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Zandanell J, Wießner M, Bauer JW, Wagner RN. Stop codon readthrough as a treatment option for epidermolysis bullosa-Where we are and where we are going. Exp Dermatol 2024; 33:e15042. [PMID: 38459626 DOI: 10.1111/exd.15042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 01/24/2024] [Accepted: 02/17/2024] [Indexed: 03/10/2024]
Abstract
In the context of rare genetic diseases caused by nonsense mutations, the concept of induced stop codon readthrough (SCR) represents an attractive avenue in the ongoing search for improved treatment options. Epidermolysis bullosa (EB)-exemplary for this group of diseases-describes a diverse group of rare, blistering genodermatoses. Characterized by extreme skin fragility upon minor mechanical trauma, the most severe forms often result from nonsense mutations that lead to premature translation termination and loss of function of essential proteins at the dermo-epidermal junction. Since no curative interventions are currently available, medical care is mainly limited to alleviating symptoms and preventing complications. Complementary to attempts of gene, cell and protein therapy in EB, SCR represents a promising medical alternative. While gentamicin has already been examined in several clinical trials involving EB, other potent SCR inducers, such as ataluren, may also show promise in treating the hitherto non-curative disease. In addition to the extensively studied aminoglycosides and their derivatives, several other substance classes-non-aminoglycoside antibiotics and non-aminoglycoside compounds-are currently under investigation. The extensive data gathered in numerous in vitro experiments and the perspectives they reveal in the clinical setting will be discussed in this review.
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Affiliation(s)
- Johanna Zandanell
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Michael Wießner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Johann W Bauer
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Roland N Wagner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
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Wagner RN, Wießner M, Friedrich A, Zandanell J, Breitenbach-Koller H, Bauer JW. Emerging Personalized Opportunities for Enhancing Translational Readthrough in Rare Genetic Diseases and Beyond. Int J Mol Sci 2023; 24:6101. [PMID: 37047074 PMCID: PMC10093890 DOI: 10.3390/ijms24076101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Nonsense mutations trigger premature translation termination and often give rise to prevalent and rare genetic diseases. Consequently, the pharmacological suppression of an unscheduled stop codon represents an attractive treatment option and is of high clinical relevance. At the molecular level, the ability of the ribosome to continue translation past a stop codon is designated stop codon readthrough (SCR). SCR of disease-causing premature termination codons (PTCs) is minimal but small molecule interventions, such as treatment with aminoglycoside antibiotics, can enhance its frequency. In this review, we summarize the current understanding of translation termination (both at PTCs and at cognate stop codons) and highlight recently discovered pathways that influence its fidelity. We describe the mechanisms involved in the recognition and readthrough of PTCs and report on SCR-inducing compounds currently explored in preclinical research and clinical trials. We conclude by reviewing the ongoing attempts of personalized nonsense suppression therapy in different disease contexts, including the genetic skin condition epidermolysis bullosa.
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Affiliation(s)
- Roland N. Wagner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | - Michael Wießner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | - Andreas Friedrich
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
- Department of Biosciences, University of Salzburg, 5020 Salzburg, Austria
| | - Johanna Zandanell
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | | | - Johann W. Bauer
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
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Wagner RN, Piñón Hofbauer J, Wally V, Kofler B, Schmuth M, De Rosa L, De Luca M, Bauer JW. Epigenetic and metabolic regulation of epidermal homeostasis. Exp Dermatol 2021; 30:1009-1022. [PMID: 33600038 PMCID: PMC8359218 DOI: 10.1111/exd.14305] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/11/2021] [Accepted: 02/14/2021] [Indexed: 02/06/2023]
Abstract
Continuous exposure of the skin to environmental, mechanical and chemical stress necessitates constant self‐renewal of the epidermis to maintain its barrier function. This self‐renewal ability is attributed to epidermal stem cells (EPSCs), which are long‐lived, multipotent cells located in the basal layer of the epidermis. Epidermal homeostasis – coordinated proliferation and differentiation of EPSCs – relies on fine‐tuned adaptations in gene expression which in turn are tightly associated with specific epigenetic signatures and metabolic requirements. In this review, we will briefly summarize basic concepts of EPSC biology and epigenetic regulation with relevance to epidermal homeostasis. We will highlight the intricate interplay between mitochondrial energy metabolism and epigenetic events – including miRNA‐mediated mechanisms – and discuss how the loss of epigenetic regulation and epidermal homeostasis manifests in skin disease. Discussion of inherited epidermolysis bullosa (EB) and disorders of cornification will focus on evidence for epigenetic deregulation and failure in epidermal homeostasis, including stem cell exhaustion and signs of premature ageing. We reason that the epigenetic and metabolic component of epidermal homeostasis is significant and warrants close attention. Charting epigenetic and metabolic complexities also represents an important step in the development of future systemic interventions aimed at restoring epidermal homeostasis and ameliorating disease burden in severe skin conditions.
