👤 Yi-Yun Tai

Serotonergic psychedelics are re-emerging as therapeutic candidates across psychiatry, particularly for treatment-resistant depression. Their rapid and sustained antidepressant effects, alongside evidence for neuroplastic, dopaminergic, and glutamatergic modulation, have prompted interest in whether they could address depressive and negative symptoms in schizophrenia spectrum disorders (SSDs). This narrative review summarizes mechanistic, preclinical, and early clinical findings relevant to psychedelic use in SSDs. Schizophrenia and major depressive disorder share disturbances in dopamine, glutamate, and neuroplasticity, and both involve large-scale network abnormalities. Schizophrenia is associated with widespread dysconnectivity, mesocortical hypodopaminergia, and striatal hyperdopaminergia linked to NMDA receptor hypofunction. Depression is characterized by fronto-limbic and default mode network hyperconnectivity, mesolimbic hypodopaminergia, and reduced cortical glutamatergic tone. Depressive symptoms within SSDs may reflect an intermediate phenotype combining depressive-like hyperconnectivity with schizophrenia-related global dysconnectivity, suggesting that psychedelics' capacity to transiently increase network flexibility and recalibrate maladaptive connectivity may be clinically relevant. Preclinical studies show increased dendritic spine density, enhanced BDNF expression, restored reward sensitivity, and modulation of network dynamics after psychedelic administration. Clinically, uncontrolled exposure appears associated with increased psychosis-related presentations, whereas limited case reports suggest controlled administration may be tolerated in carefully selected, clinically stable individuals with SSDs. To date, only one early-phase trial (MDMA in schizophrenia) is ongoing, and no randomized trials have evaluated psilocybin or LSD in SSDs. Overall, psychedelics are biologically and mechanistically plausible but remain unproven for depressive and negative symptoms in SSDs, which partially overlap. Carefully designed, safety-focused early-phase studies in clinically stable patients are therefore a prerequisite for broader clinical application. Show less

Published data suggest that compared to APOE3, APOE4 could increase the risk of neurodegeneration via higher cerebrovascular permeability. We recently proposed the concept that brain endothelial cell APOE is protective for cerebrovascular function in a genotype specific manner, APOE3 > APOE4, and therefore APOE4 brain endothelial cells may be predisposed to dysfunction during aging and disease. In addition to mechanistic implications, our concepts and methods may have therapeutic applications; identifying compounds that protect APOE4 brain endothelial cells. The goal of this proof-of-concept study was to determine whether APOE4 brain endothelial cells can be used as a phenotypic compound screen. Previously we found that APOE4 brain endothelial cells are particularly sensitive to lipopolysaccharide- (LPS) induced permeability disruption when measured by trans endothelial cell electrical resistance (TEER) in vitro. Here, we followed the NIH Assay guidance manual to convert our in vitro assay to a phenotypic screen. We scaled the isolation protocol, selected conditions for the min, mid and max signals, statistically validated the phenotypic assay, screened compounds, validated hits and tested the top hits in vivo. We scaled the isolation protocol and selected conditions for min (0.8 µg/ml LPS), mid (10 µM sildenafil/LPS) and max conditions (vehicle). Our final protocol met the reproducibility acceptance criteria for a statistically validated assay. We then screened a subset of ~ 900 molecules from the TargetMol Bioactive Library and identified two main groups compounds. The first group disrupted APOE4 brain endothelial cells as they were toxic or lowered TEER and many inhibited mTOR. The second group protected against LPS-induced TEER reduction. With relatively stringent criteria we identified 33 protective compounds that are grouped into those that inhibit growth factor receptor signaling and a range of intracellular signaling pathways. We compared the most active compounds and selected four to test in vivo. Tadalafil (PDE5 inhibitor), vorinostat (HDAC inhibitor), CCT196969 (raf inhibitor) and SGI-7079 (AXL inhibitor) mitigated acute LPS-induced cerebrovascular dysfunction in mice that express APOE4. Overall, our data supports the potential of our in vitro screen to identify compounds that prevent LPS-induced dysfunction in APOE4 brain endothelial cells. Show less

