Development and Evaluation of a Novel Antibacterial Wound Dressing: A Powder Preparation Based on Cross-Linked Pullulan with Polyhexamethylene Biguanide for Hydrogel-Transition in Advanced Wound Management and Infection Control.

As antibiotic resistance increasingly undermines traditional infection management strategies, there is a critical demand for innovative wound care solutions that address these emerging challenges. This study introduces a novel antibacterial wound dressing based on Cross-Linked Pullulan (Pul) and Polyhexamethylene Biguanide (PHMB) for enhanced wound management and infection control. The dressing's adsorption rate reached 200% of its original weight within 30 min, exceeded 300% after 5 h, and exhibited significant non-Newtonian fluid properties. The dressings were able to release the loaded medication completely within 20 min; additionally, the dressing demonstrated significant antibacterial activity against a broad spectrum of bacteria. Significantly, the therapeutic effects of the Pul-PHMB/GP dressing were evaluated in a mouse model. Compared to untreated wounds, wounds treated with Pul-PHMB/GP exhibited a significant gelation process within 5 min post-treatment and showed a significant increase in wound healing rate within 12 days. This powder preparation overcomes the limitations associated with liquid and gel dressings, notably in storage and precise application, preventing the premature expansion or dissolution often caused by PHMB in high-humidity environments. The powder form can transform into a gel upon contact with wound exudate, ensuring accurate coverage of irregular wounds, such as those from burns or pressure sores, and offers excellent chemical and physical stability in a dry state, which facilitates storage and transport. This makes the dressing particularly suitable for emergency medical care and precision therapy, significantly improving the efficiency and adaptability of wound treatment and providing robust support for clinical treatments and emergency responses.

Database-aided ultrahigh-performance liquid chromatography Q-Exactive-Orbitrap tandem mass spectrometry putatively identifies 16 unexpected compounds and three anticounterfeiting pharmacopoeia quality markers for Perillae Fructus.

RATIONALE: Perillae Fructus (PF) is a common traditional Chinese medicine (TCM) for the treatment of asthma. It has not been effectively characterized by rosmarinic acid (RosA), which is currently designed as the sole quality indicator in the Chinese Pharmacopoeia. METHODS: This study introduced a database-aided ultrahigh-performance liquid chromatography equipped with quadrupole-Exactive-Orbitrap mass spectrometry (UHPLC/Q-Exactive-Orbitrap MS/MS) technology to putatively identify the compounds in PF, followed by literature research, quantum chemical calculation, and molecular docking to screen potential quality markers (Q-markers) of PF. RESULTS: A total of 27 compounds were putatively identified, 16 of which had not been previously found from PF. In particular, matrine, scopolamine, and RosA showed relatively high levels of content, stability, and drug-likeness. They exhibited interactions with the asthma-related target and demonstrated the TCM properties of PF. CONCLUSIONS: The database-aided UHPLC/Q-Exactive-Orbitrap MS/MS can identify at least 27 compounds in PF. Of these, 16 compounds are unexpected, and three compounds (matrine, scopolamine, and RosA) should be considered anticounterfeiting pharmacopoeia Q-markers of PF.

Enhanced Thermal Stability of Carbonyl Iron Nanocrystalline Microwave Absorbents by Pinning Grain Boundaries with SiBaFe Alloy Nanoparticles.

Nanocrystalline carbonyl iron (CI) particles are promising microwave absorbents at elevated temperature, whereas their excessive grain boundary energy leads to the growth of nanograins and a deterioration in permeability. In this work, we report a strategy to enhance the thermal stability of the grains and microwave absorption of CI particles by doping a SiBaFe alloy. Grain growth was effectively inhibited by the pinning effect of SiBaFe alloy nanoparticles at the grain boundaries. After heat treatment at 600 °C, the grain size of CI particles increased from ~10 nm to 85.1 nm, while that of CI/SiBaFe particles was only 32.0 nm; with the temperature rising to 700 °C, the grain size of CI particles sharply increased to 158.1 nm, while that of CI/SiBaFe particles was only 40.8 nm. Excellent stability in saturation magnetization and microwave absorption was also achieved in CI/SiBaFe particles. After heat treatment at 600 °C, the flaky CI/SiBaFe particles exhibited reflection loss below -10 dB over 7.01~10.11 GHz and a minimum of -14.92 dB when the thickness of their paraffin-based composite was 1.5 mm. We provided a low-cost and efficient kinetic strategy to stabilize the grain size in nanoscale and microwave absorption for nanocrystalline magnetic absorbents working at elevated temperature.

