Mitophagy and its regulatory mechanisms in the biological effects of nanomaterials

Mitophagy is a selective cellular process critical for the removal of damaged mitochondria. It is essential in regulating mitochondrial number, ensuring mitochondrial functionality, and maintaining cellular equilibrium, ultimately influencing cell destiny. Numerous pathologies, such as neurodegenerative diseases, cardiovascular disorders, cancers, and various other conditions, are associated with mitochondrial dysfunctions. Thus, a detailed exploration of the regulatory mechanisms of mitophagy is pivotal for enhancing our understanding and for the discovery of novel preventive and therapeutic options for these diseases. Nanomaterials have become integral in biomedicine and various other sectors, offering advanced solutions for medical uses including biological imaging, drug delivery, and disease diagnostics and therapy. Mitophagy is vital in managing the cellular effects elicited by nanomaterials. This review provides a comprehensive analysis of the molecular mechanisms underpinning mitophagy, underscoring its significant influence on the biological responses of cells to nanomaterials. Nanoparticles can initiate mitophagy via various pathways, among which the PINK1-Parkin pathway is critical for cellular defense against nanomaterial-induced damage by promoting mitophagy. The role of mitophagy in biological effects was induced by nanomaterials, which are associated with alterations in Ca2+ levels, the production of reactive oxygen species, endoplasmic reticulum stress, and lysosomal damage.

Silver nanoparticles induced synaptic degeneration via Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells

Silver nanoparticles (AgNPs) have been widely used in biomedicine and cosmetics, increasing their potential risks in neurotoxicity. But the involved molecular mechanism remains unclear. This study aims to explore molecular events related to AgNPs-induced neuronal damage by RNA-seq, and elucidate the role of Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells synaptic degeneration induced by AgNPs. This study found that cell viabilities were decreased by AgNPs in a dose/time-dependent manner. AgNPs also increased protein expression of PINK1, Parkin, synaptophysin, and inhibited PGC-1α, MAP2 and APP protein expression, indicating AgNPs-induced synaptic degeneration involved in disturbance of mitophagy and mitochondrial biogenesis in HT22 cells. Moreover, inhibition of AgNPs-induced Ca2+/CaMKII activation and Drp1/ROS rescued mitophagy disturbance and synaptic degeneration in HT22 cells by reserving aforementioned protein express changes except for PGC-1α and APP protein. Thus, AgNPs-induced synaptic degeneration was mediated by Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells, and mitophagy is the sensitive to the mechanism. Our study will provide in-depth molecular mechanism data for neurotoxic evaluation and biomedical application of AgNPs.

Oxidative stress-activated Nrf2 remitted polystyrene nanoplastic-induced mitochondrial damage and inflammatory response in HepG2 cells

Generated from plastics, microplastics (MPs) and nanoplastics (NPs) are difficult to completely degrade in the natural environment, which can accumulate in almost all lives. Liver is one of the main target organs. In this study, HepG2 and L02 cells were exposed to 0-50 μg/mL polystyrene (PS)-NPs to investigate the mechanism of mitochondrial damage and inflammation. The results showed mitochondria damage and inflammatory caused by NPs, and it can be inhibited by N-acetyl-L-cysteine (NAC). In addition, reactive oxygen species (ROS) activated nuclear factor erythroid-derived factor 2-related factor (Nrf2) pathway. Nrf2 siRNA exacerbated the injury, suggesting Nrf2 plays a protective role. Moreover, p62 siRNA increased ROS and mitochondrial damage by inhibiting Nrf2, but didn't affect the inflammation. In conclusion, Nrf2 was activated by ROS and played a protective role in PS-NPs-mediated hepatotoxicity. This study supplemented the data of liver injury caused by PS-NPs, providing a basis for the safe disposal of plastics.

Comparative oxidative damages induced by silver nanoparticles with different sizes and coatings in Caenorhabditis elegans

Silver nanoparticles (AgNPs) are widely used in many commercial and medical products. Serious concerns are paid on their adverse potentials to the environment and human health. In this study, toxic effects and oxidative stress induced by AgNPs with different sizes and coatings (20 nm AgNPs, 20 nm polyvinylpyrrolidone (PVP) -AgNPs and 50 nm AgNPs) in Caenorhabditis elegans (C. elegans) were investigated. The toxic effects including the shortened lifespan and decreased frequency of head thrashes and body bends of C. elegans were induced in a dose-dependent manner by AgNPs. The reactive oxygen species (ROS) production and the oxidative stress-related indicators including malondialdehyde (MDA) and glutathione (GSH) in nematodes were changed after exposure to three kinds of AgNPs. These effects were the most obvious in a 20 nm PVP-AgNPs exposure group. AgNPs could also induce the expression of genes related to oxidative stress in nematodes. In addition, the up-regulation of mtl-1 and mtl-2 in nematodes might reduce the oxidative damage caused by AgNPs, by using transgenic strains CF2222 and CL2120 nematodes. Metallothionein (MT), an antioxidant, could relieve the oxidative damage caused by AgNPs. These results suggested that 20 nm PVP-AgNPs with a smaller particle size and better dispersion have stronger toxic effects and the oxidative damage to nematodes. Mtl-1 and mtl-2 might be involved in alleviating the oxidative damage caused by AgNPs. Our findings provide clues for the safety evaluation and mechanism information of metal nanoparticles.

