The SIRT3/GSK-3ß/GLUT4 axis might be involved in maternal hypoxia-induced skeletal muscle insulin resistance in old male rat offspring.

Maternal hypoxia is strongly linked to insulin resistance (IR) in adult offspring, and altered insulin signaling for muscle glucose uptake is thought to play a central role. However, whether the SIRT3/GSK-3ß/GLUT4 axis is involved in maternal hypoxia-induced skeletal muscle IR in old male rat offspring has not been investigated. Maternal hypoxia was established from Days 5 to 21 of pregnancy by continuous infusion of nitrogen and air. The biochemical parameters and levels of key insulin signaling molecules of old male rat offspring were determined through a series of experiments. Compared to the control (Ctrl) old male rat offspring group, the hypoxic (HY) group exhibited elevated fasting blood glucose (FBG) (∼30%), fasting blood insulin (FBI) (∼35%), total triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C), as well as results showing impairment in the glucose tolerance test (GTT) and insulin tolerance test (ITT). In addition, hematoxylin-eosin (HE) staining and transmission electron microscopy (TEM) revealed impaired cellular structures and mitochondria in the longitudinal sections of skeletal muscle from HY group mice, which might be associated with decreased SIRT3 expression. Furthermore, the expression of insulin signaling molecules, such as GSK-3ß and GLUT4, was also altered. In conclusion, the present results indicate that the SIRT3/GSK-3ß/GLUT4 axis might be involved in maternal hypoxia-induced skeletal muscle IR in old male rat offspring.

Paternal preconception alcohol consumption increased Angiotensin II-mediated vasoconstriction in male offspring cerebral arteries via oxidative stress-AT1R pathway.

Alcohol consumption is popular worldwidely and closely associated with cardiovascular diseases. Influences of paternal preconception alcohol consumption on offspring cerebral arteries are largely unknown. Male rats were randomly given alcohol or water before being mated with alcohol-naive females to produce alcohol- and control-sired offspring. Middle cerebral artery (MCA) was tested with a Danish Myo Technology wire myograph, patch-clamp, IONOPTIX, immunofluorescence and quantitative PCR. Alcohol consumption enhanced angiotensin II (AngII)-mediated constriction in male offspring MCA mainly via AT1R. PD123,319 only augmented AngII-induced constriction in control offspring. AngII and Bay K8644 induced stronger intracellular calcium transient in vascular smooth muscle cells (VSMCs) from MCA of alcohol offspring. L-type voltage-dependent calcium channel (L-Ca2+ ) current at baseline and after AngII-stimulation was higher in VSMCs. Influence of large-conductance calcium-activated potassium channel (BKC a ) was lower. Caffeine induced stronger constriction and intracellular calcium release in alcohol offspring. Superoxide anion was higher in alcohol MCA than control. Tempol and thenoyltrifluoroacetone alleviated AngII-mediated contractions, while inhibition was significantly higher in alcohol group. The mitochondria were swollen in alcohol MCA. Despite lower Kcnma1 and Prkce expression, many genes expressions were higher in alcohol group. Hypoxia induced reactive oxygen species production and increased AT1R expression in control MCA and rat aorta smooth muscle cell line. In conclusion, this study firstly demonstrated paternal preconception alcohol potentiated AngII-mediated vasoconstriction in offspring MCA via ROS-AT1R. Alcohol consumption increased intracellular calcium via L-Ca2+ channel and endoplasmic reticulum and decreased BKCa function. The present study provided new information for male reproductive health and developmental origin of cerebrovascular diseases.

In vitro fertilization with frozen embryo transfer increased histamine-mediated contractile sensitivity via PKCß in human umbilical vein.

