Latest ArticlesThe interaction between Mycobacterium tuberculosis and host, as well as the regulation of some signaling pathways in the host, were involved in pathogen latency in macrophages. microRNAs (miRNAs) regulate the gene expression and biological functions, indicating that miRNAs played a regulatory role in bacterial infections. However, whether the host's miRNAs were also involved in the process of Mycobacterium tuberculosis infection had not been thoroughly studied. This study infected macrophages with pathogenic Mycobacterium tuberculosis strain H37Rv and low virulence strain H37Ra to explore the functional miRNAs. By identifying the expression profile of miRNAs in host cells after infection, the expression of 17 miRNAs significantly changed (P<0.05) in the human macrophage THP-1 infected with highly pathogenic H37Rv strain (Rv), H37Rv inactivated strain (Rv-), and non-pathogenic H37Ra (Ra) strains respectively, indicating that host miRNAs may be involved in the interaction of Mycobacterium tuberculosis and host. Meanwhile, 10 types of miRNAs showed significant differences in cells infected with pathogenic and non-pathogenic Mycobacterium tuberculosis, suggesting that host miRNAs may play an important role in the pathogenicity and intracellular survival of Mycobacterium tuberculosis. Further study had found that miR-449a, miR-502-5p, and miR-708 were downregulated in cells infected with Mycobacterium marinum. Overexpression of these three miRNAs displayed the significant inhibitory effect on the growth of Mycobacterium marinum, indicating that miRNAs played a pivotal role in the interaction between the host and Mycobacterium marinum. This study provided the new insights into the pathogenesis of Mycobacterium tuberculosis and the treatment of tuberculosis.
UDP glycosyltransferase (UGT) is a terminal modifying enzyme for the formation of flavonoid glycosides. In this study, we obtained two glycosyltransferase genes, CtUGT25 and CtUGT18, which are closely related to the synthesis of safflower flavonoids, through the Pierce correlation analysis of the expression of glycosyltransferase genes in the safflower corolla transcriptome database at different developmental stages with the contents of the major constituents of safflower metabolome database, and bioinformatically analyzed the gene and protein sequences of the two genes. Expression pattern analysis revealed that CtUGT25 was mainly expressed in the corolla, with the highest expression on day 3 of flowering stage; CtUGT18 was mainly expressed in the root, with the highest expression on day 1 of flowering stage. Functional validation was verified in safflower by Agrobacterium-mediated pollen-tube pathway transgenesis method, demonstrating that CtUGT25 promoted the accumulation of kaempferol-3-O-glucoside and hydroxysafflor yellow A (HSYA), and CtUGT18 promoted the accumulation of kaempferol-3-O-glucoside and orientin, both of which may be the glycosyl-modifying enzymes for the synthesis of safflower flavonoids. Meanwhile, in vitro experiments demonstrated the catalytic activity of CtUGT25 protein on naringenin, quercetin, apigenin, kaempferol, luteoin, 2-hydroxynaringenin and galangin. This study serves as reference for future advancements in regulating the quality of safflower using molecular biotechnology, particularly focuses on the industrial production of safflower exclusive component HSYA. Additionally, it offers valuable insights for researching related genes in other plants.
cAMP response element binding protein (CREB) is an eukaryotic intranuclear protein widely expressed in a variety of organs, and its activation increases the transcriptional activity of downstream genes and promotes the expression of related genes. The neuronal function of CREB is related to many intracellular processes, such as proliferation, differentiation, survival, long-term synaptic potentials, neurogenesis and neuronal plasticity. Increasing evidence has demonstrated that CREB plays an important role in the stroke development and therefore, it may serve as a potential target for stroke therapy. Since some herbal medicines as well as their active ingredients regulate the CREB signaling, this article will summarize the role of CREB signaling pathway in stroke pathophysiology. The research progress of traditional Chinese medicine and its active ingredients modulating CREB activity will also be discussed, with the aim of providing the basis and reference for the future research and development of natural medicines against stroke.
