Mycophenolate mofetil and its mechanisms of action

Comprehensive review for anticancer hybridized multitargeting HDAC inhibitors

Despite the encouraging clinical progress of chemotherapeutic agents in cancer treatment, innovation and development of new effective anticancer candidates still represents a challenging endeavor. With 15 million death every year in 2030 according to the estimates, cancer has increased rising of an alarm as a real crisis for public health and health systems worldwide. Therefore, scientist began to introduce innovative solutions to control the cancer global health problem. One of the promising strategies in this issue is the multitarget or smart hybrids having two or more pharmacophores targeting cancer. These rationalized hybrid molecules have gained great interests in cancer treatment as they are capable to simultaneously inhibit more than cancer pathway or target without drug-drug interactions and with less side effects. A prime important example of these hybrids, the HDAC hybrid inhibitors or referred as multitargeting HDAC inhibitors. The ability of HDAC inhibitors to synergistically improve the efficacy of other anti-cancer drugs and moreover, the ease of HDAC inhibitors cap group modification prompt many medicinal chemists to innovate and develop new generation of HDAC hybrid inhibitors. Notably, and during this short period, there are four HDAC inhibitor hybrids have entered different phases of clinical trials for treatment of different types of blood and solid tumors, namely; CUDC-101, CUDC-907, Tinostamustine, and Domatinostat. This review shed light on the most recent hybrids of HDACIs with one or more other cancer target pharmacophore. The designed multitarget hybrids include topoisomerase inhibitors, kinase inhibitors, nitric oxide releasers, antiandrogens, FLT3 and JAC-2 inhibitors, PDE5-inhibitors, NAMPT-inhibitors, Protease inhibitors, BRD4-inhibitors and other targets. This review may help researchers in development and discovery of new horizons in cancer treatment.

Immunological approaches to HIV cure

Combination antiretroviral therapy (ART) to treat human immunodeficiency virus (HIV) infection has proven remarkably successful - for those who can access and afford it - yet HIV infection persists indefinitely in a reservoir of cells, despite effective ART and despite host antiviral immune responses. An HIV cure is therefore the next aspirational goal and challenge, though approaches differ in their objectives - with 'functional cures' aiming for durable viral control in the absence of ART, and 'sterilizing cures' aiming for the more difficult to realize objective of complete viral eradication. Mechanisms of HIV persistence, including viral latency, anatomical sequestration, suboptimal immune functioning, reservoir replenishment, target cell-intrinsic immune resistance, and, potentially, target cell distraction of immune effectors, likely need to be overcome in order to achieve a cure. A small fraction of people living with HIV (PLWH) naturally control infection via immune-mediated mechanisms, however, providing both sound rationale and optimism that an immunological approach to cure is possible. Herein we review up to date knowledge and emerging evidence on: the mechanisms contributing to HIV persistence, as well as potential strategies to overcome these barriers; promising immunological approaches to achieve viral control and elimination of reservoir-harboring cells, including harnessing adaptive immune responses to HIV and engineered therapies, as well as enhancers of their functions and of complementary innate immune functioning; and combination strategies that are most likely to succeed. Ultimately, a cure must be safe, effective, durable, and, eventually, scalable in order to be widely acceptable and available.

Identification of Modulators of HIV-1 Proviral Transcription from a Library of FDA-Approved Pharmaceuticals

Human immunodeficiency virus 1 (HIV-1) is the most prevalent human retrovirus. Recent data show that 34 million people are living with HIV-1 worldwide. HIV-1 infections can lead to AIDS which still causes nearly 20,000 deaths annually in the USA alone. As this retrovirus leads to high morbidity and mortality conditions, more effective therapeutic regimens must be developed to treat these viral infections. A key target for intervention for which there are no current FDA-approved modulators is at the point of proviral transcription. One successful method for identifying novel therapeutics for treating infectious diseases is the repurposing of pharmaceuticals that are approved by the FDA for alternate indications. Major benefits of using FDA-approved drugs include the fact that the compounds have well established toxicity profiles, approved manufacturing processes, and immediate commercial availability to the patients. Here, we demonstrate that pharmaceuticals previously approved for other indications can be utilized to either activate or inhibit HIV-1 proviral transcription. Specifically, we found febuxostat, eltrombopag, and resveratrol to be activators of HIV-1 transcription, while mycophenolate was our lead inhibitor of HIV-1 transcription. Additionally, we observed that the infected cells of lymphoid and myeloid lineage responded differently to our lead transcriptional modulators. Finally, we demonstrated that the use of a multi-dose regimen allowed for enhanced activation with our transcriptional activators.

Paradigm shift of "classical" HDAC inhibitors to "hybrid" HDAC inhibitors in therapeutic interventions

'Epigenetic' regulation of genes via post-translational modulation of proteins is the current mainstay approach for the disease therapies, particularly explored in the Histone Deacetylase (HDAC) class of enzymes. Mainly sight saw in cancer chemotherapeutics, HDAC inhibitors have also found a promising role in other diseases (neurodegenerative disorders, cardiovascular diseases, and viral infections) and successfully entered in various combination therapies (pre-clinical/clinical stages). The prevalent flexibility in the structural design of HDAC inhibitors makes them easily tuneable to merge with other pharmacophore modules for generating multi-targeted single hybrids as a novel tactic to overcome drawbacks of polypharmacy. Herein, we reviewed the putative role of prevalent HDAC hybrids inhibitors in the current and prospective stage as a translational approach to overcome the limitations of the existing conventional drug candidates (parent molecule) when used either alone (drug resistance, solubility issues, adverse side effects, selectivity profile) or in combination (pharmacokinetic interactions, patient compliance) for treating various diseases.

Therapeutic potential and molecular mechanisms of mycophenolic acid as an anticancer agent

Mycophenolic acid (MPA) is the active metabolite of mycophenolate mofetil (MMF), an immunosuppressive drug approved for the prophylaxis of allograft rejection in transplant recipients. Recent advances in the role of the type II isoform of inosine-5'-monophosphate dehydrogenase (IMPDH2) in the tumorigenesis of various types of cancer have called for a second look of MPA, the first IMPDH2 inhibitor discovered a hundred years ago, to be repurposed as an anticancer agent. Over a half century, a number of in vitro and in vivo experiments have consistently shown anticancer activity of MPA against several cell lines obtained from different malignancies and murine models. However, a few clinical trials have been conducted to investigate its anticancer activity in humans, and most of which have shown unsatisfactory results. Understanding of available evidence and underlying mechanism of action is a key step to be done so as to facilitate further investigations of MPA to reach its full therapeutic potential as an anticancer agent. This article provides a comprehensive review of non-clinical and clinical evidence available to date, with the emphasis on the molecular mechanism of action in which MPA exerts its anticancer activities: induction of apoptosis, induction of cell cycle arrest, and alteration of tumor microenvironment. Future perspective for further development of MPA to be an anticancer agent is extensively discussed, with the aim of translating the anticancer property of MPA from bench to bedside.

Population pharmacokinetics of mycophenolic acid in pediatric patients with juvenile dermatomyositis and optimization of limited sampling strategy

Juvenile dermatomyositis (JDM) is a rare systemic autoimmune disease specifically affecting children. Mycophenolate mofetil (MMF) is an immunosuppressant used to treat JDM. Mycophenolic acid (MPA) is an active metabolite of MMF. This study aimed to develop a population pharmacokinetic (PPK) model of MPA in children with JDM and optimize the limited sampling strategy (LSS). Fifteen JDM patients treated with MMF, at a median age of 7.35 (range, 3.09-16.1) years, were included. Blood samples were collected at 30 minutes pre-dose, 20 minutes, 60 minutes and 180 minutes post-dose to measure the MPA concentrations. Data were retrospectively collected from the electronic medical records. A two-compartment model with first-order absorption, lag time in absorption, and first-order elimination was developed. Height and co-administered cotrimoxazole were added as the covariates to the model. Concentrations at different time points were simulated and area under the concentration-time curve (AUC_0-12 h) was calculated. By removing one sampling point at a time, AUC_0-12 h from three-point sampling strategy was re-calculated via Bayesian approach. AUC_0-12 h from the three-point sampling strategy (by removing the point at 20 minutes post-dose) had the strongest correlation with AUC_0-12 h from the four-point sampling strategy (Pearson's r = 0.971).

