Platelet-mediated circulating tumor cell evasion from natural killer cell killing through immune checkpoint CD155-TIGIT.

BACKGROUND AND AIMS: Circulating tumor cells (CTCs) are precursors of cancer metastasis. However, how CTCs evade immunosurveillance during hematogenous dissemination remains unclear. APPROACH AND RESULTS: We identified CTC-platelet adhesions by single-cell RNA sequencing and multiplex immunofluorescence of blood samples from multiple cancer types. Clinically, CTC-platelet aggregates were associated with significantly shorter progression-free survival and overall survival in patients with HCC. In vitro, ex vivo, and in vivo assays demonstrated direct platelet adhesions gifted cancer cells with an evasive ability from NK cell killing by upregulating inhibitory checkpoint CD155 (PVR cell adhesion molecule), therefore facilitating distant metastasis. Mechanistically, CD155 was transcriptionally regulated by the FAK/JNK/c-Jun cascade in a platelet contact-dependent manner. Further competition assays and cytotoxicity experiments revealed that CD155 on CTCs inhibited NK-cell cytotoxicity only by engaging with immune receptor TIGIT, but not CD96 and DNAM1, another 2 receptors for CD155. Interrupting the CD155-TIGIT interactions with a TIGIT antibody restored NK-cell immunosurveillance on CTCs and markedly attenuated tumor metastasis. CONCLUSIONS: Our results demonstrated CTC evasion from NK-cell-mediated innate immunosurveillance mainly through immune checkpoint CD155-TIGIT, potentially offering an immunotherapeutic strategy for eradicating CTCs.

Optimizing of a suitable protocol for isolating tissue-derived extracellular vesicles and profiling small RNA patterns in hepatocellular carcinoma.

BACKGROUND: Extracellular vesicles (EVs) facilitate cell-cell interactions in the tumour microenvironment. However, standard and efficient methods to isolate tumour tissue-derived EVs are lacking, and their biological functions remain elusive. METHODS: To determine the optimal method for isolating tissue-derived EVs, we compared the characterization and concentration of EVs obtained by three previously reported methods using transmission electron microscopy, nanoparticle tracking analysis, and nanoflow analysis (Nanoflow). Additionally, the differential content of small RNAs, especially tsRNAs, between hepatocellular carcinoma (HCC) and adjacent normal liver tissues (ANLTs)-derived EVs was identified using Arraystar small RNA microarray. The targets of miRNAs and tsRNAs were predicted, and downstream functional analysis was conducted using Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, non-negative matrix factorization and survival prediction analysis. RESULTS: A differential centrifugation-based protocol without cell cultivation (NC protocol) yielded higher EV particles and higher levels of CD9+ and CD63+ EVs compared with other isolation protocols. Interestingly, the NC protocol was also effective for isolating frozen tissue-derived EVs that were indistinguishable from fresh tissue. HCC tissues showed significantly higher EV numbers compared with ANLTs. Furthermore, we identified different types of small RNAs in HCC tissue-derived EVs, forming a unique multidimensional intercellular communication landscape that can differentiate between HCC and ANLTs. ROC analysis further showed that the combination of the top 10 upregulated small RNAs achieved better diagnostic performance (AUC = .950 [.895-1.000]). Importantly, most tsRNAs in HCC tissue-derived EVs were downregulated and mitochondria-derived, mainly involving in lipid-related metabolic reprogramming. CONCLUSION: The NC protocol was optimal for isolating EVs from HCC, especially from frozen tissues. Our study emphasized the different roles of small-RNA in regulating the HCC ecosystem, providing insights into HCC progression and potential therapeutic targets.

The eEF1A protein in cancer: Clinical significance, oncogenic mechanisms, and targeted therapeutic strategies.

