Wiskott-Aldrich syndrome protein senses irradiation-induced DNA damage to coordinate the cell-protective Golgi dispersal response in human T and B lymphocytes

Abstract

Background: Wiskott-Aldrich syndrome (WAS) is an X-linked primary immune deficiency disorder resulting from Wiskott-Aldrich syndrome protein (WASp) deficiency. Lymphocytes from patients with WAS manifest increased DNA damage and lymphopenia from cell death, yet how WASp influences DNA damage-linked cell survival is unknown. A recently described mechanism promoting cell survival after ionizing radiation (IR)-induced DNA damage involves fragmentation and dispersal of the Golgi apparatus, known as the Golgi-dispersal response (GDR), which uses the Golgi phosphoprotein 3 (GOLPH3)-DNA-dependent protein kinase (DNA-PK)-myosin XVIIIA-F-actin signaling pathway. Objective: We sought to define WASp's role in the DNA damage-induced GDR and its disruption as a contributor to the development of radiosensitivity-linked immunodeficiency in patients with WAS. Methods: In human T H and B-cell culture systems, DNA damage-induced GDR elicited by IR or radiomimetic chemotherapy was monitored in the presence or absence of WASp or GOLPH3 alone or both together. Results: WASp deficiency completely prevents the development of IR-induced GDR in human T H and B cells, despite the high DNA damage load. Loss of WASp impedes nuclear translocation of GOLPH3 and its colocalization with the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Surprisingly, however, depletion of GOLPH3 alone or depolymerization of F-actin in WASp-sufficient T H cells still allows development of robust GDR, suggesting that WASp, but not GOLPH3, is essential for GDR and cell survival after IR-induced DNA-damage in human lymphocytes. Conclusion: The study identifies WASp as a novel effector of the nucleus-to-Golgi cell-survival pathway triggered by IR-induced DNA damage in cells of the hematolymphoid lineage and proposes an impaired GDR as a new cause for development of a ''radiosensitive'' form of immune dysregulation in patients with WAS.

Reversion Mosaicism in Primary Immunodeficiency Diseases

“…(Table 3). Loss-of-function mutations in genes that are involved in genomic stability such as BLM, LIG4, FANCA, FANCC, FANCD2, and presumably WAS may be associated with a high incidence of reversion mutations (3,(51)(52)(53). Gene variation analysis, used to evaluate the mutation frequency of PID genes in which reversion events have or have not been described, has revealed that genetic variation is significantly greater for revertant genes than for nonrevertant or control genes, especially in coding sequences (18).…”

“…It also has an important role in correcting existing double strand breaks in human B-cells ( 52 ). Moreover, another study revealed a novel function of WASp in the DNA-damage-induced Golgi dispersal response, and its disruption as a contributor to radiosensitivity in T- and B-cells ( 53 ). WASp accordingly has critical functions in maintaining a stable genome in human T- and B-cells.…”

Actin Remodeling Defects Leading to Autoinflammation and Immune Dysregulation

“…WASP deficiency promotes T-cell cytoskeletal tension decay and phosphorylation of a serine/threonine protein kinase 4 (STK4) that usually increase T-cell migration, therefore promoting immune synapse breaking and secondary B cells dysfunction ( 93 , 94 ). WASP-deficient lymphocytes fails to differentiate into memory cells ( 95 ) and are more prone to develop DNA damages due to the loss of the Golgi-dispersal response, a recently described mechanism of cell survival after ionized radiation exsposure ( 96 ). The STK4 deficiency causes a PID characterized by B and T cell lymphopenia, neutropenia, and cardiac malformations (no.…”

Constitutive activation of WASp leads to abnormal cytotoxic cells with increased granzyme B and degranulation response to target cells

“…WAS patients are prone to developing malignancies of poor prognosis and most frequently lymphoreticular tumors including non-Hodgkin lymphoma (76% of the total tumors associated with WAS), Hodgkin lymphoma, and Burkitt lymphoma ( 46 – 50 ). Both reduced tumor immunosurveillance by cytotoxic cells ( 15 , 30 – 34 , 37 – 39 ) and intrinsic cell transformation ( 15 , 51 , 52 ) contribute to malignancies in WAS. In the family with WASp L270P XLN ( 1 ), 2 out of 6 affected males have developed myelodysplastic syndrome and leukemia, and 1 unrelated patient with the WASp I294T mutation developed myelodysplastic syndrome ( 2 ).…”