Oral Ursodeoxycholic Acid Crosses the Blood Retinal Barrier in Patients with Retinal Detachment and Protects Against Retinal Degeneration in an Ex Vivo Model

AbstractRhegmatogenous retinal detachment (RD) is a threatening visual condition and a human disease model for retinal degenerations. Despite successful reattachment surgery, vision does not fully recover, due to subretinal fluid accumulation and subsequent photoreceptor cell death, through mechanisms that recapitulate those of retinal degenerative diseases. Hydrophilic bile acids are neuroprotective in animal models, but whether they can be used orally for retinal diseases is unknown. Ursodeoxycholic acid (UDCA) being approved for clinical use (e.g., in cholestasis), we have evaluated the ocular bioavailability of oral UDCA, administered to patients before RD surgery. The level of UDCA in ocular media correlated with the extent of blood retinal barrier disruption, evaluated by the extent of detachment and the albumin concentration in subretinal fluid. UDCA, at levels measured in ocular media, protected photoreceptors from apoptosis and necrosis in rat retinal explants, an ex vivo model of RD. The subretinal fluid from UDCA-treated patients, collected during surgery, significantly protected rat retinal explants from cell death, when compared to subretinal fluid from control patients. Pan-transcriptomic analysis of the retina showed that UDCA upregulated anti-apoptotic, anti-oxidant, and anti-inflammatory genes. Oral UDCA is a potential neuroprotective adjuvant therapy in RD and other retinal degenerative diseases and should be further evaluated in a clinical trial.

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Activation of Simultaneous Apoptosis and Necroptosis to Eradicate Drug Resistant Leukemia

Blood ◽

10.1182/blood.v126.23.1283.1283 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1283-1283

Author(s):

Scott McComb ◽

Julia Aguadé-Gorgorió ◽

Blerim Marovca ◽

Lena Harder ◽

Gunnar Cario ◽

...

Keyword(s):

Cell Death ◽

De Novo ◽

Conflicts Of Interest ◽

Ex Vivo ◽

Lymphoblastic Leukemia ◽

Short Circuit ◽

Large Set ◽

Ex Vivo Model ◽

Resistant Disease

Abstract Dysregulation of apoptotic pathways provides an indiscriminate mechanism for refractory acute lymphoblastic leukemia (ALL) to escape cell death induced by many chemotherapeutic compounds. Here we have assessed the potential of SMAC mimetic (SM) compounds to short circuit cell death resistance by blocking the pro-survival cellular inhibitor of apoptosis (cIAP) proteins. By screening a large set of patient-derived precursor B-cell ALL samples in an ex vivo model of the leukemia microenvironment we detect exquisite sensitivity to two different SM compounds, Birinapant and LCL161, in about one third of ALL samples. Strong ex vivo SM activity correlated with potent in vivo anti-leukemic efficacy against de novo refractory and relapsed ALL xenografts. Intriguingly, we find that although SM-sensitivity is independent of TNF and TNFR1 levels, expression of TNFR2 is highly predictive of response to SM in two separate cohorts of ALL samples, suggesting that TNFR2 expression may represent a promising biomarker for identifying SM-sensitive cells. Downstream, we employ a novel and powerful multi-colour Lenti-CRISPR approach to show that simultaneous disruption of both apoptotic and necroptotic genes is necessary to block SM-induced death. In contrast, disruption of RIP1 alone was adequate to block SM-induced apoptosis and necroptosis. Surprisingly, RIP1 loss had no significant impact on response to standard anti-leukemic therapies, supporting a view that the RIP1-dependent death pathway is not likely to be selected against in leukemia cells that have failed to respond to front line therapy. These results provide the first evidence that SM compounds can circumvent apoptotic escape in drug-refractory ALL through parallel activation of both RIP1-dependent apoptosis and necroptosis. Furthermore, our data strongly support further development of SM as anti-leukemic agents for treatment in resistant disease. Disclosures No relevant conflicts of interest to declare.

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Iron is neurotoxic in retinal detachment and transferrin confers neuroprotection

Science Advances ◽

10.1126/sciadv.aau9940 ◽

2019 ◽

Vol 5 (1) ◽

pp. eaau9940 ◽

Cited By ~ 8

Author(s):

Alejandra Daruich ◽

Quentin Le Rouzic ◽

Laurent Jonet ◽

Marie-Christine Naud ◽

Laura Kowalczuk ◽

...

Keyword(s):

Retinal Detachment ◽

Vision Loss ◽

Ex Vivo ◽

Pigment Epithelium ◽

Retinal Pigment ◽

Subretinal Fluid ◽

Predictive Marker ◽

Visual Recovery ◽

Neuroprotective Effects

In retinal detachment (RD), photoreceptor death and permanent vision loss are caused by neurosensory retina separating from the retinal pigment epithelium because of subretinal fluid (SRF), and successful surgical reattachment is not predictive of total visual recovery. As retinal iron overload exacerbates cell death in retinal diseases, we assessed iron as a predictive marker and therapeutic target for RD. In the vitreous and SRF from patients with RD, we measured increased iron and transferrin (TF) saturation that is correlated with poor visual recovery. In ex vivo and in vivo RD models, iron induces immediate necrosis and delayed apoptosis. We demonstrate that TF decreases both apoptosis and necroptosis induced by RD, and using RNA sequencing, pathways mediating the neuroprotective effects of TF are identified. Since toxic iron accumulates in RD, we propose TF supplementation as an adjunctive therapy to surgery for improving the visual outcomes of patients with RD.