Rapid epidemiological screening for tuberculosis (TB) usually uses tuberculin pure protein derivative (PPD) skin test, which has limitations such as low specificity and high side effects. ESAT-6 and CFP-10 are secreted proteins of Mycobacterium tuberculosis, but the related genes are missing from Bacillus Calmette-Guerin (BCG). In this study, the fusion protein ESAT6-CFP10 (EC) was expressed and purified, and prepared into chitosan nanoparticles (EC-NPs), which were loaded into the microneedle patch and carried out the preliminary test of tuberculosis skin test. The drug loading capacity of MNP-EC-NPs (microneedle patch, MNP) can reach 0.03 μg per needle and 1.92 μg per patch. The shelf life of MNP-EC-NPs can reach 6 months at room temperature, and it can effectively penetrate the epidermis. Volunteer skin test results showed that MNP-EC-NPs can effectively distinguish between BCG vaccinators, and can effectively show positive reaction in the skin of tuberculosis patients without significant side effects. The experiment was approved by the Ethics Committee of Wuhan Pulmonary Hospital [2022 (2)]. In this study, a TB skin test method was established, using ESAT6-CFP10 fusion protein instead of PPD, and using soluble microneedle dosage form, which improved the specificity of TB skin test diagnosis and provided a new technical scheme for TB epidemic screening.
Celastrol and wilforlide A are the main active triterpenoids of the traditional Chinese medicine Lei Gong Teng, which have anti-tumour, anti-inflammatory and immunosuppressive activities, and are the material basis for the clinical efficacy of Lei Gong Teng-related Chinese medicinal preparations. By analysing the biosynthetic pathway of active ingredients, optimizing genetic elements and utilizing "cell factory" to produce triterpenoids heterologously will be an effective way to obtain from Tripterygium wilfordii in the future in a "low-cost and high-efficient" manner. CYP712Ks are the first cytochrome P450s involved in the skeleton modification of friedelane-type and oleanane-type triterpenoids in T. wilfordii, and they can catalyse the generation of polpunonic acid from friedelin and 3-epi-katonic acid from β-amyrin by carboxylation at C-29 position. In this study, four multifunctional TwCYP712K1/2/3/5 were used to clarify the catalytic function and substrate selection preference using in vivo functional characterization in Saccharomyces cerevisiae. The spatial structure of the protein-substrate binding was clarified through homology modeling and molecular docking, and then the differential amino acids in the active pocket of the protein were mutated to clarify the crucial amino acids determining the catalytic function and the selection of substrate structure. A total of 63 mutant elements were constructed, and the amino acid sites affecting the carboxylation function of TwCYP712Ks were analyzed. In particular, the key amino acids affecting the substrate selectivity of TwCYP712K2 towards oleanane-type and friedelane-type triterpenoids were revealed and the TwCYP712K2F127I and TwCYP712K2A227T mutants would result in a reversal of the product ratio. In conclusion, four proteins of TwCYP712Ks were semi-rationally designed by homologous protein alignment and mutual mutation to elucidate multiple amino acid sites determining the catalytic function of the proteins, and a series of activity-enhancing or altering mutants were obtained, which provide abundant catalytic elements for the biosynthesis of active triterpenoids from T. wilfordii, and the mechanism of carboxylation in the C-29 position was initially elucidated.
