Cellular specificity related to monoglyceride-induced cell death

Combination of cell metabolomics and pharmacology: A novel strategy to investigate the neuroprotective effect of Zhi-zi-chi decoction

ETHNOPHARMACOLOGICAL RELEVANCE

Zhi-zi-chi Decoction(ZZCD), a traditional Chinese medicine formula, has been reported its potential protective effect on psychological sub-health diseases. However, there still remains a lack of molecular mechanism interpretation.

AIM OF THE STUDY

This study was aimed at investigating the mechanism of glutamate-induced toxicity in PC12 cells and the neuroprotective effect of ZZCD based on a novel strategy of the combination of cell metabolomics and pharmacology.

MATERIALS AND METHODS

The PC12 cells were treated with glutamate to simulate neurotoxic cell model. Gas chromatography coupled with mass spectrometry based on cell metabolomics approach was performed to comprehensively investigate the molecular mechanism of glutamate-induced toxicity The cell viability and cytotoxicity analysis, the determination of glutathione reductase(GR), superoxide dismutase(SOD) and reactive oxygen species(ROS), apoptosis analysis and western blot analysis were performed to evaluate the neuroprotection of ZZCD.

RESULTS

Forty metabolites were identified as potential biomarkers in model cells by principal components analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA). Glutamate decreased the GR and SOD activities, increased the level of intracellular ROS, activated the apoptotic pathway, and induced the changes of energy metabolism, amino acid metabolism and lipid metabolism. In addition, the extract of ZZCD could reverse the disturbed metabolic pathways by regulating those potential biomarkers and exerted anti-oxidation and anti-apoptosis.

CONCLUSION

ZZCD has neuroprotective effect and the novel strategy can be applicable for other traditional Chinese medicine formulas.

Glycerides isolated from the aerial parts of Malva verticillata cause immunomodulation effects via splenocyte function and NK anti-tumor activity

A preliminary study revealed that a 10 µg/mL n-BuOH fraction of Malva verticillata aerial parts significantly enhanced splenocyte proliferation and induced significant enhancement of natural-killer (NK) cell activity against tumor cells (YAC-1). This study was initiated to identify the principal components that exhibited these activities, and four glycerides were isolated through repeated SiO2 and ODS column chromatography. Structures of compounds 1-4 were determined to be (2S)-1-O-palmitoyl glyceride, (2S)-1-O-stearoyl glyceride, (2S)-1-O-linolenoyl glyceride, and (2S)-1,2-di-O-linoleoyl glyceride, respectively. Compounds 1-3 showed potential immune-enhancing activity in murine splenocyte and natural-killer (NK) cells at 10 µM. In contrast, compound 4 showed weak activity, indicating the monoacyl glycerides (1-3) are more effective than diacyl glyceride (4). Also, the longer the carbon number of the fatty acid in monoacyl glyceride, the better the activity, and the monoacyl glyceride including an unsaturated fatty acid (3) is more effective than the glycerides including the saturated fatty acids (1-2).

Low dose aerosol infection of mice with virulent type A Francisella tularensis induces severe thymus atrophy and CD4+CD8+ thymocyte depletion

Francisella tularensis is a gram-negative facultative intracellular bacterium and the causative agent of tularemia. Two subspecies (type A and B strains) of the pathogen exist, the former being much more virulent than the latter for humans and other higher mammals. In this study, we examined the effect of virulent strains of F. tularensis infection on the thymus and thymocytes and the potential mechanisms involved. Low-dose aerosol exposure of C57BL/6 mice with type A, but not type B, F. tularensis caused severe reduction in thymus weight and destruction of thymocytes, particularly CD4+CD8+ thymocytes, by day 4 after infection. The depletion of thymocytes was accompanied by a significant increase in circulating cortisone levels and could be partially prevented by adrenalectomy. Moreover, thymus atrophy and thymocyte depletion following infection were abolished in mice deficient in tumor necrosis factor receptors 1 and 2, but not in FasL-deficient mice. The severe destruction of the thymus and selective depletion of immature thymocytes during type A F. tularensis infection may represent a key pathogenic mechanism in tularemia and could hinder the development of an effective primary immune response against this highly virulent pathogen.

Toxicity of a mixture of fatty acids on human blood lymphocytes and leukaemia cell lines

The effect of a mixture of fatty acids upon lymphocyte and leukaemia cell death was examined. Peripheral lymphocytes from healthy subjects and two human leukaemia cell lines-Jurkat (T lymphocyte) and Raji (B lymphocyte) cells-were treated with increasing concentrations (0.1-0.4 mM) of a fatty acid mixture in a proportion mimicking that of the free fatty acids in plasma. Features of cell death were then evaluated. Phosphatidylserine externalization, and DNA fragmentation (apoptosis), and loss of cell membrane integrity (necrosis) and mitochondrial depolarization (common feature of cell death) were observed in leukaemia cells after the fatty acid treatment for up to 48 h. Human lymphocytes, however, when submitted to the same treatment presented apoptotic feature only. These findings indicate that a free fatty acid mixture (mimicking the proportion found in plasma) triggers apoptosis of leukaemia cell lines followed by loss of cell membrane integrity, whereas in human circulating lymphocytes the same treatment causes apoptosis only. Evidence is presented herein that mitochondria from leukaemic cells are more susceptible to the toxicity of the fatty acids than mitochondria from human circulating lymphocytes.

Monoglycerides induce apoptosis in human leukemic cells while sparing normal peripheral blood mononuclear cells

A major drawback of the current antineoplastic treatments is their lack of specificity toward cancer cells, because they are most often cytotoxic to normal cells, thus creating related side effects. Hence, the identification of new apoptosis-inducing agents, specifically targeting malignant cells while sparing their normal counterparts, is of crucial interest. We show here that monoglycerides, a family of lipids consisting of a single fatty acid attached to a glycerol backbone, induce cell death in several human leukemic cell lines. Importantly, treatment of primary leukemic cells, obtained from B-cell chronic lymphocytic leukemia patients, resulted in rapid apoptosis. In striking contrast, resting or activated human peripheral blood mononuclear cells from healthy individuals were resistant to the same treatment. Therefore, these compounds could represent potential antileukemic drugs or could allow for the design of novel therapeutic agents applied to leukemia.