Fetal programming and lactation: modulating gene expression in response to undernutrition during intrauterine life.

BACKGROUND: Adverse environmental conditions during intrauterine life, known as fetal programming, significantly contribute to the development of diseases in adulthood. Fetal programming induced by factors like maternal undernutrition leads to low birth weight and increases the risk of cardiometabolic diseases. METHODS: We studied a rat model of maternal undernutrition during gestation (MUN) to investigate gene expression changes in cardiac tissue using RNA-sequencing of day 0-1 litters. Moreover, we analyzed the impact of lactation at day 21, in MUN model and cross-fostering experiments, on cardiac structure and function assessed by transthoracic echocardiography, and gene expression changes though qPCR. RESULTS: Our analysis identified specific genes with altered expression in MUN rats at birth. Two of them, Agt and Pparg, stand out for being associated with cardiac hypertrophy and fibrosis. At the end of the lactation period, MUN males showed increased expression of Agt and decreased expression of Pparg, correlating with cardiac hypertrophy. Cross-fostering experiments revealed that lactation with control breastmilk mitigated these expression changes reducing cardiac hypertrophy in MUN males. CONCLUSIONS: Our findings highlight the interplay between fetal programming, gene expression, and cardiac hypertrophy suggesting that lactation period is a potential intervention window to mitigate the effects of fetal programming. IMPACT: Heart remodeling involves the alteration of several groups of genes and lactation period plays a key role in establishing gene expression modification caused by fetal programming. We could identify expression changes of relevant genes in cardiac tissue induced by undernutrition during fetal life. We expose the contribution of the lactation period in modulating the expression of Agt and Pparg, relevant genes associated with cardiac hypertrophy. This evidence reveal lactation as a crucial intervention window for preventing or countering fetal programming.

Effect of Supplementation with Coffee and Cocoa By-Products to Ameliorate Metabolic Syndrome Alterations Induced by High-Fat Diet in Female Mice.

Coffee and cocoa manufacturing produces large amounts of waste. Generated by-products contain bioactive compounds with antioxidant and anti-inflammatory properties, suitable for treating metabolic syndrome (MetS). We aimed to compare the efficacy of aqueous extracts and flours from coffee pulp (CfPulp-E, CfPulp-F) and cocoa shell (CcShell-E, CcShell-F) to ameliorate MetS alterations induced by a high-fat diet (HFD). Bioactive component content was assessed by HPLC/MS. C57BL/6 female mice were fed for 6 weeks with HFD followed by 6 weeks with HFD plus supplementation with one of the ingredients (500 mg/kg/day, 5 days/week), and compared to non-supplemented HFD and Control group fed with regular chow. Body weight, adipocyte size and browning (Mitotracker, confocal microscopy), plasma glycemia (basal, glucose tolerance test-area under the curve, GTT-AUC), lipid profile, and leptin were compared between groups. Cocoa shell ingredients had mainly caffeine, theobromine, protocatechuic acid, and flavan-3-ols. Coffee pulp showed a high content in caffeine, protocatechuic, and chlorogenic acids. Compared to Control mice, HFD group showed alterations in all parameters. Compared to HFD, CcShell-F significantly reduced adipocyte size, increased browning and high-density lipoprotein cholesterol (HDL), and normalized basal glycemia, while CcShell-E only increased HDL. Both coffee pulp ingredients normalized adipocyte size, basal glycemia, and GTT-AUC. Additionally, CfPulp-E improved hyperleptinemia, reduced triglycerides, and slowed weight gain, and CfPulp-F increased HDL. In conclusion, coffee pulp ingredients showed a better efficacy against MetS, likely due to the synergic effect of caffeine, protocatechuic, and chlorogenic acids. Since coffee pulp is already approved as a food ingredient, this by-product could be used in humans to treat obesity-related MetS alterations.

Slower Growth during Lactation Rescues Early Cardiovascular and Adipose Tissue Hypertrophy Induced by Fetal Undernutrition in Rats.

