The modulation of necroptosis and its therapeutic potentials

Kim Chun 대한독성 유전단백체 학회 2021 Molecular & cellular toxicology Vol.17 No.2

Purpose of review Necroptosis is a form of cell death regulated by specific cellular protein machinery. Although the cell death is tightly controlled like apoptosis, another type of programed cell death, the biological features of necroptosis rather resemble necrosis that is defined as an uncontrolled accidental cell death. The pathway executing necroptosis relies on a protein kinase, RIPK3, and its downstream effector molecule, MLKL. Upon necroptosis initiating signals, both RIPK3 and MLKL undergo extensive post-translation modifications to construct a death complex called necrosome, finally leading to lysis of cell membrane. Preclinical mouse models demonstrated the physiological importance of necroptosis in the progress of various inflammation-associated diseases. The objective of this brief review is to introduce a new emerging concept in cell death biology and to provide a first entry into the research field of necroptosis. Recent findings The uncovering of necroptosis pathway brought a fundamental change in the basic concept that necrotic cell death is passive and unregulated. Currently, multiple small molecules that can target necrotic cell death are under development and some of them are under clinical trials to evaluate their therapeutic potentials. Better understanding of the molecular mechanism leveraging necroptosis will provide an unprecedented opportunity to pathological necrosis-driven human diseases. Purpose of review Necroptosis is a form of cell death regulated by specific cellular protein machinery. Although the cell death is tightly controlled like apoptosis, another type of programed cell death, the biological features of necroptosis rather resemble necrosis that is defined as an uncontrolled accidental cell death. The pathway executing necroptosis relies on a protein kinase, RIPK3, and its downstream effector molecule, MLKL. Upon necroptosis initiating signals, both RIPK3 and MLKL undergo extensive post-translation modifications to construct a death complex called necrosome, finally leading to lysis of cell membrane. Preclinical mouse models demonstrated the physiological importance of necroptosis in the progress of various inflammation-associated diseases. The objective of this brief review is to introduce a new emerging concept in cell death biology and to provide a first entry into the research field of necroptosis. Recent findings The uncovering of necroptosis pathway brought a fundamental change in the basic concept that necrotic cell death is passive and unregulated. Currently, multiple small molecules that can target necrotic cell death are under development and some of them are under clinical trials to evaluate their therapeutic potentials. Better understanding of the molecular mechanism leveraging necroptosis will provide an unprecedented opportunity to pathological necrosis-driven human diseases.

MicroRNA expression profiling of adult hippocampal neural stem cells upon cell death reveals an autophagic cell death-like pattern

Park, Sujeong,Lee, Steven Hyun Seung,Lee, Won Il,Choi, Rachelle,Kim, Seong Who,Woo, Ha-Na,Lee, Heuiran Elsevier 2019 Biochemical and biophysical research communication Vol.509 No.3

<P><B>Abstract</B></P> <P>Adult hippocampal neural (HCN) stem cells promptly undergo irreversible autophagic cell death (ACD) if deprived of insulin in culture. Small, non-coding microRNAs (miRNA) play an important role in regulating biological processes, including proliferation and cell death. However, there have been no reports thus far regarding miRNA involvement in the induction of adult HCN stem cell death under insulin-deprived conditions, for which we performed a microarray-based analysis to examine the expression signature of miRNAs in adult rat HCN stem cells. Three independent specimens per culture condition either with or without insulin were prepared and a miRNA microarray analysis carried out. A total of 12 exhibited significantly altered expression levels upon cell death due to the absence of insulin when compared to HCN stem cells cultured with insulin present (cut-off limit; p < 0.05 and fold-change >1.3) The resulting volcano plot showed that, among these miRNAs, seven were upregulated and five were downregulated. The upregulated miRNAs were capable of modulating HCN stem cell death. Caspase-3 activity analysis, LC3 conversion, and TEM of autophagosome formation consistently suggested that ACD, not apoptosis, was most likely the mechanism affecting HCN cell death. As such, we have come to term these miRNAs, “HCN stem cell-specific autophagic cell death regulators.” Taken together, our data suggest that the miRNA expression profile of HCN stem cells is altered during ACD occurring due to insulin deprivation and that differentially expressed miRNAs are involved in HCN stem cell viability. Detailed explorations of the underlying mechanisms regarding HCN stem cell viability modulation by these miRNAs would be beneficial in further understanding the physiological features of adult HCN stem cells and are currently being investigated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Insulin deprivation leads to autophagic cell death of hippocampal neural (HCN) stem cells. </LI> <LI> Expression pattern analysis of autophagic HCN stem death shows 7 upregulated microRNAs. </LI> <LI> Upregulated microRNAs induce autophagic HCN stem cell death under normal conditions. </LI> <LI> They have been termed, “HCN stem cell-specific autophagic cell death regulators”. </LI> </UL> </P>

