Novel combinations to improve hematopoiesis in myelodysplastic syndrome

Comparative analysis of immunological changes following realgar and arsenic trioxide treatments in a murine model of myelodysplastic syndrome

BACKGROUND

Myelodysplastic syndrome (MDS) is a prevalent hematological neoplastic disorder in clinics and its immunopathogenesis has garnered growing interest. Oral and intravenous arsenic agents have long been used to treat hematological malignancies. The main component of oral arsenic is realgar (arsenic disulfide), while arsenic trioxide is the main component of intravenous arsenic.

METHODS

This study aimed to assess the effects of ATO and Realgar on the enhancement of peripheral blood, drug safety, and T cell immune status in the NUP98-HOXD13 (NHD13) mice model of MDS, specifically in the peripheral blood, spleen, and liver.

RESULTS

The study findings indicate that realgar and arsenic trioxide (ATO) can improve peripheral hemogram in mice, whereas realgar promotes higher peripheral blood cell production than ATO. Furthermore, the clinical administration method and dose did not cause significant toxicity or side effects and thus can be considered safe. Coexistence and interconversion of hyperimmune function and immunosuppression in mice were also observed in this study. In addition, there were interactions between immune cells in the peripheral blood, spleen, and liver to regulate the immune balance of the body and activate immunity via T-cell activation.

CONCLUSION

In summary, oral and intravenous arsenic agents are beneficial in improving peripheral hemogram and immunity in mice.

Effects of immune cells in mediating the relationship between gut microbiota and myelodysplastic syndrome: a bidirectional two-sample, two-step Mendelian randomization study

BACKGROUND

The definitive establishment of a causal relationship between gut microbiota and myelodysplastic syndrome (MDS) has not been achieved. Furthermore, the involvement of immune cells in mediating the connection between gut microbiota and MDS is presently unclear.

METHODS

To elucidate the bidirectional correlation between gut microbiota and MDS, as well as to investigate the mediating role of immune cells, a bidirectional two-sample, two-step Mendelian randomization (MR) study was conducted. Summary statistics were obtained from genome-wide association studies (GWAS), including MDS (456,348 individuals), gut microbiota (18,340 individuals), and 731 immune cells signatures (3757 individuals).

RESULTS

Genetically predicted eight gut microbiota traits were significantly associated with MDS risk, but not vice versa. Through biological annotation of host-microbiome shared genes, we found that immune regulation may mediate the impact of gut microbiota on MDS. Subsequently, twenty-three immunophenotypes that exhibited significant associations with MDS risk and five of these immunophenotypes were under the causal influence of gut microbiota. Importantly, the causal effects of gut microbiota on MDS were significantly mediated by five immunophenotypes, including CD4 +T cell %leukocyte, CD127 on CD45RA - CD4 not regulatory T cell, CD45 on CD33 + HLA DR + WHR, CD33 on basophil, and Monocyte AC.

CONCLUSIONS

Gut microbiota was causally associated with MDS risk, and five specific immunophenotypes served as potential causal mediators of the effect of gut microbiota on MDS. Understanding the causality among gut microbiota, immune cells and MDS is critical in identifying potential targets for diagnosis and treatment.

The Mechanism of miR-155/miR-15b Axis Contributed to Apoptosis of CD34+ Cells by Upregulation of PD-L1 in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous myeloid clonal diseases that are characterized by ineffective bone marrow hematopoiesis. Since studies have confirmed the significance of miRNAs in ineffective hematopoiesis in MDS, the current report elucidated the mechanism mediated by miR-155-5p. The bone marrow of MDS patients was collected to detect miR-155-5p and to analyze the correlation between miR-155-5p and clinicopathological variables. Isolated bone marrow CD34+ cells were transfected with lentiviral plasmids that interfere with miR-155-5p, followed by apoptosis analysis. Finally, miR-155-5p-targeted regulation of RAC1 expression was identified, as well as the interaction between RAC1 and CREB, the co-localization of RAC1 and CREB, and the binding of CREB to miR-15b. As measured, miR-155-5p was upregulated in the bone marrow of MDS patients. Further cell experiments validated that miR-155-5p promoted CD34+ cell apoptosis. miR-155-5p could reduce the transcriptional activity of miR-15b by inhibiting RAC1, dissociating the interaction between RAC1 and CREB, and inhibiting the activation of CREB. Upregulating RAC1, CREB, or miR-15b could reduce miR-155-5p-mediated apoptosis promotion on CD34+ cells. Additionally, miR-155-5p could force PD-L1 expression, and this effect was impaired by elevating RAC1, CREB, or miR-15b. In conclusion, miR-155-5p mediates PD-L1-mediated apoptosis of CD34+ cells in MDS by RAC1/CREB/miR-15b axis, thereby inhibiting bone marrow hematopoiesis.

CD123-Directed Bispecific Antibodies for Targeting MDS Clones and Immunosuppressive Myeloid-Derived Suppressor Cells (MDSC) in High-Risk Adult MDS Patients

There is an urgent need to identify effective strategies to prevent leukemic transformation and induce sustained deep remissions in adult high-risk myelodysplastic syndrome (MDS) patients. This article discusses the clinical impact potential of bispecific antibodies (BiAB) capable of redirecting host T-cell cytotoxicity in an MHC-independent manner to malignant clones as well as immunosuppressive myeloid-derived suppressor cells (MDSC) as a new class of anti-MDS drug candidates. T-cell engaging BiAB targeting the CD123 antigen may help delay disease progression in high-risk adult MDS and potentially reduce the risk of transformation to secondary AML.

Iron in the General Population and Specificities in Older Adults: Metabolism, Causes and Consequences of Decrease or Overload, and Biological Assessment

Iron is involved in many types of metabolism, including oxygen transport in hemoglobin. Iron deficiency (ID), ie a decrease in circulating iron, can have severe consequences. We provide an update on iron metabolism and ID, highlighting the particularities in older adults (OAs). There are three iron compartments in the human body: 1) the functional compartment, which consists of heme proteins including hemoglobin, myoglobin and respiratory enzymes; 2) iron reserves (IR), which consist mainly of liver stocks and are stored as ferritin; and 3) transferrin. There are two types of ID. Absolute ID is characterized by a decrease in IR. Its main pathophysiological mechanism is bleeding, which is often digestive and can be due to neoplasia, frequent in OAs. Biological assessment shows low serum ferritin and transferrin saturation (TS) levels. Furthermore, hypochromic microcytic anemia is frequent, and the serum-soluble transferrin receptor (sTfR) level is high. Functional ID, in which IR are high or normal, is due to inflammation, which is also frequent in OAs, particularly in its chronic form. Biological assessments show high serum ferritin, normal or low TS, and normal sTfR levels. Moreover, C-reactive protein is elevated, and there is moderate non-regenerative non-macrocytic anemia. The main characteristics of iron metabolism anomalies in the elderly are the high frequency of ID (20% of ID with anemia in adults ≥85 years) and the severity of its consequences, which include cognitive impairment in case of ID or iron overload and decrease of physical activity in case of ID. In conclusion, causes of ID are frequently intertwined in OAs as a result of the polymorbidity that characterizes them. ID can have dramatic consequences, especially in frail OAs. Thus, measuring the appropriate biological markers prevents errors in the positive diagnosis of ID type, clarifies etiology, and informs treatment-related decision-making.