• Journal of Veterinary Science
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• 제23권5호
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• pp.74.1-74.16
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• 2022

Background: Previous studies have presented evidence to support the significant association between red meat intake and colon cancer, suggesting that heme iron plays a key role in colon carcinogenesis. Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, exhibits anti-oxidative and anti-cancer effects. However, the effect of EGCG on red meat-associated colon carcinogenesis is not well understood. Objectives: We aimed to investigate the regulatory effects of hemin and EGCG on colon carcinogenesis and the underlying mechanism of action. Methods: Hemin and EGCG were treated in Caco2 cells to perform the water-soluble tetrazolium salt-1 assay, lactate dehydrogenase release assay, reactive oxygen species (ROS) detection assay, real-time quantitative polymerase chain reaction and western blot. We investigated the regulatory effects of hemin and EGCG on an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colon carcinogenesis mouse model. Results: In Caco2 cells, hemin increased cell proliferation and the expression of cell cycle regulatory proteins, and ROS levels. EGCG suppressed hemin-induced cell proliferation and cell cycle regulatory protein expression as well as mitochondrial ROS accumulation. Hemin increased nuclear factor erythroid-2-related factor 2 (Nrf2) expression, but decreased Keap1 expression. EGCG enhanced hemin-induced Nrf2 and antioxidant gene expression. Nrf2 inhibitor reversed EGCG reduced cell proliferation and cell cycle regulatory protein expression. In AOM/DSS mice, hemin treatment induced hyperplastic changes in colon tissues, inhibited by EGCG supplementation. EGCG reduced the hemin-induced numbers of total aberrant crypts and malondialdehyde concentration in the AOM/DSS model. Conclusions: We demonstrated that EGCG reduced hemin-induced proliferation and colon carcinogenesis through Nrf2-inhibited mitochondrial ROS accumulation.

• Journal of Veterinary Science
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• 제24권4호
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• pp.52.1-52.13
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• 2023

Background: Mesenchymal stem cells (MSCs) have been investigated as therapeutic agents for inflammatory bowel disease (IBD). Stimulation of MSCs with pro-inflammatory cytokines is an approach to enhance their immunomodulatory effects. However, further investigation is required to support their application in immune-mediated disorders and companion animals. Objectives: This study aimed to assess the therapeutic effect of tumor necrosis factor (TNF)-α-stimulated feline adipose tissue-derived MSCs (fAT-MSCs) in a dextran sulfate sodium (DSS)-induced colitis mouse model. Methods: Colitis mice was made by drinking water with 3% DSS and fAT-MSCs were injected intraperitoneally. Colons were collected on day 10. The severity of the disease was evaluated and compared. Raw 264.7 cells were cultured with the conditioned medium to determine the mechanism, using quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Results: TNF-α-stimulated fAT-MSCs more improved severity of DSS-induced colitis in disease activity, colon length, histologic score, and inflammatory cytokine. In sectionized colon tissues, the group comprising TNF-α-stimulated fAT-MSCs had higher proportion of CD11b⁺CD206⁺ macrophages than in the other groups. In vitro, TNF-α-stimulation increased cyclooxygenase-2 (COX-2) expression and prostaglandin E₂ (PGE₂) secretion from fAT-MSCs. The conditioned medium from TNF-α-stimulated fAT-MSCs enhanced the expression of interleukin-10 and arginase-1 in LPS-activated Raw 264.7 cells. Conclusions: These results represent that TNF-α-stimulated fat-mscs ameliorate the inflamed colon more effectively. Furthermore, we demonstrated that the effectiveness was interlinked with the COX-2/PGE₂ pathway.

• 생명과학회지
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• 제24권12호
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• pp.1339-1344
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• 2014

염증성 장질환은 점막의 만성적 궤양과 염증을 동반하는 면역질환으로 알려져 있으며, 특히 TNF${\alpha}$와 같은 염증성 사이토카인은 주요한 생물학적 치료의 표적으로 이용되고 있다. 염증성 사이토카인의 유전자발현에서 전사물의 안정화는 매우 중요한 조절과정이며, 특히 본 연구에서는 이 안정화에 핵심적인 단백질인 HuR의 발현과 조직 분포에 대하여 동물모델과 환자의 조직에서 분석하였다. DSS를 처리함으로 유도되는 장염증 동물 모델에서 HuR 단백질의 발현량이 높았음을 확인했고, 점막의 상피조직 및 선조직 상피세포에서 상대적인 발현이 증대되었다. 또한 단백질의 활성측면에서 세포질로 이동된 HuR 단백질의 양도 상대적으로 증가하였다. 공간분포적으로 보면 DSS에 의한 화학적 점막자극에 의하여 초기에는 villi 하부에서의 발현정도가 상대적으로 villus 말단에 비하여 높게 유지되었다. 크론병 환자의 생검을 통하여 정상부위와 병변부위에서 HuR 단백질을 비교분석 하였다. 크론병 환자들의 병변에서는 지속적으로 HuR의 발현이 증대되어 있음을 확인했으며, 동물조직과 유사하게 병변부위의 장관상피세포 및 선 상피에서 주로 발현양이 높았다. 이러한 결과는 염증성 장질환에서의 HuR 단백질이 초기 염증성 인자의 발현에 중요한 역할이 예상되며, 구체적인 분자기전의 규명도 향후 기대된다. 이를 근간으로 하여 염증성 장질환의 진단과 치료의 표적개발에서 유용하게 응용하고자 한다.