ROS-Drp1-mediated mitochondria fission contributes to hippocampal HT22 cell apoptosis induced by silver nanoparticles

Silver nanoparticles (AgNPs) have widely used in industrial and medical applications for their excellent antibacterial activities. AgNPs can penetrate into the brain and cause neuronal death, but limited evidence focused on toxic effects and mechanic study in hippocampal neuron. This study aimed to investigate the molecular mechanisms of mitochondrial damage and apoptosis in mouse hippocampal HT22 cells and further to explore role of reactive oxygen species (ROS) and GTPase dynamin-related protein 1 (Drp1) in AgNPs-induced neurotoxicity. Our results showed that acute exposure to AgNPs at low doses (2-8 μg/mL) increased ROS generation, decreased mitochondrial membrane potential (MMP) and ATP synthesis in HT22 cells. In addition, AgNPs promoted mitochondrial fragmentation and mitochondria-dependent apoptosis via excessive mitochondrial fission/fusion by 8 μg/mL AgNPs treatment for 24 h. The mechanism was involved in increased protein expression of Drp1, mitochondrial fission protein 1 (Fis1), mitofusin 1/2 (Mfn1/2) and inhibited optic atrophy 1 (OPA1), and mainly mediated by phosphorylation of Drp1 Ser616. The AgNPs-induced mitochondrial impairment and apoptosis was mainly due to their particle-specific effect rather than silver ions release. Furthermore Drp1-mediated mitochondrial fission contributed to mitochondria-dependent apoptosis induced by AgNPs, all aforementioned changes were significantly rescued by N-acetyl-l-cysteine (NAC) and Mdivi-1 except for OPA1 protein expression. Hence, our results provide a novel neurotoxic mechanism to AgNPs-induced neurotoxicity and revealed that the mechanism of mitochondria-dependent apoptosis in HT22 cells was mediated by excessive activation of ROS-Drp1-mitochondrial fission axis. These findings can deepen current evidences on neurotoxicological evaluation of AgNPs and aid in guiding their proper applications in different areas, especially in biomedical use.

ROS and DRP1 interactions accelerate the mitochondrial injury induced by polystyrene nanoplastics in human liver HepG2 cells

Microplastics have become a serious environmental pollutant and subsequently have harmful effects on human health. Thus, the impacts of microplastics on human cells need to be explored. In the present study, the cytotoxic effects at the subcellular-organelle levels to polystyrene nanoplastics (PS-NPs, diameter 21.5 ± 2.7 nm) were investigated in the human hepatocellular carcinoma (HepG2) cell line. The cell viability exposed to PS-NPs at the concentrations of 6.25, 12.5, 25 and 50 μg/mL for 24 h diminished in a concentration-dependent manner. The PS-NPs treatment induced mitochondrial injuries, including morphological changes, decreased adenosine triphosphate (ATP) production and the loss of mitochondrial membrane potentials (MMP). The PS-NPs treatment could further spark cell apoptosis by upregulating caspase 3, caspase 9, cytochrome c, and Bcl-2 associated X protein (Bax)/B-cell lymphoma-2 (Bcl-2) in HepG2 cells, which is related to the mitochondrial dysfunction. PS-NPs exposure stimulated the excessive cellular reactive oxygen species (ROS) production and also induced mitochondrial fission by upregulating dynamin-related protein 1 (DRP1) and P-DRP1, but downregulating optic atrophy protein 1 (OPA1) and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α) expression levels. The above effects on mitochondria damage induced by PS-NPs were reversed by the pretreatment of N-acetylcysteine (NAC), mitochondrial division inhibitor 1 (Mdivi-1) and DRP1 siRNA. The results suggested that the interaction between ROS and DRP1-dependent mitochondrial division could promote mitochondrial lesions and mitochondria-related apoptosis caused by PS-NPs. These findings on molecular mechanisms provide a theoretical basis for preventing the hazards caused by microplastics to human health.

Effect of Avian Influenza Virus subtype H9N2 on the expression of complement-associated genes in chicken erythrocytes

The H9N2 subtype avian influenza virus can infect both chickens and humans. Previous studies have reported a role for erythrocytes in immunity. However, the role of H9N2 against chicken erythrocytes and the presence of complement-related genes in erythrocytes has not been studied. This research investigated the effect of H9N2 on complement-associated gene expression in chicken erythrocytes. The expression of complement-associated genes (C1s, C1q, C2, C3, C3ar1, C4, C4a, C5, C5ar1, C7, CD93 and CFD) was detected by reverse transcription-polymerase chain reaction (RT-PCR). Quantitative Real-Time PCR (qRT-PCR) was used to analyse the differential expression of complement-associated genes in chicken erythrocytes at 0 h, 2 h, 6 h and 10 h after the interaction between H9N2 virus and chicken erythrocytes in vitro and 3, 7 and 14 d after H9N2 virus nasal infection of chicks. Expression levels of C1q, C4, C1s, C2, C3, C5, C7 and CD93 were significantly up-regulated at 2 h and significantly down-regulated at 10 h. Gene expression levels of C1q, C3ar1, C4a, CFD and C5ar1 were seen to be different at each time point. The expression levels of C1q, C4, C1s, C2, C3, C5, C7, CFD, C3ar1, C4a and C5ar1 were significantly up-regulated at 7 d and the gene expression of levels of C3, CD93 and C5ar1 were seen to be different at each time point. The results confirmed that all the complement-associated genes were expressed in chicken erythrocytes and showed the H9N2 virus interaction with chicken erythrocytes and subsequent regulation of chicken erythrocyte complement-associated genes expression. This study reported, for the first time, the relationship between H9N2 and complement system of chicken erythrocytes, which will provide a foundation for further research into the prevention and control of H9N2 infection.

