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Comparison of immature and mature bone marrow-derived dendritic cells by atomic force microscopy.

Xing F, Wang J, Hu M, Yu Y, Chen G, Liu J - Nanoscale Res Lett (2011)

Bottom Line: AFM images revealed that the immature BMDCs treated by granulocyte macrophage-colony stimulating factor plus IL-4 mainly appeared round with smooth surface, whereas the mature BMDCs induced by lipopolysaccharide displayed an irregular shape with numerous pseudopodia or lamellapodia and ruffles on the cell membrane besides becoming larger, flatter, and longer.The nano-features of the mature BMDCs were supported by a high level of IL-12 produced from the mature BMDCs and high expression of MHC-II on the surface of them.These findings provide a new insight into the nanostructure of the immature and mature BMDCs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China. tfyxing@jnu.edu.cn.

ABSTRACT
A comparative study of immature and mature bone marrow-derived dendritic cells (BMDCs) was first performed through an atomic force microscope (AFM) to clarify differences of their nanostructure and adhesion force. AFM images revealed that the immature BMDCs treated by granulocyte macrophage-colony stimulating factor plus IL-4 mainly appeared round with smooth surface, whereas the mature BMDCs induced by lipopolysaccharide displayed an irregular shape with numerous pseudopodia or lamellapodia and ruffles on the cell membrane besides becoming larger, flatter, and longer. AFM quantitative analysis further showed that the surface roughness of the mature BMDCs greatly increased and that the adhesion force of them was fourfold more than that of the immature BMDCs. The nano-features of the mature BMDCs were supported by a high level of IL-12 produced from the mature BMDCs and high expression of MHC-II on the surface of them. These findings provide a new insight into the nanostructure of the immature and mature BMDCs.

No MeSH data available.


Related in: MedlinePlus

Adhesive force of immature and mature BMDCs. (A) As shown in Figure 5A (slightly modified from Shahin et al.[29,30]), the AFM tip is moved toward the cell surface (1) and then retracted at a constant lateral position (2) and (3). During the AFM tip retraction, the AFM tip with the sample leads to a force signal with a distinct shape (4). The force increases until bond rupture occurs (5) at an unbinding force; (B a and b) The typical force-distance curves were recorded with using an non-functionalized AFM tip to measure the adhesive force of the immature BMDCs treated with 10.0 μg/L of GM-CSF plus 10.0 μg/L of IL-4 (B a) or the mature BMDCs stimulated with 1.0 mg/L of LPS (B b). The measured adhesion force (352.37 ± 11.71 pN) on the membrane surface of the mature BMDCs was much bigger than that (70.37 ± 4.55 pN) of the immature BMDCs (n = 10; P < 0.01).
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Figure 5: Adhesive force of immature and mature BMDCs. (A) As shown in Figure 5A (slightly modified from Shahin et al.[29,30]), the AFM tip is moved toward the cell surface (1) and then retracted at a constant lateral position (2) and (3). During the AFM tip retraction, the AFM tip with the sample leads to a force signal with a distinct shape (4). The force increases until bond rupture occurs (5) at an unbinding force; (B a and b) The typical force-distance curves were recorded with using an non-functionalized AFM tip to measure the adhesive force of the immature BMDCs treated with 10.0 μg/L of GM-CSF plus 10.0 μg/L of IL-4 (B a) or the mature BMDCs stimulated with 1.0 mg/L of LPS (B b). The measured adhesion force (352.37 ± 11.71 pN) on the membrane surface of the mature BMDCs was much bigger than that (70.37 ± 4.55 pN) of the immature BMDCs (n = 10; P < 0.01).

