INOS-mediated acute stomach injury and recovery in mice after oral exposure to halloysite nanotubes

Effects of multi-walled carbon nanotubes and halloysite nanotubes on plasma lipid profiles and autophagic lipolysis pathways in mouse aortas and hearts

Multi-walled carbon nanotubes (MWCNTs) and halloysite nanotubes (HNTs) are widely used tubular-structured nanomaterials (NMs), but their cardiovascular effects are not clear. This study compared the effects of MWCNTs and HNTs on lipid profiles in mouse plasma and gene expression profiles in aortas and hearts. Mice were intravenously injected with 50 μg NMs, once a day, for 5 days. Then, the plasma was collected for lipidomics analysis, and aortas and hearts were collected for RNA-sequencing analysis. While MWCNTs or HNTs did not induce obvious pathological changes in aortas or hearts, the lipid profiles in mouse plasma were altered. Further analysis revealed that MWCNTs more effectively upregulated sphingolipids and sterol lipids, whereas HNTs more effectively upregulated glycerophospholipids and fatty acyls. Consistently, RNA-sequencing data indicated that MWCNTs and HNTs altered signaling pathways related with lipid synthesis and metabolism, as well as those related with endoplasmic reticulum, lysosomes and autophagy, more significantly in aortas than in hearts. We further verified the changes of proteins involved in autophagic lipolysis, that MWCNTs were more effectively to suppress the autophagic biomarker LC3, whereas HNTs were more effectively to affect lipid metabolism proteins. These results may provide novel understanding about the influences of MWCNTs and HNTs on lipid profiles and lipid signaling pathways in cardiovascular systems. Importantly, previous studies considered HNTs as biocompatible materials, but the results from this study suggested that both MWCNTs and HNTs were capable to affect lipid profiles and autophagic lipolysis pathways in cardiovascular systems, although their exact influences were different.

Recent advances in natural nanoclay for diagnosis and therapy of cancer: A review

Cancer is still one of the deadliest diseases, and diagnosing and treating it effectively remains difficult. As a result, advancements in earlier detection and better therapies are urgently needed. Conventional chemotherapy induces chemoresistance, has non-specific toxicity, and has a meager efficacy. Natural materials like nanosized clay mineral formations of various shapes (platy, tubular, spherical, and fibrous) with tunable physicochemical, morphological, and structural features serve as potential templates for these. As multifunctional biocompatible nanocarriers with numerous applications in cancer research, diagnosis, and therapy, their submicron size, individual morphology, high specific surface area, enhanced adsorption ability, cation exchange capacity, and multilayered organization of 0.7-1 nm thick single sheets have attracted significant interest. Kaolinite, halloysite, montmorillonite, laponite, bentonite, sepiolite, palygorskite, and allophane are the most typical nanoclay minerals explored for cancer. These multilayered minerals can function as nanocarriers to effectively carry a variety of anticancer medications to the tumor site and improve their stability, dispersibility, sustained release, and transport. Proteins and DNA/RNA can be transported using nanoclays with positive and negative surfaces. The platform for phototherapeutic agents can be nanoclays. Clays with bio-functionality have been developed using various surface engineering techniques, which could help treat cancer. The promise of nanoclays as distinctive crystalline materials with applications in cancer research, diagnostics, and therapy are examined in this review.

Effects of nano-cerium dioxide on intestinal microflora in rats by oral subchronic exposure

OBJECTIVE

To investigate intestinal toxicity in rats and the effects of Nano-cerium dioxide on intestinal flora in rats after oral sub-chronic exposure.

METHOD

Forty healthy male SD rats were randomly divided into four groups: a control group (deionized water) and three groups treated with different doses of Nano-ceria (e.g., 20 mg/kg, 100 mg/kg, and 500 mg/kg), with 10 rats in each group. The rats were given intragastric administrations (every other day) for 90 days. After the last intragastric administration, fresh fecal samples were collected by pressing the abdomen, and the animals were sacrificed. Jejunum, ileum and cecum tissues were retained for pathological analysis by Hematoxylin-eosin staining. The stool samples of rats were sequenced by the Illumina NovaSeq sequencing platform, and the sequencing results were further analyzed by QIIME2 software.

RESULTS

The histopathology results show that compared with the control group, in the middle- and high-dose groups, epithelial tissue was shed, lamina propria glandular structures were damaged or disappeared, and large numbers of inflammatory cells were distributed in the mucosa. The intestinal flora results show that there were no significant differences in the α-/β-diversities in each Nano-ceria-treated group compared with the control group (P>0.05). Compared with the control group, the intestinal pathogenic bacteria, Mucispirillum and Streptococcus increased significantly after Nano-cerium dioxide ingestion, while Weissella decreased. The abundances of Akkermansia in all Nano-ceria-treated groups were higher than those in the control group, but the abundances decreased with increasing dose. MetagenomesSeq analysis show that, compared with the control group, the abundances of S24-7, Lactobacillus and Clostridiales in all experimental groups significantly decreased.

CONCLUSIONS

The sub-chronic toxicity of Nano-cerium dioxide to rats can affect the structure and abundance of intestinal microflora, long-term exposure to high doses (>100 mg/kg) causes enteritis, but there was no significant difference in the diversity of gut microbiota. Therefore, we infer that the enteritis in rats may be associated with the relative ratios of the pathogenic bacteria and intestinal probiotics, and increased of the intestinal pathogenic bacteria can disrupted intestinal homeostasis.

