Cell Chemical Biology

Homeodomain-interacting protein kinase 4 (HIPK4) is a dual-specificity kinase that is predominantly expressed in differentiating spermatids, required for sperm development, and a promising target for nonhormonal male contraception. Genetic and functional studies have established an essential role for HIPK4 in spermiogenesis, where it acts at least in part through regulation of the F-actin-scaffolded acroplaxome during spermatid head shaping. The direct molecular targets of HIPK4 and their downstream effectors remain poorly defined, and small-molecule probes would be versatile tools for further investigating HIPK4 functions. Synthetic HIPK4 ligands could also be valuable leads for the development of nonhormonal male contraceptives. Here, we report the discovery of a cyanoquinoline-based series of HIPK4 inhibitors with nanomolar potency. Our lead compounds are selective for HIPK4, both within the HIPK family and across the broader kinome, establishing this scaffold as a useful starting point for probe and lead development. Unexpectedly, we found that a subset of these cyanoquinolines also perturbs HIPK4 proteostasis in a cell type-specific manner. In spermatids, these compounds induce the formation of detergent-insoluble HIPK4 aggregates and promote interactions between this kinase and the autophagy receptor Tax1-binding protein 1 (TAX1BP1). Together, our findings establish cyanoquinoline ligands as a new chemotype for probing HIPK4 biology and advancing male contraceptive discovery.

Aberrant WNT/{beta}-catenin signaling drives tumorigenesis and metastasis in cancer. Although enzymatic inhibitors of tankyrase (TNKS) effectively block AXIN degradation and stabilize the {beta}-catenin destruction complex (DC), they have demonstrated limited efficacy in various cancer models. Here we demonstrate that, unexpectedly, the induction of AXIN puncta represents a major barrier to achieving therapeutic efficacy. Mechanistically, catalytic inhibition of TNKS prevents TNKS turnover and drives its accumulation in the DC, wherein the scaffolding function of TNKS induces AXIN puncta formation, rigidifies the DC, and impedes {beta}-catenin turnover. Chemically induced degradation of TNKS overcomes this limitation by stabilizing AXIN without puncta formation, providing a deeper suppression of the WNT/{beta}-catenin pathway activity and the proliferation of colorectal cancer cells harboring dysfunctional APC mutations. Collectively, these findings provide an explanation for the unsatisfactory outcomes of drugging the WNT/{beta}-catenin signaling pathway by TNKS inhibitors and highlight TNKS degradation as a promising approach to treat WNT/{beta}-catenin-driven cancers.

1-deoxysphingolipids (1-deoxySLs) are atypical, cytotoxic sphingolipids (SL) formed by the serine palmitoyltransferase through the alternative use of L-Alanine over its canonical substrate L-Serine. Elevated plasma levels of 1-deoxySLs have been implicated in metabolic and neurodegenerative diseases. Due to the missing C1 hydroxyl group, 1-deoxySLs cannot be converted into complex sphingolipids nor degraded via the canonical SL catabolic pathways. However, previous reports suggested a cytochrome P450 mediated {omega}-hydroxylation of 1-deoxySLs as a potential detoxification mechanism although the exacts downstream metabolism of these lipids remained unclear. We combined genome-wide association analysis with targeted lipid analysis to identify genes involved in 1-deoxySL metabolism. Functional validation was performed in cell culture models, enzyme assays, and through quantitative high-resolution mass spectrometry using isotope labelled synthetic standards.We identified a strong association between the CYP4F2 rs2108622 variant and plasma 1-deoxySL, implicating CYP4F2 is involved in 1-deoxySL metabolism. We demonstrated that CYP4F2 catalyzes the {omega}-hydroxylation of 1-deoxysphinganine, forming a previously uncharacterized hydroxylated sphingoid base. In liver cells, this metabolite was further metabolized via three distinct pathways: one forming the N-acyl, a second involving omega acylation and third resulting in omega carboxylation. All reactions generated a new spectrum of 1-deoxysphingolipids that are based on {omega}-hydroxylated 1-deoxySA as a precursor. The metabolic steps were confirmed by structural validation using synthetically prepared external standards. Importantly, {omega}-hydroxylation significantly attenuated the acute cytotoxicity of 1-deoxySLs in liver cells, indicating that this modification is the initiating step of a multi-branched metabolic clearance pathway. This study identifies CYP4F2 as a key enzyme initiating the hepatic clearance of atypical 1-deoxySLs, mitigating their cellular toxicity and revealing multiple downstream metabolic fates. Our findings highlight a previously unrecognized clearance mechanism for atypical sphingolipids with relevance to metabolic disease.

