Rediscovering mycophenolic acid: a review of its mechanism, side effects, and potential uses

Protein sequence analysis in the context of drug repurposing

MOTIVATION

Drug repurposing speeds up the development of new treatments, being less costly, risky, and time consuming than de novo drug discovery. There are numerous biological elements that contribute to the development of diseases and, as a result, to the repurposing of drugs.

METHODS

In this article, we analysed the potential role of protein sequences in drug repurposing scenarios. For this purpose, we embedded the protein sequences by performing four state of the art methods and validated their capacity to encapsulate essential biological information through visualization. Then, we compared the differences in sequence distance between protein-drug target pairs of drug repurposing and non - drug repurposing data. Thus, we were able to uncover patterns that define protein sequences in repurposing cases.

RESULTS

We found statistically significant sequence distance differences between protein pairs in the repurposing data and the rest of protein pairs in non-repurposing data. In this manner, we verified the potential of using numerical representations of sequences to generate repurposing hypotheses in the future.

Apoptotic Janus-faced mycotoxins against thoracal and breast metastases

Abdominal organs (liver, kidney, spleen) are frequent targets of cancer cell invasion but their primary tumours are less known for their metastatic potential to other organs e.g. to the breast. Despite the known connection of the pathogenesis from breast cancer to liver metastasis, the study of the spread in the opposite direction has been neglected. The notion that breast cancer could be a metastasis besides being a primary tumour is based on rodents' tumour models upon implantation of tumour cells under the capsule of the kidney or under the Glisson's capsule of the liver of rats and mice. Tumour cells develop into a primary tumour at the site of subcutaneous implantation. The metastatic process starts with peripheral disruptions of blood vessels near the surface of primary tumours. Tumour cells released into the abdomen cross the apertures of the diaphragm, enter the thoracal lymph nodes and accumulate in parathymic lymph nodes. Abdominal colloidal carbon particles injected into the abdomen faithfully mimicked the migration of tumour cells and deposited in parathymic lymph nodes (PTNs). An explanation is provided why the connection between abdominal tumours and mammary tumours escaped attention, notably, parathymic lymph nodes in humans were referred to as internal mammary or parasternal lymph nodes. The apoptotic effect of Janus-faced cytotoxins is suggested to provide a new approach against the spread of abdominal primary tumours, and metastatic development.

Alteration of the gut microbiome in mycophenolate-induced enteropathy: impacts on the profile of short-chain fatty acids in a mouse model

BACKGROUND

Mycophenolic acid (MPA) is the most widely used immunosuppressive drug in transplantation and for autoimmune diseases. Unfortunately, more than 30% of patients experience a typical gastrointestinal adverse effect also referred to as mycophenolate-induced enteropathy. Due to its antibacterial, antifungal, and antiviral properties, MPA exposure is associated with intestinal dysbiosis characterized by a decrease in density and diversity of the microbiome regarding the main bacterial phyla (Firmicutes and Bacteroidetes). These bacterial phyla are known for their metabolic role in maintaining the homeostasis of the digestive tract, particularly through the production of short-chain fatty acids (SCFA) that could contribute to the pathophysiology of mycophenolate-induced enteropathy. Our study aimed at deciphering short-chain fatty acids (SCFA) profile alterations associated with gastrointestinal toxicity of MPA at the digestive and systemic levels in a mouse model.

METHODS

Ten-week old C57BL/6 (SOPF) mice were randomly assigned in 2 groups of 9 subjects: control, and mycophenolate mofetil (MMF, 900 mg/kg/day). All mice were daily treated by oral gavage for 7 days. Individual faecal pellets were collected at days 0, 4 and 8 as well as plasma at day 8 for SCFA profiling. Additionally, after the sacrifice on day 8, the caecum was weighted, and colon length was measured. The proximal colon was cut for histological analysis.

RESULTS

MMF treatment induced around 10% weight loss at the end of the protocol associated with a significant decrease in caecum weight and a slight reduction in colon length. Histological analysis showed significant architectural changes in colon epithelium. Moreover, we observed an overall decrease in SCFA concentrations in faecal samples, especially regarding acetate (at day 8, control 1040.6 ± 278.161 μM versus MMF 384.7 ± 80.5 μM, p < 0.01) and propionate (at day 8, control 185.94 ± 51.96 μM versus MMF 44.07 ± 14.66 μM, p < 0.001), and in plasma samples for butyrate (at day 8, control 0.91 ± 0.1 μM versus MMF 0.46 ± 0.1 μM, p < 0.01).

CONCLUSIONS

These results are consistent with functional impairment of the gut microbiome linked with digestive or systemic defects during MMF treatment.

Drug repurposing approach to combating coronavirus: Potential drugs and drug targets

In the past two decades, three highly pathogenic human coronaviruses severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus, and, recently, SARS-CoV-2, have caused pandemics of severe acute respiratory diseases with alarming morbidity and mortality. Due to the lack of specific anti-CoV therapies, the ongoing pandemic of coronavirus disease 2019 (COVID-19) poses a great challenge to clinical management and highlights an urgent need for effective interventions. Drug repurposing is a rapid and feasible strategy to identify effective drugs for combating this deadly infection. In this review, we summarize the therapeutic CoV targets, focus on the existing small molecule drugs that have the potential to be repurposed for existing and emerging CoV infections of the future, and discuss the clinical progress of developing small molecule drugs for COVID-19.

Polysaccharide mycophenolate-based nanoparticles for enhanced immunosuppression and treatment of immune-mediated inflammatory diseases

Immune-mediated inflammatory diseases (IMIDs) are characterized by immune dysregulation and severe inflammation caused by the aberrant and overactive host immunological response. Mycophenolic acid (MPA)-based immunosuppressive drugs are potential treatments for IMIDs because of their mild side-effect profile; however, their therapeutic effects are limited by the high albumin binding rate, unsatisfactory pharmacokinetics, and undefined cellular uptake selectivity.

