Influence of perceived parental child-rearing attitudes and ego identity on college adjustment among Korean nursing students.

BACKGROUND: This study aimed to examine the relationship between nursing students' perceived parental child-rearing attitude, ego identity, and college adjustment in Korea and explore factors that influence college adjustment. METHODS: This study surveyed 224 nursing students enrolled in universities located in two regions within South Korea. Data were collected from October 14 to November 31, 2019. Perceived parental child-rearing attitude (paternal emotional warmth, paternal rejection, paternal overprotection, maternal emotional warmth, maternal rejection, and maternal overprotection) and ego identity of nursing students were used as independent variables on college adjustment. Collected data were subjected to correlation analysis using SPSS version 26.0 for Windows. Further, regression analysis was performed on the influence of parental child-rearing attitude and ego identity on college adjustment. RESULTS: Among the parental child-rearing attitudes, paternal emotional warmth (r = .30, p < .001), maternal emotional warmth (r = .38, p < .001), and ego identity (r = .71, p < .001) were positively correlated with nursing students' college adjustment, whereas maternal rejection was negatively correlated with ego identity (r = - .28, p < .001) and college adjustment (r = - .15, p = .025). Regression analysis of the effects of nursing students' perceived parental child-rearing attitude and ego identity on college adjustment, with grade as a control variable, revealed that ego identity (p < .001) had a significant effect on college adjustment, and the higher the ego identity (ß = 0.712), the higher the college adjustment. Further, the explanatory power of explaining college adjustment was high at 49.9%. CONCLUSIONS: The nursing students' perceived paternal emotional warmth, maternal emotional warmth, and ego identity were positively correlated with college adjustment. Additionally, ego identity was found as the influencing factor in Korean nursing students' college adjustment. Therefore, programs to strengthen ego identity should be developed and implemented for college adjustment among nursing students.

7-Ketocholesterol-Induced Micro-RNA-107-5p Increases Number and Activity of Osteoclasts by Targeting MKP1.

Osteoclasts (OCs), which are responsible for bone resorption, play a critical role in cholesterol-induced bone loss and recent studies have suggested that various micro-RNAs (miRs) contribute to modulating OCs. We hypothesized that 7-ketocholesterol (7-KC), a metabolite responsible for cholesterol-induced bone loss, induces miR-107-5p, which affects OCs. Overexpression and knock-down of miR-107-5p were performed using miR-107-5p mimic and anti-miR-107-5p, respectively. The effects of miR-107-5p on OCs were analyzed by tartrate-resistant alkaline phosphatase staining, qPCR, and Western blot. MiR-107-5p was upregulated after 7-KC exposure in receptor activator of nuclear factor kappa-Β ligand-stimulated OCs. Furthermore, miR-107-5p upregulation was also observed in tibiae from an atherogenic diet-fed mice compared with mice fed with a normal diet. MiR-107-5p overexpression enhanced the area and number of OCs, whereas inhibiting the endogenous expression of miR-107-5p generated by 7-KC had the opposite effect. Among the possible candidates, mitogen-activated protein kinase phosphatase-1, a stress-responsive dual-specificity phosphatase that inactivates mitogen-activated protein kinase (MKP1), has been proven to be a target gene of miR-107-5p, as demonstrated by the direct interaction between miR-107-5p and the 3'-untranslated region of MKP1. Collectively, our findings demonstrate that 7-KC-induced miR-107-5p promotes differentiation and function of OCs by downregulating MKP1.

Estrogen enhances browning in adipose tissue by M2 macrophage polarization via heme oxygenase-1.

Loss of ovarian function results in increased fat mass, leading to the accumulation of adipose tissue macrophages that participate in chronic inflammation. We hypothesized that ovariectomy (OVX)-induced increases in body weight and fat mass are associated with decreased adipose tissue (AT) browning due to estrogen (E2 ) deficiency. In mice, OVX decreased AT browning along with increased body weight, fat mass, and size of lipid droplets 12 weeks after surgery. Exogenous E2 recovered the OVX-induced changes. AT browning was enhanced by M2 macrophages induced by exogenous E2. E2 -induced M2 polarization occurred due to the increased expression of heme oxygenase-1 (HO-1) in macrophages, leading to decreased reactive oxygen species levels. Collectively, we demonstrated that E2 enhances AT browning via M2 polarization mediated by HO-1.

Fibroblast growth factor 21 deficiency aggravates obesity-induced hypothalamic inflammation and impairs thermogenic response.

