scholarly journals Cell death-inducing cytotoxicity in truncated KCNQ4 variants associated with DFNA2 hearing loss

2021 ◽  
Author(s):  
Takashi Kojima ◽  
Koichiro Wasano ◽  
Satoe Takahashi ◽  
Kazuaki Homma
Keyword(s):  
Cell Death ◽  
Hearing Loss ◽  
Inhibitory Effect ◽  
Dominant Negative ◽  
Dominant Inheritance ◽  
Causative Gene ◽  
Cytotoxic Effects ◽  
Pathological Mechanism ◽  
Voltage Dependent ◽  
Heterologous Expression Systems

KCNQ4 encodes the homotetrameric voltage-dependent potassium ion channel, Kv7.4, and is the causative gene for autosomal dominant nonsyndromic sensorineural hearing loss, DFNA2. Dominant-negative inhibition accounts for the observed dominant inheritance of many DFNA2-associated KCNQ4 variants. In addition, haploinsufficiency has been presumed as the pathological mechanism for truncated Kv7.4 variants lacking the C-terminal tetramerization region, as they are unlikely to exert a dominant-negative inhibitory effect. Such truncated Kv7.4 variants should result in relatively mild hearing loss when heterozygous; however, this is not always the case. In this study, we characterized Kv7.4Q71fs (c.211delC), Kv7.4W242X (c.725G>A), and Kv7.4A349fs (c.1044_1051del8) in heterologous expression systems and found that expressions of these truncated Kv7.4 variants induce cell death. We also found similar cell death-inducing cytotoxic effects in truncated Kv7.1 (KCNQ1) variants, pointing to the generality of our finding that could account for the dominant inheritance of many, if not most, truncated Kv7 variants. Moreover, we found that the application of autophagy inducers can ameliorate the cytotoxicity, providing a novel insight for the development of alternative therapeutic strategies for Kv7.4 variants.

scholarly journals Dominant negative connexin26 mutation R75W causing severe hearing loss influences normal programmed cell death in postnatal organ of Corti

BMC Genetics ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 1 ◽  
Author(s):  
Ayako Inoshita ◽  
Keiko Karasawa ◽  
Megumi Funakubo ◽  
Asuka Miwa ◽  
Katsuhisa Ikeda ◽  
...  
Keyword(s):  
Cell Death ◽  
Hearing Loss ◽  
Programmed Cell Death ◽  
Organ Of Corti ◽  
Dominant Negative ◽  
Severe Hearing Loss

scholarly journals Peppers: A “Hot” Natural Source for Antitumor Compounds

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1521
Author(s):  
Micael Rodrigues Cunha ◽  
Maurício Temotheo Tavares ◽  
Thais Batista Fernandes ◽  
Roberto Parise-Filho
Keyword(s):  
Cell Death ◽  
Cellular Responses ◽  
Biological Applications ◽  
Traditional Use ◽  
Cytotoxic Effects ◽  
Antiproliferative Effects ◽  
Naturally Occurring ◽  
Antitumor Compounds ◽  
Tumorigenic Cells ◽  
Ancient Civilizations

Piper, Capsicum, and Pimenta are the main genera of peppers consumed worldwide. The traditional use of peppers by either ancient civilizations or modern societies has raised interest in their biological applications, including cytotoxic and antiproliferative effects. Cellular responses upon treatment with isolated pepper-derived compounds involve mechanisms of cell death, especially through proapoptotic stimuli in tumorigenic cells. In this review, we highlight naturally occurring secondary metabolites of peppers with cytotoxic effects on cancer cell lines. Available mechanisms of cell death, as well as the development of analogues, are also discussed.

scholarly journals Voltage-dependent anion channels are dispensable for mitochondrial-dependent cell death

2007 ◽  
Vol 9 (5) ◽  
pp. 550-555 ◽  
Author(s):  
Christopher P. Baines ◽  
Robert A. Kaiser ◽  
Tatiana Sheiko ◽  
William J. Craigen ◽  
Jeffery D. Molkentin
Keyword(s):  
Cell Death ◽  
Anion Channels ◽  
Voltage Dependent ◽  
Dependent Cell

scholarly journals The Phytochemical Analysis of Vinca L. Species Leaf Extracts Is Correlated with the Antioxidant, Antibacterial, and Antitumor Effects

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 3040
Author(s):  
Alexandra Ciorîță ◽  
Cezara Zăgrean-Tuza ◽  
Augustin C. Moț ◽  
Rahela Carpa ◽  
Marcel Pârvu
Keyword(s):  
Bacterial Infections ◽  
Inhibitory Effect ◽  
Total Phenolic ◽  
Phytochemical Analysis ◽  
Leaf Extracts ◽  
Antitumor Effects ◽  
Cytotoxic Effects ◽  
E Coli ◽  
Lactate Dehydrogenase Release ◽  
Nitric Oxide Concentration

