IL-6 Up-Regulates Expression of LIM-Domain Only Protein 4 in Psoriatic Keratinocytes through Activation of the MEK/ERK/NF-κB Pathway.

Psoriasis is a chronic inflammatory skin disease characterized by the activation of keratinocytes and the infiltration of immune cells. Overexpression of the transcription factor LIM-domain only protein 4 (LMO4) promoted by IL-23 has critical roles in regulating the proliferation and differentiation of psoriatic keratinocytes. IL-6, an autocrine cytokine in psoriatic epidermis, is a key mediator of IL-23/T helper 17-driven cutaneous inflammation. However, little is known about how IL-6 regulates the up-regulation of LMO4 expression in psoriatic lesions. In this study, human immortalized keratinocyte cells, clinical biopsy specimens, and an animal model of psoriasis induced by imiquimod cream were used to investigate the role of IL-6 in the regulation of keratinocyte proliferation and differentiation. Psoriatic epidermis showed abnormal expression of IL-6 and LMO4. IL-6 up-regulated the expression of LMO4 and promoted keratinocyte proliferation and differentiation. Furthermore, in vitro and in vivo studies showed that IL-6 up-regulates LMO4 expression by activating the mitogen-activated extracellular signal-regulated kinase (MEK)/extracellular signal-regulated kinase (ERK)/NF-κB signaling pathway. These results suggest that IL-6 can activate the NF-κB signaling pathway, up-regulate the expression of LMO4, lead to abnormal proliferation and differentiation of keratinocytes, and promote the occurrence and development of psoriasis.

Mitotic spindle disassembly in human cells relies on CRIPT having hierarchical redox signals.

Swift and complete spindle disassembly in late mitosis is essential for cell survival, yet how it happens is largely unknown in mammalian cells. Here we used real-time live cell microscopy and biochemical assays to show that the primordial dwarfism (PD)-related cysteine-rich protein CRIPT dictates the spindle disassembly in a redox-dependent manner in human cells. This previously reported cytoplasmic protein was found to have a confined nuclear localization with a nucleolar concentration during interphase but was distributed to spindles and underwent redox modifications to form disulfide bonds in CXXC pairs during mitosis. Then, it directly interacted with, and might transfer a redox response to, tubulin subunits via a putative redox exchange among cysteine residues to induce microtubule depolymerization. Expression of CRIPT proteins with mutations of these cysteine residues blocked spindle disassembly, generating two cell types with long-lasting metaphase spindles or spindle remnants. Live-cell recordings of a disease-relevant mutant (CRIPTC3Y) revealed that microtubule depolymerization at spindle ends during anaphase and the entire spindle dissolution during telophase might share a common CRIPT-bearing redox-controlled mechanism.

Ebselen improves lipid metabolism by activating PI3K/Akt and inhibiting TLR4/JNK signaling pathway to alleviate nonalcoholic fatty liver.

Nonalcoholic fatty liver disease (NAFLD), a metabolic disease associated with obesity and type 2 diabetes. Due to its complex pathogenesis, there are still limitations in the knowledge of the disease. To date, no drug has been approved to treat NAFLD. This study aims to explore the role and mechanism of Ebselen (EbSe) in NAFLD. A high-fat diet-induced mouse model of NAFLD was employed to investigate EbSe function in NAFLD mice by EbSe gavage and to regularly monitor the mouse body weight. HE and oil red O staining were performed, respectively, to detect the pathological damage and lipid accumulation in mouse liver tissues. The biochemical and ELISA kits were employed to measure the levels of ALT, AST, TG, TC, LDL-C, HDL-C and pro-inflammatory cytokines within mouse serum or liver tissue. The expression of key proteins of PPARα, fatty acid ß oxidation-related protein, PI3K/Akt and TLR4/JNK signaling pathway was detected by western blot. EbSe significantly downregulated body weight, liver weight and liver lipid accumulation in NAFLD mice and downregulated ALT, AST, TG, TC, LDL-C and increased HDL-C serum levels. EbSe upregulated the expression levels of PPARα and fatty acid ß oxidation-associated proteins CPT1α, ACOX1, UCP2 and PGC1α. EbSe promoted Akt and PI3K phosphorylation, and inhibited TLR4 expression and JNK phosphorylation. EbSe can upregulate PPARα to promote fatty acid ß-oxidation and improve hepatic lipid metabolism. Meanwhile, EbSe also activated PI3K/Akt and inhibited TLR4/JNK signaling pathway. EbSe is predicted to be an effective therapeutic drug for treating NAFLD.

