Vascular dopamine-I receptors and atherosclerosis

Therapeutic effects of different polar fractions of hawthorn extract on blood stasis model rats revealed by liquid chromatography-mass spectrometry metabolomics

Hawthorn, a commonly used traditional Chinese medicine, has been suggested to have therapeutic effects on cardiovascular disease. However, effective fractions of hawthorn extract in the treatment of cardiovascular disease, together with possible therapeutic mechanisms, remain unclear. This study aimed to investigate the effects of four different polar fractions of hawthorn extract on blood stasis model rats, and explore the possible metabolic mechanisms by using a liquid chromatography-mass spectrometry metabolomics approach. Evaluation of hemorheology and fibrinogen showed that n-butanol and ethyl acetate fractions of hawthorn extract had significant therapeutic effects on blood stasis model rats. Furthermore, metabolomics analysis showed that n-butanol and ethyl acetate fractions of hawthorn extract could reverse imbalanced biomarkers in plasma and urine of blood stasis model rats. Additionally, metabolic pathway analysis revealed that plasma biomarkers were responsible for several important pathways, including d-glutamine and d-glutamate metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, alanine, aspartate, and glutamate metabolism, sphingolipid metabolism, and arginine biosynthesis. Meanwhile, urine biomarkers were responsible for some important pathways, including phenylalanine metabolism, tyrosine metabolism, and lysine degradation. This study demonstrated that n-butanol and ethyl acetate fractions of hawthorn extract had significant therapeutic effects on blood stasis model rats, and the underlying mechanisms involved multiple metabolic pathways.

Segregated Nanocompartments Containing Therapeutic Enzymes and Imaging Compounds within DNA-Zipped Polymersome Clusters for Advanced Nanotheranostic Platform

Nanotheranostics is an emerging field that brings together nanoscale-engineered materials with biological systems providing a combination of therapeutic and diagnostic strategies. However, current theranostic nanoplatforms have serious limitations, mainly due to a mismatch between the physical properties of the selected nanomaterials and their functionalization ease, loading ability, or overall compatibility with bioactive molecules. Herein, a nanotheranostic system is proposed based on nanocompartment clusters composed of two different polymersomes linked together by DNA. Careful design and procedure optimization result in clusters segregating the therapeutic enzyme human Dopa decarboxylase (DDC) and fluorescent probes for the detection unit in distinct but colocalized nanocompartments. The diagnostic compartment provides a twofold function: trackability via dye loading as the imaging component and the ability to attach the cluster construct to the surface of cells. The therapeutic compartment, loaded with active DDC, triggers the cellular expression of a secreted reporter enzyme via production of dopamine and activation of dopaminergic receptors implicated in atherosclerosis. This two-compartment nanotheranostic platform is expected to provide the basis of a new treatment strategy for atherosclerosis, to expand versatility and diversify the types of utilizable active molecules, and thus by extension expand the breadth of attainable applications.

Gut microbiota and inflammation in chronic kidney disease and their roles in the development of cardiovascular disease

The health and proper functioning of the cardiovascular and renal systems largely depend on crosstalk in the gut-kidney-heart/vessel triangle. Recent evidence suggests that the gut microbiota has an integral function in this crosstalk. Mounting evidence indicates that the development of chronic kidney and cardiovascular diseases follows chronic inflammatory processes that are affected by the gut microbiota via various immune, metabolic, endocrine, and neurologic pathways. Additionally, deterioration of the function of the cardiovascular and renal systems has been reported to disrupt the original gut microbiota composition, further contributing to the advancement of chronic cardiovascular and renal diseases. Considering the interaction between the gut microbiota and the renal and cardiovascular systems, we can infer that interventions for the gut microbiota through diet and possibly some medications can prevent/stop the vicious cycle between the gut microbiota and the cardiovascular/renal systems, leading to a decrease in chronic cardiovascular and renal diseases.

