Production, composition, and mode of action of the painful defensive venom produced by a limacodid caterpillar, Doratifera vulnerans

Venoms have evolved independently several times in Lepidoptera. Limacodidae is a family with worldwide distribution, many of which are venomous in the larval stage, but the composition and mode of action of their venom is unknown. Here, we use imaging technologies, transcriptomics, proteomics, and functional assays to provide a holistic picture of the venom system of a limacodid caterpillar, Doratifera vulnerans. Contrary to dogma that defensive venoms are simple in composition, D. vulnerans produces a complex venom containing 151 proteinaceous toxins spanning 59 families, most of which are peptides <10 kDa. Three of the most abundant families of venom peptides (vulnericins) are 1) analogs of the adipokinetic hormone/corazonin-related neuropeptide, some of which are picomolar agonists of the endogenous insect receptor; 2) linear cationic peptides derived from cecropin, an insect innate immune peptide that kills bacteria and parasites by disrupting cell membranes; and 3) disulfide-rich knottins similar to those that dominate spider venoms. Using venom fractionation and a suite of synthetic venom peptides, we demonstrate that the cecropin-like peptides are responsible for the dominant pain effect observed in mammalian in vitro and in vivo nociception assays and therefore are likely to cause pain after natural envenomations by D. vulnerans. Our data reveal convergent molecular evolution between limacodids, hymenopterans, and arachnids and demonstrate that lepidopteran venoms are an untapped source of novel bioactive peptides.

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A Novel Human Ada2 Homologue Functions with Gcn5 or Brg1 To Coactivate Transcription

Molecular and Cellular Biology ◽

10.1128/mcb.23.19.6944-6957.2003 ◽

2003 ◽

Vol 23 (19) ◽

pp. 6944-6957 ◽

Cited By ~ 46

Author(s):

Nickolai A. Barlev ◽

Alexander V. Emelyanov ◽

Paola Castagnino ◽

Philip Zegerman ◽

Andrew J. Bannister ◽

...

Keyword(s):

Histone Acetylation ◽

Chromatin Remodeling ◽

Adaptor Protein ◽

Saga Complex ◽

Yeast Two Hybrid ◽

Functional Assays ◽

Two Hybrid ◽

Histone Acetyltransferase Activity

ABSTRACT In yeast, the transcriptional adaptor yeast Ada2 (yAda2) is a part of the multicomponent SAGA complex, which possesses histone acetyltransferase activity through action of the yGcn5 catalytic enzyme. yAda2, among several SAGA proteins, serves to recruit SAGA to genes via interactions with promoter-bound transcription factors. Here we report identification of a new human Ada2 homologue, hAda2β. Ada2β differs both biochemically and functionally from the previously characterized hAda2α, which is a stable component of the human PCAF (human Gcn5 homologue) acetylase complex. Ada2β, relative to Ada2α, interacted selectively, although not stably, with the Gcn5-containing histone acetylation complex TFTC/STAGA. In addition, Ada2β interacted with Baf57 (a component of the human Swi/Snf complex) in a yeast two-hybrid screen and associated with human Swi/Snf in vitro. In functional assays, hAda2β (but not Ada2α), working in concert with Gcn5 (but not PCAF) or Brg1 (the catalytic component of hSwi/Snf complex), increased transcription via the B-cell-specific transcription factor Pax5/BSAP. These findings support the view that Gcn5 and PCAF have distinct roles in vivo and suggest a new mechanism of coactivator function, in which a single adaptor protein (Ada2β) can coordinate targeting of both histone acetylation and chromatin remodeling activities.

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The Transcriptional Regulator CpsY Is Important for Innate Immune Evasion in Streptococcus pyogenes

Infection and Immunity ◽

10.1128/iai.00925-16 ◽

2016 ◽

Vol 85 (3) ◽

Cited By ~ 2

Author(s):

Luis A. Vega ◽

Kayla M. Valdes ◽

Ganesh S. Sundar ◽

Ashton T. Belew ◽

Emrul Islam ◽

...

