Adipocyte and Cell Biology

GALNT2 as a novel modulator of adipogenesis and adipocyte insulin signaling



A better understanding of adipose tissue biology is crucial to tackle insulin resistance and eventually coronary heart disease and diabetes, leading causes of morbidity and mortality worldwide. GALNT2, a GalNAc-transferase, positively modulates insulin signaling in human liver cells by down-regulating ENPP1, an insulin signaling inhibitor. GALNT2 expression is increased in adipose tissue of obese as compared to that of non-obese individuals. Whether this association is secondary to a GALNT2-insulin sensitizing effect exerted also in adipocytes is unknown. We then investigated in mouse 3T3-L1 adipocytes the GALNT2 effect on adipogenesis, insulin signaling and expression levels of both Enpp1 and 72 adipogenesis-related genes.


Stable over-expressing GALNT2 and GFP preadipocytes (T0) were generated. Adipogenesis was induced with (R+) or without (R−) rosiglitazone and investigated after 15 days (T15). Lipid accumulation (by Oil Red-O staining) and intracellular triglycerides (by fluorimetric assay) were measured. Lipid droplets (LD) measures were analyzed at confocal microscope. Gene expression was assessed by RT-PCR and insulin-induced insulin receptor (IR), IRS1, JNK and AKT phosphorylation by Western blot.


Lipid accumulation, triglycerides and LD measures progressively increased from T0 to T15R- and furthermore to T15R+. Such increases were significantly higher in GALNT2 than in GFP cells so that, as compared to T15R+GFP, T15R- GALNT2 cells showed similar (intracellular lipid and triglycerides accumulation) or even higher (LD measures, p < 0.01) values. In GALNT2 preadipocytes, insulin-induced IR, IRS1 and AKT activation was higher than that in GFP cells. GALNT2 effect was totally abolished during adipocyte maturation and completely reversed at late stage maturation. Such GALNT2 effect trajectory was paralleled by coordinated changes in the expression of Enpp1 and adipocyte-maturation key genes.


GALNT2 is a novel modulator of adipogenesis and related cellular phenotypes, thus becoming a potential target for tackling the obesity epidemics and its devastating sequelae.

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  1. 1.

    WHO. Noncommunicable Diseases, Progress Monitor 2017. WHO, 72nd session of the UN General Assembly; 2017.

  2. 2.

    Reaven GM. Role of insulin resistance in human disease. Diabetes. 1988;37:1595–607.

  3. 3.

    Czech MP, Tencerova M, Pedersen DJ, Aouadi M. Insulin signalling mechanisms for triacylglycerol storage. Diabetologia. 2013;56:949–64.

  4. 4.

    Swinburn BA, Nyomba BL, Saad MF, Zurlo F, Raz I, Knowler WC, et al. Insulin resistance associated with lower rates of weight gain in Pima Indians. J Clin Invest. 1991;88:168–73.

  5. 5.

    Yki-Jarvinen H. Thiazolidinediones. N Engl J Med. 2004;351:1106–18.

  6. 6.

    White T, Bennett EP, Takio K, Sorensen T, Bonding N, Clausen H. Purification and cDNA cloning of a human UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase. J Biol Chem. 1995;270:24156–65.

  7. 7.

    Schjoldager KT, Joshi HJ, Kong Y, Goth CK, King SL, Wandall HH, et al. Deconstruction of O-glycosylation—GalNAc-T isoforms direct distinct subsets of the O-glycoproteome. EMBO Rep. 2015;16:1713–22.

  8. 8.

    Kathiresan S, Willer CJ, Peloso GM, Demissie S, Musunuru K, Schadt EE, et al. Common variants at 30 loci contribute to polygenic dyslipidemia. Nat Genet. 2009;41:56–65.

  9. 9.

    Teslovich TM, Musunuru K, Smith AV, Edmondson AC, Stylianou IM, Koseki M, et al. Biological, clinical and population relevance of 95 loci for blood lipids. Nature. 2010;466:707–13.

  10. 10.

    Khetarpal SA, Schjoldager KT, Christoffersen C, Raghavan A, Edmondson AC, Reutter HM, et al. Loss of function of GALNT2 lowers high-density lipoproteins in humans, nonhuman primates, and rodents. Cell Metab. 2016;24:234–45.

  11. 11.

    Di Paola R, Marucci A, Trischitta V. GALNT2 effect on HDL-cholesterol and triglycerides levels in humans: evidence of pleiotropy? Nutr Metab Cardiovasc Dis. 2017;27:281–2.

