Cold-induced RNA-binding Protein Research Articles

Serum CIRP increases the risk of acute kidney injury after cardiac surgery.

Acute kidney injury (AKI) is a frequent perioperative complication. The underlying mechanisms of cardiac surgery-associated AKI are still not completely elucidated. Cold-induced RNA-binding protein (CIRP) has been subsequently found to be regulated by various stress conditions. During cardiac surgery and cardiopulmonary bypass (CPB), the host is subjected to hypothermia and inadequate organ perfusion, resulting in an upregulation of CIRP secretion. The aim of this study is to evaluate the role of elevated extracellular CIRP level as a contributing factor in the development of AKI. A total of 292 patients who underwent cardiac surgery were retrospectively enrolled and their serum samples were collected preoperative and postoperative. Demographic data, intraoperative data, in-hospital outcomes, and the occurrence of AKI were also collected for the patients. The correlation between CIRP and intraoperative procedures, as well as its association with postoperative outcomes were analyzed. In multivariable analysis, higher ΔCIRP (p = 0.036) and body mass index (p = 0.015) were independent risk factors for postoperative AKI. Meanwhile, patients with postoperative AKI exhibited lower survival rate in 2-year follow-up (p = 0.008). Compared to off-pump coronary artery bypass grafting surgery, patients who underwent on-pump coronary artery bypass grafting, valve surgery, aortic dissection and other surgery showed higher ΔCIRP, measuring 1,093, 666, 914 and 258 pg/mL, respectively (p < 0.001). The levels of ΔCIRP were significantly higher in patients who underwent CPB compared to those who did not (793.0 ± 648.7 vs. 149.5 ± 289.1 pg/mL, p < 0.001). Correlation analysis revealed a positive correlation between ΔCIRP levels and the duration of CPB (r = 0.502, p < 0.001). Patients with higher CIRP levels are at greater risk of postoperative AKI (OR: 1.67, p = 0.032), especially the stage 2-3 AKI (OR: 2.11, p = 0.037). CIRP secretion increases with prolonged CPB time after cardiac surgery, and CIRP secretion is positively correlated with the duration of CPB. Cardiac surgeries with CPB exhibited significantly higher levels of CIRP compared to non-CPB surgeries. Elevation of CIRP level is an independent risk factor for the incidence of AKI, especially the severe AKI, and were associated with adverse in-hospital outcomes.

CIRBP Increases the synthesis and secretion of steroid hormones by in yak granulaso cells

As a regulatory protein that upregulates transcription in response to various stresses, cold-induced RNA-binding protein (CIRBP) is involved in a variety of physiological pathological processes in cells. However, little is known about the role of CIRBP in regulating autophagy and the synthesis and secretion of ovarian steroid hormones (estradiol E2 and progesterone P4). This study aimed to explore whether the synthetic secretion of ovarian steroid hormones is related to CIRBP-regulated autophagy. We detected the differential expression of CIRBP, LC3, E2 and P4 in YGCs cultured at mild low temperature (32 °C) for 6 and 12 h. CIRBP, LC3, E2 and P4 expression was increased in response to low temperature in YGCs. In order to illustrate that the changes in secretion of E2/P4 and autophagy might be caused by CIRBP induced by low temperature, we overexpressed CIRBP in YGCs cultured in vitro to detect its effects on autophagy and steroid hormone synthesis and secretion. We found that overexpression of CIRBP can induce autophagy of YGCs and enhance the synthesis and secretion of E2 and P4, suggesting that mild hypothermia may activate autophagy by inducing the expression of CIRBP and enhance the synthesis and secretion of E2 and P4. To further explore the relationship between CIRBP regulated autophagy and steroid hormone synthesis and secretion, we verified it by regulating autophagy. The results showed that Inhibition of autophagy significantly reversed CIRBP overexpression-enhanced autophagy and synthetic secretion of E2, P4 in YGCs, while activated autophagy showed similar results to overexpression of CIRBP. In conclusion, our data suggest that autophagy is involved in the synthesis and secretion of YGCs E2 and P4 and is associated with overexpression of CIRBP.

