Murine IRF8 Mutation Offers New Insight into Osteoclast and Root Resorption.

Interferon regulatory factor 8 (IRF8), a transcription factor expressed in immune cells, functions as a negative regulator of osteoclasts and helps maintain dental and skeletal homeostasis. Previously, we reported that a novel mutation in the IRF8 gene increases susceptibility to multiple idiopathic cervical root resorption (MICRR), a form of tooth root resorption mediated by increased osteoclast activity. The IRF8 G388S variant in the highly conserved C-terminal motif is predicted to alter the protein structure, likely impairing IRF8 function. To investigate the molecular basis of MICRR and IRF8 function in osteoclastogenesis, we generated Irf8 knock-in (KI) mice using CRISPR/Cas9 technique modeling the human IRF8G388S mutation. The heterozygous (Het) and homozygous (Homo) Irf8 KI mice showed no gross morphological defects, and the development of hematopoietic cells was unaffected and similar to wild-type (WT) mice. The Irf8 KI Het and Homo mice showed no difference in macrophage gene signatures important for antimicrobial defenses and inflammatory cytokine production. Consistent with the phenotype observed in MICRR patients, Irf8 KI Het and Homo mice demonstrated significantly increased osteoclast formation and resorption activity in vivo and in vitro when compared to WT mice. The oral ligature-inserted Het and Homo mice displayed significantly increased root resorption and osteoclast-mediated alveolar bone loss compared to WT mice. The increased osteoclastogenesis noted in KI mice is due to the inability of IRF8G388S mutation to inhibit NFATc1-dependent transcriptional activation and downstream osteoclast specific transcripts, as well as its impact on autophagy-related pathways of osteoclast differentiation. This translational study delineates the IRF8 domain important for osteoclast function and provides novel insights into the IRF8 mutation associated with MICRR. IRF8G388S mutation mainly affects osteoclastogenesis while sparing immune cell development and function. These insights extend beyond oral health and significantly advance our understanding of skeletal disorders mediated by increased osteoclast activity and IRF8's role in osteoclastogenesis.

Extracts of Flavoparmelia sp. Inhibit Receptor Activator of Nuclear Factor-κB Ligand-Mediated Osteoclast Differentiation.

BACKGROUND: Osteoporosis is a geriatric disease with diminished bone density. The increase in the number of patients and medical expenses due to a global aging society are recognized as problems. Bone loss is the most common symptom of bone disease, not only osteoporosis but Paget's disease, rheumatoid arthritis, multiple myeloma, and other diseases. The main cause of this symptoms is excessive increase in the number and activity of osteoclasts. Osteoclasts are multinucleated giant cells that can resorb bone. They are differentiated and activation from monocytes/macrophages in the presence of macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand (RANKL). METHODS: The effect of extract of Flavoparmelia sp. (EFV), a genus of lichenized fungi within the Parmeliaceae, on the differentiation of bone marrow-derived macrophages (BMMs) into osteoclasts was examined by phenotype assay and the cell cytotoxicity was evaluated by cell counting kit-8. The osteoclast differentiation-related genes and proteins were investigated by real-time polymerase chain reaction and immunoblotting. The functional activity of osteoclast in response to EFV treatment was evaluated by an Osteo Assay plate. RESULTS: In this study, we found that EFV, a genus of lichenized fungi within the Parmeliaceae, inhibited osteoclast formation. And we investigated its inhibitory mechanism. EFV reduced RANKL-mediated osteoclast formation and activation by inhibiting expression of nuclear factor of activated T cells 1, a key factor of osteoclastogenesis. CONCLUSIONS: Taken together, our results show that EFV is a promising candidate for health functional foods or therapeutic agents that can help treat bone diseases such as osteoporosis.

Constant hypoxia inhibits osteoclast differentiation and bone resorption by regulating phosphorylation of JNK and IκBα.

