Torp 2018 MiPschool Tromso C3

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MiPsociety
Intracellular complement factor 3 in the heart – a link to metabolism?

Link: MitoEAGLE

Torp MK, Ranheim T, Heiestad C, Nilsson P, Schjalm C, Mollnes TE, Yndestad A, Stensloekken KO (2018)

Event: MiPschool Tromso-Bergen 2018

COST Action MitoEAGLE

The complement system has traditionally been investigated systemically. The proteins involved in complement activation are produced in the liver and are released into the circulation in order to eliminate invading pathogens [1]. However, recent discoveries show that the complement system can be activated intracellularly in T-cells and is linked to cell metabolism and survival through mTOR [2]. In this project, we investigate intracellular complement activation in the heart.

Isolated hearts of adult wildtype (WT) and intracellular component 3 knock-out (C3KO) C57BL/6 male mice were ex vivo retrogradely perfused at constant pressure (70 mmHg). Left ventricular pressure was monitored through a fluid-filled balloon placed in the left ventricle. The experimental set-up: 20 min stabilization, 35 min global ischemia, and 60 min reperfusion. Infarct size was measured with 1% TTC staining. Lactate dehydrogenase (LDH) release was measured from the collected coronary perfusates. mRNA and protein expression was measured with qPCR and western blotting.

After 35 min ischemia, C3KO hearts had significantly higher left ventricular end-diastolic pressure (LVEDP) compared to WT hearts. C3KO hearts also exhibited significant larger infarct size and LDH release compared to WT hearts. Additionally, in WT hearts subjected to ex vivo ischemia-reperfusion, we found an increase in C3 mRNA expression compared to WT hearts briefly flushed with PBS. We confirmed the presence of intracellular C3 in isolated cardiomyocytes, cardiac fibroblasts, and hearts subjected to ex vivo ischemia-reperfusion with western blotting, which was not present in the C3KO.

Intracellular C3 is present in cardiac cells and was shown to be protective in ex vivo ischemia-reperfusion injury. The role of intracellular C3 and its potential connection to mitochondria will be part of future experiments.


Bioblast editor: Beno M, Plangger M


Labels: MiParea: Genetic knockout;overexpression 

Stress:Ischemia-reperfusion  Organism: Mouse  Tissue;cell: Heart 




Event: C3, Oral 


Affiliations

Torp MK(1,3), Ranheim T(2,3), Heiestad C(1,3), Nilsson P, Schjalm C, Mollnes TE, Yndestad A, Stensloekken KO

  1. Dept Molecular Medicine, Univ Oslo
  2. Research Inst Internal Medicine, Oslo Univ Hospital Rikshospitalet; Norway
  3. Center Heart Failure Research
  4. Dept Immunology; Univ Oslo, Norway

References

  1. Merle NS, Noe R, Halbwachs-Mecarelli L, Fremeaux-Bacchi V, Roumenina LT (2015) Complement System Part II: Role in Immunity. Front Immunol 6:257.
  2. Liszewski MK, Kolev M, Le Friec G, Leung M, Bertram PG, Fara AF, Subias M, Pickering MC, Drouet C, Meri S, Arstila TP, Pekkarinen PT, Ma M, Cope A, Reinheckel T, Rodriguez de Cordoba S, Afzali B, Atkinson JP, Kemper C (2013) Intracellular complement activation sustains T cell homeostasis and mediates effector differentiation. Immunity 39:1143-57.