Insulin-dependent, glucose transporter 1 mediated glucose uptake and tube formation in the human placental first trimester trophoblast cells.

During early gestation, hypoxic condition is critically maintained by optimal glucose metabolism and transporter activities. Glucose is readily available energy nutrient required for placentation. However, limited data are available on glucose uptake and its transporters during first trimester placentation processes. To this end, effects of glucose and the roles of glucose transporters (GLUTs) were investigated during hypoxia on trophoblast migration and placental angiogenesis processes using early gestation-derived trophoblast cells, HTR8/SVneo, and first trimester human placental explant tissues. Exogenously added glucose (25 mM) significantly increased tube formation (in vitro angiogenesis) in HTR8/SVneo cells with concomitant activation of AKT-PI3K pathway and increased expression of vascular cell adhesion molecule 1 (VCAM1) compared with those in the presence of 11 mM glucose. Cobalt chloride (CoCl2)-induced hypoxia also significantly increased glucose uptake and GLUT1 expression along with tube formation and migration of HTR8/SVneo cells. During hypoxia, addition of glucose further stimulated HIF1α expression than by hypoxia alone. Cytochalasin B (cyt-B) inhibited the glucose uptake both in the presence of 11 mM and 25 mM glucose. Insulin (1 ng/ml) stimulated GLUT1 expression and tube formation and up-regulated the expression of VEGFR2 in HTR8/SVneo cells. Insulin and glucose-stimulated tube formation was inhibited by cyt-B but had no effect on hypoxia-induced tube formation. Silencing of GLUT1 inhibited the glucose and insulin-stimulated tube formation as well as glucose uptake. However, fatty acid-stimulated tube formation was not affected in GLUT1 knockdown cells. All these data suggest that glucose uptake, glucose-stimulated tube formation, and insulin-stimulated glucose uptake of the first trimester trophoblast cells, HTR8/SVneo, are mediated in part via GLUT1.

Tube formation in the first trimester placental trophoblast cells: Differential effects of angiogenic growth factors and fatty acids.

The study aims to investigate whether cytosolic fatty acid-binding protein-4 (FABP4) is involved in angiogenic growth factors- and fatty acid-induced tube formation in first trimester placental trophoblast cells, HTR8/SVneo. We determined the tube formation both at basal as well as stimulated levels in the absence and presence of inhibitors of FABP4 and VEGF signaling pathways. Basal level of tube formation was maximally reduced in the presence of 50 µM of FABP4 inhibitor compared with those by VEGF signaling pathway inhibitors (rapamycin, L-NAME, and p38 MAP kinase inhibitor). Whereas docosahexaenoic acid, 22:6n-3 (DHA)-, and VEGF-induced tube formation was maximally inhibited by p38 MAP kinase inhibitor (63.7 and 34.5%, respectively), however, leptin-induced tube formation was inhibited maximally by FABP4 inhibitor (50.7%). ANGPTL4 and oleic acid (OA)-induced tube formation was not blocked by any of these inhibitors. The FABP4 inhibitor inhibited cell growth stimulated by DHA, leptin, VEGF, and OA (P < 0.05) but was not affected by ANGPTL4. VEGF, leptin, and OA also increased FABP4 protein level in these cells, though the uptake of fatty acids by these cells was not affected by the presence of FABP4 inhibitor. Our data demonstrate that FABP4 may be involved in part in the basal level, and stimulated tube formation by VEGF, DHA, and leptin, whereas it has little or no effect in ANGPTL4- and OA-induced tube formation in these cells. Thus, FABP4 may play a differential role in fatty acids and angiogenic growth factors-mediated tube formation in the first trimester trophoblast cells in vitro.

Molecular epidemiology of hand, foot, and mouth disease in Karnataka, India in 2022.

BACKGROUND: Hand, foot, and mouth disease (HFMD) is an enteroviral disease that occurs as outbreaks and sporadic cases in India. In this study, we investigated and characterized the aetiology of HFMD cases that occurred in Karnataka, South India from April to October 2022. METHODS: Throat swabs, vesicular swabs, urine, and blood samples from suspected cases were analysed by reverse transcription polymerase chain reaction (RT-PCR) for the detection of enteroviruses. Molecular typing of the enterovirus-positive samples was carried out by amplifying the partial virion protein 1(VP1) gene sequence, followed by sequencing and phylogenetic analysis. RESULTS: Out of the 187 samples received from 82 cases, 93 (50%) tested positive (55/82 cases, 67%) for enteroviruses, with the majority of the HFMD cases reported in paediatric population of less than 5 years (36/55, 65.4%), while 3 cases (3/55, 5.4%) were adults. Out of the 55 enterovirus-positive cases, 31 showed partial VP1 region amplification and 19 of these cases were typed as coxsackievirus A16 (CV-A16) (13/19, 68.4%) and CV-A6 (6/19, 31.6%). The CV-A16 strains identified belonged to subclade B1c while two CV-A6 strains belonged to subclade E2. On molecular testing for other viruses causing fever-rash symptoms, 4/27 (15%) enterovirus-negative cases were detected as herpes simplex virus (1 case) and varicella zoster virus (3 cases) positive. CONCLUSION: The main causative agent of HFMD in Karnataka in 2022 was CV-A16, followed by CV-A6. Apart from the common paediatric HFMD cases, adult cases were also reported during this period. Further studies involving laboratory and clinical investigations are essential for monitoring and managing HFMD in the community.

Maternal dietary deficiency of n-3 fatty acids affects metabolic and epigenetic phenotypes of the developing fetus.

Polyunsaturated fatty acids (PUFAs) play multiple physiological roles. They regulate the structure and function of cell membranes and cell growth and proliferation, and apoptosis. In addition, PUFAs are involved in cellular signaling, gene expression and serve as precursors to second messengers such as eicosanoids, docosanoids etc. and regulate several physiological processes including placentation, inflammation, immunity, angiogenesis, platelet function, synaptic plasticity, neurogenesis, bone formation, energy homeostasis, pain sensitivity, stress, and cognitive functions. Linoleic acid, 18:2n-6 (LA) and alpha-linolenic acid, 18:3n-3 (ALA) are the two essential fatty acids obtained from the diets and subsequently their long-chain polyunsaturated fatty acids (LCPUFAs) are accumulated in the body. The maternal plasma LCPUFAs especially accumulated in larger amounts in the brain during the third trimester of pregnancy via the placenta and postnatally from mother's breast milk. Various studies, including ours, suggest PUFA's important role in placentation, as well as in growth and development of the offspring. However, intakes of maternal n-3 PUFAs during pregnancy and lactation are much lower in India compared with the Western population. In India, n-3 fatty acid status is further reduced by higher intake of n-6 PUFA rich oils and trans fats. More data on the impacts of long term maternal n-3 PUFA deficiency on placental structure and function, gene expression, epigenetic changes and resultant cognitive function of fetus & infants are emerging. This review summarizes the impacts of n-3 PUFA deficiency in utero on fetal growth and development, adiposity, energy metabolism, musculoskeletal development, and epigenetic changes in feto-placental axis from the recently available pre-clinical and clinical data.