Recombinant adenoviral expression of IL-10 protects beta cell from impairment induced by pro-inflammatory cytokine. Mol Cell Biochem. 2010;344:163-171. [PMID: 20658311 DOI: 10.1007/s11010-010-0539-x]

Gentisic acid ameliorates type 2 diabetes induced by Nicotinamide-Streptozotocin in male mice by attenuating pancreatic oxidative stress and inflammation through modulation of Nrf2 and NF-кB pathways

AIMS

There is a close link between oxidative stress, inflammation, and type 2 diabetes mellitus (T2DM). Gentisic acid (GA) is a di-phenolic compound and an active metabolite of aspirin that possesses antioxidant and anti-inflammatory properties, but its potential anti-diabetic effects have not been evaluated so far. Therefore, this study aimed to evaluate GA's potential antidiabetic effects through the Nuclear Factor Erythroid 2-Related Factor (Nrf2) and Nuclear Factor Kappa Beta (NF-кB) signaling pathways.

MATERIAL AND METHODS

In this study, T2DM induced by a single intraperitoneal injection of STZ (65 mg/kg B.W) after 15 min nicotinamide (120 mg/kg B.W) injection. After seven days of injections, fasting blood glucose (FBS) was measured. Seven days after FBS monitoring treatments started. Grouping and treatments were as follows: 1) Normal control group; NC, 2) Diabetic control group; DC, 3) Metformin group; MT (150 mg/kg B.W, daily), 4) Test group; GA (100 mg/kg B.W, daily). Treatments continued for 14 consecutive days.

KEY FINDINGS

Diabetic mice treatment with GA significantly decreased FBS, improved plasma lipid profiles and pancreatic antioxidant status. GA modulated Nrf2 pathway by upregulation of Nrf2 protein, NAD(P)H: quinone oxidoreductase 1 (Nqo1), and p21, and downregulation of miR-200a, Kelch-like ECH-associated protein 1 (Keap1), and nicotinamide adenine dinucleotide phosphate oxidase-2 (NOX2). Also, GA attenuated inflammation by upregulation of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and interleukin-10 (IL-10) and downregulation of miR-125b, NF-кB, tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1ß).

SIGNIFICANCE

GA attenuates T2DM, possibly by improving antioxidant status through the Nrf2 pathway and attenuation of inflammation.

Effect of IL4 and IL10 on a human in vitro type 1 diabetes model

We defined the effect of the anti-inflammatory cytokines IL4 and IL10 on an in vitro model of human T1D. After preincubation with IL4 or IL10, human islet microtissues were co-cultured with PBMC and proinflammatory cytokines for a few hours or for multiple days to assess acute and chronic effects. This resulted in an immune attack with infiltration of T cells into the islet, a loss of beta cell endocrine function, and an upregulation of HLA-I on the beta cells. HLA-I upregulation was associated with infiltration of T cells and both HLA-I expression and infiltration were associated with impaired insulin secretion. Preincubation with IL4 or IL10 did not preserve beta cell function but decreased infiltration of T cells. Our data support the hypothesis that a loss of beta cell endocrine function mediates an increase in beta cell specific antigen presentation. IL4 and IL10 failed to preserve beta cell endocrine function.

Islet Lymphocytes Maintain a Stable Regulatory Phenotype Under Homeostatic Conditions and Metabolic Stress

T cells and B cells have been identified in human and murine islets, but the phenotype and role of islet lymphocytes is unknown. Resident immune populations set the stage for responses to inflammation in the islets during homeostasis and diabetes. Thus, we sought to identify the phenotype and effector function of islet lymphocytes to better understand their role in normal islets and in islets under metabolic stress. Lymphocytes were located in the islet parenchyma, and were comprised of a mix of naïve, activated, and memory T cell and B cell subsets, with an enrichment for regulatory B cell subsets. Use of a Nur77 reporter indicated that CD8 T cells and B cells both received local antigen stimulus, indicating that they responded to antigens present in the islets. Analysis of effector function showed that islet T cells and B cells produced the regulatory cytokine IL-10. The regulatory phenotype of islet T cells and B cells and their response to local antigenic stimuli remained stable under conditions of metabolic stress in the diet induced obesity (DIO) model. T cells present in human islets retained a similar activated and memory phenotype in non-diabetic and T2D donors. Under steady-state conditions, islet T cells and B cells have a regulatory phenotype, and thus may play a protective role in maintaining tissue homeostasis.

