Dead Cells Research Articles

Comparison of cytotoxicity methods for studying Vipera ammodytes venom and the anticytotoxic potency of antivenom.

Alternative in vitro tests that can be used instead of animal experiments are those that can most closely evaluate the biological activity of the drug of interest. For testing the potency of antivenom, these are the methods used to assess cytotoxicity. The aim of this study was to evaluate the most commonly used cytotoxicity methods for determining the protective potency of the antivenom Viekvin, which neutralizes Vipera ammodytes venom. The selected methods are based on different biological mechanisms: MTT assay, based on the activity of cell oxidoreductase enzymes; crystal violet staining, based on the degree of cell adhesion; trypan blue staining, based on cell membrane permeability, and propidium iodide staining, based on measurement of nucleic acids of dead cells. The pro-apoptotic effect of the venom was also determined with annexin V staining. The IC50 value of V. ammodytes venom obtained by these methods was very similar, while the EC50 values differed significantly. We concluded that the choice of the method used to measure the anticytotoxic anti-venom potency depends on the immunogenicity of the venom components that cause cell death; for each venom/antivenom pair, it is necessary to select the appropriate assay separately, and at present, none of the standard cytotoxic methods can be universally applied to determine antivenom potency.

Epigenetic integration of signaling from the regenerative environment.

Skeletal muscle has an extraordinary capacity to regenerate itself after injury due to the presence of tissue-resident muscle stem cells. While these muscle stem cells are the primary contributor to the regenerated myofibers, the process occurs in a regenerative microenvironment where multiple different cell types act in a coordinated manner to clear the damaged myofibers and restore tissue homeostasis. In this regenerative environment, immune cells play a well-characterized role in initiating repair by establishing an inflammatory state that permits the removal of dead cells and necrotic muscle tissue at the injury site. More recently, it has come to be appreciated that the immune cells also play a crucial role in communicating with the stem cells within the regenerative environment to help coordinate the timing of repair events through the secretion of cytokines, chemokines, and growth factors. Evidence also suggests that stem cells can help modulate the extent of the inflammatory response by signaling to the immune cells, demonstrating a cross-talk between the different cells in the regenerative environment. Here, we review the current knowledge on the innate immune response to sterile muscle injury and provide insight into the epigenetic mechanisms used by the cells in the regenerative niche to integrate the cellular cross-talk required for efficient muscle repair.

Chapter 2 - History of cellular grafting for central nervous system repair—A clinical perspective

As late as in the 1970s, the evidence supporting that brain function might be restored by replacing dead cells by transplantation of new healthy cells was scarce in experimental animals and lacking in humans. Repairing the human brain was regarded as completely unrealistic by clinicians. Fifty years later, the situation is very different, and cellular grafting has reached patient application in several conditions affecting the CNS. The clinical studies performed so far have shown that cellular grafts can survive, grow, and function also in the diseased adult human brain. However, no proven treatment based on cell transplantation is currently available for any brain disorder. Here, the history of cellular grafting is described from a clinical perspective, including some of the preclinical work that has formed the basis for its translation to patient application. The focus is on cell transplantation for Parkinson disease, which in many ways is paving the way for this field of research. The chapter gives an account of the scientific milestones, the ups and downs, as well as the positive and negative reactions from the scientific and clinical community, and how this research field despite many obstacles has continued to move forward over more than four decades.

Planarians require ced-12/elmo-1 to clear dead cells by excretion through the gut

Cell corpse removal is a critical component of both development and homeostasis throughout the animal kingdom. Extensive research has revealed many of the mechanisms involved in corpse removal, typically involving engulfment and digestion by another cell; however, the dynamics of cell corpse clearance in adult tissues remain unclear. Here, we track cell death in the adult planarian Schmidtea mediterranea and find that, following light-induced cell death, pigment cell corpses transit to the gut and are excreted from the animal. Gut phagocytes, previously only known to phagocytose food, are required for pigment cells to enter the gut lumen. Finally, we show that the planarian ortholog of ced-12/engulfment and cell motility (ELMO) is required for corpse phagocytosis and removal through the gut. In total, we present a mechanism of cell clearance in an adult organism involving transit of dead cells to the gut, transport into the gut by phagocytes, and physical excretion of debris.

