scholarly journals Apoptotic Cells Trigger Calcium Entry in Phagocytes by Inducing the Orai1-STIM1 Association

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2702
Author(s):  
Deokhwan Kim ◽  
Hyunji Moon ◽  
Hyeokjin Cho ◽  
Chanhyuk Min ◽  
Byeongjin Moon ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Phospholipase C ◽  
Molecular Mechanism ◽  
Calcium Level ◽  
Calcium Release ◽  
Apoptotic Cell ◽  
Calcium Entry ◽  
Calcium Flux ◽  
Apoptotic Cells ◽  
Store Operated Calcium Entry

Swift and continuous phagocytosis of apoptotic cells can be achieved by modulation of calcium flux in phagocytes. However, the molecular mechanism by which apoptotic cells modulate calcium flux in phagocytes is incompletely understood. Here, using biophysical, biochemical, pharmaceutical, and genetic approaches, we show that apoptotic cells induced the Orai1-STIM1 interaction, leading to store-operated calcium entry (SOCE) in phagocytes through the Mertk-phospholipase C (PLC) γ1-inositol 1,4,5-triphosphate receptor (IP3R) axis. Apoptotic cells induced calcium release from the endoplasmic reticulum, which led to the Orai1-STIM1 association and, consequently, SOCE in phagocytes. This association was attenuated by masking phosphatidylserine. In addition, the depletion of Mertk, which indirectly senses phosphatidylserine on apoptotic cells, reduced the phosphorylation levels of PLCγ1 and IP3R, resulting in attenuation of the Orai1-STIM1 interaction and inefficient SOCE upon apoptotic cell stimulation. Taken together, our observations uncover the mechanism of how phagocytes engulfing apoptotic cells elevate the calcium level.

scholarly journals Synthesis and Pharmacological Characterization of 2-Aminoethyl Diphenylborinate (2-APB) Derivatives for Inhibition of Store-Operated Calcium Entry (SOCE) in MDA-MB-231 Breast Cancer Cells

2020 ◽  
Vol 21 (16) ◽  
pp. 5604 ◽  
Author(s):  
Achille Schild ◽  
Rajesh Bhardwaj ◽  
Nicolas Wenger ◽  
Dominic Tscherrig ◽  
Palanivel Kandasamy ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Endoplasmic Reticulum ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Structural Changes ◽  
Calcium Entry ◽  
Imaging Plate ◽  
Ip3 Receptors ◽  
Pharmacological Characterization ◽  
Store Operated Calcium Entry

Calcium ions regulate a wide array of physiological functions including cell differentiation, proliferation, muscle contraction, neurotransmission, and fertilization. The endoplasmic reticulum (ER) is the major intracellular Ca2+ store and cellular events that induce ER store depletion (e.g., activation of inositol 1,4,5-triphosphate (IP3) receptors) trigger a refilling process known as store-operated calcium entry (SOCE). It requires the intricate interaction between the Ca2+ sensing stromal interaction molecules (STIM) located in the ER membrane and the channel forming Orai proteins in the plasma membrane (PM). The resulting active STIM/Orai complexes form highly selective Ca2+ channels that facilitate a measurable Ca2+ influx into the cytosol followed by successive refilling of the ER by the sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA). STIM and Orai have attracted significant therapeutic interest, as enhanced SOCE has been associated with several cancers, and mutations in STIM and Orai have been linked to immunodeficiency, autoimmune, and muscular diseases. 2-Aminoethyl diphenylborinate (2-APB) is a known modulator and depending on its concentration can inhibit or enhance SOCE. We have synthesized several novel derivatives of 2-APB, introducing halogen and other small substituents systematically on each position of one of the phenyl rings. Using a fluorometric imaging plate reader (FLIPR) Tetra-based calcium imaging assay we have studied how these structural changes of 2-APB affect the SOCE modulation activity at different compound concentrations in MDA-MB-231 breast cancer cells. We have discovered 2-APB derivatives that block SOCE at low concentrations, at which 2-APB usually enhances SOCE.

