An increasing number of studies have demonstrated that the dysregulation of long non-coding RNAs (lncRNAs) may serve an important role in tumor progression. Previous studies have reported that the lncRNA, colon cancer associated transcript 2 (CCAT2), was highly expressed in various tumors. However, the function of CCAT2 in hepatocellular carcinoma (HCC) has not yet been elucidated. The aim of the present study was to identify novel oncogene lncRNAs and investigate their physiological function and mechanism in HCC. Using reverse transcription-quantitative polymerase chain reaction, it was observed that CCAT2 was upregulated in HCC tissues and human HCC cell lines. Furthermore, the impacts of CCAT2 on cell proliferation, migration and apoptosis were analyzed using cell migration, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and enzyme-linked immunosorbent assay analysis respectively. The overexpression of CCAT2 using a synthesized vector significantly promoted cell migration and proliferation, and inhibited apoptosis of HCC cells in vitro. The suppression of CCAT2 expression resulted in opposing effects. To the best of our knowledge, the present study is the first to demonstrate that CCAT2 functions as a oncogene in HCC. Further investigation is required to clarify the molecular mechanisms of this lncRNA in HCC development.

Bioartificial livers may act as a promising therapy for fulminant hepatic failure (FHF) with better accessibility and less injury compared to orthotopic liver transplantation. This study aims to evaluate the efficacy and safety of a fluidized bed bioartificial liver (FBBAL) and to explore its therapeutic mechanisms based on metabolomics. FHF was induced by D-galactosamine. Eighteen hours later, pigs were treated with an FBBAL containing encapsulated primary porcine hepatocytes (B group), with a sham FBBAL (containing cell-free capsules, S group) or with only intensive care (C group) for 6 h. Serum samples were assayed using ultra-performance liquid chromatography-mass spectrometry. The difference in survival time (51.6 ± 7.9 h vs. 49.3 ± 6.6 h) and serum metabolome was negligible between the S and C groups, whereas FBBAL treatment significantly prolonged survival time (70.4 ± 11.5h, P < 0.01) and perturbed the serum metabolome, resulting in a marked decrease in phosphatidylcholines, lysophosphatidylcholines, sphingomyelinase, and fatty acids and an increase in conjugated bile acids. The FBBAL exhibits some liver functions and may exert its therapeutic effect by altering the serum metabolome of FHF pigs. Moreover, alginate-chitosan capsules have less influence on serum metabolites. Nevertheless, the alterations were not universally beneficial, revealing that much should be done to improve the FBBAL.

Stem cell therapy has a potential for regenerating damaged myocardium. However, a key obstacle to cell therapy's success is the loss of engrafted cells due to apoptosis or necrosis in the ischemic myocardium. While many strategies have been developed to improve engrafted cell survival, tools to evaluate cell efficacy within the body are limited. Traditional genetic labeling tools, such as GFP-like fluorescent proteins (eGFP, DsRed, mCherry), have limited penetration depths in vivo due to tissue scattering and absorption. To circumvent these limitations, a near-infrared fluorescent mutant of the DrBphP bacteriophytochrome from Deinococcus radiodurans, IFP1.4, was developed for in vivo imaging, but it has yet to be used for in vivo stem/progenitor cell tracking. In this study, we incorporated IFP1.4 into mouse cardiac progenitor cells (CPCs) by a lentiviral vector. Live IFP1.4-labeled CPCs were imaged by their near-infrared fluorescence (NIRF) using an Odyssey scanner following overnight incubation with biliverdin. A significant linear correlation was observed between the amount of cells and NIRF signal intensity in in vitro studies. Lentiviral mediated IFP1.4 gene labeling is stable, and does not impact the apoptosis and cardiac differentiation of CPC. To assess efficacy of our model for engrafted cells in vivo, IFP1.4-labeled CPCs were intramyocardially injected into infarcted hearts. NIRF signals were collected at 1-day, 7-days, and 14-days post-injection using the Kodak in vivo multispectral imaging system. Strong NIRF signals from engrafted cells were imaged 1 day after injection. At 1 week after injection, 70% of the NIRF signal was lost when compared to the intensity of the day 1 signal. The data collected 2 weeks following transplantation showed an 88% decrease when compared to day 1. Our studies have shown that IFP1.4 gene labeling can be used to track the viability of transplanted cells in vivo.

