Integrative cellular ageing and inflammation

Role of protein oxidative modifications, maintenance and
thioredoxin system in ageing and arterial protection against oxidative stress.

Cellular senescence, oxidative stress and inflammation are playing a critical role in normal human ageing and in the progression of several age-related pathologies.

Indeed, cellular ageing has been associated with an increased production of reactive oxygen species and an impairment of cellular defenses against oxidant-mediated insults.

Moreover, ageing has also been viewed as a progressive collapse of defense and repair functions that leads to physiological frailty. These changes are associated with progressive degeneration of biological functions and increased susceptibility to diseases such as cardiovascular diseases. Thus for example, available evidences showed a decline with age of the thioredoxin-1 (Trx-1), a critical protein for the protection against oxidative stress and inflammation. This decline can be attributed, in part, to the cleavage of Trx-1 by 2 a-secretases resulting in the truncated protein, Trx-80 which has powerful pro-inflammatory and mitogenic effects leading to enhanced atherosclerosis in mice.

Our goals are to elucidate the role of protein oxidation as well as oxidized protein degradation and repair during cellular ageing ex vivo and in vitro and in situations of oxidative stress leading to accelerated ageing with relevant human cellular models. We will also investigate the effect of Trx-1 mimetic peptides on cell culture and on mouse model. The result will help to translate these findings into new therapies based on Trx-1 peptides.

Finally, the relationship between oxidative stress, protein homeostasis and circadian rhythmicity in relevant human cellular models will be investigated.

More...

Our team result of the fusion of the two previous groups of Bertrand Friguet and Mustapha Rouis to create a new team titled: “Integrative cellular ageing and inflammation” for the
2014-2018 period.

Our main goals are to elucidate the role of oxidative and related modifications of proteins as well as the implication of protein maintenance (e.g. oxidized
protein degradation and repair systems) in cellular ageing and in situations of oxidative stress with relevant human cellular models and to investigate the role of the ubiquitous anti-oxidant, anti-inflammatory and anti-apoptotic protein thioredoxin-1 (Trx-1) in arterial protection against oxidative stress and of its truncated pro-inflammatory form (Trx-80) in vascular cellular senescence and inflammation with human macrophages and transgenic mice overexpressing Trx-1 or Trx-80. Extensive investigation on the role of inflammasome NLRP3 in vascular diseases is also conducted.

Cellular ageing has been associated with an increased production of reactive oxygen species also referred as “oxidative stress” and the impairment of cellular defenses against oxidantmediated insults while inflammation, which is also promoting “oxidative stress”, has been recognized as a key component of ageing, also referred as “inflamm’ageing”, at the tissue and organ levels. Hence, cellular senescence, oxidative stress and inflammation are playing a critical role in normal ageing and in the progression of several age-related pathologies for humans, among which cardiovascular diseases that represent one of the main causes of death
in western countries.

Our research proposal is expected to bring fundamental knowledge on protein oxidative modifications and their role in ageing and in the progression of age-related diseases as well as to further develop new approaches for monitoring protein modification at the proteome level. It is also aimed at elucidating the role of Trx-1 in protection against cardiovascular disease-associated oxidative stress especially in pathological vessels remodeling during atherosclerosis and to translate these findings into new therapies based on
Trx-1 peptides.

Moreover, we study the role of inflammasome NLRP3 in vascular diseases as well as identified specific inhibitors to better control inflammasome NLRP3 activity, in
particular, and inflammation in general. The long term prospect is to define new therapeutic targets within these age-associated pathologies and possibly design and patent selective molecules.

Highlights

In the previous years, the Rouis’s group was focused on

  • the elucidation of the gene regulation of TRX-1 and TXNIP, its endogenous inhibitor, in human macrophages (Billiet et
    al, J Mol Biol 2008, 384: 564-76; J Cell Physiol 2008, 214:183-191);
  • the identification of REDD2 (Regulated in development and DNA damage response 2), a new gene mediated cellular Trx-1 impairment and oxidative-induced macrophage death enhancement (Jguirim- Souissi I et al, Free Rad Biol Med 2009, 46:1404-1410);
  • the identification of the role of human cathepsin L in macrophage autophagy and its potential important role in the development of atherosclerosis (Mahmood DF et al, J Biol Chem 2011, 286:28858-28866)
  • the elucidation of macrophage polarization into M2 anti-inflammatory phenotype with Trx-1 (El Hadri et al, Arterioscler Thromb Vasc Biol (2012);32:1445-52). The major focus of the Friguet's group has been to elucidate the role of oxidative and related modifications of proteins as well as protein maintenance systems in cellular ageing and in
    2 situations of oxidative stress.

