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Soluble TREM2 inhibits secondary nucleation of Aβ fibrillization and enhances cellular uptake of fibrillar Aβ

ABSTRACT: We used sTREM2 obtained from bacterial expression system to form a complex with Aβ40 fibrils in vitro. This complex was chemically cross-linked using two cross-linkers, BS3 and NHSF.

ORGANISM(S): Escherichia Coli

SUBMITTER: Bill DeGrado

PROVIDER: PXD030722 | iProX | Wed Jan 05 00:00:00 GMT 2022

REPOSITORIES: iProX

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Soluble TREM2 inhibits secondary nucleation of Aβ fibrillization and enhances cellular uptake of fibrillar Aβ.

Belsare Ketaki D KD Wu Haifan H Mondal Dibyendu D Bond Annalise A Castillo Erika E Jin Jia J Jo Hyunil H Roush Addison E AE Pilla Kala Bharath KB Sali Andrej A Condello Carlo C DeGrado William F WF

Proceedings of the National Academy of Sciences of the United States of America 20220201 5

Triggering receptor expressed on myeloid cells 2 (TREM2) is a single-pass transmembrane receptor of the immunoglobulin superfamily that is secreted in a soluble (sTREM2) form. Mutations in TREM2 have been linked to increased risk of Alzheimer's disease (AD). A prominent neuropathological component of AD is deposition of the amyloid-β (Aβ) into plaques, particularly Aβ40 and Aβ42. While the membrane-bound form of TREM2 is known to facilitate uptake of Aβ fibrils and the polarization of microglial ...[more]

PMID: 35082148

Similar Datasets

Soluble TREM2 inhibits secondary nucleation of Aβ fibrillization and enhances cellular uptake of fibrillar Aβ.

Project description:Triggering receptor expressed on myeloid cells 2 (TREM2) is a single-pass transmembrane receptor of the immunoglobulin superfamily that is secreted in a soluble (sTREM2) form. Mutations in TREM2 have been linked to increased risk of Alzheimer's disease (AD). A prominent neuropathological component of AD is deposition of the amyloid-β (Aβ) into plaques, particularly Aβ40 and Aβ42. While the membrane-bound form of TREM2 is known to facilitate uptake of Aβ fibrils and the polarization of microglial processes toward amyloid plaques, the role of its soluble ectodomain, particularly in interactions with monomeric or fibrillar Aβ, has been less clear. Our results demonstrate that sTREM2 does not bind to monomeric Aβ40 and Aβ42, even at a high micromolar concentration, while it does bind to fibrillar Aβ42 and Aβ40 with equal affinities (2.6 ± 0.3 µM and 2.3 ± 0.4 µM). Kinetic analysis shows that sTREM2 inhibits the secondary nucleation step in the fibrillization of Aβ, while having little effect on the primary nucleation pathway. Furthermore, binding of sTREM2 to fibrils markedly enhanced uptake of fibrils into human microglial and neuroglioma derived cell lines. The disease-associated sTREM2 mutant, R47H, displayed little to no effect on fibril nucleation and binding, but it decreased uptake and functional responses markedly. We also probed the structure of the WT sTREM2-Aβ fibril complex using integrative molecular modeling based primarily on the cross-linking mass spectrometry data. The model shows that sTREM2 binds fibrils along one face of the structure, leaving a second, mutation-sensitive site free to mediate cellular binding and uptake.

| S-EPMC8812518 | biostudies-literature

Real-time library search assisted identification of cross-links increases resolution for structural modeling and interactome mapping

Project description:Cross-linking mass spectrometry (XL-MS) is a universal tool of molecular and structural biology for probing structural dynamics and protein-protein interactions in vitro and in vivo. Although cross-linked peptides are naturally less abundant than their unlinked counterparts, recent experimental advances improved cross-link identification by enriching the cross-linker modified peptides chemically with the use of enrichable cross-linkers. However, mono-links (i.e., peptides modified with a hydrolyzed cross-linker) still hinder efficient cross-link identification because a large proportion of measurement time is spent on MS2 acquisitions of mono-links. Currently, cross-links and mono-links cannot be separated by sample preparation techniques or chromatography because they are chemically almost identical. Here, we found that based on the intensity ratios of four diagnostic peaks when using PhoX/tert-butyl-PhoX cross-linkers, cross-links and mono-links can be partially distinguished. Harnessing their characteristic intensity ratios for real-time library search (RTLS)-based triggering of full scans increased the number of cross-link identifications from both single protein samples and intact E. coli cells. Furthermore, RTLS improves cross-link identification from unenriched samples and short gradients, which is beneficial in high-throughput approaches and when instrument time or sample amount is limited.

2023-03-20 | PXD037652 | Pride

TRPV4 enhances the cellular uptake of aminoglycoside antibiotics.