OBJECTIVE AND DESIGN: Hypothalamic inflammation is closely associated with metabolic dysregulation. Fibroblast growth factor 21 (FGF21) is known to be an important metabolic regulator with anti-inflammatory properties. In this study, we investigated the effects of FGF21 deficiency on obesity-induced hypothalamic inflammation and thermogenic responses. MATERIALS AND METHODS: FGF21-deficient mice and/or wild-type (WT) mice were fed a high-fat diet (HFD) for 12 weeks. RESULTS: FGF21-deficient mice fed an HFD showed increased levels of inflammatory cytokines compared with WT obese control, and this was accompanied by upregulation of gliosis markers in the hypothalamus. Expression of heat-shock protein 72, a marker of neuronal damage, was increased in the FGF21-deficient obese mice, and the expression of hypothalamic neuronal markers involved in anti-thermogenic or thermogenic responses was altered. Moreover, the protein level of uncoupling protein 1 and other thermogenic genes were markedly reduced in the brown adipose tissue of the FGF21-deficient obese mice. CONCLUSIONS: These findings suggest that FGF21 deficiency aggravates obesity-induced hypothalamic inflammation and neuronal injury, leading to alterations in hypothalamic neural circuits accompanied by a reduction of the thermogenic response.

Carbon monoxide reverses adipose tissue inflammation and insulin resistance upon loss of ovarian function.

We hypothesized that carbon monoxide (CO) might suppress chronic inflammation, which led to metabolic disturbances. Ovariectomy (OVX) was performed in mice to mimic chronic inflammation secondary to loss of ovarian function. OVX increased fat mass and the infiltration of highly inflammatory CD11c cells into adipose tissue (AT), resulting in a disturbance of glucose metabolism. Treatment of CO attenuated these; CO decreased recruitment of CD11c-expressing cells in AT and reduced expression of CD11c in bone marrow-derived macrophages, protecting them from M1 polarization. Upregulated cGMP and decreased reactive oxygen species were responsible for the inhibitory activity of CO on CD11c expression; knockdown of soluble guanylate cyclase or heme oxygenase-1 using small interfering RNAs reduced this inhibition substantially. Improved OVX-induced insulin resistance (IR) by CO was highly associated with its activity to attenuate AT inflammation. Our results suggest a therapeutic value of CO to treat postmenopausal IR by reducing AT inflammation.

Reactive oxygen species induce the association of SHP-1 with c-Src and the oxidation of both to enhance osteoclast survival.

Loss of ovarian function causes oxidative stress as well as bone loss. We hypothesized that reactive oxygen species (ROS) induced by the failure of ovarian function are responsible for the bone loss by increasing the number of osteoclasts (OC). We found that ROS enhanced OC survival via Src homology 2 domain-containing phosphatase-1 (SHP-1), c-Src, Akt, and ERK. ROS induced the association of SHP-1 with c-Src as well as the oxidation of c-Src and SHP-1. This resulted in inactivation of SHP-1 and activation of c-Src via phosphorylation of Tyr(416). Knockdown of c-Src or SHP-1 abolished the effect of ROS on OC survival. Moreover, downregulation of SHP-1 upregulated activation of c-Src, Akt, and ERK in the absence of any stimulus, suggesting that inactivation of SHP-1 is required for OC survival. We demonstrated that the association and oxidation of c-Src and SHP-1 by ROS are key steps in enhancing OC survival, which are responsible for increased bone loss when ovarian function ceases.

Induction of heme oxygenase-1 with hemin reduces obesity-induced adipose tissue inflammation via adipose macrophage phenotype switching.

Adipose macrophages with the anti-inflammatory M2 phenotype protect against obesity-induced inflammation and insulin resistance. Heme oxygenase-1 (HO-1), which elicits antioxidant and anti-inflammatory activity, modulates macrophage phenotypes and thus is implicated in various inflammatory diseases. Here, we demonstrate that the HO-1 inducer, hemin, protects against obesity-induced adipose inflammation by inducing macrophages to switch to the M2 phenotype. HO-1 induction by hemin reduced the production of proinflammatory cytokines (TNF-α and IL-6) from cocultured adipocytes and macrophages by inhibiting the activation of inflammatory signaling molecules (JNK and NF-κB) in both cell types. Hemin enhanced transcript levels of M2 macrophage marker genes (IL-4, Mrc1, and Clec10a) in the cocultures, while reducing transcripts of M1 macrophage markers (CD274 and TNF-α). The protective effects of hemin on adipose inflammation and macrophage phenotype switching were confirmed in mice fed a high-fat diet, and these were associated with PPARγ upregulation and STAT6 activation. These findings suggest that induction of HO-1 with hemin protects against obesity-induced adipose inflammation through M2 macrophage phenotype switching, which is induced by the PPARγ and STAT6 pathway. HO-1 inducers such as hemin may be useful for preventing obesity-induced adipose inflammation.