OBJECTIVE: In vitro fertilization-embryo transfer (IVF-ET) technologies (especially frozen ET) have been widely used, which might affect maternal and fetal health. Information regarding influence of IVF-ET on the vasoconstriction of human umbilical vein (HUV) is limited. This study determined effects of frozen ET on histamine-mediated vascular responses in HUV and related mechanisms. METHODS AND RESULTS: HUVs were collected from frozen ET conceived pregnancy and spontaneously conceived pregnancy (control). Histamine concentration in umbilical plasma was higher in frozen ET group than the control. Histamine-mediated contractile response curve was left-shifted in the frozen ET group when comparing with the control. In isolated HUV rings, H1R showed a critical role in regulating vascular constriction, while H2R played little roles in regulating vessel tone. Iberiotoxin and 4-aminopyridine didn't significantly change histamine-mediated constriction in HUVs. Histamine-induced vasoconstrictions were significantly decreased by nifedipine, KN93, or GF109203X, while the inhibitory effects were significantly greater in the frozen ET group in comparison to the control. The constrictions by Bay K8644, phenylephrine, or PDBu were stronger in frozen ET, respectively. There was a decrease in the protein expressions of H1R and H2R, an increase in protein expressions of BKCaα and PKCß. CONCLUSIONS: Histamine-induced constriction in HUV was mainly via H1R. The increased sensitivity to histamine in HUV following frozen ET cycles were linked to the enhanced PKCß protein expression and function. The new data and findings in this study provide important insight into influences of frozen ET on fetal vessel development and potential influence in long-term.

Point-of-Care and Dual-Response Detection of Hydrazine/Hypochlorite-Based on a Smart Hydrogel Sensor and Applications in Information Security and Bioimaging.

A novel dual-response fluorescence probe (XBT-CN) was developed by using a fluorescence priming strategy for quantitative monitoring and visualization of hydrazine (N2H4) and hypochlorite (ClO-). With the addition of N2H4/ClO-, the cleavage reaction of C=C bond initiated by N2H4/ClO- was transformed into corresponding hydrazone and aldehyde derivatives, inducing the probe XBT-CN appeared a fluorescence "off-on" response, which was verified by DFT calculation. HRMS spectra were also conducted to confirm the sensitive mechanism of XBT-CN to N2H4 and ClO-. The probe XBT-CN had an obvious fluorescence response to N2H4 and ClO-, which caused a significant color change in unprotected eyes. In addition, the detection limits of XBT-CN for N2H4 and ClO- were 27 nM and 34 nM, respectively. Interference tests showed that other competitive analytes could hardly interfere with the detection of N2H4 and ClO- in a complex environment. In order to realize the point-of-care detection of N2H4 and ClO-, an XBT-CN@hydrogel test kit combined with a portable smartphone was developed. Furthermore, the portable test kit has been applied to the detection of N2H4 and ClO- in a real-world environment and food samples, and a series of good results have been achieved. Attractively, we demonstrated that XBT-CN@hydrogel was successfully applied as an encryption ink in the field of information security. Finally, the probe can also be used to monitor and distinguish N2H4 and ClO- in living cells, exhibiting excellent biocompatibility and low cytotoxicity.

Antenatal Dexamethasone Exposure Impairs the High-Conductance Ca2+-Activated K+ Channels via Epigenetic Alteration at Gene Promoter in Male Offspring.

OBJECTIVE: Antenatal exposure to glucocorticoids increases cardiovascular risks related to vascular dysfunctions in offspring, although underlying mechanisms are still unknown. As an important vascular mediator, high-conductance Ca2+-activated K+ channels (BK) plays an essential role in determining vascular tone. Long-term effects of antenatal glucocorticoids on BK in offspring are largely unknown. This study examined the effects and mechanisms of antenatal exposure to clinically relevant doses of glucocorticoids on vascular BK in offspring. Approach and Results: Pregnant Sprague-Dawley rats received synthetic glucocorticoids dexamethasone or vehicle during the last week of pregnancy. Vascular functions, cellular electrophysiology, target gene expression, and promoter methylation were examined in mesenteric arteries of male offspring (gestational day 21 [fetus] and postnatal day 120 [adult offspring]). Antenatal dexamethasone exposure impaired BK activators-mediated relaxation and reduced whole-cell BK currents in mesenteric arteries. Antenatal dexamethasone exposure did not alter Ca2+/voltage-sensitivity of BK but downregulated the expressions of BK α and ß1 subunits in both fetal and adult mesenteric arteries. In addition, increased promoter methylations within BKα and BKß1 were compatible with reduced expressions of the 2 genes. CONCLUSIONS: Our findings showed a profound and long-term impact of antenatal dexamethasone exposure on vascular BK via an altered epigenetic pattern from fetal stage to adulthood, advancing understanding of prolonged adverse effects and mechanisms of antenatal glucocorticoids exposure on vascular health in offspring.

