Establishment of NOD/SCID mouse model of central nervous system leukemia

A novel pulmonary fibrosis NOD/SCID murine model with natural aging

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is an age-related disease severely affecting life quality with its prevalence rising as the population ages, yet there is still no effective treatment available. Cell therapy has emerged as a promising option for IPF, however, the absence of mature and stable animal models for IPF immunodeficiency hampers preclinical evaluations of human cell therapies, primarily due to rapid immune clearance of administered cells. This study aims to establish a reliable pulmonary fibrosis (PF) model in immunodeficient mice that supports autologous cell therapy and to investigate underlying mechanism.

METHODS

We utilized thirty 5-week-old male NOD/SCID mice, categorizing them into three age groups: 12weeks, 32 weeks and 43 weeks, with 6 mice euthanized randomly from each cohort for lung tissue analysis. We assessed fibrosis using HE staining, Masson's trichrome staining, α-SMA immunohistochemistry and hydroxyproline content measurement. Further, β-galactosidase staining and gene expression analysis of MMP9, TGF-β1, TNF-α, IL-1β, IL-6, IL-8, SOD1, SOD2, NRF2, SIRT1, and SIRT3 were performed. ELISA was employed to quantify protein levels of TNF-α, TGF-β1, and IL-8.

RESULTS

When comparing lung tissues from 32-week-old and 43-week-old mice to those from 12-week-old mice, we noted a marked increase in inflammatory infiltration, fibrosis severity, and hydroxyproline content, alongside elevated expression levels of α-SMA and MMP9. Notably, the degree of fibrosis intensified with age. Additionally, β-galactosidase staining became more pronounced in older mice. Quantitative PCR analyses revealed age-related, increases in the expression of senescence markers (GLB1, P16, P21), and proinflammatory genes (TGF-β1, TNF-α, IL-1β, IL-6, and IL-8). Conversely, the expression of anti-oxidative stress-related genes (SOD1, SOD2, NRF2, SIRT1, and SIRT3) declined, showing statistically significant differences (*P < 0.05, **P < 0.01, ***P < 0.001). ELISA results corroborated these findings, indicating a progressive rise in the protein levels of TGF-β1, TNF-α, and IL-8 as the mice aged.

CONCLUSIONS

The findings suggest that NOD/SCID mice aged 32 weeks and 43 weeks effectively model pulmonary fibrosis in an elderly context, with the disease pathogenesis likely driven by age-associated inflammation and oxidative stress.

Loss of IRF7 accelerates acute myeloid leukemia progression and induces VCAM1-VLA-4 mediated intracerebral invasion

Interferon regulatory factor 7 (IRF7) is widely studied in inflammatory models. Its effects on malignant progression have been documented mainly from the perspective of the microenvironment. However, its role in leukemia has not been established. Here we used MLL-AF9-induced acute myeloid leukemia (AML) mouse models with IRF7 knockout or overexpression and xenograft mouse models to explore the intrinsic effects of IRF7 in AML. AML-IRF7^−/− mice exhibited accelerated disease progression with intracerebral invasion of AML cells. AML-IRF7^−/− cells showed increased proliferation and elevated leukemia stem cell (LSC) levels. Overexpression of IRF7 in AML cells decreased cell proliferation and LSC levels. Furthermore, overexpression of transforming growth-interacting factor 1 (TGIF1) rescued the enhanced proliferation and high LSC levels caused by IRF7 deficiency. Moreover, upregulation of vascular cell adhesion molecule 1 (VCAM1), which correlated with high LSC levels, was detected in AML-IRF7^−/− cells. In addition, blocking VCAM1-very late antigen 4 (VLA-4) axis delayed disease progression and attenuated intracerebral invasion of AML cells. Therefore, our findings uncover the intrinsic effects of IRF7 in AML and provide a potential strategy to control central nervous system myeloid leukemia.

Experiment research of focused ultrasound combined with drug and microbubble for treatment of central nervous system leukemia

It has been shown that low frequency ultrasound in the presence of microbubble can effectively open the blood brain barrier (BBB) to allow the drugs to be delivered into the brain with an increased concentration. We aim to apply this method to increase the efficacy of Cytarabine (Ara-c) to treat central nervous system leukemia (CNSL). In the present study, we validated this ultrasound contrast agent Sonovue^® targeting treatment via in vivo and in vitro experiments. The results showed that Sonovue^® combined with Cytarabine could significantly inhibit K562 cell (chronic myeloid leukemia cell line) proliferation. In the animal experiments, it has been shown that high dose Ara-c chemotherapy could prevent and cure CNSL effectively and the drug concentration in the brain was much higher compared with low dose Ara-c chemotherapy group. We certified that under ultrasound exposure Sonovue^® combined with low dose Cytarabine achieved an effective drug concentration in the rat brain, and brain tissue had no significant damage. Further animal experiments will be conducted to confirm these results in a leukemia animal model, considering the blood brain barrier is destroyed at different levels by leukemia cells. We hope this method will reduce the side effects of high-dose Cytarabine and improve the clinically high recurrence and poor prognosis of the central nervous system leukemia.