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.

A focus on extracellular Ca²⁺ entry into skeletal muscle

The main task of skeletal muscle is contraction and relaxation for body movement and posture maintenance. During contraction and relaxation, Ca²⁺ in the cytosol has a critical role in activating and deactivating a series of contractile proteins. In skeletal muscle, the cytosolic Ca²⁺ level is mainly determined by Ca²⁺ movements between the cytosol and the sarcoplasmic reticulum. The importance of Ca²⁺ entry from extracellular spaces to the cytosol has gained significant attention over the past decade. Store-operated Ca²⁺ entry with a low amplitude and relatively slow kinetics is a main extracellular Ca²⁺ entryway into skeletal muscle. Herein, recent studies on extracellular Ca²⁺ entry into skeletal muscle are reviewed along with descriptions of the proteins that are related to extracellular Ca²⁺ entry and their influences on skeletal muscle function and disease.

High fat diet confers vascular hyper-contractility against angiotensin II through upregulation of MLCK and CPI-17

Obesity is a critical risk factor for the hypertension. Although angiotensin II (Ang II) in obese individuals is known to be upregulated in obesity-induced hypertension, direct evidence that explains the underlying mechanism for increased vascular tone and consequent increase in blood pressure (BP) is largely unknown. The purpose of this study is to investigate the novel mechanism underlying Ang II-induced hyper-contractility and hypertension in obese rats. Eight-week old male Sprague-Dawley rats were fed with 60% fat diet or normal diet for 4 months. Body weight, plasma lipid profile, plasma Ang II level, BP, Ang II-induced vascular contraction, and expression of regulatory proteins modulating vascular contraction with/without Ang II stimulation were measured. As a result, high fat diet (HFD) accelerated age-dependent body weight gaining along with increased plasma Ang II concentration. It also increased BP and Ang II-induced aortic contraction. Basal expression of p-CPI-17 and myosin light chain (MLC) kinase was increased by HFD along with increased phosphorylation of MLC. Ang II-induced phosphorylation of CPI-17 and MLC were also higher in HFD group than control group. In conclusion HFD-induced hypertension is through at least in part by increased vascular contractility via increased expression and activation of contractile proteins and subsequent MLC phosphorylation induced by increased Ang II.

Association Analysis Between FILIP1 Polymorphisms and Aspirin Hypersensitivity in Korean Asthmatics

PURPOSE: Aspirin exacerbated respiratory disease (AERD) results in a severe asthma attack after aspirin ingestion in asthmatics. The filamin A interacting protein 1 (FILIP1) may play a crucial role in AERD pathogenesis by mediating T cell activation and membrane rearrangement. We investigated the association of FILIP1 variations with AERD and the fall rate of forced expiratory volume in one second (FEV1). METHODS: A total of 34 common FILIP1 single nucleotide polymorphisms (SNPs) were genotyped in 592 Korean asthmatic subjects that included 163 AERD patients and 429 aspirin-tolerant asthma (ATA) controls. RESULTS: This study found that 5 SNPs (P=0.006-0.01) and 2 haplotypes (P=0.01-0.03) of FILIP1 showed nominal signals; however, corrections for the multiple testing revealed no significant associations with the development of AERD (P corr>0.05). In addition, association analysis of the genetic variants with the fall rate of FEV1, an important diagnostic marker of AERD, revealed no significant evidence (P corr>0.05). CONCLUSIONS: Although further replications and functional evaluations are needed, our preliminary findings suggest that genetic variants of FILIP1 might be not associated with the onset of AERD.

Response of masticatory muscles to passive stretch stimulus - from perspectives of functional appliances / 대한치과교정학회지

OBJECTIVE: The aims of this study were to examine whether a passive stretch stimulus by means of a functional appliance induces changes in the fiber composition of masticatory muscles and whether these changes are similar to the changes in stretched limb muscle fibers by using RT-PCR, western blot, and immunohistochemical assays. METHODS: Five male New Zealand White rabbits were fitted with a prefabricated inclined plane on the maxillary central incisors to force the mandible forward (- 2 mm) and downward (- 4 mm). Further, 1 hind limb was extended and constrained with a cast so that the extensor digitorum longus (EDL) was stretched when the animal used the limb. The animals were sacrificed after 1 week and the masseter, lateral pterygoid, and EDL were processed and compared with those from control animals (n = 3). RESULTS: The stretched EDL had a significantly higher percentage of slow fibers, whereas the stretched masticatory muscles did not show changes in the composition of the major contractile proteins after 7 days. CONCLUSIONS: The transition of fiber phenotypes in response to a stretch stimulus may take longer in the masticatory muscles than in the limb muscles.

