Skip to main content
NCBI home page
ACS Medicinal Chemistry Letters logoLink to ACS Medicinal Chemistry Letters
. 2020 Aug 11;11(9):1759–1765. doi: 10.1021/acsmedchemlett.0c00330

Quinoline-Pyrazole Scaffold as a Novel Ligand of Galectin-3 and Suppressor of TREM2 Signaling

Moustafa Gabr †,*, Ashfaq Ur Rehman ‡,§, Hai-Feng Chen §,∥
PMCID: PMC7488289  PMID: 32944144

Abstract

graphic file with name ml0c00330_0009.jpg

Galectin-3 has been identified as a critical player in driving the neuroinflammatory responses in Alzheimer’s disease (AD). A key feature of this function of galectin-3 is associated with its interaction with the triggering receptor expressed on myeloid cells-2 (TREM2). Herein, we report a high-throughput screening (HTS) platform that can be used for the identification of inhibitors of TREM2 and galectin-3 interaction. We have utilized this HTS assay to screen a focused library of compounds optimized for the central nervous system (CNS)-related diseases. MG-257 was identified from this screen as the first example of a small molecule that can attenuate TREM2 signaling based on its high affinity to galectin-3 (endogenous ligand of TREM2). Remarkably, MG-257 reduced the levels of proinflammatory cytokines in activated microglial cells, which highlights its ability to inhibit the neuroinflammatory response associated with AD.

Keywords: Galectin-3, neurological disorders, FRET assay, neuroinflammation, Alzheimer’s disease

Galectin-3 is an ∼30 kDa protein expressed in the human body that functions as β-galactoside-binding lectin through a carbohydrate recognition domain (CRD).1−3 In the human body, galectin-3 is widely expressed in different immune cells, including monocytes, macrophages, activated T cells, endothelial cells, dendritic cells, and sensory neurons.4−6 Galectin-3 exerts a fundamental function in the regulation of cell–cell interactions and consequently impacts cell proliferation and differentiation.7 Variations in the expression of galectin-3 and cellular localization have been attributed to different types of cancer.8−11 Additionally, galectin-3 has active roles in tumor transformation, apoptosis regulation, cancer metastasis, and cancer cell adhesion.12−14 Therefore, significant research efforts have been directed toward the identification of galectin-3 inhibitors as potential anticancer drug candidates.15−18 Moreover, galectin-3 is involved in monocyte–macrophage differentiation and inhibition of B-lymphocyte differentiation.19,20 Myocardial galectin-3 has been recently identified as a potential biomarker for cardiovascular diseases.21 Modulation of galectin-3 activity has been proposed as a therapeutic strategy for cardiovascular diseases.22,23

Alzheimer’s disease (AD) is the leading cause of dementia worldwide.24,25 Triggering receptor expressed on myeloid cells 2 (TREM2) is a protein that is expressed in the human brain and plays key roles in the regulation of microglial functions associated with pathologies related to neurological disorders.26−28 High levels of TREM2 have been detected in plaque-associated microglia in human AD brain.29 Multifaceted roles have been proposed for the association of TREM2 with AD such as regulating amyloid-beta (Aβ) pathology, tau hyperphosphorylation, tau aggregation, and microgliosis.30−32 Additionally, an association between rare TREM2 variants such as T96K, D87N, and R62H and AD development has been establishment.33 Therefore, TREM2 has evolved as a potential therapeutic target for AD.34

Recently, galectin-3 has been identified as an endogenous TREM2 ligand with a key regulatory role in the neuroinflammatory response associated with AD progression.35 Improved cognitive behavior and reduced Aβ burden upon galectin-3 knockout in a mice model of AD further highlights the implication of galectin-3 in AD progression.35 Colocalization of TREM2 and galectin-3 in microglial processes has been demonstrated by high-resolution microscopy.35 Additionally, TREM2 signaling was stimulated in response to galectin-3 activation in a reporter cell line.35 The involvement of galectin-3 in AD pathology has been further confirmed by its ability to promote Aβ aggregation and toxicity in vivo.36 Remarkably, Aβ aggregation is linked to increased galectin-3 expression in the frontal lobe of AD patients.36 Such effect is attributed to the ability of galectin-3 to upregulate the microglial immune activity by driving proinflammatory fibrillar Aβ-associated immune responses that impede Aβ clearance. Therefore, targeting galectin-3 and its interaction with TREM2 have evolved as a novel pathway for the development of potential AD therapeutics.35 However, small molecules targeting galectin-3 with potential as AD therapeutics have not been previously reported.

The majority of galectin-3 inhibitors are carbohydrate-based molecules with limited penetration ability of the central nervous system (CNS) and undesirable pharmacokinetic profiles as CNS therapeutics.37−41 Importantly, cellular uptake and distribution of galectin-3 inhibitors have been proven to be crucial for their inhibitory galectin-3 function.42 Thus, it is crucial to identify small molecules with desirable pharmacokinetic profiles for CNS-related diseases as galectin-3 inhibitors. Additionally, galectin-3 inhibitors that can impede the interaction between galectin-3 and TREM2 would hold promise for further optimization as AD therapeutics.

