Degradable living plastics programmed by engineered spores.

Plastics are widely used materials that pose an ecological challenge because their wastes are difficult to degrade. Embedding enzymes and biomachinery within polymers could enable the biodegradation and disposal of plastics. However, enzymes rarely function under conditions suitable for polymer processing. Here, we report degradable living plastics by harnessing synthetic biology and polymer engineering. We engineered Bacillus subtilis spores harboring the gene circuit for the xylose-inducible secretory expression of Burkholderia cepacia lipase (BC-lipase). The spores that were resilient to stresses during material processing were mixed with poly(caprolactone) to produce living plastics in various formats. Spore incorporation did not compromise the physical properties of the materials. Spore recovery was triggered by eroding the plastic surface, after which the BC-lipase released by the germinated cells caused near-complete depolymerization of the polymer matrix. This study showcases a method for fabricating green plastics that can function when the spores are latent and decay when the spores are activated and sheds light on the development of materials for sustainability.

Lysosome Targeting Chimaeras for Glut1-Facilitated Targeted Protein Degradation.

Targeted protein degradation technology holds great potential in biomedicine, particularly in treating tumors and other protein-related diseases. Research on intracellular protein degradation using molecular glues and PROTAC technology is leading, while research on the degradation of membrane proteins and extracellular proteins through the lysosomal pathway is still in the preclinical stage. The scarcity of useful targets is an immense limitation to technological advancement, making it essential to explore novel, potentially effective approaches for targeted lysosomal degradation. Here, we employed the glucose transporter Glut1 as an innovative lysosome-targeting receptor and devised the Glut1-Facilitated Lysosomal Degradation (GFLD) strategy. We synthesized potential Glut1 ligands via reversible addition-fragmentation chain transfer (RAFT) polymerization and acquired antibody-glycooligomer conjugates through bioorthogonal reactions as lysosome-targeting protein degradation molecules, utilized in the management of PD-L1 high-expressing triple-negative breast cancer. The glucose transporter Glut1 as a lysosome-targeting receptor exhibits potential for the advancement of a broader array of medications in the future.

CRISPR/Cas9-mediated efficient white genome editing in the black soldier fly Hermetia illucens.

The CRISPR/Cas9 system is the most straightforward genome-editing technology to date, enabling genetic engineering in many insects, including the black soldier fly, Hermetia illucens. The white gene plays a significant role in the multifarious life activities of insects, especially the pigmentation of the eyes. In this study, the white gene of H. illucens (Hiwhite) was cloned, identified, and bioinformatically analysed for the first time. Using quantitative real-time polymerase chain reaction (qPCR), we found that the white gene was expressed in the whole body of the adult flies, particularly in Malpighian tubules and compound eyes. Furthermore, we utilised CRISPR/Cas9-mediated genome-editing technology to successfully generate heritable Hiwhite mutants using two single guide RNAs. During Hiwhite genome editing, we determined the timing, method, and needle-pulling parameters for embryo microinjection by observing early embryonic developmental features. We used the CasOT program to obtain highly specific guide RNAs (gRNAs) at the genome-wide level. According to the phenotypes of Hiwhite knockout strains, the pigmentation of larval stemmata, imaginal compound eyes, and ocelli differed from those of the wild type. These phenotypes were similar to those observed in other insects harbouring white gene mutations. In conclusion, our results described a detailed white genome editing process in black soldier flies, which lays a solid foundation for intensive research on the pigmentation pathway of the eyes and provides a methodological basis for further genome engineering applications in black soldier flies.

Amphiphilic Block Copolymers Containing Benzenesulfonyl Azide Groups as Visible Light-Responsive Drug Carriers for Image-Guided Delivery.

Nanoparticles (NPs) containing light-responsive polymers and imaging agents show great promise for controlled drug delivery. However, most light-responsive NPs rely on short-wavelength excitation, resulting in poor tissue penetration and potential cytotoxicity. Moreover, excessively sensitive NPs may prematurely release drugs during storage and circulation, diminishing their efficacy and causing off-target toxicity. Herein, we report visible-light-responsive NPs composed of an amphiphilic block copolymer containing responsive 4-acrylamide benzenesulfonyl azide (ABSA) and hydrophilic N,N'-dimethylacrylamide (DMA) units. The polymer pDMA-ABSA was loaded with the chemotherapy drug dasatinib and zinc tetraphenylporphyrin (ZnTPP). ZnTPP acted as an imaging reagent and a photosensitizer to reduce ABSA upon visible light irradiation, converting hydrophobic units to hydrophilic units and disrupting NPs to trigger drug release. These NPs enabled real-time fluorescence imaging in cells and exhibited synergistic chemophotodynamic therapy against multiple cancer cell lines. Our light-responsive NP platform holds great promise for controlled drug delivery and cancer theranostics, circumventing the limitations of traditional photosensitive nanosystems.

RNF34 functions in immunity and selective mitophagy by targeting MAVS for autophagic degradation.

