BMP9 Protects Septal Neurons from Axotomy-Evoked Loss of Cholinergic Phenotype

Cholinergic projection from the septum to the hippocampus is crucial for normal cognitive function and degeneration of cells and nerve fibers within the septohippocampal pathway contributes to the pathophysiology of Alzheimer's disease. Bone morphogenetic protein (BMP) 9 is a cholinergic differentiating factor during development both in vivo and in vitro.To determine whether BMP9 could protect the adult cholinergic septohippocampal pathway from axotomy-evoked loss of the cholinergic phenotype, we performed unilateral fimbria-fornix transection in mice and treated them with a continuous intracerebroventricular infusion of BMP9 for six days. The number of choline acetyltransferase (CHAT)-positive cells was reduced by 50% in the medial septal nucleus ipsilateral to the lesion as compared to the intact, contralateral side, and BMP9 infusion prevented this loss in a dose-dependent manner. Moreover, BMP9 prevented most of the decline of hippocampal acetylcholine levels ipsilateral to the lesion, and markedly increased CHAT, choline transporter CHT, NGF receptors p75 (NGFR-p75) and TrkA (NTRK1), and NGF protein content in both the lesioned and unlesioned hippocampi. In addition, BMP9 infusion reduced bilaterally hippocampal levels of basic FGF (FGF2) protein.These data indicate that BMP9 administration can prevent lesion-evoked impairment of the cholinergic septohippocampal neurons in adult mice and, by inducing NGF, establishes a trophic environment for these cells

Neuroprotective Actions of Dietary Choline

Choline is an essential nutrient for humans. It is a precursor of membrane phospholipids (e.g., phosphatidylcholine (PC)), the neurotransmitter acetylcholine, and via betaine, the methyl group donor S-adenosylmethionine. High choline intake during gestation and early postnatal development in rat and mouse models improves cognitive function in adulthood, prevents age-related memory decline, and protects the brain from the neuropathological changes associated with Alzheimer’s disease (AD), and neurological damage associated with epilepsy, fetal alcohol syndrome, and inherited conditions such as Down and Rett syndromes. These effects of choline are correlated with modifications in histone and DNA methylation in brain, and with alterations in the expression of genes that encode proteins important for learning and memory processing, suggesting a possible epigenomic mechanism of action. Dietary choline intake in the adult may also influence cognitive function via an effect on PC containing eicosapentaenoic and docosahexaenoic acids; polyunsaturated species of PC whose levels are reduced in brains from AD patients, and is associated with higher memory performance, and resistance to cognitive decline

Prenatal choline supplementation attenuates neuropathological response to status epilepticus in the adult rat hippocampus. Neurobiol. Dis

Prenatal choline supplementation (SUP) protects adult rats against spatial memory deficits observed after excitotoxin-induced status epilepticus (SE). To examine the mechanism underlying this neuroprotection, we determined the effects of SUP on a variety of hippocampal markers known to change in response to SE and thought to underlie ensuing cognitive deficits. Adult offspring from rat dams that received either a control or SUP diet on embryonic days 12-17 were administered saline or kainic acid (i.p.) to induce SE and were euthanized 16 days later. SUP markedly attenuated seizure-induced hippocampal neurodegeneration, dentate cell proliferation, and hippocampal GFAP mRNA expression levels, prevented the loss of hippocampal GAD65 protein and mRNA expression, and altered growth factor expression patterns. SUP also enhanced pre-seizure hippocampal levels of BDNF, NGF, and IGF-1, which may confer a neuroprotective hippocampal microenvironment that dampens the neuropathological response to and/or helps facilitate recovery from SE to protect cognitive function

A Narrative Review on Maternal Choline Intake and Liver Function of the Fetus and the Infant; Implications for Research, Policy, and Practice

Dietary choline is needed to maintain normal health, including normal liver function in adults. Fatty liver induced by a choline-deficient diet has been consistently observed in human and animal studies. The effect of insufficient choline intake on hepatic fat accumulation is specific and reversible when choline is added to the diet. Choline requirements are higher in women during pregnancy and lactation than in young non-pregnant women. We reviewed the evidence on whether choline derived from the maternal diet is necessary for maintaining normal liver function in the fetus and breastfed infants. Studies have shown that choline from the maternal diet is actively transferred to the placenta, fetal liver, and human milk. This maternal-to-child gradient can cause depletion of maternal choline stores and increase the susceptibility of the mother to fatty liver. Removing choline from the diet of pregnant rats causes fatty liver both in the mother and the fetus. The severity of fatty liver in the offspring was found to correspond to the severity of fatty liver in the respective mothers and to the duration of feeding the choline-deficient diet to the mother. The contribution of maternal choline intake in normal liver function of the offspring can be explained by the role of phosphatidylcholine in lipid transport and as a component of cell membranes and the function of choline as a methyl donor that enables synthesis of phosphatidylcholine in the liver. Additional evidence is needed on the effect of choline intake during pregnancy and lactation on health outcomes in the fetus and infant. Most pregnant and lactating women are currently not achieving the adequate intake level of choline through the diet. Therefore, public health policies are needed to ensure sufficient choline intake through adding choline to maternal multivitamin supplements

FGF2 protein levels in hippocampus (HPP).

<p>Mice were treated as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021166#pone-0021166-g004" target="_blank">Fig. 4</a>. FGF2 was measured by ELISA (* p<0.05 BMP9 vs PBS on the same side).</p

NGFR-p75, TrkA and NGF protein levels in hippocampus (HPP).

<p>Mice were treated as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021166#pone-0021166-g004" target="_blank">Fig. 4</a>. NGFR-p75 (** p<0.01 BMP vs PBS on the same side) and TrkA (significant treatment effect of BMP9 by two-way ANOVA, p<0.05) were measured by Western blot (top panel) and the data quantified as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021166#pone-0021166-g005" target="_blank">Fig. 5</a>. NGF was measured by ELISA (* p<0.05, ** p<0.01 BMP9 vs PBS on the same side).</p

BMP9 protects medial septum cholinergic neurons from axotomy-evoked degeneration.

<p>CHAT-positive cells were counted as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021166#pone-0021166-g001" target="_blank">Fig. 1</a> on both sides of the medial septum and the average cell number on the lesioned side is expressed as % of the average cell number on the intact side. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021166#pone-0021166-g002" target="_blank">Fig. 2</a> for representative sections. Using the best fit to a rectangular hyperbola (R² = 0.89) the EC₅₀ value for BMP9 was 1 ng/h. Note, at 15 ng/h and 38 ng/h BMP9 prevented all loss of CHAT-positive neurons.</p

Sections of mouse brain showing a representative image of the unilateral transection of fimbria-fornix (top panel) and the ROI stained with an anti-CHAT antibody (Bottom Panel).

<p>CHAT-positive cells are seen in the medial septum, the diagonal band and in the striatum (bottom panel). The lines show the ROI used for cell count analysis in the medial septum. The ROI was defined by a triangular shape that extended, dorso-ventrally, from the apex of the medial septum (A) to an imaginary line connecting the lower limits of the anterior commissures on each hemisphere (B) and, medio-laterally, from the midline (A) to the outer limits of the medial septal area (C and D).</p