The phosphatase PRL-3 affects intestinal homeostasis by altering the crypt cell composition

Expression of the phosphatase of regenerating liver-3 (PRL-3) is known to promote tumor growth in gastrointestinal adenocarcinomas, and the incidence of tumor formation upon inflammatory events correlates with PRL-3 levels in mouse models. These carcinomas and their onset are associated with the impairment of intestinal cell homeostasis, which is regulated by a balanced number of Paneth cells and Lgr5 expressing intestinal stem cells (Lgr5+ ISCs). Nevertheless, the consequences of PRL-3 overexpression on cellular homeostasis and ISC fitness in vivo are unexplored. Here, we employ a doxycycline-inducible PRL-3 mouse strain to show that aberrant PRL-3 expression within a non-cancerous background leads to the death of Lgr5+ ISCs and to Paneth cell expansion. A higher dose of PRL-3, resulting from homozygous expression, led to mice dying early. A primary 3D intestinal culture model obtained from these mice confirmed the loss of Lgr5+ ISCs upon PRL-3 expression. The impaired intestinal organoid formation was rescued by a PRL inhibitor, providing a functional link to the observed phenotypes. These results demonstrate that elevated PRL-3 phosphatase activity in healthy intestinal epithelium impairs intestinal cell homeostasis, which correlates this cellular mechanism of tumor onset with PRL-3-mediated higher susceptibility to tumor formation upon inflammatory or mutational events.

Key messages

? Transgenic mice homozygous for PRL-3 overexpression die early.

? PRL-3 heterozygous mice display disrupted intestinal self-renewal capacity.

? PRL-3 overexpression alone does not induce tumorigenesis in the mouse intestine.

? PRL-3 activity leads to the death of Lgr5+ ISCs and Paneth cell expansion.

? Impairment of cell homeostasis correlates PRL-3 action with tumor onset mechanisms.

     

TBX3 and TBX5 duplication: A family with an atypical overlapping Holt-Oram/ulnar-mammary syndrome phenotype

Holt-Oram syndrome (HOS) is a rare, autosomal dominant heart-hand syndrome caused by mutations in the TBX5 gene. A wide spectrum of TBX5 mutations have been reported previously, most resulting in a null allele leading to haploinsufficiency. TBX5 gene duplications have been previously reported in association with typical and atypical HOS phenotypes. Ulnar-Mammary syndrome (UMS) is a distinct rare, autosomal dominant condition caused by mutations in the TBX3 gene. TBX5 and TBX3 are physically linked in cis on human chromosome 12 and contiguous chromosome 12q24 deletions comprising both TBX5 and TBX3 genes have been previously reported but to our knowledge, duplications have never been described. We report on a large German family with at least 17 affected individuals over 6 generations bearing a duplication at 12q24.21 identified on array-CGH comprising both TBX5 and TBX3 genes. Affected patients are presenting with HOS and UMS symptoms, consisting of variable limb anomalies involving the radial and the ulnar rays and cardiac findings such as congenital heart defects, persistent arterial duct or aortic stenosis, and non-classical symptoms, such as supernumerary nipples and cardiomyopathy. Fluorescence in situ hybridisation confirmed a tandem duplication at the 12q24.21 locus. This is the first report of a contiguous TBX3/TBX5 duplication associated with HOS/UMS phenotype.     

Osteopontin expression correlates with nuclear factor-κB activation and apoptosis downregulation in clear cell renal cell carcinoma

Osteopontin (OPN) is a phosphoglycoprotein implicated in tumorigenesis and tumor cell metastasis. Apoptosis inhibition is one of the mechanisms that contribute to development and progression of cancer, and might be initiated by OPN interaction with tumor cells. The aim of this study was to analyze the relation between OPN and nuclear factor-kappa B (NF-κB) expression in clear cell renal cell carcinoma (CCRCC), as well as their relation to apoptotic activity of tumor cells.Expression of OPN protein and p65 NF-κB subunit was analyzed immunohistochemically in 87 CCRCC samples, and compared mutually and with apoptotic index. Expression of OPN mRNA was analyzed using quantitative real-time PCR and compared with OPN and NF-κB protein expression in 22 CCRCC samples.Statistical analysis showed an association of p65 NF-κB with OPN mRNA (p = 0.015) and protein (p < 0.001). Also, we found an inverse relationship of OPN with NF-κB protein expression and apoptotic activity of tumor cells (p = 0.006 and p = 0.022, respectively). Our results indicate that p65 NF-κB signaling pathway may be involved in OPN-mediated CCRCC progression, partly by protecting tumor cells from apoptosis. Therefore, both molecules can constitute potential targets for therapeutic intervention in CCRCC.     

Pulmonary lymphomatoid granulomatosis in Griscelli syndrome type 2

Griscelli syndrome type 2 (GS2) is a rare autosomal-recessive disorder associated with a RAB27A gene mutation, and clinically manifesting as hypopigmentation, disseminated chronic encephalitis, and severe immunological disorders characterized by an accelerated hematological phase, also referred to as hemophagocytic syndrome (HS), or hemophagocytic lymphohistiocytosis (HLH). The authors report the diagnosis of GS2 in an 11-year-old girl with hypopigmentation, immunodeficiency, hepatosplenomegaly, severe neurological impairments, and fatal multiorgan failure. In this patient a diagnosis of pulmonary lymphomatoid granulomatosis (LG), an Epstein-Barr virus (EBV)-related lymphoproliferative disorder, was established from radiological and histological findings. Although EBV-related malignancies are common in immunocompromised patients, this is the first report of a diagnosis of pulmonary LG in a patient with GS2.     

