# Cytoskeletal Mechanisms of Platelet Formation

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2021 · $760,905

## Abstract

Blood platelets are specialized anucleate cells that play an essential role in hemostasis, angiogenesis, wound
healing, immunity, and inflammation. Abnormal platelet counts result in clinical complications and medical
conditions that increasingly require expensive transfusions. As the demand for platelet transfusions rises, the
need for an improved understanding of their mechanistic formation has urgently increased. Our investigations
will target megakaryocytes (MKs), the precursor cells that generate platelets by remodeling their cytoplasm into
beaded proplatelet processes which function as the assembly lines for platelet production. We know that
cytoskeletal mechanics power platelet production, but many questions about platelet biogenesis
remain unanswered. While microtubule-based forces are critical for proplatelet elongation, there is a
surprising lack of understanding of the mechanisms that trigger MKs to undergo the cytoskeletal
rearrangements needed to initiate proplatelet production. Aim 1 will test a new hypothesis that centrosome
clustering and subsequent monospindle formation cause mature MKs to initiate proplatelet formation. We will
interrogate the role of the molecular motor KIFC1 in centrosome clustering and proplatelet induction. Although
the mechanism by which sliding of cortical microtubules powers proplatelet extension is unknown, our recent
observation that inhibition of the actin assembly process paralyzes proplatelet elongation suggests a role for
actin. This exciting new data indicates that actin may function as a molecular clutch and promote microtubule
sliding and/or anchoring of microtubules to the membrane, which will be tested in Aim 2. Finally, we know that
proplatelet protrusions extend from bone marrow, breach the endothelial barrier, and deposit platelets into the
blood, but we do not know how. Aim 3 will employ an engineered, endothelialized, microfluidic bone marrow
on-a-chip to test the idea that actin-driven megakaryocyte podosomes provide a mechanism to penetrate the
endothelium. Biologically inspired engineering will be used to study how podosomes transition to proplatelet
production and to test the role of monospindle formation in proplatelet polarization into the bloodstream. We
expect that findings from this investigation will 1) improve the understanding of the molecular mechanisms that
regulate platelet formation in health and disease, 2) lay the foundation for novel therapeutic approaches to
accelerate platelet production in patients with thrombocytopenia, and 3) enable the future creation of in vitro
platelets.

## Key facts

- **NIH application ID:** 10209279
- **Project number:** 2R01HL068130-20
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** JOSEPH E ITALIANO
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $760,905
- **Award type:** 2
- **Project period:** 2001-07-01 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10209279

## Citation

> US National Institutes of Health, RePORTER application 10209279, Cytoskeletal Mechanisms of Platelet Formation (2R01HL068130-20). Retrieved via AI Analytics 2026-07-16 from https://api.ai-analytics.org/grant/nih/10209279. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*