Eukaryotic elongation factor 1A (eEF1A) is among the most abundant proteins in eukaryotic cells. Evolutionarily conserved across species, eEF1A is in charge of translation elongation for protein biosynthesis as well as a plethora of non-translational moonlighting functions for cellular homeostasis. In malignant cells, however, eEF1A becomes a pleiotropic driver of cancer progression via a broad diversity of pathways, which are not limited to hyperactive translational output. In the past decades, mounting studies have demonstrated the causal link between eEF1A and carcinogenesis, gaining deeper insights into its multifaceted mechanisms and corroborating its value as a prognostic marker in various cancers. On the other hand, an increasing number of natural and synthetic compounds were discovered as anticancer eEF1A-targeting inhibitors. Among them, plitidepsin was approved for the treatment of multiple myeloma whereas metarrestin was currently under clinical development. Despite significant achievements in these two interrelated fields, hitherto there lacks a systematic examination of the eEF1A protein in the context of cancer research. Therefore, the present work aims to delineate its clinical implications, molecular oncogenic mechanisms, and targeted therapeutic strategies as reflected in the ever expanding body of literature, so as to deepen mechanistic understanding of eEF1A-involved tumorigenesis and inspire the development of eEF1A-targeted chemotherapeutics and biologics.

Formyl peptide receptor 2 activation by mitochondrial formyl peptides stimulates the neutrophil proinflammatory response via the ERK pathway and exacerbates ischemia-reperfusion injury.

BACKGROUND: Ischemia-reperfusion injury (IRI) is an inevitable process in renal transplantation that significantly increases the risk of delayed graft function, acute rejection, and even graft loss. Formyl peptide receptor 2 (FPR2) is an important receptor in multiple septic and aseptic injuries, but its functions in kidney IRI are still unclear. This study was designed to reveal the pathological role of FPR2 in kidney IRI and its functional mechanisms. METHODS: To explore the mechanism of FPR2 in kidney IRI, the model rats were sacrificed after IRI surgery. Immunofluorescence, enzyme-linked immunosorbent assays, and western blotting were used to detect differences in the expression of FPR2 and its ligands between the IRI and control groups. WRW4 (WRWWWW-NH2), a specific antagonist of FPR2, was administered to kidney IRI rats. Kidney function and pathological damage were detected to assess kidney injury and recovery. Flow cytometry was used to quantitatively compare neutrophil infiltration among the experimental groups. Mitochondrial formyl peptides (mtFPs) were synthesized and administered to primary rat neutrophils together with the specific FPR family antagonist WRW4 to verify our hypothesis in vitro. Western blotting and cell function assays were used to examine the functions and signaling pathways that FPR2 mediates in neutrophils. RESULTS: FPR2 was activated mainly by mtFPs during the acute phase of IRI, mediating neutrophil migration and reactive oxygen species production in the rat kidney through the ERK1/2 pathway. FPR2 blockade in the early phase protected rat kidneys from IRI. CONCLUSIONS: mtFPs activated FPR2 during the acute phase of IRI and mediated rat kidney injury by activating the migration and reactive oxygen species generation of neutrophils through the ERK1/2 pathway.

Spatiotemporal changes of ecological environment quality and climate drivers in Zoige Plateau.