This study aims to explore the plastic changes in cell lineages during the progression of osteoarthritis (OA) and their relationship with dysregulation of signaling pathways and provide new molecular targets for precise treatment. Single-cell RNA sequencing (scRNA-seq) technology was utilized to perform high-resolution cell lineage analysis of OA patients. The mappings of distinct cell subpopulations were systematically constructed and revealed the changes in key cell types and their transformation trajectories throughout the progression of OA. Furthermore, KEGG and GO enrichment and pseudotime trajectory analysis were applied to elucidate the functional reprogramming of different cell types and the dynamic imbalance of their signaling networks in OA. Additionally, in vitro experiments were conducted to validate the biological functions of candidate genes in OA. Articular cartilage showed a transcriptional cellular heterogeneity in OA by scRNA-seq analysis; the annotated PreFC, FC, and PreHTC subsets accounted for the main part of OA samples. PreFC cells revealed transcription, signaling, and metabolic reprogramming in OA; pseudotime trajectory found that PreFC transformed to FC cells under the condition of hypoxia and metabolic reprogramming, while fibrosis and ECM degradation pathways showed intense upregulation in preHTC evolved from PreFC cells. HIF1A and ANGPTL4 were identified as key molecular regulators of OA progression, contributing to ECM degradation, inflammation, and apoptosis in chondrocytes, as confirmed through functional validation. The cellular trajectories of OA show significant plasticity changes which are influenced by the dysregulation of multiple signaling pathways. This research provides new insights into the pathological process of OA and offers potential targets for therapeutic strategies targeting these abnormal mechanisms. Show less

The genetic basis of hypertriglyceridemia (HTG) is complex and includes variants in lipase maturation factor 1 (LMF1), an endoplasmic reticulum (ER)-chaperone involved in the post-translational activation of lipoprotein lipase (LPL). The objective of this study was to identify and functionally characterize biallelic LMF1 variants in patients with HTG. Genomic DNA sequencing was used to identify biallelic LMF1 variants in HTG patients without deleterious variants in LPL, apolipoprotein C-II (APOC2), glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) or apolipoprotein A-V (APOA5). LMF1 variants were functionally evaluated by in silico analyses and assessing their impact on LPL activity, LMF1 protein expression, and specific activity in transiently transfected HEK293 cells. We identified four homozygous LMF1 variants in patients with severe HTG: two novel rare variants (p.Asn147Lys and p.Pro246Arg) and two low-frequency variants (p.Arg354Trp and p.Arg364Gln) previously reported at heterozygosity. We demonstrate that all four variants reduce the secretion of enzymatically active LPL by impairing the specific activity of LMF1, whereas p.Asn147Lys also diminishes LMF1 protein expression. This study extends the role of LMF1 as a genetic determinant in severe HTG and demonstrates that rare and low-frequency LMF1 variants can underlie this condition through distinct molecular mechanisms. The clinical phenotype of patients affected by partial loss of LMF1 function is consistent with multifactorial chylomicronemia syndrome (MCS) and suggests that secondary factors and additional genetic determinants contribute to HTG in these subjects. Show less

Long noncoding RNAs (lncRNAs), non-protein-coding transcripts exceeding 200 nucleotides, are critical regulators of gene expression through chromatin remodeling, transcriptional modulation, and post-transcriptional modifications. While ionizing radiation (IR) induces cellular damage through direct DNA breaks, reactive oxygen species (ROS)-mediated oxidative stress, and bystander effects, the functional involvement of lncRNAs in the radiation response remains incompletely characterized. Here, through genome-wide CRISPR activation (CRISPRa) screening in non-small cell lung cancer (NSCLC) cells, we identified LOC401312 as a novel radiosensitizing lncRNA, the stable overexpression of which significantly enhanced IR sensitivity. Transcriptomic profiling revealed that LOC401312 transcriptionally upregulates carbamoyl-phosphate synthase 1 (CPS1), a mitochondrial enzyme involved in pyrimidine biosynthesis. Notably, CPS1 overexpression recapitulated the radiosensitization phenotype observed with LOC401312 activation. Mechanistic investigations revealed that CPS1 suppresses the phosphorylation of ATM kinase (Ser1981) protein, which is a key mediator of DNA damage checkpoint activation. This study established the LOC401312-CPS1-ATM axis as a previously unrecognized regulatory network governing radiation sensitivity, highlighting the potential of lncRNA-directed metabolic rewiring to impair DNA repair fidelity. Our findings not only expand the functional landscape of lncRNAs in DNA damage response but also provide a therapeutic rationale for targeting the LOC401312-CPS1 axis to improve radiotherapy efficacy in NSCLC. Show less

This study aims to explore the association between plasma metabolites and chronic kidney disease progression in individuals with type 2 diabetes. We performed a comprehensive metabolomic analysis in a prospective cohort study of 5144 multi-ancestral individuals with type 2 diabetes in Singapore, using eGFR slope as the primary outcome of kidney function decline. In addition, we performed genome-wide association studies on metabolites to assess how these metabolites could be genetically influenced by metabolite quantitative trait loci and performed colocalisation analysis to identify genes affecting both metabolites and kidney function. Elevated levels of 61 lipids with long unsaturated fatty acid chains such as phosphatidylethanolamines, triacylglycerols, diacylglycerols, ceramides and deoxysphingolipids were prospectively associated with more rapid kidney function decline. In addition, elevated levels of seven amino acids and three lipids in the plasma were associated with a slower decline in eGFR. We also identified 15 metabolite quantitative trait loci associated with these metabolites, within which variants near TM6SF2, APOE and CPS1 could affect both metabolite levels and kidney functions. Our study identified plasma metabolites associated with prospective renal function decline, offering insights into the underlying mechanism by which the metabolite abnormalities due to fatty acid oversupply might reflect impaired β-oxidation and associate with future chronic kidney disease progression in individuals with diabetes. Show less