Bimetallic MnZn-MOF-74 with enhanced percentage of MnIII: Efficiently catalytic activity for direct oxidative carboxylation of olefins to cyclic carbonates under mild and solvent-free condition.

Multi-functional MOF catalyst with oxidative- and acid- centers showed potential in olefins oxidative carboxylation to cyclic carbonates directly. In this work, a series of bimetallic MnZn-MOF-74 with different molar ratios of Mn and Zn were synthesized successfully through a one-pot facile method. Thoroughly characterization indicated that the existence of Zn regulated the valance state distribution of Mn in the obtained MnZn-MOF-74. Mn99.3Zn0.7-MOF-74 with the highest ratio of MnIII (61.3 %) performed the most efficient activity for olefin direct tandem oxidative carboxylation reaction using aqueous tert-butyl hydroperoxide oxidant under solvent-free condition of 90 °C, 1.0 MPa CO2 and 4 h. Mn99.3Zn0.7-MOF-74 also showed satisfactory versatility and recyclability. Based on the experiments, a feasible mechanism was presented. Thanks to the high ratio of active MnIII as main oxidative center, the coordination unsaturated bimetal Mn and Zn as Lewis-acid sites, O2- of metal - O as Lewis-base sites and combined effect with Bu4NBr cocatalyst, Mn99.3Zn0.7-MOF-74 presented efficient performance for the direct synthesis of cyclic carbonates from olefins. The metal Zn in MOF can regulate the valance state distribution of Mn and result in efficient catalytic property, presenting a potential avenue for direct oxidative carboxylation reaction of olefins to cyclic carbonates synthesis.

Applications, challenges, and solutions of unmanned aerial vehicles in smart city using blockchain.

Real-time data gathering, analysis, and reaction are made possible by this information and communication technology system. Data storage is also made possible by it. This is a good move since it enhances the administration and operation services essential to any city's efficient operation. The idea behind "smart cities" is that information and communication technology (ICTs) need to be included in a city's routine activities in order to gather, analyze, and store enormous amounts of data in real-time. This is helpful since it makes managing and governing urban areas easier. The "drone" or "uncrewed aerial vehicle" (UAV), which can carry out activities that ordinarily call for a human driver, serves as an example of this. UAVs could be used to integrate geospatial data, manage traffic, keep an eye on objects, and help in an emergency as part of a smart urban fabric. This study looks at the benefits and drawbacks of deploying UAVs in the conception, development, and management of smart cities. This article describes the importance and advantages of deploying UAVs in designing, developing, and maintaining in smart cities. This article overviews UAV uses types, applications, and challenges. Furthermore, we presented blockchain approaches for addressing the given problems for UAVs in smart research topics and recommendations for improving the security and privacy of UAVs in smart cities. Furthermore, we presented Blockchain approaches for addressing the given problems for UAVs in smart cities. Researcher and graduate students are audience of our article.

Selenium Lessens Osteoarthritis by Protecting Articular Chondrocytes from Oxidative Damage through Nrf2 and NF-κB Pathways.

Osteoarthritis (OA) causes joint pain and disability due to the abnormal production of inflammatory cytokines and reactive oxygen species (ROS) in chondrocytes, leading to cell death and cartilage matrix destruction. Selenium (Se) intake can protect cells against oxidative damage. It is still unknown whether Se supplementation is beneficial for OA. This study investigated the effects of Se on sodium iodoacetate (MIA)-imitated OA progress in human chondrocyte cell line (SW1353 cells) and rats. The results showed that 0.3 µM of Se treatment could protect SW1353 cells from MIA-induced damage by the Nrf2 pathway by promoting the gene expression of glutathione-synthesis-related enzymes such as the glutamate-cysteine ligase catalytic subunit, the glutamate-cysteine ligase modifier subunit, and glutathione synthetase. In addition, glutathione, superoxide dismutase, glutathione peroxidase, and glutathione reductase expressions are also elevated to eliminate excessive ROS production. Moreover, Se could downregulate NF-κB, leading to a decrease in cytokines, matrix proteases, and glycosaminoglycans. In the rats, MIA-induced cartilage loss was lessened after 2 weeks of Se supplementation by oral gavage; meanwhile, glutathione synthesis was increased, and the expressions of pro-inflammatory cytokines were decreased. These results suggest that Se intake is beneficial for OA due to its effects of decreasing cartilage loss by enhancing antioxidant capacity and reducing inflammation.