BACKGROUND: Osteoclasts are responsible for the bone loss in rheumatoid arthritis (RA). Hypoxia has been suggested to play key roles in pathological bone loss. However, the current understanding of the effects of hypoxia on osteoclastogenesis is controversial. Effects of hypoxia on both the formation and function of osteoclasts requires examination. In the current study, we aimed to explore the effect of hypoxia on osteoclast differentiation and the underlying mechanisms. METHODS: RAW264.7 cells and murine bone-marrow-derived monocytes were used to induce osteoclastogenesis in the presence of macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa B ligand (RANKL). Hypoxic conditions were maintained in a hypoxic chamber at 5% CO2 and 1% O2, balanced with N2. Osteoclasts were detected by tartrate-resistant acid phosphatase (TRAP) staining. A bone resorption assay was carried out in vitro using bone slices. RT-PCR was conducted to detect osteoclast markers and transcription factors. The phosphorylation of nuclear factor-κBα (IκBα), c-Jun N-terminal kinase (JNK), extracellular regulated protein kinase (ERK), and p38 was detected by western blotting. Mann-Whitney U test or Student's t test was used to compare differences between the two groups. RESULTS: TRAP staining and the bone resorption assay revealed that hypoxia-restrained osteoclast differentiation and bone resorption. Expression of osteoclast markers including cathepsin K, RANK, and TRAP decreased during osteoclast differentiation under hypoxic conditions (all P < 0.05). Hypoxia at 1% O2 did not affect cell viability, whereas it dramatically abated RANKL-dependent phosphorylation of the JNK-mitogen-activated protein kinases (MAPK) and IκBα pathways. Moreover, the expression of nuclear factor of activated T-cell cytoplasmic 1 (NFATc1) was inhibited under hypoxic conditions (all P < 0.05). CONCLUSIONS: These results suggest that constant hypoxia at 1% O2 significantly restrains osteoclast formation and resorbing function without affecting cell viability. Constant hypoxia might inhibit RANKL-induced osteoclastogenesis by regulating NFATc1 expression via interfering the phosphorylation of JNK and IκBα.

The expression of nuclear factor of activated T cells in hepatocellular carcinoma and its relationship with clinicopathologic factors / 中华肝胆外科杂志

Objective To analyze the expression of activated T cell nuclear factor (NFAT) in hepatoeellular carcinoma (HCC) tissues and its correlation with clinicopathological factors.Methods Data of 105 patients including 87 males and 18 females,aged 55.1 ± 10.8 years old,diagnosed with HCC who underwent hepatectomy in hepatobiliary surgery department of the first central hospital of Tianjin from September 2014 to December 2016 were retrospectively analyzed,Immunohistochemical staining was used to detect the expression of NFAT subtypes in HCC tissues and adjacent normal liver tissues,and the differences in expression of NFAT subtypes and related factors were analyzed.Results HCC tissues had higher expression of NFAT4 and lower expression of NFAT1 compared to adjacent tissues (P＜0.05).NFAT1 positive group had higher HBV infected rate (93.1％ vs.78.7％) and lower microvascular invasion rate than that in NFAT1 negative group (24.1％ vs.46.8％) (P＜ 0.05).NFAT3 positive group had more younger patients (≤ 60 years old) (80.0％ vs.60.0％) and higher microvascular invasion rate (46.2％ vs.15.0％) (P＜0.05).NFAT4 positive group had higher microvascular invasion rate (43.3％ vs.22.2％) (P＜0.05).Conclusion HCC tissues had different expressions of NFATs.The expressions of NFAT1,NFAT3 and NFAT4 are related to microvascular invasion.

Extracts of Flavoparmelia sp. Inhibit Receptor Activator of Nuclear Factor-κB Ligand-Mediated Osteoclast Differentiation

