Expression of Cytosolic NADP + -Dependent Isocitrate Dehydrogenase in Bovine Mammary Epithelium: Modulation by Regulators of Differentiation and Metabolic Effectors
Restricted accessResearch articleFirst published online May, 2006
Expression of Cytosolic NADP + -Dependent Isocitrate Dehydrogenase in Bovine Mammary Epithelium: Modulation by Regulators of Differentiation and Metabolic Effectors
The cytosolic NADP+-dependent isocitrate dehydrogenase (IDH1) catalyzes the conversion of isocitrate to α-ketoglutarate in the cytosol, and generates NADPH as a primary source of reducing equivalents for de novo fatty acid synthesis in bovine mammary gland. The enzymatic activity of IDH1 increases dramatically in early lactation in bovine mammary tissue. We hypothesized that the expression of IDH1 in bovine is modulated by regulators of mammary epithelial differentiation. To test this hypothesis, we first examined the changes in IDH1 expression in late pregnancy (20 days) and at various stages (14, 90, 120, and 240 days) of lactation in bovine mammary tissue. IDH1 mRNA levels increased by 2.3-fold after parturition compared to late pregnancy and remained elevated thereafter. Next, we examined the effects of extracellular matrix and lactogenic hormones on the expression of IDH1 in cultured BME-UV bovine mammary epithelial cells. We found that expression of IDH1 mRNA increased in parallel with β-casein expression induced by extracellular matrix. Fetal calf serum and insulin repressed, whereas prolactin stimulated the expression of IDH1 mRNA in a dose-dependent fashion. The inhibitory effects of insulin on IDH1 mRNA levels were antagonized by cotreatment with prolactin. In contrast, treatment with prolactin in the presence of extracellular matrix further increased IDH1 mRNA and protein accumulation. Prolactin-induced IDH1 expression was inhibited by the mitogen-activated protein kinase (MAPK) inhibitors PD98059 and U0126, and Janus tyrosine kinase 2 (Jak2) inhibitor AG490, suggesting that both MAPK and Jak2 contribute to regulation of IDH1 expression by prolactin. Finally, we report that treatment of BME-UV cells with α-ketoglutarate and palmitic acid reduced IDH1 transcript levels. Taken together, our data suggest that the expression of IDH1 in bovine mammary epithelium is modulated by regulators of differentiation including extracellular matrix and lactogenic hormones as well as metabolic effectors.
GálvezS, GadalP. On the function of the NADP-dependent isocitrate dehydrogenase isoenzymes in living organisms. Plant Sci105: 1–14, 1995.
2.
PlautGWE, CookM, AogaichiT. The subcellular location of isozymes of NADP-isocitrate dehydrogenase in tissues from pig, ox and rat. Biochim Biophys Acta760: 300–308, 1983.
3.
ChenRD, GadalP. Structure, functions and regulation of NAD and NADP dependent isocitrate dehydrogenases in higher plants and in other organisms. Plant Physiol Biochem28: 411–427, 1990.
4.
ChenRF, PlautGWE. Activation and inhibition of DPN-linked isocitrate dehydrogenase of heart by certain nucleotide. Biochemistry2: 1023–1032, 1963.
5.
PlautGWE. DPN-linked isocitrate dehydrogenase of animal tissues. Curr Top Cell Regul2: 1–27, 1970.
6.
GabrielJL, PlautGWE. Citrate activation of NAD-specific isocitrate dehydrogenase from bovine heart. J Biol Chem259: 1622–1628, 1984.
7.
HaselbeckRJ, McAlister-HennL. Function and expression of yeast mitochondrial NAD- and NADP-specific isocitrate dehydrogenase. J Biol Chem268: 12116–12122, 1993.
8.
KirkmanHN, GaetaniGF. Catalase: a tetrameric enzyme with four tightly bound molecules of NADPH. Proc Natl Acad Sci U S A81: 4343–4347. 1984.
9.
ScottMD, ZuoL, LubinBH, and ChiuDT. NADPH, not glutathione, status modulates oxidant sensitivity in normal and glucose-6-phosphate dehydrogenase-deficient erythrocytes. Blood77: 2059–2064, 1991.
10.
