Generation of induced Pluripotent Stem Cells as disease modelling of NLSDM.

Neutral Lipid Storage Disease with Myopathy (NLSDM) is a rare defect of triacylglycerol metabolism, characterized by the abnormal storage of neutral lipid in organelles known as lipid droplets (LDs). The main clinical features are progressive myopathy and cardiomyopathy. The onset of NLSDM is caused by autosomal recessive mutations in the PNPLA2 gene, which encodes adipose triglyceride lipase (ATGL). Despite its name, this enzyme is present in a wide variety of cell types and catalyzes the first step in triacylglycerol lipolysis and the release of fatty acids. Here, we report the derivation of NLSDM-induced pluripotent stem cells (NLSDM-iPSCs) from fibroblasts of two patients carrying different PNPLA2 mutations. The first patient was homozygous for the c.541delAC, while the second was homozygous for the c.662G>C mutation in the PNPLA2 gene. We verified that the two types of NLSDM-iPSCs possessed properties of embryonic-like stem cells and could differentiate into the three germ layers in vitro. Immunofluorescence analysis revealed that iPSCs had an abnormal accumulation of triglycerides in LDs, the hallmark of NLSDM. Furthermore, NLSDM-iPSCs were deficient in long chain fatty acid lipolysis, when subjected to a pulse chase experiment with oleic acid. Collectively, these results demonstrate that NLSDM-iPSCs are a promising in vitro model to investigate disease mechanisms and screen drug compounds for NLSDM, a rare disease with few therapeutic options.

Prevalence of mutations in LEP, LEPR, and MC4R genes in individuals with severe obesity.

Obesity is a major public health concern; despite evidence of high heritability, the genetic causes of obesity remain unclear. In this study, we assessed the presence of mutations in three genes involved in the hypothalamic leptin-melanocortin regulation pathway (leptin, LEP; leptin receptor, LEPR; and melanocortin-4 receptor, MC4R), which is important for energy homeostasis in the body, in a group of patients with severe obesity. For this study, we selected 77 patients who had undergone bariatric surgery and had a pre-operative body mass index (BMI) >35 kg/m2, early onset and a family history of being overweight. Candidate genes were screened by direct sequence analysis to search for rare genetic variations. The common LEP -2548 G/A polymorphism was also evaluated for its influence on the BMI (in obesity patients) and for obesity risk, using a case-control study involving 117 healthy individuals. Two different non-synonymous alterations in MC4R were found in two patients: the p.(Thr112Met), previously described in the literature as a probable gene involved in the obesity phenotype, and the novel p.(Tyr302Asp) variant, predicted to be pathogenic by in silico evaluations and family segregation studies. The LEP -2548 G/A polymorphism was not associated with the BMI or obesity risk. In conclusion, we have reported a novel mutation in MC4R in a family of Italian patients with severe obesity. Screening for MC4R could be important for directing the carriers of mutations towards therapy including partial agonists of the MC4R that could normalize their appetite and inhibit compulsive eating. Next-generation sequencing could be used to clarify the genetic basis of obesity in the future.

Chanarin Dorfman syndrome: a case report with novel nonsense mutation.

Chanarin Dorfman syndrome (CDS) is a very rare neutral lipid metabolism disorder with multisystem involvement. It is inherited as an autosomal recessive manner. It is characterized with congenital ichthyosiform erythroderma and involvement of liver, muscle, and central nervous system. Demonstration of lipid vacuoles in neutrophils from peripheral blood smears in patients with ichthyosiform erythroderma leads to the diagnosis. We report a novel ABHD5 truncating variant in a twenty nine month old female child, who presented with icthyosiform erythroderma.

A new splicing site mutation of the ABCB4 gene in intrahepatic cholestasis of pregnancy with raised serum gamma-GT.

BACKGROUND: Intrahepatic cholestasis of pregnancy is a liver disorder with a multifactorial etiology characterized by maternal pruritus, abnormal liver function tests and increased fetal risk. The main biochemical finding is the increase in total serum bile acid concentrations. In a subgroup of women, the serum gamma-glutamyl transpeptidase level is also increased. There is evidence that dysfunction of the ABCB4 gene might play a role in intrahepatic cholestasis of pregnancy development. AIM: To investigate the role of the ABCB4 gene in Italian women with intrahepatic cholestasis of pregnancy and raised gamma-glutamyl transpeptidase by, analyzing the complete coding sequence and mRNA splicing products. METHODS: Among 299 women with intrahepatic cholestasis of pregnancy, 10 showing raised gamma-glutamyl transpeptidase were enrolled in this study. DNA and RNA were extracted from peripheral blood mononuclear cells using standard procedures. The 27 coding exons and the promoter region were amplified by polymerase chain reaction and analyzed by sequencing. Reverse transcript-polymerase chain reaction analysis of ABCB4 mRNA and cDNA analysis were also performed. RESULTS: A novel splicing mutation that causes a truncated protein of 249 amino acid was identified in a woman who had the highest serum levels of gamma-glutamyl transpeptidase, alkaline phosphatase, bile acids, and the highest pruritus score. We identified also one already described p.R590Q mutation in a woman who had significantly higher serum levels of alkaline phosphatase, aspartate, and alanine aminotransferase. CONCLUSIONS: Our study demonstrates that splicing mutations in the ABCB4 gene can cause ICP in women with high gamma-glutamyl transpeptidase and thus a complete analysis of coding sequence and cDNA products is required.