Comprehensive Map of the Artemisia annua Proteome and Quantification of Differential Protein Expression in Chemotypes Producing High versus Low Content of Artemisinin.

Artemisia annua is well known for biosynthesizing the antimalarial drug artemisinin. Here, a global proteomic profiling of A. annua is conducted with identification of a total of 13 403 proteins based on the genome sequence annotation database. Furthermore, a spectral library is generated to perform quantitative proteomic analysis using data independent acquisition mass spectrometry. Specifically, proteins between two chemotypes that produce high (HAP) and low (LAP) artemisinin content, respectively, are comprehensively quantified and compared. 182 proteins are identified with abundance significantly different between these two chemotypes means after the statistic use the p-value and fold change it is found 182 proteins can reach the demand conditions which represent the expression are significantly different between the high artemisnin content plants (HAPs) and the low artemisnin content plants (LAPs). Data are available via ProteomeXchange with identifier PXD015547. Overall, this current study globally identifies the proteome of A. annua and quantitatively compares the targeted sub-proteomes between the two cultivars of HAP and LAP, providing systematic information on metabolic pathways of A. annua.

Differential gene regulatory plasticity between upper and lower layer cortical excitatory neurons.

Neocortical projection neurons consist of intracortical connected upper layer (UL, layer II-IV) neurons and subcortical connected lower layer (LL, layer V-VI) neurons. Afferent activity from the thalamus regulates layer-specific gene expression during postnatal development, which is critical for the formation of proper neocortical cytoarchitecture. Here, we show that activity-dependent gene regulation is confined to UL cortical neurons, but not LL neurons, and that this distinction is likely due to epigenetic modifications of chromatin. We found that the immediate early genes (IEGs), EGR1 and c-FOS, are downregulated in all cortical laminar layers in the absence of afferent activity in vivo. Transcriptional assays demonstrated that EGR1 and c-FOS are able to bind to the promoters of UL- and LL-specific genes to induce transcription. Furthermore, we discovered that LL neurons express higher levels of heterochromatin markers, such as H3K9m3 and H4K20m3, compared to UL neurons. Our results suggest that differential epigenetic modifications of chromatin is an intrinsic mechanism that underlies the different sensitivities of cortical neurons to activity-dependent gene regulation.

Exosomal proteome analysis of human plasma to monitor sepsis progression.

Exosomes are cell-derived vesicles containing RNA, lipid, and protein, which act in body immune response, intercellular signaling and some other important biological processes. Exosomes have been extensively studied in the past several years on their disease related mechanisms and potential roles to monitor disease progression as biomarkers. Compared with analyzing exosome RNA, comprehensive proteome profiling of exosomes in clinical samples (e.g. blood) are highly demanded but limited mainly due to lack of a reproducible method for efficient exosome extraction. In this study, we evaluated and optimized an exosome preparation approach using one-step ultracentrifugation through an Optiprep™ cushion. Exosomes prepared via this method and analyzed by mass spectrometry using Q-Exactive plus, has led to reproducible identification and quantification of 200 + proteins from human plasma samples of as little as 300 µL. Therefore, such a straightforward exosome extract method has enable us to deeply profile exosome proteomes from human blood at a scale of clinical studies. As a proof of principal, we practiced this approach in analyzing the exosome proteomic profiles of blood samples collected from a sepsis patient during six time points after diagnosis. Among the 238 proteins identified and quantified across the 6 samples, protein SPTLC3 involved in the sphingolipid metabolism, shows a negative correlation (p = 0.02, correlation coefficient = -0.984) with disease progression indicated by body temperature (BD) and C-reactive protein (CRP). Therefore, SPTLC3 could be an interesting target for future study on molecular mechanism of sepsis development, as well as potential classifier to monitor clinical progression of sepsis.

[Gene characterization of the VP1 region of Coxsackievirus A4 from herpangina cases in Shenzhen of China].