Safety of systemic treatments for Behçet's syndrome

INTRODUCTION

Treatment of Behçet's syndrome (BS) is aimed at controlling all symptoms of such a complex disorder, ensuring a good quality of life and preventing life-threatening complications. A better understanding of the pathogenic role of different chemokines has improved our knowledge of BS and elicited a more specific use of therapies currently available, minimizing the burden of potential side-effects related to treatment.

AREAS COVERED

This work aims to provide a detailed overview of the safety profile for current therapies available in the treatment of BS, focusing on the main side-effects, toxicity and contraindications.

EXPERT OPINION

The greatest experience in the management of BS has been achieved with the employment of monoclonal anti-tumor necrosis factor antibodies which have been advocated for BS refractory manifestations. Moreover, interleukin-1 inhibitors have proven to be effective as well as safe, despite escalation of their dosage, especially to manage the most severe and difficult-to-treat ocular manifestations. However, general treatment of BS patients remains awkward as protean clinical features may respond differently to the same treatment or even worsen. Therefore, patients' safety for therapies used in BS promotes the implementation of precision medicine, which could help targeting accurately the pathogenetic mechanisms concealed behind specific clinical phenotypes.

Use of unapproved or off-label drugs in Japan for the treatment of graft-versus-host disease and post-transplant viral infection

Many drugs are used for unapproved indications in Japan for post hematopoietic stem cell transplant (HCT) complications. To investigate unapproved or off-label drug usage for graft-versus-host disease (GVHD) and virus infections after allogeneic HCT, we analyzed the data of Japanese HCT registry. Between 2006 and 2017, 39,941 adults and children received HCT for a variety of disease and their transplant data were captured in the registry. Among them, 14,687 and 8914 patients receiving treatment for acute and/or chronic GVHD, 24,828 patients with cytomegalovirus (CMV) infection or receiving therapies for CMV, and 4943 who received treatment for other viral infections were included in the analyses of off-label or unapproved drugs. For GVHD, mycophenolate mofetil was the most frequently used off-label drug, followed by beclomethasone, infliximab, and etanercept. For viral infections other than CMV, foscarnet was the most frequently used off-label drug. Cidofovir, which is not approved for use in Japan, was mainly used for adenovirus infection. This study demonstrated that numerous off-label and unapproved drugs have been used as key drugs for GVHD and post-transplant viral infection, and the real world date in the transplant registry may serve as an important asset to regulatory purposes.

Immunosuppression Has Long-Lasting Effects on Circulating Follicular Regulatory T Cells in Kidney Transplant Recipients

Background: FoxP3⁺ follicular regulatory T cells (Tfr) have been identified as the cell population controlling T follicular helper (Tfh) cells and B cells which, are both involved in effector immune responses against transplanted tissue.

Methods: To understand the biology of Tfr cells in kidney transplant patients treated with tacrolimus and mycophenolate mofetil (MMF) combination immunosuppression, we measured circulating (c)Tfh and cTfr cells in peripheral blood by flow cytometry in n = 211 kidney transplant recipients. At the time of measurement patients were 5–7 years after transplantation. Of this cohort of patients, 23.2% (49/211) had been previously treated for rejection. Median time after anti-rejection therapy was 4.9 years (range 0.4–7 years). Age and gender matched healthy individuals served as controls.

Results: While the absolute numbers of cTfh cells were comparable between kidney transplant recipients and healthy controls, the numbers of cTfr cells were 46% lower in immunosuppressed recipients (p < 0.001). More importantly, in transplanted patients, the ratio of cTfr to cTfh was decreased (median; 0.10 vs. 0.06), indicating a disruption of the balance between cTfr and cTfh cells. This shifted balance was observed for both non-rejectors and rejectors. Previous pulse methylprednisolone or combined pulse methylprednisolone + intravenous immunoglobulin anti-rejection therapy led to a non-significant 30.6% (median) and 51.2% (median) drop in cTfr cells, respectively when compared to cTfr cell numbers in transplant patients who did not receive anti-rejection therapy. A history of alemtuzumab therapy did lead to a significant decrease in cTfr cells of 85.8% (median) compared with patients not treated with anti-rejection therapy (p < 0.0001). No association with tacrolimus or MMF pre-dose concentrations was found.

Conclusion: This cross-sectional study reveals that anti-rejection therapy with alemtuzumab significantly lowers the number of cTfr cells in kidney transplant recipients. The observed profound effects by these agents might dysregulate cTfr functions.

Mycophenolate Mofetil in C3 Glomerulopathy and Pathogenic Drivers of the Disease

BACKGROUND AND OBJECTIVES

C3 glomerulopathy is a complement-mediated disease arising from abnormalities in complement genes and/or antibodies against complement components. Previous studies showed that treatment with corticosteroids plus mycophenolate mofetil (MMF) was associated with improved outcomes, although the genetic profile of these patients was not systematically analyzed. This study aims to analyze the main determinants of disease progression and response to this therapeutic regimen.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective, multicenter, observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. Patients diagnosed with C3 glomerulopathy (n=81) or dense deposit disease (n=16) between January 1995 and March 2018 were enrolled. Multivariable and propensity score matching analyses were used to evaluate the association of clinical and genetic factors with response to treatment with corticosteroids and MMF as measured by proportion of patients with disease remission and kidney survival (status free of kidney failure).

RESULTS

The study group comprised 97 patients (84% C3 glomerulopathy, 16% dense deposit disease). Forty-two patients were treated with corticosteroids plus MMF, and this treatment was associated with a higher rate of remission and lower probability of kidney failure (79% and 14%, respectively) compared with patients treated with other immunosuppressives (24% and 59%, respectively), or ecluzimab (33% and 67%, respectively), or conservative management (18% and 65%, respectively). The therapeutic superiority of corticosteroids plus MMF was observed both in patients with complement abnormalities and with autoantibodies. However, patients with pathogenic variants in complement genes only achieved partial remission, whereas complete remissions were common among patients with autoantibody-mediated forms. The main determinant of no remission was baseline proteinuria. Relapses occurred after treatment discontinuation in 33% of the patients who had achieved remission with corticosteroids plus MMF, and a longer treatment length of MMF was associated with a lower risk of relapse.

CONCLUSIONS

The beneficial response to corticosteroids plus MMF treatment in C3 glomerulopathy appears independent of the pathogenic drivers analyzed in this study.

Therapeutic Strategies for Treatment of Immune-Mediated Hemolytic Anemia

Immune-mediated hemolytic anemia is a common hematologic disorder in dogs. Disease management involves immunosuppression using glucocorticoids, potentially in combination with other medications such as azathioprine, cyclosporine, or mycophenolate mofetil. Therapeutic drug monitoring may enhance the utility and maximize the safety of cyclosporine and mycophenolate mofetil. The disease is proinflammatory and prothrombotic. Antithrombotic drug administration is therefore essential, and anticoagulant therapy should be initiated at the time of diagnosis. Additional therapies include red blood cell transfusion to support blood oxygen content. Future therapies may include therapeutic plasma exchange, anti-CD20 monoclonal antibodies, and complement inhibitors.

