PAQR3 modulates H3K4 trimethylation by spatial modulation of the regulatory subunits of COMPASS-like complexes in mammalian cells

Initial Characterization of WDR5B Reveals a Role in the Proliferation of Retinal Pigment Epithelial Cells

The chromatin-associated protein WDR5 has been widely studied due to its role in histone modification and its potential as a pharmacological target for the treatment of cancer. In humans, the protein with highest sequence homology to WDR5 is encoded by the retrogene WDR5B, which remains unexplored. Here, we used CRISPR-Cas9 genome editing to generate WDR5B knockout and WDR5B-FLAG knock-in cell lines for further characterization. In contrast to WDR5, WDR5B exhibits low expression in pluripotent cells and is upregulated upon neural differentiation. Loss or shRNA depletion of WDR5B impairs cell growth and increases the fraction of non-viable cells in proliferating retinal pigment epithelial (RPE) cultures. CUT&RUN chromatin profiling in RPE and neural progenitors indicates minimal WDR5B enrichment at established WDR5 binding sites. These results suggest that WDR5 and WDR5B exhibit several divergent biological properties despite sharing a high degree of sequence homology.

PAQR3 inhibits proliferation and aggravates ferroptosis in acute lymphoblastic leukemia through modulation Nrf2 stability

INTRODUCTION

Acute lymphoblastic leukemia (ALL) is a usual hematological tumor, which was featured by malignant proliferation of lymphoid progenitor cells. Many important factors participate into the regulation of ALL, including proteins. PAQR3 (also named RKTG) has been proved to take part in many human cancers by acting as a tumor suppressor. PAQR3 has bee n shown to repress human leukemia cells proliferation and induce cell apoptosis, but its role and relevant regulatory mechanism on cell proliferation and ferroptosis in ALL needs more exploration.

METHODS

The genes expression was detected through quantitative reverse transcription polymerase chain reaction (mRNA) or western blot (protein). The cell proliferation was assessed through Cell Counting Kit-8 and 5-ethynyl-2-deoxyuridine assays. The levels of MDA, DCF, and intracellular free Fe in ALL cells were tested through the commercial kits. The cell apoptosis was determined through flow cytometry analysis. The binding ability of PAQR3 and nuclear factor erythroid 2-related factor 2 (Nrf2) was verified through pull down assay.

RESULTS

PAQR3 expression was firstly assessed in ALL patients and cell lines, and discovered to be downregulated. It was verified that PAQR3 suppressed ALL cells proliferation. Further experiments proved that PAQR3 aggravates ferroptosis in ALL. In addition, AQR3 bound with Nrf2, and modulated its expression through ubiquitination in ALL. Finally, through rescue assays, it was demonstrated that Nrf2 overexpression reversed the effects of PAQR3 on cell proliferation and ferroptosis.

CONCLUSION

Findings from our work uncovered that PAQR3 inhibited proliferation and aggravated ferroptosis in ALL through modulation Nrf2 stability. This study suggested that PAQR3 may serve as an effective biological marker for ALL treatment.

Investigation of the gene co-expression network and hub genes associated with acute mountain sickness

Background

Acute mountain sickness has become a heavily researched topic in recent years. However, the genetic mechanism and effects have not been elucidated. Our goal is to construct a gene co-expression network to identify the key modules and hub genes associated with high altitude hypoxia.

Results

The GSE46480 dataset of rapidly transported healthy adults with acute mountain sickness was selected and analyzed by weighted gene co-expression network analysis (WGCNA) to construct a co-expression network. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of the data set were carried out using Database for Annotation Visualization and Integrated Discovery (DAVID), and the hub genes were selected. We found that the turquoise module was most significantly correlated with acute mountain sickness. The functional enrichment analysis showed that the turquoise module was related to the apoptotic process, protein transport, and translation processes. The metabolic pathway analysis identified hsa03010:ribosome and hsa04144:endocytosis as the most important pathways in the turquoise module. Ten top 10 hub genes (MRPL3, PSMC6, AIMP1, HAT1, DPY30, ATP5L, COX7B, UQCRB, DPM1, and COMMD6) for acute mountain sickness were identified.

Conclusion

One module and 10 hub genes were identified, which were related to acute mountain sickness. The reference provided by this module may help to elucidate the mechanism of acute mountain sickness. In addition, the hub genes may be used in the future as a biomarker and therapeutic target for accurate diagnosis and treatment.