Preparation and evaluation of a niosomal delivery system containing G. mangostana extract and study of its anti-Acanthamoeba activity.

Garcinia mangostana extract (GME) has severe pharmacokinetic deficiencies and is made up of a variety of bioactive components. GME has proven its anti-Acanthamoeba effectiveness. In this investigation, a GME-loaded niosome was developed to increase its potential therapeutic efficacy. A GME-loaded niosome was prepared by encapsulation in a mixture of span60, cholesterol, and chloroform by the thin film hydration method. The vesicle size, zeta potential, percentage of entrapment efficiency, and stability of GME-loaded niosomes were investigated. The values for GME-loaded niosome size and zeta potential were 404.23 ± 4.59 and -32.03 ± 0.95, respectively. The delivery system enhanced the anti-Acanthamoeba activity, which possessed MIC values of 0.25-4 mg mL-1. In addition, the niosomal formulation decreased the toxicity of GME by 16 times. GME-loaded niosome must be stored at 4 °C, as the quantity of remaining GME encapsulated is greater at this temperature than at room temperature. SEM revealed the damage to the cell membrane caused by trophozoites and cysts, which led to dead cells. In light of the above, it was found that GME-loaded niosomes had better anti-Acanthamoeba activity. The study suggested that GME-loaded niosomes could be used as an alternative to Acanthamoeba's therapeutic effects.

Crosstalk between CD8+ T cells and mesenchymal stromal cells in intestine homeostasis and immunity.

The intestine represents the most complex cellular network in the whole body. It is constantly faced with multiple types of immunostimulatory agents encompassing from food antigen, gut microbiome, metabolic waste products, and dead cell debris. Within the intestine, most T cells are found in three primary compartments: the organized gut-associated lymphoid tissue, the lamina propria, and the epithelium. The well-orchestrated epithelial-immune-microbial interaction is critically important for the precise immune response. The main role of intestinal mesenchymal stromal cells is to support a structural framework within the gut wall. However, recent evidence from stromal cell studies indicates that they also possess significant immunomodulatory functions, such as maintaining intestinal tolerance via the expression of PDL1/2 and MHC-II molecules, and promoting the development of CD103+ dendritic cells, and IgA+ plasma cells, thereby enhancing intestinal homeostasis. In this review, we will summarize the current understanding of CD8+ T cells and stromal cells alongside the intestinal tract and discuss the reciprocal interactions between T subsets and mesenchymal stromal cell populations. We will focus on how the tissue residency, migration, and function of CD8+ T cells could be potentially regulated by mesenchymal stromal cell populations and explore the molecular mediators, such as TGF-β, IL-33, and MHC-II molecules that might influence these processes. Finally, we discuss the potential pathophysiological impact of such interaction in intestine hemostasis as well as diseases of inflammation, infection, and malignancies.

Microglial Uptake of Extracellular Tau by Actin-Mediated Phagocytosis.

Microglia are scavengers of the brain environment that clear dead cells, debris, and microbes. In Alzheimer's disease, microglia get activated to phagocytose damaged neurons, extracellular Amyoid-β, and Tau deposits. Several Tau internalization mechanisms of microglia have been studied which include phagocytosis, pinocytosis, and receptor-mediated endocytosis. In this chapter, we have visualized microglial phagocytic structures that are actin-rich cup-like extensions, which surrounds extracellular Tau species by wide-field fluorescence and confocal microscopy. We have shown the association of filamentous actin in Tau phagocytosis along the assembly of LC-3 molecules to phagosomes. The 3-dimensional, orthogonal and gallery wise representation of these phagocytic structures provides an overview of the phagocytic mechanism of extracellular Tau by microglia.

Reactive oxygen species generation required for autophagy induction during butyrate- or propionate-induced release of damage-associated molecular patterns from dying gingival epithelial Ca9-22 cells.

