Differentiation Of Hematopoietic Cells Research Articles

Label-free metabolic optical biomarkers track stem cell fate transition in real time.

Tracking stem cell fate transition is crucial for understanding their development and optimizing biomanufacturing. Destructive single-cell methods provide a pseudotemporal landscape of stem cell differentiation but cannot monitor stem cell fate in real time. We established a metabolic optical metric using label-free fluorescence lifetime imaging microscopy (FLIM), feature extraction and machine learning-assisted analysis, for real-time cell fate tracking. From a library of 205 metabolic optical biomarker (MOB) features, we identified 56 associated with hematopoietic stem cell (HSC) differentiation. These features collectively describe HSC fate transition and detect its bifurcate lineage choice. We further derived a MOB score measuring the "metabolic stemness" of single cells and distinguishing their division patterns. This score reveals a distinct role of asymmetric division in rescuing stem cells with compromised metabolic stemness and a unique mechanism of PI3K inhibition in promoting ex vivo HSC maintenance. MOB profiling is a powerful tool for tracking stem cell fate transition and improving their biomanufacturing from a single-cell perspective.

Analysis of the relationship between age-related erythrocyte dysfunction and fatigue.

With the declining birth rates and aging societies in developed countries, the average age of the working population is increasing. Older people tend to get tired more easily, so prevention of fatigue is important to improve the quality of life for older workers. This study aimed to assess the mechanism of fatigue in older people, especially focused on relation between dysfunction of erythrocyte and fatigue. Total power (TP), which is the value of autonomic nerve activity, was measured as a value of fatigue and significantly decreased in workers with aging. As properties of senescent erythrocytes, the erythrocyte sedimentation rate and damaged erythrocytes population increased with aging and correlated with TP. These results suggested that the accumulation of damaged erythrocytes contributes to fatigue. Recent studies revealed that senescence-associated secretory phenotype (SASP), a phenomenon in which senescent cells secrete a variety of cytokines, affected hematopoiesis in bone marrow. We analyzed the effects of SASP factors on erythropoiesis and found that Interleukin -1α (IL-1α) suppressed erythrocyte differentiation of hematopoietic stem cells in vitro. We also showed that IL-1α levels in human blood and saliva increase with aging, suggesting the possibility that IL-1α level in saliva can be used to predict the decline in hematopoietic function.

Emerging DNA Methylome Targets in FLT3-ITD-Positive Acute Myeloid Leukemia: Combination Therapy with Clinically Approved FLT3 Inhibitors.

The internal tandem duplication (ITD) mutation of the FMS-like receptor tyrosine kinase 3 (FLT3-ITD) is the most common mutation observed in approximately 30% of acute myeloid leukemia (AML) patients. It represents poor prognosis due to continuous activation of downstream growth-promoting signaling pathways such as STAT5 and PI3K/AKT. Hence, FLT3 is considered an attractive druggable target; selective small FLT3 inhibitors (FLT3Is), such as midostaurin and quizartinib, have been clinically approved. However, patients possess generally poor remission rates and acquired resistance when FLT3I used alone. Various factors in patients could cause these adverse effects including altered epigenetic regulation, causing mainly abnormal gene expression patterns. Epigenetic modifications are required for hematopoietic stem cell (HSC) self-renewal and differentiation; however, critical driver mutations have been identified in genes controlling DNA methylation (such as DNMT3A, TET2, IDH1/2). These regulators cause leukemia pathogenesis and affect disease diagnosis and prognosis when they co-occur with FLT3-ITD mutation. Therefore, understanding the role of different epigenetic alterations in FLT3-ITD AML pathogenesis and how they modulate FLT3I's activity is important to rationalize combinational treatment approaches including FLT3Is and modulators of methylation regulators or pathways. Data from ongoing pre-clinical and clinical studies will further precisely define the potential use of epigenetic therapy together with FLT3Is especially after characterized patients' mutational status in terms of FLT3 and DNA methlome regulators.

