Modulatory effect of interleukin-2 loaded chitosan nano sphere on regulatory T cell activity in streptozotocin-induced diabetic mice.

OBJECTIVE: The current study aimed to assess the modulating effect of IL-2 encapsulated chitosan-nanoparticles (CSNPs) on the function of Treg cells through induction of type 1 diabetes (T1D). Treg cell function was monitored by the forkhead box P3 (FoxP3) and transforming growth factor beta (TGFß) levels, correlating them with blood glucose and serum insulin levels. MATERIALS AND METHODS: In this case-control study, a low dose of IL-2 (free and chitosan-loaded) was injected into a diabetic mice group. The levels of FoxP3 and TGF-ß 1 were assessed using Enzyme-Linked Immunosorbent Assay. In addition, blood glucose and serum insulin levels were determined. RESULTS: The mean glucose level decreased significantly after free rIL-2 or rIL-2 / CSNPs treatment. Meanwhile, the mean serum insulin level was significantly increased after treatment with free rIL-2 or rIL-2/CSNPs. The mean levels of FoxP3 and TGFß 1 were significantly increased with either free rIL-2 or rIL-2/CSNPs compared to the T1D untreated group (P < 0.001). In the treated mice group receiving free CSNPs, there was a significant negative correlation between glucose and insulin levels. Moreover, FoxP3 & TGFß 1 levels had a significant positive correlation. In treated mice groups with free rIL-2 and IL-2 CSNPs, there was a significant positive correlation between FoxP3 and glucose levels. A significant negative correlation was found after conducting a correlation between insulin level and FoxP3 in the T1D/ rIL-2 / CSNPs group. CONCLUSIONS: Low-dose IL-2 selectively modulates FoxP3 + Tregs, and TGFß 1 increases their levels. These results demonstrated that IL-2-free and chitosan-loaded nanoparticles can be therapeutic agents in T1D.

Low-dose interleukin-2-loaded nanoparticle effect on NK and T-reg cell expression in experimentally induced type 1 diabetes mellitus.

INTRODUCTION: Type 1 diabetes mellitus is an autoimmune disorder characterized by inflammatory damage to pancreatic ß cells resulting in loss of insulin secretion. In autoimmune type 1 diabetes mellitus (T1D) natural killer cells (NK) initiate pancreatic islets cell lyses in autoimmune T1D. Loss of T regulatory cells (Treg) at disease onset facilitates the activation and accumulation of NKs in the pancreatic microenvironment. A proper low-dose interleukin 2 (IL-2) could enhance Tregs and enforce control and regulation of pro-inflammatory NKs. AIM: This relation needs to be studied to improve therapeutic strategies aimed at resetting the balance between Tregs and proinflammatory cells. MATERIAL AND METHODS: We used novel formulations of low-dose IL-2 loaded on chitosan nanoparticles. The study included 116 T1D BALB/c mice experimentally induced by streptozotocin, divided into groups. Their splenocytes were maintained in a short-term culture for assessment of expression of CD4+FOXP3+ Treg and NKp46+NK by both flow cytometry and enzyme-linked immunoassay (ELISA). Morphological, immunohistochemical, and morphometrical analyses were done. In vitro suppressor assay was used to assess the suppressor effect of Treg cells after exogenous IL-2 treatment. RESULTS: NK cell expression, NKp46 level, and NK cell functions were modulated more in mice injected with IL-2-loaded chitosan nanoparticles than in other groups. A statistical inverse correlation was found between Treg and NK cell expression in IL-2-loaded chitosan with 0.3 µIU (p = 0.047), and this correlation was related to FOXP3 expression on Treg cells. The modified expression of NK and NKp46 was noticed in mice injected with 0.3 µIU for longer duration (3 weeks) (p < 0.001), but the NK functions did not show any significant changes with prolonged treatment. CONCLUSIONS: Prolonged administration of low-dose IL-2 results in the vigorous expression of NKp46, indicating a significant role of Tregs in NK stimulation and motivation. Low-dose IL-2 selectively modulates NKp46 NK and FOXP3+ Tregs and increases their expression.

