UVB-radiation-induced apoptosis in Jurkat cells: a coordinated fourier transform infrared spectroscopy-flow cytometry study

Safe-Shields: Basal and Anti-UV Protection of Human Keratinocytes by Redox-Active Cerium Oxide Nanoparticles Prevents UVB-Induced Mutagenesis

Cerium oxide nanoparticles (nanoceria), biocompatible multifunctional nanozymes exerting unique biomimetic activities, mimic superoxide-dismutase and catalase through a self-regenerating, energy-free redox cycle driven by Ce3+/4+ valence switch. Additional redox-independent UV-filter properties render nanoceria ideal multitask solar screens, shielding from UV exposure, simultaneously protecting tissues from UV-oxidative damage. Here, we report that nanoceria favour basal proliferation of primary normal keratinocytes, and protects them from UVB-induced DNA damage, mutagenesis, and apoptosis, minimizing cell loss and accelerating recovery with flawless cells. Similar cell-protective effects were found on irradiated noncancerous, but immortalized, p53-null HaCaT keratinocytes, with the notable exception that here, nanoceria do not accelerate basal HaCaT proliferation. Notably, nanoceria protect HaCaT from oxidative stress induced by irradiated titanium dioxide nanoparticles, a major active principle of commercial UV-shielding lotions, thus neutralizing their most critical side effects. The intriguing combination of nanoceria multiple beneficial properties opens the way for smart and safer containment measures of UV-induced skin damage and carcinogenesis.

Molecular Spectroscopic Markers of DNA Damage

Every cell in a living organism is constantly exposed to physical and chemical factors which damage the molecular structure of proteins, lipids, and nucleic acids. Cellular DNA lesions are the most dangerous because the genetic information, critical for the identity and function of each eukaryotic cell, is stored in the DNA. In this review, we describe spectroscopic markers of DNA damage, which can be detected by infrared, Raman, surface-enhanced Raman, and tip-enhanced Raman spectroscopies, using data acquired from DNA solutions and mammalian cells. Various physical and chemical DNA damaging factors are taken into consideration, including ionizing and non-ionizing radiation, chemicals, and chemotherapeutic compounds. All major spectral markers of DNA damage are presented in several tables, to give the reader a possibility of fast identification of the spectral signature related to a particular type of DNA damage.

FTIR spectroscopy of whole cells for the monitoring of yeast apoptosis mediated by p53 over-expression and its suppression by Nigella sativa extracts

p53 over expression in yeast results in cell death with typical markers of apoptosis such as DNA fragmentation and phosphatidylserine externalization. We aimed to substitute/supplement classical fluorescent techniques (TUNEL, Annexin V, ROS detection) usually used to detect biochemical changes occurring during yeast apoptosis mediated by p53 over expression and the effect of anti-apoptotic purified molecules from Nigel (Nigella sativa) extracts on these same yeasts by the label free technique of FTIR spectroscopy. The comparison of the entire IR spectra highlighted clear modifications between apoptotic p53-expressing yeasts and normal ones. More precisely, DNA damage was detected by the decrease of band intensities at 1079 and 1048 cm^-1. While phosphatidylserine exposure was followed by the increase of νsCH₂ and νasCH₂ bands of unsaturated fatty acids that were exhibited at 2855 and 2926 cm^-1, and the appearance of the C = O ester functional group band at 1740 cm^-1. In a second step, this FTIR approach was used to estimate the effect of a purified fraction of the Nigel extract. The modulation of band intensities specific to DNA and membrane status was in agreement with apoptosis supression in presence of the Nigel extracts. FTIR spectroscopy is thus proven to be a very reliable technique to monitor the apoptotic cell death in yeast and to be used as a means of evaluating the biomolecules effect on yeast survival.

The importance of hydration and DNA conformation in interpreting infrared spectra of cells and tissues

