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Methods:Cultured human alveolar epithelial A549 cells were assigned into LPS group and blank control group. LPS group was stimulated with LPS and adenosine triphosphate to induce pyroptosis and inflammation. A549 cells were divided into 4 groups: miR-20a mimics group, mimics-negative control (NC) group, inhibitor group and inhibitor-NC group. MiRNA-20a mimics, mimics-NC, inhibitor, and inhibitor-NC were transfected respectively into A549 cells, and after 24 h, the cells were collected to verify transfection efficiency by qPCR. MiRNA-20a mimics and the constructed TLR4-3'UTR double luciferase reporter plasmid were co-transfected into A549 cells, and luciferase activity was analyzed. MiRNA-20a mimics/inhibitors were transfected into A549 cells, and then the cells were stimulated by LPS for 8 h followed by adenosine triphosphate for 30 min. QPCR, Western Blot and ELISA were used to detect the expression of GSDMD, inflammatory factors (ASC, NLRP3, Caspase-1, IL-1β) and Signaling molecules (TLR4、NF-κB) in A549 cells at mRNA level and protein level. Immunofluorescence was used to detect the expression of TLR4 in the A549 cells and NF-κB in the nucleus of A549 cells after transfecting with miRNA-20a mimics/inhibitor.Results:The mRNA and protein expression of pyroptosis marker molecule (GSDMD) and inflammatory factors (ASC, NLRP3, Caspase-1, IL-1β) in A549 cells stimulated with LPS were significantly higher than those in the blank control group, and the differences were statistically significant ( P<0.05). The expression of miRNA-20 in the mimics group was significantly higher than that in the mimic-NC group ( P<0.05), while the expression of miRNA-20a in the inhibitor group was lower than that in the inhibitor-NC group ( P<0.01). The double luciferase reporter gene experiment showed that the relative fluorescence value of the co-transfection group for TLR4-3'UTR-WT and miRNA-20a mimics was significantly lower than the co-transfection group for TLR4-3'UTR-WT and miRNA-20a mimics-NC ( P<0.05). The mRNA and protein levels of pyroptosis marker molecule (GSDMD) , inflammatory factors (ASC, NLRP3, Caspase-1, IL-1β) and signaling molecules (TLR4, NF-κB) were decreased in the mimics group compared to the mimics-NC group, and increased in inhibitor group compared to inhibitor-NC group. Conclusions:miRNA-20a may inhibit LPS-induced pyroptosis and inflammation of A549 cells via TLR4/NF-κB signal pathway.Objetive:To explore the potential role of miRNA-20a in lipopolysaccharide (LPS) induced pyroptosis and inflamation of human alveolar epithelial A549 cells and its regulation mechanisim.
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The establishment and development of the intestinal microbiota in early life is critical to the development of intestinal immune system,digestive function,metabolic function,and central nervous system function in infants.The first 1000 days of life is a critical period for the establishment of intestinal microbiota,which is susceptible to many factors.The disorder of intestinal microbiota in this period will increase the risk of some diseases in the long-term life.In this review,we will describe the main physiological functions of the early-life microbiota and its role in programming future health of infants.We also will describe the establishment and development of the intestinal microbiota in early life and its main drivers.
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The establishment and development of the intestinal microbiota in early life is critical to the development of intestinal immune system, digestive function, metabolic function, and central nervous system function in infants.The first 1000 days of life is a critical period for the establishment of intestinal microbiota, which is susceptible to many factors.The disorder of intestinal microbiota in this period will increase the risk of some diseases in the long-term life.In this review, we will describe the main physiological functions of the early-life microbiota and its role in programming future health of infants.We also will describe the establishment and development of the intestinal microbiota in early life and its main drivers.
