Small Molecule Drug Targets Research Articles

RNA-Ligand Interactions Quantified by Surface Plasmon Resonance with Reference Subtraction.

Structured RNAs bind ligands and are attractive targets for small-molecule drugs. A wide variety of analytical methods have been used to characterize RNA-ligand interactions, but our experience is that most have significant limitations in terms of material requirements and applicability to complex RNAs. Surface plasmon resonance (SPR) potentially overcomes these limitations, but we find that the standard experimental framework measures notable nonspecific electrostatic-mediated interactions, frustrating analysis of weak RNA binders. SPR measurements are typically quantified relative to a non-target reference channel. Here, we show that referencing to a channel containing a non-binding control RNA enables subtraction of nonspecific binding contributions, allowing measurements of accurate and specific binding affinities. We validated this approach for small-molecule binders of two riboswitch RNAs with affinities ranging from nanomolar to millimolar, including low-molecular-mass fragment ligands. SPR implemented with reference subtraction reliably discriminates specific from nonspecific binding, uses RNA and ligand material efficiently, and enables rapid exploration of the ligand-binding landscape for RNA targets.

Bafetinib Suppresses the Transcription of PD-L1 Through c-Myc in Lung Cancer.

Given the limitations of the existing antibody-based therapies, including immune-related adverse events, poor response rates, and intravenous route of dosing, small molecules inhibitors targeting PD-L1 are highly desirable. By cell-based screening, we found that tyrosine kinase inhibitor Bafetinib dramatically suppresses PD-L1 protein expression in a dose-dependent manner. In parallel, cell membrane PD-L1 is also reduced by Bafetinib. We confirm that Bafetinib doesn’t affect the protein half-life of PD-L1 but significantly inhibits the transcription of PD-L1. Among the transcription factors that regulate PD-L1 expression, c-Myc is downregulated by Bafetinib. Bafetinib caused PD-L1 inhibition is abolished when c-Myc is knocked-down. Further, we identified that Bafetinib reduced c-Myc expression because of transcription inhibition. By using the CT26 tumor model, we further confirm that Bafetinib suppressed PD-L1 expression in vivo. In conclusion, our study shows that Bafetinib inhibits the transcription of PD-L1 through transcription factor c-Myc, suggesting that Bafetinib might be a small molecule drug targeting PD-L1.

Using the yeast three-hybrid system for the identification of small molecule-protein interactions with the example of ethinylestradiol.

Since the first report on a yeast three-hybrid system, several approaches have successfully utilized different setups for discovering targets of small molecule drugs. Compared to broadly applied MS based target identification approaches, the yeast three-hybrid system represents a complementary method that allows for the straightforward identification of direct protein binders of selected small molecules. One major drawback of this system, however, is that the drug has to be taken up by the yeast cells in sufficient concentrations. Here, we report the establishment of a yeast three-hybrid screen in the deletion strain ABC9Δ, which is characterized by being highly permeable to small molecules. We used this system to screen for protein binding partners of ethinylestradiol, a widely used drug mainly for contraception and hormone replacement therapy. We identified procollagen-lysine 2-oxoglutarate 5-dioxygenase 2 (PLOD2 or lysyl hydroxylase, LH2) as a novel direct target and were able to confirm the interaction identified with the yeast three-hybrid system by a complementary method, affinity chromatography, to prove the validity of the hit. Furthermore, we provide evidence for an interaction between the drug and PLOD2 in vitro and in cellulo.

Targeted inhibition of PPARα ameliorates CLA-induced hypercholesterolemia via hepatic cholesterol biosynthesis reprogramming.

