Cold-inducible RNA-binding protein mediates airway inflammation and mucus hypersecretion through a post-transcriptional regulatory mechanism under cold stress

The extracellular CIRP as a predictive marker for the endothelial dysfunction in chronic obstructive pulmonary disease combined with pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) is a serious complication of chronic obstructive pulmonary disease (COPD), distinguished by pulmonary endothelial dysfunction. The extracellular cold-inducible RNA-binding protein (eCIRP) is a damage-associated molecular pattern (DAMP) that triggers inflammation and causes vascular endothelial dysfunction in COPD-PH.

METHODS

The expression levels of CIRP were compared in peripheral lung tissues among 40 individuals. Moreover, A prospective analysis was conducted on serum levels of eCIRP, interleukin (IL) 1β, IL-33, endothelin-1 (ET-1), and nitric oxide (NO) in 150 COPD patients and 50 healthy control individuals at Jiangsu Taizhou Peoples Hospital. The study aimed to compare these serum levels and correlations among COPD-PH group, COPD non-PH group and the normal group.

RESULTS

We found higher CIRP levels in COPD-PH compared to COPD non-PH and the normal in lung tissue samples. A prospective analysis showed higher serum levels of eCIRP, IL-1β, IL-33, and ET 1 in COPD-PH, while a noticeable reduction in NO levels. There exists a correlation between the severity of COPD-PH and elevated levels of eCIRP, proinflammatory cytokines like IL-1β and IL-33, along with indicators of endothelial dysfunction like endothelin-1 ET-1 and NO. Moreover, the serum eCIRP level demonstrated a notable positive correlation with the levels of IL-1β, IL-33, PCT, and ET-1, while displaying a negative correlation with NO and Peripheral Oxygen Saturation (SpO2). Moreover, the serum eCIRP level demonstrated a notable positive correlation with the levels of IL-1β, IL-33, PCT, and ET-1, while displaying a negative correlation with NO and SpO2. Moreover, an assessment of independent risk factors for COPD-PH with ROC curve analysis, gauged the predictive value of serum eCIRP, IL-1β, IL-33, ET-1, and NO levels in diagnosing COPD-PH. Elevated eCIRP, IL-33, and ET-1 levels significantly correlated with COPD-PH, highlighting eCIRP's strong predictive value for this condition.

CONCLUSION

eCIRP levels could serve as a valuable biomarker for predicting endothelial dysfunction in COPD-PH.

Stellate Ganglion Block Attenuates LPS-Induced Acute Lung Injury by Activating Sirt3 Regulation of Oxidative Stress and Inflammation

Stellate ganglion blocks (SGBs) has been applied in clinics to alleviate pain-related syndromes for almost a century. In recent years, it has been reported that SGB can attenuate acute lung injury (ALI) in animals. However, the details of these molecular mechanisms remain complex and unclear. In this study, rats were randomly divided into four groups: group C (receiving no treatment), group NS (receiving the intratracheal instillation of normal saline), group L (receiving the intratracheal instillation of LPS) and group LS (receiving SGB after the intratracheal instillation of LPS). The pathological damage of lung tissue, arterial blood gases, the differentiation of alveolar macrophages (AMs) and inflammatory cytokines (IL-1β, IL-6, IL-10) were detected. Furthermore, the oxidative stress indexes (ROS, CYP-D, T-SOD, Mn-SOD and CAT) in serum and the levels of Sirt3 signaling-associated proteins (JAK2/STAT3, NF-κb p65, CIRP and NLRP3) in the lungs were measured. The results revealed that SGB could attenuate lung tissue damage, improve pulmonary oxygenation, promote the differentiation of AMs to the M2 phenotype, decrease the secretion of IL-1β and IL-6, and increase the secretion of IL-10. Meanwhile, SGB was found to inhibit the production of ROS and CYP-D, and enhance the activities of T-SOD, Mn-SOD and CAT. Furthermore, SGB upregulated Sirt3 and downregulated JAK2/STAT3 and NF-κb p65 phosphorylation, CIRP and NLRP3. Our work revealed that SGB could attenuate LPS-induced ALI by activating the Sirt3-mediated regulation of oxidative stress and pulmonary inflammation; this may shed new light upon the protection of SGB and provide a novel prophylactic strategy for LPS-induced ALI.

