Abnormal intracellular Ca(2+) handling is an important factor in the progressive functional decline of dystrophic muscle. In the present study, we investigated the function of sarco(endo)plasmic reticulum (SR) Ca(2+) ATPase (SERCA) in various dystrophic muscles of mouse models of Duchenne muscular dystrophy. Our studies show that the protein expression of sarcolipin, a key regulator of the SERCA pump is abnormally high and correlates with decreased maximum velocity of SR Ca(2+) uptake in the soleus, diaphragm and quadriceps of mild (mdx) and severe (mdx:utr-/-) dystrophic mice. These changes are more pronounced in the muscles of mdx:utr-/- mice. We also found increased expression of SERCA2a and calsequestrin specifically in the dystrophic quadriceps. Immunostaining analysis further showed that SERCA2a expression is associated both with fibers expressing slow-type myosin and regenerating fibers expressing embryonic myosin. Together, our data suggest that sarcolipin upregulation is a common secondary alteration in all dystrophic muscles and contributes to the abnormal elevation of intracellular Ca(2+) concentration via SERCA inhibition.

Renin-angiotensin system inhibitors significantly reduce the incidence of arrhythmias. However, the underlying mechanism(s) is not well understood. We aim to test the hypothesis that Ang II induces early afterdepolarizations (EADs) and triggered activities (TAs) via the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-ROS-calmodulin kinase II (CaMKII) pathway. ROS production was analyzed in the isolated rabbit myocytes loaded with ROS dye. Ang II (1-2 µM) increased ROS fluorescence in myocytes, which was abolished by Ang II type 1 receptor blocker losartan, NADPH oxidase inhibitor apocynin, and antioxidant MnTMPyP, respectively. Action potentials were recorded using the perforated patch-clamp technique. EADs emerged in 27 out of 41 (66%) cells at 15.8 ± 1.6 min after Ang II (1~2 µM) perfusion. Ang II-induced EADs were eliminated by losartan, apocynin, or trolox. The CaMK II inhibitor KN-93 (n=6) and inhibitory peptide (AIP) (n=4) also suppressed Ang II-induced EADs, whereas the inactive analogue KN-92 did not. Nifedipine, a blocker of L-type Ca current (I Ca,L ), or ranolazine, an inhibitor of late Na current (I Na ), abolished Ang II-induced EADs. The effects of Ang II on major membrane currents were evaluated using voltage clamp. While Ang II at same concentrations had no significant effect on total outward K + current, it enhanced I Ca.L and late I Na , which were attenuated by losartan, apocynin, trolox, or KN-93. We conclude that Ang II induces EADs via intracellular ROS production through NADPH oxidase, activation of CaMKII, and enhancement of I Ca,L and late I Na . These results provide evidence supporting a link between renin-angiotensin system and cardiac arrhythmias.

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Human immunodeficiency virus-1 (HIV-1) Vpr encodes a 14 kDa protein that has been implicated in viral pathogenesis through in vitro modulation of several host cell functions. Vpr modulates cellular proliferation, cell differentiation, apoptosis and host cell transcription in a manner that involves the glucocorticoid pathway. To better understand the role of HIV-1 Vpr in host gene expression, approximately 9600 cellular RNA transcripts were assessed for their modulation in primary APC after treatment with a bioactive recombinant Vpr (rVpr) by DNA micro-array. As an extracellular delivered protein, Vpr down-modulated the expression of several immunologically important molecules including CD40, CD80, CD83 and CD86 costimulatory molecules on MDM (monocyte-derived macrophage) and MDDC (monocyte-derived dendritic cells). Maturation of dendritic cells (DC) is known to result in a decreased capacity to produce HIV due to a post-entry block of the HIV-1 replicative cycle. Based on the changes observed in the gene array, we analyzed maturation of DC generated from monocytes in tissue culture as influenced by Vpr. We observed that Vpr-treated immature MDM and MDDC were unable to acquire high levels of costimulatory molecules and failed to develop into mature DC, even in the presence of maturation signals. These studies have importance for understanding the interaction of HIV with the host immune system.

The present study was conducted to characterize 2 important native chicken breeds from India and compare them on growth, production, egg and semen quality, and welfare traits. The Aseel breed showed (P < 0.001) higher BW at different ages; higher shank, radius, and toe lengths at 40 wk of age; and greater egg weights at 28, 32, and 40 wk of age than did the Kadaknath breed. The Kadaknath breed reached sexual maturity at an early age, and it had higher 40-wk egg production (P < 0.001). Higher egg specific gravity (P < 0.05) and higher albumen (P < 0.001) and shell (P < 0.009) percentages in the Kadaknath were observed, whereas the Aseel breed had a higher yolk index (P < 0.004), higher yolk percentage (P < 0.001), and higher yolk-to-albumen ratio (P < 0.001). Concentration of sperm (P < 0.01), live sperm counts (P < 0.05), and semen appearance scores (P < 0.05) were higher in the Aseel breed than in the Kadaknath breed. The Aseel breed showed a greater incidence of feather-pecking behavior under floor rearing, and this was negligible or mild in the Kadaknath breed. Broodiness under cage rearing was observed (8.42%) in the Aseel breed. With regard to welfare traits, male Aseel birds had a significantly shorter (P < 0.05) duration of tonic immobility (TI) than did male Kadaknath birds. Furthermore, male Aseel birds had a shorter (P < 0.001) duration of TI than did female Aseel birds, whereas female Aseel birds had a longer (P < 0.05) duration of TI than did female and male Kadaknath birds. From this study, it was concluded that the breeds differed on various growth, production, egg and semen quality, and behavioral traits, but not on welfare traits, although female Aseel birds exhibited a greater fear response.