Regulation of skeletal muscle development and homeostasis by gene imprinting, histone acetylation and microRNA

Epigenetics is defined as heritable information other that the DNA sequence itself. The concept implies that the regulation of gene expression is highly complex and epigenetics can control from fine tuning to permanent gene activation/deactivation. Skeletal muscle is the main tissue for locomotion and energy metabolism in the body, and represent at least 40% of the body mass. Body mass and function vary according to age but also quickly adapt to physiological as well as pathological cues. Besides transcriptional mechanisms that control muscle differentiation, postnatal growth and remodeling, there are numerous epigenetic mechanisms of regulation that modulate muscle gene expression. In this review, we describe and discuss only some of the mechanisms of epigenetic regulation - such as DNA methylation, histone modifications, and microRNAs - that have been characterized in detail and that we believe are crucial for skeletal muscle development and disease

Proposal for Introducing a Digital Aesthetic Dentistry Course in Undergraduate Program: Contents and Ways of Administration

Background: Nowadays, digital dentistry is a fundamental skill that dentists need to acquire at this time. The digital workflow has gained acceptance and is widely used in most disciplines of dentistry. For this reason, it might be advisable to include this content in the undergraduate curriculum. The aim of this work was to create a course in digital aesthetic dentistry and evaluate its effectiveness. Methods: Dental students at the University of Verona (from third to sixth year) participated in a 2-h course on photography, digital aesthetic analysis, and digitally planned rehabilitations. Students were randomly divided into two groups, the first group attending the course with video tutorials and the second group attending the traditional class with slides. The students’ ability to perform digital aesthetic analysis and rehabilitation was tested. In addition, a questionnaire was completed to determine student satisfaction with the course and method of delivery. Statistical analysis was performed. Results: The course was highly appreciated, especially by the students who received the video tutorials. Good results were obtained in the performance of digital analysis and rehabilitation, which were better in the first group. Conclusions: Digital aesthetic dentistry was a success in terms of newly acquired skills. From this point of view, the proposal of a course on this subject in the undergraduate curriculum deserves a close evaluation. The video tutorial method seems to be a good way to teach operative digital procedure

Self-assembled extracellular matrix protein networks by microcontact printing.

Physiological patterns of the extracellular matrix protein, laminin-1, were obtained on glass substrates by physisorption-assisted microcontact printing. Besides the well-retained antigenicity confirmed by indirect immunofluorescence assays, we investigated the supramolecular organization of the proteins by atomic force microscopy. We found the characteristic protein self-assembling in polygonal networks with well-defined sub-100 nm quaternary structures of laminin. The formation of these physiological mesh-like protein matrices was obtained by means of one-step soft lithography without any preliminary functionalization of glass, which can be exploited for many possible applications for cell cultures and biomolecular devices

Gli3 is required in Emx1+ progenitors for the development of the corpus callosum

AbstractThe corpus callosum (CC) is the largest commissure in the forebrain and mediates the transfer of sensory, motor and cognitive information between the cerebral hemispheres. During CC development, a number of strategically located glial and neuronal guidepost structures serve to guide callosal axons across the midline at the corticoseptal boundary (CSB). Correct positioning of these guideposts requires the Gli3 gene, mutations of which result in callosal defects in humans and mice. However, as Gli3 is widely expressed during critical stages of forebrain development, the precise temporal and spatial requirements for Gli3 function in callosal development remain unclear. Here, we used a conditional mouse mutant approach to inactivate Gli3 in specific regions of the developing telencephalon in order to delineate the domain(s) in which Gli3 is required for normal development of the corpus callosum. Inactivation of Gli3 in the septum or in the medial ganglionic eminence had no effect on CC formation, however Gli3 inactivation in the developing cerebral cortex led to the formation of a severely hypoplastic CC at E18.5 due to a severe disorganization of midline guideposts. Glial wedge cells translocate prematurely and Slit1/2 are ectopically expressed in the septum. These changes coincide with altered Fgf and Wnt/β-catenin signalling during CSB formation. Collectively, these data demonstrate a crucial role for Gli3 in cortical progenitors to control CC formation and indicate how defects in CSB formation affect the positioning of callosal guidepost cells

Histone deacetylase 4 is crucial for proper skeletal muscle development and disease

Epigenetics plays a pivotal role in modulating gene response to physiological or pathological stimuli. Histone Deacetylase inhibitors (HDACi) have been used in the treatment of various cancers1, are ef-fective in several animal models of neurodegenerative diseases, including amyotrophic lateral scle-rosis (ALS), and are currently in clinical trial to promote muscle repair in muscular dystrophies2. However, long-term use of pan-HDAC inhibitors is not tolerated3. The assignment of distinct biologi-cal functions to individual HDACs in skeletal muscle is a prerequisite to improve the efficacy of pharmacological treatments based on HDACi. HDAC4 is a member of class II HDACs that mediates many cellular responses. Clinical reports suggest that inhibition of HDAC4 can be beneficial to cancer cachexia, dystrophic or ALS patients. All the above conditions are characterized by progressive mus-cle wasting and up-regulation of HDAC4 expression in skeletal muscle, suggesting a potential role for this protein in regulating these diseases. To study the role of HDAC4 with a genetic approach, we generated several models of muscle disease in mice lacking HDAC4 in skeletal muscle: cancer ca-chexia, by implanting Lewis lung carcinoma (LLC), muscular dystrophy, by using mdx mice, or ALS, by using SODG93A mice. Lack of HDAC4 worsens skeletal muscle atrophy induced by both LLC and ALS, demonstrated by a reduction in muscle mass and myofibers size. Conversely, dystrophic mice lacking HDAC4 in skeletal muscle show an increased number of necrotic myofibers and run less efficiently than mdx mice. The aggravation of the dystrophic phenotype may be partially due to the impairment in skeletal muscle regeneration observed in mice lacking HDAC4 in skeletal muscle. Our results indi-cate that HDAC4 is necessary for maintaining skeletal muscle homeostasis and function. Current studies aim to investigate the molecular mechanisms underlying the role of HDAC4 in skeletal mus-cle maintenance in response to cancer cachexia, ALS or muscular dystrophy

