Role of Lysyl Oxidase Family during Odontoblastic Differentiation of Human Dental Pulp Cells Induced with Odontogenic Supplement

인간치수세포에서 상아모세포의 분화과정 동안 Lysyl Oxidase Family의 역할

  • Lee, Hwa-Jeong (Department of Maxillofacial Tissue Regeneration, School of Dentistry, Kyung Hee University) ;
  • Han, Soo-Yeon (Department of Dental Hygiene, Hyejeon College)
  • 이화정 (경희대학교 치의학전문대학원 악안면재생학교실) ;
  • 한수연 (혜전대학교 치위생과)
  • Published : 2013.09.30

Abstract

Lysyl oxidase (LOX), extracellular matrix enzyme, is catalyzing lysine-derived crosslinks in collagen and elastin. Recently, several LOX-like proteins (LOXL, LOXL2, LOXL3 and LOXL4) have been identified in human but their specific functions are still largely unknown. The purpose of this study was to evaluate the function of the LOX family genes during odontoblastic differentiation of human dental pulp (HDP) cells induced with odontogenic supplement (OS). The messenger RNA (mRNA) expression of LOX family genes and differentiation markers was assessed by reverse transcriptase polymerase chain reaction analysis (RT-PCR). The formation of mineralization nodules was evaluated by alrizarin red S staining. Amine oxidase activity of HDP cells was measured by peroxidase-coupled fluormetric assay. The expressions of differentiation markers, such as alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), dentin matrix protein1 (DMP1), dentin sialophosphoprotein (DSPP) in HDP cells were increased after treatment with OS media. The LOX and LOXL mRNA expression were gradually increased in OS media, whereas LOX enzyme activities were markedly detected on day 7. The mRNA expression and LOX enzyme activity of collagen type I was very similar to the pattern of LOX gene. In this study, the expression of LOX and its isoforms, and activity of LOX were highly regulated during odontoblastic differentiation. Thus, these results suggest that LOX plays a key role in odontoblastic differentiation of HDP cells.

LOX는 결합조직의 세포외기질에 존재하여 교원섬유와 탄성섬유의 교차결합을 촉진시키는 핵심적인 효소이다. 뼈세포에서 세포분화 및 세포이동과 관련된 LOX의 역할은 보고되었으나, 상아모세포 분화에서 LOX에 대한 직접적인 효과는 거의 알려지지 않았다. 이 연구에서는 인간치수세포에서 상아모세의 분화과정 동안 LOX의 역할에 대해 실험하였다. 치수세포에 저 혈청 분화유도 배지를 처리하여 0, 1, 3, 7, 14일 동안 배양하였다. 세포성장은 세포계수, 분화와 관련된 유전자들은 RT-PCR, 광물화는 alrizarin red S 염색으로 각각 실험하였다. LOX 유전자 발현은 RT-PCR로 측정하였고, LOX 효소활성은 고감도 형광분석을 시행하였다. 1. 세포성장은 저 혈청 분화유도 배지에서 시간 의존적으로 증가하였다. 2. 분화표지자인 ALP, OPN, OCN, DMP1, DSPP는 시간 의존적으로 발현되었으나 초기, 중기, 말기에 대한 차별화는 이루어지지 않았다. 3. 광물화는 3일부터 관찰되기 시작하여 14일까지 증가되었다. 4. LOX와 LOXL은 mRNA 발현이 7일까지 증가되었고, 14일에서 큰 감소를 보였다. 하지만, LOXL3와 LOXL4 mRNA는 낮은 발현을 보였고, LOXL2 mRNA는 발현되지않았다. 5. Collagen type I mRNA는 7일까지 증가하다가 14일에서 의미있게 감소를 보였고, collagen type IV는 낮은 mRNA 발현을 보였다. 6. LOX 효소 활성은 분화유도기간 중 7일에서 가장 많은 발현을 보였고, 교원질 1형 기질이 교원질 IV형 기질보다 두드러진 발현을 보였다. 이상의 결과를 종합해 볼 때, LOX isoform의 발현과 LOX 효소 활성은 인간치수세포에서 상아모세포 분화과정 동안 중요한 조절자로 사료된다.

Keywords

References

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