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Purpose Bronchopulmonary dysplasia (BPD) is a respiratory complication characterized by abnormal alveolar development in premature infants. Geranylgeranylacetone (GGA) can induce heat shock protein (HSP) 70, which has cytoprotective effects against various stressors. Here, we investigated whether GGA protected neonatal lungs from hyperoxic stress in a murine BPD model, and measured the serum HSP70 levels in preterm humans treated with oxygen. Methods Newborn mice were exposed to >90% oxygen and administered GGA or vehicle alone orally on days 1, 2, and 3 of life. At 2 days of age, HSP70 expression in the lung was determined by western blotting. At 8 days of age, the lungs were processed for histological analysis. Radial alveolar count (RAC) and mean linear intercept (MLI) were measured as parameters of alveolarization. Apoptosis was evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method and cleaved caspase-3 immunohistochemistry. Serum HSP70 levels in preterm humans treated with oxygen were measured by enzyme-linked immunosorbent assay. Results GGA administration enhanced the HSP70 expression to two-fold compared with normoxia-exposed and vehicle-treated mice. Hyperoxia reduced HSP70 expression, whereas GGA abrogated the effects. Hyperoxia-exposed mice exhibited more apoptotic cells in lung parenchyma and a more simplified alveolar structure with less RAC and larger MLI than normoxia-exposed mice. GGA suppressed the increase in apoptotic cells and the structural changes of the lungs induced by hyperoxia. Serum HSP70 levels of preterm human infants gradually decreased with age. Conclusions GGA may attenuate hyperoxic injury in neonatal lungs and thereby may prevent the development of BPD., Author(s): Shuko Tokuriki [sup.1] , Aiko Igarashi [sup.1] , Takashi Okuno [sup.1] , Genrei Ohta [sup.1] , Hironobu Naiki [sup.2] , Yusei Ohshima [sup.1] Author Affiliations: (1) Department of Pediatrics, [...]

Because of the insolubility and polymeric properties of amyloid fibrils, techniques used conventionally to analyze protein structure and dynamics have often been hampered. Ultrasonication can induce the monomeric solution of amyloidogenic proteins to form amyloid fibrils. However, ultrasonication can break down preformed fibrils into shorter fibrils. Here, combining these 2 opposing effects on [[beta].sub.2]-microglobulin ([beta]2-m), a protein responsible for dialysis-related amyloidosis, we present that ultrasonication pulses are useful for preparing monodispersed amyloid fibrils of minimal size with an average molecular weight of [approximately equal to]1,660,000 (140-mer). The production of minimal and monodispersed fibrils is achieved by the free energy minimum under competition between fibril production and breakdown. The small homogeneous fibrils will be of use for characterizing the structure and dynamics of amyloid fibrils, advancing molecular understanding of amyloidosis. [[beta].sub.2]-microglobulin | dialysis-related amyloidosis | protein misfolding | analytical ultracentrifugation

A study was conducted to examine the spontaneous formation of amyloid [beta] fibrils on the quartz surface. The results provide insight into nucleation process, fibril morphology which affect the cytotoxicity of fibril and taxonomy of amyloid supramolecular assemblies.

[[beta].sub.2]-microglobulin, a protein responsible for dialysis-related amyloidosis, is used to achieve heat-triggered conversion of the salt-induced thin and flexible protofibrils into well-organized thick and straight mature amyloid fibrils. The results have highlighted the importance of the change in heat capacity in addressing the biological significance of interactions between solvent water and amyloid fibrils.

Various methodologies including spectrophotometry, spectrofluorometry and surface plasmon resonance (SPR) are used to study the formation of Alzheimer's [beta]-amyloid fibrils (fA[beta]) by various anti-amyloidogenic compounds. The in vitro experiments reveal that flavonoids inhibit a preferential and reversible binding to the amyloid fibril structure of fA[beta], which leads to the amyloidogenic effect against the fibrils.

Understanding the structure and formation of amyloid fibrils, the filamentous aggregates of proteins and peptides, is crucial in preventing diseases caused by their deposition and, moreover, for obtaining further insight into the mechanism of protein folding and misfolding. We have combined solid-state NMR, x-ray fiber diffraction, and atomic force microscopy to reveal the 3D structure of amyloid protofilament-like fibrils formed by a 22-residue K3 peptide ([Ser.sup.20]-[Lys.sup.41]) [[beta].sub.2]-microglobulin, a protein responsible for dialysis-related amyloidosis. Although a uniformly [sup.13]C, [sup.15]N-labeled sample was used for the NMR measurements, we could obtain the 3D structure of the fibrils on the basis of a large number of structural constraints. The conformation of K3 fibrils was found to be a [beta]-strand-loop-[beta]-strand with each K3 molecule stacked in a parallel and staggered manner. It is suggested that the fibrillar conformation is stabilized by intermolecular interactions, rather than by intramolecular hydrophobic packing as seen in globular proteins. Together with thermodynamic studies of the full-length protein, formation of the fibrils is likely to require side chains on the intermolecular surface to pack tightly against those of adjacent monomers. By revealing the structure of [[beta].sub.2]-microglobulin protofilament-like fibrils, this work represents technical progress in analyzing amyloid fibrils in general through solid-state NMR. 2,2,2-trifluoroethanol | amyloid fibril | dialysis-related amyloidosis | protein misfolding | x-ray fiber diffraction

A cosolvent system is reported that induces the fibrous aggregation of human tau four-repeat domain. The flexibility of the present system allows to inspect the actual role of anions in forming the fibrous aggregates.

