49 research outputs found
Kidney growth in normal and diabetic mice is not affected by human insulin-like growth factor binding protein-1 administration
Insulin-like growth factor I (IGF-I) accumulates in the kidney following
the onset of diabetes, initiating diabetic renal hypertrophy. Increased
renal IGF-I protein content, which is not reflected in messenger RNA
(mRNA) levels, suggests that renal IGF-I accumulation is due to
sequestration of circulating IGF-I rather than to local synthesis. It has
been suggested that IGF-I is trapped in the kidney by IGF binding protein
1 (IGFBP-1). We administered purified human IGFBP-1 (hIGFBP-1) to
nondiabetic and diabetic mice as three daily sc injections for 14 days,
starting 6 days after induction of streptozotocin diabetes when the
animals were overtly diabetic. Markers of early diabetic renal changes
(i.e., increased kidney weight, glomerular volume, and albuminuria)
coincided with accumulation of renal cortical IGF-I despite decreased mRNA
levels in 20-day diabetic mice. Human IGFBP-1 administration had no effect
on increased kidney weight or albuminuria in early diabetes, although it
abolished renal cortical IGF-I accumulation and glomerular hypertrophy in
diabetic mice. Increased IGF-I levels in kidneys of normal mice receiving
hIGFBP-1 were not reflected on kidney parameters. IGFBP-1 administration
in diabetic mice had only minor effects on diabetic renal changes.
Accordingly, these results did not support the hypothesis that IGFBP-1
plays a major role in early renal changes in diabetes
The role of the IGF axis in IGFBP-1 and IGF-I induced renal enlargement in Snell dwarf mice
Insulin-like growth factor (IGF) binding protein-1 (IGFBP-1) is generally
believed to inhibit IGF action in the circulation. In contrast, IGFBP-1
has been reported to interact with cell surfaces and enhance IGF-I action
locally in some tissues. Renal IGFBP-1 levels are found elevated in
various conditions characterized by renal growth (e.g. diabetes mellitus,
hypokalemia). To test whether IGFBP-1 is a renotropic factor, IGFBP-1 was
administered alone or in combination with IGF-I to Snell dwarf mice, an in
vivo model without compensatory feedback effects on growth hormone (GH)
secretion. In three control groups of Snell dwarf mice, placebo, GH or
IGF-I was administered. Compared with placebo, kidney weight increased in
all treated groups, however, with different effects on kidney morphology.
Administration of IGF-I, alone or in combination with IGFBP-1, tended to
increase glomerular volume, while no changes were seen in the other
groups. Administration of IGFBP-1 or IGFBP-1+IGF-I both caused dilatation
of the thin limbs of Henle's loop, while GH or IGF-I administration had no
visible effect. Furthermore, IGF-I administration resulted in an increased
mean number of nuclei per cortical area and renal weight, whereas GH,
IGF-I+IGFBP-1 or IGFBP-1 caused a decreased renal nuclei number. In situ
hybridization and immunohistochemistry showed specific changes of the
renal IGF system expression patterns in the different groups.
Particularly, IGFBP-1 administration resulted in extensive changes in the
mRNA expression of the renal IGF system, whereas the other administration
regimen resulted in less prominent modifications. In contrast,
administration of IGFBP-1 and IGFBP-1+IGF-I resulted in identical changes
in the protein expression of the renal IGF system. Our results indicate
that IGFBP-1, alone or in combination with IGF-I, demonstrated effects on
the renal tubular system that differ from the effects of IGF-I
A multi-exon deletion within WWOX is associated with a 46,XY disorder of sex development
Disorders of sex development (DSD) are congenital conditions where chromosomal, gonad or genital development is atypical. In a significant proportion of 46,XY DSD cases it is not possible to identify a causative mutation, making genetic counseling difficult and potentially hindering optimal treatment. Here, we describe the analysis of a 46,XY DSD patient that presented at birth with ambiguous genitalia. Histological analysis of the surgically removed gonads showed bilateral undifferentiated gonadal tissue and immature testis, both containing malignant germ cells. We screened genomic DNA from this patient for deletions and duplications using an Illumina whole-genome SNP microarray. This analysis revealed a heterozygous deletion within the WWOX gene on chromosome 16, removing exons 6-8. Analysis of parental DNA showed that the deletion was inherited from the mother. cDNA analysis confirmed that the deletion maintained the reading frame, with exon 5 being spliced directly onto exon 9. This deletion is the first description of a germline rearrangement affecting the coding sequence of WWOX in humans. Previously described Wwox knockout mouse models showed gonadal abnormalities, supporting a role for WWOX in human gonad development
