Arpp,a new homolog of carp,is preferentially expressed in type 1 skeletal muscle fibers and is markedly induced by denervation

In this study, we isolated and characterized a murine counterpart of the human Arpp (hArpp) gene. Sequence analysis revealed that the murine Arpp (mArpp) gene is almost identical to the Ankrd2 gene, which has recently been isolated as a mouse gene induced in stretched skeletal muscle. The mArpp gene encodes a protein of 332 amino acids that contains four well-conserved ankyrin-repeat domains in the central portion of the protein. The amino acid sequence of mArpp protein (mArpp) is highly homologous to that of mouse cardiac-restricted ankyrin-repeat protein (Carp), which is proposed to be a putative genetic marker for cardiac hypertrophy. Immunohistochemical analysis revealed that mArpp is preferentially expressed in type 1 skeletal muscle fibers, and that mArpp is localized in both the nucleus and the sarcomeric I-band of muscle fibers, suggesting that Arpp may function as a nuclear and sarcomeric protein. Furthermore, mArpp was also expressed in neurons of the cerebellum and cerebrum, the islets of Langerhans in the pancreas, and the esophageal epithelium, suggesting that mArpp may play a functional physiologic role in brain, pancreas, and esophagus as well as in type 1 muscle fibers. Interestingly, although mArpp was localized in both nucleus and cytoplasm in neurons, its localization was restricted to nucleus in pancreas and esophagus, suggesting that intracellular localization of mArpp is regulated in a tissue-specific manner. Furthermore, we found that mArpp- and Carp-expression in skeletal muscle were markedly up-regulated after denervation. Although the elevated expression level of Carp was kept only for two weeks after denervation, that of Arpp was kept at least for 4 weeks, suggesting that mArpp and Carp may play distinct functional roles in denervated skeletal muscle.     

Epitope analysis of HLA-DR-restricted helper T-cell responses to Der p II, a major allergen molecule of Dermatophagoides pteronyssinus

T-cell epitopes of Der p II, a major allergen of Dermatophagoides pteronyssinus , were analyzed by using human T-cell clones. We tested 38 cloned T cells from two Japanese patients with allergic rhinitis, and identified at least two peptides (K33-T47 and 158-C73) as helper T-cell epitopes. The former epitope was shown to be restricted by HLA-DRB1* 1502, and the latter by HLA-DRB1* 0405, both of which are typical Japanese HLA-DR alleles, suggesting that those T-cell epitopes might be important for the onset of house-dust mite allergy in the Japanese population. We prepared 15 analog peptides of the HLA-DRB1* 1502-restricted 15-mer peptide. Of those 15 residues, five (F35, L37, A39, F41, and E42) were critical for the epitope activity, and three residues (F35, A39, and E42) seemed to be included in anchor motifs for HLA-DRB1* 1502. The epitope peptide was also recognized by HLA-DRB1* 1502-positive healthy donors; however, only allergic T cells showed Th2 functions. Antigen-presenting cells of nonallergic donors were able to activate allergic T cells to express Th2 function. This seemed to suggest that antigen recognition of T cells, as well as additional unknown factors which promote Th2, rather than Th1, responses, might be important for the onset of house-dust mite allergy.     