Methods: Polysaccharide mycophenolate was synthesized by conjugating MPA molecules to dextran (a typical polysaccharide widely used in drug delivery) and encapsulated extra free MPA molecules to fabricate MPA@Dex-MPA nanoparticles (NPs). The efficacy of these NPs for mediating immunosuppression and treatment of IMIDs was evaluated in imiquimod-induced psoriasis-like skin inflammation in Balb/c mice, a representative IMID model.

Results: The MPA@Dex-MPA NPs exhibited high MPA loading efficiency, low albumin binding rates, and sustained MPA release, resulting in improved pharmacokinetics in vivo. Compared to free MPA, MPA@Dex-MPA NPs induced more robust therapeutic effects on IMIDs. Mechanistic studies indicated that MPA@Dex-MPA NPs were primarily distributed in dendritic cells (DCs) and significantly suppressed the overactivated DCs in vivo and in vitro. Furthermore, the recovered DCs rehabilitated the IL-23/Th17 axis function and significantly ameliorated imiquimod-induced psoriasis-like skin inflammation. Importantly, MPA@Dex-MPA NPs showed favorable safety and biocompatibility in vivo.

Conclusion: Our results indicated the polysaccharide mycophenolate-based NPs to be highly promising for IMID treatment.

Microbial Resistance Movements: An Overview of Global Public Health Threats Posed by Antimicrobial Resistance, and How Best to Counter

Antibiotics changed medical practice by significantly decreasing the morbidity and mortality associated with bacterial infection. However, infectious diseases remain the leading cause of death in the world. There is global concern about the rise in antimicrobial resistance (AMR), which affects both developed and developing countries. AMR is a public health challenge with extensive health, economic, and societal implications. This paper sets AMR in context, starting with the history of antibiotics, including the discovery of penicillin and the golden era of antibiotics, before exploring the problems and challenges we now face due to AMR. Among the factors discussed is the low level of development of new antimicrobials and the irrational prescribing of antibiotics in developed and developing countries. A fundamental problem is the knowledge, attitude, and practice (KAP) regarding antibiotics among medical practitioners, and we explore this aspect in some depth, including a discussion on the KAP among medical students. We conclude with suggestions on how to address this public health threat, including recommendations on training medical students about antibiotics, and strategies to overcome the problems of irrational antibiotic prescribing and AMR.

Eosinophilic granulomatosis with polyangiitis (EGPA) on remission with a new neuropathy: a rare case of mycophenolate induced primary CNS lymphoproliferative disease

Introduction

Mycophenolate Mofetil (MMF), although a widely used immunosuppressant; an increasing concern of MMF induced Primary Central Nervous System Lymphoma (PCNSL) are being reported. Timely diagnosis and management of MMF induced PCNSL can play a vital role in improved outcomes.

Case Presentation

Eighty-one-year-old female with history of Eosinophilic Granulomatosis with Polyangiitis (EGPA) presented with word finding difficulty, right-hand weakness and right foot clumsiness. EGPA had been stable with MMF for 6 years. Physical examination revealed weakened right-hand grip, positive right-sided dysdiadokokinesia and right foot drop. MRI-brain identified three enhancing solid lesions – in right parietal, left insular and left mid brain extending into the left thalamus. Brain biopsy revealed a focally dense lymphoid infiltrate with CD20 positive B cells, with large atypical cells resembling Hodgkin Reed-Sternberg cells. With concern for immunosuppression related PCNSL, MMF was stopped. Patient was treated with 8 weeks of rituximab therapy for its least toxic profile and concomitant benefit in EGPA. On a 2 month follow up MRI-brain, near total resolution of the intracranial lesion was observed. Patient still had some residual right lower extremity incoordination, however, strength and speech normalized with resolution of dysdiadokokinesia. Patient was advised to discontinue MMF indefinitely and remains on low dose prednisone daily.

Conclusion

MMF is an inhibitor of Inosine Monophosphate Dehydrogenase which prevents T- and B-cell proliferation. PCNSL is a potential complication of chronic immunosuppression with this medication. Discontinuation of the drug along with immunosuppressive therapies have been the effective therapeutic options till date.

The Next Frontier of Regulatory T Cells: Promising Immunotherapy for Autoimmune Diseases and Organ Transplantations

Regulatory T cells (Tregs) are crucial in maintaining tolerance. Hence, Treg immunotherapy is an attractive therapeutic option in autoimmune diseases and organ transplantations. Currently, autoimmune diseases do not have a curative treatment and transplant recipients require life-long immunosuppression to prevent graft rejection. There has been significant progress in understanding polyclonal and antigen-specific Treg biology over the last decade. Clinical trials with good manufacturing practice (GMP) Treg cells have demonstrated safety and early efficacy of Treg therapy. GMP Treg cells can also be tracked following infusion. In order to improve efficacy of Tregs immunotherapy, it is necessary that Tregs migrate, survive and function at the specific target tissue. Application of antigen specific Tregs and maintaining cells' suppressive function and survival with low dose interleukin-2 (IL-2) will enhance the efficacy and longevity of infused GMP-grade Tregs. Notably, stability of Tregs in the local tissue can be manipulated by understanding the microenvironment. With the recent advances in GMP-grade Tregs isolation and antigen-specific chimeric antigen receptor (CAR)-Tregs development will allow functionally superior cells to migrate to the target organ. Thus, Tregs immunotherapy may be a promising option for patients with autoimmune diseases and organ transplantations in near future.

Effective delivery of mycophenolic acid by oxygen nanobubbles for modulating immunosuppression

Immunosuppressive drugs are crucial for preventing acute graft rejection or autoimmune diseases. They are generally small molecules that require suitable drug carriers for ensuring stability, bioavailability, and longer half-life. Mycophenolic acid (MPA) is an extensively studied immunosuppressive drug. However, it requires suitable carriers for overcoming clinical limitations. Currently, lipid-shelled micro- and nanobubbles are being thoroughly investigated for diagnostic and therapeutic applications, as they possess essential properties, such as injectability, smaller size, gaseous core, high surface area, higher drug payload, and enhanced cellular penetration. Phospholipids are biocompatible and biodegradable molecules, and can be functionalized according to specific requirements.

