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1.
Vet Sci ; 8(10)2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34679063

RESUMO

Bones play an important role in maintaining the level of calcium in blood. They provide support for soft tissues and hematopoiesis and undergo continuous renewal throughout life. In addition, vitamin D is involved in regulating bone and calcium homeostasis. Galectin-3 (Gal-3) is a ß-galactoside-binding protein that can regulate bone cell differentiation and function. Here, we aimed to study the regulatory effects of Gal-3 on vitamin-D-regulated osteoclastogenesis and bone resorption in chicken. Gal-3 expression in bone marrow stromal cells (BMSCs) from 18-day-old chicken embryos was inhibited or overexpressed. BMSCs were then co-cultured with bone marrow monocytes/macrophages (BMMs) with or without addition of 1α,25(OH)2D3. The results showed that 1α,25(OH)2D3 upregulated the expression of Gal-3 mRNA and receptor activator of nuclear-factor κB ligand (RANKL) expression in BMSCs and promoted osteoclastogenesis, as shown by the upregulated expression of osteoclast (OC) markers (CtsK, CAII, MMP-9, and TRAP) and increased bone resorption, a method for measuring the bone resorption area in vitro. Knockdown of Gal-3 by small-interfering RNA (siRNA) in BMSCs downregulated the expression of RANKL mRNA and attenuated the effects of 1α,25(OH)2D3 on osteoclastogenesis and bone resorption. Conversely, overexpression of Gal-3 in BMSCs enhanced the effects of osteoclastogenesis and bone resorption by increasing the expression of RANKL mRNA. These results demonstrated that Gal-3 mediates the differentiation and bone resorption of osteoclasts regulated by 1α,25(OH)2D3.

2.
Ecotoxicol Environ Saf ; 227: 112895, 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34673407

RESUMO

Cadmium is an environmental pollutant that threatens the health of both humans and animals. Current studies have shown that while hepatotoxic damage induced by cadmium is closely related to autophagy, its intrinsic mechanism has not been elucidated. MicroRNA plays a regulatory role on different stages of autophagy. In this study, we investigated the mechanisms by which microRNA-155 (miR-155) regulate cadmium-induced hepatotoxicity in rat hepatocytes (BRL 3A cells) and in vivo. We found that cadmium exposure could cause liver injury in rats, resulting in a decreased liver index, increased alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activity, hepatocyte steatosis, and ultrastructure damage. Cadmium exposure also induced autophagy in hepatocytes, resulting in increased expression of ATG5, Belin1, LC3II, and an increased number of autophagosomes. In addition, cadmium exposure upregulated miR-155 expression, downregulated Rheb mRNA expression, and downregulated the level of protein expression in the Rheb/mTOR signaling pathway in rat hepatocytes. The overexpression of miR-155 followed by cadmium exposure upregulated the level of autophagy in BRL3A cells, whereas miR-155 inhibition had the opposite effect. In addition, miR-155 negatively regulated Rheb. A dual-luciferase reporter assay verified the negative regulatory effect of miR-155 on Rheb targeting. Knockdown of Rheb downregulated cadmium-induced autophagy. Therefore, the Rheb/mTOR signaling can negatively regulate autophagy. The present study demonstrates that miR-155 promotes cadmium-induced autophagy in rat hepatocytes by suppressing Rheb expression.

