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Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation.

Bruno S, Grange C, Tapparo M, Pasquino C, Romagnoli R, Dametto E, Amoroso A, Tetta C, Camussi G - Stem Cells Int (2016)

Bottom Line: At variance with MSCs, HLSCs did not elicit NK degranulation.Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release.This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biotechnology and Health Science, University of Torino, 10126 Torino, Italy.

ABSTRACT
Human liver stem cells (HLSCs) are a mesenchymal stromal cell-like population resident in the adult liver. Preclinical studies indicate that HLSCs could be a good candidate for cell therapy. The aim of the present study was to evaluate the immunogenicity and the immunomodulatory properties of HLSCs on T-lymphocytes, natural killer cells (NKs), and dendritic cells (DCs) in allogeneic experimental settings. We found that HLSCs inhibited T-cell proliferation by a mechanism independent of cell contact and dependent on the release of prostaglandin E2 (PGE2) and on indoleamine 2,3-dioxygenase activity. When compared with mesenchymal stromal cells (MSCs), HLSCs were more efficient in inhibiting T-cell proliferation. At variance with MSCs, HLSCs did not elicit NK degranulation. Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release. When tested on DC generation from monocytes, HLSCs were found to impair DC differentiation and DCs ability to induce T-cell proliferation through PGE2. This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response.

No MeSH data available.


Related in: MedlinePlus

HLA-G expression mediates the HLSC activity on NKs. (a) Representative (n = 4) cytofluorimetric analysis of HLA-G expression on HLSC membrane and after intracytoplasmic staining, using the specific MEMG/9 antibody (native form for human HLA-G1). (b) Western Blot analyses confirmed the presence of HLA-G in HLSCs at different passages of culture (p4, p6, and p8). (c) Soluble HLA-G is present in HLSC supernatants, as indicated by Western Blot after immune-precipitation with specific antibody. HLA-G protein expression was detected through mAb 4H84, resulting in specific band corresponding to the expected molecular weight of 39 kDa. (d) Representative (n = 4) cytofluorimetric analysis of CD107a expression on NKs in degranulation assay, after 4 days of incubation with HLSCs in the presence or the absence of specific blocking antibody against HLA-G (87-G). HLSCs, via the secretion of HLA-G reduced NK degranulation, as a specific neutralizing anti-HLA-G antibody restored degranulation activity to levels similar to those following incubation of NKs with K562 cells alone (CD56+CD107+: 87 ± 5% in NK CTRL, 5.5 ± 4% in NKs cocultured with HLSCs, and 90 ± 5.3% in NKs cocultured with HLSCs in the presence of blocking antibody).
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fig4: HLA-G expression mediates the HLSC activity on NKs. (a) Representative (n = 4) cytofluorimetric analysis of HLA-G expression on HLSC membrane and after intracytoplasmic staining, using the specific MEMG/9 antibody (native form for human HLA-G1). (b) Western Blot analyses confirmed the presence of HLA-G in HLSCs at different passages of culture (p4, p6, and p8). (c) Soluble HLA-G is present in HLSC supernatants, as indicated by Western Blot after immune-precipitation with specific antibody. HLA-G protein expression was detected through mAb 4H84, resulting in specific band corresponding to the expected molecular weight of 39 kDa. (d) Representative (n = 4) cytofluorimetric analysis of CD107a expression on NKs in degranulation assay, after 4 days of incubation with HLSCs in the presence or the absence of specific blocking antibody against HLA-G (87-G). HLSCs, via the secretion of HLA-G reduced NK degranulation, as a specific neutralizing anti-HLA-G antibody restored degranulation activity to levels similar to those following incubation of NKs with K562 cells alone (CD56+CD107+: 87 ± 5% in NK CTRL, 5.5 ± 4% in NKs cocultured with HLSCs, and 90 ± 5.3% in NKs cocultured with HLSCs in the presence of blocking antibody).

Mentions: We investigated whether the expression of HLA-G molecule on HLSCs was involved in HLSC-induced inhibition of NKs. Intracellular HLA-G was detected by flow cytometry in HLSCs (69 ± 3.5%; Figure 4(a)) while only 10% of cells were positive for membrane-bound HLA-G staining. Western Blot analyses confirmed the presence of HLA-G in HLSCs at different passages of culture (Figure 4(b)). Soluble HLA-G was also present in HLSC supernatants (Figure 4(c)). Experiments with blocking antibody against HLA-G in transwells suggest that soluble HLA-G released by HLSCs is involved in the inhibitory effect on NK activity (Figure 4(d)).


Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation.

Bruno S, Grange C, Tapparo M, Pasquino C, Romagnoli R, Dametto E, Amoroso A, Tetta C, Camussi G - Stem Cells Int (2016)

HLA-G expression mediates the HLSC activity on NKs. (a) Representative (n = 4) cytofluorimetric analysis of HLA-G expression on HLSC membrane and after intracytoplasmic staining, using the specific MEMG/9 antibody (native form for human HLA-G1). (b) Western Blot analyses confirmed the presence of HLA-G in HLSCs at different passages of culture (p4, p6, and p8). (c) Soluble HLA-G is present in HLSC supernatants, as indicated by Western Blot after immune-precipitation with specific antibody. HLA-G protein expression was detected through mAb 4H84, resulting in specific band corresponding to the expected molecular weight of 39 kDa. (d) Representative (n = 4) cytofluorimetric analysis of CD107a expression on NKs in degranulation assay, after 4 days of incubation with HLSCs in the presence or the absence of specific blocking antibody against HLA-G (87-G). HLSCs, via the secretion of HLA-G reduced NK degranulation, as a specific neutralizing anti-HLA-G antibody restored degranulation activity to levels similar to those following incubation of NKs with K562 cells alone (CD56+CD107+: 87 ± 5% in NK CTRL, 5.5 ± 4% in NKs cocultured with HLSCs, and 90 ± 5.3% in NKs cocultured with HLSCs in the presence of blocking antibody).
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig4: HLA-G expression mediates the HLSC activity on NKs. (a) Representative (n = 4) cytofluorimetric analysis of HLA-G expression on HLSC membrane and after intracytoplasmic staining, using the specific MEMG/9 antibody (native form for human HLA-G1). (b) Western Blot analyses confirmed the presence of HLA-G in HLSCs at different passages of culture (p4, p6, and p8). (c) Soluble HLA-G is present in HLSC supernatants, as indicated by Western Blot after immune-precipitation with specific antibody. HLA-G protein expression was detected through mAb 4H84, resulting in specific band corresponding to the expected molecular weight of 39 kDa. (d) Representative (n = 4) cytofluorimetric analysis of CD107a expression on NKs in degranulation assay, after 4 days of incubation with HLSCs in the presence or the absence of specific blocking antibody against HLA-G (87-G). HLSCs, via the secretion of HLA-G reduced NK degranulation, as a specific neutralizing anti-HLA-G antibody restored degranulation activity to levels similar to those following incubation of NKs with K562 cells alone (CD56+CD107+: 87 ± 5% in NK CTRL, 5.5 ± 4% in NKs cocultured with HLSCs, and 90 ± 5.3% in NKs cocultured with HLSCs in the presence of blocking antibody).
Mentions: We investigated whether the expression of HLA-G molecule on HLSCs was involved in HLSC-induced inhibition of NKs. Intracellular HLA-G was detected by flow cytometry in HLSCs (69 ± 3.5%; Figure 4(a)) while only 10% of cells were positive for membrane-bound HLA-G staining. Western Blot analyses confirmed the presence of HLA-G in HLSCs at different passages of culture (Figure 4(b)). Soluble HLA-G was also present in HLSC supernatants (Figure 4(c)). Experiments with blocking antibody against HLA-G in transwells suggest that soluble HLA-G released by HLSCs is involved in the inhibitory effect on NK activity (Figure 4(d)).

Bottom Line: At variance with MSCs, HLSCs did not elicit NK degranulation.Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release.This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biotechnology and Health Science, University of Torino, 10126 Torino, Italy.

ABSTRACT
Human liver stem cells (HLSCs) are a mesenchymal stromal cell-like population resident in the adult liver. Preclinical studies indicate that HLSCs could be a good candidate for cell therapy. The aim of the present study was to evaluate the immunogenicity and the immunomodulatory properties of HLSCs on T-lymphocytes, natural killer cells (NKs), and dendritic cells (DCs) in allogeneic experimental settings. We found that HLSCs inhibited T-cell proliferation by a mechanism independent of cell contact and dependent on the release of prostaglandin E2 (PGE2) and on indoleamine 2,3-dioxygenase activity. When compared with mesenchymal stromal cells (MSCs), HLSCs were more efficient in inhibiting T-cell proliferation. At variance with MSCs, HLSCs did not elicit NK degranulation. Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release. When tested on DC generation from monocytes, HLSCs were found to impair DC differentiation and DCs ability to induce T-cell proliferation through PGE2. This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response.

No MeSH data available.


Related in: MedlinePlus