ABSTRACT
Helicases, which utilize ATP hydrolysis to separate nucleic acid duplexes, play crucial roles in DNA and RNA replication, repair, recombination, and transcription. Categorized into the major groups superfamily 1 (SF1) and superfamily 2 (SF2), alongside four minor groups, these proteins exhibit a conserved catalytic core indicative of a shared evolutionary origin while displaying functional diversity through interactions with various substrates. This review summarizes the structures, functions and mechanisms of SF1 and SF2 helicases, with an emphasis on conserved ATPase sites and RecA-like domains essential for their enzymatic and nucleic acid binding capabilities. It highlights the unique 1B and 2B domains in SF1 helicases and their impact on enzymatic activity. The DNA unwinding process is detailed, covering substrate recognition, ATP hydrolysis, and conformational changes, while addressing debates over the active form of UvrD helicase and post-unwinding dissociation. More importantly, this review discusses the biotechnological potential of helicases in emerging technologies such as nanopore sequencing, protein sequencing, and isothermal amplification, focusing on their use in pathogen detection, biosensor enhancement, and cancer treatment. As understanding deepens, innovative applications in genome editing, DNA sequencing, and synthetic biology are anticipated.
ABSTRACT
Ultrasonic welding (USW) of thermoplastics plays a significant role in the automobile industry. In this study, the effect of the welding time on the joint strength of ultrasonically welded acrylonitrile-butadiene-styrene (ABS) and the weld formation mechanism were investigated. The results showed that the peak load firstly increased to a maximum value of 3.4 kN and then dropped with further extension of the welding time, whereas the weld area increased continuously until reaching a plateau. The optimal welding variables for the USW of ABS were a welding time of 1.3 s with a welding pressure of 0.13 MPa. Interfacial failure and workpiece breakage were the main failure modes of the joints. The application of real-time horn displacement into a finite element model could improve the simulation accuracy of weld formation. The simulated results were close to the experimental results, and the welding process of the USW of ABS made with a 1.7 s welding time can be divided into five phases based on the amplitude and horn displacement change: weld initiation (Phase I), horn retraction (Phase II), melt-and-flow equilibrium (Phase III), horn indentation and squeeze out (Phase IV) and weld solidification (Phase V). Obvious pores emerged during Phase IV, owing to the thermal decomposition of the ABS. This study yielded a fundamental understanding of the USW of ABS and provides a theoretical basis and technological support for further application and promotion of other ultrasonically welded thermoplastic composites.
ABSTRACT
Peripheral nerve defect are common clinical problem caused by trauma or other diseases, often leading to the loss of sensory and motor function in patients. Autologous nerve transplantation has been the gold standard for repairing peripheral nerve defects, but its clinical application is limited due to insufficient donor tissue. In recent years, the application of tissue engineering methods to synthesize nerve conduits for treating peripheral nerve defect has become a current research focus. This study introduces a novel approach for treating peripheral nerve defects using a tissue-engineered PLCL/SF/NGF@TA-PPy-RGD conduit. The conduit was fabricated by combining electrospun PLCL/SF with an NGF-loaded conductive TA-PPy-RGD gel. The gel, synthesized from RGD-modified tannic acid (TA) and polypyrrole (PPy), provides growth anchor points for nerve cells. In vitro results showed that this hybrid conduit could enhance PC12 cell proliferation, migration, and reduce apoptosis under oxidative stress. Furthermore, the conduit activated the PI3K/AKT signalling pathway in PC12 cells. In a rat model of sciatic nerve defect, the PLCL/SF/NGF@TA-PPy-RGD conduit significantly improved motor function, gastrocnemius muscle function, and myelin sheath axon thickness, comparable to autologous nerve transplantation. It also promoted angiogenesis around the nerve defect. This study suggests that PLCL/SF/NGF@TA-PPy-RGD conduits provide a conducive environment for nerve regeneration, offering a new strategy for peripheral nerve defect treatment, this study provided theoretical basis and new strategies for the research and treatment of peripheral nerve defect.