3.
Ecotoxicol Environ Saf ; 224: 112620, 2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34392152

RESUMO

Cadmium (Cd) has been described as a potential inflammatory inducer, while increasing evidence shows that inappropriate inflammation is a contributing factor to kidney injury. Hence, research on Cd-triggered inflammatory response is of great significance for elucidating the mechanism of Cd-induced nephrotoxicity. Bromodomain-containing 4 (BRD4) is an important epigenetic regulator involved in the development of many inflammatory diseases, but its regulatory roles in Cd-triggered inflammatory response remain to be clarified. Here, we found that treatment with Cd in Sprague-Dawley rats (2 mg/kg bw, i.p., 5 consecutive days) and in rat kidney cell line (NRK-52E, 0-10 µM, 12 h) induced the transcription of inflammatory cytokines, which could be reduced by JQ1 (BRD4 inhibitor, 25 mg/kg bw, i.p., 3 consecutive days in vivo; 0.5 µM, 12 h in vitro) or BRD4 small interfering RNA (siRNA, in vitro), suggesting that BRD4 participates in Cd-triggered inflammatory response. Next, our study clarified the roles of BRD4 in Cd-triggered inflammatory response. The inhibition of BRD4 decreased Cd-promoted NF-κB nuclear translocation and activation in vivo and in vitro. Cd increased the acetylation level of RelA K310 and enhanced BRD4 binding to acetylated NF-κB RelA in vivo and in vitro, which were abrogated by inhibiting BRD4. In summary, our study suggests that BRD4 is involved in Cd-triggered transcription of inflammatory cytokines by mediating the activation of NF-κB signaling pathway and increasing itself binding to acetylated NF-κB RelA in rat kidney, therefore, BRD4 could be a potential therapeutic target for Cd-induced renal diseases.

4.
Differentiation ; 121: 35-43, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34454349

RESUMO

Osteoclastogenesis is induced by receptor activator of nuclear factor-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF), and can be suppressed by osteoprotegerin (OPG). Beclin1 has a dual role in osteoclastogenesis. However, the role of Beclin1-mediated autophagy during OPG-induced inhibition of osteoclastogenesis remains unclear. Here, we found that Beclin1 and matrix metalloproteinase 9 (MMP-9) expression were increased during osteoclastogenesis. OPG (20, 40, and 80 ng/mL) decreased Src and MMP-9 expression, but augmented Beclin1 expression and fluorescence intensity. Similarly, treatment with the autophagy activator rapamycin increased Beclin1 expression during OPG-induced inhibition of osteoclastogenesis. Further, Beclin1 knockdown restored osteoclast numbers by reducing autophagy during OPG-induced inhibition of osteoclastogenesis. These results indicate that Beclin1 has a positive role during OPG-induced inhibition of osteoclastogenesis by regulating autophagy, which might provide a potential basis for osteoclastogenesis.

5.
Biomolecules ; 11(7)2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34356602

RESUMO

Cadmium (Cd) is a potential pathogenic factor in the nervous system associated with various neurodegenerative disorders. Puerarin (Pur) is an isoflavone purified from the Chinese medical herb, kudzu root, and exhibits antioxidant and antiapoptotic properties in the brain. In this study, the detailed mechanisms underlying the neuroprotective potential of Pur against Cd-induced neuronal injury was evaluated for the first time in vivo in a rat model and in vitro using primary rat cerebral cortical neurons. The results of the in vivo experiments showed that Pur ameliorated Cd-induced neuronal injury, reduced Cd levels in the cerebral cortices, and stimulated Cd excretion in Cd-treated rats. We also observed that the administration of Pur rescued Cd-induced oxidative stress, and attenuated Cd-induced apoptosis by concomitantly suppressing both the Fas/FasL and mitochondrial pathways in the cerebral cortical neurons of rats both in vivo and in vitro. Our results demonstrate that Pur exerted its neuroprotective effects by stimulating Cd excretion, ameliorating Cd-induced oxidative stress and apoptosis in rat cerebral cortical neurons.