RNA-guided genome engineering: paradigm shift towards transposons.

CRISPR-Cas systems revolutionized the genome engineering field but need to induce double-strand breaks (DSBs) and may be difficult to deliver due to their large protein size. Tn7-like transposons such as CRISPR-associated transposons (CASTs) can be repurposed for RNA-guided DSB-free integration, and obligate mobile element guided activity (OMEGA) proteins of the IS200/IS605 transposon family have been developed as hypercompact RNA-guided genome editing tools. CASTs and OMEGA are exciting, innovative genome engineering tools that can improve the precision and efficiency of editing. This review explores the recent developments and uses of CASTs and OMEGA in genome editing across prokaryotic and eukaryotic cells. The pros and cons of these transposon-based systems are deliberated in comparison to other CRISPR systems.

Development of validated sandwich ELISA for detecting peanut allergen Ara h 3 in food.

Peanut is an important food that can cause food allergies, often leading to moderate and severe allergic symptoms such as skin rashes, asthma, and even anaphylactic shock.Research indicates that Ara h 3 is one of the major peanut allergen. In order to establish a simple analytical method for detecting Ara h 3, we developed a sandwich enzyme-linked immunosorbent assay (ELISA) with antibodies that were induced from purified Ara h 3. The experimental results showed that the purified Ara h 3 had good purity, and we successfully prepared capture and detection antibodies. The method established in this study exhibited high specificity and did not cross-react with soybeans, cashew nuts, and sesame. For validation, including precision, recovery and sensitivity were in good condition. We also detected the Ara h 3 in peanut related foods. Overall, the ELISA developed in this study is a reliable method for Ara h 3 detection.

Placebo and Nocebo Responses in Pharmacological Trials of Tic Disorders: A Meta-Analysis.

BACKGROUND: Clinical trials of new drugs for tic disorders (TD) often fail to yield positive results. Placebo and nocebo responses play a vital role in interpreting the outcomes of randomized controlled trials (RCTs), yet these responses in RCTs of TD remain unexplored. OBJECTIVE: The aim was to assess the magnitude of placebo and nocebo responses in RCTs of pharmacological interventions for TD and identify influencing factors. METHODS: A systematic search of the Embase, Medline, Cochrane Central Register of Controlled Trials, and PsycINFO databases was conducted. Eligible studies were RCTs that compared active pharmacological agents with placebos. Placebo response was defined as the change from baseline in TD symptom severity in the placebo group, and nocebo response as the proportion experiencing adverse events (AEs) in this group. Subgroup analysis and meta-regression were performed to explore modifying factors. RESULTS: Twenty-four trials involving 2222 participants were included in this study. A substantial placebo response in TD symptom severity was identified, with a pooled effect size of -0.79 (95% confidence interval [CI] -0.99 to -0.59; I2 = 67%). Forty-four percent (95% CI 27% to 63%; I2 = 92%) of patients experienced AEs while taking inert pills. Sample size, study design, and randomization ratio were correlated with changes in placebo and nocebo responses. CONCLUSION: There were considerable placebo and nocebo responses in TD clinical trials. These results are of great relevance for the design of future trials and for clinical practice in TD. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration ID CRD42023388397. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Enhanced Calvarial Bone Repair Using ASCs Engineered with RNA-Guided Split dCas12a System that Co-Activates Sox 5, Sox6, and Long Non-Coding RNA H19.

Healing of large calvarial bone defects remains challenging. An RNA-guided Split dCas12a system is previously harnessed to activate long non-coding RNA H19 (lncRNA H19, referred to as H19 thereafter) in bone marrow-derived mesenchymal stem cells (BMSCs). H19 activation in BMSCs induces chondrogenic differentiation, switches bone healing pathways, and improves calvarial bone repair. Since adipose-derived stem cells (ASCs) can be harvested more easily in large quantity, here it is aimed to use ASCs as an alternative cell source. However, H19 activation alone using the Split dCas12a system in ASCs failed to elicit evident chondrogenesis. Therefore, split dCas12a activators are designed more to co-activate other chondroinductive transcription factors (Sox5, Sox6, and Sox9) to synergistically potentiate differentiation. It is found that co-activation of H19/Sox5/Sox6 in ASCs elicited more potent chondrogenic differentiation than activation of Sox5/Sox6/Sox9 or H19 alone. Co-activating H19/Sox5/Sox6 in ASCs significantly augmented in vitro cartilage formation and in vivo calvarial bone healing. These data altogether implicated the potentials of the Split dCas12a system to trigger multiplexed gene activation in ASCs for differentiation pathway reprogramming and tissue regeneration.

