Bioconjugate Chemistry最新文献

Protein cages provideuseful scaffolds for nanoscale engineeringbecause of their highly ordered structures and in vivo self-assembly. These scaffolds are amenable to late-stage conjugation,enabling an expansion in functionality. However, many conjugationtechniques either lack site selectivity, require unnatural amino acidincorporation, or have bulky recognition motifs to facilitate ligationreactions. Here, an asparaginyl endopeptidase (AEP) enzyme with ligaseactivity is employed for the highly efficient functionalization ofvirus-like particles (VLPs) from Enterobacteria phage P22. The capacityof this enzyme to conjugate peptides and proteins onto assembled P22VLPs under mild reaction conditions via a minimal extension to theP22 coat protein C-terminus is demonstrated. We extend the reactionefficiency to facilitate a one-pot dual-functionalization reaction,in which two therapeutically relevant receptor-targeting domains areconjugated to P22 VLPs in a single step. Finally, we demonstrate thepotential for AEP-mediated bioconjugation to bestow P22 VLPs withreceptor-binding functionality in vitro. This workdemonstrates the efficacy of AEP ligases as bioconjugation tools forthe site-selective functionalization of large molecular assembliessuch as VLPs.

When trihydroxypiperidine (PIP) or DAB-1 pyrrolidine(PYR) iminosugarsare multimerized on the prism[5]arene scaffold, they generate highlyefficient multivalent inhibitors of GCase. Binding trihydroxypiperidineto the rims of prism[5]arene (PrS[5]^PIP) results in a multivalent derivative thatis more effective than others reported in the literature with thesame bioactive unit. This efficacy is attributed to the role of prism[5]arene,whose barrel-like shape exposes an external π-surface that enablesvan der Waals contacts and other secondary interactions with the enzyme,thereby enhancing affinity for GCase through dimer stabilization.The high efficiency of PrS[5]^PIP is supported by in silico calculationsthat showed how the crowding of the bioactive units on the rims ofthe macrocycle promotes a rearrangement allowing the active site toaccommodate two trihydroxypiperidine units, which engage in hydrogenbonding with the catalytically active Glu residues. Due to their inhibitorypotency, these prismarene derivatives have been tested as pharmacologicalchaperones in intact cell lines from Gaucher patients carrying differentmutations. The results indicated that the PrS[5]^PIP is more effective towardthe N370S mutation, while the DAB-1 pyrrolidine iminosugar PrS[5]^PYR unexpectedly enhancesL444P mutant GCase activity. This suggests that the type of iminosugarlinked to the prismarene scaffold influences GCase activity rescuein a mutation-dependent manner and opens the way for the future developmentof increasingly efficient pharmacological chaperones.

Proteins and nucleic acids represent nature’smost versatilebiomolecules. By leveraging the functionality of proteins and theprogrammability of nucleic acids, along with the exquisite recognitionproperties of both, protein-nucleic acid conjugates can unlock hybridsystems that outperform either component alone. In this Viewpoint,we discuss emerging applications of protein–nucleic acid conjugatesin biorecognition and therapeutics. As detection tools, these structurescan identify molecules in complex media and single living cells withhigh selectivity or amplify signals to create assays with ultralowlimits of detection. For therapeutics, they can be engineered to regulategenes in a tissue-selective manner, act as immunotherapies, or formthe basis of new biomaterials with unique in vitro and in vivo properties. We end by focusing on theoutstanding challenges that remain before the full potential of thesestructures is realized in revolutionizing diagnostics and medicine.

LipidA, the hydrophobic anchor of lipopolysaccharide in the outermembrane of Gram-negative bacteria, serves as its principal immunostimulatorycenter. Variations in acyl chain numbers and lengths, phosphorylationstatus, and substituent groups directly influence the immunologicalresponses elicited by this molecule. A representative example is monophosphoryllipid A (MPLA), a dephosphorylated derivative of lipid A. This 1-O-dephosphorylated variant largely preserves the immunostimulatorystrength of lipid A while showing substantially lower toxicity─aproperty that has made it clinically successful as a vaccine adjuvant.The synthesis of lipid A and its derivatives has attracted extensiveattention from synthetic chemists. Understanding the structure–activityrelationships (SARs) of these molecules has therefore remained a centralgoal in the field. However, systematic SAR work and the creation ofstructurally defined variants depend on reliable synthetic access,which continues to pose significant difficulties. In particular, thestereoselective assembly of the diglucosamine core and the preciseinstallation of diverse acyl and phosphate groups present substantialsynthetic hurdles. While numerous synthetic routes have emerged forlipid A and its derivatives over the past few decades, a general andeffective method for assembling the diglucosamine core remains tobe established. This review systematically summarizes these syntheticadvances, with a particular emphasis on rational design and structuralconsiderations. We highlight strategies and concepts developed toaddress key chemoselective, stereoselective, and enantioselectivechallenges during assembly of the characteristic bisphosphorylatedβ-(1→6)-linked diglucosamine backbone. Finally, we outlinethe fundamental relationships between unique molecular conformationsof lipid A and their resulting biological activities. This reviewprovides theoretical guidance for designing rational synthetic routesof novel lipid A and its derivatives MPLA, selectively regulatingstereoselectivity issues, and the development of targeted, more effectiveimmunotherapies and vaccine adjuvants.