FGF21 modulates hippocampal cold-shock proteins and CA2-subregion proteins in neonatal mice with hypoxia-ischemia.

Fibroblast growth factor 21 (FGF21) is a neuroprotectant with cognitive enhancing effects but with poorly characterized mechanism(s) of action, particularly in females. Prior studies suggest that FGF21 may regulate cold-shock proteins (CSPs) and CA2-marker proteins in the hippocampus but empirical evidence is lacking. We assessed in normothermic postnatal day (PND) 10 female mice, if hypoxic-ischemic (HI) brain injury (25 min 8% O2/92% N2) altered endogenous levels of FGF21 in serum or in the hippocampus, or its receptor β-klotho. We also tested if systemic administration of FGF21 (1.5 mg/kg) modulated hippocampal CSPs or CA2 proteins. Finally, we measured if FGF21 therapy altered markers of acute hippocampal injury. HI increased endogenous serum FGF21 (24 h), hippocampal tissue FGF21 (4d), and decreased hippocampal β-klotho levels (4d). Exogenous FGF21 therapy modulated hippocampal CSP levels, and dynamically altered hippocampal CA2 marker expression (24 h and 4d). Finally, FGF21 ameliorated neuronal damage markers at 24 h but did not affect GFAP (astrogliosis) or Iba1 (microgliosis) levels at 4d. FGF21 therapy modulates CSP and CA2 protein levels in the injured hippocampus. These proteins serve different biological functions, but our findings suggest that FGF21 administration modulates them in a homeostatic manner after HI. Hypoxic-ischemic (HI) injury in female post-natal day (PND) 10 mice decreases hippocampal RNA binding motif 3 (RBM3) levels in the normothermic newborn brain. HI injury in normothermic newborn female mice alters serum and hippocampal fibroblast growth factor 21 (FGF21) levels 24 h post-injury. HI injury in normothermic newborn female mice alters hippocampal levels of N-terminal EF-hand calcium binding protein 2 (NECAB2) in a time-dependent manner. Exogenous FGF21 therapy ameliorates the HI-mediated loss of hippocampal cold-induced RNA-binding protein (CIRBP). Exogenous FGF21 therapy modulates hippocampal levels of CA2-marker proteins after HI.

Interpretation of the Genotype by Tissue Interactions of Four Genes (AFP1, CIRP, YB-1, and HMGB1) in Takifugu rubripes Under Different Low-Temperature Conditions.

Background: The differential expression of the same gene in different tissues could be due to the genotype effect, tissue effect, and/or genotype × tissue interactions. However, the genetic mechanisms responsible for this differential expression have not been reported to date. Methods: Four resistance genes to low temperature, the genes for antifreeze protein (AFP), cold induced RNA binding protein (CIRP), high mobility group protein box-1 (HMGB1), and Y-box binding protein (YB-1), were measured by PCR in the liver, spleen, kidney, brain, heart, intestine, muscle, gonad, and skin of Takifugu rubripes cultured under different temperature conditions (18, 13, 8, and 5°C). Split-split-plot analysis of variance, additive main effects and multiplicative interaction (AMMI) and genotype main effects and genotype × environment interaction (GGE) biplot analysis were used to evaluate the effects of genotype × tissue interactions on gene expression. Results: The results of split-split-plot analysis of variance showed that water temperature has a significant effect on the expression of T. rubripes cold resistant genes, while tissue × gene interaction has a highly significant effect on it. AMMI analysis showed that the contributions of genotype, tissue, and genotype × tissue interactions to the total variation in gene expression followed two trends: 1) as temperature decreased, the gene effect increased gradually and the genotype × tissue interaction decreased gradually; 2) the gene effect at 18 and 13°C was significantly lower than that at 8 and 5°C, while the interaction at 18 and 13°C was significantly higher than that at 8 and 5°C. GGE analysis showed that: at all temperatures except 8°C, the expression rankings of all four genes were highly positively correlated in all tissues except muscle; the expression stability of the genes was the same at 18°C/13°C and at 8°C/5°C; and AFP1 showed the best expression and stability among the four genes. Conclusion: 8°C/5°C as the suitable temperature for such experiments for T. rubripes. Among the four antifreeze genes evaluated in this study, AFP1 had the best expression and stability.