Methods: In this study, we synthesized oxygen nanobubbles (ONBs) and loaded the hydrophobic MPA within the ONBs to generate ONB/MPA. Peripheral blood mononuclear cells (PBMCs) were treated with ONB/MPA to determine the suppression of immune response by measuring cytokine release. In vivo murine experiments were performed to evaluate the effectiveness of ONB/MPA in the presence of inflammatory stimulants.

Results: Our results suggest that ONBs successfully delivered MPA and reduced the release of cytokines, thereby controlling inflammation and significantly increasing the survival rate of animals.

Conclusion: This method can be potentially used for implantation and for treating autoimmune diseases, wherein immunosuppression is desired.

Environmental Risk Assessment for the Active Pharmaceutical Ingredient Mycophenolic Acid in European Surface Waters

An environmental risk assessment is presented for mycophenolic acid (MPA), an immunosuppressive pharmaceutical used for prevention of organ rejection, and its prodrug mycophenolate mofetil (MPM). Mycophenolic acid will not significantly adsorb to activated sludge. In activated sludge, ¹⁴ C-MPA attained >80% degradation, supporting an older environmental fate test with the same compound. Based on n-octanol/water distribution coefficient (log D_OW ) values of 2.28, 0.48, and ≤-1.54 at pH 5, 7, and 9, respectively, MPA is not expected to bioaccumulate. Sales amounts of MPA+MPM in Europe were used to derive predicted environmental concentrations (PECs) in surface waters; PECs were refined by including expected biodegradation in sewage treatment, average drinking water use, and average dilution of the effluents in the receiving waters per country. In addition, the exposure to pharmaceuticals in the environment (ePiE) model was run for 4 European catchments. The PECs were complemented with 110 measured environmental concentrations (MECs), ranging from below the limit of quantitation (<0.001 µg/L) to 0.656 µg/L. Predicted no-effect concentrations (PNECs) were derived from chronic tests with cyanobacteria, green algae, daphnids, and fish. The comparison of PECs and MECs with the PNECs resulted in a differentiated environmental risk assessment in which the risk ratio of PEC/PNEC or MEC/PNEC was <1 in most cases (mostly >90%), meaning no significant risk, but a potential risk to aquatic organisms in generally <10% of instances. Because this assessment reveals a partial risk, the following questions must be asked: How much risk is acceptable? and Through which measures can this risk be reduced? These questions are all the more important in view of limited alternatives for MPM and MPA and the serious consequences of not using them. Environ Toxicol Chem 2019;38:2259-2278. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Pharmacogenetics: A strategy for personalized medicine for autoimmune diseases

For many years, a considerable number of patients with autoimmune diseases (ADs) have suffered from a lack of drug response and drug-related toxicity. Despite the emergence of new therapeutic options such as biological agents, patients continue to struggle with these problems. Unfortunately, new challenges, including the paradoxical effects of biological drugs, have complicated the situation. In recent decades, efforts have been made to predict drug response as well as drug-related side effects. Thanks to the many advances in genetics, evaluation of markers to predict drug response/toxicity before the initiation of treatment may be an avenue toward personalizing treatments. Implementing pharmacogenetics and pharmacogenomics in the clinic could improve clinical care; however, obstacles remain to effective personalized medicine for ADs. The present study attempted to clarify the concept of pharmacogenetics/pharmacogenomics for ADs. After an overview on the pathogenesis of the most common types of treatments, this paper focuses on pharmacogenetic studies related to the selected ADs. Bridging the gap between pharmacogenetics and personalized medicine is also discussed. Moreover, the advantages, disadvantages and recommendations related to making personalized medicine practical for ADs have been addressed.

Levamisole in Children with Idiopathic Nephrotic Syndrome: Clinical Efficacy and Pathophysiological Aspects

Steroid sensitive nephrotic syndrome is one of the most common pediatric glomerular diseases. Unfortunately, it follows a relapsing and remitting course in the majority of cases, with 50% of all cases relapsing once or even more often. Most children with idiopathic nephrotic syndrome respond initially to steroid therapy, nevertheless repeated courses for patients with relapses induce significant steroid toxicity. Patients with frequent relapses or steroid dependency thus require alternative treatment, such as cyclophosphamide, cyclosporine, tacrolimus, mycophenolate mofetil, levamisole, or rituximab. To reduce the relapse rate, several drugs have been used. Among these, levamisole has been considered the least toxic and least expensive therapy. Several randomized controlled trials (RCT) showed that levamisole is effective in reducing the relapse risk in steroid sensitive forms of nephrotic syndrome with a low frequency of side effects. Levamisole is a synthetic imidazothiazole derivative with immune-modulatory properties. In this article, we review recent data from randomized trials and observational studies to assess the efficacy of levamisole in frequently relapsing nephrotic syndrome and steroid-dependent nephrotic syndrome.

Transplant immunosuppressive drugs in urology

Immunosuppressive drugs are used in renal transplantation to prevent and treat rejection and their use has traditionally been limited to urologists trained in transplant surgery. However, there are other urologic conditions for which these drugs have proven efficacy. Since transplant surgery has become a small niche subspecialty within urology, most urologists are unfamiliar and uncomfortable with their use. This review will focus on the use of Cyclosporine (CyA), mycophenolate mofetil (MMF), and mammalian target of rapamycin (mTOR) inhibitors in urology outside of solid organ transplant. This includes the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) with CyA as well as the role of CyA in eosinophilic cystitis (EC) and the treatment of retroperitoneal fibrosis (RF) with MMF. Also included is the utilization of mTOR inhibitors in both advanced renal cell carcinoma (RCC) and in patients with tuberous sclerosis complex (TSC) associated angiomyolipoma (AML). Available clinical data on mTOR inhibition in autosomal dominant polycystic kidney disease (ADPKD) is also briefly presented. Specific attention is given to the indications for each agent, the available evidence surrounding their use, and the most common adverse events (AEs) and their subsequent management.

