Effects of Selenium and Cadmium on Human Liver and Kidney Functions in Exposed Black Shale Areas.

Animal experiments suggest that selenium (Se) may alleviate cadmium (Cd) toxicity in animal liver and kidneys, but its effect on human liver and kidneys remains uncertain. In China, areas with black shale have shown elevated levels of Se and Cd. According to the USEPA (U.S. Environmental Protection Agency) evaluation method, the soil and rice in these areas pose significant risks. In black shale regions such as Enshi and Zhuxi County, residents who long-term consume local rice may surpass safe Se and Cd intake levels. Significantly high median blood Se (B-Se) and urine selenium (U-Se) levels were detected in these areas, measuring 416.977 µg/L and 352.690 µg/L and 104.527 µg/L and 51.820 µg/L, respectively. Additionally, the median blood Cd (B-Cd) and urine Cd (U-Cd) levels were markedly elevated at 4.821 µg/L and 3.848 µg/L and at 7.750 µg/L and 7.050 µg/L, respectively, indicating substantial Cd exposure. Nevertheless, sensitive liver and kidney biomarkers in these groups fall within healthy reference ranges, suggesting a potential antagonistic effect of Se on Cd in the human body. Therefore, the USEPA method may not accurately assess Cd risk in exposed black shale areas. However, within the healthy ranges, residents in the Enshi study area had significantly greater median levels of serum creatinine and cystatin C, measuring 67.3 µmol/L and 0.92 mg/L, respectively, than those in Zhuxi did (53.6 µmol/L and 0.86 mg/L). In cases of excessive Se and Cd exposure, high Se and Cd levels impact the filtration function of the human kidney to some extent.

Multifunctional self-healing peptide hydrogel for wound healing.

The complete healing of wounds remains a challenge in clinical care. In addition, various complications such as inflammation and infection that may occur during skin wound healing can impede the healing process. Here, we constructed a multifunctional self-repairing hydrogel by utilizing Schiff base bonds. This hydrogel exhibited good self-healing properties and could cope with destructive external influences. The self-healing hydrogel was injectable, ensuring that the hydrogel dressing adhered to the wound. Carboxymethyl chitosan and oxidized chondroitin sulfate demonstrated good biocompatibility and multiple bioactivities and were successfully used to prepare self-healing hydrogels. Meanwhile, the SIKVAV biopeptide was less expensive and more morphologically stable than vascular endothelial growth factor and had a high pro-angiogenic activity. Thus, the SIKVAV biopeptide was cross-linked to the oxidized chondroitin sulfate of the hydrogel through covalent bonding to avoid rapid biopeptide degradation, achieving a slow release of the drug. This peptide hydrogel exhibited good biocompatibility and antimicrobial properties; moreover, experiments conducted on mice revealed that it could effectively promote angiogenesis and skin tissue repair. These findings suggest that the injectable self-repairing peptide hydrogel may facilitate skin wound healing and other applications.

Tumor Site-Specific Cleavage Improves the Antitumor Efficacy of Antibody-Drug Conjugates.

Antibody-drug conjugates (ADCs) play important roles in tumor therapy. However, traditional ADCs are limited by the extremely large molecular weight of the antibody molecules, which results in low permeability into solid tumors. The use of small ADCs may be expected to alleviate this problem, but this switch brings the new limitation of a greatly shortened blood circulation half-life. Here, we propose a new cleavable ADC design with excellent tumor tissue permeability and a long circulation half-life by fusing the small ADC ZHER2-MMAE with the Fc domain of the antibody for circulation half-life extension, and inserting a digestion sequence between them to release the small ADC inside tumors for better tumor penetration. The experimental results showed that the designed molecule Fc-U-ZHER2-MMAE has a significantly increased blood circulation half-life (7.1 h, 59-fold longer) compared to the small ADC ZHER2-MMAE, and significantly improved drug accumulation ability at tumor sites compared to the conventional full-length antibody-coupled ADC Herceptin-MMAE. These combined effects led to Fc-U-ZHER2-MMAE having significantly enhanced tumor treatment ability, as shown in mouse models of NCI-N87 gastric cancer and SK-OV-3 ovarian cancer, where Fc-U-ZHER2-MMAE treatment achieved complete regression of tumors in all or a portion of animals with no obvious side effects and an MTD exceeding 90 mg/kg. These data demonstrate the therapeutic advantages of this cleavable ADC strategy, which could provide a new approach for ADC design.

