LncRNA Gm26917 regulates inflammatory response in macrophages by enhancing Annexin A1 ubiquitination in LPS-induced acute liver injury

The mouse retinal pigment epithelium mounts an innate immune defense response following retinal detachment

The retinal pigment epithelium (RPE) maintains photoreceptor viability and function, completes the visual cycle, and forms the outer blood-retinal barrier (oBRB). Loss of RPE function gives rise to several monogenic retinal dystrophies and contributes to age-related macular degeneration. Retinal detachment (RD) causes separation of the neurosensory retina from the underlying RPE, disrupting the functional and metabolic relationships between these layers. Although the retinal response to RD is highly studied, little is known about how the RPE responds to loss of this interaction. RNA sequencing (RNA-Seq) was used to compare normal and detached RPE in the C57BL6/J mouse. The naïve mouse RPE transcriptome was compared to previously published RPE signature gene lists and from the union of these 14 genes (Bmp4, Crim1, Degs1, Gja1, Itgav, Mfap3l, Pdpn, Ptgds, Rbp1, Rnf13, Rpe65, Slc4a2, Sulf1 and Ttr) representing a core signature gene set applicable across rodent and human RPE was derived. Gene ontology enrichment analysis (GOEA) of the mouse RPE transcriptome identified expected RPE features and functions, such as pigmentation, phagocytosis, lysosomal and proteasomal degradation of proteins, and barrier function. Differentially expressed genes (DEG) at 1 and 7 days post retinal detachment (dprd) were defined as mRNA with a significant (padj≤0.05) fold change (FC) of 0.67 ≥ FC ≥ 1.5 in detached versus naïve RPE. The RPE transcriptome exhibited dramatic changes at 1 dprd, with 2297 DEG identified. The KEGG pathways and biological process GO groups related to innate immune responses were significantly enriched. Lipocalin 2 (Lcn2) and several chemokines were upregulated, while numerous genes related to RPE functions, such as pigment synthesis, visual cycle, phagocytosis, and tight junctions were downregulated at 1 dprd. The response was largely transient, with only 18 significant DEG identified at 7 dprd, including upregulation of complement gene C4b. Validation studies confirmed RNA-Seq results. Thus, the RPE quickly downregulates cell-specific functions and mounts an innate immune defense response following RD. Our data demonstrate that the RPE contributes to the inflammatory response to RD and may play a role in attraction of immune cells to the subretinal space.

Aralia saponin A isolated from Achyranthes bidentata Bl. ameliorates LPS/D-GalN induced acute liver injury via SPHK1/S1P/S1PR1 pathway in vivo and in vitro

OBJECTIVE

Acute liver injury (ALI) refers to a disease in which the liver is affected by factors such as chemical substances, alcohol, and virus infection in a short time, resulting in damage to liver cells. Achyranthes bidentata Bl. with the hepatoprotective activity has attracted great attention. In this study, a pentacyclic triterpenoid (Aralia saponin A, AsA) was isolated from roots of Achyranthes bidentata Bl. and its anti-ALI activity, as well as the mechanisms, were investigated for the first time.

METHODS

AsA (10 or 20 mg/kg, i.g.) was administered over a period of 1 weeks, following which liver injury was induced by LPS (10 µg/kg)/D-GalN (700 mg/kg). H&E staining of liver, Aspartate amino transferase (AST), Alanine transaminase (ALT) and cytokines was employed to investigate ALI relevant features. The mitochondrial morphology and levels of mitochondrial membrane potential (MMP), oxidative stress balance, apoptosis, average fluorescence intensity of 2-DG, natural killer (NK) cells in liver tissues were determined to assess the oxidative stress damage and inflammatory injury. Transcriptomics and metabonomics analysis were employed to clarify the mechanisms. Additionally, the mRNA and protein expression levels of Sphingosine 1-phosphate (S1P), Sphingosine kinase-1 (SPKH1), Sphingosine 1 phosphate receptor 1 (S1PR1), Sphingosine 1 phosphate receptor 3 (S1PR3), TNF receptor associated factor 2 (TRAF-2), Phospho-NF- kappaB p65 (p-P65), NF- kappaB p65 (P65), Proto-oncogene ras (Ras), Ras-related C3 botulinum toxin substrate (Rac), Phospholipase C (PLC), Interleukin 6 (IL-6), Tumor necrosis factor α (TNF-α), Interleukin 1β (IL-1β), Vascular cell adhesion molecule 1 (Vcam1), CC chemokine ligand-2 (Ccl2) were analyzed. The mediating role of SPHK1 in the observed effects caused by AsA was assessed by investigatin SPHK1 transfection silencing/overexpression against AsA in AML12 cells induced by LPS/D-GalN.