Tumor reliance on antioxidant defenses creates a vulnerability to ferroptosis, yet strategies to therapeutically disable these systems remain limited. Here, we identify targeted degradation of the selenium uptake receptor LRP8 as an effective approach to decrease the abundance of the ferroptosis-protective enzyme glutathione peroxidase 4 (GPX4). Using bispecific cytokine receptor-targeting chimeras (KineTACs) that couple LRP8 to cytokine receptor internalization pathways, we selectively direct LRP8 to the lysosome for degradation. LRP8 degradation reduces the abundance of several selenoproteins, including GPX4, lowering the cellular threshold for lipid peroxidation and sensitizing cancer cells to ferroptosis. These findings establish receptor-mediated selenium uptake as a critical, targetable node in ferroptosis resistance and demonstrate that extracellular protein degradation can be leveraged to reprogram intracellular translational dependencies in cancer cells. More broadly, this work provides a framework for exploiting nutrient acquisition pathways to overcome therapy resistance.

To improve their chances of reproductive success, nematodes not only must arrest their development in response to adverse growth conditions but also must quickly recover if conditions improve. A polyketide synthase (PKS)-nonribosomal peptide synthetase (NRPS) hybrid assembly line that is expressed in the canal-associated neurons (CANs) of Caenorhabditis elegans promotes recovery from starvation-induced larval arrest. Here, we show that in the predatory nematode Pristionchus pacificus this assembly line produces a suite of secondary metabolites, including a family of hybrid polyketide-nonribosomal peptides known as the nemamides, the related nematides, and a family of ascarylose-modified polyketides named ascarenes. Depending on the starter unit that is loaded onto the PKS, the assembly line can produce dramatically different downstream products. Whereas the nemamides promote recovery from starvation-induced larval arrest, the ascarenes inhibit development of the dauer larval stage and promote recovery. This dichotomy suggests that the PKS-NRPS megasynthetase serves as a signaling hub in the CANs, controlling multiple developmental events. The PKS-NRPS assembly line is highly conserved across many nematode species, and identification of these chemical signals will help to elucidate the signaling pathways that control development in the worm and lead to novel anthelmintics.

-Lipoic acid (LA) is widely included in "mitochondrial cocktails" recommended to patients with primary mitochondrial disorders, yet its mechanism of action remains unclear. Here, we define the intracellular availability and functional utilization of LA in mammalian cells. We show that LA exists in two functionally distinct cellular pools: a low-abundance free pool and a protein-bound pool generated through mitochondrial fatty acid synthesis (mtFAS). Disruption of the mtFAS pathway abolishes protein lipoylation and impairs oxidative phosphorylation without altering free LA levels. Conversely, supplementation with exogenous LA markedly increases free intracellular LA without restoring protein lipoylation, mitochondrial respiration, or cell proliferation. Instead, the cellular effects of LA supplementation resemble those of the antioxidant N-acetylcysteine. These findings clarify the mechanism of action of a widely used mitochondrial supplement and identify a fundamental disconnect between cellular LA abundance and mitochondrial utilization, challenging the rationale for using LA supplementation to restore mitochondrial function.

In vitro-transcribed messenger RNA (IVT mRNA) has emerged as a versatile protein expression platform with broad clinical potential. Current optimization strategies for IVT mRNA focus on untranslated regions (UTRs), mRNA stability, and codon usage, often guided by massively parallel screening and machine learning approaches. In contrast, the Kozak sequence, a key determinant of translation initiation, is often inconsistently incorporated into synthetic 5' UTR design, and its contribution to translation efficiency remains poorly defined. Here, we systematically varied the Kozak sequence across diverse UTR contexts and performed combinatorial optimization using synthetic, established, and viral UTRs to identify design principles for enhanced translation. We show that a single-nucleotide deviation from the consensus Kozak sequence consistently enhances protein expression across UTR contexts and coding sequences. This effect is conserved across in vitro and in vivo models, highlighting the generalizability of the optimized Kozak sequence. These findings redefine the role of the Kozak sequence in synthetic mRNA design and demonstrate its substantial contribution to translation efficiency when optimized, enabling improved mRNA-based therapeutics.

