The use of melittin to enhance transgene expression mediated by recombinant adeno-associated virus serotype 2 vectors both in vitro and in vivo / 中西医结合学报

OBJECTIVE@#Melittin, a cell-penetrating peptide, improves the efficiency of many non-viral gene delivery vectors, yet its application in viral vectors has not been well studied. The non-pathogenic recombinant adeno-associated virus (rAAV) vector is an ideal in vivo gene delivery vector. However, its full potential will only be achieved after improvement of its transduction efficiency. To improve the transduction efficiency of rAAV2 vectors, we attempted to develop a melittin-based rAAV2 vector delivery strategy.@*METHODS@#The melittin peptide was inserted into the rAAV2 capsid either in the loop VIII of all viral proteins (VPs) or at the N terminus of VP2. Various rAAV2-gfp or -fluc vectors were subjected to quantitative real-time polymerase chain reaction and Western blot assays to determine their titers and integrity of capsid proteins, respectively. Alternatively, the vectors based on wild-type capsid were pre-incubated with melittin, followed by transduction of cultured cells or tail vein administration of the mixture to C57BL/6 and BALB/c nude mice. In vivo bioluminescence imaging was performed to evaluate the transgene expression.@*RESULTS@#rAAV2 vectors with melittin peptide inserted in the loop VIII of VPs had low transduction efficiency, probably due to dramatically reduced ability to bind to the target cells. Fusing the melittin peptide at the N-terminus of VP2 produced vectors without the VP2 subunit. Interestingly, among the commonly used rAAV vectors, pre-incubation of rAAV2 and rAAV6 vectors with melittin significantly enhanced their transduction efficiency in HEK293 and Huh7 cells in vitro. Melittin also had the ability to increase the rAAV2-mediated transgene expression in mouse liver in vivo. Mechanistically, melittin did not change the vector-receptor interaction. Moreover, cell counting kit-8 assays of cultured cells and serum transaminase levels indicated melittin had little cytotoxicity.@*CONCLUSION@#Pre-incubation with melittin, but not insertion of melittin into the rAAV2 capsid, significantly enhanced rAAV2-mediated transgene expression. Although further in vivo evaluations are required, this research not only expands the pharmacological potential of melittin, but also provides a new strategy to improve gene therapy mediated by rAAV vectors.

Study on construction of c-Met specific CAR-T cells and its killing effect on non-small cell lung carcinoma / 中华肿瘤杂志

Objective: To produce chimeric antigen receptor T cells (CAR-T) targeting human hepatocyte growth factor/c-Met (HGF/c-Met) protein and detect its cytotoxicity against non-small cell lung cancer (NSCLC) cells H1975 in vitro. Methods: The whole gene sequence of c-Met CAR containing c-Met single-chain fragment variable was synthesized and linked to lentiviral vector plasmid, plasmid electrophoresis was used to detect the correctness of target gene. HEK293 cells were transfected with plasmid and the concentrated solution of the virus particles was collected. c-Met CAR lentivirus was transfected into T cells to obtain second-generation c-Met CAR-T and the expression of CAR sequences was verified by reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) and western blot, and the positive rate and cell subtypes of c-Met CAR-T cells were detected by flow cytometry. The positive expression of c-Met protein in NSCLC cell line H1975 was verified by flow cytometry, and the negative expression of c-Met protein in ovarian cancer cell line A2780 was selected as the control. The cytotoxicity of c-Met CAR-T to H1975 was detected by lactate dehydrogenase (LDH) cytotoxicity assay at 1∶1, 5∶1, 10∶1 and 20∶1 of effector: target cell ratio (E∶T). Enzyme-linked immunosorbent assay (ELISA) was used to detect the release of cytokines such as TNF-α, IL-2 and IFN-γ from c-Met CAR-T co-cultured with H1975. Results: The size of band was consistent with that of designed c-Met CAR, suggesting that the c-Met CAR plasmid was successfully constructed. The results of gene sequencing were consistent with the original design sequence and lentivirus was successfully constructed. CAR molecules expression in T cells infected with lentivirus was detected by western blot and RT-qPCR, which showed c-Met CAR-T were successfully constructed. Flow cytometry results showed that the infection efficiency of c-Met CAR in T cells was over 38.4%, and the proportion of CD8(+) T cells was increased after lentivirus infection. The NSCLC cell line H1975 highly expressed c-Met while ovarian cancer cell line A2780 negatively expressed c-Met. LDH cytotoxicity assay indicated that the killing efficiency was positively correlated with the E∶T, and higher than that of control group, and the killing rate reached 51.12% when the E∶T was 20∶1. ELISA results showed that c-Met CAR-T cells released more IL-2, TNF-α and IFN-γ in target cell stimulation, but there was no statistical difference between c-Met CAR-T and T cells in the non-target group. Conclusions: Human NSCLC cell H1975 expresses high level of c-Met which can be used as a target for immunotherapy. CAR-T cells targeting c-Met have been successfully produced and have high killing effect on c-Met positive NSCLC cells in vitro.

