title: Splicing alterations in human renal allografts: detection of a new splice variant of protein kinase Par1/Emk1 whose expression is associated with an increase of inflammation in protocol biopsies of transplanted patients.
abstract: Protein kinase Emk1/Par1 (GenBank accession no. X97630) has been identified as a regulator of the immune system homeostasis. Since immunological factors are critical for the development of chronic allograft nephropathy (CAN), we reasoned that expression of Par1/Emk1 could be altered in kidney allografts undergoing CAN. In this paper, we have analysed the association among renal allograft lesions and expression of Par1/Emk1, studied by RT-PCR on total RNA from 51 protocol biopsies of transplanted kidneys, five normal kidneys, and five dysfunctional allografts. The most significant result obtained has been the detection of alterations in the normal pattern of alternative splicing of the Par1/Emk1 transcript, alterations that included loss of expression of constitutively expressed isoforms, and the inclusion of a cryptic exon to generate a new Emk1 isoform (Emk1C). Expression of Emk1C was associated with an increase in the extension of the interstitial infiltrate (0.88+/-0.33 in Emk1C([+]) vs. 0.41+/-0.50 in Emk1C([-]); P<0.011), and with a trend to display higher interstitial scarring (0.66+/-0.70 vs. 0.29+/-0.52; P=0.09) in protocol biopsies when evaluated according to the Banff schema. Moreover, a higher mean arterial pressure (MAP) was also observed (110+/-11 vs. 99+/-11 mm Hg; P=0.012). From these results we propose that Par1/Emk1 could have a role in the development of CAN in kidney allografts.
authors.affiliation: Centre d'Oncologia Molecular, Institut de Recerca Oncológica (COM-IRO), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Barcelona E08907, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Hueso
authors.forename: Violeta
authors.initials: V
authors.lastname: Beltran
authors.forename: Francesc
authors.initials: F
authors.lastname: Moreso
authors.forename: Eva
authors.initials: E
authors.lastname: Ciriero
authors.forename: Xavier
authors.initials: X
authors.lastname: Fulladosa
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Grinyó
authors.forename: Daniel
authors.initials: D
authors.lastname: Serón
authors.forename: Estanis
authors.initials: E
authors.lastname: Navarro
mesh_terms: D000328:Adult; D017398:Alternative Splicing / Q000235:genetics*; D001706:Biopsy; D005091:Exons / Q000235:genetics; D005260:Female; D006801:Humans; D007249:Inflammation / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D007668:Kidney / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D016030:Kidney Transplantation; D008297:Male; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014184:Transplantation, Homologous
chemical_list: D020033:Protein Isoforms; D012333:RNA, Messenger; C094670:MARK2 protein, human; D017346:Protein Serine-Threonine Kinases