Pig Preadipocytes Research Articles

MiR-10a-5p Regulates the Proliferation and Differentiation of Porcine Preadipocytes Targeting the KLF11 Gene.

In the swine industry, meat quality, color, and texture are influenced by the excessive differentiation of fat cells. miRNAs have emerged as integral regulators of adipose development. This study delves into the influence of miR-10a-5b on the proliferation and differentiation of pig preadipocytes. Our findings reveal that miR-10a-5b is prevalent across various tissues. It hinders preadipocyte proliferation, amplifies the expression of adipogenic genes, promotes lipid accumulation, and, as a result, advances preadipocyte differentiation. We predict that KLF11 is the target gene of miRNA. A dual-fluorescence reporter assay was conducted to validate the binding sites of miR-10a-5b on the 3'UTR of the KLF11 mRNA. Results showed that miR-10a-5b targeted KLF11 3'UTR and reduced the fluorescence activity of the dual-fluorescent reporter vector. Our research also indicates that miR-10a-5b targets and downregulates the expression of both mRNA and the protein levels of KLF11. During the differentiation of the preadipocytes, KLF11 inhibited adipose differentiation and was able to suppress the promotion of adipose differentiation by miR-10a-5b. This underscores miR-10a-5b's potential as a significant regulator of preadipocyte behavior by modulating KLF11 expression, offering insights into the role of functional miRNAs in fat deposition.

MiR-34a regulates adipogenesis in porcine intramuscular adipocytes by targeting ACSL4

BackgroundIntramuscular fat (IMF) content is an important factor in porcine meat quality. Previously, we showed that miR-34a was less abundant in liver tissue from pigs with higher backfat thickness, compared to pigs with lower backfat thickness. The purpose of this present study was to explore the role of miR-34a in adipogenesis.ResultBioinformatics analysis identified Acyl-CoA synthetase long chain family member 4 (ACSL4) as a putative target of miR-34a. Using a luciferase reporter assay, we verified that miR-34a binds the ACSL4 mRNA at the 3’UTR. To examine the role of the miR-34a-ACSL4 interaction in IMF deposition in the pig, mRNA and protein expression of the ACSL4 gene was measured in primary intramuscular preadipocytes transfected with miR-34a mimic and inhibitor. Our results showed that ACSL4 is expressed throughout the entire differentiation process in pig preadipocytes, similar to the lipogenesis-associated genes PPARγ and aP2. Transfection with miR-34a mimic reduced lipid droplet formation during adipogenesis, while miR-34a inhibitor increased lipid droplet accumulation. Transfection with miR-34a mimic also reduced the mRNA and protein expression of ACSL4 and lipogenesis genes, including PPARγ, aP2, and SREBP-1C, but increased the expression of steatolysis genes such as ATGL and Sirt1. In contrast, the miR-34a inhibitor had the opposite effect on gene expression. Further, knockdown of ACSL4 decreased lipid droplet accumulation.ConclusionsOur results support the hypothesis that miR-34a regulates intramuscular fat deposition in porcine adipocytes by targeting ACSL4.

MicroRNA-128 is involved in dexamethasone-induced lipid accumulation via repressing SIRT1 expression in cultured pig preadipocytes

In this study, pig preadipocytes were firstly treated with 10−6 M DEX for 48 h to explore the role of dexamethasone (DEX, a chemically synthesized long-acting glucocorticoid) on lipid accumulation. Then, miRNA scrambled control (miR-SC), miR-128 overexpression plasmid and miR-128 inhibitor were respectively transfected into pig preadipocytes at 24 h before DEX treatment for 48 h (miR-SC-DEX, miR-128-DEX and miR-128-inhibitor-DEX) to illustrate the regulatory role of miR-128 on DEX-induced lipid accumulation. Compared with control preadipocytes, 10-6 M Dex significantly increased triglyceride (TG) level, whereas the cell proliferation did not change. Moreover, 10-6 M Dex obviously decreased sirtuin 1 (SIRT1) and its related lipolysis genes adipose triglyceride lipase (ATGL) and hormone sensitive lipase (HSL) mRNA expression and enzyme activity, while significantly increased expression of adipogenesis genes peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer binding protein-α (C/EBP-α) and fatty acid synthase (FAS). In addition, 10-6 M DEX significantly upregulated miR-128 expression, which was confirmed to directly target SIRT1 by bioinformatics analysis and dual-luciferase reporter assay. Gain- and loss-of-function study also showed that when compared with miR-SC-DEX cells, miR-128-DEX cells showed significantly reduced SIRT1 expression and increased TG level, as well as elevated cellular levels of PPAR-γ, C/EBP-α and FAS and suppressed ATGL and HSL expression and enzyme activity. In contrast, miR-128-inhibitor-DEX cells precisely presented the opposite results. Collectively, these results indicate that miR-128 plays a role in the pathogenesis of glucocorticoid-related abnormal lipid accumulation via repressing SIRT1 expression, consequently, miR-128 inhibition may represent a novel potential therapeutic target in preventing DEX-induced abnormal lipid accumulation.

