Cold-inducible RNA-binding Protein mRNA Research Articles

Overexpression of CIRP may reduce testicular damage induced by cryptorchidism

To investigate the protective effect of overexpression of cold-inducible RNA-binding protein (CIRP) on testicular damage induced by cryptorchidism. Male BALB/c mice were made surgically cryptorchid and CIRP gene was transferred into the cryptorchid testis by in vivo electroporation. Seven or ten days after electroporation, the expression of CIRP, p53 and Fas mRNA and protein were analyzed by reverse-transcription polymerase chain reaction (RT-PCR) and immunoblotting, respectively. Meanwhile, Histopathological changes were observed by light microscope, and flow cytometry was used to detect testicular cell apoptosis. Testicular weights after transfection with pVAX1-CIRP or pVAX1 were 0.083+/-0.005 g and 0.065+/-0.004 g, respectively, on day 7(P < 0.05) and 0.078+/-0.004 g and 0.052+/-0.007 g, on day 10 (P < 0.05). Testicular cell apoptosis after transfection with pVAX1-CIRP or pVAX1 were 9.8+/-1.1 % and 20.7+/-1.3 %, respectively, on day 7 (P < 0.01) and 10.4+/-0.9 % and 27.5+/-1.2 %, on day 10 (P < 0.01). In addition, the expression of CIRP mRNA and protein in the testes transfected with pVAX1-CIRP were both increased (P < 0.05) at each indicated time point. Meanwhile, the expression of p53 was decreased on day 7 (P < 0.05) and Fas was decreased on day 10(P < 0.05). Overexpression of CIRP may reduce testicular damage induced by cryptorchidism by down-regulating the levels of p53 and Fas.

Artificial cold exposure induced stroke in renovascular hypertensive rats and its association with cold-inducible RNA binding protein mRNA expression in brain tissue and blood pressure

Background High incidence of stroke at interchange period of autumn and winter was demonstrated by epidemiological survey, and the specific causes should be further investigated. Objective To investigate the influence of artificial cold exposure on the incidence of stroke in renovascular hypertensive rats (RHR), and analyze the association with blood pressure and cold-inducible RNA binding protein (CIRP) mRNA expression in brain tissue. Design A completely randomized grouping design, a randomized control animal trial. Settings Lab of Neurology, the First Affiliated Hospital of Sun Yat-sen University; Department of Chemistry, Open laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, University of Hong Kong. Materials Male SD rats ( n = 460), weighing 80–100 g were obtained from Guangdong Province Health Animal Unit. A modified RXZ-300A intelligent artificial climate cabinet (Ningbo Jiangnan Instrument Co., Ltd., China). Methods The experiment were processed in the Lab of Neurology, the First Affiliated Hospital of Sun Yat-sen University and the Open Laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, University of Hong Kong from October 2004 to November 2005. Rats ( n = 400) were operated to establish 2-kidney 2-clip RHR model as described previously. The sham-operated rats ( n = 60) served as normotensive controls. Eight weeks later, 300 of RHR were randomly selected according to their systolic blood pressure (SBP) and divided into 3 sub-groups ( n = 100 per group): mild hypertensive group (SBP of 160–200 mm Hg), moderate hypertensive group (SBP of 200–220 mm Hg) and severe hypertensive group (SBP > 220 mm Hg). Each group was further divided into two groups ( n = 50) under ACE and non-ACE. Normal sham-operated SD rats ( n = 60), SBP < 140 mm Hg, were randomly divided into two groups: Sham-operated control group ( n = 30) under ACE and non-ACE. To establish the ACE and non-ACE treatment, rats were housed individually in artificial climate cabinet, and ACE was designed as three cycles of 12-hour light of 22 °C (7:00–19:00) and 12-hour dark of 4 °C(19:00–7:00). The non-ACE group was kept at 22 °C throughout the experiment. Main outcome measures Blood Pressure changes were measured and stroke symptom were observed; Expression of the CIRP were examined by reverse transcription-polymerase chain reaction. Results Finally 360 rats were involved in the analysis of results. ▪ Incidence of stroke: The incidence of stroke in 2k2c RHR was significantly higher after a three-day intermittent (12-hour) ACE (29.3%) as compared with that in non-ACE (17.3%) ( P < 0.05). Furthermore, the severe hypertensive 2k2c RHR (BP > 220 mm Hg) was found to have much higher incidence of stroke (66%, 33/50) than the mild (8%, 4/50) and moderate (18%) hypertensive 2k2c RHR. ▪ CIRP mRNA in brain tissue: ACE treatment stimulated the mRNA expression of CIRP in non-stroke 2k2c RHR but not in stroke 2k2c RHR ( P < 0.05). Conclusion High blood pressure and low expression of CIRP are associated with ACE induced stroke.