Disruption of lipid metabolism is largely linked to metabolic disorders, such as hypercholesterolemia (HCL) and liver steatosis. While cholesterol metabolic re-programmers can serve as targets for relevant interventions. Here we explored the dietary conjugated linoleic acids (CLA)-induced HCL in mice and the molecular regulation behind it. A high dose of CLA supplementation in the diet was used to induce HCL in mice and was found to cause a hyper-activated cholesterol biosynthesis programme in the liver, leading to cholesterol metabolism dysregulation. The effects of a small-molecule drug targeting PPARα, i.e., GW6471 were studied in vivo in mice fed diets with CLA supplementation for 28days, and in primary hepatocytes derived from HCL-mice in vitro. We demonstrate that CLA induced HCL and liver steatosis through multiple pathways. Among which was the PPARα-mediated cholesterogenesis. It was found to cooperate with SREBP2 via binding to Hmgcr and Dhcr7 (genes encoding key enzymes of the cholesterol biosynthetic pathway) and recruits the histone marks H3K27ac and H3K4me1 and cofactors. PPARα inhibition disrupts its physical association with SREBP2 by blocking cobinding of PPARα and SREBP2 to the genomic DNA response element. We showed that NR RORγ functions as an essential mediator that facilitates the interaction of PPARα and SREBP2 to modulate the cholesterol biosynthesis genes expression. Our study unravels that the small-molecule compound GW6471 exerts an attractive therapeutic effect for CLA-induced HCL, involving multiple pathways with the "PPARα-RORγ-SREBP2" being a potential complex player in this hepatic cholesterol biosynthesis programming.

Epigenetic Small-Molecule Modulators Targeting Metabolic Pathways in Cancer.

Metabolic deregulation is a key factor in cancer progression. Epigenetic changes and metabolic rewiring are intertwined in cancer. Deregulated epigenetic modifiers cause metabolic aberrations by targeting the expression of metabolic enzymes. Conversely, metabolites and cofactors affect the expression and activity of epigenetic regulators. Small molecules are promising therapeutic approaches to target the epigenetic-metabolomic crosstalk in cancer. Here, we focus on the interplay between metabolic rewiring and epigenetic landscape in the context of tumourigenesis and highlight recent advances in the use of small-molecule drug targets for therapy.

Abstract P156: Identification of previously unknown targets for approved small-molecule drugs using chemoproteomic platform IMTACTM

Abstract Small-molecule drugs exert their therapeutic effects through binding and modulating functions of their target proteins. While most approved drugs have defined target(s), a comprehensive target map is generally lacking for clinical and experimental drugs. This limits both understandings of a drug’s actions and hampers further optimization. Leveraging its proprietary chemoproteomic platform IMTACTM, BridGene Biosciences has developed an approach to generate more comprehensive target maps for approved small-molecule drugs. This approach can also be applied to drug candidates. The approach was successfully applied to a covalent drug ibrutinib and a non-covalent drug sunitinib, revealing previously unknown targets of these drugs. The drug, sunitinib or ibrutinib, was first chemically modified to generate probe compounds, which were then treated on live cells. Quantitative mass spec analysis of the resulting proteomes was performed to identify the binding targets and quantify their apparent binding affinity to the drug. The identified probe-binding proteins were then ranked based on their apparent binding affinity to determine the proteome-wide selectivity to the drug. BridGene’s IMTACTM profiling verified BTK to be the top target and two other kinases (BLK and TEC) to be prominent targets of ibrutinib in Ramos cells. Analogous IMTACTM profiling confirmed sunitinib’s binding to over a dozen of protein kinases with high to moderate affinity in Ramos cells. The kinase targets of sunitinib in Ramos cells include BLK, LYN, PTK2B, etc. Importantly, non-kinase targets included metabolic enzymes were also identified for ibrutinib and sunitinib in the IMTACTM profiling. The binding of the drugs to select new targets was verified using biochemical or binding assays. Our study demonstrates that IMTACTM profiling is a powerful approach for generating comprehensive target maps for clinical and experimental drugs, both covalent and non-covalent ones. Having target scope information will be invaluable at various stages of drug discovery and development, such as the repurposing of existing drugs, the optimization of drug candidates, as well as target identification and deconvolution for phenotypic screening hits. Citation Format: Vivian Zhang, Cindy Huang, Chao Zhang, Ping Cao. Identification of previously unknown targets for approved small-molecule drugs using chemoproteomic platform IMTACTM [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P156.