Bacterial cells in mature dental plaque produce a high concentration of short-chain fatty acids (SCFAs) such as butyrate and propionate. SCFA-treatment on human gingival epithelial Ca9-22 cells induced cell death. However, the exact mechanism underlying cell death remains unclear. In this study, the relationship between reactive oxygen species (ROS) and autophagy induction during SCFA-induced cell death was examined. Human gingival epithelial Ca9-22 cells were treated with butyrate or propionate to induce cell death and the number of dead cells were measured using SYTOX-green dye. A siRNA for ATG5 and N-acetylcysteine (NAC) were used for autophagy reduction and ROS-scavenging, respectively. Release of damage-associated molecular patterns (DAMPs) such as Sin3A-associated protein 130 (SAP130) and high-mobility group box 1 (HMGB1) were detected using western blot. Reducing autophagy significantly suppressed SCFA-induced Ca9-22 cell death. ROS generation was observed upon SCFA treatment, and scavenging ROS with NAC decreased cell death. NAC also reduced the SCFA-induced increase in microtubule-associated protein 1 light chain 3B (LC3B)-I and LC3B-II, and mitigated the release of DAMPs. The findings suggest that ROS generation is necessary for autophagy, which is required for SCFA-induced cell death and accompanying DAMP release.

Improvement of osteoblast adhesion, viability, and mineralization by restoring the cell cytoskeleton after bisphosphonate discontinuation in vitro.

Bisphosphonates are prescribed to treat excessive bone resorption in patients with osteoporosis. However, its use is associated with potential adverse effects such as medication-related osteonecrosis of the jaw, prompting the introduction of the drug holiday concept in patients prior to dentoalveolar surgery. Furthermore, bisphosphonate discontinuation has been studied in vivo, in humans, and in animal models. However, it is not known whether this approach could affect bone cells in vitro. Therefore, the objective of this study was to investigate the potential effects of bisphosphonate discontinuation on pre-osteoblast and osteoblast activities in vitro. Pre-osteoblasts (MC3T3) and osteoblasts were treated with bisphosphonate (alendronate) at concentrations of 1, 5, and 10 µM. Alendronate was then withdrawn at different time points. The negative control consisted of untreated cells (0 µM), while the positive control consisted of cells incubated with alendronate throughout the experiment. Cell viability, cell adhesion, cell cytoskeleton, mineralization, and gene expressions were investigated. Pre-osteoblasts and osteoblasts showed a decrease in cell viability after treatment with 5-10 μM alendronate for 4 days or longer. Two days of alendronate discontinuation significantly increased cell viability compared with the positive control. However, these levels did not reach those of the negative control. Bone nodule formation was reduced by alendronate. Discontinuation of alendronate regained bone nodule formation. Longer periods of discontinuation were more effective in restoring nodule formation than shorter periods. Addition of alendronate resulted in an increase in the percentage of dead cells, which, in turn, decreased when alendronate was discontinued. Alendronate affected the cell cytoskeleton by disassembling actin stress fibers. Cell adhesion and cell morphological parameters were also affected by alendronate. Discontinuation of alendronate restored cell adhesion and these parameters. Overall, the highest improvement after alendronate discontinuation was seen at 10 µM. However, alendronate treatment and discontinuation did not affect osteoblast gene expression. Discontinuation of alendronate helps to reverse the negative effects of the drug on cell viability, cell adhesion, and mineralization by restoring the cell cytoskeleton. Our data suggest the benefits of drug holiday and/or intermittent strategies for alendronate administration at the cellular level.

A Biomimetic Nanocarrier Strategy Targets Ferroptosis and Efferocytosis During Myocardial Infarction.

