USP5: Comprehensive insights into structure, function, biological and disease-related implications, and emerging therapeutic opportunities

A pathological missense mutation in the deubiquitinase USP5 leads to insensitivity to pain

Cav3.2 T-type calcium channels and their dysregulation by the deubiquitinase USP5 contribute to development of inflammatory and neuropathic pain. We report on a pediatric patient with a de novo heterozygous missense mutation R24W in USP5 who exhibits pain insensitivity. We created a CRISPR knock-in mouse harboring this mutation and performed detailed behavioral analyses in acute and chronic pain models. Heterozygous R24W mice of both sexes are resistant to acute pain and to thermal hypersensitivity in chronic inflammatory and neuropathic pain models. In contrast, only male R24W mice confer resistance to development of mechanical hypersensitivity. R24W mice lack upregulation of Cav3.2 and USP5 that is normally observed with CFA-induced inflammation. Moreover, mutant USP5 exhibits a dramatic reduction in enzymatic activity but stronger interactions with Cav3.2. Hence, R24W mutant USP5 is a critical regulator of chronic and acute pain states in humans by acting as a dominant-negative regulator of Cav3.2. Our data validate USP5 as a potential therapeutic target for chronic pain in humans.

Comprehensive insights of etiological drivers of hepatocellular carcinoma: Fostering targeted nano delivery to anti-cancer regimes

Hepatocellular carcinoma (HCC) stands as one of the most prevalent and deadliest malignancies on a global scale. Its complex pathogenesis arises from multifactorial etiologies, including viral infections, metabolic syndromes, and environmental carcinogens, all of which drive genetic and molecular aberrations in hepatocytes. This intricate condition is associated with multiple causative factors, resulting in the abnormal activation of various cellular and molecular pathways. Given that HCC frequently manifests within the context of a compromised or cirrhotic liver, coupled with the tendency of late-stage diagnoses, the overall prognosis tends to be unfavorable. Systemic therapy, especially conventional cytotoxic drugs, generally proves ineffective. Despite advancements in therapeutic interventions, conventional treatments such as chemotherapy often exhibit limited efficacy and substantial systemic toxicity. In this context, nanomedicine, particularly lipid-based nanoparticles (LNPs), has emerged as a promising strategy for enhancing drug delivery specificity and reducing adverse effects. This review provides a comprehensive overview of the molecular and metabolic underpinnings of HCC. Furthermore, we explored the role of lipid-based nano-formulations including liposomes, solid lipid nanoparticles, and nanostructured lipid carriers in targeted drug delivery for HCC. We have highlighted recent advances in LNP-based delivery approaches, FDA-approved drugs, and surface modification strategies to improve liver-specific delivery and therapeutic efficacy. It will provide a comprehensive summary of various treatment strategies, recent clinical advances, receptor-targeting strategies and the role of lipid composition in cellular uptake. The review concludes with a critical assessment of existing challenges and future prospects in nanomedicines-driven HCC therapy.

USP5 Stabilizes IKBKG Through Deubiquitination to Suppress Ferroptosis and Promote Growth in Non-small Cell Lung Cancer

Ferroptosis, a distinctive modality of cell mortality, has emerged as a critical regulator in non-small cell lung cancer (NSCLC). The deubiquitinating enzyme USP5 has established an oncogenic role in NSCLC. However, its biological relevance in NSCLC cell ferroptosis is currently unexplored. Expression analysis was performed by quantitative PCR (qPCR), immunohistochemistry (IHC) and immunoblotting. Animal xenograft studies were used to detect USP5's role in tumor growth. Cell proliferation, colony formation and apoptotic ratio were assessed by CCK-8, colony formation and flow cytometry assays, respectively. Cell ferroptosis was evaluated by gauging ROS, MDA, GSH, SOD, and Fe2+ contents. The USP5/IKBKG relationship and the ubiquitinated IKBKG were evaluated by Co-IP experiments. USP5 expression was elevated in human NSCLC. USP5 depletion suppressed NSCLC cell in vitro and in vivo growth and enhanced cell apoptosis. Moreover, USP5 depletion induced ferroptosis in NSCLC cell lines. Mechanistically, USP5 could enhance the stability of IKBKG protein through deubiquitination. Re-expression of IKBKG partially but significantly abolished USP5 depletion-mediated anti-growth and pro-ferroptosis effects in NSCLC cells. Our study demonstrates that USP5 suppresses ferroptosis and enhances growth in NSCLC cells by stabilizing IKBKG protein through deubiquitination. Targeting USP5 expression is an encouraging strategy to block NSCLC progression.