Research has been conducted on the beta-amyloid fibrils. The kinetic model of fibrils' extension and dissociation has been investigated via the use of surface plasmon resonance biosensor and the results are reported.

Research has been conducted on the amyloid fibril formation of the mouse V (sub)L domain. The effect of the destabilized conformation on the amyloid fibril formation is discussed.

Research has been conducted on the beta2-microglobulin-related (A(beta)2M) amyloidosis. The results of the fluorescence spectroscopic analysis with thioflavin T and electron microscopic study demonstrate that A(beta)2M amyloid fibrils depolymerize into the monomeric beta2-m at a neutral to basic pH.

Results from in vitro experiments indicate that beta-amyloid fibril formation is dependent on the fresh peptide components added to the reaction than on the preexisting fibrils. A model for the interaction between the peptides is presented.

The mechanisms of apolipoprotein E- and antioxidant-mediated inhibition of beta-amyloid fibril (fAbeta) formation in vitro were compared based on a nucleation-dependent polymerization model that uses fluorescence spectroscopy with thioflavin T. In addition, the effect of apolipoprotein and antioxidant on the extension reaction of (fAbeta) was examined. Results showed that apolipoprotein E and antioxidant inhibit (fAbeta) formation in vitro by different mechanisms, indicating the existence of multiple pharmacological targets for the prevention of fAbeta formation.

Fluorescence spectroscopy was utilized to determine the effects of human apolipoprotein E (apoE) on the formation of the beta-amyloid fibril (beta-Af) in vitro. Administration of apoE in freshly prepared betaAfs induced inhibited fibril formation in a dose-dependent manner. The differential effects of ApoE on beta-Af formation were also characterized by the inhibition of the nucleation phase via a mechanism that was similar to the attenuation of the elongation phase by the cholesterol transport protein.

The SAMPI strain is a mouse model for accelerated senescence and severe senile amyloidosis. We studied the effects of the amyloidogenic apolipoprotein A-II gene (Apoa[2.sup.c]) on senile amyloidosis and the life span and progress of senescence of congenic mice (R1.P1-Apoa[2.sup.c]) which have Apoa[2.sup.c] of the SAMP1 strain on the genome of the normally aging SAMR1 strain. Age-associated and severe amyloid deposits were detected in R1.P1-Apoa[2.sup.c], as well as a 20% shorter life span than that of SAMRI. The scores of senescence increased more rapidly with age in R1.P1-Apoa[2.sup.c] than that of SAMR1, and the Gompertz function showed a bigger Y intercept but the same slope of regression line. These results suggest that severe senile amyloidosis induced by the Apoa[2.sup.c] gene shortens the life span of mice but does not accelerate the rate of senescence.

The studies related to the lysophosphatidic acid (LPA), an in vivo occurring lysophospholipid mediator which promoted amyloid formation under physiological conditions through a complex mechanism is presented. The results obtained and the observed increase in blood LPA levels in dialysis patients suggested that the interaction of LPA with [beta]2m might contribute to the pathomechanism of dialysis-related amyloidosis.

Amyloid nucleation through agitation is analyzed with [[beta].sub.2]-microglobulin, which is responsible for dialysis-related amyloidosis, in the presence of salt under acid and neutral pH conditions. The agitation-treated aggregates of both proteins have a high propensity to produce an amyloid nucleus even at natural pH, thus showing that the aggregation pathway has involved amyloid nucleation under entirely native conditions.

The effects of heat on the acid-unfolded monomer at pH 2.5 were studied to understand the initial stages in the formation of amyloid fibrils of [beta.sub.2]-microglobulin ([beta]2-m), a protein responsible for dialysis-related amyloidosis. It was found that moderate heat treatment of [beta]2-m in the presence of seed fibrils results in an exothermic sigmoidal transition leading to a conformational state and may be interpreted in terms of the effects of heat associated with the formation, the association and unfolding of fibrils.

A detailed analysis of peptide structures of fragments in fibril and the native system is carried out by employing vibrational spectroscopy. The infrared (IR) absorption for the fibril of the #21-31 fragment of beta(sub 2)-microglobulin shows that five of the residues in the #21-31 fibril are in a beta-sheet conformation, four are in a random conformation, and two are in a non-alpha/non-beta structure.

The role of electrostatic interactions and the effect of ionic cosolutes on amyloid formation are understood by investigating the effect of salts such as NaCl, NaI, NaClO4, and Na2SO4 on the amyloid fibril growth of beta2-microglobulin. The study conducted suggests that preferential interaction of sulfate ions with amyloidogenic proteins may have biological significance.

A study is carried out on beta2-microglobulin that is a major component of amyloid fibrils deposited in patients with dialysis-related amyloidosis. The results suggested that, the myofibrils derived from L-peptides and D-peptides form in a similar manner but with opposite stereochemistry, a cross-reaction between them is prevented because the geometry of the mixed sheet cannot satisfy dominant factors for beta-sheet stabilization.

The effects of sodium dodecyl sulfate (SDS) and other detergents on the conformation of beta2-m, the stability of Abeta2M amyloid fibrils, and the extension of amyloid fibrils at neutral pH, are investigated using fluorescence spectroscopy with thioflavin T (ThT), circular dichroism (CD) spectroscopy and electron microscopy. The findings display the sensitivity of Abeta2M fibril formation to solution conditions and suggest a possible role for lipid molecules in the development of Abeta2M amyloidosis.

The amyloid fibril has been recognized as another stable phase of peptide chains and an origin of dome kinds of diseases. A new approach based on IR linear dichroism analysis of amyloid fibrils using microscopy is reported.