Bmi1 regulate tooth and mandible development by inhibiting p16 signal pathway.

To determine whether the deletion of p16 can correct tooth and mandible growth retardation caused by Bmi1 deficiency, we compared the tooth and mandible phenotypes of homozygous p16-deficient (p16 ) mice, homozygous Bmi1-deficient (Bmi1 ) mice, double homozygous Bmi1 and p16-deficient (Bmi1 p16 ) mice to those of their wild-type littermates at 4 weeks of age by radiograph, histochemistry and immunohistochemistry. Results showed that compared to Bmi1 mice, the dental mineral density, dental volume and dentin sialoprotein immunopositive areas were increased, whereas the ratio of the predentin area to total dentin area and that of biglycan immunopositive area to dentin area were decreased in Bmi1 p16 mice. These results indicate that the deletion of p16 can improve tooth development in Bmi1 knockout mice.

TGF-β1/IL-11/MEK/ERK signaling mediates senescence-associated pulmonary fibrosis in a stress-induced premature senescence model of Bmi-1 deficiency.

To study whether TGF-β1/IL-11/MEK/ERK (TIME) signaling mediates senescence-associated pulmonary fibrosis (SAPF) in Bmi-1-deficient (Bmi-1) mice and determines the major downstream mediator of Bmi-1 and crosstalk between p16 and reactive oxygen species that regulates SAPF, phenotypes were compared among 7-week-old p16 and Bmi-1 double-knockout, N-acetylcysteine (NAC)-treated Bmi-1, Bmi-1, and wild-type mice. Pulmonary fibroblasts and alveolar type II epithelial (AT2) cells were used for experiments. Human pulmonary tissues were tested for type Ι collagen, α-smooth muscle actin (α-SMA), p16, p53, p21, and TIME signaling by using enzyme-linked immunosorbent assay (ELISA).

P16 Deletion Ameliorated Renal Tubulointerstitial Injury in a Stress-induced Premature Senescence Model of Bmi-1 Deficiency.

To determine whether p16 deletion ameliorated renal tubulointerstitial injury by inhibiting a senescence-associated secretory phenotype (SASP) in Bmi-1-deficient (Bmi-1 ) mice, renal phenotypes were compared among 5-week-old Bmi-1 and p16 double-knockout, and Bmi-1 and wild-type mice. Fifth-passage renal interstitial fibroblasts (RIFs) from the three groups were analyzed for senescence and proliferation. The effect of Bmi-1 deficiency on epithelial-to-mesenchymal transition (EMT) was examined in Bmi-1-knockdown human renal proximal tubular epithelial (HK2) cells, which were treated with concentrated conditioned medium (CM) from the fifth-passage renal interstitial fibroblasts (RIFs) of above three group mice or with exogenous TGF-β1.

Bmi-1 plays a critical role in the protection from acute tubular necrosis by mobilizing renal stem/progenitor cells.

The regeneration of injured tubular cell occurs primarily from intrinsic renal stem/progenitor cells (RSCs) labeled with CD24 and CD133 after acute tubular necrosis (ATN). Bmi-1 plays a crucial role in regulating self-renewal, differentiation and aging of multiple adult stem cells and progenitor cells. Bmi-1 was rapidly elevated in the induction of adult kidney regeneration by renal injury.

1, 25-dihydroxy-vitamin D3 with tumor necrosis factor-alpha protects against rheumatoid arthritis by promoting p53 acetylation-mediated apoptosis via Sirt1 in synoviocytes.

Impaired apoptosis of fibroblast-like synoviocytes (FLSs) causes synovial hyperplasia, facilitating destruction of cartilage and bone in rheumatoid arthritis (RA). Tumor necrosis factor (TNF)-α, a dominant inflammatory mediator in RA pathogenesis, promotes progression of RA symptoms. Prevalence of 1, 25-dihydroxy-vitamin D (hereafter termed VD) deficiency is 30-63% in patients with RA.

Anti-aging Effect of Transplanted Amniotic Membrane Mesenchymal Stem Cells in a Premature Aging Model of Bmi-1 Deficiency.

To determine whether transplanted amniotic membrane mesenchymal stem cells (AMSCs) ameliorated the premature senescent phenotype of Bmi-1-deficient mice, postnatal 2-day-old Bmi-1(-/-) mice were injected intraperitoneally with the second-passage AMSCs from amniotic membranes of β-galactosidase (β-gal) transgenic mice or wild-type (WT) mice labeled with DiI. Three reinjections were given, once every seven days. Phenotypes of 5-week-old β-gal(+) AMSC-transplanted or 6-week-old DiI(+) AMSC-transplanted Bmi-1(-/-) mice were compared with vehicle-transplanted Bmi-1(-/-) and WT mice.

Bmi-1 plays a critical role in protection from renal tubulointerstitial injury by maintaining redox balance.

To determine whether Bmi-1 deficiency could lead to renal tubulointerstitial injury by mitochondrial dysfunction and increased oxidative stress in the kidney, 3-week-old Bmi-1(-/-) mice were treated with the antioxidant N-acetylcysteine (NAC, 1 mg mL(-1) ) in their drinking water, or pyrro-quinoline quinone (PQQ, 4 mg kg(-1) diet) in their diet for 2 weeks, and their renal phenotypes were compared with vehicle-treated Bmi1(-/-) and wild-type mice. Bmi-1 was knocked down in human renal proximal tubular epithelial (HK2) cells which were treated with 1 mm NAC for 72 or 96 h, and their phenotypes were compared with control cells. Five-week-old vehicle-treated Bmi-1(-/-) mice displayed renal interstitial fibrosis, tubular atrophy, and severe renal function impairment with decreased renal cell proliferation, increased renal cell apoptosis and senescence, and inflammatory cell infiltration.