Do high soil geochemical backgrounds of selenium and associated heavy metals affect human hepatic and renal health? Evidence from Enshi County, China.

It is unclear whether the United States Environmental Protection Agency (US EPA) method can accurately assess heavy metal risks in high-Se areas. Herein, a black shale outcropping in Enshi County, China, was taken as the study area, and a carbonate outcropping in Lichuan County was the control area. Selenium and associated heavy metal concentrations in rock, soil, rice, human blood and urine samples and human sensitive hepatic and renal biomarkers were measured. The results showed that the contents of selenium, cadmium, molybdenum and copper in the study area were 3.68 ± 2.72 µg/g, 2.65 ± 1.42 µg/g, 16.3 ± 15.5 µg/g, and 57.3 ± 17.6 µg/g, respectively, in soil (n = 47) and 1.072 ± 0.924 µg/g, 0.252 ± 0.310 µg/g, 2.800 ± 2.167 µg/g, and 10.91 ± 27.42 µg/g, respectively, in rice (n = 47). The daily adult intake levels of selenium, cadmium and molybdenum from rice consumption in the study area (exposure group) exceed the recommended tolerance values in China. According to the US EPA method, these environmental media pose a significant risk to human health. However, in the exposure group (n = 111), the median levels of the sensitive hepatic biomarkers alanine aminotransferase (18 U/L), aspartate aminotransferase (28 U/L) and total bilirubin (10.9 µmol/L) and the sensitive renal biomarkers serum creatinine (70.1 µmol/L), urinary nitrogen (5.73 mmol/L) and uric acid (303.80 µmol/L) were within reference ranges and had values equivalent to those of the control group (P > 0.05). The elements tended to differentiate during migration from one medium to another. Due to the complex interaction between selenium and heavy metals, a survey of human health indicators is indispensable when the US EPA method is used to assess the heavy metal risks in high-Se areas. The recommended molybdenum tolerable intake in the U.S. (2000 µg/d) is reasonable based on a comparison.

Improvement in osteogenesis, vascularization, and corrosion resistance of titanium with silicon-nitride doped micro-arc oxidation coatings.

Titanium (Ti) implants have been widely used for the treatment of tooth loss due to their excellent biocompatibility and mechanical properties. However, modifying the biological properties of these implants to increase osteointegration remains a research challenge. Additionally, the continuous release of various metal ions in the oral microenvironment due to fluid corrosion can also lead to implant failure. Therefore, simultaneously improving the bioactivity and corrosion resistance of Ti-based materials is an urgent need. In recent decades, micro-arc oxidation (MAO) has been proposed as a surface modification technology to form a surface protective oxide layer and improve the comprehensive properties of Ti. The present study doped nano silicon nitride (Si3N4) particles into the Ti surface by MAO treatment to improve its corrosion resistance and provide excellent osteoinduction by enhancing alkaline phosphatase activity and osteogenic-related gene expression. In addition, due to the presence of silicon, the Si3N4-doped materials showed excellent angiogenesis properties, including the promotion of cell migration and tubule formation, which play essential roles in early recovery after implantation.

A Potent Micron Neoantigen Tumor Vaccine GP-Neoantigen Induces Robust Antitumor Activity in Multiple Tumor Models.

Therapeutic tumor neoantigen vaccines have been widely studied given their good safety profile and ability to avoid central thymic tolerance. However, targeting antigen-presenting cells (APCs) and inducing robust neoantigen-specific cellular immunity remain challenges. Here, a safe and broad-spectrum neoantigen vaccine delivery system is proposed (GP-Neoantigen) based on ß-1,3-glucan particles (GPs) derived from Saccharomyces cerevisiae and coupling peptide antigens with GPs through convenient click chemistry. The prepared system has a highly uniform particle size and high APC targeting specificity. In mice, the vaccine system induced a robust specific CD8+ T cell immune response and humoral immune response against various conjugated peptide antigens and showed strong tumor growth inhibitory activity in EG7·OVA lymphoma, B16F10 melanoma, 4T1 breast cancer, and CT26 colon cancer models. The combination of the toll-like receptors (TLRs) agonist PolyI:C and CpG 2395 further enhanced the antitumor response of the particle system, achieving complete tumor clearance in multiple mouse models and inducing long-term rejection of reinoculated tumors. These results provide the broad possibility for its further clinical promotion and personalized vaccine treatment.