Keyword(s):

Streptococcus Pyogenes ◽

Immune Evasion ◽

Immune Cell ◽

Group A Streptococcus ◽

Transcriptional Regulator ◽

Innate Immune ◽

Content Type ◽

Human Host

ABSTRACTAs an exclusively human pathogen,Streptococcus pyogenes(the group A streptococcus [GAS]) has specifically adapted to evade host innate immunity and survive in multiple tissue niches, including blood. GAS can overcome the metabolic constraints of the blood environment and expresses various immunomodulatory factors necessary for survival and immune cell resistance. Here we present our investigation of one such factor, the predicted LysR family transcriptional regulator CpsY. The encoding gene,cpsY, was initially identified as being required for GAS survival in a transposon-site hybridization (TraSH) screen in whole human blood. CpsY is homologous with transcriptional regulators ofStreptococcus mutans(MetR),Streptococcus iniae(CpsY), andStreptococcus agalactiae(MtaR) that regulate methionine transport, amino acid metabolism, resistance to neutrophil-mediated killing, and survivalin vivo. Our investigation indicated that CpsY is involved in GAS resistance to innate immune cells of its human host. However, GAS CpsY does not manifest thein vitrophenotypes of its homologs in other streptococcal species. GAS CpsY appears to regulate a small set of genes that is markedly different from the regulons of its homologs. The differential expression of these genes depends on the growth medium, and CpsY modestly influences their expression. The GAS CpsY regulon includes known virulence factors (mntE,speB,spd,nga[spn],prtS[SpyCEP], andsse) and cell surface-associated factors of GAS (emm1,mur1.2,sibA[cdhA], andM5005_Spy0500). Intriguingly, the loss of CpsY in GAS does not result in virulence defects in murine models of infection, suggesting that CpsY function in immune evasion is specific to the human host.

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Vasopressin as a neuroendocrine regulator of anterior pituitary hormone secretion

Acta Endocrinologica ◽

10.1530/acta.0.1290489 ◽

1993 ◽

Vol 129 (6) ◽

pp. 489-496 ◽

Cited By ~ 33

Author(s):

Andreas Kjær

Keyword(s):

Arginine Vasopressin ◽

Mode Of Action ◽

Anterior Pituitary ◽

Hormone Secretion ◽

Pituitary Hormones ◽

Pituitary Hormone ◽

Anterior Pituitary Hormones ◽

Anterior Pituitary Hormone

Secretion of the anterior pituitary hormones adrenocorticotropin (ACTH), β-endorphin and prolactin (PRL) is complex and involves a variety of factors. This review focuses on the involvement of arginine-vasopressin (AVP) in neuroendocrine regulation of these anterior pituitary hormones with special reference to receptor involvement, mode of action and origin of AVP. Arginine-vasopressin may act via at least two types of receptors: V1− and V2−receptors, where the pituitary V1−receptor is designated V1b. The mode of action of AVP may be mediating, i.e. anterior pituitary hormone secretion is transmitted via release of AVP, or the mode of action may be permissive, i.e. the presence of AVP at a low and constant level is required for anterior pituitary hormones to be stimulated. Under in vivo conditions, the AVP-induced release of ACTH and β-endorphin is mainly mediated via activation of hypothalamic V1− receptors, which subsequently leads to the release of corticotropin-releasing hormone. Under in vitro conditions, the AVP-stimulated release of ACTH and β-endorphin is mediated via pituitary V1b− receptors. The mode of action of AVP in the ACTH and β-endorphin response to stress and to histamine, which is involved in stress-induced secretion of anterior pituitary hormones, is mediating (utilizing V1− receptors) as well as permissive (utilizing mainly V1− but also V2−receptors). The AVP-induced release of PRL under in vivo conditions is conveyed mainly via activation of V1−receptors but V2−receptors and probably additional receptor(s) may also play a role. In stress- and histamine induced PRL secretion the role of AVP is both mediating (utilizing V1 −receptors) and permissive (utilizing both V1− and V2− receptors). Arginine-vasopressin may be a candidate for the PRL-releasing factor recently identified in the posterior pituitary gland. Arginine-vasopressin of both magno- and parvocellular origin may be involved in the regulation of anterior pituitary hormone secretion and may reach the corticotrophs and the lactotrophs via three main routes: the peripheral circulation, the long pituitary portal vessels or the short pituitary portal vessels.