Masitinib in mild to moderate Alzheimer’s disease: Results from study AB09004

AbstractBackgroundMasitinib is a small molecule drug targeting KIT, LYN, FYN and CSF1R. Proof‐of‐concept that masitinib slowed cognitive decline in Alzheimer's disease (AD) was previously demonstrated [doi:10.1186/alzrt75; doi:10.3233/JAD‐200466]. Study AB09004 assessed oral masitinib administered as an add‐on therapy to standard care for the treatment of mild to moderate AD.MethodPhase 2B/3 study AB09004 comprised two independent, double‐blinded, placebo‐controlled, sub‐studies: masitinib at 4.5mg/kg/day versus placebo (randomized 1:1), and a titrated masitinib dose of 6.0 mg/kg/day versus matched placebo (randomized 2:1). Eligible patients that had a clinical diagnosis of AD with baseline mini‐mental state examination (MMSE) score ≥12–≤25, and had received a stable dose of cholinesterase inhibitor (donepezil, rivastigmine or galantamine) and/or memantine for ≥6 months, were treated for 24 weeks. Primary endpoint was overall change from baseline at week‐24 (analysis of covariance model) in the Alzheimer's Disease Assessment Scale‐Cognitive Subscale (ADAS‐Cog) or the Alzheimer's Disease Cooperative Study Activities of Daily Living (ADCS‐ADL) score. The study was successful if a significant improvement was reached on either ADAS‐Cog or ADCS‐ADL at a 2.5% level of statistical significance, in either sub‐study.ResultMasitinib (4.5mg/kg/day) (n=182, median (age=73 years, MMSE=19, ADCS‐ADL=55.0, ADAS‐Cog=25.5)) showed significant benefit over placebo (n=176, median (age=73 years, MMSE=19, ADCS‐ADL=53.5, ADAS‐Cog=24.8)) with a least‐squares mean difference in ADAS‐Cog from baseline (δCog) of ‐1.46 versus 0.69, respectively, and corresponding least‐squares mean difference between groups (ΔCog) of ‐2.15 (97.5%CI[‐3.48,‐0.81]);p=0.0003. All ADAS‐Cog sensitivity analyses were convergent with the primary outcome, including the conservative jump‐to‐reference approach with ΔCog of ‐1.89 (95%CI[‐3.06,‐0.72];p=0.0016). Considering ADCS‐ADL, δADL was 1.01 for masitinib (4.5mg/kg/day) versus ‐0.81 for placebo, with a ΔADL of 1.82 (97.5%CI[‐0.15,3.79]);p=0.038. Safety was consistent with the known profile for masitinib. The proportion of patients presenting at least one adverse event (AE) or severe AE was respectively, 87.0% and 26.5% for masitinib (4.5mg/kg/day, n=185) versus 77.5% and 19.3% for placebo (pooled, n=280). Efficacy results from the titrated masitinib 6.0 mg/kg/day sub‐study were inconclusive and no new safety signal was observed.ConclusionMasitinib (4.5mg/kg/day), a tyrosine kinase inhibitor targeting mast cell and microglia activity, may provide a new treatment option for mild to moderate AD.

Loss of hepatic\xa0Flcn protects against fibrosis and inflammation by activating autophagy pathways

