ORCID Profile
0000-0001-9513-181X
Current Organisation
University of South Australia
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Publisher: Elsevier BV
Date: 03-2021
Publisher: American Physiological Society
Date: 03-2007
DOI: 10.1152/AJPENDO.00320.2006
Abstract: Appropriate partitioning of nutrients between the mother and conceptus is a major determinant of pregnancy success, with placental transfer playing a key role. Insulin-like growth factors (IGFs) increase in the maternal circulation during early pregnancy and are predictive of fetal and placental growth. We have previously shown in the guinea pig that increasing maternal IGF abundance in early to midpregnancy enhances fetal growth and viability near term. We now show that this treatment promotes placental transport to the fetus, fetal substrate utilization, and nutrient partitioning near term. Pregnant guinea pigs were infused with IGF-I, IGF-II (both 1 mg·kg −1 ·day −1 ) or vehicle subcutaneously from days 20–38 of pregnancy (term = 69 days). Tissue uptake and placental transfer of the nonmetabolizable radio analogs [ 3 H]methyl-d-glucose (MG) and [ 14 C]aminoisobutyric acid (AIB) in vivo was measured on day 62. Early pregnancy exposure to elevated maternal IGF-I increased placental MG uptake by % ( P = 0.004), whereas each IGF increased fetal plasma MG concentrations by 40–50% ( P 0.012). Both IGFs increased fetal tissue MG uptake ( P 0.048), whereas IGF-I also increased AIB uptake by visceral organs ( P = 0.046). In the mother, earlier exposure to either IGF increased AIB uptake by visceral organs ( P 0.014), whereas IGF-I also enhanced uptake of AIB by muscle ( P = 0.044) and MG uptake by visceral organs ( P = 0.016) and muscle ( P = 0.046). In conclusion, exogenous maternal IGFs in early pregnancy sustainedly increase maternal substrate utilization, placental transport of MG to the fetus, and fetal utilization of substrates near term. This was consistent with the previously observed increase in fetal growth and survival following IGF treatment.
Publisher: Oxford University Press (OUP)
Date: 11-2012
DOI: 10.1095/BIOLREPROD.112.100222
Abstract: Growth hormone (GH) is important in maternal adaptation to pregnancy, and maternal circulating GH concentrations are reduced in human growth-restricted pregnancies. In the pig, maternal GH treatment throughout early to mid pregnancy increases fetal growth, despite constraining effects of adolescent and primiparous pregnancy, high litter size, and restricted maternal nutrition. Because GH cannot cross the placenta and does not increase placental weight, we hypothesized that its effects on fetal growth might be via improved placental structure or function. We therefore investigated effects of maternal GH treatment in pigs on structural correlates of placental function and placental expression of nutrient transporters important to fetal growth. Multiparous (sows) and primiparous pregnant pigs (gilts) were treated with GH (~15 μg kg(-1) day(-1)) or vehicle from Days 25-50 of gestation (n = 7-8 per group, term ~115 days). Placentas were collected at Day 50 of gestation, and we measured structural correlates of function and expression of SLC2A1 (previously known as GLUT1) and SLC38A2 (previously known as SNAT2) nutrient transporters. Maternal GH treatment did not alter placental size or structure, increased protein expression of SLC2A1 in trophoblast (+35% P = 0.037) and on its basal membrane (+44% P = 0.011), and increased SLC38A2 protein expression in the basal (+44% P = 0.001) but not the apical cytoplasm of trophoblast. Our findings suggest that maternal GH treatment increases fetal growth, in part, by enhancing placental nutrient transporter protein expression and hence fetal nutrient supply as well as trophoblast proliferation and differentiation and may have the potential to ameliorate intrauterine growth restriction.