Functional roles of the pepper leucine-rich repeat protein and its interactions with pathogenesis-related and hypersensitive-induced proteins in plant cell death and immunity

Hong, Jeum Kyu,Hwang, In Sun,Hwang, Byung Kook Springer-Verlag 2017 Planta Vol.246 No.3

<P> Main conclusion Pepper leucine-rich repeat protein (CaLRR1) interacts with defense response proteins to regulate plant cell death and immunity. This review highlights the current understanding of the molecular functions of CaLRR1 and its interactor proteins. Plant cell death and immune responses to microbial pathogens are controlled by complex and tightly regulated molecular signaling networks. Xanthomonas campestris pv. vesicatoria (Xcv)-inducible pepper (Capsicum annuum) leucine-rich repeat protein 1 (CaLRR1) serves as a molecular marker for plant cell death and immunity signaling. In this review, we discuss recent advances in elucidating the functional roles of CaLRR1 and its interacting plant proteins, and understanding how they are involved in the cell death and defense responses. CaLRR1 physically interacts with pepper pathogenesis-related proteins (CaPR10 and CaPR4b) and hypersensitive-induced reaction protein (CaHIR1) to regulate plant cell death and defense responses. CaLRR1 is produced in the cytoplasm and trafficked to the extracellular matrix. CaLRR1 binds to CaPR10 in the cytoplasm and CaPR4b and CaHIR1 at the plasma membrane. CaLRR1 synergistically accelerates CaPR10-triggered hypersensitive cell death, but negatively regulates CaPR4b- and CaHIR1-triggered cell death. CaHIR1 interacts with Xcv filamentous hemagglutinin (Fha1) to trigger disease-associated cell death. The subcellular localization and cellular function of these CaLRR1 interactors during plant cell death and defense responses were elucidated by Agrobacterium-mediated transient expression, virus-induced gene silencing, and transgenic overexpression studies. CaPR10, CaPR4b, and CaHIR1 positively regulate defense signaling mediated by salicylic acid and reactive oxygen species, thereby activating hypersensitive cell death and disease resistance. A comprehensive understanding of the molecular functions of CaLRR1 and its interacting protein partners in cell death and defense responses will provide valuable information for the molecular genetics of plant disease resistance, which could be exploited as a sustainable disease management strategy. </P>

MG132, a proteasome inhibitor, induces human pulmonary fibroblast cell death via increasing ROS levels and GSH depletion