Aiming to identify small molecules that can interrupt galectin-3 interaction with TREM2, we developed a time-resolved fluorescence resonance energy transfer (TR-FRET) assay utilizing the affinity of galectin-3 to TREM2. We further optimized the developed TR-FRET assay for high-throughput screening (HTS), which would enable screening chemical libraries. The validity of the assay for HTS has been demonstrated with a mean Z’ factor of 0.75 (see Supporting Information), revealing a high-quality assay for HTS. The Z’ factor corresponds to the ratio of data signal variability (standard deviation) to dynamic range (i.e., change in TR-FRET signal for positive and negative controls).43 Europium (Eu) cryptate and Alexa Fluor 647 dye are two luminophores with overlapping emission and excitation spectra, which have enabled their employment in TR-FRET assays.44 We have labeled galectin-3 and TREM2 with Eu cryptate and Alexa Fluor 647, respectively. Thus, Eu cryptate-labeled galectin-3 would function as the donor, and Alexa Fluor 647-labeled TREM2 would function as the acceptor in the TR-FRET assay. Small molecules that can bind galectin-3 would impede its interaction with TREM2 and consequently result in attenuated TR-FRET signal (Figure 1). A linear relationship between the acceptor:donor ratio and TR-FRET ratio is demonstrated (Figure 2). Moreover, a decrease in the TR-FRET ratio was detected upon incubation with the galectin-3 antibody in a dose-dependent manner (Figure S1).

Figure 1.

Figure 1

Open in a new tab

Schematic representation of the developed TR-FRET assay to identify inhibitors of the interaction between TREM2 and galectin-3. A FRET signal is detected upon the interaction of galectin-3 with TREM2. However, the binding of small molecules to galectin-3 will inhibit the interaction and result in decreased FRET signal.

Figure 2.

Figure 2

Open in a new tab

Titration of Alexa Fluor 647-labeled TREM2 (acceptor) to Eu-labeled galectin-3 (donor) illustrates FRET efficiency based on hyperbolic dependence on acceptor concentration. Error bars represent standard deviation (n = 3).

Chemical libraries from commercial sources that are optimized for CNS penetration (∼1,300 compounds) were screened using the developed assay at a single-dose screen (10 μM). Hits were identified by the ability to decrease the TR-FRET signal by more than 5 standard deviations (5 SD) lower than the total mean. MG-257 (Figure 3A) exhibited remarkable attenuation of the TR-FRET signal (>95%) in comparison to the identified hits. Dose-dependent FRET screening was conducted for MG-257, which revealed a half-maximal inhibitory concentration (IC50) value of 91 ± 5.7 nM (Figure 3B). Fluorescence anisotropy (FA) assay is well established for determining the binding affinity of small molecules to galectins.45 In brief, elevated concentrations of galectin are incubated with a single concentration of tested small molecule, which results in an increase of anisotropy value to (Amax), which corresponds to binding saturation.45 The dissociation constant (Kd) between MG-257 and galectin-3 using FA assay was determined to be 0.15 ± 0.02 μM. Remarkably, the Kd value for the interaction between galectin-1 and MG-257 was >500 μM which indicates the high selectivity of MG-257 to galectin-3. Surface plasmon resonance (SPR) analysis was utilized to investigate the interaction between galectin-3 and MG-257. Initially, galectin-3 was immobilized on a sensor chip via amine coupling, followed by flowing increasing concentrations of MG-257 on the chip, which resulted in a gradual increase in response units (RU). The estimated Kd for MG-257 to galectin-3 based on SPR analysis was determined to be 0.29 ± 0.05 μM (Figure S2). Remarkably, SPR analysis revealed a minimal binding affinity of MG-257 to TREM2. Therefore, the inhibitory effect of MG-257 in the TR-FRET assay is associated with directing interaction with galectin-3 rather than TREM2. Thus, the high affinity of MG-257 to galectin-3 has been demonstrated through biorthogonal assays. Spectral analysis of MG-257 was in good agreement with the literature.46,47 Moreover, HPLC analysis indicated that the purity of MG-257 was above 99% (Figure S3).

Figure 3.

Figure 3

Open in a new tab

(A) Chemical structure of MG-257. (B) Dose–response curves of MG-257 binding in a TR-FRET assay. Error bars represent standard deviation (n = 3).

The binding mechanism of β-galactosides to galectins is due to CRD, where glycan-binding occurs.48,49 Unlike members of the galectin family, galectin-3 possesses CRD at the C-terminus.49 CRD folds into two antiparallel sheets of six (S1–S6) and five (F1–F5) strands which constitute a β-sheet sandwich structure (Figure 4). To discuss in detail the binding interaction of MG-257 with galectin-3, we have performed molecular docking and extensive molecular dynamics (MD) simulation using the AMBER software package in an explicit watery environment.

Figure 4.

Figure 4

Open in a new tab

Overview of the gelatin-3 protein structure. Site-1 is the original site for glycan-binding; in our study, we docked the MG-257 molecule. Site-2 is the temporary site, where the overall skeleton of the MG-257 molecule bonded except the iso-quinoline moiety, which tightly bonded in site-1. (a) indicates the 3D interaction mode of the MG-257 molecule, while (b) indicates the 2D interaction.

