Role of nuclear chromogranin B in inositol 1,4,5-trisphosphate-mediated nuclear Ca2+ mobilization

Recently, secretory granule Ca(2+) storage protein chromogranin B (CGB) was shown to be present in the nucleoplasm proper in a complex structure that consists of the inositol 1,4,5-trisphosphate receptor (IP(3)R)/Ca(2+) channels and the phospholipids. Further, the amounts of IP(3)Rs present in the nucleus of bovine chromaffin cells were shown to be comparable to that of the endoplasmic reticulum. Therefore, we investigated here the potential contribution of nuclear CGB on the IP(3)-dependent Ca(2+) mobilization in the nucleus, using both neuroendocrine PC12 and nonneuroendocrine NIH3T3 cells. Chromogranin A (CGA) expression in the NIH3T3 cells, which do not contain intrinsic chromogranins, increased the IP(3)-induced Ca(2+) releases in the nucleus by 45%, while CGB expression in the same cells increased the IP(3)-induced Ca(2+) releases in the nucleus by 80%. Microinjection of IP(3) into the nucleus of CGB-expressing NIH3T3 cells increased the IP(3)-dependent nuclear Ca(2+) mobilization approximately 3-fold, whereas in CGA-expressing cells it remained the same as that of control cells. In contrast, inhibition of CGA expression in PC12 cells by siRNA treatment decreased the IP(3)-induced Ca(2+) releases in the nucleus by 17%, while inhibition of CGB expression decreased the IP(3)-induced Ca(2+) releases in the nucleus by 55%. Microinjection of IP(3) into the nucleus of siCGB-treated PC12 cells decreased the IP(3)-dependent nuclear Ca(2+) mobilization by approximately 75%, whereas in siCGA-treated cells it remained the same as that of control cells. Given the presence of CGB in the nucleus, these results further highlight the critical contribution of nuclear CGB in the IP(3)-induced Ca(2+) release in the nucleus.     

Dominance of Lysobacter sp. in the rhizosphere of two coastal sand dune plant species, Calystegia soldanella and Elymus mollis

Bacterial diversity in the rhizosphere of beach morning glory (Calystegia soldanella) and wild rye (Elymus mollis), two of the major plant species inhabiting the coastal sane dune in Tae-An, Korea, was studied by the analysis of community 16S rRNA gene clones. The amplified rDNA restriction analysis (ARDRA) of the clones using HaeIII exhibited significant differences in the community composition between the two plant species as well as regional differences, but also identified a specific ARDRA pattern that was most common among the clones regardless of plant species. Subsequent sequence analysis indicated that the pattern was that of Lysobacter spp., which is a member of the family Xanthomonadaceae, class Gamma proteobacteria. The Lysobacter clones comprised 50.6% of the clones derived from C. soldanella and 62.5% of those from E. mollis. Other minor patterns included those of Pseudomonas spp., species of Rhizobium, Chryseobacterium spp. and Pantoea spp. among C. soldanella clones, and Pseudomonas sp. and Aeromonas hydrophila among E. mollis clones. It is not yet clear what kind of roles Lysobacter plays in association with sand dune plants, but its universal presence in the rhizosphere, together with the potential of this taxon for antagonistic activity against plant pathogens, suggests that Lysobacter might form a symbiotic relationship with its host plants.     

Senescence-associated beta-galactosidase is lysosomal beta-galactosidase

Replicative senescence limits the proliferation of somatic cells passaged in culture and may reflect cellular aging in vivo. The most widely used biomarker for senescent and aging cells is senescence-associated beta-galactosidase (SA-beta-gal), which is defined as beta-galactosidase activity detectable at pH 6.0 in senescent cells, but the origin of SA-beta-gal and its cellular roles in senescence are not known. We demonstrate here that SA-beta-gal activity is expressed from GLB1, the gene encoding lysosomal beta-D-galactosidase, the activity of which is typically measured at acidic pH 4.5. Fibroblasts from patients with autosomal recessive G(M1)-gangliosidosis, which have defective lysosomal beta-galactosidase, did not express SA-beta-gal at late passages even though they underwent replicative senescence. In addition, late passage normal fibroblasts expressing small-hairpin interfering RNA that depleted GLB1 mRNA underwent senescence but failed to express SA-beta-gal. GLB1 mRNA depletion also prevented expression of SA-beta-gal activity in HeLa cervical carcinoma cells induced to enter a senescent state by repression of their endogenous human papillomavirus E7 oncogene. SA-beta-gal induction during senescence was due at least in part to increased expression of the lysosomal beta-galactosidase protein. These results also indicate that SA-beta-gal is not required for senescence.     

