Current advances of CRISPR/Cas system in antibacterial field / 药学学报

A breakthrough in molecular biology for the twenty-first century is CRISPR/Cas gene editing, which has been used in a variety of fields due to its simplicity, adaptability, and targeting. Given the current global challenge of severe bacterial resistance, difficulties in detecting antimicrobial resistance, and slow development of antimicrobial drugs, CRISPR/Cas gene-editing technology offers a promising avenue for the development of antibacterial treatments. On the one hand, CRISPR/Cas gene editing technology helps advance the study of bacterial functions and serves as a toolbox. For instance, Cas proteins and exogenous repair systems enable efficient and precise gene editing, nCas proteins and deaminase systems facilitate template-free and single base precision editing, dCas proteins and reverse transcriptase allow for repair-free gene editing, and dCas proteins and modified sgRNA enable gene expression level regulation and gene function analysis. On the other hand, its specific gene recognition and targeted DNA cleavage characteristics can be used for pathogen detection, elimination of drug-resistant bacteria and genes, and hold promise as a new strategy for clinical diagnosis and treatment.

Construction and identification of recombinant adenovirus expressing S protein receptor binding domain and N protein of SARS-CoV-2 Delta variant / 中国生物制品学杂志

@#ObjectiveTo construct and identify a recombinant adenovirus expressing S protein receptor binding domain(RBD)and N protein of severe acute respiratory symptom coronavirus 2(SARS-CoV-2)Delta variant.MethodsThe RBD and N gene fragments of SARS-CoV-2 were cloned into pcDNA3.0BA vector respectively to construct recombinant plasmid pcDNA3.0BA-RBD-N. The RBD-CMV-N fragment was amplified by PCR and inserted into shuttle vector pShuttle-CMV. The shuttle plasmid pShuttle-RBD-N was then homologously recombined with pAdeasy-1 to obtain recombinant plasmid pAdeasy-1-RBD-N,which was transfected into HEK293 cells for recombinant adenovirus Ad-RBD-N packaging. The transcription of RBD and N genes of recombinant adenovirus in HEK293 cells was detected by RT-PCR,while the expre-ssion of RBD and N proteins by Western blot and immunofluorescence assay. 12 female BALB/c mice were immunized with Ad-RBD-N by intramuscular injection at a dose of 5 × 109copies per mouse. Blood samples were collected 14 d after immunization,and the serum antibody titers were measured by ELISA.ResultsThe RBD and N genes of recombinant adenovirus were transcribed normally in HEK293 cells,and the RBD and N proteins were expressed normally in MA104 cells. Mice immunized with the recombinant adenovirus produced specific IgG antibodies against RBD and N proteins.ConclusionThe recombinant adenovirus expressing S protein RBD and N protein of SARS-CoV-2 Delta variant was succe-ssfully constructed,which laid a foundation of the follow-up research on Delta variant vaccines.

Cardiovascular Protective Effect of Shenmai Injection： A Review / 中国实验方剂学杂志

With the improvement of people's living standards and the increasing aging population， the incidence of cardiovascular diseases has sharply risen， making it the leading cause of death and a major "killer" for humans. The prevention and treatment of cardiovascular diseases still face severe challenges. Shenmai injection （SMI）， a Chinese medicinal preparation， is widely used in the prevention and treatment of cardiovascular diseases because of its individualized advantages in syndrome differentiation and definite efficacy. Meanwhile， its pharmacological effects and related mechanism are becoming increasingly clear. Modern research shows that SMI can exert cardioprotective effects by reducing myocardial inflammatory response， alleviating oxidative stress， inhibiting myocardial cell apoptosis， improving microcirculatory dysfunction after myocardial ischemia-reperfusion， protecting mitochondrial structure and function， inhibiting ventricular remodeling， reducing drug-induced cardiotoxicity， and possessing antiviral properties. Additionally， it can produce cardiovascular protection by relaxing blood vessels， protecting endothelial cells， and promoting angiogenesis. Furthermore， SMI can lower blood viscosity and lipid levels， thus improving blood rheology. In the future， more clinical trials and basic research are needed to clarify its therapeutic efficacy and target mechanism to further confirm the effectiveness and safety of its clinical application.