Subject(s)
Hydrogels , Nerve Growth Factor , Nerve Regeneration , Oligopeptides , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-akt , Sciatic Nerve , Signal Transduction , Animals , Nerve Regeneration/drug effects , Rats , Proto-Oncogene Proteins c-akt/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Signal Transduction/drug effects , PC12 Cells , Sciatic Nerve/drug effects , Sciatic Nerve/injuries , Oligopeptides/pharmacology , Oligopeptides/chemistry , Hydrogels/chemistry , Nerve Growth Factor/pharmacology , Nerve Growth Factor/metabolism , Rats, Sprague-Dawley , Male , Cell Proliferation/drug effects , Apoptosis/drug effects , Tissue Scaffolds/chemistry , Tissue Engineering/methods , Polymers/chemistryABSTRACT
Miniaturized reconstructive spectrometers play a pivotal role in on-chip and portable devices, offering high-resolution spectral measurement through precalibrated spectral responses and AI-driven reconstruction. However, two key challenges persist for practical applications: artificial intervention in algorithm parameters and compatibility with complementary metal-oxide-semiconductor (CMOS) manufacturing. We present a cutting-edge miniaturized reconstructive spectrometer that incorporates a self-adaptive algorithm referenced with Fabry-Perot resonators, delivering precise spectral tests across the visible range. The spectrometers are fabricated with CMOS technology at the wafer scale, achieving a resolution of ~2.5 nm, an average wavelength deviation of ~0.27 nm, and a resolution-to-bandwidth ratio of ~0.46%. Our approach provides a path toward versatile and robust reconstructive miniaturized spectrometers and facilitates their commercialization.
ABSTRACT
Hydrogel-based iontronics is emerging as a promising frontier in healthcare and human-machine interfacing (HMI), offering excellent compatibility with biological systems in terms of electrical, chemical, and mechanical properties. However, conventional hydrogel systems have limitations in dynamically regulating their electrical and optical properties, which restricts their use in adaptive electronics and responsive interfaces. In this study, we present a new hydrogel system with UV photochemistry-induced reversible conductivity, enabling reversible changes in conductivity. Unlike typical photo-responsive hydrogels that revert to their original states upon removal of the light source, the new hydrogel can maintain its activated states without continuous light exposure, facilitating practical applications. By leveraging the photobase triphenylmethane leucohydroxide and photoacid n-nitrobenzaldehyde, we achieve a significant increase in photo-induced conductivity compared to existing photo-ionic hydrogels. Combining the effective photo-induced conductivity and the accompanied photochromatic effect, we demonstrate a full hydrogel-based stylus pad capable of tracking motion and strokes, and a soft calculator keypad with programmable conductivity and imprinted patterns. These advancements underscore the importance of actively controlling localized conductivity and processing light inputs in hydrogels, exhibiting their potential for diverse applications in bioelectronics and HMI.
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Objective: To evaluate the effects of high-intensity interval training (HIIT) on glycolipid metabolism among type 2 diabetes patients. Methods: HIIT is consistent with an exercise program (65%-90%VO2max or 75%-95% HRmax; exercise cycle≥2 weeks; frequency ≥ 2 times/week). A meta-analysis was conducted utilizing the random effects model to synthesize the data. Results: A total of 22 RCT studies with 1034 diabetic patients were included. Compared to moderate-intensity aerobic exercise or conventional controls, HIIT yields noteworthy effects on FBG (MD: -0.55; 95% CI: -0.85- -0.25, Hedges' g =0.98), 2h-PG (MD: -0.36; 95% CI: -0.57- -0.14, Hedges' g =1.05), FINS (MD: -0.41; 95% CI: -0.79- -0.03, Hedges' g =1.07), HbA1c (MD: -0.60; 95% CI: -0.84- -0.36, Hedges' g =2.69), TC (MD: -0.58; 95% CI: -0.80- -0.36, Hedges' g =2.36), TG (MD: -0.50; 95% CI: -0.86- -0.14, Hedges' g =1.50), HDL (MD: 0.62; 95% CI: 0.29-0.95, Hedges' g =1.19) and LDL (MD: -0.31; 95% CI: -0.56- -0.08, Hedges' g =0.91), all of the above p<0.01. Conclusions: HIIT has been shown to improve glucose and lipid metabolism in patients with type 2 diabetes, especially in HbA1c, TC, TG, and HDL. For patients between the ages of 40 and 60 with less than 5 years of disease, exercise programs of moderate to longer duration or moderate to high intensity will produce more favorable results.
