Cyclosporine and tacrolimus: the mainstay of immunosuppressive therapy for solid organ transplantation

Integrative analysis of renal microRNA and mRNA to identify hub genes and pivotal pathways associated with cyclosporine-induced acute kidney injury in mice

Cyclosporine (CsA) is an immunosuppressive agent that often causes acute kidney injury (AKI) in children. The specific mechanisms underlying CsA-induced AKI are currently unknown. This study used an integrated network analysis of microRNA (miRNA) and mRNA expression profiles, biochemical and pathological analyses to further investigate these potential mechanisms of CsA-induced AKI. Small RNA sequence analysis identified 25 differentially expressed miRNAs, RNA sequencing analysis identified 4,109 differentially expressed mRNAs. We obtained a total of 4,367 target genes from the 25 differentially expressed miRNAs based on three algorithms, including the Mirdb, Mirtarbase, and TargetScan. 971 target genes overlapped between the 4,367 target genes and 4,109 differentially expressed mRNAs were identified for further bioinformatics analysis. Finally, 30 hub genes and two main modules were recognized. Functional enrichment analysis of 30 hub genes indicated that inflammation and epithelial-mesenchymal transition (EMT) related genes were mainly concentrated together. Pathway analysis revealed that the PI3K-Akt signaling pathway plays an integral role in CsA-induced AKI. Network analysis identified 3 important miRNAs, mmu-miR-17b-5p, mmu-miR-19b-3p, and mmu-mir-423-5p that may further promote the development of inflammatory responses and EMT by mediating a complex network of factors. Our research provides a clearer understanding the molecular mechanism of this specific drug-induced AKI by CsA use, which is useful for discovering potential targets for gene therapies, and drug development in CsA-induced AKI.

A cell permeable peptide inhibitor of NFAT inhibits macrophage cytokine expression and ameliorates experimental colitis

Nuclear factor of activated T cells (NFAT) plays a critical role in the development and function of immune and non-immune cells. Although NFAT is a central transcriptional regulator of T cell cytokines, its role in macrophage specific gene expression is less defined. Previous work from our group demonstrated that NFAT regulates Il12b gene expression in macrophages. Here, we further investigate NFAT function in murine macrophages and determined the effects of a cell permeable NFAT inhibitor peptide 11R-VIVIT on experimental colitis in mice. Treatment of bone marrow derived macrophages (BMDMs) with tacrolimus or 11R-VIVIT significantly inhibited LPS and LPS plus IFN-γ induced IL-12 p40 mRNA and protein expression. IL-12 p70 and IL-23 secretion were also decreased. NFAT nuclear translocation and binding to the IL-12 p40 promoter was reduced by NFAT inhibition. Experiments in BMDMs from IL-10 deficient (Il10^−/−) mice demonstrate that inhibition of IL-12 expression by 11R-VIVIT was independent of IL-10 expression. To test its therapeutic potential, 11R-VIVIT was administered systemically to Il10^−/− mice with piroxicam-induced colitis. 11R-VIVIT treated mice demonstrated significant improvement in colitis compared to mice treated with an inactive peptide. Moreover, decreased spontaneous secretion of IL-12 p40 and TNF in supernatants from colon explant cultures was demonstrated. In summary, NFAT, widely recognized for its role in T cell biology, also regulates important innate inflammatory pathways in macrophages. Selective blocking of NFAT via a cell permeable inhibitory peptide is a promising therapeutic strategy for the treatment of inflammatory bowel diseases.

Tacrolimus, a calcineurin inhibitor, overcomes treatment unresponsiveness mediated by P-glycoprotein on lymphocytes in refractory rheumatoid arthritis

OBJECTIVE

Tacrolimus, a calcineurin inhibitor, is used for treatment of rheumatoid arthritis (RA). It also inhibits functions of P-glycoprotein, which is involved in drug resistance. We examined the mechanisms of early response to 2-week tacrolimus treatment in patients with RA.

METHODS

One hundred thirteen patients with refractory RA despite at least 3 antirheumatic agents, including methotrexate, were treated with tacrolimus (1.5-3 mg/day) and the response was assessed at 2 weeks. Expression of the multidrug resistance (MDR-1) gene and P-glycoprotein was assessed in peripheral blood mononuclear cells (PBMC) collected from 113 patients and 40 healthy subjects. The drug exclusion function by the P-glycoprotein was measured by the residual amount of intracellular tritium-labeled dexamethasone cell/medium ratio (C/M ratio).

RESULTS

The disease activity of enrolled patients was 5.8 +/- 1.2 (mean +/- SD) by DAS28 erythrocyte sedimentation rate. A good response to tacrolimus was noted at 2 weeks in 22 of 113 patients. At baseline, PBMC of patients with RA showed upregulated expression of MDR-1 gene and P-glycoprotein and low C/M ratio. The response to tacrolimus correlated with P-glycoprotein expression and C/M ratio. A significant improvement in C/M ratio was noted after 2 weeks of treatment. The C/M ratio correlated significantly with P-glycoprotein expression on CD4+ lymphocytes.

CONCLUSION

Early efficacy of tacrolimus treatment depended on its inhibitory effect on the drug exclusion function of P-glycoprotein, leading to restoration of intracellular therapeutic levels of corticosteroids and clinical improvement. Evaluation of P-glycoprotein expression on lymphocytes is potentially useful for predicting the response to RA treatment.