Peritoneal metastasis (PM) in gastric cancer (GC) remains a formidable clinical challenge. Although exosomes are critical mediators of tumor-microenvironment communication, their mechanistic role in linking mesothelial-mesenchymal transition (MMT) to peritoneal dissemination remains poorly understood. This study elucidates a GC-derived exosomal microRNA (miRNA)-driven pathway that orchestrates peritoneal metastasis. Integrated exosomal miRNA sequencing and The Cancer Genome Atlas (TCGA) analysis identified miR-196a-5p as highly enriched in GC-derived exosomes. Functional assays, including in vitro co-culture experiments, and in vivo PM models, demonstrated that GC-derived exosomal miR-196a-5p directly induces MMT in peritoneal mesothelial cells (HMrSV5) and contributed to the formation of metastatic tumors. Mechanistically, miR-196a-5p binds the 3'-untranslated region (UTR) of F-box protein 45 (FBXO45), an E3 ubiquitin ligase, suppressing its expression and thereby stabilizing snail family transcriptional repressor 1 (Snai1)-a key transcription factor in epithelial-mesenchymal transition (EMT). RNA immunoprecipitation sequencing (RIP seq), dual-luciferase reporter assays, co-immunoprecipitation (CO-IP), and rescue experiments validated the miR-196a-5p/FBXO45/Snai1 axis. Notably, miR-196a-5p disrupts FBXO45-mediated Snai1 ubiquitination and degradation, promoting MMT-driven peritoneal niche remodeling and metastatic progression. These findings reveal a novel exosome-mediated mechanism underlying GC dissemination and highlight miR-196a-5p and FBXO45 as promising therapeutic targets for PM. Show less

Large-for-gestational-age (LGA) neonates have increased risk of adverse pregnancy outcomes and adult metabolic diseases. We aimed to investigate the relationship between plasma angiopoietin-like protein 4 (ANGPTL4), a protein involved in lipid and glucose metabolism during pregnancy, placental function, growth factors, and the risk of LGA. We conducted a prospective cohort study and recruited women with singleton pregnancies at the National Taiwan University Hospital between 2013 and 2018. First trimester maternal plasma ANGPTL4 concentrations were measured. Among 353 pregnant women recruited, the LGA group had higher first trimester plasma ANGPTL4 concentrations than the appropriate-for-gestational-age group. Plasma ANGPTL4 was associated with hemoglobin A1c, post-load plasma glucose, plasma triglyceride, plasma free fatty acid concentrations, plasma growth hormone variant (GH-V), and birth weight, but was not associated with cord blood growth factors. After adjusting for age, body mass index, hemoglobin A1c, and plasma triglyceride concentrations, plasma ANGPTL4 concentrations were significantly associated with LGA risk, and its predictive performance, as measured by the area under the receiver operating characteristic curve, outperformed traditional risk factors for LGA. Plasma ANGPTL4 is associated with glucose and lipid metabolism during pregnancy, plasma GH-V, and birth weight, and is an early biomarker for predicting the risk of LGA. Show less

When plants are subjected to mechanical wounding(MW)caused by insect feeding, extreme weather, and human factors, they rapidly initiate a series of response mechanisms at the transcriptional and metabolic levels, leading to changes in the content of phytohormone and secondary metabolites in plants. In this study, using the medicinal model plant Danshen(Salvia miltiorrhiza) as an example, the effect of MW on the metabolism of medicinal plants was evaluated. By virtue of qRT-PCR and LC-MS, the changes in the biosynthetic genes and contents of jasmonates(JAs) and tanshinones in response to leaf damage stimulation were detected to reveal the related patterns of transcription and metabolism in leaves and roots at different time points after MW treatment, thus exploring the response mechanism of Danshen to MW stress. The results showed that MW induction could transiently increase the expression of biosynthetic genes of Jas, with AOC and JAR beginning to increase and peaking at 2 h after induction, while AOS and OPR3 peaked at 4 h. Correspondingly, the content of OPDA, JA, and JA-Ile all peaked at 2 h. In the biosynthesis of tanshinones, the diterpene synthase genes CPS1 and KSL1 both peaked at 2 h, while the subsequent modification genes CYP450s all peaked at 4 h. The content of the four tanshinones showed a continuous increase trend within 8 h. This study provides a reference for revealing the research on secondary metabolite accumulation under MW stress and lays a foundation for further understanding the role of Jas in enhancing plant resistance, promoting the accumulation of active ingredients, and improving the quality of medicinal materials under MW stress. Show less

