Mesenchymal Stem Cells Promote Polarization of M2 Macrophages in Mice with Acute-On-Chronic Liver Failure via Mertk/JAK1/STAT6 Signaling.

Acute-on-chronic liver failure (ACLF) is a severe disease with a high mortality. Macrophage-related inflammation plays a crucial role in ACLF development. Mesenchymal stem cells (MSCs) treatment was demonstrated to be beneficial in ACLF in our previous study; however, the underlying mechanisms remain unknown. Therefore, mouse bone marrow-derived MSCs were used to treat an ACLF mouse model or cocultured with RAW264.7/J774A.1 macrophages that were stimulated with LPS. Histological and serological parameters and survival were analyzed to evaluate efficacy. We detected changes of Mer tyrosine kinase (Mertk), JAK1/STAT6, inflammatory cytokines, and markers of macrophage polarization in vitro and in vivo. In ACLF mice, MSCs improved liver function and 48-h survival of ACLF mice and alleviated inflammatory injury by promoting M2 macrophage polarization and elevated Mertk expression levels in macrophages. This is significant, as Mertk regulates M2 macrophage polarization via the JAK1/STAT6 signaling pathway.

Ferrostatin-1 Polarizes Microglial Cells Toward M2 Phenotype to Alleviate Inflammation After Intracerebral Hemorrhage.

BACKGROUND: Intracerebral hemorrhage (ICH) is one of the most lethal stroke types and lacks effective therapeutic regimens. Recently, evidence has suggested the involvement of the ferroptosis inhibitor ferrostatin-1 (Fer-1) in the pathophysiological process of ICH. In this study, we examined the underlying mechanism. METHODS: We induced an in vitro apoptosis model in organotypic hippocampal slice (OHS) using hemoglobin (Hb) and an in vivo ICH model using collagenase. OHSs were treated with MK-801, Fer-1, glutamate, and Hb to assess the impacts of Fer-1 on neuron apoptosis, glutathione peroxidase-4 activity, reactive oxygen species production, inflammation-related factors, expression of M1 markers and M2 markers, and the phagocytic function of microglial cells in vitro. Then, ICH mice were treated with Fer-1 and ruxolitinib to evaluate the effects of Fer-1-orchestrating janus kinase 1/signal transducer and activator of transcription 6 pathway on neurological function, brain water content, hematoma volume, the anti-inflammatory factor, M1 and M2 markers, and the phagocytic function of microglial cells in vivo. RESULTS: Hb or glutamate facilitated glutathione peroxidase dysfunction, reactive oxygen species production, and neuronal apoptosis in OHSs, which was nullified by Fer-1. Fer-1 polarized microglial cells to the M2 phenotype, enhanced their phagocytic function, and prevented inflammation in Hb-induced OHSs. In the ICH mouse model, Fer-1 was found to improve neurological function and promote hematoma absorption. In addition, Fer-1 activated the Fer-1-orchestrating janus kinase 1/signal transducer and activator of transcription 6 pathway, which accelerated microglial M2 polarization, enhanced the phagocytic function of microglial cells, and restrained inflammation in ICH mice. CONCLUSIONS: Overall, our findings suggest that Fer-1 may be a novel mechanism underlying microglial M2 polarization and inflammation after ICH.

tsRNA-GlyGCC promotes colorectal cancer progression and 5-FU resistance by regulating SPIB.

BACKGROUND: tRNA-derived small RNAs (tsRNAs) are newly discovered non-coding RNA, which are generated from tRNAs and are reported to participate in several biological processes in diseases, especially cancer; however, the mechanism of tsRNA involvement in colorectal cancer (CRC) and 5-fluorouracil (5-FU) is still unclear. METHODS: RNA sequencing was performed to identify differential expression of tsRNAs in CRC tissues. CCK8, colony formation, transwell assays, and tumor sphere assays were used to investigate the role of tsRNA-GlyGCC in 5-FU resistance in CRC. TargetScan and miRanda were used to identify the target genes of tsRNA-GlyGCC. Biotin pull-down, RNA pull-down, luciferase assay, ChIP, and western blotting were used to explore the underlying molecular mechanisms of action of tsRNA-GlyGCC. The MeRIP assay was used to investigate the N(7)-methylguanosine RNA modification of tsRNA-GlyGCC. RESULTS: In this study, we uncovered the feature of tsRNAs in human CRC tissues and confirmed a specific 5' half tRNA, 5'tiRNA-Gly-GCC (tsRNA-GlyGCC), which is upregulated in CRC tissues and modulated by METTL1-mediated N(7)-methylguanosine tRNA modification. In vitro and in vivo experiments revealed the oncogenic role of tsRNA-GlyGCC in 5-FU drug resistance in CRC. Remarkably, our results showed that tsRNA-GlyGCC modulated the JAK1/STAT6 signaling pathway by targeting SPIB. Poly (ß-amino esters) were synthesized to assist the delivery of 5-FU and tsRNA-GlyGCC inhibitor, which effectively inhibited tumor growth and enhanced CRC sensitive to 5-FU without obvious adverse effects in subcutaneous tumor. CONCLUSIONS: Our study revealed a specific tsRNA-GlyGCC-engaged pathway in CRC progression. Targeting tsRNA-GlyGCC in combination with 5-FU may provide a promising nanotherapeutic strategy for the treatment of 5-FU-resistance CRC.

