Loss of Caveolin-1 Accelerates Neurodegeneration and Aging

The aged brain exhibits a loss in gray matter and a decrease in spines and synaptic densities that may represent a sequela for neurodegenerative diseases such as Alzheimer's. Membrane/lipid rafts (MLR), discrete regions of the plasmalemma enriched in cholesterol, glycosphingolipids, and sphingomyelin, are essential for the development and stabilization of synapses. Caveolin-1 (Cav-1), a cholesterol binding protein organizes synaptic signaling components within MLR. It is unknown whether loss of synapses is dependent on an age-related loss of Cav-1 expression and whether this has implications for neurodegenerative diseases such as Alzheimer's disease.We analyzed brains from young (Yg, 3-6 months), middle age (Md, 12 months), aged (Ag, >18 months), and young Cav-1 KO mice and show that localization of PSD-95, NR2A, NR2B, TrkBR, AMPAR, and Cav-1 to MLR is decreased in aged hippocampi. Young Cav-1 KO mice showed signs of premature neuronal aging and degeneration. Hippocampi synaptosomes from Cav-1 KO mice showed reduced PSD-95, NR2A, NR2B, and Cav-1, an inability to be protected against cerebral ischemia-reperfusion injury compared to young WT mice, increased Aβ, P-Tau, and astrogliosis, decreased cerebrovascular volume compared to young WT mice. As with aged hippocampi, Cav-1 KO brains showed significantly reduced synapses. Neuron-targeted re-expression of Cav-1 in Cav-1 KO neurons in vitro decreased Aβ expression.Therefore, Cav-1 represents a novel control point for healthy neuronal aging and loss of Cav-1 represents a non-mutational model for Alzheimer's disease

VLPs and particle strategies for cancer vaccines

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The TRPM2 channel nexus from oxidative damage to Alzheimer’s pathologies: An emerging novel intervention target for age-related dementia

Alzheimer’s disease (AD), an age-related neurodegenerative condition, is the most common cause of dementia among the elder people, but currently there is no treatment. A number of putative pathogenic events, particularly amyloid β peptide (Aβ) accumulation, are believed to be early triggers that initiate AD. However, thus far targeting Aβ generation/aggregation as the mainstay strategy of drug development has not led to effective AD-modifying therapeutics. Oxidative damage is a conspicuous feature of AD, but this remains poorly defined phenomenon and mechanistically ill understood. The TRPM2 channel has emerged as a potentially ubiquitous molecular mechanism mediating oxidative damage and thus plays a vital role in the pathogenesis and progression of diverse neurodegenerative diseases. This article will review the emerging evidence from recent studies and propose a novel ‘hypothesis’ that multiple TRPM2-mediated cellular and molecular mechanisms cascade Aβ and/or oxidative damage to AD pathologies. The ‘hypothesis’ based on these new findings discusses the prospect of considering the TRPM2 channel as a novel therapeutic target for intervening AD and age-related dementia

Cloning and expression in Escherichia coli of three fragments of diphtheria toxin truncated within fragment B.

We have constructed three different truncated versions of diphtheria toxin (a 535-amino-acid polypeptide) which correspond to the N-terminal 290, 377, and 485 amino acids of the toxin. These lengths include one, three, and all four of the putative membrane-spanning sequences of the toxin which are thought to play a role in the translocation of fragment A into cells. Each of these three genes has been modified at its 3' end to code for a C-terminal cysteine (to allow for disulfide linkage of a targeting ligand) or a gene fusion with alpha-melanocyte-stimulating hormone. We have also substituted the native diphtheria tox promoter (ptox) with the lambda pR promoter in an effort to overexpress these proteins. The truncated genes are expressed in Escherichia coli from both the tox promoter in a constitutive fashion and from the pR promoter by using the heat-inducible cI857 repressor. The clones produce proteins which react with anti-diphtheria toxin serum, which migrate at the anticipated Mr on Western blots, and which have ADP-ribosyltransferase activity. Constitutive synthesis from ptox leads to severe proteolytic degradation even in a protease-deficient strain. High-level expression from the pR promoter in the same lon htpR strain allows the full-length polypeptides to accumulate but also stops the growth of the cells. It appears that removal of as few as 50 amino acids from the C-terminus of diphtheria toxin alters its conformation, making it a target for proteases and causing overexpression lethality in the host cells

Cloning and structural analyses of hepatitis B virus DNAs, subtype adr.

Entire genomes of hepatitis B virus (subtype adr) have been cloned. The nucleotide sequence data were compared with other sequences of HBV genome including: adw [Valenzuela et al. (1981) in Animal Virus Genetics. Fields et al. eds. Academic Press, Inc., NY. pp. 57-70], ayw [Galibert et al. (1979) Nature, 281, 646-650], and adyw [Pasek et al. (1979) Nature 282, 575-579]. Four open coding frames for polypeptides larger than 6,000 dalton were found to be conserved and were highly compressed by overlapping with each other in one strand (L-strand). Sites of initiation of the S gene and termination of the P gene were not conserved. No conserved coding frame was found on the opposite strand (S strand). Amino acid sequences of six surface antigen (HBsAg) peptides, including subtypes adr, adw, and ayw, are deduced from the DNA sequences, and the substitution of amino acid residues which are consistent with the change of subtypes are demonstrated