Altered metabolic profiles and biomarkers associated with astragaloside IV-mediated protection against cisplatin-induced acute kidney injury in rats: An HPLC-TOF/MS-based untargeted metabolomics study.

Cisplatin (CDDP)-induced acute kidney injury (AKI) limits the therapeutic use of CDDP, which urgently needs to be addressed. Our previous study demonstrated that astragaloside IV (AS IV), an active compound of the traditional Chinese herb Astragalus membranaceus, alleviated CDDP-induced AKI. To explore the mechanism, we performed a metabolomics study to explore the altered metabolic pathways and screen for sensitive biomarkers. Twenty-four rats were randomly divided into three groups, which were treated with vehicle solutions (Control), intraperitoneally injected CDDP, and intraperitoneally injected CDDP plus oral AS IV, respectively. Metabolic profiles of serum, urine, and kidney samples were analyzed by high-performance liquid chromatography-time of flight mass spectrometry. There were 38 key metabolites in the urine samples, 20 in the serum samples, and 16 in the kidney samples that were significantly altered due to AS IV-mediated protection against CDDP-induced AKI relative to CDDP-only treatment. CDDP + AS IV co-treatment significantly altered two pathways in the blood (biosynthesis of unsaturated fatty acids and alanine, aspartate, and glutamate metabolism), five pathways in the urine (phenylalanine metabolism; phenylalanine, tyrosine, and tryptophan biosynthesis; arginine biosynthesis; arginine and proline metabolism; and histidine metabolism), and five pathways in the kidneys (glutathione metabolism; alanine, aspartate, and glutamate metabolism; glyoxylate and dicarboxylate metabolism; arginine and proline metabolism; and D-glutamine and D-glutamate metabolism). The metabolic pathways were mainly associated with improvements in inflammatory responses, oxidative stress, and energy metabolism. Adrenic acid in serum and L-histidine and L-methionine in urine were identified as sensitive biomarkers. This study provides new insights to understand the mechanism of AS IV-mediated protection against CDDP-induced AKI and has identified three candidate biomarkers to evaluate preventative treatment and assess therapeutic effectiveness.

Developing ICP-MS/MS for the detection and determination of synthetic DNA-protein crosslink models via phosphorus and sulfur detection.

Various endogenous and exogenous agents drive the un-directed formation of covalent bonds between proteins and DNA. These complex molecules are of great biological relevance, as can derive in mutations, but are difficult to study because of their heterogeneous chemical properties. New analytical approaches with sufficient detection capabilities to detect and quantify these compounds can help to standardize study models based on synthesized standards. The use of atomic spectrometry can provide quantitative information on the DNA-protein cross-link reaction yield along with basic stoichiometry of the products, based on internal elemental tags, sulfur from Cys and Met amino acids, and phosphorus from the DNA. A new instrumental approach to remove isobaric and polyatomic interferences from (31)P(+) and (32)S(+) was developed recently, with state-of-the-art for interference removal that captures (31)P(+) in Q1; it reacts with O2 in an octopole collision-reaction cell generating (47)PO(+), therefore allowing detection in Q3 without (31)NOH(+)/(48)Ca/(47)Ti interferences. Similarly, (32)S(+) is reacted to (48)SO(+), eliminating the polyatomic interferences at m/z = 32. In conjunction with the high resolving power of high-performance liquid chromatography (HPLC), this newer technology was applied by to the product purification of a DNA-protein cross link model and some preliminary structural studies.

Pd nanosheet-covered hollow mesoporous silica nanoparticles as a platform for the chemo-photothermal treatment of cancer cells.

A versatile system combining chemotherapy with photothermal therapy for cancer cells using Pd nanosheet-covered hollow mesoporous silica nanoparticles is reported. While the hollow mesoporous silica core can be used to load anticancer drugs (i.e., doxorubicin) for chemotherapy, the Pd nanosheets on the surface of particles can convert NIR light into heat for photothermal therapy. More importantly, the loading of Pd nanosheets on hollow mesoporous silica nanospheres can dramatically increase the amount of cellular internalization of the Pd nanosheets: almost 11 times higher than the unloaded Pd nanosheets. The as-prepared nanocomposites efficiently deliver both drugs and heat to cancer cells to improve the therapeutic efficiency with minimal side effects. Compared with chemotherapy or photothermal therapy alone, the combination of chemotherapy and phototherapy can significantly improve the therapeutic efficacy, exhibiting a synergistic effect.

Identification of beta-lactamase inhibitory peptide using yeast two-hybrid system.

Random oligonucleotide fragments were designed and amplified by PCR and fused with the activating domain of pGAD424 to construct a random peptide library. The DNA fragment encoding beta-lactamase was fused with the binding domain of pGBT9(+2). Subsequently, using yeast two-hybrid system we found two positive clones encoding peptides P1 and P2 that have the ability to bind beta-lactamase in vivo. The genes encoding P1 and P2 were cloned into pGEX-4T-1. GST-peptide fusion proteins were expressed in Escherichia coli and isolated by glutathione-Sepharose 4B affinity chromatography. Finally, P1 and P2 were cleaved from the fusion protein with thrombin and purified by ultrafiltration. Inhibition assay of peptides with beta-lactamase in vitro indicated that only P1 has the ability to inhibit beta-lactamase.