Publications by authors named "Ruilong Song"

36 Publications

Role of mitochondrial dysfunction and PINK1/Parkin-mediated mitophagy in Cd-induced hepatic lipid accumulation in chicken embryos.

Life Sci 2021 Nov 1;284:119906. Epub 2021 Sep 1.

Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu 225009, PR China; College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu 225009, PR China. Electronic address:

The present study was performed to investigate the effects of Cd exposure on lipid metabolism and mitochondrial dysfunction and to explore the role of mitophagy in Cd-induced dysregulation of lipid metabolism in chicken embryo liver tissues and hepatocytes. To this end, seven-day-old chicken embryos were exposed to different concentrations of Cd for 7 days, and primary chicken embryo hepatocytes were treated with Cd at four different concentrations for 6 h. Furthermore, the mitophagy inhibitor cyclosporine A (CsA) was used to investigate the role of mitophagy in Cd-induced disruption of lipid metabolism. Lipid accumulation, the expression levels of genes involved in lipid metabolism, mitochondrial dysfunction, and mitophagy were measured. The results demonstrated that Cd exposure increases hepatic triglyceride (TG) accumulation and the expression levels of lipogenic genes while decreasing those of lipolytic genes. Furthermore, Cd exposure was observed to alter mitochondrial morphology in terms of reduced size, excessive mitochondrial damage, and the formation of mitophagosomes. The co-localization of lysosome-associated membrane glycoprotein 2 and LC3 puncta was significantly increased in primary chicken embryo hepatocytes after Cd exposure. Moreover, Cd exposure increased LC3, PINK1, and Parkin protein expression levels. CsA effectively alleviated Cd-induced mitochondrial dysfunction, blocked mitochondrial membrane potential collapse, and suppressed PINK1/Parkin-mediated mitophagy. Furthermore, CsA treatment reversed the Cd-induced TG accumulation in liver tissues but further increased it in hepatocytes. Taken together, our findings demonstrate (for the first time) the importance of mitochondrial dysfunction and mitophagy via the PINK1/Parkin pathway in Cd-induced disruption of lipid metabolism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.lfs.2021.119906DOI Listing
November 2021

Beclin 1 positively regulates osteoprotegerin-induced inhibition of osteoclastogenesis by increasing autophagy in vitro.

Differentiation 2021 Sep-Oct;121:35-43. Epub 2021 Aug 23.

Institutes of Agricultural Science and Technology Development, Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, 225009, Jiangsu, PR China; College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, Jiangsu, PR China; Jiangsu Key Laboratory of Zoonosis, Yangzhou, 225009, Jiangsu, PR China. Electronic address:

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.diff.2021.08.003DOI Listing
August 2021

The epigenetic regulator BRD4 is involved in cadmium-triggered inflammatory response in rat kidney.

Ecotoxicol Environ Saf 2021 Aug 13;224:112620. Epub 2021 Aug 13.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, PR China; Jiangsu Key Laboratory of Zoonosis, Yangzhou, PR China. Electronic address:

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ecoenv.2021.112620DOI Listing
August 2021

Puerarin Attenuates Cadmium-Induced Neuronal Injury via Stimulating Cadmium Excretion, Inhibiting Oxidative Stress and Apoptosis.

Biomolecules 2021 07 2;11(7). Epub 2021 Jul 2.

College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/biom11070978DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8301907PMC
July 2021

Ca transfer via the ER-mitochondria tethering complex in neuronal cells contribute to cadmium-induced autophagy.

Cell Biol Toxicol 2021 Jul 26. Epub 2021 Jul 26.

College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China.

Mitochondrial-associated endoplasmic reticulum (ER) membranes (MAMs) play a key role in several physiological functions, including calcium ion (Ca) 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 Ca 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 Ca 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 Ca uniporter inhibitor RuR blocked both mitochondrial Ca 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 Ca uptake from ER stores. These results give new evidence into the organelle metabolic process by demonstrating that Ca transport between ER-mitochondria is important in autophagosome formation in Cd-induced neurodegeneration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10565-021-09623-yDOI Listing
July 2021

Induction of mitochondrial apoptosis pathway mediated through caspase-8 and c-Jun N-terminal kinase by cadmium-activated Fas in rat cortical neurons.

Metallomics 2021 07;13(7)

College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/mtomcs/mfab042DOI Listing
July 2021

Cadmium exposure induces rat proximal tubular cells injury via p62-dependent Nrf2 nucleus translocation mediated activation of AMPK/AKT/mTOR pathway.

Ecotoxicol Environ Saf 2021 May 11;214:112058. Epub 2021 Mar 11.

