Amyloid Beta Peptides Affect Pregnenolone and Pregnenolone Sulfate Levels in PC-12 and SH-SY5Y Cells Depending on Cholesterol

Increased amyloid beta (AB) peptide concentration is one of the initiating factors in the neurodegeneration process. It has been suggested that cholesterol induces the synthesis of AB peptide from amyloid precursor protein or facilitates the formation of amyloid plaque by lowering the aggregation threshold of the peptide. It is also shown that AB peptides may affect cholesterol metabolism and the synthesis of steroid hormones such as progesterone and estradiol. Pregnenolone (P) and pregnenolone sulfate (PS) are the major steroids produced from cholesterol in neural tissue. In toxicity conditions, the effect of AB peptides on P and PS levels has not yet been determined. Furthermore, it has not been clearly defined how changes in cellular P and PS levels affect neuronal cell survival. The aim of this study was to determine the effects of AB peptides on cellular changes in P and PS levels depending on the level of their main precursor, cholesterol. Cholesterol and toxic concentrations of AB fragments (AB 25–35, AB 1–40 and AB 1–42) were applied to PC-12 and SH-SY5Y cells. Changes in cellular cholesterol, P and PS levels were determined simultaneously in a dose—and time-dependent manner. The cell viability and cell death types were also evaluated. AB peptides affected both cell viability and P/PS levels. Steroid levels were altered depending on AB fragment type and the cholesterol content of the cells. Treatment with each of the AB fragments alone increased P levels by twofold. However, combined treatment with AB peptides and cholesterol increased P levels by approximately sixfold, while PS levels were increased only about 2.5 fold in both cell lines. P levels in the groups treated with AB 25–35 were higher than those in AB 1–40 and AB 1–42 groups. The cell viabilities were significantly low in the group treated by AB and cholesterol (9 mM). The effect of AB peptides on P levels might be a result of cellular self-defense. On the other hand, the rate of P increase might be playing a key role in the cell death mechanism of AB toxicity depending on cellular cholesterol levels.     

Cytogenetic characterization of ataxia telangiectasia (AT) heterozygotes using lymphoblastoid cell lines and chronic γ-irradiation

Summary Lymphoblastoid cell lines (LCLs) derived from two patients identified as ataxia telangiectasia (AT), two obligate AT heterozygotes and two controls (healthy subjects with no known genetic disease or relationship to AT patients) were compared with respect to the induction of chromosomal breaks by acute and chronic -irradiation. Although there was a considerable increase in the frequency of chromosomal breaks per cell in the LCLs of AT patients resulting from acute irradiation, the small increase occurring in the LCLs of the AT heterozygotes made it difficult to distinguish them from the controls. Following chronic -irradiation, however, the frequency of chromosomal breaks per cell in the LCLs of the AT heterozygotes occupied a significantly distinct position from that of the controls. These observations suggested that the use of chronic irradiation may be a better choice in the cytogenetic characterization of AT heterozygotes.     

Management of cytological material,pre‐analytical procedures and bio‐banking in effusion cytopathology

Serous effusion fluid is one of the most commonly encountered specimens in routine cytopathology practice. It provides invaluable information about the patient and the clinical status; but to get the most of it, specimen handling and processing must be carried out properly. Cytomorphology is the basis of a successful analysis which should complemented by ancillary tests when needed. A wide spectrum of ancillary techniques ‐ ranging from immunocytochemistry and flow cytometry to different assays of molecular pathology ‐ can be applied to serous effusions. This article describes the acquisition and management of serous effusion fluids, methods for preservation and transportation, different techniques of cytopreparation, application of immunocytochemistry, flow cytometry, and fluorescence in‐situ hybridization (FISH), as well as DNA extraction for polymerase chain reaction (PCR) and next generation sequencing (NGS). Principles of bio‐banking of effusion samples are also discussed which is getting more important in correlation with the developments in personalized medicine.     

Changes in the expression levels of CB1 and GLP‐1R mRNAs and microRNAs 33a and 122 in the liver of type 2 diabetic rats treated with ghrelin

The aim of the study is to clarify the effect of ghrelin treatment on the messenger RNA (mRNA) expression of the cannabinoid receptor 1 (Cnr1/CB1) and glucagon‐like peptide 1 receptor (Glp1r/GLP‐1R) as well as microRNAs (miR)‐122 and miR‐33a in the liver of rats with type 2 diabetes mellitus (T2DM). Adult Sprague‐Dawley rats were divided into three groups: control (n = 7), T2DM (n = 7), and treatment (n = 7). Control animals received tap water. T2DM was induced by feeding 10% fructose in drinking water for 2 weeks followed by a single injection of streptozotocin (40 mg/kg, intraperitoneally [IP]). In the treatment group, diabetic rats were injected ghrelin (25 μg/kg, IP) for 14 days. Serum lipid profiles were evaluated, and mRNA expression levels of Cnr1 and Glp1r in the liver were detected using quantitative real‐time polymerase chain reaction (RT‐qPCR). In addition, miR‐122 and miR‐33a levels were measured using RT‐qPCR. Serum triglycerides, low‐density lipoprotein cholesterol, and very‐low‐density lipoprotein cholesterol significantly increased in the T2DM group compared with control rats but ghrelin treatment showed no effect on serum lipid levels. The mRNA expression levels of Cnr1 and Glp1r decreased in the T2DM group compared with the control group. These reductions were significantly increased in the T2DM group treated with ghrelin. Furthermore, the increase in miR‐33a expression level was reduced in the treatment group compared to rats with T2DM. Our findings suggested that ghrelin treatment may alter the mRNA expression levels of CB1 and GLP‐1R in the liver of rats with T2DM. The mRNA levels of Cnr1 and Glp1r may inversely correlate with the expression level of miR‐33a but not miR‐122.     

A novel mutation in FGFR3 causes camptodactyly, tall stature, and hearing loss (CATSHL) syndrome

Activating mutations of FGFR3, a negative regulator of bone growth, are well known to cause a variety of short-limbed bone dysplasias and craniosynostosis syndromes. We mapped the locus causing a novel disorder characterized by camptodactyly, tall stature, scoliosis, and hearing loss (CATSHL syndrome) to chromosome 4p. Because this syndrome recapitulated the phenotype of the Fgfr3 knockout mouse, we screened FGFR3 and subsequently identified a heterozygous missense mutation that is predicted to cause a p.R621H substitution in the tyrosine kinase domain and partial loss of FGFR3 function. These findings indicate that abnormal FGFR3 signaling can cause human anomalies by promoting as well as inhibiting endochondral bone growth.