Ecological environment is the essential material basis of human survival and connects regional economy with socially sustainable development. However, climate changes characterized by global climate warming have caused a series of ecological environmental problems in recent years. Few studies have discussed various climate factors affecting the ecological environment, and the spatial non-stationary effects of different climate factors on the ecological environment are still unclear. Dynamically monitoring ecological environment changes in fragile areas and identifying its climate-driving mechanism are essential for ecological protection and environmental repair. Taking Zoige Plateau as a case, this paper simulated the eco-environmental quality during 1987-2020 using remote sensing data, utilized Geodetector method to identify the contributions of various climate drivers to ecological environment quality, and then adopted the Geographically Weighted Regression model to explore the spatial non-stationary impacts of climate factors on ecological environment quality. The results showed that the ecological quality in the middle regions of the Zoige Plateau was slightly better than in the surrounding marginal areas. For the whole area of Zoige Plateau, the average ecological environment quality index was 54.92, 53.99, 56.17, 57.88, 63.44, 56.93, 59.43, and 59.76 in 1987, 1992, 1997, 2001, 2006, 2013, 2016 and 2020, respectively, which indicated that eco-environmental quality witnessed several fluctuations during the study period but showed a generally increasing trend. Among five climate factors, the temperature was the dominant climate factor affecting the ecological environment quality (q value: 0.11-0.19), sunshine duration (0.03-0.17), wind speed (0.03-0.11), and precipitation (0.03-0.08) were the main climate drivers, while the explanatory power of relative humidity to ecological environment quality was relatively small. Such various climate factors impacting the ecological environment quality demonstrated distinct spatial non-stationary and the range of driving impact varied with time. Temperature, sunshine duration, wind speed, and relative humidity promoted ecological environment quality in most regions (regression coefficients > 0), while precipitation mainly had a negative inhibitory impact (regression coefficients < 0). Meanwhile, the greater impacts of these five climate factors were concentrated in high-elevation regions of the south and west or the northern areas. The appropriate enhancement of climate warming and air humidity was beneficial to the improvement of the ecological environment, but the excessive precipitation would result in landslides and exhibit inhibition of vegetation growth. Therefore, selecting cold-tolerant herbs and shrubs, and strengthening climate monitoring and early warning systems (such as drought and excessive precipitation) are essential for ecological restoration.

Integration of transcriptomics and metabolomics reveals pathways involved in MDSC supernatant attenuation of TGF-ß1-induced myofibroblastic differentiation of mesenchymal stem cells.

Overexposure to transforming growth factor b1 (TGF-ß1) induces myofibroblastic differentiation of mesenchymal stem cells (MSCs), which could be attenuated by myeloid-derived suppressor cell (MDSC) supernatant. However, the promyofibroblastic effects of TGF-ß1 and the antimyofibroblastic effects of MDSC supernatant in MSCs have not been fully elucidated. To further clarify the latent mechanism and identify underlying therapeutic targets, we used an integrative strategy combining transcriptomics and metabolomics. Bone marrow MSCs were collected 24 h following TGF-ß1 and MDSC supernatant treatment for RNA sequencing and untargeted metabolomic analysis. The integrated data were then analyzed to identify significant gene-metabolite correlations. Differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) were assessed by Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses for exploring the mechanisms of myofibroblastic differentiation of MSCs. The integration of transcriptomic and metabolomic data highlighted significantly coordinated changes in glycolysis/gluconeogenesis and purine metabolism following TGF-ß1 and MDSC supernatant treatment. By combining transcriptomic and metabolomic analyses, this study showed that glycolysis/gluconeogenesis and purine metabolism were essential for the myofibroblastic differentiation of MSCs and may serve as promising targets for mechanistic research and clinical practice in the treatment of fibrosis by MDSC supernatant.

Identification of HGD and GSTZ1 as Biomarkers Involved Metabolic Reprogramming in Kidney Renal Clear Cell Carcinoma.

Kidney renal clear cell carcinoma (KIRC) with poor prognosis is the main histological subtype of renal cell carcinoma, accounting for more than 80% of patients. Most patients are diagnosed at an advanced stage due to being asymptomatic early on. Advanced KIRC has an extremely poor prognosis due to its inherent resistance to radiotherapy and chemotherapy. Therefore, a comprehensive understanding of the molecular mechanisms of KIRC and the development of effective early diagnostic and therapeutic strategies is urgently needed. In this study, we aimed to identify the prognosis-related biomarker and analyzed its relationship with tumor progression. Metabolic changes are an important feature of kidney cancer, where the reduction of fumarate allows us to target the tyrosine metabolic pathway. The homogentisate 1,2-dioxygenase (HGD) and glutathione S-transferase zeta 1 (GSTZ1) related with prognosis of KIRC was identified through bioinformatics analysis based on The Cancer Genome Atlas (TCGA) databases. Mechanistically, we found that decreased HGD and GSTZ1 promote aerobic glycolysis in KIRC, coordinate the balance of amino acid metabolism and energy metabolism in tumor cells, and ultimately activate the tumor cell cycle and tumor progression. In summary, we identified the tyrosine metabolizing enzymes HGD and GSTZ1 as biomarkers of KIRC, which will further the understanding of the tumor metabolism profile, provide novel strategies and theoretical support for diagnosing and treating KIRC and as referential for future clinical research.

