| 1. |
- Bankell, Elisabeth, et al.
(author)
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LL-37-induced caspase-independent apoptosis is associated with plasma membrane permeabilization in human osteoblast-like cells
- 2021
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In: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 135
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Journal article (peer-reviewed)abstract
- The host defense peptide LL-37 is active against both gram-positive and gram-negative bacteria, but it has also been shown to reduce human host cell viability. However, the mechanisms behind LL-37-induced human host cell cytotoxicity are not yet fully understood. Here, we assess if LL-37-evoked attenuation of human osteoblast-like MG63 cell viability is associated with apoptosis, and if the underlying mechanism may involve LL-37-induced plasma membrane permeabilization. MG63 cell viability and plasma membrane permeabilization were investigated by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and by measuring lactate dehydrogenase (LDH) release, respectively. Apoptosis was assessed by the terminal deoxynucleotidyl dUTP nick end labeling (TUNEL) assay and Annexin V flow cytometry, and caspase-3 and poly (ADP-ribose) polymerase (PARP) cleavage were determined by Western blot. LL-37 (4 and 10 μM) reduced both cell number and cell viability, and these effects were associated with a pro-apoptotic effect demonstrated by positive TUNEL staining and Annexin V flow cytometry. LL-37-induced apoptosis was not coupled to either caspase-3 or PARP cleavage, suggesting that LL-37 causes caspase-independent apoptosis in MG63 cells. Both LL-37 and the well-known plasma membrane permeabilizer Triton X-100 reduced cell viability and stimulated LDH release. Triton X-100-treated cells showed positive TUNEL staining, and the detergent accumulated cells in late apoptosis/necrosis. Similar to LL-37, Triton X-100 caused no PARP cleavage. We conclude that LL-37 promotes caspase-independent apoptosis, and that this effect seems coupled to plasma membrane permeabilization in human MG63 cells.
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| 2. |
- Dahl, Sara, et al.
(author)
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The host defense peptide LL-37 triggers release of nucleic acids from human mast cells
- 2018
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In: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 109, s. 39-45
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Journal article (peer-reviewed)abstract
- The human host defense peptide LL-37 possesses antimicrobial activity but also affects host cell function and viability. Mast cells are involved in innate immunity but no data have been presented on effects of LL-37 on human mast cell viability and export of nucleic acids. Here, we demonstrated by immunofluorescence microscopy that synthesized LL-37 was internalized by human LAD2 mast cells and detected both in cytoplasm and nucleus. Treatment with high (4 and 10 μM) but not low (1 μM) concentrations of LL-37 for 4 h reduced cell viability assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Stimulation with 10 μM LL-37 for 4 h enhanced export of nucleic acids, total protein and lactate dehydrogenase (LDH), suggesting that both nuclear and plasma membranes are permeabilized by LL-37. Although LL-37 triggered release of nucleic acids, no extracellular trap-like structures were observed by laser scanning confocal microscopy of cells incubated with the plasma membrane impermeable nucleic acid fluorophore SYTOX-Green, indicating that LL-37 promotes export of nucleic acids but not formation of extracellular traps. On the other hand, phorbol-12-myristate-13-acetate (PMA), which is a well-known inducer of extracellular traps, stimulated export of nucleic acids and also formation of extracellular trap-like structures. However, PMA had no effect on export of either total protein or LDH. Hence, LL-37 and PMA seem to stimulate export of nucleic acids from LAD2 mast cells through different pathways. In conclusion, we demonstrate that LL-37 triggers release of nucleic acids from human mast cells but not the formation of extracellular trap-like structures.
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| 3. |
- Svensson, Daniel, et al.
(author)
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Inhibition of MicroRNA-125a Promotes Human Endothelial Cell Proliferation and Viability through an Antiapoptotic Mechanism.
