Daily Caffeine Consumption May Increase the Risk of Acute Kidney Injury Related to Platinum-Salt Chemotherapy in Thoracic Cancer Patients: A Translational Study.

Although their efficacy has been well-established in Oncology, the use of platinum salts remains limited due to the occurrence of acute kidney injury (AKI). Caffeine has been suggested as a potential pathophysiological actor of platinum-salt-induced AKI, through its hemodynamic effects. This work aims to study the association between caffeine consumption and the risk of platinum-salt-induced AKI, based on both clinical and experimental data. The clinical study involved a single-center prospective cohort study including all consecutive thoracic cancer patients receiving a first-line platinum-salt (cisplatin or carboplatin) chemotherapy between January 2017 and December 2018. The association between daily caffeine consumption (assessed by a validated auto-questionnaire) and the risk of platinum-salt induced AKI or death was estimated by cause-specific Cox proportional hazards models adjusted for several known confounders. Cellular viability, relative renal NGAL expression and/or BUN levels were assessed in models of renal tubular cells and mice co-exposed to cisplatin and increasing doses of caffeine. Overall, 108 patients were included (mean age 61.7 years, 65% men, 80% tobacco users), among whom 34 (31.5%) experienced a platinum-salt-induced AKI (67% Grade 1) over a 6-month median follow-up. The group of high-caffeine consumption (≥386 mg/day) had a two-fold higher hazard of AKI (adjusted HR [95% CI], 2.19 [1.05; 4.57]), without any significant association with mortality. These results are consistent with experimental data confirming enhanced cisplatin-related nephrotoxicity in the presence of increasing doses of caffeine, in both in vitro and in vivo models. Overall, this study suggests a potentially deleterious effect of high doses of daily caffeine consumption on the risk of platinum-salt-related AKI, in both clinical and experimental settings.

Extracorporeal Photopheresis Reduces Fibrotic and Inflammatory Transcriptomic Biological Marker of Chronic Antibody-mediated Kidney Rejection.

Background: The benefit of extracorporeal photopheresis on the course of kidney transplant rejection is unknown. The aim of our study was to investigate the variations in transcriptomics on graft biopsies when extracorporeal photopheresis was used to treat chronic humoral rejection after kidney transplantation. Methods: We retrospectively analyzed the mRNA expression of 770 genes of interest in graft biopsies performed before and after treatment. Eight patients received an average of 23 extracorporeal photopheresis sessions over 4 mo between the 2 biopsies. Results: Transcriptomic analysis of the graft biopsies identified a significant (adjusted P < 0.05) increase in CAV1 mRNA in all patients and a significant decrease in CD19, IL21, PAX5, and SFTPA2 mRNAs in 7 of 8 patients. Conclusions: In patients treated with extracorporeal photopheresis for chronic humoral rejection after renal transplantation, omic analysis of repeated biopsies shows a reduction in fibrotic and inflammatory transcriptomic biologicals markers.

MUC1 Drives the Progression and Chemoresistance of Clear Cell Renal Carcinomas.

While the transmembrane glycoprotein mucin 1 (MUC1) is clustered at the apical borders of normal epithelial cells, with transformation and loss of polarity, MUC1 is found at high levels in the cytosol and is uniformly distributed over the entire surface of carcinoma cells, where it can promote tumor progression and adversely affects the response to therapy. Clear cell renal cell carcinoma (ccRCC), the main histotype of kidney cancer, is typically highly resistant to conventional and targeted therapies for reasons that remain largely unknown. In this context, we investigated whether MUC1 also plays a pivotal role in the cellular and molecular events driving ccRCC progression and chemoresistance. We showed, using loss- and gain-of-function approaches in ccRCC-derived cell lines, that MUC1 not only influences tumor progression but also induces a multi-drug-resistant profile reminiscent of the activation of ABC drug efflux transporters. Overall, our results suggest that targeting MUC1 may represent a novel therapeutic approach to limit ccRCC progression and improve drug sensitivity.

Integrating rare genetic variants into DPYD pharmacogenetic testing may help preventing fluoropyrimidine-induced toxicity.

