C-X-C Motif Chemokine Ligand 1 Promotes Colitis by Modulating the Gut Microbiota.

INTRODUCTION: C-X-C motif chemokine ligand 1 (CXCL1) is a potent neutrophil chemoattractant that plays a pivotal role in recruiting neutrophils during inflammatory conditions. This study explored the role of CXCL1 in modulating the gut microbiota, influencing neutrophil infiltration, and contributing to the development of colitis. METHODS: We employed quantitative PCR to assess CXCL1 expression in colon samples. A mouse model of dextran sulfate sodium (DSS)-induced colitis was utilized to explore the progression of colitis in wild-type (WT) and CXCL1-deficient (CXCL1-/-) mice. RESULTS: Colitis attenuation was evident in CXCL1-/- mice. Significant alterations were observed in the gut microbiome, as revealed by 16S rRNA gene sequencing. Furthermore, CXCL1-/- mice exhibited reduced gut permeability and diminished endotoxin levels in peripheral blood following DSS treatment compared to WT mice. In response to DSS treatment, WT mice showed a clear increase in neutrophil infiltration, while CXCL1-/- mice exhibited lower levels of infiltration. Fecal microbiota transplantation (FMT) using stools from CXCL1-/- mice alleviated DSS-induced colitis. Interestingly, FMT from patients with colitis increased CXCL1 and Ly6G expression in the colons of gut-sterilized mice. Clinical data analysis revealed elevated CXCL1 and CD15 expression in patients with colitis, with a positive correlation between the severity of colitis and the expression of CXCL1 and CD15. CONCLUSION: These findings shed light on the pivotal role of CXCL1 in promoting colitis by modulating the gut microbiota.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles Promote the Proliferation of Schwann Cells by Regulating the PI3K/AKT Signaling Pathway via Transferring miR-21.

As an alternative mesenchymal stem cell- (MSC-) based therapy, MSC-derived extracellular vesicles (EVs) have shown promise in the field of regenerative medicine. We previously found that human umbilical cord mesenchymal stem cell-derived EVs (hUCMSC-EVs) improved functional recovery and nerve regeneration in a rat model of sciatic nerve transection. However, the underlying mechanisms are poorly understood. Here, we demonstrated for the first time that hUCMSC-EVs promoted the proliferation of Schwann cells by activating the PI3K/AKT signaling pathway. Furthermore, we showed that hUCMSC-EVs mediated Schwann cell proliferation via transfer of miR-21. Our findings highlight a novel mechanism of hUCMSC-EVs in treating peripheral nerve injury and suggest that hUCMSC-EVs may be an attractive option for clinical application in the treatment of peripheral nerve injury.

Down-regulation of long non-coding RNA MEG3 promotes Schwann cell proliferation and migration and repairs sciatic nerve injury in rats.

Peripheral nerve injury and regeneration are complex processes and involve multiple molecular and signalling components. However, the involvement of long non-coding RNA (lncRNA) in this process is not fully clarified. In this study, we evaluated the expression of the lncRNA maternally expressed gene 3 (MEG3) in rats after sciatic nerve transection and explored its potential mechanisms. The expression of lncRNA MEG3 was up-regulated following sciatic nerve injury and observed in Schwann cells (SCs). The down-regulation of lncRNA MEG3 in SCs enhanced the proliferation and migration of SCs via the PTEN/PI3K/AKT pathway. The silencing of lncRNA MEG3 promoted the migration of SCs and axon outgrowth in rats after sciatic nerve transection and facilitated rat nerve regeneration and functional recovery. Our findings indicated that lncRNA MEG3 may be involved in nerve injury and injured nerve regeneration in rats with sciatic nerve defects by regulating the proliferation and migration of SCs. This gene may provide a potential therapeutic target for improving peripheral nerve injury.

[Rat bone marrow mesenchymal stem cells promote apoptosis and inhibit proliferation and migration of RSC96 cells].

Objective: To investigate the effect of rat bone marrow mesenchymal stem cells( BMSCs) on the proliferation and migration of rat RSC96 Schwann cells in vitro. Methods: BMSCs of Sprague Dawley( SD) rats were isolated by bone marrow cell adherent method. The morphology of the third generation of BMSCs was observed by inverted microscopy. The cell surface antigen makers CD19,CD34,CD73,CD105 were detected by flow cytometry. The third-passage BMSCs differentiated into osteoblasts and adipocytes after exposed to bone-inducing and lipid-inducing media for 3 and 2 weeks,respectively,and then were identified by oil red O and alkaline phosphatase staining. The third generation of BMSCs was co-cultured with RSC96 cells for 24 hours in 24 mm co-culture plate. The cell proliferation and colony formation of RSC96 cells were determined by MTT assay and plate cloning assay. The migration of RSC96 cells was detected by scratch and TranswellTMchamber assay. Bax and Bcl-2 expression levels of RSC96 cells were detect by Western blot analysis. Results: The third generation of BMSCs showed fusiform,spiral arrangement with similar cell size under an inverted microscope. The CD73 and CD105 expression levels of BMSCs were high,however,the CD34 and CD19 were low. BMSCs had large lipid droplets after adipogenic induction for 3 weeks; and the alkaline phosphatase staining of BMSCs was positive after osteogenic induction for 2 weeks. Compared to the control group,co-culture of RSC96 cells and BMSCs induced a significant decrease in the proliferation,colony formation and migration of RSC96 cells. Meanwhile,Bax protein expression increased,and Bcl-2protein expression decreases in RSC96 cells co-cultured with BMSCs. Conclusion: BMSCs could promote the apoptosis and inhibit the proliferation and migration of RSC96 cells.

Multiresidue determination of organophosphorus pesticides in solid waste environmental samples by gas chromatography.

The method for the determination of 12 organophosphorus pesticides in solid waste was established. The organophosphorus pesticides were analyzed by Soxhlet extraction or accelerated solvent extraction (ASE)-SPE cartridge-flame photometric detector (FPD), and leaching solution by rotary oscillation-positive pressure filtration-liquid-liquid extraction-SPE cartridge-FPD. The differences of extraction efficiencies between Soxhlet and ASE were compared. Solvent of Soxhlet extraction, purification and recovery of organophosphorus pesticides in leaching conditions were also studied. The recoveries were 54.2-119.8%, and the average recovery was 87.7%. The RSD was 1.89-9.10% (n = 6), the average RSD was 6.88%, and the detection limit was 0.27-0.69 µg/kg.