Administration of metrnl delays the onset of diabetes in non-obese diabetic mice

Type 1 diabetes is a chronic metabolic disease characterized by hyperglycemia due to progressive destruction of pancreatic beta cells via autoimmune attack. Meteorin-like protein (metrnl) is a secreted protein homologous to the neurotrophin metrn and it is induced after exercise in the skeletal muscle. In our paper published previously, we showed that the serum level of metrnl was significantly correlated with the lipid profile, glucose profile and insulin resistance. In this experiment, we asked whether intravenous administration of metrnl could delay the onset of diabetes in non-obese diabetic (NOD) mice. 4-week-old NOD mice were injected intravenously with metrnl. Blood glucose levels were measured weekly. Insulitis scoring, intraperitoneal glucose tolerance test, adoptive T cell transfer, flow cytometry analysis and real-time PCR were performed to investigate the underlying mechanism. The results showed that intravenous administration of metrnl delayed the onset of diabetes in NOD mice. Histology of pancreas showed a decreased infiltration of leukocytes, which was in association with augmentation of regulatory T cells, suppression of autoreactive T cells and altered cytokine secretion. To sum up, the present study showed that intravenous administration of metrnl ameliorated islet lymphocyte infiltration and modulated immune cell responses, raising the possibility that it might be beneficial in improving islet function clinically.

EP4 signalling is essential for controlling islet inflammation by causing a shift in macrophage polarization in obesity/type 2 diabetes

Activation of the prostaglandin E₂ receptor EP4 alters polarization of adipose tissue macrophages towards the anti-inflammatory M2 phenotype to suppress chronic inflammation. However, the role of EP4 signalling in pancreatic macrophages that affect insulin secretion is unclear. We examined the role of EP4 signalling in islet inflammation in vitro and in vivo. Obese diabetic db/db mice were treated with an EP4-selective agonist or vehicle for 4 weeks. Islet morphology did not significantly differ and glucose-stimulated insulin secretion was increased, whereas the pancreatic M1/M2 ratio was decreased in the EP4 agonist-treated group compared to the vehicle group. Because EP4 activation in MIN6 cells did not affect insulin secretion, we used a MIN6/macrophage co-culture system to evaluate the role of EP4 signalling in islet inflammation and subsequent inhibition of insulin release. Co-culture with M1-polarized macrophages markedly suppressed insulin expression in MIN6 cells; however, modulation of M1 polarization by the EP4 agonist significantly reversed the negative impact of co-cultivation on insulin production. The enhanced expression levels of pro-inflammatory cytokines in co-cultured MIN6 cells were markedly inhibited by EP4 agonist treatment of M1 macrophages. Thus, EP4 activation may suppress islet inflammation and protect β-cell function by altering inflammatory macrophages in the diabetic pancreas.

Combination therapy with anti-CD20 mAb and IL-10 gene to reverse type 1 diabetes by attenuating pancreatitis and inhibiting apoptosis in NOD mice

AIMS

To assess the combination therapy of anti-CD20 mabs and adenovirus-mediated interleukin-10 (IL-10) gene delivery on the prevention of type 1 diabetes (T1D) in non-obese diabetes (NOD) mice.

MAIN METHODS

In present study, we simultaneously blocked the B cell interactions and recovered the Th cell subset proportion by using through anti-CD20 Mab and adenovirus-mediated gene delivery of IL-10, respectively. After 9 consecutive days of combination therapy, various measurements, including hematoxylin-eosin staining (HE), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling assay (TUNEL), immunohistochemistry, ELISA, PCR and western blot were applied to further assess the efficacy.

