ULK1 Suppresses Osteoclast Differentiation and Bone Resorption via Inhibiting Syk-JNK through DOK3

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/2896674 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Yufeng Zhang ◽

Sheng Zhang ◽

Yi Wang ◽

Zhiqiang Yang ◽

Zhe Chen ◽

...

Keyword(s):

Bone Resorption ◽

Osteoclast Differentiation ◽

Bone Homeostasis ◽

Serine Threonine Kinase ◽

Threonine Kinase ◽

Osteolytic Metastasis ◽

Docking Protein

Bone resorption diseases, including osteoporosis, are usually caused by excessive osteoclastogenesis. Unc-51-like autophagy activating kinase 1 (ULK1), a mammalian serine/threonine kinase, may participate in the regulation of bone homeostasis and osteolytic metastasis. In this study, ULK1 expression during osteoclastogenesis was detected with RT-PCR. We knocked down or overexpressed ULK1 through siRNA or lentiviral transduction in bone marrow macrophage (BMM). TRAP and phalloidin staining were performed to detect the osteoclastogenesis activity. Ovariectomized (OVX) mouse model of osteoporosis and a mouse of model osteoclast-induced bone resorption were applied to explore the role of ULK1 in bone resorption in vivo. The results showed that ULK1 expression was downregulated during osteoclast differentiation and was clinically associated with osteoporosis. ULK1 inhibited osteoclast differentiation in vitro. Knockdown of ULK1 expression activated phosphorylation of c-Jun N-terminal kinase (JNK) and spleen tyrosine kinase (Syk). Docking protein 3 (DOK3) was coexpressed with ULK1 during osteoclastogenesis. Downregulation of DOK3 offsets the effect of ULK1 on osteoclastogenesis and induced phosphorylation of JNK and Syk. Activation of ULK1 impeded bone loss in OVX mice with osteoporosis. Additionally, upregulation of ULK1 inhibited osteoclast-induced bone resorption in vivo. Therefore, our study reveals a novel ULK1/DOK3/Syk axis that regulates osteoclast differentiation and bone resorption, and targeting ULK1 is a potential therapeutic strategy for osteoporosis.

Download Full-text

Autoamplification of NFATc1 expression determines its essential role in bone homeostasis

Journal of Experimental Medicine ◽

10.1084/jem.20051150 ◽

2005 ◽

Vol 202 (9) ◽

pp. 1261-1269 ◽

Cited By ~ 558

Author(s):

Masataka Asagiri ◽

Kojiro Sato ◽

Takako Usami ◽

Sae Ochi ◽

Hiroshi Nishina ◽

...

Keyword(s):

Essential Role ◽

Osteoclast Differentiation ◽

Ectopic Expression ◽

Epigenetic Mechanism ◽

Bone Homeostasis ◽

Hematopoietic Stem ◽

Vitro Effect

NFATc1 and NFATc2 are functionally redundant in the immune system, but it was suggested that NFATc1 is required exclusively for differentiation of osteoclasts in the skeletal system. Here we provide genetic evidence that NFATc1 is essential for osteoclast differentiation in vivo by adoptive transfer of NFATc1−/− hematopoietic stem cells to osteoclast-deficient Fos−/− mice, and by Fos−/− blastocyst complementation, thus avoiding the embryonic lethality of NFATc1−/− mice. However, in vitro osteoclastogenesis in NFATc1-deficient cells was rescued by ectopic expression of NFATc2. The discrepancy between the in vivo essential role of NFATc1 and the in vitro effect of NFATc2 was attributed to selective autoregulation of the NFATc1 gene by NFAT through its promoter region. This suggested that an epigenetic mechanism contributes to the essential function of NFATc1 in cell lineage commitment. Thus, this study establishes that NFATc1 represents a potential therapeutic target for bone disease and reveals a mechanism that underlies the essential role of NFATc1 in bone homeostasis.