The compounds were isolated and purified by silica gel, MCI, Sephadex LH-20 and semi-preparative high performance liquid chromatography. The structures of the compounds were determined by NMR and MS spectroscopic data. Twenty monomer compounds were isolated from the ethyl acetate extract of Lindera reflexa root from Hunan province, and identified as: (1″S, 3″S, 6″R)-2′, 4′, 6′-trihydroxy-3′-[1″-(3″-hydroxy)-p-menthanyl]-chalcone (1), sumadain D (2), quercetin (3), catechin (4), epicatechin (5), N-cis-feruloyltyramine (6), N-trans-feruloyltyramine (7), N-trans-feruloyl-3-methoxytyramine (8), flavifloramides B (9), northalifoline (10), isolariciresinol (11), syringaresinol (12), pinoresinol (13), medioresinol (14), dehydroconiferyl alcohol (15), 4-methoxyl-denudaquinol (16), miliusanal (17), syringic acid (18), abscisic acid (19), (E)-cinnamyl-(E)-cinnamate (20). Compound 1 is a new compound, and compounds 2‒20 have been isolated from Lindera reflexa for the first time. The results showed that compounds 1, 2, 3 and 16 could significantly reduce the survival ability of MGC-803 cells with IC50 values of 5.58, 23.41, 25.72 and 20.96 μmol·L-1, respectively. Compounds 5 and 20 can reduce the survival ability of MGC-803 cells with IC50 values of 98.83 and 89.26 μmol·L-1, respectively.
A high performance liquid chromatography (HPLC) method utilizing correction factors was established for the quantitative detection of related substances in flumazenil. Separation was achieved using an Agilent Pursuit XRs C18 column (250 mm × 4.6 mm, 5 μm) with an isocratic elution of dilute phosphoric acid, methanol, and tetrahydrofuran as the mobile phases. Correction factors calculated from a standard curve method were applied to determine the impurity content. The quantification of impurities in flumazenil was conducted using both external standard and correction factor methods, followed by validation and comparison of the two. For the identification of degradation products, a forced degradation approach was employed to prepare a flumazenil degradation solution, and the resulting impurities were confirmed by LC-MS analysis. The separation of flumazenil and its impurities was found to be efficient. The limits of quantification for impurities A, B, D, and E were established at 0.169 9, 0.314 7, 0.143 9, and 0.270 8 ng, respectively, with the limits of detection at 0.055 8, 0.096 9, 0.048 8, and 0.089 0 ng. These impurities demonstrated a strong linear relationship across the concentration ranges of 0.034 9-7.847 0, 0.038 7-8.710 7, 0.034 6-7.794 1, and 0.032 4-7.292 8 µg·mL-1, respectively (n = 7). The method achieved average recoveries between 98.25% and 99.42%, with an RSD of less than 2.0% (n = 9), indicating high accuracy. The external standard and correction factor methods were used to determine the related substances in flumazenil, and the results of the two methods were consistent. The established HPLC method is characterized by its high accuracy, sensitivity, and repeatability, and is suitable for determining related substances in flumazenil.
In order to solve the problem of resistance of Pseudomonas aeruginosa to multiple antibiotics, it is an effective way to find inhibitors of P.aeruginosa efflux pump. In this study, 15 new ornithine peptidomimetic derivatives were designed and synthesized by changing the side chain structure of natural amino acids with PAβN, a dipeptide efflux pump inhibitor, and their synergic activity with aztreonam, a monocyclic β-lactam antibiotic, against P.aeruginosa was evaluated. Among them, the representative compound 12b not only enhanced the antibacterial activity of β-lactam antibiotics aztreonam, ceftazidime and meropenem, but also significantly enhanced the antibacterial action of macrolide antibiotics clarithromycin, showing a broad-spectrum synergic sensitization effect. In addition, compound 12b also has a good safety. Preliminary mechanisms suggest that 12b works by directly targeting the efflux transporter MexB. These results provide a new lead compound for the development of a new class of efflux pump inhibitors against P.aeruginosa.
