The mechanism of action of FK-506 and cyclosporin A

Oceans as a Source of Immunotherapy

Marine flora is taxonomically diverse, biologically active, and chemically unique. It is an excellent resource, which offers great opportunities for the discovery of new biopharmaceuticals such as immunomodulators and drugs targeting cancerous, inflammatory, microbial, and fungal diseases. The ability of some marine molecules to mediate specific inhibitory activities has been demonstrated in a range of cellular processes, including apoptosis, angiogenesis, and cell migration and adhesion. Immunomodulators have been shown to have significant therapeutic effects on immune-mediated diseases, but the search for safe and effective immunotherapies for other diseases such as sinusitis, atopic dermatitis, rheumatoid arthritis, asthma and allergies is ongoing. This review focuses on the marine-originated bioactive molecules with immunomodulatory potential, with a particular focus on the molecular mechanisms of specific agents with respect to their targets. It also addresses the commercial utilization of these compounds for possible drug improvement using metabolic engineering and genomics.

Injury derived autoimmunity: Anti-perlecan/LG3 antibodies in transplantation

Ischemic, immunologic or pharmacological stressors can induce vascular injury and endothelial apoptosis in organ donors, in transplant candidates due to the impact of end stage organ failure on the vasculature, and in association with peri-transplantation events. Vascular injury may shape innate and adaptive immune responses, leading to dysregulation in the balance between tolerance and immunoreactivity to vascular-derived antigens. Mounting evidence shows that the early stages of apoptosis, characterized by the absence of membrane permeabilization, are prone to trigger various modes of intercellular communication allowing neoantigen production, exposure, or both. In this review, we present the evidence for the release of LG3, an immunogenic fragment of perlecan, as a consequence of caspase-3 dependent vascular apoptosis leading to the genesis of anti-LG3 autoantibodies and the consequences of these autoantibodies in native and transplanted kidneys.

Lessons to Learn From Low-Dose Cyclosporin-A: A New Approach for Unexpected Clinical Applications

Cyclosporin-A has been known and used for a long time, since its "fast track" approval in the early 80's. This molecule has rapidly demonstrated unexpected immunosuppressive properties, transforming the history of organ transplantation. Cyclosporin's key effect relies on modulation on T-lymphocyte activity, which explains its role in the prevention of graft rejection. However, whether cyclosporin-A exerts other effects on immune system remains to be determined. Until recently, cyclosporin-A was mainly used at a high-dose, but given the drug toxicity and despite the fear of losing its immunosuppressive effects, there is nowadays a tendency to decrease its dose. The literature has been reporting data revealing a paradoxical effect of low dosage of cyclosporin-A. These low-doses appear to have immunomodulatory properties, with different effects from high-doses on CD8+ T lymphocyte activation, auto-immune diseases, graft-vs.-host disease and cancer. The aim of this review is to discuss the role of cyclosporin-A, not only as a consecrated immunosuppressive agent, but also as an immunomodulatory drug when administrated at low-dose. The use of low-dose cyclosporin-A may become a new therapeutic strategy, particularly to treat cancer.

Efficacy and safety of add-on tacrolimus versus leflunomide in rheumatoid arthritis patients with inadequate response to methotrexate

AIM

To investigate the efficacy and safety of tacrolimus (TAC) versus leflunomide (LEF) when combined with methotrexate (MTX) in rheumatoid arthritis (RA) patients.

METHOD

This was a 24-week multi-center, double-blind, randomized, non-inferiority study targeting RA patients with moderate to severe Disease Activity Score of 28 joints (DAS28 > 3.2) who showed inadequate response to MTX. Patients were randomized into TAC or LEF (add-on to MTX) groups. Initial daily doses of TAC and LEF were 1.5 and 10 mg, respectively, for 4 weeks and then doubled until the end of the study. The primary endpoint was DAS28 comparison at 24 weeks.

RESULTS

Eighty-seven patients were screened in 10 centers and 75 patients were randomized into two groups. Baseline demographics were comparable between TAC + MTX and LEF + MTX groups. The TAC + MTX group was non-inferior to the LEF + MTX group in terms of DAS28 at 24 weeks (mean difference of DAS28: -0.1812, 95% confidence interval: -0.8073, 0.4450). There was a greater number of adverse events in the LEF + MTX group (66 in LEF + MTX and 49 in TAC + MTX). Six patients presented with transaminitis in the LEF + MTX group compared with two patients in the TAC + MTX group.

CONCLUSION

The efficacy of TAC combined with MTX was non-inferior to LEF + MTX. It had a reasonable safety profile in RA patients with moderate to severe disease activity (http://cris.nih.go.kr; KCT0000781).

New insights into immune mechanisms of antiperlecan/LG3 antibody production: Importance of T cells and innate B1 cells

Autoantibodies against perlecan/LG3 (anti-LG3) have been associated with increased risks of delayed graft function, acute rejection, and reduced long-term survival. High titers of anti-LG3 antibodies have been found in de novo renal transplants recipients in the absence of allosensitizing or autoimmune conditions. Here, we seek to understand the pathways controlling anti-LG3 production prior to transplantation. Mice immunized with recombinant LG3 produce concomitantly IgM and IgG anti-LG3 antibodies suggesting a memory response. ELISpot confirmed the presence of LG3-specific memory B cells in nonimmunized mice. Purification of B1 and B2 subtypes identified peritoneal B1 cells as the major source of memory B cells reactive to LG3. Although nonimmunized CD4-deficient mice were found to express LG3-specific memory B cells, depletion of CD4⁺ T cells in wild type mice during immunization significantly decreased anti-LG3 production. These results demonstrate that B cell memory to LG3 is T cell independent but that production of anti-LG3 antibodies requires T cell help. Further supporting an important role for T cells in controlling anti-LG3 levels, we found that human renal transplant recipients show a significant decrease in anti-LG3 titers upon the initiation of CNI-based immunosuppression. Collectively, these results identify T cell targeting interventions as a means of reducing anti-LG3 levels in renal transplant patients.

Brain microglia activation induced by intracranial administration of oligonucleotides and its pharmacological modulation

Oligonucleotide overloading results in type I interferonopathies such as the Aicardi-Goutiéres Syndrome, a progressive encephalopathy determined by an immune response against endogenous DNA/RNA molecules. No therapy targeting pathogenic mechanisms is available for affected patients. Accordingly, we set up an in vitro/in vivo experimental model aimed at reproducing the pathogenic mechanisms of type I interferonopathies, in order to develop an effective pharmacological modulation and toxicological alterations caused by intracranial delivery of encapsulated CpG. The in vitro model used Aicardi-Goutiéres Syndrome immortalized lymphocytes activated by interferon I and co-cultured with human astrocytes; lymphocyte neurotoxicity was attenuated by the calcineurin-inhibitor Tacrolimus and by the anti-interferon monoclonal antibody Sifalimumab. The in vivo model was set up in mice by subcutaneous injection of encapsulated CpG oligonucleotides; the immune-stimulating activity was demonstrated by cytometric analysis in the spleen. To mime pathogenesis of type I interferonopathies in the central nervous system, CpG oligonucleotides were administered intracranially in mice. In the brain, CpG overload induced a rapid activation of macrophage-like microglial cells and focal accumulation mononuclear cells. The subcutaneous administration of Tacrolimus and, more potently, Sifalimumab attenuated CpG-induced brain alterations. These findings shed light on molecular mechanisms triggered by oligonucleotides to induce brain damage. Monoclonal antibodies inhibiting interferon seem a promising therapeutic strategy to protect brain in type I interferonopathies.

