A fluorescence probe with targeted mitochondria for detecting hydrogen peroxide in vitro and in diabetic mice.

We designed and prepared probe W-1 for the detection of H2O2. W-1 showed excellent selectivity for H2O2 and was accompanied by colorimetric signal changes. The excellent linear relationship between fluorescence intensity and H2O2 concentration (0-100 µM) provided favorable conditions for its quantitative detection. In addition, the combination of portable test strips with a smartphone platform provided great convenience for on-site visual detection of H2O2. Moreover, W-1 possessed targeting mitochondria property and could be applied to image the exogenous and endogenous H2O2 in cells to distinguish normal cells and cancer cells. Lastly, W-1 was used for monitoring the H2O2 fluctuation of the diabetic process in mice, and the results showed an increase in H2O2 levels in diabetes. Therefore, the probe provided a tool for understanding the pathological and physiological mechanisms of diabetes by imaging H2O2.

Development of the near-infrared fluorescence probe for detection of ONOO- and its application in vitro and vivo.

Diabetes has become one of the most common endocrine and metabolic diseases threatening human health, which can induce mitochondrial dysfunction and exacerbate the excessive production of reactive oxygen species (ROS). Among them, ONOO- level fluctuation was closely related to diabetes. Hence, it is of great significance to develop a near-infrared fluorescence probe for visualizing ONOO- level fluctuations in diabetes. In this paper, we constructed a fluorescence probe YBL with dicyano-isophorone derivative as fluorophore and diphenyl phosphate as ONOO- response site, which can detect ONOO- with the low detection limit (39.8 nM) and exhibit excellent selectivity and sensitivity. The probe YBL has been applied to monitor intracellular ONOO- level fluctuations. Meanwhile, the image results showed that high sugar promoted the increase of ONOO- level in cells. More important, the probe YBL can be used for imaging in mice, and the results showed that content of ONOO- was increased in diabetic mice. Therefore, the probe YBL provided a tool for understanding diabetes progression by imaging ONOO-.

Single-particle Förster resonance energy transfer from upconversion nanoparticles to organic dyes.

Single-particle detection and sensing, powered by Förster resonance energy transfer (FRET), offers precise monitoring of molecular interactions and environmental stimuli at a nanometric resolution. Despite its potential, the widespread use of FRET has been curtailed by the rapid photobleaching of traditional fluorophores. This study presents a robust single-particle FRET platform utilizing upconversion nanoparticles (UCNPs), which stand out for their remarkable photostability, making them superior to conventional organic donors for energy transfer-based assays. Our comprehensive research demonstrates the influence of UCNPs' size, architecture, and dye selection on the efficiency of FRET. We discovered that small particles (∼14 nm) with a Yb3+-enriched outermost shell exhibit a significant boost in FRET efficiency, a benefit not observed in larger particles (∼25 nm). 25 nm UCNPs with an inert NaLuF4 shell demonstrated a comparable level of emission enhancement via FRET as those with a Yb3+-enriched outermost shell. At the single-particle level, these FRET-enhanced UCNPs manifested an upconversion green emission intensity that was 8.3 times greater than that of their unmodified counterparts, while maintaining notable luminescence stability. Our upconversion FRET system opens up new possibilities for developing more effective high-brightness, high-sensitivity single-particle detection, and sensing modalities.

Corrigendum: Mechanotransductive receptor Piezo1 as a promising target in the treatment of fibrosis diseases.

[This corrects the article DOI: 10.3389/fmolb.2023.1270979.].

The highly selective and sensitive fluorescence probe for detection of copper (II) ions and its bioimaging in vitro and vivo.

We designed and developed the probe W-3 for detection of Cu2+. The results showed probe can selectively detect Cu2+, accompanied by noticeable color change. The probe can detect the Cu2+ in water samples and drinks based on absorption detection. In addition, the combination of portable test paper and the smartphone platform obtained great convenience for on-site and visual detection of Cu2+, with satisfactory sensitivity and reliability. More importantly, the fluorescence probe W-3 can be used for the detection of Cu2+ in cells and mice. Therefore, the W-3 provided potential chemical tools for detecting Cu2+ in vitro and vivo.

SdrR, a LysR-type regulator, responds to the mycobacterial antioxidant defense.

