β-escin activates ALDH and prevents cigarette smoke-induced cell death

BACKGROUND

The tobacco use is one of the biggest public health threats worldwide. Cigarette smoke contains over 7000 chemicals among other aldehydes, regarded as priority toxicants. β-escin (a mixture of triterpenoid saponins extracted from the Aesculus hippocastanum. L) is a potent activator of aldehyde dehydrogenase (ALDH) - an enzyme catalyzing oxidation of aldehydes to non-toxic carboxylic acids.

PURPOSE

The aim of this study was to evaluate the effect of β-escin on ALDH activity, ALDH isoforms mRNA expression and cytotoxicity in nasal epithelial cells exposed to cigarette smoke extract (CSE).

METHODS

Nasal epithelial cells from healthy non-smokers were treated with β-escin (1 µM) and exposed to 5% CSE. After 6- or 24-hours of stimulation cell viability, DNA damage, ALDH activity and mRNA expression of ALDH isoforms were examined.

RESULTS

24 h β-escin stimulation revised CSE induced cytotoxicity and DNA damage. Cells cultured with β-escin or exposed to CSE responded with strong increase in ALDH activity. This effect was more pronounced in cultures treated with combination of β-escin and CSE. The strongest stimulatory effect on ALDH isoform mRNA expression was observed in cells cultured simultaneously with β-escin and CSE: at 6 h for ALDH1A1 and ALDH3A1, and at 24 h for ALDH1A3, ALDH3A2, ALDH3B1, and ALDH18A1. Combined β-escin and CSE treatment prevented the CSE-induced inhibition of ALDH2 expression at 24 h.

CONCLUSIONS

β-escin is an effective ALDH stimulatory and cytoprotective agent and might be useful in the prevention or supportive treatment of tobacco smoke-related diseases.

Optimization of human myoblasts culture under different media conditions for application in the in vitro studies

Human primary in vitro cell cultures are among the most challenging procedures in cellular biology laboratory practice. Myoblasts-progenitor of skeletal muscle origin represent a promising therapeutic cell source since the procedure of their isolation is not technically demanding, and the in vitro culture is relatively straightforward. Myoblasts could be considered as the candidates for clinical applications due to their regenerative potential, and as the carriers of therapeutic proteins introduced through genetic modifications. The main goal of this prospective study was to evaluate different myoblasts isolation strategies based on the pre-plating technique and cells density characteristics. Moreover, testing of different myoblast media formulations-both commercially available and in-house made was performed. Our goal was to establish the in vitro protocol of myoblasts culture allowing for preservation of the proliferative potential and desired phenotype. Our results revealed that in culture of myoblasts of human muscle origin, the pre-plate technique and cell density differences did not correlate with changes in the proliferative potential, however it was observed that low density cells maintained expression of the CD56 marker up to the higher passages. Assessment of different types of culture media confirmed the best performance for DMEM based media without Chicken Embryo Extract (CEE) addition. Cells cultured in DMEM+FBS medium revealed high expression of CD56 and CD90 antigens, absence of the hematopoietic markers and presented stable proliferation profile. This finding is in line with guidelines of regulatory agencies recommending removal of the xeno-derived reagents from the manufacturing process of Advanced Therapy Medicinal Products (ATMP). In this study, human myoblasts culture was optimized in vitro under different media conditions. The next approach in assessment of myoblasts propagation for potential clinical applications will be testing of the clinical grade human platelet lysate (hPL) instead of the FBS.

Beneficial effects of β-escin on muscle regeneration in rat model of skeletal muscle injury

BACKGROUND

Recent advancements in understanding β-escin action provide basis for new therapeutic claims for the drug. β-escin-evoked attenuation of NF-κB-dependent signaling, increase in MMP-14 and decrease in COUP-TFII content and a rise in cholesterol biosynthesis could be beneficial in alleviating muscle-damaging processes.

PURPOSE

The aim of this study was to investigate the effect of β-escin on skeletal muscle regeneration.

METHODS

Rat model of cardiotoxin-induced injury of fast-twich extensor digitorum longus (EDL) and slow-twich soleus (SOL) muscles and C2C12 myoblast cells were used in the study. We evaluated muscles obtained on day 3 and 14 post-injury by histological analyses of muscle fibers, connective tissue, and mononuclear infiltrate, by immunolocalization of macrophages and by qPCR to quantify the expression of muscle regeneration-related genes. Mechanism of drug action was investigated in vitro by assessing cell viability, NF-κB activation, MMP-2 and MMP-9 secretion, and ALDH activity.

RESULTS

In rat model, β-escin rescues regenerating muscles from atrophy. The drug reduces inflammatory infiltration, increases the number of muscle fibers and decreases fibrosis. β-escin reduces macrophage infiltration into injured muscles and promotes their M2 polarization. It also alters transcription of muscle regeneration-related genes: Myf5, Myh2, Myh3, Myh8, Myod1, Pax3 and Pax7, and Pcna. In C2C12 myoblasts in vitro, β-escin inhibits TNF-α-induced activation of NF-κB, reduces secretion of MMP-9 and increases ALDH activity.

CONCLUSIONS

The data reveal beneficial role of β-escin in muscle regeneration, particularly in poorly regenerating slow-twitch muscles. The findings provide rationale for further studies on β-escin repositioning into conditions associated with muscle damage such as strenuous exercise, drug-induced myotoxicity or age-related disuse atrophy.