Recent advances in antiviral drug development towards dengue virus

Despite the high disease burden of dengue virus, there is no approved antiviral treatment or broadly applicable vaccine to treat or prevent dengue virus infection. In the last decade, many antiviral compounds have been identified but only few have been further evaluated in pre-clinical or clinical trials. This review will give an overview of the direct-acting and host-directed antivirals identified to date. Furthermore, important parameters for further development that is, drug properties including efficacy, specificity and stability, pre-clinical animal testing, and combinational drug therapy will be discussed.

The challenge of managing comorbidities: a case report of primary Sjogren's syndrome in a patient with acute intermittent porphyria

Acute intermittent porphyria (AIP) is a rare inherited metabolic disease associated with heme metabolism. Primary Sjogren's syndrome (PSS) is a common autoimmune disease. The combined presence of AIP and PSS complicates treatment. A rare case of concomitant AIP and PSS is reported in this paper. A 30-year-old woman with AIP had recurrent acute abdominal pain, nausea and vomiting, constipation, persistent chest, back, and waist pain, red urine, positivity for porphobilinogen (PBG) in urine and a pathogenic mutation of the HMBS gene. Two and a half years after she was diagnosed with AIP, she was diagnosed with PSS based on dryness of the eyes and mouth, the elevation of immunoglobulins (IgG and IgA) and positive results on an anti-SS-A antibody test, an anti-SS-B antibody test, Schirmer's test and a labial gland biopsy. A mutation in the HMBS gene was detected in the patient and her cousin, but the patient had more severe AIP and more severe symptoms (such as epilepsy and a limp), which may be related to the co-morbidity of PSS. According to her PSS activity score, the patient had an ESSDAI score of 9 and required systemic treatment. However, potential medications were limited by AIP, so mycophenolate mofetil was eventually added to delay the progression of the primary disease.

The effect of mycophenolate mofetil on platelet function

: Mycophenolate mofetil (MMF) raises platelet counts in patients with primary immune thrombocytopenia. However, studies indicate that MMF inhibits collagen-induced platelet aggregation, potentially increasing bleeding risk following MMF therapy. The study evaluates the in-vitro effect of MMF on platelet function. Blood samples (n = 6) from healthy donors were incubated with vehicle, MMF or mycophenolic acid (MPA) at clinically relevant concentrations. Platelet aggregation was measured with flow cytometry and 96-well light transmission aggregometry (LTA). Using flow cytometry, we measured the expression of platelet CD49b, CD42b, CD42a, CD61 and CD41. Platelet activation was measured as the expression of P-selectin and the active form of the GPIIb/IIIa receptor following agonist stimulation. Agonists were: ADP, thrombin receptor-activating peptide, collagen, collagen-related peptide and U46619. The Platelet Function Analyzer-200 was used to measure global platelet function. MMF and MPA did not change platelet aggregation regardless of the agonist used. An exception was a significant, but minor decrease in collagen-induced platelet aggregation in samples with MMF (6 ± 3%, P = 0.02) and MPA (8 ± 4%, P = 0.01) compared with vehicle (22 ± 11%). However, this was not observed using the lesser sensitive LTA method. Compared with vehicle, MPA led to a significantly lower relative disposition of the surface collagen-receptor GPVI (7.8 ± 1.8 versus 8.8 ± 2.1 mean fluorescence intensity, P < 0.001). In all other platelet-related tests, neither MMF nor MPA showed any effect. In conclusion, MMF and MPA only had a minor effect on collagen-induced platelet aggregation, with MPA reducing the relative disposition of surface GPVI receptors.

Advances in steroid sparing medical management of active thyroid eye disease

Thyroid eye disease (TED) is an autoimmune inflammatory disease of the orbit and the most common extrathyroidal manifestation of Graves disease. The release of pro-inflammatory cytokines is associated with inflammation of the ocular surface and lacrimal gland along with periorbital skin erythema and edema. Resultant tissue remodeling, fibrosis, and fat deposition can impart permanent physical changes to the ocular adnexa with effects on function and cosmesis. These changes occur in the active phase of disease, and it is during this time that steroids are often relied on to help alleviate symptoms. Due to the common and predictable side effects of long-term and high-dose steroid use, there has been a continuous effort to find alternative steroid-sparing medical management options for TED. This review highlights the various research studies that support the use of these medications.

Insights into pathogenesis and clinical implications in myositis-associated interstitial lung diseases

PURPOSE OF REVIEW

Interstitial lung diseases (ILDs) have been reported to be associated with myositis (including polymyositis and dermatomyositis). These myositis-associated ILDs carry significant morbidity and mortality. This review summarizes recent findings on myositis-associated ILD with a focus on pathogenesis and emerging treatment.

RECENT FINDINGS

Recent advances in genetics have revealed 22 myositis-associated genome-wide loci, which were significantly enriched in regulatory regions in immune cells. An analysis of such disease-associated loci elucidated potential drug targets (e.g., TYK2 targeted by tofacitinib). In another study, an intronic variant in WDFY4 in association with clinically amyopathic dermatomyositis (CADM) had an effect for higher expression of a truncated WDFY4 isoform. Truncated WDFY4 markedly enhanced the MDA5-mediated NF-κB activation and cell apoptosis, indicating the dysregulated WDFY4-MDA5 pathway as a novel pathogenesis of CADM. As a novel strategy, tofacitinib treatment showed a promising improvement in survival and clinical features of CADM-associated ILD.

SUMMARY

The genetic differences in the myositis-susceptible loci may explain the heterogeneous phenotypes and treatment responses in myositis-associated ILD. The understanding of pathogenesis with the genetic background as well as autoantibodies will enable the practice of personalized treatment in the management of the disease.

Risiken und Chancen von Immuntherapien in Zeiten der Coronavirus-2019-Pandemie

Immuntherapien stellen die essenzielle Grundlage der Behandlung von neuroinflammatorischen Erkrankungen dar. In Zeiten der Coronavirus-2019 (COVID-19)-Pandemie ergibt sich im klinischen Alltag jedoch zunehmend die Frage, ob eine Immuntherapie bei neurologischen Patienten aufgrund des potenziellen Infektionsrisikos eingeleitet, intensiviert, pausiert oder gar beendet werden sollte. Unsicherheit besteht v. a. deshalb, weil verschiedene nationale und internationale Fachgesellschaften diesbezüglich unterschiedliche Empfehlungen veröffentlichten. In diesem Artikel soll ein Überblick über die Wirkmechanismen von Immuntherapien und den daraus abzuleitenden Infektionsrisiken in Bezug auf COVID-19 (durch den Coronavirus verursachte Erkrankung) gegeben werden. Potenzielle Chancen und vorteilhafte Effekte einzelner Substrate in der Akuttherapie von COVID-19 werden diskutiert.

Liposomal Delivery of Mycophenolic Acid With Quercetin for Improved Breast Cancer Therapy in SD Rats

The present study explores the influence of mycophenolic acid (MPA) in combination therapy with quercetin (QC) (impeding MPA metabolic rate) delivered using the liposomal nanoparticles (LNPs). Mycophenolic acid liposome nanoparticles (MPA-LNPs) and quercetin liposome nanoparticles (QC-LNPs) were individually prepared and comprehensively characterized. The size of prepared MPA-LNPs and QC-LNPs were found to be 183 ± 13 and 157 ± 09.8, respectively. The in vitro studies revealed the higher cellular uptake and cytotoxicity of combined therapy (MPA-LNPs + QC-LNPs) compared to individual ones. Moreover pharmacokinetics studies in female SD-rat shown higher T 1 / 2 value (1.94 fold) of combined therapy compared to MPA. Furthermore, in vivo anticancer activity in combination of MPA-LNPs and QC-LNPs was also significantly higher related to other treatments groups. The combination therapy of liposomes revealed the new therapeutic approach for the treatment of breast cancer.