Heterologous expression of polycystin-1 inhibits endoplasmic reticulum calcium leak in stably transfected MDCK cells

2008 ◽  
Vol 294 (6) ◽  
pp. F1279-F1286 ◽  
Author(s):  
Kimberly H. Weber ◽  
Eun Kyung Lee ◽  
Uma Basavanna ◽  
Sabina Lindley ◽  
Roy C. Ziegelstein ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Calcium Release ◽  
Mdck Cells ◽  
Calcium Ionophore ◽  
Calcium Flux ◽  
Calcium Stores ◽  
Endoplasmic Reticulum Calcium ◽  
Calcium Indicator ◽  
Luminal Calcium ◽  
Er Membrane

We previously found that polycystin-1 accelerated the decay of ligand-activated cytoplasmic calcium transients through enhanced reuptake of calcium into the endoplasmic reticulum (ER; Hooper KM, Boletta A, Germino GG, Hu Q, Ziegelstein RC, Sutters M. Am J Physiol Renal Physiol 289: F521–F530, 2005). Calcium flux across the ER membrane is determined by the balance of active uptake and passive leak. In the present study, we show that polycystin-1 inhibited calcium leak across the ER membrane, an effect that would explain the capacity of this protein to accelerate clearance of calcium from the cytoplasm following a calcium release response. Calcium leak was detected by measurement of the accumulation of calcium in the cytoplasm following treatment with thapsigargin. Heterologous polycystin-1, stably expressed in Madin-Darby canine kidney cells, attenuated the thapsigargin-induced calcium peak with no effect on basal calcium stores, mitochondrial calcium uptake, or extrusion of calcium across the plasma membrane. The capacity of polycystin-1 to limit the rate of decay of ER luminal calcium following inhibition of the pump was shown indirectly using the calcium ionophore ionomycin, and directly by loading the ER with a low-affinity calcium indicator. We conclude that disruption of ER luminal calcium homeostasis may contribute to the cyst phenotype in autosomal dominant polycystic kidney disease.

scholarly journals The tethering function of mitofusin2 controls osteoclast differentiation by modulating the Ca2+–NFATc1 axis

2020 ◽  
Vol 295 (19) ◽  
pp. 6629-6640 ◽  
Author(s):  
Anna Ballard ◽  
Rong Zeng ◽  
Allahdad Zarei ◽  
Christine Shao ◽  
Linda Cox ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Bone Mass ◽  
Intracellular Signaling ◽  
Osteoclast Differentiation ◽  
Calcium Entry ◽  
Calcium Handling ◽  
Mitochondrial Network ◽  
Female Mice ◽  
Mitochondrial Functions ◽  
Store Operated Calcium Entry

Dynamic regulation of the mitochondrial network by mitofusins (MFNs) modulates energy production, cell survival, and many intracellular signaling events, including calcium handling. However, the relative importance of specific mitochondrial functions and their dependence on MFNs vary greatly among cell types. Osteoclasts have many mitochondria, and increased mitochondrial biogenesis and oxidative phosphorylation enhance bone resorption, but little is known about the mitochondrial network or MFNs in osteoclasts. Because expression of each MFN isoform increases with osteoclastogenesis, we conditionally deleted MFN1 and MFN2 (double conditional KO (dcKO)) in murine osteoclast precursors, finding that this increased bone mass in young female mice and abolished osteoclast precursor differentiation into mature osteoclasts in vitro. Defective osteoclastogenesis was reversed by overexpression of MFN2 but not MFN1; therefore, we generated mice lacking only MFN2 in osteoclasts. MFN2-deficient female mice had increased bone mass at 1 year and resistance to Receptor Activator of NF-κB Ligand (RANKL)-induced osteolysis at 8 weeks. To explore whether MFN-mediated tethering or mitophagy is important for osteoclastogenesis, we overexpressed MFN2 variants defective in either function in dcKO precursors and found that, although mitophagy was dispensable for differentiation, tethering was required. Because the master osteoclastogenic transcriptional regulator nuclear factor of activated T cells 1 (NFATc1) is calcium-regulated, we assessed calcium release from the endoplasmic reticulum and store-operated calcium entry and found that the latter was blunted in dcKO cells. Restored osteoclast differentiation by expression of intact MFN2 or the mitophagy-defective variant was associated with normalization of store-operated calcium entry and NFATc1 levels, indicating that MFN2 controls mitochondrion–endoplasmic reticulum tethering in osteoclasts.

scholarly journals Regulation of store-operated calcium entry during cell division