Project description:The cochlea and kidney are susceptible to aminoglycoside-induced toxicity. The non-selective cation channel TRPV4 is expressed in kidney distal tubule cells, and hair cells and the stria vascularis in the inner ear. To determine whether TRPV4 is involved in aminoglycoside trafficking, we generated a murine proximal-tubule cell line (KPT2) and a distal-tubule cell line (KDT3). TRPV4 expression was confirmed in KDT3 cells but not in KPT2 cells. Removal of extracellular Ca(2+) significantly enhanced gentamicin-Texas-Red (GTTR) uptake by KDT3, indicative of permeation through non-selective cation channels. To determine whether TRPV4 is permeable to GTTR, stable cell lines were generated that express TRPV4 in KPT2 (KPT2-TRPV4). KPT2-TRPV4 cells took up more GTTR than control cell lines (KPT2-pBabe) in the absence of extracellular Ca(2+). TRPV4-dependent GTTR uptake was abolished by a point mutation within the crucial pore region of the channel, suggesting that GTTR permeates the TRPV4 channel. In an endolymph-like extracellular environment, clearance of GTTR was attenuated from KPT2-TRPV4 cells in a TRPV4-dependent fashion. We propose that TRPV4 has a role in aminoglycoside uptake and retention in the cochlea.

| S-EPMC2736053 | biostudies-literature

The S/T/Y-linked residue pairs identified by current software are unreliable

Project description:Here, by setting amino acids with chemically inert side chains such as glycine (G), valine (V), and leucine (L) as cross-linkable sites, which serves as a negative control, we show that the identifications of S/T/Y-linked peptides are as reliable as those of G/V/L-linked peptides. This is true across different NHS ester cross-linkers including DSS, DSSO, and DSBU, and across different search engines including MeroX, xiSearch, and pLink.

2022-12-26 | PXD039103 | iProX

Sodium-glucose transporter-2 (SGLT2; SLC5A2) enhances cellular uptake of aminoglycosides.

Project description:Aminoglycoside antibiotics, like gentamicin, continue to be clinically essential worldwide to treat life-threatening bacterial infections. Yet, the ototoxic and nephrotoxic side-effects of these drugs remain serious complications. A major site of gentamicin uptake and toxicity resides within kidney proximal tubules that also heavily express electrogenic sodium-glucose transporter-2 (SGLT2; SLC5A2) in vivo. We hypothesized that SGLT2 traffics gentamicin, and promotes cellular toxicity. We confirmed in vitro expression of SGLT2 in proximal tubule-derived KPT2 cells, and absence in distal tubule-derived KDT3 cells. D-glucose competitively decreased the uptake of 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), a fluorescent analog of glucose, and fluorescently-tagged gentamicin (GTTR) by KPT2 cells. Phlorizin, an SGLT2 antagonist, strongly inhibited uptake of 2-NBDG and GTTR by KPT2 cells in a dose- and time-dependent manner. GTTR uptake was elevated in KDT3 cells transfected with SGLT2 (compared to controls); and this enhanced uptake was attenuated by phlorizin. Knock-down of SGLT2 expression by siRNA reduced gentamicin-induced cytotoxicity. In vivo, SGLT2 was robustly expressed in kidney proximal tubule cells of heterozygous, but not null, mice. Phlorizin decreased GTTR uptake by kidney proximal tubule cells in Sglt2+/- mice, but not in Sglt2-/- mice. However, serum GTTR levels were elevated in Sglt2-/- mice compared to Sglt2+/- mice, and in phlorizin-treated Sglt2+/- mice compared to vehicle-treated Sglt2+/- mice. Loss of SGLT2 function by antagonism or by gene deletion did not affect gentamicin cochlear loading or auditory function. Phlorizin did not protect wild-type mice from kanamycin-induced ototoxicity. We conclude that SGLT2 can traffic gentamicin and contribute to gentamicin-induced cytotoxicity.

| S-EPMC4182564 | biostudies-literature

3-O-Sulfation of Heparan Sulfate Enhances Tau Interaction and Cellular Uptake.

Project description:Prion-like transcellular spreading of tau in Alzheimer's Disease (AD) is mediated by tau binding to cell surface heparan sulfate (HS). However, the structural determinants for tau-HS interaction are not well understood. Microarray and SPR assays of structurally defined HS oligosaccharides show that a rare 3-O-sulfation (3-O-S) of HS significantly enhances tau binding. In Hs3st1-/- (HS 3-O-sulfotransferase-1 knockout) cells, reduced 3-O-S levels of HS diminished both cell surface binding and internalization of tau. In a cell culture, the addition of a 3-O-S HS 12-mer reduced both tau cell surface binding and cellular uptake. NMR titrations mapped 3-O-S binding sites to the microtubule binding repeat 2 (R2) and proline-rich region 2 (PRR2) of tau. Tau is only the seventh protein currently known to recognize HS 3-O-sulfation. Our work demonstrates that this rare 3-O-sulfation enhances tau-HS binding and likely the transcellular spread of tau, providing a novel target for disease-modifying treatment of AD and other tauopathies.

| S-EPMC6982596 | biostudies-literature

The Nitric Oxide Prodrug V-PROLI/NO Inhibits Cellular Uptake of Proline.

