Differentiating between micronucleus dose-responses induced by whole cigarette smoke solutions with Benchmark Dose potency ranking

Dose-response modeling of in vitro micronucleus test (IVMNT) data was evaluated to determine if the approach has value in discriminating among different tobacco products. Micronucleus responses were generated in L5178Y/Tk+/- mouse lymphoma cells and TK6 human lymphoblastoid cells from a series of whole smoke solutions (WSSs) expected to have different levels of genotoxicity based on differences in their machine-generated smoke constituents. Eight WSSs were prepared by machine smoking different numbers (20 or 60) of two commercial cigarettes (Marlboro Silver or Red) under International Standardization Organization (ISO) or Health Canada Intense (HCI) smoking machine regimens and tested in the two cell lines with and without rat liver S9 activation. The S9-mediated IVMNT dose-response data from the WSSs were evaluated with PROAST software and Benchmark Doses (BMDs) and their upper and lower confidence intervals (CIs) were generated. IVMNT data differed based on the number and type of cigarettes smoked and smoking machine regimen. The IVMNT responses produced in mouse lymphoma cells generally were greater than in TK6 cells, but the ability of the two cell types to differentiate between WSSs was similar. The results indicate that BMD potency ranking was useful for differentiating between IVMNT responses.

POS0369 ELEVATED EXPRESSION OF TIM-3 ON NEUTROPHILS CORRELATES WITH DISEASE ACTIVITY AND SEVERITY OF ANKYLOSING SPONDYLITIS

Background:

Ankylosing spondylitis (AS) is a type of common, chronic inflammatory disease that compromises the axial skeleton and sacroiliac joints, causing inflammatory low back pain and progressive spinal stiffness, over time some patients develop spinal immobility and ankylosis which can lead to a decrease in quality of life. The last few decades, evidence has clearly indicated that neutrophil also plays key roles in the progression of AS. However, the immunomodulatory roles and mechanisms of neutrophils in AS are poorly understood. T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) has been reported as an important regulatory molecule, expressed and regulated on different innate immune cells, plays a pivotal role in several autoimmunity diseases. Recent study indicates that Tim3 is also expressed on neutrophils. However, the frequency and roles of Tim3-expressing neutrophils in AS was not clear.

Objectives:

In this study, we investigated the expression of Tim3 on neutrophils in AS patients and explored the correlation between the level of Tim3-expressing neutrophils and the disease activity and severity of AS.

Methods:

Patients with AS were recruited from Guangdong Second Provincial General Hospital (n=62). Age/sex-matched volunteers as Healthy controls (HC) (n=39). The medical history, clinical manifestations, physical examination, laboratory measurements were recorded. The expression of costimulatory molecules including programmed death 1 (PD-1), Tim-3 on neutrophils were determined by flow cytometry. The mRNA expression of PD-1 and Tim-3 was determined by real-time PCR. The levels of Tim3-expressing neutrophils in AS patients were further analyzed for their correlation with the markers of inflammation such as ESR,CRP,WBC and neutrophil count(NE), as well as disease activity and severity of AS. The expression of Tim3 on neutrophils was monitored during the course of treatment (4 weeks).

Results:

The expression of Tim3 on neutrophils in patients with AS was increased compared to the HC (Figure 1A). However, significant difference was observed in the frequency of PD-1-expressing neutrophils between AS patients and HC (Figure 1B). The expression analysis of Tim-3 mRNA, but not PD-1, confirmed the results obtained from flow cytometry (Figure 1C). The level of Tim3-expressing neutrophils in patients with AS showed an positive correlation with ESR, CRP and ASAS-endorsed disease activity score (ASDAS) (Figure 1D). Moreover, the frequency of Tim3-expressing neutrophils in active patients(ASDAS≥1.3) was increased as compare with the inactive patients (ASDAS<1.3) (Figure 1E). As shown in Figure 1F, the frequency of Tim3-expressing neutrophils decreased after the treatment.

Conclusion:

Increased Tim-3 expression on neutrophils may be a novel indicator to assess disease activity and severity in AS, which may serves as a negative feedback mechanism preventing potential tissue damage caused by excessive inflammatory responses in AS patients.

References:

[1]Han, G., Chen, G., Shen, B. & Li, Y., Tim-3: an activation marker and activation limiter of innate immune cells. FRONT IMMUNOL 4 449 (2013).

