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Biomedical subjects

Peixiong Yuan

Publications and source records attributed to Peixiong Yuan.

6 recordsLinked to original sources

Time-dependent effects of rapid-acting antidepressants in iPSC-derived neurons from treatment-resistant depression and healthy volunteers.

Rapid-acting antidepressants like ketamine and serotonergic psychedelics show promise for treatment-resistant depression (TRD), but the molecular mechanisms that contribute to their therapeutic effects remain unclear. Induced pluripotent stem cells (iPSCs) offer a platform to model human cortical neurons and investigate drug effects in a human-relevant system. Here, iPSCs from individuals with TRD and healthy volunteers (HVs) were differentiated into mature cortical-like neurons and treated for six and 24 h with agents being investigated as rapid-acting antidepressants, including (2 R,6 R)-hydroxynorketamine (HNK), psilocybin, lysergic acid diethylamide (LSD), and 2,5-Dimethoxy-4-iodoamphetamine (DOI). Bulk and single-cell RNA sequencing assessed global and cell-type-specific transcriptomic responses. Synaptic proteins were evaluated via Western blotting and immunocytochemistry. To validate translational relevance, transcriptomic results were compared to CSF proteomics from ketamine-treated HVs. Despite differing initial pharmacological targets, overall gene expression across all compounds was highly correlated at matched timepoints compared to vehicle control, suggesting shared downstream effects. Both glutamatergic and serotonergic drugs converged on pathways involving inflammation, mTORC1 signaling, and cellular growth. At the single-cell level, (2 R,6 R)-HNK showed distinct cell-type specific alterations: upregulation in excitatory neurons and concomitant downregulation of inhibitory neuron populations. Differentially expressed genes from (2 R,6 R)-HNK-treated neurons also overlapped with CSF proteomic signatures from ketamine-treated individuals, supporting the model's translational relevance. This study is the first to assess multiple putative rapid-acting antidepressants in parallel using an iPSC-derived neuron model. Both convergent and drug-specific changes in gene expression and pathway enrichment were observed across diverse compounds, supporting the use of human iPSC-derived neurons in antidepressant drug discovery. Clinical Trial Registry: www.clinical trials.gov, NCT02484456.

Journal Article↗

Time-Dependent Effects of Rapid-Acting Antidepressants in iPSC-Derived Neurons from Treatment-Resistant Depression and Healthy Volunteers.

UNLABELLED: Rapid-acting antidepressants like ketamine and serotonergic psychedelics show promise for treatment-resistant depression (TRD), but the molecular mechanisms that contribute to their therapeutic effects remain unclear. Induced pluripotent stem cells (iPSCs) offer a platform to model human cortical neurons and investigate drug effects in a human-relevant system. Here, iPSCs from individuals with TRD and healthy volunteers (HVs) were differentiated into mature cortical-like neurons and treated for six and 24 hours with agents being investigated as rapid-acting antidepressants, including (2R,6R)-hydroxynorketamine (HNK), psilocybin, lysergic acid diethylamide (LSD), and 2,5-Dimethoxy-4-iodoamphetamine (DOI). Bulk and single-cell RNA sequencing assessed global and cell-type-specific transcriptomic responses. Synaptic proteins were evaluated via Western blotting and immunocytochemistry. To validate translational relevance, transcriptomic results were compared to CSF proteomics from ketamine-treated HVs. Despite differing initial pharmacological targets, overall gene expression across all compounds was highly correlated at matched timepoints compared to vehicle control, suggesting shared downstream effects. Both glutamatergic and serotonergic drugs converged on pathways involving inflammation, mTORC1 signaling, and cellular growth. At the single-cell level, HNK showed distinct cell-type specific alterations: upregulation in excitatory neurons and concomitant downregulation of inhibitory neuron populations. Differentially expressed genes from HNK-treated neurons also overlapped with CSF proteomic signatures from ketamine-treated individuals, supporting the model's translational relevance. This study is the first to assess multiple putative rapid-acting antidepressants in parallel using an iPSC-derived neuron model. Both convergent and drug-specific changes in gene expression and pathway enrichment were observed across diverse compounds, supporting the use of human iPSC-derived neurons in antidepressant drug discovery. CLINICAL TRIAL REGISTRY: www.clinicaltrials.gov, NCT02484456.