MicroRNA target homeobox messenger RNA in HIV induced hematopoietic inhibition.

Cytopenias are a common occurrence due to abnormal hematopoiesis persistent in patients suffering from and advancing with HIV/AIDS. In order to develop efficacious therapies against cytopenias, it is necessary to understand the mechanisms by which HIV infection affects the differentiation of hematopoietic stem-progenitor cells (HSPCs), causing hematopoietic inhibition, that leads to hematological disorders. Currently, only the antiretrovirals that are being used to treat HIV infection and indirectly lower the levels of virus replication also co-attenuate cytopenias. The evidence available suggests that this indirect efficacy may not prevail for the lifetime of the infected patients, and the acquired immunodeficiency can overtake the beneficial consequences of decreased virus replication. As cited in this article, we and our colleagues are the first to make a foray into the involvement of microRNAs and their use as potential interventional treatments for the cytopenias that occur with HIV/AIDS. Herein, we progressed further in the direction of the mechanisms of the involvement of homeobox gene regulation to cause cytopenias. We had previously shown that HIV-1 inhibits multi-lineage hematopoiesis of the CD34+ cells using SCID-hu Thy/Liv animals in vivo. Furthermore, we demonstrated that the virus-induced hematopoietic inhibition occurred despite the CD34+ cells being resistant to HIV-1 infection. We set out to search for the specific host factors secreted by CD4+ T-cells that likely participate in the inhibition of hematopoiesis of the HIV infection-resistant CD34+ cells. More recently, we reported the identification of virus-infected CD4+ thymocyte-secreted miRNA-15a and miRNA-24 and that their differential expression following HIV infection causes the indirect inhibition of hematopoiesis. We then hypothesized that the observed miRNA differential expression in the virus-infected T-cells causes the abnormal regulation of homeobox (HOX) gene-encoded transcriptomes in the CD34+ cells, affecting specific MAPK signaling and CD34+ cell fate, thereby disrupting normal hematopoiesis. We present that in HIV infection, miRNA-mediated post-transcriptional dysregulation of HOXB3 mRNA inhibits multi-lineage hematopoiesis, which translates into hematological disorders in virus-infected patients with HIV/AIDS. These observations portend specific microRNA candidates for potential efficacy against the virus-induced cytopenias that are otherwise not treatable by the existing HAART/ART regimens, which are primarily designed and applicable for the attenuation of virus replication.

Analysis of blood methylation quantitative trait loci in East Asians reveals ancestry-specific impacts on complex traits.

Methylation quantitative trait loci (mQTLs) are essential for understanding the role of DNA methylation changes in genetic predisposition, yet they have not been fully characterized in East Asians (EAs). Here we identified mQTLs in whole blood from 3,523 Chinese individuals and replicated them in additional 1,858 Chinese individuals from two cohorts. Over 9% of mQTLs displayed specificity to EAs, facilitating the fine-mapping of EA-specific genetic associations, as shown for variants associated with height. Trans-mQTL hotspots revealed biological pathways contributing to EA-specific genetic associations, including an ERG-mediated 233 trans-mCpG network, implicated in hematopoietic cell differentiation, which likely reflects binding efficiency modulation of the ERG protein complex. More than 90% of mQTLs were shared between different blood cell lineages, with a smaller fraction of lineage-specific mQTLs displaying preferential hypomethylation in the respective lineages. Our study provides new insights into the mQTL landscape across genetic ancestries and their downstream effects on cellular processes and diseases/traits.

