Involvement of BCR::ABL1 in laminin adhesion of Philadelphia chromosome-positive acute lymphoblastic leukemia through upregulation of integrin α6

BACKGROUND

Adhesion of cancer cells to extracellular matrix laminin through the integrin superfamily reportedly induces drug resistance. Heterodimers of integrin α6 (CD49f) with integrin β1 (CD29) or β4 (CD104) are major functional receptors for laminin. Higher CD49f expression is reportedly associated with a poorer response to induction therapy in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Moreover, a xenograft mouse model transplanted with primary BCP-ALL cells revealed that neutralized antibody against CD49f improved survival after chemotherapy.

AIMS

Considering the poor outcomes in Philadelphia chromosome (Ph)-positive ALL treated with conventional chemotherapy without tyrosine kinase inhibitors, we sought to investigate an involvement of the laminin adhesion.

METHODS AND RESULTS

Ph-positive ALL cell lines expressed the highest levels of CD49f among the BCP-ALL cell lines with representative translocations, while CD29 and CD104 were ubiquitously expressed in BCP-ALL cell lines. The association of Ph-positive ALL with high levels of CD49f gene expression was also confirmed in two databases of childhood ALL cohorts. Ph-positive ALL cell lines attached to laminin and their laminin-binding properties were disrupted by blocking antibodies against CD49f and CD29 but not CD104. The cell surface expression of CD49f, but not CD29 and CD104, was downregulated by imatinib treatment in Ph-positive ALL cell lines, but not in their T315I-acquired sublines. Consistently, the laminin-binding properties were disrupted by the imatinib pre-treatment in the Ph-positive ALL cell line, but not in its T315I-acquired subline.

CONCLUSION

BCR::ABL1 plays an essential role in the laminin adhesion of Ph-positive ALL cells through upregulation of CD49f.

CD61 identifies a superior population of aged murine HSCs and is required to preserve quiescence and self-renewal

ABSTRACT

Aging leads to a decline in function of hematopoietic stem cells (HSCs) and increases susceptibility to hematological disease. We found CD61 to be highly expressed in aged murine HSCs. Here, we investigate the role of CD61 in identifying distinct subpopulations of aged HSCs and assess how expression of CD61 affects stem cell function. We show that HSCs with high expression of CD61 are functionality superior and retain self-renewal capacity in serial transplantations. In primary transplantations, aged CD61High HSCs function similarly to young HSCs. CD61High HSCs are more quiescent than their CD61Low counterparts. We also show that in aged bone marrow, CD61High and CD61Low HSCs are transcriptomically distinct populations. Collectively, our research identifies CD61 as a key player in maintaining stem cell quiescence, ensuring the preservation of their functional integrity and potential during aging. Moreover, CD61 emerges as a marker to prospectively isolate a superior, highly dormant population of young and aged HSCs, making it a valuable tool both in fundamental and clinical research.

Carbohydrates and ginsenosides in shenmai injection jointly improve hematopoietic function during chemotherapy-induced myelosuppression in mice

Background

Shenmai injection (SMI), a traditional Chinese medicine (TCM) injection prepared from Red ginseng and Ophiopogon japonicus, is widely used in clinics to treat chemotherapy-induced myelosuppression. Similar to other TCM injections, SMI contains a high amount of carbohydrates (fructose, sucrose, and maltose) in addition to the bioactive substances, specifically ginsenosides (Rg1, Re, and Rb1). To date, the role of these carbohydrates in the hematopoietic function of SMI remains unclear.

Purpose

We aimed to investigate the hematopoietic effects and potential mechanisms of SMI and its components, focusing on the carbohydrates present in SMI.

Experimental design/methods

First, we evaluated the hematopoietic effect of SMI on 5-fluorouracil (5-FU)-induced myelotoxicity in a tumor-bearing mouse model. Then we prepared mixtures of ginsenosides and carbohydrates according to their proportions in SMI and evaluated their hematopoietic function in mice with 5-FU-induced myelosuppression. Finally, hematopoiesis-related molecular networks were built based on RNA sequencing (RNA-seq) of the bone marrow stromal cells (BMSCs), and the potential mechanisms of carbohydrates and ginsenosides were evaluated.

Results

SMI attenuated 5-FU-induced myelotoxicity in tumor-bearing mice. Both ginsenosides and carbohydrates increased the bone marrow nucleated cell (BMNC) count and improved the bone marrow morphology in myelosuppressive mice; they promoted the proliferation of BMSCs derived from those myelosuppressive mice. Bioinformatics analyses revealed ECM-receptor interaction, Hippo signaling, and Wnt signaling are common pathways regulated by both ginsenosides and carbohydrates; Gstt1, Gstp2, Gsta4 and Oplah in Glutathione metabolism pathway and Cd19, Cd79a, and Cd79b in B cell receptor pathway are uniquely regulated genes related to carbohydrates but not ginsenosides.