Cold-Inducible RNA Binding Protein Impedes Breast Tumor Growth in the PyMT Murine Model for Breast Cancer

RNA binding proteins (RBPs) post-transcriptionally regulate gene expression by associating with regulatory sequences in the untranslated regions of mRNAs. Cold-inducible RBP (CIRP) is a stress-induced RBP that was recently shown to modulate inflammation in response to cellular stress, where it increases or decreases pro-tumorigenic (proinflammatory) cytokines in different contexts. CIRP expression is altered in several cancers, including breast cancer, but the effects of CIRP on inflammation in breast cancer is not known. Here, we investigate if CIRP alters growth and the inflammatory profile of breast tumors. Transgenic mice overexpressing CIRP in the mammary epithelium were crossed with the PyMT mouse model of breast cancer, and the effects on both early and late tumorigenesis and inflammation were assessed. The effects of CIRP knockdown were also assessed in Py2T cell grafts. Overexpression of CIRP led to decreased tumorigenesis in the PyMT mouse model. Conversely, the knockdown of CIRP in Py2T cell grafts led to increased tumor growth. Luminex cytokine assays assessed the effects on the inflammatory environment. CIRP/PyMT mammary glands/mammary tumors and serum had decreased cytokines that promote inflammation, angiogenesis, and metastasis compared to PyMT mammary glands and serum, documenting a shift towards an environment less supportive of tumorigenesis. CIRP overexpression also decreased CD4+ helper T cells and increased CD8+ cytotoxic T cells in mammary tumors. Overall, these data support a role for CIRP as a potent antitumor molecule that suppresses both local and systemic pro-tumorigenic inflammation.

RNA-Binding Proteins as a Molecular Link between COPD and Lung Cancer

Chronic obstructive pulmonary disease (COPD) represents an independent risk factor for lung cancer development. Accelerated cell senescence, induced by oxidative stress and inflammation, is a common pathogenic determinant of both COPD and lung cancer. The post transcriptional regulation of genes involved in these processes is finely regulated by RNA-binding proteins (RBPs), which regulate mRNA turnover, subcellular localization, splicing and translation. Multiple pro-inflammatory mediators (including cytokines, chemokines, proteins, growth factors and others), responsible of lung microenvironment alteration, are regulated by RBPs. Several mouse models have shown the implication of RBPs in multiple mechanisms that sustain chronic inflammation and neoplastic transformation. However, further studies are required to clarify the role of RBPs in the pathogenic mechanisms shared by lung cancer and COPD, in order to identify novel biomarkers and therapeutic targets. This review will therefore focus on the studies collectively indicating the role of RBPs in oxidative stress and chronic inflammation as common pathogenic mechanisms shared by lung cancer and COPD.

RNA-binding proteins in degenerative joint diseases: A systematic review

RNA-binding proteins (RBPs), which are conserved proteins comprising multiple intermediate sequences, can interact with proteins, messenger RNA (mRNA) of coding genes, and non-coding RNAs to perform different biological functions, such as the regulation of mRNA stability, selective polyadenylation, and the management of non-coding microRNA (miRNA) synthesis to affect downstream targets. This article will highlight the functions of RBPs, in degenerative joint diseases (intervertebral disc degeneration [IVDD] and osteoarthritis [OA]). It will reviews the latest advancements on the regulatory mechanism of RBPs in degenerative joint diseases, in order to understand the pathophysiology, early diagnosis and treatment of OA and IVDD from a new perspective.

A Comparative Study to Explore Static and Dynamic Lung Functions in Users and Non-Users of Air Conditioners in Bengaluru

Background

Air conditioners (AC) have become indispensable in the contemporary World. However, their effects on respiratory health need to be explored further using dynamic and static lung functions.

Objectives

The objectives were: 1. To evaluate and compare dynamic parameters (FEV1, FVC, FEV1/FVC, PEFR, and FEF25-75) in AC users and non-users of Bengaluru. 2. To evaluate and compare airway resistance and specific airway conductance as additional parameters.

Materials and Methods

After applying ATS-ERS criteria for lung disorders, 30 AC users and non-users of Bengaluru, aged 18-40 yrs were assessed using body plethysmography. A significant association of restrictive pattern was seen in AC users (9 AC users out of 60 participants, Chi-square 8.37, P = 0.0038) having an Odd's ratio of 26.95 (CI: 1.4876 to 488.3558, Z = 2.229, P = 0.0258). Airway resistance (Raw) was comparable in both groups further indicating a non-obstructive pathology.

Conclusion

AC users had a significant decrease in flow rates (PEFR and FEF25-75) as well as an association with restrictive lung disorder suggesting the need for proper ventilation and hygiene. It is crucial to develop policies to maintain indoor air quality.

Association between ambient cold exposure and mortality risk in Shandong Province, China: Modification effect of particulate matter size

Introduction

Numerous studies have reported the modification of particulate matters (PMs) on the association between cold temperature and health. However, it remains uncertain whether the modification effect may vary by size of PMs, especially in Shandong Province, China where the disease burdens associated with cold temperature and PMs are both substantial. This study aimed to examine various interactive effects of cold exposure and ambient PMs with diameters ≤1/2.5 μm (PM1 and PM2.5) on premature deaths in Shandong Province, China.

Methods

In the 2013-2018 cold seasons, data on daily mortality, PM1 and PM2.5, and weather conditions were collected from the 1822 sub-districts of Shandong Province. A time-stratified case-crossover study design was performed to quantify the cumulative association between ambient cold and mortality over lag 0-12 days, with a linear interactive term between temperature and PM1 and PM2.5 additionally added into the model.