Epidermal growth factor receptor (EGFR) over-expression is commonly observed in advanced head and neck squamous cell carcinoma (HNSCC) and is correlated with poor patient outcomes. However, the role of dual-specificity phosphatase 6 (DUSP6) in EGFR-associated HNSCC progression remains poorly understood. This study aimed to investigate the correlation between DUSP6 expression and EGFR signaling in malignant HNSCC tissues. Data mining and in vitro assays were employed to assess DUSP6 expression levels in HNSCC tissues compared to normal tissues. Additionally, the correlation between DUSP6 and EGFR expression was examined. Functional assays were conducted to investigate the modulation of DUSP6 expression by EGFR signaling and its involvement in EGF-induced cell migration and anoikis resistance. Our analysis revealed a significant elevation in DUSP6 expression in HNSCC tissues compared to normal tissues and a strong correlation between DUSP6 and EGFR expression. EGFR signaling modulated DUSP6 expression in a dose- and time-dependent manner, primarily through the extracellular signal-regulated kinase (ERK) pathway. Knockdown experiments demonstrated the functional role of DUSP6 in EGF-induced cell migration and anoikis resistance. The findings of this study elucidate the intricate signaling networks governing DUSP6 expression and its interplay with EGFR signaling in HNSCC. Moreover, the results provide insights into the potential role of DUSP6 as a therapeutic target and highlight the importance of personalized treatment strategies in HNSCC management. Show less

Gut microbiota rearrangement induced by cold temperature is crucial for browning in murine white adipose tissue. This study provides evidence that DUSP6, a host factor, plays a critical role in regulating cold-induced gut microbiota rearrangement. When exposed to cold, the downregulation of intestinal DUSP6 increased the capacity of gut microbiota to produce ursodeoxycholic acid (UDCA). The DUSP6-UDCA axis is essential for driving Lachnospiraceae expansion in the cold microbiota. In mice experiencing cold-room temperature (CR) transitions, prolonged DUSP6 inhibition via the DUSP6 inhibitor (E/Z)-BCI maintained increased cecal UDCA levels and cold-like microbiota networks. By analyzing DUSP6-regulated microbiota dynamics in cold-exposed mice, we identified Marvinbryantia as a genus whose abundance increased in response to cold exposure. When inoculated with human-origin Marvinbryantia formatexigens, germ-free recipient mice exhibited significantly enhanced browning phenotypes in white adipose tissue. Moreover, M. formatexigens secreted the methylated amino acid Nε-methyl-L-lysine, an enriched cecal metabolite in Dusp6 knockout mice that reduces adiposity and ameliorates nonalcoholic steatohepatitis in mice. Our work revealed that host-microbiota coadaptation to cold environments is essential for regulating the browning-promoting gut microbiome. Show less

Most studies for comprehensive molecular profiling of papillary thyroid carcinoma (PTC) have been performed before the 2017 World Health Organization (WHO) classification, in which the diagnostic criteria of follicular variants of PTC have been modified and noninvasive follicular thyroid neoplasm with papillary-like nuclear features has been introduced. This study aims to investigate the shift in the incidence of BRAF V600E mutations in PTCs following the 2017 WHO classification and to further characterize the histologic subtypes and molecular drivers in BRAF-negative cases. The study cohort consisted of 554 consecutive PTCs larger than 0.5 cm between January 2019 and May 2022. Immunohistochemistry for BRAF VE1 was performed for all cases. Compared with a historical cohort of 509 PTCs from November 2013 to April 2018, the incidence of BRAF V600E mutations was significantly higher in the study cohort (86.8% vs 78.8%, P = .0006). Targeted RNA-based next-generation sequencing using a FusionPlex Pan Solid Tumor v2 panel (ArcherDX) was performed for BRAF-negative PTCs from the study cohort. Eight cribriform-morular thyroid carcinomas and 3 cases with suboptimal RNA quality were excluded from next-generation sequencing. A total of 62 BRAF-negative PTCs were successfully sequenced, including 19 classic follicular predominant PTCs, 16 classic PTCs, 14 infiltrative follicular PTCs, 7 encapsulated follicular PTCs, 3 diffuse sclerosing PTCs, 1 tall cell PTC, 1 solid PTC, and 1 diffuse follicular PTC. Among them, RET fusions were identified in 25 cases, NTRK3 fusions in 13 cases, BRAF fusions in 5 cases including a novel TNS1::BRAF fusion, NRAS Q61R mutations in 3 cases, KRAS Q61K mutations in 2 cases, NTRK1 fusions in 2 cases, an ALK fusion in 1 case, an FGFR1 fusion in 1 case, and an HRAS Q61R mutation in 1 case. No genetic variants, from our commercially employed assay, were detected in the remaining 9 cases. In summary, the incidence of BRAF V600E mutations in PTCs significantly increased from 78.8% to 86.8% in our post-2017 WHO classification cohort. RAS mutations accounted for only 1.1% of the cases. Driver gene fusions were identified in 8.5% of PTCs and were clinically relevant given the emerging targeted kinase inhibitor therapy. Of the 1.6% of cases for which no driver alteration was detected, the specificity of drivers tested and tumor classification require further investigation. Show less