The outcome of the molecular docking study revealed a fit-well binding pattern by MG-257 through adopting fundamental interactions with active site residues, including Trp181 (phi-stacking) with the iso-quinoline moiety and Glu184 (H-bond) with the 1-methyl-2,3-dihydro-1H-pyrazole moiety of the MG-257 molecule (Figure 4). Furthermore, the MD simulation study was conducted to illustrate the stability of the MG-257 complex with galectin-3 protein in an explicit watery environment. Generally, it was observed that the iso-quinoline moiety of MG-257 remains stuck in the active site, while the other moieties change the residues’ interaction with active site residues. This way, we identified two sites (site-1 (original site) and site-2) in the CRD, where MG-257 had a high affinity, as shown in Figure 4. For ease of clarification and support of dynamics results, we further analyzed the dynamics trajectory.

The deviation of backbone atoms was studied by root-mean-square-deviation (RMSd). The RMSd of both systems in comparison to original structures indicates that MD simulation for 100 ns is sufficient to achieve equilibration at 310 K. A low RMSd curve reveals high stability of the conformation and vice versa.50 A stabilized behavior in the presence of the MG-257 molecule in comparison to its absence is evident from the variation in RMSd results (Figure 5A). From 0 to 100 ns, the RMSd curve for in the absence revealed a high fluctuation. In contrast, this fluctuation remains stabilized in the MG-257 bound system, which indicates the stabilized behaviors of the overall conformation of the complex and consequently minimal interaction with the other protein. Furthermore, frequency distribution counts of RMSd were determined to examine the variation of conformational changes among them (Figure 5B). In the absence of the MG-257 molecule, RMSd is less consistent and less stable. In contrast, for the MG-257 molecule bound system, high stable behavior and more consistency are observed (Figure 5B).

Figure 5.

Figure 5

Open in a new tab

(A) Illustration of the root-mean-square-deviation (RMSd) graph of both systems, in both the absence and presence of the MG-257 molecule during the 100 ns of MD simulation time. (B) Distributional frequency counts of RMSd calculated throughout the 100 ns plotted, showing consistent and nonconsistent behavior in the absence and presence of the MG-257 molecule; higher RMSd indicates lower stability and vice versa. (C) Superpose root-mean-square-fluctuation (RMSf) graph for in both the absence and presence of the MG-257 molecule; both sites are labeled.

Moreover, to elucidate the fluctuation of individual residues in both systems, we examined the root-mean-square-fluctuations (RMSf), which give insight on the flexibility of each residue. The coordinates of both systems were aligned, and the average structure for each state was utilized as a reference to calculate residue fluctuation. The RMSf results demonstrate a very stabilized behavior, notably, in the site, where the MG-257 molecule bonded; also, we observed that MG-257 molecule binding brings a stabilization behavior in the nearby residues, where we exemplified it by site-2. Overall, the RMSf results revealed that the binding of the MG-257 molecule stabilized the overall conformation of the protein (Figure 5C).

To clarify the specificity of MG-257 molecule bonding in the active site dynamically, we analyzed the carbon-alpha (CA)-distance analysis of active site residues with this molecule. The results revealed that initially (1 ns–17 ns), this molecule was found away from the active site except for the isoquinoline moiety. Afterward, the CA-distance among the protein active site and this molecule oscillated until 100 ns of MD simulation time. The initial away mode of this molecule was clarified by extracting the conformations from 0 to 17 ns, to check the conformational changes and binding mode. We observed that the overall molecule except for the isoquinoline moiety of MG-257 resides in the site, exemplified as site-2, and, afterward, remains tightly bonded in site-1, which is the original binding site (Figure 6A). Also, these results were further evaluated by the clustering analysis of the overall MD trajectory. The conformation was extracted per nanosecond (ns) and then clustered into a single. Second, we measured the center-of-mass (COM) of MG-257, as enlisted in Table S1 using the PyMol visualizing tool. The results revealed and supported the CA-distance analysis that the MG-257 molecules most of the time clustered into site-1 (90%) rather than in site-2 which is 6%; also we found that this molecule for 1.5% clustered in the middle of these two sites (Figure 6B). These results are evident in the stickiness of the MG-257 molecule and give a clue regarding the actual binding mode in site-1 rather than a temporary site. Each sphere indicates a single MG-257 molecule (Figure 6B).

Figure 6.

Figure 6

Open in a new tab

Dynamic CA-distance (D) and dynamics-cross-correlation-map (DCCM) analysis. (A) Blue transparent color indicates the bonding of MG-257 with site-2 residues while remaining stable in site-01 afterward. (B) represents the overall trajectory of superposed clusters (cartoon), during MD simulation. Each sphere represents ligand (MG-257); the calculation is done based on the center-of-mass (COM) of a ligand. (C–D) indicate the residues’ displacement, the red color indicates the correlation, while blue color indicates the anticorrelation. In the absence of the MG-257 molecule, site-1 occupied the anticorrelation, which indicates the free movement of side-chain residues. In contrast, this free movement stabilized and swapped into correlation by binding of the MG-257 molecule.