Protective effect of Amauroderma rugosum ethanol extract and its primary bioactive compound, ergosterol, against acute gastric ulcers based on LXR-mediated gastric mucus secretions

BACKGROUND

Amauroderma rugosum (Blume & T. Nees) Torrend (Ganodermataceae) is an edible mushroom with a wide range of medicinal values. Our previous publication demonstrated the therapeutic effects of the water extract of A. rugosum (WEA) against gastric ulcers. However, the protective effects of the ethanol extract of A. rugosum (EEA) on gastric mucosa and its major active constituents have not yet been elucidated.

PURPOSE

This study aims to evaluate the gastroprotective effects and underlying mechanisms of EEA and its fat-soluble constituent, ergosterol, in acute gastric ulcers.

STUDY DESIGN AND METHOD

SD rats were pre-treated with EEA (50, 100, and 200 mg/kg) or ergosterol (5, 10, and 20 mg/kg), and acute gastric ulcer models were constructed using ethanol, gastric mucus secretion inhibitor (indomethacin) or pyloric-ligation. The gastric ulcer area, histological structure alterations (H&E staining), and mucus secretion (AB-PAS staining) were recorded. Additionally, Q-PCR, western blotting, immunohistochemistry, ELISA, molecular docking, molecular dynamics simulations, MM-GBSA analysis, and surface plasmon resonance assay (SPR) were used to investigate the underlying mechanisms of the gastroprotective effect.

RESULT

Compared with WEA, which primarily exerts its anti-ulcer effects by inhibiting inflammation, EEA containing fat-soluble molecules showed more potent gastroprotective effect through the promotion of gastric mucus secretion, as the anti-ulcer activity was partly blocked by indomethacin. Meanwhile, EEA exhibited anti-inflammatory effects by suppressing the production of IL-6, IL-1β, TNF-α, and NO, thereby inhibiting the MAPK pathway. Significantly, ergosterol (20 mg/kg), the bioactive water-insoluble compound in EEA, exhibited a gastroprotective effect comparable to that of lansoprazole (30 mg/kg). The promotion of gastric mucus secretion contributed to the effects of ergosterol, as indomethacin can completely block it. The upregulations of COX1-PGE2 and C-fos, an activator protein 1 (AP-1) transcription factor, were observed after the ergosterol treatment. Ergosterol acted as an LXRβ agonist via van der Waals binding and stabilizing the LXRβ protein without compromising its flexibility, thereby inducing the upregulation of AP-1 and COX-1.

CONCLUSION

EEA and its primary bioactive compound, ergosterol, exert anti-ulcer effects by promoting gastric mucus secretion through the LXRβ/C-fos/COX-1/PGE2 pathway.

Preclinical developments of natural-occurring halloysite clay nanotubes in cancer therapeutics

The natural world holds useful resources that can be exploited to design effective therapeutic approaches. Ready-to-use tubular nanoclays, such as halloysite clay nanotubes (HNTs), are widely available, cost-effective, and sustainable submicron crystalline materials that have been showing great potential towards chronic multifactorial and malignant diseases, standing out as a promising anticancer nanotherapeutic strategy. Currently, several preclinical studies have reported the application of HNTs in cancer research, diagnosis, monitoring, and therapeutics. This groundbreaking review highlights the preclinical knowledge hitherto collected concerning the application of HNTs towards cancer therapy. Despite their reproducibility issues, HNTs were used as nanoarchitectonic platforms for the delivery of conventional chemotherapeutic, natural-occurring, biopharmaceutical, and phototherapeutic anticancer agents in a wide range of in vitro and in vivo solid cancer models. Overall, in different types of cancer mice models, the intratumoral and intravenous administration of HNTs-based nanoplatforms induced tumor growth inhibition without causing significant toxic effects. Such evidence raises a relevant question: does the therapeutic benefit of the parenteral administration of HNTs in cancer outweigh their potential toxicological risk? To answer this question further long-term absorption-distribution-metabolism-excretion studies in healthy and cancer animal models need to be performed. In cancer therapeutics, HNTs are envisaged as promising platforms for cancer multi-agent therapy, enabling the combination of different therapeutic modalities. Furthermore, HNTs might constitute suitable nanotheranostic platforms. Nevertheless, to confirm the potential and safety of the application of HNTs as nanodelivery systems for cancer therapy, it is necessary to perform in-depth in vivo pharmacokinetics and pharmacodynamic studies to further the translation to clinical trials.

Sierra Nevada sweep: metagenomic measurements of bioaerosols vertically distributed across the troposphere

To explore how airborne microbial patterns change with height above the Earth’s surface, we flew NASA’s C-20A aircraft on two consecutive days in June 2018 along identical flight paths over the US Sierra Nevada mountain range at four different altitudes ranging from 10,000 ft to 40,000 ft. Bioaerosols were analyzed by metagenomic DNA sequencing and traditional culturing methods to characterize the composition and diversity of atmospheric samples compared to experimental controls. The relative abundance of taxa changed significantly at each altitude sampled, and the diversity profile shifted across the two sampling days, revealing a regional atmospheric microbiome that is dynamically changing. The most proportionally abundant microbial genera were Mycobacterium and Achromobacter at 10,000 ft; Stenotrophomonas and Achromobacter at 20,000 ft; Delftia and Pseudoperonospora at 30,000 ft; and Alcaligenes and Penicillium at 40,000 ft. Culture-based detections also identified viable Bacillus zhangzhouensis, Bacillus pumilus, and Bacillus spp. in the upper troposphere. To estimate bioaerosol dispersal, we developed a human exposure likelihood model (7-day forecast) using general aerosol characteristics and measured meteorological conditions. By coupling metagenomics to a predictive atmospheric model, we aim to set the stage for field campaigns that monitor global bioaerosol emissions and impacts.