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Affiliation(s)
- Roland N Wagner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Josefina Piñón Hofbauer
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Verena Wally
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kofler
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Matthias Schmuth
- Department of Dermatology, Medical University Innsbruck, Innsbruck, Austria
| | - Laura De Rosa
- Holostem Terapie Avanzate S.r.l., Center for Regenerative Medicine "Stefano Ferrari", Modena, Italy
| | - Michele De Luca
- Center for Regenerative Medicine "Stefano Ferrari", Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Johann W Bauer
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
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Abstract
Background HIV-1 protease (PR) is essential for viral infectivity as it cleaves Gag and Gag-Pol polyprotein precursors during viral maturation. Recent evidence suggests that cellular proteins can also be cleaved by PR, perhaps representing an important viral strategy to counter host defense mechanisms. Receptor-interacting protein kinase 1 (RIPK1) and RIPK2 belong to a family of serine/threonine kinases with conserved domain architecture and important functions in apoptosis, necrosis and innate immunity. Results We found that RIPK1 and RIPK2 but not other members of the RIP kinase family are cleaved by HIV-1 PR. In RIPK1, we identified a putative PR cleavage site; a mutation at this site rendered RIPK1 resistant to PR cleavage. RIPK1 and RIPK2 were cleaved during HIV-1 infection of T cell lines or primary activated CD4+ T cells. Interfering with the viral life cycle at different stages by the addition of specific inhibitors against RT, integrase, or PR, completely prevented RIPK1 and RIPK2 cleavage. Cleavage of RIPK1 disrupted RIPK1/RIPK3 complex formation and RIPK1-mediated induction of NF-kB. Conclusions These findings indicate that RIPK1 and RIPK2 are targets of HIV-1 PR activity during infection, and their inactivation may contribute to modulation of cell death and host defense pathways by HIV-1. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0200-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Roland N Wagner
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, USA. .,Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
| | - John C Reed
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, USA. .,Roche, Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland.
| | - Sumit K Chanda
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, USA.
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Traweger A, Toepfer S, Wagner RN, Zweimueller-Mayer J, Gehwolf R, Lehner C, Tempfer H, Krizbai I, Wilhelm I, Bauer HC, Bauer H. Beyond cell-cell adhesion: Emerging roles of the tight junction scaffold ZO-2. Tissue Barriers 2014; 1:e25039. [PMID: 24665396 PMCID: PMC3885625 DOI: 10.4161/tisb.25039] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/14/2013] [Accepted: 05/14/2013] [Indexed: 01/28/2023] Open
Abstract
Zonula occludens proteins (ZO-1, ZO-2, ZO-3), which belong to the family of membrane-associated guanylate kinase (MAGUK) homologs, serve as molecular hubs for the assembly of multi-protein networks at the cytoplasmic surface of intercellular contacts in epithelial and endothelial cells. These multi-PDZ proteins exert crucial functions in the structural organization of intercellular contacts and in transducing intracellular signals from the plasma membrane to the nucleus. The junctional MAGUK protein ZO-2 not only associates with the C-terminal PDZ-binding motif of various transmembrane junctional proteins but also transiently targets to the nucleus and interacts with a number of nuclear proteins, thereby modulating gene expression and cell proliferation. Recent evidence suggests that ZO-2 is also involved in stress response and cytoprotective mechanisms, which further highlights the multi-faceted nature of this PDZ domain-containing protein. This review focuses on ZO-2 acting as a molecular scaffold at the cytoplasmic aspect of tight junctions and within the nucleus and discusses additional aspects of its cellular activities. The multitude of proteins interacting with ZO-2 and the heterogeneity of proteins either influencing or being influenced by ZO-2 suggests an exceptional functional capacity of this protein far beyond merely serving as a structural component of cellular junctions.
