Taurine-Responsive Genes Related to Signal Transduction as Identified by cDNA Microarray Analyses of HepG2 Cells

Abstract

Taurine-induced changes in the expression profiles of HepG2 cells were assessed using a cDNA microarray technology, and confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses. Of 8,298 human genes on the microarray, 128 genes (87 known genes) were up-regulated, and 349 (206 known genes) were down-regulated more than 2.0-fold by taurine. Among the 293 known genes regulated by taurine, a total of 44 genes were involved in signal transduction; 16 genes were up-regulated greater than 2.0-fold, and 28 genes were down-regulated more than 2.0-fold by taurine. The results of RT-PCR analyses for the five genes selected were consistent with our microarray data, although the fold changes in the expression level differed somewhat between the two analytical methods. Among signal transduction-related genes affected by taurine, four genes--mitogen-activated protein kinase (MAPK) kinase kinase 7, p21-activated kinase 4, sprouty homolog 2, and MAPK kinase 1--are implicated in the MAPK signaling pathway. Taurine also regulated the expression of signal transducer and activator of transcription (STAT) 3 gene involved in the Janus kinase-STAT pathway, and diacylglycerol kinase, zeta 104 kDa, the downstream mediator of the protein kinase C transmembrane signaling pathway. In conclusion, gene expression profiling of HepG2 cells treated with taurine provided us with new insights into the novel aspects of taurine as a possible regulator of MAPK signaling cascades and protein kinase C signaling pathways involved in cellular processes such as cell growth, differentiation, and apoptosis.

Neuroprotective Mechanism of Taurine due to Up-regulating Calpastatin and Down-regulating Calpain and Caspase-3 during Focal Cerebral Ischemia

“…However, our results do not exclude the increase in calpastatin expression during focal cerebral ischemia. The mechanism by which taurine increases calpastatin actions is unclear, which might be related to the up-regulation of gene expression by taurine (Park et al 2006), or down-regulation of calpain and caspase-3 activation by taurine, as demonstrated in this study. Further study is needed to determine the mechanism by which taurine up-regulates the calpastatin actions during focal cerebral ischemia.…”

Metabolic changes in visual cortex of neonatal monocular enucleated rat: a proton magnetic resonance spectroscopy study

“…Physiological roles of Tau include membrane stabilization, osmoregulation, neuromodulation, regulation of calcium homeostasis, and antioxidation (Bouckenooghe et al, 2006). Previous study also showed that Tau might act on various cellular processes such as proliferation, differentiation and inhibition of apoptosis (Park et al, 2006). Reduced Tau signal in degenerating rat brain with Alzheimer's disease was also reported recently using 1 H MRS (Labak et al, 2010).…”

Taurine transport in human placental trophoblast is important for regulation of cell differentiation and survival

“…In non-placental cells, intracellular taurine modulates the expression and phosphorylation of proteins involved in the MAPK, STAT3 and PKC signalling pathways. 21 Each of these signalling molecules are involved in cell differentiation, 22, 23, 24 therefore, alterations in intracellular taurine could affect their role in this process. Alternatively, taurine could help maintain gap junctional intercellular communication required for cell fusion, as has been shown in liver.…”