The trap of the carnivorous plant Venus flytrap (Dionaea muscipula) catches prey by very rapid closure of its modified leaves. After the rapid closure secures the prey, repeated mechanical stimulation of trigger hairs by struggling prey and the generation of action potentials (APs) result in secretion of digestive fluid. Once the prey's movement stops, the secretion is maintained by chemical stimuli released from digested prey. We investigated the effect of mechanical and chemical stimulation (NH4Cl, KH2PO4, further N(Cl) and P(K) stimulation) on enzyme activities in digestive fluid. Activities of β-D-glucosidases and N-acetyl-β-D-glucosaminidases were not detected. Acid phosphatase activity was higher in N(Cl) stimulated traps while proteolytic activity was higher in both chemically induced traps in comparison to mechanical stimulation. This is in accordance with higher abundance of recently described enzyme cysteine endopeptidase dionain in digestive fluid of chemically induced traps. Mechanical stimulation induced high levels of cis-12-oxophytodienoic acid (cis-OPDA) but jasmonic acid (JA) and its isoleucine conjugate (JA-Ile) accumulated to higher level after chemical stimulation. The concentration of indole-3-acetic acid (IAA), salicylic acid (SA) and abscisic acid (ABA) did not change significantly. The external application of JA bypassed the mechanical and chemical stimulation and induced a high abundance of dionain and proteolytic activity in digestive fluid. These results document the role of jasmonates in regulation of proteolytic activity in response to different stimuli from captured prey. The double trigger mechanism in protein digestion is proposed.
- MeSH
- Mechanotransduction, Cellular MeSH
- Cyclopentanes metabolism MeSH
- Cysteine Endopeptidases metabolism MeSH
- Droseraceae enzymology physiology MeSH
- Plant Leaves enzymology physiology MeSH
- Oxylipins metabolism MeSH
- Plant Growth Regulators metabolism MeSH
- Plant Proteins metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
INTRODUCTION: The formation of diabetic ulcers (DU) is a common complication for diabetic patients resulting in serious chronic wounds. There is therefore, an urgent need for complex treatment of this problem. This study examines a bioactive wound dressing of a biodegradable electrospun nanofibrous blend of poly(L-lactide-co-ε-caprolactone) and poly(ε-caprolactone) (PLCL/PCL) covered by a thin fibrin layer for sustained delivery of bioactive molecules. METHODS: Electrospun PLCL/PCL nanofibers were coated with fibrin-based coating prepared by a controlled technique and enriched with human platelet lysate (hPL), fibroblast growth factor 2 (FGF), and vascular endothelial growth factor (VEGF). The coating was characterized by scanning electron microscopy and fluorescent microscopy. Protein content and its release rate and the effect on human saphenous vein endothelial cells (HSVEC) were evaluated. RESULTS: The highest protein amount is achieved by the coating of PLCL/PCL with a fibrin mesh containing 20% v/v hPL (NF20). The fibrin coating serves as an excellent scaffold to accumulate bioactive molecules from hPL such as PDGF-BB, fibronectin (Fn), and α-2 antiplasmin. The NF20 coating shows both fast and a sustained release of the attached bioactive molecules (Fn, VEGF, FGF). The dressing significantly increases the viability of human saphenous vein endothelial cells (HSVECs) cultivated on a collagen-based wound model. The exogenous addition of FGF and VEGF during the coating procedure further increases the HSVECs viability. In addition, the presence of α-2 antiplasmin significantly stabilizes the fibrin mesh and prevents its cleavage by plasmin. DISCUSSION: The NF20 coating supplemented with FGF and VEGF provides a promising wound dressing for the complex treatment of DU. The incorporation of various bioactive molecules from hPL and growth factors has great potential to support the healing processes by providing appropriate stimuli in the chronic wound.