Non-alcoholic fatty liver disease (NAFLD) is the most frequent liver disease worldwide and can progress to non-alcoholic steatohepatitis (NASH), which is characterized by triglyceride accumulation, inflammation, and fibrosis. No pharmacological agents are currently approved to treat these conditions, but it is clear now that modulation of lipid synthesis and autophagy are key biological mechanisms that could help reduce or prevent these liver diseases. The folliculin (FLCN) protein has been recently identified as a central regulatory node governing whole body energy homeostasis, and we hypothesized that FLCN regulates highly metabolic tissues like the liver. We thus generated a liver specific Flcn knockout mouse model to study its role in liver disease progression. Using the methionine- and choline-deficient diet to mimic liver fibrosis, we demonstrate that loss of Flcn reduced triglyceride accumulation, fibrosis, and inflammation in mice. In this aggressive liver disease setting, loss of Flcn led to activation of transcription factors TFEB and TFE3 to promote autophagy, promoting the degradation of intracellular lipid stores, ultimately resulting in reduced hepatocellular damage and inflammation. Hence, the activity of FLCN could be a promising target for small molecule drugs to treat liver fibrosis by specifically activating autophagy. Collectively, these results show an unexpected role for Flcn in fatty liver disease progression and highlight new potential treatment strategies.

Diethylpyrocarbonate Footprints a Membrane Protein in Micelles.

Membrane proteins play crucial roles in cell signaling and transport and, thus, are the targets of many small molecule drugs. The characterization of membrane protein structures poses challenges for the high-resolution biophysical tools because the transmembrane (TM) domain is hydrophobic, opening an opportunity for mass spectrometry (MS)-based footprinting. The hydrophobic reagent diethylpyrocarbonate (DEPC), a heavily studied footprinter for water-soluble proteins, can label up to 30% of surface residues via a straightforward protocol, streamlining the MS-based footprinting workflow. To test its applicability to membrane proteins, we footprinted vitamin K epoxide reductase (VKOR) membrane protein with DEPC. The results demonstrate that besides labeling the hydrophilic extracellular (extramembrane (EM)) domain, DEPC can also diffuse into the hydrophobic TM domain and subsequently label that region. The labeling process was facilitated by tip sonication to enhance reagent diffusion into micelles. We then analyzed the correlation between the residue modification extent and the theoretical accessible surface area percentage (%ASA); the data generally show good correlation with the residue location. Compared with conventional hydrophilic footprinters, the relatively hydrophobic DEPC can map a membrane protein's TM domain, suggesting that the reagent's hydrophobicity can be exploited to obtain structural information on the membrane-spanning region. This encouraging result should assist in the development of more efficient footprinters for membrane protein TM domain footprinting, enabled by further understanding the relationship between a reagent's hydrophobicity and its preferred labeling sites.

Whither the postdoc?

“What is happening with chemistry in America?” queries Matthew D. Hall, a biology group leader at the US National Center for Advancing Translational Sciences (NCATS) in a Twitter post July 8. “We’re losing postdocs to pharma after less than 1 year in our med chem labs. Is the job market that hot in chemistry?” The answer, in short, is yes. The combination of a healthy drug industry, heavy venture capital investment in start-ups, and new targets for small-molecule drugs is spurring a hiring spree, allowing some young PhD chemists, particularly in medicinal and computational chemistry, to skip the traditional years of postdoctoral training and go quickly to work in the pharmaceutical industry. The boom is great for chemists looking to start their careers, but it is raising questions about the role of the postdoc in the training of chemists today. Hall says he was prompted to start a conversation on

Host Directed Therapies for Tuberculous Meningitis.

A dysregulated host immune response significantly contributes to morbidity and mortality in tuberculous meningitis (TBM). Effective host directed therapies (HDTs) are critical to improve survival and clinical outcomes. Currently only one HDT, dexamethasone, is proven to improve mortality. However, there is no evidence dexamethasone reduces morbidity, how it reduces mortality is uncertain, and it has no proven benefit in HIV co-infected individuals. Further research on these aspects of its use, as well as alternative HDTs such as aspirin, thalidomide and other immunomodulatory drugs is needed. Based on new knowledge from pathogenesis studies, repurposed therapeutics which act upon small molecule drug targets may also have a role in TBM. Here we review existing literature investigating HDTs in TBM, and propose new rationale for the use of novel and repurposed drugs. We also discuss host variable responses and evidence to support a personalised approach to HDTs in TBM.

Masitinib plus gemcitabine as first-line treatment of pancreatic cancer with pain: Results from phase 3 study AB12005.