Myocardial infarction (MI) is characterized by irreversible cardiomyocyte death resulting from an inadequate supply of oxygenated blood to the myocardium. Recent studies have indicated that ferroptosis, a form of regulated cell death, exacerbates myocardial injury during MI. Concurrently, the upregulation of CD47 on the surface of damaged myocardium following MI impairs the clearance of dead cells by macrophages, thereby hindering efferocytosis. In this context, simultaneously inhibiting ferroptosis and enhancing efferocytosis may represent a promising strategy to mitigate myocardial damage post-MI. In this study, we engineered platelet membrane-coated hollow mesoporous silicon nanoparticles (HMSN) to serve as a drug delivery system, encapsulating ferroptosis inhibitor, Ferrostatin-1, along with an anti-CD47 antibody. We aimed to assess the potential of these nanoparticles (designated as Fer-aCD47@PHMSN) to specifically target the site of MI and evaluate their efficacy in reducing cardiomyocyte death and inflammation. The platelet membrane coating on the nanoparticles significantly enhanced their ability to successfully target the site of myocardial infarction (MI). Our findings demonstrate that treatment with Fer-aCD47@PHMSN resulted in a 38.5% reduction in cardiomyocyte ferroptosis under hypoxia, indicated by decreased lipid peroxidation and increased in vitro. Additionally, Fer-aCD47@PHMSN improved cardiomyocyte efferocytosis by approximately 15% in vitro. In MI mice treated with Fer-aCD47@PHMSN, we observed a substantial reduction in cardiomyocyte death (nearly 30%), decreased inflammation, and significant improvement in cardiac function. Our results demonstrated that the cooperation between the two agents induced anti-ferroptosis effects and enhanced dead cardiomyocyte clearance by macrophage as well as anti-inflammation effects. Thus, our nanoparticle Fer-aCD47@PHMSN provides a new therapeutic strategy for targeted therapy of MI.

Green synthetic photo-irradiated chitin-silver nanoparticles for antimicrobial applications

The primary purpose of this study was to synthesize silver nanoparticles (AgNPs) utilizing chitin extracted from shrimp shell waste by simple photo-irradiation in a single-pot biosynthesis without adding any toxic chemical substances. Glucose molecules in the chitin extract act as the reducing agent, while amino acids in chitin behave like proteins and are responsible for the production of AgNPs by acting as the particle-stabilizing agent. The synthesized chitin-AgNPs were thoroughly investigated using transmission electron microscopy (TEM), Fourier-transform infrared analysis, and ultraviolet-visible absorption spectroscopy. UV-visible spectroscopy revealed a surface plasmon resonance peak at 470 nm, confirming the formation of chitin-AgNPs. FTIR data confirmed the association between chitin and AgNPs. TEM studies showed that the synthesized chitin-AgNPs have a spherical shape with particle sizes ranging from 10 to 30 nm. The prepared chitin-AgNPs exhibited intense antibacterial activity against the Gram-positive Bacillus subtilis, Staphylococcus aureus, Gram-negative Pseudomonas aeruginosa, and Escherichia coli, as well as antifungal efficacy against Aspergillus niger. Reactive oxygen species and live and dead cell assays were performed to examine the chitin- AgNPs and the results were further found to be interesting and positive. The assays revealed that the prepared chitin- AgNPs exhibited significant antimicrobial potential against B. subtilis and A. niger, with a zone of inhibition measuring approximately 6.2 mm and 30 mm, respectively. The effects of the chitin-AgNPs were compared to those of commercial agents, such as ciprofloxacin (6.0 mm) and fluconazole (25 mm). Consequently, the chitin-AgNPs developed through a greener approach show promising potential as sustainable materials for antibacterial and antifungal activities.

Comparing Flow Cytometry and ELISpot for Detection of IL-10, IL-6, and TNF Alpha on Human PBMCs.

ELISpot and flow cytometry are two methods often utilized side-by-side for detecting secreted and intracellular cytokines, respectively. Each application has its own advantages and challenges. ELISpot is more sensitive compared to ELISA and appears to be more consistent in detecting IL-10 production than flow cytometry. ELISpot can be used for detecting the secretion of multiple cytokines but not from the same cells simultaneously, whereas flow cytometry allows for the concurrent detection of multiple intracellular cytokines by the same cells. Flow cytometry is a convenient technique allowing for the detection of many cytokines at the same time in a population of cells. The restimulation cocktails used for cytokine detection in flow cytometry are hard on cells and lead to decreased cell viability. Using a live dead dye allows for the exclusion of dead cells when analyzing data. We illustrated the differences between ELISpot and flow cytometry by stimulating cells with two toll-like receptor (TLR) agonists, LPS or Pam3CSK4. Both activators increase production of various cytokines, including IL-10, IL-6, and TNF-alpha. The TLR2 antagonist, MMG-11, was used to inhibit this increased cytokine production. We observed some inhibition of IL-6 and IL-10 from Pam3CSK4 stimulation in the presence of MMG-11 by flow cytometry. TNF-α remains largely unchanged as its basal expression is high, but there is some reduction in the presence of MMG-11 for both methods. However, IL-10 was difficult to detect by ELISpot given the low seeding density. Overall, both ELISpot and flow cytometry are good methods for detecting secreted and intracellular cytokines, respectively, and should be used as complimentary assays.