[2]Vega-Carrascal, I. et al., Galectin-9 signaling through TIM-3 is involved in neutrophil-mediated Gram-negative bacterial killing: an effect abrogated within the cystic fibrosis lung. J IMMUNOL 192 2418 (2014).

Figure 1.

(A,B)The expression of Tim3 and PD-1 on neutrophils in AS and HC were determined by flow cytometry.(C) The expression of Tim3 and PD-1 on neutrophils in AS and HC were determined by RT-PCR.(D)The correction between Tim3-expressing neutrophils and ESR,CRP,ASDAS.(E) The expression of Tim3 on neutrophils in active and inactive patients.(F) Influence of treatment on the frequency of Tim3-expressing neutrophils.

Disclosure of Interests:

None declared

Identification of a mitogen-activated protein kinase kinase (AccMKK4) from Apis cerana cerana and its involvement in various stress responses

The mitogen-activated protein kinase (MAPK) cascade pathway is a ubiquitous signal transduction pathway in eukaryotes that regulates a variety of immune responses. This study accomplished the first isolation of an AccMKK4 gene from Apis cerana cerana and explored its function. Yeast two-hybrid experiments proved that AccMKK4 can interact with Accp38b, and the silencing of AccMKK4 in honeybees downregulated the expression level of Accp38b, which suggests that AccMKK4 might participate in the oxidative stress response through the p38 MAPK pathway. Tissue-specific expression levels of AccMKK4 analysis showed that AccMKK4 in the thorax, particularly muscle tissue, was higher than that in other tissues. The qRT-PCR results from different conditions demonstrated that AccMKK4 responds to various environmental stresses. After AccMKK4 silencing, the transcription level of some antioxidant genes and the activity of antioxidant-related enzymes are reduced, which indicated that AccMKK4 plays an important role in resistance against oxidative stress caused by external stimuli. In summary, our findings indicate that AccMKK4 probably plays an indispensable role in the response of honeybees to environmental stress and might aid for further research on the role of the MAPK cascade pathway in the antioxidant defence mechanisms of insects.

AB0066 MECHANISMS OF TOTAL SAPONINS OF PANAX JAPONICUS MITIGATES COLLAGEN-INDUCED ARTHRITIS

Background:

Total saponins of Panax japonicus (TSPJ) are extracted from Panax japonicus (T.Nees) C.A.Mey and have achieved a good therapeutic effect in the treatment of rheumatoid arthritis (RA). Unfortunately, the mechanism of TSPJ acting on RA is not clear.

Objectives:

To investigate the potential mechanisms and key targets of TSPJ on RA.

Methods:

The raw data were downloaded from the Gene Expression Omnibus (GEO) database, and the RStudio3.6.1 software was used to identify differentially expressed genes (DEGs). The potential targets of active compounds from TSPJ were predicted by the Pharmmapper and SwissTargetPrediction databases. Based on the overlapping genes, we used Cytoscape 3.7.2 software to construct a protein-protein interactions (PPI) network and to determine the mechanisms of the treatment by Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Collagen-induced arthritis (CIA) model was established and treated with different doses of TSPJ. Arthritis index (AI) and histology score were used to evaluate the symptoms of CIA. The levels of vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1 (HIF-1), IL-1β, and IL-17A tested by enzyme linked immunosorbent assay and real time-quantitative Polymerase Chain Reaction.

Results:

A total of 2670 DEGs and 371 TSPJ targets were obtained, including 52 overlapping genes. 41 genes had protein interactions that are used to build the PPI network. The results of the KEGG enrichment analysis included VEGF and HIF-1 signaling pathway. Seven negative correlation genes and 16 positive correlation genes were obtained by correlational analysis of DEGs in VEGF and HIF-1 signaling pathway. SRC proto-oncogene, nonreceptor tyrosine kinase (SRC), and the signal transducer and the activator of transcription 3 (STAT 3) had a higher value of degree in PPI and showed a significant correlation in the pathways; they were regarded as key targets. Compared with the CIA model group, TSPJ significantly decreased the AI and histology scores. Moreover, the expression of VEGF-A, HIF-1α, IL-1β, and IL-17A in serum or spleens significantly reduced in a dose-dependent.

Conclusion:

Present study show that SRC and STAT 3 may be the key targets of TSPJ acting on the VEGF and HIF-1 signaling pathways, thus inhibiting angiogenesis and improving RA.

