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Suppressor of Cytokine Signaling 2 Negatively Regulates NK Cell Differentiation by Inhibiting JAK2 Activity

View Article: PubMed Central - PubMed

ABSTRACT

Suppressor of cytokine signaling (SOCS) proteins are negative regulators of cytokine responses. Although recent reports have shown regulatory roles for SOCS proteins in innate and adaptive immunity, their roles in natural killer (NK) cell development are largely unknown. Here, we show that SOCS2 is involved in NK cell development. SOCS2−/− mice showed a high frequency of NK cells in the bone marrow and spleen. Knockdown of SOCS2 was associated with enhanced differentiation of NK cells in vitro, and the transplantation of hematopoietic stem cells (HSCs) into congenic mice resulted in enhanced differentiation in SOCS2−/− HSCs. We found that SOCS2 could inhibit Janus kinase 2 (JAK2) activity and JAK2-STAT5 signaling pathways via direct interaction with JAK2. Furthermore, SOCS2−/− mice showed a reduction in lung metastases and an increase in survival following melanoma challenge. Overall, our findings suggest that SOCS2 negatively regulates the development of NK cells by inhibiting JAK2 activity via direct interaction.

No MeSH data available.


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Increased tumor surveillance of NK cells in SOCS2−/− mice.(A,B) Lung metastasis of WT or SOCS2−/− mice was analyzed at 14 days after intravenous injection of B16F10 cells. Representative images of the lung (A) and the number of melanoma nodules on the surface of lung (B) are shown. (C) Representative images of flow cytometric analysis of lung-infiltrating NK, NKT, and CD8+ T cells are shown (n = 4). (D,E) Bar graphs show the percentage (D) or absolute numbers (E) of NK (CD3−NK1.1+) cells, NKT (CD3+NK1.1+) and CD8+T (CD3+NK1.1−) cells in the lungs (n = 4). (F) Mice survival assay. Survival rate were measured from day 0 to day 30 after melanoma injection (n = 10). The experiment shown is representative of three experiments. Statistical significance is indicates as *p < 0.05, **p < 0.01.
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f8: Increased tumor surveillance of NK cells in SOCS2−/− mice.(A,B) Lung metastasis of WT or SOCS2−/− mice was analyzed at 14 days after intravenous injection of B16F10 cells. Representative images of the lung (A) and the number of melanoma nodules on the surface of lung (B) are shown. (C) Representative images of flow cytometric analysis of lung-infiltrating NK, NKT, and CD8+ T cells are shown (n = 4). (D,E) Bar graphs show the percentage (D) or absolute numbers (E) of NK (CD3−NK1.1+) cells, NKT (CD3+NK1.1+) and CD8+T (CD3+NK1.1−) cells in the lungs (n = 4). (F) Mice survival assay. Survival rate were measured from day 0 to day 30 after melanoma injection (n = 10). The experiment shown is representative of three experiments. Statistical significance is indicates as *p < 0.05, **p < 0.01.

Mentions: NK cells are well known for their tumor-suppressive role3536. To investigate whether loss of SOCS2 affects NK cell-mediated anti-tumor activity in vivo, we challenged WT and SOCS2−/− mice with B16F10 melanoma cells37. After 14 d, the experiment was terminated and lung metastases were counted. As shown Fig. 8A and B, WT mice showed extensive metastatic nodule formation in their lungs, while B16F10 metastatic nodules were largely absent in SOCS2−/− mice. Next, we analyzed the infiltrated immune cells of lung at 14 days using flow cytometry. The frequency and absolute numbers of NK cells were markedly increased in SOCS2−/− mice, whereas NKT cells and CD8+ T cells were not increased (Fig. 8C–E). To clarify the reason for increased infiltration of NK cells in the metastatic lungs, we analyzed the frequency of NK cells in the lungs of WT and SOCS2−/− mice. Interestingly, the frequency of NK cells in SOCS2−/− mice were increased in the lungs (Fig. S4A,B). Next, to identify NK cell migration, we transferred purified CD45.2+ WT or SOCS2−/− NK cells into CD45.1+ recipients and assessed distribution of infiltrated NK cells in the lungs. The frequency of adoptively transferred NK cells migrated into the lung was not different between WT and SOCS2−/− mice (Fig. S4C–E). These results imply that reduction of lung metastasis might be associated with increased number of NK cells in SOCS2−/− mice. Furthermore, SOCS2−/− mice survived longer than WT mice following B16F10 challenge (Fig. 8F). These data revealed that NK cells performed enhanced tumor surveillance in SOCS2−/− mice.


