Search

Recent studies indicated that Gene Associated with Retinoid-IFN-Induced Mortality 19 (GRIM-19), a newly discovered mitochondria-related protein, can regulate mitochondrial function and modulate cell viability possibly via interacting with STAT3 signal. In the present study we sought to test: 1) whether GRIM-19 is involved in high glucose (HG) induced altered cell metabolism in both cancer and cardiac cells, 2) whether GRIM-19/STAT3 signaling pathway plays a role in HG induced biological effects, especially whether AMPK activity could be involved. Our data showed that HG enhanced cell proliferation of both HeLa and H9C2 cells, which was closely associated with down-regulated GRIM-19 expression and increased phosphorylated STAT3 level. We showed that GRIM-19 knock-down alone in normal glucose cultured cells can also result in an increase in phosphorylated STAT3 level and enhanced proliferation capability, whereas GRIM-19 over-expression can abolished HG induced STAT3 activation and enhanced cell proliferation. Importantly, both down-regulated or over-expression of GRIM-19 increased lactate production in both HeLa and H9C2 cells. The activated STAT3 was responsible for increased cell proliferation as either AG-490, an inhibitor of JAK2, or siRNA targeting STAT3 can attenuate cell proliferation increased by HG. In addition, HG increased lactate acid levels in HeLa cells, which was also observed when GRIM-19 was genetically manipulated. However, HG did not affect the lactate levels in H9C2 cells. Of note, over-expression of GRIM-19 and silencing of STAT3 both increased lactate production in H9C2 cells. As expected, HG resulted in significant decreases in phosphorylated AMPKα levels in H9C2 cells, but not in HeLa cells. Interestingy, activation of AMPKα by metformin was associated with a reversal of the suppressed GRIM-19 expression in H9C2 cells, the fold of changes in GRIM-19 expression by metformin were much less in HeLa cells. Metformin did not affect the phosphorylated STAT3 lelvels, however, decreased its levels in H9C2, especially in the setting of HG culture. Not like HG alone which resulted in no changes in lactate acid in H9C2 cells, metformin can increase lactate acid levels in H9C2 cells. Increased lactate induced by metformin was also observed in HeLa cells.

Abstract: The piezoresistive devices with the structure of ITO/poly(3‐hexylthiophene) (P3HT; spin coating 90 nm film)/Al (75 nm) have been fabricated and measured. We measured the I‐V characteristics of the devices under different stresses. The stress ranges from 0 to 510 kPa and the voltage ranges from 0 to 5 V. The resistance of the devices is very sensitive to the applied stress. The piezoresistive coefficient is far larger than 10−4/Pa when the working voltage ranges from 0.2 to 0.5 V and the stress ranges from 160 to 510 kPa, whereas the current seems to change linearly with pressure and with a considerable fluctuation. This uncertainty in piezoresistance measurement may have originated from the viscoelasticity of P3HT, including a significant creep and a slow restoration after a deep compression, which has been confirmed by the results of the nanoindentation test. In general, P3HT could be used in tactile sensors, which need more sensitivity rather than accuracy. [ABSTRACT FROM AUTHOR]

A diagram is presented which shows the electrocatalytic azidination of alkenes mediated by the compound n-Bu4NI.