Variability in genes involved in drug pharmacokinetics or drug response can be responsible for suboptimal treatment efficacy or predispose to adverse drug reactions. In addition to common genetic variations, large-scale sequencing studies have uncovered multiple rare genetic variants predicted to cause functional alterations in genes encoding proteins implicated in drug metabolism, transport and response. To understand the functional importance of rare genetic variants in DPYD, a pharmacogene whose alterations can cause severe toxicity in patients exposed to fluoropyrimidine-based regimens, massively parallel sequencing of the exonic regions and flanking splice junctions of the DPYD gene was performed in a series of nearly 3000 patients categorized according to pre-emptive DPD enzyme activity using the dihydrouracil/uracil ([UH2]/[U]) plasma ratio as a surrogate marker of DPD activity. Our results underscore the importance of integrating next-generation sequencing-based pharmacogenomic interpretation into clinical decision making to minimize fluoropyrimidine-based chemotherapy toxicity without altering treatment efficacy.

miR-92a-3p regulates cisplatin-induced cancer cell death.

Non-small cell lung cancer is characterized by a dismal prognosis largely owing to inefficient diagnosis and tenacious drug resistance. Therefore, the identification of new molecular determinants underlying sensitivity of cancer cells to existing therapy is of particular importance to develop new effective combinatorial treatment strategy. MicroRNAs (miRNAs), a class of small non-coding RNAs, have been established as master regulators of a variety of cellular processes that play a key role in tumor initiation, progression and metastasis. This, along with their widespread deregulation in many distinct cancers, has triggered enthusiasm for miRNAs as novel therapeutic targets for cancer management, in particular in patients with refractory cancers such as those harboring KRAS mutations. In this study, we performed a loss-of-function screening approach to identify miRNAs whose silencing promotes sensitivity of lung adenocarcinoma (LUAD) cells to cisplatin. Our results showed in particular that antisense oligonucleotides directed against miR-92a-3p, a member of the oncogenic miR-17 ~ 92 cluster, caused the greatest increase in the sensitivity of KRAS-mutated LUAD cells to cisplatin. In addition, we demonstrated that this miRNA finely regulates the apoptotic threshold and the proliferative capacity of various tumor cell lines with distinct genetic alterations. Collectively, these data suggest that targeting miR-92a-3p may serve as an effective strategy to overcome treatment resistance of solid tumors.

Pervasive role of the long noncoding RNA DNM3OS in development and diseases.

Thousands of unique noncoding RNAs (ncRNAs) are expressed in human cells, some are tissue or cell type specific whereas others are considered as house-keeping molecules. Studies over the last decade have modified our perception of ncRNAs from transcriptional noise to functional regulatory transcripts that influence a variety of molecular processes such as chromatin remodeling, transcription, post-transcriptional modifications, or signal transduction. Consequently, aberrant expression of many ncRNAs plays a causative role in the initiation and progression of various diseases. Since the identification of its developmental role, the long ncRNA DNM3OS (Dynamin 3 Opposite Strand) has attracted attention of researchers in distinct fields including oncology, fibroproliferative diseases, or bone disorders. Mechanistic studies have in particular revealed the multifaceted nature of DNM3OS and its important pathogenic role in several human disorders. In this review, we summarize the current knowledge of DNM3OS functions in diseases, with an emphasis on its potential as a novel therapeutic target. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Istradefylline protects from cisplatin-induced nephrotoxicity and peripheral neuropathy while preserving cisplatin antitumor effects.

Cisplatin is a potent chemotherapeutic drug that is widely used in the treatment of various solid cancers. However, its clinical effectiveness is strongly limited by frequent severe adverse effects, in particular nephrotoxicity and chemotherapy-induced peripheral neuropathy. Thus, there is an urgent medical need to identify novel strategies that limit cisplatin-induced toxicity. In the present study, we show that the FDA-approved adenosine A2A receptor antagonist istradefylline (KW6002) protected from cisplatin-induced nephrotoxicity and neuropathic pain in mice with or without tumors. Moreover, we also demonstrate that the antitumoral properties of cisplatin were not altered by istradefylline in tumor-bearing mice and could even be potentiated. Altogether, our results support the use of istradefylline as a valuable preventive approach for the clinical management of patients undergoing cisplatin treatment.