Download Full-text

ELMO1 Regulates RANKL-Stimulated Differentiation and Bone Resorption of Osteoclasts

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.702916 ◽

2021 ◽

Vol 9 ◽

Author(s):

Xinyue Liang ◽

Yafei Hou ◽

Lijuan Han ◽

Shuxiang Yu ◽

Yunyun Zhang ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Bone Resorption ◽

Bone Erosion ◽

Osteoclast Differentiation ◽

Small Gtpases ◽

Bone Diseases ◽

Bone Homeostasis ◽

Nucleotide Exchange

Bone homeostasis is a metabolic balance between the new bone formation by osteoblasts and old bone resorption by osteoclasts. Excessive osteoclastic bone resorption results in low bone mass, which is the major cause of bone diseases such as rheumatoid arthritis. Small GTPases Rac1 is a key regulator of osteoclast differentiation, but its exact mechanism is not fully understood. ELMO and DOCK proteins form complexes that function as guanine nucleotide exchange factors for Rac activation. Here, we report that ELMO1 plays an important role in differentiation and bone resorption of osteoclasts. Osteoclast precursors derived from bone marrow monocytes (BMMs) of Elmo1–/– mice display defective adhesion and migration during differentiation. The cells also have a reduced activation of Rac1, p38, JNK, and AKT in response to RANKL stimulation. Importantly, we show that bone erosion is alleviated in Elmo1–/– mice in a rheumatoid arthritis mouse model. Taken together, our results suggest that ELMO1, as a regulator of Rac1, regulates osteoclast differentiation and bone resorption both in vitro and in vivo.

Download Full-text

An Inducible and Secreted Eukaryote-Like Serine/Threonine Kinase of Salmonella enterica Serovar Typhi Promotes Intracellular Survival and Pathogenesis

Infection and Immunity ◽

10.1128/iai.02521-14 ◽

2014 ◽

Vol 83 (2) ◽

pp. 522-533 ◽

Cited By ~ 4

Author(s):

Nagaraja Theeya ◽

Atri Ta ◽

Sayan Das ◽

Rahul S. Mandal ◽

Oishee Chakrabarti ◽

...

Keyword(s):

Salmonella Enterica ◽

Functional Characterization ◽

Systemic Infection ◽

Serine Threonine Kinase ◽

Content Type ◽

Threonine Kinase ◽

Universal Substrate

Eukaryote-like serine/threonine kinases (eSTKs) constitute an important family of bacterial virulence factors. Genome analysis had predicted putative eSTKs inSalmonella entericaserovar Typhi, although their functional characterization and the elucidation of their role in pathogenesis are still awaited. We show here that the primary sequence and secondary structure of thet4519locus ofSalmonellaTyphi Ty2 have all the signatures of eukaryotic superfamily kinases.t4519encodes a ∼39-kDa protein (T4519), which shows serine/threonine kinase activitiesin vitro. Recombinant T4519 (rT4519) is autophosphorylated and phosphorylates the universal substrate myelin basic protein. Infection of macrophages results in decreased viability of the mutant (Ty2Δt4519) strain, which is reversed by gene complementation. Moreover, reactive oxygen species produced by the macrophages signal to the bacteria to induce T4519, which is translocated to the host cell cytoplasm. That T4519 may target a host substrate(s) is further supported by the activation of host cellular signaling pathways and the induction of cytokines/chemokines. Finally, the role of T4519 in the pathogenesis ofSalmonellaTyphi is underscored by the significantly decreased mortality of mice infected with the Ty2Δt4519strain and the fact that the competitive index of this strain for causing systemic infection is 0.25% that of the wild-type strain. This study characterizes the first eSTK ofSalmonellaTyphi and demonstrates its role in promoting phagosomal survival of the bacteria within macrophages, which is a key determinant of pathogenesis. This, to the best of our knowledge, is the first study to describe the essential role of eSTKs in thein vivopathogenesis ofSalmonellaspp.