Evaluation of treatment with a combination of mycophenolate mofetil and prednisolone in dogs with meningoencephalomyelitis of unknown etiology: a retrospective study of 86 cases (2009-2017)

BACKGROUND

Combination therapy with glucocorticoids and adjunctive immunomodulating drugs has been generally accepted as a standard treatment regimen for meningoencephalomyelitis of unknown etiology (MUE). We hypothesized that treatment with MMF as an adjunctive agent along with glucocorticoids would be effective and well-tolerated protocol in dogs with MUE. Eighty-six dogs with MUE between May 2009 and June 2017 were included (59 females and 27 males; mean age of 5.93 years; mean body weight of 3.83 kg). The medical records of dogs with MUE treated with prednisolone and MMF were retrospectively evaluated to determine the therapeutic response, survival time, and treatment-related adverse effects.

RESULTS

A partial or complete response (CR) was recorded for 75 dogs. The overall median survival time from the initiation of treatment was 558 days. Dogs that showed CR with no relapse over the treatment period (from diagnosis to death) had significantly longer median survival times. A significantly higher mortality hazard ratio of 4.546 was recorded in dogs that failed to achieve CR. The interval between the onset of clinical signs and the clinical presentation was not significantly associated with CR, relapse rate, and survival time. Adverse effects included gastrointestinal upsets in 26 dogs (30.23%), sporadic infections in 17 dogs (19.77%), and pancreatitis in seven dogs (8.14%).

CONCLUSIONS

The results suggest that adjunctive MMF treatment for MUE is safe and comparable to other immunosuppressive protocols. The treatment should focus on the achievement of CR and preventing relapse for successful management.

Are lupus animal models useful for understanding and developing new therapies for human SLE?

Systemic lupus erythematosus is a systemic autoimmune disease driven by a complex combination of genetic, environmental, and other immunoregulatory factors. The development of targeted therapies is complicated by heterogeneous clinical manifestations, varying organ involvement, and toxicity. Despite advances in understanding the mechanisms contributing to SLE, only one biologic drug, belimumab, is FDA-approved. The identification and development of potential therapies have largely been driven by studies in lupus animal models. Therefore, direct comparison of both the therapeutic and immunological findings in human and murine SLE studies is critical and can reveal important insights into indeed how useful and relevant are murine studies in SLE drug development. Studies involving belimumab, mycophenolate mofetil, abatacept, rituximab, and anti-interferon strategies generally demonstrated analogous findings in the attenuation of SLE manifestations and modulation of select immune cell populations in human and murine SLE. While further basic and translational studies are needed to identify SLE patient subsets likely to respond to particular therapeutic modalities and in dissecting complex mechanisms, we believe that despite some inherent weaknesses SLE mouse models will continue to be integral in developing targeted SLE therapies.

Nucleotide depletion reveals the impaired ribosome biogenesis checkpoint as a barrier against DNA damage

Many oncogenes enhance nucleotide usage to increase ribosome content, DNA replication, and cell proliferation, but in parallel trigger p53 activation. Both the impaired ribosome biogenesis checkpoint (IRBC) and the DNA damage response (DDR) have been implicated in p53 activation following nucleotide depletion. However, it is difficult to reconcile the two checkpoints operating together, as the IRBC induces p21‐mediated G1 arrest, whereas the DDR requires that cells enter S phase. Gradual inhibition of inosine monophosphate dehydrogenase (IMPDH), an enzyme required for de novo GMP synthesis, reveals a hierarchical organization of these two checkpoints. We find that the IRBC is the primary nucleotide sensor, but increased IMPDH inhibition leads to p21 degradation, compromising IRBC‐mediated G1 arrest and allowing S phase entry and DDR activation. Disruption of the IRBC alone is sufficient to elicit the DDR, which is strongly enhanced by IMPDH inhibition, suggesting that the IRBC acts as a barrier against genomic instability.

Review article: opportunities to improve and expand thiopurine therapy for autoimmune hepatitis

BACKGROUND

Thiopurines in combination with glucocorticoids are used as first-line, second-line and maintenance therapies in autoimmune hepatitis and opportunities exist to improve and expand their use.

AIMS

To describe the metabolic pathways and key factors implicated in the efficacy and toxicity of the thiopurine drugs and to indicate the opportunities to improve outcomes by monitoring and manipulating metabolic pathways, individualising dosage and strengthening the response.

METHODS

English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed.

RESULTS

Thiopurine methyltransferase activity and 6-tioguanine (6-thioguanine) nucleotide levels influence drug efficacy and safety, and they can be manipulated to improve treatment response and prevent myelosuppression. Methylated thiopurine metabolites are associated with hepatotoxicity, drug intolerance and nonresponse and their production can be reduced or bypassed. Universal pre-treatment assessment of thiopurine methyltransferase activity and individualisation of dosage to manipulate metabolite thresholds could improve outcomes. Early detection of thiopurine resistance by metabolite testing, accurate estimations of drug onset and strength by surrogate markers and adjunctive use of allopurinol could improve the management of refractory disease. Dose-restricted tioguanine (thioguanine) could expand treatment options by reducing methylated metabolites, increasing the bioavailability of 6-tioguanine nucleotides and ameliorating thiopurine intolerance or resistance.

CONCLUSIONS

The efficacy and safety of thiopurines in autoimmune hepatitis can be improved by investigational efforts that establish monitoring strategies that allow individualisation of dosage and prediction of outcome, increase bioavailability of the active metabolites and demonstrate superiority to alternative agents.

Systemic safety analysis of mycophenolate in Graves' orbitopathy

PURPOSE

The dual antiproliferative mechanism of mycophenolate appears to be beneficial in Graves' orbitopathy (GO).

METHODS

Safety data from the two published mycophenolate trials and the original database of the European Group on Graves' Orbitopathy (EUGOGO) trial were systematically analyzed. Treatment efficacy stratified by individual visual parameters of activity and severity were compared.

RESULTS

A total of 129 adverse events (AE) involving 50 patients (29.4%) were noted among all mycophenolate-treated patients. Mycophenolate sodium plus intravenous glucocorticoid (MPS + GC) group of the EUGOGO trial recorded significantly more AE (55.4% versus 4.6% of patients affected) and serious adverse events (SAE) (12.5% versus 0%) than mycophenolate mofetil (MMF) group of the Chinese trial. None of those SAE was side effect (SE). Most SE in MPS + GC group were mild. Gastrointestinal disorders, infection and liver dysfunction affected 8.8%, 7.1% and 1.2% of all mycophenolate-treated patients (versus 5.4%, 5.4% and 1.2% of all patients on GC monotherapy, respectively). MPS + GC did not significantly increase the risk of infection or liver dysfunction when compared to GC monotherapy. No cytopenia, serious infection or treatment-related mortality was reported. The much higher AE rates of mycophenolate trials in other autoimmune diseases or transplantations suggested that major mycophenolate toxicities were mostly dose- and duration dependent. Mycophenolate, either as monotherapy or as combination, achieved better overall response than GC monotherapy.

CONCLUSION

The risk-benefit ratio of low-dose mycophenolate treatment in active moderate-to-severe GO is highly favorable given its reassuring safety profile with low rate of mild-to-moderate SE and promising efficacy.

