Browsing by Author "Fuentes, Ignacia"
Now showing 1 - 11 of 11
Results Per Page
Sort Options
- ItemA Nuclear Gene Encoding the Iron-Sulfur Subunit of Mitochondrial Complex II Is Regulated by B3 Domain Transcription Factors during Seed Development in Arabidopsis(AMER SOC PLANT BIOLOGISTS, 2009) Roschzttardtz, Hannetz; Fuentes, Ignacia; Vasquez, Marcos; Corvalan, Claudia; Leon, Gabriel; Gomez, Isabel; Araya, Alejandro; Holuigue, Loreto; Vicente Carbajosa, Jesus; Jordana, XavierMitochondrial complex II (succinate dehydrogenase) is part of the tricarboxylic acid cycle and the respiratory chain. Three nuclear genes encode its essential iron-sulfur subunit in Arabidopsis (Arabidopsis thaliana). One of them, SUCCINATE DEHYDROGENASE2-3 (SDH2-3), is specifically expressed in the embryo during seed maturation, suggesting that SDH2-3 may have a role as the complex II iron-sulfur subunit during embryo maturation and/or germination. Here, we present data demonstrating that three abscisic acid-responsive elements and one RY-like enhancer element, present in the SDH2-3 promoter, are involved in embryo-specific SDH2-3 transcriptional regulation. Furthermore, we show that ABSCISIC ACID INSENSITIVE3 (ABI3), FUSCA3 (FUS3), and LEAFY COTYLEDON2, three key B3 domain transcription factors involved in gene expression during seed maturation, control SDH2-3 expression. Whereas ABI3 and FUS3 interact with the RY element in the SDH2-3 promoter, the abscisic acid-responsive elements are shown to be a target for bZIP53, a member of the basic leucine zipper (bZIP) family of transcription factors. We show that group S1 bZIP53 protein binds the promoter as a heterodimer with group C bZIP10 or bZIP25. To the best of our knowledge, the SDH2-3 promoter is the first embryo-specific promoter characterized for a mitochondrial respiratory complex protein. Characterization of succinate dehydrogenase activity in embryos from two homozygous sdh2-3 mutant lines permits us to conclude that SDH2-3 is the major iron-sulfur subunit of mature embryo complex II. Finally, the absence of SDH2-3 in mutant seeds slows down their germination, pointing to a role of SDH2-3-containing complex II at an early step of germination.
- ItemAntiviral drugs prolong survival in murine recessive dystrophic epidermolysis bullosa(2024) Tartaglia, Grace; Fuentes, Ignacia; Patel, Neil; Varughese, Abigail; Israel, Lauren E.; Park, Pyung Hun; Alexander, Michael H.; Poojan, Shiv; Cao, Qingqing; Solomon, Brenda; Padron, Zachary M.; Dyer, Jonathan A.; Mellerio, Jemima E.; McGrath, John A.; Palisson, Francis; Salas-Alanis, Julio; Han, Lin; South, Andrew P.Recessive dystrophic epidermolysis bullosa (RDEB) is a rare inherited skin disease characterized by defects in type VII collagen leading to a range of fibrotic pathologies resulting from skin fragility, aberrant wound healing, and altered dermal fibroblast physiology. Using a novel in vitro model of fibrosis based on endogenously produced extracellular matrix, we screened an FDA-approved compound library and identified antivirals as a class of drug not previously associated with anti-fibrotic action. Preclinical validation of our lead hit, daclatasvir, in a mouse model of RDEB demonstrated significant improvement in fibrosis as well as overall quality of life with increased survival, weight gain and activity, and a decrease in pruritus-induced hair loss. Immunohistochemical assessment of daclatasvir-treated RDEB mouse skin showed a reduction in fibrotic markers, which was supported by in vitro data demonstrating TGF beta pathway targeting and a reduction of total collagen retained in the extracellular matrix. Our data support the clinical development of antivirals for the treatment of patients with RDEB and potentially other fibrotic diseases.
- ItemBetaine-urea deep eutectic solvent improves imipenem antibiotic activity(2022) Olivares, Belen; Martinez, Fabian A.; Ezquer, Marcelo; Morales, Bernardo J.; Fuentes, Ignacia; Calvo, Margarita; Campodonico, Paola R.Beta-lactam antibiotics are highly unstable in aqueous media, which may lead to subclinical concentrations, antimicrobial resistance and therapeutic failure. In previous work we demonstrated that a natural deep eutectic solvent consisting of betaine and urea (BU) is capable of improving the stability of some beta-lactams, including imipenem (IMP), the most unstable antibiotic of the family. Here, IMP-BU was studied by selective protonic Nuclear Overhauser Effect Spectroscopy Magnetic Resonance (H-1 NOESY NMR) to gain insight into the mechanism by which BU protects IMP. The kinetics of IMP release and its antibacterial activity were evaluated in diffusional, time-kill and antibiofilm assays. It was found that BU is a protective matrix which allows a fast release of IMP, resulting in superior antibacterial activity when compared to IMP in aqueous solution, both against bacteria growing in planktonic form and in biofilms. Furthermore, it was shown that BU is nontoxic when evaluated in fibroblast primary cell cultures and in organotypic skin cultures, and is not immunogenic when tested in vitro in macrophage cultures, suggesting that BU has potential application as a biomaterial or excipient. (C) 2022 Published by Elsevier B.V.