PARK, WOO HYUN,KIM, SUHN HEE D.A. Spandidos 2012 Oncology reports Vol.27 No.4

<P>MG132 as a proteasome inhibitor can induce apoptotic cell death in lung cancer cells. However, little is known about the toxicological cellular effects of MG132 on normal primary lung cells. Here, we investigated the effects of N-acetyl cysteine (NAC) and vitamin C (well known antioxidants) or L-buthionine sulfoximine (BSO; an inhibitor of GSH synthesis) on MG132-treated human pulmonary fibroblast (HPF) cells in relation to cell death, reactive oxygen species (ROS) and glutathione (GSH). MG132 induced growth inhibition and death in HPF cells, accompanied by the loss of mitochondrial membrane potential (MMP; ΔΨ<SUB>m</SUB>). MG132 increased ROS levels and GSH-depleted cell numbers in HPF cells. Both antioxidants, NAC and vitamin C, prevented growth inhibition, death and MMP (ΔΨ<SUB>m</SUB>) loss in MG132-treated HPF cells and also attenuated ROS levels in these cells. BSO showed a strong increase in ROS levels in MG132-treated HPF cells and slightly enhanced the growth inhibition, cell death, MMP (ΔΨ<SUB>m</SUB>) loss and GSH depletion. In addition, NAC decreased anonymous ubiquitinated protein levels in MG132-treated HPF cells. Furthermore, superoxide dismutase (SOD) 2, catalase (CTX) and GSH peroxidase (GPX) siRNAs enhanced HPF cell death by MG132, which was not correlated with ROS and GSH level changes. In conclusion, MG132 induced the growth inhibition and death of HPF cells, which were accompanied by increasing ROS levels and GSH depletion. Both NAC and vitamin C attenuated HPF cell death by MG132, whereas BSO slightly enhanced the death.</P>

Dual Effect of Nerve Growth Factor on Cell Death of PC12 Cells Induced by Serum Deprivation

KyuChung Hur,Mijung Kwon,Sooryun Seo,Hoyoung Chun,Jun-Mo Chung,In Kwon Chung 한국분자세포생물학회 2002 Molecules and cells Vol.13 No.2

The effect of nerve growth factor (NGF) on the cell death of PC12 cells that is induced by serum deprivation was examined in the floating and attached cells to the extracellular matrix. NGF suppressed cell death occurred in the floating cells. The onset of cell death in the attached cells was much slower than in the floating cells. Moreover, the cell death in the attached cells was either accelerated in a high-density culture (over ~50% confluent), or inhibited in a low-density culture by NGF. While nucleosomal DNA fragmentation and poly (ADP-ribose) polymerase degradation was observed in both the floating and attached cells, the incidence of nuclear fragmentation and chromatin condensation was much lower in the attached cells than in the floating cells. The delayed onset of cell death in the attached cells was due to the signals that are generated from the extracellular matrix that is formed by PC12 cells, together with cell-to-cell interaction. The acceleration of cell death in the NGF-treated cells was anoikis, caused by the loss of the anchorage of the cell via the action of increased activities of matrix metalloproteinases (MMP2, MMP9). These results suggest that NGF has a different role in the cell death of PC12 cells that is induced by serum deprivation, depending on the cell-matrix, as well as the cell-cell interaction.

Chracterization of THP-1 Cell Death Induced by Porphyromonas gingivalis Infection

송유리,김세연,박미희,나희삼,정진 대한구강생물학회 2017 International Journal of Oral Biology Vol.42 No.1

Background: Periodontitis is generally a chronic disorder characterized by the breakdown of tooth-supporting tissues. P. gingivalis, a Gram-negative anaerobic rod, is one of the major pathogens associated with periodontitis. Frequently, P. gingivalis infection leads to cell death. However, the correlation between P. gingivalis–induced cell death and periodontal inflammation remains to be elucidated. Among cell deaths, the death of immune cells appears to play a significant role in inflammatory response. Thus, the aim of this study was to examine P. gingivalis–induced cell death, focusing on autophagy and apoptosis in THP-1 cells. Methods: Human acute monocytic leukemia cell line (THP-1) was used for all experiments. Autophagy induced by P. gingivalis in THP-1 cells was examined by Cyto ID staining. Intracellular autophagic vacuoles were observed by fluorescence microscopy using staining Acridine orange (AO); and 3-methyladenine (3-MA) was used to inhibit autophagy. Total cell death was measured by LDH assay. Cytokine production was measured by an ELISA method. Results: P. gingivalis induced autophagy in an MOI-dependent manner in THP-1 cells, but 3-MA treatment decreased autophagy and increased the apoptotic blebs. P. gingivalis infection did not increase apoptosis compared to the control cells, whereas inhibition of autophagy by 3-MA significantly increased apoptosis in P. gingivalis-infected THP-1 cells. Inhibition of autophagy by 3-MA also increased total cell deaths and inflammatory cytokine production, including IL-1β and TNF-⍺. Conclusion: P. gingivalis induced autophagy in THP-1 cells, but the inhibition of autophagy by 3-MA stimulated apoptosis, leading to increased cell deaths and pro-inflammatory cytokines production. Hence, the modulation of cell deaths may provide a mechanism to fight against invading microorganisms in host cells and could be a promising way to control inflammation.