Obesity is a global epidemic elevating the risk of various metabolic disorders. As there is a lack of effective drugs to treat obesity, we combined bioinformatics and reverse network pharmacology in this study to identify effective herbs to treat obesity. We identified 1011 differentially expressed genes (DEGs) of adipose tissue after weight loss by analyzing five expression profiles (GSE103766, GSE35411, GSE112307, GSE43471, and GSE35710) from the Gene Expression Omnibus (GEO) database. We identified 27 hub genes from the protein-protein interaction (PPI) network by performing MCODE using the Search Tool for the Retrieval of Interacting Genes (STRING) database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed that these hub genes have roles in the extracellular matrix-receptor interaction, cholesterol metabolism, PI3K-Akt signaling pathway, etc. Ten herbs (Aloe, Portulacae Herba, Mori Follum, Silybum Marianum, Phyllanthi Fructus, Pollen Typhae, Ginkgo Semen, Leonuri Herba, Eriobotryae Folium, and Litseae Fructus) targeting the nine hub genes (COL1A1, MMP2, MMP9, SPP1, DNMT3B, MMP7, CETP, COL1A2, and MUC1) using six ingredients were identified as the key herbs. Quercetin and (-)-epigallocatechin-3-gallate were determined to be the key ingredients. Lastly, Ingredients-Targets, Herbs-Ingredients-Targets, and Herbs-Taste-Meridian Tropism networks were constructed using Cytoscape to elucidate this complex relationship. This study could help identify promising therapeutic targets and drugs to treat obesity. Show less

Soft drusen and subretinal drusenoid deposits (SDDs) characterize two pathways to advanced age-related macular degeneration (AMD), with distinct genetic risks, serum risks, and associated systemic diseases. One hundred and twenty-six subjects with AMD were classified as SDD (with or without soft drusen) or non-SDD (drusen only) by retinal imaging, with serum risks, genetic testing, and histories of cardiovascular disease (CVD) and stroke. There were 62 subjects with SDD and 64 non-SDD subjects, of whom 51 had CVD or stroke. SDD correlated significantly with lower mean serum high-density lipoprotein (61 ± 18 vs. 69 ± 22 mg/dL, P = 0.038, t-test), CVD and stroke (34 of 51 SDD, P = 0.001, chi square), ARMS2 risk allele (P = 0.019, chi square), but not with CFH risk allele (P = 0.66). Non-SDD (drusen only) correlated/trended with APOE2 (P = 0.032) and CETP (P = 0.072) risk alleles (chi square). Multivariate independent risks for SDD were CVD and stroke (P = 0.008) and ARMS2 homozygous risk (P = 0.038). Subjects with subretinal drusenoid deposits and non-SDD subjects have distinct systemic associations and serum and genetic risks. Subretinal drusenoid deposits are associated with CVD and stroke, ARMS2 risk, and lower high-density lipoprotein; non-SDDs are associated with higher high-density lipoprotein, CFH risk, and two lipid risk genes. These and other distinct associations suggest that these lesions are markers for distinct diseases. Show less

Compared with the precise targeting of drug-resistant mutant cancer cells, strategies for eliminating non-genetic adaptation-mediated resistance are limited. The pros and cons of the existence of inflammasomes in cancer have been reported. Nevertheless, the dynamic response of inflammasomes to therapies should be addressed. Tumor-derived exosomes were purified by differential ultracentrifugation and validated by nanoparticle tracking analysis and transmission electron microscopy. A proximity ligation assay and interleukin-1β (IL-1β) level were used for detecting activation of NLRP3 inflammasomes. RNA sequencing was used to analyze the exosomal RNAs. We demonstrated that in cancer cells undergoing Snail-induced epithelial-mesenchymal transition (EMT), tumor cells suppress NLRP3 inflammasome activities of tumor-associated macrophages (TAMs) in response to chemotherapy through the delivery of exosomal miR-21. Mechanistically, miR-21 represses This finding reveals the mechanism of EMT-mediated resistance beyond cancer stemness through modulation of post-treatment inflammasome activity. It also highlights the dynamic remodeling of the TME throughout metastatic evolution. Show less