  12. 12.

    Marucci A, Cozzolino F, Dimatteo C, Monti M, Pucci P, Trischitta V, et al. Role of GALNT2 in the modulation of ENPP1 expression, and insulin signaling and action. Biochimica et Biophysica Acta Mol Cell Res. 2013;1833:1388–95.

  13. 13.

    Lee YH, Nair S, Rousseau E, Allison DB, Page GP, Tataranni PA, et al. Microarray profiling of isolated abdominal subcutaneous adipocytes from obese vs non-obese Pima Indians: increased expression of inflammation-related genes. Diabetologia. 2005;48:1776–83.

  14. 14.

    Carlotti F, Bazuine M, Kekarainen T, Seppen J, Pognonec P, Maassen JA, et al. Lentiviral vectors efficiently transduce quiescent mature 3T3-L1 adipocytes. Mol Ther. 2004;9:209–17.

  15. 15.

    Graham FL, van der Eb AJ. A new technique for the assay of infectivity of human adenovirus 5 DNA. Virology. 1973;52:456–67.

  16. 16.

    Vandesompele J, De Preter K, Pattyn I, Poppe B, Van Roy N, De Paepe A, et al. Accurate normalization of real-time quantitative RT-PCR data by geometric averaging of multiple internal control genes. Genome Biol. 2002;3:34–1.

  17. 17.

    Rosen ED, MacDougald OA. Adipocyte differentiation from the inside out. Nat Rev Mol Cell Biol. 2006;7:885–96.

  18. 18.

    Czech MP. Cellular basis of insulin insensitivity in large rat adipocytes. J Clin Invest. 1976;57:1523–32.

  19. 19.

    Arner E, Westermark PO, Spalding KL, Britton T, Ryden M, Frisen J, et al. Adipocyte turnover: relevance to human adipose tissue morphology. Diabetes. 2010;59:105–9.

  20. 20.

    Guilherme A, Virbasius JV, Puri V, Czech MP. Adipocyte dysfunctions linking obesity to insulin resistance and type 2 diabetes. Nat Rev Mol Cell Biol. 2008;9:367–77.

  21. 21.

    Olefsky JM. Mechanisms of decreased insulin responsiveness of large adipocytes. Endocrinology. 1977;100:1169–77.

  22. 22.

    Shao D, Lazar MA. Peroxisome proliferator activated receptor gamma, CCAAT/enhancer-binding protein alpha, and cell cycle status regulate the commitment to adipocyte differentiation. J Biol Chem. 1997;272:21473–8.

  23. 23.

    Maddux BA, Sbraccia P, Kumakura S, Sasson S, Youngren J, Fisher A, et al. Membrane glycoprotein PC-1 and insulin resistance in non-insulin-dependent diabetes mellitus. Nature. 1995;373:448–51.

  24. 24.

    Abate N, Chandalia M, Di Paola R, Foster DW, Grundy SM, Trischitta V. Mechanisms of disease: Ectonucleotide pyrophosphatase phosphodiesterase 1 as a “gatekeeper” of insulin receptors. Nat Clin Pract Endocrinol Metab. 2006;2:694–701.

  25. 25.

    Di Paola R, Caporarello N, Marucci A, Dimatteo C, Iadicicco C, Del Guerra S, et al. ENPP1 affects insulin action and secretion: evidences from in vitro studies. PLoS ONE. 2011;6:e19462.

  26. 26.

    Marucci A, Miscio G, Padovano L, Boonyasrisawat W, Doria A, Trischitta V, et al. A functional variant in the gene 3’ untranslated region regulates HSP70 expression and is a potential candidate for insulin resistance-related abnormalities. J Intern Med Suppl. 2010;267:237–40.

  27. 27.

    Kern PA, Saghizadeh M, Ong JM, Bosch RJ, Deem R, Simsolo RB. The expression of tumor necrosis factor in human adipose tissue. Regulation by obesity, weight loss, and relationship to lipoprotein lipase. J Clin Invest. 1995;95:2111–9.

  28. 28.

    Uysal KT, Wiesbrock SM, Marino MW, Hotamisligil GS. Protection from obesity-induced insulin resistance in mice lacking TNF-alpha function. Nature. 1997;389:610–4.

  29. 29.

    Pal A, Barber TM, Van de Bunt M, Rudge SA, Zhang Q, Lachlan KL, et al. PTEN mutations as a cause of constitutive insulin sensitivity and obesity. N Engl J Med. 2012;367:1002–11.