Hepatitis C virus genotypes in 1,504 patients in Slovenia, 1993–2007

In order to identify the main routes of hepatitis C (HCV) transmission and to determine the HCV genotype distribution and its dynamics during a 15‐year period in Slovenia, HCV genotypes were detected using the INNO‐LiPA HCV II (Innogenetics) test for serum samples obtained from 1,504 patients representing 72.6% of all patients with chronic hepatitis C diagnosed from 1993 to 2007. HCV genotype 1 was predominant (56%), followed by genotypes 3, 2, and 4, with a prevalence of 37.8%, 5%, and 1.2%, respectively. HCV genotypes 5 and 6 were not detected in any patient. Patients infected with HCV genotype 3 were significantly younger (mean age 28.9 ± 8.5 years) than those infected with genotype 1 (mean age 38.9 ± 14.8 years; P < 0.0001) and those infected with HCV genotype 2 (mean age 50.3 ± 18.2 years; P < 0.0001). Intravenous drug use was identified as the most frequent possible HCV transmission route (34.3%), followed by medical‐related transmission such as transfusion of HCV‐contaminated blood or blood products, and hemodialysis (12.5%). Being an intravenous drug user was found to be strongly associated with HCV genotype 3 (OR, 3.71 [95% CI, 2.97–4.65]; P < 0.0001) and reporting infection by transfusion of blood or blood products was found to be strongly associated with HCV genotype 1 (OR, 3.28 [95% CI, 2.18–4.95]; P < 0.0001). During the 15‐year period, the proportion of genotype 3 increased substantially, reflecting the fact that the HCV epidemic in Slovenia is driven mostly by intravenous drug use. J. Med. Virol. 81:634–639, 2009 © 2009 Wiley‐Liss, Inc.     

Deep brain stimulation in the globus pallidus compensates response inhibition deficits: evidence from pantothenate kinase-associated neurodegeneration

Fronto-striatal loops are important for many cognitive control processes, like response inhibition, and it has been suggested that the globus pallidus is of particular importance for these processes. In the current study, we investigate the effect of deep brain stimulation in the GP on response inhibition processes by means of neurophysiological (EEG) methods. We perform a case–control study in neuroaxonal dystrophy pantothenate kinase-associated neurodegeneration (PKAN) using single-case statistics. We control the signal-to-noise ratio of the EEG data. The data show that disease-related changes in the globus pallidus lead to dysfunctions in response inhibition processes. Dysfunctions in the GP seem to affect controlled, but not automatized behavior as evidenced by an increased rate of false alarms and attenuation of inhibition-related neurophysiological correlates. With respect to controlled behavior in terms of response inhibition, it seems that pre-motor subprocesses and not evaluation subprocesses are affected. Deep brain stimulation in the globus pallidus seems to be able to compensate the effects of disease-related changes in this structure and normalizes response inhibition performance and their electrophysiological correlates in PKAN.     

Anti-beta(2)-glycoprotein I antibodies in children with atopic dermatitis

beta(2)-Glycoprotein I (beta(2)GPI) appears to be the major antigen for antiphospholipid antibodies (aPL) in patients with antiphospholipid syndrome (APS). In early infancy, virtually all children initiate transient immune response to non-pathogenic nutritional antigens, which fails to terminate in children with atopic diseases. To examine the possibility that a prolonged immune response to beta(2)GPI could also spread to the human protein, antibodies against human beta(2)GPI (anti-beta(2)GPI) were determined in 93 randomly selected children with different allergic diseases. A high frequency (42%) of IgG anti-beta(2)GPI was found in children with atopic dermatitis (AD), but not in those with other allergic diseases. Anti-beta(2)GPI in children with AD were exclusively of the IgG1 subclass and bound to bovine beta(2)GPI as well, but not to either beta(2)GPI combined with the phospholipid cardiolipin. The epitopes were identified in domain V of beta(2)GPI and the antibody binding was abolished upon the specific proteolytic cleavage of the phospholipid-binding C-terminal loop in domain V of beta(2)GPI. These results indicated that the epitopes for anti-beta(2)GPI in children with AD most likely resided in close vicinity of the phospholipid-binding site of beta(2)GPI. The epitopic difference from anti-beta(2)GPI in APS may explain presumed non-thrombogenicity of anti-beta(2)GPI in children with AD.     

Executive Functions in Preschool Children With ADHD and DBD: An 18-Month Longitudinal Study

In this longitudinal study, we examined the stability of the association between executive functions and externalizing behavior problems, and the developmental change of executive functions in a predominately clinically diagnosed preschool sample (N = 200). Inhibition and working memory performance were assessed three times in 18 months. Across time, poorer inhibition performance in young children was associated with attention deficit hyperactivity disorder (ADHD) and disruptive behavior disorders (DBD), and poorer working memory performance was associated with ADHD. Inhibition and working memory performance increased over time, especially in the early preschool period. The improvement of inhibition performance was more pronounced in the clinically diagnosed children compared to the TD children.