A theoretical study on the activity and selectivity of IDO/TDO inhibitors.

Indoleamine 2,3-dioxygenase 1 (IDO) is a tryptophan (Trp) metabolic enzyme along the kynurenine (NFK) pathway. Under pathological conditions, IDO overexpressed by tumor cells causes depletion of tryptophan and the accumulation of metabolic products, which inhibit the local immune response and form immune escape. Therefore, the suppression of IDO activity is one of the strategies for tumor immunotherapy, and drug design for this target has been the focus of research for more than two decades. Apart from IDO, tryptophan dioxygenase (TDO) of the same family can also catalyze the same biochemical reaction in the human body, but it has different tissue distribution and substrate selectivity from IDO. Based on the principle of drug design with high potency and low cross-reactivity to specific targets, in this subject, the activity and selectivity of IDO and TDO toward small molecular inhibitors were studied from the perspective of thermodynamics and kinetics. The aim was to elucidate the structural requirements for achieving favorable biological activity and selectivity of IDO and TDO inhibitors. Specifically, the interactions of inhibitors from eight families with IDO and TDO were initially investigated through molecular docking and molecular dynamics simulations, and the thermodynamic data for binding of inhibitors were predicted by the molecular mechanics/generalized Born surface area (MM/GBSA) method. Secondly, we explored the free energy landscape of JKloops, the kinetic control element of IDO/TDO, using temperature replica exchange molecular dynamics (T-REMD) simulations and elucidated the connection between the rules of IDO/TDO conformational changes and the inhibitor selectivity mechanism. Furthermore, the binding and dissociation processes of the C1 inhibitor (NLG919) were simulated by the adaptive steering molecular dynamics (ASMD) method, which not only addressed the possible stable, metastable, and transition states for C1 inhibitor-IDO/TDO interactions, but also accurately predicted kinetic data for C1 inhibitor binding and dissociation. In conclusion, we have constructed a complete process from enzyme (IDO/TDO) conformational activation to inhibitor binding/dissociation and used the thermodynamic and kinetic data of each link as clues to verify the control mechanism of IDO/TDO on inhibitor selectivity. This is of great significance for us to understand the design principles of tumor immunotherapy drugs and to avoid drug resistance of immunotherapy drugs.

Bioorthogonal Engineered Virus-Like Nanoparticles for Efficient Gene Therapy.

Gene therapy offers potentially transformative strategies for major human diseases. However, one of the key challenges in gene therapy is developing an effective strategy that could deliver genes into the specific tissue. Here, we report a novel virus-like nanoparticle, the bioorthgonal engineered virus-like recombinant biosome (reBiosome), for efficient gene therapies of cancer and inflammatory diseases. The mutant virus-like biosome (mBiosome) is first prepared by site-specific codon mutation for displaying 4-azido-L-phenylalanine on vesicular stomatitis virus glycoprotein of eBiosome at a rational site, and the reBiosome is then prepared by clicking weak acid-responsive hydrophilic polymer onto the mBiosome via bioorthogonal chemistry. The results show that the reBiosome exhibits reduced virus-like immunogenicity, prolonged blood circulation time and enhanced gene delivery efficiency to weakly acidic foci (like tumor and arthritic tissue). Furthermore, reBiosome demonstrates robust therapeutic efficacy in breast cancer and arthritis by delivering gene editing and silencing systems, respectively. In conclusion, this study develops a universal, safe and efficient platform for gene therapies for cancer and inflammatory diseases.

A New In Situ Prepared MOF-Natural Polymer Composite Electrolyte for Solid Lithium Metal Batteries with Superior High- Rate Capability and Long-Term Cycling Stability at Ultrahigh Current Density.

Lithium metal batteries hold promise for energy storage applications but suffer from uncontrolled lithium dendrites. In this study, a new composite membrane based on modified natural polymer and ZIF-67 is designed and prepared by the in situ composite method for the first time. Among them, a modified natural polymer composed of lithium alginate (LA) and polyacrylamide (PAM) can be obtained by electrospinning. Importantly, the polar functional groups of natural polymers can interact by hydrogen bonding and MOFs can construct lithium-ion transport channels. Consequently, compared with LA-PAM electrolyte without MOF, the electrochemical stability window of ZIF-67-LA-PAM electrolyte becomes wider from 4.5 to 5.2 V, and the lithium-ion transference number (tLi+ ) enhances from 0.326 to 0.627 at 30°C. It is worth noting that the symmetric cells with ZIF-67-LA-PAM have superior stable cycling performance at 40 and 100 mA cm-2 , and a high rate at 10C and 20C for LFP cells. Besides, the cell with NCM811 high-voltage cathode can run stably for 400 cycles with an initial discharge capacity of 136.1 mAh g-1 at 0.5C. This work provides an effective method for designing and preparing MOF-natural polymer composite electrolytes and exhibits an excellent application prospect in high-energy-density lithium metal batteries.

An Oligonucleotide-Distortion-Responsive Organic Transistor for Platinum-Drug-Induced DNA-Damage Detection.

Organic transistor with DNA-damage evaluation ability can open up novel opportunities for bioelectronic devices. Even though trace amounts of drugs can cause cumulative gene damage in vivo, the extremely low occurrence proportion makes them hardly transduced into detectable electric signals. Here, an ultrasensitive DNA-damage sensor based on an oligonucleotide-distortion-responsive organic transistor (DROT) is reported by creating controllable conformation change of double-stranded DNA on the surface of organic semiconductors. In combination with interfacial charge redistribution and efficient signal amplification, the DROT provides an ultrasensitive single-site DNA-damage response with 20.5 s even upon 1 × 10-12 m cisplatin. The high generalizability of this DROT to three generations of classical platinum drugs and gene-relevant DNA damage is demonstrated. A biochip is further designed for intelligent damage analysis in complex environments, which holds the potential for high-throughput biotoxicity evaluation and drug screening in the future.

Asymmetric [3 + 3] Annulation of Copper-Allenylidenes with Pyrazolones: Synthesis of Chiral 1,4-Dihydropyrano[2,3- c]pyrazoles.

The copper-catalyzed asymmetric [3 + 3] annulation of ethynyl benzoxazinanones with pyrazolones has been achieved, providing simple access to 1,4-dihydropyrano[2,3- c]pyrazole derivatives in moderate to excellent yields with excellent enantioselectivities (up to 99% ee). Compared with previous annulation reactions of copper-allenylidenes from ethynyl benzoxazinanones, the current reaction fused the three carbon atoms of the propargyl moiety into a heterocyclic framework.