Since Watson and Crick's historical papers on the structure and function of DNA based on Rosalind Franklin's and Maurice Wilkin's X-ray diffraction patterns tremendous scientific curiosity has been aroused by the unique and dynamic structure of the molecule of life. A-DNA and B-DNA represent different conformations of the DNA molecule, which is stabilised by hydrogen interactions between base pairs, stacking interactions between neighboring bases and long-range intra- and inter-backbone forces. This review highlights the contribution Fourier transform infrared (FTIR) spectroscopy has made to the understanding of DNA conformation in relation to hydration and its potential role in clinical diagnostics. The review will first begin by elucidating the main forms of DNA conformation found in nature and the general structures of the A, B and Z forms. This is followed by a detailed critique on infrared spectroscopy applied to DNA conformation highlighting pivotal studies on isolated DNA, polynucleotides, nucleoprotein and nucleohistone complexes. A discussion on the potential of diagnosing cancer using FTIR spectroscopy based on the detection of DNA bands in cells and tissues will ensue, highlighting the recent studies investigating the conformation of DNA in hydrated and dehydrated cells. The method of hydration as a way to facilitate DNA conformational band assignment will be discussed and the conformational change to the A-form upon dehydration will be used to explain the reason for the apparent lack of FTIR DNA signals observed in fixed or air-dried cells and tissues. The advantages of investigating B-DNA in the hydrated state, as opposed to A-DNA in the dehydrated state, are exemplified in a series of studies that show: (1) improved quantification of DNA in cells; (2) improved discrimination and reproducibility of FTIR spectra recorded of cells progressing through the cell cycle; (3) insights into the biological significance of A-DNA as evidenced by an interesting study on bacteria, which can survive desiccation and at the same time undergo the B-A-B transition. Finally, the importance of preserving the B-DNA conformation for the diagnosis of cancer is put forward as way to improve the sensitivity of this powerful technique.

Cell death in human articular chondrocyte: a morpho-functional study in micromass model

Chondrocyte death and loss of extracellular matrix are the central features in articular cartilage degeneration during osteoarthritis pathogenesis. Cartilage diseases and, in particular, osteoarthritis are widely correlated to apoptosis but, chondrocytes undergoing apoptosis "in vivo" more often display peculiar features that correspond to a distinct process of programmed cell death termed "chondroptosis". Programmed cell death of primary human chondrocyte has been here investigated in micromasses, a tridimensional culture model, that represents a convenient means for studying chondrocyte biology. Cell death has been induced by different physical or chemical apoptotic agents, such as UVB radiation, hyperthermia and staurosporine delivered at both 1 and 3 weeks maturation. Conventional electron microscopy was used to analyse morphological changes. Occurrence of DNA fragmentation and caspase involvement were also investigated. At Transmission Electron Microscopy, control cells appear rounding or slightly elongated with plurilobated nucleus and diffusely dispersed chromatin. Typically UVB radiation and staurosporine induce chromatin apoptotic features, while hyperthermia triggers the "chondroptotic" phenotype. A weak TUNEL positivity appears in control, correlated to the well known cell death patterns occurring along cartilage differentiation. UVB radiation produces a strong positivity, mostly localized at the micromass periphery. After hyperthermia a higher number of fluorescent nuclei appears, in particular at 3 weeks. Staurosporine evidences a diffuse, but reduced, positivity. Therefore, DNA fragmentation is a common pattern in dying chondrocytes, both in apoptotic and "chondroptotic" cells. Moreover, all triggers induce caspase pathway activation, even if to a different extent, suggesting a fundamental role of apoptotic features, in chondrocyte cell death.

Monitoring UVR induced damage in single cells and isolated nuclei using SR-FTIR microspectroscopy and 3D confocal Raman imaging

Melanocytes exposed to artificial sunlight and analysed with FTIR and Raman spectroscopy show changes in DNA bands and evidence of lipid accumulation.

Ultraviolet B (UVB) irradiation-induced apoptosis in various cell lineages in vitro

Ultraviolet B (UVB) radiation acts as a strong apoptotic trigger in many cell types, in tumor and normal cells. Several studies have demonstrated that UVB-induced cell death occurs through the generation of reactive oxygen species. The consequent oxidative stress includes the impairment of cellular antioxidants, the induction of DNA damage and the occurrence of apoptosis. In this review, we investigated UVB apoptotic action in various cell models by using ultrastructural, molecular and cytofluorimetric techniques. Myeloid leukemia HL-60, T-lymphoblastoid Molt-4 and myelomonocytic U937 human cells, generally affected by apoptotic stimuli, were studied. Human chondrocytes and C2C12 skeletal muscle cells, known to be more resistant to damage, were also considered. All of them, when exposed to UVB radiation, revealed a number of characteristic apoptotic markers. Membrane blebbing, cytoplasm shrinkage and chromatin condensation were detected by means of electron microscopy. DNA cleavage, investigated by using agarose gel electrophoresis and TUNEL reaction, was observed in suspended cells. Differently, in chondrocytes and in skeletal muscle cells, oligonucleosomic DNA fragmentation did not appear, even if a certain TUNEL positivity was detected. These findings demonstrate that UVB radiation appears to be an ideal tool to study the apoptotic behavior.