Correction of the pathogenic mutation in the G6PC3 gene by adenine base editing in mutant embryos / 中华血液学杂志

Objective: To determine whether the adenine base editor (ABE7.10) can be used to fix harmful mutations in the human G6PC3 gene. Methods: To investigate the safety of base-edited embryos, off-target analysis by deep sequencing was used to examine the feasibility and editing efficiency of various sgRNA expression vectors. The human HEK293T mutation models and human embryos were also used to test the feasibility and editing efficiency of correction. Results: ①The G6PC3(C295T) mutant cell model was successfully created. ②In the G6PC3(C295T) mutant cell model, three distinct Re-sgRNAs were created and corrected, with base correction efficiency ranging from 8.79% to 19.56% . ③ ABE7.10 could successfully fix mutant bases in the human pathogenic embryo test; however, base editing events had also happened in other locations. ④ With the exception of one noncoding site, which had a high safety rate, deep sequencing analysis revealed that the detection of 32 probable off-target sites was <0.5% . Conclusion: This study proposes a new base correction strategy based on human pathogenic embryos; however, it also produces a certain nontarget site editing, which needs to be further analyzed on the PAM site or editor window.

The Effect of SP1 on the Progression of T-cell Acute Lymphoblastic Leukemia / 中国实验血液学杂志

OBJECTIVE@#To study the transcriptional regulation of SP1 on the scaffold protein ARRB1 and its influence on the progression of T-cell acute lymphoblastic leukemia (T-ALL).@*METHODS@#pGL3-ARRB1-luc, pCDNA3.1-SP1 and other transcription factor plasmids that might be combined were constructed, and the binding of transcription factors to the promoter of ARRB1 was identified by dual luciferase reporter gene assay. Stable cell lines with over-expressed SP1 (JK-SP1) was constructed by lentiviral transfection, and the expression correlation of SP1 with ARRB1 was demonstrated by RT-PCR and Western blot. Further, the apoptosis, cell cycle and reactive oxygen species (ROS) were detected by flow cytometry. The effect of SP1 on propagation of leukemic cells was observed on NCG leukemic mice.@*RESULTS@#The expression of fluorescein were enhanced by co-transfection with pCDNA3.1-SP1 and pGL3-ARRB1-luc plasmids in HEK293T cell line (P<0.001), meanwhile, compared with the control group, the expression of ARRB1 mRNA and protein were increased in JK-SP1 cells (both P<0.01). Further in vitro experiments showed that, compared with the control group, the apoptosis rate was higher (x=22.78%) , the cell cycle was mostly blocked in G1 phase (63.00%), and the content of reactive oxygen species increased in JK-SP1 cells. And in vivo experiments showed that the mice injected with JK-SP1 cells through tail vein had a favorable overall survival time (average 33.8 days), less infiltration in liver and spleen tissue.@*CONCLUSION@#Transcription factor SP1 promotes the transcription and expression of ARRB1 by binding the the promoter of ARRB1 directly, thus delays the progress of T-ALL in vitro and in vivo. The study improves the pathogenesis of ARRB1 regulating the initiation and development of T-ALL, and provides theoretical basis for the development of new possible targeted drugs.

Preparation of mouse monoclonal antibodies against human adenovirus 55 Hexon (HAdV55 Hexon) protein / 细胞与分子免疫学杂志

Objective To prepare specific mouse monoclonal antibody (mAb) against human adenovirus type 55 Hexon protein (HAdV55 Hexon). Methods The Hexon genes of HAdV55, 3, 4, 7, 16 and 21 were chemically synthesized as templates for PCR amplification. The prokaryotic expression plasmids pET28a-HAdV55 Hexon and eukaryotic expression plasmids pCAGGS-HAdV3, 4, 7, 16, 21 and 55 Hexon were constructed respectively. The pET28a-HAdV55 Hexon plasmid was transformed into E. coli competent cell BL21 (DE3) and was induced by IPTG. After the purified inclusion body was denatured and renatured, Hexon55 protein was purified by tangential flow filtration system. pCAGGS-HAdV55 Hexon was used to immunize BALB/c mice by cupping, and HAdV55 Hexon protein was used to booster immunization. The anti-HAdV55 Hexon mAb was prepared by hybridoma technique and the titer and subclass were determined. The specificity of antibody was identified by Western blot using HEK293T cells transfected with pCAGGS-HAdV55 Hexon and by immunofluorescence assay (IFA) using BHK cells transfected with pCAGGS-HAdV55 Hexon. Both clones with high titer were selected, and the cross-reactivity of pCAGGS-HAdV3, 4, 7, 16, 21 and 55 Hexon transfected cells were analyzed by Western blot analysis and IFA. Results PET28a-HAdV55 Hexon and pCAGGS-HAdV55 Hexon, 3, 4, 7, 16 and 21 expression plasmids were successfully constructed. BL21 transformed with pET28a-HAdV55 Hexon was induced by IPTG. The HAdV55 Hexon protein was mainly expressed in the form of inclusion body. After denaturation and renaturation, the purified HAdV55 Hexon protein was obtained by ultrafiltration. Six hybridoma cell lines secreting HAdV55 Hexon mAb were obtained. The antibody subclass analysis showed that 2 strains were IgG2a subtypes and 4 strains were IgG2b. Two specific HAdV55 Hexon antibodies with high titer were obtained, and there was no cross-reactivity with HAdV3, 4, 7, 16, 21 Hexon. Conclusion The specific mice mAb against HAdV55 Hexon provides an experimental basis for establishing its antigen detection method.