College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road, Yangzhou 225009, People's Republic of China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou 225009, People's Republic of China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, People's Republic of China. Electronic address:

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a nuclear transcription factor of great concern which is widely involved in physiological and pathological processes of the organism, but the role and regulatory mechanism of Nrf2 in kidney exposed to cadmium (Cd) remain largely unknown. Here we demonstrated that Cd exposure induced injury in primary rat proximal tubular (rPT) cells and NRK-52E cell line, which was accompanied by autophagic flux blockade and subsequent accumulation of p62. Cd-activated nucleus translocation of Nrf2 depended on p62, which promoted antioxidant genes transcription, but it failed to against Cd-induced cell injury and ultimately succumbed to Cd toxicity. CDDO Methyl Ester (CDDO-ME) or ML385 treatment aggravated or alleviated rPT cells injury induced by Cd respectively, indicating that Nrf2 nucleus translocation played a negative role during Cd-induced rPT cells injury. Phosphorylation of 5' AMP-activated protein kinase (AMPK) decreased together with enhanced Nrf2 nucleus translocation in rPT cells exposed to Cd. Dephosphorylation of AMPK induced by Cd were facilitated or restored by CDDO-ME or ML385 treatment, which confirmed AMPK is a downstream factor of Nrf2. Simultaneously, CDDO-ME further enhanced Phosphorylation of mTOR and AKT which increased during Cd exposure. While, Cd-induced phosphorylation of mTOR and AKT were reversed by ML385 treatment. These results illustrated that Cd mediated Nrf2 nucleus translocation depends on p62 accumulation which results from autophagic flux inhibition. The enhanced nucleus translocation of Nrf2 suppresses phosphorylation of AMPK to inactivate AKT/mTOR signaling, and results in rPT cells injury finally.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ecoenv.2021.112058DOI Listing
May 2021

Corrigendum to "TGF-β-activated kinase 1 (TAK1) mediates cadmium-induced autophagy in osteoblasts via the AMPK / mTORC1 / ULK1 pathway" [Toxicology 442 (2020) 152538].

Toxicology 2021 Apr 2;453:152738. Epub 2021 Mar 2.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, PR China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, PR China. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tox.2021.152738DOI Listing
April 2021

Puerarin prevents cadmium-induced disorder of testicular lactic acid metabolism in rats by activating 5' AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) signaling pathway.

Environ Toxicol 2021 May 6;36(5):945-957. Epub 2021 Jan 6.

College of Veterinary Medicine, Yangzhou University, Yangzhou, China.

Cadmium (Cd) interferes with the function of the male reproductive system; however, the molecular mechanism is poorly understood. This study aimed to evaluate the effect of puerarin (PU) on Cd-induced testicular lactic acid metabolism disorder. Weaning male Sprague-Dawley rats were pre-fed for 7 days, weighed, and randomly divided into four groups: Control group, CdAc group, CdAc  + PU group, PU group. The results showed that Cd accumulated in the testis, the testicles became congested and shrank, and the testis index decreased in the rats treated in the CdAc group. Cadmium exposure reduced the serum concentration of testosterone, and the concentration of lactic acid and pyruvate in the testis. Cd decreased testicular superoxide dismutase activity and total antioxidant capacity, and increased testicular malondialdehyde levels. Cd reduced the level of ATP, glycolytic gene expression, and lactate production-related proteins in the testis. Cd also decreased the expression of 5' AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) signaling pathway-related proteins in the testis. However, these negative effects were attenuated by PU administration. In summary, Cd reduces the production of lactic acid in the testis of rats, while PU administration restores the production of lactic acid and reduces the toxicity of Cd to the testis of rats.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/tox.23096DOI Listing
May 2021

Overexpression of c-Fos reverses osteoprotegerin-mediated suppression of osteoclastogenesis by increasing the Beclin1-induced autophagy.

J Cell Mol Med 2021 01 4;25(2):937-945. Epub 2020 Dec 4.

Institutes of Agricultural Science and Technology Development, Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, China.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcmm.16152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7812271PMC
January 2021

The effect of P2X7 on cadmium-induced osteoporosis in mice.

J Hazard Mater 2021 03 26;405:124251. Epub 2020 Oct 26.

College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009 Jiangsu, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009 Jiangsu, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, 225009 Jiangsu, PR China. Electronic address:

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2020.124251DOI Listing
March 2021

Cadmium induces apoptosis via generating reactive oxygen species to activate mitochondrial p53 pathway in primary rat osteoblasts.

Toxicology 2020 12 6;446:152611. Epub 2020 Oct 6.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, PR China. Electronic address:

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tox.2020.152611DOI Listing
December 2020

Cadmium exposure triggers osteoporosis in duck via P2X7/PI3K/AKT-mediated osteoblast and osteoclast differentiation.