Cold-Induced RNA-Binding Protein Promotes Glucose Metabolism and Reduces Apoptosis by Increasing AKT Phosphorylation in Mouse Skeletal Muscle Under Acute Cold Exposure.

The main danger of cold stress to animals in cold regions is systemic metabolic changes and protein synthesis inhibition. Cold-induced RNA-binding protein is a cold shock protein that is rapidly up-regulated under cold stimulation in contrast to the inhibition of most proteins and participates in multiple cellular physiological activities by regulating targets. Therefore, this study was carried out to investigate the possible mechanism of CIRP-mediated glucose metabolism regulation and survival promotion in skeletal muscle after acute cold exposure. Skeletal muscle and serum from mice were obtained after 0, 2, 4 and 8 h of acute hypothermia exposure. Subsequently, the changes of CIRP, metabolism and apoptosis were examined. Acute cold exposure increased energy consumption, enhanced glycolysis, increased apoptosis, and up-regulated CIRP and phosphorylation of AKT. In addition, CIRP overexpression in C2C12 mouse myoblasts at each time point under 37°C and 32°C mild hypothermia increased AKT phosphorylation, enhanced glucose metabolism, and reduced apoptosis. CIRP knockdown by siRNA interference significantly reduced the AKT phosphorylation of C2C12 cells. Wortmannin inhibited the AKT phosphorylation of skeletal muscle after acute cold exposure, thereby inhibiting glucose metabolism and aggravating apoptosis. Taken together, acute cold exposure up-regulates CIRP in mouse skeletal muscle, which regulates glucose metabolism and maintains energy balance in skeletal muscle cells through the AKT signaling pathway, thus slowing down the apoptosis of skeletal muscle cells.

Transcriptome analysis reveals molecular mechanisms responsive to acute cold stress in the tropical stenothermal fish tiger barb (Puntius tetrazona)

BackgroundTropical stenothermal fish exhibit special tolerance and response to cold stress. However current knowledge of the molecular mechanisms response to cold stress in aquatic ectotherms is largely drawn from eurythermal or extreme stenothermal species. The tiger barb Puntius tetrazona is a tropical stenothermal fish, with great popularity in aquarium trade and research.ResultsTo investigate the response mechanism of P. tetrazona to low temperature, fish were exposed to increasing levels of acute cold stress. Histopathological analysis showed that the brain, gill, liver and muscle tissues appeared serious damage after cold stress (13 °C). Brain, gill, liver and muscle tissues from control (CTRL) groups (27 °C) and COLD stress groups (13 °C) of eight-month fish (gender-neutral) were sampled and assessed for transcriptomic profiling by high-throughput sequencing. 83.0 Gb of raw data were generated, filtered and assembled for de novo transcriptome assembly. According to the transcriptome reference, we obtained 392,878 transcripts and 238,878 unigenes, of which 89.29% of the latter were annotated. There were 23,743 differently expressed genes (DEGs) been filtered from four pairs of tissues (brain, gill, liver and muscle) between these cold stress and control groups. These DEGs were mainly involved in circadian entrainment, circadian rhythm, biosynthesis of steroid and fatty acid. There were 64 shared DEGs between the four pairs of groups, and five were related to ubiquitylation/deubiquitylation. Our results suggested that ubiquitin-mediated protein degradation might be necessary for tropical stenothermal fish coping with acute cold stress. Also, the significant cold-induced expression of heat shock 70 kDa protein (HSP70) and cold-induced RNA-binding protein (CIRBP) was verified. These results suggested that the expression of the molecular chaperones HSP70 and CIRBP in P. tetrazona might play a critical role in coping with acute cold stress.ConclusionsThis is the first transcriptome analysis of P. tetrazona using RNA-Seq technology. Novel findings about tropical stenothermal fish under cold stress (such as HSP70 and CIRBP genes) are presented here. This study contributes new insights into the molecular mechanisms of tropical stenothermal species response to acute cold stress.