Recombinant human metallothionein-III alleviates oxidative damage induced by copper and cadmium in Caenorhabditis elegans

Recombinant human metallothionein III (rh-MT-III) is a genetically engineered product produced by Escherichia coli fermentation technology. Its molecules contain abundant reducing sulfhydryl groups, which possess the ability to bind heavy metal ions. The present study was to evaluate the binding effects of rh-MT-III against copper and cadmium in vitro and to investigate the antioxidant activity of rh-MT-III using Caenorhabditis elegans in vivo. For in vitro experiments, the binding rates of copper and cadmium were 91.4% and 97.3% for rh-MT-III at a dosage of 200 μg/mL at 10 h, respectively. For in vivo assays, the oxidative stress induced by copper (CuSO₄ , 10 μg/mL) and cadmium (CdCl₂ , 10 μg/mL) was significantly reduced after 72 h of exposure to different doses of rh-MT-III (5-500 μg/mL), indicated by restoring locomotion behavior and growth, and reducing malondialdehyde and reactive oxygen species levels in C. elegans. Moreover, rh-MT-III decreased the deposition of lipofuscin and fat content, which could delay the progression of aging. In addition, rh-MT-III (500 μg/mL) promoted the up-regulation of Mtl-1 and Mtl-2 gene expression in C. elegans, which could enhance the resistance to oxidative stress by increasing the enzymatic activity of antioxidant defense system and scavenging free radicals. The results indicated that supplemental rh-MT-III could effectively protect C. elegans from heavy metal stress, providing an experimental basis for the future application and development of rh-MT-III.

Invasive fungal infection is associated with antibiotic exposure in preterm infants: a multi-centre prospective case-control study

BACKGROUND

Previous antibiotic exposure is an important risk factor for invasive fungal infection (IFI). Antibiotic overexposure is common in lower-income countries; however, multi-centre studies concerning IFI in relation to antibiotic exposure are scarce.

AIM

This prospective, multi-centre matched case-control study explored the correlation of IFI and antibiotic exposure in very preterm infants or very-low-birthweight infants admitted to 23 tertiary hospitals in China between 2018 and 2021.

METHODS

Using a 1:2 matched design for gestational age, birth weight and early-onset sepsis (yes/no), the risk factors between infants diagnosed with IFI and infection-free controls were compared. The antibiotic use rate (AUR) was calculated using calendar days of antibiotic therapy in the 4 weeks preceding IFI onset divided by onset day of IFI.

FINDINGS

In total, 6368 infants were included in the study, of which 90 (1.4%) were diagnosed with IFI. Median AUR, length of antibiotic therapy (LOT) and days of antibiotic therapy (DOT) within the 4 weeks preceding IFI onset were 0.90, 18 days and 30 days, respectively. Multi-variate analysis showed that a 10% increase in AUR, each additional day of DOT and LOT, and each additional day of third-generation cephalosporins and carbapenems were notably associated with IFI.

CONCLUSION

Prolonged antibiotic therapy is common before the onset of IFI, and is an important risk factor, especially the use of third-generation cephalosporins and carbapenems. Antibiotic stewardship should be urgently developed and promoted for preterm infants in order to reduce IFI in lower-income countries such as China.

Adaptive regulations of Nrf2 alleviates silver nanoparticles-induced oxidative stress-related liver cells injury

Silver nanoparticles (AgNPs) are widely used in various fields such as industry, agriculture, and medical care because of their excellent broad-spectrum antibacterial activity. However, their extensive use has raised concerns about their health risks. Liver is one of the main target organs for the accumulation and action of AgNPs. Therefore, evaluating the toxic effects of AgNPs on liver cells and its mechanisms of action is crucial for the safe application of AgNPs. In the study, polyvinylpyrrolidone (PVP)-coated AgNPs were characterized. The human hepatoma cell line (HepG2) and the normal hepatic cell line (L02) were exposed to different concentrations of AgNPs (20-160 μg/mL) and pretreated with the addition of N-acetylcysteine (NAC) or by Nrf2 siRNA transfection. NAC was able to inhibit the concentration-dependent increase in the level of apoptosis induced by AgNPs in HepG2 cells and L02 cells. Interestingly, HepG2 cells were more sensitive to AgNPs than L02 cells, and this may be related to the different ROS generation and responses to AgNPs by cancer cells and normal cells. In addition, NAC also alleviated the imbalance of antioxidant system and cell cycle arrest, which may be related to AgNPs-induced DNA damage and autophagy. The knockdown of nuclear factor erythroid-derived factor 2-related factor (Nrf2) found that AgNPs-induced ROS and apoptosis levels were further upregulated, but the cell cycle arrest was alleviated. On the whole, Nrf2 exerts a protective role in AgNPs-induced hepatotoxicity. This study complements the hepatotoxicity mechanisms of AgNPs and provides data for a future exploration of AgNPs-related anti-hepatocellular carcinoma drugs.