RESULTS

AsA can ameliorate liver function, inflammation, mitochondrial structure and oxidative stress in the ALI model. Meanwhile, AsA led to downregulated expression of proteins associated with sphingolipid signaling pathway. Silencing of SPHK1 led to enhanced protective effects of AsA, while over-expression of SPHK1 led to degraded protective effects of AsA in LPS/D-GalN-induced AML12 cells, suggesting that ALI is regulated by active molecules of AsA by means of SPHK1 mediation.

CONCLUSIONS

AsA can ameliorate LPS/D-GalN-induced ALI by inhibiting inflammation and oxidative stress via the SPHK1/S1P/S1PR1 pathway. In this way, a molecular justification is provided for AsA application in ALI treatment.

Integrated Analysis of Non-Coding RNA and mRNA Expression Profiles in Exosomes from Lung Tissue with Sepsis-Induced Acute Lung Injury

Background

Acute lung injury (ALI) is associated with a high mortality rate; however, the underlying molecular mechanisms are poorly understood. The purpose of this study was to investigate the expression profile and related networks of long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and mRNAs in lung tissue exosomes obtained from sepsis-induced ALI.

Methods

A mouse model of sepsis was established using the cecal ligation and puncture method. RNA sequencing was performed using lung tissue exosomes obtained from mice in the sham and CLP groups. Hematoxylin-eosin staining, Western blotting, immunofluorescence, quantitative real-time polymerase chain reaction, and nanoparticle tracking analysis were performed to identify relevant phenotypes, and bioinformatic algorithms were used to evaluate competitive endogenous RNA (ceRNA) networks.

Results

Thirty lncRNA-miRNA-mRNA interactions were identified, including two upregulated lncRNAs, 30 upregulated miRNAs, and two downregulated miRNAs. Based on the expression levels of differentially expressed mRNAs(DEmRNAs), differentially expressed LncRNAs(DELncRNAs), and differentially expressed miRNAs(DEmiRNAs), 30 ceRNA networks were constructed.

Conclusion

Our study revealed, for the first time, the expression profiles of lncRNA, miRNA, and mRNA in exosomes isolated from the lungs of mice with sepsis-induced ALI, and the exosome co-expression network and ceRNA network related to ALI in sepsis.

Uncovering the Gene Regulatory Network of Endothelial Cells in Mouse Duchenne Muscular Dystrophy: Insights from Single-Nuclei RNA Sequencing Analysis

Introduction: Duchenne muscular dystrophy (DMD) is a severe X-linked recessive disorder caused by mutations in the dystrophin gene, which leads to heart and respiratory failure. Despite the critical impact of DMD on endothelial cells (ECs), there is limited understanding of its effect on the endothelial gene network. The aim of this study was to investigate the impact of DMD on the gene regulatory network of ECs. Methods and Results: To gain insights into the role of the dystrophin muscular dystrophy gene (DMD) in ECs from Duchenne muscular dystrophy; the study utilized single-nuclei RNA sequencing (snRNA-seq) to evaluate the transcriptomic profile of ECs from skeletal muscles in DMD mutant mice (DMDmut) and wild-type control mice. The analysis showed that the DMD mutation resulted in the suppression of several genes, including SPTBN1 and the upregulation of multiple long noncoding RNAs (lncRNAs). GM48099, GM19951, and GM15564 were consistently upregulated in ECs and skeletal muscle cells from DMDmut, indicating that these dysregulated lncRNAs are conserved across different cell types. Gene ontology (GO) enrichment analysis revealed that the DMD mutation activated the following four pathways in ECs: fibrillary collagen trimer, banded collagen fibril, complex of collagen trimers, and purine nucleotide metabolism. The study also found that the metabolic pathway activity of ECs was altered. Oxidative phosphorylation (OXPHOS), fatty acid degradation, glycolysis, and pyruvate metabolism were decreased while purine metabolism, pyrimidine metabolism, and one carbon pool by folate were increased. Moreover, the study investigated the impact of the DMD mutation on ECs from skeletal muscles and found a significant decrease in their overall number, but no change in their proliferation. Conclusions: Overall, this study provides new insights into the gene regulatory program in ECs in DMD and highlights the importance of further research in this area.