Characterization of the Golgi scaffold protein PAQR3, and its role in tumor suppression and metabolic pathway compartmentalization

The Golgi apparatus is critical in the compartmentalization of signaling cascades originating from the cytoplasmic membrane and various organelles. Scaffold proteins, such as progestin and adipoQ receptor (PAQR)3, specifically regulate this process, and have recently been identified in the Golgi apparatus. PAQR3 belongs to the PAQR family, and was recently described as a tumor suppressor. Accumulating evidence demonstrates PAQR3 is downregulated in different cancers to suppress its inhibitory effects on malignant potential. PAQR3 functions biologically through the pathological regulation of altered signaling pathways. Significant cell proliferation networks, including Ras proto-oncogene (Ras)/mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), insulin, and vascular endothelial growth factor, are closely controlled by PAQR3 for physiologically relevant effects. Meanwhile, genetic/epigenetic susceptibility and environmental factors, may have functions in the downregulation of PAQR3 in human cancers. This study aimed to assess the subcellular localization of PAQR3 and determine its topological features and functional domains, summarizing its effects on cell signaling compartmentalization. The pathophysiological functions of PAQR3 in cancer pathogenesis, metabolic diseases, and developmental ailments were also highlighted.

PAQR3 Regulates Endoplasmic Reticulum-to-Golgi Trafficking of COPII Vesicle via Interaction with Sec13/Sec31 Coat Proteins

Endoplasmic reticulum (ER)-to-Golgi anterograde transport is driven by COPII vesicles mainly composed of a Sec23/Sec24 inner shell and a Sec13/Sec31 outer cage. How COPII vesicles are tethered to the Golgi is not completely understood. We demonstrated here that PAQR3 can facilitate tethering of COPII vesicles to the Golgi. Proximity labeling using PAQR3 fused with APEX2 identified that many proteins involved in intracellular transport are in close proximity to PAQR3. ER-to-Golgi trafficking of N-acetylgalactosaminyltransferase-2 on removal of brefeldin A is delayed by PAQR3 deletion. RUSH assay also revealed that ER-to-Golgi trafficking is affected by PAQR3. The N-terminal end of PAQR3 can interact with the WD domains of Sec13 and Sec31A. PAQR3 enhances Golgi localization of Sec13 and Sec31A. Furthermore, PAQR3 is localized in the ERGIC and cis-Golgi structures, the acceptor sites for COPII vesicles. Taken together, our study uncovers a role for PAQR3 as a player in regulating ER-to-Golgi transport of COPII vesicles.

[Expression and Clinical Significance of Progesterone and Adiponectin Receptor Family Member 3 in Lung Cancer]

BACKGROUND

Progesterone and adiponectin receptor family member 3 (PAQR3) is a recently discovered tumor suppressor gene, which affects the development of a tumor by inhibiting cell proliferation, cell malignant transformation, angiogenesis, and tumor metastasis. This study investigates the expression of PAQR3 in lung cancer and its clinical significance.

METHODS

A total of 106 patients with lung cancer received surgical treatment in hospital, and adjacent normal tissues of these patients were utilized as control group. The diagnosis of all patients was confirmed through clinical pathology. The expression of PAQR3 protein was detected by immunohistochemistry in lung cancer and adjacent normal tissues. The clinical significance of its expression was also investigated.

RESULTS

The positive expression rate of PAQR3 protein in lung cancer was lower than that in adjacent normal tissues (P<0.01). The positive expression rate of PAQR3 protein was unrelated to age, tumor size, and gender, but it exhibited a significant relationship with the pathological type and differentiation, TNM staging, and lymph node metastasis (P<0.05). Kaplan-Meier survival analysis showed that the five-year survival rate of patients with PAQR3 protein positive expression was higher than that in patients with negative expression (P=0.026).

CONCLUSIONS

The expression of PAQR3 protein significantly decreased in lung cancer, indicating that PAQR3 protein plays an important role in the pathogenesis of PAQR3 in lung cancer.

Unique Role of the WD-40 Repeat Protein 5 (WDR5) Subunit within the Mixed Lineage Leukemia 3 (MLL3) Histone Methyltransferase Complex

The MLL3 (mixed lineage leukemia 3) protein is a member of the human SET1 family of histone H3 lysine 4 methyltransferases and contains the conserved WDR5 interaction (Win) motif and the catalytic suppressor of variegation, enhancer of zeste, trithorax (SET) domain. The human SET1 family includes MLL1-4 and SETd1A/B, which all interact with a conserved subcomplex containing WDR5, RbBP5, Ash2L, and DPY-30 (WRAD) to form the minimal core complex required for full methyltransferase activity. However, recent evidence suggests that the WDR5 subunit may not be utilized in an identical manner within all SET1 family core complexes. Although the roles of WDR5 within the MLL1 core complex have been extensively studied, not much is known about the roles of WDR5 in other SET1 family core complexes. In this investigation, we set out to characterize the roles of the WDR5 subunit in the MLL3 core complex. We found that unlike MLL1, the MLL3 SET domain assembles with the RbBP5/Ash2L heterodimer independently of the Win motif-WDR5 interaction. Furthermore, we observed that WDR5 inhibits the monomethylation activity of the MLL3 core complex, which is dependent on the Win motif. We also found evidence suggesting that the WRAD subcomplex catalyzes weak H3K4 monomethylation within the context of the MLL3 core complex. Furthermore, solution structures of the MLL3 core complex assembled with and without WDR5 by small angle x-ray scattering show similar overall topologies. Together, this work demonstrates a unique role for WDR5 in modulating the enzymatic activity of the MLL3 core complex.