7-Ketocholesterol plays a key role in cholesterol-induced hepatitis via macrophage and neutrophil infiltration.

This study sought to explore the role of 7-ketocholesterol (7-KC) in liver damage caused by high cholesterol intake and its potential pathological mechanism in mice. Our in vivo findings indicated that mice fed a high-cholesterol diet had elevated serum levels of 7-KC, accompanied by liver injury and inflammation, similar to human nonalcoholic steatohepatitis. Furthermore, the high-cholesterol diet induced neutrophil infiltration, which played a critical role in liver damage through myeloperoxidase (MPO) activity. Upon stimulation with 7-KC, macrophages exhibited increased expression of C-X-C motif chemokine ligand 1 (CXCL1) and CXCL2, as well as ATP-binding cassette transporter A1 (ABCA1) and ABCG1. Hepatocytes, on the other hand, exhibited increased expression of CXCL2 and ABCG1. The infiltration of neutrophils in the liver was primarily caused by CXCL1 and CXCL2, resulting in hepatocyte cell death due to elevated MPO activity. Our data also revealed that the activation of macrophages by 7-KC via ABCA1 or ABCG1 was not associated with lipid accumulation. Collectively, these findings suggest that high cholesterol-induced hepatitis in mice involves, at least partially, the recruitment of neutrophils to the liver by 7-KC-activated macrophages. This is mediated by increased expression of CXCL1 and CXCL2 through ABCA1 or ABCG1, which act as 7-KC efflux transporters. Additionally, hepatocytes contribute to this process by increased expression of CXCL2 through ABCG1. Therefore, our findings suggest that 7-KC may play a role in high cholesterol-induced hepatitis in mice by activating macrophages and hepatocytes, ultimately leading to neutrophil infiltration.

Overexpression of developmentally regulated GTP-binding protein-2 increases bone loss.

The developmentally regulated GTP-binding protein-2 (DRG2) is a novel subclass of GTP-binding proteins. Many functional characteristics of osteoclasts (OC) are associated with small GTPases. We hypothesized that DRG2 affects bone mass via modulating OC activity. Using DRG2 transgenic mice, we investigated the role of DRG2 in bone remodeling. DRG2 overexpression caused a decrease in bone mass and an increase in the number and activity of OC in vivo. DRG2 overexpression increased fusion, spreading, survival, and resorption activity of OC in vitro. Downregulation of DRG2 by siRNA decreased fusion, spreading, and survival of OC, supporting the observations found in DRG2 transgenic OC. Transgenic mature OCs were larger, with actin rings and higher ERK, Akt, Rac1 and Rho activities than wild-type OCs. Inhibition of these proteins abolished the effects of DRG2 on formation of large OCs with actin rings, implying that DRG2 affects cytoskeleton reorganization in a Rac1/Rho/ERK/Akt-dependent manner. In summary, DRG2 is associated with survival and cytoskeleton organization of OC under influence of macrophage colony-stimulating factor, and its overexpression leads to elevated bone resorptive activity of OC, resulting in bone loss.

Absence of MCP-1 leads to elevated bone mass via impaired actin ring formation.

Monocyte chemoattractant protein-1 (MCP-1) is associated with various inflammatory diseases involving bone loss, and is expressed along with its receptor by bone marrow-derived macrophages (BMM), which are osteoclast (OC) precursors. To investigate the role of MCP-1 in bone remodeling, we compared MCP-1-knockout (KO) mice with wild-type (WT) mice. The absence of MCP-1 increased bone mass and lowered serum collagen type I fragments (CTX-1) and TRACP 5b, but had no significant effect on the N-terminal propeptide of type I procollagen, suggesting that OCs are primarily responsible for the bone phenotype observed in the absence of MCP-1. MCP-1 deficiency resulted in reduced numbers and activity of OCs in vitro. It also led to a reduced level of c-Fms and receptor activator of nuclear factor-κB receptor and impaired actin ring formation. Activation of ERK, Akt, Rac1, and Rho upon M-CSF stimulation was also reduced and our evidence suggests that the aberrant actin ring formation was partly due to reduced activation of these molecules. Our findings point to a role of osteoclast MCP-1 in regulating bone remodeling. The higher bone mass in the femurs of MCP-1-KO mice could be, at least in part, due to decreased osteoclastogenesis and bone resorption resulting from aberrant M-CSF signaling in OCs.