Mentions: Operational principle of AFM was schematically shown in Figure 5A. Schematic representation of a typical force-distance cycle was used to display the full process of measuring cell adhesion force. The tip was moved toward the cell surface (1) and (2), and then retracted at a constant lateral position (3). During tip approach, the tip with the sample leaded to a force signal with a distinct shape (4) during tip retraction. The force increased until bond rupture occurred (5) at an unbinding force [28-30]. Two force-distance curves recorded between the silicon nitride probe and the surface of the BMDCs were shown in Figure 5. Force-distance curve measurement demonstrated that the changes in the immature or mature BDMC surface nanostructure went along with profound modification of the nanomechanical property. Upon approach, no significant deviation from linearity was seen in the contact region of the immature BDMCs, indicating that the sample was not deformed by the probe. Upon retraction, the adhesion force was detected, reflecting the absence of molecular interaction between both probe and surface. In contrast with the immature BDMCs, the mature BDMCs revealed a curvature upon approach, reflecting sample softness and/or repulsive surface forces. This might be due to electrostatic interaction. Furthermore, silicon nitride surface was shown to be close to electrical neutrality over a wide pH range (pH 6 to 8.5). The heterogeneous surface of BDMCs after addition of GM-CSF or LPS was directly correlated with differences in adhesion force revealed by retraction curves. The weak adhesion force was measured between the probe and the immature BDMC surface, being around 50 to 80 pN (Figure 5B a), while great adhesion force was determined on the mature BDMCs, being fourfold bigger than the former (n = 10 cells for each group) (Figure 5B b). All of the 256 force-distance curves recorded showed the same feature, indicating that the sample surface was homogeneous as regards the nanomechanical property. It has been proved that polysaccharides play a key role in cellular adhesion [31]. Thus, the increased adhesion force on the surface of the mature BDMCs might be attributed to the presence of polysaccharide aggregation and mechanically beneficial to deformation, movement, migration, adhesion, and interaction of the mature BMDCs, which may adapt to functional changes of them. In addition, it should be pointed out that adhesive force-distance curve measurement was processed only using fixed BMDCs due to the limitation of the used instrument. Therefore, it is reasonably speculated that the measured adhesive force might be smaller than that under the physiological state of living BMDCs. Obviously, BMDCs growing in culture medium merit to be directly observed to explore it using a more advanced AFM. Moreover, antigen-antibody interaction force on the surface of mature BMDCs remains investigated further by using chemically modified probes. This would provide a new insight into molecular mechanisms of bio-interfacial phenomena, including aggregation, adhesion, molecular recognition, and intercellular communication of the mature BMDCs.


Comparison of immature and mature bone marrow-derived dendritic cells by atomic force microscopy.

Xing F, Wang J, Hu M, Yu Y, Chen G, Liu J - Nanoscale Res Lett (2011)

Adhesive force of immature and mature BMDCs. (A) As shown in Figure 5A (slightly modified from Shahin et al.[29,30]), the AFM tip is moved toward the cell surface (1) and then retracted at a constant lateral position (2) and (3). During the AFM tip retraction, the AFM tip with the sample leads to a force signal with a distinct shape (4). The force increases until bond rupture occurs (5) at an unbinding force; (B a and b) The typical force-distance curves were recorded with using an non-functionalized AFM tip to measure the adhesive force of the immature BMDCs treated with 10.0 μg/L of GM-CSF plus 10.0 μg/L of IL-4 (B a) or the mature BMDCs stimulated with 1.0 mg/L of LPS (B b). The measured adhesion force (352.37 ± 11.71 pN) on the membrane surface of the mature BMDCs was much bigger than that (70.37 ± 4.55 pN) of the immature BMDCs (n = 10; P < 0.01).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211875&req=5