Two-photon laser scanning microscopy has revolutionized the ability to delineate cellular and physiological function in acutely isolated tissue and in vivo. However, there exist barriers for many laboratories to acquire two-photon microscopes. Additionally, if owned, typical systems are difficult to modify to rapidly evolving methodologies. A potential solution to these problems is to enable scientists to build their own high-performance and adaptable system by overcoming a resource insufficiency. Here we present a detailed hardware resource and protocol for building an upright, highly modular and adaptable two-photon laser scanning fluorescence microscope that can be used for in vitro or in vivo applications. The microscope is comprised of high-end componentry on a skeleton of off-the-shelf compatible opto-mechanical parts. The dedicated design enabled imaging depths close to 1 mm into mouse brain tissue and a signal-to-noise ratio that exceeded all commercial two-photon systems tested. In addition to a detailed parts list, instructions for assembly, testing and troubleshooting, our plan includes complete three dimensional computer models that greatly reduce the knowledge base required for the non-expert user. This open-source resource lowers barriers in order to equip more laboratories with high-performance two-photon imaging and to help progress our understanding of the cellular and physiological function of living systems.

β2-adrenoceptor agonists are commonly used as bronchodilators to treat obstructive lung diseases such as asthma and chronic obstructive pulmonary disease (COPD), however, they induce severe side effects. Therefore, developing new bronchodilators is essential. Herbal plants were extracted and the extracts' effect on airway smooth muscle (ASM) precontraction was assessed. The ethyl alcohol extract of semen cassiae (EESC) was extracted from Semen cassia. The effects of EESC on the ACh- and 80 mM K+-induced sustained precontraction in mouse and human ASM were evaluated. Ca2+ permeant ion channel currents and intracellular Ca2+ concentration were measured. HPLC analysis was employed to determine which compound was responsible for the EESC-induced relaxation. The EESC reversibly inhibited the ACh- and 80 mM K+-induced precontraction. The sustained precontraction depends on Ca2+ influx, and it was mediated by voltage-dependent L-type Ca2+ channels (LVDCCs), store-operated channels (SOCs), TRPC3/STIM/Orai channels. These channels were inhibited by aurantio-obtusin, one component of EESC. When aurantio-obtusin removed, EESC's action disappeared. In addition, aurantio-obtusin inhibited the precontraction of mouse and human ASM and intracellular Ca2+ increases. These results indicate that Semen cassia-contained aurantio-obtusin inhibits sustained precontraction of ASM via inhibiting Ca2+-permeant ion channels, thereby, which could be used to develop new bronchodilators.

BACKGROUND Ubiquilin-4 (UBQLN4) is a component of the ubiquitin-proteasome system and regulates the degradation of many proteins implicated in pathological conditions. The aim of this study was to determine the role of UBQLN4 in regulating the proliferation and survival of the normal gastric epithelial cell line GES-1. MATERIAL AND METHODS We constructed GES-1 lines stably overexpressing UBQLN4 by lentiviral infection. Cell proliferation, apoptosis, and the cell cycle were analyzed using the MTT assay and flow cytometric assays. Phosphorylation of ERK, JNK, p38, and expression of cyclin D1 were detected by western blot analysis. RESULTS Overexpression of UBQLN4 significantly reduced proliferation and induced G2/M phase arrest and apoptosis in GES-1 cells. Moreover, upregulation of UBQLN4 increased the expression of cyclin D1 and phosphorylated ERK, but not JNK or p38. CONCLUSIONS These data suggest that UBQLN4 may induce cell cycle arrest and apoptosis via activation of the ERK pathway and upregulation of cyclin D1 in GES-1 cells.

BACKGROUND In recent years, the incidence of gastric cancer (GC) has been increasing worldwide. Emerging evidence shows that microRNAs (miRs) may be involved in the pathogenesis of GC. Thus, this study explored the mediatory role of miR-495 in GC chemosensitivity, and investigated the mechanism by which it affects the biological behaviors of GC cells via the mTOR signaling pathway. MATERIAL AND METHODS After GC and paracancerous tissue collection, the positive rate of ERBB2 and mTOR was evaluated by immunohistochemistry. Subsequently, the expression of miR-495, ERBB2, and mTOR was determined by RT-qPCR and Western blot analysis. Next, the targeting relationship between miR-495 and ERBB2 was confirmed by dual-luciferase reporter gene assay. In addition, chemosensitivity and proliferation were detected by MTT assay and apoptosis was assessed by flow cytometry. RESULTS We found higher positive rates of ERBB2 and mTOR and decreased expression of miR-495 in GC tissues and showed that ERBB2 is the target gene of miR-495. Furthermore, we determined that overexpression of miR-495 and silencing of ERBB2 enhanced GC cell chemosensitivity and apoptosis, but inhibited GC cell proliferation. We also found that the effect of miR-495 inhibition was lost when ERBB2 was suppressed. CONCLUSIONS The key findings of our study demonstrate that the miR-495 exerts promotive effects on GC chemosensitivity via inactivation of the mTOR signaling pathway by suppressing ERBB2. The study provides reliable evidence supporting the use of miR-495 as a novel potential target in the chemotherapy of GC.