Synthesis and antimicrobial activity of amino acid and peptide derivatives of mycophenolic acid

The series of 16 novel amino acid and peptide mycophenolic acid (MPA) derivatives was obtained as potential antibacterial agents. Coupling of MPA with respective amines was optimized with condensing reagents such as EDCI/DMAP and T3P/TEA. Amino acid analogs were received both as methyl esters and also with the free carboxylic group. The biological activity of the products was tested on five references bacterial strains: Klebsiella pneumoniae ATCC 700603 (ESBL), Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus MRSA ATCC 43300, Staphylococcus aureus MSSA ATCC 25923. Peptide derivatives proved to be the most versatile ones, their MIC values relative to most strains was lower than MPA alone. It has been noted that the activity of amino acid derivatives depends on the configuration at the chiral center in the amino acid unit and methyl esters indicated better antimicrobial activity than analogs with free carboxylic group.

Middle East Respiratory Syndrome and Severe Acute Respiratory Syndrome: Current Therapeutic Options and Potential Targets for Novel Therapies

No specific antivirals are currently available for two emerging infectious diseases, Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS). A literature search was performed covering pathogenesis, clinical features and therapeutics, clinically developed drugs for repurposing and novel drug targets. This review presents current knowledge on the epidemiology, pathogenesis and clinical features of the SARS and MERS coronaviruses. The rationale for and outcomes with treatments used for SARS and MERS is discussed. The main focus of the review is on drug development and the potential that drugs approved for other indications provide for repurposing. The drugs we discuss belong to a wide range of different drug classes, such as cancer therapeutics, antipsychotics, and antimalarials. In addition to their activity against MERS and SARS coronaviruses, many of these approved drugs have broad-spectrum potential and have already been in clinical use for treating other viral infections. A wealth of knowledge is available for these drugs. However, the information in this review is not meant to guide clinical decisions, and any therapeutic described here should only be used in context of a clinical trial. Potential targets for novel antivirals and antibodies are discussed as well as lessons learned from treatment development for other RNA viruses. The article concludes with a discussion of the gaps in our knowledge and areas for future research on emerging coronaviruses.

One-pot borylation/Suzuki-Miyaura sp2-sp3 cross-coupling

We describe the first one-pot borylation/Suzuki-Miyaura sp²-sp³ cross-coupling between readily available aryl (pseudo)halides and activated alkyl chlorides. This method streamlines the synthesis of diaryl methanes, α-aryl carbonyls and allyl aryl compounds, substructures that are commonly found in life changing drug molecules.

Systemic therapy of atopic dermatitis

Therapy of severe atopic dermatitis, which is refractory to consistent treatment with topical steroids and topical calcineurin inhibitors is still a problem in many cases. The use of cyclosporine, which is the only approved systemic drug for the therapy of severe atopic dermatitis, is often limited by contraindications or adverse reactions. In this context, results from controlled and open-label studies with novel therapeutic approaches such as methotrexate, omalizumab or rituximab, which are in part very promising, are of great interest. In this work we would like to provide an overview of established and new therapeutic options for the treatment of severe atopic dermatitis.

Antiviral screening identifies adenosine analogs targeting the endogenous dsRNA Leishmania RNA virus 1 (LRV1) pathogenicity factor

The endogenous double-stranded RNA (dsRNA) virus Leishmaniavirus (LRV1) has been implicated as a pathogenicity factor for leishmaniasis in rodent models and human disease, and associated with drug-treatment failures in Leishmania braziliensis and Leishmania guyanensis infections. Thus, methods targeting LRV1 could have therapeutic benefit. Here we screened a panel of antivirals for parasite and LRV1 inhibition, focusing on nucleoside analogs to capitalize on the highly active salvage pathways of Leishmania, which are purine auxotrophs. Applying a capsid flow cytometry assay, we identified two 2'-C-methyladenosine analogs showing selective inhibition of LRV1. Treatment resulted in loss of LRV1 with first-order kinetics, as expected for random virus segregation, and elimination within six cell doublings, consistent with a measured LRV1 copy number of about 15. Viral loss was specific to antiviral nucleoside treatment and not induced by growth inhibitors, in contrast to fungal dsRNA viruses. Comparisons of drug-treated LRV1⁺ and LRV1^- lines recapitulated LRV1-dependent pathology and parasite replication in mouse infections, and cytokine secretion in macrophage infections. Agents targeting Totiviridae have not been described previously, nor are there many examples of inhibitors acting against dsRNA viruses more generally. The compounds identified here provide a key proof-of-principle in support of further studies identifying efficacious antivirals for use in in vivo studies of LRV1-mediated virulence.

Biofilm inhibitors targeting the outer membrane protein A of Pasteurella multocida in swine

Pasteurella multocida (Pm) is the causative agent of atrophic rhinitis in swine. This study aimed to discover biofilm inhibitors against swine Pm to counteract antibiotic resistance and decrease virulence. The virulence factor outer membrane protein A (OmpA) was targeted. A library of drugs approved by the Food and Drug Administration (FDA) was used to perform virtual screening against PmOmpA. The top-scoring compounds had no effect on the growth of Pm serotype A or D. Mycophenolate mofetil showed the highest efficacy in inhibiting biofilm formation by Pm serotype A, with an IC₅₀ of 7.3 nM. For Pm serotype D, indocyanine green showed the highest effect at an IC₅₀ of 11.7 nM. Nevertheless, these compounds had no effect on an established biofilm of Pm. This study offers an alternative way to prevent biofilm formation by Pm that could also be applied to other pathogens.

Impact of Immune-Modulatory Drugs on Regulatory T Cell

Immunosuppression strategies that selectively inhibit effector T cells while preserving and even enhancing CD4FOXP3 regulatory T cells (Treg) permit immune self-regulation and may allow minimization of immunosuppression and associated toxicities. Many immunosuppressive drugs were developed before the identity and function of Treg were appreciated. A good understanding of the interactions between Treg and immunosuppressive agents will be valuable to the effective design of more tolerable immunosuppression regimens. This review will discuss preclinical and clinical evidence regarding the influence of current and emerging immunosuppressive drugs on Treg homeostasis, stability, and function as a guideline for the selection and development of Treg-friendly immunosuppressive regimens.