Androgen receptor mRNA under-expression in poorly differentiated human hepatocellular carcinoma.

Many studies suggest that hepatocellular carcinoma (HCC) is an androgen-dependent tumor with an incidence five times higher in males, but few data are available on the androgen receptor (AR) mRNA levels in different physiological classes of human liver specimens. In this study 108 human hepatic samples have been analyzed for AR mRNA expression by a comparative RT-PCR assay. These consisted of 35 non-tumoral hepatic samples (3 normal parenchymas, 4 steatosis, 10 hepatitis, 18 cirrhosis), 38 tumoral specimens derived from uninodular and multinodular HCCs and 35 peritumoral hepatic tissues. Normalized AR mRNA levels in tumoral and peritumoral liver tissues spanned from 0 to 146% and from 7 to 125% respectively. Only in a relatively small percentage of HCCs, the levels of expression of AR mRNA were higher than in the corresponding peritumoral tissues (16% of total HCCs). Although extremely variable, the AR mRNA levels were related to histological tumoral differentiation and proved to be lower in the highly dedifferentiated HCCs as compared to the well differentiated ones. Therefore, the evaluation of AR expression in HCC patients might be relevant for the planning of clinical studies on anti-androgen therapies, which might be useful only in the cases in which a high level of AR mRNA is detected, considering the high heterogeneity of AR mRNA levels which characterizes HCC samples. It is likely that the HCCs, expressing low or undetectable levels of AR mRNA, would not benefit by the anti-androgen therapy.

u-PA and c-MET mRNA expression is co-ordinately enhanced while hepatocyte growth factor mRNA is down-regulated in human hepatocellular carcinoma.

Hepatocyte growth factor/scatter factor (HGF/SF) is one of the most important humoral mediators of liver regeneration. It is potentially related to molecular mechanisms of hepatocarcinogenesis via a paracrine system involving its cellular receptor, c-met. In this study, the expression patterns of HGF and c-met were evidenced by multiplex RT-PCR in different specimens of human hepatic tissues (n = 71). A significant increase of c-met mRNA expression was detected in hepatitis (P = 0.001), cirrhosis (P = 0.006), and hepatocellular carcinoma (HCC) tissue (P = 0.003) compared with normal parenchyma and steatosis. HGF mRNA expression was significantly higher only in hepatitis (P = 0.01). Over-expression of c-met mRNA and under-expression of HGF mRNA were detected in the HCCs compared with the corresponding peri-tumoral tissues. Neither HGF nor c-met expression was related to age, sex, tumor size, grading, presence of pseudocapsula, and proliferative activity of the malignant hepatocytes. A significant inverse correlation was found between c-met mRNA expression level and survival (in months) of patients (P = 0.007), as previously shown for urokinase-type plasminogen activator (u-PA) mRNA (P = 0.027). In addition, c-met mRNA expression was strictly associated with u-PA mRNA level in HCC samples (P = 0.001). These data show that a loss of balance concerning HGF, c-met, and u-PA mRNA expression occurs during hepatocarcinogenesis. Particularly, up-regulation of c-met and u-PA mRNA transcription appears to be coordinately regulated, and their levels of expression are inversely correlated with survival; they must therefore play an important role in the development and progression of human HCC and may also be relevant prognostic markers.

Gene response of human skin fibroblasts to urokinase- and tissue-type plasminogen activators.

In a previous work we have reported evidences on the mitogenic activity of urokinase-type and tissue-type plasminogen activator (u-PA, t-PA) on serum-deprived human dermal fibroblasts. In this work we have studied the transcription-dependent changes of some cell-cycle related genes associated with the biological activity of PAs, as well as the possible involvement of protein tyr kinases (PTK) and/or protein kinase C (PKC) in the mitogenic signal transduction. The data obtained demonstrate that the growth factor activity of PAs is associated with: - a rapid transient activation of early response genes, c-fos, c-jun and c-myc; - the subsequent coordinated down-regulation of p53 and p21CIP1; - the constant expression of the MEK1 mRNA in every phase of the cell cycle. Quiescent (G0) cells did not express c-fos, c-jun, c-myc and cyclin A, but upon stimulation with mitogens (fetal calf serum (FCS), u-PA, t-PA) the cyclin A mRNA expression was observed in concomitance with the activation of DNA synthesis. Therefore u-PA, t-PA and FCS similarly modulate the expression of c-fos, c-jun, c-myc, p53, p21CIP1 and cyclin A with only slight differences likely related to the time required for activation of DNA synthesis. The PAs mitogenic stimulation of serum-starved cells was associated with the internalization of their molecules, as revealed by immunostaining. The biological activity of u-PA, t-PA, as well as that of limiting concentration of FCS (1%), was mediated by PTK and PKC. Conversely, PTK, but not PKC, was involved in the activation of the proliferative response of basic fibroblast growth factor in the same experimental conditions. In conclusion, u-PA and t-PA can utilize two different pathways, one depending on PTK and the other on PKC in a way similar to the mitogenic activity induced by low concentration of FCS (1%).