Thymine DNA Glycosylase Gene Knockdown Can Affect the Differentiation of Pig Preadipocytes

Aims: To study the effect of thymine DNA glycosylase (TDG) gene knockdown on the differentiation of pig preadipocytes. Methods: Preadipocytes were obtained from subcutaneous adipose tissue from the neck of 1- to 7-day-old pigs. The TDG gene was knocked down using siRNA, and cell differentiation was induced. The mRNA expression level was measured using fluorescence quantitative PCR, and the protein expression level was determined using Western blot analysis. The DNA methylation levels in promoter regions of differentiation-related genes were also evaluated. Results: TDG gene knockdown decreased the mRNA expression levels of the peroxisome proliferator-activated receptorγ (PPARγ) and Fatty acid binding proteins 4(FABP4 Also known as aP2) genes (P<0.01), while the mRNA expression level of the CCAAT/enhancer binding protein alpha(C/EBPα) gene did not change significantly (P>0.05). In addition, after induced differentiation, the lipid droplet production significantly decreased, and the percentages of methylation in the promoter regions of C/EBPα, PPARγ, and aP2 genes were 0.9%, 80%, and 76%, respectively. In contrast, the percentages of methylation in the negative control groups were 0.5%, 67.5%, and 58%, respectively. Conclusion: TDG gene knockdown could inhibit the differentiation of pig preadipocytes and affect the DNA methylation levels of some transcription factors.

Ramie Leaf Extracts Suppresses Adipogenic Differentiation in 3T3-L1 Cells and Pig Preadipocytes.

The present study was carried out to evaluate the anti-obesity effect of different concentrations of extracts of hot air-dried ramie leaf (HR) and freeze-dried ramie leaf (FR) in 3T3-L1 cells and pig preadipocytes. To analyze the effect on cell proliferation, cells were treated with 25 μg/mL or 100 μg/mL HR or FR extract for 2 days. Cell differentiation was evaluated by measuring glycerol-3-phosphate dehydrogenase and lipoprotein lipase (LPL) activities and intracellular triglyceride content. Treatment with either HR or FR extracts inhibited the proliferation of 3T3-L1 cells and pig preadipocytes in a dose-dependent manner. HR extract treatment inhibited the differentiation of both cell types more effectively than FR treatment. The extent of triglyceride accumulation decreased significantly in both cells following either HR or FR treatment. Furthermore, LPL activity significantly decreased after treatment with HR or FR extract. These results indicated that HR and FR extracts may inhibit proliferation and differentiation of 3T3-L1 cells and pig preadipocytes. Further studies are needed to explore the anti-obesity effect of HR and FR extracts.

The proliferation and differentiation of primary pig preadipocytes is suppressed when cultures are incubated at 37°Celsius compared to euthermic conditions in pigs

Given similarities in metabolic parameters and cardiovascular physiology, the pig is well positioned as a biomedical model for metabolic disease and obesity in humans. Better understanding molecular mechanisms governing porcine adipocyte hyperplasia may provide insight into the regulation of adipose tissue development that is useful both when considering the pig as a commodity and when extrapolating porcine data to human disease. Primary cultures of pig stromal-vascular cells have served as a useful tool for investigating factors that regulate preadipocyte proliferation and differentiation. However, such cultures have generally been maintained at 37°C in vitro despite euthermia being 39°C in pigs. To address potential concerns about the physiological relevance of culturing primary pig preadipocytes under what would be hypothermic conditions in vivo, the objective of this study was to investigate the effect of culture temperature on the proliferation and differentiation of pig preadipocytes in primary culture. Culturing primary preadipocytes at 37 rather than 39°C decreases their proliferation rates based upon cleavage of the tetrazolium salt, MTT (P < 0.001), reduction of resazurin (P < 0.001), and daily cell counts (P < 0.001). Likewise, culturing primary porcine preadipocytes at 37°C suppressed their adipogenic potential based upon monitoring adipogenesis morphologically, biochemically, and via the expression of mRNA encoding adipogenic marker genes. Collectively, these data indicate the proliferation and differentiation of primary pig preadipocytes is suppressed when cultures are incubated at 37°C compared to normal body temperature of pigs. This may confound investigation of factors that impact adipocyte hyperplasia in the pig.