Protection against oxidative stress is a vital defense mechanism for Mycobacterium tuberculosis within the host. However, few transcription factors that control bacterial antioxidant defense are known. Here, we present evidence that SdrR, encoded by the MSMEG_5712 (Ms5712) gene, functions as an oxidative stress response regulator in Mycobacterium smegmatis. SdrR recognizes an 11-bp motif sequence in the operon's upstream regulatory region and negatively regulates the expression of short-chain dehydrogenases/reductases (SDR). Overexpressing sdrR inhibited SDR expression, which rendered the strain oxidative more stress-sensitive. Conversely, sdrR knockout alleviates SDR repression, which increases its oxidative stress tolerance. Thus, SdrR responds to oxidative stress by negatively regulating sdr expression. Therefore, this study elucidated an underlying regulatory mechanism behind mycobacterial oxidative stress adaptation.

Multifunctional fluorescence probe for simultaneous detection of viscosity, polarity, and ONOO- and its bioimaging in vitro and vivo.

Intracellular microenvironment (viscosity and polarity) and peroxynitrite ions (ONOO-) are involved in maintaining cell morphology, cell function, and signaling so that it is crucial to explore their level changes in vitro and vivo. In this work, we designed and synthesized a mitochondria-targeted fluorescence probe XBL for monitoring the dynamic changes of viscosity, polarity, and ONOO- based on TICT and ICT mechanism. The fluorescence spectra showed obvious changes for polarity at 500 nm as well as ONOO- and viscosity at 660 nm, respectively. The XBL can image simultaneously viscosity, polarity, and ONOO- in cells, and the results showed excess ONOO- leaded to the increase of viscosity in mitochondrial. The ferroptosis process was accompanied by increase of intracellular viscosity and ONOO- levels (or decrease of polarity), which allowed us to better understand the relevant physiological and pathological processes. The XBL can distinguish normal cells and cancerous cells by the fluorescence intensity changes in green and red channels, and image viscosity in inflamed mice. Thus, XBL can provided the chemical tool to understand the physiological and pathological mechanisms of disease by simultaneous detection of viscosity, polarity and ONOO-.

Effect of Surface Modification on the Luminescence of Individual Upconversion Nanoparticles.

Lanthanide-doped upconversion nanoparticles (UCNPs) hold promise for single-molecule imaging owing to their excellent photostability and minimal autofluorescence. However, their limited water dispersibility, often from the hydrophobic oleic acid ligand during synthesis, is a challenge. To address this, various surface modification strategies' impact on single-particle upconversion luminescence are studied. UCNPs are made hydrophilic through methods like ligand exchange with dye IR806, HCl or NOBF4 treatment, silica coating (SiO2 or mesoporous mSiO2), and self-assembly with polymer of DSPE-PEG or F127. The studies revealed that UCNPs modified with NOBF4 and DSPE-PEG exhibited notably higher single-particle brightness with minimal quenching (3% and 8%, respectively), followed by SiO2, F127, IR806, mSiO2, and HCl (84% quenching). HCl disrupted UCNPs's crystal lattice, weakening luminescence, while mSiO2 absorbed solvent molecules, causing luminescence quenching. Energy transfer to IR806 also reduced the brightness. Additionally, a prevalence of upconversion red emission over green is observed, with the red-to-green ratio increasing with irradiance. UCNPs coated with DSPE-PEG exhibited the brightest single-particle luminescence in water, retaining 48% of its original emission due to a lower critical micelle concentration and superior water protection. In summary, the investigation provides valuable insights into the role of surface chemistry on UCNPs at the single-particle level.

Role of the P2 × 7 receptor in neurodegenerative diseases and its pharmacological properties.

Neurodegenerative diseases seriously affect patients' physical and mental health, reduce their quality of life, and impose a heavy burden on society. However, their treatment remains challenging. Therefore, exploring factors potentially related to the pathogenesis of neurodegenerative diseases and improving their diagnosis and treatment are urgently needed. Recent studies have shown that P2 × 7R plays a crucial role in regulating neurodegenerative diseases caused by neuroinflammation. P2 × 7R is an adenosine 5'-triphosphate ligand-gated cation channel receptor present in most tissues of the human body. An increase in P2 × 7R levels can affect the progression of neurodegenerative diseases, and the inhibition of P2 × 7R can alleviate neurodegenerative diseases. In this review, we comprehensively describe the biological characteristics (structure, distribution, and function) of this gene, focusing on its potential association with neurodegenerative diseases, and we discuss the pharmacological effects of drugs (P2 × 7R inhibitors) used to treat neurodegenerative diseases.

NLRP3 inflammasome in cognitive impairment and pharmacological properties of its inhibitors.