Identification of cDNAs of Genes Suppressed during the Process of Atrophy in Rat Skeletal Muscle / 대한정형외과연구학회지

PURPOSE: To elucidate the molecular basis of muscle atrophy in cellular adaptation point of view, gene expression profiling in rat muscle atrophy model was performed. The functions changed by muscle atrophy were analyzed. MATERIAL AND METHODS: Sciatic nerve and femoral nerve were resected in right leg to make muscle atrophy model in rat. The left leg was considered as a compensatory hypertrophy model. The suppression subtractive hybridization (SSH) was done to identify the profile of differential gene expression during muscle atrophy followed by nerve injury in rat. The DNA fragments obtained in SSH were labeled with biotin and used as cDNA tags for isolation of full-length cDNA from cDNA library. Differentially expressed genes were confirmed by reverse dot blot hybridization. RESULTS: Down regulation of genes were much more predominant than up regulation. The profile of down regulated genes were composed of genes coding muscle contractile proteins, enzymes involving carbohydrate metabolism including glycolysis and glycogenolysis, enzymes in oxidative phoshorylation, and proteins related with calcium release. The target genes were isolated by enrichment using cDNA tags from cDNA library for further functional studies. We identified some novel genes related with muscle atrophy by nerve injury. CONCLUSION: During the process of muscle atrophy, genes coding muscle contractile proteins, enzymes in carbohydrate metabolism, enzymes in oxidative phosphorylation, and proteins related with calcium release were down regulated.

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.

Effect of season on Length-tension relation of gastrocnemius muscle of Uromastix Hardwickii

Seasonal variations in the biological activities of animals are commonly reported in literature. However, these variations are not studied yet in correlation with the structure and function of skeletal muscles in general and their mechanics in particular. This study was conducted on skeletal muscles of a reptile, Uromastix, to determine the effect of season on the shape of length-tension curves, active tension, passive tension and tension equilibrium length [TEL]. Result demonstrates that active tension obtained from gastrocnemius muscle was found to increase significantly from the winter [December] to peak summer month [June], which showed a significant fall till the second winter [December]. The passive tension was also found to increase significantly [P<0.0005] from winter [December] to peak summer [June] which also decreased significantly till the second winter [December]. Change in both the active and passive tensions has resulted in a rise in the average values of tension equilibrium length from the winter [December] to peak summer [June] and fall till second winter [December] .It is concluded that length-tension parameters exhibit variations between different seasons and reflect a dominancy of contractile elements towards summer and elastic elements towards winter in the gastrocnemius muscles of Uromastix

Effect of mono-valent anions on active, passive tensions and tension equilibrium length of gastrocnemii of Uromastix Hardwickii

The length tension relationship has been used to determine the contractile and elastic state of the muscle. However, the shape of the active and passive tensions has been found to vary from muscle to muscle and in different animals as well. It depends upon the muscle architecture and specific function it performs. The change in the state of a skeletal muscle produced under the influence of chemical agents is not evaluated for the parameters obtained from the length tension relation. In the present study an attempt has been made to observe the effects of mono-valent anion on the contractile characteristics of isolated Gastrocnemius muscles of Uromastix. The results demonstrated that both the active and passive tensions changed on treatment with mono-valent anions with a shift in their curves. This change was statistically significant for active tensions. Further, Tension equilibrium length [TEL] also affected significantly. It is concluded that length tension parameter, TEL < resting length [Lo] is also a useful indicator of muscle state representing dominant elasticity under the influence of mono-valent anions. It can be used to express the state of different contractile and elastic characters of the skeletal muscle

Search for interacting proteins of esophageal cancer related gene-1 encoded protein through the yeast two-hybrid system / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To understand the role that esophageal cancer related gene-1 (ECRG-1) plays and to search for ECRG-1-interacting proteins.</p><p><b>METHODS</b>A DNA fragment encoding the carboxy-terminus of ECRG-1 (amino acids 40 - 418) was inserted into pGBKT7-DNA-BD vector and fused in-frame to the DNA-binding domain of GAL4. Then, it was used as a bait to screen the human fetal liver cDNA library by yeast two-hybrid, with the cDNA fragment inserted into pACT2 vector and fused in-frame to the Gal4 activation domain. If ECRG-1 interacted with a protein encoded by a cDNA fragmant in the yeast, the transcription of reporter Gene could be activated. With the false positive clonies eliminated, the inserts in the positive plasmids were sequenced and compared to those in the GenBank.</p><p><b>RESULTS</b>In approximately 3 x 10(6) independent tansformants screened, 23 clonies exhibited the expression of reporter gene. After eliminating the false positive clonies, two cDNA fragments were obtained. DNA sequencing revealed that one encoded Miz-1 (Myc-interacting Zn finger protein-1), and another encoded FLNA (actin-binding protein-280), Miz-1, being a Zn finger protein, could be bound to p15 promotor and activated the transcription. FLNA, being an actin-binding protein took part in the TGF-beta pathway via interaction with Smad.</p><p><b>CONCLUSION</b>ECRG-1 is able to be specifically bound to Miz-1 and FLNA in the yeast. It may play a role in the regulation of cell cycle via interaction with Miz-1 and FLNA.</p>