Publisher: Cambridge University Press (CUP)
Date: 15-05-2017
DOI: 10.1017/S2040174417000381
Abstract: Low birth weight is associated with increased risk of cardiovascular disease in adulthood. Intrauterine growth restriction (IUGR) hearts have fewer CMs in early postnatal life, which may impair postnatal cardiovascular function and hence, explain increased disease risk, but whether the cardiomyocyte deficit persists to adult life is unknown. We therefore studied the effects of experimentally induced placental restriction (PR) on cardiac outcomes in young adult sheep. Heart size, cardiomyocyte number, nuclearity and size were measured in control ( n =5) and PR ( n =5) male sheep at 1 year of age. PR lambs were 36% lighter at birth ( P =0.007), had 38% faster neonatal relative growth rates ( P =0.001) and had 21% lighter heart weights relative to body weight as adults ( P =0.024) than control lambs. Cardiomyocyte number, nuclearity and size in the left ventricle did not differ between control and PR adults hearts of both groups contained cardiomyocytes (CM) with between one and four nuclei. Overall, cardiomyocyte number in the adult left ventricle correlated positively with birth weight but not with adult weight. This study is the first to demonstrate that intrauterine growth directly influences the complement of CM in the adult heart. Cardiomyocyte size was not correlated with cardiomyocyte number or birth weight. Our results suggest that body weight at birth affects lifelong cardiac functional reserve. We hypothesise that decreased cardiomyocyte number of low birth weight in iduals may impair their capacity to adapt to additional challenges such as obesity and ageing.
Publisher: American Physiological Society
Date: 2018
DOI: 10.1152/AJPREGU.00549.2016
Abstract: Perinatal exposures are associated with altered risks of childhood allergy. Human studies and our previous work suggest that restricted growth in utero (IUGR) is protective against allergic disease. The mechanisms are not clearly defined, but reduced fetal abundance and altered metabolism of methyl donors are hypothesized as possible underlying mechanisms. Therefore, we examined whether late-gestation maternal dietary methyl donor and cofactor supplementation of the placentally restricted (PR) sheep pregnancy would reverse allergic protection in progeny. Allergic outcomes were compared between progeny from control pregnancies (CON n = 49), from PR pregnancies without intervention (PR n = 28), and from PR pregnancies where the dam was fed a methyl donor plus cofactor supplement from day 120 of pregnancy until delivery (PR + Methyl n = 25). Both PR and PR + Methyl progeny were smaller than CON supplementation did not alter birth size. PR was protective against cutaneous hypersensitivity responses to ovalbumin (OVA P 0.01 in singletons). Cutaneous hypersensitivity responses to OVA in PR + Methyl progeny were intermediate to and not different from the responses of CON and PR sheep. Cutaneous hypersensitivity responses to house dust mites did not differ between treatments. In singleton progeny, upper dermal mast cell density was greater in PR + Methyl than in PR or CON (each P 0.05). The differences in the cutaneous allergic response were not explained by treatment effects on circulating immune cells or antibodies. Our results suggest that mechanisms underlying in utero programming of allergic susceptibility by IUGR and methyl donor availability may differ and imply that late-gestation methyl donor supplementation may increase allergy risk.
Publisher: American Physiological Society
Date: 04-2014
DOI: 10.1152/AJPREGU.00432.2013
Abstract: Prenatal and early childhood exposures are implicated as causes of allergy, but the effects of intrauterine growth restriction on immune function and allergy are poorly defined. We therefore evaluated effects of experimental restriction of fetal growth on immune function and allergic sensitization in adolescent sheep. Immune function (circulating total red and white blood cells, neutrophils, lymphocytes, monocytes, eosinophils, and basophils, and the antibody response to Clostridial vaccination) and responses to house dust mite (HDM) allergen and ovalbumin (OVA) antigen sensitization (specific total Ig, IgG 1 , and IgE antibodies, and cutaneous hypersensitivity) were investigated in adolescent sheep from placentally restricted (PR, n = 23) and control ( n = 40) pregnancies. Increases in circulating HDM-specific IgE ( P = 0.007) and OVA-specific IgE ( P = 0.038) were greater in PR than control progeny. PR did not alter total Ig, IgG 1 , or IgM responses to either antigen. PR increased OVA-specific but not HDM-specific IgA responses in females only ( P = 0.023). Multiple birth increased Ig responses to OVA in a sex-specific manner. PR decreased the proportion of positive cutaneous hypersensitivity responders to OVA at 24 h ( P = 0.030) but had no effect on cutaneous responses to HDM. Acute wheal responses to intradermal histamine correlated positively with birth weight in singletons ( P = 0.023). Intrauterine growth restriction may suppress inflammatory responses in skin downstream of IgE induction, without impairment in antibody responses to a nonpolysaccharide vaccine. Discord between cutaneous and IgE responses following sensitization suggests new mechanisms for prenatal allergy programming.