Analysis of multiyear seasonal spatial-temporal chlorophyll-a concentration dynamics in the coastal zone of north-western of the Sea of Japan

The coastal zone and shelf of the north-western of the Sea of Japan have high biological productivity. The vegetation of microalgae is realized due to insolation, nutrient input with river runoff and as a result of seasonal vertical mixing of water masses. Also, the productivity activity relates to the type of marine landscape. Phytoplankton assemblages are first-order food resources for zooplankton and the second for nekton (fish, mammals), and they also serve as a source of biological minerals from the decayed of their dead cell products, which as suspended particles (detritus) provide food for pelagic bacteria and bottom biocenoses. The vertical subdivision of the landscape - neritho-pelagial (coastal zone) of the studied part of the sea reflects a wide biological diversity represented by bottom communities of living organisms. The research objective of this article studied to analyze the spatial and temporal dynamics of chlorophyll-a concentration in phytoplankton in different landscape-bionomic areas in the north- western of the Sea of Japan for each season from 2003 to 2022’s. The article is used the landscape-bionomic and space monitoring data approaches. The known system of units of global zoning of ecoregions (sea basins) describes the natural features of the sea. The fundamental unit of regional zoning is coastal morphostructures or marine landscape which builds ecological conditions for hydrobionts. Space monitoring from the Aqua satellite, NASA, covers the upper layers of water at a wide resolution. Water surface temperature and chlorophyll-a concentration for 20 years (2003-2022's) are compared on the basis of satellite data. Practical significance: the paper discloses the links between landscape-bionomic areas and seasonal multiyear dynamics of temperature and phytoplankton productivity in the north- western of the Sea of Japan. The comprehensive approach will serve as a necessity for the rational use of aquatic biological resources. Moreover, satellite data can be applied to the construction of long-term forecasts of climate variability in the region.

A novel in vitro model of clinical cryoablation to investigate the transition zone for focal tumor ablation

Cryoablation (CA) of solid tumors is highly effective at reducing tumor burden and eliminating small, early stage tumors. However, complete ablation is difficult to achieve and cancer recurrence is a significant barrier to treatment of larger tumors compared to resection. In this study, we explored the relationship between temperature, ice growth, and cell death using a novel in vitro model of clinical CA with the Visual-ICE (Boston Scientific) system, a clinically approved and widely utilized device. We found that increasing the duration of freezing from 1 to 2 min increased ice radius from 3.44 ± 0.13 mm to 5.29 ± 0.16 mm, and decreased the minimum temperature achieved from −22.8 ± 1.3 °C to −45.5 ± 7.9 °C. Furthermore, an additional minute of freezing increased the amount of cell death within a 5 mm radius from 42.5 ± 8.9% to 84.8 ± 1.1%. Freezing at 100% intensity leads to faster temperature drops and a higher level of cell death in the TRAMP-C2 mouse prostate cancer cell line, while lower intensities are useful for slow freezing, but result in less cell death. The width of transition zone between live and dead cells decreased by 0.4 ± 0.2 mm, increasing from one to two cycles of freeze/thaw cycles at 100% intensity. HMGB-1 levels significantly increased with 3 cycles of freeze/thaw compared to the standard 2 cycles. Overall, a longer freezing duration, higher freezing intensity, and more freeze thaw cycles led to higher levels of cancer cell death and smaller transition zones. These results have the potential to inform future preclinical research and to improve therapeutic combinations with CA.

High-throughput selection of sperm with improved DNA integrity and rapidly progressive motility using a butterfly-shaped chip compared to the swim-up method.