In This Issue

HomeCirculation ResearchVol. 126, No. 12In This Issue Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIn This Issue Ruth Williams Ruth WilliamsRuth Williams Search for more papers by this author Originally published4 Jun 2020https://doi.org/10.1161/RES.0000000000000397Circulation Research. 2020;126:1667is related toAssociation of Inpatient Use of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers With Mortality Among Patients With Hypertension Hospitalized With COVID-19ACEI/ARB on COVID-19 in Patients With Hypertension (p 1671)Hypertensive patients taking ACE inhibitors or angiotensin II blockers should continue such treatments if infected with coronavirus, say Zhang et al.Download figureDownload PowerPointPatients with hypertension have an increased risk of death from COVID-19. While the high blood pressure itself is likely to blame, concerns have been raised that medications used to treat hypertension—specifically ACE inhibitors (ACEI) and angiotensin II receptor blockers (ARB)—may worsen coronavirus infection. Research in animals showed these drugs increased expression of ACE2—the protein on lung cells used by the virus to gain entry. Conflicting evidence showed these drugs might reduce lung injury in pneumonia patients, however. To weigh up the benefits and risks of ACEI/ARB use, Zhang and colleagues performed a retrospective analysis of 1128 patients with COVID-19 and hypertension who were treated at nine hospitals in Hubei province, China. Of the patients, 188 took ACEI/ARB during their hospital stay and 940 did not. The ages, sexes, and comorbidities in the two groups were similar. After 28 days of follow up, 99 of the patients had died—7 from the group taking ACEI/ARB (3.7%) and 92 from the group that did not (9.8%). The team concludes that treatment of hypertension patients with ACEI/ARB does not increase risk of COVID-19 mortality and may even reduce the threat.ERR Signaling and Cardiac Maturation (p 1685)ERR is a maturation switch controlling heart cell development, say Sakamoto et al.Download figureDownload PowerPointFrom fetal to postnatal development, the human heart goes through significant changes including an expansion of mitochondrial numbers, a change in fuel utilization, replacement of fetal contractile proteins with adult ones, and increases in ion uptake and release. The transcription factor ERR was known to drive postnatal mitochondria biogenesis. Now Sakamoto and colleagues show it drives these other developmental changes, too. They developed a genetic method to knockdown expression of ERR in early postnatal mice and, when the animals were 5 weeks old, analyzed their transcriptomes. In the mice lacking ERR, there was a reduction in expression of genes involved in ion channeling and handling, fatty acid oxidation (the major metabolic process of the adult heart) as well as adult versions of contractile proteins compared with that seen in control animals. By contrast, expression of genes encoding fetal contractile proteins and factors involved in glycolysis—the metabolic pathway characteristic of fetal hearts—was upregulated. In heart failure, cardiomyocytes can revert to fetal-like cells. The authors, therefore, suggest that boosting ERR might be a way to counteract such pathology as well as a way to induce and study cardiomyocyte maturation in cultured progenitor cells.CIRP Governs the Heart Rate Response to Stress (p 1706)Xie et al discover a factor that keeps heart rate under control during stress.Download figureDownload PowerPointDuring the acute stress response (also known as fight-or-flight), heart rate increases rapidly due to the effect of adrenergic signaling on the cells of the sinoatrial node (SAN)—the heart’s pacemaker. Within SAN cells, levels of the signaling factor cAMP ramp up, which in turn increases the cells’ calcium handling and firing rates. But, a racing heartbeat can be damaging if excessive or prolonged, so what keeps the system in check? Xie and colleagues now show that cold-induced RNA-binding protein (CIRP) puts the brakes on by limiting cAMP levels. In rats that lack CIRP, the team showed, adrenergic signaling (treatment with isoproterenol) caused hearts to beat faster for longer than it did in wild-type animals, while basal rates were comparable. Cardiac tissue from the CIRP-lacking animals showed higher-than-usual levels of cAMP after isoproterenol treatment, and this was due to lower-than-usual levels of phosphodiesterase (PDE), the enzyme that normally degrades cAMP. The team went on to show that CIRP normally binds and stabilizes PDE messenger RNA ensuring a ready supply of the enzyme to restrain cAMP signaling. As well as revealing this crucial control mechanism, the work highlights CIRP as a potential new target for future heart-rate–lowering medications, the authors say. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesAssociation of Inpatient Use of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers With Mortality Among Patients With Hypertension Hospitalized With COVID-19Peng Zhang, et al. Circulation Research. 2020;126:1671-1681 June 5, 2020Vol 126, Issue 12 Advertisement Article InformationMetrics © 2020 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000397 Originally publishedJune 4, 2020 PDF download Advertisement