Prevalence of c-KIT Mutations in Gonadoblastoma and Dysgerminomas of Patients with Disorders of Sex Development (DSD) and Ovarian Dysgerminomas
Activating c-KIT mutations (exons 11 and 17) are found in 10-40% of testicular seminomas, the majority being missense point mutations (codon 816). Malignant ovarian dysgerminomas represent ~3% of all ovarian cancers in Western countries, resembling testicular seminomas, regarding chromosomal aberrations and c-KIT mutations. DSD patients with specific Y-sequences have an increased risk for Type II Germ Cell Tumor/Cancer, with gonadoblastoma as precursor progressing to dysgerminoma. Here we present analysis of c-KIT exon 8, 9, 11, 13 and 17, and PDGFRA exon 12, 14 and 18 by conventional sequencing together with mutational analysis of c-KIT codon 816 by a sensitive and specific LightCycler melting curve analysis, confirmed by sequencing. The results are combined with data on TSPY and OCT3/4 expression in a series of 16 DSD patients presenting with gonadoblastoma and dysgerminoma and 15 patients presenting pure ovarian dysgerminomas without DSD. c-KIT codon 816 mutations were detected in five out of the total of 31 cases (all found in pure ovarian dysgerminomas). A synonymous SNP (rs 5578615) was detected in two patients, one DSD patient (with bilateral disease) and one patient with dysgerminoma. Next to these, three codon N822K mutations were detected in the group of 15 pure ovarian dysgerminomas. In total activating c-KIT mutations were found in 53% of ovarian dysgerminomas without DSD. In the group of 16 DSD cases a N505I and D820E mutation was found in a single tumor of a patient with gonadoblastoma and dysgerminoma. No PDGFRA mutations were found. Positive OCT3/4 staining was present in all gonadoblastomas and dysgerminomas investigated, TSPY expression was only seen in the gonadoblastoma/dysgerminoma lesions of the 16 DSD patients. This data supports the existence of two distinct but parallel pathways in the development of dysgerminoma, in which mutational status of c-KIT might parallel the presence of TSPY
A 46,XY female DSD patient with bilateral gonadoblastoma, a novel SRY missense mutation combined with a WT1 KTS splice-site mutation
Patients with Disorders of Sex Development (DSD), especially those with gonadal dysgenesis and hypovirilization are at risk of developing malignant type II germ cell tumors/cancer (GCC) (seminoma/dysgerminoma and nonseminoma), with either carcinoma in situ (CIS) or gonadoblastoma (GB) as precursor lesion. In 10-15% of 46,XY g
Variable loss of functional activities of androgen receptor mutants in patients with androgen insensitivity syndrome
Androgen receptor (AR) mutations in androgen insensitivity syndrome (AIS) are associated with a variety of clinical phenotypes. The aim of the present study was to compare the molecular properties and potential pathogenic nature of 8 novel and 3 recurrent AR variants with a broad variety of functional assays. Eleven AR variants (p.Cys177Gly, p.Arg609Met, p.Asp691del, p.Leu701Phe, p.Leu723Phe, p.Ser741Tyr, p.Ala766Ser, p.Arg775Leu, p.Phe814Cys, p.Lys913X, p.Ile915Thr) were analyzed for hormone binding, transcriptional activation, cofactor binding, translocation to the nucleus, nuclear dynamics, and structural conformation. Ligand-binding domain variants with low to intermediate transcriptional activation displayed aberrant Kd values for hormone binding and decreased nuclear translocation. Transcriptional activation data, FxxFF-like peptide binding and DNA binding correlated well for all variants, except for p.Arg609Met, p.Leu723Phe and p.Arg775Leu, which displayed a relatively higher peptide binding activity. Variants p.Cys177Gly, p.Asp691del, p.Ala766Ser, p.Phe814Cys, and p.Ile915Thr had intermediate or wild type values in all assays and showed a predominantly nuclear localization in living cells. All transcriptionally inactive variants (p.Arg609Met, p.Leu701Phe, p.Ser741Tyr, p.Arg775Leu, p.Lys913X) were unable to bind to DNA and were associated with complete AIS. Three variants (p.Asp691del, p.Arg775Leu, p.Ile915Thr) still displayed significant functional activities in in vitro assays, although the clinical phenotype was associated with complete AIS. The data show that molecular phenotyping based on 5 different functional assays matched in most (70%) but not all cases. Copyrigh