Elevation of fibrinogen due to loss of ovarian function enhances actin ring formation and leads to increased bone resorption.

The aim of the present study was to evaluate the effect of fibrinogen on number and function of osteoclasts (OC) consequently resulting in bone loss. It was hypothesized that the enhanced level of released fibrinogen due to loss of ovarian function caused bone loss by acting on OCs. Bone loss was induced by ovariectomy (OVX) in mice and analyzed by micro-CT. The effect of fibrinogen on OCs was evaluated by tartrate-resistant acid phosphatase, annexin V, actin staining, pit formation observed on dentine slices, and Western blotting. Exogenous fibrinogen increased OC survival, actin ring formation, and bone resorption in vitro. The effect of fibrinogen was dependent on ß(3)-integrin, which is a marker for mature OCs. Fibrinogen induced the activation of transforming oncogene from Ak strain (Akt), Ras-related C3 botulinum toxin substrate 1 (Rac1), and Rho family of GTPase (Rho) and the degradation of the Bcl-2 interacting mediator of cell death (Bim) in a manner similar to macrophage colony-stimulating factor (M-CSF). OVX increased plasma fibrinogen and serum M-CSF together with elevated actin ring formation and bone loss. The increased fibrinogen level due to loss of ovarian function may contribute, at least partly, to bone loss through the enhanced number and activity of OCs.

Effects of Ego-Resiliency on Interpersonal Problems among Nursing Students: The Mediating Effects of Aggression.

(1) Background: Despite that nursing college students are more diverse than those in other majors, many nurses experience interpersonal problems and difficulties in the process of forming relationships and contacting various people. The purpose of this study is to understand the mediating effects of aggression on the process of ego-resilience in interpersonal problems in nursing college students. (2) Methods: The subjects of this study were 182 nursing college students attending university in D metropolitan city. Data were collected from 23 October to 9 November 2018. The measurements were carried out using the Ego-Resiliency Scale, the Aggression Questionnaire-Korean Version (AQ-K), and the short form of the KIIP Complex Scale (KIIP-SC). Data were analyzed using descriptive statistics, t-tests, and ANOVA. The methods of Baron and Kenny were used to verify the significance of the mediating effect. (3) Results: There were significant correlations among ego-resiliency, aggression, and interpersonal problems. Aggression had a partial mediating effect on the relationship between ego-resiliency and interpersonal problems, and aggression was explained to a level of 23%. (4) Conclusions: To lower interpersonal problems among nursing students, it is necessary to develop education and programs to improve ego-resiliency and to control aggression.

Structural Equation Model on the Problem Behavior of Adolescents.

This study aimed to explain direct and indirect relationship between psychological maltreatment, socio-psychological prevention factors, and problem behavior of adolescents based upon Jessor's protective-risk model and Haase's adolescent resilience model (ARM). A convenience sample of 138 Korean adolescents was recruited for the cross-sectional survey design. Using the collected data, the developed model was verified by structural equation modeling analysis using SPSS and AMOS program. Regarding model fit, χ2 = 151.62 (p < 0.001), GFI = 0.908, AGFI = 0.836, CFI = 0.911, SRMR = 0.060, and RMSEA = 0.10, showing acceptable fit levels. Psychological maltreatment explained 11.5% of perceived social support; psychological maltreatment, perceived social support, and self-control explained 89.9% of resilience; psychological maltreatment and perceived social support explained 53.2% of self-control; and psychological maltreatment, perceived social support, resilience, and self-control explained 39.7% of problem behavior. Psychological maltreatment directly and indirectly influenced perceived social support, self-control, and problem behavior. Psychological maltreatment and self-control were the factors that influence problem behavior of adolescents. The findings suggest that psychological maltreatment must be eradicated to reduce problem behavior of adolescents and enhance their socio-psychological protection factors.

High Cholesterol-Induced Bone Loss Is Attenuated by Arctiin via an Action in Osteoclasts.

