Limits...
Mice with targeted disruption of p8 gene show increased sensitivity to lipopolysaccharide and DNA microarray analysis of livers reveals an aberrant gene expression response.

Vasseur S, Hoffmeister A, Garcia-Montero A, Barthet M, Saint-Michel L, Berthézène P, Fiedler F, Closa D, Dagorn JC, Iovanna JL - BMC Gastroenterol (2003)

Bottom Line: Hence, p8 could be a mediator of LPS-associated effects or, on the contrary, p8 expression may be part of the protective mechanism of the tissues in response to LPS.Liver was chosen as model organ to monitor alterations in gene expression.The large number of genes showing abnormal regulation after LPS suggests that p8 is an important regulatory factor involved in many cellular defence pathways.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France. vasseur@marseille.inserm.fr

ABSTRACT

Background: p8 is a DNA-binding protein induced in many tissues in response to LPS treatment. Hence, p8 could be a mediator of LPS-associated effects or, on the contrary, p8 expression may be part of the protective mechanism of the tissues in response to LPS. Finally, p8 expression in response to LPS could also be a simple epiphenomenon.

Methods: To investigate the role of p8 in vivo, we generated p8-deficient mice by gene targeting. Because p8 is a stress protein, we analyzed the response of p8-/- mice to a systemic stress induced by LPS injection. Liver was chosen as model organ to monitor alterations in gene expression.

Results: LPS resulted in higher serum TNF-alpha concentration and higher mortality rate in p8-deficient mice than in wild-type. Also, liver and pancreas, but not lung, from p8-/- mice showed increased amounts of MPO and HPO. To gain insight into the molecular bases of such susceptibility, we used high density DNA microarrays consisting of ~6000 genes and ESTs to compare gene regulation in response to LPS in p8+/+ and p8-/- livers. In wild-type, 105 genes and 73 ESTs were up-regulated and 232 genes and 138 ESTs down-regulated. By contrast, 212 genes and 125 ESTs were found up-regulated and 90 genes and 85 ESTs down regulated in p8-/- mice. Among them, only 93 (51 induced and 42 repressed) corresponded to the wild-type pattern, demonstrating that p8 deficiency hinders the normal response to LPS, which may account for the increased sensitivity of p8-/-mice to the endotoxin.

Conclusions: The large number of genes showing abnormal regulation after LPS suggests that p8 is an important regulatory factor involved in many cellular defence pathways.

Show MeSH
Wild-type and p8-deficient mice were injected intraperitoneally with 70 mg/kg LPS (Salmonella thyphosa), and Myeloperoxidase (MPO) activity and Hydroperoxide (HPO) concentration were measured in lung after 6, 12, 18 and 24 hours. Errors bars represent the standard deviation (n = 7).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC212298&req=5

Figure 3: Wild-type and p8-deficient mice were injected intraperitoneally with 70 mg/kg LPS (Salmonella thyphosa), and Myeloperoxidase (MPO) activity and Hydroperoxide (HPO) concentration were measured in lung after 6, 12, 18 and 24 hours. Errors bars represent the standard deviation (n = 7).

Mentions: LPS is known to induce a systemic inflammatory syndrome characterized by strong leucocytic infiltration and free radical production which may be lethal [10]. To investigate the role of p8 expression during LPS treatment we monitored MPO activity, as an indicator of tissue infiltration, and HPO concentration as an indicator of free radical production, known to correlate with the intensity of lesions. In control mice, liver, lung and pancreas showed increased MPO activity and HPO concentration after LPS injection, as expected (Figures 3, 4 and 5). In p8-/- mouse lungs, the kinetics of changes in MPO activity and HPO were the same as in wild-type mice (Figure 3). They were however very different in pancreas and liver, showing that p8 influence could vary among tissues. In liver from control mice, MPO activity increased sharply to a maximum already reached 6 hours after LPS injection, then dropped by 65% in the next 6 hours and decreased more progressively thereafter (Figure 4), indicating that liver recruited leucocytes for transient infiltration. In liver from p8-deficient mice, MPO activity increases progressively with a maximum at 18 hours suggesting that the mechanism of leucocyte recruitment was either altered or different from wild-type. Contrary to MPO activity, HPO production was similar in p8+/+ and p8-/- mouse livers. This is not surprising since HPO is produced by Kupffer cells [11] which are specialized macrophages residing in the liver. In pancreas from control mice, changes in MPO and HPO followed the same pattern, i.e. transient increase with maximum 12 hours after LPS injection followed by decrease towards control values. In p8-deficient mice, both MPO activity and HPO concentration remained elevated after 12 hours (Figure 5) underscoring the role of p8 in the regulation of infiltration and free radical production. Taken together, these results suggest that p8 contributes to the tissue response to LPS, such response being different in pancreas, liver and lung.