Single-cell transcriptomics dissects the transcriptome alterations of hematopoietic stem cells in myelodysplastic neoplasms

BackgroundMyelodysplastic neoplasms (MDS) are myeloid neoplasms characterized by disordered differentiation of hematopoietic stem cells and a predisposition to acute myeloid leukemia (AML). The underline pathogenesis remains unclear.MethodsIn this study, the trajectory of differentiation and mechanisms of leukemic transformation were explored through bioinformatics analysis of single-cell RNA-Seq data from hematopoietic stem and progenitor cells (HSPCs) in MDS patients.ResultsAmong the HSPC clusters, the proportion of common myeloid progenitor (CMP) was the main cell cluster in the patients with excess blasts (EB)/ secondary AML. Cell cycle analysis indicated the CMP of MDS patients were in an active proliferative state. The genes involved in the cell proliferation, such as MAML3 and PLCB1, were up-regulated in MDS CMP. Further validation analysis indicated that the expression levels of MAML3 and PLCB1 in patients with MDS-EB were significantly higher than those without EB. Patients with high expression of PLCB1 had a higher risk of transformation to AML. PLCB1 inhibitor can suppress proliferation, induce cell cycle arrest, and activate apoptosis of leukemic cells in vitro.ConclusionThis study revealed the transcriptomic change of HSPCs in MDS patients along the pseudotime and indicated that PLCB1 plays a key role in the transformation of MDS into leukemia.

The DMT1 isoform lacking the iron-response element regulates normal and malignant hematopoiesis via NOTCH pathway activation.

Natural resistance-associated macrophage protein 2 (NRAMP 2; also known as DMT1 and encoded by SLC11A2) is mainly known for its iron transport activity. Recently, the DMT1 isoform lacking the iron-response element (nonIRE) was associated with aberrant NOTCH pathway activity. In this report, we investigated the function of DMT1 nonIRE in normal and malignant hematopoiesis. Knockdown of Dmt1 nonIRE in mice showed that it has non-canonical functions in hematopoietic stem cell differentiation: its knockdown suppressed development along the myeloid and lymphoid lineages, while promoting the production of platelets. These phenotypic effects on the hematopoietic system induced by Dmt1 nonIRE knockdown were linked to suppression of Notch/Myc pathway activity. Conversely, our data indicate a non-canonical function for DMT1 nonIRE overexpression in boosting NOTCH pathway activity in T-cell leukemia homeobox protein 1 (TLX1)-defective leukemia. This work sets the stage for future investigation using a multiple-hit T-cell acute lymphoblastic leukemia (T-ALL) model to further investigate the function of DMT1 nonIRE in T-ALL disease development and progression.

Abstract SY16-01: What IDH mouse models have taught us about hematological diseases, from leukemia to T cell lymphoma

Abstract SY16-01: What IDH mouse models have taught us about hematological diseases, from leukemia to T cell lymphoma

HES6 knockdown in human hematopoietic precursor cells reduces their in vivo engraftment potential and their capacity to differentiate into erythroid cells, B cells, T cells and plasmacytoid dendritic cells.

Hematopoiesis is driven by molecular mechanisms that induce differentiation and proliferation of hematopoietic stem cells and their progeny. This involves the activity of various transcription factors, such as members of the Hairy/Enhancer of Split (HES) family, and important roles for both HES1 and HES4 have been shown in normal and malignant hematopoiesis. Here, we investigated the role of HES6 in human hematopoiesis using in vitro and in vivo models. Using bulk and scRNA-seq data, we show that HES6 is expressed during erythroid/megakaryocyte and pDC development, as well as in multipotent precursors and at specific stages of T- and B-cell development following preBCR and preTCR signalling, respectively. Consistently, knockdown of HES6 in cord blood-derived hematopoietic precursors in well-defined in vitro differentiation assays resulted in reduced differentiation of human hematopoietic precursors towards megakaryocytes, erythrocytes, pDCs, Band T-cells. In addition, HES6 knockdown HSPCs displayed reduced colony forming unit capacity in vitro and impaired potential to reconstitute hematopoiesis in vivo in a competitive transplantation assay. We demonstrate that loss of HES6 expression impacts cell cycle progression during erythroid differentiation and provide evidence for potential downstream target genes that impact these perturbations. Thus, our study uncovers new insights for a role of HES6 in human hematopoiesis.

