Transactivation of the grp78 promoter by Ca2+ depletion. A comparative analysis with A23187 and the endoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin

Li, W W; Alexandre, S; Cao, Xiaojuan; Lee, A S

doi:10.1016/s0021-9258(19)50300-3

Cited by 210 publications

(19 citation statements)

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“…Both mock-transfected HEK293T cells and HEK293T cells co-expressing Luc-HSF1 / YFP-HSF1 proteins were incubated overnight with increasing concentrations of Thapsigargin. Addition of Thapsigargin, which is a well-known competitive inhibitor of the sarco/endoplasmic reticulum Calcium ATPase (SERCA), leads to emptying the intracellular calcium stores (Burnay et al 1994) and the subsequent triggering of endoplasmic reticulum stress following prolonged exposure (Li et al 1993). Overnight treatment with 10 nM Thapsigargin efficiently induced an ER stress as shown by the increase in BiP protein expression level (Fig.…”

Section: Resultsmentioning

confidence: 99%

Effects of radiofrequency field exposure on proteotoxic-induced and heat-induced HSF1 response in live cells using the bioluminescence resonance energy transfer technique

Poque

Ruigrok

Arnaud‐Cormos

et al. 2021

Cell Stress and Chaperones

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As of today, only acute effects of RF fields have been confirmed to represent a potential health hazard and they are attributed to non-specific heating (≥1 °C) under high-level exposure. Yet, the possibility that environmental RF impact living matter in the absence of temperature elevation needs further investigation. Since HSF1 is both a thermosensor and the master regulator of heat-shock stressresponse in eukaryotes, it remains to assess HSF1 activation in live cells under exposure to low-level RF signals. We thus measured basal, temperature-induced, and chemically-induced HSF1 trimerization, a mandatory step on the cascade of HSF1 activation, under RF exposure to Continuous Wave (CW), Global System for Mobile (GSM), and Wi-Fi modulated 1800 MHz signals, using a Bioluminescence Resonance Energy Transfer technique (BRET) probe. Our results show that, as expected, HSF1 is heat-activated by acute exposure of transiently-transfected HEK293T cells to a CW RF field at a Specific Absorption Rate of 24 W/kg for 30 min. However, we found no evidence of HSF1 activation under the same RF exposure condition when the cell culture medium temperature was fixed. We also found no experimental evidence that, at a fixed temperature, chronic RF exposure for 24 h at a SAR of 1.5 and 6 W/kg altered the potency or the maximal capability of the proteasome inhibitor MG132 to activate HSF1, whatever signal used. We only found that RF exposure to CW signals (1.5 and 6 W/kg) and GSM signals (1.5 W/kg) for 24 h marginally decreased basal HSF1 activity.

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Section: Resultsmentioning

confidence: 99%

Effects of radiofrequency field exposure on proteotoxic-induced and heat-induced HSF1 response in live cells using the bioluminescence resonance energy transfer technique

Poque

Ruigrok

Arnaud‐Cormos

et al. 2021

Cell Stress and Chaperones

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“…reactive oxygen species generation, 30 and increases intracellular Ca 2 þ in PTCs. 31 They may be potential mechanisms of induction of ER stress in PTCs exposed to albumin, as alteration in calcium mobilization 32,33 or redox status 34,35 is known to bring about ER stress. We used fatty acid-free albumin, alleviating the concern that the observed effect in our studies might be mediated by a non-proteinaceous compound attached to albumin in the manufacturing process.…”

Section: Discussionmentioning

confidence: 99%

Albumin induces endoplasmic reticulum stress and apoptosis in renal proximal tubular cells

