Heat shock factor 1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of bone marrow stem/progenitor cells

Bone marrow (BM)-derived stem/progenitor cells play an important role in ischemia-induced angiogenesis in cardiovascular diseases. Heat shock factor 1 (HSF1) is known to be induced in response to hypoxia and ischemia. We examined whether HSF1 contributes to ischemia-induced angiogenesis through the mobilization and recruitment of BM-derived stem/progenitor cells using HSF1-knockout (KO) mice. After the induction of ischemia, blood flow and microvessel density in the ischemic hindlimb were significantly lower in the HSF1-KO mice than in the wild-type (WT) mice. The mobilization of BM-derived Sca-1- and c-kit-positive cells in peripheral blood after ischemia was significantly lower in the HSF1-KO mice than in the WT mice. BM stem/progenitor cells from HSF1-KO mice showed a significant decrease in their recruitment to ischemic tissue and in migration, adhesion, and survival when compared with WT mice. Blood flow recovery in the ischemic hindlimb significantly decreased in WT mice receiving BM reconstitution with donor cells from HSF1-KO mice. Conversely, blood flow recovery in the ischemic hindlimb significantly increased in HSF1-KO mice receiving BM reconstitution with donor cells from WT mice. These findings suggest that HSF1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of BM-derived stem/progenitor cells.     

Activation of BMP-Smad1/5/8 signaling promotes survival of retinal ganglion cells after damage in vivo

While the essential role of bone morphogenetic protein (BMP) signaling in nervous system development is well established, its function in the adult CNS is poorly understood. We investigated the role of BMP signaling in the adult mouse retina following damage in vivo. Intravitreal injection of N-methyl-D-aspartic acid (NMDA) induced extensive retinal ganglion cell death by 2 days. During this period, BMP2, -4 and -7 were upregulated, leading to phosphorylation of the downstream effector, Smad1/5/8 in the inner retina, including in retinal ganglion cells. Expression of Inhibitor of differentiation 1 (Id1; a known BMP-Smad1/5/8 target) was also upregulated in the retina. This activation of BMP-Smad1/5/8 signaling was also observed following light damage, suggesting that it is a general response to retinal injuries. Co-injection of BMP inhibitors with NMDA effectively blocked the damage-induced BMP-Smad1/5/8 activation and led to further cell death of retinal ganglion cells, when compared with NMDA injection alone. Moreover, treatment of the retina with exogenous BMP4 along with NMDA damage led to a significant rescue of retinal ganglion cells. These data demonstrate that BMP-Smad1/5/8 signaling is neuroprotective for retinal ganglion cells after damage, and suggest that stimulation of this pathway can serve as a potential target for neuroprotective therapies in retinal ganglion cell diseases, such as glaucoma.     

Claudin-4 Deficiency Results in Urothelial Hyperplasia and Lethal Hydronephrosis

Claudin (Cld)-4 is one of the dominant Clds expressed in the kidney and urinary tract, including selective segments of renal nephrons and the entire urothelium from the pelvis to the bladder. We generated Cldn4 ^−/− mice and found that these mice had increased mortality due to hydronephrosis of relatively late onset. While the renal nephrons of Cldn4 ^−/− mice showed a concomitant diminution of Cld8 expression at tight junction (TJ), accumulation of Cld3 at TJ was markedly enhanced in compensation and the overall TJ structure was unaffected. Nonetheless, Cldn4 ^−/− mice showed slightly yet significantly increased fractional excretion of Ca²⁺ and Cl⁻, suggesting a role of Cld4 in the specific reabsorption of these ions via a paracellular route. Although the urine volume tended to be increased concordantly, Cldn4 ^−/− mice were capable of concentrating urine normally on dehydration, with no evidence of diabetes insipidus. In the urothelium, the formation of TJs and uroplaques as well as the gross barrier function were also unaffected. However, intravenous pyelography analysis indicated retarded urine flow prior to hydronephrosis. Histological examination revealed diffuse hyperplasia and a thickening of pelvic and ureteral urothelial layers with markedly increased BrdU uptake in vivo. These results suggest that progressive hydronephrosis in Cldn4 ^−/− mice arises from urinary tract obstruction due to urothelial hyperplasia, and that Cld4 plays an important role in maintaining the homeostatic integrity of normal urothelium.     

