Site-1 protease ablation in the osterix-lineage in mice results in bone marrow neutrophilia and hematopoietic stem cell alterations

Abstract

Site-1 protease (S1P) ablation in the osterix-lineage in mice drastically reduces bone development and downregulates bone marrow-derived skeletal stem cells. Here we show that these mice also suffer from spina bifida occulta with a characteristic lack of bone fusion in the posterior neural arches. Molecular analysis of bone marrow-derived non-red blood cell cells, via single-cell RNA-Seq and protein mass spectrometry, demonstrate that these mice have a much-altered bone marrow with a significant increase in neutrophils and Ly6C-expressing leukocytes. The molecular composition of bone marrow neutrophils is also different as they express more and additional members of the stefin A (Stfa) family of proteins. In vitro, recombinant Stfa1 and Stfa2 proteins have the ability to drastically inhibit osteogenic differentiation of bone marrow stromal cells, with no effect on adipogenic differentiation. FACS analysis of hematopoietic stem cells show that despite a decrease in hematopoietic stem cells, S1P ablation results in an increased production of granulocyte-macrophage progenitors, the precursors to neutrophils. These observations indicate that S1P has a role in the lineage specification of hematopoietic stem cells and/or their progenitors for development of a normal hematopoietic niche. Our study designates a fundamental requirement of S1P for maintaining a balanced regenerative capacity of the bone marrow niche.

Differential Gene Expression Involved in Bone Turnover of Mice Expressing Constitutively Active TGFβ Receptor Type I

“…The results of qPCR analysis showed that 9 upregulated genes, Pdzk1 , Vpreb1a , Cd72 , Igll1 , Tnfrsf19 , Gas6 , Zdhhc2 , Igfbp4 , and Hdac7, were significantly increased, and 10 downregulated genes, Dhcr24 , Padi4 , Gsr , Clec4d , Lilrb4a , Clec4e , Fcgr4 , Stfa2 , Olfm4 , and Cxcr1, were significantly decreased in Mx1;TβRI CA compared to the WT group ( Figure 4 A,B). The functions of these 19 DEGs are briefly described in Supplementary Tables S1 and S2 [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

L2Δ13, a splicing isoform of lysyl oxidase-like 2, causes adipose tissue loss via the gut microbiota and lipid metabolism

“…At least six mouse tissues per group were used for the experiment. (Patra et al, 2020). Cells were incubated at 37 C under normoxic conditions and the medium was changed every 3 days until the cells had matured to form adipocytes (Day 8).…”