This study aimed to investigate the role and mechanism of sappanone A (SA) in regulating renal ischemia-reperfusion injury (IRI) in rats. The animal experiment has been approved by the Ethics Committee of Suzhou Wujiang District Children's Hospital (approval number: 2022010). First, hematoxylin-eosin (H&E) staining was used to evaluate the effects of SA on IRI, and renal damage was scored. Serum creatinine (SCr), blood urea nitrogen (BUN) and cystatin C (Cystatin C) were analyzed. The effect of sappanone A on the apoptosis of renal tubular epithelial cells induced by IRI was analyzed by TUNEL staining. Protein expression levels of p-JNK/JNK, p-ERK/ERK, Bcl2, Bax and cleaved-caspase 3 in renal tissues were detected by Western blot. Finally, H&E staining, serological analysis, TUNEL staining and Western blot were used to determine whether JNK activator anisomycin could reverse the effect of SA on IRI in rats. The results showed SA significantly reduced the renal tubule injury caused by ischemia-reperfusion, and decreased the level of SCr, BUN and Cys C in serum. TUNEL staining showed that SA significantly reduced the apoptosis of renal tubular epithelial cells induced by IRI. Western blot analysis of kidney tissue showed that SA significantly promoted the expression of apoptosis inhibiting protein Bcl2 and inhibited the expression of apoptosis-promoting proteins Bax and cleaved-caspase 3. Further analysis elucidated that SA did not affect the phosphorylation of ERK but decreased the phosphorylation of JNK. Finally, H&E staining, serological analysis, TUNEL staining and Western blot confirmed that JNK activator anisomycin could reverse the alleviating effect of SA on IRI in rats. The above findings suggest that SA could alleviate IRI in rats by inhibiting JNK phosphorylation.
Acute liver injury (ALI) is one of the common severe diseases in clinic, which is characterized by redox imbalance and inflammatory storm. Untimely treatment can easily lead to liver failure and even death. Rosmarinic acid (RA) has been proved to have anti-inflammatory and antioxidant activity, but it is not clear how to protect ALI through antioxidation and inhibition of inflammation. Therefore, this study explored the therapeutic effect and molecular mechanism of RA on ALI through in vitro and in vivo experiments. In the mouse ALI model, the effects of RA on liver function and inflammatory indexes were studied, the pathological changes of liver were observed by HE, the effect of RA on reactive oxygen species in liver was detected by fluorescence method, and the level of F4/80 in liver tissue was detected by immunohistochemical method. The levels of thioredoxin interacting protein (TXNIP), NOD-like receptor protein 3 (NLRP3) and cysteinyl aspartate specific proteinase-1 (CASPASE-1) in liver tissue were measured by Western blot. All animal welfare and experimental procedures follow the rules of the Animal Ethics Committee of Southwest Minzu University. In vitro, human hepatoma cell line HepG2 was used to establish the model of oxidative damage induced by H2O2. The cell viability was detected by CCK-8 method. The level of interleukin-1β (IL-1β) in the supernatant was detected by enzyme linked immunosorbent assay (ELISA), the activity of lactatede hydrogenase (LDH) was detected by LDH kit, and the level of ROS was detected by fluorescence probe DCFH-DA labeling. The mRNA expression of Txnip, Nlrp3, Caspase 1, Il1β was detected by real-time fluorescence quantitative PCR (qPCR), and the protein levels of nuclear factor erythroid-2 related factor 2 (NRF2), TXNIP, NLRP3 and CASPASE-1 were measured by Western blot. The results showed that compared with the model group, the degree of liver swelling, tissue injury, liver function index in RA group were significantly lower than those in model group. And RA significantly attenuated the increases of ROS in liver tissue. The expression levels of TXNIP, NLRP3 and CASPASE-1 in liver tissue were significantly lower than those in model group. Additionally, RA inhibited the expressions of F4/80 and IL-1β. In vitro experiment, compared with model group, RA effectively inhibited the secretion of IL-1β and LDH. The level of ROS also decreased significantly. RA inhibited the mRNA expressions of Txnip, Caspase 1, Il1β. Furthermore, RA significantly increased the expression level of NRF2 protein in nucleus, and decreased the expression level of TXNIP and NLRP3 protein. Specifically, with the addition of ML385, the effect of RA on NRF2, TXNIP, NLRP3, CASPASE-1 protein expression was reversed. Collectively, these findings suggested that RA may inhibit the production of ROS by promoting NRF2 nuclear transfer, and then reduce the activation of NLRP3 inflammatory bodies by TXNIP, reduce cell death and inflammatory response to prevent the liver injury.