Bacterial Proteins/metabolism* ; Operon/genetics* ; Phosphotransferases/metabolism* ; Quorum Sensing/genetics* ; Vibrio cholerae/genetics*

Polyphosphate kinase plays an important role in the catalytic synthesis of ATP in vitro. In order to find a polyphosphate kinase that can efficiently synthesize ATP using short-chain polyphosphate (polyP) as substrate, the polyphosphate kinase 2 (PPK2) from Sphingobacterium siyangensis was cloned and expressed in Escherichia coli BL21(DE3). As an enzyme for ATP regeneration, PPK2 was used in combination with l-amino acid ligase (YwfE) to produce l-alanyl-l-glutamine (Ala-Gln). The length of ppk2 of S. siyangensis is 810 bp, encoding 270 amino acids. The SDS-PAGE showed that PPK2 was expressed correctly and its molecular weight was 29.7 kDa as expected. The reaction conditions of PPK2 were optimized. PPK2 could maintain good activity in the range of 22-42 ℃ and pH 7-10. The highest enzyme activity was observed at 37 ℃, pH 7, 30 mmol/L magnesium ion (Mg²⁺), 5 mmol/L ADP and 10 mmol/L sodium hexametaphosphate, and the yield of ATP reached 60% of the theoretical value in 0.5 hours at this condition. When used in combination with YwfE to produce Ala-Gln, the PPK2 showed a good applicability as an ATP regeneration system, and the effect was similar to that of direct addition of ATP. The PPK2 from S. siyangensis shows good performance in a wide range of temperature and pH, synthesizes ATP with cheap and readily available short chain polyP as substrate. The PPK2 thus provides a new enzyme source for ATP dependent catalytic reaction system.
Sphingobacterium/metabolism* ; Phosphotransferases (Phosphate Group Acceptor)/metabolism* ; Amino Acids ; Adenosine Triphosphate ; Regeneration ; Polyphosphates/metabolism*

The purpose of the present study was to investigate the effect and potential mechanism of knockdown of sphingosine kinase-1 (SPHK1) on the proliferation, cell cycle and apoptosis of non-small cell lung cancer (NSCLC) cells. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect SPHK1 mRNA expression in human healthy lung fibroblasts (MRC-5 cells) and four NSCLC cell lines. Then, A549 and H1299 cells were transfected with SPHK1-shRNA and corresponding negative control. CCK-8, Annexin V-FITC/PI dual staining and cell cycle assay were performed to evaluate cell proliferation, apoptosis and cell cycle distribution, respectively. JC-1 mitochondrial membrane potential measurement kit was adopted to measure mitochondrial membrane potential. Western blot was used to detect the protein expression levels of cell cycle and mitochondrial apoptotic pathway-related proteins, as well as MEK/ERK signaling pathway. The results showed that the mRNA expression of SPHK1 in NSCLC cells was higher than that in MRC-5 cells. SPHK1-shRNA significantly inhibited the proliferation of A549 and H1299 cells, blocked the cell cycle in G0/G1 phase, and promoted cell apoptosis through the mitochondrial pathway. Compared with the control group, the expression of p-MEK and p-ERK proteins in the SPHK1-shRNA group was significantly down-regulated. Moreover, MEK/ERK inhibitor could dramatically suppress cell proliferation and promote cell apoptosis. These results suggest that SPHK1 knockdown can inhibit the proliferation of NSCLC cells and might promote mitochondrial apoptotic pathway by inhibiting MEK/ERK signaling pathway.
Apoptosis ; Carcinoma, Non-Small-Cell Lung/genetics* ; Cell Line, Tumor ; Cell Proliferation ; Gene Knockdown Techniques ; Humans ; Lung Neoplasms/genetics* ; Phosphotransferases (Alcohol Group Acceptor)/genetics*

