Real-World Multicenter Experience of Immunosuppression Minimization Among 661 Liver Transplant Recipients.

BACKGROUND Long-term morbidity and mortality in liver transplant recipients is frequently secondary to immunosuppression toxicity. However, data are scarce regarding immunosuppression minimization in clinical practice. MATERIAL AND METHODS In this cross-sectional, multicenter study, we reviewed the indications of immunosuppression minimization (defined as tacrolimus levels below 5 ng/mL or cyclosporine levels below 50 ng/mL) among 661 liver transplant recipients, as well as associated factors and the effect on renal function. RESULTS Fifty-three percent of the patients received minimized immunosuppression. The median time from transplantation to minimization was 32 months. The most frequent indications were renal insufficiency (49%), cardiovascular risk (19%), de novo malignancy (8%), and cardiovascular disease (7%). The factors associated with minimization were older age at transplantation, longer post-transplant follow-up, pre-transplant diabetes mellitus and renal dysfunction, and the hospital where the patients were being followed. The patients who were minimized because of renal insufficiency had a significant improvement in renal function (decrease of the median serum creatinine level, from 1.50 to 1.34 mg/dL; P=0.004). Renal function significantly improved in patients minimized for other indications, too. In the long term, glomerular filtration rate significantly decreased in non-minimized patients and remained stable in minimized patients. CONCLUSIONS Immunosuppression minimization is frequently undertaken in long-term liver transplant recipients, mainly for renal insufficiency. Substantial variability exists regarding the use of IS minimization among centers

Contribution of genetic and epigenetic mechanisms to Wnt pathway activity in prevalent skeletal disorders

Producción CientíficaWe reported previously that the expression of Wnt-related genes is lower in osteoporotic hip fractures than in 26 osteoarthritis. We aimed to confirm those results by analyzing β-catenin levels and explored potential genetic 27 and epigenetic mechanisms involved. 28 β-Catenin gene expression and nuclear levelswere analyzed by real time PCR and confocal immunofluorescence. 29 Increased nuclear β-catenin was found in osteoblasts isolated from patients with osteoarthritis (99 ± 4 30 units vs. 76 ± 12, p = 0.01, n = 10), without differences in gene transcription, which is consistent with 31 a post-translational down-regulation of β-catenin and decreased Wnt pathway activity. 32 Twenty four single nucleotide polymorphisms (SNPs) of genes showing differential expression between fractures 33 and osteoarthritis (WNT4, WNT10A, WNT16 and SFRP1) were analyzed in DNA isolated from blood of 853 pa- 34 tients. The genotypic frequencies were similar in both groups of patients, with no significant differences. 35 Methylation ofWnt pathway genes was analyzed in bone tissue samples (15 with fractures and 15 with osteo- 36 arthritis) by interrogating a CpG-based methylation array. Six genes showed significant methylation differences 37 between both groups of patients: FZD10, TBL1X, CSNK1E, WNT8A, CSNK1A1L and SFRP4. The DNA demethylating 38 agent 5-deoxycytidine up-regulated 8 genes, including FZD10, in an osteoblast-like cell line, whereas it down- 39 regulated other 16 genes. 40 In conclusion,Wnt activity is reduced in patientswith hip fractures, in comparisonwith thosewith osteoarthritis. 41 It does not appear to be related to differences in the allele frequencies of the Wnt genes studied. On the other 42 hand, methylation differences between both groups could contribute to explain the differences inWnt activit

Accumulation of poly(A) RNA in nuclear granules enriched in Sam68 in motor neurons from the SMNA7 mouse model of SMA