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Affiliation(s)
- Andreas Traweger
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria
| | - Sebastian Toepfer
- University of Salzburg; Department of Organismic Biology; Salzburg, Austria
| | - Roland N Wagner
- Sanford-Burnham Medical Research Institute; La Jolla, CA USA
| | | | - Renate Gehwolf
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria
| | - Christine Lehner
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria
| | - Herbert Tempfer
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria
| | - Istvan Krizbai
- Institute of Biophysics; Biological Research Centre; Szeged, Hungary
| | - Imola Wilhelm
- Institute of Biophysics; Biological Research Centre; Szeged, Hungary
| | - Hans-Christian Bauer
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria ; University of Salzburg; Department of Organismic Biology; Salzburg, Austria
| | - Hannelore Bauer
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; University of Salzburg; Department of Organismic Biology; Salzburg, Austria
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Eibl C, Grigoriu S, Hessenberger M, Wenger J, Puehringer S, Pinheiro AS, Wagner RN, Proell M, Reed JC, Page R, Diederichs K, Peti W. Structural and functional analysis of the NLRP4 pyrin domain. Biochemistry 2012; 51:7330-41. [PMID: 22928810 PMCID: PMC3445046 DOI: 10.1021/bi3007059] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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NLRP4 is a member of the nucleotide-binding and leucine-rich
repeat
receptor (NLR) family of cytosolic receptors and a member of an inflammation
signaling cascade. Here, we present the crystal structure of the NLRP4
pyrin domain (PYD) at 2.3 Å resolution. The NLRP4 PYD is a member
of the death domain (DD) superfamily and adopts a DD fold consisting
of six α-helices tightly packed around a hydrophobic core, with
a highly charged surface that is typical of PYDs. Importantly, however,
we identified several differences between the NLRP4 PYD crystal structure
and other PYD structures that are significant enough to affect NLRP4
function and its interactions with binding partners. Notably, the
length of helix α3 and the α2−α3 connecting
loop in the NLRP4 PYD are unique among PYDs. The apoptosis-associated
speck-like protein containing a CARD (ASC) is an adaptor protein whose
interactions with a number of distinct PYDs are believed to be critical
for activation of the inflammatory response. Here, we use co-immunoprecipitation,
yeast two-hybrid, and nuclear magnetic resonance chemical shift perturbation
analysis to demonstrate that, despite being important for activation
of the inflammatory response and sharing several similarities with
other known ASC-interacting PYDs (i.e., ASC2), NLRP4 does not interact
with the adaptor protein ASC. Thus, we propose that the factors governing
homotypic PYD interactions are more complex than the currently accepted
model, which states that complementary charged surfaces are the main
determinants of PYD–PYD interaction specificity.
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Affiliation(s)
- Clarissa Eibl
- Department of Molecular Biology, University of Salzburg, 5020 Salzburg, Austria
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D'Osualdo A, Weichenberger CX, Wagner RN, Godzik A, Wooley J, Reed JC. CARD8 and NLRP1 undergo autoproteolytic processing through a ZU5-like domain. PLoS One 2011; 6:e27396. [PMID: 22087307 PMCID: PMC3210808 DOI: 10.1371/journal.pone.0027396] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 10/15/2011] [Indexed: 01/06/2023] Open
Abstract
The "Function to Find Domain" (FIIND)-containing proteins CARD8 (Cardinal; Tucan) and NLRP1 (NALP1; NAC) are well known components of inflammasomes, multiprotein complexes responsible for activation of caspase-1, a regulator of inflammation and innate immunity. Although identified many years ago, the role of the FIIND is unknown. Here, we report that CARD8 and NLRP1 undergo autoproteolytic cleavage at a conserved SF/S motif within the FIIND. Using bioinformatics and computational modeling approaches, we detected striking structural similarity between the FIIND and the ZU5-UPA domain present in the autoproteolytic protein PIDD. This allowed us to generate a three-dimensional model and to gain insights in the molecular mechanism of the cleavage. Site-directed mutagenesis experiments revealed that the second serine of the SF/S motif is required for CARD8 and NLRP1 autoproteolysis. Furthermore, we discovered an important function for conserved glutamic acid and histidine residues, located in proximity of the cleavage site in regulating the autoprocessing efficiency. Altogether, these results identify a function for the FIIND and show that CARD8 and NLRP1 are ZU5-UPA domain-containing autoproteolytic proteins, thus suggesting a novel mechanism for regulating innate immune responses.