- 2014
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In: Journal of Vascular Research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 51:3, s. 239-245
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Journal article (peer-reviewed)abstract
- The microRNA-125a (miR-125a) is highly expressed in endothelial cells, but its role in vascular biology is not known. Endothelial cell proliferation and viability play an important role in endothelial healing, and we hypothesize that miR-125a regulates this process. The aim of the present study was to investigate if miR-125a controls human endothelial cell proliferation, viability and endothelial healing, and to assess the mechanisms involved. We showed that overexpression of miR-125a by transfection with miR-125a mimic reduced human umbilical vein endothelial cell (HUVEC) proliferation and viability, and stimulated apoptosis as demonstrated by a miR-125a-induced increase of the proportion of annexin V-positive cells monitored by flow cytometry. Moreover, we showed that the miR-125a mimic downregulated the antiapoptotic Bcl2 protein and upregulated caspase 3, suggesting that these two proteins represent molecular targets for miR-125a. Accordingly, transfection with miR-125a inhibitor, downregulating miR-125a expression, promoted HUVEC proliferation and viability, and reduced apoptosis. Importantly, transfection with miR-125a inhibitor promoted HUVEC tube formation in Matrigel, suggesting that reduction of miR-125a has a proangiogenic effect. In conclusion, downregulation of miR-125a through local transfection with miR-125a inhibitor might be a new way to enhance endothelial cell proliferation and viability, thereby promoting the reendothelialization observed in response to intimal injury. © 2014 S. Karger AG, Basel.
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| 4. |
- Säll, Johanna, et al.
(author)
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The antimicrobial peptide LL-37 alters human osteoblast Ca2+ handling and induces Ca2+-independent apoptosis
- 2013
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In: Journal of Innate Immunity. - : S. Karger. - 1662-811X .- 1662-8128. ; 3:5, s. 290-300
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Journal article (peer-reviewed)abstract
- The human antimicrobial peptide cathelicidin LL-37 has, besides its antimicrobial properties, also been shown to regulate apoptosis in a cell type-specific manner. Mechanisms involved in LL-37-regulated apoptotic signaling are not identified. Here, we show that LL-37 reduces the human osteoblast-like MG63 cell number and cell viability in the micromolar concentration range with an IC50 value of about 5 µM. Treatment with 4 µM LL-37 increased the number of annexin V-positive cells and stimulated activation of caspase 3 showing that LL-37 promotes apoptosis. Treatment with 4 µM LL-37 caused an acute and sustained rise in intracellular Ca(2+) concentration assessed by laser-scanning confocal microscopy of Fluo-4-AM-loaded MG63 cells. LL-37 increased Ca(2+) also in the presence of the respective L- and T-type voltage-sensitive Ca(2+) channel blockers nifedipine and NiCl2. LL-37 had no effect on Ca(2+) in cells incubated with Ca(2+)-free solution. LL-37 (4 and 8 µM) reduced the MG63 cell number both in the presence and absence of Ca(2+) in the medium. In conclusion, LL-37 reduces the osteoblast cell number by promoting apoptosis, and furthermore, LL-37 stimulates Ca(2+) inflow via a mechanism independent of voltage-sensitive Ca(2+) channels. Interestingly, LL-37-induced lowering of the cell number seems to be mediated via a mechanism independent of Ca(2+).
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| 5. |
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| 6. |
- Badhai, Jitendra, et al.
(author)
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Differential expression of RPS19 5’UTR variants implicated in Diamond-Blackfan anemia
- 2012
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Other publication (other academic/artistic)abstract
- Heterozygous mutations in the ribosomal protein (RP) S19 gene RPS19 are found in about 25% of patients with the congenital erythroblastopenia Diamond-Blackfan anemia (DBA). The RPS19 gene encodes a single RPS19 isoform from three known transcriptional start sites (TSS) with different 5’ untranslated region (UTR). The regulation of RPS19 expression is poorly understood as well as the significance of different 5’UTRs. A few rare sequence variants within the 5’UTR have also been reported in patients with DBA. We determined the transcriptional start sites (TSS) and the tissue distribution of variant 5’UTRs of RPS19. Twenty-nine novel TSS in K562 cells and testis were identified. We then analyzed the relative proportion of three selected 5’UTRs of different length on a panel of primary tissues. The shorter 5’UTR were most abundant in all tissues but with large variations in relative levels of shorter versus longer transcripts. To clarify the effect of different RPS19 5’UTRs on translation we designed and expressed constructs using three 5’UTRs of different length. The short 5’UTR(+35nt.) translate 4-6 folds more efficiently than the two longer variants with 5’UTRs of 382nt. and 467nt., respectively We also introduced DBA associated insertion (c.-149_-148insGCCA, c.-149_-148insAGCC ) and deletion (c.-144_-141delTTTC) variants in the 5’UTR. . Interestingly, the DBA associated 5’UTR sequence variants showed a 20-30% reduction in RPS19 levels when compared to the corresponding w.t. constructs. Our results indicate that the RPS19 gene has a broad range of TSS with tissue specific variations. We also show that sequence variants in the 5’UTR in some DBA patients reduce RPS19 expression with implications for the pathophysiology of the disease.