Uridine-cytidine kinase, an important catalyst in the compensation pathway of nucleotide metabolism, can catalyze the phosphorylation reaction of cytidine to 5'-cytidine monophosphate (CMP), but the reaction needs NTP as the phosphate donor. To increase the production efficiency of CMP, uridine-cytidine kinase gene from Thermus thermophilus HB8 and polyphosphate kinase gene from Rhodobacter sphaeroides were cloned and expressed in Escherichia coli BL21(DE3). Uridine-cytidine kinase was used for the generation of CMP from cytidine and ATP, and polyphosphate kinase was used for the regeneration of ATP. Then, the D403 metal chelate resin was used to adsorb Ni²⁺ to form an immobilized carrier, and the immobilized carrier was specifically combined with the recombinant enzymes to form the immobilized enzymes. Finally, single-factor optimization experiment was carried out to determine the reaction conditions of the immobilized enzyme. At 30 °C and pH 8.0, 60 mmol/L cytidine and 0.5 mmol/L ATP were used as substrates to achieve 5 batches of high-efficiency continuous catalytic reaction, and the average molar yield of CMP reached 91.2%. The above method has the advantages of low reaction cost, high product yield and high enzyme utilization rate, and has good applied value for industrial production.
Cytidine Monophosphate ; metabolism ; Escherichia coli ; genetics ; Industrial Microbiology ; methods ; Phosphotransferases (Phosphate Group Acceptor) ; metabolism ; Uridine Kinase

Objective To investigate the therapeutic effect of SPK1 gene transfected adipose derived mesenchymal stem cells(ADMSC)on experimental autoimmune encephalomyelitis mice and the effect on T helper cell 17(Th17)/regulatory T(Treg) cells balance. Methods EAE was induced by myelin oligodendrocyte glycoprotein 35-55 in mice.Totally 44 mice were randomly divided into four groups:normal control group(NC group),model group(EAE group),ADMSC group,and ADMSC-SPK1 group.Forty days after injection,the pathological changes of brain and spinal cord,Th17/Treg-related inflammatory markers in brain tissue,expressions of interleukin-17A(IL-17A)and forkhead box protein p3(Foxp3)in brain and spinal cord tissue,and flow cytometric results of spleen immune cells were detected. Results Forty days after the injection,serious inflammatory cell infiltration and demyelination occurred in the brain and spinal cord of EAE group,whereas demyelination and axonal injury were improved in ADMSC group and ADMSC-SPK1 group.Compared with EAE group,the ADMSC group and ADMSC-SPK1 group had significantly improved levels of IL-17A(
Adipose Tissue/cytology* ; Animals ; Cytokines ; Encephalomyelitis, Autoimmune, Experimental/therapy* ; Interleukin-17 ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stem Cells/cytology* ; Mice ; Mice, Inbred C57BL ; Phosphotransferases (Alcohol Group Acceptor)/genetics* ; T-Lymphocytes, Regulatory/cytology* ; Th17 Cells/cytology* ; Transfection

Adenocarcinoma ; Carcinoma, Non-Small-Cell Lung ; Constriction ; Humans ; Immunohistochemistry ; Lung ; Methods ; Phosphotransferases ; Receptor, Epidermal Growth Factor

Immunotherapy ; Lung Neoplasms ; Lung ; Lymphoma ; Phosphotransferases ; Prognosis ; Protein-Tyrosine Kinases ; Receptor, Epidermal Growth Factor

PURPOSE: Phosphoinositide 3-kinase (PI3K)-δ-dependent Akt activation is known to play critical roles in various immune responses of white blood cells in which PI3K-δ isoform is mostly expressed in contrast to the classes IA PI3Ks p110α and p110β. However, the immunological role of PI3K-δ isoform is still controversial in airway epithelium under house dust mite (HDM)-induced allergic response. This study aimed to evaluate the role of PI3K-δ isoform in HDM-induced allergic responses, focusing on NLRP3 inflammasome activation in airway epithelium.METHODS: We used wild-type mice and PI3K-δ knock-out (KO) mice for HDM-induced asthma animal model and also performed in vitro experiments using primary cultured murine tracheal epithelial cells and human airway epithelial cells.RESULTS: PI3K-δ activated HDM-induced NLRP3 inflammasome and epithelial cell-derived cytokines in the lung including airway epithelial cells. PI3K-δ KO mice or knock-down of PI3K-δ using siRNA exhibited the significant reduction in allergic asthmatic features and the suppression of NLRP3 inflammasome assembly as well as epithelial cell-derived cytokines. Interestingly, significantly increased expression of PI3K-δ isoform was observed in stimulated airway epithelial cells and the increases in epithelial cell-derived cytokines were markedly suppressed by blocking PI3K-δ, while these cytokine levels were independent of NLRP3 inflammasome activation.CONCLUSIONS: The results of this study suggest that PI3K-δ-isoform can promote HDM-induced allergic airway inflammation via NLRP3 inflammasome-dependent response as well as via NLRP3 inflammasome-independent epithelial cell activation.
Animals ; Asthma ; Cytokines ; Dust ; Epithelial Cells ; Epithelium ; Humans ; In Vitro Techniques ; Inflammasomes ; Inflammation ; Leukocytes ; Lung ; Mice ; Models, Animal ; Phosphotransferases ; Pyroglyphidae ; RNA, Small Interfering