Regulatory B cells and advances in transplantation

The effects of B cell subsets with regulatory activity on the immune response to an allograft have evoked increasing interest. Here, we summarize the function and signaling of regulatory B cells (Bregs) and their potential effects on transplantation. These cells are able to suppress the immune system directly via ligand-receptor interactions and indirectly by secretion of immunosuppressive cytokines, particularly IL-10. In experimental animal models, the extensively studied IL-10-producing B cells have shown unique therapeutic advantages in the transplant field. In addition, adoptive transfer of B cell subsets with regulatory activity may reveal a new approach to prolonging allograft survival. Recent clinical observations on currently available therapies targeting B cells have revealed that Bregs play an important role in immune tolerance and that these cells are expected to become a new target of immunotherapy for transplant-related diseases.

Tetramethylpyrazine (TMP) ameliorates corneal neovascularization via regulating cell infiltration into cornea after alkali burn

In the present study, we investigated the underlying mechanism of tetramethylpyrazine (TMP)-medicated inhibition of corneal neovascularization (CNV). Our data showed that TMP could effectively downregulate the expression levels of CXCR4 mRNA and protein, as well as inhibit HUVECs, endothelial cells, tubule formation in vitro. In vivo, alkali burn (1 M NaOH) could remarkably upregulate CXCR4 expression and increase the migration of TNF-α-positive cells to corneal stroma. TMP drops could significantly downregulate CXCR4 expression in cornea, compared to the control. However, there was no difference in the downregulation of CXCR4 between TMP and FK506, an immunosuppressive drug. Moreover, the immunofluorescent staining of CD45 showed TMP and FK506 could significantly restrain the bone marrow (BM)-derived infiltration while the F4/80 staining reflects the suppression of macrophage aggregation. Meanwhile TMP could regulate the Interleukin 10 (IL-10) and FK506 could restrain the Interleukin 2 (IL-2). Furthermore, TMP and FK506 significantly ameliorate corneal opacity and neovascularization. Clinical assessment detected an obvious improvement in TMP and FK506 treatment groups, compared to controls in vivo. Thus, TMP had similar effects in inhibition of immune response and CNV by suppressing BM-infiltrating cells into cornea as FK506. TMP could be a potential agent in eye-drop therapy for cornea damaged by Alkali Burn.

Effect of cyclosporine A on mortality after acute exacerbation of idiopathic pulmonary fibrosis

Background

There is currently no recognized treatment for acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF), and the effect of cyclosporine A in patients with AE-IPF remains unknown.

Methods

We identified patients with AE-IPF who received high-dose methylprednisolone plus cyclosporine A or high-dose methylprednisolone alone from July 1, 2010, to March 31, 2014, using the Diagnosis Procedure Combination database in Japan. We compared in-hospital mortality between patients with and without cyclosporine A by multivariable logistic regression analysis, with adjustment for patient and hospital covariates. Unmeasured confounders were accounted for by instrumental variable analysis based on differential distance.

Results

Eligible patients (n=7,989) were divided into a high-dose methylprednisolone plus cyclosporine A group (n=384) and a high-dose methylprednisolone alone group (n=7,605). There was no significant difference in terms of in-hospital mortality between the groups according to multivariable logistic regression [odds ratio, 1.27; 95% confidence interval (CI), 0.99-1.64; P=0.06] or instrumental variable analysis (odds ratio, 0.94; 95% CI, 0.12-7.67; P=0.96).

Conclusions

Cyclosporine A did not reduce in-hospital mortality in patients with AE-IPF. Randomised controlled studies are required to confirm this apparent lack of effect of cyclosporine A in AE-IPF.

Factors associated with immune hemolytic anemia after pediatric liver transplantation

Immune-mediated hemolytic anemia following SOT is a rare disorder, the risk factors for which are unknown. Our purpose was to analyze a seemingly increased incidence in our center with the aim to identify predisposing factors. This recipients single-center retrospective study reviewed the medical records of 96 pediatric LT between 2000 and 2013. IHA was defined as acute anemia with a positive direct antiglobulin test. Seven cases of immune-mediated hemolytic anemia were identified (incidence 8.5%). Three cases presented during the first 3 months following LT (early IHA), and 4 presented later (late IHA). All patients with late IHA required rituximab. Using univariate analysis, the following factors were associated with IHA onset: BA (P = .04), younger age (P = .04), and the use of IGL-1 preservation solution (P = .05). Late IHA was associated with viral infections occurring beyond 3 months following LT, younger age, and BA (P = .01). Overall, CMV infection was associated with the development of both early and late IHA: CMV-negative recipients who received an organ from a CMV-positive donor were more likely to develop IHA (P = .035), and de novo CMV infection during the first year post-LT was associated with late IHA (P = .03). IHA is a rare complication following pediatric LT, occurring more frequently in younger patients and patients with an initial diagnosis of BA. CMV-negative recipients and patients who experience a de novo CMV infection in the first year following LT seem particularly vulnerable. IGL-1 preservation solution may be associated with an increased likelihood of developing IHA, a novel finding which warrants further investigation.

New frontiers in immunosuppression

Immunosuppressive therapy is arguably the most important component of medical care after lung transplantation. The goal of immunosuppression is to prevent acute and chronic rejection while maximizing patient survival and long-term allograft function. However, the benefits of immunosuppressive therapy must be balanced against the side effects and major toxicities of these medications. Immunosuppressive agents can be classified as induction agents, maintenance therapies, treatments for acute rejection and chronic rejection and antibody directed therapies. Although induction therapy remains an area of controversy in lung transplantation, it is still used in the majority of transplant centers. On the other hand, maintenance immunosuppression is less contentious; but, unfortunately, since the creation of three-drug combination therapy, including a glucocorticoid, calcineurin inhibitor and anti-metabolite, there have been relatively modest improvements in chronic maintenance immunosuppressive regimens. The presence of HLA antibodies in transplant candidates and development of de novo antibodies after transplantation remain a major therapeutic challenge before and after lung transplantation. In this chapter we review the medications used for induction and maintenance immunosuppression along with their efficacy and side effect profiles. We also review strategies and evidence for HLA desensitization prior to lung transplantation and management of de novo antibody formation after transplant. Finally, we review immune tolerance and the future of lung transplantation to limit the toxicities of conventional immunosuppressive therapy.