- MeSH
- alpha-2-Antiplasmin MeSH
- Endothelial Cells MeSH
- Wound Healing MeSH
- Humans MeSH
- Nanofibers * MeSH
- Bandages MeSH
- Polyesters pharmacology MeSH
- Vascular Endothelial Growth Factor A * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Cardiac hypertrophy is the result of responses to various physiological or pathological stimuli. Recently, we showed that polycystin-1 participates in cardiomyocyte hypertrophy elicited by pressure overload and mechanical stress. Interestingly, polycystin-1 knockdown does not affect phenylephrine-induced cardiomyocyte hypertrophy, suggesting that the effects of polycystin-1 are stimulus-dependent. In this study, we aimed to identify the role of polycystin-1 in insulin-like growth factor-1 (IGF-1) signaling in cardiomyocytes. Polycystin-1 knockdown completely blunted IGF-1-induced cardiomyocyte hypertrophy. We then investigated the molecular mechanism underlying this result. We found that polycystin-1 silencing impaired the activation of the IGF-1 receptor, Akt, and ERK1/2 elicited by IGF-1. Remarkably, IGF-1-induced IGF-1 receptor, Akt, and ERK1/2 phosphorylations were restored when protein tyrosine phosphatase 1B was inhibited, suggesting that polycystin-1 knockdown deregulates this phosphatase in cardiomyocytes. Moreover, protein tyrosine phosphatase 1B inhibition also restored IGF-1-dependent cardiomyocyte hypertrophy in polycystin-1-deficient cells. Our findings provide the first evidence that polycystin-1 regulates IGF-1-induced cardiomyocyte hypertrophy through a mechanism involving protein tyrosine phosphatase 1B.
Double stimuli-responsive functionalized cellulose nanocrystal-poly[2-(dimethylamino)ethyl methacrylate] (CNC-g-PDMAEMA) reinforced poly(3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV) electrospun composite membranes were explored as drug delivery vehicles using tetracycline hydrochloride (TH) as a model drug. It was found that rigid CNC-g-PDMAEMA nanoparticles enhanced thermal, crystallization and hydrophilic properties of PHBV. Moreover, great improvements in fiber diameter uniformity, crystallization ability and maximum decomposition temperature (Tmax) could be achieved at 6 wt% CNC-g-PDMAEMA. Furthermore, by introducing stimuli-responsive CNC-g-PDMAEMA nanofillers, intelligent and long-term sustained release behavior of composite membranes could be achieved. The releasing mechanism of composite membranes based on zero order, first order, Higuchi and Korsmeyere-Peppas mathematical models was clearly demonstrated, giving effective technical guidance for practical drug delivery systems.
- MeSH
- Cellulose chemistry MeSH
- Hydrophobic and Hydrophilic Interactions MeSH
- Crystallization MeSH
- Membranes chemistry MeSH
- Methacrylates chemistry MeSH
- Nanoparticles chemistry MeSH
- Nanocomposites chemistry MeSH
- Nylons chemistry MeSH
- Models, Theoretical MeSH
- Temperature MeSH
- Drug Liberation * MeSH
- Publication type
- Journal Article MeSH
Endothelin-1 (ET-1) and Nerve Growth Factor (NGF) are proteins, released from cancer-ridden tissues, which cause spontaneous pain and hypersensitivity to noxious stimuli. Here we examined the electrophysiological and behavioral effects of these two agents for evidence of their interactions. Individual small-medium cultured DRG sensory neurons responded to both ET-1 (50 nM, n=6) and NGF (100 ng/ml, n=4), with increased numbers of action potentials and decreased slow K(+) currents; pre-exposure to ET-1 potentiated NGF´s actions, but not vice versa. Behaviorally, single intraplantar (i.pl.) injection of low doses of ET-1 (20 pmol) or NGF (100 ng), did not increase hindpaw tactile or thermal sensitivity, but their simultaneous injections sensitized the paw to both modalities. Daily i.pl. injections of low ET-1 doses in male rats caused tactile sensitization after 21 days, and enabled further tactile and thermal sensitization from low dose NGF, in ipsilateral and contralateral hindpaws. Single injections of 100 ng NGF, without changing the paw's tactile sensitivity by itself, acutely sensitized the ipsilateral paw to subsequent injections of low ET-1. The sensitization from repeated low ET-1 dosing and the cross-sensitization between NGF and ET-1 were both significantly greater in female than in male rats. These findings reveal a synergistic interaction between cutaneously administered low doses of NGF and ET-1, which could contribute to cancer-related pain.