Cytotoxicity of 4 Wild Mushrooms in a Case of Yunnan Sudden Unexplained Death / 法医学杂志

OBJECTIVES@#To explore the cytotoxicity of four wild mushrooms involved in a case of Yunnan sudden unexplained death (YNSUD), to provide the experimental basis for prevention and treatment of YNSUD.@*METHODS@#Four kinds of wild mushrooms that were eaten by family members in this YNSUD incident were collected and identified by expert identification and gene sequencing. Raw extracts from four wild mushrooms were extracted by ultrasonic extraction to intervene HEK293 cells, and the mushrooms with obvious cytotoxicity were screened by Cell Counting Kit-8 (CCK-8). The selected wild mushrooms were prepared into three kinds of extracts, which were raw, boiled, and boiled followed by enzymolysis. HEK293 cells were intervened with these three extracts at different concentrations. The cytotoxicity was detected by CCK-8 combined with lactate dehydrogenase (LDH) Assay Kit, and the morphological changes of HEK293 cells were observed under an inverted phase contrast microscope.@*RESULTS@#Species identification indicated that the four wild mushrooms were Butyriboletus roseoflavus, Boletus edulis, Russula virescens and Amanita manginiana. Cytotoxicity was found only in Amanita manginiana. The raw extracts showed cytotoxicity at the mass concentration of 0.1 mg/mL, while the boiled extracts and the boiled followed by enzymolysis extracts showed obvious cytotoxicity at the mass concentration of 0.4 mg/mL and 0.7 mg/mL, respectively. In addition to the obvious decrease in the number of HEK293 cells, the number of synapses increased and the refraction of HEK293 cells was poor after the intervention of Amanita manginiana extracts.@*CONCLUSIONS@#The extracts of Amanita manginiana involved in this YNSUD case has obvious cytotoxicity, and some of its toxicity can be reduced by boiled and enzymolysis, but cannot be completely detoxicated. Therefore, the consumption of Amanita manginiana is potentially dangerous, and it may be one of the causes of the YNSUD.

The two-stage interaction of Ebola virus VP40 with nucleoprotein results in a switch from viral RNA synthesis to virion assembly/budding

Ebola virus (EBOV) is an enveloped negative-sense RNA virus and a member of the filovirus family. Nucleoprotein (NP) expression alone leads to the formation of inclusion bodies (IBs), which are critical for viral RNA synthesis. The matrix protein, VP40, not only plays a critical role in virus assembly/budding, but also can regulate transcription and replication of the viral genome. However, the molecular mechanism by which VP40 regulates viral RNA synthesis and virion assembly/budding is unknown. Here, we show that within IBs the N-terminus of NP recruits VP40 and is required for VLP-containing NP release. Furthermore, we find four point mutations (L692A, P697A, P698A and W699A) within the C-terminal hydrophobic core of NP result in a stronger VP40-NP interaction within IBs, sequestering VP40 within IBs, reducing VP40-VLP egress, abolishing the incorporation of NC-like structures into VP40-VLP, and inhibiting viral RNA synthesis, suggesting that the interaction of N-terminus of NP with VP40 induces a conformational change in the C-terminus of NP. Consequently, the C-terminal hydrophobic core of NP is exposed and binds VP40, thereby inhibiting RNA synthesis and initiating virion assembly/budding.

NEK2 promotes the progression of liver cancer by resisting the cellular senescence / 中南大学学报(医学版)