Ultrastructure of human pheochromocytoma cells cultured for long periods

We conducted ultrastructural analysis of human pheochromocytoma (PC) cells maintained in primary culture for about 10 months. The cells were first isolated by the enzymatic treatment of a surgically resected tissue specimen obtained from a 37-year-old man with PC, a condition which is characterized by elevated blood levels of adrenaline and noradrenaline. It was found that noradrenaline production in the medium continued until the 90th day of culture (1330 pg/ml). The production level decreased to 20 pg/ml on the 180th day, and to 18 pg/ml on the 300th day. Examination under a transmission electron microscope (TEM) at 4 weeks of culture revealed electron-dense granules (about 200 nm in size and, presumably, rich in catecholamines), which were also observed in the tumor cells from the original PC tissue. Neurite-like processes grew at around 1 week of culture, and were still maintained at 6 months of culture. But, after 6 months of culture, the neurite-like processes contained a rosary-like elevated structure, which was suggestive of cell degeneration, as determined by a plasma polymerization replica method and observed with a scanning electron microscope. When cells were examined under the TEM, fewer electron-dense granules were observed in the cell bodies, with more numerous lipofuscin-like granules and filaments. Thus, electron-dense granules, which, presumably, contain catecholamines, were seen in a long-term culture of human PC cells. These granules decreased in number in parallel with the decrease in catecholamine levels in the culture.     

Cardiac ankyrin repeat protein is preferentially induced in atrophic myofibers of congenital myopathy and spinal muscular atrophy

Cardiac ankyrin repeat protein (CARP), which is structurally characterized by the presence of four ankyrin repeat motifs in its central region, is believed to be localized in the nucleus and to participate in the regulation of cardiac-specific gene expression in cardiomyocytes. However, we recently found that CARP was induced in skeletal muscle by denervation, leading us to speculate that CARP may be induced under some pathological conditions. In the present study, we immunohistochemically analyzed the expression of CARP in 11 cases of spinal muscular atrophy (SMA) and 14 cases of congenital myopathy. In SMA, CARP was expressed selectively in severely atrophic myofibers, suggesting that CARP expression may reflect the status of muscle atrophy. Furthermore, in the congenital myopathies, the expression patterns of CARP were distinct among the subtypes, which included nemaline myopathy, myotubular myopathy, central core disease, and congenital fiber type disproportion. Although CARP was preferentially expressed in severely damaged myofibers in nemaline myopathy, it was not detected in central core disease. These findings suggest that immunohistochemical evaluation of CARP may be helpful in the diagnosis of SMA and the congenital myopathies.     

Effect of maximal arm exercise on skin blood flux in the paralyzed lower limbs in persons with spinal cord injury

 The purpose of the present study was to examine the effect of maximal arm exercise on the skin blood circulation of the paralyzed lower limbs in persons with spinal cord injury (PSCI). Eight male PSCI with complete lesions located between T3 and L1 performed graded maximal arm-cranking exercise (MACE) to exhaustion. The skin blood flux at the thigh (SBFT) and that at the calf (SBFC) were monitored using laser-Doppler flowmeter at rest and for 15 s immediately after the MACE. The subject's mean peak oxygen uptake and peak heart rate was 1.41 ± 0.22 l · min^–1 and 171.6 ± 19.2 beats · min^–1, respectively. No PSCI showed any increase in either SBFT or SBFC after the MACE, when compared with the values at rest. These results suggest that the blood circulation of the skin in the paralyzed lower limbs in PSCI is unaffected by the MACE. Accepted: 12 September 1996     

The role of IL-17 in systemic lupus erythematosus and its potential as a therapeutic target

Introduction: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibodies production and immune complex deposition with systemic clinical manifestations. Interleukin (IL)-17-producing cells play a crucial role in disease pathogenesis and represent an attractive therapeutic target.

Areas covered: This review provides an update on the possibility of targeting IL-17 in SLE. The rational for this approach as well as currently available and future targets are discussed.

Expert opinion: Although human expression studies and animal models indicate that IL-17 blocking may be a promising therapeutic strategy for SLE, direct evidence for IL-17 inhibition in SLE patients is unavailable. Biologic therapies and small-molecule drugs that target IL-17 production are required for the achievement of a favorable clinical effect in SLE patients.     

