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Sirtuins have received widespread attention due to their diverse physiological role in metabolism. Among sirtuins, SIRT2 is more abundant in adipocytes and exerts effects on adipocyte differentiation, a process which involves conversion of preadipocytes to mature adipocytes orchestrated by adipokines and adipogenic transcription factors. Grey mullet (Mugil cephalus) was chosen as a study organism due to its excellent service as a biomonitor. Adipocytes isolated from natural field conditions were termed as field-hypoxic (Ennore) and -normoxic (Kovalam) based on dissolved oxygen (DO) level in the estuary. A previous study portrayed the hypoxic instance of Ennore estuary (low DO) and grey mullet [HIF1α in adipocytes, brain endothelial cell (EC) and hepatocytes] inhabiting this estuary ( Padmini et al., 2016a, b; Padmini and Tharani, 2015). In this context, fish adipocytes of both conditions were subjected to in vitro hypoxia for 1 h (in the pre/trigassed incubator with the supply of 1% O2; 94% N2; 5% CO2) and were analysed for the expression of adipokines, adipogenic transcription factors and anti-adipogenic markers in fish adipocytes. Elevation of asymmetric dimethylarginine (ADMA), TNFα and leptin along with decreased adiponectin, adipogenic transcription factors and altering sirtuins were observed in test adipocytes and in control adipocytes on in vitro hypoxia. This suggests that adipocytes may follow internal caloric restriction as portrayed from cytomorphological/ultrastructural analysis, limiting adipocyte maturation process, one of the adaptive mechanisms triggered by adipocyte of fish surviving in Ennore estuary. Prolonged exposure to hypoxia (test on in vitro hypoxia for 1 h) showed a drastic alteration in these components leading to both structural and biological fluctuation when compared to limited hypoxic condition (field-hypoxic and control on in vitro hypoxia). Our study concludes that hypoxia may serve as the chief molecular cue in eliciting adipocyte maturation restriction though metabolic reprogramming and it also shows the significance of adipocyte maturation restriction in imparting survival mechanism., Summary: Adipocyte maturation restriction is tightly regulated by SIRT2 activation which downregulates preadipocytes from the maturation process as adaptation strategy in fish surviving in the polluted (hypoxic) environment.

Xenobiotics are synthetic compounds foreign to the biological system. They often retain their qualities in the aquatic environment with the ability to cause oxidative stress in these organisms by activating the endogenous production of reactive oxygen species (ROS). Overloading of the estuaries with contaminants for a longer period has an impact on fish production. The grey mullet (Mugil cephalus) is capable of concentrating contaminants and is considered suitable for biomarker studies. Brain is an appropriate organ for the study of the effects of xenobiotics due to its morphological heterogeneity, metal accumulating capacity and susceptibility to histopathological damage by metals. Cells respond to stress in a variety of ways by activation of pathways that promote survival or apoptosis. Hence the present study aimed at understanding the effect of pollutants on fish brain by assessing stress markers (LHP, Trx) and signalling proteins (HIF1α, HSP70, CYP1A2 and ASK-1). The changes in the biomolecular composition was assessed using Fourier Transform Infrared Spectroscopy (FTIR). A significant increase in LHP and Trx reveals pollutant induced oxidative stress. An alteration in the functional groups of lipid and proteins were identified by FTIR. A variation in the expression of HIF1α and CYP1A2 infers xenobiotic induced stress. A significant elevation in the level of HSP 70 and insignificant increase in the level of ASK-1 depicts the prime role of HSP 70. Thus the present study concludes that upregulation of HSP70 plays a cytoprotective role during xenobiotic induced stress in fish brain.

Heme oxygenase-1 (HO-1), an inducible stress protein; is involved in the regulation of adipogenesis, cellular bioenergetics and cytoprotective mechanism against hypoxia induced oxidative stress. Polluted aquatic environment leads to large oxygen fluctuations which may cause alteration in fish adaptation mechanism by HIF1α regulation. Environmental pollutants have a high tendency to accumulate, persist and bio-concentrate in adipocytes due to its lipophilic nature which ultimately causes adipocytes hypoxia that in turn affects metabolic energy balance. CYP1A2 and HO-1 are the chief detoxifying and cytoprotective enzymes involved in the oxidative metabolism of a wide variety of pollutants and its mediated cytotoxic products. The key role of hypoxia and its mediated signaling protein changes in fish adipocytes due to low dissolved oxygen in Ennore estuary was demonstrated in our previous work. Therefore, we analyzed the effect of pollutants induced hypoxia by assessing CD, HNE, TAC, G3PDH, ATP, HIF1α, HO-1 and CYP1A2 in fish adipocytes of control/unpolluted site and test/polluted site. Increase in CD, HNE, HIF1α, HO-1 along with a decrease in TAC, G3PDH, ATP and CYP1A2 observed in test adipocytes. From the results achieved, it shows that induction of HO-1 by HIF1α is crucial in maintaining the cell integrity to secure adipocytes and its maturation in the fish collected from the hypoxic environment. This study also highlights the role of HIF1α and HO-1 in regulating the expression of CYP1A2 during pollutants induced hypoxic condition.