BACKGROUND: Osteoporosis is a geriatric disease with diminished bone density. The increase in the number of patients and medical expenses due to a global aging society are recognized as problems. Bone loss is the most common symptom of bone disease, not only osteoporosis but Paget's disease, rheumatoid arthritis, multiple myeloma, and other diseases. The main cause of this symptoms is excessive increase in the number and activity of osteoclasts. Osteoclasts are multinucleated giant cells that can resorb bone. They are differentiated and activation from monocytes/macrophages in the presence of macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand (RANKL). METHODS: The effect of extract of Flavoparmelia sp. (EFV), a genus of lichenized fungi within the Parmeliaceae, on the differentiation of bone marrow-derived macrophages (BMMs) into osteoclasts was examined by phenotype assay and the cell cytotoxicity was evaluated by cell counting kit-8. The osteoclast differentiation-related genes and proteins were investigated by real-time polymerase chain reaction and immunoblotting. The functional activity of osteoclast in response to EFV treatment was evaluated by an Osteo Assay plate. RESULTS: In this study, we found that EFV, a genus of lichenized fungi within the Parmeliaceae, inhibited osteoclast formation. And we investigated its inhibitory mechanism. EFV reduced RANKL-mediated osteoclast formation and activation by inhibiting expression of nuclear factor of activated T cells 1, a key factor of osteoclastogenesis. CONCLUSIONS: Taken together, our results show that EFV is a promising candidate for health functional foods or therapeutic agents that can help treat bone diseases such as osteoporosis.

Role of CaN/NFATc4 signaling pathway in ventilator-induced lung injury / 中华麻醉学杂志

Objective To evaluate the role of calcineurin ( CaN)/nuclear factor of activated T cell cytoplasmic 4 protein ( NFATc4) signaling pathway in inflammatory responses in lung tissues of rats with ventilator-induced lung injury ( VILI) . Methods Twenty-four clean-grade healthy male Wistar rats, aged 5-8 weeks, weighing 220-250 g, were divided into 3 groups ( n=8 each) using a random number table method: control C (group C), VILI group and cyclosporine A plus VILI group (group CsA+VILI). The animals were anesthetized with pentobarbital and tracheostomized. The rats were mechanically ventilated for 6 h with the tidal volume set at 40 ml/kg and respiratory rate at 40 breaths/min to establish the model of VI-LI. The rats kept spontaneous breathing in group C. CaN specific inhibitor cyclosporine A 10 mg/kg was in-traperitoneally injected at 1 h before ventilation in group CsA+VILI. Rats were sacrificed immediately after ventilation, lung tissues were obtained and stained with hematoxylin and eosin to evaluate lung injury, broncho-alveolar lavage fluid was collected for determination of tumor necrosis factor-alpha ( TNF-α) , inter-leukin-1beta ( IL-1β) and IL-6 concentrations by enzyme-linked immunosorbent assay, and the lungs were removed for determination of the wet to dry weight ratio ( W/D ratio) , expression of intercellular adhesion molecule-1 ( ICAM-1) and vascular cell adhesion molecule-1 ( VCAM-1) ( by real-time polymerase chain reaction) , and expression of calcineurin and NFATc4 in lung tissues ( using Western blot ) . Results Compared with group C, the W/D ratio, lung injury scores and concentrations of IL-1β, IL-6 and TNF-αin BALF were significantly increased, and the expression of CaN, NFATc4, ICAM-1 mRNA and VCAM-1 mRNA was up-regulated in group VILI ( P＜0. 05) . Compared with group VILI, the W/D ratio, lung injury scores and concentrations of IL-1β, IL-6 and TNF-αin BALF were significantly decreased, and the expres-sion of CaN, NFATc4, ICAM-1 mRNA and VCAM-1 mRNA was down-regulated in group CsA+VILI ( P＜0. 05) . Conclusion CaN/NFATc4 signaling pathway mediates inflammatory responses in lung tissues of rats with VILI.

Expression and significance of nuclear factor of activated T-cells cytoplasmic 1 in hepatocellular carcinoma / 中华肝胆外科杂志

