Sea Anemone Kunitz Peptide HCIQ2c1 Reduces Histamine-, Lipopolysaccharide-, and Carrageenan-Induced Inflammation via the Suppression of Pro-Inflammatory Mediators.

Inflammation is a physiological response of the immune system to infectious agents or tissue injury, which involves a cascade of vascular and cellular events and the activation of biochemical pathways depending on the type of harmful agent and the stimulus generated. The Kunitz peptide HCIQ2c1 of sea anemone is a strong protease inhibitor and exhibits neuroprotective and analgesic activities. In this study, we investigated the anti-inflammatory potential of HCIQ2c1 in histamine- and lipopolysaccharide (LPS)-activated RAW 264.

Extracellular Vesicles from Plasma of Patients with Glioblastoma Promote Invasion of Glioblastoma Cells Even After Tumor Resection.

: Glioblastoma (GB) is a highly aggressive tumor, whose progression is mediated by secretion of extracellular vesicles (EVs), which can pass the brain-blood barrier and be found in the plasma. Here, we performed a comparative analysis of the effects of EVs from the plasma of healthy donors (hEVs) and GB patients before (bEVs) and after (aEVs) tumor surgical resection on invasion of normal astrocytes and GB cells. : We performed the transwell invasion assay, analyzed MAP kinases activation by Western blotting, studied SNAI1/SNAI2 cellular localization by confocal microscopy, measured cadherins expression by flow cytometry, and analyzed secretion of cytokines, which regulate migration and inflammation, by immunoassay.

Toxins from Animal Venom-A Rich Source of Active Compounds with High Pharmacological Potential.

Animal venoms contain a huge variety of bioactive molecules-namely, toxins-with an almost combinatorial spectrum of biological activities [...

Sea Anemone Kunitz Peptide HCIQ2c1: Structure, Modulation of TRPA1 Channel, and Suppression of Nociceptive Reaction In Vivo.

TRPA1 is a homotetrameric non-selective calcium-permeable channel. It contributes to chemical and temperature sensitivity, acute pain sensation, and development of inflammation. HCIQ2c1 is a peptide from the sea anemone that inhibits serine proteases.

Structure and dynamics of the interaction of Delta and Omicron BA.1 SARS-CoV-2 variants with REGN10987 Fab reveal mechanism of antibody action.

Study of mechanisms by which antibodies recognize different viral strains is necessary for the development of new drugs and vaccines to treat COVID-19 and other infections. Here, we report 2.5 Å cryo-EM structure of the SARS-CoV-2 Delta trimeric S-protein in complex with Fab of the recombinant analog of REGN10987 neutralizing antibody.

In Search of the Role of Three-Finger Starfish Proteins.

Three-finger proteins (TFPs), or Ly6/uPAR proteins, are characterized by the beta-structural LU domain containing three protruding "fingers" and stabilized by four conserved disulfide bonds. TFPs were initially characterized as snake alpha-neurotoxins, but later many studies showed their regulatory roles in different organisms. Despite a known expression of TFPs in vertebrates, they are poorly studied in other taxa.

Upregulation of cholinergic modulators Lypd6 and Lypd6b associated with autism drives anxiety and cognitive decline.

Intellectual disability and autistic features are associated with chromosome region 2q23.q23.2 duplication carrying LYPD6 and LYPD6B genes.

Molecular Basis for Mambalgin-2 Interaction with Heterotrimeric α-ENaC/ASIC1a/γ-ENaC Channels in Cancer Cells.

Cancer progression is characterized by microenvironmental acidification. Tumor cells adapt to low environmental pH by activating acid-sensing trimeric ion channels of the DEG/ENaC family. The α-ENaC/ASIC1a/γ-ENaC heterotrimeric channel is a tumor-specific acid-sensing channel, and its targeting can be considered a new strategy for cancer therapy.

Aβ1-42 Accumulation Accompanies Changed Expression of Ly6/uPAR Proteins, Dysregulation of the Cholinergic System, and Degeneration of Astrocytes in the Cerebellum of Mouse Model of Early Alzheimer Disease.