Assuntos
Apoptose/efeitos dos fármacos , Cádmio , Córtex Cerebral , Isoflavonas/farmacologia , Neurônios/metabolismo , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Cádmio/farmacocinética , Cádmio/toxicidade , Córtex Cerebral/lesões , Córtex Cerebral/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley
6.
J Agric Food Chem ; 69(32): 9451-9460, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34372660

RESUMO

Lead (Pb) is a common toxic heavy metal pollutant in the environment that seriously endangers the health of animals. The liver is a key target organ affected by Pb toxicity. Plant extracts allicin and quercetin have a strong antioxidant capacity that can promote the excretion of heavy metals by improving the body's antioxidant defense and chelating heavy metal ions. To explore the preventive and therapeutic effects of allicin and quercetin on Pb poisoning in chickens, 96 chickens were randomly divided into eight groups: control, Pb, allicin, quercetin, allicin + quercetin, Pb + allicin, Pb + quercetin, and Pb + allicin + quercetin groups. The chickens were given feed containing the above treatments for 90 days. The results indicated that Pb can affect the growth and development of the liver, damage the circulatory system, destroy the structure of mitochondria and nuclei in liver cells, cause an imbalance in the oxidation system, inhibit PI3K protein, and activate the mitochondrial apoptotic pathway. Allicin and quercetin, alone or in combination, can improve the antioxidant capacity of the liver and alleviate liver tissue damage caused by Pb. In summary, allicin and quercetin could alleviate oxidative damage and apoptosis in the Pb-poisoned chicken liver through the PI3K signaling pathway, with stronger effects achieved by their combination.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Quercetina , Animais , Galinhas , Dissulfetos , Chumbo/toxicidade , Estresse Oxidativo , Fosfatidilinositol 3-Quinases/genética , Transdução de Sinais , Ácidos Sulfínicos
7.
Environ Pollut ; 284: 117514, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34261220

RESUMO

Based on the fact that mycotoxins and the food-borne bacteria coexist in the natural environment and pose a significant health hazard to humans and animals, it is important to investigate the immunosuppressive mechanism of ZEA (zearalenone), DON (deoxynivalenol), and their combination in bacterial infections. In this study, we established a mouse model of mycotoxin low-dose exposure combined with Listeria monocytogenes infection and investigated the effects of ZEA, DON and their combination on Th1-mediated anti-intracellular bacterial infection based on CD4+ T cell activation and differentiation using both in vitro and in vivo analyses. The present study showed that both ZEA and DON aggravated Listeria monocytogenes infection in mice and affected the activation of CD4+ T cells and Th1 differentiation, including the effects on costimulatory molecules CD28 and CD152 and on cross-linking of IL-12 and IL-12R, by inhibiting T cell receptor (TCR) signaling. When compared with ZEA, DON was found to have a greater impact on many related indicators. Surprisingly, the combined effects of ZEA and DON did not appear to enhance toxicity compared to treatment with the individual mycotoxins. Our findings more clearly revealed that exposure to low-dose ZEA and DON caused immunosuppression in the body by mechanisms including inhibition of CD4+ T cells activation and reduction of Th1 cell differentiation, thus exacerbating infection of animals by Listeria monocytogenes.


Assuntos
Listeria monocytogenes , Zearalenona , Animais , Linfócitos T CD4-Positivos , Diferenciação Celular , Imunidade Celular , Camundongos , Linfócitos T , Tricotecenos
8.
Cell Biol Toxicol ; 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34308505

RESUMO

Mitochondrial-associated endoplasmic reticulum (ER) membranes (MAMs) play a key role in several physiological functions, including calcium ion (Ca2+) transfer and autophagy; however, the molecular mechanism controlling this interaction in cadmium (Cd)-induced neurotoxicity is unknown. This study shows that Cd induces alterations in MAMs and mitochondrial Ca2+ levels in PC12 cells and primary neurons. Ablation or silencing of mitofusin 2 (Mfn2) in PC12 cells or primary neurons blocks the colocalization of ER and mitochondria while reducing the efficiency of mitochondrial Ca2+ uptake. Moreover, Mfn2 defects reduce interactions or colocalization between GRP75 and VDAC1. Interestingly, the enhancement of autophagic protein levels, colocalization of LC3 and Lamp2, and GFP-LC3 puncta induced by Cd decreased in Mfn2-/- or Grp75-/- PC12 cells and Mfn2- or Grp75-silenced primary neurons. Notably, the specific Ca2+ uniporter inhibitor RuR blocked both mitochondrial Ca2+ uptake and autophagy induced by Cd. Finally, this study proves that the mechanism by which IP3R-Grp75-VDAC1 tethers in MAMs is associated with the regulation of autophagy by Mfn2 and involves their role in mediating mitochondrial Ca2+ uptake from ER stores. These results give new evidence into the organelle metabolic process by demonstrating that Ca2+ transport between ER-mitochondria is important in autophagosome formation in Cd-induced neurodegeneration.