Cold-induced RNA-binding protein (CIRBP) regulates the expression of Src-associated during mitosis of 68 kDa (Sam68) and extracellular signal-regulated kinases (ERK) during heat stress-induced testicular injury

In this study, the ability of cold-induced RNA-binding protein (CIRBP) to regulate the expression of Src-associated during mitosis of 68 kDa (Sam68) and extracellular signal-regulated kinases (ERK) in the mouse testis and mouse primary spermatocytes (GC-2spd cell line) before and after heat stress was examined to explore the molecular mechanism by which CIRBP decreases testicular injury. A mouse testicular hyperthermia model, a mouse primary spermatocyte hyperthermia model and a low CIRBP gene-expression cell model were constructed and their relevant parameters were analysed. The mRNA and protein levels of CIRBP and Sam68 were significantly decreased in the 3-h and 12-h testicular heat-stress groups, extracellular signal-regulated kinase 1/2 (ERK1/2) protein expression was not significantly affected but phospho-ERK1/2 protein levels were significantly decreased. GC-2spd cellular heat-stress results showed that the mRNA and protein concentrations of CIRBP and Sam68 were reduced 48h after heat stress. In the low CIRBP gene-expression cell model, CIRBP protein expression was significantly decreased. Sam68 mRNA expression was significantly decreased only at the maximum transfection concentration of 50nM and Sam68 protein expression was not significantly affected. These findings suggest that CIRBP may regulate the expression of Sam68 at the transcriptional level and the expression of phospho-ERK1/2 protein, both of which protect against heat-stress-induced testicular injury in mice.

Infants Uniquely Express High Levels of RBM3 and Other Cold-Adaptive Neuroprotectant Proteins in the Human Brain

Neuroprotective cold-shock proteins (CSPs) are abundant in the normothermic neonatal rodent brain but decrease with advancing neurodevelopmental age and are low or absent in the adult brain. It has not been established if neurodevelopmental age alters the baseline expression of CSPs in the human brain. Here, we tested the hypothesis that protein levels of RNA-binding motif 3 (RBM3), reticulon-3 (RTN3), and cold-induced RNA-binding protein (CIRBP) are abundant in the normothermic developing human brain but low-to-absent in adults. We also tested if β-klotho (KLB) is expressed in the developing brain; KLB functions as a coreceptor that controls tissue-specific binding and activity of the systemically circulating thermogenic hormone fibroblast growth factor 21 (FGF21), and is predominantly expressed in the liver, pancreas, and in adipose cells. Methods: Hippocampi and anterior prefrontal cortices (aPFCs/BA10) from a total of 20 male and 20 female subjects were obtained from the NIH NeuroBioBank. CSP and KLB levels were measured in: infants < 1 year old (n = 8), toddlers aged 1–2 years (n = 8), children aged 3–5 years (n = 7), 18-year-old adolescents (n = 8), and adults aged 31–34 years (n = 8). An equal number of male and female (n = 4 each) samples were pooled into each age group, except in the 3- to 5-year-olds which comprised 3 male and 4 female specimens due to sample availability. In total, 78 whole-brain tissues were dissociated using a bead-based Precellys homogenizer to generate equivalent homogenates, and levels of protein targets subsequently analyzed by Western blotting. Results: Infants had the highest levels of RBM3 and other CSPs in the brain compared to all other ages. In the hippocampus, CSPs were detected predominantly in infants. In the aPFC, CSP levels were highest in infants, moderate-to-low in toddlers/children, and below assay detection limits in adolescents/adults. Germane to the thermogenic FGF21/KLB signaling axis, our results confirm that KLB is absent in the adult hippocampus/aPFC as reported by others. In contrast, we report for the first time that KLB is abundant in the early developing human brain; KLB levels were highest in the infant hippocampus/aPFC and moderately expressed in toddlers. RBM3 is a potent neuroprotective CSP. Thus, the impact of these findings on the observed efficacy of therapeutic hypothermia in neonatal brain injury merits further investigation.