Relationship between left ventricular global longitudinal strain, infarct size and left ventricular function in patients with acute myocardial infarction in a stem cell therapy study

Introduction

It is critically important to determine the accuracy, and relationships between, non-invasive imaging modalities, such as two-dimensional echocardiography (TTE), gated single-photon emission computed tomography (SPECT) and cardiac magnetic resonance imaging (cMRI) in patients with recent acute myocardial infarction (AMI) because these are used as clinical trial endpoints. Modest improvements in the left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV) and infarct zone size (IS) have been reported in AMI stem cells therapy trials (SCT).

Purpose

The aim of the study was to evaluate left-ventricular global longitudinal strain (GLS) in patients with AMI enrolled to SCT and assess its relation with infarct zone, LVEF and LVEDV using multimodality imaging including TTE, cMRI and SPECT.

Methods

Twenty-eight patients (21 male, 7 female, mean age 60.0±8.7 years) with first AMI, 2–5 days after left anterior descending percutaneous coronary intervention (PCI) and IS ≥10% were enrolled. GLS was evaluated with two-dimensional speckle tracking echocardiography (aCMQ, Philips Epiq 7). Infarct zone was measured using SPECT (E.CAM, Siemens) and gadolinium-enhanced cMRI (Siemens Magnetom Sonata 1.5T). LVEF and LVEDV were assessed with TTE (Auto-ROI, Philips), SPECT (GSQUAN, Siemens) and cMRI (MASS Medis). Measurements were obtained independently by blinded analysts.

Results

Mean GLS was −11.0±2.5% and showed a positive correlation with infarct zone by SPECT and MRI, negative with TTE-LVEF and cMRI-LVEF (Figure 1) and borderline with SPECT-LVEF (r=−0.35, p=0.08). There was no correlation between GLS and TTE-LVEDV (r=−0.25, p=0.25); SPECT-LVEDV (r=−0.38, p=0.077) and MRI-LVEDV (r=−0.20, p=0.365).

Patients in the third and fourth GLS quartile had a smaller IS measured by MRI and a trend toward a smaller infarct zone by SPECT (table 1). Patients in the GLS fourth quartile had higher TTE-LVEF and a trend toward higher cMRI-LVEF compared with other quartiles.

LVEF measured with TTE and cMRI was higher compared with SPECT-LVEF (+2.6±6.8%, p=0.006 and +4.2±7.8%, p=0.030, respectively) with no difference between TTE-LVEF and MRI-LVEF (p=0.823) (Table 1).

LVEDV evaluated by SPECT and MRI was higher compared with TTE-LVEDV (+48.3±24.9 ml, +47.7±29.5 ml, both p<0.001) with no difference between SPECT-LVEDV and MRI-LVEDV (p=0.984)

Conclusions

In patients with anterior wall AMI, 2–5 days after PCI, GLS showed a good correlation with infarct zone quantified by SPECT and MRI and with LVEF measured with TTE and cMRI. GLS might thus be a valuable tool in the evaluation of myocardial injury in SCT.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): STRATEGMED 265761 “CIRCULATE” National Centre for Research and Development/Poland/ZDS/00564 Jagiellonian University Medical College Table 1Figure 1

Evolution of left ventricular function after Wharton's jelly mesenchymal stem cells transcoronary administration: 5-year follow up in a pilot cohort of CIRCULATE-AMI Randomized Trial

Introduction

CIRCULATE-Acute Myocardial Infarction is a double-blind controlled trial randomizing (RCT) in 105 consecutive patients with their first, large AMI (cMRI-LVEF ≤45% and/or cMRI-infarct size ≥10% of LV) with successful infarct-related artery (IRA) primary percutaneous coronary intervention (pPCI) to transcoronary administration of Wharton's Jelly Mesenchymal Stem Cells (WJMSCs) vs. placebo (2:1). The pilot study cohort (PSC) preceded the RCT.

Aim

To evaluate WJMSCs long-term safety, and evolution of left-ventricular (LV) function in CIRCULATE-AMI PSC.

Material and methods

30 000 000 WJMSCs (50% labelled with 99mTc-exametazime) were administered via IRA in a ten-patient PCS (age 32–65 years, peak hs-Troponin T 17.3±9.1ng/mL and peak CK-MB 533±89U/L, cMRI-LVEF 40.3±2.7% and infarct size 20.1±2.8%) at ≈5–7 days after AMI using a cell delivery-dedicated, coronary-non-occlusive method. Other treatments were per guidelines.

WJMSCs showed an unprecedented high myocardial uptake (30.2±5.3%; 95% CI 26.9–33.5%), corresponding to ≈9×10 000 000 cells retention in the infarct zone – in absence of epicardial flow or myocardial perfusion impairment (TIMI-3 in all; cTFC 45±8 vs. 44±9, p=0.51) or any hs-Troponin T elevation. Five-year follow up included cardiac Magnetic Resonance Imaging (cMRI) (at baseline, 1 year and 3 years) and detailed echocardiography (echo) at baseline, 1 year, 3 years and 5 years.

Results

By 5 years, one patient died from a new, non-index territory AMI. There were no other cardiovascular events and MACCE that might be related to WJMSCs transplantation.