Visualizing the global trends of peptides in wound healing through an in-depth bibliometric analysis.

Wound healing is a complicated and multistage biological process for the repair of damaged/injured tissues, which requires intelligent designs to provide comprehensive and convenient treatment. Peptide-based wound dressings have received extensive attention for further development and application due to their excellent biocompatibility and multifunctionality. However, the current lack of intuitive analysis of the development trend and research hotspots of peptides applied in wound healing, as well as detailed elaboration of possible research hotspots, restricted obtaining a comprehensive understanding and development in this field. The present study analysed publications from the Web of Science (WOS) Core Collection database and visualized the hotspots and current trends of peptide research in wound healing. Data between January 1st, 2003, and December 31st, 2022, were collected and subjected to a bibliometric analysis. The countries, institutions, co-authorship, co-citation reference, and co-occurrence of keywords in this subject were examined using VOSviewer and CiteSpace. We provided an intuitive, timely, and logical overview of the development prospects and challenges of peptide application in wound healing and some solutions to the major obstacles, which will help researchers gain insights into the investigation of this promising field.

Trabecular Bone Microarchitecture Evaluation in an Osteoporosis Mouse Model.

Bone microstructure refers to the arrangement and quality of bone tissue at the microscopic level. Understanding the bone microstructure of the skeleton is crucial for gaining insight into the pathophysiology of osteoporosis and improving its treatment. However, handling bone samples can be complex due to their hard and dense properties. Secondly, specialized software makes image processing and analysis difficult. In this protocol, we present a cost-effective and easy-to-use solution for trabecular bone microstructure analysis. Detailed steps and precautions are provided. Micro-CT is a non-destructive three-dimensional (3D) imaging technique that provides high-resolution images of trabecular bone structure. It allows for the objective and quantitative evaluation of bone quality, which is why it is widely regarded as the gold standard method for bone quality assessment. However, histomorphometry remains indispensable as it offers crucial cellular-level parameters, bridging the gap between two-dimensional (2D) and 3D assessments of bone specimens. As for the histologic techniques, we chose to decalcify the bone tissue and then perform traditional paraffin embedding. In summary, combining these two methods can provide more comprehensive and accurate information on bone microstructure.

Bioactive peptides derived from Radix Angelicae sinensis inhibit ferroptosis in HT22 cells through direct Keap1-Nrf2 PPI inhibition.

The development of natural peptides as direct Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid2-related factor 2 (Nrf2) protein-protein interaction (PPI) inhibitors for antioxidant and anti-ferroptotic purposes has attracted increasing interest from chemists. Radix Angelicae sinensis (RAS) is a widely used traditional Chinese medicine with antioxidant capability. However, few studies have screened Keap1-Nrf2 PPI inhibitory RAS peptides (RASPs). This study optimized the extraction and hydrolysis protocols of RAS protein using response surface methodology coupled with Box-Behnken design. The molecular weight distribution of the prepared hydrolysates was analysed to obtain active fractions. Subsequently, ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry was employed to identify RASPs. Various in vitro and in silico assays were conducted to evaluate the antioxidant and anti-ferroptotic effects of RASPs. The results revealed that at least 50 RASPs could be obtained through the optimized protocols. RASPs containing active residues effectively scavenged 2,2-diphenyl-1-picrylhydrazyl radical and 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid radical cation. They also showed cytoprotective effect against erastin-induced ferroptosis in HT22 cells, which was characterized by the activation of Nrf2 and weakened under the incubation of an Nrf2 inhibitor. Moreover, RASPs could bind to Keap1 and then dissociate Nrf2 in molecular dynamics simulations. In conclusion, RASPs exhibit antioxidant activity through hydrogen atom transfer and electron transfer mechanisms. Importantly, they also inhibit ferroptosis by directly inhibiting Keap1-Nrf2 PPI.

Stimulus-responsive peptide hydrogels: a safe and least invasive administration approach for tumor treatment.