Download Full-text

A phyB-PIF1-SPA1 kinase regulatory complex promotes photomorphogenesis in Arabidopsis

Nature Communications ◽

10.1038/s41467-019-12110-y ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 21

Author(s):

Inyup Paik ◽

Fulu Chen ◽

Vinh Ngoc Pham ◽

Ling Zhu ◽

Jeong-Il Kim ◽

...

Keyword(s):

Red Light ◽

Kinase Domain ◽

Serine Threonine Kinase ◽

Threonine Kinase ◽

C Terminus ◽

Subsequent Degradation ◽

Regulatory Complex

Abstract CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) is a highly conserved E3 ubiquitin ligase from plants to animals and acts as a central repressor of photomorphogenesis in plants. SUPPRESSOR OF PHYA-105 1 family members (SPA1-SPA4) directly interact with COP1 and enhance COP1 activity. Despite the presence of a kinase domain at the N-terminus, no COP1-independent role of SPA proteins has been reported. Here we show that SPA1 acts as a serine/threonine kinase and directly phosphorylates PIF1 in vitro and in vivo. SPAs are necessary for the light-induced phosphorylation, ubiquitination and subsequent degradation of PIF1. Moreover, the red/far-red light photoreceptor phyB interacts with SPA1 through its C-terminus and enhances the recruitment of PIF1 for phosphorylation. These data provide a mechanistic view on how the COP1-SPA complexes serve as an example of a cognate kinase-E3 ligase complex that selectively triggers rapid phosphorylation and removal of its substrates, and how phyB modulates this process to promote photomorphogenesis.

Download Full-text

The Cytoplasmic Dynein Associated Protein NDE1 Regulates Osteoclastogenesis by Modulating M-CSF and RANKL Signaling Pathways

Cells ◽

10.3390/cells11010013 ◽

2021 ◽

Vol 11 (1) ◽

pp. 13

Author(s):

Bhaba K. Das ◽

Jyoti Gogoi ◽

Aarthi Kannan ◽

Ling Gao ◽

Weirong Xing ◽

...

Keyword(s):

Bone Resorption ◽

Signaling Pathways ◽

Osteoclast Differentiation ◽

Cytoplasmic Dynein ◽

Conditional Knockout ◽

Bone Homeostasis ◽

Cytoskeleton Organization ◽

Osteoclast Precursors

Cytoskeleton organization and lysosome secretion play an essential role in osteoclastogenesis and bone resorption. The cytoplasmic dynein is a molecular motor complex that regulates microtubule dynamics and transportation of cargos/organelles, including lysosomes along the microtubules. LIS1, NDE1, and NDEL1 belong to an evolutionary conserved pathway that regulates dynein functions. Disruption of the cytoplasmic dynein complex and deletion of LIS1 in osteoclast precursors arrest osteoclastogenesis. Nonetheless, the role of NDE1 and NDEL1 in osteoclast biology remains elusive. In this study, we found that knocking-down Nde1 expression by lentiviral transduction of specific shRNAs markedly inhibited osteoclastogenesis in vitro by attenuating the proliferation, survival, and differentiation of osteoclast precursor cells via suppression of signaling pathways downstream of M-CSF and RANKL as well as osteoclast differentiation transcription factor NFATc1. To dissect how NDEL1 regulates osteoclasts and bone homeostasis, we generated Ndel1 conditional knockout mice in myeloid osteoclast precursors (Ndel1ΔlysM) by crossing Ndel1-floxed mice with LysM-Cre mice on C57BL/6J background. The Ndel1ΔlysM mice developed normally. The µCT analysis of distal femurs and in vitro osteoclast differentiation and functional assays in cultures unveiled the similar bone mass in both trabecular and cortical bone compartments as well as intact osteoclastogenesis, cytoskeleton organization, and bone resorption in Ndel1ΔlysM mice and cultures. Therefore, our results reveal a novel role of NDE1 in regulation of osteoclastogenesis and demonstrate that NDEL1 is dispensable for osteoclast differentiation and function.