4018 Background: Masitinib (MAS) is a small molecule drug targeting mast cell and macrophage activity, innate immune cells that are critical components of the tumor microenvironment. Proof of concept that MAS in combination with gemcitabine (GEM) improved overall survival (OS) in pancreatic cancer (PC) patients (pts) with pain, was previously shown [doi 10.1093/annonc/mdv133]. The presence of pain in PC is thought to identify pts whose disease is driven in part by a pro-tumoral immune response. Methods: AB12005 was a prospective, placebo (PBO) controlled, double blind, randomized (2:1 MAS:PBO, stratified by disease stage, ECOG and geographic region) phase 3 trial, evaluating oral MAS (6.0 mg/kg/d) in combination with GEM (1000 mg/m²) against PBO plus GEM for the treatment of unresectable locally advanced PC (LAPC) and/or metastatic PC (mPC) pts with pain criteria; i.e. baseline visual analog scale of pain intensity (VAS) > 20 and/or pt treated with an opioid analgesics dose ≥1 mg/kg/d at baseline. Eligible pts were chemo-naïve with histologically or cytologically confirmed inoperable LAPC or mPC and an ECOG status ≤2. The estimated sample size was ̃330 pts to detect an OS hazard ratio (HR) of 0.68 (80% power, 2-sided α = 0.025) after 310 deaths. The study was successful if improvement in median OS (primary endpoint) relative to control reached a 2.5% level of statistical significance for either a targeted subgroup of LAPC with pain criteria, or the overall study cohort. Results: A total of 384 pts were enrolled (safety population n = 383; mITT n = 379; target subgroup n = 92). In the predefined subgroup of unresectable LAPC with pain, MAS-GEM (n = 62) showed significant benefit over PBO-GEM (n = 30) with median OS of 13.0 months (97.5% CI [11.0;18.0]) vs 11.2 months (97.5% CI [7.4;13.0]); p = 0.007. The HR was 0.46 (97.5% CI [0.2;0.9], p = 0.0047), corresponding to a significant 54% reduction in risk of death for MAS-GEM pts relative to control. Secondary analyses in the same subgroup were convergent with this primary outcome. Median PFS showed a 1.8 month between group difference in favor of MAS-GEM (p = 0.039), with a HR of 0.47 (97.5% CI [0.3;0.9], p = 0.014). The 12-month and 18-month OS rates showed a 1.3 fold and 3.4 fold improvement, respectively, in favor of MAS-GEM (53.2% and 33.9% for MAS-GEM vs 40.0% and 10% for PBO-GEM, respectively). In the overall population, comprising LAPC and mPC pts with pain, no survival benefit was observed; median OS for MAS-GEM (n = 244) was 6.9 months vs 8.0 months for PBO-GEM (n = 135); p = 0.461. The MAS-GEM combination was well tolerated with no sign of add-on toxicity. The proportion of patients presenting at least one adverse event (AE) or serious AE was respectively, 96.3% and 19.1% for MAS-GEM (n = 246) vs 99.3% and 21.3% for PBO-GEM (n = 136). Conclusions: The combination MAS (6.0 mg/kg/d) plus GEM may provide a new first line treatment option for unresectable LAPC pts with associated pain. Clinical trial information: NCT03766295.

Identification techniques of small molecule drug target proteins without chemical modification and its applications: a review

Identification of the target proteins of small molecule drugs is crucial for understanding the mechanisms of drug actions and its side effects. Conventional methods require chemical modification, which might alter the activities of the drugs. Various label-free techniques have been developed to identify drug target proteins without chemical modifications. This includes drug affinity responsive target stability (DARTS), stability of proteins from rates of oxidation (SPROX), cellular thermal shift assay (CETSA), thermal proteome profiling (TPP) and many others. Here we review the principles and applications of these label-free techniques, their advantages and limitations, as well as the most recent advances.