Microfluidics provides unique opportunities for the high throughput selection of motile sperm with improved DNA integrity for assisted reproductive technologies (ARTs). Here, through a parametric study on dimensions and geometrical angles, a butterfly-shaped chip (BSC) is presented to isolate sperm with high progressive motility and intact DNA at a separation rate of 1125 sperm per minute. Using finite element simulations, the flow field and shear rates in the device were optimized to leverage the inherent motility characteristics of sperm for maximum selection throughput. The device incorporates a triple selection mechanism in series, initially activating sperm rheotaxis by rotation against the semen flow, penetrating the counter buffer flow and swimming against the direction of the buffer flow, leaving dead cells and debris behind, and subsequently leveraging boundary-following behavior to direct progressively motile sperm to swim along the walls and reach the device outlet. The device selects over 4.1 million sperm per mL within 20 minutes, with 29.2%, 68.2%, and 57.3% improvement in total motility, DNA integrity, and velocity parameter (VCL), as compared with the conventional swim-up method, respectively. Overall, the performance of the device to separate sperm with approximately 95.9% total motility, 97.8% viability, and 96.6% DNA integrity at high concentrations demonstrates its potential for enhancing the efficiency of conventional treatment methods.

Effect of extenders, cryoprotectants and dilution ratios on the spermatological properties of cryopreserved milt of cobia Rachycentron canadum

Cobia (Rachycentron canadum) culture depends on the availability of seeds which isaffected by asynchronous spawning and brooders availability. The possible solution forthese problems is the use of cryopreserved, high quality gametes from selected individuals.Therefore, in the present study, the effect of different extenders, different concentrationsof cryoprotectants and dilution ratios on the spermatological properties of cryopreservedcobia milt was analysed. Milt was collected from R. canadum brooders and diluted withMarine Fish Ringer’s Solution (MFRS) and 0.85% physiological saline (PS) as extendersand dimethyl sulphoxide (DMSO) as cryoprotectant at three different concentrations(5, 10 and 15%) at three dilution ratios such as 1:5, 1:10 and 1:15. Motility duration, motilitypattern, motility score and percentage of live and dead cells were analysed. The milt wasrapidly frozen employing liquid nitrogen vapour for 10 min. The milt sample diluted with PSand 10% DMSO at 1:5 dilution ratio exhibited highest post-thaw motility parameters. Keywords:Cryoprotectants, Cryopreservation, Dilution ratios, Extenders, Spermatological properties, Rachycentron canadum

SİNİR BÜYÜME FAKTÖRÜ İLE FARKLILAŞTIRILMIŞ PC12 HÜCRELERİNİN MORFOMETRİK VE FLORESANS ANALİZİ

Objective
 PC12 is a rat pheochromocytoma cell line. These
 cells characteristically undergo differentiation when
 cultured with nerve growth factor (NGF). Depending
 on the dose of NGF, the length of neurite extensions
 changes. Thanks to this differentiation property,
 the cells are used in neuroscience and in modeling
 pathophysiological diseases such as Alzheimer's,
 Parkinson's, and Amyotrophic Lateral Sclerosis.
 However, literature studies showing the effect of NGF
 on neurite extensions formed in PC12 cells are very
 limited. This study aimed to investigate the effect of
 NGF on neurite extensions and cell viability depending
 on dose and incubation time.
 Materials and Methods
 In this study, PC12 cells were incubated with 50 ng/ml
 and 100 ng/ml NGF for 3, 6 and 7 days. The lengths
 of neurite outgrowths and dead cell ratios were
 calculated in incubated cells.
 Results
 The results showed that the length of neurite
 extensions and dead cell ratio increased depending
 on NGF doses and incubation time. When NGF
 incubation times were compared, no difference was
 found between 50 ng/ml NGF 6 days and 100 ng/ml
 NGF 3 days groups.
 Conclusion
 When the dead cell ratios and sizes of neurite
 extensions in the experimental groups are evaluated,
 it is thought that 100 ng/ml NGF and 3 days incubation
 time parameters are ideal for PC12 cell differentiation.