Alzheimer disease (AD) is a widespread neurodegenerative disease characterized by the accumulation of oligomeric toxic forms of β-amyloid (Aβ1-42) and dysfunction of the cholinergic system in the different brain regions. However, the exact mechanisms of AD pathogenesis and the role of the nicotinic acetylcholine receptors (nAChRs) in the disease progression remain unclear. Here, we revealed a decreased expression of a number of the Ly6/uPAR proteins targeting nAChRs in the cerebellum of 2xTg-AD mice (model of early AD) in comparison with non-transgenic mice both at mRNA and protein levels.

Crystal structure reveals canonical recognition of the phosphorylated cytoplasmic loop of human alpha7 nicotinic acetylcholine receptor by 14-3-3 protein.

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels composed of five homologous subunits. The homopentameric α7-nAChR, abundantly expressed in the brain, is involved in the regulation of the neuronal plasticity and memory and undergoes phosphorylation by protein kinase A (PKA). Here, we extracted native α7-nAChR from murine brain, validated its assembly by cryo-EM and showed that phosphorylation by PKA in vitro enables its interaction with the abundant human brain protein 14-3-3ζ.

Recombinant Production, NMR Solution Structure, and Membrane Interaction of the Phα1β Toxin, a TRPA1 Modulator from the Brazilian Armed Spider .

Phα1β (PnTx3-6) is a neurotoxin from the spider venom, originally identified as an antagonist of two ion channels involved in nociception: N-type voltage-gated calcium channel (Ca2.2) and TRPA1. In animal models, Phα1β administration reduces both acute and chronic pain.

Expression of Xanthorhodopsin in Escherichia coli.

Xanthorhodopsin (XR) from Salinibacter ruber is a light-driven proton pump containing retinal and a light-harvesting carotenoid antenna salinixanthin. Previous structure-functional studies of XR were conducted using a protein isolated from the native host only due to the absence of heterologous expression in Escherichia coli. In this paper, we describe cell-free synthesis and incorporation in lipid-protein nanodiscs of the recombinant XR that demonstrated its principal compatibility with E.

Orientational Preferences of GPI-Anchored Ly6/uPAR Proteins.

Ly6/uPAR proteins regulate many essential functions in the nervous and immune systems and epithelium. Most of these proteins contain single β-structural LU domains with three protruding loops and are glycosylphosphatidylinositol (GPI)-anchored to a membrane. The GPI-anchor role is currently poorly studied.

Membrane-mediated interaction of non-conventional snake three-finger toxins with nicotinic acetylcholine receptors.

Nicotinic acetylcholine receptor of α7 type (α7-nAChR) presented in the nervous and immune systems and epithelium is a promising therapeutic target for cognitive disfunctions and cancer treatment. Weak toxin from Naja kaouthia venom (WTX) is a non-conventional three-finger neurotoxin, targeting α7-nAChR with weak affinity. There are no data on interaction mode of non-conventional neurotoxins with nAChRs.

New Three-Finger Protein from Starfish Shares Structure and Pharmacology with Human Brain Neuromodulator Lynx2.

Three-finger proteins (TFPs) are small proteins with characteristic three-finger β-structural fold stabilized by the system of conserved disulfide bonds. These proteins have been found in organisms from different taxonomic groups and perform various important regulatory functions or act as components of snake venoms. Recently, four TFPs (Lystars 1-4) with unknown function were identified in the coelomic fluid proteome of starfish .

Mambalgin-2 Inhibits Lung Adenocarcinoma Growth and Migration by Selective Interaction With ASIC1/α-ENaC/γ-ENaC Heterotrimer.

Lung cancer is one of the most common cancer types in the world. Despite existing treatment strategies, overall patient survival remains low and new targeted therapies are required. Acidification of the tumor microenvironment drives the growth and metastasis of many cancers.

Extracellular Vesicles Derived from Acidified Metastatic Melanoma Cells Stimulate Growth, Migration, and Stemness of Normal Keratinocytes.

