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Endothelial transplantation rejuvenates aged hematopoietic stem cell function.

ABSTRACT: Age-related changes in the hematopoietic compartment are primarily attributed to cell-intrinsic alterations in hematopoietic stem cells (HSCs); however, the contribution of the aged microenvironment has not been adequately evaluated. Understanding the role of the bone marrow (BM) microenvironment in supporting HSC function may prove to be beneficial in treating age-related functional hematopoietic decline. Here, we determined that aging of endothelial cells (ECs), a critical component of the BM microenvironment, was sufficient to drive hematopoietic aging phenotypes in young HSCs. We used an ex vivo hematopoietic stem and progenitor cell/EC (HSPC/EC) coculture system as well as in vivo EC infusions following myelosuppressive injury in mice to demonstrate that aged ECs impair the repopulating activity of young HSCs and impart a myeloid bias. Conversely, young ECs restored the repopulating capacity of aged HSCs but were unable to reverse the intrinsic myeloid bias. Infusion of young, HSC-supportive BM ECs enhanced hematopoietic recovery following myelosuppressive injury and restored endogenous HSC function in aged mice. Coinfusion of young ECs augmented aged HSC engraftment and enhanced overall survival in lethally irradiated mice by mitigating damage to the BM vascular microenvironment. These data lay the groundwork for the exploration of EC therapies that can serve as adjuvant modalities to enhance HSC engraftment and accelerate hematopoietic recovery in the elderly population following myelosuppressive regimens.

SUBMITTER: Poulos MG

PROVIDER: S-EPMC5663355 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Endothelial transplantation rejuvenates aged hematopoietic stem cell function.

Poulos Michael G MG Ramalingam Pradeep P Gutkin Michael C MC Llanos Pierre P Gilleran Katherine K Rabbany Sina Y SY Butler Jason M JM

The Journal of clinical investigation 20171016 11

Age-related changes in the hematopoietic compartment are primarily attributed to cell-intrinsic alterations in hematopoietic stem cells (HSCs); however, the contribution of the aged microenvironment has not been adequately evaluated. Understanding the role of the bone marrow (BM) microenvironment in supporting HSC function may prove to be beneficial in treating age-related functional hematopoietic decline. Here, we determined that aging of endothelial cells (ECs), a critical component of the BM ...[more]

PMID: 29035282

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Project description:New strategies of autologous hematopoietic stem cell transplantation (auto-HSCT) have gained much interest for the treatment of type 1 diabetes mellitus. However, assessing the clinical response and residual ?-cell function still has limitations. The aim of the study was to select the optimal quantitative index to assess pre-existing ?-cell function and to explore its predictive function for clinical response after auto-HSCT therapy. In this study, all of the patients who had undergone auto-HSCT were clustered into a responder group (??-score > 0) and a nonresponder group (??-score ? 0). We compared their quantitative metabolic indexes at baseline and performed receiver-operating characteristic (ROC) analysis to analyze the correlations between the indexes and clinical response. Kaplan-Meier analysis was conducted to compare the cumulative response durations in each quartile of the selected indexes. In an average of 15.13 ± 6.15 months of follow-up, 44 of 112 patients achieved a clinical response. The responder group had lower levels of fasting plasma glucose and quantitative insulin sensitivity check index (QUICKI) but higher levels of fasting C-peptide, fasting insulin, and homeostasis model assessments for insulin resistance (HOMA-IR). ROC analysis showed that HOMA-IR had the largest area under the curve (0.756), which was similar to that of QUICKI. Kaplan-Meier analysis further confirmed that the third quartile (1.3371-1.7018) of HOMA-IR or the second quartile (0.3523-0.3657) of QUICKI was preferential for a prolonged response. In conclusion, HOMA-IR and QUICKI could be optimal measurements for ?-cell reserves, and they were predictive for the clinical response after auto-HSCT.The ?-score was comprehensive and reliable in evaluating clinical response after autologous hematopoietic stem cell transplantation (HSCT). The homeostasis model assessments for insulin resistance and the quantitative insulin sensitivity check index could serve as precise assessments for residual ?-cell function and good predictors of clinical response. They might be used to select optimal clinical trial participants or predict the clinical response after auto-HSCT.

