GLP-1 attenuates Ang II-induced proliferation and migration in rat aorta smooth muscle cells via inhibition of the RhoA/ROCK2 signaling pathway.

Glucagon-like peptide 1 (GLP-1), a neuroendocrine hormone produced by the gastrointestinal tract, plays a significant role in blood glucose regulation; drugs derived from GLP-1 are currently used for the treatment of type 2 diabetes. In addition to regulating glucose homeostasis, the protective effects of GLP-1 on the cardiovascular system are also of interest. However, the vascular protective mechanisms of GLP-1 remain unclear. The present study was designed to evaluate the role of GLP-1 in the proliferation and migration of vascular smooth muscle cells, and the underlying mechanisms. In this study, proliferation, migration, cyclin D1 expression, and phosphorylation of MLC, as well as RhoA and Rho-associated coiled-coil forming protein kinase 2 (ROCK2) expression, were increased in rat aorta smooth muscle cells (RASMCs) following incubation with angiotensin II (Ang II). These effects were significantly attenuated by GLP-1, forskolin (a cAMP activator) and Y-27632 (a ROCK2 inhibitor). However, H89 (a PKA inhibitor) inhibited the action of GLP-1, both in terms of inhibition of RASMC proliferation and migration, and RHOA/ROCK2 expression. These results indicate that GLP-1 inhibits Ang II-induced RASMC proliferation and migration via the cAMP/PKA/RhoA/ROCK2 signaling pathway. Our data suggest that GLP-1 should be considered for use in the clinical treatment of cardiovascular diseases, in addition to its current use in the treatment of diabetes mellitus.

Investigating the Role of the Posttranscriptional Gene Regulator MiR-24- 3p in the Proliferation, Migration and Apoptosis of Human Arterial Smooth Muscle Cells in Arteriosclerosis Obliterans.

AIMS: To explore the expression of miR-24-3p in human arteries with arteriosclerosis obliterans (ASO) as well as the role of miR-24-3p in the pathogenesis of ASO. METHODS: We used quantitative real-time PCR (qRT-PCR) and in situ hybridization to monitor miR-24-3p expression in human arteries. To investigate the effect of miR-24-3p on human arterial smooth muscle cells (HASMCs), we applied cell counting and EdU assays to monitor proliferation and transwell and wound healing assays to investigate migration and flow cytometry to investigate apoptosis. Furthermore, we applied 3'-untranslated region (3'-UTR) luciferase assays to investigate the role of miR-24-3p in targeting platelet-derived growth factor receptor B (PDGFRB) and c-Myc. RESULTS: MiR-24-3p was mainly located in the media of arteries and was downregulated in ASO arteries compared with normal arteries. Platelet-derived growth factor BB (PDGF-BB) treatment reduced the expression of miR-24-3p in primary cultured HASMCs. MiR-24-3p mimic oligos inhibited the proliferation and migration, and promotes apoptosis of HASMCs. Our 3'-UTR luciferase assays confirmed that PDGFRB and c-Myc were targets of miR-24-3p. CONCLUSION: The results suggest that miR-24-3p regulates the proliferation and migration of HASMCs by targeting PDGFRB and c-Myc. The PDGF/miR-24-3p/PDGFRB and PDGF/miR-24-3p/c-Myc pathways may play critical roles in the pathogenesis of ASO. These findings highlight the potential for new therapeutic targets for ASO.

Expression, purification, and characterization of alanine racemase from Pseudomonas putida YZ-26.