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IMMU-53. STING-ING GLIOBLASTOMA WITH SPHERICAL NUCLEIC ACIDS

Neuro-Oncology ◽

10.1093/neuonc/noab196.412 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi104-vi105

Author(s):

Akanksha Mahajan ◽

Lisa Hurley ◽

Serena Tommasini-Ghelfi ◽

Corey Dussold ◽

Alexander Stegh ◽

...

Keyword(s):

Nucleic Acid ◽

High Surface ◽

Biological Properties ◽

Innate Immune ◽

Limiting Factors ◽

Nucleic Acid Delivery ◽

Sting Pathway ◽

Spherical Nucleic Acids

Abstract The Stimulator of Interferon Genes (STING) pathway represents a major innate immune sensing mechanism for tumor-derived DNA. Modified cyclic dinucleotides (CDNs) that mimic the endogenous STING ligand cGAMP are currently being explored in patients with solid tumors that are amenable to intratumoral delivery. Inadequate bioavailability and insufficient lipophilicity are limiting factors for clinical CDN development, in particular when consideration is given to systemic administration approaches. We have shown that the formulation of oligonucleotides into Spherical Nucleic Acid (SNA) nanostructures, i.e.,the presentation of oligonucleotides at high density on the surface of nanoparticle cores, lead to biochemical and biological properties that are radically different from those of linear oligonucleotides. First-generation brain-penetrant siRNA-based SNAs (NCT03020017, recurrent GBM) have recently completed early clinical trials. Here, we report the development of a STING-agonistic immunotherapy by targeting cGAS, the sensor of cytosolic dsDNA upstream of STING, with SNAs presenting dsDNA at high surface density. The strategy of using SNAs exploits the ability of cGAS to raise STING responses by delivering dsDNA and inducing the catalytic production of endogenous CDNs. SNA nanostructures carrying a 45bp IFN-simulating dsDNA oligonucleotide, the most commonly used and widely characterized cGAS activator, potently activated the cGAS-STING pathway in vitro and in vivo. In a poorly immunogenic and highly aggressive syngeneic mouse glioma model, in which tumours were well-established, only one dose of intranasal treatment with STING-SNAs decelerated tumour growth, improved survival and importantly, was well-tolerated. Our use of SNAs addresses the challenges of nucleic acid delivery to intracranial tumor sites via intranasal route, exploits the binding of dsDNA molecules on the SNA surface to enhance the formation of a dimeric cGAS:DNA complex and establishes cGAS-agonistic SNAs as a novel class of immune-stimulatory modalities for triggering innate immune responses against tumor.

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ADAR1 function affects HPV replication and is associated to recurrent human papillomavirus-induced dysplasia in HIV coinfected individuals

Scientific Reports ◽

10.1038/s41598-019-56422-x ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Maria Pujantell ◽

Roger Badia ◽

Iván Galván-Femenía ◽

Edurne Garcia-Vidal ◽

Rafael de Cid ◽

...

Keyword(s):

Human Papillomavirus ◽

Immune Activation ◽

Hpv Infection ◽

Innate Immune ◽

Type I ◽

Innate Immune Activation ◽

Enhanced Expression

AbstractInfection by human papillomavirus (HPV) alters the microenvironment of keratinocytes as a mechanism to evade the immune system. A-to-I editing by ADAR1 has been reported to regulate innate immunity in response to viral infections. Here, we evaluated the role of ADAR1 in HPV infection in vitro and in vivo. Innate immune activation was characterized in human keratinocyte cell lines constitutively infected or not with HPV. ADAR1 knockdown induced an innate immune response through enhanced expression of RIG-I-like receptors (RLR) signaling cascade, over-production of type-I IFNs and pro-inflammatory cytokines. ADAR1 knockdown enhanced expression of HPV proteins, a process dependent on innate immune function as no A-to-I editing could be identified in HPV transcripts. A genetic association study was performed in a cohort of HPV/HIV infected individuals followed for a median of 6 years (range 0.1–24). We identified the low frequency haplotype AACCAT significantly associated with recurrent HPV dysplasia, suggesting a role of ADAR1 in the outcome of HPV infection in HIV+ individuals. In summary, our results suggest that ADAR1-mediated innate immune activation may influence HPV disease outcome, therefore indicating that modification of innate immune effectors regulated by ADAR1 could be a therapeutic strategy against HPV infection.

