# Novel Pathways in Ischemic Stroke in Sickle Cell Anemia

> **NIH NIH R01** · BAYLOR COLLEGE OF MEDICINE · 2020 · $527,933

## Abstract

Stroke is a devastating complication of sickle cell anemia (SCA) that will occur in ~11% of all patients without
intervention. In pediatric patients with SCA, most of these strokes are ischemic and strongly linked with arterial
vasculopathy. There is a strong heritable component that affects development of stroke in SCA patients.
However, our understanding of the genes involved is very limited. Our group reported an unbiased genome wide
association study of stroke in SCA using whole exome sequencing. We identified and validated two particular
missense mutations in the GOLGB1 (Y1212C) and ENPP1 (K173Q) genes as being protective against stroke in
SCA. Our study goal is to define the functional role of GOLGB1 and ENPP1 as modulators of vascular endothelial
injury and ischemic stroke risk.
We have previously observed that: a) GOLGB1 levels affect Golgi structure in monocytes and endothelial
cells; b) The GOLGB1 Y1212C variant is associated with more dispersed Golgi in monocytes isolated from SCA
patients; and c) ENPP1 enzymatic activity is higher in SCA patients with the protective K allele of the ENPP1
K173Q variant. From this preliminary data, we hypothesize that 1) GOLGB1 affects Golgi structure, which in turn
regulates secretory output of pro-thrombotic factors such as von Willebrand factor (vWF) that can affect stroke
in SCA; and 2) that ENPP1 affects risk of thrombosis either through endothelial cell signaling or by hydrolysis of
the pro-inflammatory ATP inorganic pyrophosphate (PPi). We plan to test these hypotheses by analyzing the
function of GOLGB1 and ENPP1 in samples from patients with SCA. We will isolate primary monocyte and
endothelial cells from a large cohort of SCA patients receiving care at Texas Children’s Hospital.We will test our
central hypotheses by pursuing three aims: Aim 1: Examine the role of GOLGB1 in the structure and function of
Golgi complexes in sickle cell anemia - We will use high resolution imaging to determine the role of GOLGB1 in
maintaining Golgi structure and protein trafficking in monocyte and endothelial cells from SCA patients; Aim 2:
Determine the effect of ENPP1 activity in sickle cell anemia - We will measure plasma and endothelial activity of
the ENPP1 enzyme.We will also test whether ENPP1 modulates vascular dysfunction in patients with SCA; Aim
3: Determine impact of GOLGB1 and ENPP1 on endothelial activation in a microfluidic arterial model - We will
combine thrombotic protein assays and RNA expression profiling to identify endothelial activation pathways
affected by our candidate genes.
Our proposed studies will characterize the functional impact of our two genes and their genetic variants
in SCA patient samples. This will benefit our understanding of the pathophysiological pathways of stroke and
potentially provide targets for drug therapy to prevent or treat stroke in SCA patients.

## Key facts

- **NIH application ID:** 9986875
- **Project number:** 5R01HL136415-02
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** Jonathan Michael Flanagan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $527,933
- **Award type:** 5
- **Project period:** 2019-08-01 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9986875

## Citation

> US National Institutes of Health, RePORTER application 9986875, Novel Pathways in Ischemic Stroke in Sickle Cell Anemia (5R01HL136415-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9986875. Licensed CC0.

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