The phytochemical analysis of Vinca minor, V. herbacea, V. major, and V. major var. variegata leaf extracts showed species-dependent antioxidant, antibacterial, and cytotoxic effects correlated with the identified phytoconstituents. Vincamine was present in V. minor, V. major, and V. major var. variegata, while V. minor had the richest alkaloid content, followed by V. herbacea. V. major var. variegata was richest in flavonoids and the highest total phenolic content was found in V. herbacea which also had elevated levels of rutin. Consequently, V. herbacea had the highest antioxidant activity followed by V. major var. variegata. Whereas, the lowest one was of V. major. The V. minor extract showed the most efficient inhibitory effect against both Staphylococcus aureus and E. coli. On the other hand, V. herbacea had a good anti-bacterial potential only against S. aureus, which was most affected at morphological levels, as indicated by scanning electron microscopy. The Vinca extracts acted in a dose-depended manner against HaCaT keratinocytes and A375 melanoma cells and moreover, with effects on the ultrastructure, nitric oxide concentration, and lactate dehydrogenase release. Therefore, the Vinca species could be exploited further for the development of alternative treatments in bacterial infections or as anticancer adjuvants.

scholarly journals Phosphatidylinositol-3,4,5-Trisphosphate Is Required for Insulin-Like Growth Factor 1-Mediated Survival of 3T3-L1 Preadipocytes**This work was supported by a grant (to A.S.) from the Medical Research Council of Canada.

Endocrinology ◽  
2001 ◽  
Vol 142 (1) ◽  
pp. 205-212 ◽  
Author(s):  
AnneMarie Gagnon ◽  
Patti Dods ◽  
Nicolas Roustan-Delatour ◽  
Ching-Shih Chen ◽  
Alexander Sorisky
Keyword(s):  
Cell Death ◽  
Growth Factor ◽  
Mammalian Target Of Rapamycin ◽  
Inhibitory Effect ◽  
Tunel Staining ◽  
Insulin Like Growth Factor ◽  
Tissue Mass ◽  
Akt Phosphorylation ◽  
Dependent Cell ◽  
Phosphoinositide 3 Kinase

Abstract Adipocyte number, a determinant of adipose tissue mass, reflects the balance between the rates of proliferation/differentiation vs. apoptosis of preadipocytes. The percentage of 3T3-L1 preadipocytes undergoing cell death following serum deprivation was reduced by 10 nm insulin-like growth factor (IGF)-1 (from 50.0 ± 0.7% for control starved cells to 27.5 ± 3.1%). TUNEL staining confirmed the apoptotic nature of the cell death. The protective effect of IGF-1 was blocked by phosphoinositide 3-kinase (PI3K) inhibitors, wortmannin, and LY294002, but was unaffected by rapamycin, PD98059, or SB203580, which inhibit mammalian target of rapamycin (mTOR), ERK kinase (MEK1), and p38 MAPK respectively. Exogenous PI(3,4,5)P3 (10 μm), the principal product of IGF-1-stimulated PI3K in 3T3-L1 preadipocytes, had a modest survival effect on its own, reducing cell death from 47.9± 3.4% to 35.6 ± 3.5%. When added to the combination of IGF-1 and LY294002, PI(3,4,5)P3 reversed most of the inhibitory effect of LY294002 on IGF-1-dependent cell survival, protein kinase B/Akt phosphorylation, and caspase-3 activity. Taken together, these results implicate PI(3,4,5)P3 as a necessary signal for the anti-apoptotic action of IGF-1 on 3T3-L1 preadipocytes.

Effect of Hypertonic Sucrose Upon the Immune Bactericidal Reaction

1970 ◽  
Vol 1 (1) ◽  
pp. 51-55
Author(s):  
Louis H. Muschel ◽  
Linda J. Larsen
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
Enzymatic Reaction ◽  
Inhibitory Effect ◽  
Lag Phase ◽  
Inner Membrane ◽  
Bactericidal Antibody ◽  
Kinetics Of ◽  
Free Serum ◽  
Supporting Structures

This study was performed to determine the mechanism whereby hypertonic sucrose inhibits the immune bactericidal reaction. Other investigators had postulated that the initial attack of complement (C) on the cell wall was followed with lysozyme-containing whole serum by an enzymatic reaction upon the peptidoglycan substrate resulting in cell death. In the absence of serum lysozyme, secondary lethal changes might occur from damage to the cell's inner membrane as a result of osmotic forces in the presence of a defective cell wall. Hypertonic sucrose giving rise to plasmolysis and protection of the inner membrane was presumed to differentially inhibit the immune response mediated by lysozyme-free serum. The experimental results observed in this investigation have indicated, however, that the inhibitory effect of sucrose upon the bactericidal reaction may be explained simply by its anticomplementary effect and not by any effect on the bacterial cell. This view was supported by the following observations: (i) the comparability of the inhibitory effect of sucrose upon the immune hemolytic and bactericidal reactions, (ii) the comparable percentage loss in bactericidal activity of whole serum and lysozyme-free serum resulting from hypertonic sucrose, (iii) bactericidal antibody titrations were relatively unaffected and C titrations markedly inhibited by sucrose, (iv) the inhibitory effect of sucrose on the bactericidal reaction was unaffected by prior growth of the organism in the presence of sucrose, (v) the kinetics of the bactericidal reactivity of lysozyme-free serum in hypertonic sucrose, compared with whole serum, did not reveal a prolonged lag phase with lysozyme-free serum, but simply diminished reactivity at all times. These observations are compatible with the view that the C attack upon the outer surface of gram-negative bacteria, which plays a part in the cell's permeability control, may account for cell death. In this regard, the immune bactericidal reaction is quite comparable to the lysis of red cells or nucleated cells by C despite the lack of overt lysis in bacteria, probably because of their underlying supporting structures.

