Overexpression of FK506-Binding protein FKBP12.6 in cardiomyocytes reduces ryanodine receptor-mediated Ca2+ leak from the sarcoplasmic reticulum and increases contractility

The FK506-binding protein FKBP12.6 is tightly associated with the cardiac sarcoplasmic reticulum (SR) Ca2+-release channel (ryanodine receptor type 2 [RyR2]), but the physiological function of FKBP12.6 is unclear. We used adenovirus (Ad)-mediated gene transfer to overexpress FKBP12.6 in adult rabbit cardiomyocytes. Western immunoblot and reverse transcriptase-polymerase chain reaction analysis revealed specific overexpression of FKBP12.6, with unchanged expression of endogenous FKBP12. FKBP12.6-transfected myocytes displayed a significantly higher (21%) fractional shortening (FS) at 48 hours after transfection compared with Ad-GFP-infected control cells (4.8+/-0.2% FS versus 4+/-0.2% FS, respectively; n=79 each; P=0.001). SR-Ca2+ uptake rates were monitored in beta -escin-permeabilized myocytes using Fura-2. Ad-FKBP12.6-infected cells showed a statistically significant higher rate of Ca2+ uptake of 0.8+/-0.09 nmol/s(-1)/10(6) cells (n = 8, P<0.05) compared with 0.52+/-0.1 nmol/s(-1)/10(6) cells in sham-infected cells (n = 8) at a [Ca2+] of 1 <mu>mol/L. In the presence of 5 mu mol/L ruthenium red to block Ca2+ efflux via RyR2, SR-Ca2+ uptake rates were not significantly different between groups. From these measurements, we calculate that SR-Ca2+ leak through RyR2 is reduced by 53% in FKBP12.6-overexpressing cells. Caffeine-induced contractures were significantly larger in Ad-FKBP12.6-infected myocytes compared with Ad-GFP-infected control cells, indicating a higher SR-Ca2+ load. Taken together, these data suggest that FKBP12.6 stabilizes the closed conformation state of RyR2. This may reduce diastolic SR-Ca2+ leak and consequently increase SR-Ca2+ release and myocyte shortening

Ergotropic effect in cardiac tissue after electromagnetic and β-adrenergic stimulus

In a murine ventricular cardiac tissue in vitro, via an image processing analysis, we have studied the ergotropic effect (contraction energy) after electromagnetic stimulation (frequency, 75 Hz), isoproterenol administration (10 μM), and their combination. We have found that the electromagnetic stimulation is able to counteract the β-adrenergic action of isoproterenol

Fatigue, emotional exhaustion and perceived health complaints associated with work-related characteristics in employees with and without chronic diseases.

Contains fulltext : 52162.pdf (publisher's version ) (Closed access)OBJECTIVES: Ageing of the Dutch working force and increasingly more stringent restrictions regarding early retirement and disability benefits are leading to higher numbers of workers with ill health. Until now, only a few studies have explored how employees with ill health perceive their work. This study investigated possible differences in scores on fatigue, emotional exhaustion, perceived health complaints and various work-related characteristics between chronically ill (CIWs) and non-chronically ill workers (NCIWs), as well as differences in associations between work- and health-related characteristics. METHODS: A questionnaire was sent to all employees of a Dutch university to collect data on perceived work-related and health-related characteristics (response 49.1%). Differences in various scores were analysed using chi (2)-tests and the general linear model. Associations between the work- and the health-related characteristics were determined by multiple linear regression analyses in the CIWs (n = 444) and NCIWs (n = 1,347) separately. Interaction terms were included to detect differences between the two groups. RESULTS: The results indicated that the CIWs had less favourable scores on the three health-related characteristics. Also, the CIWs scored less favourably than the NCIWs on almost all the work-related characteristics. In the two groups, negative work-related aspects, such as higher work pressure, contributed most to explaining the variance in the health-related characteristics. However, in the CIWs, fatigue was not explained by the work-related aspects as much as in the NCIWs. In the CIWs, the association between unpleasant treatment and the health-related characteristics was stronger than in the NCIWs, but there were indications that autonomy, possibilities for learning and social support from superiors also played an important role. CONCLUSIONS: CIWs perceived more fatigue, emotional exhaustion and health complaints than NCIWs. There were different patterns of associations between work- and health-related characteristics in the NCIWs and CIWs. Future studies on associations between work-related characteristics and health should take the presence of chronic disease into account

Peptide-Based Inhibition of NF-κB Rescues Diaphragm Muscle Contractile Dysfunction in a Murine Model of Duchenne Muscular Dystrophy

Deterioration of diaphragm function is one of the prominent factors that contributes to the susceptibility of serious respiratory infections and development of respiratory failure in patients with Duchenne Muscular Dystrophy (DMD). The NF-κB signaling pathway has been implicated as a contributing factor of dystrophic pathology, making it a potential therapeutic target. Previously, we demonstrated that pharmacological inhibition of NF-κB via a small NEMO Binding Domain (NBD) peptide was beneficial for reducing pathological features of mdx mice. Now, we stringently test the effectiveness and clinical potential of NBD by treating mdx mice with various formulations of NBD and use diaphragm function as our primary outcome criteria. We found that administering DMSO-soluble NBD rescued 78% of the contractile deficit between mdx and wild-type (WT) diaphragm. Interestingly, synthesis of a GLP NBD peptide as an acetate salt permitted its solubility in water, but as a negative consequence, also greatly attenuated functional efficacy. However, replacing the acetic acid counterion of the NBD peptide with trifluoroacetic acid retained the peptide’s water solubility and significantly restored mdx diaphragm contractile function and improved histopathological indices of disease in both diaphragm and limb muscle. Together, these results support the feasibility of using a mass-produced, water-soluble NBD peptide for clinical use