콜라비가 돼지 지방전구세포와3T3-L1cell의 증식과 분화에 미치는 영향

본 연구는 콜라비가 돼지 지방전구세포와 <TEX>$_3T_3-L_1$</TEX> 세포의 증식과 분화에 미치는 영향을 구명하기 위해 수행하였다. 돼지 지방전구세포는 신생자돈의 등지방에서 분리했다. 세포를 접종한 1일 후에 세척했고(day 0), 세포증식에 미치는 영향을 구명하기 위해서 2일 동안(day 0~day 2) 25 ng/ml과 100 ng/ml의 콜라비 알코올 추출물(과피와 과육)를 처리했다. 세포분화를 구명하기 위해서는 DMEM/F- 12 배지에 6일 동안(day 0~day 6) 배양하고 배양초기 2일 동안(day 0~day 2) 콜라비를 처리하고 day 6에 세포 분화를 측정했다. 콜라비 과피 25 ng/ml와 100 ng/ml은 돼지 지방전구세포의 증식을 각각 4.59%, 17.7% 억제했고, 콜라비 과육은 각각 11.4%, 19.2% 억제했다. 반면 돼지 지방전구세포의 분화는 억제하지 않았다. 콜라비가 <TEX>$_3T_3-L_1$</TEX> cell의 증식과 분화에 미치는 작용을 구명하기 위해, 돼지 지방전구세포처럼, 세포 배양초기 2일간 콜라비를 처리했는데 콜라비 과피와 과육 둘 다 세포의 증식과 분화에 영향을 미치지 않았다. 본 연구의 결과를 요약하면, 콜라비는 돼지 지방전구세포의 증식을 억제했으나 분화는 억제하지 않았고, 한편 <TEX>$_3T_3-L_1$</TEX> cell의 증식과 분화 모두 영향을 미치지 않았다. The current study was carried out to determine the effects of Kohlrabi (Brassica oleracea var. gongylodes) on proliferation and differentiation of pig preadipocytes and <TEX>$_3T_3-L_1$</TEX> cells. Pig preadipocytes were isolated from the backfat of the new-born pigs. Twenty-four hours after seeding, the cells were washed with DMEM/F-12 (designated day 0). To measure the cell proliferation, the cells were treated with 25 ng/ml and 100 ng/ml ethanol extracts of Kohlrabi (peel and flesh) for two days (day 0 ~ 2). To measure differentiation, the cells were treated with Kohlrabi for two days (day 0 ~ 2) and cell differentiation was measured on day 6. Twenty-five ng/ml and 100 ng/ml of Kohlrabi peel decreased proliferation of pig preadipocytes by 4.59% and 17.7%, respectively, compared with the control and Kohlrabi flesh by 11.4% and 19.2%, respectively. However, Kohlrabi did not inhibit cell differentiation. To measure the effects of Kohlrabi on proliferation and differentiation of <TEX>$_3T_3-L_1$</TEX> cells, the cells were treated with Kohlrabi for two days in culture, like pig preadipocytes. Kohlrabi (both peel and flesh) did not show any effects on cell proliferation and differentiation. In summary, the results of the current study showed that Kohlrabi decreased proliferation of pig preadipocytes, but no inhibitory effects on differentiation of the cells. Kohlrabi had no effects on proliferation and differentiation of <TEX>$_3T_3-L_1$</TEX> cells.

Effect of Retinoic Acid on Proliferation and Differentiation of Preadipocytes from Male and Female Pigs

The current study was undertaken to determine the effect of retinoic acid (RA) on proliferation and differentiation of preadipocytes from male and female pigs. The preadipocytes were isolated from new-born male and female pigs by collagenase digestion and washed three times one day after seeding (designated as day 0 of culture). RA was included in the media at various concentratives from day 0 to 2. The cell number was measured on day 2 with hematocytometer after trypsin digestion. Cell differentiation was determined on day 6 by measuring glycerol-3-phosphate dehydrogenase activity. RA (0.1, 1 and 10 uM) showed no effect on proliferation of preadipocytes from both male and female pigs. However, RA significantly decreased differentiation of pig preadipocytes. Degree of differentiation with 0.1 uM, 1 uM and 10 uM of RA treatment was 80%, 41% and 29% respectively, compared with control. Similar inhibitory effect was found in the female pigs; 77%, 28% and 16% respectively. It is interesting that RA treated on cell proliferation stage had no effect on proliferation but had a strong inhibitory effect on differentiation which is happening in the late stage of cell culture.