The Versatile Role of miR-21 in Renal Homeostasis and Diseases.

MicroRNAs (miRNAs) are small, non-coding RNA species that control gene expression and confer robustness to biological processes. Over the last two decades, their important roles during kidney development, homeostasis and the treatment of diseases have been established, in particular during the onset and progression of various forms of acute and chronic renal disorders. In recent years, miR-21, one of the best-characterized miRNAs to date, has received much attention in renal physiology in particular given its high degree of conservation and expression in kidneys, as well as its potent pathogenic role in various debilitating renal diseases. This review summarizes the current knowledge on miR-21's involvement in both renal homeostasis and diseases, in particular its double-edged-sword role in acute versus chronic kidney injuries. Finally, we also discuss the potential of miR-21 as a biomarker and therapeutic target in renal diseases.

A Double-Negative Feedback Interaction between miR-21 and PPAR-α in Clear Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) is the main histotype of kidney cancer, which is typically highly resistant to conventional therapies and known for abnormal lipid accumulation. In this context, we focused our attention on miR-21, an oncogenic miRNA overexpressed in ccRCC, and peroxysome proliferator-activated receptor-α (PPAR- α), one master regulator of lipid metabolism targeted by miR-21. First, in a cohort of 52 primary ccRCC samples, using RT-qPCR and immunohistochemistry, we showed that miR-21 overexpression was correlated with PPAR-α downregulation. Then, in ACHN and 786-O cells, using RT-qPCR, the luciferase reporter gene, chromatin immunoprecipitation, and Western blotting, we showed that PPAR-α overexpression (i) decreased miR-21 expression, AP-1 and NF-κB transcriptional activity, and the binding of AP-1 and NF-κB to the miR-21 promoter and (ii) increased PTEN and PDCD4 expressions. In contrast, using pre-miR-21 transfection, miR-21 overexpression decreased PPAR-α expression and transcriptional activity mediated by PPAR-α, whereas the anti-miR-21 (LNA-21) strategy increased PPAR-α expression, but also the expression of its targets involved in fatty acid oxidation. In this study, we showed a double-negative feedback interaction between miR-21 and PPAR-α. In ccRCC, miR-21 silencing could be therapeutically exploited to restore PPAR-α expression and consequently inhibit the oncogenic events mediated by the aberrant lipid metabolism of ccRCC.

Impact of Tacrolimus Daily Dose Limitation in Renal Transplant Recipients Expressing CYP3A5: A Retrospective Study.

The pharmacokinetic variability of tacrolimus can be partly explained by CYP3A5 activity. Our objective was to evaluate a tacrolimus sparing policy on renal graft outcome according to CYP3A5 6986A>G genetic polymorphism. This retrospective study included 1114 recipients with a median follow-up of 6.3 years. Genotyping of the 6986A>G allelic variant corresponding to CYP3A5*3 was systematically performed. One year after transplantation, tacrolimus blood trough concentration (C0) target range was 5-7 ng/mL. However, daily dose was capped to 0.10 mg/kg/day regardless of the CYP3A5 genotype. A total 208 CYP3A5*1/- patients were included. Despite a higher daily dose, CYP3A5*1/- recipients exhibited lower C0 during follow-up (p < 0.01). Multivariate analysis did not show any significant influence of CYP3A5*1/- genotype (HR = 0.70, 0.46-1.07, p = 0.10) on patient-graft survival. Glomerular Filtration Rate (GFR) decline was significantly lower for the CYP3A5*1/- group (p = 0.02). The CYP3A5*1/- genotype did not significantly impact the risk of biopsy-proven acute rejection (BPAR) (HR = 1.01, 0.68-1.49, p = 0.97) despite significantly lower C0. Based on our experience, a strategy of tacrolimus capping is associated with a better GFR evolution in CYP3A5*1/- recipients without any significant increase of BPAR incidence. Our study raised some issues about specific therapeutic tacrolimus C0 targets for CYP3A5*1/- patients and suggests to set up randomized control studies in this specific population.

