RNA sequencing uncover crucial genes mediating progression of large-artery atherosclerotic and small-artery occlusion ischemic stroke.

PURPOSE: The goal of our study is to uncover the pathogenesis of large-artery atherosclerotic ischemic stroke (LAAIS) and small-artery occlusion ischemic stroke (SAOIS) and analyze their difference using RNA sequencing. METHODS: RNA sequencing was used to filtrate differentially expressed mRNAs (DEmRNAs) and differentially expressed lncRNAs (DElncRNAs) in LAAIS and SAOIS. Specific DEmRNAs and DElncRNAs in LAAIS and SAOIS were further found. Functional annotation and DElncRNA-DEmRNA co-expression network were built to reveal biological function of DEmRNAs. RESULTS: A total of 832 DEmRNAs and 96 DElncRNAs were identified in LAAIS vs normal controls. 587 DEmRNAs and 105 DElncRNAs were identified in SAOIS vs normal controls. In LAAIS vs SAOIS, 636 DEmRNAs and 112 DElncRNAs were identified. Among which, 571 DEmRNAs and 61 DElncRNAs were LAAIS specific DEmRNAs and DElncRNAs, respectively. 325 DEmRNAs and 66 DElncRNAs were respectively SAOIS specific DEmRNAs and DElncRNAs. We also obtained 3086 LAAIS specific DElncRNA-DEmRNA co-expression pairs and 661 SAOIS specific DElncRNA-DEmRNA co-expression pairs. Oxidative phosphorylation and Alzheimer's disease were significantly enriched pathways in both LAAIS specific DEmRNAs and DEmRNAs in LAAIS specific DElncRNA-DEmRNA co-expression network. ECM-receptor interaction, hypertrophic cardiomyopathy and dilated cardiomyopathy were significantly enriched pathways in both SAOIS specific DEmRNAs and DEmRNAs in SAOIS specific DElncRNA-DEmRNA co-expression network. CONCLUSION: This finding may help to understand the mechanisms of LAAIS and SAOIS and offer novel clues for finding specific biomarkers for LAAIS and SAOIS.

Identification of Gut Microbiome Signatures in Patients With Post-stroke Cognitive Impairment and Affective Disorder.

Stroke (ST), endangering human health due to its high incidence and high mortality, is a global public health problem. There is increasing evidence that there is a link between the gut microbiota (GM) and neuropsychiatric diseases. We aimed to find the GM of ST, post-ST cognitive impairment (PSCI), and post-ST affective disorder (PSTD). GM composition was analyzed, followed by GM identification. Alpha diversity estimation showed microbiota diversity in ST patients. Beta diversity analysis showed that the bacterial community structure segregated differently between different groups. At the genus level, ST patients had a significantly higher proportion of Enterococcus and lower content of Bacteroides, Escherichia-Shigella, and Megamonas. PSCI patients had a significantly higher content of Enterococcus, Bacteroides, and Escherichia-Shigella and a lower proportion of Faecalibacterium compared with patients with ST. Patients with PSTD had a significantly higher content of Bacteroides and Escherichia-Shigella and lower content of Enterococcus and Faecalibacterium. Parabacteroides and Lachnospiraceae were associated with Montreal cognitive assessment score of ST patients. Our study indicated that the characteristic GM, especially Bacteroidetes, could be used as clinical biomarkers of PSCI and PSTD.

Screening for differentially expressed circRNAs in ischemic stroke by RNA sequencing.