Two Serum Free Light Chain Detection Systems in the Diagnosis of Multiple Myeloma / 中国实验血液学杂志

OBJECTIVE@#To investigate the comparability of the Freelite, Binding Site, Beckman and N Latex FLC, Siemens in the detection of serum free light chain (sFLC) .@*METHODS@#Fifty newly diagnosed multiple myeloma (MM) patients in Tianjin Institute of Blood Research from November 2019 to February 2020 were enrolled. The two systems (Freelite, Binding Site, Beckman and N Latex FLC, Siemens) were used to detect the sFLC of the samples. Outlier detection was performed by ESD method, methodological comparison and deviation assessment were performed by Passing-Bablok regression and Bland-Altman regression.@*RESULTS@#Both the systems could quantitatively analyze free kappa light chain serum samples and free lambda light chain samples. Freelite, Binding Site, Beckman and N Latex FLC, Siemens free light chain test showed FLC-κ：36.5 (6.5, 194), 40.5 (6.94, 288), FLC-λ: 30.1 (4.3, 170.5), 35.1 (2.28, 526), rFLC (FLC-κ/ FLC-λ) : 0.82 (0.05, 43.25), 1.03 (0.03, 32.04), dFLC (｜FLC-κ- FLC-λ｜) : -5.8 (-161.97, 183.7), 1.1 (-505.1, 279.01), which existed no outliers. There were systematic differences, and the deviation level was not within the clinically acceptable range.@*CONCLUSION@#Both the systems can meet the needs of clinical diagnosis and treatment, but there is a significant deviation between the two systems, the results are not comparable, and should be analyzed separately. In particular, the same system should be selected for monitoring the prognosis of MM.

Assessment of Benchmark Dose in BEAS-2B Cells by Evaluating the Cell Relative Viability with Particulates in Motorcycle Exhaust / 生物医学与环境科学（英文）

Objective@#This study aimed to use an air-liquid interface (ALI) exposure system to simulate the inhalation exposure of motorcycle exhaust particulates (MEPs) and then investigate the benchmark dose (BMD) of MEPs by evaluating cell relative viability (CRV) in lung epithelial BEAS-2B cells.@*Methods@#The MEPs dose was characterized by measuring the number concentration (NC), surface area concentration (SAC), and mass concentration (MC). BEAS-2B cells were exposed to MEPs at different concentrations @*Results@#Our results reveal that BMD of NC and SAC were estimated by the best-fitting Hill model, while MC was estimated by Polynomial model. The BMDL for CRV following ALI exposure to MEPs were as follows: 364.2#/cm @*Conclusion@#These results indicate that MEPs exposure

Research progress in drugs for treating sepsis / 药学学报

Sepsis is a refractory disease with high mortality in which the host's immune response to the infection is dysfunctional, resulting in life-threatening organ function damage. The pathogenesis of sepsis is complex, involving systemic inflammation, immunosuppressive and coagulation abnormalities, and endothelial barrier damage caused by the infecting pathogenic microorganisms and their toxins. The pathogenesis of sepsis is closely related to multiple systems disorder and multiple organ dysfunction and failure. In recent years, the incidence of sepsis has been increasing globally, with an annual increase of 9%. Since the development of sepsis does not depend on the infecting pathogenic microorganisms and the late inflammatory reaction can be life-threatening, clinical treatment of sepsis can be very difficult. However, the current antibiotic treatments for sepsis are not ideal. Most clinical treatments are not curative, so researchers seek new drug designs based on exploring molecular mechanisms of the pathophysiological process in sepsis patients. This paper reviews the recent development of drugs designed according to the sepsis pathophysiological process.

Research progress on the relationship between Vitamin D deficiency and neonatal lung development / 中华实用儿科临床杂志

Vitamin D deficiency is common among pregnant women and newborns, and Vitamin D plays an important role in the neonatal lung development.Animal experiments proved that Vitamin D has a significant effect on type Ⅱ alveolar cell proliferation, fibroblast proliferation, surfactant synthesis and alveolarization.Clinical studies revealed that there is a higher proportion of assisted ventilation, respiratory distress syndrome(RDS)and bronchopulmonary dysplasia(BPD), and longer aerobic duration in neonates with Vitamin D deficiency.Therefore, this article systematically reviewed the effects of Vitamin D on lung development, surfactant synthesis, RDS, and BPD.