Merits and culprits of immunotherapies for neurological diseases in times of COVID-19

Immunosuppression and immunomodulation are valuable therapeutic approaches for managing neuroimmunological diseases. In times of the Coronavirus disease 2019 (COVID-19) pandemic, clinicians must deal with the question of whether immunotherapy should currently be initiated or discontinued in neurological patients. Uncertainty exists especially because different national medical associations publish different recommendations on the extent to which immunotherapies must be continued, monitored, or possibly switched during the current pandemic. Based on the most recently available data both about the novel coronavirus and the approved immunotherapies for neurological diseases, we provide an updated overview that includes current treatment strategies and the associated COVID-19 risk, but also the potential of immunotherapies to treat COVID-19.

Dermatomyositis: An Update on Diagnosis and Treatment

Dermatomyositis is a rare inflammatory disease with characteristic cutaneous findings and varying amounts of systemic involvement. Patients may present with skin disease alone, have concomitant muscle disease, or have extracutaneous manifestations such as pulmonary disease or an associated malignancy. Given such diverse presentations, dermatomyositis is both a diagnostic and therapeutic challenge. However, a prompt diagnosis is of utmost importance to institute adequate therapy and screen patients for an associated malignancy. Dermatologists should play a crucial role in the diagnosis and management of patients with dermatomyositis as cutaneous disease tends to be chronic, negatively impact quality of life, and be more recalcitrant to therapy. In this review, we discuss diagnosis, with a focus on myositis-specific antibodies and their associated phenotypes. We also review therapies available for this often refractory skin disease.

Low-dose corticosteroid and mycophenolate for primary treatment of minimal change disease

BACKGROUND

Mycophenolate has been shown to be effective in glomerular disease. However, the role of mycophenolate in the first-line treatment of adult-onset idiopathic minimal change disease (MCD) has not been systematically studied in a randomized fashion.

AIM

To evaluate the therapeutic efficacy of enteric-coated mycophenolate sodium combined with low-dose corticosteroid as first-line treatment for MCNS.

DESIGN

A prospective, open-label, randomized clinical trial.

METHODS

Twenty adult patients with biopsy proven MCD were recruited and randomly assigned to receive either enteric-coated Mycophenolate Sodium (EC-MPS) plus low-dose prednisolone (Group 1: Prednisolone 0.25 mg/kg/day, n = 10) or standard-dose prednisolone (Group 2: Prednisolone 1 mg/kg/day, n = 10).

RESULTS

After 24 weeks of therapy, eight patients in Group 1 vs. seven of patients in Group 2 achieved complete remission (P = 0.606). Both groups showed a significant reduction of urine protein excretion (P < 0.05) and increased serum albumin (P < 0.001) vs. baseline levels. However, no significant between-group differences were demonstrated. The relapse rate was also similar in both groups. Both treatment regimens were well tolerated but there were more patient reported adverse effects in the standard-dose prednisolone group.

CONCLUSION

EC-MPS plus low-dose prednisolone is non-inferior to standard-dose prednisolone therapy in inducing clinical remission and preventing relapse in adult-onset idiopathic MCD and is associated with better tolerability and less adverse effects. This trial is registered with the ClinicalTrials.gov number NCT01185197.

Requirements for Proper Immunosuppressive Regimens to Limit Translational Failure of Cardiac Cell Therapy in Preclinical Large Animal Models

Various cell-based therapies are currently investigated in an attempt to tackle the high morbidity and mortality associated with heart failure. The need for these therapies to move towards the clinic is pressing. Therefore, preclinical large animal studies that use non-autologous cells are needed to evaluate their potential. However, non-autologous cells are highly immunogenic and trigger immune rejection responses resulting in potential loss of efficacy. To overcome this issue, adequate immunosuppressive regimens are of imminent importance but clear guidelines are currently lacking. In this review, we assess the immunological barriers regarding non-autologous cell transplantation and immune modulation with immunosuppressive drugs. In addition, we provide recommendations with respect to immunosuppressive regimens in preclinical cardiac cell-replacement studies.

Glucocorticoids negatively regulates chaperone mediated autophagy and microautophagy

Glucocorticoids are released from the adrenal cortex and are important for regulating various physiological functions. However, a persistent increase in glucocorticoids due to chronic stress causes various dysfunctions in the central nervous system which can lead to mental disorders such as depression. Macroautophagy, one of the pathways of the autophagy-lysosome protein degradation system, is dysregulated in psychiatric disorders, implicating a disturbance of protein degradation in the pathogenesis of psychiatric disorders. In the present study, we investigated whether glucocorticoids affect the activity of chaperone-mediated autophagy (CMA) and microautophagy (mA), the other two pathways of the autophagy-lysosome system. Treatment of human-derived AD293 cells and primary cultured rat cortical neurons with dexamethasone, a potent glucocorticoid receptor agonist, and endogenous glucocorticoids decreased both CMA and mA activities. However, this decrease was significantly suppressed by treatment with RU-486, a glucocorticoid receptor antagonist. In addition, dexamethasone significantly decreased lysosomal Hsc70. These findings suggest that glucocorticoids negatively regulate CMA and mA in a glucocorticoid receptor-dependent manner, and provide evidence for CMA and mA as novel therapeutic targets for depression.

Pfeifer-Weber-Christian Disease: A Case Report and Review of Literature on Visceral Involvements and Treatment Choices

Pfeifer-Weber-Christian disease (PWCD) is a rare idiopathic disease characterized by lobular panniculitis of adipose tissue with systemic symptoms and multiple organ involvement. Even though the systemic involvement is rare, it is life-threatening and represent a treatment challenge for the clinicians. We report a case of PWCD characterized by hepatic, hematologic, and renal involvement, with good response to mofetil mycophenolate and prednisone treatment. A 47-year-old female presented several months’ history of painful subcutaneous nodules, fever and lymphadenopathy with recent appearing of microcytic hypochromic anemia, leucopenia with neutropenia, and increase in transaminase. Skin biopsy showed lobular panniculitis with lymph-histiocytic and neutrophilic infiltrates with necrosis of adipocytes. A combination therapy of corticosteroid with mofetil mycophenolate was effective. Moreover, we discuss the clinical manifestation and the therapeutic choices in PWCD, from classical immunosuppressive drugs to new biotechnological agents, and we provide a comprehensive review of the available literature.

Medical treatment in thyroid eye disease in 2020

Thyroid eye disease (TED) affects 25% of patients with Graves' hyperthyroidism, where 1 in 20 patients has active, moderate-to-severe disease that will require medical treatment for reducing TED activity and severity. Intravenous corticosteroid has been the mainstay of treatment for active moderate-to-severe TED. With improved understanding of the pathophysiology of TED, immunotherapy targeting different molecular pathways including T cells, B cells, cytokines and cell surface receptors have been investigated in randomised clinical trials. This review provides an overview of the current advances in medical treatment including teprotumumab, tocilizumab, rituximab and mycophenolate and the indications for their use in the management of active, moderate-to-severe TED.

A Toolbox of Potential Immune-Related Therapies for Inflammatory Cardiomyopathy

Myocarditis is a multifactorial disorder, characterized by an inflammatory reaction in the myocardium, predominantly triggered by infectious agents, but also by antigen mimicry or autoimmunity in susceptible individuals. Unless spontaneously resolved, a chronic inflammatory course concludes with cardiac muscle dysfunction portrayed by ventricular dilatation, clinically termed inflammatory cardiomyopathy (Infl-CM). Treatment strategies aim to resolve chronic inflammation and preserve cardiac function. Beside standard heart failure treatments, which only play a supportive role in this condition, systemic immunosuppressants are used to diminish inflammatory cell function at the cost of noxious side effects. To date, the treatment protocols are expert-based without large clinical evidence. This review describes concept and contemporary strategies to alleviate myocardial inflammation and sheds light on potential inflammatory targets in an evidence-based order.