PURPOSE: Plasma cells and immunoglobulins (Igs) play a pivotal role in the induction and maintenance of chronic inflammation in nasal polyps. During secondary immune responses, plasma cell survival and Ig production are regulated by the local environment. The purpose of the present study was to investigate the presence of long-lived plasma cells (LLPCs) and specific survival niches for LLPCs in human nasal polyps.METHODS: Nasal mucosal samples were cultured with an air-liquid interface system and the Ig levels in culture supernatants were analyzed by enzyme-linked immunosorbent assay. The characteristics of LLPCs in nasal polyps were determined by immunohistochemistry and immunofluorescence. The expression of neurotrophins as well as their receptors was detected by quantitative real-time polymerase chain reaction, immunohistochemistry, immunofluorescence, and Western blotting.RESULTS: The numbers of CD138⁺ total plasma cells and BCL2⁺ plasma cells were increased in both eosinophilic and non-eosinophilic nasal polyps compared with those in normal tissues. The production of IgG, IgA, and IgE was detected in culture supernatants even after a 32-day culture of nasal polyps. Although the total numbers of plasma cells were decreased in nasal polyps after culture, the numbers of BCL2⁺ plasma cells remained stable. The expression of nerve growth factor (NGF) as well as tropomyosin receptor kinase (Trk) A, a high-affinity receptor for NGF, was upregulated in both eosinophilic and non-eosinophilic nasal polyps. In addition, BCL2⁺ plasma cell numbers were positively correlated with NGF and TrkA mRNA expression in nasal mucosal tissues. Polyp plasma cells had the expression of TrkA.CONCLUSIONS: Human nasal polyps harbor a population of LLPCs and NGF may be involved in their prolonged survival. LLPCs may be a novel therapeutic target for suppressing the local Ig production in nasal polyps.
Blotting, Western ; Enzyme-Linked Immunosorbent Assay ; Eosinophils ; Fluorescent Antibody Technique ; Humans ; Immunoglobulin A ; Immunoglobulin E ; Immunoglobulin G ; Immunoglobulins ; Immunohistochemistry ; Inflammation ; Mucous Membrane ; Nasal Polyps ; Nerve Growth Factor ; Nerve Growth Factors ; Phosphotransferases ; Plasma Cells ; Plasma ; Polyps ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Tropomyosin

The ezrin-radixin-moesin (ERM) proteins are a family of membrane-associated proteins known to play roles in cell-shape determination as well as in signaling pathways. We have previously shown that amphetamine decreases phosphorylation levels of these proteins in the nucleus accumbens (NAcc), an important neuronal substrate mediating rewarding effects of drugs of abuse. In the present study, we further examined what molecular pathways may be involved in this process. By direct microinjection of LY294002, a PI3 kinase inhibitor, or of S9 peptide, a proposed GSK3β activator, into the NAcc core, we found that phosphorylation levels of ERM as well as of GSK3β in this site are simultaneously decreased. These results indicate that ERM proteins are under the regulation of Akt-GSK3β signaling pathway in the NAcc core. The present findings have a significant implication to a novel signal pathway possibly leading to structural plasticity in relation with drug addiction.
Amphetamine ; Animals ; Glycogen Synthase Kinases ; Humans ; Membrane Proteins ; Microinjections ; Negotiating ; Neurons ; Nucleus Accumbens ; Phosphorylation ; Phosphotransferases ; Plastics ; Proto-Oncogene Proteins c-akt ; Rats ; Reward ; Signal Transduction ; Street Drugs ; Substance-Related Disorders