Objective To investigate the function of activated T cell nucleus factor 1 (NFATc1) in liver cancer tissues and the correlations between (NFATc1 and prognosis,and the effect of NFATc1 on liver cancer cell migration.Methods The hepatobiliary surgery department of Tianjin First Central Hospital collected 33 patients with hepatocellular carcinoma from January to June 2015,and studied the expression of NFATc1 in liver cancer and adjacent tissues and the prognosis of patients.HCC cell HepG2 were randomly divided into blank control group (without any intervention),interference group (infected with lentivirus interference sequence,down-regulated expression of NFATc1),and negative control group (infected with lentivirus negative control sequence).The relative expression of NFATc1 in the patients and the three groups were detected by real-time fluorescence quantitative polymerase chain reaction (rt-pcr),and the expressions of NFATc1,n-cadherin and e-cadherin in the three groups were detected by Western blot,and the migration of the cells was detected by Transwell.Results The mRNA level of NFATc1 in liver cancer tissues was higher than that in adjacent tissues,and the difference was statistically significant (P ＜ 0.05).According to the median expression of NFATc1,the 33 patients were divided into high-expression group (n =17) and low-expression group (n =16).The survival rate of the high-expression group was better than that of the low-expression group,and the difference was statistically significant (P ＜ 0.05).The mRNA level of NFATc1 in the interference group was lower than that in the negative control group and the blank control group,and the difference was statistically significant (P ＜0.05).The mRNA levels of NFATc1 and n-cadherin in the interference group were lower than those in the negative control group and the blank control group,while the mRNA levels of e-cadherin were higher than those in the negative control group and the blank control group,with statistically significant differences (P ＜ 0.05).The number of migrative cells in the interference group was (24.0 ± 5.6),which was lower than that in the blank control group [(69.0 ±4.0)] and the negative control group [(73.0 ±4.4)],and the difference was statistically significant (P ＜0.05).Conclusions The expression of NFATc1 is increased in liver cancer,and high level of NFATc1 indicated poor prognosis in liver cancer patients.Low expression of NFATc1 reduces the migration ability of liver cancer cells.

[Role of nuclear factor of activated T-cells cytoplasmic 1 on vascular calcification in rats with chronic renal failure].

Objective: To explore the role of nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) on vascular calcification in chronic renal failure rats. Methods: Nineteen male Sprague-Dawley (SD) rats were randomly divided into three groups: sham-operated group (n=6), 5/6 Nephrectomy (Nx) group (n=6), 5/6 Nx+ calcitriol group (n=7). Vascular calcification was determined by von Kossa staining and orthocresolphthalein complexone (OCPC) method. Protein expressions of NFATc1 and runt-related transcription factor 2 (Runx2) in aortas were measured by immunohistochemistry.In vitro, vascular smooth muscle cells (VSMCs) were primarily cultured and calcification was induced by ß-glycerophosphate (ß-GP). These cells were then randomly divided into control group, calcification group (10 mmol/L ß-GP) and cyclosporin A (CsA) intervention group (10 mmol/L ß-GP+ 1 µg/ml CsA). Calcium deposition was measured by Alizarin red staining and OCPC method; alkaline phosphatase (ALP) activity was measured by enzyme-linked immunosorbent assay. RT-PCR and Western blotting were used to observe the mRNA and protein expression of VSMCs NFATc1 and Runx2 respectively. Results: Compared to that in sham-operated and 5/6 Nx group, the expression of NFATc1 was obviously up-regulated in 5/6 Nx+ calcitriol group (7.20±0.46 vs 1.52±0.77, 2.04±1.31, P<0.05). In vitro, VSMCs calcification was successfully induced by high phosphorus environment, and RT-PCR and Western blotting showed that the expressions of NFATc1 and Runx2 were up-regulated (P<0.05). The calcification level in CsA intervention group was lower than that in calcification group [(60.86±7.95) vs (107.20±11.07) mg/g, P<0.05], and expression of Runx2 (mRNA and protein level) and ALP activity [(48.63±3.02) vs (98.75±3.46) U/g, P<0.05] decreased as well. Conclusion: NFATc1 contributes to accelerating vascular calcification in rat with chronic renal failure, the possible mechanism of which is that NFATc1 promotes VSMCs transformation to osteogenic phenotype.

Qibai Pingfei capsule medicated serum inhibits the proliferation of hypoxia-induced pulmonary arterial smooth muscle cells via the Ca2+/calcineurin/nuclear factor of activated T-cells 3 pathway.

