Osteogenesis imperfecta – molekularna osnova i lijekovi budućnosti

Osteogenesis imperfecta (OI) or brittle bone disease is a metabolic bone disease characterized by bone fragility, low bone mass, and increased rate of bone fractures and deformities. Clinical presentation in OI patients shows wide variability ranging from mild to severe and lethal OI types. Advances in molecular biology and studies on animal OI models found at least 16 new genes involved in OI pathogenesis. The majority of mutations are autosomal dominant aff ecting COL1A1 and COL1A2 genes responsible for collagen synthesis. The remaining 10%-15% of mutations in OI are autosomal recessive and aff ect genes involved in various metabolic bone processes. Progress in understanding bone metabolism and genetic engineering off ers new potential therapeutic opportunities that are under diff erent stages of investigation.Osteogenesis imperfecta (OI) ili bolest krhkih kostiju je metabolička bolest kostiju obilježena krhkim kostima, niskom koštanom masom i povišenom stopom lomova i deformiteta kostiju. Klinička prezentacija bolesnika s OI veoma je raznolika, od blagog do teškog i smrtonosnog tipa OI. Napretkom molekularne biologije i istraživanjima na životinjskim modelima OI nađeno je najmanje 16 novih gena uključenih u patogenezu OI. Većina mutacija su autosomno dominantne i zahvaćaju gene COL1A1 i COL1A2 koji su odgovorni za sintezu kolagena. Preostalih 10%-15% mutacija u OI su autosomno recesivne i zahvaćaju gene uključene u razne metaboličke procese u kostima. Sve bolje razumijevanje metabolizma kostiju i genetski inženjering nude nove potencijalne terapijske mogućnosti koje su u različitim fazama ispitivanja

Regulation of miR-146a by RelA/NFkB and p53 in STHdhQ111/HdhQ111 Cells, a Cell Model of Huntington's Disease

Huntington's disease (HD) is caused by the expansion of N-terminal polymorphic poly Q stretch of the protein huntingtin (HTT). Deregulated microRNAs and loss of function of transcription factors recruited to mutant HTT aggregates could cause characteristic transcriptional deregulation associated with HD. We observed earlier that expressions of miR-125b, miR-146a and miR-150 are decreased in STHdhQ111/HdhQ111 cells, a model for HD in comparison to those of wild type STHdhQ7/HdhQ7 cells. In the present manuscript, we show by luciferase reporter assays and real time PCR that decreased miR-146a expression in STHdhQ111/HdhQ111 cells is due to decreased expression and activity of p65 subunit of NFkB (RelA/NFkB). By reporter luciferase assay, RT-PCR and western blot analysis, we also show that both miR-150 and miR-125b target p53. This partially explains the up regulation of p53 observed in HD. Elevated p53 interacts with RelA/NFkB, reduces its expression and activity and decreases the expression of miR-146a, while knocking down p53 increases RelA/NFkB and miR-146a expressions. We also demonstrate that expression of p53 is increased and levels of RelA/NFkB, miR-146a, miR-150 and miR-125b are decreased in striatum of R6/2 mice, a mouse model of HD and in cell models of HD. In a cell model, this effect could be reversed by exogenous expression of chaperone like proteins HYPK and Hsp70. We conclude that (i) miR-125b and miR-150 target p53, which in turn regulates RelA/NFkB and miR-146a expressions; (ii) reduced miR-125b and miR-150 expressions, increased p53 level and decreased RelA/NFkB and miR-146a expressions originate from mutant HTT (iii) p53 directly or indirectly regulates the expression of miR-146a. Our observation of interplay between transcription factors and miRNAs using HD cell model provides an important platform upon which further work is to be done to establish if such regulation plays any role in HD pathogenesis

Genetic Differentiation of Appendiceal Tumor Malignancy: A Guide for the Perplexed

OBJECTIVE: To use differential gene expression of candidate markers to discriminate benign appendiceal carcinoids (APCs) from malignant and mixed cell APCs. SUMMARY BACKGROUND DATA: Controversy exists in regard to the appropriate surgical management of APCs since it is sometimes difficult to predict tumor behavior using traditional pathologic criteria. We have identified 5 differentially expressed genes (a mitosis-regulatory gene NAP1L1, an adhesin MAGE-D2, an estrogen-antagonist, the metastasis marker MTA1, the apoptotic marker NALP, and chromogranin A) that define gut neuroendocrine cell behavior. METHODS: Total RNA was isolated using TRIzol reagent from 42 appendiceal samples, including appendiceal carcinoids identified at exploration for appendicitis (no evidence of metastasis; n = 16), appendicitis specimens (n = 11), malignant appendiceal tumors (>1.5 cm, evidence of metastatic invasion; n = 7), and mixed (goblet) cell appendiceal adenocarcinoids (n = 3), normal appendiceal tissue (n = 5), and 5 colorectal cancers. Gene expression (CgA, NAP1L1, MAGE-D2, MTA1, and NALP1) was examined by Q-RT PCR (Applied Biosystems) and quantified against GAPDH. RESULTS: CgA message was elevated (>1000-fold, P < 0.05) in all tumor types. NAP1L1 was elevated (>10-fold, P < 0.03) in both malignant and goblet cell adenocarcinoids compared with normal and incidental lesions (P < 0.006). MAGE-D2 and MTA1 message were significantly elevated (>10-fold, P < 0.01) in the malignant and goblet cell adenocarcinoid tumors but not in the appendicitis-associated carcinoids or normal mucosa. The apoptotic marker, NALP1, was overexpressed (>50-fold, P < 0.05) in the appendicitis-associated and malignant appendiceal carcinoids but was significantly decreased (>10-fold, P < 0.05) in the goblet cell adenocarcinoids. Elevated CgA transcript and protein levels indicative of a carcinoid tumor were identified in one acute appendicitis sample with no histologic evidence of a tumor. CONCLUSIONS: These data demonstrate that malignant APCs and goblet cell adenocarcinoids have elevated expression of NAP1L1, MAGE-D2, and MTA1 compared with appendiceal carcinoids identified at surgery for appendicitis. This and the differences in NALP1 gene expression (decreased in goblet cell adenocarcinoids) provide a series of molecular signatures that differentiate carcinoids of the appendix. CgA identified all appendiceal tumors as well as covert lesions, which may be more prevalent than previously recognized. The molecular delineation of malignant appendiceal tumor potential provides a scientific basis to define the appropriate surgical management as opposed to morphologic assessment alone