Disclosure of Interests:

None declared

Inflammatory response or oxidative stress induces upregulation of PTPN2 and thus promotes the progression of laryngocarcinoma

OBJECTIVE

This study aims to investigate whether inflammatory response or oxidative stress could induce upregulation of PTPN2, thus promoting the progression of laryngocarcinoma.

PATIENTS AND METHODS

PTPN2 levels in laryngocarcinoma tissues and normal tissues were detected. In addition, PTPN2 levels in laryngocarcinoma tissues with stage 1/2 or stage 3/4 were determined as well. In vitro abundance of PTPN2 was measured in laryngocarcinoma cells and immortalized human nasopharyngeal epithelial cells. Survival analysis was conducted in laryngocarcinoma patients with high or low expression level of PTPN2. Subsequently, M4E cells were stimulated with inflammation (IFN-γ or TNF-α treatment) or oxidative stress (H2O2 stimulation), followed by determination of the protein level of PTPN2. In M4E cells stimulated with different concentrations of H2O2, the clonality and Ki-67 positive cell ratio were detected. Finally, clonality and Ki-67 positive cell ratio in M4E cells transfected with negative control or sh-PTPN2, regardless of H2O2 stimulation, were assessed.

RESULTS

PTPN2 was upregulated in laryngocarcinoma tissues, especially those in stage 3/4. Similarly, in vitro abundance of PTPN2 was higher in laryngocarcinoma cell lines. The high level of PTPN2 predicted poor prognosis in laryngocarcinoma patients. IFN-γ or TNF-α treatment upregulated the protein level of PTPN2. Meanwhile, H2O2 stimulation upregulated the protein level of PTPN2, dose-dependently increased clonality, and Ki-67 positive cell ratio in M4E cells. The knockdown of PTPN2 suppressed clonality and Ki-67 positive cell ratio in M4E cells stimulated by H2O2 or not.

CONCLUSIONS

Inflammatory response or oxidative stress could induce upregulation of PTPN2, thus promoting the proliferative ability of laryngocarcinoma.

lncRNA SNHG3 accelerates the proliferation and invasion of non-small cell lung cancer by downregulating miR-340-5p

Small nucleolar RNA host genes (SNHGs) as a subset of long non-coding RNAs (lncRNAs) act critical roles in tumor progression. The present study aimed to elucidate the role and mechanisms of SNHG3 in non-small cell lung cancer (NSCLC). The correlation of SNHG3/miR-340-5p/HOXA10 with the clinicopathological features and outcomes in NSCLC was analyzed by TCGA cohort. In vitro and in vivo functional experiments were conducted to assess the role of SNHG3 in NSCLC cells. Bioinformatic analysis and luciferase gene reporter were used to estimate the interaction between miR-340-5p and SNHG3/HOXA10 3'UTR. The effects of SNHG3 and (or) miR-340-5p on HOXA10 expression were detected by qRT-PCR and Western blot analysis. As a consequence, the elevated expression of SNHG3 and HOXA10 or lowered expression of miR-340-5p was related to the lymph node infiltration, distant metastases and unfavorable prognosis in NSCLC. Ectopic expression of SNHG3 boosted the proliferation and invasion of NSCLC cells in vitro and in vivo, whereas downregulation of SNHG3 reversed these effects. Moreover, SNHG3 could bind with miR-340-5p and reduce its expression levels, and miR-340-5p attenuated SNHG3-induced tumor proliferation and HOXA10 expression in NSCLC cells. Our findings unveiled that SNHG3 might be an oncogenic factor in NSCLC by downregulating miR-340-5p.

[Application of expert consensus to guide the vaccination of children with special health status]

Vaccination of children with special health status has become one of the urgent difficulties to be solved in provinces or regions with high immunization planning vaccination rate. The relevant consensus opinions on vaccination compiled by different expert teams have been issued in China, which provides an important basis for vaccinators to scientifically understand the necessity of vaccination and to study and judge the safety and effectiveness of vaccination. Based on the author's experience of participating in the compilation of a series of consensus on vaccination for children in special health status, this paper discusses how to objectively understand the role of expert consensus and puts forward some suggestions on the wider application of consensus in the future.

Endovascular Recanalization of Symptomatic Nonacute Intracranial Internal Carotid Artery Occlusion: Proposal of a New Angiographic Classification

BACKGROUND AND PURPOSE

The optimal treatment for symptomatic nonacute intracranial ICA occlusion is uncertain, and endovascular recanalization remains a technical challenge. Our purpose was to report multicenter clinical results of endovascular recanalization for medically refractory, nonacute, intracranial ICA occlusion and to propose a new angiographic classification to explore which subgroups of patients are most amenable to this treatment.

