Glycate화된 단백질이 혈관질환의 발생에 관여하는지 알아보기 위하여 glycated albumin (GA)이 혈관평활근 세포에서 인터루킨-6 발현에 영향을 주는지 조사하고 또한 그 기전을 구명하였다. GA에 노출된 혈관평활근세포에서 인터루킨-6 transcript가 증가하고, 인터루킨-6 단백질의 분비가 증가하고, 또한 인터루킨-6 유전자의 promoter가 활성화되었다. GA에 의한 인터루킨-6 유전자의 promoter 활성화는 dominant negative 형태의 Toll-like receptor (TLR)-4와 myeloid differentiation factor 88 (Myd88)에 의하여 크게 감소되었지만, dominant negative 형태의 TLR-2와 TIR-domain-containing adapter-inducing interferon-$eta$ (TRIF)의 영향을 받지 않았다. 그리고 Extrcellular signal-related kinase (ERK) 억제 물질들은 GA에 의한 인터루킨-6의 분비 및 인터루킨-6 유전자 promoter 활성화를 억제하였다. 그리고 인터루킨-6 유전자의 promoter의 NF-${kappa}B$-binding sequence에 변이는 GA에 의한 인터루킨-6 유전자의 promoter 활성화 억제하였다. 이러한 결과는 혈관평활근세포에서 GA에 의한 인터루킨-6 유전자 활성화에 TLR-4와 ERK 및 NF-${kappa}B$가 관여함을 의미한다.
Diabetes mellitus is associated with vascular complications. Diabetic patients exhibit high levels of glycated adducts in serum compared to non-diabetic individuals. The aim of this study was to investigate whether extracellular glycated albumin (GA) predisposes vascular smooth muscle cells (VSMCs) to pro-inflammatory phenotype. Exposure of rat aortic smooth muscle cells (AoSMCs) to GA not only enhanced interleukin-6 (IL-6) release but also activated promoter activity of the IL-6 gene. GA-induced IL-6 promoter activation was suppressed by dominant-negative forms of Toll-like receptor (TLR)-4 and myeloid differentiation factor 88 (MyD88), but not by dominant-negative-forms of TLR-2 and TIR-domain-containing adapter-inducing interferon-$eta$ (TRIF). Extracellular signal-regulated kinase (ERK) inhibition and diphenyleneiodium (DPI) also attenuated IL-6 induction by GA. Mutation at the nuclear factor-${kappa}B$ (NF-${kappa}B$)-binding site in the IL-6 promoter region suppressed promoter activation in response to GA. The present study proposes that GA would contribute to inflammatory reaction in the stressed vasculature by inducing IL-6 in VSMCs, and that TLR-4, EKR, and NF-${kappa}B$ play active roles in the process.