2012 ◽  
Vol 40 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Jeremy T. Smyth ◽  
James W. Putney
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Recent Work ◽  
Calcium Entry ◽  
Store Operated Calcium Entry ◽  
Dividing Cells ◽  
Complex Mechanisms ◽  
Molecular Components ◽  
Ca2 Channels

Store-operate Ca2+ channels gate Ca2+ entry into the cytoplasm in response to the depletion of Ca2+ from endoplasmic reticulum Ca2+ stores. The major molecular components of store-operated Ca2+ entry are STIM (stromal-interacting molecule) 1 (and in some instances STIM2) that serves as the endoplasmic reticulum Ca2+ sensor, and Orai (Orai1, Orai2 and Orai3) which function as pore-forming subunits of the store-operated channel. It has been known for some time that store-operated Ca2+ entry is shut down during cell division. Recent work has revealed complex mechanisms regulating the functions and locations of both STIM1 and Orai1 in dividing cells.

scholarly journals Adrenocorticotropin Evokes Transient Elevations in Intracellular Free Calcium ([Ca2+]i) and Increases Basal [Ca2+]i in Resting Chondrocytes through a Phospholipase C-Dependent Mechanism

Endocrinology ◽  
2005 ◽  
Vol 146 (7) ◽  
pp. 3123-3132 ◽  
Author(s):  
Jodi F. Evans ◽  
Chwan-L Shen ◽  
Simcha Pollack ◽  
John F. Aloia ◽  
James K. Yeh
Keyword(s):  
Phospholipase C ◽  
Terminal Differentiation ◽  
Specific Inhibitor ◽  
Cartilage Degeneration ◽  
Calcium Entry ◽  
Intracellular Free Calcium ◽  
Melanocortin Receptors ◽  
Free Calcium ◽  
Matrix Gene ◽  
Store Operated Calcium Entry

Abstract Both clinical and in vitro evidence points to the involvement of the melanocortin peptide, ACTH, in the terminal differentiation of chondrocytes. Terminal differentiation along the endochondral pathway is responsible for linear growth, but also plays a role in osteoarthritic cartilage degeneration. Chondrocyte terminal differentiation is associated with an incremental increase in chondrocyte basal intracellular free calcium ([Ca2+]i), and ACTH agonism of melanocortin receptors is known to mobilize [Ca2+]i. Using differentiated resting chondrocytes highly expressing type II collagen and aggrecan, we examined the influence of both ACTH and dexamethasone treatment on matrix gene transcription and [Ca2+]i. Resting chondrocytes treated concurrently with dexamethasone and ACTH expressed matrix gene transcripts in a pattern consistent with that of rapid terminal differentiation. Using the fluorescent Ca2+ indicator, fura-2, we determined that ACTH evokes transient increases in [Ca2+]i and elevates basal Ca2+ levels in resting chondrocytes. The transient increases were initiated intracellularly, were abrogated by the phospholipase C-specific inhibitor, U73122, and were partly attenuated by myo-inositol 1,4,5-triphosphate receptor inhibition via 10 mm caffeine. The initial intracellular release also resulted in store-operated calcium entry, presumably through store-operated channels. Dexamethasone priming increased both the initial ACTH-evoked [Ca2+]i release and the subsequent store-operated calcium entry. These data demonstrate roles for ACTH and glucocorticoid in the regulation of chondrocyte terminal differentiation. Because the actions of ACTH are mediated through known G protein-coupled receptors, the melanocortin receptors, these data may provide a new therapeutic target in the treatment of growth deficiencies and cartilage degeneration.

scholarly journals Impaired Store-Operated Calcium Entry and STIM1 Loss Lead to Reduced Insulin Secretion and Increased Endoplasmic Reticulum Stress in the Diabetic β-Cell

Diabetes ◽  
2018 ◽  
Vol 67 (11) ◽  
pp. 2293-2304 ◽  
Author(s):  
Tatsuyoshi Kono ◽  
Xin Tong ◽  
Solaema Taleb ◽  
Robert N. Bone ◽  
Hitoshi Iida ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Insulin Secretion ◽  
Endoplasmic Reticulum Stress ◽  
Calcium Entry ◽  
Β Cell ◽  
Store Operated Calcium Entry

scholarly journals Crbn modulates calcium influx by regulating Orai1 during efferocytosis

