GAS6 From CD200+ Adipose-Derived Stem Cells Mitigates Colonic Inflammation in a Macrophage-Dependent Manner

Distinct adaptive immune receptor feature of adipose-derived mesenchymal stem cells (AD-MSCs) treatment of psoriasis

Psoriasis (Ps) is one of the most common chronic inflammatory skin disorders with its pathogenesis correlated with dysregulated innate and adaptive system. Even though biological agents have advanced the treatment of psoriasis, however, there are huge limitations, like high adverse reactions and relapse rate. Therefore, it is of great interest in searching clinical resolutions with better safety and efficacy. In the current study, we utilized the adipose-derived mesenchymal stem cell (AD-MSCs) to treat moderate/severe cases of psoriasis in a single-arm clinical study. This AD-MSC treatment has proven to be clinically safe and effective. Interestingly, a trend of adaptome improvement, including increased diversity, elevated uCDR3s and decreased large clone after AD-MSC treatment in a short (2 weeks) and long (12 weeks) terms. In conclusion, allogenic AD-MSC treatment has shown a good safety and efficacy in treating Ps and can effectively improve the compromised adaptive immune system of Ps patients.

High-throughput omics technologies in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, relapsing intestinal disease. Elucidation of the pathogenic mechanisms of IBD requires high-throughput technologies (HTTs) to effectively obtain and analyze large amounts of data. Recently, HTTs have been widely used in IBD, including genomics, transcriptomics, proteomics, microbiomics, metabolomics and single-cell sequencing. When combined with endoscopy, the application of these technologies can provide an in-depth understanding on the alterations of intestinal microbe diversity and abundance, the abnormalities of signaling pathway-mediated immune responses and functionality, and the evaluation of therapeutic effects, improving the accuracy of early diagnosis and treatment of IBD. This review comprehensively summarizes the development and advancement of HTTs, and also highlights the challenges and future directions of these technologies in IBD research. Although HTTs have made striking breakthrough in IBD, more standardized methods and large-scale dataset processing are still needed to achieve the goal of personalized medicine.

Activation of the CD200/CD200R1 axis improves cognitive impairment by enhancing hippocampal neurogenesis via suppression of M1 microglial polarization and neuroinflammation in hypoxic-ischemic neonatal rats

Following hypoxic-ischemic brain damage (HIBD), there is a decline in cognitive function; however, there are no effective treatment strategies for this condition in neonates. This study aimed to evaluate the role of the cluster of differentiation 200 (CD200)/CD200R1 axis in cognitive function following HIBD using an established model of HIBD in postnatal day 7 rats. Western blotting analysis was conducted to evaluate the protein expression levels of CD200, CD200R1, proteins associated with the PI3K/Akt-NF-κB pathway, and inflammatory factors such as TNF-α, IL-1β, and IL-6 in the hippocampus. Additionally, double-immunofluorescence labeling was utilized to evaluate M1 microglial polarization and neurogenesis in the hippocampus. To assess the learning and memory function of the experimental rats, the Morris water maze (MWM) test was conducted. HIBDleads to a decrease in the expression of CD200 and CD200R1 proteins in the neonatal rat hippocampus, while simultaneously increasing the expression of TNF-α, IL-6, and IL-1β proteins, ultimately resulting in cognitive impairment. The administration of CD200Fc, a fusion protein of CD200, was found to enhance the expression of p-PI3K and p-Akt, but reduce the expression of p-NF-κB. Additionally, CD200Fc inhibited M1 polarization of microglia, reduced neuroinflammation, improved hippocampal neurogenesis, and mitigated cognitive impairment caused by HIBD in neonatal rats. In contrast, blocking the interaction between CD200 and CD200R1 with the anti-CD200R1 antibody (CD200R1 Ab) exerted the opposite effect. Furthermore, the PI3K specific activator, 740Y-P, significantly increased the expression of p-PI3K and p-Akt, but reduced p-NF-κB expression. It also inhibited M1 polarization of microglia, reduced neuroinflammation, and improved hippocampal neurogenesis and cognitive function in neonatal rats with HIBD. Our findings illustrate that activation of the CD200/CD200R1 axis inhibits the NF-κB-mediated M1 polarization of microglia to improve HIBD-induced cognitive impairment and hippocampal neurogenesis disorder via the PI3K/Akt signaling pathway.

GAS5 promotes cytarabine induced myelosuppression via inhibition of hematopoietic stem cell differentiation

Cytarabine (Ara-C) is widely used in the induction chemotherapy for acute myeloid leukemia (AML). Association between LncRNA GAS5 genetic polymorphism and the recovery of hematopoietic function after Ara-C-based chemotherapy is observed. This study aimed to identify whether intervention of GAS5 expression and GAS5 genotype affect Ara-C-induced inhibition of hematopoietic stem cells (HSCs) differentiation. In this study, cord blood-derived CD34+ cells were cultured in vitro, and a cell model of myelosuppression was established by treatment of CD34+ cells with Ara-C. The effect of GAS5 overexpression, Ara-C treatment, and GAS5 rs55829688 genotype on the hematopoietic colony-forming ability of CD34+ cells was assessed using methylcellulose-based colony forming unit assay. GAS5 overexpression slowed down the proliferation of cord blood-derived CD34+ cells significantly (p < 0.05) and decreased their ability to form hematopoietic colonies in vitro. Ara-C significantly reduced the hematopoietic colony-forming ability of CD34+ cells in vitro (p < 0.0001), and overexpressing GAS5 further decreased the number of hematopoietic colonies. GAS5 expression was higher in CD34+ cells than in CD34- cells, and positively correlated with GATA1 mRNA expression in CD34+ cells in vitro culture. However, GAS5 genotype had no effect on the total number of hematopoietic colonies formed from cord blood-derived CD34+ cells. In conclusion, our study highlights that GAS5 inhibited the in vitro proliferation and reduced the hematopoietic colony-forming ability of cord blood-derived CD34+ cells, with the most pronounced effect observed on CFU-GEMM formation. GAS5 also enhanced the inhibitory effect of Ara-C on the in vitro hematopoietic ability of CD34+ HSCs.

