scholarly journals Zinc-independent activation of Toll-like receptor 4 by S100A9

2019 ◽  
Author(s):  
Andrea N. Loes ◽  
Ran Shi ◽  
Michael J. Harms
Keyword(s):  
Inductively Coupled Plasma ◽  
Site Directed Mutagenesis ◽  
Titration Calorimetry ◽  
Functional Assay ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
A Cell

ABSTRACTThe homodimer formed by the protein S100A9 induces inflammation through Toll-like receptor 4 (TLR4), playing critical roles in both healthy and pathological innate immune responses. The molecular mechanism by which S100A9 activates TLR4 remains unknown. Previously, the interaction between purified S100A9 and TLR4 was shown to depend on Zn2+; however, the Zn2+ binding site(s) on S100A9 were not identified. Here, we investigated the role of Zn2+ binding in the pro-inflammatory activity of S100A9. We found that the S100A9 homodimer was prone to reversible, Zn2+-dependent aggregation in vitro. Using a combination of site-directed mutagenesis and Isothermal Titration Calorimetry (ITC), we identified multiple residues that contribute to Zn2+ binding in S100A9. We then used mutagenesis to construct a version of S100A9 with no detectable Zn2+ binding by either ITC or Inductively Coupled Plasma-Mass Spectrometry. This protein did not exhibit aggregation upon addition of saturating Zn2+. Further, despite the lack of Zn2+-binding, this protein was capable of activating TLR4 in a cell-based functional assay. We then modified the functional assay so the Zn2+ concentration was exceedingly low relative to the concentration of S100A9 added. Again, S100A9 was able to activate TLR4. This reveals that, despite the ability of S100A9 to bind Zn2+, S100A9 does not require Zn2+ to activate TLR4. Our work represents an important step in clarifying the nature of the interaction between S100A9 and TLR4.

Evaluation of the nanodebris produced by in vitro degradation of titanium-based dental implants in the presence of bacteria using single particle and single cell inductively coupled plasma mass spectrometry.

2021 ◽  
Author(s):  
Marzia Cosmi ◽  
Nathaly Gonzalez-Quiñonez ◽  
Pablo Tejerina Díaz ◽  
Ángel Manteca ◽  
Elisa Blanco González ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Dental Implants ◽  
Inductively Coupled Plasma ◽  
Metallic Materials ◽  
In Vitro Degradation ◽  
Inductively Coupled ◽  
Oral Environment ◽  
Plasma Mass Spectrometry ◽  
Materials Used

The bio-tribocorrosion of metallic materials used for dental implants (Ti and alloys) in the oral environment involves the production of metallic debris in the ionic, but also in the nanoparticulated...

scholarly journals The nickel-chelator dimethylglyoxime inhibits human amyloid beta peptide in vitro aggregation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stéphane L. Benoit ◽  
Robert J. Maier
Keyword(s):  
Mass Spectrometry ◽  
Amyloid Beta ◽  
Inductively Coupled Plasma ◽  
Mass Spectrometry Analysis ◽  
Titration Calorimetry ◽  
Aβ Peptides ◽  
Spectrometry Analysis ◽  
Inductively Coupled ◽  
Induced Aggregation

AbstractOne of the hallmarks of the most common neurodegenerative disease, Alzheimer’s disease (AD), is the extracellular deposition and aggregation of Amyloid Beta (Aβ)-peptides in the brain. Previous studies have shown that select metal ions, most specifically copper (Cu) and zinc (Zn) ions, have a synergistic effect on the aggregation of Aβ-peptides. In the present study, inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the metal content of a commercial recombinant human Aβ40 peptide. Cu and Zn were among the metals detected; unexpectedly, nickel (Ni) was one of the most abundant elements. Using a fluorescence-based assay, we found that Aβ40 peptide in vitro aggregation was enhanced by addition of Zn2+ and Ni2+, and Ni2+-induced aggregation was facilitated by acidic conditions. Nickel binding to Aβ40 peptide was confirmed by isothermal titration calorimetry. Addition of the Ni-specific chelator dimethylglyoxime (DMG) inhibited Aβ40 aggregation in absence of added metal, as well as in presence of Cu2+ and Ni2+, but not in presence of Zn2+. Finally, mass spectrometry analysis revealed that DMG can coordinate Cu or Ni, but not Fe, Se or Zn. Taken together, our results indicate that Ni2+ ions enhance, whereas nickel chelation inhibits, Aβ peptide in vitro aggregation. Hence, DMG-mediated Ni-chelation constitutes a promising approach towards inhibiting or slowing down Aβ40 aggregation.

scholarly journals Preclinical Pharmacokinetics and Biodistribution of Anticancer Dinuclear Palladium(II)-Spermine Complex (Pd2Spm) in Mice