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.PLACENTA.2012.04.003
Abstract: There is inconsistent use of Matrigel for experiments with the HTR8/SVneo first trimester trophoblast and other cell lines. We quantified the effects of Matrigel on the expression of genes considered to be markers of extravillous cytotrophoblast (EVT) differentiation and invasive potential. Culture on Matrigel promoted formation of "endothelial-like" tubes and reduced mRNA expression of matrix metalloproteinase 2 (MMP2), cytokeratin 7 (KRT7) and integrin alpha 1 (ITGA1), while increasing VE-cadherin (CDH5) expression consistent with a vascular phenotype. This process may constitute part of the endothelial cell mimicry exhibited by endovascular EVTs invading the maternal spiral arteries. HTR8/SVneo appears to be phenotypically polymorphic and adopt endovascular morphology on Matrigel.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Bioscientifica
Date: 09-2014
DOI: 10.1530/EC-14-0068
Abstract: Circulating IGFs are important regulators of prenatal and postnatal growth, and of metabolism and pregnancy, and change with sex, age and pregnancy. Single-nucleotide polymorphisms (SNPs) in genes coding for these hormones associate with circulating abundance of IGF1 and IGF2 in non-pregnant adults and children, but whether this occurs in pregnancy is unknown. We therefore investigated associations of plasma IGF1 and IGF2 with age and genotype at candidate SNPs previously associated with circulating IGF1, IGF2 or methylation of the INS – IGF2 – H19 locus in men ( n =134), non-pregnant women ( n =74) and women at 15 weeks of gestation ( n =98). Plasma IGF1 concentrations decreased with age ( P .001) and plasma IGF1 and IGF2 concentrations were lower in pregnant women than in non-pregnant women or men (each P .001). SNP genotypes in the INS – IGF2 – H19 locus were associated with plasma IGF1 ( IGF2 rs680, IGF2 rs1004446 and IGF2 rs3741204) and IGF2 ( IGF2 rs1004446, IGF2 rs3741204 and H19 rs217727). In single SNP models, effects of IGF2 rs680 were similar between groups, with higher plasma IGF1 concentrations in in iduals with the GG genotype when compared with GA ( P =0.016), or combined GA and AA genotypes ( P =0.003). SNPs in the IGF2 gene associated with IGF1 or IGF2 were in linkage disequilibrium, hence these associations could reflect other genotype variations within this region or be due to changes in INS – IGF2 – H19 methylation previously associated with some of these variants. As IGF1 in early pregnancy promotes placental differentiation and function, lower IGF1 concentrations in pregnant women carrying IGF2 rs680 A alleles may affect placental development and/or risk of pregnancy complications.
Publisher: Springer Science and Business Media LLC
Date: 09-02-2022
DOI: 10.1038/S42003-022-03020-9
Abstract: Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum . Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1 . We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to a proportion of merozoites failing to invade and was associated with elongation of the rhoptry organelle during merozoite development and inhibition of rhoptry antigen processing. These findings identify PfCERLI2 as a protein that has key roles in rhoptry biology during merozoite invasion.