Production of mycophenolic acid by Penicillium brevicompactum-A comparison of two methods of optimization

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Medium optimization for MPA production using P. brevicompactum by one-factor-at-a-time and CCD methods.

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CCD afforded a 40% higher MPA titer than one-factor-at-a-time method.

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The titer was nearly 6-fold higher compared to un-optimized medium.

Production of mycophenolic acid (MPA) by submerged fermentation using the microfungus Penicillium brevicompactum MTCC 8010 is reported here. Screening experiments were used to identify: the suitable media composition; the optimal initial pH; and the optimal incubation temperature to maximize the production of MPA in batch cultures. The initial concentrations of the selected sources of carbon (glucose), nitrogen (peptone) and the precursors (methionine, glycine) were then optimized by: (1) one-at-a-time variation of factors; and (2) a central composite design (CCD) of experiments, in a 12-day batch culture at an initial pH of 5.0, an incubation temperature of 25 °C, and an agitation speed of 200 rpm. The medium optimized using the one-at-a-time variation yielded a peak MPA titer of 1232 ± 90 mg/L. The medium optimized by the CCD method yielded a 40% higher MPA titer of 1737 ± 55 mg/L. The latter value was nearly 9-fold greater than the titer achieved prior to optimization.

Enhancement of Mycophenolate Mofetil Permeation for Topical Use by Eucalyptol and N-Methyl-2-pyrrolidone

Mycophenolate mofetil (MMF) is a prodrug of mycophenolic acid (MPA) which can be metabolized by esterase. MMF has been approved by the United States Food and Drug Administration (USFDA) for treatment of psoriasis patient with skin symptoms. However, it remains unclear whether MMF is efficiently effective to treat skin symptoms developed from psoriasis. The insufficient amount of MMF penetrating through the skin results in the treatment failure due to the difficulty in MMF penetration through the stratum corneum. Skin permeation enhancers such as eucalyptol (EUL) and N-methyl-2-pyrrolidone (NMP) potentially aid in increasing skin penetration. This study aimed to investigate the effects of a concentration ratio (% w/v) between two enhancers (EUL and NMP). The results showed that EUL enhanced MMF permeation with an enhancement ratio (ER) of 3.44 while NMP was not able to promote the penetration of MMF. Interestingly, the synergistic effect of the two enhancers was observed with a suitable ratio given that the ER was 8.21. EUL and NMP are promising enhancers for the development of MMF based skin product.

A septin requirement differentiates autonomous and contact-facilitated T cell proliferation

T cell proliferation is initiated by T cell antigen receptor (TCR) triggering and/or by soluble growth factors. In characterizing T cells lacking the septin cytoskeleton, we found that successful cell division has discrete septin-dependent and -independent pathways. Septin-deficient T cells failed cytokinesis when prompted by pharmacological activation or cytokines. In contrast, cell division was independent of septins when cell-cell contacts, such as those from antigen-presenting cells, provided a niche. This septin-independent pathway was mediated by phosphatidylinositol-3-OH kinase activation through a combination of integrins and co-stimulatory signals. We could differentiate cytokine- versus antigen-driven expansion in vivo and thus demonstrate that targeting septins has strong potential to moderate detrimental bystander or homeostatic cytokine-driven proliferation without influencing expansion driven by conventional antigen-presentation.

Adenylosuccinate Is an Insulin Secretagogue Derived from Glucose-Induced Purine Metabolism

Pancreatic islet failure, involving loss of glucose-stimulated insulin secretion (GSIS) from islet β cells, heralds the onset of type 2 diabetes (T2D). To search for mediators of GSIS, we performed metabolomics profiling of the insulinoma cell line 832/13 and uncovered significant glucose-induced changes in purine pathway intermediates, including a decrease in inosine monophosphate (IMP) and an increase in adenylosuccinate (S-AMP), suggesting a regulatory role for the enzyme that links the two metabolites, adenylosuccinate synthase (ADSS). Inhibition of ADSS or a more proximal enzyme in the S-AMP biosynthesis pathway, adenylosuccinate lyase, lowers S-AMP levels and impairs GSIS. Addition of S-AMP to the interior of patch-clamped human β cells amplifies exocytosis, an effect dependent upon expression of sentrin/SUMO-specific protease 1 (SENP1). S-AMP also overcomes the defect in glucose-induced exocytosis in β cells from a human donor with T2D. S-AMP is, thus, an insulin secretagogue capable of reversing β cell dysfunction in T2D.

Antiviral drug discovery: broad-spectrum drugs from nature

Covering: up to April 2014. The development of drugs with broad-spectrum antiviral activities is a long pursued goal in drug discovery. It has been shown that blocking co-opted host-factors abrogates the replication of many viruses, yet the development of such host-targeting drugs has been met with scepticism mainly due to toxicity issues and poor translation to in vivo models. With the advent of new and more powerful screening assays and prediction tools, the idea of a drug that can efficiently treat a wide range of viral infections by blocking specific host functions has re-bloomed. Here we critically review the state-of-the-art in broad-spectrum antiviral drug discovery. We discuss putative targets and treatment strategies, with particular focus on natural products as promising starting points for antiviral lead development.

Mycophenolate Mofetil as an Adjuvant Therapy for Classic and Endemic Pemphigus Foliaceus

Pemphigus foliaceus is an autoimmune cutaneous disease with subcorneal acantholysis and pathogenic IgG4 autoantibodies directed against desmoglein 1. We present our experience with mycophenolate mofetil (MMF) in the treatment of one case of endemic pemphigus foliaceus (fogo selvagem) and two cases of the classic form. All patients had severe, refractory disease and developed marked adverse effects due to long-term corticosteroid therapy. MMF proved to be an effective corticosteroid-sparing agent at doses varying from 35 to 45 mg/kg/d. It was well tolerated, and we found no significant adverse effects from this drug.

