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The Journal of Experimental Medicine Mar 2021Podocyte injury is a common hallmark in various glomerular diseases. The level of LRRC55 was increased in podocytes of patients with focal segmental glomerulosclerosis...
Podocyte injury is a common hallmark in various glomerular diseases. The level of LRRC55 was increased in podocytes of patients with focal segmental glomerulosclerosis (FSGS), diabetic nephropathy (DN), and membranous nephropathy (MN). Upregulated LRRC55 and increased intracellular Ca2+ led to BK channel activation and the loss of intracellular potassium, resulting in apoptosome formation and caspase-3 activation in angiotensin II (Ang II)-treated podocytes. Knockout of Lrrc55 or the BK channel prevented the BK current and ameliorated podocyte injury in Ang II-treated mice. Upstream, NFATc3 regulated the expression of LRRC55. Increased LRRC55 expression in podocytes was also evident in animal models of FSGS, DN, and MN. Treatment with losartan or LRRC55 siRNA suppressed LRRC55 expression, prevented BK channel activation, and attenuated podocyte injury in animal models of FSGS, DN, and MN. In conclusion, upregulated LRRC55 promotes BK channel activation and aggravates cell injury in podocytes in FSGS, DN, and MN. LRRC55 inhibition may represent a new therapeutic approach for podocyte injury.
Topics: Angiotensin II; Animals; Apoptosis; Calcium; Cell Nucleus; Humans; Intracellular Space; Ion Channel Gating; Kidney Glomerulus; Large-Conductance Calcium-Activated Potassium Channels; Losartan; Membrane Proteins; Mice, Inbred C57BL; Mice, Knockout; Models, Biological; NFATC Transcription Factors; Podocytes; Potassium; Promoter Regions, Genetic; Protein Transport; TRPC6 Cation Channel; Up-Regulation; Mice
PubMed: 33346797
DOI: 10.1084/jem.20192373 -
Mitochondrion Jul 2016Genistein (4',5,7-trihydroxyisoflavone; C15H10O5), an isoflavone, has been investigated as an anti-cancer agent due to its ability to trigger cell death (both intrinsic... (Review)
Review
Genistein (4',5,7-trihydroxyisoflavone; C15H10O5), an isoflavone, has been investigated as an anti-cancer agent due to its ability to trigger cell death (both intrinsic and extrinsic apoptotic pathways) in different cancer cells in vitro and in vivo. Furthermore, genistein has been viewed as a mitochondriotropic molecule due to the direct effects this isoflavone induces in mitochondria, such as modulation of enzymatic activity of components of the oxidative phosphorylation system. Apoptosis triggering may also be mediated by genistein through activation of the mitochondria-dependent pathway by a mechanism associated with mitochondrial dysfunction (i.e., disruption of the mitochondrial membrane potential - MMP, release of cytochrome c, activation of the apoptosome, among others). Efforts have been made in order to elucidate how genistein coordinate these biochemical phenomena. Nonetheless, some areas of the mitochondria-associated research (mitochondrial biogenesis, redox biology of mitochondria, and mitochondria-associated bioenergetic parameters) need to be explored regarding the role of genistein as a mitochondria-targeted agent. This is a pharmacologically relevant issue due to the possibility of using genistein as a mitochondria-targeted drug in cases of cancer, neurodegeneration, cardiovascular, and endocrine disease, for example. The present review aims to describe, compare, and discuss relevant data about the effects of genistein upon mitochondria.
Topics: Animals; Anticarcinogenic Agents; Apoptosis; Genistein; Humans; Mitochondria
PubMed: 27223841
DOI: 10.1016/j.mito.2016.05.005 -
The Journal of Biological Chemistry Sep 2014The protease caspase-9 is activated on the apoptosome, a multiprotein signal transduction platform that assembles in response to mitochondria-dependent apoptosis...