The RNA demethylase FTO erases N6-methyladenosine (m6A) and cap-associated N6,2'-O-dimethyladenosine (m6Am) modifications. However, the molecular basis of its substrate selectivity and the biological effects of m6A versus m6Am demethylation in cells remain poorly understood. Here we report two engineered FTO separation-of-function mutants to selectively demethylate either m6A or m6Am modifications on RNA. While investigating the propensity of FTO active site residues to undergo self-hydroxylation, we found that mutations of FTO residue L203 resulted in impaired m6A demethylation but retained wild-type levels of m6Am demethylation, and that FTO L203A could function as a selective m6Am demethylase. Conversely, building on our recent work that identified conserved aromatic residues on FTO involved in mRNA 5' cap recognition, we found that the FTO H232A/W278A double mutant efficiently demethylates m6A modifications while exhibiting substantially impaired m6Am demethylation, making it a selective m6A demethylase. Together, these complementary FTO variants represent the first set of engineered mutations that shift FTO demethylation selectivity between m6A and m6Am substrates. These tools enable selective enzymatic removal of m6A or m6Am modifications in vitro for sequencing applications, and may facilitate understanding of FTO-mediated m6A versus m6Am demethylation in cellular and disease model systems.

Plant monoterpene indole alkaloids (MIAs) exhibit important pharmacological activities, yet understanding of their biosyntheses remains incomplete. Since protein-protein interactions (PPIs) represent a conserved regulatory mechanism in MIA-producing plants, we developed a large-scale, yeast-based screening pipeline to profile PPIs of a key enzyme, strictosidine {beta}-D-glucosidase (SGD) from Mitragyna speciosa (kratom). This screen identified six novel medium-chain dehydrogenases/reductases (MDRs) as high-confidence interaction partners of SGD. Biochemical characterization revealed that all six MsMDRs produce an MIA we named charlamine by acting directly on the reactive strictosidine aglycone intermediate, preventing its spontaneous rearrangement and establishing a functional rationale for SGD-MDR interaction. One MsMDR additionally catalyzed the reduction of vallesiachotamine, derived from the spontaneous rearrangement of strictosidine aglycone, to another previously unreported MIA, vallesiachotaminol. Parallel transcriptomics and genomics analyses uncovered a biosynthetic gene cluster containing a dihydrocorynantheine aldehyde esterase, functioning downstream of MsMDRs. Collectively, these findings demonstrate the utility of interactomics-driven plant pathway discovery. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/722234v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@1ac5843org.highwire.dtl.DTLVardef@1d6d51dorg.highwire.dtl.DTLVardef@1417446org.highwire.dtl.DTLVardef@38afb2_HPS_FORMAT_FIGEXP M_FIG C_FIG

Punicalagin, an ellagic acid polyphenol from pomegranate, has been proposed as an antagonist of protein disulfide isomerase (PDI) and endoplasmic reticulum resident protein 57 (ERp57), thiol oxidoreductases that regulate protein folding and extracellular thrombotic signaling. Here, biochemical oxidase and reductase assays on PDI show that punicalagin inhibits both activities with micromolar potency, thereby extending earlier work that described only disulfide reductase inhibition. In parallel, thiol labeling of catalytic cysteines revealed no change in the redox state, supporting a noncovalent, allosteric of inhibition. Molecular docking and molecular dynamics simulations showed that punicalagin binds stably and preferentially to defined sites on the Nterminal domains of PDI through extensive hydrogen bonding and van der Waals contacts, which is an alternative binding mode to previously reported C-terminal binding. Finally, artificial intelligence-driven network analysis identified PDI as a high-confidence target of punicalagin and related galloylated polyphenols, alongside additional signaling proteins. Together, these findings provide further mechanistic framework for punicalagin-mediated antagonism of PDI and highlight galloylated polyphenols as promising scaffolds for protein disulfide isomerase-targeted therapeutics. HighlightsO_LIPunicalagin, a galloylated polyphenol, antagonizes not only the reductase activity but also the oxidase activity of protein disulfide isomerase C_LIO_LIProtein disulfide isomerase inhibition by punicalagin is through N-terminal binding C_LIO_LIPunicalagin inhibits conformationally rather than catalytic cysteine modification C_LIO_LIArtificial intelligence network analysis reveals pathway inhibition by punicalagin C_LI