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| 7. |
- Celik, Selvi, et al.
(author)
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Antisense regulation of atrial natriuretic peptide expression
- 2019
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In: JCI Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 4:19
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Journal article (peer-reviewed)abstract
- The cardiac hormone atrial natriuretic peptide (ANP) is a central regulator of blood volume and a therapeutic target in hypertension and heart failure. Enhanced ANP activity in such conditions through inhibition of the degradative enzyme neprilysin has shown clinical efficacy but is complicated by consequences of simultaneous accumulation of a heterogeneous array of other hormones. Targets for specific ANP enhancement have not been available. Here, we describe a cis-acting antisense transcript (NPPA-AS1), which negatively regulates ANP expression in human cardiomyocytes. We show that NPPA-AS1 regulates ANP expression via facilitating NPPA repressor RE1-silencing transcription factor (REST) binding to its promoter, rather than forming an RNA duplex with ANP mRNA. Expression of ANP mRNA and NPPA-AS1 was increased and correlated in isolated strained human cardiomyocytes and in hearts from patients with advanced heart failure. Further, inhibition of NPPA-AS1 in vitro and in vivo resulted in increased myocardial expression of ANP, increased circulating ANP, increased renal cGMP, and lower blood pressure. The effects of NPPA-AS1 inhibition on NPPA expression in human cardiomyocytes were further marked under cell-strain conditions. Collectively, these results implicate the antisense transcript NPPA-AS1 as part of a physiologic self-regulatory ANP circuit and a viable target for specific ANP augmentation.
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| 8. |
- Celik, Selvi, et al.
(author)
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Extracellular Vesicle-Associated TWEAK Contributes to Vascular Inflammation and Remodeling During Acute Cellular Rejection
- 2023
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In: JACC: Basic to Translational Science. - : Elsevier BV. - 2452-302X. ; 8:5, s. 439-456
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Journal article (peer-reviewed)abstract
- Acute cellular rejection (ACR) is a leading cause of graft loss and death after heart transplantation despite effective immunosuppressive therapies. The identification of factors that impair graft vascular barrier function or promote immune cell recruitment during ACR could provide new therapeutic opportunities for the treatment of patients who receive transplants. In 2 ACR cohorts, we found the extracellular vesicle-associated cytokine TWEAK to be elevated during ACR. Vesicular TWEAK promoted expression of proinflammatory genes and the release of chemoattractant cytokines from human cardiac endothelial cells. We conclude that vesicular TWEAK is a novel target with potential therapeutic implications in ACR.
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| 9. |
- Celik, Selvi, et al.
