Effect of Inhibiting PPARγ Expression on Osteogenic Differentiation of BMSCs
-
摘要:
目的 探究抑制过氧化物酶增殖物激活受体γ(peroxisome proliferator-activated receptor γ,PPARγ)表达对BMSCs成骨分化的影响,为原发性骨质疏松症(primary psteoporosis ,POP)的治疗提供理论基础。 方法 将骨密度正常患者提取的BMSCs分为正常对照组(CON组),POP患者提取的BMSCs分为原发性骨质疏松组(POP组),取POP组细胞加入PPARγ抑制剂,分为抑制剂组(INR组),经成骨诱导分化后,检测各组细胞中骨桥蛋白(osteopontin, OPN)、骨钙素(osteocalcin,OCN)、Osterix、Runt相关转录因子2 (runt-related transcription factor 2 ,Runx2)的表达情况;碱性磷酸酶(alkaline phosphatase,ALP)染色观察各组BMSCs成骨分化情况。 结果 POP组ALP阳性细胞数低于CON组和INR组(P < 0.05);与CON组相比,POP组中OCN、OPN、Osterix、Runx2表达量降低,差异具有统计学意义(P < 0.05);与POP组相比,INR组中OCN、OPN、Osterix、Runx2表达量升高,差异具有统计学意义(P < 0.05)。 结论 抑制PPARγ表达后,BMSCs成骨分化特异性基因(ALP、OCN、OPN、Osterix、Runx2)表达增加。 Abstract:Objective To investigate the impact of inhibiting peroxisome proliferator-activated receptor γ (PPARγ) expression on osteogenic differentiation of BMSCs, so as to provide a theoretical basis for the treatment of primary osteoporosis (POP). Methods BMSCs were extracted from patients with normal bone density and categorized into the normal control group(CON group). BMSCs extracted from patients with primary osteoporosis were categorized into the primary osteoporosis group (POP group). The cells from the POP group were treated with a PPARγ inhibitor and divided into the inhibitor group (INR group). Following osteogenic differentiation, the expression of osteopontin (OPN), osteocalcin (OCN), Osterix, and runt-related transcription factor 2 (Runx2) was evaluated in the cells of each group.The alkaline phosphatase (ALP) staining was employed to assess the osteogenic differentiation of BMSCs in each group. Results The quantity of ALP-positive cells in the POP group was lower than that in the CON and INR groups (P < 0.05). The expression of OCN, OPN, Osterix, and Runx2 was found to be decreased in the POP group when compared to the CON group, with statistically significant differences (P < 0.05). Conversely, the expression of OCN, OPN, Osterix, and Runx2 was elevated in the INR group when compared to the POP group, with statistically significant differences (P < 0.05). Conclusion Increased expression of osteogenic differentiation-specific genes (ALP, OCN, OPN, Osterix, Runx2) in BMSCs after inhibition of PPARγ expression. -