A Single-Domain Antibody-Based Anti-PSMA Recombinant Immunotoxin Exhibits Specificity and Efficacy for Prostate Cancer Therapy.

Prostate cancer (PCa) is the second most common cancer in men, causing more than 300,000 deaths every year worldwide. Due to their superior cell-killing ability and the relative simplicity of their preparation, immunotoxin molecules have great potential in the clinical treatment of cancer, and several such molecules have been approved for clinical application. In this study, we adopted a relatively simple strategy based on a single-domain antibody (sdAb) and an improved Pseudomonas exotoxin A (PE) toxin (PE24X7) to prepare a safer immunotoxin against prostate-specific membrane antigen (PSMA) for PCa treatment. The designed anti-PSMA immunotoxin, JVM-PE24X7, was conveniently prepared in its soluble form in an Escherichia coli (E. coli) system, avoiding the complex renaturation process needed for immunotoxin preparation by the conventional strategy. The product was very stable and showed a very strong ability to bind the PSMA receptor. Cytotoxicity assays showed that this molecule at a very low concentration could kill PSMA-positive PCa cells, with an EC50 value (concentration at which the cell viability decreased by 50%) of 15.3 pM against PSMA-positive LNCaP cells. Moreover, this molecule showed very good killing selectivity between PSMA-positive and PSMA-negative cells, with a selection ratio of more than 300-fold. Animal studies showed that this molecule at a very low dosage (5 × 0.5 mg/kg once every three days) completely inhibited the growth of PCa tumors, and the maximum tolerable dose (MTD) was more than 15 mg/kg, indicating its very potent tumor-treatment ability and a wide therapeutic window. Use of the new PE toxin, PE24X7, as the effector moiety significantly reduced off-target toxicity and improved the therapeutic window of the immunotoxin. The above results demonstrate that the designed anti-PSMA immunotoxin, JVM-PE24X7, has good application value for the treatment of PCa.

Preclinical evaluation of a novel anti-mesothelin immunotoxin based on a single domain antibody as the targeting ligand.

Pancreatic cancer, as one of the most aggressive and lethal malignancies in the world, is lack of effective treatment. Constructing immunotoxin molecules to target the mesothelin (MSLN) receptor is a potential therapeutic strategy for pancreatic cancer and other related malignant tumors, with some molecules being tested in clinical trials. However, currently, there are still some limitations in its applications, such as the difficulty of the preparation of drug molecules, the limited effectiveness of drugs, and the inadequacy of drug safety and immunogenicity. In this study, we constructed a novel type of anti-MSLN immunotoxin, A1-PE24X7, in which a single domain antibody (sdAb) molecule was used as the target ligand and an improved PE24X7 toxin with reduced off-target toxicity and immunogenicity was used as the effector. Unlike conventional immunotoxins, the designed A1-PE24X7 could be easily expressed in the E. coli system in the form of a soluble protein with a good yield (15--20 mg/L), avoiding the complex process of denaturation and refolding of inclusion bodies, and it can be conveniently stored in PBS solution for more than 7 days at 4 °C, showing high storage stability. Cell-based experiments showed that A1-PE24X7 entered MSLN-expressing tumor cells in a receptor-mediated manner and killed these cells with an EC50 in the low nanomolar range (0.13 nM against NCI-N87 cells and 0.79 nM against AsPC-1 cells) and it showed ideal selectivity for the MSLN receptor (>100 nM against receptor negative PC3 cells). In animal-based experiments, A1-PE24X7 had tumor enrichment ability in relation to MSLN-positive tumors and showed strong tumor killing and inhibition in mouse models of pancreatic cancer and gastric cancer. Five injections of 3.0 mg/kg A1-PE24X7 significantly reduced the tumor volume of gastric NCI-N87 cancer and also significantly inhibited the growth of pancreatic AsPC-1 cancer. In addition, the maximum tolerable dosage (MSD) of A1-PE24X7 to mice was higher than 15 mg/kg, showing that A1-PE24X7 has a relatively broad therapeutic window. These preclinical results indicate that this strategy has good potential for application to the treatment of pancreatic cancer and other tumors with high MSLN expression.

