Mycophenolic Acid Predose Concentrations and Renal Function in a Mouse Model for Progressive Renal Fibrosis

Cyclosporine A but Not Corticosteroids Support Efficacy of Ex Vivo Expanded, Adoptively Transferred Human Tregs in GvHD

Reshaping the immune balance by adoptive transfer of regulatory T-cells (Tregs) has emerged as a promising strategy to combat undesired immune reactions, including in Graft-versus-Host Disease (GvHD), which is the most lethal non-relapse complication of allogeneic hematopoietic stem cell transplantation. Currently however, little is known about the potentially inhibitory in vivo effects of conventional immunosuppressive drugs, which are routinely used to treat GvHD, on adoptively transferred Tregs. Here we demonstrate drug-specific effects of the conventional immunosuppressive drugs Cyclosporine A, Mycophenolate mofetil and methylprednisolone on adoptively transferred Tregs in a humanized NOD/SCID/IL2Rgamma-/- GvHD mouse model. The clinical course of GvHD and postmortem organ histology, including cellular organ infiltration, showed that co-administration of Cyclosporine A and Tregs is highly beneficial as it enhanced Treg accumulation at inflammatory sites like lung and liver. Similarly, co-administration of Mycophenolate mofetil and Tregs improved clinical signs of GvHD. In contrast, co-administration of methylprednisolone and Tregs resulted in reduced Treg recruitment to inflammatory sites and the fast deterioration of some animals. Consequently, when clinical trials investigating safety and efficacy of adjunctive Treg therapy in GvHD are designed, we suggest co-administering Cyclosporine A, whereas high doses of glucocorticosteroids should be avoided.

Suppression of Hepatocellular Carcinoma by Mycophenolic Acid in Experimental Models and in Patients

BACKGROUND

Tumor recurrence is a major complication following liver transplantation (LT) as treatment for hepatocellular carcinoma (HCC). Immunosuppression is an important risk factor for HCC recurrence, but conceivably may depend on the type of immunosuppressive medication. Mycophenolic acid (MPA) is a currently widely used immunosuppressant. This study investigated the effects of MPA on HCC.

METHODS

Three human HCC cell lines and organoids from mouse primary liver tumor were used as experimental models. MTT, Alamar Blue assay, cell cycle analysis, colony formation, and [3H]-thymidine assays were performed. An LT database was used for retrospective analysis of the effect of mycophenolate mofetil, the prodrug of MPA, on HCC recurrence.

RESULTS

With clinically achievable concentrations, MPA effectively inhibited HCC cell proliferation and single-cell colony-forming unit. In short-term experiments, MPA effectively elicited S phase arrest in HCC cell lines. In addition, the initiation and growth of liver tumor organoids were effectively inhibited by MPA. Most importantly, the use of mycophenolate mofetil in patients with HCC-related LT was significantly associated with less tumor recurrence and improved patient survival.

CONCLUSIONS

MPA can specifically counteract HCC growth in vitro and tumor recurrence in LT patients. These results warrant prospective clinical trials into the role of MPA-mediated immunosuppression following LT of patients with HCC.

Effects of mycophenolate mofetil on kidney function and phosphorylation status of renal proteins in Alport COL4A3-deficient mice

Background

We investigated the effects of mycophenolate mofetil (MMF) on kidney function and on protein phosphorylation in a mouse model for the human Alport syndrome.

Methods

COL4A3-deficient (COL4A3−/−) mice were randomly allocated to receive a placebo (PLC COL4A3−/−) or MMF treatment (MMF COL4A3−/−). Wild type mice (WT) were used as controls. Changes in serum creatinine, total protein and blood urea nitrogen (BUN), concentrations of mycophenolic acid (MPA) and its glucuronide metabolite (MPAG), serum protein electrophoresis, urine dipstick chemistry and sediment were measured. Changes in the phosphorylation status of renal proteins and histology were analyzed.