BACKGROUND: Ischemic stroke is a disease with high rate of death and disability worldwide. CircRNAs, as a novel type of non-coding RNAs, lacking 5' caps and 3' poly-A tails, has been associated with ischemic stroke. This study aimed to investigate key circRNAs related to ischemic stroke. METHODS: RNA sequencing was performed obtain the circRNA expression profiles from peripheral whole blood of three ischemic stroke patients and three healthy individuals. Through bioinformatic analysis, differentially expressed circRNAs (DEcircRNAs) were identified, and GO and pathway analyses for the host genes of DEcircRNAs were conducted. The expression levels of selected circRNAs were analyzed with qRT-PCR. To further explore the functions of key circRNAs, a DEcircRNA-miRNA interaction network was constructed. RESULTS: A total of 736 DEcircRNAs were detected in ischemic stroke. Functional annotation of host genes of DEcircRNAs revealed several significantly enriched pathways, including Fc epsilon RI signaling pathway, B cell receptor signaling pathway, and T cell receptor signaling pathway. The qRT-PCR results were largely in keeping with our RNA-seq data. The ROC curve analyses indicated that hsa_circ_0000745, hsa_circ_0001459, hsa_circ_0003694 and hsa_circ_0007706 with relatively high diagnostic value. A circRNA-miRNA network, including 1544 circRNA-miRNA pairs, 456 circRNAs and 4 miRNAs, was obtained. CONCLUSIONS: The results of our study may help to elucidate the specific mechanism underlying ischemic stroke.

Conjunctival Expression of Toll-Like Receptor 3 Plays a Pathogenic Role in the Formation of Ultraviolet Light-Induced Pterygium.

Purpose: Toll-like receptor 3 (TLR3), as a damage-associated molecular pattern sensor, can detect self-RNA released from necrotic cells induced by ultraviolet B (UVB) radiation exposure. Pterygium formation is believed to be a tumorigenesis-like process induced by UVB exposure. In this study, we aimed to investigate the expression pattern of TLR3 in pterygium specimens and cultured pterygial epithelial cells (PECs). Methods: Human pterygium and ipsilateral pterygium-free conjunctiva from the same patients were used in this study. The expression of TLR3 and nuclear factor-kappa B (NF-κB) was investigated in these specimens. PECs were exposed to UVB radiation to determine the effect of UVB on the expression of TLR3 and the activation of NF-κB. Results: The immunofluorescence study showed stronger TLR3 expression in superficial epithelial cells in the pterygial epithelium in comparison with the normal conjunctival epithelium. The expression of TLR3 decreased in intensity from the superficial epithelium toward the basal cell layer, implying a correlation between UVB exposure and TLR3 expression. Differential TLR3 expression patterns in pterygial and conjunctival tissues were also found in quantitative PCR analyses. PECs after UVB irradiation had higher protein levels of TLR3 and phospho-NF-κB than those of the PECs without irradiation. Immunofluorescence studies showed that UVB irradiation induced the nuclear translocation of NF-κB in the PECs. In PECs with the targeted TLR3 gene silencing, the expression of phospho-NF-κB was not induced by UVB irradiation. Conclusions: Our results indicate that UVB exposure, TLR3 expression, and NF-κB activation may be a critical sequence that leads to the formation of pterygium.

Dipeptide HCH6-1 inhibits neutrophil activation and protects against acute lung injury by blocking FPR1.

Formyl peptide receptor 1 (FPR1) is an emerging therapeutic target for the discovery of drugs to treat neutrophilic inflammatory diseases. However, development of FPR1 antagonists for clinical use is still inadequate. The purpose of this study was to identify a synthetic dipeptide N-(N-benzoyl-L-tryptophanyl)-D-phenylanlanine methyl ester (HCH6-1) as a FPR1 inhibitor and to investigate its protective effects against acute lung injury (ALI). HCH6-1 inhibited superoxide anion generation, elastase release, and chemotaxis in human neutrophils specifically activated by formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLF), an FPR1 agonist. HCH6-1 produced right shifts in the concentration-response curves of fMLF, suggesting that HCH6-1 was a competitive antagonist of FPR1. Indeed, HCH6-1 bound to FPR1 in human neutrophils and neutrophil-like THP-1 as well as hFPR1-transfected HEK293 cells. Also, the FPR1 downstream signaling pathways were competitively inhibited by HCH6-1. Furthermore, HCH6-1 prevented pulmonary neutrophil infiltration and edema along with alveolar damage in LPS-induced ALI in mice. Our findings suggest that HCH6-1, a FPR1 antagonist, may have potential as a new therapeutic agent for treating FPR1-involved inflammatory lung diseases.

Bioactive secondary metabolites of a marine Bacillus sp. inhibit superoxide generation and elastase release in human neutrophils by blocking formyl peptide receptor 1.