Spinal muscular atrophy (SMA) is a severe motor neuron (MN) disease caused by the deletion or mutation of the survival motor neuron 1 (SMN1) gene, which results in reduced levels of the SMN protein and the selective degeneration of lower MNs. The best-known function of SMN is the biogenesis of spliceosomal snRNPs, the major components of the pre-mRNA splicing machinery. Therefore, SMN deficiency in SMA leads to widespread splicing abnormalities. We used the SMN?7 mouse model of SMA to investigate the cellular reorganization of polyadenylated mRNAs associated with the splicing dysfunction in MNs. We demonstrate that SMN deficiency induced the abnormal nuclear accumulation in euchromatin domains of poly(A) RNA granules (PARGs) enriched in the splicing regulator Sam68. However, these granules lacked other RNA-binding proteins, such as TDP43, PABPN1, hnRNPA12B, REF and Y14, which are essential for mRNA processing and nuclear export. These effects were accompanied by changes in the alternative splicing of the Sam68-dependent Bcl-x and Nrnx1 genes, as well as changes in the relative accumulation of the intron-containing Chat, Chodl, Myh9 and Myh14 mRNAs, which are all important for MN functions. PARG-containing MNs were observed at presymptomatic SMA stage, increasing their number during the symptomatic stage. Moreover, the massive accumulations of poly(A) RNA granules in MNs was accompanied by the cytoplasmic depletion of polyadenylated mRNAs for their translation. We suggest that the SMN-dependent abnormal accumulation of polyadenylated mRNAs and Sam68 in PARGs reflects a severe dysfunction of both mRNA processing and translation, which could contribute to SMA pathogenesis.This work was supported by grants from: “Dirección General de Investigación” of Spain (BFU2014-54754-P and SAF2015-70801-R, cofinanced by FEDER) and “Instituto de Investigación Marqués de Valdecilla-IDIVAL (NVAL17/22). Dr. Tapia is the recipient of a grant from SMA Europe and FundAME (Spain)

A Cell Cycle Role for the Epigenetic Factor CTCF-L/BORIS

CTCF is a ubiquitous epigenetic regulator that has been proposed as a master keeper of chromatin organisation. CTCF-like, or BORIS, is thought to antagonise CTCF and has been found in normal testis, ovary and a large variety of tumour cells. The cellular function of BORIS remains intriguing although it might be involved in developmental reprogramming of gene expression patterns. We here unravel the expression of CTCF and BORIS proteins throughout human epidermis. While CTCF is widely distributed within the nucleus, BORIS is confined to the nucleolus and other euchromatin domains. Nascent RNA experiments in primary keratinocytes revealed that endogenous BORIS is present in active transcription sites. Interestingly, BORIS also localises to interphase centrosomes suggesting a role in the cell cycle. Blocking the cell cycle at S phase or mitosis, or causing DNA damage, produced a striking accumulation of BORIS. Consistently, ectopic expression of wild type or GFP- BORIS provoked a higher rate of S phase cells as well as genomic instability by mitosis failure. Furthermore, downregulation of endogenous BORIS by specific shRNAs inhibited both RNA transcription and cell cycle progression. The results altogether suggest a role for BORIS in coordinating S phase events with mitosis

Nucleolus: the fascinating nuclear body

Nucleoli are the prominent contrasted structures of the cell nucleus. In the nucleolus, ribosomal RNAs are synthesized, processed and assembled with ribosomal proteins. RNA polymerase I synthesizes the ribosomal RNAs and this activity is cell cycle regulated. The nucleolus reveals the functional organization of the nucleus in which the compartmentation of the different steps of ribosome biogenesis is observed whereas the nucleolar machineries are in permanent exchange with the nucleoplasm and other nuclear bodies. After mitosis, nucleolar assembly is a time and space regulated process controlled by the cell cycle. In addition, by generating a large volume in the nucleus with apparently no RNA polymerase II activity, the nucleolus creates a domain of retention/sequestration of molecules normally active outside the nucleolus. Viruses interact with the nucleolus and recruit nucleolar proteins to facilitate virus replication. The nucleolus is also a sensor of stress due to the redistribution of the ribosomal proteins in the nucleoplasm by nucleolus disruption. The nucleolus plays several crucial functions in the nucleus: in addition to its function as ribosome factory of the cells it is a multifunctional nuclear domain, and nucleolar activity is linked with several pathologies. Perspectives on the evolution of this research area are proposed