Antiviral response within different cell types of the CNS.

The central nervous system (CNS) is a constitutive structure of various cell types conserved by anatomical barriers. Many of the major CNS cell-type populations distributed across the different brain regions are targets for several neurotropic viruses. Numerous studies have demonstrated that viral susceptibility within the CNS is not absolute and initiates a cell-type specific antiviral defence response. Neurons, astrocytes, and microglial cells are among the major resident cell populations within the CNS and are all equipped to sense viral infection and induce a relative antiviral response mostly through type I IFN production, however, not all these cell types adopt a similar antiviral strategy. Rising evidence has suggested a diversity regarding IFN production and responsiveness based on the cell type/sub type, regional distinction and cell`s developmental state which could shape distinct antiviral signatures. Among CNS resident cell types, neurons are of the highest priority to defend against the invading virus due to their poor renewable nature. Therefore, infected and uninfected glial cells tend to play more dominant antiviral roles during a viral infection and have been found to be the major CNS IFN producers. Alternatively, neuronal cells do play an active part during antiviral responses but may adopt differential strategies in addition to induction of a typical type I IFN response, to minimize the chance of cellular damage. Heterogeneity observed in neuronal IFN responsiveness may be partially explained by their altered ISGs and/or lower STATS expression levels, however, further in vivo studies are required to fully elucidate the specificity of the acquired antiviral responses by distinct CNS cell types.

Anti-Inflammatory Effect of Combined Sitagliptin and Vitamin D3 on Cytokines Profile in Patients with Type 2 Diabetes Mellitus.

Studies indicated that imbalance of proinflammatory and anti-inflammatory cytokines may contribute to development of type 2 diabetes mellitus (T2DM). We hypothesized that sitagliptin and VitD3 may exert more anti-inflammatory effects on the regulation of cytokine balance in T2DM. Nonnephropathic and nephropathic T2DM patients were divided into the subgroups, based on treatments. The effect of 8 months sitagliptin, alone or together with 2 months of VitD3, on serum IFN-γ, IL-4, IL-17, IL-6, IL-21, TGF-ß, and IL-37 levels was determined using enzyme-linked immunosorbent assay. Increased levels of interferon (IFN)-γ and IL-17 in untreated (without sitagliptin and VitD3) nephropathic and nonnephropathic patients and decreased levels of IL-37 in untreated nephropathic patients were observed compared with healthy controls. Treatment with sitagliptin plus VitD3 reduced the levels of IFN-γ and IL-17 in both nonnephropathic and nephropathic patients compared with untreated patients. The level of IL-37 was enhanced in patients treated with sitagliptin or sitagliptin plus VitD3, compared with untreated patients. Sitagliptin plus VitD3 treatment increased the levels of IL-4 in nonnephropathic patients. These findings indicated that the sitagliptin plus VitD3 was more effective to reduce the increased proinflammatory IFN-γ and IL-17 cytokines in T2DM patients.

Effects of sitagliptin and vitamin D3 on T helper cell transcription factors and cytokine production in clinical subgroups of type 2 diabetes mellitus: highlights upregulation of FOXP3 and IL-37.

Objective: Gene expression level of T helper cell transcription factors and cytokines production in type-2 diabetes mellitus (T2DM) patients treated with mono- or combined sitagliptin and vitamin D3 (VitD3) were evaluated. Methods: Fifty-four nephropathic and 57 non-nephropathic T2DM patients were divided into the subgroups based on their treatment with/without sitagliptin and VitD3. The expression of T-bet, RORγt, BCL6, and FOXP3 was evaluated using real-time PCR. The levels of IFN-γ, IL-6, IL-17, IL-21, TGF-ß, and IL-37 were assessed in PBMC supernatants using ELISA. Results: The production of IFN-γ and IL-17 was increased in untreated (without sitagliptin and VitD3) nephropathic and non-nephropathic T2DM patients compared with healthy controls, whereas FOXP3 expression was decreased. Treatment with sitagliptin alone or in combination with VitD3 reduced the production of IFN-γ in the patients. Production of IL-17 and IL-21 and the expression of RORγt and BCL6 was diminished in patients treated with combined sitagliptin and VitD3, whereas the production of IL-37 and FOXP3 expression were increased in the patients treated with sitagliptin or sitagliptin plus VitD3. Conclusion: These data demonstrate that sitagliptin in combination with VitD3 may accelerate the process of T2DM treatment by exerting synergic anti-inflammatory effects on immune system through upregulation of FOXP3 and IL-37, and downregulation of RORγt and BCL6 as well as IFN-γ, IL-17 and IL-21 production. Combined sitagliptin and VitD3 can be safely utilized to modulate the inflammatory conditions of T2DM.