Oxygen-regulated expression of the RNA-binding proteins RBM3 and CIRP by a HIF-1-independent mechanism.

The transcriptional regulation of several dozen genes in response to low oxygen tension is mediated by hypoxia-inducible factor 1 (HIF-1), a heterodimeric protein composed of two subunits, HIF-1alpha and HIF-1beta. In the HIF-1alpha-deficient human leukemic cell line, Z-33, exposed to mild (8% O(2)) or severe (1% O(2)) hypoxia, we found significant upregulation of two related heterogenous nuclear ribonucleoproteins, RNA-binding motif protein 3 (RBM3) and cold inducible RNA-binding protein (CIRP), which are highly conserved cold stress proteins with RNA-binding properties. Hypoxia also induced upregulation of RBM3 and CIRP in the murine HIF-1beta-deficient cell line, Hepa-1 c4. In various HIF-1 competent cells, RBM3 and CIRP were induced by moderate hypothermia (32 degrees C) but hypothermia was ineffective in increasing HIF-1alpha or vascular endothelial growth factor (VEGF), a known HIF-1 target. In contrast, iron chelators induced VEGF but not RBM3 or CIRP. The RBM3 and CIRP mRNA increase after hypoxia was inhibited by actinomycin-D, and in vitro nuclear run-on assays demonstrated specific increases in RBM3 and CIRP mRNA after hypoxia, which suggests that regulation takes place at the level of gene transcription. Hypoxia-induced RBM3 or CIRP transcription was inhibited by the respiratory chain inhibitors NaN(3) and cyanide in a dose-dependent fashion. However, cells depleted of mitochondria were still able to upregulate RBM3 and CIRP in response to hypoxia. Thus, RBM3 and CIRP are adaptatively expressed in response to hypoxia by a mechanism that involves neither HIF-1 nor mitochondria.

Effects of ischemia and H 2O 2 on the cold stress protein CIRP expression in rat neuronal cells

Expression of CIRP (cold-inducible RNA-binding protein) is inducible at 32°C in cultured fibroblasts. Because ischemia is known to induce expression of heat shock proteins, its effect on the CIRP expression was examined using the rat transient forebrain ischemia model. The isolated rat CIRP cDNA encoded amino acids 100% identical in its sequence to mouse CIRP. Northern blot analysis revealed that the CIRP transcripts were ubiquitously expressed in various tissues. In situ hybridization histochemistry of normal rat brain revealed the expression of CIRP in neurons in the hippocampus and the cerebral cortex among others. In the hippocampus of postischemic rats, CIRP mRNA level decreased from 3–6 h after the onset of reperfusion, while it did not change in the cerebral cortex. When PC12 pheochromocytoma cells were cultured at 32°C, the CIRP mRNA level was increased. The presence of H 2O 2 in the culture media inhibited dose dependently this induction as well as constitutive expression, suggesting that the effect of brain ischemia on CIRP expression is related to generation of reactive oxygen species. Further studies are necessary to clarify the roles played by cold shock proteins in the hypothermic therapy of brain damages.

Cloning and characterization of human CIRP (cold-inducible RNA-binding protein) cDNA and chromosomal assignment of the gene.

Cold stress induces in microorganisms the synthesis of several proteins that are involved in various cellular processes such as transcription, translation and recombination. Recently, the cold-inducible RNA-binding protein (Cirp) was found to be induced in rodent cells by mild cold stress (32 degrees C). Cirp consists of an N-terminal RNA-binding domain and a C-terminal Gly-rich domain, and plays an essential role in cold-induced suppression of cell proliferation. We report here the cloning of a cDNA encoding an 18-kDa protein with 95.3% identity in an amino-acid sequence to that of mouse Cirp. The human CIRP gene has been mapped to the chromosomal locus 19p13.3 by fluorescence in-situ hybridization. CIRP mRNA is constitutively expressed in all cell lines examined, including K562, HepG2, NC65, HeLa, T24, and NEC8 cells. In all of them, the levels of CIRP mRNA and protein were increased within 12 h after a temperature down-shift from 37 degrees C to 32 degrees C. These results demonstrated that CIRP is a cold-shock protein in human cells. Identification of CIRP may provide a clue to the regulatory mechanisms of cold responses in human cells.