ANXA1 promotes intrahepatic cholangiocarcinoma proliferation and growth by regulating glutamine metabolism through GOT1 stabilization

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is a malignant tumor with a poor prognosis, marked by a postoperative recurrence rate of 50-60% and a 5-year survival rate of 8-30%. Abnormal tumor metabolism, particularly, amino acid metabolism, plays a key role in malignant progression. However, the molecular mechanisms linking amino acid metabolism to ICC progression remain unclear.

METHODS

Bioinformatics was used to identity the key amino acid metabolism related gene in ICC, qRT-PCR, western blotting and immunohistochemical (IHC) were used to detect the expression of ANXA1 in normal tissues or ICC tissues and cells at mRNA and protein levels. The effects of ANXA1 on the proliferation ability of ICC in vitro and in vivo were investigated using CCK8, cloning formation experiment, EdU, IHC, nude mice subcutaneous tumorigenesis model. Immunoprecipitation, mass spectrometry analysis, protein ubiquitin level detection test, immunofluorescence co-localization, and redox stress metabolite detection test were used to explore the metabolism-related regulatory mechanism of ANXA1.

RESULTS

we employed bioinformatics analysis to classify ICC into metabolic subgroups with distinct prognoses and identified the associated biomarker Annexin A1(ANXA1), whose high expression is correlated with poor prognosis and promotes ICC development. Mass spectrometry analysis revealed that ANXA1 interacts with the key enzyme in glutamine metabolism, glutamic-oxaloacetic transaminase 1(GOT1). Through in vitro and in vivo experiments, overexpressed ANXA1 stabilizes GOT1 by recruiting the deubiquitinase USP5. This stabilization enhances glutamine uptake, as well as the production of aspartate and glutamate, which in turn reduces oxidative stress, thereby promoting tumor cell growth. Moreover, knockdown of ANXA1 combined with glutamine uptake inhibition significantly suppressed ICC cell proliferation and Inhibited subcutaneous tumor formation and growth.

CONCLUSIONS

These results suggest that the ANXA1/USP5/GOT1 axis promotes glutamine metabolism and ICC proliferation and growth. Inhibiting ANXA1 alongside glutamine uptake inhibition offers a promising strategy for treating ICC.

mRNA decay pre-complex assembly drives timely cell-state transitions during differentiation

Complexes that control mRNA stability and translation promote timely cell-state transitions during differentiation by ensuring appropriate expression patterns of key developmental regulators. The Drosophila RNA-binding protein brain tumor (Brat) promotes the degradation of target transcripts during the maternal-to-zygotic transition in syncytial embryos and uncommitted intermediate neural progenitors (immature INPs). We identify ubiquitin-specific protease 5 (Usp5) as a candidate Brat interactor essential for the degradation of Brat target mRNAs. Usp5 promotes the formation of the Brat-deadenylase pre-complex in mitotic neural stem cells (neuroblasts) by facilitating Brat interactions with the scaffolding components of deadenylase complexes. The adaptor protein Miranda binds the RNA-binding domain of Brat, limiting its ability to bind target mRNAs in mitotic neuroblasts. Cortical displacement of Miranda activates Brat-deadenylase complex activity in immature INPs. We propose that the assembly of an enzymatically inactive and RNA-binding-deficient pre-complex poises mRNA degradation machineries for rapid activation, driving timely developmental transitions.