From Passive Signal Output to Intelligent Response: "On-Demand" Precise Imaging Controlled by Near-Infrared Light

"On-demand" accurate imaging of multiple intracellular miRNAs will significantly improve the detection reliability and accuracy. However, the "always-active" design of traditional multicomponent detection probes enables them to passively recognize and output signals as soon as they encounter targets, which will inevitably impair the detection accuracy and, inevitably, result in false-positive signals. To address this scientific problem, in this work, we developed a near-infrared (NIR) light-activated multicomponent detection intelligent nanoprobe for spatially and temporally controlled on-demand accurate imaging of multiple intracellular miRNAs. The proposed intelligent nanoprobe is composed of a rationally designed UV light-responsive triangular DNA nano sucker (TDS) and upconversion nanoparticles (UCNPs), named UCNPs@TDS (UTDS), which can enter cells autonomously through endocytosis and enable remote regulation of on-demand accurate imaging for multiple intracellular miRNAs using NIR light illumination at a chosen time and place. It is worth noting that the most important highlight of the UTDS we designed in this work is that it can resist nonspecific activation as well as effectively avoid false-positive signals and improve the accuracy of imaging of multiple intracellular miRNAs. Moreover, distinguishing different kinds of cell lines with different miRNA expressions levels can be also achieved through this NIR light-activated intelligent UTDS, showing feasible prospects in precise imaging and disease diagnosis.

[Treatment strategies and research progress of acute ilio-femoral deep vein thrombosis]

In the past,treatment of acute ilio-femoral deep vein thrombosis (IFDVT) was mainly based on anticoagulation alone,but 30%-50% of patients will develop post-thrombotic syndrome,causing a serious medical burden.Thrombus removal technology such as catheter-directed thrombolysis and percutaneous mechanical thrombectomy can effectively remove blood clots and compensate for the deficiencies of simple anticoagulation,which is expected to improve the prognosis of such disease,but the current evidence is insufficient,and other treatments such as filter implantation and compression therapy are also controversial.This article summarizes the treatment strategies and the latest progress of acute IFDVT,hoping to help the treatment of this type of disease.

The crosstalk between DRP1-dependent mitochondrial fission and oxidative stress triggers hepatocyte apoptosis induced by silver nanoparticles

Previous studies have revealed that the liver is the main target organ of deposition for engineered nanoparticles. The hepatotoxicity of silver nanoparticles (AgNPs), the widely used antimicrobial nanoparticles, has been of great interest. However, little is known about the regulatory mechanism of the mitochondria in AgNP-induced hepatotoxicity. In the present study, we found that AgNPs, rather than silver ions, induced mitochondrial dynamics disorders, oxidative stress, and mitochondria-dependent hepatocyte apoptosis in mice. Using human hepatocellular carcinoma (HepG2) cells, we confirmed that the interaction between dynamin-related protein 1 (DRP1)-dependent mitochondrial fission and oxidative stress promoted mitochondrial damage and mitochondria-dependent apoptosis induced by AgNPs, as determined by the elimination of DRP1 or addition of N-acetylcysteine (NAC). Interestingly, the crosstalk between DRP1-dependent mitochondrial fission and oxidative stress also activated mitophagy and autophagy flux blocking. Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1) gene silencing contributed to the aggravation of mitochondrial damage, oxidative stress, and apoptosis. These results revealed that the interplay between mitochondrial fission and oxidative stress induced mitophagy defects and triggered AgNP-induced mitochondria-dependent apoptosis in liver cells both in vivo and in vitro. Our findings provide a perspective for the mechanism of hepatotoxicity induced by exposure to metal NPs.

Anti-Fouling Magnetic Beads Combined with Signal Amplification Strategies for Ultra-Sensitive and Selective Electrochemiluminescence Detection of MicroRNAs in Complex Biological Media

Herein, an electrochemiluminescence (ECL) microRNA biosensor based on anti-fouling magnetic beads (MBs) and two signal amplification strategies was developed. The newly designed anti-fouling dendritic peptide was wrapped on the surfaces of MBs to make them resistant to nonspecific adsorption of biomolecules in complex biological samples so as to realize accurate and selective target recognition. One of the amplification strategies was achieved through nucleic acid cycle amplification based on the DNAzyme on the surfaces of MBs. Then, the output DNA generated by the nucleic acid cycle amplification program stimulated the hybrid chain reaction (HCR) process on the modified electrode surface to generate the other amplification of the ECL response. Titanium dioxide nanoneedles (TiO₂ NNs), as a co-reaction accelerator of the Ru(bpy)₂(cpaphen)²⁺ and tripropylamine (TPrA) system, were wrapped with the electrodeposited polyaniline (PANI) on the electrode surface to enhance the ECL intensity of Ru(bpy)₂(cpaphen)²⁺. The conducting polymer PANI can not only immobilize the TiO₂ NNs but also improve the conductivity of the modified electrodes. The biosensor exhibited ultra-high sensitivity and excellent selectivity toward the detection of miRNA 21, with a detection limit of 0.13 fM. More importantly, with the anti-fouling MBs as a unique separation tool, this ECL biosensor was capable of assaying targets in complex biological media such as serum and cell lysate.

