Insulin-producing cells from human adipose tissue-derived mesenchymal stem cells detected by atomic force microscope

Regulating effect of Circ_ATRNL1 on the promotion of SOX9 expression to promote chondrogenic differentiation of hAMSCs mediated by MiR-145-5p

Circ_ATRNL1 is significantly highly expressed in cartilage tissues of patients with osteoarthritis. This study explored the role and mechanism of circ_ATRNL1 in cartilage differentiation of human adipose-derived mesenchymal stem cells (hAMSCs). hAMSCs were isolated and identified by flow cytometry. The degree of chondrocyte and adipogenic differentiation was assessed using Alcian blue staining and Oil Red O staining, respectively. The expressions of cartilage- and adipogenic-related genes, circ_ATRNL1, and SOX9 were detected by reverse transcription quantitative polymerase chain reaction. The correlation between SOX9 and circ_ATRNL1 was analyzed using Pearson test. Bioinformatics and luciferase analysis were used to detect the overlapped target miRNAs of circ_ATRNL1 and SOX9. The role of circ_ATRNL1/miRNA/SOX9 was examined using functional rescue assays. hAMSCs were identified as CD90-, CD105-, and CD44-positive. The degree of cartilage differentiation of hAMSCs was significantly enhanced after 2 weeks. Cartilage-related genes, circ_ATRNL1 and SOX9, were significantly upregulated, and positively correlated with each other. Circ_ATRNL1 overexpression enhanced hAMSC proliferation and differentiation into chondrogenesis, and promoted the expressions of COL2, Aggrecan, and SOX9. Overexpression of circ_ATRNL1 inhibited the adipogenic differentiation of hAMSCs and the expressions of adipogenic-related genes. miR-145-5p was a target miRNA for circ_ATRNL1 and SOX9. miR-145-5p mimic inhibited hAMSC differentiation toward cartilage, and inhibited the expression of cartilage-related factors. miR-145-5p mimic effectively reversed the regulating effect of circ_ATRNL1 on hAMSCs. Circ_ATRNL1 regulates the promotion of SOX9 expression to promote chondrogenic differentiation of hAMSCs mediated by miR-145-5p.

Elucidating nanoscale mechanical properties of diabetic human adipose tissue using atomic force microscopy

Obesity-related type 2 diabetes (DM) is a major public health concern. Adipose tissue metabolic dysfunction, including fibrosis, plays a central role in DM pathogenesis. Obesity is associated with changes in adipose tissue extracellular matrix (ECM), but the impact of these changes on adipose tissue mechanics and their role in metabolic disease is poorly defined. This study utilized atomic force microscopy (AFM) to quantify difference in elasticity between human DM and non-diabetic (NDM) visceral adipose tissue. The mean elastic modulus of DM adipose tissue was twice that of NDM adipose tissue (11.50 kPa vs. 4.48 kPa) to a 95% confidence level, with significant variability in elasticity of DM compared to NDM adipose tissue. Histologic and chemical measures of fibrosis revealed increased hydroxyproline content in DM adipose tissue, but no difference in Sirius Red staining between DM and NDM tissues. These findings support the hypothesis that fibrosis, evidenced by increased elastic modulus, is enhanced in DM adipose tissue, and suggest that measures of tissue mechanics may better resolve disease-specific differences in adipose tissue fibrosis compared with histologic measures. These data demonstrate the power of AFM nanoindentation to probe tissue mechanics, and delineate the impact of metabolic disease on the mechanical properties of adipose tissue.

Mitochondrial ROS activate interleukin-1β expression in allergic rhinitis

Allergic rhinitis (AR) is the most common cause of inflammation of the nasal mucosa. It is also the most common form of non-infectious rhinitis associated with an immunoglobulin E (IgE)-mediated immune response against allergens. Previous studies have indicated that interleukin-1β (IL-1β) has a pathological role in the development of allergic asthma. The present study was designed to assess whether IL-1β participates in the pathogenesis of AR. A total of 45 patients with AR were enrolled in the present study and were identified to have increased IL-1β expression expressed by peripheral blood mononuclear cells (PBMCs), and the mitochondrial reactive oxygen species (ROS) and NLRP3 are required for IL-1β synthesis in monocytes/macrophages and PBMCs from patients with AR. The levels of IL-1β and interleukin-17 (IL-17) were increased in patients with AR and were positively correlated with each other. The results of the present study suggested that patients with AR have raised mitochondrial ROS levels, which may upregulate the expression of IL-1β, affecting IL-17-production and serving a role in the pathogenesis of AR.

Effect of mesenchymal stem cells transplantation on glycaemic profile & their localization in streptozotocin induced diabetic Wistar rats

BACKGROUND & OBJECTIVES

Bone marrow is a rich source of adult stem cells that can differentiate into various cell types. Administration of mesenchymal stem cells (MSCs) in irradiated diabetic rat model has transiently shown to decrease blood glucose level. This study examines the effect of high dose and multiple injections of MSCs on glycemic profile, their localization and regeneration of islet in diabetic Wistar rat.

METHODS

The study was carried out in male Wistar rats categorized into three groups (n=6, in each group): Group 1 as control, group 2 streptozotocin (STZ) (50 mg/kg) induced diabetic group and group 3 experimental group; 5-bromo-2-deoxyuridine (BrdU) labelled allogenic MSCs were injected in the non-irradiated diabetic rat of the experimental group through tail vein. The blood glucose profile was subsequently monitored at regular intervals. Rats were sacrificed on day 45 and pancreas was examined for localization of BrdU labelled stem cells by immunofluorescence and islet-neogenesis by immunohistochemistry .

RESULTS

There was a significant reduction in blood glucose level after administration of MSCs in the experimental group (P<0.001). The presence of BrdU labelled MSCs in islet suggested their localization in the pancreas. Co-expression of anti-BrdU and anti-insulin antibody indicated trans-differentiation / fusion into insulin producing cells evidenced by significant increase in total number of islet (P=0.004) and insulin positive cells ( P<0.0001) in experimental group.

INTERPRETATION & CONCLUSIONS

Our results showed that the MSCs administration in non-irradiated diabetic Wistar rat reduced hyperglycaemia and was accompanied by increased islet-neogenesis, possibly through trans-differentiation/fusion.

Insulin-producing cells could not mimic the physiological regulation of insulin secretion performed by pancreatic beta cells

OBJECTIVE

The aim of this study was to compare the difference between insulin-producing cells (IPCs) and normal human pancreatic beta cells both in physiological function and morphological features in cellular level.

METHODS

The levels of insulin secretion were measured by enzyme-linked immunosorbent assay. The insulin gene expression was determined by real-time quantitative polymerase chain reaction. The morphological features were detected by atomic force microscopy (AFM) and laser confocal scanning microscopy.

RESULTS

IPCs and normal human pancreatic beta cells were similar to each other under the observation in AFM with the porous structure features in the cytoplasm. Both number of membrane particle size and average roughness of normal human beta cells were higher than those of IPCs.

CONCLUSIONS

Our results firstly revealed that the cellular ultrastructure of IPCs was closer to that of normal human pancreatic beta cells, but they still could not mimic the physiological regulation of insulin secretion performed by pancreatic beta cells.