Sci Total Environ 2021 Jan 15;750:141638. Epub 2020 Aug 15.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu 225009, PR China. Electronic address:

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2020.141638DOI Listing
January 2021

p53 positively regulates osteoprotegerin-mediated inhibition of osteoclastogenesis by downregulating TSC2-induced autophagy in vitro.

Differentiation 2020 Jul - Aug;114:58-66. Epub 2020 Jun 21.

College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, Jiangsu, PR China; Jiangsu Key Laboratory of Zoonosis, Yangzhou, 225009, Jiangsu, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, Jiangsu, PR China. Electronic address:

Osteoclasts are terminally multinucleated cells that are regulated by nuclear factor-activated T cells c1 (NFATc1), and are responsible for bone resorption while the tartrate resistant acid phosphatase (TRAP) enzymes releases into bone resorption lacunae. Furthermore, tumor suppressor p53 is a negative regulator during osteoclastogenesis. Osteoprotegerin (OPG) inhibits osteoclastogenesis and bone resorption by activating autophagy, however, whether p53 is involved in OPG-mediated inhibition of osteoclastogenesis remains unclear. In the current study, OPG could enhance the expression of p53 and tuberin sclerosis complex 2 (TSC2). Moreover, the expression of p53 is regulated by autophagy during OPG-mediated inhibition of osteoclastogenesis. Inhibition of p53 by treated with pifithrin-α (PFTα) causing augments of osteoclastogenesis and bone resorption, also reversed OPG-mediated inhibition of osteoclastogenesis by reducing the expression of TSC2. In addition, knockdown of TSC2 using siRNA could rescue OPG-mediated inhibition of osteoclastogenesis by reducing autophagy, which is manifested by the decrease of the expression of Beclin1 and the phosphorylation of mammalian target of rapamycin (mTOR) and ribosomal protein S6 kinase beta 1 (S6K1, also known as p70S6K). Collectively, p53 plays a critical role during OPG-mediated inhibition of osteoclastogenesis via regulating the TSC2-induced autophagy in vitro.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.diff.2020.06.002DOI Listing
July 2021

TGF-β-activated kinase 1 (TAK1) mediates cadmium-induced autophagy in osteoblasts via the AMPK / mTORC1 / ULK1 pathway.

Toxicology 2020 09 18;442:152538. Epub 2020 Jul 18.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, PR China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, PR China. Electronic address:

Cadmium (Cd) is one of worldwide environmental pollutants that causes bone homeostasis, which depends on the resorption of bones by osteoclasts and formation of bones by the osteoblasts (OB). However, the Cd toxicity on OB and its mechanism are unclear. Autophagy is an evolutionarily conserved degradation process in which domestic intracellular components are selectively digested for the recycling of nutrients and energy. This process is indispensable for cell homeostasis maintenance and stress responses. Dysregulation at the level of autophagic activity consequently disturbs the balance between bone formation and bone resorption and mediates the onset and progression of multiple bone diseases, including osteoporosis. TAK1 has been recently emerged as an activator of AMPK and hence an autophagy inducer. AMPK is a key molecule that induces autophagy and regulates cellular metabolism to maintain energy homeostasis. Conversely, autophagy is inhibited by mTORC1. In this study, we found that Cd treatment caused the formation of autophagosomes, LC3-II lipidation and p62 downregulation, and the increased autophagic flux, indicating that Cd treatment induced autophagy in OBs. Cd treatment induced TAK1 activation mediated AMPK phosphorylation, which promoted autophagy via phosphorylation of ULK1 at S317. Meanwhile, Cd treatment dramatically decreased mTORC1, S6K1, 4E-BP1, S6, ULK1 and ULK1 phosphorylation, suggesting that mTORC1 activity was inhibited and inactive mTORC1 prevents ULK1 activation by phosphorylating ULK1 at SerS555 and Ser757. Our data strongly suggest that TAK1 mediates AMPK activation, which activates ULK1 by phosphorylating ULK1 and suppressing mTORC1-mediated ULK1 and ULK1 phosphorylation. Our study has revealed a signaling mechanism for TAK1 in Cd-induced autophagy in OBs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tox.2020.152538DOI Listing
September 2020

Role of calcium-sensing receptor in cadmium-induced apoptosis of rat primary osteoblasts in vitro.