Key words:
- POP /
- PPARγ /
- BMSCs /
- Osteogenic differentiation
-
岗松 (Baeckeafrutescens)为桃金娘科 (Myrtaceae) 岗松属 (BaeckeaL.) 植物,是南方民间的常用著名药材。以叶如松针较短而得名,又名鸡儿松、松毛枝、长松、沙松等。全球约有68种岗松属植物,而我国仅有岗松一个种,主要分布于海南、广东、广西、福建、浙江、江西等省份[1]。岗松属植物主要含有挥发油、间苯三酚、黄酮类、萜类等化学成分。其中,二氢黄酮类成分是一种的具有广泛的药理作用的化合物,如抗癌[2]、PTP1B抑制[3]、抗氧化[4]、抗菌[5]和抗炎[6-7]等活性。具有生物活性的天然产物一直以来都是治疗各种疾病的新药的最有价值的来源之一[8]。
作为本研究组对桃金娘科植物中活性次生代谢产物挖掘研究工作的一部分,本研究从岗松的枝叶中分离得到5个二氢黄酮类化合物,图1,其中化合物1、3和5为首次从该植物中分离得到。尽管这些成分已被报道[9-16],但它们的绝对构型报道较混乱。因此,笔者采用手性拆分、ORD和ECD计算的方法进一步确定了它们的绝对构型。此外,评价了这些成分对4种人肿瘤细胞株(HCT116、Hela、DU145和A549)的细胞毒活性。
1. 材料与方法
1.1 材料与仪器
旋光数据在AUTOPOL Ⅵ旋光仪上测定;圆二色谱在Applied Photophysics分光偏振计上测定;NMR谱在Bruker Avance Ⅲ-500核磁共振仪上测定,TMS作为内标;ESI-MS在Agilent 1290 UPLC/6540 Q-TOF质谱仪上测定;硅胶 (80~100目,200~300目,中国青岛海祥化工厂);凝胶为Sephadex LH-20 (40~70 μm;Healthcare BioSciences AB,Uppsala, Sweden),反相填充材料Rp-18(50 μm, 德国Merck公司);半制备型HPLC为Agilent 1260型高效液相色谱;色谱柱为ZORBAXSB-C18柱 (9.4 × 250 mm, 5.0 μm) , CHIRALPAK IC (4.64 × 250 mm, 10 × 250 mm, 5.0 μm)柱。
1.2 植物标本来源
岗松 (B. frutescens) 枝叶于2016年10月采自广西壮族自治区东兴市,由中国科学院昆明植物研究所李嵘研究员鉴定。标本保存于中国科学院昆明植物研究所植物化学与西部植物资源持续利用国家重点实验室刘海洋课题组。
1.3 实验方法
1.3.1 提取分离
岗松枝叶 (10.0 kg) 粉碎后甲醇回流提取3次,合并提取液,减压回收甲醇,得到浸膏1.3 kg。浸膏用1.0 kg 硅胶 (80~100 目)拌样,2.0 kg 硅胶 (200~300 目)装柱,用石油醚-乙酸乙酯 (1∶0→0∶1,v/v) 和氯仿-甲醇 (1∶0→1∶1,v/v) 梯度洗脱得到七个 (Fr.1-Fr.7) 不同馏分。Fr.2 (53 g) 用正相硅胶划段(石油醚-丙酮,1∶0→1∶1,v/v)后,合并为三个馏分,经反复使用Rp-18色谱柱(甲醇-水,1∶1→1∶0,v/v),硅胶柱层析 (石油醚-丙酮,10∶1→1∶1,v/v), Sephadex LH-20色谱柱(氯仿-甲醇,1∶1,v/v)及半制备HPLC(乙腈-水,60%→80%,v/v)分离纯化得到了化合物1 (81.1 mg)、2 (23.6 mg)和3(401.5 mg)。Fr. 5 (48 g) 用MCI gel脱色,脱色后经Rp-18色谱柱 (甲醇-水,1∶1→1∶0,v/v),硅胶柱层析(氯仿-甲醇,1∶1,v/v),进一步使用半制备HPLC(乙腈-水,30%→50%,v/v)分离纯化得到了化合物4 (7.2 mg)和5 (118.7 mg)。
1.3.2 手性分析及拆分
分离得到的化合物1-5分别进行HPLC手性分析 (色谱柱:CHIRALPAK I,4.64 × 250 mm, 5.0 μm; 色谱条件:正己烷-异丙醇,1∶0→3∶2, v/v, 30 min) , 显示化合物1和3只有一个峰,化合物2、4和5分别都有两个峰(图2)。进一步手性拆分 (色谱柱:CHIRALPAK I,10 × 250 mm, 5.0 μm; 色谱条件:正己烷-异丙醇,70∶30,v/v),分离得到(+)-2,(-)-2,(+)-4,(-)-4, (+)-5和(-)-5。
1.3.3 计算方法
ORD和ECD的计算主要通过Gaussian 16软件来实现的。首先,化合物1和2的构象通过CONFLEX 8B软件进行了分析,并分别给出了3个 (图3)和1个 (图4) 可用构象。这些初始结构通过密度泛函理论 (DFT) 在B3LYP/6-31+G(d) 水平上进行了优化。优化后构象的ECD计算通过依时性密度泛函理论 (TDDFT) 在B3LYP/6-311++G (2d, p) 水平上进行,而ORD计算则通过依时性密度泛函理论 (TDDFT) 在B3LYP/6-31++G (d, p) 水平上进行。计算后的ECD图谱通过SpecDis 1.6软件来实现其可视化。
1.3.4 细胞毒活性
