Palmitik Asit AML12 Karaciğer Hücrelerinde Endoplazmik Retikulum Stresi Uyarır

Amaçlar: Nonalkolik yağlı karaciğer hastalığı (NAYKH), serum ve karaciğerde artmış yağ asit seviyeleri ile karakterizedir. NAYKH’nin mekanizması net değildir. Endoplazmik retikulum (ER) stresin rolü dikkat çekmektedir. Bu çalışmanın ilk amacı, bir in vitro NAYKH modeli dizayn etmekti. İkinci hedef olarak, palmitik asid (PA)’in yalnız veya oleik asit (OA) ile kombinasyonunun, karaciğer hücrelerinde, reaktif oksijen türleri (ROT) oluşumu ve ER stresi üzerindeki etkileri araştırıldı. Gereçler ve Yöntemler: AML12 hücreleri, farklı konsantrasyon ve kombinasyonlarda, OA ve PA ile muamele edildi. Hücre içi lipidler ve hücre canlılığı, sırasıyla Oil red O boyaması ve WST-1 analiziyle saptandı. Hücre içi ROT birikimi akış sitometrisi ile ölçüldü. ER stres proteinleri, BiP ve IRE1, western blot analizi ile değerlendirildi. Bulgular: Hücre içi lipit içeriği tüm uygulamaya maruz kalmış gruplarda arttı. PA ile muamele edilmiş hücrelerde, hücre canlılığı azaldı ve ROT üretimi ve ER stres proteinlerin ekspresyonu arttı. Ancak bu etkiler OA+PA kombinasyonu ile muamele edilmiş hücrelerde gözlenmedi. Sonuç: PA, karaciğer hücrelerinde, ROS üretimini ve IRE1 aracılı ER stres yolağını indükler. Ama OA eklenmesi bu etkileri iyileştirir.

Anahtar Kelimeler:

Nonalkolik yağlı karaciğer hastalığı, palmitik asit, oleik asit, endoplazmik retikulum stres

Palmitic Acid Induces Endoplasmic Reticulum Stress In AML12 Liver Cells

Objectives: Nonalcoholic fatty liver disease (NAFLD) is characterized by increased fatty acid levels in serum and liver. The mechanism of NAFLD is unclear. The role of endoplasmic reticulum (ER) stress attracts attention. First aim of this study was to design an in vitro NAFLD model. The effects of palmitic acid (PA) alone or combination with oleic acid (OA) on intracellular reactive oxygen species (ROS) production and ER stress in liver cells were investigated as a second aim. Materials and Methods: AML12 cells were exposed to PA and/or OA with different concentrations and combinations. Intracellular lipids and cell viability were detected with Oil red O staining and WST-1 assay respectively. Intracellular ROS accumulation was measured by flow cytometry analysis. Expression of ER stress proteins, BiP and IRE1, were evaluated with western blot analysis. Results: Intracellular lipid content was increased in all treated groups. Cell viability was decreased whereas ROS generation and expression of the ER stress proteins were increased in cells treated with PA. However these effects were not observed in the cells treated with OA+PA combination. Conclusion: PA induces ROS generation and the ER stress pathway that is mediated by IRE1 in liver cells. Addition of OA enhances these effects.

Keywords:

Nonalcoholic fatty liver disease, palmitic acid, oleic acid, endoplasmic reticulum stress,

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