Toxicol In Vitro 2020 Sep 27;67:104923. Epub 2020 Jun 27.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, PR China. Electronic address:

Calcium is essential to various physiological and pathophysiological cellular processes. Calcium-sensing receptor (CasR), a seven-transmembrane-spanning protein that responds to changes in extracellular Ca, partly modulates calcium homeostasis, thereby influencing bone metabolism. In this study, we aimed to elucidate the role of CasR in Cd-induced calcium homeostasis disruption and OB apoptosis, and the underlying mechanisms. Cd treatment dramatically increased the protein expression of CasR and elevated the intracellular calcium concentration. Meanwhile, OBs apoptosis rate and caspase-dependent apoptosis protein levels, including cleaved caspase 3, cleaved caspase 9 and the ratio of Bax/Bcl-2 were increased. However, downregulation of CasR by CasR siRNA effectively suppressed the effects of Cd on theses phenomena. At the same time, we illustrated that CasR siRNA pretreatment blocked Cd-inhibited the phosphorylation of PKC and decreased Cd-induced the phosphorylation of PI3K/AKT. Our results suggested that CasR-mediated PKC and PI3K/AKT signaling pathways involve in calcium oscillation and apoptosis in OB caused by Cd maybe responsible for the bone homeostasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tiv.2020.104923DOI Listing
September 2020

Author Correction: Zearalenone altered the cytoskeletal structure via ER stress- autophagy- oxidative stress pathway in mouse TM4 Sertoli cells.

Sci Rep 2020 Jun 25;10(1):10658. Epub 2020 Jun 25.

College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, China.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-67552-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7314833PMC
June 2020

Effect of cadmium on osteoclast differentiation during bone injury in female mice.

Environ Toxicol 2020 Apr 3;35(4):487-494. Epub 2019 Dec 3.

College of Veterinary Medicine, Yangzhou University, Yangzhou, China.

Cadmium (Cd) is a toxic heavy metal that represents an occupational hazard and environmental pollutant toxic heavy metal, which can cause osteoporosis following accumulation in the body. The purpose of this study was to investigate the effect of Cd on bone tissue osteoclast differentiation in vivo. Female BALB/c mice were randomly divided into three groups and given drinking water with various concentrations of Cd (0, 5, and 25 mg/L) for 16 weeks, after which the mice were sacrificed after collecting urine and blood. The level of Cd, calcium (Ca), phosphorus (P), trace elements, and some biochemical indicators were measured, and the bone was fixed in a 4% formaldehyde solution for histological observation. Bone marrow cells were isolated to determine the expression of osteoclast-associated mRNA and proteins. Cd was increased in the blood, urine, and bone in response to Cd in drinking water in a dose-dependent manner. The content of iron (Fe), manganese (Mn), and zinc (Zn) was significantly increased, whereas Ca and P were decreased in bone compared to the control group. Cd affected the histological structure of the bone, and induced the upregulation and downregulation of tartrate-resistant acid phosphatase 5b (TRACP-5b) and estradiol in the serum, respectively. Cd had no significant effect on the alkaline phosphatase activity in the serum. The expression of osteoclast marker proteins, including TRACP, cathepsin K, matrix metalloprotein 9, and carbonic anhydrases were all increased in the Cd-treated bone marrow cells. Cd significantly increased the expression of receptor activator of nuclear factor kappa B ligand (RANKL), but had lower effect on the expression of osteoprotegerin (OPG) in both bone marrow cells and bone tissue. Thus, Cd exposure destroyed the bone microstructure, promoted the formation of osteoclasts in the bone tissue, and accelerated bone resorption, in which the OPG/RANKL pathway may play an important role.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/tox.22884DOI Listing
April 2020

Suppression of AMP-activated protein kinase reverses osteoprotegerin-induced inhibition of osteoclast differentiation by reducing autophagy.

Cell Prolif 2020 Jan 7;53(1):e12714. Epub 2019 Nov 7.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China.

Objectives: Osteoclasts (OC) are unique terminally differentiated cells whose primary function is bone resorption. We previously showed that osteoprotegerin (OPG) inhibits OC differentiation in vitro by enhancing autophagy via the adenosine monophosphate-activated protein kinase (AMPK)/mTOR/p70S6K signalling pathway in vitro. Here, we aimed to elucidate the mechanism of AMPK mediated autophagy to regulate OPG-mediated inhibition of OC differentiation and identify potential therapeutic targets associated with bone loss.

Materials And Methods: We used the AMPK activator AICAR to determine the relationship between AMPK activation and OC differentiation, and studied the role of AMPK-mediated autophagy in OPG-mediated inhibition of OC differentiation by using autophagy inhibitors or AMPK knockdown.

Results: AMP-activated protein kinase activation caused LC3II accumulation and weakened OC differentiation activity. In contrast, inactivation of autophagy by 3-methyladenine or Bafilomycin A1 could attenuate OPG-mediated inhibition of OC differentiation via the AMPK/mTOR/p70S6K signalling pathway. Furthermore, the AMPK inhibitor compound C and knockdown of AMPK impaired OPG-mediated inhibition of OC differentiation by inducing autophagy.