Single-cell Sequencing in the Field of Stem Cells.

Variation and heterogeneity between cells are the basic characteristics of stem cells. Traditional sequencing analysis methods often cover up this difference. Single-cell sequencing technology refers to the technology of high-throughput sequencing analysis of genomes at the single-cell level. It can effectively analyze cell heterogeneity and identify a small number of cell populations. With the continuous progress of cell sorting, nucleic acid extraction and other technologies, single-cell sequencing technology has also made great progress. Encouraging new discoveries have been made in stem cell research, including pluripotent stem cells, tissue-specific stem cells and cancer stem cells. In this review, we discuss the latest progress and future prospects of single-cell sequencing technology in the field of stem cells.

The interaction between Vav1 and EBNA1 promotes survival of Burkitt's lymphoma cells by down-regulating the expression of Bim.

Vav1 is a guanine nucleotide exchange factor (GEF) predominantly expressed in hematopoietic cells, and functions in the development and antigen-stimulated response of lymphocytes. Burkitt's lymphoma (BL) is characterized as transformed B cell lymphoma, and is highly associated with Epstein-Barr virus (EBV). EBV nuclear antigen 1 (EBNA1) is the only viral protein expressed across all three types of latency and essential for the persistence of EBV genome. It is not clear yet how EBNA1 contributes to the growth advantage of latently infected cells such as in EBV+ lymphoma B cells. Here, we reported that Vav1 interacts with EBNA1 via its C-terminal SH3 domain. This interaction suppresses the expression of a pro-apoptotic Bcl-2 family member, Bim, resulting in the resistance of the BL cells to apoptotic inductions. Our data uncovered Vav1 as a novel target for EBNA1, and suggested a pro-survival role of Vav1 in the pathogenesis of EBV associated BLs.

Ac4GlcNAcF3, an OGT-tolerated but OGA-resistant regulator for O-GlcNAcylation.

O-Linked N-acetylglucosamine (O-GlcNAc) is an abundant posttranslationalmonosaccaride-modification found on Ser or Thr residues of intracellular proteins in most eukaryotes. The dynamic nature of O-GlcNAc has enabled researchers to modulate the stoichiometry of O-GlcNAc on proteins in order to investigate its function. Cell permeable small moleculars have proven invaluable tools to increase O-GlcNAc levels. Herein, using in vitro substrate screening, we identified GlcNAcF3 as an OGT-accepted but OGA-resistant sugar mimic. Cellular experiments with cell-permeable peracetylated-GlcNAcF3 (Ac4GlcNAcF3) displayed that Ac4GlcNAcF3 was a potent tool to increase O-GlcNAc levels in several cell lines. Further, NIH3T3 cells interfered with OGT (siOGT) showed significant decreasing of O-GlcNAc levels with Ac4GlcNAcF3 treatment, indicating O-GlcNAcF3 was an OGT-dependent modification. In addition, cellular toxic assay confirmed O-GlcNAcF3 production has no significant effect on cell proliferation or viability. Thus, Ac4GlcNAcF3 represents a safe and dual regulator for both OGT and OGA, which will benefit the study of O-GlcNAc.

Detection and identification of O-GlcNAc-modified proteins using 6-azido-6-deoxy-N-acetyl-galactosamine.

An unnatural monosaccharide with a C6-azide, Ac36AzGalNAc, has been developed as a potent and selective probe for O-GlcNAc-modified proteins. Combined with click chemistry, we demonstrate that Ac36AzGalNAc can robustly label O-GlcNAc glycosylation in a wide range of cell lines. Meanwhile, cell imaging and LC-MS/MS proteomics verify its selective activity on O-GlcNAc. More importantly, the protocol presented here provides a general methodology for tracking, capturing and identifying unnatural monosaccharide modified proteins in cells or cell lysates.

