In primary murine osteoblasts, 2.5 μM baricitinib reduced induced RANKL mRNA without changing M-CSF or OPG mRNA after 24 hours. A parallel 24-hour assay found no significant viability reduction at 0.01–10 μM, but viability was reduced at 50 μM. This short viability control does not establish tolerability during longer co-culture exposure. [1]
Osteoblast-supported osteoclast differentiation and rescue
Cell-based study · Primary murine calvaria-derived osteoblasts co-cultured with bone marrow cells [1]
Baricitinib reduced stimulated TRAP-positive multinucleated osteoclast formation. Added RANKL rescued this response, whereas added M-CSF did not.
Literature-Reported Treatment Conditions
- Treatment concentration
- 0.1, 1, 2.5 and 5 μM (Figure 1B); 2.5 μM in rescue experiment
- Exposure duration
- 6–7 d
- Method
- Added to co-cultures
- Vehicle
- Vehicle control; DMSO identified elsewhere in the same paper for osteoblast assays, but differentiation vehicle composition not separately stated.
- Co-treatment
- 10−8 M 1,25D3 plus 10−6 M PGE2; rescue arms additionally contained RANKL or M-CSF.
- Reported limits
- Exact differentiation vehicle concentration, baricitinib lot, salt and purity not stated in the selected methods.
Methods and source locations
Compound reported in the paper: Baricitinib; Compound label in the paper: Baricitinib
Evidence applies to the named compound in the reported model; it does not establish identity or performance of the current A11329 lot.
Methods: In vitro osteoclast differentiation assay; Results paragraphs 1–2; Figure 1A–B and Figure 2C–D
TRAP-positive multinuclear osteoclasts per well (>3 nuclei): TRAP staining and multinuclear cell counting; stimulated vehicle and unstimulated vehicle comparators. — Figure 1A–B; caption; Results paragraph 1
Rescue of osteoclast formation at 2.5 μM baricitinib: Same co-culture differentiation endpoint with added recombinant RANKL or M-CSF. — Figure 2C–D; caption; Results paragraph 2
Direct RANKL-driven differentiation: negative response
Cell-based study · Murine bone marrow macrophages cultured with M-CSF and GST-RANKL [1]
Baricitinib did not inhibit RANKL-induced osteoclast differentiation; large osteoclasts were observed. This limits a general claim of direct precursor inhibition.
Literature-Reported Treatment Conditions
- Treatment concentration
- 0.1, 1, 2.5 and 5 μM
- Exposure duration
- 3–4 d after macrophage preparation
- Method
- Added to macrophage cultures
- Vehicle
- Vehicle comparator; exact composition not separately specified in differentiation methods.
- Co-treatment
- 50 ng ml−1 M-CSF plus 200 ng ml−1 GST-RANKL
- Reported limits
- The paper does not give an equivalence margin; lack of inhibition is not proof of identical responses. Exact vehicle concentration and lot/form not established.
Methods and source locations
Compound reported in the paper: Baricitinib; Compound label in the paper: Baricitinib
Evidence applies to the named compound in the reported model; it does not establish identity or performance of the current A11329 lot.
Methods: In vitro osteoclast differentiation assay; Results paragraph 1; Figure 1C–D
RANKL-induced TRAP-positive multinuclear cells per well: TRAP staining/counting; M-CSF present, with RANKL-negative and RANKL-positive vehicle comparators. — Figure 1C–D; caption; Results paragraph 1
Osteoblast RANKL expression with a viability control
Cell-based study · Primary murine calvaria-derived osteoblasts [1]
At 2.5 μM, baricitinib suppressed stimulus-induced RANKL mRNA without altering M-CSF or OPG mRNA. The 24-hour viability assay showed no significant loss at 0.01–10 μM but reduced viability at 50 μM.
Literature-Reported Treatment Conditions
- Treatment concentration
- 2.5 μM for gene expression; 0.01, 0.1, 1, 2.5, 10 and 50 μM for viability
- Exposure duration
- 24 h
- Method
- Added to osteoblast cultures
- Vehicle
- DMSO
- Co-treatment
- 10−8 M 1,25D3 plus 10−6 M PGE2 for stimulated expression arms.
- Reported limits
- Exact DMSO concentration and biological versus technical interpretation of caption n are not specified. Short viability assay does not establish viability throughout the longer differentiation assays.
Methods and source locations
Compound reported in the paper: Baricitinib; Compound label in the paper: Baricitinib
Evidence applies to the named compound in the reported model; it does not establish identity or performance of the current A11329 lot.
Methods: Cell viability assay and qPCR assay; Results paragraph 2; Figure 2A–B
RANKL, M-CSF and OPG transcript abundance relative to β-actin: qPCR after 24 h; unstimulated and stimulated DMSO controls. — Figure 2B; caption; Results paragraph 2
24-hour osteoblast viability relative to DMSO vehicle: Cell Counting Kit-8; vehicle set to 100%; Dunnett multiple comparisons. — Figure 2A; caption; Results paragraph 2