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Affiliation(s)
- Andrea D'Osualdo
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Christian X. Weichenberger
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- Department of Pharmacology, University of California San Diego, La Jolla, California, United States of America
- Center for Biomedicine, European Academy of Bozen/Bolzano (EURAC), Bolzano, Italy
| | - Roland N. Wagner
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Adam Godzik
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - John Wooley
- Department of Pharmacology, University of California San Diego, La Jolla, California, United States of America
| | - John C. Reed
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
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Zurek B, Proell M, Wagner RN, Schwarzenbacher R, Kufer TA. Mutational analysis of human NOD1 and NOD2 NACHT domains reveals different modes of activation. Innate Immun 2011; 18:100-11. [PMID: 21310790 DOI: 10.1177/1753425910394002] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Nucleotide-binding oligomerization domain-containing protein (NOD)1 and NOD2 are intracellular pattern recognition receptors (PRRs) of the nucleotide-binding domain and leucine-rich repeat containing (NLR) gene family involved in innate immune responses. Their centrally located NACHT domain displays ATPase activity and is necessary for activation and oligomerization leading to inflammatory signaling responses. Mutations affecting key residues of the ATPase domain of NOD2 are linked to severe auto-inflammatory diseases, such as Blau syndrome and early-onset sarcoidosis. By mutational dissection of the ATPase domain function, we show that the NLR-specific extended Walker B box (DGhDE) can functionally replace the canonical Walker B sequence (DDhWD) found in other ATPases. A requirement for an intact Walker A box and the magnesium-co-ordinating aspartate of the classical Walker B box suggest that an initial ATP hydrolysis step is necessary for activation of both NOD1 and NOD2. In contrast, a Blau-syndrome associated mutation located in the extended Walker B box of NOD2 that results in higher autoactivation and ligand-induced signaling does not affect NOD1 function. Moreover, mutation of a conserved histidine in the NACHT domain also has contrasting effects on NOD1 and NOD2 mediated NF-κB activation. We conclude that these two NLRs employ different modes of activation and propose distinct models for activation of NOD1 and NOD2.
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Affiliation(s)
- Birte Zurek
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany
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Abstract
Members of the Nod-like receptor (NLR) family recognize intracellular pathogens and recruit a variety of effector molecules, including pro-caspases and kinases, which in turn are implicated in cytokine processing and NF-κB activation. In order to elucidate the intricate network of NLR signaling, which is still fragmentary in molecular terms, we applied comprehensive yeast two-hybrid analysis for unbiased evaluation of physical interactions between NLRs and their adaptors (ASC, CARD8) as well as kinase RIPK2 and inflammatory caspases (C1, C2, C4, C5) under identical conditions. Our results confirmed the interaction of NOD1 and NOD2 with RIPK2, and between NLRP3 and ASC, but most importantly, our studies revealed hitherto unrecognized interactions of NOD2 with members of the NLRP subfamily. We found that NOD2 specifically and directly interacts with NLRP1, NLRP3 and NLRP12. Furthermore, we observed homodimerization of the RIPK2 CARD domains and identified residues in NOD2 critical for interaction with RIPK2. In conclusion, our work provides further evidence for the complex network of protein-protein interactions underlying NLR function.
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Affiliation(s)
- Roland N. Wagner
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Martina Proell
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Thomas A. Kufer
- Institute of Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany
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