Latest ArticlesLefamulin (BC-3781) is a semi-synthetic pleuromutilin antibiotic, approved for the treatment of community-acquired bacterial pneumonia (CABP) by Food and Drug Administration (USA) in August 2019, with the commodity name of Xenleta. It is the first pleuromutilin antibiotics used for systemic treatment of bacterial infections in human. Lefamulin binds to the peptidyl transferase center of the 50S ribosomal subunit to prevent peptide transfer, thus inhibits protein synthesis. Lefamulin displays expanded activity against gram-positive organisms, and also shows high activity against atypical microorganism like Mycoplasma pneumoniae. This review discusses the mechanism, bacterial spectrum of activity, preclinical and clinical data of Lefamulin.
Tumor microenvironment (TME) is a complex comprehensive system composed of immune cells, inflammatory cells, tumor-associated fibroblasts, microvessels, and various cytokines and chemokines. As the living environment of tumor cells, it's closely related to the occurrence, metastasis, and recurrence of tumors. The characteristics of tumor microenvironment include: weakly acidic environment, low oxygen, high concentration of reactive oxygen species (ROS) and reducing substances, immunosuppression, etc. A weakly acidic environment favors metastasis of tumor cells, hypoxia is conducive to the emergence of drug resistance, high concentration of ROS and reducing substances are beneficial for tumor treatment, and immunosuppressiveness facilitates immune escape. With the rapid development of nanotechnology, more and more nanostructures have been reported to achieve tumor treatment by regulating the tumor microenvironment. This review summarizes recent advances in the nanostructures used to regulate tumor microenvironment through changing elements, including hydrogen-ion concentration (pH), the concentration of oxygen (O2) and reactive oxygen species, and the activity of immune cells. Moreover, research directions in the future are pointed out in this review.
In the past few decades, our understanding of platelets has made great progress. Platelets play an unexpected central role in cancer and greatly affect the behavior of cancer cells. At the same time, the physiology and phenotype of platelets are also affected by cancer cells. Therefore, platelet-based tumor targeted therapy strategies have attracted the attention of researchers, but the limitations of their application require more attention. In this paper, the strategies of platelet-based tumor targeted therapy are summarized, and the strategies of platelet mimicking nanocarrier delivery, platelet hitch riding, platelet membrane coating biomimetic and engineered platelet targeting are mainly introduced. The easy activation, hard storage and unknown functional and phenotypic changes of platelets were discussed. At the same time, the strategy of platelet-based targeted tumor therapy is reviewed from theoretical basis and practical application. The development potential of platelets in the field of tumor diagnosis and treatment is discussed, which will provide some theoretical reference for the study of platelet-related tumor diagnosis and targeted therapy.
To study the regulating effect of total phenolic acids from the stems and leaves of Salvia miltiorrhiza Bge. on the intestinal flora and short-chain fatty acids in spontaneous type 2 diabetic nephropathy mice, db/db mice were taken as the research object, and were treated with the total phenolic acid of Salvia miltiorrhiza Bge. Animal welfare and experimental procedures followed the regulations of the Animal Ethics Committee of Nanjing University of Chinese Medicine Drug Safety Evaluation Research Center. Fresh feces and cecal contents of mice were collected for analysis of intestinal flora composition and differential flora. Gas chromatography was used to detect short-chain fatty acids in fresh feces and cecal content. Then the correlation analysis of the two results was made. Compared with the normal group, the most significant decreased differential flora in the model group were g_Rikenellaceae_RC9_gut_group and g_Bacteroidales_S24-7_group, while the most significant increased were g_unclassified_f__Coriobacteriaceae and g_unclassified_p__Firmicutes. Compared with the blank group, the contents of isovaleric acid and valeric acid in fresh feces and the contents of 6 short-chain fatty acids in the cecal contents of the model group were significantly reduced (P < 0.01). After drug intervention, the intestinal flora disorder and the reduction of short-chain fatty acids were improved to varying degrees, and the effect of the total phenolic acids from the stems and leaves of Salvia miltiorrhiza Bge. was slightly better than that from the roots in regulating some flora and short-chain fatty acids. The results of correlation analysis showed that g_Rikenellaceae_RC9_gut_group was moderately positively correlated with acetic acid and isobutyric acid in the cecal contents (r > 0.4). It is suggested that the total phenolic acid from the stems and leaves of Salvia miltiorrhiza Bge. can improve the intestinal flora disorder of mice with type 2 diabetic nephropathy, and can regulate the content of short-chain fatty acids in the intestine via adjusting the content of some short-chain fatty acid-producing bacteria, thereby helping to restore normal.