Conclusions: These results demonstrated that the AMPK signalling pathway functions as a critical regulator in the OPG-mediated inhibition of OC differentiation, by inducing autophagy. Our results provide a basis for future bone-related studies on the AMPK signalling pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cpr.12714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985670PMC
January 2020

A hybrid sub-lineage of Listeria monocytogenes comprising hypervirulent isolates.

Nat Commun 2019 09 30;10(1):4283. Epub 2019 Sep 30.

Jiangsu Key Laboratory of Zoonosis, Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Yangzhou University, 48 East Wenhui Road, Yangzhou, 225009, Jiangsu Province, China.

The foodborne pathogen Listeria monocytogenes (Lm) is a highly heterogeneous species and currently comprises of 4 evolutionarily distinct lineages. Here, we characterize isolates from severe ovine listeriosis outbreaks that represent a hybrid sub-lineage of the major lineage II (HSL-II) and serotype 4h. HSL-II isolates are highly virulent and exhibit higher organ colonization capacities than well-characterized hypervirulent strains of Lm in an orogastric mouse infection model. The isolates harbour both the Lm Pathogenicity Island (LIPI)-1 and a truncated LIPI-2 locus, encoding sphingomyelinase (SmcL), a virulence factor required for invasion and bacterial translocation from the gut, and other non-contiguous chromosomal segments from another pathogenic species, L. ivanovii. HSL-II isolates exhibit a unique wall teichoic acid (WTA) structure essential for resistance to antimicrobial peptides, bacterial invasion and virulence. The discovery of isolates harbouring pan-species virulence genes of the genus Listeria warrants global efforts to identify further hypervirulent lineages of Lm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-019-12072-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6768887PMC
September 2019

Antiosteoclastic bone resorption activity of osteoprotegerin via enhanced AKT/mTOR/ULK1-mediated autophagic pathway.

J Cell Physiol 2020 03 18;235(3):3002-3012. Epub 2019 Sep 18.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China.

Autophagy plays a critical role in the maintenance of bone homeostasis. Osteoprotegerin (OPG) is an inhibitor of osteoclast-mediated bone resorption. However, whether autophagy is involved in the antiosteoclastogenic effects of OPG remains unclear. The present study aimed to investigate the potential mechanism of autophagy during OPG-induced bone resorption via inhibition of osteoclasts differentiated from bone marrow-derived macrophages in BALB/c mice. The results showed that after treatment with receptor activator of nuclear factor-κΒ ligand and macrophage colony-stimulating factor for 3 days, TRAP osteoclasts formed, representing the resting state of autophagy. These osteoclasts were treated with OPG and underwent autophagy, as demonstrated by LC3-II accumulation, acidic vesicular organelle formation, and the presence of autophagosomes. The levels of autophagy-related proteins, LC3-II increased and P62 decreased at 3 hr in OPG-treated osteoclasts. The viability, differentiation, and bone resorption activity of osteoclasts declined after OPG treatment. Treatment with OPG and chloroquine, an autophagy inhibitor, attenuated OPG-induced inhibition of osteoclastic bone resorption, whereas rapamycin (RAP), an autophagy inducer, enhanced OPG-induced inhibition of differentiation, survival, and bone resorption activity of osteoclasts. Furthermore, OPG reduced the amount of phosphorylated(p) protein kinase B (AKT) and pmTOR and increased the level of pULK, in a dose-dependant manner. LY294002, a phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/AKT pathway inhibitor, attenuated the decline in pAKT, but enhanced the decline in pmTOR and the increase in pULK1 following OPG treatment. RAP enhanced the OPG-induced increase in pULK1. The PI3K inhibitor 3-methyladenine partly blocked OPG-induced autophagy. Thus, the results revealed that OPG inhibits osteoclast bone resorption by inducing autophagy via the AKT/mTOR/ULK1 signaling pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jcp.29205DOI Listing
March 2020

The effect of P2X7R-mediated Ca signaling in OPG-induced osteoclasts adhesive structure damage.

Exp Cell Res 2019 10 12;383(2):111555. Epub 2019 Aug 12.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, 225009, PR China. Electronic address:

