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MBio Jun 2024The purine nucleotides ATP and GTP are made from the common precursor inosine monophosphate (IMP). Maintaining the correct balance of these nucleotides for optimal cell...
UNLABELLED
The purine nucleotides ATP and GTP are made from the common precursor inosine monophosphate (IMP). Maintaining the correct balance of these nucleotides for optimal cell growth is controlled in part by the enzyme IMP dehydrogenase (IMPDH), which catalyzes the first dedicated step of GTP biosynthesis. The regulation of IMPDH mRNA and protein levels in the yeast grown in liquid culture has been studied in some detail, but regulation of IMPDH protein under conditions of cellular crowding on a solid substrate has not been examined. Here, we report real-time, live-cell analysis of the accumulation of the Imd2 isoform of IMPDH in yeast cells forming a monolayer colony in a microfluidic device over a 50-hour time course. We observe two distinct phases of increased Imd2 accumulation: a guanine-insensitive phase early in outgrowth and a guanine-sensitive phase later, when cells become crowded. We show that the IMPDH inhibitor mycophenolic acid enhances both phases of increase. Deletion of a transcription attenuator upstream of the mRNA start site that decreases Imd2 mRNA synthesis in the presence of high GTP increases the baseline level of Imd2 protein 10-fold and abolishes guanine-sensitive but not guanine-insensitive induction. Our results suggest that at least two mechanisms of yeast Imd2 regulation exist, the known GTP-dependent attenuation of RNA polymerase II elongation and a GTP concentration-independent pathway that may be controlled by cell growth state. Live-cell analysis of IMPDH protein levels in a growing yeast colony confirms a known mechanism of regulation and provides evidence for an additional mode of regulation.
IMPORTANCE
This study used live-cell microscopy to track changes in the level of a key enzyme in GTP nucleotide biosynthesis, inosine monophosphate dehydrogenase (IMPDH), during growth of a brewers yeast colony over 2 days in a microfluidic device. The results show that feedback regulation via transcription attenuation allows cells to adapt to nutrient limitation in the crowded environs of a yeast colony. They also identify a novel mode of regulation of IMPDH level that is not driven by guanine nucleotide availability.
PubMed: 38940616
DOI: 10.1128/mbio.01021-24 -
Journal of Hematology & Oncology Jun 2024Relapse remains a challenge after transplantation in pediatric patients with hematological malignancies. Myeloablative regimens used for disease control are associated...
BACKGROUND
Relapse remains a challenge after transplantation in pediatric patients with hematological malignancies. Myeloablative regimens used for disease control are associated with acute and long-term adverse effects. We used a CD45RA-depleted haploidentical graft for adoptive transfer of memory T cells combined with NK-cell addback and hypothesized that maximizing the graft-versus-leukemia (GVL) effect might allow for reduction in intensity of conditioning regimen.
METHODS
In this phase II clinical trial (NCT01807611), 72 patients with hematological malignancies (complete remission (CR)1: 25, ≥ CR2: 28, refractory disease: 19) received haploidentical CD34 + enriched and CD45RA-depleted hematopoietic progenitor cell grafts followed by NK-cell infusion. Conditioning included fludarabine, thiotepa, melphalan, cyclophosphamide, total lymphoid irradiation, and graft-versus-host disease (GVHD) prophylaxis consisted of a short-course sirolimus or mycophenolate mofetil without serotherapy.
RESULTS
The 3-year overall survival (OS) and event-free-survival (EFS) for patients in CR1 were 92% (95% CI:72-98) and 88% (95% CI: 67-96); ≥ CR2 were 81% (95% CI: 61-92) and 68% (95% CI: 47-82) and refractory disease were 32% (95% CI: 11-54) and 20% (95% CI: 6-40). The 3-year EFS for all patients in morphological CR was 77% (95% CI: 64-87) with no difference amongst recipients with or without minimal residual disease (P = 0.2992). Immune reconstitution was rapid, with mean CD3 and CD4 T-cell counts of 410/μL and 140/μL at day + 30. Cumulative incidence of acute GVHD and chronic GVHD was 36% and 26% but most patients with acute GVHD recovered rapidly with therapy. Lower rates of grade III-IV acute GVHD were observed with NK-cell alloreactive donors (P = 0.004), and higher rates of moderate/severe chronic GVHD occurred with maternal donors (P = 0.035).