Download Full-text

Alternative regulatory mechanism for the maintenance of bone homeostasis via STAT5-mediated regulation of the differentiation of BMSCs into adipocytes

Experimental & Molecular Medicine ◽

10.1038/s12276-021-00616-9 ◽

2021 ◽

Author(s):

Semun Seong ◽

Jung Ha Kim ◽

Kabsun Kim ◽

Inyoung Kim ◽

Jeong-Tae Koh ◽

...

Keyword(s):

Bone Marrow ◽

Bone Loss ◽

Target Genes ◽

Osteoclast Differentiation ◽

Conditional Knockout ◽

Negative Regulator ◽

Bone Homeostasis

AbstractSTAT5 is a transcription factor that is activated by various cytokines, hormones, and growth factors. Activated STAT5 is then translocated to the nucleus and regulates the transcription of target genes, affecting several biological processes. Several studies have investigated the role of STAT5 in adipogenesis, but unfortunately, its role in adipogenesis remains controversial. In the present study, we generated adipocyte-specific Stat5 conditional knockout (cKO) (Stat5fl/fl;Apn-cre) mice to investigate the role of STAT5 in the adipogenesis of bone marrow mesenchymal stem cells (BMSCs). BMSC adipogenesis was significantly inhibited upon overexpression of constitutively active STAT5A, while it was enhanced in the absence of Stat5 in vitro. In vivo adipose staining and histological analyses revealed increased adipose volume in the bone marrow of Stat5 cKO mice. ATF3 is the target of STAT5 during STAT5-mediated inhibition of adipogenesis, and its transcription is regulated by the binding of STAT5 to the Atf3 promoter. ATF3 overexpression was sufficient to suppress the enhanced adipogenesis of Stat5-deficient adipocytes, and Atf3 silencing abolished the STAT5-mediated inhibition of adipogenesis. Stat5 cKO mice exhibited reduced bone volume due to an increase in the osteoclast number, and coculture of bone marrow-derived macrophages with Stat5 cKO adipocytes resulted in enhanced osteoclastogenesis, suggesting that an increase in the adipocyte number may contribute to bone loss. In summary, this study shows that STAT5 is a negative regulator of BMSC adipogenesis and contributes to bone homeostasis via direct and indirect regulation of osteoclast differentiation; therefore, it may be a leading target for the treatment of both obesity and bone loss-related diseases.

Download Full-text

Biological Effects of β-Glucans on Osteoclastogenesis

Molecules ◽

10.3390/molecules26071982 ◽

2021 ◽

Vol 26 (7) ◽

pp. 1982

Author(s):

Wataru Ariyoshi ◽

Shiika Hara ◽

Ayaka Koga ◽

Yoshie Nagai-Yoshioka ◽

Ryota Yamasaki

Keyword(s):

Bone Resorption ◽

Bone Marrow Cells ◽

Biological Effects ◽

Osteoclast Differentiation ◽

Treatment Strategies ◽

Alcaligenes Faecalis ◽

Osteoclast Formation ◽

Osteoclast Precursors

Although the anti-tumor and anti-infective properties of β-glucans have been well-discussed, their role in bone metabolism has not been reviewed so far. This review discusses the biological effects of β-glucans on bone metabolisms, especially on bone-resorbing osteoclasts, which are differentiated from hematopoietic precursors. Multiple immunoreceptors that can recognize β-glucans were reported to be expressed in osteoclast precursors. Coordinated co-stimulatory signals mediated by these immunoreceptors are important for the regulation of osteoclastogenesis and bone remodeling. Curdlan from the bacterium Alcaligenes faecalis negatively regulates osteoclast differentiation in vitro by affecting both the osteoclast precursors and osteoclast-supporting cells. We also showed that laminarin, lichenan, and glucan from baker’s yeast, as well as β-1,3-glucan from Euglema gracilisas, inhibit the osteoclast formation in bone marrow cells. Consistent with these findings, systemic and local administration of β-glucan derived from Aureobasidium pullulans and Saccharomyces cerevisiae suppressed bone resorption in vivo. However, zymosan derived from S. cerevisiae stimulated the bone resorption activity and is widely used to induce arthritis in animal models. Additional research concerning the relationship between the molecular structure of β-glucan and its effect on osteoclastic bone resorption will be beneficial for the development of novel treatment strategies for bone-related diseases.