RIO-kinase 2 is essential for hematopoiesis.

Regulation of protein synthesis is a key factor in hematopoietic stem cell maintenance and differentiation. Rio-kinase 2 (RIOK2) is a ribosome biogenesis factor that has recently been described an important regulator of human blood cell development. Additionally, we have previously identified RIOK2 as a regulator of protein synthesis and a potential target for the treatment of acute myeloid leukemia (AML). However, its functional relevance in several organ systems, including normal hematopoiesis, is not well understood. Here, we investigate the consequences of RIOK2 loss on normal hematopoiesis using two different conditional knockout mouse models. Using competitive and non-competitive bone marrow transplantations, we demonstrate that RIOK2 is essential for the differentiation of hematopoietic stem and progenitor cells (HSPCs) as well as for the maintenance of fully differentiated blood cells in vivo as well as in vitro. Loss of RIOK2 leads to rapid death in full-body knockout mice as well as mice with RIOK2 loss specific to the hematopoietic system. Taken together, our results indicate that regulation of protein synthesis and ribosome biogenesis by RIOK2 is essential for the function of the hematopoietic system.

VEGFA, VEGFR1, VEGFR2 serum and cerebrospinal fluid concentration in patients with acute leukemia

Background. Vascular endothelial growth factor A (VEGFA) is one of the most important factors for regulation of hematopoietic stem cells differentiation. It is involved in leukemogenesis and central nervous system (CNS) damage in acute leukemia. According to the literature, the VEGFA production by blast cells is increased, but the values of serum concentration and the associations with CNS involvement are contradictory.Aim. evaluate the VEGFA, VEGFR1, VEGFR2 concentration in serum and cerebrospinal fluid of patient with different types of acute leukemia in disease onset and during treatment.Materials and methods. The concentration of VEGFA in serum and cerebrospinal fluid was studied in 74 primary patients with acute leukemia. The comparison group consisted of 67 healthy donors. VEGFR1, VEGFR2 were studied in serum and cerebrospinal fluid in 34 patients at the onset of the disease. The comparison group consisted of 10 healthy donors. For the analysis, an enzyme immunoassay was used on a semi-automatic Personal Lab analyzer (Adaltis) and Affymetrix eBioscience human VEGF-A Platinum ELISA reagents.Results. Serum VEGFA concentration was statistically significantly lower in acute leukemia patients than that of donors (median 149.78 and 432.19 pg/ml respectively; p <0.0001). Factor deficiency was significantly more pronounced in patients with blastemia (p <0.015). During antitumor therapy, there was a tendency to increase the amount of the factor in the blood serum. Serum concentration of soluble VEGFR2 was also lower in patients than that of donors (6949.9 and 8795.9 pg/ml respectively; p = 0.0026). For concentration of VEGFR1 such deviations were not found. The concentrations of VEGFR1 and VEGFR2 in serum were higher than in cerebrospinal fluid (p <0.0001), while VEGFR1 showed a positive correlation between serum and cerebrospinal fluid concentrations. the concentration of VEGFR1 in the cerebrospinal fluid was significantly lower in patients with B-lymphoblastic leukemia/lymphoma compared to other types of leukemia.Conclusion. the concentration of VEGFA in serum decreases in patients with blastemia, this may indicate a lack of secretion and excessive consumption of the factor by blast cells with a decrease in the proportion of leukocytes that normally secrete the factor. In the cerebrospinal fluid, the concentrations of VEGFR1 and VEGFR2 are lower than in serum, with the lowest values being found in patients with B-lymphoblastic leukemia/lymphoma, but no relationship with the development of CNS involvement was found.

Internal m 6 A and m 7 G RNA modifications in hematopoietic system and acute myeloid leukemia.