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hyunji Moon ◽  
Chanhyuk Min ◽  
Gayoung Kim ◽  
Deokhwan Kim ◽  
Kwanhyeong Kim ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Molecular Mechanism ◽  
Regulatory Mechanism ◽  
Calcium Influx ◽  
Proteasomal Degradation ◽  
Calcium Flux ◽  
Apoptotic Cells ◽  
Crac Channel

Abstract Calcium flux regulating intracellular calcium levels is essential and modulated for efficient efferocytosis. However, the molecular mechanism by which calcium flux is modulated during efferocytosis remains elusive. Here, we report that Orai1, a Crbn substrate, is upregulated via its attenuated interaction with Crbn during efferocytosis, which increases calcium influx into phagocytes and thereby promotes efferocytosis. We found that Crbn deficiency promoted phagocytosis of apoptotic cells, which resulted from facilitated phagocytic cup closure and was nullified by a CRAC channel inhibitor. In addition, Orai1 associated with Crbn, resulting in ubiquitination and proteasomal degradation of Orai1 and alteration of SOCE-mediated calcium influx. The association of Orai1 with Crbn was attenuated during efferocytosis, leading to reduced ubiquitination of Orai1 and consequently upregulation of Orai1 and calcium influx. Collectively, our study reveals a regulatory mechanism by which calcium influx is modulated by a Crbn-Orai1 axis to facilitate efferocytosis.

scholarly journals Mycoplasma hyopneumoniae Increases Intracellular Calcium Release in Porcine Ciliated Tracheal Cells

2002 ◽  
Vol 70 (5) ◽  
pp. 2502-2506 ◽  
Author(s):  
Seung-Chun Park ◽  
Sirintorn Yibchok-Anun ◽  
Henrique Cheng ◽  
Theresa F. Young ◽  
Eileen L. Thacker ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Phospholipase C ◽  
Pertussis Toxin ◽  
Calcium Release ◽  
Mycoplasma Hyopneumoniae ◽  
Tracheal Epithelial Cells ◽  
Tracheal Epithelial ◽  
Mycoplasma Flocculare ◽  
Ciliated Epithelial Cells

ABSTRACT We investigated the effects of intact pathogenic Mycoplasma hyopneumoniae, nonpathogenic M. hyopneumoniae, and Mycoplasma flocculare on intracellular free Ca2+ concentrations ([Ca2+]i) in porcine ciliated tracheal epithelial cells. The ciliated epithelial cells had basal [Ca2+]i of 103 ± 3 nM (n = 217 cells). The [Ca2+]i increased by 250 ± 19 nM (n = 47 cells) from the basal level within 100 s of the addition of pathogenic M. hyopneumoniae strain 91-3 (300 μg/ml), and this increase lasted ∼60 s. In contrast, nonpathogenic M. hyopneumoniae and M. flocculare at concentrations of 300 μg/ml failed to increase [Ca2+]i. In Ca2+-free medium, pathogenic M. hyopneumoniae still increased [Ca2+]i in tracheal cells. Pretreatment with thapsigargin (1 μM for 30 min), which depleted the Ca2+ store in the endoplasmic reticulum, abolished the effect of M. hyoneumoniae. Pretreatment with pertussis toxin (100 ng/ml for 3 h) or U-73122 (2 μM for 100 s), an inhibitor of phospholipase C, also abolished the effect of M. hyopneumoniae. The administration of mastoparan 7, an activator of pertussis toxin-sensitive proteins Gi and Go, increased [Ca2+]i in ciliated tracheal cells. These results suggest that pathogenic M. hyopneumoniae activates receptors that are coupled to Gi or Go, which in turn activates a phospholipase C pathway, thereby releasing Ca2+ from the endoplasmic reticulum. Thus, an increase in Ca2+ may serve as a signal for the pathogenesis of M. hyopneumoniae.

scholarly journals Remodelling of the endoplasmic reticulum during store-operated calcium entry

2011 ◽  
Vol 103 (8) ◽  
pp. 365-380 ◽  
Author(s):  
Wei-Wei Shen ◽  
Maud Frieden ◽  
Nicolas Demaurex
Keyword(s):  
Endoplasmic Reticulum ◽  
Calcium Entry ◽  
Store Operated Calcium Entry
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