Effect of low dose IL-2 loaded chitosan nanoparticles on natural killer and regulatory T cell expression in experimentally induced autoimmune type 1 diabetes mellitus.

INTRODUCTION: Natural killer cells (NK) initiate pancreatic islets cell lyses in autoimmune type 1 diabetes mellitus (T1D). Loss of T regulatory cells (Treg) at disease onset facilitates activation and accumulation of NKs in the pancreatic microenvironment. A proper low dose interleukin 2 (IL-2) could enhance Tregs and enforce control and regulation of pro-inflammatory NKs. This relation needs to be studied to improve therapeutic strategies aimed at resetting the balance between Tregs and proinflammatory cells. MATERIAL AND METHODS: We used novel formulations of low dose IL-2 loaded on chitosan nanoparticles. The study included 116 T1D BALB/c mice experimentally induced by streptozotocin, divided into groups. Their splenocytes were maintained in a short-term culture for assessment of expression of CD4+Foxp3+ Treg and NKp46+NK by both flow cytometry and enzyme linked immunoassay (ELISA). In vitro suppressor-assay was used in order to assess the suppressor effect of Treg cells after exogenous IL-2 treatment. RESULTS: NK cell expression, NKp46 level and NK cell functions were modulated in mice injected with IL-2 loaded chitosan nanoparticles than other groups. A statistical inverse correlation was found between Treg and NK cell expression in IL-2 loaded chitosan with (0.3 µIU) (p = 0.047) and this correlation was related to Foxp3 expression on Treg cells. The modified expression of NK and NKp46 was noticed in mice injected with (0.3 µIU) for longer duration (three weeks) (p < 0.001) but the NK functions did not show any significant changes with prolonged treatment. CONCLUSIONS: Low dose (0.3) µIU IL-2 nanoparticles effectively modulated NK and NKp46 expression. It selectively modulates the suppressive activity of Tregs indicating a significant role of Tregs in NK activation and function by controlling the availability of IL-2 in the microenvironment.

Concanavalin-A as a Model for Induction of Murine Autoimmune Hepatitis: Role of TNF-α and NF-κß During The Acute Phase.

Autoimmune hepatitis (AIH) is a heterogeneous immune-mediated chronic liver disease affecting children and adults. It is important to rely on a specific animal model to study the hepatic changes and to evaluate the roles played by pro-inflammatory cytokines such as tumor necrosis factor alpha "TNF-α" and transcription factors such as nuclear factor kappa-light-chain-enhancer of activated B cells "NF-κß" in the pathogenesis and outcome of the disease. This will help to identify specific targets for treatment of AIH. This study aimed at evaluating Concanavalin-A (Con A) as a model for induction of AIH and assessing splenocytes' TNF-α and hepatocytes' NF-κß levels at comparable durations after induction of hepatitis with Con A to evaluate the relationship between both factors. Materials and methods: A total of 130 outbreed CD1 mice were divided into group (1) which included 100 mice with induced AIH and group (2) included 30 normal mice as negative controls. Intra-peritoneal injection of Concanavalin-A was used to induce hepatitis. Hepatic injury was evaluated by the levels of liver enzymes, histopathological evidence for hepatic inflammatory infiltrate and/or apoptosis. Splenocytes and hepatocytes were cultured for assessment of TNF-α and NF-κß levels, respectively. Results: Con A injection caused a significant elevation in ALT and AST levels, portal inflammatory infiltrate, remarkable hepatocytes degeneration and marked increase of TNF-α levels, particularly within 24 hours, but all returned to normal within 1 week. Administration of another dose of Con A resulted in sharp significant elevation of liver enzymes, inflammatory infiltrate and hepatocyte apoptosis after 24 hours and sustained till the end of the study. There was a significant increase in NF-κß throughout most of the study duration following Con A injection as compared to that of normal mice. In conclusions, intra-peritoneal administration of Con A, particularly two doses, represents an efficient approach for induction of immune-mediated hepatitis. T-cells play a major role in AIH through release of TNF-α. Coincidently, hepatitis seems to be associated with elevation of NF-κß to protect hepatocytes. Thus TNF-α and NF-κß can represent targets for treatment of AIH either through inhibition or augmentation, respectively.