Muscle-specific E3 ubiquitin ligases are involved in muscle atrophy of cancer cachexia: An in vitro and in vivo study

Muscle-specific E3 ubiquitin ligases have been identified in muscle atrophy-inducing conditions. The purpose of the current study was to explore the functional role of F-box and leucine-rich protein 22 (Fbxl22), and a newly identified splice variant (Fbxl22–193), in skeletal muscle homeostasis and neurogenic muscle atrophy. In mouse C2C12 muscle cells, promoter fragments of the Fbxl22 gene were cloned and fused with the secreted alkaline phosphatase reporter gene to assess the transcriptional regulation of Fbxl22. The tibialis anterior muscles of male C57/BL6 mice (12–16 wk old) were electroporated with expression plasmids containing the cDNA of two Fbxl22 splice variants and tissues collected after 7, 14, and 28 days. Gastrocnemius muscles of wild-type and muscle-specific RING finger 1 knockout (MuRF1 KO) mice were electroporated with an Fbxl22 RNAi or empty plasmid and denervated 3 days posttransfection, and tissues were collected 7 days postdenervation. The full-length gene and novel splice variant are transcriptionally induced early (after 3 days) during neurogenic muscle atrophy. In vivo overexpression of Fbxl22 isoforms in mouse skeletal muscle leads to evidence of myopathy/atrophy, suggesting that both are involved in the process of neurogenic muscle atrophy. Knockdown of Fbxl22 in the muscles of MuRF1 KO mice resulted in significant additive muscle sparing 7 days after denervation. Targeting two E3 ubiquitin ligases appears to have a strong additive effect on protecting muscle mass loss with denervation, and these findings have important implications in the development of therapeutic strategies to treat muscle atrophy.

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The E3 ubiquitin-protein ligase MDM2 is a novel interactor of the von Hippel–Lindau tumor suppressor

Scientific Reports ◽

10.1038/s41598-020-72683-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Antonella Falconieri ◽

Giovanni Minervini ◽

Raissa Bortolotto ◽

Damiano Piovesan ◽

Raffaele Lopreiato ◽

...

Keyword(s):

Tumor Suppressor ◽

Protein Interactions ◽

Specific Interaction ◽

Hypoxia Inducible Factor ◽

Ubiquitin Ligases ◽

E3 Ubiquitin Ligases ◽

Von Hippel Lindau ◽

Intrinsically Disordered

Abstract Mutations of the von Hippel–Lindau (pVHL) tumor suppressor are causative of a familiar predisposition to develop different types of cancer. pVHL is mainly known for its role in regulating hypoxia-inducible factor 1 α (HIF-1α) degradation, thus modulating the hypoxia response. There are different pVHL isoforms, including pVHL30 and pVHL19. However, little is known about isoform-specific functions and protein–protein interactions. Integrating in silico predictions with in vitro and in vivo assays, we describe a novel interaction between pVHL and mouse double minute 2 homolog (MDM2). We found that pVHL30, and not pVHL19, forms a complex with MDM2, and that the N-terminal acidic tail of pVHL30 is required for its association with MDM2. Further, we demonstrate that an intrinsically disordered region upstream of the tetramerization domain of MDM2 is responsible for its isoform-specific association with pVHL30. This region is highly conserved in higher mammals, including primates, similarly to what has been already shown for the N-terminal tail of pVHL30. Finally, we show that overexpression of pVHL30 and MDM2 together reduces cell metabolic activity and necrosis, suggesting a synergistic effect of these E3 ubiquitin ligases. Collectively, our data show an isoform-specific interaction of pVHL with MDM2, suggesting an interplay between these two E3 ubiquitin ligases.

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Identification and Characterization of Fbxl22, a novel skeletal muscle atrophy-promoting E3 ubiquitin ligase

10.1101/2020.04.24.059659 ◽

2020 ◽

Author(s):

David C. Hughes ◽

Leslie M Baehr ◽

Julia R. Driscoll ◽

Sarah A Lynch ◽

David S. Waddell ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Atrophy ◽

Splice Variant ◽

Splice Variants ◽

Ubiquitin Ligases ◽

Skeletal Muscle Atrophy ◽

E3 Ubiquitin Ligases ◽

Muscle Mass Loss ◽

Muscle Homeostasis

Muscle-specific E3 ubiquitin ligases have been identified in muscle atrophy-inducing conditions. The purpose of the current study was to explore the functional role of Fbxl22, and a newly identified splice variant (Fbxl22-193), in skeletal muscle homeostasis and neurogenic muscle atrophy. In mouse C2C12 muscle cells, promoter fragments of the Fbxl22 gene were cloned and fused with the secreted alkaline phosphatase reporter gene to assess the transcriptional regulation of Fbxl22. The tibialis anterior muscles of male C57/BL6 mice (12-16 weeks old) were electroporated with expression plasmids containing the cDNA of two Fbxl22 splice variants and tissues collected after 7, 14 and 28 days. Gastrocnemius muscles of wild type and MuRF1 knockout mice were electroporated with an Fbxl22 RNAi or empty plasmid, denervated three days post-transfection, and tissues collected 7 days post-denervation. The full-length gene and novel splice variant are transcriptionally induced early (after 3 days) during neurogenic muscle atrophy. In vivo overexpression of Fbxl22 isoforms in mouse skeletal muscle lead to evidence of myopathy/atrophy suggesting that both are involved in the process of neurogenic muscle atrophy. Knockdown of Fbxl22 in MuRF1 KO muscles resulted in significant additive muscle sparing at 7 days of denervation. Targeting two E3 ubiquitin ligases appears to have a strong additive effect on protecting muscle mass loss with denervation and these findings have important implications in the development of therapeutic strategies to treat muscle atrophy.