Tumours, with increasing mortality around the world, have bothered human beings for decades. Enhancing the targeting of antitumor drugs to tumour tissues is the key to enhancing their antitumor effects. The tumour microenvironment is characterised by a relatively low pH, overexpression of certain enzymes, redox imbalance, etc. Therefore, smart drug delivery systems that respond to the tumour microenvironment have been proposed to selectively release antitumor drugs. Among them, peptide hydrogels as a local drug delivery system have received much attention due to advantages such as high biocompatibility, degradability and high water-absorbing capacity. The combination of peptide segments with different physiological functions allows for tumour targeting, self-aggregation, responsiveness, etc. Morphological and microstructural changes in peptide hydrogels can occur when utilising the inherent pathological microenvironment of tumours to trigger drug release, which endows such systems with limited adverse effects and improved therapeutic efficiency. Herein, this review outlined the driving forces, impact factors, and sequence design in peptide hydrogels. We also discussed the triggers to induce the transformation of peptide-based hydrogels in the tumour microenvironment and described the advancements of peptide-based hydrogels for local drug delivery in tumour treatment. Finally, we gave a brief perspective on the prospects and challenges in this field.

Wheel-structured Triboelectric Nanogenerators with Hyperelastic Networking for High-Performance Wave Energy Harvesting.

Developing clean and renewable energy sources is an important strategy to reduce carbon emission and achieve carbon neutrality. As one of the most promising clean energy sources, large-scale, and efficient utilization of ocean blue energy remains a challenging problem to be solved. In this work, a hyperelastic network of wheel-structured triboelectric nanogenerators (WS-TENGs) is demonstrated to efficiently harvest low-frequency and small-amplitude wave energy. Different from traditional designs of smooth shell, the external blades on the TENG allow tighter interaction between the wave and the device, which can roll on the water surface like a wheel, continuously agitating internal TENGs. Moreover, the hyperelastic networking structure can stretch and shrink like a spring with stored wave energy, further intensifying the roll of the device, and connecting the WS-TENGs to form a large-scale network. Multiple driving modes with synergistic effects can be realized under wave and wind excitations. Self-powered systems are fabricated based on the WS-TENG network, showing the capability of the device in real wave environment. The work provides a new driving paradigm that can further enhance the energy harvesting capability toward large-scale blue energy utilization based on TENGs.

Stepwise Assembly of Quinary Multivariate Metal-Organic Frameworks via Diversified Linker Exchange and Installation.

Multivariate MOFs (MTV-MOFs) constructed from multiple components with atomistic precision hold the promise for many fascinating developments in both fundamental sciences and applications. Sequential linker installation can be an effective method to introduce different functional linkers into an MOF that contains coordinatively unsaturated metal sites. However, in many cases, these linkers must be installed according to a specific sequence and the complete synthetic flexibility and freedom is yet to be realized. Here, we rationally decreased the size of the primary ligand used in NPF-300, a Zr-MOF with scu topology (NPF = Nebraska Porous Framework), and synthesized its isostructure, NPF-320. NPF-320 exhibits optimized pocket sizes which allow for the post-synthetic installation of three secondary linkers in all six permuted sequences via both linker exchange and installation, forming a final quinary MTV-MOF via single-crystal-to-single-crystal transformation. With the functionalization of the linkers from the quinary MOF system, one will be able to construct MTV-MOFs not only with variable porosity but also with unprecedented complexity and encoded synthetic sequence information. The utility of sequential linker installation was further demonstrated by the construction of a donor-acceptor pair-based energy transfer system.

Life cycle environmental impact assessment for battery-powered electric vehicles at the global and regional levels.

As an important part of electric vehicles, lithium-ion battery packs will have a certain environmental impact in the use stage. To analyze the comprehensive environmental impact, 11 lithium-ion battery packs composed of different materials were selected as the research object. By introducing the life cycle assessment method and entropy weight method to quantify environmental load, a multilevel index evaluation system was established based on environmental battery characteristics. The results show that the Li-S battery is the cleanest battery in the use stage. In addition, in terms of power structure, when battery packs are used in China, the carbon footprint, ecological footprint, acidification potential, eutrophication potential, human toxicity cancer and human toxicity noncancer are much higher than those in the other four regions. Although the current power structure in China is not conducive to the sustainable development of electric vehicles, the optimization of the power structure is expected to make electric vehicles achieve clean driving in China.

Rotablation for Octogenarians in a Modern Cathlab: Short- and Intermediate-Term Results.