Quantitative in situ hybridization for the evaluation of gene expression in asynchronous and synchronized cell cultures and in tissue sections.

We describe an image analysis (IA) system that has been applied for the quantitative evaluation of mRNAs evidenced by in situ hybridization (ISH) with radiolabelled probes in cultured cells and in tissue sections. The ISH-IA method was used for the evaluation of cultured cell morphological parameters such as cell and nucleous area (CA and NA, respectively) in parallel with the levels of mRNAs detected as hybridization grains areas (GA). The evaluation of these parameters, together with the analysis of the levels of mRNAs (c-jun, cyclin A) specific for given cell cycle phases (i.e. G1 and S/G2), allowed the identification, in asynchronous cultures of human skin fibroblasts, of cells in G1 and S/G2 phases. The mRNA levels measured by ISH-AI were comparable with those detected by RT-PCR. This method was also applied for the analysis of fibronectin (FN) gene expression in control skin fibroblasts in relationship with the different phases of the cell cycle and in comparison with a tumor cell line (Sk-Hep1), heterogeneous either for morphometric parameters or for the levels of this transcript. Finally, the ISH-AI was applied for the semiquantitative evaluation of the expression, localization and alternative splicing pattern of FN mRNA in normal liver and in hepatocellular carcinoma (HCC) tissue sections.

Expression of urokinase-type plasminogen activator (u-PA), u-PA receptor, and tissue-type PA messenger RNAs in human hepatocellular carcinoma.

Expression of plasminogen activators (PAs) and urokinase-type PA receptor (u-PAR) is associated with tumor growth and invasion. For in vivo human tumor tissues, there is no information on gene expression of PAs in hepatocellular carcinoma (HCC) or other hepatic pathophysiological conditions. In this study we examined the relative levels of u-PA, tissue-type PA (t-PA), and u-PAR mRNA expression in human HCC by reverse transcription-PCR compared with those expressed in peritumoral hepatic tissues. Twenty-five of 25 HCCs expressed u-PA mRNA, as well as 16 of 25 hepatic peritumoral tissues. However, none of the 14 cases of nontumorous liver samples (i.e., normal parenchyma, steatosis, and nonspecific reactive and chronic hepatitis) showed detectable levels of u-PA mRNA. The same samples analyzed for uPAR and t-PA mRNAs exhibited higher levels of these mRNAs in the malignant tissues compared with nontumorous ones. A strong correlation was found between the relative levels of u-PA and t-PA mRNAs detected in the tumor and in the corresponding peritumoral tissues (P < 0.001 for u-PA; P < 0.02 for t-PA). However, there was no correlation between the expression of u-PA and t-PA in HCC (P = 0.565). Furthermore, a significant inverse correlation was found between survival months of male patients and the relative level of u-PA mRNA (P < 0.05) detected at the time of biopsy, whereas no correlation was found in the case of t-PA mRNA. These results are in line with the possible differential biological role of u-PA and t-PA in the tumor etiopathogenesis and suggest that the detection of relative levels of u-PA mRNA may be a useful prognostic factor for male HCC patients.

RT-PCR detection of fibronectin EDA+ and EDB+ mRNA isoforms: molecular markers for hepatocellular carcinoma.

Alternative splicing of fibronectin pre-mRNA has been shown to be independently regulated at the EDA and EDB regions in a tissue and developmental stage-specific manner. In this study, RT-PCR approaches were developed for the detection of EDA and EDB FN mRNA isoforms in hepatocarcinoma cells (SK-Hep-I) grown in vitro and in human liver biopsies. While EDA+ and EDB+ isoforms were not present in control adult liver, they were detectable in the hepatocarcinoma cells and in fetal liver. The RT-PCR analysis, extended to biopsies of malignant and non-malignant hepatic tissues, showed that FN mRNAs containing the EDA and EDB sequences were present in the 14 hepatocellular carcinomas (HCCs) tested but absent in the non-tumorous liver tissues (i.e., normal parenchyma, non-specific reactive and chronic hepatitis, steatosis). The EDB+ FN mRNA isoforms were also detected in 3 cases of benign neoplasm (hepatocellular adenoma, HCA, I; nodular focal hyperplasia, NFH, 2), while the EDA+ was only detectable in I of the 2 cases of NFH. In addition, both EDA+ and EDB+ isoforms were expressed in 5 out of 9 cirrhotic livers surrounding the tumors. This molecular analysis, which can also be performed on small liver biopsies (2 mg), may therefore be a useful additional tool in the diagnosis of HCC.