BM-MSCs display altered gene expression profiles in B-cell acute lymphoblastic leukemia niches and exert pro-proliferative effects via overexpression of IFI6.

BACKGROUND: The tumor microenvironment (TME) is a supportive environment responsible for promoting the growth and proliferation of tumor cells. Current studies have revealed that the bone marrow mesenchymal stem cells (BM-MSCs), a type of crucial stromal cells in the TME, can promote the malignant progression of tumors. However, in the adult B-cell acute lymphoblastic leukemia (B-ALL) microenvironment, it is still uncertain what changes in BM-MSCs are induced by leukemia cells. METHODS: In this study, we mimicked the leukemia microenvironment by constructing a BM-MSC-leukemia cell co-culture system. In vitro cell experiments, in vivo mouse model experiments, lentiviral transfection and transcriptome sequencing analysis were used to investigate the possible change of BM-MSCs in the leukemia niche and the potential factors in BM-MSCs that promote the progression of leukemia. RESULTS: In the leukemia niche, the leukemia cells reduced the MSCs' capacity to differentiate towards adipogenic and osteogenic subtypes, which also promoted the senescence and cell cycle arrest of the MSCs. Meanwhile, compared to the mono-cultured MSCs, the gene expression profiles of MSCs in the leukemia niche changed significantly. These differential genes were enriched for cell cycle, cell differentiation, DNA replication, as well as some tumor-promoting biofunctions including protein phosphorylation, cell migration and angiogenesis. Further, interferon alpha-inducible protein 6 (IFI6), as a gene activated by interferon, was highly expressed in leukemia niche MSCs. The leukemia cell multiplication was facilitated evidently by IFI6 both in vitro and in vivo. Mechanistically, IFI6 might promote leukemia cell proliferation by stimulating SDF-1/CXCR4 axis, which leads to the initiation of downstream ERK signaling pathway. As suggested by further RNA sequencing analysis, the high IFI6 level in MSCs somewhat influenced the gene expression profile and biological functions of leukemia cells. CONCLUSIONS: BM-MSCs in the leukemia niche have varying degrees of changes in biological characteristics and gene expression profiles. Overexpression of IFI6 in BM-MSCs could be a key factor in promoting the proliferation of B-ALL cells, and this effect might be exerted through the SDF-1/CXCR4/ERK signal stimulation. Targeting IFI6 or related signaling pathways might be an important measure to reduce the leukemia cell proliferation.

Mesenchymal Stem Cells With Cancer-Associated Fibroblast-Like Phenotype Stimulate SDF-1/CXCR4 Axis to Enhance the Growth and Invasion of B-Cell Acute Lymphoblastic Leukemia Cells Through Cell-to-Cell Communication.

Background: Bone marrow mesenchymal stem cells (BM-MSCs) are the stromal cells in the leukemia microenvironment, and can obtain cancer-associated fibroblast (CAF)-like phenotype under certain conditions to further promote leukemia progression. However, the mechanism of MSCs with CAF-like phenotype interacting with leukemia cells in B-cell acute lymphoblastic leukemia (B-ALL) and promoting the progression of B-ALL remains unclear. Methods: Mesenchymal stem cells with CAF-like phenotype were obtained by treating MSCs with recombinant human transforming growth factor-ß (rhTGF-ß), hereafter referred to as TGF-ß conditioned MSCs. In vivo mouse model experiments, in vitro transwell chamber experiments, three-dimensional (3D) cell culture models, lentiviral transfection and other experimental methods were used to investigate the possible mechanism of the interaction between TGF-ß conditioned MSCs and leukemia cells in promoting the growth, migration and invasion of B-ALL cells. Results: Compared with untreated MSCs, TGF-ß conditioned MSCs significantly promoted the growth and proliferation of leukemia cells in mice, and increased the expression of CXCR4 in tumor tissues. In vitro cell experiments, TGF-ß conditioned MSCs obviously promoted the migration and invasion of Nalm-6/RS4;11 cells, which were effectively blocked by the CXCR4 inhibitor AMD3100, thereby inhibiting the secretion of MMP-9 in TGF-ß conditioned MSCs and inhibiting the activation of the PI3K/AKT signaling pathway in leukemia cells. Further, findings were made that the interaction between TGF-ß conditioned MSCs and leukemia cells were mediated by the interaction between the integrin receptor α5ß1 on the surface of leukemia cells and the increased expression of fibronectin on TGF-ß conditioned MSCs. AMD3100 could weaken such effect by reducing the expression of integrin α5ß1 on leukemia cells. Further regulation of integrin ß1 could effectively interfere with the interaction between TGF-ß conditioned MSCs and leukemia cells. Conclusion: Mesenchymal stem cells with CAF-like phenotype could be a key factor in promoting the growth and invasion of B-ALL cells, and the SDF-1/CXCR4 axis might be a significant factor in mediating the communication of MSCs with CAF-like phenotype and leukemia cells. To prevent the progression of B-ALL cells, blocking the SDF-1/CXCR4 axis with AMD3100 or targeting integrin ß1 might be a potential therapeutic strategy.