Cardiac hypertrophy after myocardial infarction (MI) is an independent risk factor for heart failure. Regression of cardiac hypertrophy has emerged as a promising strategy in the treatment of MI patients. Here, we have been suggested that heat-shock transcription factor 1 (HSF1) is a novel repressor of ischaemia-induced cardiac hypertrophy. Ligation of left anterior descending coronary was used to produce MI in HSF1-deficient heterozygote (KO), HSF1 transgenic (TG) mice and their wild-type (WT) littermates, respectively. Neonatal rat cardiomyocytes (NRCMs) were treated by hypoxia to mimic MI in vitro. The HSF1 phosphorylation was significantly reduced in the infarct border zone of mouse left ventricles (LVs) 1 week after MI and in the hypoxia-treated NRCMs. HSF1 KO mice showed more significant maladaptive cardiac hypertrophy and deteriorated cardiac dysfunction 1 week after MI compared to WT MI mice. Deficiency of HSF1 by siRNA transfection notably increased the hypoxia-induced myocardial hypertrophy in NRCMs. Mechanistically, Janus kinase 2 (JAK2) and its effector, signal transducer and activator of transcription 3 (STAT3) were found to be significantly increased in the LV infarct border zone of WT mice after MI as well as the NRCMs treated by hypoxia. These alterations were more significant in HSF1 KO mice and NRCMs transfected with HSF1 SiRNA. Inversely, HSF1 TG mice showed significantly ameliorated cardiac hypertrophy and heart failure 1 week after LAD ligation compared to their WT littermates. Our data collectively demonstrated that HSF1 is critically involved in the pathological cardiac hypertrophy after MI via modulating JAK2/STAT3 signalling and may constitute a potential therapeutic target for MI patients.

Allergic asthma is a lifelong airway condition that affects people of all ages. In recent decades, asthma prevalence continues to increase globally, with an estimated number of 250,000 annual deaths attributed to the disease. Although inhaled corticosteroids and β-adrenergic receptor agonists are the primary therapeutic avenues that effectively reduce asthma symptoms, profound side effects may occur in patients with long-term treatments. Therefore, development of new therapeutic strategies is needed as alternative or supplement to current asthma treatments. Sesamin is a natural polyphenolic compound with strong anti-oxidative effects. Several studies have reported that sesamin is effective in preventing hypertension, thrombotic tendency, and neuroinflammation. However, it is still unknown whether sesamin can reduce asthma-induced allergic inflammation and airway hyperresponsiveness (AHR). Our study has revealed that sesamin exhibited significant anti-inflammatory effects in ovalbumin (OVA)-induced murine asthma model. We found that treatments with sesamin after OVA sensitization and challenge significantly decreased expression levels of interleukin-4 (IL-4), IL-5, IL-13, and serum IgE. The numbers of total inflammatory cells and eosinophils in BALF were also reduced in the sesamin-treated animals. Histological results demonstrated that sesamin attenuated OVA-induced eosinophil infiltration, airway goblet cell hyperplasia, mucus occlusion, and MUC5AC expression in the lung tissue. Mice administered with sesamin showed limited increases in AHR compared with mice receiving vehicle after OVA challenge. OVA increased phosphorylation levels of IκB-α and nuclear expression levels of NF-κB, both of which were reversed by sesamin treatments. These data indicate that sesamin is effective in treating allergic asthma responses induced by OVA in mice.

