Hypothalamic Hnscr regulates glucose balance by mediating central inflammation and insulin signal.

OBJECTIVES: Hypothalamic dysfunction leads to glucose metabolic imbalance; however, the mechanisms still need clarification. Our current study was to explore the role of hypothalamic Hnscr in glucose metabolism. MATERIALS AND METHODS: Using Hnscr knockout or htNSC-specific Hnscr overexpression mice, we evaluated the effects of Hnscr on glucose metabolism through GTTs, ITTs, serum indicator measurements, etc. Immunofluorescence staining and Western blotting were performed to test inflammation levels and insulin signalling in hypothalamus. Conditioned medium intervene were used to investigate the effects of htNSCs on neuronal cell line. We also detected the glucose metabolism of mice with htNSCs implantation. RESULTS: Hnscr expression decreased in the hypothalamus after high-fat diet feed. Hnscr-null mice displayed aggravated systematic insulin resistance, while mice with htNSC-specific Hnscr overexpression had the opposite phenotype. Notably, Hnscr-null mice had increased NF-κB signal in htNSCs, along with enhanced inflammation and damaged insulin signal in neurons located in arcuate nucleus of hypothalamus. The secretions, including sEVs, of Hnscr-deficient htNSCs mediated the detrimental effects on the CNS cell line. Locally implantation with Hnscr-depleted htNSCs disrupted glucose homeostasis. CONCLUSIONS: This study demonstrated that decreased Hnscr in htNSCs led to systematic glucose imbalance through activating NF-κB signal and dampening insulin signal in hypothalamic neurons.

A mechanosensitive lipolytic factor in the bone marrow promotes osteogenesis and lymphopoiesis.

Exercise can prevent osteoporosis and improve immune function, but the mechanism remains unclear. Here, we show that exercise promotes reticulocalbin-2 secretion from the bone marrow macrophages to initiate bone marrow fat lipolysis. Given the crucial role of lipolysis in exercise-stimulated osteogenesis and lymphopoiesis, these findings suggest that reticulocalbin-2 is a pivotal regulator of a local adipose-osteogenic/immune axis. Mechanistically, reticulocalbin-2 binds to a functional receptor complex, which is composed of neuronilin-2 and integrin beta-1, to activate a cAMP-PKA signaling pathway that mobilizes bone marrow fat via lipolysis to fuel the differentiation and function of mesenchymal and hematopoietic stem cells. Notably, the administration of recombinant reticulocalbin-2 in tail-suspended and old mice remarkably decreases bone marrow fat accumulation and promotes osteogenesis and lymphopoiesis. These findings identify reticulocalbin-2 as a novel mechanosensitive lipolytic factor in maintaining energy homeostasis in bone resident cells, and it provides a promising target for skeletal and immune health.

Alkbh1-mediated DNA N6-methyladenine modification regulates bone marrow mesenchymal stem cell fate during skeletal aging.

OBJECTIVES: DNA N6-methyladenine (N6-mA) demethylase Alkbh1 participates in regulating osteogenic differentiation of mesenchymal stem cell (MSCs) and vascular calcification. However, the role of Alkbh1 in bone metabolism remains unclear. MATERIALS AND METHODS: Bone marrow mesenchymal stem cells (BMSCs)-specific Alkbh1 knockout mice were used to investigate the role of Alkbh1 in bone metabolism. Western blot, qRT-PCR, and immunofluorescent staining were used to evaluate the expression of Alkbh1 or optineurin (optn). Micro-CT, histomorphometric analysis, and calcein double-labeling assay were used to evaluate bone phenotypes. Cell staining and qRT-PCR were used to evaluate the osteogenic or adipogenic differentiation of BMSCs. Dot blotting was used to detect the level of N6-mA in genomic DNA. Chromatin immunoprecipitation (Chip) assays were used to identify critical targets of Alkbh1. Alkbh1 adeno-associated virus was used to overexpress Alkbh1 in aged mice. RESULTS: Alkbh1 expression in BMSCs declined during aging. Knockout of Alkbh1 promoted adipogenic differentiation of BMSCs while inhibited osteogenic differentiation. BMSC-specific Alkbh1 knockout mice exhibited reduced bone mass and increased marrow adiposity. Mechanistically, we identified optn as the downstream target through which Alkbh1-mediated DNA m6A modification regulated BMSCs fate. Overexpression of Alkbh1 attenuated bone loss and marrow fat accumulation in aged mice. CONCLUSIONS: Our findings demonstrated that Alkbh1 regulated BMSCs fate and bone-fat balance during skeletal aging and provided a potential target for the treatment of osteoporosis.