RNA Synthesis by DNA Methyltransferase 1 siRNA Transfection with Cationic Liposomes into Osteoblastic Progenitor Cells Based on SiO² Nanomagnetic Beads for Proliferation and Differentiation.

DNA methylation regulated gene expression is important for osteoblast proliferation and differentiation during bone remodeling and its deregulation leads to the development of osteoporosis. DNA methyltransferase 1 (DNMT1) is an important regulator of DNA methylation. To explore the effect and mechanism of differential expression of DNMT1 in osteoblast precursor cells, DNMT1 siRNAs were designed and synthesized to interfere with DNMT1 expression in the osteoblast precursor cells, MC3T3E1 (Clone 24; MC3T3E1-24). The expression of the target gene, DNMT1, and osteogenic differentiation indicators osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting (WB). MTT assay was used to detect the effect on cell proliferation. Alkaline phosphatase (ALP) activity and alizarin red staining were used to detect the effect of DNMT1 on osteogenic differentiation. Hematoxylin and eosin (H&E) staining was used to detect the morphological changes in MC3T3E1-24 cells. Twenty-four hours following the transfection of MC3T3E1-24 cells with DNMT1 siRNA using cationic liposomes, DNMT1 mRNA and protein levels decreased significantly (P <0.001 for both). The reduced expression of DNMT1 promoted the OPG mRNA and protein expression (P <0.05), increased the ratio of OPG to RANKL (P <0.05), inhibited the expression of RANKL (P <0.01) without affecting the RANKL gene expression (not significant, P >0.05). The reduced expression of DNMT1 also promoted the proliferation of osteoblast precursor cells. In addition, ALP activity test and alizarin red staining showed that reduced expression of DNMT1 resulted in an increase in OPG/RANKL ratio and promoted the differentiation of the precursor cells. The cultured cells were found to have fibroblast-like appearance, and calcium nodules were observed after 7 days of conventional culture. In addition, to improve the efficiency of RNA extraction and save time, a type of silica nanomagnetic beads was used in the early stage of this study to extract RNA and assist qPCR detection of the target genes. The results showed that the magnetic beads could effectively extract RNA from the cells. In conclusion, low expression of DNMT1 affects proliferation and maturation of osteoblasts by upregulating OPG and OPG/RANKL ratio.

CXCL16 deficiency attenuates diabetic nephropathy through decreasing oxidative stress and inflammation.

Soluble C-X-C chemokine ligand 16 (CXCL16) is related to the inflammatory response in liver injury and involved in the pathogenesis of renal dysfunction in diabetes patients. However, the exact role of elevated CXCL16 in diabetic nephropathy (DN) remains unclear. In this study, we investigated the role of CXCL16 in streptozcin (STZ)-induced diabetic nephropathy (DN) in mice. The results showed that fasting blood glucose (FBG) and 24 h urinary protein, triglyceride, and cholesterol levels increased in diabetic mice, and these changes were partially ameliorated in CXCL16 KO mice. Meanwhile, the results also showed that ROS generation was suppressed and the expression levels of inflammatory factors and infiltration factors were inhibited both in vivo and in vitro using DN models. In addition, the total AKT protein and p-AKT levels were decreased in CXCL16-depleted HK-2 cells that were treated with LPS. These findings suggest that the CXCL16 gene product promotes inflammatory factors and cell infiltration factors, and inhibits the expression of antioxidant factors to accelerate the development of DN, and CXCL16 deficiency attenuates DN may be involved in the AKT signaling pathway.