Nectin-4 is a validatedtarget for theranostic approachestowardurothelial carcinoma, and radiolabeled ligands for PET and SPECT imagingare gaining increasing interest for noninvasive quantification ofNectin-4 prior to a targeted therapy. The goal of this study was todevelop bicyclic peptides that allow radiolabeling with three differentradionuclides (⁶¹Cu, ⁶⁴Cu, and ⁶⁸Ga) and to evaluate their suitability for high-contrast PET imagingin urothelial carcinoma (UC) and triple-negative breast cancer (TNBC).For this purpose, NECT-330, NECT-334, and NECT-346 were designed based on our previously developed ligand NECT-224 but harbor additional linker units between the bicyclicscaffold and the radiometal chelator. Binding kinetics to recombinantNectin-4 and related isoforms were assessed by surface plasmon resonance(SPR) interaction analysis. Nectin-4-specific cell binding of theradiolabeled probes was determined using UC and TNBC cell lines, andPET/CT imaging was performed in respective tumor xenograft models.All novel ligands showed potent and selective binding to Nectin-4,with improved k_off values compared to NECT-224. In small-animal PET/CT imaging studies, the mostfavorable properties were observed for [⁶⁴Cu]Cu-NECT-334 (tumor-to-muscle of 20.8 and tumor-to-heartof 11.2) and [⁶⁴Cu]Cu-NECT-346 (tumor-to-muscle of 15.5 and tumor-to-heart of 8.7) 1–2 hpostinjection using a HT-1376 tumor model. Although the novel radioligandsprovided superior imaging properties to the previously developed radioligand[⁶⁴Cu]Cu-NECT-224, a first-in-humanapplication of the latter radioligand was initiated to assess thegeneral suitability of PET/CT imaging in humans with a ⁶⁴Cu-labeled bicyclic peptide directed to Nectin-4. Prospectively,the improved tumor-to-background contrasts achieved with the novelradioligands might further improve diagnostic accuracy and facilitateeffective theranostic options in Nectin-4-expressing malignancies.

Peptideand peptoid are two types of peptidomimetics can be usedas drugs for diseases. One of the main hallmarks in Alzheimer’sDisease (AD) is Aβ aggregation. Due to the natural affinitybetween peptide and Aβ proteins, peptide therapeutics are foundout to be suitable for the disease, as they are almost nontoxic, possessgood biocompatibility and are structurally changeable. This reviewmainly focuses on peptide and peptoid as inhibitors targeting Aβprotein, elaborating on their design strategies and some of theirinhibitory effects, providing diverse potential compounds for thetreatment of AD. The involved peptide inhibitors are classified intothree major categories based on their structural features: inhibitorsbased on the natural Aβ sequence, inhibitors based on non-naturalAβ sequences, and inhibitors conjugated with small moleculecompounds. To facilitate understanding of the development processof each type of inhibitor, we have expounded on each major categoryin terms of chronological order, specialty and importance. It alsosummarized the challenges and design strategies faced by peptide inhibitorsin targeting Aβ aggregation. This review provides a valuableresource for researchers in the field of synthetic peptide and theirbiomedical applications, offering structural insights into the designof new peptide for better diagnosis and therapeutic applications.

Hydroxypyridyl-substituted 1,2,4,5-tetrazines have recentlybeendeveloped as advanced scissors for bioorthogonal click-to-releasechemistry. In contrast to the otherwise characteristic pink colorof 1,2,4,5-tetrazines, these compounds were observed to give yellowsolutions in methanol and buffered aqueous media. This study showsthat the solvatochromism of hydroxypyridyl-tetrazines has its originin varying protonation states of the phenolic OH group and revealsthe impact of deprotonation on bioorthogonal click reactivity. Wedemonstrate that the rate of the Diels–Alder cycloadditionis significantly affected by the pH of the aqueous solution, therebyproviding critical insights for the development of molecular toolsfor bioorthogonal bond cleavage.