Osteoclast adhesion is important for bone resorption. Osteoprotegerin inhibits osteoclast differentiation and bone resorption via Ca signaling. Purinergic receptor P2X7 (P2X7R) affects osteoclastogenesis by activating transcription factor nuclear factor of activated T cells 1 (NFATc1). However, the detailed mechanism of osteoprotegerin-mediated P2X7R modulation of osteoclast adhesion is unclear. This study aimed to determine the effect of P2X7R on osteoprotegerin-induced damage to osteoclast adhesion. Osteoprotegerin reduced the expression of P2X7R, and protein tyrosine kinase 2 (PYK2) and SRC phosphorylation, and reduced calcium concentration, significantly decreasing Ca-NFATc1 signaling. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM)/N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) partly or absolutely recovered osteoprotegerin-induced osteoclasts adhesion structure damage, including increased the PYK2 and SRC phosphorylation, changed the distribution of PYK2/SRC and integrinαvβ3, and inhibited retraction of lamellipodia and filopodia and recovered osteoclast bone resorption activity. In addition, BAPTA-AM/W-7 also increased osteoprotegerin-induced activation of Ca-NFATc1 signaling, and restored normal P2X7R levels. P2X7R knockdown significantly inhibited osteoclast differentiation, and the formation of lamellipodia and filopodia, reduced the PYK2 and SRC phosphorylation, and inhibited Ca-related protein activation. However, P2X7R knockdown aggravated osteoprotegerin-induced osteoclast adhesion damage via Ca signaling. In conclusion, the P2X7R-Ca NFATc1 signaling pathway has a key functional role in osteoprotegerin-induced osteoclast adhesion structure damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.yexcr.2019.111555DOI Listing
October 2019

Osteoprotegerin inhibit osteoclast differentiation and bone resorption by enhancing autophagy via AMPK/mTOR/p70S6K signaling pathway in vitro.

J Cell Biochem 2018 Sep 6. Epub 2018 Sep 6.

College of Veterinary Medicine, Yangzhou University, Yangzhou, China.

Osteoclasts are highly differentiated terminal cells formed by fusion of hematopoietic stem cells. Previously, osteoprotegerin (OPG) inhibit osteoclast differentiation and bone resorption by blocking receptor activator of nuclear factor-κB ligand (RANKL) binding to RANK indirect mechanism. Furthermore, autophagy plays an important role during osteoclast differentiation and function. However, whether autophagy is involved in OPG-inhibited osteoclast formation and bone resorption is not known. To elucidate the role of autophagy in OPG-inhibited osteoclast differentiation and bone resorption, we used primary osteoclast derived from mice bone marrow monocytes/macrophages (BMM) by induced M-CSF and RANKL. The results showed that autophagy-related proteins expression were upregulated; tartrate-resistant acid phosphatase-positive osteoclast number and bone resorption activity were decreased; LC3 puncta and autophagosomes number were increased and activated AMPK/mTOR/p70S6K signaling pathway. In addition, chloroquine (as the autophagy/lysosome inhibitor, CQ) or rapamycin (as the autophagy/lysosome inhibitor, Rap) attenuated osteoclast differentiation and bone resorption activity by OPG treatment via AMPK/mTOR/p70S6K signaling pathway. Our data demonstrated that autophagy plays a critical role in OPG inhibiting osteoclast differentiation and bone resorption via AMPK/mTOR/p70S6K signaling pathway in vitro.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jcb.27468DOI Listing
September 2018

ERK1/2 MAPK promotes autophagy to suppress ER stress-mediated apoptosis induced by cadmium in rat proximal tubular cells.

Toxicol In Vitro 2018 Oct 2;52:60-69. Epub 2018 Jun 2.

College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road,Yangzhou 225009, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China; Jiangsu Key Laboratory of Zoonosis,Yangzhou, China. Electronic address:

Cadmium (Cd) is a toxic heavy metal and its toxic mechanism is not entirely clear. The goal of the present study was to investigate the toxic mechanism of Cd on rPT cells, and to elucidate the role of ERK1/2 signaling pathway in mediating the relationship between apoptosis and autophagy. We evaluated the cell morphology, cell cycle distribution, apoptosis rates, and the expression of related proteins. We observed that increased Cd concentration disrupted cell morphology, increased apoptosis and induced autophagy. Additionally, activation of JNK1/2 and p38 MAPK promoted apoptosis, while activation of ERK1/2 inhibited apoptosis. Upon inhibition of autophagy, apoptosis rate and the expression of ER proteins related to the apoptosis were increased. Following inhibition of the ERK1/2 signaling pathway, the number of LC3 aggregates, the rate of LC3II/LC3I and the expression of Beclin-1were decreased, but the expression level of ER proteins related to apoptosis were increased. Our results indicated that Cd exposure damages cells also induces apoptosis and autophagy, meanwhile demonstrate that the ERK1/2 signaling pathway plays an important role in this process. Besides, these data suggest that autophagy can inhibit Cd-induced apoptosis and the ERK1/2 signaling pathway can suppress ER stress-mediated apoptosis by activating autophagy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tiv.2018.06.001DOI Listing
October 2018

Inhibition of p70 S6 kinase activity by A77 1726 induces autophagy and enhances the degradation of superoxide dismutase 1 (SOD1) protein aggregates.

Cell Death Dis 2018 03 14;9(3):407. Epub 2018 Mar 14.

Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu Province, China.