OBJECTIVE: To analyze the phylogeny of the VP1 region of Coxsackie virus A4 (CVA4) from herpangina cases of Shenzhen in 2012 and 2014. METHODS: Real-time reverse transcription(RT)-PCR method was used to test virus such as human enterovirus71, coxsackievirus A16, coxsackievirus A4, coxsackievirus A6 and coxsackievirus A10. The VP1 gene of CVA4 positive samples were amplified by RT-PCR and sequenced. Then the homology and phylogeny analysis of the CVA4 VP1 region was performed. RESULTS: The six CVA4 isolates identified in the herpangina cases during 2012 and 2014 were mostly closed with GIb genotypes. The nucleotide and amino acid homology between them were 94.1% (nucleotide mutation rate was 5.9%) and 98.3%, five amino acid mutation were found in CVA4 strain 2014 of Shenzhen: aa22N-S, aa34T-A, aa63N-S, aa165A-D, aa200T-A. The phylogenetic analysis based on VP1 region demonstrates that CVA4 strain of Shenzhen in 2012 had the nearest genetic relationship with CVA4 strain of Shandong isolated in 2010 (KF150144). However, CVA4 strain of Shenzhen in 2014 had the nearest genetic relationship with CVA4 strain of Jilin (JQ715709) isolated in 2006. CONCLUSIONS: It reveals that all CVA4 strains from the two outbreak of herpangina belong to genotype GIb, the degree of variation in VP1 region of CVA4 strain of Shenzhen in 2014 is obvious compared with that in 2012.There is an obvious difference on internal trend of evolution lineage between the CVA4 strains from 2012 and 2014.

KCC2 interacts with the dendritic cytoskeleton to promote spine development.

The neuron-specific K-Cl cotransporter, KCC2, induces a developmental shift to render GABAergic transmission from depolarizing to hyperpolarizing. Now we demonstrate that KCC2, independently of its Cl(-) transport function, is a key factor in the maturation of dendritic spines. This morphogenic role of KCC2 in the development of excitatory synapses is mediated by structural interactions between KCC2 and the spine cytoskeleton. Here, the binding of KCC2 C-terminal domain to the cytoskeleton-associated protein 4.1N may play an important role. A more general conclusion based on our data is that KCC2 acts as a synchronizing factor in the functional development of glutamatergic and GABAergic synapses in cortical neurons and networks.

Data independent acquisition-mass spectrometry (DIA-MS)-based comprehensive profiling of bone metastatic cancers revealed molecular fingerprints to assist clinical classifications for bone metastasis of unknown primary (BMUP).

BACKGROUND: Bone metastasis is the third most common metastatic cancers worldwide. It is a group of highly heterogeneous diseases with various potential cancer primaries. Among them, one third was diagnosed as bone metastasis of unknown primary (BMUP) due to lack of indication for the primary tumor even after comprehensive examinations. Thus, the prognosis of BMUP is often very poor since the treatment was largely empirical and untargeted. To assist identification of the primary tumor, a series of molecular markers including traditional tissue-specific histochemistry as well as gene and mRNA markers were developed with moderate to good sensitivity and specificity. METHODS: In this paper, we carried out a comprehensive expression profiling for fresh-frozen tissue samples of bone metastasis from lung, prostate and liver cancers using high resolution, data-independent-acquisition mass spectrometry (DIA-MS). The proteome variation was analyzed and protein classifiers were prioritized. RESULTS: Over 6,000 proteins were quantified from 18 samples, which, to the best of our knowledge, was never achieved before. Further statistical analysis and bioinformatics data mining revealed 4 significant proteins (RFIP1, CK15, ESYT2, and MAL2) with excellent discriminating capabilities with AUCs higher than 0.8. CONCLUSIONS: The comprehensive proteome map of bone metastases will complement available genomic and transcriptomic data. Newly discovered protein classifiers will expand current diagnostic arsenal for tissue of origin studies in BMUP. Furthermore, the proteome map generated in this study by DIA-MS allows future data re-mining as our knowledge advances to assist investigation of bone metastasis and progression of tumors as well as the development of diagnostic tools and prognosis management for BMUPs.

Clinical characteristics of older and younger patients infected with SARS-CoV-2.

BACKGROUND: SARS-CoV-2 causes high mortality risk in older patients. This study aims to characterize the clinical features of older and younger SARS-CoV-2 infected patients. RESULTS: A total of 239 patients were divided into the younger group (<60 years; n=181) and the older group (≥60 years; n=58). In both groups, fever and cough were common symptoms. However, dyspnea was more frequent in older patients than younger patients (20.7% versus 9.9%, p=0.032). Compared with younger patients, older patients harbored more severe cases (37.9% versus 17.1%, p=0.001) and comorbidities (58.6% versus 21.0%, p<0.001) such as hypertension and diabetes. The baseline values of eosinophils and C-reactive protein were abnormal in older and younger groups. From baseline to day 14, significant decreases of three biomarkers (C-reactive protein, hemoglobin, albumin) and dramatic increases of three biomarkers (lymphocytes, platelets, blood urea nitrogen) were observed in older patients. CONCLUSION: Older and younger patients exhibited differences in dyspnea, comorbidities, and proportions of severe cases. Moreover, the disease progression of SARS-CoV-2 in older patients is observed with the dynamics of laboratory biomarkers, supporting their potential use in disease monitoring. METHODS: We retrieved clinical symptoms, laboratory findings, comorbidities, and hospitalization information of SARS-CoV-2 cases in Changsha.