Background: Betle leaf (BL) is an ancient herb with a potential nontoxic natural antioxidant efficacy. Oral intake and chewing betel leaves have an effort on the moving parts of salivary gland and induce salivation and detoxification; hence plays a vital role in oral hygiene. BL produces and activates various salivary enzymes which include α-amylase, lipase, lysozyme, and lactoperoxidase. BL possess antibacterial, antioxidant, anti-diabetic, immunomodulatory, and antihypertensive properties. Hence, it can be effective in the treatment of hypertensive disorder of pregnancy like preeclampsia (PE). Objective: In this context, two extracts of BL (Salivary BL extract [SBLE] and diastase BL extract [DBLE]), proved to impart efficient radical scavenging activity in our previous research work were utilized to analyze their efficacy on the level of 4-hydroxy nonenal (4-HNE), heme oxygenase-1 (HO-1), asymmetric dimethylarginine (ADMA), adiponectin/leptin in the trophoblast isolated from placental tissue of both normotensive and preeclamptic patients. Materials and Methods: Trophoblasts were isolated from both subjects and incubated with different extracts of Piper betle (saliva and diastase) to assess the cellular stress in placental trophoblast during PE. Results: Results demonstrate that extracts of BL exhibit a significant role in regulating 4-HNE, ADMA, leptin, HO-1, and adiponectin in preeclamptic trophoblasts. Still, SBLE showed relatively higher efficiency in defining the level of 4-HNE, ADMA, leptin, HO-1, and adiponectin in preeclamptic trophoblasts than DBLE, suggesting that it may be attributed to the interaction of the phytochemicals present in BL with the components of saliva. Conclusion: Hence, BL may be recommended as the effective natural remedy in the management of pathological complications of PE; which may preclude low birthweight babies and ensure live fetal delivery. Abbreviations Used: 4-HNE: 4-hydroxy-nonenal, ADMA: Asymmetric dimethylarginine, BL: Betel leaf, BLE: Betel leaf extract, CO: Carbon monoxide, DB: Diastase with betel leaf, DBLE: Diastase betel leaf extract, ELISA: Enzyme-linked immunosorbent assay, eNOS: Endothelial nitric oxide synthase, FBS: Fetal bovine serum, GSH: Reduced glutathione, HBSS: Hank's balanced salt solution, HO-1: Heme oxygenase-1, iNOS: Inducible nitric oxide synthase, NO: Nitric oxide, NOS: Nitric oxide synthase, PE: Preeclampsia, ROS: Reactive oxygen species, SB: Saliva with betel leaf, SBLE: Salivary betel leaf extract.

The brain requires constant oxygen supply to perform its biological functions essential for survival. Because of low oxygen capacity and poor oxygen diffusibility of water, many fish species have evolved various adaptive mechanisms to cope with depleted oxygen. Endothelial cells (EC) are the primary components responsible for controlled environment of brain. Brain homeostasis largely depends on integrity of the EC. To elucidate their adaptive strategy, EC were isolated from the fish brain of Kovalam-control site and Ennore estuary-test/field hypoxic site and were subjected to low oxygen tension in laboratory. Cell viability, 4-hydroxynonenal (4HNE) and total antioxidant capacity (TAC) were analyzed to ascertain stress. Hypoxic insult, cytoprotective role of HSPs and apoptotic effect were analyzed by assessing hypoxia-inducible-factor-α (HIF1α), heat-shock-protein-70 (HSP70), heme-oxygenase 1 (HO-1), and apoptosis signal regulating kinase-1 (ASK1). This study evidenced that HSP70 and HO-1 are the key stress proteins, confer high tolerance to decreased oxygen tension mediated stress.

To evaluate the effect of genistein supplementation on the oxidative/nitrative stress and antioxidant capacity of normotensive and preeclamptic placental trophoblast.The stress status of placental trophoblast was assessed by measuring their respective markers before and after incubation with genistein.A significant increase in stress along with decrease in antioxidant status was observed in preeclamptic placental trophoblast, whereas genistein incubation significantly alters oxidant-antioxidant status.The study revealed that genistein may play a significant role in controlling oxidative/nitrative stress during preeclampsia. Hence, genistein can be used as an effective dietary supplement for the treatment and management of preeclampsia.

