Article Synopsis
  • Gene dosage imbalances from copy number variations (CNVs) in the 15q11.2 region are linked to autism and schizophrenia, but the mechanisms behind this association are not fully understood.* -
  • Researchers created mouse models to study the effects of both reduced and increased levels of the Cyfip1 gene, revealing unique and overlapping behavior issues related to autism and schizophrenia.* -
  • The study found that CYFIP1 influences NMDAR signaling at synapses, and correcting NMDAR imbalances in mice with altered Cyfip1 levels helped improve behavioral symptoms, shedding light on how CNV-induced gene dosage issues can lead to different brain disorders.*
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Biallelic loss-of-function mutations in Coiled-coil and C2 domain containing 1A (CC2D1A) cause autosomal recessive intellectual disability, sometimes comorbid with other neurodevelopmental disabilities, such as autism spectrum disorder (ASD) and seizures. We recently reported that conditional deletion of Cc2d1a in glutamatergic neurons of the postnatal mouse forebrain leads to impaired hippocampal synaptic plasticity and cognitive function. However, the pathogenic origin of the autistic features of CC2D1A deficiency remains elusive.

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Background: Transcranial direct current stimulation (tDCS) provides a noninvasive polarity-specific constant current to treat epilepsy, through a mechanism possibly involving excitability modulation and neural oscillation.

Objective: To determine whether EEG oscillations underlie the interictal spike changes after tDCS in rats with chronic spontaneous seizures.

Methods: Rats with kainic acid-induced spontaneous seizures were subjected to cathodal tDCS or sham stimulation for 5 consecutive days.

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We previously identified a causal link between a rare patient mutation in DISC1 (disrupted-in-schizophrenia 1) and synaptic deficits in cortical neurons differentiated from isogenic patient-derived induced pluripotent stem cells (iPSCs). Here we find that transcripts related to phosphodiesterase 4 (PDE4) signaling are significantly elevated in human cortical neurons differentiated from iPSCs with the DISC1 mutation and that inhibition of PDE4 or activation of the cAMP signaling pathway functionally rescues synaptic deficits. We further generated a knock-in mouse line harboring the same patient mutation in the Disc1 gene.

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In social animals, the behavioral and hormonal responses to stress can be transmitted from one individual to another through a social transmission process, and, conversely, social support ameliorates stress responses, a phenomenon referred to as social buffering. Metaplasticity represents activity-dependent synaptic changes that modulate the ability to elicit subsequent synaptic plasticity. Authentic stress can induce hippocampal metaplasticity, but whether transmitted stress has the same ability remains unknown.

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Episodic memories acquired early in life are fragile and rapidly forgotten in both humans and nonhuman animals. However, early life experiences have been documented to profoundly affect brain function and physiology throughout life, suggesting that in certain circumstances, the developing brain is capable of producing long-term memory (LTM). In this study, we asked whether exposure to a novel environment, a process named "behavioral tagging," may promote the persistence of weak memories in male juvenile mice.

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Status epilepticus (SE) is a state of prolonged and repeated seizures that can lead to permanent brain damage or life-threatening conditions. Transcranial direct current stimulation (tDCS) non-invasively provides a polarity-specific electric current to modulate brain excitability. Little is known about the therapeutic potential of tDCS in SE.

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Background: Research indicates that sepsis increases the risk of developing cognitive impairment. After systemic inflammation, a corresponding activation of microglia is rapidly induced in the brain, and multiple neurotoxic factors, including inflammatory mediators (e.g.

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Excitation-inhibition (E-I) imbalance is considered a hallmark of various neurodevelopmental disorders, including schizophrenia and autism. How genetic risk factors disrupt coordinated glutamatergic and GABAergic synapse formation to cause an E-I imbalance is not well understood. Here, we show that knockdown of Disrupted-in-schizophrenia 1 (DISC1), a risk gene for major mental disorders, leads to E-I imbalance in mature dentate granule neurons.

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Early life stress (ELS) can affect brain development and increase lifetime prevalence of psychiatric illnesses. However, the effective therapeutic interventions to ameliorate the deleterious effects of ELS have not yet been well established. Here, we confirmed that maternal separation (MS) for 3 h daily between postnatal days 2-14, a frequently used experimental model of ELS, resulted in early expression of adult-like fear memory retention in male infant rats.

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Coiled-coil and C2 domain containing 1A (CC2D1A) is an evolutionarily conserved protein, originally identified as a nuclear factor-κB activator through a large-scale screen of human genes. Mutations in the human gene result in autosomal recessive nonsyndromic intellectual disability. It remains unclear, however, how mutation leads to alterations in brain function.

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Long-term depression (LTD) of synaptic efficacy is widely regarded as a cellular basis of learning and memory. The magnitude of hippocampal CA1 LTD induced by low-frequency stimulation (LFS) declines with age, but the mechanisms involved remain poorly understood. Perineuronal nets (PNNs) are specialized extracellular matrix structures that function in dampening synaptic plasticity during postnatal development, suggesting that PNN formation may restrict LTD induction in the adult hippocampus.

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