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Virulent Shigella flexneri subverts the host innate immune response through manipulation of antimicrobial peptide gene expression

Journal of Experimental Medicine ◽

10.1084/jem.20071698 ◽

2008 ◽

Vol 205 (5) ◽

pp. 1121-1132 ◽

Cited By ~ 105

Author(s):

Brice Sperandio ◽

Béatrice Regnault ◽

Jianhua Guo ◽

Zhi Zhang ◽

Samuel L. Stanley ◽

...

Keyword(s):

Innate Immunity ◽

Shigella Flexneri ◽

Host Cells ◽

Virulence Plasmid ◽

Cationic Peptides ◽

Immunity Genes ◽

Genes Encoding ◽

Peptide Gene

Antimicrobial factors are efficient defense components of the innate immunity, playing a crucial role in the intestinal homeostasis and protection against pathogens. In this study, we report that upon infection of polarized human intestinal cells in vitro, virulent Shigella flexneri suppress transcription of several genes encoding antimicrobial cationic peptides, particularly the human β-defensin hBD-3, which we show to be especially active against S. flexneri. This is an example of targeted survival strategy. We also identify the MxiE bacterial regulator, which controls a regulon encompassing a set of virulence plasmid-encoded effectors injected into host cells and regulating innate signaling, as being responsible for this dedicated regulatory process. In vivo, in a model of human intestinal xenotransplant, we confirm at the transcriptional and translational level, the presence of a dedicated MxiE-dependent system allowing S. flexneri to suppress expression of antimicrobial cationic peptides and promoting its deeper progression toward intestinal crypts. We demonstrate that this system is also able to down-regulate additional innate immunity genes, such as the chemokine CCL20 gene, leading to compromised recruitment of dendritic cells to the lamina propria of infected tissues. Thus, S. flexneri has developed a dedicated strategy to weaken the innate immunity to manage its survival and colonization ability in the intestine.

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Characteristics of Food Protein-Derived Antidiabetic Bioactive Peptides: A Literature Update

International Journal of Molecular Sciences ◽

10.3390/ijms22179508 ◽

2021 ◽

Vol 22 (17) ◽

pp. 9508

Author(s):

Nhung Thi Phuong Nong ◽

Jue-Liang Hsu

Keyword(s):

Bioactive Peptides ◽

Protein Hydrolysate ◽

Tyrosine Phosphatase ◽

Food Protein ◽

Dpp Iv ◽

Glucosidase Inhibitors ◽

Commercial Applications ◽

Ptp 1B

Diabetes, a glucose metabolic disorder, is considered one of the biggest challenges associated with a complex complication of health crises in the modern lifestyle. Inhibition or reduction of the dipeptidyl peptidase IV (DPP-IV), alpha-glucosidase, and protein-tyrosine phosphatase 1B (PTP-1B) enzyme activities or expressions are notably considered as the promising therapeutic strategies for the management of type 2 diabetes (T2D). Various food protein-derived antidiabetic bioactive peptides have been isolated and verified. This review provides an overview of the DPP-IV, PTP-1B, and α-glucosidase inhibitors, and updates on the methods for the discovery of DPP-IV inhibitory peptides released from food-protein hydrolysate. The finding of novel bioactive peptides involves studies about the strategy of separation fractionation, the identification of peptide sequences, and the evaluation of peptide characteristics in vitro, in silico, in situ, and in vivo. The potential of bioactive peptides suggests useful applications in the prevention and management of diabetes. Furthermore, evidence of clinical studies is necessary for the validation of these peptides’ efficiencies before commercial applications.

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Synergy and remarkable specificity of antimicrobial peptides in vivo using a systematic knockout approach

eLife ◽

10.7554/elife.44341 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 29

Author(s):

Mark Austin Hanson ◽

Anna Dostálová ◽

Camilla Ceroni ◽

Mickael Poidevin ◽

Shu Kondo ◽

...

