Detailed short-term follow-up high-resolution CT series of differentiation syndrome

A 57-year-old man with acute promyelocytic leukaemia (APML) received induction therapy including all-trans-retinoic acid (ATRA). At day 15, he developed dyspnoea, haemoptysis and hypoxia. Thorax CT demonstrated diffuse ground-glass opacity and consolidation predominantly in dorsal regions, which may reflect increased vascular permeability. He was diagnosed with differentiation syndrome. After dexamethasone was administered and chemotherapy suspended, his symptoms improved and abnormal lesions mostly disappeared on follow-up CT examinations. We report a short-term high-resolution CT series of differentiation syndrome.

Role of cardiolipins, mitochondria, and autophagy in the differentiation process activated by all-trans retinoic acid in acute promyelocytic leukemia

The role played by lipids in the process of granulocytic differentiation activated by all-trans retinoic acid (ATRA) in Acute-Promyelocytic-Leukemia (APL) blasts is unknown. The process of granulocytic differentiation activated by ATRA in APL blasts is recapitulated in the NB4 cell-line, which is characterized by expression of the pathogenic PML-RARα fusion protein. In the present study, we used the NB4 model to define the effects exerted by ATRA on lipid homeostasis. Using a high-throughput lipidomic approach, we demonstrate that exposure of the APL-derived NB4 cell-line to ATRA causes an early reduction in the amounts of cardiolipins, a major lipid component of the mitochondrial membranes. The decrease in the levels of cardiolipins results in a concomitant inhibition of mitochondrial activity. These ATRA-dependent effects are causally involved in the granulocytic maturation process. In fact, the ATRA-induced decrease of cardiolipins and the concomitant dysfunction of mitochondria precede the differentiation of retinoid-sensitive NB4 cells and the two phenomena are not observed in the retinoid-resistant NB4.306 counterparts. In addition, ethanolamine induced rescue of the mitochondrial dysfunction activated by cardiolipin deficiency inhibits ATRA-dependent granulocytic differentiation and induction of the associated autophagic process. The RNA-seq studies performed in parental NB4 cells and a NB4-derived cell population, characterized by silencing of the autophagy mediator, ATG5, provide insights into the mechanisms underlying the differentiating action of ATRA. The results indicate that ATRA causes a significant down-regulation of CRLS1 (Cardiolipin-synthase-1) and LPCAT1 (Lysophosphatidylcholine-Acyltransferase-1) mRNAs which code for two enzymes catalyzing the last steps of cardiolipin synthesis. ATRA-dependent down-regulation of CRLS1 and LPCAT1 mRNAs is functionally relevant, as it is accompanied by a significant decrease in the amounts of the corresponding proteins. Furthermore, the decrease in CRLS1 and LPCAT1 levels requires activation of the autophagic process, as down-regulation of the two proteins is blocked in ATG5-silenced NB4-shATG5 cells.

Investigation on the Binding and Conformational Change of All-trans-Retinoic Acid with Peptidyl Prolyl cis/trans Isomerase Pin1 Using Spectroscopic and Computational Techniques

Binding and conformational change of all-trans-retinoic acid (ATRA) with peptidyl prolyl cis/trans isomerase Pin1 were investigated systematically by spectroscopic and computational techniques under experimentally optimized physiological conditions. The intrinsic fluorescence of Pin1 was quenched through a static quenching mechanism in the presence of ATRA with binding constants on the order of 105 mol/L. Thermodynamic parameters (ΔH = 15.76 kJ/mol and ΔS = 158.36 J/mol·K at 293 K) and computational results illustrated that the hydrophobic interactions played a significant role in the binding process of ATRA to Pin1, but electrostatic forces, weak van der Waals, and hydrogen bonds cannot be ignored. Circular dichroism, fluorescence spectra, and computational simulations revealed that ATRA interacted with residues Lys63 and Arg69 of Pin1 to affect its conformational changes. Molecular dynamic simulation, principal component analysis, and free energy landscape monitored the dynamical conformational characteristics of ATRA binding to Pin1. All in all, the present research might provide a reference for the development and design of retinoic acid drugs that inhibit the activity of Pin1.