Epitranscriptomics focuses on the RNA-modification-mediated post-transcriptional regulation of gene expression. The past decade has witnessed tremendous progress in our understanding of the landscapes and biological functions of RNA modifications, as prompted by the emergence of potent analytical approaches. The hematopoietic system provides a lifelong supply of blood cells, and gene expression is tightly controlled during the differentiation of hematopoietic stem cells (HSCs). The dysregulation of gene expression during hematopoiesis may lead to severe disorders, including acute myeloid leukemia (AML). Emerging evidence supports the involvement of the mRNA modification system in normal hematopoiesis and AML pathogenesis, which has led to the development of small-molecule inhibitors that target N6-methyladenosine (m 6 A) modification machinery as treatments. Here, we summarize the latest findings and our most up-to-date information on the roles of m 6 A and N7-methylguanine in both physiological and pathological conditions in the hematopoietic system. Furthermore, we will discuss the therapeutic potential and limitations of cancer treatments targeting m 6 A.

Gum hypertrophy in acute myeloid leukemia: an important clinical finding not to be missed

Acute myeloid leukaemia (AML) is characterized by disordered differentiation and proliferation of abnormal hematopoietic stem cells. AML usually presents with symptoms of anemia like pallor and fatigue, recurrent infections, petechiae, and mucosal bleeds. Extramedullary infiltration of leukemic cells is a common finding like proptosis or myeloid sarcoma. The occurrence of gingival hypertrophy in the pediatric age group is uncommon and usually due to inflammation followed by prolonged use of certain drugs like cyclosporin or phenytoin. Gingival infiltration in AML is rare in children, usually associated with subtypes M4/M5 (FAB classification). This case report highlights the importance of considering AML as an important differential diagnosis in cases of gum hypertrophy, as being a less common cause, it is often overlooked. Timely diagnosis and prompt treatment can be lifesaving. Here, we report two cases who presented with gum hypertrophy.

Abstract 4664: Therapeutic targeting of TP53-mutated acute myeloid leukemia by inhibiting cell cycle checkpoint

Abstract Acute myeloid leukemia (AML) is a hematological malignancy characterized by various somatic mutations leading to abnormal proliferation and differentiation of hematopoietic cells. Mutations on the TP53 gene occur in 5% to 10% of patients with de novo AML, with higher frequency in patients with relapsed and refractory (R/R) AML. Patients with TP53-mutated AML typically exhibit a poor response to conventional induction therapy and have a short overall survival (OS) rate, with a median duration of 5-9 months. Although various target agents have been developed for the treatment of AML, treatment options for TP53-mutated AML remain limited. Here, we have discovered a novel drug combination that can enhance the efficacy of the conventional therapeutic regimen for TP53-mutated AML patients. For in vitro analysis, we used the human AML cell line Kasumi-1(AML-M2), which harbors a homozygous TP53 R248Q mutation. We treated kasumi-1 cells with a combination of cytarabine and Idarubicin to produce drug tolerant persisters (DTPs) which is a minor population that survived the drug treatment. The Kasumi-1 DTPs displayed temporal G2/M phase cell cycle arrest and significant resistance to further repeated drug treatment. To discover drug candidates targeting TP53-mutated DTPs, we first examined the differentially expressed genes (DEGs) of TP53-mutated AML patients using patients’ RNA expression data deposited in the cancer genome atlas (TCGA) database. Using selected DEGs, drug candidates potentially affecting TP53-mutated AML cells were extracted from the connectivity map (CMap build 02) database. In addition, through a literature search, drugs with the ability to reactivate mutant p53, drugs that directly target mutant p53, synthetic lethal partners with mutant p53, and drugs that target leukemia stem cells were selected as candidate groups. As a result, we selected 46 drug candidates that would be effective for TP53-mutated AML through in silico analysis and therapy strategies targeting p53. Using in vitro cytotoxicity assay, we screened 46 candidate compounds at multiple doses and confirmed several drugs that effectively eliminate DTPs. The drug screening showed that cell cycle checkpoint inhibitors not only resulted in a significant reduction of G2/M phase arrested cells but also induction of apoptotic cells at the subG1 phase. Furthermore, the zero interaction potency (ZIP) model of SynergyFinder (https://synergyfinder.fimm.fi) analysis showed that cell cycle checkpoint inhibitors synergistically enhanced the cytotoxic effect of cytarabine on Kasumi-1 DTPs. Collectively, this study suggests that novel combination treatment of cell cycle checkpoint inhibitors with conventional drugs selectively inhibits TP53-mutated AML DTPs. Citation Format: Daehyeon Gwak, Dongchan Kim, Heejun Jang, Jun Liu, Suji Min, Ja Min Byun, Youngil Koh, Junshik Hong, Sung-soo Yoon, Dong-Yeop Shin, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea, Republic of. Therapeutic targeting of TP53-mutated acute myeloid leukemia by inhibiting cell cycle checkpoint [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4664.