9.
Metallomics ; 13(7)2021 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-34185081

RESUMO

Cadmium (Cd) is a toxic metal and an environmental pollutant and can cause neurotoxicity by inducing apoptosis. Fas (CD95/Apo-1) is a cell-surface receptor that triggers apoptosis upon ligand binding, mediated through the mitochondrial apoptotic pathway. However, the role and regulatory mechanism of Fas in Cd-induced neuronal apoptosis remain understudied. Here, we demonstrate that activation of caspase-8 and the c-Jun N-terminal kinase (JNK) pathway are mechanisms underlying Cd-induced Fas-mediated activation of the mitochondrial apoptotic pathway in rat cerebral cortical neurons. In vitro, Cd induced apoptosis in primary cortical neurons by activating caspase-8, JNK, and the mitochondrial apoptotic pathway. Fas knockdown enhanced cell viability in the presence of Cd and inhibited apoptosis by blocking Cd-activated Fas, caspase-8, and JNK. Fas knockdown also inhibited the decrease of mitochondrial membrane potential, cleavage of caspase-9/3 and poly (ADP-ribose) polymerase 1, and impaired nuclear translocation of apoptosis-inducing factor and endonuclease G. In vivo, Fas knockdown alleviated Cd-induced neuronal injury and inhibited apoptosis, activation of caspase-8, JNK, and mitochondrial apoptotic pathways in rat cerebral cortical neurons. In summary, our results demonstrate that Cd-activated Fas relays apoptotic signals from the cell surface to the mitochondria via caspase-8 and JNK activation in rat cerebral cortical neurons, leading to aggravation of the neuronal injury.

10.
Animals (Basel) ; 11(6)2021 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-34072384

RESUMO

Cadmium (Cd) is a type of noxious heavy metal that is distributed widely. It can severely injure the hepatocytes and cause liver dysfunction by inducing oxidative stress and mitochondrial damage. We evaluated the protective effects of α-lipoic acid (α-LA) or chlorogenic acid (CGA) and their combination on counteracting cadmium toxicity in vivo in three-yellow chickens. For three months, CdCl2 (50 mg/L) was administrated through their drinking water, α-LA (400 mg/kg) was added to feed and CGA (45 mg/kg) was employed by gavage. The administration of Cd led to variations in growth performance, biochemical markers (of the liver, kidney and heart), hematological parameters, liver histopathology (which suggested hepatic injury) and ultrastructure of hepatocytes. Some antioxidant enzymes and oxidative stress parameters showed significant differences in the Cd-exposure group when compared with the control group. The groups treated with Cd and administrated α-LA or CGA showed significant amelioration with inhibited mitochondrial pathway-induced apoptosis. Combining both drugs was the most effective in reducing Cd toxicity in the liver. In summary, the results demonstrated that α-LA and CGA may be beneficial in alleviating oxidative stress induced by oxygen free radicals and tissue injury resulting from Cd-triggered hepatotoxicity.