Near-infrared fluorescence (NIRF) imaging by using infrared fluorescent protein (iRFP) gene labelling is a novel technology with potential value for in vivo applications. In this study, we expressed iRFP in mouse cardiac progenitor cells (CPC) by lentiviral vector and demonstrated that the iRFP-labelled CPC (CPC(iRFP)) can be detected by flow cytometry and fluorescent microscopy. We observed a linear correlation in vitro between cell numbers and infrared signal intensity by using the multiSpectral imaging system. CPC(iRFP) injected into the non-ischaemic mouse hindlimb were also readily detected by whole-animal NIRF imaging. We then compared iRFP against green fluorescent protein (GFP) for tracking survival of engrafted CPC in mouse ischaemic heart tissue. GFP-labelled CPC (CPC(GFP)) or CPC labelled with both iRFP and GFP (CPC(iRFP) (GFP)) were injected intramyocardially into mouse hearts after infarction. Three days after cell transplantation, a strong NIRF signal was detected in hearts into which CPC(iRFP) (GFP), but not CPC(GFP), were transplanted. Furthermore, iRFP fluorescence from engrafted CPC(iRFP) (GFP) was detected in tissue sections by confocal microscopy. In conclusion, the iRFP-labelling system provides a valuable molecular imaging tool to track the fate of transplanted progenitor cells in vivo.

Insulin inhibits ischemia/reperfusion-induced myocardial apoptosis through the activation of a survival signaling cascade including the phosphatidylinositol 3-kinase (PI3K)-Akt pathway. However, the down-stream mechanism of PI3K remains elusive. This study is aimed at investigating whether survivin (SVV) plays a role in the insulin-induced anti-apoptotic effect in the ischemic/reperfused (I/R) hearts, and if so, further determining the signaling mechanism involved. Isolated adult rat hearts were subjected to 30 min regional ischemia followed by reperfusion with or without insulin (10(-7)mol/L) at the onset of reperfusion. Reperfusion with insulin inhibited myocardial apoptosis and reduced infarct size, along with significantly up-regulated myocardial SVV expression (5.9±0.3 Group MI/R+Ins vs. 2.1±0.1 Group MI/R, p<0.05) and increased phosphorylations of mTOR and p70S6K compared with I/R group, which was blocked by pretreatment of PI3K inhibitor LY294002. Rapamycin, a specific mTOR inhibitor, did not alter insulin-induced Akt phosphorylation but significantly inhibited SVV expression (from 6.1±0.3 to 3.0±0.15, p<0.05). Moreover, rapamycin blunted insulin-induced anti-apoptosis in the I/R hearts (8.1±0.4% vs. 16.5±1.8%, p<0.05). To further ascertain the role of SVV in insulin-induced cardioprotection, cardiomyocytes were transfected with adenovirus encoding SVV (gain-of-function) or siRNA targeting SVV (loss-of-function). Overexpression of SVV decreased I/R-induced cardiomyocyte apoptosis in vitro, while siRNA targeting SVV significantly blunted the anti-apoptotic effect of insulin. Taken together, these results suggest a novel role of PI3K/Akt/mTOR/SVV signaling in the cardioprotective effect of insulin.

Optimal timing of cell therapy for myocardial infarction (MI) appears during 5 to 14 days after the infarction. However, the potential mechanism requires further investigation. This work aimed to verify the hypothesis that myocardial stiffness within a propitious time frame might provide a most beneficial physical condition for cell lineage specification in favour of cardiac repair. Serum vascular endothelial growth factor (VEGF) levels and myocardial stiffness of MI mice were consecutively detected. Isolated bone marrow mononuclear cells (BMMNCs) were injected into infarction zone at distinct time-points and cardiac function were measured 2 months after infarction. Polyacrylamide gel substrates with varied stiffness were used to mechanically mimic the infarcted myocardium. BMMNCs were plated on the flexible culture substrates under different concentrations of VEGF. Endothelial progenitor lineage commitment of BMMNCs was verified by immunofluorescent technique and flow cytometry. Our results demonstrated that the optimal timing in terms of improvement of cardiac function occurred during 7 to 14 days after MI, which was consistent with maximized capillary density at this time domains, but not with peak VEGF concentration. Percentage of double-positive cells for DiI-labelled acetylated low-density lipoprotein uptake and fluorescein isothiocyanate (FITC)-UEA-1 (ulex europaeus agglutinin I lectin) binding had no significant differences among the tissue-like stiffness in high concentration VEGF. With the decrease of VEGF concentration, the benefit of 42 kPa stiffness, corresponding to infarcted myocardium at days 7 to 14, gradually occurred and peaked when it was removed from culture medium. Likewise, combined expressions of VEGFR2(+) , CD133(+) and CD45(-) remained the highest level on 42 kPa substrate in conditions of lower concentration VEGF. In conclusion, the optimal efficacy of BMMNCs therapy at 7 to 14 days after MI might result from non-VEGF dependent angiogenesis, and myocardial stiffness at this time domains was more suitable for endothelial progenitor lineage specification of BMMNCs. The results here highlight the need for greater attention to mechanical microenvironments in cell culture and cell therapy.