Abstract 7224: Investigation of the efficacy of duocarmycin SA in combination with FDA approved drugs in acute myeloid leukemia cells in vitro

Abstract Acute myeloid leukemia (AML) is a hematological malignancy that is characterized by the arrest of hematopoietic stem cell differentiation, clonal expansion of myeloid hematopoietic precursors and poor patient survival outcomes. Despite therapeutic advancements, the prognosis of AML patients remains poor and improving patient survival outcomes continues to be a challenge. Therefore, the objective of this study was to investigate the efficacy of Duocarmycin SA (DSA- an antitumor antibiotic that induces DNA alkylation) in combination with FDA approved drugs currently used in the treatment of AML. In this study, DSA was evaluated in combination with doxorubicin (an anthracycline that disrupts topoisomerase II mediated DNA repair) or etoposide (a topoisomerase II inhibitor used to treat relapsed/refractory AML) in human AML cells in vitro. We hypothesized that DSA in combination with doxorubicin or etoposide would exhibit synergistic effects by improving the efficacy of both doxorubicin and etoposide in AML cells. The human AML cell lines (Molm-14 and HL60) were used for all studies. The phenotype of the cells was confirmed by flow cytometry and the IC50 of the drugs were determined using the MTT assay. Our results showed that the AML cells were CD45+, CD33+, CD13+ and CD4+. The IC50 of DSA alone for Molm-14 cells and HL60 cells were 11.12 pM and 114.8 pM, respectively. DSA alone induced DNA double-stranded breaks, significantly decreased the production of colonies and significantly increased apoptosis in AML cells in a dose-dependent manner. The IC50 of doxorubicin alone and etoposide alone was 68.6 nM and 129.7 nM, respectively. DSA in combination with the FDA approved AML drugs showed increased cytotoxic efficacy by observable decreases in AML cell viability. In summary, 1) picomolar concentrations of DSA alone was sufficient to significantly reduce AML cell viability; 2) DSA in combination with doxorubicin or etoposide significantly reduced AML cell viability and reduced the IC50 concentration of doxorubicin and etoposide. Thus, highlighting the therapeutic potential of using DSA in combination with doxorubicin or etoposide as a drug combination strategy to improve AML patient survival outcomes by decreasing the concentration of drugs necessary to treat patients and reducing off-target toxicity. Citation Format: William A. Chen, Diego Aguilar, Leena So, Yasmeen Jawhar, Nhi Nguyen, Natalie Drew, Terry G. Williams, Carlos A. Casiano, Sinisa Dovat, Kristopher Boyle, Olivia L. Francis-Boyle. Investigation of the efficacy of duocarmycin SA in combination with FDA approved drugs in acute myeloid leukemia cells in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7224.

Interleukin 3 Inhibits Glutamate-Cytotoxicity in Neuroblastoma Cell Line.