BaumanDE, BrownRE, DavisCL. Pathways of fatty acid synthesis and reducing equivalent generation in mammary gland of rat, sow, and cow. Arch Biochem Biophys140: 237–244, 1970.
11.
HardwickDC, LinzellJL, MephamTB. The metabolism of acetate and glucose by the isolated perfused udder 2. The contribution of acetate and glucose to carbon dioxide and milk constituents. Biochem J88: 213–220, 1963.
12.
HardwickDC. The fate of acetyl groups derived from glucose in the isolated perfused goat udder. Biochem J99: 228–231, 1966.
13.
BallardFJ, HansonRW. The citrate cleavage pathway and lipogenesis in rat adipose tissue: replenishment of oxaloacetate. J Lipid Res8: 73–79, 1967.
14.
FarrellHMJr., DeeneyJT, TubbsK, WalshRA. Role of the isocitrate dehydrogenases and other Krebs cycle enzymes in lactating bovine mammary gland. J Dairy Sci70: 781–788, 1987.
15.
ZavizionB, van DuffelenM, SchaefferW, PolitisI. Establishment and characterization of a bovine mammary epithelial cell line with unique properties. In Vitro Cell Dev Biol Anim32: 38–48, 1996.
16.
ConnorEE, WoodDL, SonstegardTS, MotaAF, BennettGL, WilliamsJL, CapucoAV. Chromosomal mapping and quantitative analysis of estrogen-related receptor alpha-1, estrogen receptors alpha and beta and progesterone receptor in the bovine mammary gland. J Endocrinol185: 593–603, 2005
17.
RomagnoloD, AkersRM, WongEA, BoylePL, McFaddenTB, ByattJC, TurnerJD. Lactogenic hormones and extracellular matrix regulate expression of IGF-1 linked to MMTV-LTR in mammary epithelial cells. Mol Cell Endocrinol96: 147–157, 1993.
18.
StreuliCH. Extracellular matrix and gene expression in mammary epithelium. Semin Cell Biol4: 203–212, 1993.
19.
TopperYJ, and FreemanCS. Multiple hormone interactions in the developmental biology of the mammary gland. Physiol Rev60: 1049–1106, 1980.
20.
WatsonCJ, BurdonTG. Prolactin signal transduction mechanisms in the mammary gland: the role of the Jak/Stat pathway. Rev Reprod1: 1–5, 1996.
21.
McNamaraJP. Regulation of adipose tissue metabolism in support of lactation. J Dairy Sci74: 706–719, 1991.
22.
NevilleMC, McFaddenTB, ForsythI. Hormonal regulation of mammary differentiation and milk secretion. J Mammary Gland Biol Neoplasia7: 49–66, 2002.
23.
ShechterI, DaiP, HuoL, GuanG. IDH1 gene transcription is sterol regulated and activated by SREBP-1a and SREBP-2 in human hepatoma HepG2 cells: evidence that IDH1 may regulate lipogenesis in hepatic cells. J Lipid Res44: 2169–2180, 2003.
24.
LiML, AggelerJ, FarsonDA, HatierC, HassellJ, BissellMJ. Influence of a reconstituted basement membrane and its components on casein gene expression and secretion in mouse mammary epithelial cells. Proc Natl Acad Sci U S A84: 136–140, 1987.
25.
Barcellos-HoffMH, AggelerJ, RamTG, BissellMJ. Functional differentiation and alveolar morphogenesis of primary mammary cultures on reconstituted basement membrane. Development105: 223–235, 1989.
26.
KeelyPJ, FongAM, ZutterMM, SantoroSA. Alteration of collagen-dependent adhesion, motility, and morphogenesis by the expression of antisense alpha 2 integrin mRNA in mammary cells. J Cell Sci108: 595–607, 1995.
27.
KeelyPJ, WuJE, SantoroSA. The spatial and temporal expression of the alpha 2 beta 1 integrin and its ligands, collagen I, collagen IV, and laminin, suggest important roles in mouse mammary morphogenesis. Differentiation59: 1–13, 1995.
28.
SchmidhauserC, BissellMJ, MyersCA, CaspersonGF. Extracellular matrix and hormones transcriptionally regulate bovine beta-casein 5′ sequences in stably transfected mouse mammary cells. Proc Natl Acad Sci U S A87: 9118–9122, 1990.