Results

The mortality risk increased with temperature decline, with the cumulative OR of extreme cold (-16.9°C, the 1st percentile of temperature range) being 1.83 (95% CI: 1.66, 2.02), compared with the minimum mortality temperature. The cold-related mortality risk was 2.20 (95%CI: 1.83, 2.64) and 2.24 (95%CI: 1.78, 2.81) on high PM1 and PM2.5 days, which dropped to 1.60 (95%CI: 1.39, 1.84) and 1.60 (95%CI: 1.37, 1.88) on low PM1 and PM2.5 days. PM1 showed greater modification effect for per unit concentration increase than PM2.5. For example, for each 10?g/m3 increase in PM1 and PM2.5, the mortality risk associated with extreme cold temperature increased by 7.6% (95% CI: 1.3%, 14.2%) and 2.6% (95% CI: -0.7%, 5.9%), respectively.

Discussion

The increment of smaller PMs' modification effect varied by population subgroups, which was particularly strong in the elderly aged over 75 years and individuals with middle school education and below. Specific health promotion strategies should be developed towards the greater modification effect of smaller PMs on cold effect.

Exosome-derived CIRP: An amplifier of inflammatory diseases

Cold-inducible RNA-binding protein (CIRP) is an intracellular stress-response protein and a type of damage-associated molecular pattern (DAMP) that responds to various stress stimulus by altering its expression and mRNA stability. Upon exposure to ultraviolet (UV) light or low temperature, CIRP get translocated from the nucleus to the cytoplasm through methylation modification and stored in stress granules (SG). During exosome biogenesis, which involves formation of endosomes from the cell membrane through endocytosis, CIRP also gets packaged within the endosomes along with DNA, and RNA and other proteins. Subsequently, intraluminal vesicles (ILVs) are formed following the inward budding of the endosomal membrane, turning the endosomes into multi-vesicle bodies (MVBs). Finally, the MVBs fuse with the cell membrane to form exosomes. As a result, CIRP can also be secreted out of cells through the lysosomal pathway as Extracellular CIRP (eCIRP). Extracellular CIRP (eCIRP) is implicated in various conditions, including sepsis, ischemia-reperfusion damage, lung injury, and neuroinflammation, through the release of exosomes. In addition, CIRP interacts with TLR4, TREM-1, and IL-6R, and therefore are involved in triggering immune and inflammatory responses. Accordingly, eCIRP has been studied as potential novel targets for disease therapy. C23 and M3, polypeptides that oppose eCIRP binding to its receptors, are beneficial in numerous inflammatory illnesses. Some natural molecules such as Luteolin and Emodin can also antagonize CIRP, which play roles similar to C23 in inflammatory responses and inhibit macrophage-mediated inflammation. This review aims to provide a better understanding on CIRP translocation and secretion from the nucleus to the extracellular space and the mechanisms and inhibitory roles of eCIRP in diverse inflammatory illnesses.

Human Protein Arginine Methyltransferases (PRMTs) Can Be Optimally Active Under Non-Physiological Conditions

Protein arginine methylation is involved in many biological processes and can be enhanced in cancer. In mammals, these reactions are catalyzed on multiple substrates by a family of nine protein arginine methyltransferases (PRMTs). However, conditions that may regulate the activity of each enzyme and that may help us understand the physiological role of PRMTs have not been fully established. Previous studies had suggested unexpected effects of temperature and ionic strength on PRMT7 activity. Here we examine in detail the effects of temperature, pH, and ionic strength on recombinant human PRMT1, PRMT5, and PRMT7. We confirmed the unusual temperature dependence of PRMT7, where optimal activity was observed at 15 °C. On the other hand, we found that PRMT1 and PRMT5 are most active near physiological temperatures of 37 °C. However, we showed all three enzymes still have significant activity at 0 °C. Furthermore, we determined that PRMT1 is most active at a pH of about 7.7, while PRMT5 activity is not dependent on pH in the range of 6.5 to 8.5. Significantly, PRMT7 is most active at an alkaline pH of 8.5 but shows little activity at the physiological intracellular pH of about 7.2. We also detected decreased activity at physiological salt conditions for PRMT1, PRMT5, and PRMT7. We demonstrate that the loss of activity is due to the increasing ionic strength. Taken together, these results open the possibility that PRMTs respond in cells undergoing temperature, salt, or pH stress and demonstrate the potential for in vivo regulation of protein arginine methylation.

Associations between ambient temperature and adult asthma hospitalizations in Beijing, China: a time-stratified case-crossover study

Background

Studies on the associations between ambient temperature and asthma hospitalizations are limited, and the results are controversial. We aimed to assess the short-term effects of ambient temperature on the risk of asthma hospitalizations and quantify the hospitalization burdens of asthma attributable to non-optimal temperature in adults in Beijing, China.

