Evolutional heterochromatin condensation delineates chromocenter formation and retrotransposon silencing in plants.

Heterochromatic condensates (chromocenters) are critical for maintaining the silencing of heterochromatin. It is therefore puzzling that the presence of chromocenters is variable across plant species. Here we reveal that variations in the plant heterochromatin protein ADCP1 confer a diversity in chromocenter formation via phase separation. ADCP1 physically interacts with the high mobility group protein HMGA to form a complex and mediates heterochromatin condensation by multivalent interactions. The loss of intrinsically disordered regions (IDRs) in ADCP1 homologues during evolution has led to the absence of prominent chromocenter formation in various plant species, and introduction of IDR-containing ADCP1 with HMGA promotes heterochromatin condensation and retrotransposon silencing. Moreover, plants in the Cucurbitaceae group have evolved an IDR-containing chimaera of ADCP1 and HMGA, which remarkably enables formation of chromocenters. Together, our work uncovers a coevolved mechanism of phase separation in packing heterochromatin and silencing retrotransposons.

Engineered Microrobots for Targeted Delivery of Bacterial Outer Membrane Vesicles (OMV) in Thrombus Therapy.

In the realm of thrombosis treatment, bioengineered outer membrane vesicles (OMVs) offer a novel and promising approach, as they have rich content of bacterial-derived components. This study centers on OMVs derived from Escherichia coli BL21 cells, innovatively engineered to encapsulate the staphylokinase-hirudin fusion protein (SFH). SFH synergizes the properties of staphylokinase (SAK) and hirudin (HV) to enhance thrombolytic efficiency while reducing the risks associated with re-embolization and bleeding. Building on this foundation, this study introduces two cutting-edge microrobotic platforms: SFH-OMV@H for venous thromboembolism (VTE) treatment, and SFH-OMV@MΦ, designed specifically for cerebral venous sinus thrombosis (CVST) therapy. These platforms have demonstrated significant efficacy in dissolving thrombi, with SFH-OMV@H showcasing precise vascular navigation and SFH-OMV@MΦ effectively targeting cerebral thrombi. The study shows that the integration of these bioengineered OMVs and microrobotic systems marks a significant advancement in thrombosis treatment, underlining their potential to revolutionize personalized medical approaches to complex health conditions.

Swarm Autonomy: From Agent Functionalization to Machine Intelligence.

Swarm behaviors are common in nature, where individual organisms collaborate via perception, communication, and adaptation. Emulating these dynamics, large groups of active agents can self-organize through localized interactions, giving rise to complex swarm behaviors, which exhibit potential for applications across various domains. This review presents a comprehensive summary and perspective of synthetic swarms, to bridge the gap between the microscale individual agents and potential applications of synthetic swarms. It is begun by examining active agents, the fundamental units of synthetic swarms, to understand the origins of their motility and functionality in the presence of external stimuli. Then inter-agent communications and agent-environment communications that contribute to the swarm generation are summarized. Furthermore, the swarm behaviors reported to date and the emergence of machine intelligence within these behaviors are reviewed. Eventually, the applications enabled by distinct synthetic swarms are summarized. By discussing the emergent machine intelligence in swarm behaviors, insights are offered into the design and deployment of autonomous synthetic swarms for real-world applications.

Magnetically Powered Immunogenic Macrophage Microrobots for Targeted Multimodal Cancer Therapy.

Motile microrobots open a new realm for disease treatment. However, the concerns of possible immune elimination, targeted capability and limited therapeutic avenue of microrobots constrain its practical biomedical applications. Herein, a biogenic macrophage-based microrobot loaded with magnetic nanoparticles and bioengineered bacterial outer membrane vesicles (OMVs), capable of magnetic propulsion, tumor targeting, and multimodal cancer therapy is reported. Such cell robots preserve intrinsic properties of macrophages for tumor suppression and targeting, and bioengineered OMVs for antitumor immune regulation and fused anticancer peptides. Cell robots display efficient magnetic propulsion and directional migration in the confined space. In vivo tests show that cell robots can accumulate at the tumor site upon magnetic manipulation, coupling with tumor tropism of macrophages to greatly improve the efficacy of its multimodal therapy, including tumor inhibition of macrophages, immune stimulation, and antitumor peptides of OMVs. This technology offers an attractive avenue to design intelligent medical microrobots with remote manipulation and multifunctional therapy capabilities for practical precision treatment.

Bioengineered bacterial outer membrane vesicles encapsulated Polybia-mastoparan I fusion peptide as a promising nanoplatform for bladder cancer immune-modulatory chemotherapy.