OBJECTIVES@#Liver cancer is the sixth most common malignant tumor in the world. Hepatocellular carcinoma (HCC) accounts for 85%-90% of all patients with liver cancer. It possesses the characteristics of insidious onset, rapid progression, early recurrence, easy drug resistance, and poor prognosis. NIMA related kinase 2 (NEK2) is a cell cycle regulating kinases, which regulates cell cycle in mitosis. Cellular senescence is a complex heterogeneous process, and is a stable form of cell cycle arrest that limits the proliferative potential of cells. This study aims to investigate the relationship between the expression level of NEK2 and the senescence in hepatoma cells, and to explore the effect of NEK2 expression on hepatoma cell senescence and the underlying molecular mechanism.@*METHODS@#A total of 581 senescence-relevant genes were obtained from the GenAge website. The gene expression data of tumor tissues of 370 HCC patients were downloaded from the Cancer Genome Atlas database. The co-expression of NEK2 and aging-related genes was analyzed by R-package. KEGG was used to analyze the significant gene enrichment pathway of differentially expressed genes in NEK2 overexpression HEK293. The stable transfected cell lines with overexpression and knockdown of NEK2 were constructed in hepatoma cell line SMMC-7721 and HepG2, and senescence-associated β-galactosidase (SA-β-gal) staining was used to detect senescence, the cell proliferation was detected by CCK-8 method and clone formation experiment, the cell cycle was analyzed by flow cytometry, and the expression of proteins related to p53/p21, p16/Rb, and phosphatase and tensin homolog deleted on chromosome ten (PTEN)/Akt signal transduction pathway was detected by Western blotting.@*RESULTS@#There were 320 senescence related genes co-expressed with NEK2. KEGG analysis showed that the senescence signaling pathway was significantly enriched in HEK293 cells with overexpression of NEK2.Compared with SMMC-7721 or HepG2 without knockdown of NEK2, the senescent cells of SMMC-7721 and HepG2 with knockdown of NEK2 were increased, cell proliferation and clone formation were decreased significantly, the percentage of cells in G0/G1 phase was increased, the expression levels of phospho-Akt (p-Akt) and phospho-Rb (p-Rb) protein were decreased significantly, and the expression level of p16 protein was increased significantly (all P<0.05). Compared with SMMC-7721 or HepG2 transfected with blank plasmid, the senescent cells of SMMC-7721 and HepG2 overexpressing NEK2 were decreased, the cell proliferation and clone formation were increased significantly, the percentage of cells in G0/G1 phase were decreased, the expression levels of p-Akt and p-Rb protein were increased significantly, and the expression level of p16 protein was decreased significantly (all P<0.05).@*CONCLUSIONS@#NEK2 may mediate the anti-aging effect of hepatoma cells through p16/Rb and PTEN/Akt signal transduction pathways, which provides a new theoretical basis for NEK2 to promote the progress of liver cancer and a new idea for the targeting treatment for liver cancer.

Protein Kinase C Controls the Excitability of Cortical Pyramidal Neurons by Regulating Kv2.2 Channel Activity / 神经科学通报·英文版

The family of voltage-gated potassium Kv2 channels consists of the Kv2.1 and Kv2.2 subtypes. Kv2.1 is constitutively highly phosphorylated in neurons and its function relies on its phosphorylation state. Whether the function of Kv2.2 is also dependent on its phosphorylation state remains unknown. Here, we investigated whether Kv2.2 channels can be phosphorylated by protein kinase C (PKC) and examined the effects of PKC-induced phosphorylation on their activity and function. Activation of PKC inhibited Kv2.2 currents and altered their steady-state activation in HEK293 cells. Point mutations and specific antibodies against phosphorylated S481 or S488 demonstrated the importance of these residues for the PKC-dependent modulation of Kv2.2. In layer II pyramidal neurons in cortical slices, activation of PKC similarly regulated native Kv2.2 channels and simultaneously reduced the frequency of action potentials. In conclusion, this study provides the first evidence to our knowledge that PKC-induced phosphorylation of the Kv2.2 channel controls the excitability of cortical pyramidal neurons.

Effect of Dimethyl Fumarate (DMF) on T-cell Acute Lymphoblastic Leukemia / 中国实验血液学杂志

OBJECTIVE@#To explore the effect and possible mechanism of dimethyl fumarate (DMF) on T-cell acute lymphoblastic leukemia (T-ALL), and provide experimental and theoretical basis for the clinical treatment of T-ALL.@*METHODS@#Jurkat cells were treated with different concentrations of DMF for 24 hours, and then the proportion and absolute count of Ki67-positive Jurkat cells were analyzed by flow cytometry. Meanwhile, the protein levels of nuclear factor-erythroid 2-related factor 2 (Nrf2) and E3 ubiquitin ligase HACE1 in Jurkat cells treated with DMF for 24 hours were evaluated by Western blot. Nrf2 proteins were co-immunoprecipitated in Jurkat cells, and then HACE1 protein was assessed by Western blot. Plasmids of Flag-Nrf2 and different gradients of Flag-HACE1 were transfected into HEK293T cells, and the levels of Flag-Nrf2 were detected by Western blot after 48 hours.@*RESULTS@#DMF could significantly inhibit the proportion and absolute count of Ki67-positive Jurkat cells, and DMF inhibited the proliferation of Jurkat cells in a dose-dependent manner (r=0.9595, r=0.9054). DMF could significantly up-regulate the protein levels of Nrf2 and E3 ubiquitin ligase HACE1 in Jurkat cells (P<0.01, P<0.01). HACE1 physically interacted with Nrf2 in Jurkat cells. Overexpression of Flag-HACE1 significantly increased the protein level of Flag-Nrf2 in a dose-dependent manner (r=0.9771).@*CONCLUSION@#DMF inhibits the proliferation of T-cell acute lymphoblastic leukemia cell. The mechanism may be that, DMF significantly up-regulates the protein levels of Nrf2 and E3 ubiquitin ligase HACE1, and HACE1 interacts with Nrf2 and positively regulates Nrf2 protein level.