The key role of autophagy in silver nanoparticle-induced BV2 cells inflammation and polarization

As the release of silver nanoparticles (AgNPs) in the environment continues to increase, great concerns have been raised about their potential toxicity to humans. It is urgent to assess the possible toxicity of AgNPs to the immune cells of the central nervous system due to the continuous accumulation of AgNPs in the brain. This study aimed to evaluate the neurotoxicity of AgNPs and the regulatory mechanism of autophagy in AgNPs-induced inflammation by using mouse microglia BV2 cell lines. AgNPs decreased the microglia cell activity in a concentration and time-dependent manner. The exposure of BV2 cells to AgNPs at a non-cytotoxic level of 5 μg/mL resulted in increase of pro-inflammatory cytokines and decrease of mRNA expression of anti-inflammatory cytokines. AgNPs exposure increased M1 markers of iNOS expression and decreased the expression of M2 markers of CD206 in a time-dependent manner. Meanwhile, the expression of inflammatory proteins IL-1β and NF-κB increased significantly. Additionally, AgNPs induced an increase in autophagosome and upregulation of LC3II, Beclin1, and p62 expression levels. Pretreatment by an autophagy inhibitor, 3-Methyladenine, caused more AgNPs-treated microglia to polarized into pro-inflammatory phenotypes. Inhibition of autophagy also increased the expression of inflammation-associated mRNA and proteins in BV2 cells. These results indicated that AgNPs could induce pro-inflammatory phenotypic polarization of microglia and the autophagy could play a key regulatory role in the pro-inflammatory phenotypic polarization of microglia induced by AgNPs.

Neurobehavior and neuron damage following prolonged exposure of silver nanoparticles with/without polyvinylpyrrolidone coating in Caenorhabditis elegans

Silver nanoparticles (AgNPs) have become widespread in the environment with increasing industrial applications. But the studies about their potential health risks are far from enough, especially in neurotoxic effects. This study aimed to investigate the neurotoxic effects of longer-term exposure (prolonged exposure for 48 h and chronic exposure for 6 days) of 20nm AgNPs with/without polyvinylpyrrolidone (PVP) coating at low concentrations (0.01-10 mg·L^-1 ) to Caenorhabditis elegans. The results suggested that exposure to AgNPs induced damage to nematode survival, with the longest and relative average life span reduced. Exposure to AgNPs caused neurotoxicity on locomotion behaviors (head thrashes, body bends, pharyngeal pumping frequency, and defecation interval) and sensory perception behaviors (chemotaxis assay and thermotaxis assay), as well as impaired dopaminergic, GABAergic, and cholinergic neurons, except for glutamatergic, based on the alters fluorescence intensity, in a dose- and time-dependent manner. Further investigations suggested that the low-dose AgNPs (0.01-0.1 mg·L^-1 ) exposure raises receptors of GABAergic and dopamine in C. elegans at the genetic level, whereas opposite results were observed at higher doses (1-10 mg·L^-1 ), which implied that AgNPs could cause neurotoxicity by impairing neurotransmitter delivery. The PVP-AgNPs could cause a higher fatality rate and neurotoxicity at the same dose. Notably, AgNPs did not cause any deleterious effect on nematodes at the lowest dose of 0.01 mg·L^-1 . In general, these results suggested that AgNPs possess the neurotoxic potential in C. elegans and provided useful information to understand the neurotoxicity of AgNPs, which would offer an inspiring perspective on the safe application.

Many Birds, One Stone: A Smart Nanodevice for Ratiometric Dual-Spectrum Assay of Intracellular MicroRNA and Multimodal Synergetic Cancer Therapy

The development of a theragnostic platform integrating precise diagnosis and effective treatment is significant but still extremely challenging. Herein, an integrated smart nanodevice composed of Au@Cu_2-xS@polydopamine nanoparticles (ACSPs) and fuel DNA-conjugated tetrahedral DNA nanostructures (fTDNs) was constructed, in which the ACSP nanoprobe played multiple key roles in antitumor therapy as well as in situ monitoring of microRNAs (miRNAs) in cancer cells. Regarding the analysis, the ACSP probe contained two optical properties: excellent surface-enhanced Raman scattering (SERS) enhancement and high fluorescence (FL) quenching performance. Employing the ACSPs as the high-efficiency detection substrate combined with the fTDN-assisted DNA walking nanomachines as the superior amplification strategy, a SERS-FL dual-spectrum biosensor was constructed, which achieved an ultralow background signal and excellent sensitivity with detection limits of 0.11 pM and 4.95 aM by FL and SERS, respectively. Moreover, the rapid FL imaging and precise SERS quantitative detection for miRNA in cancer cells were also achieved by dual-signal ratio strategy, improving the accuracy of diagnosis. Regarding the therapeutic application, due to the high reactive oxygen species generation ability and excellent photothermal conversion efficiency, the ACSPs can also act as an all-in-one nanoagent for multimodal collaborative tumor therapy. Significantly, both in vivo and in vitro experiments confirmed its high biological safety and strong anticancer effect, indicating its promising theragnostic applications.