Scara3 regulates bone marrow mesenchymal stem cell fate switch between osteoblasts and adipocytes by promoting Foxo1.

OBJECTIVES: Scavenger receptor class A, member 3 (Scara3) was involved in adipogenesis. However, the effect of Scara3 on the switch between osteogenesis and adipogenesis of bone marrow mesenchymal stem cells (BMSCs) remains elusive. MATERIALS AND METHODS: The correlations between SCARA3 with the osteogenic-related were analysed based on the GTEx database. The effects of Scara3 on osteogenic or adipogenic differentiation of BMSCs were evaluated by qPCR, Western blot (WB) and cell staining. The mechanisms of Scara3 regulating Foxo1 and autophagy were validated by co-expression analysis, WB and immunofluorescence. In vivo, Scara3 adeno-associated virus was injected into intra-bone marrow of the aged mice and ovariectomized (OVX) mice whose phenotypes were confirmed by micro-CT, calcein double labelling and immunochemistry (HE and OCN staining). RESULTS: SCARA3 was positively correlated with osteogenic-related genes. Scara3 expression gradually decreased during adipogenesis but increased during osteogenesis. Moreover, the deletion of Scara3 favoured adipogenesis over osteogenesis, whereas overexpression of Scara3 significantly enhanced the osteogenesis at the expense of adipogenesis. Mechanistically, Scara3 controlled the cell fate by promoting Foxo1 expression and autophagy flux. In vivo, Scara3 promoted bone formation and reduced bone marrow fat accumulation in OVX mice. In the aged mice, Scara3 overexpression alleviated bone loss as well. CONCLUSIONS: This study suggested that Scara3 regulated the switch between adipocyte and osteoblast differentiation, which represented a potential therapeutic target for bone loss and osteoporosis.

ASPH Regulates Osteogenic Differentiation and Cellular Senescence of BMSCs.

Osteogenesis and senescence of BMSCs play great roles in age-related bone loss. However, the causes of these dysfunctions remain unclear. In this study, we identified a differentially expressed ASPH gene in middle-aged and elderly aged groups which were obtained from GSE35955. Subsequent analysis in various databases, such as TCGA, GTEx, and CCLE, revealed that ASPH had positive correlations with several osteogenic markers. The depletion of mouse Asph suppressed the capacity of osteogenic differentiation in bone marrow mesenchymal stem cells (BMSCs). Notably, the expression of ASPH in vitro decreased during aging and senescence. The deficiency of Asph accelerated cellular senescence in BMSCs. Conversely, the overexpression of Asph enhanced the capacity of osteogenic differentiation and inhibited cellular senescence. Mechanistically, ASPH regulated Wnt signaling mediated by Gsk3ß. Taken together, our data established that ASPH was potentially involved in the pathogenesis of age-related bone loss through regulating cellular senescence and osteogenic differentiation, which provides some new insights to treat age-related bone loss.

Ophiopogonin D promotes bone regeneration by stimulating CD31hi EMCNhi vessel formation.

