Identification of the active components in Bone Marrow Soup: a mitigator against irradiation-injury to salivary glands

Abstract

In separate studies, an extract of soluble intracellular contents from whole bone marrow cells, named “Bone Marrow (BM) Soup”, was reported to either improve cardiac or salivary functions post-myocardial infarction or irradiation (IR), respectively. However, the active components in BM Soup are unknown. To demonstrate that proteins were the active ingredients, we devised a method using proteinase K followed by heating to deactivate proteins and for safe injections into mice. BM Soup and “deactivated BM Soup” were injected into mice that had their salivary glands injured with 15Gy IR. Control mice received either injections of saline or were not IR. Results at week 8 post-IR showed the ‘deactivated BM Soup’ was no better than injections of saline, while injections of native BM Soup restored saliva flow, protected salivary cells and blood vessels from IR-damage. Protein arrays detected several angiogenesis-related factors (CD26, FGF, HGF, MMP-8, MMP-9, OPN, PF4, SDF-1) and cytokines (IL-1ra, IL-16) in BM Soup. In conclusion, the native proteins (but not the nucleic acids, lipids or carbohydrates) were the therapeutic ingredients in BM Soup for functional salivary restoration following IR. This molecular therapy approach has clinical potential because it is theoretically less tumorigenic and immunogenic than cell therapies.

Lyophilized bone marrow cell extract functionally restores irradiation‐injured salivary glands

“…All the procedures followed the manufacturer's instructions and were described previously in Fang et al. ().…”

“…100 μl of normal saline, BMCE or FD‐BMCE was injected through the tail vein at 5–7 days post‐IR, twice a week for two consecutive weeks, as described in Fang et al. (). Mice were sacrificed after 8 and 16 weeks post‐IR.…”

“…Salivary flow rate (SFR) and lag time measurements were taken at week 4, 8, 12, and 16 post‐IR, as described in Fang et al. (). Histological analyses, such as hematoxylin/eosin and PCNA, immunofluorescent staining using aquaporin 5 (to detect acinar cells), smooth muscle actin (myoepithelial cells), cytokeratin 5 (basal ductal cells and a subpopulation of myoepithelial cells), GFRα‐2 (parasympathetic nerves), CD31 (endothelial cells), and quantitative real‐time PCR (qRT‐PCR) for EGF, VEGF, IGF‐1R, HGF, FGF2, GFRα2, AQP5, CK5, and GAPDH were performed as previously described in Fang et al.…”

Bone marrow cell extract promotes the regeneration of irradiated bone

“…It may be an action of SDF-1 and IL-1ra, found in BMCE [28]. SDF-1 is a factor inducing stem cells to migrate from the bone marrow to the damage site [34].…”

Three‐Dimensional Bioprinting Nanotechnologies towards Clinical Application of Stem Cells and Their Secretome in Salivary Gland Regeneration

“…Earlier studies in mouse irradiated SG had similar functional outcomes, when BM-derived cells were mobilized by G-CSF/FLT3/SCF [50, 62]. The clinical translation of these cellular paracrine effects led investigators to identify such bioactive secretome components secreted by BM-derived cells [15, 16]. Protein microarrays detected several angiogenesis-related factors (CD26, FGF1, HGF, MMP-8, MMP-9, OPN, PF4, and SDF-1) and cytokines (IL-1ra, IL-16) in the BM secretome (Table 3) [16]; thereby, several signaling pathways may be involved and the contribution of each secretome component towards epithelial repair and SG regeneration requires further investigation.…”