在96孔微孔板上使用MTT法评估化合物1‒5对四种人肿瘤细胞株 (HCT116、CCRF-CEM、DU145和A549)的细胞毒活性。对化合物进行了5个剂量测试,剂量范围为10‒8~10‒4 M,各化合物的IC50值通过非线性回归分析计算。以广谱抗肿瘤药喜树碱(CPT)为阳性对照,每个试验重复3次。
2. 结果
化合物1:淡黄色粉末C16H14O6;negative ESI-MSm/z 269 [M‒H]‒;[α] ‒46.8 (c = 0.22,MeOH);ECD (MeOH) λmax (Δε)220 (+3.26),237 (‒0.08),256 (+0.79),281 (‒3.56),336 (+0.46) nm;1H NMR(Acetone-d6,500 MHz) δ: 5.51 (1H,dd,J = 12.9,2.7 Hz,H-2),1.97 (3H,s,H3-6),6.07 (1H,s,H-8),7.38 (1H,m,H-4′ ),7.43 (2H,m,H-3′ /H-5′ ),7.55 (2H,d,J = 7.4 Hz,H-2′ /H-6′ ),12.42 (1H,s,OH-5),3.31 (1H,dd,J = 17.1,12.9 Hz,H-3a),2.78 (1H,dd,J = 17.1,2.7 Hz,H-3b);13C NMR (Acetone-d6,125 MHz)δ: 79.9 (C-2),43.7 (C-3),196.8 (C-4),162.4 (C-5),104.8 (C-6),7.0 (6-CH3),165.1 (C-7),95.2 (CH-8),161.6 (C-9),103.0 (C-10),140.2 (C-1′ ),127.3 ×2 (CH-2′ /CH-6′ ),129.4 ×2 (CH-3′ /CH-5′ ),129.3 (CH-4′ )。以上数据与文献[10]报道的5,7-二羟基-6-甲基二氢黄酮的数据基本一致。
初步ORD计算结果表明, (2R)-1的比旋光值为正值(+180.38), 而化合物1的测试比旋光值为‒46.8 (c = 0.22,MeOH), 由此推断化合物1为2S构型,此结论通过后续的ECD计算(图5)结果进一步得到证实。
化合物2:淡黄色粉末C17H16O4;negative ESI-MSm/z283 [M -H]-; [α] +21.5 (c = 0.14, MeOH) for (+)-2, [α] -21.4 (c = 0.14, MeOH) for (-)-2; ECD (MeOH) λmax (Δε)220 (-3.20), 242 (-0.19), 254 (-0.41), 287 (+2.79), 338 (-0.43) nm for (+)-2, ECD (MeOH) λmax (Δε)220 (+3.20), 237 (+0.19), 256 (+0.41), 287 (+2.79), 338 (+0.43) nm for (-)-2; 1H NMR (CDCl3, 500 MHz) δ: 2.01 (3H, s, CH3-6), 2.86 (1H, dd, J = 17.1, 3.1 Hz, H-3b), 3.04 (1H, dd, J = 17.1, 12.7 Hz, H-3a), 3.86 (3H, s, OCH3-7), 5.42 (1H, dd, J = 12.7, 3.1 Hz, H-2), 6.10 (1H, s, H-8), 7.36~7.48 (5H, m, H-2'-H-6'), 12.12 (1H, s, OH-5); 13C NMR data (CDCl3, 125 MHz)δ: 78.5 (C-2), 43.5 (C-3), 196.3 (C-4), 162.4 (C-5), 105.0 (C-6), 166.0 (C-7), 92.3 (C-8), 158.9 (C-9), 102.9 (C-10), 139.0 (C-1'), 125.9 (C-2'), 128.8 (C-3'), 128.6 (C-4'), 128.8 (C-5'), 125.9 (C-6'), 7.6 (6-Me), 55.9 (7-OMe). 13C NMR data显示其与化合物1高度相似,主要区别在于多了一个甲氧基的信号。化合物2与文献[11]报道的化合物5-羟基-7-甲氧基-6-甲基二氢黄酮数据基本一致。经进一步手性拆分并结合ECD计算结果 (图6) 分别确定(+)-2 {[α] +21.5 (c = 0.14, MeOH)} 和(-)-2{[α]-21.4 (c = 0.14, MeOH)}的绝对构型分别为2R和2S。