scholarly journals Cytotoxicity of Environmentally Relevant Concentrations of Aluminum in Murine Thymocytes and Lymphocytes

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Jamal Kamalov ◽  
David O. Carpenter ◽  
Irina Birman
Keyword(s):  
Flow Cytometry ◽  
Cell Death ◽  
Immune System ◽  
Dna Binding ◽  
Aluminum Chloride ◽  
Cell Swelling ◽  
Cytotoxic Effects ◽  
Minute Exposure ◽  
Low Concentrations ◽  
Dose Dependent

The effects of low concentrations of aluminum chloride on thymocytes and lymphocytes acutely dissociated from young mice were studied using flow cytometry with a DNA-binding dye. We demonstrate a rapid and dose-dependent injury in murine thymocytes and lymphocytes resulting from exposure to aluminum, as indicated by an increase in the entry into the cell of the DNA-binding dye, propidium iodine. A 60-minute exposure to 10 μM AlCl3caused damage of about 5% of thymocytes, while 50% were injured after 10 minutes at 20 μM. Nearly all thymocytes showed evidence of damage at 30 μM AlCl3after only 5 minutes of incubation. In lymphocytes, injury was observed at 15 μM AlCl3and less than 50% of cells were injured after a 60-minute exposure to 20 μM. Injury only rarely proceeded to rapid cell death and was associated with cell swelling. These results suggest that aluminum has cytotoxic effects on cells of the immune system.

scholarly journals Modulation of High-Voltage Activated Ca2+ Channels in the Rat Periaqueductal Gray Neurons by μ-Type Opioid Agonist

1997 ◽  
Vol 77 (3) ◽  
pp. 1418-1424 ◽  
Author(s):  
Chang-Ju Kim ◽  
Jeong-Seop Rhee ◽  
Norio Akaike
Keyword(s):  
G Proteins ◽  
Opioid Receptor ◽  
High Voltage ◽  
Inhibitory Effect ◽  
Periaqueductal Gray ◽  
Dependent Manner ◽  
Opioid Agonist ◽  
Voltage Clamp Condition ◽  
Voltage Dependent ◽  
Clamp Condition

Kim, Chang-Ju, Jeong-Seop Rhee, and Norio Akaike. Modulation of high-voltage activated Ca2+ channels in the rat periaqueductal gray neurons by μ-type opioid agonist. J. Neurophysiol. 77: 1418–1424, 1997. The effect of μ-type opioid receptor agonist, D-Ala2,N-MePhe4,Gly5-ol-enkephalin (DAMGO), on high-voltage-activated (HVA) Ca2+ channels in the dissociated rat periaqueductal gray (PAG) neurons was investigated by the use of nystatin-perforated patch recording mode under voltage-clamp condition. Among 118 PAG neurons tested, the HVA Ca2+ channels of 38 neurons (32%) were inhibited by DAMGO (DAMGO-sensitive cells), and the other 80 neurons (68%) were not affected by DAMGO (DAMGO-insensitive cells). The N-, P-, L-, Q-, and R-type Ca2+ channel components in DAMGO-insensitive cells shared 26.9, 37.1, 22.3, 7.9, and 5.8%, respectively, of the total Ca2+ channel current. The channel components of DAMGO-sensitive cells were 45.6, 25.7, 21.7, 4.6, and 2.4%, respectively. The HVA Ca2+ current of DAMGO-sensitive neurons was inhibited by DAMGO in a concentration-, time-, and voltage-dependent manner. Application of ω-conotoxin-GVIA occluded the inhibitory effect of DAMGO ∼70%. So, HVA Ca2+ channels inhibited by DAMGO were mainly the N-type Ca2+ channels. The inhibitory effect of DAMGO on HVA Ca2+ channels was prevented almost completely by the pretreatment of pertussis toxin (PTX) for 8–10 h, suggesting that DAMGO modulation on N-type Ca2+ channels in rat PAG neurons is mediated by PTX-sensitive G proteins. These results indicate that μ-type opioid receptor modulates N-type HVA Ca2+ channels via PTX-sensitive G proteins in PAG neurons of rats.

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