Project description:Rationale: Immunosuppression was associated with adverse events for patients with idiopathic pulmonary fibrosis (IPF) in the PANTHER-IPF (Evaluating the Effectiveness of Prednisone, Azathioprine and N-Acetylcysteine in Patients with IPF) clinical trial. The reason why some patients with IPF experience harm is unknown.Objectives: To determine whether age-adjusted leukocyte telomere length (LTL) was associated with the harmful effect of immunosuppression in patients with IPF.Methods: LTL was measured from available DNA samples from PANTHER-IPF (interim analysis, n = 79; final analysis, n = 118). Replication cohorts included ACE-IPF (Anticoagulant Effectiveness in Idiopathic Pulmonary Fibrosis) (n = 101) and an independent observational cohort (University of Texas Southwestern Medical Center-IPF, n = 170). LTL-stratified and medication-stratified survival analyses were performed using multivariable Cox regression models for composite endpoint-free survival.Measurements and Main Results: Of the subjects enrolled in the PANTHER-IPF and ACE-IPF, 62% (49/79) and 56% (28/50) had an LTL less than the 10th percentile of normal, respectively. In PANTHER-IPF, exposure to prednisone/azathioprine/N-acetylcysteine was associated with a higher composite endpoint of death, lung transplantation, hospitalization, or FVC decline for those with an LTL less than the 10th percentile (hazard ratio, 2.84; 95% confidence interval, 1.02-7.87; P = 0.045). This finding was replicated in the placebo arm of ACE-IPF for those exposed to immunosuppression (hazard ratio, 7.18; 95% confidence interval, 1.52-33.84; P = 0.013). A propensity-matched University of Texas Southwestern Medical Center IPF cohort showed a similar association between immunosuppression and composite endpoints (death, lung transplantation, or FVC decline) for those with an LTL less than the 10th percentile (hazard ratio, 3.79; 95% confidence interval, 1.73-8.30; P = 0.00085). An interaction was found between immunosuppression and LTL for the combined PANTHER-IPF and ACE-IPF clinical trials (Pinteraction = 0.048), and the University of Texas Southwestern Medical Center IPF cohort (Pinteraction = 0.00049).Conclusions: LTL is a biomarker that may identify patients with IPF at risk for poor outcomes when exposed to immunosuppression.
Project description:RationaleHeterozygous mutations in the coding regions of the telomerase genes, TERT and TERC, have been found in familial and sporadic cases of idiopathic interstitial pneumonia. All affected patients with mutations have short telomeres.ObjectivesTo test whether telomere shortening is a frequent mechanism underlying pulmonary fibrosis, we have characterized telomere lengths in subjects with familial or sporadic disease who do not have coding mutations in TERT or TERC.MethodsUsing a modified Southern blot assay, the telomerase restriction fragment length method, and a quantitative polymerase chain reaction assay we have measured telomere lengths of genomic DNA isolated from circulating leukocytes from normal control subjects and subjects with pulmonary fibrosis.Measurements and main resultsAll affected patients with telomerase mutations, including case subjects heterozygous for newly reported mutations in TERT, have short telomere lengths. A significantly higher proportion of probands with familial pulmonary fibrosis (24%) and sporadic case subjects (23%) in which no coding mutation in TERT or TERC was found had telomere lengths less than the 10th percentile when compared with control subjects (P = 2.6 x 10(-8)). Pulmonary fibrosis affectation status was significantly associated with telomerase restriction fragment lengths, even after controlling for age, sex, and ethnicity (P = 6.1 x 10(-11)). Overall, 25% of sporadic cases and 37% of familial cases of pulmonary fibrosis had telomere lengths less than the 10th percentile.ConclusionsA significant fraction of individuals with pulmonary fibrosis have short telomere lengths that cannot be explained by coding mutations in telomerase. Telomere shortening of circulating leukocytes may be a marker for an increased predisposition toward the development of this age-associated disease.
Project description:Idiopathic pulmonary fibrosis (IPF) occurs primarily in older adults and the incidence is clearly associated with aging. This disease seems to be associated with several hallmarks of aging, including telomere attrition and cellular senescence. Increasing evidence suggests that abnormalities involving telomeres and their proteome play a significant role in the pathobiology of IPF. The aim of this study is to summarize present knowledge in the field, as well as to discuss its possible clinical implications. Numerous mutations in genes associated with telomere functioning were studied in the context of IPF, mainly for Telomerase Reverse Transcriptase (TERT) and Telomerase RNA Component (TERC). Such mutations may lead to telomere shortening, which seems to increase the risk of IPF, negatively influence disease progression, and contribute to worse prognosis after lung transplantation. Some evidence indicates the possibility for the use of telomerase activators as potential therapeutic agents in pulmonary fibrosis. To sum up, increasing evidence suggests the role of telomere abnormalities in the pathobiology of IPF, natural history and prognosis of the disease. There are also possibilities for telomerase targeting in the potential development of new treatment agents. However, all these aspects require further research.