To study the displacements of gelatin-3 protein atoms as a function of time, dynamic cross-correlation matrix (DCCM) analysis was performed. Quantification of the relative motion of residues using DCCM analysis elucidates their relationships with distinct regions. Displacement in the same direction is associated with positive values, whereas different displacements result in negative values (Figures 6C–D). The results revealed a moderate anticorrelation overall, particularly in the active site region in the absence of the MG-257 molecule, but this anticorrelation swaps into correlation motion, when MG-257 bonded to this region. Also, the binding of this molecule brings dramatic conformation displacement in the overall system. In the absence of this molecule, the overall conformation remains anticorrelated, while it is correlated in the presence. These results delineate that MG-257 molecule binding stabilized the overall conformation of the gelatin-3 protein and rescued them from intramolecular interaction with other proteins.

The involvement of galectin-3 in regulating amyloid-dependent microglial activation has been previously demonstrated.35 Challenging BV2 cells with microglial cells activated using Aβ fibrils results in elevated expression of proinflammatory cytokines and inducible nitric oxide synthase (iNOS).35 To evaluate the galectin-3 inhibitory activity of MG-257 in a cellular platform, we incubated Aβ fibrils (10 μM) with BV2 microglial cells which resulted in elevated levels of proinflammatory cytokines (tumor necrosis factor-alpha (TNFα), interleukin 12 (IL12), and interleukin 8 (IL8)) as shown in Figure 7. Remarkably, coincubation with increasing concentrations of MG-257 resulted in a dose-dependent reduction in the released proinflammatory cytokines (Figures 7A–C). For example, TNFα levels have been reduced by ∼50% in the presence of 10 μM of MG-257 (Figure 7A). Additionally, the coincubation of MG-257 (10 μM) with BV2 microglial cells resulted in ∼40% reduction in IL12 levels (Figure 7B). Therefore, MG-257 can impede neuroinflammation triggered by Aβ aggregates and consequently would potentially be critical in enhancing Aβ clearance.

Figure 7.

Figure 7

Open in a new tab

Reduced cytokine levels in the culture medium of BV2 cells coincubated with Αβ fibrils (10 μΜ) for 12 h in the absence and presence of various concentrations of MG-257. Error bars represent standard deviation (n = 3). (*p < 0.05; **p < 0.005 relative to untreated control).

DAP12 is a transmembrane protein that is identified as a critical signal transduction receptor in natural killer (NK) cells.35 TREM2 signaling in response to galectin-3 activation is mediated through DAP12 based on a TREM2-DAP12 reporter cell line assay.35 The assay is based on BWZ thymoma cells transfected with TREM2 and DAP12. Phospholipase C is activated because of TREM2/DAP12 signaling, which triggers calcium influx and activation of nuclear transport of NFAT (nuclear factor of activated T-cells). As a result, the transcription of LacZ β-galactosidase gene is induced. Evaluation of the outcome of the coincubation of MG-257 in the TREM2-DAP12 reporter cell line in the presence of galectin (5 μM) as a stimulant revealed its ability to decrease TREM2 signaling in a dose-dependent manner (Figure 8). Incubation of MG-257 with BWZ cells without TREM2 and DAP12 transfection revealed negligible change in LacZ activity highlighting the dependence of MG-257 activity on TREM2 signaling (Figure S4). These results come in good agreement with the ability of MG-257 to impede the interaction between TREM2 and galectin-3 using the TR-FRET assay reported in this study. Therefore, MG-257 holds promise as an inhibitor of TREM2 signaling a new therapeutic strategy for AD.

Figure 8.

Figure 8

Open in a new tab

Measurement of LacZ activity in the DAP12 reporter cell line stimulated with galectin-3 (5 μM) in the absence and presence of various concentrations of MG-257. Error bars represent standard deviation (n = 3). −ve control denotes cells untreated with galectin-3, and +ve control denotes cells incubated with galectin-3 in the absence of MG-257 (*p < 0.05 relative to untreated control).

The suitability of the identified compound (MG-257) for CNS-related diseases was preliminarily examined by evaluating its ability to cross the blood–brain barrier (BBB) using parallel artificial membrane permeability assay for the BBB (PAMPA-BBB). A permeability (Pe) value of 34.5 × 10–6 cm/s for MG-257 indicates its likelihood to penetrate the BBB in comparison to donepezil and caffeine as controls (Table S2). Preliminary pharmacokinetic profiling of MG-257 is demonstrated in Table S3. The stability of MG-257 in simulated body fluids, as well as its metabolic stability, indicates its suitability for in vivo testing. Additionally, the lipid permeability and low toxicity of MG-257 further demonstrate desirable pharmacokinetic profiling as a lead for further optimization studies.

In summary, we have developed a TR-FRET assay that can be used to identify small molecules that can inhibit the interaction between galectin-3 and TREM2. HTS of a focused chemical library using this assay identified MG-257 as the first small molecule with the ability to impede TREM2–galectin-3 interaction. The submicromolar affinity of MG-257 to galectin-3 has been confirmed using the FRET assay, SPR analysis, and the FA assay. Preliminary in vitro evaluation of MG-257 revealed its ability to reduce proinflammatory cytokines production in response to galectin-3 activation. Additionally, MG-257 impedes TREM2/DAP12 signaling as demonstrated by a DAP12 reporter cell line model. Further structural modifications of MG-257 will enable the development of a new generation of potential AD therapeutics that function via targeting galectin-3.