Tpl2 kinase regulates inflammation but not tumorigenesis in mice

Tumor progression locus 2 (Tpl2, gene name MAP3K8), a mitogen-activated protein kinase, is widely expressed in immune and non-immune cells to integrate tumor necrosis factor (TNF), toll-like receptors (TLRs), and interleukin-1 (IL1) receptor signaling to regulate inflammatory response. Given its central role in inflammatory response, Tpl2 is an attractive small molecule drug target. However, the role of Tpl2 as an oncogene or tumor suppressor gene remains controversial, and its function outside immune cells is not understood. We therefore utilized a Tpl2 kinase dead (Tpl2-KD) mouse model in an 18-month aging study to further elucidate Tpl2 effects on lifespan and chronic disease. Histopathological studies revealed the incidence and severity of spontaneous tumors and non-neoplastic lesions were comparable between wild type and Tpl2-KD mice. The only finding was that male Tpl2-KD mice had higher bodyweight and an increased incidence of liver steatosis, suggesting a sex-specific role for Tpl2 in hepatic lipid metabolism. In conclusion, loss of Tpl2 kinase activity did not lead to increased tumorigenesis over aging in mice but affected likely alterations in lipid metabolism in male animals.

De novo 3D models of SARS-CoV-2 RNA elements from consensus experimental secondary structures.

The rapid spread of COVID-19 is motivating development of antivirals targeting conserved SARS-CoV-2 molecular machinery. The SARS-CoV-2 genome includes conserved RNA elements that offer potential small-molecule drug targets, but most of their 3D structures have not been experimentally characterized. Here, we provide a compilation of chemical mapping data from our and other labs, secondary structure models, and 3D model ensembles based on Rosetta's FARFAR2 algorithm for SARS-CoV-2 RNA regions including the individual stems SL1-8 in the extended 5′ UTR; the reverse complement of the 5′ UTR SL1-4; the frameshift stimulating element (FSE); and the extended pseudoknot, hypervariable region, and s2m of the 3′ UTR. For eleven of these elements (the stems in SL1–8, reverse complement of SL1–4, FSE, s2m and 3′ UTR pseudoknot), modeling convergence supports the accuracy of predicted low energy states; subsequent cryo-EM characterization of the FSE confirms modeling accuracy. To aid efforts to discover small molecule RNA binders guided by computational models, we provide a second set of similarly prepared models for RNA riboswitches that bind small molecules. Both datasets (‘FARFAR2-SARS-CoV-2’, https://github.com/DasLab/FARFAR2-SARS-CoV-2; and ‘FARFAR2-Apo-Riboswitch’, at https://github.com/DasLab/FARFAR2-Apo-Riboswitch’) include up to 400 models for each RNA element, which may facilitate drug discovery approaches targeting dynamic ensembles of RNA molecules.

Single Molecule Investigations of Protein and Small Molecule Interactions with G-Quadruplexes and their Impact on Telomere Structure

G-quadruplex (GQ) structures form in guanine-rich segments of the genome and are particularly more prominent at telomeres and promoters. Telomeric GQ structures (GQs) have emerged as potential targets for small molecule drugs that aim to inhibit telomerase activity in cancer cells, while GQs in promoters are considered to play a role in transcription and translation level gene expression regulation. Due to their high thermal stability, GQs require activity of DNA binding proteins or helicases to be unfolded. Stabilizing small molecules are typically characterized based on their impact on thermal stability of GQs. As a physiologically more relevant approach, we determined the efficacy of several prominent small molecules based on their impact of helicase activity. We measured binding kinetics of individual small molecules and their impact on dynamics and steady state Bloom helicase (BLM) mediated GQ unfolding activities. We also studied Replication Protein A (RPA), GQ, and small molecule interactions while the GQ is maintained under tension by a looped DNA. Finally, we present FRET-PAINT measurements where we studied the accessibility of long telomeric repeats that form multiple tandem GQs and observed length dependent compaction in telomere structure.