OBJECTIVES: CD31hi EMCNhi vessels (CD31, also known as PECAM1 [platelet and endothelial cell adhesion molecule 1]; EMCN, endomucin), which are strongly positive for CD31 and endomucin, couple angiogenesis and osteogenesis. However, the role of CD31hi EMCNhi vessels in bone regeneration remains unknown. In the present study, we investigated the role of CD31hi EMCNhi vessels in the process of bone regeneration. MATERIALS AND METHODS: We used endothelial-specific Krüppel like factor 3 (Klf3) knockout mice and ophiopogonin D treatment to interfere with CD31hi EMCNhi vessel formation. We constructed a bone regeneration model by surgical ablation of the trabecular bone. Immunofluorescence and micro-computed tomography (CT) were used to detect CD31hi EMCNhi vessels and bone formation. RESULTS: CD31hi EMCNhi vessels participate in the process of bone regeneration, such that endothelial-specific Klf3 knockout mice showed increased CD31hi EMCNhi vessels and osteoprogenitors in the bone regeneration area, and further accelerated bone formation. We also demonstrated that the natural compound, ophiopogonin D, acts as a KLF3 inhibitor to promote vessels formation both in vitro and in vivo. Administration of ophiopogonin D increased the abundance of CD31hi Emcnhi vessels and accelerated bone healing. CONCLUSIONS: Our findings confirmed the important role of CD31hi Emcnhi vessels in bone regeneration and provided a new target to treat bone fracture or promote bone regeneration.

miR­483­3p regulates osteogenic differentiation of bone marrow mesenchymal stem cells by targeting STAT1.

Osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) is regulated by a variety of intracellular regulatory factors including osterix, runt­related transcription factor 2 (RUNX2), bone morphogenetic proteins and transforming growth factorß. Recent studies have shown that microRNAs (miRs) serve a crucial role in this process. In the present study, miR­483­3p levels were significantly increased during osteogenic differentiation of mouse and human BMSCs. Overexpression of miR­483­3p promoted osteogenic differentiation, whereas inhibition of miR­483­3p reversed these effects. miR­483­3p regulated osteogenic differentiation of BMSCs by targeting STAT1, and thus enhancing RUNX2 transcriptional activity and RUNX2 nuclear translocation. In vivo, overexpression of miR­483­3p using a BMSC­specific aptamer delivery system stimulated bone formation in aged mice. Therefore, the present study suggested that miR­483­3p promoted osteogenic differentiation of BMSCs by targeting STAT1, and miR­483­3 prepresent a potential therapeutic target for age­related bone loss.

Krüppel-like factor 3 inhibition by mutated lncRNA Reg1cp results in human high bone mass syndrome.

High bone mass (HBM) is usually caused by gene mutations, and its mechanism remains unclear. In the present study, we identified a novel mutation in the long noncoding RNA Reg1cp that is associated with HBM. Subsequent analysis in 1,465 Chinese subjects revealed that heterozygous Reg1cp individuals had higher bone density compared with subjects with WT Reg1cp Mutant Reg1cp increased the formation of the CD31hiEmcnhi endothelium in the bone marrow, which stimulated angiogenesis during osteogenesis. Mechanistically, mutant Reg1cp directly binds to Krüppel-like factor 3 (KLF3) to inhibit its activity. Mice depleted of Klf3 in endothelial cells showed a high abundance of CD31hiEmcnhi vessels and increased bone mass. Notably, we identified a natural compound, Ophiopogonin D, which functions as a KLF3 inhibitor. Administration of Ophiopogonin D increased the abundance of CD31hiEmcnhi vessels and bone formation. Our findings revealed a specific mutation in lncRNA Reg1cp that is involved in the pathogenesis of HBM and provides a new target to treat osteoporosis.

MiR-497∼195 cluster regulates angiogenesis during coupling with osteogenesis by maintaining endothelial Notch and HIF-1α activity.