MUC1 Mitigates Renal Injury and Inflammation in Endotoxin-Induced Acute Kidney Injury by Inhibiting the TLR4-MD2 Axis and Reducing Pro-inflammatory Macrophages Infiltration.

ABSTRACT: Sepsis is the leading cause of acute kidney injury (AKI) in critical care patients. A cornerstone of sepsis-associated AKI is dysregulated inflammation driven by excessive activation of Toll-like receptor 4 (TLR4) pathway. MUC1, a membrane-bound mucin expressed in both epithelial tubular cells and renal macrophages, has been shown to be involved in the regulation of TLRs. Therefore, we hypothesized that MUC1 could mitigate the renal inflammatory response to TLR4 activation. To test this hypothesis, we used a murine model of endotoxin-induced AKI by intraperitoneal injection of LPS. We showed that Muc1-/- mice have a more severe renal dysfunction, an increased activation of the tissular NF-kB pathway and secreted more pro inflammatory cytokines compare to Muc1+/+ mice. By flow cytometry, we observed that the proportion of M1 (pro-inflammatory) macrophages in the kidneys of Muc1-/- mice was significantly increased. In human and murine primary macrophages, we showed that MUC1 is only induced in M1 type macrophages and that macrophages derived from Muc1-/- mice secreted more pro-inflammatory cytokines. Eventually, in HEK293 cells, we showed that MUC1 cytosolic domain (CT) seems necessary for the negative regulation of TLR4 by proximity ligation assay, MUC1-CT is in close relationship with TLR4 and acts as a competitive inhibitor of the recruitment of MYD88. Overall our results support that in the context of endotoxin-induced AKI, MUC1 plays a significant role in controlling disease severity by regulating negatively the TLR4-MD2 axis.

Diagnostic utility of whole-genome sequencing for nephronophthisis.

Next-generation sequencing has revolutionized the molecular diagnosis of individuals affected by genetic kidney diseases. Indeed, rapid genetic testing in individuals with suspected inherited nephropathy has not only important implications for diagnosis and prognosis but also for genetic counseling. Nephronophthisis (NPHP) and related syndromes, a leading cause of end-stage renal failure, are autosomal recessive disorders characterized by the variable presentation and considerable locus heterogeneity with more than 90 genes described as single-gene causes. In this case report, we demonstrate the utility of whole-genome sequencing (WGS) for the molecular diagnosis of NPHP by identifying two putative disease-causing intronic mutations in the NPHP3 gene, including one deep intronic variant. We further show that both intronic variants, by affecting splicing, result in a truncated nephrocystin-3 protein. This study provides a framework for applying WGS as a first-line diagnostic tool for highly heterogeneous disease such as NPHP and further suggests that deep intronic variations are an important underestimated cause of monogenic disorders.

[Fundamental aspects of oncogenesis]. / Aspects fondamentaux du développement tumoral.

Tumorigenesis has traditionally been considered as a multi-step process involving the activation of oncogenes as well as the inactivation of tumor suppressor genes. However, the mechanisms driving cancer initiation and progression are not restricted to molecular alterations and instead should be viewed as a complex process that interfaces with the entire organism. This didactic review provides an integrated and global view of the key fundamental principles of cancer development.

Caveolin-1 rs4730751 single-nucleotide polymorphism may not influence kidney transplant allograft survival.

Caveolin-1 is a protein (encoded by the CAV1 gene) supposedly harboring a protective effect against fibrosis. CAV1 rs4730751 single nucleotide polymorphism (SNP) AA genotype was initially associated with lower graft survival compared to non-AA. However, subsequent studies could not find the same effect. CAV1 rs4730751 SNP was investigated on 918 kidney donors. Multivariate Cox-model analyses were performed to evaluate risk factors for graft loss. Longitudinal changes on long-term estimated glomerular filtration rate (eGFRs) were evaluated with a linear mixed model. Histopathological findings from protocolled biopsies after 3 months post transplantation were also analyzed. Donor CAV1 rs4730751 genotyping proportions were 7.1% for AA, 41.6% for AC and 51.3% for CC. The AA genotype, compared to non-AA, was not associated with lower graft survival censored or not for death (multivariate analysis: HR = 1.23 [0.74-2.05] and HR = 1.27 [0.84-1.92]). Linear mixed model on long-term eGFRs revealed also no significant difference according to the genotype, yet we observed a trend. AA genotype was also not associated with a higher degree of fibrosis index on protocolled kidney biopsies at 3 months. To conclude, donor CAV1 rs4730751 SNP may impact on kidney transplantation outcomes, but this study could not confirm this hypothesis.