Ultrasound-mediated structural changes in cells revealed by FTIR spectroscopy: a contribution to the optimization of gene and drug delivery

Ultrasound effects on biological samples are gaining a growing interest concerning in particular, the intracellular delivery of drugs and genes in a safe and in a efficient way. Future progress in this field will require a better understanding of how ultrasound and acoustic cavitation affect the biological system properties. The morphological changes of cells due to ultrasound (US) exposure have been extensively studied, while little attention has been given to the cells structural changes. We have exposed two different cell lines to 1 MHz frequency ultrasound currently used in therapy, Jurkat T-lymphocytes and NIH-3T3 fibroblasts, both employed as models respectively in the apoptosis and in the gene therapy studies. The Fourier Transform Infrared (FTIR) Spectroscopy was used as probe to reveal the structural changes in particular molecular groups belonging to the main biological systems. The genotoxic damage of cells exposed to ultrasound was ascertained by the Cytokinesis-Block Micronucleus (CBMN) assay. The FTIR spectroscopy results, combined with multivariate statistical analysis, regarding all cellular components (lipids, proteins, nucleic acids) of the two cell lines, show that Jurkat cells are more sensitive to therapeutic ultrasound in the lipid and protein regions, whereas the NIH-3T3 cells are more sensitive in the nucleic acids region; a meaningful genotoxic effect is present in both cell lines only for long sonication times while in the Jurkat cells also a significant cytotoxic effect is revealed for long times of exposure to ultrasound.

Antioxidant micronutrients improve intrinsic and UV-induced apoptosis of human lymphocytes particularly in elderly people

OBJECTIVE

Aging and oxidative stress may lead to enhanced cellular damage and programmed cell death. To study the association of intrinsic apoptosis with age and the effect of antioxidant supplementation on intrinsic and UV-induced apoptosis in children, young and elderly people.

METHODS

The study was a 2 months, double-blind, randomized trial. Three age groups were studied: children, young adults and elderly people. A total of 274 healthy subjects were allocated to a group supplemented with moderate amounts of retinol, β-carotene, α-tocopherol, ascorbic acid and selenium or placebo. Plasma oxidative stress parameters were detected and apoptosis of lymphocytes was evaluated with TUNEL staining.

RESULTS

At baseline, percentages of intrinsic apoptosis were 13.8% and 11.1% in elderly and young people, respectively, both significantly higher than children (6.3%). A decrease of 1.7% and 2.3% in intrinsic apoptosis of lymphocytes was found in the supplemented groups of young and elderly people compared with their control groups (all p values <0.001), but no significant decrease in children. Moreover, percentages UV-induced apoptosis significantly decreased by 1.4%, 1.9% and 3.1% in children, young and elderly people, respectively, compared with control groups after the trial. There were considerable increments in concentrations of plasma β-carotene, retinol, tocopherol, ascorbic acid and selenium in all three treated groups after the supplementation.

CONCLUSIONS

Young and elderly people have a higher intrinsic apoptosis than children, which was improved by antioxidant supplementation. UV-induced damage was attenuated by the supplementation in all three age groups.

A crystal lapiferin derived from Ferula vesceritensis induces apoptosis pathway in MCF-7 breast cancer cells

Ferula vesceritensis is a plant that is used in the traditional medicine in Algeria. Chromatographic investigation of the methylene chloride/methanol extract of the aerial parts of F. vesceritensis afforded a crystal carotene sesquiterpene designed lapiferin (10alpha-acetoxy-6alpha-angeloyloxy-8alpha,9alpha-epoxy-trans-caxotan-4beta-ol) for the first time from this species. The structure was determined by comprehensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC and HRMS, and X-ray data of lapiferin. We report here for the first time the isolation of lapiferin from F. vesceritensis as a new natural source, and we additionally report the first X-ray data for lapiferin. We also report for the first time the specific anti-cancer activity of lapiferin against human breast cancer cells (MCF-7), which is due to apoptosis and not necrosis. Moreover, we have identified for the first time the cell death pathway induced by lapiferin in human breast cancer cells, and also that lapiferin evokes multiple consequences that trigger apoptotic cell death, involving the enhancement of DNA fragmentation, the activation of caspases and the induction of histone acetylation in MCF-7 cells. In conclusion, we record here F. vesceritensis as a new natural source of lapiferin and its first X-ray analysis, and the promising specific anti-cancer activity against human breast cancer of lapiferin and accordingly F. vesceritensis extract.