Ultraviolet A Induces Endoplasmic Reticulum Stress Response in Human Dermal Fibroblasts

Komori, Ryota; Taniguchi, Masaru; Ichikawa, Yoshiaki; Uemura, Aya; Oku, Masaya; Wakabayashi, Shigeo; Higuchi, Kazuhiko; Yoshida, Hiderou

doi:10.1247/csf.11041

Cited by 28 publications

(27 citation statements)

References 24 publications

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“…2B). Moreover, UVA-activation of the cellular antioxidant response was substantiated by immunodetection of increased protein levels of the transcription factor Nrf2 and its downstream target heme oxygenase-1 (HO-1; encoded by HMOX1 ) [36–38]. Supporting the mechanistic involvement of photo-oxidative stress in UVA inactivation of both cysteine-dependent cathepsins B and L, loss of cathepsin B and L enzymatic activities was antagonized significantly if irradiation occurred in the presence of the thiol-antioxidant N-acetyl-L-cysteine (NAC, 10 mM), a protective effect not observed with the aspartate-dependent cathepsin D (Fig.…”

Section: Resultsmentioning

confidence: 99%

UVA causes dual inactivation of cathepsin B and L underlying lysosomal dysfunction in human dermal fibroblasts

Lamore

Wondrak

2013

Journal of Photochemistry and Photobiology B: Biology

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Cutaneous exposure to chronic solar UVA-radiation is a causative factor in photocarcinogenesis and photoaging. Recently, we have identified the thiol-dependent cysteine-protease cathepsin B as a novel UVA-target undergoing photo-oxidative inactivation upstream of autophagic-lysosomal dysfunction in fibroblasts. In this study, we examined UVA effects on a wider range of cathepsins and explored the occurrence of UVA-induced cathepsin inactivation in other cultured skin cell types. In dermal fibroblasts, chronic exposure to non-cytotoxic doses of UVA caused pronounced inactivation of the lysosomal cysteine-proteases cathepsin B and L, effects not observed in primary keratinocytes and occurring only to a minor extent in primary melanocytes. In order to determine if UVA-induced lysosomal impairment requires single or dual inactivation of cathepsin B and/or L, we used a genetic approach (siRNA) to selectively downregulate enzymatic activity of these target cathepsins. Monitoring an established set of protein markers (including LAMP1, LC3-II, and p62) and cell ultrastructural changes detected by electron microscopy, we observed that only dual genetic antagonism (targeting both CTSB and CTSL expression) could mimic UVA-induced autophagic-lysosomal alterations, whereas single knockdown (targeting CTSB or CTSL only) did not display ‘UVA-mimetic’ effects failing to reproduce the UVA-induced phenotype. Taken together, our data demonstrate that chronic UVA inhibits both cathepsin B and L enzymatic activity and that dual inactivation of both enzymes is a causative factor underlying UVA-induced impairment of lysosomal function in dermal fibroblasts.

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Section: Resultsmentioning

confidence: 99%

UVA causes dual inactivation of cathepsin B and L underlying lysosomal dysfunction in human dermal fibroblasts

Lamore

Wondrak

2013

Journal of Photochemistry and Photobiology B: Biology

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“…Transfection of plasmid DNAs was performed by either the calcium phosphate method or lipofection using FuGene (Roche, Basel, Switzerland). After transfection, cells were treated with Golgi stress inducers for 12-16 h, washed three times with PBS and harvested for immunoblotting and immunocytochemistry (Komori et al, 2012). For luciferase assays, transfected cells were incubated in fresh medium for an additional 6 h for recovery before harvest (Oku et al, 2011).…”

Section: Cell Culture and Transfectionmentioning

confidence: 99%

TFE3 Is a bHLH-ZIP-type Transcription Factor that Regulates the Mammalian Golgi Stress Response

Taniguchi

Nadanaka

Tanakura

et al. 2015

Cell Struct. Funct.

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ABSTRACT. The Golgi stress response is a mechanism by which, under conditions of insufficient Golgi function (Golgi stress), the transcription of Golgi-related genes is upregulated through an enhancer, the Golgi apparatus stress response element (GASE), in order to maintain homeostasis in the Golgi. The molecular mechanisms associated with GASE remain to be clarified. Here, we identified TFE3 as a GASE-binding transcription factor. TFE3 was phosphorylated and retained in the cytoplasm in normal growth conditions, whereas it was dephosphorylated, translocated to the nucleus and activated Golgi-related genes through GASE under conditions of Golgi stress, e.g. in response to inhibition of oligosaccharide processing in the Golgi apparatus. From these observations, we concluded that the TFE3-GASE pathway is one of the regulatory pathways of the mammalian Golgi stress response, which regulates the expression of glycosylation-related proteins in response to insufficiency of glycosylation in the Golgi apparatus.