Prevention of Cisplatin-Induced Acute Kidney Injury: A Systematic Review and Meta-Analysis.

PURPOSE: Cisplatin-induced acute kidney injury (CIA) is a serious adverse event that affects 20-40% of exposed patients, despite any implemented precaution to avoid it. The aim of this work was therefore to identify a relevant nephroprotective method for CIA. METHODS: We searched Pubmed, Embase, and Web of Science from 1 January 1978 to 1 June 2018, without language restriction. All studies (observational and interventional) assessing a CIA prevention method for adults receiving at least one course of cisplatin were eligible. The primary outcome was acute nephrotoxicity, as defined by the AKI-KDIGO classification (2012). The odds ratio and corresponding 95% confidence interval were used to assess the associations. We used narrative synthesis in case of heterogeneity regarding intervention, population, or outcome. When possible, a random-effects model was used to pool studies. The heterogeneity between studies was quantified (I2), and multiple meta-regressions were carried out to identify potential confounders. RESULTS: Within 4520 eligible studies, 51 articles fulfilling the selection criteria were included in the review, assessing 21 different prevention methods. A meta-analysis could only be performed on the 15 observational studies concerning magnesium supplementation (1841 patients), and showed a significant nephroprotective effect for all combined grades of CIA (OR 0.24, [0.19-0.32], I2 = 0.0%). This significant nephroprotective effect was also observed for grades 2 and 3 CIA (OR 0.22, [0.14-0.33], I2 = 0.0% and OR 0.25, [0.08-0.76], I2 = 0.0%, respectively). CONCLUSION: While no method of prevention had so far demonstrated its indisputable efficacy, our results highlight the potential protective effect of magnesium supplementation on cisplatin-induced acute nephrotoxicity. TRIAL REGISTRATION: This study is registered in PROSPERO, CRD42018090612.

The Long Noncoding RNA DNM3OS Is a Reservoir of FibromiRs with Major Functions in Lung Fibroblast Response to TGF-ß and Pulmonary Fibrosis.

Rationale: Given the paucity of effective treatments for idiopathic pulmonary fibrosis (IPF), new insights into the deleterious mechanisms controlling lung fibroblast activation, the key cell type driving the fibrogenic process, are essential to develop new therapeutic strategies. TGF-ß (transforming growth factor-ß) is the main profibrotic factor, but its inhibition is associated with severe side effects because of its pleiotropic role. Objectives: To determine if downstream noncoding effectors of TGF-ß in fibroblasts may represent new effective therapeutic targets whose modulation may be well tolerated. Methods: We investigated the whole noncoding fraction of TGF-ß-stimulated lung fibroblast transcriptome to identify new genomic determinants of lung fibroblast differentiation into myofibroblasts. Differential expression of the long noncoding RNA (lncRNA) DNM3OS (dynamin 3 opposite strand) and its associated microRNAs (miRNAs) was validated in a murine model of pulmonary fibrosis and in IPF tissue samples. Distinct and complementary antisense oligonucleotide-based strategies aiming at interfering with DNM3OS were used to elucidate the role of DNM3OS and its associated miRNAs in IPF pathogenesis. Measurements and Main Results: We identified DNM3OS as a fibroblast-specific critical downstream effector of TGF-ß-induced lung myofibroblast activation. Mechanistically, DNM3OS regulates this process in trans by giving rise to three distinct profibrotic mature miRNAs (i.e., miR-199a-5p/3p and miR-214-3p), which influence SMAD and non-SMAD components of TGF-ß signaling in a multifaceted way. In vivo, we showed that interfering with DNM3OS function not only prevents lung fibrosis but also improves established pulmonary fibrosis. Conclusions: Pharmacological approaches aiming at interfering with the lncRNA DNM3OS may represent new effective therapeutic strategies in IPF.