MATERIALS AND METHODS

From January 2015 to December 2019, thirty-six consecutive patients who underwent endovascular recanalization for refractory, nonacute, atherosclerotic intracranial ICA occlusion at 3 stroke centers were analyzed retrospectively. The patients were divided into 3 types according to an angiographic classification. Rates of technical success, periprocedural complications, and any stroke or death within 30 days along with follow-up results were evaluated.

RESULTS

The overall technical success rate was 80.6% (29/36), and the rate of any stroke or death within 30 days was 16.7% (6/36). The recanalization success rate gradually decreased from type I to type III in the 3 classification groups (92.9%, 81.3%, and 50%, P = .038), and the opposite was true of the perioperative complication rates (7.1%, 18.8%, and 50%, P = .038). Type I lesions showed favorable recanalization effects, 92.9% technical success rates, and 7.1% perioperative complications.

CONCLUSIONS

Endovascular recanalization for nonacute atherosclerotic intracranial ICA occlusion is technically feasible, especially in patients with type I lesions, and could offer an alternative option for patients with recurrent ischemic symptoms despite aggressive medical therapy. The angiographic classification proposed is conducive to the selection of suitable patients and difficulty in grading.

[Epidemiological study of occupational diseases in Shenzhen City, China in 2006~2017]

Objective: To study the epidemiological characteristics of occupational diseases in Shenzhen City, China in 2006-2017, and to provide a scientific basis for prevention and control of occupational diseases. Methods: Cases of occupational diseases in 2006-2017 were collected from the Information System of Occupational Diseases and Occupational Health. A statistical analysis was performed to identify the characteristics of the disease distribution in terms of spectrum of disease, year, area, industry, type of economy and enterprise scale. Results: A total of 1673 cases of occupational disease (64 types, 8 classes) were diagnosed and reported in 2006-2017, chemical poisoning (31.50%) , ear, nose and throat diseases (28.21%) , and pneumoconiosis and other respiratory diseases (21.34%) were the most three commonest occupational diseases. The constituent of ratio of ear, nose and throat diseases and occupational diseases caused by physical factors increased in turn, the constituent of chemical poisoning, pneumoconiosis and other respiratory diseases, and skin disease reduced in turn, which all showed the difference was statistically significant (P<0.01) . Occupational diseases were often seen in districts of Baoan, Longgang, Longhua and Pingshan, as well as in private economy and small enterprise, mainly occurred in manufacturing industry. Conclusion: The incidence of occupational diseases increased steadily in 2006-2017, and we need to strengthen common occupational diseases, especially occupational noise-induced hearing loss, pay attention to districts of Baoan, Longgang, Longhua and Pingshan, as well as private economy and small enterprise.

Genetic signature of hybridization between Chinese spot-billed ducks and domesticated ducks

In this study, we analyzed 93 whole genomes from Chinese spot-billed ducks (CSB), meat-type ducks (MET), and egg and dual purpose-type ducks (EDT) to characterize the genetic material flowing between the CSB and modern ducks. Using a frequency of shared identical-by-descent method, approximately 10.9 Mb introgression segments containing 140 genes were identified showing the signatures of introgression between CSB and EDT. Meanwhile, nearly 10.6 M introgression regions containing 149 genes were identified between CSB and MET. Based on the haplotypes tree of each segment, we found that the introgression between CSB and domesticated ducks was asymmetric with a high level of gene flow from domestic to CSB and a low level of migration in the opposite direction. Moreover, we identified several genes that were introgressions from CSB and showed the signature of positive selection, which may contribute to the breeding of modern ducks. Our results provide new insight into the evolution and breeding history of domestic ducks and may be useful for the future management of wild and domestic duck populations.