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Linalool Prevents Cisplatin Induced Muscle Atrophy by Regulating IGF-1/Akt/FoxO Pathway

Frontiers in Pharmacology ◽

10.3389/fphar.2020.598166 ◽

2020 ◽

Vol 11 ◽

Author(s):

Hong Zhang ◽

Mengyi Chi ◽

Linlin Chen ◽

Xipeng Sun ◽

Lili Wan ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Atrophy ◽

Cancer Cachexia ◽

Ring Finger ◽

Skeletal Muscle Atrophy ◽

Lewis Lung Cancer ◽

Muscle Weight ◽

C2c12 Myotube

Skeletal muscle atrophy is an important feature of cancer cachexia, which can be induced by chemotherapy, and affects the survival and quality of life of cancer patients seriously. No specific drugs for cancer cachexia have been applied in clinical practice. This study explored the therapeutic effect of linalool (LIN) on cisplatin (DDP) induced skeletal muscle atrophy. In vivo, LIN can improve skeletal muscle weight loss, anorexia, muscle strength decline and other cachexia symptoms caused by cisplatin treatment in a Lewis lung cancer tumor bearing mouse model, and cause no adverse effects on the anti-tumour effect. LIN treatment decreased the expression of muscle RING-finger protein-1 (MuRF1) and Atrogin1(MAFbx) in muscle, and the activation of insulin-like growth factor-1 (IGF-1)/protein kinase B (Akt)/forkhead box O (FoxO) pathway was observed. In vitro, LIN alleviated DDP induced C2C12 myotube atrophy, and IGF-1 receptor inhibitor Picropodophyllin (PIC), which had no adverse effect on C2C12 myotube cells, could reverse the protective effect of LIN. These results indicate that LIN down-regulates the expression of Atrogin1 and MuRF1 through the IGF-1/Akt/FoxO pathway, alleviating DDP-induced muscle atrophy and improving cachexia symptoms. LIN has the potential to be developed as a drug against cancer cachexia.

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Faculty Opinions recommendation of A pivotal role for heat shock protein 90 in Ewing sarcoma resistance to anti-insulin-like growth factor 1 receptor treatment: in vitro and in vivo study.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1120094.576229 ◽

2008 ◽

Author(s):

Richard Riedel

Keyword(s):

Growth Factor ◽

Heat Shock ◽

Heat Shock Protein ◽

Ewing Sarcoma ◽

Heat Shock Protein 90 ◽

Pivotal Role ◽

In Vivo Study ◽

Insulin Like Growth Factor

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Biological effect of Egyptian Propolis on BHK cell line and on dental pulp tissue (An In vitro And In vivo study)

Egyptian Dental Journal ◽

10.21608/edj.2018.76780 ◽

2018 ◽

Vol 64 (3) ◽

pp. 2161-2170

Author(s):

Marwa Moussa ◽

Marwa Temirek

Keyword(s):

Cell Line ◽

Dental Pulp ◽

Biological Effect ◽

In Vivo Study ◽

Pulp Tissue ◽

Dental Pulp Tissue

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Formulation and Evaluation of Atorvastatin Calcium-Poly-ε-Caprolactone Nanoparticles Loaded Ocular Inserts for Sustained Release and Antiinflammatory Efficacy

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200519133350 ◽

2020 ◽

Vol 21 (15) ◽

pp. 1688-1698

Author(s):

Germeen N.S. Girgis

Keyword(s):

Sustained Release ◽

In Vitro Release ◽

Pluronic F127 ◽

In Vivo Study ◽

Average Weight ◽

Drug Release Profile ◽

Atorvastatin Calcium ◽

Anti Inflammatory

Purpose: The work was performed to investigate the feasibility of preparing ocular inserts loaded with Poly-ε-Caprolactone (PCL) nanoparticles as a sustained ocular delivery system. Methods: First, Atorvastatin Calcium-Poly-ε-Caprolactone (ATC-PCL) nanoparticles were prepared and characterized. Then, the optimized nanoparticles were loaded within inserts formulated with Methylcellulose (MC) and Polyvinyl Alcohol (PVA) by a solvent casting technique and evaluated physically, for in-vitro drug release profile. Finally, an in-vivo study was performed on the selected formulation to prove non-irritability and sustained ocular anti-inflammatory efficacy compared with free drug-loaded ocuserts. Results: The results revealed (ATC-PCL) nanoparticles prepared with 0.5% pluronic F127 were optimized with 181.72±3.6 nm particle size, 0.12±0.02 (PDI) analysis, -27.4± 0.69 mV zeta potential and 62.41%±4.7% entrapment efficiency. Nanoparticles loaded ocuserts manifested compatibility between drug and formulation polymers. Moreover, formulations complied with average weight 0.055±0.002 to 0.143±0.023 mg, and accepted pH. ATC-PCL nanoparticles loaded inserts prepared by 5% MC showed more sustained, prolonged in-vitro release over 24h. In-vivo study emphasized non-irritability, ocular anti-inflammatory effectiveness represented by smaller lid closure scores, and statistically significant lowering in PMN count after 3h. Conclusion: These findings proposed a possibly simple, new and affordable price technique to prepare promising (ATC-PCL) nanoparticles loaded inserts to achieve sustained release with prolonged antiinflammatory efficacy.

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