Cyclosporine and tacrolimus for the treatment of rheumatoid arthritis

PURPOSE OF REVIEW

The calcineurin inhibitors cyclosporine and tacrolimus are important treatments for patients with active rheumatoid arthritis, especially in cases of resistance or intolerance to methotrexate or other disease-modifying antirheumatic drugs. Here, we discuss the mechanism, efficacy and safety of cyclosporine and tacrolimus in the treatment of rheumatoid arthritis.

RECENT FINDINGS

Recent clinical trials of cyclosporine have shown the advantages of its combination with methotrexate, glucocorticoids and leflunomide in the treatment of active rheumatoid arthritis. In Japan, tacrolimus monotherapy was found to be quite effective and combination therapy with methotrexate had positive results in an American study. The inhibitory effects of both drugs not only on T lymphocytes, but also on human osteoclast formation, have been demonstrated in basic studies.

SUMMARY

Cyclosporine and tacrolimus are clinically available disease-modifying antirheumatic drugs. Numerous clinical studies have shown the usefulness of these calcineurin inhibitors in monotherapy and also when combined with methotrexate. Although these drugs have similar effects, there are some differences in adverse reactions.

The Impact of Bacterial Genomics on Natural Product Research

"There's life in the old dog yet!" This adage also holds true for natural product research. After the era of natural products was declared to be over, because of the introduction of combinatorial synthesis techniques, natural product research has taken a surprising turn back towards a major field of pharmaceutical research. Current challenges, such as emerging multidrug-resistant bacteria, might be overcome by developments which combine genomic knowledge with applied biology and chemistry to identify, produce, and alter the structure of new lead compounds. Significant biological activity is reported much less frequently for synthetic compounds, a fact reflected in the large proportion of natural products and their derivatives in clinical use. This Review describes the impact of microbial genomics on natural products research, in particularly the search for new lead structures and their optimization. The limitations of this research are also discussed, thus allowing a look into future developments.

The effect of Cyclosporine A on survival time in salicylate-poisoned rats

Salicylate (SAL) produces mitochondrial membrane permeability transition (MPT) with resultant oxidative phosphorylation uncoupling. Cyclosporine A (CSA) inhibits SAL-induced MPT. This study determined if CSA pretreatment prolonged survival time in SAL-poisoned rats. Twenty-nine rats were randomized to receive pre-treatment with either 30 mg/kg CSA or equal volume of control diluent intraperitoneally (i.p.). Four hours later, all rats received 1700 mg/kg sodium salicylate i.p. Survival time, whole blood CSA ([CSA]), and serum sodium ([Na]), glucose and SAL ([SAL]) concentrations were determined. The results showed median survival time for controls was 18 min (95% CI 14-22 min) and for CSA animals was 14 min (95% CI 13-15 min). Univariate and multivariate analyses and Cox proportional hazard regression revealed CSA treatment was associated with higher [SAL], which was associated with shortened survival times. The CSA group also demonstrated shorter survival times for a given [SAL]. In conclusion, CSA pre-treatment shortened survival in SAL-poisoned rats.

Tacrolimus: the good, the bad, and the ugly

The aim of this study was to evaluate the efficacy and side-effects of tacrolimus in pediatric transplant patients previously receiving cyclosporin A (CsA). This study was a retrospective chart review strengthened by a concomitant patient interview. Eleven pediatric cardiac or renal transplant patients, who had been converted from CsA to tacrolimus from October 1995 to January 1999 at The Cleveland Clinic Foundation, were included; there were six renal and five cardiac transplant patients. Each chart was reviewed to assess transplanted organ function pre- and post-conversion. For the six renal transplant patients, creatinine levels and biopsy findings were evaluated. For the five cardiac transplant patients, cardiac catheterization and routine biopsy data were analyzed likewise. Epstein Barr virus (EBV) status was also evaluated in each patient. In addition, each parent or patient was interviewed to ascertain dates of transplant, current medications, and side-effects. The patients' ages ranged from 6 to 20 yr (mean age 14.6 yr). All patients had been converted to tacrolimus. Eight patients were converted for treatment of refractory rejection, two were converted because of CsA-associated side-effects, and one patient was converted empirically for a history of multiple previous transplant rejections. Seven out of eight patients who received tacrolimus for rejection therapy improved. One patient had complete resolution of gingival hyperplasia. Another patient who previously developed hemolytic uremic syndrome on CsA had no further evidence of hemolysis. Four patients were weaned off steroid therapy. Despite conversion, two renal transplant patients progressed to chronic rejection. Five patients exhibited no side-effects. Side-effects experienced included transient hyperglycemia in conjunction with steroid use, headaches, and tremors that subsided rapidly. Four of 11 patients developed post-transplant lymphoproliferative disease (PTLD). Fortunately, reducing the dose of tacrolimus and/or surgical resection of the mass (if present), eradicated the disease. In conclusion, conversion therapy successfully provides an alternate treatment for acute rejection. It also enabled some patients to discontinue steroid therapy, maximizing growth potential. PTLD is a severe, potentially life-threatening complication that needs to be recognized and monitored closely. In conclusion, tacrolimus has been shown to be a very effective agent for the treatment of refractory organ rejection, but must be used cautiously.