JNK1 regulates RANKL‐induced osteoclastogenesis
            <i>via</i>
            activation of a novel Bcl‐2‐Beclin1‐autophagy pathway

Ke, Dianshan; Ji, Lianmei; Wang, Yu; Fu, Xiaomin; Chen, Jinyan; Wang, Fan; Zhao, Dongbao; Xue, Ying; Lan, Xu-hua; Hou, Jianming

doi:10.1096/fj.201802597rr

Cited by 42 publications

(45 citation statements)

References 58 publications

(92 reference statements)

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“…In addition, Annexin V–FITC/PI staining results showed that in the presence or absence of RANKL, the addition of 17β‐estradiol (5 nmol/L) promoted the apoptosis of OCPs (Figure ), which was similar to the previous results 19,20 . Furthermore, OCP apoptosis increased with RANKL treatment (Figure ), which was also consistent with previous research results showing that RANKL promoted OCP apoptosis at the beginning of the precursor stage 52,53 …”

Section: Resultssupporting

confidence: 91%

Oestrogen‐activated autophagy has a negative effect on the anti‐osteoclastogenic function of oestrogen

Cheng

Zhu

et al. 2020

Cell Proliferation

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Objectives Oestrogen is known to inhibit osteoclastogenesis, and numerous studies have identified it as an autophagic activator. To date, the role of oestrogen in the autophagy of osteoclast precursors (OCPs) during osteoclastogenesis remains unclear. This study aimed to determine the effect of autophagy regulated by the biologically active form of oestrogen (17β‐estradiol) on osteoclastogenesis. Materials and methods After treatment with 17β‐estradiol in OCPs (from bone marrow‐derived macrophages, BMMs) and ovariectomy (OVX) mice, we measured the effect of 17β‐estradiol on the autophagy of OCPs in vitro and in vivo. In addition, we studied the role of autophagy in the OCP proliferation, osteoclast differentiation and bone loss regulated by 17β‐estradiol using autophagic inhibitor or knock‐down of autophagic genes. Results The results showed that direct administration of 17β‐estradiol enhanced the autophagic response of OCPs. Interestingly, 17β‐estradiol inhibited the stimulatory effect of receptor activator of nuclear factor‐κB ligand (RANKL) on the autophagy and osteoclastogenesis of OCPs. Moreover, 17β‐estradiol inhibited the downstream signalling of RANKL. Autophagic suppression by pharmacological inhibitors or gene silencing enhanced the inhibitory effect of 17β‐estradiol on osteoclastogenesis. In vivo assays showed that the autophagic inhibitor 3‐MA not only inhibited the autophagic activity of the OCPs in the trabecular bone of OVX mice but also enhanced the ability of 17β‐estradiol to ameliorate bone loss. Conclusions In conclusion, our study showed that oestrogen directly enhanced the autophagy of OCPs, which inhibited its anti‐osteoclastogenic effect. Drugs based on autophagic inhibition may enhance the efficacy of oestrogen on osteoporosis.

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Section: Resultssupporting

confidence: 91%

Oestrogen‐activated autophagy has a negative effect on the anti‐osteoclastogenic function of oestrogen

Cheng

Zhu

et al. 2020

Cell Proliferation

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“…In addition to the integrity of autophagy to the bioactivity of the host cells, novel data highlighted the interaction and interplay of the autophagy signaling pathway with another signaling cascade reciprocally [11]. Scientific literature demonstrated that autophagy functions in the developmental and maturation of B lymphocytes, adipocytes, osteoblasts, keratinocytes and erythrocytes [12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Autophagy modulation altered differentiation capacity of CD146+ cells toward endothelial cells, pericytes, and cardiomyocytes

Hassanpour

Rezaie

Darabi

et al. 2020

Preprint

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Background: To date, many attempts are employed to increase the regenerative potential of stem cells. In this study, we evaluated the hypothesis whether an autophagy modulation could induce/reduce CD146+ cells differentiation into mature pericyte, endothelial and cardiomyocyte lineage. Methods In this study, CD146+ cells were enriched from human bone marrow aspirates and trans-differentiated into mature EC, PC and CM after exposure to autophagy stimulator (50 µM Met)/inhibitor (15 µM HCQ). The protein levels of autophagy proteins were monitored by western blotting. NO content was measured using the Griess assay. Using real-time PCR assay and western blotting, we monitored the lineage protein and gene levels. The fatty acid change was determined by gas chromatography. Pro-inflammatory cytokine and angiocrine factors were measured by ELISA. The exosome secretion capacity was assessed by AChE activity and real-time PCR assay. Result Data revealed the modulation of autophagy factors, Beclin-1, P62 and LC3 II/I ratio in differentiating CD146+ cells after exposure to Met and HCQ (p<0.05). The inhibition of autophagy increased released NO content and decreased intracellular NO content compared to the Met-treated cells (p<0.05). Real-time PCR analysis showed that the treatment of CD146+ cells with autophagy modulators altered the expression of VE-cadherin, cTnI and α-SMA. Our data demonstrated that the stimulation of autophagy signaling in CD146+ cells with Met increased the expression of VE-cadherin, α-SMA, and cTnI compared to HCQ-treated cells (p<0.05) while western blotting revealed the protein synthesis of all lineage-specific proteins in under the stimulation and inhibition of autophagy. Fatty acid profile analysis revealed the increase of unsaturated fatty acids after exposure to HCQ (p<0.05). None statistically significant differences were found in the levels of Tie-1, Tie-2, VEGFR-1 and VEGFR-2 after autophagy modulation. The treatment of cells with HCQ increased the levels of TNF-α and IL-6 compared to the Met-treated cells. Data revealed the increase of exosome biogenesis and secretion to the supernatant in cells treated with HCQ compared to the Met groups (p<0.05).ConclusionsIn summary, autophagy modulation could be altered differentiation potency of CD146+ cells and could be novel and applicable cardiac cell therapy in the cardiac regeneration field.