Worldwide, the frequencies and magnitudes of hypoxic events in estuarine waters have increased considerably over the past two decades. Fish populations are suitable indicators for the assessment of quality of aquatic ecosystems and often comprise a variety of adaptation systems by triggering oxidants, antioxidants and hypoxia-responsive signaling proteins. Signaling pathway may lead to cell survival or cell death which is fine-tuned by both positive and negative factors, which includes hypoxia-inducible factor-1α (HIF1α), heat-shock protein-70 (HSP70), phospho-c-Jun N-terminal kinase 1/2 (p-JNK1/2) and apoptosis signal-regulating kinase-1 (ASK1). In the present study, we attempt to determine stress-mediated signaling changes and molecular mechanism behind the cell survival by comparing adipocytes of fish from field hypoxic condition and laboratory-induced hypoxic condition (in vitro hypoxia). Comparison of field and laboratory studies in fish adipocytes showed differential expression of HIF1α, HSP70, p-JNK1/2 and ASK1 with altered oxidants and antioxidants. Further, the results also suggest that in vitro hypoxic conditions mimic field hypoxic conditions. Trends of hypoxia response were same in in vitro hypoxia of control adipocytes as in Ennore estuary, and hypoxia response was more pronounced in the test adipocytes under in vitro hypoxic condition. Results of the present work suggest that hypoxia is the major crusade of water pollutants affecting fish by differential regulation of pro- and antiapoptotic proteins probably through HSP70. This may play a vital role by providing cytoprotection in pollutant-induced stressed fish adipocytes substantiated by the in vitro hypoxic studies.

Aims: Preeclampsia is a hypertensive disorder of human pregnancy and a leading cause of premature delivery and fetal growth retardation. The purpose of this study was to evaluate the expression of heat shock protein 70 (HSP70), both constitutive (HSC70) and induced (HSP70) forms, along with oxidative stress status in the placental tissues of normotensive (control group) and preeclamptic pregnancies. Materials and Methods: Placental samples were collected after delivery from normotensive pregnancies and preeclamptic patients (n = 20, each). Lipid peroxidation product malondialdehyde (MDA) and nitrite and nitrate levels, along with antioxidants such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) and glutathione were estimated in the placental homogenate to evaluate the oxidative stress. Results: Placental tissue MDA levels and concentrations of nitrite and nitrate were significantly higher in the preeclamptic group (P < 0.001) than the control group. Placental SOD and GPx activities and the reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio were significantly lowered in the preeclamptic (P < 0.001) group than the control group. Both placental HSC70 and HSP70 were in significantly higher concentrations in the preeclamptic (7.25 ± 0.76, 27.67 ± 2.32 ng/mg protein; P < 0.001) than the control (5.23 ± 0.64, 17.47 ± 1.22 ng/mg protein) group, respectively. Conclusions: The above data provide the first evidence that high levels of HSP70 are associated in the placenta of pre-eclamptic women. This enhanced expression is probably to exhibit its multiple protective effects on the cell’s response to stress.

Preeclampsia is a multisystem disorder with profound implications on both mother and fetus. Analysis of umbilical cord blood red blood cell (RBC) changes shall depict the fetal response to pregnancy-specific complications like preeclampsia. This study aims to analyze the regulation relationship between HSP90α and heme oxygenase-2 (HO-2) in cord blood RBC during preeclampsia. The lipid hydroperoxide (LHP) and 3-nitrotyrosine (3-NT) levels were measured as stress markers in cord blood RBC of both subjects. The impact of stress on RBC was assessed by measuring the level of membrane bound enzymes and assessing the changes in cord blood RBC. The expression of HSP90α and HO-2 were analyzed by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry analysis, respectively. There was significant increase in the level of LHP (p < 0.01), 3-NT (p < 0.05), HSP90α (p < 0.01) with decrease in the expression of HO-2 (p < 0.05) in cord blood RBC of preeclamptic subjects compared to normotensive subjects. Similarly, the membrane damage in preeclamptic RBC was assessed by spectrophotometrically and found to be increased by 41.7%, along with increase in number of nucleated RBC. The antiproliferative effect of carbon monoxide under stress might decrease the expression of HO-2 under conditions when there is an increasing need for RBC. The role of HSP90α level in cord blood RBC is discussed with reference to nitrative stress in preeclampsia. This study concludes the increased expression of nucleated RBC, HSP90α and corresponding decreased expression of HO-2 in such hypoxic condition may play a protective role; to prevent cord blood RBC against stress induced damage during preeclampsia.

Preeclampsia, a hypertensive pregnancy-specific disorder, has long been analyzed for its association with cellular stress. It still remains one of the most serious complications of pregnancy. It is a multi-system disorder that affects maternal vascular function and fetal growth. The physiopathology of preeclampsia is still unclear, but an imbalance between reactive oxygen species (ROS) and antioxidants, appears to be an important contributing factor. Oxidative stress has been increasingly postulated as a major contributor to endothelial dysfunction in preeclampsia (PE). The ROS promotes lipid oxidation and are known to induce stress proteins, such as hemeoxygenase 1 (HO-1) and heat-shock protein 70 (HSP70). Embryonic and placental cells are highly sensitive to oxidative stress due to their proliferate nature. Endothelial cell dysfunction is suggested to be a part of wider maternal inflammatory reaction responsible for the clinical syndrome of preeclampsia. Part of the dysfunction in endothelial cell and trophoblast is attributed to oxidative stress developed during pregnancy. The disequilibrium in compensatory antioxidant control is proposed as a causative mechanism in the pathophysiology of preeclampsia. HSP70 acts as the secondary line of defense in systems with compromised antioxidant function. This article reviews the differential expression of HSP70 and the effect of mint-tea therapy to modulate preeclamptic oxidative damage.