Important recent findings include:

  • the demonstration that damaged protein accumulation is associated with a decline of proteasome activity in ageing and in certain oxidative stress situations;
  • the implication of the oxidized protein repair system methionine sulfoxide reductase in the protection against oxidative stress (Cabreiro F et al, J Biol Chem 2008, 283:16673-16681; Antioxidant Redox Signal 2009,11:215-225)
  • the characterization of the age-related impairment of the Lon protease and its role in oxidized mitochondrial proteins accumulation (Bayot et al, J Biol Chem 2010, 285:11445-11457);
  • the identification of specific protein targets that are increasingly modified during replicative senescence of human fibroblasts and upon oxidative stress for muscle progenitor cells (Ahmed EK et al, Aging Cell 2010, 9:252-272; Baraibar et al, Free Rad Biol Med 2011, 51:1522-1532).

Future directions

  • The elucidation of the role of oxidative and related modifications of proteins as well as protein maintenance (i.e. oxidized protein degradation and repair) during cellular ageing ex vivo and in vitro and in situations of oxidative stress leading to accelerated ageing with relevant human cellular models (cell lines and primary cells: e. g. human embryonic and dermal fibroblasts, myoblasts from healthy and muscular dystrophic patients).
  • The investigation of the role of the ubiquitous anti-oxidant and anti-inflammatory protein thioredoxin-1 (Trx-1) in arterial protection against oxidative stress and to investigate the role of its truncated pro-inflammatory form (Trx-80) in vascular cellular senescence and inflammation in relevant cell culture (e.g. endothelial cells, smooth muscle cells and macrophages) and in transgenic mice overexpressing Trx-1 or Trx-80. A better understanding of the role of Trx-1 in cardiovascular disease will help to translate these findings into new therapies based on Trx-1 peptides.
  • The investigation of the role of inflammasome NLRP3, a cytosolic platform of proteins involving in the maturation of pro-IL--IL-18, in vascular diseases is extensively studied in our team using various biological approaches (e.g. primary culture murine and human macrophages, Nlrp3.KO mice). In parallel, we also identifying specific inflammasome NLRP3 inhibitors and characterize them in vitro and in vivo.
  • The investigation of the relationship, between oxidative stress, protein homeostasis and circadian rhythmicity in relevant human cellular models (e. g. permanent cell lines, macrophages, smooth muscle cells) since circadian rhythmicity is impaired in senescent smooth muscle cell while certain antioxidant enzyme activities are exhibiting circadian rhythmicity and cardiovascular clinical events occur, in general, early in the morning.

Collaborations

  • Dr Anne Salvayre : Equipe10 "Athérosclérose et artériosclérose de greffe" INSERM / Université Paul Sabatier UMR 1048. Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Toulouse.
  • Prof. Mohamed-Naceur Slimane : Laboratoire de biochimie, Faculté de Médecine, Monastir, Tunisie.
  • Prof. Thomas Simmet : University of Ulm Institute of Pharmacology, Toxicology & Natural Products, Allemagne.
  • - Dr Alan Remaley: Lipoprotein Metabolism Laboratory. NIH, NHLBI, Bethesda, MD, USA.
  • Dr Anne-Laure Bulteau: Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, CNRS/UPPA, UMR5254, 64000 Pau, France.
  • Dr Gillian Butler-Browne & Dr Vincent Mouly: Institut de Myologie, UMRS INSERM U974, CNRS UMR 7215, CHU Pitié-Salpétrière, Sorbonne Universités, UPMC Univ Paris 06, Paris, France.
  • Dr Carine Nizard : LVMH Recherche, 185 avenue de Verdun, 45800 Saint-Jean-de-Braye, France.
  • Dr Adelina Rogowska-Wrzesinska : Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
  • Dr Tilman Grune : Department of Molecular Toxicology, German Institute of Human Nutrition, Nuthetal, Germany.
  • Dr Marco Sandri : Dulbecco Telethon Institute at Venetian Institute of Molecular Medicine, 35129 Padova, Italy.
  • Dr Eduardo Silva : Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Casilla 306, Correo 22, Santiago de Chile.
  • Dr Luke Szweda : Free Radical Biology and Aging Research Program Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America.