All-Trans Retinoic Acid Modulates The Immune Status of M2 Macrophages in Experimental Periodontitis Induced by Porphyromonas Gingivalis in Mice

Background: M2 macrophages are important innate immune cells that participate in the pathogenesis of periodontitis. The effect of all-trans retinoic acid (ATRA) on the immune status of M2 macrophages in periodontitis has not been reported.Methods: An experimental model of periodontitis was established in mice by oral administration of Porphyromonas gingivalis, and then ATRA or vehicle was administered orally to model mice every other day (P.g+ATRA and P.g+CMC mice, respectively). Flow cytometry was used to analyze the numbers of F4/80+CD206+ M2 macrophages in the gingiva, spleen, and peritoneal lavage fluid (PLF). M2 macrophage–related cytokines were quantified by real-time reverse transcription-polymerase chain reaction.Results: Compared with P.g+CMC mice, P.g+ATRA mice showed a significantly reduced cemento-enamel junction to alveolar bone crest (CEJ-ABC) distance. The percentage of F4/80+CD206+ M2 macrophages in gingiva, PLF and spleen in model mice increased after ATRA treatment. The mRNA expression levels of M2 macrophage­–related cytokines (IL-10, TGF-b1 and Arg-1) in gingiva, PLF and spleen of P.g+ATRA mice were higher than those of P.g+CMC mice.Conclusions: These results suggested that ATRA modulates the immune status of M2 macrophages and provides protection against periodontitis by enhancing M2 activation.

Could the candidate causal gene (LZTFL1) identified by Oxford University scientists, which doubles the risk of COVID-19-related respiratory failure, be used to boost the Weak immunogenicity of COVID-19 mRNA vaccines in patients with B-cell chronic lymphocytic leukemia (CLL)???. A double edged sword

Patients with B-cell chronic lymphocytic leukemia (CLL) have an increased risk of severe infections due to disease- and treatment-related immunodeficiency. As a result, patients with hematologic malignancies have been given priority for primary COVID-19 vaccination. Unfortunately, many studies have suggested that patients with B-cell chronic lymphocytic leukemia (CLL) who have been fully vaccinated can develop severe and often fatal complications. Therefore, adjuvants that can induce mRNA vaccine efficacy are desperately needed for this category of patients with haematological malignancies. A recent, study by Oxford University scientists showed that leucine zipper transcription factor-like 1(LZTFL1), as a candidate causal gene and its enhancer the rs17713054 A risk allele was significantly responsible for the twofold increased risk of respiratory failure from COVID-19 associated with 3p21.31.By using sequence analysis, the risk allele generates a second CCAAT/enhancer binding protein beta (CEBPB) motif in the enhancer. Moreover, neither LZTFL1 variants found in T cells nor B cells are responsible for increasing death risk from COVID-19 infection according to oxford study. Here, we propose attestable hypothesis that trans retinoic acid could enhance the immune response in vaccinated patients with B-cell chronic lymphocytic leukemia (CLL) according to the recent findings of Oxford scientists by inducing the casual gene(LZTFL1) in CD4 T cells and inhibiting (CEBPB) motif.Conclusions Haematological malignancies (blood cancers) patients are more vulnerable to COVID-19 disuse severity and mortality. Un fortunately mRNA vaccine seem to be less effective with weak immune response and insufficient level of generated antibodies in this category of patients. Therefore we suggest all trans retinoic acid is a good candidate as mRNA COVID-19 vaccine adjuvant via inducing LZTFL1 gene in CD4Tcells and this activation could improve the immune response and increase the level of the generated antibodies. Moreover LZTFL1 gene in CD4 T cells is not associated with increasing risk of COVID-19 infection because of absence of its enhancer(The risk allele of the SNP, rs17713054 A) in immune cells according to oxford recent study. In addition to all trans retinoic acid could inhibit CCAAT/enhancer binding protein beta motif that is generated by The risk allele of the SNP, rs17713054 A

Do High-mobility Group Box 1 Gene Polymorphisms Affect the Incidence of Differentiation Syndrome in Acute Promyelocytic Leukemia?

