Tao-Hong-Si-Wu Decoction improves depressive symptoms in model rats via restorations of neural transmitters and ameliorations of BDNF-CREB-arginase I axis disorders

Background Depressive disorder (DD) has become a global health problem. Applications of Chinese medicine have been demonstrated to be potential in the treatment of DD. Tao-Hong-Si-Wu decoction (TSD), a traditional Chinese medicine formula is widely used to treat ameliorate anemia, liver and heart dysfunctions, and inflammation. Such symptoms are also associated with DD. Hence, our initial hypothesis was to observe and explore the targets of the effect of TSD on DD. Methods The DD model was established by chronic unpredictable mild stress (CUMS) in rats. The measurements of body weight and behavioral tests were performed to confirm the success of modeling and observe the effect of TSD on the model animals. A gas-chromatography coupled with mass spectrometry (GC-MS)-based metabolomic analysis was conducted to reveal the metabolic characteristics related to the curative effect of TSD. Serum serotonin and arginase I (Arg I), which are associated with the key feature metabolites responsible for the effect of TSD on depression, were assessed by an ELISA assay. Proteins in the Brain-derived neurotrophic factor (BDNF)/ Tropomyosin receptor kinase B (TrkB)/cAMP response element-binding protein (CREB) signaling, which lead to the regulations of Arg I, were analyzed using Western blot assay. Results Body weight losses and increased immobility durations in the behavioral tests were observed in the CUMS rats while such features were attenuated in the TSD-treated rats. General decreases in serum amino acids and energetic metabolites were found in CUMS rats. Significant increased ornithine and urea, the products of arginase degradation, were also characterized in the DD-mimicked rats. These metabolic dysregulations were reversed in the TSD-treated groups. Upregulated Arg I and downregulated serotonin were observed in the model group but the dysregulations were improved in the TSD-treated groups. Compared with the blank control, lower expressions of BDNF, TrkB, extracellular signal-regulated kinases (ERK), p-ERK, and CREB were found in the hippocampus of CUMS rats. Expressions of the proteins were restored in all the TSD-treated groups. Conclusions TSD improves depression-like symptoms in CUMS rats, which may be primarily related to its effect both on enhancing the release of neural transmitters such as glycine and serotonin and on the improvement of disorders of the BNDF-CREB-Arg I axis.

EFFECT OF VIBRATION STRESS BOTH ON THE SHIFTS OF SOLUBLE PROTEIN FRACTIONS FROM RAT LIVER AND ON THE ARGINASE I ACTIVITY

Vibration pathology is in the second place among diseases connected to the profession. The vibration effect both on the protein fraction shifts and on the activities of I type arginase (Arg) IA and IB from white rat liver has been studied in the conditions of 5-, 10- and 15-day vibration state. In the initial state of vibration some decrease of Arg IA and Arg IB activities was revealed as compared to the control without general protein spectrum change of liver extract. Along with vibration effect, the expression level of Arg IA was increased with duration enhancement, which possibly is due to hyperammonemia, in the result of which ureagenesis is stimulated. Stimulation of easy available adaptation reserves were described due to protein catabolism. Analysis of shifts of general and enzyme protein fractions in the conditions of vibration effect allows to reveal their qualitative and quantitative changes and to make important the organism adaptation reactions that result from anabolic and catabolic process relations. It is possible that the revealed changes in the activity of arginase IA and IB are a biologically expedient mechanism for regulating the activity of hepatic arginase during vibration stress.

A synthetic peptide as an allosteric inhibitor of human arginase I and II

Arginine metabolism mediated by arginases plays a critical role in cell and tissue function. The arginine hydrolysis is deeply involved in the urea cycle, which helps the kidney excrete ammonia from blood. Upregulation of arginases affects microenvironment stability due to the presence of excess urea in blood. To regulate the arginase activities properly, a synthetic peptide based on the structure of human arginase I was designed and assessed. Preliminary data shows it inhibits human arginase I and II with an IC50 of 2.4 ± 0.3 and 1.8 ± 0.1 mmol, respectively. Our kinetic analysis indicates the inhibition is not competitive with substrate – suggesting an allosteric mechanism. This result provides a step towards specific inhibitors design.

Human recombinant arginase I [HuArgI (Co)-PEG5000]-induced arginine depletion inhibits ovarian cancer cell adhesion and migration through autophagy-mediated inhibition of RhoA

Ovarian carcinoma is the second most common malignancy of the female reproductive system and the leading cause of death from female reproductive system malignancies. Cancer cells have increased proliferation rate and thus require high amounts of amino acids, including arginine. L-arginine is a non-essential amino acid synthesized from L-citrulline by the Arginosuccinate synthetase (ASS1) enzyme. We have previously shown that the ovarian cancer cells, SKOV3, are auxotrophic to arginine, and that arginine deprivation by treatment with the genetically engineered human arginase I (HuArgI (Co)-PEG5000) triggers the death of SKOV3 cells by autophagy. In this study we examine the effect of HuArgI (Co)-PEG5000 on ovarian cancer cell migration and we dissect the mechanism involved. Wound healing assays, 2D random cell migration assays and cell adhesion analysis indicate that arginine deprivation decreases SKOV3 cell migration and adhesion. This effect was mimicked when autophagy was induced through rapamycin and reversed with the autophagy inhibitor chloroquine when autophagy was inhibited. This proved that arginine deprivation leads to the inhibition of cancer cell migration through autophagy, in addition to cell death. In addition, we were able to establish through pull-down assays and reversal experiments, that arginine deprivation-mediated autophagy inhibits cell migration through a direct inhibition of RhoA, member of the Rho family of GTPases. In conclusion, here we identify, for the first time, an autophagy-mediated inhibition of RhoA that plays an important role in regulating ovarian cancer cells motility and adhesion in response to arginine depletion.