Parent of origin influences the cardiac expression of vascular endothelial growth factor (Vegfa)

A bioinformatics approach for identifying potential molecular mechanisms and key genes involved in COVID-19 associated cardiac remodeling

In 2019 coronavirus disease (COVID-19), whose main complication is respiratory involvement, different organs may also be affected in severe cases. However, COVID-19 associated cardiovascular manifestations are limited at present. The main purpose of this study was to identify potential candidate genes involved in COVID-19-associated heart damage by bioinformatics analysis. Differently expressed genes (DEGs) were identified using transcriptome profiles (GSE150392 and GSE4172) downloaded from the GEO database. After gene and pathway enrichment analyses, PPI network visualization, module analyses, and hub gene extraction were performed using Cytoscape software. A total of 228 (136 up and 92 downregulated) overlapping DEGs were identified at these two microarray datasets. Finally, the top hub genes (FGF2, JUN, TLR4, and VEGFA) were screened out as the critical genes among the DEGs from the PPI network. Identification of critical genes and mechanisms in any disease can lead us to better diagnosis and targeted therapy. Our findings identified core genes shared by inflammatory cardiomyopathy and SARS-CoV-2. The findings of the current study support the idea that these key genes can be used in understanding and managing the long-term cardiovascular effects of COVID-19.

Effect of placental growth factor in models of experimental pre-eclampsia and trophoblast invasion

Placental growth factor (PlGF) is decreased in early gestation of pregnant women who subsequently develop pre-eclampsia. In this study, pre-emptive treatment with PlGF to prevent pre-eclampsia was evaluated in an in vivo rodent model of experimental pre-eclampsia (EPE) induced by TNF-α and in an in vitro model of human first-trimester trophoblast invasion. Pregnant C57/BL6 mice were treated with recombinant mouse placental growth factor-2 (rmPlGF-2) 100 μg/kg/day IP from gestational day (gd) 10. Animals had EPE induced by continuous TNF-α infusion on gd 13 and were subject to either continuous blood pressure monitoring by radiotelemetry throughout pregnancy or live placenta T₂ -weighted magnetic resonance imaging (MRI) to demonstrate placental function on gd 17. There was no difference in BP (P > .99), proteinuria (P = .9) or T₂ values on MRI (P = .9) between control and rmPlGF-2-treated animals. On gd 13, animals treated with rmPlGF-2 demonstrated increased placenta PlGF (P = .01) and Toll-like receptor-3 (P = .03) mRNA expression as compared with controls. Fluorescent-labelled human uterine microvascular endothelial cells and HTR8/SVNeo cells were co-cultured on Matrigel^™ and treated with recombinant human PlGF (rhPlGF) (10 ng/mL) and/or TNF-α (0.5 ng/mL). Trophoblast integration into endothelial networks was reduced by added TNF-α (P = .006), as was rhPlGF concentration in conditioned media (P < .0001). Cell integration was not ameliorated by addition of rhPlGF (P > .9). Although TNF-α-induced EPE was not reversed with pre-emptive rmPlGF-2, a further trial of pre-emptive rhPlGF in vivo is required to determine whether the absence of effect of rhPlGF demonstrated in vitro precludes PlGF as a preventative therapy for pre-eclampsia.

Comparative analysis of basal locomotor activity-related metabolic phenotypes between C57BL/6 mice and ICR mice substrains derived from three different sources

Animal model, as an indispensable tool for scientific purposes of biomedical researches and clinical application, is a commonly used in various researches. Regarding to this, it is necessary to establish the metabolic phenotype of animal model to minimize spurious interpretations and ensure a level of accuracy and reliability adequate for experimental research. However, the metabolic phenotype-related analysis within rodent strains derived from different source is nonexistent, especially in C57BL/6Korl mice and Korl:ICR mice (a domestic mouse strain). To compare the physiological and metabolic phenotypes over a period of time, we utilized the C57BL/6 mice (C57BL/6Korl, A:C57BL/6, and B:C57BL/6) and ICR mice (Korl:ICR, A:ICR, and B:ICR) derived from three different sources. Our data showed that average body weight, body temperature, food intake, and water consumption have a similar tendency among the C57BL/6 and ICR groups, except for the higher body weight of C57BL/6Korl mice over a period of time. Moreover, some significant differences was observed in adipose tissue mass and adipocyte size among the groups, with a higher tendency of C57BL/6Korl mice and Korl:ICR mice. Most importantly, resting metabolic rate (RMR) serves as an approximation of the metabolic phenotype showed no significant difference among the groups of C57BL/6 mice and ICR mice, except for the lower oxygen uptake of C57BL/6Korl mice compare to the A:C57BL/6 mice. Taken together, our data suggest that C57BL/6 mice and ICR mice derived from three different sources have an overall similar feature of physiological and metabolic phenotypes.