Conclusions

Carbohydrates may collaborate with ginsenosides and contribute to the hematopoietic function of SMI. Carbohydrates could be considered as a bioactive component in this TCM injection.

Graphical Abstract

Bone Marrow Plasma Cells Modulate Local Myeloid-Lineage Differentiation via IL-10

Bone marrow plasma cells have been reported to represent a major source of IL-10; however, the impact of plasma cell derived IL-10 in that tissue remains poorly understood. We confirm in this study that even in the absence of acute immune reactions, mature plasma cells represent the dominant IL-10+ cell population in the bone marrow, and identify myeloid-lineage cells as a main local target for plasma cell derived IL-10. Using Vert-X IL-10 transcriptional reporter mice, we found that more than 50% of all IL-10+ cells in bone marrow were CD138+ plasma cells, while other IL-10+ B lineage cells were nearly absent in this organ. Accordingly, IL-10 was found in the supernatants of short-term cultures of FACS-sorted bone marrow plasma cells, confirming IL-10 secretion from these cells. IL-10+ bone marrow plasma cells showed a B220-/CD19-/MHCII low phenotype suggesting that these cells represent a mature differentiation stage. Approximately 5% of bone marrow leucocytes expressed the IL-10 receptor (IL-10R), most of them being CD115+/Ly6C+/CD11c- monocytes. Compared to littermate controls, young B lineage specific IL-10 KO mice showed increased numbers of CD115+ cells but normal populations of other myeloid cell types in bone marrow. However, at 7 months of age B lineage specific IL-10 KO mice exhibited increased populations of CD115+ myeloid and CD11c+ dendritic cells (DCs), and showed reduced F4/80 expression in this tissue; hence, indicating that bone marrow plasma cells modulate the differentiation of local myeloid lineage cells via IL-10, and that this effect increases with age. The effects of B cell/plasma cell derived IL-10 on the differentiation of CD115+, CD11c+, and F4/80+ myeloid cells were confirmed in co-culture experiments. Together, these data support the idea that IL-10 production is not limited to early plasma cell stages in peripheral tissues but is also an important feature of mature plasma cells in the bone marrow. Moreover, we provide evidence that already under homeostatic conditions in the absence of acute immune reactions, bone marrow plasma cells represent a non-redundant source for IL-10 that modulates local myeloid lineage differentiation. This is particularly relevant in older individuals.

Fabrication of biofunctionalized, cell-laden macroporous 3D PEG hydrogels as bone marrow analogs for the cultivation of human hematopoietic stem and progenitor cells

In vitro proliferation of hematopoietic stem cells (HSCs) is yet an unresolved challenge. Found in the bone marrow, HSCs can undergo self-renewing cell division and thereby multiply. Recapitulation of the bone marrow environment in order to provide the required signals for their expansion is a promising approach.Here, we describe a technique to produce biofunctionalized, macroporous poly(ethylene glycol) diacrylate (PEGDA) hydrogels that mimic the spongy 3D architecture of trabecular bones, which host the red, blood-forming bone marrow. After seeding these scaffolds with cells, they can be used as simplified bone marrow analogs for the cultivation of HSCs. This method can easily be conducted with standard laboratory chemicals and equipment. The 3D hydrogels are produced via salt leaching and biofunctionalization of the material is achieved by co-polymerizing the PEGDA with an RGD peptide. Finally, cell seeding and retrieval are described.

Hematopoietic Progenitor Cells and Cellular Microenvironment: Behavioral and Molecular Changes upon Interaction

Cell-cell contact between stem cells and cellular determinants of the microenvironment plays an essential role in controlling cell division. Using human hematopoietic progenitor cells (CD34+/CD38-) and a stroma cell line (AFT024) as a model, we have studied the initial behavioral and molecular sequel of this interaction. Time-lapse microscopy showed that CD34+/CD38- cells actively migrated toward and sought contact with stroma cells and 30% of them adhered firmly to AFT024 stroma through the uropod. CD44 and CD34 are colocalized at the site of contact. Gene expression profiles of CD34+/CD38- cells upon cultivation with or without stroma for 16, 20, 48, or 72 hours were analyzed using our human genome cDNA microarray. Chk1, egr1, and cxcl2 were among the first genes upregulated within 16 hours. Genes with the highest upregulation throughout the time course included tubulin genes, ezrin, c1qr1, fos, pcna, mcm6, ung, and dnmt1, genes that play an essential role in reorganization of the cytoskeleton system, stabilization of DNA, and methylation patterns. Our results demonstrate directed migration of CD34+/CD38- cells toward AFT024 and adhesion through the uropod and that upon interaction with supportive stroma, reorganization of the cytoskeleton system, regulation of cell division, and maintenance of genetic stability represent the most essential steps.