Discovery of exogenous ligands for orphan receptor BRS-3 from Chinese herbs / 中国中药杂志

Bombesin receptor subtype-3(BRS-3) is an orphan receptor in the bombesin receptor family. Its signal transduction mechanism and biological function have attracted much attention. Seeking the ligand for BRS-3 is of great significance for exploring its function. Considering the fact that the activation of BRS-3 receptor can induce the change in intracellular Ca~(2+) concentration, the fluo-rometric imaging plate reader(FLIPR) was utilized for ligand screening at the cellular level. Among more than 400 monomeric compounds isolated from Chinese herbs, yuanhunine from Corydalis Rhizoma and sophoraisoflavanone A and licoriphenone from Glycyrrhizae Radix et Rhizoma antagonized BRS-3 to varying degrees. It was confirmed in HEK293 cells expressing BRS-3 that yuanhunine, sophoraisoflavanone A, and licoriphenone inhibited the calcium current response after the activation of BRS-3 by [D-Phe~6,β-Ala~(11),Phe~(13),Nle~(14)]bombesin-(6-14) in a dose-dependent manner with the IC_(50) values being 8.58, 4.10, and 2.04 μmol·L~(-1), respectively. Further study indicated that yuanhunine and sophoraisoflavanone A exhibited good selectivity for BRS-3. In this study, it was found for the first time that monomers derived from Chinese herbs had antagonistic activity against orphan receptor BRS-3, which has provided a tool for further study of BRS-3 and also the potential lead compounds for new drug discovery. At the same time, it provides reference for the research and development of innovative drugs based on the active ingredients of Chinese herbs.

Construction of recombinant adenovirus expressing capsid protein of serotype O foot-and-mouth disease virus and analysis of its immunogenicity / 生物工程学报

In order to construct a recombinant replication deficient human type 5 adenovirus (Ad5) expressing a foot-and-mouth disease virus (FMDV) capsid protein, specific primers for P12A and 3B3C genes of FMDV-OZK93 were synthesized. The P12A and 3B3C genes were then amplified and connected by fusion PCR, and a recombinant shuttle plasmid pDC316-mCMV-EGFP-P12A3B3C expressing the FMDV-OZK93 capsid protein precursor P12A and 3B3C protease were obtained by inserting the P12A3B3C gene into the pDC316-mCMV-EGFP plasmid. The recombinant adenovirus rAdv-P12A3B3C-OZK93 was subsequently packaged, characterized and amplified using AdMaxTM adenovirus packaging system, and the expression was verified by infecting human embryonic kidney cell HEK-293. The humoral and cellular immunity levels of well-expressed and purified recombinant adenovirus immunized mice were evaluated. The results showed that rAdv-P12A3B3C-OZK93 could be stably passaged and the maximum virus titer reached 1×109.1 TCID50/mL. Western blotting and indirect immunofluorescence showed that rAdv-P12A3B3C-OZK93 expressed the FMDV-specific proteins P12A and VP1 in HEK-293 cells. In addition, the PK cell infection experiment confirmed that rAdv-P12A3B3C-OZK93 could infect porcine cells, which is essential for vaccination in pigs. Comparing with the inactivated vaccine group, the recombinant adenovirus could induce higher FMDV-specific IgG antibodies, γ-IFN and IL-10. This indicates that the recombinant adenovirus has good immunity for animal, which is very important for the subsequent development of foot-and-mouth disease vaccine.

A novel cell tool for α2δ-1-NMDAR target-based analgesic drug discovery / 生物工程学报

The α2δ-1 protein coded by Cacna2d1 is dramatically up-regulated in dorsal root ganglion (DRG) neurons and spinal dorsal horn following sensory nerve injury in various animal models of neuropathic pain. Cacna2d1 overexpression potentiates presynaptic and postsynaptic NMDAR activity of spinal dorsal horn neurons to cause pain hypersensitivity. The α2δ-1-NMDAR interaction promotes surface trafficking and synaptic targeting of NMDARs in neuropathic pain caused by chemotherapeutic agents and peripheral nerve injury, as well as in other pathological conditions such as in the paraventricular nucleus (PVN) with neurogenic hypertension and in the brain with ischemic stroke. The lentiviral transfection method was used to construct a human embryonic kidney HEK293T cell line that could stably express α2δ-1-NMDAR complex. A stably transfected cell line was observed by florescence microscope, and identified by RT-qPCR and Western blotting. The results showed that the HEK293T cell line was successfully transfected and the genes could be stably expressed. Subsequently, the transfected cell line was successfully developed into a target drug screening system using patch clamp techniques. It provides a promising cell model for further research on the interaction mechanism of α2δ-1-NMDAR complex and drug screening for chronic pain and related diseases with low side effects.