- ItemCharacterisation of the pathophysiology of neuropathy and sensory dysfunction in a mouse model of recessive dystrophic epidermolysis bullosa(LIPPINCOTT WILLIAMS & WILKINS, 2022) Schmidt, Daniela; Díaz Céspedes, Paula Estefany; Muñoz, Daniela; Espinoza Mihovilovic, Fernanda Mileva; Nystrom, Alexander; Fuentes, Ignacia; Ezquer, Marcelo; Bennett, David L.; Calvo Bascuñán, MargaritaRecessive dystrophic epidermolysis bullosa (RDEB) is a rare genetic condition in which mutations in the type VII collagen gene (COL7A1) lead to decreased expression of this anchoring protein of the skin, causing the loss of stability at the dermo-epidermal junction. Most patients with RDEB experience neuropathic pain and itch due to the development of a small fibre neuropathy, characterised by decreased intraepidermal innervation and thermal hypoaesthesia. To understand the physiopathology of this neuropathy, we used a mouse model of RDEB (Col7a1(flNeo/flNeo)) and performed a detailed characterisation of the somatosensory system. Col7a1(flNeo/flNeo) mice showed a decrease in heat sensitivity, an increase in spontaneous scratching, and a significant decrease in intraepidermal nerve fibre density in the hindpaw; these changes were distal because there was no significant loss of unmyelinated or myelinated fibres in the nerve trunk. Of interest, we observed a decrease in axon diameter in both myelinated and unmyelinated fibres. This axonal damage was not associated with inflammation of the dorsal root ganglion or central projection targets at the time of assessment. These results suggest that in RDEB, there is a distal degeneration of axons produced by exclusive damage of small fibres in the epidermis, and in contrast with traumatic and acute neuropathies, it does not induce sustained neuroinflammation. Thus, this animal model emphasizes the importance of a healthy cutaneous environment for maintenance of epidermal innervation and faithfully replicates the pathology in humans, offering the opportunity to use this model in the development of treatments for pain for patients with RDEB.
- ItemEpidemiology of epidermolysis bullosa in Chile(2024) Palisson, Francis; Yubero, Maria Joao; Lecaros, Cristobal; Kramer, Susanne; Fuentes, Constanza; Morande, Pilar; Noya, Belkis; Cofre, Glenda; Castillo, Jimena; Acevedo, Francisco; Burattini, Natalia; Munoz, Antonella; Klausseger, Alfred; Fuentes, IgnaciaIn this manuscript we are presenting the first National Epidermolysis Bullosa Epidemiology study done in South America. Our manuscript describes not only population-level estimates, such as incidence, prevalence and mortality of EB, but also genetic data that are unique to this underrepresented population. We report new data about this rare disease showing comparable life expectancy to wealthier nations, demonstrating the value of specialized EB care centres.
- ItemEpithelial HMGB1 Delays Skin Wound Healing and Drives Tumor Initiation by Priming Neutrophils for NET Formation(2019) Hoste, Esther; Maueroder, Christian; van Hove, Lisette; Catrysse, Leen; Vikkula, Hanna-Kaisa; Sze, Mozes; Maes, Bastiaan; Karjosukarso, Dyah; Martens, Liesbet; Goncalves, Amanda; Parthoens, Eef; Roelandt, Ria; Declercq, Wim; Fuentes, Ignacia; Palisson, Francis; Gonzalez, Sergio; Salas-Alanis, Julio C.; Boon, Louis; Huebener, Peter; Mulder, Klaas Willem; Ravichandran, Kodi; Saeys, Yvan; Schwabe, Robert Felix; van Loo, GeertRegenerative responses predispose tissues to tumor formation by largely unknown mechanisms. High-mobility group box 1 (HMGB1) is a danger-associated molecular pattern contributing to inflammatory pathologies. We show that HMGB1 derived from keratinocytes, but not myeloid cells, delays cutaneous wound healing and drives tumor formation. In wounds of mice lacking HMGB1 selectively in keratinocytes, a marked reduction in neutrophil extracellular trap (NET) formation is observed. Pharmacological targeting of HMGB1 or NETs prevents skin tumorigenesis and accelerates wound regeneration. HMGB1-dependent NET formation and skin tumorigenesis is orchestrated by tumor necrosis factor (TNF) and requires RIPK1 kinase activity. NETs are present in the microenvironment of keratinocyte-derived tumors in mice and lesional and tumor skin of patients suffering from recessive dystrophic epidermolysis bullosa, a disease in which skin blistering predisposes to tumorigenesis. We conclude that tumorigenicity of the wound microenvironment depends on epithelial-derived HMGB1 regulating NET formation, thereby establishing a mechanism linking reparative inflammation to tumor initiation.