Comparison of curative effects between mammotome-assisted minimally invasive resection (MAMIR) and traditional open surgery for gynecomastia in Chinese patients: A prospective clinical study.

To analyze and compare prospectively the curative effects between mammotome-assisted minimally invasive resection (MAMIR) and traditional open surgery (TOS) for gynecomastia in Chinese male patients, a total of 60 patients suffering from grade I and II gynecomastia, evaluated by automated whole-breast ultrasound (AWBU), were recruited and randomly divided into TOS and MAMIR groups (each n = 30). The postoperative scar size, healing time, patient hospital stay, postoperative satisfaction, postoperative pain, and complications including edema and bruising were analyzed. The participants were followed up for 1 week, 1 month, 6 months, and 1 year after surgery. Compared with patients who received TOS, patients in the MAMIR group had significantly smaller scar sizes (0.40 ± 0.08 cm vs 5.34 ± 0.38 cm, P < 0.01), shorter healing times (3.67 ± 0.71 days vs 7.90 ± 0.92 days, P < 0.01), and hospitalization (2.60 ± 0.62 vs 7.17 ± 0.83 days, P < 0.01), as well as higher postoperative satisfaction (4.70 ± 0.60 vs 3.20 ± 0.55 scores, P < 0.01), respectively. Patients in the MAMIR group experienced postoperative mild pain significantly more often than those in the TOS group (6.70 ± 1.06 vs 4.13 ± 0.78 scores, P < 0.01, respectively), but with significantly less postoperative severe pain (53.33% vs 0.00%, P < 0.000). While the incidence rate of edema and bruises was significantly higher in the MAMIR group compared with the TOS group (47% vs 17%, P = 0.013 and 54% vs 20%, P = 0.007, respectively). MAMIR had advantages for curative effects compared with traditional open surgery. However, the recurrence rate in patients needs to be further studied.

Herpes Simplex Virus 1 Induces Phosphorylation and Reorganization of Lamin A/C through the γ134.5 Protein That Facilitates Nuclear Egress.

Herpes simplex virus 1 (HSV-1) remodels nuclear membranes during virus egress. Although the UL31 and UL34 proteins control nucleocapsid transit in infected cells, the molecular interactions required for their function are unclear. Here we report that the γ134.5 gene product of HSV-1 facilitates nucleocapsid release to the cytoplasm through bridging the UL31/UL34 complex, cellular p32, and protein kinase C. Unlike wild-type virus, an HSV mutant devoid of γ134.5 or its amino terminus is crippled for viral growth and release. This is attributable to a defect in virus nuclear egress. In infected cells, wild-type virus recruits protein kinase C to the nuclear membrane and triggers its activation, whereas the γ134.5 mutants fail to exert such an effect. Accordingly, the γ134.5 mutants are unable to induce phosphorylation and reorganization of lamin A/C. When expressed in host cells γ134.5 targets p32 and protein kinase C. Meanwhile, it communicates with the UL31/UL34 complex through UL31. Deletion of the amino terminus from γ134.5 disrupts its activity. These results suggest that disintegration of the nuclear lamina mediated by γ134.5 promotes HSV replication. IMPORTANCE: HSV nuclear egress is a key step that determines the outcome of viral infection. While the nuclear egress complex mediates capsid transit across the nuclear membrane, the regulatory components are not clearly defined in virus-infected cells. We report that the γ134.5 gene product, a virulence factor of HSV-1, facilitates nuclear egress cooperatively with cellular p32, protein kinase C, and the nuclear egress complex. This work highlights a viral mechanism that may contribute to the pathogenesis of HSV infection.

Regulation of Hsf4b nuclear translocation and transcription activity by phosphorylation at threonine 472.

