Tau promotes neurodegeneration through global chromatin relaxation

The microtubule-associated protein tau is involved in a number of neurodegenerative disorders, including Alzheimer’s disease (AD). Previous studies link oxidative stress and subsequent DNA damage to neuronal death in AD and related tauopathies. Since DNA damage can significantly alter chromatin structure, we examined epigenetic changes in tau-induced neurodegeneration. We have found widespread loss of heterochromatin in tau transgenic Drosophila and mice, and in human AD. Importantly, genetic rescue of tau-induced heterochromatin loss substantially reduced neurodegeneration in Drosophila. We identified oxidative stress and subsequent DNA damage as a mechanistic link between transgenic tau expression and heterochromatin relaxation, and found that heterochromatin loss permits aberrant gene expression in tauopathies. Furthermore, large-scale analyses from human AD brains revealed a widespread transcriptional increase in genes that are heterochromatically silenced in controls. Our results establish heterochromatin loss as a toxic effector of tau-induced neurodegeneration, and identify chromatin structure as a potential therapeutic target in AD

Genomic Analysis of Immune Response against Vibrio Cholerae Hemolysin in Caenorhabditis elegans

Vibrio cholerae cytolysin (VCC) is among the accessory V. cholerae virulence factors that may contribute to disease pathogenesis in humans. VCC, encoded by hlyA gene, belongs to the most common class of bacterial toxins, known as poreforming toxins (PFTs). V. cholerae infects and kills Caenorhabditis elegans via cholerae toxin independent manner. VCC is required for the lethality, growth retardation and intestinal cell vacuolation during the infection. However, little is known about the host gene expression responses against VCC. To address this question we performed a microarray study in C. elegans exposed to V. cholerae strains with intact and deleted hlyA genes. Many of the VCC regulated genes identified, including C-type lectins, Prion-like (glutamine [Q]/asparagine [N]-rich)-domain containing genes, genes regulated by insulin/ IGF-1-mediated signaling (IIS) pathway, were previously reported as mediators of innate immune response against other bacteria in C. elegans. Protective function of the subset of the genes up-regulated by VCC was confirmed using RNAi. By means of a machine learning algorithm called FastMEDUSA, we identified several putative VCC induced immune regulatory transcriptional factors and transcription factor binding motifs. Our results suggest that VCC is a major virulence factor, which induces a wide variety of immune response- related genes during V. cholerae infection in C. elegans

Tau protein is cross-linked by transglutaminase in P301L tau transgenic mice

This is the publisher's version, also available electronically from "http://www.jneurosci.org".The microtubule-associated protein tau is highly soluble under physiological conditions. However, in tauopathies, tau protein aggregates into insoluble filaments and neurofibrillary tangles (NFTs). The mechanisms underlying the formation of tau filaments and NFTs in tauopathies remain unclear. Several lines of evidence suggest that transglutaminase may cross-link tau into stable, insoluble aggregates, leading to the formation of NFTs in Alzheimer's disease and progressive supranuclear palsy. To further determine the contribution of transglutaminase in the formation of NFTs, we compared the levels of cross-linked tau protein from P301L tau transgenic mice that develop NFTs to four-repeat wild-type (4RWT) tau transgenic and nontransgenic mice that do not develop NFT pathology. Immunoprecipitation and immunoblotting experiments show that transglutaminase cross-links phosphorylated tau in the hindbrain of P301L tau transgenic mice but not in mice overexpressing 4RWT tau and nontransgenic mice. Cross-linked, phosphorylated tau from P301L tau transgenic mice runs as high-molecular mass aggregates on Western blots, similar to cross-linked tau from paired helical filaments of Alzheimer's disease. We also used double-label immunofluorescence to demonstrate colocalization of PHF-1-immunoreactive tau and the transglutaminase-catalyzed cross-link in the hindbrain, spinal cord, and cortex of P301L tau transgenic mice. In the spinal cord, 87% of PHF-1-labeled cells colocalize with the transglutaminase-catalyzed cross-link. Additionally, transglutaminase enzymatic activity is significantly elevated in the spinal cord of P301L tau transgenic mice. These studies further implicate transglutaminase in the formation and/or stabilization of NFT and paired helical filaments and provide a model system to investigate the therapeutic potential of transglutaminase inhibitors in tauopathies

In vivo silencing of alpha-synuclein using naked siRNA

<p>Abstract</p> <p>Background</p> <p>Overexpression of α-synuclein (SNCA) in families with multiplication mutations causes parkinsonism and subsequent dementia, characterized by diffuse Lewy Body disease <it>post-mortem</it>. Genetic variability in <it>SNCA </it>contributes to risk of idiopathic Parkinson's disease (PD), possibly as a result of overexpression. <it>SNCA </it>downregulation is therefore a valid therapeutic target for PD.</p> <p>Results</p> <p>We have identified human and murine-specific siRNA molecules which reduce <it>SNCA in vitro</it>. As a proof of concept, we demonstrate that direct infusion of chemically modified (naked), murine-specific siRNA into the hippocampus significantly reduces <it>SNCA </it>levels. Reduction of <it>SNCA </it>in the hippocampus and cortex persists for a minimum of 1 week post-infusion with recovery nearing control levels by 3 weeks post-infusion.</p> <p>Conclusion</p> <p>We have developed naked gene-specific siRNAs that silence expression of <it>SNCA in vivo</it>. This approach may prove beneficial toward our understanding of the endogenous functional equilibrium of <it>SNCA</it>, its role in disease, and eventually as a therapeutic strategy for α-synucleinopathies resulting from <it>SNCA </it>overexpression.</p

Virtual teaching kitchen classes and cardiovascular disease prevention counselling among medical trainees

Background: Hands-on culinary medicine education for medical trainees has emerged as a promising tool for cardiovascular health promotion. Purpose: To determine whether virtual culinary medicine programming associates with Mediterranean diet (MedDiet) adherence and lifestyle medicine competencies among medical trainees across the USA. Method: A total of 1433 medical trainees across 19 sites over a 12-month period were included. The Cooking for Health Optimisation with Patients-Medical Trainees survey composed of 61 questions regarding demographics, nutritional attitudes, dietary habits including MedDiet score and lifestyle medicine counselling competencies. Multivariable logistic regression assessed the association of virtual culinary medicine education with MedDiet intake and nutritional attitudes. Results: There were 519 medical trainees who participated in virtual culinary medicine education and 914 medical trainees who participated in their standard nutrition curricula. More than one-half of participants were women (n=759) and the mean age was 27 years old. Compared with students enrolled in traditional nutrition curricula, participants in virtual culinary medicine education were 37% more likely to adhere to MedDiet guidelines for fruit intake (OR 1.37, 95% CI 1.03 to 1.83, p=0.03). Virtual culinary medicine education was associated with higher proficiency in lifestyle medicine counselling categories, notably recommendations involving fibre (OR 4.03; 95% CI 3.05 to 5.34), type 2 diabetes prevention (OR 4.69; 95% CI 3.51 to 6.27) and omega fatty acids (OR 5.21; 95% CI 3.87 to 7.02). Virtual culinary medicine education had a similar, although higher magnitude association with MedDiet counselling competency (OR 5.73, 95% CI 4.26 to 7.70) when compared with historical data previously reported using hands-on, in-person culinary medicine courseware (OR 4.97, 95% CI 3.89 to 6.36). Conclusions: Compared with traditional nutritional educational curricula, virtual culinary medicine education is associated with higher MedDiet adherence and lifestyle medicine counselling competencies among medical trainees. Both virtual and hands-on culinary medicine education may be useful for cardiovascular health promotion