On echo (Fig), there was an increase in left ventricular ejection fraction (LVEF) between WJMSCs administration point and 1 year (37.7±2.9% vs. 48.3±2.5%, p=0.002) that was sustained at 3 years (47.2±2.6%, p=0.005 vs. baseline) and at 5 years: (44.7±3.2%, p=0.039 vs. baseline). LVEF reached a peak at 1 year after the AMI and WJMSCs transfer (Fig). cMRI data (obtained up to 3 years; 1 year 41.9±2.6% vs. 51.0±3.3%, p<0.01; 3 years 52.2±4.0%, p<0.01 vs. baseline) were consistent with the echo LVEF assessment.

Conclusions

5-year follow up in CIRCULATE-AMI PSC indicates that WJMSC transcoronary application is safe and may be associated with an LVEF improvement. The magnitude of LV increase appears to peak at 1 year, suggesting a potential role for repeated WJMSCs administration(s). Currently running double-blind RCT will provide placebo-controlled insights into the WJMSCs effect(s) on changes in LV function, remodelling, scar reduction and clinical outcomes.

Echo-LVEF evolution

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): STRATEGMED 265761 “CIRCULATE” National Centre for Research and Development/Poland/ZDS/00564 Jagiellonian University Medical College

Long-term outcomes of the micronet-covered stent system routine use for carotid revsacularization in stroke prevention: PARADIGM-Extend 5 year evidence

Background

Diffusion-weighted magnetic resonance imaging indicates that micronet-covered embolic prevention stent system effectively minimizes peri-procedural and prevents lesion-related post-procedural cerebral embolism in carotid artery stenting but long-term clinical evidence is missing.

Purpose

To provide long-term clinical and duplex ultrasound evaluation of safety and efficacy of the system use in consecutive carotid revascularization patients.

Methods

PARADIGM-EXTEND is in all-comer, all-referrals-tracked study with no exclusion criteria other than lack of NeuroVascular Team-determined indication. Clinically asymptomatic patients receive revascularization only in case of increased-stroke-risk characteristics. Adverse events are independently adjudicated.

Results

Currently 451 patients (48–87 years, 59% symptomatic, 127 women) with 490 arteries crossed the first follow-up window of 30 days. There has been 100% micronet-covered embolic prevention stent system use (ie, no other stent type/s used throughout study). Proximal/distal intra-procedural neuroprotection use was 38.3%/61.7%. Large balloon/high-pressure stent optimization was routine, leading to a single-digit (mean 6.9%) residual diameter stenosis. Independent neurologist and duplex evaluation are before and after revascularization (48h and 30 days, then yearly).

Peri-procedural death or major ischemic stroke rate was 0%. One event (prior infarct scar asymptomatic extension in prolonged hypotension course) was adjudicated as minor stroke (0.22%), and there was 1 periprocedural MI (type 2, in 2-vessel non-revascularizable CTO; 0.22%).

By 30 days there were no further ischaemic strokes (0%) but there was 1 haemorrhagic transformation that led to death (0.22%) and 1 bleeding-related death (0.22%). Thus total 30-day death/stroke was 0.66%, and total death/stroke/MI was 0.88%.

By 60 months there were 3 contralateral, 1 ipsilateral (device-unrelated), and 2 posterior circulation strokes. Baseline internal carotid artery velocities were 3.72±1.25 and 0.63±0.69 m/s (peak-systolic and end-diastolic). Post-procedural in-stent velocities were normal and remained normal throughout the 60-month follow-up period: 0.78±040 and 0.21±0.10 (1y); 0.75±0.36 0.19±0.09 (2y); 0.75±0,35 and 0.21±0.09 (3y); 0.72±0.27 and 0.20±0.07 (4y); 0.79±0.58 and 0.21±0.11m/s (5y).

There were 2 in-stent restenoses by 1y (including 1 that occurred with de novo neck radiotherapy) and 1 other by 2y (total 2y in-stent restenosis of 1.1%) but no further ones (0% in-stent restenosis at 2–5y).

Conclusions

PARADIGM-Extend long-term clinical and duplex ultrasound evidence is consistent with normal healing and sustained safety and stroke prevention efficacy of the micronet-covered embolic prevention stent system used routinely, on top of optimized medical therapy, for stroke prevention in symptomatic and increased-stroke-risk asymptomatic subjects with carotid stenosis recommended for revasularization by the NeuroVascular Team.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Jagiellonian University Medical College

Isolation and culture of human primary keratinocytes-a methods review

Keratinocyte culture is a necessary and widely used tool in a variety of experimental dermatological and biomedical studies. Literature search has revealed a variety of different protocols of human primary keratinocyte isolation and culture. Therefore, the aim of this paper was to review and summarize current trends in human primary keratinocyte culture techniques. We present data on the most popular and effective methods of human keratinocyte isolation and cultivation obtained from screening of 945 papers published during the last 10 years.