Alanine racemase catalyzes the interconversion of D: - and L: -alanine and plays an important role in supplying D: -alanine, a component of peptidoglycan biosynthesis, to most bacteria. Alanine racemase exists mostly in prokaryotes and is generally absent in higher eukaryotes; this makes it an attractive target for the design of new antibacterial drugs. Here, we present the cloning and characterization of a new gene-encoding alanine racemase from Pseudomonas putida YZ-26. An open reading frame (ORF) of 1,230 bp, encoding a protein of 410 amino acids with a calculated molecular weight of 44,217.3 Da, was cloned into modified vector pET32M to form the recombinant plasmid pET-alr. After introduction into E.coli BL21, the strain pET-alr/E.coli BL21 expressed His(6)-tagged alanine racemase. The recombinant alanine racemase was efficiently purified to homogeneity using Ni(2+)-NTA and a gel filtration column, with 82.5% activity recovery. The amino acid sequence deduced from the alanine racemase gene revealed identity similarities of 97.0, 93, 23, and 22.0% with from P. putida F1, P. putida200, P. aeruginosa, and Salmonella typhimurium, respectively. The recombinant alanine racemase is a monomeric protein with a molecular mass of 43 kDa. The enzyme exhibited activity with L: -alanine and L: -isoleucine, and showed higher specificity for the former compared with the latter. The enzyme was stable from pH 7.0-11.0; its optimum pH was at 9.0. The optimum temperature for the enzyme was 37°C, and its activity was rapidly lost at temperatures above 40°C. Divalent metals, including Sr(2+), Mn(2+), Co(2+), and Ni(2+) obviously enhanced enzymatic activity, while the Cu(2+) ion showed inhibitory effects.

Malignant adenomyoepithelioma of the breast: Two case reports and review of the literature.

BACKGROUND: Malignant adenomyoepithelioma (AME) of the breast is a rare tumor in which malignancy can arise from either epithelial or myoepithelial components, or from both cell types. The incidence and prognosis of malignant AME of the breast are difficult to assess due to its rarity. Therefore, the optimal treatment for this disease is still controversial. CASE SUMMARY: We present two middle-aged women (48 and 56 years old) with malignant AME of the breast. Core needle biopsy was performed before surgery. However, breast adenoma and malignant tumors were observed. The preoperative diagnosis of malignant AME of the breast is still challenging for pathologists and clinicians. Both patients underwent mastectomy and sentinel lymph node biopsy, both of which were negative, followed by adjuvant chemotherapy. CONCLUSION: The follow-up duration of the two patients was two years and four months, respectively. No signs of relapse or metastasis have been observed thus far.

Characterization of zinc-binding properties of a novel imidase from Pseudomonas putida YZ-26.

The imidase from Pseudomonas putida YZ-26 consisting of 293-amino acid residues is a novel imidase with four subunits as the holo-enzyme and low molecular weight which is significantly different from known mammalian imidase. This study measured the zinc-binding properties of the imidase using inductively coupled plasma-atomic emission spectrometry and competition assay combined with activity determinations. Results show that each subunit of the imidase binds the zinc ion by 1:1 stoichiometry with apparent binding constant of 9.5 x 10(8)M(-1). The activity of the apo-imidase (20 microM) was recovered with the addition of zinc in the lower concentration (0-20 microM), whereas the enzymatic activity is decreased in the presence of high concentration of zinc (above 100 microM). The site-directed mutagenesis of His(247), His(86) or Cys(7), Cys(108) in imidase resulted in loss of activity and zinc-binding abilities at different degrees, showing that these residues may critically affect both enzymatic activity and conformation.

Glucagon-like peptide 1 treatment reverses vascular remodelling by downregulating matrix metalloproteinase 1 expression through inhibition of the ERK1/2/NF-κB signalling pathway.

In addition to serving as an incretin-based treatment of type 2 diabetes mellitus (T2DM), glucagon-like peptide 1 (GLP-1) can also reverse cardiovascular diseases caused by vascular remodelling. However, a detailed mechanism underlying how GLP-1 reverses vascular remodelling remains unclear. Here, Spontaneous hypertension rats (SHR) were used as an in vivo model of vascular remodelling. Treatment with a GLP-1 receptor (GLP-1R) agonist Liraglutide or dipeptidyl peptidase 4 (DPP4) inhibitor Alogliptin decreased systolic blood pressure (SBP), diastolic blood pressure (DBP), thickness of vascular wall, and overall collagen levels in SHR. In vitro vascular remodelling can be induced by exposing rat aortic smooth muscle cells (RASMC) to angiotensin II (Ang II); GLP-1 treatment attenuated AngII induction of RASMC proliferation, migration, and excessive extracellular matrix (ECM) degradation. Downregulation of matrix metalloproteinase 1 (MMP1) enhanced the inhibitory effects of GLP-1, and extracellular regulated protein kinase 1/2 (ERK1/2) and nuclear factor kappa-B (NF-κB) signalling participated in these processes. These results provide a new mechanistic understanding of key therapeutic strategies for the treatment of vascular remodelling-related diseases.

