Diabetologie und Stoffwechsel 2018; 13(S 01): S59-S60
DOI: 10.1055/s-0038-1641934
Poster
Typ-1-Diabetes II
Georg Thieme Verlag KG Stuttgart · New York

CVB5 proteases 2A targets insulin granule biogenesis in MIN6 cells

KP Knoch
1   TU Dresden, Medizinische Fakultät, Paul Langerhans Institut Dresden, Molecular Diabetology, Dresden, Germany
2   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany, Neuherberg, Germany
,
A Petzold
1   TU Dresden, Medizinische Fakultät, Paul Langerhans Institut Dresden, Molecular Diabetology, Dresden, Germany
2   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany, Neuherberg, Germany
,
C Wegbrod
1   TU Dresden, Medizinische Fakultät, Paul Langerhans Institut Dresden, Molecular Diabetology, Dresden, Germany
2   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany, Neuherberg, Germany
,
A Sönmez
1   TU Dresden, Medizinische Fakultät, Paul Langerhans Institut Dresden, Molecular Diabetology, Dresden, Germany
2   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany, Neuherberg, Germany
,
C Münster
1   TU Dresden, Medizinische Fakultät, Paul Langerhans Institut Dresden, Molecular Diabetology, Dresden, Germany
2   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany, Neuherberg, Germany
,
A Friedrich
1   TU Dresden, Medizinische Fakultät, Paul Langerhans Institut Dresden, Molecular Diabetology, Dresden, Germany
2   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany, Neuherberg, Germany
,
Z Marinicova
1   TU Dresden, Medizinische Fakultät, Paul Langerhans Institut Dresden, Molecular Diabetology, Dresden, Germany
2   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany, Neuherberg, Germany
,
J Merl-Pham
3   Research Unit Protein Science Helmholtz Center Munich, Munich, Germany
,
S Hauck
3   Research Unit Protein Science Helmholtz Center Munich, Munich, Germany
,
M Solimena
1   TU Dresden, Medizinische Fakultät, Paul Langerhans Institut Dresden, Molecular Diabetology, Dresden, Germany
2   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany, Neuherberg, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
26 April 2018 (online)

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    Background and aims:

    Coxsackieviruses B (CVBs) are among the candidate environmental factors implicated in the pathogenesis of type 1 diabetes. Their cap-independent translation in β-cells relies on factors that are also implicated in the translation of insulin granule components (Knoch et al, 2014). Notably, CVB Infection of β-cells strongly reduces their insulin granule stores and release. Therefore, we are interested in elucidating how CVB proteases affect the traffic and stability of insulin granule cargoes.

    Materials and methods:

    MIN6 cells were transfected with either CVB5 protease 2A or 3C or infected with CVB5. Levels of insulin and other granule cargoes in control and CVB expressing cells were assessed by western blotting, ELISA, immunostaining and quantitative proteomics.

    Results:

    The levels of insulin and other granule markers were unaffected in MIN6 cells expressing CVB5 3C, while they were reduced in cells infected with CVB5 or transfected with CVB5 2A. Granule cargo depletion in CVB5 and CVB 2A expressing cells neither correlated with ER stress nor apoptosis. Proteomic analysis revealed instead the reduced levels of several factors involved in post-Golgi vesicular transport, such as Arf1, GGA2, Rab3b and Sytl4. However, only the knockdown of Rab3b and GGA2 resulted in a phenotype similar to the one observed upon overexpression of CVB5 2A.

    Conclusions:

    We propose that CVB 2A blocks insulin granule biogenesis from the Golgi complex. The depletion of newly-generated granules likely accounts for the reduction of insulin secretion in CVB-infected β-cells, while massive degradation of granule cargoes may affect their antigenic presentation.


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