(author)
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Functional Screening Identifies MicroRNA Regulators of Corin Activity and Atrial Natriuretic Peptide Biogenesis
- 2019
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In: Molecular and Cellular Biology. - 0270-7306. ; 39:23
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Journal article (peer-reviewed)abstract
- Atrial natriuretic peptide (ANP) represents an attractive therapeutic target in hypertension and heart failure. The biologically active form of ANP is produced by the cardiac serine protease corin, and modulation of its activity might therefore represent a novel approach for ANP augmentation. MicroRNAs (miRNAs) are pervasive regulators of gene expression, but their potential role in regulating corin activity has not been elucidated. Our aim was to systematically identify and characterize miRNA regulators of corin activity in human cardiomyocytes. An assay for measuring serine protease activity in human induced pluripotent stem cell (iPS)-derived cardiomyocytes was used to perform a comprehensive screening of miRNA family inhibitors (n = 42). miRNA 1-3p (miR-1-3p) was identified as a potent inhibitor of corin activity. The interaction between miR-1-3p and a specific target site in the CORIN 3' untranslated region (3' UTR) was confirmed through argonaute 2 (AGO2)-RNA immunoprecipitation and reporter assays. Inhibition of miR-1-3p resulted in upregulation of CORIN gene and protein expression, as well as a concomitant increase in extracellular ANP. Additionally, miR-1-3p was found to interact with and inhibit the expression of several transcriptional activators of ANP gene expression. In conclusion, we have identified a novel regulator of corin activity and ANP biogenesis in human cardiomyocytes that might be of potential future therapeutic utility.
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| 10. |
- Devaux, Yvan, et al.
(author)
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Association of circulating MicroRNA-124-3p levels with outcomes after out-of-hospital cardiac arrest : A substudy of a randomized clinical trial
- 2016
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In: JAMA Cardiology. - : American Medical Association (AMA). - 2380-6583. ; 1:3, s. 305-313
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Journal article (peer-reviewed)abstract
- IMPORTANCE: The value of microRNAs (miRNAs) as biomarkers has been investigated in various clinical contexts. Initial small-scale studies suggested that miRNAs might be useful indicators of outcome after cardiac arrest. OBJECTIVE: To address the prognostic value of circulating miRNAs in a large cohort of comatose patients with out-of-hospital cardiac arrest. DESIGN, SETTING, AND PARTICIPANTS: This substudy of the Target Temperature Management After Cardiac Arrest (TTM) trial, a multicenter randomized, parallel-group, assessor-blinded clinical trial, compared the 6-month neurologic outcomes and survival of patients with cardiac arrest after targeted temperature management at 33°C or 36°C. Five hundred seventy-nine patients who survived the first 24 hours after the return of spontaneous circulation and who had blood samples available for miRNA assessment were enrolled from 29 intensive care units in 9 countries from November 11, 2010, to January 10, 2013. Final follow-up was completed on July 3, 2013, and data were assessed from February 1, 2014, to February 1, 2016. INTERVENTIONS: Blood sampling at 48 hours after the return of spontaneous circulation. MAINOUTCOMES AND MEASURES: The primary end point was poor neurologic outcomeat6 months (cerebral performance category score, 3 [severe neurologic sequelae], 4 [coma], or 5 [death]). The secondary end point was survival until the end of the trial. Circulating levels of miRNAs were measured by sequencing and polymerase chain reaction. RESULTS: Of the 579 patients (265 men [80.3%]; mean [SD] age, 63 [12] years), 304 patients (52.5%) hada poor neurologic outcomeat 6months. Inthe discovery phase with short RNA sequencing in 50 patients, the brain-enriched miR-124-3p level was identified as a candidate prognostic variable for neurologic outcomes. In the validation cohort of 529 patients, mean (SD) levels of miR-124-3p were higher in patients with a poor outcome (8408 [12 465] copies/μL) compared with patients with a good outcome (1842 [3025] copies/μL; P < .001). The miR-124-3p level was significantly associated with neurologic outcomes in the univariable analysis (odds ratio, 6.72; 95% CI, 4.53-9.97). In multivariable analyses using logistic regression, miR-124-3p levels were independently associated with neurologic outcomes (odds ratio, 1.62; 95% CI, 1.13-2.32). In Cox proportional hazards models, higher levels of miR-124-3p were significantly associated with lower survival (hazard ratio, 1.63; 95% CI, 1.37-1.93). CONCLUSIONS AND RELEVANCE: Levels of miR-124-3p can be used as prognostication tools for neurologic outcome and survival after out-of-hospital cardiac arrest. Thus, miRNA levels may aid in tailoring health care for patients with cardiac arrest.
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