Hsf4b, a key regulator of postnatal lens development, is subjected to posttranslational modifications including phosphorylation. However, the phosphorylation sites in Hsf4b and their biological effects on the transcription activity of Hsf4b are poorly understood. Here we examined 17 potential phosphorylation residues in Hsf4b with alanine-scanning assays and found that a T472A mutation diminished Hsf4b-mediated expression of Hsp25 and alphaB-crystallin. In contrast, the phosphomimetic mutation of T472D enhanced their expression. Further investigation demonstrated that Hsf4b could interact with nuclear-transporter importin beta-1 and Hsc70 via amino acids 246-320 and 320-493, respectively. T472A mutation reduced Hsf4bs interaction with importin beta-1, while enhancing its interaction with Hsc7O, resulting in Hsf4b cytosolic re-localization, protein instability and transcription activity attenuation. At the upstream, MEK6 was found to interact with Hsf4b and enhance Hsf4b's nuclear translocation and transcription activity, probably by phosphorylation at sites such as T472. Taken together, our results suggest that phosphotylation of Hsf4b at T472 by protein kinases such as MEI(6 regulates Hsf4b interaction with the importin V I -Hsc7O complex, resulting in blockade of its nuclear translocation and transcriptional activity of Hsf4b.

Malate, a natural inhibitor of 6PGD, improves the efficacy of chemotherapy in lung cancer.

OBJECTIVE: Metabolic reprogramming is an important coordinator of tumor development and resistance to therapy, such as the tendency of tumor cells to utilize glycolytic energy rather than oxidative phosphorylation, even under conditions of sufficient oxygen. Therefore, targeting metabolic enzymes is an effective strategy to overcome therapeutic resistance. MATERIALS AND METHODS: We explored the differential expression and growth-promoting function of MDH2 by immunohistochemistry and immunoblotting experiments in lung cancer patients and lung cancer cells. Pentose phosphate pathway-related phenotypes (including ROS levels, NADPH levels, and DNA synthesis) were detected intracellularly, and the interaction of malate and proteinase 6PGD was detected in vitro. In vivo experiments using implanted xenograft mouse models to explore the growth inhibitory effect and pro-chemotherapeutic function of dimethyl malate (DMM) on lung cancer. RESULTS: We found that the expression of malate dehydrogenase (MDH2) in the tricarboxylic acid cycle (TCA cycle) was increased in lung cancer. Biological function enrichment analysis revealed that MDH2 not only promoted oxidative phosphorylation, but also promoted the pentose phosphate pathway (PPP pathway). Mechanistically, it was found that malate, the substrate of MDH2, can bind to the PPP pathway metabolic enzyme 6PGD, inhibit its activity, reduce the generation of NADPH, and block DNA synthesis. More importantly, DMM can improve the sensitivity of lung cancer to the clinical drug cisplatin. CONCLUSION: We have identified malate as a natural inhibitor of 6PGD, which will provide new leads for the development of 6PGD inhibitors. In addition, the metabolic enzyme MDH2 and the metabolite malate may provide a backup option for cells to inhibit their own carcinogenesis, as the accumulated malate targets 6PGD to block the PPP pathway and inhibit cell cycle progression.

Transcriptome analysis identifies genetic risk markers and explores the pathogenesis for inflammatory bowel disease.

Inflammatory bowel disease (IBD) is an incurable and disabling bowel disease driven by multiple risk factors that severely limit patients' quality of life. We integrated the RNA-sequencing data of 1238 IBD patients, and investigated the pathogenesis of IBD by combining transcriptional element prediction analysis and immune-related analysis. Here, we first determined that KIAA1109 is inhibited in IBD patients. The expression of KIAA1109 and NOD2, the key receptor of NOD-like receptors, showed a negative correlation. The NOD-like receptor signaling pathway is activated and exerts transcriptional regulation on the chemokines CXCL1 and CXCL2 through the activation of the transcription factors NFκB and AP1. Analysis of immune infiltration revealed that the expression of chemokines CXCL1 and CXCL2 may regulate the inflammatory response induced by immune cells. These findings suggest that the KIAA1109-NOD2-NFκB/AP1-CXCL1/CXCL2 regulatory axis is the molecular mechanism of IBD pathogenesis, which will provide a new perspective for the diagnosis, treatment and management of IBD patients.

