Biology subjects

Guilz, N. C.

Publications and source records attributed to Guilz, N. C..

3 recordsLinked to original sources

bioRxiv2023

iPSC-based modeling of helicase deficiency reveals impaired cell proliferation and increased apoptosis after NK cell lineage commitment

While monogenic variants in CDC45-MCM-GINS (CMG) replisome proteins cause human natural killer cell deficiencies (NKD), family members with the same inherited variants often have variable clinical and cellular phenotypes. We investigated two siblings with inherited compound heterozygous GINS4 variants but variable disease expressivity. Cell cycle impairment and increased apoptosis were detected following NK cell lineage commitment but not in pluripotent cells. While this effect was detected in both siblings, the efficiency of NK cell differentiation was variable and correlated with differential clinical severity of NKD. Further investigation of allelic expression of inherited GINS4 variants demonstrated expected biallelic expression of GINS4 in pluripotent cells and progenitors. However, allelic bias in lineage-committed NK cells led to over- or under-representation of more damaging GINS4 heterozygous variants associated with differential cellular and clinical severity. This study identifies allelic bias that causes phenotypic variation of monogenic diseases and defines mechanisms underlying immunodeficiency.

cell biology↗

bioRxiv2023

Replication stress in activated human NK cells induces sensitivity to apoptosis

Natural killer cells are innate immune effectors that kill virally infected or malignant cells. Natural killer cell deficiency (NKD) occurs when NK cell development or function are impaired, and individuals with NKD are susceptible to severe and recurrent viral infections. Several gene deficiencies result in NKD, including variants in MCM4, GINS1, MCM10 and GINS4, which are components of the CDC45-MCM-GINS (CMG) helicase. The CMG helicase unwinds DNA during replication and is expressed in any actively proliferating cell. NK cells are more strongly impacted by mutational deficiencies in helicase proteins than other lymphocytes, though the mechanisms underlying this susceptibility are not completely understood. NK cells from individuals with NKD as a result of helicase deficiency have increased DNA damage, cell cycle arrest, and replication stress. Here, we induced replication stress in activated mature NK cells or T cells by chemical methods, using aphidicolin, and through shRNA knockdown of MCM10 in an NK cell line. We found that the CD56bright subset of NK cells accumulates more DNA damage and replication stress during activation than CD56dim NK cells or activated T cells. Aphidicolin treatment increases apoptosis of CD56bright NK cells through increased pan-caspase expression and decreases perforin expression in surviving cells. This effect is modeled by shRNA mediated knockdown of MCM10, thus linking decreased helicase protein expression to replication stress and impaired NK cell function. These findings show that sensitivity to replication stress affects human NK cell survival and function and can contribute to NK cell deficiency.

immunology↗

bioRxiv2020

Bile acid composition regulates the manganese transporter Slc30a10 in intestine

Bile acids (BAs) comprise heterogenous amphipathic cholesterol-derived molecules that carry out physicochemical and signaling functions. A major site of BA action is the terminal ileum, where enterocytes actively reuptake BAs and express high levels of BA-sensitive nuclear receptors. BA pool size and composition are affected by changes in metabolic health, and vice versa. One of several factors that differentiate BAs is the presence of a hydroxyl group on C12 of the steroid ring. 12a-hydroxylated BAs (12HBAs) are altered in multiple disease settings, but the consequences of 12HBA abundance are incompletely understood. We employed mouse primary ileum organoids to investigate the transcriptional effects of varying 12HBA abundance in BA pools. We identified Slc30a10 as one of the top genes differentially induced by BA pools with varying 12HBA abundance. SLC30A10 is a manganese (Mn) efflux transporter critical for whole-body manganese excretion. We found that BA pools, especially those low in 12HBAs, induce cellular manganese efflux, and that Slc30a10 induction by BA pools is driven primarily by lithocholic acid signaling via the vitamin D receptor. Administration of lithocholic acid or a vitamin D receptor agonist resulted in increased Slc30a10 expression in mouse ileum epithelia. These data demonstrate a previously unknown role for BAs in intestinal control of Mn homeostasis.

cell biology↗