11.
Front Pharmacol ; 12: 632825, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33935722

RESUMO

Autophagic dysfunction is one of the main mechanisms by which the environmental pollutant cadmium (Cd) induces cell injury. Puerarin (Pue, a monomeric Chinese herbal medicine extract) has been reported to alleviate Cd-induced cell injury by regulating autophagy pathways; however, its detailed mechanisms are unclear. In the present study, to investigate the detailed mechanisms by which Pue targets autophagy to alleviate Cd hepatotoxicity, alpha mouse liver 12 (AML12) cells were used to construct a model of Cd-induced hepatocyte injury in vitro. First, the protective effect of Pue on Cd-induced cell injury was confirmed by changes in cell proliferation, cell morphology, and cell ultrastructure. Next, we found that Pue activated autophagy and mitigated Cd-induced autophagy blockade. In this process, the lysosome was further activated and the lysosomal degradation capacity was strengthened. We also found that Pue restored the autophagosome-lysosome fusion and the expression of Rab7 in Cd-exposed hepatocytes. However, the fusion of autophagosomes with lysosomes and autophagic flux were inhibited after knocking down Rab7, and were further inhibited after combined treatment with Cd. In addition, after knocking down Rab7, the protective effects of Pue on restoring autophagosome-lysosome fusion and alleviating autophagy blockade in Cd-exposed cells were inhibited. In conclusion, Pue-mediated alleviation of Cd-induced hepatocyte injury was related to the activation of autophagy and the alleviation of autophagy blockade. Pue also restored the fusion of autophagosomes and lysosomes by restoring the protein expression of Rab7, thereby alleviating Cd-induced autophagy blockade in hepatocytes.

12.
Ecotoxicol Environ Saf ; 220: 112367, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34052758

RESUMO

Zearalenone, which is ubiquitous in grains and animal feed, is a mycotoxin that can cause serious damage to animals and humans. Sertoli cells (SCs) can be used to study ZEA male reproductive toxicity in vitro. SCs provide energy for germ cells, where AMPK regulates intracellular energy. In order to explore the regulatory effect of AMPK on ZEA-induced lactate decline, we activated AMPK by AICAR and then inhibited AMPK by Compound C with ZEA-treated SCs for 24 h to detect intracellular lactate production-related indicators. Cell viability in the presence of 20 µmol/L ZEA and either 50 µmol/L AICAR or 5 µmol/L Compound C, respectively, did not damage SCs, and could effectively either activate or inhibit AMPK. Inhibition of AMPK promoted the production of pyruvate and lactate via increased expression of the glycolysis-related genes Pgam1 and the lactate production-related proteins GLUT1, LDHA, and MCT4. Activating AMPK inhibited the production of lactate and pyruvate by suppressing the expression of glycolysis-related genes HK1, Pgam1, and Gpi1 and that of lactate production-related proteins LDHA and MCT4. Zearalenone destroys the energy balance in SCs, activates P-AMPK, which inhibit the production of lactate and pyruvate in SCs. This also leads to the decrease of energy supply of SCs to spermatogenic cells, damages to reproductive system.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Estrogênios não Esteroides/toxicidade , Ácido Láctico/metabolismo , Células de Sertoli/efeitos dos fármacos , Zearalenona/toxicidade , Animais , Metabolismo Energético/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Glicólise/genética , Masculino , Ácido Pirúvico/metabolismo , Ratos , Células de Sertoli/metabolismo
14.
Front Vet Sci ; 8: 637369, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33644155

