The Roles of Adipokines,Proinflammatory Cytokines,and Adipose Tissue Macrophages in Obesity-Associated Insulin Resistance in Modest Obesity and Early Metabolic Dysfunction

The roles of adipokines, proinflammatory cytokines, and adipose tissue macrophages in obesity-associated insulin resistance have been explored in both animal and human studies. However, our current understanding of obesity-associated insulin resistance relies on studies of artificial metabolic extremes. The purpose of this study was to explore the roles of adipokines, proinflammatory cytokines, and adipose tissue macrophages in human patients with modest obesity and early metabolic dysfunction. We obtained omental adipose tissue and fasting blood samples from 51 females undergoing gynecologic surgery. We investigated serum concentrations of proinflammatory cytokines and adipokines as well as the mRNA expression of proinflammatory and macrophage phenotype markers in visceral adipose tissue using ELISA and quantitative RT-PCR. We measured adipose tissue inflammation and macrophage infiltration using immunohistochemical analysis. Serum levels of adiponectin and leptin were significantly correlated with HOMA-IR and body mass index. The levels of expression of MCP-1 and TNF-α in visceral adipose tissue were also higher in the obese group (body mass index ≥ 25). The expression of mRNA MCP-1 in visceral adipose tissue was positively correlated with body mass index (r = 0.428, p = 0.037) but not with HOMA-IR, whereas TNF-α in visceral adipose tissue was correlated with HOMA-IR (r = 0.462, p = 0.035) but not with body mass index. There was no obvious change in macrophage phenotype or macrophage infiltration in patients with modest obesity or early metabolic dysfunction. Expression of mRNA CD163/CD68 was significantly related to mitochondrial-associated genes and serum inflammatory cytokine levels of resistin and leptin. These results suggest that changes in the production of inflammatory biomolecules precede increased immune cell infiltration and induction of a macrophage phenotype switch in visceral adipose tissue. Furthermore, serum resistin and leptin have specific roles in the regulation of adipose tissue macrophages in patients with modest obesity or early metabolic dysfunction.     

Zika Virus Infection and Stillbirths: A Case of Hydrops Fetalis,Hydranencephaly and Fetal Demise

Background

The rapid spread of Zika virus in the Americas and current outbreak of microcephaly in Brazil has raised attention to the possible deleterious effects that the virus may have on fetuses.

Methodology/Principal Findings

We report a case of a 20-year-old pregnant woman who was referred to our service after a large Zika virus outbreak in the city of Salvador, Brazil with an ultrasound examination that showed intrauterine growth retardation of the fetus at the 18^th gestational week. Ultrasound examinations in the 2^nd and 3^rd trimesters demonstrated severe microcephaly, hydranencephaly, intracranial calcifications and destructive lesions of posterior fossa, in addition to hydrothorax, ascites and subcutaneous edema. An induced labor was performed at the 32^nd gestational week due to fetal demise and delivered a female fetus. ZIKV-specific real-time polymerase chain reaction amplification products were obtained from extracts of cerebral cortex, medulla oblongata and cerebrospinal and amniotic fluid, while extracts of heart, lung, liver, vitreous body of the eye and placenta did not yield detectable products.

Conclusions/Significance

This case report provides evidence that in addition to microcephaly, there may be a link between Zika virus infection and hydrops fetalis and fetal demise. Given the recent spread of the virus, systematic investigation of spontaneous abortions and stillbirths may be warranted to evaluate the risk that ZIKV infection imparts on these outcomes.     

Murine response studies of insect cell (Sf9) expressed recombinant colorectal cancer vaccine candidate using surface plasmon resonance studies

The baculovirus vector expression system is considered a useful insect cell‐based platform for large‐scale production of recombinant biopharmaceutical glycoproteins. The GA733 antigenic protein is a 40 kDa cell surface glycoprotein that is overexpressed in human colorectal carcinoma. Three GA733‐expressing baculovirus vectors were constructed: (i) GA733 fused to the Fc fragment of human immunoglobulin G (GA733‐Fc); (ii) GA733‐Fc tagged with the endoplasmic reticulum (ER) retention signal KDEL (GA733‐FcK); and (iii) GA733‐FcK without the signal peptide [GA733‐FcK (w/o SP)]. These three recombinant proteins were expressed in Fall Armyworm (Spodoptera frugiperda) Sf9 insect cells. GA733‐Fc purified from insect culture medium (CM) and cell lysate (CL) (GA733^I‐Fc^CM and GA733^I‐Fc^CL, respectively), and GA733‐FcK and GA733‐FcK (w/o SP) purified from CL [GA733^I‐Fc^CL and GA733^I‐FcK^CL (w/o SP), respectively] were injected intraperitoneally into BALB/c mice [three times at 1 μg, with or without an adjuvant (aluminum hydroxide)]. Surface plasmon resonance (SPR) analysis (involving a chip with the immobilized GA733 antigen) showed that, in general, the serum samples from mice immunized with the adjuvant yielded stronger SPR signals than did those from mice immunized without an adjuvant. The serum samples from mice after the second injection yielded stronger signals than did those from mice before the second injection. The group immunized with GA733^I‐FcK^CL (glycosylated with an oligomannose) showed the strongest SPR signals. The SPR signals from the GA733^I‐FcK^CL group were stronger than or similar to those from mice immunized with mammalian‐cell‐expressed GA733‐Fc (GA733^M‐Fc). Thus, the baculovirus vector expression system can be used to produce immunogenic cancer glycoprotein.     

Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) and Cyclic ADP-Ribose (cADPR) Mediate Ca2+ Signaling in Cardiac Hypertrophy Induced by β-Adrenergic Stimulation

Ca²⁺ signaling plays a fundamental role in cardiac hypertrophic remodeling, but the underlying mechanisms remain poorly understood. We investigated the role of Ca²⁺-mobilizing second messengers, NAADP and cADPR, in the cardiac hypertrophy induced by β-adrenergic stimulation by isoproterenol. Isoproterenol induced an initial Ca²⁺ transients followed by sustained Ca²⁺ rises. Inhibition of the cADPR pathway with 8-Br-cADPR abolished only the sustained Ca²⁺ increase, whereas inhibition of the NAADP pathway with bafilomycin-A1 abolished both rapid and sustained phases of the isoproterenol-mediated signal, indicating that the Ca²⁺ signal is mediated by a sequential action of NAADP and cADPR. The sequential production of NAADP and cADPR was confirmed biochemically. The isoproterenol-mediated Ca²⁺ increase and cADPR production, but not NAADP production, were markedly reduced in cardiomyocytes obtained from CD38 knockout mice. CD38 knockout mice were rescued from chronic isoproterenol infusion-induced myocardial hypertrophy, interstitial fibrosis, and decrease in fractional shortening and ejection fraction. Thus, our findings indicate that β-adrenergic stimulation contributes to the development of maladaptive cardiac hypertrophy via Ca²⁺ signaling mediated by NAADP-synthesizing enzyme and CD38 that produce NAADP and cADPR, respectively.