The Pellino1-PKCθ signaling axis is an essential target for improving anti-tumor CD8+ T-lymphocyte function

Tumoural Pellino-1 expression and Pellino-1-expressive cytotoxic T-cells are associated with poor prognosis in diffuse large B-cell lymphoma

Pellino-1 plays a role in regulating inflammation and immune responses, and its effects on tumours are complex, with different outcomes reported in various studies. Additionally, the role of Pellino-1 in diffuse large B-cell lymphoma (DLBCL) has not been thoroughly investigated. We aimed to examine the expression of Pellino-1 in tumour cells and tumour-infiltrating lymphocytes (TILs) separately and identify the clinicopathological significance of Pellino-1 expression in DLBCL. We evaluated Pellino-1 expression in 104 patients with DLBCL. The density of specific cell types was quantitatively analysed using digital image analysis after a multiplex immunofluorescence staining with Pellino-1, CD20, CD8, FOXP3, and PD-1. Pellino-1 expression was mostly observed in CD20+ tumour cells and CD8+ TILs. The high CD8+/Pellino-1+ group was significantly associated with the non-GCB subtype and higher numbers of Foxp3+ T-cells. Patients with high CD20+/Pellino-1+ and high CD8+/Pellino-1+ cell densities had significantly shorter event-free survival (EFS) rates. The multivariate Cox-regression analysis showed that CD20+/Pellino-1+ cell density and CD8+/Pellino-1+ cell density were independent poor prognostic factors for EFS. Furthermore, patients with low densities of both CD20+/Pellino-1+ and CD8+/Pellino-1+ cells demonstrated a prognosis superior to that of patients with high Pellino-1+ cell densities, either alone or in combination. Additionally, the multivariate analysis demonstrated that the combination of CD20+/Pellino-1+ and CD8+/Pellino-1+ cell densities was an independent prognostic factor for EFS and overall survival. Pellino-1 expression was observed in both tumour cells and TILs, particularly in cytotoxic T-cells, and was correlated with poor outcomes in DLBCL. Thus, Pellino-1 might have an oncogenic effect on DLBCL and might be a potential target for improving cytotoxic T-cell activity.

HNF4α ubiquitination mediated by Peli1 impairs FAO and accelerates pressure overload-induced myocardial hypertrophy

Impaired fatty acid oxidation (FAO) is a prominent feature of metabolic remodeling observed in pathological myocardial hypertrophy. Hepatocyte nuclear factor 4alpha (HNF4α) is closely associated with FAO in both cellular processes and disease conditions. Pellino 1 (Peli1), an E3 ligase containing a RING-like domain, plays a crucial role in catalyzing polyubiquitination of various substrates. In this study, we aimed to investigate the involvement of HNF4α and its ubiquitination, facilitated by Peli1, in FAO during pressure overload-induced cardiac hypertrophy. Peli1 systemic knockout mice (Peli1KO) display improved myocardial hypertrophy and cardiac function following transverse aortic constriction (TAC). RNA-seq analysis revealed that changes in gene expression related to lipid metabolism caused by TAC were reversed in Peli1KO mice. Importantly, both HNF4α and its downstream genes involved in FAO showed a significant increase in Peli1KO mice. We further used the antagonist BI6015 to inhibit HNF4α and delivered rAAV9-HNF4α to elevate myocardial HNF4α level, and confirmed that HNF4α inhibits the development of cardiac hypertrophy after TAC and is essential for the enhancement of FAO mediated by Peli1 knockout. In vitro experiments using BODIPY incorporation and FAO stress assay demonstrated that HNF4α enhances FAO in cardiomyocytes stimulated with angiotension II (Ang II), while Peli1 suppresses the effect of HNF4α. Mechanistically, immunoprecipitation and mass spectrometry analyses confirmed that Peli1 binds to HNF4α via its RING-like domain and promotes HNF4α ubiquitination at residues K307 and K309. These findings shed light on the underlying mechanisms contributing to impaired FAO and offer valuable insights into a promising therapeutic strategy for addressing pathological cardiac hypertrophy.