Autophagy plays a central role in degrading misfolded proteins such as mutated superoxide dismutase 1 (SOD1), which forms aggregates in motor neurons and is involved in the pathogenesis of amyotrophic lateral sclerosis (ALS). Autophagy is activated when UNC-51-like kinase 1 (ULK1) is phosphorylated at S555 and activated by AMP-activated protein kinase (AMPK). Autophagy is suppressed when ULK1 is phosphorylated at S757 by the mechanistic target of rapamycin (mTOR). Whether p70 S6 kinase 1 (S6K1), a serine/threonine kinase downstream of mTOR, can also regulate autophagy remains uncertain. Here we report that inhibition of S6K1 by A77 1726, the active metabolite of an anti-inflammatory drug leflunomide, induced mTOR feedback activation and ULK1 phosphorylation in NSC34 cells, a hybrid mouse motoneuron cell line. Unexpectedly, A77 1726 did not suppress but rather induced autophagy by increasing AMPK and ULK1 phosphorylation. Similar observations were made with PF-4708671, a specific S6K1 inhibitor, or with S6K1 siRNA. Further studies showed that A77 1726 induced AMPK phosphorylation by activating the TGF-β-activated kinase 1 (TAK1). Functional studies revealed that A77 1726 induced co-localization of mutant SOD1 protein aggregates with autophagosomes and accelerated SOD1 protein degradation, which was blocked by inhibition of autophagy through autophagy-related protein 7 (ATG7) siRNA. Our study suggests that S6K1 inhibition induces autophagy through TAK1-mediated AMPK activation in NSC34 cells, and that blocking S6K1 activity by a small molecule inhibitor such as leflunomide may offer a new strategy for ALS treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41419-018-0441-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5851998PMC
March 2018

Zearalenone altered the cytoskeletal structure via ER stress- autophagy- oxidative stress pathway in mouse TM4 Sertoli cells.

Sci Rep 2018 02 20;8(1):3320. Epub 2018 Feb 20.

College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, China.

The aim of this study was to investigate the molecular mechanisms of the destruction of cytoskeletal structure by Zearalenone (ZEA) in mouse-derived TM4 cells. In order to investigate the role of autophagy, oxidative stress and endoplasmic reticulum(ER) stress in the process of destruction of cytoskeletal structure, the effects of ZEA on the cell viability, cytoskeletal structure, autophagy, oxidative stress, ER stress, MAPK and PI3K- AKT- mTOR signaling pathways were studied. The data demonstrated that ZEA damaged the cytoskeletal structure through the induction of autophagy that leads to the alteration of cytoskeletal structure via elevated oxidative stress. Our results further showed that the autophagy was stimulated by ZEA through PI3K-AKT-mTOR and MAPK signaling pathways in TM4 cells. In addition, ZEA also induced the ER stress which was involved in the induction of the autophagy through inhibiting the ERK signal pathway to suppress the phosphorylation of mTOR. ER stress was involved in the damage of cytoskeletal structure through induction of autophagy by producing ROS. Taken together, this study revealed that ZEA altered the cytoskeletal structure via oxidative stress - autophagy- ER stress pathway in mouse TM4 Sertoli cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-21567-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5820275PMC
February 2018

Beclin-1-mediated Autophagy Protects Against Cadmium-activated Apoptosis via the Fas/FasL Pathway in Primary Rat Proximal Tubular Cell Culture.

Sci Rep 2017 04 20;7(1):977. Epub 2017 Apr 20.

College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road, Yangzhou, 225009, People's Republic of China.

The Fas/FasL signaling pathway is one of the primary apoptosis pathways, but the involvement and regulatory mechanism of this pathway by autophagy remain unclear. Here we demonstrated that cadmium (Cd) activated the Fas/FasL apoptosis pathway in rat proximal tubular (rPT) cells; this was accompanied by simultaneous activation of autophagy resulted in reduced apoptosis. In this model, we induced autophagy through RAPA and further demonstrated that autophagy protects against activation of Fas/FasL signaling and apoptosis. The antiapoptotic effect of autophagy was blocked by 3-MA, an autophagy inhibitor. The interactions between Beclin-1 and Fas, FasL, FADD, caspase-8 and BID/tBID were relatively weak, with the exception of cleaved caspase-8, indicated that minimal interactions between these proteins and Beclin-1 are involved in maintaining the balance of autophagy and apoptosis. Beclin-1 precipitated with cleaved caspase-8 in a dose-dependent mannter, and the expression was increased by siRNA against Beclin-1. These data suggested that Beclin-1-mediated autophagy impairs the expression and function of cleaved caspase-8 to protect against Cd-induced activation of apopotosis through Fas/FasL signaling pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-00997-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5430518PMC
April 2017

Inhibition of p70 S6 kinase (S6K1) activity by A77 1726, the active metabolite of leflunomide, induces autophagy through TAK1-mediated AMPK and JNK activation.

