Biology subjects

Nada, H.

Publications and source records attributed to Nada, H..

25 records · Page 2Linked to original sources

bioRxiv2025

Discovery of CD28-Targeted Small Molecule Inhibitors of T Cell Co-stimulation Using Affinity Selection-Mass Spectrometry (AS-MS) and Ex Vivo Validation

CD28 is a key T cell co-stimulatory receptor implicated in antitumor immunity and immune-related disorders, yet no small molecule modulators of CD28 have reached clinical development. Here, we report the discovery and characterization of small molecule CD28 antagonists identified through affinity selection-mass spectrometry (AS-MS). Subsequent catalog-based structure-activity relationship (SAR) optimization led to the identification of two lead compounds, 5MS-5 and 19MS-5, which exhibit direct CD28 binding and potent inhibition of CD28-B7 interactions in cellular reporter assays. In vitro pharmacokinetic profiling demonstrated favorable solubility, metabolic stability, and permeability, alongside low off-target liabilities. Functionally, both compounds suppressed cytokine production in primary human T cells co-cultured with tumor spheroids and human epithelial tissues, validating their ability to inhibit CD28-driven immune activation in physiologically relevant models. These findings establish 5MS-5 and 19MS-5 as promising CD28 inhibitors and provide a foundation for developing orally bioavailable immunomodulators targeting T cell co-stimulation. Table of Contents artwork O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=58 SRC="FIGDIR/small/667814v1_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@2d0ab7org.highwire.dtl.DTLVardef@11a985forg.highwire.dtl.DTLVardef@109a13corg.highwire.dtl.DTLVardef@1388451_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2025

HTS-Oracle: A Retrainable AI Platform for High-Confidence Hit Identification Across Difficult-to-Drug Targets

Despite rapid advances in computational drug discovery, high-throughput screening (HTS) remains the primary method for identifying initial hits, particularly for targets with limited tractability to small molecules. Yet conventional HTS campaigns are costly and inefficient, often yielding hit rates below 2% and discarding valuable negative data. Here we present HTS-Oracle, a retrainable, deep learning-based platform that integrates transformer-derived molecular embeddings (ChemBERTa) with classical cheminformatics features in a multi-modal ensemble framework for hit prediction. We applied HTS-Oracle to the immune co-stimulatory receptor CD28, a prototypical difficult-to-drug target, and prioritized 345 candidates from a chemically diverse library of 1,120 small molecules. Experimental screening via temperature-related intensity change (TRIC) identified 29 hits (8.4% hit rate), representing an eightfold improvement over conventional methods such as surface plasmon resonance (SPR), TRIC, and affinity selection mass spectrometry (ASMS)-based HTS. By enriching true positives and filtering out non-binders upfront, HTS-Oracle streamlines the discovery pipeline and enables more focused, cost-effective screening. Two hit compounds disrupted the CD28-B7.1 interaction, with orthogonal validation provided by MST, ELISA, and molecular dynamics simulations. HTS-Oracle reduces screening burden and improves discovery efficiency, offering a powerful, scalable, and experimentally validated AI framework for accelerating hit identification across difficult-to-drug targets.

bioinformatics↗

bioRxiv2025

Discovery of an Achiral Small Molecule TREM2 Agonist with Im-proved Pharmacokinetic Profile and Validated Target Engagement

The triggering receptor expressed on myeloid cells 2 (TREM2) is a lipid-sensing immunoreceptor on microglia that has emerged as a therapeutic target for Alzheimers disease. Here, we report the discovery of C1, an achiral structural analog of VG-3927--the first small molecule TREM2 agonist to enter clinical development. C1 was synthesized via a modular and enantioselective-free route using sequential Suzuki couplings, enabling rapid scaffold diversification. Compared to VG-3927, the stereochemically simplified derivative (C1) exhibits superior microglial phagocytosis and validated target engagement. C1 induces TREM2 activation in HEK293-hTREM2/DAP12 cells, and its direct binding to TREM2 was confirmed using both microscale thermophoresis (MST) and surface plasmon resonance (SPR). Importantly, C1 also demonstrates a superior pharmacokinetic profile to VG-3927, including enhanced metabolic stability in human and mouse microsomes, favorable PAMPA permeability, and a LogD7.4 compatible with CNS penetration. Docking studies suggested a potential binding mode of C1 at the extracellular domain of TREM2, revealing key polar and hydrophobic interactions. These findings position C1 as a synthetically accessible and pharmacokinetically favorable lead for the development of TREM2-targeted therapies

pharmacology and toxicology↗

bioRxiv2025

Discovery of a First-in-Class SLIT2 Binder Disrupting the SLIT2/ROBO1 Axis via DNA-Encoded Library (DEL) Screening

The SLIT2/ROBO1 signaling axis plays a critical role in neural development, immune regulation, and tumor progression, including glioblastoma. However, small molecule inhibitors targeting this protein-protein interaction remain unexplored. Herein, we report the discovery and validation of DEL-S1, a first-in-class small molecule that binds to SLIT2 and disrupts its interaction with ROBO1. Using a DNA-encoded library (DEL) screen of 4.2 billion compounds, DEL-S1 was identified and confirmed to bind SLIT2 via temperature-related intensity change (TRIC) assay. Functional inhibition of the SLIT2/ROBO1 complex by DEL-S1 was demonstrated using a Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) assay, yielding an IC50 of 68.8 {+/-} 12.5 {micro}M. Molecular docking and molecular dynamics (MD) simulations revealed key interaction hotspots at the SLIT2 binding interface and confirmed that DEL-S1 impairs SLIT2/ROBO1 complex formation by inducing conformational rearrangements. DEL-S1 exhibited favorable ADME properties, including satisfactory plasma and microsomal stability, low cytotoxicity, and minimal hERG liability. To facilitate structure-activity relationship (SAR) exploration, we designed and implemented a modular, one-pot synthetic route leveraging cyanuric chloride reactivity, enabling rapid derivatization of the triazine scaffold of DEL-S1. This strategy yielded structurally diverse analogs, including water-soluble carboxylate derivatives with preserved SLIT2/ROBO1 inhibitory activity. Together, this work establishes a novel chemical scaffold targeting SLIT2 and introduces a flexible synthetic platform to support further optimization toward therapeutic development.