Subject(s)
Blood Glucose , Diabetes Mellitus, Type 2 , High-Intensity Interval Training , Lipid Metabolism , Humans , Diabetes Mellitus, Type 2/metabolism , Diabetes Mellitus, Type 2/therapy , Diabetes Mellitus, Type 2/blood , High-Intensity Interval Training/methods , Lipid Metabolism/physiology , Blood Glucose/metabolism , Exercise Therapy/methods , Exercise/physiologyABSTRACT
Global warming has created problems for human life, and it has been increasing for a few years. All the developing and developed countries are establishing policies to attain zero carbon status. This study extends the ongoing debate on carbon emissions. It examines the effect of natural resources and RE (Biofuel and other renewable sources) on greenhouse gas (CO2 emission and PM2.5) emissions while using data over 22 years (1999-2021) from G7 countries. In addition, this study has investigated the effect of carbon taxes, financial development, and environmental policies on carbon neutrality. The cross-sectional-ARDL, the Common correlated effect means group (CCEMG), and the Augmented mean group (AMG) cutting-edge model have been employed. Quantile regression has been employed for robustness. The study results demonstrate that biofuel and other renewable energy (RE) sources, carbon taxes, environmental policy, and eco-innovation decrease greenhouse gas emissions (CO2 emissions). Meanwhile, financial development, and natural resource dependence positively impact carbon neutrality. The robustness result also verifies the findings from CS-ARDL, AMG, and CCEMG methods. The empirical findings are used to infer policy implications for G7 economies.
ABSTRACT
Entomopathogenic nematodes (EPNs) exhibit a bending-elastic instability, or kink, before becoming airborne, a feature hypothesized but not proven to enhance jumping performance. Here, we provide the evidence that this kink is crucial for improving launch performance. We demonstrate that EPNs actively modulate their aspect ratio, forming a liquid-latched closed loop over a slow timescale O (1 s), then rapidly open it O (10 µs), achieving heights of 20 body lengths (BL) and generating â¼ 10 4 W/Kg of power. Using jumping nematodes, a bio-inspired Soft Jumping Model (SoftJM), and computational simulations, we explore the mechanisms and implications of this kink. EPNs control their takeoff direction by adjusting their head position and center of mass, a mechanism verified through phase maps of jump directions in simulations and SoftJM experiments. Our findings reveal that the reversible kink instability at the point of highest curvature on the ventral side enhances energy storage using the nematode's limited muscular force. We investigated the impact of aspect ratio on kink instability and jumping performance using SoftJM, and quantified EPN cuticle stiffness with AFM, comparing it with C. elegans . This led to a stiffness-modified SoftJM design with a carbon fiber backbone, achieving jumps of â¼25 BL. Our study reveals how harnessing kink instabilities, a typical failure mode, enables bidirectional jumps in soft robots on complex substrates like sand, offering a novel approach for designing limbless robots for controlled jumping, locomotion, and even planetary exploration.
ABSTRACT
The development of smart hydrogels capable of actively controlling ion conductivity is of paramount importance for iontronics. Most current work in this field focuses on enhancing the hydrogels' ion conductivity. Few successes have been seen in achieving spatial regulation of ion flow through external control. Among various controls, light gives the best spatial and temporal resolution for practical iontronic applications. However, developing hydrogels that can generate drastic ion concentration change upon photoirradiation for tunable conductivity is challenging. Very few molecules can enable photoion generation, and most of them are hydrophobic and low quantum yield. Here, we present an optoionic hydrogel that uses triphenylmethane leuconitrile (TPMLN) for ultraviolet-regulated ion conductivity. Through postpolymerization TPMLN synthesizing, we can incorporate high concentration of the hydrophobic TPMLN in hydrogels without compromising the hydrogel's mechanical integrity. Upon light irradiation, the hydrogel's local conductivity can change an unprecedented 10-fold. We also demonstrated soft optoionic devices that are capable of logic processing and photo imaging.