Insulin resistance refers to the impaired ability of insulin to regulate glucose metabolism in peripheral organs, which is considered to be the etiology of type 2 diabetes. This study aims to explore the mechanism of improving insulin resistance by compatibility of Salviae Miltiorrhizae Radix et Rhizoma and Carthami Flos (DH). Insulin resistance was conducted on C56BL/6J mice by treatment of high fat diet. The energy intake and body weight, plasma levels of triglycerides, total cholesterol, insulin and glucose, oral glucose tolerance test (OGTT) and insulin tolerance test (ITT), as well as gene transcription and protein expression levels of insulin signaling pathway in liver, heart, kidney, and skeletal muscle of insulin resistance mice were evaluated. Animal experiments and welfare were performed in compliance with the guidelines of Animal Ethics Committee of Nanjing University of Chinese Medicine. The results showed that DH treatment significantly alleviated the excessive food intake and weight gain, and significantly decreased the levels of plasma triglycerides and total cholesterol, and constantly mitigated the hyperinsulinemia in insulin resistance mice. The results of OGTT and ITT suggested that DH treatment dramatically improved the response of insulin resistance mice to insulin stimulated glucose metabolism. Furthermore, the imbalance of metabolic arm and mitogenic arm of insulin signaling pathway in insulin resistance mice was normalized after DH treatment. DH treatment regulated insulin signaling pathway and improved the ability of glucose metabolism of insulin resistance mice.
This study investigated the effects of ginkgolide B on the long-chain fatty acid metabolism-related enzyme protein peroxisome proliferators-activated receptors α (PPARα), long-chain specific acyl-CoA dehydrogenase (LCAD), carnitine palmitoyl transterase-1 (CPT-1), and acyl coenzyme A oxidase 1 (ACOX1) expression in the liver of rats with non-alcoholic fatty liver disease (NAFLD). All the animal welfare and experimental procedures are in accordance with the regulations of the Animal Ethics Committee of Yunnan University of Traditional Chinese Medicine. After successfully building the rat model of non-alcoholic abnormal liver disease, the rats were divided into the model group, the simvastatin group, and the low-dose, middle-dose, and high-dose groups of ginkgolide B according to random number method, and were given corresponding drug treatment 4 weeks. We detected liver pathological indicators and determined blood lipids, transaminase and anti-oxidation indexes. Western blot and RT-PCR assays were used to detect the protein and mRNA levels of PPARα, LCAD, CPT-1, and ACOX1 in livers. The results showed that: ① the liver histopathology showed that the liver slices of the model group had obvious structural disorder, the nucleus was squeezed, and there were obvious fat vacuoles. The treatment groups improved significantly compared with the model group; ② compared with the normal group, the liver function and blood lipid indexes of the model group increased significantly, while the anti-oxidation indexes decreased significantly. Compared with the model group, each treatment groups were significantly improved; ③ compared with the normal group, the protein and mRNA expression levels of PPARα, ACOX1, CPT-1, and LCAD in the model group were significantly reduced, compared with the model group, those indexes in the treatment groups were significantly up-regulated. This study found that ginkgolide B could regulate the expression of long-chain fatty acid metabolism-related proteins PPARα, ACOX1, CPT-1, and LCAD, meanwhile improve the body's antioxidant capacity, thereby reduce blood lipids, further improve liver function and protect the liver.
Abnormal aggregation of amyloid-β protein (Aβ) in brain plays a vital role in the occurrence of Alzheimer's disease (AD). Hence, inhibiting Aβ aggregation is one major tactic for therapy of AD. Previous studies have found that tolcapone can inhibit Aβ42 aggregation and reduce the cytotoxicity induced by Aβ42 aggregates, but clinical studies have found that tolcapone has strong liver toxicity. To reduce the liver toxicity of tolcapone, its side chain structure was modified to obtain its derivative phenethyl (E)-2-cyano-3-(3, 4 dihydroxy-5-nitrobenzene)-acrylate (PCDNA). Thioflavin T (ThT) and atomic force microscopy (AFM) assays were used to explore the inhibitory effect of PCDNA on Aβ42 fibrillogenesis. The cytotoxicity assays were used to explore the inhibitory effect of PCDNA against the cytotoxicity induced by Aβ42 aggregates. In addition, the depolymerization effect of PCDNA on mature Aβ42 fibrils was also explored. Finally, molecular docking was used to explore the interaction between PCDNA and Aβ42 pentamer. These results lay the foundation for the study of the structural analogues of tolcapone as Aβ inhibitors.