[Expression of transcription factor T-bet and GATA-3 in peripheral blood mononuclear cells and its correlation with immune status in esophageal cancer patients].

OBJECTIVE: To investigate the expression of transcription factors (TF) T-bet and GATA-3 mRNA in peripheral blood mononuclear cells and its correlation with immune status in esophageal cancer patients. METHODS: Sixty patients were divided into two groups according to the clinical data: group A consisting of stage I and II, group B including stage III and IV. The gene expression of T-bet and GATA-3 in 60 esophageal cancer patients and 30 healthy controls was detected by reverse transcription-polymerase chain reaction (RT-PCR). The expression of IFN-gamma and IL-4 was measured by enzyme linked immunosorbent assay (ELISA). RESULTS: Expression of T-bet mRNA in esophageal cancer patients (stage I and II: 0.27 +/- 0.05 ng/L, stage III and IV: 0.12 +/- 0.02 ng/L) was significantly lower than that in the healthy controls (1.35 +/- 0.14 ng/L), but the expression of GATA-3 mRNA in esophageal cancer patients (stage I and II: 0.45 +/- 0.06, stage III and IV: 0.55 +/- 0.03) was significantly higher than that in the healthy controls (0.09 +/- 0.10). The plasma level of Th1 cytokine IFN-gamma in the patients [stage I and II: (12.12 +/- 1.48) ng/L, stage III and IV: (8.44 +/- 0.90) ng/L] was significantly lower than that in the healthy controls, while the level of Th2 cytokine IL-4 in the patients [stage I and II: (18.64 +/- 0.77) ng/L, stage III and IV: (25.28 +/- 2.02) ng/L] was significantly higher than that in the healthy controls. However, neither in the expression of T-bet and GATA-3, nor in the plasma level of IFN-gamma and IL-4, showed a significant difference between group A and B. CONCLUSION: In the peripheral blood of esophageal cancer patients, the expression of T-bet decreased, while GATA-3 increased, Th1/Th2 balance is broken, and the Th2 is dominant. T-bet and GATA-3 play a part role in the regulation of Th1/Th2 balance.

GLP-1 Relaxes Rat Coronary Arteries by Enhancing ATP-Sensitive Potassium Channel Currents.

GLP-1 is a new type of antidiabetic agent that possesses many beneficial effects. Although its cardiovascular actions have been widely examined, little is known about GLP-1's effects on the rat coronary artery (RCA) or about the mechanisms underpinning these effects. Here, we report that GLP-1 inhibits depolarization- or thromboxane receptor agonist (U46619)-induced RCA contraction in a dosage-dependent manner. Vasorelaxation was attenuated by denuding the endothelium, L-NAME (nitric oxide synthase inhibitor), and glyburide (KATP channel blocker) but was not affected by indomethacin (cyclooxygenase inhibitor), iberiotoxin [Ca2+-activated K+ channel (KCa) blocker], or 4-aminopyridine (KV channel blocker). Furthermore, GLP-1 increased outward K+ currents by enhancing the KATP channel in rat coronary arterial smooth muscle cells (RCASMCs). These results show that GLP-1 is an endothelial-dependent vasospasmolytic agent in the RCA and imply that the relaxant effect is regulated by enhancing KATP rather than KV or KCa currents in RCASMCs.

The flexibility of the non-conservative region at the C terminus of D-hydantoinase from Pseudomonas putida YZ-26 is extremely limited.

We previously reported that a deletion mutant (P478) with a residue Arg deleted at the C terminus of D-hydantoinase (P479) from Pseudomonas putida YZ-26 was dissociated into the monomer from its dimeric state. Based on the above result, a series of mutants of the enzyme with the C-terminal residues either deleted or substituted were prepared. The size-exclusion chromatography and bioactivity assay show that a C-terminal-substituted enzyme (R479D) and several truncated mutants (P478, P477, P476, and P475) are dissociated into the monomeric state as well, but their activities are largely retained. In contrast, two other mutants (R474 and R479A) are expressed in the form of random aggregates without any activity. Our experiments demonstrate that only the last four amino acids (-PVQR) at the C terminus of the enzyme can be deleted without seriously affecting its activity, although the enzyme is dissociated from a dimer into a monomer. These mutants also reveal some unique properties such as the enzymatic activity in vivo or in vitro, the effect of divalent metal ions, and the thermostability etc. in comparison to wild-type enzyme (P479). In addition, the three-dimensional structural modeling shows that the intact structure of the enzyme is essential, and the flexibility of the non-conservative region at the C terminus of the enzyme is quite limited.

