Biology subjects

Pedroza, L. A.

Publications and source records attributed to Pedroza, L. A..

3 recordsLinked to original sources

bioRxiv2026

The Histone Methyltransferase KMT2D promotes Natural Killer cell effector molecule release

Natural Killer (NK) cells eliminate virally infected and cancerous cells by secreting cytotoxic granules and pro-inflammatory cytokines. However, the epigenetic mechanisms that coordinate these processes in human NK cells remain poorly understood. We identified two NK deficiency (NKD) patients with mutations in the histone methyltransferase KMT2D that demonstrated impaired cytotoxicity and degranulation. CRISPR-mediated KMT2D deletion or introduction of a patient-specific mutation in healthy human NK cells was sufficient to inhibit effector functions. NK cell-specific KMT2D deletion in mice resulted in defective NK cell degranulation and IFN-{gamma} production, increasing mortality following MCMV infection. KMT2D loss reduced H3K4me1 deposition, associated with decreased levels of RAB3D. RAB3D-deficient human NK cells reduced the release of GZMB and IFN-{gamma}, without impacting intracellular levels. Thus, KMT2D acts as a conserved epigenetic regulator of mature NK cell functions, promoting rapid effector molecule release.

immunology↗

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↗

bioRxiv2021

Delineating the molecular and phenotypic spectrum of the SETD1B-related syndrome

Pathogenic variants in SETD1B have been associated with a syndromic neurodevelopmental disorder including intellectual disability, language delay and seizures. To date, clinical features have been described for eleven patients with (likely) pathogenic SETD1B sequence variants. We perform an in-depth clinical characterization of a cohort of 36 unpublished individuals with SETD1B sequence variants, describing their molecular and phenotypic spectrum. Selected variants were functionally tested using in vitro and genome-wide methylation assays. Our data present evidence for a loss-of-function mechanism of SETD1B variants, resulting in a core clinical phenotype of global developmental delay, language delay including regression, intellectual disability, autism and other behavioral issues, and variable epilepsy phenotypes. Developmental delay appeared to precede seizure onset, suggesting SETD1B dysfunction impacts physiological neurodevelopment even in the absence of epileptic activity. Interestingly, males are significantly overrepresented and more severely affected, and we speculate that sex-linked traits could affect susceptibility to penetrance and the clinical spectrum of SETD1B variants. Finally, despite the possibility of non-redundant contributions of SETD1B and its paralogue SETD1A to epigenetic control, the clinical phenotypes of the related disorders share many similarities, indicating that elucidating shared and divergent downstream targets of both genes will help to understand the mechanism leading to the neurobehavioral phenotypes. Insights from this extensive cohort will facilitate the counseling regarding the molecular and phenotypic landscape of newly diagnosed patients with the SETD1B-related syndrome.

genetics↗