Role of MafB in macrophages Hamada, Michito; Tsunakawa, Yuki; Jeon, Hyojung ...
Experimental Animals,
01/2020, Letnik:
69, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The transcription factor MafB regulates macrophage differentiation. However, studies on the phenotype of Mafb-deficient macrophages are still limited. Recently, it was shown that the specific ...expression of MafB permits macrophages to be distinguished from dendritic cells. In addition, MafB has been reported to be involved in various diseases related to macrophages. Studies using macrophage-specific Mafb-deficient mice show that MafB is linked to atherosclerosis, autoimmunity, obesity, and ischemic stroke, all of which exhibit macrophage abnormality. Therefore, MafB is hypothesized to be indispensable for the regulation of macrophages to maintain systemic homeostasis and may serve as an innovative target for treating macrophage-related diseases.
We examined various methods to enhance the accessibility of intracytoplasmic sperm injection (ICSI) technology to more users by making the technique easier, more efficient, and practical. First, the ...methods for artificially removing the mouse sperm tail were evaluated. Trypsin treatment was found to efficiently remove the sperm tails. The resultant sperm cells had a lower oocyte activation capacity; however, the use of activated oocytes resulted in the same fecundity as that of fresh, untreated sperm. Pre-activated oocytes were more resistant to physical damage, showed higher survival rates, and required less time per injection. Testing this method in rats yielded similar results, although the oocyte activation method was different. Remarkably, this method resulted in higher birth rates of rat progeny than with conventional methods of rat ICSI. Our method thereby streamlines mouse and rat ICSI, making it more accessible to laboratories across many disciplines.
Spaceflight causes a decrease in skeletal muscle mass and strength. We set two murine experimental groups in orbit for 35 days aboard the International Space Station, under artificial earth-gravity ...(artificial 1 g; AG) and microgravity (μg; MG), to investigate whether artificial 1 g exposure prevents muscle atrophy at the molecular level. Our main findings indicated that AG onboard environment prevented changes under microgravity in soleus muscle not only in muscle mass and fiber type composition but also in the alteration of gene expression profiles. In particular, transcriptome analysis suggested that AG condition could prevent the alterations of some atrophy-related genes. We further screened novel candidate genes to reveal the muscle atrophy mechanism from these gene expression profiles. We suggest the potential role of Cacng1 in the atrophy of myotubes using in vitro and in vivo gene transductions. This critical project may accelerate the elucidation of muscle atrophy mechanisms.
In order to increase the contribution of donor HSC cells, irradiation and DNA alkylating agents have been commonly used as experimental methods to eliminate HSCs for adult mice. But a technique of ...HSC deletion for mouse embryo for increase contribution of donor cells has not been published. Here, we established for the first time a procedure for placental HSC transplantation into E11.5 Runx1-deficient mice mated with G1-HRD-Runx1 transgenic mice (Runx1
::Tg mice) that have no HSCs in the fetal liver. Following the transplantation of fetal liver cells from mice (allogeneic) or rats (xenogeneic), high donor cell chimerism was observed in Runx1
::Tg embryos. Furthermore, chimerism analysis and colony assay data showed that donor fetal liver hematopoietic cells contributed to both white blood cells and red blood cells. Moreover, secondary transplantation into adult recipient mice indicated that the HSCs in rescued Runx1
::Tg embryos had normal abilities. These results suggest that mice lacking fetal liver HSCs are a powerful tool for hematopoiesis reconstruction during the embryonic stage and can potentially be used in basic research on HSCs or xenograft models.
Mouse embryonic stem cells (ESCs) are pluripotent stem cells, which have the ability to differentiate into all three germ layers: mesoderm, endoderm, and ectoderm. Proper levels of phosphorylated ...extracellular signal-regulated kinase (pERK) are critical for maintaining pluripotency, as elevated pERK evoked by fibroblast growth factor (FGF) receptor activation results in differentiation of ESCs, while, conversely, reduction of pERK by a MEK inhibitor maintains a pluripotent ground state. However, mechanisms underlying proper control of pERK levels in mouse ESCs are not fully understood. Here, we find that Klf5, a Krüppel-like transcription factor family member, is a component of pERK regulation in mouse ESCs. We show that ERK signaling is overactivated in Klf5-KO ESCs and the overactivated ERK in Klf5-KO ESCs is suppressed by the introduction of Klf5, but not Klf2 or Klf4, indicating a unique role for Klf5 in ERK suppression. Moreover, Klf5 regulates Spred1, a negative regulator of the FGF-ERK pathway. Klf5 also facilitates reprogramming of EpiSCs into a naïve state in combination with a glycogen synthase kinase 3 inhibitor and LIF, and in place of a MEK inhibitor. Taken together, these results show for the first time that Klf5 has a unique role suppressing ERK activity in mouse ESCs.
Secondary lymphoid organs are critical for regulating acquired immune responses. The aim of this study was to characterize the impact of spaceflight on secondary lymphoid organs at the molecular ...level. We analysed the spleens and lymph nodes from mice flown aboard the International Space Station (ISS) in orbit for 35 days, as part of a Japan Aerospace Exploration Agency mission. During flight, half of the mice were exposed to 1 g by centrifuging in the ISS, to provide information regarding the effect of microgravity and 1 g exposure during spaceflight. Whole-transcript cDNA sequencing (RNA-Seq) analysis of the spleen suggested that erythrocyte-related genes regulated by the transcription factor GATA1 were significantly down-regulated in ISS-flown vs. ground control mice. GATA1 and Tal1 (regulators of erythropoiesis) mRNA expression was consistently reduced by approximately half. These reductions were not completely alleviated by 1 g exposure in the ISS, suggesting that the combined effect of space environments aside from microgravity could down-regulate gene expression in the spleen. Additionally, plasma immunoglobulin concentrations were slightly altered in ISS-flown mice. Overall, our data suggest that spaceflight might disturb the homeostatic gene expression of the spleen through a combination of microgravity and other environmental changes.
