sirolimus and Virus-Diseases

Balanced nutrition and appropriate dietary interventions are fundamental in the prevention and management of viral infections. Additionally, accurate modulation of the inflammatory response is necessary to achieve an adequate antiviral immune response. Many studies, both in vitro with mammalian cells and in vivo with small animal models, have highlighted the antiviral properties of resveratrol, rapamycin and metformin. The current review outlines the mechanisms of action of these three important compounds on the cellular pathways involved with viral replication and the mechanisms of virus-related diseases, as well as the current status of their clinical use.

Topics: Animals; Antiviral Agents; Host-Pathogen Interactions; Humans; Metformin; Resveratrol; Signal Transduction; Sirolimus; Virus Diseases; Virus Replication

Viruses are the leading cause of infections after solid organ transplant. The antiviral properties of mammalian target of rapamycin inhibitors (mTORis) have been ascribed to a variety of mechanisms and historical data have supported their use over other immunosuppressants for a myriad of viruses. Herein, we summarize the most current data to highlight the role of mTORis in the management of viral infections after solid organ transplant. The mTORis play a clear role in the management of cytomegalovirus, and have data supporting their potential use for BK virus and human herpesvirus 8-related Kaposi sarcoma. No data definitively supports mTORis for use in Epstein-Barr virus-mediated posttransplant lymphoproliferative disorder or hepatitis C virus viral replication. Although theoretically an advantageous therapy for hepatitis C virus-related liver allograft fibrosis and human immunodeficiency virus, mTORi use specifically for these indications is less attractive with modern treatments currently available. Data surrounding mTORi efficacy in preventing rejection, and their toxicity profile must be balanced with their potential antiviral effects in combination with patient-specific factors.

Topics: Everolimus; Humans; Organ Transplantation; Postoperative Complications; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Virus Diseases

Macrophage is a key cell of immune system, it participates in antiviral, antimicrobial and antitumor defense of the organism, also in regeneration and reparation of tissues. Macrophage coordinates functioning of immune system, participates in tumor growth progression. The process of inflammation consists of two stages. Cytotoxical potential of immunocompetent cells will be realized in the first stage, to avoid a bacterial infection. The second stage of inflammatory process is associated with reparation and regeneration. During inflammation, according it stages, macrophages change functional state, switching from cytotoxical M1 to M2, that associated with reparation. We suppose, that rapamysin, a suppressor of mTOR, causes completely different effects on tumor associated macrophages and cells of microglia. Rapamycin transforms tissue macrophages into M1 phenotype, promoting the tumor regression. While in microglial cells of the central nervous system it induces transformation into M2 phenotype, facilitating the course of the neurodegenerative disease and slowing down the aging.

Topics: Animals; Bacterial Infections; Humans; Macrophages; Neoplasms; Neurodegenerative Diseases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Virus Diseases

The mammalian target of rapamycin (mTOR) is an intracellular kinase that regulates cell growth and metabolism. Its specific inhibitor rapamycin is currently used in transplant recipients as an immunosuppressive drug to prevent allograft rejection. Studies have shown complex and diverse mechanisms for the immunosuppressive effects of rapamycin. The drug has been reported to inhibit T-cell proliferation, induce anergy, modulate T-cell trafficking, promote regulatory T cells, and also prevent maturation of dendritic cells as well as production of type I interferon. However, several other studies have paradoxically demonstrated immunostimulatory effects of rapamycin by improving antigen presentation and regulating cytokine production from macrophages and myeloid dendritic cells. Recently, it has been shown that rapamycin also exhibits immunostimulatory effects on memory CD8(+) T-cell differentiation. The drug improved both quantity and quality of memory CD8(+) T cells induced by viral infection and vaccination, showing that mTOR is a major regulator of memory CD8(+) T-cell differentiation. These discoveries have implications for the development of novel vaccine regimens. Here, we review the role of mTOR in memory CD8(+) T-cell differentiation and compare the effect of rapamycin among CD8(+) T cells, CD4(+) T cells, and dendritic cells. Also, we discuss potential application of these findings in a clinical setting.

Topics: Animals; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Differentiation; Dendritic Cells; Humans; Immunologic Factors; Immunologic Memory; Intracellular Signaling Peptides and Proteins; Organ Transplantation; Protein Serine-Threonine Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Vaccines; Virus Diseases

Autophagy is one of the intracellular systems that is responsible for protein trafficking (degradation/recycling) in eukaryotic cells. This ubiquitous process contributes to cytosolic homeostasis, but its deregulation is often associated with various pathologies, including neurodegenerative diseases and cancer and pathologies with an altered inflammatory response. This review provides an overview of autophagy and discusses its regulation, function and future therapeutic possibilities, with a focus on the role of autophagy in inflammation.