Stem cells migration during skeletal muscle regeneration - the role of Sdf-1/Cxcr4 and Sdf-1/Cxcr7 axis

The skeletal muscle regeneration occurs due to the presence of tissue specific stem cells - satellite cells. These cells, localized between sarcolemma and basal lamina, are bound to muscle fibers and remain quiescent until their activation upon muscle injury. Due to pathological conditions, such as extensive injury or dystrophy, skeletal muscle regeneration is diminished. Among the therapies aiming to ameliorate skeletal muscle diseases are transplantations of the stem cells. In our previous studies we showed that Sdf-1 (stromal derived factor −1) increased migration of stem cells and their fusion with myoblasts in vitro. Importantly, we identified that Sdf-1 caused an increase in the expression of tetraspanin CD9 - adhesion protein involved in myoblasts fusion. In the current study we aimed to uncover the details of molecular mechanism of Sdf-1 action. We focused at the Sdf-1 receptors - Cxcr4 and Cxcr7, as well as signaling pathways induced by these molecules in primary myoblasts, as well as various stem cells - mesenchymal stem cells and embryonic stem cells, i.e. the cells of different migration and myogenic potential. We showed that Sdf-1 altered actin organization via FAK (focal adhesion kinase), Cdc42 (cell division control protein 42), and Rac-1 (Ras-Related C3 Botulinum Toxin Substrate 1). Moreover, we showed that Sdf-1 modified the transcription profile of genes encoding factors engaged in cells adhesion and migration. As the result, cells such as primary myoblasts or embryonic stem cells, became characterized by more effective migration when transplanted into regenerating muscle.

Polyphenolic compounds from Abutilon grandiflorum leaves

The flavonol glycosides: kaempferol 3-O-beta-(6"-p-coumaroyl)-glucopyranoside, kaempferol and quercetin 3-O-beta-glucopyranosides and 3-O-beta-rutinosides were isolated and identified from the leaves of Abutilon grandiflorum. Their structures were established by chemical and spectroscopic methods. The presence of phenolic acids: p-hydroxybenzoic, p-coumaric, syringic, and vanillic was confirmed by TLC.

Bioactive Flavone Sulfates of Abutilon indicum Leaves

Two flavones, hypolaetin 8- O-β-glucuronopyranoside 3″- O-sulfate and isoscutellarein 8- O-β-glucuronopyranoside 3″-O-sulfate, together with hypolaetin 8- O-β-glucuronopyranoside, kaempferol 3- O-α-rhamnopyranosyl (1“→6′”)-β-glucopyranoside and quercetin 3- O-α-rhamnopyranosyl (1″→6″”)-β-glucopyranoside were isolated from the leaves of Abutilon indicum, and their structures elucidated by acid hydrolysis and spectroscopic methods, including HPLC/ESI-MS, and 1H, 13C NMR, COSY, HMQC, HSQC and HMBC spectroscopic experiments. The antimicrobial activity of hypolaetin 8- O-β-glucuronopyranoside 3″- O-sulfate and of isoscutellarein 8- O-β-glucuronopyranoside 3″- O-sulfate against Staphylococcus aureus was confirmed.

Oxidative stress regulated expression of Ubiquitin Carboxyl-terminal Hydrolase-L1: Role in cell survival

The ubiquitin Carboxyl-terminal Hydrolase-L1 gene (UCHL1) is a key enzyme in the protein degradation pathway; however, its precise role in protecting cells under stress conditions is unclear. In the present study we investigated the activity of this gene in human NT2/D1 embryonal carcinoma cells subjected to oxygen-glucose deprivation (OGD) and reoxygenation. OGD/reoxygenation cause global metabolic changes due to energy withdrawal and the subsequent generation of reactive oxygen species which initiates either a stress-adaptation-survival response or cell death, depending on the severity of the insult. A bi-phasic change in UCHL1 expression was observed by Q-PCR, Western blotting and flow cytometry. Down regulation of UCHL1 was detected immediately after OGD treatment and its expression was subsequently restored and increased 6 h after OGD treatment as well as during reoxygenation. Furthermore, flow cytometry analysis detected a lower level of UCHL1 only in apoptotic cells that had severe loss of mitochondrial membrane potential. Accordingly, down-regulation of endogenous UCHL1 by antisense cDNA in mouse N2a neuroblastoma cells increased the cell's sensitivity to OGD treatment. This down-regulation of endogenous UCHL1 led to the accumulation of p27, suggesting that UCHL1 is an essential gene to maintain cell homeostasis under normal growth and oxidative stress conditions.

S/MAR-binding properties of Sox2 and its involvement in apoptosis of human NT2 neural precursors

DNA fragmentation in apoptosis, especially in lymphocytic cells, is initiated at scaffold/matrix attachment regions (S/MARs) and is preceded by the degradation of nuclear proteins. The present study was performed to establish whether the same mechanism occurred in human NT2 cells subjected to oxygen and glucose deprivation (OGD). We analyzed the integrity of c-myc S/MAR containing a base-unpairing region (BUR)-like element, which we established to be a binding site of the transcription factor Sox2. An accumulation of DNA breaks in close proximity to this element and a degradation of Sox2 were observed early in the OGD-induced apoptotic response. Identification of Sox2 as a novel c-myc BUR-binding protein was achieved through yeast one-hybrid screening and the Sox2/DNA interaction was confirmed by electrophoretic mobility shift assay and immunoprecipitation with Sox2 antibody. Our data support the notion that early proteolysis of unique BUR-binding proteins might represent a universal mechanism that renders these DNA sites vulnerable to endonucleolysis.