Prenatal hypoxia inhibited propionate-evoked BK channels of mesenteric artery smooth muscle cells in offspring.

As a common complication of pregnancy, gestational hypoxia has been shown to predispose offspring to vascular dysfunction. Propionate, one of short-chain fatty acids, exerts cardioprotective effects via reducing blood pressure. This study examined whether prenatal hypoxia impaired propionate-stimulated large-conductance Ca2+ -activated K+ (BK) channel activities in vascular smooth muscle cells (VSMCs) of offspring. Pregnant rats were exposed to hypoxia (10.5% oxygen) and normoxia (21% oxygen) from gestational day 7-21. At 6 weeks of age, VSMCs in mesenteric arteries of offspring were analysed for BK channel functions and gene expressions. It was shown firstly that propionate could open significantly BK single channel in VSMCs in a concentration-dependent manner. Antagonists of G protein ßγ subunits and inositol trisphosphate receptor could completely suppress the activation of BK by propionate, respectively. Gαi/o and ryanodine receptor were found to participate in the stimulation on BK. Compared to the control, vasodilation and increments of BK NPo (the open probability) evoked by propionate were weakened in the offspring by prenatal hypoxia with down-regulated Gßγ and PLCß. It was indicated that prenatal hypoxia inhibited propionate-stimulated BK activities in mesenteric VSMCs of offspring via reducing expressions of Gßγ and PLCß, in which endoplasmic reticulum calcium release might be involved.

Prostaglandin I2 mediates weak vasodilatation in human placental microvessels.

Human placental vessels (HPVs) play important roles in the exchange of metabolites and oxygen in maternal-fetal circulation. Endothelial-derived prostacyclin (prostaglandin I2, PGI2) is a critical endothelial vasodilator in the body. However, the physiological and pharmacological functions of endothelial PGI2 in the human placenta are still unclear. Human, sheep, and rat blood vessels were used in this study. Unlike non-placental vessels (non-PVs), the PGI2 synthesis inhibitor tranylcypromine (TCP) did not modify 5-hydroxytryptamine (5-HT)-induced vascular contraction, indicating that endothelial-derived PGI2 was weak in PVs. Vascular responses to exogenous PGI2 showed slight relaxation followed by a significant contraction at a higher concentration in HPV, which was inhibited by the thromboxane-prostanoid (TP) receptors antagonist SQ-29,548. Testing PVs and non-PVs from sheep also showed similar functional results. More TP receptors than PGI2 (IP) receptors were observed in HPVs. The whole-cell K+ current density of HPVs was significantly weaker than that of non-PVs. This study demonstrated the specific characteristics of the placental endogenous endothelial PGI2 system and the patterns of placental vascular physiological/pharmacological response to exogenous PGI2, showing that placental endothelial PGI2 does not markedly contribute to vascular dilation in the human placenta, in notable contrast to non-PVs. The results provide crucial information for understanding the endothelial roles of HPVs, which may be helpful for further investigations of potential targets in the treatment of diseases such as preeclampsia.

DNA methylation-reprogrammed oxytocin receptor underlies insensitivity to oxytocin in pre-eclamptic placental vasculature.

Pre-eclampsia is associated with inadequate placental blood flow and placental ischaemia. Placental vascular tone is essential for maintaining adequate placental blood flow. Oxytocin is increased in placental system at late pregnancy and onset of labour, and presented strongly concentration-dependent contractions in placental vascular, suggesting that oxytocin could be involved in regulating placental vascular tone and circulation. However, information about the reactivity of oxytocin in pre-eclamptic placental vasculature is limited. This study used a large number of human placentas to reveal the pathophysiological changes and its underlying mechanisms of oxytocin-induced vasoconstrictions in placental vessels under pre-eclamptic condition. Present study found that oxytocin-induced contractions were significantly decreased in human pre-eclamptic placental vasculature, associated with a deactivated transcription of oxytocin receptor gene. The deactivated oxytocin receptor gene transcription was ascribed to a relatively higher DNA methylation status of CpG islands in oxytocin receptor gene promoter. This study was first to reveal that a hyper-methylation of CpG islands in oxytocin receptor gene promoter, leading to a relatively low pattern of oxytocin receptor expression, was responsible for the decreased sensitivity of oxytocin in pre-eclamptic placental vessels.

