Phosphorylation of c-Jun N-terminal Kinase in Human Hepatoblastoma Cells is Transiently Increased by Cold Exposure and Further Enhanced by Subsequent Warm Incubation of the Cells

Abstract

During a cold preservation and reperfusion process of organs, cells are exposed to two major stresses, i.e. changes in oxygen concentration and temperature. c-Jun N-terminal kinase (JNK) /stress-activated protein kinase is activated by various stresses through its phosphorylation. Although hypoxia and subsequent reoxygenation is known to activate JNK, little is known about effects of hypothermia and subsequent rewarming on JNK activation. Thus, we investigated the activation of JNK in human hepatoblastoma (HepG2) cells exposed to a temperature of 5°C and in those rewarmed at 37°C. Western blot analysis using an anti-phospho-JNK antibody revealed that p54 JNK was transiently phosphorylated in cold-stressed cells. In addition, the phosphorylation of p54 JNK was further increased by rewarming of the cells. Since translational and transcriptional abilities were markedly reduced in the cold-stressed cells, effects of translation and transcription inhibitors on the phosphorylation of p54 JNK were determined. Cycloheximide, but not actinomycin D, increased the phosphorylation of p54 JNK in HepG2 cells. These results suggest that hypothermia alone transiently increases the p54 JNK phosphorylation possibly through reduction of protein synthesis and that rewarming after hypothermia stimulates the phosphorylation of p54 JNK.

Proliferation control strategies to improve productivity and survival during CHO based production culture

“…A change in the phosphorylation patterns at the tyrosine residues of two proteins (~180 and 80 kDa) was also observed following reduction of the culture temperature providing further proof that there is an active signalling response to mild hypothermia in CHO (Kaufmann et al 1999). The effect of reduced temperature on cells is likely to be multifactorial as it also combines the effect of changes in oxygen concentration due to the higher dissolved oxygen concentrations at reduced temperatures (Ohsaka et al 2002).…”

Tuning the critical gelation temperature of thermo-responsive diblock copolymer worm gels

“…Higher CGTs can also be achieved by targeting copolymers with shorter core-forming blocks ( Figure 3). For example, PGMA59-P(HPMA77-stat-DEGMA36), PGMA59-P(HPMA84-stat-DEGMA36) and PGMA59-P(HPMA91-stat-DEGMA39) each exhibit CGT values above 30°C, which should be sufficiently high to minimize thermal shock if these gels were to be used as cell growth media [15][16][17][18][19][20] …”

The cold‐shock response in cultured mammalian cells: Harnessing the response for the improvement of recombinant protein production

“…Cold-stress exposes cells to two major stresses; those relating to changes in temperature and those related to changes in oxygen concentration due to higher dissolved oxygen concentrations at reduced temperatures (Ohsaka et al, 2002). Although our understanding of the cold-shock response in eukaryotes is limited, several studies have demonstrated that induced CSPs are key determinants in the adaptation to growth and survival at lower temperatures (Danno et al, 2000;Nishiyama et al, 1998;Phadtare et al, 1999;Sonna et al, 2002), although little is known about what effect changes in dissolved oxygen concentrations may play in these responses.…”