Advances in pharmacological action and quality control of Yaotongning Capsule / 中草药

Yaotongning Capsule is composed of Strychni Semen Pulveratum, Eupolyphaga Steleophaga, Cyathulae Radix, Glycyrrhizae Radix et Rhizoma, Ephedrae Herba, Olibanum, Myrrha, Scorpio, Bombyx Batryticatus and Atractylodis Rhizoma, which is widely used for the treatment of lumbar and leg pain, e.g. lumbar disc herniation, in clinic. Through literature analysis, the research progress of pharmacology and quality control of Yaotongning Capsule was summarized in order to provide references for the clinical use and quality research of Yaotongning Capsule.

Design, synthesis, and biological evaluation of novel polymyxin B analogues / 药学学报

Polymyxin B and polymyxin E (colistin) are increasingly used as last-resort drugs for treatment of infections caused by multidrug-resistant gram-negative pathogens. Unfortunately, the application was limited due to the serious side effects, especially nephrotoxicity. Very recently, the need for developing more tolerated and more effective polymyxin analogues has grown. This study details the design, synthesis, and evaluation of two classes of polymyxin B analogues with varying hydrophobicity and bulkiness at the N-terminal fatty acyl chain or position 6 amino acid. 20 polymyxin B analogues were synthesized and the chemical structures of the analogues were confirmed by HR-MS and 1H NMR spectra. Compounds 7e (MIC: 0.5-4 μg·mL-1) and 7l (MIC: 0.25-2 μg·mL-1) showed similar or better antimicrobial activity against both susceptible and resistant strains of Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa compared to polymyxin B (MIC: 0.5-2 μg·mL-1). Besides, compound 7l (CC50: 217.1±13.2 μg·mL-1) displayed noticeably decreased renal cytotoxicity compared to polymyxin B (CC50: 120.3±6.0 μg·mL-1). This work establishes the base of further study on the structure-activity relationship of polymyxin B.

Anti-MRSA activities of cycloberberine derivatives with a novel chemical scaffold / 药学学报

Using CBBR as the parent core constructed in our lab, we designed and synthesized 15 novel compounds with diverse structures for evaluation of anti-bacterial activities. Structure activity relationship studies revealed that ① ring C was essential for the activity; ② 7,8- or 8,13-disubstituted CBBR derivatives showed ideal activities, weaker or similar to those corresponding to 7-, 8-, or 13-monosubstituted CBBR derivatives. Among those, compound 9a showed the most potential activity against MRSA/VISA isolates with MIC values of 1-2 μg·mL-1, much better than Lev. 9a also displayed higher stability in the plasma and liver microsomes. Molecular docking indicated that 9a might target bacterial DNA Topo IV ParE subunit, indicating a mode of action distinct from current antibacterial drugs on market. The results provided key scientific evidence for developing such compounds into a new family of anti-MRSA drugs.

Research progresses of small molecule inhibitors targeting TGF-β and its receptors / 药学学报

Transforming growth factor-β (TGF-β) belongs to a group of biologically active cytokines that bind to its receptors to activate Smad signaling and non-Smad signaling pathways. The biological functions of TGF-β include promoting cell epithelial-mesenchymal transition, tissue fibrosis, angiogenesis and tumor immune evasion, as well as dual effects of cancer suppression and cancer promotion. Given the fact that the ligand- and receptors-mediated abnormal activation of TGF-β signaling pathways play an important role in the pathogenesis of multiple diseases such as malignant tumors and tissue fibrosis, more than a dozen small-molecule inhibitors have been developed to block the TGF-β signaling pathways, providing a novel method for controlling the development of these diseases. At present, pirfenidone, an inhibitor for TGF-β production, has been approved for treatment of idiopathic pulmonary fibrosis, while the inhibitors of TGFβRI/ALK5 for therapeutics of tumors or myelodysplastic syndromes, including LY2157299, EW-7197 and LY3200882, are in the phase I to III clinical trials, with additional ones inhibiting TGFβRs such as SB-431542, LY2109761, TP-0427736, and IN-1130 being in the preclinical phase. This paper reviews recent advances in research of small-molecule inhibitors targeting TGF-β and its receptors.

