Studies investigating the pathogenic role of the microtubule associated protein tau (MAPT) gene in Parkinson's disease (PD) have indicated that DNA methylation of the promoter region is aberrant in ...disease, leading to dysregulated MAPT expression. We examined two potential regulators of MAPT gene expression in respect to PD, a promoter-associated long non-coding RNA MAPT-AS1, and DNA methyltransferases (DNMTs), enzymes responsible for new and maintenance of DNA methylation. We assessed the relationship between expression levels of MAPT and the candidate MAPT-AS1, DNMT1, DNMT3A and DNMT3B transcripts in four brain regions with varying degrees of cell loss and pathology (putamen, anterior cingulate cortex, visual cortex and cerebellum) in N = 10 PD and N = 10 controls. We found a significant decrease in MAPT-AS1 expression in PD (p = 7.154 x 10-6). The transcript levels of both MAPT-AS1 (p = 2.569 x 10-4) and DNMT1 (p = 0.001) correlated with those of MAPT across the four brain regions, but not with each other. Overexpression of MAPT-AS1 decreased MAPT promoter activity by ∼2.2 to 4.3 fold in an in vitro luciferase assay performed in two cell lines (p ≤ 2.678 x 10-4). Knock-down expression of MAPT-AS1 led to a 1.3 to 6.3 fold increase in methylation of the endogenous MAPT promoter (p ≤ 0.011) and a 1.2 to 1.5 fold increased expression of the 4-repeat MAPT isoform transcript (p ≤ 0.013). In conclusion, MAPT-AS1 and DNMT1 have been identified as potential epigenetic regulators of MAPT expression in PD across four different brain regions. Our data also suggest that increased MAPT expression could be associated with disease state, but not with PD neuropathology severity.
Genetics of dementia Loy, Clement T, FRACP; Schofield, Peter R, Prof; Turner, Anne M, FRACP ...
The Lancet (British edition),
03/2014, Volume:
383, Issue:
9919
Journal Article
Peer reviewed
Summary 25% of all people aged 55 years and older have a family history of dementia. For most, the family history is due to genetically complex disease, where many genetic variations of small effect ...interact to increase risk of dementia. The lifetime risk of dementia for these families is about 20%, compared with 10% in the general population. A small proportion of families have an autosomal dominant family history of early-onset dementia, which is often due to mendelian disease, caused by a mutation in one of the dementia genes. Each family member has a 50% chance of inheriting the mutation, which confers a lifetime dementia risk of over 95%. In this Review, we focus on the evidence for, and the approach to, genetic testing in Alzheimer's disease ( APP , PSEN1 , and PSEN2 genes), frontotemporal dementia ( MAPT, GRN, C9ORF72 , and other genes), and other familial dementias. We conclude by discussing the practical aspects of genetic counselling.
Chondroitin sulfate is a glycosaminoglycan composed of N-acetylgalactosamine and glucuronic acid. It attaches to a core protein to form chondroitin sulfate proteoglycan (CSPG). Being a major ...component of the brain extracellular matrix, CSPGs are involved in neural development, axon pathfinding and guidance, plasticity and also regeneration after injury in the nervous system. In this review, we shall discuss the structure, the biosynthetic pathway, its functions in the nervous system and how we can improve regeneration in the nervous system by modulating its structure and binding properties.
Vaccines are commonly administered by injection using needles. Although transdermal microneedles are less invasive promising alternatives, needle‐free topical vaccination without involving physical ...damage to the natural skin barrier is still sought after as it can further reduce needle‐induced anxiety and is simple to administer. However, this long‐standing goal has been elusive since the intact skin is impermeable to most macromolecules. Here, we show an efficient, noninvasive transdermal vaccination by employing two key innovations: the use of hyaluronan (HA) as vaccine carriers and non‐ablative laser adjuvants. Conjugates of a model vaccine ovalbumin (OVA) and HA—HA–OVA conjugates—induced more effective maturation of dendritic cells in vitro, compared to OVA. Following topical administration in the skin, HA–OVA conjugates penetrated into the epidermis and dermis in murine and porcine skins, as revealed by intravital microscopy and fluorescence assay. Topical administration of HA‐OVA conjugates significantly elevated both humoral and mucosal antibodies, with peak levels at four weeks. An OVA challenge at week eight elicited strong immune‐recall responses. With pretreatment of the skin using non‐ablative fractional laser beams as adjuvant, strong immunization was achieved with much reduced doses of HA–OVA (1 mg kg–1 OVA). Our results demonstrate the potential of the noninvasive patch‐type transdermal vaccination platform.
A highly effective, noninvasive transdermal vaccination system is demonstrated using laser adjuvant and hyaluronan (HA) nanocarrier. Topically applied HA–OVA conjugates penetrate the intact skin efficiently and establish strong humoral (IgG) and mucosal (IgA) responses at ovalbumin (OVA) doses as small as 1 mg kg−1 in mice. The transdermal immunization efficiency is higher than intramuscular injection of OVA and similar to intramuscular injection of HA–OVA.