Glossary

Abbreviations

TREM2

triggering receptor expressed on myeloid cells-2

AD

Alzheimer’s disease

HTS

high-throughput screening

FRET

fluorescence resonance energy transfer

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsmedchemlett.0c00330.

  • Experimental procedures, HTS optimization, cellular assays, and computational studies (PDF)

Author Contributions

The manuscript was written through the contributions of all authors.

The authors declare no competing financial interest.

Supplementary Material

ml0c00330_si_001.pdf (300.3KB, pdf)

References

  1. Argüeso P.; Panjwani N. Focus on molecules: galectin-3. Exp. Eye Res. 2011, 92 (1), 2–3. 10.1016/j.exer.2010.11.009. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Dumic J.; Dabelic S.; Flögel M. Galectin-3: an open-ended story. Biochim. Biophys. Acta, Gen. Subj. 2006, 1760 (4), 616–35. 10.1016/j.bbagen.2005.12.020. [DOI] [PubMed] [Google Scholar]
  3. Dong R.; Zhang M.; Hu Q.; Zheng S.; Soh A.; Zheng Y.; Yuan H. Galectin-3 as a novel biomarker for disease diagnosis and a target for therapy (Review). Int. J. Mol. Med. 2018, 41 (2), 599–614. 10.3892/ijmm.2017.3311. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Newlaczyl A. U.; Yu L. G. Galectin-3--a jack-of-all-trades in cancer. Cancer Lett. 2011, 313 (2), 123–8. 10.1016/j.canlet.2011.09.003. [DOI] [PubMed] [Google Scholar]
  5. Liu F. T.; Hsu D. K.; Zuberi R. I.; Kuwabara I.; Chi E. Y.; Henderson W. R. Jr. Expression and function of galectin-3, a beta-galactoside-binding lectin, in human monocytes and macrophages. Am. J. Pathol. 1995, 147 (4), 1016–1028. [PMC free article] [PubMed] [Google Scholar]
  6. de Oliveira F. L.; Gatto M.; Bassi N.; Luisetto R.; Ghirardello A.; Punzi L.; Doria A. Galectin-3 in autoimmunity and autoimmune diseases. Exp. Biol. Med. (London, U. K.) 2015, 240 (8), 1019–1028. 10.1177/1535370215593826. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Argüeso P.; Mauris J.; Uchino Y. Galectin-3 as a regulator of the epithelial junction: Implications to wound repair and cancer. Tissue Barriers 2015, 3 (3), e1026505 10.1080/21688370.2015.1026505. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Ruvolo P. P. Galectin 3 as a guardian of the tumor microenvironment. Biochim. Biophys. Acta, Mol. Cell Res. 2016, 1863 (3), 427–437. 10.1016/j.bbamcr.2015.08.008. [DOI] [PubMed] [Google Scholar]
  9. Okada K.; Shimura T.; Suehiro T.; Mochiki E.; Kuwano H. Reduced galectin-3 expression is an indicator of unfavorable prognosis in gastric cancer. Anticancer Res. 2006, 26, 1369–1376. [PubMed] [Google Scholar]
  10. Song L.; Tang J. W.; Owusu L.; Sun M. Z.; Wu J.; Zhang J. Galectin-3 in cancer. Clin. Chim. Acta 2014, 431, 185–91. 10.1016/j.cca.2014.01.019. [DOI] [PubMed] [Google Scholar]
  11. Wang Y.; Liu S.; Tian Y.; Wang Y.; Zhang Q.; Zhou X.; Meng X.; Song N. Prognostic role of galectin-3 expression in patients with solid tumors: a meta-analysis of 36 eligible studies. Cancer Cell Int. 2018, 18 (1), 172. 10.1186/s12935-018-0668-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Nangia-Makker P.; Nakahara S.; Hogan V.; Raz A. Galectin-3 in apoptosis, a novel therapeutic target. J. Bioenerg. Biomembr. 2007, 39 (1), 79–84. 10.1007/s10863-006-9063-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Ahmed H.; AlSadek D. M. Galectin-3 as a Potential Target to Prevent Cancer Metastasis. Clin. Med. Insights: Oncol. 2015, 9, 113–21. 10.4137/CMO.S29462. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Elad-Sfadia G.; Haklai R.; Balan E.; Kloog Y. Galectin-3 Augments K-Ras Activation and Triggers a Ras Signal That Attenuates ERK but Not Phosphoinositide 3-Kinase Activity. J. Biol. Chem. 2004, 279 (33), 34922–34930. 10.1074/jbc.M312697200. [DOI] [PubMed] [Google Scholar]
