👤 Atsushi Fukagawa

To investigate differential gene expression profiles in the bladder of spontaneously hypertensive rat (SHR), as the underlying mechanisms involved in hypertension-associated bladder dysfunction remain to be clarified. SHR and normotensive Wistar-Kyoto (WKY) rats were distributed initially in three groups: group 1 received doxazosin (30 mg/kg/day); group 2 received nifedipine (30 mg/kg/day); and group 3 received the vehicle orally for 4 weeks. The alterations in gene expression levels of candidate genes identified by microarray analysis with potential biological relevance were verified by real-time reverse transcription-polymerase chain reaction (RT-PCR). Voiding frequency was significantly higher, and mean voided volume was significantly lower in untreated SHRs than untreated WKY rats. Microarray analysis revealed that 25 of the differentially expressed genes in untreated SHRs compared to untreated WKY rats were related to G(s), G(i), G(q) and G(12/13) signalling, calcium handling, ion transport and smooth muscle-related genes. Furthermore, RT-PCR data, in accord with the microarray analysis, indicated that untreated SHRs had lower mRNA expression levels of Adcy2, Adcy3, Rgs2, Rgs3, Rgs4 and Arhgdia, and higher mRNA expression levels of Arhgef1, Arhgef11, Arhgef12, Geft, Rock1 and Rock2 than untreated WKY rats. The differential alterations in the micturition patterns and in the expression of several genes related to G-protein signalling pathway observed in SHRs were attenuated by treatment with doxazosin, but not nifedipine. Our data suggest that differential alterations in the expression of several genes related to G(s), G(q) and G(12/13) signalling pathways in the SHR bladder might be important in hypertension-associated bladder dysfunction. Show less

We previously demonstrated that a fraction of the human Nup107-160 nuclear pore subcomplex is recruited to kinetochores at the onset of mitosis. However, the molecular determinants for its kinetochore targeting and the functional significance of this localization were not investigated. Here, we show that the Nup107-160 complex interacts with CENP-F, but that CENP-F only moderately contributes to its targeting to kinetochores. In addition, we show that the recruitment of the Nup107-160 complex to kinetochores mainly depends on the Ndc80 complex. We further demonstrate that efficient depletion of the Nup107-160 complex from kinetochores, achieved either by combining siRNAs targeting several of its subunits excluding Seh1, or by depleting Seh1 alone, induces a mitotic delay. Further analysis of Seh1-depleted cells revealed impaired chromosome congression, reduced kinetochore tension and kinetochore-microtubule attachment defects. Finally, we show that the presence of the Nup107-160 complex at kinetochores is required for the recruitment of Crm1 and RanGAP1-RanBP2 to these structures. Together, our data thus provide the first molecular clues underlying the function of the human Nup107-160 complex at kinetochores. Show less

We tested whether secretion of apolipoprotein (apo) A-IV depends upon intestinal triglyceride (TG) transport by comparing output kinetics of TG and apo A-IV during and after duodenal lipid infusion in lymph-fistula rats. Lipid infusion (triolein, 40 mumol/h, 8 h) produced increases in lymphatic TG and apo A-IV output. After 8 h, triolein infusate was replaced with glucose-saline; TG output returned to basal levels 4-5 h later. However, apo A-IV output continued at significantly elevated levels until 20 h after the start of the experiment. Bile diversion blocked this continued output of A-IV during the post-lipid period, and resulted in basal TG output that was 75% lower than in bile-intact rats. Return of bile or low-dose triolein infusion (5 mumol/h) into the intestine reversed these effects. There were no differences in hepatic synthesis or filtration of plasma A-IV into lymph between bile-intact and bile-diverted groups. Intestinal A-IV synthesis was elevated in both groups even during the post-lipid period. The results support the hypothesis that intestinal triglyceride transport drives apo A-IV secretion, and suggest the existence of a bile-dependent, post-translational mechanism for the control of lymphatic apo A-IV output. Show less