Silver nanoparticles induced cytotoxicity in HT22 cells through autophagy and apoptosis via PI3K/AKT/mTOR signaling pathway

With the widespread application and inevitable environmental exposure, silver nanoparticles (AgNPs) can be accumulated in various organs. More serious concerns are raised on the biological safety and potential toxicity of AgNPs in the central nervous system (CNS), especially in the hippocampus. This study aimed to investigate the biological effects and the role of PI3K/AKT/mTOR signaling pathway in AgNPs mediated cytotoxicity using the mouse hippocampal neuronal cell line (HT22 cells). AgNPs reduced cell viability and induced membrane leakage in a dose-dependent manner, determined by the MTT and LDH assay. In doses of 25, 50, 100 μg mL^-1 for 24 h, AgNPs promoted the excessive production of reactive oxygen species (ROS) and caused the oxidative stress in HT22 cells. AgNPs induced autophagy, determined by the transmission electron microscopy observation, upregulation of LC3 II/I and downregulation of p62 expression levels. The mechanistic investigation showed that the PI3K/AKT/mTOR signaling pathway was activated by phosphorylation, which was enrolled in an AgNP-induced autophagy process. AgNPs could further trigger the apoptosis by upregulation of caspase-3 and Bax and downregulation of Bcl-2 in HT22 cells. These results revealed AgNP-induced cytotoxicity in HT22 cells, which was mediated by autophagy and apoptosis via the PI3K/AKT/mTOR signaling pathway. The study could provide the experimental evidence and explanation for the potential neurotoxicity triggered by AgNPs in vitro.

Mitophagy-lysosomal pathway is involved in silver nanoparticle-induced apoptosis in A549 cells

With the increasing use of silver nanoparticles (AgNPs) in biological materials, the cytotoxicity caused by these particles has attracted much attention. However, the molecular mechanism underlying AgNP cytotoxicity remains unclear. In this study, we aimed to systematically investigate the toxicity induced by AgNP exposure to the lung adenocarcinoma A549 cell line at the subcellular and signaling pathway levels and elucidate the related molecular mechanism. The survival rate of cells exposed to AgNPs at 0, 20, 40, 80, and 160 μg/mL for 24 or 48 h decreased in a dose- and time-dependent manner. AgNPs induced autophagy and mitophagy, determined by the transmission electron microscopy investigation and upregulation of LC3 II/I, p62, PINK1, and Parkin expression levels. AgNP treatment induced lysosomal injury, including the decline of lysosomal membrane integrity and increase in cathepsin B level. The decreased in mitochondrial membrane potential, along with upregulation of cytochrome c, caspases 9 and 3, and BAX/BCL2, further suggested that mitochondrial injury were involved in AgNP-induced apoptosis. In addition, mitochondrial injury may further lead to excessive production of reactive oxygen species and oxidative/ antioxidant imbalance. The results suggested that AgNPs could regulate autophagy via mitochondrial and lysosome injury in A549 cells. The information of the molecular mechanism will provide an experimental basis for the safe application of nanomaterials.

Simultaneous determination of chlorite, chlorate, perchlorate and bromate in ozonated saline by using IC-MS

A simple, accurate and reliable analytical method for simultaneous determination of chlorite, chlorate, perchlorate and bromate in ozonated saline by using ion chromatography coupled with triple quadrupole mass spectrometry (IC-MS) has been developed. The use of silver (Ag) and hydrogen (H) OnGuard cartridges and 100-fold dilution were found to be simple and effective for sample pretreatment. Under optimized MS parameters, method validation was convincingly confirmed. A good linearity was obtained with regression correlation coefficients (R2) larger than 0.999. The mean relative recoveries of chlorite (ClO2-), chlorate (ClO3-), perchlorate (ClO4-), and bromate (BrO3-) ranged from 79.96 to 97.63%. The obtained limit of detection (LOD) was 1.00 μg L-1 for ClO2-, 0.10 μg L-1 for ClO3-, 0.04 μg L-1 for ClO4-, and 0.50 μg L-1 for BrO3-. Chlorate and bromate were only detected in ozonated samples. In addition, the concentration of chlorate and bromate was in direct proportion to the amount of ozone in saline.

Glutathione-S-transferase A3 protein suppresses thiram-induced tibial dyschondroplasia by regulating prostaglandin-related genes expression

Tibial dyschondroplasia (TD) is an intractable avian cartilage disease in which proximal growth plates of tibia lack blood vessels and contain nonviable cells, and it leads to the inflammatory response. Prostaglandins (PGs) genes have not been studied yet in TD chicken, and they might play role in skeletal metabolism, therefore we planned to explore the role of recombinant glutathione-S-transferase A3 (rGSTA3) protein and PG-related genes. In this study, qRT-PCR, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) analysis were used to identify the expression patterns of eight PG-related genes in the tibial growth plate of broiler chicken. The results showed that the expression of PG-related genes glutathione-S-transferase A3 (GSTA3), cyclooxygenase 2 (COX-2), prostaglandin D2 synthase (PTGDS), prostaglandin E synthase (PTGES), prostaglandin E2 receptor (PTGER) 3, PTGER4, prostaglandin reductase 1 (PTGR1) and hematopoietic prostaglandin D synthases (HPGDS) expression were identified and could significantly respond to thiram-induced TD chicken. Interestingly, the expression of rate-limiting enzyme COX-2 and PGE₂ were induced after the treatment of rGSTA3 protein. These findings demonstrated that the occurrence of TD is closely related to the inhibition of PGs. Moreover, rGSTA3 protein participated in the recovery of TD by strengthening the expression of PG-related genes.