Functional characterization of SLC12A1 gene variants in 3 patients with Bartter syndrome type Ⅰ / 中华儿科杂志

Objective: To clarify the molecular basis of patients with Bartter syndrome type I and explore the therapeutic effect of trafficking-defective variations by chemical chaperone 4-Phenylbutyric acid(4-PBA). Methods: The clinical characteristics, laboratory findings and genetic data of 3 patients diagnosed with Bartter syndrome type I who were admitted to Department of Nephrology, Children's Hospital of Nanjing Medical University from 2017 to 2018 were retrospectively analyzed. Wild type and variant SLC12A1 gene constructs were transiently overexpressed in HEK293 cells. Western blotting was used to detect the expression levels of Na+-K+-2Cl-cotransporter(NKCC2) protein. Immunofluorescent staining was applied to investigate the subcellular localization of NKCC2 protein. In addition, the effect of the chemical chaperone 4-PBA on the expression and localization of the SLC12A1 gene variants was investigated. Unpaired t test was used for statistical analysis of 4-PBA treatment. Results: All the 3 patients (2 males and 1 female), aged 3.0, 4.0 and 1.2 years, respectively. All patients had antenatal onset with polyhydramnios and were born prematurely. After birth, all patients presented with hypochlorine alkalosis accompanied by hypokalemia and hyponatremia. Sequencing analysis revealed that the 3 patients were homozygotes or compound heterozygotes for variants in the SLC12A1 gene. In HEK293 cells, the surface expression of NKCC2 in 3 variants (p.L463S, p.L479V, p.507-510del) are all lower than in wild type (0.718±0.039, 0.287±0.081, 0.025±0.156 vs. 1.001±0.028, t=5.92, 8.35, 30.49, all P<0.01). Moreover, the total protein expression of p.L479V and p.507-510del group were all lower than that in wild type group (0.630±0.032, 0.043±0.003 vs. 1.000±0.111, t=3.21, 8.65, all P<0.05). 4-PBA treatment increased the mature protein expression level of the p.L463S and p. L479V group in 4-PBA treatment group are all higher than the untreated group (0.459±0.018 vs. 1.123±0.024, 0.053±0.012 vs. 1.256±0.037, t=2.75, 18.35, all P<0.05). Cytoplasmic retention of the L479V and 507-510del variants were observed by immunofluorescent staining. 4-PBA treatment could rescue a number of NKCC2 L479V variants to the membrane. Conclusions: The 3 SLC12A1 variants cause expression or subcellular localization defects of the protein. The findings that plasma membrane expression and activity can be rescued by 4PBA might help to develop novel therapeutic strategy for Bartter syndrome type Ⅰ.

Eukaryotic expression and antigen epitope prediction of the LRRC15 protein in excretory secretory antigens of Taenia solium cysticercus / 中国血吸虫病防治杂志

OBJECTIVE@#To conduct eukaryotic expression of the leucine-rich repeat containing 15 (LRRC15), a differentially expressed protein in excretory secretory antigens of Taenia solium cysticercus, and predict its antigen epitope.@*METHODS@#The molecular weight, stability, amino acid sequence composition, isoelectric point and T lymphocyte epitope of the LRRC15 protein were predicted using the bioinformatics online softwares ExPASy-PortParam and Protean. The full-length splicing primers were designed using PCR-based accurate synthesis, and the LRRC15 gene was synthesized. The recombinant pcDNA3.4-LRRC15 plasmid was constructed and transfected into HEK293 cells to express the LRRC15 protein. In addition, the LRRC15 protein was characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting.@*RESULTS@#The recombinant pcDNA3.4-LRRC15 plasmid was successfully constructed, which expressed the target LRRC15 protein with an approximately molecular weight of 70 kDa. Bioinformatics prediction with the ExPASy-PortParam software showed that LRRC15 was a hydrophilic protein, which was consisted of 644 amino acids and had a molecular weight of 69.89 kDa and an isoelectric point of 5.6. The molecular formula of the LRRC15 protein was C3073H4942N846O953S28 and had an instability coefficient is 50.3, indicating that LRRC15 was an instable protein. Bioinformatics prediction with the Protean software showed that the dominant T-cell antigen epitopes were located in 292 to 295, 353 to 361, 521 to 526 and 555 to 564 amino acids of the LRRC15 protein, and the T-cell antigen epitopes with a high hydrophilicity, good flexibility, high surface accessibility and high antigenicity index were found in 122 to 131, 216 to 233, 249 to 254, 333 to 343, 358 to 361, 368 to 372, 384 to 386, 407 to 412, 445 to 450, 469 to 481, 553 to 564, 588 to 594, 607 to 617 and 624 to 639 amino acids. Following transfection of the recombinant pcDNA3.4-LRRC15 plasmid into HEK293 cells, SDS-PAGE and Western blotting identified LRRC15 proteins in cell secretory culture media, cell lysis supernatants and sediments. The LRRC15-His fusion protein was purified from the cell culture medium, and SDS-PAGE identified a remarkable band at approximately 70 kDa, while Western blotting successfully recognized the band of the recombinant LRRC15 protein.@*CONCLUSIONS@#The eukaryotic expression and antigen epitope prediction of the LRRC15 protein in the excretory secretory antigens of T. solium cysticercus have been successfully performed, which provides insights into further understandings of its biological functions.