Biology of Pellino1: a potential therapeutic target for inflammation in diseases and cancers

Pellino1 (Peli1) is a highly conserved E3 Ub ligase that exerts its biological functions by mediating target protein ubiquitination. Extensive evidence has demonstrated the crucial role of Peli1 in regulating inflammation by modulating various receptor signaling pathways, including interleukin-1 receptors, Toll-like receptors, nuclear factor-κB, mitogen-activated protein kinase, and phosphoinositide 3-kinase/AKT pathways. Peli1 has been implicated in the development of several diseases by influencing inflammation, apoptosis, necrosis, pyroptosis, autophagy, DNA damage repair, and glycolysis. Peli1 is a risk factor for most cancers, including breast cancer, lung cancer, and lymphoma. Conversely, Peli1 protects against herpes simplex virus infection, systemic lupus erythematosus, esophageal cancer, and toxic epidermolysis bullosa. Therefore, Peli1 is a potential therapeutic target that warrants further investigation. This comprehensive review summarizes the target proteins of Peli1, delineates their involvement in major signaling pathways and biological processes, explores their role in diseases, and discusses the potential clinical applications of Peli1-targeted therapy, highlighting the therapeutic prospects of Peli1 in various diseases.

Ubiquitination Links DNA Damage and Repair Signaling to Cancer Metabolism

Changes in the DNA damage response (DDR) and cellular metabolism are two important factors that allow cancer cells to proliferate. DDR is a set of events in which DNA damage is recognized, DNA repair factors are recruited to the site of damage, the lesion is repaired, and cellular responses associated with the damage are processed. In cancer, DDR is commonly dysregulated, and the enzymes associated with DDR are prone to changes in ubiquitination. Additionally, cellular metabolism, especially glycolysis, is upregulated in cancer cells, and enzymes in this metabolic pathway are modulated by ubiquitination. The ubiquitin-proteasome system (UPS), particularly E3 ligases, act as a bridge between cellular metabolism and DDR since they regulate the enzymes associated with the two processes. Hence, the E3 ligases with high substrate specificity are considered potential therapeutic targets for treating cancer. A number of small molecule inhibitors designed to target different components of the UPS have been developed, and several have been tested in clinical trials for human use. In this review, we discuss the role of ubiquitination on overall cellular metabolism and DDR and confirm the link between them through the E3 ligases NEDD4, APC/C^CDH1, FBXW7, and Pellino1. In addition, we present an overview of the clinically important small molecule inhibitors and implications for their practical use.

Peli1 deletion in macrophages attenuates myocardial ischemia/reperfusion injury by suppressing M1 polarization

The polarization of macrophages to the M1 or M2 phenotype has a pivotal role in inflammatory response following myocardial ischemia/reperfusion injury. Peli1, an E3 ubiquitin ligase, is closely associated with inflammation and autoimmunity as an important regulatory protein in the Toll-like receptor signaling pathway. We aimed to explore the function of Peli1 in macrophage polarization under myocardial ischemia/reperfusion injury and elucidate the possible mechanisms. We show here that Peli1 is upregulated in peripheral blood mononuclear cells from patients with myocardial ischemia/reperfusion, which is correlated with myocardial injury and cardiac dysfunction. We also found that the proportion of M1 macrophages was reduced and myocardial infarct size was decreased, paralleling improvement of cardiac function in mice with Peli1 deletion in hematopoietic cells or macrophages. Macrophage Peli1 deletion lessened M1 polarization and reduced the migratory ability in vitro. Mechanistically, Peli1 contributed to M1 polarization by promoting K63-linked ubiquitination and nuclear translocation of IRF5. Moreover, Peli1 deficiency in macrophages reduced the apoptosis of cardiomyocytes in vivo and in vitro. Together, our study demonstrates that Peli1 deficiency in macrophages suppresses macrophage M1 polarization and alleviates myocardial ischemia/reperfusion injury by inhibiting the nuclear translocation of IRF5, which may serve as a potential intervention target for myocardial ischemia/reperfusion injury.