Publisher: Wiley
Date: 13-03-2022
DOI: 10.1111/IMCB.12539
Abstract: The ongoing coronavirus disease 2019 (COVID‐19) pandemic perpetuated by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) variants has highlighted the continued need for broadly protective vaccines that elicit robust and durable protection. Here, the vaccinia virus‐based, replication‐defective Sementis Copenhagen Vector (SCV) was used to develop a first‐generation COVID‐19 vaccine encoding the spike glycoprotein (SCV‐S). Vaccination of mice rapidly induced polyfunctional CD8 T cells with cytotoxic activity and robust type 1 T helper‐biased, spike‐specific antibodies, which are significantly increased following a second vaccination, and contained neutralizing activity against the alpha and beta variants of concern. Longitudinal studies indicated that neutralizing antibody activity was maintained up to 9 months after vaccination in both young and middle‐aged mice, with durable immune memory evident even in the presence of pre‐existing vector immunity. Therefore, SCV‐S vaccination has a positive immunogenicity profile, with potential to expand protection generated by current vaccines in a heterologous boost format and presents a solid basis for second‐generation SCV‐based COVID‐19 vaccine candidates incorporating additional SARS‐CoV‐2 immunogens.
Publisher: MDPI AG
Date: 22-02-2022
Abstract: Mutations in FMS-like tyrosine kinase 3 (FLT3) occur in approximately one-third of AML patients and are associated with a particularly poor prognosis. The most common mutation, FLT3-ITD, is a self-activating internal tandem duplication (ITD) in the FLT3 juxtamembrane domain. Many FLT3 inhibitors have shown encouraging results in clinical trials, but the rapid emergence of resistance has severely limited sustainable efficacy. Co-targeting of CDK9 and FLT3 is a promising two-pronged strategy to overcome resistance as the former plays a role in the transcription of cancer cell-survival genes. Most prominently, MCL-1 is known to be associated with AML tumorigenesis and drug resistance and can be down-regulated by CDK9 inhibition. We have developed CDDD11-8 as a potent CDK9 inhibitor co-targeting FLT3-ITD with Ki values of 8 and 13 nM, respectively. The kinome selectivity has been confirmed when the compound was tested in a panel of 369 human kinases. CDDD11-8 displayed antiproliferative activity against leukemia cell lines, and particularly potent effects were observed against MV4-11 and MOLM-13 cells, which are known to harbor the FLT3-ITD mutation and mixed lineage leukemia (MLL) fusion proteins. The mode of action was consistent with inhibition of CDK9 and FLT3-ITD. Most importantly, CDDD11-8 caused a robust tumor growth inhibition by oral administration in animal xenografts. At 125 mg/kg, CDDD11-8 induced tumor regression, and this was translated to an improved survival of animals. The study demonstrates the potential of CDDD11-8 towards the future development of a novel AML treatment.
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.GHIR.2015.02.001
Abstract: Insulin-like growth factors (IGFs) are known to interact with the renin-angiotensin system (RAS). We previously demonstrated that administration of IGF1 to guinea pigs in early to mid pregnancy promotes placental function and fetal growth in mid to late gestation. Early administration of IGF2 had sustained, but not acute, effects on these parameters and also on placental structural differentiation. Here, we aimed to determine whether the IGFs interact with the placental RAS in early to mid gestation to modulate placental development and increase fetal growth and survival, and if IGF2 binding the IGF2R is implicated in the sustained effects of IGF2 treatment. At day 20 of pregnancy, guinea pigs were infused with 1m g/kg/day of IGF1, IGF2, (Leu27)IGF2 or vehicle for 18days and sacrificed on either day 62 (late pregnancy) or during the infusion period on day 35 (early-mid pregnancy). Placental structure at day 35 was analyzed using morphometric technique and expression of RAS genes in the placenta and placental and plasma renin activity were measured at both time points. Compared with vehicle at day 35 of gestation, IGF1 infusion reduced the total midsagittal cross-sectional area of the placenta (-17%, p = 0.02) and the labyrinth area (-22%, p = 0.014) but did not alter the labyrinth volume nor labyrinth:interlobium ratios. IGF2 treatment did not affect placental structure. IGF1 did not alter placental mRNA for any of the RAS genes quantified at day 35 (AGTR1, ACE, AGT, TGFB1) but increased TGFB1 expression by more than 16-fold (p = 0.005) at day 62. IGF2 increased placental expression of AGTR1 (+88%, p = 0.03) and decreased AGT (-73%, p = 0.01) compared with the vehicle-treated group at day 35, and both IGF2 and (Leu27)IGF2 increased expression of TGFB1 at day 62 by 9-fold (p = 0.016) and 6-fold (p = 0.019) respectively. Both IGFs increased the ratio of active:total placental renin protein (+22% p = 0.026 p = 0.038) compared to vehicle compared to vehicle at day 35 but not 62. At day 62, IGF2-treated mothers showed a marked increase in total plasma renin (+495%) and active renin (+359%) compared to vehicle but decreased the ratio of active to total renin by 41% (p = 0.042). (Leu27)IGF2-treated animals had higher levels of placental active renin (+73%, p = 0.001) and total renin (+71%, p = 0.001) compared with the vehicle control. The data obtained in the current study suggest the potential for alternate roles for the induction of the RAS after IGF treatment. IGF1 and 2 treatments increase the activation of prorenin to renin in the placenta, possibly due to increased protease activity. In addition, IGF2 treatment in early pregnancy may enhance the maternal adaptation to pregnancy through stimulation of renin in the kidney. The sustained effects on placental differentiation and function after IGF2 treatment suggest therapeutic potential for exogenous administration of IGFs in improving pregnancy outcomes.