Keyword(s):

Antimicrobial Peptides ◽

Fungal Pathogens ◽

Gene Editing ◽

Cationic Peptides ◽

Gram Negative Bacteria ◽

Biological Processes ◽

Gram Negative ◽

Bacteria And Fungi

Antimicrobial peptides (AMPs) are host-encoded antibiotics that combat invading microorganisms. These short, cationic peptides have been implicated in many biological processes, primarily involving innate immunity. In vitro studies have shown AMPs kill bacteria and fungi at physiological concentrations, but little validation has been done in vivo. We utilized CRISPR gene editing to delete most known immune-inducible AMPs of Drosophila, namely: 4 Attacins, 2 Diptericins, Drosocin, Drosomycin, Metchnikowin and Defensin. Using individual and multiple knockouts, including flies lacking these ten AMP genes, we characterize the in vivo function of individual and groups of AMPs against diverse bacterial and fungal pathogens. We found that Drosophila AMPs act primarily against Gram-negative bacteria and fungi, contributing either additively or synergistically. We also describe remarkable specificity wherein certain AMPs contribute the bulk of microbicidal activity against specific pathogens, providing functional demonstrations of highly specific AMP-pathogen interactions in an in vivo setting.

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Zinc oxide microrods and nanorods: different antibacterial activity and their mode of action against Gram-positive bacteria

RSC Advances ◽

10.1039/c4ra08462d ◽

2014 ◽

Vol 4 (99) ◽

pp. 56031-56040 ◽

Cited By ~ 42

Author(s):

Ilaria Rago ◽

Chandrakanth Reddy Chandraiahgari ◽

Maria P. Bracciale ◽

Giovanni De Bellis ◽

Elena Zanni ◽

...

Keyword(s):

Zinc Oxide ◽

Antibacterial Activity ◽

Mode Of Action ◽

Gram Positive ◽

Gram Positive Bacteria

ZnO micro and nanorods, produced through simple and inexpensive techniques, resulted to be strong antimicrobials against Gram-positive bacteria, in vitro as well as in vivo, by altering cell outer structures like membrane and exopolysaccharides.

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Combined Stimulation of Toll-Like Receptor 5 and NOD1 Strongly Potentiates Activity of NF-κB, Resulting in Enhanced Innate Immune Reactions and Resistance to Salmonella enterica Serovar Typhimurium Infection

Infection and Immunity ◽

10.1128/iai.00525-13 ◽

2013 ◽

Vol 81 (10) ◽

pp. 3855-3864 ◽

Cited By ~ 23

Author(s):

Amir I. Tukhvatulin ◽

Ilya I. Gitlin ◽

Dmitry V. Shcheblyakov ◽

Natalia M. Artemicheva ◽

Lyudmila G. Burdelya ◽

...

Keyword(s):

Critical Role ◽

Immune Defense ◽

Innate Immune ◽

Microbial Infection ◽

Immune Reactions ◽

Content Type ◽

Essential Components ◽

Stimulation Of

ABSTRACTPathogen recognition receptors (PRRs) are essential components of host innate immune systems that detect specific conserved pathogen-associated molecular patterns (PAMPs) presented by microorganisms. Members of two families of PRRs, transmembrane Toll-like receptors (TLRs 1, 2, 4, 5, and 6) and cytosolic NOD receptors (NOD1 and NOD2), are stimulated upon recognition of various bacterial PAMPs. Such stimulation leads to induction of a number of immune defense reactions, mainly triggered via activation of the transcription factor NF-κB. While coordination of responses initiated via different PRRs sensing multiple PAMPS present during an infection makes clear biological sense for the host, such interactions have not been fully characterized. Here, we demonstrate that combined stimulation of NOD1 and TLR5 (as well as other NOD and TLR family members) strongly potentiates activity of NF-κB and induces enhanced levels of innate immune reactions (e.g., cytokine production) bothin vitroandin vivo. Moreover, we show that an increased level of NF-κB activity plays a critical role in formation of downstream responses. In live mice, synergy between these receptors resulting in potentiation of NF-κB activity was organ specific, being most prominent in the gastrointestinal tract. Coordinated activity of NOD1 and TLR5 significantly increased protection of mice against enteroinvasiveSalmonellainfection. Obtained results suggest that cooperation of NOD and TLR receptors is important for effective responses to microbial infectionin vivo.

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