Treatment strategies of hospitalized patients with coronavirus disease-19.

With the outbreak of coronavirus disease-19 (COVID-19), Changsha faced an increasing burden of treating the Wuhan migrants and their infected patients. This study is a retrospective, single-center case series of the 238 consecutive hospitalized patients with confirmed COVID-19 at the First Hospital of Changsha city, China, from 01/21 to 02/14, 2020; the final date of follow-up was 02/27, 2020. Of 238 patients 43.7% visited Wuhan, 58.4% got in touch with Wuhan people, and 47.5% had contacted with diagnosed patients. 37.8% patients had family members infected. 190 cases had mild / general disease, and 48 cases had severe / critical disease. Compared to mild or general patients, more severe or critical patients visited Wuhan (59.6% vs 40.2%; P=0.02) and contacted with Wuhan people (74.5% vs 55.0%; P=0.02). All patients received antiviral treatment, including Lopinavir / Ritonavir (29.3%), Interferon (14.6%) and their combination (40.6%), Arbidol (6.7%), Xuebijing (7.1%) and Chloroquine phosphate (1.3%). Severe and critical patients received glucocorticoid, Gamma-globulin and oxygen inhalation. Some received mechanic ventilation support. As of 02/27, 161 patients discharged. The median length of hospital stay was 13 days. The 10-, 14-, 20- and 28-day discharge rate was 19.1%, 42.8%, 65.0% and 76.4%, respectively. No hospital-related transmission was observed.

SARS-CoV-2 clearance in COVID-19 patients with Novaferon treatment: A randomized, open-label, parallel-group trial.

BACKGROUND: The antiviral effects of Novaferon, a potent antiviral protein drug, on COVID-19 was evaluated in the laboratory, and in a randomized, open-label, parallel-group trial. METHODS: In the laboratory, Novaferon's inhibition of viral replication in cells infected with SARS-CoV-2, and prevention of SARS-CoV-2 entry into healthy cells was determined. Antiviral effects of Novaferon in COVID-19 patients with treatment of Novaferon, Novaferon plus Lopinavir/Ritonavir, or Lopinavir/Ritonavir were evaluated. The primary endpoint was the SARS-CoV-2 clearance rates on day six of treatment, and the secondary endpoint was the time to SARS-CoV-2 clearance. RESULTS: Novaferon inhibited viral replication (EC50=1.02ng/ml), and prevented viral infection (EC50=0.10ng/ml). Results from the 89 enrolled COVID-19 patients showed that both Novaferon and Novaferon plus Lopinavir/Ritonavir groups had significantly higher viral clearance rates on day six than Lopinavir/Ritonavir group (50.0% vs. 24.1%, p=0.0400, and 60.0% vs. 24.1%, p=0.0053). The median time to viral clearance was six days, six days, and nine days for three groups, respectively, a 3-day reduction in both the Novaferon and Novaferon plus Lopinavir/Ritonavir groups compared with the Lopinavir/Ritonavir group. CONCLUSIONS: Novaferon exhibited anti-SARS-CoV-2 effects in vitro and in COVID-19 patients. These data justify further evaluation of Novaferon. TRIAL REGISTRATION NUMBER: Number ChiCTR2000029496 at the Chinese Clinical Trial Registry (http://www.chictr.org.cn/).

In-Depth Characterization of Mass Spectrometry-Based Proteomic Profiles Revealed Novel Signature Proteins Associated with Liver Metastatic Colorectal Cancers.

Liver metastasis is the most common form of metastatic colorectal cancers during the course of the disease. The global change in protein abundance in liver metastatic colorectal cancers and its role in metastasis establishment have not been comprehensively analyzed. In the present study, fresh-frozen tissue samples including normal colon/localized/liver metastatic CRCs from each recruited patient were analyzed by quantitative proteomics using a multiplexed TMT labeling strategy. Around 5000 protein groups were quantified from all samples. The proteomic profile of localized/metastatic CRCs varied greatly from that of normal colon tissues; differential proteins were mainly from extracellular regions and participate in immune activities, which is crucial for the chronic inflammation signaling pathways in the tumor microenvironment. Further statistical analysis revealed 47 proteins exhibiting statistical significance between localized and metastatic CRCs, of which FILI1P1 and PLG were identified for the first time in proteomic data, which were highly associated with liver metastasis in CRCs.

