174 Accepted for oral presentation: A POLYCLONAL ANTIBODY TO THE PRE‐PORE LOOP OF TRPV1 BLOCKS CHANNEL ACTIVATION

Klionsky, Lana; Tamir, Rami; Holzinger, Bob; Bi, Vivian; Kim, H.; Martin, Francis H.; Louis, Jean Claude; Treanor, James; Gavva, Narender R.; Talvenheimo, Jane

doi:10.1016/s1090-3801(06)60177-8

Cited by 3 publications

(4 citation statements)

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“…Rabbit anti-rat TRPV1 polyclonal antibodies (Ab-156H) specific to the TRPV1 loop (considered as pH sensor) have something similar in inhibition result to APHC1. These antibodies were not able to block completely capsaicin-and anandamide-induced response in saturating concentrations and had maximum inhibition of ϳ55% (46). Most likely, APHC1 shares the mechanism of action suggested to Ab-156H that probably partially locks the channel conformation in the closed state.…”

Section: Discussionmentioning

confidence: 95%

Analgesic Compound from Sea Anemone Heteractis crispa Is the First Polypeptide Inhibitor of Vanilloid Receptor 1 (TRPV1)

Andreev

Козлов

Koshelev

et al. 2008

Journal of Biological Chemistry

144

139

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Venomous animals from distinct phyla such as spiders, scorpions, snakes, cone snails, or sea anemones produce small toxic proteins interacting with a variety of cell targets. Their bites often cause pain. One of the ways of pain generation is the activation of TRPV1 channels. Screening of 30 different venoms from spiders and sea anemones for modulation of TRPV1 activity revealed inhibitors in tropical sea anemone Heteractis crispa venom. Several separation steps resulted in isolation of an inhibiting compound. This is a 56-residue-long polypeptide named APHC1 that has a Bos taurus trypsin inhibitor (BPTI)/Kunitztype fold, mostly represented by serine protease inhibitors and ion channel blockers. APHC1 acted as a partial antagonist of capsaicin-induced currents (32 ؎ 9% inhibition) with half-maximal effective concentration (EC 50 ) 54 ؎ 4 nM. In vivo, a 0.1 mg/kg dose of APHC1 significantly prolonged tail-flick latency and reduced capsaicin-induced acute pain. Therefore, our results can make an important contribution to the research into molecular mechanisms of TRPV1 modulation and help to solve the problem of overactivity of this receptor during a number of pathological processes in the organism.During the evolutionary process, different poisonous animals combined a set of bioactive compounds in their venoms used mainly to paralyze prey and/or as a defense against predators (1, 2). Bites of these creatures may induce inflammation, pain, tissue necrosis, allergic reactions, and neurotoxic effects such as convulsions, paralysis, respiratory failure, and cardiovascular stroke (3). Numerous toxic peptides are found within these venoms, and some of them can discriminate between closely related cellular targets that make them attractive for drug development and scientific use (4). Molecules accounting for lethal and inflammation effects of venoms have been extensively characterized, but less is known about the properties of other compounds. We concentrated on searching the compounds able to reduce TRPV1 2 conductivity. These receptors are expressed in mammalians in small and medium size dorsal root ganglion neurons and are localized in peripheral and central neuronal system (5-7). At present, it is accepted that TRPV1 receptors are molecular integrators of pain stimulus and initiate neuronal response during inflammation. Experiments with knock-out mice lacking the gene of vanilloid receptor clearly demonstrate its role in pain perception (8, 9). Since vanilloid receptor had been disclosed and cloned in 1997, it became an object of numerous investigations as a potential target for novel drugs against pain of different origin (10). As recently reported, vanillotoxins from a tarantula Psalmopoeus cambridgei directly activate TRPV1 in micromolar concentrations, causing pain effect in the same way as capsaicin does (11). Venoms of several jellyfish also seem to interact with TRPV1, knocking down its desensitization (12). A number of small molecules were synthesized that selectively inhibit TRPV1 in nanomolar concentration ...