Topics: Animals; Apoptosis; Autophagy; Bacterial Infections; Homeostasis; Humans; Inflammation; Lysosomes; Proteasome Endopeptidase Complex; Protein Kinase Inhibitors; Proteins; Sirolimus; Stress, Physiological; Virus Diseases

Topics: Animals; Anti-Infective Agents; Antiviral Agents; B-Lymphocytes; Bacterial Infections; Cyclosporine; HIV; Humans; Immunosuppressive Agents; Parasitic Diseases; Polyenes; Sirolimus; T-Lymphocytes; Tacrolimus; Virus Diseases

Rapamycin and its derivatives are specific inhibitors of mammalian target of rapamycin (mTOR) kinase and, as a result, are well-established immunosuppressants and antitumorigenic agents. Additionally, this class of drug promotes gene delivery by facilitating lentiviral vector entry into cells, revealing its potential to improve gene therapy efforts. However, the precise mechanism was unknown. Here, we report that mTOR inhibitor treatment results in down-regulation of the IFN-induced transmembrane (IFITM) proteins. IFITM proteins, especially IFITM3, are potent inhibitors of virus-cell fusion and are broadly active against a range of pathogenic viruses. We found that the effect of rapamycin treatment on lentiviral transduction is diminished upon IFITM silencing or knockout in primary and transformed cells, and the extent of transduction enhancement depends on basal expression of IFITM proteins, with a major contribution from IFITM3. The effect of rapamycin treatment on IFITM3 manifests at the level of protein, but not mRNA, and is selective, as many other endosome-associated transmembrane proteins are unaffected. Rapamycin-mediated degradation of IFITM3 requires endosomal trafficking, ubiquitination, endosomal sorting complex required for transport (ESCRT) machinery, and lysosomal acidification. Since IFITM proteins exhibit broad antiviral activity, we show that mTOR inhibition also promotes infection by another IFITM-sensitive virus, Influenza A virus, but not infection by Sendai virus, which is IFITM-resistant. Our results identify the molecular basis by which mTOR inhibitors enhance virus entry into cells and reveal a previously unrecognized immunosuppressive feature of these clinically important drugs. In addition, this study uncovers a functional convergence between the mTOR pathway and IFITM proteins at endolysosomal membranes.

Topics: Antiviral Agents; Cell Line; Cell Line, Tumor; Endosomes; HEK293 Cells; HeLa Cells; Host-Pathogen Interactions; Humans; Membrane Proteins; Protein Transport; RNA-Binding Proteins; Sirolimus; TOR Serine-Threonine Kinases; Virus Diseases; Virus Internalization

mTOR has important roles in regulation of both innate and adaptive immunity, but whether and how mTOR modulates humoral immune responses have yet to be fully understood. To address this issue, we examined the effects of rapamycin, a specific inhibitor of mTOR, on B cell and CD4 T cell responses during acute infection with lymphocytic choriomeningitis virus. Rapamycin treatment resulted in suppression of virus-specific B cell responses by inhibiting proliferation of germinal center (GC) B cells. In contrast, the number of memory CD4 T cells was increased in rapamycin-treated mice. However, the drug treatment caused a striking bias of CD4 T cell differentiation into Th1 cells and substantially impaired formation of follicular helper T (Tfh) cells, which are essential for humoral immunity. Further experiments in which mTOR signaling was modulated by RNA interference (RNAi) revealed that B cells were the primary target cells of rapamycin for the impaired humoral immunity and that reduced Tfh formation in rapamycin-treated mice was due to lower GC B cell responses that are essential for Tfh generation. Additionally, we found that rapamycin had minimal effects on B cell responses activated by lipopolysaccharide (LPS), which stimulates B cells in an antigen-independent manner, suggesting that rapamycin specifically inhibits B cell responses induced by B cell receptor stimulation with antigen. Together, these findings demonstrate that mTOR signals play an essential role in antigen-specific humoral immune responses by differentially regulating B cell and CD4 T cell responses during acute viral infection and that rapamycin treatment alters the interplay of immune cell subsets involved in antiviral humoral immunity.. mTOR is a serine/threonine kinase involved in a variety of cellular activities. Although its specific inhibitor, rapamycin, is currently used as an immunosuppressive drug in transplant patients, it has been reported that rapamycin can also stimulate pathogen-specific cellular immunity in certain circumstances. However, whether and how mTOR regulates humoral immunity are not well understood. Here we found that rapamycin treatment predominantly inhibited GC B cell responses during viral infection and that this led to biased helper CD4 T cell differentiation as well as impaired antibody responses. These findings suggest that inhibition of B cell responses by rapamycin may play an important role in regulation of allograft-specific antibody responses to prevent organ rejection in transplant recipients. Our results also show that consideration of antibody responses is required in cases where rapamycin is used to stimulate vaccine-induced immunity.