[Efficacy evaluation after 5 years of inoculation of 23 valent pneumococcal polysaccharide vaccine for the elderly aged 60 years old and above in Shanghai during 2013-2018]

Objective: To evaluate the efficacy of 23 valent pneumococcal polysaccharide vaccine (PPV23) inoculation against community-acquired pneumonia (CAP) among the elderly aged 60 years old and above in Shanghai. Methods: A prospective cohort study was conducted using a stratified random sampling from October 2013, in which 1 214 and 2 387 elderly people aged 60 and above were selected as the inoculation group and control group, respectively. And a unified questionnaire was used to investigate the basic information of the subjects in the inoculation group and the control group. From October 2013 to December 2018, the subjects were followed up at home or by telephone for a total of 20 times, mainly for whether they had CAP during the observation period. Multivariate logistic regression model was used to calculate RR and 95%CI of CAP incidence between inoculation group and control group for comparing. Results: There were 556 males (45.8%) in the inoculation group and 1 012 males (42.4%) in the control group. And the incidence density of CAP in the inoculation group was lower than that of the control group (0.848/100 person-years vs. 1.452/100 person-years), and the vaccine protection rate was 41.6%, with a statistically significant difference ［RR (95%CI)= 0.584 (0.428-0.790), P<0.001］. After adjusting for age, RR (95%CI) was 0.699 (0.507-0.956), and the difference was still statistically significant (P=0.025).Further stratified analysis showed that the vaccine protective rates of PPV23 in the 60-69 year-old group, the 70-79 year-old group and the ≥80 year-old group were 36.7%, 21.6% and 26.0%, respectively, but only in the 60-69 year-old group showed statistical difference (RR=0.633, 95%CI=0.399-0.990, P=0.045). Conclusion: To a certain extent, the incidence of CAP can be reduced by inoculation of PPV23 in elderly population aged 60 and above in Shanghai, and it should be further recommended in elderly population of low age.

Specification tests for covariance structures in high-dimensional statistical models

We consider testing the covariance structure in statistical models. We focus on developing such tests when the random vectors of interest are not directly observable and have to be derived via estimated models. Additionally, the covariance specification may involve extra nuisance parameters which also need to be estimated. In a generic additive model setting, we develop and investigate test statistics based on the maximum discrepancy measure calculated from the residuals. To approximate the distributions of the test statistics under the null hypothesis, new multiplier bootstrap procedures with dedicated adjustments that incorporate the model and nuisance parameter estimation errors are proposed. Our theoretical development elucidates the impact due to the estimation errors with high-dimensional data and demonstrates the validity of our tests. Simulations and real data examples confirm our theory and demonstrate the performance of the proposed tests.

[Analysis on the project personnel's attitude and its influential factors of 23-valent pneumococcal polysaccharide vaccination program for the elderly in Shanghai]

Objective: To understand the project personnel's attitude towards the 23-valent pneumococcal polysaccharide vaccination program for the elderly in Shanghai and its conversion to routine vaccination and to explore its influential factors, so as to provide reference for the further development of the program. Methods: In 2016, a one-to-one questionnaire survey was conducted among the people involved in the project in the 9 districts of Shanghai and the data of demographic characteristics, cognition of pneumococcal pneumonia and PPV23, evaluation of the project, support rate of the project and its conversion to routine vaccination of the project personnel were collected. Results: Among the 2005 respondents, 28.6% (574 persons) of them were male, 85.5% (1 714 persons) of them supported the free vaccination for the elderly, and 69.5% of them (1 394 persons) supported the routine vaccination. For the 23-valent pneumococcal polysaccharide vaccination program, people under 55 years old, in Qingpu District, with poor cognition of pneumonia and 23-valent pneumococcal polysaccharide vaccine (PPV23) or having lower evaluation of the project's scientificity or enforceability had lower support rate than others, and the OR (95%CI) were 0.38 (0.19-0.75), 0.21 (0.10-0.43), 0.16 (0.06-0.41) and 0.26 (0.10-0.69). People believing that the elderly were susceptible to pneumococcal pneumonia and PPV23 was safe and reliable, and those who were willing to vaccinate the elderly at home had higher support rate, and the OR (95%CI) were 2.30 (1.18-4.47), 2.84 (1.62-4.69) and 5.60 (3.74-8.38). For the program's conversion to routine vaccination, people under 35 years old, in Qingpu District, in the vaccination clinic, and those believing that the project was not scientific and difficult to implement had low support rate, and the OR (95%CI) were 0.56 (0.32-0.98), 0.48 (0.26-0.89), 0.26 (0.12-0.59), 0.58 (0.42-0.79) and 0.50 (0.30-0.81); people with technical secondary school or senior school, in Jiading, Putuo or Minhang District, believing that PPV23 was effective in the prevention of pneumococcal pneumonia in the elderly, and those who were willing to vaccinate the elderly with PPV23 had higher support rate, and the OR (95%CI) were 1.63 (1.11-2.39), 2.28 (1.71-3.03), 1.69 (1.25-2.28) and 4.10 (2.86-5.88). Conclusion: The support rate of pneumococcal vaccination project for the elderly in Shanghai needs to be improved, especially its conversion to the routine vaccination.

