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Experimental Malaria in Pregnancy Induces Neurocognitive Injury in Uninfected Offspring via a C5a-C5a Receptor Dependent Pathway.

McDonald CR, Cahill LS, Ho KT, Yang J, Kim H, Silver KL, Ward PA, Mount HT, Liles WC, Sled JG, Kain KC - PLoS Pathog. (2015)

Bottom Line: The in utero environment profoundly impacts childhood neurodevelopment and behaviour.These deficits were associated with reduced regional brain levels of major biogenic amines and BDNF that were rescued by disruption of C5a-C5aR signaling using genetic and functional approaches.Our results demonstrate that experimental MIP induces neurocognitive deficits in offspring and suggest novel targets for intervention.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.

ABSTRACT
The in utero environment profoundly impacts childhood neurodevelopment and behaviour. A substantial proportion of pregnancies in Africa are at risk of malaria in pregnancy (MIP) however the impact of in utero exposure to MIP on fetal neurodevelopment is unknown. Complement activation, in particular C5a, may contribute to neuropathology and adverse outcomes during MIP. We used an experimental model of MIP and standardized neurocognitive testing, MRI, micro-CT and HPLC analysis of neurotransmitter levels, to test the hypothesis that in utero exposure to malaria alters neurodevelopment through a C5a-C5aR dependent pathway. We show that malaria-exposed offspring have persistent neurocognitive deficits in memory and affective-like behaviour compared to unexposed controls. These deficits were associated with reduced regional brain levels of major biogenic amines and BDNF that were rescued by disruption of C5a-C5aR signaling using genetic and functional approaches. Our results demonstrate that experimental MIP induces neurocognitive deficits in offspring and suggest novel targets for intervention.

No MeSH data available.


Related in: MedlinePlus

In utero exposure to EMIP induces a cognitive phenotype in offspring that is rescued by genetic and pharmacological blockade of C5a-C5a receptor signaling.(a) Maternal parasitaemia (day one to seven post infection) expressed as percent of infected red blood cells (iRBCs) per total red blood cells counted in wild-type (n = 5) and C5ar-/- dams (n = 5). (b) Weight from one to six weeks of age in wild-type malaria unexposed (n = 14) and wild-type malaria exposed offspring (n = 13), C5ar-/- malaria unexposed (n = 13) and C5ar-/- malaria exposed (n = 14) offspring. (c) Testing Performance (preference ratio) and (d) total exploration time of wild-type unexposed (WT UE, n = 14), wild-type malaria exposed (WT EX, n = 13), C5a receptor knockout unexposed (C5ar-/- UE, n = 13) and C5ar-/- malaria exposed (C5ar-/- EX, n = 14) offspring in the NOR test (P > 0.05). (e) Performance of WT UE (n = 15), WT EX (n = 15), C5ar-/- UE (n = 13) and C5ar-/- EX (n = 15) offspring in the TST test. (f) Testing Performance (preference ratio) and (g) total exploration time of wild-type unexposed (WT UE, n = 11), wild-type malaria exposed (WT EX, n = 12), C5a receptor knockout unexposed (C5ar-/- UE, n = 13) and C5ar-/- malaria exposed (C5ar-/- EX, n = 9) offspring tested at 20 weeks of age in the NOR test. (h) Performance of WT UE (n = 12), WT EX (n = 11), C5ar-/- UE (n = 12) and C5ar-/- EX (n = 10) offspring tested at 20 weeks of age in the TST test. (i) Testing Performance (preference ratio) and (j) total exploration time of UE offspring (n = 11), EX offspring (n = 11), EX offspring of control rabbit antisera treated dams (R-EX, n = 12) and EX offspring of C5a antisera treated dams (αC5a-EX, n = 12) offspring in the NOR test (P > 0.05 for total exploration time). (k) Performance of UE (n = 11), EX (n = 12), R-EX (n = 10) and αC5a EX (n = 12) offspring in the TST test. *P < 0.05, **P < 0.01, ***P < 0.005; one-way ANOVA and post-test. Data are presented as mean +/- SD.
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ppat.1005140.g005: In utero exposure to EMIP induces a cognitive phenotype in offspring that is rescued by genetic and pharmacological blockade of C5a-C5a receptor signaling.(a) Maternal parasitaemia (day one to seven post infection) expressed as percent of infected red blood cells (iRBCs) per total red blood cells counted in wild-type (n = 5) and C5ar-/- dams (n = 5). (b) Weight from one to six weeks of age in wild-type malaria unexposed (n = 14) and wild-type malaria exposed offspring (n = 13), C5ar-/- malaria unexposed (n = 13) and C5ar-/- malaria exposed (n = 14) offspring. (c) Testing Performance (preference ratio) and (d) total exploration time of wild-type unexposed (WT UE, n = 14), wild-type malaria exposed (WT EX, n = 13), C5a receptor knockout unexposed (C5ar-/- UE, n = 13) and C5ar-/- malaria exposed (C5ar-/- EX, n = 14) offspring in the NOR test (P > 0.05). (e) Performance of WT UE (n = 15), WT EX (n = 15), C5ar-/- UE (n = 13) and C5ar-/- EX (n = 15) offspring in the TST test. (f) Testing Performance (preference ratio) and (g) total exploration time of wild-type unexposed (WT UE, n = 11), wild-type malaria exposed (WT EX, n = 12), C5a receptor knockout unexposed (C5ar-/- UE, n = 13) and C5ar-/- malaria exposed (C5ar-/- EX, n = 9) offspring tested at 20 weeks of age in the NOR test. (h) Performance of WT UE (n = 12), WT EX (n = 11), C5ar-/- UE (n = 12) and C5ar-/- EX (n = 10) offspring tested at 20 weeks of age in the TST test. (i) Testing Performance (preference ratio) and (j) total exploration time of UE offspring (n = 11), EX offspring (n = 11), EX offspring of control rabbit antisera treated dams (R-EX, n = 12) and EX offspring of C5a antisera treated dams (αC5a-EX, n = 12) offspring in the NOR test (P > 0.05 for total exploration time). (k) Performance of UE (n = 11), EX (n = 12), R-EX (n = 10) and αC5a EX (n = 12) offspring in the TST test. *P < 0.05, **P < 0.01, ***P < 0.005; one-way ANOVA and post-test. Data are presented as mean +/- SD.

