PhD My Andersson
Biological and related sciences, Health, Neurophysiology (synaptic physiology)
Health
Obesity, Diabetes, Immunology
In the Aouadi lab we investigate the mechanisms involved in the development of diabetes and liver disease in obese patients. In a healthy individual, the pancreas produces insulin, a hormone that regulates the amount of glucose in the blood after a meal. However, especially in obese patients, a condition termed insulin resistance occurs before overt diabetes. This is a condition in which the body cannot respond to insulin and therefore produces high levels of insulin to compensate. Despite this compensation, glucose is still not properly metabolised. For instance, the adipose tissue cannot properly take up glucose and store it in forms of fat, which results in lipid accumulation in other organs, such as the liver. Fat accumulation in the liver is toxic and can lead to a disease called Non-Alcoholic SteatoHepatitis (NASH).
NASH is projected to become the leading cause of liver related morbidity and mortality within 20 years, and the most common indication for liver transplantation in the next few years. In spite of its high prevalence and potential life-threatening effects, no approved treatments are currently available due to a lack of understanding of the pathogenesis. Epidemiological studies show that individuals with obesity and insulin resistance are at the greatest risk of developing NASH. However, the underlying mechanisms causing liver disease in individuals with metabolic disorders such as obesity and insulin resistance remain unknown.
Our lab has discovered that macrophages in the liver and adipose tissue are crucial in the development of metabolic dysfunction in these tissues independently of their inflammatory profile. Our lab takes advantage of sophisticated methods to investigate the multiple roles of macrophages and their function in obesity-associated metabolic dysfunction.
Women's Opportunity Award, Soroptimist, France, 2006
English, French
Tencerova M*, Aouadi M*, Vangala P, Nicoloro SM, Yawe JC, Cohen JL, Shen Y, Garcia-Menendez L, Pedersen DJ, Gallagher-Dorval K, Perugini RA, Gupta OT, Czech MP. “Activated Kupffer cells inhibit insulin sensitivity in obese mice”. FASEB J. 2015 Jul;29(7):2959-69. *Authors contributed equally to this work. . Citations: 5
Aouadi, M., Vangala, P., Yawe, J. C., Tencerova, M., Nicoloro, S. M., Cohen, J. L., Shen, Y. and Czech, M. P. “ Lipid storage by adipose tissue macrophages regulates systemic glucose tolerance”. Am J Physiol Endocrinol Metab. 2014 Aug 15;307(4):E374-83. Citations: 13
Amano, S. U., Cohen, J. L., Vangala, P., Tencerova, M., Nicoloro, S. M., Yawe, J. C., Shen, Y., Czech, M. P. and Aouadi, M. “Local proliferation of adipose tissue macrophages in obesity-associated inflammation”. Cell Metabolism. 2014 Jan;19(1):162-71. Citations: 107
Jourdan, T., Godlewski, G., Cinar, R., Bertola, A., Szanda, G., Liu, J., Tam, J., Han, T., Mukhopadhyay, B., Skarulis, M. C., Ju, C., Aouadi, M., Czech, M. P. and Kunos, G. “Endocannabinoid-activated Nlrp3 inflammasome in infiltrating macrophages mediates β-cell loss in type 2 diabetes”. Nat Med. 2013 Sep;19(9):1132-40. Citations: 95
Aouadi, M., Tencerova, M., Vangala, P., Yawe, J. C., Nicoloro, S. M., Amano, S. U., Cohen, J. L. and Czech, M. P. “ Gene silencing in adipose tissue macrophages regulates whole-body metabolism in obese mice”. PNAS. 2013 May;110(20):8278-83. Citations: 38
Guo, C. A., Kogan, S., Amano, S. U., Wang, M., Dagdeviren, S., Friedline, R. H., Aouadi, M., Kim, J. K. and Czech, M. P. “CD40 Deficiency in Mice Exacerbates Diet-induced Adipose Tissue Inflammation, Hepatic Steatosis and Insulin Resistance”. Am J Physiol Endocrinol Metab. 2013 Mar;304(9):E951-63. Citations: 17
Fitzgibbons, T. P., Kogan, S., Aouadi, M., Hendricks, G. M., Straubhaar, J. and Czech, M. P. “Similarity of mouse perivascular and brown adipose tissues and their resistance to diet-induced inflammation”. Am J Physiol Heart Circ Physiol. 2011 Oct;301(4):H1425-37. Citations: 58
Tesz, G. J. *, Aouadi, M. *, Prot, M., Nicoloro, S. M., Boutet, E., Amano, S. U., Goller, A., Wang, M., Guo, C. A., Salomon, W. E., Virbasius, J. V., Baum, R. A., O'Connor, M. J., Jr., Soto, E., Ostroff, G. R. and Czech, M. P.” Selective Targeting of siRNA to Phagocytic Cells by Glucan Particles Containing an Amphipathic Peptide ”. Biochemical Journal. 2011 Jun 1;436(2):351-62. *Authors contributed equally to this work. Citations: 32
Huang, W., Ghisletti, S., Saijo, K., Gandhi, M., Aouadi, M., Tesz, G. J., Zhang, D. X., Yao, J., Czech, M. P., Goode, B. L., Rosenfeld, M. G. and Glass, C. K. “Coronin 2A mediates actin-dependent de-repression of inflammatory response genes”. Nature. 2011 Feb 17;470(7334):414-8. Citations: 64