PEG Linker Improves Antitumor Efficacy and Safety of Affibody-Based Drug Conjugates.

Antibody drug conjugates (ADCs) have become an important modality of clinical cancer treatment. However, traditional ADCs have some limitations, such as reduced permeability in solid tumors due to the high molecular weight of monoclonal antibodies, difficulty in preparation and heterogeneity of products due to the high drug/antibody ratio (4-8 small molecules per antibody). Miniaturized ADCs may be a potential solution, although their short circulation half-life may lead to new problems. In this study, we propose a novel design strategy for miniaturized ADCs in which drug molecules and small ligand proteins are site-specifically coupled via a bifunctional poly(ethylene glycol) (PEG) chain. The results showed that the inserted PEG chains significantly prolonged the circulation half-life but also obviously reduced the cytotoxicity of the conjugates. Compared with the conjugate ZHER2-SMCC-MMAE (HM), which has no PEG insertion, ZHER2-PEG4K-MMAE (HP4KM) and ZHER2-PEG10K-MMAE (HP10KM) with 4 or 10 kDa PEG insertions have 2.5- and 11.2-fold half-life extensions and 4.5- and 22-fold in vitro cytotoxicity reductions, respectively. The combined effect leads to HP10KM having the most ideal tumor therapeutic ability at the same dosages in the animal model, and its off-target toxicity was also reduced by more than 4 times compared with that of HM. These results may indicate that prolonging the half-life is very helpful in improving the therapeutic capacity of miniaturized ADCs. In the future, the design of better strategies that can prolong half-life without affecting cytotoxicity may be useful for further improving the therapeutic potential of these molecules.

HER2-specific immunotoxins constructed based on single-domain antibodies and the improved toxin PE24X7.

Human epidermal growth factor receptor 2 (HER2) is an attractive target for cancer therapy, although a large fraction of tumors that express HER2 may still resist first-line therapies. Immunotoxins with antibodies that are armed with extremely potent cytotoxic toxin molecules may provide an important solution to this problem. In this work, we constructed three new anti-HER2 immunotoxins by using single-domain antibody (sdAb) molecules as the targeting moiety and the improved toxin PE24X7 as the effector with the aim of simplifying the preparation and reducing the off-target toxicity of the immunotoxins. Due to the beneficial outcomes of sdAb molecules, the synthesized immunotoxins were efficiently expressed in soluble form, avoiding the refolding process required by the common immunotoxin design and having high solubility and stability. Cell toxicity experiments showed that they have high cytotoxicity against various HER2-positive tumor cells and good selectivity (more than 1000-fold) towards HER2-positive rather than HER2-negative cells. Importantly, in vivo treatment experiments showed that one of the new immunotoxins could efficiently halt tumor growth at doses lower than 0.75 mg/kg, and it had a maximum tolerated dose (MTD) higher than 8.0 mg/kg, showing a substantially improved MTD and a broadened therapeutic window than the previously reported anti-HER2 immunotoxins. Given that PE toxin-based immunotoxins have been approved for clinical cancer therapy, the unique characteristics of the immunotoxins presented here make them promising for use in the development of anti-HER2 cancer therapeutics.

Evaluating Estimates of Markov Models of Sequence Evolution through Simulation.

Current methods of evaluating techniques that estimate parameters of Markov models of sequence evolution require sequence data from populations with well-known phylogenetic relationships. Such data is not always available, since phylogenetic relationships can never be known with certainty. We propose generating sequence data for estimation technique evaluation by simulating sequence evolution in a controlled setting. Our elementary simulator assumes a Markov model and uses a binary branching process to dynamically build a phylogenetic tree from an initial seed sequence. We then observe how well estimation techniques recover the Markov model parameters specified in the simulation using the sequences at the leaves of the tree. We demonstrate our evaluation method on Arvestad and Bruno's estimation technique, and show how our approach can reveal performance variations.