[The expression and significance of IGF1R-Ras/RAGE-HMGB1 pathway in colorectal cancer patients with type 2 diabetes mellitus]

Objective: To investigate the expression of IGF1R-Ras and RAGE-HMGB1 signaling pathways in colorectal cancer patients with type 2 diabetes mellitus and their significance. Methods: The resected cancer tissues were obtained from 59 patients with colorectal cancer (CRC), including 29 patients with type 2 diabetes mellitus (CRC/DM group) and 30 with CRC alone (CRC group). The expressions of IGF1R, Ras, RAGE and HMGB1 in cancer tissues were detected by immunohistochemistry. The differences between the two groups were compared and the relationship between the expression and clinicopathological characteristics was analyzed. Results: In CRC/DM group, the positive rates of IGF1R and Ras were both 65.5% (19/29), and 51.7% (15/29) patients had IGF1R+ Ras+ immunophenotype, which were significantly higher than those in CRC group [33.3% (10/30), 36.7% (11/30) and 20.0% (6/30); P=0.013, 0.027 and 0.011, respectively]. The expression of IGF1R and Ras in CRC / DM group was positively correlated (r=0.479, P=0.017). The positive rate of RAGE expression in CRC group and CRC/DM group was 70.0% (21/30) and 72.4% (21/29) respectively, and the positive rate of HMGB1 expression was 46.7% (14/30) and 58.6% (17/29) respectively, neither was observed with significant difference (P=0.358 and 0.838). However, the proportion of patients with RAGE+ HMGB1+ immunophenotype in CRC/DM group [55.2% (16/29)] was higher than that in CRC Group [26.7% (8/30)] which was statistically significant (P=0.026), and the expression of both proteins was positively correlated in CRC/DM group (r=0.578, P=0.003). The clinicopathological analysis showed that in both groups the expression of IGF1R, Ras, RAGE and HMGB1 had no correlation with the sex, age, differentiation degree, tumor length, T stage and lymph node metastasis (P>0.05). Conclusion: Both IGF1R-Ras and RAGE-HMGB1 pathways may be involved in the oncogenesis of colorectal cancer in patients with type 2 diabetes.

Ultrasensitive electrochemical DNA biosensor based on a tetrahedral structure and proximity-dependent surface hybridization

The DNA tetrahedron has developed a broad spectrum of applications in biosensor construction thanks to its excellent mechanical rigidity and structural stability. However, how to construct a highly sensitive biosensor using a DNA tetrahedron is still a challenge. In this work, an ultrasensitive electrochemical biosensor based on a DNA tetrahedral nanostructure was developed with the help of synergy from proximity-dependent hybridization. To decrease the steric hindrance of DNA tetrahedra to proximity-dependent hybridization, the detection signal was set on the inclined side chain structure of a DNA tetrahedral sensing system. Additionally, when the target hybridized with the DNA probe, the ferrocene (Fc) labeled on the end of the DNA probe was driven close to the surface of the biosensor, providing a sensitive faradaic current. The experimental results exhibited a good linear relationship from 1 fM to 10 pM with a linear correlation coefficient of 0.9977, and a high sensitivity with a detection limit of 0.2 fM. Our DNA biosensor also showed good stability according to electrode characterization and target detection at different time scales and the anti-jamming capabilities in a complicated biological extraction environment were excellent. The electrochemical sensing system established here has greatly improved the detection sensitivity of a DNA biosensor based on a DNA tetrahedron, which will further promote its practical applications.

Non-template synthesis of porous carbon nanospheres coated with a DNA-cross-linked hydrogel for the simultaneous imaging of dual biomarkers in living cells

A fluorescent nanoprobe was designed based on porous-carbon nanospheres and DNA hybrid hydrogel for the simultaneous imaging of triphosadenine and biothiol in living cells.

Silver nanoparticles modulate mitochondrial dynamics and biogenesis in HepG2 cells

Silver nanoparticles (AgNPs) are inevitably released into the environment owing to their widespread applications in industry and medicine. The potential of their toxicity has aroused a great concern. Previous studies have shown that AgNPs exposure in HepG2 cells is primarily related to the damage of mitochondria, which includes induction of mitochondrial swelling and increase of intracellular levels of reactive oxygen species (ROS), the collapse of mitochondrial membrane potential and induction of apoptosis through a mitochondrial pathway. In this study, the effects of AgNPs exposure in HepG2 cells on mitochondrial dynamics and biogenesis were investigated. AgNPs were found to induce mitochondrial morphological and structural alterations. The expressions of key proteins (Drp1, Fis1, OPA1, Mff, Mfn1, and Mfn2) related to mitochondrial fission/fusion event were changed. Especially the expression of fission-related protein 1 (p-Drp1) (Ser616) was significantly up-regulated, whereas the expression of mitochondrial biogenesis protein (PGC-1α) was reduced in AgNP-treated cells. Concomitantly, the expression of autophagy marker proteins (LC3B and p62) was increased. The results suggested that AgNPs could trigger cytotoxicity by targeting the mitochondria, resulting in the disruption of mitochondrial function, damage to the mitochondrial structure and morphology, interfering in mitochondrial dynamics and biogenesis. The mitochondria could be a critical target of AgNPs in cells. The functions of mitochondria could be used for assessing the cytotoxic effects associated with AgNPs in cells.

Size-controlled DNA-cross-linked hydrogel coated silica nanoparticles served as a ratiometric fluorescent probe for the detection of adenosine triphosphate in living cells

Herein, we have designed a ratiometric fluorescent nanoprobe for adenosine triphosphate sensing and imaging in living cells, based on silica nanoparticles and a DNA-functionalized hybrid hydrogel. This ratiometric detecting method could validly avoid false-positive signals. Due to its controllable size, favorable biocompatibility and biostability, the nanohydrogel exhibited high cellular permeability and fast response in living cells.