OBJECTIVE: To observe the effect of Qibai Pingfei capsule (QBPF) medicated serum on the proliferation of rat pulmonary arterial smooth muscle cells (PASMCs) under hypoxia conditions and to investigate its key molecular effects on the Ca2+/calcineurin/nuclear factor of activated T-cells 3 (NFATc3) signaling pathway. METHODS: QBPF was provided to rats via continuous gavage for 10 days. Primary rat PASMCs were cultured using the direct adherent culture method. Methyl thiazolyl tetrazolium assay was used to evaluate the effect of QBPF on PASMCs proliferation under hypoxia conditions. Laser scanning confocal microscopy was used to detect changes in intracellular free calcium ([Ca2+]i) in PASMC-loaded Fluo-3-AM. Real-time quantitative polymerase chain reaction and western blot were used to detect the transcription and protein expression levels of calcineurin and NFATc3 genes in PASMCs. RESULTS: Compared with normoxia conditions, PASMCs proliferated at 12, 24, 48, and 72 h under hypoxia conditions. QBPF at concentrations of 5%, 10%, and 20% could inhibit hypoxia-induced PASMC proliferation to different degrees. The inhibitory effect was most significant in the 20% QBPF group under 24 h hypoxia conditions. The concentration of [Ca2+]i in PASMCs under hypoxia was increased and [Ca2+]i was significantly decreased when co-incubated with QBPF at 5%, 10%, and 20%. Compared with normoxia conditions, the mRNA and protein expression levels of calcineurin and NFATc3 in PASMCs induced by hypoxia were up-regulated. QBPF application significantly down-regulated mRNA and protein expression levels of calcineurin and NFATc3 in PASMCs. CONCLUSION: QBPF can effectively inhibit hypoxia-induced proliferation of PASMCs through down-regulation of key molecular expression via the Ca2+/calcineurin/NFATc3 pathway.

Regulation of NFATc1 in Osteoclast Differentiation.

Osteoclasts are unique cells that degrade the bone matrix. These large multinucleated cells differentiate from the monocyte/macrophage lineage upon stimulation by two essential cytokines, macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL). Activation of transcription factors such as microphthalmia transcription factor (MITF), c-Fos, NF-κB, and nuclear factor-activated T cells c1 (NFATc1) is required for sufficient osteoclast differentiation. In particular, NFATc1 plays the role of a master transcription regulator of osteoclast differentiation. To date, several mechanisms, including transcription, methylation, ubiquitination, acetylation, and non-coding RNAs, have been shown to regulate expression and activation of NFATc1. In this review, we have summarized the various mechanisms that control NFATc1 regulation during osteoclast differentiation.

Regulation of NFATc1 in Osteoclast Differentiation

Osteoclasts are unique cells that degrade the bone matrix. These large multinucleated cells differentiate from the monocyte/macrophage lineage upon stimulation by two essential cytokines, macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-kappa B (NF-kappaB) ligand (RANKL). Activation of transcription factors such as microphthalmia transcription factor (MITF), c-Fos, NF-kappaB, and nuclear factor-activated T cells c1 (NFATc1) is required for sufficient osteoclast differentiation. In particular, NFATc1 plays the role of a master transcription regulator of osteoclast differentiation. To date, several mechanisms, including transcription, methylation, ubiquitination, acetylation, and non-coding RNAs, have been shown to regulate expression and activation of NFATc1. In this review, we have summarized the various mechanisms that control NFATc1 regulation during osteoclast differentiation.

Recombinant mycobacterium tuberculosis heat shock protein 10 in human osteoclast differentiation / 中国组织工程研究