CONCLUSION
The combination of a CD45RA-depleted graft and NK-cell addback led to robust immune reconstitution maximizing the GVL effect and allowed for use of a submyeloablative, TBI-free conditioning regimen that was associated with excellent EFS resulting in promising long-term outcomes in this high-risk population. The trial is registered at ClinicalTrials.gov (NCT01807611).
Topics: Humans; Female; Male; Killer Cells, Natural; Child; Adolescent; Transplantation, Haploidentical; Child, Preschool; Hematopoietic Stem Cell Transplantation; Transplantation Conditioning; Memory T Cells; Hematologic Neoplasms; Graft vs Host Disease; Infant; Young Adult; Adult; Treatment Outcome; Graft vs Leukemia Effect
PubMed: 38937803
DOI: 10.1186/s13045-024-01567-0 -
La Revue de Medecine Interne Jun 2024Behcet disease (BD) is a systemic vasculitis which can involve many different organ systems. Neurological involvement (NBD) occurs in 5.3% to 59% of BD patients. The... (Review)
Review
Behcet disease (BD) is a systemic vasculitis which can involve many different organ systems. Neurological involvement (NBD) occurs in 5.3% to 59% of BD patients. The diagnosis is challenging especially in case of inaugural neurological presentation, and is based on a constellation of clinical, laboratory, and neuroimaging findings. NBD can be subdivided into parenchymal NBD through an immune mediated meningoencephalitis with a predilection to the brainstem, basal ganglia, thalamus, cranial nerves, and spinal cord involvement, and extraparenchymal NBD encompassing cerebral veinous thrombosis and intracranial arterial involvement. Brain magnetic resonance shows ill-defined areas of oedema with high signal intensity on T2-FLAIR images, isointense or hypointense in T1-weighted images in the basal ganglia area or in the brainstem, which may extend to the diencephalic structures. Swelling might be noticed. Hemorrhages can be seen, such as contrast enhancement (blood brain barrier disruption). Magnetic resonance venography and computerized tomographic angiography can be used to diagnose extraparenchymal NBD. Treatment of parenchymatous forms is based on glucocorticoids associated with oral immunosuppressants (azathioprine, mycophenolate mofetil or methotrexate) in mild forms, and intravenous cyclophosphamide or infliximab in severe forms. The management of cerebral thrombosis consists of steroids course associated with an oral anticoagulation. An early recognition of this condition is mandatory to initiate adequate therapies in order to improve outcomes and limit the risk of sequelae, relapses, or death. The aim of this review is to summarize a comprehensive review on the various neurological presentations of BD with emphasizes on diagnostic tools, prognosis, and therapeutic issues.
PubMed: 38937151
DOI: 10.1016/j.revmed.2024.06.007 -
Chemistry (Weinheim An Der Bergstrasse,... Jun 2024In several biological processes, H2S is known to function as an endogenous gaseous agent. It is very necessary to monitor H2S and relevant physiological processes in...
In several biological processes, H2S is known to function as an endogenous gaseous agent. It is very necessary to monitor H2S and relevant physiological processes in vivo. Herein, a new type of fluorophore with a reliable leaving group allows for excited-state intramolecular transfer characteristics (ESIPT), inspired by mycophenolic acid. A morpholine ring was connected at the maleimide position to target the lysosome. Subsequently, the dinitrophenyl group known for a photoinduced electron transfer (PET) effect, was connected to allow for an effective "turn-on" probe Lyso-H2S. Lyso-H2S demonstrated strong selectivity towards H2S, large Stokes shift (111 nm), and an incredibly low detection limit (41.8 nM). The imaging of endogenous and exogenous H2S in living cells (A549 cell line) was successfully achieved because of the specificity and ultra-low toxicity (100 % cell viability at 50 µM concentration of Lyso-H2S.) Additionally, Lyso-H2S was also employed to visualize the activity of H2S in the gallbladder and intestine in a living zebrafish model. This is the first report of a fluorescent probe to track H2S sensing in specific organ systems to our knowledge.