29.
DopplerW, GronerB, BallRK. Prolactin and glucocorticoid hormones synergistically induce expression of transfected rat beta-casein gene promoter constructs in a mammary epithelial cell line. Proc Natl Acad Sci U S A86: 104–108, 1989.
30.
PeelCJ, TaylorJW, RobinsonIB, McGowanAA, HooleyRD, FindlayJK. The importance of prolactin and the milking stimulus in the artificial induction of lactation in cows. Aust J Biol Sci31: 187–195, 1978.
31.
AkersRM, BaumanDE, CapucoAV, GoodmanGT, TuckerHA. Prolactin regulation of milk secretion and biochemical differentiation of mammary epithelial cells in periparturient cows. Endocrinology109: 23–30, 1981.
32.
VernonRG, FlintDJ. Control of fatty acid synthesis in lactation. Proc Nutr Soc42: 315–331, 1983.
BarberMC, FinleyE, VallanceAJ, VernonRG. The effect of prolactin on acetyl-CoA carboxylase activity in mammary explants from pregnant sheep. Biochem Soc Trans18: 1259, 1990.
ObenJE, DilsRR. Prolactin-stimulated polymerization of acetyl-coA carboxylase in explants of mid-pregnant rat mammary gland. J Dairy Res68: 351–355, 2001.
37.
NevilleMC, PiccianoMF. Regulation of milk lipid secretion and composition. Annu Rev Nutr17: 159–183, 1997.
38.
VallanceWS, McClymontGL. Depression in percentage of milk fat by parenteral glucose infusion and glycerol feeding. Nature183: 466–467, 1959.
39.
McGuireMA, GriinariJM, DwyerDA, BaumanDE. Role of insulin in the regulation of mammary synthesis of fat and protein. J Dairy Sci78: 816–824, 1995.
40.
GriinariJM, McGuireMA, DwyerDA, BaumanDE, PalmquistDL. Role of insulin in the regulation of milk fat synthesis in dairy cows. J Dairy Sci80: 1076–1084, 1997.
41.
NickersonSC, HealdCW, BibbTL, McGilliardML. Cytological effects of hormones and plasma on bovine mammary tissue in vitro. J Endocrinol79: 363–368, 1978.
42.
ImagawaW, TomookaY, HamamotoS, NandiS. Stimulation of mammary epithelial cell growth in vitro: interaction of epidermal growth factor and mammogenic hormones. Endocrinology116: 1514–1524, 1985.
Bole-FeysotC, GoffinV, EderyM, BinartN, KellyPA. Prolactin (PRL) and its receptor: actions, signal transduction pathways and phenotypes observed in PRL receptor knockout mice. Endocr Rev19: 225–268, 1998.
45.
DasR, VonderhaarBK. Activation of raf-1, MEK, and MAP kinase in prolactin responsive mammary cells. Breast Cancer Res Treat40: 141–149, 1996.
46.
DasR, VonderhaarBK. Involvement of SHC, GRB2, SOS and RAS in prolactin signal transduction in mammary epithelial cells. Oncogene13: 1139–1145, 1996.
47.
AlessiDR, CuendaA, CohenP, DudleyDT, SaltielAR. PD 098059 is a specific inhibitor of the activation of mitogen-activated protein kinase kinase in vitro and in vivo. J Biol Chem270: 27489–27494, 1995.
48.
AlvaradoA, FloresME. Characterization and regulation of NADP+-isocitrate dehydrogenase from Saccharopolyspora erythraea. Biotechnol Lett25: 1175–1178, 2003.
49.
CaronRW, JahnGA, DeisRP. Lactogenic actions of different growth hormone preparations in pregnant and lactating rats. J Endocrinol142: 535–545, 1994.
50.
BussmannLE, BussmannIM, CharreauEH. Role of receptors for epidermal growth factor and insulin-like growth factors I and II in the differentiation of rat mammary glands from lactogenesis I to lactogenesis II. J Reprod Fertil107: 307–314, 1996.
51.
HoveyRC, TrottJF, VonderhaarBK. Establishing a framework for the functional mammary gland: from endocrinology to morphology. J Mammary Gland Biol Neoplasia7: 17–38, 2002.