Download Full-text

Lumican Inhibits Osteoclastogenesis and Bone Resorption by Suppressing Akt Activity

International Journal of Molecular Sciences ◽

10.3390/ijms22094717 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4717

Author(s):

Jin-Young Lee ◽

Da-Ae Kim ◽

Eun-Young Kim ◽

Eun-Ju Chang ◽

So-Jeong Park ◽

...

Keyword(s):

Bone Resorption ◽

Bone Formation ◽

Map Kinases ◽

Osteoclast Differentiation ◽

Dependent Manner ◽

Dual Action ◽

Dose Dependent ◽

Resorptive Activity

Lumican, a ubiquitously expressed small leucine-rich proteoglycan, has been utilized in diverse biological functions. Recent experiments demonstrated that lumican stimulates preosteoblast viability and differentiation, leading to bone formation. To further understand the role of lumican in bone metabolism, we investigated its effects on osteoclast biology. Lumican inhibited both osteoclast differentiation and in vitro bone resorption in a dose-dependent manner. Consistent with this, lumican markedly decreased the expression of osteoclastogenesis markers. Moreover, the migration and fusion of preosteoclasts and the resorptive activity per osteoclast were significantly reduced in the presence of lumican, indicating that this protein affects most stages of osteoclastogenesis. Among RANKL-dependent pathways, lumican inhibited Akt but not MAP kinases such as JNK, p38, and ERK. Importantly, co-treatment with an Akt activator almost completely reversed the effect of lumican on osteoclast differentiation. Taken together, our findings revealed that lumican inhibits osteoclastogenesis by suppressing Akt activity. Thus, lumican plays an osteoprotective role by simultaneously increasing bone formation and decreasing bone resorption, suggesting that it represents a dual-action therapeutic target for osteoporosis.

Download Full-text

WNK4 Kinase: from structure to physiology

AJP Renal Physiology ◽

10.1152/ajprenal.00634.2020 ◽

2021 ◽

Author(s):

Adrian Rafael Murillo-de-Ozores ◽

Alejandro Rodriguez-Gama ◽

Hector Carbajal-Contreras ◽

Gerardo Gamba ◽

Maria Castaneda-Bueno

Keyword(s):

Oxidative Stress ◽

Mouse Models ◽

Serine Threonine Kinase ◽

Gene Encoding ◽

Threonine Kinase ◽

Physiological Conditions ◽

Different Levels ◽

Familial Hyperkalemic Hypertension

With No Lysine (K) kinase 4 (WNK4) belongs to a serine-threonine kinase family characterized by the atypical positioning of its catalytic lysine. Despite the fact that WNK4 has been found in many tissues, the majority of its study has revolved around its function in the kidney, specifically as a positive regulator of the thiazide-sensitive NaCl cotransporter (NCC) in the distal convoluted tubule (DCT) of the nephron. This is explained by the description of gain-of-function mutations in the gene encoding WNK4 that cause Familial Hyperkalemic Hypertension (FHHt). This disease is mainly driven by increased downstream activation of the Ste20-related Proline Alanine Rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1)-NCC pathway, which increases salt reabsorption in the DCT and indirectly impairs renal K+ secretion. Here, we review the large volume of information that has accumulated about different aspects of WNK4 function. We first review the knowledge on WNK4 structure and enumerate the functional domains and motifs that have been characterized. Then, we discuss WNK4 physiological functions based on the information obtained from in vitro studies and from a diverse set of genetically modified mouse models with altered WNK4 function. We then review in vitro and in vivo evidence on the different levels of regulation of WNK4. Finally, we go through the evidence that has suggested how different physiological conditions act through WNK4 to modulate NCC activity.

Download Full-text