Roles of NF-κB and Bcl-2 in Two Differential Modes of Cell Death of Mouse Cortical Collecting Duct Cells

Song, J.M.,Lee, R.H.,Jung, J.S. S. Karger AG 2005 Kidney & blood pressure research Vol.28 No.2

<P>Recent data have implicated nuclear factor-κB (NF-κB) and Bcl-2 in the regulation of apoptotic and necrotic cell death in various cells. However, mechanisms of their effects on cell death of renal epithelial cells are not clear. First, we investigated the effect of specific inhibition of NF-κB and overexpression of Bcl-2 on necrotic cell death induced by hydrogen peroxide or cisplatin in renal collecting duct cells. M-1 cells, which were derived from outer cortical collecting duct, were stably transfected with the non-phosphorylatable mutant of inhibitory-κBα (I-κBα) and Bcl-2. Overexpression of I-κBα and Bcl-2 did not affect cisplatin-induced necrotic cell death, but overexpression of I-κBα significantly decreased H<SUB>2</SUB>O<SUB>2</SUB>-induced cell death. Regarding apoptotic cell death induced by cisplatin, serum deprivation and contact inhibition was increased by overexpression of I-κBα, whereas overexpression of <I>bcl-2</I> inhibited the apoptotic cell death. I-κBα overexpression increased Bax expression and decreased cIAP-1 and -2 expression compared to vector-transfected cells, but did not alter SAPK/JNK activity in the presence or absence of cisplatin. NF-κB activity was significantly higher in <I>bcl-2-</I>overexpressing cells than in control cells. These data show that activation of NF-κB mediates H<SUB>2</SUB>O<SUB>2</SUB>-induced necrotic injury, but inhibits apoptotic cell death in renal collecting duct cells, and that Bcl-2 selectively protects apoptotic cell death in M-1 cells.</P><P>Copyright © 2005 S. Karger AG, Basel</P>

Effects of Cell Cycle Inhibitors on Cell Death of Human Cancer Cell Lines

Whang, Kyung-Tae,Kim, Myung-Soo,Kim, Gwan-Shik The Official Publication of Korean Academy of Oral 1995 International Journal of Oral Biology Vol.19 No.1

Genotoxic agents are known to cause cell death mostly by apoptosis in susceptible cells and this action plays an important role in tumor regression after chemotherapy. It has been thought that the apoptotic process may be associated with cell cycle. In the present study, the effect of aphidicolin and nocodazole, reversible cell cycle inhibitors, on the apoptosis or cell death induced by actinomycin D was studied in 3 cell lines. HeLa, SiHa and NIH/3T3 cells were treated with actinomycin D(100 nM)alone or in combination with cell cycle inhibitors for 20 hours; or presynchronized cells were treated with actinomycin D for 4 hours and further incubated for 20 hours in fresh medium. The synergistic effect of IBMX(5 or 10 μM)on the apoptosis or cell death induced by actinomycin D was also studied. The results were as follows; Majority of HeLa cells showed apoptotic changes after actinomycin D treatment. Aphidicolin or nocodazole blocked neither initiation nor progression of actinomycin D-induced apoptosis in HeLa cell. Aphidicolin pretreatment enhanced the actinomycin D-induced apoptosis of HeLa cells and cell death of SiHa cells and nocodazole pretreatment enhanced cell death of SiHa cells. IBMX moderately enhanced actinomycin D-induced cell death of NIH/3T3 and to less extent that of SiHa cells. These results show that neither initiation nor progression of actinomycin D-induced apoptosis or cell death can be blocked by cell cycle arrest, and that cAMP is partly responsible for actinomycin D-induced apoptosis in certain types of cells.