Isoform-specific early trafficking of AMPA receptor flip and flop variants.

Flip and flop splice variants of AMPA receptor subunits are expressed in distinct but partly overlapping patterns and impart different desensitization kinetics to cognate receptor channels. In the absence of specific antibodies, isoform-specific differences in trafficking or localization of native flip and flop subunits remain uncharacterized. We report that in several transfected cell lines, transport of homomeric glutamate receptor (GluR)-D(flop) receptors is largely blocked at the endoplasmic reticulum (ER) exit, whereas GluR-D(flip) undergoes complex glycosylation and reaches the plasma membrane at >10x higher levels than GluR-D(flop), as determined by immunofluorescence, patch-clamp recordings and biochemical assays. The transport difference between flip and flop is independent of activity, is primarily determined by amino acid residue 780 (Leu in flop, Val in flip), and is manifested even in the secretion of the soluble ligand-binding domain, suggesting it is independent of oligomerization. Coexpression with stargazin or with the flip isoform rescues the surface expression of GluR-D(flop) near to the level exhibited by GluR-D(flip). Our results demonstrate that the extracellular flip/flop region, via interactions with ER luminal splice form-specific protein(s), plays a hitherto unappreciated and important role in AMPA-receptor trafficking.

Optical detection of plasma chitotriosidase activity in healthy Chinese children using fluorescence spectrophotometry.

BACKGROUND: Plasma chitotriosidase had been proposed as a biochemical marker of macrophage accumulation in several lysosomal storage disorders. The selection of wavelength and possible interferences and errors have not yet been explored in the assay of chitotriosidase activity. We evaluated the feasibility of measurement of plasma chitotriosidase activity by fluorescence spectrophotometry and established pediatric reference values for earlier diagnosis of related diseases. METHODS: We assayed plasma chitotriosidase activity in 104 healthy Chinese children by a fluorometric approach which combines 3-dimension scan spectra, wavelength scan spectra, time scan spectra and fluorescence intensity analysis. RESULTS: The optimal excitation wavelength and emission wavelength were 358 and 448 nm, respectively. A change of enzyme activity over time was observed fluorometrically, The reference value was 13.04+/-4.94 nmol/ml/h (12.45+/-4.37 nmol/ml/h for boys and 14.04+/-3.99 nmol/ml/h for girls). CONCLUSIONS: We present an integrated application of the fluorescence spectrophotometry as an ideal tool to determine enzymatic activity with 4-methylumbelliferyl triacetylchitotrioside as labeled substrates in clinical laboratory. The function of 3D scan was proved powerful in determination of plasma chitotriosidase activity. The establishment of plasma chitotriosidase activity reference pediatric values was potentially useful for the evaluation of all related diseases.

Detection and characterization of three zoonotic viruses in wild rodents and shrews from Shenzhen city, China.

Diverse species of rodents and shrews, which are abundant worldwide, harbor a variety of viruses; some of these are closely related to human viruses and possess zoonotic potential. Previously studies have demonstrated that the mammarenavirus and hantavirus carried by rodents or shrews could cause diseases in human population. To determine the distribution of zoonotic viruses in Shenzhen city, the major city in southern China with a high population density, we analyzed 225 rodents (Rattus norvegicus and Rattus flavipectus) and 196 shrews (Suncus murinus) from urban and rural districts for the presence of mammarenavirus, hantavirus, and hepatitis E virus (HEV) by RT-PCR targeting the conserved regions. The infection rates for mammarenavirus, hantaviruses, and HEV in rodents and shrews were 3.56%, 6.89%, and 1.66%, respectively. Partial genome fragment analysis indicated that mammarenavirus and hantavirus strains had more than 90% and 99% nucleic acid identity with Cardamones virus and Seoul virus, respectively, which cause diseases in humans. Although the present HEV strains identified are typically found worldwide, phylogenetic analysis demonstrated a divergence of 16%. To our knowledge, the present work is the first report of the prevalence of mammarenavirus, hantaviruses, and rat HEV strains in rodents and shrews from Shenzhen city, China. Our findings highlight the zoonotic potential of rodent- and shrew-borne mammarenavirus and hantavirus, and the biodiversity of rat HEV isolates in Shenzhen city. The present work suggests that utilization of good hygiene habits is important to minimize the risk of zoonosis.