Interleukin 3 (IL-3) is a well-known pleiotropic cytokine that regulates the proliferation and differentiation of hematopoietic progenitor cells, triggering classical signaling pathways such as JAK/STAT, Ras/MAPK, and PI3K/Akt to carry out its functions. Interestingly, the IL-3 receptor is also expressed in non-hematopoietic cells, playing a crucial role in cell survival. Our previous research demonstrated the expression of the IL-3 receptor in neuron cells and its protective role in neurodegeneration. Glutamate, a principal neurotransmitter in the central nervous system, can induce cellular stress and lead to neurotoxicity when its extracellular concentrations surpass normal levels. This excessive glutamate presence is frequently observed in various neurological diseases. In this study, we uncover the protective role of IL-3 as an inhibitor of glutamate-induced cell death, analyzing the cytokine's signaling pathways during its protective effect. Specifically, we examined the relevance of JAK/STAT, Ras/MAPK, and PI3 K signaling pathways in the molecular mechanism triggered by IL-3. Our results show that the inhibition of JAK, ERK, and PI3 K signaling pathways, using pharmacological inhibitors, effectively blocked IL-3's protective role against glutamate-induced cell death. Additionally, our findings suggest that Bcl-2 and Bax proteins may be involved in the molecular mechanism triggered by IL-3. Our investigation into IL-3's ability to protect neuronal cells from glutamate-induced damage offers a promising therapeutic avenue with potential clinical implications for several neurological diseases characterized by glutamate neurotoxicity.

PHF19 before and post induction treatment possess favorable potency of reflecting treatment response to protease inhibitors, event-free survival, and overall survival in multiple myeloma patients

ABSTRACT Objective Plant homeodomain finger protein 19 (PHF19) regulates hematopoietic stem cell differentiation and promotes multiple myeloma (MM) progression. This study intended to explore the potency of PHF19 at baseline and post induction treatment in estimating treatment response to protease inhibitors and survival in MM patients. Methods This retrospective study screened 69 MM patients who received protease inhibitors with bone marrow (BM) samples available at both baseline and post induction treatment. Twenty healthy BM donors were included as healthy controls (HCs). PHF19 in plasma cells from BM was quantified by reverse transcription-quantitative polymerase chain reaction. Results PHF19 at baseline and post induction treatment in MM patients were increased than in HCs. In MM patients, PHF19 was declined post induction treatment. Elevated PHF19 at baseline and post induction treatment were correlated with renal impairment, beta-2-microglobulin ≥5.5 mg/L, t (4; 14), higher international staging system (ISS) stage, and higher revised ISS (R-ISS) stage. Concerning treatment response, PHF19 at baseline and post induction treatment were negatively associated with complete response and overall response rate. Notably, abnormal PHF19 (above 95% quantile value of PHF19 in HCs) at baseline and post induction treatment were linked with shortened event-free survival (EFS) and overall survival (OS). After adjustment, abnormal PHF19 post induction treatment was independently related to shortened EFS (hazard ratio = 2.474) and OS (hazard ratio = 3.124). Conclusion PHF19 is aberrantly high and declines post induction therapy, which simultaneously reflects unfavorable treatment response to protease inhibitors as well as shorter EFS and OS in MM patients.

Autoantibodies-Abzymes with Phosphatase Activity in Experimental Autoimmune Encephalomyelitis Mice.