  15. Yao Y.; Zhou L.; Liao W.; Chen H.; Du Z.; Shao C.; Wang P.; Ding K. HH1–1, a novel Galectin-3 inhibitor, exerts anti-pancreatic cancer activity by blocking Galectin-3/EGFR/AKT/FOXO3 signaling pathway. Carbohydr. Polym. 2019, 204, 111–123. 10.1016/j.carbpol.2018.10.008. [DOI] [PubMed] [Google Scholar]
  16. Farhad M.; Rolig A. S.; Redmond W. L. The role of Galectin-3 in modulating tumor growth and immunosuppression within the tumor microenvironment. Oncoimmunology 2018, 7 (6), e1434467 10.1080/2162402X.2018.1434467. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Vuong L.; Kouverianou E.; Rooney C. M.; McHugh B. J.; Howie S. E. M.; Gregory C. D.; Forbes S. J.; Henderson N. C.; Zetterberg F. R.; Nilsson U. J.; Leffler H.; Ford P.; Pedersen A.; Gravelle L.; Tantawi S.; Schambye H.; Sethi T.; MacKinnon A. C. An Orally Active Galectin-3 Antagonist Inhibits Lung Adenocarcinoma Growth and Augments Response to PD-L1 Blockade. Cancer Res. 2019, 79 (7), 1480. 10.1158/0008-5472.CAN-18-2244. [DOI] [PubMed] [Google Scholar]
  18. Campo V. L.; Marchiori M. F.; Rodrigues L. C.; Dias-Baruffi M. Synthetic glycoconjugates inhibitors of tumor-related galectin-3: an update. Glycoconjugate J. 2016, 33 (6), 853–876. 10.1007/s10719-016-9721-z. [DOI] [PubMed] [Google Scholar]
  19. Beccaria C. G.; Amezcua Vesely M. C.; Fiocca Vernengo F.; Gehrau R. C.; Ramello M. C.; Tosello Boari J.; Gorosito Serrán M.; Mucci J.; Piaggio E.; Campetella O.; Acosta Rodríguez E. V.; Montes C. L.; Gruppi A. Galectin-3 deficiency drives lupus-like disease by promoting spontaneous germinal centers formation via IFN-γ. Nat. Commun. 2018, 9 (1), 1628. 10.1038/s41467-018-04063-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Chen H. Y.; Liu F. T.; Yang R. Y. Roles of galectin-3 in immune responses. Arch. Immunol. Ther. Exp. 2005, 53 (6), 497–504. [PubMed] [Google Scholar]
  21. Besler C.; Lang D.; Urban D.; Rommel K. P.; von Roeder M.; Fengler K.; Blazek S.; Kandolf R.; Klingel K.; Thiele H.; Linke A.; Schuler G.; Adams V.; Lurz P.. Plasma and Cardiac Galectin-3 in Patients With Heart Failure Reflects Both Inflammation and Fibrosis: Implications for Its Use as a Biomarker. Circ.: Heart Failure 2017, 10 ( (3), ), 10.1161/CIRCHEARTFAILURE.116.003804 [DOI] [PubMed] [Google Scholar]
  22. Gehlken C.; Suthahar N.; Meijers W. C.; de Boer R. A. Galectin-3 in Heart Failure: An Update of the Last 3 Years. Heart Fail. Clin. 2018, 14 (1), 75–92. 10.1016/j.hfc.2017.08.009. [DOI] [PubMed] [Google Scholar]
  23. Suthahar N.; Meijers W. C.; Silljé H. H. W.; Ho J. E.; Liu F.-T.; de Boer R. A. Galectin-3 Activation and Inhibition in Heart Failure and Cardiovascular Disease: An Update. Theranostics 2018, 8 (3), 593–609. 10.7150/thno.22196. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Graham W. V.; Bonito-Oliva A.; Sakmar T. P. Update on Alzheimer’s Disease Therapy and Prevention Strategies. Annu. Rev. Med. 2017, 68, 413–430. 10.1146/annurev-med-042915-103753. [DOI] [PubMed] [Google Scholar]
  25. 2019 Alzheimer’s disease facts and figures. Alzheimer's Dementia 2019, 15 (3), 321–387. 10.1016/j.jalz.2019.01.010. [DOI] [Google Scholar]
  26. Gratuze M.; Leyns C. E. G.; Holtzman D. M. New insights into the role of TREM2 in Alzheimer’s disease. Mol. Neurodegener. 2018, 13 (1), 66. 10.1186/s13024-018-0298-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Carmona S.; Zahs K.; Wu E.; Dakin K.; Bras J.; Guerreiro R. The role of TREM2 in Alzheimer’s disease and other neurodegenerative disorders. Lancet Neurol. 2018, 17 (8), 721–730. 10.1016/S1474-4422(18)30232-1. [DOI] [PubMed] [Google Scholar]
  28. Zheng H.; Cheng B.; Li Y.; Li X.; Chen X.; Zhang Y.-W. TREM2 in Alzheimer’s Disease: Microglial Survival and Energy Metabolism. Front. Aging Neurosci. 2018, 10, 395–395. 10.3389/fnagi.2018.00395. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Yin Z.; Raj D.; Saiepour N.; Van Dam D.; Brouwer N.; Holtman I. R.; Eggen B. J. L.; Möller T.; Tamm J. A.; Abdourahman A.; Hol E. M.; Kamphuis W.; Bayer T. A.; De Deyn P. P.; Boddeke E. Immune hyperreactivity of Aβ plaque-associated microglia in Alzheimer’s disease. Neurobiol. Aging 2017, 55, 115–122. 10.1016/j.neurobiolaging.2017.03.021. [DOI] [PubMed] [Google Scholar]