Interindividual Variability in Lymphocyte Stimulation and Transcriptomic Response Predicts Mycophenolic Acid Sensitivity in Healthy Volunteers

Mycophenolic acid (MPA) is an immunosuppressant commonly used to prevent renal transplant rejection and treat glomerulonephritis. MPA inhibits IMPDH2 within stimulated lymphocytes, reducing guanosine synthesis. Despite the widespread use of MPA, interindividual variability in response remains with rates of allograft rejection up to 15% and approximately half of individuals fail to achieve complete remission to lupus nephritis. We sought to identify contributors to interindividual variability in MPA response, hypothesizing that the HPRT1 salvage guanosine synthesis contributes to variability. MPA sensitivity was measured in 40 healthy individuals using an ex vivo lymphocyte viability assay. Measurement of candidate gene expression (n ± 40) and single‐cell RNA‐sequencing (n ± 6) in lymphocytes was performed at baseline, poststimulation, and post‐MPA treatment. After stimulation, HPRT1 expression was 2.1‐fold higher in resistant individuals compared with sensitive individuals (P ± 0.049). Knockdown of HPRT1 increased MPA sensitivity (12%; P ± 0.003), consistent with higher expression levels in resistant individuals. Sensitive individuals had higher IMPDH2 expression and 132% greater stimulation. In lymphocyte subpopulations, differentially expressed genes between sensitive and resistant individuals included KLF2 and LTB. Knockdown of KLF2 and LTB aligned with the predicted direction of effect on proliferation. In sensitive individuals, more frequent receptor‐ligand interactions were observed after stimulation (P ± 0.0004), but fewer interactions remained after MPA treatment (P ± 0.0014). These data identify a polygenic transcriptomic signature in lymphocyte subpopulations predictive of MPA response. The degree of lymphocyte stimulation, HPRT1, KLF2, and LTB expression may serve as markers of MPA efficacy.

History of organ transplantation and the development of key immunosuppressants

The history of organ transplantation is limited to the last century. To overcome the barrier of the host immune system, which results in transplant rejection, the pioneers of transplantation achieved their first success by performing a kidney transplantation between identical twins. This achievement led the transplant clinicians to perform transplantations with immunological barriers present. Strategies such as whole-body irradiation combined with steroids yielded success in kidney transplantation between non-identical twins and siblings. However, owing to the toxicity related to irradiation, the paradigm shifted to the use of immunosuppressants. Azathioprine, steroids, and anti-lymphocyte globulin became the first multiple immunosuppressive regimens. With the introduction of cyclosporine, the 1-year survival rate increased by more than 80%. Cyclosporine, azathioprine, and steroids became the new standard maintenance regimens until the introduction of tacrolimus and mycophenolate mofetil, which replaced cyclosporine and azathioprine, respectively. The most recent change in immunosuppressants was the development of monoclonal antibodies with specific binding sites, such as CD20 (rituximab) and CD25 (basiliximab). With the innovation of molecular engineering and new insights into the costimulatory pathways, new molecules are under investigation in the field of transplantation.

Exploiting immunometabolism and T cell function for solid organ transplantation

Cellular metabolism is central to T cell function and proliferation, with most of the research to date focusing on cancer and autoimmunity. Cellular metabolism is associated with a host of physiological phenomena, from epigenetic changes, to cellular function and fate. For the purpose of this review, we will discuss the metabolism of T cells relating to their differentiation and function. We will cover a variety of metabolic processes, ranging from glycolysis to amino acid metabolism. Understanding how T cell metabolism informs T cell function may be useful to understand alloimmune responses and design novel therapies to improve graft outcome.

Initial serum creatinine concentration affects clinical outcomes in patients with IgA nephropathy treated with mycophenolate mofetil combined with low-dose prednisone

Indicators for predicting the efficacy of mycophenolate mofetil (MMF) have so far remained elusive. The present study aimed to identify predictive indicators of the efficacy of MMF combined with low-dose prednisone in patients with IgA nephropathy. A total of 598 patients presenting with primary IgA nephropathy at our center were screened. Patients were followed up for 18 months, where the end-point was defined as complete clinical remission. Cox proportional hazards models were performed for analyzing the initial serum creatinine (SCr) concentration to predict incomplete clinical remission. In total, 7 of 71 patients (9.86%) were in complete clinical remission at the final visit. Logistic regression indicated that the hazard ratio (HR) for quartile 4 was significantly higher than the HR for quartile 1 (quartile 4 vs. quartile 1: HR, 2.51; 95% CI, 1.20-5.21; P=0.01). Additional adjustment for the confounding variables, including age, sex, systolic BP, diastolic BP, proteinuria, uric acid, serum triglyceride, hemoglobin, serum albumin, serum total cholesterol and The Oxford classification of the models, did not reduce the HRs for the association between the initial SCr concentration and risk of incomplete clinical remission (quartile 4 vs. quartile 1: HR, 7.27; 95% CI, 1.21-43.63; P=0.03). Each unit increase in the initial SCr concentration was associated with a 67 and 194% increase in the risk of incomplete clinical remission based on model 1 (95% CI, 1.02-2.73; P=0.04) and model 2 (95% CI, 1.01-8.60; P=0.048), respectively. In conclusion, in the present cohort of patients with IgA nephropathy treated with MMF plus low-dose prednisone, the initial SCr concentration was an independent risk factor for incomplete clinical remission.

Phase II, multi-center, open-label, single-arm clinical trial evaluating the efficacy and safety of Mycophenolate Mofetil in patients with high-grade locally advanced or metastatic osteosarcoma (ESMMO): rationale and design of the ESMMO trial

BACKGROUND

Clinical outcomes of patients with osteosarcoma remain unsatisfactory, with little improvement in a 5-year overall survival over the past three decades. There is a substantial need for further research and development to identify and develop more efficacious agents/regimens in order to improve clinical outcomes of patients for whom the prognosis is unfavorable. Recently, mycophenolate mofetil, a prodrug of mycophenolic acid, has been found to have anticancer activity against osteosarcoma in both in vitro and animal experiments, so that further investigation in humans is warranted.

METHODS

A total of 27 patients with high-grade locally advanced or metastatic osteosarcoma will be enrolled into this phase II, multi-center, open-label, single-arm, two-stage clinical trial. The main objectives of this study are to determine the efficacy and safety of mycophenolate mofetil in the patients. The primary endpoint is progression-free survival at 16 weeks; the secondary endpoints include progression-free survival, overall survival, overall response rate, safety parameters, pharmacokinetic parameters, biomarkers, pain score, and quality of life. Mycophenolate mofetil at the initial dose of 5 g/day or lower will be administered for 4 cycles (28 days/cycle) or until disease progression or unacceptable toxicity. The dose of mycophenolate mofetil may be reduced by 1-2 g/day or withheld for some Grade 3 or Grade 4 toxicities whenever clinically needed. The duration of study participation is approximately 4-5 months, with a minimum of 12 study visits. If mycophenolate mofetil proves beneficial to some patients, as evidenced by stable disease or partial response at 16 weeks, administration of mycophenolate mofetil will continue in the extension period.

DISCUSSION

This trial is the first step in the translation of therapeutic potential of mycophenolate mofetil emerging from in vitro and animal studies into the clinical domain. It is designed to assess the efficacy and safety of mycophenolate mofetil in patients with high-grade locally advanced or metastatic osteosarcoma. The results will provide important information about whether or not mycophenolate mofetil is worth further development.

TRIAL REGISTRATION

This trial was prospectively registered on Thai Clinical Trials Registry (registration number: TCTR20190701001). The posted information will be updated as needed to reflect protocol amendments and study progress.