Identification of IL-18 and Th17 cells in salivary glands of patients with Sjögren's syndrome, and amplification of IL-17-mediated secretion of inflammatory cytokines from salivary gland cells by IL-18

IL-18 is a proinflammatory cytokine and plays an important pathogenic role in inflammatory and autoimmune disorders. IL-17 is also a proinflammatory cytokine and IL-17-secreting Th17 cells are involved in autoimmunity. However, the pathological roles of IL-18 and Th17 cells in Sj?gren's syndrome (SS) remain to be elucidated. This study showed that the expression of IL-18 was detected in acinar cells, intraducts, and CD68(+) macrophages in salivary glands of SS patients, but not in those of healthy subjects or patients with chronic graft-vs-host disease, by immunohistochemistry, and immunoblot analysis revealed that 24-kDa precursor form of IL-18 (proIL-18) and 18-kDa mature IL-18 were detected in SS salivary glands. The majority of the infiltrating cells in the salivary glands of SS patients were CD4(+) T cells, and CD8(+) T cells were infiltrated to a lesser extent. The predominant expression of IL-17 was found in infiltrating CD4(+) T cells, whereas a small number of infiltrating CD8(+) T cells expressed IL-17. Human salivary gland HSY and acinar AZA3 cells constitutively expressed proIL-18 and caspase-1, and a calcium ionophore A23187 induced the secretion of IL-18 from the cells. HSY and AZA3 cells expressed IL-18R and IL-17R on the cell surface, and IL-18 amplified the secretion of IL-6 and IL-8 that were induced by low amounts of IL-17. Primary salivary gland cells from normal subjects partially confirmed these findings. These results suggest that IL-18 and Th17 cells detected in the salivary glands in SS patients are associated with the pathogenesis of SS in the salivary glands.     

Helminths collected from imported pet murids, with special reference to concomitant infection of the golden hamsters with three pinworm species of the genus Syphacia (Nematoda: oxyuridae)

A total of 210 individuals of 13 species belonging to 4 subfamilies of Muridae imported into Japan as pets were examined; 5 species of Syphacia (Nematoda: Oxyuridae), Aspiculuris tetraptera (Nematoda: Heteroxynematidae), and Rodentolepis nana (Cestoidea: Hymenolepididae) were collected. Concurrent infection with 3 pinworm species, Syphacia mesocriceti, Syphacia stroma, and Syphacia peromysci, was recorded for the first time in the golden hamster, Mesocricetus auratus. Syphacia mesocriceti was also identified in the desert hamster, Phodopus roborovskii, and S. peromysci was recovered from the fat-tailed gerbil, Pachyuromys duprasi, and the Cairo spiny mouse, Acomys cahirinus. From the pygmy mouse, Mus minutoides, an undetermined species closely resembling Syphacia megaloon and Syphacia ohtaorum, both parasitic in Mus spp., was collected. Females of another undetermined Syphacia sp. were observed in the greater Egyptian gerbil, Gerbillus pyramidum. All of the host-Syphacia associations, except S. mesocriceti in the golden hamsters, were recorded for the first time. It is suggested that overlapping breeding situations provided the opportunity for host switching by the pinworms.     