Prenatal hypoxia plus postnatal high-fat diet exacerbated vascular dysfunction via up-regulated vascular Cav1.2 channels in offspring rats.

BACKGROUND: This study aimed to examine whether and how postnatal high-fat diet had additional impact on promoting vascular dysfunction in the offspring exposed to prenatal hypoxia. METHODS AND RESULTS: Pregnant Sprague-Dawley rats were randomly assigned to hypoxia (10.5% oxygen) or normoxia (21% O2 ) groups from gestation days 5-21. A subset of male offspring was placed on a high-fat diet (HF, 45% fat) from 4-16 weeks of age. Prenatal hypoxia induced a decrease in birth weight. In offspring-fed HF diet, prenatal hypoxia was associated with increased fasting plasma triglyceride, total cholesterol, free fatty acids, and low-density lipoprotein-cholesterol. Compared with the other three groups, prenatal hypoxic offspring with high-fat diet showed a significant increase in blood pressure, phenylephrine-mediated vasoconstrictions, L-type voltage-gated Ca2+ (Cav1.2) channel currents, and elevated mRNA and protein expression of Cav1.2 α1 subunit in mesenteric arteries or myocytes. The large-conductance Ca2+-activated K+ (BK) channels currents and the BK channel units (ß1, not α-subunits) were significantly increased in mesenteric arteries or myocytes in HF offspring independent of prenatal hypoxia factor. CONCLUSION: The results demonstrated that prenatal hypoxia followed by postnatal HF caused vascular dysfunction through ion channel remodelling in myocytes.

Methylation-reprogrammed Wnt/ß-catenin signalling mediated prenatal hypoxia-induced brain injury in foetal and offspring rats.

Prenatal hypoxia (PH) is a common pregnancy complication, harmful to brain development. This study investigated whether and how PH affected Wnt pathway in the brain. Pregnant rats were exposed to hypoxia (10.5% O2 ) or normoxia (21% O2 ; Control). Foetal brain weight and body weight were decreased in the PH group, the ratio of brain weight to body weight was increased significantly. Prenatal hypoxia increased mRNA expression of Wnt3a, Wnt7a, Wnt7b and Fzd4, but not Lrp6. Activated ß-catenin protein and Fosl1 expression were also significantly up-regulated. Increased Hif1a expression was found in the PH group associated with the higher Wnt signalling. Among 5 members of the Sfrp family, Sfrp4 was down-regulated. In the methylation-regulating genes, higher mRNA expressions of Dnmt1 and Dnmt3b were found in the PH group. Sodium bisulphite and sequencing revealed hyper-methylation in the promoter region of Sfrp4 gene in the foetal brain, accounting for its decreased expression and contributing to the activation of the Wnt-Catenin signalling. The study of PC12 cells treated with 5-aza further approved that decreased methylation could result in the higher Sfrp4 expression. In the offspring hippocampus, protein levels of Hif1a and mRNA expression of Sfrp4 were unchanged, whereas Wnt signal pathway was inhibited. The data demonstrated that PH activated the Wnt pathway in the foetal brain, related to the hyper-methylation of Sfrp4 as well as Hif1a signalling. Activated Wnt signalling might play acute protective roles to the foetal brain in response to hypoxia, also would result in disadvantageous influence on the offspring in long-term.

5-Hydroxymethylcytosine-mediated alteration of transposon activity associated with the exposure to adverse in utero environments in human.

Preeclampsia and gestational diabetes mellitus (GDM) are the most common clinical conditions in pregnancy that could result in adverse in utero environments. Fetal exposure to poor environments may raise the long-term risk of postnatal disorders, while epigenetic modifications could be involved. Recent research has implicated involvement of 5-hydroxymethylcytosine (5hmC), a DNA base derived from 5-methylcytosine, via oxidation by ten-eleven translocation (TET) enzymes, in DNA methylation-related plasticity. Here, we show that the TET2 expression and 5hmC abundance are significantly altered in the umbilical veins of GDM and preeclampsia. Genome-wide profiling of 5hmC revealed its specific reduction on intragenic regions from both GDM and preeclampsia compared to healthy controls. Gene Ontology analysis using loci bearing unique GDM- and preeclampsia-specific loss-of-5hmC indicated its impact on several critical biological pathways. Interestingly, the substantial alteration of 5hmC on several transposons and repetitive elements led to their differential expression. The alteration of TET expression, 5hmC levels and 5hmC-mediated transposon activity was further confirmed using established hypoxia cell culture model, which could be rescued by vitamin C, a known activator of TET proteins. Together, these results suggest that adverse pregnancy environments could influence 5hmC-mediated epigenetic profile and contribute to abnormal development of fetal vascular systems that may lead to postnatal diseases.

