MiR-3646 accelerates inflammatory response of Ang II-induced hVSMCs via CYP2J2/EETs axis in hypertension model

BACKGROUND

Inflammatory response of human vascular smooth muscle cells (hVSMCs) is a driving factor in hypertension progression. It has been reported that miR-3646 was significantly up-regulated in serum samples from patients with coronary artery disease and acute myocardial infarction mice. However, its role and underlying molecular mechanism related to inflammatory response of angiotensin II (Ang II)-induced hVSMCs remain unclear.

OBJECTIVE

We aimed to explore the potential molecular mechanisms related to inflammatory response of angiotensin II (Ang II)-induced hVSMCs.

METHODS

Ang II-induced hypertension model was established after hVSMCs treated with 1 μM Ang II at 24 h. The interaction between microRNA 3646 (miR-3646) and cytochrome P450 2J2 (CYP2J2) was assessed by dual-luciferase reporter gene assay. MTS assay, Lipid Peroxidation MDA Assay Kit, ELISA, Western blot, and qRT-PCR were performed to examine viability, malondialdehyde (MDA) level, inflammatory cytokine levels, and the level of genes and proteins.

RESULTS

Our findings illustrated that miR-3646 was up-regulated but CYP2J2 was down-regulated in Ang II-induced hVSMCs. Mechanically, miR-3646 negatively targeted to CYP2J2 in Ang II-induced hVSMCs. These findings indicated that miR-3646 regulated inflammatory response of Ang II-induced hVSMCs via targeting CYP2J2. Moreover, functional researches showed that CYP2J2 overexpression alleviated inflammatory response of Ang II-induced hVSMCs via epoxyeicosatrienoic acids/peroxisome proliferator-activated receptor-γ (EETs/PPARγ) axis, and miR-3646 aggravated inflammatory response of Ang II-induced hVSMCs via mediating CYP2J2/EETs axis.

CONCLUSION

MiR-3646 accelerated inflammatory response of Ang II-induced hVSMCs via CYP2J2/EETs axis. Our findings illustrated the specific molecular mechanism of miR-3646 regulating hypertension.

[The application of neural network to output estimation of an impeller artificial heart]

In this paper, several methods of output estimation of artificial heart are introduced briefly, and the authors put forward a method for the application of neural network to the output estimation of an impeller artificial heart. According to the laboratory results, the application of neural network can solve the problem successfully.

[Pulsatile rotary pumps with low hemolysis]

As is well known, a pulsatile flow is important in assisted-circulation but it is difficult to produce a pulsatile flow with rotary pump, because excessive hemolysis will be generated. The authors have found that the turbulent shear is the main factor for red cell damage and therefore the key point of pulsatile rotary pumps is to reduce the turbulence by producing a pulsatile flow. In the authors' pulsatile axial pump, the pulsatile flow is obtained by axial reciprocation of constant rotating impeller; the rotation and reciprocation of the impeller are driven separately by a DC motor and a pneumatic device. Though a physiological pulsatile flow could be achieved and turbulence would not increase remarkably because the impeller rotates constantly, a second driver except a DC motor is nevertheless necessary, thus the system will become complicated. In the authors' pulsatile radial pump, a pulsatile flow is achieved by changing the rotating speed of the impeller periodically. Turbulence is minimized by a special design of twisted vanes which enable the blood flow to change its direction rather than its dimension during periodic change of rotating speed. Hemolysis tests demonstrated that the index of hemolysis(IH) of the author's pulsatile radial pump is 0.020, with is slightly more than that of the author's nonpulsatile radial pump(IH = 0.015). Animal experiments indicated that the pulsatile radial pump can assist the circulation of calves for several months without harm to blood elements and organ functions of the recipients.

[A permanent implantable pulsatile impeller heart with a specially devised needle bearing]

The author's implantable pulsatile impeller pump can assist the circulation of the calves for several months. The termination of the experiments was related to wear of the mechanical bearing, which resulted in vibration of the rotor and pump failure. It seemed as if the experiments could have lasted indefinitely if the bearing had not failed. To solve the problem of bearing wear, a specially devised rolling bearing was investigated and applied to the impeller pump. Its service life is more than 10 years due to the wear-proof roller made of ultra-highmolecular weight polythene. This newly devised impeller heart promises to have long-term and permanent applications. Compared with the magnetic bearing, the rolling bearing has the advantages of simpler construction and control, no consumption of energy, and better reliability.

