Effects of climate change and anthropogenic activities on soil pH in grassland regions on the Tibetan Plateau

Although soil pH is an important indicator of soil quality, the effects of climate change and anthropogenic activities on soil pH remain controversial. Here, we quantified the potential soil pH at three depths (0–10, 10–20, and 20–30 cm) using annual temperature (AT), annual precipitation (AP) and annual radiation (ARad), and the actual soil pH at three depths using AT, AP, ARad and maximum normalized difference vegetation index based on random forest models over the grassland regions on the Tibetan Plateau in 2000–2020. Overall, climate change caused soil alkalinization at 0–10 cm, and soil acidification at 10–20 and 20–30 cm. Under climate change conditions, 36.84%, 29.87% and 23.71% regions showed soil alkalinization, whereas 45.52%, 44.49% and 21.43% regions showed soil acidification at 0–10, 10–20 and 20–30 cm, respectively. Climate change caused soil acidification in alpine meadows, but soil alkalinization in alpine steppes. The impacts of precipitation change on soil pH were not always greater than those of climate warming, depending on soil depth, and radiation change had some exclusive impacts on soil pH. Overall, anthropogenic activities caused soil alkalinization, but more than 1/10 regions showed soil acidification. Anthropogenic activities caused soil acidification in alpine meadows, but soil alkalinization in montane meadows at 10–20 cm. Therefore, the impacts of climate change and anthropogenic activities on soil pH did not always cause soil acidification or alkalization, but varied with grassland type and soil depth. Both climate change and anthropogenic activities reconstructed the spatial distribution pattern of soil pH. This study also cautioned that the impact of radiation change on soil pH should not be ignored

Modulation of Macrophages Using Nanoformulations with Curcumin to Treat Inflammatory Diseases: A Concise Review

International audienceCurcumin (Cur), a traditional Chinese medicine extracted from natural plant rhizomes, has become a candidate drug for the treatment of diseases due to its anti-inflammatory, anticancer, antioxidant, and antibacterial activities. However, the poor water solubility and low bioavailability of Cur limit its therapeutic effects for clinical applications. A variety of nanocarriers have been successfully developed to improve the water solubility, in vivo distribution, and pharmacokinetics of Cur, as well as to enhance the ability of Cur to polarize macrophages and relieve macrophage oxidative stress or anti-apoptosis, thus accelerating the therapeutic effects of Cur on inflammatory diseases. Herein, we review the design and development of diverse Cur nanoformulations in recent years and introduce the biomedical applications and potential therapeutic mechanisms of Cur nanoformulations in common inflammatory diseases, such as arthritis, neurodegenerative diseases, respiratory diseases, and ulcerative colitis, by regulating macrophage behaviors. Finally, the perspectives of the design and preparation of future nanocarriers aimed at efficiently exerting the biological activity of Cur are briefly discussed

Unsymmetrical Low-Generation Cationic Phosphorus Dendrimers as a Nonviral Vector to Deliver MicroRNA for Breast Cancer Therapy

International audienceThe development of nonviral dendritic polymers with a simple molecular backbone and great gene delivery efficiency to effectively tackle cancer remains a great challenge. Phosphorus dendrimers or dendrons are promising vectors due to their structural uniformity, rigid molecular backbones, and tunable surface functionalities. Here, we report the development of a new low-generation unsymmetrical cationic phosphorus dendrimer bearing 5 pyrrolidinium groups and one amino group as a nonviral gene delivery vector. The created AB5-type dendrimers with simple molecular backbone can compress microRNA-30d (miR-30d) to form polyplexes with desired hydrodynamic sizes and surface potentials and can effectively transfect miR-30d to cancer cells to suppress the glycolysis-associated SLC2A1 and HK1 expression, thus significantly inhibiting the migration and invasion of a murine breast cancer cell line in vitro and the corresponding subcutaneous tumor mouse model in vivo. Such unsymmetrical low-generation phosphorus dendrimers may be extended to deliver other genetic materials to tackle other diseases

Amphiphilic phosphorous dendron micelles co-deliver microRNA inhibitor and doxorubicin for augmented triple negative breast cancer therapy

International audienceCombined chemo/gene therapy of cancer through different action mechanisms has been emerging to enhance the therapeutic efficacy towards cancer, and still remains a challenging task due to the lack of highly effective and biocompatible nanocarriers. In this work, we report a new nanosystem based on amphiphilic phosphorus dendron (1-C12G1) micelles to co-deliver microRNA-21 inhibitor (miR-21i) and doxorubicin (DOX) for combination therapy of triple negative breast cancer. The amphiphilic phosphorus dendron bearing a long linear alkyl chain and ten protonated pyrrolidine surface groups was prepared and was demonstrated to form micelles in water solution and have a hydrodynamic size of 103.2 nm. The micelles are shown to be stable, enable encapsulation of an anticancer drug DOX with optimal loading content (80%) and encapsulation efficiency (98%), and can compress miR-21i to form polyplexes to render it with good stability against degradation. The co-delivery system of 1-C12G1@DOX/miR-21i polyplexes has a pH-dependent DOX release profile, and can be readily phagocytosed by cancer cells to inhibit them due to the different anticancer mechanisms, which was further validated after intravenous injection to treat an orthotopic triple-negative breast tumor model in vivo. With the proven biocompatibility under the studied doses, the developed amphiphilic phosphorus dendron micelles could be developed as an effective nanomedicine formulation for synergistic cancer therapy

Phosphorus dendron nanomicelles as a platform for combination anti-inflammatory and antioxidative therapy of acute lung injury

International audienceDevelopment of novel nanomedicines to inhibit pro-inflammatory cytokine expression and reactive oxygen species (ROS) generation for anti-inflammatory therapy of acute lung injury (ALI) remains challenging. Here, we present a new nanomedicine platform based on tyramine-bearing two dimethylphosphonate sodium salt (TBP)-modified amphiphilic phosphorus dendron (C11G3) nanomicelles encapsulated with antioxidant drug curcumin (Cur)

Bioactive Phosphorus Dendrimers as a Universal Protein Delivery System for Enhanced Anti-inflammation Therapy

Nanocarrier-based cytoplasmic protein delivery offers opportunities to develop protein therapeutics; however, many delivery systems are positively charged, causing severe toxic effects. For enhanced therapeutics, it is also of great importance to design nanocarriers with intrinsic bioactivity that can be integrated with protein drugs due to the limited bioactivity of proteins alone for disease treatment. We report here a protein delivery system based on anionic phosphite-terminated phosphorus dendrimers with intrinsic anti-inflammatory activity. A phosphorus dendrimer termed AK-137 with optimized anti-inflammatory activity was selected to complex proteins through various physical interactions. Model proteins such as bovine serum albumin, ribonuclease A, ovalbumin, and fibronectin (FN) can be transfected into cells to exert their respective functions, including cancer cell apoptosis, dendritic cell maturation, or macrophage immunomodulation. Particularly, the constructed AK-137@FN nanocomplexes display powerful therapeutic effects in acute lung injury and acute gout arthritis models by integrating the anti-inflammatory activity of both the carrier and protein. The developed anionic phosphite-terminated phosphorus dendrimers may be employed as a universal carrier for protein delivery and particularly utilized to deliver proteins and fight different inflammatory diseases with enhanced therapeutic efficacy