Mice with targeted disruption of p8 gene show increased sensitivity to lipopolysaccharide and DNA microarray analysis of livers reveals an aberrant gene expression response.

Vasseur S, Hoffmeister A, Garcia-Montero A, Barthet M, Saint-Michel L, Berthézène P, Fiedler F, Closa D, Dagorn JC, Iovanna JL - BMC Gastroenterol (2003)

Wild-type and p8-deficient mice were injected intraperitoneally with 70 mg/kg LPS (Salmonella thyphosa), and Myeloperoxidase (MPO) activity and Hydroperoxide (HPO) concentration were measured in lung after 6, 12, 18 and 24 hours. Errors bars represent the standard deviation (n = 7).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC212298&req=5

Figure 3: Wild-type and p8-deficient mice were injected intraperitoneally with 70 mg/kg LPS (Salmonella thyphosa), and Myeloperoxidase (MPO) activity and Hydroperoxide (HPO) concentration were measured in lung after 6, 12, 18 and 24 hours. Errors bars represent the standard deviation (n = 7).
Mentions: LPS is known to induce a systemic inflammatory syndrome characterized by strong leucocytic infiltration and free radical production which may be lethal [10]. To investigate the role of p8 expression during LPS treatment we monitored MPO activity, as an indicator of tissue infiltration, and HPO concentration as an indicator of free radical production, known to correlate with the intensity of lesions. In control mice, liver, lung and pancreas showed increased MPO activity and HPO concentration after LPS injection, as expected (Figures 3, 4 and 5). In p8-/- mouse lungs, the kinetics of changes in MPO activity and HPO were the same as in wild-type mice (Figure 3). They were however very different in pancreas and liver, showing that p8 influence could vary among tissues. In liver from control mice, MPO activity increased sharply to a maximum already reached 6 hours after LPS injection, then dropped by 65% in the next 6 hours and decreased more progressively thereafter (Figure 4), indicating that liver recruited leucocytes for transient infiltration. In liver from p8-deficient mice, MPO activity increases progressively with a maximum at 18 hours suggesting that the mechanism of leucocyte recruitment was either altered or different from wild-type. Contrary to MPO activity, HPO production was similar in p8+/+ and p8-/- mouse livers. This is not surprising since HPO is produced by Kupffer cells [11] which are specialized macrophages residing in the liver. In pancreas from control mice, changes in MPO and HPO followed the same pattern, i.e. transient increase with maximum 12 hours after LPS injection followed by decrease towards control values. In p8-deficient mice, both MPO activity and HPO concentration remained elevated after 12 hours (Figure 5) underscoring the role of p8 in the regulation of infiltration and free radical production. Taken together, these results suggest that p8 contributes to the tissue response to LPS, such response being different in pancreas, liver and lung.

Bottom Line: Hence, p8 could be a mediator of LPS-associated effects or, on the contrary, p8 expression may be part of the protective mechanism of the tissues in response to LPS.Liver was chosen as model organ to monitor alterations in gene expression.The large number of genes showing abnormal regulation after LPS suggests that p8 is an important regulatory factor involved in many cellular defence pathways.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France. vasseur@marseille.inserm.fr

ABSTRACT

Background: p8 is a DNA-binding protein induced in many tissues in response to LPS treatment. Hence, p8 could be a mediator of LPS-associated effects or, on the contrary, p8 expression may be part of the protective mechanism of the tissues in response to LPS. Finally, p8 expression in response to LPS could also be a simple epiphenomenon.

Methods: To investigate the role of p8 in vivo, we generated p8-deficient mice by gene targeting. Because p8 is a stress protein, we analyzed the response of p8-/- mice to a systemic stress induced by LPS injection. Liver was chosen as model organ to monitor alterations in gene expression.

Results: LPS resulted in higher serum TNF-alpha concentration and higher mortality rate in p8-deficient mice than in wild-type. Also, liver and pancreas, but not lung, from p8-/- mice showed increased amounts of MPO and HPO. To gain insight into the molecular bases of such susceptibility, we used high density DNA microarrays consisting of ~6000 genes and ESTs to compare gene regulation in response to LPS in p8+/+ and p8-/- livers. In wild-type, 105 genes and 73 ESTs were up-regulated and 232 genes and 138 ESTs down-regulated. By contrast, 212 genes and 125 ESTs were found up-regulated and 90 genes and 85 ESTs down regulated in p8-/- mice. Among them, only 93 (51 induced and 42 repressed) corresponded to the wild-type pattern, demonstrating that p8 deficiency hinders the normal response to LPS, which may account for the increased sensitivity of p8-/-mice to the endotoxin.

Conclusions: The large number of genes showing abnormal regulation after LPS suggests that p8 is an important regulatory factor involved in many cellular defence pathways.

Show MeSH