PubMed: 38934891
DOI: 10.1002/chem.202401733 -
International Journal of Molecular... Jun 2024C3 glomerulopathy is a rare disease, characterized by an abnormal activation of the complement's alternative pathway that leads to the accumulation of the C3 component... (Review)
Review
C3 glomerulopathy is a rare disease, characterized by an abnormal activation of the complement's alternative pathway that leads to the accumulation of the C3 component in the kidney. The disease recurs in more than half of kidney transplant recipients, with a significant impact on graft survival. Recurrence of the primary disease represents the second cause of graft loss after organ rejection. In C3 glomerulopathy, there are several risk factors which can promote a recurrence during transplantation, such as delayed graft function, infection and monoclonal gammopathy. All these events can trigger the alternative complement pathway. In this review, we summarize the impact of C3 glomerulopathy on kidney grafts and present the latest treatment options. The most widely used treatments for the disease include corticosteroids and mycophenolate mofetil, which are already used chronically by kidney transplant recipients; thus, additional treatments for C3 glomerulopathy are required. Currently, several studies using anti-complement drugs (i.e., eculizumab, Ravalizumab, avacopan) for C3 glomerulopathy in kidney transplant patients are ongoing with encouraging results.
Topics: Humans; Kidney Transplantation; Complement C3; Graft Rejection; Glomerulonephritis; Mycophenolic Acid
PubMed: 38928213
DOI: 10.3390/ijms25126508 -
International Journal of Molecular... Jun 2024Allogeneic hematopoietic stem cell transplantation has become a treatment option for otherwise non-curative conditions, both malignant and benign, affecting children and... (Review)
Review
Allogeneic hematopoietic stem cell transplantation has become a treatment option for otherwise non-curative conditions, both malignant and benign, affecting children and adults. Nevertheless, the latest research has been focusing extensively on transplantation from related and unrelated haploidentical donors, suitable for patients requiring emergent hematopoietic stem cell transplantation (HSCT) in the absence of an HLA-matched donor. Haploidentical HSCT (haplo-HSCT) can be an effective treatment for non-malignant pediatric disorders, such as primary immunodeficiencies or hemoglobinopathies, by enabling a much quicker selection of the appropriate donor for virtually all patients, low incidence of graft-versus-host disease (GVHD), and transplant-related mortality (TRM). Moreover, the outcomes of haplo-HSCT among children with hematological malignancies have improved radically. The most demanding tasks for clinicians are minimizing T-cell-mediated alloreactivity as well as early GVHD prevention. As a result, several T-cell depletion approaches, such as ex vivo T-cell depletion (TCD), and T-cell replete approaches, such as a combination of anti-thymocyte globulin (ATG), post-transplantation cyclophosphamide (PTCy), cyclosporine/tacrolimus, mycophenolate mofetil, or methotrexate, have been taken up. As more research is needed to establish the most beneficial form of therapy, haplo-HSCT is currently considered an alternative donor strategy for pediatric and adult patients with complications like viral and bacterial infections, invasive fungal disease, and GVHD.
Topics: Humans; Hematopoietic Stem Cell Transplantation; Child; Graft vs Host Disease; Transplantation, Haploidentical; Hematologic Diseases; Transplantation Conditioning
PubMed: 38928087
DOI: 10.3390/ijms25126380 -
Clinical and Translational Science Jun 2024The recommended immunosuppressive treatment after kidney transplantation consists of tacrolimus, mycophenolate mofetil, and low-dose corticosteroids. Drug concentrations...
Immune responsiveness in stable kidney transplantation patients: Complete inhibition of T-cell proliferation but residual T-cell activity during maintenance immunosuppressive treatment.
The recommended immunosuppressive treatment after kidney transplantation consists of tacrolimus, mycophenolate mofetil, and low-dose corticosteroids. Drug concentrations are monitored using therapeutic drug monitoring (TDM), which does not necessarily correlate with pharmacodynamic activity. To find the balance between optimal efficacy and minimal toxicity, it might be more informative to monitor patients' immunological status rather than drug concentrations. We selected a panel of T-cell-based immune assays, which were used for immunomonitoring of 14 stable kidney transplantation patients. Whole blood was incubated with a T-cell stimulus, after which T-cell proliferation, T-cell activation marker expression and cytokine production were measured to study residual immune activity in vitro (before drug intake; drug added to the incubation) and ex vivo (after drug intake). T-cell proliferation was completely suppressed in all patients over the full day, while IL-2, IFN-γ, CD71, and CD154 showed fluctuations over the day with a strong inhibition (75%-25%) at 2 h post-dose. The level of inhibition was variable between patients and could not be related to pharmacokinetic parameters or the presence of regulatory or senescence immune cells. Moreover, the level of inhibition did not correlate with the in vitro tacrolimus drug effect as studied by incubating pre-dose blood samples with additional tacrolimus. Overall, IL-2, IFN-γ, CD71, and CD154 seem to be good markers to monitor residual immune activity of transplantation patients. To evaluate the correlation between these pharmacodynamic biomarkers and clinical outcome, prospective observational studies are needed.