Chronic Prenatal Hypoxia Down-Regulated BK Channel Β1 Subunits in Mesenteric Artery Smooth Muscle Cells of the Offspring.

BACKGROUND/AIMS: Chronic hypoxia in utero could impair vascular functions in the offspring, underlying mechanisms are unclear. This study investigated functional alteration in large-conductance Ca2+-activated K+ (BK) channels in offspring mesenteric arteries following prenatal hypoxia. METHODS: Pregnant rats were exposed to normoxic control (21% O2, Con) or hypoxic (10.5% O2, Hy) conditions from gestational day 5 to 21, their 7-month-old adult male offspring were tested for blood pressure, vascular BK channel functions and expression using patch clamp and wire myograh technique, western blotting, and qRT-PCR. RESULTS: Prenatal hypoxia increased pressor responses and vasoconstrictions to phenylephrine in the offspring. Whole-cell currents density of BK channels and amplitude of spontaneous transient outward currents (STOCs), not the frequency, were significantly reduced in Hy vascular myocytes. The sensitivity of BK channels to voltage, Ca2+, and tamoxifen were reduced in Hy myocytes, whereas the number of channels per patch and the single-channel conductance were unchanged. Prenatal hypoxia impaired NS1102- and tamoxifen-mediated relaxation in mesenteric arteries precontracted with phenylephrine in the presence of Nω-nitro-L-arginine methyl ester. The mRNA and protein expression of BK channel ß1, not the α-subunit, was decreased in Hy mesenteric arteries. CONCLUSIONS: Impaired BK channel ß1-subunits in vascular smooth muscle cells contributed to vascular dysfunction in the offspring exposed to prenatal hypoxia.

Maternal high-sucrose diets altered vascular large-conductance Ca2+-activated K+ channels via reactive oxygen species in offspring rats.

Overnutrition during pregnancy could increase risks of cardiovascular diseases in late life. This study investigated whether and how reactive oxygen species (ROS) may influence functions of large-conductance Ca2+-activated K+ channels (BKCa) in the offspring exposed to prenatal high sucrose (HS). We found that prenatal HS diets significantly increased phenylephrine (PE)-induced vessel contractions in mesenteric arteries of the adult offspring. Pretreatment with iberiotoxin (BKCa blocker, IBTX) significantly increased PE-mediated vascular contractions in the control, not in the HS group. Electrophysiological studies demonstrated that BKCa current density and single-channel current were reduced in the vascular smooth muscle cells (VSMCs) of the HS offspring. The expression of BKCa alpha, beta1 subunits in mesenteric arteries was decreased in the HS offspring, indicating that both activity and number of BKCa channels in HS offspring were reduced. Superoxide production and NADPH oxidase (NOX)4 of the HS offspring were elevated. Following inhibiting NOX by apocynin, vasoconstriction in the HS offspring was weakened and the reduced currents in the VSMCs were improved with altered protein kinase B (AKT) pathway. The results suggested that NOX4-derived ROS might inhibit the offspring vascular BKCa channel activity via AKT pathway.

Antenatal hypoxia induces epigenetic repression of glucocorticoid receptor and promotes ischemic-sensitive phenotype in the developing heart.

