New ratiometric fluorescent calcium indicators with moderately attenuated binding affinities

Gee, Kyle R.; Archer, Eric A.; Lapham, Laura A.; Leonard, Mary E.; Zhou, Zhang‐Lin; Bingham, John P.; Diwu, Zhenjun

doi:10.1016/s0960-894x(00)00280-8

Cited by 28 publications

(23 citation statements)

References 11 publications

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“…A change in the fluorescence of the Ca-indicator solution was not observed until TS was added to nearly 1000 times greater concentration, establishing that TS is unable to compete for calcium in the presence of Fura-4F. Because the binding affinity of Fura-4F for Ca(II) is 0.77 μM,[42, 43] the relative affinity of TS for calcium must be significantly weaker.…”

Section: Resultsmentioning

confidence: 99%

Prochelators triggered by hydrogen peroxide provide hexadentate iron coordination to impede oxidative stress

Leed

Wolkow

Pham

et al. 2011

Journal of Inorganic Biochemistry

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Prochelators are agents that have little affinity for metal ions until they undergo a chemical conversion. Three new aryl boronate prochelators are presented that are responsive to hydrogen peroxide to provide hexadentate ligands for chelating metal ions. TRENBSIM (tris[(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzylidene)-2-aminoethyl]amine), TRENBSAM (tris[(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoyl)-2-aminoethyl]amine), and TB (tris[(2-boronic acid-benzyl)2-aminoethyl]amine) convert to TRENSIM (tris[(salicylideneamino)ethyl]amine), TRENSAM (tris[(2-hydroxybenzoyl)-2-aminoethyl]amine), and TS (tris[2-hydroxybenzyl)2-aminoethyl]amine), respectively. The prochelators were characterized by 11B NMR, and the structures of TRENBSAM, TRENBSIM, and the Fe(III) complex of TS were determined by X-ray crystallography. Of the three prochelator/chelator pairs, TB/TS was identified as the most promising for biological applications, as they prevent iron and copper-induced hydroxyl radical generation in an in vitro assay. TB has negligible interactions with metal ions, whereas TS has apparent binding constants (log K′) at pH 7.4 of 15.87 for Cu(II), 9.67 Zn(II) and 14.42 for Fe(III). Up to 1 mM TB was nontoxic to retinal pigment epithelial cells, whereas 10 μM TS induced cell death. TS protected cells against H2O2-induced death, but only within a 1–10 μM range. TB, on the other hand, had a much broader window of protection, suggesting that it may be a useful agent for preventing metal-promoted oxidative damage.

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Section: Resultsmentioning

confidence: 99%

Prochelators triggered by hydrogen peroxide provide hexadentate iron coordination to impede oxidative stress

Leed

Wolkow

Pham

et al. 2011

Journal of Inorganic Biochemistry

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“…Fura-2, as well as some of its lower affinity derivatives (fura-2, namely fura-4F, fura-5F, fura-6F and fura-FF) has wide sensitivity ranging from ~100 nM to ~100 μM. (59-62)…”

Section: ) High Affinity Ca2+ Indicatorsmentioning

confidence: 99%

Chemical calcium indicators

Paredes

Etzler

Watts

et al. 2008

Methods

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Our understanding of the underlying mechanisms of Ca 2+ signaling as well as our appreciation for its ubiquitous role in cellular processes and has been rapidly advanced, in large part, due to the development of fluorescent Ca 2+ indicators. In this chapter, we discuss some of the most common chemical Ca 2+ indicators that are widely used for the investigation of intracellular Ca 2+ signaling. Advantages, limitations and relevant procedures will be presented for each dye including their spectral qualities, dissociation constants, chemical forms, loading methods and equipment for optimal imaging. Chemical indicators that are now available allow for intracellular Ca 2+ detection over a very large range (<50 nM to >50 μM). Higher affinity indicators can be used to quantify Ca 2+ levels in the cytosol while lower affinity indicators can be optimized for measuring Ca 2+ in subcellular compartments with higher concentrations. Indicators can be classified into either single wavelength or ratiometric dyes. Both classes require specific lasers, filters, and/or detection methods that are dependent upon their spectral properties and both classes have advantages and limitations. Single wavelength indicators are generally very bright and optimal for Ca 2+ detection when more than one fluorophore is being imaging. Ratiometric indicators can be calibrated very precisely and they minimize the most common problems associated with chemical Ca 2+ indicators including uneven dye loading, leakage, photobleaching and changes in cell volume. Recent technical advances that permit in vivo Ca 2+ measurements will also be discussed.

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“…3E). Because the Ca 2ϩ -indicator Fluo-4 AM is a single wavelength dye (Gee et al, 2000, Sato et al, 2007, we also performed these experiments using the ratiometric probe Fura mice perfused with ice-cold saline followed by cresyl violet solution (A). Arrows: BA, PcomA.…”

Section: Bax Deficiency Protects Against Neuronal Cell Death In Vitromentioning

confidence: 99%

Bax Regulates Neuronal Ca²⁺Homeostasis

et al. 2015

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Excessive Ca 2ϩ entry during glutamate receptor overactivation ("excitotoxicity") induces acute or delayed neuronal death. We report here that deficiency in bax exerted broad neuroprotection against excitotoxic injury and oxygen/glucose deprivation in mouse neocortical neuron cultures and reduced infarct size, necrotic injury, and cerebral edema formation after middle cerebral artery occlusion in mice. Neuronal Ca 2ϩ and mitochondrial membrane potential (⌬ m ) analysis during excitotoxic injury revealed that bax-deficient neurons showed significantly reduced Ca 2ϩ transients during the NMDA excitation period and did not exhibit the deregulation of ⌬ m that was observed in their wild-type (WT) counterparts. Reintroduction of bax or a bax mutant incapable of proapoptotic oligomerization equally restored neuronal Ca 2ϩ dynamics during NMDA excitation, suggesting that Bax controlled Ca 2ϩ signaling independently of its role in apoptosis execution. Quantitative confocal imaging of intracellular ATP or mitochondrial Ca 2ϩ levels using FRET-based sensors indicated that the effects of bax deficiency on Ca 2ϩ handling were not due to enhanced cellular bioenergetics or increased Ca 2ϩ uptake into mitochondria. We also observed that mitochondria isolated from WT or bax-deficient cells similarly underwent Ca 2ϩ -induced permeability transition. However, when Ca 2ϩ uptake into the sarco/endoplasmic reticulum was blocked with the Ca 2ϩ -ATPase inhibitor thapsigargin, bax-deficient neurons showed strongly elevated cytosolic Ca 2ϩ levels during NMDA excitation, suggesting that the ability of Bax to support dynamic ER Ca 2ϩ handling is critical for cell death signaling during periods of neuronal overexcitation.

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New ratiometric fluorescent calcium indicators with moderately attenuated binding affinities

Cited by 28 publications

References 11 publications

Prochelators triggered by hydrogen peroxide provide hexadentate iron coordination to impede oxidative stress

Prochelators triggered by hydrogen peroxide provide hexadentate iron coordination to impede oxidative stress

Chemical calcium indicators

Bax Regulates Neuronal Ca²⁺Homeostasis

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New ratiometric fluorescent calcium indicators with moderately attenuated binding affinities

Cited by 28 publications

References 11 publications

Prochelators triggered by hydrogen peroxide provide hexadentate iron coordination to impede oxidative stress

Prochelators triggered by hydrogen peroxide provide hexadentate iron coordination to impede oxidative stress

Chemical calcium indicators

Bax Regulates Neuronal Ca2+Homeostasis

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Product

Resources

About

Bax Regulates Neuronal Ca²⁺Homeostasis