化合物3:淡黄色粉末C17H16O4; negative ESI-MS m/z269 [M ‒H]‒; [α] ‒20.8 (c = 0.12, MeOH); 1H NMR (CDCl3, 500 MHz)δ: 2.82 (1H, dd, J = 17.2, 3.1Hz, H-3b), 3.08 (1H, dd, J = 17.2, 13.1Hz, H-3a), 3.80 (3H, s, OCH3-7), 5.41 (1H, dd, J = 13.1, 3.1 Hz, H-2), 6.06 (1H, d, J = 2.3Hz, H-6), 6.08 (1H, d, J = 2.3Hz, H-8), 7.37~7.47 (5H, m, H-2'‒H-6'), 12.03 (1H, s, OH-5); 13C NMR data (CDCl3, 125 MHz)δ: 79.3 (C-2), 43.4 (C-3), 195.8 (C-4), 164.2 (C-5), 95.2 (C-6), 168.0 (C-7), 94.3 (C-8), 162.8 (C-9), 103.2 (C-10), 138.4 (C-1'), 126.2 (C-2'), 128.9 (C-3'), 128.9 (C-4'), 128.9 (C-5'), 126.2 (C-6'), 55.7(7-OMe)。以上数据与文献报道的(2S)-乔松酮[11,12]数据基本一致。通过与化合物1的比旋光值对比而判定其绝对构型为2S。
化合物4:淡黄色粉末C17H16O4; negative ESI-MS m/z283 [M ‒H]‒; [α]+38.5 (c = 0.16, MeOH) for (+)-4,[α]‒38.6 (c = 0.16, MeOH) for (‒)-4;ECD (MeOH) λmax (Δε) 218 (‒3.45), 243 (‒0.17), 254 (‒0.41), 289 (+3.00), 338 (‒0.44) nm for (+)-4, ECD (MeOH) λmax (Δε) 218 (+3.45), 243 (+0.17), 254 (+0.41), 289 (‒3.00), 338 (+0.44) nm for (‒)-4; 1H NMR (CDCl3, 500 MHz) δ: 2.01 (3H, s, CH3-6), 2.84 (1H, dd, J = 3.1, 3.1 Hz, H-3b), 3.04 (1H, dd, J = 3.1, 3.1 Hz, H-3a), 3.86 (3H, s, OCH3-7), 5.42 (1H, dd, J = 3.1, 3.1 Hz, H-2), 6.10 (1H, s, H-6), 7.42 (5H, m, H-2'‒H-6'), 12.12 (1H, s, OH-5); 13C NMR data (CDCl3, 125 MHz)δ: 78.5 (C-2), 43.4 (C-3), 196.3 (C-4), 162.4 (C-5), 92.2 (C-6), 166.0 (C-7), 104.9 (C-8), 158.8 (C-9), 102.8 (C-10), 138.9 (C-1'), 125.8 (C-2'), 128.8 (C-3'), 128.5 (C-4'), 128.8 (C-5'), 125.8 (C-6'), 55.9 (7-OMe), 7.5 (8-Me)。以上数据与文献报道的(±)-5-羟基-7-甲氧基-8-甲基二氢黄酮[13-14]数据基本一致。
化合物5:淡黄色粉末C17H16O4; negative ESI-MS m/z283 [M ‒H]‒; [α]‒41.5 (c = 0.18, MeOH) for (‒)-5;ECD (MeOH) λmax (Δε) 208(‒0.93), 219 (‒3.42), 243 (‒0.35), 254 (‒0.41), 292 (+3.21), 338 (‒0.54) nm for (+)-5, ECD (MeOH) λmax (Δε) 208 (+0.93), 219 (+3.42), 243 (+0.35), 254 (+0.41), 292 (‒3.21), 338 (+0.54) nm for (‒)-5; 1H NMR (Pyridine-d5, 500 MHz) δ: 2.39 (3H, s, CH3-6), 2.92 (1H, J = 17.0, 2.6 Hz, H-3a), 3.33 (1H, J = 17.0, 13.0 Hz, H-3b), 5.49 (1H, dd, J = 13.0, 2.6 Hz, H-2), 7.10 (1H, d, J = 8.1 Hz, H-5'), 7.27 (1H, d, J = 8.1 Hz, H-6'), 7.52 (1H, s, H-2'), 13.03 (1H, s, OH-5); 13C NMR data (Pyridine-d5, 125 MHz)δ:79.9 (C-2), 43.6 (C-3), 196.6 (C-4), 162.3 (C-5), 105.0 (C-6), 166.3 (C-7), 95.1 (C-8), 161.6 (C-9), 102.7 (C-10), 130.9 (C-1'), 115.4 (C-2'), 147.5 (C-3'), 147.9 (C-4'), 116.5 (C-5'), 118.8 (C-6'), 7.7 (6-Me)。以上数据与文献报道的(±)-6-甲基-圣草酚[15-16]数据基本一致。
通过与化合物2的测试ECD图谱对比,(+)-4/(+)-5和(‒)-4/(‒)-5的绝对构型分别确定为2R和2S,见图7。