- MeSH
- Pain chemically induced metabolism MeSH
- Endothelin-1 administration & dosage metabolism toxicity MeSH
- Physical Stimulation adverse effects MeSH
- Touch drug effects physiology MeSH
- Injections, Subcutaneous MeSH
- Rats MeSH
- Pain Measurement methods MeSH
- Nerve Growth Factor administration & dosage metabolism toxicity MeSH
- Rats, Sprague-Dawley MeSH
- Protein Binding physiology MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The interaction between retinoids and transforming growth factor-beta1 (TGF-beta1) leading to regulation of proliferation, differentiation and apoptosis is not still fully understood. In this study, we demonstrated that a combination treatment with all-trans retinoic acid (ATRA) and TGF-beta1 led to the enhancement of ATRA-induced suppression of cell proliferation, which is accompanied by inhibition of ATRA-induced apoptosis in human leukemia HL-60 cells. This effect was preceded by the arrest of cells in G0/G1 cell cycle phase linked with pRb protein dephosphorylation, continuous accumulation of p21 and transiently increased level of p27, inhibitors of cyclin-dependent kinases. Inhibition of ATRA-induced apoptosis by TGF-beta1 was associated with an increased level of Mcl-1 protein, an anti-apoptotic member of Bcl-2 family, but not with inhibition of mitochondrial membrane depolarization. Levels of other Bcl-2 family proteins (Bcl-2, Bcl-X(L), Bad, Bak, Bax) were unaffected by simultaneous ATRA and TGF-beta1 treatment, when compared to ATRA alone. Upregulation of c-FLIP(L) protein, an inhibitor of apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), correspond with inhibition of ATRA-induced (autocrine TRAIL-mediated) caspase-8 activation and apoptosis. These results suggest that apoptosis inhibition associated with proliferation block could depend on modulation of the TRAIL apoptotic pathway and regulation of the Mcl-1 protein level. In summary, we demonstrate that the balance of processes leading to regulation of proliferation and differentiation of myeloid cells can modulate cell sensitivity to apoptosis-inducing stimuli.
- MeSH
- Enzyme Activation radiation effects MeSH
- CD11b Antigen physiology drug effects MeSH
- Cell Differentiation drug effects MeSH
- Cell Cycle drug effects MeSH
- CASP8 and FADD-Like Apoptosis Regulating Protein MeSH
- Phosphorylation MeSH
- Resting Phase, Cell Cycle drug effects MeSH
- G1 Phase drug effects MeSH
- Granulocytes physiology drug effects MeSH
- HL-60 Cells MeSH
- Cyclin-Dependent Kinase Inhibitor p21 biosynthesis drug effects MeSH
- Intracellular Signaling Peptides and Proteins pharmacology metabolism MeSH
- Caspase 3 MeSH
- Caspase 8 MeSH
- Caspases metabolism drug effects MeSH
- Humans MeSH
- Membrane Glycoproteins pharmacology metabolism MeSH
- Mitochondrial Membranes physiology drug effects MeSH
- Tumor Cells, Cultured MeSH
- Neoplasm Proteins metabolism drug effects MeSH
- Cell Proliferation drug effects MeSH
- TNF-Related Apoptosis-Inducing Ligand MeSH
- bcl-2-Associated X Protein metabolism drug effects MeSH
- Apoptosis Regulatory Proteins pharmacology metabolism MeSH
- Proto-Oncogene Proteins c-bcl-2 metabolism drug effects MeSH
- Reactive Oxygen Species metabolism MeSH
- Retinoblastoma Protein metabolism drug effects MeSH
- Drug Synergism MeSH
- Tumor Necrosis Factor-alpha pharmacology metabolism MeSH
- Transforming Growth Factor beta pharmacology MeSH
- Transforming Growth Factor beta1 MeSH
- Tretinoin antagonists & inhibitors pharmacology MeSH
- Cell Survival drug effects MeSH
- Check Tag
- Humans MeSH
Growth of the remnant embryonic kidney (the mesonephros), as expressed by wet weight, was more rapid in the chick embryos with experimentally induced unilateral renal agenesis compared to controls. The difference was significant between embryonic days 8-12, when the doubled weights of remnant kidneys were increased compared with the weights of paired control kidneys. The excessive growth of the mesonephros ceased on day 14, when the normal physiological regression of the embryonic kidney begins. In the definitive kidney, the metanephros, no significant differences in weights of the control vs. remnant metanephros were found on days 10-14. The characteristics of increased mesonephric growth were evaluated by determination of DNA/protein ratios in homogenates of the kidneys. Significant cellular hypertrophy was found in both the mesonephros and metanephros of the embryos with URA on day 10. Additionally, a non-significant cellular hyperplasia was also revealed in the remnant mesonephros on day 8. This gives evidence that the growth stimuli to the mesonephroi were probably strongest between days 8-10 and that they manifested in the remnant mesonephros only.
- MeSH
- DNA physiology isolation & purification MeSH
- Financing, Organized utilization MeSH
- Data Interpretation, Statistical MeSH
- Chick Embryo physiology physiopathology growth & development MeSH
- Kidney physiology growth & development MeSH
- Mesonephros physiology growth & development MeSH
- Nephrectomy methods utilization MeSH
- Proteins physiology isolation & purification MeSH
- Check Tag
- Chick Embryo physiology physiopathology growth & development MeSH