Co-administration of live attenuated Salmonella enterica serovar Typhimurium expressing swine interleukin-18 and interferon-α provides enhanced Th1-biased protective immunity against inactivated vaccine of pseudorabies virus

The co-administration of two or more cytokines may generate additive or synergistic effects for controlling infectious diseases. However, the practical use of cytokine combinations for the modulation of immune responses against inactivated vaccine has not been demonstrated in livestock yet, primarily due to protein stability, production, and costs associated with mass administration. In light of the current situation, we evaluated the immunomodulatory functions of the combined administration of swine interleukin-18 (swIL-18) and interferon-α (swIFN-α) against an inactivated PrV vaccine using attenuated Salmonella enterica serovar Typhimurium as a cytokine delivery system. Co-administration of S. enterica serovar Typhimurium expressing swIL-18 and swIFN-α produced enhanced Th1-biased humoral and cellular immune responses against the inactivated PrV vaccine, when compared to single administration of S. enterica serovar Typhimurium expressing either swIL-18 or swIFN-α. Also, enhanced immune responses in co-administered piglets occurred rapidly after virulent PrV challenge, and piglets that received co-administration of S. enterica serovar Typhimurium expressing swIL-18 and swIFN-α displayed a greater alleviation of clinical severity following the virulent PrV challenge, as determined by clinical scores and cumulative daily weight gain. Furthermore, this enhancement was confirmed by reduced nasal shedding of PrV following viral challenge. Therefore, these results suggest that oral co-administration of S. enterica serovar Typhimurium expressing swIL-18 and swIFN-α provide enhanced Th1-biased immunity against inactivated PrV vaccine to alleviate clinical signs caused by PrV challenge.     

Hypothyroid States Mitigate the Diabetes-Induced Reduction of Calbindin D-28k, Calretinin, and Parvalbumin Immunoreactivity in Type 2 Diabetic Rats

In this study, we investigated the differences in calbindin D-28k (CB), calretinin, (CR) and parvalbumin (PV) immunoreactivity in the hippocampus of Zucker diabetic fatty (ZDF) rats and Zucker lean control (ZLC) rats. In addition, we observed the effects of hypothyroidism on the levels of immunoreactivity of these proteins in ZDF rats. For this study, 7-week-old ZDF rats were used, and methimazole treatment was continued for 5 weeks to induce hypothyroidism. The animals were sacrificed at 12 weeks of age. ZDF rats showed increased blood glucose levels compared to those in ZLC rats. Methimazole intervention significantly reduced total and free T3 levels, and it ameliorated the increase of blood glucose levels in ZDF rats. In ZLC rats, CB, CR, and PV immunoreactivity was detected in regions of the hippocampus proper. In vehicle-treated ZDF rats, CB, CR, and PV immunoreactivity was significantly decreased in the hippocampus. However, in the methimazole-treated rats, CB, CR, and PV immunoreactivity was significantly increased compared to that in the vehicle-treated rats. These results suggest that hypothyroidism ameliorated the diabetes-induced reduction of CB, CR, and PV immunoreactivity in the hippocampus.     

Replacement of microglial cells using Clodronate liposome and bone marrow transplantation in the central nervous system of SOD1(G93A) transgenic mice as an in vivo model of amyotrophic lateral sclerosis

Disease progression of amyotrophic lateral sclerosis (ALS) is partially mediated by the toxic microenvironment established by microglia. In the present study, we used SOD1G93A transgenic mice as an in vivo ALS model and replaced microglia expressing mutant SOD1 (mSOD1) with microglia expressing wild-type SOD1 (w/tSOD1) to modulate the toxic microenvironment. Stereotactic injection of Clodronate liposome, a selective toxin against the monocyte/macrophage system, into the fourth ventricle of the brains of 12-week-old asymptomatic ALS mice reduced the number of microglia effectively in the central nervous system. Subsequent bone marrow transplantation (BMT) with bone marrow cells (BMCs) expressing w/tSOD1 and GFP leads to replacement of the endogenous microglia of the ALS mice with microglia expressing w/tSOD1 and GFP. The expression of mSOD1 in the other neural cells was not influenced by the replacement procedures, and immunological side effects were not observed. The replacement of microglia significantly slowed disease progression and prolonged survival of the ALS mice compared with the ALS mice treated by stereotactic injection of PBS-liposome and BMT with BMCs expressing mSOD1 or w/tSOD1. These results suggest that replacement of microglia would improve the neural cell microenvironment, thereby slowing disease progression. The mechanisms and functional implications of this replacement require further elucidation.