한국 약용식물 추출물이 In vitro 돼지 지방조직의 지방합성과 지방전구세포의 분화에 영향을 미친다

In vivo 실험에 의해서 지방축적을 억제할 수 있는 물질을 찾아내는 것은 시간과 비용이 많이 든다. 본 연구는 돼지 지방조직을 이용한 in vitro system을 이용해서 한국의 약용식물 중에서 지방축적 억제 작용을 가지는 것을 조사하고자 수행하였다. 총 183종의 약용식물을 이용하여 이들이 돼지 지방조직의 지방합성과 지방전구세포의 분화에 미치는 작용을 조사하였다. 에탄올 추출물은 72종, 물 추출물은 111종, 이 중에서 65종은 물과 에탄올 모두 이용해서 추출하였다. 돼지 지방조직의 지방합성은 13종류의 약용식물이 영향을 미쳤는데, 그 중 11종은 대조구에 비하여 지방합성을 40% 이상 억제하였고, 4종은 지방합성을 70% 이상 억제하였다. 가장 강력한 지방합성 억제작용을 나타낸 것은 붓꽃과와 고삼(에탄올 추출) 그리고 좁쌀풀(물과 에탄올 추출)이었다. 그러나 소목과 황백은 지방합성을 촉진하였다. 돼지 지방전구세포의 분화에 미치는 결과는 총 28종의 약용식물이 돼지 지방전구세포의 분화에 영향을 미쳤는데, 이 중 16종의 약용식물은 증가시켰고, 12종은 억제시켰다. 목단피와 강활(에탄올 추출) 그리고 당귀, 목향 및 신이(물 추출)는 지방세포의 분화를 두 배 정도 증가시켰다. 10종의 약용식물 즉 감초, 형개 및 구월나무(에탄올 추출) 그리고 비름과, 천문동, 백출, 유자나무, 향부자, 구엽초 및 목단피(물 추출)은 지방세포의 분화를 35% 이상 억제시켰다. 구월나무(에탄올 추출)만이 지방합성뿐만 아니라 세포분화도 억제하였다. 본 연구 결과는 약용식물로부터 가축과 사람의 지방축적 억제효능 후보물질을 발굴하기 위한 기초자료로 활용할 수 있을 것으로 여겨진다. Identification of natural compounds that can prevent the development of obesity in vivo is time consuming and expensive. We have used in vitro systems derived from pig adipose tissue to screen simple aqueous or ethanolic extracts of Korean medicinal herbs (KMH) for their anti-adipogenic potential. A total of 183 extracts were tested for their actions in lipogenesis of pig adipose tissue and differentiation of pig preadipocytes. Ethanol extracts were prepared from 72 and aqueous extracts were prepared from 111 medicinal herbs. Both an ethanolic and an aqueous extract were prepared from 65 of these. Thirteen extracts substantially altered rates of lipogenesis in vitro. The effects of KMH on lipogenesis of pig adipose tissue are as follows. Elevens reduced lipogenesis to rates that were more than 40% lower than control and four of these reduced rates of lipogenesis by more than 70%. The most potent anti-lipogenic extracts were those obtained in ethanol from Iridaceae and from Sophora flavescens AIT as well as both the aqueous and ethanolic extracts from Lysimachia vulgaris L. Two extracts, those prepared in water from Caesalpiniae lignum and from Phellodendri cortex, were found to promote rates of lipogenesis in vitro. The effects of KMH on differentiation of pig preadoipocytes are as follows. Twentyeight extracts altered the rates of differentiation of cultured porcine preadipocytes. Sixteen increased and twelve reduced the rates of differentiation of preadipocytes. Extracts prepared in ethanol from Moutan radicis cortex and from Ostericum koreanum and those prepared in water from Angelicae gigantis radix, from Inula henenium L and from Magnolia flos doubled the rate of differentiation of cultured porcine preadipocytes. Ten extracts reduced the in vitro rate of differentiation of porcine preadipocytes by more than 35%. These were the ethanolic extracts from Glycyrrizae radix, Nepetae spica and from Polygala myrtifolia and the aqueous extracts from Amaranthaceae, Asparagus cochinchinesis, Atractylodis rhizoma alba, Citrus junos TANAKA, Cyperus rotundus, Epimedium grandiflorum and from Moutan radicis cortex. Only the ethanolic extract from Polygala myrtifolia was able to both reduce lipogenesis in adipose tissue slices and retard differentiation of cultured preadipocytes. The results of our study will provide meaningful information to identify medicinal herbs which would reduce fat deposition in livestocks and humans.

스테로이드 성호르몬이 암, 수 돼지 지방전구세포의 증식과 분화에 미치는 영향

The current study was undertaken to determine the effects of sex steroid hormones (estrogen, testosterone and 19-nortestosterone) on proliferation and differentiation of preadipocytes of female and male pigs. The preadipocytes were isolated from the backfat of new-born female and male pigs by collagenase digestion and cultured in the CO2 incubator. The concentration of 10 7 M and 10-6M sex steroid hormones were treated to the cultured preadipocytes. Regarding the effects on preadipocytes proliferation, high concentration (10 6 M) of all the three hormones increased proliferation of female preadipocytes,and only estrogen and testosterone increased proliferation of male preadipocytes. Regarding the effects on preadipocyte differentiation, all the three hormones increased differentiation of pig preadipocytes, regardless of hormone concentrations and sex of preadipocytes. The degree of stimulation of cell differentiation by sex steroid hormones was greater than that of cell proliferation.

Insulin-like Growth Factors-Ι 과 II 는 서로 다른 수용체－매개 작용기전을 통해 돼지 지방전구세포의 증식과 분화를 촉진한다