Ohse

Inagi

Tanaka

et al. 2006

Kidney International

185

158

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Chronic proteinuria appears to be a key factor in tubulointerstitial damage. Recent studies have emphasized a pathogenic role of endoplasmic reticulum (ER) stress which is induced by the accumulation of misfolded proteins in ER, extracellular stress, etc. In the present study, we investigated ER stress and ER stress-induced apoptosis in proximal tubular cells (PTCs). Immortalized rat PTCs (IRPTCs) were cultured with bovine serum albumin (BSA). The viability of IRPTCs decreased proportionately with BSA overload in a time-dependent manner. Quantitative real-time polymerase chain reaction analysis revealed that 40 mg/ml BSA increases mRNA of ER stress markers by 7.7- and 4.6-fold (glucose-regulated protein 78 (GRP78) and oxygen-regulated protein 150 (ORP150), respectively) as compared to control. The increased expression of ORP150 and GRP78 in IRPTCs with albumin overload was detected by Western blot and immunofluorescence study. These in vitro observations were supported by in vivo studies, which demonstrated that ER stress proteins were upregulated at PTCs in experimental proteinuric rats. Furthermore, increased ER stress-induced apoptosis and activation of caspase-12 were observed in IRPTCs with albumin overload and kidneys of experimental proteinuric rats. We confirmed that apoptotic cell death was attenuated by co-incubation with caspase-3 inhibitor or calpain inhibitors. These results indicate that the ER stress-induced apoptosis pathway contributed to the insult of tubular cells by proteinuria. In conclusion, renal tubular cells exposed to high protein load suffer from ER stress. ER stress may subsequently lead to tubular damage by activation of caspase-12.

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“…We wanted to explore this possibility by impeding the activation of IP 3 R using thapsigargin (THA), a Ca 2+ ATPase inhibitor [52]. Thapsigargin is also known to produce ER stress to the cells since this treatment depletes Ca 2+ stores from ER, and therefore increases GRP78 expression as part of the canonical unfolded protein response [53]. Figure 4F shows that thapsigargin affects cell viability similarly to tunicamycin treatment in GFP-control cells and that CCCP concomitant treatment prevents cell death as observed with Tun.…”

Section: Mitophagy Induction By Grp78 Overexpression Mediates Neuroprotectionmentioning

confidence: 99%

GRP78 Overexpression Triggers PINK1-IP3R-Mediated Neuroprotective Mitophagy

et al. 2021

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An experimental model of spinal root avulsion (RA) is useful to study causal molecular programs that drive retrograde neurodegeneration after neuron-target disconnection. This neurodegenerative process shares common characteristics with neuronal disease-related processes such as the presence of endoplasmic reticulum (ER) stress and autophagy flux blockage. We previously found that the overexpression of GRP78 promoted motoneuronal neuroprotection after RA. After that, we aimed to unravel the underlying mechanism by carrying out a comparative unbiased proteomic analysis and pharmacological and genetic interventions. Unexpectedly, mitochondrial factors turned out to be most altered when GRP78 was overexpressed, and the abundance of engulfed mitochondria, a hallmark of mitophagy, was also observed by electronic microscopy in RA-injured motoneurons after GRP78 overexpression. In addition, GRP78 overexpression increased LC3-mitochondria tagging, promoted PINK1 translocation, mitophagy induction, and recovered mitochondrial function in ER-stressed cells. Lastly, we found that GRP78-promoted pro-survival mitophagy was mediated by PINK1 and IP3R in our in vitro model of motoneuronal death. This data indicates a novel relationship between the GRP78 chaperone and mitophagy, opening novel therapeutical options for drug design to achieve neuroprotection.

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Transactivation of the grp78 promoter by Ca2+ depletion. A comparative analysis with A23187 and the endoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin

Cited by 210 publications

References 1 publication

Effects of radiofrequency field exposure on proteotoxic-induced and heat-induced HSF1 response in live cells using the bioluminescence resonance energy transfer technique

Effects of radiofrequency field exposure on proteotoxic-induced and heat-induced HSF1 response in live cells using the bioluminescence resonance energy transfer technique

Albumin induces endoplasmic reticulum stress and apoptosis in renal proximal tubular cells

GRP78 Overexpression Triggers PINK1-IP3R-Mediated Neuroprotective Mitophagy

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