Methods

We collected daily asthma hospitalizations, meteorological factors and air quality data in Beijing from 2012 to 2015. We applied a time-stratified case-crossover design and fitted a distributed lag non-linear model with a conditional quasi-Poisson regression to explore the association between ambient temperature and adult asthma hospitalizations. The effect modifications of these associations by gender and age were assessed by stratified analyses. We also computed the attributable fractions and numbers with 95% empirical confidence intervals (eCI) of asthma hospitalizations due to extreme and moderate temperatures.

Results

From 2012 to 2015, we identified a total of 18,500 hospitalizations for asthma among adult residents in Beijing, China. Compared with the optimal temperature (22 °C), the cumulative relative risk (CRR) over lag 0–30 days was 2.32 with a 95% confidence interval (CI) of 1.57–3.42 for extreme cold corresponding to the 2.5th percentile (− 6.5 °C) of temperature distribution and 2.04 (95% CI 1.52–2.74) for extreme heat corresponding to the 97.5th percentile (29 °C) of temperature distribution. 29.1% (95% eCI 17.5–38.0%) of adult asthma hospitalizations was attributable to non-optimum temperatures. Moderate cold temperatures yielded most of the burdens, with an attributable fraction of 20.3% (95% eCI 9.1–28.7%). The temperature-related risks of asthma hospitalizations were more prominent in females and younger people (19–64 years old).

Conclusions

There was a U-shaped association between ambient temperature and the risk of adult asthma hospitalizations in Beijing, China. Females and younger patients were more vulnerable to the effects of non-optimum temperatures. Most of the burden was attributable to moderate cold. Our findings may uncover the potential impact of climate changes on asthma exacerbations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01960-8.

The role of Cold-Inducible RNA-binding protein in respiratory diseases

Cold‐inducible RNA‐binding protein (CIRP) is a stress‐response protein that is expressed in various types of cells and acts as an RNA chaperone, modifying the stability of its targeted mRNA. Intracellular CIRP could also be released into extracellular space and once released, extracellular CIRP (eCIRP) acts as a damage‐associated molecular pattern (DAMP) to induce and amplify inflammation. Recent studies have found that eCIRP could promote acute lung injury (ALI) via activation of macrophages, neutrophils, pneumocytes and lung vascular endothelial cells in context of sepsis, haemorrhagic shock, intestinal ischemia/reperfusion injury and severe acute pancreatitis. In addition, CIRP is also highly expressed in the bronchial epithelial cells and its expression is upregulated in the bronchial epithelial cells of patients with chronic obstructive pulmonary diseases (COPD) and rat models with chronic bronchitis. CIRP is a key contributing factor in the cold‐induced exacerbation of COPD by promoting the expression of inflammatory genes and hypersecretion of airway mucus in the bronchial epithelial cells. Besides, CIRP is also involved in regulating pulmonary fibrosis, as eCIRP could directly activate and induce an inflammatory phenotype in pulmonary fibroblast. This review summarizes the findings of CIRP investigation in respiratory diseases and the underlying molecular mechanisms.

Cold-inducible RNA-binding protein regulates cyclin B1 against spermatogenesis arrest caused by heat stress

BACKGROUND

Spermatogenesis arrest and spermatogenic cell apoptosis occur in the testes of heat-stressed mice. Although heat stress-induced spermatogenic cell apoptosis is due to the decreased expression of cold-inducible RNA-binding protein (CIRBP), it remains unclear whether spermatogenesis arrest is also affected by CIRBP. Additionally, the specific mechanism by which CIRBP regulates spermatogenic cell apoptosis or inhibits spermatogenesis remains to be elucidated.

OBJECTIVES

To investigate the mechanism by which CIRBP contributes to heat stress-induced testicular spermatogenesis arrest.

MATERIALS AND METHODS

Target mRNAs downstream of CIRBP in testicular tissue of BALB/c mice, exposed or not to heat stress, were sequenced. Sequencing data were subjected to bioinformatics analysis to identify key mRNAs and pathways associated with heat stress-induced spermatogenic damage. The link between CIRBP and its target mRNA Ccnb1 (cyclin B1) was verified by western blotting, flow cytometry, and RNA pulldown assays, and the ability of CIRBP to inhibit germ cell cycle arrest by regulating cyclin B1 expression was investigated in a mouse spermatocyte cell line (GC-2spd).

RESULTS

Changes in mRNA expression downstream of CIRBP were mainly associated with the cell cycle and RNA binding, transport and splicing. Cyclin B1 was found to regulate the G2/M transition during the first meiotic division of spermatogenic cells. Further, CIRBP was shown to bind directly to the 3'-untranslated region of Ccnb1 mRNA and was associated with cyclin B1-induced inhibition of spermatogenesis arrest.

DISCUSSION AND CONCLUSION

In conclusion, our results provide strong evidence that CIRBP may exert its key function in heat stress-induced testicular spermatogenic cell injury partly by regulating the expression of Ccnb1, the product of which inhibits spermatogenesis arrest.

