Sains Malaysiana 49(10)(2020): 2433-2442

http://dx.doi.org/10.17576/jsm-2020-4910-09

High-Dose Edible Bird’S Nest Extract (EBN) Upregulates LDL-R via Suppression of HMGCR Gene Expression in HepG2 Cell Lines

(Sarang Burung Walet (EBN) Berdos Tinggi Meningkatkan LDL-R melalui Perencatan Gen HMGCR dalam Sel HepG2)

MOHD NOOR AKMAL¹, ABDUL RAZAK INTAN-SHAMEHA¹, ROZAIHAN MANSOR^1,2,3, AINI IDERIS^1,2,3, ABDUL RAHMAN OMAR^1,2,3, JALILA ABU^1,3 MOHD FAIZ IDRIS⁴ & MOKRISH AJAT^1,2,3*

¹Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia

²Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia

³Center of Excellence on Swiftlets, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia

⁴Pusat Bahasa dan Pengajian Umum, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak Darul Ridzuan, Malaysia

Received: 22 January 2020/Accepted: 7 May 2020

ABSTRACT

Edible bird’s nest (EBN) is an ancient food that had been consumed by Chinese people for well-being purposes. Nevertheless, the effect of EBN on cholesterol metabolism is poorly studied. Since the cholesterol is primarily being metabolized in the liver, HepG2 cell lines was selected as the model for in-vitro preliminary assessment. Our EBN extract (EBNE) showed 71% cell viability in HepG2 cell lines, even at the highest dose (1.5 mg/mL). Simultaneously, EBNE was significantly up-regulated the LDL-R gene expression via suppression of HMGCR at the highest concentration. Besides that, ACAT2 was up-regulated significantly to allow exogenous cholesterol storage. Expression analysis of these genes were correlated with high immunofluorescence distribution of the LDL-R and LDs compared to other treatment groups. Consistent with gene expression and immunofluorescence staining, intrahepatocellular cholesterol concentration was increased significantly at the highest dose of EBNE. The EBNE had significantly improved cholesterol metabolism in the HepG2 cell line via suppression of the HMGCR gene and subsequently up-regulated LDL-R gene expression at the highest dose. Therefore, this study provides an insight to understand the effect of EBNE in improving cholesterol metabolism.

Keywords: 3-hydroxy-3-methylglutharaldehyde CoA reductase (HMGCR); cholesterol metabolism; edible bird’s nest (EBN); HepG2; low-density lipoprotein receptor (LDL-R)

ABSTRAK

Sarang burung Walet (EBN) merupakan makanan tradisi yang diamalkan oleh masyarakat China bagi tujuan kesihatan. Dalam pada itu, kesan EBN ke atas metabolisme kolesterol masih belum dikaji dengan terperinci sehingga kini. Organ hati memainkan peranan sebagai organ utama di dalam tubuh badan manusia yang melibatkan metabolisme kolesterol terutamanya pada hati. Justeru, sel HepG2 iaitu sel hepatosit hati dipilih sebagai model kajian rintis terhadap peranan EBN pada organ hati secara in-vitro. Menerusi kajian yang telah dijalankan terhadap ekstrak EBN (EBNE) menemukan bahawa, walaupun dos tersebut paling tinggi (1.5 mg/mL) digunakan, namun kelangsungan sel HepG2 hidup adalah sebanyak 71%. Pada masa yang sama, EBNE telah meningkatkan pengekspresan gen LDL-R dengan ketara melalui perencatan gen HMGCR pada EBNE berkepekatan tertinggi. Manakala, ACAT2 turut jelas sekali meningkat dalam memainkan peranan ia membolehkan penyimpanan kolesterol eksogenus di dalam sel. Analisis ekspresi gen-gen ini berkait dengan taburan imunopendarfluor LDL-R dan LD yang tinggi berbanding dengan kumpulan rawatan seumpamanya. Rentetan kajian pengekspresan gen dan pewarnaan imunopendarfluor, didapati kepekatan kolesterol intrahepatosel telah meningkat pada dos EBNE yang tertinggi nyata sekali. EBNE telah menambahbaik metabolisme kolesterol di dalam sel HepG2 melalui perencatan gen HMGCR serta meningkatkan pengekspresan gen LDL-R pada dos tertinggi. Lantaran itu, kajian ini memberikan pemahaman mengenai kesan EBNE dalam menambahbaikkan metabolisme kolesterol di dalam tubuh badan manusia.

Kata kunci: 3-hidroksi-3-metilglutharaldehid CoA reduktase (HMGCR); metabolisme kolesterol; sarang burung walet (EBN); HepG2; reseptor lipoprotein berketumpatan rendah (LDL-R)

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*Corresponding author; email: mokrish@upm.edu.my