KEY FINDINGS

The results suggested that the combination intervention reduced the T1D-associated morbidity of NOD mice, promote insulin secretion, control blood glucose and ease pancreatitis. Moreover, the combination therapy might play a protective role in pancreatic β cells by suppressing the expression of TNF-α and Fas, blocking the Caspase-8 and Caspase-3 apoptotic pathways and activating the Bcl-2 anti-apoptotic pathway. Finally, the combination intervention may up-regulate the gene expression of CK-19 and PDX-1 and further accelerate the differentiation and proliferation of pancreatic β cells.

SIGNIFICANCE

Therefore, the combination intervention with anti-CD20 mabs and the IL-10 gene plays a role in the prevention of T1D to some extent in NOD mice.

Anti-CD20 monoclonal antibody combined with adenovirus vector-mediated IL-10 regulates spleen CD4+/CD8+ T cells and T-bet/GATA-3 expression in NOD mice

Type 1 diabetes (T1D) is an autoimmune disease characterized by a selective destruction of insulin-secreting β-cells. Both T cells and B cells serve a crucial role in pathogenesis and development of T1D. CD20 is a specific membrane antigen of B lymphocytes, while interleukin (IL)‑10 is an important cytokine secreted by T helper 2 cells and has a short half‑life in vivo. The combined effect of anti‑CD20 and IL‑10 on immune function of mice with T1D remains unknown. In the present study, 30 non‑obese diabetic (NOD) mice were treated with anti‑CD20 and adenoviral vector‑mediated interleukin‑10 (Ad‑mIL‑10) therapy. Alterations in CD4+, CD8+, CD4+CD25+Foxp3+ T cells, T‑box expressed in T‑cells (T‑bet), GATA‑binding protein‑3 (GATA‑3) interferon‑γ (IFN‑γ) and IL‑4 were detected by flow cytometry, reverse transcription‑quantitative polymerase chain reaction in NOD mice spleen tissue. The present results suggested that anti‑CD20 and IL‑10 treatment in NOD mice can modulate the immune functions by upregulating GATA‑3 and IL‑4 expression as well as downregulating T‑bet and IFN‑γ expression, which are involved in the pathogenesis of T1D. The current findings may provide a potential method for T1D treatment and a novel preventive therapy for T1D. Combination of anti‑CD20 and Ad‑mIL‑10 treatment had not only immune regulatory effects but also protective effects on islet β‑cells in NOD mice with T1DM at the early stages, by regulating T‑bet/GATA‑3 expression and Th1/Th2 cell differentiation, which has the potential for diabetes prevention and therapy.

Peripheral blood metabolic and inflammatory factors as biomarkers to ocular findings in diabetic macular edema

Aims

To study the association between peripheral blood metabolic and inflammatory factors and presence of diabetic macular edema (DME) and its related anatomic features in type 2 diabetic mellitus (T2DM) patients.

Material and methods

Observational cross-sectional study on a proof of concept basis. Seventy-six T2DM included patients were divided based on the presence (n = 58) or absence of DME (n = 18) according to optical coherence tomography (OCT). Ultra-widefield fluorescein angiography (UWFA) was performed in DME patients. Fasting peripheral blood sample testing included glycemia, glycated hemoglobin, creatinin and lipid levels among others. Serum levels of a broad panel of cytokines and inflammatory mediators were also analysed. OCT findings included central subfoveal thickness, diffuse retinal thickness (DRT), cystoid macular edema (CME), serous retinal detachment and epirretinal membrane. UWFA items included pattern of DME, presence of peripheral retinal ischemia and enlarged foveal avascular zone (FAZ).

Results

Metabolic and inflammatory factors did not statistically differ between groups. However, several inflammatory mediators did associate to certain ocular items of DME cases: IL-6 was significantly higher in patients with DRT (p = 0.044), IL-10 was decreased in patients with CME (p = 0.012), and higher IL-8 (p = 0.031) and VEGF levels (p = 0.031) were observed in patients with enlarged FAZ.