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The present study compared the differences in effectiveness and safety between segmentectomy (ST) and wedge resection (WR) in patients with operable non-small cell lung cancer (NSCLC). The PubMed, EMBASE, Cochrane Library and Web of Science databases were searched for papers published from inception until July 2023. The inclusion criteria were based on the population, intervention, comparator, outcomes and study designs. ROBINS-I was selected to assess the risk of bias and quality of evidence in the included non-randomised studies. Appropriate effect sizes were selected, and subgroup analyses, heterogeneity tests, sensitivity analyses and publication bias were applied. A total of 18 retrospective studies were included, involving 19,381 patients with operable NSCLC. The 5-year overall survival rate [hazard ratio (HR), 0.19; 95% confidence interval (CI), 0.04, 0.34; P=0.014; I2=76.3%], lung cancer-specific survival rate (HR, 0.3; 95% CI, 0.21, 0.38; P<0.01; I2=13.8%) and metastasis rate [odds ratio (OR), 1.56; 95% CI, 1.03, 2.38; P=0.037] in patients with operable NSCLC treated with WR were worse than those in patients treated with ST. The incidence of postoperative complications (OR, 0.44; 95% CI, 0.23, 0.82) in the WR group was lower than in the ST treatment group. There was no difference in postoperative recurrence (OR, 2.15; 95% CI, 0.97, 4.74; P=0.058) and mortality (risk difference, 0.04; 95% CI, -0.03, 0.11; P=0.287) between groups. Based on current evidence, patients with NSCLC treated with ST surgery have better postoperative survival but more complications than those patients treated with WT, while the effect of WR and ST on the recurrence rate and distant metastasis rate remains controversial.
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Clear cell renal cell carcinoma (ccRCC) is the most common form of RCC. It is characterized by resistance to traditional radiotherapy and chemotherapy, as well as an unfavorable clinical prognosis. Although TYMP is implicated in the advancement of tumor progression, the role of TYMP in ccRCC is still not understood. Heightened TYMP expression was identified in ccRCC through database mining and confirmed in RCC cell lines. Indeed, TYMP knockdown impacted RCC cell proliferation, migration, and invasion in vitro. TYMP showed a positive correlation with clinicopathological parameters (histological grade, pathological stage). Moreover, patients with high TYMP expression were indicative of poor prognosis in TCGA-ccRCC and external cohorts. The results of single-cell analysis showed that the distribution of TYMP was predominantly observed in monocytes and macrophages. Furthermore, there is a significant association between TYMP and immune status. Methylation analysis further elucidated the relationship between TYMP expression and multiple methylation sites. Drug sensitivity analysis unveiled potential pharmaceutical options. Additionally, mutation analyses identified an association between TYMP and the ccRCC driver genes like BAP1 and ROS1. In summary, TYMP may serve as a reliable prognostic indicator for ccRCC.
Subject(s)
Biomarkers, Tumor , Carcinoma, Renal Cell , Kidney Neoplasms , Humans , Carcinoma, Renal Cell/genetics , Carcinoma, Renal Cell/diagnosis , Kidney Neoplasms/genetics , Kidney Neoplasms/pathology , Kidney Neoplasms/mortality , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Prognosis , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Male , Cohort Studies , Female , Cell Proliferation , DNA Methylation , Cell Movement , Middle AgedABSTRACT
This review article focuses on the recent printing technological progress in healthcare, underscoring the significant potential of implantable devices across diverse applications. Printing technologies have widespread use in developing health monitoring devices, diagnostic systems, and surgical devices. Recent years have witnessed remarkable progress in fabricating low-profile implantable devices, driven by advancements in printing technologies and nanomaterials. The importance of implantable biosensors and bioelectronics is highlighted, specifically exploring printing tools using bio-printable inks for practical applications, including a detailed examination of fabrication processes and essential parameters. This review also justifies the need for mechanical and electrical compatibility between bioelectronics and biological tissues. In addition to technological aspects, this article delves into the importance of appropriate packaging methods to enhance implantable devices' performance, compatibility, and longevity, which are made possible by integrating cutting-edge printing technology. Collectively, we aim to shed light on the holistic landscape of implantable biosensors and bioelectronics, showcasing their evolving role in advancing healthcare through innovative printing technologies.