High cholesterol-induced bone loss is highly associated with oxidative stress, which leads to the generation of oxysterols, such as 7-ketocholesterol (7-KC). Here, we conducted in vivo and in vitro experiments to determine whether arctiin prevents high cholesterol diet-induced bone loss by decreasing oxidative stress. First, arctiin was orally administered to atherogenic diet (AD)-fed C57BL/6J male mice at a dose of 10 mg/kg for 6 weeks. Micro-computerized tomography (µCT) analysis showed that arctiin attenuated AD-induced boss loss. For our in vitro experiments, the anti-oxidant effects of arctiin were evaluated in 7-KC-stimulated osteoclasts (OCs). Arctiin decreased the number and activity of OCs and inhibited autophagy by disrupting the nuclear localization of transcription factor EB (TFEB) and downregulating the oxidized TFEB signaling pathway in OCs upon 7-KC stimulation. Furthermore, arctiin decreased the levels of reactive oxygen species (ROS) by enhancing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), catalase, and heme oxygenase 1 (HO-1), all of which affected OC differentiation. Conversely, silencing of Nrf2 or HO-1/catalase attenuated the effects of arctiin on OCs. Collectively, our findings suggested that arctiin attenuates 7-KC-induced osteoclastogenesis by increasing the expression of ROS scavenging genes in the Nrf2/HO-1/catalase signaling pathway, thereby decreasing OC autophagy. Moreover, arctiin inhibits the oxidation and nuclear localization of TFEB, thus protecting mice from AD-induced bone loss. Our findings thus demonstrate the therapeutic potential of arctiin for the prevention of cholesterol-induced bone loss.

Doxorubicin Induces Bone Loss by Increasing Autophagy through a Mitochondrial ROS/TRPML1/TFEB Axis in Osteoclasts.

Doxorubicin (DOX), a widely used chemotherapeutic agent, has been linked to an increased risk of bone damage in human patients and induces bone loss in mice. DOX induces autophagy, which contributes to bone homeostasis and excess autophagy in osteoclasts (OCs), resulting in bone loss. We hypothesized that DOX-induced bone loss is caused by the induction of autophagy in OCs. In vitro, DOX significantly increased the area of OCs and bone resorption activity, whereas it decreased OC number through apoptosis. DOX enhanced the level of LC3II and acidic vesicular organelles-containing cells in OCs, whereas an autophagy inhibitor, 3-methyladenine (3-MA), reversed these, indicating that enhanced autophagy was responsible for the effects of DOX. Increased mitochondrial reactive oxygen species (mROS) by DOX oxidized transient receptor potential mucolipin 1 (TRPML1) on the lysosomal membrane, which led to nuclear localization of transcription factor EB (TFEB), an autophagy-inducing transcription factor. In vivo, micro-computerized tomography analysis revealed that the injection of 3-MA reversed DOX-induced bone loss, and tartrate-resistant acid phosphatase staining showed that 3-MA reduced the area of OCs on the bone surface, which was enhanced upon DOX administration. Collectively, DOX-induced bone loss is at least partly attributable to autophagy upregulation in OCs via an mROS/TRPML1/TFEB axis.

Morin Disrupts Cytoskeleton Reorganization in Osteoclasts through an ROS/SHP1/c-Src Axis and Grants Protection from LPS-Induced Bone Loss.

Morin is a naturally occurring flavonoid with anti-inflammatory and antioxidative properties. Therefore, we hypothesized that morin may prevent inflammatory bone loss by reducing oxidative stress. To investigate the effect of morin on inflammatory bone loss, mice were injected with lipopolysaccharide (LPS). Osteoclasts (OCs) were analyzed by tartrate-resistant acid phosphatase (TRAP) staining and actin ring formation. Micro-computerized tomography analysis indicated that morin prevented LPS-induced bone loss in mice. In vivo TRAP staining indicated that morin decreased the number and surface of the OCs that were increased in LPS-treated mice. Furthermore, in vitro experiments indicated that morin decreased the number and activity of OCs upon LPS stimulation. Morin decreased actin ring-containing OCs with decreased activation of c-Src (Y416)/vav guanine nucleotide exchange factor 3/Ras-related C3 botulinum toxin substrate 1 compared with LPS alone. Morin decreased cytosolic reactive oxygen species (ROS), thus preventing the oxidation of Src homology region 2 domain-containing phosphatase 1 (SHP-1), followed by the inactivation of c-Src via direct interaction with SHP1. Conversely, SHP1 knockdown abolished the inhibitory effect of morin on OCs. Therefore, our findings suggest that morin disrupted cytoskeletal reorganization via an ROS/SHP1/c-Src axis in OCs, thereby granting protection from LPS-induced bone loss, which demonstrates its therapeutic potential against inflammatory bone loss.

Estrogen Decreases Cytoskeletal Organization by Forming an ERα/SHP2/c-Src Complex in Osteoclasts to Protect against Ovariectomy-Induced Bone Loss in Mice.