Dominant-negative hypoxia-inducible factor-1 alpha reduces tumorigenicity of pancreatic cancer cells through the suppression of glucose metabolism

In the tumor cells exposed to hypoxia, hypoxia-inducible factor-1 (HIF-1)-mediated adaptation responses such as angiogenesis and anaerobic metabolism are induced for their survival. We have recently reported that the constitutive expression of HIF-1 alpha renders pancreatic cancer cells resistant to apoptosis induced by hypoxia and glucose deprivation. We then established dominant-negative HIF-1 alpha (dnHIF-1 alpha) transfectants and examined their susceptibility to apoptosis and growth inhibition induced by hypoxia and glucose deprivation in vitro and their tumorigenicity in SCID mice. We further examined the expressions of aldolase A and Glut-1 in vitro and Glut-1 expression and glucose uptake in the tumor tissues and microvessel counts in the tumor tissues. As a result, dnHIF-1 alpha rendered the pancreatic cancer cells sensitive to apoptosis and growth inhibition induced by hypoxia and glucose deprivation. Also it abrogated the enhanced expression of Glut-1 and aldolase A mRNAs under hypoxia and reduced the expression of Glut-1 and the glucose uptake in the tumor tissues and consequently in vivo tumorigenicity. We found no significant difference in the microvessel counts among the tumor tissues. From these results, we suggest that the disruption of the HIF-1 pathway might be effective in the treatment of pancreatic cancers.     

Connexin 26 distribution in gap junctions between melanocytes in the human vestibular dark cell area

We have previously demonstrated the presence of gap junctions between melanocytes in the human vestibular organ and have speculated that melanocytes function in maintaining the homeostasis of the microenvironment of the inner ear. The purpose of the present study was to characterize the expression and ultrastructural localization of connexin (Cx) protein in melanocytes of the human vestibular organs. Surgical material was obtained from patients operated on for vestibular schwannoma and was processed for light microscopy, confocal laser scanning microscopy, conventional TEM, and immuno TEM. The specimens were labeled with anti-Cx26, Cx32, and Cx43 antibodies and examined by light microscopy. Specimens were also labeled with anti-Cx26 antibody and examined by laser microscopy and immuno-TEM methods. The specimens examined in this study were mainly dark cell areas from the human vestibular organ, whose epithelial and subepithelial layers are rich in melanocytes. Light-microscopic immunohistochemical studies showed positive labeling for Cx26 protein between subepithelial melanocytes, and Cx32 was also detected. Use of anti-Cx26 antibody and confocal laser scanning microscopy revealed high levels of Cx26 around the subepithelial melanocytes. Post-embedding immuno-gold transmission electron microscopy showed significant aggregation of gold particles (33.97 +/- 8.01% of total gold particles) around the gap junctions of the subepithelial melanocytes. The results of this study indicated that melanocytes are connected through gap junctions that mainly contain Cx26. This suggested that the melanocytes in the human vestibular organ may play a role in transporting material between the endolymph and perilymph.     

Infectious influenza A and B virus variants with long carboxyl terminal deletions in the NS1 polypeptides

An influenza A virus, A/turkey/Oregon/71, was shown by protein gel analysis to code for an NS1 protein approximately half the size of those of other influenza A viruses. Sequence analysis of the NS gene of this virus revealed a 10 nucleotide deletion resulting in an NS1 protein of only 124 amino acids. This truncated NS1 polypeptide retained its karyophilic pattern as detected by indirect immunofluorescence analysis of virus infected cells. Also, A/turkey/Oregon/71 virus grew to high titer in embryonated chicken eggs comparable to other influenza A viruses. We also identified a laboratory variant of an influenza B virus, clone 201, which codes for a truncated NS1 protein. Sequence analysis revealed a 13 nucleotide deletion resulting in a shortened NS1 protein of only 127 amino acids as compared to other influenza B virus NS1 proteins possessing a length of 281 amino acids. Again as shown for the NS1 proteins of other influenza B viruses the NS1 polypeptide of B virus clone 201 was found to localize in the nucleus of infected cells. It appears that large deletions in the carboxyl terminus of the NS1 proteins of influenza A and B viruses can be tolerated without affecting the functional integrity of the NS1 polypeptide.