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“…Dissociation of the Beclin 1-Bcl-2 complex stimulates autophagy in response to conditions of nutrient deprivation and other cellular stresses [24]. Previous reports have demonstrated that Bcl-2 is phosphorylated at multiple sites, including threonine 69, serine 70 and serine 87, by JNK, causing the dissociation of Beclin 1 and the induction of autophagy [25]. Because ROP17 contains conserved ATP-binding residues and catalytic triads that are essential for S/T kinases, similar to JNK [26], we sought to determine whether ROP17 can phosphorylate Bcl-2 and then liberate Beclin 1 to trigger autophagy.…”

Section: Tgrop17 Phosphorylates Bcl-2 To Induce the Dissociation Of Tmentioning

confidence: 99%

Toxoplasma Gondii ROP17 Promotes Autophagy via the Bcl-2–Beclin 1 Pathway

Guo

Jia

Wang

et al. 2020

Preprint

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Abstract Background Toxoplasmosis caused by Toxoplasma gondii (T. gondii) has been and continues to be a major threat to public health worldwide. Proteins with serine/threonine (S/T) kinase activity, such as rhoptry organelle protein (ROP)16 and ROP18, are secreted by T. gondii rhoptries organelles that play important roles in modulating the survival and proliferation of Toxoplasma. ROP17 is another important effector kinase protein. Nevertheless, little is known about its function in regulating the interplay between T. gondii and host cells during infection. In this study, we investigated the function and the underlying mechanisms of ROP17 in vitro and in vivo. Methods The autophagy of cells in the small intestines of mice infected with T. gondii tachyzoite (RH strain) was detected by assessing the LC3B, Beclin 1 and p62 levels using immunohistochemical staining. ROP17 overexpression augmented starvation-induced autophagy in HEK 293T cells as measured by MDC staining, transmission electron microscopy (TEM), fluorescence microscopy and Western blot analysis. The interaction of ROP17 and Bcl-2 was confirmed using co-immunoprecipitation (co-IP) analysis. Moreover, the levels of phosphorylation of Bcl-2 and total Bcl-2 in the small intestines of mice infected with T. gondii tachyzoite were detected using immunohistochemical staining. In the end, Pearson coefficient was used to analyse correlations between the expression of ROP17 with the expression of autophagy markers LC3B, beclin 1 and p62, and with phosphorylation of Bcl-2 and Bcl-2. Results Infection with T. gondii resulted in autophagy of mouse small intestine cells accompanied by increased levels of LC3B and Beclin 1 and decreased levels of p62, which were measured by immunohistochemistry. Meantime, the elevated levels of Phosphorylated Bcl-2 and declined Bcl-2 in T. gondii-infected mouse small intestine tissue and in ROP17 overexpressing HEK 293T cells were detected by immunohistochemistry and Western blotting. ROP17 overexpression promoted serum starvation-induced cellular autophagy in the HEK293T cells, reflecting the augmentation of autophagosomes and GFP-LC3B puncta accompanied by increased levels of LC3B and Beclin 1 and decreased levels of p62. Moreover, we found that ROP17 interacted with Bcl-2 and phosphorylated and degraded it to liberate Beclin 1, thus promoting autophagy. Pearson coefficient analysis showed that there exsited strong positive correlations between the expression of ROP17 with the expression of LC3B, Beclin 1 and phosphorylation of Bcl-2, while strong negative correlations between the expression of ROP17 and the expression of p62 and Bcl-2. Conclusions Our findings indicate that ROP17 plays a pivotal role in maintaining Toxoplasma survival and proliferation in host cells by promoting cellular autophagy, which depends on the Beclin 1-Bcl-2 pathway.

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JNK1 regulates RANKL‐induced osteoclastogenesis via activation of a novel Bcl‐2‐Beclin1‐autophagy pathway

Cited by 42 publications

References 58 publications

Oestrogen‐activated autophagy has a negative effect on the anti‐osteoclastogenic function of oestrogen

Oestrogen‐activated autophagy has a negative effect on the anti‐osteoclastogenic function of oestrogen

Autophagy modulation altered differentiation capacity of CD146+ cells toward endothelial cells, pericytes, and cardiomyocytes

Toxoplasma Gondii ROP17 Promotes Autophagy via the Bcl-2–Beclin 1 Pathway

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