본 연구는 insulin-like growth factors(IGFs)가 돼지 지방전구세포의 증식과 분화에 미치는 작용기전을 구명하기 위해서 수행하였다. 지방전구세포는 갓난 암퇘지의 등지방에서 분리하였고, serum-deprived 조건하에서 IGFs와 mutant IGFs를 함유시켜 배양했는데 이 mutant IGFs는 IGF-Ⅰ에 비해 type-1 IGF receptor와 insulin receptor에 대한 친화력이 낮다. 50ng/ml의 IGF-Ⅰ, [Leu60]IGF-I, IGF-Ⅱ 및 [Leu27]IGF-Ⅱ를 배양중인 세포에 4일동안 처리했다. IGF-Ⅰ, [Leu60]IGF-I, IGF-Ⅱ 및 [Leu27]IGF-Ⅱ는 돼지 지방전구세포의 증식을 각각 39%, 8%, 25% 및 2% 촉진했다(증가된 세포수에 의해 측정). 이 사실은 IGF-Ⅰ과 IGF-Ⅱ는 type-1 IGF receptor 또는 insulin receptor에 결합을 통해서 지방세포의 증식 촉진을 가져왔음을 나타낸다. 그리고 IGF-Ⅰ, [Leu60]IGF-I, IGF-Ⅱ 및 [Leu27] IGF-Ⅱ는 지방전구세포의 분화를 50%, 17%, 37% 및 30% 각각 촉진시켰다(세포 분화는 glycerol- phosphate dehydrogenase 활성도에 의해 측정했다). IGF-Ⅰ의 type-1 IGF receptor 또는 insulin receptor에의 친화력이 낮아져서 세포 분화 촉진작용을 감소시킨 것이다. 그러나 [Leu27] IGF-Ⅱ의 분화촉진 작용은 IGF-Ⅱ의 그것에 비해 크게 차이가 나지 않았는데, 이 사실은 IGF-Ⅰ과 IGF-Ⅱ는 서로 다른 수용체－매개 작용기전에 의해 세포분화를 촉진시킴을 나타낸다. 즉 IGF-Ⅱ는 type-1 IGF receptor 또는 insulin receptor가 관여하지 않는 작용을 통해 돼지 지방전구세포의 분화를 촉진시켰다. 이 작용은 IGF-Ⅱ가 type-2 IGF receptor(또는 cation- independent mannose-6 phosphate receptor [CIM6P /IGF2 receptor])에 결합을 통해서 이뤄지는 것으로 여겨진다. 위의 결과는 IGF-Ⅱ가 CIM6P/ IGF2 receptor에의 결합을 통해 동물 지방전구세포의 분화를 촉진시킨다는 것을 밝혀낸 최초의 연구이다. 요약하면 이 본 연구는 IGF-Ⅰ과 IGF-Ⅱ는 서로 다른 세포내 receptor가 관여하는 작용기전을 통해 돼지 지방전구세포의 분화를 촉진함을 보여준다. The current study was undertaken to investigate the mechanism of action of insulin-like growth factors (IGFs) on proliferation and differentiation of pig preadipocytes. The preadipocytes were isolated from the backfat of new-born female pigs and cultured in serum-deprived medium in the presence and absence of recombinant native IGFs or recombinant mutant IGFs that have reduced affinity for binding to both type-1 IGF receptors and insulin receptors. Fifty ng/ml of either IGF-I, [Leu60]IGF-I, IGF-Ⅱ or [Leu27]IGF-Ⅱ were included in the media in which preadipocytes were cultured for 4 days. IGF-I, [Leu60]IGF-I, IGF-Ⅱ and [Leu27]IGF-Ⅱ stimulated proliferation of pig preadipocytes by 39%, 8%, 25% and 2% respectively, as measured by increased numbers of cells. This indicates that both IGF-I and -II promote replication of pig preadipocytes by actions mediated either by type-1 IGF receptor or insulin receptor. IGF-I, [Leu60]IGF-I, IGF-Ⅱ and [Leu27]IGF-Ⅱ stimulated differentiation of pig preadipocytes by 50%, 17%, 37% and 30%, respectively, measured as glycerolphosphate dehydrogenase activity. Reducing the affinity of IGF-I for type-1 IGF receptors or insulin receptors significantly reduced the differentiation response. However, the differentiation response to [Leu27]IGF-II was not significantly different from the response to IGF-II. This shows that IGF-I and IGF-Ⅱ promote cell differentiation by different receptor-mediated mechanisms. IGF-II promotes differentiation of pig preadipocytes by actions that do not involve either type-1 IGF receptors or insulin receptors. These actions therefore appear to be mediated by binding of IGF-II to type-2 IGF receptors(also known as cation-independendent mannose-6-phosphate receptor[CIM6P/IGF2 receptor]). This is the first study to find evidence that IGF-II promotes differentiation of preadipocytes from any animal species by actions mediated by CIM6P/IGF2 receptors. In summary, this study shows that IGF-I and IGF-Ⅱ promote differentiation of pig preadipocytes by mechanisms that involve different cellular receptors.