Immune checkpoint B7-H3 is an emerging target for immunotherapy. DS-7300a is an advanced B7-H3-targeting antibody-drug conjugate (ADC) warheaded with the topoisomerase I inhibitor DXd. DS-7300a has demonstrated clinical activity, but molecular biomarkers to predict its therapeutic response remain elusive. TP53 is one of the most mutated tumor suppressor genes across cancers, and effective therapies are urgently needed for TP53-deficient cancers. Using prostate cancer (PCa) as a model system, we reported that DS-7300as anti-tumor efficacy is highly dependent on functional p53 in cancer cells, and TP53 defects confer resistance to DS-7300a. Mechanistically, we found that DS-7300a and its payload, DXd, induce DNA damage and activate the ATM/ATR/CHK signaling cascade, thereby stabilizing p53 and inducing a pro-apoptotic and senescence-associated transcriptome. In contrast, TP53-deficient cells fail to detect DXd-induced DNA damage, maintain a high proliferation rate, and exhibit low levels of apoptosis and senescence, thereby conferring resistance to DS-7300a. Ferroptosis is an iron-dependent form of regulated cell death triggered by lipid peroxidation, which is mechanistically and morphologically distinct from apoptosis. Interestingly, DS-7300a treatment elevates lipid peroxidation in TP53-deficient cancer cells and upregulates glutathione peroxidase 4 (GPX4), an antioxidant enzyme that mitigates lipid peroxidation. Using isogeneic xenograft models and a newly developed humanized B7-H3 PCa model, we demonstrated that inducing ferroptosis by pharmacological inhibition of GPX4 enhances DS-7300as efficacy in TP53-deficient tumors. Our studies demonstrate that TP53 status dictates anti-tumor responses to DS-7300a, and ferroptosis induction represents a promising therapeutic approach to overcome resistance to DS-7300a in malignancies harboring TP53 defects.

Tuberculosis (TB), particularly drug-resistant tuberculosis (DR-TB), remains a critical global challenge and underscores the urgent need for novel drugs and innovative combination regimens with distinct mechanisms of action. Here, we characterize an all-oral three-drug regimen comprising TBI-166, bedaquiline(BDQ), and pyrazinamide(PZA), which displays strong synergistic antimicrobial activity in vitro against both replicating and non-replicating Mycobacterium tuberculosis (MTB) and has previously shown superior bactericidal and sterilizing efficacy to standard HRZ and BPaL regimens in murine TB models(1). Time-kill studies demonstrate that the triple regimen outperforms dual-drug combinations, accelerating bacterial clearance across multiple physiological states. Mechanistic investigations revealed that the TBI-166-BDQ-PZA combination induces a comprehensive collapse of energy and redox homeostasis, marked by profound ATP depletion, robust accumulation of reactive oxygen species (ROS), and marked disruption of the intracellular NAD(H) pool. TBI-166, a novel riminophenazine analogue of clofazimine (CFZ) currently in phase II clinical trials, emerged as a key contributor to this metabolic stress. Metabolomic profiling and {superscript 1}3C-based flux analysis show that TBI-166 slows glycolysis and the tricarboxylic acid (TCA) cycle while enhancing flux through the pentose phosphate and nicotinate pathways, thereby lowering the NADH/NAD ratio and diminishing MTB metabolic flexibility under environmental stress. In parallel, TBI-166 downregulates the dormancy regulator DosR and its regulon, further compromising adaptation to non-replicating states. Multi-omics analyses, together with biochemical and biophysical assays, identify the pyruvate dehydrogenase complex (PDHc) components DlaT and LpdC as direct molecular targets of TBI-166, with drug binding leading to potent inhibition of their enzymatic activities. Collectively, these findings define the mechanism of action of TBI-166 and provide a molecular rationale for its inclusion in potent, all-oral, short-course regimens. More broadly, they highlight the therapeutic potential of metabolically targeted combinations that destabilize energy metabolism, redox balance, and metabolic adaptability to improve DR-TB treatment outcomes.