Publisher: American Physiological Society
Date: 15-09-2015
DOI: 10.1152/AJPENDO.00487.2014
Abstract: Intrauterine growth restriction (IUGR) increases the risk of adult type 2 diabetes (T2D) and obesity. Neonatal exendin-4 treatment can prevent diabetes in the IUGR rat, but whether this will be effective in a species where the pancreas is more mature at birth is unknown. Therefore, we evaluated the effects of neonatal exendin-4 administration after experimental restriction of placental and fetal growth on growth and adult metabolic outcomes in sheep. Body composition, glucose tolerance, and insulin secretion and sensitivity were assessed in singleton-born adult sheep from control (CON n = 6 females and 4 males) and placentally restricted pregnancies (PR n = 13 females and 7 males) and in sheep from PR pregnancies that were treated with exendin-4 as neonates (daily sc injections of 1 nmol/kg exendin-4 PR + exendin-4 n = 11 females and 7 males). Placental restriction reduced birth weight (by 29%) and impaired glucose tolerance in the adult but did not affect adult adiposity, insulin secretion, or insulin sensitivity. Neonatal exendin-4 suppressed growth during treatment, followed by delayed catchup growth and unchanged adult adiposity. Neonatal exendin-4 partially restored glucose tolerance in PR progeny but did not affect insulin secretion or sensitivity. Although the effects on glucose tolerance are promising, the lack of effects on adult body composition, insulin secretion, and insulin sensitivity suggest that the neonatal period may be too late to fully reprogram the metabolic consequences of IUGR in species that are more mature at birth than rodents.
Publisher: Springer Science and Business Media LLC
Date: 16-03-2020
DOI: 10.1038/S41467-020-15127-W
Abstract: The disease-causing blood-stage of the Plasmodium falciparum lifecycle begins with invasion of human erythrocytes by merozoites. Many vaccine candidates with key roles in binding to the erythrocyte surface and entry are secreted from the large bulb-like rhoptry organelles at the apical tip of the merozoite. Here we identify an essential role for the conserved protein P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 1 (PfCERLI1) in rhoptry function. We show that PfCERLI1 localises to the cytosolic face of the rhoptry bulb membrane and knockdown of PfCERLI1 inhibits merozoite invasion. While schizogony and merozoite organelle biogenesis appear normal, biochemical techniques and semi-quantitative super-resolution microscopy show that PfCERLI1 knockdown prevents secretion of key rhoptry antigens that coordinate merozoite invasion. PfCERLI1 is a rhoptry associated protein identified to have a direct role in function of this essential merozoite invasion organelle, which has broader implications for understanding apicomplexan invasion biology.
Publisher: Wiley
Date: 10-2021
DOI: 10.1002/HSR2.410
Publisher: Oxford University Press (OUP)
Date: 23-04-2013
No related grants have been discovered for Gary Heinemann.