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DAMP production by human islets under low oxygen and nutrients in the presence or absence of an immunoisolating-capsule and necrostatin-1.

Paredes-Juarez GA, Sahasrabudhe NM, Tjoelker RS, de Haan BJ, Engelse MA, de Koning EJ, Faas MM, de Vos P - Sci Rep (2015)

Bottom Line: Immunoisolation in immunoprotective membranes reduced DAMP release and immune activation via retention of the relative large DAMPs in the capsules.Another effective strategy was suppressing necroptosis using the inhibitor nec-1.DAMP release can be reduced in vitro by immunoisolation or intervention with nec-1.

View Article: PubMed Central - PubMed

Affiliation: University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Section of Immunoendocrinology, Groningen, 9713 GZ, The Netherlands.

ABSTRACT
In between the period of transplantation and revascularization, pancreatic islets are exposed to low-oxygen and low-nutrient conditions. In the present study we mimicked those conditions in vitro to study the involvement of different cell death processes, release of danger-associated molecular patterns (DAMP), and associated in vitro immune activation. Under low-oxygen and low-nutrient conditions, apoptosis, autophagy and necroptosis occur in human islets. Necroptosis is responsible for DAMP-release such as dsDNA, uric acid, and HMGB1. The sensors of the innate immune system able to recognize these DAMPs are mainly TLR, NOD receptors, and C-type lectins. By using cell-lines with a non-functional adaptor molecule MyD88, we were able to show that the islet-derived DAMPs signal mainly via TLR. Immunoisolation in immunoprotective membranes reduced DAMP release and immune activation via retention of the relative large DAMPs in the capsules. Another effective strategy was suppressing necroptosis using the inhibitor nec-1. Although the effect on cell-survival was minor, nec-1 was able to reduce the release of HMGB1 and its associated immune activation. Our data demonstrate that in the immediate post-transplant period islets release DAMPs that in vitro enhance responses of innate immune cells. DAMP release can be reduced in vitro by immunoisolation or intervention with nec-1.

No MeSH data available.


Related in: MedlinePlus

Comparison of nuclear DNA content between encapsulated islets with or without nec-1.Nuclei of control encapsulated and encapsulated nec-1 human islets were isolated for quantification of DNA before and after incubation for 7 days under control and low nutrients at 20% and 1% of oxygen. Human islets encapsulated in conventional APA system contained statistical significantly lower amounts of DNA after incubation under control and low nutrients at 1% of oxygen (*p < 0.05) when compared with capsules at day 0. Values are presented as median ± IQR (n = 4 separate batches of human islets).
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f6: Comparison of nuclear DNA content between encapsulated islets with or without nec-1.Nuclei of control encapsulated and encapsulated nec-1 human islets were isolated for quantification of DNA before and after incubation for 7 days under control and low nutrients at 20% and 1% of oxygen. Human islets encapsulated in conventional APA system contained statistical significantly lower amounts of DNA after incubation under control and low nutrients at 1% of oxygen (*p < 0.05) when compared with capsules at day 0. Values are presented as median ± IQR (n = 4 separate batches of human islets).

Mentions: Since necroptosis is one of the main cell-death processes responsible for release of DAMPs, we studied the effect of nec-1, a potent inhibitor of necroptosis22, on cell survival after 7 days of culture in the different conditions. At day 0, islets contained 279.54 ± 37.39 ng/ml of nuclear DNA. The DNA content decreased under the different culture conditions, which could partly be prevented by addition of nec-1 to the capsules. This however only reached statistical significance when cultured in 1% of oxygen in the presence or absence of low-nutrient conditions when compared with day 0 (Fig. 6).


DAMP production by human islets under low oxygen and nutrients in the presence or absence of an immunoisolating-capsule and necrostatin-1.

Paredes-Juarez GA, Sahasrabudhe NM, Tjoelker RS, de Haan BJ, Engelse MA, de Koning EJ, Faas MM, de Vos P - Sci Rep (2015)

Comparison of nuclear DNA content between encapsulated islets with or without nec-1.Nuclei of control encapsulated and encapsulated nec-1 human islets were isolated for quantification of DNA before and after incubation for 7 days under control and low nutrients at 20% and 1% of oxygen. Human islets encapsulated in conventional APA system contained statistical significantly lower amounts of DNA after incubation under control and low nutrients at 1% of oxygen (*p < 0.05) when compared with capsules at day 0. Values are presented as median ± IQR (n = 4 separate batches of human islets).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4588515&req=5

f6: Comparison of nuclear DNA content between encapsulated islets with or without nec-1.Nuclei of control encapsulated and encapsulated nec-1 human islets were isolated for quantification of DNA before and after incubation for 7 days under control and low nutrients at 20% and 1% of oxygen. Human islets encapsulated in conventional APA system contained statistical significantly lower amounts of DNA after incubation under control and low nutrients at 1% of oxygen (*p < 0.05) when compared with capsules at day 0. Values are presented as median ± IQR (n = 4 separate batches of human islets).
Mentions: Since necroptosis is one of the main cell-death processes responsible for release of DAMPs, we studied the effect of nec-1, a potent inhibitor of necroptosis22, on cell survival after 7 days of culture in the different conditions. At day 0, islets contained 279.54 ± 37.39 ng/ml of nuclear DNA. The DNA content decreased under the different culture conditions, which could partly be prevented by addition of nec-1 to the capsules. This however only reached statistical significance when cultured in 1% of oxygen in the presence or absence of low-nutrient conditions when compared with day 0 (Fig. 6).

Bottom Line: Immunoisolation in immunoprotective membranes reduced DAMP release and immune activation via retention of the relative large DAMPs in the capsules.Another effective strategy was suppressing necroptosis using the inhibitor nec-1.DAMP release can be reduced in vitro by immunoisolation or intervention with nec-1.

View Article: PubMed Central - PubMed

Affiliation: University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Section of Immunoendocrinology, Groningen, 9713 GZ, The Netherlands.

ABSTRACT
In between the period of transplantation and revascularization, pancreatic islets are exposed to low-oxygen and low-nutrient conditions. In the present study we mimicked those conditions in vitro to study the involvement of different cell death processes, release of danger-associated molecular patterns (DAMP), and associated in vitro immune activation. Under low-oxygen and low-nutrient conditions, apoptosis, autophagy and necroptosis occur in human islets. Necroptosis is responsible for DAMP-release such as dsDNA, uric acid, and HMGB1. The sensors of the innate immune system able to recognize these DAMPs are mainly TLR, NOD receptors, and C-type lectins. By using cell-lines with a non-functional adaptor molecule MyD88, we were able to show that the islet-derived DAMPs signal mainly via TLR. Immunoisolation in immunoprotective membranes reduced DAMP release and immune activation via retention of the relative large DAMPs in the capsules. Another effective strategy was suppressing necroptosis using the inhibitor nec-1. Although the effect on cell-survival was minor, nec-1 was able to reduce the release of HMGB1 and its associated immune activation. Our data demonstrate that in the immediate post-transplant period islets release DAMPs that in vitro enhance responses of innate immune cells. DAMP release can be reduced in vitro by immunoisolation or intervention with nec-1.

No MeSH data available.


Related in: MedlinePlus