Correlation of Serum Albumin with Renal Function in Patients with Acute Leukemia / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between serum albumin and renal function in patients with acute leukemia (AL) and its clinical significance.</p><p><b>METHODS</b>The clinical data and related test results of 267 newly diagnosed patients with acute leukemia from April 2015 to April 2017 were collected for retrospective cross-sectional analysis. Multivariate regression model was used for statistical analysis.</p><p><b>RESULTS</b>The creatinine level in serum of newly diagnosed acute leukemia patients decreased with the increase of albumin level (the first quartile-the fourth quartile had an average creatinine level of 72.0 µmol/L, 65.2 µmol/L, 62.8 µmol/L, 58.6 µmol/L); Multiple regression model results showed that each elevated albumin 1 g/L, the serum creatinine level decreased 0.89 µmol/L. The serum albumin was grouped into the model by quartile, and the first quartile was used as the reference group. With the increase of albunin, the β value decreased steply (the second and fourth quartile β values were -12.7, -14.81, -15.98), the trend line test p value was <0.05.</p><p><b>CONCLUSION</b>Serum albumin negatively correlats with creatinine level in newly diagnosed acute leukemia patients, and its elevation shows protective effect on renal function.</p>

Effects of allogeneic mouse adipose-derived mesenchymal stem cell-microporous sheep acellular dermal matrix on healing of wound with full-thickness skin defect in mouse and the related mechanism / 中华烧伤杂志

Objective@#To explore the allogeneic mouse adipose-derived mesenchymal stem cell (ADSC)-microporous sheep acellular dermal matrix (ADM) on healing of wound with full-thickness skin defect in mouse and the related mechanism.@*Methods@#One Kunming mouse was sacrificed by cervical dislocation to collect adipose tissue from inguinal region. Mouse ADSCs were isolated from the adipose tissue and cultured in vitro. Cells of the third passage were identified by cell adipogenic and osteogenic differentiation. The expressions of CD73, CD90, CD105, and CD34 were analyzed by flow cytometry. After one sheep was sacrificed, microporous sheep ADM was prepared from sheep back using decellularization method and freezing-thawing method. A 12 mm diameter, round, full-thickness skin defect wound was made on the back of each one of 36 Kunming mice. The wounds were covered by microporous sheep ADM. The mice were divided into group ADSC and control (C) group with 18 mice in each group according to the random number table after surgery. A volume of 0.2 mL DMEM/F12 culture medium containing 1×106 ADSCs was injected between microporous sheep ADM and wound of mice in group ADSC. While 0.2 mL DMEM/F12 culture medium was injected between microporous sheep ADM and wound of mice in group C. On post surgery day (PSD) 12 and 17, wound healing rates of mice in the 2 groups were calculated. On PSD 7, 12, and 17, wound vascularization of mice in the 2 groups was observed under reverse irradiation of backlight. On PSD 7, 12, and 17, the wound granulation tissue of mice in group ADSC was observed by hematoxylin and eosin staining. On PSD 7, the thicknesses of granulation tissue of mice in the 2 groups was measured. On PSD 12 and 17, expressions of VEGF in wounds of mice in the 2 groups were detected by immunohistochemical method. The sample number was 6 in each group at each time point in the above experiments. Data were processed with t test and analysis of variance of factorial design.@*Results@#(1) After 7 days of adipogenic induction, lipid droplet was observed in cytoplasm using oil red O staining. After 21 days of osteogenic induction, black deposits of calcium salts were detected using silver nitrate staining. Expression rates of CD73, CD90, CD105, and CD34 in cells were 97.82%, 99.32%, 97.35%, and 5.88% respectively. The cells were identified as ADSCs. (2) The wound healing rates of mice in group ADSC on PSD 12 and 17 [(78±6)%, (98±3)%] were significantly higher than those in group C [(60±9)%, (90±4)%, t=4.26, 4.46, P<0.01]. (3) On PSD 7, no vessel obviously grew into the center of wounds of mice in the 2 groups, while the granulation tissue has covered the wounds of mice in group ADSC. On PSD 12, the vessels were more abundant in wounds of mice in group ADSC than those in group C. On PSD 17, big vessels crossing the whole wounds was observed in wounds of mice in group ADSC, while big vessels were observed without crossing the whole wounds in wounds of mice in group C. (4) The wounds were covered with thin granulation tissue on PSD 7, and the granulation tissue began to thicken on PSD 12 and were covered by epidermis on PSD 17 in wounds of mice in group ADSC. On PSD 7, the granulation tissue in wounds of mice in group ADSC [(0.62±0.05) mm] was significantly thicker than that in group C [ (0.31±0.04) mm, t=12.27, P<0.01]. (5) On PSD 12 and 17, expressions of VEGF in wounds of mice in group ADSC [(80.7±2.2), (0.98±0.03)/mm2] were significantly than those in group C [(59.5±2.4), (81.5±2.6)/mm2, t=15.95, 14.14, P<0.01].@*Conclusions@#Allogeneic mouse ADSC-microporous sheep ADM can accelerate angiogenesis and growth of granulation tissue, thus promoting wound healing, which may be due to the increase of expression of VEGF.