Background: Nanosized bacterial outer membrane vesicles (OMVs) secreted by Gram-negative bacteria have emerged as a novel antitumor nanomedicine reagent due to their immunostimulatory properties. The encapsulated bacterial composition in OMVs can be edited via manipulating bioengineering technology on paternal bacteria, allowing us to design an ingenious antitumor platform by loading the Polybia-mastoparan I (MPI) fusion peptide into OMVs. Methods: OMVs containing the MPI fusion peptide were obtained from bioengineered Escherichia coli transformed with recombinant plasmid. The antitumor efficacy of bioengineered OMVs in vitro was verified by performing cell viability and wound-healing and apoptosis assays using MB49 and UMUC3 cells, respectively. Subcutaneous MB49 tumor-bearing mice were involved to investigate the tumor inhibition ability of bioengineered OMVs. Moreover, the activated immune response in tumor and the biosafety were also evaluated in detail. Results: The resulting OMVs had the successful encapsulation of MPI fusion peptides and were subjected to physical characterization for morphology, size, and zeta potential. Cell viabilities of bladder cancer cells including MB49 and UMUC3 rather than a non-carcinomatous cell line (bEnd.3) were decreased when incubated with bioengineered OMVs. In addition, bioengineered OMVs restrained migration and induced apoptosis of bladder cancer cells. With intratumor injection of bioengineered OMVs, growths of subcutaneous MB49 tumors were significantly restricted. The inherent immunostimulation of OMVs was demonstrated to trigger maturation of dendritic cells (DCs), recruitment of macrophages, and infiltration of cytotoxic T lymphocytes (CTLs), resulting in the increased secretion of pro-inflammatory cytokines (IL-6, TNF-α, and IFN-γ). Meanwhile, several lines of evidence also indicated that bioengineered OMVs had satisfactory biosafety. Conclusion: Bioengineered OMVs fabricated in the present study were characterized by strong bladder cancer suppression and great biocompatibility, providing a new avenue for clinical bladder cancer therapy.

Magnetic-Powered Janus Cell Robots Loaded with Oncolytic Adenovirus for Active and Targeted Virotherapy of Bladder Cancer.

A unique robotic medical platform is designed by utilizing cell robots as the active "Trojan horse" of oncolytic adenovirus (OA), capable of tumor-selective binding and killing. The OA-loaded cell robots are fabricated by entirely modifying OA-infected 293T cells with cyclic arginine-glycine-aspartic acid tripeptide (cRGD) to specifically bind with bladder cancer cells, followed by asymmetric immobilization of Fe3 O4 nanoparticles (NPs) on the cell surface. OA can replicate in host cells and induce cytolysis to release the virus progeny to the surrounding tumor sites for sustainable infection and oncolysis. The asymmetric coating of magnetic NPs bestows the cell robots with effective movement in various media and wireless manipulation with directional migration in a microfluidic device and bladder mold under magnetic control, further enabling steerable movement and prolonged retention of cell robots in the mouse bladder. The biorecognition of cRGD and robust, controllable propulsion of cell robots work synergistically to greatly enhance their tissue penetration and anticancer efficacy in the 3D cancer spheroid and orthotopic mouse bladder tumor model. Overall, this study integrates cell-based microrobots with virotherapy to generate an attractive robotic system with tumor specificity, expanding the operation scope of cell robots in biomedical community.

Phase-separated condensate-aided enrichment of biomolecular interactions for high-throughput drug screening in test tubes.

Modification-dependent and -independent biomolecular interactions, including protein-protein, protein-DNA/RNA, protein-sugar, and protein-lipid interactions, play crucial roles in all cellular processes. Dysregulation of these biomolecular interactions or malfunction of the associated enzymes results in various diseases; therefore, these interactions and enzymes are attractive targets for therapies. High-throughput screening can greatly facilitate the discovery of drugs for these targets. Here, we describe a biomolecular interaction detection method, called phase-separated condensate-aided enrichment of biomolecular interactions in test tubes (CEBIT). The readout of CEBIT is the selective recruitment of biomolecules into phase-separated condensates harboring their cognate binding partners. We tailored CEBIT to detect various biomolecular interactions and activities of biomolecule-modifying enzymes. Using CEBIT-based high-throughput screening assays, we identified known inhibitors of the p53/MDM2 (MDM2) interaction and of the histone methyltransferase, suppressor of variegation 3-9 homolog 1 (SUV39H1), from a compound library. CEBIT is simple and versatile, and is likely to become a powerful tool for drug discovery and basic biomedical research.

Mitotic Implantation of the Transcription Factor Prospero via Phase Separation Drives Terminal Neuronal Differentiation.

Compacted heterochromatin blocks are prevalent in differentiated cells and present a barrier to cellular reprogramming. It remains obscure how heterochromatin remodeling is orchestrated during cell differentiation. Here we find that the evolutionarily conserved homeodomain transcription factor Prospero (Pros)/Prox1 ensures neuronal differentiation by driving heterochromatin domain condensation and expansion. Intriguingly, in mitotically dividing Drosophila neural precursors, Pros is retained at H3K9me3+ pericentromeric heterochromatin regions of chromosomes via liquid-liquid phase separation (LLPS). During mitotic exit of neural precursors, mitotically retained Pros recruits and concentrates heterochromatin protein 1 (HP1) into phase-separated condensates and drives heterochromatin compaction. This establishes a transcriptionally repressive chromatin environment that guarantees cell-cycle exit and terminal neuronal differentiation. Importantly, mammalian Prox1 employs a similar "mitotic-implantation-ensured heterochromatin condensation" strategy to reinforce neuronal differentiation. Together, our results unveiled a new paradigm whereby mitotic implantation of a transcription factor via LLPS remodels H3K9me3+ heterochromatin and drives timely and irreversible terminal differentiation.