Project description:V-PYRRO/NO is a well studied nitric oxide (NO) prodrug which has been shown to protect human liver cells from arsenic, acetaminophen, and other toxic assaults in vivo. Its proline-based analogue, V-PROLI/NO, was designed to be a more biocompatible form that decomposes to the naturally occurring metabolites of proline, NO, and glycolaldehyde. Like V-PYRRO/NO, this cytochrome P450-activated prodrug was previously assumed to passively diffuse through the cellular membrane. Using (14)C-labeled proline in a competition assay, we show that V-PROLI/NO is transported through proline transporters into multiple cell lines. A fluorescent NO-sensitive dye (DAF-FM diacetate) and nitrite excretion indicated elevated intracellular NO release after metabolism over V-PYRRO/NO. These results also allowed us to predict and design a more permeable analogue, V-SARCO/NO. We report a proline transporter-based strategy for the selective transport of NO prodrugs that may have enhanced efficacy and aid in development of further NO prodrugs with increased permeability.

| S-EPMC3013513 | biostudies-literature

A Carrier-Free Nanostructure Based on Platinum(IV) Prodrug Enhances Cellular Uptake and Cytotoxicity.

Project description:Flurbiprofen, a hydrophobic COX inhibitor, was coordinated axially with oxoplatin to form a new conjugate, cis, cis, trans-[Pt(IV)(NH3)2Cl2(flurbiprofen)2]. The successful synthesis of this new conjugate was confirmed by 1H, 13C, and 195Pt NMR. The potential of this conjugate being reduced to cisplatin and subsequently exerting its DNA cross-linking ability was verified using cyclic voltammetry (CV), HPLC, and mass spectrometry (MS). This conjugate showed markedly higher cytotoxicity on many cancer cell lines than cisplatin, flurbiprofen, and their physical mixture (mole ratio, cisplatin:flurbiprofen = 1:2). This is consistent with the result of an apoptosis-inducing assay. This conjugate spontaneously assembles carrier-free nanoparticles in aqueous solution, which is confirmed by DLS, TEM, SEM, and AFM, and thus facilitates cellular uptake and markedly improves its cytotoxicity and apoptosis-inducing ability in vitro.

| S-EPMC7057395 | biostudies-literature

Improving Mass Spectrometry Analysis of Protein Structures with Arginine-Selective Chemical Cross-linkers

Project description:we develop a series of arginine selective bifunctional aromatic glyoxal cross-linkers (ArGOs) and demonstrate their ability to cross-link model proteins and a protein complex. We also introduce the first arginine-lysine heterobifunctional cross-linker (KArGO), which provides significantly greater surface coverage than the corresponding homobifunctional reagents (e.g. ArGOs and BS3), due to access to the combined abundances of lysine and arginine residues.

2019-01-14 | PXD012341 | iProX

Transcription profiling by array to assess epidemic methicillin-resistant Staphylococcus aureus 16 phenotypes induced by PBD conjugates

Project description:Objectives Pyrrolobenzodiazepine (PBD) dimers, tethered through inert propyldioxy or pentyldioxy linkers, possess potent bactericidal activity against a range of Gram-positive bacteria by virtue of their capacity to cross-link duplex DNA in sequence-selective fashion. Here we attempt to improve the antibacterial activity and cytotoxicity profile of PBD-containing conjugates by extension of dimer linkers and replacement of one PBD unit with phenyl-substituted or benzo-fused heterocycles that facilitate non-covalent interactions with duplex DNA. Methods DNase I footprinting was used to identify high-affinity DNA binding sites. A staphylococcal gene microarray was used to assess epidemic methicillin-resistant Staphylococcus aureus 16 phenotypes induced by PBD conjugates. Molecular dynamics simulations were employed to investigate the accommodation of compounds within the DNA helix. Results Increasing the length of the linker in PBD dimers led to a progressive reduction in antibacterial activity, but not in their cytotoxic capacity. Complex patterns of DNA binding were noted for extended PBD dimers. Modelling of DNA strand cross-linking by PBD dimers indicated distortion of the helix. A majority (26 of 43) of PBD-biaryl conjugates possessed potent antibacterial activity with little or no helical distortion and a more favourable cytotoxicity profile. Bactericidal activity of PBD-biaryl conjugates was determined by inability to excise covalently bound drug molecules from bacterial duplex DNA. Conclusions PBD-biaryl conjugates have a superior antibacterial profile compared with PBD dimers such as ELB-21. We have identified six PBD-biaryl conjugates as potential drug development candidates. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-118]

2012-04-17 | E-BUGS-118 | biostudies-arrayexpress

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