Figure 5: Adhesive force of immature and mature BMDCs. (A) As shown in Figure 5A (slightly modified from Shahin et al.[29,30]), the AFM tip is moved toward the cell surface (1) and then retracted at a constant lateral position (2) and (3). During the AFM tip retraction, the AFM tip with the sample leads to a force signal with a distinct shape (4). The force increases until bond rupture occurs (5) at an unbinding force; (B a and b) The typical force-distance curves were recorded with using an non-functionalized AFM tip to measure the adhesive force of the immature BMDCs treated with 10.0 μg/L of GM-CSF plus 10.0 μg/L of IL-4 (B a) or the mature BMDCs stimulated with 1.0 mg/L of LPS (B b). The measured adhesion force (352.37 ± 11.71 pN) on the membrane surface of the mature BMDCs was much bigger than that (70.37 ± 4.55 pN) of the immature BMDCs (n = 10; P < 0.01).
Mentions: Operational principle of AFM was schematically shown in Figure 5A. Schematic representation of a typical force-distance cycle was used to display the full process of measuring cell adhesion force. The tip was moved toward the cell surface (1) and (2), and then retracted at a constant lateral position (3). During tip approach, the tip with the sample leaded to a force signal with a distinct shape (4) during tip retraction. The force increased until bond rupture occurred (5) at an unbinding force [28-30]. Two force-distance curves recorded between the silicon nitride probe and the surface of the BMDCs were shown in Figure 5. Force-distance curve measurement demonstrated that the changes in the immature or mature BDMC surface nanostructure went along with profound modification of the nanomechanical property. Upon approach, no significant deviation from linearity was seen in the contact region of the immature BDMCs, indicating that the sample was not deformed by the probe. Upon retraction, the adhesion force was detected, reflecting the absence of molecular interaction between both probe and surface. In contrast with the immature BDMCs, the mature BDMCs revealed a curvature upon approach, reflecting sample softness and/or repulsive surface forces. This might be due to electrostatic interaction. Furthermore, silicon nitride surface was shown to be close to electrical neutrality over a wide pH range (pH 6 to 8.5). The heterogeneous surface of BDMCs after addition of GM-CSF or LPS was directly correlated with differences in adhesion force revealed by retraction curves. The weak adhesion force was measured between the probe and the immature BDMC surface, being around 50 to 80 pN (Figure 5B a), while great adhesion force was determined on the mature BDMCs, being fourfold bigger than the former (n = 10 cells for each group) (Figure 5B b). All of the 256 force-distance curves recorded showed the same feature, indicating that the sample surface was homogeneous as regards the nanomechanical property. It has been proved that polysaccharides play a key role in cellular adhesion [31]. Thus, the increased adhesion force on the surface of the mature BDMCs might be attributed to the presence of polysaccharide aggregation and mechanically beneficial to deformation, movement, migration, adhesion, and interaction of the mature BMDCs, which may adapt to functional changes of them. In addition, it should be pointed out that adhesive force-distance curve measurement was processed only using fixed BMDCs due to the limitation of the used instrument. Therefore, it is reasonably speculated that the measured adhesive force might be smaller than that under the physiological state of living BMDCs. Obviously, BMDCs growing in culture medium merit to be directly observed to explore it using a more advanced AFM. Moreover, antigen-antibody interaction force on the surface of mature BMDCs remains investigated further by using chemically modified probes. This would provide a new insight into molecular mechanisms of bio-interfacial phenomena, including aggregation, adhesion, molecular recognition, and intercellular communication of the mature BMDCs.

Bottom Line: AFM images revealed that the immature BMDCs treated by granulocyte macrophage-colony stimulating factor plus IL-4 mainly appeared round with smooth surface, whereas the mature BMDCs induced by lipopolysaccharide displayed an irregular shape with numerous pseudopodia or lamellapodia and ruffles on the cell membrane besides becoming larger, flatter, and longer.The nano-features of the mature BMDCs were supported by a high level of IL-12 produced from the mature BMDCs and high expression of MHC-II on the surface of them.These findings provide a new insight into the nanostructure of the immature and mature BMDCs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China. tfyxing@jnu.edu.cn.

ABSTRACT
A comparative study of immature and mature bone marrow-derived dendritic cells (BMDCs) was first performed through an atomic force microscope (AFM) to clarify differences of their nanostructure and adhesion force. AFM images revealed that the immature BMDCs treated by granulocyte macrophage-colony stimulating factor plus IL-4 mainly appeared round with smooth surface, whereas the mature BMDCs induced by lipopolysaccharide displayed an irregular shape with numerous pseudopodia or lamellapodia and ruffles on the cell membrane besides becoming larger, flatter, and longer. AFM quantitative analysis further showed that the surface roughness of the mature BMDCs greatly increased and that the adhesion force of them was fourfold more than that of the immature BMDCs. The nano-features of the mature BMDCs were supported by a high level of IL-12 produced from the mature BMDCs and high expression of MHC-II on the surface of them. These findings provide a new insight into the nanostructure of the immature and mature BMDCs.

No MeSH data available.


Related in: MedlinePlus