Abstract P4-04-10: Molecular features of dormancy in ER+ breast cancers

Background:Late recurrence (emergence from dormancy) is characteristic of ER+ breast cancers. Despite adjuvant endocrine therapy, many breast cancers recur decades after their initial diagnosis and treatment. Why this occurs is poorly understood.

Methods: We studied 2 independent datasets of endocrine treated, ER+ breast cancers with up to 20 years follow-up. The 1st comprised matched samples from the primary tumor pretreatment at diagnosis and the first recurrence after or during adjuvant endocrine therapy (all FFPE). The 2nd dataset comprised pretreatment biopsies only (all snap frozen). For both datasets, high quality RNA was amplified, labelled, and subjected to transcriptome analysis using the Affymetrix technology (U133 Plus 2.0). Low quality data were identified using 'simpleaffy' and 'ffpe', and removed; all tools were from the R package unless otherwise noted. Remaining data were normalized using 'frma'. Genes differentially expressed between early (≤3 years) and late (≥ 5 years) were selected using limma. Unsupervised hierarchical clustering and PCA explored the structure of the data.

A similar molecular analysis was done on the 2nd dataset. A classification scheme that robustly separated early from late recurrences was validated in an independent public dataset of comparable patients, array platform, and frozen tissues. We also explored features in pretreatment samples that predetermined response duration.

Results: Genes that separated pretreatment specimens by recurrence time did not separate posttreatment specimens. Specimens did not cluster in patient pairs or by site of recurrence.

8245 genes were differentially expressed between early and late recurrences in the FFPE samples, while 2400 genes were significantly different in the same comparison in the frozen samples. Initial pathway analysis was done on each dataset independently using IPA (Ingenuity® Systems, www.ingenuity.com). 70 canonical pathways were identified in common between the two datasets (pretreatment). We then looked for genes regulated in both datasets (ignores FFPE and frozen tissue as source). There were 279 genes in common that differentially regulated in the same direction (upregulated; downregulated). IPA analysis of these genes identified 49 canonical pathways. We also explored the differentially expressed gene sets using 'GSEA' (www.software.broadinstitute.org/gsea/index.jsp). Pathways consistently associated with early vs. late recurrence include integrin signaling, the unfolded protein response, endoplasmic reticulum stress, actin-based motility, and estrogen biosynthesis.

Conclusion: Analysis of pretreatment tumors can predict early recurrences from those that will remain dormant and recur much later. Recurrent tumors exhibit a remodeled molecular landscape that likely reflects the effects of treatments and/or a recreation of a niche with potentially common features at the site of recurrence. Changes in molecular signaling associated with duration of recurrence are consistent with our experimental model studies in vitro implicating UPR signaling as a major integrator of response to endocrine therapy and duration of survival. Additional data sets are being arrayed and more detailed molecular signaling studies are in progress.

Citation Format: Clarke R, Dixon MJ, Jin L, Turnbull A, Hu R, Zwart A, Wang Y, Xuan J, Sengupta S, Renshaw L, Sims A, Liu MC. Molecular features of dormancy in ER+ breast cancers [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-04-10.

Therapeutic drug monitoring of isoniazid and rifampicin during anti-tuberculosis treatment in Auckland, New Zealand

SETTING

There is uncertainty as to the optimal therapeutic concentrations of anti-tuberculosis drugs to achieve cure.

OBJECTIVE

To characterise the use of therapeutic drug monitoring (TDM), and identify risk factors and outcomes for those with concentrations below the drug interval.

DESIGN

Patients treated for tuberculosis (TB) who had rifampicin (RMP) or isoniazid (INH) concentrations measured between 1 January 2005 and 31 December 2012 were studied retrospectively. Matched concentrations and drug dosing time were assessed according to contemporary regional drug intervals (RMP > 6 μmol/l, INH > 7.5 μmol/l) and current international recommendations (RMP > 10 μmol/l, INH > 22 μmol/l). Outcomes were assessed using World Health Organization criteria.

