SRC kinase family inhibitor PP2 promotes DMSO-induced cardiac differentiation of P19 cells and inhibits proliferation.

BACKGROUND: It has been reported recently that PP2, a Src family kinase inhibitor, promotes selective cardiogenesis in embryonic stem cells. However, there is no other research proved pro-cardiogenic characteristic of PP2 so far. In this study, we explored the potential cardiogenic effect of PP2 on P19 cells differentiation. METHODS: P19-αMHC-EGFP cell line was established by transfecting P19 cells with αMHC-EGFP vector in order to evaluate cardiogenesis with EGFP. P19-αMHC-EGFP cells and P19 cells were induced to differentiate into cardiomyocytes with 1%DMSO, 5 µmol/L PP2, or both 1%DMSO and 5 µmol/L PP2. Differentiated cells from P19-αMHC-EGFP cells were then assessed under confocal microscope. Western-blot and RT-PCR were also performed to detect expression of cardiac troponin I and cardiac transcription factors respectively. In addition, the effects of PP2 on proliferation of P19 cells were further examined using Cell Counting Kit-8. RESULTS: EGFP positive cells were firstly detected on day 7 and PP2 alone cannot induce efficient cardiac differentiation of P19-αMHC-EGFP cells. However PP2 supplementation dramatically increases DMSO induced cardiac differentiation than DMSO alone. It was also found that PP2 inhibit proliferation of P19 cells in both a dose-dependent manner and a time-dependent manner. CONCLUSION: PP2 alone cannot substitute DMSO to induce cardiac differentiation, however, PP2 supplementation drastically promotes DMSO-induced cardiac differentiation of P19 cells. The increased percentages of differentiated cardiac myocytes is partly resulting from cell proliferative inhibit effect of PP2 in undifferentiated P19 cells. P19-αMHC-EGFP cell line has the potential to be used for regenerative therapies in experimental models of heart repair.

[Effect of the costimulatory molecules OX40-OX40 ligand interaction on the expression of NFATc1 in leukocytes of apolipoprotein E-deficient mice].

OBJECTIVE: To investigate the effect of OX40/OX40L interaction on the nuclear factor of activated T cells c1 (NFATc1) in ApoE-/- mice. METHODS: Lymphocytes were prepared from mouse spleens after Collar-treated Surgery, then incubated with a range of agonistic anti-OX40 mAbs and inhibitory anti-OX40L mAb to stimulate or inhibit OX40-OX40L interaction in vitro. The expression of NFATc1 mRNA and protein in lymphocytes of ApoE-/- mice was measured by Real Time PCR and flow cytometry, respectively. RESULTS: (1) After stimulating OX40-OX40L signal pathway, the expression of NFATc1 mRNA and protein in leukocytes of ApoE-/- mice was significantly increased, with maximal effect occurring at 20 µg/ml anti-OX40 mAb-stimulated, and peaked at 24 h at any concentration (P < 0.01). (2) Anti-OX40L mAb significantly suppressed the expression of NFATc1 in leukocytes of ApoE-/- mice, with maximal effect occurring at 20 µg/ml anti-OX40L mAb, and peaked at 24 h (P < 0.001). CONCLUSIONS: OX40-OX40L interaction can regulate the mRNA and protein expressions of NFATc1 in lymphocytes of ApoE-/- mice.

A new method for assessing variability of 24 h blood pressure and its first application in 1526 elderly men.

1. Blood pressure variability (BPV) includes physiological and random variations in blood pressure (BP). Commonly used approaches, such as standard deviation (SD) and weighted standard deviation (wSD) methods, do not efficiently assess random variation in BP. In the present study, we propose a novel method to assess individual BP variations, extracting random variation in BP by eliminating physiological variation mathematically. This novel assessment method furthers our understanding of the relationship between BP variation and lacunar infarction (LACI). 2. In the present study, we analysed ambulatory blood pressure monitoring recordings taken from 1526 men aged 60-98 years of age. Individual curves were created using a mathematical method and the related BP variation calculated, namely the SD for individual BP variations. In addition, correlations between LACI and BP variations as determined by the classical SD method, wSD and our novel assessment method (SD') were evaluated. 3. The results demonstrated that 24 h variations in systolic BP (SBP) were closely associated with LACI when the SD and wSD methods were used (P < 0.05), but the most significant correlations were observed when the SD' method was used (P < 0.01). Furthermore, using SD' yielded the lowest value of the parameter P among the three different methods used to analyse BPV. Using the SD' method, a significant correlation was found between variations in SBP and the incidence of LACI (P < 0.05). It was found that the incidence of LACI increased by 2% with each 1 mmHg increase in SBP variation. 4. In conclusion, our novel assessment method enables mathematical removal of interference from physiological BP variation and the results show a better correlation with LACI. Thus, our novel method may be considered a simple index of 24 h BP variation that is superior to conventional SD and wSD methods.

Relationship between CD40 ligand expression and B type natriuretic peptide levels in patients with chronic heart failure.

BACKGROUND: Inflammation plays a pathogenic role in the development of chronic heart failure (CHF). Increasing evidence shows that CD40-CD40 ligand (CD40L) interaction plays a pathogenic role in inflammatory disorders. We assessed whether CD40 ligand expression was abnormal in patients with CHF. METHODS: Twenty normal controls and 86 patients with CHF were investigated. The expression of CD40L on platelets was analyzed by indirect-immunofluorescence flow cytometry, and the soluble CD40L (sCD40L) level was determined by a commercially available enzyme-linked immunosorbent assay (ELISA). B type natriuretic peptide (BNP) was measured by radioimmunoassay. RESULTS: All patients with CHF showed a significant increased expression of CD40L (32.3+/-13.9 MFI) on platelets and sCD40L levels (20.5+/-8.6 microg/l) compared with controls(p<0.0001). CD40L expression on platelets and sCD40L levels positively correlated with New York Heart Association (NYHA) functional class, left ventricular ejection fraction and BNP levels in CHF. CONCLUSIONS: Patients with CHF showed increased expression of CD40L system, which may create a pathogenic role in the development and progression of CHF.