Low birth weight (LBW) and accelerated growth during lactation are associated with cardiometabolic disease development. LBW offspring from rats exposed to undernutrition during gestation (MUN) develops hypertension. In this rat model, we tested if slower postnatal growth improves early cardiometabolic alterations. MUN dams were fed ad libitum during gestation days 1-10, with 50% of the daily intake during days 11-21 and ad libitum during lactation. Control dams were always fed ad libitum. Pups were maintained with their own mother or cross-fostered. Body weight and length were recorded weekly, and breastmilk was obtained. At weaning, the heart was evaluated by echocardiography, and aorta structure and adipocytes in white perivascular fat were studied by confocal microscopy (size, % beige-adipocytes by Mitotracker staining). Breastmilk protein and fat content were not significantly different between groups. Compared to controls, MUN males significantly accelerated body weight gain during the exclusive lactation period (days 1-14) while females accelerated during the last week; length growth was slower in MUN rats from both sexes. By weaning, MUN males, but not females, showed reduced diastolic function and hypertrophy in the heart, aorta, and adipocytes; the percentage of beige-type adipocytes was smaller in MUN males and females. Fostering MUN offspring on control dams significantly reduced weight gain rate, cardiovascular, and fat hypertrophy, increasing beige-adipocyte proportion. Control offspring nursed by MUN mothers reduced body growth gain, without cardiovascular modifications. In conclusion, slower growth during lactation can rescue early cardiovascular alterations induced by fetal undernutrition. Exclusive lactation was a key period, despite no modifications in breastmilk macronutrients, suggesting the role of bioactive components. Our data support that lactation is a key period to counteract cardiometabolic disease programming in LBW and a potential intervention window for the mother.

Selective role of the DNA helicase Mcm5 in BMP retrograde signaling during Drosophila neuronal differentiation.

The MCM2-7 complex is a highly conserved hetero-hexameric protein complex, critical for DNA unwinding at the replicative fork during DNA replication. Overexpression or mutation in MCM2-7 genes is linked to and may drive several cancer types in humans. In mice, mutations in MCM2-7 genes result in growth retardation and mortality. All six MCM2-7 genes are also expressed in the developing mouse CNS, but their role in the CNS is not clear. Here, we use the central nervous system (CNS) of Drosophila melanogaster to begin addressing the role of the MCM complex during development, focusing on the specification of a well-studied neuropeptide expressing neuron: the Tv4/FMRFa neuron. In a search for genes involved in the specification of the Tv4/FMRFa neuron we identified Mcm5 and find that it plays a highly specific role in the specification of the Tv4/FMRFa neuron. We find that other components of the MCM2-7 complex phenocopies Mcm5, indicating that the role of Mcm5 in neuronal subtype specification involves the MCM2-7 complex. Surprisingly, we find no evidence of reduced progenitor proliferation, and instead find that Mcm5 is required for the expression of the type I BMP receptor Tkv, which is critical for the FMRFa expression. These results suggest that the MCM2-7 complex may play roles during CNS development outside of its well-established role during DNA replication.

Hypothyroidism confers tolerance to cerebral malaria.

The modulation of the host's metabolism to protect tissue from damage induces tolerance to infections increasing survival. Here, we examined the role of the thyroid hormones, key metabolic regulators, in the outcome of malaria. Hypothyroidism confers protection to experimental cerebral malaria by a disease tolerance mechanism. Hypothyroid mice display increased survival after infection with Plasmodium berghei ANKA, diminishing intracranial pressure and brain damage, without altering pathogen burden, blood-brain barrier disruption, or immune cell infiltration. This protection is reversed by treatment with a Sirtuin 1 inhibitor, while treatment of euthyroid mice with a Sirtuin 1 activator induces tolerance and reduces intracranial pressure and lethality. This indicates that thyroid hormones and Sirtuin 1 are previously unknown targets for cerebral malaria treatment, a major killer of children in endemic malaria areas.

Implication of RAS in Postnatal Cardiac Remodeling, Fibrosis and Dysfunction Induced by Fetal Undernutrition.