An Immunohistochemical Approach to Identify the Sex of Young Marine Turtles.

Marine turtles exhibit temperature-dependent sex determination (TSD). During critical periods of embryonic development, the nest's thermal environment directs whether an embryo will develop as a male or female. At warmer sand temperatures, nests tend to produce female-biased sex ratios. The rapid increase of global temperature highlights the need for a clear assessment of its effects on sea turtle sex ratios. However, estimating hatchling sex ratios at rookeries remains imprecise due to the lack of sexual dimorphism in young marine turtles. We rely mainly upon laparoscopic procedures to verify hatchling sex; however, in some species, morphological sex can be ambiguous even at the histological level. Recent studies using immunohistochemical (IHC) techniques identified that embryonic snapping turtle (Chelydra serpentina) ovaries overexpressed a particular cold-induced RNA-binding protein in comparison to testes. This feature allows the identification of females vs. males. We modified this technique to successfully identify the sexes of loggerhead sea turtle (Caretta caretta) hatchlings, and independently confirmed the results by standard histological and laparoscopic methods that reliably identify sex in this species. We next tested the CIRBP IHC method on gonad samples from leatherback turtles (Dermochelys coriacea). Leatherbacks display delayed gonad differentiation, when compared to other sea turtles, making hatchling gonads difficult to sex using standard H&E stain histology. The IHC approach was successful in both C. caretta and D. coriacea samples, offering a much-needed tool to establish baseline hatchling sex ratios, particularly for assessing impacts of climate change effects on leatherback turtle hatchlings and sea turtle demographics. Anat Rec, 300:1512-1518, 2017. © 2017 Wiley Periodicals, Inc.

RNA binding motif protein 3: a potential biomarker in cancer and therapeutic target in neuroprotection.

RNA binding motif 3 (RBM3) is a highly conserved cold-induced RNA binding protein that is transcriptionally up-regulated in response to harsh stresses. Featured as RNA binding protein, RBM3 is involved in mRNA biogenesis as well as stimulating protein synthesis, promoting proliferation and exerting anti-apoptotic functions. Nowadays, accumulating immunohistochemically studies have suggested RBM3 function as a proto-oncogene that is associated with tumor progression and metastasis in various cancers. Moreover, emerging evidences have also indicated that RBM3 is equally effective in neuroprotection. In the present review, we provide an overview of current knowledge concerning the role of RBM3 in various cancers and neuroprotection. Additionally, its potential roles as a promising diagnostic marker for cancer and a possible therapeutic target for neuro-related diseases are discussed.

