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The complement anaphylatoxin C5a induces apoptosis in adrenomedullary cells during experimental sepsis.

Flierl MA, Rittirsch D, Chen AJ, Nadeau BA, Day DE, Sarma JV, Huber-Lang MS, Ward PA - PLoS ONE (2008)

Bottom Line: These effects could be reversed by dual-blockade of the C5a receptors, C5aR and C5L2.PC12 cell production of norepinephrine and dopamine was significantly blunted following exposure to recombinant rat C5a in a time-dependent and dose-dependent manner.Collectively, we describe a C5a-dependent induction of apoptotic events in cells of adrenal medulla in vivo and pheochromocytoma PC12 cells in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.

ABSTRACT
Sepsis remains a poorly understood, enigmatic disease. One of the cascades crucially involved in its pathogenesis is the complement system. Especially the anaphylatoxin C5a has been shown to have numerous harmful effects during sepsis. We have investigated the impact of high levels of C5a on the adrenal medulla following cecal ligation and puncture (CLP)-induced sepsis in rats as well as the role of C5a on catecholamine production from pheochromocytoma-derived PC12 cells. There was significant apoptosis of adrenal medulla cells in rats 24 hrs after CLP, as assessed by the TUNEL technique. These effects could be reversed by dual-blockade of the C5a receptors, C5aR and C5L2. When rats were subjected to CLP, levels of C5a and norepinephrine were found to be antipodal as a function of time. PC12 cell production of norepinephrine and dopamine was significantly blunted following exposure to recombinant rat C5a in a time-dependent and dose-dependent manner. This impaired production could be related to C5a-induced initiation of apoptosis as defined by binding of Annexin V and Propidium Iodine to PC12 cells. Collectively, we describe a C5a-dependent induction of apoptotic events in cells of adrenal medulla in vivo and pheochromocytoma PC12 cells in vitro. These data suggest that experimental sepsis induces apoptosis of adrenomedullary cells, which are responsible for the bulk of endogenous catecholamines. Septic shock may be linked to these events. Since blockade of both C5a receptors virtually abolished adrenomedullary apoptosis in vivo, C5aR and C5L2 become promising targets with implications on future complement-blocking strategies in the clinical setting of sepsis.

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Antipodal levels of C5a and norepinephrine following CLP.Animals were subjected to CLP and plasma was obtained 0–48 hrs after initiation of experimental sepsis. (A) Plasma levels of C5a as a function of time following CLP. (B) Norepinephrine concentrations in plasma 0–48 hrs after CLP. All bars are presented as mean±s.e.m. For each bar n = 4–10.
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pone-0002560-g002: Antipodal levels of C5a and norepinephrine following CLP.Animals were subjected to CLP and plasma was obtained 0–48 hrs after initiation of experimental sepsis. (A) Plasma levels of C5a as a function of time following CLP. (B) Norepinephrine concentrations in plasma 0–48 hrs after CLP. All bars are presented as mean±s.e.m. For each bar n = 4–10.

Mentions: Rats were subjected to cecal ligation and puncture (CLP)-induced sepsis, as previously described [15]. Plasma samples were obtained 0–48 hrs after CLP and analyzed for C5a and norepinephrine levels by ELISA. C5a levels were significantly elevated 24 hrs after initiation of experimental sepsis and peaked at 48 hrs (Figure 2A). In sharp contrast, there was a peak of plasma norepinephrine 6 hrs after initiation of CLP. Norepinephrine levels then fell below negative control levels 24 hrs and 48 hrs after CLP when compared to negative control levels (Figure 2B).


The complement anaphylatoxin C5a induces apoptosis in adrenomedullary cells during experimental sepsis.

Flierl MA, Rittirsch D, Chen AJ, Nadeau BA, Day DE, Sarma JV, Huber-Lang MS, Ward PA - PLoS ONE (2008)

Antipodal levels of C5a and norepinephrine following CLP.Animals were subjected to CLP and plasma was obtained 0–48 hrs after initiation of experimental sepsis. (A) Plasma levels of C5a as a function of time following CLP. (B) Norepinephrine concentrations in plasma 0–48 hrs after CLP. All bars are presented as mean±s.e.m. For each bar n = 4–10.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2481299&req=5

pone-0002560-g002: Antipodal levels of C5a and norepinephrine following CLP.Animals were subjected to CLP and plasma was obtained 0–48 hrs after initiation of experimental sepsis. (A) Plasma levels of C5a as a function of time following CLP. (B) Norepinephrine concentrations in plasma 0–48 hrs after CLP. All bars are presented as mean±s.e.m. For each bar n = 4–10.
Mentions: Rats were subjected to cecal ligation and puncture (CLP)-induced sepsis, as previously described [15]. Plasma samples were obtained 0–48 hrs after CLP and analyzed for C5a and norepinephrine levels by ELISA. C5a levels were significantly elevated 24 hrs after initiation of experimental sepsis and peaked at 48 hrs (Figure 2A). In sharp contrast, there was a peak of plasma norepinephrine 6 hrs after initiation of CLP. Norepinephrine levels then fell below negative control levels 24 hrs and 48 hrs after CLP when compared to negative control levels (Figure 2B).

Bottom Line: These effects could be reversed by dual-blockade of the C5a receptors, C5aR and C5L2.PC12 cell production of norepinephrine and dopamine was significantly blunted following exposure to recombinant rat C5a in a time-dependent and dose-dependent manner.Collectively, we describe a C5a-dependent induction of apoptotic events in cells of adrenal medulla in vivo and pheochromocytoma PC12 cells in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.

ABSTRACT
Sepsis remains a poorly understood, enigmatic disease. One of the cascades crucially involved in its pathogenesis is the complement system. Especially the anaphylatoxin C5a has been shown to have numerous harmful effects during sepsis. We have investigated the impact of high levels of C5a on the adrenal medulla following cecal ligation and puncture (CLP)-induced sepsis in rats as well as the role of C5a on catecholamine production from pheochromocytoma-derived PC12 cells. There was significant apoptosis of adrenal medulla cells in rats 24 hrs after CLP, as assessed by the TUNEL technique. These effects could be reversed by dual-blockade of the C5a receptors, C5aR and C5L2. When rats were subjected to CLP, levels of C5a and norepinephrine were found to be antipodal as a function of time. PC12 cell production of norepinephrine and dopamine was significantly blunted following exposure to recombinant rat C5a in a time-dependent and dose-dependent manner. This impaired production could be related to C5a-induced initiation of apoptosis as defined by binding of Annexin V and Propidium Iodine to PC12 cells. Collectively, we describe a C5a-dependent induction of apoptotic events in cells of adrenal medulla in vivo and pheochromocytoma PC12 cells in vitro. These data suggest that experimental sepsis induces apoptosis of adrenomedullary cells, which are responsible for the bulk of endogenous catecholamines. Septic shock may be linked to these events. Since blockade of both C5a receptors virtually abolished adrenomedullary apoptosis in vivo, C5aR and C5L2 become promising targets with implications on future complement-blocking strategies in the clinical setting of sepsis.

Show MeSH
Related in: MedlinePlus