Conclusion

Inflammatory and metabolic peripheral blood factors in T2DM may not be differentially associated to DME when compared to non-DME cases. However, some OCT and UWFA features of DME such as DRT, CME and enlarged FAZ may be associated to certain systemic inflammatory mediators.

STAT3 modulates β-cell cycling in injured mouse pancreas and protects against DNA damage

Partial pancreatic duct ligation (PDL) of mouse pancreas induces a doubling of the β-cell mass mainly through proliferation of pre-existing and newly formed β-cells. The molecular mechanism governing this process is still largely unknown. Given the inflammatory nature of PDL and inflammation-induced signaling via the signal transducer and activator of transcription 3 (STAT3), the activation and the role of STAT3 in PDL-induced β-cell proliferation were investigated. Duct ligation stimulates the expression of several cytokines that can act as ligands inducing STAT3 signaling and phosphorylation in β-cells. β-Cell cycling increased by conditional β-cell-specific Stat3 knockout and decreased by STAT3 activation through administration of interleukin-6. In addition, the level of DNA damage in β-cells of PDL pancreas increased after deletion of Stat3. These data indicate a role for STAT3 in maintaining a steady state in the β-cell, by modulating its cell cycle and protection from DNA damage.

Protective role of adenovirus vector-mediated interleukin-10 gene therapy on endogenous islet β-cells in recent-onset type 1 diabetes in NOD mice

The aim of the present study was to provide an animal experimental basis for the protective effect of the adenoviral vector-mediated interleukin-10 (Ad-mIL-10) gene on islet β-cells during the early stages of type 1 diabetes (T1D) in non-obese diabetic (NOD) mice. A total of 24 female NOD mice at the onset of diabetes were allocated at random into three groups (n=8 per group): Group 1, intraperitoneally injected with 0.1 ml Ad-mIL-10; group 2, intraperitoneally injected with 0.1 ml adenovirus vector; and group 3, was a diabetic control. In addition to groups 1, 2 and 3, 8 age- and gender-matched NOD mice were intraperitoneally injected with 0.1 ml PBS and assigned to group 4 as a normal control. All mice were examined weekly for body weight, urine glucose and blood glucose values prior to onset of diabetes, and at 1, 2 and 3 weeks after that, and all mice were sacrificed 3 weeks after injection. Serum levels of interleukin (IL)-10, interferon (IFN)-γ, IL-4, insulin and C-peptide were evaluated, and in addition the degree of insulitis and the local expression of IL-10 gene in the pancreas were detected. The apoptosis rate of pancreatic β-cells was determined using a TUNEL assay. Compared with groups 2 and 3, IL-10 levels in the serum and pancreas were elevated in group 1. Serum IFN-γ levels were decreased while serum IL-4 levels and IFN-γ/IL-4 ratio were significantly increased in group 1 (P<0.01). C-peptide and insulin levels were higher in group 1 compared with groups 2 and 3, (P<0.01). Furthermore, compared with groups 2 and 3, the degree of insulitis, islet β-cell apoptosis rate and blood glucose values did not change significantly (P>0.05). The administration of the Ad-mIL-10 gene induced limited immune regulatory and protective effects on islet β-cell function in NOD mice with early T1D, while no significant reduction in insulitis, islet β-cell apoptosis rate and blood glucose was observed.

Treadmill training combined with insulin suppresses diabetic nerve pain and cytokines in rat sciatic nerve

BACKGROUND

Insulin therapy plays a critical role in managing type 1 diabetes mellitus, and exercise produces alterations in pain sensation. This experiment explored the effects of insulin therapy combined with treadmill training on diabetic neuropathic pain and on the expression of malondialdehyde (MDA) and cytokines.

METHODS

Rats were given 4 weeks of insulin (100 IU/kg) therapy and treadmill training (30-60 min/d of training at 20-25 m/min) each day beginning on day 3 after streptozotocin (65 mg/kg, IV) injection and continuing until day 27. Sensitivity to heat and mechanical stimuli and the expression of interleukin (IL)-10, IL-6, tumor necrosis factor-α, and MDA in the sciatic nerve were estimated.