Metastatic melanoma is a highly malignant tumor. Melanoma cells release extracellular vesicles (EVs), which contribute to the growth, metastasis, and malignancy of neighboring cells by transfer of tumor-promoting miRNAs, mRNA, and proteins. Melanoma microenvironment acidification promotes tumor progression and determines EVs' properties.

Mambalgin-2 Inhibits Growth, Migration, and Invasion of Metastatic Melanoma Cells by Targeting the Channels Containing an ASIC1a Subunit Whose Up-Regulation Correlates with Poor Survival Prognosis.

Melanoma is an aggressive cancer characterized by the acidification of the extracellular environment. Here, we showed for the first time that extracellular media acidification increases proliferation, migration, and invasion of patient-derived metastatic melanoma cells and up-regulates cell-surface expression of acid-sensitive channels containing the ASIC1a, α-ENaC, and γ-ENaC subunits. No influence of media acidification on these processes was found in normal keratinocytes.

SLURP-1 Controls Growth and Migration of Lung Adenocarcinoma Cells, Forming a Complex With α7-nAChR and PDGFR/EGFR Heterodimer.

Secreted Ly6/uPAR-related protein 1 (SLURP-1) is a secreted Ly6/uPAR protein that negatively modulates the nicotinic acetylcholine receptor of α7 type (α7-nAChR), participating in control of cancer cell growth. Previously we showed, that a recombinant analogue of human SLURP-1 (rSLURP-1) diminishes the lung adenocarcinoma A549 cell proliferation and abolishes the nicotine-induced growth stimulation. Here, using multiplex immunoassay, we demonstrated a decrease in PTEN and mammalian target of rapamycin (mTOR) kinase phosphorylation in A549 cells upon the rSLURP-1 treatment pointing on down-regulation of the PI3K/AKT/mTOR signaling pathway.

Animal, Herb, and Microbial Toxins for Structural and Pharmacological Study of Acid-Sensing Ion Channels.

Acid-sensing ion channels (ASICs) are of the most sensitive molecular sensors of extracellular pH change in mammals. Six isoforms of these channels are widely represented in membranes of neuronal and non-neuronal cells, where these molecules are involved in different important regulatory functions, such as synaptic plasticity, learning, memory, and nociception, as well as in various pathological states. Structural and functional studies of both wild-type and mutant ASICs are essential for human care and medicine for the efficient treatment of socially significant diseases and ensure a comfortable standard of life.

Water-soluble variant of human Lynx1 positively modulates synaptic plasticity and ameliorates cognitive impairment associated with α7-nAChR dysfunction.

Lynx1 is a GPI-tethered protein colocalized with nicotinic acetylcholine receptors (nAChRs) in the brain areas important for learning and memory. Previously, we demonstrated that at low micromolar concentrations the water-soluble Lynx1 variant lacking GPI-anchor (ws-Lynx1) acts on α7-nAChRs as a positive allosteric modulator. We hypothesized that ws-Lynx1 could be used for improvement of cognitive processes dependent on nAChRs.

Human secreted protein SLURP-1 abolishes nicotine-induced proliferation, PTEN down-regulation and α7-nAChR expression up-regulation in lung cancer cells.

Human Ly-6/uPAR-related protein-1 (SLURP-1) is an allosteric negative modulator of the α7-type nicotinic acetylcholine receptor (α7-nAChR), one of the key receptors promoting nicotine-induced proliferation of lung cancer cells. Incubation of lung adenocarcinoma A549 cells with recombinant SLURP-1 (rSLURP-1) at concentrations >10 nM resulted in the significant decrease of the cell growth (~70%), while treatment of normal lung-derived WI-38 fibroblasts with rSLURP-1 did not influence the cell proliferation up to 1 μM of the protein. rSLURP-1 fully abolished the nicotine-induced increase of the cell proliferation, down-regulation of the expression of PTEN (the negative regulator of the AKT pathway, controlling the growth, survival, and proliferation of cancer cells), and up-regulation of the α7-nAChR expression in the A549 cells.