Mentions: LBW, as a result of preterm birth or FGR, is known to be associated with impaired neurocognitive development [26,27]. Since MIP may cause LBW, these infants would be expected to experience an increased risk of neurocognitive impairment; however the majority of fetuses exposed to malaria in utero do not develop LBW. Therefore, in order to avoid LBW as a confounder and isolate the effects of malaria exposure alone on offspring neurodevelopment, we reduced the inoculum given to dams in a validated model of EMIP [28] from 106 to 105 PEs. This inoculum was associated with the presence of parasitized erythrocytes in the placenta and localized inflammation in the placenta (S1 Fig and S2 Fig). However the 105 inoculum was associated with lower maternal peripheral parasitemia (Fig 1A) and less marked placental pathology than that previously reported with a dose of 106 PEs [28]. This modification eliminated the LBW phenotype in this model and resulted in equivalent birth weights (from 1 to 20 weeks of age) in control pups compared to offspring exposed in utero to EMIP (Figs 1b, 5b and S3 Fig, S4 Fig and S5 Fig). No significant differences were observed in the length of gestation or litter size in this lower inoculum EMIP model (S1 Table). Placentas from malaria-infected litters (wild-type and C5ar-/-) showed placental inflammation as indicated by increased expression of tumor necrosis factor (TNF), interferon gamma (IFNϒ), intracellular adhesion molecule-1 (ICAM-1) and monocyte chemotactic protein 1 (MCP-1, CCL2) (S2 Fig, p < 0.05). Wild-type mice showed increased expression of ICAM and reduced expression of MCP in comparison with C5ar-/- mice in placentas from both uninfected and malaria-infected litters (S2 Fig, p < 0.05). Absence of congenital infection was confirmed by blood smears and PCR of fetal blood.


