Limits...
Overexpression of tau downregulated the mRNA levels of Kv channels and improved proliferation in N2A cells.

Li X, Hu X, Li X, Hao X - PLoS ONE (2015)

Bottom Line: Furthermore, the macroscopic currents through Kv channels were reduced by 36.5% at +60 mV in tau-transfected N2A cells.The proliferation rates of N2A cells were also improved by the induction of tau expression and the incubation of TEA (tetraethylammonium) for 48 h by 120.9% and 149.3%, respectively.Following the cotransfection with tau in HEK293 cells, the mRNA levels and corresponding currents of Kv2.1 were significantly declined compared with single Kv2.1 transfection.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, China.

ABSTRACT
Microtubule binding protein tau has a crucial function in promoting the assembly and stabilization of microtubule. Besides tuning the action potentials, voltage-gated K+ channels (Kv) are important for cell proliferation and appear to play a role in the development of cancer. However, little is known about the possible interaction of tau with Kv channels in various tissues. In the present study, tau plasmids were transiently transfected into mouse neuroblastoma N2A cells to explore the possible linkages between tau and Kv channels. This treatment led to a downregulation of mRNA levels of several Kv channels, including Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4, but no significant alteration was observed for Kv5.1 and KCNQ4. Furthermore, the macroscopic currents through Kv channels were reduced by 36.5% at +60 mV in tau-transfected N2A cells. The proliferation rates of N2A cells were also improved by the induction of tau expression and the incubation of TEA (tetraethylammonium) for 48 h by 120.9% and 149.3%, respectively. Following the cotransfection with tau in HEK293 cells, the mRNA levels and corresponding currents of Kv2.1 were significantly declined compared with single Kv2.1 transfection. Our data indicated that overexpression of tau declined the mRNA levels of Kv channels and related currents. The effects of tau overexpression on Kv channels provided an alternative explanation for low sensitivity to anti-cancer chemicals in some specific cancer tissues.

Show MeSH

Related in: MedlinePlus

Expressions of Kv channels were reduced by tau transfection.The induction of tau downregulated the mRNA level of Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4, but no significant changes were found for Kv5.2 and KCNQ4. The statistic analyses of QPCR data were plotted as graph (n = 9). *P<0.05 compared with control.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4295873&req=5

pone.0116628.g003: Expressions of Kv channels were reduced by tau transfection.The induction of tau downregulated the mRNA level of Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4, but no significant changes were found for Kv5.2 and KCNQ4. The statistic analyses of QPCR data were plotted as graph (n = 9). *P<0.05 compared with control.

Mentions: Although previous studies suggested that both tau and Kv channels were involved in regulation of cellular proliferation [22, 28], little is known about possible interaction of tau with Kv channels. In the experiments here, tau was transiently transfected into N2A cells using Lipofectamine 2000 for 48 h. Total tau was detected by Western blotting with antibody Tau-5 (Fig. 2). In agreement with the previous report [25], a weak signal for endogenous tau expression was found in the control and vector group. Apparently, the robust overexpression of tau after transfection was detectable in N2A cells. Subsequently, the alterations of expression of Kv channels in N2A cells were measured by the performance of QPCR. As shown in Fig. 3, overexpression of tau led to a reduction of expression of several different Kv channels, including Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4. It should be noted that this treatment barely affected the mRNA levels of Kv5.1 and KCNQ4. The quantitative analyses of these actions indicated that expressions of Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4, were reduced by 53.9%, 51.9%, 39.0%, 48.3% and 31.3%, respectively. To exclude the effects of empty vector on expression of Kv channels, mock transfections were conducted and no significant alteration was detected by QPCR analysis (data not shown).


Overexpression of tau downregulated the mRNA levels of Kv channels and improved proliferation in N2A cells.

Li X, Hu X, Li X, Hao X - PLoS ONE (2015)

Expressions of Kv channels were reduced by tau transfection.The induction of tau downregulated the mRNA level of Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4, but no significant changes were found for Kv5.2 and KCNQ4. The statistic analyses of QPCR data were plotted as graph (n = 9). *P<0.05 compared with control.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4295873&req=5

pone.0116628.g003: Expressions of Kv channels were reduced by tau transfection.The induction of tau downregulated the mRNA level of Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4, but no significant changes were found for Kv5.2 and KCNQ4. The statistic analyses of QPCR data were plotted as graph (n = 9). *P<0.05 compared with control.
Mentions: Although previous studies suggested that both tau and Kv channels were involved in regulation of cellular proliferation [22, 28], little is known about possible interaction of tau with Kv channels. In the experiments here, tau was transiently transfected into N2A cells using Lipofectamine 2000 for 48 h. Total tau was detected by Western blotting with antibody Tau-5 (Fig. 2). In agreement with the previous report [25], a weak signal for endogenous tau expression was found in the control and vector group. Apparently, the robust overexpression of tau after transfection was detectable in N2A cells. Subsequently, the alterations of expression of Kv channels in N2A cells were measured by the performance of QPCR. As shown in Fig. 3, overexpression of tau led to a reduction of expression of several different Kv channels, including Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4. It should be noted that this treatment barely affected the mRNA levels of Kv5.1 and KCNQ4. The quantitative analyses of these actions indicated that expressions of Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4, were reduced by 53.9%, 51.9%, 39.0%, 48.3% and 31.3%, respectively. To exclude the effects of empty vector on expression of Kv channels, mock transfections were conducted and no significant alteration was detected by QPCR analysis (data not shown).

Bottom Line: Furthermore, the macroscopic currents through Kv channels were reduced by 36.5% at +60 mV in tau-transfected N2A cells.The proliferation rates of N2A cells were also improved by the induction of tau expression and the incubation of TEA (tetraethylammonium) for 48 h by 120.9% and 149.3%, respectively.Following the cotransfection with tau in HEK293 cells, the mRNA levels and corresponding currents of Kv2.1 were significantly declined compared with single Kv2.1 transfection.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, China.

ABSTRACT
Microtubule binding protein tau has a crucial function in promoting the assembly and stabilization of microtubule. Besides tuning the action potentials, voltage-gated K+ channels (Kv) are important for cell proliferation and appear to play a role in the development of cancer. However, little is known about the possible interaction of tau with Kv channels in various tissues. In the present study, tau plasmids were transiently transfected into mouse neuroblastoma N2A cells to explore the possible linkages between tau and Kv channels. This treatment led to a downregulation of mRNA levels of several Kv channels, including Kv2.1, Kv3.1, Kv4.1, Kv9.2, and KCNH4, but no significant alteration was observed for Kv5.1 and KCNQ4. Furthermore, the macroscopic currents through Kv channels were reduced by 36.5% at +60 mV in tau-transfected N2A cells. The proliferation rates of N2A cells were also improved by the induction of tau expression and the incubation of TEA (tetraethylammonium) for 48 h by 120.9% and 149.3%, respectively. Following the cotransfection with tau in HEK293 cells, the mRNA levels and corresponding currents of Kv2.1 were significantly declined compared with single Kv2.1 transfection. Our data indicated that overexpression of tau declined the mRNA levels of Kv channels and related currents. The effects of tau overexpression on Kv channels provided an alternative explanation for low sensitivity to anti-cancer chemicals in some specific cancer tissues.

Show MeSH
Related in: MedlinePlus