G protein-coupled receptors (GPCRs) constitute the largest and most diverse class of membrane receptors encoded in the human genome. They detect a wide range of chemical and physical stimuli and transduce these signals into intracellular responses through highly regulated pathways. Reflecting their central role in physiology, GPCRs are among the most prominent targets in drug discovery. However, identifying ligands that recognize GPCRs in their native conformational and membrane context remains a significant challenge. Here, we report an expanded aptamer discovery platform based on ligand-guided selection (LIGS) to isolate aptamers against GPCRs in their native cellular state. Using the {beta}2-adrenergic receptor ({beta}2AR) as a model system and employing agonists and antagonists as competing ligands, we identified three aptamers with high specificity for {beta}2AR. These aptamers exhibit selective binding to cell-surface {beta}2AR, showing higher apparent affinity towards cell-membrane bound {beta}2AR than toward the purified receptor, which is consistent with recognition of native receptor context. Beyond target recognition, we show that the selected aptamers induce rapid internalization, indicating functional engagement. Together, these findings establish ligand-guided selection as a generalizable strategy for the discovery of conformationally sensitive aptamers targeting GPCRs in their native membrane environments. SignificanceThe ability to discover ligands for receptors that undergo dynamic conformational changes is essential for advancing targeted therapeutics. G protein-coupled receptors (GPCRs), among the most sought-after drug targets, exist in transient and heterogeneous conformational states that are difficult to replicate in purified or artificial systems. Here, we introduce a ligand discovery platform that leverages native receptor interactions with agonists and antagonists to enable the selection of nucleic acid ligands (aptamers) directly against GPCRs in their cellular context, eliminating the need for purified receptors. The resulting aptamers exhibit selective binding to membrane-bound receptors and display intracellular functionality, highlighting a broadly applicable strategy for discovering ligands that recognize and modulate GPCRs in their native environments.

Isoflavone hydroxylases (IFHs, CYP81E) convert isoflavone aglycones into their respective hydroxylated intermediates, which direct legume isoflavones into specialized defense pathways. In soybean, their functions have been studied mostly in the context of the daidzein-derived glyceollin biosynthesis. Here we combine metabolomics-guided feature mining, phylogenetic analysis, heterologous enzymology, structural elucidation, and in planta metabolite validation to determine the functional landscape of the soybean IFH family. Analysis of a soybean isoflavonoid-enriched metabolomic dataset revealed unidentified hydroxyisoflavone features that co-accumulated with glyceollins, indicating branch chemistry that is not well-recognized. The systematic characterization of the repertoire of soybean CYP81E has demonstrated that 9 out of 11 GmIFHs are catalytically active and collectively span both 2'- and 3'- hydroxylation of the major soybean isoflavone aglycones. Among them, GmIFH9A showed broad substrate scope and regioselectivity, yielding canonical and previously unknown hydroxylated isoflavone products. NMR and LC-MS/MS were used to identify and validate the hydroxylated isoflavone products as 2'-hydroxyglycitein and 2'-hydroxyformononetin, whose presence was also confirmed in soybean roots, thus confirming two of the hidden soybean isoflavonoid network metabolites. Kinetic studies also indicated that, although the majority of GmIFHs prefer daidzein and genistein as substrates, a few isoforms are active towards methoxylated isoflavones as well, indicating functional divergence in this expanded family. Our findings collectively redefine soybean IFHs as a multi-functional enzyme module that expands the hydroxyisoflavone chemical space and reveals new biosynthetic entry points beyond canonical glyceollin pathway.