Role of mitochondria in neuronal cell death induced by oxidative stress; neuroprotection by Coenzyme Q10

Neuronal cells depend on mitochondrial oxidative phosphorylation for most of their energy needs and therefore are at a particular risk for oxidative stress. Mitochondria play an important role in energy production and oxidative stress-induced apoptosis. In the present study, we have demonstrated that external oxidative stress induces mitochondrial dysfunction leading to increased ROS generation and ultimately apoptotic cell death in neuronal cells. Furthermore, we have investigated the role of Coenzyme Q10 as a neuroprotective agent. Coenzyme Q10 is a component of the mitochondrial respiratory chain and a potent anti-oxidant. Our results indicate that total cellular ROS generation was inhibited by Coenzyme Q10. Further, pre-treatment with Coenzyme Q10 maintained mitochondrial membrane potential during oxidative stress and reduced the amount of mitochondrial ROS generation. Our study suggests that water-soluble Coenzyme Q10 acts by stabilizing the mitochondrial membrane when neuronal cells are subjected to oxidative stress. Therefore, Coenzyme Q10 has the potential to be used as a therapeutic intervention for neurodegenerative diseases.

Flavonoids from Abutilon theophrasti flowers

Nine flavonoid compounds: kaempferol 3-0-beta-(6"-p-coumaroyl)-glucopyranoside, myricetin 3-O-beta-glucopyranoside, quercetin 3-0-beta-glucopyranoside, quercetin 3-0-alpha-rhamnopyranosyl (1-->6)-beta-glucopyranoside, kaempferol 3-0-beta-glucopyranoside, kaempferol 3-0-alpha-rhamnopyranosyl (1-->6)-beta-glucopyranoside, quercetin 7-0-beta-glucoside, quercetin 7-0-beta-diglucoside, kaempferol 7-0-beta-diglucoside were isolated and identified from the flowers of Abutilon theophrasti.

Paraquat induces oxidative stress and neuronal cell death; neuroprotection by water-soluble Coenzyme Q10

Neuronal cell death induced by oxidative stress is correlated with numerous neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and stroke. The causes of sporadic forms of age-related neurodegenerative diseases are still unknown. Recently, a correlation between paraquat exposure and neurodegenerative diseases has been observed. Paraquat, a nonselective herbicide, was once widely used in North America and is still routinely used in Taiwan. We have used differentiated Human Neuroblastoma (SHSY-5Y) cells as an in vitro model to study the mechanism of cell death induced by paraquat. We observed that paraquat-induced oxidative stress in differentiated SHSY-5Y cells as indicated by an increase in the production of cellular reactive oxygen species (ROS). Furthermore, apoptosis was evident as indicated by cellular and nuclear morphology and DNA fragmentation. Interestingly, pretreatment of SHSY-5Y cells with water-soluble Coenzyme Q10 (CoQ10) before paraquat exposure inhibited ROS generation. Pretreatment with CoQ10 also significantly reduced the number of apoptotic cells and DNA fragmentation. We also analyzed the effect of paraquat and CoQ10 on isolated mitochondria. Our results indicated that treatment with paraquat induced the generation of ROS from isolated mitochondria and depolarization of the inner mitochondrial membrane. Pretreatment with CoQ10 was able to inhibit ROS generation from isolated mitochondria as well as the collapse of mitochondrial membrane potential. Our results indicate that water-soluble CoQ10 can prevent oxidative stress and neuronal damage induced by paraquat and therefore, can be used for the prevention and therapy of neurodegenerative diseases caused by environmental toxins.

Regulation of DNaseY activity by actinin-α4 during apoptosis

DNaseY, a Ca(2+)- and Mg(2+)-dependent endonuclease, has been implicated in apoptotic DNA degradation; however, the molecular mechanisms controlling its involvement in this process have not been fully elucidated. We have obtained evidence from yeast two-hybrid screening and coimmunoprecipitation experiments that DNaseY interacted physically with actinin-alpha4 and this interaction significantly enhanced its endonuclease activity. Accordingly, simultaneous overexpression of both proteins in PC12 cells dramatically increased the rate of apoptosis in response to teniposide' VM26. However, overexpression of DNaseY alone neither triggered apoptosis nor facilitated cell death in response to VM26 or serum deprivation. Instead, the overexpression of DNaseY increased the production of single-strand DNA breaks and evoked a profound upregulation of DNA repair pathways. Taken together, our results point to a novel regulatory mechanism of DNaseY activity and offer an explanation for why cells must first cleave key DNA repair and replication proteins before the successful execution of apoptosis.

Flavonoids from flowers of Malva crispa L. (Malvaceae)

The following flavonoids were isolated and identified from the flowers of Malva crispa L.: kaempferol 3-O-beta-glucopyranoside, 3-O-(6"-tran-p-coumaroyl)-beta-D-glucopyranoside, 7-O-beta-D-glucopyranoside, 3-O-alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranoside and 3,7-O-diglucoside as well as quercetin 3-O-beta-D-glucopyranoside, 3-O-alpha-L-rhamnopyranosyl (1-->6) -beta-D-glucopyranoside and apigenin 7-O-beta-D-glucopyranoside. Their structures were established by chemical analysis, UV, 1H and 13C NMR spectrometry.