Review of the biologic and clinical significance of genetic mutations in angioimmunoblastic T-cell lymphoma

Angioimmunoblastic T-cell lymphoma (AITL) is an age-related malignant lymphoma, characterized by immune system-dysregulated symptoms. Recent sequencing studies have clarified the recurrent mutations in ras homology family member A (RHOA) and in genes encoding epigenetic regulators, tet methyl cytosine dioxygenase 2 (TET2), DNA methyl transferase 3 alpha (DNMT3A) and isocitrate dehydrogenase 2, mitochondrial (IDH2), as well as those related to the T-cell receptor signaling pathway in AITL. In this review, we focus on how this genetic information has changed the understanding of the developmental process of AITL and will in future lead to individualized therapies for AITL patients.

In Vitro Phase I Metabolism of CRV431, a Novel Oral Drug Candidate for Chronic Hepatitis B

The cytochrome P450-mediated Phase I in vitro metabolism of CRV431 was studied using selective chemical inhibition and recombinant human enzymes. Additionally, the metabolic profile of CRV431 in human, rat, and monkey liver microsomes was investigated. Liver microsomes were incubated for 0-80 min with CRV431, and the metabolite profile was assessed by electrospray ionization liquid chromatography mass spectrometry (ESI-LCMS). CRV431 was extensively metabolized through oxidation to produce various hydroxylated and demethylated species. Species identified included monohydroxylated CRV431 (two distinct products), dihydroxylated CRV431, demethylated CRV431 (two distinct products), demethylated and hydroxylated CRV431 (two distinct products), didemethylated and hydroxylated CRV431, and didemethylated and dihydroxylated CRV431. The magnitude of metabolism was greatest in monkey, followed by human, followed by rat. Importantly, all of the species identified in human microsomes were correspondingly identified in monkey and/or rat microsomes. Human liver microsome studies using selective chemical inhibition, as well as studies using recombinant human cytochrome P450 enzymes, revealed that the major enzymes involved are cytochromes P450 3A4 and 3A5. Enzymes 1A2, 2B6, 2C8, 2C9, 2C19, and 2D6 are not involved in the in vitro metabolism of CRV431. This information will be useful for the further development of CRV431 both preclinically and clinically.

Calcineurin inhibitors in systemic lupus erythematosus

The calcineurin inhibitors (CNIs) belong to a group of immunosuppressive agents that block T-cell activation through the suppression of the calcium/calcimodulin-dependent phosphatase calcineurin. Agents such as cyclosporine A (CSA) and tacrolimus (TAC) have long been used in patients with systemic lupus erythematosus (SLE). TAC is preferred to CSA in SLE because of the lower frequency of cosmetic, hypertensive and dyslipidemic adverse effects. Recent randomised controlled trials have demonstrated noninferiority of TAC to mycophenolate mofetil (MMF) or cyclophosphamide (CYC) for induction therapy of lupus nephritis. Low-dose combination of TAC and MMF has also been shown to outperform CYC pulses in inducing remission of lupus nephritis in Chinese patients. TAC does not affect fertility and is relatively safe in pregnancy. In SLE patients who are intolerant or refractory to conventional immunosuppressives, or where contraindications to other immunosuppressive agents exist, TAC is an alternative option. However, the therapeutic window of TAC is narrow, and drug level monitoring is required to ensure drug exposure and minimise toxicities. Current evidence of TAC in lupus nephritis is limited to 6 months, and its long-term safety as maintenance therapy of SLE is yet to be determined. Newer chemical analogues of CNIs, such as voclosporin, with less variable plasma concentration are being tested in lupus nephritis.

Autoimmune hemolytic anemia in solid organ transplantation-The role of immunosuppression

Hemolysis after solid organ transplantation can be caused by both immune and non-immune-mediated mechanisms, and the evaluation must take into account issues distinctive to the post-transplant period. Autoimmune hemolytic anemia usually occurs within the first year and has been attributed to immunosuppressive treatment, infections, or underlying post-transplant lymphoproliferative disorder. Review of the literature revealed 59 cases with autoimmune hemolytic anemia mostly in children after liver transplantation. Almost all of the patients at the time of diagnosis received immunosuppression with tacrolimus, and first-line treatment with steroids and/or intravenous immunoglobulin was ineffective for complete remission. Rituximab was used as second-line treatment especially in patients with underlying lymphoproliferative disorders whereas sirolimus showed encouraging results.

HpSlyD inducing CDX2 and VIL1 expression mediated through TCTP protein may contribute to intestinal metaplasia in the stomach

Helicobacter pylori infection is the most important risk factor for gastric intestinal metaplasia (IM). Our previous study demonstrated that infection with H. pylori HpslyD-positive strains associated with IM. To further investigate the signalling pathway involved in HpSlyD-induced IM, CDX2 and VIL1 expressions were determined before and after HpSlyD application. TCTP was knocked down by siRNA or overexpressed by plasmid transfection. An HpSlyD binding protein was used to block HpSlyD's enzymatic activity. The expression of CDX2 and TCTP in gastric diseases was measured by immunohistochemistry. Our results showed HpSlyD induced CDX2 and VIL1 expressions. TCTP protein expression was markedly increased after application of HpSlyD and in an HpSlyD-expressing stable cell line. Downregulation of TCTP protein led to decreased HpSlyD-induced CDX2 and VIL1. Overexpression of TCTP protein improved the expression of CDX2 and VIL1. Co-application of HpSlyD and FK506 led to significant reductions in CDX2, VIL1, and TCTP expression. Immunohistochemistry demonstrated that CDX2 and TCTP expression was higher in HpslyD-positive specimens compared with HpslyD-negative ones. Expression of CDX2 was positively correlated with TCTP in HpslyD-positive cells. Our study is the first to show that HpSlyD induction of CDX2 and VIL1 expression mediated through TCTP may contribute to IM in the stomach.

Cycloheximide promotes paraptosis induced by inhibition of cyclophilins in glioblastoma multiforme

Cancer is the second leading cause of death worldwide. Current treatment strategies based on multi-agent chemotherapy and/or radiation regimens have improved overall survival in some cases. However, resistance to apoptosis often develops in cancer cells, and its occurrence is thought to contribute to treatment failure. Non-apoptotic cell death mechanisms have become of great interest, therefore, in hopes that they would bypass tumor cell resistance. Glioblastoma multiforme (GBM), a grade IV astrocytic tumor is the most frequent brain tumor in adults, and has a high rate of mortality. We report that NIM811, a small molecule cyclophilin-binding inhibitor, induces catastrophic vacuolization and cell death in GBM cells. These unique features are distinct from many known cell death pathways, and are associated with an incompletely defined cell death mechanism known as paraptosis. We found that NIM811-induced paraptosis is due to unresolved ER stress. The abnormal upregulation of protein translation was responsible for the build-up of misfolded or unfolded proteins in ER, whereas pro-survival autophagy and UPR signals were shutdown during prolonged treatment with NIM811. Although cycloheximide has been claimed to suppress paraptosis, instead we find that it only temporarily delayed vacuole formation, but actually enhanced paraptotic cell death in the long term. On the other hand, mTOR inhibitors rescued cells from NIM811-induced paraptosis by sustaining autophagy and the UPR, while specifically restraining cap-dependent translation. These findings not only provide new insights into the mechanisms underlying paraptosis, but also shed light on a potential approach to enhance GBM treatment.