Antiviral perspectives for chikungunya virus

Chikungunya virus (CHIKV) is a mosquito-borne pathogen that has a major health impact in humans and causes acute febrile illness in humans accompanied by joint pains and, in many cases, persistent arthralgia lasting for weeks to years. CHIKV reemerged in 2005-2006 in several parts of the Indian Ocean islands and India after a gap of 32 years, causing millions of cases. The re-emergence of CHIKV has also resulted in numerous outbreaks in several countries in the eastern hemisphere, with a threat to further expand in the near future. However, there is no vaccine against CHIKV infection licensed for human use, and therapy for CHIKV infection is still mainly limited to supportive care as antiviral agents are yet in different stages of testing or development. In this review we explore the different perspectives for chikungunya treatment and the effectiveness of these treatment regimens and discuss the scope for future directions.

Acute mycophenolate overdose: case series and systematic literature analysis

BACKGROUND

Literature regarding acute human toxicity of mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS) is limited.

OBJECTIVES

Our objectives were to describe all cases of overdose with MMF or EC-MPS reported to the Swiss Toxicological Information Centre (STIC) or in the literature between 1995 and 2013. Therefore, we performed an observational case-series and systematic literature search to determine circumstances, magnitude, management and outcome of overdose with MMF or EC-MPS.

RESULTS

Of 152,762 reports to STIC, 15 (7 pediatric) involved overdose with MMF (n = 13) or EC-MPS (n = 2). Three cases from other centers were identified from a systematic literature search. The magnitude of overdose ranged from 1.2 to 16.7 (median 2.9) times usual dose. Six (33%) MMF overdoses had attributable symptoms, which included abdominal pain, vomiting, headache and dizziness. The majority of findings were minor, although a 9-fold MMF overdose caused hypotension 8 h after ingestion and a 12.5-fold overdose caused leukopenia after 5 days. Symptoms did not occur in patients who took 2.5 times or less of their usual MMF dose. Gastrointestinal decontamination measures with activated charcoal were undertaken in one-third of cases.

CONCLUSIONS

Acute MMF and EC-MPS overdoses had a favorable outcome in all cases reported to STIC and in the literature.

Homeostatic T cell proliferation after islet transplantation

Pancreatic islet transplantation in patients with type 1 diabetes mellitus is performed under immunosuppression to avoid alloreactive T cell responses and to control the reactivation of autoreactive memory T cells. However, lymphopenia associated with immunosuppression and T cell depletion can induce a paradoxical expansion of lymphocyte subsets under the influence of homeostatic proliferation. Homeostatic T cell proliferation is mainly driven by the IL-7/IL-7 receptor axis, a molecular pathway which is not affected by standard immune-suppressive drugs and, consequently, represents a novel potential target for immuno-modulatory strategies. In this review, we will discuss how homeostatic T cell proliferation can support autoimmunity recurrence after islet transplantation and how it can be targeted by new therapeutic approaches.

Mycophenolic acid affects basic functions of human keratinocytes in the IMPDH-dependent manner

Clinical studies suggest that the immunosuppressant MPA is associated with impaired wound healing. It is believed that the main cause of impairment is the inhibition of inflammatory response. However, it is unknown whether MPA may directly affect epidermal cells. The aim of our study was to examine the direct influence of mycophenolic acid, the selective blocker of de novo purine synthesis, on human epidermal keratinocyte morphology, proliferation, motile activity, and differentiation in in vitro culture. The number of keratinocytes cultured in the presence of MPA was counted and cell motility was measured by a time-lapse computer-aided method. Cell morphology was determined by flow and image cytometry methods. Real-time RT-PCR analysis was employed to investigate the expression of markers of differentiation. We showed that MPA induces irreversible inhibition of cell proliferation, causes cell enlargement and impairs cell locomotion in a time-dependent manner. The level of expression of differentiation markers was significantly reduced by MPA treatment. All these effects were reversed by the addition of guanine. Our results indicated that MPA impairs basic functions of human skin keratinocytes via intracellular guanosine nucleotide depletion, which may be directly reflected in wound healing problems in patients treated with this immunosuppressant.

Inhibition of Junin virus RNA synthesis by an antiviral acridone derivative

There are no specific approved drugs for the treatment of agents of viral hemorrhagic fevers (HF) and antiviral therapies against these viruses are urgently needed. The present study characterizes the potent and selective antiviral activity against the HF causing arenavirus Junin virus (JUNV) of the compound 10-allyl-6-chloro-4-methoxy-9(10H)-acridone, designated 3f. The effectiveness of 3f to inhibit JUNV multiplication was not importantly affected by the initial multiplicity of infection, with similar effective concentration 50% (EC(50)) values in virus yield inhibition assays performed in Vero cells in the range of 0.2-40 plaque forming units (PFU)/cell. Mechanistic studies demonstrated that 3f did not affect the initial steps of adsorption and internalization. The subsequent process of viral RNA synthesis was strongly inhibited, as quantified by real time RT-PCR in compound-treated cells relative to non-treated cells. The addition of exogenous guanosine rescued the infectivity and RNA synthesis of JUNV in 3f-treated cells in a dose-dependent manner, but the reversal was partial, suggesting that the reduction of the GTP pool contributed to the antiviral activity of 3f, but it was not the main operative mechanism. The comparison of 3f with two other viral RNA inhibitors, ribavirin and mycophenolic acid, showed that ribavirin did not act against JUNV through the cellular enzyme inosine monophosphate dehydrogenase (IMPDH) inhibition whereas the anti-JUNV activity of mycophenolic acid was mainly targeted at this enzyme.

Mycophenolate mofetil-induced pseudotumor cerebri in a boy with autoimmune lymphoproliferative disease

INTRODUCTION

Pseudotumor cerebri (PTC) is a syndrome characterized with increased intracranial pressure, normal cerebrospinal fluid content (CSF), and a normal brain on imaging studies. In this case report, PTC has been linked to mycophenolate mofetil (MMF) that has been used for autoimmune lymphoproliferative syndrome (ALPS).