Topics: Humans; Kidney Transplantation; Male; Immunosuppressive Agents; Middle Aged; Female; T-Lymphocytes; Cell Proliferation; Adult; Tacrolimus; Lymphocyte Activation; Drug Monitoring; Aged; Mycophenolic Acid; Interferon-gamma
PubMed: 38923308
DOI: 10.1111/cts.13860 -
Zeitschrift Fur Gastroenterologie Jun 2024As of now, there exists no established therapy for ELP. Retinoids, which are standard in treating cutaneous LP, do not exhibit positive effects in ELP. While topical...
As of now, there exists no established therapy for ELP. Retinoids, which are standard in treating cutaneous LP, do not exhibit positive effects in ELP. While topical glucocorticosteroids often yield favorable responses in esophageal inflammation, some cases prove recalcitrant or refractory. In such instances, various immunosuppressive therapies have been attempted with variable success.This report details a severe case of ELP that showed resistance to prednisolone, acitretin, alitretinoin, adalimumab, tacrolimus, hydroxychloroquine plus mycophenolate mofetil, and cyclophosphamide. The initiation of the JAK inhibitor tofacitinib induced an impressive clinical, endoscopic, and histological remission. This positive response to a JAK inhibitor is discussed in the context of our evolving understanding of the immune-mediated pathogenesis of this disease.
PubMed: 38917831
DOI: 10.1055/a-2300-0375 -
Pharmacological Reports : PR Jun 2024
Correction: Liquid chromatography-tandem mass spectrometry method for mycophenolic acid and its glucuronide determination in saliva samples from children with nephrotic syndrome.
PubMed: 38916851
DOI: 10.1007/s43440-024-00617-1 -
Microbiology Spectrum Jun 2024Mycophenolate mofetil (MMF) is commonly utilized for the treatment of neuromyelitis optica spectrum disorders (NMOSD). However, a subset of patients experience...
Mechanisms of gastrointestinal toxicity in neuromyelitis optica spectrum disorder patients treated with mycophenolate mofetil: insights from a mouse model and human study.
UNLABELLED
Mycophenolate mofetil (MMF) is commonly utilized for the treatment of neuromyelitis optica spectrum disorders (NMOSD). However, a subset of patients experience significant gastrointestinal (GI) adverse effects following MMF administration. The present study aims to elucidate the underlying mechanisms of MMF-induced GI toxicity in NMOSD. Utilizing a vancomycin-treated mouse model, we compiled a comprehensive data set to investigate the microbiome and metabolome in the GI tract to elucidate the mechanisms of MMF GI toxicity. Furthermore, we enrolled 17 female NMOSD patients receiving MMF, who were stratified into non-diarrhea NMOSD and diarrhea NMOSD (DNM) groups, in addition to 12 healthy controls. The gut microbiota of stool samples was analyzed using 16S rRNA gene sequencing. Vancomycin administration prevented weight loss and tissue injury caused by MMF, affecting colon metabolomes and microbiomes. Bacterial β-glucuronidase from Bacteroidetes and Firmicutes was linked to intestinal tissue damage. The DNM group showed higher alpha diversity and increased levels of Firmicutes and Proteobacteria. The β-glucuronidase produced by Firmicutes may be important in causing gastrointestinal side effects from MMF in NMOSD treatment, providing useful information for future research on MMF.
IMPORTANCE
Neuromyelitis optica spectrum disorder (NMOSD) patients frequently endure severe consequences like paralysis and blindness. Mycophenolate mofetil (MMF) effectively addresses these issues, but its usage is hindered by gastrointestinal (GI) complications. Through uncovering the intricate interplay among MMF, gut microbiota, and metabolic pathways, this study identifies specific gut bacteria responsible for metabolizing MMF into a potentially harmful form, thus contributing to GI side effects. These findings not only deepen our comprehension of MMF toxicity but also propose potential strategies, such as inhibiting these bacteria, to mitigate these adverse effects. This insight holds broader implications for minimizing complications in NMOSD patients undergoing MMF therapy.
PubMed: 38916339
DOI: 10.1128/spectrum.04307-23