PIERRE BUFFET


Email: pierre.buffet@upmc.fr

Erythrocytes, Parasites and Pathogenesis

Free flow of erythrocytes in circulatory spaces is essential to the survival of vertebrates. Surface integrity of erythrocytes and their ability to deform are under permanent scrutiny, mainly by the spleen. Infection with Plasmodium falciparum induces an array of erythrocyte alterations leading to the retention of a proportion of parasitized erythrocytes in the microcirculation. Our goal is to better understand interactions between altered (eg, parasitized) erythrocytes and peculiar microcirculatory spaces devoid of endothelium in the spleen and the bone marrow. In malaria patients, these interactions contribute – before and after initiation of antimalarial therapy – to the control of parasite multiplication. Non-vascular spaces may also provide niches for parasite persistence. Our project will be developed following 2 axes:

Axis 1: Host sensing of erythrocytes in non-vascular circulatory spaces, parasite transmission, parasite persistence.

Specifically, we will (i) determine physiological thresholds for splenic retention of erythrocytes in humans and in animal models, (ii) develop a screening process to identify stiffening compounds that induce parasite retention in the spleen thereby blocking malaria transmission, and (iii) explore potential mechanisms of parasite persistence in the macrophage-rich environments of the spleen and the bone marrow.

 

Axis 2: Splenic parasite clearance in artemisinin-treated patients and artemisinin-resistant P. falciparum.

 

Based on a network established by the National Reference Center for malaria, we will implement the follow-up of French patients treated with artemisinins as a sentinel surveillance system to detect the spread of artemisinin-resistant P. falciparum to Africa. Through field studies in Africa and South-East Asia we will search for determinants of parasite clearance in artemisinin-treated patients. Not least, we will try to provide a physiologically relevant marker to detect artemisinin-resistant parasites in vitro.

Axis 3: Transfusion.

 With the support of the GR-Ex, we are currently optimizing our microsphiltration device for potential application to transfusion (rejuvenation of stored red blood cell concentrates).

Expertise

  1. Ektacytometer, polycarbonate erythrocyte filters.
  2. Fluorescence microscope with contrast phase Interference “Nomarsky”.
  3. Portable flow cytometer.
  4. Filtration of red blood cells through microsphere layers “microsphiltration” adapted to microplates for screening purposes.

 Main publications

  1. Buffet PA*, Gamain B*, Scheidig C, Baruch D, Smith JD, Hernandez-Rivas R, Pouvelle B, Oishi S, Fujii N, Fusai T, Parzy D, Miller LH, Gysin J, Scherf A. Plasmodium falciparum domain mediating adhesion to chondroitin sulfate A : a receptor for human placental infection. PNAS 1999; 96(22):12743-8. * Equal contributions
  2. Pouvelle B, Buffet PA, Lépolard C, Scherf A, Gysin J. Cytoadhesion of Plasmodium falciparum ring-stage-infected erythrocytes. Nature Medicine 2000;6(11):1264-68.
  3. Buffet PA, Milon G, Brousse V, Correas JM, Dousset B, Couvelard A,  Kianmanesh R, Farges O, Sauvanet S, Paye F, Ungeheuer MN, Ottone C, Khun H, Fiette L, Huerre M, Mercereau-Puijalon O, David PH. Ex-vivo perfusion of human spleens maintains clearing and processing functions. Blood 2006;107(9):3745-52.
  4.  Mamani-Matsuda M, Cosma A, Weller S, Faili A, Staib C, Garçon L, Hermine O, Adoue D, Fieschi C, Pers JO, Arakelyan N, Varet B, Sauvanet A, Berger A, Paye F, Andrieu JM, Michel M, Godeau B, Buffet P, Reynaud CA, and Weill JC. The human spleen is the main reservoir for life long memory B-cells Blood 2008;111(9):4653-9.
  5. Safeukui I, Correas J-M, Brousse V, Hirt D, Deplaine G, Mulé S, Lesurtel M, Goasguen N, Sauvanet A, Couvelard A, Kerneis S, Khun H, Vigan-Womas I, Ottone C, Molina TJ, Tréluyer JM, Mercereau-Puijalon O, Milon G, David PH, Buffet PA. Retention of Plasmodium falciparum ring-infected erythrocytes in the slow, open micro-circulation of the human spleen. Blood 2008;112:2520-28.
  6. Deplaine G, Safeukui I, Jeddi F, Lacoste F, Brousse V, Perrot S, Biligui S, Guillotte M,  Guitton C, Dokmak S, Aussilhou B, Sauvanet A, Couvelard A, Paye F, Thellier M, Mazier D, Milon G, Mohandas N, Mercereau-Puijalon O, David PH, Buffet PA. The sensing of poorly deformable red blood cells by the human spleen can be mimicked in vitro. Blood 2011;117(8):e88-95.
  7. Buffet PA, Safeukui I, Deplaine G, Brousse V, Prendki V, Thellier M, Turner G, Mercereau-Puijalon O. The pathogenesis of Plasmodium falciparum malaria in humans – Insights from spleen physiology. Blood 2011; 117(2):381-92.
  8. Tibúrcio M, Niang M, Deplaine G, Perrot S, Bischoff E, Ndour PA, Silvestrini F, Khattab A, Milon G, David PH, Hardeman M, Vernick KD, Sauerwein RW, Preiser PR, Mercereau-Puijalon O, Buffet P, Alano P, Lavazec C. A switch in infected erythrocyte deformability at the maturation and blood circulation of Plasmodium falciparum transmission stages. Blood 2012;119:e172-80.
  9. Farfour E, Charlotte F, Settegrana C, Miyara M, Buffet P. The extravascular compartment of the bone marrow: a niche for Plasmodium falciparum gametocyte maturation? Malaria Journal 2012;11:285.
  10. Safeukui I, Buffet PA, Deplaine G, Perrot S, Brousse V,  Ndour A, Nguyen MMercereau-Puijalon O,  David, PH Milon G,  Mohandas N. Quantitative assessment of sensing and sequestration of spherocytic erythrocytes by the human spleen. Blood 2012;120:424-30.