Summary
Perineuronal nets (PNNs) are meshed‐like extracellular matrix structures present on the surface of sub‐populations of neurons and are involved in regulating plasticity in the central nervous ...system (CNS). PNNs are formed at the end of the critical period during development and their formation closes the critical period for plasticity, as demonstrated in ocular dominance plasticity. One of the major components of PNNs are chondroitin sulphate proteoglycans (CSPGs), a family of inhibitory molecules for neuronal growth and regeneration. CSPGs are highly up‐regulated after injury in the CNS, including spinal cord and optic nerve. Enzymatic removal of CSPGs in the PNNs enhances plasticity, allows re‐organisation of circuitry and improves functional recovery. Recently, we also observed specific changes in chondroitin sulphate composition in ageing brains when compared to young adult brains. This change may underlie the loss of plasticity in ageing animals. We shall discuss the role of PNNs in regulating plasticity, regeneration and rehabilitation in the CNS, including the visual system in this talk.
In this study, we investigated the regulation of FOXM1 expression by estrogen receptor α (ERα) and its role in hormonal therapy and endocrine resistance. FOXM1 protein and mRNA expression was ...regulated by ER-ligands, including estrogen, tamoxifen (OHT) and fulvestrant (ICI182780; ICI) in breast carcinoma cell lines. Depletion of ERα by RNA interference (RNAi) in MCF-7 cells downregulated FOXM1 expression. Reporter gene assays showed that ERα activates FOXM1 transcription through an estrogen-response element (ERE) located within the proximal promoter region. The direct binding of ERα to the FOXM1 promoter was confirmed in vitro by mobility shift and DNA pull-down assays and in vivo by chromatin immunoprecipitation (ChIP) analysis. Our data also revealed that upon OHT treatment ERα recruits histone deacetylases to the ERE site of the FOXM1 promoter, which is associated with a decrease in histone acetylation and transcription activity. Importantly, silencing of FOXM1 by RNAi abolished estrogen-induced MCF-7 cell proliferation and overcame acquired tamoxifen resistance. Conversely, ectopic expression of FOXM1 abrogated the cell cycle arrest mediated by the anti-estrogen OHT. OHT repressed FOXM1 expression in endocrine sensitive but not resistant breast carcinoma cell lines. Furthermore, qRT-PCR analysis of breast cancer patient samples revealed that there was a strong and significant positive correlation between ERα and FOXM1 mRNA expression. Collectively, these results show FOXM1 to be a key mediator of the mitogenic functions of ERα and estrogen in breast cancer cells, and also suggest that the deregulation of FOXM1 may contribute to anti-estrogen insensitivity. Oncogene (2010) 29, 2983-2995; doi: 10.1038/onc.2010.47; published online 8 March 2010 Keywords: breast cancer; forkhead; estrogen receptor; FOXM1; endocrine resistance; transcription
Despite advances in high-dimensional cellular analysis, the molecular profiling of dynamic behaviors of cells in their native environment remains a major challenge. We present a method that allows us ...to couple the physiological behaviors of cells in an intact murine tissue to deep molecular profiling of individual cells. This method enabled us to establish a novel molecular signature for a striking migratory cellular behavior following injury in murine airways.
Photonic hydrogel sensors Yetisen, Ali K; Butt, Haider; Volpatti, Lisa R ...
Biotechnology advances,
2016 May-Jun, 2016-05-00, 20160501, Volume:
34, Issue:
3
Journal Article
Peer reviewed
Open access
Analyte-sensitive hydrogels that incorporate optical structures have emerged as sensing platforms for point-of-care diagnostics. The optical properties of the hydrogel sensors can be rationally ...designed and fabricated through self-assembly, microfabrication or laser writing. The advantages of photonic hydrogel sensors over conventional assay formats include label-free, quantitative, reusable, and continuous measurement capability that can be integrated with equipment-free text or image display. This Review explains the operation principles of photonic hydrogel sensors, presents syntheses of stimuli-responsive polymers, and provides an overview of qualitative and quantitative readout technologies. Applications in clinical samples are discussed, and potential future directions are identified.
The transacting activator of transduction (TAT) protein plays a key role in the progression of AIDS. Studies have shown that a +8 charged sequence of amino acids in the protein, called the TAT ...peptide, enables the TAT protein to penetrate cell membranes. To probe mechanisms of binding and translocation of the TAT peptide into the cell, investigators have used phospholipid liposomes as cell membrane mimics. We have used the method of surface potential sensitive second harmonic generation (SHG), which is a label-free and interface-selective method, to study the binding of TAT to anionic 1-palmitoyl-2-oleoyl- sn -glycero-3-phospho-1′- rac -glycerol (POPG) and neutral 1-palmitoyl-2-oleoyl- sn -glycero-3-phosphocholine (POPC) liposomes. It is the SHG sensitivity to the electrostatic field generated by a charged interface that enabled us to obtain the interfacial electrostatic potential. SHG together with the Poisson–Boltzmann equation yielded the dependence of the surface potential on the density of adsorbed TAT. We obtained the dissociation constants K d for TAT binding to POPC and POPG liposomes and the maximum number of TATs that can bind to a given liposome surface. For POPC K d was found to be 7.5 ± 2 μM, and for POPG K d was 29.0 ± 4.0 μM. As TAT was added to the liposome solution the POPC surface potential changed from 0 mV to +37 mV, and for POPG it changed from −57 mV to −37 mV. A numerical calculation of K d, which included all terms obtained from application of the Poisson–Boltzmann equation to the TAT liposome SHG data, was shown to be in good agreement with an approximated solution.
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