Subject(s)
Biosensing Techniques , Prostheses and Implants , Biosensing Techniques/instrumentation , Humans , Electronics/instrumentation , Printing, Three-Dimensional , Equipment Design , Nanostructures/chemistry , Delivery of Health Care/trendsABSTRACT
Water scarcity has driven the demand for water production from unconventional sources and the reuse of industrial wastewater. Pressure-driven membranes, notably thin-film composite (TFC) membranes, stand as energy-efficient alternatives to the water scarcity challenge and various wastewater treatments. While pressure drives solvent movement, it concurrently triggers membrane compaction and flux deterioration. This necessitates a profound comprehension of the intricate interplay among compressive modulus, structural properties, and transport efficacy amid the compaction process. In this study, we present an all-encompassing compaction model for TFC membranes, applying authentic structural and mechanical variables, achieved by coupling viscoelasticity with Monte Carlo flux calculations based on the resistance-in-series model. Through validation against experimental data for multiple commercial membranes, we evaluated the influence of diverse physical parameters. We find that support polymers with a higher compressive modulus (lower compliance), supports with higher densities of "finger-like" pores, and "sponge-like" pores with optimum void fractions will be preferred to mitigate compaction. More importantly, we uncover a trade-off correlation between steady-state permeability and the modulus for identical support polymers displaying varying porosities. This model holds the potential as a valuable guide in shaping the design and optimization for further TFC applications and extending its utility to biological scaffolds and hydrogels with thin-film coatings in tissue engineering.
Subject(s)
Membranes, Artificial , Porosity , Permeability , Polymers/chemistryABSTRACT
Releasing pre-strained two-dimensional nanomembranes to assemble on-chip three-dimensional devices is crucial for upcoming advanced electronic and optoelectronic applications. However, the release process is affected by many unclear factors, hindering the transition from laboratory to industrial applications. Here, we propose a quasistatic multilevel finite element modeling to assemble three-dimensional structures from two-dimensional nanomembranes and offer verification results by various bilayer nanomembranes. Take Si/Cr nanomembrane as an example, we confirm that the three-dimensional structural formation is governed by both the minimum energy state and the geometric constraints imposed by the edges of the sacrificial layer. Large-scale, high-yield fabrication of three-dimensional structures is achieved, and two distinct three-dimensional structures are assembled from the same precursor. Six types of three-dimensional Si/Cr photodetectors are then prepared to resolve the incident angle of light with a deep neural network model, opening up possibilities for the design and manufacturing methods of More-than-Moore-era devices.
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Large language models are enabling rapid progress in robotic verbal communication, but nonverbal communication is not keeping pace. Physical humanoid robots struggle to express and communicate using facial movement, relying primarily on voice. The challenge is twofold: First, the actuation of an expressively versatile robotic face is mechanically challenging. A second challenge is knowing what expression to generate so that the robot appears natural, timely, and genuine. Here, we propose that both barriers can be alleviated by training a robot to anticipate future facial expressions and execute them simultaneously with a human. Whereas delayed facial mimicry looks disingenuous, facial coexpression feels more genuine because it requires correct inference of the human's emotional state for timely execution. We found that a robot can learn to predict a forthcoming smile about 839 milliseconds before the human smiles and, using a learned inverse kinematic facial self-model, coexpress the smile simultaneously with the human. We demonstrated this ability using a robot face comprising 26 degrees of freedom. We believe that the ability to coexpress simultaneous facial expressions could improve human-robot interaction.
