TFG is required for autophagy flux and to prevent endoplasmic reticulum stress in CH12 B lymphoma cells
| Autor: | Wolfgang Schuh, Thomas Winkler, Tobit Steinmetz, Ursula Schlötzer-Schrehardt, Dirk Mielenz, Abigail Hearne, Jens Wittner, Sebastian R. Schulz, Hans-Martin Jäck |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Lymphoma
B-Cell B-cell receptor Biology Endoplasmic-reticulum-associated protein degradation Plasma cell Endoplasmic Reticulum Mice chemistry.chemical_compound Cell Line Tumor Autophagy medicine Animals Molecular Biology B cell Secretory pathway Adaptor Proteins Signal Transducing Endoplasmic reticulum Autophagosomes Proteins Cell Biology Tunicamycin Endoplasmic Reticulum Stress Cell biology medicine.anatomical_structure chemistry Unfolded protein response Research Paper |
| Zdroj: | Autophagy |
| DOI: | 10.6084/m9.figshare.12939607 |
| Popis: | Plasma cells depend on quality control of newly synthesized antibodies in the endoplasmic reticulum (ER) via macroautophagy/autophagy and proteasomal degradation. The cytosolic adaptor protein TFG (Trk-fused gene) regulates ER-Golgi transport, the secretory pathway and proteasome activity in non-immune cells. We show here that TFG is upregulated during lipopolysaccharide- and CpG-induced differentiation of B1 and B2 B cells into plasmablasts, with the highest expression of TFG in mature plasma cells. CRISPR-CAS9-mediated gene disruption of tfg in the B lymphoma cell line CH12 revealed increased apoptosis, which was reverted by BCL2 but even more by ectopic TFG expression. Loss of TFG disrupted ER structure, leading to an expanded ER and increased expression of ER stress genes. When compared to wild-type CH12 cells, tfg KO CH12 cells were more sensitive toward ER stress induced by tunicamycin, monensin and proteasome inhibition or by expression of an ER-bound immunoglobulin (Ig) μ heavy (µH) chain. CH12 tfg KO B cells displayed more total LC3, lower LC3-II turnover and increased numbers and size of autophagosomes. Tandem-fluorescent-LC3 revealed less accumulation of GFP-LC3 in starved and chloroquine-treated CH12 tfg KO B cells. The GFP:RFP ratio of tandem-fluorescent-LC3 was higher in tunicamycin-treated CH12 tfg KO B cells, suggesting less autophagy flux during induced ER stress. Based on these data, we suggest that TFG controls autophagy flux in CH12 B cells and propose that TFG is a survival factor that alleviates ER stress through the support of autophagy flux in activated B cells and mature plasma cells.Abbreviations: Ab, antibody; Ag, antigen; ASC, antibody-secreting cells; ATG, autophagy-related; BCR, B cell receptor; COPII, coat protein complex II; CpG, non-methylated CpG oligonucleotide; ER, endoplasmic reticulum; ERAD, ER-associated degradation; FO, follicular; GFP, green fluorescent protein; HC, heavy chain; Ig, immunoglobulin; IRES, internal ribosomal entry site; LC, light chain; MZ, marginal zone; NFKB, nuclear factor of kappa light polypeptide gene enhancer in B cells; TLR, toll-like receptor; UPR, unfolded protein response. |
| Databáze: | OpenAIRE |
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