Flavonoids in the leaves of Asclepias incarnata L

Seven flavonoid compounds: quercelin 3-O-beta-galactopyranoside, 3-O-beta-glucopyranoside, 3-O-arabinoside, 3-O-beta-glucopyranosyl (1-->2)-beta-galactopyranoside, 3-O-beta-xylopyranosyl (1-->2)-beta-galactopyranoside, 3-O-alpha-rhamnopyranosyl (1-->2)-beta-galactopyranoside and kaempferol 3-beta-glucopyranoside were isolated and identified from the leaves of Asclepias incarnata, L. (Asclepiadaceae).

Electrospray mass spectrometric decomposition of some glucuronic acid-containing flavonoid diglycosides

Mass spectrometric fragmentation patterns of herbacetin 3-O-glucopyranoside-8-O-glucuronopyranoside (1), gossypetin 3-O-glucopyranoside-8-O-glucuronopyranoside (2) and takakin 7-O-glucopyranoside-8-O-glucuronopyranoside (3) were elucidated from mass spectra obtained with electrospray ionisation. The usefulness of the fragmentation patterns observed in the positive and negative mode for structural elucidation of the studied compounds is discussed. The fragmentation of 3 was substantially different from 1 and 2, especially in the negative mode. In order to explain these differences, theoretical calculations were performed.

Mapping the initial DNA breaks in apoptotic Jurkat cells using ligation-mediated PCR

Apoptotic DNA degradation could be initiated by the accumulation of single-strand (ss) breaks in vulnerable chromatin regions, such as base unpairing regions (BURs), which might be preferentially targeted for degradation by both proteases and nucleases. We tested this hypothesis in anti-Fas-treated apoptotic Jurkat cells. Several nuclear proteins known for their association with both MARs and the nuclear matrix, that is, PARP, NuMA, lamin B and SATB1, were degraded, but the morphological rearrangement of the BUR-binding SATB1 protein was one of the earliest detected changes. Subsequently, we have identified several genes containing sequences homologous to the 25 bp BUR element of the IgH gene, a known SATB1-binding site, and examined the integrity of genomic DNA in their vicinity. Multiple ss breaks were found in close proximity to these sites relative to adjacent regions of DNA. Consistent with our prediction, the results indicated that the initiation of DNA cleavage in anti-Fas-treated Jurkat cells occurred within the BUR sites, which likely became accessible to endonucleases due to the degradation of BUR-binding proteins.

Flavonoid compounds in the flowers of Abutilon indicum (L.) Sweet (Malvaceae)

Seven flavonoid compounds: luteolin, chrysoeriol, luteolin 7-O-beta-glucopyranoside, chrysoeriol 7-O-beta-glucopyranoside, apigenin 7-O-beta-glucopyranoside, quercetin 3-O-beta-glucopyranoside, quercetin 3-O-alpha-rhamnopyranosyl (1 --> 6)-beta-glucopyranoside, were isolated and identified from the flowers of Abutilon indicum (L.) Sweet (Malvaceae).

Differentiation of interglycosidic linkages in permethylated flavonoid glycosides from linked-scan mass spectra (B/E)

A series of per-O-methylated flavonoid di- and tri-glycosides, linked with 1-2 and/or 1-6 glycosidic bonds between sugar rings that were isolated from different plant materials were analyzed. It was demonstrated that the fragmentation behavior of permethylated flavonoid glycosides is dependent on the glycosidic bond placement between sugars. Y(n) type fragment ions, created after glycosidic bond cleavage with oxygen retention on sugar at the reducing end for permethylated compounds, were observed in the normal and linked-scan mass spectra recorded for alpha(1-2) bonded conjugates of flavonoid di- and tri-glycosides. Moreover, for alpha (1-6) linked glycosides, Y fragments created after rearrangement and elimination of internal sugar residues were observed in addition to Y(n) type ions, but these fragment ions were not registered in normal desorption ionization spectra. This second type of fragmentation was also reported previously in collision-induced dissociation tandem mass spectrometry (CID MS/MS) spectra of some oligosaccharides and flavonoid glycosides, but their presence was independent of the glycosidic bonds placement between sugar rings.

SATB1 cleavage by caspase 6 disrupts PDZ domain-mediated dimerization, causing detachment from chromatin early in T-cell apoptosis

SATB1 is expressed primarily in thymocytes and orchestrates temporal and spatial expression of a large number of genes in the T-cell lineage. SATB1 binds to the bases of chromatin loop domains in vivo, recognizing a special DNA context with strong base-unpairing propensity. The majority of thymocytes are eliminated by apoptosis due to selection processes in the thymus. We investigated the fate of SATB1 during thymocyte and T-cell apoptosis. Here we show that SATB1 is specifically cleaved by a caspase 6-like protease at amino acid position 254 to produce a 65-kDa major fragment containing both a base-unpairing region (BUR)-binding domain and a homeodomain. We found that this cleavage separates the DNA-binding domains from amino acids 90 to 204, a region which we show to be a dimerization domain. The resulting SATB1 monomer loses its BUR-binding activity, despite containing both its DNA-binding domains, and rapidly dissociates from chromatin in vivo. We found this dimerization region to have sequence similarity to PDZ domains, which have been previously shown to be involved in signaling by conferring protein-protein interactions. SATB1 cleavage during Jurkat T-cell apoptosis induced by an anti-Fas antibody occurs concomitantly with the high-molecular-weight fragmentation of chromatin of ~50-kb fragments. Our results suggest that mechanisms of nuclear degradation early in apoptotic T cells involve efficient removal of SATB1 by disrupting its dimerization and cleavage of genomic DNA into loop domains to ensure rapid and efficient disassembly of higher-order chromatin structure.