A specific bone vessel subtype, strongly positive for CD31 and endomucin (CD31hiEmcnhi), is identified as coupling angiogenesis and osteogenesis. The abundance of type CD31hiEmcnhi vessels decrease during ageing. Here we show that expression of the miR-497∼195 cluster is high in CD31hiEmcnhi endothelium but gradually decreases during ageing. Mice with depletion of miR-497∼195 in endothelial cells show fewer CD31hiEmcnhi vessels and lower bone mass. Conversely, transgenic overexpression of miR-497∼195 in murine endothelium alleviates age-related reduction of type CD31hiEmcnhi vessels and bone loss. miR-497∼195 cluster maintains the endothelial Notch activity and HIF-1α stability via targeting F-box and WD-40 domain protein (Fbxw7) and Prolyl 4-hydroxylase possessing a transmembrane domain (P4HTM) respectively. Notably, endothelialium-specific activation of miR-195 by intravenous injection of aptamer-agomiR-195 stimulates CD31hiEmcnhi vessel and bone formation in aged mice. Together, our study indicates that miR-497∼195 regulates angiogenesis coupled with osteogenesis and may represent a potential therapeutic target for age-related osteoporosis.

GDF8 inhibits bone formation and promotes bone resorption in mice.

Growth Differentiation Factor 8 (GDF8), also called myostatin, is a member of the transforming growth factor (TGF)-ß super-family. As a negative regulator of skeletal muscle growth, GDF8 is also associated with bone metabolism. However, the function of GDF8 in bone metabolism is not fully understood. Our study aimed to investigate the role of GDF8 in bone metabolism, both in vitro and in vivo. Our results showed that GDF8 had a negative regulatory effect on primary mouse osteoblasts, and promoted receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis in vitro. Intraperitoneal injection of recombinant GDF8 repressed bone formation and accelerated bone resorption in mice. Furthermore, treatment of aged mice with a GDF8 neutralizing antibody stimulated new bone formation and prevented bone resorption. Thus, our study showed that GDF8 plays a significant regulatory role in bone formation and bone resorption, thus providing a potential therapeutic pathway for osteoporosis.

GDF11 Inhibits Bone Formation by Activating Smad2/3 in Bone Marrow Mesenchymal Stem Cells.

Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor-ß superfamily. Recent studies confirmed that GDF11 plays an important role in regulating the regeneration of brain, skeletal muscle, and heart during aging; however, its role in bone metabolism remains unclear. Thus, the aim of this study was to determine the effects of GDF11 on bone metabolism, including bone formation and bone resorption, both in vitro and in vivo. Our results showed that GDF11 inhibited osteoblastic differentiation of bone marrow mesenchymal stem cells in vitro. Mechanistically, GDF11 repressed Runx2 expression by inducing SMAD2/3 phosphorylation during osteoblast differentiation. Moreover, intraperitoneal injection of GDF11 inhibited bone formation and accelerated age-related bone loss in mice. Our results also showed that GDF11 had no effect on osteoclast differentiation or bone resorption both in vitro and in vivo. These results provide a further rationale for the therapeutic targeting of GDF11 for the treatment of age-related osteoporosis.

A novel microRNA regulates osteoclast differentiation via targeting protein inhibitor of activated STAT3 (PIAS3).

MicroRNAs (miRNAs) involve in the regulation of a wide range of physiological processes. Recent studies suggested that miRNAs might play a role in osteoclast differentiation. Here, we identify a new miRNA (miR-9718) in primary mouse osteoclasts that promotes osteoclast differentiation by repressing protein inhibitor of activated STAT3 (PIAS3) at the post-transcriptional level. MiR-9718 was found to be transcribed during osteoclastogenesis, which was induced by macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL). Overexpression of miR-9718 in RAW 264.7 cells promoted M-CSF and RANKL-induced osteoclastogenesis, whereas inhibition of miR-9718 attenuated it. PIAS3 was predicted to be a target of miR-9718. Luciferase reporter gene validated the prediction. Transfection of pre-miR-9718 in RAW 264.7 cells induced by both M-CSF and RANKL inhibited expression of PIAS3 protein, while the mRNA levels of PIAS3 were not attenuated. In vivo, our study showed that silencing of miR-9718 using a specific antagomir inhibited bone resorption and increased bone mass in mice receiving ovariectomy (OVX) and in sham-operated control mice. Thus, our study showed that miR-9718 played an important role in osteoclast differentiation via targeting PIAS3 both in vitro and in vivo.