Torulaspora maleeae sp. nov., a novel ascomycetous yeast species from Japan and Thailand

Nine strains of a new Torulaspora species were isolated from natural samples collected in Japan and Thailand including one strain obtained from a leaf of Rhizophora stylosa (NBRC 11061T), one strain from soil (NBRC 11062), six strains from mosses (ST-14, ST-266, ST-510, ST-511, ST-513 and ST-581) and one strain from sediment in mangrove forest (RV-51). On the basis of morphological, biochemical, physiological and chemotaxonomic characteristics, and the sequence analyses of the D1/D2 domain of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) (ITS1-5.8S rRNA gene-ITS2) region, the nine strains were found to represent a single novel species of the genus Torulaspora, which were named Torulaspora maleeae sp. nov. The type strain is NBRC 11061T (BCC 25515T=CBS 10694T). In the phylogenetic trees based on the sequences of the D1/D2 domain of the LSU rRNA gene, T. maleeae showed a close relationship with the five recognized species of the genus Torulaspora, Torulaspora delbrueckii, Torulaspora franciscae, Torulaspora globosa, Torulaspora microellipsoides and Torulaspora pretoriensis. Torulaspora maleeae differed from the five recognized species of the genus Torulaspora by six to 12 nucleotide substitutions (1.1-2.1%) in the D1/D2 domain of the LSU rRNA gene and by 6.4-11.7% nucleotide substitutions in the ITS (ITS1-5.8S rRNA gene-ITS2) region.     

Differential dephosphorylation of the FcRgamma immunoreceptor tyrosine-based activation motif tyrosines with dissimilar potential for activating Syk

The cell surface-expressed gamma chain of the high affinity receptor for IgE (FcepsilonRI) can be phosphorylated on two tyrosine residues of the immunoreceptor tyrosine-based activation motif (ITAM), leading to recruitment and activation of spleen tyrosine kinase (Syk), a kinase that is essential for mast cell signaling and allergic responses. However, it is not known whether preferential phosphorylation or dephosphorylation of the two individual FcRgamma tyrosines (the N-terminal Tyr47 and C-terminal Tyr58) could regulate Syk activation. Herein we report that phosphorylation of only Tyr58 was able to elicit Syk phosphorylation and a weak rise in intracellular calcium, suggesting that Tyr58 phosphorylation may be distinctively important for Syk activation. In vitro and in vivo studies revealed that both Tyr47 and Tyr58 could be similarly phosphorylated. However, mass spectrometric analysis of the phosphorylated FcepsilonRgamma from bone marrow-derived mast cells showed that phosphorylation at Tyr47 was at least 2-fold greater than at Tyr58. This suggested that, once phosphorylated, Tyr58 is preferentially dephosphorylated. In vitro studies demonstrated more efficient dephosphorylation of Tyr58 (by the receptor-associated phosphatases SHP-1 and SHP-2) than of Tyr47. Analysis of Syk binding to wild type and mutant phosphorylated FcepsilonRI revealed that mutation at Tyr58 almost completely ablated Syk binding, whereas mutation at Tyr47 moderately reduced Syk binding. The findings argue for a novel regulatory mechanism, where dephosphorylation of phospho-Tyr58 is likely to promote the down-regulation of Syk activation and suppression of mast cell responses.     

Protein kinase B (PKB/Akt) is required for the completion of meiosis in mouse oocytes

Akt, also known as protein kinase B, is implicated in many cellular processes. Akt is phosphorylated at two residues, Thr308 and Ser473. Thr308-phosphorylated Akt is present in pericentriolar materials, while localization of Ser473-phosphorylated Akt was similar to that of microtubules in metaphase oocytes. Spindles were shorter and aberrant in oocytes injected with Thr308- or Ser473-phosphorylated Akt antibodies. Specifically, Thr308- and Ser473-phosphorylated Akts function individually and are both necessary to assemble the metaphase II (MII) spindle. Moreover, the functions of Thr308- and Ser473-phosphorylated Akts differ in MII oocytes. Although oocytes exhibited second polar body (PB2) emission after the injection of a peptide for Thr308, the chromosomal alignment and microtubular organization were aberrant. In contrast, the injection of a peptide for Ser473 caused a failure of PB2 emission. These results suggest that Thr308- and Ser473-phosphorylated Akts are individually involved in fertilization to complete meiosis, including different roles (i.e., Ser473-phosphorylated Akts are involved in PB2 emission, whereas Thr308-phosphorylated Akts regulate the organization of microtubules).