CASE REPORT

A 5-year-old boy, who was using MMF for 4 months because of the ALPS, suffered from occipital headache and vomiting with no other symptom. The initial physical examination was normal expect bilateral papilledema. The patient underwent a lumbar puncture which showed elevated opening pressure (590 mmH₂O) but no laboratory abnormalities of the CSF. A diagnosis of PTC was established. MMF was stopped, and the child was started on an acetazolamide treatment for 2 weeks. His symptoms and complaints recovered after this treatment.

DISCUSSION

According to our knowledge, we report the first case of MMF-induced PTC in a boy with ALPS. This case illustrates that despite the rarity of MMF-induced PTC, the physicians should be aware of this possibility. Furthermore, in the setting of new-onset headaches or visual changes, early ophthalmologic examination for papilledema is recommended for early diagnosis.

Review article: the role of non-biological drugs in refractory inflammatory bowel disease

BACKGROUND

Up to one-third of patients with inflammatory bowel disease (IBD) do not respond to, or are intolerant of conventional immunosuppressive drugs. Although biological agents are alternative treatments, they may not be suitable or available to some patients.

AIM

To review the evidence for use of nonbiological drugs in the treatment of patients with IBD refractory to corticosteroids or thiopurines.

METHODS

A literature search was performed using PubMed for English language publications with predetermined search criteria to identify relevant studies.

RESULTS

Published evidence from uncontrolled series and controlled clinical trials has been used to produce a practical approach relevant to clinical practice which incorporates the indication, optimal dose, and side effects of various therapies including tacrolimus, methotrexate, thalidomide, tioguanine, mycophenolate mofotil, leucocyte apheresis, nutritional therapy, antibiotics, probiotics, allopurinol, rectal acetarsol and ciclosporin in the treatment of patients with refractory ulcerative colitis and Crohn's disease. Approaches to optimise thiopurine efficacy are also discussed.

CONCLUSIONS

Patients with IBD refractory to corticosteroids or thiopurines may respond to alternative anti-inflammatory chemical molecules, but the evidence base for many of these alternatives is limited and further trials are needed.

Pharmacokinetic evaluation of mycophenolate mofetil for pemphigus

INTRODUCTION

Pemphigus is an autoimmune blistering disease of the skin and mucous membranes characterized by the development of autoantibodies against the desmosomal proteins, desmoglein-1 and -3. Before the advent of corticosteroids, therapy was almost fatal. The introduction of high-dose corticosteroid therapy has reduced mortality rates to ∼ 10%, but long-term use of steroids can lead to side effects, many of which are severe and associated with significant morbidity. Thus, the major goal of pemphigus therapy has been to reduce the patient's cumulative exposure to systemic corticosteroids. Over the last 2 decades, a range of corticosteroid-sparing immunosuppressive agents have been described, but these therapies are not without potentially serious complications. Despite the range of treatment options, a proportion of patients do not achieve remission, while others show an initial treatment response but remain poorly controlled. The recent availability of mycophenolate mofetil (MMF), originally developed for preventing allograft rejection, appears to be effective in autoimmune blistering diseases in combination with systemic corticosteroid or as a monotherapy.

AREAS COVERED

This review aims to provide an extensive overview of the literature on the clinical pharmacokinetics of MMF in pemphigus treatment and a brief summary of current pharmacodynamic information. After completing this learning activity, readers should be able to summarize the pharmacology of MMF as an immunosuppressant; recognize its potential role in the treatment of pemphigus, including general dosing guidelines and laboratory monitoring schedules, use in patient populations and potential adverse effects; and identify future considerations and developing areas of research regarding the use of mycophenolic acid in the treatment of autoimmune blistering diseases.

EXPERT OPINION

Current morbidity of pemphigus is largely iatrogenic, caused by side effects of the long-term, high-dose corticosteroid therapy that is necessary to sustain disease control. MMF demonstrates complex pharmacokinetics and displays large between-subject pharmacokinetic variability. Experience with MMF has demonstrated long-term safety and tolerability in the treatment of pemphigus.

Cellular IMPDH enzyme activity is a potential target for the inhibition of Chikungunya virus replication and virus induced apoptosis in cultured mammalian cells

Inosine monophosphate dehydrogenase (IMPDH) catalyzes an essential step in the de novo biosynthesis of guanine nucleotide, namely, the conversion of IMP to XMP. The depletion of the intracellular GTP and dGTP pools is the major event occurring in the cells exposed to the inhibitors such as mycophenolic acid. The present study was undertaken with an objective to assess the antiviral potential of mycophenolic acid (MPA) against Chikungunya virus via inhibition of IMPDH enzyme in Vero cells. The inhibitory potential of MPA on CHIKV replication was assessed by virus inhibition assay (cytopathic effect, immunofluorescence), virus yield reduction assay and cell viability assay. Inhibition of virus induced apoptosis was analyzed by Hoechst staining, DNA fragmentation, immunoblotting of Caspase-3, PARP and Bcl-2. Percentage apoptotic cell population was determined by flow cytometry. Total genome infectivity was determined by analyzing the ratio of total infectious viral particles to the genome copy number. Non-toxic concentration of MPA (10 μM) reduced ≥ 99.9% CHIKV titre in Vero cells. MPA via depletion of substrate for polymerase (GTP), inhibited CHIKV induced apoptosis. By limiting the rate of de novo synthesis of guanosine nucleotide, MPA could apparently block the formation of the CHIKV progeny. The antiviral activity of MPA against Chikungunya virus is mediated through depletion of GTP pool via inhibition of IMPDH as demonstrated by Immunoblotting and different microscopic analysis.