2021 ◽  
Vol 14 (2) ◽  
pp. 173
Author(s):  
Martin Vojtek ◽  
Salomé Gonçalves-Monteiro ◽  
Edgar Pinto ◽  
Sára Kalivodová ◽  
Agostinho Almeida ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Half Life ◽  
Inductively Coupled Plasma ◽  
Mammary Glands ◽  
Preclinical Pharmacokinetics ◽  
Inductively Coupled ◽  
Terminal Half Life ◽  
Plasma Mass Spectrometry ◽  
Kidney Liver

Palladium-based compounds are regarded as potential analogs to platinum anticancer drugs with improved properties. The present study assessed the pharmacokinetics and biodistribution of a dinuclear palladium(II)-spermine chelate (Pd2Spm), which has previously been shown to possess promising in vitro activity against several therapy-resistant cancers. Using inductively coupled plasma-mass spectrometry, the kinetic profiles of palladium/platinum in serum, serum ultrafiltrate and tissues (kidney, liver, brain, heart, lungs, ovaries, adipose tissue and mammary glands) were studied in healthy female Balb/c mice after a single intraperitoneal bolus injection of Pd2Spm (3 mg/kg bw) or cisplatin (3.5 mg/kg bw) between 0.5 and 48 h post-injection. Palladium in serum exhibited biphasic kinetics with a terminal half-life of 20.7 h, while the free palladium in serum ultrafiltrate showed a higher terminal half-life than platinum (35.5 versus 31.5 h). Palladium was distributed throughout most of the tissues except for the brain, with the highest values in the kidney, followed by the liver, lungs, ovaries, adipose tissue and mammary glands. The in vitro cellular accumulation was also evaluated in breast cancer cells, evidencing a passive diffusion as a mechanism of Pd2Spm’s cellular entry. This study reports, for the first time, the favorable pharmacokinetics and biodistribution of Pd2Spm, which may become a promising pharmacological agent for cancer treatment.

Biocompatibility of Near-IR Sensitive Au-Based Nanoparticles as the Potential Drug Delivery Carriers

2007 ◽  
Vol 334-335 ◽  
pp. 1177-1180 ◽  
Author(s):  
Bin Zhang ◽  
Xiao Li Huang ◽  
Lei Ren ◽  
Qi Qing Zhang ◽  
Mei Chee Tan ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Near Infrared ◽  
Nih3t3 Cells ◽  
Inductively Coupled ◽  
Near Ir ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Good Biocompatibility

We successfully synthesized near infrared (NIR) sensitive Au(shell)-Au2S(core) nanoparticles, where Au2S dielectric core was encapsulated by a thin gold shell. The cytotoxicity in vitro and biodistribution in vivo of Au-Au2S nanoparticles was studied by using NIH3T3 cells and KM mice, respectively. The quantitative analysis of Au in each tissue of mice was done by using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Au-Au2S nanoparticles (< 300 μg/ml) showed good biocompatibility. Au-Au2S nanoparticles were preferentially taken up by the liver and spleen, and ultimately eliminated mostly in the feces.

scholarly journals Ion Binding Properties of a Naturally Occurring Metalloantibody

Antibodies ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 10
Author(s):  
Elinaz Farokhi ◽  
Jonathan K. Fleming ◽  
M. Frank Erasmus ◽  
Aaron D. Ward ◽  
Yunjin Wu ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Bound State ◽  
Biologically Active ◽  
Titration Calorimetry ◽  
Fab Fragment ◽  
Inductively Coupled ◽  
Flame Atomic Absorption ◽  
Naturally Occurring ◽  
Sphingosine 1 Phosphate ◽  
Plasma Mass Spectrometry

LT1009 is a humanized version of murine LT1002 IgG1 that employs two bridging Ca2+ ions to bind its antigen, the biologically active lipid sphingosine-1-phosphate (S1P). We crystallized and determined the X-ray crystal structure of the LT1009 Fab fragment in 10 mM CaCl2 and found that it binds two Ca2+ in a manner similar to its antigen-bound state. Flame atomic absorption spectroscopy (FAAS) confirmed that murine LT1002 also binds Ca2+ in solution and inductively-coupled plasma-mass spectrometry (ICP-MS) revealed that, although Ca2+ is preferred, LT1002 can bind Mg2+ and, to much lesser extent, Ba2+. Isothermal titration calorimetry (ITC) indicated that LT1002 binds two Ca2+ ions endothermically with a measured dissociation constant (KD) of 171 μM. Protein and genome sequence analyses suggested that LT1002 is representative of a small class of confirmed and potential metalloantibodies and that Ca2+ binding is likely encoded for in germline variable chain genes. To test this hypothesis, we engineered, expressed, and purified a Fab fragment consisting of naïve murine germline-encoded light and heavy chain genes from which LT1002 is derived and observed that it binds Ca2+ in solution. We propose that LT1002 is representative of a class of naturally occurring metalloantibodies that are evolutionarily conserved across diverse mammalian genomes.

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