Aortic Msx2-Wnt calcification cascade is regulated by TNF-alpha-dependent signals in diabetic Ldlr-/- mice.
OBJECTIVE
Aortic calcification is prevalent in type II diabetes (T2DM), enhancing morbidity and tracking metabolic syndrome parameters. Ldlr(-/-) mice fed high-fat "Westernized" diets (HFD) accumulate aortic calcium primarily in the tunica media, mediated via osteogenic morphogens and transcriptional programs that induce aortic alkaline phosphatase (ALP). Because elevated TNF-alpha is characteristic of obesity with T2DM, we examined contributions of this inflammatory cytokine.


RESULTS
HFD promoted obesity, hyperglycemia, and hyperlipidemia, and upregulated serum TNF-alpha in Ldlr(-/-) mice. Serum haptoglobin (inflammatory marker) was increased along with aortic expression of BMP2, Msx2, Wnt3a, and Wnt7a. Dosing with the TNF-alpha neutralizing antibody infliximab did not reduce obesity, hypercholesterolemia, or hyperglycemia; however, haptoglobin, aortic BMP2, Msx2, Wnt3a, and Wnt7a and aortic calcium accumulation were downregulated by infliximab. Mice with vascular TNF-alpha augmented by a transgene (SM22-TNFalphaTg) driven from the SM22 promoter upregulated aortic Msx2, Wnt3a, and Wnt7a. Furthermore, SM22-TNFalphaTg;TOPGAL mice exhibited greater aortic beta-galactosidase reporter staining versus TOPGAL sibs, indicating enhanced mural Wnt signaling. In aortic myofibroblast cultures, TNF-alpha upregulated Msx2, Wnt3a, Wnt7a, and ALP. ALP induction was inhibited by Dkk1, an antagonist of paracrine Wnt actions.


CONCLUSIONS
TNF-alpha promote aortic Msx2-Wnt programs that contribute to aortic calcium accumulation in T2DM.
Al-Aly
Ziyad
Z
Division of Bone and Mineral Diseases, Washington University School of Medicine, Campus Box 8301, 660 South Euclid Avenue, St. Louis, MO 63110. dtowler@im.wustl.edu.
Shao
Jian-Su
JS
Lai
Chung-Fang
CF
Huang
Emily
E
Cai
Jun
J
Behrmann
Abraham
A
Cheng
Su-Li
SL
Towler
Dwight A
DA
D000469:Alkaline Phosphatase; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000494:pharmacology / Q000627:therapeutic use; D001011:Aorta / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D001018:Aortic Diseases / Q000209:etiology / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002114:Calcinosis / Q000209:etiology / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000139:chemically induced / Q000150:complications / Q000378:metabolism* / Q000473:pathology; D004041:Dietary Fats / Q000008:administration & dosage; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000201:enzymology / Q000378:metabolism; D006242:Haptoglobins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D000069285:Infliximab; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008840:Microfilament Proteins / Q000235:genetics; D009124:Muscle Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D011973:Receptors, LDL / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D060508:Wnt3 Protein; D060509:Wnt3A Protein
D000893:Anti-Inflammatory Agents; D000911:Antibodies, Monoclonal; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D004041:Dietary Fats; C501127:Dkk1 protein, mouse; D006242:Haptoglobins; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; C084119:MSX2 protein; D008840:Microfilament Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D011973:Receptors, LDL; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse; C490508:Wnt7a protein, mouse; C051615:transgelin; D000069285:Infliximab; D000469:Alkaline Phosphatase