Ginseng-derived nanoparticles alleviate inflammatory bowel disease via the TLR4/MAPK and p62/Nrf2/Keap1 pathways

Inflammatory bowel disease (IBD) is closely linked to the homeostasis of the intestinal environment, and exosomes can be used to treat IBD due to their high biocompatibility and ability to be effectively absorbed by the intestinal tract. However, Ginseng-derived nanoparticles (GDNPs) have not been studied in this context and their mechanism of action remains unclear. Here, we investigated GDNPs ability to mediate intercellular communication in a complex inflammatory microenvironment in order to treat IBD. We found that GDNPs scavenge reactive oxygen species from immune cells and intestinal epithelial cells, inhibit the expression of pro-inflammatory factors, promote the proliferation and differentiation of intestinal stem cells, as well as enhancing the diversity of the intestinal flora. GDNPs significantly stabilise the intestinal barrier thereby promoting tissue repair. Overall, we proved that GDNPs can ameliorate inflammation and oxidative stress in vivo and in vitro, acting on the TLR4/MAPK and p62/Keap1/Nrf2 pathways, and exerting an anti-inflammatory and antioxidant effect. GDNPs mitigated IBD in mice by reducing inflammatory factors and improving the intestinal environment. This study offers new evidence of the potential therapeutic effects of GDNPs in the context of IBD, providing the conceptual ground for an alternative therapeutic strategy.

Macrophage polarization in inflammatory bowel disease

The growing prevalence of inflammatory bowel disease (IBD) has encouraged research efforts, which have contributed to gradual improvements in our understanding of IBD diagnosis and therapeutic approaches. The pathogenesis of IBD has not been fully elucidated; however, the combined actions of environmental, genetic, immune factors, and microbial organisms are believed to cause IBD. In the innate immune system, macrophages play important roles in maintaining intestinal health and in the development of IBD. Macrophages can be polarized from M0 into several phenotypes, among which M1 and M2 play critical roles in IBD development and the repair of intestinal homeostasis and damage. Certain macrophage-related IBD studies already exist; however, the functions of each phenotype have not been fully elucidated. As technology develops, understanding the link between macrophages and IBD has increased, including the growing knowledge of the developmental origins of intestinal macrophages and their performance of comprehensive functions. This review describes macrophage polarization in IBD from the perspectives of macrophage development and polarization, macrophage changes in homeostasis and IBD, metabolic changes, and the mechanisms of macrophage polarization in IBD. The discussion of these topics provides new insights into immunotherapy strategies for IBD. Video Abstract.

Activation of the CD200/CD200R1 axis attenuates neuroinflammation and improves postoperative cognitive dysfunction via the PI3K/Akt/NF-κB signaling pathway in aged mice

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a neurological complication occurring after anesthesia and surgery. Neuroinflammation plays a critical role in the pathogenesis of POCD, and the activation of the cluster of differentiation 200 (CD200)/CD200R1 axis improves neurological recovery in various neurological disorders by modulating inflammation. The aim of this study was to investigate the impact and underlying mechanism of CD200/CD200R1 axis on POCD in aged mice.

METHODS

The model of POCD was established in aged mice. To assess the learning and memory abilities of model mice, the Morris water maze test was implemented. CD200Fc (CD200 fusion protein), CD200R1 Ab (anti-CD200R1 antibody), and 740Y-P (a specific PI3K activator) were used to evaluate the effects of the CD200/CD200R1/PI3K/Akt/NF-κB signaling pathway on hippocampal microglial polarization, neuroinflammation, synaptic activity, and cognition in mice.

RESULTS

It was observed that anesthesia/surgery induced cognitive decline in aged mice, increased the levels of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1 β and decreased the levels of postsynaptic density protein 95 (PSD-95), synaptophysin (SYN) in the hippocampus. Moreover, CD200Fc and 740Y-P attenuated neuroinflammation and synaptic deficits and reversed cognitive impairment via the phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (Akt)/nuclear factor-kappa B (NF-κB) signaling pathway, whereas CD200R1 Ab administration exerted the opposite effects. Our results further show that the CD200/CD200R1 axis modulates M1/M2 polarization in hippocampal microglia via the PI3K/Akt/NF-κB signaling pathway.

CONCLUSIONS

Our findings indicate that the activation of the CD200/CD200R1 axis reduces neuroinflammation, synaptic deficits, and cognitive impairment in the hippocampus of aged mice by regulating microglial M1/M2 polarization via the PI3K/Akt/NF-κB signaling pathway.