Subject(s)
Robotics , Humans , Movement , Learning , BiomimeticsABSTRACT
Glycolysis exerts a key role in the metabolic reprogramming of cancer. Specific long non-coding RNAs (lncRNAs) have been identified to exhibit oncogenic glycolysis regulation. Nevertheless, the precise mechanisms by which glycolysis-related lncRNAs control hepatocellular carcinoma (HCC) are still unknown. We profiled and analyzed glycolysis-associated lncRNA signatures using HCC specimens from The Cancer Genome Atlas (TCGA) dataset. Considerable upregulation of the glycolysis-related lncRNA SLC2A1-DT was noted in HCC tissues; this upregulation was strongly linked with advanced tumor stage and poor prognosis. Cell culture and animal-related studies indicated that knockdown or overexpression of SLC2A1-DT obviously restrained or promoted glycolysis, propagation, and metastasis in HCC cells. Mechanistically, SLC2A1-DT enhanced the interaction of protein between ß-catenin and YWHAZ, suppressing the binding between ß-catenin and ß-TrCP, an E3 ubiquitin ligase. Thereby, SLC2A1-DT impeded the ß-TrCP-dependent ubiquitination and ß-catenin degradation. The upregulated ß-catenin activated the transcription of c-Myc, which then increased the transcription of glycolytic genes including SLC2A1, LDHA, and HK2. Additionally, we revealed that c-Myc transcriptionally induced the expression of methyltransferase 3 (METTL3), which increased N6-methyladenosine (m6A) modification and stability of SLC2A1-DT in a YTHDF1 dependent manner. Collectively, we show that the lncRNA SLC2A1-DT promotes glycolysis and HCC tumorigenesis by a m6A modification-mediated positive feedback mechanism with glycolytic regulator c-Myc and suggested as an innovative treatment option and indicator for HCC.
Subject(s)
Adenine/analogs & derivatives , Carcinoma, Hepatocellular , Liver Neoplasms , RNA, Long Noncoding , Animals , Carcinoma, Hepatocellular/metabolism , Liver Neoplasms/metabolism , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , beta Catenin/genetics , beta Catenin/metabolism , Feedback , beta-Transducin Repeat-Containing Proteins/metabolism , Cell Line, Tumor , Carcinogenesis/genetics , Cell Transformation, Neoplastic/genetics , Glycolysis/genetics , Gene Expression Regulation, Neoplastic/genetics , Cell Proliferation/geneticsABSTRACT
OBJECTIVES: To describe the epidemiological characteristics of pediatric sepsis in Southwest China PICUs. DESIGN: A prospective, multicenter, and observational study. SETTING: Twelve PICUs in Southwest China. PATIENTS: The patients admitted to the PICU from April 1, 2022, to March 31, 2023. The age ranged from 28 days to 18 years. All patients met the criteria of severe sepsis or septic shock. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 31 PICUs invited to participate, 12 PICUs (capacity of 292 beds) enrolled patients in the study. During the study period, 11,238 children were admitted to the participating PICUs, 367 (3.3%) of whom met the diagnosis of severe sepsis or septic shock. The most prevalent sites of infection were the respiratory system (55%) and the digestive system (15%). The primary treatments administered to these patients included antibiotics (100%), albumin (61.3%), invasive mechanical ventilation (58.7%), glucocorticoids (55.6%), blood products (51%), gammaglobulin (51%), and vasoactive medications (46.6%). Sepsis-related mortality in the PICU was 11.2% (41/367). Nearly half of the sepsis deaths occurred within the first 3 days of PICU admission (22/41, 53.7%). The mortality rate of septic shock (32/167, 19.2%) was significantly higher than that of severe sepsis (9/200, 4.5%; p < 0.001). The outcomes of a multivariate logistic regression analysis suggested that a higher pediatric Sequential Organ Failure Assessment score, and the use of invasive mechanical ventilation and vasoactive medications were independently associated with PICU mortality in children with sepsis. CONCLUSIONS: This report updates the epidemiological data of pediatric sepsis in PICUs in Southwest China. Sepsis is still a life-threatening disease in children.