[Safety evaluation of mass inoculation of 23 valent pneumococcal polysaccharide vaccine among elderly people aged 60 and above in Shanghai from 2013 to 2017]

Objective: To evaluate the safety of 23 Valent Pneumococcal Polysaccharide Vaccine (PPV23) among eldly people aged 60 and above in Shanghai. Methods: A total of 1 310 660 monitoring data of adverse events following immunization (AEFI) of PPV23 among people aged 60 and above were collected through the National AEFI Surveillance System from September 14, 2013 to December 31, 2017 in Shanghai. And the descriptive epidemiological methods were used for analysis. Results: 433 cases of AEFI were reported from September 14, 2013 to December 31, 2017, with the incidence rate of AEFI was 33.04/100 000 doses. The general reactions were reported as 392 cases (90.53%), with 17 cases of abnormal reactions (3.93%), 23 cases of coincidences (5.31%) and 1 case of psychogenic reactions (0.23%). The reported incidence rates of general reactions and abnormal reactions of free PPV23 inoculation among elderly people in urban areas were 41.31 per 100 000 doses and 1.91/100 000 doses, respectively, which were higher than those in suburban areas (24.18/100 000 doses, 1.32/100 000 doses) and exurban areas (27.84/100 000 doses, 0.59/100 000 doses). The reported incidence rate of general reaction in females (35.38/100 000 doses) was higher than that in males (24.06/100 000 doses), and the reported incidence rate of abnormal reaction in males (1.58/100 000 doses) was higher than that in females (1.03/100 000 doses). The reported incidence rates of general and abnormal reactions were the highest in 60-64 years old group (62.65/100 000 doses and 4.87/100 000 doses, respectively). In addition, all patients with general reactions or abnormal reactions were better or cured. Conclusion: PPV23 vaccination is safe among people aged 60 and above in Shanghai.

A Microfluidic Approach for Cryoprotectant Screening: Preliminary Validation with Human Red Blood Cells

BACKGROUND

The application of microfluidics has overcome a series of long-term existing bottlenecks in the field of cryobiology. However, there is still no investigation regarding the on-chip rapid screening of cryoprotectant concentration optimization for the integration of the entire freeze, thaw and cell counting process.

OBJECTIVE

To establish an on-chip approach for rapid cryoprotectant screening and concentration optimization.

MATERIALS AND METHODS

Rapid freezing of red blood cells with glycerol and dimethyl sulfoxide was used to validate the proposed on-chip method.

RESULTS

The optimal cryoprotectant and its concentration can be determined with the described method, without the need of additional samplings and assays. The optimal concentration for glycerol and dimethyl sulfoxide used in the validation experiments was 10% (w/v).

CONCLUSION

The microfluidic approach can be used for rapid cryoprotectant screening and concentration optimization.

Genome-wide identification and characterization of microRNAs responding to ABA and GA in maize embryos during seed germination

MicroRNAs (miRNAs) are an important class of non-coding small RNAs that regulate the expression of target genes through mRNA cleavage or translational inhibition. Previous studies have revealed their roles in regulating seed dormancy and germination in model plants such as Arabidopsis thaliana, rice (Oryza sativa) and maize (Zea mays). However, the miRNA response to exogenous gibberellic acid (GA) and abscisic acid (ABA) during seed germination in maize has yet to be explored. In this study, small RNA libraries were generated and sequenced from maize embryos treated with GA, ABA or double-distilled water as control. A total of 247 miRNAs (104 known and 143 novel) were identified, of which 45 known and 53 novel miRNAs were differentially expressed in embryos in the different treatment groups. In total, 74 (37 up-regulated and 37 down-regulated) and 55 (23 up-regulated and 32 down-regulated) miRNAs were expressed in response to GA and to ABA, respectively, and a total of 18 known and 38 novel miRNAs displayed differential expression between the GA- and ABA-treated groups. Using bioinformatics tools, we predicted the target genes of the differentially expressed miRNAs. Using GO enrichment and KEGG pathway analysis of these targets, we showed that miRNAs differentially expressed in our samples affect genes encoding proteins involved in the peroxisome, ribosome and plant hormonal signalling pathways. Our results indicate that miRNA-mediated gene expression influences the GA and ABA signalling pathways during seed germination.