{beta}4-galactosylation is a critical quality attribute of therapeutic monoclonal antibodies (mAbs), enhancing complement-dependent cytotoxicity, antibody-dependent cytotoxicity, and antibody-dependent cellular phagocytosis. Despite its therapeutic importance, galactosylation remains the most variable glycosylation motif due to its sensitivity to cell culture conditions. Here, we describe a dual genetic engineering strategy applied to two mAb-producing CHO cell lines, DP12 and VRC01, to simultaneously overcome the cellular machinery and metabolic bottlenecks that limit {beta}4-galactosylation. The first engineering event knocks out COSMC, the chaperone required for core 1 {beta}-1,3-galactosyltransferase 1 activity, to redirect UDP-Gal consumption from O-linked {beta}3-galactosylation towards mAb Fc N-linked {beta}4-galactosylation. The second event overexpresses {beta}-1,4-galactosyltransferase 1 ({beta}4GalT1) to augment cellular galactosylation machinery. Each modification was characterised individually (COSMC- and GalT+) and in combination (C-/GT+) across both cell lines in batch and fed batch cultures. The combined C-/GT+ strategy consistently achieved greater than 90% mAb Fc {beta}4-galactosylation, irrespective of host cell line or culture mode. Metabolic characterisation confirmed that both engineering events alleviate their respective bottlenecks: COSMC knockout redirects UDP-Gal flux and {beta}4GalT1 overexpression increases N-galactosylation capacity. The C-/GT+ strategy also reduced production of Man5 glycans, which accelerate serum clearance and pose immunogenicity risks. Metabolic profiling suggests that the COSMC knockout attenuates UTP consumption and contributes to reduced Man5 production. C-/GT+ glycoengineering had no negative impact on mAb titre. Our results establish the C-/GT+ dual glycoengineering strategy as a robust approach for consistently achieving high mAb galactosylation across diverse cell culture conditions, with the additional benefit of reduced Man5 glycans. HighlightsO_LIDual COSMC KO and {beta}4GalT1 overexpression achieves >90% mAb Fc galactosylation. C_LIO_LICOSMC KO redirects UDP-Gal from O-glycans to mAb Fc without impacting cell growth. C_LIO_LIDual glycoengineering reduces production of undesired Man5 glycans. C_LI

Structured RNAs cause human diseases but remain challenging to target selectively with small molecules. Here, we report a chemoinformatics-guided discovery framework that integrates fingerprint-based molecular design, experimental validation, and mechanistic profiling to identify small molecules that bind highly structured, disease-associated RNAs. Using an RNA-binder fingerprint derived from known ligands, a Tversky similarity screen of >8 million compounds yielded a 150-member library enriched in chemical space for RNA-active scaffolds. Target engagement and cell-based assays identified multiple selective ligands for the pathogenic expanded triplet repeat, r(CUG)exp, that causes myotonic dystrophy type 1 (DM1) by binding and sequestering the RNA-binding protein muscleblind-like 1 (MBNL1). Biophysical and single-molecule analyses revealed that the small molecules bind the 1x1 nucleotide U/U internal loops formed when r(CUG)exp folds, partially block MBNL1 binding, and modulate RNA folding equilibria. Two optimized scaffolds rescued MBNL1-dependent splicing in patient-derived myotubes with micromolar potency and minimal cytotoxicity. This study establishes a generalizable, data-driven platform for discovering drug-like RNA-binding lead small molecules and demonstrates its application to the toxic repeat expansion RNA underlying DM1. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=97 SRC="FIGDIR/small/723748v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1a87b41org.highwire.dtl.DTLVardef@340a14org.highwire.dtl.DTLVardef@81b583org.highwire.dtl.DTLVardef@1b3ba14_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

Drug-metabolizing enzymes determine therapeutic exposure, efficacy and toxicity, but defining their isoform-specific functions in vivo remains challenging. Cytochrome P450 enzymes (P450s) are central to drug metabolism and pharmacokinetics (DMPK) and mediate the phase I metabolism of [~]75% of all marketed drugs. However, conventional knockout models can induce develop-mental and compensatory adaptations, and selective inhibitors are unavailable for many P450 isoforms. Here, we report the use of an inducible chemical-genetic platform for acute and specific degradation of the endogenous P450 enzyme Cyp1a2 in mice. Using CRISPR-Cas9-mediated knock-in editing, we introduced an FKBP12F36V degron into the endogenous Cyp1a2 locus to generate Cyp1a2dTAG mice. Treatment with the dTAG degrader dTAG-13 recruited an E3 ubiquitin ligase to CYP1A2dTAG, resulting in rapid and reversible proteasomal depletion of CYP1A2dTAG in vivo. Temporally controlled CYP1A2dTAG loss altered caffeine pharmacokinetics as expected, validating this model as a functional tool for DMPK studies. By enabling reversible suppression of drug-metabolizing enzymes without permanent deletion or chronic inhibitor exposure, this work establishes targeted protein degradation as a broadly adaptable strategy for studying drug metabolism in vivo and provides a foundation for extending inducible DMPK control to other P450s, conjugating enzymes and transporters.