RESUMO

Cadmium (Cd) can causes osteoporosis and joint swelling. However, the mechanism of Cd toxicity in chondrocytes and how to alleviate Cd poisoning to chondrocytes are still unclear. Herein, we evaluated the toxicity of Cd to chicken chondrocytes, and whether vitamin D can relieve the toxicity of Cd to chondrocytes. Primary chondrocytes were collected from knee-joint cartilage of 15-day-old chicken embryos. They were treated with (0, 1, 2, and 4) µM Cd alone, 10-8 M 1α,25-(OH)2D3 alone, or 2 µM Cd combined with 10-8 M 1α,25-(OH)2D3. We found that Cd significantly inhibited Sox9 and ACAN mRNA expression, which are markers for chondrocyte differentiation, downregulated the mitochondrial membrane potential, upregulated the Bax/B-cell lymphoma 2 ratio. Furthermore, Cd significantly promoted matrix metalloproteinase (MMP)-9 expression, thus accelerating the degradation of extracellular matrix. And Cd also inhibited the expression of main macromolecular protein of extracellular matrix, Collagen type IIα1 (COL2A1) and acid mucopolysaccharide. However, 1α,25-(OH)2D3 pretreatment significantly alleviated the toxicity effects of Cd on the differentiation, apoptosis and extracellular matrix gene expression in primary chondrocytes. Conclusively, Cd exposure could inhibited chicken embryo chondrocytes differentiation, extracellular matrix gene expression, and induced chondrocyte apoptosis. However, these toxic effects of Cd are alleviated by the pretreatment of chondrocytes with 1α,25-(OH)2D3.

15.
Toxicol Appl Pharmacol ; 415: 115441, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33556388

RESUMO

The immunotoxicity of zearalenone (ZEA) and deoxynivalenol (DON), two of the most common environmental mycotoxins, has been well investigated. However, due to the complexity of the immune system, especially during bacterial infection, many types of immune cells are involved in invasion resistance and bacterial clearance. Of these, T helper 2 (Th2) cells, which are members of the helper T cell family, assist B cells to activate and differentiate into antibody-secreting cells, participate in humoral immune response, and, ultimately, eliminate pathogens. Thus, it is important to identify the stage at which these toxins affect the immune function, and to clarity the underlying mechanisms. In this study, mice infected with Listeria monocytogenes (Listeria) were used to study the effects of ZEA, DON, and ZEA + DON on Th2 differentiation, Interleukin-4 Receptor (IL-4R) expression, costimulatory molecules expression and cytokine secretion after Listeria infection. Naive CD4+ T cells, isolated from mice, were used to verify the in vivo effects and the associated mechanisms. In vivo experiments showed that these toxins aggravated spleen damage after Listeria infection and reduced the differentiation of Th2 cells by affecting the synthesis of IL-4R of CD4+ T cells. In addition, the level of the costimulatory molecule CD154 decreased. Consistent with this, in vitro studies showed that these toxins inhibited the differentiation of mouse naive CD4+ T cell into Th2 subtype and decreased IL-4R levels. In addition, the levels of costimulatory molecules CD154, CD278 and the Th2 cells secrete cytokines IL-4, IL-6, and IL-10 decreased. Based on our in vivo and in vitro experiments, we suggest that ZEA, DON, and ZEA + DON inhibit the expression of costimulatory molecules on CD4+ T cell, and inhibit the IL-4R-mediated Th2 cell differentiation. This may indicate that the body cannot normally resist or clear the pathogen after mycotoxin poisoning.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Listeria monocytogenes/patogenicidade , Listeriose/induzido quimicamente , Ativação Linfocitária/efeitos dos fármacos , Receptores de Interleucina-4/metabolismo , Baço/efeitos dos fármacos , Células Th2/efeitos dos fármacos , Tricotecenos/toxicidade , Zearalenona/toxicidade , Animais , Ligante de CD40/metabolismo , Células Cultivadas , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Interações Hospedeiro-Patógeno , Proteína Coestimuladora de Linfócitos T Induzíveis/metabolismo , Listeria monocytogenes/imunologia , Listeriose/imunologia , Listeriose/metabolismo , Listeriose/microbiologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Transdução de Sinais , Baço/imunologia , Baço/metabolismo , Baço/microbiologia , Células Th2/imunologia , Células Th2/metabolismo , Células Th2/microbiologia
16.
J Cell Mol Med ; 25(2): 937-945, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33277741