Targeting FTO induces colorectal cancer ferroptotic cell death by decreasing SLC7A11/GPX4 expression.

Ferroptosis is a newly identified iron-dependent form of death that is becoming increasingly recognized as a promising avenue for cancer therapy. N6-methyladenosine (m6A) is the most abundant reversible methylation modification in mRNA contributing to tumorigenesis. However, the crucial role of m6A modification in regulating ferroptosis during colorectal cancer (CRC) tumorigenesis remains elusive. Herein, we find that m6A modification is increased during ferroptotic cell death and correlates with the decreased m6A demethylase fat mass and obesity-associated protein (FTO) expression. Functionally, we demonstrate that suppressing FTO significantly induces CRC ferroptotic cell death, as well as enhancing CRC cell sensitivity to ferroptosis inducer (Erastin and RSL3) treatment. Mechanistically, high FTO expression increased solute carrier family 7 member 11 (SLC7A11) or glutathione peroxidase 4 (GPX4) expressions in an m6A-YTHDF2 dependent manner, thereby counteracting ferroptotic cell death stress. In addition, we identify Mupirocin as a novel inhibitor of FTO, and Mupirocin induces CRC ferroptosis and inhibits tumor growth. Clinically, the levels of FTO, SLC7A11, and GPX4, are highly correlated expression in CRC tissues. Our findings reveal that FTO protects CRC from ferroptotic cell death in promoting CRC tumorigenesis through triggering SLC7A11/GPX4 expression.

[Establishment of mouse lens epithelial cell lines with the genotype of Hsf4-/-].

OBJECTIVE: To establish mouse lens epithelial cell lines with the genotype of Hsf4-/-. METHODS: The expended mouse lens epithelial cells, which were generated from P6 Hsf4-deficient mouse lens epithelia, were immortalized with SV40-T-antigen and named MLEC/Hsf4-/- cell. The expression of alpha A-crystallin was immunoblotted. Hsf4b cDNA was reconstituted by transiently transfection. RESULTS: The SV40-immortalized cells were in adherent growth mode with spindle morphology, pseudopodia, clear nuclear boundary membrane and cytoplasm translucent. Immunoblotting results indicated that the lens biomarker protein alpha A-crystallin was expressed in MLEC/Hsf4-/- cells. Reconstitution of Hsf4b into MLEC/Hsf4-/- cells upregulated the expression of Hsp25. CONCLUSIONS: The SV40-immortalized MLEC/Hsf4-/- cells have the lens epithelial characteristics and could be used as a tool for studying the signal transduction in vitro.

A model for identification of potential phase-separated proteins based on protein sequence, structure and cellular distribution.

The cells are like a highly industrialized and urbanized city, filled with numerous biological macromolecules and metabolites, forming a crowded environment. While, the cells have compartmentalized organelles to complete different biological processes efficiently and orderly. However, membraneless organelles are more dynamic and adaptable for transient events including signal transduction and molecular interactions. Liquid-liquid phase separation (LLPS) is a mechanism that is widespread in which macromolecules form condensates without membranes to exert biological functions in crowded environments. Due to the lack of deep understanding of phase-separated proteins, platforms exploring phase-separated proteins by high-throughput methods is lacking. Bioinformatics has its unique properties and has proven to be a great impetus in multiple fields. Here, We integrated the amino acid sequence, protein structure, and cellular localization, then developed a workflow for screening phase-separated proteins and identified a novel cell cycle-related phase separation protein, serine/arginine-rich splicing factor 2 (SRSF2). In conclusion, we developed a workflow as a useful resource for predicting phase-separated proteins based on multi-prediction tool, which has an important contribution to the further identification of phase-separated proteins and the development strategies for treating disease.