Project description:Hematopoietic aging is associated with decreased hematopoietic stem cell (HSC) self-renewal capacity and increased risk for myelodysplasia and leukemia. Deficient DNA repair contributes to the decline in HSC self-renewal capacity during aging and it remains unclear whether extrinsic signals can rejuvenate aged HSCs. Here, we demonstrate that augmentation of non-homologous end-joining (NHEJ) DNA repair in aged HSCs via treatment with epidermal growth factor (EGF) rejuvenates HSC function. Seven day culture of BM CD34-ckit+sca-1+lin- (34-KSL) HSCs from aged C57BL/6 mice with EGF suppressed myeloid skewing and increased production of multipotent CFU-granulocyte, erythroid, monocyte and megakaryocyte (CFU-GEMM) colonies. Aged, EGF-treated HSCs displayed increased donor multilineage engraftment in primary competitively transplanted mice and in secondary mice compared to mice transplanted with aged, control HSCs. Donor cell engraftment within the bone marrow (BM) KSL and SLAM+KSL HSC population was > 2-fold increased in mice transplanted with aged, EGF-treated HSCs. Systemic administration of EGF to aged mice for 6 weeks also increased long term – HSC self-renewal capacity as measured by increased donor bone marrow (BM) competitive repopulation in primary and secondary transplanted mice. Conversely, deletion of EGFR in Scl/Tal1+ hematopoietic cells was associated with increased myeloid skewing and depletion of LT-HSCs in middle aged mice. Mechanistically, EGF treatment decreased DNA damage in aged HSCs through activation of DNA PK-cs, Artemis and NHEJ repair. Inhibition of DNA PK-cs blocked EGF-mediated restoration of multipotent differentiation and suppression of myeloid skewing in aged HSCs, suggesting that the restoration of hematopoietic potential in aged HSCs is dependent on EGF-mediated activation of DNA PK-cs. EGF treatment also converted the transcriptome of aged HSCs from enrichment for genes involved in cell death and survival to genes involved in HSC generation and identity. These data suggest that extrinsic activation of EGFR signaling can restore key functional capacities in aged HSCs.

Project description:IntroductionHigh-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (auto-HSCT) represents a standard treatment regime for multiple myeloma (MM) patients. Common and potentially fatal side effects after auto-HSCT are infections due to a severely compromised immune system with hampered humoral and cellular immunity. This study delineates in depth the quantitative and functional B cell defects and investigates underlying extrinsic or intrinsic drivers.MethodsPeripheral blood of MM patients undergoing high-dose chemotherapy and auto-HSCT (before high-dose chemotherapy and in early reconstitution after HSCT) was studied. Absolute numbers and distribution of B cell subsets were analyzed ex vivo using flow cytometry. Additionally, B cell function was assessed with T cell dependent (TD) and T cell independent (TI) stimulation assays, analyzing proliferation and differentiation of B cells by flow cytometry and numbers of immunoglobulin secreting cells in ELISpots.ResultsQuantitative B cell defects including a shift in the B cell subset distribution occurred after auto-HSCT. Functionally, these patients showed an impaired TD as well as TI B cell immune response. Individual functional responses correlated with quantitative alterations of CD19+, CD4+, memory B cells and marginal zone-like B cells. The TD B cell function could be partially restored upon stimulation with CD40L/IL-21, successfully inducing B cell proliferation and differentiation into plasmablasts and immunoglobulin secreting cells.ConclusionQuantitative and functional B cell defects contribute to the compromised immune defense in MM patients undergoing auto-HSCT. Functional recovery upon TD stimulation and correlation with CD4+ T cell numbers, indicate these as extrinsic drivers of the functional B cell defect. Observed correlations of CD4+, CD19+, memory B and MZ-like B cell numbers with the B cell function suggest that these markers should be tested as potential biomarkers in prospective studies.

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Endothelial transplantation rejuvenates aged hematopoietic stem cell function.

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Endothelial transplantation rejuvenates aged hematopoietic stem cell function.

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