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“…The pellet was suspended in 20 µl of ice-cold PBS containing protease inhibitors (100 µM AEBSF, 80 µM aprotinin, 1.5 µM E-64, 2 µM leupeptin, 5 µM bestatin and 1 µM pepstatin A, 10 µM MG132), mixed with 20 µl of 4×SDS-sample buffer (200 mM Tris-Cl (pH 6.8), 400 mM DTT, 8% SDS, and 40% glycerol), and immediately boiled at 100°C for 10 min (Komori et al, 2012). Portions of samples (10 µl) were subjected to SDS-polyacrylamide gel electrophoresis using 4-20% gradient gels, transferred onto a Hybond-P membrane (GE), and incubated with various antisera, in accordance with the standard protocol (Sambrook et al, 1989).…”

Section: Immunoblottingmentioning

confidence: 99%

“…When nascent proteins are malfolded or unfolded in the ER, they are disposed of by a mechanism called ER-associated degradation (ERAD) (Bernasconi and Molinari, 2011;Hampton, 2002;Hebert et al, 2010). When the synthesis of secretory proteins is increased and overwhelms the capacity of ER chaperones and ERAD components, or when environmental stresses such as ultraviolet irradiation hamper proper folding of secretory proteins (Komori et al, 2012;Mera et al, 2010;Wu et al, 2002), unfolded proteins accumulate in the ER (ER stress) and induce apoptotic cell death. To cope with ER stress, eukaryotic cells activate a cytoprotective mechanism called the ER stress response (also called the unfolded protein response) to upregulate expression of ER chaperones as well as ERAD components; this process is well conserved from yeast to mammals Mori, 2009;Tabas and Ron, 2011;Walter and Ron, 2011;Wang and Kaufman, 2012;Yoshida, 2009).…”

Section: Introductionmentioning

confidence: 99%

UBC9 Regulates the Stability of XBP1, a Key Transcription Factor Controlling the ER Stress Response

Uemura

Taniguchi

Matsuo

et al. 2013

Cell Struct. Funct.

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ABSTRACT. XBP1 is a key transcription factor regulating the mammalian endoplasmic reticulum (ER) stress response, which is a cytoprotective mechanism for dealing with an accumulation of unfolded proteins in the ER (ER stress). The expression of XBP1 is regulated by two different mechanisms: mRNA splicing and protein stability. When ER stress occurs, unspliced XBP1 mRNA is converted to mature mRNA, from which an active transcription factor, pXBP1(S), is translated and activates the transcription of ER-related genes to dispose of unfolded proteins. In the absence of ER stress, pXBP1(U) is translated from unspliced XBP1 mRNA and enhances the degradation of pXBP1(S). Here, we analyzed the regulatory mechanism of pXBP1(S) stability, and found that a SUMO-conjugase, UBC9, specifically bound to the leucine zipper motif of pXBP1(S) and increased the stability of pXBP1(S). Suppression of UBC9 expression by RNA interference reduced both the expression of pXBP1(S) and ER stress-induced transcription by pXBP1(S). Interestingly, overexpression of a UBC9 mutant deficient in SUMO-conjugating activity was able to increase pXBP1(S) expression as well as wild-type UBC9, indicating that UBC9 stabilizes pXBP1(S) without conjugating SUMO moieties. From these observations, we concluded that UBC9 is a novel regulator of the mammalian ER stress response.

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Ultraviolet A Induces Endoplasmic Reticulum Stress Response in Human Dermal Fibroblasts

Cited by 28 publications

References 24 publications

UVA causes dual inactivation of cathepsin B and L underlying lysosomal dysfunction in human dermal fibroblasts

UVA causes dual inactivation of cathepsin B and L underlying lysosomal dysfunction in human dermal fibroblasts

TFE3 Is a bHLH-ZIP-type Transcription Factor that Regulates the Mammalian Golgi Stress Response

UBC9 Regulates the Stability of XBP1, a Key Transcription Factor Controlling the ER Stress Response

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