The protease caspase-9 is activated on the apoptosome, a multiprotein signal transduction platform that assembles in response to mitochondria-dependent apoptosis initiation. Despite extensive molecular research, the assembly of the holo-apoptosome and the process of caspase-9 activation remain incompletely understood. Here, we therefore integrated quantitative data on the molecular interactions and proteolytic processes during apoptosome formation and apoptosis execution and conducted mathematical simulations to investigate the resulting biochemical signaling, quantitatively and kinetically. Interestingly, when implementing the homodimerization of procaspase-9 as a prerequisite for activation, the calculated kinetics of apoptosis execution and the efficacy of caspase-3 activation failed to replicate experimental data. In contrast, assuming a scenario in which procaspase-9 is activated allosterically upon binding to the apoptosome backbone, the mathematical simulations quantitatively and kinetically reproduced all experimental data. These data included a XIAP threshold concentration at which apoptosis execution is suppressed in HeLa cervical cancer cells, half-times of procaspase-9 processing, as well as the molecular timer function of the apoptosome. Our study therefore provides novel mechanistic insight into apoptosome-dependent apoptosis execution and suggests that caspase-9 is activated allosterically by binding to the apoptosome backbone. Our findings challenge the currently prevailing dogma that all initiator procaspases require homodimerization for activation.
Topics: Allosteric Regulation; Apoptosis; Apoptosomes; Apoptotic Protease-Activating Factor 1; Caspase 9; Catalytic Domain; Computer Simulation; Enzyme Activation; HeLa Cells; Humans; Kinetics; Models, Molecular; Protein Binding; Protein Multimerization; Protein Precursors; Systems Biology
PubMed: 25107908
DOI: 10.1074/jbc.M114.590034 -
Archives of Biochemistry and Biophysics Mar 2018Apaf-1 is a cytosolic multi-domain protein in the apoptosis regulatory network. When cytochrome c releases from mitochondria; it binds to WD-40 repeats of Apaf-1...
Apaf-1 is a cytosolic multi-domain protein in the apoptosis regulatory network. When cytochrome c releases from mitochondria; it binds to WD-40 repeats of Apaf-1 molecule and induces oligomerization of Apaf-1. Here in, a split luciferase assay was used to compare apoptosome formation in cell-free and cell-based systems. This assay uses Apaf-1 tagged with either N-terminal fragment or C-terminal fragment of P. pyralis luciferase. In cell based-system, the apoptosome formation is induced inside the cells which express Apaf-1 tagged with complementary fragments of luciferase while in cell-free system, the apoptosome formation is induced in extracts of the cells. In cell-free system, cytochrome c dependent luciferase activity was observed with full length Apaf-1. However, luciferase activity due to apoptosome formation was much higher in cell based system compared to cell-free system. The truncated Apaf-1 which lacks WD-40 repeats (ΔApaf-1) interacted with endogenous Apaf-1 in a different fashion compared to native form as confirmed by different retention time of eluate in gel filtration and binding to affinity column. The interactions between endogenous Apaf-1 and ΔApaf-1 is stronger than its interaction with native exogenous Apaf-1 as indicated by dominant negative effect of ΔApaf-1 on caspase-3 processing.
Topics: Apoptosis; Apoptosomes; Apoptotic Protease-Activating Factor 1; Biopolymers; Caspase 3; Caspase 9; Cell-Free System; Chromatography, Affinity; Chromatography, Gel; Enzyme Activation; HEK293 Cells; Humans; Luciferases; Protein Binding; Proteolysis; WD40 Repeats
PubMed: 29410086
DOI: 10.1016/j.abb.2018.01.017 -
Structure (London, England : 1993) Apr 2017While earlier studies of Apaf-1 holo-apoptosome architecture revealed the spectacular heptameric wheel-like structure formed by Apaf-1, the central CARD disk responsible...
While earlier studies of Apaf-1 holo-apoptosome architecture revealed the spectacular heptameric wheel-like structure formed by Apaf-1, the central CARD disk responsible for caspase-9 recruitment remained incompletely resolved. In a recent issue of Structure, Su et al. (2017) describe a crystal structure of the complex between Apaf-1 CARD and caspase-9 CARD. Together with two recent cryo-EM structures, this work brings us closer to a full view of the holo-apoptosome.