Increased hospital admissions for asthma from short-term exposure to cold spells in Beijing, China

BACKGROUND

There is a paucity of studies investigating extreme cold events and asthma exacerbations. This study examined whether an association exists between cold spells and daily hospital admissions for asthma in Beijing, China from 2012 to 2016.

METHODS

Daily hospital admissions for asthma, meteorological variables and air quality data were collected during 2012-2016 in Beijing. A cold spell was defined as a period of at least two consecutive days with the daily mean temperature below or at the 5th percentile (-7 °C) in cold seasons (November to March) during the study period. We applied a time-series design using quasi-Poisson regression combined with a distributed lag model to estimate the risk of asthma hospital admissions associated with cold spells. Stratified analyses by gender and age groups were conducted to identify the potential susceptible subpopulations to cold spells. We also explored the effect modification by air quality by dividing the daily air quality index (AQI) into two levels (high and low) based on the median value.

RESULTS

Cold spells increased the risk of asthma hospital admissions, with the maximum cumulative relative risk (CRR) over three weeks (Lag0-21) in the total population. The highest single-day relative risk (RR) was found on the days of cold spells (Lag0) with the RR = 1.059 (95% CI: 1.008-1.113), and the CRR at Lag0-21 was 1.333 (95% CI: 1.049-1.693). Across different gender and age groups, younger people (<65 years) were more sensitive to cold spells. No significant effect modification by AQI was detected.

CONCLUSION

Short-term exposure to cold spells is associated with an increased risk of hospital admissions for asthma in Beijing. During the cold spells, younger people aged <65 years were at particular risk for asthma exacerbations. Our results suggest that extreme cold events have a significant impact on asthma.

CIRP promotes the progression of non-small cell lung cancer through activation of Wnt/β-catenin signaling via CTNNB1

BACKGROUND

Cold-inducible RNA binding protein (CIRP) is a newly discovered proto-oncogene. In this study, we investigated the role of CIRP in the progression of non-small cell lung cancer (NSCLC) using patient tissue samples, cultured cell lines and animal lung cancer models.

METHODS

Tissue arrays, IHC and HE staining, immunoblotting, and qRT-PCR were used to detect the indicated gene expression; plasmid and siRNA transfections as well as viral infection were used to manipulate gene expression; cell proliferation assay, cell cycle analysis, cell migration and invasion analysis, soft agar colony formation assay, tail intravenous injection and subcutaneous inoculation of animal models were performed to study the role of CIRP in NSCLC cells; Gene expression microarray was used to select the underlying pathways; and RNA immunoprecipitation assay, biotin pull-down assay, immunopurification assay, mRNA decay analyses and luciferase reporter assay were performed to elucidate the mechanisms. The log-rank (Mantel-Cox) test, independent sample T-test, nonparametric Mann-Whitney test, Spearman rank test and two-tailed independent sample T-test were used accordingly in our study.

RESULTS

Our data showed that CIRP was highly expressed in NSCLC tissue, and its level was negatively correlated with the prognosis of NSCLC patients. By manipulating CIRP expression in A549, H460, H1299, and H1650 cell lines, we demonstrated that CIRP overexpression promoted the transition of G1/G0 phase to S phase and the formation of an enhanced malignant phenotype of NSCLC, reflected by increased proliferation, enhanced invasion/metastasis and greater tumorigenic capabilities both in vitro and in vivo. Transcriptome sequencing further demonstrated that CIRP acted on the cell cycle, DNA replication and Wnt signaling pathway to exert its pro-oncogenic action. Mechanistically, CIRP directly bound to the 3'- and 5'-UTRs of CTNNB1 mRNA, leading to enhanced stability and translation of CTNNB1 mRNA and promoting IRES-mediated protein synthesis, respectively. Eventually, the increased CTNNB1 protein levels mediated excessive activation of the Wnt/β-catenin signaling pathway and its downstream targets C-myc, COX-2, CCND1, MMP7, VEGFA and CD44.

CONCLUSION

Our results support CIRP as a candidate oncogene in NSCLC and a potential target for NSCLC therapy.

Short-term effects of cold spells on hospitalisations for acute exacerbation of chronic obstructive pulmonary disease: a time-series study in Beijing, China

OBJECTIVES

Our work aimed at exploring the relationship between cold spells and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) hospitalisations in Beijing, China, and assessing the moderating effects of the intensities and the durations of cold spells, as well as identifying the vulnerable.

DESIGN

A time-series study.

SETTING

We obtained time-series data of AECOPD hospitalisations, meteorological variables and air quality index in Beijing, China during 2012-2016.

PARTICIPANTS

All AECOPD hospitalisations among permanent residents in Beijing, China during the cold seasons (November-March) of 2012-2016 were included (n=84 571).

PRIMARY AND SECONDARY OUTCOME MEASURES

A quasi-Poisson regression with a distributed lag model was fitted to investigate the short-term effects of cold spells on AECOPD hospitalisations by comparing the counts of AECOPD admissions during cold spell days with those during non-cold spell days.