Loss of ovarian function is closely related to estrogen (E2) deficiency, which is responsible for increased osteoclast (OC) differentiation and activity. We aimed to investigate the action mechanism of E2 to decrease bone resorption in OCs to protect from ovariectomy (OVX)-induced bone loss in mice. In vivo, tartrate-resistant acid phosphatase (TRAP) staining in femur and serum carboxy-terminal collagen crosslinks-1 (CTX-1) were analyzed upon E2 injection after OVX in mice. In vitro, OCs were analyzed by TRAP staining, actin ring formation, carboxymethylation, determination of reactive oxygen species (ROS) level, and immunoprecipitation coupled with Western blot. In vivo and in vitro, E2 decreased OC size more dramatically than OC number and Methyl-piperidino-pyrazole hydrate dihydrochloride (MPPD), an estrogen receptor alpha (ERα) antagonist, augmented the OC size. ERα was found in plasma membranes and E2/ERα signaling affected receptor activator of nuclear factor κB ligand (RANKL)-induced actin ring formation by rapidly decreasing a proto-oncogene tyrosine-protein kinase, cellular sarcoma (c-Src) (Y416) phosphorylation in OCs. E2 exposure decreased physical interactions between NADPH oxidase 1 (NOX1) and the oxidized form of c-Src homology 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2), leading to higher levels of reduced SHP2. ERα formed a complex with the reduced form of SHP2 and c-Src to decrease c-Src activation upon E2 exposure, which blocked a signal for actin ring formation by decreased Vav guanine nucleotide exchange factor 3 (Vav3) (p-Y) and Ras-related C3 botulinum toxin substrate 1 (Rac1) (GTP) activation in OCs. E2/ERα signals consistently inhibited bone resorption in vitro. In conclusion, our study suggests that E2-binding to ERα forms a complex with SHP2/c-Src to attenuate c-Src activation that was induced upon RANKL stimulation in a non-genomic manner, resulting in an impaired actin ring formation and reducing bone resorption.

7-ketocholesterol enhances autophagy via the ROS-TFEB signaling pathway in osteoclasts.

Oxysterols play a critical role in human health and diseases associated with high cholesterol and oxidative stress. Given that a positive correlation was observed between cholesterol and collagen type 1 fragment (CTX-1) or serum reactive oxygen species (ROS) in humans, we hypothesized that oxidized cholesterol metabolites may participate in cholesterol-induced bone loss. Therefore, this study aimed to identify the metabolite responsible for cholesterol-associated bone loss and evaluate its effect on osteoclasts (OCs) leading to bone loss. An atherogenic diet in mice increased the levels of the oxysterol, 7-ketocholesterol (7-KC) in bone, as well as serum ROS. 7-KC increased the number and activity of OCs by enhancing autophagy via the ROS-transcription factor EB signaling pathway. These findings suggest that 7-KC acts as a cholesterol metabolite and is at least partially responsible for cholesterol-induced bone loss by inducing autophagy in OCs.

Saturated fatty acids enhance osteoclast survival.

Hyperlipidemia and marrow fat are associated with lowering bone density in vivo, suggesting that lipid contributes to bone loss. Using bone marrow-derived macrophages, we investigated the effect of saturated fatty acids (SFA) on osteoclastogenesis. The level of free fatty acids and adiposity in bone marrow was significantly elevated in obese mice. SFA increased osteoclast (OC) survival by preventing apoptosis. SFA caused the production of MIP-1alpha and led to activation of nuclear factor (NF)-kappaB in the OC. The absence of Toll-like receptor 4 (TLR4) or myeloid differentiation factor 88 (MyD88) abolished the survival effect of SFA on OC.

Gold nanoparticles inhibited the receptor activator of nuclear factor-κb ligand (RANKL)-induced osteoclast formation by acting as an antioxidant.

Gold nanoparticles inhibited osteoclast (OC) formation induced by the receptor activator of nuclear factor-κB ligand (RANKL) in bone marrow-derived macrophages (BMMs). This was accompanied by a decreased level of tartrate-resistant alkaline phosphatase (TRAP) and less activation of nuclear factor (NF)-κB. The nanoparticles also reduced the production of reactive oxygen species (ROS) in response to RANKL and upregulated RANKL-induced glutathione peroxidase-1 (Gpx-1), suggesting a role as an antioxidant in the BMM. The inhibitory effects on OC formation might have been due to elevated defense against oxidative stress.