Hu Antigen R (HuR) Protein Structure, Function and Regulation in Hepatobiliary Tumors

Human antigen R: Exploring its inflammatory response impact and significance in cardiometabolic disorders

RNA-binding proteins (RBPs) play a crucial role in the regulation of posttranscriptional RNA networks, which can undergo dysregulation in many pathological conditions. Human antigen R (HuR) is a highly researched RBP that plays a crucial role as a posttranscriptional regulator. HuR plays a crucial role in the amplification of inflammatory signals by stabilizing the messenger RNA of diverse inflammatory mediators and key molecular players. The noteworthy correlations between HuR and its target molecules, coupled with the remarkable impacts reported on the pathogenesis and advancement of multiple diseases, position HuR as a promising candidate for therapeutic intervention in diverse inflammatory conditions. This review article examines the significance of HuR as a member of the RBP family, its regulatory mechanisms, and its implications in the pathophysiology of inflammation and cardiometabolic illnesses. Our objective is to illuminate potential directions for future research and drug development by conducting a comprehensive analysis of the existing body of research on HuR.

SUMOylation controls Hu antigen R posttranscriptional activity in liver cancer

The posttranslational modification of proteins critically influences many biological processes and is a key mechanism that regulates the function of the RNA-binding protein Hu antigen R (HuR), a hub in liver cancer. Here, we show that HuR is SUMOylated in the tumor sections of patients with hepatocellular carcinoma in contrast to the surrounding tissue, as well as in human cell line and mouse models of the disease. SUMOylation of HuR promotes major cancer hallmarks, namely proliferation and invasion, whereas the absence of HuR SUMOylation results in a senescent phenotype with dysfunctional mitochondria and endoplasmic reticulum. Mechanistically, SUMOylation induces a structural rearrangement of the RNA recognition motifs that modulates HuR binding affinity to its target RNAs, further modifying the transcriptomic profile toward hepatic tumor progression. Overall, SUMOylation constitutes a mechanism of HuR regulation that could be potentially exploited as a therapeutic strategy for liver cancer.

Alternative splicing and related RNA binding proteins in human health and disease

Alternative splicing (AS) serves as a pivotal mechanism in transcriptional regulation, engendering transcript diversity, and modifications in protein structure and functionality. Across varying tissues, developmental stages, or under specific conditions, AS gives rise to distinct splice isoforms. This implies that these isoforms possess unique temporal and spatial roles, thereby associating AS with standard biological activities and diseases. Among these, AS-related RNA-binding proteins (RBPs) play an instrumental role in regulating alternative splicing events. Under physiological conditions, the diversity of proteins mediated by AS influences the structure, function, interaction, and localization of proteins, thereby participating in the differentiation and development of an array of tissues and organs. Under pathological conditions, alterations in AS are linked with various diseases, particularly cancer. These changes can lead to modifications in gene splicing patterns, culminating in changes or loss of protein functionality. For instance, in cancer, abnormalities in AS and RBPs may result in aberrant expression of cancer-associated genes, thereby promoting the onset and progression of tumors. AS and RBPs are also associated with numerous neurodegenerative diseases and autoimmune diseases. Consequently, the study of AS across different tissues holds significant value. This review provides a detailed account of the recent advancements in the study of alternative splicing and AS-related RNA-binding proteins in tissue development and diseases, which aids in deepening the understanding of gene expression complexity and offers new insights and methodologies for precision medicine.

Unraveling the Role of RNA-Binding Proteins, with a Focus on RPS5, in the Malignant Progression of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) represents a major global health concern, demanding a thorough understanding of its molecular mechanisms for effective therapeutic strategies. RNA-binding proteins (RBPs) play critical roles in post-transcriptional gene regulation, with their dysregulation increasingly recognized as a hallmark of various cancers. However, the specific contributions of RBPs to HCC pathogenesis and prevention remain incompletely understood. In this study, we systematically conducted an examination of the expression profiles and clinical relevance of RBPs in 556 clinical samples from well-established cohorts. Through comprehensive analyses, a subset of RBPs exhibiting significant overexpression in HCC was identified, establishing a noteworthy correlation between their aberrant expression and HCC progression. Furthermore, 40S ribosomal protein S5 (RPS5), a ribosomal protein, emerged as a potential key contributor in HCC progression. Rigorous analyses established a correlation between elevated RPS5 expression and advanced clinicopathological features, suggesting its potential as a prognostic biomarker. Experiments further confirmed the impact of RPS5 on pivotal cellular processes implicated in cancer progression, including cell proliferation and metastasis. Further mechanistic studies unveiled the potential of RPS5 to activate the cell cycle by binding to key molecules involved in the pathway, thereby promoting the malignant progression of HCC. Additionally, our analysis of the etiology behind RPS5 overexpression in HCC posited it as an outcome of transcriptional regulation by the transcription factors Nuclear Respiratory Factor 1 (NRF1) and MYC-associated zinc finger protein (MAZ). In conclusion, our study contributes to the growing evidence elucidating the intricate involvement of RBPs, exemplified by RPS5, in the malignant progression of HCC. The integration of genomic, transcriptomic, and functional analyses provides a comprehensive understanding of the regulatory mechanisms associated with RPS5 in HCC. This comprehensive analysis not only advances our knowledge of the molecular drivers behind HCC but also highlights the potential therapeutic relevance of targeting RBPs and their regulatory network for the development of more effective treatment strategies.

RNA-binding proteins in metabolic-associated fatty liver disease (MAFLD): From mechanism to therapy

Metabolic-associated fatty liver disease (MAFLD) is the most common chronic liver disease globally and seriously increases the public health burden, affecting approximately one quarter of the world population. Recently, RNA binding proteins (RBPs)-related pathogenesis of MAFLD has received increasing attention. RBPs, vividly called the gate keepers of MAFLD, play an important role in the development of MAFLD through transcription regulation, alternative splicing, alternative polyadenylation, stability and subcellular localization. In this review, we describe the mechanisms of different RBPs in the occurrence and development of MAFLD, as well as list some drugs that can improve MAFLD by targeting RBPs. Considering the important role of RBPs in the development of MAFLD, elucidating the RNA regulatory networks involved in RBPs will facilitate the design of new drugs and biomarkers discovery.

Potential Synergistic Supplementation of NAD+ Promoting Compounds as a Strategy for Increasing Healthspan

Disrupted biological function, manifesting through the hallmarks of aging, poses one of the largest threats to healthspan and risk of disease development, such as metabolic disorders, cardiovascular ailments, and neurodegeneration. In recent years, numerous geroprotectors, senolytics, and other nutraceuticals have emerged as potential disruptors of aging and may be viable interventions in the immediate state of human longevity science. In this review, we focus on the decrease in nicotinamide adenine dinucleotide (NAD+) with age and the supplementation of NAD+ precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), in combination with other geroprotective compounds, to restore NAD+ levels present in youth. Furthermore, these geroprotectors may enhance the efficacy of NMN supplementation while concurrently providing their own numerous health benefits. By analyzing the prevention of NAD+ degradation through the inhibition of CD38 or supporting protective downstream agents of SIRT1, we provide a potential framework of the CD38/NAD+/SIRT1 axis through which geroprotectors may enhance the efficacy of NAD+ precursor supplementation and reduce the risk of age-related diseases, thereby potentiating healthspan in humans.