Non-targeted metabolomics in septic mice infected with Klebsiella pneumoniae / 药学学报

UHPLC-QTOF-MS was applied to non-targeted metabolomics study of mice infected with K. pneumoniae ATCC® BAA 2146 to discover potential biomarkers and metabolic pathways that are associated with sepsis. Fifty-eight metabolites were identified by principal components analysis (PCA) and partial least-squares discriminant analysis (OPLS-DA), which was combined with variable projection importance (VIP) and nonparametric test. Eighteen of the 58 metabolites were further found to be involved in 8 metabolic pathways, including nicotinate and nicotinamide metabolism, pyrimidine metabolism, vitamin B6 metabolism, taurine and hypotaurine metabolism, arginine and proline metabolism, alanine, aspartate and glutamate metabolism, D-glutamine and D-glutamate metabolism and glycerophospholipid metabolism.

Design, synthesis and anti-MRSA activities of cycloberberine derivatives with a novel chemical scaffold / 药学学报

9-Acetoxycycloberberine (1) with a unique skeleton was first identified to display a potent antimicrobial profile against methicillin-resistant Staphylococcus aureus (MRSA) with MIC values of 1-16 μg·mL-1. Taking the compound as a lead, 14 target cycloberberine analogues with diverse structures, such as berberine and chelerythrine derivatives, were synthesized and evaluated for their anti-bacterial activities. Analysis of the structure-activity relationship revealed that:① ring E was essential for the activity; ② the removing of ring B decreased the activity against MRSA. However, the antimicrobial activity against vancomycin-resistant Enterococcus faecium (VRE) was improved; ③ the introduction of a suitable rigid substituent at the 9-position was beneficial for the activity. Among them, compound 9a showed the most potential activity against methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA isolates with MIC values of 0.5-1 μg·mL-1, suggesting a different mechanism from clinical drugs. It displayed higher stability in blood. Therefore, we consider 9a worthy of further investigation. The results provide key scientific evidence for development of such compounds into a new type of anti-MRSA candidates.