Because of the serious side effects of the currently used bronchodilators, new compounds with similar functions must be developed. We screened several herbs and found that Polygonum aviculare L. contains ingredients that inhibit the precontraction of mouse and human airway smooth muscle (ASM). High K+-induced precontraction in ASM was completely inhibited by nifedipine, a selective blocker of L-type voltage-dependent Ca2+ channels (LVDCCs). However, nifedipine only partially reduced the precontraction induced by acetylcholine chloride (ACH). Additionally, the ACH-induced precontraction was partly reduced by pyrazole-3 (Pyr3), a selective blocker of TRPC3 and stromal interaction molecule (STIM)/Orai channels. These channel-mediated currents were inhibited by the compounds present in P. aviculare extracts, suggesting that this inhibition was mediated by LVDCCs, TRPC3 and/or STIM/Orai channels. Moreover, these channel-mediated currents were inhibited by quercetin, which is present in P. aviculare extracts. Furthermore, quercetin inhibited ACH-induced precontraction in ASM. Overall, our data indicate that the ethyl acetate fraction of P. aviculare and quercetin can inhibit Ca2+-permeant LVDCCs, TRPC3 and STIM/Orai channels, which inhibits the precontraction of ASM. These findings suggest that P. aviculare could be used to develop new bronchodilators to treat obstructive lung diseases such as asthma and chronic obstructive pulmonary disease.

The aim of this study was to explore the estrogenic effects of the extracts from Chinese yam and its effective compounds.

The valosin-containing protein (VCP) participates in signaling pathways essential for cell homeostasis in multiple tissues, however, its function in the heart in vivo remains unknown. Here we offer the first description of the expression, function and mechanism of action of VCP in the mammalian heart in vivo in both normal and stress conditions. By using a transgenic (TG) mouse with cardiac-specific overexpression (3.5-fold) of VCP, we demonstrate that VCP is a new and powerful mediator of cardiac protection against cell death in vivo, as evidenced by a 50% reduction of infarct size after ischemia/reperfusion versus wild type. We also identify a novel role of VCP in preserving mitochondrial respiration and in preventing the opening of mitochondrial permeability transition pore in cardiac myocytes under stress. In particular, by genetic deletion of inducible isoform of nitric oxide synthase (iNOS) from VCP TG mouse and by pharmacological inhibition of iNOS in isolated cardiac myocytes, we reveal that an increase of expression and activity of iNOS in cardiomyocytes by VCP is an essential mechanistic link of VCP-mediated preservation of mitochondrial function. These data together demonstrate that VCP may represent a novel therapeutic avenue for the prevention of myocardial ischemia.

Rationale: Cell therapy for myocardial infarction is promising but largely unsuccessful in part due to a lack of mechanistic understanding. Techniques enabling identification of stem cell-specific proteomes in situ in the injured heart may shed light on how the administered cells respond to the injured microenvironment and exert reparative effects. Objective: To identify the proteomes of the transplanted mesenchymal stem cells (MSCs) in the infarcted myocardium, we sought to target a mutant methionyl-tRNA synthetase (MetRSL274G) in MSCs, which charges azidonorleucine (ANL), a methionine analogue and non-canonical amino acid, to tRNA and subsequently to nascent proteins, permitting isolation of ANL-labeled MSC proteomes from ischemic hearts by ANL-alkyne based click reaction. Methods and Results: Murine MSCs were transduced with lentivirus MetRSL274G and supplemented with ANL; the ANL-tagged nascent proteins were visualized by bio-orthogonal non-canonical amino-acid tagging, spanning all molecular weights and by fluorescent non-canonical amino-acid tagging, displaying strong fluorescent signal. Then, the MetRSL274G-transduced MSCs were administered to the infarcted or Sham heart in mice receiving ANL treatment. The MSC proteomes were isolated from the left ventricular protein lysates by click reaction at days 1, 3, and 7 after cell administration, identified by LC/MS. Among all identified proteins (in Sham and MI hearts, three time-points each), 648 were shared by all 6 groups, accounting for 82±5% of total proteins in each group, and enriched under mitochondrion, extracellular exosomes, oxidation-reduction process and poly(A) RNA binding. Notably, 26, 110 and 65 proteins were significantly up-regulated and 11, 28 and 19 proteins were down-regulated in the infarcted vs. Sham heart at the three time-points, respectively; these proteins are pronounced in the GO terms of extracellular matrix organization, response to stress and regulation of apoptotic process and in the KEGG pathways of complements and coagulation cascades, apoptosis, and regulators of actin cytoskeleton. Conclusions: MetRSL274G expression allows successful identification of MSC-specific nascent proteins in the infarcted hearts, which reflect the functional states, adaptive response, and reparative effects of MSCs that may be leveraged to improve cardiac repair.