MiR-125a TNF receptor-associated factor 6 to inhibit osteoclastogenesis.

MicroRNAs (miRNAs) play important roles in osteoclastogenesis and bone resorption. In the present study, we found that miR-125a was dramatically down-regulated during macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL) induced osteoclastogenesis of circulating CD14+ peripheral blood mononuclear cells (PBMCs). Overexpression of miR-125a in CD14+ PBMCs inhibited osteoclastogenesis, while inhibition of miR-125a promoted osteoclastogenesis. TNF receptor-associated factor 6 (TRAF6), a transduction factor for RANKL/RANK/NFATc1 signal, was confirmed to be a target of miR-125a. EMSA and ChIP assays confirmed that NFATc1 bound to the promoter of the miR-125a. Overexpression of NFATc1 inhibited miR-125a transcription, and block of NFATc1 expression attenuated RANKL-regulated miR-125a transcription. Here, we reported that miR-125a played a biological function in osteoclastogenesis through a novel TRAF6/ NFATc1/miR-125a regulatory feedback loop. It suggests that regulation of miR-125a expression may be a potential strategy for ameliorating metabolic disease.

Relationships between serum omentin-1 concentration and bone mineral density, and bone biochemical markers in Chinese women.

BACKGROUND: Omentin-1, as a newly discovered adipocytokine, plays an important role in bone metabolism. However, the association between circulating omentin-1 level and bone mineral density (BMD) in Chinese women has never been investigated. METHODS: Serum omentin-1, adiponectin, leptin, bone turnover biochemical markers, BMD were determined in 225 premenopausal women and 285 postmenopausal women. RESULTS: In premenopausal Chinese women, omentin-1 level was significantly higher compared to postmenopausal women. The multiple linear stepwise regression analysis showed that lean mass, omentin-1 and weight were independent predictors of BMD in premenopausal women. Omentin-1 was negatively correlated with bone-specific alkaline phosphatase (BAP) and bone cross-linked N-terminal telopeptides of type I collagen (NTX) in premenopausal women. However the omentin-1 was not the predictor of BMD in postmenopausal women. CONCLUSIONS: Omentin-1 is an independent predictor of BMD in premenopausal Chinese women, and shows a negative correlation with bone turnover biochemical markers. Our results suggest that omentin-1 may exert a negative effect on bone mass by inhibiting bone formation in premenopausal women.

KCNQ1 gene polymorphisms are associated with the therapeutic efficacy of repaglinide in Chinese type 2 diabetic patients.

The present study evaluated the effects of KCNQ1 rs2237892 and rs2237895 polymorphisms on repaglinide efficacy in Chinese patients with type 2 diabetes mellitus (T2DM). In all, 367 T2DM patients and 214 controls were genotyped. Forty of the T2DM patients were randomly selected to undergo 8 weeks repaglinide treatment. The frequency of the rs2237892 allele was lower in the T2DM patients than in the control group (P < 0.05). The frequency of the rs2237895 C allele was higher in T2DM patients than in healthy control subjects (P < 0.05). Diabetic patients with the rs2237892 risk C allele had lower fasting insulin levels (P < 0.01) and homeostasis model assessment of insulin resistance (HOMA-IR; P < 0.01) values than carriers of the T allele. Diabetic patients with the rs2237895 risk C allele had higher fasting plasma glucose (P < 0.01), postprandial plasma glucose (PPG) levels (P < 0.01) and HOMA-IR values (P < 0.01) than those with the A allele. Following repaglinide treatment, those T2DM patients with the rs2237892 T allele and rs2237895 C allele were more likely to have a positive response to repaglinide in terms of PPG levels (P < 0.05) than T2DM patients with the rs2237892 CC and rs2237895 AA genotypes. In conclusion, KCNQ1 rs2237892 and rs2237895 polymorphisms were found to be associated with the therapeutic efficacy of repaglinide in Chinese T2DM patients.