The large Maf transcription factors c-Maf and MafB are expressed in macrophage-lineage hematopoietic cells, but the expression patterns of MafB and c-Maf in macrophage subtypes and tissue-resident ...macrophages have not been fully analyzed. First, we analyzed MafB and c-Maf protein expression in tissue-resident macrophages. Mouse lymph nodes, spleens, lungs, and kidneys were subjected to immunohistochemistry using anti-MafB and anti-c-Maf. Both MafB and c-Maf signals were observed in lymph node macrophages. In the splenic macrophages the MafB signal was detected by anti-MafB, but the c-Maf signal was not detected. No expression of c-Maf or MafB was detected in macrophages in the lung and kidney. Flow cytometry analysis revealed a similar pattern of GFP expression in Mafb/GFP knock-in heterozygous mice. To analyze these different expression patterns in greater detail, we examined the expression of MafB and c-Maf by quantitative RT-PCR in different cytokine- or LPS-induced macrophages in vitro. MafB expression was induced by IL-10 or IL-4 with IL-13 and was reduced by LPS or GM-CSF. By contrast, c-Maf expression was induced by IL-10 and reduced by IL-4 with IL-13 or GM-CSF. These results indicate that MafB and c-Maf have different expression patterns in macrophages, suggesting differences in function.
The transcription factor MafB is specifically expressed in macrophages. We have recently demonstrated that MafB is expressed in anti-inflammatory alternatively activated M2 macrophages in vitro. ...Tumor-associated macrophages (TAMs) are a subset of M2 type macrophages that can promote immunosuppressive activity, induce angiogenesis, and promote tumor cell proliferation. To examine whether MafB express in TAMs, we analyzed green fluorescent protein (GFP) expression in Lewis lung carcinoma tumors of MafB-GFP knock-in heterozygous mice. FACS analysis demonstrated GFP fluorescence in cells positive for macrophage-markers (F4/80, CD11b, CD68, and CD204). Moreover, quantitative RT-PCR analysis with F4/80+GFP+ and F4/80+GFP− sorted cells showed that the GFP-positive macrophages express IL-10, Arg-1, and TNF-α, which were known to be expressed in TAMs. These results indicate that MafB is expressed in TAMs. Furthermore, immunostaining analysis using an anti-MAFB antibody revealed that MAFB is expressed in CD204-and CD68-positive macrophages in human lung cancer samples. In conclusion, MafB can be a suitable marker of TAMs in both mouse and human tumor tissues.
•The GFP was expressed in Lewis lung carcinoma tumors in MafB-GFP knock-in hetero mice.•The marker genes of TAMs were highly expressed in F4/80+GFP+ macrophages.•MAFB was expressed in TAMs in human lung cancer samples, and can be used to assess tumor malignancy.
Pluripotency is maintained in mouse embryonic stem (ES) cells and is induced from somatic cells by the activation of appropriate transcriptional regulatory networks. Krüppel-like factor gene family ...members, such as Klf2, Klf4 and Klf5, have important roles in maintaining the undifferentiated state of mouse ES cells as well as in cellular reprogramming, yet it is not known whether other Klf family members exert self-renewal and reprogramming functions when overexpressed. In this study, we examined whether overexpression of any representative Klf family member, such as Klf1-Klf10, would be sufficient for the self-renewal of mouse ES cells. We found that only Klf2, Klf4, and Klf5 produced leukemia inhibitory factor (LIF)-independent self-renewal, although most KLF proteins, if not all, have the ability to occupy the regulatory regions of Nanog, a critical Klf target gene. We also examined whether overexpression of any of Klf1-Klf10 would be sufficient to convert epiblast stem cells into a naïve pluripotent state and found that Klf5 had such reprogramming ability, in addition to Klf2 and Klf4. We also delineated the functional domains of the Klf2 protein for LIF-independent self-renewal and reprogramming. Interestingly, we found that both the N-terminal transcriptional activation and C-terminal zinc finger domains were indispensable for this activity. Taken together, our comprehensive analysis provides new insight into the contribution of Klf family members to mouse ES self-renewal and cellular reprogramming.
Focal segmental glomerulosclerosis (FSGS) is a common cause of steroid-resistant nephrotic syndrome. Spontaneous remission of FSGS is rare and steroid-resistant FSGS frequently progresses to renal ...failure. Many inheritable forms of FSGS have been described, caused by mutations in proteins that are important for podocyte function. Here, we show that a basic leucine zipper transcription factor, MafB, protects against FSGS. MAFB expression was found to be decreased in the podocytes of patients with FSGS. Moreover, conditional podocyte-specific MafB-knockout mice developed FSGS with massive proteinuria accompanied by depletion of the slit diaphragm-related proteins (Nphs1 and Magi2), and the podocyte-specific transcription factor Tcf21. These findings indicate that MafB plays a crucial role in the pathogenesis of FSGS. Consistent with this, adriamycin-induced FSGS and attendant proteinuria were ameliorated by MafB overexpression in the podocytes of MafB podocyte-specific transgenic mice. Thus, MafB could be a new therapeutic target for FSGS.
Display omitted
PDF