biochemistry↗

bioRxiv2025

Surface Plasmon Resonance (SPR)-Based Workflow for High-Throughput Discovery of CD28-Targeted Small Molecules

CD28 is a critical costimulatory receptor involved in T cell activation and immune regulation, making it a compelling target for immunomodulatory therapies. Despite its therapeutic relevance, small molecule CD28 inhibitors remain largely underexplored. To address this gap, we developed a high-throughput screening (HTS) workflow using surface plasmon resonance (SPR) to identify novel CD28-targeted small molecules. To our knowledge, this work represents the first SPR-based HTS platform applied to the discovery of small molecules targeting a stimulatory immune checkpoint receptor. A chemical library composed of diverse 1,056 small molecules was screened using a 384-well format. Compounds were evaluated based on level of occupancy (LO), binding response, and dissociation kinetics, resulting in 12 primary hits (1.14% hit rate). Follow-up dose-response SPR screening confirmed micromolar-range affinities for three compounds. Molecular docking and 100 ns molecular dynamics (MD) simulations of the top hit, DDS5, revealed a stable complex with CD28, maintained by hydrogen bonding and a persistent interaction with Phe93. Functional validation using a competitive ELISA confirmed that DDS5 inhibited the CD28-CD80 interaction. These results demonstrate that our SPR-based HTS platform is a robust and efficient strategy for discovering CD28-targeted small molecules. The integration of computational evaluation and orthogonal validation further underscores the potential of DDS5 as an early-stage immunomodulatory agent.

pharmacology and toxicology↗

bioRxiv2025

TREM2 Activation by First-in-Class Direct Small Molecule Agonists: DEL Screening, Optimization, Biophysical Validation, and Functional Characterization

Triggering receptor expressed on myeloid cells 2 (TREM2) is a key regulator of microglial function, and its loss-of-function variants are linked to Alzheimers disease (AD) and neurodegenerative disorders. While TREM2 activation is a promising therapeutic strategy, no small molecule agonists acting via direct TREM2 binding have been reported to date. Here, we describe the discovery of first-in-class, direct small molecule TREM2 agonists identified through DNA-encoded library (DEL) screening. The DEL hit (4a) demonstrated TREM2 binding affinity, as validated by three biophysical screening platforms (TRIC, MST, and SPR), induced Syk phosphorylation, and enhanced microglial phagocytosis. Preliminary optimization yielded 4i, which maintained TREM2 engagement with improved selectivity over TREM1 and no cytotoxicity. Molecular dynamics simulations revealed that 4a stabilizes a transient binding pocket on TREM2, suggesting a novel mechanism for receptor activation. These findings provide the first proof-of-concept for direct pharmacological TREM2 agonism, offering a foundation for developing therapeutics against AD and related disorders. Table of Contents graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=74 SRC="FIGDIR/small/655617v1_ufig1.gif" ALT="Figure 1"> View larger version (13K): org.highwire.dtl.DTLVardef@14a3d24org.highwire.dtl.DTLVardef@f423deorg.highwire.dtl.DTLVardef@5ee108org.highwire.dtl.DTLVardef@107e6df_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2025

CHI3L1-Targeted Small Molecules as Glioblastoma Therapies: Virtual Screening-Based Discovery, Biophysical Validation, Pharmacokinetic Profiling, and Evaluation in Glioblastoma Spheroids

Glioblastoma (GBM) remains the most aggressive primary brain malignancy with a 10% three- year survival rate. Chitinase-3-like protein 1 (CHI3L1) has emerged as a critical factor in the progression of GBM progression, invasion, and treatment resistance. However, small molecule inhibitors targeting CHI3L1 are largely unexplored. Microscale thermophoresis (MST) investigation of the direct binding potential of reported CHI3L1 modulators (K284, G721-0282, CHI3L1-IN-1) revealed modest to undetectable direct CHI3L1 binding affinity. Herein, pharmacophore-based virtual screening of in-house library resulted in the discovery of G28 as the most potent small molecule CHI3L1 binder reported to date. The CHI3L1 binding affinity of G28 was validated using MST and surface plasmon resonance (SPR). To evaluate the GBM-modulatory potential of G28, we conducted comprehensive pharmacokinetic and 3D spheroid studies alongside established CHI3L1 modulators. G28 demonstrated outstanding bioavailability and low toxicity, addressing key limitations faced by previous CHI3L1-targeted strategies. Notably, in 3D GBM spheroid models, G28 significantly outperformed reported CHI3L1 small molecule modulators, showing the most pronounced dose-dependent reductions in spheroid weight, migration, and viability. These findings position G28 as the most promising CHI3L1-targeted small molecule to date and a compelling candidate for GBM therapeutic development.

pharmacology and toxicology↗