Cognitive impairment is a multifactorial and multi-step pathological process that places a heavy burden on patients and the society. Neuroinflammation is one of the main factors leading to cognitive impairment. The inflammasomes are multi-protein complexes that respond to various microorganisms and endogenous danger signals, helping to initiate innate protective responses in inflammatory diseases. NLRP3 inflammasomes produce proinflammatory cytokines (interleukin IL-1ß and IL-18) by activating caspase-1. In this review, we comprehensively describe the structure and functions of the NLRP3 inflammasome. We also explore the intrinsic relationship between the NLRP3 inflammasome and cognitive impairment, which involves immune cell activation, cell apoptosis, oxidative stress, mitochondrial autophagy, and neuroinflammation. Finally, we describe NLRP3 inflammasome antagonists as targeted therapies to improve cognitive impairment.

Identification of signature of tumor-infiltrating CD8 T lymphocytes in prognosis and immunotherapy of colon cancer by machine learning.

BACKGROUND: To explore the specific marker of CD8+ T cell subsets which are closely related to the prognosis and immunotherapy of patients with colon cancer. METHODS: 18 kinds of immune cell expression profile data sets were obtained from GEO database. Compared with other immune cell types, the specific markers of CD8 (+) T cells (TI-CD8) in colorectal cancer were screened. Regression analyses were used to further screen prognostic related genes and construct a prognostic evaluation model. The patients were stratified and analyzed according to the risk scores, KRAS mutation status, stage, lymphatic infiltration and other indicators. The landscape of infiltration level, mutation and copy number variation of immune subsets in high and low TI-CD8Sig score groups were compared and analyzed. The difference of drug response between high and low TI-CD8Sig score groups was analyzed. Differential expression of the model genes was verified by the HPA database. RESULTS: Six prognostic-related CD8T cell-specific gene targets were further screened, and the prognostic evaluation model was constructed. The AUC value of the model is >0.75. FAT3 and UNC13C showed a high mutation state in the low-risk group, while USH2A, MUC5B et al. specifically showed a high mutation state in the high-risk group. Compared with the low-risk group, the high-risk group had lower effective rate of drug response. The expression of PD-1 gene was positively correlated with the level of TI-CD8Sig score. CONCLUSION: The risk assessment model based on CD8T cell-specific marker genes can effectively predict the prognosis and the drug response of patients with CRC.

Mechanotransductive receptor Piezo1 as a promising target in the treatment of fibrosis diseases.

Fibrosis could happen in every organ, leading to organic malfunction and even organ failure, which poses a serious threat to global health. Early treatment of fibrosis has been reported to be the turning point, therefore, exploring potential correlates in the pathogenesis of fibrosis and how to reverse fibrosis has become a pressing issue. As a mechanism-sensitive cationic calcium channel, Piezo1 turns on in response to changes in the lipid bilayer of the plasma membrane. Piezo1 exerts multiple biological roles, including inhibition of inflammation, cytoskeletal stabilization, epithelial-mesenchymal transition, stromal stiffness, and immune cell mechanotransduction, interestingly enough. These processes are closely associated with the development of fibrotic diseases. Recent studies have shown that deletion or knockdown of Piezo1 attenuates the onset of fibrosis. Therefore, in this paper we comprehensively describe the biology of this gene, focusing on its potential relevance in pulmonary fibrosis, renal fibrosis, pancreatic fibrosis, and cardiac fibrosis diseases, except for the role of drugs (agonists), increased intracellular calcium and mechanical stress using this gene in alleviating fibrosis.

Chitosan biomaterial enhances the effect of OECs on the inhibition of sciatic nerve injury-induced neuropathic pain.

Neuropathic pain is a common symptom experienced by most clinical diseases at different levels, and its treatment has always been a clinical difficulty. Therefore, it is particularly important to explore new and effective treatment methods. The role of olfactory ensheathing cells (OECs) in nerve injury and pain is recognized by different studies. Our previous study found that transplantation of OECs alleviated hyperalgesia in rats. However, single-cell transplantation lacks medium adhesion and support, and exerts limited analgesic effect. Therefore, on the basis of the previous study, this study investigated the effect of pain relief by co-transplanting OECs with chitosan (CS) (a biological tissue engineering material, as OECs were transplanted into the host medium) to the injured sciatic nerve. The results showed that the pain threshold of sciatic nerve injury of rats was significantly reduced, and the expression level of P2×4 receptor in the spinal cord was significantly increased. While olfactory ensheathing cells combined with chitosan (OECs+CS) transplantation could significantly relieve pain, and the analgesic effect was stronger than that of OECs transplantation alone. OECs+CS transplantation promoted the formation of sciatic nerve remyelination, improved the changes of demyelination, and promoted the repair of sciatic nerve injury more significantly. In addition, the effect of OECs+CS to down-regulate the expression of P2×4 receptor was significantly stronger than that of OECs transplantation, and exerted a better analgesic effect. These data reveal that OECs+CS have a better analgesic effect in relieving neuropathic pain induced by sciatic nerve injury, and provide a new therapeutic strategy for pain treatment.

