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Release of human cytomegalovirus from latency by a KAP1/TRIM28 phosphorylation switch.

Rauwel B, Jang SM, Cassano M, Kapopoulou A, Barde I, Trono D - Elife (2015)

Bottom Line: Here, we reveal that HCMV latency in human CD34(+) HSC reflects the recruitment on the viral genome of KAP1, a master co-repressor, together with HP1 and the SETDB1 histone methyltransferase, which results in transcriptional silencing.Correspondingly, HCMV can be forced out of latency by KAP1 knockdown or pharmacological induction of KAP1 phosphorylation, and this process can be potentiated by activating NFkB with TNF-α.These results suggest new approaches both to curtail CMV infection and to purge the virus from organ transplants.

View Article: PubMed Central - PubMed

Affiliation: School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.

ABSTRACT
Human cytomegalovirus (HCMV) is a highly prevalent pathogen that induces life-long infections notably through the establishment of latency in hematopoietic stem cells (HSC). Bouts of reactivation are normally controlled by the immune system, but can be fatal in immuno-compromised individuals such as organ transplant recipients. Here, we reveal that HCMV latency in human CD34(+) HSC reflects the recruitment on the viral genome of KAP1, a master co-repressor, together with HP1 and the SETDB1 histone methyltransferase, which results in transcriptional silencing. During lytic infection, KAP1 is still associated with the viral genome, but its heterochromatin-inducing activity is suppressed by mTOR-mediated phosphorylation. Correspondingly, HCMV can be forced out of latency by KAP1 knockdown or pharmacological induction of KAP1 phosphorylation, and this process can be potentiated by activating NFkB with TNF-α. These results suggest new approaches both to curtail CMV infection and to purge the virus from organ transplants.

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Monocytes do not differentiate during pharmacological reactivation of HCMV.After 7 days of treatment with chloroquine, monocytes were examined by FACS for the surface expression of CD1a, CD14, CD80 and CD86, analyzing results with the FlowJo software. Graphs are representative of experiments performed with cells from three different HCMV-seropositive donors.DOI:http://dx.doi.org/10.7554/eLife.06068.025
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fig7s1: Monocytes do not differentiate during pharmacological reactivation of HCMV.After 7 days of treatment with chloroquine, monocytes were examined by FACS for the surface expression of CD1a, CD14, CD80 and CD86, analyzing results with the FlowJo software. Graphs are representative of experiments performed with cells from three different HCMV-seropositive donors.DOI:http://dx.doi.org/10.7554/eLife.06068.025

Mentions: We also asked whether the pharmacological induction of KAP1 phosphorylation could trigger HCMV production from circulating monocytes. Monocytes were purified from the peripheral blood of seropositive individuals and exposed to three doses (at days 0, 3 and 5) of chloroquine, alone or in combination with Torin-1 or KU55933 (Figure 7). ATM activation did not trigger the differentiation of the monocytes into dendritic cells or macrophages, as verified by measuring the cell surface expression of CD1a, CD14, CD80 and CD86 (Figure 7—figure supplement 1). However, it induced the intracellular accumulation of HCMV DNA and the release of infectious viral particles from these monocyte populations. Furthermore, Ku55933 but not Torin-1 prevented the stimulating effect of chloroquine, as noted in HSC.10.7554/eLife.06068.024Figure 7.Inducing KAP1 phosphorylation releases HCMV from latency in monocytes.


Release of human cytomegalovirus from latency by a KAP1/TRIM28 phosphorylation switch.

Rauwel B, Jang SM, Cassano M, Kapopoulou A, Barde I, Trono D - Elife (2015)

Monocytes do not differentiate during pharmacological reactivation of HCMV.After 7 days of treatment with chloroquine, monocytes were examined by FACS for the surface expression of CD1a, CD14, CD80 and CD86, analyzing results with the FlowJo software. Graphs are representative of experiments performed with cells from three different HCMV-seropositive donors.DOI:http://dx.doi.org/10.7554/eLife.06068.025
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384640&req=5

fig7s1: Monocytes do not differentiate during pharmacological reactivation of HCMV.After 7 days of treatment with chloroquine, monocytes were examined by FACS for the surface expression of CD1a, CD14, CD80 and CD86, analyzing results with the FlowJo software. Graphs are representative of experiments performed with cells from three different HCMV-seropositive donors.DOI:http://dx.doi.org/10.7554/eLife.06068.025
Mentions: We also asked whether the pharmacological induction of KAP1 phosphorylation could trigger HCMV production from circulating monocytes. Monocytes were purified from the peripheral blood of seropositive individuals and exposed to three doses (at days 0, 3 and 5) of chloroquine, alone or in combination with Torin-1 or KU55933 (Figure 7). ATM activation did not trigger the differentiation of the monocytes into dendritic cells or macrophages, as verified by measuring the cell surface expression of CD1a, CD14, CD80 and CD86 (Figure 7—figure supplement 1). However, it induced the intracellular accumulation of HCMV DNA and the release of infectious viral particles from these monocyte populations. Furthermore, Ku55933 but not Torin-1 prevented the stimulating effect of chloroquine, as noted in HSC.10.7554/eLife.06068.024Figure 7.Inducing KAP1 phosphorylation releases HCMV from latency in monocytes.

Bottom Line: Here, we reveal that HCMV latency in human CD34(+) HSC reflects the recruitment on the viral genome of KAP1, a master co-repressor, together with HP1 and the SETDB1 histone methyltransferase, which results in transcriptional silencing.Correspondingly, HCMV can be forced out of latency by KAP1 knockdown or pharmacological induction of KAP1 phosphorylation, and this process can be potentiated by activating NFkB with TNF-α.These results suggest new approaches both to curtail CMV infection and to purge the virus from organ transplants.

View Article: PubMed Central - PubMed

Affiliation: School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.

ABSTRACT
Human cytomegalovirus (HCMV) is a highly prevalent pathogen that induces life-long infections notably through the establishment of latency in hematopoietic stem cells (HSC). Bouts of reactivation are normally controlled by the immune system, but can be fatal in immuno-compromised individuals such as organ transplant recipients. Here, we reveal that HCMV latency in human CD34(+) HSC reflects the recruitment on the viral genome of KAP1, a master co-repressor, together with HP1 and the SETDB1 histone methyltransferase, which results in transcriptional silencing. During lytic infection, KAP1 is still associated with the viral genome, but its heterochromatin-inducing activity is suppressed by mTOR-mediated phosphorylation. Correspondingly, HCMV can be forced out of latency by KAP1 knockdown or pharmacological induction of KAP1 phosphorylation, and this process can be potentiated by activating NFkB with TNF-α. These results suggest new approaches both to curtail CMV infection and to purge the virus from organ transplants.

Show MeSH
Related in: MedlinePlus