Kaempferol, isorhamnetin and their glycosides in the flowers of Asclepias syriaca L

The following flavonoid compounds have been isolated and identified from the flowers of Asclepias svriaca L.: kaempferol, kaempferol 7-O-beta-glucoside, kaempferol 3-O-beta-galactopyranoside, kaempferol 3-O-beta-xylopyranosyl (1-->2)-beta-galactopyranoside, kaempferol 3-O-beta-glucopyranosyl (1-->2)-beta-galactopyranoside, isorhamnetin, isorhamnetin 7-O-beta-glucoside, isorhamnetin 3-O-beta-galactoside and isorhamnetin 3-O-beta-xylopyranosyl (1-->2)-beta-galactopyranoside. Their structures were established by conventional (acid, enzymatic hydrolysis and H2O2 oxidation) and spectral analysis (UV, 1H NMR, 13C NMR).

Kaempferol and its glycosides in the seeds hair of Asclepias syriaca L

The following flavonoid compounds have been isolated and identified from the seeds hair of Asclepias syriaca L.: kaempferol, kaempferol 3-O-beta-galactopyranoside, kaempferol 3-O-beta-xylopyranosyl (1 --> 2)-beta-galactopyranoside, kaempferol 3-O-beta-glucopyranosyl (1 --> 2)-beta-galactopyranoside, kaempferol 3-O-alpha-rhamnopyranosyl (1 --> 2)-beta-galactopyranoside. Their structures were established by acid hydrolysis, H2O2 oxidation and spectral analysis (UV, 1H, 3C NMR, MS).

Quercetin and its glycosides in the flowers of Asclepias syriaca L

The following flavonoid compounds have been isolated and identified from the flowers of Asclepiac syriaca L.: quercetin and its glycosides: 7-O-galactoside, 7-O-glucoside, 3-O-beta-D-xylopyranoside(1-->2) beta-D-galactoside and 3-O-beta-D-glucopyranoside(1-->2) beta-D-galactoside. Their structures were established by acid and enzymatic hydrolysis or H2O2 oxidation as well as spectral analysis (UV, 1H and 13C NMR).

Protein synthesis, DNA degradation, and morphological changes during programmed cell death in labial glands of Manduca sexta

Labial glands of the tobacco hornworm Manduca sexta (Lepidoptera: Sphingiidae, homologues of Drosophila salivary glands, undergo programmed cell death (PCD) in a 4-day period during larva-to-pupa metamorphosis. The programmed death of the labial gland was examined by electron microscopy and measurement of protein synthesis as well as measurement of DNA synthesis, end-labeling of single strand breaks, and pulsed-field gel electrophoresis. One of the earliest changes observed is a sharp drop in synthesis of most proteins, coupled with synthesis of a glycine-rich protein, reminiscent of silk-like proteins. From a morphological standpoint, during the earliest phases the most prominent changes are the formation of small autophagic vacuoles containing ribosomes and an apparent focal dissolution of the membranes of the endoplasmic reticulum, whereas later changes include differing destruction at the lumenal and basal surfaces of the cell and erosion of the basement membrane. By the fourth day of metamorphosis, individual cells become rapidly vacuolated in a cell-independent manner. In the vacuolated cells on day 3, chromatin begins to coalesce. It is at this period that unequivocal nucleosomal ladders are seen and end-labeling in situ or electrophoretic techniques document single on double-strand breaks, respectively. DNA synthesis ceases shortly after the molt to the fifth instar, as detected by incorporation of tritiated thymidine and weak TUNEL labeling. Large size fragments of DNA are seen shortly after DNA synthesis ceases and thence throughout the instor, raising the possibility of potential limitations built into the cells before their final collapse.

Caspase-dependent and independent cell death in rat hepatoma 5123tc cells

The objective of this study was to establish whether apoptosis in 5123tc rat hepatoma cells required the caspase-3 dependent pathway. Apoptosis was induced by either growth factor deprivation or treatment with a topoisomerase II inhibitor, VM26, in the absence or presence of caspase inhibitors (DEVD-fmk, z-VAD-fmk and BAF). The results indicated that, although these inhibitors at 10 microM concentration completely blocked caspase-3 activity, they had no effect on either the rate of cell death or on any other apoptotic features, e.g., chromatin condensation, DNA fragmentation, protein cleavage, suggesting that caspase-3 was not required to mediate nuclear destruction in these hepatoma cells. At higher concentrations, up to 100 microM, z-VAD-fmk and BAF, but not DEVD-fmk, did block apoptosis, however, they also caused cell swelling and membrane permeabilization, which are the hallmarks of necrotic cell death. Clearly, high concentrations of these inhibitors must have interfered non-specifically with other metabolic pathways, e.g., z-VAD-fmk at a high concentration blocked protein phosphorylation, and caused cell death by a different mechanism.