Boosting Dye-Sensitized Luminescence by Enhanced Short-Range Triplet Energy Transfer.

Dye-sensitization can enhance lanthanide-based upconversion luminescence, but is hindered by interfacial energy transfer from organic dye to lanthanide ion Yb3+ . To overcome these limitations, modifying coordination sites on dye conjugated structures and minimizing the distance between fluorescence cores and Yb3+ in upconversion nanoparticles (UCNPs) are proposed. The specially designed near-infrared (NIR) dye, disulfo-indocyanine green (disulfo-ICG), acts as the antenna molecule and exhibits a 2413-fold increase in luminescence under 808 nm excitation compared to UCNPs alone using 980 nm irradiation. The significant improvement is attributed to the high energy transfer efficiency of 72.1% from disulfo-ICG to Yb3+ in UCNPs, with majority of energy originating from triplet state (T1 ) of disulfo-ICG. Shortening the distance between the dye and lanthanide ions increases the probability of energy transfer and strengthens the heavy atom effect, leading to enhanced T1 generation and improved dye-triplet sensitization upconversion. Importantly, this approach also applies to 730 nm excitation Cy7-SO3 sensitization system, overcoming the spectral mismatch between Cy7 and Yb3+ and achieving a 52-fold enhancement in luminescence. Furthermore, the enhancement of upconversion at single particle level through dye-sensitization is demonstrated. This strategy expands the range of NIR dyes for sensitization and opens new avenues for highly efficient dye-sensitized upconversion systems.

High dynamic reflection surface 3D reconstruction with sharing phase demodulation mechanism and multi-indicators guided phase domain fusion.

Accurate and complete 3D measurement of complex high dynamic range (HDR) surfaces has been challenging for structured light projection technique. The behavior of spraying a layer of diffuse reflection material, which will inevitably incur additional thickness. Existing methods based on additional facilities will increase the cost of hardware system. The algorithms-based methods are cost-effective and nondestructive, but they generally require redundant patterns for image fusion and model training, which fail to be suitable for practicing automated 3D measurement for complex HDR surfaces. In this paper, a HDR surface 3D reconstruction method based on sharing demodulation phase unwrapping mechanism and multi-indicators guided phase fusion strategy is proposed. The division of the exposure interval is optimized via the image entropy to generate an optimal exposure sequence. The combination of temporal-spatial binary (TSB) encoding fringe patterns with time-integration strategy and the variable exposure mode of digital mirror device (DMD)-based projector with a minimum projection exposure time of 233µs enables the proposed approach to broadly adapt complex HDR surfaces. We propose an efficient phase analysis solution called sharing mechanism that wrapped phase sequences from captured different intensity fringe images are unwrapped through sharing the same group of misaligned Gray code (MGC) decoding result. Finally, a phase sequences fusion model guided by multi-indicators, including exposure quality, phase gradient smoothness and pixel effectiveness, is established to obtain an optimum phase map for final 3D reconstruction. Comparative experiments indicate that the proposed method can completely restore the 3D topography of HDR surfaces with the images reduction of at least 65% and the measurement integrity is maintained at over 98% while preserving the measurement accuracy and excluding the outliers.

Identification of inflammatory factor-related genes associated with the prognosis and immune cell infiltration in colorectal cancer patients.

This study aims to identify the inflammatory factor-related genes which help to predict the prognosis of patients with colorectal cancer. GSEA (Gene Set Enrichment Analysis) was used to acquire inflammation-related genes and the corresponding expression information was collected from TCGA database to determine the DEGs (differentially-expressed genes) in CRC patients. We conducted enrichment analysis and PPI (protein-protein interaction) of these DEGs. Besides, key genes that are both differentially-expressed and prognosis-related were screened out, which were used to establish the prognostic model. We obtained 79 DEGs and 19 prognostic genes, 10 prognostic-related differential genes were eventually screened. These genes were used to construct the prognostic model. We also identified that the immune infiltration score of macrophages between different risk groups was significantly different and similar distinction was witnessed in immune function score of APC (antigen-presenting cell) co-stimulation and type I IFN (interferon) response.