Topics: Apoptosis; Apoptosomes; Apoptotic Protease-Activating Factor 1; Caspase 9
PubMed: 28380338
DOI: 10.1016/j.str.2017.03.013 -
Cell Death & Disease May 2020Caspase-2, -9, and -3 are reported to control myoblast differentiation into myotubes. This had been previously explained by phosphatidylserine exposure on apoptotic...
Caspase-2, -9, and -3 are reported to control myoblast differentiation into myotubes. This had been previously explained by phosphatidylserine exposure on apoptotic myoblasts inducing differentiation in neighboring cells. Here we show for the first time that caspase-3 is activated in the myoblasts undergoing differentiation. Using RNAi, we also demonstrate that differentiation requires both cytochrome c and Apaf-1, and by using a new pharmacological approach, we show that apoptosome formation is required. We also show that Bid, whose cleavage links caspase-2 to the mitochondrial death pathway, was required for differentiation, and that the caspase cleavage product, tBid, was generated during differentiation. Taken together, these data suggest that myoblast differentiation requires caspase-2 activation of the mitochondrial death pathway, and that this occurs in the cells that differentiate. Our data also reveal a hierarchy of caspases in differentiation with caspase-2 upstream of apoptosome activation, and exerting a more profound control of differentiation, while caspases downstream of the apoptosome primarily control cell fusion.
Topics: Animals; Apoptosis; Apoptosomes; Apoptotic Protease-Activating Factor 1; BH3 Interacting Domain Death Agonist Protein; Caspase 2; Caspase 3; Caspase Inhibitors; Cell Differentiation; Cell Fusion; Cell Line; Cyclohexanones; Cytochromes c; Enzyme Activation; Gene Knockdown Techniques; Humans; Mice; Muscle Fibers, Skeletal; Myoblasts; RNA, Small Interfering
PubMed: 32366831
DOI: 10.1038/s41419-020-2502-4 -
Frontiers in Immunology 2024Carotid atherosclerosis (CAS) is a complication of atherosclerosis (AS). PAN-optosome is an inflammatory programmed cell death pathway event regulated by the...
BACKGROUND
Carotid atherosclerosis (CAS) is a complication of atherosclerosis (AS). PAN-optosome is an inflammatory programmed cell death pathway event regulated by the PAN-optosome complex. CAS's PAN-optosome-related genes (PORGs) have yet to be studied. Hence, screening the PAN-optosome-related diagnostic genes for treating CAS was vital.
METHODS
We introduced transcriptome data to screen out differentially expressed genes (DEGs) in CAS. Subsequently, WGCNA analysis was utilized to mine module genes about PANoptosis score. We performed differential expression analysis (CAS samples standard samples) to obtain CAS-related differentially expressed genes at the single-cell level. Venn diagram was executed to identify PAN-optosome-related differential genes (POR-DEGs) associated with CAS. Further, LASSO regression and RF algorithm were implemented to were executed to build a diagnostic model. We additionally performed immune infiltration and gene set enrichment analysis (GSEA) based on diagnostic genes. We verified the accuracy of the model genes by single-cell nuclear sequencing and RT-qPCR validation of clinical samples, as well as cellular experiments.
RESULTS
We identified 785 DEGs associated with CAS. Then, 4296 module genes about PANoptosis score were obtained. We obtained the 7365 and 1631 CAS-related DEGs at the single-cell level, respectively. 67 POR-DEGs were retained Venn diagram. Subsequently, 4 PAN-optosome-related diagnostic genes (, , , and ) were identified via machine learning. Cellular function tests on four genes showed that these genes have essential roles in maintaining arterial cell viability and resisting cellular senescence.
CONCLUSION
We obtained four PANoptosis-related diagnostic genes (, , , and ) associated with CAS, laying a theoretical foundation for treating CAS.