以广谱抗肿瘤药喜树碱 (CPT) 为阳性对照,评价了以上化合物对4种人肿瘤细胞株 (HCT116、CCRF-CEM、DU145和A549)的细胞毒活性。结果显示化合物(±)-2对HCT116和DU145有一定的活性,IC50值分别为(41.84 ± 3.66) μΜ和(13.54 ± 1.15) μΜ;而化合物3对DU145的具有显著的细胞毒活性,IC50值为(4.56 ± 0.42) μΜ。
3. 讨论
从岗松中分离得到5个二氢黄酮类化合物,通过NMR和MS数据分析以及ORD和ECD计算确定了它们的结构及其绝对构型,其中化合物1、3和5为首次从该植物中分离得到。化合物3对DU145的具有显著的细胞毒活性,IC50值为4.56 μM。从自然界中得到的手性天然产物通常被认为是以光学纯形式生物合成的[17],但是已有大量的外消旋体或富含对映体的混合物已从自然来源报道[18]。有趣的是,岗松中的二氢黄酮类成分分别以光学纯 (1和3)、外消旋体 (4)和不对等对映体 (2和5)三种形式存在,此发现为二氢黄酮对映体的生物合成途径提供了一定证据。尽管比旋光值在一定程度上是判定光学纯单体绝对构型的重要指标之一[18],但在实际科学研究过程中,不对等对映体的实测值实际上是由对映体过量部分产生的,从而产生误判。因此,对于天然手性产物的立体异构体组成的评价理应引起更多的关注。
-
表 1 免疫荧光半定量方差分析($ \bar x \pm s $,n = 3)
Table 1. The ANOVA for semi-quantification of immunofluorescence ($ \bar x \pm s $,n = 3)
组别 平均荧光强度 CON组 27.65±3.93 POP组 105.98±13.95 INR组 40.72±13.20 F 41.229 P <0.001* *P < 0.05。 表 2 各组基因相对表达量($ \bar x \pm s $,n = 3)
Table 2. Relative expression of genes in each group($ \bar x \pm s $,n = 3)
组别 OCN OPN Osterix Runx2 CON组 0.95±0.07 1.21±0.20 1.20±0.17 1.23±0.20 POP组 0.40±0.07 0.46±0.03 0.58±0.11 0.48±0.04 INR组 0.66±0.05 0.80±0.03 0.85±0.12 0.86±0.16 F 59.832 31.647 15.947 19.007 P <0.001* 0.001* 0.004* 0.003* *P < 0.05。 表 3 各组蛋白相对表达量($ \bar x \pm s $,n = 3)
Table 3. Expression levels of each group of proteins($ \bar x \pm s $,n = 3)
组别 OCN OPN Osterix Runx2 CON组 0.74±0.07 0.44±0.06 0.55±0.02 0.54±0.16 POP组 0.51±0.11 0.3±0.03 0.22±0.03 0.31±0.08 INR组 0.89±0.28 0.51±0.03 0.38±0.06 0.52±0.02 F 7.189 37.672 93.211 9.690 P 0.006* <0.001* <0.001* 0.002* *P < 0.05。 -
[1] 中华医学会骨质疏松和骨矿盐疾病分会. 原发性骨质疏松症诊疗指南(2022)[J]. 中国全科医学,2023,26(14):1671-1691. [2] Muruganandan S,Ionescu A M,Sinal C J. At the crossroads of the adipocyte and osteoclast differentiation programs: Future therapeutic perspectives[J]. International Journal of Molecular Sciences,2020,21(7):2277. doi: 10.3390/ijms21072277 [3] Wu H,Li X,Shen C. Peroxisome proliferator-activated receptor gamma in white and brown adipocyte regulation and differentiation[J]. Physiological Research,2020,69(5):759-773. [4] Vita F,Gangemi S,Pioggia G,et al. Physical activity and post-transcriptional regulation of aging decay: Modulation of pathways in postmenopausal osteoporosis[J]. Medicina-Lithuania,2022,58(6):767. [5] Li X,Ning L,Ma J,et al. The PPAR-γ antagonist T007 inhibits RANKL-induced osteoclastogenesis and counteracts OVX-induced bone