The RNase Activity of Rice Probenazole-Induced Protein1 (PBZ1) Plays a Key Role in Cell Death in Plants

김상곤,김선태,Yiming Wang,Seok Yu,최인수,김용철,김우택,Ganesh Kumar Agrawal,Randeep Rakwal,강규영 한국분자세포생물학회 2011 Molecules and cells Vol.31 No.1

Cell death is an important process of plant responses to development and biotic/abiotic stresses. In rice plants, PBZ1, a PR10 family protein, has been shown to accumu-late in tissues undergoing cell death. However, the func-tion of PBZ1 in cell death remains yet to be demonstrated. Here, we report that exogenous recombinant PBZ1 protein induces cell death in rice suspension-cultured cells (SCCs) and also in leaves of Nicotiana tabacum in a dose-dependent manner. This finding was confirmed in vivo in transgenic Arabidopsis lines harboring the PBZ1 gene under the control of a dexamethasone (DEX)-inducible promoter. The DEX-treated leaves of transgenic Arabidopsis induced expression of PBZ1 at transcript and protein levels and showed cell death morphology. TUNEL analysis detected DNA fragmentation, a hallmark of programmed cell death, in rice SCCs treated with the PBZ1 protein. Recombinant PBZ1 protein also exhibited RNase activity and exhibited internalization inside BY-2 cells. Taken together, PBZ1 induces cell death not only in rice, but also in tobacco and Arabidopsis via its RNase activity inside the cell. PBZ1 could be used as a marker to understand the me-chanism by which PBZ1 confers the cell death morpholo-gy in rice and other model plants.

Protective Role of Tissue Transglutaminase in the Cell Death Induced by TNF-α in SH-SY5Y Neuroblastoma Cells

( Soo Mi Kweon ),( Zee Won Lee ),( Sun Ju Yi ),( Young Myeong Kim ),( Jeong A Han ),( Sang Gi Paik ),( Kwon Soo Ha ) 생화학분자생물학회 2004 BMB Reports Vol.37 No.2

Tissue transglutaminase (tTGase) regulates various biological processes, including extracellular matrix organization, cellular differentiation, and apoptosis. Here we report the protective role of tTGase in the cell death that is induced by the tumor necrosis factor a(TNF-α) and ceramide, a product of the TNF-αsignaling pathway, in human neuroblastoma SH-SY5Y cells. Treatment with retinoic acid (RA) induced the differentiation of the neuroblastoma cells with the formation of extended neurites. Immunostaining and Western blot analysis tTGase expression by RA treatment. TNF-αor C, ceramide, a cell permeable ceramide analog, induced cell death in normal cells, but cell death was largely inhibited by the RA treatment. The inhibition of tTGase by the tTGase inhibitors, mono-dansylcadaverline and cystamine, eliminated the protective role of RA-treatment in the cell death that is caused by TNF-α or C_(2)-ceramide, In addition, the co-treatment of TNF-α and cycloheximide decreased the protein level of tTGase and cell viability in the RA-treated cells, supporting the role of tTGase in the protection of cell death. DNA fragmentation was also induced by the co-treatment of TNF-α and cycloheximide. These results suggest that tTGase expressed by RA treatment plays an important role in the protection of cell death caused by TNF-α and ceramide.