The deubiquitinase USP5 prevents accumulation of protein aggregates in cardiomyocytes

Protein homeostasis is crucial for maintaining cardiomyocyte (CM) function. Disruption of proteostasis results in accumulation of protein aggregates causing cardiac pathologies such as hypertrophy, dilated cardiomyopathy (DCM), and heart failure. Here, we identify ubiquitin-specific peptidase 5 (USP5) as a critical determinant of protein quality control (PQC) in CM. CM-specific loss of mUsp5 leads to the accumulation of polyubiquitin chains and protein aggregates, cardiac remodeling, and eventually DCM. USP5 interacts with key components of the proteostasis machinery, including PSMD14, and the absence of USP5 increases activity of the ubiquitin-proteasome system and autophagic flux in CMs. Cardiac-specific hUSP5 overexpression reduces pathological remodeling in pressure-overloaded mouse hearts and attenuates protein aggregate formation in titinopathy and desminopathy models. Since CMs from humans with end-stage DCM show lower USP5 levels and display accumulation of ubiquitinated protein aggregates, we hypothesize that therapeutically increased USP5 activity may reduce protein aggregates during DCM. Our findings demonstrate that USP5 is essential for ubiquitin turnover and proteostasis in mature CMs.

Development of Tetrahydroquinoline-Based Inhibitors for Chronic Pain

Chronic pain affects a substantial portion of the population, posing a significant health challenge. Current treatments often come with limitations and side effects, necessitating novel therapeutic approaches. Our study focuses on disrupting the Cav3.2-USP5 interaction as a strategy for chronic pain management. Through structure-activity relationship studies of a tetrahydroquinoline (THQ) scaffold, we identified a family of lead molecules that demonstrated potent inhibition of the Cav3.2-USP5 interaction. In vitro pharmacokinetic assessments and in vivo studies support the efficacy and drug-like properties of the lead compounds in mouse models of acute and chronic pain. Dependence on the Cav3.2 channels was validated in Cav3.2 null mice, consistent with the proposed mode of action of these small molecules. These findings provide a novel chronic pain treatment strategy, highlighting the potential of these small molecules for further development.

Unraveling the Immune Regulatory Functions of USP5: Implications for Disease Therapy

Ubiquitin-specific protease 5 (USP5) belongs to the ubiquitin-specific protease (USP) family, which uniquely recognizes unanchored polyubiquitin chains to maintain the homeostasis of monoubiquitin chains. USP5 participates in a wide range of cellular processes by specifically cleaving isopeptide bonds between ubiquitin and substrate proteins or ubiquitin itself. In the process of immune regulation, USP5 affects important cellular signaling pathways, such as NF-κB, Wnt/β-catenin, and IFN, by regulating ubiquitin-dependent protein degradation. These pathways play important roles in immune regulation and inflammatory responses. In addition, USP5 regulates the activity and function of immunomodulatory signaling pathways via the deubiquitination of key proteins, thereby affecting the activity of immune cells and the regulation of immune responses. In the present review, the structure and function of USP5, its role in immune regulation, and the mechanism by which USP5 affects the development of diseases by regulating immune signaling pathways are comprehensively overviewed. In addition, we also introduce the latest research progress of targeting USP5 in the treatment of related diseases, calling for an interdisciplinary approach to explore the therapeutic potential of targeting USP5 in immune regulation.

Post-transcriptional regulatory pre-complex assembly drives timely cell-state transitions during differentiation

Complexes that control mRNA stability and translation promote timely cell-state transitions during differentiation by ensuring appropriate expression patterns of key developmental regulators. The Drosophila RNA-binding protein Brain tumor (Brat) promotes degradation of target transcripts during the maternal-to-zygotic transition in syncytial embryos and in uncommitted intermediate neural progenitors (immature INPs). We identified Ubiquitin-specific protease 5 (Usp5) as a Brat interactor essential for the degradation of Brat target mRNAs in both cell types. Usp5 promotes Brat-dedadenylase pre-complex assembly in mitotic neural stem cells (neuroblasts) by bridging Brat and the scaffolding components of deadenylase complexes lacking their catalytic subunits. The adaptor protein Miranda binds the RNA-binding domain of Brat, limiting its ability to bind target mRNAs in mitotic neuroblasts. Cortical displacement of Miranda activates Brat-mediated mRNA decay in immature INPs. We propose that the assembly of an enzymatically inactive and RNA-binding-deficient pre-complex poises mRNA degradation machineries for rapid activation driving timely developmental transitions.