  30. Lee C. Y. D.; Daggett A.; Gu X.; Jiang L. L.; Langfelder P.; Li X.; Wang N.; Zhao Y.; Park C. S.; Cooper Y.; Ferando I.; Mody I.; Coppola G.; Xu H.; Yang X. W. Elevated TREM2 Gene Dosage Reprograms Microglia Responsivity and Ameliorates Pathological Phenotypes in Alzheimer’s Disease Models. Neuron 2018, 97 (5), 1032–1048. (e5) 10.1016/j.neuron.2018.02.002. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Zhong L.; Chen X.-F.; Zhang Z.-L.; Wang Z.; Shi X.-Z.; Xu K.; Zhang Y.-W.; Xu H.; Bu G. DAP12 stabilizes the C-terminal fragment of the triggering receptor expressed on myeloid cells-2 (TREM2) and protects against LPS-induced pro-inflammatory response. J. Biol. Chem. 2015, 290, 15866–15877. 10.1074/jbc.M115.645986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Zheng H.; Liu C.-C.; Atagi Y.; Chen X.-F.; Jia L.; Yang L.; He W.; Zhang X.; Kang S. S.; Rosenberry T. L.; Fryer J. D.; Zhang Y.-W.; Xu H.; Bu G. Opposing roles of the triggering receptor expressed on myeloid cells 2 and triggering receptor expressed on myeloid cells-like transcript 2 in microglia activation. Neurobiol. Aging 2016, 42, 132–141. 10.1016/j.neurobiolaging.2016.03.004. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Song W.; Hooli B.; Mullin K.; Jin S. C.; Cella M.; Ulland T. K.; Wang Y.; Tanzi R. E.; Colonna M. Alzheimer’s disease-associated TREM2 variants exhibit either decreased or increased ligand-dependent activation. Alzheimer's Dementia 2017, 13 (4), 381–387. 10.1016/j.jalz.2016.07.004. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Zhong L.; Chen X.-F. The Emerging Roles and Therapeutic Potential of Soluble TREM2 in Alzheimer’s Disease. Front. Aging Neurosci. 2019, 11, 328–328. 10.3389/fnagi.2019.00328. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Boza-Serrano A.; Ruiz R.; Sanchez-Varo R.; García-Revilla J.; Yang Y.; Jimenez-Ferrer I.; Paulus A.; Wennström M.; Vilalta A.; Allendorf D.; Davila J. C.; Stegmayr J.; Jiménez S.; Roca-Ceballos M. A.; Navarro-Garrido V.; Swanberg M.; Hsieh C. L.; Real L. M.; Englund E.; Linse S.; Leffler H.; Nilsson U. J.; Brown G. C.; Gutierrez A.; Vitorica J.; Venero J. L.; Deierborg T. Galectin-3, a novel endogenous TREM2 ligand, detrimentally regulates inflammatory response in Alzheimer’s disease. Acta Neuropathol. 2019, 138 (2), 251–273. 10.1007/s00401-019-02013-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Tao C. C.; Cheng K. M.; Ma Y. L.; Hsu W. L.; Chen Y. C.; Fuh J. L.; Lee W. J.; Chao C. C.; Lee E. H. Y. Galectin-3 promotes Aβ oligomerization and Aβ toxicity in a mouse model of Alzheimer’s disease. Cell Death Differ. 2020, 27 (1), 192–209. 10.1038/s41418-019-0348-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Dahlqvist A.; Zetterberg F. R.; Leffler H.; Nilsson U. J. Aminopyrimidine-galactose hybrids are highly selective galectin-3 inhibitors. MedChemComm 2019, 10 (6), 913–925. 10.1039/C9MD00183B. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Peterson K.; Kumar R.; Stenström O.; Verma P.; Verma P. R.; Håkansson M.; Kahl-Knutsson B.; Zetterberg F.; Leffler H.; Akke M.; Logan D. T.; Nilsson U. J. Systematic Tuning of Fluoro-galectin-3 Interactions Provides Thiodigalactoside Derivatives with Single-Digit nM Affinity and High Selectivity. J. Med. Chem. 2018, 61 (3), 1164–1175. 10.1021/acs.jmedchem.7b01626. [DOI] [PubMed] [Google Scholar]
  39. Sörme P.; Arnoux P.; Kahl-Knutsson B.; Leffler H.; Rini J. M.; Nilsson U. J. Structural and Thermodynamic Studies on Cation-Π Interactions in Lectin-Ligand Complexes: High-Affinity Galectin-3 Inhibitors through Fine-Tuning of an Arginine-Arene Interaction. J. Am. Chem. Soc. 2005, 127 (6), 1737–1743. 10.1021/ja043475p. [DOI] [PubMed] [Google Scholar]