RESUMO

Osteoclastogenesis requires the involvement of transcription factors and degrading enzymes, and is regulated by upstream and downstream signalling. However, c-Fos how regulates osteoclastogenesis through autophagy remain unclear. This study aimed to explore the role of c-Fos during osteoprotegerin (OPG)-mediated suppression of osteoclastogenesis. We found that the number of osteoclasts and the expression of c-Fos, MMP-9, CAⅡ, Src and p62 were decreased after treated with OPG, including attenuation the PI3K/Akt and the TAK1/S6 signalling pathways, but the expression of Beclin1 and LC3Ⅱ were increased. Knockdown of Beclin1 could reverse the expression of c-Fos and MMP-9 by activating the PI3K/Akt signalling pathway, but inhibiting the autophagy and the TAK1/S6 signalling pathway. In addition, inhibition of autophagy using the PI3K inhibitor LY294002 did not rescues OPG-mediated suppression of osteoclastogenesis, but caused reduction of the expression of c-Fos and CAⅡ by attenuating the autophagy, as well as the PI3K/Akt and the TAK1/S6 signalling pathways. Furthermore, continuous activation of c-Fos could reverse OPG-mediated suppression of osteoclastogenesis by activating the autophagy and the PI3K/Akt and the TAK1/S6 signalling pathways. Thus, overexpression of c-Fos could reverse OPG-mediated suppression of osteoclastogenesis via activation of Beclin1-induced autophagy, indicating c-Fos might serve as a new candidate for bone-related basic studies.

17.
J Hazard Mater ; 405: 124251, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33168313

RESUMO

Cadmium (Cd), an environmental pollutant, induces osteoporosis by directly destroying bone tissue, but its direct damaging effect on bone cells is not fully illustrated. Here, we treated mouse bone marrow stem cells (BMSC) and bone marrow macrophages (BMM) with Cd, and gave BALB/c mice Cd in water. Long-term Cd exposure significantly inhibited BMSC osteogenesis and osteoclast differentiation in vitro, and induced osteoporosis in vivo. Cd exposure also reduced P2X7 expression dramatically. However, P2X7 deletion significantly inhibited osteoblast and osteoclast differentiation; P2X7 overexpression obviously reduced the suppression effect of Cd on osteoblast and osteoclast differentiation. The suppression of P2X7-PI3K-AKT signaling aggravated the effect of Cd. In mice, short-term Cd exposure did not result in osteoporosis, but bone formation was inhibited, RANKL expression was increased, and osteoclasts were significantly increased in vivo. In vitro, short-term Cd exposure not only increased osteoclast numbers, but also promoted osteoclast adhesion function at late-stage osteoclast differentiation. Cd exposure also reduced P2X7 expression in vivo and in vitro. Our results demonstrate that short-term Cd exposure does not affect osteoblast and osteoclast apoptosis in vivo and in vitro, but long-term Cd exposure significantly increases bone tissue apoptosis. Overall, our results describe a novel mechanism for Cd-induced osteoporosis.


Assuntos
Cádmio , Osteoporose , Animais , Cádmio/toxicidade , Diferenciação Celular , Células Cultivadas , Camundongos , Camundongos Endogâmicos BALB C , Osteoclastos , Osteoporose/induzido quimicamente , Fosfatidilinositol 3-Quinases
18.
Sci Total Environ ; 750: 141638, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32858297