Cyclosporine: A Historical Perspective on Its Role in the Treatment of Noninfectious Uveitis

The history of cyclosporine and uveitis is intertwined with the development of experimental autoimmune uveitis (EAU) animal models and the understanding that T lymphocytes play a major role in the pathogenesis of uveitis. The early studies of CsA in uveitis also demonstrated the power of collaborative efforts in translational research. Dr. Robert Nussenblatt and his colleagues were the first to show that CsA can inhibit EAU. Over many years after the initial CsA experiments, Dr. Nussenblatt's group as well as others continued to study CsA under experimental conditions as well as in clinical trials with human patients. The data and observations from these studies significantly advanced our knowledge of uveitis pathophysiology and demonstrated the value of well-designed masked, controlled treatment trials in uveitis. Dr. Nussenblatt and his collaborators delved into the most significant adverse effect of CsA, renal toxicity, and helped elucidate the pathophysiology of renal injury. They explored adjunctive treatments to improve the efficacy and decrease the toxicity of CsA and also studied other members of the cyclosporine family. Among the immunosuppressives used to treat ocular inflammation, CsA was the first, and remains the only medication comprehensively studied under both experimental and clinical conditions.

FK506, an Immunosuppressive Drug, Induces Autophagy by Binding to the V-ATPase Catalytic Subunit A in Neuronal Cells

The drug FK506 (tacrolimus, fujimycin) exerts its immunosuppressive effects by regulating the nuclear factor of the activated T-cell (NFAT) family of transcription factors. However, FK506 also exhibits neuroprotective effects, but its direct target proteins that mediate these effects have not been determined. To identify the target proteins responsible for FK506's neuroprotective effects, the drug affinity responsive target stability (DARTS) method was performed using label-free FK506, and LC-MS/MS analysis of the FK506-treated proteome was also performed. Using DARTS and LC-MS/MS analyses in combination with reference studies, V-ATPase catalytic subunit A (ATP6V1A) was identified as a new target protein of FK506. The biological relevance of ATP6V1A in mediating the neuroprotective effects of FK506 was validated by analyzing FK506 activity with respect to autophagy via acridine orange staining and transcription factor EB (TFEB) translocation assay. These analyses demonstrated that the binding of FK506 with ATP6V1A induces autophagy by activating the translocation of TFEB from the cytosol into the nucleus. Because autophagy has been identified as a mechanism for treating neurodegenerative diseases and because we have demonstrated that FK506 induces autophagy, this study demonstrates that FK506 is a possible new therapy for treating neurodegenerative diseases.

Moderator's view: The use of calcineurin inhibitors in the treatment of lupus nephritis

Lupus nephritis (LN) is one of the most severe manifestations of systemic lupus erythematosus (SLE), affecting ∼50% of patients, and both renal disease and treatment-related toxicity contribute to significant morbidity and mortality. Although our understanding of the aetiopathogenesis of LN is improving, treatment still remains a challenge, with the achievement of complete remission at 1 year in <50% of patients treated with current standard of care immunosuppressive therapy; this is associated with considerable short- and long-term side effects, some of which further contribute to non-adherence. Calcineurin inhibitors (CNIs) have been successfully used in organ transplantation and there is increasing evidence that cyclosporin A (CSA), and especially tacrolimus (TAC), are also effective in the treatment of LN. Randomised controlled trials showed similar efficacy for TAC when compared with mycophenolate mofetil (MMF) and multitarget therapy, including TAC and low-dose MMF, and resulted in significantly more complete remissions and overall responses compared with intravenous cyclophosphamide (CYC). Flares are observed in up to 45% of patients with LN, and an increase in relapse rate following induction with CNIs may be an issue. Most studies on this matter have been restricted to patients from Asia, and studies in more balanced cohorts are desirable. Moreover, there is a need to understand and determine the long-term effects of CNIs on renal function, proteinuria and comorbidities, with a special focus on cardiovascular risk. In this 'Pros and Cons' debate, the potential benefits and disadvantages of CNIs in the treatment of LN will be critically highlighted.

Pro: The use of calcineurin inhibitors in the treatment of lupus nephritis

Renal disease in systemic lupus erythematosus (SLE) carries significant morbidity and mortality. Cyclophosphamide (CYC)- and mycophenolate mofetil (MMF)-based induction regimens are not ideal in terms of efficacy and toxicity. The adverse effects of CYC, such as infection risk, infertility, urotoxicity and oncogenicity, limit its use in lupus nephritis. Although MMF is non-inferior to CYC as induction therapy and has reduced gonadal toxicity and oncogenic potential, meta-analyses of clinical trials do not show a lower rate of infective and gastrointestinal complications. Tacrolimus (TAC) has recently been shown to have equal efficacy to either MMF or CYC for inducing remission of lupus nephritis. A low-dose combination of MMF and TAC appears to be more effective than intravenous CYC pulses in Chinese patients, and has potential to replace the more toxic CYC regimens in high-risk subgroups. TAC may be considered as another non-CYC alternative for induction therapy of lupus nephritis and in those with refractory disease or intolerance to CYC or MMF. TAC has no negative effect on fertility in younger women, and unlike MMF and CYC, it is safe in pregnancy. However, TAC has a narrow therapeutic window and drug level monitoring is required to ensure drug exposure and minimize acute toxicities. Current evidence for the efficacy of TAC in lupus nephritis is limited to 6 months and the incidence of renal flare after discontinuation of therapy or switching to azathioprine appears to be higher than other induction agents. Long-term data and the incidence of chronic nephrotoxicity of TAC as maintenance therapy in lupus nephritis are currently lacking and further prospective trials are needed to address these issues.

Variation in PPP3CC Genotype Is Associated with Long-Term Recovery after Severe Brain Injury

After experimental traumatic brain injury (TBI), calcineurin is upregulated; blocking calcineurin is associated with improved outcomes. In humans, variation in the calcineurin A-gamma gene (PPP3CC) has been associated with neuropsychiatric disorders, though any role in TBI recovery remains unknown. This study examines associations between PPP3CC genotype and mortality, as well as gross functional status assessed at admission using the Glasgow Coma Scale (GCS) and at 3, 6, and 12 months after severe TBI using the Glasgow Outcome Score (GOS). The following tagging single nucleotide polymorphisms (tSNPs) in PPP3CC were genotyped: rs2443504, rs2461491, rs2469749, and rs10108011. The rs2443504 AA genotype was univariately associated with GCS (p = 0.022), GOS at 3, 6, and 12 months (p = 0.002, p = 0.034, and p = 0.004, respectively), and mortality (p = 0.007). In multivariate analysis controlling for age, sex, and GCS, the AA genotype of rs2443504 was associated with GOS at 3 (p = 0.02), and 12 months (p = 0.01), with a trend toward significance at 6 months (p = 0.05); the AA genotype also was associated with mortality in the multivariate model (p = 0.04). Further work is warranted to better understand the role of calcineurin, as well as the genes encoding it and their relevance to outcomes after brain injury.