RESULTS

Of 865 patients, 121 had concentrations of either or both medications. RMP concentrations were within the regional drug intervals in 106/114 (93%) and INH in 91/100 (91%). Concentrations were within international drug intervals for RMP in 76/114 (67%) and INH in 53/100 (53%). Low weight-based dose was the only statistically significant risk factor for concentrations below the drug interval. Of the 35 patients with low concentrations, 21 were cured, 9 completed treatment and 5 transferred out. There were no relapses during follow-up (mean 66.5 months).

CONCLUSION

There were no clinically useful characteristics to guide use of TDM. Many patients had concentrations below international therapeutic intervals, but were successfully treated.

RAPID COMMUNICATION: Generation of FGF5 knockout sheep via the CRISPR/Cas9 system

Sheep are an important source of fiber production. Fibroblast growth factor 5 (FGF5) is a dominant inhibitor of length of the anagen phase of the hair cycle. Knockout or silencing of the gene results in a wooly coat in mice, donkeys, dogs, and rabbits. In sheep breeding, wool length is one of the most important wool quality traits. However, traditional breeding cannot accurately and efficiently mediate an advanced genotype into the sheep genome. In this study, we generated 3 knockout sheep via the 1-step clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system. Sequencing analysis confirmed that mutations in the gene existed in all germ lines of 3 founders: besides the intact sequence, 3 kinds of deletions in the gene (including 5, 13, and 33 bp) were detected. The changes in the primary and senior structure of the FGF5 protein due to the 3 deletions in founders suggested that the FGF5 protein was dysfunctional. In addition, the expression level of intact mRNA in heterozygous individuals decreased compared with the wild types ( < 0.01). Functionally, we discovered that wool length in founders was significantly longer than in wild types ( < 0.05). Collectively, the knockout sheep with the longer wool length phenotype will provide an efficient way for fast genetic improvement of sheep breeding and promote the development of wool industry.

Structural and magneto-electronic properties of transition metal doped phosphorus nanotubes

Transition metal doped phosphorus nanotubes can show particular magnetic properties and act as electric field-controllable magnetic/nonmagnetic switch devices.

[Application of Metagenomics in Forensic Identification]

With the development of molecular biology and genomics, metagenomics is playing a more important role in forensic science and forensic identification. In recent years, as a branch discipline studying the composition profile and diversity of microbe flora as well as studying the interaction within microbe and with environment, the application of metagenomics has gradually risen and brought new opportunities for forensic identification-related area. In this review, strategy of metagenomics and its application in forensic identification including individual identification, origin determination of biological stain in crime scene and drug abuse detection are summarized. This article aims to elucidate the role and application value of metagenomics in forensic science.

[The efficacy of thyroid hormone replacement therapy in patients with hypothyroidism and OSAHS: a Meta analysis]

Objective:To systematically evaluate the impact of thyroid hormone replacement in patients with OSAHS and hypothyroidism.Method:The related case-control study of thyroid hormone replacement in patients with OSAHS and hypothyroidism had been searched from Cochrane Library, PubMed, CNKI, Chinese Biomedical Literature Database, Wanfang Resource Database.The case-control study which were in line with the condition need to be evaluated the quality and to be extracted in literature. The RevMan 5.3 and STATA softwares were applied to carry out the Meta analysis.Result:Seven literatures of case-control study were included. The Meta analysis showed that: After the thyroid hormone replacement, the patient's AHI index, TSH index, LSaO₂ index were significantly improved (P< 0.05). The AHI index statistical results of the patients were [SMD= 3.15, 95%CI: (4.36-1.94), P< 0.000 01; I²= 96%], TSH index were [SMD= 4.15,95%CI: (1.15-7.15), P= 0.007; I²= 99%], LSaO₂ index were [SMD=-1.08, 95%CI: (-1.46--0.70), P< 0.000 01, I²= 68%].Conclusion:The use of thyroid hormone replacement can effectively reduce the patient's hypothyroidism symptoms and AHI symptoms.