The recent development of Volumetric Imaging via PhotochemicalSectioning (VIPS) has enabled nanoscale imaging of whole-mount tissuesamples of virtually any size by embedding intact tissue in a photocleavable,superabsorbent hydrogel. However, the efficacy of sample embedding,imaging, and photochemical sectioning is fundamentally governed bythe mechanical stiffness, structural stability, and photodegradation performance of the photocleavable hydrogel (PC-gel) polymer network.To elucidate the effect of the photosensitive cross-linker designon these critical properties, we synthesized a set of photocleavablecross-linkers (PCs) with varying polyethylene glycol (PEG) backbonelengths and prepared the corresponding PC-gels under a fixed monomerformulation and polymerization condition. We quantified and comparedthe viscoelastic properties of the formed PC-gels in their swollenstates, and found that the cross-linker length markedly reshaped thePC-gel mechanics. In addition, we evaluated the light-triggered degradationof the PC-gels using both wide-field and spatially controlled illumination.We found that PC-1000, PC-1500, and PC-2000 gels remained comparablyphotodegradable, all enabling on-demand, spatially confined decross-linkingunder such illumination. These results provide practical guidelinesfor modulating the cross-linker architecture of PC-gel polymer networksto achieve optimal physicochemical properties for whole-mount tissueimaging using VIPS.

Radiotherapy (RT), a cornerstone of modern oncology,is often hinderedby the hypoxic tumor microenvironment (TME), inherent radioresistance,and collateral damage to surrounding healthy tissues. To circumventthese limitations, we developed a biomimetic, interfacially engineerednanoplatform (CMHHND) designed for precision synergistic therapy.The nanoplatform features hafnium-doped hollow Prussian blue (HHPB)nanocatalysts as a functional core, which are loaded with nuclear-targeteddoxorubicin and encapsulated within a homologous cancer cell membrane(CM) shell. This macromolecular camouflage grants the system exceptionalcolloidal stability and superior homotypic targeting capabilitiesthrough interfacial molecular recognition. Mechanistically, CMHHNDfunctions as a multimodal agent: it acts as a photothermal agent,a dual-enzyme mimic with catalase (CAT)- and peroxidase (POD)-likeactivities to modulate the TME, and a radiosensitizer leveraging thehigh atomic number (Z) of Hf to enhance X-ray deposition. Systematic in vivo experiments confirmed that CMHHND-mediated synergistictherapy (RT/PTT/Chemo) effectively eradicated 4T1 tumors with no apparentsystemic toxicity. Our findings highlight that integrating biomimeticinterfacial engineering with multifunctional nanocatalysts providesa potent strategy to reverse hypoxia-associated radioresistance, offeringa robust paradigm for the design of advanced colloidal nanomedicinesin precision cancer therapy.

Ovarian cancer remains a lethal malignancy due to chemoresistanceand toxicity, which limits the dose of chemotherapy that can be used,necessitating the development of more targeted therapies such as antibody-drugconjugates (ADCs). However, conventional ADCs suffer from heterogeneity.This study aimed to develop a stable, homogeneous ADC by utilizinga bifunctional dibromomaleimide (DBM) linker to cross-link antibodycysteine residues via disulfide-bridging. A DBM linker was synthesizedfrom 3,4-dibromofuran-2,5-dione and bound to the cytotoxic agent triptolide.This triptolide payload was then conjugated to trastuzumab via site-specificdisulfide rebridging to yield a homogeneous trastuzumab-triptolideconjugate to target human epithelial growth factor receptor 2 (HER2)on ovarian cancer cells. The study evaluated the ADC’s efficacyagainst SKOV-3 (high HER2 expression) and OVCAR-8 (low HER2 expression)cell lines. The results showed that the ADC was slightly more potentin SKOV-3 cells, yielding lower IC₅₀ values compared toOVCAR-8. Mechanistic studies of the ADC via flow cytometry revealedthat the ADC induced significant apoptosis and cell cycle arrest,characterized by a concentration-dependent increase in Caspase-3/7expression and distinct alterations in cell population distribution.Furthermore, ADC treatment led to a concentration-dependent decreasein HER2 levels in SKOV-3 cells, confirming successful targeting. Thestudy demonstrates that converting conventional maleimides into bifunctionalDBM linkers allows the production of a homogeneous ADC via disulfide-bridging.This approach offers a promising strategy for developing potent anticancertherapeutics with improved selectivity for HER2-overexpressing ovariancancers.