RESULTS

Cold spells under different definitions were associated with increased risk of AECOPD hospitalisations, with the maximum cumulative relative risk (CRR) over 3 weeks (lag0-21). The cumulative effects at lag0-21 increased with the intensities and the durations of cold spells. Under the optimal definition, the most significant single-day relative risk (RR) was found on the days of cold spells (lag0) with an RR of 1.042 (95% CI 1.013 to 1.072), and the CRR at lag0-21 was 1.394 (95% CI 1.193 to 1.630). The elderly (aged ≥65) were more vulnerable to the effects of cold spells on AECOPD hospitalisations.

CONCLUSION

Cold spells are associated with increased AECOPD hospitalisations in Beijing, with the cumulative effects increased with intensities and durations. The elderly are at particular risk of AECOPD hospitalisations triggered by cold spells.

Cold-inducible RNA-binding protein (CIRBP) promotes porcine reproductive and respiratory syndrome virus (PRRSV)-induced inflammatory response

Porcine reproductive and respiratory syndrome virus (PRRSV) infection causes severe systemic inflammation. Based on transcriptome sequencing data, a new cold-inducible RNA-binding protein (CIRBP) was identified, and its upregulated expression was detected in PRRSV-infected porcine alveolar macrophages (PAMs). However, the immunoregulatoryeffect of CIRBP in PRRSV infection remains unclear. In this study, we found that CIRBP, as an RNA-binging protein, migrates to the cytoplasm from the nucleus and exists in cytoplasmic stress granules under PRRSV infection. In addition, as a new pro-inflammatory factor, the overexpression of CIRBP promotes the expression of inflammatory cytokines and oxidative stress as showing the production of iNOS and ROS in PRRSV-infected cells, which contributes to the inflammatory response via the NF-κB pathway. Our findings suggested that CIRBP is involved in the regulation of PRRSV-induced inflammatory response.

Cold-Inducible RNA-Binding Protein Prevents an Excessive Heart Rate Response to Stress by Targeting Phosphodiesterase

RATIONALE

The stress response of heart rate, which is determined by the plasticity of the sinoatrial node (SAN), is essential for cardiac function and survival in mammals. As an RNA-binding protein, CIRP (cold-inducible RNA-binding protein) can act as a stress regulator. Previously, we have documented that CIRP regulates cardiac electrophysiology at posttranscriptional level, suggesting its role in SAN plasticity, especially upon stress conditions.

OBJECTIVE

Our aim was to clarify the role of CIRP in SAN plasticity and heart rate regulation under stress conditions.

METHODS AND RESULTS

Telemetric ECG monitoring demonstrated an excessive acceleration of heart rate under isoprenaline stimulation in conscious CIRP-KO (knockout) rats. Patch-clamp analysis and confocal microscopic Ca²⁺ imaging of isolated SAN cells demonstrated that isoprenaline stimulation induced a faster spontaneous firing rate in CIRP-KO SAN cells than that in WT (wild type) SAN cells. A higher concentration of cAMP-the key mediator of pacemaker activity-was detected in CIRP-KO SAN tissues than in WT SAN tissues. RNA sequencing and quantitative real-time polymerase chain reaction analyses of single cells revealed that the 4B and 4D subtypes of PDE (phosphodiesterase), which controls cAMP degradation, were significantly decreased in CIRP-KO SAN cells. A PDE4 inhibitor (rolipram) abolished the difference in beating rate resulting from CIRP deficiency. The mechanistic study showed that CIRP stabilized the mRNA of Pde4b and Pde4d by direct mRNA binding, thereby regulating the protein expression of PDE4B and PDE4D at posttranscriptional level.

CONCLUSIONS

CIRP acts as an mRNA stabilizer of specific PDEs to control the cAMP concentration in SAN, maintaining the appropriate heart rate stress response.

Cold-inducible RNA-binding protein (CIRP) induces translation of the cell-cycle inhibitor p27Kip1

The CDK inhibitor p27^Kip1 plays a central role in controlling cell proliferation and cell-cycle exit. p27^Kip1 protein levels oscillate during cell-cycle progression and are regulated by mitogen or anti-proliferative signaling. The abundance of the protein is frequently determined by post-transcriptional mechanisms including ubiquitin-mediated proteolysis and translational control. Here, we report that the cold-inducible RNA-binding protein (CIRP) selectively binds to the 5′ untranslated region of the p27^Kip1 mRNA. CIRP is induced, modified and relocalized in response to various stress stimuli and can regulate cell survival and cell proliferation particularly during stress. Binding of CIRP to the 5′UTR of the p27^Kip1 mRNA significantly enhanced reporter translation. In cells exposed to mild hypothermia, the induction of CIRP correlated with increased translation of a p27^Kip1 5′UTR reporter and with the accumulation of p27^Kip1 protein. shRNA-mediated CIRP knockdown could prevent the induction of translation. We found that p27^Kip1 is central for the decreased proliferation at lower temperature, since p27^Kip1 KO mouse embryonic fibroblasts (MEFs) hardly increased their doubling time in hypothermic conditions, whereas wild-type MEFs significantly delayed proliferation in response to cold stress. This suggests that the CIRP-dependent p27^Kip1 upregulation during mild hypothermia contributes to the cold shock-induced inhibition of cell proliferation.