[Oral administration of insulin inhibits islet beta cell apoptosis and prevents diabetes in NOD mice].

OBJECTIVE: To investigate the effect of oral administration of insulin on insulitis beta cell apoptosis and diabetes in non-obese diabetic (NOD) mice, and to explore the mechanism of immune tolerance induced by insulin. METHODS: Eighty-six female NOD mice were randomly divided into an insulin group (n=43) and a phosphate buffered saline (PBS) group (n=43). From 4 weeks of age, the recombinant human insulin (Humulin R) 1 mg (70 microL) was administrated in the oral insulin group and 70 microL PBS in the control group respectively, twice per week before 12 weeks of age and then once weekly until 30 weeks. Insulitis and beta cell apoptosis of islets were observed at 12 weeks. IL-4 and IFN-gamma in the sera were measured by enzyme linked immunosorbent assay (ELISA). The expression levels of I-Abeta(g7), IL-4, IFN-gamma, IL-1beta, Fas and TGF-beta mRNA of islets, and IL-4, IFN-gamma, TGF-beta mRNA of Peyer's patch were measured by reverse transcription-polymerase chain reaction (RT-PCR) at 12 weeks. RESULTS: The incidences in the insulin group were significantly lower than those in the PBS group (55.6% vs 85.7% at 30 weeks, 70.4% vs 96.4% at 52 weeks, P<0.05). The insulitis scores in the insulin group were lower than those in the PBS group, but there was no statistical significance. Fas expression on islets and apoptotic beta cell rates in the insulin group were lower than those in the PBS group (P<0.05). In the insulin group, serum IL-4 levels were higher, and IFN-gamma levels were lower than those in the PBS group (P<0.05). The levels of I-Abeta(g7), IFN-gamma, IL-1beta and Fas mRNA transcription in islets and IFN-gamma mRNA transcription in Peyer's patch were both lower in the insulin group, and IL-4, TGF-beta mRNA levels were higher than those in the PBS group (P<0.05). CONCLUSION: The specific autoantigen insulin may induce the immune tolerance and prevent the diabetes in NOD mice, but it cannot block the progression of insulitis. Oral administration of insulin can induce the regulatory T cells, and make Th1 to Th2 cytokine shifts in the system and islets, thus preventing the Fas-mediated beta-cell apoptosis and diabetes.

[Inhibition of islet beta cell apoptosis and prevention diabetes by subcutaneous administration of insulin in NOD mice].

OBJECTIVE: To investigate the effects of subcutaneous administration of insulin on insulitis,beta cell apoptosis and diabetes in non-obese diabetic (NOD) mice, and to explore the mechanism of immune tolerance induced by insulin. METHODS: Sixty female NOD mice were randomly divided into insulin group (n=32) and phosphate buffered saline (PBS) group (PBS group, n=28). Insulin was subcutaneously injected with humulin N (60 microL, 6U)+IFA (60 microL) at 4, 12, 20, and 28 weeks respectively, while the PBS group received PBS (60 microL) + IFA (60 microL). Insulitis and beta cell apoptosis of islets were observed at 12 weeks. IL-4 and IFN-gamma in the sera were measured by enzyme linked immunosorbent assay (ELISA). The expression levels of I-Abeta(g7), IL-4, IFN-gamma, IL-1beta, and Fas mRNA of islets were measured by reverse transcription-polymerase chain reaction (RT-PCR) at 12 weeks. RESULTS: The incidences in the insulin group were significantly lower than those in the PBS group (21.4% vs 71.4% at 30 weeks, 28.6% vs 85.7% at 52 weeks, P<0.05). The insulitis scores in the insulin group were lower than those in the PBS group, but there was no statistical significance. Fas expression on islets and apoptotic beta cell rates in the insulin group were lower than those in the PBS group (P<0.05). In the insulin group, serum IL-4 levels were higher, but IFN-gamma levels were lower than those in the PBS group (P<0.05). The levels of I-Abeta g7, IFN-gamma, IL-1beta and Fas mRNA transcription in islets were lower in insulin group, but IL-4 mRNA levels were higher than those in the PBS group (P<0.05). CONCLUSION: The specific autoantigen insulin may induce immune tolerance and prevent diabetes in NOD mice, but it can't block the progression of insulitis. Subcutaneous administration of insulin can induce the regulatory T cells, and make Th1 to Th2 cytokine shifts in system and islets, thus preventing the Fas-mediated beta-cell apoptosis and diabetes.