  40. Peterson K.; Kumar R.; Stenström O.; Verma P.; Verma P. R.; Håkansson M.; Kahl-Knutsson B.; Zetterberg F.; Leffler H.; Akke M.; Logan D. T.; Nilsson U. J. Systematic Tuning of Fluoro-galectin-3 Interactions Provides Thiodigalactoside Derivatives with Single-Digit nM Affinity and High Selectivity. J. Med. Chem. 2018, 61 (3), 1164–1175. 10.1021/acs.jmedchem.7b01626. [DOI] [PubMed] [Google Scholar]
  41. Zetterberg F. R.; Peterson K.; Johnsson R. E.; Brimert T.; Håkansson M.; Logan D. T.; Leffler H.; Nilsson U. J. Monosaccharide Derivatives with Low-Nanomolar Lectin Affinity and High Selectivity Based on Combined Fluorine-Amide, Phenyl-Arginine, Sulfur-π, and Halogen Bond Interactions. ChemMedChem 2018, 13 (2), 133–137. 10.1002/cmdc.201700744. [DOI] [PubMed] [Google Scholar]
  42. Stegmayr J.; Zetterberg F.; Carlsson M. C.; Huang X.; Sharma G.; Kahl-Knutson B.; Schambye H.; Nilsson U. J.; Oredsson S.; Leffler H. Extracellular and intracellular small-molecule galectin-3 inhibitors. Sci. Rep. 2019, 9 (1), 2186–2186. 10.1038/s41598-019-38497-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Zhang J. H.; Chung T. D.; Oldenburg K. R. A Simple Statistical Parameter for Use in Evaluation and Validation of High Throughput Screening Assays. J. Biomol. Screening 1999, 4 (2), 67–73. 10.1177/108705719900400206. [DOI] [PubMed] [Google Scholar]
  44. Cottet M.; Faklaris O.; Maurel D.; Scholler P.; Doumazane E.; Trinquet E.; Pin J. P.; Durroux T. BRET and Time-resolved FRET strategy to study GPCR oligomerization: from cell lines toward native tissues. Front. Endocrinol. (Lausanne, Switz.) 2012, 3, 92. 10.3389/fendo.2012.00092. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Sörme P.; Kahl-Knutsson B.; Huflejt M.; Nilsson U. J.; Leffler H. Fluorescence polarization as an analytical tool to evaluate galectin-ligand interactions. Anal. Biochem. 2004, 334 (1), 36–47. 10.1016/j.ab.2004.06.042. [DOI] [PubMed] [Google Scholar]
  46. Verhoest P. R.; Chapin D. S.; Corman M.; Fonseca K.; Harms J. F.; Hou X.; Marr E. S.; Menniti F. S.; Nelson F.; O’Connor R.; Pandit J.; Proulx-LaFrance C.; Schmidt A. W.; Schmidt C. J.; Suiciak J. A.; Liras S. Discovery of a Novel Class of Phosphodiesterase 10A Inhibitors and Identification of Clinical Candidate 2-[4-(1-Methyl-4-pyridin-4-yl-1H-pyrazol-3-yl)-phenoxymethyl]-quinoline (PF-2545920) for the Treatment of Schizophrenia†Coordinates of the PDE10A crystal structures have been deposited in the Protein Data Bank for compound 1 (3HQW), 2 (3HQY), 3 (3HQW) and 9 (3HR1). J. Med. Chem. 2009, 52 (16), 5188–5196. 10.1021/jm900521k. [DOI] [PubMed] [Google Scholar]
  47. Tu Z.; Fan J.; Li S.; Jones L. A.; Cui J.; Padakanti P. K.; Xu J.; Zeng D.; Shoghi K. I.; Perlmutter J. S.; Mach R. H. Radiosynthesis and in vivo evaluation of [11C]MP-10 as a PET probe for imaging PDE10A in rodent and non-human primate brain. Bioorg. Med. Chem. 2011, 19 (5), 1666–73. 10.1016/j.bmc.2011.01.032. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Ingrassia L.; Camby I.; Lefranc F.; Mathieu V.; Nshimyumukiza P.; Darro F.; Kiss R. Anti-galectin compounds as potential anti-cancer drugs. Curr. Med. Chem. 2006, 13 (29), 3513–27. 10.2174/092986706779026219. [DOI] [PubMed] [Google Scholar]
  49. Masuyer G.; Jabeen T.; Öberg C. T.; Leffler H.; Nilsson U. J.; Acharya K. R. Inhibition mechanism of human galectin-7 by a novel galactose-benzylphosphate inhibitor. FEBS J. 2012, 279 (2), 193–202. 10.1111/j.1742-4658.2011.08414.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  50. Rehman A. U.; Rahman M. U.; Lu S.; Liu H.; Li J. Y.; Arshad T.; Wadood A.; Ng H. L.; Chen H. F. Decoding allosteric communication pathways in protein lysine acetyltransferase. Int. J. Biol. Macromol. 2020, 149, 70–80. 10.1016/j.ijbiomac.2020.01.213. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

ml0c00330_si_001.pdf (300.3KB, pdf)

Articles from ACS Medicinal Chemistry Letters are provided here courtesy of American Chemical Society

RESOURCES