Experimental Malaria in Pregnancy Induces Neurocognitive Injury in Uninfected Offspring via a C5a-C5a Receptor Dependent Pathway.

McDonald CR, Cahill LS, Ho KT, Yang J, Kim H, Silver KL, Ward PA, Mount HT, Liles WC, Sled JG, Kain KC - PLoS Pathog. (2015)

In utero exposure to EMIP induces a cognitive phenotype in offspring that is rescued by genetic and pharmacological blockade of C5a-C5a receptor signaling.(a) Maternal parasitaemia (day one to seven post infection) expressed as percent of infected red blood cells (iRBCs) per total red blood cells counted in wild-type (n = 5) and C5ar-/- dams (n = 5). (b) Weight from one to six weeks of age in wild-type malaria unexposed (n = 14) and wild-type malaria exposed offspring (n = 13), C5ar-/- malaria unexposed (n = 13) and C5ar-/- malaria exposed (n = 14) offspring. (c) Testing Performance (preference ratio) and (d) total exploration time of wild-type unexposed (WT UE, n = 14), wild-type malaria exposed (WT EX, n = 13), C5a receptor knockout unexposed (C5ar-/- UE, n = 13) and C5ar-/- malaria exposed (C5ar-/- EX, n = 14) offspring in the NOR test (P > 0.05). (e) Performance of WT UE (n = 15), WT EX (n = 15), C5ar-/- UE (n = 13) and C5ar-/- EX (n = 15) offspring in the TST test. (f) Testing Performance (preference ratio) and (g) total exploration time of wild-type unexposed (WT UE, n = 11), wild-type malaria exposed (WT EX, n = 12), C5a receptor knockout unexposed (C5ar-/- UE, n = 13) and C5ar-/- malaria exposed (C5ar-/- EX, n = 9) offspring tested at 20 weeks of age in the NOR test. (h) Performance of WT UE (n = 12), WT EX (n = 11), C5ar-/- UE (n = 12) and C5ar-/- EX (n = 10) offspring tested at 20 weeks of age in the TST test. (i) Testing Performance (preference ratio) and (j) total exploration time of UE offspring (n = 11), EX offspring (n = 11), EX offspring of control rabbit antisera treated dams (R-EX, n = 12) and EX offspring of C5a antisera treated dams (αC5a-EX, n = 12) offspring in the NOR test (P > 0.05 for total exploration time). (k) Performance of UE (n = 11), EX (n = 12), R-EX (n = 10) and αC5a EX (n = 12) offspring in the TST test. *P < 0.05, **P < 0.01, ***P < 0.005; one-way ANOVA and post-test. Data are presented as mean +/- SD.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4581732&req=5

