Temporal variations in protein tyrosine kinase activity in leukaemic cells: response to all-trans retinoic acid

Dexamethasone suppresses the proliferation and migration of VSMCs by FAK in high glucose conditions

Background

High glucose conditions cause some changes in the vessels of diabetes through the signal transduction pathways. Dexamethasone and other corticosteroids have a wide range of biological effects in immunological events. In the present study, the effects of dexamethasone were investigated on the VSMC (vascular smooth muscle cell) proliferation, and migration based on the FAK gene and protein changes in high glucose conditions.

Methods and materials

The vascular smooth muscle cells were cultured in DMEM and were treated with dexamethasone (10^–7 M, 10^–6 M, and 10^–5 M) for 24, and 48 h in high glucose conditions. The cell viability was estimated by MTT method. The FAK gene expression levels and pFAK protein values were determined by RT-qPCR and western blotting techniques, respectively. A scratch assay was used to evaluate cellular migration.

Results

The FAK gene expression levels decreased significantly dependent on dexamethasone doses at 24 and 48 h. The pFAK protein values decreased significantly with a time lag at 24- and 48-h periods as compared with gene expression levels.

Conclusion

The results showed that the inhibition of VSMC proliferation and migration by dexamethasone in the high glucose conditions may be related to the changes of FAK.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00604-3.

An appreciation of the prescience of Don Gilbert (1930-2011): master of the theory and experimental unravelling of biochemical and cellular oscillatory dynamics

We review Don Gilbert's pioneering seminal contributions that both detailed the mathematical principles and the experimental demonstration of several of the key dynamic characteristics of life. Long before it became evident to the wider biochemical community, Gilbert proposed that cellular growth and replication necessitate autodynamic occurrence of cycles of oscillations that initiate, coordinate and terminate the processes of growth, during which all components are duplicated and become spatially re-organised in the progeny. Initiation and suppression of replication exhibit switch-like characteristics, that is, bifurcations in the values of parameters that separate static and autodynamic behaviour. His limit cycle solutions present models developed in a series of papers reported between 1974 and 1984, and these showed that most or even all of the major facets of the cell division cycle could be accommodated. That the cell division cycle may be timed by a multiple of shorter period (ultradian) rhythms, gave further credence to the central importance of oscillatory phenomena and homeodynamics as evident on multiple time scales (seconds to hours). Further application of the concepts inherent in limit cycle operation as hypothesised by Gilbert more than 50 years ago are now validated as being applicable to oscillatory transcript, metabolite and enzyme levels, cellular differentiation, senescence, cancerous states and cell death. Now, we reiterate especially for students and young colleagues, that these early achievements were even more exceptional, as his own lifetime's work on modelling was continued with experimental work in parallel with his predictions of the major current enterprises of biological research.

Ethanol elevates physiological all-trans-retinoic acid levels in select loci through altering retinoid metabolism in multiple loci: a potential mechanism of ethanol toxicity

All-trans-retinoic acid (atRA) supports embryonic development, central nervous system function, and the immune response. atRA initiates neurogenesis and dendritic growth in the hippocampus and is required for spatial memory; superphysiological atRA inhibits neurogenesis, causes teratology and/or embryo toxicity, and alters cognitive function and behavior. Because abnormal atRA shares pathological conditions with alcoholism, inhibition of retinol (vitamin A) activation into atRA has been credited widely as a mechanism of ethanol toxicity. Here, we analyze the effects of ethanol on retinoid concentrations in vivo during normal vitamin A nutriture, using sensitive and analytically robust assays. Ethanol either increased or had no effect on atRA, regardless of changes in retinol and retinyl esters. Acute ethanol (3.5 g/kg) increased atRA in adult hippocampus (1.6-fold), liver (2.4-fold), and testis (1.5-fold). Feeding dams a liquid diet with 6.5% ethanol from embryonic day 13 (e13) to e19 increased atRA in fetal hippocampus (up to 20-fold) and cortex (up to 50-fold), depending on blood alcohol content. One-month feeding of the 6.5% ethanol diet increased atRA in adult hippocampus (20-fold), cortex (2-fold), testis (2-fold), and serum (10-fold). Tissue-specific increases in retinoid dehydrogenase mRNAs and activities, extrahepatic retinol concentrations, and atRA catabolism combined to produce site-specific effects. Because a sustained increase in atRA has deleterious effects on the central nervous system and embryo development, these data suggest that superphysiological atRA contributes to ethanol pathological conditions, including cognitive dysfunction and fetal alcohol syndrome.-Kane, M. A., Folias, A. E., Wang, C., Napoli, J. L. Ethanol elevates physiological all-trans-retinoic acid levels in select loci through altering retinoid metabolism in multiple loci: a potential mechanism of ethanol toxicity.

Temporal variation in the expression of the p53 protein in proliferating and differentiating murine erythroleukaemia cells

Temporal changes in the expression of p53 were investigated during hexamethylene bisacetamide (HMBA)-induced differentiation of murine erythroleukaemic (MEL) cells. Cell preparations were analysed by SDS-PAGE and western immunoblotting, which detected an immunospecific band of molecular mass 53 kDa. This analysis provided semi-quantitative information. Cell extracts were analysed further by means of ELISA techniques, using a p53-specific antibody, to provide quantitative data. In time series experiments in which cells were isolated at 15, 30 and 60 min intervals, dynamic variations in the expression of the p53 protein were detected in both the untreated and the HMBA-treated MEL cells. In all cases, the effects were complex with variations in amplitude, frequency and phasing of the rhythms. The available evidence suggests that the observed patterns, like periodic variations in other systems, are modified in rhythmic fashion with respect to period and amplitude. The results add further support for our view that it is essential to consider the dynamics when interpreting the role of p53 and cellular processes in general.

A chemical waveform synthesizer

Algorithms and methods were developed to synthesize complex chemical waveforms in open volumes by using a scanning-probe microfluidic platform. Time-dependent variations and oscillations of one or several chemical species around the scanning probe, such as formation of sine waves, damped oscillations, and generation of more complex patterns, are demonstrated. Furthermore, we show that intricate bursting and chaotic calcium oscillations found in biological microdomains can be reproduced and that a biological cell can be used as a probe to study receptor functionalities as a function of exposure to time-dependent variations of receptor activators and inhibitors. Thus, the method allows for studies of biologically important oscillatory reactions. More generally, the system allows for detailed studies of complex time-varying chemical and physical phenomena in solution or at solution/surface interfaces.