The exact mechanisms of MS (multiple sclerosis) evolution are still unknown. However, the development of EAE (experimental autoimmune encephalomyelitis simulating human MS) in C57BL/6 mice occurs due to the violation of bone marrow hematopoietic stem cell differentiation profiles, leading to the production of toxic for human autoantibody splitting MBP (myelin basic protein), MOG (mouse oligodendrocyte glycoprotein), five histones, DNA, and RNA. Here, we first analyzed the changes in the relative phosphatase activity of IgGs from C57BL/6 mice blood over time, corresponding to three stages of EAE: onset, acute, and remission. Antibodies have been shown to catalyze the hydrolysis of p-nitrophenyl phosphate at several optimal pH values, mainly in the range of 6.5-7.0 and 8.5-9.5. During the spontaneous development of EAE, the most optimal value is pH 6.5. At 50 days after the birth of mice, the phosphatase activity of IgGs at pH 8.8 is 1.6-fold higher than at pH 6.5. During spontaneous development of EAE from 50 to 100 days, an increase in phosphatase activity is observed at pH 6.5 but a decrease at pH 8.8. After mice were immunized with DNA-histone complex by 20 and 60 days, phosphatase activity increased respectively by 65.3 and 109.5 fold (pH 6.5) and 128.4 and 233.6 fold (pH 8.8). Treatment of mice with MOG at the acute phase of EAE development (20 days) leads to a maximal increase in the phosphatase activity of 117.6 fold (pH 6.5) and 494.7 fold (pH 8.8). The acceleration of EAE development after mice treatment with MOG and DNA-histone complex results in increased production of lymphocytes synthesizing antibodies with phosphatase activity. All data show that IgG phosphatase activity could be essential in EAE pathogenesis.

Sialic acid in the regulation of blood cell production, differentiation and turnover.

Sialic acid is a unique sugar moiety that resides in the distal and most accessible position of the glycans on mammalian cell surface and extracellular glycoproteins and glycolipids. The potential for sialic acid to obscure underlying structures has long been postulated, but the means by which such structural changes directly affect biological processes continues to be elucidated. Here, we appraise the growing body of literature detailing the importance of sialic acid for the generation, differentiation, function and death of haematopoietic cells. We conclude that sialylation is a critical post-translational modification utilized in haematopoiesis to meet the dynamic needs of the organism by enforcing rapid changes in availability of lineage-specific cell types. Though long thought to be generated only cell-autonomously within the intracellular ER-Golgi secretory apparatus, emerging data also demonstrate previously unexpected diversity in the mechanisms of sialylation. Emphasis is afforded to the mechanism of extrinsic sialylation, whereby extracellular enzymes remodel cell surface and extracellular glycans, supported by charged sugar donor molecules from activated platelets.

Landscape of FLT3 Variations Associated with Structural and Functional Impact on Acute Myeloid Leukemia: A Computational Study.

Acute myeloid leukemia (AML) is hallmarked by the clonal proliferation of myeloid blasts. Mutations that result in the constitutive activation of the fms-like tyrosine kinase 3 (FLT3) gene, coding for a class III receptor tyrosine kinase, are significantly associated with this heterogeneous hematologic malignancy. The fms-related tyrosine kinase 3 ligand binds to the extracellular domain of the FLT3 receptor, inducing homodimer formation in the plasma membrane, leading to autophosphorylation and activation of apoptosis, proliferation, and differentiation of hematopoietic cells in bone marrow. In the present study, we evaluated the association of FLT3 as a significant biomarker for AML and tried to comprehend the effects of specific variations on the FLT3 protein's structure and function. We also examined the effects of I836 variants on binding affinity to sorafenib using molecular docking. We integrated multiple bioinformatics tools, databases, and resources such as OncoDB, UniProt, COSMIC, UALCAN, PyMOL, ProSA, Missense3D, InterProScan, SIFT, PolyPhen, and PredictSNP to annotate the structural, functional, and phenotypic impact of the known variations associated with FLT3. Twenty-nine FLT3 variants were analyzed using in silico approaches such as DynaMut, CUPSAT, AutoDock, and Discovery Studio for their impact on protein stability, flexibility, function, and binding affinity. The OncoDB and UALCAN portals confirmed the association of FLT3 gene expression and its mutational status with AML. A computational structural analysis of the deleterious variants of FLT3 revealed I863F mutants as destabilizers of the protein structure, possibly leading to functional changes. Many single-nucleotide variations in FLT3 have an impact on its structure and function. Thus, the annotation of FLT3 SNVs and the prediction of their deleterious pathogenic impact will facilitate an insight into the tumorigenesis process and guide experimental studies and clinical implications.