Results

MMF influenced kidney function and protein phosphorylation. Serum creatinine and BUN were lower in MMF treated compared to PLC treated COL4A3−/− mice. Serum albumin and alpha-1 globulins were significantly decreased while serum creatinine, alpha-2 globulins, urine dipstick protein, leukocyte esterase, hemoglobin and red blood cells were all increased in both COL4A3−/− groups compared to WT. Differential 2DE-gel analysis identified six phosphorylated kidney protein spots that were significantly altered by MMF.

Conclusions

These data suggest that the MMF treatment in this murine model moderately improved kidney function and reversed the phosphorylation status of six renal phosphoprotein spots to that seen in WT mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-014-0056-z) contains supplementary material, which is available to authorized users.

Mycophenolic acid augments interferon-stimulated gene expression and inhibits hepatitis C Virus infection in vitro and in vivo

Mycophenolic acid (MPA) is a highly effective immunosuppressant that has broad antiviral activity against different viruses and can act in synergy with interferon-α (IFN-α) on hepatitis C virus (HCV) replication. MPA is a potent inosine monophosphate dehydrogenase (IMPDH) inhibitor but the antiviral mechanisms are less understood. The aim of this study was to investigate the inhibition of HCV infection by MPA and the molecular basis for its synergy with IFN-α. The role of IMPDH and interferon-stimulated genes (ISGs) was investigated in two HCV models using gain- or loss-of-function approaches. The in vivo effect of MPA treatment was studied in NOD/SCID mice engrafted with HCV replicon cells. Potent antiviral effects of MPA at clinically relevant concentrations were observed with both the subgenomic and JFH1-derived infectious HCV models. MPA treatment in mice resulted in a specific and robust inhibition of HCV replication. Ectopic expression of an MPA-resistant IMPDH2 mutant in HCV host cells completely reversed the antiproliferative effect of MPA but only partially affected the antiviral potency. However, similar to ribavirin, MPA induced expression of multiple antiviral ISGs, including interferon regulatory factor 1 (IRF1). Cotreatment of MPA with IFN-α resulted in additive effects on ISG expression and enhanced IFN-induced luciferase reporter activity. Knockdown of IRF1, but not IFITM3, significantly attenuated the inhibition of HCV replication by MPA.

CONCLUSION

MPA exerts a potent anti-HCV effect in vitro and in mice and acts in synergy with IFN-α. MPA's antiviral activity partially depends on IMPDH but also involves stimulation of ISGs, providing a molecular basis for its synergy with IFN-α.

Factors increasing quantitative interstitial fibrosis from 0 hr to 1 year in living kidney transplant patients receiving tacrolimus

BACKGROUND

This study investigated the increase in interstitial fibrosis (IF) from 0 hr to 1 month and 1 year posttransplantation in biopsy sections and assessed the risk of developing IF in 118 living kidney recipients.

METHODS

A quantitative analysis of IF was performed using computer-assisted imaging. The percent IF (%IF) in the cortical region at 0 hr was defined as the baseline, and the increases in %IF at 1 month and 1 year were calculated. Demographics, higher (regimen 1) and lower (regimen 2) target trough concentrations of tacrolimus, and the cytochrome P450 (CYP) 3A5 polymorphism were tested as risk factors.

RESULTS

The mean %IF at 0 hr, 1 month, and 1 year was 10.3%+/-4.2%, 15.0%+/-5.8%, and 19.0%+/-7.7%, respectively. %IF increased 1.7- and 2.2-fold from 0 hr to 1 month and 1 year posttransplantation, respectively. At 1 year, the increase was higher in patients with the CYP3A5*3/*3 genotype (nonexpressers), those treated with regimen 1, and those with a lower estimated glomerular filtration rate and higher body mass index. In a multivariate analysis, CYP3A5 nonexpression correlated with the development of IF (odds ratio 2.63, P=0.018). Tacrolimus blood levels in the early stage posttransplantation were higher in nonexpressers than CYP3A5 expressers in both regimens 1 and 2, despite therapeutic drug monitoring.

CONCLUSIONS

The higher concentrations of tacrolimus, especially in the nonexpressers treated with regimen 1, might influence the development of IF. This study suggested that a new regimen with lower and narrow target trough levels of tacrolimus or a dosing strategy based on the CYP3A5 genotype is needed to reduce the risk of developing IF.