CIRBP is a novel oncogene in human bladder cancer inducing expression of HIF-1α

Cold-inducible RNA binding protein (CIRBP) has been reported to be associated with distinct tumorigenesis. In this study, we investigated the role of CIRBP in human bladder cancer (BCa), indicating that CIRBP is overexpressed in BCa tissues and cell lines to promote proliferation and migration. Moreover, CIRBP could induce expression of HIF-1α via binding to the 3′-UTR of its mRNA to increase the mRNA stability in BCa cells. Furthermore, we demonstrated that PTGIS is a HIF-1α targeted gene, a major regulator in hypoxic cancer progression by activating transcription of various oncogenes. Our results also suggested that overexpression of HIF-1α may suppress the expression of PTGIS in BCa cells, by binding to HRE sequence at the promoter region of PTGIS. In addition, we found a strongly downregulation of PTGIS in BCa tissue and transcriptionally inhibited by HIF-1α in BCa cells, which could be triggered by its DNA methylation. Further result suggested that knockdown of CIRBP could promote the expression of PTGIS, meanwhile knockdown of PTGIS could partially rescue CIRBP-deficiency induced inhibition of migration and proliferation in BCa cells. Taken together, our study indicated that CIRBP could be a novel oncogene in human bladder cancer inducing transcription of HIF-1α, which could inhibit expression of methylated PTGIS.

Differential expression of RNA-binding proteins in bronchial epithelium of stable COPD patients

Purpose

Inflammatory gene expression is modulated by posttranscriptional regulation via RNA-binding proteins (RBPs), which regulate mRNA turnover and translation by binding to conserved mRNA sequences. Their role in COPD is only partially defined. This study evaluated RBPs tristetraprolin (TTP), human antigen R (HuR), and AU-rich element-binding factor 1 (AUF-1) expression using lung tissue from COPD patients and control subjects and probed their function in epithelial responses in vitro.

Patients and methods

RBPs were detected by immunohistochemistry in bronchial and peripheral lung samples from mild-to-moderate stable COPD patients and age/smoking history-matched controls; RBPs and RBP-regulated genes were evaluated by Western blot, ELISA, protein array, and real-time PCR in human airway epithelial BEAS-2B cell line stimulated with hydrogen peroxide, cytokine combination (cytomix), cigarette smoke extract (CSE), and following siRNA-mediated silencing. Results were verified in a microarray database from bronchial brushings of COPD patients and controls. RBP transcripts were measured in peripheral blood mononuclear cell samples from additional stable COPD patients and controls.

Results

Specific, primarily nuclear immunostaining for the RBPs was detected in structural and inflammatory cells in bronchial and lung tissues. Immunostaining for AUF-1, but not TTP or HuR, was significantly decreased in bronchial epithelium of COPD samples vs controls. In BEAS-2B cells, cytomix and CSE stimulation reproduced the RBP pattern while increasing expression of AUF-1-regulated genes, interleukin-6, CCL2, CXCL1, and CXCL8. Silencing expression of AUF-1 reproduced, but not enhanced, target upregulation induced by cytomix compared to controls. Analysis of bronchial brushing-derived transcriptomic confirmed the selective decrease of AUF-1 in COPD vs controls and revealed significant changes in AUF-1-regulated genes by genome ontology.

Conclusion

Downregulated AUF-1 may be pathogenic in stable COPD by altering posttranscriptional control of epithelial gene expression.

COPD rat model is more susceptible to cold stress and PM2.5 exposure and the underlying mechanism

The purpose of this study is to verify the hypothesis that chronic obstructive pulmonary disease (COPD) model rat is more susceptible to cold stress and fine particulate matter (PM_2.5) exposure than the healthy rat, and explore the related mechanism. COPD rat model, established with cigarette smoke and lipopolysaccharide intratracheal instillation, were exposed to cold stress (0 °C) and PM_2.5 (0, 3.2, 12.8 mg/ml). After that, the levels of superoxide dismutase, inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1) and angiotensin Ⅱ (Ang-Ⅱ) in lung were measured, as well as the expression levels of lung 8-hydroxy-2-deoxyguanosine (8-OHdG), nuclear factor kappa B (NF-κB), heme-oxygenase-1 (HO-1) and nuclear factor erythroid-2-related factor 2 (Nrf2). There were significant positive relationships between PM_2.5 and lung level of iNOS, TNF-α, MCP-1 and Ang-Ⅱ, lung function and pathologic damage in COPD rats. The HO-1, NF-κB and 8-OHdG were found highly expressed in COPD rat lung, particularly at the higher PM_2.5 dose of cold stress groups, while Nrf2 was found declined. Thus, COPD rats may be more susceptible to cold stress and PM_2.5 exposure. Cold stress may aggravate PM_2.5-induced toxic effects in the lung of COPD rats through increasing Ang-Ⅱ/NF-κB signaling pathway and suppressing Nrf2 signaling pathway.