The role of complement activation in autoimmune liver disease

INTRODUCTION

The complement system, an essential part of the innate immune system, is involved in various autoimmune diseases. Activation of the complement system by autoantibodies results in immune activation and tissue damage. At the moment little is known about the role of the complement system in autoimmune liver disease, including primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH). Since inhibition of the complement system is currently being tested in several autoimmune diseases as a therapeutic option, its role in autoimmune liver disease requires further clarification.

METHODS

A review of the literature was performed on studies investigating complement activation in PBC, PSC and AIH. Since data on AIH were lacking immunohistochemical staining for IgG, C1q, C3d, C4d and C5b9 was performed on liver tissue of nine AIH patients, two healthy controls and one positive control (acute liver failure caused by paracetamol intoxication).

RESULTS

Immunohistochemical analysis in AIH revealed increased production of C3 and C4 by hepatocytes. Despite a strong staining for IgG in the immune infiltrate in AIH, C3d, C4d and C5b9 deposition was only present in one AIH patient and the deposition was restricted to the interface between portal tracts and liver parenchyma. No deposition was found in all other AIH patients or healthy controls. Literature review showed raised plasma C3 and C4 levels in AIH, PBC and PSC patients compared to healthy controls. For PBC and PSC no complement depositions at the bile ducts were reported.

CONCLUSION AND DISCUSSION

Although complement is involved in various autoimmune diseases, the role of complement in autoimmune liver disease seems limited. Therefore it is unlikely that complement inhibition will become a novel treatment option for these diseases.

Comparative modeling and structure based drug repurposing of PAX2 transcription factor for targeting acquired chemoresistance in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a pancreatic malignancy suffering from poor prognosis; the worst among all types of cancer. Chemotherapy, which is the standard regime for treatment in most cases, is often rendered useless as drug resistance quickly sets in after prolonged exposure to the drug. The implication of PAX2 transcription factor in regulating several ATP-binding cassette (ABC) transporter proteins that are responsible for the acquisition of drug resistance in PDAC makes it a potential target for treatment purposes. In this study, the 3D structure of PAX2 protein was modeled, and the response of key amino acids to perturbation was identified. Subsequently, kappadione, a vitamin K derivative, was found to bind efficiently to PAX2 with a binding energy of -9.819 kcal/mol. The efficacy of mechanism and mode of binding was studied by docking the protein with DNA in the presence and absence of the drug. The presence of kappadione disrupted DNA binding with key effector resides, preventing the DNA from coming into contact with the binding region essential for protein translation. By occupying the DNA binding region and replacing it with a ligand, the mechanism by which DNA interacts with PAX2 could be manipulated. Inhibition of PAX2-DNA binding using kappadione and other small molecules can prove to be beneficial for combating chemoresistance in PDAC, as proposed through in silico approaches.Communicated by Ramaswamy H. Sarma.

The role of immunosuppressive agents in the management of severe and refractory immune-related adverse events

The advent of immune checkpoint inhibitors has improved survival in some types of cancer and brought promising prospects to cancer immunotherapy. Despite their clinical benefits, significant off-target toxicities resulting from the immune system activation have been observed, namely immune-related adverse events (irAEs), which pose to clinicians a new challenge of optimal management. With steroids being the mainstay of current management of irAEs, immunosuppressive agents are especially indicated for severe or steroid-refractory cases, based on current immunopathophysiological knowledge and on extrapolations of treatment options for primary autoimmune disorders. This review focuses on the status and recent clinical progress of immunosuppressive agents in the management of severe and steroid-refractory irAEs.

A Defect in Thymic Tolerance Causes T Cell-Mediated Autoimmunity in a Murine Model of COPA Syndrome

COPA syndrome is a recently described Mendelian autoimmune disorder caused by missense mutations in the coatomer protein complex subunit α (COPA) gene. Patients with COPA syndrome develop arthritis and lung disease that presents as pulmonary hemorrhage or interstitial lung disease (ILD). Immunosuppressive medications can stabilize the disease, but many patients develop progressive pulmonary fibrosis, which requires life-saving measures, such as lung transplantation. Because very little is understood about the pathogenesis of COPA syndrome, it has been difficult to devise effective treatments for patients. To date, it remains unknown which cell types are critical for mediating the disease as well as the mechanisms that lead to autoimmunity. To explore these issues, we generated a Copa^E241K/+ germline knock-in mouse bearing one of the same Copa missense mutations in patients. Mutant mice spontaneously developed ILD that mirrors lung pathology in patients, as well as elevations of activated cytokine-secreting T cells. In this study, we show that mutant Copa in epithelial cells of the thymus impairs the thymic selection of T cells and results in both an increase in autoreactive T cells and decrease in regulatory T cells in peripheral tissues. We demonstrate that T cells from Copa^E241K/+ mice are pathogenic and cause ILD through adoptive transfer experiments. In conclusion, to our knowledge, we establish a new mouse model of COPA syndrome to identify a previously unknown function for Copa in thymocyte selection and demonstrate that a defect in central tolerance is a putative mechanism by which COPA mutations lead to autoimmunity in patients.

Stim1 Polymorphism Disrupts Immune Signaling and Creates Renal Injury in Hypertension

Background

Spontaneously hypertensive rats of the stroke‐prone line (SHR‐A3) develop hypertensive renal disease as a result of naturally occurring genetic variation. Our prior work identified a single‐nucleotide polymorphism unique to SHR‐A3 that results in truncation of the carboxy terminus of STIM1. The SHR‐B2 line, which is also hypertensive but resists hypertensive renal injury, expresses the wild‐type STIM1. STIM1 plays a central role in lymphocyte calcium signaling that directs immune effector responses. Here we show that major defects in lymphocyte function affecting calcium signaling, nuclear factor of activated T cells activation, cytokine production, proliferation, apoptosis, and regulatory T‐cell development are present in SHR‐A3 and attributable to STIM1.

Methods and Results

To assess the role of Stim1 variation in susceptibility to hypertensive renal injury, we created a Stim1 congenic line, SHR‐A3(Stim1‐B2), and STIM1 function was rescued in SHR‐A3. We found that Stim1 gene rescue restores disturbed lymphocyte function in SHR‐A3. Hypertensive renal injury was compared in SHR‐A3 and the SHR‐A3(Stim1‐B2) congenic line. Histologically assessed renal injury was markedly reduced in SHR‐A3(Stim1‐B2), as were renal injury biomarker levels measured in urine. Stim1 deficiency has been linked to the emergence of antibody‐mediated autoimmunity. Renal glomerular immunoglobulin deposition was greater in SHR‐A3 than SHR‐B2 and was reduced by Stim1 congenic substitution. Serum anti–double‐stranded DNA antibody titers in SHR‐A3 were elevated compared with SHR‐B2 and were reduced in SHR‐A3(Stim1‐B2).

Conclusions

Stim1 deficiency in lymphocyte function originating from Stim1 truncation in SHR‐A3 combines with hypertension to create end organ disease and may do so as a result of antibody formation.

Cardiac allograft vasculopathy: Insights on pathogenesis and therapy

Cardiac allograft vasculopathy (CAV) is a unique accelerated form of coronary vascular disease affecting heart transplant recipients. This complication is a significant contributor to medium- to long-term post-transplant morbidity and mortality. There is a high prevalence of CAV with approximately one in three patients developing CAV by 5 years post-transplant. Morphologically, CAV is characterized by concentric coronary intimal hyperplasia in both the epicardial arteries and intramural microvasculature. Although several immune and non-immune factors have been identified, their precise pathogenic mechanisms, interactions, and relative importance in the development of CAV are not well defined. The advent of improved imaging surveillance modalities has resulted in earlier detection during the disease process. However, overall management of CAV remains challenging due to paucity of treatment. This review aims to discuss key concepts on the pathogenesis of CAV and current management strategies, focusing on the use of mammalian target of rapamycin inhibitors.