Oncotarget 2017 May;8(18):30438-30454

Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030, USA.

mTOR activation suppresses autophagy by phosphorylating ULK1 at S757 and suppressing its enzymatic activity. Here we report that feedback activation of mTOR in the PI-3 kinase pathway by two p70 S6 kinase (S6K1) inhibitors (PF-4708671 and A77 1726, the active metabolite of an immunosuppressive drug leflunomide) or by S6K1 knockdown did not suppress but rather induced autophagy. Suppression of S6K1 activity led to the phosphorylation and activation of AMPK, which then phosphorylated ULK1 at S555. While mTOR feedback activation led to increased phosphorylation of ULK1 at S757, this modification did not the disrupt ULK1-AMPK interaction nor dampen ULK1 S555 phosphorylation and the induction of autophagy. In addition, inhibition of S6K1 activity led to JNK activation, which also contributed to autophagy. 5Z-7-oxozeaenol, a specific inhibitor of TAK1, or TAK1 siRNA blocked A77 1726-induced activation of AMPK and JNK, and LC3 lipidation. Taken together, our study establishes S6K1 as a key player in the PI-3 kinase pathway to suppress autophagy through inhibiting AMPK and JNK in a TAK1-dependent manner.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/oncotarget.16737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5444754PMC
May 2017

Caspase-Dependent and Caspase-Independent Pathways Are Involved in Cadmium-Induced Apoptosis in Primary Rat Proximal Tubular Cell Culture.

PLoS One 2016 18;11(11):e0166823. Epub 2016 Nov 18.

College of Veterinary Medicine, Yangzhou University, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, and Jiangsu Key Laboratory of Zoonosis, Yangzhou, Jiangsu, PR China.

We designed this study to investigate whether cadmium induces caspase-independent apoptosis and to investigate the relationship between the caspase-dependent and caspase-independent apoptotic pathways. Cadmium (1.25-2.5 μM) induced oxidative stress in rat proximal tubular (rPT) cells, as seen in the reactive oxygen species levels; N-acetylcysteine prevented this. Cyclosporin A (CsA) prevented mitochondrial permeability transition pore opening and apoptosis; there was mitochondrial ultrastructural disruption, mitochondrial cytochrome c (cyt c) translocation to the cytoplasm, and subsequent caspase-9 and caspase-3 activation. Z-VAD-FMK prevented caspase-3 activation and apoptosis and decreased BNIP-3 (Bcl-2/adenovirus E1B 19-kDa interacting protein 3) expression levels and apoptosis-inducing factor/endonuclease G (AIF/Endo G) translocation. Simultaneously, cadmium induced prominent BNIP-3 expression in the mitochondria and cytoplasmic AIF/Endo G translocation to the nucleus. BNIP-3 silencing significantly prevented AIF and Endo G translocation and decreased the apoptosis rate, cyt c release, and caspase-9 and caspase-3 activation. These results suggest that BNIP-3 is involved in the caspase-independent apoptotic pathway and is located upstream of AIF/Endo G; both the caspase-dependent and caspase-independent pathways are involved in cadmium-induced rPT cell apoptosis and act synergistically.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0166823PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5115828PMC
June 2017

Treatment of cadmium-induced renal oxidative damage in rats by administration of alpha-lipoic acid.

Environ Sci Pollut Res Int 2017 Jan 30;24(2):1832-1844. Epub 2016 Oct 30.

College of Veterinary Medicine, Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China.

Cadmium (Cd) is a toxic heavy metal that is widespread and nephrotoxic, but the mechanism of its toxicity is not well understood. Alpha-lipoic acid (α-LA) has a protective effect on Cd-induced oxidative stress, but the underlying mechanism is also not clear. This study aimed to confirm that Cd causes renal damage and to explore the potential underlying mechanism of α-LA to the kidney. Rats were randomly divided into four groups: control group, Cd group (50 mg/L CdAc), Cd+α-LA group (50 mg/L CdAc + 50 mg/kg body wt/day α-LA), and α-LA group (50 mg/kg body wt/day). The rats were exposed to Cd via drinking water and α-LA in the form of gavage at the same time every day. After 12 weeks, the activity of antioxidant enzymes and the level of Cd in the kidney were analyzed. Renal damage was evaluated based on histopathological and ultrastructure examinations. The apoptosis index was determined based on the results of western blotting and qRT-PCR. Our results indicate that accumulation of Cd causes serious kidney damage and α-LA has a protective effect against Cd-induced oxidative stress and apoptosis. Further, the findings indicate that the antioxidant, Cd chelation, and antiapoptotic activities of α-LA are the key factors that alleviate nephrotoxicity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-016-7953-xDOI Listing
January 2017
-->