A cost-minimization analysis of a preventive testing strategy for relatives of patients with BRCA mutated ovarian cancer

Purpose: This study aims to estimate the cost-minimization strategy of a preventive testing strategy destined to relatives of patients with BRCA mutated cancer versus a no test strategy in Italia. Methods: A BRCA testing pathway was designed by a panel of experts based on the MSTM Excel (2010) tool; the analysis was carried out considering the perspective of the Italian National Health Service. Two alternatives were considered: 1) preventive BRCA testing for relatives of patients affected by ovarian cancer carrying a BRCA1/BRCA2 mutation; 2) no test. Cost and effectiveness data, derived from literature and published sources validated by a Board of experts, were discounted using a discount factor equal to 3%. Probabilistic sensitivity analysis was performed. Results: Considering an average cost of therapy for breast and ovarian cancer major of €90,000.00 per case, the economic impact related to the preventive testing strategy are equal to –€17,814,767.25. The sensitivity analysis confirms these results in the totality of the simulations performed. Conclusions: Preventive genetic testing in relatives of patients affected by ovarian cancer is cost-effective and represents a sustainable cost for the National Healthcare System in Italia, also in the light of its reference values

Verocytotoxin-Producing Escherichia coli O26 in raw water buffalo (Bubalus bubalis) milk products in Italy

Escherichia coli 026 is known as a verocytotoxin-producing E. coli (VTEC) organism that causes severe foodborne diseases such as hemorrhagic colitis and hemolytic uremic syndrome. Although cattle are the most important reservoir of VTEC, only a few reports on the role of water buffalo (Bubalus bubalis) as a reservoir of VTEC and on the presence of these organisms in their milk are available. However, in Southern Italy, where water buffalo are intensively reared, an outbreak of hemolytic uremic syndrome due to E. coli 026 has recently been reported, in which the consumption of typical dairy products was considered to be a common risk factor. The aims of this work were to assess the prevalence of E. coli 026 in raw water buffalo milk, to characterize the virulence gene profiles of the isolates, and to evaluate their phenotypic antimicrobial resistance pattern. Of 160 analyzed samples, 1 (0.6%) tested positive for E. coli 026, and the isolate showed the stx1+ lstx2+leae-lhlyA+ genotypic profile. The strain showed resistance against glycopeptides, macrolides, and penicillins. The presence of VTEC organisms in raw water buffalo milk could be considered to be a potential threat to consumers; however, the strict adherence to the processes used in the preparation of the most common buffalo dairy products could strongly mitigate the foodborne risk. To our knowledge, this article reports the first isolation and characterization of E. coli 026 VTEC in raw water buffalo milk. Copyright ©, International Association for Food Protectio

Analysis of the LKB1-STRAD-MO25 complex

Mutations in the LKB1 tumour suppressor threonine kinase cause the inherited Peutz-Jeghers cancer syndrome and are also observed in some sporadic cancers. Recent work indicates that LKB1 exerts effects on metabolism, polarity and proliferation by phosphorylating and activating protein kinases belonging to the AMPK subfamily. In vivo, LKB1 forms a complex with STRAD, an inactive pseudokinase, and MO25, an armadillo repeat scaffolding-like protein. Binding of LKB1 to STRAD-MO25 activates LKB1 and re-localises it from the nucleus to the cytoplasm. To learn more about the inherent properties of the LKB1-STRAD-MO25 complex, we first investigated the activity of 34 point mutants of LKB1 found in human cancers and their ability to interact with STRAD and MO25. Interestingly, 12 of these mutants failed to interact with STRAD-MO25. Performing mutagenesis analysis, we defined two binding sites located on opposite surfaces of MO25α, which are required for the assembly of MO25α into a complex with STRADα and LKB1. In addition, we demonstrate that LKB1 does not require phosphorylation of its own T-loop to be activated by STRADα-MO25α, and discuss the possibility that this unusual mechanism of regulation arises from LKB1 functioning as an upstream kinase. Finally, we establish that STRADα, despite being catalytically inactive, is still capable of binding ATP with high affinity, but that this is not required for activation of LKB1. Taken together, our findings reinforce the functional importance of the binding of LKB1 to STRAD, and provide a greater understanding of the mechanism by which LKB1 is regulated and activated through its interaction with STRAD and MO25