In cochlear implants, pulse amplitude (PA) or pulse phase duration (PPD) can be used to increase loudness. Loudness grows more slowly with increasing PPD, resulting in a larger dynamic range (DR), possibly reflecting "leaky" charge integration associated with neural degeneration due to hearing loss. Here, we propose a method to estimate charge integration efficiency for CI users.

In Tianjin, China, there is a relatively high prevalence of HIV in men who have sex with men (MSM). The number of HIV cases in Tianjin is also increasing. We investigated the HIV molecular transmission network, genetic tropisms, and drug resistance mutations in Tianjin.

Latest clinical research shows that trimetazidine therapy during the perioperative period relieves endothelial dysfunction in patients with unstable angina induced by percutaneous coronary intervention. In this study we investigated the effects of TMZ on myocardial angiogenesis in pressure overload-induced cardiac hypertrophy mice. Cardiac hypertrophy was induced in mice by transverse aortic constriction (TAC) surgery. TAC mice were administered trimetazidine (2.8 mg/100 µL, i.g.) for 28 consecutive days. We showed that trimetazidine administration significantly increased blood vessel density in the left ventricular myocardium and abrogated cardiac dysfunction in TAC mice. Co-administration of a specific HSF1 inhibitor KRIBB11 (1.25 mg/100 µL, i.h.) abrogated the angiogenesis-promoting effects of trimetazidine in TAC mice. Using luciferase reporter and electrophoretic mobility shift assays we demonstrated that the transcription factor HSF1 bound to the promoter region of VEGF-A, and the transcriptional activity of HSF1 was enhanced upon trimetazidine treatment. In molecular docking analysis we found that trimetazidine directly bound to Akt via a hydrogen bond with Asp292 and a pi-pi bond with Trp80. In norepinephrine-treated HUVECs, we showed that trimetazidine significantly increased the phosphorylation of Akt and the synergistic nuclear translocation of Akt and HSF1, as well as the binding of Akt and HSF1 in the nucleus. These results suggest that trimetazidine enhances myocardial angiogenesis through a direct interaction with Akt and promotion of nuclear translocation of HSF1, and that trimetazidine may be used for the treatment of myocardial angiogenic disorders in hypertensive patients.

Circulation of influenza A virus (IAV), especially within poultry and pigs, continues to threaten public health. A simple and universal detecting method is important for monitoring IAV infection in different species. Recently, nanobodies, which show advantages of easy gene editing and low cost of production, are a promising novel diagnostic tool for the monitoring and control of global IAVs. In the present study, five nanobodies against the nucleoprotein of H9N2 IAV were screened from the immunized Bactrian camel by phage display and modified with horseradish peroxidase (HRP) tags. Out of which, we determined that H9N2-NP-Nb5-HRP can crossreact with different subtypes of IAVs, and this reaction is also blocked by positive sera for antibodies against different IAV subtypes. Epitope mapping showed that the nanobody-HRP fusion recognized a conserved conformational epitope in all subtypes of IAVs. Subsequently, we developed a nanobody-based competitive ELISA (cELISA) for detecting anti-IAV antibodies in different species. The optimized amount of coating antigen and dilutions of the fusion and testing sera were 100 ng/well, 1:4000, and 1:10, respectively. The time for operating the cELISA was approximately 35 min. The cELISA showed high sensitivity, specificity, reproducibility, and stability. In addition, we found that the cELISA and hemagglutination inhibition test showed a consistency of 100% and 87.91% for clinical and challenged chicken sera, respectively. Furthermore, the agreement rates were 90.4% and 85.7% between the cELISA and commercial IEDXX ELISA kit. Collectively, our developed nanobody-HRP fusion-based cELISA is an ideal method for monitoring IAV infection in different species.