Kinases have proven to be one of the most fertile target classes for new drug approvals. However, classical reversible inhibitors may not be capable of the levels of specificity or target modulation required across a broad spectrum of disease areas. Approaches that chemically modify kinase inhibitors in solvent exposed regions are unveiling a swathe of mechanisms to address kinase function in new ways. For example, by either covalently recruiting nucleophilic residues outside of the ATP-binding pocket to inhibit, or by recruiting secondary effector proteins to degrade. Here, we systematically assessed the impact of minimal electrophilic modifications to ATP-site binding scaffolds, leading us to identify molecules that can control the activity and abundance of the master autophagy regulator, Unc-51-like autophagy activating kinase 1 (ULK1).

Malaria remains one of the major threats to human health. Breakthrough drugs with high potency and low resistance risk are needed to combat the ever-increasing resistance to currently deployed antimalarials. Here, we explore a series of 4-amino-quinazoline-based sulfonamides, with drug-like physicochemical parameters and a synthetically accessible scaffold. Exemplars exhibit nanomolar potency against blood stage Plasmodium cultures, with up to 300-fold selectivity compared with a mammalian cell line. The compounds are also active against transmissible stages of P. falciparum and are refractory to resistance development. Targeted mass spectrometry reveals that the compounds act as reaction hijacking inhibitors targeting P. falciparum aminoacyl tRNA synthetases (aaRSs). Subtle changes to the chemical structure switch the main target from cytoplasmic tRNA threonine synthetase (PfThrRS) to cytoplasmic asparagine synthetase (PfAsnRS), a change that is associated with increased potency and selectivity. The target preference was confirmed by selective knock-down of different P. falciparum aaRSs and by tolerance selection in a mutator line. Consistent with aaRS targets, exemplar compounds activate the amino acid starvation response. Recombinant enzyme inhibition and thermal stabilisation assays confirm the susceptibility of PfAsnRS to reaction hijacking and show that human AsnRS is less susceptible. A molecular model of Asn-tRNA-bound PfAsnRS reveals that a potent hijacker adopts a pose similar to adenosine 5-monophosphate (AMP). An AlphaFold model of the native PfAsnRS dimer helps explain the tolerance-conferring effect of a mutation at the dimer interface.

Despite the therapeutic promise of uric acid-metabolizing microbes for hyperuricemia, their application is hindered by the scarcity of highly efficacious strains. To identify uric acid-metabolizing microbes, we enriched gut microbiota from cynomolgus monkeys under uric acid-supplemented conditions. This selection increased the abundance of Prevotellaceae_UCG-001 and norank_f_Prevotellaceae, implicating Prevotella species as key uric acid degraders. In vitro validation confirmed efficient uric acid consumption by two new Prevotella isolates and the reference strain Prevotella copri DSM 18205 (P. copri). Oral administration of P. copri in hyperuricemic mice reduced uric acid levels in serum and kidney tissues and alleviated renal fibrosis by suppressing the TGF-{beta}/Smad pathway and downstream fibrogenic genes. Moreover, P. copri administration restored the depleted population of Faecalibaculum, and further assays demonstrated that Faecalibaculum rodentium directly metabolizes uric acid. Collectively, P. copri alleviates hyperuricemia via a dual mechanism: direct uric acid catabolism and enrichment of commensal uric acid-consuming bacteria. These findings establish P. copri as a promising live biotherapeutic agent for hyperuricemia and highlight microbial collaboration as a therapeutic strategy for metabolic diseases.