[Degeneration and regeneration characteristics of nerves and muscles after recurrent laryngeal nerve injury]

Objective:We investigated the degeneration and regeneration characteristics of nerves and muscles after different degrees of recurrent laryngeal nerve (RLN) injury, and then discussed the possible relations between them. Method:Ninety-five Sprague Dawley (SD) rats were used in this study, 2 rats died of infection, 2 died during surgery and 1 died in transit. The rest 90 SD rats were classified as having complete injuries (transection,43 rats), incomplete injuries (crush, 43 rats) and conrtol group (4 rats). The characteristics of nerve injuries were evaluated by endoscopic examination, laryngeal electromyography (LEMG), and histopathologic examination at 6 hours, 12 hours, 1 day, 3 day, 5 day, 1 week, 2 weeks, 3 weeks and 4 weeks after the injury. Result:All the vocal folds kept fixation in the completely injury group, where as 41/43 vocal folds in imcompletely injury group got normal activity 2 weeks after surgery, 1 at 3 weeks and 1 at 4 weeks. Fibrillation potentials were found 1 day after transection, and rennervation potentials appeared 4 weeks after transection. LEMG was normal 3 weeks after RLN was crushed. The average muscle fiber number of the left thyroarytenoid (TA) decreased with the time in the completely injury group, which increased in the second week after crush. Degeneration appeared more seriously in the distal region after transaction, and a small amount of large myelinated nerve fibers appeared at 4 weeks after injury. The most serious nerve degeneration appeared in the first day after crush, and 1 week later the ultrastructures of RLN were almost normal. The phagocytosis of Schwann cells occurred within 2 weeks after injury, 3 weeks later we found the apperance of Schwann cells who did not wrap around nerve fibers, especially in the proximal region. In the crush group, the phagocytosis of Schwann cells occurred within 1 week after injury, apoptosis and degeneration appered occasionally. Inflammatory response was more severe in the transection group, the number of fibroblasts and collagen fibers in the mesenchy increased. Conclusion:The degeneration is more severe in the distal nerve when RLN is traversed. Nerve regeneration appears in the fourth week after RLN is traversed. Injuried nerve has the ability to repair itself. Schwann cells play a role in phagocytosis after injury, and immature Schwann cells are found. Nerve fiber disintegration product can accelerate the migration of macrophage activation.

Targeting C3a/C5a receptors inhibits human mesangial cell proliferation and alleviates immunoglobulin A nephropathy in mice

Complement activation has a deep pathogenic influence in immunoglobulin (Ig)A nephropathy (IgAN). C3a and C5a, small cleavage fragments generated by complement activation, are key mediators of inflammation. The fragments exert broad proinflammatory effects by binding to specific receptors (C3aR and C5aR, respectively). However, no studies thus far have investigated the effects of C3a, C5a and their receptors on IgAN. We observed that C3aR and C5aR antagonists repressed IgA-induced cell proliferation and interleukin (IL)-6 and monocyte chemotactic protein 1 (MCP-1) production in cultured human mesangial cells (HMCs). Furthermore, an IgAN mouse model induced by Sendai virus infection was employed to investigate the effects of C3aR and C5aR on IgAN in vivo for the first time. Wild-type (WT) and several knock-out mouse strains (C3aR^-/- or C5aR^-/- ) were immunized intranasally with increasing doses of inactivated virus for 14 weeks and were subjected to two intravenous viral challenges during the time-period indicated. In the Sendai virus-induced IgAN model, C3aR/C5aR-deficient mice had significantly reduced proteinuria, lower renal IgA and C3 deposition, less histological damage and reduced mesangial proliferation compared with WT mice. Both C3aR deficiency and C5aR deficiency, especially C3aR deficiency, inhibited renal tumour necrosis factor (TNF)-α, transforming growth factor (TGF)-β, IL-1β, IL-6 and MCP-1 expression significantly. However, C3aR/C5aR-deficient and WT mice with IgAN did not differ with respect to their blood urea nitrogen (BUN) and serum creatinine levels. Our findings provide further support for the idea that C3aR and C5aR are crucially important in IgAN, and suggest that pharmaceutically targeting C3aR/C5aR may hold promise for the treatment of IgAN.