Suppressor of Cytokine Signaling 2 Negatively Regulates NK Cell Differentiation by Inhibiting JAK2 Activity
Increased tumor surveillance of NK cells in SOCS2−/− mice.(A,B) Lung metastasis of WT or SOCS2−/− mice was analyzed at 14 days after intravenous injection of B16F10 cells. Representative images of the lung (A) and the number of melanoma nodules on the surface of lung (B) are shown. (C) Representative images of flow cytometric analysis of lung-infiltrating NK, NKT, and CD8+ T cells are shown (n = 4). (D,E) Bar graphs show the percentage (D) or absolute numbers (E) of NK (CD3−NK1.1+) cells, NKT (CD3+NK1.1+) and CD8+T (CD3+NK1.1−) cells in the lungs (n = 4). (F) Mice survival assay. Survival rate were measured from day 0 to day 30 after melanoma injection (n = 10). The experiment shown is representative of three experiments. Statistical significance is indicates as *p < 0.05, **p < 0.01.
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Related In: Results  -  Collection

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f8: Increased tumor surveillance of NK cells in SOCS2−/− mice.(A,B) Lung metastasis of WT or SOCS2−/− mice was analyzed at 14 days after intravenous injection of B16F10 cells. Representative images of the lung (A) and the number of melanoma nodules on the surface of lung (B) are shown. (C) Representative images of flow cytometric analysis of lung-infiltrating NK, NKT, and CD8+ T cells are shown (n = 4). (D,E) Bar graphs show the percentage (D) or absolute numbers (E) of NK (CD3−NK1.1+) cells, NKT (CD3+NK1.1+) and CD8+T (CD3+NK1.1−) cells in the lungs (n = 4). (F) Mice survival assay. Survival rate were measured from day 0 to day 30 after melanoma injection (n = 10). The experiment shown is representative of three experiments. Statistical significance is indicates as *p < 0.05, **p < 0.01.
Mentions: NK cells are well known for their tumor-suppressive role3536. To investigate whether loss of SOCS2 affects NK cell-mediated anti-tumor activity in vivo, we challenged WT and SOCS2−/− mice with B16F10 melanoma cells37. After 14 d, the experiment was terminated and lung metastases were counted. As shown Fig. 8A and B, WT mice showed extensive metastatic nodule formation in their lungs, while B16F10 metastatic nodules were largely absent in SOCS2−/− mice. Next, we analyzed the infiltrated immune cells of lung at 14 days using flow cytometry. The frequency and absolute numbers of NK cells were markedly increased in SOCS2−/− mice, whereas NKT cells and CD8+ T cells were not increased (Fig. 8C–E). To clarify the reason for increased infiltration of NK cells in the metastatic lungs, we analyzed the frequency of NK cells in the lungs of WT and SOCS2−/− mice. Interestingly, the frequency of NK cells in SOCS2−/− mice were increased in the lungs (Fig. S4A,B). Next, to identify NK cell migration, we transferred purified CD45.2+ WT or SOCS2−/− NK cells into CD45.1+ recipients and assessed distribution of infiltrated NK cells in the lungs. The frequency of adoptively transferred NK cells migrated into the lung was not different between WT and SOCS2−/− mice (Fig. S4C–E). These results imply that reduction of lung metastasis might be associated with increased number of NK cells in SOCS2−/− mice. Furthermore, SOCS2−/− mice survived longer than WT mice following B16F10 challenge (Fig. 8F). These data revealed that NK cells performed enhanced tumor surveillance in SOCS2−/− mice.

View Article: PubMed Central - PubMed

ABSTRACT

Suppressor of cytokine signaling (SOCS) proteins are negative regulators of cytokine responses. Although recent reports have shown regulatory roles for SOCS proteins in innate and adaptive immunity, their roles in natural killer (NK) cell development are largely unknown. Here, we show that SOCS2 is involved in NK cell development. SOCS2&minus;/&minus; mice showed a high frequency of NK cells in the bone marrow and spleen. Knockdown of SOCS2 was associated with enhanced differentiation of NK cells in vitro, and the transplantation of hematopoietic stem cells (HSCs) into congenic mice resulted in enhanced differentiation in SOCS2&minus;/&minus; HSCs. We found that SOCS2 could inhibit Janus kinase 2 (JAK2) activity and JAK2-STAT5 signaling pathways via direct interaction with JAK2. Furthermore, SOCS2&minus;/&minus; mice showed a reduction in lung metastases and an increase in survival following melanoma challenge. Overall, our findings suggest that SOCS2 negatively regulates the development of NK cells by inhibiting JAK2 activity via direct interaction.

No MeSH data available.


Related in: MedlinePlus