Anti-pseudo-allergic components in licorice extract inhibit mast cell degranulation and calcium influx / 中国天然药物

Pseudo-allergic reactions (PARs) widely occur upon application of drugs or functional foods. Anti-pseudo-allergic ingredients from natural products have attracted much attention. This study aimed to investigate anti-pseudo-allergic compounds in licorice. The anti-pseudo-allergic effect of licorice extract was evaluated in rat basophilic leukemia 2H3 (RBL-2H3) cells. Anti-pseudo-allergic compounds were screened by using RBL-2H3 cell extraction and the effects of target components were verified further in RBL-2H3 cells, mouse peritoneal mast cells (MPMCs) and mice. Molecular docking and human MRGPRX2-expressing HEK293T cells (MRGPRX2-HEK293T cells) extraction were performed to determine the potential ligands of MAS-related G protein-coupled receptor-X2 (MRGPRX2), a pivotal target for PARs. Glycyrrhizic acid (GA) and licorice chalcone A (LA) were screened and shown to inhibit Compound48/80-induced degranulation and calcium influx in RBL-2H3 cells. GA and LA also inhibited degranulation in MPMCs and increase of histamine and TNF-α in mice. LA could bind to MRGPRX2, as determined by molecular docking and MRGPRX2-HEK293T cell extraction. Our study provides a strong rationale for using GA and LA as novel treatment options for PARs. LA is a potential ligand of MRGPRX2.

Construction and identification of a HEK293 cell line with stable TrxR1 overexpression / 南方医科大学学报

OBJECTIVE@#To construct a HEK293 cell line stably overexpressing TrxR1 as a cell model for functional study of TrxR1 and screening of TrxR1-targeting drugs.@*METHODS@#TrxR1 gene was amplified by PCR and ligated with the lentivirus expression vector pLVX-Puro, which was transformed into Escherichia coli and identified by Sanger dideoxy sequencing. HEK293 cells were infected with the recombinant lentivirus vector (pLVX-Puro-TXNRD1) and screened with Puromycin for cell clones with stable TrxR1 overexpression (HEK293-TrxR1-OE cells). HEK293-TrxR1-OE cells, along with HEK293 cells infected with pLVX-Puro vector (HEK293-NC) and normal HEK293 cells, were tested for mRNA and protein expression levels of TrxR1 using RT-qPCR and Western blotting. TrxR1 enzyme activity in the cells was evaluated with insulin endpoint assay and TRFS-green probe imaging. The sensitivity of the cells to auranofin, a specific TrxR1 inhibitor, was determined with CCK8 assay.@*RESULTS@#TrxR1 gene was successfully inserted into the lentiviral vector pLVX-Puro as confirmed by DNA sequencing. The enzyme activity and mRNA and protein expression levels of TrxR1 were significantly higher in HEK293-TrxR1-OE cells than in HEK293 and HEK293-NC cells (P < 0.005). The inhibitory effects of auranofin on proliferation and cellular TrxR1 enzyme activity were significantly attenuated in HEK293-TrxR1-OE cells as compared with HEK293 and HEK293-NC cells (P < 0.005).@*CONCLUSION@#We successfully obtained a HEK293 cell line with stable TrxR1 overexpression, which shows resistance to auranofin and can be used for screening TrxR1 targeting drugs.

TRIM21 suppresses invasion of hepatocellular carcinoma cells by promoting β-catenin ubiquitylation and degradation / 南方医科大学学报