Background: There are limited reports on the treatment of complex calcified lesions using rotational atherectomy (RA) in octogenarians, particularly in high-risk patients. Objective: To evaluate procedural and clinical outcomes of RA in octogenarians. Methods: Consecutive RA patients from 2010 to 2018 were selected from our catheterization laboratory database, stratified into two groups (≥ or < 80 years old), and analyzed. Results: A total of 411 patients (269 males and 142 females) with a mean age of 73.8 ± 11.3 years were enrolled, of whom 153 were ≥ 80 years old and 258 were < 80 years old. Most of the patients displayed high-risk features. The baseline Syntax scores were high in both groups, and most lesions were heavily calcified (96.1% vs. 97.3%, p = 0.969, respectively). The use of hemodynamic support intra-aortic balloon pump was more frequent in the octogenarians (21.6% vs. 11.6%, p = 0.007), but the RA completion rate was similarly high (95.9% vs. 99.1%, p = 0.842). There was no difference in acute complications. The total/cardiovascular (CV) death rate within one year was higher in the octogenarians, along with higher major adverse cardiovascular event (MACE)/CV MACE rates in the first month. Cox regression analysis showed that age ≥ 80 years, acute coronary syndrome, ischemic cardiomyopathy/shock, multi-vessel disease and serum creatinine were all predictors of MACE, and that these factors plus peripheral artery disease were predictors of all-cause mortality in these patients. Conclusions: RA is feasible with a very high success rate in high-risk octogenarians with complex anatomies, and with equal safety and no increase in complications. The higher rates of all-cause death and MACE were attributed to an older age and other traditional risk factors.

Joint Data Transmission and Energy Harvesting for MISO Downlink Transmission Coordination in Wireless IoT Networks.

The advent of simultaneous wireless information and power (SWIPT) has been regarded as a promising technique to provide power supplies for an energy sustainable Internet of Things (IoT), which is of paramount importance due to the proliferation of high data communication demands of low-power network devices. In such networks, a multi-antenna base station (BS) in each cell can be utilized to concurrently transmit messages and energies to its intended IoT user equipment (IoT-UE) with a single antenna under a common broadcast frequency band, resulting in a multi-cell multi-input single-output (MISO) interference channel (IC). In this work, we aim to find the trade-off between the spectrum efficiency (SE) and energy harvesting (EH) in SWIPT-enabled networks with MISO ICs. For this, we derive a multi-objective optimization (MOO) formulation to obtain the optimal beamforming pattern (BP) and power splitting ratio (PR), and we propose a fractional programming (FP) model to find the solution. To tackle the nonconvexity of FP, an evolutionary algorithm (EA)-aided quadratic transform technique is proposed, which recasts the nonconvex problem as a sequence of convex problems to be solved iteratively. To further reduce the communication overhead and computational complexity, a distributed multi-agent learning-based approach is proposed that requires only partial observations of the channel state information (CSI). In this approach, each BS is equipped with a double deep Q network (DDQN) to determine the BP and PR for its UE with lower computational complexity based on the observations through a limited information exchange process. Finally, with the simulation experiments, we verify the trade-off between SE and EH, and we demonstrate that, apart from the FP algorithm introduced to provide superior solutions, the proposed DDQN algorithm also shows its performance gain in terms of utility to be up to 1.23-, 1.87-, and 3.45-times larger than the Advantage Actor Critic (A2C), greedy, and random algorithms, respectively, in comparison in the simulated environment.

Split dCas12a activator for lncRNA H19 activation to enhance BMSC differentiation and promote calvarial bone healing.

Healing of large calvarial bone defects in adults is challenging. We previously showed that inducing chondrogenic differentiation of mesenchymal stem cells from bone marrow (BMSC) or adipose tissue (ASC) before implantation can switch the repair pathway and improve calvarial bone healing. Split dCas12a activator is a new CRISPR activation system comprising the amino (N) and carboxyl (C) fragments of dCas12a protein, each being fused with synthetic transcription activators at both termini. The split dCas12a activator was shown to induce programmable gene expression in cell lines. Here we exploited the split dCas12a activator to activate the expression of chondroinductive long non-coding RNA H19. We showed that co-expression of the split N- and C-fragments resulted in spontaneous dimerization, which elicited stronger activation of H19 than full-length dCas12a activator in rat BMSC and ASC. We further packaged the entire split dCas12a activator system (13.2 kb) into a hybrid baculovirus vector, which enhanced and prolonged H19 activation for at least 14 days in BMSC and ASC. The extended H19 activation elicited potent chondrogenic differentiation and inhibited adipogenesis. Consequently, the engineered BMSC promoted in vitro cartilage formation and augmented calvarial bone healing in rats. These data implicated the potentials of the split dCas12a activator for stem cell engineering and regenerative medicine.