P2Y12 receptor involved in the development of chronic nociceptive pain as a sensory information mediator.

Direct or indirect damage to the nervous system (such as inflammation or tumor invasion) can lead to dysfunction and pain. The generation of pain is mainly reflected in the activation of glial cells and the abnormal discharge of sensory neurons, which transmit stronger sensory information to the center. P2Y12 receptor plays important roles in physiological and pathophysiological processes including inflammation and pain. P2Y12 receptor involved in the occurrence of pain as a sensory information mediator, which enhances the activation of microglia and the synaptic plasticity of primary sensory neurons, and reaches the higher center through the ascending conduction pathway (mainly spinothalamic tract) to produce pain. While the application of P2Y12 receptor antagonists (PBS-0739, AR-C69931MX and MRS2359) have better antagonistic activity and produce analgesic pharmacological properties. Therefore, in this article, we discussed the role of the P2Y12 receptor in different chronic pains and its use as a pharmacological target for pain relief.

Squaraine Dye-Sensitized Upconversion with Enhanced Stability and Minimized Aggregation-Caused Quenching.

Upconversion nanoparticles (UCNPs) doped with lanthanides have limited brightness due to their small absorption cross section to light. However, using organic sensitizers can significantly enhance their light absorption ability. Unfortunately, the practical application of organic sensitizers has been hindered by poor stability and aggregation-caused quenching (ACQ). To address these issues, we developed a novel squaraine-based dye, SQ-739, for sensitizing upconversion luminescence (UCL). This dye has a maximum absorption at 739 nm, and shows 1 order of magnitude and 2-fold improved chemical- and photostability, compared to the commonly used cyanine-based dye IR-806, respectively. When SQ-739 is used to sensitize UCNPs, the resulting SQ-739-UCNPs exhibit excellent photostability and reduced ACQ in the presence of polar solvents. Moreover, at the single particle level, the SQ-739-UCNPs exhibit a 97-fold increase in UCL emission compared to bare UCNPs. This squaraine dye-based system represents a new design strategy for developing highly stable and efficient NIR upconversion probes.

Hsp22 pretreatment protects against LPS-induced hippocampal injury by alleviating neuroinflammation and apoptosis by regulating the NLRP3/Caspase1/IL-1ß signaling pathway in mice.

Neuroinflammation is an important reason for the occurrence and development of cognitive impairment. The Lentiviral vector Hsp22 was constructed for intracerebroventricular injection pretreatment, LPS was used to induce the cognitive impairment model in mice, and the Morris water maze was used to examine the changes in cognitive behavior in mice. LPS was used to induce BV-2 microglial cells, and plasmid pretreatment was used to overexpress Hsp22. HE staining, Nissl staining, immunohistochemistry, immunofluorescence, ELISA and protein blotting were used to examine microglial activation, changes in inflammatory factors, changes in pathway proteins and apoptosis. The results showed that LPS induced microglial expression of NLRP3/Caspase-1/IL-1ß signaling pathway protein Iba1, and the inflammatory protein and inflammatory factors IL-1ß, IL-6 and TNF-α, the expression of Bax increased significantly, Bcl2 expression decreased, and the learning and memory abilities of mice decreased significantly. Preconditioning with the Hsp22-overexpressing lentivirus attenuated LPS-induced activation of hippocampal microglia, the expression of inflammatory factors and pathway proteins, and apoptosis, and improved cognitive impairment in mice. In addition, plasmid-mediated Hsp22 overexpression reversed LPS-induced inflammation. These findings suggest that Hsp22 overexpression is a promising method for the treatment of cognitive impairment.

Analysis of microplastics released from plastic take-out food containers based on thermal properties and morphology study.

Plastic take-out food containers may release microplastics (MPs) into food and pose a potential risk to food safety and human health. Here, after being subjected to hot water treatment, MPs released from three types of plastic food containers (polypropylene, PP; polyethylene, PE; expanded polystyrene, EPS) were identified by micro-Raman spectroscopy. The results showed that the size of released MPs ranged from 0.8-38 µm and over 96% MPs were smaller than 10 µm. Various MPs concentrations were found from the three types of containers, that is, 1.90 × 104, 1.01 × 105, and 2.82 × 106 particles/L on average from PP, PE, and EPS, respectively. Moreover, based on thermal and morphology analysis, we discovered that both relaxations of the polymer chains in the rubbery state and defects caused by processing techniques might contribute to the release of MPs. Thus, such release can be reduced by increasing the thermal stability of the materials and mitigating the defects generated during production.