Retinoic Acid가 돼지 지방전구세포의 분화와 유전자 발현에 미치는 영향

본 연구는 retinoic acid(RA)가 돼지지방전구세포의 분화와 유전자 발현에 미치는 영향을 구명하기 위해서 수행하였다. 지방전구세포는 갓난 돼지의 등지방에서 분리했으며 RA는 배양중인 세포에 4일 동안 처리하였다. 배양중인 세포에서 RNA를 추출한 후 14,688개의 유전자가 부착되어 있는 cDNA microarray와 혼성화 하여 유전자 발현 양상을 분석하였다. 지방전구세포의 분화는 GPDH의 활성도에 의해 측정했다. RA는 돼지지방전구세포의 분화를 78% 억제했다. Retinoic acid 처리에 의해 지질 대사에 관계된 유전자를 포함하여 특히 sphin- gomyelin phosphodiesterase, apolipoprotein R precursor, growth factor receptor-bound protein 14, retinoic receptor RXR gamma의 발현이 증가 되었다. 그리고 세포 성장에 중요 역할을 하는 vascular endothelial growth factor D precursor, growth hormone receptor precursor의 유전자의 발현이 감소되었다. 이러한 결과는, RA가 성장촉진인자 또는 성장호르몬 수용체의 조절을 통해서 돼지 지방전구세포의 분화를 억제함을 나타낸다. The current study was undertaken to determine the effect of retinoic acid(RA) on differentiation and gene expression of pig preadipocytes. The preadipocytes were isolated from the backfat of the new-born pigs. RA was treated to the cultured cells for 4 days and RNA was extracted from the cells. Isolated RNA went through in situ hybridization using the 14,688-gene cDNA microarray chip. Degree of cell differentiation was determined by measuring glycerol 3-phosphate dehydrogenase activity. RA decreased differentiation of pig preadipocytes by 78%. Fourteen genes were significantly up-regulated by RA, including genes known to be involved in lipid metabolism, particulary sphingomyelin phosphodiesterase, apolipoprotein R precursor, growth factor receptor-bound protein 14, retinoic acid receptor RXR gamma. However, the expression of vascular endothelial growth factor D precursor and growth hormone receptor precursor genes playing a central role in cell growth, was greatly decreased. These results suggest that RA inhibits differentiation of pig preadiocytes by regulation of gene expression of the growth factor or growth hormone receptor.

Retinoic Acid가 돼지 지방세포의 분화에 미치는 영향

Retinoic Acid가 돼지 지방세포의 분화에 미치는 영향

Developmental, Hormonal, and Nutritional Regulation of Porcine Adipose Triglyceride Lipase (ATGL)

Adipose triglyceride lipase (ATGL) is a newly identified lipase. We report for the first time the porcine ATGL sequence and characterize ATGL gene and protein expression in vitro and in vivo. Adult pig tissue expresses ATGL at high levels in the white adipose and muscle tissue relative to other tested tissues. We show that within the white adipose tissue ATGL is expressed at higher levels in the adipocyte than in the stromal-vascular fraction. Additionally, ATGL expression increases dramatically in the subcutaneous adipose during adipose development and maturation, as well as during in vitro adipogenesis. Peroxisome proliferator-activated receptor gamma transcript levels increased concomitant with ATGL gene expression, suggesting a possible role in the regulation of ATGL by adipogenic regulators. In vitro treatment of differentiated primary pig preadipocytes with insulin and forskolin decreased ATGL gene expression in a dose-dependent manner, suggesting ATGL transcript levels are hormone sensitive. In vivo experimentation showed that calorie-restriction in gilts resulted in increased ATGL mRNA and protein levels in subcutaneous and peri-renal fat tissues. Our data demonstrate that ATGL expression reacts to hormonal stimuli and plays a role in catecholamine-induced lipolysis in porcine adipose tissue.

스테로이드 성호르몬이 돼지 지방전구세포의 분화에 미치는 영향

본 연구는 스테로이드 성호르몬 즉 에스트로겐, 테스토스테론 및 노르테스토스테론이 돼지 지방전구세포의 분화와 증식에 미치는 영향을 구명하기 위해서 수행하였다. 지방전구세포는 갓난 암퇘지의 등지방조직을 떼어내어 coll- agenase를 처리해서 분리해서 배양했다. 세포 배양중에 10－8M과 10－7M의 스테로이드 성호르몬을 처리했다. 세포배양 전기에 스테로이드 성호르몬을 처리했을 때 지방전구세포의 분화나 증식에 아무런 영향을 미치지 않았고, 세포배양 후기에 처리했을 때는 테스토스테론과 노르테스토스테론이 세포분화를 촉진시켰다. The current study was undertaken to determine the effects of sex steroid hormones(estrogen, testosterone and 19-nortestosterone) on differentiation and proliferation of pig preadipocytes. The preadipocytes were isolated from the backfat of new-born female pigs by collagenase digestion. 10－8M and 10－7M sex steroid hormones were treated to the cultured preadipocytes. Sex steroid hormones treated during the early stage of cell growth did not affect differentiation and proliferation of preadipocytes. However, testosterone and 19- nortestosterone treated during the late stage of cell growth stimulated differentiation of pig preadipocytes.