It is well known that overwhelming neutrophil activation is closely related to acute and chronic inflammatory injuries. Formyl peptide receptor 1 (FPR1) plays an important role in activation of neutrophils and may represent a potent therapeutic target in inflammatory diseases. In the present study, we demonstrated that IA-LBI07-1 (IA), an extract of bioactive secondary metabolites from a marine Bacillus sp., has anti-inflammatory effects in human neutrophils. IA significantly inhibited superoxide generation and elastase release in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-activated neutrophils, but failed to suppress the cell responses activated by non-FPR1 agonists. IA did not alter superoxide production and elastase activity in cell-free systems. IA also attenuated the downstream signaling from FPR1, such as the Ca2+, MAP kinases and AKT pathways. In addition, IA inhibited the binding of N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein, a fluorescent analogue of FMLP, to FPR1 in human neutrophils and FPR1-transfected HEK293 cells. Taken together, these results show that the anti-inflammatory effects of IA in human neutrophils are through the inhibition of FPR1. Also, our data suggest that IA may have therapeutic potential to decrease tissue damage induced by human neutrophils.

Design and synthesis of tryptophan containing dipeptide derivatives as formyl peptide receptor 1 antagonist.

Our previous studies identified an Fmoc-(S,R)-tryptophan-containing dipeptide derivative, 1, which selectively inhibited neutrophil elastase release induced by formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) in human neutrophils. In an attempt to improve pharmacological activity, a series of tryptophan-containing dipeptides were synthesized and their pharmacological activities were investigated in human neutrophils. Of these, five compounds 3, 6, 19a, 24a, and 24b exhibited potent and dual inhibitory effects on FMLP-induced superoxide anion (O2˙(-)) generation and neutrophil elastase release in neutrophils with IC50 values of 0.23/0.60, 1.88/2.47, 1.87/3.60, 0.12/0.37, and 1.32/1.03 µM, respectively. Further studies indicated that inhibition of superoxide production in human neutrophils by these dipeptides was associated with the selective inhibition of formyl peptide receptor 1 (FPR1). Furthermore, the results of structure-activity relationship studies concluded that the fragment N-benzoyl-Trp-Phe-OMe (3) was most suitable as a core structure for interaction with FPR1, and may be approved as a lead for the development of new drugs in the treatment of neutrophilic inflammatory diseases. As some of the synthesized compounds exhibited separable conformational isomers, and showed diverse bioactivities, the conformation analysis of these compounds is also discussed herein.

Propofol inhibits superoxide production, elastase release, and chemotaxis in formyl peptide-activated human neutrophils by blocking formyl peptide receptor 1.

Neutrophils play a critical role in acute and chronic inflammatory processes, including myocardial ischemia/reperfusion injury, sepsis, and adult respiratory distress syndrome. Binding of formyl peptide receptor 1 (FPR1) by N-formyl peptides can activate neutrophils and may represent a new therapeutic target in either sterile or septic inflammation. Propofol, a widely used i.v. anesthetic, has been shown to modulate immunoinflammatory responses. However, the mechanism of propofol remains to be established. In this study, we showed that propofol significantly reduced superoxide generation, elastase release, and chemotaxis in human neutrophils activated by fMLF. Propofol did not alter superoxide generation or elastase release in a cell-free system. Neither inhibitors of γ-aminobutyric acid receptors nor an inhibitor of protein kinase A reversed the inhibitory effects of propofol. In addition, propofol showed less inhibitory effects in non-FPR1-induced cell responses. The signaling pathways downstream from FPR1, involving calcium, AKT, and ERK1/2, were also competitively inhibited by propofol. These results show that propofol selectively and competitively inhibits the FPR1-induced human neutrophil activation. Consistent with the hypothesis, propofol inhibited the binding of N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein, a fluorescent analog of fMLF, to FPR1 in human neutrophils, differentiated THP-1 cells, and FPR1-transfected human embryonic kidney-293 cells. To our knowledge, our results identify, for the first time, a novel anti-inflammatory mechanism of propofol by competitively blocking FPR1 in human neutrophils. Considering the importance of N-formyl peptides in inflammatory processes, our data indicate that propofol may have therapeutic potential to attenuate neutrophil-mediated inflammatory diseases by blocking FPR1.