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...

Role of nitric oxide in cardiac contractility

The aim of the present work was to investigate the direct role of NO, and the possibility that cGMP was its second messenger in cardiac contractility under basal cholinergic and adrenergic stimulated conditions. Experiments were performed on spontaneously beating atrial and electrically stimulated ventricular preparations isolated from rabbits. The results showed that inhibition of NO synthase by nitro-L-arginine had no significant effect on basal atrial or ventricular contractions and that the inotropic effect of acetyl choline or adrenaline did not differ significantly after inhibition of NO synthase. Also, it was observed that L-arginine and sodium nitroprusside decreased significantly ventricular contractions, but atrial contractions were not affected by L-arginine although increased significantly by high concentration of sodium nitroprusside. These effects of L-arginine or sodium nitroprusside were antagonized by the guanylate cyclase inhibitor methylene blue

A Study on Contractile Proteins of Muscles and Platelets in Idiopathic Scoliosis Patients / 대한정형외과학회잡지

There have been numerous hypotheses about the pathogenesis of idiopathic scoliosis, but it is still unclear. There are some reports that abnormalities of contractile proteins may play a role in the pathogenesis of idiopathic scoliosis. The purpose of this report is to study the quantitative abnormalities of contractile proteins in muscles and nonactivated and activated platelets, and to determine whether or not the abnormalities in contractile proteins may play a role in the pathogenesis of idiopathic scoliosis. The materials were 21 idiopathic scoliosis patients aged from 13 years to 28 years(average 19.2 years) and 20 persons aged from 17 years to 25 years(average 20.1 years) as a control group. The electrophoretic analysis(SDS-PAGE method) was done on platelets both unstimulated and stimulated with thrombin and also on proteins of paraspinal muscles and gluteus maximus of idiopathic scoliosis patient and paraspinal muscles of control group. The results are as follows. 1. The myosin/actin ratios of triton-insoluble fractions to paraspinal muscles in convex sides of main curvatures of scoliosis patients(1.69±0.81) were significantly decreased compared to those of concave sides(2.55±1.28), gluteus maximus muscles(2.56±1.70) and control group(2.61±1.01). 2. There were no significant differences between scoliosis group and control group in the actin/myosin ratios of triton-insoluble fractions of the platelets both nonactivated and activated by thrombin. In conclusion, abnormalities of contractile protein in paraspinal muscles of convex side may play a role in the pathogenesis of idiopathic scoliosis, rather than abnormalities of systemic contractile protein.

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

A Study on the Cardiac Myofibrillar ATPase Activity in Diabetic Rats

Diabetes mellitus is known to be associated with a specific cardiomyopathy. This is evident from the clinical-pathological work and the epidemiologic data. An investigation was made in this study to determine whether diabetic cardiomyopathy in rats is associated with an alteration of biochemical characteristics of cardiac contractile proteins. Rats were made diabetic with intravenous injection of streptozotocin and hearts removed 8 weeks later for the isolation of myofibrils. The basal ATPase activity of myofibrils from diabetic hearts was significantly lower than that of the controls, suggesting the presence of some subtle structural and conformational changes in diabetic myofibrils. The activating effect of Mg ions on the myofibrillar actomyosin system of rat heart muscle was also demonstrated. Sodium dodecylsulfate gel electrophoresis showed the presence of myosin heavy chain, light chain 1 and 2, actin and troponin but failed to reveal differences in the patterns of these contractile proteins of light subunits between diabetics and controls. The deficiency in utilization of energy rich phosphates by the myofibrillar protein may be one of of the main mechanisms of cardiodepression observed in diabetic hearts. The cardiac myofibrillar ATPase activity may be one of useful measurements in evaluating pathophysiological states of cardiac contractile proteins.

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.