A single pH fluorescent probe for biosensing and imaging of extreme acidity and extreme alkalinity.

A simple tailor-made pH fluorescent probe 2-benzothiazole (N-ethylcarbazole-3-yl) hydrazone (Probe) is facilely synthesized by the condensation reaction of 2-hydrazinobenzothiazole with N-ethylcarbazole-3-formaldehyde, which is a useful fluorescent probe for monitoring extremely acidic and alkaline pH, quantitatively. The pH titrations indicate that Probe displays a remarkable emission enhancement with a pKa of 2.73 and responds linearly to minor pH fluctuations within the extremely acidic range of 2.21-3.30. Interestingly, Probe also exhibits strong pH-dependent characteristics with pKa 11.28 and linear response to extreme-alkalinity range of 10.41-12.43. In addition, Probe shows a large Stokes shift of 84 nm under extremely acidic and alkaline conditions, high selectivity, excellent sensitivity, good water-solubility and fine stability, all of which are favorable for intracellular pH imaging. The probe is further successfully applied to image extremely acidic and alkaline pH values fluctuations in E. coli cells.

[Molecular form and stability of D-hydantoinase deleted at C-terminal residue Arg].

This report is about only deleting one C-terminal residue of D-hydantoinase to result in obvious changes on its molecular form and stability. A recombinant D-hydantoinase (P479) and its mutant enzyme deleted at C-terminal residue Arg (P478) were prepared by methods of gene cloning, expression and purification. Results show that the subunit molecular weight of P479 and P478 is the same (54kDa) as determined by SDS-PAGE, whilst the molecular form of native P479 and P478 is a dimer and a monomer respectively in the completely operative conditions. Compared with P479, the enzymatic activity of P478 for substrate hydantoin maintained about 40% and pH stability was obviously increased, at the alkaline side in particular, as well as the anti-SDS ability was also raised. However, the thermal stability for P478 was clearly lowed as compared to P479. It implies from above data that the C-terminal residue Arg of the D-hydantoinase is a crucial one for subunit dissociation, but non-essential for catalysis.

High mobility group-box 3 overexpression is associated with poor prognosis of resected gastric adenocarcinoma.