Statins Regulate the Proliferation and Apoptosis of T-ALL Cells through the Inhibition of Akt Pathway / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of Statins on proliferation and apoptosis in human acute T lymphocytic leukemia (T-ALL) cells and its possible mechanism.</p><p><b>METHODS</b>Jurkat and CCRF-CEM cells were cultured in different concentrations of Fluvastatin and Simvastatin for 24 h respectively. Then, the cell growth inhibition level was defected by CCK-8; the DNA replication was analyzed by EdU; the cell apoptosis was analyzed by Annexin V/7-AAD double labeling; the cell cycle changes were analyzed by flow cytometry; the expressions of Cyclin D1, p21, p27, BAX, BCL-2 and p-Akt were determined by Western blot.</p><p><b>RESULTS</b>Fluvastatin and Simvastatin both significantly inhibited the growth of Jurkat and CCRF-CEM cells in a dose-dependent manner. The inhibitory rate of Jurkat and CCRF-CEM cells at 0.2 mmol/L Fluvastatin was 41.14% and 57.08% respectively, while the 0.2 mmol/L Simvastatin could supress 68.42% of Jurkat and 77.10% of CCRF-CEM cells. Half or more than half of cell inhibition were observed in Statins-treated groups with significantly statistical differences, compared with the control groups (P<0.05). After the Jurkat and CCRF-CEM cells were treated with Fluvastation and Simvastation of different concentrations for 24 hours, the proportion of early and later apoptotic cells both increased; moreover, the total apoptotic rate increased significantly(P<0.05) at 0.2 mmol/L and 0.3 mmol/L concentration of Fluvastatin and Simvastatin. The detection of cell cycle showed that both of Jurkat and CCRF-CEM cells were arrested in G phase. Western blot revealed that, in comparison with the control group, the expressions of BAX, p21 and p27 in cells treated with Statins were up-regulated, while Cyclin D1, BCL-2 and p-Akt expressions were down-regulated.</p><p><b>CONCLUSION</b>Statins can suppress T-ALL cell proliferation and induce cell apoptosis through the inhibition of Akt pathway.</p>

In vitro metabolism and drug-drug interaction potential of IG-105, a novel antimicrotubule agent / 药学学报

IG-105, N-(2,6-dimethoxypyridine-3-yl)-9-methylcarbazole-3-sulfonamide, a novel antimicrotubule agent, showed potent anticancer activity in a variety of human tumor cells in vitro and in vivo. In order to characterize the metabolism and the possible drug-drug interaction of IG-105, we carried out a series of experiments. Drug metabolizing enzymes involved in IG-105 metabolism were investigated by using pooled human liver microsomes (HLMs) and recombinant cytochrome P450 isoforms (rP450s) respectively. The possible metabolites were analyzed by liquid chromatography-orbitrap-mass spectrometry (LC-Orbitrap-MS). The inhibitory effect of IG-105 on main P450 enzymes was also evaluated. The results showed that IG-105 can be metabolized by a series of rP450s, including CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4 and CYP3A5, with the major contribution enzymes being CYP1A2, CYP2B6, CYP2C19, and CYP3A. Three metabolites (M1-M3) were identified and demethylation was the major phase I metabolic reaction for IG-105. IG-105 moderately inhibited CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A enzyme activities with IC50 values of 6.42, 23.64, 0.39, 1.4, and 3.14 μmol·L-1, respectively. Since the biotransformation of IG-105 involves multiple enzymatic pathways, the compound is less likely to be a victim of a concomitantly used medicine which inhibits activity of one of the CYPs. However, as IG-105 showed medium to strong inhibition on CYP1A2, CYP2D6, CYP3A, and CYP2C19, caution is particularly needed when IG-105 is co-administrated with other anticancer drugs which are mainly metabolized by the above enzymes.

Anti-oxidative activities of supernatants of human fetal placental mesenchymal stem cells cultured in serum-free medium / 中国组织工程研究

BACKGROUND:Current research on mesenchymal stem cels (MSCs) is mostly focused on its immune regulatory function, while little is reported on the antioxidant capacity of the cels and culture supernatant.OBJECTIVE: To investigate the anti-oxidative capacity of the supernatant harvested from human fetal placenta MSCs (fPMSCs) under a condition of serum free culture. METHODS:fPMSCs were cultured with serum free media, and the supernatants of cels at passages 2-6 were colected at 48 hours after culture. Vitamin C was added into the culture medium, as a positive control, and its concentration was 100 μmol/L. The total antioxidant capacity, scavenging capacity of free radicals and antioxidant enzymatic activities of supernatants were measured. RESULTS AND CONCLUSION: By comparing anti-oxidative activities of vitamin C and na?ve culture medium, supernatants colected from fPMSCs cultures exhibited obvious antioxidant capacities at different extents between passages of cel cultures. The total antioxidant capacity of the culture supernatant was comparable to 40-80 μmol/L vitamin C. In addition, al supernatants derived from cels with different passages displayed capacities to scavenge free radicals, including 2,2-diphenyl-1-picrylhydrazyl radical (DPPH?), hydroxyl radical (?OH), superoxide anion radical (O2-). Even more, activities of antioxidant enzymes, including superoxide dismutase and glutathione peroxidase, were also detected in supernatants colected from different passages of fPMSCs. Under the serum-free condition, the culture supernatants of fPMSCs have antioxidant capacities at certain extent. However, the antioxidant components and underlying mechanisms need to be further studied.