[Preventive effects of pioglitazone on diabetes and relevant mechanisms, experimental study on non-obese diabetic mice].

OBJECTIVE: To explore the effects of pioglitazone on insulitis and diabetes and relevant mechanism. METHODS: Seventy-three female non-obese diabetic (NOD)/Lt mice aged 4 weeks were randomly divided into 3 groups, control group (n = 25, fed with regular diet), low dosage pioglitazone group (n = 23, pioglitazone of the concentration of 0.01% was added into the feed) and high dosage pioglitazone group (n = 25, pioglitazone of the concentration of 0.04% was added into the feed). The mice were killed when diabetes developed or they reached the age of 30 weeks. The body weight and amount of food intake were measured every week and the amount of drug intake was calculated. Urine glucose was checked weekly from week 10 to week 30. When urine glucose was positive and relevant symptoms appeared, blood glucose was measured. The criterion of diagnosis of diabetes was the consecutive blood glucose level > or = 16.7 mmol/L for 2 times. At the 12th week 4-7 mice from the 3 groups respectively were killed and their pancreases were removed to be scored on insulitis by HE staining, the spleen cells were cultured. The IL-4 and IFN-r levels in serum and supernatants of spleen cell cultures were measured by ELISA. The pancreatic IFN-r mRNA level was tested using RT-PCR method. RESULTS: (1) At the age of 30 weeks, the diabetes incidence rates was 80% (20/25) in the control group, 60.9% (14/23) in the low dose group, and 60% (15/25) in the high dose group (P > 0.05). At the following time points the diabetes incidence rates of the 2 treated groups were lower than that of the control group (all P < 0.05): (1) 0% in the low dose group vs 16%: of the control group at the age of 100 days, and 39% vs 68% at the age of 185 days; and (2) 0% in the high dose group vs 16% in the control group at the age of 110 days, 4% vs 24% at the age of 120 days, and 12%vs 36% at the age of 135 days. (2) There was no difference in insulitis scores between the control group and low dose or high dose groups at the age of 12 weeks (1.99 +/- 0.75 vs 1.01 +/- 0.68 and 1.19 +/- 0.84, both P > 0.05), however, the score of the combined pioglitazone group (low dose group + high dos group) was significantly higher than that of the control group (1.12 +/- 0.75 vs 1.99 +/- 0.75, P < 0.05). (3) There was no differences in the IL-4/IFN-r ratios in serum and splenocyte culture supernatant and pancreatic IFN-r mRNA levels among the three groups (all P > 0.05). CONCLUSION: Pioglitazone, to some extent, lessens the insulitis severity and delays the diabetes onset. Its mechanism may be unrelated to immune deviation of Th1 to a Th2.

[Mechanisms of human glutamic acid decarboxylase 65 DNA vaccine preventing diabetes in non-obese diabetic mice].