RESULTS

We showed that 2 to 4 weeks of treadmill training, insulin treatment, or their combination increased both paw withdrawal thresholds and latencies compared with the same regimen in sedentary diabetic rats (all P < 0.0022). Treatment with insulin, but without treadmill training, had significant effects on glycemic control (P < 0.0001) and restored body weight (P < 0.0001) in the diabetic rats. The diabetic rats demonstrated the upregulation (all P < 0.009) of IL-6, MDA, and tumor necrosis factor-α in the sciatic nerve on days 14 and 28 after streptozotocin treatment, whereas in diabetic rats receiving insulin, treadmill training, or a combination (all P < 0.01), this upregulation was decreased. Insulin, treadmill training, or the combination increased IL-10 expression (all P < 0.0051) in all diabetic rats.

CONCLUSIONS

Treadmill training combined with insulin therapy showed the best improvements in tactile allodynia and thermal hyperalgesia among our 3 treatment groups. The benefits of insulin intervention and treadmill training could be related to chronic inflammation (proinflammatory cytokines) and oxidative stress (MDA).

Study of 27 Aqueous Humor Cytokines in Type 2 Diabetic Patients with or without Macular Edema

The aim of the present study was to compare the changes in the levels of 27 aqueous humor cytokines between diabetic patients with macular edema (ME) and diabetic patients without ME. Undiluted aqueous humor samples were obtained from 68 consecutive type 2 diabetic patients without ME and 56 consecutive type 2 diabetic patients with ME. The concentrations of 27 cytokines in the aqueous humor samples were measured using a multiplex bead immunoassay. Compared with diabetic patients without ME, diabetic patients with ME had significantly higher concentrations of IL-1β, IL-6, IL-8, IP-10, MCP-1, and VEGF in the aqueous humor. However, the concentrations of IL-10 and IL-12 were significantly lower in the diabetic patients with ME. The aqueous humor levels of IL-1β, IL-6, IL-8, MCP-1, IP-10, and VEGF were closely correlated with retinal macular thickness, retinal macular volume and the severity of ME. In addition, the aqueous humor levels of IL-10 and IL-12 decreased with increasing the severity of ME. A variety of cytokines associated with inflammation and angiogenesis may contribute to the pathogenesis of diabetic macular edema, and both anti-inflammatory and antiangiogenic agents should be included in the treatment of ME simultaneously.

Experimental study of local inner ear gene therapy for controlling autoimmune sensorineural hearing loss

This study aimed to investigate the efficacy of gene therapy for treating autoimmune sensorineural hearing loss (ASHL) via local administration of a recombinant adenovirus vector containing the Fas ligand or interleukin IL-10 gene. Guinea pigs were divided into four groups, with different microinjections in the scala tympani. Group A were injected with FasL-EGFP, B with IL-10-EGFP, C with EGFP, and D with artificial perilymph. Seven days later, auditory brain-stem response (ABR) was tested, and the temporal bone was stained and observed by light microscopy. The spiral ligament and basement membrane were observed using transmission electron microscopy. FasL and IL-10 expression were examined using immunofluorescence histochemistry. Immunohistochemical analysis showed that the recombinant adenovirus vector in Groups A, B, and C can transfect the stria vascularis, the spiral ligament, the organ of Corti, the spiral ganglion, the region surrounding the small blood vessel in the modiolus, and the cochlear bone wall. Compared with those in Groups C and D, the ABR wave III mean thresholds were significantly lower and the inner ear immunoinflammatory responses in Groups A and B were significantly alleviated. Inhibition of immunoinflammatory response alleviated immunoinflammatory injury and auditory dysfunction. This technique shows potential as a novel therapy for ASHL.