Characterization, pharmacokinetics and tissue distribution of chlorogenic acid-loaded self-microemulsifying drug delivery system.

The purpose of this study was to develop a self-microemulsifying drug delivery system (SMEDDS) to improve the oral bioavailability of Chlorogenic acid (CA), an important bioactive compound from Lonicerae Japonicae Flos with poor permeability. SMEDDS was prepared and characterized by self-emulsifying rate, morphological observation, droplet size determination, stability, in vitro release, in vivo bioavailability and tissue distribution experiments. Results shown that the SMEDDS of CA has a high self-emulsifying rate (>98%) in the dissolution media, and its microemulsion exhibits small droplet size (16.37nm) and good stability. In vitro release test showed a complete release of CA from SMEDDS in 480min. After oral administration in mice, significantly enhanced bioavailability of CA was achieved through SMEDDS (249.4% relative to the CA suspension). Interestingly, SMEDDS significantly changed the tissue distribution of CA and showed a better targeting property to the kidney (2.79 of the relative intake efficiency). It is suggested that SMEDDS improves the oral bioavailability of CA may mainly through increasing its absorption and slowing the metabolism of absorbed CA via changing its distribution from the liver to the kidney. In conclusion, it is indicated that SMEDDS is a promising carrier for the oral delivery of CA.

[Short- and medium-term effectivenesses of stemless hip arthroplasty for treating hip joint disease in young and middle-aged patients].

OBJECTIVE: To summarize the short- and medium-term effectivenesses of stemless hip arthroplasty for treating hip joint disease in young and middle-aged patients. METHODS: Between June 2005 and December 2010, 25 cases (27 hips) of hip joint disease were treated with stemless hip arthroplasty. There were 17 males (19 hips) and 8 females (8 hips) with an average age of 45.6 years (range, 30-57 years), including 13 left hips, 10 right hips, and 2 bilateral hips. The causes included avascular necrosis of the femoral head (ANFH) secondary to femoral neck fracture in 5 cases (5 hips), ANFH in 15 cases (16 hips), osteoarthritis of the hip joint caused by ankylosing spondylitis in 2 cases (3 hips), osteoarthritis of the hip joint caused by dysplasia of acetabular in 2 cases (2 hips), and rheumatoid arthritis in 1 case (1 hip). The disease duration was 1-17 years (mean, 6.1 years). Before operation, the Harris score was 47.6 ± 14.2. RESULTS: The incision healed by first intention in all patients, and no complications occurred, such as infection, periprosthetic fracture, and deep vein thrombosis of lower extremity. Twenty-five patients (27 hips) were followed up 36-96 months (mean, 51 months). One case (1 hip) had sciatic nerve injury after operation, which was relieved by symptomatic treatment. One case (1 hip) had prosthesis loosening, which was relieved after revision. The survival rate of prosthesis was 96.3% (26/27). At last follow-up, the Harris score was 92.1 ± 3.6, which was significantly better than preoperative score (t = 18.241, P = 0.000). The excellent and good rate was 88.9% (excellent in 19 hips, good in 5 hips, fair in 2 hips, and poor in 1 hip). The X-ray films showed good location of prosthesis, and no evidence of dislocation, bone resorption, osteolysis, and heterotopic ossification. CONCLUSION: Because of reserving femoral neck, biomechanics conduction and distribute of the proximal femur achieve natural biomechanics state of the human body. The short- and medium-term effectivenesses of stemless hip arthroplasty for treating hip joint disease in young and middle-aged patients are satisfactory, but the long-term effectiveness need further observation.