PhD Scientific Days 2026

Poster Session 3.U - Molecular Medicine

Genetically Modified HoxB8 Progenitor Cells for Functional Analysis of Osteoclastogenesis

Name of the presenter

Markó, Dorottya

Institute/workplace of the presenter

Department of Physiology, Semmelweis University

Authors

Dorottya Markó¹, Áron Pánczél¹, Attila Mócsai²
1: Department of Physiology, Semmelweis University
2: 1Department of Physiology, Semmelweis University

Text of the abstract

Background: Osteoclasts are multinuclear giant cells originating from the myeloid
lineage of the hematopoietic system. As the only cell type capable of bone resorption,
they play a central role in maintaining skeletal homeostasis. Impaired osteoclast
formation or function causes osteopetrosis, whereas excessive bone resorptive activity
occurs during osteoporosis, inflammatory bone erosion, and osteolytic bone
metastases. Due to their role in physiological and pathological bone metabolism,
understanding the molecular and cellular mechanisms that control osteoclast biology
remains a significant research priority.

Methods: Our research group has previously established a HoxB8-based system in
which mouse bone marrow cells were retrovirally transduced with ER-HoxB8 fusion
protein. In the presence of β-estradiol, the HoxB8 is activated, resulting in the generation
of conditionally immortalized HoxB8 progenitor cells. Upon β-estradiol withdrawal,
these progenitors can be differentiated toward multiple myeloid cell types.

Aims: Our aim is to develop a HoxB8 cell line that can be differentiated toward
osteoclast-like cells and to apply the lentiviral CRISPR/Cas9 system for targeted gene
deletions in these progenitors.

Results: Upon stimulation with M-CSF and RANKL for six days, the HoxB8 progenitors
differentiated toward multinucleated, TRAP-positive cells, confirming the
osteoclastogenic potential of the system. We are currently performing CRISPR/Cas9-
based gene editing to generate HoxB8 cell lines that lack RANK or DC-STAMP,
supposedly leading to defective differentiation into osteoclasts and fusion into
multinucleated cells, respectively.

Conclusion: Our results demonstrate that the HoxB8 system is an efficient method for
functional studies of osteoclast differentiation and activity.