[Effect of various assist pumps on recovering the ventricular function]

With the authors' diaphragm pump and pulsatile as well as nonpulastile impeller pumps, and the clinically used Sarns Roller, both left ventricular assist and biventricular assist experiments were performed on mini pigs and calves. The results demonstrate that the pulsatile impeller pump is the best assist pump for recovering the heart function, because it maintains the pulsatility of aortic pressure by heart failure and thus increases the circulation volume, and it enlarges the diastolic pressure so as to increase the perfusion in coronary artery because it has no backflow.

Identification of allosteric sites in rabbit phosphofructo-1-kinase

Earlier studies indicated an evolutionary relationship between bacterial and mammalian phosphofructo-1-kinases (PFKs) that suggests duplication, tandem fusion, and divergence of catalytic and effector binding sites of a prokaryotic ancestor to yield in eukaryotes a total of six organic ligand binding sites. The identities of residues involved in the four binding sites for allosteric ligands in mammalian PFK have been inferred from this assumed relationship. In the current study of the C isozyme of rabbit PFK, two arginine residues that can be aligned with important residues in the catalytic and allosteric binding sites of bacterial PFK and that are conserved in all eukaryotic PFKs were mutated. Arg-48 was suggested previously to be part of either the ATP inhibitory or the adenine nucleotide activating site. However, the mutant enzyme showed only slightly less sensitivity to ATP inhibition and was fully activatable by adenine nucleotides. On the other hand, sensitivity to citrate and 3-phosphoglycerate inhibition was lost, indicating an important role for Arg-48 in the binding of these allosteric effectors. Mutation of Arg-481, homologous to an active site residue in bacterial PFK, prevented binding and allosteric activation by fructose 2,6-bisphosphate. A new relationship between the allosteric sites of mammalian PFK and bacterial PFK is proposed.

[The animal experiments and clinical trial of impeller pump used as left ventricular or biventricular assist device]

The authors' impeller pump as a left ventricular or biventricular assist device was evaluated in animal experiments and clinical trial. Three calves survived over 6 weeks in left ventricular assist experiments and neither blood damage nor organ dysfunction of the animals was detected. In clinical trial, the pump supported both the greater and lesser circulation of a 6-year-old child with trilogy of Fallot and low output syndrome after open heart surgery. In 43 hours the pump worked properly. The pump weighing 240 g can perform either in pulsatile or in nonpulsatile mode. In pulsatile pumping, the impeller changes its rotating speed periodically by introducing a square wave form voltage into the motor coil.

[The application of a Salmonella typhimurium biotyping method to the epidemiological surveys and surveillance]

In order to explore a new and effective means to the investigation and surveillance on Salmonella typhimurium infection, the authors applied a biotyping method of S. typhimurium invented by Duguid to the surveillance of nosocomial infection and tracing of infected case as well as cause of food-poisoning. Results showed that the major biotypes of strains isolated from children of acquired nosocomial infection with biotypes of strains from hospital environment and medical staff were quite similar. The biotype of cultures from the urine in a paralytic patient was the same as from the environment of the household and the wife's hands. The biotypes of strains identified from food-poison cases and leftovers was the same as isolated from ducks. It is believed that nosocomicial infection among children was caused by contamination of bacteria in hospital environment and carriers of medical staff. The urinary infection of a paralytic patient was due to environment pollution of the household, but not to nosocomial infection. The food-poisoning case was caused by the consumption of ducks infected with the bacteria.

[Analysis of retinoic acid effects on craniofacial development in quail embryo]

Craniofacial deformities caused by retinoic acid (RA) treatment are well known, but its mechanisms remain to be elucidated. In order to study RA-induced deformities during craniofacial morphogenesis, several different stages and regions of quail embryo in ovo were examined. It was found that the RA injection to the subgerminal space in early-stage (H.H. stage 8) affects specifically craniofacial morphogenesis. Superficially, the acrania and the exencephalia are the most remarkable deformities. Bone and cartilage staining has revealed the hypoplasia of maxilla in high frequencies. Histochemical analyses have demonstrated abnormal development and growth of the central nervous system (CNS). The expression of the Nau gene, a marker of post-mitotic neuroblasts, was also examined by in situ hybridization. Strong expression of the Nau gene in normal embryo was observed in the mantle zone in CNS in the E5 embryo. In contrast, Nau negative nervous tissues were often observed in the RA-treated E5 quail embryo, which indicates abnormal proliferation and differentiation of the neuroblasts in the CNS.