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HomeCirculation ResearchVol. 116, No. 10In This Issue Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBIn This Issue Ruth Williams Ruth WilliamsRuth Williams Search for more papers by this author Originally published8 May 2015https://doi.org/10.1161/RES.0000000000000056Circulation Research. 2015;116:1629Nonvenous Origin of Lymphatic Vessels (p 1649)Download figureDownload PowerPointMartinez-Corral et al discover that the mammalian lymphatic system doesn’t solely develop from blood vessels as previously thought.It is currently believed that during embryogenesis, lymph vessels arise from veins by the transdifferentiation of venous endothelial cells into lymphatic endothelial cells (LECs). However, research in chickens and frogs suggests LECs could also be derived from a secondary source. Martinez-Corral and colleagues have now found evidence of a nonvenous source of LECs in mammals as well. They showed that in the lumbar region of embryonic mice, dermal lymph vessels arise independently from subcutaneous vessels, suggesting the two might have different origins. To confirm this suspicion, they performed lineage tracing experiments, in which they genetically labeled venous endothelial cells—identified by expression of the protein Tie2—such that the cells and all their progeny would fluoresce green. They found, however, that many LECs were not fluorescent, indicating that they had not arisen solely from these venous endothelial cells. The team also showed that deleting a critical LEC driver—Prox1—specifically from the Tie2 lineage, did not eliminate all LECs, providing further evidence of an alternative orgin. These findings increase our understanding of the origins of lymphatic vessels, which could potentially aid the development of new therapeutic lymphatic regeneration approaches in the future.CIRP Regulates Cardiac Repolarization (p 1655)Download figureDownload PowerPointLi et al find that cold-induced RNA binding protein regulates repolarization of the heart.The Cold-Induced RNA binding Protein (CIRP) is rapidly upregulated in response to stresses such as low temperature, hypoxia, and UV exposure, but the protein has also been implicated in a number of physiological processes such as circadian regulation of gene expression and proinflammatory responses. Li and colleagues have now investigated the function of CIRP in the heart. The team engineered rats in which the gene encoding CIRP was homozygously deleted and found that the animals’ hearts exhibited a distinctly reduced QT interval—the time it takes for electrical depolarization and repolarization during a single heartbeat. The team went on to show that this unusual electrical activity in the knockout mice was associated with an increase in the expression of the subunits of the potassium channel that contribute to the repolarization of the heart. They also showed that in normal cells CIRP bound to the mRNAs of these channel subunits—most likely suppressing their expression. The finding that CIRP regulates repolarization of the heart provides new understanding of the electrophysiological mechanisms at work both during normal functioning of the heart as well as under pathological conditions such as arrhythmia.Iron Deficiency and Pulmonary Hypertension (p 1680)Download figureDownload PowerPointIron deficiency promotes the development of pulmonary hypertension in rats, report Cotroneo et al.Patients with pulmonary hypertension commonly exhibit low iron levels in the blood, and such iron deficiency is associated with poorer disease prognoses. However, whether iron deficiency contributes to or is merely a consequence of pulmonary hypertension is a matter of debate. Controneo and colleagues now present evidence suggesting that iron deficiency alone can promote pulmonary hypertension, at least in rats. To examine the role of iron-deficiency, Controneo and colleagues restricted the dietary iron intake in otherwise healthy rats and found that over the course of four weeks the animals developed multiple symptoms of pulmonary hypertension including increased pulmonary blood pressure, right ventricular hypertrophy, enlargement of the heart, infiltration of inflammatory cells, and a profound remodeling of the pulmonary vasculature—with blood vessels displaying smaller lumens and hypertrophy of the walls. They also noted altered metabolic activity in pulmonary vessels—such as increased glucose uptake and reduced mitochondrial activity—suggesting a switch from aerobic to anaerobic respiration. When the rats were given a dose of intravenous iron, however, these symptoms were reversed. Based on these observations, the authors suggest that ongoing clinical evaluations of iron supplementation in pulmonary hypertension patients could yield promising results. Previous Back to top Next FiguresReferencesRelatedDetails May 8, 2015Vol 116, Issue 10 Advertisement Article InformationMetrics © 2015 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000056 Originally publishedMay 8, 2015 PDF download Advertisement