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Section: Discussionmentioning

confidence: 95%

Analgesic Compound from Sea Anemone Heteractis crispa Is the First Polypeptide Inhibitor of Vanilloid Receptor 1 (TRPV1)

Andreev

Козлов

Koshelev

et al. 2008

Journal of Biological Chemistry

144

139

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“…Polyclonal antibody directed against E3 of rat TRPV1 was effective at blocking channel activation by protons and heat, as well as chemical activation by the TRPV1 agonist anandamide and capsaicin [29]. Antibody inhibition was not reliant on the capsaicin binding pocket, as inhibition of channel activity was also achieved in a capsaicin insensitive mutant, suggesting that E3-targeted antibodies do not interact with agonist binding sites, particularly as the agonists tested act via independent mechanisms, and instead may obstruct the pore directly or stabilise a closed channel state.…”

Section: E3 Targeted Antibodies: Principles and Examplesmentioning

confidence: 99%

“…Monoclonal antibodies can overcome such problems but identifying a functional monoclonal antibody against an ion channel may be a significant challenge. Unfortunately, monoclonal antibodies to E3 of TRPV1 lacked functional effect, even though polyclonal antibodies were effective [29]. The authors suggested that a mixed population of polyclonal antibodies might be necessary to achieve channel block.…”

Section: Monoclonal Antibodiesmentioning

confidence: 99%

Extracellular Ion Channel Inhibitor Antibodies

Naylor¹,

Beech

2009

TODDISJ

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For many ion channels there are no specific pharmacological agents and this impedes searches for the physiological and pathological functions of the ion channels in native systems and restricts opportunity for therapeutic drug development. Antibodies can display high specificity for their target proteins and are routinely engineered to recognise proteins in many experimental procedures and increasingly as therapeutic agents. The unlimited diversity and potential for high specificity make antibodies attractive as biological tools and drugs, although they are not without problems. Along with other investigators we have explored targeting of the E3 extracellular loop (or turret) as an approach for the generation of antibodies with the potential to block certain types of ion channel with isoform specificity. The approach has led to success with nine ion channels and effective use in vitro and in vivo. Here we review current knowledge and experience of channel-blocking antibodies, focusing particularly but not exclusively on E3-targeting.

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“…Xu et al 138 applied E3 targeting to the transient receptor potential (TRP) Ca 2+ channel member TRPC5 and the voltage-gated sodium channel Na V 1.5 to generate target-specific polyclonal inhibitors, while Yang et al 139 used a 14-amino acid E3 peptide from the external end of the human Kv1.3 pore region to generate a polyclonal antibody by immunization. A variety of functional polyclonal antibodies have been described, 137 although one study found that polyclonals raised against E3 (Glu 600 to Pro 623 ) of TRPV1 allosterically blocked function, 140 but monoclonal antibodies were ineffective. The latter were raised in a separate immunization using Thr 598 to Cys 636 , and lack of effect could be explained by targeting single versus multiple epitopes but possibly also by clone prioritization based on cell binding rather than function.…”

Section: Ion Channel Targetsmentioning

confidence: 99%

New Horizons in Therapeutic Antibody Discovery: Opportunities and Challenges versus Small-Molecule Therapeutics

Smith¹

2015

SLAS Discovery

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Antibody drugs have become an increasingly significant component of the therapeutic landscape. Their success has been driven by some of their unique properties, in particular their very high specificity and selectivity, in contrast to the offtarget liabilities of small molecules (SMs). Antibodies can bring additional functionality to the table with their ability to interact with the immune system, and this can be further manipulated with advances in antibody engineering. This review summarizes what antibody therapeutics have achieved to date and what opportunities and challenges lie ahead. The target landscape for large molecules (LMs) versus SMs and some of the challenges for antibody drug development are discussed. Effective penetration of membrane barriers and intracellular targeting is one challenge, particularly across the highly resistant blood-brain barrier. The expanding pipeline of antibody-drug conjugates offers the potential to combine SM and LM modalities in a variety of creative ways, and antibodies also offer exciting potential to build bi-and multispecific molecules. The ability to pursue more challenging targets can also be further exploited but highlights the need for earlier screening in functional cell-based assays. I discuss how this might be addressed given the practical constraints imposed by high-throughput screening sample type and process differences in antibody primary screening.

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174 Accepted for oral presentation: A POLYCLONAL ANTIBODY TO THE PRE‐PORE LOOP OF TRPV1 BLOCKS CHANNEL ACTIVATION

Cited by 3 publications

References 0 publications

Analgesic Compound from Sea Anemone Heteractis crispa Is the First Polypeptide Inhibitor of Vanilloid Receptor 1 (TRPV1)

Analgesic Compound from Sea Anemone Heteractis crispa Is the First Polypeptide Inhibitor of Vanilloid Receptor 1 (TRPV1)

Extracellular Ion Channel Inhibitor Antibodies

New Horizons in Therapeutic Antibody Discovery: Opportunities and Challenges versus Small-Molecule Therapeutics

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