Comparative analysis of intestinal microbiota composition and transcriptome in diploid and triploid Carassius auratus

Polyploidy and the microbiome are crucial factors in how a host organism responds to disease. However, little is known about how triploidization and microbiome affect the immune response and disease resistance in the fish host. Therefore, this study aims to identify the relationship between intestinal microbiota composition, transcriptome changes, and disease resistance in triploid Carassius auratus (3nCC). In China's central Dongting lake water system, diploid (2nCC) and triploid Carassius auratus were collected, then 16S rRNA and mRNA sequencing were used to examine the microbes and gene expression in the intestines. 16S rRNA sequencing demonstrated that triploidization altered intestinal richness, as well as the diversity of commensal bacteria in 3nCC. In addition, the abundance of the genus Vibrio in 3nCC was increased compared to 2nCC (P < 0.05). Furthermore, differential expression analysis of 3nCC revealed profound up-regulation of 293 transcripts, while 324 were down-regulated. Several differentially expressed transcripts were related to the immune response pathway in 3nCC, including NLRP3, LY9, PNMA1, MR1, PELI1, NOTCH2, NFIL3, and NLRC4. Taken together, triploidization can alter bacteria composition and abundance, which can in turn result in changes in expression of genes. This study offers an opportunity for deciphering the molecular mechanism underlying disease resistance after triploidization.

T-cell exhaustion in immune-mediated inflammatory diseases: New implications for immunotherapy

Immune-mediated inflammatory diseases(IMIDs) are referred to as highly disabling chronic diseases affecting different organs and systems. Inappropriate or excessive immune responses with chronic inflammation are typical manifestations. Usually in patients with chronic infection and cancer, due to long-term exposure to persistent antigens and inflammation microenvironment, T-cells are continuously stimulated and gradually differentiate into an exhausted state. Exhausted T-cells gradually lose effector function and characteristics of memory T-cells. However, existing studies have found that exhausted T-cells are not only present in the infection and tumor environment, but also in autoimmunity, and are associated with better prognosis of IMIDs. This suggests new prospects for the application of this reversible process of T-cell exhaustion in the treatment of IMID. This review will focus on the research progress of T-cell exhaustion in several IMIDs and its potential application for diagnosis and treatment in IMIDs.

The E3 Ubiquitin Ligase Peli1 Deficiency Promotes Atherosclerosis Progression

Background: Atherosclerosis is a chronic inflammatory vascular disease and the main cause of death and morbidity. Emerging evidence suggests that ubiquitination plays an important role in the pathogenesis of atherosclerosis including control of vascular inflammation, vascular smooth muscle cell (VSMC) function and atherosclerotic plaque stability. Peli1 a type of E3 ubiquitin ligase has emerged as a critical regulator of innate and adaptive immunity, however, its role in atherosclerosis remains to be elucidated. Methods: Apoe^−/− mice and Peli1-deficient Apoe^−/− Peli1^−/− mice were subject to high cholesterol diet. Post sacrifice, serum was collected, and atherosclerotic plaque size and parameters of atherosclerotic plaque stability were evaluated. Immunoprofiling and foam cell quantification were performed. Results: Peli1 deficiency does not affect atherosclerosis lesion burden and cholesterol levels, but promotes VSMCs foam cells formation, necrotic core expansion, collagen, and fibrous cap reduction. Apoe^−/− Peli1^−/− mice exhibit a storm of inflammatory cytokines, expansion of Th1, Th1, Th17, and Tfh cells, a decrease in regulatory T and B cells and induction of pro-atherogenic serum level of IgG2a and IgE. Conclusions: In the present study, we uncover a crucial role for Peli1 in atherosclerosis as an important regulator of inflammation and VSMCs phenotypic modulation and subsequently atherosclerotic plaque destabilization.