Effects of Modified Zhisou Powder on Airway Mucus Production in Chronic Obstructive Pulmonary Disease Model Rats with Cold-Dryness Syndrome

Objective. In China, the Chinese medicine formula modified zhisou powder (MZP) is commonly used to treat COPD with cold-dryness syndrome (CDSCOPD) to relieve cough and sputum. However, the underlying mechanisms of MZP on treating CDSCOPD remain to be elucidated. Methods. COPD and CDSCOPD rat models were established; MZP was given to CDSCOPD rats in the last 7 days of the 97-day model establishment. Then the rats were subjected to lung function measurement. Pathological changes in lungs were observed through paraffin section and H&E staining. The mRNA and protein levels of AQP1, 4, and 5 and Muc5AC and Muc5B in lung were determined by quantitative RT-PCR and western blotting. NE levels was determined by ELISA. Results. The impaired lung functions were observed in rats exposed to cigarette smoke. Among all parameters evaluating lung functions, only tidal volume demonstrates a further decrease in CDSCOPD when compared with COPD, indicating further impaired pulmonary ventilation functions upon cold-dryness stimulation. The intervention of MZP effectively improved lung functions parameters, prevented the inflammations, and eliminated the increases of AQP4 and 5 and the decrease of Muc5AC in lung. Conclusion. MZP probably improves pulmonary functions in CDSCOPD through inhibiting lung inflammation, increasing expressions of AQPs, and decreasing Muc5AC expression in lung.

Cold-inducible RNA binding protein in cancer and inflammation

RNA binding proteins (RBPs) play key roles in RNA dynamics, including subcellular localization, translational efficiency and metabolism. Cold-inducible RNA binding protein (CIRP) is a stress-induced protein that was initially described as a DNA damage-induced transcript (A18 hnRNP), as well as a cold-shock domain containing cold-stress response protein (CIRBP) that alters the translational efficiency of its target messenger RNAs (mRNAs). This review summarizes recent work on the roles of CIRP in the context of inflammation and cancer. The function of CIRP in cancer appeared to be solely driven though its functions as an RBP that targeted cancer-associated mRNAs, but it is increasingly clear that CIRP also modulates inflammation. Several recent studies highlight roles for CIRP in immune responses, ranging from sepsis to wound healing and tumor-promoting inflammation. While modulating inflammation is an established role for RBPs that target cytokine mRNAs, CIRP appears to modulate inflammation by several different mechanisms. CIRP has been found in serum, where it binds the TLR4-MD2 complex, acting as a Damage-associated molecular pattern (DAMP). CIRP activates the NF-κB pathway, increasing phosphorylation of Iκκ and IκBα, and stabilizes mRNAs encoding pro-inflammatory cytokines. While CIRP promotes higher levels of pro-inflammatory cytokines in certain cancers, it also decreases inflammation to accelerate wound healing. This dichotomy suggests that the influence of CIRP on inflammation is context dependent and highlights the importance of detailing the mechanisms by which CIRP modulates inflammation. WIREs RNA 2018, 9:e1462. doi: 10.1002/wrna.1462 This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

Increased admission serum cold-inducible RNA-binding protein concentration is associated with prognosis of severe acute pancreatitis

BACKGROUND

Cold-inducible RNA-binding protein (CIRP) is a pro-inflammatory cytokine. This study assessed its relation to disease severity and major adverse events (namely local complications, organ failure and in-hospital mortality) of severe acute pancreatitis (SAP) and its discriminatory ability for SAP.

METHODS

This prospective and observational study recruited a total of 102 SAP patients, 48 patients with mild acute pancreatitis and 102 healthy individuals. Serum CIRP concentrations were determined using enzyme-linked immunosorbent assay.

RESULTS

Serum CIRP concentrations were significantly higher in patients compared to controls. Serum CIRP concentrations were highly correlated with the circulating concentrations of common inflammatory mediators (i.e., procalcitonin, C-reactive protein and white blood cell) and the traditional predictors of disease severity (namely Acute Physiology and Chronic Health Care Evaluation II score, Ranson score, multiple organ dysfunction score and sequential organ failure assessment score). CIRP in serum was an independent predictor for major adverse events. Serum CIRP concentrations showed high predictive value for major adverse events, and possessed high discriminatory performance for SAP. Moreover, its effects significantly exceeded those of the preceding inflammatory mediators.

CONCLUSIONS

Increased serum CIRP concentrations clearly reflect SAP severity and prognosis and significantly distinguish SAP, substantializing CIRP as a potential SAP biomarker.