Spodoptera litura autophagy-related protein 1 interacts with autophagy-related protein 5 and enhances its degradation

It is known that the autophagy-related protein 1 (ATG1) plays critical roles in the regulation of autophagy in mammals and yeast, whereas the function of ATG1 in lepidopteran insects is not well elucidated. Here Spodoptera litura ATG1 (SlATG1) and its interactions with other ATG proteins were characterized. Alternative splicing of SlAtg1 produced at least four transcript variants. Over-expression and RNA interference knockdown of SlAtg1 demonstrated that SlATG1 enhanced autophagy. SlATG1A-Green fluorescent protein (GFP) tagged localized in the cytoplasm and formed some punctuate dots, which were colocalized with red fluorescent protein mCherry tagged Spodoptera exigua ATG5 (SeATG5). SlATG1A-GFP over-expression reduced the nuclear abundance of mCherry-SeATG5 but increased its cytoplasmic abundance. Pull-down, co-immunoprecipitation and bimolecular fluorescence complementation assays showed that SlATG1A bound to SeATG5 through the N-terminus of SlATG1A. The over-expression of FLAG epitope tagged SlATG1A significantly increased the accumulation of the cleaved GFP from GFP-SeATG5, suggesting the enhanced degradation of GFP-SeATG5. In addition, we confirmed that the interactions of SlATG1 with other autophagy-related proteins were conserved. These results provide the first evidence that ATG1 interacts with ATG5 and enhances its degradation in lepidopteran insect cells, which may have important physiological functions.

Preconditioning-induced CXCL12 upregulation minimizes leukocyte infiltration after stroke in ischemia-tolerant mice

Repetitive hypoxic preconditioning creates long-lasting, endogenous protection in a mouse model of stroke, characterized by reductions in leukocyte-endothelial adherence, inflammation, and infarct volumes. The constitutively expressed chemokine CXCL12 can be upregulated by hypoxia and limits leukocyte entry into brain parenchyma during central nervous system inflammatory autoimmune disease. We therefore hypothesized that the sustained tolerance to stroke induced by repetitive hypoxic preconditioning is mediated, in part, by long-term CXCL12 upregulation at the blood-brain barrier (BBB). In male Swiss Webster mice, repetitive hypoxic preconditioning elevated cortical CXCL12 protein levels, and the number of cortical CXCL12+ microvessels, for at least two weeks after the last hypoxic exposure. Repetitive hypoxic preconditioning-treated mice maintained more CXCL12-positive vessels than untreated controls following transient focal stroke, despite cortical decreases in CXCL12 mRNA and protein. Continuous administration of the CXCL12 receptor (CXCR4) antagonist AMD3100 for two weeks following repetitive hypoxic preconditioning countered the increase in CXCL12-positive microvessels, both prior to and following stroke. AMD3100 blocked the protective post-stroke reductions in leukocyte diapedesis, including macrophages and NK cells, and blocked the protective effect of repetitive hypoxic preconditioning on lesion volume, but had no effect on blood-brain barrier dysfunction. These data suggest that CXCL12 upregulation prior to stroke onset, and its actions following stroke, contribute to the endogenous, anti-inflammatory phenotype induced by repetitive hypoxic preconditioning.

Abstract P3-04-12: Both spliced and unspliced XBP1 regulates breast cancer cell fate response to antiestrogen via NFkappaB signaling

Unfolded protein response (UPR), a stress-induced survival mechanism, may be used by cancer cells to avoid cell death. Antiestrogen therapy, widely applied in the treatment of estrogen receptor-positive (ER+) breast cancer, induces endoplasmic reticulum stress (EnR stress) that leads to activation of each of the three arms of the UPR. One critical prosurvival activator that is regulated by two arms of the UPR is the transcription factor X-box binding protein 1 (XBP1). XBP1 exists in two isoforms, the transcriptionally inactive unspliced XBP1(U) and the spliced, active XBP1(S). Overexpression of XBP1(S) confers estrogen independence and antiestrogen resistance in ER+ breast cancer cells and XBP1(S) expression correlates with poor clinical responsiveness to Tamoxifen in ER+ breast tumors. However, the underlying signaling mechanisms regulated by XBP1, which may mediate its effects on antiestrogen resistance, are unknown. We show that depletion of endogenous XBP-1 by siRNA increases apoptosis, decreases autophagy, requires down-regulation of p65/RelA, a component of the pro-survival NFκB complex. Using novel spliced and non-spliceable forms of XBP1, we show that XBP1(U) and XBP1(S) both regulate NFκB activity via ERα signaling in breast cancer cells. XBP1(S), but not XBP1(U), also can regulate p65/RelA expression independent of ERα. Antiestrogen resistance as conferred by XBP1 overexpression in MCF-7 cells requires the activation of NFκB signaling; inhibition of NFκB signaling by either the small molecule NFκB inhibitor Parthenolide or p65/RelA siRNA sensitizes XBP1 overexpressing cells to Tamoxifen. The activation of XBP1 and the downstream NFκB signaling is likely to contribute to the TMEM33 overepxression induced apoptosis, as both NFκB signaling and XBP1(S) are elevated in TMEM33 overexpressed MCF7 cells. Thus, we have identified a critical regulatory link between the UPR/XBP1 pathway and pro-survival NFκB signaling that is a major contributor to endocrine responsiveness in ER positive breast cancer.