Fetal undernutrition is a risk factor for cardiovascular diseases. Male offspring from rats exposed to undernutrition during gestation (MUN) exhibit oxidative stress during perinatal life and develop cardiac dysfunction in ageing. Angiotensin-II is implicated in oxidative stress-mediated cardiovascular fibrosis and remodeling, and lactation is a key developmental window. We aimed to assess if alterations in RAS during lactation participate in cardiac dysfunction associated with fetal undernutrition. Control dams received food ad libitum, and MUN had 50% nutrient restriction during the second half of gestation. Both dams were fed ad libitum during lactation, and male offspring were studied at weaning. We assessed: ventricular structure and function (echocardiography); blood pressure (intra-arterially, anesthetized rats); collagen content and intramyocardial artery structure (Sirius red, Masson Trichromic); myocardial and intramyocardial artery RAS receptors (immunohistochemistry); plasma angiotensin-II (ELISA) and TGF-ß1 protein expression (Western Blot). Compared to Control, MUN offspring exhibited significantly higher plasma Angiotensin-II and a larger left ventricular mass, as well as larger intramyocardial artery media/lumen, interstitial collagen and perivascular collagen. In MUN hearts, TGF-ß1 tended to be higher, and the end-diastolic diameter and E/A ratio were significantly lower with no differences in ejection fraction or blood pressure. In the myocardium, no differences between groups were detected in AT1, AT2 or Mas receptors, with MrgD being significantly lower in the MUN group. In intramyocardial arteries from MUN rats, AT1 and Mas receptors were significantly elevated, while AT2 and MrgD were lower compared to Control. Conclusions. In rats exposed to fetal undernutrition, RAS disbalance and associated cardiac remodeling during lactation may set the basis for later heart dysfunction.

Specification of Drosophila neuropeptidergic neurons by the splicing component brr2.

During embryonic development, a number of genetic cues act to generate neuronal diversity. While intrinsic transcriptional cascades are well-known to control neuronal sub-type cell fate, the target cells can also provide critical input to specific neuronal cell fates. Such signals, denoted retrograde signals, are known to provide critical survival cues for neurons, but have also been found to trigger terminal differentiation of neurons. One salient example of such target-derived instructive signals pertains to the specification of the Drosophila FMRFamide neuropeptide neurons, the Tv4 neurons of the ventral nerve cord. Tv4 neurons receive a BMP signal from their target cells, which acts as the final trigger to activate the FMRFa gene. A recent FMRFa-eGFP genetic screen identified several genes involved in Tv4 specification, two of which encode components of the U5 subunit of the spliceosome: brr2 (l(3)72Ab) and Prp8. In this study, we focus on the role of RNA processing during target-derived signaling. We found that brr2 and Prp8 play crucial roles in controlling the expression of the FMRFa neuropeptide specifically in six neurons of the VNC (Tv4 neurons). Detailed analysis of brr2 revealed that this control is executed by two independent mechanisms, both of which are required for the activation of the BMP retrograde signaling pathway in Tv4 neurons: (1) Proper axonal pathfinding to the target tissue in order to receive the BMP ligand. (2) Proper RNA splicing of two genes in the BMP pathway: the thickveins (tkv) gene, encoding a BMP receptor subunit, and the Medea gene, encoding a co-Smad. These results reveal involvement of specific RNA processing in diversifying neuronal identity within the central nervous system.

Evolutionarily conserved anterior expansion of the central nervous system promoted by a common PcG-Hox program.

A conserved feature of the central nervous system (CNS) is the prominent expansion of anterior regions (brain) compared with posterior (nerve cord). The cellular and regulatory processes driving anterior CNS expansion are not well understood in any bilaterian species. Here, we address this expansion in Drosophila and mouse. We find that, compared with the nerve cord, the brain displays extended progenitor proliferation, more elaborate daughter cell proliferation and more rapid cell cycle speed in both Drosophila and mouse. These features contribute to anterior CNS expansion in both species. With respect to genetic control, enhanced brain proliferation is severely reduced by ectopic Hox gene expression, by either Hox misexpression or by loss of Polycomb group (PcG) function. Strikingly, in PcG mutants, early CNS proliferation appears to be unaffected, whereas subsequent brain proliferation is severely reduced. Hence, a conserved PcG-Hox program promotes the anterior expansion of the CNS. The profound differences in proliferation and in the underlying genetic mechanisms between brain and nerve cord lend support to the emerging concept of separate evolutionary origins of these two CNS regions.