Large studies in humans and animals have demonstrated a clear association of an adverse intrauterine environment with an increased risk of cardiovascular disease later in life. Yet mechanisms remain largely elusive. The present study tested the hypothesis that gestational hypoxia leads to promoter hypermethylation and epigenetic repression of the glucocorticoid receptor (GR) gene in the developing heart, resulting in increased heart susceptibility to ischemia and reperfusion injury in offspring. Hypoxic treatment of pregnant rats from day 15 to 21 of gestation resulted in a significant decrease of GR exon 14, 15, 16, and 17 transcripts, leading to down-regulation of GR mRNA and protein in the fetal heart. Functional cAMP-response elements (CREs) at -4408 and -3896 and Sp1 binding sites at -3425 and -3034 were identified at GR untranslated exon 1 promoters. Hypoxia significantly increased CpG methylation at the CREs and Sp1 binding sites and decreased transcription factor binding to GR exon 1 promoter, accounting for the repression of the GR gene in the developing heart. Of importance, treatment of newborn pups with 5-aza-2'-deoxycytidine reversed hypoxia-induced promoter methylation, restored GR expression and prevented hypoxia-mediated increase in ischemia and reperfusion injury of the heart in offspring. The findings demonstrate a novel mechanism of epigenetic repression of the GR gene in fetal stress-mediated programming of ischemic-sensitive phenotype in the heart.

Chronic hypoxia in pregnancy affects thymus development in Balb/c mouse offspring via IL2 Signaling.

Hypoxia during pregnancy can adversely affect development. This study, addressed the impact of prenatal hypoxia on thymus development in the rodent offspring. Pregnant Balb/c mice were exposed to hypoxia or normoxia during pregnancy, and the thymuses of their offspring were tested. Chronic hypoxia during pregnancy resulted in significantly decreased fetal body weight, with an increased thymus-to-body weight ratio. Histological analysis revealed a smaller cortical zone in the thymus of the offspring exposed to hypoxia. A reduction in the cortical T lymphocyte population corresponded to increased mRNA abundance of caspase 3 (Casp3) and decreased expression of the proliferation marker Ki-67 (Mki67). Differences in T lymphocyte sub-populations in the thymus further indicate that thymus development in offspring was retarded or stagnated by prenatal hypoxia. The abundance of IL2 and its receptor was reduced in the thymus following prenatal hypoxia. This was accompanied by an increase in thymus HIF1A and IKKß and a decrease in phosphorylated NFKB, MAP2K1, and MAPK1/3 compared to control pregnancies. Together, these results implicate deficiencies in IL2-mediated signaling as one source of prenatal-hypoxia-impaired thymus development.

Ultrasound-accelerated organogel: application for visual discrimination of Hg(2+) from Ag(+).

A new kind of naphthalimide-based organogelator, TN, was designed and synthesized. The intramolecular guanylation of TN promoted by Hg(2+) or Ag(+) in both solution and gel state was studied through several approaches including FL, UV-visible, NMR, FT-IR and SEM experiments. TN could selectively sense Hg(2+) and Ag(+) ions with obvious fluorescence quenching and color changes from yellow to colorless among test ions in the solution state. Interestingly, the S-gel of TN could be used to selectively discriminate Hg(2+) from Ag(+)via phase and morphology changes. Hg(2+) ions triggered the gel-to-gel transition with morphology changes of the TN S-gel from nanofibrils to porous sheet structure, together with fluorescence quenching. In contrast, the gel collapsed in the presence of Ag(+) ions, which was comprised of short and disordered fiber structure. To the best of the authors' knowledge, this is the first example of gels selectively sensing Hg(2+) or Ag(+)via a reaction approach.

Disrupting the circadian photo-period alters the release of follicle-stimulating hormone, luteinizing hormone, progesterone, and estradiol in maternal and fetal sheep.

Although a large number of studies show that photo-period disruption potentially affects hormone secretion in mammals, information about the effects of circadian photo-period disruption during pregnancy on fetal blood reproductive hormone levels is scarce. This study used ewes and their fetuses to determine the effects of circadian photo-period disruption (deprivation of darkness) on follicle-stimulating hormone, luteinizing hormone, estradiol, and progesterone in maternal and fetal circulation at late gestation. Pregnant ewes (gestational age: 135 ± 3 days) were randomly placed into control and dark deprivation groups. The control (N = 5) and dark deprivation (N = 5) groups were exposed to a fixed 12 h light/12 h dark cycle and a 24 h constant light cycle, respectively, for 2 days. Dark deprivation up-regulated follicle-stimulating hormone and estradiol levels and down-regulated progesterone levels in both maternal and fetal circulation, and up-regulated luteinizing hormone levels in fetal but not maternal circulation. These results provide new information about how circadian photo-period disruption during pregnancy could alter the release of certain reproductive hormones into fetal blood, which may influence the development of fetal organs in utero, as well as long-term health.

Exposure to nicotine during pregnancy and altered learning and memory in the rat offspring.