Citation Format: Clarke R, Hu R, Warri A, Jin L, Zwart A, Riggins R, Fang H-b. Both spliced and unspliced XBP1 regulates breast cancer cell fate response to antiestrogen via NFkappaB signaling [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-12.

Abstract P4-10-02: Transmembrane protein 33 (TMEM33) induces apoptosis via UPR signaling and autophagy in breast cancer cells

Breast cancer is the most common cancer diagnosed in women. Endoplasmic reticulum stress (EnR stress) and the related unfolded protein response (UPR) are activated in breast cancer cells and can promote cell survival and endocrine resistance. TMEM33 is a novel transmembrane protein that resides in the endoplasmic reticulum (EnR) and has been shown to activate the PERK and IRE1α branches of the UPR. However, the underlying mechanism of action of this EnR resident protein TMEM33 and the cellular functions that it regulates remain largely unknown. In this study, we show that overexpression of TMEM33 induces robust cell death in breast cancer cells. TMEM33 overexpression strongly activates UPR associated pro-death JNK-p53 signaling. We also observed a significant inhibition of the downstream survivin, which blocks cell death activation by binding to caspases and inhibiting their activation. We further show that the blockage of JNK activation with either an inhibitor or overexpression of survivin, protects cells against TMEM33 induced apoptosis. In addition, we show that TMEM33 overexpression induces autophagy in breast cancer cells. Inhibition of autophagy with using either the inhibitor chloroquine or knockdown of the Atg5 gene, further sensitizes breast cancer cells to the effects of TMEM33 overexpression. Cell death induced by TMEM33 is also decreased by overexpression of the autophagy gene Beclin 1. The findings in this study demonstrate that the novel EnR resident protein TMEM33 induces cell death by activating IRE1α-JNK-p53-survivin signaling in breast cancer cells. Concurrently, autophagy is also activated by TMEM33, and functions as a pro-survival mechanism. Cell fate reflects the balance between the pro-death and pro-survival activities as regulated by TMEM33.

Citation Format: Clarke R, Hu R, Zhang X, Hilakivi-Clarke L, Kasid U. Transmembrane protein 33 (TMEM33) induces apoptosis via UPR signaling and autophagy in breast cancer cells [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-10-02.

BN nanoflake quantum-dot arrays: structural stability, and electronic and half-metallic properties

One-dimensional arrays constructed by triangular h-BN nanoflakes are studied. It is found that the linking manner plays a crucial role in electronic and half-metallic properties and the traversed electric field further enhances half-metallicity.

[The relevance between obstructive sleep apnea hypopnea syndrome andchronic obstructive pulmonary disease in China: A Meta-analysis]