Homo- or heterodimerization of G protein-coupled receptors (GPCRs) generally alters the normal functioning of these receptors and mediates their responses to a variety of physiological stimuli in vivo. It is well known that melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R) are key regulators of appetite and energy homeostasis in the central nervous system (CNS). However, the GPCR partners of MC3R and MC4R are not well understood. Our objective is to analyze single cell RNA-seq datasets of the hypothalamus to explore and identify novel GPCR partners of MC3R and MC4R and examine the pharmacological effect on the downstream signal transduction and membrane translocation of melanocortin receptors. We conducted an integrative analysis of multiple single cell RNA-seq datasets to reveal the expression pattern and correlation of GPCR families in the mouse hypothalamus. The emerging GPCRs with important metabolic functions were selected for cloning and co-immunoprecipitation validation. The positive GPCR partners were then tested for the pharmacological activation, competitive binding assay and surface translocation ELISA experiments. Based on the expression pattern of GPCRs and their function enrichment results, we narrowed down the range of potential GPCR interaction with MC3R and MC4R for further confirmation. Co-immunoprecipitation assay verified 23 and 32 novel GPCR partners that interacted with MC3R and MC4R in vitro. The presence of these GPCR partners exhibited different effects in the physiological regulation and signal transduction of MC3R and MC4R. This work represented the first large-scale screen for the functional GPCR complex of central melanocortin receptors and defined a composite metabolic regulatory GPCR network of the hypothalamic nucleuses. Show less

Melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R), two neural G protein-coupled receptors are known to be functionally critical for energy balance in vertebrates. As allosteric regulators of melanocortin receptors, melanocortin accessory proteins (MRAPs) are also involved in energy homeostasis. The interaction of MRAPs and melanocortin signaling was previously shown in mammals and zebrafish, but nothing had been reported in amphibians. As the basal class of tetrapods, amphibians occupy a phylogenetic transition between teleosts and terrestrial animals. Here we examined the evolutionary conservation of MC3R, MC4R, and MRAPs between diploid Xenopus tropicalis (xt-) and other chordates and investigated the pharmacological regulatory properties of MRAPs on the neural MC3R and MC4R signaling. Our results showed that xtMRAP and xtMRAP2 both exerted robust potentiation effect on agonist (α-MSH and adrenocorticotropin [ACTH]) induced activation and modulated the basal activity and cell surface translocation of xtMC3R and xtMC4R. In addition, the presence of two accessory proteins could convert xtMC3R and xtMC4R into ACTH-preferred receptors. These findings suggest that the presence of MRAPs exhibits fine control over the pharmacological activities of the neuronal MC3R and MC4R signaling in the Xenopus tropicalis, which is physiologically relevant with the complicated transition of feeding behaviors during their life history. Show less

Hypertriglyceridemia has emerged as a critical coronary artery disease (CAD) risk factor. Rare loss-of-function (LoF) variants in apolipoprotein C-III have been reported to reduce triglycerides (TG) and are cardioprotective in American Indians and Europeans. However, there is a lack of data in other Europeans and non-Europeans. Also, whether genetically increased plasma TG due to ApoC-III is causally associated with increased CAD risk is still unclear and inconsistent. The objectives of this study were to verify the cardioprotective role of earlier reported six LoF variants of APOC3 in South Asians and other multi-ethnic cohorts and to evaluate the causal association of TG raising common variants for increasing CAD risk. We performed gene-centric and Mendelian randomization analyses and evaluated the role of genetic variation encompassing APOC3 for affecting circulating TG and the risk for developing CAD. One rare LoF variant (rs138326449) with a 37% reduction in TG was associated with lowered risk for CAD in Europeans (p = 0.007), but we could not confirm this association in Asian Indians (p = 0.641). Our data could not validate the cardioprotective role of other five LoF variants analysed. A common variant rs5128 in the APOC3 was strongly associated with elevated TG levels showing a p-value 2.8 × 10 Our results highlight the challenges of inclusion of rare variant information in clinical risk assessment and the generalizability of implementation of ApoC-III inhibition for treating atherosclerotic disease. More studies would be needed to confirm whether genetically raised TG and ApoC-III concentrations would increase CAD risk. Show less

Nickel (Ni), which is a carcinogenic workplace hazard, increases the risk of lung cancer. Angiopoietin-like protein 4 (ANGPTL4) is a multifunctional cytokine that is involved in both angiogenesis and metastasis, but its role in lung cancer is still not clear. In this study, we assessed the role of ANGPTL4 in lung carcinogenesis under nickel exposure and investigated the effects of the antidiabetic drug metformin on ANGPTL4 expression and lung cancer chemoprevention. Our results showed that ANGPTL4 is increased in NiCl Show less

