Suppression of age-related renal changes in NF-kappaB and its target gene expression by dietary ferulate.

Ferulate is a well-described natural antioxidant found in plants. It protects against cellular redox disruption and several oxidative stress-related diseases, including inflammation in animal studies. In this study, we examined ferulate for its ability to suppress redox-sensitive, proinflammatory NF-kappaB activation via NF-kappaB-inducing kinase (NIK)/IkappaB kinase (IKK) and mitogen-activated protein kinases (MAPKs) by reducing oxidative stress in aged rats. The experimental design was set as follows: Sprague-Dawley rats, ages 7 months (young) and 20 months (old) were used in this study, and dietary ferulate (0.01% or 0.02%) was fed to the old rats for 10 days. Data show that in aged kidney tissue, ferulate exhibited its antioxidative action by maintaining redox regulation, suppressing NF-kappaB activation and modulating the expression of NF-kappaB-induced, proinflammatory COX-2, iNOS, VCAM-1 and ICAM-1. Next, we examined cultured YPEN-1 endothelial cells and show that ferulate protected YPEN-1 cells against tert-butylhydroperoxide-induced oxidative stress. The molecular modulation of NF-kappaB by ferulate was further revealed in endothelial YPEN-1 cells through ferulate's ability to suppress the activation of NIK/IKK and MAPKs. Based on these results, we conclude that ferulate's antioxidative capacity suppressed the age-related increase in NF-kappaB activity through inhibition of NIK/IKK and MAPKs in vivo. This study may also suggest the potentiality of ferulate as a developable supplement against chronic inflammatory disease as well as aging.

Betaine modulates age-related NF-kappaB by thiol-enhancing action.

Depletion of glutathione levels and perturbations in redox status are considered to play a crucial role in aging and chronic inflammatory processes through the activation of redox sensitive transcription factors, including nuclear factor-kappaB (NF-kappaB). In the current study, we assessed the regulatory action of dietary betaine in the suppression of NF-kappaB by comparing kidney tissue from old, betaine-supplemented rats or non-betaine-supplemented rats (age 21 months) and 7 month-old rats. In addition, cultured HEK 293T cells were utilized for the molecular assessment of betaine's restorative ability of redox status when treating cells with potent glutathione (GSH)-depleting agents. Results showed that in old rats a short-term feeding (10 d) with betaine attenuated the age-related decrease in thiol levels, increase in reactive species and TNFalpha expression via NF-kappaB activation, compared to the young controls. These findings were verified in the cell-cultured system. Further investigations found that redox imbalance due to thiol depletion caused increased NF-kappaB activation, and cyclooxygenase (COX)-2 and TNFalpha levels, both of which were suppressed by betaine treatment. Based on both in vivo and in vitro data, we concluded that betaine exerts its efficacy by maintaining thiol status in the regulation of COX-2 and TNFalpha via NF-kappaB activation during aging.

Betaine suppresses proinflammatory signaling during aging: the involvement of nuclear factor-kappaB via nuclear factor-inducing kinase/IkappaB kinase and mitogen-activated protein kinases.

Betaine is an important human nutrient obtained from various foods. In the present study, we assessed the anti-inflammatory effect of betaine on nuclear factor-kappaB (NF-kappaB) during aging. Sprague-Dawley (SD) rats, ages 7 and 21 months, were used in this study. The older rats were fed betaine. To elucidate the effect of betaine on oxidative stress-induced NF-kappaB and its signaling pathway at molecular levels, YPEN-1 cells were used. Results showed that betaine suppressed NF-kappaB and its related gene expressions of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), vascular cell adhesion molecule-1 (VCAM-1), and intracellular cell adhesion molecule-1 (ICAM-1) in aged kidney. Furthermore, betaine attenuated oxidative stress-induced NF-kappaB via nuclear factor-inducing kinase/IkappaB kinase (NIK/IKK) and mitogen-activated protein kinases (MAPKs) in the YPEN-1 cells. On the basis of these results, we concluded that betaine suppressed the age-related NF-kappaB activities associated with upregulated NIK/IKK and MAPKs that were induced by oxidative stress. Thus, betaine might be useful as a preventive agent against the activation of NF-kappaB induced during inflammation and aging.

NF-kappaB activation mechanism of 4-hydroxyhexenal via NIK/IKK and p38 MAPK pathway.

4-Hydroxyhexenal (HHE) is known to affect redox balance during aging, included are vascular dysfunctions. To better understand vascular abnormality through the molecular alterations resulting from HHE accumulation in aging processes, we set out to determine whether up-regulation of mitogen-activated protein kinase (MAPK) by HHE is mediated through nuclear factor kappa B (NF-kappaB) activation in endothelial cells. HHE induced NF-kappaB activation by inhibitor of kappaB (IkappaB) phosphorylation via the IkappaB kinase (IKK)/NF-kappaB inducing kinase (NIK) pathway. HHE increased the activity of p38 MAPK and extracellular signal regulated kinase (ERK), but not c-jun NH(2)-terminal kinase, indicating that p38 MAPK and ERK are closely involved in HHE-induced NF-kappaB transactivation. Pretreatment with ERK inhibitor PD98059, and p38 MAPK inhibitor SB203580, attenuated the induction of p65 translocation, IkappaB phosphorylation, and NF-kappaB luciferase activity. These findings strongly suggest that HHE induces NF-kappaB activation through IKK/NIK pathway and/or p38 MAPK and ERK activation associated with oxidative stress in endothelial cells.