Protective role of serum-free supernatant of human placental fetal mesenchymal stem cells against oxidative stress injury to lung epithelial cells / 中国组织工程研究

BACKGROUND: Preliminary experimental studies have shown that the supernatant of human placental fetal mesenchymal stem cells (fPMSCs) has a certain ability to scavenge reactive oxygen species and itself has a certain antioxidant enzyme activity. OBJECTIVE: To investigate the protective role and mechanism of fPMSCs supernatant in serum-free culture on oxidative stress-injured lung epithelial cells. METHODS: Different concentrations of hydrogen peroxide produced oxygen stimulation to lung epithelial cell lines A549 for 6, 12, 24 hours, and the survival rate of lung epithelial cells was detected using cell counting kit-8 method. When the survival rate of lung epithelial cells was 50%, the concentration of hydrogen peroxide was most suitable to make an oxidative damage model. The validity of the model was verified using Hocheest33258 staining and western blot. fPMSCs were cultured in serum-free culture medium, and the supernatant of passage 3 cells was collected. Afterwards, the injured lung epithelial cells were cultured in the fPMSCs cell supernatant for 24 hours. Meanwhile, injury group (oxidative damage only) and vitamin C group (100 μmol/L vitamin C was added in the medium) were established. In the three groups, cell apoptosis was detected by flow cytometry; and western blot was used to detect apoptosis-related proteins and proteins related to the Nrf2-Keap1-ARE signaling pathway. RESULTS AND CONCLUSION: After oxygen stimulation by 600 μmol/L hydrogen peroxide for 24 hours, the survival rate of A549 cells was (56.41±3.31)% as ascertained by the cell counting kit-8 assay. Findings from Hocheest33258 staining and western blot further confirmed the reliability of this model. Flow cytometry results showed that the apoptosis rate in the vitamin C group and the supernatant group decreased to some extent compared with the injury group, and the difference between the supernatant group and the injury group was statistically significant (P < 0.05). In addition, the expression of Bax significantly decreased and the expression of Bcl-2 significantly increased in the vitamin C group and the supernatant group as detected by western blot assay, in comparison with the injury group (P < 0.05). Compared with the injury group, the expression of Nrf2 protein increased and the expression of Keap1 decreased in the vitamin C group and the supernatant group (P < 0.05). These findings suggest that fPMSCs supernatant has a certain antioxidant capacity, and may attenuat oxidative damage and inhibit apoptosis in A549 cells. The mechanism is probably related to the Nrf2-Keap1-ARE signaling pathway.

Identification of 3-demethylchuangxinmycin from Actinoplanes tsinanensis CPCC 200056 / 药学学报

Chuangxinmycin (CM) from Actinoplanes tsinanensis was an antibiotic discovered by Chinese scientists about 40 years ago. It contains a new heterocyclic system of indole fused with dihydrothiopyran, whose biosynthetic mechanism remains unclear. CM is used as an oral medicine in the treatment of bacterial infections in China. The simple structure makes CM as an attractive candidate of structure modification for improvement of antibacterial activity. Recently, we analyzed the secondary metabolites of Actinoplanes tsinanensis CPCC 200056, a CM producing strain, as a natural CM analogue. We discovered the first natural CM analogue 3-demethylchuangxinmycin (DCM) as a new natural product. Compared to CM, DCM exhibited a much weaker activity in the inhibition of the bacterial strains tested. The finding provides valuable information for the structure-activity relationship in the biosynthesis of CM.