Aouadi, M., Tesz, G. J., Nicoloro, S. M., Wang, M., Chouinard, M., Soto, E., Ostroff, G. R. and Czech, M. P. “Orally delivered siRNA targeting macrophage MAP4K4 suppresses systemic inflammation”. Nature, 2009 Apr 30;458(7242):1180-4. Citations: 240
We have recently discovered that mice fed a high fat diet (HFD) become rapidly obese and insulin resistant independently of liver inflammation, which was thought to be an important driver in obesity-induced insulin resistance. On the other hand, depletion studies have shown that removing liver macrophages (LMs) prevents insulin resistance induced by obesity, suggesting an important role of LMs in the regulation of insulin sensitivity. Using RNAseq, we identified genes specifically expressed by liver macrophages, whose expression significantly increases with obesity and insulin resistance. We then took advantage of a powerful and unique tool, called glucan encapsulated RNAi particles (GeRP), that deliver siRNA and silence genes specifically in macrophages in vivo.
This technology is based on small interfering RNA (siRNA) encapsulated within glucan particles derived from baker’s yeast. By using intraperitoneal injections, we showed that GeRPs delivered siRNA and silenced genes specifically in macrophages in the adipose tissue of obese mice. However, by using intravenous administration, we showed that GeRPs delivered siRNA and silenced genes in LMs but not in hepatocytes or macrophages within other tissues.
Using this unique method, we found that silencing genes of interest specifically in LMs improves insulin sensitivity in obese mice. This project has so far confirmed that liver macrophages can play a role in the regulation of insulin sensitivity independantly of inflammation. This opened a new avenue towards the discovery of the multiple roles of immune cells other than only the inflammatory response.
Macrophages are able to modulate their properties upon contact with different cell types as well as extracellular matrix. Their intrinsic heterogeneity during differentiation is compounded by reciprocal interactions with neighbouring cells, including other macrophages. In many different tissues, macrophages can occupy different anatomical niches and perform specialized functions even within the same organ. Emerging data suggest that macrophages acquire specialized functions, which are tailored for assisting local homeostasis, within each particular organ.
We use scRNAseq, metabolomics, flow cytometry, CytOF and in situ transcriptomic to study the heterogeneity of resident macrophage in liver and adipose tissue in health and metabolic disease.
We aim at identifying dysregulated genes but also non-coding RNAs such as microRNAs, enhancer RNAs, and long non-coding RNAs which have recently emerged as important regulators of gene expression, and which expression have been associated with several diseases.
Using the Global Run-On sequencing (GRO-seq) to directly measure rates of nascent transcription genome-wide, we propose to identify all transcript, genes and non-coding RNAs dysregulated in LMs in obesity that could be involved in the development of insulin resistance.
We are especially interested in enhancers, which are regions of DNA important for the regulation of genes transcription, and can be transcribed as non-coding RNAs called enhancer-derived RNAs (eRNAs).
The eRNAs can regulate the expression of the nearby gene, and have also been shown to be superior markers for active enhancers because of their small size and high dynamic ranges.
The mining of the GRO-seq data for eRNAs transcription to map functional enhancers, combined with genome-wide de novo motif analysis performed at sites of eRNAs dysregulation in LMs from obese and insulin resistant mice compared to lean mice, will allow us to identify the transcription factor(s) that could be involved in gene dysregulation in LMs in obesity.
Member, Strategic Research Project Diabetes Network, Karolinska Institutet, since 2015
Member, Swedish Society of Medicine, since 2015
Member, Research Network “Liver Academy at Karolinska Institutet”, since 2015
Member, American Diabetes Association, 2012 – 2014
Review panel member, French National Research agency, France, 2015
Review panel member, Dutch Diabetes Research Foundation, Netherland, 2014
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Biological and related sciences, Health, Neurophysiology (synaptic physiology)
Health, Academic Medicine
Biological and related sciences, Health, Cell Biology, Cellular signaling, Cancer biology, Cancer therapy
Biological and related sciences, Health, Cell Biology, Cellular and Molecular Neuroscience, Vascular Biology, Tumour Biology