Molecular mechanisms controlling synaptic recruitment of GluA4 subunit-containing AMPA-receptors critical for functional maturation of CA1 glutamatergic synapses.

Synaptic recruitment of AMPA receptors (AMPARs) represents a key postsynaptic mechanism driving functional development and maturation of glutamatergic synapses. At immature hippocampal synapses, PKA-driven synaptic insertion of GluA4 is the predominant mechanism for synaptic reinforcement. However, the physiological significance and molecular determinants of this developmentally restricted form of plasticity are not known. Here we show that PKA activation leads to insertion of GluA4 to synaptic sites with initially weak or silent AMPAR-mediated transmission. This effect depends on a novel mechanism involving the extreme C-terminal end of GluA4, which interacts with the membrane proximal region of the C-terminal domain to control GluA4 trafficking. In the absence of GluA4, strengthening of AMPAR-mediated transmission during postnatal development was significantly delayed. These data suggest that the GluA4-mediated activation of silent synapses is a critical mechanism facilitating the functional maturation of glutamatergic circuitry during the critical period of experience-dependent fine-tuning. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'.

Crystal structure of the second PDZ domain of SAP97 in complex with a GluR-A C-terminal peptide.

Synaptic targeting of GluR-A subunit-containing glutamate receptors involves an interaction with synapse-associated protein 97 (SAP97). The C-terminus of GluR-A, which contains a class I PDZ ligand motif (-x-Ser/Thr-x-phi-COOH where phi is an aliphatic amino acid) associates preferentially with the second PDZ domain of SAP97 (SAP97(PDZ2)). To understand the structural basis of this interaction, we have determined the crystal structures of wild-type and a SAP97(PDZ2) variant in complex with an 18-mer C-terminal peptide (residues 890-907) of GluR-A and of two variant PDZ2 domains in unliganded state at 1.8-2.44 A resolutions. SAP97(PDZ2) folds to a compact globular domain comprising six beta-strands and two alpha-helices, a typical architecture for PDZ domains. In the structure of the peptide complex, only the last four C-terminal residues of the GluR-A are visible, and align as an antiparallel beta-strand in the binding groove of SAP97(PDZ2). The free carboxylate group and the aliphatic side chain of the C-terminal leucine (Leu907), and the hydroxyl group of Thr905 of the GluR-A peptide are engaged in essential class I PDZ interactions. Comparison between the free and complexed structures reveals conformational changes which take place upon peptide binding. The betaAlpha-betaBeta loop moves away from the C-terminal end of alphaB leading to a slight opening of the binding groove, which may better accommodate the peptide ligand. The two conformational states are stabilized by alternative hydrogen bond and coulombic interactions of Lys324 in betaAlpha-betaBeta loop with Asp396 or Thr394 in betaBeta. Results of in vitro binding and immunoprecipitation experiments using a PDZ motif-destroying L907A mutation as well as the insertion of an extra alanine residue between the C-terminal Leu907 and the stop codon are also consistent with a 'classical' type I PDZ interaction between SAP97 and GluR-A C-terminus.

Human EAG channels are directly modulated by PIP2 as revealed by electrophysiological and optical interference investigations.

Voltage-gated ether à go-go (EAG) K(+) channels are expressed in various types of cancer cells and also in the central nervous system. Aberrant overactivation of human EAG1 (hEAG1) channels is associated with cancer and neuronal disorders such as Zimmermann-Laband and Temple-Baraitser syndromes. Although hEAG1 channels are recognized as potential therapeutic targets, regulation of their functional properties is only poorly understood. Here, we show that the membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2) is a potent inhibitory gating modifier of hEAG1 channels. PIP2 inhibits the channel activity by directly binding to a short N-terminal segment of the channel important for Ca(2+)/calmodulin (CaM) binding as evidenced by bio-layer interferometry measurements. Conversely, depletion of endogenous PIP2 either by serotonin-induced phospholipase C (PLC) activation or by a rapamycin-induced translocation system enhances the channel activity at physiological membrane potentials, suggesting that PIP2 exerts a tonic inhibitory influence. Our study, combining electrophysiological and direct binding assays, demonstrates that hEAG1 channels are subject to potent inhibitory modulation by multiple phospholipids and suggests that manipulations of the PIP2 signaling pathway may represent a strategy to treat hEAG1 channel-associated diseases.