Anterior-Posterior Gradient in Neural Stem and Daughter Cell Proliferation Governed by Spatial and Temporal Hox Control.

A readily evident feature of animal central nervous systems (CNSs), apparent in all vertebrates and many invertebrates alike, is its "wedge-like" appearance, with more cells generated in anterior than posterior regions. This wedge could conceivably be established by an antero-posterior (A-P) gradient in the number of neural progenitor cells, their proliferation behaviors, and/or programmed cell death (PCD). However, the contribution of each of these mechanisms, and the underlying genetic programs, are not well understood. Building upon recent progress in the Drosophila melanogaster (Drosophila) ventral nerve cord (VNC), we address these issues in a comprehensive manner. We find that, although PCD plays a role in controlling cell numbers along the A-P axis, the main driver of the wedge is a gradient of daughter proliferation, with divisions directly generating neurons (type 0) being more prevalent posteriorly and dividing daughters (type I) more prevalent anteriorly. In addition, neural progenitor (NB) cell-cycle exit occurs earlier posteriorly. The gradient of type I > 0 daughter proliferation switch and NB exit combine to generate radically different average lineage sizes along the A-P axis, differing by more than 3-fold in cell number. We find that the Hox homeotic genes, expressed in overlapping A-P gradients and with a late temporal onset in NBs, trigger the type I > 0 daughter proliferation switch and NB exit. Given the highly evolutionarily conserved expression of overlapping Hox homeotic genes in the CNS, our results point to a common mechanism for generating the CNS wedge.

Chronic stress effects on adrenal cortex cellular proliferation in pregnant rats / Efectos del estrés crónico sobre la proliferación celular en la corteza suprarrenal en ratas preñadas

Chronic stress by immobilization during pregnancy may cause alterations in mechanisms maintaining homeostasis in the adrenal gland. The objective of this study was to quantify cellular proliferation index in the adrenal cortex during pregnancy second half and assess the effects of chronic stress on it. Adrenal cortex proliferation index in stressed rats showed a significant decrease at 12 and 17 days of gestation, while at day 21 it did not show differences with the control treatments. Moreover, proliferation index of reticular zones in control and experimental rats, exhibited a significant reduction in comparison to glomerular and fascicular zones of adrenal cortex during the three gestation days studied. In conclusion, chronic stress by immobilization produces a decrease in cellular proliferation index at 12 and 17 gestation days, which may be related to changes in plasmatic concentrations of corticosterone and prolactin and, to the reduction of specific growth factors. Furthermore, the observed proliferation diminishment in reticular zone regarding the other cortical zones would be consistent with the migration theory of adrenal cells.

El estrés crónico por inmovilización durante la gestación puede provocar alteraciones de los mecanismos que mantienen la homeostasis en la glándula adrenal. El objetivo de este trabajo fue cuantificar el índice de proliferación en la corteza adrenal durante la segunda mitad de la gestación y comprobar los efectos que produce el estrés crónico sobre el mismo. El índice de proliferación en la corteza adrenal de ratas estresadas presentó una disminución significativa a los 12 y 17 días de gestación, mientras que en el día 21 no presentó modificaciones con respecto a sus controles. Por otro lado, el índice de proliferación de la zona reticular en ratas controles y experimentales, presentó una disminución significativa con respecto a las zonas glomerular y fascicular de la corteza adrenal en los tres días de la gestación estudiados. Se puede concluir que el estrés crónico por inmovilización produce disminución del índice de proliferación celular a los 12 y 17 días de la gestación que podría estar en relación con las variaciones de las concentraciones plasmáticas de corticosterona, prolactina, y con la disminución de factores de crecimiento específicos. Asimismo, la disminución de la proliferación en la zona reticular en relación con las otras zonas corticales estaría en concordancia con la teoría de la migración celular adrenal.