BACKGROUND:The mycobacterium tuberculosis heat shock protein 10 exerts effects on the osteoclasts by in vitro mouse cranium experiment, OBJECTIVE:To investigate the effect and mechanism of recombinant mycobacterium tuberculosis heat shock protein 10 (CPN10) on the differentiation of osteoclasts in the in vitro culture system that induces osteoclast differentiation. METHODHuman macrophage colony-stimulating factor-dependent adhesive blood mononuclear cells were divided into four groupreceptor activator for nuclear factor-κB ligand (RANKL)+CPN10 (1 mg/L), RANKL, CPN10 (1 mg/L), and negative control (complete culture medium). Monocytes were resuspended in a-MEM medium containing macrophage colony-stimulating factor, and were cultured in each group for 7, 14, 21 days. The morphology, quantity and bone resorption area of osteoclasts were examined by tartrate-resistant acid phosphatase (TRAP) staining. The expressions of NFATc1 and c-Fos gene and protein were also detected. RESULTS AND CONCLUSION:In negative control group, no TRAP-positive multinucleated osteoclasts generated, while in the other groups, TRAP-positive multinucleated osteoclasts differentiated and formed the lacunae in the smal bone grinding. The number of osteoclasts formation and resorption in CPN10 group were significantly lower than that in RANKL+CPN10 group. The expression of NFATc1 and c-Fos in the negative control group C was significantly lower than that of RANKL+CPN10 group and CPN10 group. However, CPN10 expressed NFATc1 and c-Fos protein, which was significantly lower than RANKL+CPN10 group. CPN10 is involved in the formation of osteoclasts, and the mechanism is related with the upregulation of NFATc1, c-Fos expression.

Nuclear factor of activated T cells negatively regulates expression of the tumor necrosis factor receptor-related 2 gene in T cells

Tumor necrosis factor receptor-related 2 (TR2, HVEM or TNFRSF-14) plays an important role in immune responses, however, the mechanisms regulating its expression are unclear. To understand the control of TR2 gene expression, we studied the upstream region of the gene. Gel supershift assays revealed inducible binding of nuclear factor of activated T cells (NFAT) to a putative NFAT site within the TR2 promoter. Furthermore, cotransfection of a dominant negative NFAT construct, or siRNA for NFAT, resulted in increased expression of a TR2 reporter gene. Our findings demonstrate that NFAT negatively regulates TR2 expression in activated T cells.

Influence of coal-arsenic exposure on human T cells proliferation and its mechanism / 中国地方病学杂志

Objective To explore the influence of coal-arsenic exposure on human T cells proliferation and its mechanism.Methods Blood samples colleoted from individuals which lived in arsenism area of coal-burning type and non-arsenism area in Guizhou Province were divided into exposed group(17),mild(35),moderate(38) and severe arsenism group(19)and control group(35)according to Diagnosis Smndard for Endemic Arsenism (WS/T 211-2001).T cell stimulation index wag determined by methyl thiazolyl tetrazolium(MTT)colorimetric method.The intracellular Ca2+ exponential(IECa2+)in peripheral blood mononuclear cell(PBMC)was analyzed by Fho-3/AM dye and flow cytometry.DNA binding activity of actively T cells nuclear factor(NF-AT)in PBMC was evaluated by electrophoretie mobility shift assay(EMSA).Results Concanavalin A(ConA)stimulation decreased the T cells stimulation indexes in exposed group,mild,moderate and severe arsenism groups(1.315±0.962, 1.611±1.224,1.114±0.545,1.289±0.875)compared with control group(2.322±1.241),all the differences being statistically significant(P＜0.01).After stimulated by anti-CD3 monoclonal antibody(McAb),the T cells stimulation index in exposed group,mild,moderate and severe arsenism group(0.997±0.177,1.103±0.291,1.007±0.221, 0.957±0.205) were lower than that of control group(1.842±0.429,P ＜ 0.01 ). IECa2+ of PBMC after treated by anti-CD3 McAb in mild,moderate and severe arsenism group( 110.130±49.637,92.429±31.191,77.640± 35.372) were lower compared with control group(145.986±59.450,P ＜0.01 ). Moreover,IECa2+ in moderat and severe arsenism group were lower than exposed group(121.337±46.410,P ＜ 0.05). DNA binding activity of PBMC NF-AT in mild,moderate and severe arsenism group(1.354±0.446,1.290±0.291,1.159±0.411 ) were lowered than that of control group(1.722±0.291,P ＜ 0.01) and exposed group(1.611±0.294,P ＜ 0.05). Conclusions The coal-arsenic exposure can reduce the human T cells stimulation indexes,IECa2+ in PBMC and the DNA binding activity of NF-AT. It suggest that arsenic may suppress the proliferation ability of human T cells,which may be partly related to the influence of arsenic on T cell receptor(TCR)/CD3 signal transduetion pathway.