Current and Emerging Drug Therapies for Connective Tissue Disease-Interstitial Lung Disease (CTD-ILD)

Interstitial lung disease (ILD) can be associated with all connective tissue diseases and is an important cause of morbidity and mortality. The management of connective tissue disease-interstitial lung disease (CTD-ILD) is challenging due substantial heterogeneity in disease behaviour and paucity of controlled clinical trials to guide treating clinicians. Not all patients require treatment, and the decision to treat needs to be individualised based on a patient's observed disease behaviour, baseline and longitudinal lung function measurements, extent of lung involvement on radiology and patient factors including age, co-morbidities and personal preference. If indicated, treatment of the CTD-ILD is largely with immunomodulation, with the aim to prevent progression of the ILD before further irreversible lung injury and disability occurs. Corticosteroids, cyclophosphamide, mycophenolate mofetil and azathioprine are the most common immunosuppressive agents currently used to treat CTD-ILD, demonstrating stability of lung function in case series and a small number of randomised controlled trials in ILD associated with systemic sclerosis. Biological and non-biological disease-modifying anti-rheumatic drugs, and the anti-fibrotics nintedanib and pirfenidone, have revolutionised the treatment of connective tissue diseases and idiopathic ILD, respectively. Furthermore, anti-fibrotics have recently demonstrated safety and efficacy in ILD associated with systemic sclerosis. There remains a critical unmet need to clarify when and in whom to initiate treatment, and which agent(s) to utilise to achieve optimal outcomes for CTD-ILD patients whilst minimising harms through prospective multicentre trials. This review highlights the challenges faced when treating patients with CTD-ILD and summarises available evidence for current, emerging and novel therapies.

Cryo-EM structures demonstrate human IMPDH2 filament assembly tunes allosteric regulation

Inosine monophosphate dehydrogenase (IMPDH) mediates the first committed step in guanine nucleotide biosynthesis and plays important roles in cellular proliferation and the immune response. IMPDH reversibly polymerizes in cells and tissues in response to changes in metabolic demand. Self-assembly of metabolic enzymes is increasingly recognized as a general mechanism for regulating activity, typically by stabilizing specific conformations of an enzyme, but the regulatory role of IMPDH filaments has remained unclear. Here, we report a series of human IMPDH2 cryo-EM structures in both active and inactive conformations. The structures define the mechanism of filament assembly, and reveal how filament-dependent allosteric regulation of IMPDH2 makes the enzyme less sensitive to feedback inhibition, explaining why assembly occurs under physiological conditions that require expansion of guanine nucleotide pools. Tuning sensitivity to an allosteric inhibitor distinguishes IMPDH from other metabolic filaments, and highlights the diversity of regulatory outcomes that can emerge from self-assembly.

Mycophenolate-induced Colitis: A Case Report with Focused Review of Literature

Mycophenolate mofetil (MMF) is an immunosuppressive medication used for the management of various autoimmune diseases, and patients with bone marrow and solid organ transplants. Gastrointestinal side effects are seen 45% of the time and they include nausea (29%), vomiting (23%), constipation (38%), diarrhea (50%-92%), and colitis (9%). In 98% of cases, resolution of diarrhea occurs within 20 days upon discontinuation of the MMF. Data is scarce regarding approach in the treatment of MMF-induced colitis. We report a case of MMF-induced colitis diagnosed by colonoscopy and histopathology. This case illustrates the challenges encountered while managing MMF-induced colitis.

Different Routes of Proton Pumps Inhibitors Co-Administration have Significant Impact on Mycophenolate Acid (MPA) Serum Levels in Heart Transplant Recipients

Background

Antiproliferative drugs including mycophenolate mofetil (MMF) are widely accepted part of an immunosuppressive therapy following heart transplantation. Proton pump inhibitors (PPIs) are routinely administered after cardiac surgery procedures including transplantation. They may also have impact on mycophenolate acid (MPA) serum levels.

Material/Methods

There were 30 consecutive patients (28 male and 2 female patients) with a mean age of 45±12 years who were enrolled into this study. MPA serum levels were studied; PPIs were intravenously and orally administered.

Results

The mean MPA plasma concentrations were statistically significantly different between parenteral group (2.3±1.4 umg/mL) and oral group (3.1±2.2 umg/mL) (P=0.036) before immunosuppressive drug administration (C-0 time). There was a statistically significant different drug concentration at the second sample time C-30 (30 minutes after drug intake) reaching 4.4±2.8 umg/mL versus 7.9±4.5 umg/mL (P<0.05). There was no statistically significant difference in MPA plasma concentration at the 3^rd measurement C-120 (10.7±4,9 umg/mL versus 9.8±5 umg/mL) (P=0.3). There is a statistically significant different MMF serum concentration after oral intake and intravenous infusion at C-30 (2.4±1.4 in group 1 versus 3.3±2.5 in group 2, P<0.036) but not at C-120 time interval (8.9±5.0 versus 9.8±5.3 in group 1 and 2, respectively) (P=0.3).

Conclusions

Our study was the first study that compared different routes of PPI co-administration on MPA serum levels in a transplant recipient group. Our study revealed that the parenteral route of administration only slowed not decreased MPA pharmacokinetics within 120 minutes following MMF administration.

Ocular side effects of antirheumatic medications: a qualitative review

Topic

This paper reviews the ocular side effects of medications used in the treatment of rheumatological conditions.

Clinical relevance

Rheumatic diseases are inflammatory conditions that may affect the skin, blood vessels, joints, muscles and internal organs. Immunosuppressive agents are often used as treatment and while powerful, they carry side effects and toxicities that need careful monitoring. Ophthalmic complications have been reported with the use of antirheumatic medications; however, there is a lack of literature synthesising these reports. This paper addresses this gap and hopes to inform both rheumatologists and ophthalmologists as they work together on the management of patients with rheumatological conditions.

Methods

PubMed literature search was conducted from November to September 2019 searching for ocular side effects with the use of 25 rheumatological drugs.

Results

A total of 111 papers were included in this review. Adverse side effects were divided into non-infectious and infectious causes. Traditional disease-modifying antirheumatic drugs (DMARDs) were associated with pruritus, irritation and dryness of the conjunctiva while biologic DMARDS showed reports of new-onset/recurrent uveitis and demyelinating conditions. Infectious side effects included episodes of cytomegalovirus retinitis, toxoplasmic chorioretinitis and endophthalmitis. Other serious side effects were encountered and included in this review.

Conclusion

The goal of this paper is to inform healthcare providers about potential ocular side effects from rheumatological medications. Healthcare providers are encouraged to learn more about these ophthalmic complications and find relevance within their clinical practice.

Purine Nucleotides in the Regulation of Brown Adipose Tissue Activity

Non-shivering thermogenesis in mammalian brown adipose tissue is a powerful mechanism to defend normothermia in cold climates. To minimize the loss of chemical energy, the central functional component, mitochondrial uncoupling protein 1, UCP1, must be tightly regulated. The canonical pathway of UCP1 activation includes lipolytic release of free fatty acids in response to an adrenergic signal. Activating fatty acids overcome constitutive inhibition of UCP1 by the di- and triphosphate forms of purine nucleotides, i.e., ATP, ADP, GTP, and GDP. Cellular concentrations of inhibitory, free nucleotides are subject to significant, adrenergically induced alterations. The regulatory components involved may constitute novel drug targets to manipulate brown fat thermogenesis and thereby organismic energy balance. We here review evidence for and against a dominant role of nucleotides in thermogenic control, describe conceptual routes to endogenously and pharmacologically alter free nucleotide pool size, speculate on a signaling role of degradation products released from active brown fat, and highlight gaps in our understanding of signaling and metabolic pathways involved.