The effect and mechanism of dopamine D1 receptors on the proliferation of osteosarcoma cells

The physiological and pathological roles of dopamine D1 receptors (DR1) in the regulation of functions in tissues and organs have been recognized. However, whether DR1 are expressed in the osteosarcoma cells and inhibit the proliferation of these cells is unknown. In the present study, we found that DR1 were expressed in the osteosarcoma cells (OS732 cells). SKF-38393 (DR1 agonist) and the overexpression of DR1 decreased the proliferation of OS732 cells; SCH-23390 (DR1 antagonist) and the knockdown of DR1 increased the proliferation of OS732 cells, and both SCH-23390 and the knockdown of DR1 abolished the effect of SKF-38393 on the proliferation of OS732 cells. In addition, SKF-38393 down-regulated the phosphorylation of ERK1/2, PI3K, and Akt; SCH-23390 up-regulated the phosphorylation of ERK1/2, PI3K, and Akt, and SCH-23390 cancelled the effect of SKF-38393. The effect of SKF-38393 on the phosphorylation of ERK1/2, PI3K, and Akt and the proliferation of OS732 cells was similar to PD98059 (an ERK inhibitor) or LY294002 (a PI3K inhibitor), respectively. In conclusion, our results suggest that DR1 are expressed in the osteosarcoma cells and inhibit the proliferation of osteosarcoma cells by the down-regulation of the ERK1/2 and PI3K-Akt pathways. These findings provide a novel target for the treatment of the osteosarcoma.

Mechanical stress-initiated signal transduction in vascular smooth muscle cells in vitro and in vivo

Increasing evidence has been demonstrated that hypertension-initiated abnormal biomechanical stress is strongly associated with cardio-/cerebrovascular diseases e.g. atherosclerosis, stroke, and heart failure, which is main cause of morbidity and mortality. How the cells in the cardiovascular system sense and transduce the extracellular physical stimuli into intracellular biochemical signals is a crucial issue for understanding the mechanisms of the disease development. Recently, collecting data derived from our and other laboratories showed that many kinds of molecules in the cells such as receptors, ion channels, caveolin, G proteins, cell cytoskeleton, kinases and transcriptional factors could serve as mechanoceptors directly or indirectly in response to mechanical stimulation implying that the activation of mechanoceptors represents a non-specific manner. The sensed signals can be further sorted and/or modulated by processing of the molecules both on the cell surface and by the network of intracellular signaling pathways resulting in a sophisticated and dynamic set of cues that enable cardiovascular cell responses. The present review will summarise the data on mechanotransduction in vascular smooth muscle cells and formulate a new hypothesis, i.e. a non-specific activation of mechanoceptors followed by a variety of signal cascade activation. The hypothesis could provide us some clues for exploring new therapeutic targets for the disturbed mechanical stress-initiated diseases such as hypertension and atherosclerosis.

D1 dopamine receptor regulation of cell cycle in FGF- and EGF-supported primary cultures of embryonic cerebral cortical precursor cells

In the mammalian fetus, proliferation of the majority of cells destined for the cerebral cortex takes place within the transient proliferative zones of the cerebral wall. Recent investigations have demonstrated that cell of these zones express high levels of D1 dopamine receptors (D1Rs). However, the specific roles of these receptors have not been investigated. The present study tests the hypothesis that D1Rs are capable of regulating the cell cycle of cerebral cortical precursor cells. For this purpose, primary cultures of cells of the proliferative zones from the cerebral wall of 14-day-old mouse fetuses were generated and maintained in the presence of either fibroblast growth factor-2 (FGF2) or epidermal growth factor (EGF). These growth factors were chosen as supporting two distinct populations of precursor cells in the fetal cortical proliferative matrix. The involvement of D1Rs in the regulation of proliferative activity was examined by the addition of a range of concentrations of the D1R-specific agonist, SKF82958, to the culture media. Bromodeoxyuridine incorporation assays demonstrated that exposure to this agonist led to a dose-dependent reduction of DNA synthesis in both FGF2- and EGF-supported cultures. Flow cytometric cell cycle assays further revealed that this was due to prevention of the transition of cells from the G1 phase to the S phase of the cell cycle. The D1R specificity of the effects of SKF82958 was supported in that they were blocked by the addition of the D1R antagonists, SCH23390 or NNC010756. We also found that D1R stimulation induced stronger suppression of proliferative activity in EGF-supported than in FGF2-supported cultures. Our observations suggest that D1Rs are capable of regulating the cell cycle during corticogenesis. Furthermore, they raise a possibility that these receptors may display different efficacies in affecting proliferative activity in FGF2-supported versus EGF-supported cerebral cortical precursor cells.