Subject(s)
Intensive Care Units, Pediatric , Sepsis , Humans , Prospective Studies , Child, Preschool , China/epidemiology , Child , Infant , Male , Female , Adolescent , Intensive Care Units, Pediatric/statistics & numerical data , Sepsis/epidemiology , Infant, Newborn , Hospital Mortality , Shock, Septic/epidemiologyABSTRACT
We applied solid- and solution-state nuclear magnetic resonance spectroscopy to examine the structure of multidomain peptides composed of self-assembling ß-sheet domains linked to bioactive domains. Bioactive domains can be selected to stimulate specific biological responses (e.g., via receptor binding), while the ß-sheets provide the desirable nanoscale properties. Although previous work has established the efficacy of multidomain peptides, molecular-level characterization is lacking. The bioactive domains are intended to remain solvent-accessible without being incorporated into the ß-sheet structure. We tested for three possible anticipated molecular-level consequences of introducing bioactive domains to ß-sheet-forming peptides: (1) the bioactive domain has no effect on the self-assembling peptide structure; (2) the bioactive domain is incorporated into the ß-sheet nanofiber; and (3) the bioactive domain interferes with self-assembly such that nanofibers are not formed. The peptides involved in this study incorporated self-assembling domains based on the (SL)6 motif and bioactive domains including a VEGF-A mimic (QK), an IGF-mimic (IGF-1c), and a de novo SARS-CoV-2 binding peptide (SBP3). We observed all three of the anticipated outcomes from our examination of peptides, illustrating the unintended structural effects that could adversely affect the desired biofunctionality and biomaterial properties of the resulting peptide hydrogel. This work is the first attempt to evaluate the structural effects of incorporating bioactive domains into a set of peptides unified by a similar self-assembling peptide domain. These structural insights reveal unmet challenges in the design of highly tunable bioactive self-assembling peptide hydrogels.
Subject(s)
Nanofibers , Peptides , Protein Conformation, beta-Strand , Peptides/chemistry , Nanofibers/chemistry , Hydrogels/chemistry , Biocompatible MaterialsABSTRACT
BACKGROUND: Ginsenoside Rg3 (G-Rg3), extracted from Panax notoginseng, possesses hepatoprotective properties. Hepatic stellate cells (HSCs) activation is responsible for liver fibrosis. Recent studies have reported the suppressive effects of G-Rg3 on HSC activation and proliferation. Ferroptosis is a novel iron regulated cell death. ACSL4, a key indicator of ferroptosis, is commonly methylated in various diseases. PURPOSE: However, the role of ACSL4 methylation-mediated HSC ferroptosis in G-Rg3 inhibition of hepatic fibrosis needs to be explored. METHODS: Effects of G-Rg3 on inhibiting fibrosis were evaluated in vivo and in vitro. The impact of G-Rg3 on HSC ferroptosis was assessed in vitro. Furthermore, the expression of ACSL4, ACSL4 methylation and microRNA-6945-3p (miR-6945-3p) levels were determined. RESULTS: G-Rg3 significantly alleviated CCl4-induced liver fibrosis, accompanied by collagen downregulation. In vitro, G-Rg3 contributed to HSC inactivation, leading to decreased collagen production. G-Rg3 induced HSC ferroptosis, characterized by increased iron accumulation, depletion of glutathione, malondialdehyde levels, and generation of lipid reactive oxygen species. Moreover, G-Rg3 promoted ACSL4 demethylation and restored its expression. Notably, DNMT3B counteracted the effect of G-Rg3-mediated inhibition of ACSL4 methylation and was targeted by miR-6945-3p. Further investigations revealed that G-Rg3 suppressed ACSL4 methylation through miR-6945-3p-mediated DNMT3B inhibition. Consistent with this, miR-6945-3p inhibition reversed G-Rg3-induced ACSL4 expression and HSC ferroptosis. CONCLUSION: G-Rg3 inhibits ACSL4 methylation by miR-6945-3p-mediated DNMT3B inhibition, thereby promoting HSC ferroptosis and mitigating liver fibrosis.