IgE responses to exogenous and endogenous allergens in atopic dermatitis patients under long-term systemic cyclosporine A treatment

Atopic dermatitis (AD) patients mount IgE antibody responses to a variety of environmental allergens and also to autoantigens. We analyzed serum samples from four AD patients who had received oral cyclosporine A (CyA) treatment for up to 17 months regarding IgE autoreactivity to nitrocellulose-blotted human epithelial cell extracts and IgE levels to environmental allergens by quantitative ImmunoCap measurements. Skin inflammation was assessed by SCORAD. During full-dose treatment, a strong reduction in T-cell-mediated skin symptoms was observed which reappeared when CyA treatment was reduced or stopped. The intensity of IgE autoreactivity seemed to follow skin inflammation as it was reduced during full-dose treatment and increased upon inflammation. Interestingly, IgE levels to exogenous allergens were boosted by allergen exposure, declined thereafter, and seemed to be unaffected by CyA. Our data thus indicate that allergen-specific IgE production is boosted by allergen contact and cannot be reduced by CyA-mediated T-cell suppression.

Posterior Reversible Encephalopathy Syndrome in a Bone Marrow Transplant Patient: A Complication of Immunosuppressive Drugs?

Posterior reversible encephalopathy is a complex but well-recognized clinical and radiological entity associated with a variety of benign and malignant conditions including hypertensive encephalopathy, eclampsia, renal failure and immunosuppressive drugs. The pathogenesis is incompletely understood, although it seems to be related to the breakthrough of auto-regulation and endothelial dysfunction. The clinical syndromes typically involve headache, altered mental status, seizures, visual disturbance and other focal neurological signs and radiographically reversible vasogenic subcortical edema without infarction. Here, we report a case of posterior reversible encephalopathy syndrome in a patient with chronic myeloid leukemia who received allogenic bone marrow transplantation (allo-BMT) and immunosuppressive drugs.

Calcineurin inhibitors dampen humoral immunity by acting directly on naive B cells

Calcineurin inhibitors (CNI), used frequently in solid organ transplant patients, are known to inhibit T cell proliferation, but their effect on humoral immunity is far less studied. Total and naive B cells from healthy adult donors were cultured in immunoglobulin (Ig)A- or IgG/IgE-promoting conditions with increasing doses of cyclosporin, tacrolimus, rapamycin or methylprednisolone. The effect on cell number, cell division, plasmablast differentiation and class-switching was tested. To examine the effect on T follicular helper (Tfh) cell differentiation, naive CD4(+) T cells were cultured with interleukin (IL)-12 and titrated immunosuppressive drug (IS) concentrations. Total B cell function was not affected by CNI. However, naive B cell proliferation was inhibited by cyclosporin and both CNI decreased plasmablast differentiation. Both CNI suppressed IgA, whereas only cyclosporin inhibited IgE class-switching. Rapamycin had a strong inhibitory effect on B cell function. Strikingly, methylprednisolone, increased plasmablast differentiation and IgE class-switching from naive B cells. Differentiation of Tfh cells decreased with increasing IS doses. CNI affected humoral immunity directly by suppressing naive B cells. CNI, as well as rapamycin and methylprednisolone, inhibited the in-vitro differentiation of Tfh from naive CD4(+) T cells. In view of its potent suppressive effect on B cell function and Tfh cell differentiation, rapamycin might be an interesting candidate in the management of B cell mediated complications post solid organ transplantation.

Amoebae-Based Screening Reveals a Novel Family of Compounds Restricting Intracellular Legionella pneumophila

The causative agent of Legionnaires' disease, Legionella pneumophila, grows in environmental amoebae and mammalian macrophages within a distinct compartment, the 'Legionella-containing vacuole' (LCV). Intracellular bacteria are protected from many antibiotics, and thus are notoriously difficult to eradicate. To identify novel compounds that restrict intracellular bacterial replication, we previously developed an assay based on a coculture of amoebae and GFP-producing L. pneumophila. This assay was used to screen a pathway-based, highly diverse chemical library, referred to as the Sinergia library. In this work, we chose to focus on a group of 11 hit compounds, the majority of which originated from the query molecule CN585, a compound that targets the protein phosphatase calcineurin. Further studies on 78 related compound variants revealed crucial structural attributes, namely a triple-ring scaffold with a central triazine moiety, substituted in positions 3 and 5 by two piperidine or pyrrolidine rings, and in position 1 by an amine group bearing a single aliphatic chain moiety. The most effective compound, ZINC00615682, inhibited intracellular replication of L. pneumophila with an IC50 of approximately 20 nM in Acanthamoeba castellanii and slightly less efficiently in Dictyostelium discoideum or macrophages. Pharmacological and genetic attempts to implicate calcineurin in the intracellular replication of L. pneumophila failed. Taken together, these results show that the amoebae-based screen and structure-activity relationship analysis is suitable for the identification of novel inhibitors of the intracellular replication of L. pneumophila. The most potent compound identified in this study targets (an) as yet unidentified host factor(s).

Acute exacerbation of idiopathic pulmonary fibrosis-a review of current and novel pharmacotherapies

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive form of lung disease of unknown etiology for which a paucity of therapies suggest benefit, and for which none have demonstrated improved survival. Acute exacerbation of IPF (AE-IPF) is defined as a sudden acceleration of the disease or an idiopathic acute injury superimposed on diseased lung that leads to a significant decline in lung function. An AE-IPF is associated with a mortality rate as high as 85% with mean survival periods of between 3 to 13 days. Under these circumstances, mechanical ventilation (MV) is controversial, unless used a as a bridge to lung transplantation. Judicious fluid management may be helpful. Pharmaceutical treatment regimens for AE-IPF include the use of high dose corticosteroids with or without immunosuppressive agents such as cyclosporine A (CsA), and broad spectrum antibiotics, despite the lack of convincing evidence demonstrating benefit. Newer research focuses on abnormal wound healing as a cause of fibrosis and preventing fibrosis itself through blocking growth factors and their downstream intra-cellular signaling pathways. Several novel pharmaceutical approaches are discussed.