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Selective neuronal cell death in retinal degenerative diseases

Folia Pharmacologica Japonica ◽

10.1254/fpj.152.58 ◽

2018 ◽

Vol 152 (2) ◽

pp. 58-63

Author(s):

Kenji Sakamoto ◽

Asami Mori ◽

Kunio Ishii ◽

Tsutomu Nakahara

Keyword(s):

Cell Death ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Degenerative Diseases ◽

Retinal Degenerative Diseases

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IL-1 Family Members Mediate Cell Death, Inflammation and Angiogenesis in Retinal Degenerative Diseases

Frontiers in Immunology ◽

10.3389/fimmu.2019.01618 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 26

Author(s):

Yvette Wooff ◽

Si Ming Man ◽

Riemke Aggio-Bruce ◽

Riccardo Natoli ◽

Nilisha Fernando

Keyword(s):

Cell Death ◽

Family Members ◽

Degenerative Diseases ◽

Retinal Degenerative Diseases ◽

Mediate Cell

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Validation of organotypical hippocampal slice cultures as an ex vivo model of brain ischemia: different roles of NMDA receptors in cell death signalling after exposure to NMDA or oxygen and glucose deprivation

Cell and Tissue Research ◽

10.1007/s00441-011-1218-2 ◽

2011 ◽

Vol 345 (3) ◽

pp. 329-341 ◽

Cited By ~ 16

Author(s):

Hanna Ahlgren ◽

Kristi Henjum ◽

Ole Petter Ottersen ◽

Elise Rundén-Pran

Keyword(s):

Cell Death ◽

Nmda Receptors ◽

Brain Ischemia ◽

Hippocampal Slice ◽

Ex Vivo ◽

Glucose Deprivation ◽

Ex Vivo Model ◽

Oxygen And Glucose Deprivation ◽

Hippocampal Slice Cultures

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Extracellular vesicles and their miRNA cargo in retinal health and degeneration: mediators of homeostasis, and vehicles for targeted gene therapy

10.1101/2020.03.29.014910 ◽

2020 ◽

Cited By ~ 1

Author(s):

Yvette Wooff ◽

Adrian V. Cioanca ◽

Joshua A. Chu-Tan ◽

Riemke Aggio-Bruce ◽

Ulrike Schumann ◽

...

Keyword(s):

Gene Therapy ◽

Cell Death ◽

Immune Responses ◽

Oxidative Damage ◽

Extracellular Vesicles ◽

Immune Modulation ◽

Degenerative Diseases ◽

Retinal Degenerative Diseases ◽

Targeted Gene Therapy ◽

Small Rnaseq

1.1.AbstractPurposePhotoreceptor cell death and inflammation are known to occur progressively in retinal degenerative diseases, however the molecular mechanisms underlying these biological processes are largely unknown. Extracellular vesicles (EV) are essential mediators of cell-to-cell communication with emerging roles in the modulation of immune responses. EVs including exosomes encapsulate and transfer nucleic acids, including microRNA (miRNA), to recipient cells which in disease may result in dysfunctional immune responses and a loss of homeostatic regulation. In this work we investigated the role of isolated retinal small-medium sized EV (s-mEV) which includes exosomes in both the healthy and degenerating retina.MethodsIsolated s-mEV from normal retinas were characterized using dynamic light scattering, transmission electron microscopy and western blotting, and quantified across 5 days of photo-oxidative damage-induced degeneration using nanotracking analysis. Small RNAseq was used to characterize the miRNA cargo of retinal s-mEV isolated from healthy and damaged retinas. Finally, the effect of exosome inhibition on cell-to-cell miRNA transfer and immune modulation was conducted using systemic daily administration of exosome inhibitor GW4869 and in situ hybridization of s-mEV-abundant miRNA, miR-124-3p. Electroretinography and immunohistochemistry was performed to assess functional and morphological changes to the retina as a result of GW4869-induced exosome depletion.ResultsResults demonstrated an inverse correlation between s-mEV secretion and photoreceptor survivability, with a decrease in s-mEV numbers following degeneration. Small RNAseq revealed that s-mEVs contained uniquely enriched miRNAs in comparison to in whole retinal tissue however, there was no differential change in the s-mEV miRNAnome following photo-oxidative damage. Exosome inhibition via the use of GW4869 was also found to exacerbate retinal degeneration, with reduced retinal function and increased levels of inflammation and cell death demonstrated following photo-oxidative damage in exosome-inhibited mice. Further, GW4869-treated mice displayed impaired translocation of photoreceptor-derived miR-124-3p to the inner retina during damage.ConclusionsTaken together, we propose that retinal s-mEV and their miRNA cargo play an essential role in maintaining retinal homeostasis through immune-modulation, and have the potential to be used in targeted gene therapy for retinal degenerative diseases.

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