Modulation of Sirt1 by resveratrol and nicotinamide alters proliferation and differentiation of pig preadipocytes

Sirt1, a NAD(+)-dependent histone deacetylase, may regulate senescence, metabolism, and apoptosis. In this study, primary pig preadipocytes were cultured in DMEM/F12 medium containing 10% fetal bovine serum (FBS) with or without reagents affecting Sirt1 activity. The adipocyte differentiation process was visualized by light microscopy after Oil red O staining. Proliferation and differentiation of preadipocytes was measured using methylthiazolyldiphenyl-tetrazolium bromide (MTT) and Oil red O extraction. Expression of Sirt1, FoxO1, and adipocyte specific genes was detected with semi-quantitive RT-PCR. The results showed that Sirt1 mRNA was widely expressed in various pig tissues from different developmental stages. Sirt1 mRNA was expressed throughout the entire differentiation process of pig preadipocytes. Resveratrol significantly increased Sirt1 mRNA expression, but decreased the expression of FoxO1 and adipocyte marker gene PPARgamma2. Resveratrol significantly inhibited pig preadipocyte proliferation and differentiation. Nicotinamide decreased the expression of Sirt1 mRNA, but increased the expression of FoxO1 and adipocyte specific genes. Nicotinamide greatly stimulated the proliferation and differentiation of pig preadipocytes. In conclusion, these results indicate that Sirt1 may modulate the proliferation and differentiation of pig preadipocytes. Sirt1 may down-regulate pig preadipocytes proliferation and differentiation through repression of adipocyte genes or FoxO1.

Conjugated Linoleic Acid(CLA)가 돼지 지방세포와 근육세포의 증식과 분화에 미치는 영향

ABSTRACT The current study was undertaken to determine the effect of conjugated linoleic acid (CLA) isomers, cis-9, cis-11 (c9c11), cis-9, trans-11 (c9t11), trans-9, trans-11 (t9t11), trans-10, cis-12 (t10c12) on differentiation of pig preadipocytes and myogenic satellite cells during culture. Cells were isolated from new born pigs. The t10c12 isomer decreased differentiation of pig preadipocytes (92%), but not that of myogenic cells. The t9t11 isomer decreased differentiation of preadipocytes (14%) and increased that of myogenic cells (26%). No other CLA isomers affected differentiation of preadipocytes or myogenic cells. The effects of CLA on proliferation of preadipocytes and myogenic cells were small, compared to the effects on differentiation. These results suggest that CLA isomers have different effects on differentiaton of pig preadipocytes and myogenic cells. ( Key words : CLA, Pig, Preadipocyte, Myogenic satellite cells, Differentiation) . 서 론 Conjugated linoleic acid(CLA)는 linoleic acid (LA)의 이성체로서, LA는 이중결합이 9번과 12번 탄소에 있고, 모두 cis형인데, CLA는 이중결합이 9번과 11번 또는 10번과 12번 등의 탄소에 있고, cis형 뿐만 아니라 trans형도 있다. CLA의 항암작용, 항동맥경화작용, 항비만작용 등이 알려졌기에(Pariza 등 2000; Brown과 Mclntosh, 2003; Azain, 2004), 최근에 와서 건강보조제로서 주목을 받게 되었다. CLA의 가축의 생산과 관련된 작용으로는 지방축적 억제작용이 중요시되고 있는데 돼지에게 CLA를 급여한 결과 지방축적이 억제되었음이 보고되었다(Dugan등, 1997; Ostrowska 등, 2003; Dugan 등, 2004). 이에 대한 작용 구명과 관련해서 CLA의 지방전구세포의 분화에 미치는 작용에 대한 연구가 수행되어 왔다(Brodie 등, 1999; Evans 등, 2001; Kang 등, 2003). Brown 등(2003)은 trans-10, cis-12 CLA가 사람 지방전구세포의 분화를 억제했다고 보고했는데 McNeel 과 Mersmann(2003) 돼지 지방전구세포를 이용한 실험에서 CLA가

Isomer-specific regulation of differentiating pig preadipocytes by conjugated linoleic acids1

Conjugated linoleic acids are a group of geometric and positional isomers of linoleic acid that decrease body fat in growing animals by a poorly understood mechanism. The objective of this study was to investigate the isomer-specific effect of CLA on the proliferation and differentiation of pig preadipocytes in primary culture. The effect of CLA on preadipocyte proliferation was determined using cleavage of the tetrazolium salt, WST-1, as a marker for proliferation. Preadipocyte number was decreased in a dose-dependent fashion by trans-12,cis-10 CLA (P < 0.05). No other fatty acid affected preadipocyte number. Differentiation was monitored on d 10 after induction morphologically, enzymatically, and by measuring the mRNA abundance of key adipogenic transcription factors. Both a crude CLA preparation containing a mixture of CLA isomers (CLA-mix) and the pure trans-10,cis-12 CLA isomer inhibited glycerol-3-phosphate dehydrogenase (GPDH) activity in a dose-dependent fashion, with trans-10,cis-12 CLA being more potent (P < 0.01) than the CLA-mix. Cis-9,trans-11 CLA failed to decrease GPDH activity; however, increasing concentrations of cis-9,trans-11 CLA tended to blunt the inhibitory effect of trans-10,cis-12 CLA on GPDH activity (P < 0.09), suggesting that cis-9,trans-11 CLA may antagonize the action of trans-10,cis-12 CLA in porcine adipocytes. Finally, the isomer-specific effect of CLA on adipogenic transcription factor gene expression was investigated. Trans-10,cis-12 CLA decreased expression of peroxisome proliferator-activated receptor gamma (PPAR gamma; P < 0.01) and sterol regulatory element-binding protein-1c (SREBP-1c; P < 0.05) mRNA, while failing to alter the expression of CCAAT/enhancer binding protein alpha (C/EBPalpha) mRNA. Interestingly, both the CLA-mix and the trans-10,cis-12 CLA isomer increased the mRNA abundance of chicken ovalbumin upstream promoter transcription factor 1 (COUP-TF; P < 0.002). No other fatty acid affected COUP-TF mRNA levels. Collectively these data support the concept that CLA decreases fat accretion in pigs, in part by inhibiting preadipocyte proliferation and differentiation, with trans-10,cis-12 CLA being an active isomer eliciting these effects. Furthermore, trans-10,cis-12 CLA inhibits porcine preadipocyte differentiation by a mechanism that involves the down-regulation of PPARgamma and SREBP-1c mRNA. This mechanism is independent of changes in C/EBPalpha mRNA abundance and may involve COUP-TF.