Gene expression of vascular endothelial growth factor A and hypoxic adaptation in Tibetan pig

Background

Vascular endothelial growth factor A (VEGFA) can induce endothelial cell proliferation, promote cell migration, and inhibit apoptosis. These processes play key roles in physiological blood vessel formation and pathological angiogenesis.

Methods

In this study, we examined VEGFA gene expression in the heart, liver, and kidney of Tibetan pigs (TP), Yorkshire pigs that migrated to high altitudes (YH), and Yorkshire pigs that lived at low altitudes (YL). We used PCR and Sanger sequencing to screen for single nucleotide polymorphisms (SNPs) in 5ʹ-flanking DNA and exons of the VEGFA gene. Quantitative real-time PCR and western blots were used to measure expression levels and PCR products were sequenced.

Results

Results showed that the VEGFA mRNA and protein expression in heart, liver and kidney of TP was higher than that in YH and YL. In addition, the mRNA sequence of the pig VEGFA gene was conserved among pig breeds, and only five SNPs were found in the 5ʹ-flanking region of the VEGFA gene, the allele frequency distributions of the 5 SNPs were not significantly different between the TP, Yorkshire (YL), and Diannan small-ear (DN) pig populations.

Conclusion

In conclusion, the Tibetan pig showed high levels of VEGFA gene expression in several hypoxic tissues, which suggests that the VEGFA gene may play a major functional role in hypoxic adaptation.

Placental Regulation of Inflammation and Hypoxia after TNF-α Infusion in Mice

PROBLEM

Increased levels of inflammatory cytokines are demonstrated in the serum of women with pre-eclampsia. TNF-α infusion in animal models induces proteinuric hypertension similar to human pre-eclampsia. The effect of TNF-α on regulation of the immune and hypoxic pathways in the developing placenta and their relationship with experimental pre-eclampsia remains unexamined.

METHOD OF STUDY

TNF-α was infused into pregnant mice, and the effects on maternal hypertension, proteinuria, circulating levels of sFlt-1 and corresponding placental changes in molecules responding to inflammation (TLR-3 and TLR-4) and hypoxia (HIF-1α) were examined.

RESULTS

TNF-α infusion resulted in maternal hypertension and proteinuria. Molecular changes in the placenta involved upregulation of TLR-3, TLR-4 and HIF-1α. Serum levels of sFlt-1 were high in pregnant animals, but not further upregulated by TNF-α infusion.

CONCLUSION

A role for maladaptive regulation of TLR and HIF-1α induced by an imbalance in inflammatory cytokines is implicated in the pathogenesis of pre-eclampsia.

Identification of genes with altered expression in male and female Schlager hypertensive mice

Background

Numerous studies have shown sex differences in the onset and severity of hypertension. Despite these sex-differences the majority of animal studies are carried out in males. This study investigated expression changes in both male and female hypertensive mouse kidneys to identify common mechanisms that may be involved in the development of hypertension.

Methods

The Schlager hypertensive mouse model (BPH/2J) and its normotensive control (BPN/3J) were used in this study. Radiotelemetry was performed on 12 to 13 week old BPH/2J and BPN/3J male and female animals. Affymetrix GeneChip Mouse Gene 1.0 ST Arrays were performed in kidney tissue from 12 week old BPH/2J and BPN/3J male and female mice (n = 6/group). Genes that were differentially expressed in both male and female datasets were validated using qPCR.

Results

Systolic arterial pressure and heart rate was significantly higher in BPH/2J mice compared with BPN/3J mice in both males and females. Microarray analysis identified 153 differentially expressed genes that were common between males and females (70 upregulated and 83 downregulated). We validated 15 genes by qPCR. Genes involved in sympathetic activity (Hdc, Cndp2), vascular ageing (Edn3), and telomere maintenance (Mcm6) were identified as being differentially expressed between BPH/2J and BPN/3J comparisons. Many of these genes also exhibited expression differences between males and females within a strain.

Conclusions

This study utilised data from both male and female animals to identify a number of genes that may be involved in the development of hypertension. We show that female data can be used to refine candidate genes and pathways, as well as highlight potential mechanisms to explain the differences in prevalence and severity of disease between men and women.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-014-0101-x) contains supplementary material, which is available to authorized users.