OBJECTIVE@#To explore the role of TRIM21 in modulating the invasive phenotype of hepatocellular carcinoma (HCC) cells and its mechanism of action.@*METHODS@#RNA interference technique was used to knock down the expression of TRIM21 and β-catenin, alone or in combination, in HCC cell lines 97H and LM3, and the interfering efficiency and the activity of closely related pathways were determined using Western blotting. The two cells with TRIM21 knockdown (siTRIM21 97H and siTRIM21 LM3 cells) were assessed for their invasion ability in vitro using Transwell invasion assay, and the lung metastasis capacity of siTRIM21 LM3 cells following tail vein injection was evaluated in nude mice. The binding of TRIM21 with β-catenin and the ubiquitylation level of β-catenin in TRIM21-overexpressing HEK293 cells were determined with Western blotting and co-immunoprecipitation assay. We also compared the overall survival of patients with CTNNB1highTRIM21high and CTNNB1highTRIM21low HCC subtypes using Kaplan-Meier method based on filtrated and grouped HCC clinical data from TCGA database.@*RESULTS@#TRIM21 knockdown significantly enhanced the invasion ability of 97H and LM3 cells in vitro (P < 0.01 or 0.05) and the lung metastasis ability of LM3 cells in nude mice (P < 0.01), and simultaneous knockdown of β -catenin obviously suppressed the in vitro invasiveness of the cells (P < 0.0001 or 0.05). Co-immunoprecipitation assay showed that TRIM21 was capable of directly binding with β-catenin protein to accelerate the ubiquitination and degradation of the latter, leading to inhibition of nuclear translocation of β-catenin and hence reduced invasiveness of HCC cells. Bioinformatic analysis showed that compared patients with CTNNB1highTRIM21low HCC subtype where Wnt pathway was activated, the patients with CTNNB1highTRIM21high HCC subtype had a significantly better survival outcomes (P < 0.05).@*CONCLUSION@#A high expression of TRIM21 suppresses the invasion of HCC cells by promoting β-catenin ubiquitylation and degradation, which possibly explains the poor prognosis of CTNNB1highTRIM21low HCC patients.

β-arrestin2 recruitment by β-adrenergic receptor agonists and antagonists / 生理学报

A large number of β-adrenergic receptor (β-AR) agonists and antagonists are widely used in the treatment of cardiovascular diseases and other diseases. Nonetheless, it remains unclear whether these commonly used β-AR drugs can activate downstream β- arrestin-biased signaling pathways. The objective of this study was to investigate β-arrestin2 recruitment effects of β-AR agonists and antagonists that were commonly used in clinical practice. We used TANGO (transcriptional activation following arrestin translocation) assay to detect the β-arrestin2 recruitment by β-AR ligands in HEK293 cell line (HTLA cells) stably transfected with tetracycline transactivator protein (tTA) dependent luciferase reporter and β-arrestin2-TEV fusion gene. Upon activation of β-AR by a β-AR ligand, β-arrestin2 was recruited to the C terminus of the receptor, followed by cleavage of the G protein-coupled receptors (GPCRs) fusion protein at the TEV protease-cleavage site. The cleavage resulted in the release of tTA, which, after being transported to the nucleus, activated transcription of the luciferase reporter gene. The results showed that β-AR non-selective agonists epinephrine, noradrenaline and isoprenaline all promoted β-arrestin2 recruitment at β1-AR and β2-AR. β1-AR selective agonists dobutamine and denopamine both promoted β-arrestin2 recruitment at β1-AR. β2-AR selective agonists procaterol and salbutamol promoted β-arrestin2 recruitment at β2-AR. β-AR non-selective antagonists alprenolol and pindolol promoted β-arrestin2 recruitment at β1-AR. β1-AR selective antagonists celiprolol and bevantolol showed β-arrestin2 recruitment at β1-AR. β2-AR selective antagonists butoxamine showed β-arrestin2 recruitment at β1-AR. These results provide some clues for the potential action of β-AR drugs, and lay a foundation for the screening of β-arrestin-biased β-AR ligands.

Assessment of Antioxidant and Cytotoxic Activities and Identification of Phenolic Compounds of Centaurea solstitialis and Urospermum picroides from Turkey

HIGHLIGHTS The phenolic composition, antioxidant activity and cytotoxic potential of the extracts of C. solstitialis and U. picroides were investigated. Caffeic acid was found as the most abundant phenolic compound in the extracts. Both species showed promising antioxidant activity towards different assays. The highest cytotoxic potential was observed in the extract of C. solstitialis.

Abstract It is known that some genera of the Asteraceae family are commonly used in Turkish folk medicine. Several studies have investigated the biological effects of different extracts of Centaurea and Urospermum species, but studies involving the phenolic composition of C. solstitialis and U. picroides extracts are very limited. This study aimed to investigate the phenolic composition and antioxidant activity of C. solstitialis and U. picroides and evaluate their possible cytotoxic effect. RP-HPLC analysis was used to elucidate the phenolic profiles of the ethanolic extracts of flowering parts of C. solstitialis and U. picroides.The both ethanolic extracts were assessed for their antioxidant properties using DPPH, FRAP, phosphomolybdenum and metal chelating assays. Furthermore, the effect of the extracts on cell viability was evaluated against MCF-7 and PC-3 cancer cells and HEK293 cell line using the MTT assay. The most abundant phenolic compound in both extracts was determined to be caffeic acid, and the amount of this compound was 24078.03 and 14329.59 µg g-1 in the extracts of C. solstitialis and U. picroides, respectively. The antioxidant activity of the extracts was found similar. Compared with U. picroides extract, C. solstitialis extract had higher potential on the inhibition of cell viability. The IC50 value of C. solstitialis on MCF cells was found as 58.53 µg mL-1. These data suggest that the extracts of C. solstitialis and U. picroides may be considered as novel and alternative natural antioxidant and anticancer sources.