Objective:To assess the correlation between obstructive sleep apnea hypopnea syndrome(OSAHS) and chronic obstructive pulmonary disease(COPD).Method: Databases such as Chinese Biomedical Literature Database, PubMed, Chinese Academic Journals full-text database, Wanfang Resource Database and Chongqing VIP have been searched to collect literatures about the relationship between OSAHS and COPD. The literature in conference proceedings and certain unpublished articles were also manually retrieved. RCT conformed to the condition was evaluated according to the standards of literature assessment, and the data has been extracted. The RevMan5.3 software was applied to carry out the same Metaanalysis.Result: Totally 19 articles were included, and Metaanalysis reveal that overlap syndrome(OS) patient's apnea hypopnea index is significantly higher than those of OSAHS patients［WMD=7.56, 95%CI（4.19,10.94）, P<0.01］; The LSaO₂ of OS patients is significantly lower than OSAHS patients［WMD=-10.50, 95%CI(-11.58, -6.08),P<0.01］; OS patients' FEV₁/FVC is significantly lower than COPD patients［WMD=4.65,95%CI（1.15,8.15）,P<0.01］.The results revealed that subgroup analysis according to the sample volume, age, body mass index(BMI) and FEV₁/FVC between OS patients and OSAHS patients has heterogeneity, but when analysis with the score of ESS the heterogeneity does not exist. Further, the subgroup analysis according to the sample volume, BMI, AHI,LSaO₂ and the time of Oxygen is lower than 90%(T90) those index between OS patients and COPD patients has heterogeneity, and the heterogeneity does not exist when subgroup is analyses with neck circumference. The funnel schema was nearly symmetry with little bias.Conclusion:The experimental results indicate that OSAHS is significantly related with COPD, and they may be the mutual risk factor for each other..

Hyperpolarization-Activated Currents and Subthreshold Resonance in Granule Cells of the Olfactory Bulb

An important contribution to neural circuit oscillatory dynamics is the ongoing activation and inactivation of hyperpolarization-activated currents (Ih). Network synchrony dynamics play an important role in the initial processing of odor signals by the main olfactory bulb (MOB) and accessory olfactory bulb (AOB). In the mouse olfactory bulb, we show that Ih is present in granule cells (GCs), the most prominent inhibitory neuron in the olfactory bulb, and that Ih underlies subthreshold resonance in GCs. In accord with the properties of Ih, the currents exhibited sensitivity to changes in extracellular K+ concentration and ZD7288 (4-ethylphenylamino-1,2-dimethyl-6-methylaminopyrimidin chloride), a blocker of Ih. ZD7288 also caused GCs to hyperpolarize and increase their input resistance, suggesting that Ih is active at rest in GCs. The inclusion of cAMP in the intracellular solution shifted the activation of Ih to less negative potentials in the MOB, but not in the AOB, suggesting that channels with different subunit composition mediate Ih in these regions. Furthermore, we show that mature GCs exhibit Ih-dependent subthreshold resonance in the theta frequency range (4-12 Hz). Another inhibitory subtype in the MOB, the periglomerular cells, exhibited Ih-dependent subthreshold resonance in the delta range (1-4 Hz), while principal neurons, the mitral cells, do not exhibit Ih-dependent subthreshold resonance. Importantly, Ih size, as well as the strength and frequency of resonance in GCs, exhibited a postnatal developmental progression, suggesting that this development of Ih in GCs may differentially contribute to their integration of sensory input and contribution to oscillatory circuit dynamics.

Cyclic adenosine monophosphate-protein kinase A signal pathway may be involved in pulmonary aquaporin-5 expression in ischemia/reperfusion rats following deep hypothermia cardiac arrest

We investigated the effects of cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) on the expression of aquaporin 5 (AQP5) in ischemia/reperfusion (I/R) rats following deep hypothermia cardiac arrest. Wistar rats were randomly divided into: a sham control group (subjected to a sham operation); an I/R group (subjected to occlusion of the bronchial arteries and the left inferior pulmonary artery); an H89 group (subjected to occlusion of the bronchial arteries and the left inferior pulmonary vein and artery, and treated with 5 mg/kg H89 for 2 days before the study); and a forskolin group (subjected to occlusion of the bronchial arteries and the left inferior pulmonary vein and artery, and treated with 5 mg/kg forskolin for 2 days before the study). Expression levels of AQP5 mRNA and protein were determined using reverse transcription-polymerase chain reaction and western blotting. Decreased expression of AQP5 was noted in the pulmonary tissues of the I/R group compared with the sham controls. Compared to that in the control group, there was a notable decrease in AQP5 expression in the I/R group. After treating with forskolin, AQP5 expression increased in the forskolin group compared with the I/R group. In the H89 group, AQP5 expression decreased compared with the I/R group. The decreased expression of AQP5 was possibly associated with acute pulmonary injury induced by I/R. The cAMP-PKA signal pathway may be involved in the expression of AQP5 in I/R rats after deep hypothermia cardiac arrest.