INTRODUCTION: Prenatal exposure to nicotine can cause many fetal developmental problems. This study determined the influence of nicotine during pregnancy on the development of cognitive behavior in the offspring. METHODS: Nicotine was administered to pregnant rats through implanted osmotic mini-pumps at 6mg/kg/day and flow rate of 60 µl/day for whole pregnancy from gestational day 4. Fetal and offspring body and brain weight was measured. Learning and memory were tested in adult offspring with Morris water maze; Learning and memory-related receptors were measured. RESULTS: The results showed that exposure to prenatal nicotine (PN) not only caused fetal growth restriction, but also had long-term effects on learning and memory in the offspring. The PN offspring exhibited longer escape latency regardless of sex. The number of passing the platform was significantly less in the PN offspring than that of the control. The expression of messenger RNA (mRNA) and protein of N-methyl-D-aspartic acid receptor (NMDAR) in the hippocampus was significantly increased, whereas alpha7 nicotinic acetylcholine receptor (α7 nAChR) protein was decreased with unchanged α7 nAChR mRNA in the PN offspring. CONCLUSION: The data provided novel information on the PN-affected development in learning and memory in the offspring, suggesting that α7 nAChR and NMDAR1 in the hippocampus might be the targets for actions of PN in association with memory impairment.

Hypoxia-induced proliferation in mesenchymal stem cells and angiotensin II-mediated PI3K/AKT pathway.

Hypoxia could stimulate proliferation of mesenchymal stem cells (MSCs) under certain conditions. This study determined angiotensin II mechanisms and PI3K/AKT pathway in hypoxia-induced proliferation of MSCs. Hypoxia (3% oxygen) induced cellular proliferation in mouse MSCs and upregulated endogenous angiotensin II and angiotensin-converting enzyme in the cell culture and expression of AT1 receptors. The expressions of Sox2, not Oct4 and Rex1, were significantly increased by the hypoxia. The blockade of AT1 receptors, not AT2 receptors, depressed hypoxia induced the proliferative effects. Both hypoxia and exogenous angiotensin II activated p-AKT. Moreover, AT1 receptor inhibitor blocked the effects of hypoxia-mediated p-AKT upregulation. The data demonstrated that the hypoxia at 3% oxygen level could induce mouse MSC proliferation, probably as a result of the activation of PI3K signalling pathways via AT1 receptors.

Prenatal Nicotine Exposure Raises Male Blood Pressure via FTO-Mediated NOX2/ROS Signaling.

BACKGROUND: Cigarette smoking/nicotine exposure in pregnancy shows an increased risk of hypertension in offspring, but the mechanisms are unclear. This study tested the hypothesis that m6A RNA hypomethylation epigenetically regulates vascular NOX (NADPH oxidase) and reactive oxygen species production, contributing to the fetal programming of a hypertensive phenotype in nicotine-exposed offspring. METHODS: Pregnant rats were exposed to episodic chronic intermittent nicotine aerosol (CINA) or saline aerosol control from gestational day 4 to day 21, and experiments were performed in 6-month-old adult offspring. RESULTS: Antenatal CINA exposure augmented Ang II (angiotensin II)-stimulated blood pressure response in male, but not female offspring. Moreover, CINA increased vascular NOX2 expression and superoxide production exclusively in male offspring. Inhibition of NOX2 with gp91ds-tat, both ex vivo and in vivo, mitigated the CINA-induced elevation in superoxide production and blood pressure response. Notably, CINA enhanced the expression of vascular m6A demethylase FTO (fat mass and obesity-associated protein), while reducing the total vascular m6A abundance and specific m6A methylation of the NOX2 gene. Additionally, ex vivo inhibition of FTO with FB23-2 attenuated CINA-induced increases in vascular NOX2 expression. In vitro experiments using human umbilical vein endothelial cells demonstrated that nicotine dose-dependently upregulated FTO and NOX2 protein abundance, which were reversed by treatment with the FTO inhibitor FB23-2 or FTO knockdown using siRNAs. CONCLUSIONS: This study uncovers a new mechanism: m6A demethylase FTO-mediated epigenetic upregulation of vascular NOX2 signaling in CINA-induced hypertensive phenotype. This insight could lead to a therapeutic target for preventing and treating developmental hypertension programming.