Differentiation syndrome (DS) is an inflammatory complication seen in some patients with acute promyelocytic leukemia (APL) undergoing differentiation therapy with all-trans retinoic acid (ATRA) and/or arsenic trioxide (ATO). It is unknown how DS occurs, but it is believed that it is caused by inflammatory cytokines release from differentiating leukemic cells. High mobility group box-1 (HMGB1) is a DNA-binding protein that acts as a cytokine outside of cells and may play a role in inflammation. This study was conducted to determine whether HMGB1 polymorphisms (rs1360485, rs2249825 and rs1060348) are associated with the incidence of differentiation syndrome in acute promyelocytic leukemia patients treated with all-trans retinoic acid and arsenic trioxide. One hundred and thirty APL patients and 100 healthy controls were included. Seventeen patients with differentiation syndrome were selected according to the PETHEMA criteria. Tetra-primer ARMS polymerase chain reaction (tetra-ARMS PCR) was used to determine the genotype distribution of polymorphisms. DNA sequencing was done to validate the results. In both healthy and APL patients, AA was the most frequent genotype in rs1360485 followed by AG and GG. CC, CG, and GG were the most frequent genotypes in rs2249825 polymorphism in the order mentioned. CC was more frequent than CT, and CT was more frequent than TT in rs1060348. There was no correlation between HMGB1 polymorphisms and the incidence of differentiation syndrome based on genetic models (p-value > 0.05). As a result, HMGB1 polymorphisms are not probably associated with DS development in APL patients treated with ATRA and ATO.

Targeting MDSCs using ATRA: a phase I/II clinical trial combining pembrolizumab and all-trans retinoic acid for metastatic melanoma

Myeloid-derived suppressor cells (MDSCs) are potent suppressors of antitumor immunity and are commonly associated with poor outcomes in melanoma patients treated with immune checkpoint inhibitors. Inducing the differentiation of MDSCs using all-trans retinoic acid (ATRA) alters their activity and reduces MDSC frequency. This trial seeks to assess the safety and efficacy of combining ATRA and pembrolizumab in metastatic melanoma patients. In 24 stage IV melanoma patients, treatment with pembrolizumab Q3W plus the supplemental treatment of ATRA orally for three days surrounding each of the first four pembrolizumab infusions effectively lowered the frequency of circulating PMN-MDSCs and enhanced melanoma-specific T cell activity. The combination was well tolerated. Median progression free survival was 20.3 months, and the overall response rate was 71%, with 50% of patients experiencing a complete response. Targeting MDSCs remains a promising mechanism to enhance the efficacy of anti-PD-1 therapies and this combination merits further investigation.

Pseudotumor Cerebri in the Setting of Differentiation Syndrome in a Patient with Acute Promyelocytic Leukemia Treated with All-trans Retinoic Acid During Induction Therapy

Introduction: Differentiation syndrome, a well-known complication of all-trans retinoic acid (ATRA) in patients with acute promyelocytic leukemia (APML), can very rarely have ophthalmic manifestations. Pseudotumor cerebri (PC) in the setting of differentiation syndrome (DS) in patients undergoing induction with all-trans retinoic acid has rarely been reported elsewhere. We herein report one such case. Case Presentation: A 28-year-old, non-obese female diagnosed as acute promyelocytic leukemia underwent induction with all- trans retinoic acid and Idarubicin. On day 4 of the treatment, she developed high grade fever (104 – 105 F), dry cough, hypotension, tachycardia, and tinnitus. Chest X ray showed floppy shadows in bilateral lungs. On physical examination, bilateral lower limb edema was noted. She also experienced sudden weight gain of 5 kilogram in 48 hours. After careful exclusion of systemic infection, she was suspected as having DS. She also noticed a reduction in vision in right eye. On eye examination, her best-corrected visual acuity (VA) was 6/60 in the right eye (RE) and 6/6 in the left eye (LE). Fundus evaluation revealed bilateral disc edema with peripapillary hemorrhages along with slight tortuosity of vessels and a yellowish lesion over the fovea in RE. Suspecting DS, she was treated with injection dexamethasone 10 mg twice daily and all- trans retinoic acid was temporarily discontinued. Immediately after its discontinuation, her headache lessened and vision improved gradually. After 2 weeks, her VA was 6/12 in RE and 6/6 in LE which improved to 6/6 in both eyes at 3 months. The patient was also receiving oral voriconazole for fungal prophylaxis and the potentiation effect of all- trans retinoic acid could thus be explained. Conclusion: Pseudotumor cerebri associated with all-trans retinoic acid treatment in acute promyelocytic leukemia, even though frequently reported in pediatric patients, is rare in adults. Ophthalmological evaluation is mandatory in all these patients under all-trans retinoic acid therapy.