RESUMO

Cadmium is a common environmental pollutant that accumulates in the bone and kidneys and causes severe health and social problems. However, the effects of Cd on the occurrence of osteoporosis and its mechanism of action in this process are unclear. To test whether Cd-induced osteoporosis is mediated via P2X7/PI3K/AKT signaling, duck bone marrow mesenchymal stem cells (BMSCs) and bone marrow macrophage cells (BMMs) were treated with Cd for 5 days, and duck embryos were treated with Cd. Micro-CT analysis indicated that Cd-induced osteoporosis occurs in vivo, and histopathology and immunohistochemical analyses also revealed that Cd induced bone damage and the downregulation of osteogenic and bone resorption-related proteins. Cd exposure significantly inhibited the differentiation of BMSCs and BMMs into osteoblasts and osteoclasts in vitro, and promoted osteoblast and osteoclast apoptosis. Cd exposure significantly downregulated the P2X7/PI3K/AKT signaling pathway in vivo and in vitro, and inhibition of this signaling pathway significantly aggravated osteoblast and osteoclast differentiation. Cd exposure also upregulated the OPG/RANKL ratio in vivo and in vitro, further inhibiting osteoclast differentiation. These results demonstrate that Cd causes osteoporosis in duck by inhibiting P2X7/PI3K/AKT signaling and increasing the OPG/RANKL ratio. These results establish a previously unknown mechanism of Cd-induced osteoporosis.


Assuntos
Osteoclastos , Osteoporose , Animais , Cádmio/toxicidade , Diferenciação Celular , Patos , Osteoblastos , Osteoporose/induzido quimicamente , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt
19.
Cell Cycle ; 19(23): 3386-3397, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33222613

RESUMO

Heavy metal pollution is a problem that cannot be ignored. Due to the prevalence of cadmium in the environment and its harmful effects on humans, cadmium pollution has become a research hotspot recently. The mechanism of cadmium-induced toxicity has also drawn much attention and most studies have been conducted using whole cells, but the toxicological mechanism of cadmium remains unclear. In this study, we aimed to obtain NRK-52E cells at different growth stages by various methods and analyze the differences in cadmium toxicity. The results show that the cadmium sensitivity of cells in each phase was different and the late apoptotic rate was increased significantly after 5 µM Cd treatment. In addition, cadmium easily induces apoptosis of G0- and S-phase cells, as well as necrosis of S- and M-phase cells, but has no significant effect on G1-phase cells. Overall, we first explored the differences in the effects of cadmium on NRK-52E cells at various growth phases. Besides, the findings of this study might provide a theoretical basis for further exploration of the toxicological mechanism of cadmium.Abbreviations Cd: cadmium; CDK: cyclin-dependent kinases; DAPI 2-(4-amidinophenyl)-1H-indole-6-carboxamidine; TBST: Tris-buffered saline with Tween-20; PI: propidium iodide; DMEM: Dulbecco's Modified Eagle Medium; BCA: bicinchoninic acid.

20.
Toxicology ; 446: 152611, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33031904

RESUMO

Cadmium (Cd), a heavy metal produced by various industries, contaminates the environment and seriously damages the skeletal system of humans and animals. Recent studies have reported that Cd can affect the viability of cells, including osteoblasts, both in vivo and in vitro. However, the mechanism of Cd-induced apoptosis remains unclear. In the present study, primary rat osteoblasts were used to investigate the Cd-induced apoptotic mechanism. We found that treatment with 2 and 5 µM Cd for 12 h decreased osteoblast viability and increased apoptosis. Furthermore, Cd increased the generation of reactive oxygen species (ROS), and, thus, DNA damage measured via p-H2AX. The level of the nuclear transcription factor p53 was significantly increased, which upregulated the expression of PUMA, Noxa, Bax, and mitochondrial cytochrome c, downregulated the expression of Bcl-2, and increased the level of cleaved caspase-3. However, pretreatment with the ROS scavenger N-acetyl-l-cysteine (NAC) or the p53 transcription specific inhibitor PFT-α suppressed Cd-induced apoptosis. Our results indicate that Cd can induce apoptosis in osteoblasts by increasing the generation of ROS and activating the mitochondrial p53 signaling pathway, and this mechanism requires the transcriptional activation of p53.


Assuntos
Apoptose/efeitos dos fármacos , Cádmio/toxicidade , Mitocôndrias/metabolismo , Osteoblastos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/fisiologia , Células Cultivadas , Mitocôndrias/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
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