Regulation of differentiating pig preadipocytes by retinoic acid

All-trans retinoic acid (ATRA) potently inhibits the differentiation of porcine preadipocytes in primary culture; however, the mechanism by which ATRA exerts this effect in pigs is poorly understood. The objective of this study was to use retinoid receptor-specific ligands to investigate the mechanism underlying the antiadipogenic action of retinoids in cultured pig preadipocytes by identifying the retinoid receptor mediating this action and examining the effect of retinoids on the expression of key adipogenic transcription factors. Stromal-vascular cells were harvested from porcine adipose tissue and cultured in serum-free medium. Glycerol-3-phoshphate dehydrogenase (GPDH) activity, a late marker of preadipocyte differentiation, was decreased (P < 0.01) by the addition of 0 to 10 microM of either ATRA, a nonspecific agonist for both the retinoic acid receptor (RAR) and the retinoid X receptor (RXR) or the selective RAR agonist, 4-(E-2-[5,6,7,8-tet-rahydro-5,5,8,8-tetramethyl-2-naphthalenyl]-1-propenyl) benzoic acid (TTNPB). Addition of increasing amounts of Ro-61, a RAR-specific antagonist (0 to 10 microM) prevented ATRA and TTNBP from decreasing GPDH activity. Addition of methoprene acid, an RXR-specific agonist, increased (P < 0.01) GPDH activity. Preadipocytes were then continuously treated with 10 nM of TTNPB in the presence or absence of 1 microM Ro-61, and mRNA was isolated on d 2 and 8. Addition of TTNPB decreased (P < 0.001) the expression of peroxisome proliferator-activated receptor gamma (PPARgamma), sterol regulatory element-binding protein-1c (SREBP-1c), retinoid X receptor alpha (RXRalpha), and adipocyte fatty acid binding protein (aP2) mRNA transcripts, whereas these effects were prevented by the presence of Ro-61. Interestingly, TTNBP increased (P < 0.001) the mRNA abundance of the orphan nuclear receptor chicken ovalbumin upstream promoter-transcription factor 1 (COUP-TF1), whereas Ro-61 prevented this increase. These changes were independent of alterations in the mRNA abundances of the retinoic acid receptor alpha, and CCAAT/enhancer binding protein alpha and beta (C/EBPbeta; C/EBPalpha) genes. These results indicate that retinoic acid inhibits porcine preadipocyte differentiation by a mechanism that involves activation of the RAR and downregulation of PPARgamma, RXRalpha, and SREBP-1C mRNA. This mechanism is independent of changes in C/EBPbeta and C/EBPalpha mRNA abundance and may involve COUP-TF.

Insulin and hydrocortisone, but not triiodothyronine, are required for the differentiation of pig preadipocytes in primary culture.

The objective of this study was to establish optimal conditions for the primary culture of pig preadipocytes. We cultured pig preadipocytes for 10 d and studied the effects of insulin, hydrocortisone, and triiodothyronine (T3) added to serum-free basal medium on differentiation and gene expression of lipoprotein lipase an early marker, and adipsin, a late marker of preadipocyte differentiation. Insulin alone and hydrocortisone alone stimulated a low level of cell differentiation, as indicated by an increase in glycerol-3-phosphate dehydrogenase activity. When added together, insulin and hydrocortisone had a synergistic effect on cell differentiation. When combined with insulin or hydrocortisone, T3 had no effect on cell differentiation, indicating that T3 is not required in porcine preadipocyte culture. Gene expression studies also showed that removal of insulin or hydrocortisone from complete serum-free medium reduced both early and late marker mRNA. As expected, removal of T3 had no effect on the gene expression of early and late marker mRNA. We conclude that insulin and hydrocortisone, but not T3, are required for the differentiation of pig preadipocytes in primary culture.