Effects of neoplastic transformation and teniposide (VM26) on protein kinase C isoform expression in rodent fibroblasts

This study examined changes in protein kinase C (PKC) isoforms in rodent fibroblasts (rat F111 and mouse NIH3T3), transformed by the polyoma virus middle T antigen (mT) and undergoing apoptosis in response to teniposide (VM26). The mT-transformed cells up-regulated PKC delta and down-regulated both PKC epsilon and PKC lambda expression, and were more sensitive to the drug than their non-transformed counterparts. The drug treatment further lowered the expression of PKC epsilon, triggered nuclear translocation of PKC delta and its site-specific proteolysis, consistent with the notion that changes in specific PKC isoforms play a role not only in the neoplastic transformation of fibroblasts, but also in their apoptotic response.

Neither caspase-3 nor DNA fragmentation factor is required for high molecular weight DNA degradation in apoptosis

In this paper, we show that there is a two-step process of DNA fragmentation in apoptosis; DNA is first cleaved to large fragments of 50-300 kb that are subsequently cleaved to smaller oligonucleosomes in some, but not all cells. Significantly, only the first stage is considered essential for cell death since some cells, for example human MCF7 breast carcinoma cells and human NT2 neuronal cells, do not show this behavior but still display normal nuclear morphological apoptotic changes. In cells that usually produce small fragments blocking the second (internucleosomal) stage of DNA fragmentation prevents neither nuclear condensation nor apoptosis. We are beginning to understand why the extent of DNA fragmentation during apoptosis varies enormously and why it appears to be a function of the cell type not the inducer. Presumably, this reflects the content of not only endonuclease activit(ies) but also on the ability of the cells to activate caspases, particularly caspase-3, and other proteases that may be involved in endonuclease activation. Since NT2 cells activate caspase-3, but do not correctly process DFF45, other factors must also impinge on the inevitability of that process.

Apoptosis-related functional features of the DNaseI-like family of nucleases

Rat DNaseYb and its human homolog DHP2 are members of a new family of DNaseI-like endonucleases. They contain all the conserved amino acid residues to engage a DNaseI-like catalytic activity and the same molecular mechanisms of DNA hydrolysis. The sequence similarity can be extended to other families of nucleases, such as FEN-1, DNA polymerases, RNaseH and exonuclease III, involved in the ion-dependent hydrolysis of nucleic acids. Their unique features include the NLS signals that place them in the nuclei and a high content of positively charged amino acid residues that results in their high affinity for the substrate. Their properties are consistent with a role in the early stage DNA degradation during apoptosis. The caspase-DFF45/CIDE-CPAN pathway is most likely involved in the second stage of internucleosomal DNA degradation. However, cells express constitutively multiple transcripts encoding DNA degrading enzymes and related molecules, hence they have the molecular diversity to engage the self-destructive pathway appropriate to a given trigger.

Qualitative and quantitative analysis of phenolic acids in Asclepias syriaca L

TLC and HPLC was applied to qualitative and quantitative determination of phenolic acids free and liberated by acid and alkaline hydrolysis in common milkweed. The presence of phenolic acids, namely p-hydroxybenzoic, p-coumaric, protocatechuic and caffeic acids, was confirmed in the leaves and flowers. Moreover, the flowers contained gallic acid, and the leaves contained alpha-resorcylic, vanilic and chlorogenic acids. Conjugated forms of phenolic acids predominate in the plant. They hydrolyse mainly to coffeic, p-coumaric, ferulic and p-hydroxybenzoic acids.

Evidence that DNA fragmentation in apoptosis is initiated and propagated by single-strand breaks

Apoptosis is characterised by the degradation of DNA into a specific pattern of high and low molecular weight fragments seen on agarose gels as a distribution of sizes between 50-300 kb and sometimes, but not always, a ladder of smaller oligonucleosomal fragments. Using a 2D pulsed field-conventional agarose gel electrophoresis technique, where the second dimension is run under either normal or denaturing conditions, we show that single-strand breaks are introduced into DNA at the initial stages of fragmentation. Using single-strand specific nuclease probes we further show that the complete fragmentation pattern, including release of small oligonucleosomal fragments can also be generated by a single-strand endonuclease. Three classes of sites where single-strand breaks accumulate were identified. The initial breaks produce a distribution of fragment sizes (50 kb to >1 Mb) similar to those generated by Topoisomerase II inhibitors suggesting that cleavage may commence at sites of attachment of DNA to the nuclear matrix. A second class of rare sites is also cut further reducing the size distribution of the fragments to 50-300 kb. Thirdly, single-strand breaks accumulate at the linker region between nucleosomes eventually causing double-strand scissions which release oligonucleosomes. These observations further define the properties of the endonuclease responsible for DNA fragmentation in apoptosis.

Detection of DNA fragmentation and endonucleases in apoptosis

DNA degradation during apoptosis is endonuclease mediated and proceeds through an ordered series of stages commencing with the production of large DNA pieces of 300 kb which are then degraded to fragments of 50 kb. The 50-kb fragments are further degraded, in some but not all cells, to smaller pieces (10-40 kb) releasing the small oligonucleosome fragments that are detected as a characteristic DNA ladder on conventional agarose gels. Methodology is presented for the detection of both DNA ladders and the initial stages of DNA fragmentation using pulsed-field gel electrophoresis. We have developed electrophoresis conditions that resolve large fragments of DNA and also retain the smaller fragments on the same gel. Methods for the detection of endonuclease activities responsible for the cleavage of DNA during apoptosis are also presented.