The expression of prostaglandins-related genes in erythrocytes of broiler chicken responds to thiram-induced tibial dyschondroplasia and recombinant glutathione-S-transferase A3 protein

Tibial dyschondroplasia (TD) is a type of bone deformity found in fast-growing chickens, which induce inflammatory responses. Prostaglandins (PGs) implicate in bone formation and bone resorption, associated with inflammation in an autocrine/paracrine manner. This study used qRT-PCR and immunohistochemistry analysis to identify the expression patterns of PG-related genes in the erythrocytes of broiler chickens and explore the effects of thiram-induced TD and the recombinant glutathione-S-transferase A3 (rGSTA3) protein on the expression of PG-related genes: GSTA3, cyclooxygenase 2 (COX-2), prostaglandin D2 synthase (PTGDS), prostaglandin E synthase (PTGES), prostaglandin E2 receptor (PTGER) 3, PTGER4 and prostaglandin reductase 1 (PTGR1). Interestingly, the results showed that these seven PG-related genes expression was identified in the erythrocytes of broiler chicken, and thiram-induced TD suppressed the expression of these PG-related genes in the initial stage of TD and promoted their expression in TD recovery. These findings demonstrated that the immunoregulatory function of erythrocytes can be inhibited in the early stage of TD and promoted in the recovery stage by modulating the expression of PG-related genes. Further, the rGSTA3 protein can modulate the expression of PG-related genes in erythrocytes and participate in the recovery of TD.

On-site Method for Beef Detection Based on Strand Exchange Amplification

Meat screening plays a significant role in human health and religion. But the identification methods for beef were little reported. In this work, a simple colorimetric method based on denaturation bubble-mediated strand exchange amplification (SEA) was developed for the rapid and sensitive identification of beef. The whole strategy was performed on a portable metal bath and the distinguishable color between positive and negative controls was observed directly by the naked eyes. The feasibility using crude extraction samples by a heating treatment in PBS for 2 min was evaluated in duck spiked by beef. The result demonstrated that the developed method could identify as low as 1% (w/w) beef/duck within 50 min. Meanwhile, the results showed the method had a good repeatability and specificity. Therefore, this assay allows for the rapid, sensitive, specific detection of beef, and can be recommended as an effective, promising strategy for on-site meat identification.

An ultrafast one-step assay for the visual detection of RNA virus

A one-step, rapid, and visual method was developed for the detection of RNA viruses and a few copies of the Zika RNA virus were directly detected within 25 min by naked-eye observation. This method will prove to be promising for point-of-care testing in out-of-lab and inconvenient settings.

Comparison of vertical and horizontal swimming behaviour of the weather loach Misgurnus anguillicaudatus

Experiments on the swimming kinetics and behaviour of weather loach Misgurnus anguillicaudatus showed that horizontal swim speed was significantly greater than swim speeds when ascending to or descending from the water surface to gulp air. Vertical swimming speeds during ascending or descending were similar. Misgurnus anguillicaudatus swam unsteadily during vertical movements compared with horizontal movements.

Quantitative Analysis of Unidirectional 2-D Tissue Formation of Endothelial Cells

We developed a reliable and quantitative method for measuring the dynamic process of unidirectional two-dimensional (2-D) tissue formation of endothelial cells (ECs) in vitro. The culturing of bovine ECs in an assembled culture chamber provided a square monolayered cell sheet with a linear margin when disassembled at the confluency. The cell sheet maintained in culture showed a unidirectional endothelialization in vitro. The cell population-distance histogram, which was determined from the daily observation of tissue, allowed us to determine quantitatively the dynamic process of unidirectional endothelialization in vitro. The endothelialized distance and the endothelializing zone on a glass slide were found to be nearly 500 μm/day and 750 μm in width, respectively. Thus, the method developed here provided information of the 2-D tissue formation process. This model would be useful as an in vitro model which simulates the anastomotic endothelialization of an artificial vascular graft.

PEGylated Polyaniline Nanofibers: Antifouling and Conducting Biomaterial for Electrochemical DNA Sensing

Biofouling arising from nonspecific adsorption is a substantial outstanding challenge in diagnostics and disease monitoring, and antifouling sensing interfaces capable of reducing the nonspecific adsorption of proteins from biological complex samples are highly desirable. We present herein the preparation of novel composite nanofibers through the grafting of polyethylene glycol (PEG) polymer onto polyaniline (PANI) nanofibers and their application in the development of antifouling electrochemical biosensors. The PEGylated PANI (PANI/PEG) nanofibers possessed large surface area and remained conductive and at the same time demonstrated excellent antifouling performances in single protein solutions as well as complex human serum samples. Sensitive and low fouling electrochemical biosensors for the breast cancer susceptibility gene (BRCA1) can be easily fabricated through the attachment of DNA probes to the PANI/PEG nanofibers. The biosensor showed a very high sensitivity to target BRCA1 with a linear range from 0.01 pM to 1 nM and was also efficient enough to detect DNA mismatches with satisfactory selectivity. Moreover, the DNA biosensor based on the PEGylated PANI nanofibers supported the quantification of BRCA1 in complex human serum, indicating great potential of this novel biomaterial for application in biosensors and bioelectronics.