- ItemLongitudinal study of wound healing status and bacterial colonisation of Staphylococcus aureus and Corynebacterium diphtheriae in epidermolysis bullosa patients(2022) Fuentes, Ignacia; Yubero, María Joao; Morandé, Pilar; Varela, Carmen; Oróstica, Karen; Acevedo, Francisco; Rebolledo‐Jaramillo, Boris; Arancibia, Esteban; Porte, Lorena; Palisson, FrancisEpidermolysis bullosa (EB) is an inherited disorder characterised by skin fragility and the appearance of blisters and wounds. Patient wounds are often colonised or infected with bacteria, leading to impaired healing, pain and high risk of death by sepsis. Little is known about the impact of bacterial composition and susceptibility in wound resolution, and there is a need for longitudinal studies to understand healing outcomes with different types of bacterial colonisation. A prospective longitudinal study of 70 wounds from 15 severe EB patients (Junctional and Recessive Dystrophic EB) from Chile. Wounds were selected independently of their infected status. Wound cultures, including bacterial species identification, composition and Staphylococcus aureus (SA) antibiotic susceptibility were registered. Wounds were separated into categories according to their healing capacity, recognising chronic, and healing wounds. Hundred-one of the 102 wound cultures were positive for bacterial growth. From these, 100 were SA-positive; 31 were resistant to Ciprofloxacin (31%) and only seven were methicillin-resistant SA (7%). Ciprofloxacin-resistant SA was found significantly predominant in chronic wounds (**P < .01). Interestingly, atoxigenic Corynebacterium diphtheriae (CD) was identified and found to be the second most abundant recovered bacteria (31/101), present almost always in combination with SA (30/31). CD was only found in Recessive Dystrophic EB patients and not related to wound chronicity. Other less frequent bacterial species found included Pseudomonas aeruginosa, Streptococus spp. and Proteus spp. Infection was negatively associated with the healing status of wounds.
- ItemMaintenance of chronicity signatures in fibroblasts isolated from recessive dystrophic epidermolysis bullosa chronic wound dressings under culture conditions(2023) De Gregorio, Cristian; Catalán, Evelyng; Garrido, Gabriel; Morandé, Pilar; Bennett, Jimena C.; Muñoz, Catalina; Cofré, Glenda; Huang, Ya-Lin; Cuadra, Bárbara; Murgas, Paola; Calvo Bascuñan, Margarita; Altermatt Couratier, Fernando René; Yubero, María J.; Palisson, Francis; South, Andrew P.; Ezquer, Marcelo; Fuentes, IgnaciaBackground Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a rare inherited skin disease caused by variants in the COL7A1 gene, coding for type VII collagen (C7), an important component of anchoring fibrils in the basement membrane of the epidermis. RDEB patients suffer from skin fragility starting with blister formation and evolving into chronic wounds, inflammation and skin fibrosis, with a high risk of developing aggressive skin carcinomas. Restricted therapeutic options are limited by the lack of in vitro models of defective wound healing in RDEB patients. Results In order to explore a more efficient, non-invasive in vitro model for RDEB studies, we obtained patient fibroblasts derived from discarded dressings) and examined their phenotypic features compared with fibroblasts derived from non-injured skin of RDEB and healthy-donor skin biopsies. Our results demonstrate that fibroblasts derived from RDEB chronic wounds (RDEB-CW) displayed characteristics of senescent cells, increased myofibroblast differentiation, and augmented levels of TGF-β1 signaling components compared to fibroblasts derived from RDEB acute wounds and unaffected RDEB skin as well as skin from healthy-donors. Furthermore, RDEB-CW fibroblasts exhibited an increased pattern of inflammatory cytokine secretion (IL-1β and IL-6) when compared with RDEB and control fibroblasts. Interestingly, these aberrant patterns were found specifically in RDEB-CW fibroblasts independent of the culturing method, since fibroblasts obtained from dressing of acute wounds displayed a phenotype more similar to fibroblasts obtained from RDEB normal skin biopsies. Conclusions Our results show that in vitro cultured RDEB-CW fibroblasts maintain distinctive cellular and molecular characteristics resembling the inflammatory and fibrotic microenvironment observed in RDEB patients’ chronic wounds. This work describes a novel, non-invasive and painless strategy to obtain human fibroblasts chronically subjected to an inflammatory and fibrotic environment, supporting their use as an accessible model for in vitro studies of RDEB wound healing pathogenesis. As such, this approach is well suited to testing new therapeutic strategies under controlled laboratory conditions.