Project description:Exonic sequencing identified a family with idiopathic pulmonary fibrosis (IPF) containing a previously unreported heterozygous mutation in POT1 p.(L259S). The family displays short telomeres and genetic anticipation. We found that POT1(L259S) is defective in binding the telomeric overhang, nuclear accumulation, negative regulation of telomerase, and lagging strand maintenance. Patient cells containing the mutation display telomere loss, lagging strand defects, telomere-induced DNA damage, and premature senescence with G1 arrest. Our data suggest POT1(L259S) is a pathogenic driver of IPF and provide insights into gene therapy options.
Project description:Idiopathic pulmonary fibrosis (IPF) is an age-related disease featuring progressive lung scarring. To elucidate the molecular basis of IPF, we performed exome sequencing of familial kindreds with pulmonary fibrosis. Gene burden analysis comparing 78 European cases and 2,816 controls implicated PARN, an exoribonuclease with no previous connection to telomere biology or disease, with five new heterozygous damaging mutations in unrelated cases and none in controls (P = 1.3 × 10(-8)); mutations were shared by all affected relatives (odds in favor of linkage = 4,096:1). RTEL1, an established locus for dyskeratosis congenita, harbored significantly more new damaging and missense variants at conserved residues in cases than in controls (P = 1.6 × 10(-6)). PARN and RTEL1 mutation carriers had shortened leukocyte telomere lengths, and we observed epigenetic inheritance of short telomeres in family members. Together, these genes explain ~7% of familial pulmonary fibrosis and strengthen the link between lung fibrosis and telomere dysfunction.
Project description:Idiopathic pulmonary fibrosis (IPF) is an aging-associated, recalcitrant lung disease with historically limited therapeutic options. The recent approval of two drugs, pirfenidone and nintedanib, by the US Food and Drug Administration in 2014 has heralded a new era in its management. Both drugs have demonstrated efficacy in phase III clinical trials by retarding the rate of progression of IPF; neither drug appears to be able to completely arrest disease progression. Advances in the understanding of IPF pathobiology have led to an unprecedented expansion in the number of potential therapeutic targets. Drugs targeting several of these are under investigation in various stages of clinical development. Here, we provide a brief overview of the drugs that are currently approved and others in phase II clinical trials. Future therapeutic opportunities that target novel pathways, including some that are associated with the biology of aging, are examined. A multi-targeted approach, potentially with combination therapies, and identification of individual patients (or subsets of patients) who may respond more favourably to specific agents are likely to be more effective.
Project description:Idiopathic pulmonary fibrosis (IPF) is a progressive disease with a dismal prognosis. The average life expectancy of untreated patients with IPF is only 3 to 4 years. Decline in forced vital capacity (FVC) in patients with IPF appears to be almost linear, with patients with well-preserved FVC at baseline experiencing the same rate of decline in FVC as patients with more advanced disease. Two antifibrotic therapies have been approved for the treatment of IPF: nintedanib and pirfenidone. These drugs slow decline in lung function and reduce the risk of acute respiratory deteriorations, which are associated with very high morbidity and mortality. Individual clinical trials have not been powered to show reductions in mortality, but analyses of pooled data from clinical trials, as well as observational studies, suggest that antifibrotic therapies improve life expectancy. Despite this, many individuals with IPF remain untreated. In many cases, this is because the physician perceives that the disease is stable and so does not warrant therapy, or has concerns over the potential side-effects of antifibrotic drugs. There remains a need to educate pulmonologists that IPF is a progressive, irreversible and fatal disease and that prompt treatment is critical to preserving patients' lung function and improving outcomes. Most individuals can tolerate antifibrotic therapy, and dose adjustment has been shown to be effective at reducing side effects without compromising efficacy. In addition to anti-fibrotic therapies, individuals with IPF benefit from a holistic approach to their care that includes symptom management and supportive care tailored to the needs of the individual. An animation illustrating the themes covered in this article will be available at: http://www.usscicomms.com/respiratory/maher/treatment-of-IPF .