RESUMO
Objective To investigate the characteristics of intestinal microbiota in neonates on the first and third day after birth.Methods A total of 50 healthy singleton neonates who were born between June 15,2016 and August 3,2016 in Shanghai First Maternity and Infant Hospital were enrolled.Their stool samples were collected on the first and third day after birth and the samples were labeled according to the time of collection (D1 and D3 groups,n=50 each).Illumina NexSeq high-throughput sequencing platform was used to sequence the variable region 4 and 5 of all bacterial 16S rRNA genes in the samples.The composition of intestinal microbial communities was determined and the differences between the two groups were compared by Metastats analysis.Results (1) A total of 100 stool samples were sequenced and the retrieved sequences were from 25 bacterial phyla,119 families,227 genera and 159 species.(2) Major phyla in the two groups were the same,namely,Proteobacteria,Frimicutes,Bacteroidetes and Actinobacteria.The relative abundances of Frimicutes (0.27 ± 0.03 vs 0.41 ± 0.05) and Bacteroidetes (0.07 ± 0.01 vs 0.09 ± 0.03) increased over time,while that of Actinobacteria (0.10±0.01 vs 0.01 ±0.00) decreased on day 3.No significant difference in the relative abundance of Proteobacteria (0.51 ±0.03 vs 0.49± 0.05) was observed between D1 and D3 groups.There were significant difference in relative abundances of Frimicutes and Actinobacteria between the two groups (both q=-0.01,both P＜0.05).(3) Among the top ten most abundant families,Enterobacteriaceae,Staphylococcaceae,Enterococcaceae,Streptococcaceae and Lachnospiraceae were detected in both of the two groups.The relative abundances of Enterobacteriaceae (0.25 ± 0.02 vs 0.46 ± 0.06),Staphylococcaceae (0.07 ± 0.02 vs 0.12 ± 0.03),Enterococcaceae (0.04±0.02 vs 0.10±0.04),Streptococcaceae (0.03 ±0.02 vs 0.06±0.01) increased over time,while that of Lachnospiraceae (0.03 ± 0.01 vs 0.02 ± 0.02) decreased on day 3.Only the relative abundance of Enterobacteriaceae had statistical difference between the two groups (q=0.00,P＜0.05).(4) Among the top ten most abundant genera,Staphylococcus,Enterococcus,Streptococcus,Bacteroides and Pseudomonas were detected in both groups.The relative abundances of aerobic and facultative anaerobic bacteria which belonged to genera of Stenotrophomonas,Propionibacterium,Acinetobacter,Bacillus,Sphingomonas and so on decreased on day 3 as compared with those on day 1 (0.00±0.00 vs 0.07±0.02,0.00±0.00 vs 0.06±0.01,0.00±0.00 vs 0.03±0.01,0.00±0.00 vs 0.02±0.01,0.00±0.00 vs 0.02±0.00,all q=0.00,all P＜0.05).However,the relative abundances of anaerobic bacteria which belonged to Bacteroides,Veillonella,Parabacteroides and so on increased on day 3 (0.01 ±0.00 vs 0.08±0.03,0.00±0.00 vs 0.03±0.02,0.00±0.00 vs 0.01 ±0.00,q=0.01,0.01 and 0.00,all P＜0.05).(5) The most abundant species in intestinal microbiota was escherichia coli in both groups.Three less abundant species including lactobacillus gasseri,lactobacillus animalis and bifidobacterium bifidum were detected in both groups.(6) Regardless of the mode of delivery,Staphylococcus,was the highest predominant genera in meconium samples,followed by stenotrophomonas.Stool samples collected on the third day after birth were divided into four groups based on deliver modes and feeding patterns.Neonates who were born abdominally with exclusive breastfed thereafter were different from those of the other three groups in predominant intestinal bacteria,but the difference was not statistically significant.Bifidobacterium and Subdoligranulum were only detected in the vaginally born neonates.Conclusions Meconium is not sterile.Although the intestinal microbiota on the first day of life is different from that on the third day of life,the dominant bacteria are common.During the first three days of life,the relative abundances of aerobic and facultative anaerobic bacteria decreased significantly over time,while the relative abundance of anaerobic bacteria increased.