Neuropilin-1 Is an Important Niche Component and Exerts Context-Dependent Effects on Hematopoietic Stem Cells

2017 ◽  
Vol 26 (1) ◽  
pp. 35-48 ◽  
Author(s):  
Suprita S. Ghode ◽  
Manmohan S. Bajaj ◽  
Rohan S. Kulkarni ◽  
Lalita S. Limaye ◽  
Yogesh S. Shouche ◽  
...  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christina M. Termini ◽  
Amara Pang ◽  
Tiancheng Fang ◽  
Martina Roos ◽  
Vivian Y. Chang ◽  
...  

AbstractIonizing radiation and chemotherapy deplete hematopoietic stem cells and damage the vascular niche wherein hematopoietic stem cells reside. Hematopoietic stem cell regeneration requires signaling from an intact bone marrow (BM) vascular niche, but the mechanisms that control BM vascular niche regeneration are poorly understood. We report that BM vascular endothelial cells secrete semaphorin 3 A (SEMA3A) in response to myeloablation and SEMA3A induces p53 – mediated apoptosis in BM endothelial cells via signaling through its receptor, Neuropilin 1 (NRP1), and activation of cyclin dependent kinase 5. Endothelial cell – specific deletion of Nrp1 or Sema3a or administration of anti-NRP1 antibody suppresses BM endothelial cell apoptosis, accelerates BM vascular regeneration and concordantly drives hematopoietic reconstitution in irradiated mice. In response to NRP1 inhibition, BM endothelial cells increase expression and secretion of the Wnt signal amplifying protein, R spondin 2. Systemic administration of anti - R spondin 2 blocks HSC regeneration and hematopoietic reconstitution which otherwise occurrs in response to NRP1 inhibition. SEMA3A – NRP1 signaling promotes BM vascular regression following myelosuppression and therapeutic blockade of SEMA3A – NRP1 signaling in BM endothelial cells accelerates vascular and hematopoietic regeneration in vivo.


Blood ◽  
1999 ◽  
Vol 94 (7) ◽  
pp. 2301-2309 ◽  
Author(s):  
Rafaèle Tordjman ◽  
Nathalie Ortéga ◽  
Laure Coulombel ◽  
Jean Plouët ◽  
Paul-Henri Roméo ◽  
...  

In adult bone marrow, hematopoietic stem cells are found in close association with distinctive stromal cell elements. This association is necessary for maintenance of hematopoiesis, but the precise mechanisms underlying the cross-talk between stromal cells and hematopoietic stem cells are poorly understood. In this study, we used a bone marrow stromal cell line (MS-5) that is able to support human long-term hematopoiesis. This hematopoietic-promoting activity cannot be related to expression of known cytokines and is abolished by addition of hydrocortisone. Using a gene trap strategy that selects genes encoding transmembrane or secreted proteins expressed by MS-5 cells, we obtained several insertions that produced fusion proteins. In one clone, fusion protein activity was downregulated in the presence of hydrocortisone, and we show that insertion of the trap vector has occurred into the neuropilin-1 gene. Neuropilin-1 is expressed in MS-5 cells, in other hematopoietic-supporting cell lines, and in primary stromal cells but not in primitive hematopoietic cells. We show that neuropilin-1 acts as a functional cell-surface receptor in MS-5 cells. Two neuropilin-1 ligands, semaphorin III and VEGF 165, can bind to these cells, and the addition of VEGF 165 to MS-5 cells increases expression of 2 cytokines known to regulate early hematopoiesis, Tpo and Flt3-L. Finally, we show that stromal cells and immature hematopoietic cells express different neuropilin-1 ligands. We propose that neuropilin-1 may act as a novel receptor on stromal cells by mediating interactions between stroma and primitive hematopoietic cells.


2006 ◽  
Author(s):  
Hideyo Hirai ◽  
Pu Zhang ◽  
Tajhal Dayaram ◽  
Christopher Hetherington ◽  
Shin-ichi Mizuno ◽  
...  