AnnapuRNA: A scoring function for predicting RNA-small molecule binding poses

RNA is considered as an attractive target for new small molecule drugs. Designing active compounds can be facilitated by computational modeling. Most of the available tools developed for these prediction purposes, such as molecular docking or scoring functions, are parametrized for protein targets. The performance of these methods, when applied to RNA-ligand systems, is insufficient. To overcome these problems, we developed AnnapuRNA, a new knowledge-based scoring function designed to evaluate RNA-ligand complex structures, generated by any computational docking method. We also evaluated three main factors that may influence the structure prediction, i.e., the starting conformer of a ligand, the docking program, and the scoring function used. We applied the AnnapuRNA method for a post-hoc study of the recently published structures of the FMN riboswitch. Software is available at https://github.com/filipspl/AnnapuRNA.

Recognition of small molecule-RNA binding sites using RNA sequence and structure.

MotivationRNA molecules become attractive small molecule drug targets to treat disease in recent years. Computer-aided drug design can be facilitated by detecting the RNA sites that bind small molecules. However, very limited progress has been reported for the prediction of small molecule–RNA binding sites.ResultsWe developed a novel method RNAsite to predict small molecule–RNA binding sites using sequence profile- and structure-based descriptors. RNAsite was shown to be competitive with the state-of-the-art methods on the experimental structures of two independent test sets. When predicted structure models were used, RNAsite outperforms other methods by a large margin. The possibility of improving RNAsite by geometry-based binding pocket detection was investigated. The influence of RNA structure’s flexibility and the conformational changes caused by ligand binding on RNAsite were also discussed. RNAsite is anticipated to be a useful tool for the design of RNA-targeting small molecule drugs.Availability and implementation http://yanglab.nankai.edu.cn/RNAsite.Supplementary information Supplementary data are available at Bioinformatics online.

Improvement of obesity-associated disorders by a small-molecule drug targeting mitochondria of adipose tissue macrophages

Pro-inflammatory activation of adipose tissue macrophages (ATMs) is causally linked to obesity and obesity-associated disorders. A number of studies have demonstrated the crucial role of mitochondrial metabolism in macrophage activation. However, there is a lack of pharmaceutical agents to target the mitochondrial metabolism of ATMs for the treatment of obesity-related diseases. Here, we characterize a near-infrared fluorophore (IR-61) that preferentially accumulates in the mitochondria of ATMs and has a therapeutic effect on diet-induced obesity as well as obesity-associated insulin resistance and fatty liver. IR-61 inhibits the classical activation of ATMs by increasing mitochondrial complex levels and oxidative phosphorylation via the ROS/Akt/Acly pathway. Taken together, our findings indicate that specific enhancement of ATMs oxidative phosphorylation improves chronic inflammation and obesity-related disorders. IR-61 might be an anti-inflammatory agent useful for the treatment of obesity-related diseases by targeting the mitochondria of ATMs.

Strategies to gain novel Alzheimer's disease diagnostics and therapeutics using modulators of ABCA transporters.

Adenosine-triphosphate-(ATP)-binding cassette (ABC) transport proteins are ubiquitously present membrane-bound efflux pumps that distribute endo- and xenobiotics across intra- and intercellular barriers. Discovered over 40 years ago, ABC transporters have been identified as key players in various human diseases, such as multidrug-resistant cancer and atherosclerosis, but also neurodegenerative diseases, such as Alzheimer’s disease (AD). Most prominent and well-studied are ABCB1, ABCC1, and ABCG2, not only due to their contribution to the multidrug resistance (MDR) phenotype in cancer, but also due to their contribution to AD. However, our understanding of other ABC transporters is limited, and most of the 49 human ABC transporters have been largely neglected as potential targets for novel small-molecule drugs. This is especially true for the ABCA subfamily, which contains several members known to play a role in AD initiation and progression. This review provides up-to-date information on the proposed functional background and pathological role of ABCA transporters in AD. We also provide an overview of small-molecules shown to interact with ABCA transporters as well as potential in silico, in vitro, and in vivo methodologies to gain novel templates for the development of innovative ABC transporter-targeting diagnostics and therapeutics.