  30. 30.

    Schwartz DR, Lazar MA. Human resistin: found in translation from mouse to man. Trends Endocrinol Metab. 2011;22:259–65.

  31. 31.

    Hage Hassan R, Pacheco de Sousa AC, Mahfouz R, Hainault I, Blachnio-Zabielska A, Bourron O, et al. Sustained action of ceramide on the insulin signaling pathway in muscle cells: implication of the double-stranded Rna-activated protein kinase. J Biol Chem. 2016;291:3019–29.

  32. 32.

    Hong Y-H, Hishikawa D, Miyahara H, Tsuzuki H, Nishimura Y, Gotoh C, et al. Up-regulation of adipogenin, an adipocyte plasma transmembrane protein, during adipogenesis. Mol Cell Biochem. 2005;276:133–41.

  33. 33.

    Dahlman I, Nilsson M, Jiao H, Hoffstedt J, Lindgren CM, Humphreys K, et al. Liver X receptor gene polymorphisms and adipose tissue expression levels in obesity. Pharmacogenet Genom. 2006;16:881–9.

  34. 34.

    Kim S, Ahn C, Bong N, Choe S, Lee DK. Biphasic effects of FGF2 on adipogenesis. PLoS ONE. 2015;10:1–12.

  35. 35.

    Poletto AC, David-Silva A, Yamamoto APDM, Machado UF, Furuya DT. Reduced Slc2a4/GLUT4 expression in subcutaneous adipose tissue of monosodium glutamate obese mice is recovered after atorvastatin treatment. Diabetol Metab Syndr. 2015;7:1–6.

  36. 36.

    Lee MJ, Yang RZ, Karastergiou K, Smith SR, Chang JR, Gong DW, et al. Low expression of the GILZ may contribute to adipose inflammation and altered adipokine production in human obesity. J Lipid Res. 2016;57:1256–63.

  37. 37.

    Bazhan NM, Baklanov AV, Piskunova JV, Kazantseva AJ, Makarova EN. Expression of genes involved in carbohydrate-lipid metabolism in muscle and fat tissues in the initial stage of adult-age obesity in fed and fasted mice. Physiol Rep. 2017;5:1–10.

  38. 38.

    Jonas MI, Kurylowicz A, Bartoszewicz Z, Lisik W, Jonas M, Domienik-Karlowicz J, et al. Adiponectin/resistin interplay in serum and in adipose tissue of obese and normal-weight individuals. Diabetol Metab Syndr. 2017;9:1–9.

  39. 39.

    Nascimento EBM, Sparks LM, Divoux A, van Gisbergen MW, Broeders EPM, Jörgensen JA, et al. Genetic markers of brown adipose tissue identity and in vitro brown adipose tissue activity in humans. Obesity. 2017;26:135–40.

  40. 40.

    Bennett EP, Mandel U, Clausen H, Gerken TA, Fritz TA, Tabak LA. Control of mucin-type O-glycosylation: a classification of the polypeptide GalNAc-transferase gene family. Glycobiology. 2012;22:736–56.

  41. 41.

    Wollaston-Hayden EE, Harris RBS, Liu B, Bridger R, Xu Y, Wells L. Global O-GlcNAc levels modulate transcription of the adipocyte secretome during chronic insulin resistance. Front Endocrinol. 2015;5:223.

  42. 42.

    Czech MP, Aouadi M, Tesz GJ. RNAi-based therapeutic strategies for metabolic disease. Nat Rev Endocrinol. 2011;7:473–84.

  43. 43.

    Fountas A, Diamantopoulos LN, Tsatsoulis A. Tyrosine kinase inhibitors and diabetes: a novel treatment paradigm? Trends Endocrinol Metab. 2015;26:643–56.

  44. 44.

    Ishihara K, Takahashi I, Tsuchiya Y, Hasegawa M, Kamemura K. Characteristic increase in nucleocytoplasmic protein glycosylation by O-GlcNAc in 3T3-L1 adipocyte differentiation. Biochem Biophys Res Commun. 2010;398:489–94.

  45. 45.

    Agostini M, Schoenmakers E, Beig J, Fairall L, Szatmari I, Rajanayagam O, et al. A pharmacogenetic approach to the treatment of patients with PPARG mutations. Diabetes. 2018;67:1086–92.

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This work was supported by the Italian Ministry of Health Ricerca Corrente 2017-2019 (A.M., R.D.P., V.T.).

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Correspondence to Vincenzo Trischitta or Rosa Di Paola.

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