[Human papillomavirus-associated warts in organ transplant recipients. Incidence, risk factors, management]

Human papillomaviruses infect the squamous epithelia of the skin and cause warts, and are occasionally found in squamous cell carcinomas. Since cell-mediated immunity plays a crucial role in the control of HPV-infections, organ transplant recipients, unable to mount an adequate T-helper 1 cell-mediated immune surveillance, frequently develop widespread and resistant induced warts. Skin tumors, especially squamous cell carcinomas, are the most common post-transplantation neoplasm. Warts, actinic keratoses and invasive squamous cell carcinomas are known to develop at the same time in the areas. The role of HPV in the development of invasive squamous cell carcinoma under immunosuppression, remains to be elucidated in respect to common risk factors and increased numbers of warts potentially identifying patients at increased risk for carcinoma. We prospectively studied 1690 organ transplant recipients in the dermatology clinic at the Charité University Hospital in Berlin, to evaluate risk factors being involved in the development of HPV-induced warts and to assess a potential association of with the development of non-melanoma skin cancers in this population. The cumulative incidence of warts steadily increased throughout the post-transplant years. The presence of more than 10 verrucae was associated with the development of actinic keratoses, invasive squamous cell carcinoma and basal cell carcinoma. This study shows clear evidence that certain risk factors of skin carcinogenesis in organ transplant recipient such as increased age at transplantation, a high dose of immunosuppression related to a specific type of graft and use of azathioprine or cyclosporine are strongly associated with an increased incidence of warts. Furthermore, HPV-induced verrucae vulgares could be used as a potential predictor for the development of coincidental non melanoma skin cancer in organ transplant recipients and therefore could serve as an early identification marker of skin cancer high-risk patients. The challenging management of warts in organ transplantation patients is reviewed.

New pathophysiological insights and modern treatment of IBD

Inflammatory bowel disease (IBD), which comprises two main types, namely, Crohn's disease and ulcerative colitis, affects approximately 3.6 million people in the USA and Europe, and an alarming rise in low-incidence areas, such as Asia, is currently being observed. In the last decade, spontaneous mutations in a diversity of genes have been identified, and these have helped to elucidate pathways that can lead to IBD. Animal studies have also increased our knowledge of the pathological dialogue between the intestinal microbiota and components of the innate and adaptive immune systems misdirecting the immune system to attack the colon. Present-day medical therapy of IBD consists of salicylates, corticosteroids, immunosuppressants and immunomodulators. However, their use may result in severe side effects and complications, such as an increased rate of malignancies or infectious diseases. In clinical practice, there is still a high frequency of incomplete or absent response to medical therapy, indicating a compelling need for new therapeutic strategies. This review summarizes current epidemiology, pathogenesis and diagnostic strategies in IBD. It also provides insight in today's differentiated clinical therapy and describes mechanisms of promising future medicinal approaches.

Effect of the inosine 5'-monophosphate dehydrogenase inhibitor BMS-566419 on rat cardiac allograft rejection

Inosine 5'-monophosphate dehydrogenase (IMPDH) inhibition is a critical target in solid organ transplantation, and the development of mycophenolate mofetil (MMF) represents a major advance in transplant medicine. In this study, the in vitro and in vivo pharmacological effects of BMS-566419, a novel chemically synthesized IMPDH inhibitor, were compared to those of mycophenolic acid (MPA) and MMF based on results from several immunological experiments. The in vitro inhibitory activity of BMS-566419 on IMPDH type I/II, immune cell proliferation and antibody production from lipopolysaccharide (LPS)-stimulated B cells was similar, albeit slightly less potent than that of MPA. In a rat heterotopic cardiac transplant model, monotherapy using orally administered BMS-566419 60mg/kg or MMF 40mg/kg prolonged the median survival time (MST) of transplanted grafts in the vehicle group from 5 to 18 and 18.5 days, respectively. In the presence of a sub-therapeutic dose of FK506, BMS-566419 30mg/kg and MMF 20mg/kg showed identical efficacy with an MST of 21.5 days. In dinitrophenol-LPS-stimulated rats in which calcineurin inhibitors failed to inhibit antibody production, in vivo oral administration of BMS-566419 resulted in antibody production suppression with similar efficacy to MMF. The in vivo antibody production against alloantigen was also suppressed by MMF or BMS-566419 treatment. In addition, gastrointestinal toxicity, considered a dose-limiting factor of MMF, was reduced in BMS-566419 treatment. These results suggest that BMS-566419 and other chemically synthesized IMPDH inhibitors have beneficial pharmacological effects similar to those of MMF, and are potential pharmaceutical candidates in transplant indications.

Mycophenolate in dermatology

Originally used to treat psoriasis nearly three decades ago, mycophenolic acid, reformulated as mycophenolate mofetil (MMF), has been rediscovered by the world of dermatology. As a relatively well-tolerated immunosuppressive used in organ transplant recipients, MMF has recently been reported to show promise for several dermatologic conditions, including psoriasis, pemphigus vulgaris, pyoderma gangrenosum, bullous lichen planus, and even connective tissue diseases such as lupus erythematosus and dermatomyositis. Although not intended to be exhaustive, this review discusses MMF with regard to its basic pharmacology, its side effects, and its reported efficacy in a variety of dermatologic indications. Relevant literature was retrieved by a Medline search combining the terms "mycophenolate" or "mycophenolic acid" and "skin" or "skin disease" or a number of specific conditions ("psoriasis", "dermatitis", "eczema", "pemphigoid", "pemphigus", "vasculitis", "pyoderma gangrenosum", "Crohn's disease", "graft-versus-host disease", "lichen planus"). As MMF has only been recently re-introduced for dermatologic application, the nature of much of the literature is admittedly that of case reports or case series. Nevertheless, the results are sufficiently promising to warrant further larger, control studies.

Mycophenolate mofetil in pyoderma gangrenosum

Recently, the use of mycophenolate mofetil (MMF) has expanded in dermatological practice. Three patients with PG received MMF in conjunction with prednisone and a fourth patient received MMF monotherapy daily. MMF in combination with prednisone in three of our patients and alone in our fourth patient induced healing of their ulcers. The first patient tolerated MMF apart from gastrointestinal upset, while treatment in our second patient was complicated by staphylococcal and pseudomonal sepsis. The third patient complained of palpitations and headaches.