Non-Coding RNAs as New Therapeutic Targets in the Context of Renal Fibrosis.

Fibrosis, or tissue scarring, is defined as the excessive, persistent and destructive accumulation of extracellular matrix components in response to chronic tissue injury. Renal fibrosis represents the final stage of most chronic kidney diseases and contributes to the progressive and irreversible decline in kidney function. Limited therapeutic options are available and the molecular mechanisms governing the renal fibrosis process are complex and remain poorly understood. Recently, the role of non-coding RNAs, and in particular microRNAs (miRNAs), has been described in kidney fibrosis. Seminal studies have highlighted their potential importance as new therapeutic targets and innovative diagnostic and/or prognostic biomarkers. This review will summarize recent scientific advances and will discuss potential clinical applications as well as future research directions.

Knockout of receptor for advanced glycation end-products attenuates age-related renal lesions.

Pro-aging effects of endogenous advanced glycation end-products (AGEs) have been reported, and there is increasing interest in the pro-inflammatory and -fibrotic effects of their binding to RAGE (the main AGE receptor). The role of dietary AGEs in aging remains ill-defined, but the predominantly renal accumulation of dietary carboxymethyllysine (CML) suggests the kidneys may be particularly affected. We studied the impact of RAGE invalidation and a CML-enriched diet on renal aging. Two-month-old male, wild-type (WT) and RAGE-/- C57Bl/6 mice were fed a control or a CML-enriched diet (200 µg CML/gfood ) for 18 months. Compared to controls, we observed higher CML levels in the kidneys of both CML WT and CML RAGE-/- mice, with a predominantly tubular localization. The CML-rich diet had no significant impact on the studied renal parameters, whereby only a trend to worsening glomerular sclerosis was detected. Irrespective of diet, RAGE-/- mice were significantly protected against nephrosclerosis lesions (hyalinosis, tubular atrophy, fibrosis and glomerular sclerosis) and renal senile apolipoprotein A-II (ApoA-II) amyloidosis (p < 0.001). A positive linear correlation between sclerosis score and ApoA-II amyloidosis score (r = 0.92) was observed. Compared with old WT mice, old RAGE-/- mice exhibited lower expression of inflammation markers and activation of AKT, and greater expression of Sod2 and SIRT1. Overall, nephrosclerosis lesions and senile amyloidosis were significantly reduced in RAGE-/- mice, indicating a protective effect of RAGE deletion with respect to renal aging. This could be due to reduced inflammation and oxidative stress in RAGE-/- mice, suggesting RAGE is an important receptor in so-called inflamm-aging.

Tacrolimus-induced nephrotoxicity in mice is associated with microRNA deregulation.

Although Tacrolimus is an immunosuppressive drug widely used in renal transplantation, its chronic use paradoxically induces nephrotoxic effects, in particular renal fibrosis, which is responsible for chronic allograft dysfunction and represents a major prognostic factor of allograft survival. As molecular pathways and mechanisms involved in Tacrolimus-induced fibrogenic response are poorly elucidated, we assessed whether miRNAs are involved in the nephrotoxic effects mediated by Tacrolimus. Treatment of CD-1 mice with Tacrolimus (1 mg/kg/d for 28 days) resulted in kidney injury and was associated with alteration of a gene expression signature associated with cellular stress, fibrosis and inflammation. Tacrolimus also affected renal miRNA expression, including miRNAs previously involved in fibrotic and inflammatory processes as "fibromirs" such as miR-21-5p, miR-199a-5p and miR-214-3p. In agreement with in vivo data, Renal Proximal Tubular Epithelial cells exposed to Tacrolimus (25 and 50 µM) showed upregulation of miR-21-5p and the concomitant induction of epithelial phenotypic changes, inflammation and oxidative stress. In conclusion, this study suggests for the first time that miRNAs, especially fibromiRs, participate to Tacrolimus-induced nephrotoxic effects. Therefore, targeting miRNAs may be a new therapeutic option to counteract Tacrolimus deleterious effects on kidney.