Project description:Telomere shortening is associated with idiopathic pulmonary fibrosis (IPF), a high-morbidity and high-mortality lung disease of unknown etiology. However, the underlying mechanisms remain largely unclear. In this study, wild-type (WT) mice with normal telomeres and generation 3 (G3) or G2 telomerase RNA component (TERC) knockout Terc-/- mice with short telomeres were treated with and without lipopolysaccharide (LPS) or bleomycin by intratracheal injection. We show that under LPS induction, G3 Terc-/- mice develop aggravated pulmonary fibrosis as indicated by significantly increased ?-SMA, collagen I and hydroxyproline content. Interestingly, TGF-?/Smads signaling is markedly activated in the lungs of G3 Terc-/- mice, as indicated by markedly elevated levels of phosphorylated Smad3 and TGF-?1, compared with those of WT mice. This TGF-?/Smads signaling activation is significantly increased in the lungs of LPS-treated G3 Terc-/- mice compared with those of LPS-treated WT or untreated G3 Terc-/- mice. A similar pattern of TGF-?/Smads signaling activation and the enhancing role of telomere shortening in pulmonary fibrosis are also confirmed in bleomycin-induced model. Moreover, LPS challenge produced more present cellular senescence, apoptosis and infiltration of innate immune cells, including macrophages and neutrophils in the lungs of G3 Terc-/- mice, compared with WT mice. To our knowledge, this is the first time to report telomere shortening activated TGF-?/Smads signaling in lungs. Our data suggest that telomere shortening cooperated with environment-induced lung injury accelerates the development of pulmonary fibrosis, and telomere shortening confers an inherent enhancing factor to the genesis of IPF through activation of TGF-?/Smads signaling.
Project description:Background and objectiveIPF is an ageing-related lung disorder featuring progressive lung scarring. IPF patients are frequently identified with short telomeres but coding mutations in telomerase can only explain a minority of cases. Sex hormones regulate telomerase activity in vitro and levels of sex hormones are related to LTL. The objective of this study was to explore whether sex hormones were associated with LTL, whether they interacted with genetic variants in telomerase and whether polymorphisms in the exon of androgen metabolism genes were associated with plasma testosterone concentrations in male IPF patients.MethodsA case-control study was performed on 101 male IPF subjects and 51 age-matched healthy controls. Early morning plasma sex hormones were quantified, and whole-exome sequencing was used to identify rare protein-altering variants of telomerase and SNP in the exon of androgen metabolism genes. LTL was analysed by PCR and expressed as a T/S ratio.ResultsLTL, testosterone and DHT were decreased significantly in the IPF group. After adjustments for age and variant status in telomerase-related genes, only testosterone was positively associated with LTL (P = 0.001). No significant interaction (P = 0.661) was observed between rare protein-altering variants of telomerase and testosterone. No coding SNP in androgen metabolism genes were significantly associated with testosterone concentrations.ConclusionPlasma testosterone is associated with LTL independent of age or rare protein-altering variants of telomerase. No genetic variations of androgen-related pathway genes are associated with androgen concentrations. Further studies are warranted to examine whether hormonal interventions might retard telomere loss in male IPF patients.
Project description:BackgroundDue to the inadequacy of published evidence, association of telomere length (TL), obesity and tobacco smoking with idiopathic pulmonary fibrosis (IPF) remains unclear. The aim of the study was to explore whether these exposures genetically affected the risk of the disease.MethodsGenetic variants from genome-wide association studies for TL, body mass index (BMI), body fat percentage (BFP) and tobacco smoking (including maternal smoking) were used as instrumental variables. Inverse-variance weighted were mainly adopted to determine the genetic association of these exposures with IPF. All analyses were conducted by R-software (version 3.6.1).ResultsFirstly, longer TL was associated with the decreased risk of IPF (OR = 0.475 per SD increase in TL, 95%CI = 0.336 ~ 0.670, P<0.001). Secondly, higher levels of BMI and BFP were related to the increased risk of the disease (OR = 1.425 per SD increase in BMI level, 95%CI = 1.114 ~ 1.823, P = 0.005; OR = 1.702 per SD increase in BFP level, 95%CI = 1.202 ~ 2.409, P = 0.003). Thirdly, maternal smoking was implicated in the increased risk of the disease (OR = 13.183 per SD increase in the prevalence of maternal smoking, 95%CI = 1.820 ~ 95.484, P = 0.011).ConclusionTL should be a genetic risk factor for IPF. Obesity and exposure to tobacco smoking as a fetus might also contribute to the development of this fibrotic diseases. These findings should be verified by future studies.