Facile supermolecular aptamer inhibitors of L-selectin

Multivalent interactions occur frequently in nature, where they mediate high-affinity interactions between cells, proteins, or molecules. Here, we report on a method to generate multivalent aptamers (Multi-Aptamers) that target L-selectin function using rolling circle amplification (RCA). We find that the L-selectin Multi-Aptamers have increased affinity compared to the monovalent aptamer, are specific to L-selectin, and are capable of inhibiting interactions with endogenous ligands. In addition, the Multi-Aptamers efficiently inhibit L-selectin mediated dynamic adhesion in vitro and homing to secondary lymphoid tissues in vivo. Importantly, our method of generating multivalent materials using RCA avoids many of the challenges associated with current multivalent materials in that the Multi-Aptamers are high affinity, easily produced and modified, and biocompatible. We anticipate that the Multi-Aptamers can serve as a platform technology to modulate diverse cellular processes.

Characteristic features of tacrolimus-induced lung disease in rheumatoid arthritis patients

This paper aims to study the background and clinical characteristics of tacrolimus (TAC)-induced lung disease. A case of a rheumatoid arthritis (RA) patient who developed TAC-induced interstitial lung disease (TAC-ILD) is reported. The Japanese Pharmaceuticals and Medical Devices Agency (PMDA) website was searched for cases of TAC-ILD and its prevalence among all cases of TAC-related adverse events. As for cases of TAC-ILD, its underlying disease, preexisting lung diseases, and fatal outcome were also searched. Literature review of TAC-ILD cases was added. A 65-year-old female RA patient with preexisting bronchiectasis developed near-fatal TAC-ILD. Amelioration of RA, ground-glass opacities in the upper, anterior, and central lung fields, and decrease in peripheral blood lymphocyte count were the major findings in this patient. A search of the PMDA website revealed the following: the prevalence of TAC-ILD was 3 % of all cases of TAC-related adverse events, 56 out of 85 RA cases (66 %), and one out of 15 other cases had a preexisting lung disease; the prevalences of fatal outcome in RA and other cases were 24 and 38 %, respectively. A few cases in the literature had preexisting ILD and developed diffuse alveolar damage. In our case, preexisting bronchiectasis, arthritis remission, newly developed ground-glass opacities (GGOs) in the upper, anterior, and central lung fields, and decrease in peripheral blood lymphocyte count were the major findings. From the search of the PMDA website, about one fourth of the cases with TAC-related lung injury had a fatal outcome, and among RA patients, two thirds had preexisting lung diseases.

Conversion to a sirolimus-based regimen is associated with lower incidence of BK viremia in low-risk kidney transplant recipients

BACKGROUND

BK viral nephropathy is an increasingly recognized cause of early allograft loss in kidney transplantation. This study aimed to determine whether a sirolimus (Sir)-based calcineurin inhibitor-sparing regimen is associated with a lower incidence of BK viremia.

METHODS

This was a single-center retrospective study. Patients were either on tacrolimus (Tac)-based or on Sir-based immunosuppression. Conversion from Tac to Sir occurred at or after 3 months if patients were <62 years of age, had calculated panel reactive antibodies of <20%, and did not have acute early rejection.

RESULTS

Incidence of clinically significant BK viremia was 17.9% in the Tac group and 4.3% in the Sir group. Cox regression multivariate analysis showed that male gender (hazard ratio [HR] = 2.87) and switch to Sir (HR = 0.333) impacted the incidence of BK viremia. Kaplan-Meier analysis showed a higher BK-free survival in the Sir group. A trend was seen toward shorter time to resolution of BK viremia and lower peak viremia in the Sir group. Patients on Sir had a higher estimated glomerular filtration rate at each time point; 34% of patients discontinued Sir because of side effects.

CONCLUSION

Conversion to Sir-based maintenance immunosuppression at or about 3 months after kidney transplantation correlates with a lower incidence of BK viremia.

Estradiol rapidly modulates synaptic plasticity of hippocampal neurons: Involvement of kinase networks

Estradiol (E2) is locally synthesized within the hippocampus in addition to the gonads. Rapid modulation of hippocampal synaptic plasticity by E2 is essential for synaptic regulation. Molecular mechanisms of modulation through synaptic estrogen receptor (ER) and its downstream signaling, however, have been still unknown. We investigated induction of LTP by the presence of E2 upon weak theta burst stimulation (weak-TBS) in CA1 region of adult male hippocampus. Since only weak-TBS did not induce full-LTP, weak-TBS was sub-threshold stimulation. We observed LTP induction by the presence of E2, after incubation of hippocampal slices with 10nM E2 for 30 min, upon weak-TBS. This E2-induced LTP was blocked by ICI, an ER antagonist. This E2-LTP induction was inhibited by blocking Erk MAPK, PKA, PKC, PI3K, NR2B and CaMKII, individually, suggesting that Erk MAPK, PKA, PKC, PI3K and CaMKII may be involved in downstream signaling for activation of NMDA receptors. Interestingly, dihydrotestosterone suppressed the E2-LTP. We also investigated rapid changes of dendritic spines (=postsynapses) in response to E2, using hippocampal slices from adult male rats. We found 1nM E2 increased the density of spines by approximately 1.3-fold within 2h by imaging Lucifer Yellow-injected CA1 pyramidal neurons. The E2-induced spine increase was blocked by ICI. The increase in spines was suppressed by blocking PI3K, Erk MAPK, p38 MAPK, PKA, PKC, LIMK, CaMKII or calcineurin, individually. On the other hand, blocking JNK did not inhibit the E2-induced spine increase. Taken together, these results suggest that E2 rapidly induced LTP and also increased the spine density through kinase networks that are driven by synaptic ER. This article is part of a Special Issue entitled SI: Brain and Memory.

Rapid increase of spines by dihydrotestosterone and testosterone in hippocampal neurons: Dependence on synaptic androgen receptor and kinase networks

Rapid modulation of hippocampal synaptic plasticity by locally synthesized androgen is important in addition to circulating androgen. Here, we investigated the rapid changes of dendritic spines in response to the elevation of dihydrotestosterone (DHT) and testosterone (T), by using hippocampal slices from adult male rats, in order to clarify whether these signaling processes include synaptic/extranuclear androgen receptor (AR) and activation of kinases. We found that the application of 10nM DHT and 10nM T increased the total density of spines by approximately 1.3-fold within 2h, by imaging Lucifer Yellow-injected CA1 pyramidal neurons. Interestingly, DHT and T increased different head-sized spines. While DHT increased middle- and large-head spines, T increased small-head spines. Androgen-induced spinogenesis was suppressed by individually blocking Erk MAPK, PKA, PKC, p38 MAPK, LIMK or calcineurin. On the other hand, blocking CaMKII did not inhibit spinogenesis. Blocking PI3K altered the spine head diameter distribution, but did not change the total spine density. Blocking mRNA and protein synthesis did not suppress the enhancing effects induced by DHT or T. The enhanced spinogenesis by androgens was blocked by AR antagonist, which AR was localized postsynaptically. Taken together, these results imply that enhanced spinogenesis by DHT and T is mediated by synaptic/extranuclear AR which rapidly drives the kinase networks. This article is part of a Special Issue entitled SI: Brain and Memory.