Cholesterol metabolism and transport has been a major focus in cardiovascular disease risk modification over the past several decades. Hydroxymethylglutaryl-CoA reductase inhibitors (statins) have been the most commonly used agents, with the greatest benefit in reducing both the primary and secondary risks of cardiovascular disease. However, heart disease remains the leading cause of death in both men and women in the United States. Further investigation and intervention are required to further reduce the risk for cardiovascular disease and cardiovascular-related deaths. This review will focus on high-density lipoprotein metabolism and transport, looking particularly at cholesteryl ester transfer protein (CETP) inhibitors. While studies of the other CETP inhibitors in its class have not shown a significant improvement in the prevention of primary or secondary cardiovascular risk, anacetrapib, the fourth and latest of the CETP inhibitors to be investigated, may be more promising. Show less

Recent genome-wide association studies (GWAS) have identified 97 body-mass index (BMI) associated loci. We aimed to evaluate if dietary intake modifies BMI associations at these loci in the Singapore Chinese population. We utilized GWAS information from six data subsets from two adult Chinese population (N = 7817). Seventy-eight genotyped or imputed index BMI single nucleotide polymorphisms (SNPs) that passed quality control procedures were available in all datasets. Alternative Healthy Eating Index (AHEI)-2010 score and ten nutrient variables were evaluated. Linear regression analyses between z score transformed BMI (Z-BMI) and dietary factors were performed. Interaction analyses were performed by introducing the interaction term (diet x SNP) in the same regression model. Analysis was carried out in each cohort individually and subsequently meta-analyzed using the inverse-variance weighted method. Analyses were also evaluated with a weighted gene-risk score (wGRS) contructed by BMI index SNPs from recent large-scale GWAS studies. Nominal associations between Z-BMI and AHEI-2010 and some dietary factors were identified (P = 0.047-0.010). The BMI wGRS was robustly associated with Z-BMI (P = 1.55 × 10 The CCDC171 gene locus may interact with cholesterol intake to increase BMI in the Singaporean Chinese population, however most known obesity risk loci were not associated with dietary intake and did not interact with diet to modify BMI levels. Show less

Recent genome-wide association studies (GWAS) have identified multiple loci associated with coronary artery disease (CAD) among predominantly Europeans. However, their relevance to multi-ethnic populations from Southeast Asia is largely unknown. We performed a meta-analysis of four GWAS comprising three Chinese studies and one Malay study (Total N = 2,169 CAD cases and 7,376 controls). Top hits (P < 5 × 10 Show less

Disturbance in lipid metabolism has been suggested as a major pathogenic factor for age-related macular degeneration (AMD). Conventional lipid measures have been inconsistently associated with AMD. Other factors that can alter lipid metabolism include lipoprotein phenotype and genetic mutations. We performed a case-control study to examine the association between lipoprotein profile and neovascular AMD (nAMD) and whether the cholesterylester transfer protein ( Show less

Genome-wide association studies (GWAS) on Parkinson's disease (PD) have mostly been done in Europeans and Japanese. No study has been done in Han Chinese, which make up nearly a fifth of the world population. We conducted the first Han Chinese GWAS analysing a total of 22,729 subjects (5,125 PD cases and 17,604 controls) from Singapore, Hong Kong, Malaysia, Korea, mainland China and Taiwan. We performed imputation, merging and logistic regression analyses of 2,402,394 SNPs passing quality control filters in 779 PD cases, 13,227 controls, adjusted for the first three principal components. 90 SNPs with association P < 10-4 were validated in 9 additional sample collections and the results were combined using fixed-effects inverse-variance meta-analysis. We observed strong associations reaching genome-wide significance at SNCA, LRRK2 and MCCC1, confirming their important roles in both European and Asian PD. We also identified significant (P < 0.05) associations at 5 loci (DLG2, SIPA1L2, STK39, VPS13C and RIT2), and observed the same direction of associations at 9 other loci including BST1 and PARK16. Allelic heterogeneity was observed at LRRK2 while European risk SNPs at 6 other loci including MAPT and GBA-SYT11 were non-polymorphic or very rare in our cohort. Overall, we replicate associations at SNCA, LRRK2, MCCC1 and 14 other European PD loci but did not identify Asian-specific loci with large effects (OR > 1.45) on PD risk. Our results also demonstrate some differences in the genetic contribution to PD between Europeans and Asians. Further pan-ethnic meta-analysis with European GWAS cohorts may unravel new PD loci. Show less