Z-VAD-FMK was combined with hypoxia-reoxygenation (H/R) injury to establish a necroptosis model of H9c2 cells to mimic the pathological changes of myocardial ischemia reperfusion injury (MIRI) in vitro and to study the effect and mechanism of tilianin against myocardial ischemia-reperfusion injury. A cell counting kit-8 (CCK-8) was used to detect cell viability, and commercial kits were used to detect lactate dehydrogenase (LDH) and superoxide dismutase (SOD) in the cell culture supernatant. Hoechst 33342/PI immunofluorescence staining was used to detect cell death. DCFH-DA, BBcellProbeTMM61, and JC-1 probes were used to detect reactive oxygen species (ROS), mitochondrial permeability transition pore (mPTP), and mitochondrial membrane potential (MMP), respectively. An enzyme-linked immunosorbent assay (ELISA) method was used to detect the release of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). The results show that the cell viability, SOD activity, and MMP of the model group induced by H/R injury decreased, as compared with control group, but the necroptosis rate, LDH level, and ROS release increased significantly. Furthermore, mPTP of the model group cells opened, and TNF-α, IL-1β, and IL-6 levels were significantly higher. Molecular docking modeling showed that tilianin can bind to calmodulin-dependent protein kinase Ⅱ (CaMKII), and Western blot results showed that compared with control group, the expression levels of p-CaMKII and phospho-mixed lineage kinase domain-like protein increased in the model group, and tilianin could decrease the expression level of these proteins. The above results indicate that tilianin can protect H9c2 cells by inhibiting the phosphorylation of CaMKII at threonine 287, protecting mitochondrial function, and inhibiting the opening of mPTP to prevent necroptosis. This study has value for research on new methods to treat H/R injury.
In recent years, there has been an increase in the incidence of herbal-induced liver injury due to the accidental ingestion of herbal medicines containing pyrrolizidine alkaloids (PAs) in domestic. Salvianolic acid B (Sal B), a hydrophilic component in Salvia miltiorrhiza Bge., shows activities of anticoagulation, antioxidation, and other pharmacological activities. This research aims to investigate the protective effect of Sal B on hepatotoxicity induced by senecionine (SEN) and its potential mechanism. The animal experiment was approved by the Experimental Animal Ethical Committee of Shanghai University of Traditional Chinese Medicine, and all mice have received humane care in compliance with the institutional animal care guidelines. Mice were treated with Sal B (10 mg·kg-1) 3 days before and 1 day after SEN (50 mg·kg-1) treatment. The animals were sacrificed 48 h after SEN administration. As a result, Sal B effectively ameliorated SEN-induced liver injury. The mice in the group treated with Sal B showed lower serum activities of alanine aminotransferase and aspartate aminotransferase, less hepatic sinusoidal hemorrhage, and reduced hepatocyte necrosis. Besides, contents of pyrrole-protein adducts, the marker for PA-induced toxicity, were also decreased in serum. The key factors related to coagulation, oxidative stress, and liver fibrosis were further analyzed. It was found that Sal B inhibited the coagulant system by reducing the expression of plasminogen activator inhibitor-1. Sal B also modulated glutathione and superoxide dismutase levels and improved the anti-oxidative defense system. In addition, Sal B decreased the excessive deposition of extracellular matrix and inhibited the progression of liver fibrosis via down-regulating several key factors related to liver fibrosis, including matrix metalloproteinase 9, transforming growth factor-β1, signal transducer and activator of transcription 3, and chemokine 1. In conclusion, Sal B ameliorated SEN-induced liver injury in mice by regulating the blood coagulation system, improving oxidative stress, and modulating liver fibrosis-related factors. Our present study pointed to the possibility of utilizing salvianolic acid B for protection against PA-induced liver injury clinically.
Bioorthogonal fluorogenic probes are becoming an ideal tool for live-cell fluorescence imaging. With the tetrazine bioorthogonal fluorogenic probe that displays fluorescence enhancement, the tetrazine plays the dual-role of a bioorthogonal reaction unit and the fluorescence quenching unit. The "off" and "on" states of the fluorescence probe are mainly controlled through inverse electron demand Diels-Alder (IEDDA) bioorthogonal reaction. We designed a series of turn-on tetrazine fluorescent probes with Donor-π-Acceptor (D-π-A) structure to achieve a high signal-to-noise ratio and specificity of fluorescence imaging. This series of probes reacted with the dienophile bicyclononyne, and then generated pyridazine structure in-situ that acted as an electron acceptor, resulting in a new D-π-A effect of fluorescent dyes, turning on the intramolecular charge transfer (ICT) effect. By adjusting the electron-donating groups and the degree of conjugation, tunable fluorescence spectra between 400-647 nm with fluorescence turn-on enhanced up to 500-fold have been achieved. This research lays the foundation for the further optimization of tetrazine bioorthogonal fluorescent probes and their applications in molecular imaging and biomedical fields.