AIM: To elucidate high mobility group-box 3 (HMGB3) protein expression in gastric adenocarcinoma, its potential prognostic relevance, and possible mechanism of action. METHODS: Ninety-two patients with gastric adenocarcinomas surgically removed entered the study. HMGB3 expression was determined by immunohistochemistry through a tissue microarray procedure. The clinicopathologic characteristics of all patients were recorded, and regular follow-up was made for all patients. The inter-relationship of HMGB3 expression with histological and clinical factors was analyzed using nonparametric tests. Survival analysis was carried out by Kaplan-Meier (log-rank) and multivariate Cox (Forward LR) analyses between the group with overexpression of HMGB3 and the group with low or no HMGB3 expression to determine the prognosis value of HMGB3 expression on overall survival. Further, HMGB3 expression was knocked down by small hairpin RNAs (shRNAs) in the human gastric cancer cell line BGC823 to observe its influence on cell biological characteristics. The MTT method was utilized to detect gastric cancer cell proliferation changes, and cell cycle distribution was analyzed by flow cytometry. RESULTS: Among 92 patients with gastric adenocarcinomas surgically removed in this study, high HMGB3 protein expression was detected in the gastric adenocarcinoma tissues vs peritumoral tissues (P < 0.001). Further correlation analysis with patients' clinical and histology variables revealed that HMGB3 overexpression was obviously associated with extensive wall penetration (P = 0.005), a positive nodal status (P = 0.004), and advanced tumor-node-metastasis (TNM) stage (P = 0.001). But there was no correlation between HMGB3 overexpression and the age and gender of the patient, tumor localization or histologic grade. Statistical Kaplan-Meier survival analysis disclosed significant differences in overall survival between the HMGB3 overexpression group and the HMGB3 no or low expression group (P = 0.006). The expected overall survival time was 31.00 ± 3.773 mo (95%CI = 23.605-38.395) for patients with HMGB3 overexpression and 49.074 ± 3.648 mo (95%CI = 41.925-57.311) for patients with HMGB3 no and low-level expression. Additionally, older age (P = 0.040), extensive wall penetration (P = 0.008), positive lymph node metastasis (P = 0.005), and advanced TNM tumor stage (P = 0.007) showed negative correlation with overall survival. Multivariate Cox regression analysis indicated that HMGB3 overexpression was an independent variable with respect to age, gender, histologic grade, extent of wall penetration, lymph nodal metastasis, and TNM stage for patients with resectable gastric adenocarcinomas with poor prognosis (hazard ratio = 2.791, 95%CI = 1.233-6.319, P = 0.019). In the gene function study, after HMGB3 was knocked down in the gastric cell line BGC823 by shRNA, the cell proliferation rate was reduced at 24 h, 48 h and 72 h. Compared to BGC823 shRNA-negative control (NC) cells, the cell proliferation rate in cells that had HMGB3 shRNA transfected was significantly decreased (P < 0.01). Finally, cell cycle analysis by FACS showed that BGC823 cells that had HMGB3 knocked down were blocked in G1/G0 phase. The percentage of cells in G1/G0 phase in BGC823 cells with shRNA-NC and with shRNA-HMGB3 was 46.84% ± 1.7%, and 73.03% ± 3.51% respectively (P = 0.001), whereas G2/M cells percentage decreased from 26.51% ± 0.83% to 17.8% ± 2.26%. CONCLUSION: HMGB3 is likely to be a useful prognostic marker involved in gastric cancer disease onset and progression by regulating the cell cycle.

Gene cloning, expression, and substrate specificity of an imidase from the strain Pseudomonas putida YZ-26.

A gene-encoding imidase was isolated from Pseudomonas putdia YZ-26 genomic DNA using a combination of polymerase chain reaction and activity screening the recombinant. Analysis of the nucleotide sequence revealed that an open reading frame (ORF) of 879 bp encoded a protein of 293 amino acids with a calculated molecular weight of 33712.6 kDa. The deduced amino-acid sequence showed 78% identity with the imidase from Alcaligenes eutrophus 112R4 and 80% identity with N-terminal 20 amino-acid imidase from Blastobacter sp. A17p-4. Next, the ORF was subcloned into vector pET32a to form recombinant plasmid pEI. The enzyme was overexpressed in Escherichia coli and purified to homogeneity by Ni(2+)-NTA column, with 75% activity recovery. The subunit molecular mass of the recombinant imidase as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was approximately 36 kDa, whereas its functional unit was approximately 141 kDa with four identical subunits determined by size-exclusion chromatography. The purified enzyme showed the highest activity and affinity toward succinimide, and some other substrates, such as dihydrouracil, hydantoin, succinimide, and maleimde, were investigated.

PDZ7 of glutamate receptor interacting protein binds to its target via a novel hydrophobic surface area.

Glutamate receptor interacting protein 1 (GRIP1) is a scaffold protein composed of seven PDZ (Postsynaptic synaptic density-95/Discs large/Zona occludens-1) domains. The protein plays important roles in the synaptic targeting of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. The interaction between GRIP1 PDZ7 and a Ras guanine nucleotide exchange factor, GRASP-1, regulates synaptic distribution of AMPA receptors. Here, we describe the three-dimensional structure of GRIP1 PDZ7 determined by NMR spectroscopy. GRIP1 PDZ7 contains a closed carboxyl group-binding pocket and a narrow alphaB/betaB-groove that is not likely to bind to classical PDZ ligands. Unexpectedly, GRIP1 PDZ7 contains a large solvent-exposed hydrophobic surface at a site distinct from the conventional ligand-binding alphaB/betaB-groove. NMR titration experiments show that GRIP1 PDZ7 binds to GRASP-1 via this hydrophobic surface. Our data uncover a novel PDZ domain-mediated protein interaction mode that may be responsible for multimerization of other PDZ domain-containing scaffold proteins.