BAG2 and MAPK2 regulate differently on different periods of heat-induced programmed cell death in tomato

High temperature is a significant abiotic stress that affects growth and development of plants. BAG (Bcl-2 associated athanogene) protein family members act as co-chaperones and apoptosis inhibitors in multiple cellular processes. BAG, MAPK (Mitogen-activated protein kinase), and programmed cell death (PCD) play critical roles in plant growth and development, stress response, and disease resistance. In this study, we investigated the interaction of BAG, and MAPK as well as their putative role in PCD under either short or long-term heat stress. We constructed mutants of bag2 and mapk2 in tomato using CRISPR/Cas9. Our results revealed that tomato BAG2 and MAPK2 interacted positively both in vivo and in vitro. In addition, after 3 h of heat stress, the activities of Caspase 3 and antioxidant enzymes, expression levels of Caspase 3 and Caspase 9, and contents of H2O2 in bag2 and mapk2 mutant plants were lower than those in WT (wild type) plants. Moreover, under short-term (3 h) heat stress, the DNA fragmentation phenomena and trypan blue coloration in both mutants were less severe than in WT plants; however, DNA integrities were broken, and the number of dead cells was higher under long-term (24 h) heat stress. Additionally, the electrolyte leakage was increased, but the Fv/Fm (maximum photochemical efficiency) value was decreased in mutants following exposure to heat stress. These results suggested that tomato BAG2 and MAPK2 suppressed short-time heat-induced PCD while promoting long-time heat-induced PCD.

The Velamen Radicum Is Common in the Genus Anthurium, Both in the Epiphytic and Terrestrial Species

The velamen radicum, a rhizodermis that consists of dead cells at maturity, is often described as typical for epiphytic aroids. Such claims are surprising on two grounds: (1) there are hardly any data on this trait for aroids and (2) the link between a velamen and epiphytic growth has recently been challenged in general. We performed an anatomical and histological study with 82 Anthurium species and analyzed the occurrence of a velamen in regard to habit (epiphytic vs. terrestrial) and phylogenetic relatedness. Almost 90% of both epiphytic and terrestrial species had a velamen. The number of cell layers comprising this tissue were also very similar in both groups. The most likely interpretation of the phylogenetic tree suggests that a velamen is not ancestral in Anthurium. It was gained once and has been lost several times during diversification of the genus. Our results are an important contribution to the current discussion on the possible function of the velamen. While there is some experimental evidence for its importance for epiphytic plants, its role in terrestrial plants is completely unresolved.

Dipotassium glycyrrhizate and hinokitiol enhance macrophage efferocytosis by regulating recognition, uptake, and metabolism of apoptotic cells invitro.

Efferocytosis is a process whereby macrophages remove apoptotic cells, such as neutrophils, that have accumulated in tissues, which is required for resolution of inflammation. Efferocytosis is impaired in individuals with increasing age and in those with various systemic diseases. Recently, efferocytosis has been reported to be related to the pathogenesis and progression of periodontitis, and enhancement of efferocytosis, especially in the subjects with impaired efferocytosis, was suggested to lead to periodontitis prevention and care. Various anti-inflammatory ingredients are used in oral care products, but their effect on efferocytosis is unclear. Here, we aimed to identify ingredients contained in oral care products that are effective for efferocytosis regulation. The ability of dead cells to induce inflammation in human gingival fibroblast (HGF) cells were evaluated by measuring IL-6 secretion. Six ingredients in oral care products used as anti-inflammatory agents were evaluated for their effect on efferocytosis using flow cytometry. The expression of various efferocytosis-related molecules, such as MERTK and LRP1 involved in recognition, and LXRα and ABCA1 that function in metabolism, were measured in RAW264.7 cells with or without ingredient treatment. Rac1 activity, which is related to the uptake of dead cells, was measured using the G-LISA kit. Dead cells elicited IL-6 secretion in HGF cells. Among the six ingredients, GK2 and hinokitiol enhanced efferocytosis activity. GK2 and hinokitiol significantly increased the expression of MERTK and LRP1, and also enhanced LXRα and ABCA1 expression after efferocytosis. Furthermore, they increased Rac1 activity in the presence of dead cells. Among the six ingredients tested, GK2 and hinokitiol promoted efferocytosis by regulating apoptotic cell recognition, uptake, and metabolism-related molecules. Efferocytosis upregulation may be one of the mechanisms of GK2 and hinokitiol in the treatment of inflammatory diseases, such as periodontitis.