Author(s):  
И.Ю. Маклакова ◽  
Д.Ю. Гребнев ◽  
А.П. Ястребов

Цель - изучение влияния сочетанной трансплантации мультипотентных мезенхимальных стромальных (ММСК) и гемопоэтических стволовых клеток (ГСК), выделенных из плаценты, на регенерацию белой и красной пульпы селезенки в физиологических условиях и в условиях воздействия ионизующего излучения. Методика. Эксперименты выполнены белых лабораторных беспородных мышах-самцах. Облучение животных проводилось на гамма-терапевтической установке типа АГАТ-С с радионуклидным источником Co-60 типа ГИК-8-4, поглощенная доза составила 4,0 Гр, мощность поглощенной дозы 20 сГр/мин. Животным опытной группы внутривенно вводились аллогенные ММСК и ГСК соответственно в дозе 6 млн клеток/кг и 330 тыс. клеток/кг, суспендированные в 0,2 мл 0,9% раствора NaCl. Выделение гемопоэтических стволовых клеток осуществлялось методом прямой иммуномагнитной сепарации. Проводили морфометрию лимфоидных фолликулов селезенки (средняя площадь, средняя площадь В-зоны, средняя площадь герминативного центра, средняя площадь T-зоны), а также определялось среднее расстояние между центрами фолликулов и средняя клеточность красной пульпы. Результаты. Показано, что после воздействия ионизирующего излучения на фоне сочетанной трансплантации ММСК и ГСК происходит увеличение размеров лимфоидного фолликула за счет площади B-зоны фолликула, площади герминативного центра фолликула, восстановление содержания лимфобластов, пролимфоцитов и лимфоцитов до значений нормы. На фоне трансплантации ММСК и ГСК в условиях лучевой нагрузки установлено увеличение плотности клеток в красной пульпе селезенки и, как следствие, увеличение расстояния между центрами лимфоидных фолликулов. Увеличение плотности клеток в красной пульпе происходит как за счет увеличения содержания эритроидных клеток, так и за счет увеличения гранулоцитов. Заключение. Проведенные исследования свидетельствуют об эффективности сочетанной трансплантации ММСК и ГСК в отношении основных морфометрических показателей селезенки после воздействия ионизирующего излучения. The purpose of this work was to study the effect of combined transplantation of multipotent mesenchymal stromal (MSCS) and hematopoietic stem cells (HSCs) isolated from the placenta, on the regeneration of white and red pulp of the spleen under physiological conditions and in conditions of exposure to ionizing radiation. Methods. The experiments were performed with laboratory mice-males. We studied the influence of ionizing radiation dose of 4.0 Gy. Animals of the experimental group were intravenously infused into MMSC and GSK respectively at a dose of 6 million cells/kg and 330 thousand cells/kg, suspended in 0.2 ml of 0.9% NaCl solution. The selection of hematopoietic stem cells was carried out using the direct technique of immune magnetic separation. Were studied the following morphometric parameters of the spleen: the average area of lymphoid follicles, the average area of zone of lymphoid follicles, average size of germinal center of lymphoid follicles, average size T-zones of lymphoid follicles, the average distance between the centers of the follicles, the average cellularity of the red pulp. Results. As a result, of research obtained that after exposure to ionizing radiation on the background of combined transplantation of HSC and MSCS there is an increase in size of lymphoid follicle at the expense of area B-zone of the follicle, the area germinative center of the follicle, restoring the content of lymphoblasts and lymphoblasts and lymphocytes to normal values. On the background of transplantation MMSC and GSK in terms of radiation exposure changes and the red pulp of the spleen. The increase in the density of cells in the red pulp of the spleen and, as a consequence, of the increase of the distance between the centers of lymphoid follicles. The increase in the density of cells in the red pulp occurs due to the increase in the content of erythroid cells and by increasing granulocytes. Key words: ionizing radiation, multipotent mesenchymal stromal cells, hematopoietic stem cells, spleen, regeneration. Conclusion. Studies have shown the effectiveness of combined transplantation MSC and GSK in respect of the main morphometric parameters of the spleen after exposure to ionizing radiation.


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