Project description:Renal tubular epithelial cells (TECs) are critical mediators of renal fibrogenesis. Telomere dysfunction has been associated with renal injury and fibrosis. However, the role of telomere dysfunction specifically in TECs in the onset and progression of renal fibrosis remains poorly understood. To investigate the impact of telomere dysfunction on renal injury and fibrosis, we generated mice depleted for the shelterin component TRF1 specifically in TECs. Genetic ablation of Trf1 caused decline in renal function, tubular injury and tubulointerstitial fibrosis eight weeks after TRF1 depletion, concomitant with excessive accumulation of extracellular matrix (ECM), cell cycle arrest at G2/M phase, and telomeric damage. Trf1Δ/Δ mice activated regenerative repair mechanism, increasing the risk of of chronic kidney disease (CKD) progression following acute kidney injury (AKI), supporting proliferation-mediated telomere shortening in tubular cells. Mechanistically, Trf1 deletion upregulated Ras–Raf–Mek–Erk, PI3k/Akt/mTOR and p38 pathways. At humane endpoint, Trf1Δ/Δ mice displayed elevated urinary albumin-to-creatinine ratio (uACR), associated with augmented interstitial fibrosis and tubular atrophy eventually leading to CKD. In folic acid (FA)-induced nephropathy, depletion of Trf1 in TECs mitigated the fibrogenic phenotype of CKD. Collectively, our study underlies the important role of TECs in the development and progression of renal fibrosis and CKD associated to dysfunctional telomeres.
Project description:We used microarrays to analyze the prevalence of signalling induced by acute telomere dysfunction (as induced by TRF2DBDM expression = Dataset 1) and in TERC- compared to TERC+ HCC (Dataset 2). Keywords: acute telomere dysfunction, hepatocellular cancer
Project description:The study comprises various components: Samples TD: We aims to screen out different gene expression profile in donor biopsies after revascularization , We aims to predict renal allograft dysfunction early after transplantation. Samples AR, ATN, Tx: We aim to screen out different gene expression profile in acute rejection on the kidney. We aim to screen out different gene expression profile in acute tubular necrosis on the kidney. Results from the various study components can help to diagnose renal allograft dysfunction with different causes by distinct gene expression profile. Keywords: acute rejection, acute tubular necrosis, donor biopsies, renal allograft dysfunction Samples AR1-AR17: This study has been accomplished with 17 patients of acute rejection on the kidney.Technical replicates: 2 replicates Samples ATN1-ATN5: This study has been accomplished with 5 patients of acute tubular necrosis on the kidney. Technical replicates: 2 replicates Samples Tx1-Tx14: This study has been accomplished with 14 patients of stable renal function on the kidney.Tecnical replicates:2 replicates(except Tx12) Samples TD1-TD12: This study has been accomplished with 12 patients of donor tissue with stable function early after transplantation on the kidney.Technical replicates: 2 replicates Samples TD13-TD21: This study has been accomplished with 9 patients of donor tissue with renal dysfunction early after transplantation on the kidney.Technical replicates: 2 replicates
Project description:Tubulointerstitial fibrosis associated to chronic kidney disease represents a global healthcare problem. We showed previously that short and dysfunctional telomeres lead to interstitial renal fibrosis, however, the cell-of-origin of kidney fibrosis associated to telomere dysfunction was unknown to date. To identify the specific cell type responsible for this type of renal fibrosis, we induced telomere dysfunction by deleting the Trf1 telomere-binding factor both in renal fibroblasts and pericytes both in short-term and long-term life-long experiments in mice. Short-term Trf1 deletion in renal fibroblasts and pericytes was not sufficient to trigger kidney fibrosis. However, long-term persistent deletion of Trf1 in fibroblasts, triggered inflammation, cell cycle arrest, fibrogenesis, and vascular rarefaction. These cellular responses lead to macrophage-to-myofibroblast transition (MMT), Endothelial-to-mesenchymal transition (EndMT), and epithelial-to-mesenchymal transition (EMT), ultimately causing kidney fibrosis at humane-endpoint when deletion of Trf1 in fibroblasts was maintained throughout the lifespan of mice. In contrast, Trf1 deletion in pericytes did not lead to any kidney phenotypes both in short-term and long-term experiments.