- ItemOrofacial Anomalies in Kindler Epidermolysis Bullosa(2024) Kraemer, Susanne; Hillebrecht, Anna Lena; Wang, Yao; Badea, Mihail-Alexandru; Barrios, Jose Ignacio; Danescu, Sorina; Fuentes, Ignacia; Kartal, Demet; Klausegger, Alfred; Ponce de Leon, Enrique; Schilke, Reinhard; Yordanova, Ivelina; Bloch-Zupan, Agnes; Has, CristinaImportanceKindler epidermolysis bullosa is a genetic skin-blistering disease associated with recessive inherited pathogenic variants in FERMT1, which encodes kindlin-1. Severe orofacial manifestations of Kindler epidermolysis bullosa, including early oral squamous cell carcinoma, have been reported. ObjectiveTo determine whether hypoplastic pitted amelogenesis imperfecta is a feature of Kindler epidermolysis bullosa. Design, Settings, and ParticipantsThis longitudinal, 2-center cohort study was performed from 2003 to 2023 at the Epidermolysis Bullosa Centre, University of Freiburg, Germany, and the Special Care Dentistry Clinic, University of Chile in association with DEBRA Chile. Participants included a convenience sampling of all patients with a diagnosis of Kindler epidermolysis bullosa. Main Outcomes and MeasuresThe primary outcomes were the presence of hypoplastic pitted amelogenesis imperfecta, intraoral wounds, gingivitis and periodontal disease, gingival hyperplasia, vestibular obliteration, cheilitis, angular cheilitis, chronic lip wounds, microstomia, and oral squamous cell carcinoma. ResultsThe cohort consisted of 36 patients (15 female [42%] and 21 male [58%]; mean age at first examination, 23 years [range, 2 weeks to 70 years]) with Kindler epidermolysis bullosa. The follow-up ranged from 1 to 24 years. The enamel structure was assessed in 11 patients, all of whom presented with enamel structure abnormalities. The severity of hypoplastic pitted amelogenesis imperfecta varied from generalized to localized pitting. Additional orofacial features observed include gingivitis and periodontal disease, which was present in 90% (27 of 30 patients) of those assessed, followed by intraoral lesions (16 of 22 patients [73%]), angular cheilitis (24 of 33 patients [73%]), cheilitis (22 of 34 patients [65%]), gingival overgrowth (17 of 26 patients [65%]), microstomia (14 of 25 patients [56%]), and vestibular obliteration (8 of 16 patients [50%]). Other features included chronic lip ulcers (2 patients) and oral squamous cell carcinoma with lethal outcome (2 patients). Conclusions and RelevanceThese findings suggest that hypoplastic pitted amelogenesis imperfecta is a feature of Kindler epidermolysis bullosa and underscore the extent and severity of oral manifestations in Kindler epidermolysis bullosa and the need for early and sustained dental care.
- ItemRecessive dystrophic epidermolysis bullosa results in painful small fibre neuropathy(2017) Von Bischhoffshausen, Sofia; Ivulic, Dinka; Alvarez, Paola; Schuffeneger, Victor C.; Idiaquez, Juan; Fuentes, Constanza; Morandé, Pilar; Fuentes, Ignacia; Palisson, Francis; Calvo Bascuñan, Margarita; Bennet, David L. H.
- ItemSkin in the game: a review of single-cell and spatial transcriptomics in dermatological research(2024) Schepps, Samuel; Xu, Jonathan; Yang, Henry; Mandel, Jenna; Mehta, Jaanvi; Tolotta, Julianna; Baker, Nicole; Tekmen, Volkan; Nikbakht, Neda; Fortina, Paolo; Fuentes, Ignacia; Lafleur, Bonnie; Cho, Raymond J.; South, Andrew P.Single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) are two emerging research technologies that uniquely characterize gene expression microenvironments on a cellular or subcellular level. The skin, a clinically accessible tissue composed of diverse, essential cell populations, serves as an ideal target for these high-resolution investigative approaches. Using these tools, researchers are assembling a compendium of data and discoveries in healthy skin as well as a range of dermatologic pathophysiologies, including atopic dermatitis, psoriasis, and cutaneous malignancies. The ongoing advancement of single-cell approaches, coupled with anticipated decreases in cost with increased adoption, will reshape dermatologic research, profoundly influencing disease characterization, prognosis, and ultimately clinical practice.