Protective effects of combined intervention with adenovirus vector mediated IL-10 and IGF-1 genes on endogenous islet β cells in nonobese diabetes mice with onset of type 1 diabetes mellitus

Objective

To investigate the protective effects of combined intervention with adenovirus vector mediated interleukin 10 (IL-10) and insulin-like growth factor 1 (IGF-1) genes on islet β cells in nonobese diabetes (NOD) mice with type 1 diabetes mellitus (T1D) at early stage.

Methods

Twenty-four female NOD mice at onset of diabetes and aged 17–20 weeks old were randomly divided into four groups. Mouse 1, 2 and 3 groups were intraperitoneally injected 0.1 ml of Ad-mIGF-1, Ad-mIL-10, and combined Ad-mIGF-1 and Ad-mIL-10, respectively. Mouse 4 group were used as diabetes control. In addition, six age- and sex-matched non-diabetic NOD mice were intraperitoneally injected 0.1 ml of PBS and assigned 5 group as normal controls. All mice were weekly monitored for body weight, urine glucose and blood glycose, and sacrificed 3 weeks after injection. Their serum levels of IL-10, IGF-1, IFN-γ, IL-4 and C-peptide were measured and the degree of insulitis and the local expression of IGF-1 and IL-10 gene were observed.

Results

1) IL-10 and IGF-1 levels in serum and pancreas were enhanced in 1, 2, and 3 groups; 2) serum INF-γ level was decreased while serum IL-10 and IL-4 levels were increased in 1, 2 and 3 groups, and these alterations were more significant in 3 group than 1 and 2 groups (P<0.01); 3) C-peptide level was not enhanced in 1 group, but significantly increased in 2 and 3 groups, and these increases were more significant in the latter (P<0.01); 4) Three weeks later, the body mass of mice in 2 and 3 groups decreased significantly (P<0.05).

Conclusion

The administration of adenovirus vector mediated IL-10 and/or IGF-1 gene showed limited immune regulatory and protective effects on islet β-cells in NOD mice with T1D at early stage, and no significant reduction in insulitis, blood glucose and body weight.

The impact of anti-inflammatory cytokines on the pancreatic β-cell

Considerable efforts have been invested to understand the mechanisms by which pro-inflammatory cytokines mediate the demise of β-cells in type 1 diabetes but much less attention has been paid to the role of anti-inflammatory cytokines as potential cytoprotective agents in these cells. Despite this, there is increasing evidence that anti-inflammatory molecules such as interleukin (IL)-4, IL-10 and IL-13 can exert a direct influence of β-cell function and viability and that the circulating levels of these cytokines may be reduced in type 1 diabetes. Thus, it seems possible that targeting of anti-inflammatory pathways might offer therapeutic potential in this disease. In the present review, we consider the evidence implicating IL-4, IL-10 and IL-13 as cytoprotective agents in the β-cell and discuss the receptor components and downstream signaling pathways that mediate these effects.

GLP-1 or GLP-1R agonists combined with mesenchymal stem cells protect islet β-cells in patients with type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is the result of autoimmuine-mediated destruction and apoptosis of pancreatic β-cells and dysfunction of pancreatic α-cells to inappropriately secret glucagons to aggravate hyperglycemia. Early induction of immune tolerance, promoting β-cell regeneration and inhibiting the secretion of glucagons by α-cells are therefore the key to the treatment of T1DM. In addition to drug therapy, mesenchymal stem cells (MSCs) are also used to treat T1DM, because they can secret anti-inflammatory and immunomodulatory factors to induce immune tolerance, inhibit T cell proliferation, and repair damaged tissue; and secret several cytokines and biologically active substances to promote β-cell proliferation and differentiation. However, while pancreatic β-cells proliferate after MSC therapy, pancreatic α-cells also show different degrees of proliferation. Glucagon-like peptide 1 (GLP-1) and GLP-1 receptor (GLP-1R) agonists can inhibit the secretion of glucagons by pancreatic α-cells, promote β-cell proliferation and regeneration, inhibit β-cell apoptosis, and induce stem cells to differentiate into insulin-producing cells. Thus, combined use of MSCs with GLP-1 or GLP-1R agonists has synergistic effects in protecting β-cells.