Project description:Background and Aims: Telomere dysfunction can increase tumor initiation by induction of chromosomal instability, but initiated tumor cells need to reactivate telomerase for genome stabilization and tumor progression. However, this concept has not been proven in vivo since appropriate mouse models were lacking. Here, we analyzed hepatocarcinogenesis (i) in a novel mouse model of inducible telomere dysfunction on a telomerase-proficient background, (ii) in telomerase knockout mice with chronic telomere dysfunction (G3 mTerc-/-), and (iii) in wild-type mice with functional telomeres and telomerase. Transient or chronic telomere dysfunction enhanced the rates of chromosomal aberrations during hepatocarcinogenesis, but only telomerase-proficient mice exhibited significantly increased rates of macroscopic tumor formation and cancer cell proliferation in response to telomere dysfunction. In contrast, telomere dysfunction resulted in pronounced accumulation of DNA damage, cell cycle arrest and apoptosis in telomerase-deficient liver tumors. Together, these data provide the first in vivo evidence that transient telomere dysfunction during early and late stages of tumorigenesis can promote chromosomal instability and carcinogenesis in telomerase-proficient mice in the absence of additional genetic checkpoint defects at germline level. RNA from liver tumors derived from from DEN treated TTD+ mice TTD- mice and RNA from normal liver 48h-72h after doxycycline induced transient telomere dysfunction in TTD+ and TTD- liver were isolated and RNA was extracted. Agilent Mouse 4x44K v2 arrays were used. DNA from liver tumors and corrresponding kidney as control derived from from DEN treated TTD+ mice, TTD- mice and mTERC-/- G3 mice was isolated and extracted using Phenol/Chloroform. Agilent Mouse 4x44K and Mouse 1x244K arrays were used.
Project description:We performed single-molecule telomere length and telomere fusion analysis in patients at different stages of chronic lymphocytic leukaemia (CLL). Our work identified the shortest telomeres ever recorded in primary human tissue reinforcing the concept that there is significant cell division in CLL. Furthermore, we provide direct evidence that critical telomere shortening, dysfunction and fusion contribute to disease progression. The frequency of short telomeres and fusion events increased with advanced disease, but importantly these were also found in a subset of early-stage patient samples indicating that these events can precede disease progression. Sequence analysis of fusion events isolated from individuals with the shortest telomeres revealed limited numbers of repeats at the breakpoint, sub-telomeric deletion and microhomology. Array-CGH analysis of individuals displaying evidence of telomere dysfunction revealed large-scale genomic rearrangements that were concentrated in the telomeric regions; this was not observed in samples with longer telomeres. Array CGH was undertaken on six individuals (five CLL stage C and one stage A) that displayed evidence of telomere dysfunction, and four (three CLL stage A and one stage B) that displayed longer and apparently stable telomeres.
Project description:The study comprises various components: Samples TD: We aims to screen out different gene expression profile in donor biopsies after revascularization , We aims to predict renal allograft dysfunction early after transplantation. Samples AR, ATN, Tx: We aim to screen out different gene expression profile in acute rejection on the kidney. We aim to screen out different gene expression profile in acute tubular necrosis on the kidney. Results from the various study components can help to diagnose renal allograft dysfunction with different causes by distinct gene expression profile. Keywords: acute rejection, acute tubular necrosis, donor biopsies, renal allograft dysfunction
Project description:Inflammatory bowel disease (IBD) is a challenging condition with limited therapeutic options. Inflammasome activation is integral to IBD pathogenesis, although the molecular instigators of its activation remain obscure. Here, we establish that telomere dysfunction activates the Yap1 transcriptional co-activator through pATM/c-Abl, which up-regulates expression of microbial receptors Nlrc4 and Nlrc5 and the cytokine pre-IL-18. Microbial engagement of these cytosolic receptors leads to production of mature IL-18, recruiting T cells and other immunocytes which secrete IFN-gamma to drive classical IBD pathology. Genotoxic stress per se (ionizing radiation) can also drive inflammasome activation. Alleviation of IBD pathology can be achieved via telomerase reactivation in intestinal epithelium, antibiotic treatment or pharmacological inhibition of Yap1 - reducing Nlrc4/5 expression as well as IL-18 and IFN-gamma production. Thus, telomere dysfunction-induced inflammasome activation identifies DNA damage signaling as a key instigator and promoter of IBD, illuminating potential novel therapeutic strategies for prevention and disease management.