Cardiac protein expression patterns are associated with distinct inborn exercise capacity in non-selectively bred rats

In the present study, we successfully demonstrated for the first time the existence of cardiac proteomic differences between non-selectively bred rats with distinct intrinsic exercise capacities. A proteomic approach based on two-dimensional gel electrophoresis coupled to mass spectrometry was used to study the left ventricle (LV) tissue proteome of rats with distinct intrinsic exercise capacity. Low running performance (LRP) and high running performance (HRP) rats were categorized by a treadmill exercise test, according to distance run to exhaustion. The running capacity of HRPs was 3.5-fold greater than LRPs. Protein profiling revealed 29 differences between HRP and LRP rats (15 proteins were identified). We detected alterations in components involved in metabolism, antioxidant and stress response, microfibrillar and cytoskeletal proteins. Contractile proteins were upregulated in the LVs of HRP rats (α-myosin heavy chain-6, myosin light chain-1 and creatine kinase), whereas the LVs of LRP rats exhibited upregulation in proteins associated with stress response (aldehyde dehydrogenase 2, α-crystallin B chain and HSPβ-2). In addition, the cytoskeletal proteins desmin and α-actin were upregulated in LRPs. Taken together, our results suggest that the increased contractile protein levels in HRP rats partly accounted for their improved exercise capacity, and that proteins considered risk factors to the development of cardiovascular disease were expressed in higher amounts in LRP animals.

Filamina plaquetaria: una proteína del citoesqueleto integradora de la función celular / Platelet filamin: a cytoskeletal protein involved in cell signal integration and function

Activation of cellular receptors by diverse stimuli induces dramatic changes in shape and function to respond to the new circumstances of the cell. This modified behavior depends on the reorganization of the peripheral actin meshwork. An outstanding example of these processes can be found in platelets, from which much of the information available on cytoskeletal function has been obtained. Among the many actin-crosslinking proteins like spectrin, fimbrin or alpha actinin, filamin a (FLNa) emerges as the one with the highest potential in initiating the polimerization of actin filaments (F-actin) during the formation of tridimensional actin gels. FLNa also links actin filaments to the cytosolic domain of many membrane glycoproteins in platelets through its C-terminal region. In addition to participating in cell shape changes, FLNa is a scaffoldding protein that recruits numerous proteins involved in a completely different set of functions, including signal transduction, gene transcription regulation, and receptor translocation; however, the physiological role of FLNa in these processes has remained elusive. The purpose of the present communication is to briefly describe the characteristics of the macromolecules able to interact with FLNa and to discuss a possible role of FLNa during the transduction of signals from those molecular elements in platelets.

Organizaçäo do citoesqueleto e distribuiçäo da integrina 'ALFA' Ýb ß3 em plaquetas estimuladas por trombina: aplicaçöes no estudo de pacientes portadores de hipertensäo arterial pulmonar / Organization of cytoskeleton and distribution of integrin 'ALFA' Ýb ß3 in the study of pulmonary hypertensive patients

Os mecanismos envolvidos na ativaçäo e agregaçäo plaquetária em condiçöes fisiológicas e patológicas, têm sido amplamente investigados. O propósito deste estudo foi: 1. Estabelecer alguns métodos para análise da organizaçäo de elementos contráteis e distribuiçäo da integrina 'ALFA' Ýb ß3 em plaquetas normais estimuladas por trombina. Os experimentos foram realizados utilizando-se lisado total e preparaçöes de citoesqueleto e membrana plaquetária. Em todos os ensaios, a integrina foi identificada por "Western immunoblotting" com anticorpo anti-cadeia ß3; 2. O mesmo protocolo foi empregado para analisar os resultados em pacientes portadores de hipertensäo pulmonar, nas quais ativaçäo e agregaçäo de plaquetas ocorrem in vivo como já demonstrado; 3. Finalmente, os efeitos do ácido acetilsalicílico na organizaçäo do citoesqueleto e na retençäo da integrina 'ALFA' Ýb ß3 foram estudados em plaquetas normais utilizando-se a mesma metodologia...

Parietal cells contain most of the myosin, filamin and actin present in rat gastric glands

The association of myosin and a filamin-like protein to the F-actin cytoskeleton of parietal cells was studied in the rat gastric mucosa. Myosin and the filamin-like protein were localized by indirect immunofluorescence microscopy while the distribution of actin was established by using FITC-phalloidin. These cytoskeletal proteins, concentrated in the parietal cells, changed their distribution in correlation with the hydrochloric acid (HCl) secretory state of the cells and the appearance of a developed intracellular canaliculus. Thus,in resting parietal cells, actin showed a patchy distribution, delimiting the poorly developed secretory canaliculi, while myosin and the filamin-like protein distributed diffusely over the cytoplasm. In secreting cells, F-actin was concentrated in the cytoplasmic projections filling the canalicular lumen, while myosin and the filamin-like protein were excluded from this region, concentrating in the adjoining cytoplasm. The present results show that myosin and the filamin-like protein change their association with the secretory membranes in relation to the development of the secretory canaliculus of parietal cells. In resting cells, both proteins associate with the endocellular secretory membranes. In secreting cells, the microvillar projections of the canalicular surface formed by these membranes bind F-actin, but exclude myosin and the filamin-like protein

Fisiologia de la cicatrizacion cutanea / Physiology of the skin wound healing

Se presenta un resumen actualizado de todos los eventos fisiologicos responsables de la cicatrizacion de las heridas cutaneas. se describen las alteraciones reparativas asociadas a diferentes entidades clinicas como la desnutricion, las avitaminosis, la diabetes, el alcoholismo, etc.