Throughout life, stem cells in the ventricular-subventricular zone generate neuroblasts that migrate via the rostral migratory stream (RMS) to the olfactory bulb, where they differentiate into local interneurons. Although progress has been made toward identifying extracellular factors that guide the migration of these cells, little is known about the intracellular mechanisms that govern the dynamic reshaping of the neuroblasts' morphology required for their migration along the RMS. In this study, we identify DOCK7, a member of the DOCK180-family, as a molecule essential for tangential neuroblast migration in the postnatal mouse forebrain. DOCK7 regulates the migration of these cells by controlling both leading process (LP) extension and somal translocation via distinct pathways. It controls LP stability/growth via a Rac-dependent pathway, likely by modulating microtubule networks while also regulating F-actin remodeling at the cell rear to promote somal translocation via a previously unrecognized myosin phosphatase-RhoA-interacting protein-dependent pathway. The coordinated action of both pathways is required to ensure efficient neuroblast migration along the RMS. Show less

Pyrrolizidine alkaloids (PAs) are a group of phytotoxins that can induce human liver injury, particularly hepatic sinusoidal obstruction syndrome (HSOS). To date, the molecular targets of PA-induced HSOS are largely unknown. In this study, retrorsine (RTS), a known hepatotoxic PA, was used as a representative PA for proteomic studies. Toxicological assessment demonstrated that 35 mg/kg RTS (designated as RTS-L) caused early lesions of HSOS at 24 h after dosing. A proteomic approach revealed 17 up-regulated and 31 down-regulated proteins in RTS-L-treated rats. Subsequently, bioinformatic analysis suggested that two proteins, carbamoyl-phosphate synthase (CPS1) (p < 0.05) and ATP synthase subunit beta (ATP5B) (p < 0.01) were associated with RTS-L intoxication. Using immunohistochemical staining, we further verified the down-regulation of CPS1 and ATP5B in RTS-L-treated rats. These findings indicated that CPS1 and ATP5B were altered in the RTS-induced early lesions of HSOS in rats, and therefore, these two proteins and their involved pathways might play important roles in the initiation of HSOS. To the best of our knowledge, our study using a proteomic approach combined with conventional toxicological assessment is the first systems toxicology study on PA-induced HSOS. The results of this study provide novel findings on protein profiles in response to PA exposure, which can serve as a starting point to further investigate potential protein targets and their interactions with PAs to induce HSOS. Show less

Polyunsaturated fatty acids (PUFAs) have a major impact on human health. Recent genome-wide association studies (GWAS) have identified several genetic loci that are associated with plasma levels of n-3 and n-6 PUFAs in primarily subjects of European ancestry. However, the relevance of these findings has not been evaluated extensively in other ethnic groups. The primary aim of this study was to evaluate for genetic loci associated with n-3 and n-6 PUFAs and to validate the role of recently identified index loci using data from a Singaporean Chinese population. Using a GWAS approach, we evaluated associations with plasma concentrations of three n-3 PUFAs [alphalinolenic acid (ALA), eicosapentaenoic acid and docosahexaenoic acid], four n-6 PUFAs [linoleic acid (LA), gammalinolenic acid, dihomogammalinolenic acid (DGLA) and arachidonic acid], and estimates of delta-5 desaturase and delta-6 desaturase activities among the participants (N = 1361) of the Singaporean Chinese Health Study. Our results reveal robust genome-wide associations (p value <5 × 10(-8)) with ALA, all four n-6 PUFAs, and delta-6 desaturase activity at the FADS1/FADS2 locus. We further replicated the associations between common index variants at the NTAN1/PDXDC1 locus and n-6 PUFAs LA and DGLA, and between the JMJD1C locus and n-6 PUFA LA (p value between 0.0490 and 9.88 × 10(-4)). These associations were independent of dietary intake of PUFAs. In aggregate, we show that genetic loci that influence plasma concentrations of n-3 and n-6 PUFAs are shared across different ethnic groups. Show less

Chandelier cells (ChCs), typified by their unique axonal morphology, are the most distinct interneurons present in cortical circuits. Via their distinctive axonal terminals, called cartridges, these cells selectively target the axon initial segment of pyramidal cells and control action potential initiation; however, the mechanisms that govern the characteristic ChC axonal structure have remained elusive. Here, by employing an in utero electroporation-based method that enables genetic labeling and manipulation of ChCs in vivo, we identify DOCK7, a member of the DOCK180 family, as a molecule essential for ChC cartridge and bouton development. Furthermore, we present evidence that DOCK7 functions as a cytoplasmic activator of the schizophrenia-associated ErbB4 receptor tyrosine kinase and that DOCK7 modulates ErbB4 activity to control ChC cartridge and bouton development. Thus, our findings define DOCK7 and ErbB4 as key components of a pathway that controls the morphological differentiation of ChCs, with implications for the pathogenesis of schizophrenia. Show less