OBJECTIVE: To investigate the mechanisms of human GAD65 DNA vaccine preventing insulitis and diabetes in NOD mice. METHODS: Female NOD mice at 4 weeks of age were randomly divided into PBS (n = 21), pcDNA (n = 20), and hGAD65 (n = 21) groups. Mice in each group received two intramuscular injections of 0.05 ml PBS alone, 50 microg pcDNA3.1 and 50 microg DNA vaccine emulsified in 0.05 ml PBS 7 days apart respectively. The accumulative diabetes incidence was followed-up to 30 weeks of age in each group of NOD mice. Pancreas was removed from NOD mice at 12 weeks of age in each group (n = 10) to score insulitis severity by routine H-E staining. The apoptotic beta cells in islets were observed with double-labeling technique of TUNEL in situ combined standard sensitive avdin-biotin complex (sABC) immunohistochemical method. Their spleens were for cell culture and total RNA extraction. Spleen IL-4, IFN-gamma, NF-ATc and NF-ATp mRNA levels were tested by RT-PCR. IL-4 and IFN-gamma levels in sera and supernatants of spleen cells were measured by ELISA. RESULTS: (1) At 30 weeks of age, the diabetes incidence was 95.2%, 80.0% and 61.9% in PBS, pcDNA and hGAD65 group respectively. The diabetes incidence in the PBS group was higher than that in hGAD65 group (P = 0.008). (2) At 12 weeks of age, the insulitis scores in hGAD65 group was lower than that in PBS group (P = 0.001) and pcDNA group (P = 0.027) respectively. (3) The apoptotic beta cell rates in hGAD65 group was lower than that in PBS group (P = 0.014) and pcDNA group (P = 0.023). (4) IL-4 levels in sera, spleen IL-4 and NF-ATc mRNA level in hGAD65 group were higher than those in PBS group (all P < 0.05) and pcDNA group (all P < 0.05) respectively, NF-ATp mRNA level in hGAD65 group was lower than that in PBS group (P < 0.05). CONCLUSION: Human GAD65 DNA vaccine via downregulating NF-ATp and upregulating NF-ATc and IL-4, makes Th cells deviate to Th2, and sequently prevents insulitis, beta-cell apoptosis and diabetes onset in NOD mice.

[Liposome and complete Freund's adjuvant for the prevention of insulitis in non-obese diabetic mice].

OBJECTIVE: To explore the effects of complete Freund's adjuvant (CFA), incomplete Freund's adjuvant(IFA), large multilamellar liposome (LML) and small cationic liposome (DOTAP) on insulitis and diabetes. METHODS: 1. 3-week-old non-obese diabetic(NOD) female mice were randomly divided into 3 groups: CFA group (injected subcutaneously in the hind footpad, n = 16), IFA group (injected intraperitoneally, n = 16) and PBS group (injected subcutaneously in the hind footpad, n = 16). Three mice from each group (9 in total) were killed at the age of 12 weeks for the analysis of pancreatic pathology, and the others were not killed until they were 30 weeks old for diabetes incidence. 2. 3-week-old NOD female mice were randomly divided into 3 groups and injected intraperitoneally with LML (n = 13), DOTAP (n = 13) and PBS (n = 13), respectively. The insulitis score and diabetes incidence were estimated in the same way. RESULTS: 1. CFA injected subcutaneously in the hind footpad could significantly reduce the insulitis score and decrease diabetes incidence in NOD mice. At the age of 30 weeks, the incidence of diabetes in the CFA group was lower than that in the PBS group (injected subcutaneously in the hind footpad) (9.2% vs 81.8%, P = 0.001). At the age of 12 weeks, the insulitis score in the CFA group was lower than that in the control group [(0.05 +/- 0.02) vs (0.54 +/- 0.11), P < 0.001]. 2. LML injected intraperitoneally could significantly reduce the insulitis score in NOD mice. At the age of 12 weeks, the insulitis score in the LML group was lower than that in the PBS control group (injected intraperitoneally) [(0.16 +/- 0.02) vs (0.58 +/- 0.06), P < 0.001]. At the age of 30 weeks, there were no significant differences in the diabetes incidence between the LML group and the PBS group (60% vs 90%). 3. The protective effect of CFA was better than that of LML in NOD mice. CONCLUSION: CFA injected subcutaneously in the hind footpad may prevent NOD mice from developing diabetes and reduce the insulitis severity. Although the protective effect of CFA is better than that of LML, LML can lessen the insulitis severity and may become a new preventive strategy in NOD mice.