loss in mice[J]. Cell Communication and Signaling: CCS,2019,17(1):136. doi: 10.1186/s12964-019-0442-3 [6] Lee M J. Hormonal regulation of adipogenesis[J]. Comprehensive Physiology,2017,7(4):1151-1195. [7] Yu B,Wang CY. Osteoporosis and periodontal diseases - an update on their association and mechanistic links[J]. Periodontology,2000,2022,89(1):99-113. [8] Agidigbi T S,Kim C. Reactive oxygen species in osteoclast differentiation and possible pharmaceutical targets of ros-mediated osteoclast diseases[J]. International Journal of Molecular Sciences,2019,20(14):3576. doi: 10.3390/ijms20143576 [9] Domazetovic V,Marcucci G,Iantomasi T,et al. Oxidative stress in bone remodeling: role of antioxidants[J]. Clinical Cases in Mineral and Bone Metabolism,2017,14(2):209-216. doi: 10.11138/ccmbm/2017.14.1.209 [10] Zhou Q,Zhu L,Zhang D,et al. Oxidative stress-related biomarkers in postmenopausal osteoporosis: A systematic review and meta-analyses[J]. Disease Markers,2016,2016:7067984. [11] Abdallah B M. Marrow adipocytes inhibit the differentiation of mesenchymal stem cells into osteoblasts via suppressing bmp-signaling[J]. Journal of Biomedical Science,2017,24(1):11-11. doi: 10.1186/s12929-017-0321-4 [12] Chandra A,Rajawat J. Skeletal aging and osteoporosis: Mechanisms and therapeutics[J]. International Journal of Molecular Sciences,2021,22(7):3553. doi: 10.3390/ijms22073553 [13] Ahmadian M,Suh J M,Hah N,et al. PPARγ signaling and metabolism: the good,the bad and the future[J]. Nature Medicine,2013,19(5):557-566. doi: 10.1038/nm.3159 [14] Cao J,Ou G,Yang N,et al. Impact of targeted PPARγ disruption on bone remodeling[J]. Mol Cell Endocrinol,2015,410:27-34. doi: 10.1016/j.mce.2015.01.045 [15] Albers J,Keller J,Baranowsky A,et al. Canonical wnt signaling inhibits osteoclastogenesis independent of osteoprotegerin[J]. The Journal of Cell Biology,2013,200(4):537-549. doi: 10.1083/jcb.201207142 [16] Li Y,Yao L,Lu J. IL-35 inhibits adipogenesis via PPARγ-wnt/β-catenin signaling pathway by targeting axin2[J]. Int Immunopharmacol,2023,122:110615. doi: 10.1016/j.intimp.2023.110615 [17] Komori T. Regulation of proliferation,differentiation and functions of osteoblasts by runx2[J]. Int J Mol Sci,2019,20(7):1694. doi: 10.3390/ijms20071694 -