Mitochondrion-processed TERC regulates senescence without affecting telomerase activities.

Mitochondrial dysfunctions play major roles in ageing. How mitochondrial stresses invoke downstream responses and how specificity of the signaling is achieved, however, remains unclear. We have previously discovered that the RNA component of Telomerase TERC is imported into mitochondria, processed to a shorter form TERC-53, and then exported back to the cytosol. Cytosolic TERC-53 levels respond to mitochondrial functions, but have no direct effect on these functions, suggesting that cytosolic TERC-53 functions downstream of mitochondria as a signal of mitochondrial functions. Here, we show that cytosolic TERC-53 plays a regulatory role on cellular senescence and is involved in cognition decline in 10 months old mice, independent of its telomerase function. Manipulation of cytosolic TERC-53 levels affects cellular senescence and cognition decline in 10 months old mouse hippocampi without affecting telomerase activity, and most importantly, affects cellular senescence in terc-/- cells. These findings uncover a senescence-related regulatory pathway with a non-coding RNA as the signal in mammals.

Mitochondrial Trafficking and Processing of Telomerase RNA TERC.

Mitochondrial dysfunctions play major roles in many diseases. However, how mitochondrial stresses are relayed to downstream responses remains unclear. Here we show that the RNA component of mammalian telomerase TERC is imported into mitochondria, processed to a shorter form TERC-53, and then exported back to the cytosol. We found that the import is regulated by PNPASE, and the processing is controlled by mitochondrion-localized RNASET2. Cytosolic TERC-53 levels respond to changes in mitochondrial functions but have no direct effect on these functions. These findings uncover a mitochondrial RNA trafficking pathway and provide a potential mechanism for mitochondria to relay their functional states to other cellular compartments.

Mammalian mitochondrial RNAs are degraded in the mitochondrial intermembrane space by RNASET2.

Mammalian mitochondrial genome encodes a small set of tRNAs, rRNAs, and mRNAs. The RNA synthesis process has been well characterized. How the RNAs are degraded, however, is poorly understood. It was long assumed that the degradation happens in the matrix where transcription and translation machineries reside. Here we show that contrary to the assumption, mammalian mitochondrial RNA degradation occurs in the mitochondrial intermembrane space (IMS) and the IMS-localized RNASET2 is the enzyme that degrades the RNAs. This provides a new paradigm for understanding mitochondrial RNA metabolism and transport.

Protein adsorption enhanced radio-frequency heating of silica nanoparticles.

Measurements of specific-absorption-rate (SAR) of silica 30, 50, and 100 nm nanoparticles (NP) suspended in water were carried out at 30 MHz in 7 kV/m radio-frequency (rf) electric field. Size dependent, NP-suspension interface related heating of silica NP was observed. To investigate a possible mechanism of heating, bovine serum albumin was adsorbed on the surface of silica NPs in suspension. It resulted in significant enhancement of SAR when compared to bare silica NPs. A calorimetric and rf loss model was used to calculate effective conductivity of silica NP with/without adsorbed albumin as a function of silica size and albumin concentration.

A method to measure specific absorption rate of nanoparticles in colloidal suspension using different configurations of radio-frequency fields.

We report a method for characterization of the efficiency of radio-frequency (rf) heating of nanoparticles (NPs) suspended in an aqueous medium. Measurements were carried out for water suspended 5 nm superparamagnetic iron-oxide NPs with 30 nm dextran matrix for three different configurations of rf electric and magnetic fields. A 30 MHz high-Q resonator was designed to measure samples placed inside a parallel plate capacitor and solenoid coil with or without an rf electric field shield. All components of rf losses were analyzed and rf electric and magnetic field induced heating of NPs and the dispersion medium was determined and discussed.

Use of the radiofrequency-intermodulation distortion technique to investigate intrinsic nonlinearity at the electrode-electrolyte interface.

We report on investigations of nonlinear radiofrequency responses of electrolytes with Na(+) and Cl(-) ions placed within gold electrodes of a capacitor. The sample was part of a frequency-adjustable inductance-capacitance-resistance (LCR) parallel resonant circuit, and measurements were carried out using the two frequencies intermodulation distortion technique. We employed double layer model to analyze the observed nonlinearities and their dependence on ionic concentration. Electrode-electrolyte interface polarization was found to be a predominant cause of this intrinsic nonlinearity and to be dependent on electrolytic ion concentration. We also measured and calculated coefficients of resistive and capacitive components of the observed nonlinearity.