IL-15 is decreased upon CsA and FK506 treatment of acute rejection following heart transplantation in mice

The aim of this study was to investigate the effect of cyclosporine A (CsA) and tacrolimus (FK506) on interleukin-15 (IL-15) production during acute rejection following heart transplantation in mice. Inbred male Balb/c (H‑2d) and C57BL/6 (H-2b) mice were used to establish a heterotopic intra-abdominal cardiac transplantation model. The mice were divided in four groups: syngeneic control, allogeneic acute rejection, allogeneic rejection treated with CsA, and allogeneic rejection treated with FK506. The expression of IL-15, IL-2, and tumor necrosis factor-α (TNF-α) was measured using reverse transcription-polymerase chain reaction (RT-PCR) and western blotting. A low level of IL-15 was detected in transplanted hearts of the control group, with a significant increase observed in the allogeneic acute rejection group. Compared to the allogeneic acute rejection group, IL-15 expression was significantly decreased in the CsA- and FK506-treated allogeneic rejection groups. The TNF-α expression pattern was similar to that of IL-15 in all groups. IL-2 expression was increased in the allogeneic acute rejection group and was inhibited in mice treated with CsA and FK506. In conclusion, increased IL-15 expression in rejected murine heart grafts may be reduced by CsA and FK506 in vivo.

Acute modulation of synaptic plasticity of pyramidal neurons by activin in adult hippocampus

Activin A is known as a neuroprotective factor produced upon acute excitotoxic injury of the hippocampus (in pathological states). We attempt to reveal the role of activin as a neuromodulator in the adult male hippocampus under physiological conditions (in healthy states), which remains largely unknown. We showed endogenous/basal expression of activin in the hippocampal neurons. Localization of activin receptors in dendritic spines (=postsynapses) was demonstrated by immunoelectron microscopy. The incubation of hippocampal acute slices with activin A (10 ng/mL, 0.4 nM) for 2 h altered the density and morphology of spines in CA1 pyramidal neurons. The total spine density increased by 1.2-fold upon activin treatments. Activin selectively increased the density of large-head spines, without affecting middle-head and small-head spines. Blocking Erk/MAPK, PKA, or PKC prevented the activin-induced spinogenesis by reducing the density of large-head spines, independent of Smad-induced gene transcription which usually takes more than several hours. Incubation of acute slices with activin for 2 h induced the moderate early long-term potentiation (moderate LTP) upon weak theta burst stimuli. This moderate LTP induction was blocked by follistatin, MAPK inhibitor (PD98059) and inhibitor of NR2B subunit of NMDA receptors (Ro25-6981). It should be noted that the weak theta burst stimuli alone cannot induce moderate LTP. These results suggest that MAPK-induced phosphorylation of NMDA receptors (including NR2B) may play an important role for activin-induced moderate LTP. Taken together, the current results reveal interesting physiological roles of endogenous activin as a rapid synaptic modulator in the adult hippocampus.

Tacrolimus associated posterior reversible encephalopathy syndrome - a case series and review

Tacrolimus is an immunosuppressive drug mainly used to lower the risk of transplant rejection in individuals who are post solid organ or hematopoietic transplantation. It is a macrolide which reduces peptidyl-propyl isomerase activity and inhibits calcineurin, thus inhibiting T-lymphocyte signal transduction and interleukin-2 (IL-2) transcription. It has been associated with Posterior Reversible Encephalopathy Syndrome (PRES), a disease of sudden onset that can present as a host of different symptoms, depending on the affected area of the brain. While infectious causes of encephalopathy must always be entertained, the differential diagnosis should also include PRES in the appropriate context. We report three cases of PRES in patients with acute myeloid leukemia (AML) placed on tacrolimus after receiving a bone marrow transplant (BMT). The focus of this review is to enhance clinical recognition of PRES as it is related to an adverse effect of Tacrolimus in the setting of hematopoietic transplantation.

Ciclosporin use during pregnancy

Ciclosporin (cyclosporine) is an immunosuppressive drug first approved for use in organ transplantation to prevent rejection. Ciclosporin is also known to be used for the treatment of psoriasis, rheumatoid arthritis, systemic lupus erythematosus and inflammatory bowel disease, among other indications. While it is recommended that all medications that are not absolutely necessary should be avoided during pregnancy, this may not be an option for many women whose quality of life is significantly impacted without treatment, or for those who must continue immunosuppressive therapy to avoid organ rejection. The purpose of this review is to provide a comprehensive report from the literature of ciclosporin exposure during pregnancy. PubMed, MEDLINE and the Cochrane Database of Systematic Reviews were searched for English-language articles published from 1970 to 2012 that included reports of pregnant women treated at any time during pregnancy with ciclosporin. On an initial search, it was evident that much of the available information is limited to pregnancy after transplant, which suggests that ciclosporin use during pregnancy appears to be associated with premature delivery and low birthweight infants. Comorbidities such as hypertension, pre-eclampsia and gestational diabetes mellitus are also reported at higher incidences than the general population. Medical literature concerning women with autoimmune disorders exposed to ciclosporin during pregnancy are currently limited to case reports and registry data, and, as such, it is difficult to determine if any risks associated with ciclosporin therapy during pregnancy are due to exposure to the drug alone or to pre-existing maternal comorbidities. The literature suggests that ciclosporin therapy during pregnancy should be carefully considered by the treating physician, but may be a safe alternative for patients with autoimmune disease refractory to conventional treatment. Continued monitoring of this patient population remains a key component to understanding the risk factors associated with ciclosporin exposure during pregnancy.

Practical guidelines for the use of steroid-sparing agents in the treatment of chronic pruritus

Chronic pruritus in the adult patient is both an underappreciated and a difficult to treat condition. In the vast majority of cases, itch is the result of inflammatory skin disease and therefore may be responsive to systemic anti-inflammatory therapies. Urticarial dermatitis is an under-recognized cause of chronic itch in the adult population. Patients with this disorder are characterized by prolonged, prednisone-responsive pruritus, often in the absence of substantial cutaneous findings. Skin findings, when present, can range from subtle, persistent urticarial lesions to excoriated papules, often intermixed with urticaria, eczematous change, and lichenification secondary to chronic scratching. Hereby, we describe our algorithm for evaluation and management of adult patients with refractory pruritus (urticarial dermatitis in particular), including evaluation for other etiologies of pruritus, pre-immunosuppression workup, and the use of azathioprine and other steroid-sparing agents for treatment of recalcitrant itch.

Cyclophilin A as a New Therapeutic Target for Hepatitis C Virus-induced Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) related to hepatitis B virus (HBV) and hepatitis C virus (HCV) infections is thought to account for more than 80% of primary liver cancers. Both HBV and HCV can establish chronic liver inflammatory infections, altering hepatocyte and liver physiology with potential liver disease progression and HCC development. Cyclophilin A (CypA) has been identified as an essential host factor for the HCV replication by physically interacting with the HCV non structural protein NS5A that in turn interacts with RNA-dependent RNA polymerase NS5B. CypA, a cytosolic binding protein of the immunosuppressive drug cyclosporine A, is overexpressed in many cancer types and often associated with malignant transformation. Therefore, CypA can be a good target for molecular cancer therapy. Because of antiviral activity, the CypA inhibitors have been tested for the treatment of chronic hepatitis C. Nonimmunosuppressive Cyp inhibitors such as NIM811, SCY-635, and Alisporivir have attracted more interests for appropriating CypA for antiviral chemotherapeutic target on HCV infection. This review describes CypA inhibitors as a potential HCC treatment tool that is contrived by their obstructing chronic HCV infection and summarizes roles of CypA in cancer development.