Topics: Humans; Single-Cell Analysis; Atherosclerosis; Apoptosis; Gene Expression Profiling; Transcriptome; Gene Regulatory Networks; Male; Female
PubMed: 38736872
DOI: 10.3389/fimmu.2024.1297298 -
Cancers Sep 2023Acetylcholinesterase is a well-known protein because of the relevance of its enzymatic activity in the hydrolysis of acetylcholine in nerve transmission. In addition to... (Review)
Review
Acetylcholinesterase is a well-known protein because of the relevance of its enzymatic activity in the hydrolysis of acetylcholine in nerve transmission. In addition to the catalytic action, it exerts non-catalytic functions; one is associated with apoptosis, in which acetylcholinesterase could significantly impact the survival and aggressiveness observed in cancer. The participation of AChE as part of the apoptosome could explain the role in tumors, since a lower AChE content would increase cell survival due to poor apoptosome assembly. Likewise, the high Ach content caused by the reduction in enzymatic activity could induce cell survival mediated by the overactivation of acetylcholine receptors (AChR) that activate anti-apoptotic pathways. On the other hand, in tumors in which high enzymatic activity has been observed, AChE could be playing a different role in the aggressiveness of cancer; in this review, we propose that AChE could have a pro-inflammatory role, since the high enzyme content would cause a decrease in ACh, which has also been shown to have anti-inflammatory properties, as discussed in this review. In this review, we analyze the changes that the enzyme could display in different tumors and consider the different levels of regulation that the acetylcholinesterase undergoes in the control of epigenetic changes in the mRNA expression and changes in the enzymatic activity and its molecular forms. We focused on explaining the relationship between acetylcholinesterase expression and its activity in the biology of various tumors. We present up-to-date knowledge regarding this fascinating enzyme that is positioned as a remarkable target for cancer treatment.
PubMed: 37760598
DOI: 10.3390/cancers15184629 -
Journal of Molecular Biology Sep 2019SARM1 induces axonal degeneration in response to various insults and is therefore considered an attractive drug target for the treatment of neuro-degenerative diseases...
SARM1 induces axonal degeneration in response to various insults and is therefore considered an attractive drug target for the treatment of neuro-degenerative diseases as well as for brain and spinal cord injuries. SARM1 activity depends on the integrity of the protein's SAM domains, as well as on the enzymatic conversion of NAD+ to ADPR (ADP Ribose) products by the SARM1's TIR domain. Therefore, inhibition of either SAM or TIR functions may constitute an effective therapeutic strategy. However, there is currently no SARM1-directed therapeutic approach available because of an insufficient structural and mechanistic understanding of this protein. In this study, we found that SARM1 assembles into an octameric ring. This arrangement was not described before in other SAM proteins, but is reminiscent of the apoptosome and inflammasome-well-known apoptotic ring-like oligomers. We show that both SARM1 and the isolated tandem SAM domains form octamers in solution, and electron microscopy analysis reveals an octameric ring of SARM1. We determined the crystal structure of SAM and found that it also forms a closed octameric ring in the crystal lattice. The SAM ring interactions are mediated by complementing "lock and key" hydrophobic grooves and inserts and electrostatic charges between the neighboring protomers. We have mutated several interacting SAM interfaces and measured how these mutations affect SARM1 apoptotic activity in cultured cells, and in this way identified critical oligomerization sites that facilitate cell death. These results highlight the importance of oligomerization for SARM1 function and reveal critical epitopes for future targeted drug development.
Topics: Amino Acid Sequence; Armadillo Domain Proteins; Crystallography, X-Ray; Cytoskeletal Proteins; Humans; Models, Molecular; Protein Domains; Protein Multimerization; Solutions
PubMed: 31278906
DOI: 10.1016/j.jmb.2019.06.030 -
Molecular & Cellular Oncology 2017For nearly 2 decades, investigators have debated whether cysteinyl-aspartate-specific protease 9 (caspase-9) is activated within the apoptotic protease-activating factor...
For nearly 2 decades, investigators have debated whether cysteinyl-aspartate-specific protease 9 (caspase-9) is activated within the apoptotic protease-activating factor 1 (Apaf-1) apoptosome through proximity-induced homodimerization or through formation of a holoenzyme. Recently, we have demonstrated that caspase-9 forms (and likely transitions between) both caspase-9 homo- and Apaf-1:caspase-9 heterodimers, each of which plays unique roles in the recruitment and activation of caspase-9.
PubMed: 28401186
DOI: 10.1080/23723556.2017.1281865