Journal Article↗

The role of the extracellular signal-regulated kinase signaling pathway in mood modulation.

The neurobiological underpinnings of mood modulation, molecular pathophysiology of manic-depressive illness, and therapeutic mechanism of mood stabilizers are largely unknown. The extracellular signal-regulated kinase (ERK) pathway is activated by neurotrophins and other neuroactive chemicals to produce their effects on neuronal differentiation, survival, regeneration, and structural and functional plasticity. We found that lithium and valproate, commonly used mood stabilizers for the treatment of manic-depressive illness, stimulated the ERK pathway in the rat hippocampus and frontal cortex. Both drugs increased the levels of activated phospho-ERK44/42, activated phospho-ribosomal protein S6 kinase-1 (RSK1) (a substrate of ERK), phospho-CREB (cAMP response element-binding protein) and phospho-B cell lymphoma protein-2 antagonist of cell death (substrates of RSK), and BDNF. Inhibiting the ERK pathway with the blood-brain barrier-penetrating mitogen-activated protein kinase (MAP kinase)/ERK kinase (MEK) kinase inhibitor SL327, but not with the nonblood-brain barrier-penetrating MEK inhibitor U0126, decreased immobility time and increased swimming time of rats in the forced-swim test. SL327, but not U0126, also increased locomotion time and distance traveled in a large open field. The behavioral changes in the open field were prevented with chronic lithium pretreatment. SL327-induced behavioral changes are qualitatively similar to the changes induced by amphetamine, a compound that induces relapse in remitted manic patients and mood elevation in normal subjects. These data suggest that the ERK pathway may mediate the antimanic effects of mood stabilizers.

Affect↗

Post-mortem interval effects on the phosphorylation of signaling proteins.

Post-mortem brain tissue provides a unique opportunity to uncover the genes or proteins involved in the pathophysiology of neuropsychiatric disorders. Protein phosphorylation is a common protein modification within intracellular signaling pathways that affects the distribution and function of protein, and has been hypothesized to be of major importance in both the pathophysiology and treatment of major neuropsychiatric disorders. Thus, we were interested in ascertaining the stability of the phosphorylated forms of proteins that are involved in cellular signaling. Antibodies against phospho-tyrosine, phospho-threonine, and phospho-PKA substrates were used to examine the PMI effects on the general amounts of proteins in their phosphorylated form. Phospho-specific antibodies for ERK, JNK, RSK, CREB, and ATF-2 were used to test the effects of PMI on specific proteins whose functioning are known to be regulated markedly by phosphorylation. We found that PMI rapidly decreased the levels of proteins in their phosphorylated states and also decreased the total levels of certain proteins. The PMI effects were observed in the samples stored at both 4 degrees C and room temperature, in both frontal cortex and hippocampus. Thus, it appears that measurements (such as two-dimensional gel electrophoresis and functional assays) that rely on the phosphorylation state of proteins would be extremely sensitive to PMI.

Animals↗

Structurally dissimilar antimanic agents modulate synaptic plasticity by regulating AMPA glutamate receptor subunit GluR1 synaptic expression.

A growing body of data from clinical and preclinical studies suggests that the glutamatergic system may represent a novel therapeutic target for severe recurrent mood disorders. Since synapse-specific glutamate receptor expression/localization is known to play critical roles in synaptic plasticity, we investigated the effects of mood stabilizers on AMPA receptor expression. Rats were treated chronically with lithium or valproate, hippocampal synaptosomes were isolated, and GluR1 levels were determined. Additionally, hippocampal neurons were prepared from E18 rat embryos and treated with lithium or valproate. Surface expression of GluR1 was determined using a biotinylation assay, and double-immunostaining with anti-GluR1 and anti-synaptotagmin antibodies was used to determine synaptic GluR1 levels. The AMPA receptor subunit GluR1 expression in hippocampal synaptosomes was significantly reduced by both chronic lithium and valproate. Overall, these studies show that AMPA receptor subunit GluR1 is a common target for two structurally highly dissimilar, but highly efficacious, mood stabilizers, lithium and valproate. These studies suggest that regulation of glutamatergically mediated synaptic plasticity may play a role in the treatment of mood disorders, and raise the possibility that agents more directly affecting synaptic GluR1 may represent novel therapies for this devastating illness.

Animals↗