Role of calcineurin and actin dynamics in regulated secretion of microneme proteins in Plasmodium falciparum merozoites during erythrocyte invasion

Plasmodium falciparum invades host erythrocytes by multiple invasion pathways. The invasion of erythrocytes by P. falciparum merozoites is a complex process that requires multiple interactions between host receptors and parasite ligands. A number of parasite proteins that mediate interaction with host receptors during invasion are localized to membrane-bound apical organelles referred to as micronemes and rhoptries. The timely release of these proteins to the merozoite surface is crucial for receptor engagement and invasion. It has been demonstrated previously that exposure of merozoites to a low potassium (K(+)) ionic environment as found in blood plasma leads to a rise in cytosolic calcium (Ca(2+)), which triggers microneme secretion. The signalling pathways that regulate microneme discharge in response to rise in cytosolic Ca(2+) are not completely understood. Here, we show that a P. falciparum Ca(2+)-dependent protein phosphatase, calcineurin (PfCN), is an essential regulator of Ca(2+)-dependent microneme exocytosis. An increase in PfCN activity was observed in merozoites following exposure to a low K(+) environment. Treatment of merozoites with calcineurin inhibitors such as FK506 and cyclosporin A prior to transfer to a low K(+) environment resulted in inhibition of secretion of microneme protein apical merozoite antigen-1 (PfAMA-1). Inhibition of PfCN was shown to result in reduced dephosphorylation and depolymerization of apical actin, which appears to be criticalfor microneme secretion. PfCN thus serves as an effector of Ca(2+)-dependent microneme exocytosis by regulating depolymerization of apical actin. Inhibitors that target PfCN block microneme exocytosis and limit growth of P. falciparum blood-stage parasites providing a novel approach towards development of new therapeutic strategies against malaria.

Tacrolimus (FK506) prevents early stages of ethanol induced hepatic fibrosis by targeting LARP6 dependent mechanism of collagen synthesis

Tacrolimus (FK506) is a widely used immunosuppressive drug. Its effects on hepatic fibrosis have been controversial and attributed to immunosuppression. We show that in vitro FK506, inhibited synthesis of type I collagen polypeptides, without affecting expression of collagen mRNAs. In vivo, administration of FK506 at a dose of 4 mg/kg completely prevented development of alcohol/carbon tetrachloride induced liver fibrosis in rats. Activation of hepatic stellate cells (HSCs) was absent in the FK506 treated livers and expression of collagen α2(I) mRNA was at normal levels. Collagen α1(I) mRNA was increased in the FK506 treated livers, but this mRNA was not translated into α1(I) polypeptide. No significant inflammation was associated with the fibrosis model used. FK506 binding protein 3 (FKBP3) is one of cellular proteins which binds FK506 with high affinity. We discovered that FKBP3 interacts with LARP6 and LARP6 is the major regulator of translation and stability of collagen mRNAs. In the presence of FK506 the interaction between FKBP3 and LARP6 is weakened and so is the pull down of collagen mRNAs with FKBP3. We postulate that FK506 inactivates FKBP3 and that lack of interaction of LARP6 and FKBP3 results in aberrant translation of collagen mRNAs and prevention of fibrosis. This is the first report of such activity of FK506 and may renew the interest in using this drug to alleviate hepatic fibrosis.

The optimal immunosuppressive therapy for aplastic anemia

Immunosuppressive treatment (IST) has been the most effective therapeutic modality for patients with aplastic anemia (AA) who are not eligible for allogeneic stem cell transplantation from HLA-matched siblings because of donor unavailability, old age, or comorbidities. The combination of horse anti-thymocyte globulin (ATG) with cyclosporine A (CsA) has shown satisfactory results for these patients, and so it has been regarded as the standard IST regimen. However, treatment failure including unresponsiveness, relapse, and occurrence of clonal evolution remains a major problem, although the results of IST have been improved in the past two decades. Many studies have been conducted to overcome these problems; however, they have yet to show any satisfactory results. This review will discuss immune-mediated pathophysiology of AA, which is associated with therapeutic targets of immunosuppressive agents and clinical outcomes of most commonly used IST regimens. Several trials to improve IST including the addition of other immunosuppressive agents or growth factors to standard IST regimen, comparison between horse ATG/CsA and rabbit ATG/CsA as first-line treatment, and promising alternative agents including alemtuzumab and eltrombopag will also be discussed, focusing on recently published literatures.

Design and physicochemical characterization of advanced spray-dried tacrolimus multifunctional particles for inhalation

The aim of this study was to design, develop, and optimize respirable tacrolimus microparticles and nanoparticles and multifunctional tacrolimus lung surfactant mimic particles for targeted dry powder inhalation delivery as a pulmonary nanomedicine. Particles were rationally designed and produced at different pump rates by advanced spray-drying particle engineering design from organic solution in closed mode. In addition, multifunctional tacrolimus lung surfactant mimic dry powder particles were prepared by co-dissolving tacrolimus and lung surfactant mimic phospholipids in methanol, followed by advanced co-spray-drying particle engineering design technology in closed mode. The lung surfactant mimic phospholipids were 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-[phosphor-rac-1-glycerol]. Laser diffraction particle sizing indicated that the particle size distributions were suitable for pulmonary delivery, whereas scanning electron microscopy imaging indicated that these particles had both optimal particle morphology and surface morphology. Increasing the pump rate percent of tacrolimus solution resulted in a larger particle size. X-ray powder diffraction patterns and differential scanning calorimetry thermograms indicated that spray drying produced particles with higher amounts of amorphous phase. X-ray powder diffraction and differential scanning calorimetry also confirmed the preservation of the phospholipid bilayer structure in the solid state for all engineered respirable particles. Furthermore, it was observed in hot-stage micrographs that raw tacrolimus displayed a liquid crystal transition following the main phase transition, which is consistent with its interfacial properties. Water vapor uptake and lyotropic phase transitions in the solid state at varying levels of relative humidity were determined by gravimetric vapor sorption technique. Water content in the various powders was very low and well within the levels necessary for dry powder inhalation, as quantified by Karl Fisher coulometric titration. Conclusively, advanced spray-drying particle engineering design from organic solution in closed mode was successfully used to design and optimize solid-state particles in the respirable size range necessary for targeted pulmonary delivery, particularly for the deep lung. These particles were dry, stable, and had optimal properties for dry powder inhalation as a novel pulmonary nanomedicine.