ppat.1005140.g005: In utero exposure to EMIP induces a cognitive phenotype in offspring that is rescued by genetic and pharmacological blockade of C5a-C5a receptor signaling.(a) Maternal parasitaemia (day one to seven post infection) expressed as percent of infected red blood cells (iRBCs) per total red blood cells counted in wild-type (n = 5) and C5ar-/- dams (n = 5). (b) Weight from one to six weeks of age in wild-type malaria unexposed (n = 14) and wild-type malaria exposed offspring (n = 13), C5ar-/- malaria unexposed (n = 13) and C5ar-/- malaria exposed (n = 14) offspring. (c) Testing Performance (preference ratio) and (d) total exploration time of wild-type unexposed (WT UE, n = 14), wild-type malaria exposed (WT EX, n = 13), C5a receptor knockout unexposed (C5ar-/- UE, n = 13) and C5ar-/- malaria exposed (C5ar-/- EX, n = 14) offspring in the NOR test (P > 0.05). (e) Performance of WT UE (n = 15), WT EX (n = 15), C5ar-/- UE (n = 13) and C5ar-/- EX (n = 15) offspring in the TST test. (f) Testing Performance (preference ratio) and (g) total exploration time of wild-type unexposed (WT UE, n = 11), wild-type malaria exposed (WT EX, n = 12), C5a receptor knockout unexposed (C5ar-/- UE, n = 13) and C5ar-/- malaria exposed (C5ar-/- EX, n = 9) offspring tested at 20 weeks of age in the NOR test. (h) Performance of WT UE (n = 12), WT EX (n = 11), C5ar-/- UE (n = 12) and C5ar-/- EX (n = 10) offspring tested at 20 weeks of age in the TST test. (i) Testing Performance (preference ratio) and (j) total exploration time of UE offspring (n = 11), EX offspring (n = 11), EX offspring of control rabbit antisera treated dams (R-EX, n = 12) and EX offspring of C5a antisera treated dams (αC5a-EX, n = 12) offspring in the NOR test (P > 0.05 for total exploration time). (k) Performance of UE (n = 11), EX (n = 12), R-EX (n = 10) and αC5a EX (n = 12) offspring in the TST test. *P < 0.05, **P < 0.01, ***P < 0.005; one-way ANOVA and post-test. Data are presented as mean +/- SD.
Mentions: LBW, as a result of preterm birth or FGR, is known to be associated with impaired neurocognitive development [26,27]. Since MIP may cause LBW, these infants would be expected to experience an increased risk of neurocognitive impairment; however the majority of fetuses exposed to malaria in utero do not develop LBW. Therefore, in order to avoid LBW as a confounder and isolate the effects of malaria exposure alone on offspring neurodevelopment, we reduced the inoculum given to dams in a validated model of EMIP [28] from 106 to 105 PEs. This inoculum was associated with the presence of parasitized erythrocytes in the placenta and localized inflammation in the placenta (S1 Fig and S2 Fig). However the 105 inoculum was associated with lower maternal peripheral parasitemia (Fig 1A) and less marked placental pathology than that previously reported with a dose of 106 PEs [28]. This modification eliminated the LBW phenotype in this model and resulted in equivalent birth weights (from 1 to 20 weeks of age) in control pups compared to offspring exposed in utero to EMIP (Figs 1b, 5b and S3 Fig, S4 Fig and S5 Fig). No significant differences were observed in the length of gestation or litter size in this lower inoculum EMIP model (S1 Table). Placentas from malaria-infected litters (wild-type and C5ar-/-) showed placental inflammation as indicated by increased expression of tumor necrosis factor (TNF), interferon gamma (IFNϒ), intracellular adhesion molecule-1 (ICAM-1) and monocyte chemotactic protein 1 (MCP-1, CCL2) (S2 Fig, p < 0.05). Wild-type mice showed increased expression of ICAM and reduced expression of MCP in comparison with C5ar-/- mice in placentas from both uninfected and malaria-infected litters (S2 Fig, p < 0.05). Absence of congenital infection was confirmed by blood smears and PCR of fetal blood.

Bottom Line: The in utero environment profoundly impacts childhood neurodevelopment and behaviour.These deficits were associated with reduced regional brain levels of major biogenic amines and BDNF that were rescued by disruption of C5a-C5aR signaling using genetic and functional approaches.Our results demonstrate that experimental MIP induces neurocognitive deficits in offspring and suggest novel targets for intervention.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.

ABSTRACT
The in utero environment profoundly impacts childhood neurodevelopment and behaviour. A substantial proportion of pregnancies in Africa are at risk of malaria in pregnancy (MIP) however the impact of in utero exposure to MIP on fetal neurodevelopment is unknown. Complement activation, in particular C5a, may contribute to neuropathology and adverse outcomes during MIP. We used an experimental model of MIP and standardized neurocognitive testing, MRI, micro-CT and HPLC analysis of neurotransmitter levels, to test the hypothesis that in utero exposure to malaria alters neurodevelopment through a C5a-C5aR dependent pathway. We show that malaria-exposed offspring have persistent neurocognitive deficits in memory and affective-like behaviour compared to unexposed controls. These deficits were associated with reduced regional brain levels of major biogenic amines and BDNF that were rescued by disruption of C5a-C5aR signaling using genetic and functional approaches. Our results demonstrate that experimental MIP induces neurocognitive deficits in offspring and suggest novel targets for intervention.

No MeSH data available.


Related in: MedlinePlus