Qijia rougan formula ameliorates ECM deposition in hepatic fibrosis by regulating the JAK1/STAT6-microRNA-23a feedback loop in macrophage M2 polarization.

Hepatic fibrosis is the critical pathological stage in the progression of chronic liver disease to cirrhosis and hepatocellular carcinoma (HCC). However, no approved anti-hepatic fibrosis drugs are available currently. Qijia Rougan Formula (QRF) is a traditional Chinese medicine (TCM) with significant clinical efficacy on hepatic fibrosis. It was derived from Sanjiasan, a famous decoction documented in the Book of Treatise on the Pestilence in the Ming Dynasty of China. However, the underlying regulatory mechanisms remain elusive. This study further confirmed the therapeutic effects of QRF on hepatic fibrosis and dissected its underlying molecular mechanisms from the perspective of macrophage M2 polarization, one of the critical events in hepatic fibrosis. Experimentally, QRF significantly improved extracellular matrix (ECM) deposition and fibrosis in the liver of model rats. QRF diminished the proportion of M2 macrophages, decreased the levels of TGF-ß, PDGFB and IL-10, and regulated the expression of p-JAK1, p-STAT6, JAK1 and microRNA-23a both in vitro and in vivo. Collectively, it was confirmed that QRF effectively improves liver function and hepatocyte damage, and reduces ECM deposition. QRF ameliorates hepatic fibrosis by regulating JAK1/STAT6-microRNA-23a negative feedback loop to inhibit macrophage M2 polarization and thus reduce ECM deposition. Our study illustrates the potential of QRF for hepatic fibrosis therapy, suggesting that QRF is a promising anti-hepatic fibrosis drug candidate.

Aerobic Vaginitis Induced by Escherichia coli Infection During Pregnancy Can Result in Adverse Pregnancy Outcomes Through the IL-4/JAK-1/STAT-6 Pathway.

Aerobic vaginitis (AV) can occur if normal vaginal microflora are dominated by aerobic bacteria, seriously affects not only female health, but also fetal health while they are pregnant. Besides, pregnant status also aggravates the symptoms and consequences of the infection. Here, we infected pregnant BALB/c mice with Escherichia coli on embryonic day 4.5 (E4.5) (study group), and administered an equivalent volume of phosphate-buffered saline in another cohort of pregnant mice (control group). We recorded the weight of pregnant mice and their fetuses. The maternal and fetal weight of the study group decreased in comparison with that of the control group, whereas the weight of placenta increased in the study group. Then, five genes with significant upregulation and 15 genes with downregulation were screened. Expression of interleukin 4 (IL-4) mRNA in the study group decreased to 18.5%. Enzyme-linked immunosorbent assay results showed IL-4 expression in mouse plasma declined in the study group at E11.5 and E18.5. mRNA expression of chemokine (c-c motif) ligand (CCL)-17, CCL-22, CCL-24, IL-4, Janus Kinase (JAK)-1, signal transducer and activator of transcription (STAT)-6, and GATA-3 showed significant downregulation in placental and uterine tissues. Flow cytometry of primary decidual macrophages (DMs) revealed more M1-like macrophages in the study group. And after addition of IL-4 to DMs, more M1 macrophages polarized to M2 type macrophages. We did not discover bacteria existed in mouse placentas. Our study affords a feasible method for exploring and managing AV during pregnancy.

IL-4 Switches Microglia/macrophage M1/M2 Polarization and Alleviates Neurological Damage by Modulating the JAK1/STAT6 Pathway Following ICH.

Inflammatory damage following ICH is often attributed to microglia/macrophage activation. In many diseases, IL-4 has been proven to switch microglia/macrophages from the pro-inflammatory to the anti-inflammatory subtype. However, the role and underlying mechanism of IL-4 in ICH, especially in neuroprotection, remain unknown. In our study, we constructed a microglia/macrophage polarization model in BV2 cells to verify that the M2 shift of microglia/macrophages was mediated by JAK1/STAT6 after IL-4 treatment and then revealed that in vitro administration of IL-4 decreased M1 markers, pro-inflammatory cytokines and neuroapoptosis markers but significantly increased M2 markers and anti-inflammatory cytokines. Using an ICH model in mice, we observed that IL-4 administration decreased neurological deficits, brain edema and infarct lesions induced by ICH. We verified that IL-4 mediates inflammation by regulating M1/M2 polarization in ICH and explored the underlying mechanism. Furthermore, we discovered that pathway components and apoptosis-related proteins showed consistent trends based on their respective roles, and inferred that the process that TNF-α activates caspase-3 may be the crosstalk that microglia phagocytosis developed into accelerate apoptosis of cells in ICH. In conclusion, our study demonstrates that IL-4 may promote M2 microglia/macrophage polarization partly through the JAK1/STAT6 pathway to alleviate neuroinflammation after ICH.