Viral infection triggers the formation of mitochondrial antiviral signaling protein (MAVS) aggregates, which potently promote immune signaling. Autophagy plays an important role in controlling MAVS-mediated antiviral signaling; however, the exact molecular mechanism underlying the targeted autophagic degradation of MAVS remains unclear. Here, we investigated the mechanism by which RNF34 regulates immunity and mitophagy by targeting MAVS. RNF34 binds to MAVS in the mitochondrial compartment after viral infection and negatively regulates RIG-I-like receptor (RLR)-mediated antiviral immunity. Moreover, RNF34 catalyzes the K27-/K29-linked ubiquitination of MAVS at Lys 297, 311, 348, and 362 Arg, which serves as a recognition signal for NDP52-dependent autophagic degradation. Specifically, RNF34 initiates the K63- to K27-linked ubiquitination transition on MAVS primarily at Lys 311, which facilitates the autophagic degradation of MAVS upon RIG-I stimulation. Notably, RNF34 is required for the clearance of damaged mitochondria upon viral infection. Thus, we elucidated the mechanism by which RNF34-mediated autophagic degradation of MAVS regulates the innate immune response, mitochondrial homeostasis, and infection.

Supramolecular Self-Assembly in Living Cells.

Supramolecular interactions rely on non-covalent forces, such as hydrophobic effects, hydrogen-bonding, and electrostatic interactions, which govern many intracellular biological pathways. In cellulo supramolecular self-assembly is mainly based on host-guest interactions, changes in pH, enzymes, and polymerization-induced self-assembly to accurately induce various unnatural reactions without disturbing natural biological processes. This process can produce synthetic biocompatible macromolecules to control cell properties and regulate biological functions, such as cell proliferation and differentiation. This Minireview focuses on the latest reports in the field of in cellulo supramolecular self-assembly and anticipates future advances regarding its activation in response to internal and external stimuli, such as pH changes, reactive oxygen species, and enzymes, as well as external light illumination.

C=C Bond Oxidative Cleavage of BODIPY Photocages by Visible Light.

Photocages for protection and the controlled release of bioactive compounds have been widely investigated. However, the vast majority of these photocages employ the cleavage of single bonds and high-energy ultraviolet light. The construction of a photoactivation system that uses visible light to cleave unsaturated bonds still remains a challenge. Herein, we report a regioselective oxidative cleavage of C=C bonds from a boron-dipyrrolemethene (BODIPY)-based photocage by illumination at 630 nm, resulting in a free aldehyde and a thiol fluorescent probe. This strategy was demonstrated in live HeLa cells, and the generated α-formyl-BODIPY allowed real-time monitoring of aldehyde release in the cells. In particular, it is shown that a mannose-functionalized photocage can target HepG2 cells.

PM2.5 induces endothelial dysfunction via activating NLRP3 inflammasome.

PM2.5 (particulate matter <2.5 µm in diameter) is proven to contribute to the development of atherosclerosis. Endothelial cell dysfunction is the initial step of atherosclerosis. The underlying mechanisms of endothelial cell damage exposed to PM2.5 are still obscure. In our study, PM2.5 was administrated to C57BL/6 male mice by intranasal instillation for 2 weeks. Human umbilical vein endothelial cells (HUVECs) were also treated with PM2.5 to evaluate the adverse effect in vitro. The immunohistochemical staining of aortas showed that the expressions of proinflammatory cytokines and endothelial adhesion markers were significantly increased in PM2.5-exposed mice than that in saline-exposed mice. In vitro, PM2.5 could inhibit HUVECs viability and impair cell migration in a concentration-dependent manner. Besides, PM2.5 exposure downregulated eNOS expression while upregulated reactive oxygen species (ROS) levels. Mechanistically, PM2.5 activated the NLRP3 inflammasome in HUVECs while knockdown of NLRP3 could effectively reverse the downregulation of eNOS expression and production of ROS after PM2.5 exposure. In summary, our data showed that PM2.5 could cause endothelial dysfunction, and probably via NLRP3 inflammasome activation.

Bioorthogonal Swarming: In Situ Generation of Dendrimers.

With the aid of bioorthogonal chemistry, we demonstrate the fabrication of synthetic dendrimers in situ around living cells. Using tetrazine dienophile and aminooxyl/hydrazide aldehyde chemistries, the density of functional groups on the dendrimers exponentially amplified intensities of fluorescent markers in antibody-targeted live cell imaging. This novel "swarming" approach highlights the power of bioorthogonal chemistry and provides a route to non-natural chemical structures on cells, paving the way for the generation of various artificial cellular nanostructures and scaffolds.

Long-term coexistence of SARS-CoV-2 with antibody response in COVID-19 patients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causing coronavirus disease 2019 (COVID-19) has spread worldwide. Whether antibodies are important for the adaptive immune responses against SARS-CoV-2 infection needs to be determined. Here, 26 cases of COVID-19 in Jinan, China, were examined and shown to be mild or with common clinical symptoms, and no case of severe symptoms was found among these patients. Strikingly, a subset of these patients had SARS-CoV-2 and virus-specific IgG coexist for an unexpectedly long time, with two cases for up to 50 days. One COVID-19 patient who did not produce any SARS-CoV-2-bound IgG successfully cleared SARS-CoV-2 after 46 days of illness, revealing that without antibody-mediated adaptive immunity, innate immunity alone may still be powerful enough to eliminate SARS-CoV-2. This report may provide a basis for further analysis of both innate and adaptive immunity in SARS-CoV-2 clearance, especially in nonsevere cases.