Topics: Animals; Apoptosis; B-Lymphocyte Subsets; Cell Line; Cell Survival; Germinal Center; Hematopoietic Stem Cell Transplantation; Hematopoietic Stem Cells; Host-Pathogen Interactions; Immunity, Humoral; Immunization; Immunologic Memory; Immunomodulation; Mice; Mice, Transgenic; Signal Transduction; Sirolimus; T-Lymphocyte Subsets; T-Lymphocytes, Helper-Inducer; TOR Serine-Threonine Kinases; Transduction, Genetic; Virus Diseases

At present, 150 clinical trials are registered with the National Cancer Institute, which investigate the efficacy of inhibitors of the PI3K/Akt/mTOR pathway against multiple cancers. Efficacy varies not so much with drug action, but with tumor type, as different cancer types (and different pre-clinical models) exhibit widely differing susceptibilities to mTOR inhibitors, such as rapamycin. Viral cancers appear to be among the most mTOR-addicted and most rapamycin-sensitive cancers. We discuss the different mTOR inhibitors that are currently available and in clinical trials. We also speculate how the molecular makeup of viral cancers could guide the selection and use of known and novel mTOR inhibitors to treat virus-associated malignancies.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Virus Diseases

Autoimmune cytopaenia is a rare, but severe complication after solid organ transplantation. We retrospectively analysed 57 paediatric intestinal transplants performed in 49 patients between 1999 and 2009. Autoimmune cytopaenia was observed in six patients; it appeared after an average of 10 months post-transplant. Warm autoimmune haemolytic anaemia was developed in three patients, cold autoimmune haemolytic anaemia in one and two presented a mixed type. Incidence and causes for haematological cytopaenia such as the following were investigated: immunosuppression, major blood mismatch, viral infection, malignancy, passenger lymphocyte syndrome and lymphoproliferative disorders. Initial treatment included high-dose steroids, intravenous immunoglobulin, plasmapheresis and maintenance of body temperature above 37°C in those with cold autoantibodies. Inclusion of the spleen in multivisceral transplants seems to be an important risk factor. All patients, except one, relapsed after classic therapy, requiring additional treatments. Sirolimus conversion was performed in four patients. One died after infection. The immunosuppressive therapies associated with other concomitant factors, such as viral infections, lymphoproliferative disorders, graft-versus-host disease, passenger lymphocyte syndrome and the inclusion of the spleen as part of multivisceral graft seem to play an important part in the development of autoimmune processes after intestinal transplantation. Therapy is not well established, especially in those resistant to first-line treatment.

Topics: Alemtuzumab; Anemia, Hemolytic, Autoimmune; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Neoplasm; Child; Female; Graft Rejection; Humans; Immunosuppression Therapy; Intestines; Lymphoproliferative Disorders; Male; Retrospective Studies; Sirolimus; Spleen; Transplantation, Homologous; Virus Diseases

The authors present a 10-year-old girl with tuberous sclerosis complex who has been receiving rapamycin for 10 months for seizure control. She was started at 0.05 mg/kg/d and titrated to an effective dose of 0.15 mg/kg/d. There was a dramatic reduction in seizure frequency with rapamycin therapy. Further studies are needed to objectively investigate the benefits of rapamycin in tuberous sclerosis complex and to clarify its mechanism of seizure control.

Topics: Anticonvulsants; Carbamazepine; Cerebral Cortex; Child; Dose-Response Relationship, Drug; Drug Therapy, Combination; Female; Fructose; Humans; Immunosuppressive Agents; Magnetic Resonance Imaging; Neurosurgical Procedures; Paresis; Seizures; Sirolimus; Topiramate; Treatment Outcome; Tuberous Sclerosis; Virus Diseases

IPEX (immune dysregulation, polyendocrinopathy, enteropathy, and X-linked syndrome), a rare inflammatory disease caused by mutations of Foxp3, destroys the immunoregulatory environment of affected male infants. Data on optimal therapy are limited.. We reviewed the effect of sirolimus use in our cohort of IPEX and IPEX-like patients (n = 7).. Our patients exhibited features of enteropathy and recurrent infections with bacterial and viral pathogens. Before initiating sirolimus, six patients were treated with corticosteroids. Several also received other immunosuppressive agents. After starting sirolimus, six patients had improvement in diarrhea, and two were able to decrease corticosteroid dosages. Several also had significantly decreased number of infections after treatment. Of the three patients with post-treatment duodenal biopsies, two showed improvement in villous architecture. No significant adverse events occurred. Our experience suggests that sirolimus is a clinically effective and safe therapeutic option in IPEX and IPEX-like patients.

Topics: Cohort Studies; Diarrhea; Dose-Response Relationship, Drug; Duodenitis; Duodenum; Female; Forkhead Transcription Factors; Humans; Immunocompromised Host; Infant; Infant, Newborn; Infections; Male; Mutation; Polyendocrinopathies, Autoimmune; Sirolimus; Virus Diseases