A Novel Approach to Identify the Sex of Marine Turtles

Marine turtles exhibit temperature dependent sex determination (TSD). During critical periods of embryonic development, the nest's thermal environment directs whether an embryo will develop as a male or a female. Nests that incubate at warmer sand temperatures tend to produce female-biased sex ratios. The rapid increase of global temperature highlights the need for a clear assessment of effects on sea turtle sex ratios. However, identifying hatchling sex ratios at rookeries remain as coarse estimates because the mechanisms that trigger male vs. female development are understood only in part. We currently rely mainly upon laparoscopic procedures to verify hatchling sex; however, in some species, morphological sex can be ambiguous even at the histological level. Recent studies using immunohistochemical techniques identified that red-eared slider (Trachemys scripta) embryos over-expressed a cold-induced RNA binding protein in the ovary when compared to developing testes. We developed a variation of this technique and successfully identified the sexes of loggerhead sea turtle (Caretta caretta) hatchlings, a species that can also be identified reliably using standard histological and laparoscopic methods. We then tested the technique with a more challenging species, the leatherback turtle (Dermochelys coriacea), species that retains many neotenic features. The morphology of leatherback hatchling gonads remains difficult to interpret, particularly when dead-in-nest hatchlings and embryos are the source tissues. Our purpose is to introduce the modified procedure and its efficacy. This new technique has the potential to greatly enhance our ability to verify hatchling sex ratios and identify baseline sex ratios; both fundamental steps in assessing global climate change on sea turtle populations.

Circadian Rhythms: Per2bations in the Liver Clock

A master circadian clock resides in the brain and is required to synchronize the clocks in peripheral tissues such as the liver. Until now, it has been unclear how the central clock synchronizes the peripheral ones. New work points to one of the core clock genes, mPer2, as an essential link in this chain.

AtGRP2, a cold-induced nucleo-cytoplasmic RNA-binding protein, has a role in flower and seed development

The glycine-rich protein AtGRP2 is one of the four members of the cold-shock domain (CSD) protein family in Arabidopsis. It is characterized by the presence of a nucleic acid-binding CSD domain, two glycine-rich domains and two CCHC zinc-fingers present in nucleic acid-binding proteins. In an attempt to further understand the role of CSD/GRP proteins in plants, we have proceeded to the functional characterization of the AtGRP2 gene. Here, we demonstrate that AtGRP2 is a nucleo-cytoplasmic protein involved in Arabidopsis development with a possible function in cold-response. Expression analysis revealed that the AtGRP2 gene is active in meristematic tissues, being modulated during flower development. Down-regulation of AtGRP2 gene, using gene-silencing techniques resulted in early flowering, altered stamen number and affected seed development. A possible role of AtGRP2 as an RNA chaperone is discussed.

Effect of moderate hypothermia on gene expression by THP-1 cells: a DNA microarray study

The mechanisms by which moderate hypothermia (32 degrees C for 12-72 h) affect human cellular function are unclear. We tested the hypothesis that it produces broad changes in mRNA expression in vitro. Acute monocytic leukemia (THP-1) cells were incubated under control conditions (37 degrees C) or moderate hypothermia (32 degrees C) for 24 h. RNA was extracted, and the hypothermic response was confirmed by examining the expression of the cold-induced RNA-binding protein (CIRBP) gene by RT-PCR. Gene expression analysis was performed on seven sets of paired samples with Affymetrix U133A chips using established statistical methods. Sequences were considered affected by cold if they showed statistically significant changes in expression and also met published post hoc filter criteria (changes in geometric mean expression of > or =2-fold and expression calls of "present" or "marginal" in at least half of the experiments). Changes in the expression of selected sequences were further confirmed by PCR. Sixty-seven sequences met the criteria for increased expression (including cold-inducible genes CIRBP and RNA binding motif 3), and 100 sequences showed decreased expression as a result of hypothermia. Functional categories affected by hypothermia included genes involved in immune responses; cell growth, proliferation, and differentiation; and metabolism and biosynthesis. Several heat shock proteins (HSPs) showed decreases in expression. Moderate hypothermia produces substantial changes in gene expression, in categories potentially of systemic importance. Cold exposure without rewarming decreased the expression of several HSPs. These in vitro findings suggest that prolonged hypothermia in vivo might be capable of producing physiologically relevant changes in gene expression by circulating leukocytes.